1. |
- Sällström, Johan, et al.
(author)
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High-protein-induced glomerular hyperfiltration is independent of the tubuloglomerular feedback mechanism and nitric oxide synthases
- 2010
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In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 299:5, s. R1263-R1268
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Journal article (peer-reviewed)abstract
- A high protein intake is associated with increased glomerular filtration rate (GFR), which has been suggested to be mediated by reduced signaling of the tubuloglomerular feedback (TGF) mechanism. Nitric oxide (NO) has been shown to contribute to high protein-induced glomerular hyperfiltration, but the specific NO synthase (NOS) isoform responsible is not clear. In this study, a model for high-proteininduced hyperfiltration in conscious mice was developed. Using this model, we investigated the role of TGF using adenosine A(1)-receptor knockout mice lacking the TGF mechanism. Furthermore, the role of the different NOS isoforms was studied using neuronal-, inducible-, and endothelial-NOS knockout mice, and furthermore, wild-type mice acutely administered with the unspecific NOS inhibitor N-omega-nitro-L-arginine methyl ester (100 mg/kg). GFR was measured consecutively in mice given a low-protein diet (8% casein) for 10 days, followed by a high-protein diet (50% casein) for 10 days. All mice developed high protein-induced hyperfiltration to a similar degree. These results demonstrate that high protein-induced glomerular hyperfiltration is independent of the TGF mechanism and NOS isoforms.
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2. |
- Al-Mashhadi, Ammar Nadhom Farman, et al.
(author)
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Changes in arterial pressure and markers of nitric oxide homeostasis and oxidative stress following surgical correction of hydronephrosis in children
- 2018
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In: Pediatric nephrology (Berlin, West). - : Springer. - 0931-041X .- 1432-198X. ; 33:4, s. 639-649
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Journal article (peer-reviewed)abstract
- Objective Recent clinical studies have suggested an increased risk of elevated arterial pressure in patients with hydronephrosis. Animals with experimentally induced hydronephrosis develop hypertension, which is correlated to the degree of obstruction and increased oxidative stress. In this prospective study we investigated changes in arterial pressure, oxidative stress, and nitric oxide (NO) homeostasis following correction of hydronephrosis.Methods Ambulatory arterial pressure (24 h) was monitored in pediatric patients with hydronephrosis (n = 15) before and after surgical correction, and the measurements were compared with arterial pressure measurements in two control groups, i.e. healthy controls (n = 8) and operated controls (n = 8). Markers of oxidative stress and NO homeostasis were analyzed in matched urine and plasma samples.Results The preoperative mean arterial pressure was significantly higher in hydronephrotic patients [83 mmHg; 95% confidence interval (CI) 80–88 mmHg] than in healthy controls (74 mmHg; 95% CI 68–80 mmHg; p < 0.05), and surgical correction of ureteral obstruction reduced arterial pressure (76 mmHg; 95% CI 74–79 mmHg; p < 0.05). Markers of oxidative stress (i.e., 11- dehydroTXB2, PGF2α, 8-iso-PGF2α, 8,12-iso-iPF2α-VI) were significantly increased (p < 0.05) in patients with hydronephrosis compared with both control groups, and these were reduced following surgery (p < 0.05). Interestingly, there was a trend for increased NO synthase activity and signaling in hydronephrosis, which may indicate compensatory mechanism(s).Conclusion This study demonstrates increased arterial pressure and oxidative stress in children with hydronephrosis compared with healthy controls, which can be restored to normal levels by surgical correction of the obstruction. Once reference data on ambulatory blood pressure in this young age group become available, we hope cut-off values can be defined for deciding whether or not to correct hydronephrosis surgically.Keywords Blood pressure . Hydronephrosis . Hypertension . Nitric oxide . Oxidative stress . Ureteral obstruction
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3. |
- Al-Mashhadi, Ammar Nadhom Farman
(author)
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High Blood Pressure in Children with Hydronephrosis
- 2018
-
Doctoral thesis (other academic/artistic)abstract
- The most common cause of secondary hypertension is intrinsic renal disease, but little is known about the influence of hydronephrosis on blood pressure. In this thesis, the risk of development of hypertension in children with hydronephrosis was studied.Experimental and clinical studies were combined in order to investigate the risk of developing elevated blood pressure following conservative treatment of hydronephrosis, and to further explore underlying mechanisms. We started with a clinical study in children (study I), which in agreement with previous experimental studies, showed that blood pressure was lowered by surgical management of hydronephrosis. In parallel, an experimental study was conducted (study II) to investigate the involvement of renal sympathetic nerve activity in development of hypertension following induction of hydronephrosis caused by pelvo-ureteric junction obstruction. Renal denervation of the obstructed kidney attenuated hypertension and restored the renal excretion pattern, effects that were associated with reduced activity of both renal NADPH oxidase derived oxidative stress and components of the renin-angiotensin-aldosterone system.Based on the findings in studies I and II, we continued our studies in children with hydronephrosis, and including two control groups as comparisons with the hydronephrotic group (study III). In the same study, we further investigated potential mechanism(s) of hypertension by analyzing markers of oxidative stress and nitric oxide homeostasis in both urine and blood samples. We demonstrated increased arterial pressure and oxidative stress in children with hydronephrosis compared with healthy controls, which was restored to normal levels by surgical correction of the obstruction. Finally, in a retrospective cohort study, blood pressure of adult patients undergoing surgical management of hydronephrosis due to pelvo-ureteric junction obstruction was assessed (study IV). Similar to that demonstrated in the pediatric hydronephrotic population, blood pressure was significantly reduced by relief of the obstruction. In addition, blood pressure was increased again if the hydronephrosis recurred, and was reduced again following re-operation.It is concluded that conservative management of hydronephrosis in children is associated with a risk for development of high blood pressure, which can be reduced or even normalized by relief of the obstruction. The mechanism(s), at least in part, is coupled to increased oxidative stress.
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4. |
- Bertolino, Mattias, et al.
(author)
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Thomas-Reiche-Kuhn correction for truncated configuration-interaction spaces : Case of laser-assisted dynamical interference
- 2022
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In: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 106:4
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Journal article (peer-reviewed)abstract
- The Thomas-Reiche-Kuhn sum rule is used to form an effective potential that is added to the time-dependent configuration-interaction singles (TDCIS) equations of motion in velocity gauge. The purpose of the effective potential is to include virtual coupling from singles to doubles, which is required for size-consistent velocity-gauge TDCIS results. The proposed method is compared to length-gauge TDCIS results for laser-assisted photoionization. Finally, a dynamical interference effect controlled by two-color fields is predicted for atomic targets.
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5. |
- Broman, Lars Mikael, et al.
(author)
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Effect of nitric oxide on renal autoregulation during hypothermia in the rat.
- 2017
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In: Pflügers Archiv. - : Springer Science and Business Media LLC. - 0031-6768 .- 1432-2013. ; 469:5-6, s. 669-680
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Journal article (peer-reviewed)abstract
- Hypothermia-induced reduction of metabolic rate is accompanied by depression of both glomerular perfusion and filtration. The present study investigated whether these changes are linked to changes in renal autoregulation and nitric oxide (NO) signalling. During hypothermia, renal blood flow (RBF) and glomerular filtration rate (GFR) were reduced and urine production was increased, and this was linked with reduced plasma cGMP levels and increased renal vascular resistance. Although stimulation of NO production decreased vascular resistance, blood pressure and urine flow, intravenous infusion of the NO precursor L-arginine or the NO donor sodium nitroprusside did not alter RBF or GFR. In contrast, inhibition of NO synthesis by N(w)-nitro-L-arginine led to a further decline in both parameters. Functional renal autoregulation was apparent at both temperatures. Below the autoregulatory range, RBF in both cases increased in proportion to the perfusion ±pressure, although, the slope of the first ascending limb of the pressure-flow relationship was lower during hypothermia. The main difference was rather that the curves obtained during hypothermia levelled off already at a RBF of 3.9 ± 0.3 mL/min then remained stable throughout the autoregulatory pressure range, compared to 7.6 ± 0.3 mL/min during normothermia. This was found to be due to a threefold increase in, primarily, the afferent arteriolar resistance from 2.6 to 7.5 mmHg min mL(-1). Infusion of sodium nitroprusside did not significantly affect RBF during hypothermia, although a small increase at pressures below the autoregulatory range was observed. In conclusion, cold-induced rise in renal vascular resistance results from afferent arteriolar vasoconstriction by the autoregulatory mechanism, setting RBF and GFR in proportion to the metabolic rate, which cannot be explained by reduced NO production alone.
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6. |
- Brown, Russell D., et al.
(author)
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Tubuloglomerular feedback response in the prenatal and postnatal ovine kidney
- 2011
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In: American Journal of Physiology - Renal Physiology. - : American Physiological Society. - 0363-6127 .- 1522-1466 .- 1931-857X. ; 300:6, s. F1368-F1374
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Journal article (peer-reviewed)abstract
- Brown RD, Turner AJ, Carlstrom M, Persson AE, Gibson KJ. Tubuloglomerular feedback response in the prenatal and postnatal ovine kidney. Am J Physiol Renal Physiol 300: F1368-F1374, 2011. First published March 30, 2011; doi:10.1152/ajprenal. 00019.2011.-The tubuloglomerular feedback mechanism (TGF) plays an important role in regulating single-nephron glomerular filtration rate (GFR) by coupling distal tubular flow to arteriolar tone. It is not known whether TGF is active in the developing kidney or whether it can regulate renal vascular tone and thus GFR during intrauterine life. TGF characteristics were examined in late-gestation ovine fetuses and lambs under normovolemic and volume-expanded (VE) conditions. Lambs and pregnant ewes were anesthetized and the fetuses were delivered via a caesarean incision into a heated water bath, with the umbilical cord intact. Under normovolemic conditions, mean arterial pressure of the fetuses was lower than lambs (51 +/- 1 vs. 64 +/- 3 mmHg). The maximum TGF response (Delta P(SFmax)) was found to be lower in fetuses than lambs when tubular perfusion was increased from 0 to 40 nl/min (5.4 +/- 0.7 vs. 10.6 +/- 0.4 mmHg). Furthermore, the flow rate eliciting half-maximal response [turning point (TP)] was 15.7 +/- 0.9 nl/min in fetuses compared with 19.3 +/- 1.0 nl/min in lambs, indicating a greater TGF sensitivity of the prenatal kidney. VE decreased Delta P(SFmax) (4.2 +/- 0.4 mmHg) and increased TP to 23.7 +/- 1.3 nl/min in lambs. In fetuses, VE increased stop-flow pressure from 26.6 +/- 1.5 to 30.3 +/- 0.8 mmHg, and reset TGF sensitivity so that TP increased to 21.3 +/- 0.7 nl/min, but it had no effect on Delta P(SFmax). This study provides direct evidence that the TGF mechanism is active during fetal life and responds to physiological stimuli. Moreover, reductions in TGF sensitivity may contribute to the increase in GFR at birth.
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7. |
- Carlström, Mattias, et al.
(author)
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Angiogenesis inhibition causes hypertension and placental dysfunction in a rat model of preeclampsia
- 2009
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In: Journal of Hypertension. - 0263-6352 .- 1473-5598. ; 27:4, s. 829-837
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Journal article (peer-reviewed)abstract
- Background Preeclampsia is a serious pregnancy complication, accompanied by increased maternal and fetal morbidity. Different models have been used to study preeclampsia, but none of these display all the key features of the disease. Method We investigated the effects on maternal blood pressure and fetal outcome exerted by the angiogenesis inhibitor Suramin (1100 mg/kg i.p.) during early placentation. Blood pressure and heart rate were measured continuously with telemetry in Sprague - Dawley rats of four experimental groups: nonpregnant controls, Suramin-treated nonpregnant rats, pregnant controls and pregnant Suramin-treated rats. Blood samples were collected before pregnancy and at gestational day 20 for analysis of renin and sFIt-1. The fetal and placental morphology were evaluated after caesarian section on gestational day 20. Results The blood pressure of the pregnant Suramin-treated rats successively increased during pregnancy and differed by 17 mmHg at gestational day 20 compared with the pregnant control rats. In the pregnant Suramin-treated rats group, the renin levels increased (+122%) and the sFIt-1 levels decreased (-58%) during pregnancy. The pregnant Suramin-treated fetuses and placentae were smaller (2.8 g and 0.51 g) than the pregnant controls rats' fetuses and placentae (3.5g and 0.56g). Resorptions tended to be higher in the pregnant Suramin-treated rat litters compared with the pregnant control rat litters (P = 0.08). The area of the maternal blood vessels in the mesometrial triangle was smaller in the pregnant Suramin-treated rats group than in the pregnant control rats group. Conclusion The inhibition of uterine angiogenesis increases maternal blood pressure and compromises fetal and placental development. Placental hypoxia and subsequent activation of the renin-angiotensin system may play an important role for the hypertension. J Hypertens 27:829-837 (C) 2009 Wolters Kluwer Health | Lippincott Williams & Wilkins.
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8. |
- Carlström, Mattias
(author)
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Causal link between neonatal hydronephrosis and later development of hypertension
- 2010
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In: Clinical and experimental pharmacology & physiology. - : Wiley. - 0305-1870 .- 1440-1681. ; 37:2, s. E14-E23
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Journal article (peer-reviewed)abstract
- 1. Although congenital ureteral obstruction is a common disorder in infants, its pathophysiology remains poorly understood and its clinical management continues to be debated. During the past decade, the surgical management of non-symptomatic hydronephrosis in children has become more conservative, but the long-term physiological consequences of this new policy are unclear. 2. In experimental models with complete ureteral obstruction, tubular atrophy and interstitial inflammation occur rapidly. Although this type of obstruction is very rare in clinical practice, it is often referred to in clinical discussions. New studies, using a model with chronic partial ureteral obstruction, have demonstrated that hydronephrosis is associated with renal injuries and is causally related to hypertension. 3. The mechanisms underlying the development of hypertension in experimental hydronephrosis are complex and involve changes in both the renin-angiotensin system and renal sympathetic nerve activity. Furthermore, oxidative stress and nitric oxide deficiency in the diseased kidney, with consequent resetting of the tubuloglomerular feedback mechanism, appear to play a pivotal role in the development and maintenance of hypertension. 4. In view of the new knowledge regarding the long-term effects of partial ureteral obstruction, today's non-operative management of hydronephrosis should be reconsidered to prevent obstructive nephropathy and hypertension in later life.
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9. |
- Carlström, Mattias, et al.
(author)
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Coffee consumption and reduced risk of developing type 2 diabetes : a systematic review with meta-analysis.
- 2018
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In: Nutrition reviews. - : Oxford University Press (OUP). - 0029-6643 .- 1753-4887. ; 76:6, s. 395-417
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Journal article (peer-reviewed)abstract
- Context: Type 2 diabetes (T2D) is a major health problem worldwide that is associated with increased morbidity and mortality. There is increased interest in the value of different nutrition-based strategies for preventing the development of T2D.Objective: This review aims to cover current knowledge regarding the effects of coffee consumption on development of T2D or modulation of adverse complications. A meta-analysis on coffee consumption and the risk of T2D was conducted. Moreover, bioactive components in coffee, polymorphisms, and potential underlying mechanism(s) in relation to T2D and adverse complications are discussed.Data sources: PubMed was searched up to December 1, 2017, and prospective cohort and nested case-control studies of the association between coffee consumption and T2D risk were selected.Data extraction: Two investigators independently extracted data from included studies.Results: A total of 30 prospective studies with 1 185 210 participants and 53 018 incident T2D cases were included in the meta-analysis. The pooled relative risk (RR) was 0.71 (95% confidence interval [CI], 0.67-0.76) for the highest category of coffee consumption (median consumption, 5 cups/d) vs the lowest category (median consumption, 0 cups/d). The risk of T2D decreased by 6% (RR = 0.94; 95%CI, 0.93-0.95) for each cup-per-day increase in coffee consumption. Results were similar for caffeinated coffee consumption (per additional cup of coffee per day: RR = 0.93; 95%CI, 0.90-0.96) and decaffeinated coffee consumption (corresponding RR = 0.94; 95%CI, 0.90-0.98).Conclusions: Available evidence indicates that coffee consumption is inversely associated with risk of T2D. Possible mechanisms behind this association include thermogenic, antioxidative, and anti-inflammatory effects; modulation of adenosine receptor signaling; and microbiome content and diversity.
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10. |
- Carlström, Mattias, et al.
(author)
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Cross-talk Between Nitrate-Nitrite-NO and NO Synthase Pathways in Control of Vascular NO Homeostasis
- 2015
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In: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 23:4, s. 295-306
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Journal article (peer-reviewed)abstract
- Aims: Inorganic nitrate and nitrite from endogenous and dietary sources have emerged as alternative substrates for nitric oxide (NO) formation in addition to the classic L-arginine NO synthase (NOS)-dependent pathway. Here, we investigated a potential cross-talk between these two pathways in the regulation of vascular function. Results: Long-term dietary supplementation with sodium nitrate (0.1 and 1mmol kg(-1) day(-1)) in rats caused a reversible dose-dependent reduction in phosphorylated endothelial NOS (eNOS) (Ser1177) in aorta and a concomitant increase in phosphorylation at Thr495. Moreover, eNOS-dependent vascular responses were attenuated in vessels harvested from nitrate-treated mice or when nitrite was acutely added to control vessels. The citrulline-to-arginine ratio in plasma, as a measure of eNOS activity, was reduced in nitrate-treated rodents. Telemetry measurements revealed that a low dietary nitrate dose reduced blood pressure, whereas a higher dose was associated with a paradoxical elevation. Finally, plasma cyclic guanosine monophosphate increased in mice that were treated with a low dietary nitrate dose and decreased with a higher dose. Innovation and Conclusions: These results demonstrate the existence of a cross-talk between the nitrate-nitrite-NO pathway and the NOS-dependent pathway in control of vascular NO homeostasis. Antioxid. Redox Signal. 23, 295-306.
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11. |
- Carlström, Mattias, 1978-
(author)
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Development of Salt-Sensitive Hypertension in Hydronephrosis
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Hydronephrosis, due to ureteropelvic junction obstruction, is a common condition in infants with an incidence of approximately 0.5-1%. During the last decade, the surgical management of non-symptomatic hydronephrosis has become more conservative, and the long-term physiological consequences of this new policy are unclear. The overall aim of this thesis was to determine whether there is a link between hydronephrosis and the development of hypertension. Hydronephrosis was induced by partial ureteral obstruction in 3-week old rats or mice. In the adult animals, blood pressure was measured telemetrically during different sodium conditions and the renal function was evaluated. Both species developed salt-sensitive hypertension and histopathological changes (i.e. fibrosis, inflammation, glomerular and tubular changes) that correlated with the degree of hydronephrosis. An abnormal renal excretion pattern with increased diuresis and impaired urine concentrating ability was observed in hydronephrosis. The mechanisms were primarily located to the diseased kidney, as relief of the obstruction attenuated blood pressure and salt-sensitivity. Increased renin angiotensin system activity, due to ureteral obstruction, might be involved in the development but not necessary the maintenance of hypertension. Hydronephrotic animals displayed reduced nitric oxide availability, which might be due to increased oxidative stress in the diseased kidney. Renal nitric oxide deficiency and subsequent resetting of the tubuloglomerular feedback mechanism, appeared to have an important role in the development of hypertension. In conclusion, experimental hydronephrosis, induced by partial ureteral obstruction, provides a new model for studies of salt-sensitive hypertension. Furthermore, the new findings imply that the current conservative treatment strategy in hydronephrosis should be reconsidered in favour of treatment that is more active, in order to prevent the development of renal injury and hypertension in later life.
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12. |
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13. |
- Carlström, Mattias, et al.
(author)
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Dietary inorganic nitrate reverses features of metabolic syndrome in endothelial nitric oxide synthase-deficient mice
- 2010
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In: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 107:41, s. 17716-17720
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Journal article (peer-reviewed)abstract
- The metabolic syndrome is a clustering of risk factors of metabolic origin that increase the risk for cardiovascular disease and type 2 diabetes. A proposed central event in metabolic syndrome is a decrease in the amount of bioavailable nitric oxide (NO) from endothelial NO synthase (eNOS). Recently, an alternative pathway for NO formation in mammals was described where inorganic nitrate, a supposedly inert NO oxidation product and unwanted dietary constituent, is serially reduced to nitrite and then NO and other bioactive nitrogen oxides. Here we show that several features of metabolic syndrome that develop in eNOS-deficient mice can be reversed by dietary supplementation with sodium nitrate, in amounts similar to those derived from eNOS under normal conditions. In humans, this dose corresponds to a rich intake of vegetables, the dominant dietary nitrate source. Nitrate administration increased tissue and plasma levels of bioactive nitrogen oxides. Moreover, chronic nitrate treatment reduced visceral fat accumulation and circulating levels of triglycerides and reversed the prediabetic phenotype in these animals. In rats, chronic nitrate treatment reduced blood pressure and this effect was also present during NOS inhibition. Our results show that dietary nitrate fuels a nitrate-nitrite-NO pathway that can partly compensate for disturbances in endogenous NO generation from eNOS. These findings may have implications for novel nutrition-based preventive and therapeutic strategies against cardiovascular disease and type 2 diabetes.
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14. |
- Carlström, Mattias, 1941-, et al.
(author)
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Dietary nitrate attenuates oxidative stress, prevents cardiac and renal injuries, and reduces blood pressure in salt-induced hypertension
- 2011
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 89:3, s. 574-585
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Journal article (peer-reviewed)abstract
- Aims Reduced bioavailability of endogenous nitric oxide (NO) is a central pathophysiological event in hypertension and other cardiovascular diseases. Recently, it was demonstrated that inorganic nitrate from dietary sources is converted in vivo to form nitrite, NO, and other bioactive nitrogen oxides. We tested the hypothesis that dietary inorganic nitrate supplementation may have therapeutic effects in a model of renal and cardiovascular disease. Methods and results Sprague-Dawley rats subjected to unilateral nephrectomy and chronic high-salt diet from 3 weeks of age developed hypertension, cardiac hypertrophy and fibrosis, proteinuria, and histological as well as biochemical signs of renal damage and oxidative stress. Simultaneous nitrate treatment (0.1 or 1 mmol nitrate kg(-1) day(-1)), with the lower dose resembling the nitrate content of a diet rich in vegetables, attenuated hypertension dose-dependently with no signs of tolerance. Nitrate treatment almost completely prevented proteinuria and histological signs of renal injury, and the cardiac hypertrophy and fibrosis were attenuated. Mechanistically, dietary nitrate restored the tissue levels of bioactive nitrogen oxides and reduced the levels of oxidative stress markers in plasma (malondialdehyde) and urine (Class VI F2-isoprostanes and 8-hydroxy-2-deoxyguanosine). In addition, the increased circulating and urinary levels of dimethylarginines (ADMA and SDMA) in the hypertensive rats were normalized by nitrate supplementation. Conclusion Dietary inorganic nitrate is strongly protective in this model of renal and cardiovascular disease. Future studies will reveal if nitrate contributes to the well-known cardioprotective effects of a diet rich in vegetables.
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15. |
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16. |
- Carlström, Mattias, et al.
(author)
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Hydronephrosis causes salt-sensitive hypertension and impaired renal concentrating ability in mice
- 2007
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In: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 189:3, s. 293-301
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Journal article (peer-reviewed)abstract
- Aim: Hypertension is a common disease in the industrialized world and approximately 5% of all cases are secondary to kidney malfunction. We have recently shown that hydronephrosis due to partial unilateral ureteral obstruction (PUUO) causes salt-sensitive hypertension in rats. The mechanisms are still unclear, but appear to be intrarenal and primarily located to the diseased kidney. In the present study, we have developed a model for PUUO to study if hydronephrotic mice develop salt-sensitive hypertension. Methods: PUUO was created in 3-week-old mice (C57bl/6J). Blood pressure and heart rate were measured telemetrically in adult animals on normal and high salt diets. Metabolism cages were used to study the renal excretion of electrolytes and water. Plasma samples for renin analysis were collected and renal histological changes were evaluated. Results: All hydronephrotic animals developed salt-sensitive hypertension that correlated to the degree of hydronephrosis. In hydronephrotic animals, blood pressure increased from 114 ± 1 mmHg on normal salt diet to 120 ± 2 mmHg on high salt diet, compared with 103 ± 1 to 104 ± 1 in controls. Hydronephrotic animals showed increased diuresis and reduced ability to regulate electrolyte concentration. No differences in plasma renin concentration were found between the groups. The parenchymal weight and glomerular area of contralateral kidneys were significantly increased in the hydronephrotic animals. Histopathology of the hydronephrotic kidneys displayed areas with fibrosis, inflammation and glomerular changes. Conclusion: This study provides a model for PUUO in mice and demonstrates the presence of salt-sensitive hypertension and an impaired renal concentrating ability in mice which has not been described before.
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17. |
- Carlström, Mattias, et al.
(author)
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Hydronephrosis causes salt-sensitive hypertension in rats
- 2006
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In: Journal of Hypertension. - : Ovid Technologies (Wolters Kluwer Health). - 0263-6352 .- 1473-5598. ; 24:7, s. 1437-1443
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Journal article (peer-reviewed)abstract
- BACKGROUND: Hypertension is a common disease in the Western world and approximately 5% of all cases are secondary to kidney malfunction. It is not clear whether unilateral hydronephrosis due to partial obstruction affects blood pressure. AIM: The aim of this study was to determine whether hypertension develops and to investigate the effects of different salt diets on the blood pressure in hydronephrotic animals. METHODS: Unilateral partial ureteral obstruction was created in 3-week-old Sprague-Dawley rats. A telemetric device was implanted 4-6 weeks later and blood pressure was measured on normal, low- and high-salt diets. Plasma samples were collected on all diets for renin analysis. RESULTS: All hydronephrotic animals developed hypertension that correlated to the degree of hydronephrosis. The blood pressure increased slowly with time and was salt sensitive. In severe hydronephrosis, blood pressure increased from 118 ± 5 mmHg on low salt to 140 ± 6 mmHg on high salt intake, compared to control levels of 82 ± 2 and 84 ± 2 mmHg, respectively. Plasma renin concentration was increased in the hydronephrotic group of animals compared to controls on all diets, but the difference was only significant on a normal salt diet, 165 ± 15 versus 86 ± 12 μGU/ml respectively. In animals with severe hydronephrosis the plasma renin levels were lower, and the changes less, than in those with mild and moderate hydronephrosis. CONCLUSION: This study demonstrates the presence of a salt-sensitive hypertension in hydronephrosis. A systemic effect of the renin-angiotensin system alone cannot be responsible for the hypertension.
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18. |
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19. |
- Carlström, Mattias, et al.
(author)
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L-arginine or tempol supplementation improves renal and cardiovascular function in rats with reduced renal mass and chronic high salt intake
- 2013
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In: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 207:4, s. 732-741
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Journal article (peer-reviewed)abstract
- Aim Early life reduction in nephron number and chronic high salt intake cause development of renal and cardiovascular disease, which has been associated with oxidative stress and nitric oxide (NO) deficiency. We investigated the hypothesis that interventions stimulating NO signalling or reducing oxidative stress may restore renal autoregulation, attenuate hypertension and reduce renal and cardiovascular injuries following reduction in renal mass and chronic high salt intake. Methods Male SpragueDawley rats were uninephrectomized (UNX) or sham-operated at 3weeks of age and given either a normal-salt (NS) or high-salt (HS) diet. Effects on renal and cardiovascular functions were assessed in rats supplemented with substrate for NO synthase (L-Arg) or a superoxide dismutase mimetic (Tempol). Results Rats with UNX+HS developed hypertension and displayed increased renal NADPH oxidase activity, elevated levels of oxidative stress markers in plasma and urine, and reduced cGMP in plasma. Histological analysis showed signs of cardiac and renal inflammation and fibrosis. These changes were linked with abnormal renal autoregulation, measured as a stronger tubuloglomerular feedback (TGF) response. Simultaneous treatment with L-Arg or Tempol restored cGMP levels in plasma and increased markers of NO signalling in the kidney. This was associated with normalized TGF responses, attenuated hypertension and reduced signs of histopathological changes in the kidney and in the heart. Conclusion Reduction in nephron number during early life followed by chronic HS intake is associated with oxidative stress, impaired renal autoregulation and development of hypertension. Treatment strategies that increase NO bioavailability, or reduce levels of reactive oxygen species, were proven beneficial in this model of renal and cardiovascular disease.
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20. |
- Carlström, Mattias, et al.
(author)
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Nitric oxide deficiency and increased adenosine response of afferent arterioles in hydronephrotic mice with hypertension
- 2008
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In: Hypertension. - : American Heart Association. - 0194-911X .- 1524-4563. ; 51:5, s. 1386-1392
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Research review (peer-reviewed)abstract
- Afferent arterioles were used to investigate the role of adenosine, angiotensin II, NO, and reactive oxygen species in the pathogenesis of increased tubuloglomerular feedback response in hydronephrosis. Hydronephrosis was induced in wild-type mice, superoxide dismutase-1 overexpressed mice (superoxide-dismutase-1 transgenic), and deficient mice (superoxide dismutase-1 knockout). Isotonic contractions in isolated perfused arterioles and mRNA expression of NO synthase isoforms, adenosine, and angiotensin II receptors were measured. In wild-type mice, N(G)-nitro-L-arginine methyl ester (L-NAME) did not change the basal arteriolar diameter of hydronephrotic kidneys (-6%) but reduced it in control (-12%) and contralateral arterioles (-43%). Angiotensin II mediated a weaker maximum contraction of hydronephrotic arterioles (-18%) than in control (-42%) and contralateral arterioles (-49%). The maximum adenosine-induced constriction was stronger in hydronephrotic (-19%) compared with control (-8%) and contralateral kidneys (+/-0%). The response to angiotensin II became stronger in the presence of adenosine in hydronephrotic kidneys and attenuated in contralateral arterioles. L-NAME increased angiotensin II responses of all of the groups but less in hydronephrotic kidneys. The mRNA expression of endothelial NO synthase and inducible NO synthase was upregulated in the hydronephrotic arterioles. No differences were found for adenosine or angiotensin II receptors. In superoxide dismutase-1 transgenic mice, strong but similar L-NAME response (-40%) was observed for all of the groups. This response was totally abolished in arterioles of hydronephrotic superoxide dismutase-1 knockout mice. In conclusion, hydronephrosis is associated with changes in the arteriolar reactivity of both hydronephrotic and contralateral kidneys. Increased oxidative stress, reduced NO availability, and stronger reactivity to adenosine of the hydronephrotic kidney may contribute to the enhanced tubuloglomerular feedback responsiveness in hydronephrosis and be involved in the development of hypertension.
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21. |
- Carlström, Mattias, et al.
(author)
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Peritoneal dialysis impairs nitric oxide homeostasis and may predispose infants with low systolic blood pressure to cerebral ischemia
- 2016
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In: Nitric Oxide - Biology and Chemistry. - : Elsevier BV. - 1089-8603 .- 1089-8611. ; 58, s. 1-9
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Journal article (peer-reviewed)abstract
- Background & purpose Infants on chronic peritoneal dialysis (PD) have an increased risk of developing neurological morbidities; however, the underlying biological mechanisms are poorly understood. In this clinical study, we investigated whether PD-mediated impairment of nitric oxide (NO) bioavailability and signaling, in patients with persistently low systolic blood pressure (SBP), can explain the occurrence of cerebral ischemia. Methods & results Repeated blood pressure measurements, serial neuroimaging studies, and investigations of systemic nitrate and nitrite levels, as well as NO signaling, were performed in ten pediatric patients on PD. We consistently observed the loss of both inorganic nitrate (-17 ± 3%, P < 0.05) and nitrite (-34 ± 4%, P < 0.05) during PD, which may result in impairment of the nitrate-nitrite-NO pathway. Indeed, PD was associated with significant reduction of cyclic guanosine monophosphate levels (-59.4 ± 15%, P < 0.05). This reduction in NO signaling was partly prevented by using a commercially available PD solution supplemented with l-arginine. Although PD compromised nitrate-nitrite-NO signaling in all cases, only infants with persistently low SBP developed ischemic cerebral complications. Conclusions Our data suggests that PD impairs NO homeostasis and predisposes infants with persistently low SBP to cerebral ischemia. These findings improve current understanding of the pathogenesis of infantile cerebral ischemia induced by PD and may lead to the new treatment strategies to reduce neurological morbidities.
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22. |
- Carlström, Mattias, et al.
(author)
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Relief of chronic partial ureteral obstruction attenuates salt-sensitive hypertension in rats
- 2007
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In: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 189:1, s. 67-75
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Journal article (peer-reviewed)abstract
- Aim: The incidence of hydronephrosis due to ureteropelvic junction obstruction is approx. 0.5%. During the last decade, the management of non-symptomatic hydronephrosis has become much more conservative, but the long-term physiological consequences of this policy are not clear. Previously, we have shown that animals with chronic partial unilateral ureteral obstruction develop salt-sensitive hypertension. In this study, the effects of ipsilateral and contralateral nephrectomy and ureterovesicostomy on blood pressure were studied in hydronephrotic animals. Methods: Partial unilateral ureteral obstruction was created in 3-week-old male Sprague–Dawley rats and blood pressure was measured telemetrically 4–6 weeks later during a normal and high salt diet before and after uninephrectomy or ureterovesicostomy. Plasma samples for renin assay were collected during both diets before and after ipsilateral nephrectomy. Results: All hydronephrotic animals developed salt-sensitive hypertension, of different degrees. Before nephrectomy the plasma renin concentration was significantly higher in the hydronephrotic animals than in controls (160 ± 15 μGU mL−1 vs. 96 ± 12 μGU mL−1, respectively), but after the ipsilateral nephrectomy no differences were found between the groups. In the hydronephrotic animals both ipsilateral nephrectomy and ureterovesicostomy reduced the blood pressure and salt-sensitivity but the former still differed significantly from the controls. In contralaterally, nephrectomized hydronephrotic animals the salt-sensitive hypertension became more pronounced. Conclusion: Hydronephrosis in rats causes salt-sensitive hypertension that can be markedly reduced by removing the hydronephrotic kidney or relieving the obstruction by ureterovesicostomy. The mechanisms appear to be intrarenal and primarily located in the diseased kidney, but a secondary mechanism is also present.
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23. |
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24. |
- Carlström, Mattias, et al.
(author)
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Role of nitric oxide deficiency in the development of hypertension in hydronephrotic animals
- 2008
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In: American Journal of Physiology - Renal Physiology. - : American Physiological Society. - 0363-6127 .- 1522-1466 .- 1931-857X. ; 294:2, s. 362-370
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Journal article (peer-reviewed)abstract
- Hydronephrotic animals develop renal injury and hypertension, which is associated with an abnormal tubuloglomerular feedback (TGF). The TGF sensitivity is coupled to nitric oxide (NO) in the macula densa. The involvement of reduced NO availability in the development of hypertension in hydronephrosis was investigated. Hydronephrosis was induced by ureteral obstruction in young rats. Blood pressure and renal excretion were measured in adulthood, under different sodium conditions, and before and after chronic administration of either N-G- nitro-L-arginine methyl ester (L-NAME) or L-arginine. Blood samples for ADMA, SDMA, and L-arginine analysis were taken and the renal tissue was used for histology and determination of NO synthase (NOS) proteins. TGF characteristics were determined by stop-flow pressure technique before and after administration of 7-nitroindazole (7-NI) or L-arginine. Hydronephrotic animals developed salt-sensitive hypertension, which was associated with pressure natriuresis and diuresis. The blood pressure response to L-NAME was attenuated and L-arginine supplementation decreased blood pressure in hydronephrotic animals, but not in the controls. Under control conditions, reactivity and sensitivity of the TGF response were greater in the hydronephrotic group. 7-NI administration increased TGF reactivity and sensitivity in control animals, whereas, in hydronephrotic animals, neuronal NOS (nNOS) inhibition had no effect. L-Arginine attenuated TGF response more in hydronephrotic kidneys than in controls. The hydronephrotic animals displayed various degrees of histopathological changes. ADMA and SDMA levels were higher and the renal expressions of nNOS and endothelial NOS proteins were lower in animals with hydronephrosis. Reduced NO availability in the diseased kidney in hydronephrosis, and subsequent resetting of the TGF mechanism, plays an important role in the development of hypertension.
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25. |
- Carlström, Mattias, et al.
(author)
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Role of NOX2 in the regulation of afferent arteriole responsiveness
- 2009
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In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 296:1, s. R72-R79
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Journal article (peer-reviewed)abstract
- NADPH oxidases (NOX) are the major source of reactive oxygen species (ROS) in the vasculature and contribute to the control of renal perfusion. The role of NOX2 in the regulation of blood pressure and afferent arteriole responsiveness was investigated in NOX2(-/-) and wild-type mice. Arteriole constrictions to ANG II (10(-14)-10(-6) mol/l) were weaker in NOX2(-/-) compared with wild types. N(omega)-nitro-l-arginine methyl ester (l-NAME; 10(-4) mol/l) treatment reduced basal diameters significantly more in NOX2(-/-) (-18%) than in wild types (-6%) and augmented ANG II responses. Adenosine (10(-11)-10(-4) mol/l) constricted arterioles of wild types but not of NOX2(-/-). However, simultaneous inhibition of adenosine type-2 receptors induced vasoconstriction, which was stronger in NOX2(-/-). Adenosine (10(-8) mol/l) enhanced the ANG II response in wild type, but not in NOX2(-/-). This sensitizing effect by adenosine was abolished by apocynin. Chronic ANG II pretreatment (14 days) did not change the ANG II responses in NOX2(-/-), but strengthened the response in wild types. ANG II pretreatment augmented the l-NAME response in NOX2(-/-) (-33%), but not in wild types. Simultaneous application of l-NAME and ANG II caused a stronger constriction in the NOX2(-/-) (-64%) than in wild types (-46%). Basal blood pressures were similar in both genotypes, however, chronic ANG II infusion elevated blood pressure to a greater extent in wild-type (15 +/- 1%) than in NOX2(-/-) (8 +/- 1%) mice. In conclusion, NOX2 plays an important role in the control of afferent arteriole tone and is involved in the contractile responses to ANG II and/or adenosine. NOX2 can be activated by elevated ANG II and may play an important role in ANG II-induced hypertension. NOX2-derived ROS scavenges nitric oxide, causing subsequent nitric oxide-deficiency.
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26. |
- Carlström, Mattias, et al.
(author)
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SOD1-Deficiency Causes Salt-Sensitivity and Aggravates Hypertension in Hydronephrosis
- 2009
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In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 297:1, s. R82-R92
-
Journal article (peer-reviewed)abstract
- Background: Hydronephrosis causes renal dysfunction and salt-sensitive hypertension, which is associated with NO-deficiency and abnormal tubuloglomerular feedback (TGF) response. We investigated the role of oxidative stress for salt-sensitivity and for hypertension in hydronephrosis. Methods: Hydronephrosis was induced in SOD1-transgenic (SOD1-tg), SOD1-deficient (SOD1-ko) and wild-type mice and in rats. In mice, telemetric measurements were performed during normal (0.7% NaCl) and high sodium (4% NaCl) diets and with chronic Tempol supplementation. 8-iso-prostaglandin-F2alpha (F2-IsoPs) and protein excretion profiles and histology were investigated. The acute effects of Tempol on blood pressure and TGF were studied in rats. Results: In hydronephrosis, wild-type mice developed salt-sensitive hypertension (114+/-1 to 120+/-2 mmHg) which was augmented in SOD1-ko (125+/-3 to 135+/-4 mmHg), but abolished in SOD1-tg (109+/-3 to 108+/-3 mmHg). SOD1-ko controls displayed salt-sensitive blood pressure (108+/-1 to 115+/-2 mmHg), which was not found in wild-types or SOD1-tg. Chronic Tempol treatment reduced blood pressure in SOD1-ko controls (-7 mmHg) and in hydronephrotic wild-types (-8 mmHg) and SOD1-ko mice (-16 mmHg), but had no effect on blood pressure in wild-type or SOD1-tg controls. SOD1-ko controls and hydronephrotic wild-type and SOD1-ko mice exhibited increased fluid excretion associated with increased F2-IsoPs and protein excretion. The renal histopathological changes found in hydronephrotic wild-types were augmented in SOD1-ko and diminished in SOD-tg mice. Tempol attenuated blood pressure and normalized TGF response in hydronephrosis (DeltaPSF: 15.2+/-1.2 to 9.1+/-0.6 mmHg, TP: 14.3+/-0.8 to 19.7+/-1.4 nl/min). Conclusion: Oxidative stress due to SOD1-deficiency causes salt-sensitivity and plays a pivotal role for the development of hypertension in hydronephrosis. Increased superoxide formation may enhance TGF response and thereby contribute to hypertension.
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27. |
- Carlström, Mattias, et al.
(author)
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Superoxide Dismutase 1 Limits Renal Microvascular Remodeling and Attenuates Arteriole and Blood Pressure Responses to Angiotensin II via Modulation of Nitric Oxide Bioavailability
- 2010
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In: Hypertension. - 0194-911X .- 1524-4563. ; 56:5, s. 907-913
-
Journal article (peer-reviewed)abstract
- Oxidative stress is associated with vascular remodeling and increased preglomerular resistance that are both implicated in the pathogenesis of renal and cardiovascular disease. Angiotensin II induces superoxide production, which is metabolized by superoxide dismutase (SOD) or scavenged by NO. We investigated the hypothesis that SOD1 regulates renal microvascular remodeling, blood pressure, and arteriolar responsiveness and sensitivity to angiotensin II using SOD1-transgenic (SOD1-tg) and SOD1-knockout (SOD1-ko) mice. Blood pressure, measured telemetrically, rose more abruptly during prolonged angiotensin II infusion in SOD1-ko mice. The afferent arteriole media: lumen ratios were reduced in SOD1-tg and increased in SOD1-ko mice. Afferent arterioles from nontreated wild types had graded contraction to angiotensin II (sensitivity: 10(-9) mol/L; responsiveness: 40%). Angiotensin II contractions were less sensitive (10(-8) mol/L) and responsive (14%) in SOD1-tg but more sensitive (10(-13) mol/L) and responsive (89%) in SOD1-ko mice. Arterioles from SOD1-ko had 4-fold increased superoxide formation with angiotensin II at 10(-9) mol/L. N-G-nitro-L-arginine methyl ester reduced arteriole diameter of SOD1-tg and enhanced angiotensin II sensitivity and responsiveness of wild-type and SOD1-tg mice to the level of SOD1-ko mice. SOD mimetic treatment with Tempol increased arteriole diameter and normalized the enhanced sensitivity and responsiveness to angiotensin II of SOD1-ko mice but did not affect wild-type or SOD1-tg mice. Neither SOD1 deficiency nor overexpression was associated with changes in nitrate/nitrite excretion or renal mRNA expression of NO synthase, NADPH oxidase, or SOD2/SOD3 isoforms and angiotensin II receptors. In conclusion, SOD1 limits afferent arteriole remodeling and reduces sensitivity and responsiveness to angiotensin II by reducing superoxide and maintaining NO bioavailability. This may prevent an early and exaggerated blood pressure response to angiotensin II.
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28. |
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29. |
- Carlström, Mattias, et al.
(author)
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Uninephrectomy in Young Age or Chronic Salt Loading Causes Salt-Sensitive Hypertension in Adult Rats
- 2007
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In: Hypertension. - 0194-911X .- 1524-4563. ; 49:6, s. 1342-1350
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Journal article (peer-reviewed)abstract
- The importance of nephron endowment and salt intake for the development of hypertension is under debate. The present study was designed to investigate whether reduced nephron number, after completion of nephrogenesis, or chronic salt loading causes renal injury and salt-sensitive hypertension in adulthood. Rats were operated at 3 weeks of age (after completed nephrogenesis) and then subjected to either normal or high-salt diets for 6 to 8 weeks. Four different experimental groups were used: sham-operated animals raised with normal-salt diet (controls) or high-salt diet (HS) and uninephrectomized animals raised with normal-salt diet (UNX) or high-salt diet (UNX+HS). In the adult animals, renal and cardiovascular functions were evaluated and blood pressure recorded telemetrically under different sodium conditions (normal, high, and low). Hypertension was present in UNX+HS (122±9 mm Hg), UNX (101±3 mm Hg), and HS (96± 1 mm Hg) groups on normal-salt diets compared with the controls (84±2 mm Hg), and the blood pressure was salt sensitive (high- versus normal-salt diet; 23±3, 9±2, 7±2, and 1±1 mm Hg, respectively). The hypertensive groups (UNX+HS, UNX, and HS) had increased diuresis and reduced ability to concentrate urine. The glomerular filtration rate (milliliters per minute) in anesthetized rats was reduced in the UNX+HS (2.36±0.30) and UNX animals (2.00±0.31) compared with both HS animals (3.55±0.45) and controls (3.01±0.35). Hypertensive groups displayed reduced plasma renin concentrations during high sodium conditions and hypertrophic kidneys and hearts with various degrees of histopathologic changes. In conclusion, at a young age after completed nephrogenesis, uninephrectomy or chronic salt loading causes renal and cardiovascular injury with salt-sensitive hypertension.
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30. |
- Carlström, Stefanos, et al.
(author)
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General time-dependent configuration-interaction singles. II. Atomic case
- 2022
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In: Physical Review A. - 2469-9926. ; 106:4
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Journal article (peer-reviewed)abstract
- We present a specialization of the grid-based implementation of the time-dependent configuration-interaction singles described in the preceding paper [S. Carlström et al., preceding paper, Phys. Rev. A 106, 043104 (2022)]10.1103/PhysRevA.106.043104. to the case of spherical symmetry. We describe the intricate time propagator in detail and conclude with a few example calculations. Among these, of note are high-resolution photoelectron spectra in the vicinity of the Fano resonances in photoionization of neon and spin-polarized photoelectrons from xenon, in agreement with recent experiments.
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31. |
- Danielsson, Torkel, et al.
(author)
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A climbing robot for autonomous inspection of live power lines
- 2006
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In: Proceedings of ASER2006 3rd International Workshop on Advances in Service Robots.
-
Conference paper (peer-reviewed)abstract
- Power line inspection is risky and repetitive, thus replacement by a service robot is desirable. A robot for this task, the line inspection robot (LIR), is described. Previous work has been done and our contribution is to decrease complexity in the mechanics of the robot and to structure the control of the robot through reinforcement learning. Two issues need to be addressed in the creation of the LIR. Firstly, the robot needs to traverse a power line mounted on a conductor and pass obstacles on it. Secondly, the LIR needs to detect faults on the power line without help of human operators.
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32. |
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33. |
- Gao, Xiang, et al.
(author)
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Adenosine A(1)-receptor deficiency diminishes afferent arteriolar and blood pressure responses during nitric oxide inhibition and angiotensin II treatment
- 2011
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In: American Journal of Physiology. Regulatory Integrative and Comparative Physiology. - : American Physiological Society. - 0363-6119 .- 1522-1490. ; 301:6, s. R1669-R1681
-
Journal article (peer-reviewed)abstract
- Adenosine mediates tubuloglomerular feedback responses via activation of A(1)-receptors on the renal afferent arteriole. Increased preglomerular reactivity, due to reduced nitric oxide (NO) production or increased levels of ANG II and reactive oxygen species (ROS), has been linked to hypertension. Using A(1)-receptor knockout (A(1)(-/-)) and wild-type (A(1)(+/+)) mice we investigated the hypothesis that A(1)-receptors modulate arteriolar and blood pressure responses during NO synthase (NOS) inhibition or ANG II treatment. Blood pressure and renal afferent arteriolar responses were measured in nontreated mice and in mice with prolonged N(omega)-nitro-L-arginine methyl ester hydrochloride (L-NAME) or ANG II treatment. The hypertensive responses to L-NAME and ANG II were clearly attenuated in A(1)(-/-) mice. Arteriolar contractions to L-NAME (10(-4) mol/l; 15 min) and cumulative ANG II application (10(-12) to 10(-6) mol/l) were lower in A(1)(-/-) mice. Simultaneous treatment with tempol (10(-4) mol/l; 15 min) attenuated arteriolar responses in A(1)(+/+) but not in A(1)(-/-) mice, suggesting differences in ROS formation. Chronic treatment with L-NAME or ANG II did not alter arteriolar responses in A(1)(-/-) mice, but enhanced maximal contractions in A(1)(+/+) mice. In addition, chronic treatments were associated with higher plasma levels of dimethylarginines (asymmetrical and symmetrical) and oxidative stress marker malondialdehyde in A(1)(+/+) mice, and gene expression analysis showed reduced upregulation of NOS-isoforms and greater upregulation of NADPH oxidases. In conclusion, adenosine A(1)-receptors enhance preglomerular responses during NO inhibition and ANG II treatment. Interruption of A(1)-receptor signaling blunts L-NAME and ANG II-induced hypertension and oxidative stress and is linked to reduced responsiveness of afferent arterioles.
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34. |
- Gao, Xiang, et al.
(author)
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Adenosine A1 receptor-dependent and independent pathways in modulating renal vascular responses to angiotensin II
- 2015
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In: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 213:1, s. 268-276
-
Journal article (peer-reviewed)abstract
- AIM: Renal afferent arterioles are the effector site for autoregulation of glomerular perfusion and filtration. There is synergistic interaction between angiotensin II (ANG II) and adenosine (Ado) in regulating arteriolar contraction, however, the mechanisms are not clear. In this context, this study investigated the contribution of A1 receptor dependent and independent signaling mechanisms.METHODS: Isolated perfused afferent arterioles from transgenic mice (A1+/+ and A1-/-) were used for vascular reactivity studies. Cultured vascular smooth muscle cells (VSMC) were used for phosphorylation studies of signaling proteins that induce arteriolar contraction.RESULTS: Maximal arteriolar contraction to ANG II was attenuated in A1-/- (22%) compared with A1+/+ (40%). Simultaneous incubation with low dose Ado (10-8 mol/L) enhanced ANG II-induced contraction in A1+/+ (58%), but also in A1-/- (42%). An Ado transporter inhibitor (NBTI) abolished this synergistic effect in A1-/-, but not in wild-type mice. Incubation with Ado+ANG II increased p38 phosphorylation in aortic VSMC from both genotypes, but treatment with NBTI only blocked phosphorylation in A1-/-. Combination of ANG II+Ado also increased MLC phosphorylation in A1+/+ but not significantly in A1-/-, and NBTI had no effects. In agreement, Ado+ANG II-induced phosphorylation of p38 and MLC in rat preglomerular VSMC was not affected by NBTI. However, during pharmacological inhibition of the A1 receptor simultaneous treatment with NBTI reduced phosphorylation of both p38 and MLC to control levels.CONCLUSION: Interaction between ANG II and Ado in VSMC normally involves A1 receptor signaling, but this can be compensated by receptor independent actions that phosphorylate p38 MAPK and MLC.
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37. |
- Jakobsson, Jenny, et al.
(author)
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Large differences in testosterone excretion in Korean and Swedish men are strongly associated with a UDP-glucuronosyl transferase 2B17 polymorphism.
- 2006
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In: The Journal of clinical endocrinology and metabolism. - : The Endocrine Society. - 0021-972X .- 1945-7197. ; 91:2, s. 687-93
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Journal article (peer-reviewed)abstract
- CONTEXT: The reproductive endocrinology in Asians and Caucasians is of great interest in view of large differences in prostate cancer rate and sensitivity to pharmacological male contraception. In addition, interpretation of certain antidoping tests is confounded by interethnic variation in androgen disposition. Uridine diphosphoglucuronosyl transferases have a key role in the homeostasis and metabolism of androgens. Recently a deletion polymorphism was detected in the UGT2B17 gene. OBJECTIVE: The objective of the study was to evaluate the contribution of the UGT2B17 deletion polymorphism to the interindividual and interethnic variation of androgen metabolism and excretion. METHODS AND RESULTS: Urine from 122 Swedish and 74 Korean healthy men was analyzed for several androgen glucuronides including testosterone. The distribution of the natural logarithms of urinary testosterone concentrations showed a distinct bimodal pattern in both groups, suggesting a monogenic inheritance. When the UGT2B17 genotypes were compared with urinary testosterone levels, all of the individuals of the UGT2B17 homozygous deletion/deletion genotype had no or negligible amounts of urinary testosterone. The deletion/deletion genotype was seven times more common in the Korean (66.7%) than the Swedish population (9.3%). In addition, the Swedes had significantly higher levels of serum testosterone, compared with the Koreans. CONCLUSIONS: Our results show that the UGT2B17 polymorphism is strongly associated with the bimodal distribution of the testosterone excretion and also with the large differences in testosterone excretion between Koreans and Swedes.
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38. |
- Jeddi, Sajad, et al.
(author)
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Hydrogen sulfide potentiates the protective effects of nitrite against myocardial ischemia-reperfusion injury in type 2 diabetic rats
- 2022
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In: Nitric Oxide - Biology and Chemistry. - : Elsevier BV. - 1089-8603 .- 1089-8611. ; 124, s. 15-23
-
Journal article (peer-reviewed)abstract
- Decreased heart levels of nitric oxide (NO) and hydrogen sulfide (H2S) in type 2 diabetes (T2D) are associated with a higher risk of mortality following ischemia-reperfusion (IR) injury. This study aimed to determine the effects of co-administration of sodium nitrite and sodium hydrosulfide (NaSH) on IR injury in the isolated heart from rats with T2D. Two-month-old male rats were divided into 5 groups (n = 7/group): Control, T2D, T2D + nitrite, T2D + NaSH, and T2D + nitrite + NaSH. T2D was induced using a high-fat diet and a single low dose streptozotocin (30 mg/kg) in intraperitoneal injection. Nitrite (50 mg/L in drinking water) and NaSH (0.28 mg/kg, daily intraperitoneal injection) were administrated for 9 weeks. At the end of the study, hemodynamic parameters were recorded, and infarct size and mRNA expression of H2S- and NO-producing enzymes were measured in the isolated hearts. Nitrite administration to rats with T2D improved recovery of left ventricular developed pressure (LVDP) and the peak rates of positive and negative changes in LV pressure (±dp/dt) by 30%, 17%, and 7.9%, respectively, and decreased infarct size by 18.4%. Co-administration of nitrite and NaSH resulted in further improve in recovery of LVDP, +dp/dt, and –dp/dt by 8.3% (P = 0.0478), 8.4% (P = 0.0085), and 9.0% (P = 0.0004), respectively, and also further decrease in infarct size by 24% (P = 0.0473). Nitrite treatment decreased inducible and neuronal NO synthases (iNOS, 0.4-fold; nNOS, 0.4-fold) and cystathionine β-synthase (CBS, 0.1-fold) expression in the isolated heart from rats with T2D. Co-administration of nitrite and NaSH further increased cystathionine γ-lyase (CSE, 2.8-fold) and endothelial NOS (eNOS, 2.0-fold) expression and further decreased iNOS (0.4-fold) expression. In conclusion, NaSH at a low dose potentiates the favorable effects of inorganic nitrite against myocardial IR injury in a rat model of T2D. These anti-ischemic effects, following co-administration of nitrite and NaSH, were associated with higher CSE-derived H2S and eNOS-derived NO as well as lower iNOS-derived NO in the diabetic hearts.
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39. |
- Jeddi, Sajad, et al.
(author)
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Long-term co-administration of sodium nitrite and sodium hydrosulfide inhibits hepatic gluconeogenesis in male type 2 diabetic rats : Role of PI3K-Akt-eNOS pathway
- 2021
-
In: Life Sciences. - : Elsevier BV. - 0024-3205 .- 1879-0631. ; 265
-
Journal article (peer-reviewed)abstract
- Objective: A deficiency in hydrogen sulfide (H2S) and nitric oxide (NO) contributes to the development of type 2 diabetes (T2D). An inhibitory effect on liver gluconeogenesis has been reported in rats with T2D with co-administration of sodium nitrite and sodium hydrosulfide (NaSH); the underlying mechanisms have however not yet been elucidated. The aim of this study is to determine the long-term effects of co-administering sodium nitrite and NaSH on expression of genes involved in liver gluconeogenesis in rats with T2D. Methods: T2D was induced using a high fat diet combined with low-dose of streptozotocin (30 mg/kg). Rats were divided into 5 groups (n = 7/group): Control, T2D, T2D + nitrite, T2D + NaSH, and T2D + nitrite+NaSH. Nitrite (50 mg/L) and NaSH (0.28 mg/kg) were administered for 9 weeks. Intraperitoneal pyruvate tolerance test (PTT) was performed at the end of the ninth week and mRNA expressions of PI3K, Akt, eNOS, PEPCK, G6Pase, and FBPase were measured in the liver. Results: Co-administration of nitrite and NaSH decreased elevated serum glucose concentrations during PTT. Compared to T2D + nitrite, co-administration of nitrite and NaSH resulted in significant increases in mRNA expression of PI3K, Akt, and eNOS and significant decreases in mRNA expression of G6Pase and FBPase but had no effect on PEPCK expression. Conclusion: Long-term NaSH administration at low-dose, potentiated the inhibitory effects of nitrite on mRNA expression of key liver gluconeogenic enzymes in rats with T2D. This inhibitory effect of nitrite and NaSH co-administration on gluconeogenesis were associated with increased gene expression of PI3K, Akt, and eNOS in the liver.
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40. |
- Jeddi, Sajad, et al.
(author)
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Protective effect of intermediate doses of hydrogen sulfide against myocardial ischemia-reperfusion injury in obese type 2 diabetic rats
- 2020
-
In: Life Sciences. - : Elsevier BV. - 0024-3205 .- 1879-0631. ; 256
-
Journal article (peer-reviewed)abstract
- Objective: Subjects with type 2 diabetes (T2D) have lower circulating hydrogen sulfide (H2S) levels following myocardial ischemia and a higher risk of mortality. The aim of this study was to determine the dose-dependent favorable effects of sodium hydrosulfide (NaSH) on myocardial ischemia-reperfusion (IR) injury in rats with T2D. Methods: T2D was induced using a high-fat diet (HFD) and low-dose of streptozotocin. Rats were divided into control, T2D, and T2D + NaSH groups. NaSH (0.28, 0.56, 1.6, 2.8, and 5.6 mg/kg) was administered intraperitoneally for 9 weeks. At the end of the study, heart from all rats were isolated and left ventricular developed pressure (LVDP) and the peak rates of positive and negative changes in LV pressure (±dp/dt) were recorded during baseline and following myocardial IR injury. In addition, infarct size as well as mRNA expression of H2S- and nitric oxide (NO)-producing enzymes were measured. Results: In diabetic rats, NaSH only at doses of 0.56 and 1.6 mg/kg increased recovery of LVDP (16% and 42%), +dp/dt (25% and 35%) and –dp/dt (23% and 32%) as well as decreased infarct size (44% and 35%). At these doses, NaSH increased expressions of cystathionine γ-lyase (CSE) (440% and 271%) and endothelial NO synthase (eNOS) (232% and 148%) but it decreased the expressions of inducible NOS (iNOS) (55% and 71%). NaSH at 0.28, 2.8 and 5.6 mg/kg had no significant effects on these parameters. Conclusion: NaSH had a bell-shaped cardioprotective effect against myocardial IR injury in rats with T2D. Higher tolerance to IR injury in heart isolated from type 2 diabetic rats treated with intermediate doses of NaSH is associated with higher CSE-derived H2S and eNOS-derived NO as well as lower iNOS-derived NO.
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41. |
- Lai, En Yin, et al.
(author)
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Angiotensin II enhances the afferent arteriolar response to adenosine through increases in cytosolic calcium
- 2009
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In: Acta Physiologica. - : Wiley. - 1748-1708 .- 1748-1716. ; 196:4, s. 435-445
-
Journal article (peer-reviewed)abstract
- Aims: Angiotensin II (Ang II) is a strong renal vasoconstrictor and modulates the tubuloglomerular feedback (TGF). We hypothesized that Ang II at low concentrations enhances the vasoconstrictor effect of adenosine (Ado), the mediator of TGF. Methods: Afferent arterioles of mice were isolated and perfused, and both isotonic contractions and cytosolic calcium transients were measured. Results: Bolus application of Ang II (10(-12) and 10(-10)M) induced negligible vasoconstrictions, while Ang II at 10(-8) M reduced diameters by 35%. Ang II at 10(-12), 10(-10), and 10(-8) M clearly enhanced the arteriolar response to cumulative applications of Ado (10(-11) to 10(-4)M). Ado application increased the cytosolic calcium concentrations in the vascular smooth muscle, which were higher at 10(-5)M than at 10(-8)M. Ang II (10(-11) to 10(-6)M) also induced concentration-dependent calcium transients, which were attenuated by AT(1) receptor inhibition. Simultaneously applied Ang II (10(-10)M) additively enhanced the calcium transients induced by 10(-8) and 10(-5) M Ado. The transients were partly inhibited by AT(1) or A(1) receptor antagonists, but not significantly by A(2) receptor antagonists. Conclusion: A low dose of Ang II enhances Ado-induced constrictions, partly via AT(1) receptor-mediated calcium increase. Ado increases intracellular calcium by acting on A(1) but not A(2) receptors. The potentiating effect of Ang II on Ado-induced arteriolar vasoconstrictions may involve calcium sensitization of the contractile machinery, as Ang II only additively increased cytosolic calcium concentrations, while its effect on the arteriolar constriction was more than additive. The potentiating effect of Ang II might contribute to the resetting of TGF.
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42. |
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43. |
- Lundberg, Jon O., et al.
(author)
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Roles of dietary inorganic nitrate in cardiovascular health and disease
- 2011
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In: Cardiovascular Research. - : Oxford University Press (OUP). - 0008-6363 .- 1755-3245. ; 89:3, s. 525-532
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Research review (peer-reviewed)abstract
- Inorganic nitrate from dietary and endogenous sources is emerging as a substrate for in vivo generation of nitric oxide (NO) and other reactive nitrogen oxides. Dietary amounts of nitrate clearly have robust NO-like effects in humans, including blood pressure reduction, inhibition of platelet aggregation, and vasoprotective activity. In animal models, nitrate protects against ischaemia-reperfusion injuries and several other types of cardiovascular disorders. In addition, nitrate most surprisingly decreases whole body oxygen cost during exercise with preserved or even enhanced maximal performance. Oxidative stress and reduced NO bioavailability are critically linked to development of hypertension and other forms of cardiovascular diseases. Mechanistically, a central target for the effects of nitrate and its reaction products seems to be the mitochondrion and modulation of oxidative stress. All in vivo effects of nitrate are achievable with amounts corresponding to a rich intake of vegetables, which are particularly rich in this anion. A theory is now emerging suggesting nitrate as an active component in vegetables contributing to the beneficial health effects of this food group, including protection against cardiovascular disease and type-2 diabetes.
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44. |
- Manti, Maria, et al.
(author)
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Maternal androgen excess induces cardiac hypertrophy and left ventricular dysfunction in female mice offspring.
- 2020
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In: Cardiovascular research. - : Oxford University Press (OUP). - 1755-3245 .- 0008-6363. ; 116:3, s. 619-632
-
Journal article (peer-reviewed)abstract
- Polycystic ovary syndrome (PCOS) is a common endocrinopathy that is suggested to increase the risk for cardiovascular disease. How PCOS may lead to adverse cardiac outcomes is unclear and here we hypothesized that prenatal exposure to dihydrotestosterone (DHT) and/or maternal obesity in mice induce adverse metabolic and cardiac programming in female offspring that resemble the reproductive features of the syndrome.The maternal obese PCOS phenotype was induced in mice by chronic high-fat-high-sucrose consumption together with prenatal DHT exposure. The prenatally androgenized (PNA) female offspring displayed cardiac hypertrophy during adulthood, an outcome that was not accompanied by aberrant metabolic profile. The expression of key genes involved in cardiac hypertrophy was up-regulated in the PNA offspring, with limited or no impact of maternal obesity. Furthermore, the activity of NADPH oxidase, a major source of reactive oxygen species in the cardiovascular system, was down-regulated in the PNA offspring heart. We next explored for early transcriptional changes in the heart of newly born PNA offspring, which could account for the long-lasting changes observed in adulthood. Neonatal PNA hearts displayed an up-regulation of transcription factors involved in cardiac hypertrophic remodelling and of the calcium-handling gene, Slc8a2. Finally, to determine the specific role of androgens in cardiovascular function, female mice were continuously exposed to DHT from pre-puberty to adulthood, with or without the antiandrogen flutamide. Continuous exposure to DHT led to adverse left ventricular remodelling, and increased vasocontractile responses, while treatment with flutamide partly alleviated these effects.Taken together, our results indicate that intrauterine androgen exposure programmes long-lasting heart remodelling in female mouse offspring that is linked to left ventricular hypertrophy and highlight the potential risk of developing cardiac dysfunction in daughters of mothers with PCOS.
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45. |
- Marcondes, Rodrigo R., et al.
(author)
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Exercise differentially affects metabolic functions and white adipose tissue in female letrozole-and dihydrotestosterone-induced mouse models of polycystic ovary syndrome
- 2017
-
In: Molecular and Cellular Endocrinology. - : Elsevier. - 0303-7207 .- 1872-8057. ; 448, s. 66-76
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Journal article (peer-reviewed)abstract
- Here we hypothesized that exercise in dihydrotestosterone (DHT) or letrozole (LET)-induced polycystic ovary syndrome mouse models improves impaired insulin and glucose metabolism, adipose tissue morphology, and expression of genes related to adipogenesis, lipid metabolism, Notch pathway and browning in inguinal and mesenteric fat. DHT-exposed mice had increased body weight, increased number of large mesenteric adipocytes. LET-exposed mice displayed increased body weight and fat mass, decreased insulin sensitivity, increased frequency of small adipocytes and increased expression of genes related to lipolysis in mesenteric fat. In both models, exercise decreased fat mass and inguinal and mesenteric adipose tissue expression of Notch pathway genes, and restored altered mesenteric adipocytes morphology. In conclusion, exercise restored mesenteric adipocytes morphology in DHT- and LET-exposed mice, and insulin sensitivity and mesenteric expression of lipolysis-related genes in LET-exposed mice. Benefits could be explained by downregulation of Notch, and modulation of browning and lipolysis pathways in the adipose tissue.
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46. |
- Moksnes, Per-Olav, et al.
(author)
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Fritidsbåtars påverkan på grunda kustekosystem i sverige
- 2019
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Reports (other academic/artistic)abstract
- Sveriges natursköna kust med vidsträckta skärgårdar erbjuder fantastiska förhållanden för fritidsbåtliv. Idag finns uppskattningsvis mer än 700 000 fritidsbåtar i Sverige, vilket är en av de högsta siffrorna i världen sett till befolkningsmängden. Kustens vågskyddade skärgård ger också goda förutsättningar att förvara fritidsbåtar vid bryggor, och idag täcks stora områden av bryggor och småbåtshamnar. Det stora antalet båtar och bryggor kan ge betydande effekter på miljön, men kunskapen om fritidsbåtlivets sammanlagda påverkan på Sveriges kustmiljöer har hittills varit bristfällig. Havsmiljöinstitutets mål med denna rapport har varit att sammanställa kunskapsläget kring hur fritidsbåtar påverkar grunda kustekosystem i Sverige, samt bedöma omfattningen av denna påverkan och om utveckling är hållbar. Syftet med rapporten är att bidra till utvecklingen av en mer hållbar förvaltning av fritidsbåtlivet genom att sammanställa vetenskaplig kunskap inom detta område på ett lättillgängligt sätt. Sammanställningen visar att det finns ett starkt stöd i den vetenskapliga litteraturen för att fritidsbåtar ger upphov till många negativa effekter på kustmiljön. Med fritidsbåtslivet följer en rad olika fysiska strukturer och aktiviteter som var och en ger upphov till flera olika typer av miljöpåverkan. En ökad utbredning av småbåtshamnar, bryggor och muddrade områden medför förluster av viktiga bottenmiljöer och leder ofta till en långvarig försämring av miljöförhållanden lokalt. Muddrings- och dumpningsaktiviteter leder till ökad uppgrumling och spridning av sediment, näringsämnen och miljögifter över stora områden, vilket bland annat påverkar bottenvegetation, fiskar och musslor negativt. Båttrafik och ankring leder till uppgrumling och erosion av sediment samt till skador på bottenmiljön. Undervattensbuller från båtarnas motorer stör också fiskar och däggdjur. Vidare medför användning av fritidsbåtar betydande utsläpp av giftiga ämnen och föroreningar från båtbottenfärger och förbränningsmotorer. Drygt 60 % av alla bryggor och småbåtshamnar återfinns i grunda (<3 m), vågskyddade områden med mjukbottnar, trots att de endast utgör en fjärdedel av kustens totala grundområden. Dessa områden lämpar sig väl för båtförvaring, men är också en av kustens mest produktiva och värdefulla miljöer. Grunda mjukbottnar är en viktig miljö för olika kärlväxter och kransalger, som i sin tur utgör viktiga uppväxthabitat för många olika fiskarter och kräftdjur. Rapporten visar att dessa miljöer är extra känsliga för en majoritet av de störningar som fritidsbåtlivet ger upphov till. Sammantaget medför detta att fritidsbåtslivet i förhållande till sin omfattning genererar stora skador på miljöer med höga naturvärden.
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47. |
- Moksnes, Per-Olav, et al.
(author)
-
Fritidsbåtars påverkan på grunda kustekosystem i Sverige
- 2019
-
Reports (other academic/artistic)abstract
- Sweden has a long and beautiful coastline with extensive archipelagos that offer exceptional conditions for recreational boating. There are more than 700 000 recreational boats in Sweden, which is one of the highest numbers in the world in relation to the population size. Small tidal differences and many sheltered bays also provide good conditions for storing boats at docks and piers and jetties. As a result, large areas of the Swedish coast are today covered with docks and marinas for recreational boats. The large number of boats and docks could have substantial negative effects on the environment. However, the understanding of the cumulative impact of recreational boating on Swedish coastal ecosystem has so far been incomplete. The goal with this report from the Swedish Institute for the Marine Environment has been to compile and summarize the present state of knowledge regarding how recreational boating affect shallow coastal ecosystems in Sweden, to determine the extent of the impact and if the development is sustainable. The aim has been to present scientific knowledge on these topics in an accessible way in order to facilitate the development of a more sustainable management of recreational boating in Sweden.The scientific literature strongly support that recreational boating generates many negative effects on the marine environment. Recreational boating requires a number of physical structures and generate a number activities that each results in several different pressures on the environment. An increased number of marinas, docks and dredged canals results in losses of important habitats, as well as long-term deterioration of the environmental conditions locally. Dredging and dumping of dredge material results in increased turbidity and dispersal of sediment, nutrients and pollutants over large areas with negative effects on many aquatic organisms, e.g. vegetation, fishes and mussels. Traffic from recreational boats and anchoring result in increased turbidity and sediment erosion as well as damage to habitats. Motor boats also create underwater noise that can disturb e.g. fishes, seals and porpoises. In addition, recreational boating result in substantial emissions of toxic substances and pollution from e.g. antifouling paint and combustion engines.More than 60% of all docks and marinas are found in wave sheltered, shallow (<3 m) areas with soft bottoms, despite that this environment only constitute 25% of shallow coastal areas in Sweden. These sheltered areas are well suited for storing boats, but also constitute one of the most productive and valuable environments along the coast. They are important environments for vegetation such as seagrass, pondweed and stoneworts, which in turn constitute important spawning and nursery areas for a large number of fish and invertebrates. The report shows that these shallow soft bottom environments are very sensitive to a majority of the stressors that recreational boating generate. Boating therefore create a disproportionally large impact on environments with high values.Although the impact from a single recreational boat or dock is limited, the cumulative effect is substantial because of the sheer number. According to recent inventories, there are today almost 110 000 docks along the Swedish coast covering almost 2 000 km of bottom. In comparison with the 1960s, the amount of docks has increased with almost 160%, which today constitutes an increase of 1 700 new docks per year. Recent studies show that vegetation is degraded as the number of docks and boats increase within shallow, wave sheltered areas. It is estimated that almost 20% of this important environment is negatively affected by recreational boating today; in the County of Stockholm and Västra Götaland around 30% of shallow, wave sheltered areas are estimated to be impacted. Despite several management measures in the last decades to decrease coastal exploitation, there are no signs that the rate of exploitation is decreasing.The large number of recreational boats with combustion engines, the trend of increasing engine size, and the fact that engines lack all forms of emission control result in substantial emissions of pollutants and greenhouse gases. Recent estimates suggest that the emissions from recreational boats are very high and comparable with other types of transport in Sweden. Emission of toxic copper from antifouling paint on recreational boats is also substantial and contributes to the high levels of copper in coastal waters, which is above the limit for good ecological status in 85% of the assessed coastal water bodies.Although most boat owners likely spend time at sea because they enjoy and care about the environment, the results presented in this report show that recreational boating have a substantial negative impact on the coastal environment, particularly in shallow, wave protected areas. In these areas, today’s use and development of recreational boating cannot be considered sustainable. However, the report also shows that there are ways to decrease the environmental impact from recreational boating. By changing the way we use and store recreational boats, and by improving management we can still allow coming generations to enjoy unexploited coastal environments with clear water and a rich plant and animal life.The report ends by discussing new, possible measures and solutions for a more sustainable use of recreational boats in Sweden, which could be a starting point for continuing such work. These include e.g. to identify vulnerable coastal environments in order to steer away exploitation and recreational boat traffic from these areas. By storing boats on land, the need for docks, dredging and toxic antifouling paint could decrease. Reduced speed limits and access limitations for recreational motorboats in certain areas could decrease negative impact on the most vulnerable habitats. Finally, new, environmentally friendly technology, and new financial instruments could be used to decrease negative impacts and create a more sustainable development of recreational boating.
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48. |
- Montenegro, Marcelo F, et al.
(author)
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Blood Pressure-Lowering Effect of Orally Ingested Nitrite Is Abolished by a Proton Pump Inhibitor.
- 2017
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In: Hypertension. - 0194-911X .- 1524-4563. ; 69:1, s. 23-31
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Journal article (peer-reviewed)abstract
- Inorganic nitrate and nitrite from dietary and endogenous sources are metabolized to NO and other bioactive nitrogen oxides that affect blood pressure. The mechanisms for nitrite bioactivation are unclear, but recent studies in rodents suggest that gastric acidity may influence the systemic effects of this anion. In a randomized, double-blind, placebo-controlled crossover study, we tested the effects of a proton pump inhibitor on the acute cardiovascular effects of nitrite. Fifteen healthy nonsmoking, normotensive subjects, aged 19 to 39 years, were pretreated with placebo or esomeprazole (3×40 mg) before ingesting sodium nitrite (0.3 mg kg(-1)), followed by blood pressure monitoring. Nitrite reduced systolic blood pressure by a maximum of 6±1.3 mm Hg when taken after placebo, whereas pretreatment with esomeprazole blunted this effect. Peak plasma nitrite, nitrate, and nitroso species levels after nitrite ingestion were similar in both interventions. In 8 healthy volunteers, we then infused increasing doses of sodium nitrite (1, 10, and 30 nmol kg(-1) min(-1)) intravenously. Interestingly, although plasma nitrite peaked at similar levels as with orally ingested nitrite (≈1.8 µmol/L), no changes in blood pressure were observed. In rodents, esomeprazole did not affect the blood pressure response to the NO donor, DEA NONOate, or vascular relaxation to nitroprusside and acetylcholine, demonstrating an intact downstream NO-signaling pathway. We conclude that the acute blood pressure-lowering effect of nitrite requires an acidic gastric environment. Future studies will reveal if the cardiovascular complications associated with the use of proton pump inhibitors are linked to interference with the nitrate-nitrite-NO pathway.
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49. |
- Moretti, Chiara H., et al.
(author)
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Dietary nitrite extends lifespan and prevents age-related locomotor decline in the fruit fly
- 2020
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In: Free Radical Biology & Medicine. - : Elsevier BV. - 0891-5849 .- 1873-4596. ; 160, s. 860-870
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Journal article (peer-reviewed)abstract
- Aging is associated with decreased nitric oxide (NO) bioavailability and signalling. Boosting of a dietary nitrate nitrite-NO pathway e.g. by ingestion of leafy green vegetables, improves cardiometabolic function, mitochondrial efficiency and reduces oxidative stress in humans and rodents, making dietary nitrate and nitrite an appealing intervention to address age-related disorders. On the other hand, these anions have long been implicated in detrimental health effects of our diet, particularly in formation of carcinogenic nitrosamines.The aim of this study was to assess whether inorganic nitrite affects lifespan in Drosophila melanogaster and investigate possible mechanisms underlying any such effect.In a survival assay, female flies fed a nitrite supplemented diet showed lifespan extension by 9 and 15% with 0.1 and 1 mu M nitrite respectively, with no impact of nitrite on reproductive output. Interestingly, nitrite could also protect female flies from age-dependent locomotor decline, indicating a protective effect on healthspan. NO generation from nitrite involved Drosophila commensal bacteria and was indicated by a fluorescent probe as well as direct measurements of NO gas formation with chemiluminescence.Nutrient sensing pathways such as TOR and sirtuins, have been strongly implicated in lifespan extension. In aged flies, nitrite supplementation significantly downregulated dTOR and upregulated dSir2 gene expression. Total triglycerides and glucose were decreased, a described downstream effect of both TOR and sirtuin pathways.In conclusion, we demonstrate that very low doses of dietary nitrite extend lifespan and favour healthspan in female flies. We propose modulation of nutrient sensing pathways as driving mechanisms for such effects.
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50. |
- Nandi, Saikat, et al.
(author)
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Generation of entanglement using a short-wavelength seeded free-electron laser
- 2024
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In: SCIENCE ADVANCES. - 2375-2548. ; 10:16
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Journal article (peer-reviewed)abstract
- Quantum entanglement between the degrees of freedom encountered in the classical world is challenging to observe due to the surrounding environment. To elucidate this issue, we investigate the entanglement generated over ultrafast timescales in a bipartite quantum system comprising two massive particles: a free-moving photoelectron, which expands to a mesoscopic length scale, and a light-dressed atomic ion, which represents a hybrid state of light and matter. Although the photoelectron spectra are measured classically, the entanglement allows us to reveal information about the dressed-state dynamics of the ion and the femtosecond extreme ultraviolet pulses delivered by a seeded free-electron laser. The observed generation of entanglement is interpreted using the time-dependent von Neumann entropy. Our results unveil the potential for using short-wavelength coherent light pulses from free-electron lasers to generate entangled photoelectron and ion systems for studying spooky action at a distance.
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