| 1. |
- Sällström, Johan, et al.
(författare)
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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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Ingår i: 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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Tidskriftsartikel (refereegranskat)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.
(författare)
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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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Ingår i: Pediatric nephrology (Berlin, West). - : Springer. - 0931-041X .- 1432-198X. ; 33:4, s. 639-649
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Tidskriftsartikel (refereegranskat)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
(författare)
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High Blood Pressure in Children with Hydronephrosis
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)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.
(författare)
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Thomas-Reiche-Kuhn correction for truncated configuration-interaction spaces : Case of laser-assisted dynamical interference
- 2022
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Ingår i: Physical Review A: covering atomic, molecular, and optical physics and quantum information. - 2469-9926 .- 2469-9934. ; 106:4
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Effect of nitric oxide on renal autoregulation during hypothermia in the rat.
- 2017
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Ingår i: Pflügers Archiv. - : Springer Science and Business Media LLC. - 0031-6768 .- 1432-2013. ; 469:5-6, s. 669-680
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Tubuloglomerular feedback response in the prenatal and postnatal ovine kidney
- 2011
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Ingår i: American Journal of Physiology - Renal Physiology. - : American Physiological Society. - 0363-6127 .- 1522-1466 .- 1931-857X. ; 300:6, s. F1368-F1374
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Tidskriftsartikel (refereegranskat)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.
(författare)
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Angiogenesis inhibition causes hypertension and placental dysfunction in a rat model of preeclampsia
- 2009
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Ingår i: Journal of Hypertension. - 0263-6352 .- 1473-5598. ; 27:4, s. 829-837
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Tidskriftsartikel (refereegranskat)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
(författare)
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Causal link between neonatal hydronephrosis and later development of hypertension
- 2010
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Ingår i: Clinical and experimental pharmacology & physiology. - : Wiley. - 0305-1870 .- 1440-1681. ; 37:2, s. E14-E23
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Tidskriftsartikel (refereegranskat)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.
(författare)
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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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Ingår i: Nutrition reviews. - : Oxford University Press (OUP). - 0029-6643 .- 1753-4887. ; 76:6, s. 395-417
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Tidskriftsartikel (refereegranskat)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.
(författare)
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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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Ingår i: Antioxidants and Redox Signaling. - : Mary Ann Liebert Inc. - 1523-0864 .- 1557-7716. ; 23:4, s. 295-306
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Tidskriftsartikel (refereegranskat)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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