| 1. |
- Ehinger, Johannes K., et al.
(författare)
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Cell-permeable succinate prodrugs bypass mitochondrial complex i deficiency
- 2016
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Mitochondrial complex I (CI) deficiency is the most prevalent defect in the respiratory chain in paediatric mitochondrial disease. This heterogeneous group of diseases includes serious or fatal neurological presentations such as Leigh syndrome and there are very limited evidence-based treatment options available. Here we describe that cell membrane-permeable prodrugs of the complex II substrate succinate increase ATP-linked mitochondrial respiration in CI-deficient human blood cells, fibroblasts and heart fibres. Lactate accumulation in platelets due to rotenone-induced CI inhibition is reversed and rotenone-induced increase in lactate:pyruvate ratio in white blood cells is alleviated. Metabolomic analyses demonstrate delivery and metabolism of [ 13 C]succinate. In Leigh syndrome patient fibroblasts, with a recessive NDUFS2 mutation, respiration and spare respiratory capacity are increased by prodrug administration. We conclude that prodrug-delivered succinate bypasses CI and supports electron transport, membrane potential and ATP production. This strategy offers a potential future therapy for metabolic decompensation due to mitochondrial CI dysfunction.
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| 2. |
- Magnusson, Maria K, 1972, et al.
(författare)
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Macrophage and dendritic cell subsets in IBD: ALDH cells are reduced in colon tissue of patients with ulcerative colitis regardless of inflammation
- 2016
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Ingår i: Mucosal Immunology. - : Elsevier BV. - 1935-3456 .- 1935-3456 .- 1933-0219. ; 9:1, s. 171-182
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Tidskriftsartikel (refereegranskat)abstract
- Disruption of the homeostatic balance of intestinal dendritic cells (DCs) and macrophages (MQs) may contribute to inflammatory bowel disease. We characterized DC and MQ populations, including their ability to produce retinoic acid, in clinical material encompassing Crohn's ileitis, Crohn's colitis and ulcerative colitis (UC) as well as mesenteric lymph nodes (MLNs) draining these sites. Increased CD14+DRint MQs characterized inflamed intestinal mucosa while total CD141+ or CD1c+ DCs numbers were unchanged. However, CD103+ DCs, including CD141+CD103+ and CD1c+CD103+ DCs, were reduced in inflamed intestine. In MLNs, two CD14- DC populations were identified: CD11cintHLADRhi and CD11chiHLADRint cells. A marked increase of CD11chiHLADRint DC, particularly DRintCD1c+ DCs, characterized MLNs draining inflamed intestine. The fraction of DC and MQ populations expressing aldehyde dehydrogenase (ALDH) activity, reflecting retinoic acid synthesis, in UC colon, both in active disease and remission, were reduced compared to controls and inflamed Crohn's colon. In contrast, no difference in the frequency of ALDH+ cells among blood precursors was detected between UC patients and non-inflamed controls. This suggests that ALDH activity in myeloid cells in the colon of UC patients, regardless of whether the disease is active or in remission, is influenced by the intestinal environment.
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| 3. |
- Schjørring, O. L., et al.
(författare)
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Intensive care doctors’ preferences for arterial oxygen tension levels in mechanically ventilated patients
- 2018
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Ingår i: Acta Anaesthesiologica Scandinavica. - : Wiley. - 0001-5172 .- 1399-6576. ; 62:10, s. 1443-1451
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Tidskriftsartikel (refereegranskat)abstract
- Background: Oxygen is liberally administered in intensive care units (ICUs). Nevertheless, ICU doctors’ preferences for supplementing oxygen are inadequately described. The aim was to identify ICU doctors’ preferences for arterial oxygenation levels in mechanically ventilated adult ICU patients. Methods: In April to August 2016, an online multiple-choice 17-part-questionnaire was distributed to 1080 ICU doctors in seven Northern European countries. Repeated reminder e-mails were sent. The study ended in October 2016. Results: The response rate was 63%. When evaluating oxygenation 52% of respondents rated arterial oxygen tension (PaO2) the most important parameter; 24% a combination of PaO2 and arterial oxygen saturation (SaO2); and 23% preferred SaO2. Increasing, decreasing or not changing a default fraction of inspired oxygen of 0.50 showed preferences for a PaO2 around 8 kPa in patients with chronic obstructive pulmonary disease, a PaO2 around 10 kPa in patients with healthy lungs, acute respiratory distress syndrome or sepsis, and a PaO2 around 12 kPa in patients with cardiac or cerebral ischaemia. Eighty per cent would accept a PaO2 of 8 kPa or lower and 77% would accept a PaO2 of 12 kPa or higher in a clinical trial of oxygenation targets. Conclusion: Intensive care unit doctors preferred PaO2 to SaO2 in monitoring oxygen treatment when peripheral oxygen saturation was not included in the question. The identification of PaO2 as the preferred target and the thorough clarification of preferences are important when ascertaining optimal oxygenation targets. In particular when designing future clinical trials of higher vs lower oxygenation targets in ICU patients.
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| 4. |
- Ferguson, Michael A, et al.
(författare)
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Increased platelet mitochondrial respiration after cardiac arrest and resuscitation as a potential peripheral biosignature of cerebral bioenergetic dysfunction
- 2016
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Ingår i: Journal of Bioenergetics and Biomembranes. - : Springer Science and Business Media LLC. - 1573-6881 .- 0145-479X. ; 48:3, s. 269-279
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Tidskriftsartikel (refereegranskat)abstract
- Cardiac arrest (CA) results in a sepsis-like syndrome with activation of the innate immune system and increased mitochondrial bioenergetics.OBJECTIVE: To determine if platelet mitochondrial respiration increases following CA in a porcine pediatric model of asphyxia-associated ventricular fibrillation (VF) CA, and if this readily obtained biomarker is associated with decreased brain mitochondrial respiration. CA protocol: 7 min of asphyxia, followed by VF, protocolized titration of compression depth to systolic blood pressure of 90 mmHg and vasopressor administration to a coronary perfusion pressure greater than 20 mmHg.PRIMARY OUTCOME: platelet integrated mitochondrial electron transport system (ETS) function evaluated pre- and post-CA/ROSC four hours after return of spontaneous circulation (ROSC). Secondary outcome: correlation of platelet mitochondrial bioenergetics to cerebral bioenergetic function. Platelet maximal oxidative phosphorylation (OXPHOSCI+CII), P < 0.02, and maximal respiratory capacity (ETSCI+CII), P < 0.04, were both significantly increased compared to pre-arrest values. This was primarily due to a significant increase in succinate-supported respiration through Complex II (OXPHOSCII, P < 0.02 and ETSCII, P < 0.03). Higher respiration was not due to uncoupling, as the LEAKCI + CII respiration (mitochondrial respiration independent of ATP-production) was unchanged after CA/ROSC. Larger increases in platelet mitochondrial respiratory control ratio (RCR) compared to pre-CA RCR were significantly correlated with lower RCRs in the cortex (P < 0.03) and hippocampus (P < 0.04) compared to sham respiration. Platelet mitochondrial respiration is significantly increased four hours after ROSC. Future studies will identify mechanistic relationships between this serum biomarker and altered cerebral bioenergetics function following cardiac arrest.
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| 5. |
- Gustafsson, Jenny K, 1981, et al.
(författare)
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Carbachol-induced colonic mucus formation requires transport via NKCC1, K(+) channels and CFTR.
- 2015
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Ingår i: Pflugers Archiv : European journal of physiology. - : Springer Science and Business Media LLC. - 1432-2013 .- 0031-6768. ; 467:7, s. 1403-1415
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Tidskriftsartikel (refereegranskat)abstract
- The colonic mucosa protects itself from the luminal content by secreting mucus that keeps the bacteria at a distance from the epithelium. For this barrier to be effective, the mucus has to be constantly replenished which involves exocytosis and expansion of the secreted mucins. Mechanisms involved in regulation of mucus exocytosis and expansion are poorly understood, and the aim of this study was to investigate whether epithelial anion secretion regulates mucus formation in the colon. The muscarinic agonist carbachol was used to induce parallel secretion of anions and mucus, and by using established inhibitors of ion transport, we studied how inhibition of epithelial transport affected mucus formation in mouse colon. Anion secretion and mucin exocytosis were measured by changes in membrane current and epithelial capacitance, respectively. Mucus thickness measurements were used to determine the carbachol effect on mucus growth. The results showed that the carbachol-induced increase in membrane current was dependent on NKCC1 co-transport, basolateral K(+) channels and Cftr activity. In contrast, the carbachol-induced increase in capacitance was partially dependent on NKCC1 and K(+) channel activity, but did not require Cftr activity. Carbachol also induced an increase in mucus thickness that was inhibited by the NKCC1 blocker bumetanide. However, mice that lacked a functional Cftr channel did not respond to carbachol with an increase in mucus thickness, suggesting that carbachol-induced mucin expansion requires Cftr channel activity. In conclusion, these findings suggest that colonic epithelial transport regulates mucus formation by affecting both exocytosis and expansion of the mucin molecules.
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| 6. |
- Karlsson, Michael, et al.
(författare)
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Changes in energy metabolism due to acute rotenone-induced mitochondrial complex I dysfunction – An in vivo large animal model
- 2016
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Ingår i: Mitochondrion. - : Elsevier BV. - 1567-7249. ; 31, s. 56-62
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Tidskriftsartikel (refereegranskat)abstract
- Metabolic crisis is a clinical condition primarily affecting patients with inherent mitochondrial dysfunction in situations of augmented energy demand. To model this, ten pigs received an infusion of rotenone, a mitochondrial complex I inhibitor, or vehicle. Clinical parameters, blood gases, continuous indirect calorimetry, in vivo muscle oxygen tension, ex vivo mitochondrial respiration and metabolomics were assessed. Rotenone induced a progressive increase in blood lactate which was paralleled by an increase in oxygen tension in venous blood and skeletal muscle. There was an initial decrease in whole body oxygen utilization, and there was a trend towards inhibited mitochondrial respiration in platelets. While levels of succinate were decreased, other intermediates of glycolysis and the TCA cycle were increased. This model may be suited for evaluating pharmaceutical interventions aimed at counteracting metabolic changes due to complex I dysfunction.
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| 7. |
- Lindgren, Johan, et al.
(författare)
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Skin pigmentation provides evidence of convergent melanism in extinct marine reptiles.
- 2014
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 506:7489, s. 484-484
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Tidskriftsartikel (refereegranskat)abstract
- Throughout the animal kingdom, adaptive colouration serves critical functions ranging from inconspicuous camouflage to ostentatious sexual display, and can provide important information about the environment and biology of a particular organism. The most ubiquitous and abundant pigment, melanin, also has a diverse range of non-visual roles, including thermoregulation in ectotherms. However, little is known about the functional evolution of this important biochrome through deep time, owing to our limited ability to unambiguously identify traces of it in the fossil record. Here we present direct chemical evidence of pigmentation in fossilized skin, from three distantly related marine reptiles: a leatherback turtle, a mosasaur and an ichthyosaur. We demonstrate that dark traces of soft tissue in these fossils are dominated by molecularly preserved eumelanin, in intimate association with fossilized melanosomes. In addition, we suggest that contrary to the countershading of many pelagic animals, at least some ichthyosaurs were uniformly dark-coloured in life. Our analyses expand current knowledge of pigmentation in fossil integument beyond that of feathers, allowing for the reconstruction of colour over much greater ranges of extinct taxa and anatomy. In turn, our results provide evidence of convergent melanism in three disparate lineages of secondarily aquatic tetrapods. Based on extant marine analogues, we propose that the benefits of thermoregulation and/or crypsis are likely to have contributed to this melanisation, with the former having implications for the ability of each group to exploit cold environments.
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| 8. |
- Piel, Sarah, et al.
(författare)
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Bioenergetic bypass using cell-permeable succinate, but not methylene blue, attenuates metformin-induced lactate production
- 2018
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Ingår i: Intensive Care Medicine Experimental. - : Springer Science and Business Media LLC. - 2197-425X. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Metformin is the most common pharmacological treatment for type 2 diabetes. It is considered safe but has been associated with the development of lactic acidosis under circumstances where plasma concentrations exceed therapeutic levels. Metformin-induced lactic acidosis has been linked to the drug's toxic effect on mitochondrial function. Current treatment strategies aim to remove the drug and correct for the acidosis. With a mortality of 20%, complementary treatment strategies are needed. In this study, it was investigated whether targeting mitochondria with pharmacological agents that bypass metformin-induced mitochondrial dysfunction can counteract the energetic deficit linked to toxic doses of metformin.METHODS: The redox agent methylene blue and the cell-permeable succinate prodrug NV118 were evaluated by measuring mitochondrial respiration and lactate production of human platelets exposed to metformin and co-treated with either of the two pharmacological bypass agents.RESULTS: The cell-permeable succinate prodrug NV118 increased mitochondrial respiration which was linked to phosphorylation by the ATP-synthase and alleviated the increase in lactate production induced by toxic doses of metformin. The redox agent methylene blue, in contrast, failed to mitigate the metformin-induced changes in mitochondrial respiration and lactate generation.CONCLUSIONS: The cell-permeable succinate prodrug NV118 bypassed the mitochondrial dysfunction and counteracted the energy deficit associated with toxic doses of metformin. If similar effects of NV118 prove translatable to an in vivo effect, this pharmacological strategy presents as a promising complementary treatment for patients with metformin-induced lactic acidosis.
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| 9. |
- Rossmeisl, Martin, et al.
(författare)
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Metabolic effects of n-3 PUFA as phospholipids are superior to triglycerides in mice fed a high-fat diet: Possible role of endocannabinoids
- 2012
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Background: n-3 polyunsaturated fatty acids, namely docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), reduce the risk of cardiovascular disease and can ameliorate many of obesity-associated disorders. We hypothesised that the latter effect will be more pronounced when DHA/EPA is supplemented as phospholipids rather than as triglycerides. Methodology/Principal Findings: In a 'prevention study', C57BL/6J mice were fed for 9 weeks on either a corn oil-based high-fat obesogenic diet (cHF; lipids ~35% wt/wt), or cHF-based diets in which corn oil was partially replaced by DHA/EPA, admixed either as phospholipids or triglycerides from marine fish. The reversal of obesity was studied in mice subjected to the preceding cHF-feeding for 4 months. DHA/EPA administered as phospholipids prevented glucose intolerance and tended to reduce obesity better than triglycerides. Lipemia and hepatosteatosis were suppressed more in response to dietary phospholipids, in correlation with better bioavailability of DHA and EPA, and a higher DHA accumulation in the liver, white adipose tissue (WAT), and muscle phospholipids. In dietary obese mice, both DHA/EPA concentrates prevented a further weight gain, reduced plasma lipid levels to a similar extent, and tended to improve glucose tolerance. Importantly, only the phospholipid form reduced plasma insulin and adipocyte hypertrophy, while being more effective in reducing hepatic steatosis and low-grade inflammation of WAT. These beneficial effects were correlated with changes of endocannabinoid metabolome in WAT, where phospholipids reduced 2-arachidonoylglycerol, and were more effective in increasing anti-inflammatory lipids such as N-docosahexaenoylethanolamine. Conclusions/Significance: Compared with triglycerides, dietary DHA/EPA administered as phospholipids are superior in preserving a healthy metabolic profile under obesogenic conditions, possibly reflecting better bioavalability and improved modulation of the endocannabinoid system activity in WAT. © 2012 Rossmeisl et al.
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| 10. |
- Sjövall, Peter, et al.
(författare)
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Dietary uptake of omega-3 fatty acids in mouse tissue studied by time-of-flight secondary ion mass spectrometry (TOF-SIMS)
- 2015
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Ingår i: Analytical and Bioanalytical Chemistry. - : Springer Science and Business Media LLC. - 1618-2642 .- 1618-2650. ; 407:17, s. 5101-5111
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Tidskriftsartikel (refereegranskat)abstract
- Dietary intake of omega-3 fatty acids is associated with considerable health benefits, including the prevention of metabolic disorders such as cardiovascular disease and type 2 diabetes. Furthermore, incorporation of the main omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), at the systemic level has been found to be more efficient when these fatty acids are supplied in the form of marine phospholipids compared to triglycerides. In this work, the uptake of omega-3 fatty acids and their incorporation in specific lipids were studied in adipose, skeletal muscle, and liver tissues of mice given high-fat diets with or without omega-3 supplements in the form of phospholipids or triglycerides using time-of-flight secondary ion mass spectrometry (TOF-SIMS). The results demonstrate significant uptake of EPA and DHA, and the incorporation of these fatty acids in specific lipid molecules, in all three tissue types in response to the dietary omega-3 supplements. Moreover, the results indicate reduced concentrations of arachidonic acid (AA) and depletion of lipids containing AA in tissue samples from mice given supplementary omega-3, as compared to the control mice. The effect on the lipid composition, in particular the DHA uptake and AA depletion, was found to be significantly stronger when the omega-3 supplement was supplied in the form of phospholipids, as compared to triglycerides. TOF-SIMS was found to be a useful technique for screening the lipid composition and simultaneously obtaining the spatial distributions of various lipid classes on tissue surfaces.
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