scholarly journals Human concentrations of uric acid scavenges adaptive and maladaptive reactive oxygen species in isolated rat hearts subjected to ischemic stress

2020 ◽  
Vol 98 (3) ◽  
pp. 139-146 ◽  
Author(s):  
Neoma T. Boardman ◽  
Aleksander Tank Falck ◽  
Trine Lund ◽  
Xi Chu ◽  
Montserrat Martin-Armas ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Uric Acid ◽  
Infarct Size ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Cardiac Response ◽  
Oxygen Species

Uric acid is a purine degradation product but also an important antioxidant and reactive oxygen species (ROS) scavenger. Experimental settings that mimic myocardial ischemia–reperfusion have not included uric acid despite that it is always present in human extracellular fluid and plasma. We hypothesized that uric acid has an important role in myocardial ROS scavenging. Here, we tested the cardiac response to uric acid on infarct size following ischemia–reperfusion with and without exacerbated oxidative stress due to acute pressure overload and during preconditioning. We also examined mitochondrial respiration and ROS-induced mitochondrial permeability transition pore opening. Under exacerbated ROS stress induced by high-pressure perfusion, uric acid lowered oxidative stress and reduced infarct size. In contrast, uric acid blocked cardioprotection induced by ischemic preconditioning. However, this effect was reversed by probenecid, an inhibitor of cellular uptake of uric acid. In accordance, in intact cardiomyocytes, extracellular uric acid reduced the susceptibility of mitochondria towards opening of the permeability transition pore, suggesting that uric acid may prevent ischemia–reperfusion injury due to scavenging of maladaptive ROS. Moreover, as uric acid also scavenges adaptive ROS, this may interfere with preconditioning. Altogether, uric acid might be a confounder when translating preclinical experimental results into clinical treatment.

Apoptosis in Heart and Skeletal Muscle

2002 ◽  
Vol 27 (4) ◽  
pp. 349-395 ◽  
Author(s):  
Andy J. Primeau ◽  
Peter J. Adhihetty ◽  
David A. Hood
Keyword(s):  
Reactive Oxygen Species ◽  
Skeletal Muscle ◽  
Cell Death ◽  
Mitochondrial Permeability Transition ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Permeability Transition ◽  
Current Evidence ◽  
Oxygen Species ◽  
Cellular Mechanisms

Apoptosis, or programmed cell death, is now recognized to be an important cellular event during normal development and in the progression of specific diseases. Apoptosis can be triggered by stimuli initiating outside of the cell, or within the mitochondria, leading to the activation of caspases and subsequent cell death. Although apoptosis has been widely studied in a variety of tissues over the last 5 years, skeletal muscle and heart have been relatively ignored in this regard. Research on apoptosis in cardiac muscle has recently taken on a higher profile as the recognition emerges that it may be an important contributor to specific cardiac pathologies, particularly in response to ischemia-reperfusion in which reactive oxygen species are formed. In skeletal muscle, very few studies have been done under specific physiological (e.g., exercise) and pathophysiological (e.g., dystrophies, denervation, myopathies) conditions. Skeletal muscle is unique in that it is mutli-nucleated, and evidence suggests that it can undergo individual myonuclear apoptosis as well as complete cell death. This review discusses the basic cellular mechanisms of apoptosis, as well as the current evidence of this process in cardiac and skeletal muscle. The need for more work in this area is highlighted, particularly in exercise and training. Key words: transcription factors, reactive oxygen species, mitochondria, caspase, mitochondrial permeability transition

Magnesium deficiency augments myocardial response to reactive oxygen species

2006 ◽  
Vol 84 (6) ◽  
pp. 617-624 ◽  
Author(s):  
L. Manju ◽  
R. Renuka Nair
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Lipid Peroxidation ◽  
Tissue Injury ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Inotropic Response ◽  
Mg Deficiency ◽  
Negative Inotropic Response

Magnesium (Mg) deficiency and oxidative stress are independently implicated in the etiopathogenesis of various cardiovascular disorders. This study was undertaken to examine the hypothesis that Mg deficiency augments the myocardial response to oxidative stress. Electrically stimulated rat papillary muscle was used for recording the contractile variation. Biochemical variables of energy metabolism (adenosine triphosphate (ATP) and creatine phosphate) and markers of tissue injury (lactate dehydrogenase (LDH) release and lipidperoxidation), which can affect myocardial contractility, were assayed in Langendorff-perfused rat hearts. Hydrogen peroxide (100 µmol/L) was used as the source of reactive oxygen species. The negative inotropic response to H2O2 was significantly higher in Mg deficiency (0.48 mmol Mg/L) than in Mg sufficiency (1.2 mmol Mg/L). Low Mg levels did not affect ATP levels or tissue lipid peroxidation. However, H2O2 induced a decrease in ATP; enhanced lipid peroxidation and the release of LDH were augmented by Mg deficiency. Increased lipid peroxidation associated with a decrease in available energy might be responsible for the augmentation of the negative inotropic response to H2O2 in Mg deficiency. The observations from this study validate the hypothesis that myocardial response to oxidative stress is augmented by Mg deficiency. This observation has significance in ischemia–reperfusion injury, where Mg deficiency can have an additive effect on the debilitating consequences.

scholarly journals A Monitoring of Allantoin, Uric Acid, and Malondialdehyde Levels in Plasma and Erythrocytes After Ten Minutes of Running Activity

2014 ◽  
pp. 753-762
Author(s):  
R. KANĎÁR ◽  
X. ŠTRAMOVÁ ◽  
P. DRÁBKOVÁ ◽  
J. KŘENKOVÁ
Keyword(s):  
Oxidative Stress ◽  
Reactive Oxygen Species ◽  
Uric Acid ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Intense Exercise ◽  
Suitable Candidate ◽  
Running Activity ◽  
Plasma Malondialdehyde

Uric acid is the final product of human purine metabolism. It was pointed out that this compound acts as an antioxidant and is able to react with reactive oxygen species forming allantoin. Therefore, the measurement of allantoin levels may be used for the determination of oxidative stress in humans. The aim of the study was to clarify the antioxidant effect of uric acid during intense exercise. Whole blood samples were obtained from a group of healthy subjects. Allantoin, uric acid, and malondialdehyde levels in plasma and erythrocytes were measured using a HPLC with UV/Vis detection. Statistical significant differences in allantoin and uric acid levels during short-term intense exercise were found. Immediately after intense exercise, the plasma allantoin levels increased on the average of 200 % in comparison to baseline. Plasma uric acid levels increased slowly, at an average of 20 %. On the other hand, there were no significant changes in plasma malondialdehyde. The results suggest that uric acid, important antioxidant, is probably oxidized by reactive oxygen species to allantoin. Therefore allantoin may be suitable candidate for a marker of acute oxidative stress.

scholarly journals Role of Mitochondrial Calcium and the Permeability Transition Pore in Regulating Cell Death

2020 ◽  
Vol 126 (2) ◽  
pp. 280-293 ◽  
Author(s):  
Tyler M. Bauer ◽  
Elizabeth Murphy
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Reactive Oxygen ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Mitochondrial Calcium ◽  
Oxygen Species ◽  
Inner Mitochondrial Membrane ◽  
Atp Production ◽  
Cell Death Pathways

Adult cardiomyocytes are postmitotic cells that undergo very limited cell division. Thus, cardiomyocyte death as occurs during myocardial infarction has very detrimental consequences for the heart. Mitochondria have emerged as an important regulator of cardiovascular health and disease. Mitochondria are well established as bioenergetic hubs for generating ATP but have also been shown to regulate cell death pathways. Indeed many of the same signals used to regulate metabolism and ATP production, such as calcium and reactive oxygen species, are also key regulators of mitochondrial cell death pathways. It is widely hypothesized that an increase in calcium and reactive oxygen species activate a large conductance channel in the inner mitochondrial membrane known as the PTP (permeability transition pore) and that opening of this pore leads to necroptosis, a regulated form of necrotic cell death. Strategies to reduce PTP opening either by inhibition of PTP or inhibiting the rise in mitochondrial calcium or reactive oxygen species that activate PTP have been proposed. A major limitation of inhibiting the PTP is the lack of knowledge about the identity of the protein(s) that form the PTP and how they are activated by calcium and reactive oxygen species. This review will critically evaluate the candidates for the pore-forming unit of the PTP and discuss recent data suggesting that assumption that the PTP is formed by a single molecular identity may need to be reconsidered.

scholarly journals Modulatory Effect of Myokines on Reactive Oxygen Species in Ischemia/Reperfusion

2020 ◽  
Vol 21 (24) ◽  
pp. 9382
Author(s):  
Márton Richárd Szabó ◽  
Márton Pipicz ◽  
Tamás Csont ◽  
Csaba Csonka
Keyword(s):  
Oxidative Stress ◽  
Physical Activity ◽  
Reactive Oxygen Species ◽  
Skeletal Muscle ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Interleukin 7 ◽  
Species Formation

There is a growing body of evidence showing the importance of physical activity against acute ischemic events in various organs. Ischemia/reperfusion injury (I/R) is characterized by tissue damage as a result of restriction and subsequent restoration of blood supply to an organ. Oxidative stress due to increased reactive oxygen species formation and/or insufficient antioxidant defense is considered to play an important role in I/R. Physical activity not only decreases the general risk factors for ischemia but also confers direct anti-ischemic protection via myokine production. Myokines are skeletal muscle-derived cytokines, representing multifunctional communication channels between the contracting skeletal muscle and other organs through an endocrine manner. In this review, we discuss the most prominent members of the myokines (i.e., brain-derived neurotrophic factor (BDNF), cathepsin B, decorin, fibroblast growth factors-2 and -21, follistatin, follistatin-like, insulin-like growth factor-1; interleukin-6, interleukin-7, interleukin-15, irisin, leukemia inhibitory factor, meteorin-like, myonectin, musclin, myostatin, and osteoglycin) with a particular interest in their potential influence on reactive oxygen and nitrogen species formation or antioxidant capacity. A better understanding of the mechanism of action of myokines and particularly their participation in the regulation of oxidative stress may widen their possible therapeutic use and, thereby, may support the fight against I/R.

scholarly journals The pH Hypothesis of Postconditioning

Circulation ◽  
2007 ◽  
Vol 115 (14) ◽  
pp. 1895-1903 ◽  
Author(s):  
Michael V. Cohen ◽  
Xi-Ming Yang ◽  
James M. Downey
Keyword(s):  
Reactive Oxygen Species ◽  
Mitochondrial Permeability Transition ◽  
Reactive Oxygen ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Oxygen Species ◽  
Risk Zone ◽  
Kinase C ◽  
Protective Signaling ◽  
Reactive Oxygen Species Scavenger

Background— It is unclear how reperfusion of infarcting hearts with alternating cycles of coronary reperfusion/occlusion attenuates infarction, but prevention of mitochondrial permeability transition pore (MPTP) formation is crucial. Acidosis also suppresses MPTP formation. We tested whether postconditioning protects by maintaining acidosis during early reoxygenation. Methods and Results— After 30-minute regional ischemia in isolated rabbit hearts, reperfusion with buffer (pH 7.4) caused 34.4±2.2% of the risk zone to infarct, whereas 2 minutes of postconditioning (6 cycles of 10-second reperfusion/10-second occlusion) at reperfusion resulted in 10.7±2.9% infarction. One minute (3 cycles) of postconditioning was not protective. Hypercapnic buffer (pH 6.9) for the first 2 minutes of reperfusion in lieu of postconditioning caused equivalent cardioprotection (15.0±2.6% infarction), whereas 1 minute of acidosis did not protect. Delaying postconditioning (6 cycles) or 2 minutes of acidosis for 1 minute aborted protection. Reperfusion with buffer (pH 7.7) blocked postconditioning protection, but addition of the MPTP closer cyclosporin A restored protection. Reactive oxygen species scavenger N-2-mercaptopropionyl glycine, protein kinase C antagonist chelerythrine, and mitochondrial K ATP channel closer 5-hydroxydecanoate each blocked protection from 2 minutes of acidosis as they did for postconditioning. Conclusion— Thus, postconditioning prevents MPTP formation by maintaining acidosis during the first minutes of reperfusion as reoxygenated myocardium produces reactive oxygen species that activate protective signaling to inhibit MPTP formation after pH normalization.

Sign in / Sign up

Export Citation Format

Share Document