Intravenous bilirubin provides incomplete protection against renal ischemia-reperfusion injury in vivo

Exogenous bilirubin (BR) substitutes for the protective effects of heme oxygenase (HO) in several organ systems. Our objective was to investigate the effects of exogenous BR in an in vivo model of ischemia-reperfusion injury (IRI) in the rat kidney. Four groups of male Sprague-Dawley rats were anesthetized using isoflurane in oxygen and treated with 1) 5 mg/kg intravenous (iv) BR, 1 h before ischemia and 6-h reperfusion; 2) vehicle 1 h before ischemia and 6-h reperfusion; 3) 20 mg/kg iv BR, 1 h before and during ischemia; and 4) vehicle 1 h before and during ischemia. Bilateral renal clamping (30 min) was followed by 6-h reperfusion. Infusion of 5 mg/kg iv BR achieved target levels in the serum at 6 h postischemia (31 ± 9 μmol/l). Infusion of 20 mg/kg BR reached 50 ± 22 μmol/l at the end of ischemia, and a significant improvement was seen in serum creatinine at 6 h (1.07 ± 28 vs. 1.38 ± 0.18 mg/dl, P = 0.043). Glomerular filtration rate, estimated renal plasma flow, fractional excretion of electrolytes, and renal vascular resistance were not significantly improved in BR-treated groups. Histological grading demonstrated a trend toward preservation of cortical proximal tubules in rats receiving 20 mg/kg iv BR compared with control; however, neither BR dose provided protection against injury to the renal medulla. At the doses administered, iv BR did not provide complete protection against IRI in vivo. Combined supplementation of both BR and carbon monoxide may be required to preserve renal blood flow and adequately substitute for the protective effects of HO in vivo.

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Effects of sodium nitrite on ischemia-reperfusion injury in the rat kidney

AJP Renal Physiology ◽

10.1152/ajprenal.00334.2005 ◽

2006 ◽

Vol 290 (4) ◽

pp. F779-F786 ◽

Cited By ~ 53

Author(s):

Mahesh Basireddy ◽

T. Scott Isbell ◽

Xinjun Teng ◽

Rakesh P. Patel ◽

Anupam Agarwal

Keyword(s):

Renal Injury ◽

Ischemia Reperfusion Injury ◽

Rat Kidney ◽

Ischemia Reperfusion ◽

Protective Effects ◽

Sprague Dawley ◽

Contralateral Kidney ◽

Treatment Groups ◽

Tubular Necrosis

Reactive oxygen and nitrogen species play a key role in the pathophysiology of renal ischemia-reperfusion (I/R) injury. Recent studies have shown that nitrite (NO2−) serves as an endogenous source of nitric oxide (NO), particularly in the presence of hypoxia and acidosis. Nanomolar concentrations of NO2− reduce injury following I/R in the liver and heart in vivo. The purpose of this study was to evaluate the role of NO2− in renal I/R injury. Male Sprague-Dawley rats underwent a unilateral nephrectomy followed by 45 min of ischemia of the contralateral kidney or sham surgery under isoflurane anesthesia. Animals received normal saline, sodium NO2−, or sodium nitrate (NO3−; 1.2 nmol/g body wt ip) at 22.5 min after induction of ischemia or 15 min before ischemia. A separate set of animals received saline, NO2−, or NO3− (0.12, 1.2, or 12 nmol/g body wt iv) 45 min before ischemia. Serum creatinine and blood urea nitrogen were increased following I/R injury but were not significantly different among treatment groups at 24 and 48 h after acute renal injury. Interestingly, NO3− administration appeared to worsen renal injury. Histological scoring for loss of brush border, tubular necrosis, and red blood cell extravasation showed no significant differences among the treatment groups. The results indicate that, contrary to the protective effects of NO2− in I/R injury of the liver and heart, NO2− does not provide protection in renal I/R injury and suggest a unique metabolism of NO2− in the kidney.

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Protective effects of exogenous bilirubin on ischemia-reperfusion injury in the isolated, perfused rat kidney

AJP Renal Physiology ◽

10.1152/ajprenal.00215.2004 ◽

2005 ◽

Vol 288 (4) ◽

pp. F778-F784 ◽

Cited By ~ 93

Author(s):

Christopher A. Adin ◽

Byron P. Croker ◽

Anupam Agarwal

Keyword(s):

Reperfusion Injury ◽

Ischemia Reperfusion Injury ◽

Rat Kidney ◽

Ischemia Reperfusion ◽

Heme Oxygenase 1 ◽

Protective Effects ◽

Reaction Products ◽

Isolated Perfused Rat Kidney ◽

Organ Systems ◽

Perfused Rat Kidney

Heme oxygenase-1 (HO-1) is induced as an adaptive and protective response to tissue injury. HO-1 degrades heme into carbon monoxide (CO) and biliverdin; the latter is then converted to bilirubin. These reaction products have powerful antiapoptotic and antioxidant effects. Manipulation of the HO-1 system by administration of micromolar doses of exogenous CO or bilirubin has been performed in several organ systems, but the dose-related effects of these reaction products have not been investigated in the kidney. The purpose of this study was to evaluate the efficacy and dose-related protective effects of 1 or 10 μM bilirubin flush before a 20-min period of warm ischemia. In an effort to minimize interactions with other chemical messengers or organ systems, we elected to use an isolated, perfused rat kidney model with an acellular, oxygenated perfusate. Using this model, we demonstrated that bilirubin treatment resulted in significant improvements in renal vascular resistance, urine output, glomerular filtration rate, tubular function, and mitochondrial integrity after ischemia-reperfusion injury (IRI). Beneficial effects on organ viability were achieved most consistently with a dose of 10 μM bilirubin. We conclude that the protective effects of HO-1 activity during IRI in the kidney are mediated, at least in part, by bilirubin and that pretreatment with micromolar doses of bilirubin may offer a simple and inexpensive method to improve renal function after IRI.

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Transient Receptor Potential Ankyrin 1 Activation within the Cardiac Myocyte Limits Ischemia–reperfusion Injury in Rodents

Anesthesiology ◽

10.1097/aln.0000000000001377 ◽

2016 ◽

Vol 125 (6) ◽

pp. 1171-1180 ◽

Cited By ~ 17

Author(s):

Yao Lu ◽

Honit Piplani ◽

Stacy L. McAllister ◽

Carl M. Hurt ◽

Eric R. Gross

Keyword(s):

Infarct Size ◽

Reperfusion Injury ◽

Cardiac Myocytes ◽

Cardiac Myocyte ◽

Transient Receptor Potential ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Cardiac Injury ◽

In Vivo Model

Abstract Background Recent evidence suggests that cross talk exists between cellular pathways important for pain signaling and ischemia–reperfusion injury. Here, the authors address whether the transient receptor potential ankyrin 1 (TRPA1) channel, important in pain signaling, is present in cardiac myocytes and regulates cardiac ischemia–reperfusion injury. Methods For biochemical analysis of TRPA1, techniques including quantitative polymerase chain reaction, Western blot, and immunofluorescence were used. To determine how TRPA1 mediates cellular injury, the authors used an in vivo model of rat cardiac ischemia–reperfusion injury and adult rat–isolated cardiac myocytes subjected to hypoxia–reoxygenation. Results The authors’ biochemical analysis indicates that TRPA1 is within the cardiac myocytes. Further, using a rat in vivo model of cardiac injury, the TRPA1 activators ASP 7663 and optovin reduce myocardial injury (45 ± 5%* and 44 ± 8%,* respectively, vs. control, 66 ± 6% infarct size/area at risk; n = 6 per group; mean ± SD; *P < 0.001). TRPA1 inhibition also blocked the infarct size–sparing effects of morphine. In isolated cardiac myocytes, the TRPA1 activators ASP 7663 and optovin reduce cardiac myocyte cell death when given during reoxygenation (20 ± 3%* and 22 ± 4%* vs. 36 ± 3%; percentage of dead cells per field, n = 6 per group; mean ± SD; *P < 0.05). For a rat in vivo model of cardiac injury, the infarct size–sparing effect of TRPA1 activators also occurs during reperfusion. Conclusions The authors’ data suggest that TRPA1 is present within the cardiac myocytes and is important in regulating myocardial reperfusion injury. The presence of TRPA1 within the cardiac myocytes may potentially explain why certain pain relievers that can block TRPA1 activation, such as cyclooxygenase-2 inhibitors or some nonsteroidal antiinflammatory drugs, could be associated with cardiovascular risk.

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The cardioprotection of dihydrotanshinone I against myocardial ischemia–reperfusion injury via inhibition of arachidonic acid ω-hydroxylase

Canadian Journal of Physiology and Pharmacology ◽

10.1139/cjpp-2016-0036 ◽

2016 ◽

Vol 94 (12) ◽

pp. 1267-1275 ◽

Cited By ~ 14

Author(s):

Yidan Wei ◽

Meijuan Xu ◽

Yi Ren ◽

Guo Lu ◽

Yangmei Xu ◽

...

Keyword(s):

Arachidonic Acid ◽

Myocardial Ischemia ◽

Reperfusion Injury ◽

Ischemia Reperfusion Injury ◽

Ischemia Reperfusion ◽

Protective Effects ◽

Myocardial Ischemia Reperfusion Injury ◽

Myocardial Ischemia Reperfusion

Arachidonic acid (AA) is a precursor that is metabolized by several enzymes to many biological eicosanoids. Accumulating data indicate that the ω-hydroxylation metabolite of AA, 20-hydroxyeicosatetraenoic acid (20-HETE), is considered to be involved in the myocardial ischemia–reperfusion injury (MIRI). The inhibitors of AA ω-hydroxylase, however, are demonstrated to exhibit protective effects on MIRI. Dihydrotanshinone I (DI), a bioactive constituent of danshen, is proven to be a potent inhibitor of AA ω-hydroxylase by our preliminary study in vitro. The purpose of the present study was to investigate the cardioprotection of DI against MIRI and its effects on the concentrations of 20-HETE in vivo. Rats subjected to 30 min of ischemia followed by 24 h of reperfusion were assigned to intravenously receive vehicle (sham and ischemia–reperfusion), low (1 mg/kg), middle (2 mg/kg), or high (4 mg/kg) doses of DI before reperfusion. The results demonstrated that DI treatment could improve cardiac function, reduce infarct size, ameliorate the variations in myocardial zymogram and histopathological disorders, decrease 20-HETE generation, and regulate apoptosis-related protein in myocardial ischemia–reperfusion rats. These findings suggested DI could exert considerable cardioprotective action on MIRI by the attenuation of 20-HETE generation, subsequent myocardial injury, and apoptosis through inhibition on AA ω-hydroxylase.

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Calenduloside E Ameliorates Myocardial Ischemia-Reperfusion Injury through Regulation of AMPK and Mitochondrial OPA1

Oxidative Medicine and Cellular Longevity ◽

10.1155/2020/2415269 ◽

2020 ◽

Vol 2020 ◽

pp. 1-12

Author(s):

Min Wang ◽

Rui-ying Wang ◽

Jia-hui Zhou ◽

Xue-heng Xie ◽

Gui-bo Sun ◽

...

Keyword(s):

Myocardial Ischemia ◽

Reperfusion Injury ◽

Ischemia Reperfusion Injury ◽

Mitochondrial Dynamics ◽

Ischemia Reperfusion ◽

Protective Effects ◽

Myocardial Ischemia Reperfusion Injury ◽

Myocardial Ischemia Reperfusion

Calenduloside E (CE) is a natural triterpenoid saponin isolated from Aralia elata (Miq.) Seem., a well-known traditional Chinese medicine. Our previous studies have shown that CE exerts cardiovascular protective effects both in vivo and in vitro. However, its role in myocardial ischemia/reperfusion injury (MIRI) and the mechanism involved are currently unknown. Mitochondrial dynamics play a key role in MIRI. This study investigated the effects of CE on mitochondrial dynamics and the signaling pathways involved in myocardial ischemia/reperfusion (MI/R). The MI/R rat model and the hypoxia/reoxygenation (H/R) cardiomyocyte model were established in this study. CE exerted significant cardioprotective effects in vivo and in vitro by improving cardiac function, decreasing myocardial infarct size, increasing cardiomyocyte viability, and inhibiting cardiomyocyte apoptosis associated with MI/R. Mechanistically, CE restored mitochondrial homeostasis against MI/R injury through improved mitochondrial ultrastructure, enhanced ATP content and mitochondrial membrane potential, and reduced mitochondrial permeability transition pore (MPTP) opening, while promoting mitochondrial fusion and preventing mitochondrial fission. However, genetic silencing of OPA1 by siRNA abolished the beneficial effects of CE on cardiomyocyte survival and mitochondrial dynamics. Moreover, we demonstrated that CE activated AMP-activated protein kinase (AMPK) and treatment with the AMPK inhibitor, compound C, abolished the protective effects of CE on OPA1 expression and mitochondrial function. Overall, this study demonstrates that CE is effective in mitigating MIRI by modulating AMPK activation-mediated OPA1-related mitochondrial fusion.

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