scholarly journals Adiponectin Facilitates Postconditioning Cardioprotection through Both AMPK-Dependent Nuclear and AMPK-Independent Mitochondrial STAT3 Activation

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Qiqi Zhu ◽  
Haobo Li ◽  
Xiang Xie ◽  
Xiaozhen Chen ◽  
Ramoji Kosuru ◽  
...  

Myocardial ischemic postconditioning- (IPo-) mediated cardioprotection against myocardial ischemia-reperfusion (IR) injury needs the activation of signal transducer and activator of transcription 3 (STAT3), which involves adiponectin (APN). APN confers its biological effects through AMP-activated protein kinase- (AMPK-) dependent and AMPK-independent pathways. However, the role of AMPK in APN-mediated STAT3 activation in IPo cardioprotection is unknown. We hypothesized that APN-mediated STAT3 activation in IPo is AMPK-independent and that APN through AMPK-dependent STAT3 activation facilitates IPo cardioprotection. Here, Sprague-Dawley rats were subjected to myocardial IR without or with IPo and/or APN. APN or IPo significantly improved postischemic cardiac function and reduced myocardial injury and oxidative stress, and their combination further attenuated postischemic myocardial injuries. APN or its combination with IPo but not IPo alone significantly increased AMPK activation and both nuclear and mitochondrial STAT3 activation, while IPo significantly enhanced mitochondrial but not nuclear STAT3 activation. In primarily isolated cardiomyocytes, recombined globular APN (gAd), hypoxic postconditioning (HPo), or their combination significantly attenuated hypoxia/reoxygenation-induced cell injury and increased nuclear and/or mitochondrial STAT3 activation. STAT3 inhibition had no impact on gAd or gAd in combination with HPo-induced AMPK activation but abolished their cellular protective effects. AMPK inhibition did not affect HPo cardioprotection but abolished gAd cardioprotection and disabled gAd to facilitate/enhance HPo cardioprotection and STAT3 activation. These results suggest that APN confers cardioprotection through AMPK-dependent and AMPK-independent STAT3 activation, while IPo confers cardioprotection through AMPK-independent mitochondrial STAT3 activation. Joint use of APN and IPo synergistically attenuated myocardial IR injury by activating STAT3 via distinct signaling pathways.

2016 ◽  
Vol 94 (3) ◽  
pp. 245-250 ◽  
Author(s):  
Hong Dan ◽  
Liping Zhang ◽  
Xiaolin Qin ◽  
Xiaohui Peng ◽  
Mingyan Wong ◽  
...  

Moutan cortex (MC) is a traditional Chinese medicine with diverse biological effects. The present study was performed to investigate the effects of MC on myocardial ischemia/reperfusion (I/R) in rats and to explore its possible mechanisms. Sprague-Dawley rats were administered MC extract (1.98 g/kg, i.g.) for 14 days and underwent a subsequent open-chest procedure involving 30 min of myocardial ischemia and 60 min of reperfusion. The cardioprotective effect of MC was demonstrated by reduced infarct size and marked improvement in the histopathological examination. The increase in the activity of superoxide dismutase (SOD) and glutathione (GSH) as well as the reduction of malondialdehyde (MDA) indicated that MC effectively promoted the anti-oxidative defense system. Increased anti-oxidative defense was accompanied by decreased release of lactate dehydrogenase (LDH) and creatine kinase (CK). The reduction in TUNEL-positive myocytes demonstrated that MC decreased myocardial apoptosis. The mRNA expression of B cell leukemia-2 (Bcl-2) was upregulated by MC and the ratio of Bcl-2/Bcl-2-associated X protein (Bax) mRNA expression was increased. MC pretreatment decreased the mRNA expression of inducible nitric oxide synthase (iNOS). The data from this study suggest that MC exerted protective effects on acute myocardial I/R injury via anti-oxidative and anti-apoptotic activities.


2001 ◽  
Vol 91 (4) ◽  
pp. 1828-1835 ◽  
Author(s):  
Nicole Stupka ◽  
Peter M. Tiidus

The effects of estrogen and ovariectomy on indexes of muscle damage after 2 h of complete hindlimb ischemia and 2 h of reperfusion were investigated in female Sprague-Dawley rats. The rats were assigned to one of three experimental groups: ovariectomized with a 17β-estradiol pellet implant (OE), ovariectomized with a placebo pellet implant (OP), or control with intact ovaries (R). It was hypothesized that following ischemia-reperfusion (I/R), muscle damage indexes [serum creatine kinase (CK) activity, calpain-like activity, inflammatory cell infiltration, and markers of lipid peroxidation (thiobarbituric-reactive substances)] would be lower in the OE and R rats compared with the OP rats due to the protective effects of estrogen. Serum CK activity following I/R was greater ( P < 0.01) in the R rats vs. OP rats and similar in the OP and OE rats. Calpain-like activity was greatest in the R rats ( P < 0.01) and similar in the OP and OE rats. Neutrophil infiltration was assessed using the myeloperoxidase (MPO) assay and immunohistochemical staining for CD43-positive (CD43+) cells. MPO activity was lower ( P < 0.05) in the OE rats compared with any other group and similar in the OP and R rats. The number of CD43+ cells was greater ( P < 0.01) in the OP rats compared with the OE and R rats and similar in the OE and R rats. The OE rats had lower ( P < 0.05) thiobarbituric-reactive substance content following I/R compared with the R and OP rats. Indexes of muscle damage were consistently attenuated in the OE rats but not in the R rats. A 10-fold difference in serum estrogen content may mediate this. Surprisingly, serum CK activity and muscle calpain-like activity were lower ( P< 0.05) in the OP rats compared with the R rats. Increases in serum insulin-like growth factor-1 content ( P < 0.05) due to ovariectomy were hypothesized to account for this finding. Thus both ovariectomy and estrogen supplementation have differential effects on indexes of I/R muscle damage.


Antioxidants ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 167 ◽  
Author(s):  
Sajeela Ahmed ◽  
Naseer Ahmed ◽  
Alessio Rungatscher ◽  
Daniele Linardi ◽  
Bibi Kulsoom ◽  
...  

Consumption of flavonoid-rich nutraceuticals has been associated with a reduction in coronary events. The present study analyzed the effects of cocoa flavonols on myocardial injury following acute coronary ischemia-reperfusion (I/R). A commercially available cocoa extract was identified by chromatographic mass spectrometry. Nineteen different phenolic compounds were identified and 250 mg of flavan-3-ols (procyanidin) were isolated in 1 g of extract. Oral administration of cocoa extract in incremental doses from 5 mg/kg up to 25 mg/kg daily for 15 days in Sprague Dawley rats (n = 30) produced a corresponding increase of blood serum polyphenols and become constant after 15 mg/kg. Consequently, the selected dose (15 mg/kg) of cocoa extract was administered orally daily for 15 days in a treated group (n = 10) and an untreated group served as control (n = 10). Both groups underwent surgical occlusion of the left anterior descending coronary artery and reperfusion. Cocoa extract treatment significantly reversed membrane peroxidation, nitro-oxidative stress, and decreased inflammatory markers (IL-6 and NF-kB) caused by myocardial I/R injury and enhanced activation of both p-Akt and p-Erk1/2. Daily administration of cocoa extract in rats is protective against myocardial I/R injury and attenuate nitro-oxidative stress, inflammation, and mitigates myocardial apoptosis.


2007 ◽  
Vol 292 (5) ◽  
pp. H2432-H2437 ◽  
Author(s):  
Adam J. Chicco ◽  
Micah S. Johnson ◽  
Casey J. Armstrong ◽  
Joshua M. Lynch ◽  
Ryan T. Gardner ◽  
...  

The present study was conducted to determine whether the infarct sparing effect of short-term exercise is dependent on the operation of the myocardial sarcolemmal ATP-sensitive K+ (KATP) channel. Adult male and female Sprague-Dawley rats were exercised on a motorized treadmill for 5 days. Twenty-four hours following the training or sedentary period, hearts were isolated and exposed to 1 h of regional ischemia followed by 2 h of reperfusion on a modified Langendorf apparatus in the presence or absence of the sarcolemmal KATP channel antagonist HMR-1098 (30 μM). Following the ischemia-reperfusion protocol, infarct size was determined as a percentage of the total ischemic zone at risk (ZAR). Short-term exercise reduced infarct size by 24% in males (32 ± 2% of ZAR; P < 0.01) and by 18% in females (26 ± 2% of ZAR; P < 0.05). Sarcolemmal KATP channel blockade abolished the training-induced cardioprotection in both males and females, increasing infarct size to 43 ± 3% and 52 ± 4% of ZAR, respectively. In the absence of HMR-1098, infarct size was significantly lower in sedentary females than in males (33 ± 4% vs. 42 ± 2% of ZAR, respectively; P < 0.01). However, the presence of HMR-1098 abolished this sex difference, increasing infarct size by 58% in the sedentary females ( P < 0.01) but having no effect on infarct size in sedentary males. This study demonstrates that the sex-specific and exercise-acquired resistance to myocardial ischemia-reperfusion injury is dependent on sarcolemmal KATP activity during ischemia.


2009 ◽  
Vol 297 (2) ◽  
pp. F362-F370 ◽  
Author(s):  
Dae Eun Choi ◽  
Jin Young Jeong ◽  
Beom Jin Lim ◽  
Sarah Chung ◽  
Yoon Kyung Chang ◽  
...  

Sildenafil was the first selective inhibitor of phosphodiesterase-5 (PDE5) to be widely used for treating erectile dysfunction. Many recent studies have investigated the cardioprotective role of sildenafil in animal models. We evaluated the protective effects of sildenafil in experimental renal ischemia-reperfusion (IR) injury in two studies. In study 1, male Sprague-Dawley rats were divided into four groups: sham, sildenafil-treated sham, vehicle-treated IR, and sildenafil-treated IR groups. In study 2, we divided the rats into two groups: sildenafil-treated IR rats and PD98059 (ERK inhibitor)+sildenafil-treated IR rats. Functional parameters of the kidney were evaluated at the molecular and structural levels. Blood urea nitrogen (BUN) and serum creatinine levels were lower in sildenafil-treated IR rats than in vehicle-treated IR rats. The expression of inducible (iNOS) and endothelial nitric oxide synthase (eNOS) proteins in sildenafil-treated IR rats was significantly higher than in vehicle-treated IR rats. Pretreatment with sildenafil in IR rats increased ERK phosphorylation and reduced the renal Bax/Bcl-2 ratio, renal caspase-3 activity, and terminal dUTP nick end-labeling-positive apoptotic cells. In contrast, PD98059 treatment increased BUN and serum creatinine levels and attenuated the sildenafil-induced expression of pERK, iNOS, eNOS, and Bcl-2. PD98059 also increased caspase-3 activity but did not decrease the sildenafil-induced accumulation of cGMP. In conclusion, this study suggests that sildenafil has antiapoptotic effects in experimental IR renal injury via ERK phosphorylation, induction of iNOS and eNOS production, and a decrease in the Bax/Bcl-2 ratio.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Weidong Qian ◽  
Xingjiang Xiong ◽  
Zhuyuan Fang ◽  
Haiting Lu ◽  
Zhensheng Wang

Myocardial ischemia-reperfusion injury (MIRI) is a common pathological and physiological phenomenon. Tetramethylpyrazine is the extract of the traditional Chinese medicine Chuanxiong, which can exert protective effects on MIRI in multiple ways. This paper reviewed the current research progress and evidence about the cardiovascular effects of tetramethylpyrazine, which included protecting mitochondria and improving energy metabolism, scavenging oxygen free radicals (OFRs) to inhibit lipid peroxidation, attenuating calcium (Ca2+) overload and maintaining Ca2+homeostasis in cells, inhibiting apoptosis and protecting myocardial cells, interfering with the inflammatory reaction and mitigating cell injury, interfering with cell signaling pathways, and improving function of endothelial cells and protecting myocardial cells. However, further rigorously designed randomized controlled trials are warranted.


2017 ◽  
Vol 313 (5) ◽  
pp. E577-E585 ◽  
Author(s):  
Tingting Li ◽  
Jie Xu ◽  
Xinghua Qin ◽  
Zuoxu Hou ◽  
Yongzheng Guo ◽  
...  

Myocardial reperfusion decreases glucose oxidation and uncouples glucose oxidation from glycolysis. Therapies that increase glucose oxidation lessen myocardial ischemia-reperfusion (I/R) injury. However, the regulation of glucose uptake during reperfusion remains poorly understood. We found that glucose uptake was remarkably diminished in the myocardium following reperfusion in Sprague-Dawley rats as detected by 18F–labeled and fluorescent-labeled glucose analogs, even though GLUT1 was upregulated by threefold and GLUT4 translocation remained unchanged compared with those of sham-treated rats. The decreased glucose uptake was accompanied by suppressed glucose oxidation. Interestingly, stimulating glucose oxidation by inhibition of pyruvate dehydrogenase kinase 4 (PDK4), a rate-limiting enzyme for glucose oxidation, increased glucose uptake and alleviated I/R injury. In vitro data in neonatal myocytes showed that PDK4 overexpression decreased glucose uptake, whereas its knockdown increased glucose uptake, suggesting that PDK4 has a role in regulating glucose uptake. Moreover, inhibition of PDK4 increased myocardial glucose uptake with concomitant enhancement of cardiac insulin sensitivity following myocardial I/R. These results showed that the suppressed glucose oxidation mediated by PDK4 contributes to the reduced glucose uptake in the myocardium following reperfusion, and enhancement of glucose uptake exerts cardioprotection. The findings suggest that stimulating glucose oxidation via PDK4 could be an efficient approach to improve recovery from myocardial I/R injury.


1994 ◽  
Vol 76 (2) ◽  
pp. 545-552 ◽  
Author(s):  
K. Hsu ◽  
D. Wang ◽  
S. Y. Wu ◽  
C. Y. Shen ◽  
H. I. Chen

The protective effect of ATP-MgCl2 on ischemia-reperfusion lung injury has been reported in kidney, liver, heart, and muscle but has not been examined in lungs. The aim of this study was to determine whether ATP or ATP-MgCl2 pretreatment would attenuate ischemia-reperfusion-induced acute lung injury and to identify the possible mechanisms for such protection. Typical acute lung injury was successfully induced in Sprague-Dawley rats by 10 min of hypoxia followed by 75 min of ischemia and 50 min of reperfusion. Pretreatment with ATP-MgCl2 (or adenosine) but not ATP or MgCl2 (all at 10(-6) M) significantly attenuated the acute lung injury. All the protective effects of ATP-MgCl2 were nearly undetectable when promazine (an ecto-adenosinetriphosphatase inhibitor) or 3,7-dimethyl-1-propargylxanthine (an A2-receptor antagonist) was added before ATP-MgCl2 pretreatment. These observations support our hypothesis that the protective effect of ATP-MgCl2 is in part mediated through adenosine, the degradation product of ATP, which is produced by the Mg(2+)-dependent ecto-adenosinetriphosphatase on the surface of neutrophils and reacts with neutrophil A2 receptors to inhibit the production of O2 radicals.


Author(s):  
CL Hastings ◽  
RD Carlton ◽  
FG Lightfoot ◽  
AF Tryka

The earliest ultrastructural manifestation of hypoxic cell injury is the presence of intracellular edema. Does this intracellular edema affect the ability to cryopreserve intact myocardium? To answer this guestion, a model for anoxia induced intracellular edema (IE) was designed based on clinical intraoperative myocardial preservation protocol. The aortas of 250 gm male Sprague-Dawley rats were cannulated and a retrograde flush of Plegisol at 8°C was infused over 90 sec. The hearts were excised and placed in a 28°C bath of Lactated Ringers for 1 h. The left ventricular free wall was then sliced and the myocardium was slam frozen. Control rats (C) were anesthetized, the hearts approached by median sternotomy, and the left ventricular free wall frozen in situ immediately after slicing. The slam frozen samples were obtained utilizing the DDK PS1000, which was precooled to -185°C in liguid nitrogen. The tissue was in contact with the metal mirror for a dwell time of 20 sec, and stored in liguid nitrogen until freeze dry processing (Lightfoot, 1990).


2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Zhimei Qiu ◽  
Yan Wang ◽  
Weiwei Liu ◽  
Chaofu Li ◽  
Ranzun Zhao ◽  
...  

AbstractAutophagy and apoptosis are involved in myocardial ischemia/reperfusion (I/R) injury. Research indicates that circular RNA HIPK3 (circHIPK3) is crucial to cell autophagy and apoptosis in various cancer types. However, the role of circHIPK3 in the regulation of cardiomyocyte autophagy and apoptosis during I/R remains unknown. Our study aimed to examine the regulatory effect of circHIPK3 during myocardial I/R and investigate its mechanism in cardiomyocyte autophagy and apoptosis. Methods and results. The expression of circHIPK3 was upregulated during myocardial I/R injury and hypoxia/reoxygenation (H/R) injury of cardiomyocytes. To study the potential role of circHIPK3 in myocardial H/R injury, we performed gain-of-function and loss-of-function analyses of circHIPK3 in cardiomyocytes. Overexpression of circHIPK3 significantly promoted H/R-induced cardiomyocyte autophagy and cell injury (increased intracellular reactive oxygen species (ROS) and apoptosis) compared to those in the control group, while silencing of circHIPK3 showed the opposite effect. Further research found that circHIPK3 acted as an endogenous miR-20b-5p sponge to sequester and inhibit miR-20b-5p activity, resulting in increased ATG7 expression. In addition, miR-20b-5p inhibitors reversed the decrease in ATG7 induced by silencing circHIPK3. Conclusions. CircHIPK3 can accelerate cardiomyocyte autophagy and apoptosis during myocardial I/R injury through the miR-20b-5p/ATG7 axis. These data suggest that circHIPK3 may serve as a potential therapeutic target for I/R.


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