scholarly journals Autophagic Flux Impairment Exacerbates Myocardial Ischemia-Reperfusion Injury in Experimental Diabetes Through Atg5/LAMP2 Cleavage by Calpains

2020 ◽  
Author(s):  
Lichun Guan ◽  
Ziqin Yu ◽  
Zhimei Che ◽  
Hang Zhang ◽  
Yong Yu ◽  
...  

Abstract Background: is a chronic metabolic disease characterized by hyperglycemia, which has negative effects on cardiac revascularization in patients with coronary artery disease (CAD). Methods: This study focused on the role of autophagic flux in regulating susceptibility of STZ-induced diabetic heart to ischemia-reperfusion (I/R) injury. We established STZ-induced diabetes mice and perform I/R process by coronary artery ligation, and neonatal mice cardiomyocytes culture subjected to high glucose and hypoxia/reoxygenation(H/R). Results: Diabetic heart was more sensitive to I/R injury. Autophagic flux, represented by TEM, relative LC3Ⅱ changes under CQ intervention and P62 expression, was impaired in diabetic hearts and deteriorated during subsequent I/R. Calpains were activated in diabetic I/R heart, and the inhibition of calpains partially rescued autophagic flux, cardiac function, and cell death. The expression of autophagic flux related proteins Atg5 and LAMP2 decreased significantly in diabetic I/R heart. Further studies suggested that calpain could cleave Atg5 and LAMP2, and generate cleaved fragments, which might be reversed by calpain inhibition. Inhibition of calpain,or in company with overexpression of Atg5 and LAMP2 , could reduce myocardial injury in diabetic heart subject to I/R. But overexpression of Atg5 alone could worsen the I/R injury. Conclusion: In conclusion, calpain-mediated cleavage of Atg5 and LAMP2 accounts for the impaired autophagic flux which increases the susceptibility to myocardial I/R injury in experimental diabetic mice.

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Kun Liu ◽  
Manman Li ◽  
Xiumei Ren ◽  
Qing-sheng You ◽  
Fei Wang ◽  
...  

The aim of this study was to study the protective effect of Huang Qi Tong Bi Decoction (HQTBT) on the heart of rats. Ischemia-reperfusion injury was established by coronary artery ligation. Proinflammatory cytokines were decreased by XFZY in coronary artery ligated rats. ST segment was also restored with the treatment of HQTBT. Triphenyltetrazole chloride (TTC) staining and pathological analysis showed that HQTBT reduced myocardial injury. Besides, the expressions of HMGB1/TLR/NF-κB pathway in rats were significantly decreased by HQTBT. This study shows that HQTBT inhibited inflammatory reaction on myocardial injury in rats.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Chung-Chuan Chou ◽  
Hui-Ling Lee ◽  
Gwo-Jyh Chang ◽  
Hung-Ta Wo ◽  
Tzung-Hai Yen ◽  
...  

AbstractStudies have demonstrated that diabetic (db/db) mice have increased susceptibility to myocardial ischemia–reperfusion (IR) injury and ventricular tachyarrhythmias (VA). We aimed to investigate the antiarrhythmic and molecular mechanisms of ranolazine in db/db mouse hearts with acute IR injury. Ranolazine was administered for 1 week before coronary artery ligation. Diabetic db/db and control db/+ mice were divided into ranolazine-given and -nongiven groups. IR model was created by 15-min left coronary artery ligation and 10-min reperfusion. In vivo electrophysiological studies showed that the severity of VA inducibility was higher in db/db mice than control (db/ +) mice. Ranolazine suppressed the VA inducibility and severity. Optical mapping studies in Langendorff-perfused hearts showed that ranolazine significantly shortened action potential duration, Cai transient duration, Cai decay time, ameliorated conduction inhomogeneity, and suppressed arrhythmogenic alternans induction. Western blotting studies showed that the expression of pThr17-phospholamban, calsequestrin 2 and voltage-gated sodium channel in the IR zone was significantly downregulated in db/db mice, which was ameliorated with ranolazine pretreatment and might play a role in the anti-arrhythmic actions of ranolazine in db/db mouse hearts with IR injury.


2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Sana Irfan Khan ◽  
Rajiv Kumar Malhotra ◽  
Neha Rani ◽  
Anil Kumar Sahu ◽  
Ameesha Tomar ◽  
...  

Xanthine oxidase and xanthine dehydrogenase have been implicated in producing myocardial damage following reperfusion of an occluded coronary artery. We investigated and compared the effect of febuxostat and allopurinol in an experimental model of ischemia-reperfusion (IR) injury with a focus on the signaling pathways involved. Male Wistar rats were orally administered vehicle (CMC) once daily (sham and IR + control), febuxostat (10 mg/kg/day; FEB10 + IR), or allopurinol (100 mg/kg/day; ALL100 + IR) for 14 days. On the 15th day, the IR-control and treatment groups were subjected to one-stage left anterior descending (LAD) coronary artery ligation for 45 minutes followed by a 60-minute reperfusion. Febuxostat and allopurinol pretreatment significantly improved cardiac function and maintained morphological alterations. They also attenuated oxidative stress and apoptosis by suppressing the expression of proapoptotic proteins (Bax and caspase-3), reducing TUNEL-positive cells, and increasing the level of antiapoptotic proteins (Bcl-2). The MAPK-based molecular mechanism revealed suppression of active JNK and p38 proteins concomitant with the rise in ERK1/ERK2, a prosurvival kinase. Additionally, a reduction in the level of inflammatory markers (TNF-α, IL-6, and NF-κB) was also observed. The changes observed with febuxostat were remarkable in comparison with those observed with allopurinol. Febuxostat protects relatively better against IR injury than allopurinol by suppressing inflammation and apoptosis mediating the MAPK/NF-κBp65/TNF-α pathway.


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Luo Pei ◽  
Hou Shaozhen ◽  
Dong Gengting ◽  
Chen Tingbo ◽  
Liu Liang ◽  
...  

Mechanisms forPanax ginseng’s cardioprotective effect against ischemia reperfusion injury involve the estrogen-mediated pathway, but little is known about the role of androgen. A standardizedPanax ginsengextract (RSE) was orally given with or without flutamide in a left anterior descending coronary artery ligation rat model. Infarct size, CK and LDH activities were measured. Time-related changes of NO, PI3K/Akt/eNOS signaling, and testosterone concentration were also investigated. RSE (80 mg/kg) significantly inhibited myocardial infarction and CK and LDH activities, while coadministration of flutamide abolished this effect of RSE. NO was increased by RSE and reached a peak after 15 min of ischemia; however, flutamide cotreatment suppressed this elevation. Western blot analysis showed that RSE significantly reversed the decreases of expression and activation of PI3K, Akt, and eNOS evoked by ischemia, whereas flutamide attenuated the effects of these protective mechanisms induced by RSE. RSE completely reversed the dropping of endogenous testosterone level induced by I/R injury. Flutamide plus RSE treatment not only abolished RSE’s effect but also produced a dramatic change on endogenous testosterone level after pretreatment and ischemia. Our results for the first time indicate that blocking androgen receptor abolishes the ability ofPanax ginsengto protect the heart from myocardial I/R injury.


2020 ◽  
Author(s):  
Chung-Chuan Chou ◽  
Hui-Ling Lee ◽  
Gwo-Jyh Chang ◽  
Hung-Ta Wo ◽  
Tzung-Hai Yen ◽  
...  

Abstract Background: Studies have demonstrated that db/db mice have increased susceptibility to myocardial ischemia-reperfusion (IR) injury and ventricular tachyarrhythmias (VA). We aimed to investigate the antiarrhythmic and molecular mechanisms of ranolazine in db/db mouse hearts with acute IR injury.Methods: Ranolazine was administered for 1 week before coronary artery ligation. Diabetic db/db and control db/+ mice were divided into ranolazine-given and -nongiven groups. IR model was created by 15-min left coronary artery ligation and 10-min reperfusion. In vivo electrophysiological studies and optical mapping to simultaneously record intracellular Ca2+ (Cai) and membrane voltage in Langendorff-perfused hearts were performed. Western blotting and whole-cell patch clamp study were performed to evaluate the effect of ranolazine in the non-IR and IR zones. Results: The severity of VA inducibility by burst pacing was higher in db/db mice than db/+ mice with acute IR injury. Ranolazine suppressed VA inducibility and severity in db/db and db/+ mice. Optical mapping studies showed that ranolazine significantly shortened action potential duration (APD80), Cai transient duration (CaiTD80), Cai decay time, ameliorated conduction inhomogeneity, and suppressed arrhythmogenic alternans induction. The expression of pThr17-phospholamban, calsequestrin 2 and SCN5A in the IR zone was significantly downregulated in db/db mice, which was ameliorated by ranolazine. Conclusions: Ranolazine pretreatment shortens APD80 and CaiTD80, reduces Cai decay time, and ameliorates conduction velocity inhomogeneity to suppress induction of arrhythmogenic alternans and VA; and amelioration of downregulation of pThr17-phospholamban, calsequestrin 2 and SCN5A may partly underlie the anti-arrhythmic molecular mechanisms of ranolazine in db/db mouse hearts with IR injury.


Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Adolfo G Mauro ◽  
Juan Valle Raleigh ◽  
Khoa Nguyen ◽  
David E Durrant ◽  
Erica Kim ◽  
...  

Background: Hydrogen sulfide (H2S) has been shown to attenuate myocardial ischemia/reperfusion injury via suppression of NOD-like receptor family, pyrin domain containing 3 (NLRP3) inflammasome. Whether the H2S donor, Na2S, protects against ischemic heart failure with reduced ejection fraction (HFrEF) when treatment is initiated after development of LV dysfunction is unknown. Methods and Results: Adult male mice underwent myocardial infarction (MI) by permanent coronary artery ligation after baseline echocardiography. Repeat echocardiography was performed at day 3 post MI and surviving mice with fractional shortening (FS) less than 25% were treated with either Na2S (100 μg/kg, ip) or saline (volume matched, ip) for 25 days. LV fractional shortening remained unchanged at 7 and 28 days post-MI in the saline group, but improved significantly with Na2S at both time points (Fig. A). Moreover, LV infarct scar size, assessed by trichrome staining, was smaller in Na2S group (14.8 ± 2.1%) as compared to control (28.8 ± 4.8%, P<0.05) at 7 days post MI. Immunofluorescence staining for apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC), a component of the inflammasome, showed significant increase at 3 days post MI with sustained elevation at 7 days in the saline-treated group, whereas treatment with Na2S starting on day 3 post-MI significantly attenuated ASC 4 days later (Fig. B). Survival rate was 2-fold higher in Na2S group compared to saline control at 28 days post MI (P<0.05, Fig. C). Conclusion: Treatment with Na2S in mice with ischemic HFrEF improves LV function and survival up to 28 days post MI, possibly through suppression of ASC and prevention of further NLRP3 inflammasome formation. We propose that H2S donors can be promising therapeutic tools for ischemic HF.


2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Kun Liu ◽  
Fei Wang ◽  
Shuo Wang ◽  
Wei-Nan Li ◽  
Qing Ye

The aim of this study was to investigate the cardioprotective effect of mangiferin (MAF) in vitro and in vivo. Oxidative stress and inflammatory injury were detected in coronary artery ligation in rats and also in hypoxia-reoxygenation- (H/R-) induced H9c2 cells. MAF inhibited myocardial oxidative stress and proinflammatory cytokines in rats with coronary artery occlusion. The ST segment of MAF treatment groups also resumed. Triphenyltetrazolium chloride (TTC) staining and pathological analysis showed that MAF could significantly reduce myocardial injury. In vitro data showed that MAF could improve hypoxia/reoxygenation- (H/R-) induced H9c2 cell activity. In addition, MAF could significantly reduce oxidative stress and inflammatory pathway protein expression in H/R-induced H9c2 cells. This study has clarified the protective effects of MAF on myocardial injury and also confirmed that oxidative stress and inflammation were involved in the myocardial ischemia-reperfusion injury (I/R) model.


2012 ◽  
Vol 303 (5) ◽  
pp. H605-H618 ◽  
Author(s):  
Lanfang Li ◽  
Heng Zeng ◽  
Jian-Xiong Chen

Apelin is an endogenous ligand for the angiotensin-like 1 receptor (APJ) and has beneficial effects against myocardial ischemia-reperfusion injury. Little is known about the role of apelin in the homing of vascular progenitor cells (PCs) and cardiac functional recovery postmyocardial infarction (post-MI). The present study investigated whether apelin affects PC homing to the infarcted myocardium, thereby mediating repair and functional recovery post-MI. Mice were infarcted by coronary artery ligation, and apelin-13 (1 mg·kg−1·day−1) was injected for 3 days before MI and for 14 days post-MI. Homing of vascular PCs [CD133+/c-Kit+/Sca1+, CD133+/stromal cell-derived factor (SDF)-1α+, and CD133+/CXC chemokine receptor (CXCR)-4+] into the ischemic area was examined. Myocardial Akt, endothelial nitric oxide synthase (eNOS), VEGF, jagged1, notch3, SDF-1α, and CXCR-4 expression were assessed at 24 h and 14 days post-MI. Functional analyses were performed on day 14 post-MI. Mice that received apelin-13 treatment demonstrated upregulation of SDF-1α/CXCR-4 expression and dramatically increased the number of CD133+/c-Kit+/Sca1+, CD133+/SDF-1α+, and c-Kit+/CXCR-4+ cells in infarcted hearts. Apelin-13 also significantly increased Akt and eNOS phosphorylation and upregulated VEGF, jagged1, and notch3 expression in ischemic hearts. This was accompanied by a significant reduction of myocardial apoptosis. Furthermore, treatment with apelin-13 promoted myocardial angiogenesis and attenuated cardiac fibrosis and hypertrophy together with a significant improvement of cardiac function at 14 days post-MI. Apelin-13 increases angiogenesis and improves cardiac repair post-MI by a mechanism involving the upregulation of SDF-1α/CXCR-4 and homing of vascular PCs.


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