scholarly journals Therapeutic Effect of Local Injection of VX765 Sodium Alginate Nanogel on Myocardial Infarction

Author(s):  
Qingxin Tian ◽  
Jianlong Liu ◽  
Qin Chen ◽  
Mingxiao Zhang

Abstract Objectives: To determine the effect of polyethyleneimine/sodium alginate composite nano-gel (AG/PEI-VX765NGs) coated with VX765 on cardiac function in rats with myocardial infarction (MI). Methods: VX765-polyethyleneimine nano-microspheres (PEI-VX765 NP) were encapsulated by sodium alginate (AG) nanogel (NGs) to construct AG/PEI-VX765 NGs. The morphological observation was performed under scanning electron microscope (SEM). The viability was evaluated by using CCK-8 assay in vitro. Then, 24 male SPF Sprague-Dawley rats were randomly divided into 4 groups: Sham, MI, PEI-VX765NP, and AG/PEI-VX765NGs. After 28 days, rats in each group were subjected to assessment of cardiac function by echocardiography. The myocardial infarct size was evaluated by TTC test, and the differences in cardiac fibrosis and cardiomyocyte apoptosis between groups were analyzed by histological methods. Results: The prepared NGs shows a porous structure, while PEI-VX765 NP is uniformly distributed in the AG NGs samples. AG/PEI-VX765 NGs with a concentration of VX765 (range: 0-1000 μM) displayed no significant toxicity to cells. Meanwhile, we observed a relatively more persistent release of VX765 from AG/PEI-VX765 NGs compared with PEI-VX765. LVIDs and LVIDd in both PEI-VX765 and AG/PEI-VX765NGs groups were significantly smaller than those in MI group, while ejection fraction (EF) and short-axis shortening rate (FS) were markedly increased in the above-mentioned two groups. Compared with MI group, PEI-VX765 and AG/PEI-VX765NGs groups exhibited a significant reduction in the infarct size, degree of fibrosis, and the rate of TUNEL positive cells. Conclusion: AG/PEI-VX765NGs can significantly improve the cardiac function of rats with MI.

Author(s):  
Alexander B Veitinger ◽  
Audrey Komguem ◽  
Lena Assling-Simon ◽  
Martina Heep ◽  
Julia Schipke ◽  
...  

Abstract OBJECTIVES Esmolol-based cardioplegic arrest offers better cardioprotection than crystalloid cardioplegia but has been compared experimentally with blood cardioplegia only once. We investigated the influence of esmolol crystalloid cardioplegia (ECCP), esmolol blood cardioplegia (EBCP) and Calafiore blood cardioplegia (Cala) on cardiac function, metabolism and infarct size in non-infarcted and infarcted isolated rat hearts. METHODS Two studies were performed: (i) the hearts were subjected to a 90-min cardioplegic arrest with ECCP, EBCP or Cala and (ii) a regional myocardial infarction was created 30 min before a 90-min cardioplegic arrest. Left ventricular peak developed pressure (LVpdP), velocity of contractility (dLVP/dtmax), velocity of relaxation over time (dLVP/dtmin), heart rate and coronary flow were recorded. In addition, the metabolic parameters were analysed. The infarct size was determined by planimetry, and the myocardial damage was determined by electron microscopy. RESULTS In non-infarcted hearts, cardiac function was better preserved with ECCP than with EBCP or Cala relative to baseline values (LVpdP: 100 ± 28% vs 86 ± 11% vs 57 ± 7%; P = 0.002). Infarcted hearts showed similar haemodynamic recovery for ECCP, EBCP and Cala (LVpdP: 85 ± 46% vs 89 ± 55% vs 56 ± 26%; P = 0.30). The lactate production with EBCP was lower than with ECCP (0.6 ± 0.7 vs 1.4 ± 0.5 μmol/min; P = 0.017). The myocardial infarct size and (ECCP vs EBCP vs Cala: 16 ± 7% vs 15 ± 9% vs 24 ± 13%; P = 0.21) the ultrastructural preservation was similar in all groups. CONCLUSIONS In non-infarcted rat hearts, esmolol-based cardioplegia, particularly ECCP, offers better myocardial protection than Calafiore. After an acute myocardial infarction, cardioprotection with esmolol-based cardioplegia is similar to that with Calafiore.


2006 ◽  
Vol 290 (6) ◽  
pp. H2644-H2647 ◽  
Author(s):  
Micah S. Johnson ◽  
Russell L. Moore ◽  
David A. Brown

This study was conducted to examine the relationship between myocardial ATP-sensitive potassium (KATP) channels and sex differences in myocardial infarct size after in vitro ischemia-reperfusion (I/R). Hearts from adult male and female Sprague-Dawley rats were excised and exposed to an I/R protocol (1 h of ischemia, followed by 2 h of reperfusion) on a modified Langendorff apparatus. Hearts from female rats showed significantly smaller infarct sizes than hearts from males (23 ± 4 vs. 40 ± 5% of the zone at risk, respectively; P < 0.05). Administration of HMR-1098, a sarcolemmal KATP channel blocker, abolished the sex difference in infarct size (42 ± 4 vs. 45 ± 5% of the zone at risk in hearts from female and male rats, respectively; P = not significant). Further experiments showed that blocking the KATP channels in ischemia, and not reperfusion, was sufficient to increase infarct size in female rats. These data demonstrate that sarcolemmal KATP channels are centrally involved in mechanisms that underlie sex differences in the susceptibility of the intact heart to I/R injury.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Zhenjun Wu ◽  
Lihua Yu ◽  
Xinyue Li ◽  
Xuewen Li

Objective. To study the protective effect of trimetazidine on myocardial cells in rats with myocardial infarction and explore its effect on ERK signaling pathway. Methods. 40 SD rats were randomly divided into the sham operation group, model group, low-dose group, and high-dose group (intra-abdominal injection of trimetazidine 5 mg/kg and 10 mg/kg, respectively), construction of rat myocardial infarction model by coronary artery left anterior descending artery ligation. 7 days after surgery, the survival rate and cardiac function of each group of rats were recorded. The myocardial infarct size was detected by TTC staining. The apoptosis level of rat cardiomyocytes was detected by TUNEL staining. The content of ROS in rat cardiomyocytes was detected by DCFH-DA. Western-blot was used to detection of Caspase-3, Bcl-2/Bax, and ERK signaling pathway-related proteins in myocardial tissue. Results. Compared with the model group, the survival rate of the rats in the low-dose group and the high-dose group was significantly increased ( P < 0.01 ), the cardiac function was significantly improved ( P < 0.01 ), the myocardial infarct size was significantly decreased ( P < 0.01 ), the level of apoptosis was significantly decreased ( P < 0.01 ), the content of ROS in cardiomyocytes was significantly decreased ( P < 0.01 ), the protein expression of Caspase-3 and NF-κB in cardiomyocytes was significantly decreased ( P < 0.01 ), and the expression of Bcl-2/Bax and p-ERK were significantly increased ( P < 0.01 ). Conclusion. Trimetazidine can activate ERK signaling pathway in cardiomyocytes of rats with myocardial infarction, increase the expression of p-ERK, decrease the content of ROS in cardiomyocytes, decrease the expression of apoptotic proteins, reduce myocardial infarct size, improve cardiac function, and increase myocardial function.


2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Yun Wu ◽  
Yao Lu ◽  
Eric R Gross

Toxic reactive aldehydes are formed during ischemia-reperfusion. The ion channel transient receptor potential ankryin 1 (TRPA1) is irreversibly modified by reactive aldehydes which can cause calcium influx and cell death. Here we tested whether topically applied creams containing a reversible TRPA1 agonist could reduce myocardial infarct size. Male Sprague-Dawley rats 8-10 weeks age were subjected to an in vivo myocardial ischemia-reperfusion model of 30 minutes of left anterior descending (LAD) coronary artery ischemia followed by 2 hours reperfusion. Prior to ischemia, rats were untreated or had 1g of cream applied to the abdomen. The creams tested were IcyHot, Bengay, Tiger Balm, or preparation H (Fig. 1A). Hearts were negatively stained for the area at risk and the infarct size was determined by using TTC staining (Fig. 1B). A subset of rodents prior to receiving IcyHot also received an intravenous bolus of the TRPA1 antagonist TCS-5861528 (1mg/kg) or AP-18 (1mg/kg). Interestingly, both IcyHot and Bengay reduced myocardial infarct size compared to untreated rodents (Fig. 1C and 1D IcyHot: 41±3%*, Bengay: 50±2%* versus control 62±1%, n=6/group, *P<0.001). Both preparation H and Tiger Balm failed to reduce myocardial infarct size (Tiger Balm: 63±2%, preparation H 59±2%). Giving a TRPA1 antagonist prior to IcyHot also blocked the reduction in infarct size. Our additional data also indicates the methyl salicylate (mint) in IcyHot and Bengay is the agent that limits myocardial infarct size. Since IcyHot and Bengay are safely used by humans, targeting TRPA1 by using products such as these could be quickly translatable and widely used to reduce ischemia-reperfusion injury.


2013 ◽  
Vol 34 (suppl 1) ◽  
pp. P1309-P1309
Author(s):  
C. P. H. Lexis ◽  
W. G. Wieringa ◽  
B. Hiemstra ◽  
V. M. Van Deursen ◽  
E. Lipsic ◽  
...  

Author(s):  
Feng Tian ◽  
Ying Zhang

Our previous research has shown that type-2a Sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) undergoes posttranscriptional oxidative modifications in cardiac microvascular endothelial cells (CMECs) in the context of excessive cardiac oxidative injury. However, whether SERCA2a inactivity induces cytosolic Ca2+ imbalance in mitochondrial homeostasis is far from clear. Mitofusin2 (Mfn2) is well known as an important protein involved in endoplasmic reticulum (ER)/mitochondrial Ca2+ tethering and the regulation of mitochondrial quality. Therefore, the aim of our study was to elucidate the specific mechanism of SERCA2a-mediated Ca2+ overload in the mitochondria via Mfn2 tethering and the survival rate of the heart under conditions of cardiac microvascular ischemic injury. In vitro, CMECs extracted from mice were subjected to 6 h of hypoxic injury to mimic ischemic heart injury. C57-WT and Mfn2KO mice were subjected to a 1 h ischemia procedure via ligation of the left anterior descending branch to establish an in vivo cardiac ischemic injury model. TTC staining, immunohistochemistry and echocardiography were used to assess the myocardial infarct size, microvascular damage, and heart function. In vitro, ischemic injury induced irreversible oxidative modification of SERCA2a, including sulfonylation at cysteine 674 and nitration at tyrosine 294/295, and inactivation of SERCA2a, which initiated calcium overload. In addition, ischemic injury-triggered [Ca2+]c overload and subsequent [Ca2+]m overload led to mPTP opening and ΔΨm dissipation compared with the control. Furthermore, ablation of Mfn2 alleviated SERCA2a-induced mitochondrial calcium overload and subsequent mito-apoptosis in the context of CMEC hypoxic injury. In vivo, compared with that in wild-type mice, the myocardial infarct size in Mfn2KO mice was significantly decreased. In addition, the findings revealed that Mfn2KO mice had better heart contractile function, decreased myocardial infarction indicators, and improved mitochondrial morphology. Taken together, the results of our study suggested that SERCA2a-dependent [Ca2+]c overload led to mitochondrial dysfunction and activation of Mfn2-mediated [Ca2+]m overload. Overexpression of SERCA2a or ablation of Mfn2 expression mitigated mitochondrial morphological and functional damage by modifying the SERCA2a/Ca2+-Mfn2 pathway. Overall, these pathways are promising therapeutic targets for acute cardiac microvascular ischemic injury.


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