Acute myocardial infarction is one of the major causes of mortality worldwide. Reperfusion in a timely fashion is the most effective way to limit infarct size. However, reperfusion can itself prompt further myocardial injury. This phenomenon is commonly known as myocardial ischemia-reperfusion (IR) injury. Mitochondrial aldehyde dehydrogenase (ALDH2) is an enzyme metabolizing acetaldehyde and toxic aldehydes. Increasing evidence has revealed a cardioprotective role of ALDH2 in myocardial IR injury. Evidence from animal studies has shown that ALDH2 diminishes acute myocardial infarct size, ameliorates cardiac dysfunction and prevents reperfusion arrhythmias. The activity of ALDH2 is severely compromised if it is encoded by the mutant ALDH2*2 gene, with an incidence of approximately 40% in Asian populations. Epidemiological surveys in the Asian population have depicted that ALDH2 polymorphism is closely associated with higher prevalence of acute myocardial infarction and coronary artery disease. Therefore, targeting ALDH2 may represent a promising avenue to protect against IR injury. This review recapitulates the underlying mechanisms involved in the protective effect of ALDH2 in cardiac IR injury. Translational potential of ALDH2 in the management of coronary heart disease is also discussed.
Aldehyde Dehydrogenase ; metabolism ; Animals ; Heart ; physiopathology ; Humans ; Mitochondria, Heart ; enzymology ; Myocardial Reperfusion Injury ; Myocardium ; pathology

OBJECTIVETo investigate the dynamic changes of expression of matrix metalloproteinases-9 in myocardium of mice with viral myocarditis (VMC) and its significance in the pathogenesis of viral myocarditis.

METHODSVMC model was prepared by an injection of CVB3 in BALB/C mice. The mice receiving an injection of culture solution without virus were used as the control group. Cardiac tissues were obtained 7, 14, 21 and 28 days after injection and made into paraffin sections. Myocardial histopathologic changes were observed by hematoxylin-eosin staining and Masson staining. The expression of MMP-9, type I collagen and type III collagen in cardiac tissues were quantified by SABC immunohistochemical method.

RESULTSThe expression of MMP-9 in the VMC model group was observed on the 7th day, reached a peak on the 14th day, and was significantly higher than that in the control group at all time points (P<0.05). Compared with the control group, the expression of type I collagen in the VMC model group was up-regulated on the 21st day and reached a peak on the 28th day (P<0.05). The expression of type III collagen in the VMC model group was significantly higher than that in the control group on the 28th day (P<0.05). The expression of MMP-9 was positively correlated with myocardial histopathologic scores (r=0.832, P<0.05) and negatively correlated with type I collagen expression (r=-0.791, P<0.05).

CONCLUSIONSMMP-9 is over-expressed at the early stage in VMC mice, and participates in the pathological process of VMC through mediating the degradation metabolism of type I collagen. It may be an important factor that leads to myocardial collagen remodeling and myocardial fibrosis.

Animals ; Collagen Type I ; analysis ; Collagen Type III ; analysis ; Coxsackievirus Infections ; enzymology ; Enterovirus B, Human ; Immunohistochemistry ; Male ; Matrix Metalloproteinase 9 ; analysis ; Mice ; Mice, Inbred BALB C ; Myocarditis ; enzymology ; pathology ; Myocardium ; enzymology ; pathology

OBJECTIVETo investigate the role of heme oxygenase-1 (HO-1) and its catalyst carbon monoxide (CO) in the development of myocardial damage and the effects of zinc protoporphyrin IX (ZnPPIX), an inhibitor of HO-1 on myocardium of mice with acute viral myocarditis.

METHODSA total of 112 inbred male Balb/C mice 4 - 6 weeks of age were divided randomly into 3 groups: the control group (C group, n = 32), the viral myocarditis group (V group, n = 40) and ZnPPIX group (Z group, n = 40). The Z and V groups were inoculated intraperitoneally (i.p.) with 0.1 ml of 10(-4.36) tissue culture infectious dose 50% (TCID(50))/ml Coxsackie virus B3 (CVB(3)) to produce viral myocarditis model on day 0, C group was injected i.p. with virus-free 1640 culture culture medium 0.1 ml at the same time, then operation was done as follows: the mice of group C and group V were injected i.p. with 0.1 ml NS each day. The mice of group Z were injected i.p. with 40 micromol per kilogram of body weight ZnPPIX (HO-1 inhibitor) qod. Eight mice of each group were sacrificed on days 4, 8, 15 and 21, respectively. The blood specimens were collected by taking out the eyeballs to test for the content of carboxyhemoglobin (COHb) using spectrophotometry and cardiac troponin I (cTnI) using chemiluminescent immunoassay. The hearts tissue slides were also stained by immunohistochemistry (IHC) for HO-1 and in situ hybridization (ISH) for HO-1 mRNA. The histological and ultrastructural changes were observed under light and electron microscopes.

RESULTS(1) The histopathological changes of myocardial cells: in the V and Z groups myocardial inflammatory cells infiltration reached the peak on day 8, the Z group histopathological scores were significantly lower than those in V group on day 8 (2.40 +/- 0.31 vs. 1.73 +/- 0.24, P < 0.01) and on day 15 (1.78 +/- 0.29 vs. 1.43 +/- 0.23, P < 0.05). No inflammation was present in group C. (2) The changes of serum cTnI level in both V and Z groups were significantly higher than those in C group on day 4, 8 and 15 (P < 0.01). The level in Z group was significantly lower than that in V group on day 4 [(6.074 +/- 1.475) ng/ml vs (7.911 +/- 1.225) ng/ml, P < 0.05] and day 8 [(0.821 +/- 0.294) ng/ml vs (1.480 +/- 0.454) ng/ml, P < 0.05]. (3) The changes of blood COHb level: compared with V group, in Z group the COHb level was lower on day 4 (P < 0.05) and day 15 (P < 0.01) after CVB(3) inoculation. Surprisingly, in Z group COHb level elevated suddenly on day 8 and showed conspicuously higher than that of V group (P < 0.01). (4) The result of HO-1 IHC staining: in both V and Z group myocardial cells had positive expression, while C group did not. (5) The results of HO-1 ISH were similar to those of HO-1 IHC, the A values of group Z was significantly lower than that of group V on day 4, 15 and 21(P < 0.01), but on day 8 it was higher than that of group C (P < 0.05).

CONCLUSIONHO-1 inhibitor, ZnPP not only could inhibit HO-1 overexpression but also could induce HO-1 expression temporarily and protect against myocardial injury at the early stage of acute viral myocarditis.

Animals ; Heme Oxygenase-1 ; antagonists & inhibitors ; Male ; Mice ; Mice, Inbred BALB C ; Myocarditis ; enzymology ; metabolism ; pathology ; virology ; Myocardium ; pathology ; ultrastructure ; Protoporphyrins ; pharmacology ; Virus Diseases ; metabolism ; pathology

Recent studies demonstrated that brief period of Ca2+ depletion and repletion (Ca2+ preconditioning, CPC) has strong protective effects against ischemia in a rat heart. CPC and classic preconditioning (IPC) were compared in relation with infarct size and protein kinase C (PKC) isozymes. Isolated Langendorff-perfused rabbit hearts were subjected to 45-min ischemia (Isc) followed by 120-min reperfusion (R) with or without IPC, induced by 5-min Isc and 10-min R. In the CPC hearts, 5-min Ca2+ depletion and 10-min repletion (CPC) were given before 45-min Isc, with or without concurrent PKC inhibition (calphostin C, 200 nmol/L). IPC enhanced recovery of LV function, while CPC did not. Infarct size was significantly reduced by both CPC and IPC (p < 0.05 vs. ischemic control). Membrane PKC was significantly increased from 2.53 +/- 0.07 (baseline, nmol/g tissue) to 3.11+/-0.07, 3.34 +/- 0.11, 3.15 +/- 0.09, and 3.06 +/- 0.08 by IPC, IPC and 45-min Isc, CPC and 45-min Isc, respectively (p < 0.01). Immunoblots of membrane PKC were increased by IPC, IPC and 45-min Isc, and CPC. These effects were abolished by PKC inhibition. Thus, activation of PKC may have trigger role in the mechanism of cardioprotective effect by CPC.
Animals ; Calcium/*pharmacology ; Cardiotonic Agents/*pharmacology ; In Vitro ; *Ischemic Preconditioning, Myocardial ; Isoenzymes/metabolism ; L-Lactate Dehydrogenase/metabolism ; Male ; Myocardial Infarction/*pathology ; Myocardium/enzymology/pathology ; Protein Kinase C/metabolism ; Rabbits

OBJECTIVETo investigate whether inhaled sevoflurane is capable of producing delayed cardioprotection effect in rats and its underlying mechanisms.

METHODSMale Sprague-Dawley rats inhaled 1.0 minimum alveolar concentration (MAC) sevoflurane, 1.5 MAC sevoflurane,or O(2) for 1 h. After 24 h and 48 h the left coronary artery of rats was occluded for 30 min,followed by 120 min of reperfusion. Hemodynamics was continuously recorded and myocardial infarct size was determined by Evans blue and triphenyltetrazolium chloride staining. The expression of nitric oxide synthase (NOS) was assessed by immunoblotting.

RESULTS1.0 MAC sevoflurane and 1.5 MAC sevoflurane improved cardiac pump function after reperfusion and reduced myocardial infarct size with the increased iNOS expression (P<0.05). However,the expression of eNOS and p-eNOS was not affected (P>0.05). A selective iNOS inhibitor 1400 W abolished the cardioprotection effect induced by inhalation of 1.0 MAC sevoflurane for 24 h.

CONCLUSIONSevoflurane produces delayed cardioprotection through the up-regulation of iNOS expression.

Anesthetics, Inhalation ; pharmacology ; Animals ; Disease Models, Animal ; Ischemic Preconditioning, Myocardial ; Male ; Methyl Ethers ; pharmacology ; Myocardial Reperfusion Injury ; enzymology ; pathology ; prevention & control ; Myocardium ; enzymology ; pathology ; Nitric Oxide Synthase Type II ; metabolism ; Rats ; Rats, Sprague-Dawley ; Up-Regulation ; drug effects

OBJECTIVETo investigate the inhibitory effect of tetramethylpyrazine (Tet) preconditioning on overload training-induced myocardial apoptosis in rats, and to explore cardioprotective mechanisms of Tet preconditioning.

METHODSA total of 25 male Sprague-Dawley rats were randomly divided into three groups, including the control group (n=5), the overload training group (overload training for 8 weeks, n=10), and the Tet preconditioning group (Tet preconditioning for 8 weeks before overload training, n=10). After 8 weeks, cardiac structure and myocardial apoptosis were analyzed by histology, transmission electron microscopy, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling assay staining. The expressions of Bcl-2, Bax, Caspase-3, and Caspase-9 in myocardium were evaluated by immunohistochemical staining.

RESULTSOverload training caused swelling, disorder, partial rupture, and necrosis of myocardial focal necrotic fibers, as well as mitochondrial vacuolization, cristae rupturing, and blurring. In contrast, Tet preconditioning attenuated the swelling of myocardial fibers, decreased the amount of ruptured fibers, and inhibited mitochondrial vacuolization, resulting in clear cristae. Overload training significantly increased Bax expression and decreased Bcl-2/Bax ratio when compared with the control group (P<0.01). Conversely, Tet preconditioning significantly increased Bcl-2 expression and the Bcl-2/Bax ratio as compared with the overload training group (P<0.05). Overload training dramatically increased the expressions of Caspase-3 and Caspase-9 when compared with the control groupP<0.05). Following Tet preconditioning, the expression of Caspase-3 was significantly reduced compared with the overload training group (P<0.05), while Caspase-9 expression showed a slight decline (P>0.05).

CONCLUSIONTet preconditioning increased the expression of Bcl-2 and reduced the expression of Caspase-3, thereby attenuating overload training-induced myocardial apoptosis, protecting against overload training-induced myocardial injury, and reducing damage to the myocardium due to overload training.

Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Caspase 9 ; metabolism ; Immunohistochemistry ; Male ; Myocardium ; enzymology ; pathology ; ultrastructure ; Pyrazines ; pharmacology ; Rats, Sprague-Dawley ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo evaluate the anti-apoptotic effect of aldehyde dehydrogenase 2 (ALDH2) on myocardial ischemia/reperfusion (I/R) injury in diabetic rats.

METHODSNormal male SD rats were divided into normal, diabetes and ethanol (the agonist of ALDH2) + diabetes groups. In the latter two groups, diabetes was induced by an intraperitoneal injection of 55 mg/kg STZ. Four weeks after the modeling, myocardial I/R was mimicked ex vivo, and lactate dehydrogenase (LDH) content in the coronary flow was determined. The activities of caspase-3 and ALDH2 were evaluated, and the expressions of Bcl-2 and Bax mRNA in the left anterior myocardium were detected using RT-PCR.

RESULTSIn diabetic group, LDH release and caspase-3 activity were increased, while ALDH2 activity and Bcl-2/Bax mRNA expression were decreased as compared to those in normal control group. Compared with the diabetic group, ALDH2 agonist ethanol significantly reduced LDH release and caspase-3 activity, increased ALDH2 activity and Bcl-2/Bax mRNA expression.

CONCLUSIONIn diabetic rats, enhanced ALDH2 expression can offer mycardial protection possibly in relation to suppress cell apoptosis.

Aldehyde Dehydrogenase ; metabolism ; Aldehyde Dehydrogenase, Mitochondrial ; Animals ; Apoptosis ; drug effects ; Caspase 3 ; metabolism ; Diabetes Mellitus, Experimental ; complications ; enzymology ; Ethanol ; pharmacology ; Male ; Mitochondrial Proteins ; agonists ; metabolism ; Myocardial Ischemia ; enzymology ; etiology ; Myocardial Reperfusion Injury ; enzymology ; pathology ; prevention & control ; Myocardium ; enzymology ; pathology ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; bcl-2-Associated X Protein ; metabolism

OBJECTIVETo investigate the effect of hydrogen sulfide-induced delayed preconditioning on glutathione S-transferase (GST) expression during myocardial ischemia-reperfusion in rats.

METHODSSprague-Dawley male rats were randomly divided into 4 groups (n= 10 in each): Group S (sham operation group), Group IR (ischemia/reperfusion group), Group H (IR+ NaHS 0.05 mg/kg iv, 24 h before ischemia) and Groups D receiving IR+NaHS 24 h before ischemia and 5-hydroxydecanoate (5-HD)15 min before ischemia. Animals in groups IR, H and D were subjected to ischemia by 30 min of coronary artery occlusion followed by 2 h of reperfusion. At the end of the reperfusion, myocardial infarct size (IS) was examined. Glutathione S-transferase (GST) was measured by Western blotting. The myocardial ultrastructures were observed under the electron microscopy.

RESULTSThe IS was significantly smaller in Group H than that in Group IR [(25.40 ± 3.54)% compared with (38.27 ± 5.64)%, P<0.05]. The GST expression in myocardium was significantly higher in Group H than that in Group IR. Microscopic examination showed less myocardial damage in Group H than in Group IR. The protective effects of delayed preconditioning by hydrogen sulfide was prevented by 5-HD pre-treatment.

CONCLUSIONThe hydrogen sulfide-induced delayed preconditioning attenuates myocardial IR injury possibly through up-regulating glutathione S-transferase expression in rats.

Animals ; Disease Models, Animal ; Glutathione Transferase ; metabolism ; Hydrogen Sulfide ; administration & dosage ; therapeutic use ; Ischemic Preconditioning, Myocardial ; Male ; Myocardial Reperfusion Injury ; enzymology ; pathology ; therapy ; Myocardium ; enzymology ; ultrastructure ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo observe and compare perioperative myocardial enzyme changes in 107 patients with congenital (CHD, n = 53), rheumatic (RHD, n = 40) and coronary artery (CAD, n = 14) diseases, and to find whether different diseases can affect the release and recovery of myocardial enzymes after heart operations.

METHODSOn the day before operation and the 1st, 3rd, 5th and the 8th day after operation, the venous blood was taken to measure the release of myocardial enzymes: aspartate aminotransferase (AST), creatine kinase (CK), MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase (LDH) and LDH-1.

RESULTSAll the enzymes measured before operation in three groups were in the normal range; their release increased abruptly on the 1st day postoperatively to 2 - 15 times of those before operation; on the 3rd day, they recovered to some degrees, and on the 8th day they recovered to normal in all groups except LDH and LDH-1 in rh and CAD groups. Because the aortic cross-clamp time (CCT) had a good positive correlation to the release of myocardial enzymes, those patients whose CCT was over 60 minutes in three groups were compared revealing that the CCT was not different between three groups (P < 0.05). The release of CK, CK-MB and AST was significantly higher in CHD60 group than those in CHD60 and CAD60 groups, they recovered afterwards; while the release of DH and LDH-1 was higher in CAD60 group than those in CAD60 and in CHD60 groups from the 1st day to the 8th day postoperatively.

CONCLUSIONSThe release of all the 5 enzymes measured before operation was in normal range in selected CHD, RHD and CAD patients. The release peak and the recovery order of all enzymes were the same in three groups. The release of CK, CK-MB and AST was higher in CHD60 group than those in RHD60 and CAD60 groups on the 1st day. The release of LDH and LDH-1 was higher in RHD60 group than those in CHD60 and CAD60 groups from the 1st day to the 8th day postoperatively. The shorter the CCT is, the less the release of myocardial enzymes. Using the release of LDH and LDH-1 to evaluate the recovery of myocardial injury after open-heart operations was recommended.

Adolescent ; Adult ; Aspartate Aminotransferases ; blood ; Child ; Coronary Artery Bypass ; Coronary Artery Disease ; blood ; enzymology ; surgery ; Creatine Kinase ; blood ; Creatine Kinase, MB Form ; blood ; Female ; Heart Defects, Congenital ; blood ; enzymology ; surgery ; Humans ; Intraoperative Period ; Isoenzymes ; blood ; L-Lactate Dehydrogenase ; blood ; Male ; Middle Aged ; Myocardium ; enzymology ; pathology ; Rheumatic Heart Disease ; blood ; enzymology ; surgery ; Time Factors

Recent studies have documented that Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) pathway can modulate the apoptotic program in a myocardial ischemia/reperfusion (I/R) model. To date, however, limited studies have examined the role of JAK3 on myocardial I/R injury. Here, we investigated the potential effects of pharmacological JAK3 inhibition with JANEX-1 in a myocardial I/R model. Mice were subjected to 45 min of ischemia followed by varying periods of reperfusion. JANEX-1 was injected 1 h before ischemia by intraperitoneal injection. Treatment with JANEX-1 significantly decreased plasma creatine kinase and lactate dehydrogenase activities, reduced infarct size, reversed I/R-induced functional deterioration of the myocardium and reduced myocardial apoptosis. Histological analysis revealed an increase in neutrophil and macrophage infiltration within the infarcted area, which was markedly reduced by JANEX-1 treatment. In parallel, in in vitro studies where neutrophils and macrophages were treated with JANEX-1 or isolated from JAK3 knockout mice, there was an impairment in the migration potential toward interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1), respectively. Of note, however, JANEX-1 did not affect the expression of IL-8 and MCP-1 in the myocardium. The pharmacological inhibition of JAK3 might represent an effective approach to reduce inflammation-mediated apoptotic damage initiated by myocardial I/R injury.
Animals ; Apoptosis/drug effects ; Cell Movement/drug effects ; Chemokines/pharmacology ; Heart Function Tests/drug effects ; Inflammation/pathology ; Janus Kinase 3/*antagonists & inhibitors/metabolism ; Macrophages/drug effects/metabolism/pathology ; Male ; Mice ; Mice, Inbred C57BL ; Myocardial Reperfusion Injury/drug therapy/*enzymology/physiopathology/*prevention & control ; Myocardium/enzymology/pathology ; Myocytes, Cardiac/drug effects/metabolism/pathology ; Neutrophils/drug effects/metabolism/pathology ; Quinazolines/pharmacology/therapeutic use