Megumi Shimada

Interleukin-6/soluble interleukin-6 receptor complex reduces infarct size via inhibiting myocardial apoptosis.

Apoptosis of cardiomyocytes plays an important role in reperfusion injury following myocardial infarction. Conversely, interleukin-6 (IL-6)—a potent cytokine—inhibits myeloma cell apoptosis by activating GP130 through the IL-6 receptor (IL-6R). We hypothesized that the IL-6/soluble IL-6R complex can inhibit myocardial apoptosis, and limit infarct size in reperfused acute myocardial infarction. Anesthetized rats were randomly divided into five groups: sham, coronary occlusion and reperfusion rats administered IL-6/soluble IL-6R complex, IL-6 alone, soluble IL-6R (sIL-6R) alone, or a control vehicle. Rats were subjected to 30 min occlusion of the left coronary artery followed by 3 h reperfusion. After reperfusion, the hearts were excised. For detection and quantification of apoptosis, gel electrophoresis of extracted genomic DNA and TUNEL method of paraffin sections were performed. The percentage of the infarct area was measured using tetrazolium chloride staining. The cardiomyocyte apoptosis analysis revealed that apoptosis in the reperfused myocardium was inhibited only in the complex group. Furthermore, the percentage of the infarct area out of the area at risk was remarkably reduced in the complex group (23.8±1.8%), compared with that in the vehicle (37.9±3.7%), the IL-6 (40.7±1.0%), or the sIL-6R (37.5±2.4%) groups (P=0.0002). No significant differences were observed among the vehicle, IL-6, and sIL-6R groups. The IL-6/soluble IL-6 receptor complex inhibits cardiomyocyte apoptosis in reperfused acute myocardial infarction. It possibly reduces irreversible reperfusion injury.

The EAT/mcl-1 gene, an inhibitor of apoptosis, is up-regulated in the early stage of acute myocardial infarction

EAT/mcl-1 (EAT), a bcl-2-related immediate early gene, is up-regulated at an early stage of differentiation of human embryonal carcinoma cells. Recent studies have revealed that EAT inhibits apoptosis both in vitro and in vivo. In the present study, we demonstrated that the EAT gene was up-regulated in the early stage of rat myocardial infarction. This pattern of up-regulation was apparently different from that of another immediate early gene, c-fos. EAT, an anti-apoptotic molecule, was strongly up-regulated in the non-ischemic region. In contrast, the expression of c-fos was induced in both ischemic and non-ischemic regions, and was higher in the ischemic region. Apoptosis of cardiomyocytes is currently thought to significantly contribute to acute myocardial infarction. We detected cardiomyocyte apoptosis by gel electrophoresis of genomic DNA and in situ nick end labeling in the ischemic region, but not in the non-ischemic region. As an inhibitor of apoptosis, EAT may play a role in the protection of cardiomyocytes in the early stage of acute myocardial infarction.

Effects of early reperfusion on creatine kinase release in patients with acute myocardial infarction: implications for reperfusion injury.

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A case of CREST syndrome associated with sick sinus syndrome.

Cardiac manifestations of the CREST syndrome or limited systemic sclerosis (ISSc) are very rare. We report a case of CREST syndrome associated with sick sinus syndrome. Histopathology of cardiac muscle revealed fibrotic changes, suggesting that such changes may be pathogenetically related to CREST syndrome.