Dong Nianguo

Effect of L-carnitine on cardiomyocyte apoptosis and cardiac function in patients undergoing heart valve replacement operation.

SummaryThe effects of L-carnitine, as an ingredient of cardioplegia solution, on cardiac function and cardiomyocyte apoptosis in patients undergoing heart valve replacement operation were investigated. Twenty-three cases undergoing heart valve replacement with cardiopulmonary bypass (CPB) were randomly allocated into two groups: L-carnitine group (n=12, 12 g/L L-carnitine was put in the ST. Thomas cardioplegia) and control group (n=11, identical to the L-carnitine group except that normal saline was administered instead of L-carnitine). Serum cardial troponin I (cTnI) levels, the left ventricular ejection fraction (LVEF), and cardiac index (CI) were measured perioperatively. A bit of myocardial tissue obtained from right atria was taken before CPB and by the end of intracardiac procedure to undergo electron microscopy examination and estimate apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL). From the end of CPB to 3 days after operation, the serum levels of cTnI in the L-carnitine group was significantly lower than that in the control group (P<0.05). Heart color ultrasonogram showed that the CI index and LVEF at 7th day postoperatively in the L-carnitine group were significantly higher than in the control group (P<0.05). Compared to the control group, L-carnitine significantly alleviated the morphologic changes of cardiac muscle cells (electron microscopy examination) and decreased the amounts of apoptotic cardiac muscle cells (TUNEL). Furthermore, the dosage of vasoactive drugs used after operation was significantly less in the L-carnitine group (P<0.01). It was concluded that L-carnitine cardioplegia solution could improve cardiac function in patients undergoing heart valve replacement operation and alleviate CPB-mediated apoptosis of cardiac muscle cells.

Influence of transplantation of allogenic bone marrow mononuclear cells on the left ventricular remodeling of rat after acute myocardial infarction

To probe into the influence of transplantation of allogenic bone marrow mononuclear cells (BM-MNCs) on the left ventricular remodeling of rat after acute myocardial infarction (AMI), 60 male Wistar rats were evenly divided into three groups at random: control group 1, control group 2 and transplantation group. In control group 1, chest was opened without ligation of coronary artery; in control group 2 and transplantation group, the left anterior descending branch of coronary artery was ligated to establish AMI model. Prepared culture medium and allogenic BM-MNCs suspension were respectively implanted the surrounding area of infracted cardiac muscle via epicardium of control group 2 and transplantation group. Four weeks after the operation, the osteopontin gene (OPN mRNA, P<0.01), type collagen (P<0.01) and angiotensin (Ang, P<0.01) content in the left ventricular non-infracted myocardium, and the Ang density in blood plasma (P<0.05) of transplantation group and control group 2 were all significantly higher than that of control group 1. In the transplantation group, the myocardial OPN mRNA, type I collagen and Ang II content of non-infracted zone in left ventricle, and the Ang II concentration in blood plasma were all significantly lower than those of control group 2 (P<0.05 for all). It is concluded that allogenic BM-MNCs transplantation may ease left ventricular remodeling after AMI by inhibiting the synthesis of type I collagen in the cardiac muscle and down-regulating the expression of Ang II and OPN gene.

Acidic HEPES-KH Reperfusion Enhances Myocardial Protection in Immature Rabbits

SummaryTo study the effects of different pH HEPES-KH reperfusate solution on immature myocardial protection, isolated perfused Langendorff model from immature rabbit hearts were developed formed. Control group (C) was perfused only with pH 7.4 HEPES-KH solution for 90 min. Ischemia/reperfusion group (group I/R) was perfused with pH 7.4 HEPES-KH solution before ischemia or after ischemia. Experimental group (group E), after ischemia,w as perfused with pH 6. 8, pH 7. 1 and pH7. 4 HEPES-KH solutions for 5 min, 5 min, and 20 min, respectively. The left ventricular function recovery, MWC, LDH and CK leakage, MDA, ATP content, and SOD activity were determined. Our results showed that the left ventricular function recovery, ATP content and SOD activity in group E were higher than those of group I/R (P<0.05). MWC, MDA content, LDH and CK leakage in group E were lower than those of group I/R (P<0.05). There findings suggested that pH paradox might be one of important mechanisms for immature myocardial ischemiareperfusion injury, and acidic perfusate, at the beginning of reperfusion, might attenuate pH paradox and ameliorate functional recovery in isolated perfused immature rabbit hearts.