Yuko Wakisaka

BACKGROUND: Inflammatory cytokines have been reported to contribute to the progression of cardiac remodeling in various heart diseases and a remarkable prolongation of the monophasic action potential duration and reductions in the expression of Kv4.2 and K+ channel-interacting protein-2 (KChIP-2) in a rat autoimmune myocarditis model have been documented. In this study, the effect of tumor necrosis factor-alpha (TNF-alpha) on cultured cardiomyocytes was evaluated, focusing on the change in the voltage-gated outward K+ current and expression of related molecules. METHODS AND RESULTS: Cardiomyocytes isolated from 1-day-old Lewis rats were cultured for 72 h and treated with TNF-alpha (50 ng/ml) for an additional 48 h. The myocytes treated with TNF-alpha showed a 22% reduction in the peak K+ current, which consisted of a transient outward K+ current (Ito) and 1.4-fold enhancement of the cell-capacitance in comparison with the control. Among the cardiac ion channel related molecules evaluated in this study, Kv4.2 and KChIP-2 mRNA exhibited remarkable reductions (p < 0.05). CONCLUSIONS: Treatment with TNF-alpha induced reductions in Ito as well as cellular hypertrophy in neonatal cultured myocytes, which indicates that TNF-alpha might play a role in promoting electrical remodeling of cardiomyocytes under inflammatory conditions.

BACKGROUND: Although saphenous vein grafts (SVG) have been used from 1975 to treat coronary stenosis caused by Kawasaki disease, long-term results after more than 20 years remain unknown. METHODS AND RESULTS: From 1981 to 1997, 13 patients underwent coronary artery bypass grafting using SVG (n=20). The age at operation ranged from 2 to 20 years (median 11 years), the age at latest angiography from 15 to 36 years (median 30 years) and the postoperative follow-up period was from 10 to 26 years (median 22 years). The patency rate of the SVG was determined by postoperative angiography, graft wall morphology was graded and the late clinical course was reviewed. The patency rates at 1, 10, and 25 years after operation were 84.4%, 57.2%, and 51.5%, respectively. Irregularity of the SVG wall was slight in 3 of 7 patients with long-term patency. One patient with obesity and hyperlipidemia underwent stent implantation in the SVG because of graft stenosis. CONCLUSION: Although the patency rates for SVG are low, there are patients with long-term patency over 20 years. Obesity and hyperlipidemia in these patients should be vigorously pursued.