Studies on the mechanism of cardiotoxicity of methamphetamine using coculture of isolated cardiomyocytes and non-myocytes.

2003 Fiscal Year Final Research Report Summary

• Project/Area Number: 13670432
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Legal medicine
• Research Institution: Nagoya City University
• Principal Investigator: MAENO Yoshitaka Nagoya City University, Graduate School of Medical Sciences, Associate Professor, 大学院・医学研究科, 助教授 (00145749)
• Co-Investigator(Kenkyū-buntansha): ISOBE Ichiro Nagoya City University, Graduate School of Medical Sciences, Research Associate, 大学院・医学研究科, 助手 (30315907)
• Project Period (FY): 2001 – 2003
• Keywords: Cardiotoxicity / Coculture / Cardiomyocyte / Cardiovascular endothelial cell / Microtubule / Methamphetamine / p-methoxyamphetamine / 4-methylthioamphetamine

Research Abstract

The direct effect of methamphetamine (MA) on cardiac lesion seen in MA abusers was studied by use of an experimental model of isolated adult rat cardiac myocytes (ARCs) and cardiovascular endothelial cells (CVECs). Recently, we have reported that chronic exposure to a high concentration of MA might directly inhibit development of ARCs in culture and that a continuous exposure to a low concentration of MA might facilitate the development of cellular hypertrophy. The aim of this study was to investigate whether the presence of CVECs influenced MA-induced morphological changes of ARCs in culture. When CVECs were exposed to 0.5 mM MA, the granule-like structures were remarkably observed around nucleus on 4 days after exposure using a phase contrast microscopy. In addition, immunoreactive microtubules were more abundant and the microtubules-orgnizing center-like structure was clearly seen in the central part of MA-treated CVEC. These changes reversible. In order to evaluate the morphological change of MA-treated CVEC, the cells were also exposed to p-methoxyamphetamine (PMA) and 4-methylthio-amphetamine (4-MTA), amphetamine analogues. The morphological changes of PMA-treated CVCEs were similar to MA treatment. In 4-MTA treatment, CVCEs including abundant granule-like structures decreased in spreading area and increased in thickness of the cell, and aggregation of F-actin fibers was localized to the periphery of the cell. Therefore, these findings may be a common phenomenon between amphetamine analogues. Furthermore, as coculture experiments of CVEC and ARC treated with MA, cultured ARCs were exposed to conditioned medium in which CVECs were attenuated, while phosphorylation of intracellular MAP kinase was enhanced. In conclusion, these results indicate that MA induces morphological changes of CVEC and CVECs treated with MA may release factor(s) to attenuate spreading area of ARCs.