Ikeda Keiichi, Tojo Katsuyoshi, Udagawa Takashi, Otsubo Chikara, Ishikawa Masahiro, Tokudome Goro, Hosoya Tatsuo, Tajima Naoko, Nakao Kazuwa, Kawamura Masahiro
Department of Pharmacology, Jikei University School of Medicine, Tokyo, Japan.
Hypertens Res. 2008 Apr;31(4):693-706. doi: 10.1291/hypres.31.693.
An understanding of the cellular physiology of cardiac myocytes (MCs) and non-myocytes (NMCs) may help to explain the mechanisms underlying cardiac hypertrophy. Despite numerous studies using MC/NMC co-culture systems, it is difficult to precisely evaluate the influence of each cell type because of the inherent cellular heterogeneity of such a system. Here we developed a co-culture system using Wistar rat neonatal MCs and NMCs isolated by discontinuous Percoll gradient and adhesion separation methods and cultured on either side of insert well membranes. Co-culture of MCs and NMCs resulted in significant increases in [3H]-leucine incorporation by MCs, in the amount of protein synthesized by MCs, and in the secretion of natriuretic peptides, while the addition of MCs to NMC cultures significantly reduced [3H]-thymidine incorporation by NMCs. Interestingly, the percentage of the brain natriuretic peptide (BNP) component of total natriuretic peptide secreted (atrial natriuretic peptide+BNP) increased as the number of NMCs placed in the MC/NMC co-culture system increased. However, MCs did not affect production of angiotensin II (Ang II) by NMCs or secretion of endothelin-1 and transforming growth factor-beta1 into the MC/NMC co-culture system. This finding was supported by the anti-hypertrophic and anti-fibrotic actions of RNH6270, an active form of olmesartan, on MCs in the MC/NMC co-culture system and on NMCs that may synthesize Ang II in the heart. The present data indicate that cardiac fibrosis may not only facilitate MC hypertrophy (possibly through the local angiotensin system) but may also change particular pathophysiological properties of MCs, such as the secretory pattern of natriuretic peptides.
了解心肌细胞（MCs）和非心肌细胞（NMCs）的细胞生理学，可能有助于解释心肌肥大的潜在机制。尽管使用MC/NMC共培养系统进行了大量研究，但由于该系统固有的细胞异质性，难以精确评估每种细胞类型的影响。在此，我们开发了一种共培养系统，使用通过不连续 Percoll 梯度和粘附分离方法分离的 Wistar 大鼠新生MCs和NMCs，并在插入孔膜的两侧进行培养。MCs和NMCs的共培养导致MCs的[3H]-亮氨酸掺入量、MCs合成的蛋白质量以及利钠肽分泌量显著增加，而将MCs添加到NMC培养物中显著降低了NMCs的[3H]-胸苷掺入量。有趣的是，随着放置在MC/NMC共培养系统中的NMCs数量增加，分泌的总利钠肽（心房利钠肽+脑钠肽）中脑钠肽（BNP）成分的百分比增加。然而，MCs不影响NMCs产生血管紧张素II（Ang II），也不影响内皮素-1和转化生长因子-β1分泌到MC/NMC共培养系统中。奥美沙坦的活性形式RNH6270对MC/NMC共培养系统中的MCs以及心脏中可能合成Ang II的NMCs具有抗肥大和抗纤维化作用，这一发现支持了上述结果。目前的数据表明，心脏纤维化不仅可能促进MC肥大（可能通过局部血管紧张素系统），还可能改变MCs的特定病理生理特性，如利钠肽的分泌模式。
