Hafizi S, Chester A H, Allen S P, Morgan K, Yacoub M H
Department of Cardiothoracic Surgery, National Heart and Lung Institute, Imperial College School of Medicine, Harefield Hospital, Middlesex, UK.
Coron Artery Dis. 1998;9(4):167-75. doi: 10.1097/00019501-199809040-00001.
The renin-angiotensin system has been implicated in the development of vascular wall thickening in cardiovascular disease, through the growth-promoting actions of the vasoconstrictive agent, angiotensin II, on vascular smooth muscle cells.
To investigate the effect of angiotensin II on growth of human coronary artery smooth muscle cells (cSMCs) in culture, and to identify the angiotensin receptor(s) mediating such a response.
Human cSMCs were isolated from coronary arteries of recipient hearts obtained during transplantation, and characterized by immunohistochemistry. The effect of angiotensin II on protein synthesis by cSMCs was measured by [3H]leucine incorporation and protein concentration assays. Human cSMC proliferation was assessed by [3H]thymidine incorporation assay and cell count. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect angiotensin receptor expression. Transient increases in intracellular calcium concentration in cSMCs in response to angiotensin II stimulation were visualized under fura-2 fluorescence microscopy.
Angiotensin II (1 nmol/l-10 mumol/l) stimulated protein synthesis in cSMCs (maximum 24 +/- 2% increase in incorporation of [3H]leucine over 48 h; n = 4, P < 0.01). An increase in cellular protein content was also measured. However, angiotensin II had no effect on proliferation of quiescent cSMCs. The increased protein synthesis was completely inhibited by pretreatment with the angiotensin AT1 receptor antagonist, losartan, but not the AT2 receptor antagonist, PD123319. Expression of the angiotensin AT1 receptor subtype was detected in cSMCs by RT-PCR. Angiotensin II stimulation of cells triggered transient increases in intracellular calcium concentration, which were abolished by losartan, but were insensitive to PD123319 and pertussis toxin.
The results of this study in human coronary VSMCs indicate that angiotensin II and the AT1 receptor may be involved in the development of coronary artery disease in man.
肾素 - 血管紧张素系统通过血管收缩剂血管紧张素II对血管平滑肌细胞的促生长作用，与心血管疾病中血管壁增厚的发展有关。
研究血管紧张素II对培养的人冠状动脉平滑肌细胞（cSMC）生长的影响，并确定介导这种反应的血管紧张素受体。
从移植过程中获得的受体心脏冠状动脉中分离出人cSMC，并通过免疫组织化学进行鉴定。通过[3H]亮氨酸掺入和蛋白质浓度测定来测量血管紧张素II对cSMC蛋白质合成的影响。通过[3H]胸苷掺入测定和细胞计数评估人cSMC增殖。逆转录聚合酶链反应（RT-PCR）用于检测血管紧张素受体表达。在fura-2荧光显微镜下观察血管紧张素II刺激后cSMC细胞内钙浓度的瞬时增加。
血管紧张素II（1 nmol/l - 10 μmol/l）刺激cSMC中的蛋白质合成（48小时内[3H]亮氨酸掺入量最大增加24±2％；n = 4，P <0.01）。还测量了细胞蛋白质含量的增加。然而，血管紧张素II对静止cSMC的增殖没有影响。用血管紧张素AT1受体拮抗剂氯沙坦预处理可完全抑制蛋白质合成的增加，但AT2受体拮抗剂PD123319则不能。通过RT-PCR在cSMC中检测到血管紧张素AT1受体亚型的表达。血管紧张素II刺激细胞引发细胞内钙浓度的瞬时增加，氯沙坦可消除这种增加，但对PD123319和百日咳毒素不敏感。
这项在人冠状动脉VSMC中的研究结果表明，血管紧张素II和AT1受体可能参与人类冠状动脉疾病的发展。
