Ravalli S, Albala A, Ming M, Szabolcs M, Barbone A, Michler R E, Cannon P J
Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
Circulation. 1998 Jun 16;97(23):2338-45. doi: 10.1161/01.cir.97.23.2338.
The inducible isoform of the nitric oxide synthase (iNOS) produces large amounts of nitric oxide in response to cytokine stimulation. Previous investigations have demonstrated iNOS expression in the setting of acute and chronic rejection in experimental cardiac transplant models. The goal of this study was to investigate whether iNOS is upregulated in human transplant coronary artery disease (TCAD), a major cause of late mortality after cardiac transplantation.
We studied 15 patients with TCAD and 10 with normal coronary arteries. In situ hybridization and immunohistochemistry were used in tissue sections to localize iNOS mRNA and protein, respectively. The presence of peroxynitrite was indirectly assessed by immunostaining with an anti-nitrotyrosine antibody. Normal coronary arteries had no evidence of iNOS expression. In contrast, 30 of 36 coronary artery segments with TCAD (83%) were immunostained by the iNOS antibody. The presence of iNOS mRNA was demonstrated in these vessels by in situ hybridization. Specific cell markers identified iNOS-positive cells as neointimal macrophages and smooth muscle cells. Nitrotyrosine immunoreactivity colocalized with iNOS expression in arteries with TCAD, distributed in macrophages and smooth muscle cells.
iNOS mRNA and protein are expressed in human arteries with TCAD, where they are associated with extensive nitration of protein tyrosines. These findings indicate that the high-output nitric oxide pathway and possibly the oxidant peroxynitrite might be involved in the process leading to the development of TCAD.
一氧化氮合酶（iNOS）的诱导型同工型在细胞因子刺激下会产生大量一氧化氮。先前的研究已证实在实验性心脏移植模型的急性和慢性排斥反应中存在iNOS表达。本研究的目的是调查在心脏移植术后晚期死亡的主要原因——人类移植冠状动脉疾病（TCAD）中iNOS是否上调。
我们研究了15例TCAD患者和10例冠状动脉正常的患者。分别使用原位杂交和免疫组化技术在组织切片中定位iNOS mRNA和蛋白。通过用抗硝基酪氨酸抗体进行免疫染色间接评估过氧亚硝酸盐的存在。正常冠状动脉无iNOS表达的证据。相比之下，36个TCAD冠状动脉节段中有30个（83%）被iNOS抗体免疫染色。通过原位杂交在这些血管中证实了iNOS mRNA的存在。特定细胞标志物将iNOS阳性细胞鉴定为内膜巨噬细胞和平滑肌细胞。在TCAD动脉中，硝基酪氨酸免疫反应性与iNOS表达共定位，分布于巨噬细胞和平滑肌细胞中。
iNOS mRNA和蛋白在患有TCAD的人类动脉中表达，在那里它们与蛋白质酪氨酸的广泛硝化有关。这些发现表明，高输出一氧化氮途径以及可能的氧化剂过氧亚硝酸盐可能参与了导致TCAD发生的过程。
