Zahler S, Kupatt C, Möbert J, Becker B F, Gerlach E
Department of Physiology, University of Munich, Munich, Germany.
J Mol Cell Cardiol. 1997 Nov;29(11):2953-60. doi: 10.1006/jmcc.1997.0530.
Redox stress during post-ischemic reperfusion may be the prime signal for processes leading to myocardial remodelling and hypertrophy. Nitric oxide (NO) is antioxidative, antiadhesive for neutrophils (PMN) and antiproliferative. Thus, enhancing endothelial production of NO, e.g. by inhibiting breakdown of endogenous bradykinin via angiotensin converting enzyme (ACE), could be beneficial. The effect of cilazaprilat (CILA, 10 micro M), an ACE inhibitor, on redox status, expression of the adhesion molecule P-selectin, and PMN adhesion under conditions of oxidative stress was investigated in cultured human umbilical vein endothelial cells (HUVECs). Incubation of the cells with H2O2 (0.1 and 1 mm) for 15 min served as oxidative stimulus. The intra- and extracellular concentrations of reduced and oxidized glutathione (GSH and GSSG) were measured by HPLC as indicators of endothelial redox status. Expression of P-selectin was measured by flow cytometry. Furthermore, firm leukocyte adhesion to HUVECs was assessed. In controls, the intracellular ratio GSH/GSSG averaged 47 and dropped to 30 after incubation with 0.1 mm H2O2. The ratio declined to 6.5 with 1 mm H2O2. CILA blocked the effects of 0.1 mm H2O2, but was ineffective against 1 mm peroxide. The extracellular ratio did not discriminate between 0.1 and 1 mm H2O2, falling from 18 to 1 in both situations. P-selectin expression rose from 100% (control) to 146% after 1 mm H2O2 without CILA, but only to 114% in the presence of CILA. PMN adhesion was enhanced from about 1600 PMN per microwell (control) to 4300/well by 1 mm H2O2. CILA had no significant effect on adhesion (3900 PMN/well). Exposure of HUVECs to 0.1 mm H2O2 affected neither P-selectin expression nor PMN adhesion. Consequently, ACE inhibition can mitigate mild (0.1 mm H2O2) but not more severe redox stress in HUVECs. Irrespectively, CILA reduced the upregulation of P-selectin at the higher H2O2 concentration, indicating that this process is regulated independently of the cellular redox status. The firm adhesion of PMN to HUVECs was independent of P-selectin expression.
缺血后再灌注期间的氧化还原应激可能是导致心肌重塑和肥大过程的主要信号。一氧化氮（NO）具有抗氧化、对中性粒细胞（PMN）抗黏附及抗增殖作用。因此，增强内皮细胞产生NO，例如通过抑制内源性缓激肽经血管紧张素转换酶（ACE）的降解，可能有益。研究了ACE抑制剂西拉普利拉（CILA，10微摩尔）对氧化应激条件下培养的人脐静脉内皮细胞（HUVECs）氧化还原状态、黏附分子P-选择素表达及PMN黏附的影响。用H2O2（0.1和1毫摩尔）孵育人脐静脉内皮细胞15分钟作为氧化刺激。通过高效液相色谱法测定还原型和氧化型谷胱甘肽（GSH和GSSG）的细胞内和细胞外浓度，作为内皮细胞氧化还原状态的指标。通过流式细胞术测定P-选择素的表达。此外，评估白细胞对人脐静脉内皮细胞的牢固黏附。在对照组中，细胞内GSH/GSSG比值平均为47，用0.1毫摩尔H2O2孵育后降至30。用1毫摩尔H2O2孵育后，该比值降至6.5。西拉普利拉可阻断0.1毫摩尔H2O2的作用，但对1毫摩尔过氧化物无效。细胞外比值在0.1和1毫摩尔H2O2之间无差异，在两种情况下均从18降至1。在无西拉普利拉时，1毫摩尔H2O2后P-选择素表达从100%（对照）升至146%，但在有西拉普利拉时仅升至114%。1毫摩尔H2O2使PMN黏附从每微孔约1600个PMN（对照）增至4300个/微孔。西拉普利拉对黏附无显著影响（3900个PMN/微孔）。人脐静脉内皮细胞暴露于0.1毫摩尔H2O2对P-选择素表达和PMN黏附均无影响。因此，ACE抑制可减轻人脐静脉内皮细胞中的轻度（0.1毫摩尔H2O2）而非更严重的氧化还原应激。无论如何，西拉普利拉在较高H2O2浓度下可减少P-选择素的上调，表明该过程的调节独立于细胞氧化还原状态。PMN对人脐静脉内皮细胞的牢固黏附独立于P-选择素表达。
