摘要
目的:观察难治性高血压患者血清中血管紧张素1型受体(AT1)的自身抗体对大鼠主动脉血管平滑肌细胞(VSMC)细胞质游离钙水平的影响。方法:应用AT1的胞外第2环作为抗原,采用ELISA方法检测22例难治性高血压患者血清中AT1自身抗体,提纯难治性高血压患者血清中的AT1自身抗体。用细胞免疫荧光染色方法检测该抗体与AT1的亲和性。培养大鼠主动脉VSMC,应用钙离子的荧光探针Fluo-3/AM负载原代VSMC,应用共聚焦显微镜检测细胞荧光强度变化来反映细胞内游离钙水平的变化。将该患者血清、提纯AT1自身抗体、血管紧张素Ⅱ(AngⅡ)分别作用于VSMC,观察荧光强度变化来检测VSMC细胞质游离钙水平变化。结果:22例难治性高血压患者中有10例(45.5%)患者AT1自身抗体阳性,明显高于非难治高血压组(12.5%,P<0.05)。提纯的AT1自身抗体能够与VSMC膜表面AT1特异性结合。并且该抗体能够刺激VSMC,使得胞内游离钙水平增高。该抗体具有与AngⅡ类似激动效应,并能够被AT1拮抗剂洛沙坦阻断。结论:AT1胞外第2环肽的抗体能够与AT1特异结合并且模拟AngⅡ的激动作用,促进VSMC胞内游离钙水平升高,在难治性高血压患者高血压发病机制中起着重要作用。应用AT1拮抗剂洛沙坦能够有效地阻断该抗体的效应。
Objective： To explore the effect of autoantibodies against AT1 receptor of patients with refractory hypertension on the intracellular Ca^2＋ mobilization in vascular smooth muscle cells （VSMC）. Method：Forty-six patients with hypertension were recruited and divided into two groups based on whether their blood pressure was above or below 140/90 mmHg after combination drug therapy： a refractory hypertension group （n=22） and a nonrefractory hypertension group （n= 24）. The epitope of the second extracellular loop of AT1 receptor was synthesized and used as antigen to screen the antibodies by ELISA. IgG from patients with the refractory hypertension was obtained by affinity purification, and was used to prove the affinity with AT1-receptor in the cultured vascular smooth muscles （VSMC） by immunocytochemistry. Then, Fluo-3/AM, a Ca^2＋ fluorescent indicator was used to load VSMC. IgG from patients was used to stimulate VSMC and the change of fluorescence was monitored by confocal microscopy. Result.. Frequency of the autoantibodies against AT1 receptor in refractory hypertension group was higher than that in non-refractory hypertension group （P〈0.05）. And VSMC showed increased intracelluar Ca^2＋ mobilization induced by the patients＇ antibodies against AT1 receptor. Furthermore, we found the autoantibody-induced Ca^2＋ increase could be blocked by losartan, an AT1 receptor antagonist. Conclusion： Antibodies against AT1 receptor with the ability to activate AT1 receptor may account for Ca^2＋ increase in VSMC. And the autoantibodies may involve in the pathogenesis of hypertension, especially in patients refractory to drug treatment.
出处
《临床心血管病杂志》
CAS
CSCD
北大核心
2007年第9期674-678,共5页
Journal of Clinical Cardiology
基金
国家自然科学基金资助(No:G30300133)
