Department of Surgical and Gastroenterological Sciences, University of Padua, Via Giustiniani, 2, 35128 Padua, Italy.
J Gastroenterol. 2010;45(1):68-76. doi: 10.1007/s00535-009-0122-y.
The endocannabinoid system (EC) has emerged as a crucial mediator in a variety of pathophysiological conditions.
To evaluate: (1) whether the EC system is activated in the livers of patients with primary biliary cirrhosis (PBC); (2) if genetic variations in human EC receptor genes (CB1 and CB2) may be associated with a different phenotypic expression of the disease and response to therapy.
The expression of CB1 and CB2 receptors was studied by immunohistochemistry in liver biopsy specimens from 13 patients with PBC, and CB1 and CB2 mRNA expression was studied by real-time polymerase chain reaction testing (RT-PCR) in liver samples. In addition, genetic polymorphisms in the EC receptor gene were sought in 68 patients with PBC from Italy, 84 patients who were residents of the United States (US), and 70 controls matched for sex, age, and for geographical area with the Italian PBC patients. Genomic DNA was extracted from peripheral venous blood leucocytes with standard methods. PCR was used to amplify the coding regions of the CB1 and CB2 genes with specific primers.
CB1 was markedly expressed in hepatocytes and biliary epithelial cells in the livers of patients with PBC; conversely in control liver samples, it was virtually absent. CB2 was expressed in hepatocytes and in cholangiocytes, whereas it was absent from mesenchymal cells. The mRNA of both CB1 and CB2 was detected in the PBC liver samples, as demonstrated by RT-PCR. The CB1 polymorphism (1359 G/A) was present in 26.5% of Italian patients, in 22.9% of healthy controls, and in 27.4% of patients from the US (p = n.s.). The CB2 polymorphism (188-189 AA/GG) was present in 24.4 versus 30.4% of Italian and US patients with PBC, respectively, and in 28.0% of Italian controls samples (p = n.s.). Logistic regression analysis showed that advanced histological stage and the lack of response to ursodeoxycholic acid treatment were significantly correlated with the CB1 polymorphism.
The EC system is markedly up-regulated in the livers of patients with PBC and it may exert a role regulating adaptive mechanisms in cholestasis.
内源性大麻素系统（EC）已成为多种病理生理条件的关键介质。
评估：（1）原发性胆汁性肝硬化（PBC）患者的肝脏中 EC 系统是否被激活；（2）如果人类 EC 受体基因（CB1 和 CB2）的遗传变异是否可能与疾病的不同表型表达和对治疗的反应相关。
通过免疫组织化学研究 13 例 PBC 患者肝活检标本中 CB1 和 CB2 受体的表达，并通过实时聚合酶链反应（RT-PCR）检测肝组织中 CB1 和 CB2 mRNA 的表达。此外，还在来自意大利的 68 例 PBC 患者、84 例居住在美国的患者和 70 例与意大利 PBC 患者在性别、年龄和地理位置上相匹配的对照者中寻找 EC 受体基因的遗传多态性。使用标准方法从外周静脉血白细胞中提取基因组 DNA。PCR 用于使用特异性引物扩增 CB1 和 CB2 基因的编码区。
PBC 患者肝脏中 CB1 在肝细胞和胆管上皮细胞中明显表达；相反，在对照肝组织中几乎不存在。CB2 在肝细胞和胆管细胞中表达，而在间质细胞中不存在。通过 RT-PCR 检测到 PBC 肝组织中 CB1 和 CB2 的 mRNA。CB1 多态性（1359 G/A）在 26.5%的意大利患者、22.9%的健康对照者和 27.4%的美国患者中存在（p = 无显著性差异）。CB2 多态性（188-189 AA/GG）分别在 24.4%和 30.4%的意大利和美国 PBC 患者以及 28.0%的意大利对照者中存在（p = 无显著性差异）。逻辑回归分析显示，组织学晚期和对熊去氧胆酸治疗无反应与 CB1 多态性显著相关。
EC 系统在 PBC 患者的肝脏中明显上调，可能在调节胆汁淤积的适应性机制中发挥作用。
