胰腺局部肾素-血管紧张素系统的生理作用

全身肾素-血管紧张素系统(RAS)在调节血压及水、电解质平衡方面起重要作用。而最近发现多种组织、器官中存在局部独立的RAS,在局部自分泌、旁分泌等生理功能方面起不同程度的作用。目前发现在胰腺组织内,包括胰腺腺泡、导管、胰岛、上皮细胞以及星形细胞中存在局部RAS,在生理和包括低氧、胰腺炎、胰岛移植、糖尿病等病理刺激条件下,其表达发生相应改变。RAS在胰腺内、外分泌功能中起重要作用:调节局部血流、导管细胞分泌碳酸氢钠、腺泡细胞分泌消化酶、胰岛β细胞合成及释放胰岛素、δ细胞分泌生长抑素、胰腺细胞增殖和分化。此外,还可能介导氧化应激诱导的细胞炎症、凋亡和纤维化。通过上述影响,胰腺局部RAS在胰腺炎、糖尿病、囊性纤维化及胰腺肿瘤的形成中可能起一定的作用,本文就胰腺局部RAS的生理功能及临床意义进行综述。

Physiological Function of Local Renin - Angiotensin System in the Pancreas

The renin-angiotensin system(RAS)plays an important role in regulating blood pressure,fluid and electrolyte homeostasis.However,local RASs also exist in diverse tissues and organs,where they play roles to deferent degree in physiological functions of autocrine and paracrine.The existence of local RAS is now recognized in pancreatic acinar,islet,duct,endothelial and stellate cells.Their expressions are modulated in response to physiological and pathophysiological stimuli such as hypoxia,pancreatitis,islet transplantation and diabetes mellitus.The pancreatic RASs have important roles of endocrine and exocrine in the pancreas such as regulating local blood flow,sodium bicarbonate secretion by duct cell,digestive enzyme secretion by acinar cell,(pro)insulin biosynthesis by islet beta-cell and insulin release,somatostatin secretion by delta-cell and pancreatic cell proliferation and differentiation.Besides,they may also mediate oxidative stress-induced cell inflammation,apoptosis and fibrosis.By the above mechanisms RASs probably take part in the pathogeneses of pancreatitis,diabetes,cystic fibrosis and pancreatic cancer.New therapeutic targets and strategies might thus be suggested.