Janciauskiene S, Gerbord M C, Lindgren S
Department of Medicine, University Hospital Malmö, Sweden.
J Hepatol. 1998 Oct;29(4):541-9. doi: 10.1016/s0168-8278(98)80148-7.
BACKGROUND/AIMS: The serine proteinase inhibitors (serpins), alpha-1-antitrypsin (AAT) and alpha-1-antichymotrypsin (ACT), are acute phase proteins synthesized by hepatocytes and excreted to some extent into bile. Their role in gallstone pathogenesis is unclear, and it was the aim of this study to determine their effect on cholesterol crystal growth rate in model bile.
Purified AAT and ACT were added to model bile at concentrations from 0.5 to 500 microg/ml. Cholesterol crystal growth was analyzed daily by polarizing microscopy and spectrophotometrically at 650 nm. Serpin inhibitory activity was measured spectrophotometrically at 405 nm, and polymerization was studied on 7.5% SDS-PAGE under non-reducing conditions, by immunoelectrophoresis and Western blotting.
ACT added to model bile at a concentration of 0.5 microg/ml, inhibited cholesterol crystallization by 30%, had no influence at 5 microg/ml, and increased the crystallization rate 2-3 fold at concentrations of 50 and 500 microg/ml. AAT at a concentration of 0.5 microg/ml had a profound (50%) inhibitory effect on cholesterol crystal growth rate, lacked significant effect at both concentrations of 5 and 50 microg/ml, and showed stimulation of crystal growth up to 30% at a concentration of 500 microg/ml. Both serpins incubated in model bile polymerized and totally lost their inhibitory activity.
Serpins can exhibit both inhibiting and promoting effects on the cholesterol crystallization rate in model bile, dependent on their concentrations. Since AAT and ACT are acute phase proteins, their concentrations may vary under certain pathological conditions, which may result in different actions of these serpins in gallstone formation.
背景/目的：丝氨酸蛋白酶抑制剂（丝氨酸蛋白酶抑制剂），α-1-抗胰蛋白酶（AAT）和α-1-抗糜蛋白酶（ACT），是由肝细胞合成并在一定程度上排泄到胆汁中的急性期蛋白。它们在胆结石发病机制中的作用尚不清楚，本研究的目的是确定它们对模型胆汁中胆固醇晶体生长速率的影响。
将纯化的AAT和ACT以0.5至500μg/ml的浓度添加到模型胆汁中。每天通过偏光显微镜和在650nm处的分光光度法分析胆固醇晶体的生长。通过分光光度法在405nm处测量丝氨酸蛋白酶抑制剂的抑制活性，并在非还原条件下在7.5％SDS-PAGE上通过免疫电泳和蛋白质印迹研究聚合。
以0.5μg/ml的浓度添加到模型胆汁中的ACT抑制胆固醇结晶30％，在5μg/ml时无影响，在50和500μg/ml的浓度下使结晶速率增加2-3倍。浓度为0.5μg/ml的AAT对胆固醇晶体生长速率具有显著（50％）的抑制作用，在5和50μg/ml的浓度下均无显著影响，并且在500μg/ml的浓度下显示出高达30％的晶体生长刺激。在模型胆汁中孵育的两种丝氨酸蛋白酶抑制剂均发生聚合并完全丧失其抑制活性。
丝氨酸蛋白酶抑制剂对模型胆汁中胆固醇结晶速率可表现出抑制和促进作用，这取决于它们的浓度。由于AAT和ACT是急性期蛋白，它们的浓度在某些病理条件下可能会发生变化，这可能导致这些丝氨酸蛋白酶抑制剂在胆结石形成中产生不同的作用。
