Sorafenib targets dysregulated Rho kinase expression and portal hypertension in rats with secondary biliary cirrhosis

Background and purpose

Extrahepatic vasodilation and increased intrahepatic vascular resistance represent attractive targets for the medical treatment of portal hypertension in liver cirrhosis. In both dysfunctions, dysregulation of the contraction-mediating Rho kinase plays an important role as it contributes to altered vasoconstrictor responsiveness. However, the mechanisms of vascular Rho kinase dysregulation in cirrhosis are insufficiently understood. They possibly involve mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK)-dependent mechanisms in extrahepatic vessels. As the multikinase inhibitor sorafenib inhibits ERK, we tested the effect of sorafenib on haemodynamics and dysregulated vascular Rho kinase in rats with secondary biliary cirrhosis.

Experimental approach

Secondary biliary cirrhosis was induced by bile duct ligation (BDL). Sorafenib was given orally for 1 week (60 mg·kg⁻¹·d⁻¹). Messenger RNA levels were determined by quantitative real time polymerase chain reaction, protein expressions and protein phosphorylation by Western blot analysis. Aortic contractility was studied by myographic measurements, and intrahepatic vasoregulation by using livers perfused in situ. In vivo, haemodynamic parameters were assessed invasively in combination with coloured microspheres.

Key results

In BDL rats, treatment with sorafenib decreased portal pressure, paralleled by decreases in hepatic Rho kinase expression and Rho kinase-mediated intrahepatic vascular resistance. In aortas from BDL rats, sorafenib caused up-regulation of Rho kinase and an improvement of aortic contractility. By contrast, mesenteric Rho kinase remained unaffected by sorafenib.

Conclusions and implications

Intrahepatic dysregulation of vascular Rho kinase expression is controlled by sorafenib-sensitive mechanisms in rats with secondary biliary cirrhosis. Thus, sorafenib reduced portal pressure without affecting systemic blood pressure.     

2，4－二氨基5－氟－6－取代苄氨基喹唑啉的合成及生物活性

本文报道２，４－二氨基－５－氟－６－取代苄氨基喹唑啉类化合物的合成及抗疟、抗肿瘤和抗菌活性，这类化合物的合成是由５－氟－２，４，６－三氨基喹唑啉（６ａ）与取代苯甲醛缩合成Ｓｃｈｉｆｆ碱，然后经还原、甲酰化、亚硝化或甲基化制得。５－氟－２，４，６－三氨基喹唑啉（６ａ）尚未见文献报道，由５－氟－２，４－二氨基喹唑啉（４）经硝化生成异构体５ａ和５ｂ分离得５ａ后再经还原制得。经对伯氏鼠疟原虫Ｐｌａｓｍｏｄｉｕｍｂｅｒｇｈｅｉ抑制性治疗筛选，有６个化合物Ｉ２，４．５，６和ＩＩ５，６以每日１ｍｇ·ｋｇ－１，给药４天，抑制率为１００％；体外抗肿瘤活性以Ｉ４最强，对Ｌ１２１０白血病细胞的ＩＣ５０为９．８６×１０－４μｇ·ｍｌ－１，优于氨甲蝶呤（ＭＴＸ）；经对１８种常见菌进行体外筛选，发现对肺炎双球菌Ｄｉｐｌｏｃｏｃｃｕｓｐｎｅｕｍｏｎｉａｅ活性较好。