Study On The Expression Of Enos And Hsp90 In The Wall Of Splenic Veins In Patients With Portal Hypertension

Background & ObjectivePortal hypertension (PHT) is a common clinical syndrome characterized by a pathological increase in portal pressure. It is often present in patients with chronic liver diseases. In PHT, high blood pressure and high blood flow constitute a special hemodynamic state in the portal venous system. Stress (the force of unit area) can be induced by pressure and flow. It has been suggested that an overproduction of endogenous nitric oxide (NO) could be involved in the hyperdynamic circulation and portal hypertension vasculopathy (PHV). NO is a potent vasodilator that activates soluble guanylate cyclase (sGC), leading to the generation of cyclic guanosine monophosphate (cGMP), which mediates various functions including smooth muscle relaxation. Endothelial nitric oxide synthase (eNOS) is an important enzyme responsible for NO production. Excessive production of NO, a consequence of eNOS overexpression, could play an important role in the pathogenesis of PHT. The regulation of eNOS is a process containing eNOS transcription, translocation, protein interaction and phosphorylation. Heat shock protein is a set of proteins having general and important biological functions, such as cell growth, development and adjusting process as molecular chaperones. Heat shock protein 90 (Hsp90), which is one of the heat shock protein family, is an important regulatory protein. There are contradictory reports whether the expression of eNOS is up-regulated in vascular of patients with PHT. It is necessary to study the effect of Hsp90 and eNOS in PHT. The present study is designed to investigate the expression of Hsp90 and eNOS in splenic vein of patients with PHT and the relationship between them. We look forward to find the role of Hsp90 and eNOS in the pathogenesis of PHT.MethodsSplenic veins from patients with PHT (n=27, PHT group) were removed during pericardial vascular devascularization with splenectomy, while normal splenic veins were from splenic rupture (n=10, control group). Samples from splenic veins were examined by HE staining. All of them were observed under optic microscopes. The expression of Hsp90 and eNOS proteins in the splenic veins of patients with PHT and normal control were analysed with immunohistochemistry. Pearson correlation analysis was used to evaluate the relationship between the expression of Hsp90 and eNOS in patients with PHT.Results1. HE staining: Thickness of the intima of splenic veins in patients with PHT increased remarkably compared with control group. Endothelial cells integrated with the formation of mimicked arteriosclerosis plaques. The tunica media thickened significantly because of hypertrophy of smooth muscle. Fiber and connective tissues increased.2. Immunohistochemical staining: The positive signal for Hsp90 and eNOS were observed in the cytoplasm. The Hsp90 and eNOS expression in endothelial cells in splenic vein of patients with PHT showed positive or strongly positive signal, and positive signal of Hsp90 was also observed in some smooth muscle cells in these specimens. In the control group, staining was negative or weakly positive.3. The intensity of integral optical density (IOD) of Hsp90 and eNOS in patients with PHT were significantly higher than that in control group (P < 0.01). The IOD of Hsp90 in splenic vein of patients with PHT is 0.18±0.03 while it is 0.09±0.02 in the control. The IOD of eNOS in splenic vein of PHT group is 0.19±0.03 while it is 0.08±0.02 in the control. The SUM of Hsp90 and eNOS in patients with PHT were significantly higher than that in control group (P< 0.01). The SUM of Hsp90 in splenic vein of patients with PHT is 20.76±3.41 while it is 10.80±2.15 in the control. The SUM of eNOS in splenic vein of PHT group is 21.37±2.39 while it is 9.68±1.85 in the control.4. Pearson correlation analysis showed that the expression of Hsp90 protein in splenic vein of patients with PHT was positively correlated with eNOS protein (r=0.727, P<0.01).5. The expression of eNOS and Hsp90 was increased associated with the aggravation of Child-pugh types of liver function.Conclusions1. The expression of eNOS and Hsp90 in the splenic vein of patients with PHT are higher than those in control group. It showes that eNOS and Hsp90 may participate in the occurrence and development of PHT.2. There is a positive correlation between the expression of eNOS and Hsp90 protein. They may work in coordination to sustain the state of portal hypertension, and they may show a collaborative interaction effect.3. The expression of eNOS and Hsp90 in splenic vein has no correlation with the patients's age and agenda. The expression level rises with the worsening of liver function.4. The inhibition of Hsp90, which can decrease the activity of eNOS and production of NO, may be a specific and effective method for the therapy of PHT.