Published online Jan 28, 2014. doi: 10.3748/wjg.v20.i4.1079
Revised: October 14, 2013
Accepted: November 18, 2013
Published online: January 28, 2014
Processing time: 163 Days and 7.3 Hours
AIM: To investigate the association between endogenous hydrogen sulfide (H2S) and portal hypertension as well as its effect on vascular smooth muscle cells.
METHODS: Portal hypertension patients were categorized by Child-Pugh score based on bilirubin and albumin levels, prothrombin time, ascites and hepatic encephalopathy. Plasma H2S concentrations and portal vein diameters (PVDs) were compared between portal hypertension patients and control participants, as well as between portal hypertension patients with varying degrees of severity. In addition, we established a rabbit hepatic schistosomiasis portal hypertension (SPH) model and analyzed liver morphology, fibrosis grade, plasma and liver tissue H2S concentrations, as well as cystathionine γ-lyase (CSE) activity and phosphorylated extracellular signal-regulated kinase (pERK)1/2, B cell lymphoma (Bcl)-2 and Bcl-XL expression in portal vein smooth muscle cells, in addition to their H2S-induced apoptosis rates.
RESULTS: In portal hypertension patients, endogenous H2S levels were significantly lower than those in healthy controls. The more severe the disease was, the lower were the H2S plasma levels, which were inversely correlated with PVD and Child-Pugh score. Liver tissue H2S concentrations and CSE expression were significantly lower in the SPH rabbit livers compared with the control animals, starting at 3 wk, whereas pERK 1/2 expressions gradually increased 12-20 wk after SPH model establishment. In portal vein smooth muscle cells, increasing H2S levels led to increased apoptosis, while Bcl-2 and Bcl-XL expression decreased.
CONCLUSION: H2S prevents vascular restructuring caused by excessive proliferation of smooth muscle cells via apoptosis induction, which helps to maintain normal vascular structures.
Core tip: In portal hypertension patients, endogenous hydrogen sulfide (H2S) levels were significantly lower than those in healthy controls. H2S plasma level reductions correlated with portal vein diameter and Child-Pugh score. In a rabbit hepatic schistosomiasis portal hypertension model, liver tissue H2S concentrations and cystathionine γ-lyase expression were significantly reduced and phosphorylated extracellular signal regulated kinase 1/2 expression gradually increased. Increasing H2S levels led to increased apoptosis of portal vein smooth muscle cells, while B-cell lymphoma-2 (Bcl-2) and Bcl-XL expression decreased. We suggest that H2S prevents portal hypertension though apoptosis induction of otherwise excessive proliferating smooth muscle cells.