Caveolin-1 is critical for hepatic iron storage capacity in the development of nonalcoholic fatty liver disease.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is associated with disordered lipid and iron metabolism. Our previous study has substantiated the pivotal role of Caveolin-1 (Cav-1) in protecting hepatocytes and mediating iron metabolism in the liver. This study aimed to explore the specific mechanisms underlying the regulation of iron metabolism by Cav-1 in NAFLD. METHODS: Hepatocyte-specific Cav-1 overexpression mice and knockout mice were used in this study. Cav-1-knockdown of RAW264.7 cells and mouse primary hepatocytes were performed to verify the changes in vitro. Moreover, a high-fat diet and palmitic acid plus oleic acid treatment were utilized to construct a NAFLD model in vivo and in vitro, respectively, while a high-iron diet was used to construct an in vivo iron overload model. Besides, iron concentration, the expression of Cav-1 and iron metabolism-related proteins in liver tissue or serum were detected using iron assay kit, Prussian blue staining, Western blotting, immunofluorescence staining, immunohistochemical staining and ELISA. The related indicators of lipid metabolism and oxidative stress were evaluated by the corresponding reagent kit and staining. RESULTS: Significant disorder of lipid and iron metabolism occurred in NAFLD. The expression of Cav-1 was decreased in NAFLD hepatocytes (P < 0.05), accompanied by iron metabolism disorder. Cav-1 enhanced the iron storage capacity of hepatocytes by activating the ferritin light chain/ferritin heavy chain pathway in NAFLD, subsequently alleviating the oxidative stress induced by excess ferrous ions in the liver. Further, CD68+CD163+ macrophages expressing Cav-1 were found to accelerate iron accumulation in the liver, which was contrary to the effect of Cav-1 in hepatocytes. Positive correlations were also observed between the serum Cav-1 concentration and the serum iron-related protein levels in NAFLD patients and healthy volunteers (P < 0.05). CONCLUSIONS: These findings confirm that Cav-1 is an essential target protein that regulates iron and lipid metabolic homeostasis. It is a pivotal molecule for predicting and protecting against the development of NAFLD.

Long-term follow-up of cumulative incidence of hepatocellular carcinoma in hepatitis B virus patients without antiviral therapy.

BACKGROUND: China has a high prevalence of hepatitis B virus (HBV), but most chronic hepatitis B (CHB) patients do not receive standardized antiviral therapy. There are few relevant reports addressing the outcomes of the large number of CHB patients who do not receive antiviral therapy. AIM: To observe the outcomes of long-term follow-up of patients with CHB without antiviral treatment. METHODS: This study included 362 patients with CHB and 96 with hepatitis B cirrhosis without antiviral treatment and with only liver protection and anti-inflammatory treatment from 1993 to 1998. The median follow-up times were 10 and 7 years, respectively. A total of 203 CHB and 129 hepatitis B cirrhosis patients receiving antiviral therapy were selected as the control groups. The median follow-up times were 8 and 7 years, respectively. Kaplan-Meier curves were used to analyze the cumulative incidence of hepatocellular carcinoma (HCC), and the Cox regression model was used to analyze the risk factors for HCC. RESULTS: Among the patients in the non-antiviral group, 16.9% had spontaneous decreases in HBV DNA to undetectable levels, and 32.8% showed hepatitis B e antigen (HBeAg) seroconversion. In the antiviral group, 87.2% of patients had undetectable HBV DNA, and 52% showed HBeAg seroconversion. Among CHB and hepatitis B cirrhosis patients, the cumulative incidence rates of HCC were 14.9% and 53.1%, respectively, in the non-antiviral group and were 10.7% and 31.9%, respectively, in the antiviral group. There was no difference between the two groups regarding the CHB patients (P = 0.842), but there was a difference between the groups regarding the hepatitis B cirrhosis patients (P = 0.026). The cumulative incidence rates of HCC were 1.6% and 22.3% (P = 0.022) in the groups with and without spontaneous HBeAg seroconversion, respectively. The incidence rates of HCC among patients with and without spontaneous declines in HBV DNA to undetectable levels were 1.6% and 19.1%, respectively (P = 0.051). There was no difference in the cumulative incidence of HCC between the two groups regarding the patients with drug-resistant CHB (P = 0.119), but there was a significant difference between the two groups regarding the patients with cirrhosis (P = 0.004). The Cox regression model was used for regression of the corrected REACH-B score, which showed that alanine aminotransferase > 400 U/L, history of diabetes, and family history of liver cancer were risk factors for HCC among men aged > 40 years (P < 0.05). Multifactorial analysis showed that a family history of HCC among men was a risk factor for HCC. CONCLUSION: Antiviral therapy and non-antiviral therapy with liver protection and anti-inflammatory therapy can reduce the risk of HCC. Antiviral therapy may mask the spontaneous serological response of some patients during CHB. Therefore, the effect of early antiviral therapy on reducing the incidence of HCC cannot be overestimated.

Clinical and histopathological features of chronic hepatitis B virus infected patients with high HBV-DNA viral load and normal alanine aminotransferase level: A multicentre-based study in China.

BACKGROUND: The aim of this study is to reveal the clinical and histopathological features of HBsAg-positive and HBeAg-positive chronic hepatitis B infected patients with high level of HBV DNA, from 17 hospitals and medical centres in China, with alanine aminotransferase levels within the lower region of normal range versus those with levels within the upper region of normal range and to investigate the clinical risk factors for the requirement of treatment through the examination of liver biopsy. METHODS: Liver biopsy was performed on high level of HBV DNA of 455 patients with HBsAg-positive and HBeAg-positive chronic hepatitis B infection and persistently normal alanine aminotransferase level. Liver necroinflammation and fibrosis were graded per the Knodell histological activity index and Ishak's fibrosis score, respectively. Univariate analysis of the clinical parameters versus necroinflammation and fibrosis was carried out. RESULTS: Of the subjects in this multicentre-based study, 5.49% and 10.11% had significant necroinflammation with Knodell histological activity index ≥ 9 and hepatic fibrosis stages with Ishak scores ≥ 3, respectively. The subjects were stratified into three age groups (30-39, 40-49 and ≥ 50 years), and our data clearly suggested that age, particularly in the age group over 50, was an independent predictor of liver necroinflammation and fibrosis. Lower HBV-DNA viral levels were found in patients with Knodell histological activity index ≥ 9 or advanced fibrosis (Ishak scores ≥ 3). CONCLUSION: Our results showed that histological changes in liver tissues were observed in a significant proportion of patients with persistently normal alanine aminotransferase level. According to the data evaluation results, liver biopsy is advisable for HBeAg-positive chronic hepatitis B infected patients aged older than 40 and high HBV-DNA viral load in China.