Sex-related influence of angiotensin-converting enzyme polymorphisms on fibrosis progression due to recurrent hepatitis C after liver transplantation

Hepatitis C recurrence: the Achilles heel of liver transplantation

Hepatitis C virus (HCV) infection is the most common indication for liver transplantation worldwide; however, recurrence post transplant is almost universal and follows an accelerated course. Around 30% of patients develop aggressive HCV recurrence, leading to rapid fibrosis progression (RFP) and culminating in liver failure and either death or retransplantation. Despite many advances in our knowledge of clinical risks for HCV RFP, we are still unable to accurately predict those most at risk of adverse outcomes, and no clear consensus exists on the best approach to management. This review presents a critical overview of clinical factors shown to influence the course of HCV recurrence post transplant, with particular focus on recent data identifying the important role of metabolic factors, such as insulin resistance, in HCV recurrence. Emerging data for genetic markers of HCV recurrence and their usefulness for predicting adverse outcomes will also be explored.

Theoretical basis of a beneficial role for vitamin D in viral hepatitis

Abnormal bone metabolism and dysfunction of the calcium-parathyroid hormone-vitamin D axis have been reported in patients with viral hepatitis. Some studies suggested a relationship between vitamin D and viral hepatitis. Genetic studies have provided an opportunity to identify the proteins that link vitamin D to the pathology of viral hepatitis (i.e., the major histocompatibility complex class II molecules, the vitamin D receptor, cytochrome P₄₅₀, the renin-angiotensin system, apolipoprotein E, liver X receptor, toll-like receptor, and the proteins regulated by the Sp1 promoter gene). Vitamin D also exerts its effects on viral hepatitis via non-genomic factors, i.e., matrix metalloproteinase, endothelial vascular growth factor, prostaglandins, cyclooxygenase-2, and oxidative stress. In conclusion, vitamin D could have a beneficial role in viral hepatitis. Calcitriol is best used for viral hepatitis because it is the active form of the vitamin D₃ metabolite.

Mild alcohol consumption is not associated with increased fibrosis in patients with chronic hepatitis C

BACKGROUND

Excessive alcohol consumption is associated with an increased risk for fibrosis progression and cirrhosis in patients with chronic hepatitis C virus (HCV) infection. However, the impact of mild-moderate alcohol use on the severity of liver fibrosis is unclear.

GOALS

The objective of this retrospective study was to assess the impact of mild alcohol consumption on liver fibrosis in patients with chronic HCV.

STUDY

857 patients with well-characterized chronic HCV were enrolled. All underwent liver biopsy to assess hepatic fibrosis. The duration of HCV infection was determined by detailed questionnaires and personal interviews. Alcohol use history was estimated by the Skinner Alcohol Examination Questionnaire. Mild alcohol use was defined as 1 to 3 alcoholic beverages/day (<30 grams/d). Participants were divided into 4 groups based on their average lifetime daily alcohol consumption (essentially none, <1, 1 to 3 or >3 drinks/d) and into quartiles based on their presumed duration of HCV infection (<23, 23 to 31, 31 to 38, or >38 y).

RESULTS

Mean alcohol consumption was 2.7 drinks/d; mean duration of HCV infection was 29 years. Daily alcohol consumption was not significantly higher among participants with advanced fibrosis (bridging fibrosis or cirrhosis) when compared with those with none or portal fibrosis (3.2 vs. 2.2 drinks/d, respectively, P=NS). The degree of fibrosis increased significantly with the duration of HCV infection (P<0.0001) and was independent of mild-moderate alcohol consumption.

CONCLUSIONS

Mild alcohol use does not seem to adversely affect the severity of fibrosis in patients with chronic HCV.

Cytokines and renin-angiotensin system signaling in hepatic fibrosis

Hepatic fibrosis is the result of a complex interplay between resident hepatic cells, infiltrating inflammatory cells, and a number of locally acting peptides called cytokines. Key mediators include transforming growth factor b1, vasoactive substances, adipokines, inflammatory cytokines and chemokines. Angiotensin II, the main effector of the renin-angiotensin system, is a true cytokine that plays a major role in liver fibrosis. Angiotensin II is locally synthesized in the injured liver and induces profibrogenic actions in hepatic stellate cells. Drugs blocking the renin-angiotensin system are promising antifibrotic agents. There are multiple signal transduction pathways involved in cytokine signaling. Drugs interfering intracellular pathways involved in increased collagen production are potential therapies for liver fibrosis.