Low Vitamin D Levels Impair HCV Response to Interferon
NEW YORK (Reuters Health) – Patients with chronic hepatitis C virus (HCV) infection have lower serum levels of 25-hydroxyvitamin D than healthy individuals, and as their vitamin D level falls, so does the likelihood of a sustained virologic response to interferon and ribavirin, new research shows.
Disturbances in vitamin D metabolism can affect the inflammatory response and fibrogenesis, Dr. Salvatore Petta, from the University of Palermo, Italy, and co-researchers state. Exactly how vitamin D levels influence the progression of chronic hepatitis C and response to treatment, however, was not known, according to the report in the November 15th issue of Hepatology.
To investigate this topic, the researchers analyzed data from 197 patients with biopsy-proven genotype 1 chronic hepatitis C and from 49 healthy matched controls. Most of the patients (n=167) were treated with peg-interferon and ribavirin. Tissue expression of two liver 25-hydroxylating enzymes, CYP27A1 and CYP2R1, was evaluated in 34 patients and 8 controls.
Average serum levels of 25-hydroxyvitamin D were 25.1 mcg/L in patients and 43.1 mcg/L in controls (p < 0.001). Significant correlates of lower levels included female gender and necroinflammation. Expression of CYP27A1, but not CYP2R1, was directly linked to the level of 25-hydroxyvitamin D and inversely related to necroinflammation. On multivariate analysis, low 25-hydroxyvitamin D levels, low cholesterol levels, older age, high ferritin, and necroinflammation were all independent predictors of severe fibrosis. Seventy patients (42%) treated with interferon and ribavirin achieved a sustained virologic response. Hepatic steatosis and lower levels of 25-hydroxyvitamin D and cholesterol predicted that patients would not achieve a sustained response. "This study, showing low levels of serum 25-hydroxyvitamin D and of their hydroxylating enzymes in genotype 1 chronic hepatitis C patients, and suggesting a relation of vitamin D status with the severity of liver disease and response to therapy, opens a new area of research on the potential use of vitamin D in patients with chronic hepatitis C," the authors conclude. Hepatology 2009. click here read aritical