No abstract

The mechanisms for progressive fibrosis and exacerbation by steatosis in patients with chronic hepatitis C (HCV) are still unknown. We hypothesized that proliferative blockade in HCVinfected and steatotic hepatocytes results in the default activation of hepatic progenitor cells (HPC), capable of differentiating into both biliary and hepatocyte lineages, and that the resultant ductular reaction promotes portal fibrosis. To study this concept, 115 liver biopsy specimens from subjects with HCV were scored for steatosis, inflammation, and fibrosis. Biliary epithelium and HPC were decorated by cytokeratin 7 immunoperoxidase, and the replicative state of hepatocytes was assessed by p21 and Ki-67 immunohistochemistry. A ductular reaction at the portal interface was common. There was a highly significant correlation between the area of ductular reaction and fibrosis stage (r ‫؍‬ 0.453, P < .0001), which remained independently associated after multivariate analysis. HPC numbers also correlated with fibrosis (r ‫؍‬ 0.544, P < .0001) and the ductular area (r ‫؍‬ 0.624, P < .0001). Moreover, steatosis correlated with greater HPC proliferation (r ‫؍‬ 0.372, P ‫؍‬ .0004) and ductular reaction (r ‫؍‬ 0.374, P < .0001) but was not an obligate feature. Impaired hepatocyte replication by p21 expression was independently associated with HPC expansion (P ‫؍‬ .002) and increased with the body mass index (P < .001) and lobular inflammation (P ‫؍‬ .005). In conclusion, the strong correlation between portal fibrosis and a periportal ductular reaction with HPC expansion, the exacerbation by steatosis, and the associations with impaired hepatocyte replication suggest that an altered regeneration pathway drives the ductular reaction. We believe this triggers fibrosis at the portal tract interface. This may be a stereotyped response of importance in other chronic liver diseases. (HEPATOLOGY 2005;41: 809-818.)

Background: Interferon a (IFN-a) activated cellular signalling is negatively regulated by inhibitory factors, including the suppressor of cytokine signalling (SOCS) family. The effects of host factors such as obesity on hepatic expression of these inhibitory factors in subjects with chronic hepatitis C virus (HCV) are unknown. Objectives: To assess the independent effects of obesity, insulin resistance, and steatosis on response to IFN-a therapy and to determine hepatic expression of factors inhibiting IFN-a signalling in obese and nonobese subjects with chronic HCV. Methods: A total of 145 subjects were analysed to determine host factors associated with non-response to antiviral therapy. Treatment comprised IFN-a or peginterferon alpha, either alone or in combination with ribavirin. In a separate cohort of 73 patients, real time-polymerase chain reaction was performed to analyse hepatic mRNA expression. Immunohistochemistry for SOCS-3 was performed on liver biopsy samples from 38 patients with viral genotype 1 who had received antiviral treatment. Results: Non-response (NR) to treatment occurred in 55% of patients with HCV genotypes 1 or 4 and 22% with genotypes 2 or 3. Factors independently associated with NR were viral genotype 1/4 (p,0.001), cirrhosis on pretreatment biopsy (p = 0.025), and body mass index > 30 kg/m 2 (p = 0.010). Obese subjects with viral genotype 1 had increased hepatic mRNA expression of phosphoenolpyruvate carboxy kinase (p = 0.01) and SOCS-3 (p = 0.047), in comparison with lean subjects. Following multivariate analysis, SOCS-3 mRNA expression remained independently associated with obesity (p = 0.023). SOCS-3 immunoreactivity was significantly increased in obesity (p = 0.013) and in non-responders compared with responders (p = 0.014). Conclusions: In patients with chronic HCV viral genotype 1, increased expression of factors that inhibit interferon signalling may be one mechanism by which obesity reduces the biological response to IFN-a.

Background-Kidney disease alters the pharmacokinetic disposition of many medications, requiring dosage adjustment to maintain therapeutic serum concentrations. The Cockcroft-Gault equation is used for pharmacokinetic studies and drug dosage adjustments, but the MDRD Study equation is more accurate and more often reported by clinical laboratories than the Cockcroft-Gault equation.