Several
past studies have reported an association between chronic
hepatitis C virus (HCV) infection and a higher risk of insulin
resistance, a condition in which cells do not respond normally to insulin,
leading to impaired glucose metabolism. Over time, insulin resistance can progress
to frank type 2 diabetes.
As
reported in the January 11, 2007 electronic edition of the American Journal
of Gastroenterology, Japanese researchers assessed the effect of anti-HCV
therapy and HCV
clearance on insulin resistance, beta-cell function, and expression in the
liver of insulin receptor substrate (IRS)1/2, key molecules involved in insulin
signaling.
The
investigators analyzed data from 89 patients with biopsy-proven chronic HCV infection.
Patients received interferon-alpha, with or without ribavirin, for 6 months. They
were classified into 3 groups at 6 months after the completion of antiviral therapy
according to response:
Insulin
resistance and beta-cell function were assessed using the homeostasis model assessment
method (HOMA-IR and HOMA-%B, respectively). Hepatic expression of IRS1/2 in 14
sustained responders was evaluated using immunoblotting and immunostaining.
Results
•
In non-responders
and relapsers, there were no significant changes in HOMA-IR or HOMA-%B values
after completion of antiviral therapy.
•
In sustained responders,
however, HOMA-IR values significantly decreased, from 3.1 to 1.7 after antiviral
therapy (P < 0.05).
•
Similarly, HOMA-%B
values significantly decreased from 113.7 to 90.6 (P < 0.05).
•
Immunoblotting showed
a 3-fold increase in IRS1/2 expression after HCV clearance.
•
Immunostaining revealed
greater IRS1/2 expression in hepatocytes.
Conclusion
In
conclusion, the authors wrote, "We showed that clearance of HCV improves
insulin resistance, beta-cell function, and hepatic IRS1/2 expression."
These
data indicate that in addition to halting liver disease progression and reducing
the development of liver cirrhosis
and hepatocellular carcinoma,
successful insulin-based therapy can also improve metabolic abnormalities, which
in turn may reduce the risk of cardiovascular disease.
02/06/07
Reference T
Kawaguchi, T Ide, E Taniguchi, and others. Clearance of HCV Improves Insulin Resistance,
Beta-Cell Function, and Hepatic Expression of Insulin Receptor Substrate 1 and
2. American Journal of Gastroenterology. January 11, 2007 [Epub ahead of
print].
