Interferon therapy in hepatitis Cleading to chronic type 1 diabetes

AIM: To review the prevalence,clinical data and course of interferon-associated type 1 diabetes in chronic hepatitis C virus(HCV) infection.METHODS: Search of all interferon(INF)-related type 1diabetes mellitus(T1DM) cases published in the English literature from 1992 to December 2013 according to the key words: chronic hepatitis C infection,diabetes mellitus type 1,insulin dependent diabetes mellitus,and interferon treatment.We found 107 cases and analyzed their clinical and laboratory data and long-term followup.Due to the predominance of cases described in Japanese literature,we analyzed separately cases of Caucasian and Japanese origin.In addition we describe a representative case with HCV who developed INFrelated T1 DM.RESULTS: Our data show that INF treatment increases the risk of developing T1 DM by 10-18 fold compared with the corresponding general population and the median age of onset was 43 years(range: 24-66 years) in Caucasians and 52 years(range: 45-63 years) in Japanese.Most patients developed T1 DM during INF treatment,after a median time-period of 4.2 and 5.7 mo in Caucasian and Japanese groups,respectively.The clinical course was characterized by a fulminant course with abrupt severe hyperglycemia or ketoacidosis,a high titer of anti-islet autoantibodies and almost all patients(105/107) permanently required insulin therapy with a follow-up of up to 4 years.A substantial number of patients had evidence for other autoimmune disorders mainly thyroid diseases(25% and 31% in Caucasian and Japanese groups,respectively).CONCLUSION: INF-associated T1 DM in HCV has a fulminant course,often associated with other autoimmune diseases,and results almost inevitably in permanent insulin therapy requirement.

Metabolic regulation by protein tyrosine phosphatases

Obesity and the metabolic syndrome and their associated morbidities are major public health issues, whose prevalence will continue to increase in the foreseeable future. Aberrant signaling by the receptors for leptin and insulin plays a pivotal role in development of the metabolic syndrome. More complete molecular-level understanding of how both of these key signaling pathways are regulated is essential for full characterization of obesity, the metabolic syndrome, and type lI diabetes, and for developing novel treatments for these diseases. Phosphorylation of proteins on tyrosine residues plays a key role in mediating the effects of leptin and insulin on their target cells. Here, we discuss the molecular methods by which protein tyrosine phosphatases, which are key physiological regulators of protein phosphorylation in vivo, affect signaling by the leptin and insulin receptors in their major target tissues.

Hepatitis C and insulin action:An intimate relationship

Chronic hepatitis C virus(HCV) infection has been shown to be linked to a higher prevalence of type 2 diabetes compared with the general population or with patients with chronic hepatitis B infection and diabetes is the most common extra-hepatic manifestation of HCV. The HCV-diabetes association is due to insulin resistance(IR) that occurs early in the course of the disease even in patients without or with minimal fibrosis. The mechanisms for HCV-induced IR are only partly understood and include a direct inhibitory effect of HCV on insulin signaling pathway. IR in chronic HCV results in an increased progression rate of hepatic fibrosis, cirrhosis and hepatocellular carcinoma. Some but not all studies found that IR reduces the response rate to interferon/ribavirin therapy. Whether IR affects the response to the new direct-acting antiviral treatments is still unknown.