The purpose of this study is to examine the effect of metformin on biochemical and histological findings in NAFLD patients with insulin resistance syndrome.

Study population:

30 patients will be included who meet all the following criteria: ALT > 2 times normal range; liver histology revealing NASH (type 2-4), without cirrhosis; clinical characteristics of the metabolic syndrome as defined by the NCEP, but no overt diabetes; negative work-up for other causes of liver diseases including alcohol intake < 40 g/week.

All patients will undergo liver biopsy and only patients with type 2-4 (steatosis + inflammation, or steatosis plus ballooning degeneration, or steatosis plus fibrosis and/or Mallory bodies) but without cirrhosis will be included.

Patients who received lipid lowering medications or anti hypertensive drugs prior to study will continue the treatment. Patients who will develop overt type 2 DM with HbAic > 7% during study will be withdrawn.

Intervention:

All patients will have dietary intervention by a dietician and will be encouraged to increase physical activity. Patients will be receiving metformin 850 mg tid for 12 months.

Outcome:

• Improvement of liver enzymes (ALT, AST, GGT)
• Improvement of metabolic profile: lipid profile, fasting and post-load glucose and insulin levels, HOMA.
• Liver histology (repeated liver biopsy after 1 year).
• Soluble TNF receptors- TNF-receptor P55 and P75.

Inclusion Criteria:

• ALT > 2 times normal range.
• Liver histology revealing non-alcoholic steatohepatitis [NASH] (type 2-4), without cirrhosis.
• Clinical characteristics of the metabolic syndrome as defined by the National Cholesterol Education Program (NCEP), but no overt diabetes.
• Negative work-up for other causes of liver diseases including alcohol intake < 40 g/week.

Exclusion Criteria:

• Diabetes mellitus.
• Alcohol intake > 40 g per week.