| Theme |
Nonalcoholic Steatohepatitis (NASH) |
| Title |
Cytokines Involved in NASH |
| Author |
Hiromu Kawahara |
Division of Gastroenterology, Department of Internal Medicine, Kanagawa Medical University |
| Author |
Shujiro Takase |
Division of Gastroenterology, Department of Internal Medicine, Kanagawa Medical University |
| [ Summary ] |
Nonalcoholic steatohepatitis (NASH) shows pathologic liver findings similar to alcoholic hepatitis in patients who do not drink alcohol at all. Tumor necrosis factor (TNF)-alpha has been reported to be elevated in the patients with NASH, suggesting several kinds of cytokines may play crucial role in this path ogenesis. TNF-alpha has been known as an original proliferating factor for these cells and an inducer of apoptosis. At the same time, TNF-alpha appears to activate nuclear factor (NF)-kappa B which interrupts apoptosis. Other effects of TNF-alpha have been reported to be increases in insulin resistance and expression of uncoupling protein (UCP)-2 in mitochondria affected by this disease. Animal models of NASH have been proposed for obese rodents, such as ob/ob mice and fa/fa rats, which are leptin dysfunctional. Insulin resistance and upregulation of UCP-2 appear to be obvious in these models. The administration of lipopolysac charide (LPS), increases in interferon r and decrease in interleukin-10, seem to favor of induction of TNF-alpha. Treatment with probiotics or anti-TNF-alpha improves insulin resistance and UCP-2 expression. Histological improvement in the livers of animal models is seen, leading to proposals for new therapies for NASH. |