Serum osteopontin levels as a predictor of portal inflammation in patients with nonalcoholic fatty liver disease

Abstract

Background: Osteopontin is a secreted phosphorylated glycoprotein that is expressed by a variety of cell types and that mediates numerous and diverse biological functions. Osteopontin knockout mice are protected from obesity-induced hepatic steatosis. In the present study, we sought to investigate whether serum osteopontin concentrations are associated with liver histology in patients with nonalcoholic fatty liver disease.

Methods: Serum levels of osteopontin were measured by enzyme-linked immunosorbent assay in 179 well-characterized patients with nonalcoholic fatty liver referred for liver histology and 123 control subjects.

Results: Serum osteopontin levels were markedly higher in patients with nonalcoholic fatty liver disease than in controls (p<0.001). Multivariable analysis showed that osteopontin levels were strongly and independently associated with both portal inflammation (β=0.294, p<0.01) and serum aminotransferase levels (aspartate aminotransferase: β=0.295, p<0.01; alanine aminotransferase; β=0.285, p<0.01).

Conclusion: In summary, these data demonstrate that serum levels of osteopontin are elevated in nonalcoholic fatty liver disease and are a significant independent predictor of portal inflammation in this clinical entity.