Significance of serum and hepatic microRNA-122 levels in patients with non-alcoholic fatty liver disease
Hisamistu Miyaaki, Tatsuki Ichikawa, Naoto Taura, Satoshi Miuma, Hidetaka Shibata, Takuya Honda, Kazuhika Nakao
The First Department of Internal Medicine, Nagasaki University School of Medicine, Nagasaki, Japan
Aims: Non-alcoholic fatty liver disease (NAFLD) is thought to be a type of metabolic syndrome. MicroRNA-122 (miR-122) is the most abundant microRNA in the liver and is an important factor for the metabolism of glucose and lipids. In this study, we examined the correlation of hepatic and serum miR-122 expression levels with the clinicopathological factors of patients with NAFLD. Methods: Total RNA with preserved miRNAs was extracted from liver biopsy samples of 67 patients with NAFLD. In 52 of these 67 patients, total RNA was extracted from serum. miR-122 obtained by quantitative reverse transcription-polymerase chain reaction was quantified using TaqMan MicroRNA assays. MiR-122 expression was calculated by the relative standard curve method and normalized to RNU6 in the liver and cell-miR39 expression in the serum. Results: A significantly correlation was detected between serum and hepatic miR-122 expression (correlation coefficient, 0.461; p = 0.005). Patients with mild steatosis (<33%) showed significantly lower levels of hepatic miR-122 than patients with severe steatosis (>33%) (hepatic miR-122: mild: severe = 2.158 ± 1.786: 4.836 ± 7.506, p = 0.0473; serum miR-122: mild: severe = 0.002 ± 0.005: 0.007 ± 0.001, p = 0.0491). There was no significant correlation of hepatic and serum miR-122 and NAFLD Activity score (NAS). However, hepatic and serum miR-122 levels in liver showed significantly inverse correlation of fibrosis stage [Hepatic miR-122: correlation coefficient −0.292, p =0.0161; Serum miR-122: correlation coefficient −0.316, p =0.021 8]. Moreover, hepatic and serum miR-122 levels were significantly higher in patients with mild fibrosis than in those with severe fibrosis (hepatic miR-122: mild: severe = 5.201 ± 7.275: 2.394 ± 1.547, p = 0.0087; serum miR122: mild: severe = 0.008 ± 0.011: 0.002 ± 0.004, p = 0.0191). Conclusions: Hepatic and serum miR-122 levels were associated with hepatic steatosis and fibrosis. Serum miR-122 level was well correlated with hepatic miR-122 and could be a useful predictive marker of liver fibrosis.
The following people have nothing to disclose: Hisamistu Miyaaki, Īatsuki Ichikawa, Naota Taura, Satoshi Miuma, Hidetaka Shibata, Takuya Honda, Kazuhiko Nakao