Nonalcoholic fatty liver disease (NAFLD) patients with diabetes constitute a subgroup of patients with a high rate of liver-related complications. Currently, there are no specific drug recommendations for these patients. Metformin, a conventional insulin sensitizer agent, has been widely prescribed in patients with diabetes. Metformin treatment has been shown to be effective at alleviating hepatic lipogenesis in animal models of NAFLD, with a variety of mechanisms being deemed responsible. To date, most studies have enrolled diabetic patients who are treated with metformin, with the drug being taken continuously throughout the study. Although evidence exists regarding the benefits of metformin for NAFLD in preclinical studies, reports on the efficacy of metformin in adult NAFLD patients have had some discrepancies regarding changes in liver biochemistry and hepatic fat content. Evidence has also suggested possible effects of metformin as regards the prevention of hepatocellular carcinoma tumorigenesis. This review was performed to comprehensively summarize the available in vitro, in vivo and clinical studies regarding the effects of metformin on liver steatosis for the treatment of adult NAFLD patients with diabetes. Consistent reports as well as controversial findings are included in this review, and the mechanistic insights are also provided. In addition, this review focuses on the efficacy of metformin as a monotherapy and as a combined therapy with other antidiabetic medications.

中文翻译：

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二甲双胍对非酒精性脂肪肝和糖尿病成人肝脂肪变性的影响：从细胞到患者水平的见解。

患有糖尿病的非酒精性脂肪性肝病 (NAFLD) 患者构成了一个肝脏相关并发症发生率高的患者亚组。目前，没有针对这些患者的具体药物推荐。二甲双胍是一种传统的胰岛素增敏剂，已广泛用于糖尿病患者。在 NAFLD 动物模型中，二甲双胍治疗已被证明可有效减轻肝脏脂肪生成，其中多种机制被认为是造成这种情况的原因。迄今为止，大多数研究都招募了接受二甲双胍治疗的糖尿病患者，并在整个研究过程中持续服用这种药物。尽管在临床前研究中存在关于二甲双胍对 NAFLD 的益处的证据，关于二甲双胍对成年 NAFLD 患者疗效的报告在肝脏生化和肝脏脂肪含量的变化方面存在一些差异。证据还表明二甲双胍在预防肝细胞癌肿瘤发生方面可能具有作用。进行此审查是为了全面总结可用的关于二甲双胍对治疗成人 NAFLD 糖尿病患者肝脂肪变性影响的体外、体内和临床研究。本综述包括一致的报告和有争议的发现，并提供了机械见解。此外，本综述重点关注二甲双胍作为单一疗法以及与其他抗糖尿病药物联合疗法的疗效。