Flavia A Cimini, Ilaria Barchetta, Maria-Gisella Cavallo, Laura Bertoccini, Marco G Baroni, Department of Experimental Medicine, Sapienza University of Rome, 00128 Rome, Italy.
World J Gastroenterol. 2017 May 21;23(19):3407-3417. doi: 10.3748/wjg.v23.i19.3407.
Non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide. Its pathogenesis is complex and not yet fully understood. Over the years many studies have proposed various pathophysiological hypotheses, among which the currently most widely accepted is the "multiple parallel hits" theory. According to this model, lipid accumulation in the hepatocytes and insulin resistance increase the vulnerability of the liver to many factors that act in a coordinated and cooperative manner to promote hepatic injury, inflammation and fibrosis. Among these factors, adipose tissue dysfunction and subsequent chronic low grade inflammation play a crucial role. Recent studies have shown that vitamin D exerts an immune-regulating action on adipose tissue, and the growing wealth of epidemiological data is demonstrating that hypovitaminosis D is associated with both obesity and NAFLD. Furthermore, given the strong association between these conditions, current findings suggest that vitamin D may be involved in the relationship between adipose tissue dysfunction and NAFLD. The purpose of this review is to provide an overview of recent advances in the pathogenesis of NAFLD in relation to adipose tissue dysfunction, and in the pathophysiology linking vitamin D deficiency with NAFLD and adiposity, together with an overview of the evidence available on the clinical utility of vitamin D supplementation in cases of NAFLD.
非酒精性脂肪性肝病（NAFLD）是全球最常见的慢性肝病。其发病机制复杂，尚未完全阐明。多年来，许多研究提出了各种病理生理假说，其中目前最广泛接受的是“多重平行打击”理论。根据该模型，肝细胞内脂质堆积和胰岛素抵抗增加了肝脏对许多协同作用的因素的易感性，这些因素共同促进肝损伤、炎症和纤维化。在这些因素中，脂肪组织功能障碍和随后的慢性低度炎症起着关键作用。最近的研究表明，维生素 D 对脂肪组织具有免疫调节作用，越来越多的流行病学数据表明，维生素 D 缺乏症与肥胖和 NAFLD 都有关。此外，鉴于这些情况之间存在很强的关联，目前的研究结果表明，维生素 D 可能参与了脂肪组织功能障碍与 NAFLD 之间的关系。本文综述了与脂肪组织功能障碍相关的 NAFLD 发病机制、维生素 D 缺乏与 NAFLD 和肥胖症之间的病理生理学联系的最新进展，以及维生素 D 补充治疗 NAFLD 的临床应用证据概述。
