The Differential Roles of T Cells in Non-alcoholic Fatty Liver Disease and Obesity

Non-alcoholic fatty liver disease (NAFLD) constitutes a spectrum of disease states characterized by hepatic steatosis and is closely associated to obesity and the metabolic syndrome. In non-alcoholic steatohepatitis (NASH), additionally, inflammatory changes and hepatocellular damage are present, representing a more severe condition, for which the treatment is an unmet medical need. Pathophysiologically, the immune system is one of the main drivers of NAFLD progression and other obesity-related comorbidities, and both the innate and adaptive immune system are involved. T cells form the cellular component of the adaptive immune system and consist of multiple differentially active subsets, i.e., T helper (Th) cells, regulatory T (Treg) cells, and cytotoxic T (Tc) cells, as well as several innate T-cell subsets. This review focuses on the role of these T-cell subsets in the pathogenesis of NAFLD, as well as the association with obesity and type 2 diabetes mellitus, reviewing the available evidence from both animal and human studies. Briefly, Th1, Th2, Th17, and Th22 cells seem to have an attenuating effect on adiposity. Th2, Th22, and Treg cells seem to decrease insulin resistance, whereas Th1, Th17, and Tc cells have an aggravating effect. Concerning NAFLD, both Th22 and Treg cells appear to have an overall tempering effect, whereas Th17 and Tc cells seem to induce more liver damage and fibrosis progression. The evidence regarding the role of the innate T-cell subsets is more controversial and warrants further exploration

Pharmacological approaches in the treatment and maintenance of weight loss

Obesity is a growing global health concern, associated with a number of important comorbid conditions. It increases the risk of diabetes and contributes to development of cardiovascular disease. While the benefits of weight loss are well established, weight reduction remains a difficult-to-reach goal in overweight and obese individuals due to several metabolic and psychological factors. For many patients, lifestyle intervention is insufficient to achieve long-term weight loss, and additional options, such as pharmacotherapy, need to be considered. Besides the challenging enterprise of weight reduction, weight maintenance remains an even more crucial and outcome-determining aspect of weight management. This article focuses on the potential of currently available pharmacological strategies to support weight loss and maintenance goals in individuals at risk. Two pharmacotherapy types are considered: those developed primarily to induce weight loss and those developed primarily for blood glucose control that have a favorable effect on body weight. Finally, the potential of very low- and low-calorie diets combined with pharmacotherapy and pharmacological combination therapies are discussed, as well as emerging approaches in development.</jats:p