Non-alcoholic fatty liver disease and type 2 diabetes mellitus: the problem of conjunction and phasing

The widespread prevalence of non-alcoholic fatty liver disease (NAFLD) and type 2 diabetes mellitus (T2DM), as well as their combination, determines the need for a targeted analysis of this pathology in order to optimize approaches to the diagnosis and treatment of patients with NAFLD and T2DM. As components of the metabolic syndrome, these two diseases have largely similar mechanisms of development and progression, simultaneously increasing the risk of adverse outcomes in comorbid patients. Despite the common pathophysiological mechanisms, the question of the development of NAFLD and T2DM remains significant. Upon conducting literature analysis, two main theories have been identified: alimentary and metabolic. According to the alimentary theory, the primary link in the pathogenesis is obesity and the associated excessive accumulation of free fatty acids and triglycerides in the liver, which subsequently leads to insulin resistance and the development of T2DM. In contrast, the metabolic theory considers diabetes-related insulin resistance as the first hit, which, regardless of obesity, creates preconditions for liver damage. In addition, the review focuses on the consideration of the new concept of Metabolic associated fatty liver disease (MAFLD) as a hepatic manifestation of the metabolic syndrome and considers the clinical phenotypes identified within this pathology. In conclusion, pathogenically based treatment goals in patients with NAFLD and T2DM are overcoming insulin resistance, correcting atherogenic dyslipidemia, and restoring the structures and functions of liver cells.