Obesity is a major health problem in highly industrialized countries. High-fat diet (HFD) is one of the most common causes of obesity and obesity-related disorders. There are considerable differences between fat depots and the corresponding risks of metabolic disorders. We investigated the various effects of an excess of fatty acids (palmitic 16:0, stearic 18:0, and oleic acids 18:1n-9) on adipogenesis of subcutaneous- and visceral-derived mesenchymal stem cells (MSCs) and phenotypes of mature adipocytes. MSCs of white adipose tissue were acquired from adipose tissue biopsies obtained from subcutaneous and visceral fat depots from patients undergoing abdominal surgery. The MSCs were extracted and differentiated in vitro with the addition of fatty acids. Oleic acid stimulated adipogenesis, resulting in higher lipid content and larger adipocytes. Furthermore, oleic acid stimulated adipogenesis by increasing the expression of CCAAT enhancer binding protein β (CEBPB) and peroxisome proliferator activated receptor γ (PPARG). All of the examined fatty acids attenuated the insulin-signaling pathway and radically reduced glucose uptake following insulin stimulation. Visceral adipose tissue was shown to be more prone to generate inflammatory stages. The subcutaneous adipose tissue secreted a greater quantity of adipokines. To summarize, oleic acid showed the strongest effect on adipogenesis. Furthermore, all of the examined fatty acids attenuated insulin signaling and secretion of cytokines and adipokines.
Keywords: SAT; VAT; adipogenesis; insulin signaling; oleic acid; palmitic acid.