1 Department of Health, Kinesiology, and Applied Physiology, Concordia University, Montreal, Quebec, Canada.
2 Metabolism, Obesity, and Nutrition Lab, School of Health, Concordia University, Montreal, Quebec, Canada.
3 Centre de recherche - Axe maladies chroniques, Centre intégré universitaire de santé et de services sociaux du Nord-de-l'Ile-de-Montréal, Hôpital du Sacré-Coeur de Montréal, Montréal, Québec, Canada.

The excessive accumulation of adipose tissue in obesity appears to result in adipose tissue dysfunction perpetuating the onset of obesity-related diseases, including type 2 diabetes (T2DM). In humans, adipose tissue is stored in several depots including subcutaneous and visceral. These depots contribute to the pathology of obesity differently owing to differences in the tissue microenvironment, a main one being preadipocyte function. In examining adipocyte and preadipocyte characteristics, many have used the 3T3-L1 murine cell lines. Though these cell lines provide valuable mechanistic data, the results remain to be translated to humans. Experiments using primary human preadipocytes has shown that obesity and T2DM impact preadipocyte phenotypes. The objective of this review is to describe the differences in regional characteristics of primary preadipocytes collected from humans with obesity and to discuss how these characteristics might be affected in type 2 diabetes mellitus. In doing so, we will show that the characteristics of regional primary preadipocytes in humans are differentially affected by obesity and the development of T2DM.