Abstract <p>This opinion article examines the functional heterogeneity of cells composing adipose tissue (AT) and the potential for cross-species comparisons of single-cell transcriptomic analysis results using rodents as an example. Metabolic syndrome and obesity are closely related. In turn, obesity-associated AT dysfunction is accompanied by changes in cell composition of AT. The development of single-cell transcriptomic analysis methods in recent years, particularly snRNA-seq, and their popularization have provided a particularly powerful tool for studying the heterogeneity of AT cell composition. Animal models such as murine ones are widely used to study various aspects of AT biology; however, translating these findings to humans can be complicated by interspecies differences in the anatomy and cell composition of the tissue. This article summarizes some of the most important results of studying AT heterogeneity in humans and mice using such methods. To date, a number of functional subpopulations of both mature adipocytes and stromal-vascular fraction cells involved in their turnover are known. There is limited data in the literature on adipocyte subtypes and stromal-vascular fraction cells characterized by some comparability between humans and mice in terms of marker gene expression and obesity-induced changes. However, little data published to date on AT heterogeneity does not allow one to draw full conclusions on the interspecies comparability of AT cell subpopulation composition. This underscores the importance of a more detailed study of various aspects of AT cell heterogeneity.</p>