Gender and age-related cell compositional differences in C57BL/6 murine adipose tissue stromal vascular fraction

Abstract

Adipose tissue is now recognized as a functional organ that contains cellular heterogeneity and diversity within anatomical depots. The stromal vascular fraction (SVF) of adipose contains endothelial progenitors, fibroblasts, lymphocytes, monocyte/macrophages, pericytes, pre-adipocytes, and stromal/stem cells, among others. In recent years, there has been a growing appreciation of the influence of age and gender in the field of stem cell biology. Yet few studies have evaluated the influence of biological age or sex on either SVF cell heterogeneity or immunophenotype. To address this issue, the current study has compared the flow cytometric characteristics between murine SVF of inguinal (iWAT), epidydimal (eWAT), and brown (BAT) adipose tissue of male and female, as well as young (6-8 week) and middle-aged (8-12 month) male C57BL/6 mice. Murine gender comparisons revealed male iWAT expressed higher percentages of leukocyte and CD34⁺ ASC-like sub-populations than female iWAT. Murine age comparisons revealed younger male iWAT, eWAT, and BAT SVF all contained a significantly higher percentage of pre-adipocytes, HSC-like cells, CD25^-, and FoxP3⁺ T-regulatory cells compared to SVF from middle-aged male mice. These findings highlight the potential contribution of biological variables on adipose-derived cell applications and experimental outcomes.

Keywords: C57BL/6 mice; Stromal vascular fraction (SVF) cells; adipose tissue; age analysis; cell composition; gender analysis; regenerative medicine.

Figure 1.

Gating strategies utilized for analyzing sub-populations within the stromal vascular fraction of mice. A. pre-adipocyte, ASC-like, and Endothelial-Like progenitor subpopulations within young and middle-aged male and female murine inguinal (iWAT) adipose depots. B. Detection of percent leukocyte subpopulations. C. Detection of percent NK and macrophage subpopulations.

Figure 2.

Percent subpopulations within 8–12 month female and 6–8 week and 8–12 month male C57Bl/6 murine inguinal (iWAT) adipose depots.The Venn diagrams display the percentage composition of the SVF cell profile in iWAT as a function of age and gender. Student's-test comparing inter-depot subpopulation expression. *p < 0.05, comparing iWAT to eWAT; ^#p < 0.05, comparing iWAT to BAT; & p <0.05, comparing eWAT to BAT.