Senescent cells in human adipose tissue: A cross-sectional study

Objective: Adipose tissue (AT) senescence is associated with AT dysfunction in rodents, but little is known about human AT senescence. The study goal was to define the distribution of senescent cells in two subcutaneous depots and understand relationships with adiposity and inflammation. Methods: Sixty-three volunteers (48 females) underwent abdominal and femoral subcutaneous fat biopsies. Fat cell size, senescent cells using senescence-associated β-galactosidase staining per 100 nucleated cells (percentage), and mRNA expression of four cytokines were measured. Results: There was a larger proportion of senescent cells in femoral than abdominal subcutaneous AT (mean difference 1.6% [95% CI: 0.98%-2.3%], p < 0.001), and the percentage of femoral AT senescent cells was greater in women than men (median 3.9% vs. 2.1%, p < 0.01). There was a positive correlation between senescence and fat cell size in abdominal (r_s = 0.44, p < 0.001) and femoral (r_s = 0.35, p = 0.007) AT depots. Abdominal AT tumor necrosis factor alpha (r_s = 0.49, p < 0.01) and interleukin-1β (r_s = 0.44, p = 0.01) expression was positively correlated with abdominal, but not femoral, AT senescence. Conclusions: In human subcutaneous AT, there are more senescent cells in femoral than abdominal depots; abdominal AT senescent cells are more associated with inflammatory signals than femoral AT senescent cells.