Fig. 1

Age-associated decline in mesenchymal stromal cell (MSC)-mediated CD4⁺ T-cell suppression capacity. a MSCs from elderly donors (E-MSCs, ≥65 years, n = 23) are less efficient than those of non-elderly adults (A-MSCs, <65 years, n = 27) to suppress CD4⁺ T-cell proliferation at 1:8 MSC:CD4⁺ T cell ratio (**p = 0.003). b The suppressive effect of MSCs on CD4⁺ T cells depends on the MSC:CD4⁺ T-cell ratio (**p = 0.004). Twice the number of E-MSCs are required to affect CD4⁺ T-cell suppression to the same extent as A-MSCs (p > 0.9). c The effect of MSC donor age on the decline of CD4⁺ T-cell suppression is observed in patients with atherosclerosis (ATH; n = 18; p = 0.02, r = 0.4) and without ATH (non-ATH; n = 9; p = 0.02, r = 0.7)