TNF and chronic obstructive pulmonary disease: Consistent with these reports, in the experimental models of COPD, MSCs could also modulate release of inflammation-associated factors, that is, inhibiting pro-inflammatory cytokines or mediators such as IL-1β, TNF-α, IL-6, and PGE2 [29, 30, 33, 37], stimulating anti-inflammatory cytokine IL-10 [29], and up-regulating synthesis of growth factors associated with tissue repair such as VEGF, HGF, EGF and TGF-β1 [10, 23, 26, 28, 33, 37].