Systemic administration of mesenchymal stem cells can trigger distal (endocrine) or local (paracrine) effects that include cell-mediated actions. 1) Promotion of angiogenesis: vascular endothelial growth factor (VEGF), insulin like growth factor 1 (IGF-1), monocyte chemoatractant protein 1 (MCP-1), basic fibroblast growth factor (bFGF) and interleukin 6 (IL-6). 2) Stem cell growth and differentiation: stem cell factor (SCF), leukemia-inhibitory factor (LIF), macrophage colony-stimulating factor (M-CSF), stromal derived factor 1 (SDF-1), angiopoietin 1 and activin A. 3) Inhibition of fibrosis: hepatocyte growth factor (HGF), bFGF, adrenomedullin (ADM). 4) Inhibition of apoptosis: VEGF, HGF, IGF-1, transforming growth factor (TGF)-β, bFGF, granulocyte macrophage colony-stimulating factor (GM-CSF), activin A and thrombospondin-1. Immune mediated effects include the following (5 to 8). 5) Suppression of T and B cells: human leukocyte antigen G5 (HLA-G5), HGF, inducible nitric oxide synthase (iNOS), indoleamine-2,3-dioxygenase (IDO), prostaglandin E2 (PGE-2), bFGF and TGF-β. 6) Induction of regulatory T cell (Treg) differentiation and expansion by TGF-β expression. 7) Inhibition of natural killer (NK) cells by secretion of IDO, PGE-2 and TGF-β. 8) Inhibition of dendritic cell (DC) maturation by secretion of PGE-2. iDC, immature dendritc cells; mDC, mature dendritic cells.