Fig. 1

Proposed mechanisms of action of MSCs transplantation. Paracrine effects of MSCs include the stimulation of angiogenesis, protection of other cells from apoptosis, recruitment of host MSCs or other progenitor cells and stimulation of their proliferation and differentiation [82, 83]. The immunomodulatory effects of MSC consist of inhibiting the proliferation and activity of neutrophils, NK cells, B cells, CD4⁺ cells and CD8⁺ T cells, preventing the maturation of monocytes into dendritic cells, suppressing plasma cell immunoglobulin production but stimulating proliferation of regulatory T cells [84]. In some physiological settings, MSCs are able to differentiate into multiple cell types and transfer vesicles containing mRNA, miRNA, proteins and perhaps mitochondria to the host cells [81, 84, 85]