Activation of TLR4 of Mesenchymal Stem Cells Enhances the Regenerative Properties of Their Secretomes.

Mesenchymal stem cells (MSC), like macrophages, can be polarized in vitro. In particular, activation of type 4 Toll-like receptor in MSC leads to the appearance of the so-called "proinflammatory" MSC phenotype (MSC1). We showed that secretome (conditioned media) of MSC1 can affect the wound healing processes: promote healing and modulate exudative inflammation and subsequent fibroplastic processes in the damaged area. These effects of secretomes of polarized MSC were superior to those of intact MSC.