Bovine mesenchymal stromal and induced pluripotent stem cell secretomes exhibit regenerative, but not antimicrobial, activity in vitro.

Abstract

The stem cell secretome, consisting of all factors secreted by stem cells, has been proposed as a useful therapy for repairing damaged tissues, as it can elicit the beneficial effects of stem cells without the risks of immune rejection and tumor formation associated with cellular therapy. In the current study, we assessed the therapeutic potential of the secretome from adult bovine mesenchymal stromal cells (MSCs). Our previous comparative transcriptomic study showed that human MSCs share more stem cell-related transcripts with MSCs from cows than with MSCs from mice, thus making bovine MSCs an appropriate model for translational stem cell studies. The bovine MSC secretome, collected as conditioned medium, increased fibroblast migration and promoted endothelial cell interactions, proxies for tissue regeneration, but only minimally inhibited the growth of bacteria in vitro. As antimicrobial activity is a desirable feature for treating tissues damaged by infection, we also explored the therapeutic potential of bovine induced pluripotent stem cells (iPSCs) based on the hypothesis that the secretome from pluripotent stem cells could have enhanced therapeutic effects over the secretome from multipotent stem cells. Similarly, the iPSC secretome increased fibroblast migration and promoted endothelial cell interactions in vitro but did not inhibit bacterial growth. Although the therapeutic potential of bovine stem cell secreted factors tested in this study is promising in terms of tissue regeneration, additional strategies must be employed to induce an antimicrobial effect.