Can mesenchymal stem cells improve spermatogonial stem cell transplantation efficiency?

Improved treatments have led to an increased survival rate in cancer patients. However, in pre-pubertal boys, these gonadotoxic treatments can result in the depletion of the spermatogonial stem cell (SSC) pool causing lifelong infertility. SSC transplantation has been proposed as a promising technique to preserve the fertility of these patients. In mice, this technique has resulted in live-born offspring, but the efficiency of colonization remained low. This could be because of a deficient microenvironment, leading to apoptosis of the transplanted SSCs. Interestingly, mesenchymal stem cells (MSCs), being multipotent and easy to isolate and multiply in vitro, are nowadays successfully and widely used in regenerative medicine. Here, we shortly review the current understanding of MSC and SSC biology, and we hypothesize that a combined MSC-SSC transplantation might improve the efficiency of SSC colonization and differentiation as paracrine factors from MSCs may contribute to the SSC niche.