Human Hair Follicle-Derived Mesenchymal Stromal Cells from the Lower Dermal Sheath as a Competitive Alternative for Immunomodulation

Mesenchymal stromal cells (MSCs) have unique immunomodulatory capacities. We investigated hair follicle-derived MSCs (HF-MSCs) from the dermal sheath, which are advantageous as an alternative source because of their relatively painless and minimally risky extraction procedure. These cells expressed neural markers upon isolation and maintained stemness for a minimum of 10 passages. Furthermore, HF-MSCs showed responsiveness to pro-inflammatory environments by expressing type-II major histocompatibility complex antigens (MHC)-II to a lesser extent than adipose tissue-derived MSCs (AT-MSCs). HF-MSCs effectively inhibited the proliferation of peripheral blood mononuclear cells equivalently to AT-MSCs. Additionally, HF-MSCs promoted the induction of CD4+CD25+FOXP3+ regulatory T cells to the same extent as AT-MSCs. Finally, HF-MSCs, more so than AT-MSCs, skewed M0 and M1 macrophages towards M2 phenotypes, with upregulation of typical M2 markers CD163 and CD206 and downregulation of M1 markers such as CD64, CD86, and MHC-II. Thus, we conclude that HF-MSCs are a promising source for immunomodulation.This work was supported by the projects SAF2017-82292-R (MINECO), MCIU-AEI/ FEDER, UE, ICTS “NANBIOSIS” Drug Formulation Unit (U10) and the Eusko Jaurlaritza (Grupos Consolidados, No ref: IT907-16)

The Use of Mesenchymal Stromal Cells and Tissue-Engineered Blood Vessels for Seamless Implant Integration

223 p.In recent years, organ transplantation technology has made significant improvements regarding long-term survival, substantially decreasing the risk of graft rejection. However, with each passing year,the gap between available donors and the number of patients needing an organ transplant is steadilyincreasing. Consequently, there is a growing demand to create engineered tissues to minimize the needfor organ transplantation. However, the rejection of engineered tissue implants has become a criticalchallenge today. Primarily, rejection occurs due to the crosstalk between immune cells, such asmacrophages, and the engineered tissue structure. Therefore, it is important to be able to influence theimmune cell milieu of the implantation site to achieve graft integration. With this perspective in mind,this doctoral thesis aimed to provide two different strategies: The first one is the use of human hairfollicle derived mesenchymal stromal cells (HF-MSCs) for immunomodulation. For that, we isolate andcharacterize MSCs from human hair follicles and then, we analyzed the immunomodulatory capacity ofthe cells by means of the inhibition of peripheral mononuclear cells (PBMCs), inducing T regulatoryphenotype and skewing macrophages towards a tissue remodeling phenotype (aka M2). The secondstrategy relied on the application of tissue-engineered blood vessels to interact with different macrophagephenotypes and thus promoting a tissue remodeling response around the implant. The effects of bloodvessels on undifferentiated (M0), pro-inflammatory (M1) and regenerative (M2 and M1M2) macrophagephenotypical change were assessed by single cell analysis, specifically using dimensionality reductionand clustering algorithms for a thorough characterization of resulted macrophage phenotype. Therefore,we could conclude that both strategies could have an important developmental impact towards theimplementation of immunomodulatory techniques and could have important consequences for tissue engineering.NanoBioCe