Mesenchymal stem cells (MSCs) are under intensive investigation for use in

Mesenchymal stem cells (MSCs) are under intensive investigation for use in cell-based therapies because their differentiation abilities immunomodulatory effects and homing properties offer potential for significantly augmenting regenerative capacity of many tissues. stress-mediated MSC depletion occurs due to inflammatory processes associated with chemotherapy radiotherapy and expression of pro-apoptotic factors and the microenvironment of damaged tissue in patients receiving MSC therapy is typically therapeutic not favorable to their survival. For this reason any strategies that enhance the viability and proliferative capacity of MSCs associated with their therapeutic use are of great value. Here recent strategies used by various researchers to improve MSC allograft function are reviewed with particular focus on in vitro conditioning of MSCs in preparation for clinical application. Preconditioning genetic manipulation and optimization of MSC culture conditions are some examples of the methodologies described in the present article along with novel strategies such as treatment of MSCs with secretome and MSC-derived microvesicles. This topic material Iloprost is likely to find value as a guide for both Iloprost research and clinical use of Iloprost MSC allografts and for improvement of the value that use of these cells brings to health care. Keywords: Mesenchymal stem cell Preconditioning Scaffold Conditioned medium Microenvironment Bioreactor Introduction Self-renewal differentiation and regeneration capacities are Iloprost the main characteristics of stem cells making them ideal tools for treatment of some congenital or acquired diseases or for their application in gene therapy drug delivery and Iloprost regenerative medicine (Biffi et al. 2013; Garbern and Lee 2013; Greco and Rameshwar 2012; Law and Chaudhuri 2013; Murphy et al. 2013; Przybyla et al. 2013; Saunders et al. 2013). Hence recently embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSC) have gained intensive research attention in cell therapy experiments (Cai et al. 2013a; Ito et al. 2013; Kuhn et al. 2013; Liu et al. 2013; Shtrichman et al. 2013; Toh et al. 2011). However despite the differentiation capacity of the ESCs and iPSCs potential tumorigenesis ethical concerns and graft versus host disease (GVHD) are the major challenges in development and clinical application of these cells (Brind’Amour 2012; Herberts et al. 2011; Knoepfler 2009; Lodi et al. 2011; Malard and Mohty 2014; Mertes and Pennings 2009; Takahashi et al. 2007). Due to ERCC6 these limitations mesenchymal stem cells (MSCs) are now much more interested for application in cell-based therapy (Law and Chaudhuri 2013; Murphy et al. 2013; Wei et al. 2013). MSCs are plastic-adherent-multipotent stem cells that are able to differentiate to at least osteo adipo and chondrocytes and also several other cell types (Dominici et al. 2006; Li et al. 2013b). They are easily isolated from bone marrow adipose tissue peripheral blood dermis umbilical cord (UC) umbilical cord blood (UCB) amnion fluid and placenta somehow without any invasive procedure (Choudhery et al. 2013; Koliakos et al. 2011; Lee et al. 2010; Lindenmair et al. 2012; Mennan et al. 2013; Ribeiro et al. 2013). Despite some differences between MSCs originated from various sources they share the main characteristics mentioned above (Al-Nbaheen et al. 2013; Choudhery et al. 2013; Jin et al. 2013). MSCs have paracrine effects with immunomodulatory properties because of their ability to secrete several cytokines and chemokines (Arno et al. 2014; Linero and Chaparro 2014; Song et al. 2013). However application of MSCs in cell therapy has been hindered due to various limitations such as their low proliferation rate (Han et al. 2014; Liu et al. 2009; Yoon et al. 2011) restricted life span and gradual loss of stemness during ex vivo expansion (Fossett and Khan 2012; Liu et al. 2009). Various stress conditions including oxidative stresses imposed through isolation and in vitro expansion of MSCs could induce apoptosis (Wei et al. 2010; Han et al. 2013) resulting in more than 99?% cell death during the first few days after transplantation (Lee et al. 2009b; Toma Iloprost et al. 2002; Zhang et al. 2001). Moreover the toxic environment caused by inflammation.