Safety of mesenchymal stem cells therapy
More than 10 years mesenchymal stem cells(MSCs) have been used in treatment of different diseases, most importantly in tissue degeneration, irradiation damage, hematopoetic and posttransplant diseases as well as in refractory chronic inflammatory, fibrosing and fistulizing diseases. They have unique properties such as immunomodulatory, proangiogenetic and antifibrotic, therefore, MSCs inhibit inflammation, fibrosis and promote regeneration of tissue damage. These cells can be isolated from bone marrow, adipose tissue, cord blood and potentially from muscle, gingiva and fetal liver. In addition they are non-immunogenic and can be transplanted without conditioning and without immunosuppressive prophylaxis. Therefore, MSCs represent an attractive clinical approach for the treatment of chronic inflammatory, fibrosing and fistulizing diseases[1].
It is considered that the microenvironment of damaged tissues produces factors that attract stem cells to the site of injury and enhances their differentiation into desired cells. Thus, MSCs promote tissue regeneration by differentiating into the injured cells[2]. Moreover, in the presence of MSCs, immature or partially immature antigen presenting cells are produced which turn off T cells leading to down-regulation of activated immune cell reactivity. Due to their immunomodulatory potential, MSCs reduce tissue damage[3].
There are data which were obtained on animal models that MSCs due to their immunosuppression ability can promote tumor growth. It is crucial to specify that it was demonstrated on animals with preexisting malignancies[4]. Moreover, it has been showed that MSCs don’t undergo malignant transformation in long-term culture[5]. Also, oncogenic transformation of MSCs and induction of malignancy by them wasn’t seen in vitro or in vivo. Tarte K. et al. in 2010 demonstrated that MSCs with or without chromosomal alterations showed growth arrest and entered senescence without evidence of transformation[6].
Credits: Swiss Medica