Figure 1.

Current failures in cell therapy. (A) The patient’s age and mechanical and pathological conditions are among the factors that affect the therapeutic potential of cell therapy. In particular, transplanted cell survival may be affected by (i) mechanical stress during the transplantation procedure; (ii) a harsh microenvironment due to the activation of inflammation-related factors; (iii) oxygen and nutrient starvation due to poorly vascularized environments at the site of implantation; and (iv) a lack of optimization of the delivery protocols. (B) The benefits of cell transplantation could be improved by donor cell preconditioning or modifying transplanted cells prior to implantation to support or enhance their resistance to hypoxic stress. (C) The tissue engineering approach could enhance the survival of transplanted cells through the use of suitable biomaterials as carriers, such as a biologic-derived ECM scaffold. O₂ = oxygen; Bcl-2 = B-cell lymphoma 2; EPO = erythropoietin.