Recent Advances in Stem Cell-Based Therapeutics for Stroke

Excerpt

Regenerative medicine has advanced the efficacy of exogenous and endogenous stem cells in restoring central nervous system disorders (CNS) in the aged and diseased brain [1‐3]. Stem cell therapy has been examined in numerous neurological disorders, with highly encouraging results suggesting its indication as a stroke treatment [4‐6]. In this regard, despite the availability of the thrombolytic agent tissue plasminogen activator (tPA) for stroke, its narrow therapeutic window and associated adverse events have not resolved the disease stigma as a major cause of mortality and morbidity around the world. Because stem cell therapy targets the subacute and chronic phases of stroke, thereby significantly extending the effective time of intervention, many patients are likely to benefit from this treatment. Several types of transplantable cells have been tested in the laboratory, with a few reaching clinical trials for cell therapy in stroke, including fetal cells, NT2N cells, CTX0E3, embryonic stem cells, neural stem/progenitor cells, umbilical cord blood, amnion, adipose, and induced pluripotent stem cells [7‐12]. Primarily, due to solid safety profile in other disease indications, preclinical studies and ongoing clinical trials have given special attention to bone marrow and its cellular derivatives [13, 14]. Direct intracerebral implantation and peripheral transplantation, such as intravenous, intra-arterial, and intranasal, have documented the functional benefits of bone marrow-derived stem cells [13, 15‐18]. Clinical trials have been initiated, and preliminary reports have demonstrated safety, although efficacy warrants additional investigations [14]. Here, we discuss the various sources and profiles of stem cells, with particular interest in the adult tissue-derived mesenchymal stem cells, their use in cell transplantation, translational challenges, and putative need for adjunctive therapies. Finally, we reflect on the current societal views that stem cell therapy in general has provoked in the public domain. Our goal is to assess the science behind regenerative medicine in an effort to advance the safe, effective, and mechanism-based application of cell therapy for stroke. …