Stem Cell Activity Towards Tissue Regeneration - 1427 Words

Go to: Introduction DESPITE embryonic stem cell potential differentiating into many cell types in the blastocyst stage, most adult stem cells had known inherent limited potential for postnatal tissue and organ regeneration. Among the sources of phenotypically characterized adult stem/progenitor cells,1–3 the hematopoietic system has traditionally been known as an organized, hierarchical system spearheaded by multipotent and self-renewing stem cells at the top, followed by lineage-committed progenitor cells in the middle, and finally, lineage-restricted precursor cells at the bottom, which give rise to terminally differentiated cells.4 However, another stem cell population, adult human circulating/peripheral blood (PB) CD34+ cells, has been†¦show more content†¦Several studies using an immunodeficient rat model of acute myocardial infarction have demonstrated effective transplantation of either human CD34+cells or ex vivo-expanded EPCs into the site of myocardial neovascularization. Follo wing transplantation, these cells could differentiate into mature endothelial cells, augment capillary density, inhibit myocardial fibrosis and apoptosis, and finally preserve left ventricular function.10,12,13,17 Based on these promising results, clinical trials using PB CD34+ cells have been performed with initial good clinical outcomes.18–20 TABLE 1. THERAPEUTIC APPLICATION OF CD34+ CELLS/EPCS FOR VARIOUS DISORDERS In various areas of regenerative medicine, a lot of investigations on the promotion of tissue neovascularization with EPCs have led to widen applications for these cells. These areas include brain tissue regeneration, for which EPCs have been successfully applied. Human cord blood-derived CD34+ cells were systemically transplanted in immunocompromised mice within 48 h of sustaining a stroke, inducing neovascularization at the site of the ischemic zone and providing a favorable environment for neuronal regeneration.21 PB CD34+ cell transplantation has been also reported to promote tissue healing via revascularization include full-thickness skin wounds of diabetic mice, peripheral nerve injuries, and spinal cord