Scaffolds for Intracerebral Grafting of Neural Progenitor Cells After Cerebral Infarction: A Systematic Review

CONTEXT Intracerebral grafting of neural progenitor cells is a promising potential treatment to improve recovery after stroke, but the structural disruption and cavitation of brain tissue that occurs creates an unfavorable environment for graft cell survival. To overcome this obstacle, scaffold materials have been used as extracellular matrix to provide structural support for the transplanted cells. Many materials could potentially be used as scaffolds for this application. EVIDENCE ACQUISITION We performed a systematic review to determine the available evidence supporting specific scaffolds for neural progenitor cell grafting after stroke. Articles were identified with a MeSH search on PubMed. Relevant references and "related articles" of selected manuscripts were also reviewed. Full original articles published prior to May 2013 presenting unique experimental data describing intracerebral grafting of neural progenitor cells in a scaffold after cerebral infarction were included in our study. All selected articles were reviewed thoroughly by the authors for relevant data. RESULTS We found reports of use of scaffolds composed of polyglycolic acid, poly [lactic-co-glycolic acid] particles (with and without VEGF), hyaluronan-heparin-collagen hydrogel, Matrigel, collagen and extracellular matrix derived from porcine brain and urinary bladder. While multiple beneficial effects were reported, the optimal scaffold is unclear as we found no direct comparisons. CONCLUSIONS We conclude that multiple scaffolds appear promising for neural progenitor cell grafting after stroke, but further research is needed to optimize this neurorestorative approach. Thus, we hope to provide a basic understanding of the state of scaffolds for neural progenitor cell grafting after stroke and to encourage further research. Based on the methods of the discussed studies, we propose a standardized set of outcomes that would best be used to evaluate and compare the effectiveness of a given scaffold.