Stroke is a leading cause of adult disability. Stem/progenitor cell
transplantation improves recovery after
stroke in rodent models. These studies have 2 main limitations to clinical translation. First, most of the cells in stem/progenitor transplants die after brain
transplantation. Second, intraparenchymal approaches target transplants to normal brain adjacent to the
stroke, which is the site of the most extensive natural recovery in humans.
Transplantation may damage this tissue. The
stroke cavity provides an ideal target for
transplantation because it is a compartmentalized region of
necrosis, can accept a high volume transplant without tissue damage, and lies directly adjacent to the most
plastic brain area in
stroke. However, direct
transplantation into the
stroke cavity has caused massive death in the transplant. To overcome these limitations, the authors tested stem/progenitor transplants within a specific
biopolymer hydrogel matrix to create a favorable environment for
transplantation into the
infarct cavity after
stroke, and they tested this in comparison to stem cell injection without
hydrogel support. A
biopolymer hydrogel composed of cross-linked
hyaluronan and
heparin sulfate significantly promoted the survival of 2 different neural progenitor cell lines in vitro in conditions of stress and in vivo into the
infarct cavity. Quantitative analysis of the transplant and surrounding tissue indicates diminished inflammatory infiltration of the graft with the
hydrogel transplant. This result indicates that altering the local environment in
stem cell transplantation enhances survival and diminishes cell stress.
Stem cell transplantation into the
infarct cavity within a pro-survival
hydrogel matrix may provide a translational
therapy for
stroke recovery.