Degree Granting Department
Pathology and Laboratory Medicine
Alison E. Willing.
MCAO, neuroprotection, neuroinflammation, spleen, stem cells
Infusion of the "mononuclear fraction" of human cord blood cells (HUCBC), which is composed of immature blood cells and hematopoietic progenitors, is known to reduce neurobehavioral deficits in rats subject to middle cerebral artery occlusion (MCAO). When MCAO rats are infused with 10â¶ cells 24 hours after the induction of the stroke, their motor function improves. To extend these findings, we first examined the behavioral recovery of MCAO rats in the presence of increasing doses of HUCBC. The recovery in behavioral performance seen with measurements of spontaneous activity and motor deficits, depended on the amount of cells delivered, with 10â¶ HUCBC being the threshold for significant behavioral recovery. Measurements of the ischemic volume revealed an inverse relationship between HUCBC dose and damage volume, which reached significance at the higher HUCBC doses (10â· and 3-5x10â· cells).
Moreover, investigation of the distribution of the intravenously injected cells showed that HUCBC were localized to the injured brain hemisphere and the spleen. Given these findings, we hypothesized that there may be a role of HUCBC in the modulation of the peripheral or brain-localized immune response that is normally evoked after stroke. Results on the effect of HUCBC infusion on splenocytes indicated that HUCBC treatment prevented the alterations in splenocyte type (CD8+ depletion) and function (T-cell suppression) induced by stroke. In particular, examination of cytokine production from splenocyte cultures of HUCBC-treated MCAO rats revealed increased production of IL-10 and decreased production of IFNgamma relative to MCAO rats. Microglia (immunostained with a CD11b antibody) and B cells (identified with the B220 cell marker) that were increased after MCAO were dramatically decreased after HUCBC treatment.
Proinflammatory cytokines such as TNF-alpha, IL-1beta and IL-2 were upregulated after MCAO surgery and their expression was abrogated after HUCBC infusion. All these findings indicate that the action of HUCBC may be specifically related to the modulation of the stroke-induced inflammatory response, providing a possible mechanism by which cord blood cells have been repeatedly reported to promote functional recovery from ischemic injury.
Scholar Commons Citation
Vendrame, Martina, "Cord blood cell therapy for ischemic stroke" (2004). Graduate Theses and Dissertations.