Background and Purpose: Reduced number and function of CD31+ circulating angiogenic
cells (CACs) may explain vascular complications associated with the chronic phase stroke.
The purpose of this study was to quantify CD31+ CAC paracrine function, total number and number
of various subtypes of CD31+ CACs in individuals with chronic stroke compared with controls.
Methods: Peripheral blood mononuclear cells were isolated from chronic stroke participants and
controls. CD31+ cells were quantified by flow cytometry, as was co-expression of CD31 in combination
with CD14, CD3, CD11b, or CD34. Immunomagnetically selected CD31+ cells were cultured,
and conditioned medium was used in a capillary-like network assay.
Results: Significantly lower levels of CD31+ CACs were found in stroke participants compared
with controls (-24%; P=0.04). Additionally, CD31+/CD14+, CD31+/CD11b+ and CD31+/CD3+
cells were significantly lower in the chronic stroke group compared with controls (-45%, P=0.02;
-47%, P=0.02 and -32%, P=0.03, respectively). There was no group effect on CD31+ CAC conditioned
media-mediated capillary-like network formation.
Conclusion: CD31+ CACs and subtypes may serve as potential therapeutic targets in chronic