Synergistic Effects of Transplanted Endothelial Progenitor Cells and RWJ 67657 in Diabetic Ischemic Stroke Models

Background and purpose: An immature vascular phenotype in diabetes mellitus may cause more severe vascular damage and poorer functional outcomes after stroke, and it would be feasible to repair damaged functional vessels using endothelial progenitor cell (EPC) transplantation. However, high glucose induces p38 mitogen-activated protein kinase activation, which can accelerate the senescence and Apoptosis of EPCs. The aim of this study was to investigate the combined effects of EPC transplantation and p38 mitogen-activated protein kinase inhibitor administration on diabetic stroke outcomes.

Methods: Bone marrow-derived EPCs were injected intra-arterially into db/db mice after ischemic stroke induction. RWJ 67657 (RWJ), a p38 mitogen-activated protein kinase inhibitor, was administered orally for 7 consecutive days, with the first dose given 30 minutes before stroke induction. Functional outcome was determined at days 0, 1, 7, 14, and 21. Angiogenesis, neurogenesis, infarct volume, and Western blotting assays were performed on day 7, and white matter remodeling was determined on day 14.

Results: Neither EPC transplantation nor RWJ administration alone significantly improved diabetic stroke outcome although RWJ displayed a potent anti-inflammatory effect. By both improving the functioning of EPCs and reducing inflammation, EPC transplantation plus RWJ administration in vivo synergistically promoted angiogenesis and neurogenesis after diabetic stroke. In addition, the white matter remodeling, behavioral scores, and expressions of vascular endothelial growth factor and brain-derived neurotrophic factor were significantly increased in diabetic mice treated with both EPCs and RWJ.

Conclusions: The combination of EPC transplantation and RWJ administration accelerated recovery from diabetic stroke, which might have been caused by increased levels of proangiogenic and Neurotrophic Factors.