Contraindications of VEGF-based therapeutic angiogenesis: Effects on macrophage density and histology of normal and ischemic brains

Therapeutic angiogenesis by vascular endothelial growth factor (VEGF) is advocated as a promising treatment strategy for brain ischemic stroke. However, data in the literature demonstrating the benefit of therapeutic angiogenesis are contradictory. In this paper, we describe the effects of non-angiogenic and angiogenic doses of VEGF(165) on macrophage density and histology of normal and ischemic brains of adult rats. VEGF(165) was administered intra-arterially for 7 days following temporary occlusion of the middle cerebral artery. In contrast to ischemic brains treated with non-angiogenic doses of VEGF(165) which showed preserved neuropil and reduced numbers of macrophages, ischemic brains treated by an angiogenic dose showed phagocytized neuropil and high macrophage density. Though neither non-angiogenic nor angiogenic doses caused macrophage infiltration in normal brains, damage of the brain matrix occurred with the angiogenic dose. These results suggest an angiogenic dose of VEGF(165) injures the nervous tissue rather than promote recovery. Angiogenesis by VEGF monotherapy for ischemic stroke should be viewed with caution, or avoided. Since our data show intravascular administration of VEGF(165) does not cause macrophage inflammation, in contrast to reports in the literature whereby VEGF(165) was applied directly to the brain, our findings also indicate the relationships between VEGF, angiogenesis, and macrophage inflammation are governed by the route VEGF is administered to the brain. (c) 2006 Elsevier Inc. All rights reserved.