OBJECTIVE Therapeutic neovascularization is a promising strategy for treating patients after an ischemic stroke; however, single-factor therapy has limitations. Stromal cell-derived factor 1 (SDF-1) and vascular endothelial growth factor (VEGF) proteins synergistically promote angiogenesis. In this study, the authors assessed the effect of combined gene therapy with VEGF165 and SDF-1 in a rat model of cerebral infarction. METHODS An adenoviral vector expressing VEGF165 and SDF-1 connected via an internal ribosome entry site was constructed (Ad- VEGF165-SDF-1). A rat model of middle cerebral artery occlusion (MCAO) was established; either Ad- VEGF165-SDF-1 or control adenovirus Ad- LacZ was stereotactically microinjected into the lateral ventricle of 80 rats 24 hours after MCAO. Coexpression and distribution of VEGF165 and SDF-1 were examined by reverse-transcription polymerase chain reaction, Western blotting, and immunofluorescence. The neurological severity score of each rat was measured on Days 3, 7, 14, 21, and 28 after MCAO. Angiogenesis and vascular remodeling were evaluated via bromodeoxyuridine and CD34 immunofluorescence labeling. Relative cerebral infarction volumes were determined by T2-weighted MRI and triphenyltetrazolium chloride staining. Cerebral blood flow, relative cerebral blood volume, and relative mean transmit time were assessed using perfusion-weighted MRI. RESULTS The Ad- VEGF165-SDF-1 vector mediated coexpression of VEGF165 and SDF-1 in multiple sites around the ischemic core, including the cortex, corpus striatum, and hippocampal granular layer. Coexpression of VEGF165 and SDF-1 improved neural function, reduced cerebral infarction volume, increased microvascular density and promoted angiogenesis in the ischemic penumbra, and improved cerebral blood flow and perfusion. CONCLUSIONS Combined VEGF165 and SDF-1 gene therapy represents a potential strategy for improving vascular remodeling and recovery of neural function after cerebral infarction.
Keywords: BrdU = bromodeoxyuridine; CBF = cerebral blood flow; CBV = cerebral blood volume; CXCR4 = chemokine receptor 4; Cy3 = cyanine 3; DAPI = 4′-6-diamidino-2-phenylindole; EPC = endothelial progenitor cell; FITC = fluorescein isothiocyanate; MCAO = middle cerebral artery occlusion; MTT = mean transmit time; MVD = microvascular density; PWI = perfusion-weighted imaging; RT-PCR = reverse-transcription polymerase chain reaction; SDF-1; SDF-1 = stromal cell-derived factor 1; T2WI = T2-weighted imaging; TTC = triphenyltetrazolium chloride; VEGF = vascular endothelial growth factor; VEGF165; VEGFR1 = VEGF receptor 1; angiogenesis; cerebral ischemia; gene therapy; mNSS = modified neurological severity score; r = relative; rat; therapeutic neovascularization.