Postacute ischemia vascular endothelial growth factor transfer by transferrin-targeted liposomes attenuates ischemic...

Our objective was to achieve the enhanced delivery of vascular endothelial growth factor (VEGF) to ischemically disordered brain through transferrin-coupled liposomes (Tf-PLs) via intravenous administration, and to observe the effect of Tf-VEGF-PLs on ischemic brain neuroprotection and angiogenesis. Cerebral VEGF overexpression was achieved with Tf-PLs by intravenous injection 48 hr after an acute stroke. β-Galactosidase expression was monitored; saline was injected as a control. The success of postischemic gene transduction was confirmed by β-galactosidase staining and by increased VEGF mRNA and protein in ischemic brain. Vascular density, neurological recovery, and ischemic area calculation were performed to evaluate the effect of Tf-VEGF-PLs. The positive expression of β-galactosidase indirectly indicated that VEGF was successfully delivered into brain by Tf-VEGF-PLs. VEGF mRNA in the Tf-VEGF-PL group 24 hr after injection was significantly higher than in the control group (p < 0.05). Western blot analysis showed that postischemic Tf-VEGF-PLs resulted in increased VEGF protein levels compared with VEGF-PLs and saline-administered rats (p < 0.05) 48 hr after administration. At 21 days after drug injection, we observed a significant decrease in infarct volume and better neurological function in the Tf-VEGF-PL-treated group, compared with the VEGF-PL group. FITC-dextran marking showed increased vascular density in the penumbra of Tf-VEGF-PL-treated hemispheres (245,873.9, number of microvessels per field) compared with that in VEGF-PL-treated hemispheres (139,801.3) or saline-treated hemispheres (102,175.5) (p < 0.05). The remainder of the cerebral blood flow after ischemia in the Tf-VEGF-PL group was significantly more than in the control groups (0.35 vs. 0.29, 0.21; p < 0.05). We conclude that the VEGF gene can be delivered noninvasively into the brain by Tf-VEGF-PLs. Postischemic treatment with Tf-VEGF-PLs effectively promoted neuroprotection and vascular regeneration in the chronic stage of cerebral infarction.