Liposome-mediated transfer of the bcl-2 gene results in neuroprotection after in vivo transient focal cerebral ischemia in an animal model.
Acute cerebral ischemia causes hypoxic neuronal cell death by necrosis and apoptosis. Expression of anti-apoptotic transgenes in ischemic brain may provide a useful therapeutic strategy for alleviation of postischemic damage. The present study investigates liposome-mediated transfer of the human bcl-2 protein in a rat model of focal transient ischemia due to middle cerebral artery (MCA) occlusion. Two different types of plasmid vectors were used for bcl-2 expression: one driven by the constitutive cytomegalovirus promoter (pCMV) and another based on the hypoxia-inducible human vascular endothelial growth factor promoter (pHRE). Cationic liposome/plasmid DNA complexes (lipoplexes) were injected directly into the cerebrospinal fluid (CSF) of rats immediately after MCA occlusion. The brains of treated and control animals were analyzed 48 h later. Infarct volumes and numbers of apoptotic cells were quantified. Occlusion of the MCA resulted in ipsilateral cerebral infarcts in all study animals. Transfer of the bcl-2 gene resulted in high level widespread protein expression in the case of the pCMV-bcl2 plasmid, while animals treated with the pHRE-bcl2 vector showed lower expression levels of bcl2 which were in addition limited to the ischemic area. Treatment with pCMV-bcl2, but not with pHRE-bcl2, was able to significantly reduce the infarct volume, which was 109 +/- 8 mm(3) for pCMV-bcl2, 152 +/- 29 mm(3) for pHRE-bcl2, and 155 +/- 18 mm(3) for control animals. Animals transfected with either vector showed a significant reduction in numbers of apoptotic cells in the infarct and penumbra area compared with controls. There were no short-term neurological side-effects of the CSF injection of lipoplexes or of bcl-2 expression. In conclusion, the hypoxia-inducible bcl-2 expression mediated by intrathecal lipoplexes may represent a novel, biologically safe and lesion-selective therapeutic approach for neuroprotection after acute cerebral ischemia. DOI: 10.1038/sj/gt/3301676
Cao
Y-J
YJ
Molecular Neuro-oncology Laboratory, Department of Neurosurgery, Martin-Luther-University, Halle/S, Germany.
Shibata
T
T
Rainov
N G
NG
D000208:Acute Disease; D000818:Animals; D017209:Apoptosis; D002545:Brain Ischemia / Q000628:therapy*; D003587:Cytomegalovirus / Q000235:genetics; D016228:Endothelial Growth Factors / Q000235:genetics; D015870:Gene Expression; D019254:Genes, bcl-2; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors / Q000008:administration & dosage* / Q000235:genetics; D007278:Injections, Spinal; D008081:Liposomes; D008222:Lymphokines / Q000235:genetics; D008297:Male; D023421:Models, Animal; D011401:Promoter Regions, Genetic; D051381:Rats; D017208:Rats, Wistar; D014162:Transfection; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
D016228:Endothelial Growth Factors; D008081:Liposomes; D008222:Lymphokines; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors