228. A Novel Therapeutic Strategy To Treat Brain Ischemia: Over-Expression of Hepatocyte Growth Factor Gene Reduced Ischemic Injury without Cerebral Edema in Rat Model
Authors: Munehisa Shimamura, Naoyuki Sato, Toshio Ogihara, Yasufumi Kaneda, Ryuichi Morishita
Journal: Molecular Therapy (2004)

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Cerebral occlusive disease caused by atherosclerosis of the cerebral arteries or Moyamoya disease often causes global ischemia of the brain. Although such a condition leads to not only cerebral ischemic events, but also neuropathological changes including dementia, an effective treatment to improve brain ischemic injury has not yet been established. It is known that ischemic stroke induces active angiogenesis, particularly in the ischemic penumbra, which correlates with longer survival in humans. However, the natural course of angiogenesis is not sufficient to compensate for the hypoperfusion state. Recently, a novel therapeutic strategy using genes of angiogenic growth factors and neurotrophic factors has been proposed for the treatment of cerebrovascular disease. In the present study, we examined the effects of hepatocyte growth factor (HGF) in a rat middle cerebral artery occlusion model.

First, human HGF gene was transferred into the brain via the cisterna magna using HVJ-envelope vector. The concentration of human HGF and rat HGF in CSF were measured by ELISA at 5 and 12 days after gene transfer. On day 5, as expected, human HGF could be detected in the CSF of rats transfected with human HGF vector, while human HGF protein could not be detected in control rats. The increase in human HGF protein in the CSF continued up to 12 days after transfection. Consistently, up-regulation of c-met was observed in the cerebral cortex as well as the brain stem and cerebellum. Next, the middle cerebral artery was occluded 5 days after HGF gene transfer. Over-expression of the HGF gene resulted in a significant decrease in the infarcted brain area after 24 hours of ischemia, whereas control group showed large infarction (48 ± 3.0 % vs 72 ± 5.9 %, P<0.05). Consistently, the neurological deficit was attenuated in rats transfected with HGF gene (score = 1.0 ± 0.2 in HGF group and 1.4 ± 0.2 in control group, P<0.01). Numerous TUNEL-positive cells were observed in rats transfected with control vector, while a significant decrease in TUNEL positive cells was detected in rats transfected with HGF gene. Stimulation of angiogenesis without destruction of the blood-brain barrier was also detected in rats transfected with the HGF gene as compared to control group (the vessel area = 152.7 ± 6.9 mm2/mm2 vs 95.8 ± 7.7 mm2/mm2, p<0.01). Of importance, no exacerbation of cerebral edema was observed in rats transfected with the HGF gene (water content = 75.9 ± 0.01% in HGF group vs 77.9 ± 0.01% in control group, p<0.01).

Overall, HGF gene transfer using HVJ-envelope vector reduced ischemic injury without exacerbation of cerebral edema or BBB leakage. Although further studies on the safety are necessary, gene therapy using HGF may provide new therapeutic options for the treatment of cerebral ischemia. Continuous development of systems involving vectors, promoters or alternative routes of administration may help to achieve human gene therapy for cerebrovascular disease in the future.