Background: Reconstituted high-density lipoprotein (rHDL) is prepared from apolipoprotein A-I, isolated from human plasma, and soybean-derived phosphatidylcholine and exhibits biochemical and functional characteristics similar to endogenous nascent high-density lipoprotein (HDL). This study tested the hypothesis that pretreatment with rHDL may reduce neuronal damage in 2 experimental rat models of stroke. Methods: In the first model, an excitotoxic lesion was induced by unilateral injection of N-methyl-D-aspartate (NMDA) in the right striatum (excitotoxic lesion model). In the second model, temporary occlusion of the middle cerebral artery (MCA) was attained by inserting a nylon thread through the carotid artery and blood flow was restored 30 min later (MCAo model). In both models, either rHDL (120 mg/kg) or saline (control) were infused over 4 h, starting 2 h before the injection of NMDA or the induction of ischemia, respectively. 24 h after the interventions, the rats were sacrificed and the brains removed for histochemical preparation. The necrotic area was delimited using an image analysis system. In addition, the levels of reactive oxygen species (ROS) in human endothelial (ECV 304) and neuroblastoma (SK-N-BE) cell lines were measured fluorometrically as 2′,7′-dichlorofluorescein fluorescence in the presence and absence of rHDL and under basal and stress-induced conditions. Results: In the excitotoxic lesion and MCAo models, pretreatment with rHDL significantly reduced the brain necrotic area by 61 and 76%, respectively (p < 0.01). Overnight incubation of ECV 304 and SK-N-BE cells with 0.5 mg/ml rHDL decreased basal and stress-induced ROS levels by 73 and 72% (ECV 304) and by 76 and 43% (SK-N-BE), respectively (p < 0.01). Conclusion: These results suggest that rHDL reduces neuronal damage after onset of ischemic stroke, possibly by involving an anti-oxidative mechanism. Thus, rHDL may be a powerful neuroprotective tool for the treatment of cerebrovascular diseases.

Gene transfer with replication-deficient adenovirus is a useful tool to study vascular biology. We have reported that overexpression of endothelial nitric oxide (NO) in carotid arteries from normal rabbits augments vasorelaxation mediated by NO. In this study, we tested the hypothesis that adenovirus-mediated gene transfer of endothelial nitric oxide synthase (eNOS) improves impaired relaxation of atherosclerotic vessels. We used 2 replication-deficient adenoviruses: AdeNOS, which carries cDNA for eNOS, and Adbetagal, which expresses beta-galactosidase. Common carotid arteries from 10 New Zealand White (NZW; plasma cholesterol, 79+/-13 mg/dL) and 10 Watanabe heritable hyperlipidemic (WHHL; plasma cholesterol, 452+/-39 mg/dL) rabbits were incubated in organ culture with AdeNOS, Adbetagal, or vehicle alone. Carotid arteries from WHHL rabbits had mild to moderate atherosclerotic lesions. Histochemical staining for beta-galactosidase and immunohistochemistry for eNOS indicated transgene expression in the endothelium and adventitia in both NZW and WHHL rabbits. Expression of eNOS determined with Western blot analysis after incubation with AdeNOS tended to be higher in vessels from WHHL rabbits than NZW rabbits. Effects of transgene expression on vascular function were examined by recording isometric tension 1 day after transduction. After precontraction with phenylephrine, acetylcholine produced significantly less relaxation in vessels from WHHL rabbits than in vessels from NZW rabbits. Relaxation in response to acetylcholine was greater in carotid arteries from both NZW and WHHL rabbits that were transfected with AdeNOS than in vessels treated with vehicle or Adbetagal. Vasorelaxation in response to acetylcholine was inhibited by Nomega-nitro-L-arginine. Responses to sodium nitroprusside were similar after treatment with vehicle alone, Adbetagal, or AdeNOS in both groups of rabbits. Thus, overexpression of eNOS with an adenoviral vector improves impaired NO-mediated relaxation in atherosclerotic arteries.