Docosanoids Promote Neurogenesis and Angiogenesis, Blood-Brain Barrier Integrity, Penumbra Protection, and Neurobehavioral Recovery After Experimental Ischemic Stroke.

Docosahexaenoic acid (DHA) and neuroprotectin D1 (NPD1) are neuroprotective after experimental ischemic stroke. To explore underlying mechanisms, SD rats underwent 2 h of middle cerebral artery occlusion (MCAo) and treated with DHA (5 mg/kg, IV) or NPD1 (5 µg/per rat, ICV) and vehicles 1 h after. Neuro-behavioral assessments was conducted on days 1, 2, and 3, and on week 1, 2, 3, or 4. BrdU was injected on days 4, 5, and 6, immunohistochemistry was performed on week 2 or 4, MRI on day 7, and lipidomic analysis at 4 and 5 h after onset of stroke. DHA improved short- and long-term behavioral functions and reduced cortical, subcortical, and total infarct volumes (by 42, 47, and 31%, respectively) after 2 weeks and reduced tissue loss by 50% after 4 weeks. DHA increased the number of BrdU+/Ki-67+, BrdU+/DCX+, and BrdU+/NeuN+ cells in the cortex, subventricular zone, and dentate gyrus and potentiated NPD1 synthesis in the penumbra at 5 h after MCAo. NPD1 improved behavior, reduced lesion volumes, protected ischemic penumbra, increased NeuN, GFAP, SMI-71-positive cells and vessels, axonal regeneration in the penumbra, and attenuated blood-brain barrier (BBB) after MCAo. We conclude that docosanoid administration increases neurogenesis and angiogenesis, activates NPD1 synthesis in the penumbra, and diminishes BBB permeability, which correlates to long-term neurobehavioral recovery after experimental ischemic stroke.

Robust docosahexaenoic acid-mediated neuroprotection in a rat model of transient, focal cerebral ischemia.

BACKGROUND AND PURPOSE: Docosahexaenoic acid (DHA; 22:6n-3), an omega-3 essential fatty acid family member, is the precursor of neuroprotectin D1, which downregulates apoptosis and, in turn, promotes cell survival. This study was conducted to assess whether DHA would show neuroprotective efficacy when systemically administered in different doses after middle cerebral artery occlusion (MCAo) in rats. METHODS: Sprague-Dawley rats were anesthetized with isoflurane and subjected to 2 hour of MCAo. Animals were treated with either DHA (low doses=3.5 or 7 mg/kg; medium doses=16 or 35 mg/kg; and high dose=70 mg/kg) or an equivalent volume of saline intravenously 3 hours after MCAo onset. Neurologic status was evaluated during occlusion (60 minutes) and on days 1, 2, 3, and 7 after MCAo. Seven days after MCAo, brains were perfusion-fixed, and infarct areas and volumes were determined. RESULTS: Only the low and medium doses of DHA significantly improved the neurologic score compared with vehicle-treated rats at 24 hours, 48 hours, 72 hours, and 7 days. DHA markedly reduced total corrected infarct volume in all treated groups compared with vehicle-treated rats (3.5 mg/kg, 26+/-9 mm(3); 7 mg/kg, 46+/-12 mm(3); 16 mg/kg, 37+/-5 mm(3); and 35 mg/kg, 34+/-15 mm(3) vs vehicle, 94+/-12 mm(3)). Cortical and striatal infarct volumes were also significantly reduced by treatment with DHA. No neuroprotective effects were observed with 70 mg/kg DHA. CONCLUSIONS: We conclude that DHA experimental therapy at low and medium doses improves neurologic and histologic outcomes after focal cerebral ischemia and might provide benefits in patients after ischemic stroke.

Docosahexaenoic acid complexed to albumin elicits high-grade ischemic neuroprotection.

BACKGROUND AND PURPOSE: High-dose human albumin therapy is strongly neuroprotective in models of brain ischemia and trauma and is currently being studied in a pilot-phase clinical stroke trial. Among its actions in ischemia, albumin induces the systemic mobilization of n-3 polyunsaturated fatty acids and may help to replenish polyunsaturated fatty acids lost from neural membranes. METHODS: We complexed 25% human albumin to docosahexaenoic acid (DHA; 22:6n-3) and compared its neuroprotective efficacy with that of native albumin in rats with 2-hour focal ischemia produced by intraluminal suture-occlusion of the middle cerebral artery. RESULTS: In animals treated with DHA-albumin, 0.63 g/kg, the improvement in neurobehavioral scores at 72 hours significantly exceeded that of other treatment groups, and the extent of histological protection (86% reduction in cortical infarction) was highly significant and tended to surpass the degree of cortical protection produced by native albumin at 1.25 g/kg (65%). DHA-albumin 0.63 g/kg, but not native albumin, also significantly reduced subcortical infarction and markedly diminished brain swelling. Lipidomic analysis of DHA-albumin-treated postischemic brains revealed a large accumulation of the neuroprotective DHA metabolite, 10,17S-docosatriene, in the ipsilateral hemisphere. CONCLUSIONS: The high-grade neuroprotection afforded by the DHA-albumin complex at relatively low albumin doses is clinically advantageous in that it might reduce the likelihood of acute intravascular volume overload and congestive heart failure sometimes induced when patients with compromised cardiovascular function are treated with high-dose albumin.

Stilbazulenyl nitrone, a novel antioxidant, is highly neuroprotective in focal ischemia.

Azulenyl nitrones are novel chain-breaking antioxidants with low oxidation potentials and high lipophilicity-properties favoring their efficacy as neuroprotectants. We tested the second-generation azulenyl nitrone, stilbazunenlyl nitrone (STAZN), in focal ischemic stroke. Physiologically monitored rats received 2 hours of middle cerebral artery occlusion by intraluminal suture, resulting in substantial cortical and striatal infarcation. Neurobehavior was quantified on a standard battery, and brains were perfusion-fixed for quantitative histopathology at 3 days. In 3 independent series, rats were treated at either 2h + 4h, or 2h + 4h + 24h + 48h, after onset of ischemia; vehicle-treated rats received dimethylsulfoxide or saline. All animals (n = 52) developed high-grade neurological deficits (score 11 of 12) during ischemia, which improved, in STAZN-treated rats, within 1-1.5 h of the initial dose and fell to a median score of 3 at 72 h, compared to 8 in vehicle rats. STAZN treatment reduced mean cortical infarct volume by 64-97%, and total infarct volume by 42-72%. In over one-half of STAZN-treated animals, cortical infarction was virtually abolished. Regression analysis predicted that STAZN would confer approximately 50% cortical neuroprotection even in the most severely affected cases. The potency of STAZN was orders-of-magnitude greater than other nitrones such as NXY-059. These results suggest that STAZN has great promise for ischemic stroke.