Infarct Volume In Group Research Articles

Abstract 338: Statin Therapy is Associated with Decreased Plaque Instability in Symptomatic Carotid Atherosclerotic Plaque: a Clinicopathological Analysis

Background: Statin therapy has been shown to deplete atherosclerotic plaque instability in human carotid arteries by various imaging modalities or in animal models by pathological analysis. However, whether statin therapy attenuates plaque instability in human carotid plaque has not been fully described in a pathological analysis. The aim of this study was to analyze pathologically the possible relationships between statin therapy and plaque stability in patients undergoing carotid endarterectomy (CEA). Methods: Among consecutive 79 patients with advanced carotid artery stenosis (>70%) between May 2015 and February 2017, 66 patients without statin therapy (group 1) and 13 patients with statin therapy (group 2) were analyzed. The specimens were stained with hematoxylin/eosin and elastica-Masson. Immunohistochemistry was performed, using an endothelial specific antibody to CD31, CD34 and PDGFRβ. Results: Plaques from group 2 had significantly less plaque rupture (P=0.009), lumen thrombus (P=0.009), inflammatory cells (P=0.008), intraplaque hemorrhage (P=0.030) and intraplaque microvessels (P<0.001), compared with those from group 1. Among stroke patients with infarct size >1.0 cm 3 in MRI, the mean infarct volume in group 2 (4.2 ± 2.5 cm 3 ) was significantly smaller than that in group 1 (8.2 ± 7.1 cm 3 , p = 0.031). There was no significant difference in the mean concentration of low-density lipoprotein cholesterol between group 1 and group 2 (121 ± 32 mg/dl vs. 105 ± 37 mg/dl, P=0.118). Conclusions: This clinicopathological analysis of carotid atherosclerotic plaque suggests that statin therapy is associated with decreased plaque instability, which might result in smaller infarct volume in stroke patients undergoing CEA. This plaque stability might be derived from pleiotropic effect beyond lipid lowering of statin therapy.

Dose finding study of intravenous magnesium sulphate in transient focal cerebral ischemia in rats

During many neurovascular procedures temporary occlusion of cerebral arteries is inevitable. Neuroprotective drugs may reduce the risk of cerebral infarction in this situation. Increasing evidence indicates neuroprotective properties of magnesium in cerebral ischemia. Previous experimental studies on the neuroprotective efficacy of magnesium-treatment in transient focal ischemia provide widely differing results using different magnesium doses and treatment-regimens. The present study was conducted to find the maximum protective dose of intravenous magnesium sulphate in a rat model of transient focal ischemia. 45 male Sprague-Dawley rats were subjected to 90 minutes of middle cerebral artery occlusion (MCAO) by an intraluminal thread. Animals were randomly assigned to one of 4 treatment arms: (1) vehicle (2) MgSO(4) 1x0.75 mmol/kg (3) MgSO(4) 2x1 mmol/kg (4) MgSO(4) 1 mmol/kg+0.5 mmol/kg/h. Local cortical blood flow (LCBF) was continuously measured by laser-Doppler flowmetry. Functional deficits were quantified daily, infarct volumes were assessed histologically after 7 days. Magnesium serum levels below 3 mmol/l were well tolerated by the animals. Above 3 mmol/l cardiodepressive effects limited neuroprotection. Total infarct volumes in groups 3 and 4 were significantly reduced by 32% and 42%, respectively, compared to controls. Postoperative neurological recovery was significantly improved in magnesium-treated groups. Continuous magnesium-administration with stable serum concentrations between 2 and 3 mmol/l offered the best protection and was well tolerated. Serum concentrations above 3 mmol/l should not be exceeded. An elevation of magnesium serum levels could be useful for brain tissue protection during procedures which are prone to the risk of temporary vessel occlusion.

Coadministration of bone marrow cells and an inhibitor of apoptosis (Z-VAD) promotes bone marrow cell survival and neurological functional recovery after focal cerebral ischemia in adult rat

P222 Most bone marrow cells (BMCs) transplanted into the ischemic brain of adult rodents die shortly after they are grafted, similar to the 90%-95% of the fetal cells that die after transplantation into Parkinson s patients. We tested whether coadministration of BMCs and Z-Val-Ala-DL-Asp-fluoromethylketone (Z-VAD), an inhibitor of apoptosis, into the ischemic boundary zone of the striatum and the cortex in rat brain promotes BMC survival. Adult Wistar rats were subjected to transient (2 h) middle cerebral artery occlusion (MCAo). At 1 d after ischemia, saline (n=9, Group 1); BMCs (1x10 6 in 10 :l, n=8, Group 2); or BMCs with Z-VAD (50 nM/ml, n=4, Group 3) were injected into brain. BMCs were harvested from donor adult rats injected with bromodeoxyuridine (BrdU, as a tracer). Rats were subjected to rotarod-motor and adhesive-removal somatosensory functional tests before MCAo and at 1 and 7 d after MCAo. Rats in Group 3 exhibited significant improvement (10.3±2.6 seconds, p<0.05) on the adhesive-removal test at 7 d, compared with those in Group 1 (29.3±9.4 seconds) and Group 2 (21.3±5.5 seconds), respectively. Immunohistochemistry staining was employed to identify BrdU-BMCs, and TUNEL staining was used to identify in situ DNA fragmentation of apoptotic cells. Even though the infarct volume in Group 3 (29.9±9.2%) did not change significantly, compared with Group 1 (34.3±4.0%) and Group 2 (26.6±3.8%); the number of BrdU-BMCs (88,200±7,400, ∼8.8% of 10 6 transplanted cells) increased significantly (p<0.05) in rats in Group 3, compared with that in Group 2 (31,700±9,100, ∼3.2% of 10 6 cells) at 7 d. In the grafting areas, apoptotic cells were less clustered (<90 vs.>240 per region) and apoptotic cells were significantly decreased (12.3±1.7/mm 2 vs. 25.9±2.1/mm 2 , ∼47%, p<0.05). Our data suggest that intracerebral coadministration of bone marrow cells and inhibitors of apoptosis enhance cellular survival of bone marrow cells and improves neurological functional recovery after cerebral ischemia.

ラット局所脳虚血モデルにおける低体温療法の脳保護効果増強の試み 低体温＋免疫抑制剤ＦＫ５０６併用療法

Hypothermia has a neuroprotective effect for ischemia. The aim of this study was, therefore, to determine whether mild hypothermia (35°C) would enhance neuroprotecive effects of immunosuppressant FK 506 for focal ischemia. The left MCAO were occluded for 2 h by intraluminal suture and reperfused for 24 h. Animals were randomly devided into the following four groups. (I) vehicle-treated, normothermic (37°C) group (II) vehicle-treated, mild hypothermic (35°C) group (III) FK 506-treated, normothermic (37°C) group (IV) FK 506-treated, mild hypothermic (35°C) group. FK 506-treated animals received a single injection of FK 506 (0.3 mg/kg) intravenously 120 min after the onset of ischemia, while vehicle-treated groups received same dose of vehicle. The cortical and striatal infarct volume in group IV was significantly reduced compared with that in group I (p<0.001), whereas there was no significant difference between group II or III and group I. Moreover, edema volume in group IV was significantly smaller than that in group I (p<0.05). These results demonstrate that a combined therapy with mild hypothermia (35°C) and FK 506, each has no neuroprotective effects alone, significantly reduces the ischemic brain damage and enhances neuroprotecive actions for focal ischemia in rats.

Synergistic effects of citicoline and MK-801 in temporary experimental focal ischemia in rats.

Citicoline, a naturally occurring precursor of phosphatidylcholine, is neuroprotective and is currently being assessed in clinical trials. To evaluate potential synergistic neuroprotective effects of prolonged citicoline treatment and early N-methyl-D-aspartate (NMDA) antagonist therapy, suboptimal treatment regimens of citicoline and MK-801 were tested alone and in combination in a rat model of temporary focal ischemia. Four groups of Sprague-Dawley rats (n = 12 per group) underwent 90 minutes of temporary middle cerebral artery occlusion (MCAO) with the suture model. Animals were randomly and blindly assigned to one of four treatment groups: (1) saline, vehicle; (2) MK-801, 0.5 mg/kg IV bolus at 60 minutes after MCAO followed by saline 1 mL/kg IP daily for 7 days; (3) saline IV at 60 minutes after MCAO followed by citicoline 250 mg/kg IP daily for 7 days; or (4) both MK-801 and citicoline (daily for 7 days) active treatment. Triphenyltetrazolium chloride staining was used to assess postmortem infarct volume. Neurological scores were determined daily. Premature mortality between days 2 and 4 was 33.3% in group 1, 41.7% in groups 2 and 3, and 25.0% in group 4. Mean corrected infarct volume was significantly reduced in group 4 compared with the others (175.2 +/- 89.3 mm3 in group 1, 179.1 +/- 78.5 mm3 in group 2, 163.9 +/- 73.7 mm3 in group 3, and 84.7 +/- 56.8 mm3 in group 4 [P < .02, ANOVA and P < .05, Scheffé's test for group 1 versus group 4]). Mean infarct volume in animals dying prematurely was significantly (P < .05, Student's t test) larger in group 1 than those surviving for 7 days (247.2 +/- 89.5 versus 139.2 +/- 68.2 mm3), but there was no significant difference in infarct volume in groups 2, 3, and 4 between animals dying prematurely and those surviving for 7 days. These results demonstrate synergistic neuroprotective effects of citicoline and an NMDA antagonist in temporary experimental focal ischemia.

Protective effect of nilvadipine on focal cerebral ischemia in spontaneously hypertensive rats.

The protective effect of nilvadipine, a Ca2+ antagonist, on cerebral ischemia was investigated in spontaneously hypertensive rats. The 12-week-old animals were treated for 7 days with either nilvadipine or vehicle using osmotic pumps implanted subcutaneously. Group 1 animals (n = 10) received the vehicle, and Group 2 (n = 10) and 3 animals (n = 10) received 1 and 3 mg/kg/day nilvadipine, respectively. The left middle cerebral artery was occluded under halothane anesthesia on the 6th day of treatment, and neuropathological outcomes were quantified 24 hours later. The systolic blood pressure measured before occlusion decreased to 137 +/- 9 mmHg (Group 2) and 130 +/- 9 mmHg (Group 3), compared to 189 +/- 12 mmHg for Group 1 (p < 0.05). The percentage infarct volumes in Groups 1-3 were 39 +/- 3%, 37 +/- 2%, and 34 +/- 3%, respectively (p < 0.05, Groups 1 vs. 3). Therefore, nilvadipine decreased the infarct size dose-dependently. Nilvadipine has a protective effect against cerebral ischemia in rats with chronic hypertension. Neuropathological findings suggest that nilvadipine may act at the ischemic penumbra. Nilvadipine may have the additional benefit of reducing the consequences of a possible later stroke in patients with hypertension (one of the risk factors for stroke).