Few studies have examined the signaling pathways that contribute to early brain injury after subarachnoid hemorrhage (SAH). Using a rat SAH model, the authors explored the role of vascular endothelial growth factor (VEGF) and mitogen-activation protein kinase (MAPK) in early brain injury. Male Sprague-Dawley rats (n = 172) weighing 300 to 350 g were used for the experimental SAH model, which was induced by puncturing the bifurcation of the left anterior cerebral and middle cerebral arteries. The blood-brain barrier (BBB), brain edema, intracranial pressure, and mortality were evaluated at 24 hours after SAH. The phosphorylation of VEGF and different MAPK subgroups (ERK1/2, p38, and JNK) were examined in both the cortex and the major cerebral arteries. Experimental SAH increased intracranial pressure, BBB permeability, and brain edema and produced high mortality. SAH induced phosphorylation of VEGF and MAPKs in the cerebral arteries and, to a lesser degree, in the cortex. PP1, an Src-family kinase inhibitor, reduced BBB permeability, brain edema, and mortality and decreased the phosphorylation of VEGF and MAPKs. The authors conclude that VEGF contributes to early brain injury after SAH by enhancing the activation of the MAPK pathways, and that the inhibition of these pathways might offer new treatment strategies for SAH.

Apoptosis in the endothelium of major cerebral arteries may play a role in the initiation and maintenance of cerebral vasospasm after subarachnoid hemorrhage (SAH). We tested the therapeutic effect of caspase inhibitors on endothelial apoptosis and on cerebral vasospasm in an established dog double-hemorrhage model. Thirty-one mongrel dogs were divided into five groups: control; SAH; SAH treated with vehicle [DMSO]; SAH treated with Ac-DEVD-CHO [a specific caspase-3 inhibitor]; and SAH treated with Z-VAD-FMK [a broad caspase inhibitor]. The inhibitors (100 microM) were injected into the cisterna magna daily from Day 0 through Day 3. Angiography was performed on Day 0 and Day 7. Histology, TUNEL staining, and immunohistochemistry were conducted on basilar arteries collected on Day 7 after SAH. Positive staining of TUNEL, poly(ADP)-ribose polymerase (PARP), caspase-3, and caspase-8 was observed in the endothelial cells of the spastic arteries. Double fluorescence labeling demonstrated co-localization of TUNEL with caspase-3 and TNFalpha receptor-1 (TNFR1). Ac-DEVD-CHO and Z-VAD-FMK prevented endothelial apoptosis and reduced angiographic vasospasm. The mechanism of apoptosis in endothelial cells involves TNFR1 and the caspase-8 and caspase-3 pathways. Caspase inhibitors may have potential in the treatment of cerebral vasospasm.

jective of the present study was to examine the role of the angiotensin II type 1 receptor (AT1-R) in the diabetes-aggravated oxidative stress and brain injury observed in a rat model of combined diabetes and focal cerebral ischemia. Diabetes was induced by an injection of streptozotoxin (STZ; 55 mg/kg iv) at 8 wk of age. Two weeks after the induction of diabetes, some animals received continuous subcutaneous infusion of the AT1-R antagonist candesartan (0.5 mg ⅐ kg Ϫ1 ⅐ day Ϫ1 ) for 14 days. Focal cerebral ischemia, induced by middle cerebral artery occlusion/reperfusion (MCAO), was conducted at 4 wk after STZ injection. Male Sprague-Dawley rats (n ϭ 189) were divided into five groups: normal control, diabetes, MCAO, diabetes ϩ MCAO, and diabetes ϩ MCAO ϩ candesartan. The major observations were that 1) MCAO produced typical cerebral infarction and neurological deficits at 24 h that were accompanied by elevation of NAD(P)H oxidase gp91 phox and p22 phox mRNAs, and lipid hydroperoxide production in the ipsilateral hemisphere; 2) diabetes enhanced NAD(P)H oxidase gp91 phox and p22 phox mRNA expression, potentiated lipid peroxidation, aggravated neurological deficits, and enlarged cerebral infarction; and 3) candesartan reduced the expression of gp91 phox and p22 phox , decreased lipid peroxidation, lessened cerebral infarction, and improved the neurological outcome. We conclude that diabetes exaggerates the oxidative stress, NAD(P)H oxidase induction, and brain injury induced by focal cerebral ischemia. The diabetes-aggravated brain injury involves AT1-Rs. We have shown for the first time that candesartan reduces brain injury in a combined model of diabetes and cerebral ischemia.angiotensin type 1 receptor antagonist IT HAS BEEN ESTABLISHED THAT diabetes is a risk factor for cerebral ischemia, and the relative risk of cerebral ischemia in diabetic patients is approximately twice as much as in patients without diabetes (6,15,28). In addition, diabetes is strongly related to early brain injury and to the poor outcome after cerebral ischemia (10,28,54). Clinical studies on diabetic patients showed that hyperglycemia augments brain lesions associated with cerebral ischemia (29,47). In animal models of cerebral ischemia, hyperglycemic animals suffered greater neurological deficit with extensive brain damage and widespread necrosis than nonhyperglycemic animals (17, 53). One of the mechanisms of diabetes-enhanced brain injury is oxidative stress caused by hyperglycemia (58).Reactive oxygen species-mediated oxidative stress is believed to produce tissue injury in wide variety of diseases, including diabetes (58). Several enzymes, especially NAD(P)H oxidase, are recognized as being potentially able to produce reactive oxygen species during diabetes (31). NAD(P)H oxidase consists of five major subunits: a plasma membrane spanning cytochrome b 558 composed of the large subunit gp91 phox , the smaller p22 phox subunit, and three cytosolic compounds (p47 phox , p67 phox , and p40 phox ) (19,30). When cells are stimulated, th...

SAH at the skull base induced P-selectin- and oxygen radical-mediated platelet-leukocyte-endothelial cell interactions in venules at the cerebral surface. These early inflammatory and prothrombogenic responses may cause a whole-brain injury immediately after SAH.

This prospective study showed that continuation of antithrombotics did not increase the bleeding risk after upper gastrointestinal endoscopic biopsy.

The tyrosine kinase Src is an important upstream regulator of MAPK, and inhibition of Src might offer a new therapy in the management of cerebral vasospasm.

Therapeutic outcome in head and neck squamous cell carcinoma (HNSCC) is poor in most advanced cases. To improve therapeutic efficiency, novel therapeutic targets and prognostic factors must be discovered. Our studies have identified several G protein-coupled receptors (GPCRs) as promising candidates. Significant epigenetic silencing of GPCR expression occurs in HNSCC compared with normal tissue, and is significantly correlated with clinical behavior. Together with the finding that GPCR activity can suppress tumor cell growth, this indicates that GPCR expression has potential utility as a prognostic factor. In this review, we discuss the roles that galanin receptor type 1 (GALR1) and type 2 (GALR2), tachykinin receptor type 1 (TACR1), and somatostatin receptor type 1 (SST1) play in HNSCC. GALR1 inhibits proliferation of HNSCC cells though ERK1/2-mediated effects on cell cycle control proteins such as p27, p57, and cyclin D1, whereas GALR2 inhibits cell proliferation and induces apoptosis in HNSCC cells. Hypermethylation of GALR1, GALR2, TACR1, and SST1 is associated with significantly reduced disease-free survival and a higher recurrence rate. Although their overall activities varies, each of these GPCRs has value as both a prognostic factor and a therapeutic target. These data indicate that further study of GPCRs is a promising strategy that will enrich pharmacogenomics and prognostic research in HNSCC.

Background and Purpose-We report a modified 4-vessel occlusion (4VO) rat model. Method-We used a 1-stage anterior approach for making bilateral hemispheric ischemia. Results-Modified 4VO method decreased cerebral blood flow to 12% to 14% of baseline levels. 7 However, incomplete occlusion occurs, and the 2-stage surgery at the 24-hour interval may lead to preconditioning effect. Several modified models produce a more consistent reduction in cerebral blood flow (CBF), but the surgery itself is invasive and technically demanding. 4,9 In the present study, we show a 1-stage anterior approach to occlude the common carotid arteries (CCAs) and vertebral arteries (VAs) to be a safe, easy, less invasive technique for making bilateral hemispheric ischemia. Conclusion-This Materials and MethodsThis protocol was approved by the animal care and use committee at Louisiana State University Health Sciences Center in Shreveport. A total of 33 male Sprague-Dawley rats weighing between 340 and 390 g were assigned to 3 groups: sham operated (nϭ6); arteries occluded for 10 minutes (10-minute group; nϭ12); and arteries occluded for 30 minutes (30-minute group; nϭ15).Rats were anesthetized with ␣-chloralose (40 mg/kg IP) and urethane (400 mg/kg IP) and placed in the supine position. A 2.5-cm midline skin incision was made on the neck, and with the aid of a surgical microscope, the subcutaneous connective tissue and muscles were gently retracted to expose the trachea and thyroid (Figure 1Ba). The bilateral CCAs were isolated and 2-0 silk surgical sutures were loosely placed around the arteries as landmarks for applying microvascular clips (No. 18055-04; Fine Science Tools). The longus colli muscle was then exposed by retracting the trachea and esophagus to the right side ( Figure 1Bb). This allowed for the anterior tubercle of the atlas to be identified through the muscle, thereby verifying the operating location (Figure 1Aa, 1Ad, and 1Ae). By exposing the cervical vertebral bodies from the atlas to the upper half of the fourth cervical vertebral body, the bilateral VAs were visualized between the second and third transverse processes (Figure 1Aa, 1Ab, and 1Ad). The VAs were then isolated carefully without interrupting blood flow (Figure 1Bc). The right CCA, left CCA, right VA, and left VA were occluded in turn with microvascular clips. The arteries were allowed to reperfuse 10 or 30 minutes after occlusion. Animals with sham operation underwent the same procedures with the exception of the application of microvascular clips.The CBF in the right hemisphere was measured continuously with a laser Doppler flowmeter (PF5010; PERIMED; nϭ3) as described previously. 6 Morphology (Nissl staining) was conducted as described, 6 and the number of intact cells was counted at 10 regions of interest in each hemisphere. Neurological deficits were measured before the surgery and 24, 48, and 72 hours after bilateral hemispheric ischemia with the modified Garcia scoring system. 3 Results were expressed as meanϮSEM. The neurological score was performe...