History of Vasospasm Research in Japan: Commemoration of Professor Tomio Ohta.

In the 1960s Professor Setsuro Ebashi, a physiologist from the University of Tokyo, discovered calcium ion plays a pivotal role in muscle contraction for the first time. However, he was confounded by icy neglect of the society of physiologists. The International Conference on Physiology was held in Boston in 1962, and Dr. Ebashi and his coworker Dr. Anne Mary Weber gave a talk about calcium signal which is a key mechanism for regulating muscle contraction. Every single attendant stood against their theory and even laughed at them.

[Pontine Hemorrhage Suspected due to Dural Arteriovenous Fistula at the Craniocervical Junction:A Case Report].

Dural arteriovenous fistulas occurring at the craniocervical junction(CCJd-AVF)are uncommon; however, they demonstrate a wide range of clinical presentations. We describe the case of a patient with pontine hemorrhage suspected due to CCJd-AVF. A 68-year-old man presented to our hospital with a sudden onset of left hemiparesis. Cranial computed tomography(CT)revealed pontine and subarachnoid hemorrhage. Magnetic resonance imaging, as well as MR, CT, and left vertebral angiograms were performed and showed a CCJd-AVF in addition to a varix coincident with the hematoma cavities. The patient was successfully treated using surgical drainer clipping. A CCJd-AVF presenting concomitantly with a pontine hemorrhage is extremely rare. Careful assessment of the anatomical relationship between the skull base and the surrounding vascular structures is important to plan neurosurgical procedures for direct interruption of the draining vein. Three-dimensional CT angiography is a useful modality that facilitates visualization of complex and anomalous anatomical structures.

Cerebral Infarction After Aneurysmal Subarachnoid Hemorrhage.

Predictors for cerebral infarction, an important cause of poor outcome after aneurysmal subarachnoid hemorrhage (SAH), were examined. This study used data from the Prospective Registry of Subarachnoid Aneurysms Treatment (PRESAT) cohort, which included 579 patients whose ruptured aneurysms were treated with either clipping or coiling within 12 days of onset. Patient, clinical, radiographic, and treatment variables associated with cerebral infarction were determined. Ruptured aneurysms were clipped in 282 patients and coiled in 297 patients. Cerebral infarction occurred in 162 patients (28.0 %): 101 patients by cerebral vasospasm, 34 patients by clipping, and 33 patients by coiling. Univariate analyses showed that significant factors associated with cerebral infarction development were Fisher computed tomography (CT) group 3 on admission, premature aneurysm rupture during clipping procedure, cerebrospinal fluid drainage, symptomatic vasospasm, endovascular treatment for vasospasm, and shunt-dependent hydrocephalus. Multivariable logistic regression analyses showed that cerebral infarction was significantly associated with Fisher CT group 3 on admission, larger aneurysm dome size, ruptured posterior circulation aneurysms, premature aneurysm rupture during clipping procedure, symptomatic vasospasm, and infection, while endovascular treatment for vasospasm significantly decreased the development of cerebral infarction. The most important potentially treatable factor associated with cerebral infarction was symptomatic vasospasm.

The Role of Matricellular Proteins in Brain Edema after Subarachnoid Hemorrhage.

Accumulated evidence suggests that blood-brain barrier disruption or brain edema is an important pathologic manifestation for poor outcome after aneurysmal subarachnoid hemorrhage. Many molecules may be involved, acting simultaneously or at different stages during blood-brain barrier disruption via multiple independent or interconnected signaling pathways. Matricellular protein is a class of nonstructural, secreted, and multifunctional extracellular matrix proteins, which potentially mediates brain edema formation. This study reviews the role of osteopontin and tenascin-C, representatives of matricellular proteins, in the context of brain edema formation after subarachnoid hemorrhage in both clinical and experimental settings.

Risk factors for vasospasm-induced cerebral infarct when both clipping and coiling are equally available.

INTRODUCTION: Vasospasm-induced cerebral infarct is still a significant cause of poor outcome after aneurysmal subarachnoid hemorrhage (SAH). MATERIALS AND METHODS: In 537 patients of the Prospective Registry of Subarachnoid Aneurysms Treatment cohort, ruptured aneurysms were treated either microsurgically or endovascularly judged by the attending neurosurgeon to be appropriate for the individual patient within 3 days of onset. Factors for vasospasm-induced cerebral infarct were examined. RESULTS: Clipping (273 patients) was preferably performed for middle cerebral artery aneurysms, while coiling (264 patients) was preferred for larger, internal carotid artery and posterior circulation aneurysms. After aneurysmal obliteration, cerebrospinal fluid drainage was performed more in clipped patients, and antithrombotic treatment was performed more in coiled patients. Vasospasm-induced cerebral infarct occurred in 17.7 %, and multivariable logistic regression showed that vasospasm-induced cerebral infarct increased the odds of poor outcome by a factor of 5.2 (adjusted odds ratio, 5.2; 95 % confidence interval, 2.8-9.8; P < 0.001). Multivariate analyses showed that vasospasm-induced cerebral infarct was significantly associated with admission World Federation of Neurosurgical Societies grade IV-V, Fisher computed tomography (CT) group 3-4, and ruptured middle cerebral artery aneurysms. CONCLUSIONS: New treatment strategies for vasospasm-induced cerebral infarct are needed, especially for ruptured middle cerebral artery aneurysm cases associated with massive SAH.

Effects of tenascin-C on early brain injury after subarachnoid hemorrhage in rats.

BACKGROUND AND PURPOSE: We previously reported that tenascin-C (TNC), a matricellular protein, was involved in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH), but the role of TNC in early brain injury (EBI) is unknown. This study assessed whether inhibition of TNC upregulation in brain by imatinib mesylate (imatinib), an inhibitor of the tyrosine kinases of platelet-derived growth factor receptors, prevents EBI after experimental SAH. METHODS: Rats were assigned to sham, SAH plus vehicle, and SAH plus imatinib groups (n = 4 per group). Imatinib (50 mg/kg body weight) was administered intraperitoneally to rats undergoing SAH by endovascular perforation, and EBI was evaluated using terminal deoxynucleotidyl transferase-mediated uridine 5-triphosphate-biotin nick end-labeling staining at 24 h after SAH. Imatinib-treated SAH rats were also treated by a cisternal injection of recombinant TNC. RESULTS: SAH upregulated TNC and caused EBI. Imatinib treatment suppressed both TNC upregulation and EBI at 24 h. Recombinant TNC reinduced EBI in imatinib-treated SAH rats. CONCLUSIONS: TNC may be involved in the pathogenesis of EBI after SAH.

Tenascin-C is a possible mediator between initial brain injury and vasospasm-related and -unrelated delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

INTRODUCTION: Tenascin-C (TNC), a matricellular protein, exerts diverse functions, including tissue remodeling and apoptosis, and is induced in cerebrospinal fluid (CSF) after aneurysmal subarachnoid hemorrhage (SAH). The purpose of this study was to examine the relationships among CSF TNC levels, initial brain injury, delayed cerebral ischemia (DCI), and vasospasm after SAH. METHODS: CSF TNC levels were measured in 30 patients with aneurysmal SAH of Fisher computed tomography (CT) group III who were treated microsurgically or endovascularly with CSF drainage within 24 h of SAH. Admission World Federation of Neurosurgical Societies (WFNS) grade was supposed to indicate the severity of initial brain injury. Cerebral vasospasm was defined as narrowed (≥ 25 %) cerebral arteries demonstrated by angiography. DCI was defined as any neurological deterioration presumed related to ischemia that persisted for ≥ 1 h. RESULTS: Higher CSF TNC levels were correlated with worse admission WFNS grades. Vasospasm was aggravated with higher TNC levels. DCI occurred regardless of the degree of vasospasm but was associated with TNC induction. Multivariate analyses showed that higher TNC levels and vasospasm were independent predictors of DCI occurrence. CONCLUSIONS: SAH (initial brain injury) that is more severe induces more TNC, which may cause the subsequent development of both vasospasm and vasospasm-unrelated secondary brain injury, leading to DCI.

Vasoconstrictive effect of tenascin-C on cerebral arteries in rats.

BACKGROUND AND PURPOSE: The authors have reported that tenascin-C (TNC), a matricellular protein, is induced after subarachnoid hemorrhage (SAH), associated with cerebral vasospasm. In this study, we examined whether TNC alone causes cerebral vasospasm-like constriction of the intracranial internal carotid arteries (ICAs) in rats, focusing on the p38 mitogen-activated protein kinase (MAPK)-mediated mechanisms. METHODS: First, we injected 10 µg of TNC into the cisterna magna of healthy rats and studied morphologically whether TNC caused constriction of the left ICA at 24-72 h after administration. Second, we examined the effect of SB203580 (a p38 MAPK inhibitor) on the vessel diameter of the left ICA in healthy rats at 24 h. Third, we evaluated the effect of SB203580 on TNC-induced constriction of the left ICA in healthy rats at 24 h. RESULTS: TNC significantly induced cerebral vasospasm-like angiographic constriction of the left ICAs, which continued at least for 72 h. SB203580 itself had no effect on the diameter of normal ICAs, but abolished the TNC-induced vasoconstrictive effect on the left ICA. CONCLUSION: These findings show that TNC causes left ICA constriction via activation of p38 MAPK, resembling post-SAH vasospasm, and suggest the possible involvement of TNC in the pathogenesis of cerebral vasospasm.

Tenascin-C induces prolonged constriction of cerebral arteries in rats.

Tenascin-C (TNC), a matricellular protein, is induced in association with cerebral vasospasm after subarachnoid hemorrhage. The aim of this study was to assess the vasoconstrictive effects of TNC and its mechanisms of action on cerebral arteries in vivo. Two dosages (1 and 10µg) of TNC were administered intracisternally to healthy rats, and the effects were evaluated by neurobehavioral tests and India-ink angiography at 24, 48, and 72h after the administration. Western blotting and immunohistochemistry were performed to explore the underlying mechanisms on constricted cerebral arteries after 24h. The effects of toll-like receptor 4 (TLR4) antagonists (LPS-RS), c-Jun N-terminal kinase (JNK), and p38 inhibitors (SP600125 and SB203580) on TNC-induced vasoconstriction were evaluated at 24h. Higher dosages of TNC induced more severe cerebral arterial constriction, which continued for more than 72h. TNC administration also upregulated TLR4, and activated JNK and p38 in the smooth muscle cell layer of the constricted cerebral artery. LPS-RS blocked TNC-induced TLR4 upregulation, JNK and p38 activation, and vasoconstrictive effects. SP600125 and SB203580 abolished TNC-induced TLR4 upregulation and vasoconstrictive effects. TNC may cause prolonged cerebral arterial constriction via TLR4 and activation of JNK and p38, which may upregulate TLR4. These findings suggest that TNC causes cerebral vasospasm and provides a novel therapeutic approach against it.

Neuromelanin magnetic resonance imaging in Parkinson's disease and multiple system atrophy.

Pigmented neurons in the substantia nigra pars compacta (SNc) and locus coeruleus (LC) show decreased numbers differentially in Parkinson's disease (PD) and multiple system atrophy (MSA). Recent reports have described that fast spin-echo T1-weighted magnetic resonance imaging (MRI) by a 3-tesla machine can visualize neuromelanin-related contrast of the noradrenergic and dopaminergic neurons respectively in the LC and the SNc. Using neuromelanin MRI at 3 T, we investigated possible alterations of these catecholaminergic neurons in 32 PD and 9 MSA patients, and compared the results with those of 23 normal volunteers. The contrast ratio of the LC and SNc was decreased in MSA and PD patients, most prominently in the LC in MSA patients. The contrast ratio of the SNc was correlated with the Hoehn-Yahr stage of PD and the severity of neuroradiological abnormalities in MSA. These results indicate a potential diagnostic value of neuromelanin MRI to distinguish MSA patients from normal and PD patients.

Matricellular protein: a new player in cerebral vasospasm following subarachnoid hemorrhage.

INTRODUCTION: Matricellular protein (MCP) is a class of nonstructural and secreted extracellular matrix proteins that exert diverse functions, but its role in vascular smooth muscle contraction has not been investigated. MATERIAL AND METHODS: First, rat subarachnoid hemorrhage (SAH) models were produced by endovascular perforation and examined for tenascin-C (TNC) and osteopontin (OPN) induction (representatives of MCPs) in vasospastic cerebral arteries using immunostaining. Second, recombinant TNC (r-TNC), recombinant OPN (r-OPN), or both were injected into a cisterna magna in healthy rats, and the effects on the diameter of basilar arteries were determined using India ink angiography. RESULTS: In SAH rats, TNC immunoreactivity was markedly induced in the smooth muscle cell layers of spastic cerebral arteries on day 1 but not in control animals. The TNC immunoreactivity decreased on day 3 as vasospasm improved: OPN immunoreactivity, on the other hand, was more induced in the arterial wall on day 3. r-TNC injections caused prolonged contractions of rat basilar arteries, which were reversed by r-OPN, although r-OPN itself had no effect on the vessel diameter. CONCLUSIONS: MCPs, including TNC and OPN, may contribute to the pathophysiology of cerebral vasospasm and provide a novel therapeutic approach against it.

Role of platelet-derived growth factor in cerebral vasospasm after subarachnoid hemorrhage in rats.

BACKGROUND AND PURPOSE: The role of platelet-derived growth factor (PDGF) remains unknown in cerebral vasospasm after subarachnoid hemorrhage (SAH). In this study, we examined the effects of PDGF receptor (PDGFR) inactivation on cerebral vasospasm in the endovascular perforation model of SAH in rats. METHODS: Rats were assigned to sham, SAH plus vehicle, and SAH plus imatinib mesylate (imatinib) groups (n = 4 per group). Imatinib (50 mg/kg body weight), an inhibitor of the tyrosine kinases of PDGFR, or vehicle was administered intraperitoneally 30 min post-SAH. Vasospasm was evaluated in the left (perforation-sided) internal carotid artery by means of neurobehavioral tests, India ink angiography, and immunohistochemistry at 24 h after SAH. RESULTS: Imatinib significantly inhibited post-SAH PDGFR activation in the left internal carotid artery, in which vasospasm was significantly prevented. Animal's neurobehavior also showed a tendency to improve by imatinib treatment. CONCLUSIONS: PDGF may play an important role in the pathogenesis of vasospasm after SAH.

Imatinib mesylate prevents cerebral vasospasm after subarachnoid hemorrhage via inhibiting tenascin-C expression in rats.

Platelet-derived growth factor (PDGF) has been implicated in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage (SAH), but the mechanism remains unknown. The purpose of this study was to assess whether imatinib mesylate (imatinib), an inhibitor of the tyrosine kinases of PDGF receptors (PDGFRs), prevents cerebral vasospasm after SAH in rats, and to elucidate if tenascin-C (TNC), a matricellular protein, is involved in the mechanism. Imatinib (10 or 50 mg/kg body weight) was administered intraperitoneally to rats undergoing SAH by endovascular perforation, and the effects were evaluated by neurobehavioral tests and India-ink angiography at 24-72 h post-SAH. Western blotting and immunohistochemistry were performed to explore the underlying mechanisms in cerebral arteries at 24h post-SAH. Recombinant TNC was administered intracisternally to imatinib-treated SAH rats, and the effects were evaluated by neurobehavioral tests, India-ink angiography and immunohistochemistry at 24 h post-SAH. Both dosages of imatinib significantly prevented post-SAH neurological impairments and vasospasm at 24-72 h. SAH caused PDGFR-ß upregulation, PDGFR activation, mitogen-activated protein kinase activation, and TNC upregulation in the spastic cerebral arteries, all of which were significantly suppressed by imatinib treatment. Recombinant TNC reversed the anti-vasospastic effects and protein expression changes by imatinib. This study suggests that imatinib prevents cerebral vasospasm at least partly via inhibiting the upregulation of TNC, implying that TNC may be a new therapeutic target for post-SAH vasospasm.

Recombinant osteopontin in cerebral vasospasm after subarachnoid hemorrhage.

OBJECTIVE: Osteopontin (OPN), a pleiotropic extracellular matrix glycoprotein, has been reported to be protective against ischemic lesions, but effects of OPN on vascular functions have not been investigated. The aim of this study was to assess whether recombinant OPN (r-OPN) could prevent cerebral vasospasm after subarachnoid hemorrhage (SAH) in rats. METHODS: r-OPN was administered intraventricularly to rats undergoing SAH by endovascular perforation, and its protective effects were evaluated by measuring the diameter of cerebral arteries and neurobehavioral testing. Western blotting and immunofluorescence were performed to explore the underlying mechanisms. An integrin receptor antagonist GRGDSP or mitogen-activated protein kinase (MAPK) phosphatase (MKP)-1 small interfering RNA (siRNA) was also administered to r-OPN-treated SAH rats, and those effects were evaluated. RESULTS: Pre-SAH administration of r-OPN prevented vasospasm and neurological impairments at 24-72 hours post-SAH. r-OPN enhanced an endogenous MAPK inhibitor, MKP-1, and suppressed the phosphorylation of MAPKs, caldesmon, and heat shock protein 27 in the spastic cerebral arteries at 24 hours post-SAH. Immunofluorescence revealed that MKP-1 was induced in the arterial smooth muscle layer. GRGDSP prevented r-OPN-induced MKP-1 upregulation, and MKP-1 siRNA abolished both MAPK inactivation and anti-vasospastic effects by r-OPN. Post-SAH r-OPN treatment also prevented vasospasm. INTERPRETATION: r-OPN induced MKP-1 in the spastic cerebral arteries via binding to L-arginyl-glycyl-L-aspartate-dependent integrin receptors and prevented vasospasm after SAH. Therapeutic induction of MKP-1 may be a novel approach for the prevention and treatment of cerebral vasospasm.

Effect of recombinant osteopontin on cerebral vasospasm after subarachnoid hemorrhage in rats.

BACKGROUND: osteopontin (OPN), a pleiotropic extracellular matrix glycoprotein, has been reported to have neuroprotective effects against early brain injury after subarachnoid hemorrhage (SAH). The aim of this study is to examine if osteopontin prevents cerebral vasospasm after SAH in rats. METHOD: the endovascular perforation model of SAH was produced, and 62 rats were randomly assigned to sham + vehicle, SAH + vehicle, and SAH+ r-OPN (0.1 microg) groups. Cerebral vasospasm was evaluated by India ink angiography at 24 and 72 h after SAH, as well as neurobehavioral tests. FINDINGS: significant vasospasm and neurological impairments occurred over the observed period after SAH. r-OPN significantly prevented vasospasm in the left middle cerebral artery at 24 h and improved neurological impairments at 48 h after SAH. In other time points studied, r-OPN had a tendency toward improving both vasospasm and neurological scores, but the difference was not significant. CONCLUSIONS: this study shows that r-OPN has anti-vasospastic effects against cerebral vasospasm after SAH.

Neck clipping of paraclinoid small aneurysms.

Paraclinoid small aneurysms with a diameter less than 5 mm may be difficult to handle intraoperatively. We have encountered 9 such aneurysms among 375 cases. The most frequent location was the ophthalmic segment (n = 6) followed by the anterior wall (n = 3) of the internal carotid artery (ICA). The endovascular procedure was not suitable for this particular lesion because of the difficulty in deploying the coil across such small aneurysms. One patient with an ophthalmic segment aneurysm underwent endovascular treatment first; however, the procedure was aborted because of mechanical vasospasm. Finally the patient underwent craniotomy, and the aneurysm was successfully clipped. Two patients with anterior wall aneurysms presented with subarachnoid hemorrhage, and the blood blister-like aneurysms were clipped without sacrifice of the ICA. Five patients with unruptured aneurysms of the ophthalmic segment and one such case of the anterior wall of ICA were all clipped uneventfully. The operative procedure for these small aneurysms is deemed straightforward: (1) high attention should be paid to avoid premature rupture; (2) both the internal carotid artery and optic nerve are mobilized and the anterior clinoid process and falciform ligament are removed, then the aneurysmal neck is created; (3) the neck of the aneurysm is created by pushing the wall of the ICA slightly away during clip application; this is called the "nip on method." Although neck clipping of small aneurysms can be difficult, no efforts should be spared to accomplish direct neck clipping.

Mitogen-activated protein kinases in cerebral vasospasm after subarachnoid hemorrhage: a review.

BACKGROUND: Mitogen-activated protein kinases (MAPKs) have been implicated in the pathogenesis of cerebral vasospasm after subarachnoid hemorrhage. The goal of this review is to bring together recent diverse data concerning the roles of MAPKs in cerebral vasospasm and to consider the future research. METHOD: A review of publications in the National Library of Medicine and National Institutes of Health database was conducted in August 2009 using specific keyword search terms pertaining to subarachnoid hemorrhage and MAPKs. FINDINGS: There are nine in vitro studies and 17 in vivo studies published. Most of previous studies used MAPK inhibitors or their upstream molecule inhibitors, and showed that MAPK inhibitions prevented vasospasm. The MAPK cascade appears to interact with other signaling molecules, and MAPK may be an important final common pathway for the signaling transduction during cerebral vasospasm. However, the mechanism by which MAPK causes sustained vascular smooth muscle contraction remains unclear. In addition, the role of endogenous MAPK inhibitors, MAPK phosphatases, has not been investigated in cerebral vasospasm. CONCLUSIONS: The experimental data support the causative role of MAPK in cerebral vasospasm and warrant further research.

Subarachnoid hemorrhage causes pulmonary endothelial cell apoptosis and neurogenic pulmonary edema in mice.

OBJECTS: Neurogenic pulmonary edema (NPE) is a well-known complication of subarachnoid hemorrhage (SAH), which potentially causes a poor outcome. The aim of this study was to examine if NPE occurs in the endovascular perforation model of SAH in mice and if apoptosis contributes to NPE development after SAH in mice. METHODS: Sham-operated or SAH mice were treated with an intraperitoneal administration of vehicle or an antiapoptotic drug Z-Val-Ala-Asp-fluoromethylketone (Z-VAD-FMK) 1 h post-SAH. Pulmonary edema measurements and evaluation of apoptosis occurrence were performed on the lung at 24 h post-SAH. RESULTS: SAH caused NPE, which was associated with apoptosis of pulmonary endothelial cells. Z-VAD-FMK significantly prevented apoptosis and NPE. CONCLUSIONS: Pulmonary endothelial cell apoptosis contributes to the pathophysiology of NPE after SAH in mice.

STA-MCA bypass for the treatment of ischemic stroke.

It is considered controversial whether superficial temporal artery (STA)-middle cerebral artery (MCA) bypass affects the outcome of patients with ischemic stroke. This prospective study was undertaken to demonstrate the effect of STA-MCA bypass on the cerebral blood flow and neurological status of the patients with ischemic stroke. Seventy-five patients underwent unilateral or bilateral STA-MCA bypass surgery. The selection of the patients closely adhered to the criteria of the Japan EC-IC Bypass Trial (JET). Cerebral blood flow (CBF) before and after Diamox administration was measured by single photon emission computed tomography (SPECT) using iodine-123-N-isopropyl-p-iodoamphetamine (IMP). MRI, contrast-enhanced 3D CT scans, and angiography were performed on each patient pre- and postoperatively. Bypass surgery was successfully done in all patients. CBF was significantly increased after STA-MCA bypass (P < 0.05). In addition, reservation of CBF was significantly improved after STA-MCA bypass (P < 0.05). Patients with transient ischemic attack (TIA) did not experience recurrence of such episodes after STA-MCA bypass. The neurological deficit was unchanged in patients with complete stroke after bypass surgery. However, the NIH stroke scale was significantly improved after bypass surgery (P < 0.01). In addition, the satisfaction rate of treatment as assessed by the patients themselves was very high after STA-MCA bypass (>90%) compared to the conservative treatment group (<50%). STA-MCA bypass still plays a limited role in the treatment of ischemic stroke, but may become a bright hope in depressed patients after cerebral ischemia.

Effects of recombinant osteopontin on blood-brain barrier disruption after subarachnoid hemorrhage in rats.

OBJECTS: We determined effects of recombinant OPN (r-OPN), a pleiotropic extracellular matrix protein, on blood-brain barrier (BBB) disruption and matrix metalloproteinase (MMP)-9 activation after subarachnoid hemorrhage (SAH) in rats. METHODS: The endovascular perforation model of SAH was used. SAH or sham-operated rats were treated with pre-SAH intracerebroventricular administration of two dosages of r-OPN, r-OPN+GRGDSP (an L-arginyl-glycyl-L-aspartate-dependent integrin receptor antagonist), albumin or vehicle. Neurological impairments, brain edema and BBB disruption were evaluated, and Western blot analyses were performed in the brain at 24 h after SAH. RESULTS: r-OPN significantly prevented brain edema and BBB disruption compared with the control rats, associated with the suppression of nuclear factor-κB and mitogen-activated protein kinase pathways, leading to MMP-9 inactivation. These effects were blocked by GRGDSP. CONCLUSIONS: L-arginyl-glycyl-L-aspartate-dependent integrin receptor-mediated multiple signaling pathways may be involved in the protective effects of r-OPN against BBB disruption after SAH.