Fumihiro Kawakita

Background: Intravenous administration of clazosentan, a selective endothelin receptor subtype A antagonist, has been used as an anti‐vasospastic agent. This study aimed to investigate whether intrathecal administration of clazosentan prevents neuroinflammation and affects lymphatic clearance of hemoglobin in a mouse model of acute subarachnoid hemorrhage (SAH). Methods: Male C57BL/6 mice (n=109) underwent prechiasmatic cisternal injection models of SAH or sham models. From 30 minutes post‐modeling, mice randomly received a continuous intracerebroventricular infusion of saline or clazosentan (1, 0.2, and 0.04 μg in 192 μL of saline; defined as 50%, 10%, and 2% of the clinically achievable blood concentration, respectively) at a rate of 8 μL/h for 24 hours. The intervention effects were assessed by neurobehavioral testing, SAH grading, and immunohistochemical staining at 24 and 48 hours, and Western blotting at 24 hours post‐modeling. Results: Clazosentan treatment did not influence SAH grading but showed a dose‐dependent trend toward improved survival in SAH mice. A comparison of saline treatment and 50% clazosentan treatment revealed that clazosentan significantly suppressed post‐SAH neurological deterioration, hemoglobin infiltration into the brain, and induction of ionized calcium‐binding adapter molecule 1 and tenascin‐C in the brain, and significantly upregulated vascular endothelial growth factor receptor‐3 in the brain without affecting vascular endothelial growth factor‐C levels. When comparing the effects of different clazosentan doses, an inhibitory effect on neuroinflammation was observed up to 10% clazosentan. At 48 hours post‐modeling, clazosentan administration dose‐dependently inhibited neurological deterioration, hemoglobin infiltration into the brain and activation of perivascular macrophages and microglia, and increased hemoglobin deposition in the deep cervical lymph nodes of SAH mice without intracranial lymphatic vessel proliferation. Conclusions: This study first showed that intrathecal administration of clazosentan can suppress early brain injury in terms of neuroinflammation at cerebrospinal fluid concentrations one‐tenth of the clinically achievable blood concentrations, associated with enhanced lymphatic drainage of hemoglobin.

Objective: Cerebral vasospasm (CVS) following subarachnoid hemorrhage (SAH) is sometimes difficult to treat with conventional balloon angioplasty due to limited device accessibility. We report catheter-based mechanical dilation using a spindle-shaped delivery assist catheter for CVS that is difficult to access with conventional balloon catheters.Case Presentation: A 70-year-old man presented with severe SAH due to a ruptured anterior communicating artery aneurysm and underwent coil embolization along with ventricular drainage. On day 7, CVS of the left M1 segment of the middle cerebral artery (MCA) was treated with balloon angioplasty. On day 9, severe CVS of the left A1 segment of the anterior cerebral artery and the left M2 segment of the MCA was identified. A spindle-shaped delivery assist catheter was advanced to the distal left A1 segment, and mechanical dilation was performed by passing its bulb segment through the stenotic lesion. Subsequent angiography demonstrated vessel dilation. For the CVS in the left M2 segment, balloon angioplasty and selective intra-arterial fasudil hydrochloride infusion were performed. On day 14, newly developed vasospasm in the distal left M2 segment, beyond the segment previously treated with balloon angioplasty, was successfully dilated using the same technique. No procedure-related complications were observed, and no cerebral infarction developed in the treated vascular territories.Conclusion: Catheter-based mechanical dilation using a spindle-shaped delivery assist catheter may be considered as a feasible option for treating CVS when conventional balloon angioplasty is technically difficult. Further experience is required to determine its safety, efficacy, and durability.

Chronic hydrocephalus following aneurysmal subarachnoid hemorrhage (SAH) is a complication that can lead to deterioration in neurological status and cognitive impairment. Our recent clinical study reported that a high concentration of plasma fibulin-5 (FBLN5), a matricellular protein, was associated with the occurrence of chronic hydrocephalus after SAH. This study aimed to investigate whether and how FBLN5 was associated with hydrocephalus during acute to later phases of SAH in mice. C57BL/6 male mice underwent sham or filament perforation SAH modeling, and vehicle or two dosages (0.01 and 0.1 μg) of short or long recombinant FBLN5 (rFBLN5) were randomly administrated by an intracerebroventricular injection. Neurobehavioral tests, measurements of the degree of ventricular enlargement, Western blotting, and immunohistochemical staining were performed to evaluate hydrocephalus 24 and 48 h after SAH. After SAH, ventricular dilatation did not occur at 24 h but developed at 48 h, and both doses of long rFBLN5 with an arginine–glycine–aspartic acid domain suppressed ventricular dilatation at 48 h after SAH. Long rFBLN5 also decreased phosphorylated p38 in the brain parenchyma and prevented post-SAH increases in perivascular macrophages, as well as microglia activation in the brain parenchyma at 48 h after SAH. Although further research is required to clarify the detailed mechanism, this study demonstrated for the first time that exogenous administration of FBLN5 may have a protective effect against ventricular dilatation after experimental SAH.

Background/Objectives: The outcome for aneurysmal subarachnoid hemorrhage (SAH) remains poor, particularly for patients presenting with World Federation of Neurological Surgeons (WFNS) grades IV–V. This study was designed to identify independent prognostic factors in this group of patients with poor-grade SAH. Methods: We prospectively analyzed 357 SAH patients with admission WFNS grades IV–V enrolled in nine primary stroke centers in Mie prefecture, Japan, from 2013 to 2022. This study compared clinical variables, including treatments for angiographic vasospasm and delayed cerebral ischemia (DCI), between patients with favorable (modified Rankin Scale [mRS] scores 0–2) and unfavorable (mRS scores 3–6) outcomes at 90 days post-onset. Multivariate analyses were then performed to identify independent determinants of favorable 90-day outcomes, followed by propensity score matching analyses. Results: The median age was 68 years, and 53.5% of patients had admission WFNS grade V. DCI occurred in 12.9% of patients, and 66.9% had unfavorable outcomes. Independent variables related to unfavorable outcomes were older age, admission WFNS grade V, ventricular drainage, edaravone administration, and delayed cerebral infarction, while those for favorable outcomes were spinal drainage (adjusted odds ratio [aOR] 6.118, 95% confidence interval [CI] 2.687–13.927, p < 0.001), modified Fisher grade 3 (aOR 2.929, 95% CI 1.668–5.143, p < 0.001), and triple prophylactic anti-DCI medication consisting of cilostazol, fasudil hydrochloride and eicosapentaenoic acid (aOR 1.869, 95% CI 1.065–3.279, p = 0.029). Nimodipine is not approved in Japan, and statin and cerebral vasospasm did not influence outcomes. As spinal drainage and the triple prophylactic anti-DCI medication were intervenable variables, propensity score matchings were performed, and they confirmed that both spinal drainage and the triple prophylactic anti-DCI medication were useful to achieve favorable outcomes. Conclusions: In poor-grade SAH, spinal drainage and the triple prophylactic anti-DCI medication may be effective in improving outcomes, possibly by suppressing DCI pathologies other than cerebral vasospasm.

Osteopontin (OPN), a matricellular protein, is produced as a full-length OPN (FL-OPN) and cleaved by thrombin, thus generating the N-terminal half of OPN (OPN N-half) with new functions. Although plasma FL-OPN levels have been associated with neurovascular events after aneurysmal subarachnoid hemorrhage (SAH), plasma OPN N-half levels have never been investigated. In this study, prospective clinical data and plasma samples were collected from 108 consecutive SAH patients with ruptured aneurysms undergoing acute treatment via surgery, and FL-OPN and OPN N-half levels were measured in plasma with a particular focus on delayed cerebral infarction (DCIn), which has the greatest impact on outcomes. Plasma FL-OPN and OPN N-half levels were intercorrelated and significantly higher in patients with DCIn at days 10–12 post-SAH; a greater area under the receiver-operating characteristic curve was observed for OPN N-half levels, with a cut-off value of 70.42 pmol/L. Multivariate analyses revealed that plasma OPN N-half levels of ≥70.42 pmol/L at days 10–12 were independently associated with DCIn development (adjusted odds ratio, 5.65; 95% confidence interval, 1.68–18.97; p = 0.005). Based on the findings of this study and previous reports, an increase in the OPN N-half level may be indicative of a protective mechanism against DCIn development, and, thus, it holds promise as a new therapeutic target against DCIn after aneurysmal SAH.

BACKGROUND: Erythrolysis releases free Hb (hemoglobin), which is one of the most upstream and important molecules causing early brain injury and cerebral vasospasm after subarachnoid hemorrhage (SAH). The purpose of this study was to investigate if a Hb scavenger protein Hp (haptoglobin) supplementation prevents early brain injury and cerebral vasospasm and influences the lymphatic drainage mechanism in an established SAH model of mice by a blood injection into the prechiasmatic cistern. METHODS: This study consisted of 4 parts, with a total of 317 C57BL/6 male mice undergoing sham or SAH modeling, randomly followed by 24-hour intracerebroventricular infusion of no vehicle, 30.1 mg/mL BSA, 30.1 mg/mL Hp (100%; a mixture of Hp1-1, Hp2-1, and Hp2-2), 50% Hp, 25% Hp, and 12.5% Hp solutions from 30 minutes postmodeling. The effects were evaluated at 24 and 48 hours postmodeling. RESULTS: The 100%Hp decreased mortality and brain edema until 48 hours post-SAH and suppressed post-SAH neurological impairments, Hb infiltrations into the perivascular spaces and brain tissues, fibrinogen-positive microthrombi formation, microglial activation, and caspase-dependent neuronal apoptosis, as well as large-vessel vasospasm on India-ink angiography at 24 hours compared with vehicle-treated SAH mice. The Hp solutions up to 50% concentrations also prevented post-SAH neurological impairments, and those up to 25% concentrations suppressed post-SAH neuronal apoptosis and vasospasm development until 48 hours. Immunohistochemical staining of deep cervical and mandibular lymph nodes demonstrated that Hb was increased in the lymphatic sinus after SAH and was further increased by Hp administration in SAH animals. CONCLUSIONS: This study first showed that an Hp concentrate prevented early brain injury and cerebral vasospasm by inhibiting Hb penetration into brain tissues and increasing lymphatic drainage of free Hb in an established SAH model of mice.

Aneurysmal subarachnoid hemorrhage (SAH) has increased with the aging of the population, but the outcome for elderly SAH patients is very poor. Therefore, predicting the outcome is important for determining whether to pursue aggressive treatment. Pigment epithelium-derived factor (PEDF) is a matricellular protein that is induced in the brain, and the plasma levels could be used as a biomarker for the severity of metabolic diseases. This study investigated whether acute-phase plasma PEDF levels could predict outcomes after aneurysmal SAH in the elderly. Plasma samples and clinical variables were collected over 1–3 days, post-SAH, from 56 consecutive elderly SAH patients ≥75 years of age registered in nine regional stroke centers in Japan between September 2013 and December 2016. The samples and variables were analyzed in terms of 3-month outcomes. Acute-phase plasma PEDF levels were significantly elevated in patients with ultimately poor outcomes, and the cutoff value of 12.6 µg/mL differentiated 3-month outcomes with high sensitivity (75.6%) and specificity (80.0%). Acute-phase plasma PEDF levels of ≥12.6 µg/mL were an independent and possibly better predictor of poor outcome than previously reported clinical variables. Acute-phase plasma PEDF levels may serve as the first biomarker to predict 3-month outcomes and to select elderly SAH patients who should be actively treated.