Transplanted human iPSC-derived vascular endothelial cells promote functional recovery by recruitment of regulatory T cells to ischemic white matter in the brain.

BACKGROUND: Ischemic stroke in white matter of the brain induces not only demyelination, but also neuroinflammation. Peripheral T lymphocytes, especially regulatory T cells (Tregs), are known to infiltrate into ischemic brain and play a crucial role in modulation of inflammatory response there. We previously reported that transplantation of vascular endothelial cells generated from human induced pluripotent stem cells (iVECs) ameliorated white matter infarct. The aim of this study is to investigate contribution of the immune system, especially Tregs, to the mechanism whereby iVEC transplantation ameliorates white matter infarct. METHODS: iVECs and human Tregs were transplanted into the site of white matter lesion seven days after induction of ischemia. The egress of T lymphocytes from lymph nodes was sequestered by treating the animals with fingolimod (FTY720). The infarct size was evaluated by magnetic resonance imaging. Immunohistochemistry was performed to detect the activated microglia and macrophages, T cells, Tregs, and oligodendrocyte lineage cells. Remyelination was examined by Luxol fast blue staining. RESULTS: iVEC transplantation reduced ED-1+ inflammatory cells and CD4+ T cells, while increased Tregs in the white matter infarct. Treatment of the animals with FTY720 suppressed neuroinflammation and reduced the number of both CD4+ T cells and Tregs in the lesion, suggesting the importance of infiltration of these peripheral immune cells into the lesion in aggravation of neuroinflammation. Suppression of neuroinflammation by FTY720 per se, however, did not promote remyelination in the infarct. FTY720 treatment negated the increase in the number of Tregs by iVEC transplantation in the infarct, and attenuated remyelination promoted by transplanted iVECs, while it did not affect the number of oligodendrocyte lineage cells increased by iVEC transplantation. Transplantation of Tregs together with iVECs into FTY720-treated ischemic white matter did not affect the number of oligodendrocyte lineage cells, while it remarkably promoted myelin regeneration. CONCLUSIONS: iVEC transplantation suppresses neuroinflammation, but suppression of neuroinflammation per se does not promote remyelination. Recruitment of Tregs by transplanted iVECs contributes significantly to promotion of remyelination in the injured white matter.

Impact of craniotomy area on improvement of cerebral blood flow in combined revascularization surgery for moyamoya disease.

OBJECTIVE: To investigate factors associated with improvements in cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) after combined revascularization surgery for moyamoya disease, with special attention to the size of craniotomy. METHODS: We retrospectively analyzed 35 hemispheres in 27 patients with adult and older pediatric moyamoya disease. CBF and CVR were measured separately in the MCA and ACA territories from acetazolamide-challenged single-photon emission computed tomography before and after 6 months postoperatively, and associations with various factors were analyzed. RESULTS: Postoperative CBF improved in patients with lower preoperative blood flow in both ACA and MCA territories. Postoperative CVR improved in 32 of 35 patients (91.4%) in the MCA territory and in 30 of 35 patients (85.7%) in the ACA territory, with more prominent improvement in the MCA territory than in the ACA territory (MCA territory 29.7% vs ACA territory 21.1%, p = 0.015). Craniotomy area did not correlate with postoperative CBF and only MCA territory was associated with good (≥30%) CVR improvement (odds ratio 9.33, 95% confidence interval 1.91-45.6, p = 0.003). CONCLUSIONS: Postoperative CBF improved in adult and older pediatric cases, reflecting preoperative CBF. Postoperative CVR improved in most cases, although the degree of improvement was more prominent in the MCA territory than in the ACA territory, suggesting a contribution of the temporal muscle. Large craniotomy area was not associated with improved blood flow in the ACA territory and should be applied prudently.

Usefulness of dual isotope 123I-IMP and 201Tl SPECT for the diagnosis of primary central nervous system lymphoma and glioblastoma.

BACKGROUND: Preoperative differential diagnosis between primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM) is important because these tumors require different surgical strategies. This study investigated the usefulness of dual isotope, iodine-123-labeled N-isopropyl-p-iodo-amphetamine (123I-IMP) and thallium-201 chloride single-photon emission computed tomography (201Tl SPECT) for the differential diagnosis. METHODS: Twenty-five PCNSL patients and 27 GBM patients who underwent dual isotope imaging, 123I-IMP and 201Tl SPECT, are included. Tumor-to-normal (T/N) ratio was calculated from the ratio of maximum tracer counts in the lesion to the mean counts in the contralateral cerebral cortex. The mean and minimum apparent diffusion coefficient values (ADCmean and ADCmin, respectively) on magnetic resonance imaging were also analyzed. RESULTS: Delayed phase 123I-IMP SPECT was the most useful imaging examination for the differentiation between PCNSL and GBM compared with early phase 123I-IMP SPECT, early and delayed phase 201Tl SPECT, ADCmean, and ADCmin. However, the median T/N ratios of PCNSL and GBM were 1.32 and 0.83, respectively, in the delayed phase 123I-IMP SPECT. On the other hand, the median T/N ratios of PCNSL and GBM were 3.10 and 2.34, respectively, in the delayed phase 201Tl SPECT, with excellent tumor detection. CONCLUSION: Delayed phase 123I-IMP SPECT could differentiate between PCNSL and GBM with high accuracy, but T/N ratio was low and tumor detection was poor. 201Tl SPECT was useful for estimation of the malignancy and localization of the tumors with high T/N ratio. Dual isotope 123I-IMP and 201Tl SPECT was useful for the preoperative diagnosis of PCNSL and GBM.

Autonomic dysreflexia associated with cervical spinal cord gliofibroma: case report.

BACKGROUND: Autonomic dysreflexia (AD) is an abnormal reflex of the autonomic nervous system normally observed in patients with spinal cord injury from the sixth thoracic vertebra and above. AD causes various symptoms including paroxysmal hypertension due to stimulus. Here, we report a case of recurrent AD associated with cervical spinal cord tumor. CASE PRESENTATION: The patient was a 57-year-old man. Magnetic resonance imaging revealed an intramedullary lesion in the C2, C6, and high Th12 levels. During the course of treatment, sudden loss of consciousness occurred together with abnormal paroxysmal hypertension, marked facial sweating, left upward conjugate gaze deviation, ankylosis of both upper and lower extremities, and mydriasis. Seizures repeatedly occurred, with symptoms disappearing after approximately 30 min. AD associated with cervical spinal cord tumor was diagnosed. Histological examination by tumor biopsy confirmed the diagnosis of gliofibroma. Radiotherapy was performed targeting the entire brain and spinal cord. The patient died approximately 3 months after treatment was started. CONCLUSIONS: AD is rarely associated with spinal cord tumor, and this is the first case associated with cervical spinal cord gliofibroma. AD is important to recognize, since immediate and appropriate response is required.

Thalamic anterior part of the ventral posterolateral nucleus and central lateral nucleus in the genesis of central post-stroke pain.

BACKGROUND: The genesis of central post-stroke pain (CPSP) is important but difficult to understand. We evaluated the involvement of the thalamic anterior part of the ventral posterolateral nucleus (VPLa) and central lateral nucleus (CL) in the occurrence of CPSP. METHOD: Stereotactic thalamotomy was performed on the posterior part of the ventral lateral nucleus (VLp)-VPLa and CL in 9 patients with CPSP caused by deep-seated intracerebral hemorrhage. Computed tomography (CT) did not reveal definite thalamic lesion in 5 patients but did in 4 patients. Electrophysiological studies of these thalamic nuclei were carried out during the surgery. Anatomical studies using CT were performed in another 20 patients with thalamic hemorrhage who had clear consciousness but had sensory disturbance at onset. RESULTS: Neural activities were preserved and hyperactive and unstable discharges (HUDs) were often recognized along the trajectory in the thalamic VLp-VPLa in 5 patients without thalamic lesion. Surgical modification of this area ameliorated pain, particularly movement-related pain. Neural activities were hypoactive in the other 4 patients with thalamic lesion. However, neural activities were preserved and HUDs were sometimes recognized in the CL. Sensory responses were seen, but at low rate, in the sensory thalamus. Anatomical study showed that the thalamic lesion was obviously smaller in the patients with developing pain in the chronic stage. CONCLUSIONS: Change in neural activities around the cerebrovascular disease lesion in the thalamic VPLa or CL might affect the perception of sensory impulses or sensory processing in those thalamic nuclei, resulting in the genesis of CPSP.

Electrical Thalamic Stimulation in the Anterior Part of the Ventral Posterolateral Nucleus for the Treatment of Patients With Central Poststroke Pain.

OBJECTIVES: The effects of thalamic stimulation of the anterior part of the ventral posterolateral nucleus (VPLa) for central poststroke pain (CPSP) and the pain-related electrophysiological characteristics of this structure were investigated. MATERIALS AND METHODS: Nine patients with CPSP manifesting as hemibody pain were enrolled. Stereotactic thalamic VPLa stimulation was implemented, and intraoperative electrophysiological studies on hyperactive and unstable discharges (HUDs) and responses to sensory and electrical stimulation were performed in the sensory thalamus. A preoperative somatosensory-evoked potential (SEP) study was carried out in all nine patients and in eight other patients with localized pain. RESULTS: The patients were classified into two groups: a HUD-dominant group (group H, n = 5) and a sensory response-dominant group (group R, n = 4). HUDs were frequently encountered in the thalamic VPLa in the former group. The total number of HUDs and the number along the trajectory to the VPLa in group H were significantly larger than those in group R. The improvements on the pain numeric rating scale in group H were significantly higher than those in group R two years after surgery. The amplitude ratio of the SEP N20s in the ipsilateral to the contralateral side of CVD lesion in the study group was significantly lower than in the localized pain group. CONCLUSIONS: Adequate and stable pain relief with thalamic VPLa stimulation is obtainable in patients with CPSP who exhibit hyperactivity and electrical instability along the trajectory to this nucleus. Both responders and nonresponders were found to have severe dysfunction of the lemniscal system.

Acute Endovascular Revascularization for Patients with Common Carotid Artery Occlusion Apparent on Cervical Magnetic Resonance Angiography.

OBJECTIVES: In the endovascular treatment of acute cerebral large-vessel occlusion, cervical magnetic resonance angiography (MRA) is a useful modality for assessing the access route. However, we sometimes encounter cases in which not only the internal carotid artery (ICA), but also the common carotid artery (CCA) is poorly visualized, leading to hesitation over which devices and techniques to choose for revascularization. We retrospectively evaluated such cases, focusing on image findings and treatment results. MATERIALS AND METHODS: Data from 96 patients who underwent acute endovascular revascularization from January 2016 to December 2019 were analyzed. We extracted patients with poor CCA visualization on cervical MRA from 35 cases with ICA occlusion, and examined angiographic findings, treatment methods, and outcomes. RESULTS: Poor visualization of the CCA in cervical MRA was observed in 8 cases. All cases displayed atrial fibrillation or sick sinus syndrome. Angiographic findings showed true CCA occlusion in 2 patients and ICA occlusion in 6 patients. Reasons for the inability to visualize the CCA on cervical MRA were speculated to be stenosis of the external carotid artery (ECA), presence of embolism in the ECA, or severe heart failure. In cases of true CCA occlusion, thrombus was aspirated using the balloon guide catheter and good recanalization was obtained. Seven of 8 patients displayed favorable recanalization, with good prognosis after 90 days in 5 patients. CONCLUSIONS: Poor CCA visualization on cervical MRA does not necessarily represent true CCA occlusion. Aspiration of thrombus from a balloon guide catheter is effective for true CCA occlusion.

Transplantation of iPS-derived vascular endothelial cells improves white matter ischemic damage.

White matter infarct induces demyelination and brain dysfunction. We previously reported that transplantation of brain microvascular endothelial cells improved the behavioral outcome and promoted remyelination by increasing the number of oligodendrocyte precursor cells in the rat model of white matter infarct. In this study, we investigated the effects of transplantation of vascular endothelial cells generated from human induced pluripotent stem cells (iPSCs) on the rat model of white matter infarct. Seven days after induction of ischemic demyelinating lesion by injection of endothelin-1 into the internal capsule of a rat brain, iPSC-derived vascular endothelial cells (iVECs) were transplanted into the site of demyelination. The majority of iVECs transplanted into the internal capsule survived for 14 days after transplantation when traced by immunohistochemistry for a human cytoplasmic protein. iVEC transplantation significantly recovered hind limb rotation angle as compared to human iPSC or rat meningeal cell transplantation when evaluated using footprint test. Fourteen days after iVEC transplantation, the infarct area remarkably decreased as compared to that just before the transplantation when evaluated using magnetic resonance imaging or luxol fast blue staining, and remyelination was promoted dramatically in the infarct when assessed using luxol fast blue staining. Transplantation of iVECs increased the number of oligodendrocyte lineage cells and suppressed the inflammatory response and reactive astrocytogenesis. These results suggest that iVEC transplantation may prove useful in treatment for white matter infarct.

Computed tomography findings after head injury preceding chronic subdural hematoma.

OBJECTIVE: Head CT is sometimes performed immediately after minor head injury; however, which cases develop into chronic subdural hematoma (CSDH) remains unclear. Here, the authors retrospectively reviewed the rare cases of CSDH treated surgically in which early head CT had been performed after the initial head trauma. METHODS: A total of 172 patients (133 male and 39 female, median age 76 years) underwent surgery for CSDH at Gunma University Hospital between April 2010 and December 2017. Among these patients were 23 who had visited Gunma University Hospital or a nearby hospital and had undergone head CT within 7 days after the initial head trauma. Characteristics of the initial head CT were examined to identify indicators of subsequent CSDH. RESULTS: Among the 23 CSDH cases (17 male and 6 female, median age 80 years), CT scans were obtained on the day of the initial injury (day 0) in 19 cases (25 sides) and 1-7 days after injury in 12 cases (19 sides); scans were obtained during both periods in 8 cases (12 sides), so that a total of 44 sides were examined. These CT scans were divided into two groups according to when they were obtained; cases in which scans were taken during both periods were included in both groups. Head CT performed on the day of injury showed normal findings in 5 (20%) of 25 sides, thin subdural effusion (SDE) ≤ 6 mm in 16 (64%) of 25 sides, thick SDE > 6 mm in 3 (12%) of 25 sides, and acute subdural hematoma (ASDH) in 1 (4%) of 25 sides. CT from 1-7 days after trauma showed thick SDE in 9 (47%) of 19 sides, thin SDE in 8 (42%) of 19 sides, and ASDH in 2 (11%) of 19 sides. A high-density line in the lateral direction (onion skin-like) was found between the skull and the brain in 9 (35%) of 26 sides with SDE on initial CT 0-7 days after the injury. CONCLUSIONS: ASDH was not a common cause of CSDH. Head CT at the time of trauma that precedes CSDH often showed SDE. Such SDE that precedes CSDH was often close to the detection limit of CT immediately after the injury but became more apparent from the day after the injury.

Extended endoscopic endonasal resection of craniopharyngioma using intraoperative visual evoked potential monitoring: technical note.

BACKGROUND: To avoid deterioration of visual function, extended endoscopic endonasal transsphenoidal surgery (TSS) for craniopharyngioma was performed with visual evoked potential (VEP) monitoring using light-emitting diodes (LEDs). METHODS: The position of the optic chiasm was carefully evaluated on the preoperative midsagittal magnetic resonance (MR) images. Intraoperatively, direct and sharp dissection of the tumor from the optic chiasm was performed under VEP monitoring with LEDs through extended endoscopic endonasal TSS. If the VEP finding changed and became unstable, the operator were informed and stopped the surgical manipulation for the optic chiasm to recover. After 5-10 min, recovery of VEP findings was checked and the procedure resumed. RESULTS: Extended endoscopic endonasal TSS with VEP monitoring was performed in consecutive 7 adult patients with newly diagnosed suprasellar craniopharyngiomas with maximum diameters of 25-41 mm (mean 33.7 mm). VEPs were stable throughout the surgery in 5 cases, but showed temporary instability and amplitude decrease in 2 cases, although the VEPs had recovered at the end of the surgery. Visual function, evaluated using visual impairment score, was improved after surgery in all patients. Gross total removal was achieved in 5 cases, and subtotal removal (90%) in 2 cases. CONCLUSIONS: Intraoperative VEP monitoring is the only way to test visual function during surgery, and may be important and helpful in extended endoscopic endonasal TSS, which requires direct dissection between the optic nerve and craniopharyngioma under the endoscope.

Combined supra-infrasellar approach to pituitary macroadenoma with oculomotor cistern extension: surgical strategy and experience.

BACKGROUND: Oculomotor cistern extension (OMCE) of pituitary adenoma through the oculomotor triangle may be one of the major characteristics of multi-lobulated adenoma. The OMCE may be hard to remove only through the endonasal approach. METHOD: We applied the simultaneous combined supra-infrasellar approach to remove pituitary adenoma with relatively large OMCE. Four (7.3%) of 55 consecutive patients with initially operated pituitary macroadenoma (> 10 mm) had OMCE. The combined supra-infrasellar approach was adopted in two cases with relatively large OMCE. RESULTS: The simultaneous combined supra-infrasellar approach was performed with the transcranial microscopic transsylvian anterior temporal approach and the nasal endoscopic approach. The medial main mass was removed through the nasal side. The lateral OMCE was also removed through the nasal side by pushing the tumor in the sellar direction from the transcranial side. The oculomotor nerve was confirmed with electrical nerve stimulation. The main medial mass and the OMCE were mostly removed in both cases. Remnant tumor in the cavernous sinus was treated by gamma knife radiosurgery. Endoscopic transsphenoidal removal was performed in the other two cases with relatively small OMCE. CONCLUSIONS: Pituitary macroadenomas with OMCE are a newly recognized form of progression with important implications for surgical strategy. The combined supra-infrasellar approach performed with the transcranial microscopic transsylvian anterior temporal approach using electrical nerve stimulation and the nasal endoscopic approach may be useful for this type of multi-lobulated pituitary adenoma.

Angiographical Jaggy Sign of Remnant M2 Occlusion during Acute Mechanical Thrombectomy.

BACKGROUND AND PURPOSE: During mechanical thrombectomy for acute main trunk occlusion, we sometimes encounter difficult situation; 1 M2 branch of the middle cerebral artery is successfully recanalized, while the other remains occluded. In this study, we focused on the angiographical findings of remnant occlusion. METHODS: Among 83 patients who underwent mechanical thrombectomy for the acute internal carotid artery or proximal middle cerebral artery (M1) occlusion, 25 patients (30%) intraoperatively exhibited the remnant M2 occlusion, in spite of the recanalization of the other M2. We classified the angiographical findings of the remnant M2 occlusion and examined the clinical features, prognosis, and complications, in relation to additional thrombectomy. RESULTS: The remnant M2 occlusion was classified into stump type (40%, 10 cases), round deficit type (28%, 7 cases), and jaggy type (32%, 8 cases). Multivariate analysis suggested that noncardioembolic stroke may lead to jaggy type remnant occlusion with marginal significance (P = .051). Additional thrombectomy for the remnant M2 occlusion resulted in failed recanalization in 6% in the nonjaggy (stump or round deficit) type, whereas in 50% in the jaggy type groups (P = .023). Symptomatic intracranial hemorrhage occurred in 6% in the nonjaggy and 38% in the jaggy groups (P = .081), and poor outcome at discharge in 29% and in 50%, respectively. CONCLUSIONS: Angiographical jaggy sign in the remnant M2 occlusion suggests the pre-existing or procedure-related pathology, such as atherosclerosis, vasospasm, or arterial dissection. Additional thrombectomy should be carefully determined, as which might lead to adverse events and poor outcomes.

Cerebellar high-grade astrocytoma with IDH mutations in the elderly: A report of two cases.

Cerebellar high-grade gliomas are rare, and likely to affect younger patients compared with those of cerebral origin. Recent genetic analyses have revealed that isocitrate dehydrogenase (IDH) 1/2 mutations are rare in infratentorial gliomas. In this paper, we report two elderly cases of IDH-mutated cerebellar high-grade glioma with unusual histological features and uncommon patient ages. One case was an 83-year-old man, whose tumor was predominantly composed of densely packed round-to-polygonal epithelioid cells. The other was a 75-year-old woman's high-grade astrocytoma characterized by cord-like structures and the perivascular papillary arrangements with varying amounts of myxoid matrix. The former harbored IDH1 R132H mutation, whereas the latter had IDH2 R172K mutation. According to our literature review, eight cases of IDH-mutated infratentorial gliomas including the present cases have been reported, and four had mutations other than IDH1 R132H. Moreover, we herein report the first elderly case of IDH2-mutation. Although the number is limited, IDH-mutant infratentorial diffuse gliomas may have clinical, histological and genetic features different from supratentorial cases.

Anaplastic ganglioglioma with epithelioid cell components.

A 40-year-old man was admitted to our hospital because of disorientation and mild left-sided weakness. Radiological examination revealed a solid and cystic tumor in the right temporal lobe, and total resection was performed. Histologically, the tumor was composed mainly of low-grade gangiloglioma and had some high-grade glial components with focal necrosis and microvascular proliferations. In the high-grade component, there were epithelioid cells with round cytoplasm and eccentric nuclei. The high-grade area with epithelioid cells was intermingled within the low-grade area, which suggests that epithelioid cells were an anaplastic transformation of ganglioglioma. The epithelioid cells were histologically similar to neoplastic cells of epithelioid glioblastoma (E-GBM), a rare aggressive variant of isocitric dehydrogenase wild-type glioblastoma. A BRAF V600E mutation, frequently observed in E-GBM, was detected in both the ganglioglioma and epithelioid cell components. The epithelioid cells were mitotically active, which suggests that if the surgery was delayed, the histological appearance might have eventually evolved into E-GBM. Indeed, a case of pleomorphic xanthoastrocytoma which transformed into E-GBM after a long latency was reported elsewhere. This is the first report to describe focal epithelioid cells in anaplastic ganglioglioma.

Systemic metabolism and energy consumption after microsurgical clipping and endovascular coiling for aneurysmal subarachnoid hemorrhage.

BACKGROUND: The postoperative metabolic states of subarachnoid hemorrhage (SAH) patients were investigated using indirect calorimetry (IDC) and various nutritional evaluations to establish any difference in perioperative metabolic and nutritional states between microsurgical and endovascular treatment. METHODS: This study included 30 acute aneurysmal SAH patients with ruptured intracranial aneurysms treated by surgical clipping (n = 16) or coil embolization (n = 14) at a single institute. The resting energy expenditure (REE) and respiratory quotient were measured using IDC on days 1, 4, 7, 10, 14, and 17-21 after the operation. Various blood tests, including C-reactive protein (CRP) and prealbumin, were evaluated on the same days. RESULTS: The clipping group showed a significant increase in REE/basal energy expenditure (BEE) compared with the coiling group on days 1 and 4 (p = 0.04 and 0.03, respectively). No significant differences were found on days 7, 10, 14, and 17-21. The mean REE/BEE on days 1-14 and 1-21 showed no significant differences between the groups with repeated measures analysis of variance. The clipping group showed a significant decrease of prealbumin on day 4 and significant increase in CRP on days 1, 4, and 7. CONCLUSIONS: The clipping group was in the hypermetabolic state compared with the coiling group during the very early postoperative period. However, the difference associated with the treatment modality was relatively small compared to the effects of the SAH and of the sequelae.

Lipoxygenase-mediated generation of lipid peroxides enhances ferroptosis induced by erastin and RSL3.

In cancer cells the small compounds erastin and RSL3 promote a novel type of cell death called ferroptosis, which requires iron-dependent accumulation of lipid reactive oxygen species. Here we assessed the contribution of lipid peroxidation activity of lipoxygenases (LOX) to ferroptosis in oncogenic Ras-expressing cancer cells. Several 12/15-LOX inhibitors prevented cell death induced by erastin and RSL3. Furthermore, siRNA-mediated silencing of ALOX15 significantly decreased both erastin-induced and RSL3-induced ferroptotic cell death, whereas exogenous overexpression of ALOX15 enhanced the effect of these compounds. Immunofluorescence analyses revealed that the ALOX15 protein consistently localizes to cell membrane during the course of ferroptosis. Importantly, treatments of cells with ALOX15-activating compounds accelerated cell death at low, but not high doses of erastin and RSL3. These observations suggest that tumor ferroptosis is promoted by LOX-catalyzed lipid hydroperoxide generation in cellular membranes.

Fibronectin on extracellular vesicles from microvascular endothelial cells is involved in the vesicle uptake into oligodendrocyte precursor cells.

We previously reported transplantation of brain microvascular endothelial cells (MVECs) into cerebral white matter infarction model improved the animal's behavioral outcome by increasing the number of oligodendrocyte precursor cells (OPCs). We also revealed extracellular vesicles (EVs) derived from MVECs promoted survival and proliferation of OPCs in vitro. In this study, we investigated the mechanism how EVs derived from MVECs contribute to OPC survival and proliferation. Protein mass spectrometry and enzyme-linked immunosorbent assay revealed fibronectin was abundant on the surface of EVs from MVECs. As fibronectin has been reported to promote OPC survival and proliferation via integrin signaling pathway, we blocked the binding between fibronectin and integrins using RGD sequence mimics. Blocking the binding, however, did not attenuate the survival and proliferation promoting effect of EVs on OPCs. Flow cytometric and imaging analyses revealed fibronectin on EVs mediates their internalization into OPCs by its binding to heparan sulfate proteoglycan on OPCs. OPC survival and proliferation promoted by EVs were attenuated by blocking the internalization of EVs into OPCs. These lines of evidence suggest that fibronectin on EVs mediates their internalization into OPCs, and the cargo of EVs promotes survival and proliferation of OPCs, independent of integrin signaling pathway.

An essential role for functional lysosomes in ferroptosis of cancer cells.

Pharmacological challenges to oncogenic Ras-expressing cancer cells have shown a novel type of cell death, ferroptosis, which requires intracellular iron. In the present study, we assessed ferroptosis following treatment of human fibrosarcoma HT1080 cells with several inhibitors of lysosomal activity and found that they prevented cell death induced by the ferroptosis-inducing compounds erastin and RSL3. Fluorescent analyses with a reactive oxygen species (ROS) sensor revealed constitutive generation of ROS in lysosomes, and treatment with lysosome inhibitors decreased both lysosomal ROS and a ferroptotic cell-death-associated ROS burst. These inhibitors partially prevented intracellular iron provision by attenuating intracellular transport of transferrin or autophagic degradation of ferritin. Furthermore, analyses with a fluorescent sensor that detects oxidative changes in cell membranes revealed that formation of lipid ROS in perinuclear compartments probably represented an early event in ferroptosis. These results suggest that lysosomal activity is involved in lipid ROS-mediated ferroptotic cell death through regulation of cellular iron equilibria and ROS generation.

A case of high-grade astrocytoma with BRAF and ATRX mutations following a long-standing course over two decades.

Pediatric high-grade gliomas are rare and occasionally hard to classify. These tumors often feature a well-demarcated histology and are expected to have a better outcome than ordinary diffuse high-grade gliomas in adults. We herein report a case of circumscribed high-grade glioma that showed a distinct molecular profile and followed an excellent course for 26 years. The patient, a 3-year-old boy at onset, presented with a contrast-enhancing mass in the right temporal lobe and underwent resection. Histologically, the tumor mainly consisted of compact bundles of GFAP-positive spindle cells. With its malignant features including brisk mitotic activity and pseudopallisading necrosis, a diagnosis of high-grade astrocytoma was made and adjuvant chemoradiotherapy was administered. After a disease-free period of two decades, the tumor recurred locally. The resected tumor was histologically identical to the primary tumor and additionally contained pleomorphic cells, but lacked eosinophilic granular bodies and reticulin networks. The primary and recurrent tumors both harbored the BRAF V600E mutation, and the recurrent tumor was immunonegative for ATRX. Combined BRAF and ATRX mutations are rare in gliomas, with only a pediatric case of glioblastoma being reported in the literature. However, our case cannot be regarded as glioblastoma because of its well-demarcated histology and excellent course. The distinction of either a diffuse or localized nature in gliomas is important, particularly in children, for predicting prognoses and selecting adjuvant therapies that consequently affect life-long health care. The present case provides novel insights into pediatric high-grade astrocytomas.

Sex- and Age-Related Differences in the Clinical and Neuroimaging Characteristics of Patients With Spontaneous Intracranial Hypotension: A Records Review.

BACKGROUND: The significance of sex- and age-related differences in the clinical course of spontaneous intracranial hypotension (SIH) was investigated. METHODS: We retrospectively studied 40 consecutive patients (female:male = 28:12, median age 41.5 years) treated under clinical diagnoses of SIH satisfying the International Classification of Headache Disorders 3rd edition criteria, including 37 patients (92.5%) with diffuse pachymeningeal enhancement. The patients were divided into two groups by age and sex, and the clinical and neuroimaging findings in each group were investigated. RESULTS: Acute onset (female:male = 82.1%:50.0%, P = .042), severe headache (75.0%:41.7%, P = .045) occurred with higher frequency in females than in males, and SDH occurred with lower frequency in females than in males (28.6%:75.0%, P = .006). Duration until the consultation (2:14 days, P = .022), SDH thickness (0:7.1 mm, P = .001), and iter displacement (1.6:7.1 mm, P = .004) was greater in males. Acute onset (Younger [≤40 years]: older [>40 years] = 94.1%:56.5%, P = .012), occurred with higher frequency in younger patients, and duration until the consultation (1:5 days, P = .001), frequency of SDH (17.7%:60.9%, P = .010), SDH thickness (0:5.9 mm, P = .003), in older patients. All nine patients with thunderclap headache were female, with median age of 37 years. CONCLUSIONS: More severe clinical symptoms with acute onset were observed in females and younger patients of SIH. Comparatively rare subdural hygroma/hematoma on magnetic resonance imaging might result from the shorter duration to diagnosis in females and younger patients. KEY WORDS: spontaneous intracranial hypotension, sex, age, magnetic resonance imaging, thunderclap headache.