Ischemic stroke is a critical disease caused by cerebral artery occlusion in the central nervous system (CNS). Recent therapeutic advances, such as neuroendovascular intervention and thrombolytic therapy, have allowed recanalization of occluded brain arteries in an increasing number of stroke patients. Although previous studies have focused on rescuing neural cells that still survive despite decreased blood flow, expanding the therapeutic time window may allow more patients to undergo reperfusion in the near future, even after lethal ischemia, which is characterized by death of mature neural cells, such as neurons and glia. However, it remains unclear whether early reperfusion following lethal ischemia results in positive outcomes. The present study used two ischemic mouse models—90-min transient middle cerebral artery occlusion (t-MCAO) paired with reperfusion to induce lethal ischemia and permanent middle cerebral artery occlusion (p-MCAO)—to investigate the effect of early reperfusion up to 8 w following MCAO. Although early reperfusion following 90-min t-MCAO did not rescue mature neural cells, it preserved the vascular cells within the ischemic areas at 1 d following 90-min t-MCAO compared to that following p-MCAO. In addition, early reperfusion facilitated the healing processes, including not only vascular but also neural repair, during acute and chronic periods and improved recovery. Furthermore, compared with p-MCAO, early reperfusion after t-MCAO prevented behavioral symptoms of neurological deficits without increasing negative complications, including hemorrhagic transformation and mortality. These results indicate that early reperfusion provides beneficial effects presumably via cytoprotective and regenerative mechanisms in the CNS, suggesting that it may be useful for stroke patients that experienced lethal ischemia.

Demyelination and remyelination play pivotal roles in the pathological process of multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE), a well-established animal model of MS. Although increasing evidence shows that various stimuli can promote the activation/induction of endogenous neural stem/progenitor cells (NSPCs) in the central nervous system, the potential contributions of these cells to remyelination following inflammatory injury remain to be fully investigated. In the present study, using an adult mouse model of EAE induced by myelin oligodendrocyte glycoprotein (MOG) peptide, we investigated whether adult NSPCs in the spinal cord can lead to remyelination under inflammatory conditions. Immunohistochemistry showed that cells expressing the NSPC marker Nestin appeared after MOG peptide administration, predominantly at the sites of demyelination where abundant inflammatory cells had accumulated, whereas Nestin⁺ cells were rarely present in the spinal cord of PBS-treated control mice. In vitro, Nestin⁺ NSPCs obtained from EAE mice spinal cords could differentiate into multiple neural lineages, including neurons, astrocytes, and myelin-producing oligodendrocytes. Using the Cre–LoxP system, we established a mouse strain expressing yellow fluorescent protein (YFP) under the control of the Nestin promoter and investigated the expression patterns of YFP-expressing cells in the spinal cord after EAE induction. At the chronic phase of the disease, immunohistochemistry showed that YFP⁺ cells in the injured regions expressed markers for various neural lineages, including myelin-forming oligodendrocytes. These results show that adult endogenous NSPCs in the spinal cord can be subject to remyelination under inflammatory conditions, such as after EAE, suggesting that endogenous NSPCs represent a therapeutic target for MS treatment.

Primary malignant melanoma of the vagina is extremely rare, with a poorer prognosis than cutaneous malignant melanoma. Previous studies have explored the repurposing of itraconazole, a common oral anti-fungal agent, for the treatment of various cancers. Here, we describe a patient with metastatic, unresectable vaginal malignant melanoma treated with 200 mg oral itraconazole twice a day in a clinical window-of-opportunity trial. A 64-year-old Japanese woman with vaginal and inguinal tumours was referred to our institution. On the basis of an initial diagnosis of vaginal cancer metastatic to the inguinal lymph nodes, we treated her with itraconazole in a clinical trial until the biopsy and imaging study results were obtained. During this period, biopsies were performed three times, and 18F-fluoro-deoxyglucose positron emission tomography (FDG/PET)–computed tomography (CT) was performed twice. Biopsy results confirmed the diagnosis of primary malignant melanoma of the vagina. Imaging studies revealed metastases to multiple sites, including the brain, for which she underwent gamma-knife radiosurgery. During the window period before nivolumab initiation, the patient received itraconazole for 30 days. Within a week of itraconazole initiation, pain in the inguinal nodes was ameliorated. PET–CT on days 6 and 30 showed a reduction in tumour size and FDG uptake, respectively. The biopsied specimens obtained on days 1, 13, and 30 were subjected to cDNA microarray analysis, which revealed a 100-fold downregulation in the transcription of four genes: STATH, EEF1A2, TTR, and CDH2. After 12 weeks of nivolumab administration, she developed progressive disease and grade 3 immune-related hepatitis. Discontinuation of nivolumab resulted in the occurrence of left pelvic and inguinal pain. Following re-challenge with itraconazole, the patient has not reported any pain for 4 months. The findings of this case suggest that itraconazole is a potential effective treatment option for primary malignant melanoma of the vagina. Moreover, we identified potential itraconazole target genes, which could help elucidate the mechanism underlying this disease and potentially aid in the development of new therapeutic agents.

Epithelioid glioblastoma (E‐GBM) was recently designated as a subtype of glioblastoma (GBM) by the World Health Organization (2016). E‐GBM is an aggressive and rare variant of GBM that primarily occurs in children and young adults. Although most characterized cases of E‐GBM harbor a mutation of the BRAF gene in which valine (V) is substituted by glutamic acid (E) at amino acid 600 (BRAF‐V600E), in addition to telomerase reverse transcriptase promoter mutations and homozygous CDKN2A/B deletions, the origins and cellular nature of E‐GBM remain uncertain. Here, we present a case of E‐GBM that exhibits antigenic and functional traits suggestive of microglia. Although no epithelial [e.g., CKAE1/3, epithelial membrane antigen (EMA)] or glial (e.g., GFAP, Olig2) markers were detected by immunohistochemical staining, the microglial markers CD68 and Iba1 were readily apparent. Furthermore, isolated E‐GBM‐derived tumor cells expressed microglial/macrophage‐related genes including cytokines, chemokines, MHC class II antigens, lysozyme and the critical functional receptor, CSF‐1R. Isolated E‐GBM‐derived tumor cells were also capable of phagocytosis and cytokine production. Treating E‐GBM‐derived tumor cells with the BRAF‐V600E inhibitor, PLX4032 (vemurafenib), resulted in a dose‐dependent reduction in cell viability that was amplified by addition of the CSF‐1R inhibitor, BLZ945. The present case provides insight into the cellular nature of E‐GBM and introduces several possibilities for effective targeted therapy for these patients.

Perivascular areas of the brain harbor multipotent stem cells. We recently demonstrated that after a stroke, brain pericytes exhibit features of multipotent stem cells. Moreover, these ischemia-induced multipotent stem cells (iSCs) are present within ischemic areas of the brain of patients diagnosed with stroke. Although increasing evidence shows that iSCs have traits similar to those of mesenchymal stem cells (MSCs), the phenotypic similarities and differences between iSCs and MSCs remain unclear. In this study, we used iSCs extracted from stroke patients (h-iSCs) and compared their neurogenic potential with that of human MSCs (h-MSCs) in vitro. Microarray analysis, fluorescence-activated cell sorting, immunohistochemistry, and multielectrode array were performed to compare the characteristics of h-iSCs and h-MSCs. Although h-iSCs and h-MSCs had similar gene expression profiles, the percentage expressing the neural stem/progenitor cell marker nestin was significantly higher in h-iSCs than in h-MSCs. Consistent with these findings, h-iSCs, but not h-MSCs, differentiated into electrophysiologically functional neurons. In contrast, although both h-iSCs and h-MSCs were able to differentiate into several mesodermal lineages, including adipocytes, osteocytes, and chondrocytes, the potential of h-iSCs to differentiate into adipocytes and osteocytes was relatively low. These results suggest that compared with h-MSCs, h-iSCs predominantly exhibit neural rather than mesenchymal lineages. In addition, these results indicate that h-iSCs have the potential to repair the injured brain of patients with stroke by directly differentiating into neuronal lineages.

Ischemic stroke caused by cerebral artery occlusion induces neurological deficits because of cell damage or death in the central nervous system. Given the recent therapeutic advances in reperfusion therapies, some patients can now recover from an ischemic stroke with no sequelae. Currently, reperfusion therapies focus on rescuing neural lineage cells that survive in spite of decreases in cerebral blood flow. However, vascular lineage cells are known to be more resistant to ischemia/hypoxia than neural lineage cells. This indicates that ischemic areas of the brain experience neural cell death but without vascular cell death. Emerging evidence suggests that if a vascular cell-mediated healing system is present within ischemic areas following reperfusion, the therapeutic time window can be extended for patients with stroke. In this review, we present our comments on this subject based upon recent findings from lethal ischemia following reperfusion in a mouse model of stroke.