Shirabe Matsumoto

Expression of MCP-1 and fractalkine on endothelial cells and astrocytes may contribute to the invasion and migration of brain macrophages in ischemic rat brain lesions.

Some macrophages expressing NG2 chondroitin sulfate proteoglycan (NG2) and the macrophage marker Iba1 accumulate in the ischemic core of a rat brain subjected to transient middle cerebral artery occlusion (MCAO) for 90 min. These cells are termed BINCs (for brain Iba1+/NG2+ cells) and may play a neuroprotective role. Because BINCs are bone marrow‐derived cells, they are able to invade ischemic tissue after the onset of an ischemic insult. In this study, chemokine‐based mechanisms underlying the invasion of BINCs or their progenitor cells were investigated. We found that isolated BINCs expressed mRNA encoding CCR2 and CX3CR1 at high levels. Cultured astrocytes expressed mRNA encoding their ligands, MCP‐1 and fractalkine. Recombinant MCP‐1 and/or fractalkine, as well as astrocytes, induced the migration of BINCs in vitro. mRNA for MCP‐1, fractalkine, CCR2, and CX3CR1 was expressed in the ischemic core during the acute phase of the ischemic event. Immunohistochemical studies revealed that vascular endothelial cells and astrocytic endfeet expressed MCP‐1 and fractalkine, respectively, in the ischemic core during the acute phase. CCR2+/Iba1+ monocytes attached to the inside of the vascular wall at 1 day postreperfusion (dpr), and there were CCR2+/CX3CR1+ macrophage‐like cells in the parenchyma in the ischemic lesion core at 2 dpr, which may be the progenitors for BINCs. These results suggest that CCR2+ monocytes are first attracted to the ischemic lesion by MCP‐1+ endothelial cells and migrate toward fractalkine+ astrocytic endfeet through the disrupted blood–brain barrier. Thus, chemokines may play a critical role in the accumulation of neuroprotective BINCs.

CD200+ and CD200− macrophages accumulated in ischemic lesions of rat brain: The two populations cannot be classified as either M1 or M2 macrophages

Two types of macrophages in lesion core of rat stroke model were identified according to NG2 chondroitin sulfate proteoglycan (NG2) and CD200 expression. NG2(+) macrophages were CD200(-), and vice versa. NG2(-) macrophages expressed two splice variants of CD200 that are CD200L and CD200S. CD200(+) macrophages expressed CD8, CD68, CD163, CCL2, inducible nitric oxide synthase, interleukin-1β, Toll-like receptor 4 and transforming growth factor β, whilst NG2(+) cells expressed a costimulatory factor CD86. Both cell types expressed insulin-like growth factor 1 and CD200R. These results demonstrate that the two macrophage types cannot be classified as either M1 or M2.

Usefulness of an Image Fusion Model Using Three-Dimensional CT and MRI with Indocyanine Green Fluorescence Endoscopy as a Multimodal Assistant System in Endoscopic Transsphenoidal Surgery.

Purpose. We investigate the usefulness of multimodal assistant systems using a fusion model of preoperative three-dimensional (3D) computed tomography (CT) and magnetic resonance imaging (MRI) along with endoscopy with indocyanine green (ICG) fluorescence in establishing endoscopic endonasal transsphenoidal surgery (ETSS) as a more effective treatment procedure. Methods. Thirty-five consecutive patients undergoing ETSS in our hospital between April 2014 and March 2015 were enrolled in the study. In all patients, fusion models of 3D-CT and MRI were created by reconstructing preoperative images. In addition, in 10 patients, 12.5 mg of ICG was intravenously administered, allowing visualization of surrounding structures. We evaluated the accuracy and utility of these combined modalities in ETSS. Results. The fusion model of 3D-CT and MRI clearly demonstrated the complicated structures in the sphenoidal sinus and the position of the internal carotid arteries (ICAs), even with extensive tumor infiltration. ICG endoscopy enabled us to visualize the surrounding structures by the phasic appearance of fluorescent signals emitted at specific consecutive elapsed times. Conclusions. Preoperative 3D-CT and MRI fusion models with intraoperative ICG endoscopy allowed distinct visualization of vital structures in cases where tumors had extensively infiltrated the sphenoidal sinus. Additionally, the ICG endoscope was a useful real-time monitoring tool for ETSS.

Utility of three-dimensional computed tomography for anatomical assistance in endoscopic endonasal transsphenoidal surgery

Endoscopic endonasal transsphenoidal surgery (ETSS) has been widely applied to pituitary adenomas. However, anatomical orientation is difficult when structures of the sphenoidal sinus are complicated. This study investigated the usefulness of three-dimensional computed tomography (3D-CT) modeling in planning surgical procedures for ETSS and providing anatomical guidance during surgery. CT data from 99 consecutive patients with pituitary adenoma treated between January 2008 and March 2014 were used to reconstruct 3D-CT models. Based on these images, the architecture of sphenoidal sinus, particularly structures surrounding the sellar floor, was visualized for preoperative simulation of surgical procedures. These 3D-CT images were also compared to surgical views during ETSS to evaluate applicability of the images. These models clearly demonstrated the morphology of the nasal cavity and structures of the sphenoidal sinus, including bony prominences of the internal carotid arteries (ICAs) and optic canals by successively eliminating sphenoidal structures. The 3D-CT images permitted determination of the maximum marginal line of the opening of the sellar floor by presenting vital structures such as ICAs and optic canals. With this 3D-CT model, the surgeon could access the sella more easily, open the floor widely enough for each individual patient, and resect the tumor maximally without complications. Preoperative 3D-CT models distinctly visualized the optic canals, bilateral ICAs, and complicated structures of sphenoidal septa. The 3D-CT images were useful for preoperative planning and as a road map during endoscopic surgery for pituitary adenoma, facilitating maximum tumor resection without complications.

A Truncated form of CD200 (CD200S) Expressed on Glioma Cells Prolonged Survival in a Rat Glioma Model by Induction of a Dendritic Cell-Like Phenotype in Tumor-Associated Macrophages.

CD200 induces immunosuppression in myeloid cells expressing its receptor CD200R, which may have consequences for tumor immunity. We found that human carcinoma tissues express not only full-length CD200 (CD200L) but also its truncated form, CD200S. Although CD200S is reported to antagonize the immunosuppressive actions of CD200L, the role of CD200S in tumor immunity has never been investigated. We established rat C6 glioma cell lines that expressed either CD200L or CD200S; the original C6 cell line did not express CD200 molecules. The cell lines showed no significant differences in growth. Upon transplantation into the neonatal Wistar rat forebrain parenchyma, rats transplanted with C6-CD200S cells survived for a significantly longer period than those transplanted with the original C6 and C6-CD200L cells. The C6-CD200S tumors were smaller than the C6-CD200L or C6-original tumors, and many apoptotic cells were found in the tumor cell aggregates. Tumor-associated macrophages (TAMs) in C6-CD200S tumors displayed dendritic cell (DC)-like morphology with multiple processes and CD86 expression. Furthermore, CD3+, CD4+ or CD8+ cells were more frequently found in C6-CD200S tumors, and the expression of DC markers, granzyme, and perforin was increased in C6-CD200S tumors. Isolated TAMs from original C6 tumors were co-cultured with C6-CD200S cells and showed increased expression of DC markers. These results suggest that CD200S activates TAMs to become DC-like antigen presenting cells, leading to the activation of CD8+ cytotoxic T lymphocytes, which induce apoptotic elimination of tumor cells. The findings on CD200S action may provide a novel therapeutic modality for the treatment of carcinomas.

Microvasculature of carotid atheromatous plaques: Hemorrhagic plaques have dense microvessels with fenestrations to the arterial lumen

BACKGROUND Microvessels in atheromatous plaques are well known to play a role in plaque vulnerability associated with intraplaque hemorrhage, but their architecture remains unclear. The morphometry of the microvasculature and hemorrhage of human carotid atheromatous plaques (CAPs) were evaluated, and 3-dimensional (3D) reconstruction of the microvessels was performed. METHODS CAPs were obtained by endarterectomy in 42 patients. The specimens were analyzed using light microscopy. Plaque hemorrhage was defined as an area-containing red blood cells (>1 mm2). To determine the histopathologic features of plaque hemorrhage, the plaque area was divided into 4 regions: cap, shoulder, lipid/necrotic core, and media. Then, the density of microvessels and macrophages in each region was quantified. Two representative lesions with either hemorrhagic or nonhemorrhagic plaque were cut into 90 serial sections. The sections were double stained with anti-CD34 and anti-α smooth muscle actin antibodies, scanned using a digital microscope, and reconstructed using TRI-SRF2 software. RESULTS The hemorrhagic plaques showed a higher density of microvessels than nonhemorrhagic plaques in the shoulder, cap, and lipid/necrotic core (P=.03, .009, and .001, respectively), and there was positive correlations between its density and macrophages in each regions (P<.001, .001, and .019, respectively). 3D imaging also revealed dense microvessels with a network structure in the cap and shoulder regions of hemorrhagic plaques, and some of the vessels were fenestrated to the arterial lumen. CONCLUSIONS The microvasculature of plaques with intraplaque hemorrhage was dense, some of which fenestrated to the arterial lumen. The pathologic 3D imaging revealed precise architecture of microvasculature of plaques.

Plasma thrombin-cleaved osteopontin as a potential biomarker of acute atherothrombotic ischemic stroke.

We investigated whether thrombin-cleaved osteopontin N-terminal is useful as a blood biomarker of acute atherothrombotic ischemic stroke. Acute ischemic stroke patients were prospectively evaluated with brain magnetic resonance imaging and cardiac evaluations for etiological diagnosis according to the Trial of Org 10172 in Acute Stroke Treatment classification. They were divided into the atherothrombotic and non-atherothrombotic groups. Thrombin-cleaved osteopontin N-terminal, osteopontin, matrix metalloproteinase-9, S100B, C-reactive protein and D-dimer levels were measured from blood samples collected at admission. After excluding patients who met the exclusion criteria or had stroke of other/undetermined etiology, 60 of the 100 patients initially enrolled were included in the final analysis. The ischemic stroke subtypes were atherothrombotic (n=28, 46.7%), cardioembolic (n=19, 31.7%) and lacunar (n=13, 21.7%). Thrombin-cleaved osteopontin N-terminal and matrix metalloproteinase-9 levels were significantly higher in the atherothrombotic than in the non-atherothrombotic group (median (interquartile range): 5.83  (0.0–8.6 ) vs. 0.0  (0.0–3.3) pmol l−1, P=0.03 and 544   (322–749 ) vs. 343   (254–485) ng ml−1, P=0.01, respectively). After adjustment for the prevalence of hypertension, diabetes and dyslipidemia, thrombin-cleaved osteopontin N-terminal levels of >5.47 pmol l−1 (odds ratio, 16.81; 95% confidence interval, 3.53–80.10) and matrix metalloproteinase-9 levels of >605.5 ng ml−1 (6.59; 1.77–24.60) were identified as independent predictors of atherothrombosis. Within 3 h from stroke onset, only thrombin-cleaved osteopontin N-terminal independently predicted atherothrombosis and thus may add valuable, time-sensitive diagnostic information in the early evaluation of ischemic stroke, especially the atherothrombotic subtype.

Identification of characteristic features of pineal germinoma that enhance accuracy of preoperative differentiation in pineal region tumors: its significance on optimum surgical treatment

The aim of the study is to identify characteristic features of pineal germinoma that enhance preoperative accuracy in differentiating germinoma from other pineal region tumors. Twenty-one consecutive patients with pineal region tumors were enrolled. In all patients, tumor resection was performed to verify the histology. Clinical records including upward gaze palsy of Parinaud’s syndrome and neuroimaging were analyzed. In addition, we evaluated the relationship between magnetic resonance imaging (MRI) findings and tumor progression patterns in pineal germinoma. Among 21 patients, 15 patients were diagnosed with germ cell tumor, 4 with pineal parenchymal cell tumor, and 2 with meningioma. Upward gaze palsy was seen in 11 patients; nine had pure germinomas and two had mixed germ cell tumors. These tumors occupied the pineal region with extension to the area of the mesodiencephalic junction (MDJ) and the bi-epithalamic area between the bilateral pulvinar and the third ventricle. Tumor involvement of the former area could cause upward gaze palsy by insulting the rostral interstitial nucleus of the medial longitudinal fasciculus located in the MDJ area. Tumor invasion into the latter area is commonly seen as a cardioid-shaped tumor as the tumor image on the axial MRI view. Upward gaze palsy and a cardioid-shaped tumor image on the axial MRI views were demonstrated to be specific features of pineal pure germinoma. It is suggested that combination of both features may become useful tools to preoperatively differentiate germinoma from other pineal tumors, resulting in achievement of the optimum treatment of pineal region tumors.

Sustained anti-inflammatory effects of TGF-β1 on microglia/macrophages

Ischemic brain injuries caused release of damage-associated molecular patterns (DAMPs) that activate microglia/macrophages (MG/MPs) by binding to Toll-like receptors. Using middle cerebral artery transiently occluded rats, we confirmed that MG/MPs expressed inducible nitric oxide synthase (iNOS) on 3days after reperfusion (dpr) in ischemic rat brain. iNOS expression almost disappeared on 7dpr when transforming growth factor-β1 (TGF-β1) expression was robustly increased. After transient incubation with TGF-β1 for 24h, rat primary microglial cells were incubated with lipopolysaccharide (LPS) and released NO level was measured. The NO release was persistently suppressed even 72h after removal of TGF-β1. The sustained TGF-β1 effects were not attributable to microglia-derived endogenous TGF-β1, as revealed by TGF-β1 knockdown and in vitro quantification studies. Then, boiled supernatants prepared from ischemic brain tissues showed the similar sustained inhibitory effects on LPS-treated microglial cells that were prevented by the TGF-β1 receptor-selective blocker SB525334. After incubation with TGF-β1 for 24h and its subsequent removal, LPS-induced phosphorylation of IκB kinases (IKKs), IκB degradation, and NFκB nuclear translocation were inhibited in a sustained manner. SB525334 abolished all these effects of TGF-β1. In consistent with the in vitro results, phosphorylated IKK-immunoreactivity was abundant in MG/MPs in ischemic brain lesion on 3dpr, whereas it was almost disappeared on 7dpr. The findings suggest that abundantly produced TGF-β1 in ischemic brain displays sustained anti-inflammatory effects on microglial cells by persistently inhibiting endogenous Toll-like receptor ligand-induced IκB degradation.

Truncated CD200 stimulates tumor immunity leading to fewer lung metastases in a novel Wistar rat metastasis model

CD200 mediates immunosuppression in immune cells that express its receptor, CD200R. There are two CD200 variants; truncated CD200 that lacks the part of N-terminal sequence necessary for CD200R binding (CD200S) and full-length CD200 (CD200L). We established a novel lung metastasis model by subcutaneously transplanting C6 glioma cells into the backs of neonatal Wistar rats. All transplanted rats developed large back tumors, nearly 90% of which bore lung metastases. To compare the effects of CD200S and CD200L on tumor immunity, CD200L (C6-L)- or CD200S (C6-S)-expressing C6 cells were similarly transplanted. The results showed that 100% of rats with C6-L tumors developed lung metastases, while metastases were found in only 44% of rats with C6-S tumors (n = 25). Tumors disappeared in approximately 20% of the C6-S-bearing rats, and these animals evaded death 180 d after transplantation, while all C6-L tumor-bearing rats died after 45 d. Next generation sequencing revealed that C6-S tumors expressed chemokines and granzyme B at much higher levels than C6-L tumors. Flow cytometry revealed that C6-S tumors contained more dead cells and more CD45+ cells, including natural killer cells and CD8+ lymphocytes. In particular, multiple subsets of dendritic cells expressing CD11c, MHC class II, CD8, and/or CD103 were more abundant in C6-S than in C6-L tumors. These results suggested that CD200S induced the accumulation of multiple dendritic cell subsets that activated cytotoxic T lymphocytes, leading to the elimination of metastasizing tumor cells.