Examination of Risk Factors and Expression Patterns of Atypical Femoral Fractures Using the Japanese Adverse Drug Event Report Database: A Retrospective Pharmacovigilance Study.

Atypical femoral fracture (AFF) is a rare complication related to the use of bisphosphonates (BPs). Herein, we analyzed the risk factors and onset patterns of AFF using the Japanese Adverse Drug Event Report database and reported the findings. First, the independent risk factors for AFF were gender (female), high body mass index, and medical history of osteoporosis, arthritis, and systemic lupus erythematosus (SLE). Drug-related risk factors for AFF included BPs (i.e., alendronic acid, ibandronic acid, etidronic acid, zoledronic acid, minodronic acid, risedronic acid), denosumab, prednisolone, lansoprazole, rabeprazole, exemestane, letrozole, eldecalcitol, and menatetrenone. Therefore, it appears that AFF is influenced by a combination of patient backgrounds and drugs, and that the risk of developing AFF is particularly high in patients with fragile bones (e.g., osteoporosis, arthritis, and SLE). Second, in the analysis of AFF onset patterns, the onset of AFF from BPs and denosumab took a long time (>1 year) to develop. Analysis using a Weibull distribution showed wear-out failure-type AFF onset for BPs and denosumab, and both osteoporosis and cancer patients with long-term administration of these drugs showed a tendency to have an increased risk of onset. AFF developed earlier in osteoporosis patients with long-term administration of BPs and denosumab than in cancer patients.

An immunohistochemical study of placental syncytiotrophoblasts in neonatal hemochromatosis.

INTRODUCTION: Neonatal hemochromatosis (NH) is a rare neonatal disorder that results in liver cirrhosis with hemosiderin deposition in the liver and other organs, similarly to hereditary hemochromatosis. Excess iron is transferred from the mother to fetus through the placenta in NH. We examined the expression of iron metabolism-related substances in placental syncytiotrophoblasts (STB) by immunostaining to clarify how the transfer of iron through STB increases in NH. METHODS: Immunostaining was performed using formalin-fixed, paraffin-embedded sections of placentae from three NH cases, four gestational age-matched controls, and, depending on the antibody examined, five to seven full-term controls. The reactivity of immunostaining was assessed by averages of scores assigned by 3 researchers. RESULTS: On the microvillar surface of STB, the reactions of the antibodies against transferrin receptor 1 (TFR1), transferrin, ferritin, hepcidin, ferroportin, divalent metal transporter-1 (DMT1), hephaestin, and HFE were stronger in NH than in controls. In the cytoplasm, the reactions of antibodies against TFR1, transferrin, ferritin, hepcidin, DMT1, hephaestin, HFE, and ZIP 14 were stronger in NH than in gestational age-matched controls. Among these reactions, those of anti-TFR1 antibody on the surface of STB in NH was especially marked. DISCUSSION: In the placenta of NH, increases in expressions of TFR1, transferrin, and ferritin of which those of TFR1 were especially marked, reflect increased iron influx from the mother to fetus. The hepcidin observed on the surface and in the cytoplasm of STB of NH is suggested to be from the mother, possibly to compensate for the decreased fetal liver-derived hepcidin.

Immunohistochemical analysis of transporters related to clearance of amyloid-ß peptides through blood-cerebrospinal fluid barrier in human brain.

A large number of previous reports have focused on the transport of amyloid-ß peptides through cerebral endothelial cells via the blood-brain barrier, while fewer reports have mentioned the transport through the choroid plexus epithelium via the blood-cerebrospinal fluid barrier. Concrete roles of these two pathways remain to be clarified. In this study, we immunohistochemically examined the expression of transporters/receptors that are supposed to be related to the clearance of amyloid-ß peptides in the choroid plexus epithelium, the ventricular ependymal cells and the brain microvessels, using seven autopsied human brains. In the choroid plexus epithelium, immunoreactivity for low-density lipoprotein receptor (LDLR), LDLR-related protein 1 (LRP1), LRP2, formylpeptide receptor-like 1 (FPRL1), ATP-binding cassette (ABC) transporter-A1 (ABCA1), ABCC1 and ABCG4 was seen in 7 of 7 brains, while that for ABCB1, ABCG2, RAGE and CD36 was seen in 0-2 brains. In the ventricular ependymal cells, immunoreactivity for CD36, LDLR, LRP1, LRP2, FPRL1, ABCA1, ABCC1 and ABCG4 was seen in 6-7 brains, while that for ABCB1, ABCG2 and RAGE was seen in 0-1 brain. Immunoreactivity for insulin-degrading enzyme (IDE) was seen in three and four brains in the choroid plexus epithelium and the ventricular ependymal cells, respectively. In addition, immunoreactivity for LDLR, ABCB1 and ABCG2 was seen in over 40 % of the microvessels (all seven brains), and that for FPRL1, ABCA1, ABCC1 and RAGE was seen in over 5 % of the microvessels (4-6 brains), while that for CD36, IDE, LRP1, LRP2 and ABCG4 was seen in less than 5 % of the microvessels (0-2 brains). These findings may suggest that these multiple transporters/receptors and IDE expressed on the choroid plexus epithelium, ventricular ependymal cells and brain microvessels complementarily or cooperatively contribute to the clearance of amyloid-ß peptides from the brain.

An immunohistochemical study of human platelets using a rabbit antibody against H18-K24 of apolipoprotein CIII (HATKTAK).

H18-K24 of human apolipopotein CIII (Apo CIII) (HATKTAK) is an activator of the macromolecular activators of phagocytosis from platelets (MAPPs). Using a rabbit antibody against HATKTAK, we performed an immunohistochemical study of human platelets. Indirect ELISA showed that this antibody reacts with Apo CIII-derived peptides with a C-terminal of HATKTAK, but not with Apo CIII. Immunoelectron microscopy revealed that reaction of anti-HATKTAK antibody occurred in the pseudopods of activated platelets. In blood coagula produced from the peripheral blood and formalin-fixed after various incubation periods, reaction of this antibody with platelets appeared rapidly with a peak at 3 to 6 h of incubation, and then diminished gradually. Leukocytes in the blood coagula were stained strongly positive. In tissue sections, fresh thrombi and hemorrhages with slight fibrin formation revealed a positive response of platelets to anti-HATKTAK antibody, whereas older ones with leukocytic infiltration, fibrin formation and organization did not. In addition to platelets, endothelial cells and leukocytes were stained positive by anti-HATKTAK antibody. All of the positive reactions by anti-HATKTAK antibody disappeared or diminished by co-incubation with HATKTAK. In conclusion, the anti-HATKTAK antibody reveals platelets during the early phase of activation.

Effects of flow patterns and hemodynamic force on vascular endothelium in the temporary arteriovenous shunt loop in rabbits.

The purpose of this study was to investigate whether there is a risk of thrombosis in the temporary arteriovenous shunt loop (TAVSL). The authors established a TAVSL model in the rabbit. Experimental groups were divided into non-heparin treated and heparin treated. The maximum blood flow volume, blood viscosity, and radius of curvature were measured, and the Reynolds number and the sheer stress were calculated. Computational fluid dynamics (CFD) was used to predict the flow pattern in the TAVSL, and these predicted data were compared with histological results. Early occlusion was noted in 70% (7/10) of the non-heparin-treated group and 22% (2/9) of the heparin-treated group. CFD analysis predicted a high shear stress at the arterial anastomosis region and the outer luminal surface of the curved section. The intimal structure at the luminal surface of the curved section was extensively lost histologically. In the patent group, severe stenosis of the lumen was noted at the apex of the loop due to an organized thrombus. Thus, thrombosis is likely to occur in the TAVSL due to endothelium injury caused by high shear stress, and this results in the formation of white thrombi at an early stage and an organized thrombus at a late stage.

CD36 expression in the brains of SAMP8.

SAMP8, senescence accelerated mice with age-related deficits in memory and learning, are known to show age-related increases of amyloid precursor protein (APP) and immunopositivity for amyloid-ß (Aß) proteins, and moreover to be under elevated oxidative stress. The elevated expression of class B scavenger receptor CD36, which is the receptor of oxidized LDL and also one of efflux transporters of Aß proteins in the cerebral vessels, is thought to mediate free radical production in cerebral ischemia and induce oxidative stress. Accordingly, by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical techniques, we examined whether the expression of CD36 was increased in the brains of 10-12-week-old SAMP8 with elevated oxidative stress. Ten to 12-week-old SAMR1 mice were used as controls without the features. The gene and protein expression of CD36 was significantly higher in the brains of SAMP8 than those of SAMR1. Confocal microscopic examination revealed that the CD36 immunoreactivity was seen in the cytoplasm of endothelial cells and F4/80-positive perivascular cells of the brains. These findings indicate that the expression of CD36 in the brains of SAMP8 is increased compared with that of SAMR1.

Prenatal high-dose immunoglobulin treatment for neonatal hemochromatosis: a case report and review of the literature.

Neonatal hemochromatosis is a difficult disorder to cure, and it has a high rate of recurrence. High-dose immunoglobulin treatment is very effective as prenatal treatment for recurrent neonatal hemochromatosis. A 34-year-old pregnant Japanese woman underwent high-dose immunoglobulin treatment for recurrent neonatal hemochromatosis. High-dose non-specific intravenous immunoglobulin (1 g/kg bodyweight) was administered to the mother intravenously every week from 18 until 36 gestational weeks. A male infant was delivered at 37 weeks of gestation, and his condition was favorable, including hepatic function. The use of γ-globulin for neonatal hemochromatosis appears adequately validated by experience.

Effects of D-allose on the endocytic activity of dendritic cells and the subsequent stimulation of T cells.

We examined the effects of a rare sugar, D-allose, which is 6-carbon monosaccharide, on endocytosis and T cell stimulation by dendritic cells (DCs). The endocytosis of BCG-anti-BCG immune complexes by DCs markedly decreased in D-allose-containing medium. Co-culture with T cells (mixed leukocyte reaction, MLR) of DCs, which had been exposed to BCG in D-allose-supplemented medium, induced apoptosis of CD4(+) T cells in a manner dependent on D-allose concentration. After the MLR, DCs cultured in the medium with D-allose expressed less CD40 and more Fas ligands than those cultured without D-allose. It was suggested that the functions of DCs, internalization, processing and the subsequent antigen presentation to T cells, are down-regulated via the action of d-allose.

Platelet high-density lipoprotein activates transferrin-derived phagocytosis activators, MAPPs, following thrombin digestion.

Macromolecular activators of phagocytosis from platelets (MAPPs), transferrin-derived phagocytosis activators released from platelets, activate leukocytic phagocytosis via Fcγ receptors. It has been found that MAPPs can be prepared using stored platelets or their lysate. Using this artificial MAPP production system, it has been found that they can be produced from precursors (tetrameric and dimeric transferrins) following reaction with a low-molecular-weight (LMW) activator of MAPPs, which is liberated from a high-molecular-weight activator of MAPP (HMW activator) by reaction with thrombin. In this study, the HMW activator in platelet lysate was characterized by assaying phagocytosis of washed neutrophils. In an ultracentrifugation study of the platelet lysate, HMW activator activity was observed in the fraction corresponding to the density of high-density lipoprotein (HDL). The activity was observed in the apolipoproteins obtained from the HDL fraction. Among the apolipoproteins tested only apolipoprotein CIII showed the activity to produce MAPP in vitro. Affinity chromatography of the apolipoproteins from the HDL fraction of the platelet lysate using an anti-apolipoprotein CIII column revealed that the substance that binds with the antibody showed MAPP-forming activity. In a gel filtration study of thrombin-treated apolipoprotein CIII, a peak of LMW activator activity was observed for fractions with a molecular size smaller than that of apolipoprotein CIII. Finally, MAPP-forming activity of HDL obtained from the plasma was examined. MAPP was formed only when delipidized HDL was used. In conclusion, it is suggested that platelet HDL is the HMW activator and that this activation is achieved via apolipoprotein CIII after thrombin reaction in platelets.

Blockade of AT1 receptors protects the blood-brain barrier and improves cognition in Dahl salt-sensitive hypertensive rats.

BACKGROUND: The present study tested the hypothesis that inappropriate activation of the brain renin-angiotensin system (RAS) contributes to the pathogenesis of blood-brain barrier (BBB) disruption and cognitive impairment during development of salt-dependent hypertension. Effects of an angiotensin II (AngII) type-1 receptor blocker (ARB), at a dose that did not reduce blood pressure, were also examined. METHODS: Dahl salt-sensitive (DSS) rats at 6 weeks of age were assigned to three groups: low-salt diet (DSS/L; 0.3% NaCl), high-salt diet (DSS/H; 8% NaCl), and high-salt diet treated with ARB, olmesartan at 1 mg/kg. RESULTS: DSS/H rats exhibited hypertension, leakage from brain microvessels in the hippocampus, and impaired cognitive functions, which were associated with increased brain AngII levels, as well as decreased mRNA levels of tight junctions (TJs) and collagen-IV in the hippocampus. In DSS/H rats, olmesartan treatment, at a dose that did not alter blood pressure, restored the cognitive decline, and ameliorated leakage from brain microvessels. Olmesartan also decreased brain AngII levels and restored mRNA expression of TJs and collagen-IV in DSS/H rats. CONCLUSIONS: These results suggest that during development of salt-dependent hypertension, activation of the brain RAS contributes to BBB disruption and cognitive impairment. Treatment with an ARB could elicit neuroprotective effects in cognitive disorders by preventing BBB permeability, which is independent of blood pressure changes.

Atrial natriuretic peptide enhances recovery from ischemia/reperfusion-induced renal injury in rats.

Recovery from ischemic acute kidney injury requires the replacement of damaged tubular cells. This repair process involves epidermal growth factor (EGF) synthesized in medullary the thick ascending limbs (mTAL) of Henle. Atrial natriuretic peptide (ANP), a hormone synthesized by the cardiac atria, increases glomerular filtration rate and renal medullary blood flow. However, the effects of ANP on renal recovery after I/R-induced renal injury remain unclear. We therefore examined whether human ANP enhances recovery from I/R-induced renal injury by reducing damage to EGF-producing kidney cells in a rat model. Male Wistar rats weighing 200-240 g were observed for 48 h after reperfusion following 45-min renal ischemia. Rats were intravenously administered alpha-human ANP (alpha-hANP) at 0.2 microg/kg/min beginning immediately after ischemia and continuing for 2 h after reperfusion. Outer medullary blood flow (OMBF), EGF mRNA, serum blood urea nitrogen (BUN) and creatinine levels as indicators of glomerular function were measured, while urinary N-acetyl beta-D-glucosaminidase (NAG) was used as a specific indicator of proximal tubular function. OMBF was increased by alpha-hANP after reperfusion and maintained significantly higher mRNA level of EGF in the kidney 24 h after reperfusion. I/R-induced increases in serum concentrations of BUN and creatinine and urinary concentrations of NAG were also reduced by alpha-hANP, with improved histopathological changes, including acute tubular necrosis at 24-48 h after reperfusion. This report is the first to demonstrate that alpha-hANP accelerates recovery following renal ischemic insult by reducing the damage to EGF-producing kidney cells.

The expression of LDL receptor in vessels with blood-brain barrier impairment in a stroke-prone hypertensive model.

We previously reported that the blood-brain barrier (BBB) function was deteriorated in vessels located in the hippocampus in stroke-prone spontaneously hypertensive rats (SHRSP). In order to assess whether substances with oxidative stress such as amyloid-beta (Abeta) can be scavenged in the BBB-damaged vessels, we examined the gene expression of representative efflux and influx transporters of Abeta, such as low-density lipoprotein receptor (LDLR), LDL-related protein 1 (LRP1), and the receptor for advanced glycation end product (RAGE) in the hippocampus of SHRSP with the BBB impairment and Wistar Kyoto rats (WKY) without the impairment. Real-time quantitative reverse transcriptase-polymerase chain reaction analysis revealed that LDLR gene expression was increased in the samples of SHRSP compared with those of WKY, while there was no significant difference in LRP1 or RAGE gene expression between SHRSP and WKY. Western blot analysis revealed that the protein expression of LDLR was increased in the samples of SHRSP compared with those of WKY. Immunoelectron microscopic examination revealed that the LDLR expression was seen in the luminal and abluminal cytoplasmic membranes and vesicular structures of the endothelial cells and the cytoplasm of perivascular cells, especially in vessels with immunoreactivity of albumin showing increased vascular permeability. These findings suggest that the expression of LDLR was increased in the hippocampus of SHRSP compared with that of WKY and was seen in the luminal and abluminal cytoplasmic membranes and vesicular structures of endothelial cells, suggesting a role of LDLR in the vessels with BBB impairment.

[Percutaneous transthoracic needle biopsies under a guide of real-time three image computed tomography].

PURPOSES: Experiences of percutaneous transthoracic needle biopsies under a guide of a real time 3 image display computed tomography (3 image CT) is reported. MATERIALS AND METHODS: Twenty seven biopsies from 23 patients were performed. For 3 image CT, Somatom was used. This equipment can render 3 pictures of serial slices on a screen simultaneously and have X-ray exploration-reduction system for both the patients (35% reduction) and operator's hands (72% reduction). RESULTS: The median size of the masses was 1.7 (0.5-6.3) cm; the median distance from the pleura to the mass was 0.66 (0-6.5) cm; and the median time to perform biopsies was 12 minutes. We had only 3 failed cases to obtain biopsied specimen (11%). COMPLICATIONS: Needle biopsy of the lung lesion under a guide of a 3 sectional CT is a safe and timesaving method with a high success rate to obtain biopsied tissues even for small lesions or difficult lesion.

Macrophage involvement in Epstein-Barr virus-related tumors.

Epstein-Barr virus (EBV) is known as a causative agent of Burkitt's lymphoma, nasopharyngeal carcinoma and approximately 10% of stomach carcinoma cases. In other human cancers, EBV gene expression including lytic infection protein detected using in situ hybridization and immunofluorescence staining has been reported. Moreover, the expression and replication of EBV genes in cultured normal macrophages and in histiocytes of Langerhans' cell histiocytosis have been identified. The aim of this study was to examine EBV expression in macrophages in other EBV-associated human tumors. Forty-one cases of EBV-associated tumors, which had been confirmed to express EBV, were examined. Tissue sections after in situ hybridization were double-stained immunohistochemically with the monoclonal anti-CD68 antibody. EBV expression in macrophages in the lesions of nasopharyngeal carcinoma, oral cancer, thyroid carcinoma, renal cell carcinoma, testicular carcinoma, uterine carcinoma, cutaneous T-cell lymphoma and anaplastic large-cell lymphoma was identified, whereas macrophages in normal or non-cancerous lesions showed no EBV expression. Many tumor-associated macrophages in EBV-related tumors carry EBV, which appears to induce the EBV lytic infection of macrophages. Therefore, the possibility that the lytic infection of macrophages by EBV and the resulting inflammation play certain roles in the oncogenesis of EBV-associated human tumors was raised.

Age-related changes in P-glycoprotein expression in senescence-accelerated mouse.

P-glycoprotein, the gene product of ATP-binding cassette, sub-family B (Abcb1), is a representative efflux transporter of cerebral vessels. It was recently reported that the expressions of P-glycoprotein and Abcb1 gene were increased in hippocampal vessels with blood-brain barrier (BBB) damage in stroke-prone hypertensive rats. SAMP8, senescence-accelerated mice with age-related deficits in memory and learning, are known to show age-related damage of BBB. Accordingly, in this study, we examined the P-glycoprotein expression and the gene expression (Abcb1a/b) by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical techniques. SAMR1, which has a spontaneous retroviral insertional mutation in Abcb1a gene, was used to assess the effects of Abcb1a gene mutation. The brain samples of SAMR1 showed decreased expressions of P-glycoprotein and Abcb1a genes and increased expression of Abcb1b gene, compared with those of SAMP8 mice. The P-glycoprotein expression increased with aging in the brain samples of SAMP8, but not in those of SAMR1. The gene expressions of Abcb1a and Abcb1b increased with aging in the brain samples of SAMP8. Immunosignals of P-glycoprotein were seen in vessel walls, mainly in the cytoplasm of CD34-positive endothelial cells and partially in astrocytes, in all mice. These findings indicate that the expressions of Abcb1a and Abcb1b genes and their gene products, P-glycoprotein, were increased with aging in SAMP8, suggesting age-related response to prevent toxic substance from accumulating in the brains of SAMP8.

RAGE, LDL receptor, and LRP1 expression in the brains of SAMP8.

SAMP8, senescence-accelerated mice with age-related deficits in memory and learning, are known to show age-related increases of amyloid precursor protein (APP) expression and to be under elevated oxidative stress. The receptor for advanced glycation end product (RAGE) is a representative influx transporter of APP or amyloid-beta (A beta) protein in cerebral vessels, while low-density lipoprotein receptor (LDLR) and LDL-related protein 1 (LRP1) are efflux transporters. These receptors play roles not only in clearance of A beta protein but also in control of oxidative stress. In this study, we examined the gene and protein expressions of these receptors, by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical techniques. SAMR1 mice with lower expression of APP were as controls. The gene and protein expressions of RAGE were lower in SAMP8 brains than in SAMR1. Those of LDLR were higher in SAMP8 brains than those of SAMR1. There were no differences in the expressions of LRP1 between SAMP8 and SAMR1. Immunosignals of RAGE and LDLR were seen in the cytoplasm of CD34-positive endothelial cells and also in astrocytes, in both strains of mice. These findings suggest that the lower expression of RAGE and the higher expression of LDLR may contribute to clearance of toxic substances and, in addition, be related to elevated oxidative stress in SAMP8 brains.

Abcb1a and Abcb1b expression in senescence-accelerated mouse (SAM).

It was recently reported that some strains of senescence-accelerated mouse (SAM) including SAMR1 had a spontaneous retroviral insertional mutation in the ATP-binding cassette, sub-family B, member 1A (Abcb1a) gene, while other strains including SAMP8 had not. The Abcb1 gene product, P-glycoprotein, is a representative efflux transporter of cerebral vessels. In this study, using brain samples of SAMR1, Abcb1a gene-mutant mice, and of SAMP8 without that mutation, we examined the gene expression of some representative ATP-binding cassettes, such as Abcb1a, Abcb1b, Abcc, and Abcg2, and the protein expression of P-glycoprotein by real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical techniques. The gene expression of Abcb1a was decreased in the brain samples of SAMR1 compared with those of SAMP8, while that of Abcb1b was increased in the samples of SAMR1 compared with those of SAMP8. There were no differences in the gene expression of Abcc and Abcg2 between the samples of SAMR1 and SAMP8. The protein expression of P-glycoprotein was decreased in the brain samples of SAMR1 compared with those of SAMP8. Immunosignals of P-glycoprotein were seen in vessels walls, mainly CD34-positive endothelial cells and partially astrocytic cells, in both mice. These findings indicate that SAMR1, Abcb1a-mutant mice, showed decreased expression of Abcb1a gene and P-glycoprotein and increased gene expression of Abcb1b, compared with those of SAMP8 without that mutation, suggesting no clear effect of increased gene expression of Abcb1b on decreased expression of P-glycoprotein. The combination of SAMR1 and SAMP8 may be a good tool to investigate which transporter, Abcb1a or Abcb1b, can be used in drug delivery into the brain.

Medulloblastoma with myogenic differentiation showing double immunopositivity for synaptophysin and myoglobin.

Reported herein is a case of medulloblastoma with myogenic differentiation in a 3-year-old girl who died 1 year after appearance of clinical signs. Magnetic resonance imaging indicated a mass lesion in the cerebellar vermis. She underwent total resection of the tumor, followed by chemotherapy and radiotherapy in the brain and spinal cord. The resected specimen mainly consisted of densely packed cells with round-to-oval highly chromatic nuclei surrounded by scanty cytoplasm and focally of long spindle-shaped cells with elongated nuclei and eosinophilic cytoplasm showing discernible cross-striations. Immunohistochemistry indicated partial expression of synaptophysin in the former area and focal expression of desmin in the latter area. The diagnosis was medulloblastoma with myogenic differentiation, also known as medullomyoblastoma. Autopsy indicated disseminated proliferation of immature neuroglial cells with highly chromatic nuclei and scanty cytoplasm showing partial expression of synaptophysin, neurofilaments, and GFAP, and focal proliferation of round-to-oval immature cells showing immunoreactivity of myoglobin. The tumor cells had large nuclei, frequent mitoses, apoptoses, nuclear molding, and cell wrapping, indicating moderate anaplasia. Their Ki-67 labeling index was 54%. In addition, some tumor cells had double immunopositivity for synaptophysin or neurofilament and myoglobin, suggesting that the neuroectodermal cells may undergo differentiation into rhabdomyoblasts.

The expression of matrix metalloproteinase-13 is increased in vessels with blood-brain barrier impairment in a stroke-prone hypertensive model.

We previously reported that the blood-brain barrier (BBB) function was deteriorated in vessels located in the hippocampus, but not the cerebral cortex, in 3-month-old stroke-prone spontaneously hypertensive rats (SHRSP). Recently published data suggest that matrix metalloproteinase (MMP)-2 and MMP-9 play a critical role in the BBB disruption in stroke or cerebral ischemia. In this study, we examined gene and protein expressions of MMPs in the BBB-damaged hippocampal vessels of 3-month-old SHRSP, in the cerebral cortical vessels without BBB damage of SHRSP, and in the hippocampal and cerebral cortical ones without BBB damage of 3-month-old Wistar Kyoto (WKY) rats. The expressions of MMPs were examined by real-time quantitative reverse transcriptase-PCR (RT-PCR), western blotting and immunohistochemical techniques. The gene and protein expressions of MMP-13 were significantly increased in the hippocampal samples of SHRSP compared with samples without BBB damage, such as cerebral cortical samples of SHRSP or hippocampal samples of WKY. Immunostaining of MMP-13 was seen in the cytoplasm of ED-1-positive perivascular cells in both rats and was colocalized with those of type IV collagen or osteopontin. The type IV collagen was also localized in the basement membrane. These findings indicate that the expression of MMP-13 is increased in BBB-damaged hippocampal vessels in hypertensive SHRSP compared with vessels without BBB impairment in normotensive WKY rats and may be involved in vascular remodeling.