Biomedical subjects

Masako Mitsumata

Publications and source records attributed to Masako Mitsumata.

17 recordsLinked to original sources

PubMed2006

Activation of EDTA-resistant gelatinases in malignant human tumors.

Among the many proteases associated with human cancer, seprase or fibroblast activation protein alpha, a type II transmembrane glycoprotein, has two types of EDTA-resistant protease activities: dipeptidyl peptidase and a 170-kDa gelatinase activity. To test if activation of gelatinases associated with seprase could be involved in malignant tumors, we used a mammalian expression system to generate a soluble recombinant seprase (r-seprase). In the presence of putative EDTA-sensitive activators, r-seprase was converted into 70- to 50-kDa shortened forms of seprase (s-seprase), which exhibited a 7-fold increase in gelatinase activity, whereas levels of dipeptidyl peptidase activity remained unchanged. In malignant human tumors, seprase is expressed predominantly in tumor cells as shown by in situ hybridization and immunohistochemistry. Proteins purified from experimental xenografts and malignant tumors using antibody- or lectin-affinity columns in the presence of 5 mmol/L EDTA were assayed for seprase activation in vivo. Seprase expression and activation occur most prevalently in ovarian carcinoma but were also detected in four other malignant tumor types, including adenocarcinoma of the colon and stomach, invasive ductal carcinoma of the breast, and malignant melanoma. Together, these data show that, in malignant tumors, seprase is proteolytically activated to confer its substrate specificity in collagen proteolysis and tumor invasion.

Animals↗

PubMed2006

Effects of G-CSF on cardiac remodeling and arterial hyperplasia in rats.

Although granulocyte colony-stimulating factor (G-CSF) has been shown to prevent cardiac remodeling after acute myocardial infarction, the mechanism and safety of G-CSF treatment acute myocardial infarction remain controversial. The purpose of the present study was to investigate in a rat model the mechanisms underlying the beneficial effect of G-CSF in acute myocardial infarction and to determine whether G-CSF treatment aggravates vascular remodeling of injured artery after acute myocardial infarction. Sprague-Dawley rats received transplanted bone marrow cells from green fluorescent protein (GFP) transgenic rats. Acute myocardial infarction was induced by ligation of the left coronary artery. After 24 h, the right carotid artery was injured with a balloon catheter. G-CSF (100 microg/kg/day) or saline was injected subcutaneously for 5 consecutive days after induction of acute myocardial infarction. G-CSF treatment significantly improved left ventricle function and reduced infarct size in rats with acute myocardial infarction. Expression of mRNA for the angiogenic cytokines was significantly higher in the infarction border area in the G-CSF group than in the control group. The surviving cardiomyocytes in infarction area were more in the G-CSF group. GFP-positive cells were gathered in the infarction border area in both groups; G-CSF did not increase cardiac homing of GFP-positive bone marrow cells in contrast to control group. Most GFP-positive cells were CD68-positive (macrophages). It was difficult to find bone marrow-derived cardiomyocytes in the infarcted area. G-CSF treatment inhibited neointima formation and increased reendothelialization of the injured artery. GFP-positive cells were identified most in the adventitia of the injured artery. A few cells in the neointima and reendothelialization were GFP positive. In conclusion, administration of G-CSF appears to be effective for treatment of left ventricular remodeling after acute myocardial infarction and does not aggravate vascular remodeling. The effect of G-CSF on cardiac and vascular remodeling may occur mainly through a direct action on the heart and arteries.

Actins↗

PubMed2006

Repetitive fluctuations in blood glucose enhance monocyte adhesion to the endothelium of rat thoracic aorta.

BACKGROUND: The aim of this study was to elucidate the effect of repetitive fluctuations in blood glucose concentrations on monocyte adhesion to the aortic endothelium. METHODS AND RESULTS: Nonobese type 2 diabetes, Goto-Kakizaki (GK) rats were fed twice daily to induce repetitive postprandial glucose spikes. Then, we compared the number of monocytes adherent to the endothelium of thoracic aorta in these rats with that in rats fed ad libitum. To suppress the glucose spikes, rats were injected with an inhibitor of sodium-glucose transporter, phloridzin, just before each meal for 12 weeks. GK rats fed twice daily showed significantly lower HbA1c than GK rats fed ad libitum. However, the former group showed markedly higher number of monocytes adherent to the endothelium than the latter, together with increased arterial intimal thickening. Phloridzin significantly reduced the number of adherent monocytes in GK rats fed twice daily. CONCLUSIONS: Our data demonstrated that repetitive postprandial fluctuation in glucose concentration evokes monocyte adhesion to endothelial cells that was worse than that induced by stable hyperglycemia in vivo. Suppression of such fluctuations efficiently suppressed monocyte adhesion to the aortic endothelium.

Animals↗

PubMed2006

[A study on diffuse alveolar damage and ubiquitin-positive pneumocytes in the elderly].

AIM: The ubiquitin proteasome system (UPS) is important because homeostasis through proteolysis and ubiquitin (Ub) has been observed to appear in diseases of the central nervous system. However, studies on UPS in relation to pulmonary diseases are few and no other investigators have described Ub-positive cells in the lung. Intracytoplasmic eosinophilic inclusion bodies in pneumocytes have been known to appear in cases of diffuse alveolar damage (DAD). We found that these inclusion bodies in DAD were positive for Ub. In this study, DAD cases in the elderly were studied to clarify the relationship between Ub-positive cells and cellular damage in the lungs. METHODS: Representative lung fields from a total of 26 patients with DAD were studied immunohistochemically, using Ub staining. The severity of DAD was evaluated after each case was scored for hyaline membrane formation and lung injury, respectively. Non-DAD diseases from 19 autopsy cases were studied as controls. The mean age of both groups was 72.1. RESULTS: Variably sized and shaped eosinophilic inclusion bodies were found in 7 cases (26.9%) of the DAD cases (inclusion body group) and all inclusion bodies were positive for Ub and cytokeratin KL-1. Pneumocytes without inclusion bodies were occasionally positive for Ub, with an intracytoplasmic granular pattern, not only in the inclusion body group but also in the non-inclusion body group (4 of DAD cases). These Ub-positive cells (both Ub-positive inclusion bodies and the granular Ub-positive cells) were found to have high rate of hyaline membrane formation and lung injury in the DAD cases. CONCLUSION: Elderly DAD cases had Ub-positive inclusion bodies in pneumocytes and Ub-positive pneumocytes were found with or without the inclusion bodies in DAD. This means that accumulation of ubiquitinated protein including cytokeratin could be recognized as inclusion bodies in pneumocytes. The presence of these Ub-positive cells might be a morphological indicator for evaluation of cellular damage in the patients with DAD.

Aged↗

PubMed2005

A strategy of retrograde injection of bone marrow mononuclear cells into the myocardium for the treatment of ischemic heart disease.

OBJECTIVE: Bone marrow cells implantation (BMI) has been reported to efficiently improve ischemic heart disease. However, BMI strategies are generally invasive. To establish a BMI strategy for ischemic heart disease, we performed implantation of autologous cryopreserved mononuclear cells (MNCs) from bone marrow (BM) retrogradely into the myocardium via the coronary vein in pigs with acute myocardial infarction (AMI) and old myocardial infarction (OMI). METHODS: BM cells were harvested from the pigs' fumurs. MNCs were collected by centrifugation and were cryopreserved. Anterior myocardial infarction was induced by occlusion of the midportion of the left anterior descending coronary artery without surgical intervention. Frozen BM cells were quickly thawed and injected retrogradely via the coronary vein into the myocardium through a single balloon infusion catheter 6 h and 2 weeks after the induction of infarction. Four weeks after implantation, coronary arteriograms were obtained, cardiac function was analyzed with the use of a conductance catheter, and histopathologic analysis was performed with a confocal laser microscope. Plasma levels of natriuretic peptides and angiogenic growth factors were measured after BMI. RESULTS: Flow cytometric analysis revealed that 90% of cryopreserved BM cells were viable in vitro. Labeled BM cells were entirely distributed around in the infarcted area of maycardium in pigs. BMI increased collateral neovascuralization in infarcted hearts. BMI significantly improved cardiac function in AMI with BMI and OMI with BMI groups. BMI also increased the formation of microcapillary arteries in infarcted hearts. Levels of natriuretic peptides were significantly decreased, and levels of vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (FGF2) were significantly increased after BMI. Confocal laser microscopy revealed the presence of proliferative and activated myocardial cells in infarcted hearts after BMI. CONCLUSION: The retrograde infusion of cryopreserved BM cells into myocardium efficiently induced angiogenesis and improved cardiac function in pigs with AMI or OMI. These results suggest that the present strategy of BMI will be safe and feasible as an angiogenic cell therapy for ischemic heart disease.

Animals↗

PubMed2005

A fatal case of ruptured giant coronary artery aneurysm.

A 5-year-old Japanese boy died because of a ruptured left coronary artery aneurysm (CAA). He was diagnosed as having Kawasaki disease (KD) on the 5th day from onset, with all of the principal signs. On the 7th day of illness, bilateral CAAs were already found via echocardiography, and he was treated with intravenous (IV) gamma globulin and oral ASA. However, the fever persisted and the CAA progressed rapidly. Echocardiography on the 12th illness day showed a giant (18-mm) left anterior descending (LAD) artery aneurysm. Oral propranolol and nifedipine were administered, in conjunction with warfarin/aspirin anti-coagulation therapy. On the 13th day of illness, cardiac arrest developed abruptly, and, despite cardiopulmonary resuscitation (CPR), the patient remained unresponsive and died one hour later. The final pathological diagnosis was a ruptured LAD artery aneurysm and cardiac tamponade. Microscopic investigation of the ruptured vascular wall revealed marked neutrophilic infiltration, with fewer macrophages and lymphocytes. CAA ruptures are a very rare, but fatal, complication of KD. Based on a review of previous reports on CAA ruptures, we consider it useful to distinguish aneurysms which rapidly dilate and continue to expand beyond a diameter of 10 mm with ongoing vasculitis (these CAAs can be termed "super-giant") from the more common giant CAAs limited to a diameter of 8 or 9 mm, because a decision must be made as to whether to start intensive care or to intervene surgically, in order to ensure the survival of patients with such a potentially critical complication.

Aneurysm, Ruptured↗

PubMed2005

'Increased expression of seprase, a membrane-type serine protease, is associated with lymph node metastasis in human colorectal cancer'.

Seprase is a membrane-bound serine proteinase with gelatinase activity, which may be involved in cancer invasion and metastasis. We examined seprase expression in colorectal cancer specimens obtained from 109 patients. Seprase immunoreactivity was found in cancer cells and adjacent stromal cells. Immunoblotting showed higher levels of seprase protein in colorectal cancer tissue than in normal colorectal tissue. A semiquantitative assessment of the immunohistochemistry results revealed a significant correlation between seprase expression and lymph node metastasis. These results suggested that an abundant expression of seprase in colorectal cancer tissue is associated with lymph node metastasis.

Adult↗

PubMed2004

A lipid peroxidation-derived inflammatory mediator: identification of 4-hydroxy-2-nonenal as a potential inducer of cyclooxygenase-2 in macrophages.

Cyclooxygenases (COXs) catalyze the conversion of arachidonic acid to eicosanoids, which mediate a variety of biological actions involved in vascular pathophysiology. In the present study, we investigated the role of lipid peroxidation products in the up-regulation of COX-2, an inducible isoform responsible for high levels of prostaglandin production during inflammation and immune responses. COX-2 was found to colocalize with 4-hydroxy-2-nonenal (HNE), a major lipid peroxidation-derived aldehyde, in foamy macrophages within human atheromatous lesions, suggesting that COX-2 expression may be associated with the accumulation of lipid peroxidation products within macrophages. To test the hypothesis that lipid peroxidation products might be involved in the regulation of prostanoid biosynthesis, we conducted a screen of oxidized fatty acid metabolites and found that, among the compounds tested, only HNE showed inducibility of the COX-2 protein in RAW264.7 macrophages. In addition, intraperitoneal administration of HNE resulted in an increase in cell numbers in the peritoneal cavity that was associated with significant increases in the peritoneal and tissue levels of COX-2 in mice. To understand the possible signaling mechanism underlying the inducing effect of HNE on COX-2 up-regulation, we examined the phosphorylation events that may lead to COX-2 induction and found that HNE did not stimulate the induction of nitric oxide synthase and activation of NF-kappaB but significantly activated p38 mitogen-activated protein kinase and its upstream kinase in RAW264.7 macrophages. Tyrosine kinases, such as the epidermal growth factor-like and Src family tyrosine kinases, appeared to mediate the stabilization of COX-2 mRNA via the p38 mitogen-activated protein kinase pathway. These findings suggest that HNE accumulated in macrophages/foam cells may represent an inflammatory mediator that plays a role in stimulation of the inflammatory response and contributes to the progression of atherogenesis.

Aldehydes↗

PubMed2004

The expression of a type II transmembrane serine protease (Seprase) in human gastric carcinoma.

OBJECTIVE: The invasion and metastasis of carcinoma cells require the proteolytic degradation of the extracellular matrix by various cell surface proteases. Among these, seprase is a type II transmembrane serine protease absent in normal tissues and it has been implicated in the invasion of the extracellular matrix by both tumor and stromal cells in human breast carcinoma and melanoma. In the present study, the expression of seprase mRNA, protein and its gelatin-degrading activity in human gastric carcinoma were examined to substantiate the potential role of seprase in gastric carcinoma invasion. METHODS: We have examined the seprase expression in human gastric carcinoma (n = 34) by RT-PCR, Western immunoblotting analysis, immunohistochemistry, and gelatin zymography. RESULTS: Immunoblotting analysis using mAb D8 directed against seprase showed that the carcinoma tissues in 26 out of 34 cases of gastric cancer expressed a dimeric form of seprase but their normal counterparts did not. Gelatin zymography confirmed that the isolated seprase exhibited the gelatin-degrading activity and was active. Seprase-expressing carcinoma tissues were more often found in the scirrhous type than in other types of gastric carcinoma. RT-PCR analysis showed that seprase mRNA was present in carcinoma tissues but not in normal tissues. Immunohistochemically, seprase was mainly located in gastric carcinoma cells, weakly in stromal cells and microvessel endothelial cells in the tumor nest, and none in normal cells. CONCLUSIONS: Our studies showed the unique expression and localization of seprase in the tumor and stromal cells within human gastric carcinoma but not in normal tissues, suggesting a role of seprase in the invasive and metastatic progression of gastric carcinoma.

Biomarkers, Tumor↗

PubMed2004

[Atherosclerotic regression in the aortas of elderly. (4). Expression of peroxisome proliferator-activated receptors with references of centrally depressed atherosclerotic plaque].

Peroxisome proliferator-activated receptors (PPARs) play an important role in vascular events during progression of atherosclerosis, associated with lipid metabolism, inflammatory response and others. To clarify relationships between the expression of PPARs subtypes and regression, we studied mRNA expression of PPARs subtypes with reverse transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry, especially in centrally depressed atherosclerotic plaques (depressed plaque) in the aortas of elderly patients, and proposed morphological feature of atherosclerotic regression. Samples were separated from the depressed plaque, atheromatous plaque, and diffuse intimal thickening (DIT) in the aortas of elderly patients at autopsy and they were analyzed for RT-PCR. The depressed plaques obtained were divided into two parts: depressed area and surrounding elevated area. Total RNA was prepared, using the TRIzol Reagent, and was reverse transcribed using random hexamer primers and Thermoscript kit for RT-PCR. Immunohistochemical analysis was processed for mouse anti-PPAR gamma antibody, detected by the ABC method. 1) Decreased foam cells were found in the depressed area than in the surrounding elevated area of the depressed plaque. These foam cells were immunohistochemically positive for HAM56 and strong reactivities for PPAR gamma were found in the nuclei of macrophage-derived foam cells. PPAR gamma was also detected in the nuclei of endothelial cells and smooth muscle cells. 2) Expressions of PPAR alpha and PPAR gamma were found in the depressed plaques with RT-PCR. These expressions were found both in the depressed area and the surrounding elevated area without significant differences. 3) PPAR gamma mRNA expression both in the depressed area and the surrounding elevated area, was greater than in DIT, and was less than in the atheromatous plaque. 4) Expression of PPAR gamma mRNA was intense and increased in the surrounding elevated area than in the depressed area. 5) A significant increase of PPAR gamma expression was found in the atheromatous plaque than in the DIT. 6) There was no significant difference of PPAR alpha mRNA expression between the depressed area and the surrounding elevated area. The depressed plaque has been considered to be a morphological characteristic of regression in recent studies. Expression of mRNA for PPARs was detected in the depressed plaque as well as the atheromatous plaque, furthermore, there were different expressions and intensity of PPARs between the depressed area and the surrounding elevated area of the depressed plaque. These findings suggest that the expression of PPARs may be involved not only in the progression of atherosclerosis but also in regression.

Adult↗

PubMed2003

A new En face method is useful to quantitate endothelial damage in vivo.

Endothelial damage is considered to be an initial change in the atherosclerotic process. However, it has been difficult to detect this initial change in vivo. We established a modified En face immunostaining method that enabled us to obtain clear images of the entire endothelial surface, including at arterial bifurcations, and to quantitate the number of cells of interest in the endothelium. Using this method, we found that treatment with an atherogenic factor, albumin-derived advanced glycosylation end products, for only 2 weeks caused a significant increase in the number of proliferating cell nuclear antigen-positive endothelial cells and the number of macrophages adhering to the endothelium, suggesting that these changes might be relevant to the early events of endothelial dysfunction. In conclusion, the present modified En face immunostaining method may be a promising tool for understanding the pathophysiology of atherosclerosis.

Animals↗

PubMed2003

Increased expression of seprase, a membrane-type serine protease, is associated with lymph node metastasis in human colorectal cancer.

Adult↗

PubMed2003

Shear stress-induced collagen XII expression is associated with atherogenesis.

Fluid shear stress has been shown to modulate various endothelial functions. We selected a shear stress-specific clone, identified as collagen XII, from a bovine aortic endothelial cell (BAEC) cDNA library. We confirmed that shear stress induces collagen XII expression at both the mRNA and protein levels in cultured BAECs and human umbilical vein ECs (HUVECs) by stimulating transcription. When HUVECs were exposed to shear stress, they secreted collagen XII protein and it was deposited underneath them. Strong expression of collagen XII was found in the intima of human aortic wall lacking atherosclerotic lesions, whereas weak expression was seen in the intima of atherosclerotic plagues. Furthermore, the downstream portion of atherosclerotic plaques showed apparently weak collagen XII expression compared with the upstream portion. These results suggest that collagen XII expression induced by fluid shear stress may play a role in stabilizing the vascular structure and preventing the formation of atherosclerotic lesions.

Animals↗

PubMed2003

Seprase, a membrane-type serine protease, has different expression patterns in intestinal- and diffuse-type gastric cancer.

OBJECTIVE: Seprase is an integral membrane serine proteinase with gelatinase activity that may be involved in cancer invasion and metastasis. However, the pathophysiologic significance of its expression in gastric cancer tissue has not been fully elucidated. METHODS: Seprase expression and distribution in gastric cancer specimens obtained from 133 patients were examined by immunohistochemistry and immunoblotting. RESULTS: Immunohistochemistry showed that in intestinal-type cancer, which includes well and moderately differentiated adenocarcinoma, seprase immunoreactivity was mainly recognized in the moderately differentiated cells and not in the well differentiated cells. In the diffuse type, which includes poorly differentiated adenocarcinoma and signet ring cell carcinoma, seprase immunoreactivity was seen mainly in cells with poor cell-to-cell junctions. The reactive pattern in the cells was different between moderately differentiated adenocarcinoma and diffuse-type carcinoma. Besides the cytoplasm, the cell membrane also apparently reacted in the former, while only the cytoplasm reacted diffusely in the latter. Seprase immunoreactivity was also recognized in endothelial cells and stromal cells especially adjacent to tumor nests. The immunoreactivity of the stromal cells was more abundant in the intestinal type than in the diffuse type, and these stromal expressions of seprase in the intestinal type correlated with the liver (13/13 = 100% of cases with metastases) or lymph node metastases (33/34 = 97% of cases with metastases). Immunoblotting showed that the levels of seprase protein were higher in intestinal-type cancer than in diffuse-type cancer. CONCLUSION: These results suggested that there is a difference in seprase expression between intestinal- and diffuse-type gastric cancer; this difference may reflect distinct biological features of these types of cancer.

Aged↗

PubMed2002

Induction of human inhibitor of apoptosis protein-2 by shear stress in endothelial cells.

To disclose the anti-atherosclerotic mechanisms of steady laminar shear stress, we analyzed the expression of human inhibitor of apoptosis protein-2 (HIAP-2), whose gene was selected from a cDNA library of sheared endothelial cells (ECs), on ECs. HIAP-2 was dose-independently and time-dependently induced in ECs by shear stress, regulated at the transcriptional level. HIAP-2 expression was also identified in vivo. Shear stress-mediated inhibition of EC apoptosis was associated with the inhibition of caspase-3 activity, suggesting that the shear stress prevents EC apoptosis via negative regulation of caspase-3 by the increment of HIAP-2.

Animals↗

PubMed2002

Effects of Lentinus edodes mycelia on dietary-induced atherosclerotic involvement in rabbit aorta.

Lentinus edodes mycelia lowers cholesterol levels and acts as an immunomodulator and tumor-inhibitor in animal models. Lentinus edodes mycelia contains eritadenine (C(9)H(11)O(4)N(5)) and glucans among other biological compounds. However, whether or not Lentinus edodes mycelia is anti-atherogenic remains unknown. We examined the effect of Lentinus edodes mycelia (L.E.M) on atherosclerosis in a rabbit model. Thirty-two Japanese white male rabbits were fed with 1.0% cholesterol for 8 weeks, then divided into groups and given 1) 1.0% cholesterol for over 8 weeks (control), 2) 1.0% cholesterol and 1.0% L.E.M for over 8 weeks, 3) 1.0% cholesterol and 2.0% L.E.M for over 8 weeks, and 4) 1.0% cholesterol and 4.0% L.E.M for over 8 weeks (n=8 each group). Total cholesterol (TC) was measured periodically throughout the experiment. After the experimental periods, the aortas were removed and atherosclerotic lesions were examined histologically, immunohistochemically and morphometrically to determine surface involvement (SI) and an atherosclerotic index (AI). Body weight and TC did not significantly differ among the four groups. Decreases in SI were significant in the 1% L.E.M (26.2+/-10.8%) and 2% L.E.M (29.3+/-15.7%) groups compared with the control (48.7+/-15.3%; p < 0.05). The AI was significantly decreased in the 1% L.E.M (6.62+/-4.31) and 2% L.E.M (7.49+/-3.49) groups compared with the control (16.96+/-9.21; p < 0.05). Foam cells aggregated in thickened intima of dietary-induced atherosclerotic lesions in the rabbit aorta. In contrast, the numbers of foam cells in the intima decreased in the experimental group. No-cholesterol-lowering action or dose-dependant effects of L.E.M were determined in this study, but atherosclerotic development was significantly inhibited, indicating that L.E.M had anti-atherogenic properties. L.E.M may inhibit atherosclerotic development in rabbit aorta and be beneficial as a nutritional supplement.

Animals↗

PubMedDate not supplied

Expression patterns of seprase, a membrane serine protease, in cervical carcinoma and cervical intraepithelial neoplasm.

BACKGROUND: Seprase is a membrane-bound serine proteinase with gelatinase activity, which may be involved in cancer invasion and metastasis. PATIENTS AND METHODS: We examined the seprase expression patterns in invasive or preinvasive squamous epithelial lesions. RESULTS AND CONCLUSION: No seprase immunoreactivity was found in the atypical epithelial cells and subepithelial stromal cells of CIN1 and 2 lesions. No seprase expression could be detected even in CIN3 lesions. However, in contrast to CIN1 and 2, seprase immunoreactivity was occasionally observed in the subepithelial stromal cells that were associated with moderate or severe inflammatory infiltrates. Some microinvasive carcinomas and all invasive carcinomas showed seprase immunoreactivity in the cancer cells with various degrees of seprase-positive stromal cells. Seprase may be an early marker of tumor invasion in squamous lesions of the uterine cervix.

Adult↗