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Biomedical subjects

U Ikeda

Publications and source records attributed to U Ikeda.

At least 55 records · Page 3Linked to original sources
PubMed2000

Assessment of coagulation and platelet activation in coronary sinus blood induced by transcatheter coronary intervention for narrowing of the left anterior descending coronary artery.

Influences of recently developed methods for coronary intervention on hemostasis in the coronary circulation are unclear. The objective of this study was to investigate changes in coagulation and platelet activation in the coronary circulation induced by percutaneous transluminal coronary angioplasty (PTCA). We studied 35 patients with coronary heart disease who underwent elective PTCA to isolated stenotic narrowing of left coronary arteries. Seven patients received only PTCA, 12 underwent percutaneous transluminal rotational atherectomy (PTRA), and 16 underwent stent implantation. Blood samples were drawn from the coronary sinus immediately before and after as well as 4 and 24 hours after PTCA. Plasma levels of tissue factor (TF), thrombin-antithrombin III complex, plasminogen activator inhibitor (PAI)-1, tissue plasminogen activator (t-PA), beta-thromboglobulin, and platelet factor 4 were measured by enzyme-linked immunosorbent assay. In all patients, TF levels in the coronary sinus blood showed significant increases 4 and 24 hours after PTCA and thrombin-antithrombin III complex levels showed significant increases 24 hours after PTCA. PAI-1 showed significant increases 24 hours after PTCA and t-PA showed significant increases 4 and 24 hours after PTCA. Changes in levels of these markers by PTCA were similar among the 3 groups. In PTRA, levels of beta-thromboglobulin and platelet factor 4, markers of platelet activation, increased immediately after the procedure and returned to baseline levels after 4 hours. PTCA induced increases in blood coagulation and fibrinolysis in the coronary circulation. PTRA caused a marked but transient activation of platelets. These changes may contribute to acute complications during the procedure.

Adult↗
PubMed2000

Release of endothelin 1 and angiotensin II induced by percutaneous transluminal coronary angioplasty.

Endothelial injury plays critical roles in acute and chronic complications after percutaneous transluminal coronary angioplasty (PTCA). We investigated coronary endothelial injury and the release of vasoactive substances induced by PTCA. We examined 44 patients with ischemic heart disease who underwent elective PTCA to isolated stenotic lesions in left coronary arteries. Eleven patients received balloon angioplasty (BA), 14 percutaneous transluminal rotational atherectomy (PTRA), and 19 stent implantation. Blood samples were drawn from the coronary sinus immediately before and after as well as 4 hr and 24 hr after PTCA. Plasma levels of endothelin (ET) 1, angiotensin (ANG) II, von Willebrand factor (vWF), and thrombomodulin (TM) were measured. Seven control subjects who underwent diagnostic coronary angiography (CAG) were used as controls. In all patients, ET-1 levels in the coronary sinus blood significantly increased immediately after PTCA. ANG II levels and vWF activity showed significant increases 4 hr after PTCA. Changes in levels of these markers were similar among the BA, PTRA, and stent groups. TM levels were elevated in all groups of patients, including those simply undergoing diagnostic CAG. Changes in ET-1, ANG II, and vWF levels in the coronary sinus reflect coronary endothelial injury induced by PTCA.

Aged↗
PubMed2000

Carvedilol stimulates nitric oxide synthesis in rat cardiac myocytes.

The purpose of this study was to investigate the effects of the beta-adrenergic blocker carvedilol on nitric oxide (NO) synthesis in cardiac myocytes. We measured the accumulation of nitrite, a stable oxidation product of NO, and the expression of inducible NO synthase (iNOS) protein in cultured neonatal rat cardiac myocytes. Incubation of the cultures with interleukin 1 beta (IL-1 beta; 10 ng/ml) caused a marked increase in nitrite production. Although carvedilol alone showed no effect on nitrite accumulation, it significantly enhanced IL-1 beta-induced nitrite production by cardiac myocytes. The effect of carvedilol was completely abolished in the presence of aminoguanidine or actinomycin D. The nitrite production enhanced by carvedilol was accompanied by increased iNOS protein expression. Unlike carvedilol, other beta-blockers, namely propranolol, atenolol and arotinolol, did not enhance IL-1 beta-induced nitrite production. Addition of isoproterenol significantly increased nitrite production by IL-1 beta-stimulated cardiac myocytes. Atenolol suppressed this isoproterenol-induced nitrite accumulation, while carvedilol further increased the nitrite accumulation. These findings indicate that carvedilol increases NO synthesis in IL-1 beta-stimulated rat cardiac myocytes by a beta-adrenoceptor-independent mechanism.

Adrenergic beta-Agonists↗
PubMed2000

Matrix metalloproteinase-1 expression by interaction between monocytes and vascular endothelial cells.

There is accumulating evidence of complicated interactions among vascular cells, i.e. endothelial cells, smooth muscle cells and monocytes/macrophages, in the regulation of vascular function and remodeling. We have investigated the mechanisms responsible for matrix metalloproteinase (MMP)-1 expression by interactions between monocytes and vascular endothelial cells. THP-1 cells (human monocytic cell line) and human umbilical vein endothelial cells (HUVECs) were cocultured. MMP-1 levels in the culture medium were measured by enzyme-linked immunosorbent assays. Collagenolytic activity in the culture medium was measured by fluorescence labeled-collagen digestion. Immunohistochemistry using an anti-MMP antibody was carried out to determine which types of cell produce MMP-1. The addition of THP-1 cells to HUVECs for 48 h induced increases in MMP-1 levels and collagenolytic activity, which were 5- and 2-fold relative to those of HUVECs alone, respectively. A separate coculture experiment revealed that direct contact of THP-1 cells and HUVECs contributed to enhanced MMP-1 production in the cocolture. Immunohistochemical analysis revealed that both types of cell produce MMP-1 in the coculture. Neutralizing anti-interleukin-1 beta and tumor necrosis factor- alpha antibodies inhibited MMP-1 production by the coculture. The Src kinase and MEK inhibitors significantly inhibited MMP-1 production by the coculture. Coculture of THP-1 cells and HUVECs induced significant increases in Src and mitogen activated protein (MAP) kinase activities. Enhanced MMP-1 expression induced by monocyte-endothelial cell interactions may play an important role in the pathogenesis of atherosclerosis and plaque rupture.

Arteriosclerosis↗
PubMed2000

Interaction between human monocytes and vascular smooth muscle cells induces vascular endothelial growth factor expression.

The objective of this study was to investigate whether synthesis of vascular endothelial growth factor (VEGF), a major mitogen for vascular endothelial cells, was induced by a cell-to-cell interaction between monocytes and vascular smooth muscle cells (VSMCs). Human VSMCs and THP-1 cells (human monocytoid cell) were cocultured. VEGF levels in the coculture medium were determined by enzyme-linked immunosorbent assay. Northern blot analysis of VEGF mRNA was performed using a specific cDNA probe. Immunohistochemistry was performed to determine which types of cell produce VEGF. Adding THP-1 cells to VSMCs for 24 h increased VEGF levels of the culture media, 8- and 10-fold relative to those of THP-1 cells and VSMCs alone, respectively. Northern blot analysis showed that VEGF mRNA expression was induced in the cocultured cells and peaked after 12 h. Immunohistochemistry disclosed that both types of cell in the coculture produced VEGF. Separate coculture experiments revealed that both direct contact and a soluble factor(s) contributed to VEGF production. Neutralizing anti-interleukin (IL)-6 antibody inhibited VEGF production by the coculture of THP-1 cells and VSMCs. A cell-to-cell interaction between monocytes and VSMCs induced VEGF synthesis in both types of cell. An IL-6 mediated mechanism is at least partially involved in VEGF production by the cocultures. Local VEGF production induced by a monocyte-VSMC interaction may play an important role in atherosclerosis and vascular remodeling.

Blotting, Northern↗
PubMed2000

Amlodipine increases nitric oxide synthesis in cytokine-stimulated cultured vascualar smooth muscle cells.

OBJECTIVE: If calcium channel blockers affect nitric oxide synthesis in the vascular tissue, they could influence disease progression in coronary arteries. We investigated the effects of the calcium channel blocker amlodipine on nitric oxide synthesis by measuring the production of nitrite, a stable metabolite of nitric oxide, in vascular smooth muscle cells. METHODS: We measured the production of nitrate in cultured rat vascular smooth muscle cells with the Griess reagent Inducible nitric oxide synthase protein and mRNA expression were assayed by Western blotting and reverse transcription-polymerase chain reaction, respectively. The levels of NF-kappaB proteins in nuclear extracts were analyzed by gel retardation assay. RESULTS: Incubation of cultures with interleukin-1 , (10 ng/ ml) for 24 h caused a significant increase in nitrite generation. Interleukin-1 l-induced nitrite production by vascular smooth muscle cells was significantly increased by amlodipine in a dose-dependent manner. This augmentative effect of amlodipine was completely abolished in the presence of N(G)-monomethyl-L-arginine or actinomycin D. Amlodipine-induced nitrite production was accompanied by increased inducible nitric oxide synthase mRNA and protein accumulation. Interleukin-1 , induced NF-kappaB activation in vascular smooth muscle cells, and addition of amlodipine further increased this NF-kappaB activation. The effect of amlodipine on nitrite production was maintained in the presence of the calcium channel agonist Bay K 8644. CONCLUSION: Amlodipine enhances nitric oxide synthesis in cytokine-stimulated cultured vascular smooth muscle cells by L-type calcium channel-independent mechanisms.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed2000

Interaction between monocytes and vascular smooth muscle cells induces expression of hepatocyte growth factor.

OBJECTIVE: To investigate the expression of hepatocyte growth factor (HGF)--a multifunctional factor implicated in tissue regeneration, wound healing and angiogenesis--that is induced by cell-to-cell interactions between monocytes and vascular smooth muscle cells (VSMCs), using coculture of human VSMCs and cells of the human monocytoid cell line, THP-1. METHODS: We collected supernatant from the coculture medium and measured HGF concentrations with an enzyme-linked immunosorbent assay. Northern blot analysis of HGF mRNA was performed using a specific cDNA. To explore which types of cells produce HGF, we performed immunohistochemistry. RESULTS: Coculture of VSMCs with THP-1 cells for 24 h caused a fivefold increase in HGF concentrations over that in control VSMC culture. Northern blot analysis showed an induction of HGF mRNA in the coculture with a peak at 3 h. Separated cocultures demonstrated that both direct contact and soluble factors contribute to the production of HGF. Immunohistochemistry demonstrated that both types of cells in the coculture produce HGF. Neutralizing antibodies against tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6 inhibited the HGF production in THP-1 cells and VSMCs that was induced by the coculture conditioned medium. The protein kinase C inhibitors H-7, calphostin C and K252b, and the tyrosine kinase inhibitor, genistein, significantly inhibited the production of HGF in the coculture. CONCLUSIONS: Cell-to-cell interactions between monocytes and VSMCs induced HGF synthesis in both types of cells, suggesting that local HGF production induced by this cell-to-cell interaction has an important role in the pathogenesis of hypertension, atherosclerosis or vascular remodelling.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2000

Amlodipine inhibits expression of matrix metalloproteinase-1 and its inhibitor in human vascular endothelial cells.

Matrix metalloproteinase-1 (MMP-1) may play an important role in the pathogenesis of atherosclerosis and atherosclerotic plaque rupture. We investigated the effect of the calcium channel blockers amlodipine and nifedipine on the expression of MMP-1 and tissue inhibitor of metalloproteinase-1 (TIMP-1) in endothelial cells (ECs). MMP-1 and TIMP-1 levels in conditioned media of human vascular ECs were measured by enzyme-linked immunosorbent assay. Collagenolytic activity was determined by fluorescence-labeled collagen digestion. The addition of interleukin-1beta (IL-1beta) increased MMP-1 levels in the culture media of ECs. Amlodipine, but not nifedipine, significantly decreased MMP-1 levels in IL-1beta-stimulated ECs. TIMP-1 levels also were significantly increased by IL-1beta, and its expression was slightly decreased by amlodipine, not by nifedipine. Amlodipine significantly inhibited collagenolytic activity in the culture media of IL-1beta-stimulated ECs, whereas nifedipine showed no significant effect on the activity. Our findings revealed that amlodipine, but not nifedipine, inhibits IL-1beta-induced MMP-1 expression in human ECs.

Amlodipine↗
PubMed2000

Interaction between monocytes and vascular smooth muscle cells enhances matrix metalloproteinase-1 production.

Matrix metalloproteinase-1 (MMP-1) plays an important role in atherosclerotic plaque rupture. The purpose of this study was to investigate the expression of MMP-1 by cell-to-cell interactions between monocytes and vascular smooth muscle cells (VSMCs). Human VSMCs and THP-1 cells (human monocytoid cells) were cocultured. MMP-1 levels were measured by enzyme-linked immunosorbent assay. Collagenolytic activity was determined by fluorescent labeled-collagen digestion. Immunohistochemistry was performed to determine which types of cells produce MMP-1. Adding THP-1 cells to VSMCs markedly increased the MMP-1 levels and activity of the culture media. MMP-1 levels were maximal when the cellular ratio of THP-1 cells/VSMCs was 1.0. Immunohistochemistry revealed that both types of cells in the coculture produced MMP-1. Separated coculture experiments showed that both direct contact and a soluble factor(s) contributed to MMP-1 production. Neutralizing anti-interleukin (IL)-6 and tumor necrosis factor-alpha antibodies inhibited coculture conditioned medium-induced MMP-1 production by VSMCs and THP-1 cells. Protein kinase C inhibitors, tyrosine kinase inhibitors, and a mitogen-activated protein kinase inhibitor significantly inhibited MMP-1 production by cocultures. Direct cell-to-cell interaction between THP-1 cells and VSMCs enhanced MMP-1 synthesis in both types of cells. Increased local MMP-1 production and activity induced by monocyte-VSMC interaction play an important pathogenic role in atherosclerotic plaque rupture.

Cell Adhesion↗
PubMed2000

Adeno-associated virus-mediated vascular endothelial growth factor gene transfer into cardiac myocytes.

Vascular endothelial growth factor (VEGF) is an angiogenic growth factor that stimulates endothelial cell proliferation, increases endothelial permeability, and promotes collateral vessel formation. We transferred human VEGF gene into rat cardiac myocytes using adeno-associated virus (AAV) vectors and investigated whether VEGF secreted from the transduced cardiac myocytes promoted proliferation of endothelial cells. We produced VEGF-expressing AAV vectors (AAV-VEGF) by the adenovirus-free method. Immunoblotting revealed VEGF protein expression in AAV-VEGF-transduced rat cardiac myocytes. More than 60% of cardiac myocytes were stained positively on immunohistochemical staining using anti-VEGF antibody. Concentration of VEGF in the culture medium of AAV-VEGF-transduced myocytes was increased in a vector dose-dependent manner, and VEGF secretion from the transduced myocytes persisted for > or = 14 days. Thymidine incorporation into human vascular endothelial cells was significantly increased by incubation with the conditioned medium from AAV-VEGF-transduced myocytes. This increased thymidine uptake was significantly inhibited by anti-VEGF antibody. We demonstrated here that AAV-mediated VEGF gene transfer into cardiac myocytes induces the secretion of functional VEGF.

Animals↗
PubMed2000

Inhibition of vascular endothelial growth factor activity by transfection with the soluble FLT-1 gene.

Vascular endothelial growth factor (VEGF)-induced angiogenesis is involved in the etiology of some cardiovascular diseases. The soluble form of VEGF receptor, FLT-1 (sFLT-1), is a potent antagonist of VEGF. Therefore, we investigated whether transfection with the sFLT-1 gene could inhibit VEGF-induced angiogenesis. Human embryonic kidney (HEK)-293 cells were transfected with plasmids containing VEGF and sFLT-1 (pCMV-VEGF and pCMV-sFLT-1) by the calcium-phosphate co-precipitation method. VEGF- and/or sFLT-1-transfected HEK-293 cells were incubated for 24 h, and then conditioned medium was collected. The effects of conditioned medium on angiogenesis were tested by incorporation of [3H]thymidine into human umbilical vein endothelial cells (HUVECs). Expression of VEGF protein was determined by Western blotting. The conditioned medium from sFLT-1 gene-transfected HEK-293 cells significantly inhibited recombinant VEGF-induced increase in [3H]thymidine incorporation by HUVECs. VEGF gene-transfected HEK-293 cells secreted VEGF protein into conditioned medium. This conditioned medium increased [3H]thymidine incorporation by HUVECs, which was significantly inhibited by co-transfection of sFLT-1 gene with VEGF gene. These observations suggested that sFLT-1 gene transfer could inhibit VEGF-induced DNA synthesis of vascular endothelial cells.

Blotting, Western↗
PubMed2000

Production of hepatocyte growth factor during acute myocardial infarction.

OBJECTIVE: To investigate the clinical significance of circulating hepatocyte growth factor (HGF) and the role of peripheral blood mononuclear cells (monocytes), which are a possible source of HGF, in patients with acute myocardial infarction. DESIGN AND PATIENTS: 37 patients with acute myocardial infarction and 13 normal control subjects were recruited. Peripheral venous blood samples were drawn from the infarct patients 1, 7, 14, and 21 days after onset. Monocytes were isolated from peripheral blood at those times. HGF concentrations in serum and in a culture medium of monocytes after incubation for 24 hours (monocyte HGF levels) were measured by enzyme linked immunosorbent assay. RESULTS: Serum HGF and monocyte HGF values within seven days after onset of myocardial infarction were significantly higher than those of control subjects and decreased by day 14. There were significant positive correlations between serum HGF and monocyte HGF levels on day 7; between maximum plasma creatine phosphokinase levels and serum HGF levels on day 1; between maximum plasma C reactive protein and serum HGF levels; and between maximum C reactive protein and monocyte HGF levels. Monocyte HGF levels were raised in the patients with progression of ventricular enlargement in the course of acute myocardial infarction. CONCLUSIONS: Early serum HGF concentrations reflect the extent of myocardial damage in acute myocardial infarction patients. Inflammation after acute myocardial infarction is supposed to be involved in enhanced HGF production. Monocytes may play an important role in ventricular remodelling after acute myocardial infarction by releasing the cardiovascular protective mitogen HGF.

Adult↗
PubMed2000

Inhibition of angiotensin converting enzyme cannot prevent increases in angiotensin II production in coronary circulation.

OBJECTIVE: To determine whether inhibition of angiotensin converting enzyme (ACE) can prevent angiotensin II production in the coronary circulation induced by percutaneous transluminal coronary angioplasty (PTCA) in patients with myocardial ischaemia. DESIGN, PATIENTS: 41 patients who underwent elective PTCA and six control subjects who received diagnostic coronary angiography were studied. Patients were divided into two groups according to the chronic administration of ACE inhibitors (group A, 15 patients treated with ACE inhibitors; group B, 26 patients without ACE inhibitors). Blood samples were drawn through catheters placed in the aorta and coronary sinus before and 24 hours after PTCA. RESULTS: Mean levels of ACE activity in the aorta were significantly lower in patients in group A than in group B. However, mean angiotensin II concentrations in the aorta were not significantly different between the two groups. Differences in basal angiotensin II concentrations between the coronary sinus and aorta, which reflected basal angiotensin II production in the coronary circulation, were not significant among group A, group B, and control subjects. The production of angiotensin II in the coronary circulation was significantly increased 24 hours after PTCA in both group A and group B to the same extent. No significant changes were observed in control subjects 24 hours after diagnostic coronary angiography. CONCLUSIONS: This study revealed that inhibition of ACE activity by ACE inhibitors could not prevent increases in angiotensin II production in the coronary circulation induced by PTCA.

Adult↗
PubMed2000

Interleukin 6 expression in coronary circulation after coronary angioplasty as a risk factor for restenosis.

OBJECTIVE: To investigate changes in cytokine expression in the coronary circulation induced by percutaneous transluminal coronary angioplasty (PTCA). METHODS: The study involved 32 patients with ischaemic heart disease who underwent elective PTCA for isolated stenotic lesions of the left coronary artery. Ten patients had plain old balloon angioplasty, 10 had percutaneous transluminal rotational atherectomy, and 12 had stent implantation. Blood samples were drawn from the coronary sinus before and immediately after PTCA. Plasma concentrations of interleukin 6 (IL-6), platelet derived growth factor (PDGF), monocyte chemoattractant protein 1 (MCP-1), and macrophage coronary stimulating factor (M-CSF) were measured. The patients were scheduled for follow up angiography six months after PTCA. Late loss index was calculated using quantitative coronary angiography. RESULTS: IL-6 concentrations in coronary sinus blood increased immediately after PTCA (p < 0.001), but there was no change in PDGF, MCP-1, or M-CSF. There was a positive correlation between changes in IL-6 concentrations immediately after PTCA and late loss index six months after PTCA (r = 0.73, p < 0.001). IL-6 concentrations in coronary sinus blood were higher in patients with late restenosis than in those without restenosis (p < 0.001). CONCLUSIONS: PTCA induces IL-6 production in the coronary circulation. This may induce subsequent inflammatory responses in injured vessels and play an important role in late restenosis after PTCA.

Adult↗
PubMed2000

Effects of aspirin-like drugs on nitric oxide synthesis in rat vascular smooth muscle cells.

The purpose of this study was to investigate the effects of aspirin-like drugs on nitric oxide (NO) synthesis in rat vascular smooth muscle cells (VSMCs). We measured the accumulation of nitrite, a stable oxidation product of NO, and the expression of inducible NO synthase (iNOS) mRNA and protein in rat cultured VSMCs. Sodium salicylate, aspirin, and indomethacin dose-dependently enhanced nitrite production by interleukin (IL)-1beta-stimulated VSMCs at therapeutic plasma concentration ranges. Increased nitrite production by aspirin-like drugs was accompanied by increased iNOS mRNA and protein accumulation in VSMCs. Addition of IL-1beta activated nuclear factor kappaB (NF-kappaB) in VSMCs, but sodium salicylate did not affect IL-1beta-induced NF-kappaB activation. The nonselective lipoxygenase (LO) inhibitor nordihydroguaiaretic acid inhibited sodium salicylate-induced nitrite production, whereas the selective 5-LO inhibitor caffeic acid did not influence production of nitrite. The 12-LO product 12-HETE dose-dependently enhanced nitrite production by IL-1beta-stimulated VSMCs, whereas the 15-LO product 15-HETE did not. Our study demonstrates that aspirin and the aspirin-like drugs, sodium salicylate and indomethacin, increase NO synthesis in IL-1beta-stimulated VSMCs by upregulation of iNOS transcription via a 12-LO pathway. These effects were independent of NF-kappaB activation. In addition to the direct inhibition of platelet function, aspirin-like drugs may contribute to the reduction of atherothrombotic risk in myocardial ischemia via enhancing NO production by VSMCs.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗
PubMed2000

Peroxisome proliferator-activated receptor-gamma ligands inhibit nitric oxide synthesis in vascular smooth muscle cells.

Peroxisome proliferator-activated receptor-gamma (PPARgamma) is a key player in glucose metabolism. If PPARgamma ligands modulate nitric oxide (NO) synthesis in the vascular tissue, they may affect the process of plaque formation and postangioplasty restenosis. We investigated the effects of PPARgamma ligands on NO synthesis in vascular smooth muscle cells. Incubation of cultures with interleukin-1beta (10 ng/mL) for 24 hours caused a significant increase in the production of nitrite, a stable metabolite of NO, in cultured rat vascular smooth muscle cells. The PPARgamma agonists troglitazone and 15-deoxy-triangle up(12,14)-prostaglandin J(2) (15d-PG J(2)) dose-dependently inhibited nitrite production by interleukin-1beta-stimulated vascular smooth muscle cells. Decreased interleukin-1beta-induced nitrite production by the PPARgamma agonists was accompanied by decreased inducible NO synthase mRNA and protein accumulation. Interleukin-1beta induced nuclear factor-kappaB activation in vascular smooth muscle cells, and both troglitazone and 15d-PG J(2) markedly suppressed this nuclear factor-kappaB activation. PPARgamma ligands inhibit NO synthesis in cytokine-stimulated vascular smooth muscle cells, suggesting that these agonists may act directly on the vascular smooth muscle and influence the process of atherosclerosis and restenosis.

Animals↗