Biomedical subjects

T Shioi

Publications and source records attributed to T Shioi.

33 records · Page 2Linked to original sources

PubMed1997

Enhanced expression of hepatocyte growth factor/c-Met by myocardial ischemia and reperfusion in a rat model.

BACKGROUND: Hepatocyte growth factor (HGF) is a multifunctional factor implicated in tissue regeneration, wound healing, and angiogenesis. Circulating HGF is reportedly elevated during the early stage of myocardial infarction. However, its precise effect on the heart is unknown. To evaluate the regulation of HGF in ischemically damaged myocardium, the production of HGF and its high-affinity receptor, c-Met, was studied in a rat model of myocardial ischemia and reperfusion. METHODS AND RESULTS: The plasma concentration of HGF began to increase within 1 hour of reperfusion after 1 hour of ischemia. The peak level was reached at 3 hours after reperfusion. Northern blotting revealed that HGF mRNA expression in the heart was augmented threefold at 24 and 48 hours and remained elevated by twofold at 120 hours after the myocardium was reperfused. The signal for c-met, high-affinity HGF receptor mRNA, was also upregulated parallel to upregulation for HGF. In the kidney, liver, lung, and spleen, HGF mRNA was also maximally increased at 12 hours after reperfusion. However, c-met was not upregulated in these organs. Immunohistochemical studies disclosed that capillary endothelial and interstitial cells, including infiltrating macrophages, were intensely stained for HGF, whereas capillary endothelial cells in the reperfused myocardium were positive for c-Met. CONCLUSIONS: This study is the first to show that myocardial ischemia and reperfusion induced HGF expression in various organs in vivo. These results indicate that HGF/c-Met plays a role in capillary endothelial cell regeneration in the ischemically injured heart.

Animals↗

PubMed1997

Beneficial effects of amlodipine in a murine model of congestive heart failure induced by viral myocarditis. A possible mechanism through inhibition of nitric oxide production.

BACKGROUND: Although calcium channel blockers have not been shown to be beneficial for the treatment of patients with heart failure, a recent clinical trial demonstrated a favorable effect of amlodipine on the survival of patients with heart failure resulting from nonischemic dilated cardiomyopathy. We investigated the effects of amlodipine on a murine model of congestive heart failure induced by the M variant of encephalomyocarditis virus (EMCV). METHODS AND RESULTS: Four-week-old male DBA/2 mice were inoculated with EMCV and administered amlodipine, diltiazem, or vehicle PO for 2 weeks. The heart weight-to-body weight ratio and the histopathological grades of myocardial lesions were significantly lower and survival was significantly increased in the amlodipine-treated group (P < .01, P < .05, and P < .05, respectively) than in the control group. In vitro, amlodipine added to murine J774A.1 macrophages concomitant with EMCV inhibited nitrite formation in a concentration-dependent manner, but diltiazem did not. Furthermore, NG-monomethyl-L-arginine, an inhibitor of NO synthesis, decreased myocardial lesions significantly in this murine model. Immunohistochemistry revealed that the number of cells stained with antibody against an inducible NO synthase decreased significantly in the amlodipine-treated group compared with that in the control group (P < .01). CONCLUSIONS: Amlodipine appears to have a protective effect against myocardial injury in this animal model of congestive heart failure. The therapeutic effect of amlodipine may be in part resulting from inhibition of overproduction of NO.

Amlodipine↗

PubMed1997

Plasma levels of the monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 are elevated in patients with acute myocardial infarction.

Cardiac inflammatory responses appear to play a pivotal role in scar formation after acute myocardial infarction. Monocyte chemotactic and activating factor (MCAF) monocyte chemoattractant protein-1 (MCP-1) is a cytokine with chemotactic activity for mononuclear phagocytes, but also for NK cells, T cells, mast cells, and basophils. To investigate the possible involvement of MCAF/MCP-1 in the pathogenesis, its course was studied in patients with acute myocardial infarction. Twenty-three consecutive patients with acute myocardial infarction and 18 patients with angina pectoris were studied. Cytokines were measured by enzyme-linked immunosorbent assay. Plasma levels of interleukin IL-1alpha, IL-1beta, and IL-2 were below the detection limit of our method. IL-6 and interferon-gamma were detected in 17.4%, and tumor necrosis factor-alpha in 13.0% of patients with acute myocardial infarction, but the frequency was not statistically significantly different from that in angina pectoris. The plasma level of MCAF/MCP-1 in myocardial infarction tended to increase at 3 h after the onset of chest pain (133 +/- 19 pg/ml, P= 0.06) and was significantly elevated at 9 h (143 +/- 20 pg/ml) when compared with that in angina pectoris (87 +/- 6 pg/ml, P<0.05). The MCAF/MCP-1 level remained increased during the 24-hours observation period (P<0.01), and maximum level (168 +/- 13 pg/ml) was seen at 24 hour. The level of MCAF/ MCP-1 correlated significantly with the plasma level of another chemokine, IL-8, at 12 h after the onset of chest pain (r=0.51, P<0.05), suggesting that common stimuli mediate the release of both cytokines in myocardial infarction. The identification of MCAF/MCP-1 as an inflammatory mediator in acute myocardial infarction suggests that mononuclear phagocytes may play an important role in the early stage of the disease.

Adult↗

PubMed1997

Protective role of interleukin-12 in viral myocarditis.

The co-ordinate action of several cytokines determines the nature, severity and duration of myocarditis. Interleukin (IL)-12 mediates a broad range of effects on both innate and acquired immunity. However, the in vivo role of IL-12 in viral myocarditis remains to be elucidated. To clarify the role of IL-12 in viral myocarditis, we treated mice inoculated with the encephalomyocarditis virus (EMCV), with recombinant IL-12 and neutralizing anti-IL-12 antibody. The successive administration of 10 ng of IL-12 from the day of virus inoculation to 5 days thereafter, reduced mortality, myocardial damage and viral replication in the heart tissue. The gene expression of IL-12p35 and IL-12p40 was enhanced in the hearts of EMCV inoculated mice. Treatment with neutralizing anti-IL-12 resulted in increased mortality of mice inoculated with EMCV. In conclusion, endogenous and exogenous IL-12 play protective roles in murine viral myocarditis.

Animals↗

PubMed1997

Increased expression of interleukin-1 beta and monocyte chemotactic and activating factor/monocyte chemoattractant protein-1 in the hypertrophied and failing heart with pressure overload.

Studies on the effects of proinflammatory cytokines on the heart suggest that they play some roles in the pathogenesis of congestive heart failure (CHF). To determine the involvement of proinflammatory cytokine in cardiac hypertrophy and CHF induced by mechanical overload, we investigated the expression of interleukin (IL)-1 beta and monocyte chemotactic and activating factor (MCAF)/monocyte chemoattractant protein-1 (MCP-1) in the left ventricle (LV) of Dahl salt-sensitive (DS) rats that showed hypertrophy of the LV induced by hypertension and subsequently developed CHF. The IL-1 beta mRNA content in the LV of DS rats increased 3.9-fold when LV hypertrophy developed, and the increase reached 6.2-fold at the CHF stage compared with that of age-matched Dahl salt-resistant (DR) rats. The amount of IL-1 beta in the LV was positively correlated with the LV weight/body weight ratio. Most of the IL-1 beta immunoreactivity was localized in the endothelial cells and interstitial macrophages. The mRNA levels of MCAF in the LV increased 3.6-fold at 11 weeks and reached 4.8-fold at the CHF stage relative to the age-matched DR rats. MCAF protein was localized to the endothelial cells and interstitial macrophages. In DS rats, the number of interstitial macrophages increased diffusely throughout the LV. We suggest that increased chemokine expression, macrophage infiltration, and proinflammatory cytokine expression play some role in the pathogenesis of cardiac hypertrophy and failure induced by chronic mechanical overload.

Animals↗

PubMed1996

Autoimmune response in chronic ongoing myocarditis demonstrated by heterotopic cardiac transplantation in mice.

BACKGROUND: Autoimmune mechanisms have been implicated in the pathogenesis of chronic ongoing myocarditis. To investigate this relation, we used an A/J mouse model inoculated with coxsackievirus B3 and determined whether myocarditis would be transferred to normal hearts that were heterotopically transplanted. METHODS AND RESULTS: Inbred 3-week-old A/J mice were inoculated intraperitoneally with coxsackievirus B3 (Nancy strain; 2 x 10(4) plaque-forming units) and housed for > 60 days. The presence of the viral genome in the myocardium was determined by the polymerase chain reaction with primers specific for the 5' end of the coxsackievirus B3 genome performed at 40, 50, or 60 days after inoculation. Normal A/J mouse hearts were transplanted into the same strain of mice without myocarditis (group A) and into mice with chronic ongoing myocarditis (group B). The hearts were evaluated histologically 2 weeks after transplantation. Conventional histological examination of infiltrated T cells and macrophages was performed, and the expression of intercellular adhesion molecule-1, major histocompatibility complex (MHC) class I antigen, and MHC class II antigen was evaluated by immunoenzymatic staining. The concentrations of interleukin-1 alpha (IL-1 alpha) and tumor necrosis factor (TNF-alpha) in the grafts were measured with an ELISA. The viral RNA genomes were not detected in the mice with chronic ongoing myocarditis, but their transplanted hearts did show myocarditis. In the hearts with induced myocarditis, infiltrated mononuclear cells consisted of CD4+ T cells, CD8+ T cells (CD4+ cell number > CD8+ cell number), and macrophages. Intercellular adhesion molecule-1, MHC class I antigen, and MHC class II antigen were expressed in the vascular endothelial cells and myocardial cells in and around the infiltrated lesions. The concentrations of IL-1 alpha and TNF-alpha in group B were significantly higher than those in group A (group A versus group B: IL-1 alpha, 125 +/- 35 versus 180 +/- 34 pg/mL; TNF-alpha, 45 +/- 15 versus 96 +/- 40 pg/mL; P < .05). CONCLUSIONS: Results suggest that an autoimmune response may play a key role in the progression of chronic ongoing myocarditis.

Animals↗

PubMed1996

Persistent expression of cytokine in the chronic stage of viral myocarditis in mice.

BACKGROUND: Dilated cardiomyopathy (DCM) is one of the most frequent causes of heart failure of unknown origin. One possible cause of DCM is considered to be a sequel to myocarditis. However, the mechanism of progression from viral myocarditis to DCM is still not clear. METHODS AND RESULTS: The expression of the immunoregulatory cytokines interferon (IFN)-gamma and interleukin (IL)-2 and the proinflammatory cytokines IL-1 beta and tumor necrosis factor (TNF)-alpha in the heart tissue was studied in a murine model of postmyocarditis DCM induced by encephalomyocarditis virus. IFN-gamma, IL-1 beta, and TNF-alpha mRNA increased 3 days after virus inoculation. IL-2 mRNA was detectable 7 days after inoculation. The peak expression of all cytokine genes examined was seen 7 days after inoculation. The expression of these cytokine genes decreased thereafter but persisted 80 days after inoculation. IL-1 beta gene expression in the chronic stage was relatively high compared with other cytokines and was correlated with the ratio of heart weight to body weight and the extent of fibrotic lesions. Immunohistochemical analysis revealed that some of the mononuclear cells, endothelial cells, and interstitial macrophages were positive for IL-1 beta or TNF-alpha and fibroblasts were positive for IL-1 beta in the heart tissue of mice 80 days after inoculation. CONCLUSIONS: Persistent expression of cytokines was seen in a murine model of postmyocarditis DCM. These cytokines may have important implications in the pathogenesis of DCM.

Animals↗

PubMed1996

Detection of hepatitis C virus RNA from the heart of patients with hypertrophic cardiomyopathy.

We investigated hepatitis C virus (HCV) infection in 35 patients with hypertrophic cardiomyopathy and 40 patients with ischemic heart disease who were consecutively admitted to our hospital. Frequency of positive anti-HCV antibody was significantly higher in patients with hypertrophic cardiomyopathy (6 of 35 patients, 17.1%) than that in patients with ischemic heart disease (1 of 40 patients, 2.5%, p = 0.036). In three of these six patients with hypertrophic cardiomyopathy, HCV RNA was detected in myocardial tissue. In two of these three patients, HCV RNA was detected from biopsy and autopsy specimens of the ventricles, but not in the serum, suggesting that HCV may replicate in myocardial tissue and may be relevant to ventricular hypertrophy. Thus, HCV infection may play a role in the development of hypertrophic cardiomyopathy.

Adolescent↗

PubMed1996

Increased circulating hepatocyte growth factor in the early stage of acute myocardial infarction.

We measured serum hepatocyte growth factor (HGF) in patients with acute myocardial infarction, angina pectoris, and other heart diseases. In patients with acute myocardial infarction, blood was collected at the time of admission. Serum HGF was elevated within 3 hours in 8 of 10 patients (80%) with acute myocardial infarction after onset of chest pain (9.4 +/- 3.2 ng/mL, mean +/- SEM, values in normal subjects <0.39 ng/mL). Mean value of serum HGF was 11.0 +/-2.6 ng.mL (n=11) in patients who admitted to the hospital between 6 and 9 hours and 13.1 +/- 5.7 ng.mL between 12 and 24 hours after onset. Elevated HGF levels were significantly more frequent than those of creatine kinase within 3 hours, and elevated levels correlated well with those of serum creatine kinase at 6-9 hours after onset of acute myocardial infarction. No increase in serum HGF value was found in patients with angina pectoris or other heart diseases. Thus, measurement of HGF is a sensitive method for early diagnosis of acute myocardial infarction.

Aged↗

PubMed1996

Differential modulation of cytokine production by drugs: implications for therapy in heart failure.

We studied the effects of various phosphodiesterase (PDE) III inhibitors: amrinone, pimobendan and vesnarinone: a PDE IV inhibitor (Ro 20-1724) and a PDE V inhibitor (E-4021) on the production of cytokines which have been shown to depress myocardial function. Recently developed inotropic agents which inhibit PDE III activity have produced short-term hemodynamic benefits in patients with advanced heart failure, but long-term treatment with these agents has an adverse effect on survival. However, vesnarinone, which has been shown to improve survival dramatically, has an immunomodulating effect and inhibits the production of cytokines. Peripheral blood mononuclear cells obtained from healthy human subjects were stimulated with lipopolysaccharide and each PDE inhibitor was added. After 24 h of incubation, tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta) and IL-6 in the culture supernatants were measured by an enzyme-linked immunosorbent assay. All three PDE III inhibitors, amrinone, pimobendan and vesnarinone, inhibited TNF-alpha production, but vesnarinone's inhibitory effect was the most prominent. Amrinone and pimobendan enhanced IL-1 beta production, whereas vesnarinone had no effect. Vesnarinone inhibited IL-6 production and pimobendan slightly decreased IL-6 production, whereas amrinone had no significant effect on IL-6 production. The PDE IV inhibitor, Ro 20-1724, decreased the production of IL-1 beta and TNF-alpha and also tended to inhibit IL-6 production; its modulation of cytokine production was similar to the effects of vesnarinone. Because 8Br-cAMP or 8Br-cGMP did not suppress cytokine production, the modulating effects were not considered to result from an increase in cAMP or cGMP. Differential modulation of cytokine production may play a role in the therapeutic effect in heart failure patients who are treated with drugs that have PDE-inhibitory actions. It may be important to study whether the use of dual inhibitors of PDE III and PDE IV is therapeutically more useful for the treatment of heart failure due to their immunomodulating properties.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1996

Inotropic agents differentially inhibit the induction of nitric oxide synthase by endotoxin in cultured macrophages.

We investigated the effects of inotropic agents with phosphodiesterase III inhibitory properties, amrinone, pimobendan and vesnarinone, and cell permeable cyclic nucleotide analogue, 8-bromo adenosine 3'5'-cyclic monophosphate (8 Br-cAMP) on the induction of nitric oxide synthase (NOS) by lipopolysaccharide in J774A.1 macrophages in vitro. Although all three inotropic agents inhibited nitrite accumulation, the degree of inhibition was different, with pimobendan being the most potent inhibitor and amrinone the least. Vesnarinone inhibited nitrite formation biphasically. 8 Br-cAMP increased nitrite production at high concentrations, suggesting that the inhibitory effects of inotropic agents could not be explained by an increase in cAMP. Although differential inhibition of inducible NOS by inotropic agents may explain the different effects of these drugs in patients with heart failure, further study is necessary to reach this conclusion.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1996

Immunomodulation: a new horizon for medical treatment of heart failure.

Recently, the intriguing possibility has been raised that heart failure may be mediated by the biological effects of cytokines. Indeed, we found elevation of plasma concentrations of various cytokines in patients with myocardial disease. We also detected positive tumor necrosis factor (TNF-alpha) immunoreactivity in right atrial tissues obtained during surgery from patients with severe heart failure. Therefore, we postulated that some aspects of heart failure may be related to non-lethal down-modulation of cardiac function by immune cells and their cytokines. Testing this hypothesis in an experimental model of murine myocarditis, we found that injection of recombinant human TNF-alpha increased mortality of the animals infected with myocarditis virus. The anti-TNF-alpha monoclonal antibody improved survival and attenuated the myocardial lesions. Whereas, administration of recombinant human IL-2 in the acute viremic stage increased survival rate, and resulted in less intense pathological changes in the myocardium while in the subacute aviremic stage, the same amount of IL-2 reduced survival rate and exacerbated severity of the disease. Therefore, cytokine release may initiate a beneficial inflammatory and immune response in the acute phase of the disease process, but the continued induction of cytokines and the enhanced natural killer (NK) cell activity in the later stage are no longer protective. Vesnarinone, a recently synthesized inotropic agent which has proved to benefit patients with congestive heart failure by improving prognosis, also increased the survival of individual subjects in the above-mentioned murine model of heart failure. Cytotoxicity of NK cells obtained from the virus infected animals was substantially reduced when treated with vesnarinone. Vesnarinone also inhibited production of TNF-alpha and other cytokines from stimulated human lymphocytes and cultured murine splenocytes. We conclude, therefore, that inhibition of NK cell activity and suppression of cytokine production appear to be important immunological defense mechanisms which could contribute to the observed salutary effects of vesnarinone in the treatment of chronic heart failure. More broadly, immunomodulation could pave the way for a new frontier in the management of heart failure.

Adjuvants, Immunologic↗

PubMed1994

Inhibition of cytokine production by a new inotropic agent, vesnarinone, in human lymphocytes, T cell line, and monocytic cell line.

Vesnarinone, a recently synthesized quinolinone derivative with positive inotropic properties, has been reported to improve survival of patients with congestive heart failure. However, the mechanisms that contribute to the increased survival are unknown. In this study, we showed vesnarinone had inhibitory effects on the production of tumor necrosis factor-alpha, interferon-gamma, interleukin-1 beta and interleukin-2 by stimulated human peripheral blood mononuclear cells, human Jurkat T cell line and THP-1 monocytic cell line. Vesnarinone may exert its beneficial effect on patients with congestive heart failure, in part, by its immunomodulating activity.

Adult↗

PubMed1994

Vesnarinone, a new inotropic agent, inhibits cytokine production by stimulated human blood from patients with heart failure.

BACKGROUND: Vesnarinone, a quinolinone derivative, is a recently synthesized positive inotropic agent that has been shown to dramatically improve the survival of patients with heart failure. However, the mechanism of action of vesnarinone remains unknown. Reversible neutropenia complicated with vesnarinone therapy suggests that vesnarinone may modulate the production of cytokines. Because tumor necrosis factor (TNF)-alpha and other cytokines have been shown to depress myocardial contractility, we investigated the effects of vesnarinone on the production of various cytokines. METHODS AND RESULTS: We studied the effects of vesnarinone on cytokine production by lipopolysaccharide (LPS)-stimulated whole blood from seven patients with heart failure and from five healthy volunteers. Heparinized blood was diluted in RPMI and stimulated with LPS. Vesnarinone was added in a range of 1 to 30 micrograms/mL, the blood was incubated for 24 hours, and interleukin (IL)-1 alpha, IL-1 beta, IL-6, TNF-alpha, interferon (IFN)-gamma, and granulocyte colony-stimulating factor (G-CSF) were measured by an enzyme-linked immunosorbent assay. LPS stimulation induced a more prominent increase in TNF-alpha in patients with heart failure than in healthy volunteers. Vesnarinone inhibited the production of TNF-alpha and IFN-gamma both in healthy volunteers and in patients with heart failure. IL-1 alpha and IL-1 beta were also suppressed in healthy volunteers, but this response was variable, and a significant reduction was not seen in patients with heart failure. Marked inhibition of G-CSF and other cytokines by vesnarinone was observed in one patient who had developed neutropenia as a result of vesnarinone therapy. CONCLUSIONS: Although the number of study patients was small and the results are preliminary, these findings provide evidence that vesnarinone plays an important role in the regulation of cytokines and suggest that the reduction of cytokine release may contribute to the beneficial effects of the drug in the treatment of heart failure. Furthermore, the measurement of cytokines may be useful in predicting the occurrence of neutropenia, which has been occasionally reported in patients treated with vesnarinone.

Blood↗

PubMed1983

Decalcification for electron microscopy with L-ascorbic acid.

L-Ascorbic acid decalcification was used for electron microscopy of mammalian tooth germs and bone after fixation in a glutaraldehyde-paraformaldehyde mixture. The recommended decalcifying solution is 2% with respect to L-ascorbic acid and 0.9% with respect to sodium chloride. The method has the advantage that decalcification is complete within a quarter of the time required with EDTA. The fine structure of ameloblasts and hard tissue is preserved as well as with EDTA.

Ameloblasts↗