Quantitative Evaluation of Intraarterial Lymphocyte Injection Therapy for Lymph Edema Using MR Imaging

Five patients with unilateral leg lymph edema had intraarterial injections of lymphocytes in the affected leg with consequent improvement in 3. To assess the degree of lymph edema, T2 and intensity ratio between the 2 legs in STIR images were used. Mean and SD of T2 values in the subcutaneous tissue were measured using a triple echo sequence and found larger on the edematous side than in the opposite extremity. The mean T2 shortening obtained after the lymphocyte therapy correlated well with the reduction of limb circumference. Mean T2 reflects the fluid content, and SD of T2 the fluid distribution in the subcutaneous tissue. The degree of lymph edema and the effect of therapy can be evaluated quantitatively by measuring the value of the T2 relaxation time.

Relation between C reactive protein concentrations and coronary microvascular endothelial function

OBJECTIVE

To determine how C reactive protein (CRP), a sensitive marker of inflammation, is related to coronary endothelial function.

DESIGN

Changes in quantitative coronary angiographic findings and Doppler flow velocity measurements in response to locally infused acetylcholine were assessed.

SETTING

Tertiary cardiology centre.

PATIENTS

46 patients with angiographically normal coronary arteries were divided into groups with normal (< or = 3 mg/l) or increased (> 3 mg/l) CRP concentrations.

INTERVENTIONS

Acetylcholine (3 and 30 microg/min) was infused into the left coronary ostium for two minutes.

MAIN OUTCOME MEASURES

Percentage change in diameter of epicardial coronary arteries and coronary blood flow (CBF) in response to acetylcholine; and correlations between these parameters and serum CRP concentrations.

RESULTS

15 patients had increased CRP concentrations. The change in coronary artery diameter induced by acetylcholine infusion was similar between the groups but the increase in CBF induced by acetylcholine was smaller in patients with increased CRP concentrations (54.9% v 139.4% with acetylcholine 30 microg/min, p = 0.0030). Multivariate analysis identified increased CRP concentration as independently associated with attenuated CBF response to acetylcholine at 30 microg/min (p = 0.0078, R2 = 0.434).

CONCLUSIONS

These findings suggest that inflammation appears to be associated with impaired coronary endothelial function in resistance but not conduit vessels. The data suggest a close relation between chronic vascular inflammation and endothelial dysfunction in atherosclerosis.

[Infant case and adult case of scimitar syndrome with lung sequestration]

We present 2 cases of Scimitar syndrome with lung sequestration, 1 of which is infant case and the other is adult. A 3-month-old baby was transferred to our hospital because of severe heart failure. Cardiac ultrasonography and angiography revealed atrial septal defect and lung sequestration. Because of critical condition, she underwent emergency operation. After the operation of abnormal lung resection, her general condition improved. We emphasize that the prognosis is influenced by operation timing. A 20-year-old female was admitted for atrial septal defect. We diagnosed Scimitar syndrome and lung sequestration as the result of close examinations. We carried out definitive operations of the closure of atrial septal defect, the correction of partially anomalous pulmonary venous return and the resection of malformed lung. This adult case is popular one of Scimitar syndrome.

Endothelin-1 is a potent stimulator of alpha1beta1 integrin-mediated collagen matrix remodeling by rat mesangial cells

Endothelin-1 (ET) is known to stimulate mesangial cell (MC) proliferation, extracellular matrix (ECM) synthesis, and thereby contribute to the progression of glomerulonephritis (GN). To clarify the molecular and cellular mechanisms of how ET is involved in the development of glomerular sclerosis, we investigated the influence of ET on the MC-alpha1beta1 integrin-mediated collagen matrix reorganization using a collagen gel contraction assay. ET enhanced MC-alpha1beta1 integrin-mediated gel contraction in a dose-dependent manner. Addition of the endothelin A (ETA) receptor antagonist, BQ123, into collagen gels abolished ET-induced gel contraction by MC. Cell behavior involved in ET-induced gel contraction was investigated in combination with function-blocking anti-alpha1-integrin antibody. Migration and adhesion assays revealed that ET stimulated alpha1beta1 integrin-mediated MC migration but did not influence cell adhesion to type I collagen (collagen I). Integrin-function blocking studies using anti-alpha1 integrin antibody indicated that MC-alpha1beta1 integrin is required not only for collagen-dependent migration, but also for gel contraction. Zymography showed that ET increased MC matrix metalloproteinase-2 (MMP-2) activity in a dose-dependent manner during MC-induced gel contraction process. Finally, flow cytometry analysis indicated that ET did not affect the cell surface expression of the MC-alpha1beta1 integrin within the collagen gel. These data suggested that ET promotes collagen matrix reorganization through the enhancement of MC-alpha1beta1 integrin-dependent migration and MMP-2 activity. We therefore conclude that ET is a potential molecule inducing pathological collagen matrix remodeling observed in progressive GN.

Estrogen receptor beta is involved in the anorectic action of estrogen

OBJECTIVE

Estrogen has been implicated in feeding behavior and adiposity. This study was undertaken to elucidate the mechanism underlying the anti-obesity and anorectic action of estrogen and the role of estrogen receptor (ER) in the central nervous system.

METHODS AND RESULTS

Ovariectomy in 8-week-old female Wistar rats induced hyperphagia along with an increase in body weight and abdominal fat accumulation compared to control sham-operated rats. These changes were fully reversed by subcutaneous replacement of estradiol and were abrogated by pair-feeding. Then, the effects of intracerebroventricular infusion of estradiol, alone or in combination with antisense oligodeoxynucleotides (ODN), for ER in ovariectomized rats were examined. The estradiol group showed 10-20% lower daily food intake, and after the 2-week infusion period a 14% reduction in body weight with a similar reduction in abdominal fat compared to the vehicle group. The inhibitory effect of estradiol on food intake and body weight was blocked by co-administration of ER-beta antisense ODN, whereas ER-alpha antisense ODN did not show any influence.

CONCLUSION

These results indicate that ER-beta in the central nervous system is involved in the anorectic action of estrogen.

Bcr in vascular smooth muscle cells involvement of Ras and Raf-1 activation by Bcr

Bcr gene was originally identified by its presence in the chimeric Bcr/Abl oncogene. In vascular smooth muscle cells, platelet-derived growth factor-BB (PDGF) stimulated Bcr kinase activity. The mutant PDGF receptor for PI3-K, but not for PLC-gamma binding sites, showed significantly reduced Bcr kinase activity. Bcr wild-type enhanced, whereas Bcr kinase negative form inhibited PDGF-stimulated ERK1/2 activity. A dominant negative Ras did not inhibit Bcr kinase activation, and overexpression of Bcr increased Ras/Raf-1 activity and DNA synthesis. These results demonstrated the importance of Bcr in PDGF-mediated events such as activation of Ras, Raf-1, and ERK1/2 and stimulation of DNA synthesis.

Effects of losartan in combination with or without exercise on insulin resistance in Otsuka Long-Evans Tokushima Fatty rats

Hypertension often complicates type 2 diabetes mellitus, and angiotensin converting enzyme inhibitor treatment has been shown to improve insulin resistance in such cases. However, the effect of angiotensin II type-1 (AT(1)) receptor antagonists on insulin resistance is still controversial. To gain further information on this effect, we examined the effect of losartan on insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model of type 2 diabetes mellitus. Losartan administration alone lowered systolic blood pressure, but did not improve oral glucose tolerance test or insulin resistance in OLETF rats. However, the administration of losartan with exercise significantly improved both systolic blood pressure and insulin resistance relative to control OLETF rats. On the other hand, losartan treatment, regardless of exercise, increased glucose uptake in excised soleus muscle and fat cells. To explore the beneficial effect of losartan on skeletal muscle glucose uptake, we examined intracellular signaling of soleus muscle. Although Akt activity and glucose transporter type 4 (GLUT4) expressions were not affected by losartan with or without exercise, extracellular signal-regulated kinase (ERK1/2) and p38 mitogen-activated protein (MAP) kinase activities were increased by both interventions. These results indicate that angiotensin AT(1) receptor antagonist improved local insulin resistance, but not systemic insulin resistance. These findings may explain the controversy over the effect of angiotensin AT(1) receptor antagonists on insulin resistance in clinical use. The enhancing effect of angiotensin AT(1) receptor antagonist on skeletal muscle glucose uptake may be attributable to MAP kinase activation or other mechanisms rather than phosphatidylinositol 3-kinase activation.

Acute and chronic smooth muscle cell apoptosis after mechanical vascular injury can occur independently of the Fas-death pathway

Vascular smooth muscle cell (VSMC) apoptosis has been demonstrated in vascular lesions, such as atherosclerotic and postangioplasty restenotic lesions. Balloon injury also induces VSMC apoptosis. Fas is a death factor that mediates apoptosis when it is activated by its ligand, FasL. Fas-mediated apoptosis was found to be implicated in the pathogenesis of vascular diseases in which Fas/FasL expression was detected. We investigated whether the Fas/FasL interaction mediated acute and chronic VSMC apoptosis and lesion formation in a vascular injury model that may resemble balloon angioplasty. A large spring wire was inserted into the femoral artery of C3H/HeJ (wild-type), C3H-gld (Fas ligand-/-), and C3H-lpr (Fas-/-) mice. The wire was left in place for 1 minute to denude and expand the artery. Massive apoptosis was observed in medial VSMCs from 1 to 7 hours later. There was no difference in the number of apoptotic cells among the 3 groups of mice 4 hours after injury. At 4 weeks, the injured arteries presented signs of concentric neointimal hyperplasia composed exclusively of VSMCs. There was no difference in the degree of neointima hyperplasia (intima/media ratios were as follows: wild type 1.4+/-0.3, gld 1.0+/-0.2, and lpr 1.3+/-0.2) or in the number of apoptotic nuclei among the 3 groups. These findings suggest the existence of other signaling pathways for acute and chronic VSMC apoptosis, at least that induced by mechanical vascular injury.

Src family kinase and adenosine differentially regulate multiple MAP kinases in ischemic myocardium: modulation of MAP kinases activation by ischemic preconditioning

Recent studies suggest that ischemia activates Src and members of the mitogen-activated protein (MAP) kinase superfamily and their downstream effectors, including big MAP kinase 1 (BMK1) and p90 ribosomal S6 kinase (p90RSK). It has also been reported that adenosine is released during ischemia and involved in triggering the protective mechanism of ischemic preconditioning. To assess the roles of Src and adenosine in ischemia-induced MAP kinases activation, we utilized the Src inhibitor PP2 (4-Amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo[3,4-d]pyrimidine) and the adenosine receptor antagonist 8-(p-sulfophenyl) theophylline (SPT) in perfused guinea pig hearts. PP2 (1 microm) inhibited ischemia-induced Src, BMK1 and JNK activation but not JAK2 and p38 activation. SPT inhibited ischemia-mediated p38 and JNK activation. These results demonstrate that Src family kinase and adenosine regulate MAP kinases by parallel pathways. Preconditioning significantly improved both recovery of developed pressure and dp/dt in isolated guinea pig hearts. Since the protective effect of preconditioning was blocked by PP2 (1 microm) and SPT (50 microm), we next investigated the regulation of Src, MAP kinases and p90RSK during preconditioning. The activity and time course of ERK1/2 was not changed, but p90RSK activation by reperfusion was completely inhibited by preconditioning. In contrast, the activation by ischemia of Src, BMK1, p38 and JNK was significantly faster in preconditioned hearts. Maximal BMK1 activation by ischemia was also significantly enhanced by preconditioning. These data suggest important roles for Src family kinases and adenosine in mediating preconditioning, and suggest specific roles for individual MAP kinases in preconditioning.

Endothelial nitric oxide synthase is essential for the HMG-CoA reductase inhibitor cerivastatin to promote collateral growth in response to ischemia

HMG-CoA (3-hydroxy-3-methylglutaryl-coenzyme A) reductase inhibitors, or statins, are prescribed widely to lower cholesterol. Accumulating evidence indicates that statins have various effects on vascular cells, which are independent of their lipid-lowering effect. Here, we tested the hypothesis that statins may augment collateral flow to ischemic tissues. We induced hind-limb ischemia in wild-type mice and treated them with either saline or cerivastatin. Cerivastatin enhanced the blood flow recovery dramatically as determined by Laser Doppler imaging. The mice treated with saline displayed frequent autoamputation of the ischemic toe, which was prevented completely by cerivastatin. Anti-CD31 immunostaining revealed that cerivastatin significantly increased the capillary density. Endothelial nitric oxide synthase (eNOS) activity was enhanced markedly in the mice treated with cerivastatin. The angiogenic effect of cerivastatin was abrogated in eNOS deficient (eNOS-/-) mice. These results indicate that eNOS is essential for cerivastatin to promote collateral growth in response to ischemia.

Foam cell formation containing lipid droplets enriched with free cholesterol by hyperlipidemic serum

A monoclonal antibody, ASH1a/256C (256C), which binds to atherosclerotic lesions in Watanabe heritable hyperlipidemic rabbit (WHHL) aorta in vivo, recognizes complex structures of phosphatidylcholine mixed with neutral lipids. In the present study, a cell culture system is described in which foam cells express 256C-positive lipid droplets. J774.1 macrophages were incubated in the presence of a small volume of WHHL serum for 24 h to produce foam cells, which were then incubated without the WHHL serum for 3 days. Oil red O-positive lipid droplets appeared on day 1, and were present in the cells during the whole incubation period. The lipid droplets in the cells were positively immunostained with antibody 256C on day 4, although they were negative on day 1. Expression of the antigenic lipid droplets was also induced by the addition of acetylated LDL or sera from patients with hyperlipidemia. When foam cells were induced by the addition of WHHL serum, cellular content of cholesteryl ester was greatly increased but then decreased to near basal levels by day 4. Concomitantly, cellular free cholesterol increased during the culture period, indicating that the cholesteryl ester changes to free cholesterol by day 4. The lipid droplets in the foam cells on day 4 were positively stained with filipin, a fluorescent probe for free cholesterol, as well as with 256C antibody, indicating that free cholesterol is enriched in antigenic lipid droplets. These observations suggest that hydrolysis and rearrangement of cellular cholesterol take place in foam cells to form complex structures of phosphatidylcholine and free cholesterol in lipid droplets.

Induction of nuclear orphan receptor NGFI-B gene and apoptosis in rat vascular smooth muscle cells treated with pyrrolidinedithiocarbamate

NGFI-B is one of the orphan nuclear receptors, and its gene is implicated in the apoptosis of T cells. The aim of this study was to investigate the expression and the role of NGFI-B in vascular smooth muscle cells (VSMCs). Pyrrolidinedithiocarbamate (PDTC) is a modulator of an oxidative state and is reported to induce apoptosis only when the density of VSMCs is low. Under low VSMC density (10 000 cells/cm(2)), addition of PDTC (0.1 to 10 micromol/L) caused apoptosis of VSMCs, which was confirmed by Hoechst 33258 staining under fluorescence microscopy. At low VSMC density, expression of NGFI-B mRNA was induced 1 hour after the addition of PDTC, peaking at 6 hours, and persisted for up to 12 hours. The protein level of NGFI-B was increased 4 hours after PDTC addition and persisted for up to 12 hours. Under low VSMC density, PDTC-induced expression of NGFI-B mRNA was correlated with the magnitude of apoptosis, which was quantified by enzyme immunoassay for histone-associated DNA fragments. In contrast, when the density of VSMCs was high (50 000 cells/cm(2)), PDTC did not induce apoptosis, and the expression of NGFI-B was only transient. This transient expression pattern was also seen when VSMCs were treated with phorbol ester, calcium ionophore, hydrogen peroxide, or angiotensin II, even at low cell density. We next investigated whether the NGFI-B gene may act as a transcription factor under treatment with PDTC by measuring the promoter activity of luciferase reporter plasmids that contained typical NGFI-B-responsive elements. The PDTC-induced transcriptional activity of NGFI-B was 2-fold higher at low cell density than at high cell density. These data demonstrate that NGFI-B can be induced in VSMCs and suggest that NGFI-B may play a role in PDTC-induced VSMC apoptosis.

Quercetin inhibits Shc- and phosphatidylinositol 3-kinase-mediated c-Jun N-terminal kinase activation by angiotensin II in cultured rat aortic smooth muscle cells

Angiotensin II (Ang II) induces vascular smooth muscle cell (VSMC) hypertrophy, which results in various cardiovascular diseases. Ang II-induced cellular events have been implicated, in part, in the activation of mitogen-activated protein (MAP) kinases. Although it has been proposed that daily intake of bioflavonoids belonging to polyphenols reduces the incidence of ischemic heart diseases (known as "French paradox"), the precise mechanisms of efficacy have not been elucidated. Thus, we hypothesized that bioflavonoids may affect Ang II-induced MAP kinase activation in cultured rat aortic smooth muscle cells (RASMC). Our findings showed that Ang II stimulated rapid and significant activation of extracellular signal-regulated kinase (ERK) 1/2, c-Jun N-terminal kinase (JNK), and p38 in RASMC. Ang II-induced JNK activation was inhibited by 3,3',4',5,7-pentahydroxyflavone (quercetin), a major bioflavonoid in foods of plant origin, whereas ERK1/2 and p38 activation by Ang II were not affected by quercetin. Ang II caused a rapid tyrosine phosphorylation of Src homology and collagen (Shc), which was inhibited by quercetin. Quercetin also inhibited Ang II-induced Shc.p85 association and subsequent activation of phosphatidylinositol 3-kinase (PI3-K)/Akt pathway in RASMC. Furthermore, LY294002, a PI3-K inhibitor and a quercetin derivative, inhibited Ang II-induced JNK activation as well as Akt phosphorylation. Finally, Ang II-induced [(3)H]leucine incorporation was abolished by both quercetin and LY294002. These findings suggest that the preventing effect of quercetin on Ang II-induced VSMC hypertrophy are attributable, in part, to its inhibitory effect on Shc- and PI3-K-dependent JNK activation in VSMC. Thus, inhibition of JNK by quercetin may imply its usefulness for the treatment of cardiovascular diseases relevant to VSMC growth.

Collagen synthesis and collagenase activity of cryopreserved heart valves

OBJECTIVE

Durability of the valve seems to be dependent on the remodeling ability of the valve itself, which is controlled by both collagen synthesis and collagenolytic activity of valvular fibroblasts and endothelial cells. However, the balance of collagen synthesis and collagenolysis of the cryopreserved valve has not yet been clearly revealed. Thus, we assessed the collagen synthesis and collagenolysis ability of the cryopreserved valve.

METHODS

Twelve valves were divided into 2 groups: freshly harvested valves (n = 6) and cryopreserved valves (n = 6). We measured the collagen content using Sirius red, a dye selective to the collagen. Collagen synthesis was evaluated by means of the tritiated proline incorporation method. Noncollagenase-digestible counts, which represent protein synthesis, and collagenase-digestible counts, which represent collagen synthesis, were estimated. Collagenase activity of the valves was assessed by gelatin zymography.

RESULTS

The collagen content of the cryopreserved group was maintained. The noncollagenase-digestible counts of the cryopreserved group decreased from 3862 +/- 1180 counts/mg to 1174 +/- 1362 counts/mg, and the collagenase-digestible counts of the cryopreserved group were 831 +/- 762 counts/mg compared with the value of 1062 +/- 136 counts/mg for the freshly harvested group. The collagenase activity of the cryopreserved group was observed at the same level as that of the freshly harvested group, despite the serious endothelial damage of the cryopreserved valves.

CONCLUSIONS

Although the collagen synthesis of cryopreserved valves was relatively maintained, the protein synthesis was highly diminished, and the collagenolysis ability was activated immediately after the thawing process. These results imply that the cryopreservation procedure itself may cause the collagen metabolism to be on the degradable side, which will lead to valve failure.

p160 Bcr mediates platelet-derived growth factor activation of extracellular signal-regulated kinase in vascular smooth muscle cells

BACKGROUND

The human Bcr gene was originally identified by its presence in the chimeric Bcr/Abl oncogene, which is causative for chronic myeloblastic leukemia. Because Bcr encodes a serine/threonine protein kinase, we studied its kinase activity and determined the role of Bcr in the PDGF signaling pathway to ERK1/2 activation and DNA synthesis in rat aortic smooth muscle cells (RASMCs).

METHODS AND RESULTS

In RASMCs, platelet-derived growth factor-BB (PDGF) stimulated Bcr kinase activity, with a maximum at 1 minute. Because phosphatidylinositol 3'-kinase (PI3-K) is essential for Bcr/Abl leukemogenesis, we evaluated the role of mouse PDGF-beta-receptor binding sites for PI3-K (Y708, Y719) and for phospholipase C-gamma (Y977, Y989) in PDGF-mediated Bcr kinase activation. The mutant PDGF receptor Y708F/Y719F but not Y977F/Y989F showed significantly reduced Bcr kinase activity. To determine the role of Bcr in PDGF-mediated signal transduction events leading to ERK1/2 and its downstream Elk1 transcription activation, wild-type (WT) and kinase-negative (KN) Bcr were transiently expressed in RASMCs. Bcr WT enhanced, whereas Bcr KN inhibited, PDGF-stimulated ERK1/2 and Elk1 transcriptional activity. Overexpression of Bcr also enhanced PDGF-induced Ras/Raf-1 activity and DNA synthesis, but this regulation is independent of the kinase activity of Bcr. Finally, we found that Bcr expression was increased in the neointimal layer after balloon injury of rat carotid artery.

CONCLUSIONS

These results demonstrated the importance of Bcr in PDGF-mediated events, such as activation of Ras, Raf-1, ERK1/2, and Elk1, and stimulation of DNA synthesis.

Requirement for tyrosine kinase-ERK1/2 signaling in alpha 1 beta 1 integrin-mediated collagen matrix remodeling by rat mesangial cells

Abnormal mesangial extracellular matrix remodeling by mesangial cells (MCs) is the hallmark of progressive glomerulonephritis (GN). We recently showed, using a type I collagen gel contraction assay, that alpha 1 beta 1 integrin-dependent MC adhesion and migration are necessary cell behaviors for collagen matrix remodeling. To further determine the mechanism of alpha 1 beta 1 integrin-mediated collagen remodeling, we studied the signaling pathways of MCs that participate in the regulation of collagen gel contraction. Immunoprecipitation and phosphotyrosine detection revealed that gel contraction is associated with the enhanced activity and phosphorylation of ERK1/2 by MCs. The tyrosine kinase inhibitors herbimycin and genistein inhibited collagen gel contraction dose dependently. Furthermore, targeting ERK1/2 activity with a MEK inhibitor, PD98059, and antisense ERK1/2 hindered gel contraction in a dose-dependent manner. Similar inhibitory effects on gel contraction and ERK1/2 phosphorylation were observed when MC-mediated gel contraction was performed in the presence of function-blocking anti-alpha1 or anti-beta1 integrin antibodies. However, cell adhesion and migration assays indicated that PD98059 and antisense ERK1/2 blocked alpha 1 beta 1 integrin-dependent MC migration, but did not interfere with collagen adhesion, although there was a marked decrease in ERK1/2 phosphorylation and ERK1/2 protein expression in cell adhesion on type I collagen. None of the above could affect membrane expression of alpha 1 beta 1 integrin. These results suggested that ERK1/2 activation is critical for the alpha 1 beta 1 integrin-dependent MC migration necessary for collagen matrix reorganization. We therefore conclude that ERK1/2 may serve as a possible target for pharmacological inhibition of pathological collagen matrix formation in GN.

Adrenomedullin inhibits angiotensin II-induced expression of tissue factor and plasminogen activator inhibitor-1 in cultured rat aortic endothelial cells

Adrenomedullin (AM) is a potent vasodilating peptide having a variety of pharmacological properties mainly in respect to vascular pathophysiology. We have previously demonstrated that angiotensin II (Ang II) or natriuretic peptides have influence on the expression of tissue factor (TF) and plasminogen activator inhibitor-1 (PAI-1) in vascular endothelial cells. The aim of this study was to elucidate the effects of AM on TF and PAI-1 mRNA and protein expression in endothelial cells. As a result, AM inhibited Ang II-induced TF and PAI-1 mRNA expression in a dose- and time-dependent manner. Because the expression of TF and PAI-1 mRNA induced by Ang II was attenuated by the increase of intracellular concentrations of cAMP by forskolin and 8-bromo-cAMP and because AM increased the intracellular level of cAMP in rat aortic endothelial cells, it was indicated that the inhibitory effect of AM on the expressions of TF and PAI-1 was mainly mediated by the cAMP-dependent signal transduction. Furthermore, the inhibitory effect of AM on TF and PAI-1 expression was partly attenuated by an NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester. In conclusion, AM is shown to contribute to the regulation of blood coagulation and fibrinolysis by vascular endothelial cells mainly via the cAMP pathway.

Fluid shear stress inhibits TNF-alpha activation of JNK but not ERK1/2 or p38 in human umbilical vein endothelial cells: Inhibitory crosstalk among MAPK family members

Atherosclerosis preferentially occurs in areas of turbulent flow and low fluid shear stress, whereas laminar flow and high shear stress are atheroprotective. Inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) and IL-1 stimulate expression of endothelial cell (EC) genes that may promote atherosclerosis. TNF-alpha and IL-1 regulate gene expression in ECs, in part, by stimulating mitogen-activated protein kinases (MAPK), which phosphorylate transcription factors. We hypothesized that steady laminar flow inhibits cytokine-mediated activation of MAPK in EC. To test this hypothesis, we determined the effects of flow (shear stress = 12 dynes/cm(2)) on TNF-alpha and IL-1-stimulated activity of three MAPK in human umbilical vein ECs (HUVEC): extracellular signal-regulated kinase (ERK1/2), p38, and c-Jun N-terminal kinase (JNK). Flow alone stimulated ERK1/2 and p38 activity but decreased JNK activity compared with static controls. TNF-alpha or IL-1 alone activated ERK1/2, p38, and JNK maximally at 15 min in HUVEC. Preexposing HUVEC for 10 min to flow inhibited TNF-alpha and IL-1 activation of JNK by 46% and 49%, respectively, but had no significant effect on ERK1/2 or p38 activation. Incubation of HUVEC with PD98059, which inhibits flow-mediated ERK1/2 activation, prevented flow from inhibiting cytokine activation of JNK. Phorbol 12-myristate 13-acetate, which strongly activates ERK1/2, also inhibited TNF-alpha activation of JNK. These findings indicate that fluid shear stress inhibits TNF-alpha-mediated signaling events in HUVEC via the activation of the ERK1/2 signaling pathway. Inhibition of TNF-alpha signal transduction represents a mechanism by which steady laminar flow may exert atheroprotective effects on the endothelium.

Electron paramagnetic resonance study on free radical scavenging and/or generating activity of dopamine-4-O-sulfate

The free radical scavenging and/or generating activity of dopamine-4-O-sulfate was examined and compared with that of dopamine. In humans, dopamine mostly exists in two isomeric forms of sulfate ester conjugates as metabolites; i.e., dopamine-3-O-sulfate and dopamine-4-O-sulfate in the circulation. Dopamine is generally believed to be oxidized by molecular oxygen or another reactive oxygen species under physiological conditions, to form oxidized dopamine derivatives that are cytotoxic. However, it is not known whether dopamine conjugates are generated on interaction with reactive oxygen species or not. In the present study, we measured the susceptibility to oxidization of dopamine-4-O-sulfate by using electron paramagnetic resonance (EPR) spectroscopy and optical absorption spectrometry. Dopamine was easily oxidized and dopamine-derived radicals appeared, whereas dopamine-4-O-sulfate was not oxidized under physiological conditions. Furthermore, dopamine-4-O-sulfate did not react with a strong oxidizing agent, sodium periodate. These results suggest that dopamine-4-O-sulfate has resistance against autoxidation, and seems to be a stable metabolite of dopamine.

Antioxidants inhibit JNK and p38 MAPK activation but not ERK 1/2 activation by angiotensin II in rat aortic smooth muscle cells

Angiotensin II (Ang II) induces vascular smooth muscle cell (VSMC) hypertrophy, which results in several cardiovascular diseases. Ang II-induced cellular events have been mediated, in part, by reactive oxygen species (ROS) which also involve activation of mitogen-activated protein (MAP) kinases. Although it has been proposed that the therapeutic administration of antioxidants is useful for vascular diseases, the precise mechanisms which regulate ROS-sensitive signaling events have not been well characterized. Thus, we hypothesized that antioxidants may affect ROS-mediated MAP kinases activation induced by Ang II. The present findings showed that Ang II stimulated rapid and significant activation of ERK 1/2, JNK and p38 MAPK in cultured rat aortic smooth muscle cells (RASMC). Ang II-induced ERK 1/2 activation was not affected by all antioxidants examined, whereas JNK was sensitive to all antioxidants. In contrast, p38 MAPK activation was inhibited by DPI and ascorbic acid concentration-dependently, but by NAC only at high concentration. DETC and Trolox C had no effects on p38 MAPK activation by Ang II. We further examined the effects of antioxidants on Ang II-induced increases in oxygen consumption as an index of ROS generation in RASMC. DPI strongly inhibited Ang II-induced increases in oxygen consumption. DETC also inhibited Ang II-induced oxygen consumption, whereas ascorbic acid markedly augmented it. These findings suggest that the inhibitory effects of antioxidants on MAP kinases activation in VSMC are attributable, in part, to their modulating effects on ROS generation by Ang II in VSMC. Thus, inhibition of MAP kinases by antioxidants may imply their usefulness for relief of cardiovascular diseases.

Reversible left ventricular systolic dysfunction--reversibility of coronary microvascular abnormality

Reversible left ventricular wall motion abnormalities mimicking myocardial infarction have been reported in patients with a noncardiac illness. Their coronary angiograms do not demonstrate organic stenosis or epicardial coronary vasospasm. In this article, two cases of reversible left ventricular contraction abnormality are presented. Electrocardiography showed deep inverted T waves in precordial leads, and the echocardiography revealed diffuse akinesis of the apical region in the acute phase. Coronary angiography showed no significant stenosis or occlusion in either patient. Thallium scintigraphy showed no defect, while the metaiodobenzylguanidine scintigraphy demonstrated significant defects in the apex. The relative coronary flow reserve ratio, measured with an intracoronary Doppler flow wire, was significantly reduced in both patients. Myocardial contrast echocardiography revealed a reversible perfusion defect in the apex in the acute phase in case 2. Transiently impaired coronary microcirculation was thought to be involved in the pathogenesis of the reversible left ventricular dysfunction observed in these patients.

Long-term regulation of catecholamine formation by ouabain in cultured bovine adrenal chromaffin cells

The long-term effects of ouabain, an inhibitor of Na+/K+ -ATPase, on catecholamine formation in cultured bovine adrenal chromaffin cells were examined. The increase in [14C]catecholamine formation from [14C]tyrosine induced by ouabain was dependent on incubation time, and its maximal effect was observed after incubation for 8 h. The stimulatory effect of ouabain was concentration dependent (10-300 nM), causing maximal stimulation at 300 nM. The formation of [14C]catecholamines induced by ouabain was not increased by incubation with [14C]DOPA instead of [14C]tyrosine. Ouabain-induced [14C]catecholamine formation was influenced by decreases in extracellular Ca2+ concentration, but not by the presence of cycloheximide or actinomycin D. These results suggested that ouabain stimulates continuous activation of hydroxylation of tyrosine through a Ca2+ -dependent mechanism in cultured bovine adrenal chromaffin cells.

Determination of the levels of novel 31-amino acid endothelins and endothelins in human lungs

An effective method for determination of the levels of newly discovered 31-amino acid endothelins [ETs(1-31)] as well as big ETs and 21-amino acid ETs [ETs(1-21)], in human lungs has been developed. About 85% of ETs in human lung homogenates were recovered on acid extraction 8 times. Most of the published protocols for the determination of tissue ETs involve a reverse-phase minicolumn to separate proteins from peptides, after which the levels of ETs are directly determined by enzyme immunoassay. The levels determined, however, include fairly high amounts of non-bioactive ET metabolites in tissues and the data reported are diverse. We established an effective methods for the extraction and the separation of nine different muscle constricting ETs from their metabolites on a reverse-phase C18 column. Using this protocol, the levels of ETs in human lungs were determined by means of a sandwich-enzyme immunoassay specific for each ET derivative. The levels of ET-2(1-21) were the highest among those of ETs, and the levels of ETs(1-31) were in a similar range to those of big ETs but were lower than those of ETs(1-21). This method can be utilized to assess the pathophysiological roles of ETs(1-31) in various human organs.

Serotonin induces the expression of tissue factor and plasminogen activator inhibitor-1 in cultured rat aortic endothelial cells

Serotonin (5-hydroxytryptamine, or 5-HT), released from activated platelets, not only accelerates aggregation of platelets but also is known to promote mitosis, migration, and contraction of vascular smooth muscle cells (VSMCs). These effects are considered to contribute to thrombus formation and atherosclerosis. The aim of this study was to investigate the effects of 5-HT on the expressions of coagulative and fibrinolytic factors in rat aortic endothelial cells. Endothelial cells were stimulated with various concentrations of 5-HT (0.1 approximately 10 microM), and the expressions of tissue factor (TF), tissue factor pathway inhibitor (TFPI), plasminogen activator inhibitor-1 (PAI-1), and tissue-type plasminogen activator (TPA) messenger RNAs (mRNAs) were evaluated by Northern blot analysis. The activities of TF and PAI-1 were also measured. TF and PAI-1 mRNA were increased significantly in a concentration- and time-dependent manner. However, TFPI and TPA mRNA expression did not change. The inductions of TF and PAI-1 mRNAs were inhibited by a 5-HT1/5-HT2 receptor antagonist (methiothepin) and a selective 5-HT2A receptor antagonist (MCI-9042). These results indicate that 5-HT increases procoagulant activity and reduces fibrinolytic activities of endothelial cells through the 5-HT2A receptor. It was concluded that the modulation of procoagulant and hypofibrinolytic activities of endothelial cells by 5-HT synergistically promotes thrombus formation at the site of vessel injury with the platelet aggregation, VSMC contraction, and VSMC proliferation.

Profiles of herpes simplex virus type 1 antibodies in primary herpetic infections of the maxillofacial regions

Changes in the aspects of primary infection of herpes simplex virus type 1 in the maxillofacial region have been observed due to the increase in the number of adult cases. To elucidate the possibility of serologic diagnosis in primary infectious patients and the influence of virucide on antibody production, we evaluated changes in serum antibodies (neutralizing antibody, IgM, and IgG antibody) in pair serum in 35 primary infectious patients using a micro-plate method and ELISA. At the first examination, 31 (89%) of 35 patients did not have neutralizing antibodies, and 23 of the 31 patients showed significant increases of neutralizing antibody titer more than four times at the second examination. Three of the 4 patients that had neutralizing antibodies showed significant increases at the second examination; therefore, 26 (74.3%) of the 35 patients could be diagnosed as having primary infection only by neutralizing antibodies. Regarding 9 patients who did not show significant increases in neutralizing antibodies, 5 of the 9 patients showed increases in IgG antibody titer more than two times at the second examination, and at the first examination, IgM antibody titer in 3 of the remaining 4 patients was more than 0.2 that is the cut-off value; therefore, it was possible to diagnose the 8 patients as having primary infection. We evaluated the influence of the use of virucide, gender, age, period between onset and the first examination, and period between onset and the second blood collection on antibody production; however, there were no differences observed except that significant increases in antibody were observed in 4 children aged below 10 years, although they used virucide. These results revealed that it was not possible to serologically diagnose whether there was primary or recurrent infection only by neutralizing antibody titer.

Estrogen prevents oxidative stress-induced endothelial cell apoptosis in rats

BACKGROUND

Estrogen replacement attenuates the increased risk of cardiovascular disease in postmenopausal women. Recent studies using an in vitro culture system have shown that estrogen inhibits endothelial cell (EC) apoptosis. The in vivo relevance of this finding, however, is not defined. To do so, we have developed a rat vascular injury model in which EC apoptosis induced by hydrogen peroxide plays a role.

METHODS AND RESULTS

Intracarotid arterial administration of 0.01 mmol/L hydrogen peroxide for 5 minutes evoked EC apoptosis after 6 to 24 hours, determined by nuclear staining with Hoechst 33342, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling, and electron microscopy. Apoptosis was associated with EC loss and was followed by EC regeneration at 72 hours and neointima formation at 1 to 2 weeks. Estradiol replacement in ovariectomized female Wistar rats decreased the rate of apoptotic ECs by approximately 50%, assayed by nuclear morphology of en face specimens, resulting in increased remaining ECs and decreased neointima formation. Progesterone did not influence the effects of estradiol on EC apoptosis.

CONCLUSIONS

These results provide new insight into the cardioprotective action of estrogen as well as a paradigm of the response-to-injury hypothesis.

Signal transduction of reactive oxygen species and mitogen-activated protein kinases in cardiovascular disease

Reactive oxygen species (ROS), generated by reduction-oxidation (redox) reactions, have been recognized as important chemical mediators that regulate signal transduction. It has been reported that increase in ROS generation may relate to a risk for cardiovascular diseases such as atherosclerosis, angina pectoris, and myocardial infarction. Therefore, understanding the ROS-generating biological processes and ROS-induced intracellular signaling will be informative to gain insights into the pathogenesis of these diseases. In this review, we focus on the sources and reactions of ROS in the cardiovascular system and the role of mitogen-activated protein (MAP) kinase pathway in redox-mediated signal transduction. Clinical implications of ROS and MAP kinase are then described to provide insight into the pathogenesis of various redox-sensitive cardiovascular diseases. The pathways responsible for ROS generation in the cardiovascular system may provide novel therapeutic targets.

Effect of endothelin-1(1-31) on p38 mitogen-activated protein kinase in cultured human mesangial cells

It was reported that human chymase cleaves big endothelins (ETs) at the Tyr31-Gly32 bond and produces 31-amino acid ETs(1-31). In this study, we investigated the effect of ET-1(1-31) on p38 mitogen-activated protein kinase (p38-MAPK) activity in human mesangial cells (HMCs). By measuring the kinase activity, we demonstrated that ET-1 (1-31) activated the p38-MAPK dose-dependently (10(-9) M to 10(-7) M), which was inhibited by SB203580. The p38-MAPK activation induced by ET-1(1-31) peaked at 10 minutes. BQ123 almost abolished ET-1(1-31)-induced p38-MAPK activation, whereas BQ788 failed to inhibit it. These findings suggest that the stimulatory effect of ET-1(1-31) on p38-MAPK activation is mediated through ET(A) or ET(A)-like receptor. In conclusion, ET-1(1-31) induced increase in p38-MAPK activation in cultured HMCs.

Cyclin A downregulation and p21(cip1) upregulation correlate with GATA-6-induced growth arrest in glomerular mesangial cells

The GATA-6 transcription factor is reported to be expressed in vascular myocytes. Because glomerular mesangial cells (GMCs) and vascular myocytes have similar properties, we examined whether GATA-6 was expressed in cultured GMCs and whether overexpression of GATA-6 induced cell cycle arrest in GMCs, using a recombinant adenovirus that expresses GATA-6 (Ad GATA-6). GATA-6 expression in GMCs was downregulated when quiescent GMCs were stimulated by serum to reenter the cell cycle. [(3)H]thymidine uptake was inhibited in GMCs infected with Ad GATA-6 in a dose- and time-dependent manner. The expression of cyclin A protein was decreased and that of the cyclin-dependent kinase inhibitor p21(cip1) was increased in GMCs infected with Ad GATA-6. Although the expression of p21(cip1) transcripts did not change remarkably, p21(cip1) protein was stabilized in GMCs infected with Ad GATA-6, suggesting a post-transcriptional regulation of p21(cip1) expression. Northern blot analysis showed that expression of the cyclin A transcript was decreased in Ad GATA-6-infected cells, whereas this decrease of cyclin A was not observed in GMCs derived from p21(cip1) null mice. Our results demonstrate that GATA-6 is endogenously expressed in GMCs and that overexpression of GATA-6 can induce cell cycle arrest. Our results also show that GATA-6-induced cell cycle arrest is associated with inhibition of cyclin A expression and p21(cip1) upregulation. Finally, our results indicate that the GATA-6-induced suppression of cyclin A expression depends on the presence of p21(cip1).

Effect of endothelin-1 (1-31) on human mesangial cell proliferation

It was previously found that human chymase cleaves big endothelins (ETs) at the Tyr31-Gly32 bond and produces 31-amino acid ETs (1-31). In the present study, human plasma concentrations of ET-1 (1-31) and ET-1 were examined and the effect of synthetic ET-1 (1-31) on the proliferation of cultured human mesangial cells (HMCs) was investigated. The proliferative effect of ET-1 (1-31) was evaluated from the [3H]-thymidine uptake. The activity of extracellular signal-regulated kinase (ERK) and DNA binding activity of activator protein-1 were determined by using an in-gel kinase assay and gel mobility shift assay, respectively. Immunoreactive ET-1 (1-31) was detectable in plasma, but the level was slightly lower than that of ET-1. ET-1 (1-31) increased [3H]-thymidine incorporation in HMCs to a degree similar to that induced by ET-1. ET-1 (1-31) also activated ERK1/2. Inhibition of protein kinase C and ERK kinase caused a reduction of ET-1 (1-31)-induced ERK1/2 activation. The ERK1/2 activation was followed by an increase in transcription factor activator protein-1 DNA binding activity. These findings suggest that ET-1 (1-31) is a bioactive peptide in humans and ET-1 (1-31) itself stimulates HMC proliferation.

Pericardial constriction due to malignant lymphoma

We experienced a case of T-cell lymphoma demonstrating diastolic heart failure as an initial manifestation. An 81-year-old Japanese male was admitted to the University of Tokyo Hospital because of progressive dyspnea and general fatigue. Clinical presentation was congestive heart failure and cervical lymphadenopathy. Right heart catheterization revealed "dip and plateau" waveforms in right ventricular pressure, which suggested a constrictive nature of heart failure. Gallium scintigram showed marked uptake in the heart. Biopsy from a cervical lymph node confirmed the diagnosis of malignant lymphoma of T-cell origin. Diastolic heart failure remained after successful chemotherapy. Autopsy revealed pericarditis with severe adhesion of the pericardium and the epicardium.

Association of coronary risk factors and endothelium-dependent flow-mediated dilatation of the brachial artery

Impaired endothelial function has been reported to be the initial step in atherosclerosis. Some coronary risk factors independently relate to impaired endothelial function. However, few studies have examined the association between coronary risk factors and endothelial function in patients who have multiple risk factors without clinical atherosclerosis. This study was undertaken to elucidate the relationship between accumulation of coronary risk factors and vascular endothelial dysfunction. We examined 101 subjects with one or more coronary risk factors 56.8 +/- 1.0 years old and 40 age-matched control subjects without coronary risk factors. We measured brachial artery diameter non-invasively using a 7.5-MHz ultrasound machine at rest, during reactive hyperemia caused by endothelium-dependent vasodilatation, and after sublingual administration of nitroglycerin, which causes endothelium-independent vasodilatation. The percentage change in flow-mediated diameter (%FMD; deltaD/D x 100), in subjects with one or more coronary risk factors was significantly lower than that in control subjects(4.8 +/- 0.3% vs. 6.7 +/- 0.5%, p < 0.01). Endothelium-independent vasodilatation by nitroglycerin did not differ between the two groups. Endothelial function was impaired according to the accumulation of coronary risk factors. On multiple regression analysis, the number of risk factors, age, and brachial artery diameter at rest showed significant correlation with %FMD. Our results suggest that an accumulation of coronary risk factors was significantly related to impairment of endothelial function.

Src and Cas mediate JNK activation but not ERK1/2 and p38 kinases by reactive oxygen species

c-Jun NH(2)-terminal kinase (JNK) is activated by a number of cellular stimuli such as inflammatory cytokines and environmental stresses. Reactive oxygen species also cause activation of JNK; however, the signaling cascade that leads to JNK activation remains to be elucidated. Because recent reports showed that expression of Cas, a putative Src substrate, stimulates JNK activation, we hypothesized that the Src kinase family and Cas would be involved in JNK activation by reactive oxygen species. An essential role for both Src and Cas was demonstrated. First, the specific Src family tyrosine kinase inhibitor, PP2, inhibited JNK activation by H(2)O(2) in a concentration-dependent manner but had no effect on extracellular signal-regulated kinases 1 and 2 and p38 activation. Second, JNK activation in response to H(2)O(2) was completely inhibited in cells derived from transgenic mice deficient in Src but not Fyn. Third, expression of a dominant negative mutant of Cas prevented H(2)O(2)-mediated JNK activation but had no effect on extracellular signal-regulated kinases 1 and 2 and p38 activation. Finally, the importance of Src was further supported by the inhibition of both H(2)O(2)-mediated Cas tyrosine phosphorylation and Cas.Crk complex formation in Src-/- but not Fyn-/- cells. These results demonstrate an essential role for Src and Cas in H(2)O(2)-mediated activation of JNK and suggest a new redox-sensitive pathway for JNK activation mediated by Src.

Red wine polyphenols inhibit proliferation of vascular smooth muscle cells and downregulate expression of cyclin A gene

BACKGROUND

Red wine polyphenols have been shown to contribute to the "French paradox" phenomenon, which consists of lower morbidity and mortality from coronary heart disease in the French population. Although vascular smooth muscle cell (VSMC) proliferation plays an important role in the progression of atherosclerotic lesions, the effects of red wine polyphenols on VSMC proliferation have not been elucidated.

METHODS AND RESULTS

We extracted the total polyphenolic fraction from red wine (RW-PF) by column chromatography. Treatment with RW-PF showed a potent inhibitory effect on the proliferation and DNA synthesis of cultured rat aortic smooth muscle cells (RASMCs). In contrast, the inhibitory effect of RW-PF on the proliferation of bovine carotid endothelial cells was observed only at much higher concentrations. To elucidate the molecular mechanisms of this antiproliferative effect of RW-PF on RASMCs, we investigated the effects of RW-PF on cell cycle regulation. RW-PF downregulated the expression of cyclin A mRNA and cyclin A promoter activity. In addition, RW-PF decreased the binding of nuclear proteins to the activating transcription factor (ATF) site in the cyclin A promoter and downregulated the mRNA levels of transcription factors, cAMP-responsive element-binding protein (CREB), and ATF-1.

CONCLUSIONS

These results suggest that the downregulation of cyclin A gene expression may contribute to the antiproliferative effect of red wine polyphenols on RASMCs through the inhibition of transcription factor expression.

Prostanoids regulate proliferation of vascular smooth muscle cells induced by arginine vasopressin

The aim of the present study was to investigate the effect of arginine [Arg(8)]vasopressin (vasopressin) on proliferation of vascular smooth muscle cells and the mechanisms underlying the action of vasopressin. To clarify these issues, we used two different types of vascular smooth muscle cells, cultured adult rat aortic smooth muscle cells and A10 cells, a cell line derived from fetal rat aorta. Vasopressin (10(-8) to 10(-6) M) significantly stimulated the proliferation of rat aortic smooth muscle cells in a dose-dependent manner. In contrast, vasopressin significantly inhibited the proliferation of A10 cells. This inhibition was abolished when A10 cells were treated with indomethacin. Vasopressin stimulated the production of prostanoids several-fold in A10 cells but not in rat aortic smooth muscle cells. These effects were completely blocked by the vasopressin V(1) receptor antagonist, 1-¿1-[4-(3-acetylamino-propoxy)benzoyl]4-piperidyl¿-3, 4-dihydro-2(1H)-quinolinone (OPC21268), but not by the vasopressin V(2) receptor antagonist, (+/-)-5-dimethylamino-1-[4-(2-methylbenzoylamino)benzol]-2, 3,4,5-tetrahydro-1H-benzazepine hydrochloride (OPC31260). These results indicate that vasopressin has diverse effect on proliferation of vascular smooth muscle cells through the vasopressin V(1) receptor, depending on the production of growth regulatory prostanoids.