永井 良三

Solid tumors require neovascularization for their growth. Recent evidence indicates that bone marrow-derived endothelial progenitor cells (EPCs) contribute to tumor angiogenesis. We show here that granulocyte colony-stimulating factor (G-CSF) markedly promotes growth of the colon cancer inoculated into the subcutaneous space of mice, whereas G-CSF had no effect on cancer cell proliferation in vitro. The accelerated tumor growth was associated with enhancement of neovascularization in the tumor. We found that bone marrow-derived cells participated in new blood vessel formation in tumor. Our findings suggest that G-CSF may have potential to promote tumor growth, at least in part, by stimulating angiogenesis in which bone marrow-derived EPCs play a role.

Obesity is more linked to vascular disease, including atherosclerosis and restenotic change, after balloon angioplasty. The precise mechanism linking obesity and vascular disease is still unclear. Previously we have demonstrated that the plasma levels of adiponectin, an adipose-derived hormone, decreases in obese subjects, and that hypoadiponectinemia is associated to ischemic heart disease. In current the study, we investigated the in vivo role of adiponectin on the neointimal thickening after artery injury using adiponectin-deficient mice and adiponectin-producing adenovirus. Adiponectin-deficient mice showed severe neointimal thickening and increased proliferation of vascular smooth muscle cells in mechanically injured arteries. Adenovirus-mediated supplement of adiponectin attenuated neointimal proliferation. In cultured smooth muscle cells, adiponectin attenuated DNA synthesis induced by growth factors including platelet-derived growth factor, heparin-binding epidermal growth factor (EGF)-like growth factor (HB-EGF), basic fibroblast growth factor, and EGF and cell proliferation and migration induced by HB-EGF. In cultured endothelial cells, adiponectin attenuated HB-EGF expression stimulated by tumor necrosis factor a. The current study suggests an adipo-vascular axis, a direct link between fat and artery. A therapeutic strategy to increase plasma adiponectin should be useful in preventing vascular restenosis after angioplasty.

Objective-Heme oxygenase (HO) is important in the defense against oxidative stress and as a factor in an antiatherogenic mechanism. Compared with long (GT)(n) repeats, short (GT)(n) repeats in the human HO-1 gene promoter were shown to have higher transcriptional activity in response to oxidative stress. There is a strong link between oxidative stress and the pathogenesis of coronary artery disease (CAD). Methods and Results-We screened the allelic frequencies of (GT)(n) repeats in the HO- 1. gene promoter in 577 patients who underwent coronary angiography. Because the distribution of numbers of (GT)(n) repeats was bimodal, we divided the alleles into 2 subclasses: class S included shorter (<27) repeats, and class L included longer ( ≥ 27) repeats. Multivariate logistic regression models including standard coronary risk factors revealed that the genotypes were significantly related to CAD status in hypercholesterolemic, diabetic patients or in smokers. In this study, the patients with shorter GT repeats were less likely to have CAD. Conclusions-Length polymorphism in the HO-1 gene promoter is related to CAD susceptibility in Japanese people who also have coronary risk factors such as hypercholesterolemia, diabetes, and smoking. HO-1 may play an antiatherogenic role in Japanese patients with these coronary risk factors.

Background-Abnormal iron deposition may cause oxidant-induced damage in various organs. We have previously reported that continuous administration of angiotensin II to rats results in an overt iron deposition in the renal tubular epithelial cells, which may have a role in angiotensin II-induced renal damage. In the present study, we investigated the role of iron in the development of cardiac injury induced by angiotensin II. Methods and Results-Angiotensin II was continuously infused to rats at a dose of 0.7 mg/kg per day for 7 consecutive days. No iron deposits were observed in the hearts of untreated rats, whereas iron deposition was seen in the cells in the subepicardial and granulation regions after angiotensin II infusion. Concomitant administration of deferoxamine, an iron chelator, significantly reduced the extent of cardiac fibrosis, which suggests that iron deposition aggravates the cardiac fibrosis induced by angiotensin II. Iron overload caused by the administration of iron-dextran resulted in an augmentation of cardiac fibrosis and the generation of neointimal cells in the coronary artery in angiotensin II-infused rats. By contrast, neointima was not formed in the cardiac vessels in norepinephrine-infused rats with iron overload. Conclusions-Cardiac iron deposition may be involved in the development of cardiac fibrosis induced by angiotensin II. In addition, iron overload may enhance the formation of neointima under conditions of increased circulating angiotensin II but not catecholamines.

Peroxisome proliferator-activated receptor gamma (PPARgamma), a member of a nuclear transcription factor family, has been previously demonstrated to have antiinflammatory activity. The effects of PPARgamma activation in the development of an immune response are less well characterized. Through evaluation of PPARgamma heterozygote mice (PPARgamma(+/-) and specific PPARgamma agonist ligand binding, we evaluated the immunologic effects of PPARgamma activation in a well-described model of colitis. Increased susceptibility to dextran sodium sulfate (DSS)-induced colitis as defined by body weights, histologic injury, and survival was observed in the PPARgamma(+/-) mice in comparison to wild-type mice. Three different PPARgamma ligands (troglitazone, pioglitazone, and rosiglitazone) demonstrated beneficial dose-related treatment effects when administered prior to the onset of colitis. However, no protection was observed when PPARgamma ligand activation occurred after the onset of colitis. The reduction in DSS-induced inflammation noted with PPARgamma ligand treatment was associated with decreased interferon-gamma and tumor necrosis factor-alpha and increased interleukin (IL)-4 and IL- 10 levels as assessed by quantitative reverse transcriptase-polymerase chain reaction. Consistent with this shift towards a T helper (Th2) cytokine dominance, PPARgamma ligand treatment stimulated increased GATA-3 expression. These results indicate that the protective effects exhibited by PPARgamma ligands in intestinal inflammation may be due to immune deviation away from Th1 and towards Th2 cytokine production.

The Klotho mouse is a recently developed model that exhibits phenotypes resembling human aging. We used this model to investigate sensorineural hearing loss from the point of view that it may be considered an issue of aging. Using reverse transcription-polymerase chain reaction, Western blotting and immunohistochemical staining, we were able to confirm klotho gene transcription and protein synthesis in the kidney and inner ear. Klotho protein was mainly expressed in the stria vascularis and spiral ligament of the inner ear and in the distal convoluted tubule of the kidney, likely serving a common function in the two organs, i.e., modulating ion transport. The threshold for the auditory brainstem response was significantly higher in Klotho mice than in wild-type mice, and wave I latencies were prolonged. On the other hand, Klotho mice exhibited a normal distribution of I-IV interpeak intervals. No obvious morphological abnormalities were detected in Klotho mice, although no expression of Klotho protein was detected, and there was an apparent hearing disorder. Taken together, these findings suggest that by contributing to the maintenance ion homeostasis in the endolymph, Klotho protein serves as a key mediator of auditory function.

In an attempt to find a strategy to modulate the proliferation of vascular endothelial cells, we examined whether constitutive activation of proto-oncogen protein p21 (Ras) induced the reentry of confluent human umbilical vascular endothelial cells (HUVECs) into the S phase. When an adenovirus construct expressing a constitutively active Ras mutant (Ad/RasG12V) was infected into HUVECs, their morphology changed strikingly and they appeared to be transformed. However, Ad/RasG12V-infected HUVECs did not enter the S phase, as determined by assessing 3H-thymidine incorporation. In accordance with the above results, the expression of cyclin A both at the transcript and protein levels did not increase in Ad/RasG12V-infected HUVECs relative to that in control cells, although the expression of cyclin D1 was induced in Ad/RasG12V-infected cells. Interestingly, the expression of the cyclin-dependent kinase (CDK) inhibitor p21cip1 was remarkably increased while that of p27kip1 did not decrease in Ad/RasG12V-infected HUVECs. Furthermore, CDK2 activity was not induced in Ad/RasG12V-infected HUVECs. These results suggested that the constitutive activation of Ras promoted the reentry of confluent HUVECs in the G0 phase into the G1 phase, but not into the S phase. The results also indicated that the constitutive activation of Ras might have induced the persistent expression of p21cip1 and p27kip1, and that this induction of p21cip1 and p27kip1 expression possibly caused the cell cycle arrest at the G1 phase.

OBJECTIVE: N-(3'4'-dimethoxycinnamoyl)-anthranilic acid (tranilast) is a drug that has been shown to reduce the incidence of restenosis after angioplasty in middle-scale clinical trials. Despite clinical interest in this drug, the pharmacological actions of tranilast remain relatively unexplored at a molecular level. METHODS AND RESULTS: We evaluated the effects of tranilast on vascular smooth muscle cell (VSMC) proliferation in wild-type mice and in mice lacking a cyclin-dependent kinase inhibitor, p21(WAF1) (p21). Tranilast potently inhibited the proliferation of VSMC cultures derived from wild-type mice, but VSMCs derived from p21-deficient (p21-/-) mice were unaffected by this treatment. In a mouse femoral artery model of vascular injury, tranilast administration to wild-type mice led to an upregulation of p21 expression and a decrease in the number of proliferating VSMCs, as determined by immunostaining for proliferating cell nuclear antigen. In contrast, tranilast had no effect on the number of proliferating cell nuclear antigen-positive cells in the injured arteries of p21-/- mice. Administration of tranilast significantly reduced the neointimal VSMC hyperplasia in wild-type mice at 4 weeks but had no effect on lesion formation in p21-/- mice. CONCLUSIONS: Our findings provide genetic evidence that tranilast inhibits intimal hyperplasia via a p21-dependent pathway, an activity that may contribute to its efficacy in the prophylactic treatment of postangioplasty restenosis.

Cholesterol ester (CE)-laden foam cells are a hallmark of atherosclerosis. To determine whether stimulation of the hydrolysis of cytosolic CE can be used as a novel therapeutic modality of atherosclerosis, we overexpressed hormone-sensitive lipase (HSL) in THP-1 macrophage-like cells by adenovirus-mediated gene delivery, and we examined its effects on the cellular cholesterol trafficking. We show here that the overexpression of HSL robustly increased neutral CE hydrolase activity and completely eliminated CE in the cells that had been preloaded with CE by incubation with acetylated low density lipoprotein. In these cells, cholesterol efflux was stimulated in the absence or presence of high density lipoproteins, which might be at least partially explained by the increase in the expression of ABCA1 Importantly, these effects were achieved without the addition of acyl-CoA:cholesterol acyltransferase inhibitor, cAMP, or even high density lipoproteins. Furthermore, the uptake and degradation of acetylated low density lipoprotein was significantly reduced probably by decreased expression of scavenger receptor A and CD36. Notably, the cells with stimulated CE hydrolysis did not exhibit either buildup of free cholesterol or cytotoxicity. In conclusion, increased hydrolysis of CE by the overexpression of HSL leads to complete elimination of CE from THP-1 foam cells not only by increasing efflux but also by decreasing influx of cholesterol.

Elucidating molecular mechanisms that regulate induction of cardiomyocyte differentiation is important because it may lead to practical therapeutic application for tissue regeneration in various heart diseases. Recent studies have demonstrated that some growth factors regulate expression of cardiac transcription factors and play a pivotal role in cardiac development. This study investigated the roles of bone morphogenetic proteins (BMPs) and their downstream molecules, using P19CL6 cardiomyogenic cell lines. Several lines of evidence show that BMPs are indispensable for cardiomyocyte differentiation and induce differentiation through two cardiac transcription factors, Csx/Nkx2-5 and GATA-4. Furthermore, it was demonstrated that not only Smads and TAK1, important mediators of transforming growth factor-beta signaling, but also their common target, ATF-2 transcription factor, play a critical role in cardiomyocyte differentiation. (C) 2002, Elsevier Science Inc.

OBJECTIVE: Several in vitro studies have implicated that adrenomedullin (AM) plays an important role in the pathogenesis of vascular injury and fatty streak formation. To test this possibility in vivo, we evaluated 2 experimental models using transgenic mice overexpressing AM in a vessel-selective manner (AMTg mice). METHODS AND RESULTS: Placement of a periarterial cuff on femoral arteries resulted in neointimal formation at 2 to 4 weeks to a lesser extent in AMTg mice than in their wild-type littermates (at 28 days, intima/media area ratio 0.45+/-0.14 versus 1.31+/-0.41, respectively; P<0.001). This vasculoprotective effect observed in AMTg mice was inhibited by N(omega)-nitro-L-arginine methyl ester. We further examined the effect of AM on hypercholesterolemia-induced fatty streak formation by crossing AMTg mice with apolipoprotein E knockout mice (ApoEKO mice). The extent of the formation of fatty streak lesions was significantly less in ApoEKO/AMTg mice than in ApoEKO mice (percent lesion area 12.0+/-3.9% versus 15.8+/-2.8%, respectively; P<0.05). Moreover, endothelium-dependent vasodilatation as indicative of NO production was superior in AMTg/ApoEKO mice compared with ApoEKO mice. CONCLUSIONS: Taken together, our data demonstrated that AM possesses a vasculoprotective effect in vivo, which is at least partially mediated by NO.

The adipocyte-derived hormone adiponectin has been proposed to play important roles in the regulation of energy homeostasis and insulin sensitivity, and it has been reported to exhibit putative antiatherogenic properties in vitro. In this study we generated adiponectin-deficient mice to directly investigate whether adiponectin has a physiological protective role against diabetes and atherosclerosis in vivo. Heterozygous adiponectin-deficient (adipo(+/-)) mice showed mild insulin resistance, while homozygous adiponectin-deficient (adipo(-/-)) mice showed moderate insulin resistance with glucose intolerance despite body weight gain similar to that of wild-type mice. Moreover, adipo(-/-) mice showed 2-fold more neointimal formation in response to external vascular cuff injury than wild-type mice (p = 0.01). This study provides the first direct evidence that adiponectin plays a protective role against insulin resistance and atherosclerosis in vivo.

Mutations of either PKD1 or PKD2 are associated with autosomal dominant polycystic kidney disease (ADPKD). The molecular function of the gene product of PKD1, polycystin-1, in vitro has been elucidated recently, but the molecular pathological consequences of the loss of polycystin-1 in vivo have remained unclear. We have generated a mouse with a targeted deletion of exons 2-6 of Pkd1 to study the molecular defects in Pkd1 mutants. Homozygote embryos (Pkd1(-/-)) developed hydrops, cardiac conotruncal defects and renal cystogenesis. Total protein levels of beta-catenin in heart and kidney and c-MYC in heart were decreased in Pkd1(-/-) embryos. In the kidneys of Pkd1(-/-), the expression of E-cadherin and PECAM in basolateral membranes of renal tubules was attenuated, and tyrosine phosphorylation of epidermal growth factor receptor and Gab1 were constitutively enhanced when cystogenesis started on embryonic day (E) 15.5-16.5. Maternally administered pioglitazone, a thiazolidinedione compound, resolved these molecular defects of Pkd1(-/-). Treatment with pioglitazone improved survival of Pkd1(-/-) embryos and ameliorated the cardiac defects and the degree of renal cystogenesis. Long-term treatment with pioglitazone improved the endothelial function of adult Pkd1(+/-). These data indicated that molecular defects observed in Pkd1(-/-) embryos contributed to the pathogenesis of ADPKD and that thiazolidinediones had a compensatory effect on the pathway affected by the loss of polycystin-1. Pathways activated by thiazolidinediones may provide new therapeutic targets in ADPKD.

OBJECTIVES: To examine the diagnostic performance of circulating oxidized low density lipoprotein levels as a biochemical risk marker of coronary heart disease. DESIGN AND METHODS: 361 patients with coronary artery disease and 710 healthy volunteers as normal controls were examined. Receiver-operating characteristics curve analysis in addition to statistical analysis (univariate, multivariate) were done to determine the usefulness of the assay. RESULTS: Patients with coronary artery disease showed significantly elevated circulating oxidized low density lipoprotein levels. Males less than 70 years of age showed a significant association between oxidized low density lipoprotein levels and coronary artery disease. Receiver-operating characteristics curve analysis showed superior performance (e.g., sensitivity, specificity) of oxidized low density lipoprotein as a diagnostic marker of coronary artery disease as compared against other lipid markers (total cholesterol, triglyceride, high density lipoprotein, lipoprotein (a), and total cholesterol to high density lipoprotein ratio) with optimal performance in younger males. CONCLUSIONS: Oxidized low density lipoprotein levels may be a promising biochemical risk marker of atherosclerotic disease, especially in young males.

We isolated a mammalian gene whose expression transiently increased in response to intimal denudation of rabbit aorta. It was identical to a gene encoding a zinc transporter, ZNT5, reported very recently by others. Mice deficient for this gene showed poor growth and a decrease in bone density due to impairment of osteoblast maturation to osteocyte. More than 60% of male null mice died suddenly because of the bradyarrhythmias. Analysis of gene-expression profiles in murine hearts by means of an oligonucleotide microarray disclosed that a subset of genes encoding immediate-early response factors (IEGs) and heat shock proteins (HSPs) were down-regulated in Znt5-null mice. These results indicate that Znt5 protein plays an important role in maturation of osteoblasts and in maintenance of the cells involved in the cardiac conduction system, partly owing to dysregulated expression of IEGs and HSPs.

Csx/Nkx2-5, which is essential for cardiac development of the embryo, is abundantly expressed in the adult heart. We here examined the role of Csx/Nkx2-5 in the adult heart using two kinds of transgenic mice. Transgenic mice that overexpress a dominant negative mutant of Csx/Nkx2-5 (DN-TG mice) showed degeneration of cardiac myocytes and impairment of cardiac function. Doxorubicin induced more marked cardiac dysfunction in DN-TG mice and less in transgenic mice that overexpress wild type Csx/Nkx2-5 (WT-TG mice) compared with non-transgenic mice. Doxorubicin induced cardiomyocyte apoptosis, and the number of apoptotic cardiomyocytes was high in the order of DN-TG mice, non-transgenic mice, and WT-TG mice. Overexpression of the dominant negative mutant of Csx/Nkx2-5 induced apoptosis in cultured cardiomyocytes, while expression of wild type Csx/Nkx2-5 protected cardiomyocytes from doxorubicin-induced apoptotic death. These results suggest that Csx/Nkx2-5 plays a critical role in maintaining highly differentiated cardiac phenotype and in protecting the heart from stresses including doxorubicin.

Fas ligand (FasL) is a death factor that induces apoptosis in cells bearing its receptor, Fas. Accumulating evidence indicates that the Fas/FasL system is involved not only in apoptosis but also in cell-activation signals. Recently, it was reported that local stimulation of Fas in vivo using an agonistic antibody triggers inflammatory cell infiltration and neoangiogenesis independently of apoptosis. On the other hand, Fas/FasL interaction has been proposed to control the growth and development of new subretinal vessels. Here, we evaluated the potential involvement of Fas/FasL interaction in collateral development in response to tissue ischemia. Hindlimb ischemia was induced in C57BL/6J (wild-type), B6-gld(FasL -/-), and B6-lpr(Fas -/-) mice by resection of the right femoral artery. The blood flow recovery of FasL -/- or Fas -/- mice was similar to that of wild-type mice, as determined using a laser Doppler imaging system. There was no significant difference in capillary density of the ischemic calf muscle among the mice, as determined by anti-CD31 immunostaining. We did not find any difference in the number of infiltrating inflammatory cells or in vascular endothelial growth factor expression. These results indicate that postnatal angiogenesis in response to acute ischemia can occur independently of the endogenous Fas/FasL interaction.

Lipopolysaccharide (LPS) has a profound effect on cardiac performance through a collapse of the vasculature. In this study, we determined whether LPS has a direct effect on the cardiac myocytes by examining the expression of the BNP gene in cultured neonatal rat cardiac myocytes. Northern blot analysis showed that LPS induces the expression of the BNP gene. Time-course experiments revealed that BNP mRNA levels were increased 1 h after LPS stimulation. Enhanced induction of BNP was observed 3 h after stimulation when expression of CD14, a specific receptor for LPS, was markedly induced. LPS-mediated BNP expression was completely inhibited by the pretreatment of SB203580, a specific inhibitor for p38 MAPK as well as by genistein, a broad range tyrosine kinase inhibitor. In accordance with these results, LPS increases phosphorylation of p38 mitogen-activated protein kinase (MAPK). Transient transfection assays revealed that low dose (1 ng/ml) of LPS induces the luciferase activity derived from the construct containing the BNP promoter spanning from -1000 and +80 in front of the luciferase gene. Cotransfection of the expression vectors for constitutive active forms of Rac1, MKK3 and p38 MAPK significantly increased BNP promoter activity. Mutation of the GATA sequence located at -95 and -84 abolished such an induction of BNP promoter activity. Overexpression of CD14 enhanced the LPS's effect on BNP promoter. These results indicate that LPS induces the BNP gene expression through a pathway involving CD14, Rac1, p38 MAPK and GATA elements. In addition to the induction of BNP expression by hemodynamic overload, our data suggest that elevated levels of BNP under the endotoxemic condition is partly mediated through the increased expression of CD14, which lies upstream of the Rac1-p38 MAPK pathway.

The homeobox transcription factor CSX/NKX2.5, which is a vertebrate homologue of the Drosophila gene tinman, is essential for cardiac development. It is expressed in the early cardiac mesoderm and in heart muscle lineage throughout life. Homozygous deletion of CSX/NKX2.5 causes early embryonic lethality in mice because cardiac development is arrested at the linear heart tube stage. Heterozygous mutation of human CSX/NKX2.5 has been associated with various congenital heart diseases such as atrial septal defect (ASD), ventricular septal defect, tetralogy of Fallot, and tricuspid valve abnormalities, including Ebstein's anomaly. Additionally, CSX/NKX2.5 mutation causes atrioventricular (AV) conduction block with or without associated congenital heart diseases. Ten different heterozygous mutations have been already reported and a new point mutation, which is a C-to-A transition (Cys264ter) at nucleotide 901 of CSX/NKX2.5, results in the production of a truncated protein occurring COOH-terminal to the homeodomain of CSX/NKX2.5. The mutation was found in a patient with familial ASD and first-degree AV block; 4 members from 3 generations had secundum-type ASD and first-degree AV block.

Many studies have indicated that oxidative stress induces apoptosis in cardiomyocytes, but its mechanism remains unknown. We examined whether tumor necrosis factor-alpha (TNF-alpha) is involved in oxidative stress-induced cardiomyocyte apoptosis. Pretreatment with anti-TNF-alpha antibody significantly decreased the number of H(2)O(2)-induced TUNEL-positive cardiomyocytes. Expression of TNF-alpha gene was upregulated by H(2)O(2), and H(2)O(2) mildly but significantly increased the concentration of TNF-alpha in the culture medium. Although neither low dose of H(2)O(2) nor TNF-alpha induced apoptosis, stimulation with H(2)O(2) and TNF-alpha synergistically increased apoptosis. These results suggest that oxidative stress induces apoptosis of cardiac myocytes partly through TNF-alpha.

It is well known that angiotensin II (Ang II) is implicated in the phenotypic modulation and hypertrophy of vascular smooth muscle cells (VSMCs). To study the mechanisms by which Ang II contributes to the pathological changes of VSMCs, we examined whether Ang II stimulated myocyte enhancer factor 2 (MEF2)- and calcineurin/nuclear factor of activated T cell (NFAT)-dependent transcriptional activation of genes in VSMCs. Ang II increased the DNA binding activity of MEF2A and its expression at the protein level. Ang II induced c-jun promoter activity, and this increase was inhibited by dominant-negative mutants of MEF2A and mitogen-activated protein kinase kinase 6 but not by calcineurin inhibitors. Ang II stimulated NFAT DNA binding activity and NFAT-dependent gene transcription, and these effects of Ang II were inhibited by calcineurin inhibitors. Furthermore, Ang II induced the promoter activity of the nonmuscle-type myosin heavy chain B gene, which we used as a marker of the dedifferentiated state of VSMCs, and this increase was inhibited by calcineurin inhibitors but not by the dominant-negative mutants of MEF2A or mitogen-activated protein kinase kinase 6. Finally, Ang II increased protein synthesis, and this increase was inhibited by infection with an adenovirus construct that expresses the dominant-negative mutant of MEF2A but not by calcineurin inhibitors. These results suggest that Ang II stimulates the MEF2- and calcineurin/NFAT-dependent pathways and that these pathways have distinct roles in VSMCs.

Background: T-cell-mediated myocardial damage is known to be involved in acute myocarditis and dilated cardiomyopathy. Recently, we found that tumor necrosis factor (TNF) ligand superfamily costimulatory molecules, especially 4-1BBL, played an important role in the myocardial damage of murine acute viral myocarditis. Methods and results: To investigate the roles for CD27L, CD30L, OX40L and 4-1BBL, which belong to TNF ligand superfamily, in the development of acute myocarditis and dilated cardiomyopathy, we analyzed the expression of these antigens in the myocardial tissues of patients with acute myocarditis and dilated cardiomyopathy. We also examined expression of the receptors for these molecules, CD27, CD30, OX40 and 4-1BB, which belong to TNF receptor superfamily, on the infiltrating cells. Strong expression of CD27L, CD30L and 4-1BBL and weak to moderate expression of OX40L was found in the cardiac myocytes of patients with acute myocarditis. Moderate expression of CD27L, CD30L and 4-1BBL and weak expression of OX40L was found on the cardiac myocytes of patients with dilated cardiomyopathy. Most of the infiltrating cells expressed CD27, CD30 and 4-1BB and a part of the infiltrating cells expressed OX40. Conclusions: Our Findings suggest that expression of TNF ligand superfamily costimulatory molecules on cardiac myocytes may play a role in the cell-mediated myocardial damage in patients with acute myocarditis and dilated cardiomyopathy as in murine viral myocarditis. (C) 2002 Elsevier Science Inc. All rights reserved.

Obesity is a common nutritional problem often associated with diabetes, insulin resistance, and fatty liver (excess fat deposition in liver). Leptin-deficient Lep(ob)/Lep(ob) mice develop obesity and those obesity-related syndromes. Increased lipogenesis in both liver and adipose tissue of these mice has been suggested. We have previously shown that the transcription factor sterol regulatory element-binding protein-1 (SREBP-1) plays a crucial role in the regulation of lipogenesis in vivo. To explore the possible involvement of SREBP-1 in the pathogenesis of obesity and its related syndromes, we generated mice deficient in both leptin and SREBP-1. In doubly mutant Lep(ob/ob) x Srebp-1(-/-) mice, fatty livers were markedly attenuated, but obesity and insulin resistance remained persistent. The mRNA levels of lipogenic enzymes such as fatty acid synthase were proportional to triglyceride accumulation in liver. In contrast, the mRNA abundance of SREBP-1 and lipogenic enzymes in the adipose tissue of Lep(ob)/Lep(ob) mice was profoundly decreased despite sustained fat, which could explain why the SREBP-1 disruption had little effect on obesity. In conclusion, SREBP-1 regulation of lipogenesis is highly involved in the development of fatty livers but does not seem to be a determinant of obesity in Lep(ob)/Lep(ob) mice.

Advanced age is a major risk factor of peripheral artery disease. We examined the effects of the aging-suppressor gene klotho on angiogenesis in response to ischemia by introducing ischemic hindlimb model in mice heterozygously deficient for the klotho gene and in wild type mice. Blood flow recovery as assessed by laser doppler perfusion imaging and angiogenesis as assessed by density of PECAM-1/CD31-positive positive capillaries were markedly impaired in mice heterozygously deficient for the klotho gene (both <0.05). Our findings show that the aging-suppressor gene klotho affects angiogenesis and the possibility that age-related impairment of angiogenesis might be regulated by the klotho gene. Our results present a new possibility of therapeutic angiogenesis for patients of advanced age.

Adrenomedullin (AM) is a potent depressor peptide whose vascular action is suggested to involve nitric oxide (NO) release. To explore the role of endogenous AM in vascular and renal function, we examined the effects of acetylcholine (ACh), AM, and AM receptor antagonists AM(22-52) and CGRP(8-37) on the renal perfusion pressure (RPP) of kidneys isolated from AM transgenic (TG)/heterozygote knockout (KO) mice and wild-type littermates (WT). Furthermore, we evaluated the renal function and histology 24 hours after bilateral renal artery clamp for 45 minutes in TG, KO, and WT mice. Baseline RPP was significantly lower in TG than in KO and WT mice (KO 93.4+/-4.6, WT 85.8+/-4.2, TG 72.4+/-2.4 mm Hg [mean+/-SE], P<0.01). ACh and AM caused a dose-related reduction in RPP, but the degree of vasodilatation was smaller in TG than that in KO and WT (%DeltaRPP 10(-7) mol/L ACh: KO -48.1+/-3.9%, WT -57.5+/-5.6%, TG -22.8+/-4.8%, P<0.01), whereas N(G)-nitro-L-arginine methyl ester (L-NAME) caused greater vasoconstriction in TG (%DeltaRPP 10(-4) mol/L: KO 33.1+/-3.3%, WT 55.5+/-7.2%, TG 152.6+/-21.2%, P<0.01). Both AM antagonists increased RPP in TG to a greater extent compared with KO and WT mice (%DeltaRPP 10(-6) mol/L CGRP(8-37): KO 12.8+/-2.6%, WT 19.4+/-3.6%, TG 41.8+/-8.7%, P<0.01). In mice with ischemic kidneys, serum levels of urea nitrogen and renal damage scores showed smaller values in TG and greater values in KO mice (urea nitrogen: KO 104+/-5>WT 98+/-15>TG 38+/-7 mg/dL, P<0.05 each). Renal NO synthase activity was also greater in TG mice. However, the differences in serum urea nitrogen and renal damage scores among the 3 groups of mice were not observed in mice pretreated with L-NAME. In conclusion, AM antagonists increased renal vascular tone in WT as well as in TG, suggesting that endogenous AM plays a role in the physiological regulation of the vascular tone. AM is likely to protect renal tissues from ischemia/reperfusion injury through its NO releasing activity.

OBJECTIVES This study was designed to investigate the roles of Fas/FasL pathway in myocardial damage in murine acute myocarditis caused by Coxsackie virus B3 (CVB3). BACKGROUND Cardiac myocyte apoptosis rarely occurs in murine acute myocarditis caused by CVB3. Fas/FasL belong to the tumor necrosis factor receptor/ligand superfamily of costimulatory molecules and are known to play a critical role in the induction of apoptosis, as well as in the cytotoxicty mediated by T-cells and natural killer cells. METHODS We first analyzed the expression of Fas on cardiac myoctyes in vivo and in vitro. Second, we examined the development of myocardial damage, in C3H/He mice treated with an anti-FasL monoclonal antibody (mAb), and in C3H/He-lpr/lpr mice and C3H/He-gld/gld mice infected with CVB3. Third, to investigate the effects of anti-FasL mAb treatment on the activation of the infiltrating cells, we examined the expression of interferon (IFN)-gamma and interleukin (IL)-2 as activation markets in the heart of mice by semiquantitative polymerase chain reaction. RESULTS Fas was markedly, induced on cardiac myocytes with acute myocarditis. Myocardial inflammation was decreased in mice treated with anti-Fas L mAb, C3H/He-lpr/lpr mice and C3H/He-gld/gld mice. Anti-FasL mAb-treatment also decreased the expression of IFNgamma, IL-2, inducible nitric oxide synthase and CVB3 genomes in myocardial tissue. CONCLUSIONS Our findings strongly suggested that the Fas/FasL pathway played a critical role in the development of massive myocardial necrosis through activation of infiltrating cells, and raise the possibility of immunotherapy by blocking the Fas/FasL pathway to prevent myocardial damage and improve the prognosis of patients with viral myocarditis. (J Am Coll Cardiol 2002;39:1399 - 403) (C) 2002 by the American College of Cardiology Foundation.

Excessive accumulation of smooth-muscle cells (SMCs) has a key role in the pathogenesis of vascular diseases. It has been assumed that SMCs derived from the outer medial layer migrate, proliferate and synthesize extracellular matrix components on the luminal side of the vessel. Although much effort has been devoted to targeting migration and proliferation of medial SMCs, there is no effective therapy that prevents occlusive vascular remodeling. We show here that in models of post-angioplasty restenosis, graft vasculopathy and hyperlipidemia-induced atherosclerosis, bone-marrow cells give rise to most of the SMCs that contribute to arterial remodeling. Notably, purified hematopoietic stem cells differentiate into SMCs in vitro and in vivo. Our findings indicate that somatic stem cells contribute to pathological remodeling of remote organs, and may provide the basis for the development of new therapeutic strategies for vascular diseases through targeting mobilization, homing, differentiation and proliferation of bone marrow-derived vascular progenitor cells.

Retinoids exert their pleiotropic effects on several pathophysiologic processes, including neointima formation after experimental vascular injury. Plasminogen activator inhibitor-1 (PAI-1) has been proposed to play an inhibitory role in arterial neointima formation after injury. We examined whether retinoids regulate PAI-1 expression in cultured vascular smooth muscle cells (SMCs). Northern blot analysis showed that all-trans retinoic acid (atRA) and 9-cis retinoic acid (9cRA) increased PAI-1 mRNA levels in a dose-dependent manner. These responses were completely inhibited by tyrosine kinase inhibitors. The half-life of PAI-1 was not affected by atRA, suggesting that induction of PAI-1 mRNA was mainly regulated at the transcriptional levels. Stable and transient transfection assays of the human PAI-1 promoter-luciferase constructs indicate that DNA sequence responsive to either ligand-stimulated or overexpressed retinoic acid receptor-alpha expression vector lies downstream of -363 relative to the transcription start site, where no putative retinoic acid response element is found. These results indicate that atRA and 9cRA increase PAI-1 gene transcription through pathways involving tyrosine kinases in SMCs. Because PAI-1 inhibits the production of fibrinolytic protein plasmin that facilitates SMC migration, induction of the PAI-1 gene expression by atRA may at least partly account for the role of atRA as an important inhibitor of neointima formation.

OBJECTIVE: Small or oscillatory wall shear stress accelerates atherosclerosis. MR velocity mapping is feasible for vector analysis of wall shear rate (a spatial gradient of blood flow velocity at the vessel wall) in humans. A relationship between anatomic variations at the aortoiliac bifurcation and characteristics of wall shear rate was evaluated. SUBJECTS AND METHODS: To obtain two components of wall shear rate vectors, an axial component along the vessel axis and a nonaxial component perpendicular to the former at the inner and outer walls of the common iliac arteries just distal to the aortoiliac bifurcation, we performed cine MR velocity mapping with three orthogonal velocity-encoded directions in seven volunteers. RESULTS: The peak axial component at the outer wall (120.6 +/- 37.2 sec(-1)) was smaller than that at the inner wall (196.0 +/- 53.7 sec(-1)) (p < 0.01). Oscillation described by a time integral of the axial component in recessive blood flow direction over integrals in dominant and recessive directions at the outer wall was greater (0.24 +/- 0.11) than that at the inner wall (0.15 +/- 0.08) (p < 0.01). The intersecting angle between the extrapolation of the aortic axis and the direction of the axis of the common iliac artery correlated positively with the peak axial component (r = 0.577, p < 0.05) and inversely with oscillation (r = 0.603, p < 0.05). CONCLUSION: Three-dimensional vector analysis with MR velocity mapping revealed that the outer wall at the aortoiliac bifurcation showed low and oscillatory shear rate, and this inclination was increased when the takeoff angle of the iliac artery was small.

The klotho gene, originally identified by insertional mutagenesis in mice, suppresses the expression of multiple aging-associated phenotypes. This gene is predominantly expressed in the kidney. Recent studies have shown that expression of renal klotho gene is regulated in animal models of metabolic diseases and in humans with chronic renal failure. However, little is known about the mechanisms and the physiological relevance of the regulation of the expression of the klotho gene in the kidney in some diseased conditions. In the present study, we first investigated the role of angiotensin II in the regulation of renal klotho gene expression. Long-term infusion of angiotensin II downregulated renal klotho gene expression at both the mRNA and protein levels. This angiotensin II-induced renal klotho downregulation was an angiotensin type 1 receptor-dependent but pressor-independent event. Adenovirus harboring mouse klotho gene (ad-klotho, 3.3x10(10) plaque forming units) was also intravenously administered immediately before starting angiotensin II infusion in some rats. This resulted in a robust induction of Klotho protein in the liver at day 4, which was still detectable 14 days after the gene transfer. Ad-klotho gene transfer, but not ad-lacZ gene transfer, caused an improvement of creatinine clearance, decrease in urinary protein excretion, and amelioration of histologically demonstrated tubulointerstitial damage induced by angiotensin II administration. Our data suggest that downregulation of the renal klotho gene may have an aggravative role in the development of renal damage induced by angiotensin II, and that induction of the klotho gene may have therapeutic possibilities in treating angiotensin II-induced end organ damage.

Retinoids exert their pleiotropic effects on several pathophysiologic processes, including neointima formation after experimental vascular injury. Plasminogen activator inhibitor-1 (PAI-1) has been proposed to play an inhibitory role in arterial neointima formation after injury. We examined whether retinoids regulate PAI-1 expression in cultured vascular smooth muscle cells (SMCs). Northern blot analysis showed that all-trans retinoic acid (atRA) and 9-cis retinoic acid (9cRA) increased PAI-1 mRNA levels in a dose-dependent manner. These responses were completely inhibited by tyrosine kinase inhibitors. The half-life of PAI-1 was not affected by atRA, suggesting that induction of PAI-1 mRNA was mainly regulated at the transcriptional levels. Stable and transient transfection assays of the human PAI-1 promoter-luciferase constructs indicate that DNA sequence responsive to either ligand-stimulated or overexpressed retinoic acid receptor-alpha expression vector lies downstream of -363 relative to the transcription start site, where no putative retinoic acid response element is found. These results indicate that atRA and 9cRA increase PAI-1 gene transcription through pathways involving tyrosine kinases in SMCs. Because PAI-1 inhibits the production of fibrinolytic protein plasmin that facilitates SMC migration, induction of the PAI-1 gene expression by atRA may at least partly account for the role of atRA as an important inhibitor of neointima formation.