Targeted Disruption of JCAD (Junctional Protein Associated With Coronary Artery Disease)/KIAA1462, a Coronary Artery Disease-Associated Gene Product, Inhibits Angiogenic Processes In Vitro and In Vivo.

OBJECTIVE: Recent genome-wide association studies newly identified the human KIAA1462 gene as a new locus for coronary artery disease. However, the function of the gene product, named JCAD (junctional protein associated with coronary artery disease), is unknown. Because JCAD is expressed at cell-cell junctions in endothelial cells, we hypothesized and tested whether JCAD regulates angiogenic processes in vitro and in vivo. APPROACH AND RESULTS: Cell culture experiments revealed impaired angiogenic ability (proliferation, migration, and cord formation) by the knockdown of JCAD with siRNA (P<0.05 versus control siRNA). We have generated mice lacking JCAD (mKIAA1462-/-) by gene-targeted deletion of JCAD to address in vivo angiogenic function. mKIAA1462-/- mice did not show morphological differences in development of retinal vasculature. Ex vivo aortic ring model demonstrated impaired neovascularization in aorta from mKIAA1462-/- mice than control wild-type mice (P<0.05). Tumor growth was assessed by monitoring tumor volume after the subcutaneous injection of melanoma, LLC (Lewis lung carcinoma), and E0771 cells into the mice. mKIAA1462-/- mice exhibited significantly smaller tumor volume compared with wild-type mice (P<0.001). Histological assessment of the tumor exhibited less smooth muscle actin-positive neovascularization determined by CD31-positive vascular structure in tumor of mKIAA1462-/- mice than wild-type mice, indicating that knockdown of JCAD inhibited the vascular maturation in pathological angiogenic process. CONCLUSIONS: These in vitro and in vivo studies suggest that JCAD has a redundant functional role in physiological angiogenesis but serves a pivotal role in pathological angiogenic process after birth.

Excessive intake of trans fatty acid accelerates atherosclerosis through promoting inflammation and oxidative stress in a mouse model of hyperlipidemia.

BACKGROUND: Epidemiological studies have demonstrated that trans fatty acids (TFAs) are a risk for coronary artery disease. However, the precise mechanism underlying the proatherogenic effect of TFA has not been completely elucidated. To obtain better understanding of the impact of TFA on vascular diseases, this study investigated the effect of TFA on oxidative stress using a mouse model of atherosclerosis. METHODS: Low-density lipoprotein (LDL) receptor knockout mice were fed with diet containing 0.5% cholesterol (control), 0.5% cholesterol+5% elaidic acids (Trans group), and 0.5% cholesterol+5% oleic acids (Cis group) for 8 weeks. Atherosclerotic lesion and oxidative stress in aortic wall were evaluated. In vitro experiments using smooth muscle cells were performed to corroborate in vivo findings. RESULTS: The atherosclerotic lesion area was significantly larger in Trans group than that in control or Cis group. Lipoprotein fractionation was similar among groups, while plasma oxidized LDL level and superoxide production in the vessel wall were markedly increased in Trans group. Elaidic acids were accumulated in a variety of tissues including liver and adipose tissue, which was associated with the high level of inflammatory cytokines in these tissues and plasma. Aortic wall from Trans group showed augmented expression of reactive oxygen species and NAPDH oxidase (p22phox) in smooth muscle cells. In vitro experiments confirmed that elaidic acids upregulated expression of NADPH oxidase and inflammatory cytokines in cultured smooth muscle cells. CONCLUSION: Excessive intake of TFA contributes to the progression of atherosclerosis by evoking inflammation and oxidative stress in mice.

Serum Trans-Fatty Acid Concentration Is Elevated in Young Patients With Coronary Artery Disease in Japan.

BACKGROUND: Adverse effects of dietary intake of trans-fatty acids (TFA) on the incidence of coronary artery disease (CAD) are well recognized in Western countries. The risk of TFA, however, has not been well clarified in Japan. We investigated the association of serum TFA concentration with serum lipid profile, coronary risk factors, and prevalence of CAD. METHODS AND RESULTS: A total of 902 patients, who were hospitalized at Kobe University Hospital from July 2008 to March 2012 and gave written informed consent, were enrolled in this study. Among them, 463 patients had CAD, and 318 patients had metabolic syndrome (MetS). Serum TFA, elaidic acid (trans-9-C18:1) and linolelaidic acid (trans-9, 12-C18:2), were measured on gas chromatography/mass spectrometry. Serum TFA level had a positive correlation with body mass index, waist circumference, low-density lipoprotein cholesterol, triglycerides, and apolipoprotein B48, and an inverse correlation with age and high-density lipoprotein cholesterol. Fasting serum TFA, by age quartile in the young generation with CAD and/or MetS, was higher than that in patients without CAD and/or MetS. On multivariate logistic regression, TFA was identified as a CAD risk after adjustment for classical risk factors. CONCLUSIONS: Serum TFA concentration was elevated in young patients with CAD and/or MetS. Diet-derived TFA may cause a serious health problem, particularly in the young generation in Japan.

Trans-fatty acid promotes thrombus formation in mice by aggravating antithrombogenic endothelial functions via Toll-like receptors.

SCOPE: Since excessive intake of trans-fatty acid (TFA) increases the risk of myocardial infarction, we investigated the effects of TFA on thrombus formation using animal and cell culture experiments. METHODS AND RESULTS: C57BL/6 mice were fed a diet containing TFA or cis-fatty acid (5% each of total calories) or a chow diet for 4 weeks, and thrombus formation was induced in the carotid artery by He-Ne laser irradiation. The high-TFA diet significantly promoted thrombus formation in the carotid artery compared to the chow or cis-fatty acid diet. TFA activated the inflammatory signaling pathway in cultured endothelial cells and in mice; aortic gene expression levels of antithrombogenic molecules, including thrombomodulin and tissue factor pathway inhibitor, were decreased, and the expression levels of prothrombogenic molecules were increased in TFA-treated mice. TFA markedly upregulated the prothrombogenic molecules and downregulated the antithrombogenic molecules in endothelial cells. In addition, TFA induced phosphorylation of c-Jun N-terminal kinase, extracellular signal-regulated kinase, and nuclear factor-κB. The TFA-activated signal pathways and prothrombogenic phenotypic changes of endothelial cells were inhibited by genetic or pharmacological inactivation of Toll-like receptors 2 and 4. CONCLUSION: TFA aggravates the antithrombogenic phenotypes of vascular endothelial cells via Toll-like receptors and promotes thrombus formation in mice.

Administration of high dose eicosapentaenoic acid enhances anti-inflammatory properties of high-density lipoprotein in Japanese patients with dyslipidemia.

OBJECTIVE: It has been reported that high-density lipoprotein (HDL) loses anti-inflammatory function and promotes atherosclerosis under pathological conditions. However, no pharmacological therapy to improve HDL function is currently available. We aimed to evaluate the effect of oral administration of eicosapentaenoic acid (EPA) on HDL function. METHODS: Japanese patients with dyslipidemia were treated with EPA (1800 mg/day, 4 weeks), and anti-inflammatory functions of HDL were assessed utilizing in vitro cell-based assays. RESULTS: The EPA treatment did not change serum cholesterol and triglyceride levels, but it significantly increased EPA concentrations in the serum and HDL fraction. The EPA/arachidonic acid ratio in the HDL was in proportion to that in the serum, suggesting that the orally administered EPA was efficiently incorporated into the HDL particles. The HDL after EPA treatment showed significantly increased activity of anti-oxidative enzyme, paraoxonase-1. In addition, the EPA-rich HDL significantly improved endothelial cell migration, and markedly inhibited cytokine-induced expression of vascular cell adhesion molecule-1, in human umbilical vein endothelial cells, compared to HDL before the EPA treatment. Moreover, the EPA-rich HDL augmented cholesterol efflux capacity from macrophages. CONCLUSION: Oral administration of EPA regenerated anti-oxidative and anti-inflammatory functions of HDL, and promoted cholesterol efflux from macrophages. Therefore, EPA may transform "dysfunctional HDL" to "functional", in patients with coronary risk factors.

Pitavastatin increases HDL particles functionally preserved with cholesterol efflux capacity and antioxidative actions in dyslipidemic patients.

AIM: Although statins increase the plasma concentration of high-density lipoprotein cholesterol (HDL-C), it has not been elucidated whether the increased HDL particles possess normal antiatherosclerotic properties. Pitavastatin functions to increase the plasma HDL-C level and decrease the lowdensity lipoprotein cholesterol (LDL-C) level. In the present study, we sought to examine the qualitative changes in HDL during pitavastatin treatment. METHODS: A total of 30 patients with dyslipidemia were treated with 2 mg of pitavastatin for four weeks. The cholesterol efflux capacity and activities of the antioxidative enzymes paraoxonase-1 (PON-1) and platelet-activating factor acetylhydrolase (PAF-AH) were evaluated using polyethethylene glycol-treated HDL fractions before and after pitavastatin treatment. RESULTS: Pitavastatin treatment decreased the serum LDL-C level by 39% and increased the serum HDL-C level by 9% (p＜0.05). In addition, pitavastatin increased the phospholipid content of HDL by 7.8% (p＜0.05). The pitavastatin-induced increase in the HDL-C level coincided with an increase in the cholesterol efflux capacity of the isolated HDL fraction of 8.6% (p＜0.05). The post-pitavastatin treatment activity of HDL-associated PON-1 (paraoxonase and arylesterase) was increased by 9% (p＜0.05) and 11% (p＜0.05), respectively, while the HDL-associated PAF-AH activity was not affected by pitavastatin. CONCLUSIONS: In addition to its LDL-C-lowering effects, pitavastatin elevates the HDL-C level and enhances the cholesterol efflux capacity and antioxidative properties of HDL. Pitavastatin therefore increases the amount of functional HDL without attenuating HDL quality.

Fasting serum concentration of apolipoprotein B48 represents residual risks in patients with new-onset and chronic coronary artery disease.

BACKGROUND: To identify new therapeutic targets for coronary artery disease (CAD), we investigated whether fasting serum concentration of apolipoprotein (apo) B48 could be a marker for CAD. METHODS: Patients with CAD were divided into those with new-onset CAD [i.e., those receiving percutaneous coronary intervention (PCI) for the first time] and those with chronic CAD (i.e., those receiving follow-up coronary angiography). Fasting serum biochemical analyses were performed on admission and 6 months after the PCI. RESULTS: On admission, serum LDL-C concentrations in patients with chronic CAD (n=138), presumably receiving statin treatment, were lower than in patients with new-onset CAD (n=50, p<0.02) or without CAD (n=71, p<0.001). Nevertheless, apoB48 was higher in CAD patients than in those without CAD (p<0.001). After adjusting for classic cardiovascular risk factors, multivariate logistic regression analyses showed apoB48 to be an independent predictor of coronary risk in new-onset or chronic CAD, irrespective of the LDL-C levels. Moreover, apoB48 was markedly increased during the follow-up period in CAD patients having new lesion progression after the prior PCI. CONCLUSION: Fasting serum apoB48 concentration could be a marker of new onset as well as chronic CAD, and predict new lesion progression in secondary prevention.

Isolated ACTH deficiency presenting with severe myocardial dysfunction.

We present a case of isolated adrenocorticotropic hormone (ACTH) deficiency complicated by acute adrenal crisis and severe myocardial dysfunction. A 54-year-old woman developed consciousness disturbance, hypoglycemia, hyponatremia, and rhabdomyolysis. Initial echocardiographic examinations on the sixth hospital day revealed marked right-sided atrial and ventricular dilatation and severe tricuspid regurgitation. A computed tomography scan for pulmonary embolism was negative. On the 14th hospital day, she became dyspneic and hypotensive. Repeated echocardiographic examinations demonstrated diffuse and severe hypokinesis of the left ventricle. The previous right-sided chamber dilatation became less apparent. Congestive heart failure and severe hypotension were refractory to catecholamines, while she was eventually diagnosed as having acute adrenal crisis due to isolated ACTH deficiency. Hydrocortisone replacement therapy was started, and echocardiographic examinations revealed that the left ventricular dysfunction completely returned to normal in the following eight days. Severe myocardial dysfunction is an uncommon but serious complication of acute adrenal insufficiency. The present case was unique in that diffuse left ventricular dysfunction was preceded by right ventricular dysfunction.