CD40L Deficiency Attenuates Diet-Induced Adipose Tissue Inflammation by Impairing Immune Cell Accumulation and Production of Pathogenic IgG-Antibodies

BACKGROUND: Adipose tissue inflammation fuels the metabolic syndrome. We recently reported that CD40L--an established marker and mediator of cardiovascular disease--induces inflammatory cytokine production in adipose cells in vitro. Here, we tested the hypothesis that CD40L deficiency modulates adipose tissue inflammation in vivo. METHODOLOGY/PRINCIPAL FINDINGS: WT or CD40L(-/-) mice consumed a high fat diet (HFD) for 20 weeks. Inflammatory cell recruitment was impaired in mice lacking CD40L as shown by a decrease of adipose tissue macrophages, B-cells, and an increase in protective T-regulatory cells. Mechanistically, CD40L-deficient mice expressed significantly lower levels of the pro-inflammatory chemokine MCP-1 both, locally in adipose tissue and systemically in plasma. Moreover, levels of pro-inflammatory IgG-antibodies against oxidized lipids were reduced in CD40L(-/-) mice. Also, circulating low-density lipoproteins and insulin levels were lower in CD40L(-/-) mice. However, CD40L(-/-) mice consuming HFD were not protected from the onset of diet-induced obesity (DIO), insulin resistance, and hepatic steatosis, suggesting that CD40L selectively limits the inflammatory features of diet-induced obesity rather than its metabolic phenotype. Interestingly, CD40L(-/-) mice consuming a low fat diet (LFD) showed both, a favorable inflammatory and metabolic phenotype characterized by diminished weight gain, improved insulin tolerance, and attenuated plasma adipokine levels. CONCLUSION: We present the novel finding that CD40L deficiency limits adipose tissue inflammation in vivo. These findings identify CD40L as a potential mediator at the interface of cardiovascular and metabolic disease

Tumor Necrosis Factor Receptor Associated Factor 6 Is Not Required for Atherogenesis in Mice and Does Not Associate with Atherosclerosis in Humans

BACKGROUND: Tumor necrosis factor receptor-associated factors (TRAFs) are important signaling molecules for a variety of pro-atherogenic cytokines including CD40L, TNF alpha, and IL1beta. Several lines of evidence identified TRAF6 as a pro-inflammatory signaling molecule in vitro and we previously demonstrated overexpression of TRAF6 in human and Murine atherosclerotic plaques. This study investigated the role of TRAF6-deficiency in mice developing atherosclerosis, a chronic inflammatory disease. METHODOLOGY/PRINCIPAL FINDINGS: Lethally irradiated low density lipoprotein receptor-deficient mice (TRAF6(+/+)/LDLR(-/-)) were reconstituted with TRAF6-deficient fetal liver cells (FLC) and consumed high cholesterol diet for 18 weeks to assess the relevance of TRAF6 in hematopoietic cells for atherogenesis. Additionally, TRAF6(+/-)/LDLR(-/-) mice received TRAF6-deficient FLC to gain insight into the role of TRAF6 deficiency in resident cells. Surprisingly, atherosclerotic lesion size did not differ between the three groups in both aortic roots and abdominal aortas. Similarly, no significant differences in plaque composition could be observed as assessed by immunohistochemistry for macrophages, lipids, smooth muscle cells, T-cells, and collagen. In accord, in a small clinical study TRAF6/GAPDH total blood RNA ratios did not differ between groups of patients with stable coronary heart disease (0.034+/-0.0021, N = 178), acute coronary heart disease (0.029+/-0.0027, N = 70), and those without coronary heart disease (0.032+/-0.0016, N = 77) as assessed by angiography. CONCLUSION: Our study demonstrates that TRAF6 is not required for atherogenesis in mice and does not associate with clinical disease in humans. These data suggest that pro- and anti-inflammatory features of TRAF6 signaling outweigh each other in the context of atherosclerosis

Soluble CD40 ligand and prolactin levels in migraine patients during interictal period

The relationship of migraine with cardiovascular diseases has been clarified by many studies, and currently, migraine is suggested to be a systematic vasculopathy. Inflammation, thrombosis and impaired vascular reactivity are the underlying pathophysiological mechanisms of the vasculopathy. In the present study, we aimed to investigate the relationship between prolactin levels and subclinical atherosclerosis risk factors such as soluble CD40 ligand (sCD40L) and high-sensitivity CRP (hsCRP) in migraine patients during interictal period. Fifty female migraine patients and age-matched 25 female control cases were enrolled in the study. Migraine diagnosis was settled according to the ICHD-II diagnostic criteria. A questionnaire was completed about the existence of vascular risk factors. Serum samples were used to measure sCD40L, hsCRP and prolactin levels. No difference was found between the prolactin levels of the migraine patients and the controls. The sCD40L levels were significantly higher in migraine patients (p < 0.001). High-sensitivity CRP levels showed no difference between the groups. There was no correlation between prolactin, sCD40L, and hs-CRP levels in migraine patients. We consider that the migraine patients are prone to subclinical atherosclerosis, but this tendency is independent of prolactin levels

Peroxisome Proliferator-Activated Receptor-Gamma Agonists Suppress Tissue Factor Overexpression in Rat Balloon Injury Model with Paclitaxel Infusion

The role and underlying mechanisms of rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPAR-γ) agonist, on myocardial infarction are poorly understood. We investigated the effects of this PPAR-γ agonist on the expression of tissue factor (TF), a primary molecule for thrombosis, and elucidated its underlying mechanisms. The PPAR-γ agonist inhibited TF expression in response to TNF-α in human umbilical vein endothelial cells, human monocytic leukemia cell line, and human umbilical arterial smooth muscle cells. The overexpression of TF was mediated by increased phosphorylation of mitogen-activated protein kinase (MAPK), which was blocked by the PPAR-γ agonist. The effective MAPK differed depending on each cell type. Luciferase and ChIP assays showed that transcription factor, activator protein-1 (AP-1), was a pivotal target of the PPAR-γ agonist to lower TF transcription. Intriguingly, two main drugs for drug-eluting stent, paclitaxel or rapamycin, significantly exaggerated thrombin-induced TF expression, which was also effectively blocked by the PPAR-γ agonist in all cell types. This PPAR-γ agonist did not impair TF pathway inhibitor (TFPI) in three cell types. In rat balloon injury model (Sprague-Dawley rats, n = 10/group) with continuous paclitaxel infusion, the PPAR-γ agonist attenuated TF expression by 70±5% (n = 4; P<0.0001) in injured vasculature. Taken together, rosiglitazone reduced TF expression in three critical cell types involved in vascular thrombus formation via MAPK and AP-1 inhibitions. Also, this PPAR-γ agonist reversed the paclitaxel-induced aggravation of TF expression, which suggests a possibility that the benefits might outweigh its risks in a group of patients with paclitaxel-eluting stent implanted

Cannabinoid Receptor 2 Signaling Does Not Modulate Atherogenesis in Mice

BACKGROUND:Strong evidence supports a protective role of the cannabinoid receptor 2 (CB(2)) in inflammation and atherosclerosis. However, direct proof of its involvement in lesion formation is lacking. Therefore, the present study aimed to characterize the role of the CB(2) receptor in Murine atherogenesis. METHODS AND FINDINGS:Low density lipoprotein receptor-deficient (LDLR(-/-)) mice subjected to intraperitoneal injections of the selective CB(2) receptor agonist JWH-133 or vehicle three times per week consumed high cholesterol diet (HCD) for 16 weeks. Surprisingly, intimal lesion size did not differ between both groups in sections of the aortic roots and arches, suggesting that CB(2) activation does not modulate atherogenesis in vivo. Plaque content of lipids, macrophages, smooth muscle cells, T cells, and collagen were also similar between both groups. Moreover, CB(2) (-/-)/LDLR(-/-) mice developed lesions of similar size containing more macrophages and lipids but similar amounts of smooth muscle cells and collagen fibers compared with CB(2) (+/+)/LDLR(-/-) controls. While JWH-133 treatment reduced intraperitoneal macrophage accumulation in thioglycollate-elicited peritonitis, neither genetic deficiency nor pharmacologic activation of the CB(2) receptor altered inflammatory cytokine expression in vivo or inflammatory cell adhesion in the flow chamber in vitro. CONCLUSION:Our study demonstrates that both activation and deletion of the CB(2) receptor do not relevantly modulate atherogenesis in mice. Our data do not challenge the multiple reports involving CB(2) in other inflammatory processes. However, in the context of atherosclerosis, CB(2) does not appear to be a suitable therapeutic target for reduction of the atherosclerotic plaque

Effects of Anacetrapib in Patients with Atherosclerotic Vascular Disease

BACKGROUND: Patients with atherosclerotic vascular disease remain at high risk for cardiovascular events despite effective statin-based treatment of low-density lipoprotein (LDL) cholesterol levels. The inhibition of cholesteryl ester transfer protein (CETP) by anacetrapib reduces LDL cholesterol levels and increases high-density lipoprotein (HDL) cholesterol levels. However, trials of other CETP inhibitors have shown neutral or adverse effects on cardiovascular outcomes. METHODS: We conducted a randomized, double-blind, placebo-controlled trial involving 30,449 adults with atherosclerotic vascular disease who were receiving intensive atorvastatin therapy and who had a mean LDL cholesterol level of 61 mg per deciliter (1.58 mmol per liter), a mean non-HDL cholesterol level of 92 mg per deciliter (2.38 mmol per liter), and a mean HDL cholesterol level of 40 mg per deciliter (1.03 mmol per liter). The patients were assigned to receive either 100 mg of anacetrapib once daily (15,225 patients) or matching placebo (15,224 patients). The primary outcome was the first major coronary event, a composite of coronary death, myocardial infarction, or coronary revascularization. RESULTS: During the median follow-up period of 4.1 years, the primary outcome occurred in significantly fewer patients in the anacetrapib group than in the placebo group (1640 of 15,225 patients [10.8%] vs. 1803 of 15,224 patients [11.8%]; rate ratio, 0.91; 95% confidence interval, 0.85 to 0.97; P=0.004). The relative difference in risk was similar across multiple prespecified subgroups. At the trial midpoint, the mean level of HDL cholesterol was higher by 43 mg per deciliter (1.12 mmol per liter) in the anacetrapib group than in the placebo group (a relative difference of 104%), and the mean level of non-HDL cholesterol was lower by 17 mg per deciliter (0.44 mmol per liter), a relative difference of -18%. There were no significant between-group differences in the risk of death, cancer, or other serious adverse events. CONCLUSIONS: Among patients with atherosclerotic vascular disease who were receiving intensive statin therapy, the use of anacetrapib resulted in a lower incidence of major coronary events than the use of placebo. (Funded by Merck and others; Current Controlled Trials number, ISRCTN48678192 ; ClinicalTrials.gov number, NCT01252953 ; and EudraCT number, 2010-023467-18 .)

Unchanged protein levels of SERCA II and phospholamban but reduced Ca2+uptake and Ca2+-ATPase activity of cardiac sarcoplasmic reticulum from dilated cardiomyopathy patients compared with patients with nonfailing hearts

BACKGROUND: The aim of the present study was to investigate whether Ca2+ uptake into the sarcoplasmic reticulum (SR) is altered in failing human myocardium resulting from dilated cardiomyopathy. METHODS AND RESULTS: Ca(2+)-ATPase (SERCA II) activity and Ca(2+)-dependent 45Ca2+ uptake (oxalate supported, steady state) in isolated vesicles from the SR (VSR) and in crude membrane preparations (CSR) (free Ca2+, 0.01 to 100 mumol/L) from nonfailing (donor hearts, n = 13) and terminally failing (heart transplants, dilated cardiomyopathy, n = 17) human myocardium were studied. In the same hearts, protein levels (Western blot analysis) and mRNA levels (Northern blot analysis) of SERCA II and phospholamban were measured. Increasing concentrations of Ca2+ were followed by an increased Ca(2+)-ATPase activity and Ca2+ uptake. Ca2+ uptake activity and Ca(2+)-ATPase activity in CSR preparations from failing myocardium were significantly reduced compared with nonfailing hearts (Ca(2+)-ATPase, 163 +/- 8 and 125 +/- 7 nmol ATP/mg protein per minute for nonfailing tissue and failing tissue in New York Heart Association [NYHA] class IV, respectively; Ca2+ uptake, 7.1 +/- 0.8 and 3.5 +/- 0.3 nmol/mg protein per minute in CSR from nonfailing and NYHA class IV hearts, respectively P < .05). In contrast, no significant difference was measured in VSR. In the same preparations (CSR and VSR), both SERCA II and phospholamban levels (Western blot technique with monoclonal antibodies) were unchanged in failing compared with nonfailing tissue. mRNA expression relative to GAPDH mRNA for SERCA IIa and for phospholamban was significantly reduced in failing human myocardium (P < .05). CONCLUSIONS: These findings provide evidence that in failing human myocardium caused by dilated cardiomyopathy, protein levels of SERCA II and phospholamban are unchanged even though mRNA levels for SERCA II and phospholamban and the SERCA II function are reduced compared with nonfailing myocardium