The in vitro effects of resistin on the innate immune signaling pathway in isolated human subcutaneous adipocytes

Context: Obesity-associated inflammation is a contributory factor in the pathogenesis of type 2 diabetes mellitus (T2DM); the mechanisms underlying the progression to T2DM are unclear. The adipokine resistin has demonstrated pro-inflammatory properties in relation to obesity and T2DM. Objective: To characterize resistin expression in human obesity and address the role of resistin in the innate immune pathway. Furthermore, examine the influence of lipopolysaccharide, recombinant human resistin (rhResistin), insulin and rosiglitazone in human adipocytes. Finally, analyze the effect of rhResistin on the expression of components of the NF-κB pathway and insulin signaling cascade. Methods: Abdominal subcutaneous adipose tissue was obtained from patients undergoing elective liposuction surgery (n = 35, aged: 36-49 yr; BMI: 26.5 ± 5.9 kg/m2). Isolated adipocytes were cultured with rhResistin (10-50 ng/ml). The level of cytokine secretion from isolated adipocytes was examined by ELISA. The effect of rhResistin on protein expression of components of the innate immune pathway was examined by Western blot. Results: In-vitro studies demonstrated that antigenic stimuli increase resistin secretion (P < 0.001) from isolated adipocytes. Pro-inflammatory cytokine levels were increased in response to rhResistin (P < 0.001); this was attenuated by rosiglitazone (P < 0.01). When examining components of the innate immune pathway, rhResistin stimulated Toll-like receptor-2 protein expression. Similarly, mediators of the insulin signaling pathway, phosphospecific JNK1 and JNK2, were upregulated in response to rhResistin. Conclusion: Resistin may participate in more than one mechanism to influence pro-inflammatory cytokine release from human adipocytes; potentially via the integration of NF-κB and JNK signaling pathways

TIMP3 Is Reduced in Atherosclerotic Plaques From Subjects With Type 2 Diabetes and Increased by SirT1

Atherosclerosis is accelerated in subjects with type 2 diabetes by unknown mechanisms. We identified tissue inhibitor of metalloproteinase 3 (TIMP3), the endogenous inhibitor of A disintegrin and metalloprotease domain 17 (ADAM17) and other matrix metalloproteinases (MMPs), as a gene modifier for insulin resistance and vascular inflammation in mice. We tested its association with atherosclerosis in subjects with type 2 diabetes and identified Sirtuin 1 (SirT1) as a major regulator of TIMP3 expression

Macrophage-derived human resistin is induced in multiple helminth infections and promotes inflammatory monocytes and increased parasite burden.

Parasitic helminth infections can be associated with lifelong morbidity such as immune-mediated organ failure. A better understanding of the host immune response to helminths could provide new avenues to promote parasite clearance and/or alleviate infection-associated morbidity. Murine resistin-like molecules (RELM) exhibit pleiotropic functions following helminth infection including modulating the host immune response; however, the relevance of human RELM proteins in helminth infection is unknown. To examine the function of human resistin (hResistin), we utilized transgenic mice expressing the human resistin gene (hRetnTg+). Following infection with the helminth Nippostrongylus brasiliensis (Nb), hResistin expression was significantly upregulated in infected tissue. Compared to control hRetnTg- mice, hRetnTg+ mice suffered from exacerbated Nb-induced inflammation characterized by weight loss and increased infiltration of inflammatory monocytes in the lung, along with elevated Nb egg burdens and delayed parasite expulsion. Genome-wide transcriptional profiling of the infected tissue revealed that hResistin promoted expression of proinflammatory cytokines and genes downstream of toll-like receptor signaling. Moreover, hResistin preferentially bound lung monocytes, and exogenous treatment of mice with recombinant hResistin promoted monocyte recruitment and proinflammatory cytokine expression. In human studies, increased serum resistin was associated with higher parasite load in individuals infected with soil-transmitted helminths or filarial nematode Wuchereria bancrofti, and was positively correlated with proinflammatory cytokines. Together, these studies identify human resistin as a detrimental factor induced by multiple helminth infections, where it promotes proinflammatory cytokines and impedes parasite clearance. Targeting the resistin/proinflammatory cytokine immune axis may provide new diagnostic or treatment strategies for helminth infection and associated immune-mediated pathology

Green tea halts progression of cardiac transthyretin amyloidosis: an observational report

BACKGROUND: Treatment options in patients with amyloidotic transthyretin (ATTR) cardiomyopathy are limited. Epigallocatechin-3-gallate (EGCG), the most abundant catechin in green tea (GT), inhibits fibril formation from several amyloidogenic proteins in vitro. Thus, it might also halt progression of TTR amyloidosis. This is a single-center observational report on the effects of GT consumption in patients with ATTR cardiomopathy. METHODS: 19 patients with ATTR cardiomyopathy were evaluated by standard blood tests, echocardiography, and cardiac MRI (n = 9) before and after consumption of GT and/or green tea extracts (GTE) for 12 months. RESULTS: Five patients were not followed up for reasons of death (n = 2), discontinuation of GT/GTE consumption (n = 2), and heart transplantation (n = 1). After 12 months no increase of left ventricular (LV) wall thickness and LV myocardial mass was observed by echocardiography. In the subgroup of patients evaluated by cardiac MRI a mean decrease of LV myocardial mass (-12.5 %) was detected in all patients. This was accompanied by an increase of mean mitral annular systolic velocity of 9 % in all 14 patients. Total cholesterol (191.9 ± 8.9 vs. 172.7 ± 9.4 mg/dL; p < 0.01) and LDL cholesterol (105.8 ± 7.6 vs. 89.5 ± 8.0 mg/dL; p < 0.01) decreased significantly during the observational period. No serious adverse effects were reported by any of the participants. CONCLUSIONS: Our observation suggests an inhibitory effect of GT and/or GTE on the progression of cardiac amyloidosis. We propose a randomized placebo-controlled investigation to confirm our observation

Development of the iCook 4-H Curriculum for Youth and Adults: Cooking, Eating, and Playing Together for Childhood Obesity Prevention

The objective was to describe the development process of a curriculum (iCook 4-H) targeted to low-income, rural, and/or diverse youths and their adult primary meal preparer to promote cooking, eating, and playing together. Lessons learned highlighted the importance of grounding the curriculum in Social Cognitive Theory and applying the experiential 4-H learning model using a multiphased, community-based participatory approach with cyclical development and evaluation, and key modifications made for dissemination and distribution. Findings across 4 testing phases over 6 years and 5 states demonstrated the time-intensive, cyclical process that required flexibility with fidelity to form a hands-on, interactive curriculum

Common carotid intima media thickness and ankle-brachial pressure index correlate with local but not global atheroma burden:a cross sectional study using whole body magnetic resonance angiography

Common carotid intima media thickness (CIMT) and ankle brachial pressure index (ABPI) are used as surrogate marker of atherosclerosis, and have been shown to correlate with arterial stiffness, however their correlation with global atherosclerotic burden has not been previously assessed. We compare CIMT and ABPI with atheroma burden as measured by whole body magnetic resonance angiography (WB-MRA).50 patients with symptomatic peripheral arterial disease were recruited. CIMT was measured using ultrasound while rest and exercise ABPI were performed. WB-MRA was performed in a 1.5T MRI scanner using 4 volume acquisitions with a divided dose of intravenous gadolinium gadoterate meglumine (Dotarem, Guerbet, FR). The WB-MRA data was divided into 31 anatomical arterial segments with each scored according to degree of luminal narrowing: 0 = normal, 1 = <50%, 2 = 50-70%, 3 = 70-99%, 4 = vessel occlusion. The segment scores were summed and from this a standardized atheroma score was calculated.The atherosclerotic burden was high with a standardised atheroma score of 39.5±11. Common CIMT showed a positive correlation with the whole body atheroma score (β 0.32, p = 0.045), however this was due to its strong correlation with the neck and thoracic segments (β 0.42 p = 0.01) with no correlation with the rest of the body. ABPI correlated with the whole body atheroma score (β -0.39, p = 0.012), which was due to a strong correlation with the ilio-femoral vessels with no correlation with the thoracic or neck vessels. On multiple linear regression, no correlation between CIMT and global atheroma burden was present (β 0.13 p = 0.45), while the correlation between ABPI and atheroma burden persisted (β -0.45 p = 0.005).ABPI but not CIMT correlates with global atheroma burden as measured by whole body contrast enhanced magnetic resonance angiography in a population with symptomatic peripheral arterial disease. However this is primarily due to a strong correlation with ilio-femoral atheroma burden

PPAR? Downregulation by TGF in Fibroblast and Impaired Expression and Function in Systemic Sclerosis: A Novel Mechanism for Progressive Fibrogenesis

The nuclear orphan receptor peroxisome proliferator-activated receptor-gamma (PPAR-γ) is expressed in multiple cell types in addition to adipocytes. Upon its activation by natural ligands such as fatty acids and eicosanoids, or by synthetic agonists such as rosiglitazone, PPAR-γ regulates adipogenesis, glucose uptake and inflammatory responses. Recent studies establish a novel role for PPAR-γ signaling as an endogenous mechanism for regulating transforming growth factor-ß (TGF-ß)- dependent fibrogenesis. Here, we sought to characterize PPAR-γ function in the prototypic fibrosing disorder systemic sclerosis (SSc), and delineate the factors governing PPAR-γ expression. We report that PPAR-γ levels were markedly diminished in skin and lung biopsies from patients with SSc, and in fibroblasts explanted from the lesional skin. In normal fibroblasts, treatment with TGF-ß resulted in a time- and dose-dependent down-regulation of PPAR-γ expression. Inhibition occurred at the transcriptional level and was mediated via canonical Smad signal transduction. Genome-wide expression profiling of SSc skin biopsies revealed a marked attenuation of PPAR-γ levels and transcriptional activity in a subset of patients with diffuse cutaneous SSc, which was correlated with the presence of a ''TGF-ß responsive gene signature'' in these biopsies. Together, these results demonstrate that the expression and function of PPAR-γ are impaired in SSc, and reveal the existence of a reciprocal inhibitory cross-talk between TGF-ß activation and PPAR-γ signaling in the context of fibrogenesis. In light of the potent anti-fibrotic effects attributed to PPAR-γ, these observations lead us to propose that excessive TGF-ß activity in SSc accounts for impaired PPAR-γ function, which in turn contributes to unchecked fibroblast activation and progressive fibrosis. © 2010 Wei et al

PPARγ population shift produces disease-related changes in molecular networks associated with metabolic syndrome

Peroxisome proliferator-activated receptor gamma (PPARγ) is a key regulator of adipocyte differentiation and has an important role in metabolic syndrome. Phosphorylation of the receptor's ligand-binding domain at serine 273 has been shown to change the expression of a large number of genes implicated in obesity. The difference in gene expression seen when comparing wild-type phosphorylated with mutant non-phosphorylated PPARγ may have important consequences for the cellular molecular network, the state of which can be shifted from the healthy to a stable diseased state. We found that a group of differentially expressed genes are involved in bi-stable switches and form a core network, the state of which changes with disease progression. These findings support the idea that bi-stable switches may be a mechanism for locking the core gene network into a diseased state and for efficiently propagating perturbations to more distant regions of the network. A structural analysis of the PPARγ–RXRα dimer complex supports the hypothesis of a major structural change between the two states, and this may represent an important mechanism leading to the differential expression observed in the core network

Mechanical effects of left ventricular midwall fibrosis in non-ischemic cardiomyopathy

Background: Left ventricular (LV) mid-wall fibrosis (MWF), which occurs in about a quarter of patients with non-ischemic cardiomyopathy (NICM), is associated with high risk of pump failure. The mid LV wall is the site of circumferential myocardial fibers. We sought to determine the effect of MWF on LV myocardial mechanics. Methods: Patients with NICM (n = 116; age: 62.8 ± 13.2 years; 67 % male) underwent late gadolinium enhancement cardiovascular magnetic resonance (CMR) and were categorized according to the presence (+) or absence (-) of MWF. Feature tracking (FT) CMR was used to assess myocardial deformation. Results: Despite a similar LVEF (24.3 vs 27.5 %, p = 0.20), patients with MWF (32 [24 %]) had lower global circumferential strain (εcc: -6.6 % vs -9.4 %, P = 0.004), but similar longitudinal (εll: -7.6 % vs. -9.4 %, p = 0.053) and radial (εrr: 14.6 % vs. 17.8 % p = 0.18) strain. Compared with - MWF, + MWF was associated with reduced LV systolic, circumferential strain rate (-0.38 ± 0.1 vs -0.56 ± 0.3 s-1, p = 0.005) and peak LV twist (4.65 vs. 6.31°, p = 0.004), as well as rigid LV body rotation (64 % vs 28 %, P cc: 0.34 vs. 0.46 s-1; DSRll: 0.38 vs. 0.50s-1; DSRrr: -0.55 vs. -0.75 s-1; all

Adverse events in families with hypertrophic or dilated cardiomyopathy and mutations in the MYBPC3 gene

<p>Abstract</p> <p>Background</p> <p>Mutations in <it>MYBPC3 </it>encoding myosin binding protein C belong to the most frequent causes of hypertrophic cardiomyopathy (HCM) and may also lead to dilated cardiomyopathy (DCM). <it>MYBPC3 </it>mutations initially were considered to cause a benign form of HCM. The aim of this study was to examine the clinical outcome of patients and their relatives with 18 different <it>MYBPC3 </it>mutations.</p> <p>Methods</p> <p>87 patients with HCM and 71 patients with DCM were screened for <it>MYBPC3 </it>mutations by denaturing gradient gel electrophoresis and sequencing. Close relatives of mutation carriers were genotyped for the respective mutation. Relatives with mutation were then evaluated by echocardiography and magnetic resonance imaging. A detailed family history regarding adverse clinical events was recorded.</p> <p>Results</p> <p>In 16 HCM (18.4%) and two DCM (2.8%) index patients a mutation was detected. Seven mutations were novel. Mutation carriers exhibited no additional mutations in genes <it>MYH7</it>, <it>TNNT2</it>, <it>TNNI3</it>, <it>ACTC </it>and <it>TPM1</it>. Including relatives of twelve families, a total number of 42 mutation carriers was identified of which eleven (26.2%) had at least one adverse event. Considering the twelve families and six single patients with mutations, 45 individuals with cardiomyopathy and nine with borderline phenotype were identified. Among the 45 patients, 23 (51.1%) suffered from an adverse event. In eleven patients of seven families an unexplained sudden death was reported at the age between 13 and 67 years. Stroke or a transient ischemic attack occurred in six patients of five families. At least one adverse event occurred in eleven of twelve families.</p> <p>Conclusion</p> <p><it>MYBPC3 </it>mutations can be associated with cardiac events such as progressive heart failure, stroke and sudden death even at younger age. Therefore, patients with <it>MYBPC3 </it>mutations require thorough clinical risk assessment.</p