PCSK9 Expression in Epicardial Adipose Tissue : Molecular Association with Local Tissue Inflammation

Epicardial adipose tissue (EAT) has the unique property to release mediators that nourish the heart in healthy conditions, an effect that becomes detrimental when volume expands and proinflammatory cytokines start to be produced. Proprotein convertase subtilisin/kexin type 9 (PCSK9), a proinflammatory mediator involved in atherosclerosis, is also produced by visceral fat. Due to the correlation of inflammation with PCSK9 and EAT enlargement, we evaluated whether PCSK9 was expressed in EAT and associated with EAT inflammation and volume. EAT samples were isolated during surgery. EAT thickness was measured by echocardiography. A microarray was used to explore EAT transcriptoma. The PCSK9 protein levels were measured by Western Blot in EAT and ELISA in plasma. PCSK9 was expressed at both the gene and protein levels in EAT. We found a positive association with EAT thickness and local proinflammatory mediators, in particular, chemokines for monocytes and lymphocytes. No association was found with the circulating PCSK9 level. The expression of PCSK9 in EAT argues that PCSK9 is part of the EAT secretome and EAT inflammation is associated with local PCSK9 expression, regardless of circulating PCSK9 levels. Whether reducing EAT inflammation or PCSK9 local levels may have beneficial effects on EAT metabolism and cardiovascular risk needs further investigations

Hypertension in adult Fabry's disease: is cardiotrophin-1 a diagnostic biomarker?

Background: Cardiotrophin-1 (CT-1), a cytokine produced by cardiomyocytes and non-cardiomyocytes in conditions of stress, can be used as a biomarker of left ventricular hypertrophy and dysfunction in hypertensive patients. Hypertension is one of the main adverse events in the third and last phase of Fabry's disease (FD). We measured CT-1 in order to examine its correlation with the vascular and cardiac alterations at different ages and assess its potential for use as a biomarker of hypertension in FD. Findings: The level of CT-1 was clearly higher in hypertensive adults than in adult FD patients. FD patients show a small, non-significant decrease in plasma CT-1 with age, while in hypertensive patients CT-1 in plasma rises strongly and highly significantly with age. Conclusions: CT-1 can be considered a good biomarker of the progression of hypertension with age, but particular care is needed when following hypertension in FD patients, since CT-1 does not correlate the same way with this disease

Generation of OH radicals at palladium oxide nanoparticle modified electrodes, and scavenging by fluorescent probes and antioxidants

The reduction of palladium oxide nanoparticles in the presence of hydrogen peroxide or dissolved oxygen gives rise to a catalytic reduction current dependent on the hydrogen peroxide concentration or the oxygen concentration. Using terephthalic acid as an OH radical scavenger yielding the fluorescent 2-hydroxyterephthalic acid, we demonstrate that the catalytic current stems from the freshly exposed palladium metal re-oxidation by OH radicals. A kinetic model is presented to account for these catalytic reactions. We also demonstrate that the measurement of the catalytic reduction current in the presence of antioxidant molecules can be used to measure the OH scavenging properties of antioxidants

Correlative study on impaired prostaglandin E2 regulation in EAT and maladaptive cardiac remodeling via EPAC2 and ST2 signaling in overweight CVD subjects

There is recent evidence that the dysfunctional responses of a peculiar visceral fat deposit known as epicardial adipose tissue (EAT) can directly promote cardiac enlargement in the case of obesity. Here, we observed a newer molecular pattern associated with LV dysfunction mediated by prostaglandin E2 (PGE(2)) deregulation in EAT in a cardiovascular disease (CVD) population. A series of 33 overweight CVD males were enrolled and their EAT thickness, LV mass, and volumes were measured by echocardiography. Blood, plasma, EAT, and SAT biopsies were collected for molecular and proteomic assays. Our data show that PGE(2) biosynthetic enzyme (PTGES-2) correlates with echocardiographic parameters of LV enlargement: LV diameters, LV end diastolic volume, and LV masses. Moreover, PTGES-2 is directly associated with EPAC2 gene (r = 0.70, p < 0.0001), known as a molecular inducer of ST2/IL-33 mediators involved in maladaptive heart remodelling. Furthermore, PGE(2) receptor 3 (PTEGER3) results are downregulated and its expression is inversely associated with ST2/IL-33 expression. Contrarily, PGE(2) receptor 4 (PTGER4) is upregulated in EAT and directly correlates with ST2 molecular expression. Our data suggest that excessive body fatness can shift the EAT transcriptome to a pro-tissue remodelling profile, may be driven by PGE(2) deregulation, with consequent promotion of EPAC2 and ST2 signalling

Antioxidant Redox Sensors Based on DNA Modified Carbon Screen-Printed Electrodes

Antioxidant redox sensors based on DNA modified carbon screen-printed electrodes were developed. The carbon ink was doped with TiO2 nanoparticles, onto which double- strand DNA was adsorbed. A redox mediator, namely, tris- 2,2′-bipyridine ruthenium(II) [Ru(bpy)32+] was electro- oxidized on the electrode surface to subsequently oxidize both the adsorbed ds-DNA and the antioxidants in solu- tion. The resulting oxidation damage of the adsorbed ds- DNA was then detected by square wave voltammetry in a second solution containing only Ru(bpy)3Cl2 at a low con- centration (μM). A kinetic model was developed to study the protecting role of antioxidants in aqueous solutions. The electrochemical sensor has been applied to evaluate the redox antioxidant capacity of different molecules

Notch regulates Th17 differentiation and controls trafficking of IL-17 and metabolic regulators within Th17 cells in a context-dependent manner.

Th17 cells play critical roles in host defense and autoimmunity. Emerging data support a role for Notch signaling in Th17 cell differentiation but whether it is a positive or negative regulator remains unclear. We report here that T cell-specific deletion of Notch receptors enhances Th17 cell differentiation in the gut, with a corresponding increase in IL-17 secretion. An increase in Th17 cell frequency was similarly observed following immunization of T cell specific Notch mutant mice with OVA/CFA. However, in this setting, Th17 cytokine secretion was impaired, and increased intracellular retention of IL-17 was observed. Intracellular IL-17 co-localized with the CD71 iron transporter in the draining lymph node of both control and Notch-deficient Th17 cells. Immunization induced CD71 surface expression in control, but not in Notch-deficient Th17 cells, revealing defective CD71 intracellular transport in absence of Notch signaling. Moreover, Notch receptor deficient Th17 cells had impaired mTORC2 activity. These data reveal a context-dependent impact of Notch on vesicular transport during high metabolic demand suggesting a role for Notch signaling in the bridging of T cell metabolic demands and effector functions. Collectively, our findings indicate a prominent regulatory role for Notch signaling in the fine-tuning of Th17 cell differentiation and effector function

Antioxidant Sensors Based on DNA-Modified Electrodes

TiO2/ITO modified electrodes were developed to quantitatively photooxidize adsorbed ds-DNA and to study the effect of antioxidants as ds-DNA protecting agents. TiO2 films are used for efficient ds-DNA immobilization, for ds- DNA oxidation through photogenerated hydroxyl radicals, and as electrodes for amperometric sensing. The films, prepared by a sol-gel process, are deposited on ITO glass electrodes. Damages occurring after ds-DNA oxidation by ROS are detected by adding MB as an intercalant probe and by monitoring the electrochemical reduction current of the intercalated redox probe. The MB electrochemical signal is found to be sensitive enough to monitor ds-DNA structure changes, and the electrochemical sensor has been applied to the evaluation of the antioxidant properties of glutathione and gallic acid

Hypertrophic Epicardial Adipose Tissue is a Source of EPAC Proteins Directly Associate to ST2 Production and Heart Dilation and may be Potential Index of Heart Remodeling in CVDs Patients

Introduction: Epicardial adipose tissue (EAT) is a myocardial fat from which released molecules can directly reach the heart. In pathological conditions, the ubiquitously tissue hypertrophy mediators are the exchange proteins directly activated by cAMP (EPACs), named EPAC1 and EPAC2. In the heart the main protective signalling against detrimental remodelling is the ST2 and IL33 molecules. ST2 exists both as transmembrane receptor (ST2L) and soluble (sST2) form and in case of physiological stretch ST2L bind IL33 promoting anti-fibrotic signals. Contrarily in CVDs, sST2 is up regulated functioning as scavenger of IL33 and promoting heart dilatation. Interesting is that ST2 can be also produced by adipose tissue in normal condition. Due to EPACs properties to induce hyperplasia, our hypothesis is that larger EAT cells may also produce sST2 that can local amplify its detrimental role on myocardium. For these reasons we want to verified in CVDs patients first if larger EAT cells are able to up regulate EPAC proteins and second if EPACs may be associate to sST2 EAT production and heart dilatation. Methods: 50 CVD patients are enrolled and stratified according to EAT median thickness (8mm). plasma and EAT biopsies are collected during surgery. Indexed left ventricular mass (hLVM), end-diastolic posterior wall (EDPW), relative wall thickness (RWT), left ventricular mass (LVM) values are used as cardiac dilatation indexes commonly approved in clinical practice. Gene expression and protein assays are performed to investigate EPACs, ST2, IL33 mRNA and protein production. Results: Our data demonstrated that CVDs patients with EAT >8mm have significantly positive correlation with RWT and they also presented higher EPAC1 and ST2 mRNA and protein levels than CVDs patients 8mm and up-regulated in CVDs patients < 8mm. CVDs patients with hypertrophic EAT both EPAC1 and EPAC2presented positive correlation with hLVM, EDPW, LVM indexes and ST2 mRNA levels. Conclusion: Our results demonstrated that EPACs are directly associate to EAT hyperplasia and sST2 local production suggesting their implication in detrimental heart hyperplasia. From these results we can suggest that EAT thickness can be a potential newer parameter of detrimental heart remodelling in the prevention of CVDs complications