Sex-related differences of fatty acid-binding protein 4 and leptin levels in atrial fibrillation.

AIMS: Adiposity plays a key role in the pathogenesis of atrial fibrillation (AF). Our aim was to study the sex differences in adipokines levels according to AF burden. METHODS AND RESULTS: Two independent cohorts of patients were studied: (i) consecutive patients with AF undergoing catheter ablation (n = 217) and (ii) a control group (n = 105). (i) Adipokines, oxidative stress, indirect autonomic markers, and leucocytes mRNA levels were analysed; (ii) correlation between biomarkers was explored with heatmaps and Kendall correlation coefficients; and (iii) logistic regression and random forest model were used to determine predictors of AF recurrence after ablation. Our results showed that: (i) fatty acid-binding protein 4 (FABP4) and leptin levels were higher in women than in men in both cohorts (P < 0.01). In women, FABP4 levels were higher on AF cohort (20 ± 14 control, 29 ± 18 paroxysmal AF and 31 ± 17 ng/mL persistent AF; P < 0.01). In men, leptin levels were lower on AF cohort (22 ± 15 control, 13 ± 16 paroxysmal AF and 13 ± 11 ng/mL persistent AF; P < 0.01). (ii) In female with paroxysmal AF, there was a lower acetylcholinesterase and higher carbonic anhydrase levels with respect to men (P < 0.05). (iii) Adipokines have an important role on discriminate AF recurrence after ablation. In persistent AF, FABP4 was the best predictor of recurrence after ablation (1.067, 95% confidence interval 1-1.14; P = 0.046). CONCLUSION: The major finding of the present study is the sex-based differences of FABP4 and leptin levels according to AF burden. These adipokines are associated with oxidative stress, inflammatory and autonomic indirect markers, indicating that they may play a role in AF perpetuation.

Obesity-Related Genetic Determinants of Heart Failure Prognosis.

PURPOSE: Recent advances in genomics offer a smart option for predicting future risk of disease and prognosis. The objective of this study was to examine the prognostic value in heart failure (HF) patients, of a series of single nucleotide polymorphisms (SNPs). METHODS: A selection of 192 SNPs found to be related with obesity, body mass index, circulating lipids or cardiovascular diseases were genotyped in 191 patients with HF. Anthropometrical and clinical variables were collected for each patient, and death and readmission by HF were registered as the primary endpoint. RESULTS: A total of 53 events were registered during a follow-up period of 438 (263-1077) days (median (IQR)). Eight SNPs strongly related to obesity and HF prognosis were selected as possible prognostic variables. From these, rs10189761 and rs737337 variants were independently associated with HF prognosis (HR 2.295 (1.287-4.089, 95% CI); p = 0.005), whereas rs10423928, rs1800437, rs737337 and rs9351814 were related with bad prognosis only in obese patients (HR 2.142 (1.438-3.192, 95% CI); p = 0.00018). Combined scores of the genomic variants were highly predictive of poor prognosis. CONCLUSIONS: SNPs rs10189761 and rs737337 were identified, for the first time, as independent predictors of major clinical outcomes in patients with HF. The data suggests an additive predictive value of these SNPs for a HF prognosis. In particular for obese patients, SNPs rs10423928, rs1800437, rs737337 and rs9351814 were related with a bad prognosis. Combined scores weighting the risk of each genomic variant could effect interesting new tools to stratify the prognostic risk of HF patients.

Lower epicardial adipose tissue adiponectin in patients with metabolic syndrome.

BACKGROUND: Adiponectin is an anti-atherogenic insulin-sensitizer hormone whose plasma concentration is lower in patients with metabolic syndrome (MS). Visceral adiposity, including epicardial adipose tissue (EAT), is closely related to the development of MS and coronary artery disease (CAD). We sought to study whether EAT and subcutaneous adipose tissue (SAT) adiponectin mRNA levels are similar in patients with and without MS. METHODS: EAT, SAT and blood samples were collected from patients undergoing elective cardiac surgery, for revascularization (n=19) or other procedures (n=27). Plasma adiponectin was measured using ELISA. mRNA was purified and adiponectin mRNA quantified by real time RT-PCR. RESULTS: Mean (SD) age was 71.6 (9.6) years. Patients who met Adult Treatment Panel III MS criteria (n=29) presented lower plasma adiponectin concentrations (11.2 (7.4) vs. 19.6 (8.4) mg/l, P=0.004), lower EAT adiponectin mRNA (12.7 (3.0) vs. 15.1 (3.7) a.u., P=0.029) and similar SAT adiponectin mRNA levels (13.7 (4.2) vs. 15.6 (5.7) a.u., P=0.25) than those without MS. After adjusting for age, sex, CAD and heart failure, the association with MS remained statistically significant for plasma adiponectin (OR 0.862 (0.762-0.974)), was of borderline significance for EAT adiponectin mRNA (OR 0.796 (0.630-1.005)) and not significant for SAT adiponectin mRNA (OR 0.958 (0.818-1.122)). Patients in the lower quartiles of EAT adiponectin mRNA and plasma adiponectin presented a higher mean of components of the MS. CONCLUSIONS: Subjects with MS present lower EAT adiponectin mRNA levels than those without MS, whereas SAT adiponectin mRNA levels do not seem to differ between both groups. EAT might be the link between MS and its atherothrombotic cardiac complications.

Diabetic and nondiabetic patients express similar adipose tissue adiponectin and leptin levels.

OBJECTIVE: Epicardial adipose tissue (EAT) is an interesting visceral fat pad with a particular location. EAT and subcutaneous adipose tissue (SAT) produce a wide range of adipokines. Some of them, including adiponectin and leptin, can influence the risk of development of diabetes and other associated metabolic and cardiovascular conditions. We sought to assess whether EAT and SAT adiponectin and leptin expression levels are different in diabetic patients with respect to nondiabetic subjects. SUBJECTS AND METHODS: We collected samples of EAT from 120 patients and samples of SAT from 88 of the same group of patients undergoing elective cardiac surgery for coronary artery bypass grafting (n=69) or other procedures (n=51). After RNA isolation, adiponectin and leptin expression levels were analyzed by real-time reverse transcriptase PCR. Plasma levels were determined in small subsamples of subjects. Baseline clinical and treatment data were obtained from medical records. RESULTS: A total of 45 diabetic and 75 nondiabetic subjects were included in the study. Mean (s.d.) age was 70.1 (7.8) years and there were 32% women. EAT and SAT adiponectin and leptin mRNA expression levels were similar in the diabetic and the nondiabetic groups (EAT adiponectin 14.4 (4.3) vs 14.6 (3.4) arbitrary units (a.u.), P=0.79; SAT adiponectin 15.6 (4.7) vs 15.1 (3.9), P=0.54; EAT leptin 9.3 (interquartile range 2.5) vs 9.5 (1.9) a.u., P=0.72; SAT leptin 9.9 (3.6) vs 10.0 (2.5) a.u., P=0.96). These findings persisted after stratification for sex and coronary artery disease. Logistic regression models including possible confounders and a combination of diabetes and impaired fasting glucose as a dependent variable led to similar results. Plasma adiponectin levels were lower in diabetic patients, whereas leptin levels showed a nonsignificant trend. CONCLUSION: Diabetic and nondiabetic subjects express similar EAT and SAT adiponectin and leptin levels. Counter-regulatory mechanisms of adiponectin and leptin expression in patients with established diabetes might partly account for these findings.

Epicardial adipose tissue expression of adiponectin is lower in patients with hypertension.

Low plasma adiponectin levels are related to a higher risk of development of metabolic and cardiovascular disorders, including hypertension (HT). To date, there have been no studies supporting the relationship between epicardial adipose tissue (EAT) expression of adiponectin and HT. We collected samples of EAT from 116 patients undergoing elective cardiac surgery, mostly for coronary artery bypass grafting (n = 54), valve surgery (n = 49) or both (n = 12). Samples of subcutaneous adipose tissue (SAT) were harvested from 85 patients. After RNA isolation, the expression of adiponectin was analysed by real-time retrotranscriptase (RT)-PCR. Baseline clinical data were obtained from medical records. The diagnosis of HT was established mostly by the patients' general physicians following current guidelines. We included 84 hypertensive and 32 non-hypertensive patients. Mean (+/-s.d.) age was 70.3+/-7.9 years. EAT expression levels of adiponectin were lower in hypertensives (14.0+/-3.6 vs 15.3+/-3.6 arbitrary units (a.u.), P = 0.06). This difference was statistically significant (odds ratio (OR) 0.828 per a.u., P = 0.020) after adjustment for age, gender, body mass index, diabetes mellitus, heart failure, coronary artery disease (CAD), total cholesterol and triglyceride levels. However, SAT adiponectin mRNA levels were similar in hypertensive and non-hypertensive patients (15.3+/-4.2 vs 15.3+/-5.0 a.u., P > 0.99). Adjustment for potential confounding factors hardly altered this result. Our findings indicate that EAT expression of adiponectin may be associated with HT status independently of CAD or other comorbidities, whereas SAT expression does not. These results support the hypothesis that EAT is actively implicated in global cardiovascular risk, describing its association with HT.

Lordosis manoeuvre in the diagnosis of lumbar facet syndrome. / Efectividad de la maniobra lordosante en el diagnóstico del síndrome facetario lumbar.

UNLABELLED: In lumbar pain patients an aetiopathogenic diagnosis leads to a better management. When there are alarm signs, they should be classified on an anatomical basis through anamnesis and physical examination. A significant group is of facet origin (lumbar facet syndrome [LFS]), but the precise clinical diagnosis remains cumbersome and time-consuming. In clinical practice it is observed that patients with an advanced degenerative disease do not perform extension or rotation of their lumbar spine when prompted to extend it, but rather knee flexion, making the manoeuvre meaningless. For this reason, a new simple and quick clinical test was developed for the diagnosis of lumbar facet syndrome, with a facet block-test as a confirmation. HYPOTHESIS: The new test is better than a classic one in the diagnosis of facet syndrome, and probably even better than imaging studies MATERIALS AND METHODS: A prospective study was conducted on a series of 68 patients (01/01/2012-30/06/2013). A comparison in between: classic manoeuvre (CM), imaging diagnostics (ID), and the new lordosis manoeuvre (LM) test. Examination and block test by one author, and evaluation of results by another one. EXCLUSION CRITERIA: Deformity and instability. using a physical. OBJECTIVE: To determine the effectiveness of a new clinical test (LM) for the diagnosis of LFS (as confirmed by a positive block-test of medial branch of dorsal ramus of the lumbar root, RMRDRL). STATISTICS: R package software. RESULTS: The LM was most effective (p<.0001; Kappa 0.524, p<.001). There was no correlation between either the CM or ID and the block-test results (Kappa, CM: 0.078; p=.487, and ID: 0.195; p=.105). There was a correlation between ID (CAT/MR) and LM (p=.024; Kappa 0.289 p=.014), although not with CM. There was no correlation between ID (plain X-rays) and CM or LM. CONCLUSIONS: A new test for diagnosis of LFS is presented that is reliable, quick, and simple. Clinical examination is more reliable than imaging test for the diagnosis of LFS.

Leptin promotes the tyrosine phosphorylation of SHC proteins and SHC association with GRB2.

The identification and characterization of proteins that become tyrosine phosphorylated in response to growth factor stimulation is critical for furthering our understanding of the signal transduction pathways involved in the regulation of cell proliferation, differentiation as well as metabolic activities. In this report, we demonstrate for the first time, that leptin is able to induce the tyrosine phosphorylation of the SH(2) containing protein SHC. These studies have been carried out on a human embryonic cell line (HEK 293) transfected with the cDNA encoding for the long form of the leptin receptor and stably expressing the receptor itself. We also shown that upon tyrosine phosphorylation, SHC associated with the adaptor protein, Grb(2). The formation of this complex may directly link tyrosine phosphorylation events to Ras activation and may be a critical step in proliferation and/or differentiation of cells. In conclusion, these results indicate that leptin receptor, after binding the ligand, activates several pathways for signal transduction that might lead to mitogenic effect.

Elevated serum leptin concentrations induced by experimental acute inflammation.

Leptin is a pleiotropic hormone that regulates body weight and energy expenditure. Recent findings suggest that leptin may be involved in acute and/or chronic inflammation, however only limited results are available describing the effects of in vivo models of acute inflammation on leptin secretion. The aim of this study was to evaluate serum leptin levels in response to two well-established models of acute inflammation in rats: carrageenan rat paw induced oedema and carrageenan induced pleurisy. Our results clearly show that leptin levels rise in rats in which both oedema and pleurisy were induced. Serum leptin levels in carrageenan induced paw oedema were 3.86+/-0.16 microg/L in comparison to 1.83+/-0.17 microg/L of control animals (p<0.001). A similar result was observed in carrageenan induced pleurisy animals in which leptin levels were 4.87+/-0.27 microg/L in comparison to 2.19+/-0.16 microg/L of control animals (p<0.001). The increase in leptin levels induced following carrageenan-induced pleurisy appears to be dependent on adrenal function and it is markedly blunted in adrenalectomized rats. Leptin levels in carrageenan induced pleurisy, carried out on adrenalectomized rats, were lower than intact inflamed animals, suggesting a possible involvement of endogenous glucocorticoids. In summary the results here presented show that: a) an elevated plasma leptin concentration was induced during experimental models of inflammation b) this increase is mediated to a large extent by glucocorticoids. In conclusion, acute experimental models of inflammation are associated with changes in circulating leptin suggesting a possible involvement of this hormone in the anorexia/cachexia that is frequently associated with inflammatory processes. Furthermore, our data indicate the existence of a feedback loop among glucocorticoids and leptin which might contribute to the immune response to lace the inflammatory process.

Spectrophotometric determination of Mo(VI) in steel using a homogeneous ternary solvent system after single-phase extraction.

An alternative procedure for the determination of Mo(VI) with thiocyanate is proposed. According to this procedure, Mo(VI) is extracted with alpha-benzoinoxime by single-phase extraction in a water/ethanol/chloroform homogeneous ternary solvent system at a nominal pH of 2 and then is spectrophotometrically determined, after separation from the matrix in a similar solvent mixture. The determination is performed by forming a homogeneous phase using the solvent containing the extracted metal as one of the components of the reactional solvent system, eliminating the time-consuming metal complex destruction step. Under these experimental conditions, the calibration graph is linear up to 8.00 mug ml(-1), according to the equation A=0.005+0.143C(Mo(VI)) (r(2)=0.9999). Using the experimental conditions described, the absorbance readings are stable for periods up to 18 h. The interference of the most common interfering species for this method can be prevented by adding Fe(2+) and H(2)PO(4)(-) to the solvent system prior to the extraction step. The accuracy of the proposed method was evaluated by comparing with standard samples determined by atomic absorption measurements with background correction.

Receptor for advanced glycation end-products expression in subcutaneous adipose tissue is related to coronary artery disease.

OBJECTIVE: Obesity, a risk factor for coronary artery disease (CAD), is associated with inflammation and reactive oxygen species (ROS) production, while advanced glycation end-products, through their receptor (AGER or RAGE), play an important role on these processes. The aim of this study was to analyze the expression levels of RAGE, NADPH oxidase subunits, and catalase in adipose tissue in relation with CAD. DESIGN AND METHODS: Patients undergoing heart surgery were included in two groups: with and without CAD. Epicardial adipose tissue (EAT) and subcutaneous adipose tissue (SAT) biopsies were analyzed for gene expression by RT-quantitative PCR, immunohistochemistry, or western blot. RESULTS: RAGE mRNA and protein expression in SAT from patients with CAD was lower than in patients without CAD. However, there was no change in EAT from patients with or without CAD. P22-PHOX and RAGE gene expression were higher in EAT than in SAT, whereas catalase mRNA levels were lower. NADPH oxidase subunits and catalase mRNA expression were not influenced by CAD. Whereas NADPH oxidase-dependent oxidative response of SAT and EAT to lipid circulating levels could be different; glycemic levels were not related with the analyzed genes expression. CONCLUSIONS: This study demonstrates that RAGE expression in SAT, but not in EAT, is down-regulated in patients with CAD with respect to those without CAD. Although changes were not observed for NADPH oxidase subunits or catalase expression between CAD and non-CAD patients, a possible relationship between ROS production and RAGE expression in adipose tissues cannot be ruled out.

No direct effect of creatine phosphate on the cross-bridge cycle in cardiac myofibrils.

Creatine phosphate (CP) and creatine kinase (CK) are involved in the rapid resynthesis of ATP and thereby serve to stabilize ATP concentration and to maintain free ADP low inside cardiac muscle cells during contraction. Recently, it has been suggested from experiments in permeabilized multicellular preparations that CP/CK also regulate the kinetics of the actomyosin interaction (cross-bridge cycle) and may explain contractile dysfunction, for instance, during ischemia. However, the reported effects of CP/CK may be confounded by diffusion limitations in multicellular preparations in which inorganic phosphate (P(i)) and ADP may significantly accumulate during contraction. To test this hypothesis, we measured force production and the rates of force development (k (ACT) and k (TR)) in isolated cardiac myofibrils, in which rapid concentration changes of Ca(2+), CP/CK, and P(i) were imposed using a rapid perfusion change system. The results showed that CP/CK did not influence maximum force-generating capacity, whereas P(i) markedly reduced force and increased the rates of force development. No effects of CP/CK on the rates of force development were observed, consistent with the notion that CP/CK do not exert a direct effect on the actomyosin interaction.

Alterations in contractile protein composition and function in human atrial dilatation and atrial fibrillation.

The cellular mechanisms responsible for contractile dysfunction associated with atrial fibrillation (AF) are still poorly understood. Atrial fibrillation is often preceded by atrial dilatation. This study aimed to explain contractile alterations associated with AF and their relation to atrial dilatation, by studying the relationships between atrial dimensions, contractile protein composition, force production and Ca(2+)-sensitivity. Force development was determined in mechanically isolated single skinned cardiomyocytes from right atrial appendages from patients with sinus rhythm without (SR;n=9), or with atrial dilation (SR+AD;n=11) or atrial fibrillation (AF;n=16). Echocardiography showed that, compared to the SR group, mean right atrial dimensions were increased by 18% and 35% in the SR+AD and AF group, respectively (P<0.05). Protein composition was determined by 1- and 2-dimensional gel electrophoresis. Compared to the SR group, the AF group exhibited: a reduction in the kinetics of force redevelopment (K(tr)) in isolated atrial cardiomyocytes, enhanced protein expression of the slow myosin heavy chain isoform (beta-MHC), an increase in troponin T (TnT) phosphorylation and a marked increase (70%) of the cytoskeletal protein desmin. Significant correlations were observed between the right atrial major axis (RA(major)) and beta-MHC expression as well as the desmin/actin ratio. Our findings indicate that dilatation may influence cardiomyocyte stability through altered desmin expression, but that it does not predispose to the alterations in contractile function observed in AF.

Myosin heavy chain composition and the economy of contraction in healthy and diseased human myocardium.

Changes in myosin heavy chain (MHC) isoform expression and protein composition occur during cardiac disease and it has been suggested that even a minor shift in MHC composition may exert a considerable effect on myocardial energetics and performance. Here an overview is provided of the cellular basis of the energy utilisation in cardiac tissue and novel data are presented concerning the economy of myocardial contraction in diseased atrial and ventricular human myocardium. ATP utilisation and force development were measured at various Ca(2+) concentrations during isometric contraction in chemically skinned atrial trabeculae from patients in sinus rhythm (SR) or with chronic atrial fibrillation (AF) and in ventricular muscle strips from non-failing donor or end-stage failing hearts. Contractile protein composition was analysed by one-dimensional gel electrophoresis. Atrial fibrillation was accompanied by a significant shift from the fast alpha-MHC isoform to the slow beta-MHC isoform, whereas both donor and failing ventricular tissue contained almost exclusively the beta-MHC isoform. Simultaneous measurements of force and ATP utilisation indicated that economy of contraction is preserved in atrial fibrillation and in end-stage human heart failure.