NLRC5, at the Heart of Antigen Presentation.

Nucleotide-binding domain and leucine-rich repeat containing receptors (NLRs) are intracellular proteins mainly involved in pathogen recognition, inflammatory responses, and cell death. Until recently, the function of the family member NLR caspase recruitment domain (CARD) containing 5 (NLRC5) has been a matter of debate. It is now clear that NLRC5 acts as a transcriptional regulator of the major-histocompatibility complex class I. In this review we detail the development of our understanding of NLRC5 function, discussing both the accepted and the controversial aspects of NLRC5 activity. We give insight into the molecular mechanisms, and the potential implications, of NLRC5 function in health and disease.

Possible synergism of physical exercise and ghrelin-agonists in patients with cachexia associated with chronic heart failure.

The occurrence of cachexia of multifactorial etiology in chronic heart failure (CHF) is a common and underestimated condition that usually leads to poor outcome and low survival rates, with high direct and indirect costs for the Health Care System. Recently, a consensus definition on cachexia has been reached, leading to a growing interest by the scientific community in this condition, which characterizes the last phase of many chronic diseases (i.e., cancer, acquired immunodeficiency syndrome). The etiology of cachexia is multifactorial and the underlying pathophysiological mechanisms are essentially the following: anorexia and malnourishment; immune overactivity and systemic inflammation; and endocrine disorders (anabolic/catabolic imbalance and resistance to growth hormone). In this paper, we review the main pathophysiological mechanisms underlying CHF cachexia, focusing also on the broad spectrum of actions of ghrelin and ghrelin agonists, and their possible use in combination with physical exercise to contrast CHF cachexia.

Laparoscopic surgery for coeliac artery compression syndrome: current management and technical aspects.

Objectives: The study aims to assess the feasibility and midterm outcome of trans-peritoneal laparoscopy for coeliac artery compression syndrome (CACS).Design: Retrospective chart review involving four European vascular surgery departments and two surgical teams.Materials and methods: charts for patients who underwent laparoscopy for symptomatic CACS between December 2003 and November 2009 were reviewed. Preoperative computed tomography (CT) angiography and postoperative duplex scan and/or CT angiography were performed.Results: Eleven consecutive patients (nine women) with a median age of 52 years (interquartile range: 42.5-59 years) underwent trans-peritoneal laparoscopy for CACS. All patients had a history of postprandial abdominal pain; weight loss exceeded 10% of the body mass in eight cases. Preoperative CT angiography revealed coeliac trunk stenosis >70% in all cases. One patient had additional aortitis and inferior mesenteric artery occlusion, while another patient presented with an occluded superior mesenteric artery. Two conversions occurred (one difficult dissection and one aorto-hepatic bypass needed for incomplete release of CACS). The median blood loss was 195 ml (range: 50-900 ml) and median operative time was 80 min (interquartile range: 65-162.5 years). Symptoms improved immediately in 10/11 patients (no residual stenosis) while one remained unchanged despite a residual stenosis treated by a percutaneous angioplasty. Symptoms reappeared in one patient due to coeliac axis occlusion. The mean follow-up period was 35 +/- 23 months (range: 12-78 months).Conclusion: Our study demonstrates that trans-peritoneal laparoscopy for treating median arcuate ligament syndrome is safe and feasible. Additional patients and a longer follow-up are needed for long-term assessment of this laparoscopic technique. (C) 2011 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

A next step in adeno-associated virus-mediated gene therapy for neurological diseases: regulation and targeting.

Recombinant adeno-associated virus (rAAV) vectors mediating long term transgene expression are excellent gene therapy tools for chronic neurological diseases. While rAAV2 was the first serotype tested in the clinics, more efficient vectors derived from the rh10 serotype are currently being evaluated and other serotypes are likely to be tested in the near future. In addition, aside from the currently used stereotaxy-guided intraparenchymal delivery, new techniques for global brain transduction (by intravenous or intra-cerebrospinal injections) are very promising. Various strategies for therapeutic gene delivery to the central nervous system have been explored in human clinical trials in the past decade. Canavan disease, a genetic disease caused by an enzymatic deficiency, was the first to be approved. Three gene transfer paradigms for Parkinson's disease have been explored: converting L-dopa into dopamine through AADC gene delivery in the putamen; synthesizing GABA through GAD gene delivery in the overactive subthalamic nucleus and providing neurotrophic support through neurturin gene delivery in the nigro-striatal pathway. These pioneer clinical trials demonstrated the safety and tolerability of rAAV delivery in the human brain at moderate doses. Therapeutic effects however, were modest, emphasizing the need for higher doses of the therapeutic transgene product which could be achieved using more efficient vectors or expression cassettes. This will require re-addressing pharmacological aspects, with attention to which cases require either localized and cell-type specific expression or efficient brain-wide transgene expression, and when it is necessary to modulate or terminate the administration of transgene product. The ongoing development of targeted and regulated rAAV vectors is described.

Molecular autopsy in sudden cardiac death and its implication for families: discussion of the practical, legal and ethical aspects of the multidisciplinary collaboration.

Sudden cardiac death (SCD) is a major cause of premature death in young adults and children in developed countries. Standard forensic autopsy procedures are often unsuccessful in determining the cause of SCD. Post-mortem genetic testing, also called molecular autopsy, has revealed that a non-negligible number of these deaths are a result of inherited cardiac diseases, including arrhythmic disorders such as congenital long QT syndrome and Brugada syndrome. Due to the heritability of these diseases, the potential implications for living relatives must be taken into consideration. Advanced diagnostic analyses, genetic counselling, and interdisciplinary collaboration should be integral parts of clinical and forensic practice. In this article we present a multidisciplinary collaboration established in Lausanne, with the goal of properly informing families of these pathologies and their implications for surviving family members. In Switzerland, as in many other countries, legal guidelines for genetic testing do not address the use of molecular tools for post-mortem genetic analyses in forensic practice. In this article we present the standard practice guidelines established by our multidisciplinary team.

Subclinical Thyroid Dysfunction and the Risk of Heart Failure in Older Persons at High Cardiovascular Risk.

Context: Subclinical thyroid dysfunction is common in older people. However, its clinical importance is uncertain. Objective: Our objective was to determine the extent to which subclinical hyperthyroidism and hypothyroidism influence the risk of heart failure and cardiovascular diseases in older people. Setting and Design: The Prospective Study of Pravastatin in the Elderly at Risk (PROSPER) is an prospective cohort study. Patients: Patients included men and women aged 70-82 yr (n = 5316) with known cardiovascular risk factors or previous cardiovascular disease. Main Outcome Measures: Incidence rate of heart failure hospitalization, atrial fibrillation, and cardiovascular events and mortality according to baseline thyroid status were evaluated. Euthyroid participants (TSH =0.45-4.5 mIU/liter) were compared with those with subclinical hyperthyroidism (TSH <0.45 mIU/liter) and those with subclinical hypothyroidism (TSH ≥4.5 mIU/liter, both with normal free T(4)). Results: Subclinical hyperthyroidism was present in 71 participants and subclinical hypothyroidism in 199 participants. Over 3.2 yr follow-up, the rate of heart failure was higher for subclinical hyperthyroidism compared with euthyroidism [age- and sex-adjusted hazard ratio (HR) = 2.93, 95% confidence interval (CI) = 1.37-6.24, P = 0.005; multivariate-adjusted HR = 3.27, 95% CI = 1.52-7.02, P = 0.002). Subclinical hypothyroidism (only at threshold >10 mIU/liter) was associated with heart failure (age- and sex-adjusted HR = 3.01, 95% CI = 1.12-8.11, P = 0.029; multivariate HR = 2.28, 95% CI = 0.84-6.23). There were no strong evidence of an association between subclinical thyroid dysfunction and cardiovascular events or mortality, except in those with TSH below 0.1 or over 10 mIU/liter and not taking pravastatin. Conclusion: Older people at high cardiovascular risk with low or very high TSH along with normal free T(4) appear at increased risk of incident heart failure.

CARDIAC AND MUSCLE CHANNELOPATHIES: ROLES AND REGULATION OF VOLTAGE-GATED SODIUM CHANNELS

Abstract :The contraction of the heart or skeletal muscles is mainly due to the propagation, through excitable cells, of an electrical influx called action potential (AP). The AP results from the sequential opening of ion channels that generate inward or outward currents through the cell membrane. Among all the channels involved, the voltage-gated sodium channel is responsible for the rising phase of the action potential. Ten genes encode the different isoforms of these channels (from Nav1.1 to Nav1.9 and an atypical channel named NavX). Nav1.4 and Nav1.5 are the main skeletal muscle and cardiac sodium channels respectively. Their importance for muscle and heart function has been highlighted by the description of mutations in their encoding genes SCN4A and SCNSA. They lead respectively to neuromuscular disorders such as myotonia or paralysis (for Nav1.4), and to cardiac arrhythmias that can deteriorate into sudden cardiac death (for Nav1.5).The general aim of my PhD work has been to study diseases linked with channels dysfunction, also called channelopathies. In that purpose, I investigated the function and the regulation of the muscle and cardiac voltage-gated sodium channels. During the two first studies, I characterized the effects of two mutations affecting Nav1.4 and Nav1.5 function. I used the HEK293 model cells to express wild-type or mutant channels and then studied their biophysical properties with the patch-clamp technique, in whole cell configuration. We found that the SCN4A mutation produced complex alterations of the muscle sodium channel function, that could explain the myotonic phenotype described in patients carrying the mutation. In the second study, the index case was an heterozygous carrier of a SCNSA mutation that leads to a "loss of function" of the channel. The decreased sodium current measured with mutated Nay 1.5 channels, at physiological temperature, was a one of the factors that could explain the observed Brugada syndrome. The last project aimed at identifying a new potential protein interacting with the cardiac sodium channel. We found that the protein SAP97 binds the three last amino-acids of the C-terminus of Na,, 1.5. Our results also indicated that silencing the expression of SAP97 in HEK293 cells decreased the sodium current. Sodium channels lacking their three last residues also produced a reduced INa. These preliminary results suggest that SAP97 is implicated in the regulation of sodium channel. Whether this effect is direct or imply the action of an adaptor protein remains to be investigated. Moreover, our group has previously shown that Nav1.5 channels are localized to lateral membranes of cardiomyocytes by the dystrophin multiprotein complex (DMC). This suggests that sodium channels are distributed in, at least, two different pools: one targeted at lateral membranes by DMC and the other at intercalated discs by another protein such as SAP97.These studies reveal that cardiac and muscle diseases may result from ion channel mutations but also from regulatory proteins affecting their regulation.Résumé :La contraction des muscles et du coeur est principalement due à la propagation, à travers les cellules excitables, d'un stimulus électrique appelé potentiel d'action (PA). C'est l'ouverture séquentielle de plusieurs canaux ioniques transmembranaires, permettant l'entrée ou la sortie d'ions dans la cellule, qui est à l'origine de ce PA. Parmi tous les canaux ioniques impliqués dans ce processus, les canaux sodiques dépendant du voltage sont responsables de la première phase du potentiel d'action. Les différentes isoformes de ces canaux (de Nav1.1 à Nav1.9 et NavX) sont codées par dix gènes distincts. Nav1.4 et Nav1.5 sont les principaux variants exprimés respectivement dans le muscle et le coeur. Plusieurs mutations ont été décrites dans les gènes qui codent pour ces deux canaux: SCN4A (pour Nav1.4) et SCNSA (pour Nav1.5). Elles sont impliquées dans des pathologies neuromusculaires telles que des paralysies ou myotonies (SCN4A) ou des arythmies cardiaques pouvant conduire à la mort subite cardiaque (SCNSA).Mon travail de thèse a consisté à étudier les maladies liées aux dysfonctionnements de ces canaux, aussi appelées canalopathies. J'ai ainsi analysé la fonction et la régulation des canaux sodiques dépendant du voltage dans le muscle squelettique et le coeur. A travers les deux premières études, j'ai ainsi pu examiner les conséquences de deux mutations affectant respectivement les canaux Nav1.4 et Nav1.5. Les canaux sauvages ou mutants ont été exprimés dans des cellules HEK293 afin de caractériser leurs propriétés biophysiques par la technique du patch clamp en configuration cellule entière. Nous avons pu déterminer que la mutation trouvée dans le gène SCN4A engendrait des modifications importantes de la fonction du canal musculaire. Ces altérations fournissent des indications nous permettant d'expliquer certains aspects de la myotonie observée chez les membres de la famille étudiée. Le patient présenté dans la deuxième étude était hétérozygote pour la mutation identifiée dans le gène SCNSA. La perte de fonction des canaux Nav1.5 ainsi engendrée, a été observée lors d'analyses à températures physiologiques. Elle représente l'un des éléments pouvant potentiellement expliquer le syndrome de Brugada du patient. La dernière étude a consisté à identifier une nouvelle protéine impliquée dans la régulation du canal sodique cardiaque. Nos expériences ont démontré que les trois derniers acides aminés de la partie C-terminale de Nav1.5 pouvaient interagir avec la protéine SAP97. Lorsque que l'expression de la SAP97 est réduite dans les cellules HEK293, cela induit une baisse importante du courant sodique. De même, les canaux tronqués de leurs trois derniers acides aminés génèrent un flux ionique réduit. Ces résultats préliminaires suggèrent que SAP97 est peut-être impliquée dans la régulation du canal Na,,1.5. Des expériences complémentaires permettront de déterminer si ces deux protéines interagissent directement ou si une protéine adaptatrice est nécessaire. De plus, nous avons préalablement montré que les canaux Nav1.5 étaient localisés au niveau de la membrane latérale des cardiomyocytes par le complexe multiprotéique de la dystrophine (DMC). Ceci suggère que les canaux sodiques peuvent être distribués dans un minimum de deux pools, l'un ciblé aux membranes latérales pax le DMC et l'autre dirigé vers les disques intercalaires par des protéines telles que SAP97.L'ensemble de ces études met en évidence que certaines maladies musculaires et cardiaques peuvent être la conséquence directe de mutations de canaux ioniques, mais que l'action de protéines auxiliaires peut aussi affecter leur fonction.

Comment diminuer son risque cardiovasculaire avec l'alimentation? Rôle des graisses consommées [Nutritional advice to help reduce the cardiovascular risk. Update of the Swiss Federal Office of Public Health's recommendations on fat consumption].

The Swiss Federal Office of Public Health's (FOPH) updated its recommendations on fat consumption in 2013. The report recommends that maximum 10% of the daily caloric intake should come from saturated fatty acids, and the total fat intake should account for 20-35%. There is no limitation to dietary cholesterol consumption. Recent studies have shown that replacing consumption of saturated fatty acids by unsaturated fatty acids is more beneficial in terms of cardiovascular prevention than a low fat diet. The purpose of this article is to review the FOPH recommendations on dietary fat as well as the current evidence about their cardiovascular benefit, and to provide a translation of these scientific recommendations into clinical advice.

Gastrointestinal disease following heart transplantation.

With advances in heart transplantation, a growing number of recipients are at risk of developing gastrointestinal disease. We reviewed our experience with gastrointestinal disease in 92 patients undergoing 93 heart transplants. All had follow-up, with the median time 4.8 years (range 0.5-9.6 years). During the period of the study we progressively adopted a policy of low immunosuppression aiming toward monotherapy with cyclosporine. Nineteen patients (20.6%) developed 28 diseases related to the gastrointestinal tract. Thirteen patients required 18 surgical interventions, five as emergencies: closure of a duodenal ulcer, five cholecystectomies (one with biliary tract drainage), a sigmoid resection for a diverticulitis with a colovesical fistula, a colostomy followed by a colostomy takedown for an iatrogenic colon perforation, appendectomy, two anorectal procedures, and six abdominal wall herniorrhaphies. At the onset of gastrointestinal disease, 8 patients were on standard triple-drug immunosuppression, all of them within 6 months of transplantation; 13 were on double-drug immunosuppression; and 7 were on cyclosporine alone. All the patients with perforations/fistulas were on steroids. Among the 11 infectious or potentially infectious diseases, 10 were on triple- or double-drug immunosuppression. One death, a patient who was on triple-drug immunosuppression, had a postmortem diagnosis of necrotic and hemorrhagic pancreatitis. Except for an incisional hernia following a laparoscopic cholecystectomy, there was no morbidity and, importantly, no septic complications. We concluded that a low immunosuppression policy is likely to be responsible for the low morbidity and mortality of posttransplant gastrointestinal disease, with a lower incidence of viscous perforation/fistula and infectious gastrointestinal disease.

Fructose and metabolic diseases: new findings, new questions.

There has been much concern regarding the role of dietary fructose in the development of metabolic diseases. This concern arises from the continuous increase in fructose (and total added caloric sweeteners consumption) in recent decades, and from the increased use of high-fructose corn syrup (HFCS) as a sweetener. A large body of evidence shows that a high-fructose diet leads to the development of obesity, diabetes, and dyslipidemia in rodents. In humans, fructose has long been known to increase plasma triglyceride concentrations. In addition, when ingested in large amounts as part of a hypercaloric diet, it can cause hepatic insulin resistance, increased total and visceral fat mass, and accumulation of ectopic fat in the liver and skeletal muscle. These early effects may be instrumental in causing, in the long run, the development of the metabolic syndrome. There is however only limited evidence that fructose per se, when consumed in moderate amounts, has deleterious effects. Several effects of a high-fructose diet in humans can be observed with high-fat or high-glucose diets as well, suggesting that an excess caloric intake may be the main factor involved in the development of the metabolic syndrome. The major source of fructose in our diet is with sweetened beverages (and with other products in which caloric sweeteners have been added). The progressive replacement of sucrose by HFCS is however unlikely to be directly involved in the epidemy of metabolic disease, because HFCS appears to have basically the same metabolic effects as sucrose. Consumption of sweetened beverages is however clearly associated with excess calorie intake, and an increased risk of diabetes and cardiovascular diseases through an increase in body weight. This has led to the recommendation to limit the daily intake of sugar calories.

Role of Mitogen-Activated Protein Kinases in Myocardial Ischemia-Reperfusion Injury during Heart Transplantation.

In solid organ transplantation, ischemia/reperfusion (IR) injury during organ procurement, storage and reperfusion is an unavoidable detrimental event for the graft, as it amplifies graft inflammation and rejection. Intracellular mitogen-activated protein kinase (MAPK) signaling pathways regulate inflammation and cell survival during IR injury. The four best-characterized MAPK subfamilies are the c-Jun NH2-terminal kinase (JNK), extracellular signal- regulated kinase-1/2 (ERK1/2), p38 MAPK, and big MAPK-1 (BMK1/ERK5). Here, we review the role of MAPK activation during myocardial IR injury as it occurs during heart transplantation. Most of our current knowledge regarding MAPK activation and cardioprotection comes from studies of preconditioning and postconditioning in nontransplanted hearts. JNK and p38 MAPK activation contributes to myocardial IR injury after prolonged hypothermic storage. p38 MAPK inhibition improves cardiac function after cold storage, rewarming and reperfusion. Small-molecule p38 MAPK inhibitors have been tested clinically in patients with chronic inflammatory diseases, but not in transplanted patients, so far. Organ transplantation offers the opportunity of starting a preconditioning treatment before organ procurement or during cold storage, thus modulating early events in IR injury. Future studies will need to evaluate combined strategies including p38 MAPK and/or JNK inhibition, ERK1/2 activation, pre- or postconditioning protocols, new storage solutions, and gentle reperfusion.

Physiopathology of the embryonic heart (with special emphasis on hypoxia and reoxygenation).

The adaptative response of the developing heart to adverse intrauterine environment such as reduced O2 delivery can result in alteration of gene expression with short- and long-term consequences including adult cardiovascular diseases. The tolerance of the developing heart of acute or chronic oxygen deprivation, its capacity to recover during reperfusion and the mechanisms involved in reoxygenation injury are still under debate. Indeed, the pattern of response of the immature myocardium to hypoxia-reoxygenation differs from that of the adult. This review deals with the structural and metabolic characteristics of the embryonic heart and the functional consequences of hypoxia and reoxygenation. The relative contribution of calcium and sodium overload, pH disturbances and oxidant stress to the hypoxia-induced cardiac dysfunction is examined, as well as various cellular signaling pathways (e.g. MAP kinases) involved in cell survival or death. In the context of the recent advances in developmental cardiology and fetal cardiac surgery, a better understanding of the physiopathology of the stressed developing heart is required.

Indications for cardiovascular magnetic resonance in children with congenital and acquired heart disease: an expert consensus paper of the Imaging Working Group of the AEPC and the Cardiovascular Magnetic Resonance Section of the EACVI.

This article provides expert opinion on the use of cardiovascular magnetic resonance (CMR) in young patients with congenital heart disease (CHD) and in specific clinical situations. As peculiar challenges apply to imaging children, paediatric aspects are repeatedly discussed. The first section of the paper addresses settings and techniques, including the basic sequences used in paediatric CMR, safety, and sedation. In the second section, the indication, application, and clinical relevance of CMR in the most frequent CHD are discussed in detail. In the current era of multimodality imaging, the strengths of CMR are compared with other imaging modalities. At the end of each chapter, a brief summary with expert consensus key points is provided. The recommendations provided are strongly clinically oriented. The paper addresses not only imagers performing CMR, but also clinical cardiologists who want to know which information can be obtained by CMR and how to integrate it in clinical decision-making.