Advances in cardiovascular research

Abstract

The 15th Annual Meeting of the European Council of Cardiovascular Research brought together basic and clinical scientists working in the cardiovascular field in La Colle sur Loup, France. Upfront basic and clinical research addressing the mechanisms of disease, identification of biomarkers or development of new treatments was communicated in 101 presentations, 35 of them as a part of five on-topic oral sessions and three workshops. Three keynote lectures reviewed current knowledge and the latest data about mechanosensitive channels in pressure regulation, cell therapy in cardiovascular disease and mechanisms of cardiovascular risk associated with diabetic nephropathy. This article summarizes highlights of the oral sessions, workshops and keynote lectures.

The European Council for Cardiovascular Research (ECCR) is a society dedicated to frontier basic and clinical research in the fields of hypertension and other cardiovascular diseases (CVDs) [101]. The annual conferences cover a broad range of subjects, including vascular biology, cardiac and renal aspects, cerebrovascular disease, the genetics of CVDs, as well as modern strategies of prevention and therapy. Particular emphasis is placed on the participation of both basic scientists and clinicians to foster the transmission of new scientific findings into clinical practice.

This year’s meeting, which was held during 8–10 October in La Colle sur Loup (France) brought together 159 attendees from 20 countries. Data from 101 abstracts were selected for presentation, 35 of them as oral communications presented in five sessions. Three keynote lectures and three topical workshops (entitled ‘chronopharmacology of cardiovascular drugs’, ‘miRNAs in cardiovascular disease’ and ‘gender differences in cardiovascular medicine’) set the thematic priorities of this year’s meeting and will be reviewed in more depth in this article. Being a rather small but scientifically high-quality meeting held in the scope of a retreat with lecture/poster halls, accommodation and meals at the same remote venue, the ECCR conference is an excellent platform for scientific discussions and for establishing contacts between researchers in a multidisciplinary way.

Scientific sessions

CNS & autonomic nervous function

The first of five on-topic oral sessions dealt with the CNS and the autonomic nervous system in the context of CVD. Two of the five presentations reported data about the effects of direct angiotensin AT2-receptor stimulation with the novel nonpeptide agonist Compound 21 (C21). The first study examined the therapeutic potential of direct AT2-receptor stimulation on mortality and neurological outcome after stroke (middle cerebral artery occlusion with reperfusion) in mice. Katja Schwengel (Charité University Hospital, Berlin, Germany) showed that poststroke pharmacological AT2-receptor stimulation reduced mortality and neurological deficits in this model, probably by inducing neurotrophin synthesis and by an anti-inflammatory action. Neurotrophin synthesis also seemed to be an important mechanism of action of the AT2-receptor agonist C21 in a model of spinal cord injury by contusion in mice, presented by Pawel Namsolleck (Charité University Hospital, Berlin, Germany), in which C21 treatment resulted in improved neurological outcome.

Delayed cerebral ischemia as a result of vasospasms can be a life-threatening complication of subarachnoid hemorrhage (SAH). Gro Povlsen (Glostrup University, Denmark) and coworkers set up a study in male Sprague-Dawley rats in which the therapeutic effect of the MEK1/2 inhibitor U0126 was tested. SAH was induced by injection of a defined volume of blood into the basal cisterns; U0126 was administered intracisternally. Treatment with U0126 abolished SAH-induced arterial contractility and improved neurological outcome. The authors suggested the prevention of SAH-induced upregulation of endothelin (ET_B) and serotonin (5-HT_1B) receptors as the underlying mechanism of action. They further concluded that MEK1/2 inhibition may be a promising future therapeutic approach to prevent SAH-induced cerebral ischemia.

Vascular biology & function

Hydrogen sulfide (H₂S) can act as an endogenous endothelium-dependent vasodilator. To test the hypothesis that ageing-related endothelial dysfunction is related to H₂S, Matt Whiteman (University of Exeter, UK) and colleagues synthesized novel H₂S donors and evaluated their effects on cultured endothelial cells. Their results strengthen the conclusion that slow-releasing H₂S donor compounds can limit endothelial damage during ageing and possibly the associated vascular pathologies.

In vascular smooth muscle, Ca²⁺-activated Cl^- currents (CaCCs) are important for vasomotion. Bestrophin-3 has been shown to be associated with cGMP-dependent CaCCs. Vibeke S Nielsen (University of Aarhus, Denmark) and colleagues tested the hypothesis that transmembrane protein (TMEM)16a is involved in cGMP-independent CaCCs and vasomotion. They used a multidisciplinary approach that included the in vivo transfection of rat mesenteric small arteries with siRNA. The authors conclude that TMEM16a is essential for both types of CaCCs and is important for the synchronization of the contractile activity of vascular smooth muscle cells in the (micro-)arterial wall.

Toll-like receptor 4 (TLR4) is important for cardiac ischemia/reperfusion injury. Daniel Sollinger et al. (Technical University of Munich, Germany) reported on the susceptibility of TLR4^-/- mice to hemodynamic changes and end-organ damage in a setting of chronic nitric oxide synthase inhibition. Their results strengthen the proposal that constitutive downregulation of the innate immune system decreases cardiovascular risk.

Capillary rarefaction (CR) may play a role not only in essential hypertension but also in hypertension of other etiology. Viviek Nama and colleagues (St George’s University of London, UK) tested the hypothesis that CR is involved in the pathogenesis of preeclampsia in pregnant women. They recorded functional and maximal capillary densities on the dorsum of the middle finger at different stages of uncomplicated and complicated human pregnancy, including the postpartum period. This fine example of translational research is the first to show that structural CR precedes the onset of preeclampsia.

The sensory–motor neuropeptide calcitonin gene-related peptide (CGRP) can not only functionally antagonize but also terminate complexes between endothelin (ET)-1 and ET_A receptors on arterial smooth muscle cells. Matthijs Compeer (Maastricht University, The Netherlands) presented molecular pharmacological structure–activity evidence that ET-1 is a bitopic agonist and that ET_A receptors are susceptible to allosteric modulation. Jelly Nelissen (Maastricht University, The Netherlands) and colleagues monitored the cardiac and renal contents of ET-1 and CGRP and the effects of a novel neutral endopeptidase/endothelin-converting enzyme (NEP/ECE) inhibitor during the development of spontaneously hypertensive (SHR) rats. They propose a tight relationship between ET-1 and CGRP during the pathogenesis of chronic hypertension. Two poster presentations also dealt with the interplay between CGRP and ET-1/ET_A. Merlijn Meens (Maastricht University, The Netherlands) and colleagues presented evidence that the CGRP to ET-1/ET_A crosstalk involves G-protein β/γ subunits but not cyclic nucleotides, and Johannes Vogel (University of Zurich, Switzerland) and colleagues presented the very first evidence that the CGRP receptor/ET_A receptor crosstalk is also operational at the level of the prejunctional membrane of sensory–motor nerves.

Clinical studies

The highlight of the clinical session was this year’s winner of the award for the best oral presentation, Chloe Park’s (Imperial College, London, UK) talk about ‘Reproducibility of left ventricular endocardial and epicardial rotation by speckle tracking in elderly individuals’. In this study, 40 patients with an average age of almost 70 years underwent speckle tracking ECG (STE) to assess rotation and twist in the endo- and epicardium. The authors concluded that this novel technique, which may be an early indicator of cardiac disease, is feasible in elderly patients, preferably for measurement of changes in rotation in the endocardium.

Another novel technique for the estimation of cardiovascular risk was presented by Konstantin Kotliar (Munich University of Technology, Germany). In this study, alterations in retinal artery diameter were assessed non-invasively in a time-dependent manner in 34 young volunteers with normal to mildly elevated blood pressure (BP). Retinal pulse wave velocity was calculated from these data and was significantly associated with mean arterial pressure. Since albuminuria was normal in all subjects, the authors conclude that retinal pulse wave velocity may be an earlier marker for BP-induced microvascular changes than microalbuminuria.

Primary aldosteronism (PA) can be treated either by surgical or by medical measures. Maurizio Cesari (University of Padova, Italy) presented a study that enrolled 136 patients with confirmed PA and 142 optimally treated primary hypertensive patients. The study compared outcome in terms of BP and left ventricular hypertrophy. Both surgical and medical treatment lowered BP to the same extent but required more drugs in the medically treated group. Most importantly, despite equally effective BP lowering, left ventricular mass index was significantly reduced only in the surgically treated PA (and the primary hypertensive) group.

Cardiometabolics

Being a good example of ECCR’s credo of bringing basic and clinical science together, in this session three basic and three clinical studies were presented that covered a broad thematic spectrum including the impact of blocking the CD36 fatty acid transporter on insulin resistance, the association of vitamin D levels and asymptomatic coronary artery disease in Type 2 diabetic patients with impaired renal function, vasoactive effects of perivascular adipose tissue in different vascular beds, impairment of insulin-induced microvascular vasomotion in obese patients, signaling pathways in cardioprotective postconditioning and a new inflammatory, cardiometabolic risk factor, soluble urokinase plasminogen activator receptor (suPAR).

Laura Steinbusch (University of Maastricht, The Netherlands) reported that energy supply of cardiomyocytes is mainly provided by glucose, which is transferred into the cell by the transporter GLUT4, and by fatty acids, the transport of which is facilitated by CD36. Blocking CD36 activity by a neutralizing antibody in cardiomyocytes cultured in high-insulin medium prevented the development of insulin resistance as shown by a normalization of palmitate uptake, triglyceride storage and insulin-stimulated glucose uptake. They concluded that pharmacological CD36 blockade may be a future therapeutic concept to improve disturbed cardiac insulin sensitivity.

Two presentations dealt with the impact of exogenous factors on vascular contractility and function. Nele Maenhout (University of Ghent, Belgium) reported on an experimental study in mice comparing the effect of brown, periaortal with white, perimesenteric fat on the regulation of vascular tone during hypoxia. Interestingly, precontracted aortae reacted with vasodilation to hypoxia while mesenteric vessels showed a biphasic response consisting of a short vasoconstriction followed by vasodilation. In both types of vessels, vasorelaxation occurred only in the presence of perivascular fat, while in the mesenteric arteries the presence of the endothelium was essential as well. Applying a whole set of inhibitory experiments, the authors found that ATP-sensitive potassium (K_ATP) channels seem to be involved in the vasorelaxation induced by brown fat, while calcium-activated potassium (K_Ca) channels mediate the vasorelaxant effect of white fat. They further conclude that the adipocyte-derived relaxing factor is crucial for the effect of brown fat, while an endothelium-dependent relaxing factor is necessary for vasodilation in mesenteric vessels surrounded by white fat.

Amy Jonk (Maastricht University, The Netherlands) and colleagues examined the impact of obesity on arterial vasomotion in response to physiological hyperinsulinemia (induced by a glucose drink or a carbohydrate–protein–fat mixed drink; tap water served as a control). They found that meal-induced vasomotion as well as insulin-stimulated glucose disposal were impaired in obese individuals.

Genetics

The extracellular matrix protein biglycan is involved in CVD. Boris Schmitz (University of Münster, Germany) and colleagues showed that the biglycan promoter activity was enhanced by TGF-β1 and TF SP1, and that the two haplotypes were significantly reduced compared with the wild-type haplotype of biglycan.

Cibele Prado (University of São Paulo, Brazil) and colleagues showed that Trypanosoma cruzi, a parasite living in southern America, causes myocarditis with late-onset heart failure. They demonstrated that in mice infected with this parasite, dystrophin loss might be responsible for this late-onset cardiac destruction.

Lisa Golmard (College de France, Paris, France) and colleagues showed that there are specific genotype–phenotype differences in Ehlers–Danlos syndrome patients. They investigated 104 Ehlers–Danlos patients and could identify three different genotypes. Patients with a Gly missense mutation had less typical morphotype and later-onset complications compared with the other two genotypes.

Brigitte Sondemeijer (Academic Medical Center, Amsterdam, The Netherlands) and colleagues demonstrated that there were differences in platelet-specific miRNA expression levels between patients with CVD and healthy controls. Since new biomarkers to better identify subjects at risk for CVD are needed, miRNAs seem to be promising biomarkers in this field.

Livia Lenzini (University of Padova, Italy) and colleagues showed that the Twik-related acid-sensitive potassium channel (TASK)-2 is underexpressed in patients with aldosterone-producing adenomas. This could explain the heterogeneity among aldosterone-producing adenoma patients.

Workshops

Chronopharmacology

Chronopharmacology deals with the question of whether the circadian rhythm or the time of day of drug application (morning or evening) influences the therapeutic efficacy of drugs.

Ramon Hermida (University of Vigo, Spain), who moderated this workshop, gave an introduction to this topic, explaining that when treating hypertensive patients, normalization of night-time BP including night-time BP dipping is at least as important as normalization of daytime BP with regard to reduction of cardiovascular risk. Effective lowering of night-time BP is more easily achieved by evening application of antihypertensives. However, a potential differential reduction of CVD morbidity and mortality risk by a bedtime versus upon-awakening treatment schedule had never been evaluated prospectively. The three presentations of the workshop given by Ramon Hermida and Diana Ayala (University of Vigo, Spain) were mainly based on data obtained in the Monitorización Ambulatoria para Predicción de Eventos Cardiovasculares (i.e., Ambulatory Blood Pressure Monitoring for Prediction of Cardiovascular Events; MAPEC) study [1], and showed that a bedtime schedule in comparison with a schedule in which all medications are ingested upon awakening not only significantly improves BP control, urinary albumin excretion and decreases the prevalence of nondipping, but also significantly reduces CVD morbidity and mortality irrespective of the class of antihypertensive used.

miRNAs in CVD

MicroRNAs are a large subgroup of small, noncoding RNAs. They have been proven to be involved in the post-transcriptional regulation of the expression of protein-coding genes in a wide-range of biological processes and pathologies, including normal development of cardiovascular organs and pathogenesis of CVD.

Anton van Zonneveld (Leiden University, The Netherlands) discussed the relevance of miRNAs as biomarkers for CVD. miRNAs regulate mRNA translation by binding to the 3´-UTR region and inhibiting protein synthesis. They are involved in many tissue-specific processes within the body and exert highly disease-specific actions. For example, miRNA-126 can be found in the endothelium and is involved in angiogenesis. Blocking miRNA-126 expression led to the inhibition of angiogenesis in a rat model with hind leg ischemia.

Coen van Solingen (University of Leiden, The Netherlands) provided more details of the hind leg ischemia rat model and reported that after silencing miRNA-126 with antagomir-126, SDF-1 expression increased, leading to the mobilization of Sca-1⁺ progenitor cells into the circulation.

Esther Creemers (Academic Medical Centrer, Amsterdam, The Netherlands) demonstrated that miRNAs are also involved in many processes related to heart development and heart failure. Recently they demonstrated that miRNA 423-5p was significantly upregulated in subjects with dyspnea on the basis of heart failure compared with subjects with dyspnea without heart failure.

Pia Jeppesen (University of Southern Denmark, Odense, Denmark) and colleagues showed that five miRNAs were upregulated after angiotensin II stimulation in isolated cell culture. They demonstrated that this upregulation involved the Gaq/11 protein and Erk1/2 pathways in isolated cell cultures.

Gender differences in CVD

In this workshop, Jean-François Arnal (Université de Toulouse, France) presented the current knowledge on the signaling pathways activated by the stimulation of the estrogen receptor (ER)-α. The analysis of mouse models targeted for ER-α or ER-β demonstrated a prominent role for ER-α in vascular biology. ER-α directly modulates the transcription of target genes through two activation functions (AFs), AF-1 and AF-2. Using an AF-1-deficient ER-α isoform expressed in the endothelium, the group has shown that AF-2 mediates most of the vasculoprotective actions of estradiol. By contrast, AF-1 is necessary for the estradiol actions in reproductive targets. Thus, it seems possible to uncouple the vasculoprotective and sexual actions with appropriate selective ER modulators.

Francoise Lenfant (Université de Toulouse, France) reported that, surprisingly, although estradiol has a protective effect in most models of CVDs, in a model of skin ischemia (skin flaps) necrosis is reduced and revascularization is promoted by both 17-β estradiol and testosterone. Although the exact mechanism remains to be discovered, a redundancy between the two receptors provides protection against necrosis.

Daniel Henrion (Université d’Angers, France) stated in his presentation that flow (shear stress)-mediated outward arterial remodeling is involved in postischemic revascularization and this process also required ER-α activation, which was demonstrated using a model of chronic change in blood flow in the mesenteric vasculature. This estrogen-dependent remodeling provides females with the capacity to adapt to chronic changes in blood flow in aging, which is not the case in males.

Keynote lectures

Mechanosensitive channels & regulation of pressure

In this keynote lecture, Eric Honoré (Univeristé de Nice Sophia Antipolis, Valbonne, France) explained that specific mechanoreceptors expressed in both the vascular smooth muscle and the endothelium are responsible for adjustment of vascular tone and local blood flow, and for the autoregulation of blood vessels. This pressure-sensitive mechanism, termed ‘the myogenic response’, allows a constant blood flow despite changes in arterial pressure and protects against hypertension-induced injury. This adaptive response to intraluminal pressure involves stretch-dependent activation of depolarizing nonselective cation channels at the plasma membrane followed by recruitment of voltage-gated L-type calcium channels, which are responsible for the calcium influx resulting in smooth muscle contraction. By contrast, opening of stretch-activated hyperpolarizing potassium-selective channels counteracts cell depolarization. Apart from pressure regulation, mechanosensors are also involved in touch sensitivity, hearing and volume regulation. In mammals, several channels participating in vascular mechanotransduction have been defined, the most important of which are specific members of the depolarizing ENaC and the transient receptor potential (TRP) families of ion channels, as well as the hyperpolarizing potassium K_2P and K_ir channel families [2].

Cell therapy: a viable option for treatment of CVD

Douwe Atsma (Leiden University Medical Center, Leiden, The Netherlands) started his lecture with a general introduction into stem cell therapy, including different sources and various kinds of stem cells used in cardiovascular medicine. He then focused on studies in animals and humans testing stem cell therapy in ischemic heart disease (in patients with a history of artery-opening procedures, but no other treatment option) [3], end-stage chronic heart failure and in post-infarct cardiac failure. Atsma pointed out that, although an improvement of cardiac function was achieved by application of stem cells, the magnitude of improvement was only in the range of 3–4%, which is comparable to the effect of standard pharmacological treatment. Furthermore, although histological postmortem analysis revealed that stem cells in fact differentiated into cardiomyocytes, electromechanical coupling was not always present and functional in these revitalized areas, with the consequence that noninnervated and noncontracting cardiomyocytes would sometimes be produced, hindering restoration of ventricular impulse conduction.

He concluded that, despite the fact that stem cell therapy is far from being really understood and certainly needs refinement, it still holds promises for future therapy in cardiology and other disciplines, particularly for those patients refractory to current treatment options.

Mechanisms underlying the excess cardiovascular risk associated with diabetic nephropathy

Diabetic patients with diabetic nephropathy have a strongly increased risk to develop CVD. For early preventive measures and effective therapy, the mechanisms underlying cardiovascular organ damage in patients with diabetic nephropathy have to be better understood. A better understanding may further help to identify biomarkers for early detection of patients at high risk.

Peter Rossing (Steno Diabetes Centre, Gentofte, Denmark) reviewed current knowledge about these pathomechanisms. For example, he reported on a study in diabetic patients with micro- or microalbuminuria in which low levels of vitamin D were strongly associated with asymptomatic coronary artery disease [4]. However, the causal relationship between vitamin D levels and cardiovascular risk is still unclear. The data of this study were also presented by Christel Joergensen (Steno Diabetes Centre, Gentofte, Denmark) in the ‘Cardiometabolic’ session.

Another marker that showed a strong association between plasma levels and CVD in patients with diabetic nephropathy is the soluble receptor for advanced glycation end products (RAGE) [5]. RAGE has been shown to induce the production of adhesion molecules and inflammatory cytokines, thus promoting endothelial and renal dysfunction, low-grade inflammation and unfavorable vascular remodeling, all of which may contribute to the increased cardiovascular risk in diabetes.

A future approach for the identification of biomarkers may involve the proteomic analysis of urine, which is a rich source of biomarkers for a wide range of diseases including CVD.

Conclusion

The 2010 ECCR meeting was a stimulating gathering of basic and clinical scientists communicating and discussing upfront cardiovascular research. The next ECCR meeting will take place in La Colle sur Loup, France, from 30 September to 2 October 2011 [101].

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

No writing assistance was utilized in the production of this manuscript.