Explore the vast range of titles available.

The inhibition, in mice, of the phosphodiesterase PDE9A, which specifically regulates natriuretic-peptide-coupled cGMP signalling, is independent of nitric oxide and is upregulated in failing human hearts, and can reverse pre-established stress-induced heart disease. A new treatment for heart disease Work in animals has shown that inhibition of phosphodiesterase type 5A (PDE5A) with, for example, Viagra, can protect the heart from pathological stress by preventing the degradation of nitric-oxide-generated cGMP. However, nitric oxide signalling is often depressed in cardiovascular disease, potentially explaining the disappointing results of PDE5A inhibition in clinical trials. David Kass and colleagues now identify an alternative target, PDE9A, which specifically regulates natriuretic-peptide-coupled cGMP signalling, and is independent of nitric oxide. They show that PDE9A is upregulated in failing human hearts and that its inhibition in mice can reverse pre-established stress-induced heart disease. PDE9A inhibitors seem to be well tolerated in humans and are being investigated in clinical trials for neurocognitive disease. The new results suggest that these inhibitors may also find an application in heart disease. Cyclic guanosine monophosphate (cGMP) is a second messenger molecule that transduces nitric-oxide- and natriuretic-peptide-coupled signalling, stimulating phosphorylation changes by protein kinase G. Enhancing cGMP synthesis or blocking its degradation by phosphodiesterase type 5A (PDE5A) protects against cardiovascular disease 1 , 2 . However, cGMP stimulation alone is limited by counter-adaptions including PDE upregulation 3 . Furthermore, although PDE5A regulates nitric-oxide-generated cGMP 4 , 5 , nitric oxide signalling is often depressed by heart disease 6 . PDEs controlling natriuretic-peptide-coupled cGMP remain uncertain. Here we show that cGMP-selective PDE9A (refs 7 , 8 ) is expressed in the mammalian heart, including humans, and is upregulated by hypertrophy and cardiac failure. PDE9A regulates natriuretic-peptide- rather than nitric-oxide-stimulated cGMP in heart myocytes and muscle, and its genetic or selective pharmacological inhibition protects against pathological responses to neurohormones, and sustained pressure-overload stress. PDE9A inhibition reverses pre-established heart disease independent of nitric oxide synthase (NOS) activity, whereas PDE5A inhibition requires active NOS. Transcription factor activation and phosphoproteome analyses of myocytes with each PDE selectively inhibited reveals substantial differential targeting, with phosphorylation changes from PDE5A inhibition being more sensitive to NOS activation. Thus, unlike PDE5A, PDE9A can regulate cGMP signalling independent of the nitric oxide pathway, and its role in stress-induced heart disease suggests potential as a therapeutic target.

Chronic neurohormonal and mechanical stresses are central features of heart disease. Increasing evidence supports a role for the transient receptor potential canonical channels TRPC3 and TRPC6 in this pathophysiology. Channel expression for both is normally very low but is increased by cardiac disease, and genetic gain- or loss-of-function studies support contributions to hypertrophy and dysfunction. Selective small-molecule inhibitors remain scarce, and none target both channels, which may be useful given the high homology among them and evidence of redundant signaling. Here we tested selective TRPC3/6 antagonists (GSK2332255B and GSK2833503A; IC ₅₀, 3–21 nM against TRPC3 and TRPC6) and found dose-dependent blockade of cell hypertrophy signaling triggered by angiotensin II or endothelin-1 in HEK293T cells as well as in neonatal and adult cardiac myocytes. In vivo efficacy in mice and rats was greatly limited by rapid metabolism and high protein binding, although antifibrotic effects with pressure overload were observed. Intriguingly, although gene deletion of TRPC3 or TRPC6 alone did not protect against hypertrophy or dysfunction from pressure overload, combined deletion was protective, supporting the value of dual inhibition. Further development of this pharmaceutical class may yield a useful therapeutic agent for heart disease management.

Normal circulatory function is a key determinant of disease-free life expectancy (healthspan). Indeed, pathologies affecting the cardiovascular system, which are growing in prevalence, are the leading cause of global morbidity, disability and mortality, whereas the maintenance of cardiovascular health is necessary to promote both organismal healthspan and lifespan. Therefore, cardiovascular ageing might precede or even underlie body-wide, age-related health deterioration. In this Review, we posit that eight molecular hallmarks are common denominators in cardiovascular ageing, namely disabled macroautophagy, loss of proteostasis, genomic instability (in particular, clonal haematopoiesis of indeterminate potential), epigenetic alterations, mitochondrial dysfunction, cell senescence, dysregulated neurohormonal signalling and inflammation. We also propose a hierarchical order that distinguishes primary (upstream) from antagonistic and integrative (downstream) hallmarks of cardiovascular ageing. Finally, we discuss how targeting each of the eight hallmarks might be therapeutically exploited to attenuate residual cardiovascular risk in older individuals.In this Review, Kroemer and colleagues describe eight molecular hallmarks of cardiovascular ageing: disabled macroautophagy, loss of proteostasis, genomic instability, epigenetic alterations, mitochondrial dysfunction, cell senescence, dysregulated neurohormonal signalling and inflammation. Therapeutically targeting these hallmarks might attenuate residual cardiovascular risk in older individuals.

Inflammation plays a central role in cardiovascular diseases (CVD). One pathway under investigation is the innate immune DNA sensor cyclic GMP-AMP synthase (cGAS) and its downstream receptor stimulator of interferon genes (STING). cGAS-STING upregulates type I interferons in response to pathogens. Recent studies show that also self-DNA may activate cGAS-STING, for instance, DNA released from nuclei or mitochondria during obesity or myocardial infarction. Here, we focus on emerging evidence describing the interaction of cGAS-STING with cardiovascular risk factors and disease. We also touch on translational therapeutic opportunities and potential further investigations.

The prevalence of heart failure increases in the aging population and following myocardial infarction (MI), yet the extracellular matrix (ECM) remodeling underpinning the development of aging- and MI-associated cardiac fibrosis remains poorly understood. A link between inflammation and fibrosis in the heart has long been appreciated, but has mechanistically remained undefined. We investigated the expression of a novel protein, extracellular matrix protein 1 (ECM1) in the aging and infarcted heart. Young adult (3-month old) and aging (18-month old) C57BL/6 mice were assessed. Young mice were subjected to left anterior descending artery-ligation to induce MI, or transverse aortic constriction (TAC) surgery to induce pressure-overload cardiomyopathy. Left ventricle (LV) tissue was collected early and late post-MI/TAC. Bone marrow cells (BMCs) were isolated from young healthy mice, and subject to flow cytometry. Human cardiac fibroblast (CFb), myocyte, and coronary artery endothelial & smooth muscle cell lines were cultured; human CFbs were treated with recombinant ECM1. Primary mouse CFbs were cultured and treated with recombinant angiotensin-II or TGF-β1. Immunoblotting, qPCR and mRNA fluorescent in-situ hybridization (mRNA-FISH) were conducted on LV tissue and cells. ECM1 expression was upregulated in the aging LV, and in the infarct zone of the LV early post-MI. No significant differences in ECM1 expression were found late post-MI or at any time-point post-TAC. ECM1 was not expressed in any resident cardiac cells, but ECM1 was highly expressed in BMCs, with high ECM1 expression in granulocytes. Flow cytometry of bone marrow revealed ECM1 expression in large granular leucocytes. mRNA-FISH revealed that ECM1 was indeed expressed by inflammatory cells in the infarct zone at day-3 post-MI. ECM1 stimulation of CFbs induced ERK1/2 and AKT activation and collagen-I expression, suggesting a pro-fibrotic role. ECM1 expression is increased in ageing and infarcted hearts but is not expressed by resident cardiac cells. Instead it is expressed by bone marrow-derived granulocytes. ECM1 is sufficient to induce cardiac fibroblast stimulation in vitro. Our findings suggest ECM1 is released from infiltrating inflammatory cells, which leads to cardiac fibroblast stimulation and fibrosis in aging and MI. ECM1 may be a novel intermediary between inflammation and fibrosis.

Cerebral white matter hyperintensities (WMH) have been associated with subclinical atherosclerosis including coronary artery calcification (CAC). However, previous studies on this association are limited by only cross-sectional analysis. We aimed to explore the relationship between WMH and CAC in elderly individuals both cross-sectionally and longitudinally. The study population consisted of elderly stroke- and dementia-free participants from the community-based Austrian Stroke Prevention Family Study (ASPFS). WMH volume and CAC levels (via Agatston score) were analyzed at baseline and after a 6-year follow-up period. Of 324 study participants (median age: 68 years), 115 underwent follow-up. Baseline WMH volume (median: 4.1 cm 3 ) positively correlated with baseline CAC levels in multivariable analysis correcting for common vascular risk factors (p = 0.010). While baseline CAC levels were not predictive for WMH progression (p = 0.447), baseline WMH volume was associated CAC progression (median Agatston score progression: 27) in multivariable analysis (ß = 66.3 ± 22.3 [per cm 3 ], p = 0.004). Ten of 11 participants (91%) with severe WMH (Fazekas Scale: 3) at baseline showed significant CAC progression > 100 during follow-up. In this community-based cohort of elderly individuals, WMH were associated with CAC and predictive of its progression over a 6-year follow-up. Screening for coronary artery disease might be considered in people with more severe WMH.

In this multicenter study we investigated whether echocardiography-derived left ventricular global longitudinal strain (LV GLS), an indicator of myocardial fibrosis, independently predicts a positive genotype in hypertrophic cardiomyopathy (HCM). We performed a cross-sectional analysis including HCM patients with genetic testing results and echocardiographic data from two Austrian HCM registries. Echocardiographic parameters were measured in post-processing analysis by a blinded investigator. Among 125 patients with HCM, a positive genotype was present in 39%. Worse LV GLS was associated with a positive genotype in univariate analysis (Odds Ratio [OR] 95% CI 1.141, 1.018–1.279, p  = 0.023). In multivariate regression analysis adjusted for genotype predictors (age at diagnosis < 45 years, arterial hypertension, positive family history of HCM, maximal to posterior wall thickness [MWTH: PWTH], reverse curve septal phenotype), the reverse curve septal phenotype remained as a single independent predictor of genotype-positive HCM (OR 6.948, 2.342–20.614, p  < 0.001). Adding LV GLS to established Toronto and Mayo genotype prediction scores did not improve their performance. To conclude, worse LV GLS was not independently associated with genotype-positive HCM and did not improve the diagnostic yield of genetic testing in HCM in a multivariate model. Our study highlights the reverse curve septal phenotype as the strongest genotype predictor in HCM.

Background Type 2 diabetes mellitus (T2DM) predisposes patients to adverse cardiac remodeling even before the development of cardiomyopathic symptoms. The mechanisms for such early perturbations remain elusive. Given that myosin is the most abundant and energy‑demanding cardiac protein, we tested whether its regulation is impaired even in non‑failing human diabetic hearts. Methods Left ventricular strips were individually isolated from organ donors with and without T2DM. These strips were then subjected to a combination of acetyl‑proteomics, X-ray diffraction, in-silico simulations and Mant-ATP chase experiments. Results Strikingly, we identified nine cardiac myosin (MYH7) lysine residues with significantly altered acetylation levels in T2DM ventricles, many of which were predicted to destabilize the protein coiled‑coil regions. Consistently, X‑ray diffraction revealed increased lattice spacing and a shift towards myosin ON‑state in T2DM tissue. However, and surprisingly, Mant‑ATP chase analyses indicated no bioenergetic consequences at the myosin level. Conclusions Human T2DM myocardium exhibits early, site‑specific myosin acetylations that destabilize myosin structural OFF‑state. This myosin ‘preload’ remodeling occurs at no energetic cost and may constitute a potential early marker of latent myocardial vulnerability in T2DM.

Despite the high prevalence of heart failure in the western world, there are few effective treatments. Fibulin-3 is a protein involved in extracellular matrix (ECM) structural integrity, however its role in the heart is unknown. We have demonstrated, using single cell RNA-seq, that fibulin-3 was highly expressed in quiescent murine cardiac fibroblasts, with expression highest prior to injury and late post-infarct (from ~ day-28 to week-8). In humans, fibulin-3 was upregulated in left ventricular tissue and plasma of heart failure patients. Fibulin-3 knockout ( Efemp1 −/− ) and wildtype mice were subjected to experimental myocardial infarction. Fibulin-3 deletion resulted in significantly higher rate of cardiac rupture days 3–6 post-infarct, indicating a weak and poorly formed scar, with severe ventricular remodelling in surviving mice at day-28 post-infarct. Fibulin-3 knockout mice demonstrated less collagen deposition at day-3 post-infarct, with abnormal collagen fibre-alignment. RNA-seq on day-3 infarct tissue revealed upregulation of ECM degradation and inflammatory genes, but downregulation of ECM assembly/structure/organisation genes in fibulin-3 knockout mice. GSEA pathway analysis showed enrichment of inflammatory pathways and a depletion of ECM organisation pathways. Fibulin-3 originates from cardiac fibroblasts, is upregulated in human heart failure, and is necessary for correct ECM organisation/structural integrity of fibrotic tissue to prevent cardiac rupture post-infarct.

AimsLatent cytomegalovirus (CMV) infection is associated with adverse cardiovascular outcomes. Virus-specific CX3CR1+ effector memory T-cells may be instrumental in this process due to their pro-inflammatory properties. We investigated the role of CX3CR1 (fractalkine receptor) in CMV-related lymphocyte kinetics and cardiac remodeling in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI).Methods and ResultsWe retrospectively analysed lymphocyte count, troponin, and survival in 4874 STEMI/pPCI patients, evaluated lymphocyte kinetics during reperfusion in a prospective cohort, and obtained sequential cardiac MRI (cMRI) to assess remodeling. Pre-reperfusion lymphopenia independently predicted mortality at 7.5 years. Prior to reperfusion, CCR7+ T-lymphocytes appeared to be depleted. After reperfusion, T-lymphocytes expressing CX3CR1 were depleted predominantly in CMV-seropositive patients. During ischaemia/reperfusion, a drop in CX3CR1+ T-lymphocytes was significantly linked with microvascular obstruction in CMV+ patients, suggesting increased fractalkine-receptor interaction. At 12 weeks, CMV+ patients displayed adverse LV remodeling.ConclusionWe show that lymphopenia occurs before and after reperfusion in STEMI by different mechanisms and predicts long-term outcome. In CMV+ patients, increased fractalkine induction and sequestration of CX3CR1+ T-cells may contribute to adverse remodeling, suggesting a pro-inflammatory pathomechanism which presents a novel therapeutic target.