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The relationship between oxidative stress and cardiac stiffness is thought to involve modifications to the giant muscle protein titin, which in turn can determine the progression of heart disease. In vitro studies have shown that S-glutathionylation and disulfide bonding of titin fragments could alter the elastic properties of titin; however, whether and where titin becomes oxidized in vivo is less certain. Here we demonstrate, using multiple models of oxidative stress in conjunction with mechanical loading, that immunoglobulin domains preferentially from the distal titin spring region become oxidized in vivo through the mechanism of unfolded domain oxidation (UnDOx). Via oxidation type-specific modification of titin, UnDOx modulates human cardiomyocyte passive force bidirectionally. UnDOx also enhances titin phosphorylation and, importantly, promotes nonconstitutive folding and aggregation of unfolded domains. We propose a mechanism whereby UnDOx enables the controlled homotypic interactions within the distal titin spring to stabilize this segment and regulate myocardial passive stiffness.

Background Containment measures in the COVID-19 pandemic protected individuals at high risk, particularly individuals at old age, but little is known about how these measures affected health-related behavior of old aged individuals. We aimed to investigate the impact of the spring 2020 lockdown in Germany on healthcare-seeking and health-related lifestyle in the old aged and to identify susceptible subgroups. Methods We conducted a follow-up survey among the pre-pandemically well-characterized participants of our AugUR cohort study, residents in/around Regensburg aged 70+ years and relatively mobile. A self-completion questionnaire on current behavior, perceived changes, and SARS-Cov-2 infection was mailed in May 2020, shortly before contact restrictions ended. Pre-pandemic lifestyle and medical conditions were derived from previous study center visits. Results Among 1850 survey participants (73–98 years; net-response 89%), 74% were at increased risk for severe COVID-19 according to medical conditions; four participants reported SARS-CoV-2 infection (0.2%). Participants reported changes in behavior: 29% refrained from medical appointments, 14% increased TV consumption, 26% reported less physical activity, but no systematic increase of smoking or alcohol consumption. When comparing during- and pre-lockdown reports of lifestyle within participant, we found the same pattern as for the reported perceived changes. Women and the more educated were more susceptible to changes. Worse QOL was perceived by 38%. Conclusions Our data suggest that the spring 2020 lockdown did not affect the lifestyle of a majority of the mobile old aged individuals, but the substantial proportions with decreased physical activity and healthcare-seeking are markers of collateral damage.

B-type natriuretic peptide (BNP) and N-terminal proBNP (NT-proBNP) predict cardiovascular endpoints in patients and all-cause death in the general population. This was assigned to their association with clinical cardiac remodelling defined as changes in size, shape and function of the heart. The aim of this study was to evaluate whether NT-proBNP and BNP were associated with cardiovascular and overall death independent of clinical cardiac remodelling measured by echocardiography as left ventricular hypertrophy (LVH), diastolic dysfunction and left ventricular ejection fraction (EF). In a general population-based cohort study from Germany (KORA-S3) with subjects' baseline age ranging from 25 to 74 years, cardiac morphology and function were assessed as left ventricular mass (LVM), diastolic dysfunction and EF by echocardiography and circulating NT-proBNP and BNP were measured at baseline. In 1,223 subjects with mortality follow-up information, we examined the association of baseline NT-proBNP and BNP with cardiovascular mortality (number of deaths = 52, median follow-up time = 12.9years) using Cox regression without and with adjustment for cardiovascular risk factors, LVM, diastolic dysfunction and EF. The risk of cardiovascular mortality increased with higher NT-proBNP levels measured at baseline (hazard ratio HR = 1.67 per unit increment in logNT-proBNP, p = 2.78*10-4, adjusted for age and sex). This increased risk persisted after adjustment for cardiovascular risk factors, LVM, diastolic dysfunction and EF (HR = 1.73; p = 0.047). When excluding subjects with relevant LVH (LVM to body surface area > 149g/m2 in men / 122g/m2 in women), the NT-proBNP association with mortality was still significant (n = 1,138; number of deaths = 35; HR = 1.48; p = 0.04). We found similar results for BNP. Our data confirms NT-proBNP and BNP as predictor of cardiovascular mortality in a large general population-based study with long-term follow-up. Our study extends previously published population-based studies to younger and potentially healthier individuals without relevant LVH, diastolic dysfunction or LVD.

Heart failure induced cachexia is highly prevalent. Insights into disease progression are lacking. Early state of left ventricular dysfunction (ELVD) and symptomatic systolic heart failure (HF) were both induced in rabbits by tachypacing. Tissue of limb muscle (LM) was subjected to histologic assessment. For unbiased characterisation of early and late myopathy, a proteomic approach followed by computational pathway-analyses was performed and combined with pathway-focused gene expression analyses. Specimen of thoracic diaphragm (TD) served as control for inactivity-induced skeletal muscle alterations. In a subsequent study, inhibition of the renin-angiotensin-system and neprilysin (RAS-/NEP) was compared to placebo. HF was accompanied by loss of protein content (8.7±0.4% vs. 7.0±0.5%, mean±SEM, control vs. HF, p<0.01) and a slow-to-fast fibre type switch, establishing hallmarks of cachexia. In ELVD, the enzymatic set-up of LM and TD shifted to a catabolic state. A disturbed malate-aspartate shuttle went well with increased enzymes of glycolysis, forming the enzymatic basis for enforced anoxic energy regeneration. The histological findings and the pathway analysis of metabolic results drew the picture of suppressed PGC-1α signalling, linked to the natriuretic peptide system. In HF, natriuretic peptide signalling was desensitised, as confirmed by an increase in the ratio of serum BNP to tissue cGMP (57.0±18.6pg/ml/nM/ml vs. 165.8±16.76pg/ml/nM/ml, p<0.05) and a reduced expression of natriuretic peptide receptor-A. In HF, combined RAS-/NEP-inhibition prevented from loss in protein content (8.7±0.3% vs. 6.0±0.6% vs. 8.3±0.9%, Baseline vs. HF-Placebo vs. HF-RAS/NEP, p<0.05 Baseline vs. HF-Placebo, p = 0.7 Baseline vs. HF-RAS/NEP). Tachypacing-induced heart failure entails a generalised myopathy, preceding systolic dysfunction. The characterisation of \"pre-cachectic\" state and its progression is feasible. Early enzymatic alterations of LM depict a catabolic state, rendering LM prone to futile substrate metabolism. A combined RAS-/NEP-inhibition ameliorates cardiac-induced myopathy independent of systolic function, which could be linked to stabilised natriuretic peptide/cGMP/PGC-1α signalling.

ObjectiveEuropean guidelines recommended a uniform upper reference limit of high-sensitivity cardiac troponin T (hsTnT) to rule out non-ST segment elevation myocardial infarction. Our study aimed to provide a hsTnT reference distribution and to assess the specificity of the 14 ng/L cut-off value in the mobile population ≥70 years of age.DesignA cross-sectional analysis was performed in the German AugUR study (Altersbezogene Untersuchungen zur Gesundheit der University of Regensburg).SettingStudy population was the mobile population aged 70+ years living in the city and county of Regensburg, Germany.ParticipantsA random sample was derived from the local population registries of residence. Of the 5644 individuals invited, 1133 participated (response ratio=20.1%). All participants came to the study centre and were mentally and physically mobile to conduct the protocol (face-to-face interview, blood draw and standardised transthoracic echocardiography). None of the participants was in an acute state of myocardial infarction.ResultsAmong the 1129 individuals with hsTnT measurements (overall median=10.0 ng/L(25th, 75th percentile)=(7.0, 15.0 ng/L)), hsTnT was higher among the older individuals and higher among men (men 70–74 years median=9.6 ng/L (7.2, 13.1 ng/L); men 90–95 years median=21.2 ng/L (14.6, 26.0 ng/L); women 70–74 years median=6.3 ng/L (4.7, 8.7 ng/L); and women 90–95 years median=18.0 ng/L (11.0, 21.0 ng/L)). In participants with impaired kidney function (eGFRcrea <60 mL/min/1.73 m2), hsTnT was elevated (median=13.6 ng/L (9.4, 20.6 ng/L)).Specificity of recommended upper reference limit, 14 ng/L, is 68%. Most false positives were among men aged >79 years (specificity=34%). In a healthy subgroup (n=96, none of the following: overt heart disease, impaired renal function, blood pressure >160/100 mm Hg, left ventricular hypertrophy and diastolic/systolic dysfunction), specificity was 90%.ConclusionIn the elderly population without acute myocardial infarction, hsTnT further increases with age showing different levels for men and women. The specificity of the 14 ng/L cut-off is considerably lower than 99%, even in healthy subjects.

Our study aimed to evaluate epicardial adipose tissue (EAT) thickness in old adults, identify potential factors influencing it, and explore the association between EAT and left ventricular hypertrophy (LVH) in the older adult population. We analyzed cross-sectional data from the population-based AugUR study, including subjects aged ≥70 years. Cardiac geometry and EAT thickness were measured by echocardiography. Among 988 participants aged 70-95 years (55.8% men), LVH was present in 368 individuals (37.2%). EAT thickness was similar between women and men (mean ± standard deviation: 4.1 ± 2.0 mm vs. 4.2 ± 1.9 mm,  = 0.29) but increased with age group (70-79 years: 4.0 ± 1.8 mm, >79 years 4.5 ± 2.0 mm,  < 0.001). Linear regression models of potential risk factors influencing EAT thickness showed associations with age [  = 0.038 mm per year; 95% confidence interval (CI) = 0.014-0.063,  < 0.05], body mass index (BMI) (  = 0.097 mm per kg/m , 95% CI = 0.070-0.124,  < 0.05), and low-density lipoprotein-cholesterol (LDL,  = 0.008 mm per mg/dL, 95% CI = 0.004-0.012,  < 0.05). Given the reported causal relationship between EAT and LVH in experimental studies, multivariable regression models were performed to evaluate the association between EAT thickness and left ventricular mass index (LVMi). EAT thickness was associated with LVMi independent of sex, age, BMI, LDL, smoking, hypertension, diabetes, and chronic kidney disease (LVMi  = 2.43 g/m /mm, 95% CI 1.26-3.59,  = <0.001; LVH OR = 1.36/mm, 95% CI 1.01-1.84,  < 0.05). This association was strong in men but not in women. EAT thickness continues to increase with age beyond 69 years. Age, BMI, and LDL-cholesterol are associated with increasing EAT thickness. Our study strengthens the experimental hypothesis of a link between EAT and LVH by translational, population-based data. However, this association is more pronounced in men than in women.

Background Percutaneous mitral valve repair (PMVR) is increasingly performed in patients with severe mitral regurgitation (MR). Post-procedural MR grading is challenging and an unsettled issue. We hypothesised that the direct planimetry of vena contracta area (VCA) by 3D–transoesophageal echocardiography allows quantifying post-procedural MR and implies further prognostic relevance missed by the usual ordinal scale (grade I-IV). Methods Based on a single-centre PMVR registry containing 102 patients, the association of VCA reduction and patients’ functional capacity measured as six-minute walk distance (6 MW) was evaluated. 3D–colour-Doppler datasets were available before, during and 4 weeks after PMVR. Results Twenty nine patients (age 77.0 ± 5.8 years) with advanced heart failure (75.9% NYHA III/IV) and severe degenerative (34%) or functional (66%) MR were eligible. VCA was reduced in all patients by PMVR (0.99 ± 0.46 cm 2 vs. 0.22 ± 0.15 cm 2 , p  < 0.0001). It remained stable after median time of 33 days ( p  = 0.999). 6 MW improved after the procedure (257.5 ± 82.5 m vs. 295.7 ± 96.3 m, p  < 0.01). Patients with a decrease in VCA less than the median VCA reduction showed a more distinct improvement in 6 MW than patients with better technical result ( p  < 0.05). This paradoxical finding was driven by inferior results in very large functional MR. Conclusions VCA improves the evaluation of small residual MR. Its post-procedural values remain stable during a short-term follow-up and imply prognostic information for the patients’ physical improvement. VCA might contribute to a more substantiated estimation of treatment success in the heterogeneous functional MR group.

Inhibitors of the renin angiotensin system and neprilysin (RAS-/NEP-inhibitors) proved to be extraordinarily beneficial in systolic heart failure. Furthermore, compelling evidence exists that impaired mitochondrial pathways are causatively involved in progressive left ventricular (LV) dysfunction. Consequently, we aimed to assess whether RAS-/NEP-inhibition can attenuate mitochondrial adaptations in experimental heart failure (HF). By progressive right ventricular pacing, distinct HF stages were induced in 15 rabbits, and 6 animals served as controls (CTRL). Six animals with manifest HF (CHF) were treated with the RAS-/NEP-inhibitor omapatrilat. Echocardiographic studies and invasive blood pressure measurements were undertaken during HF progression. Mitochondria were isolated from LV tissue, respectively, and further worked up for proteomic analysis using the SWATH technique. Enzymatic activities of citrate synthase and the electron transfer chain (ETC) complexes I, II, and IV were assessed. Ultrastructural analyses were performed by transmission electron microscopy. During progression to overt HF, intricate expression changes were mainly detected for proteins belonging to the tricarboxylic acid cycle, glucose and fat metabolism, and the ETC complexes, even though ETC complex I, II, or IV enzymatic activities were not significantly influenced. Treatment with a RAS-/NEP-inhibitor then reversed some maladaptive metabolic adaptations, positively influenced the decline of citrate synthase activity, and altered the composition of each respiratory chain complex, even though this was again not accompanied by altered ETC complex enzymatic activities. Finally, ultrastructural evidence pointed to a reduction of autophagolytic and degenerative processes with omapatrilat-treatment. This study describes complex adaptations of the mitochondrial proteome in experimental tachycardia-induced heart failure and shows that a combined RAS-/NEP-inhibition can beneficially influence mitochondrial key pathways.

Implantation of left ventricular assist devices (LVADs) as bridge to transplant in end-stage heart failure allows for analyzing reverse remodeling processes of the supported heart. Whether this therapy influences the cGMP–PKG signaling pathway, which is currently under thorough investigation for developing new heart failure therapeutics, is unknown. In fourteen end-stage heart failure patients (8 with dilated cardiomyopathy, DCM; 6 with ischemic cardiomyopathy, ICM) tissue specimens of left ventricles were collected at LVAD implantation and afterwards at receiver heart explantation, respectively. Then the expressions of key components of the cGMP–PKG signaling pathway were determined by polymerase chain reaction (ANP; BNP; natriuretic peptide receptor A, NPR-A; natriuretic peptide receptor C, NPR-C; neprilysin; NOS3; soluble guanylyl cyclase, sGC; PDE5; cGMP-dependent protein kinase G, PKG) and enzyme-linked immunosorbent assay (cGMP), respectively. Patients were predominantly male, 52 ± 10 years old, were receiving recommended heart failure therapy, and had their donor organ implanted after 351 ± 317 days of LVAD support. Except for more DCM patients with ICD therapy, no significant differences were detected between ICM and DCM, which also applies to the expression of cGMP–PKG pathway components at baseline. After LVAD support, ANP, NPR-C, and cGMP were significantly down-regulated and neprilysin, PDE5, and PKG I expressions were reduced with borderline significance in DCM, but not in ICM patients. Multiple significant correlations were found for expression differences (i.e., expression at LVAD implantation minus expression at heart transplantation) both in DCM and ICM, even though there was a closer connection between the NO and NP side of the cGMP–PKG pathway in DCM patients. Furthermore, duration of LVAD support negatively correlated with expression differences of PKG I, PDE5, and sGC in ICM, but not in DCM. Originating from the same activation level at LVAD implantation, cardiac unloading significantly alters key components of the cGMP–PKG pathway in DCM, but not in ICM patients. This etiology-specific regulation should be considered when analyzing therapeutic interventions with effects on this signaling pathway.

Purpose of Review In highly prevalent cardiac diseases, new therapeutic approaches are needed. Since the first description of oxidative stress in heart failure, reactive oxygen species (ROS) have been considered as attractive drug targets. Though clinical trials evaluating antioxidant vitamins as ROS-scavenging agents yielded neutral results in patients at cardiovascular risk, the knowledge of ROS as pathophysiological factors has considerably advanced in the past few years and led to novel treatment approaches. Here, we review recent new insights and current strategies in targeting mitochondrial calcium handling and ROS in heart failure. Recent Findings Mitochondria are an important ROS source, and more recently, drug development focused on targeting mitochondria (e.g. by SS-31 or MitoQ). Important advancement has also been made to decipher how the matching of energy supply and demand through calcium (Ca 2+ ) handling impacts on mitochondrial ROS production and elimination. This opens novel opportunities to ameliorate mitochondrial dysfunction in heart failure by targeting cytosolic and mitochondrial ion transporters to improve this matching process. According to this approach, highly specific substances as the preclinical CGP-37157, as well as the clinically used ranolazine and empagliflozin, provide promising results on different levels of evidence. Furthermore, the understanding of redox signalling relays, resembled by catalyst-mediated protein oxidation, is about to change former paradigms of ROS signalling. Novel methods, as redox proteomics, allow to precisely analyse key regulatory thiol switches, which may induce adaptive or maladaptive signalling. Additionally, the generation of genetically encoded probes increased the spatial and temporal resolution of ROS imaging and opened a new methodological window to subtle, formerly obscured processes. Summary These novel insights may broaden our understanding of why previous attempts to target oxidative stress have failed, and at the same time provide us with new targets for drug development.