[Updated guidelines for cardiac patients with diabetes - Pragmatic diagnostic and therapeutic algorithm]

Individuals with type 2 diabetes are subjected to a disproportionately increased risk for development and progression of cardiovascular disease. Positive outcomes of recent clinical trials have led to the introduction of seminal novel therapeutic options for patients with type 2 diabetes and accompanying cardiovascular risk factors and disease. Consequently, the European Society of Cardiology published an update of the existing guideline for the management of these patients. The aim of this article is to provide a simplified and pragmatic algorithm for diagnostics and treatment for the vast majority of patients with type 2 diabetes, based on current guideline recommendations.

The Prognostic Value of Right Ventricular Function in Patients with Chronic Heart Failure-A Prospective Study

Background: In patients with stable chronic heart failure with a reduced ejection fraction (HFrEF), left ventricular ejection fraction (LVEF) provides limited prognostic value, especially in patients with moderately to severely reduced LVEF. Echocardiographic parameters of right ventricular function may be associated with adverse clinical events in these patients. Therefore, we analyzed 164 patients with HFrEF in a prospective single-center cohort study to evaluate whether the parameters of right ventricular function are associated with worsening heart failure (WHF) hospitalizations, cardiovascular and all-cause deaths and combined endpoints. Methods: Echocardiographic cine loops were analyzed using vendor-independent post-processing software. Multivariate Cox regression analyses were performed, which were then adjusted for clinical characteristics and left ventricular functional parameters. Results: In these models, higher tricuspid annular plane systolic excursion (TAPSE) was significantly associated with lower rates of WHF hospitalizations (HR 0.880, 95%CI 0.800-0.968, p = 0.008), a composite endpoint of WHF hospitalizations and cardiovascular death (HR 0.878, 95%CI 0.800-0.964, p = 0.006), and a composite endpoint of WHF hospitalization and all-cause death (HR 0.918, 95%CI 0.853-0.988, p = 0.023). These associations were more pronounced in patients with LVEF ≤ 35%. Conclusions: In conclusion, in patients with HFrEF, TAPSE is an independent prognosticator for adverse clinical outcomes, warranting further studies to elucidate whether incorporating TAPSE into established risk scores improves their diagnostic accuracy.

Low-grade systemic inflammation and left ventricular dysfunction in hypertensive compared to non-hypertensive hypertrophic cardiomyopathy

BACKGROUND

Arterial hypertension (HTN) is associated with excess mortality in hypertrophic cardiomyopathy (HCM), but underlying mechanisms are largely elusive. The objective of this study was to investigate the association between HTN and markers of left ventricular (LV) dysfunction and low-grade systemic inflammation in a HCM cohort.

METHODS

This was a single-center cross-sectional case-control study comparing echocardiographic and plasma-derived indices of LV dysfunction and low-grade systemic inflammation between 30 adult patients with HCM and HTN (HTN+) and 30 sex- and age-matched HCM patients without HTN (HTN-). Echocardiographic measures were assessed using post-processing analyses by blinded investigators.

RESULTS

Mean age of the study population was 55.1 ± 10.4 years, 30% were women. Echocardiographic measures of systolic and diastolic dysfunction, including speckle-tracking derived parameters, did not differ between HTN+ and HTN-. Moreover, levels of N-terminal pro B-type natriuretic peptide were balanced between cases and controls. Compared with HTN-, HTN+ patients exhibited a higher white blood cell count [8.1 ± 1.8 109/l vs. 6.4 ± 1.6 109/l; p < 0.001] as well as higher plasma levels of interleukin-6 [2.8 pg/ml (2.0, 5.4) vs. 2.1 pg/ml (1.5, 3.4); p = 0.008] and high-sensitivity C-reactive protein [2.6 mg/l (1.4, 6.5) vs. 1.1 mg/l (0.9, 2.4); p = 0.004].

CONCLUSION

This study demonstrates that HTN is associated with indices of low-grade systemic inflammation among HCM patients. Moreover, this analysis indicates that the adverse impact of HTN in HCM patients is a consequence of systemic effects rather than alterations of cardiac function, as measures of LV systolic and diastolic dysfunction did not differ between HTN+ and HTN-.

Outcomes of ECLS-SHOCK Eligibility Criteria Applied to a Real-World Cohort

BACKGROUND

Cardiogenic shock (CS) exhibits high (~50%) in-hospital mortality. The recently published Extracorporeal life Support in Cardiogenic Shock (ECLS-SHOCK) trial demonstrated the neutral effects of the use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) on all-cause death, as well as on all secondary outcomes in subjects presenting with myocardial-infarction (MI)-related CS. Here, we compared ECLS-SHOCK eligibility criteria with a real-world cohort of CS patients.

METHODS AND RESULTS

ECLS-SHOCK eligibility criteria were applied to a prospective single-center CS registry (the PREPARE CS registry) consisting of 557 patients who were consecutively admitted to the catheterization laboratory (cath lab) of the Medical University of Graz, Austria, due to CS (SCAI C-E). Overall use of mechanical circulatory support (MCS) in this cohort was 19%. Sixty-nine percent of the entire cohort had MI-related CS, 38% of whom would have met ECLS-SHOCK eligibility criteria, thus representing only 27% of the PREPARE CS registry. Exclusion from the ECLS-SHOCK trial was based on patients with initial lactate values below 3 mmol/L (n = 168; 43.6%), aged over 80 years (n = 65; 16.9%), and with a duration of cardiopulmonary resuscitation (CPR) exceeding 45 min (n = 22; 5.7%). The 30-day mortality of patients of the PREPARE CS registry who met the ECLS-SHOCK eligibility criteria was 57.0%, compared to 48.4% of patients in the ECLS-SHOCK trial. The patients' baseline characteristics, however, differed considerably with respect to type of infarction, age, and gender.

CONCLUSIONS

In a real-world cohort of patients with MI-related CS, only 38% of patients met the eligibility criteria of the ECLS-SHOCK trial. Thus, the impact of the use of VA-ECMO on outcome parameters in MI-related CS, as observed in the ECLS-SHOCK trial, may differ in a more heterogeneous real-world CS population of the PREPARE CS registry.

Transcriptomic and proteomic profiling of human diabetic heart disease

 

Studies in animal models demonstrated the capability of type 2 diabetes (T2D) to induce cardiac dysfunction in the absence of vascular disease. However, whether and how T2D also impairs structure and function in human hearts remains poorly understood. Here, we performed transcriptional and proteomic profiling of left ventricular samples of 8 subjects with T2D, preserved EF (63,5%) and no history of ischemic heart disease (= diabetic cardiomyopathy; DbCM), 7 subjects with T2D, reduced EF (26,9%) and ischemic heart disease (= diabetic heart failure; DbHF), and 15 non-diabetic individuals with normal EF (64,7%) serving as controls. Among 1168 proteins identified by LC-MS/MS, 146 proteins were differentially regulated in DbHF, but only 66 in DbCM. Pathway analysis revealed downregulation of energy metabolic proteins, but upregulation of proteins involved in oxidative stress and inflammatory response. In DbCM, pathways of structural remodeling, cardiomyocyte proliferation, and mechanotransduction were upregulated. Bulk RNA sequencing revealed 1795 differentially regulated genes in DbHF, and 527 in DbCM, with only 128 genes being commonly regulated. DbHF, but not DbCM, could be clearly discriminated from controls by hierarchical clustering. While inflammation/immunity were major regulated pathways in DbHF, extracellular matrix remodeling and cellular growth were the most regulated pathways in DbCM. Thus, the differential regulation of biological pathways in DbCM versus DbHF suggests the existence of two distinct disease entities rather than DbHF being an advanced disease stage of DbCM.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Austrian Diabetes Society

Myocardial infarction with non-obstructive coronary arteries in a patient double-seropositive for anti-glomerular basement membrane and anti-neutrophil cytoplasmic antibodies: A case report

We report a case of a patient double-seropositive for anti-glomerular basement membrane (anti-GBM) and anti-neutrophil cytoplasmic antibodies (ANCA) who reported retrosternal chest pain during a regular hemodialysis session associated with ST-segment depression in electrocardiogram and an increase of serum high-sensitivity troponin T. Urgent coronary angiography excluded obstructive coronary artery disease, suggesting the diagnosis of ischemia with non-obstructive coronary arteries. This case illustrates an unusual presentation of cardiovascular involvement in a patient with double-positive ANCA/anti-GBM disease, emphasizing the possible relevance of coronary microvascular dysfunction and the need for close cardiovascular follow-up in this patient population.

Effects of Short Term Adiponectin Receptor Agonism on Cardiac Function and Energetics in Diabetic db/db Mice

Objective

Impaired cardiac efficiency is a hallmark of diabetic cardiomyopathy in models of type 2 diabetes. Adiponectin receptor 1 (AdipoR1) deficiency impairs cardiac efficiency in non-diabetic mice, suggesting that hypoadiponectinemia in type 2 diabetes may contribute to impaired cardiac efficiency due to compromised AdipoR1 signaling. Thus, we investigated whether targeting cardiac adiponectin receptors may improve cardiac function and energetics, and attenuate diabetic cardiomyopathy in type 2 diabetic mice.

Methods

A non-selective adiponectin receptor agonist, AdipoRon, and vehicle were injected intraperitoneally into Eight-week-old db/db or C57BLKS/J mice for 10 days. Cardiac morphology and function were evaluated by echocardiography and working heart perfusions.

Results

Based on echocardiography, AdipoRon treatment did not alter ejection fraction, left ventricular diameters or left ventricular wall thickness in db/db mice compared to vehicle-treated mice. In isolated working hearts, an impairment in cardiac output and efficiency in db/db mice was not improved by AdipoRon. Mitochondrial respiratory capacity, respiration in the presence of oligomycin, and 4-hydroxynonenal levels were similar among all groups. However, AdipoRon induced a marked shift in the substrate oxidation pattern in db/db mice towards increased reliance on glucose utilization. In parallel, the diabetes-associated increase in serum triglyceride levels in vehicle-treated db/db mice was blunted by AdipoRon treatment, while an increase in myocardial triglycerides in vehicle-treated db/db mice was not altered by AdipoRon treatment.

Conclusion

AdipoRon treatment shifts myocardial substrate preference towards increased glucose utilization, likely by decreasing fatty acid delivery to the heart, but was not sufficient to improve cardiac output and efficiency in db/db mice.

Mass Spectrometry-Based Redox and Protein Profiling of Failing Human Hearts

Oxidative stress contributes to detrimental functional decline of the myocardium, leading to the impairment of the antioxidative defense, dysregulation of redox signaling, and protein damage. In order to precisely dissect the changes of the myocardial redox state correlated with oxidative stress and heart failure, we subjected left-ventricular tissue specimens collected from control or failing human hearts to comprehensive mass spectrometry-based redox and quantitative proteomics, as well as glutathione status analyses. As a result, we report that failing hearts have lower glutathione to glutathione disulfide ratios and increased oxidation of a number of different proteins, including constituents of the contractile machinery as well as glycolytic enzymes. Furthermore, quantitative proteomics of failing hearts revealed a higher abundance of proteins responsible for extracellular matrix remodeling and reduced abundance of several ion transporters, corroborating contractile impairment. Similar effects were recapitulated by an in vitro cell culture model under a controlled oxygen atmosphere. Together, this study provides to our knowledge the most comprehensive report integrating analyses of protein abundance and global and peptide-level redox state in end-stage failing human hearts as well as oxygen-dependent redox and global proteome profiles of cultured human cardiomyocytes.

Sirtuin 4 contributes to heart failure development by increasing mitochondrial oxidative stress

 

Sirtuin 4 (SIRT4) is a mitochondrial NAD+-dependent deacylase which inhibits the oxidation of glucose and fatty acids, and has been implicated in the regulation of oxidative stress. Given the importance of cardiac energy depletion and ROS during heart failure development, we aimed to define the role of SIRT4 in the development of heart failure. Mice with deletion (SIRT4−/−) or overexpression (SIRT4 TG) of SIRT4 were subjected to transverse aortic constriction (TAC) for 12 weeks or underwent sham procedures. Using echocardiography, ejection fraction (EF) was not different between SIRT4 TG and WT mice subjected to sham operations. In contrast, TAC induced a more pronounced decrease in EF (35% vs. 51%; p&lt;0.05), and a more pronounced increase in LV endsystolic diameter (4.5mm vs. 3.6mm; p&lt;0.05) and myocardial fibrosis (2.2-fold; p&lt;0.05) in SIRT4 TG mice compared to WT mice. Myocardial levels of the lipid peroxidation product 4-hydroxynonenal were increased in WT mice following TAC and were synergistically increased in SIRT4 TG mice following TAC (+66% vs. WT TAC; p&lt;0.05). Administration of the mitochondria-targeted antioxidant MitoQ normalized 4-hydroxynonenal levels, markedly attenuated the decline in EF and almost normalized endsystolic LV diameter in SIRT4 TG mice following TAC. Cardiac function and morphology were unaffected in SIRT4−/− mice during normal or increased workload conditions. Thus, while SIRT4 is not required to maintain cardiac function even in response to increased energy demands, increased expression of SIRT4 accelerates the development of heart failure following TAC, at least in part due to increased mitochondrial oxidative stress.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): German Research Foundation

Complications and mortality of cardiovascular emergency admissions during COVID-19 associated restrictive measures

While hospital admissions for myocardial infarction (MI) and pulmonary embolism (PE) are decreased during the COVID-19 pandemic, controversy remains about respective complication and mortality rates. This study evaluated admission rates, complications, and intrahospital mortality for selected life-threatening cardiovascular emergencies (MI, PE, and acute aortic dissection (AAD)) during COVID-19-associated restrictive social measures (RM) in Styria, Austria. By screening a patient information system for International Statistical Classification of Diseases and Related Health Problems (ICD) diagnosis codes covering more than 85% of acute hospital admissions in the state of Styria (~1.24 million inhabitants), we retrospectively identified patients with admission diagnoses for MI (I21, I22), PE (I26), and AAD (I71). Rates of complications such as cardiogenic shock and cardiopulmonary resuscitation, treatment escalations (thrombolysis for PE), and mortality were analyzed by patient chart review during 6 weeks following onset of COVID-19 associated RM, and during respective time frames in the years 2016 to 2019. 1,668 patients were included. Cumulative admissions for MI, PE and AAD decreased (RR 0.77; p<0.001) during RM compared to previous years. In contrast, intrahospital mortality increased by 65% (RR 1.65; p = 0.041), mainly driven by mortality following MI (RR 1.80; p = 0.042). PE patients received more frequently thrombolysis treatment (RR 3.63; p = 0.006), while rates of cardiogenic shock and cardiopulmonary resuscitation remained unchanged. Of 226 patients hospitalized during RM, 81 patients with suspected COVID-19 disease were screened for SARS-CoV-2 infection with only 5 testing positive. Thus, cumulative hospital admissions for cardiovascular emergencies decreased during COVID-19 associated RM while intrahospital mortality increased.

Mitochondrial Mechanisms in Diabetic Cardiomyopathy

Mitochondrial medicine is increasingly discussed as a promising therapeutic approach, given that mitochondrial defects are thought to contribute to many prevalent diseases and their complications. In individuals with diabetes mellitus (DM), defects in mitochondrial structure and function occur in many organs throughout the body, contributing both to the pathogenesis of DM and complications of DM. Diabetic cardiomyopathy (DbCM) is increasingly recognized as an underlying cause of increased heart failure in DM, and several mitochondrial mechanisms have been proposed to contribute to the development of DbCM. Well established mechanisms include myocardial energy depletion due to impaired adenosine triphosphate (ATP) synthesis and mitochondrial uncoupling, and increased mitochondrial oxidative stress. A variety of upstream mechanisms of impaired ATP regeneration and increased mitochondrial reactive oxygen species have been proposed, and recent studies now also suggest alterations in mitochondrial dynamics and autophagy, impaired mitochondrial Ca²⁺ uptake, decreased cardiac adiponectin action, increased O-GlcNAcylation, and impaired activity of sirtuins to contribute to mitochondrial defects in DbCM, among others. In the current review, we present and discuss the evidence that underlies both established and recently proposed mechanisms that are thought to contribute to mitochondrial dysfunction in DbCM.

P3480Tissue-specific regulation of the mitochondrial proteome by adiponectin receptor 1

Lack of the adiponectin target receptor adiponectin receptor 1 (AdipoR1) impairs gene expression of mitochondrial OXPHOS proteins due to impaired AMPK-SIRT1-PGC-1α signaling. Since decreased adiponectin serum levels in diabetes mellitus should thus compromise AdipoR1 signaling, we hypothesized that impaired AdipoR1 signaling may causally contribute to typically observed mitochondrial defects in diabetes complications. Thus, we performed comparative proteomics in cardiac, renal and hepatic tissue of AdipoR1−/− mice using LC-MS/MS. Using principal component analysis, heatmapping and hierarchical clustering, a significant separation of genotypes was observed across tissues. Enrichment analysis of differentially expressed proteins revealed disproportionate representation of proteins involved in oxidative phosphorylation, TCA cycle and fatty acid oxidation in all tissues. While 121 or 98 or 78 proteins were differentially regulated in cardiac or renal or hepatic tissue, respectively, only 15 proteins were regulated in the same direction across all tissues. Pathway analysis identified HNF4, NRF1, LONP, RICTOR, SURF1, insulin receptor and PGC-1α as most likely upstream regulators. Importantly, we found a dramatic downregulation of AdipoR1 expression in heart (−70%), liver (−90%) and kidney (−80%; all p<0.05) of high fat-fed and prediabetic non-transgenic mice compared to low fat-fed mice. In addition and beyond diabetes, AdipoR1 expression was also decreased in endstage failing hearts of non-diabetic human subjects compared to non-failing donor hearts. Thus, we conclude that AdipoR1 signaling regulates mitochondrial protein composition across all tissues in a functionally conserved, yet molecularly distinct, manner. Impaired AdipoR1 signaling may causally contribute to mitochondrial defects in diabetic complications and even human heart failure.

Established and Emerging Mechanisms of Diabetic Cardiomyopathy

Diabetes mellitus increases the risk for the development of heart failure even in the absence of coronary artery disease and hypertension, a cardiac entity termed diabetic cardiomyopathy (DC). Clinically, DC is increasingly recognized and typically characterized by concentric cardiac hypertrophy and diastolic dysfunction, ultimately resulting in heart failure with preserved ejection fraction (HFpEF) and potentially even heart failure with reduced ejection fraction (HFrEF). Numerous molecular mechanisms have been proposed to underlie the alterations in myocardial structure and function in DC, many of which show similar alterations in the failing heart. Well investigated and established mechanisms of DC include increased myocardial fibrosis, enhanced apoptosis, oxidative stress, impaired intracellular calcium handling, substrate metabolic alterations, and inflammation, among others. In addition, a number of novel mechanisms that receive increasing attention have been identified in recent years, including autophagy, dysregulation of microRNAs, epigenetic mechanisms, and alterations in mitochondrial protein acetylation, dynamics and quality control. This review aims to provide an overview and update of established underlying mechanisms of DC, as well as a discussion of recently identified and emerging mechanisms that may also contribute to the structural and functional alterations in DC.

Dysregulation of the Mitochondrial Proteome Occurs in Mice Lacking Adiponectin Receptor 1

Decreased serum adiponectin levels in type 2 diabetes has been linked to the onset of mitochondrial dysfunction in diabetic complications by impairing AMPK-SIRT1-PGC-1α signaling via impaired adiponectin receptor 1 (AdipoR1) signaling. Here, we aimed to characterize the previously undefined role of disrupted AdipoR1 signaling on the mitochondrial protein composition of cardiac, renal, and hepatic tissues as three organs principally associated with diabetic complications. Comparative proteomics were performed in mitochondria isolated from the heart, kidneys and liver of Adipor1 ^-/- mice. A total of 790, 1,573, and 1,833 proteins were identified in cardiac, renal and hepatic mitochondria, respectively. While 121, 98, and 78 proteins were differentially regulated in cardiac, renal, and hepatic tissue of Adipor1^-/- mice, respectively; only 15 proteins were regulated in the same direction across all investigated tissues. Enrichment analysis of differentially expressed proteins revealed disproportionate representation of proteins involved in oxidative phosphorylation conserved across tissue types. Curated pathway analysis identified HNF4, NRF1, LONP, RICTOR, SURF1, insulin receptor, and PGC-1α as candidate upstream regulators. In high fat-fed non-transgenic mice with obesity and insulin resistance, AdipoR1 gene expression was markedly reduced in heart (-70%), kidney (-80%), and liver (-90%) (all P < 0.05) as compared to low fat-fed mice. NRF1 was the only upstream regulator downregulated both in Adipor1^-/- mice and in high fat-fed mice, suggesting common mechanisms of regulation. Thus, AdipoR1 signaling regulates mitochondrial protein composition across all investigated tissues in a functionally conserved, yet molecularly distinct, manner. The biological significance and potential implications of impaired AdipoR1 signaling are discussed.