IGF-1 boosts mitochondrial function by a Ca2+ uptake-dependent mechanism in cultured human and rat cardiomyocytes

A physiological increase in cardiac workload results in adaptive cardiac remodeling, characterized by increased oxidative metabolism and improvements in cardiac performance. Insulin-like growth factor-1 (IGF-1) has been identified as a critical regulator of physiological cardiac growth, but its precise role in cardiometabolic adaptations to physiological stress remains unresolved. Mitochondrial calcium (Ca²⁺) handling has been proposed to be required for sustaining key mitochondrial dehydrogenase activity and energy production during increased workload conditions, thus ensuring the adaptive cardiac response. We hypothesized that IGF-1 enhances mitochondrial energy production through a Ca²⁺-dependent mechanism to ensure adaptive cardiomyocyte growth. We found that stimulation with IGF-1 resulted in increased mitochondrial Ca²⁺ uptake in neonatal rat ventricular myocytes and human embryonic stem cell-derived cardiomyocytes, estimated by fluorescence microscopy and indirectly by a reduction in the pyruvate dehydrogenase phosphorylation. We showed that IGF-1 modulated the expression of mitochondrial Ca²⁺ uniporter (MCU) complex subunits and increased the mitochondrial membrane potential; consistent with higher MCU-mediated Ca²⁺ transport. Finally, we showed that IGF-1 improved mitochondrial respiration through a mechanism dependent on MCU-mediated Ca²⁺ transport. In conclusion, IGF-1-induced mitochondrial Ca²⁺ uptake is required to boost oxidative metabolism during cardiomyocyte adaptive growth.

Evaluation and management of cancer patients presenting with acute cardiovascular disease: a Clinical Consensus Statement of the Acute CardioVascular Care Association (ACVC) and the ESC council of Cardio-Oncology—part 2: acute heart failure, acute myocardial diseases, acute venous thromboembolic diseases, and acute arrhythmias

Advances in treatment, common cardiovascular (CV) risk factors and the ageing of the population have led to an increasing number of cancer patients presenting with acute CV diseases. These events may be related to cancer itself or cancer treatment. Acute cardiac care specialists must be aware of these acute CV complications and be able to manage them. This may require an individualized and multidisciplinary approach. The management of acute coronary syndromes and acute pericardial diseases in cancer patients was covered in part 1 of a clinical consensus document. This second part focusses on acute heart failure, acute myocardial diseases, venous thromboembolic diseases and acute arrhythmias.

An Erythropoietin-Independent Mechanism of Erythrocytic Precursor Proliferation Underlies Hypoxia Tolerance in Sea Nomads

The Bajau Sea Nomads were recently demonstrated to have evolved larger spleens as an adaptation to millennia of a marine foraging lifestyle. The large-spleen phenotype appears to derive from increases in thyroid hormone (TH) production as a result of reduced expression of phosphodiesterase 10A (PDE10A), though the exact mechanism remains unknown. Through pharmacological inhibition of PDE10A using the selective inhibitor MP-10 in mice, we were able to mimic the Bajau adaptation and show that treated mice had significantly larger spleens than control animals. This difference appears connected to an excess of early stage erythrocytes and an apparent increase in red blood cell (RBC) precursor proliferation in response to increased TH. However, we determined that the stimulation of RBC production in the mouse model via TH is Erythropoietin (EPO)-independent, unlike in the altitude (chronic hypoxemia) response. We confirmed this using human GWAS data; although the Bajau PDE10A variants are significantly associated with increased TH levels and RBC count, they are not associated with EPO levels, nor are other strongly thyroid-associated SNPs. We therefore suggest that an EPO-independent mechanism of stimulating RBC precursor proliferation via TH upregulation underlies the increase in spleen size observed in Sea Nomad populations.

Patiromer for the management of hyperkalaemia in patients receiving renin-angiotensin-aldosterone system inhibitors for heart failure: design and rationale of the DIAMOND trial

AIMS

In patients with current or a history of hyperkalaemia, treatment with renin-angiotensin-aldosterone system inhibitors (RAASi) is often compromised. Patiromer, a novel potassium (K⁺ ) binder, may improve serum K⁺ levels and adherence to RAASi.

METHODS

The DIAMOND trial will enroll ∼820 patients with heart failure with reduced ejection fraction (HFrEF; ejection fraction ≤40%). Patients meeting the screening criteria will enter a single-blinded run-in phase where they will be started or continued on a mineralocorticoid receptor antagonist (MRA) titrated to 50 mg/day and other RAASi therapy to ≥50% target dose, and patiromer. Patiromer will be titrated up to a maximum three packs/day (8.4 g/pack) to achieve optimal doses of RAASi without hyperkalaemia. The run-in phase will last up to 12 weeks, following which patients will undergo double-blind randomization in a 1:1 ratio to receive either continued patiromer or placebo (patiromer withdrawal). The primary endpoint is the mean difference in serum K⁺ from randomization between patiromer and placebo arms. Secondary endpoints will include hyperkalaemia events with K⁺ value >5.5 mEq/L, durable enablement of MRA at target dose, investigator-reported adverse events of hyperkalaemia, hyperkalaemia-related clinical endpoints and an overall RAASi use score (using a 0-8-point scale) comprising all-cause death, occurrence of cardiovascular hospitalization or usage of comprehensive heart failure medication.

CONCLUSION

The DIAMOND trial is designed to determine if patiromer can favourably impact K⁺ control in patients with HFrEF with hyperkalaemia or a history of hyperkalaemia leading to RAASi therapy compromise, and in turn improve RAASi use.

Evaluation and management of cancer patients presenting with acute cardiovascular disease: a Consensus Document of the Acute CardioVascular Care (ACVC) association and the ESC council of Cardio-Oncology-Part 1: acute coronary syndromes and acute pericardial diseases

Advances in treatment, common cardiovascular (CV) risk factors and the ageing of the population have led to an increasing number of cancer patients presenting with acute CV diseases. These events may be related to the cancer itself or the cancer treatment. Acute cardiac care specialists must be aware of these acute CV complications and be able to manage them. This may require an individualized and multidisciplinary approach. We summarize the most common acute CV complications of cytotoxic, targeted, and immune-based therapies. This is followed by a proposal for a multidisciplinary approach where acute cardiologists work close together with the treating oncologists, haematologists, and radiation specialists, especially in situations where immediate therapeutic decisions are needed. In this first part, we further focus on the management of acute coronary syndromes and acute pericardial diseases in patients with cancer.

Prevalence, clinical correlates, and outcomes of anaemia in multi-ethnic Asian patients with heart failure with reduced ejection fraction

Aims

Recent international heart failure (HF) guidelines recognize anaemia as an important comorbidity contributing to poor outcomes in HF, based on data mainly from Western populations. We sought to determine the prevalence, clinical correlates, and prognostic impact of anaemia in patients with HF with reduced ejection fraction across Asia.

Methods and results

We prospectively studied 3886 Asian patients (60 ± 13 years, 21% women) with HF (ejection fraction ≤40%) from 11 regions in the Asian Sudden Cardiac Death in Heart Failure study. Anaemia was defined as haemoglobin <13 g/dL (men) and <12 g/dL (women). Ethnic groups included Chinese (33.0%), Indian (26.2%), Malay (15.1%), Japanese/Korean (20.2%), and others (5.6%). Overall, anaemia was present in 41%, with a wide range across ethnicities (33–54%). Indian ethnicity, older age, diabetes, and chronic kidney disease were independently associated with higher odds of anaemia (all P < 0.001). Ethnicity modified the association of chronic kidney disease with anaemia (P_interaction = 0.045), with the highest adjusted odds among Japanese/Koreans [2.86; 95% confidence interval (CI) 1.96–4.20]. Anaemic patients had lower Kansas City Cardiomyopathy Questionnaire scores (P < 0.001) and higher risk of all‐cause mortality and HF hospitalization at 1 year (hazard ratio = 1.28, 95% CI 1.08–1.50) compared with non‐anaemic patients. The prognostic impact of anaemia was modified by ethnicity (P_interaction = 0.02), with the greatest hazard ratio in Japanese/Koreans (1.82; 95% CI 1.14–2.91).

Conclusions

Anaemia is present in a third to more than half of Asian patients with HF and adversely impacts quality of life and survival. Ethnic differences exist wherein prevalence is highest among Indians, and survival is most severely impacted by anaemia in Japanese/Koreans.

Concise review: Engineering myocardial tissue: the convergence of stem cells biology and tissue engineering technology

Advanced heart failure represents a leading public health problem in the developed world. The clinical syndrome results from the loss of viable and/or fully functional myocardial tissue. Designing new approaches to augment the number of functioning human cardiac muscle cells in the failing heart serve as the foundation of modern regenerative cardiovascular medicine. A number of clinical trials have been performed in an attempt to increase the number of functional myocardial cells by the transplantation of a diverse group of stem or progenitor cells. Although there are some encouraging suggestions of a small early therapeutic benefit, to date, no evidence for robust cell or tissue engraftment has been shown, emphasizing the need for new approaches. Clinically meaningful cardiac regeneration requires the identification of the optimum cardiogenic cell types and their assembly into mature myocardial tissue that is functionally and electrically coupled to the native myocardium. We here review recent advances in stem cell biology and tissue engineering and describe how the convergence of these two fields may yield novel approaches for cardiac regeneration.

Prognostic value of galectin-3, a novel marker of fibrosis, in patients with chronic heart failure: data from the DEAL-HF study

Aims

Biomarkers are increasingly being used in the management of patients with chronic heart failure (HF). Galectin-3 is a recently developed biomarker associated with fibrosis and inflammation, and it may play a role in cardiac remodeling in HF. We determined its prognostic value in patients with chronic HF.

Methods and results

Patients with chronic HF (New York Heart Association functional class III or IV) who participated in the Deventer–Alkmaar heart failure study were studied. Galectin-3 levels were determined at baseline using a novel optimized enzyme-linked immunosorbent assay. Univariate and multivariate analyses were used to determine the prognostic value of this biomarker. We studied 232 patients; their mean age was 71 ± 10 years, 72% were male, and 96% were in NYHA class III. During a follow-up period of 6.5 years, 98 patients died. Galectin-3 was a significant predictor of mortality risk after adjustment for age and sex, and severity of HF and renal dysfunction, as assessed by NT-proBNP and estimated glomerular filtration rate, respectively (hazard ratio per standard deviation 1.24, 95% CI 1.03–1.50, P = 0.026).

Conclusion

Plasma galectin-3 is a novel prognostic marker in patients with chronic HF. Its prognostic value is independent of severity of HF, as assessed by NT-proBNP levels, and it may potentially be used in the management of such patients.