Reduced mitochondrial pyruvate carrier expression in hearts with heart failure and reduced ejection fraction patients: ischemic vs. non-ischemic origin

Introduction and objectives

Mitochondrial pyruvate carrier (MPC) mediates the entry of pyruvate into mitochondria, determining whether pyruvate is incorporated into the Krebs cycle or metabolized in the cytosol. In heart failure (HF), a large amount of pyruvate is metabolized to lactate in the cytosol rather than being oxidized inside the mitochondria. Thus, MPC activity or expression might play a key role in the fate of pyruvate during HF. The purpose of this work was to study the levels of the two subunits of this carrier, named MPC1 and MPC2, in human hearts with HF of different etiologies.

Methods

Protein and mRNA expression analyses were conducted in cardiac tissues from three donor groups: patients with HF with reduced ejection fraction (HFrEF) with ischemic cardiomyopathy (ICM) or idiopathic dilated cardiomyopathy (IDC), and donors without cardiac pathology (Control). MPC2 plasma levels were determined by ELISA.

Results

Significant reductions in the levels of MPC1, MPC2, and Sirtuin 3 (SIRT3) were observed in ICM patients compared with the levels in the Control group. However, no statistically significant differences were revealed in the analysis of MPC1 and MPC2 gene expression among the groups. Interestingly, Pyruvate dehydrogenase complex (PDH) subunits expression were increased in the ICM patients. In the case of IDC patients, a significant decrease in MPC1 was observed only when compared with the Control group. Notably, plasma MPC2 levels were found to be elevated in both disease groups compared with that in the Control group.

Conclusion

Decreases in MPC1 and/or MPC2 levels were detected in the cardiac tissues of HFrEF patients, with ischemic or idiopatic origen, indicating a potential reduction in mitochondrial pyruvate uptake in the heart, which could be linked to unfavorable clinical features.

Soluble HLA-G levels in heart transplant recipients: Dynamics and correlation with clinical outcomes

PURPOSE

To describe the evolution of the serum levels of soluble HLA-G (s-HLA-G) during the first 12 months after heart transplantation (HT) and to correlate it with clinical outcomes.

METHODS

Observational study based in a single-center cohort of 59 patients who underwent HT between December-2003 and March-2010. Soluble HLA-G levels were measured from serum samples extracted before HT, and 1, 3, 6 and 12 months after HT. The cumulative burden of s-HLA-G expression during the first post-transplant year was assessed by means of the area under the curve (AUC) of s-HLA-G levels over time and correlated with the acute rejection burden -as assessed by a rejection score-, the presence of coronary allograft vasculopathy (CAV) grade ≥ 1 and infections during the first post-transplant year; as well as with long-term patient and graft survival. Mean follow-up was 12.4 years.

RESULTS

Soluble HLA-G levels decreased over the first post-transplant year (p = 0.020). The AUC of s-HLA-G levels during the first post-transplant year was higher among patients with infections vs. those without infections (p = 0.006). No association was found between the AUC of s-HLA-G levels and the burden of acute rejection or the development of CAV. Overall long-term survival, long-term survival free of late graft failure and cancer-free survival were not significantly different in patients with an AUC of s-HLA-G levels higher or lower than the median of the study population.

CONCLUSIONS

Soluble HLA-G levels decreased over the first year after HT. Higher HLA-G expression was associated with a higher frequency of infections, but not with the burden of acute rejection or the development of CAV, neither with long-term patient or graft survival.

Cancer in patients with heart failure: Incidence, risk factors and prognostic impact

AIMS

To assess the incidence of cancer diagnosis and cancer-related mortality in patients with heart failure (HF).

METHODS

Observational study based in a prospective cohort of patients with HF referred to a specialized Spanish clinic between 2010 and 2019. The observed incidence of malignancies (excluding non-melanoma skin cancer) was compared to that expected for the general Spanish population according to the Global Cancer Observatory.

RESULTS

We studied 1909 consecutive patients with HF. Over a median follow-up of 4.07 years, 165 new cases of malignancy were diagnosed. Observed age-standardized incidence rates of cancer were 861 (95% CI 618.4-2159.4) cases per 100,000 patients-years in men and 728.5 (95% CI 451.1-4308.7) cases per 100,000 patients-years in women; while age-standardized incidence rates of cancer expected for the general Spanish population were 479.4 cases per 100,000 patients-years in men (risk ratio = 1.80) and 295.5 cases per 100,000 patients-years in women (risk ratio = 2.46). Both a history of pre-existing malignancy at baseline and the development of new malignancies during follow-up were associated with reduced survival. Observed age-standardized cancer-related mortality was 344.1 (95% CI 202.1-1675) deaths per 100,000 patient-years in men and 217.0 (95% CI 32.8-3949.3) deaths per 100,000 patient-years in women; while age-standardized cancer-related mortality expected for the general Spanish population was 201.4 deaths per 100,000 patients-years in men (risk ratio = 1.71) and 96.2 deaths per 100,000 patients-years in women (risk ratio = 2.26).

CONCLUSION

Patients with HF showed higher incidence rates of cancer diagnosis and cancer-related mortality than those expected for the general population.

Comparison of predicted and observed mortality in patients with heart failure treated at a specialized unit

INTRODUCTION AND OBJECTIVES

To analyze survival in heart failure (HF) patients treated at a specialized unit.

METHODS

Prospective cohort-based study of HF patients treated at a specialized unit from 2011 to 2017. Observed 1- and 3-year mortality rates were compared with those predicted by the Meta-Analysis Global Group in Chronic Heart Failure (MAGGIC) risk score.

RESULTS

We studied 1280 patients, whose median MAGGIC risk score was 19 [interquartile range, 13-24]. Prescription rates of beta-blockers, angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, mineralocorticoid receptor antagonists, and sacubitril-valsartan were 93%, 67%, 22%, 73%, and 16%, respectively. The MAGGIC risk score showed good discrimination for mortality at 1 year (c-statistic=0.71) and 3 years (c-statistic=0.76). Observed mortality was significantly lower than predicted mortality, both at 1 year (6.2% vs 10.9%; observed/predicted ratio=0.57; P<.001) and at 3 years (16.7% vs 27.7%; observed/predicted ratio=0.60; P<.001). This discrepancy was found in several subgroups, except in patients aged> 70 years (29.9% vs 34.7%; observed/predicted ratio=0.86; P=.126) and in patients with ejection fraction> 40% (19.6% vs 20.7%; observed/predicted ratio=0.95; P=.640).

CONCLUSIONS

Mortality in HF patients treated at a specialized clinic was significantly lower than that predicted by the MAGGIC risk score.

P5455Serum microRNA-181a-5p expression pattern correlates with acute cellular rejection in heart transplantation

Background

Acute Cellular Rejection (ACR) remains a major complication in heart transplantation (HT). Since 1970, endomyocardial biopsy (EMB) has been the gold standard for ACR early detection. However, this invasive procedure has several limitations such as risk of complications, interobserver variability, false negative results and high cost. Therefore, a new non-invasive ACR biomarker is needed. Potential candidates could be microRNAs (miRs), small regulatory RNAs whose serum expression profiling could be modified in ACR patients. The aim of this study is the identification of differentially serum miRs expression patterns in ACR after HT.

Methods

Among HT performed in our Hospital (2013–2018), we selected patients with following criteria: i) “0R → 2R → 0R” EMB pattern for ACR (0R=no ACR, 2R=moderate ACR); ii) no antibody mediated rejection; iii) serum collected the same day as the EMBs. The 3 serum samples per patient matched in time with EMB were called “0Rs1 → 2Rs2 → 0Rs3”. In each of these serum samples, 179 miRs expression profile according manufacturer's instructions were analysed. Global Mean (GM) method was used to normalize our results expressed as miRs relative expression [2(–ΔCq)]. Expression pattern was defined as a 2 steps process: a significative rise (0Rs1 → 2Rs2) followed by a significative fall (2Rs2 → 0Rs3), or vice versa, in miR expression. Analysis of differences between 3 groups were calculated using one-way ANOVA with matched data and post-hoc Tukey test. ROC curve was generated for selected miRNA. A two-sided p<0.05 was considered statistically significant.

Results

21 patients and their serum “0Rs1 → 2Rs2 → 0Rs3” samples were included in the study. Among 179 miRs analysed, 5 miRs showed significative difference between 0Rs1 and 2Rs2, 3 miRs were over-expressed (miR-181a-5p, miR-339-3p, let-7f-5p) and 2 under-expressed (miR-505-3p, miR-2110). Only miR-181a-5p met significative difference between 2Rs2 and 0Rs3 showing a statistical significative rise/fall pattern. Serum miR-181a-5p ROC analysis demonstrated significant discrimination between biopsy proven ACR from no-ACR biopsy, AUC=0.692 (p=0.0335).

Differentially expressed miRs Mean relative expression 2(–ΔCq) (95% CI) Adjusted p-value (ANOVA) AUC (95% CI) 0Rs1 2Rs2 0Rs3 0Rs1 vs 2Rs2 2Rs2 vs 0Rs3 0Rs1 vs 0Rs3 miR-181–5p 0.80 (0.60–1.02) 1.11 (0.90–1.31) 0.86 (0.71–1.01) 0.0194 0.0225 NS 0.692 (0.529–0,855) Relative Expression 2(–ΔCq) and AUC expressed as mean (95% Confident Interval). NS: not significative.

Conclusion

Our findings suggest miR-181a-5p as a novel serological biomarker for detecting ACR after HT. After this preliminary discovery phase, miR-181a-5p is currently in a new validation phase to demonstrate its diagnostic performance.

Acknowledgement/Funding

This work was supported by a grant from isciii (PI15/02224) and it is part of the of the “CIBERCV”. Co-financed with FEDER Funds

Circulating Galectin-3 Following Heart Transplant: Long-term Dynamics and Prognostic Value

INTRODUCTION AND OBJECTIVES

Circulating galectin-3 (Gal-3) is elevated and significantly correlates with all-cause and cardiovascular mortality in patients with heart failure. However, the relationship between serum Gal-3 and heart transplant (HT) outcomes is unclear. The aim of this study was to describe the longitudinal trend and prognostic value of Gal-3 levels after HT.

METHODS

Banked serum samples were available from 122 HT recipients, collected before transplant and at 1, 3, 6, and 12 months posttransplant. Gal-3 levels in these serum samples were measured by enzyme immune assay. Multivariable Cox regression was performed to determine the prognostic value of 12-month posttransplant Gal-3 serum levels. The primary endpoint was the composite variable all-cause death or graft failure over long-term posttransplant follow-up.

RESULTS

Circulating Gal-3 concentration steadily decreased during the first year after HT (median values: pretransplant, 19.1 ng/mL; 1-year posttransplant, 14.6 ng/mL; P<.001). Circulating Gal-3 levels 1-year posttransplant were associated with an increased risk of all-cause death or graft failure (adjusted HR per 1 ng/mL, 1.04; 95%CI, 1.01-1.08; P=.008). The predictive accuracy of this biomarker was moderate: area under the ROC curve, 0.72 (95%CI, 0.60-0.82; P<.001).

CONCLUSIONS

Circulating Gal-3 steadily decreased during the first year after HT. However, 1-year posttransplant Gal-3 serum levels that remained elevated were associated with increased long-term risk of death and graft failure.

Conversion of heart transplant patients from standard to sustained-release tacrolimus requires a dosage increase

INTRODUCTION

It has been suggested that for adequate maintenance of tacrolimus levels, the total daily dosage should be increased when switching from the conventional twice-daily regimen tacrolimus (CT) to once-daily sustained-release tacrolimus (SR-T).

OBJECTIVE

To evaluate the safety and efficacy of a 25% increase in daily dosage when switching heart transplant (HT) patients from CT to SR-T.

METHODS

We switched 75 HT patients including 72% males and an overall mean age of 55.6 years from CT to SR-T using a 25% increase in daily dosage. We screened for adverse events by measurements of lipids, creatinine, glycemia, and tacrolimus in blood samples taken at 1, 3, 7, and 12 weeks after the conversion, as well as by repeated echocardiography and routine clinical examinations.

RESULTS

Just two patients (2.7%) were returned to CT because of failure of SR-T to attain therapeutic levels. In the remainder of subjects, tacrolimus levels remained stable, with trough values of 8.7±3.2, 8.7±2.9, 8.3±2.6, and 7.5±2.0 mg/dL, respectively. Twenty-three patients (31%) required no dosage change in the first 3 months, but 44 (33%) required one or two changes. No departure from therapeutic levels was associated with rejection; there was no case of severe intercurrent infection. We did not observe significant changes in glycemia, creatinine, lipid profile, or blood pressure.

CONCLUSIONS

Administration of SR-T at a dosage 25% higher than the daily dosage of CT was safe. It ensured adequate tacrolimus levels in one-third of patients. Nevertheless, strict analytical surveillance is necessary during the initial months to allow dosage adjustments and to detect the minority of patients for whom SR-T does not achieve therapeutic tacrolimus levels.

Usefulness of the INTERMACS Scale for predicting outcomes after urgent heart transplantation

INTRODUCTION AND OBJECTIVES

Our aim was to assess the prognostic value of the INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support) scale in patients undergoing urgent heart transplantation (HT).

METHODS

Retrospective analysis of 111 patients treated with urgent HT at our institution from April, 1991 to October, 2009. Patients were retrospectively assigned to three levels of the INTERMACS scale according to their clinical status before HT.

RESULTS

Patients at the INTERMACS 1 level (n=31) more frequently had ischemic heart disease (P=.03) and post-cardiothomy shock (P=.02) than patients at the INTERMACS 2 (n=55) and INTERMACS 3-4 (n=25) levels. Patients at the INTERMACS 1 level showed higher preoperative catecolamin doses (P=.001), a higher frequency of use of mechanical ventilation (P<.001), intraaortic balloon (P=.002) and ventricular assist devices (P=.002), and a higher frequency of preoperative infection (P=.015). The INTERMACS 1 group also presented higher central venous pressure (P=.02), AST (P=.002), ALT (P=.006) and serum creatinine (P<.001), and lower hemoglobin (P=.008) and creatinine clearance (P=.001). After HT, patients at the INTERMACS 1 level had a higher incidence of primary graft failure (P=.03) and postoperative need for renal replacement therapy (P=.004), and their long-term survival was lower than patients at the INTERMACS 2 (log rank 5.1, P=.023; HR 3.1, IC 95% 1.1-8.8) and INTERMACS 3-4 level (log rank 6.1, p=0.013; HR 6.8, IC 95% 1.2-39.1).

CONCLUSIONS

Our results suggest that the INTERMACS scale may be a useful tool to stratify postoperative prognosis after urgent HT.