Cardiac Biopsy Research Articles

Evaluation of serum levels of sCD40, sCD40L and s4-1BB in advanced heart failure and after heart transplant

Abstract Heart failure is one of the most important problems in public health. Although big advances had been reached in treatment, the prognosis of advanced heart failure is still reserved and the heart transplant is the main therapy for this stage of disease. Allograft rejection is responsible for mortality in transplantation patients and the diagnosis of this complication is made through an invasive diagnostic method – the cardiac biopsy. The inflammatory response has been described in cardiovascular disease and in allograft rejection process. The objective of this study is to evaluate levels of sCD40, sCD40L and s4-1BB (inflammatory biomarkers) in advanced heart failure and post heart transplant with allograft rejection comparing to normal individuals and post heart transplant patients with no allograft rejection. The study population comprised 38 patients undergoing heart transplant in our center. Fifteen patients had biomarkers dosed before heart transplant and twenty three patients had dosed just after procedure. In this group, six patients were enrolled in the study for clinical suspicion of rejection. Nineteen health persons composed the control group with age between 18 and 49 years. Plasma dosage of sCD40, sCD40L e s4-1BB was made by enzyme linked immunosorbentassay (ELISA). Mann-Whitney test, Wilcoxon and t test were used to analyse dates. Statistical analysis used GraphPad®Prism6 and the value p< 0,05 was considered statistical significant. Allograft rejection occurred in 6,26% of studied patients. There was no statistical difference in age, sex, comorbities as hypertension, diabetes or etiology of cardiomyopathy. Serum levels of sCD40, sCD40L e s4-1BB were higher in patients with advanced heart failure comparing to controls (p< 0,0001). There was no difference in these levels of sCD40 (p = 0,74) e sCD40L (p = 0,44) between groups with and without rejection. Levels of s4-1BB were significantly lower in patients with allograft rejection (p= 0,02). The sCD40/PCR and s4-1BB/PCR indexs were significantly higher in the group of patients with allograft rejection (p =0,02 e p= 0,0001). We concluded that sCD40, sCD40L e s4-1BB are biomarkers of severe heart failure. The serum level of s4-1BB could be a potential biomarker of allograft rejection and the association of sCD40 and s4-1BB with PCR could be a better strategy to this.

Differential echocardiographic profiles in immunoglobulin light chain and transthyretin amyloid cardiomyopathy: insights from speckle tracking analysis

Abstract Background Amyloid cardiomyopathy is mainly caused by two main subtypes of amyloidosis; immunoglobulin light chains cardiomyopathy (AL-CM) and transthyretin cardiomyopathy (TTR-CM). Purposes The aim of the present study was to elucidate the differences in echocardiographic findings between AL-CM and TTR-CM using speckle tracking echocardiography. Methods The study included patients with a confirmed diagnosis of cardiac amyloidosis through cardiac biopsy and who underwent transthoracic echocardiography between March 2013 and October 2022. The relative apical sparing index (RASI) was calculated using speckle tracking echocardiography: mean apical strain value/(mean basal strain value + mean mid strain value). Results The final study population consisted of 50 patients with a confirmed diagnosis of cardiac amyloidosis diagnosed pathologically (AL-CM: 21 patients, TTR-CM: 29 patients). Mean age was 72 ± 11 years, 70% being male. AL-CM exhibited a lower left ventricular mass index compared to TTR-CM (124.5 ± 48.9 vs. 152.2 ± 39.2 g/m2, P = 0.001). In 35 patients available with longitudinal strain analysis, no significant difference was observed in left ventricular global longitudinal strain between the two subgroups (-9.9 ± 4.8 vs. -9.3 ± 2.4% , P = 0.63). However, RASI was significantly lower in AL-CM compared to TTR-CM as shown in Figure (0.92 ± 0.29 vs. 1.46 ± 0.53, P = 0.001). Receiver operating characteristic curve analysis shows a RASI cut-off value of <1.0 proved useful in differentiating the diagnosis of AL-CM from TTR-CM (sensitivity: 81%, specificity: 70%, AUC:0.82), and RASI <1.0 remained a significant association with the diagnosis of AL-CM, even after adjusted by conventional echocardiographic variables. Conclusion Apical sparing phenomenon was more remarkable in TTR-CM compared with AL-CM, although global longitudinal strain was comparable between the two groups. RASI was useful for the discrimination of cardiac amyloidosis subtypes.

Cardiac magnetic resonance T1 imaging for the diagnosis of cardiac amyloidosis among patients with symptomatic heart failure

Abstract Background Cardiac amyloidosis (CA) is a significant cause of heart failure in elderly patients. However, specific signs in cardiac imaging are lacking, hence bone scintigraphy in combination with screening for monoclonal protein, or myocardial biopsy is required for the diagnosis. Cardiac magnetic resonance (CMR) imaging with T1 mapping is a promising diagnostic tool, which may allow to differentiate causes of left ventricular (LV) hypertrophy, particularly CA. Purpose The aim of this study was to test the diagnostic accuracy of T1 mapping for the diagnosis of CA in elderly patients with symptomatic heart failure and red flags for CA. Methods We prospectively enrolled 120 patients aged above 60 years with symptomatic heart failure NYHA II-IV, LV ejection fraction ≥ 40%, increased LV wall thickness of ≥ 12 mm end-diastolic on echocardiography, and elevated cardiac biomarkers (N-terminal pro-B-type natriuretic peptide (NT-proBNP) ≥ 1,000 ng/L, high-sensitivity cardiac troponin T (hs-cTnT) ≥ 14 ng/L). All patients underwent standardized quantitative CMR with a 3.0T scanner. 99mTc-DPD bone scintigraphy, blood screening for monoclonal protein, and, where applicable, cardiac biopsy, were performed as reference methods in all patients. Primary endpoint was diagnostic accuracy of native T1 mapping for the diagnosis of CA. Results 112 patients were included in the final analysis. Median age was 81.0 years (interquartile range 74.0–85.0 years), and 45% were female. CA was diagnosed in 38 patients (34%), of which 32 suffered from a Transthyretin (ATTR) and 6 patients from light chain (AL) amyloidosis. The areas under the receiver operating characteristic curves for native T1 were 0.713, 0.772, 0.836 for global, septal short-axis (SAX), and septal 4-chamber (4Ch) view measurements. The corresponding value of extracellular volume fraction (ECV) was 0.904 (Figure 1). Based on these results, we developed a new diagnostic algorithm for the diagnosis of CA including T1 septal 4Ch and ECV, with a sensitivity and positive predictive value of both 92.9% and a specificity and negative predictive value of 95.8% (Figure 2). Thereby, contrast application can be avoided in 33% of patients. A definite diagnosis could be provided in 81%. Conclusion CMR with T1 imaging provides a high diagnostic accuracy to diagnose CA in patients with symptomatic heart failure at risk for CA. These data may help to identify underlying causes in heart failure which require specific treatment. An earlier diagnosis of CA may improve outcome of these patients.Figure 1Figure 2

Proteomics-based computational modelling of myocardial metabolism for personalized phenotyping and outcome prediction in advanced heart failure

Abstract Background Perturbations of myocardial metabolism and energy depletion are well-established hallmarks of heart failure (HF), yet methods for their systematic assessment remain limited in humans [1]. Computational modelling of the heart of individual patients represents an emerging precision medicine approach for personalized diagnosis of specific disease mechanisms and tailored clinical decision-making [2,3]. Purpose To determine the ability of computational modelling of patient-specific myocardial metabolism to assess individual bioenergetic phenotypes and their prognostic implications in HF. Methods Based on proteomics-derived enzyme intensity profiles in cardiac biopsies, we recently developed a computational model of myocardial metabolism capturing all pathways along energy-delivering substrates are processed to generate ATP [4]. Using this framework, we studied the individual energetic state in 17 sex-matched nonfailing controls and 48 patients with advanced HF (LVEF 20±10%, 72.9% non-ischemic aetiology, 52.1% females, 29.8% diabetics) undergoing heart transplantation (n=25) or ventricular assist device (VAD) implantation (n=23). The bioenergetic impact of alterations in substrate availability and myocardial workload were simulated, and the model’s ability to predict myocardial reverse remodelling after VAD implantation was assessed. Results Compared to controls, HF patients had a reduced ATP production capacity (p<0.01), although there was considerable interindividual variance, ranging from severely decreased to normal values. While overall oxygen consumption was lower in failing hearts, the amount of ATP generated per mole of oxygen did not differ (p=0.16). Maximum uptake capacity of fatty acids, glucose, and amino acids was comparable. By contrast, maximum uptake capacity of ketone bodies and lactate was reduced in the failing heart (p for both <0.05). There was a shift from fatty acid to glucose utilization in most HF patients, depending on substrate availability and myocardial workload. The ratio of fatty acid to glucose oxidation distinguished patients with LVEF recovery >10% after VAD implantation (C-index 0.93, p<0.01; Picture 1B) and correlated significantly with improvement in post-operative LVEF (r=0.67, p<0.01). ATP production capacity was not associated with reverse remodelling after VAD implantation. Conclusions Computational modelling identified a subset of advanced HF patients with preserved myocardial metabolism despite a similar degree of systolic dysfunction. Myocardial substrate preference but not ATP production capacity was associated with myocardial recovery after VAD implantation, which suggests a potential for substrate manipulation as a therapeutic approach in those with deranged fuel use. Computational assessment of myocardial metabolism in HF may improve understanding of disease heterogeneity, individual risk stratification, and guidance of personalized clinical decision-making in the future.

Incidence of acute cellular and antibody mediated rejection in heart transplantation from a tertiary care center

Abstract Background Heart transplant greatly increases the survival in patients with end stage heart failure. However, cardiologists and cardiothoracic surgeons face difficulty in detecting rejection at times. Post-cardiac transplant surveillance biopsy remains the gold standard for diagnosing rejection and therapeutic intervention. Purpose The objective is to report our experience of monitoring rejection by endomyocardial biopsy (EMB). Methods The index study is an ambispective one where we evaluated all the patients who underwent heart transplant at our center from 1994 to 2021. Results Heart transplant were carried out in 72 patients within a period of 28 years, with majority being done after 2016. The patients mean age was 31.6 years (10-59 years). The commonest indication was dilated cardiomyopathy (67%) followed by ischemic cardiomyopathy (2.5%), congenital heart disease (7%) and other miscellaneous causes (5%). The mean age of donors was 31.8 years (14-55 years). Eight of the 72 patients died without any post cardiac transplant endomyocardial biopsy. The remaining 64 patients underwent cumulatively a total of 271 endomyocardial biopsy procedures. Majority of endomyocaridal biopsies contained three cores (range 1-7). First EMB procedure was performed in 17 (26.6%) patients within first seven days, 35(53.1%) within the second week and 12(20.3%) after 14 days. Histologically rejection was identified in 42 (66%) patients. Thirty-nine (61%) had only acute cellular rejection (ACR), one (1.6%) had only antibody mediated rejection (AMR) and two (3.1%) had mixed ACR and AMR. These 42 patients with rejection had a total of 90 (33.2%) episodes of ACR detected in 271 endomyocardial biopsies. Out of 90 ACR, 44 (48.9%) occurred in less than six months; seventeen (18.9% of 90 ACR) episodes occurred between six and 12 months and 29 (32.2%) after one year. The mean of presentation of first ACR episode was 36 weeks (range 5 days to 3.6 years). There were 172 endomyocardial procedures within one year of transplantation of which 61 (35%) showed rejection. Ninety-nine endomyocardial procedures were performed one year of transplantation of which 29 (29%) showed rejection. Most common grade in both the time period was ACR grade 1R (International Society for Heart and Lung Transplantation (ISHLT) 2004) (72.1% in ≤1 year and 65.5% in >1 year) followed by 2R and 3R. Thirty-eight (90.4%) of 42 patients expired in less than five years since transplantation. Two (4.8%) patients survived between five to ten years post transplantation and two (4.8%) survived more than ten years. The longest cardiac transplant recipient had completed 23 years since cardiac transplant and is alive till date. Conclusions EMB being the gold standard for cardiac allograft rejection, the cardiac pathologists need to be aware of the various grades of rejection including mixed rejection.Acute cellular rejection (ISHLT 2004)

SNORD3A: a new possible circulating biomarker of human heart failure

Abstract Background Heart failure (HF) is a complex clinical syndrome and the leading cause of mortality, morbidity and hospitalization in industrialized countries. Human cardiac biopsies are invaluable resources for identifying cardiac signaling pathways, however blood fractions and peripheral blood mononuclear cells (PBMCs) could be used as a source of surrogate biomarkers of signaling pathway activation in human heart failure. Purpose In the present study we aimed to identify novel circulating biomarkers mirroring human myocardial signaling in HF and to study the role played by SNORD3A in cardiomyocyte survival and death. Methods Cardiac left ventricle samples and PBLs from 8 HF patients undergoing heart transplantation and 2 control patients (CTRL) were analyzed by RNA sequencing (RNASeq) to identify transcripts that were regulated in both hearts and PBLs. Five identified transcripts, KCNQOT1, MIAT, SCRN1, MALAT1 and SNORD3A, were then validated by quantitative real-time PCR in PBMCs and in LVs. Next, we analyzed the expression of the Small Nucleolar RNA (snoRNA) SNORD3A in LVs and PBMCs from 8-week-old wild type C57BL/6 mice with pressure overload-induced HF by transverse aortic constriction (TAC). Sham-operated mice (sham) were used as controls. To further investigate the role of SNORD3A in cardiomyocyte function and survival, SNORD3A antisense oligonucleotides (SNOaso) and scramble control sequences (GFPaso) were synthesized and tested in cardiomyoblasts H9C2 cells under normoxic or hypoxic conditions to evaluate SNORD3A transcription levels, cell death and protein synthesis. Results SNORD3A expression was significantly increased in both LVs and PBMCs from HF patients compared to control subjects. Consistent with these results, SNORD3A levels were increased both in PBMCs and LVs from TAC mice compared to sham. In vitro hypoxia significantly increased SNORD3A expression levels in H9C2 cells, compared to normoxia. After SNOaso transfection, SNORD3A transcripts were downregulated, and they were further reduced following 3-hour-hypoxia. Depletion of SNORD3A levels increased cardiomyocyte death and reduced protein synthesis in H9C2 cells. Conclusions Our data suggest that SNORD3A might be involved in the regulation of cardiomyocyte survival in HF and could be useful for diagnostic and prognostic applications in HF.

Progression of myocardial fibrosis is the major determinant of heart failure hospitalization in patients undergoing transcatheter aortic valve implantation

Abstract Background Patient who are hospitalized for heart failure (HF) prior to transcatheter aortic valve implantation (TAVI) are associated with poor prognosis. In this study, we aimed to assess whether myocardial fibrosis (MF) in TAVI patients is strongly involved in prior heart failure hospitalization. Methods We performed a retrospective single-center study, including 93 patients who underwent cardiac biopsies before TAVI from December 2022 to December 2023. The extent of MF was assessed on Masson’s trichrome-stained tissue specimens, using a validated software "ImageJ". Results Prior hospitalization had significant association with BNP (HF hospitalization (+): 461.9[130.4-987.7] vs. HF hospitalization (-):125.3[78.2-228.6], p=0.0014) , aortic valve area index (AVAi) (0.43±0.02 vs. 0.51±0.01, p=0.002), left ventricular ejection fraction (LVEF) (54.4±2.8 vs. 67.2±1.6, p=0.0002), E/e’ (23.4±1.9 vs. 19.1±1.0, p=0.045), left atrial volume index (LAVI)(59.0±3.5 vs. 46.1±1.6, p=0.0013), global longitudinal strain (GLS) (13.2±1.0 vs. 15.7±0.5), and percent area of myocardial fibrosis(7.0[4.8-14.2] vs. 3.3[2.2-7.3], p=0.0002) Moreover, percent area of MF was the most reliable indicator (area under the curve: AUC= 0.75, p=0.0009) of prior heart failure hospitalization (figure 1) among HF parameters which include BNP (AUC=0.73, p<0.0001), AVAi (AUC=0.69, p=0.0024), LVEF(AUC=0.68,p=0.0005), E/e’ (AUC=0.63, p=0.051), LAVI (AUC=0.72, p=0.0022), GLS (AUC=0.65, p=0.035). Furthermore, the ROC curve analyses demonstrated that the best thresholds of LVEF and percent area of MF were 64.9% (60.9% sensitivity and 68.1% specificity) and 4.1% (91.7% sensitivity and 56.5% specificity) for heart failure hospitalization, respectively. When patients were divided into 4 groups according to LVEF 65% and percent area of myocardial fibrosis 4%, a stepwise increase in the proportion of heart failure hospitalization was found in the 4 groups (figure 2). Conclusions This study illustrates that extensive myocardial fibrosis was strongly associated with prior heart failure hospitalization in TAVI patients. Patients with advanced myocardial fibrosis due to aortic stenosis may benefit from earlier treatment with TAVI to prevent further progression of myocardial fibrosis.

Evaluation of the 2021 ESC recommendations for family screening in hereditary transthyretin cardiac amyloidosis

Abstract Background The 2021 European Society of Cardiology (ESC) screening recommendations for individuals carrying a pathogenic transthyretin amyloidosis (ATTR) variant (ATTRv) are based on expert opinion. We aimed to (1) determine the yield of ATTR cardiomyopathy (ATTR-CM) at baseline; (2) evaluate the performance of the 2021 ESC position statement on initiating screening for ATTRv carriers; (3) establish the value of first-line tests recommended in ATTRv carriers; and (4) examine the yield of serial evaluation. Methods We included 159 relatives (median age 55.6 [interquartile range 43.2-65.9] years, 52% male) at-risk for developing ATTR-CM from 10 centres. ATTR-CM diagnosis was defined as the presence of either 1) cardiac tracer uptake in bone scintigraphy as recommended; or 2) cardiac biopsy proven positive for ATTR. Our secondary endpoint was a composite of heart failure symptoms (NYHA class³II) and conduction disorders necessitating pacemaker implantation. An individual fulfilled screening criteria as proposed by the 2021 ESC position statement if: 1) cardiac screening was performed ~10 years prior to disease onset in the proband (or in other individuals with the same variant if disease onset in the family was unknown); or 2) had extracardiac amyloidosis as diagnosed by a Neurologist or Ophthalmologist. Results At baseline, 40/159 (25%) relatives were diagnosed with ATTR-CM. Of those 40 relatives, 20 (50%) met the secondary endpoint. Relatives diagnosed with ATTR-CM were significantly older (66.5 [61.0-75.2] vs. 49.2 [40.8-58.8] years, p<0.001)(Figure 1A). Figure 1B-C visualizes the yield of screening by screening indications of the 2021 ESC position statement. Both screening for age, extra-cardiac amyloidosis or both age and extra-cardiac amyloidosis as indication to screen had a 31% (n=17/54), 18% (n=2/11) and 68% (n=19/28) yield of ATTR-CM, respectively. Diagnosis of ATTR-CM in relatives without an indication to screen was rare (3%; n=2/66). As a result, indication to screen as proposed by the 2021 ESC position statement yielded an almost excellent negative predictive value (97%). Other independent pre-screening predictors were infrequently identified variants and male sex. Of note, 13% of relatives with ATTR-CM did not show any "red flags" of cardiac amyloidosis on electrocardiogram (ECG), echocardiogram, and laboratory parameters. Excluding those who meet the secondary endpoint (i.e. those who already should have been diagnosed based on symptoms), ATTR-CM diagnosis in the absence of "red flags" increased from 13% to 26%. The yield of repeat bone scintigraphy (n=41 ATTRv carriers; follow-up 3.1 [2.2-5.2] years) at 3-years’ interval was 9.4% (Figure 2). Conclusion The recommendations made by the 2021 ESC position statement are adequate. Clinicians should adhere to the 3-year repeat bone scintigraphy as progressing to ATTR-CM in the absence of "red flags" and symptoms is not uncommon.Cardiac amyloidosis at baselineATTR-CM development during follow-up

Significant correlation between the extent of myocardial fibrosis and heart failure parameters in patients undergoing transcatheter aortic valve implantation

Abstract Background Recent studies have demonstrated that the prognosis of patients undergoing transcatheter aortic valve implantation (TAVI) is determined by the presence of myocardial fibrosis. The aim of this study was to quantify myocardial fibrosis in tissues obtained through myocardial biopsy before TAVI and to evaluate the relationship between the extent of myocardial fibrosis and baseline cardiac parameters. Methods We performed a retrospective single-center study, including 93 patients who underwent cardiac biopsies before TAVI from December 2022 to December 2023. The extent of myocardial fibrosis was assessed on Masson’s trichrome-stained tissue specimens, using a validated software "ImageJ". Results Median percent area of myocardial fibrosis in the entire cohort was 4.7% (interquartile range: 2.5 - 7.9). A significant correlation was found between the extent of myocardial fibrosis and brain natriuretic peptide (r= 0.41 p=0.0001), left ventricular ejection fraction (r=0.34, p=0.0009), aortic valve area index (r=0.33, p=0.0017), and global longitudinal strain (r=0.52, p<0.001). Patients who experienced prior heart failure hospitalization had a significantly larger extent of myocardial fibrosis (3.3% vs. 7.0%, p=0.0002). Conclusions Extensive myocardial fibrosis was associated with various heart failure parameters in patients undergoing TAVI. Patients with a large extent of myocardial fibrosis may require early intervention and/or intensive heart failure medical therapy to prevent fibrosis progression.

Diversity of heart failure phenotypes in transthyretin amyloid cardiomyopathy. More than just heart failure with preserved ejection fraction

Introduction Current guidelines recommend suspecting transthyretin amyloid cardiomyopathy (ATTR-CM) in patients over 65 years of age with unexplained left ventricular (LV) hypertrophy in a non-dilated LV, heart failure (HF) and preserved ejection fraction (HFpEF), hypertrophic cardiomyopathy or severe aortic stenosis. However, there is evidence indicating a high prevalence of ATTR-CM in other HF phenotypes. As such, this study aimed to characterize the diversity of HF phenotypes of ATTR-CM by examining the LV ejection fraction and LV dilatation using echocardiography. Methods This multicentre, retrospective observational study included patients diagnosed with ATTR-CM between 2015–2023. The diagnosis was based on a positive cardiac biopsy or positive bone scintigraphy without monoclonal gammopathy. Echocardiographic measurements were categorized according to LV ejection fraction (LVEF) into HFpEF (LVEF ≥50%), HF with mildly reduced EF (HFmrEF, LVEF 40–49%), and HF with reduced EF (HFrEF, LVEF <40%). LV cavity size was categorized by LV end-diastolic diameter (LVEDD) and volume index (LVEDVi) as normal, moderately increased and severe dilatation. Results The study included 135 patients with ATTR-CM (mean age, 78 years; 89% male; 89% wild-type ATTR-CM). Most patients were screened for ATTR-CM because of unexplained HF and increased LV wall thickness (57%). Echocardiography showed LVEF <50% in 60% of the patients, with a significant portion presenting with HFrEF. Patients with LVEF <50% had higher NYHA class and elevated N-terminal pro-B-type natriuretic peptide levels than HFpEF patients. LV dilatation was observed in 43% of the patients, with 10% presenting with both LVEF <50% and severe LV dilatation. Conclusion This study revealed significant variability in HF phenotypes among patients with ATTR-CM, from HFpEF without LV dilatation to HFrEF with severe LV dilatation. Relying solely on HFpEF for screening may lead to under-diagnosis. These findings suggest the need for more comprehensive diagnostic criteria beyond echocardiographic measures to improve ATTR-CM detection and management.

A series of cases of transthyretin amyloid cardiomyopathy with negative bone scintigraphy but a confirmed positive endomyocardial biopsy

BackgroundBone scintigraphy (BS) is established as an accurate, non-invasive method for the diagnosis of transthyretin amyloid cardiomyopathy (ATTR-CM). In a real-life setting, however, some patients with no cardiac uptake on BS turn out to have cardiac-biopsy-confirmed ATTR-CM. We retrospectively included all patients diagnosed at the French Referral Center for ATTR-CM and who had data for BS and a cardiac biopsy.ResultsOf 271 patients with positive cardiac biopsy, 14 (5%) had no cardiac uptake on 99mTc-hydroxymethylene diphosphonate BS. Cardiac uptake was found in four of the seven patients who had a second BS assessment with 99mTc-3,3-diphosphono-1,2-propanodicarboxylic acid (DPD). A retrospective review of the BS data found low cardiac uptake in four patients (two with HMDP and two with both radiotracers). Ultimately, six of the 14 patients with a biopsy-confirmed diagnosis of ATTR-CM did not show any cardiac radiotracer uptake.ConclusionsAn endomyocardial biopsy may be necessary for confirming the diagnosis of ATTR-CM in patients with clinical and imaging signs of cardiac amyloidosis but no cardiac radiotracer uptake in BS.

Leveraging metabolism for better outcomes in heart failure.

Whilst metabolic inflexibility and substrate constraint have been observed in heart failure for many years, their exact causal role remains controversial. In parallel, many of our fundamental assumptions about cardiac fuel use are now being challenged like never before. For example, the emergence of sodium glucose cotransporter 2 inhibitor (SGLT2i) therapy as one of the four "pillars" of heart failure therapy is causing a revisit of metabolism as a key mechanism and therapeutic target in heart failure. Improvements in the field of cardiac metabolomics will lead to a far more granular understanding of the mechanisms underpinning normal and abnormal human cardiac fuel use, an appreciation of drug action, and novel therapeutic strategies. Technological advances and expanding biorepositories offer exciting opportunities to elucidate the novel aspects of these metabolic mechanisms. Methodologic advances include comprehensive and accurate substrate quantitation such as metabolomics and stable-isotope fluxomics, improved access to arterio-venous blood samples across the heart to determine fuel consumption and energy conversion, high quality cardiac tissue biopsies, biochemical analytics, and informatics. Pairing these technologies with recent discoveries in epigenetic regulation, mitochondrial dynamics, and organ-microbiome metabolic crosstalk will garner critical mechanistic insights in heart failure. In this state-of-the-art review, we focus on new metabolic insights, with an eye on emerging metabolic strategies for heart failure. Our synthesis of the field will be valuable for a diverse audience with an interest in cardiac metabolism.

The role of anti-AT1R and HLA donor-specific antibodies in histologic and molecular assessment of cardiac allograft biopsies

The role of anti-AT1R and HLA donor-specific antibodies in histologic and molecular assessment of cardiac allograft biopsies

Exercise Intolerance in McArdle Disease: A Role for Cardiac Impairment? A Preliminary Study in Humans and Mice.

Whether cardiac impairment can be fully discarded in McArdle disease-the paradigm of 'exercise intolerance', caused by inherited deficiency of the skeletal muscle-specific glycogen phosphorylase isoform ('myophosphorylase')-remains to be determined. Eight patients with McArdle disease and seven age/sex-matched controls performed a 15-minute moderate, constant-load cycle-ergometer exercise bout followed by a maximal ramp test. Electrocardiographic and two-dimensional transthoracic (for cardiac dimension's assessment) and speckle tracking [for left-ventricle global longitudinal (GLS) assessments] echocardiographic evaluations were performed at baseline. Electrocardiographic and GLS assessments were also performed during constant-load exercise and immediately upon maximal exertion. Four human heart biopsies were obtained in individuals without McArdle disease, and in-depth histological/molecular analyses were performed in McArdle and wild-type mouse hearts. Exercise intolerance was confirmed in patients ('second wind' during constant-load exercise, -55% peak power output vs controls). As opposed to controls, patients showed a decrease in GLS during constant-load exercise, especially upon second wind occurrence, but with no other between-group difference in cardiac structure/function. Human cardiac biopsies showed that all three glycogen phosphorylase-myophosphorylase, but also liver and especially brain-isoforms are expressed in the normal adult heart, thereby theoretically compensating for eventual myophosphorylase deficiency. No overall histological (including glycogen depots), cytoskeleton, metabolic or mitochondrial (morphology/network/distribution) differences were found between McArdle and wild-type mouse hearts, except for lower levels of pyruvate kinase M2 and translocase of outer membrane 20 kDa subunit in the former. This study provides preliminary evidence that cardiac structure and function seem to be preserved in patients with McArdle disease. However, the role for an impaired cardiac contractility associated with the second wind phenomenon should be further explored.

18F]-florbetaben PET/CT is sensitive for cardiac AL amyloidosis.

Often differential diagnosis between AL and ATTR amyloidosis is difficult. Concerning ATTR, sensitive diagnostic tool, as diphosphonate scintigraphy, was validated, instead of no imaging approach is as accurate in AL. Cardiac ultrasound and circulating biomarkers may raise the clinical suspicion but biopsy remains the only option for diagnosis. We aimed to explore the sensitivity of 18F-Florbetaben PET respect to blood tests or periumbilical fat (POF), cardiac, bone marrow (BM) or other tissues biopsies in a cohort of 33 patients.

A longitudinal evaluation of oxidative stress - mitochondrial dysfunction - ferroptosis genes in anthracycline-induced cardiotoxicity

BackgroundAntineoplastic medications, including doxorubicin, idarubicin, and epirubicin, have been found to adversely affect the heart due to oxidative stress - mitochondrial dysfunction - ferroptosis (ORMFs), which act as contributing attributes to anthracycline-induced cardiotoxicity. To better understand this phenomenon, the time-resolved measurements of ORMFS genes were analyzed in this study.MethodsThe effect of three anthracycline drugs on ORMFs genes was studied using a human 3D cardiac microtissue cell model. Transcriptome data was collected over 14 days at two doses (therapeutic and toxic). WGCNA identified key module-related genes, and functional enrichment analysis investigated the biological processes quantified by ssGSEA, such as immune cell infiltration and angiogenesis. Biopsies were collected from heart failure patients and control subjects. GSE59672 and GSE2965 were collected for validation. Molecular docking was used to identify anthracyclines’s interaction with key genes.ResultsThe ORMFs genes were screened in vivo or in vitro. Using WGCNA, six co-expressed gene modules were grouped, with MEblue emerging as the most significant module. Eight key genes intersecting the blue module with the dynamic response genes were obtained: CD36, CDH5, CHI3L1, HBA2, HSD11B1, OGN, RPL8, and VWF. Compared with control samples, all key genes except RPL8 were down-regulated in vitro ANT treatment settings, and their expression levels varied over time. According to functional analyses, the key module-related genes were engaged in angiogenesis and the immune system pathways. In all ANT-treated settings, ssGSEA demonstrated a significant down-regulation of angiogenesis score and immune cell activity, including Activated CD4 T cell, Immature B cell, Memory B cell, Natural killer cell, Type 1 T helper cell, and Type 2 T helper cell. Molecular docking revealed that RPL8 and CHI3L1 show significant binding affinity for anthracyclines.ConclusionThis study focuses on the dynamic characteristics of ORMFs genes in both human cardiac microtissues and cardiac biopsies from ANT-treated patients. It has been highlighted that ORMFs genes may contribute to immune infiltration and angiogenesis in cases of anthracycline-induced cardiotoxicity. A thorough understanding of these genes could potentially lead to improved diagnosis and treatment of the disease.

Myocardial transcriptomic analysis of diabetic patients with aortic stenosis: key role for mitochondrial calcium signaling

BackgroundType 2 diabetes (T2D) is a frequent comorbidity encountered in patients with severe aortic stenosis (AS), leading to an adverse left ventricular (LV) remodeling and dysfunction. Metabolic alterations have been suggested as contributors of the deleterious effect of T2D on LV remodeling and function in patients with severe AS, but so far, the underlying mechanisms remain unclear. Mitochondria play a central role in the regulation of cardiac energy metabolism.ObjectivesWe aimed to explore the mitochondrial alterations associated with the deleterious effect of T2D on LV remodeling and function in patients with AS, preserved ejection fraction, and no additional heart disease.MethodsWe combined an in-depth clinical, biological and echocardiography phenotype of patients with severe AS, with (n = 34) or without (n = 50) T2D, referred for a valve replacement, with transcriptomic and histological analyses of an intra-operative myocardial LV biopsy.ResultsT2D patients had similar AS severity but displayed worse cardiac remodeling, systolic and diastolic function than non-diabetics. RNAseq analysis identified 1029 significantly differentially expressed genes. Functional enrichment analysis revealed several T2D-specific upregulated pathways despite comorbidity adjustment, gathering regulation of inflammation, extracellular matrix organization, endothelial function/angiogenesis, and adaptation to cardiac hypertrophy. Downregulated gene sets independently associated with T2D were related to mitochondrial respiratory chain organization/function and mitochondrial organization. Generation of causal networks suggested a reduced Ca2+ signaling up to the mitochondria, with the measured gene remodeling of the mitochondrial Ca2+ uniporter in favor of enhanced uptake. Histological analyses supported a greater cardiomyocyte hypertrophy and a decreased proximity between the mitochondrial VDAC porin and the reticular IP3-receptor in T2D.ConclusionsOur data support a crucial role for mitochondrial Ca2+ signaling in T2D-induced cardiac dysfunction in severe AS patients, from a structural reticulum-mitochondria Ca2+ uncoupling to a mitochondrial gene remodeling. Thus, our findings open a new therapeutic avenue to be tested in animal models and further human cardiac biopsies in order to propose new treatments for T2D patients suffering from AS.Trial registrationURL: https://www.clinicaltrials.gov; Unique Identifier: NCT01862237.Graphical abstract

Internalisation of immunoglobulin light chains by cardiomyocytes in AL amyloidosis: what can biopsies tell us?

Background Cardiac involvement in systemic light chain amyloidosis (AL) leads to chronic heart failure and is a major prognosis factor. Severe cellular defects are provoked in cardiac cells by tissue-deposited amyloid fibrils of misfolded free immunoglobulin light chains (LCs) and their prefibrillar oligomeric precursors. Objective Understanding the molecular mechanisms behind cardiac cell cytotoxicity is necessary to progress in therapy and to improve patient management. One key question is how extracellularly deposited molecules exert their toxic action inside cardiac cells. Here we searched for direct evidence of amyloid LC uptake by cardiomyocytes in patient biopsies. Methods We immunolocalized LCs in cardiac biopsies from four AL cardiac amyloidosis patients and analysed histopathological images by high resolution confocal microscopy and 3D image reconstruction. Results We show, for the first time directly in patient tissue, the presence of LCs inside cardiomyocytes, and report their proximity to nuclei and to caveolin-3-rich areas. Our observations point to macropinocytosis as a probable mechanism of LC uptake. Conclusions Internalisation of LCs occurs in patient cardiomyocytes. This event could have important consequences for the pathogenesis of the cardiac disease by enabling interactions between amyloid molecules and cellular organelles inducing specific signalling pathways, and might bring new insight regarding treatment.

Efficacy of Computed Tomography-Based Evaluation of Myocardial Extracellular Volume Combined With Red Flags for Early Screening of Concealed Cardiac Amyloidosis in Patients With Atrial Fibrillation.

The prevalence of transthyretin amyloid cardiomyopathy (ATTR-CM) in atrial fibrillation (AF) patients remains unclear. We explored the efficacy of computed tomography-based myocardial extracellular volume (CT-ECV) combined with red flags for the early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.Methods and Results: Patients referred for AF ablation at Oita University Hospital were prescreened using the red-flag signs defined by echocardiographic or electrocardiographic findings, medical history, symptoms, and blood biochemical findings. Myocardial CT-ECV was quantified in red flag-positive patients using routine pre-AF ablation planning cardiac CT with the addition of delayed-phase cardiac CT scans. Patients with high (>35%) ECV were evaluated using technetium pyrophosphate (99 mTc-PYP) scintigraphy. A cardiac biopsy was performed during the planned AF ablation procedure if 99 mTc-PYP scintigraphy was positive. Between June 2022 and June 2023, 342 patients were referred for AF ablation. Sixty-seven (19.6%) patients had at least one of the red-flag signs. Myocardial CT-ECV was evaluated in 57 patients because of contraindications to contrast media, revealing that 16 patients had high CT-ECV. Of these, 6 patients showed a positive 99 mTc-PYP study, and 6 patients were subsequently diagnosed with wild-type ATTR-CM via cardiac biopsy and genetic testing. CT-ECV combined with red flags could contribute to the systematic early screening of concealed ATTR-CM in AF patients undergoing catheter ablation.

Evaluation of the 2021 ESC recommendations for family screening in hereditary transthyretin cardiac amyloidosis.

The 2021 European Society of Cardiology (ESC) screening recommendations for individuals carrying a pathogenic transthyretin amyloidosis variant (ATTRv) are based on expert opinion. We aimed to (i) determine the penetrance of ATTRv cardiomyopathy (ATTRv-CM) at baseline; (ii) examine the value of serial evaluation; and (iii) establish the yield of first-line diagnostic tests (i.e. electrocardiogram, echocardiogram, and laboratory tests) as per 2021 ESC position statement. We included 159 relatives (median age 55.6 [43.2-65.9] years, 52% male) at risk for ATTRv-CM from 10 centres. The primary endpoint, ATTRv-CM diagnosis, was defined as the presence of (i) cardiac tracer uptake in bone scintigraphy; or (ii) transthyretin-positive cardiac biopsy. The secondary endpoint was a composite of heart failure (New York Heart Association class ≥II) and pacemaker-requiring conduction disorders. At baseline, 40/159 (25%) relatives were diagnosed with ATTRv-CM. Of those, 20 (50%) met the secondary endpoint. Indication to screen (≤10 years prior to predicted disease onset and absence of extracardiac amyloidosis) had an excellent negative predictive value (97%). Other pre-screening predictors for ATTRv-CM were infrequently identified variants and male sex. Importantly, 13% of relatives with ATTRv-CM did not show any signs of cardiac involvement on first-line diagnostic tests. The yield of serial evaluation (n = 41 relatives; follow-up 3.1 [2.2-5.2] years) at 3-year interval was 9.4%. Screening according to the 2021 ESC position statement performs well in daily clinical practice. Clinicians should adhere to repeating bone scintigraphy after 3 years, as progressing to ATTRv-CM without signs of ATTRv-CM on first-line diagnostic tests or symptoms is common.