High-Sensitivity Troponin T and Soluble Form of AXL as Long-Term Prognostic Biomarkers after Heart Transplantation

First time ACS in patients with on-target lipid levels: Inflammation at admission and re-event rate at follow-up

BACKGROUND

Dyslipidaemia, inflammation and elevated Lp(a) levels are associated with the progression of atherosclerosis. This study investigates whether patients with a first-time presentation of chest pain and on-target LDL-C levels and intermediate FRS/ESC-Score risks, display a high inflammatory burden linked to myocardial injury and whether inflammation at admission affects the re-event rate up to 6 years follow-up.

METHODS

Blind assessments of novel inflammatory markers such as Glycoprotein A and B via nuclear magnetic resonance (NMR), cytokines, hsCRP, Neutrophil-to-Lymphocyte ratio (NLR) and Lipoprotein(a) levels were examined. Out of 198 chest pain patients screened, 97 met the inclusion criteria at admission.

RESULTS

cTnI(+) patients (>61 ng/L) with elevated Lipoprotein(a), showed significantly increased levels of Glycoprotein A and B, hsCRP, IL-6, a high NLR and a reduced left ventricular ejection fraction (%) compared to cTnI(-) individuals. Those patients, with a higher inflammatory burden at hospital admission (hsCRP, IL-6, Glycoprotein A and B, and Lipoprotein(a)) had a higher re-event rate at follow-up.

CONCLUSIONS

Inflammation and Lipoprotein(a) levels were particularly prominent in patients presenting with reduced left ventricular ejection fraction. Notably, Glycoproteins A/B emerge as novel markers of inflammation in these patients. Our study highlights the significantly higher impact of inflammatory burden in patients with chest pain and high level of myocardial damage than in those with lower myocardial affectation, even when they all had lipid levels well controlled. Inflammation at the time of admission influenced the re-event rate over a follow-up period of up to 6 years.

Postoperative, but Not Preoperative, MELD-3.0 Prognosticates 3-Month Procedural Success in Patients Undergoing Orthotopic Heart Transplantation

Background/Objectives: Multi-organ failure (MOF) often complicates advanced heart failure (HF), contributing to a poor prognosis. The Model of End-Stage Liver Disease 3.0 (MELD-3.0) scale incorporates liver and kidney function parameters. This study aims to evaluate the prognostic significance of the MELD-3.0 score in patients with advanced HF who have undergone heart transplantation (HTx). Methods: The MELD-3.0 score was computed using the average values of the international normalized ratio and bilirubin, creatinine, sodium, and albumin levels during a hospital stay following HTx. The average MELD-3.0 scores from the period of 1 month preceding HTx and 1 week after HTx were analyzed. The primary endpoint of the study was the 6-month total mortality, and the secondary endpoint was ICU hospitalization time after HTx. Results: The analysis included 106 patients undergoing HTx, with a median age of 53 years (44-63), 81% of whom were male. Within 6 months post-HTx, 17 patients (16%) died; those patients had a higher 1-week post-HTx MELD-3.0 score of 18.3 (14.5-22.7) in comparison to survivors, whose average score was 13.9 (9.5-16.4), p < 0.01. There was no difference in MELD 3.0 score in the pre-HTx period: 16.6 (11.4-17.8) vs. 12.3 (8.6-17.1), p = 0.36. The post-HTx MELD-3.0 score independently predicted death: RR 1.17 (95% CI 1.05-1.30), p < 0.01. A Receiver Operating Characteristic (ROC) determined the cut-off value of the MELD-3.0 score as 17.3 (AUC = 0.83; sensitivity-67%; specificity-86%). Survivors with scores above this value had a longer ICU hospitalization time: 7 (5.0-11.0) vs. 12 (8-20) days (p = 0.01). Conclusions: The post-HTx MELD-3.0 score serves as an independent predictor of an unfavorable prognosis in patients with advanced HF undergoing HTx. The evaluation of MELD-3.0 scores provides additional prognostic information in this population.

Microvascular dysfunction in heart transplantation is associated with altered cardiomyocyte mitochondrial structure and unimpaired excitation-contraction coupling

INTRODUCTION

Microvascular dysfunction (MVD) is a hallmark feature of chronic graft dysfunction in patients that underwent orthotopic heart transplantation (OHT) and is the main contributor to impaired long-term graft survival. The aim of this study was to determine the effect of MVD on functional and structural properties of cardiomyocytes isolated from ventricular biopsies of OHT patients.

METHODS

We included 14 patients post-OHT, who had been transplanted for 8.1 years [5.0; 15.7 years]. Mean age was 49.6 ± 14.3 years; 64% were male. Coronary microvasculature was assessed using guidewire-based coronary flow reserve(CFR)/index of microvascular resistance (IMR) measurements. Ventricular myocardial biopsies were obtained and cardiomyocytes were isolated using enzymatic digestion. Cells were electrically stimulated and subcellular Ca2+ signalling as well as mitochondrial density were measured using confocal imaging.

RESULTS

MVD measured by IMR was present in 6 of 14 patients with a mean IMR of 53±10 vs. 12±2 in MVD vs. controls (CTRL), respectively. CFR did not differ between MVD and CTRL. Ca2+ transients during excitation-contraction coupling in isolated ventricular cardiomyocytes from a subset of patients showed unaltered amplitudes. In addition, Ca2+ release and Ca2+ removal were not significantly different between MVD and CTRL. However, mitochondrial density was significantly increased in MVD vs. CTRL (34±1 vs. 29±2%), indicating subcellular changes associated with MVD.

CONCLUSION

In-vivo ventricular microvascular dysfunction post OHT is associated with preserved excitation-contraction coupling in-vitro, potentially owing to compensatory changes on the mitochondrial level or due to the potentially reversible cause of the disease.

Unique 40-year survival after heart transplantation with normal graft function and spontaneous operational tolerance

Unique 40-year survival after heart transplantation with normal graft function and spontaneous operational tolerance.

High sensitivity troponin I as a biomarker for cardiac allograft vasculopathy: Evaluation of diagnostic potential and clinical utility

INTRODUCTION

Cardiac allograft vasculopathy (CAV) limits long-term survival in heart transplant (HTx) recipients. The use of biomarkers in CAV surveillance has been studied, but none are used in clinical practice. The predictive value of high-sensitivity troponin I (hsTnI) has not been extensively investigated in HTx recipients.

METHODS

HTx patients undergoing surveillance coronary angiograms and enrolled in the Emory Cardiovascular Biobank had plasma hsTnI measured. CAV grade was assessed using ISHLT nomenclature. Multivariable cumulative link mixed modeling was performed to determine association between hsTnI level and CAV grade. Patients were followed for adverse outcomes over a median 10-year period. Kaplan-Meier survival analysis and Cox proportional hazard modeling were performed.

RESULTS

Three hundred and seventy-two angiograms were analyzed in 156 patients at a median 8.9 years after transplant. hsTnI levels were positively correlated with concurrent CAV grade after adjustment for age, age at transplant, sex, BMI, hypertension, diabetes, hyperlipidemia, estimated glomerular filtration rate, and history of acute cellular rejection (p = .016). In an adjusted Cox proportional hazard model, initial hsTnI level above the median (4.9 pg/mL) remained a predictor of re-transplantation or death (hazard ratio 1.82; 95% confidence interval 1.16-2.90; p = .01).

CONCLUSION

An elevated hsTnI level reflects severity of CAV and is associated with poor long-term outcomes in patients with HTx.

Prognostic Value of Soluble AXL in Serum from Heart Failure Patients with Preserved and Reduced Left Ventricular Ejection Fraction

Heart failure (HF) is classified according to the degree of reduction in left ventricular ejection fraction (EF) in HF with reduced, mildly reduced, and preserved EF. Biomarkers could behave differently depending on EF type. Here, we analyze the soluble form of the AXL receptor tyrosine kinase (sAXL) in HF patients with reduced and preserved EF. Two groups of HF patients with reduced (HFrEF; n = 134) and preserved ejection fraction (HFpEF; n = 134) were included in this prospective observational study, with measurements of candidate biomarkers and functional, clinical, and echocardiographic variables. A Cox regression model was used to determine predictors for clinical events: cardiovascular mortality and all-cause mortality. sAXL circulating values predicted outcome in HF: for a 1.0 ng/mL increase in serum sAXL, the mortality hazard ratio (HR) was 1.019 for HFrEF (95% CI 1.000 to 1.038) and 1.032 for HFpEF (95% CI 1.013 to 1.052). In a multivariable Cox regression analysis, sAXL and NT-proBNP were independent markers for all-cause and cardiovascular mortality in HFpEF. In contrast, only NT-proBNP remained significant in the HFrEF group. When analyzing the event-free survival at a mean follow-up of 3.6 years, HFrEF and HFpEF patients in the higher quartile of sAXL had a reduced survival time. Interestingly, sAXL is a reliable predictor for all-cause and cardiovascular mortality only in the HFpEF cohort. The results suggest an important role for AXL in HFpEF, supporting sAXL evaluation in larger clinical studies and pointing to AXL as a potential target for HF therapy.

Insight into Noninvasive Radiological Modalities to Detect Heart Transplant Rejection

Purpose Patients with end-stage heart failure who remain symptomatic even with exemplary medical and device therapy are treated with heart transplantation. Multitudes of endeavor have been contrived during the last decennium in the field of noninvasive tests to rule out heart transplant rejection (HTR). In spite of having supportive literature, noninvasive imaging techniques lack acceptable documentation of clinical robustness, and endomyocardial biopsy (EMB) still remains the gold standard. The aim of this review is to shed light on the existing noninvasive radiological modalities to detect rejection among heart transplant recipients.

Methods A comprehensive search was conducted for this review article on the basis of literature available including scientific databases of PubMed, Embase, and Google Scholar, using keywords of “Heart transplantation,” “Acute allograft rejection,” “Arrhythmias,” “Echocardiography,” “Speckle tracking echocardiography,” and “Cardiac magnetic resonance imaging” from inception until September 2020.

Results After preliminary screening of the databases, details regarding existent noninvasive radiological modalities to detect HTR were gathered and compiled in this review article. Currently, deformation imaging using speckle tracking and T2 time using cardiac magnetic resonance imaging can serve as screening tools based on which further invasive investigations can be planned. Standardization of blood-based and imaging modalities as screening and possible diagnostic tools for rejection would have obvious clinical and financial benefits in the care of growing number of post heart transplant recipients in our country.

Conclusion Diagnosis of allograft rejection in heart transplant recipients through noninvasive techniques is demanding. To unravel the potential of noninvasive radiological modalities that can serve as a standard-of-care test, a prospective multicentric study randomizing noninvasive modality as first strategy versus current EMB-based gold standard of care is the need of the hour.

Novel biomarkers useful in surveillance of graft rejection after heart transplantation

Heart transplantation (HTx) is considered the gold-standard therapy for the treatment of advanced heart failure (HF). The long-term survival in HTx is hindered by graft failure which represents one of the major limitations of the long-term efficacy of HTx. Endomyocardial biopsy (EMB) and the evaluation of donor-specific antibodies (DSA) are currently considered the essential diagnostic tools for surveillance of graft rejection. Recently, new molecular biomarkers (including cell-free DeoxyriboNucleic Acid, exosomes, gene profiling microarray, nanostring, reverse transcriptase multiplex ligation-dependent probe amplification, proteomics and immune profiling by quantitative multiplex immunofluorescence) provide useful information on mechanisms of graft rejection. The ambitious role of a similar change of perspective is aimed at a better and longer graft preservation.

Axl expression is increased in early stages of left ventricular remodeling in an animal model with pressure-overload

Background

AXL is a receptor tyrosine kinase that has been related to kidney and vascular disorders. Heart failure patients with reduced ejection fraction have higher AXL in serum than controls. No information about Axl expression with HF progression is available.

Methods

Thoracic transverse aortic constriction (TAC) was successfully performed on male Wistar rats (n = 25) with different constriction levels. Controls underwent sham surgery (n = 12). Echocardiography measurements were performed 4–8 weeks after surgery. Collagen deposition was measured with picrosirius red staining. Axl mRNA levels in left ventricle (LV), left kidney (LK) and ascending aorta (aAo) and the LV expression of cardiac remodeling and fibrogenic factors were quantified with real-time PCR. AXL LV protein levels were quantified with western blot and localization was analyzed by immunohistochemistry. Soluble AXL levels in plasma were assayed with ELISA.

Results

Successful TAC rats were classified into LV hypertrophy (LVH) or heart failure (HF), modeling the progressive cardiac changes after pressure overload. Collagen deposition was increased only in the HF group. LV Axl mRNA levels were higher in LVH and HF than in Sham rats, and correlated with LVHi, and hypertrophic and fibrogenic mediators. However, no association was found with LV systolic function. AXL was expressed in LV myocytes and other cell types. Concentration of circulating sAXL in plasma was increased in the LVH group compared to Sham and HF rats. Axl mRNA levels were similar in all groups in the LK and aAo.

Conclusions

Axl expression pattern suggests a role in the early progression of LV remodeling in HF but not in the later systolic dysfunction. The higher levels of circulating AXL found in HF patients most probably shed from the heart.

Macrophage phenotypes and Gas6/Axl signaling in apical lesions

Background/purpose

Macrophages participate in the periapical inflammation with pro-inflammatory M1 cells and anti-inflammatory M2 cells. Gas6/Axl signal is the responsible pathway for the activation of M1 and polarization of M2. The aim of this study was to compare the number of CD16⁺ M1 cells, CD206⁺ M2 cells, and Gas6/Axl expression between apical granulomas and radicular cysts.

Materials and methods

Twenty-four cases of granuloma and twenty of cysts were submitted to immunohistochemistry using anti-CD16 and anti-CD206 antibodies for determining M1 and M2 macrophages and investigating the cells with positive Gas6 and Axl expression.

Results

There were more numerous of M1 macrophages in radicular cysts (175.9 ± 87.7) compared to apical granuloma (116.6 ± 55.8), and M2 macrophages was higher in cysts (204.0 ± 97.6) than granuloma (152.9 ± 64.6). The level of Gas6/Axl expression were similar. There was a significant different in M1 macrophage (P = 0.014) between two diagnosis. In patients with or without root resorption, the number of M1 were 194.6 ± 57.2 compared with 139.1 ± 79.6. The number of M2 were 241.7 ± 81.4 and 164.6 ± 77.1. The expression of Axl was stronger in root resorption patients (191.1 ± 43.6), but the tendency in Gas6 expression was similar. Significant differences were noted in high M2 infiltration and Axl positive lesions.

Conclusion

It appears that macrophages associated with significantly higher numbers in radicular cysts than apical granuloma. Meanwhile, macrophages and Axl receptor was intensively expressed in patients with root resorption, related to severe inflammation.