Search

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): New National Excellence Program of the Ministry of Human Capacities Introduction Growing body of evidence suggests that distinct alterations in myocardial microRNA (miRNA) expression contribute to pressure overload (PO)-induced pathological cardiac remodeling. Nevertheless, it is still under intense investigation whether the changes in miRNA expression patterns are also associated with the decompensation of LV systolic function in case of PO-evoked LV hypertrophy (LVH). Hence, we aimed to characterize miRNA expression in PO-induced LVH with and without systolic heart failure (HF). Methods PO was evoked by abdominal aortic banding (AB) in male Sprague-Dawley rats. Age-matched, sham-operated animals served as controls. Functional and morphological alterations were assessed by echocardiography and histology. At the end of the experimental period, rats in the AB group were subcategorized based on ejection fraction [EF] into ABLVH (EF>40%) and ABHF groups (EF<40%). Global miRNA expression profiling was performed using next generation sequencing. Bioinformatics analysis was carried out to predict miRNA-target interactions. Expression of selected target genes was measured by qRT-PCR. Results Increased heart weight-to-tibial length, LV mass and fibrosis confirmed the development of pathological LVH in both the ABLVH and ABHF groups. Nevertheless, increased lung weight-to-tibial length, chamber dilatation and severely reduced EF was noted only in the ABHF and not in the ABLVH, when compared to the sham group. 50 miRNA showed different expression in the ABHF compared to the ABLVH group. Based on the altered gene expression profile, in silico bioinformatics analysis predicted several target genes. Among them, reduced mRNA expression level of Fmr1 (FMRP translational regulator 1), Zfpm2 (zinc finger protein, multitype 2), Wasl (WASP like actin nucleation promoting factor), Ets1 (ETS proto-oncogene 1) and Atg16l1 (Autophagy Related 16 Like 1) was confirmed in ABHF compared to ABLVH. Conclusions Decompensation of systolic function in PO-induced LVH is associated with unique miRNA profile leading to specific regulation of gene expression. [ABSTRACT FROM AUTHOR]

Background: There are few meta-analyses examining the prognostic value of right ventricular ejection fraction (RVEF) for a specific type of cardiovascular disease (CVD). The aim of this study was to compare the association of cardiac magnetic resonance (CMR)-derived RVEF with adverse outcomes for several specific types of CVD, using a robust Bayesian model-averaged meta-analysis., Methods: Three databases were searched for CMR articles reporting hazard ratios (HRs) of RVEF restricted to a specific type of CVD. For each specific type of CVD, Bayesian model-averaged meta-analyses with and without publication bias adjustments were conducted to evaluate the strength of evidence for RVEF according to the Bayes Factor (BF)., Results: Among 108 articles (21,166 patients) analyzing 11 CVD types, pooled HR for 5% reduction in RVEF assessed by publication bias-unadjusted, Bayesian model-averaged meta-analysis offered moderate or strong evidence of an association with outcomes for all types of CVD (HR: 1.07-1.37, BF 10 : 4.3-9.6*10 7 ). In contrast, a robust Bayesian model-averaged meta-analysis, adjusted for publication bias, found moderate or strong evidence in favor of an association of RVEF with outcomes only in hypertrophic cardiomyopathy (HR: 1.19, 95% CrI: 0.98-1.42, BF 10 : 5.0), dilated cardiomyopathy (HR: 1.16, 95% CrI: 1-1.22, BF 10 : 23.3), pulmonary hypertension (HR: 1.05, 95% CrI: 1-1.12, BF 10 : 3.0), and aortic stenosis (HR: 1.15, 95% CrI: 0.97-1.34, BF 10 : 4.2). There was weak evidence for an association of RVEF with adverse outcomes in seven other CVDs., Conclusions: In a Bayesian meta-analysis adjusted for publication bias, there was moderate or strong evidence for an association of RVEF with outcomes for only four CVDs. Additional data may strengthen evidence regarding other CVDs., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Numerous research projects focused on the management of acute pulmonary hypertension as Coronavirus Disease 2019 (COVID-19) might lead to hypoxia-induced pulmonary vasoconstriction related to acute respiratory distress syndrome. For that reason, inhalative therapeutic options have been the subject of several clinical trials. In this experimental study, we aimed to examine the hemodynamic impact of the inhalation of the SIN-1A formulation (N-nitroso-N-morpholino-amino-acetonitrile, the unstable active metabolite of molsidomine, stabilized by a cyclodextrin derivative) in a porcine model of acute pulmonary hypertension. Landrace pigs were divided into the following experimental groups: iNO (inhaled nitric oxide, n = 3), SIN-1A-5 (5 mg, n = 3), and SIN-1A-10 (10 mg, n = 3). Parallel insertion of a PiCCO system and a pulmonary artery catheter (Swan-Ganz) was performed for continuous hemodynamic monitoring. The impact of iNO (15 min) and SIN-1A inhalation (30 min) was investigated under physiologic conditions and U46619-induced acute pulmonary hypertension. Mean pulmonary arterial pressure (PAP) was reduced transiently by both substances. SIN-1A-10 had a comparable impact compared to iNO after U46619-induced pulmonary hypertension. PAP and PVR decreased significantly (changes in PAP: -30.1% iNO, -22.1% SIN-1A-5, -31.2% SIN-1A-10). While iNO therapy did not alter the mean arterial pressure (MAP) and systemic vascular resistance (SVR), SIN-1A administration resulted in decreased MAP and SVR values. Consequently, the PVR/SVR ratio was markedly reduced in the iNO group, while SIN-1A did not alter this parameter. The pulmonary vasodilatory impact of inhaled SIN-1A was shown to be dose-dependent. A larger dose of SIN-1A (10 mg) resulted in decreased PAP and PVR in a similar manner to the gold standard iNO therapy. Inhalation of the nebulized solution of the new SIN-1A formulation (stabilized by a cyclodextrin derivative) might be a valuable, effective option where iNO therapy is not available due to dosing difficulties or availability.

Coronary artery bypass surgery can result in endothelial dysfunction due to ischemia/reperfusion (IR) injury. Previous studies have demonstrated that DuraGraft helps maintain endothelial integrity of saphenous vein grafts during ischemic conditions. In this study, we investigated the potential of DuraGraft to mitigate endothelial dysfunction in arterial grafts after IR injury using an aortic transplantation model. Lewis rats (n = 7-9/group) were divided in three groups. Aortic arches from the control group were prepared and rings were immediately placed in organ baths, while the aortic arches of IR and IR + DuraGraft rats were preserved in saline or DuraGraft, respectively, for 1 h before being transplanted heterotopically. After 1 h after reperfusion, the grafts were explanted, rings were prepared, and mounted in organ baths. Our results demonstrated that the maximum endothelium-dependent vasorelaxation to acetylcholine was significantly impaired in the IR group compared to the control group, but DuraGraft improved it (control: 89 ± 2%; IR: 24 ± 1%; IR + DuraGraft: 48 ± 1%, p < 0.05). Immunohistochemical analysis revealed decreased intercellular adhesion molecule-1, 4-hydroxy-2-nonenal, caspase-3 and caspase-8 expression, while endothelial cell adhesion molecule-1 immunoreactivity was increased in the IR + DuraGraft grafts compared to the IR-group. DuraGraft mitigates endothelial dysfunction following IR injury in a rat bypass model. Its protective effect may be attributed, at least in part, to its ability to reduce the inflammatory response, oxidative stress, and apoptosis., (© 2024. The Author(s).)

Sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce major adverse cardiovascular events (MACE) in type 2 diabetic (T2DM) patients. Pharmacological selectivity of these agents to SGLT2 over SGLT1 is highly variant, with unknown clinical relevance. Genetically reduced SGLT1-but not SGLT2-activity correlates with lower risk of heart failure and mortality, therefore additional non-selective SGLT1 inhibition might be beneficial. In this prespecified meta-analysis, we included 6 randomized, placebo-controlled cardiovascular outcome trials of SGLT2 inhibitors assessing MACE in 57,553 patients with T2DM. Mixed-effects meta-regression revealed that pharmacological selectivity of SGLT2 inhibitors (either as continuous or dichotomized variable) had no significant impact on most outcomes. However, lower SGLT2 selectivity correlated with significantly lower risk of stroke (pseudo-R 2  = 78%; p = 0.011). Indeed, dual SGLT1/2 inhibitors significantly reduced the risk of stroke (hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.64-0.94), unlike selective agents (p for interaction = 0.018). The risk of diabetic ketoacidosis and genital infections was higher in both pharmacological groups versus placebo. However, hypotension occurred more often with non-selective SGLT2 inhibitors (odds ratio [OR], 1.87; 95% CI, 1.20-2.92) compared with selective agents (p for interaction = 0.044). In conclusion, dual SGLT1/2 inhibition reduces stroke in high-risk T2DM patients but has limited additional effect on other clinical outcomes., (© 2024. The Author(s).)

Heterozygous (HET) truncating variant mutations in the TTN gene (TTNtvs), encoding the giant titin protein, are the most common genetic cause of dilated cardiomyopathy (DCM). However, the molecular mechanisms by which TTNtv mutations induce DCM are controversial. Here, we studied 127 clinically identified DCM human cardiac samples with next-generation sequencing (NGS), high-resolution gel electrophoresis, Western blot analysis, and super-resolution microscopy in order to dissect the structural and functional consequences of TTNtv mutations. The occurrence of TTNtv was found to be 15% in the DCM cohort. Truncated titin proteins matching, by molecular weight, the gene sequence predictions were detected in the majority of the TTNtv+ samples. Full-length titin was reduced in TTNtv+ compared with TTNtv- samples. Proteomics analysis of washed myofibrils and stimulated emission depletion (STED) super-resolution microscopy of myocardial sarcomeres labeled with sequence-specific anti-titin antibodies revealed that truncated titin was structurally integrated into the sarcomere. Sarcomere length-dependent anti-titin epitope position, shape, and intensity analyses pointed at possible structural defects in the I/A junction and the M-band of TTNtv+ sarcomeres, which probably contribute, possibly via faulty mechanosensor function, to the development of manifest DCM.

Background: Heart transplantation (HTX) is the standard treatment for end-stage heart failure. However, reperfusion following an ischemic period can contribute to myocardial injury. Neutrophil infiltration, along with the subsequent release of tissue-degrading neutrophil elastase (NE)-related serine proteases and oxygen-derived radicals, is associated with adverse graft outcomes. The inhibition of cathepsin C (CatC) has been shown to block NE-related protease activation. We hypothesized that the CatC inhibitor BI-9740 improves graft function after HTX., Methods: In a rat model of HTX, the recipient Lewis rats were orally administered with either a placebo (n = 12) or BI-9740 (n = 11, 20 mg/kg) once daily for 12 days. Donor hearts from untreated Lewis rats were explanted, preserved in a cardioplegic solution, and subsequently heterotopically implanted. In vivo left-ventricular (LV) graft function was assessed after 1 h of reperfusion. The proteolytic activity of neutrophil serine proteases was determined in bone marrow lysates from BI-9740-treated and control rats. Additionally, myocardial morphological changes were examined, and heart samples underwent immunohistochemistry and western blot analysis., Results: The NE-related proteolytic activity in bone marrow cell lysates was markedly decreased in the BI-9740-treated rats compared to those of the placebo group. Histopathological lesions, elevated CatC and myeloperoxidase-positive cell infiltration, and nitrotyrosine immunoreactivity with an increased number of poly(ADP-ribose) polymerase (PARP)-1-positive cells were lowered in the hearts of animals treated with BI-9740 compared to placebo groups. Regarding the functional parameters of the implanted graft, improvements were observed in both systolic function (LV systolic pressure 110 ± 6 vs 74 ± 6 mmHg; dP/dt max 2782 ± 149 vs 2076 ± 167 mmHg/s, LV developed pressure, at an intraventricular volume of 200 µl, p < 0.05) and diastolic function in the hearts of BI-9740 treated animals compared with those receiving the only placebo. Furthermore, the administration of BI-9740 resulted in a shorter graft re-beating time compared to the placebo group. However, this study did not provide evidence of DNA fragmentation, the generation of both superoxide anions and hydrogen peroxide, correlating with the absence of protein alterations related to apoptosis, as evidenced by western blot in grafts after HTX., Conclusions: We provided experimental evidence that pharmacological inhibition of CatC improves graft function following HTX in rats., (© 2023. The Author(s).)

Although systolic function characteristically shows gradual impairment in pressure overload (PO)-evoked left ventricular (LV) hypertrophy (LVH), rapid progression to congestive heart failure (HF) occurs in distinct cases. The molecular mechanisms for the differences in maladaptation are unknown. Here, we examined microRNA (miRNA) expression and miRNA-driven posttranscriptional gene regulation in the two forms of PO-induced LVH (with/without systolic HF). PO was induced by aortic banding (AB) in male Sprague-Dawley rats. Sham-operated animals were controls. The majority of AB animals demonstrated concentric LVH and slightly decreased systolic function (termed as AB LVH ). In contrast, in some AB rats severely reduced ejection fraction, LV dilatation and increased lung weight-to-tibial length ratio was noted (referred to as AB HF ). Global LV miRNA sequencing revealed fifty differentially regulated miRNAs in AB HF compared to AB LVH . Network theoretical miRNA-target analysis predicted more than three thousand genes with miRNA-driven dysregulation between the two groups. Seventeen genes with high node strength value were selected for target validation, of which five (Fmr1, Zfpm2, Wasl, Ets1, Atg16l1) showed decreased mRNA expression in AB HF by PCR. PO-evoked systolic HF is associated with unique miRNA alterations, which negatively regulate the mRNA expression of Fmr1, Zfmp2, Wasl, Ets1 and Atg16l1., (© 2023. Springer Nature Limited.)

Introduction: The shortage of available donor hearts and the risk of ischemia/reperfusion injury restrict heart transplantation (HTX). Alpha-1-antitrypsin (AAT), a well-characterized inhibitor of neutrophil serine protease, is used in augmentation therapy to treat emphysema due to severe AAT deficiency. Evidence demonstrates its additional anti-inflammatory and tissue-protective effects. We hypothesized that adding human AAT in a preservation solution reduces graft dysfunction in a rat model of HTX following extended cold ischemic storage., Methods: The hearts from isogenic Lewis donor rats were explanted, stored for either 1h or 5h in cold Custodiol supplemented with either vehicle (1h ischemia, n=7 or 5h ischemia, n=7 groups) or 1 mg/ml AAT (1h ischemia+AAT, n=7 or 5h ischemia+AAT, n=9 groups) before heterotopic HTX. Left-ventricular (LV) graft function was evaluated in vivo 1.5h after HTX. Immunohistochemical detection of myeloperoxydase (MPO) was performed in myocardial tissue and expression of 88 gene quantified with PCR was analyzed both statistical and with machine-learning methods., Results: After HTX, LV systolic function (dP/dt max 1h ischemia+AAT 4197 ± 256 vs 1h ischemia 3123 ± 110; 5h ischemia+AAT 2858 ± 154 vs 5h ischemia 1843 ± 104mmHg/s, p <0.05) and diastolic function (dP/dt min 5h ischemia+AAT 1516 ± 68 vs 5h ischemia 1095 ± 67mmHg/s, p <0.05) at an intraventricular volume of 90µl were improved in the AAT groups compared with the corresponding vehicle groups. In addition, the rate pressure product (1h ischemia+AAT 53 ± 4 vs 1h ischemia 26 ± 1; 5h ischemia+AAT 37 ± 3 vs 5h ischemia 21 ± 1mmHg*beats/min at an intraventricular volume of 90µl; p <0.05) was increased in the AAT groups compared with the corresponding vehicle groups. Moreover, the 5h ischemia+AAT hearts exhibited a significant reduction in MPO-positive cell infiltration in comparison to the 5h ischemia group. Our computational analysis shows that ischemia+AAT network displays higher homogeneity, more positive and fewer negative gene correlations than the ischemia+placebo network., Discussion: We provided experimental evidence that AAT protects cardiac grafts from prolonged cold ischemia during HTX in rats., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Korkmaz-Icöz, Abulizi, Li, Korkmaz, Georgevici, Sayour, Loganathan, Canoglu, Karck and Szabó.)

Aims: We aimed to confirm that three-dimensional echocardiography-derived right ventricular ejection fraction (RVEF) is better associated with adverse cardiopulmonary outcomes than the conventional echocardiographic parameters., Methods: We performed a meta-analysis of studies reporting the impact of unit change of RVEF, tricuspid annular plane systolic excursion (TAPSE), fractional area change (FAC), and free-wall longitudinal strain (FWLS) on clinical outcomes (all-cause mortality and/or adverse cardiopulmonary outcomes). Hazard ratios (HRs) were rescaled by the within-study SDs to represent standardized changes. Within each study, we calculated the ratio of HRs related to a 1 SD reduction in RVEF versus TAPSE, or FAC, or FWLS, to quantify the association of RVEF with adverse outcomes relative to the other metrics. These ratios of HRs were pooled using random-effects models., Results: Ten independent studies were identified as suitable, including data on 1,928 patients with various cardiopulmonary conditions. Overall, a 1 SD reduction in RVEF was robustly associated with adverse outcomes (HR = 2.64 [95% CI, 2.18-3.20], P < .001; heterogeneity: I 2  = 65%, P = .002). In studies reporting HRs for RVEF and TAPSE, or RVEF and FAC, or RVEF and FWLS in the same cohort, head-to-head comparison revealed that RVEF showed significantly stronger association with adverse outcomes per SD reduction versus the other 3 parameters (vs TAPSE, HR = 1.54 [95% CI, 1.04-2.28], P = .031; vs FAC, HR = 1.45 [95% CI, 1.15-1.81], P = .001; vs FWLS, HR = 1.44 [95% CI, 1.07-1.95], P = .018)., Conclusion: Reduction in three-dimensional echocardiography-derived RVEF shows stronger association with adverse clinical outcomes than conventional right ventricular functional indices; therefore, it might further refine the risk stratification of patients with cardiopulmonary diseases., (Copyright © 2023 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Introduction: Myocardial bridge is a frequently detected congenital coronary anomaly which is kept benign. It is unique because it can cause a dynamic compression during systole., Objective: In this article, we focus on the detection and evaluation of morphological parameters that can determine the symptomatic bridges., Method: We summarize the invasive and noninvasive modalities regarding this topic. We also present our retrospective research when we studied the morphological features of the left anterior descendent bridges with coronarography which led to angina pectoris. We compared the prognosis of patients where only myocardial bridge was found to those where atherosclerosis also had been presented., Results: Intravascular ultrasound can be adapted for the visualization of myocardial bridge and for measuring the severity of compression. Intracoronary Doppler- and fractional flow reserve allow the appreciation of functional significance. Stress echocardiography is the most used non-invasive imaging modality in this field. According to our results, the group where only myocardial bridge was presented has more severe morphological features. The shortening of the tunneled segment was more expressed. The mortality during long term (appr. 10 years) follow-up was low. Meanwhile, our results have demonstrated that none of the morphological parameters influence mortality., Conclusion: There is an essential discrepancy between the phenomenon's high prevalence, the good prognosis, and the numerous case reports where the authors report about severe complications. Today we possess those invasive and non-invasive techniques which can help us to design prospective trials clarify the morphological features' functional significance. Orv Hetil. 2023; 164(14): 563-570.

Introduction: Endothelial dysfunction is a potential side effect of brain death (BD). Ischemia/reperfusion (IR) injury during heart transplantation may lead to further endothelial damage. Protective effects of alpha-1-antitrypsin (AAT), a human neutrophil serine protease inhibitor, have been demonstrated against IR injury. We hypothesized that AAT protects brain-dead rats' vascular grafts from IR injury., Methods: Donor rats were subjected to BD by inflation of a subdural balloon. After 5.5 h, aortic rings were immediately mounted in organ baths (BD, n = 6 rats) or preserved in saline, supplemented either with vehicle (BD-IR, n = 8 rats) or AAT (BD-IR + AAT, n = 14 rats) for 24 h. During organ bath experiment, rings from both IR groups were exposed to hypochlorite to simulate warm reperfusion-associated endothelial injury. Endothelial function was measured ex vivo. Immunohistochemical staining for caspases was carried out and DNA-strand breaks were evaluated using terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling. Data are presented as median (interquartile range)., Results: AAT improved IR-induced decreased maximum endothelium-dependent vasorelaxation to acetylcholine in the BD-IR + AAT aortas compared to the BD-IR group (BD: 83 (9-28) % versus BD-IR: 49 (39-60) % versus BD-IR + AAT: 64 (24-42) %, P < 0.05). Additionally, an increase in the rings' sensitivity to acetylcholine was noted after AAT (pD 2 -value: BD-IR + AAT: 7.35 (7.06-7.89) versus BD-IR: 6.96 (6.65-7.21), P < 0.05). Caspase-3, -8, -9, and -12 immunoreactivity and the number of terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive cells were significantly decreased by AAT., Conclusions: AAT alleviates endothelial dysfunction, prevents increased caspase-3, -8, -9, and -12 levels, and decreases apoptotic DNA breakage due to BD and IR injury. This suggests that AAT treatment may be therapeutically beneficial to reduce IR-induced vascular damage., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Ischemia/reperfusion injury (IRI) remains a challenge in coronary artery bypass grafting (CABG). Diabetic patients with coronary artery disease are more likely to require CABG and therefore run a high risk for cardiovascular complications. Conditioned medium (CM) from bone marrow-derived mesenchymal stem cells has been shown to have beneficial effects against IRI. We hypothesized that adding CM to physiological saline protects vascular grafts from IRI in diabetic rats. Bone-marrow derived cells were isolated from nondiabetic rat femurs/tibias, and CM was generated. As we previously reported, CM contains 23 factors involved in inflammation, oxidative stress, and apoptosis. DM was induced by streptozotocin administration. Eight weeks later, to measure vascular function, aortic rings were isolated and mounted in organ bath chambers (DM group) or stored in 4°C saline, supplemented either with a vehicle (DM-IR group) or CM (DM-IR+CM group). Although DM was associated with structural changes compared to controls, there were no functional alterations. However, compared to the DM group, in the DM-IR aortas, impaired maximum endothelium-dependent vasorelaxation in response to acetylcholine (DM 86.7 ± 0.1% vs. DM-IR 42.5 ± 2.5% vs. DM-IR+CM 61.9 ± 2.0%, p < 0.05) was improved, caspase-3, caspase-8, caspase-9, and caspase-12 immunoreactivity was decreased, and DNA strand breakage, detected by the TUNEL assay, was reduced by CM. We present the experimental finding that the preservation of vascular grafts with CM prevents endothelial dysfunction after IRI in diabetic rats. Targeting apoptosis by CM may contribute to its protective effect., Competing Interests: The authors declare that there is no conflict of interest regarding the publication of this paper., (Copyright © 2022 Sevil Korkmaz-Icöz et al.)

Aims: Inflammatory pathways are increasingly recognized as an important factor in the pathophysiology of both heart failure (HF) and atrial fibrillation (AF). However, there is no data about inflammation-related histological and molecular alterations in HF-associated AF. The objective of our study was to investigate inflammatory pathways and fibrosis in end-stage HF-associated AF., Methods and Results: Left atrial samples of 24 male patients with end stage ischemic HF undergoing heart transplantation were analysed. Twelve patients suffered from sustained AF while the others had no documented AF. The expression of inflammasome sensors and their downstream signalling were investigated by Western blot. No differences were observed in the expression of inflammasome sensors between the two groups, while cleaved caspase-1 increased tendentiously in the AF group (P = 0.051). Cleaved caspase-1 also showed significant correlation with the expression of interleukin-1β and its cleaved form in the total population and in the AF group (P < 0.05). The presence of myocardial and epicardial macrophages were assessed by ionized calcium-binding adaptor molecule 1 (Iba1) immunostaining. Number of macrophages showed a tendency towards elevation in the left atrial myocardium and epicardium of AF compared with SR group. The amount of total and interstitial fibrosis was determined on Masson's trichrome-stained sections. Histological assessment revealed no difference between AF and SR groups in the amount of either total or interstitial fibrosis., Conclusions: This is the first study on inflammation-related differences between HF with SR or AF showing elevated inflammasome activity and enhanced macrophage infiltration in left atrial samples of patients with AF., (© 2022 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Investigating the effect of sex on pressure unloading therapy in a clinical scenario is limited by several nonstandardized factors. Hence, we sought to study sex-related similarities and differences under laboratory conditions. Pressure overload was induced in male and female rats by aortic banding (AB) for 6 and 12 wk. Age-matched sham-operated animals served as controls. Pressure unloading was performed by aortic debanding at week 6 . Different aspects of myocardial remodeling were characterized by echocardiography, pressure-volume analysis, histology, qRT-PCR, and explorative proteomics. Hypertrophy, increased fetal gene expression, interstitial fibrosis, and prolonged active relaxation were noted in the AB groups at week 6 in both sexes. However, decompensation of systolic function and further deterioration of diastolic function only occurred in male AB rats at week 12 . AB induced similar proteomic alterations in both sexes at week 6 , whereas characteristic differences were found at week 12 . After debanding, regression of hypertrophy and recovery of diastolic function took place to a similar extent in both sexes. Nevertheless, fibrosis, transcription of β-myosin-to-α-myosin heavy chain ratio, and myocardial proteomic alterations were reduced to a greater degree in females than in males. Debanding exposed anti-remodeling properties in both sexes and prevented the functional decline in males. Female sex is associated with greater reversibility of fibrosis, fetal gene expression, and proteomic alterations. Nevertheless, pressure unloading exposes a more pronounced anti-remodeling effect on the functional level in males, which is attributed to the more progressive functional deterioration in AB animals. NEW & NOTEWORTHY The present study is the first to assess the role of sex on pressure unloading-induced reverse and anti-remodeling in a rat model of aortic banding and debanding. Our data indicate that female sex is associated with a greater reversibility of fibrosis, fetal gene expression, and proteomic alterations compared with males. Nevertheless, pressure unloading exposes more anti-remodeling effect on the functional level in males, which is attributed to the more rapid functional deterioration in aortic-banded animals.

Aims: We sought to investigate the correlation between speckle-tracking echocardiography (STE)-derived myocardial work (MW) and invasively measured contractility in a rat model of athlete's heart. We also assessed MW in elite athletes and explored its association with cardiopulmonary exercise test (CPET)-derived aerobic capacity., Methods and Results: Sixteen rats underwent a 12-week swim training program and were compared to controls (n = 16). STE was performed to assess global longitudinal strain (GLS), which was followed by invasive pressure-volume analysis to measure contractility [slope of end-systolic pressure-volume relationship (ESPVR)]. Global MW index (GMWI) was calculated from GLS curves and left ventricular (LV) pressure recordings. In the human investigations, 20 elite swimmers and 20 healthy sedentary controls were enrolled. GMWI was calculated through the simultaneous evaluation of GLS and non-invasively approximated LV pressure curves at rest. All subjects underwent CPET to determine peak oxygen uptake (VO2/kg). Exercised rats exhibited higher values of GLS, GMWI, and ESPVR than controls (-20.9 ± 1.7 vs. -17.6 ± 1.9%, 2745 ± 280 vs. 2119 ± 272 mmHg·%, 3.72 ± 0.72 vs. 2.61 ± 0.40 mmHg/μL, all PExercise < 0.001). GMWI correlated robustly with ESPVR (r = 0.764, P < 0.001). In humans, regular exercise training was associated with decreased GLS (-17.6 ± 1.5 vs. -18.8 ± 0.9%, PExercise = 0.002) but increased values of GMWI at rest (1899 ± 136 vs. 1755 ± 234 mmHg·%, PExercise = 0.025). GMWI exhibited a positive correlation with VO2/kg (r = 0.527, P < 0.001)., Conclusions: GMWI precisely reflected LV contractility in a rat model of exercise-induced LV hypertrophy and captured the supernormal systolic performance in human athletes even at rest. Our findings endorse the utilization of MW analysis in the evaluation of the athlete's heart., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Long-term graft patency determines the prognosis of revascularization after coronary artery bypass grafting (CABG). Ischemia-reperfusion (I/R) injury of the graft suffered during harvesting and after implantation might influence graft patency. Aspirin, a nonsteroidal anti-inflammatory drug improves the long-term patency of vein grafts. Whether aspirin has the same effect on arterial grafts is questionable. We aimed to characterize the beneficial effects of aspirin on arterial bypass grafts in a rodent revascularization model. We gave Lewis rats oral pretreatment of either aspirin ( n = 8) or saline ( n = 8) for 5 days, then aortic arches were explanted and stored in cold preservation solution. The third group ( n = 8) was a non-ischemia-reperfusion control. Afterwards the aortic arches were implanted into the abdominal aorta of recipient rats followed by 2 h of reperfusion. Endothelium-dependent vasorelaxation was examined with organ bath experiments. Immunohistochemical staining were carried out. Endothelium-dependent maximal vasorelaxation improved, nitro-oxidative stress and cell apoptosis decreased, and significant endothelial protection was shown in the aspirin preconditioned group, compared to the transplanted control group. Significantly improved endothelial function and reduced I/R injury induced structural damage were observed in free arterial grafts after oral administration of aspirin. Aspirin preconditioning before elective CABG might be beneficial on free arterial graft patency.

Background: Reduced cardiovascular risk in premenopausal women has been the focus of research in recent decades. Previous hypothesis-driven experiments have highlighted the role of sex hormones on distinct inflammatory responses, mitochondrial proteins, extracellular remodeling and estrogen-mediated cardioprotective signaling pathways related to post-ischemic recovery, which were associated with better cardiac functional outcomes in females. We aimed to investigate the early, sex-specific functional and proteomic changes following myocardial ischemia in an unbiased approach., Methods: Ischemia was induced in male (M-Isch) and female (F-Isch) rats with sc. injection of isoproterenol (85 mg/kg) daily for 2 days, while controls (M-Co, F-Co) received sc. saline solution. At 48 h after the first injection pressure-volume analysis was carried out to assess left ventricular function. FFPE tissue slides were scanned and analyzed digitally, while myocardial proteins were quantified by liquid chromatography-tandem mass spectrometry (LC-MS/MS) using isobaric labeling. Concentrations of circulating steroid hormones were measured with LC-MS/MS. Feature selection (PLS and PLS-DA) was used to examine associations among functional, proteomic and hormonal datasets., Results: Induction of ischemia resulted in 38% vs 17% mortality in M-Isch and F-Isch respectively. The extent of ischemic damage to surviving rats was comparable between the sexes. Systolic dysfunction was more pronounced in males, while females developed a more severe impairment of diastolic function. 2224 proteins were quantified, with 520 showing sex-specific differential regulation. Our analysis identified transcriptional, cytoskeletal, contractile, and mitochondrial proteins, molecular chaperones and the extracellular matrix as sources of disparity between the sexes. Bioinformatics highlighted possible associations of estrogens and their metabolites with early functional and proteomic alterations., Conclusions: Our study has highlighted sex-specific alterations in systolic and diastolic function shortly after ischemia, and provided a comprehensive look at the underlying proteomic changes and the influence of estrogens and their metabolites. According to our bioinformatic analysis, inflammatory, mitochondrial, chaperone, cytoskeletal, extracellular and matricellular proteins are major sources of intersex disparity, and may be promising targets for early sex-specific pharmacologic interventions., (© 2021. The Author(s).)

Aims: Interleukin-1β (IL-1β) is an important pathogenic factor in cardiovascular diseases including chronic heart failure (HF). The CANTOS trial highlighted that inflammasomes as primary sources of IL-1 β are promising new therapeutic targets in cardiovascular diseases. Therefore, we aimed to assess inflammasome activation in failing hearts to identify activation patterns of inflammasome subtypes as sources of IL-1β., Methods and Results: Out of the four major inflammasome sensors tested, expression of the inflammasome protein absent in melanoma 2 (AIM2) and NLR family CARD domain-containing protein 4 (NLRC4) increased in human HF regardless of the aetiology (ischaemic or dilated cardiomyopathy), while the NLRP1/NALP1 and NLRP3 (NLR family, pyrin domain containing 1 and 3) inflammasome showed no change in HF samples. AIM2 expression was primarily detected in monocytes/macrophages of failing hearts. Translational animal models of HF (pressure or volume overload, and permanent coronary artery ligation in rat, as well as ischaemia/reperfusion-induced HF in pigs) demonstrated activation pattern of AIM2 similar to that of observed in end-stages of human HF. In vitro AIM2 inflammasome activation in human Tohoku Hospital Pediatrics-1 (THP-1) monocytic cells and human AC16 cells was significantly reduced by pharmacological blockade of pannexin-1 channels by the clinically used uricosuric drug probenecid. Probenecid was also able to reduce pressure overload-induced mortality and restore indices of disease severity in a rat chronic HF model in vivo., Conclusions: This is the first report showing that AIM2 and NLRC4 inflammasome activation contribute to chronic inflammation in HF and that probenecid alleviates chronic HF by reducing inflammasome activation. The present translational study suggests the possibility of repositioning probenecid for HF indications., (© The Author(s) 2021. Published by Oxford University Press on behalf of the European Society of Cardiology.)

Vascular ischemia/reperfusion injury (IRI) in patients undergoing coronary artery bypass grafting can result in graft failure and the need for repeat revascularization procedures. DuraGraft ® has been shown to protect structure and function in saphenous vein grafts against IRI. We compared the effect of DuraGraft ® to saline solution on arterial grafts submitted to IRI. Rat thoracic aortic rings were harvested and immediately mounted in organ bath chambers (control, n = 7 rats) or underwent cold ischemic preservation either in saline (IR, n = 9 rats) or DuraGraft ® (IR+Dura, n = 9 rats). Vascular function was measured ex vivo and immunohistochemistry was performed. Impaired maximum vasorelaxation (R max ) to ACh in the IR-group compared to controls was ameliorated by DuraGraft ® , indicating an improvement in endothelial function (R max to ACh (%): IR + Dura 73 ± 2 vs. IR 48 ± 3, p < 0.05). Additionally, decreased aortic ring sensitivity to ACh (pD 2 -value: -log 50% maximum response) seen after IR in the saline group was increased by DuraGraft ® (pD 2 to ACh: IR+Dura 7.1 ± 0.1 vs. IR 6.3 ± 0.2, p < 0.05). Impaired maximum contractile response to phenylephrine and high potassium chloride concentrations in the IR group compared to controls was significantly improved by DuraGraft ® . DuraGraft ® alleviates vascular dysfunction following IRI by reducing nitro-oxidative stress and the expression of ICAM-1, without leukocytes engagement.

Selective sodium-glucose cotransporter 2 (SGLT2) inhibitors reduced the risk of hospitalization for heart failure in patients with or without type 2 diabetes (T2DM) in large-scale clinical trials. The exact mechanism of action is currently unclear. The dual SGLT1/2 inhibitor sotagliflozin not only reduced hospitalization for HF in patients with T2DM, but also lowered the risk of myocardial infarction and stroke, suggesting a possible additional benefit related to SGLT1 inhibition. In fact, several preclinical studies suggest that SGLT1 plays an important role in cardiac pathophysiological processes. In this review, our aim is to establish the clinical significance of myocardial SGLT1 inhibition through reviewing basic research studies in the context of SGLT2 inhibitor trials.

The use of hearts with left-ventricular (LV) hypertrophy (LVH) could offer an opportunity to extend the donor pool for cardiac transplantation. We assessed the effects of LVH in 18-month-old spontaneously hypertensive stroke-prone (SHRSP) donor rats and following transplantation. In donors, cardiac function and structural alterations were assessed. Then, the hearts were transplanted into young normotensive-rats. We evaluated LV graft function 1 h after transplantation. The myocardial expression of 92 genes involved in apoptosis, inflammation, and oxidative-stress was profiled using PCR-array. Compared to controls, SHRSP-rats developed LVH, had increased LV systolic performance (slope of the end-diastolic pressure-volume (PV) relationship: 1.6±0.2 vs 0.8±0.1mmHg/μl, p<0.05) accompanied by diastolic dysfunction [prolonged time constant of LV pressure decay (Tau: 15.8±0.6 vs 12.3±0.5ms) and augmented diastolic stiffness (LV end-diastolic PV relationship: 0.103±0.012 vs 0.045±0.006mmHg/ml), p<0.05]. They presented ECG changes, myocardial fibrosis, and increased nitrotyrosine immunoreactivity and plasma troponin-T and creatine kinase-CM levels. After transplantation, even though the graft contractility was better in SHRSP rats compared to controls, the adverse impact of ischemia/reperfusion-injury on contractility was not altered (E es ratio after versus before transplantation: 32% vs 29%, p>0.05). Whereas nitrotyrosine immunoreactivity was higher, myeloperoxidase-positive cell infiltration was decreased in the SHRSP+transplanted compared to control+transplanted. Among the tested genes, LVH was associated with altered expression of 38 genes in donors, while transplantation of these hearts resulted in the change of four genes. Alterations in 18-month-old donor hearts, as a consequence of hypertension and LVH, were not associated with graft dysfunction in the early phase of reperfusion after transplantation., (© 2021. The Author(s).)

Myocardial sodium-glucose cotransporter 1 (SGLT1) has been shown to be upregulated in humans with heart failure (HF) with or without diabetes. In vitro studies have linked SGLT1 to increased nitro-oxidative stress in cardiomyocytes. We aimed to assess the relation between left ventricular (LV) SGLT1 expression and the extent of nitro-oxidative stress in two non-diabetic rat models of chronic heart failure (HF) evoked by either pressure (TAC, n = 12) or volume overload (ACF, n = 12). Sham-operated animals (Sham-T and Sham-A, both n = 12) served as controls. Both TAC and ACF induced characteristic LV structural and functional remodeling. Western blotting revealed that LV SGLT1 protein expression was significantly upregulated in both HF models (both p < 0.01), whereas the phosphorylation of ERK1/2 was decreased only in ACF; AMPKα activity was significantly reduced in both models. The protein expression of the Nox4 NADPH oxidase isoform was increased in both TAC and ACF compared with respective controls (both p < 0.01), showing a strong positive correlation with SGLT1 expression ( r = 0.855, p < 0.001; and r = 0.798, p = 0.001, respectively). Furthermore, SGLT1 protein expression positively correlated with the extent of myocardial nitro-oxidative stress in failing hearts assessed by 3-nitrotyrosin ( r = 0.818, p = 0.006) and 4-hydroxy-2-nonenal ( r = 0.733, p = 0.020) immunostaining. Therefore, LV SGLT1 protein expression was upregulated irrespective of the nature of chronic hemodynamic overload, and correlated significantly with the expression of Nox4 and with the level of myocardial nitro-oxidative stress, suggesting a pathophysiological role of SGLT1 in HF.

Vascular ischemia/reperfusion injury (IRI) contributes to graft failure and adverse clinical outcomes following coronary artery bypass grafting. Sodium-glucose-cotransporter (SGLT)-2-inhibitors have been shown to protect against myocardial IRI, irrespective of diabetes. We hypothesized that adding canagliflozin (CANA) (an SGLT-2-inhibitor) to saline protects vascular grafts from IRI. Aortic rings from non-diabetic rats were isolated and immediately mounted in organ bath chambers (control, n = 9-10 rats) or underwent cold ischemic preservation in saline, supplemented either with a DMSO vehicle (IR, n = 8-10 rats) or 50µM CANA (IR + CANA, n = 9-11 rats). Vascular function was measured, the expression of 88 genes using PCR-array was analyzed, and feature selection using machine learning was applied. Impaired maximal vasorelaxation to acetylcholine in the IR-group compared to controls was significantly ameliorated by CANA (IR 31.7 ± 3.2% vs. IR + CANA 51.9 ± 2.5%, p < 0.05). IR altered the expression of 17 genes. Ccl2 , Ccl3 , Ccl4 , CxCr4 , Fos , Icam1 , Il10 , Il1a and Il1b have been found to have the highest interaction. Compared to controls, IR significantly upregulated the mRNA expressions of Il1a and Il6 , which were reduced by 1.5- and 1.75-fold with CANA, respectively. CANA significantly prevented the upregulation of Cd40, downregulated NoxO1 gene expression, decreased ICAM-1 and nitrotyrosine, and increased PECAM-1 immunoreactivity. CANA alleviates endothelial dysfunction following IRI.

Aims: While global longitudinal strain (GLS) is considered to be a sensitive marker of left ventricular (LV) function, it is significantly influenced by loading conditions. We hypothesized that global myocardial work index (GMWI), a novel marker of LV function, may show better correlation with load-independent markers of LV contractility in rat models of pressure-induced or volume overload-induced heart failure., Methods and Results: Male Wistar rats underwent either transverse aortic constriction (TAC; n = 12) or aortocaval fistula creation (ACF; n = 12), inducing LV pressure or volume overload, respectively. Sham procedures were performed to establish control groups (n = 12/12). Echocardiographic loops were obtained to determine GLS and GMWI. Pressure-volume analysis with transient occlusion of the inferior caval vein was carried out to calculate preload recruitable stroke work (PRSW), a load-independent 'gold-standard' parameter of LV contractility. Myocardial samples were collected to assess interstitial and perivascular fibrosis area and also myocardial atrial-type natriuretic peptide (ANP) and brain-type natriuretic peptide (BNP) relative mRNA expression. Compared with controls, GLS was substantially lower in the TAC group (-7.0 ± 2.8 vs. -14.5 ± 2.5%; P < 0.001) and was only mildly reduced in the ACF group (-13.2 ± 2.4 vs. -15.4 ± 2.0%, P < 0.05). In contrast with these findings, PRSW and GMWI were comparable with sham in TAC (110 ± 26 vs. 116 ± 68 mmHg; 1687 ± 275 mmHg% vs. 1537 ± 662 mmHg%; both P = NS), while it was found to be significantly reduced in ACF (58 ± 14 vs. 111 ± 40 mmHg; 1328 ± 411 vs. 1934 ± 308 mmHg%, both P < 0.01). In the pooled population, GMWI (r = 0.70; P < 0.001) but not GLS (r = -0.23; P = 0.12) showed a strong correlation with PRSW. GLS correlated with interstitial (r = 0.61; P < 0.001) and perivascular fibrosis area (r = 0.54; P < 0.001), and also with myocardial ANP (r = 0.85; P < 0.001) and BNP relative mRNA expression (r = 0.75; P < 0.001), while GMWI demonstrated no or only marginal correlation with these parameters., Conclusions: Being significantly influenced by loading conditions, GLS may not be a reliable marker of LV contractility in heart failure induced by pressure or volume overload. GMWI better reflects contractility in haemodynamic overload states, making it a more robust marker of systolic function, while GLS should be considered as an integrative marker, incorporating systolic function, haemodynamic loading state, and adverse tissue remodelling of the LV., (© 2021 The Authors. ESC Heart Failure published by John Wiley & Sons Ltd on behalf of European Society of Cardiology.)

Background: We aimed to identify sex differences in the network properties and to recognize the geometric alteration effects of long-term swim training in a rat model of exercise-induced left ventricular (LV) hypertrophy., Methods: Thirty-eight Wistar rats were divided into four groups: male sedentary, female sedentary, male exercised and female exercised. After training sessions, LV morphology and function were checked by echocardiography. The geometry of the left coronary artery system was analysed on pressure-perfused, microsurgically prepared resistance artery networks using in situ video microscopy. All segments over > 80 μm in diameter were studied using divided 50-μm-long cylindrical ring units of the networks. Oxidative-nitrative (O-N) stress markers, adenosine A 2A and estrogen receptor (ER) were investigated by immunohistochemistry., Results: The LV mass index, ejection fraction and fractional shortening significantly increased in exercised animals. We found substantial sex differences in the coronary network in the control groups and in the swim-trained animals. Ring frequency spectra were significantly different between male and female animals in both the sedentary and trained groups. The thickness of the wall was higher in males as a result of training. There were elevations in the populations of 200- and 400-μm vessel units in males; the thinner ones developed farther and the thicker ones closer to the orifice. In females, a new population of 200- to 250-μm vessels appeared unusually close to the orifice., Conclusions: Physical activity and LV hypertrophy were accompanied by a remodelling of coronary resistance artery network geometry that was different in both sexes.

In patients undergoing coronary artery bypass grafting (CABG), ischemia/reperfusion injury (IRI) is the main contributor to organ dysfunction. Aging-induced vascular damage may be further aggravated during CABG. Favorable effects of conditioned medium (CM) from mesenchymal stem cells (MSCs) have been suggested against IRI. We hypothesized that adding CM to saline protects vascular grafts from IRI in rats. We found that CM contains 28 factors involved in apoptosis, inflammation, and oxidative stress. Thoracic aortic rings from 15-month-old rats were explanted and immediately mounted in organ bath chambers (aged group) or underwent 24 h of cold ischemic preservation in saline-supplemented either with vehicle (aged-IR group) or CM (aged-IR+CM group), prior to mounting. Three-month-old rats were used as referent young animals. Aging was associated with an increase in intima-to-media thickness, an increase in collagen content, higher caspase-12 mRNA levels, and immunoreactivity compared to young rats. Impaired endothelium-dependent vasorelaxation to acetylcholine in the aged-IR group compared to the aged-aorta was improved by CM (aged 61 ± 2% vs. aged-IR 38 ± 2% vs. aged-IR+CM 50 ± 3%, p < 0.05). In the aged-IR group, the already high mRNA levels of caspase-12 were decreased by CM. CM alleviates endothelial dysfunction following IRI in 15-month-old rats. The protective effect may be related to the inhibition of caspase-12 expression.

Aims/hypothesis: Large cardiovascular outcome trials demonstrated that the cardioprotective effects of sodium-glucose cotransporter 2 (SGLT2) inhibitors might reach beyond glucose-lowering action. In this meta-analysis, we sought to evaluate the potential infarct size-modulating effect of SGLT2 inhibitors in preclinical studies., Methods: In this preregistered meta-analysis (PROSPERO: CRD42020189124), we included placebo-controlled, interventional studies of small and large animal models of myocardial ischaemia-reperfusion injury, testing the effect of SGLT2 inhibitor treatment on myocardial infarct size (percentage of area at risk or total area). Standardised mean differences (SMDs) were calculated and pooled using random-effects method. We evaluated heterogeneity by computing Τ 2 and I 2 values. Meta-regression was performed to explore prespecified subgroup differences according to experimental protocols and their contribution to heterogeneity was assessed (pseudo-R 2 values)., Results: We identified ten eligible publications, reporting 16 independent controlled comparisons on a total of 224 animals. Treatment with SGLT2 inhibitor significantly reduced myocardial infarct size compared with placebo (SMD = -1.30 [95% CI -1.79, -0.81], p < 0.00001), referring to a 33% [95% CI 20%, 47%] difference. Heterogeneity was moderate (Τ 2  = 0.58, I 2  = 60%). SGLT2 inhibitors were only effective when administered to the intact organ system, but not to isolated hearts (p interaction <0.001, adjusted pseudo-R 2  = 47%). While acute administration significantly reduced infarct size, chronic treatment was superior (p interaction <0.001, adjusted pseudo-R 2  = 85%). The medications significantly reduced infarct size in both diabetic and non-diabetic animals, favouring the former (p interaction = 0.030, adjusted pseudo-R 2  = 12%). Treatment was equally effective in rats and mice, as well as in a porcine model. Individual study quality scores were not related to effect estimates (p = 0.33). The overall effect estimate remained large even after adjusting for severe forms of publication bias., Conclusions/interpretation: The glucose-lowering SGLT2 inhibitors reduce myocardial infarct size in animal models independent of diabetes. Future in vivo studies should focus on clinical translation by exploring whether SGLT2 inhibitors limit infarct size in animals with relevant comorbidities, on top of loading doses of antiplatelet agents. Mechanistic studies should elucidate the potential relationship between the infarct size-lowering effect of SGLT2 inhibitors and the intact organ system.

Although regular exercise training is associated with cardiovascular benefits, the increased risk of atrial arrhythmias has been observed after vigorous exercise and has been related to oxidative stress. We aimed at investigating exercise-induced atrial remodeling in a rat model of an athlete's heart and determining sex-specific differences. Age-matched young adult rats were divided into female exercised, female control, male exercised, and male control groups. After exercised animals completed a 12-week-long swim training protocol, echocardiography and in vivo cardiac electrophysiologic investigation were performed. Additionally, atrial histological and gene expression analyses were carried out. Post-mortem atrial weight data and histological examination confirmed marked atrial hypertrophy. We found increased atrial gene expression of antioxidant enzymes along with increased nitro-oxidative stress. No gene expression alteration was found regarding markers of pathological remodeling, apoptotic, proinflammatoric, and profibrotic processes. Exercise training was associated with a prolonged right atrial effective refractory period. We could not induce arrhythmias by programmed stimulation in any groups. We found decreased expression of potassium channels. Female gender was associated with lower profibrotic expression and collagen density. Long-term, balanced exercise training-induced atrial hypertrophy is not associated with harmful electrical remodeling, and no inflammatory or profibrotic response was observed in the atrium of exercised rats.

Background: Exercise training is associated with hypertrophy of left ventricle (LV). The aim of the present study is to evaluate sex differences in the adaptation of the coronary contractile function in physiological left ventricular hypertrophy induced by long-term swim training., Methods: Thirty-two Wistar rats were randomly divided into 4 groups: exercised male (ExM), exercised female (ExF), untrained control male (CoM), and untrained control female (CoF). The trained animals underwent a 12-week-long swim training program. After finishing the training program, LV morphology and function were checked by echocardiography. The spontaneous tone, thromboxane (TxA2) agonist-induced vascular contractility and non-endothelial dilatation of the isolated intramural coronary resistance artery were examined by pressure microangiometry. The thromboxane receptor (TxA2R) protein expression in the wall of coronary arteries was examined using immunohistochemistry., Results: The LV mass index was significantly higher in the ExM and ExF groups, furthermore the LV mass index was significantly higher in female than in male animals. ExM animals had lower spontaneous tone than ExF. TxA2 agonist-induced tone was raised only in ExF animals. The resistance coronary artery of exercised male animals had a significantly lower level of TxA2R positivity compared to exercised females., Conclusions: Both sexes broaden their range of contractility following chronic swimming, but the vessel tone shifted toward contraction in exercised female rats, while these values shifted toward relaxation in males. These observations underline the significance of identifying potential gender differences in the chronic exercise-induced coronary vascular remodeling in human athletes.

Background: Brain death (BD) has been suggested to induce coronary endothelial dysfunction. Ischemia/reperfusion (IR) injury during heart transplantation may lead to further damage of the endothelium. Previous studies have shown protective effects of conditioned medium (CM) from bone marrow-derived mesenchymal stem cells (MSCs) against IR injury. We hypothesized that physiological saline-supplemented CM protects BD rats' vascular grafts from IR injury., Methods: The CM from rat MSCs, used for conservation purposes, indicates the presence of 23 factors involved in apoptosis, inflammation, and oxidative stress. BD was induced by an intracranial-balloon. Controls were subjected to a sham operation. After 5.5 h, arterial pressures were measured in vivo. Aortic rings from BD rats were harvested and immediately mounted in organ bath chambers (BD group, n = 7) or preserved for 24 h in 4 °C saline-supplemented either with a vehicle (BD-IR group, n = 8) or CM (BD-IR+CM group, n = 8), prior to mounting. Vascular function was measured in vitro. Furthermore, immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) have been performed., Results: BD in donors was associated with significantly impaired hemodynamic parameters and higher immunoreactivity of aortic myeloperoxidase (MPO), nitrotyrosine, caspase-3, caspase-8, caspase-9, and caspase-12 compared to sham-operated rats. In organ bath experiments, impaired endothelium-dependent vasorelaxation to acetylcholine in the BD-IR group compared to BD rats was significantly improved by CM (maximum relaxation to acetylcholine: BD 81 ± 2% vs. BD-IR 50 ± 3% vs. BD-IR + CM 72 ± 2%, p < 0.05). Additionally, the preservation of BD-IR aortic rings with CM significantly lowered MPO, caspase-3, caspase-8, and caspase-9 immunoreactivity compared with the BD-IR group. Furthermore, increased mRNA expression of vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1 in the aortas from the BD-IR rats compared to BD group were significantly decreased by CM., Conclusions: The preservation of BD rats' vascular grafts with CM alleviates endothelial dysfunction following IR injury, in part, by reducing levels of inflammatory response and caspase-mediated apoptosis.

Background: Longitudinal strain (LS) is a sensitive marker of systolic function. Recent findings suggest that both myocardial contractility and loading conditions determine LS. The aim of this study was to investigate whether LS reflects the connection of cardiac contractility to afterload (termed ventriculoarterial coupling [VAC]) rather than mere contractility in rat models of hemodynamic overload-induced heart failure (HF)., Methods: Pressure overload-induced HF was evoked by transverse aortic constriction (TAC; n = 14). Volume overload-induced HF was established by an aortocaval fistula (ACF; n = 12). Age-matched sham-operated animals served as controls for TAC (n = 14) and ACF (n = 12), respectively. Pressure-volume analysis was carried out to compute contractility (slope of end-systolic pressure-volume relationship [ESPVR]), afterload (arterial elastance [E a ]), and VAC (E a /ESPVR). Preload was evaluated by meridional end-diastolic wall stress. Speckle-tracking echocardiography was performed to assess LS., Results: The TAC group presented with maintained ESPVR, increased E a , and enhanced meridional end-diastolic wall stress. In contrast, the ACF group was characterized by reduced ESPVR, decreased E a , and enhanced meridional end-diastolic wall stress. VAC increased in both HF groups. Furthermore, LS was also impaired in both HF models (-5.9 ± 0.6% vs -12.9 ± 0.5%, TAC vs Sham t [P < .001], and -11.7 ± 0.7% vs -13.5 ± 0.4%, ACF vs Sham a [P = .048]). Statistical analysis revealed that strain parameters were determined predominantly by afterload in the TAC group and by contractility in the ACF group, while preload had a minor effect. In the entire study population, LS showed a correlation with VAC (R = 0.654, P < .001) but not with ESPVR (R = 0.058, P = .668)., Conclusions: Under pathophysiologic conditions when both contractility and afterload become altered, LS reflects VAC rather than mere contractility., (Copyright © 2020 American Society of Echocardiography. Published by Elsevier Inc. All rights reserved.)

Hearts are usually procured from brain-dead (BD) donors. However, brain death may induce hemodynamic instability, which may contribute to posttransplant graft dysfunction. We hypothesized that BD-donor heart preservation with a conditioned medium (CM) from mesenchymal stem cells (MSCs) would improve graft function after transplantation. Additionally, we explored the PI3K pathway's potential role. Rat MSCs-derived CM was used for conservation purposes. Donor rats were either exposed to sham operation or brain death by inflation of a subdural balloon-catheter for 5.5 hours. Then, the hearts were explanted, stored in cardioplegic solution-supplemented with either a medium vehicle (BD and sham), CM (BD + CM), or LY294002, an inhibitor of PI3K (BD + CM + LY), and finally transplanted. Systolic performance and relaxation parameters were significantly reduced in BD-donors compared to sham. After transplantation, systolic and diastolic functions were significantly decreased, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL)-positive cells and endonuclease G positive cells were increased in the BD-group compared to sham. Preservation of BD-donor hearts with CM resulted in a recovery of systolic graft function (dP/dt max : BD + CM: 3148 ± 178 vs BD: 2192 ± 94 mm Hg/s at 110 µL, P < .05) and reduced apoptosis. LY294002 partially lowered graft protection afforded by CM in the BD group. Our data suggest that PI3K/Akt pathway is not the primary mechanism of action of CM in improving posttransplant cardiac contractility and preventing caspase-independent apoptosis., (© 2020 The Authors. American Journal of Transplantation published by Wiley Periodicals LLC on behalf of The American Society of Transplantation and the American Society of Transplant Surgeons.)

Background: Whereas selective sodium-glucose cotransporter 2 (SGLT2) inhibitors consistently showed cardiovascular protective effects in large outcome trials independent of the presence of type 2 diabetes mellitus (T2DM), the cardiovascular effects of dual SGLT1/2 inhibitors remain to be elucidated. Despite its clinical relevance, data are scarce regarding left ventricular (LV) SGLT1 expression in distinct heart failure (HF) pathologies. We aimed to characterize LV SGLT1 expression in human patients with end-stage HF, in context of the other two major glucose transporters: GLUT1 and GLUT4., Methods: Control LV samples (Control, n = 9) were harvested from patients with preserved LV systolic function who went through mitral valve replacement. LV samples from HF patients undergoing heart transplantation (n = 71) were obtained according to the following etiological subgroups: hypertrophic cardiomyopathy (HCM, n = 7); idiopathic dilated cardiomyopathy (DCM, n = 12); ischemic heart disease without T2DM (IHD, n = 14), IHD with T2DM (IHD + T2DM, n = 11); and HF patients with cardiac resynchronization therapy (DCM:CRT, n = 9, IHD:CRT, n = 9 and IHD-T2DM:CRT, n = 9). We measured LV SGLT1, GLUT1 and GLUT4 gene expressions with qRT-PCR. The protein expression of SGLT1, and activating phosphorylation of AMP-activated protein kinase (AMPKα) and extracellular signal-regulated kinase 1/2 (ERK1/2) were quantified by western blotting. Immunohistochemical staining of SGLT1 was performed., Results: Compared with controls, LV SGLT1 mRNA and protein expressions were significantly and comparably upregulated in HF patients with DCM, IHD and IHD + T2DM (all P < 0.05), but not in HCM. LV SGLT1 mRNA and protein expressions positively correlated with LVEDD and negatively correlated with EF (all P < 0.01). Whereas AMPKα phosphorylation was positively associated with SGLT1 protein expression, ERK1/2 phosphorylation showed a negative correlation (both P < 0.01). Immunohistochemical staining revealed that SGLT1 expression was predominantly confined to cardiomyocytes, and not fibrotic tissue. Overall, CRT was associated with reduction of LV SGLT1 expression, especially in patients with DCM., Conclusions: Myocardial LV SGLT1 is upregulated in patients with HF (except in those with HCM), correlates significantly with parameters of cardiac remodeling (LVEDD) and systolic function (EF), and is downregulated in DCM patients with CRT. The possible role of SGLT1 in LV remodeling needs to be elucidated.

Heart transplantation remains the definitive therapy of end-stage heart failure. Ischemia-reperfusion injury occurring during transplantation is a primary determinant of long-term outcome of heart transplantation and primary graft insufficiency. Modification of the nitric oxide/soluble guanylate cyclase/cyclic guanosine monophosphate signaling pathway appears to be one of the most promising among the pharmacological interventional options. We aimed at characterizing the cardio-protective effects of the soluble guanylate cyclase stimulator riociguat in a rat model of heterotopic heart transplantation. Donor Lewis rats were treated orally with either riociguat or placebo for two days (n = 9) in each transplanted group and (n = 7) in donor groups. Following explantation, hearts were heterotopically transplanted. After one hour reperfusion, left ventricular pressure-volume relations and coronary blood flow were recorded. Molecular biological measurements and histological examination were also completed. Left ventricular contractility (systolic pressure: 117 ± 13 vs. 48 ± 5 mmHg, p < 0.001; dP/dt max : 2963 ± 221 vs. 1653 ± 159 mmHg/s, p < 0.001), active relaxation (dP/dt min : -2014 ± 305 vs. -1063 ± 177 mmHg/s, p = 0.02; all at 120 µl of left ventricular volume), and alteration of coronary blood flow standardized to heart weight (2.55 ± 0.32 vs. 1.67 ± 0.22 ml/min/g, p = 0.03) were markedly increased following preconditioning with riociguat. Myocardial apoptosis markers were also significantly reduced in the riociguat pretreated group as well as the antioxidant markers were elevated. Pharmacological preconditioning with riociguat decreases ischemia-reperfusion injury and improves donor organ function in our animal model of heart transplantation. Therefore, riociguat might be a potential cardioprotective agent.

The major source of heart transplantation comes from brain-dead (BD) donors. However, brain death and myocardial ischemia/reperfusion injury during transplantation may lead to cardiac dysfunction and hemodynamic instability. A previous work demonstrated that pre-treatment of BD donors with dopamine improved the graft survival of heart allograft in recipient after transplantation. However, low-dose dopamine treatment might result in tachycardia and hypertension. Our previous experimental study showed that pre-treatment of BD donor rats with the dopamine derivate N-octanoyl dopamine (NOD), devoid of any hemodynamic effects, improved graft function after transplantation. Herein, we hypothesized that NOD confers superior myocardial protection than dopamine, in terms of graft function. Male Lewis donor rats were either subjected to sham-operation or brain death via a subdurally placed balloon followed by 5.5 h monitoring. Then, the hearts were explanted and heterotopically transplanted into Lewis recipient rats. Shortly before the onset of reperfusion, continuous intravenous infusion of either NOD (14.7 μg/kg/min, BD + NOD group, n = 9), dopamine (10 μg/kg/min, BD + Dopamine group, n = 8) or physiological saline vehicle (sham, n = 9 and BD group, n = 9) were administered to the recipient rats. In vivo left-ventricular (LV) graft function was evaluated after 1.5 h reperfusion. Additionally, immunohistochemical detection of 4-hydroxy-2-nonenal (HNE, an indicator of oxidative stress) and nitrotyrosine (a nitro-oxidative stress marker), was performed. After heart transplantation, systolic and diastolic functions were significantly decreased in the BD group compared to sham. Treatment with NOD but not dopamine, resulted in better LV graft systolic functional recovery (LV systolic pressure BD + NOD 90 ± 8 vs BD + Dopamine 66 ± 5 vs BD 65 ± 4 mmHg; maximum rate of rise of LV pressure dP/dt max BD + NOD 2686 ± 225 vs BD + Dopamine 2243 ± 70 vs BD 1999 ± 147 mmHg/s, at an intraventricular volume of 140 μl, p < 0.05) and myocardial work compared to BD group. The re-beating time (time to restoration of heartbeat) was significantly shorter in BD + NOD group than that of BD hearts (32 ± 4 s vs. 48 ± 6 s, p < 0.05), Dopamine treatment had no impact on all of these parameters. Furthermore, NOD as well as dopamine decreased HNE and nitrotyrosine immunoreactivity to the same level. NOD is superior to dopamine in terms of protecting LV graft contractile function when administered to the heart transplant recipients from BD donors., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Background: Recent evidences suggest that sex hormones may be involved in the regulation of exercise-induced left ventricular (LV) hypertrophy. However, the sex-specific functional consequences of exercise-induced myocardial hypertrophy is still not investigated in detail. We aimed at understanding the sex-specific functional and morphological alterations in the LV and the underlying molecular changes in a rat model of athlete's heart. Methods: We divided our young, adult male and female rats into control and exercised groups. Athlete's heart was induced by a 12-week long swim training. Following the training period, we assessed LV hypertrophy with echocardiography, while pressure-volume analysis was performed to investigate in vivo LV function. After in vivo experiments, molecular biological studies and histological investigations were performed. Results: Echocardiography and post-mortem measured heart weight data indicated LV hypertrophy in both genders, nevertheless it was more pronounced in females. Despite the more significant relative hypertrophy in females, characteristic functional parameters did not show notable differences between the genders. LV pressure-volume analysis showed increased stroke volume, improved contractility and stroke work and unaltered LV stiffness in both male and female exercised rats, while active relaxation was ameliorated solely in male animals. The induction of Akt signaling was more significant in females compared to males. There was also a characteristic difference in the mitogen-activated protein kinase pathway as suppressed phosphorylation of p44/42 MAPK (Erk) and mTOR was observed in female exercised rats, but not in male ones. Myosin heavy chain α (MHC)/β-MHC ratio did not differ in males, but increased markedly in females. Conclusion: Our results confirm that there is a more pronounced exercise-induced LV hypertrophy in females as compared to the males, however, there are only minor differences regarding LV function. There are characteristic molecular differences between male and female animals, that can explain different degrees of LV hypertrophy.

Objective: Pressure overload-induced left ventricular myocardial hypertrophy (LVH) regresses after pressure unloading. However, distinct structural alterations become less reversible during the progression of LVH, which might influence the restoration of cardiac function. Here, we investigated how a reverse remodeling process from early versus late-stage LVH affects different aspects of left ventricular function., Methods: Pressure overload was induced in rats for 6, 12 and 18 weeks. Sham-operated animals were used as controls. Pressure unloading was evoked by removing the aortic constriction at week 6 (early-debanded) and week 12 (late-debanded). Echocardiography and histological analyses were carried out to detect structural alterations. Pressure-volume analysis was performed to assess left ventricular function. Molecular alterations were analyzed by quantitative real-time-PCR, and western blot., Results: Myocardial hypertrophy regressed to a similar degree in early and late-debanded groups. Accordingly, no differences were detected in the extent of regression regarding left ventricular mass, cardiomyocyte diameter, heart weight-to-tibial length ratio and beta-to-alpha myosin heavy chain expression. In contrast, resorption of interstitial and perivascular myocardial fibrosis was only detected in the early-debanded group, whereas it persisted in the late-debanded group. Removing the aortic constriction normalized ventriculo-arterial coupling and increased systolic performance in both debanded groups. However, the residual dysfunction in active relaxation and passive stiffness was more severe in the late-debanded compared to the early-debanded group., Conclusion: Early debanding led to complete structural reverse remodeling (reduced hypertrophy and fibrosis) and full restoration of left ventricular function. In contrast, myocardial fibrosis persisted after late debanding, which impeded the normalization of diastolic but not systolic function.

Background: The sodium-glucose cotransporter-2 (SGLT2) inhibitor canagliflozin has been shown to reduce major cardiovascular events in type 2 diabetic patients, with a pronounced decrease in hospitalization for heart failure (HF) especially in those with HF at baseline. These might indicate a potent direct cardioprotective effect, which is currently incompletely understood. We sought to characterize the cardiovascular effects of acute canagliflozin treatment in healthy and infarcted rat hearts., Methods: Non-diabetic male rats were subjected to sham operation or coronary artery occlusion for 30 min, followed by 120 min reperfusion in vivo. Vehicle or canagliflozin (3 µg/kg bodyweight) was administered as an intravenous bolus 5 min after the onset of ischemia. Rats underwent either infarct size determination with serum troponin-T measurement, or functional assessment using left ventricular (LV) pressure-volume analysis. Protein, mRNA expressions, and 4-hydroxynonenal (HNE) content of myocardial samples from sham-operated and infarcted rats were investigated. In vitro organ bath experiments with aortic rings from healthy rats were performed to characterize a possible effect of canagliflozin on vascular function., Results: Acute treatment with canagliflozin significantly reduced myocardial infarct size compared to vehicle (42.5 ± 2.9% vs. 59.3 ± 4.2%, P = 0.006), as well as serum troponin-T levels. Canagliflozin therapy alleviated LV systolic and diastolic dysfunction following myocardial ischemia-reperfusion injury (IRI), and preserved LV mechanoenergetics. Western blot analysis revealed an increased phosphorylation of adenosine monophosphate-activated protein kinase (AMPK) and endothelial nitric-oxide synthase (eNOS), which were not disease-specific effects. Canagliflozin elevated the phosphorylation of Akt only in infarcted hearts. Furthermore, canagliflozin reduced the expression of apoptotic markers (Bax/Bcl-2 ratio) and that of genes related to myocardial nitro-oxidative stress. In addition, treated hearts showed significantly lower HNE positivity. Organ bath experiments with aortic rings revealed that preincubation with canagliflozin significantly enhanced endothelium-dependent vasodilation in vitro, which might explain the slight LV afterload reducing effect of canagliflozin in healthy rats in vivo., Conclusions: Acute intravenous administration of canagliflozin after the onset of ischemia protects against myocardial IRI. The medication enhances endothelium dependent vasodilation independently of antidiabetic action. These findings might further contribute to our understanding of the cardiovascular protective effects of canagliflozin reported in clinical trials.

Aim: Here we aimed at investigating the relation between left ventricular (LV) contractility and myofilament function during the development and progression of pressure overload (PO)-induced LV myocardial hypertrophy (LVH)., Methods: Abdominal aortic banding (AB) was performed to induce PO in rats for 6, 12 and 18 weeks. Sham operated animals served as controls. Structural and molecular alterations were investigated by serial echocardiography, histology, quantitative real-time PCR and western blot. LV function was assessed by pressure-volume analysis. Force measurement was carried out in permeabilized cardiomyocytes., Results: AB resulted in the development of pathological LVH as indicated by increased heart weight-to-tibial length ratio, LV mass index, cardiomyocyte diameter and fetal gene expression. These alterations were already present at early stage of LVH (AB-week6). Furthermore, at more advanced stages (AB-week12, AB-week18), myocardial fibrosis and chamber dilatation were also observed. From a hemodynamic point of view, the AB-wk6 group was associated with increased LV contractility, maintained ventriculo-arterial coupling (VAC) and preserved systolic function. In the same experimental group, increased myofilament Ca 2+ sensitivity (pCa 50 ) and hyperphosphorylation of cardiac troponin-I (cTnI) at Threonine-144 was detected. In contrast, in the AB-wk12 and AB-wk18 groups, the initial augmentation of LV contractility, as well as the increased myofilament Ca 2+ sensitivity and cTnI (Threonine-144) hyperphosphorylation diminished, leading to impaired VAC and reduced systolic performance. Strong correlation was found between LV contractility parameters and myofilament Ca 2+ -sensitivity among the study groups., Conclusion: Changes in myofilament Ca 2+ sensitivity might underlie the alterations in LV contractility during the development and progression of PO-induced LVH., (Copyright © 2019 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Heart transplantation is the definitive treatment for end-stage heart failure. A shortage of donor hearts forced transplant programs to accept older donors and longer ischemic times. Previous studies have suggested that administration of mesenchymal stem cells (MSCs) or their conditioned medium (CM) protects the heart against ischemia/reperfusion injury (IRI). We hypothesized that the preservation of donor hearts with a CM would protect the graft from IRI after prolonged storage in 15-month-old rats and investigated mRNA changes attributable to CM., Methods: Rat MSCs were isolated and cultured. The CM was used and characterized by a 90-antibody array, revealing the presence of 28 factors involved in apoptosis, inflammation, and oxidative stress. Hearts from 15-month-old donor rats were explanted and continuously perfused for 5 hours with oxygenated, 4°C cardioplegic solution, and supplemented with either regular cell culture medium (control group) or CM. The hearts were then heterotopically transplanted. We evaluated in-vivo left ventricular graft function 1.5 hours after transplantation and the myocardial expression of 120 genes using polymerase chain reaction arrays., Results: Systolic contractility and relaxation parameters were significantly reduced in 15-month-old rats compared with the young rats. After transplantation, systolic function (dP/dt max : 1,197 ± 94 vs 1,825 ± 279 mm Hg/s at 140 µl; p < 0.05) and diastolic function (dP/dt min : 737 ± 168 vs 1,200 ± 166 mm Hg/s at 140 µl, p < 0.05) were significantly improved in the CM group compared with controls. Among the genes surveyed, the expressions of 66 were altered. Genes of pro-inflammatory cytokines and interleukins were down-regulated, whereas expression of the anti-oxidant gene superoxide dismutase-2 was up-regulated in the CM-treated grafts compared with the control group grafts., Conclusions: Perfusion of donor hearts with CM protects against myocardial IRI in 15-month-old rats., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Background: Although exercise-induced cardiac hypertrophy has been intensively investigated, its development and regression dynamics have not been comprehensively described. In the current study, we aimed to characterize the effects of regular exercise training and detraining on left ventricular (LV) morphology and function., Methods: Rats were divided into exercised (n = 12) and control (n = 12) groups. Exercised rats swam 200 min/day for 12 weeks. After completion of the training protocol, rats remained sedentary for 8 weeks (detraining period). Echocardiographic follow-up was performed regularly to obtain LV long- and short-axis recordings for speckle-tracking echocardiography analysis. Global longitudinal and circumferential strain and systolic strain rate were measured. LV pressure-volume analysis was performed using additional groups of rats to obtain haemodynamic data., Results: Echocardiographic examinations showed the development of LV hypertrophy in the exercised group. These differences disappeared during the detraining period. Strain and strain rate values were all increased after the training period, whereas supernormal values rapidly reversed to the control level after training cessation. Load-independent haemodynamic indices, e.g., preload recruitable stroke work, confirmed the exercise-induced systolic improvement and complete regression after detraining., Conclusions and Translational Aspect: Our results provide the first comprehensive data to describe the development and regression dynamics of morphological and functional aspects of physiological hypertrophy in detail. Speckle-tracking echocardiography has been proven to be feasible to follow-up changes induced by exercise training and detraining and might provide an early possibility to differentiate between physiological and pathological conditions., (Copyright © 2018 The Authors. Published by Elsevier B.V. All rights reserved.)