Coarctation Of Aorta Research Articles

High prevalence of coronary artery calcium and aortic calcification in adults with repaired coarctation of the aorta and interrupted aortic arch

Abstract Background There is a high rate of late cardiovascular mortality in patients with repaired coarctation of the aorta (CoA) and interrupted aortic arch (IAA). Coronary artery calcium (CAC) is a marker of cardiovascular disease and there is growing evidence for aortic calcification as a predictor. Recent research in the general population suggests any CAC in males <35 years old and females ≤45 years places them at ≥90th percentile. Aims We aimed (1) to determine the prevalence of CAC, thoracic aorta calcification (TAC), and abdominal aorta calcification (AAC) in patients with CoA or IAA repair, and (2) to compare patients to a control group of Tetralogy of Fallot (TOF) patients, a condition with no known increased risk of atherosclerotic cardiovascular disease. Methods Retrospective cohort study of adult survivors of CoA/IAA repair followed up at an adult congenital heart disease (ACHD) clinic. Patients with at least 1 chest, abdomen, or pelvis computerised tomography (CT) scan for any indication were included. The presence/absence of calcification in the coronary arteries or aorta was assessed qualitatively. Patients on antihypertensive and statin therapy were considered hypertensive and hypercholesterolaemic, respectively. Patients were compared to adult survivors of TOF repair with CT scans for any indication (controls). Results Ninety-three CoA/IAA patients (87% CoA/13% IAA, median age at latest follow-up 34 years) had a total of 169 chest and 37 abdomen/pelvis CTs; 82, 93, and 37 patients had at least 1 CT suitable for CAC, TAC, and AAC review, respectively. CAC was present in 22% (18/82), TAC in 33% (31/93), and AAC in 23% (5/22) of CoA/IAA patients. CAC was present in 12% (18/153) and TAC in 11% (18/158) of TOF patients. CoA/IAA patients were more likely to have CAC and TAC than TOF patients (p=0.04 and p<0.0001; respectively) and be younger at the time of diagnosis (CAC p=0.03, TAC p=0.0001) despite TOF patients being older at time of latest CT scan (p=0.0003) (Table 1). Males aged <35 years and females ≤45 years represented 44% (8/18) of CoA/IAA patients with CAC. CoA/IAA patients with CAC were more likely to be hypertensive and hypercholesterolaemic than those without (78% [14/18] vs 48% [31/64], p=0.03; and 28% [5/18] vs 0% [0/64], p<0.0001; respectively) and was similar for TAC (hypertension p=0.005, hypercholesterolaemia p=0.04) but not AAC. After a mean follow-up of 11±7 years from first ACHD clinic, of the 93 patients, 2 patients died, 5 had coronary artery disease (at least mild stenosis on invasive angiography), 3 had a stroke, and 70% (65/93) were considered hypertensive at latest follow-up. Conclusions There is a high prevalence of CAC, aortic calcification, and hypertension in young adults with repaired CoA/IAA. Coronary and thoracic aortic calcification occurs at a younger age compared to controls. Further studies are warranted to assess the impact of aggressive cardiovascular risk reduction in this high-risk group.

Reverse cardiac remodeling induced by endovascular treatment of coarctation of the aorta

Abstract Background Previously, we have showed the 3-year clinical safety and efficacy of balloon expandable versus self-expandable stents in native coarctation of the aorta (CoA) in a randomized clinical trial (RCT). Very few prospective studies have addressed the changes of echocardiographic parameters in mid to long-term follow up of CoA patients treated endovascularly. Purpose We aimed to demonstrate the improvement of echocardiographic parameters among patients undergoing coarctoplasty with stent based on core laboratory-confirmed baseline and 3-year follow up transthoracic echocardiographic (TTE) images. Methods In the index RCT, adult patients with de novo native CoA were randomized into two groups based on stent types. All randomized patients received the 3-year structural follow-up including aortic CT angiography and TTE. The current prospective cohort substudy, included all patients with available baseline and three-year core laboratory TTEs. Results Of 92 patients initially randomized, 71 participated in the 3-year structural follow up. No baseline core lab images were available in 39 patients, and thus, 32 patients (a median age of 32 (24.8 – 37.5) years, (14 women [43.8%]) were included in this subgroup study. One out of the 32 patients presented with recoarctation which was successfully treated before the 3-year evaluation. Peak systolic gradient and end-systolic velocity of the coarctation stenting site were 17.38 ± 6.55 mmHg and 0.93 ± 0.24 m/s respectively in the 3-year follow-up. Septal E’ and lateral E’ velocities were improved significantly (8.6 ± 1.73 cm/s to 9.35 ± 2 cm/s, P = 0.02 and 12.74 ± 2.96 cm/s to 13.92 ± 2.44 cm/s, P = 0.03, respectively). In addition, septal E/E’ ratio (10.84 ± 2.83 to 9.21 ± 3.17, P = 0.02) and lateral E/E’ ratio (7.39 ± 2.24 to 6.29 ± 1.97, P = 0.02) showed significant improvement. Significant reduction in LV mass [160 (130–203) g to 142 (IQR= 121–172) g, P = 0.001], and septal and posterior LV thicknesses were also demonstrated (0.9 (0.8–1.0) cm to 0.81 (0.77–0.93) cm, P = 0.004) and 0.92 ± 0.14 cm to 0.85 ±0.09 cm, P = 0.01, respectively). Twelve (37.5%) patients had baseline LVH which was normalized in 9 (75%). Lastly, 12 (41.3%) of our population had diastolic dysfunction at baseline study which significantly decreased to 4 (13.7%) in the three-year follow-up evaluation. Conclusion In the present core laboratory-based study, coarctoplasty with stent has favorable effects on diastolic function and LV hypertrophy during midterm follow-up in adult population with de novo native aortic coarctation treated with stent.

Arrhythmia burden in patients with congenital heart disease

Abstract Background The prevalence of congenital heart defects (CHD) is rising. Many patients experience arrhythmias either due to the defect itself or necessary intervention. Sudden onset of arrhythmia poses grave risks such as heart failure, stroke, or cardiac death. Research gaps exist regarding high-risk defects, age susceptibility, and prognostic implications of arrhythmia. Purpose Delineate the burden of arrhythmias in patients with CHD. Methods Patients born in the period 1970-2017 and diagnosed with CHD were identified in Swedish nationwide medical registries. Each patient was matched by birthyear and sex with ten controls from the general population. Cox proportional hazard regression model and Fine-Gray regression model with death as competing risk were used to compute risk (hazard ratio [HR]) and cumulative incidence of arrhythmias (supraventricular and ventricular arrhythmias). Estimates were compared with the matched controls. Follow-up started at time of birth. Results We included 63,559 patients and 583,205 matched controls with median follow-up of 12.8 years. Almost two-thirds of the total CHD population were born after year 2000 and 89% (n=56,564) had a simple lesion (defined as atrial or ventricular septal defect, coarctation of the aorta or malformation of the heart valves). During follow-up, 1,632 events of arrhythmia (90% of supraventricular origin) were registered in the population of patients with CHD, yielding an incidence rate of 16.4 per 10,000 person-years (versus 1.6 in the control population). The cumulative incidence of arrhythmias in the total CHD population was slightly increased during childhood compared with the control population, but rose significantly hereafter, illustrated in Figure 1, yielding an overall risk of 10.5 (CI 95%: 9.8-11.2). Stratified by lesion severity, the risk for arrhythmias was 8.7 (CI 95%: 7.6-8.7) and 30.4 (CI 95%: 26.2-35.2) in patients with simple and complex lesions, respectively. Patients with simple CHD lesions displayed a risk of 7.7 (95% CI: 7.1-8.4) for supraventricular arrhythmias and 11.5 (95% CI: 9.2-14.5) for ventricular arrhythmias. Correspondingly, patients with complex CHD lesions displayed risks of 66.7 (95% CI: 42.7-104.2) and 28.9 (95% CI: 24.8-33.6). Conclusion Arrhythmias, irrespective of origin, are common in patients with CHD and correlate with lesion severity. The overall burden of arrhythmias increased significantly after childhood. Meticulous follow-up is vital in order to prevent, detect and treat arrhythmias as it might trigger clinical deterioration and even sudden cardiac death in patients with CHD.

Late pseudo-aneurysms after coarctation repair with extra-anatomic ascending-descending aortic bypass surgery

Abstract Background Extra-anatomic ascending-descending aortic bypass operations are an alternative to difficult aortic arch reconstruction in patients with complex aortic coarctation. Reported short-term results are favorable, however, data on long-term outcomes are sparse. The aim of our study was to report long-term outcomes in affected adult patients. Methods We identified all adults with extra-anatomic ascending-descending aortic bypass surgeries followed at our center. Outcomes were assessed by chart review with a specific focus on formation of late pseudo-aneurysms and requirement for redo surgery. Results We identified a total of 12 adults (67% males) with previous ascending-descending aortic bypass surgery. These patients account for 12/171 (7%) of adults with aortic coarctation followed at our center. 10/12 patients (83%) had undergone coarctation repair by different repair techniques before ascending-descending aortic bypass surgeries. Median age at ascending-descending aortic bypass surgery was 17 years (range: 7-42 years). Prosthetic conduit sizes ranged from 12-22mm. In long-term follow-up, 11/12 patients (92%) required antihypertensive medication (median 2 antihypertensive drugs, 50% ≥ 3 drugs). A total of 5/12 patients (42%) required redo-surgery for formation of pseudo-aneurysms (figure 1) at graft anastomoses (4 proximal anastomosis at ascending aorta, 1 distal anastomosis to descending aorta) at a median age of 47.6 years (28.2-65.0 years) and a median of 22.1 years (range: 14.7-24.6 years) after the initial extra-anatomic ascending-descending aortic bypass operation (figure 2). Two of these patients required redo-operations / interventions for recurrent pseudo-aneurysms at 26 and 33 months after the redo-operations. Conclusions Although reported short- and medium-term outcomes after ascending-descending aortic bypass surgery for complex aortic coarctation are favorable, our data suggest a high rate of pseudo-aneurysm formation late (>10 years) after surgery. Our data highlight the need for careful long-term (life-long!) follow-up of these patients at specialized centers.

Double arch technique - a novel surgical procedure for the hypoplastic aortic arch syndrome

Abstract Background The hypoplastic aortic arch syndrome was defined as a combination of hypoplastic aortic arch and complex proximal descending aortic anomalies (such as aortic aneurysm, aortic coarctation, aortic tortuosity, or aortic dissection). In this study, we proposed a novel 'double arch' technique as a simple surgical procedure to treat the hypoplastic aortic arch syndrome, which could eliminate the requirement for cardiopulmonary bypass. Purpose This study aimed to investigate the surgical outcomes of patients who underwent the 'double arch' technique, and further evaluate the effectiveness and safety of this novel technique. Methods Briefly, J-shaped mini-sternotomy and left posterolateral thoracotomy were both performed in this technique. The ascending aorta, aortic arch, and proximal descending aorta were dissociated. After that, the ascending aorta was occluded using a side-biting clamp, followed by an end-to-side anastomosis between the proximal end of vascular graft and the ascending aorta. Similarly, the thoracic descending aorta was occluded with two aortic clamps beyond the opening of the left subclavian artery, and was then transected between the clamps, followed by an end-to-end anastomosis between the distal end of vascular graft and the distal descending aorta, while the proximal descending aorta was closed with sutures. The transection site of the aorta could be adjusted according to the extent of the lesions, and the vascular graft was placed in the left thoracic cavity. The operation was performed at room temperature. The primary endpoint was early mortality, which referred to in-hospital death and/or death within 30 days after surgery (including intraoperative death), whichever is longer. Critical secondary endpoints included aortic reoperation, newly developed aneurysms, and the blood pressure difference between the upper and lower extremities. Results Twelve patients with hypoplastic aortic arch syndrome were enrolled from December 2015 to February 2022. Patients were diagnosed using computed tomography. The median age (interquartile range, IQR) was 26.5 (17.0, 39.0) years (ranging from 12.0 to 55.0), and 8 patients were female (66.7%). The median operation time (IQR) was 4.7 (3.8, 5.5) hours (ranging from 2.8 to 7.3). All patients survived to discharge and completed the follow-up. The median follow-up time (IQR) was 5.42 (3.25, 5.97) years (ranging from 0.02 to 6.25). During the follow-up, no patient died or was required for reoperation. In addition, no newly developed aneurysm was found, and no severe adverse event was recorded. The median blood pressure difference (IQR) between the upper and lower extremities was 9 (4, 17) mmHg (ranging from 3 to 27). Conclusions The 'double arch' technique is a viable alternative surgical treatment for the hypoplastic aortic arch syndrome. This technique is expected to significantly simplify the surgical procedure and improve the long-term prognosis of patients.Diagram of the 'double arch' techniqueCT scans of pre- and post-operation

Variability in patient-reported outcomes among different congenital heart defects: a comparative analysis of 7,498 patients from 32 countries

Abstract Background Patient-reported outcomes (PROs) may not always correlate with the complexity of congenital heart defects (CHDs), as significant variation has been observed between CHDs within complexity levels. Accurate comparisons across various types of CHDs necessitate large sample sizes. Purpose The objective of this study was to compare PROs across different CHDs in a large international sample. Methods ‘Assessment of Patterns of Patient-Reported Outcomes in Adults with Congenital Heart disease – International Study II’ (APPROACH-IS II) was an international cross-sectional investigation, in which 8,415 patients from 32 countries in 6 continents were enrolled (20 high; 7 upper-middle; 4 lower-middle; and 1 low income). For the comparison across different CHDs, conditions with at least 50 patients were included in the analysis. Hence, the sample consisted of 7,498 patients (median age=33y; 53.1% women). Patients completed questionnaires to measure perceived health status (RAND-12 Health Survey; EuroQOL-5D Visual Analog Scale); depressive symptoms (Patient Health Questionnaire-8); anxiety (General Anxiety Disorder-7) and quality of life (Linear Analog Scale). Generalized linear mixed models (GLMMs) were performed with center as random effect. Results Cyanotic heart defects were associated with the lowest scores for physical functioning, mental health, self-rated health, and quality of life (see Figure). Other CHDs found to be associated with poor PRO scores encompassed unrepaired secundum atrial septal defect, Ebstein anomaly, single ventricle, and truncus arteriosus. Conversely, the most favorable scores for all PROs, except for anxiety, were observed with isolated pulmonic stenosis. Other CHDs with favorable PRO scores comprised coarctation of the aorta, isolated small ventricular septal defect, congenital aortic valve disease, and repaired ventricular septal defect. Adjusted for sociodemographic and physiological factors, GLMMs revealed significant differences across defects, using the best score for each PRO as the reference (see Figure). Conclusion Substantial variation in PROs was observed among different types of CHDs. Interestingly, some complex heart defects demonstrated relatively good PRO scores, comparable to some simple defects. On the other hand, unrepaired simple defects or those with residual lesions, were associated with worse PROs.

Cardiovascular health in women with turner's syndrome: a 3-year single centre audit

Abstract Background Turner’s syndrome (TS) is the most common genetic abnormality affecting females and is characterised by complete or partial absence of the X chromosome. Mortality is predominantly related to cardiovascular disease (1). Risk of life-threatening aortic dissection is 40 per 100,000 (2). Indexed aorta size (ASI) to body surface area (BSA) >20mm/m² is considered abnormal. An ASI of ≥25mm/m² is associated with increased risk of aortic dissection (3). Despite this there is a paucity of data in the literature regarding TS cardiovascular disease and providing evidence-based care can be challenging. Purpose Define cardiovascular disease, with focus upon aortopathy in our TS Cardiovascular Clinic (TCC). Methods Single centre retrospective medical record analysis of 248 women with TS (2021-2024) Results Patient baseline characteristics; mean age 37 years (range 18-75yrs), height 150cm (132-169cm), weight 62kg (37-130kg), BSA 1.55m² (1.19-2.17m²). 65 patients (29%) had bicuspid aortic valve (BAV), 19 (8%) and 5 (3%) had repaired and un-repaired aortic coarctation (CoA) respectively. 30 (13%) had other congenital heart disease, with most common was partial anomalous pulmonary venous connection (12 patients: 5%). 22/248 patients had previous aortic root surgery; 20 elective (mean ASI 29mm/m², range 26-33mm/m², mean age at time of surgery 42 years); 2 presented with aortic dissection (ASI 21mm/m²; pregnant, BAV & 24mm/m²; tri-leaflet aortic valve, TAV). Data was available for 221 unoperated patients (figure 1). The site of maximal dimension was observed at the sinus of Valsalva in 70% compared to 30% at the ascending aorta. 130 patients (59%) had maximal ASI of <20mm/m². Dimensions of 20-23mm/m² and 23-25mm/m² were seen in 64 (29%) and 18 (8%) patients respectively. 7 patients (3%) had a maximal ASI of >25mm/m². 4 patients (2%) had an absolute maximal dimension of 40mm with ASI of 23mm/m² for all four. 9/11 patients with dimension ≥25mm/m² or 40mm had a body mass index (BMI) >25kg/m². Review of medical history for patients at and above threshold for risk of aortic dissection revealed referral to or previous discussion in an Aortic multi-disciplinary meeting (MDT) with a plan for ongoing surveillance. 57 patients (35%) with TAV had significant aortopathy (mean age 46years, range 19-75years) compared with 33 (51%) with BAV (mean age 39yrs, range 22-72 years) (figure 2). Review of patients >55years of age demonstrated a very similar burden of aortopathy in both TAV (14%) and BAV (15%) populations. Conclusions A high burden of cardiovascular disease exists within our TS population. There is a very high prevalence of aortopathy, increasingly with age and both with and without the presence of a bicuspid aortic valve. More published data is needed to help better define those at risk.

The effect of afterload on right ventricular pacing-induced left ventricular dysfunction: a translational study

Abstract Introduction Right ventricular (RV) pacing (RVP) impairs left ventricular (LV) function. Nevertheless, the interaction between arterial afterload and RVP-associated LV dysfunction has not been investigated yet. Purpose We sought to examine the effect of afterload on RVP-evoked LV hemodynamic changes in patients with aortic stenosis (AS) undergoing transcatheter aortic valve implantation (TAVI) as well as in a small animal model of sustained LV pressure overload (PO). Methods Thirty-five patients with AS and a previously implanted pacemaker underwent detailed echocardiographic examination immediately before TAVI and also on the second postoperative day. The ultrasound measurements were carried out during intrinsic, narrow QRS rhythm and during frequency-matched RVP as well. Global myocardial work index (GMWI) was calculated to assess LV contractility. In parallel, LV pressure-volume analysis was performed in Wistar rats with transverse aortic constriction (TAC) or sham operation (Sham) during intrinsic narrow QRS rhythm (termed as TAC-Vsense and Sham-Vsense) as well as during RVP (termed as TAC-Vpace and Sham-Vpace). RVP was achieved in rats by an octopolar electrophysiology catheter placed in the RV. Results RVP decreased LV contractility in AS patients before and after TAVI as well. Nevertheless, the extent of RVP-evoked LV dysfunction was alleviated following pressure unloading (ΔGMWI: -37±7 vs. -25±8%, before TAVI vs. after TAVI, P<0.05). Similarly, although RVP was associated with reduced LV contractility in both the TAC (the slope of the maximum rate of LV pressure rise-end-diastolic volume relation [dPdtmax-EDV]: 92±8 vs. 53±6mmHg/s/µl, TAC-Vsense vs. TAC-Vpace; P<0.05) and Sham groups (dPdtmax-EDV: 74±5 vs. 60±9 mmHg/s/µl, Sham-Vsense vs. Sham-Vpace; P<0.05), the negative inotropic effect of RVP was found to be stronger in the TAC compared to the Sham group (ΔdPdtmax-EDV: -42±4 vs. -19±6%; TAC vs. Sham, P<0.01). Furthermore, reduction of the maximal rate of LV pressure decrease (ΔdPdtmin: -20±3 vs. -5±5%, TAC vs. Sham, P<0.01) and prolongation of the active relaxation time constant (Δτ: 22±3 vs. 6±3%, TAC vs. Sham, P<0.01) also occurred to a greater extent in case of sustained LV PO, indicating augmented diastolic dysfunction. Conclusion Our translational results indicate that RVP-induced LV dysfunction might be afterload dependent.

Temporal dynamics of cardiac remodelling in pressure overload: the key role of visceral adipose tissue

Abstract Background Myocardial fibrosis is a prominent pathological feature of cardiac remodelling in pressure overload. The underlying mechanisms of cardiac remodelling are complex including mechanical, inflammatory and neurohormonal factors. We have recently uncovered a pathological crosstalk between visceral adipose tissue (VAT) and heart in biological aging characterized by profibrotic proteins in both the VAT secretome and the plasma contributing to myocardial interstitial fibrosis. We hypothesize that a model of pressure overload induced by transverse aortic constriction (TAC) is responsible for VAT remodelling and a VAT profibrotic secretome, which in turn worsens cardiac fibrosis and alters cardiac function. Purpose To explore the effect of pressure overload on VAT and identify a crosstalk between heart and VAT. Methods We divided wild-type male mice (5-month-old, n=10/group) into two groups: a visceral Lipectomy group and a Sham group two weeks before a moderate TAC (26G; i.e. gradient between left ventricle and aorta of 30mmHg) or a sham surgery. We sacrificed the mice at 1- and 8-week after TAC. We performed in vivo metabolic tests, echocardiography, and invasive hemodynamics, followed by ex vivo tissue analysis. We then analysed the time-course of the cardiac transcriptomic signature in TAC vs control and the impact of visceral lipectomy in both groups. Results Our results show that TAC induced not only cardiac remodelling affecting the structure and function of the heart, but also VAT fibrosis and inflammation together with activation of adrenergic receptors (Adrb3). VAT became a major source of profibrotic (TGFb and osteopontin) and proinflammatory (TNFa, IL6 and PAI1) factors as early as 1 week after TAC. Interestingly, lipectomy prevented cardiac remodelling and dysfunction. After 1 week of TAC, cardiac transcriptomic profile showed a similar upregulation of profibrotic and prohypertrophic genes in TAC groups in presence or absence of lipectomy. After 8 weeks of TAC, lipectomy prevented the upregulation of those genes and transcriptomic profile of TAC+lipectomy was similar to sham group (Figure). PCR analysis confirmed the lower expression of profibrotic (TGFb, Osteopontin), prohypertrophic (Nppa) and contractility genes (Adr1b) in TAC+Lipectomy vs TAC group after 8 weeks of TAC. Conclusion Our results suggest that VAT is detrimental to cardiac structure and function by releasing a profibrotic and a proinflammatory secretome that aggravates the cardiac remodelling induced by TAC. Conversely, lipectomy prevents the early development of TAC-induced cardiac fibrosis.

ATM: a protein involved in glucose and lipid metabolism in the heart

Abstract Backround Post-mitotic cells, such as neurons and cardiomyocytes, cannot repair DNA lesions with DNA replication and rely for their survival on efficient sensors and effectors that orchestrate the DNA damage response (DDR). The Ataxia Telangiectasia Mutated (ATM) protein kinase is the most important sensor of oxidative stress and the DNA damage response (DDR) and is implicated in cellular metabolism. It is believed that while transient DNA damage and DDR can temporarily improve cardiovascular function, persistent activation of DDR (and ATM) might promote the onset and development of heart failure (HF). Purpose We hypothesised that ATM might control and regulate energy metabolism in the heart under stress to promote DNA repair. Methods We analyzed the effects of ATM inactivation on cardiomyocyte hypertrophy, cardiac function, DDR and metabolism in hearts from wild-type (Atm+/+) or Atm-mutated (Atm-/-) mice under sham conditions or after pressure overload by transverse aortic constriction (TAC). Results ATM inactivation in Atm-/- mice induced cardiomyocyte hypertrophy, fetal gene expression re-activation and a specific metabolomic signature in the heart, characterized by significant accumulation of pyruvate, branched chain amino-acids, short-medium acyl-carnitines and metabolites of tricarboxylic acid cycle. The levels of the glycolytic enzymes, hexokinase-2 (HK2) and phosphofructokinase (PFK), were elevated. pyruvate was trapped in the cytosol because mitochondrial carriers were suppressed and the enzymes that process pyruvate were dysregulated. Because of pyruvate metabolic block, fatty acids oxidation was inefficient and resulted in the accumulation of acyl-carnitines and insulin resistance. These metabolic changes were amplified by TAC, which rapidly induced heart failure in Atm-/- mice. ATM inactivation also increased basal and TAC-induced genomic stress in cardiomyocytes, as shown by the levels of p-γ-H2AX, 8-oxodG glycosylase (OGG1/2) and apurinic site nuclease (APE1). These results prove that ATM rewires the metabolism of cardiac cells by inducing glycolysis and fatty acids oxidation. ATM stimulates glycolysis to repair DNA lesions and protect the heart against stress-induced dysfunction. The metabolic block due to ATM inactivation accelerates heart failure. Conclusions Our data suggest that ATM favors the metabolic flexibility of the heart by stimulating glucose entry and balancing glucose catabolism with fatty acid oxidation, thus preventing mechanical stress-induced cardiac systolic dysfunction.

Deletion of mitochondrial DNA methyltransferase 1 contributes the development of murine heart failure under pressure overloaded

Abstract Background Mitochondrial DNA (mitDNA) has similarities to bacterial DNA, which contains inflammatogenic unmethylated CpG motifs. We found that mitDNA that escapes from autophagy causes inflammatory response and heart failure under pressure overload. DNA methyltransferase 1 (DNMT1) maintains methylation patterns in somatic cells. Deletion of DNMT1 results in embryonic lethality in mice and mitotic catastrophe in cultured cells. Additional possible translational start sites (ATG1, ATG2) are located upstream of the commonly accepted nuclear DNMT1 translational start site (ATG3) and there is a conserved mitochondrial translocation signal sequence between ATG1 and ATG3. The role of mitochondrial DNMT1 in the development of heart failure remains to be elucidated. Purpose The purpose of this study is to examine the in vivo role of mitochondrial DNMT1 in the heart under pressure overload. Methods We generated HA-tagged DNMT1 constructs, 1) starting from ATG1 (termed as whole) 2) from ATG3 (nuclear) and 3) from ATG3 and mutated in the nuclear translocation sequence (mitochondrial) and transfected HEK293 cells with the constructs. Localization of HA-tagged proteins was assessed by immunocytochemistry. We also generated mitochondrial DNMT1-deficient mice by inserting mutations into the ATG1 and ATG2. The mice were subjected to pressure overload by means of transverse aortic constriction (TAC) to induce heart failure. Cardiac remodelling was assessed by echocardiography as well as histological analyses 4 weeks after operation. Results Whole, nuclear and mitochondrial DMNT1 translocated to both mitochondria and nuclei, only nucleus and only mitochondria, respectively. Mitochondrial DNMT1-deficient mice were born at Mendelian frequency and grew to adulthood. Those showed no cardiac phenotypes under baseline conditions. However, the mice exhibited severe systolic dysfunction, indicated by left ventricular fractional shortening, 2 weeks after surgery compared with control littermates (control littermates 47.9% versus Mitochondrial DNMT1-deficient mice 32.3%, p<0.05). Intermuscular cell infiltration was observed in TAC-operated mitochondrial DNMT1-deficient hearts. Conclusions Mitochondrial DNA methyltransferase 1 plays a protective role in failing hearts and mitDNA methylation might be a therapeutic target to treat patients with heart failure.

SNORD3A: a new possible circulating biomarker of human heart failure

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

HECT domain containing-3 (HECTD3) E3 ubiquitin ligase attenuates cardiac ischemia and hypertrophy in mice

Abstract HECT domain containing 3 (HECTD3) is one of the E3 ubiquitin ligases, the cardiac function of which is not completely understood yet. We aimed here to understand the role of HECTD3 in cardiomyocytes using loss- and gain-of-function approaches in in vitro and in vivo models. Interestingly, we found that HECTD3 was significantly downregulated in cardiac tissue obtained from human patients suffering from cardiac hypertrophy and ischemia. We thus employed loss- and gain-of-function approaches in neonatal rat cardiomyocytes (NRVCMs) to get further insights into potential cardiac function of HECTD3. Overexpression of HECTD3 in NRVCMs attenuated cardiomyocyte hypertrophy and lipopolysaccharide (LPS) or interferon-γ (IFN- γ) induced cellular inflammation; its knockdown on the other hand aggravated these effects. Mechanistically, using Yeast two-hybrid screen, mass-spectrometry, and transcriptomics analyses, we identified Small Ubiquitin like Modifier 2 (SUMO2) Signal Transducer and Activator of Transcription-1 (STAT1) as novel substrates for HECTD3, regulation of which resulted into attenuation of hypertrophy and inflammation, respectively. To translate these in vitro results in vivo, we employed Adeno-associated virus-9 (AAV-9) mediated gene therapy approach to overexpress HECTD3 specifically in the heart of mouse models of cardiac ischemia due to permanent ligation of the left anterior descending artery (LAD), and cardiac hypertrophy due to transverse aortic constriction (TAC). Overexpression of HECTD3 in mice, though moderate but significantly improved cardiac function upon ischemic or hypertrophic stress compared to respective control groups. Importantly, in vitro findings were consistent in vivo, where AAV-9 mediated overexpression of HECTD3 substantially reduced cardiac hypertrophy and fibrosis, improved cardiac function as assessed by echocardiography, inhibited activation of STAT1-mediated downstream signaling, and attenuated infiltration of inflammatory cells to the heart after TAC or LAD ligation. This data indicates that HECTD3 is a novel modulator of cardiac ischemia, hypertrophy, and inflammation via regulation of SUMO2 and STAT1-signaling. In conclusion, we report here a novel cardioprotective mechanism involving the E3 ubiquitin ligase HECTD3, which exerts anti-hypertrophic and anti-inflammatory effects via dual regulation of SUMO2 and its SUMOylating target STAT1. We believe that this "dual pathway" inhibition exhibits translational importance and could further be exploited for the prevention and/or therapy of heart failure due to cardiac ischemia or hypertrophy.

Integrating single-cell sequencing and genetic lineage tracing reveals endothelial plasticity during atrial remodeling

Abstract Background Atrial fibrillation (AF), as the most burdensome cardiac arrhythmia, could lead to the significant mortality and morbidity. Atrial fibrosis is a well-recognized pathophysiological factor of the development and progression of AF, which also hampers its treatment. However, the underlying mechanisms of this intricate process remain largely unknown. Purpose This study sought to reveal the cellular composition of AF substrate and investigate the vital contributors to atrial structural remodeling. Methods Left atrial appendages from three patients with AF undergoing surgical ablation and three individuals with sinus rhythm undergoing heart transplantation were subjected to 10X single-cell RNA sequencing (scRNA-seq). Another five public scRNA-seq or snRNA-seq datasets of potentially remodeled right or left appendages were retrieved across three publications. The vital contributors of atrial structural remodeling and their characteristics were identified by intercellular communication analysis and trajectory inference. Transverse aortic constriction (TAC) was used to induce atrial remodeling in Cdh5-CreERT2;RFP mice, followed by scRNA-seq of endothelial cells (ECs). Human primary atrial ECs and fibroblasts were isolated for cell-cell interaction experiments. ECs-specific mouse models of Transforming growth factor beta 1 (TGFB1) (knockout and overexpression) were generated. Electrophysiological and histology analyses were performed to determine the consequences of ECs-derived TGFB1 gain and loss of function in the atrium. Results The comprehensive analysis of different scRNA-seq datasets revealed that ECs played an important regulatory role in the homeostasis of atrial substrate and displayed remarkable mesenchymal activation during atrial remodeling, which was further confirmed by TAC mice. Immunofluorescence staining and high-content screening suggested that the complete transition from ECs to mesenchymal cells slightly contributed to atrial remodeling. However, TGFB1 secreted from mesenchymal activated ECs significantly promoted activation, proliferation, and collagen secretion of fibroblasts. We discovered that overexpression of TGFB1 in ECs of mice significantly increased atrial fibrosis, and thus prolonging AF duration. Besides, knockout of TGFB1 in ECs of mice underwent TAC significantly attenuated the atrial fibrosis and decreased the rate of AF. Conclusion Our work demonstrates that mesenchymal ECs-derived Tgfb1 plays an important role in atrial remodeling by regulating the fibroblast function. EC-specific interventions were suggested to facilitate the development of novel strategies for mitigating AF substrate remodeling.

Deletion of nephrocystin 4 exacerbates cardiac function and survival rate in a mouse model of cardio-renal syndrome

Abstract Background Cardiorenal syndrome (CRS), characterized by cardiac and renal dysfunction, is an increasing health problem associated with high mortality rate. Nephrocystin 4 (NPHP4) gene is the major cause of end-stage renal disease in children. We have reported NPHP4 single nucleotide polymorphism is the genetic risk for CRS and subsequent cardiovascular events in general population. However, the functional role of Nphp4 in the development of CRS has never been examined yet. Methods and Results We generated systemic Nphp4 knockout (KO) mice deleting exon 3 to 8 using CRISPR-Cas9 system. RNA sequence analysis of heart and kidney tissues demonstrated that gene-sets related to mitochondrial function were significantly downregulated in Nphp4 KO mice compared to their wild-type (WT) littermates. Nphp4 KO mice showed less cardiac hypertrophy, however, exacerbated cardiac function and survival compared to WT mice in a CRS model induced by thoracic transverse aortic constriction. Nphp4 located in endosome and cell membrane in H9C2 cardiomyocytes. Immunoprecipitation confirmed protein interaction between Nphp4 and HECT-type E3 ligase Itch. Furthermore, we found that Itch targeted Lats2 and insulin-like growth factor-1 receptor in cardiomyocytes. Knockdown of Nphp4 activated Hippo signaling and worsened mitochondrial function in H9C2 cardiomyocytes through the inhibition of Itch-dependent Lats2 degradation. Knockdown of Nphp4 inhibited insulin-like growth factor-1 signaling through the disturbance of Itch-mediated endosome function. Conclusions Deletion of Nphp4 impaired compensatory cardiac hypertrophy and exacerbated cardiac function and survival in a mouse CRS model through mitochondrial dysfunction. Nphp4 mediated Hippo signaling and insulin-like growth factor-1 signaling through the interaction with Itch. NPHP4 could be the novel therapeutic target in CRS.figure1figure2

Cardiac secreted-HSP90alpha in cardiomyocyte hypertrophy by N-Cadherin mediated signaling under pressure overload

Abstract Background Left ventricular hypertrophy (LVH) in response to pressure overload is strongly associated with adverse cardiovascular outcomes. Heat shock protein 90 (HSP90) has been reported to be involved in cardiac remodeling under stress. Aims Here, we evaluate whether serum HSP90α (an isoform of HSP90) increases and associates with cardiac hypertrophy in patients with hypertension or severe aortic stenosis (AS), and explore the potential mechanisms in experimental pressure overload mouse model. Methods Serum HSP90α levels in patients with hypertension or aortic stenosis (AS) were determined by ELISA. Pressure overload mouse model was built by a transverse aortic constriction (TAC). Cardiac function was assessed by echocardiography. Cardiac hypertrophy was examined by histology, western blot and RNA analysis. Results Serum levels of HSP90α were higher in patients with hypertension or AS than in the control group, respectively, and the levels positively correlated with LVH. HSP90α levels also increased in heart tissues of patients with obstructive hypertrophic cardiomyopathy (HCM), and mice after TAC, in parallel with the hypertrophic markers. TAC induced the enhanced expression and secretion of HSP90α from cardiomyocytes and cardiac fibroblasts. Knockdown of HSP90α or blockade of extracellular HSP90α (eHSP90α) prevent the development of LVH under pressure overload in vivo and in vitro. By Nano-HPLC-MS/MS analysis, we identified eHSP90α interacted with N-cadherin in cardiomyocyte surface, which induced the activation of β-catenin and promoted β-catenin to bind TCF7 (a member of TCF/Lef family) in nucleus, enhanced the transcription of hypertrophic genes, contributing to cardiac hypertrophy and dysfunction under pressure overload. Conclusions Our data demonstrated that cardiac secreted-HSP90α promoted myocardial hypertrophy by N-Cadherin mediated β-catenin/TCF7 signaling under pressure overload. It indicates the therapeutic potential of targeting HSP90α-initiated signaling against cardiac hypertrophy and dysfunction under pressure overload.

Effects of empagliflozin on cardio-renal interaction in heart failure with reduced ejection fraction: results from in-vivo experiments and the CINNAMON-study

Abstract Background Heart failure is often accompanied by renal dysfunction, which indicates a pathophysiological connection between the heart and kidneys. Empagliflozin, a SGLT2 inhibitor, showed beneficial effects on both cardiovascular and renal endpoints. Mechanistically, however, it is unclear whether the empagliflozin-dependent renal protection is mediated via the inhibition of renal SGLT2 or rather indirectly via improved cardiac function. Interestingly, in the EMPEROR trials, there was a significant interaction of empagliflozin-dependent kidney protection with systolic contractile dysfunction. We hypothesized that Empagliflozin treatment ameliorates heart failure in response to chronic pressure overload in mice leading to improved renal function. We correlated these findings with data from our prospective, single-armed trial. Methods Transverse aortic constriction (TAC) or sham surgery was performed in C57BL/6J (wildtype, WT) and SGLT2 deficient mice (SGLT2-/-). Animals received either Empagliflozin (10 mg/kg bodyweight) or vehicle by daily oral gavage. Cardiac function was evaluated by echocardiography and kidney function by transdermal FITC-Sinistrin measurement (GFR), urinary albumin/creatinine ratio (UACR) and Siriusred fibrosis staining. Results After 10 weeks, echocardiography confirmed TAC induced pressure-overload, leading to reduced left ventricular ejection fraction (LVEF) and diastolic dysfunction. Empagliflozin attenuated changes in LVEF (Fig. A) and improved diastolic dysfunction (data not shown). Interestingly, at 10 weeks, TAC reduced GFR, increased UACR and tended to increase renal fibrosis, which was attenuated by empagliflozin (Fig. B, C and D). To test if direct inhibition of SGLT2 in the heart and kidney is mechanistically involved, TAC surgery was repeated in SGLT2-deficient mice (SGLT2-/-). In fact, exposure to TAC resulted in comparable reduction of LVEF in SGLT2-/- mice and Empagliflozin prevented this deterioration similar to WT mice (Fig. E vs. A). Surprisingly, Empagliflozin also prevented GFR deterioration 10 weeks after TAC in mice lacking SGLT2 (SGLT2-/-) with comparable magnitude as in WT mice (Fig. F), suggesting that the reno-protective effect of Empagliflozin was independent from renal SGLT2 inhibition. The effect of empagliflozin on the heart and kidney was also investigated in patients with HF (prospective, single-arm CINNAMON-study, DRKS00031101). After 180 days of Empagliflozin treatment (10 mg), there was a significant improvement in LVEF, NT-proBNP levels and KCCQ-12 Scores (Fig. G-I) and the effects on UACR and GFR are subject of investigation. Conclusion This is the first study investigating the role of SGLT2 in Empagliflozin-dependent kidney protection of mice that develop heart failure after TAC. Importantly, empagliflozin treatment prevented deterioration of LVEF and GFR independent of the presence of SGLT2 in mice and improved cardiac markers and quality of life in patients.

Vaccination targeting senescence-associated transmembrane protein alleviated cardiovascular pathology in the mice

Abstract Introduction Accumulation of senescent cells is observed in various organs including vasculature, heart and white adipose tissue with age, and known to become a substrate of pathophysiology of various cardiovascular-metabolic diseases. We have previously developed a vaccine to eliminate senescent cells, so-called "senolytic vaccine" by targeting Glycoprotein Nonmetastatic Melanoma Protein B (GPNMB) as a cellular-senescence-associated cell surface protein. We have demonstrated that GPNMB senolytic vaccine could remove senescent cells and alleviate the pathology cardiovascular-metabolic diseases. Senescence-associated adhesion molecule 1 (SAAM-1) is also known as a cell-surface membrane to increase its expression during cellular senescence in endothelial cells as well as the development of cardiovascular diseases. Here, we identified SAAM-1 as another senescence antigen and created a vaccine to eliminate senescent cells by targeting SAAM-1. Purpose This study was purposed to evaluate the efficacy of SAAM-1 vaccine for the treatment of cardiovascular diseases in mice models. Methods As a pressure overload-induced heart failure (HF) model, C57BL/6N wild type (WT) mice were underwent transverse aortic constriction (TAC) or sham opretaion at 13 weeks of age. SAAM-1 or control vaccination were given at 8 and 10 weeks of age before operation. Echocardiography examination was conducted two weeks after TAC operation, followed by tissue sampling 3 weeks after the examination. As an atherosclerosis model, ApoE KO mice were subjected to a high-fat diet (HFD) starting at 4 weeks of age. Vaccination of ApoE KO mice was administered at 8 weeks of age with SAAM-1-vaccine or control-vaccine, followed by sacrifice 4 weeks later for further analysis. ApoE-KO mice were also crossed with p16-mediated Luciferase expressing mice (p16-Luc mice) and subjected to generation of atherosclerosis model. Results SAAM-1 expression was significantly increased in left ventricle (LV) in TAC mice but its increase was suppressed by SAAM-1 vaccination. Interestingly, both worsening systolic function and dilatation of LV by pressure overload were significantly alleviated by SAAM-1 vaccination. Furthermore, expression level of senescent markers including p16 and p21, as well as several inflammation markers were increased in failing heart along with development of cardiac fibrosis, but SAAM-1 vaccine could significantly attenuate this pathological change. In ApoE KO mice, SAAM-1 vaccine decreased expression level of several inflammation markers in the mice, along with a decreasing p16 signal in the aorta. Conclusions Targeting SAAM-1 for vaccination would be a novel and promising approach to alleviating age-related cardiovascular disease.

Inhibiting chondroitin sulfate synthase 1 ameliorates hyperplastic arterial remodelling

Abstract Introduction Hyperplastic arterial remodelling is characterized by intima-media thickening, lumen narrowing, inflammation and increased extracellular matrix (ECM) deposition. Chondroitin sulfate (CS) glycosaminoglycans, the unbranched polysaccharide chains of proteoglycans, are important components of ECM. We previously found CS accumulated in adversely remodelled heart and artery, aggravating cardiac deterioration. Objective We aim to explore a therapeutic strategy to interfere with CS synthesis and investigate its potential in ameliorating hyperplastic arterial remodelling. Methods Through single-cell RNA sequencing of non-cardiomyocytes cardiac cells from mouse myocardial infarction model, chondroitin sulfate synthase 1 (CHSY1) was identified as the primary CS synthase and was increased during disease progression. A Chsy1 knockout (KO) mouse strain was generated. Fibrosis and arterial remodelling were induced using: (i) 4 weeks of angiotensin II/phenylephrine (AngII/PE) infusion through subcutaneous osmotic minipumps; and (ii) transverse aortic constriction surgery. To assess the therapeutic potential of CHSY1 inhibition in ameliorating hyperplastic arterial remodelling, Chsy1 was knockdown by dsiRNA post disease onset. Mechanism of action was investigated using primary vascular smooth muscle cells (VSMCs). Results Chsy1 KO reduced CS and its stereoisomer dermatan sulfate in the heart to 42 ± 22% and 36 ± 7% respectively, whereas other types of glycosaminoglycans remain intact. KO mice were protected against phenotypes of hyperplastic arterial remodelling induced by the two disease models in both the coronary and carotid arteries. For example, 90.1% of coronary arterial fibrosis and 79.7% of macrophage infiltration induced by AngII/PE was declined in KO mice compared to WT mice, while cardiac function as stroke volume was augmented by 41.3%. Concomitantly, carotid arterial wall thickening was lower by 36.5% and distensibility was higher by 36.7%, validating Chsy1 as a potent target. As a therapeutic approach, weekly intravenous injection of dsiRNA achieved Chsy1 reduced to 30.2 ± 5.5% in the carotid artery and 72.5 ± 4.7% in the heart. Post disease onset, Chsy1 KD therapy reduced fibrosis by 59.9% in the coronary artery (P = 0.006) and improved stroke volume by 25.6% (P = 0.036). The structural integrity and function of carotid arteries were well-reserved, manifesting as improved distensibility (29%, P = 0.016), increased elastin/perimeter ratio (15%, P = 0.002), and reduced macrophage infiltration (38%, P = 0.029). In vitro, CHSY1 inhibition suppressed migration and cytokine production of macrophages, fibroblast-to-myofibroblast transition, and VSMC hyperproliferation. NOTCH3 signalling was found to be positively correlated with CHSY1 modulation. Conclusions We demonstrated that inhibiting CHSY1 is necessary and sufficient to block CS synthesis. Chsy1 KD by dsiRNA is an effective therapy to ameliorate hyperplastic arterial remodelling.

Stress memory of heart failure in hematopoietic niche promotes recurrence via adipocytic skewing of mesenchymal stromal cells

Abstract Background Heart failure (HF) is marked by recurrent acute decompensations, which poses significant treatment challenges in advanced stages. Our preceding work demonstrated that hematopoietic stem cells (HSCs) from HF-experienced mice induce cardiac fibrosis and dysfunction when transplanted, as a result of epigenetic alterations favoring myeloid hematopoiesis and impeding the differentiation of monocytes into cardiac mature macrophages. These findings hint at epigenetic modifications in HSCs as potential drivers of HF recurrence, suggesting their manipulation as a novel therapeutic strategy. However, the exact mechanisms by which HF-associated stress leads to these epigenetic changes remain unclear. Given the crucial role of bone marrow mesenchymal stromal cells (MSCs) in maintaining HSC stemness, this study explores the impact of cardiac stress on MSC function and its subsequent effect on HSCs. Purpose This study aims to elucidate the mechanisms behind the phenotypic changes in HSCs and to identify novel therapeutic targets to mitigate HF recurrence by investigating the role of MSCs in the hematopoietic niche under cardiac stress. Methods & Results Initially, we examined MSC phenotypic changes during HF using bulk and single-cell RNA sequencing. Results from transverse aortic constriction (TAC) model mice revealed a shift towards adipocyte differentiation under cardiac stress. Histological analyses confirmed an increase in adipocytes in TAC mice compared to controls, suggesting a stress-induced predisposition of MSCs towards adipocytic lineage commitment. This trend was further supported by ex vivo models using MSCs isolated from TAC mice. Notably, the proportion of adipocyte lineage-specific MSCs correlated with cardiac dysfunction severity. Subsequently, we assessed the impact of HF-conditioned MSCs on HF development by transplanting healthy HSCs with MSCs from control or TAC mice. Mice receiving HF-conditioned MSCs developed HF, evidenced by reduced ejection fraction and cardiac fibrosis. In these mice, a notable increase in HSC proliferation and a relative increase of myeloid cells within the peripheral blood were observed, along with an increase in proinflammatory cardiac macrophages. These findings suggest HF induces a "stress memory" in bone marrow MSCs. To test the potential of inhibiting adipocyte differentiation of MSCs in erasing this stress memory, we administered MSC phenotype-modulating agents to TAC mice, resulting in improved cardiac function and the disappearance of adipocytes from the bone marrow. Conclusions This study sheds light on how cardiac stress affects the bone marrow niche, leading to adipocytic skewing of MSCs and subsequent alterations in HSCs, thereby exacerbating cardiac dysfunction. The potential of targeting bone marrow niche components in HF treatment is highlighted.