Prenatal Diagnosis and Postnatal Outcome of Eight Cases with Criss-Cross Heart - A Multicenter Case Series.

OBJECTIVE: Criss-cross heart (CCH) is a rare congenital cardiac defect defined by crossing of ventricular inflow streams contributing to less than 0.1 % of all congenital heart anomalies. Due to its rarity and complexity, prenatal diagnosis in these patients remains challenging. We sought to describe prenatal findings and postnatal course in eight cases of prenatally diagnosed CCH. METHODS: This is a retrospective case series of prenatally diagnosed CCH in three centers between 2010-2017. We reviewed fetal echocardiograms as well as postnatal clinical charts and surgical reports. RESULTS: 8 cases of CCH were included. The median gestational age at diagnosis was 27 weeks. 7 patients were found with situs solitus, one fetus with situs ambiguous. In all patients, the four-chamber view was abnormal. There was atrioventricular discordance in half of the patients, while all patients showed ventriculoarterial discordance. All patients were found with additional cardiac anomalies, including ventricular septal defect, double outlet right ventricle, right aortic arch, atrial septal defect and pulmonary stenosis. Three patients underwent amniocentesis without pathological findings. All patients were born alive at a median gestational age of 38 + 2 weeks and survived our median follow-up of 181 days. CONCLUSION: CCH can be diagnosed prenatally by detailed fetal echocardiography when observing an abnormal four-chamber view with crossing of inflow streams into both ventricles and a lack of parallel orientation of the atrioventricular valve axis due to a clockwise or counterclockwise rotation of the ventricular mass along its axis. With the help of prenatal ultrasound, parental guidance and counselling as well as postnatal pediatric cardiac management can be warranted.

Natural history of pulmonary atresia with intact ventricular septum (PAIVS) and critical pulmonary stenosis (CPS) and prediction of outcome.

OBJECTIVES: To analyse prenatal parameters predicting biventricular (BV) outcome in pulmonary atresia with intact ventricular septum/critical pulmonary stenosis (PAIVS/CPS). METHODS: We evaluated 82 foetuses from 01/08 to 10/18 in 3 centres in intervals 1 (< 24 weeks), 2 (24-30 weeks) and 3 (> 30 weeks). RESULTS: 61/82 (74.4%) were livebirths, 5 (8.2%) lost for follow-up, 3 (4.9%) had compassionate care leaving 53 (64.6% of the whole cohort and 86.9% of livebirths) with intention to treat. 9 died, 44/53 (83.0%) survived. 24/38 (63.2%) with information on postnatal outcome had BV outcome, 14 (36.8%) non-BV outcome (2 × 1.5 circulation). One with BV outcome had prenatal valvuloplasty. Best single parameter for BV outcome was tricuspid/mitral valve (TV/MV) ratio (AUC 0.93) in intervals 2 and 3 (AUC 0.92). Ventriculo-coronary-arterial communications (VCAC) were present in 11 (78.6%) in non-BV outcome group vs. 2 (8.3%) in BV outcome group (p < 0.001). Tricuspid insufficiency (TI)-Vmax > 2.5 m/s was present in BV outcome group in75.0% (18/24) vs. 14.3% (2/14) in non-BV outcome group. Including the most predictive markers (VCAC presence, TI- Vmax < 2.5 m/s, TV/MV ratio < cutoff) to a score, non-BV outcome was correctly predicted when > 1 criterion was fulfilled in all cases. After recently published criteria for foetal intervention, only 4/9 (44.4%) and 5/14 (35.7%) in our interval 2 + 3 with predicted non-BV outcome would have been candidates for intervention. Two (1 × intrauterine intervention) in interval 2, two in interval 3 reached BV outcome and one 1.5 circulation without intervention. CONCLUSION: TV/MV ratio as simple parameter has high predictive value. After our score, non-BV outcome was correctly predicted in all cases. Criteria for foetal intervention must further be evaluated.

Outcome and Associated Findings in Individuals with Pre- and Postnatal Diagnosis of Tetralogy of Fallot (TOF) and Prediction of Early Postnatal Intervention.

PURPOSE: The aim of our retrospective evaluation was to compare the outcome of patients with prenatal and postnatal diagnosis of Tetralogy of Fallot (TOF) and to analyze prenatal echocardiographic parameters predicting intervention within 30 days postnatal. MATERIALS AND METHODS: We evaluated 142 patients in our pediatric heart center and prenatal diagnosis center and prenatal practice Praenatal plus in Cologne between 01/08-06/16. RESULTS: Within the prenatal diagnosis group, 6/74 fetuses (8.1 %) had TOF with pulmonary atresia (TOF-PA), and 6 (8.1 %) had absent pulmonary valve syndrome (TOF-APVS). 14 (18.9 %) had an abnormal karyotype including 9/14 (64.3 %) with microdeletion 22q11.2. 25 (33.8 %) had extracardiac malformation. 4 (5.4 %) had agenesis of ductus arteriosus (DA), 22 (29.7 %) had right aortic arch (RAA) and 9 (12.2 %) had major aortopulmonary collateral arteries (MAPCAs). Within the postnatal diagnosis group, no patient had TOF-PA, 4/68 (5.9 %) had TOF-APVS. 12 (17.6 %) had extracardiac malformations, 9 (13.2 %) had an abnormal karyotype including 2/9 with microdeletion 22q11.2. 10 (14.7 %) had RAA, 9 (13.2 %) had MAPCAs. There were no cases with agenesis of DA. Increasing z-score values of the left/right pulmonary artery (LPA/RPA) prenatally were associated with a lower probability for early postnatal intervention (RPA: p = 0.017; LPA: p = 0.013). Within the prenatal diagnosis group, 12 of 41 (29.3 %) live-born patients with follow-up and intention to treat needed early intervention versus 7 (10.3 %) in the postnatal diagnosis group (p = 0.02). Within the postnatal diagnosis group, there were no deaths, while 2 (4.9 %) post-intervention deaths occurred in the prenatal diagnosis group. CONCLUSION: There are no significant differences concerning post-intervention survival in the prenatal diagnosis group versus the postnatal diagnosis group. Complex cases may be underrepresented in the postnatal diagnosis group. Smaller RPA/LPA values prenatally seem to be associated with early postnatal intervention.

In Vitro Grown Micro-Tissues for Cardiac Cell Replacement Therapy in Vivo.

BACKGROUND/AIMS: Different approaches have been considered to improve heart reconstructive medicine and direct delivery of pluripotent stem cell-derived cardiomyocytes (PSC-CMs) appears to be highly promising in this context. However, low cell persistence post-transplantation remains a bottleneck hindering the approach. Here, we present a novel strategy to overcome the low engraftment of PSC-CMs during the early post-transplantation phase into the myocardium of both healthy and cryoinjured syngeneic mice. METHODS: Adult murine bone marrow mesenchymal stem cells (MSCs) and PSC-CMs were co-cultured on thermo-responsive polymers and later detached through temperature reduction, resulting in the protease-free generation of cell clusters (micro-tissues) composed of both cells types. Micro-tissues were transplanted into healthy and cryo-injured murine hearts. Short term cell retention was quantified by real-time-PCR. Longitudinal cell tracking was performed by bioluminescence imaging for four weeks. Transplanted cells were further detected by immunofluorescence staining of tissue sections. RESULTS: We demonstrated that in vitro grown micro-tissues consisting of PSC-CMs and MSCs can increase cardiomyocyte retention by >10fold one day post-transplantation, but could not fully rescue a further cell loss between day 1 and day 2. Neutrophil infiltration into the transplanted area was detected in healthy hearts and could be attributed to the cellular implantation rather than tissue damage exerted by the transplantation cannula. Injected PSC-CMs were tracked and successfully detected for up to four weeks by bioluminescence imaging. CONCLUSION: This approach demonstrated that in vitro grown micro-tissues might contribute to the development of cardiac cell replacement therapies.

Severe heart failure and the need for mechanical circulatory support and heart transplantation in pediatric patients with myocarditis: Results from the prospective multicenter registry "MYKKE".

Myocarditis represents an important cause for acute heart failure. MYKKE, a prospective multicenter registry of pediatric patients with myocarditis, aims to gain knowledge on courses, diagnostics, and therapy of pediatric myocarditis. The role of mechanical circulatory support (MCS) in children with severe heart failure and myocarditis is unclear. The aim of this study was to determine characteristics and outcome of patients with severe heart failure requiring MCS and/or heart transplantation. The MYKKE cohort between September 2013 and 2016 was analyzed. A total of 195 patients were prospectively enrolled by 17 German hospitals. Twenty-eight patients (14%) received MCS (median 1.5 years), more frequently in the youngest age group (0-2 years) than in the older groups (P < 0.001; 2-12 and 13-18 years). In the MCS group, 50% received a VAD, 36% ECMO, and 14% both, with a survival rate of 79%. The weaning rate was 43% (12/28). Nine (32%) patients were transplanted, one had ongoing support, and six (21%) died. Histology was positive for myocarditis in 63% of the MCS group. Patients within the whole cohort with age <2 years and/or ejection fraction <30% had a significantly worse survival with high risk for MCS, transplantation, and death (P < 0.001). Myocarditis represents a life-threatening disease with an overall mortality of 4.6% in this cohort. The fulminant form more often affected the youngest, leading to significantly higher rate of MCS, transplantation, and mortality. MCS represents an important and life-saving therapeutic option in children with myocarditis with a weaning rate of 43%.

Transcatheter left atrial decompression in patients with dilated cardiomyopathy: bridging to cardiac transplantation or recovery.

BACKGROUND: Left atrial congestion results from backward failure in dilated cardiomyopathy. We aimed to evaluate feasibility and efficacy of percutaneous atrioseptostomy to create a restrictive atrial septum defect in management of dilated cardiomyopathy.Methods and resultsFrom June 2009 to December 2016, 27 interventions comprised left atria decompressions in 22 dilated cardiomyopathy patients; 9 females; age: 24 days to 36.9 years; weight: 3-50 kg; NYHA-/Ross class IV (n=16). Mean left ventricular ejection fraction was 21.5±9.7% and brain natriuretic peptide was 2291±1992 pg/ml. Dilated cardiomyopathy was classified as chronic (n=9); acute (n=1) myocarditis; idiopathic (n=5); left ventricular non-compaction (n=4); mitochondriopathy, pacemaker induced, and arrhythmogenic (n=3). Atrioseptostomy was concomitantly performed with myocardial biopsies 6.5 days (±11.7) after admission (n=11). Trans-septal puncture was used in 18 patients; foramen ovale dilatation was done in four patients. Mean balloon size was 11 mm (range 7-14 mm); total procedure time was 133±38 minutes. No procedural complications were observed. Mean left atrial pressure decreased from 15.8±6.8 to 12.2±4.8 mmHg (p=0.005), left/right atrial pressure gradient from 9.6±5.6 to 5±3.5 mmHg; brain natriuretic peptide (n=18) decreased from 1968±1606 to 830±1083 pg/ml (p=0.01). One patient unsuitable for heart transplantation died at home despite additionally performed pulmonary artery banding and three further left atrial decompressions; five patients were bridged to transplantation, two died afterwards. Functional recovery occurred in the remaining 14 patients and in six after additional pulmonary artery banding. No patient required assist device. CONCLUSIONS: Percutaneous left atrial decompression is an age-independent, effective palliation treating patients with dilated cardiomyopathy.

A word of caution: diabolic behaviour of AndraStents®: inflation of supporting balloon leads to "diabolo"-misconfiguration of the stent.

AIMS: Transcatheter implantation of pulmonary balloon-expandable stent-valves requires pre-stenting of the right ventricular outflow tract with large calibre stents. To increase awareness of the associated risks of this part of transcatheter pulmonary valve replacement therapy, we report potential fatal complications during the implantation of AndraStents® in the right ventricular outflow tract in six cases from five different European institutions and their management. METHOD AND RESULT: We present a retrospective case series analysis looking at the time period from 2013 to 2018. Of 127 AndraStents® implanted in the right ventricular outflow tract, in six patients, age from 13 to 71 years, a misconfiguration of the AndraStent® occurred forming a "diabolo"-configuration. During inflation of the balloon, the stent showed extreme "dog-boning", an expansion of the stent at both ends with the middle part remaining unexpanded. This led to rupture of the balloon and loss of manoeuvrability in four patients. Out of the total six cases, in four patients the stent was eventually expanded with high-pressure balloons, and in one case the stent was surgically retrieved. In one patient, in whom a percutaneous retrieval of the embolised stent was attempted, a fatal bleeding occurred. CONCLUSIONS: Pre-stenting of the right ventricular outflow tract by AndraStents® can lead to misconfiguration of the stent with potentially fatal complications. Rescue strategies of misconfigured stents include stent inflation and placement with high pressure non-compliant balloons or surgical backup. Interventional retrieval measures of AndraStents® cannot be advised.

Percutaneous pulmonary valve implantation for reconstruction of a patch-repaired right ventricular outflow tract.

Percutaneous pulmonary valve implantation (PPVI) is nowadays an accepted treatment option to repair post-surgical conduit dysfunction of the right ventricular outflow tract (RVOT). In addition, many patients need a pulmonary valve to reconstruct a hemodynamically incompetent native or conduit free outflow tract. Based on our experience with percutaneous stent-valve placement in a cohort of 125 patients, we report here transvenous reconstruction of a conduit-free, patch repaired outflow tract by utilizing balloon-expandable stent-valves in 23 patients with a median age of 22 years (5-60 years). In 20 patients, the step-by-step procedure was performed uneventful with the aimed success. Severe RVOT dysfunction in term of a clinical relevant regurgitation could be changed to mild, as it was confirmed by follow-up color Doppler echocardiography. In a 5-year-old girl a Melody® valve was placed as a surgical-interventional hybrid approach. In one patient, the procedure was complicated by stent embolization during preparation of the RVOT for stent-valve implantation. Reposition of the embolized stent was nevertheless successful for finishing percutaneous valve-implantation. In one patient, surgical approach became necessary because of the inability to advance the balloon-mounted stent-valve through a pre-stented RVOT. Considering the current available balloon-expandable stent-valves, transvenous pulmonary valve implantation is feasible to treat even an incompetent conduit-free RVOT. However, preparation of the RVOT by pre-stenting, in most patients with more than two stents in telescope technique remains challenging. Reconstruction of RVOT by the current available valves is promising only for a carefully selected group of patients.

Endocardial Fibroelastosis of the Left Ventricle Affects Right Ventricular Performance in Fetuses with Hypoplastic Left Heart Syndrome: A Prospective Study Using M-Mode, PW- and Tissue Doppler Techniques.

PURPOSE: Myocardial function (MF) of the systemic right ventricle (RV) influences the postnatal course of neonates with hypoplastic left heart syndrome (HLHS). Our study examines whether the presence of endocardial fibroelastosis of the left ventricle (LV EFE) influences MF of the RV in HLHS fetuses. MATERIALS AND METHODS: A prospective study was conducted including 10 controls (group 1), 10 HLHS fetuses with (group 2) and 10 without LV EFE (group 3) - all matched for gestational age. M-mode was used to assess tricuspid plane systolic excursion (TAPSE) and the shortening fraction (SF). PW-Doppler-derived and PW-TDI-derived velocities were assessed. E/A, E/e', e'/a' ratios and the myocardial performance index (mpi') were calculated. RESULTS: The examination of MF revealed significantly lower s' velocities (p < 0.05) and higher values for SF in group 2 compared to group 3. e'/a' ratio, et' (ejection time), E wave velocity, E/e' and SF showed significantly higher values in group 2 compared to group 1. In group 2 a' velocity increased significantly over gestational age. In group 3 but not in group 2, TAPSE increased during gestation. CONCLUSION: These significant differences in MF between the groups might lend support to the notion of negative ventricular-ventricular interaction in the case of HLHS with LV EFE possibly influencing surgical outcomes.

Toward evidence-based diagnosis of myocarditis in children and adolescents: Rationale, design, and first baseline data of MYKKE, a multicenter registry and study platform.

The aim of this registry is to provide data on age-related clinical features of suspected myocarditis and to create a study platform allowing for deriving diagnostic criteria and, at a later stage, testing therapeutic interventions in patients with myocarditis. STUDY DESIGN AND RESULTS: After an initial 6-month pilot phase, MYKKE was opened in June 2014 as a prospective multicenter registry for patients from pediatric heart centers, university hospitals, and community hospitals with pediatric cardiology wards in Germany. Inclusion criteria consisted of age<18 years and hospitalization for suspected myocarditis as leading diagnosis at the discretion of the treating physician. By December 31, 2015, fifteen centers across Germany were actively participating and had enrolled 149 patients. Baseline data reveal 2 age peaks (<2 years, >12 years), show higher proportions of males, and document a high prevalence of severe disease courses in pediatric patients with suspected myocarditis. Severe clinical courses and early adverse events were more prevalent in younger patients and were related to severely impaired leftventricular ejection fraction at initial presentation. SUMMARY: MYKKE represents a multicenter registry and research platform for children and adolescents with suspected myocarditis that achieve steady recruitment and generate a wide range of real-world data on clinical course, diagnostic workup, and treatment of this group of patients. The baseline data reveal the presence of 2 age peaks and provide important insights into the severity of disease in children with suspected myocarditis. In the future, MYKKE might facilitate interventional substudies by providing an established collaborating network using common diagnostic approaches.

Prenatal diagnosis of functionally univentricular heart, associations and perinatal outcomes.

OBJECTIVE: Functionally univentricular hearts (UVHs) represent cardiac anomalies in which either the pulmonary or systemic circulation cannot be supported independently. The purpose of our study was to determine perinatal outcomes after prenatal diagnosis of functionally UVH. METHODS: We retrospectively evaluated patients who presented between 2008 and June 2015 in our centre and in prenatal practice praenatal.de in Cologne. We included double inlet left ventricle (DILV), tricuspid valve atresia (TA), pulmonary valve atresia and intact ventricular septum (PA:IVS), unbalanced atrioventricular septal defect (AVSD), heterotaxy, hypoplastic left heart syndrome (HLHS) and hypoplastic left heart complex (HLHC). RESULTS: Of initially 155 patients, 128 were liveborn (82.6%). Ten neonates (7.8%) were lost to follow-up, in three (2.5%) neonates, parents decided for compassionate care. Overall survival after prenatal diagnosis of functionally UVH was 67.1%, and 90.4% on an intention-to-treat basis. Survival after surgery reached 93.7%. The majority of deaths occurred within the group of dominant RV (10/74, 13.5%). High risk HLHS with restrictive foramen ovale was associated with the lowest survival rate (13/17, 76.5%) with significant difference compared to survival rate in dominant LV (40/41, 97.6%, p < 0.05). CONCLUSION: These results should be explained to parents to ensure informed decisions and counselling. © 2016 John Wiley & Sons, Ltd.

Low serum 25-hydroxyvitamin D levels and secondary hyperparathyroidism in Fontan patients.

BACKGROUND: Limited data exist on the vitamin D status in Fontan patients. We determined the prevalence and potential risk factors of vitamin D deficiency in this patient subset. Methods and results Data were collected from 27 Fontan patients (55.6% male, mean age 8.1±5.3 years). Protein-losing enteropathy was diagnosed in six patients (22.2%). Vitamin D deficiency was defined as a serum 25-hydroxyvitamin D level of <20 ng/ml. The neutrophil-to-lymphocyte ratio, a marker of systemic inflammation, was calculated. Associations between laboratory measurements and patient characteristics were explored. Mean serum 25-hydroxyvitamin D level was 14.1±10.4 ng/ml. Vitamin D deficiency was found in 19/27 patients (70.3%). Only skin type was associated with vitamin D deficiency (p=0.04). Hyperparathyroidism was present in 5/21 (23.8%) patients, and was more prevalent in patients with protein-losing enteropathy (p<0.001). Parathyroid hormone levels correlated with parameters of systemic inflammation (neutrophil-to-lymphocyte ratio: r=0.484, p=0.026; relative lymphocyte count: r=-0.635, p=0.002). Vitamin D supplementation significantly increased serum 25-hydroxyvitamin D levels (p<0.0001), and was accompanied by a reduction in parathyroid hormone concentrations (p=0.032). CONCLUSIONS: A high prevalence of vitamin D deficiency was found among Fontan patients, independent of age, time after Fontan procedure, ventricular morphology, and presence of protein-losing enteropathy. A potentially important link between parathyroid hormone levels and systemic inflammation is suggested.

Electrophysiological characteristics of embryonic stem cell-derived cardiomyocytes are cell line-dependent.

BACKGROUND: Modelling of cardiac development, physiology and pharmacology by differentiation of embryonic stem cells (ESCs) requires comparability of cardiac differentiation between different ESC lines. To investigate whether the outcome of cardiac differentiation is consistent between different ESC lines, we compared electrophysiological properties of ESC-derived cardiomyocytes (ESC-CMs) of different murine ESC lines. METHODS: Two wild-type (D3 and R1) and two transgenic ESC lines (D3/aPIG44 and CGR8/AMPIGX-7) were differentiated under identical culture conditions. The transgenic cell lines expressed enhanced green fluorescent protein (eGFP) and puromycin-N-acetyltransferase under control of the cardiac specific α-myosin heavy chain (αMHC) promoter. Action potentials (APs) were recorded using sharp electrodes and multielectrode arrays in beating clusters of ESC-CMs. RESULTS: Spontaneous AP frequency and AP duration (APD) as well as maximal upstroke velocity differed markedly between unpurified CMs of the four ESC lines. APD heterogeneity was negligible in D3/aPIG44, moderate in D3 and R1 and extensive in CGR8/AMPIGX-7. Interspike intervals calculated from long-term recordings showed a high degree of variability within and between recordings in CGR8/AMPIGX-7, but not in D3/aPIG44. Purification of the αMHC+ population by puromycin treatment posed only minor changes to APD in D3/aPIG44, but significantly shortened APD in CGR8/AMPIGX-7. CONCLUSION: Electrophysiological properties of ESC-CMs are strongly cell line-dependent and can be influenced by purification of cardiomyocytes by antibiotic selection. Thus, conclusions on cardiac development, physiology and pharmacology derived from single stem cell lines have to be interpreted carefully.

Focal myocardial fibrosis assessed by late gadolinium enhancement cardiovascular magnetic resonance in children and adolescents with dilated cardiomyopathy.

BACKGROUND: Different patterns of late gadolinium enhancement (LGE) including mid-wall fibrosis using cardiovascular magnetic resonance (CMR) have been reported in adult patients presenting with non-ischemic dilated cardiomyopathy (DCM). In these studies, LGE was associated with pronounced LV remodelling and predicted adverse cardiac outcomes. Accordingly, the purpose of our study was to determine the presence and patterns of LGE in children and adolescents with DCM. METHODS: Patients <18 years of age presenting with severe congestive heart failure who were admitted for evaluation of heart transplantation at our centre underwent CMR examination which consisted of ventricular functional analysis and assessment of LGE for detection of myocardial fibrosis. Ischemic DCM was excluded by coronary angiography, and right ventricular endomyocardial biopsies ruled out acute myocarditis. RESULTS: Thirty-one patients (mean age 2.1 ± 4.2 years) with severe LV dilatation (mean indexed LVEDV 136 ± 48 ml/m(2)) and LV dysfunction (mean LV-EF 23 ± 8%) were examined. LGE was detected in 5 of the 31 patients (16%) appearing in various patterns characterized as mid-wall (n = 1), focal patchy (n = 1), RV insertion site (n = 1) and transmural (n = 2). Based on histopathological analysis, 4 of the 5 LGE positive patients had lymphocytic myocarditis, whereas one patient was diagnosed with idiopathic DCM. CONCLUSIONS: In children and adolescents with DCM, focal histologically proven myocardial fibrosis is rarely detected by LGE CMR despite marked LV dilatation and severely depressed LV function. LGE occurred in various patterns and mostly in patients with inflammatory cardiomyopathy. It remains unclear whether myocardial fibrosis in childhood DCM reflects different endogenous repair mechanisms that enable favourable reverse remodelling. Larger trials are needed to assess the prognostic implications of LGE in childhood DCM.

Baicalin maintains late-stage functional cardiomyocytes in embryoid bodies derived from murine embryonic stem cells.

BACKGROUND/AIMS: Low efficiency of cardiomyocyte (CM) differentiation from embryonic stem (ES) cells limits their therapeutic use. The objective of this study was to investigate the effect of baicalin, a natural flavonoid compound, on the in vitro cardiac differentiation of murine ES cells. METHODS: The induction of ES cells into cardiac-like cells was performed by embryoid body (EB)-based differentiation method. The electrophysiological properties of the ES cell-derived CMs (ES-CMs) were measured by patch-clamp. The biomarkers of ES-CMs were determined by quantitative RT-PCR and immunofluorescence. RESULTS: Continuous baicalin treatment decreased the size of EBs, and increased the proportion of α-actinin-positive CMs and transcript level of cardiac specific markers in beating EBs by inducing cell death of non-CMs. Baicalin increased the percentage of working ES-CMs which had typical responses to ß-adrenergic and muscarinic stimulations. CONCLUSION: Baicalin maintains the late-stage functional CMs in EBs derived from murine ES cells. This study describes a new insight into the various biological effects of baicalin on cardiac differentiation of pluripotent stem cells.

Left Ventricular Physiology and Ventricular-Vascular Interactions in Young Patients After Heart Transplantation.

Background In patients after heart transplantation, systemic arterial hypertension and enhanced central aortic stiffness contribute to increased ventricular afterload, which might lead to graft dysfunction. The aim of our study was to characterize systemic arterial elastance and its impact on left ventricular function and ventriculo-arterial coupling in a cohort of children, adolescents, and young adults after heart transplantation using invasive conductance catheter technique. Methods and Results Thirty patients who had heart transplants (age, 20.0±6.5 years, 7 female) underwent invasive cardiac catheterization including pressure-volume loop analysis. Load-independent parameters of systolic (ventricular elastance [Ees]) and diastolic (ventricular compliance) function as well as systemic arterial elastance (Ea, end-systolic pressure/stroke volume) and ventriculo-arterial coupling (Ea/Ees) were assessed at baseline level and during dobutamine infusion (10 µg/kg/min). Ees showed an appropriate increase under inotropic stimulation from 0.43 (0.11-2.52) to 1.00 (0.20-5.10) mm Hg/mL/m2 (P<0.0001), whereas ventricular compliance remained rather unchanged (0.16±0.10 mm Hg/mL/m2 to 0.12±0.07 mm Hg/mL/m2; P=0.10). Ventriculo-arterial coupling Ea/Ees was abnormal at rest and did not improve significantly under dobutamine (1.7 [0.6-6.7] to 1.3 [0.5-4.9], P=0.70) due to a simultaneous rise in Ea from 0.71 (0.37-2.82) to 1.10 (0.52-4.03) mm Hg/mL/m2 (P<0.0001). Both Ees and ventricular compliance were significantly associated with Ea at baseline and under dobutamine infusion. Conclusions Patients who underwent heart transplantation show impaired ventriculo-arterial coupling at rest and under inotropic stimulation despite preserved left ventricular contractile reserve. An abnormal response in vascular function resulting in increased afterload seems to represent an important factor that may play a role for the development of late graft failure.

Exercise-dependent changes in ventricular-arterial coupling and aortopulmonary collateral flow in Fontan patients: a real-time CMR study.

AIMS: Inefficient ventricular-arterial (V-A) coupling has been described in Fontan patients and may result in adverse haemodynamics. A varying amount of aortopulmonary collateral (APC) flow is also frequently present that increases volume load of the single ventricle. The aim of the study was to assess changes in V-A coupling and APC flow during exercise CMR. METHODS AND RESULTS: Eighteen Fontan patients (age 24 ± 3 years) and 14 controls (age 23 ± 4 years) underwent exercise CMR using a cycle ergometer. Ventricular volumetry and flow measurements in the ascending aorta (AAO), inferior (IVC), and superior (SVC) vena cava were assessed using real-time sequences during stepwise increases in work load. Measures of systemic arterial elastance Ea, ventricular elastance Ees, and V-A coupling (Ea/Ees) were assessed. APC flow was quantified as AAO - (SVC + IVC). Ea remained unchanged during all levels of exercise in both groups (P = 0.39 and P = 0.11). Ees increased in both groups (P = 0.001 and P < 0.001) with exercise but was lower in the Fontan group (P = 0.04). V-A coupling was impaired in Fontan patients at baseline (P = 0.04). Despite improvement during exercise (P = 0.002) V-A coupling remained impaired compared with controls (P = 0.001). Absolute APC flow in Fontan patients did not change during exercise even at maximum work load (P = 0.98). CONCLUSIONS: Inefficient V-A coupling was already present at rest in Fontan patients and aggravated during exercise due to a limited increase in ventricular contractility which demonstrates the importance of a limited functional reserve of the single ventricle. APC flow remained unchanged suggesting no further increase in volume load during exercise.

Direct contact of umbilical cord blood endothelial progenitors with living cardiac tissue is a requirement for vascular tube-like structures formation.

The umbilical cord blood derived endothelial progenitor cells (EPCs) contribute to vascular regeneration in experimental models of ischaemia. However, their ability to participate in cardiovascular tissue restoration has not been elucidated yet. We employed a novel coculture system to investigate whether human EPCs have the capacity to integrate into living and ischaemic cardiac tissue, and participate to neovascularization. EPCs were cocultured with either living or ischaemic murine embryonic ventricular slices, in the presence or absence of a pro-angiogenic growth factor cocktail consisting of VEGF, IGF-1, EGF and bFGF. Tracking of EPCs within the cocultures was performed by cell transfection with green fluorescent protein or by immunostaining performed with anti-human vWF, CD31, nuclei and mitochondria antibodies. EPCs generated vascular tube-like structures in direct contact with the living ventricular slices. Furthermore, the pro-angiogenic growth factor cocktail reduced significantly tubes formation. Coculture of EPCs with the living ventricular slices in a transwell system did not lead to vascular tube-like structures formation, demonstrating that the direct contact is necessary and that the soluble factors secreted by the living slices were not sufficient for their induction. No vascular tubes were formed when EPCs were cocultured with ischaemic ventricular slices, even in the presence of the pro-angiogenic cocktail. In conclusion, EPCs form vascular tube-like structures in contact with living cardiac tissue and the direct cell-to-cell interaction is a prerequisite for their induction. Understanding the cardiac niche and micro-environmental interactions that regulate EPCs integration and neovascularization are essential for applying these cells to cardiovascular regeneration.

Integration properties of Wharton's jelly-derived novel mesenchymal stem cells into ventricular slices of murine hearts.

Wharton's jelly (WJ) is a rich source of multiple-lineage differentiating cells, recently proposed for cell replacement therapy. However, their ability to integrate into the cardiac tissue has not been elucidated, yet. We employed in vitro cardiac transplantation models to investigate the capacity of a novel population of human WJ-derived mesenchymal stem cells (nMSCs) to integrate into both living and ischemic cardiac tissue. NMSCs were characterized for the expression of stem/progenitor cell genes and proteins, as well as for multi-lineage differentiation potential. To assess their integration properties, nMSCs were cocultured with either living or ischemic embryonic murine ventricular slices. Immunohistochemical analyses were performed on cryosections of cocultured preparations to allow human cells tracking within the cocultures. Results showed that nMSCs shared MSC and endothelial colony-forming cell characteristics at gene, protein, and functional levels. NMSCs were markedly chemoattracted towards the ventricular slices, integrating robustly into the depth of both living and ischemic cardiac tissue. In conclusion, the functional ability of WJ-derived cells to populate the cardiac tissue could be validated in vitro. The transplantation models described could be further used to depict the mechanisms of WJ-derived cells integration into the cardiac tissue, contributing to optimization of reliable cell therapies for cardiac repair.

Comparison of contractile behavior of native murine ventricular tissue and cardiomyocytes derived from embryonic or induced pluripotent stem cells.

Cardiomyocytes generated from embryonic stem cells (ESCs) and induced pluripotent stem (iPS) cells are suggested for repopulation of destroyed myocardium. Because contractile properties are crucial for functional regeneration, we compared cardiomyocytes differentiated from ES cells (ESC-CMs) and iPS cells (iPS-CMs). Native myocardium served as control. Murine ESCs or iPS cells were differentiated 11 d in vitro and cocultured 5-7 d with irreversibly injured myocardial tissue slices. Vital embryonic ventricular tissue slices of similar age served for comparison. Force-frequency relationship (FFR), effects of Ca(2+), Ni(2+), nifedipine, ryanodine, beta-adrenergic, and muscarinic modulation were studied during loaded contractions. FFR was negative for ESC-CMs and iPS-CMs. FFR was positive for embryonic tissue and turned negative after treatment with ryanodine. In all groups, force of contraction and relaxation time increased with the concentration of Ca(2+) and decreased with nifedipine. Force was reduced by Ni(2+). Isoproterenol (1 microM) increased the force most pronounced in embryonic tissue (207+/-31%, n=7; ESC-CMs: 123+/-5%, n=4; iPS-CMs: 120+/-4%, n=8). EC(50) values were similar. Contractile properties of iPS-CMs and ESC-CMs were similar, but they were significantly different from ventricular tissue of comparable age. The results indicate immaturity of the sarcoplasmic reticulum and the beta-adrenergic response of iPS-CMs and ESC-CMs.