Fetal Valve Research Articles

APOE-NOTCH axis governs elastogenesis during human cardiac valve remodeling.

Valve remodeling is a process involving extracellular matrix organization and elongation of valve leaflets. Here, through single-cell RNA sequencing of human fetal valves, we identified an elastin-producing valve interstitial cell (VIC) subtype (apolipoprotein E (APOE)+, elastin-VICs) spatially located underneath valve endothelial cells (VECs) sensing unidirectional flow. APOE knockdown in fetal VICs resulted in profound elastogenesis defects. In valves with pulmonary stenosis (PS), we observed elastin fragmentation and decreased expression of APOE along with other genes regulating elastogenesis. Cell-cell interaction analysis revealed that jagged 1 (JAG1) from unidirectional VECs activates elastogenesis in elastin-VICs through NOTCH2. Similar observations were made in VICs cocultured with VECs under unidirectional flow. Notably, a drastic reduction of JAG1-NOTCH2 was also observed in PS valves. Lastly, we found that APOE controls JAG1-induced NOTCH activation and elastogenesis in VICs through the extracellular signal-regulated kinase pathway. Our study suggests important roles of both APOE and NOTCH in regulating elastogenesis during human valve remodeling.

Abstract P1178: APOE-NOTCH Axis Governs Elastogenesis During Human Cardiac Valve Remodeling

Background: Valve remodeling is a complex process involving extracellular matrix organization, development of trilaminar structures, and physical elongation of valve leaflets. However, the cellular and molecular mechanisms regulating valve remodeling and their roles in congenital valve disorders remain poorly understood. Methods: Semilunar valves and atrioventricular valves from healthy and age-matched human fetal hearts with pulmonary stenosis (PS) were collected. Single-Cell RNA-sequencing (scRNA-seq) was performed to determine the transcriptomic landscape of multiple valvular cell subtypes in valve remodeling and disease. Results: scRNA-seq analysis of healthy human fetal valves identified a novel APOE+ elastin-producing valve interstitial cell (Elastin-VIC) subtype spatially located underneath VECs in the direction of unidirectional flow. Knockdown of APOE in fetal VICs resulted in significant elastogenesis defects. In pulmonary valve with PS, we observed decreased expression of APOE and other genes regulating elastogenesis such as EMILIN1 and LOXL1 , as well as elastin fragmentation. Cell-cell interaction analysis revealed that JAG1 from unidirectional VECs activates NOTCH signaling in Elastin-VICs through NOTCH3. In vitro Jag1 treatment in VICs increased the expression of elastogenesis-related genes and enhanced contractile functions with related gene expression. This was accompanied by activation of NOTCH signaling and elastogenesis observed in VICs co-cultured with VECs in the presence of unidirectional flow. Notably, we found that the JAG1-NOTCH3 signaling pair was drastically reduced in the PS valves. Lastly, we demonstrated that APOE is indispensable for JAG1-induced NOTCH activation in VICs, reinforcing the presence of a synergistic intrinsic and external regulatory network involving APOE and NOTCH signaling that is responsible for regulating elastogenesis during human valve remodeling. Conclusion: scRNA-seq analysis of human fetal valves identified a novel Elastin-VIC subpopulation, and revealed mechanism of APOE and NOTCH signaling mediated elastogenesis during valve remodeling, which provided opportunity to understand pathogenesis of elastic malformation within congenital valve disease.

Abstract 9555: Human Valve Atlas in Health and Disease

Background: Semilunar and atrioventricular valves have distinct structures and are often affected differently in congenital valve diseases (CVD). Here we aim to define and compare the cellular composition and transcriptomic signatures of four different human fetal valves, which provide a reference map to engineer valves in vitro , and to study valve-specific impairment in CVD. Methods: Aortic, pulmonary, mitral, and tricuspid valves were barcoded respectively from a healthy human fetal heart at gestational day 105. Single-cell (sc)RNA-seq was performed. Spatial localization of new subpopulations was determined by immunostaining and in situ hybridization. Cell-cell interaction was revealed by cell-chat. Results: scRNA-seq analysis revealed major cell types including endothelial (VECs), interstitial (VICs), and immune cells. In addition to reported collagen & glycosaminoglycan (GAG) VIC in mice, VIC sub-clustering identified two human-specific APOE+ and CLDN11+ subpopulations. APOE+ VICs specifically located underneath VECs facing unidirectional flow, indicating cell-cell interaction of APOE+ VICs & VECs. VEC sub-clustering identified lymphatic VECs under turbulent flow, while CD55+ & PTGDS+ VECs under unidirectional flow. Cell-chat uncovered NOTCH3-JAG1 pairs in facilitating the co-development of spatially adjacent APOE+ VICs & PTGDS+ VECs. To further uncover valve-specific signatures, we compared gene expression profiles of four valves. In lymphatic VECs, genes regulating BMP pathway were enriched in semilunar valves. In GAG VICs, MAPK pathway was specifically enriched in pulmonary valve, indicating development of different valves may need activation of different pathways. Interestingly, when comparing valve with pulmonary atresia versus healthy pulmonary valve using scRNA-seq, both MAPK related genes and GAG VICs were significantly reduced, suggesting impaired MAPK may contribute to pulmonary-specific loss of GAG VICs leading to its abnormal development. Conclusion: Our high-resolution atlas of human fetal valves revealed subtypes of VIC & VEC with unique spatial locations. Comparison of four valves identified pulmonary valve-specific MAPK pathway that may explain loss of GAG VICs in patients with pulmonary atresia.

Local fluid shear stress operates a molecular switch to drive fetal semilunar valve extension.

While much is known about the genetic regulation of early valvular morphogenesis, mechanisms governing fetal valvular growth and remodeling remain unclear. Hemodynamic forces strongly influence morphogenesis, but it is unknown whether or how they interact with valvulogenic signaling programs. Side-specific activity of valvulogenic programs motivates the hypothesis that shear stress pattern-specific endocardial signaling controls the elongation of leaflets. We determined that extension of the semilunar valve occurs via fibrosa sided endocardial proliferation. Low OSS was necessary and sufficient to induce canonical Wnt/β-catenin activation in fetal valve endothelium, which in turn drives BMP receptor/ligand expression, and pSmad1/5 activity essential for endocardial proliferation. In contrast, ventricularis endocardial cells expressed active Notch1 but minimal pSmad1/5. Endocardial monolayers exposed to LSS attenuate Wnt signaling in a Notch1 dependent manner. Low OSS is transduced by endocardial cells into canonical Wnt signaling programs that regulate BMP signaling and endocardial proliferation. In contrast, high LSS induces Notch signaling in endocardial cells, inhibiting Wnt signaling and thereby restricting growth on the ventricular surface. Our results identify a novel mechanically regulated molecular switch, whereby fluid shear stress drives the growth of valve endothelium, orchestrating the extension of the valve in the direction of blood flow.

Prenatal evaluation of fetal atrioventricular valves by real-time 4D volume imaging with electronic matrix probe

BackgroundThe purpose of this study is to evaluate the feasibility using real-time four-dimensional (RT 4D) volume imaging with electronic matrix probe to observe the morphology of atrioventricular valves in normal and abnormal fetuses, measure the area and circumference of atrioventricular valves in normal fetuses and analyze the correlation with gestational age.MethodsRT 4D volume imaging with electronic matrix probe was used to collect cardiac volume data of 162 normal fetuses with the gestational age from 22 to 32 weeks and 19 fetuses with atrioventricular valves abnormalities were also enrolled. All the volume data were analyzed and processed in real-time. The morphology of mitral and tricuspid valves was observed in surface mode. The area and circumference of valves were measured in a 4D render view at the end of diastole and analyzed the correlation with gestational age.ResultsIn 148 of 162 fetuses (91%), the 4D rendered image could be successfully obtained, which clearly showed the morphology of the atrioventricular valves. The area and circumference of mitral and tricuspid valves were positively correlated with gestational age (P < 0.01). Furthermore, 4D rendered images were successfully obtained in 17 of 19 fetuses (89%) with atrioventricular valves abnormalities. ConclusionsThe reference range of the area and circumference of atrioventricular valves in normal fetuses at different gestational weeks could be determined by using the RT 4D volume imaging with electronic matrix probe, which can provide certain diagnostic information for the clinic. The RT 4D images could display the valves morphology vividly in both normal and abnormal fetuses, including some subtle lesions which are not identified by traditional two-dimensional (2D) echocardiography. It is feasible to use the RT 4D volume imaging with electronic matrix probe to perform the prenatal evaluation in the fetal atrioventricular valves.

Identification of a peripheral blood gene signature predicting aortic valve calcification.

Calcific aortic valve disease (CAVD) is a significant cause of illness and death worldwide. Identification of early predictive markers could help optimize patient management. RNA-sequencing was carried out on human fetal aortic valves at gestational weeks 9, 13, and 22 and on a case-control study with adult noncalcified and calcified bicuspid and tricuspid aortic valves. In dimension reduction and clustering analyses, diseased valves tended to cluster with fetal valves at week 9 rather than normal adult valves, suggesting that part of the disease program might be due to reiterated developmental processes. The analysis of groups of coregulated genes revealed predominant immune-metabolic signatures, including innate and adaptive immune responses involving lymphocyte T-cell metabolic adaptation. Cytokine and chemokine signaling, cell migration, and proliferation were all increased in CAVD, whereas oxidative phosphorylation and protein translation were decreased. Discrete immune-metabolic gene signatures were present at fetal stages and increased in adult controls, suggesting that these processes intensify throughout life and heighten in disease. Cellular stress response and neurodegeneration gene signatures were aberrantly expressed in CAVD, pointing to a mechanistic link between chronic inflammation and biological aging. Comparison of the valve RNA-sequencing data set with a case-control study of whole blood transcriptomes from asymptomatic individuals with early aortic valve calcification identified a highly predictive gene signature of CAVD and of moderate aortic valve calcification in overtly healthy individuals. These data deepen and broaden our understanding of the molecular basis of CAVD and identify a peripheral blood gene signature for the early detection of aortic valve calcification.

Development of Tissue Engineered Heart Valves for Percutaneous Transcatheter Delivery in a Fetal Ovine Model

This multidisciplinary work shows the feasibility of replacing the fetal pulmonary valve with a percutaneous, transcatheter, fully biodegradable tissue-engineered heart valve (TEHV), which was studied invitro through accelerated degradation, mechanical, and hemodynamic testing and invivo by implantation into a fetal lamb. The TEHV exhibited only trivial stenosis and regurgitation invitro and no stenosis invivo by echocardiogram. Following implantation, the fetus matured and was delivered at term. Replacing a stenotic fetal valve with a functional TEHV has the potential to interrupt the development of single-ventricle heart disease by restoring proper flow through the heart.

Unusual fetal ascites and spontaneous bladder rupture in a female fetus: a case report

BackgroundFetal bladder rupture causing urinary ascites is uncommon. It is generally related to invasive fetal medicine procedures or obstructive disorders such as in posterior urethral valves in male fetuses. An exceptional case of spontaneous bladder rupture in a female fetus occurred in a pregnant woman treated with high doses of opiates in an intensive care unit. This unusual obstetric situation leads to discussion of the possible causes of fetal bladder rupture, its management, and the pediatric prognosis.Case presentationWe report the case of a 30-year-old nulliparous black woman with a history of mesenteric cystic lymphangioma and multiple bowel resections leading to chronic malabsorption. During her pregnancy, our patient presented with an occlusive syndrome and major bilateral renal dilation. Urinary derivation resulted in iatrogenic bilateral ureteral perforation. Our patient thus presented with major uroperitoneum, bilateral pleural effusion and acute renal failure, treated by thoracic drainage and bilateral nephrostomy. Postoperative pain required treatment with level III analgesics. In this context, 5 days after morphine treatment introduction an enlarged fetal bladder was observed, followed 3 days later by voluminous fetal ascites. The diagnosis of spontaneous bladder rupture was suspected. After multidisciplinary discussion, expectant management was decided. At 31 weeks and 4 days gestation, our patient went into spontaneous labor with a subsequent vaginal delivery. The infant required resuscitation and paracentesis of ascites at birth. Her neonatal course was favorable with a simple urethral bladder drainage. Cystography at day 9 was normal. At 2 years of follow-up, the mother and the child have a normal course.ConclusionsAn iatrogenic origin of megacystis in a female fetus must be evoked in the event of maternal administration of high doses of opiates in the second part of her pregnancy. In our case, the megacystis was followed by spontaneous bladder rupture at 30 weeks of gestation, with a favorable maternal fetal issue.

Fetal Transcatheter Trileaflet Heart Valve Hemodynamics: Implications of Scaling on Valve Mechanics and Turbulence.

The scarcity of data available on the best approach for pulmonary fetal valve replacement or implantation necessitate an investigation on whether practices using adult transcatheter valves could be translated to fetal applications. The objective of this study is to evaluate the hemodynamic characteristics and the turbulent properties of a fetal sized trileaflet transcatheter pulmonary valve in comparison with an adult balloon-expandable valve in order to assess the possibility of designing valves for fetal applications using dynamic similarity. A 6mm fetal trileaflet valve and a 26mm SAPIEN 3valve were assessed in a pulse duplicator. Particle image velocimetry was performed. Pressure gradient (ΔP), effective orifice area (EOA), regurgitant fractions (RF), pinwheeling indices (PI) and turbulent stresses were evaluated. ΔP was 8.56 ± 0.139 and 7.76 ± 0.083mmHg with fetal valve and SAPIEN respectively (p < 0.0001); EOA was 0.10 ± 0.0007 and 2.1 ± 0.025cm2 with fetal valve and SAPIEN respectively (p < 0.0001); RF with the fetal valve was 2.35 ± 1.99% and with SAPIEN 10.92 ± 0.11% (p < 0.0001); PI with fetal valve was 0.404 ± 0.01 and with SAPIEN 0.37 ± 0.07; The flow regime with the fetal valve was turbulent and Reynolds numbers reached about 7000 while those with the SAPIEN reached about 20,000 at peak velocity. Turbulent stresses were significantly higher with fetal valve compared with SAPIEN. Instantaneous viscous shear stresses with fetal valve were 5.8 times higher than those obtained with SAPIEN and Reynolds shear stresses were 2.5 times higher during peak systole. The fetal valve implantation leads to a turbulent flow (specific to this particular type and design of valve) regime unlike what is expected of a small valve with different flow properties compared to adult valves.

Analysis of missed diagnosis of fetal mitral valve diseases by prenatal ultrasound

Objective To summarize the pathology and ultrasonic characteristics of fetal mitral valve diseases and improve their prenatal diagnostic accuracy by ultrasound. Methods Ultrasonic data of fetuses with mitral valve diseases, diagnosed by autopsy from January 2011 to December 2017 in Fetal Heart Disease Maternal Fetal Medicine Research Important Laboratories were retrospectively analyzed. Their ultrasound features and causes of missed diagnosis were analyzed. Results ①The pathologic types included mitral atresia(22 cases, 59.5%), mitral valve dysplasia(13 cases, 35.1%) and mucoid degeneration[2 cases (1 case was diagnosed with Marfan syndrome with dilated aortic sinus and sinus of pulmonary trunk), 5.4%]. ②Fetal ultrasound could detect mitral atresia and mucoid degeneration of mitral valve. There were five cases of mitral valve dysplasia which were missed by ultrasound.And the accuracy rate of ultrasonic diagnosis was 86.5%(32/37). ③The missed subtypes of mitral valve dysplasia included mild-moderate mitral stenosis with coarctation of aorta (4 cases) and mitral valve dysplasia with functional aortic atresia(1 case). Conclusions Fetal mitral valve diseases involve a variety of anatomical abnormalities and the main types are mitral atresia and mitral valve dysplasia. Mucoid degeneration of mitral valve is rare and it may belong to Marfan syndrome when combined with dilated aortic sinus and sinus of pulmonary trunk. Fetal ultrasound can identify mitral atresia and mucoid degeneration of mitral valve, but it may miss the diagnosis of some subtypes of mitral valve dysplasia, such as mild-moderate mitral stenosis with aortic coarctation and mitral valve dysplasia with functional aortic atresia. Key words: Ultrasonography, prenatal; Mitral valve; Fetus

Critical Structural Defects Explain Filamin A Mutations Causing Mitral Valve Dysplasia

Mitral valve diseases affect ∼3% of the population and are the most common reasons for valvular surgery because no drug-based treatments exist. Inheritable genetic mutations have now been established as the cause of mitral valve insufficiency, and four different missense mutations in the filamin A gene (FLNA) have been found in patients suffering from nonsyndromic mitral valve dysplasia (MVD). The filamin A (FLNA) protein is expressed, in particular, in endocardial endothelia during fetal valve morphogenesis and is key in cardiac development. The FLNA-MVD-causing mutations are clustered in the N-terminal region of FLNA. How the mutations in FLNA modify its structure and function has mostly remained elusive. In this study, using NMR spectroscopy and interaction assays, we investigated FLNA-MVD-causing V711D and H743P mutations. Our results clearly indicated that both mutations almost completely destroyed the folding of the FLNA5 domain, where the mutation is located, and also affect the folding of the neighboring FLNA4 domain. The structure of the neighboring FLNA6 domain was not affected by the mutations. These mutations also completely abolish FLNA’s interactions with protein tyrosine phosphatase nonreceptor type 12, which has been suggested to contribute to the pathogenesis of FLNA-MVD. Taken together, our results provide an essential structural and molecular framework for understanding the molecular bases of FLNA-MVD, which is crucial for the development of new therapies to replace surgery.

Evaluation of septal insertion of atrioventricular valves in fetuses by postmortem 4.7 Tesla cardiac MRI: A feasibility study

The purpose of this study was to compare non-invasive high-spatial-resolution postmortem cardiac magnetic resonance imaging (MRI) and autopsy findings for evaluating the septal insertion of atrioventricular valves in fetuses. Five fetal heart specimens including two normal hearts, one heart with complete atrioventricular septal defect (AVSD) and two hearts with linear insertion of atrioventricular valves (LIAVV; gestational age 17 to 34 weeks) were studied with cardiac MRI using a 4.7 T MRI scanner without sample preparation. Three (3D) and two-dimensional (2D) turbo-RARE (rapid imaging with refocused echoes) sequences in four-chamber and left-ventricular long-axis planes were obtained with a minimal isotropic/in-plane resolution of 156μm. Nonparametric tests were performed to compare the distance between insertions of medial leaflets of the atrioventricular valves and the inlet/outlet distance ratio between MRI and autopsy findings in normal, complete AVSD and with linear insertion of atrioventricular valves (LIAVV) fetal hearts. Despite apparent differences between LIAVV/normal hearts, no significant differences were found between differential insertion of medial leaflets and inlet/outlet distance ratios with both techniques. Very good to excellent reliability between both techniques was found for differential insertion (ICC: 87.2%; 95% CI: -21.7%, 99.1%) (P=0.963) and inlet/outlet distance ratio (ICC 98.3%; 95%CI: 85.2%, 99.8%) (P=0.537) measurements. Postmortem cardiac MRI could replace autopsy for assessing normal or abnormal septal insertion of atrioventricular valves in fetuses without requiring specific preparation of the heart.

Z-scores of early diastolic blood flow widths of mitral and tricuspid valves in normal fetuses and fetuses with dilated coronary sinus

Objectives: To establish Z-score models for early diastolic blood flow widths of mitral and tricuspid valves in normal fetuses and compare Z-scores and other blood flow dynamic parameters between normal fetuses and fetuses with dilated coronary sinus (CS). This study seeks to assess whether dilated CS affects cardiac structure or hemodynamics.Methods: One hundred twenty-nine normal fetuses (Group I) and 15 fetuses with dilated CS connected to persistent left superior vena cava (PLSVC) (Group II) were included in this study. Noncardiac biometrical parameters, including gestation age (GA), biparietal diameter (BPD), femoral length (FL), and heart area (HA), were obtained. Hemodynamic parameters, such as the early diastolic blood flow widths of mitral and tricuspid valves (MV-CDFI-Width, TV-CDFI-Width), velocity and time integral of blood flow (VTI), peak early and late diastolic velocity of mitral and tricuspid valves [peak early diastolic velocity of the mitral valve (MVE), peak late diastolic velocity of the mitral valve (MVA), peak early diastolic velocity of the tricuspid valve (TVE), peak late diastolic velocity of the tricuspid valve (TVA)], were measured.Results: Z-score models for MV-CDFI-Width and TV-CDFI-Width against noncardiac biometrical parameters were best described by linear regression analysis. The mean equations of MV-CDFI-Width against noncardiac biometrical parameters were 0.066 + (0.025 × GA), 0.169 + (0.084 × BPD), 0.213 + (0.106 × FL) and 0.533 + (0.028 × HA). The SD for MV-CDFI-Width against FL was estimated based on values from the following equation: −0.006 + (0.02 × FL). Other SDs were constants estimated as the standard deviations of the unscaled residuals. Z-scores and other blood flow dynamic parameters exhibited no statistically significant differences between Group I and Group II.Conclusions: This study demonstrated that dilated CS did not affect fetal hemodynamics of the mitral or tricuspid valves or cardiac structures. We also suggested that the causes of diminutive left heart or coarctation of the aorta might not be associated with dilated CS in fetuses with PLSVC.

Non-syndromic Mitral Valve Dysplasia Mutation Changes the Force Resilience and Interaction of Human Filamin A

Filamin A (FLNa), expressed in endocardial endothelia during fetal valve morphogenesis, is key in cardiac development. Missense mutations in FLNa cause non-syndromic mitral valve dysplasia (FLNA-MVD). Here, we aimed to reveal the currently unknown underlying molecular mechanism behind FLNA-MVD caused by the FLNa P637Q mutation. The solved crystal structure of the FLNa3-5 P637Q revealed that this mutation causes only minor structural changes close to mutation site. These changes were observed to significantly affect FLNa's ability to transmit cellular force and to interact with its binding partner. The performed steered molecular dynamics simulations showed that significantly lower forces are needed to split domains 4 and 5 in FLNA-MVD than with wild-type FLNa. The P637Q mutation wasalso observed to interfere with FLNa's interactions with the protein tyrosine phosphatase PTPN12. Our results provide a crucial step toward understanding the molecular bases behind FLNA-MVD, which is critical for the development of drug-based therapeutics.

Abstract 573: Mechanical Stress Alters Cell Signaling and Extracellular Matrix Genes in Fetal Cardiac Valves

Objective: Prenatal hypertension leads to mitral annular dilation and is linked to changes in valvular extracellular matrix (ECM) and cell cycle genes including TGFβ-1, BMPs and FGF. We hypothesized that these changes are exacerbated by additional mechanical stress. Methods: Fetal sheep received 8 days of plasma infusion to induce hypertension (HTN, n=5) or lactated ringers solution (CTRL, n=4) starting at 126±2 days gestational age (dGA; term~145 days). Fetal mitral valve interstitial cells (VICs) were isolated at 134±1dGA, cultured in flexible, collagen-coated wells and subjected to 0% (static) or 18% equibiaxial stretch (1 Hz, 24 hrs). mRNA was isolated and qPCR was used to determine the effects of HTN and stretch on gene expression. Statistical analysis was performed via two-way ANOVA with Bonferroni correction. Results: Plasma infusion significantly increased the MAP of HTN fetuses (44.3±2.4 vs 61.6±1.1mmHg, p= 0.002). Change in gene expression is shown in Fig. 1; data are expressed relative to the CTRL/static group. Stretch, but not HTN, significantly increased FGF expression (p&lt;0.05). HTN and stretch each significantly increased expression of TGFβ-1, BMP-1 and -2. Stretch amplified the hypertension-induced increase in these 3 genes (p&lt;0.05 for all). Versican was unaltered by HTN or stretch. Conclusion: Our study demonstrates that early exposure to mechanical stress can shape cell signaling pathway responses in developing fetal cardiac valves, and these changes are amplified when exposed to a secondary stress. These data indicate that the prenatal environment has implications for postnatal cardiac valve function and risk for valvular disease in adulthood.

The Transcriptional Signature of Growth in Human Fetal Aortic Valve Development

In the second trimester of human fetal development, a tenfold increase in fetal size occurs while cardiac valves grow and retain their function. Patterns of transcription in normally growing human aortic valves are unknown. Discarded human aortic valve samples were collected from the second trimester, 6 from early (14, 15, 17 weeks) and 6 from late (20, 21, 22 weeks) gestation. Network analysis of RNA sequencing data identified subnetworks of significantly increasing and decreasing transcripts. Subsequent cluster analysis identified patterns of transcription through the time course. Pathway enrichment analysis determined the predominant biological processes at each interval. We observed phasic transcription over the time course, including an early decrease in cell proliferation and developmental genes (14 to 15 weeks). Pattern specification, shear stress, and adaptive immune genes were induced early. Cell adhesion genes were increased from 14 to 20 weeks. A phase involving cell differentiation and apoptosis (17 to 20 weeks) was followed by downregulation of endothelial-to-mesenchymal transformation genes and then by increased extracellular matrix organization and stabilization (20 to 22 weeks). We present a unique data set, comprehensively characterizing human valve development after valve primordia are formed, focusing on key processes displayed by normal aortic valves undergoing significant growth. We build a time course of genes and processes in second trimester fetal valve growth and observe the sequential regulation of gene clusters over time. Critical valve growth genes are potential targets for therapeutic intervention in congenital heart disease and have implications for regenerative medicine and tissue engineering.

Fetal cardiac functional performance and development of diabetic gestations

Objective of research: To reveal and asses probable change in fetal cardiac physiological function of pregestational diabetic gestations. Research design: We performed a prospective research study of 31 gestations between 22 weeks’ gestational age and full term, and who had pregestational diabetes. All diabetic women recruited in the research performed had glycosylated hemoglobin lower than 6.5%. All gestations involved in the research performed had an early sonographic confirmation of fetal gestational age. Doppler study of blood flow via the fetal mitral and tricuspid valves were performed every 4 weeks using a pulsed wave sonographic Doppler machine with a 3.5- or 5-MHz ultrasound transducer. The subsequent parameters were analysed and calculated automatically from the revealed flow velocity waveforms: the peak velocity during the rapid ventricular filling phase (E wave) and during the atrial systole phase (A wave), and the ratio between these obtained velocities (E/A ratio); and the velocity time fundamental of the fetal atrioventricular blood flow (correlated with volume flow). A comparative statistical analysis between the Doppler parameters revealed from fetal examination of diabetic gestations and of normal gestations was performed by using the Mann-Whitney test. Results: Each gestation recruited for the study performed around four to five fetal echocardiographic Sonographic assessments at 22, 26, 30, 34, and 38 weeks’ gestation. The E/A ratio of the mitral and tricuspid valves did not Rise in fetuses of diabetic women during the third trimester and was observed to be statistically significantly higher manner in fetuses of nondiabetic gestations in comparison with fetuses of diabetic gestations at 34 and 38 gestational weeks. Calculated velocity time basic of the mitral and tricuspid valves when multiplied by fetal heart rate was greater, but not statistically significant, in fetuses of nondiabetic gestations when put in comparison with diabetic gestations fetuses at 34 and 38 weeks’ gestational weeks. The E-wave of both the mitral and tricuspid valves rised in both study categories all the way through pregnancy. The A-wave of the mitral and tricuspid valves rised only in diabetic gestation fetuses all over the final gestational trimester and was statistically significant in a greater manner at 34 and 38 gestational weeks compared with fetuses of nondiabetic women. Conclusion: variability in fetal atrioventricular blood flow forms between fetuses of diabetic gestations and normal gestations does not essentially cause variability in fetal functional cardiac compliance.

Unexpected resolution of first-trimester fetal valve stenosis: consequence of developmental remodeling?

Unexpected resolution of first-trimester fetal valve stenosis: consequence of developmental remodeling?

Prenatal Visualization of the Pulmonary and Aortic Valves and Leaflets Is Feasible Using 4‐Dimensional Sonography

The purpose of this study was to determine whether the morphologic characteristics and area of the semilunar valves in healthy fetuses and fetuses with cardiac defects can be visualized by using spatiotemporal image correlation (STIC). Spatiotemporal image correlation volumes from 74 healthy fetuses were recorded in 5 examinations between the 15th and 36th weeks of pregnancy. Second, we recorded STIC volumes from 64 fetuses with various cardiac defects. The quality of the volumes was rated. The areas of the aortic and pulmonary valves were measured in systole by rendering the valves on 4-dimensional sonography. The number of leaflets was examined. Longitudinal data analysis using linear mixed models was performed. Two hundred ninety-three volumes from normal hearts were examined. In 82.5%, the quality of the normal volumes was sufficient. Visualization of the valve opening was feasible in 96.1% of the normal hearts and 97.4% of the abnormal hearts. The success rate of visualization of the pulmonary and aortic valve leaflets was dependent on the gestational age, with the highest percentage (72.1% in normal hearts) at 19 to 24 weeks. Longitudinal regression analysis showed a positive relationship of the aortic and pulmonary valve areas with gestational age (P < .0001) and fetal biometric measurements (P < .0001). Fifty-eight abnormal volumes were examined. Cardiac defects with abnormal valve areas due to aortic and pulmonary stenosis could be clearly visualized by using STIC. Examination of the morphologic characteristics of the semilunar valves using STIC is feasible, which is difficult when using 2-dimensional sonography. With increasing implementation of 4-dimensional sonography, the understanding of rendered images might be useful for anyone practicing fetal echocardiography.

Increased systolic load causes adverse remodeling of fetal aortic and mitral valves.

While abnormal hemodynamic forces alter fetal myocardial growth, little is known about whether such insults affect fetal cardiac valve development. We hypothesized that chronically elevated systolic load would detrimentally alter fetal valve growth. Chronically instrumented fetal sheep received either a continuous infusion of adult sheep plasma to increase fetal blood pressure, or a lactated Ringer's infusion as a volume control beginning on day 126 ± 4 of gestation. After 8 days, mean arterial pressure was higher in the plasma infusion group (63.0 mmHg vs. 41.8 mmHg, P < 0.05). Mitral annular septal-lateral diameter (11.9 mm vs. 9.1 mm, P < 0.05), anterior leaflet length (7.7 mm vs. 6.4 mm, P < 0.05), and posterior leaflet length (P2; 4.0 mm vs. 3.0 mm, P < 0.05) were greater in the elevated load group. mRNA levels of Notch-1, TGF-β2, Wnt-2b, BMP-1, and versican were suppressed in aortic and mitral valve leaflets; elastin and α1 type I collagen mRNA levels were suppressed in the aortic valves only. We conclude that sustained elevated arterial pressure load on the fetal heart valve leads to anatomic remodeling and, surprisingly, suppression of signaling and extracellular matrix genes that are important to valve development. These novel findings have important implications on the developmental origins of valve disease and may have long-term consequences on valve function and durability.