Mitral regurgitation (MR) is the most common valvular disease in the United States affecting over 2% of the population and is expected to double by 2030 due to population aging. MR of any type is a major prognostic factor of mortality: the risk of mortality with severe MR at five years is 36% and even moderate MR nearly doubles the risk of mortality in patients with multiple cardiac comorbidities. In this context, image-based computational simulations can play a key role in understanding MV disease and optimizing transcatheter edge-to-edge repair (TEER) procedures. Moreover, TEER presents a unique challenge in that the device imparts a sustained focal stress on the MV leaflets. Although the long-term consequences of MV TEER is a prevailing clinical concern, these effects have never been studied. For example, we have previously demonstrated that the MV leaflet tissue plastically deforms after myocardial infarction through annular dilation and chordal tethering. These changes in altered mechanical loading have been shown to stimulate shifts in MV biosynthesis at the cellular and molecular levels. Therefore, as TEER induces pronounced focal stress concentrations, we hypothesize that the MV leaflets will undergo substantial plastic deformation post-TEER. To address this hypothesis, we acquired TEE imaging data of patients’ MVs before, immediately after, and 3 months after treatment with TEER to quantify the effects of TEER-induced plastic deformation on MV leaflet function. Our findings not only confirmed the presence of plastic deformation but also offer strong evidence that this plasticity is primarily driven by the TEER procedure itself, rather than other organ-level shifts in loading or boundary conditions. This study emphasizes once again the importance of an individualized approach to MV treatment optimization, but with a holistic focus on all aspects of MV function, with the objective to ensure the best possible long-term outcomes for each patient.

Subaortic stenosis is a congenital heart disease characterised by a narrowing of the left ventricular outflow tract. This is often caused by the presence of a fibrous subaortic membrane (SAM) at the aortic valve inlet. This anatomical obstruction leads to a significant increase in the pressure gradient across the valve/SAM complex inducing haemodynamic alterations, which are not yet fully understood. This research investigates SAM's haemodynamic impact through a combined approach of in vitro tests and computer simulations. Experiments involved placing both rigid and flexible membranes of varying sizes and orientations at the inlet of a bioprosthetic aortic valve. These experiments measured global hydrodynamic parameters and tracked valve dynamics as the SAM orifice area progressively decreased. Complementary particle-based computational modelling provided detailed insights into the resulting haemodynamic effects. The findings indicate that the presence of SAM significantly impairs blood flow when the membrane orifice area is reduced to below 75% of the unobstructed inflow. High-speed video revealed abnormal fluttering of the aortic valve leaflets caused by SAM. Numerical simulations corroborated this, demonstrating the formation and shedding of vortices above the membrane, leading to oscillatory leaflet motion. Stiffness, size and position of the SAM orifice membranes critically affect systolic function and fluttering, with the consequent potential for structural damage and blood complications. This study underscores the importance of considering membrane orifice area and morphology, in addition to the mean pressure gradient, when determining surgical interventions for patients with SAM.

During development, myocardial contractile force and intracardiac hemodynamic shear stress coordinate the initiation of trabeculation. While Snail family genes are well-recognized transcription factors of epithelial-to-mesenchymal transition (EMT), snai1b-positive (+) cardiomyocytes (CMs) are sparsely distributed in the ventricle of zebrafish at 4 days post-fertilization (dpf). Isoproterenol (ISO) treatment significantly increased the number of snai1b+ CMs, of which 80% were Notch-negative. CRISPR-activation of snai1b led to 51.6% CMs forming trabeculae, whereas CRISPR-repression reduced trabecular CMs to 6.7% under ISO. In addition, 36.7% of snai1b-repressed CMs underwent apical delamination. 4-D strain analysis demonstrated that ISO increased the myocardial strain along radial trabecular ridges in alignment with the snai1b expression and Notch-ErbB2-mediated trabeculation. Single-cell and spatial transcriptomics revealed that these snai1b+ CMs were devoid of some EMT-related phenotypes, such as collagen 1a2 production and induction by ErbB2 or TGF-b. Thus, we uncovered snai1b+ CMs that are mechanically activated to initiate delamination for cardiac trabeculation.

Cell behaviour and tissue development are inherently sensitive to morphological features of tissue-engineered scaffolds. Traditionally, imaging techniques such as SEM, TEM, AFM, and CLSM provide high-resolution 2D images to characterise scaffold morphology. However, these techniques have poor penetration and low resolution transversely to the sliced planes. In contrast, synchrotron radiation X-ray micro-computed tomography (SR-µCT) enables 3-D imaging of large volumes with submicron isotropic resolution. We used SR-µCT at beamline I13-2 (Diamond Light Source) to image jet-sprayed nonwoven fibrous scaffolds used in the Harefield Valve, both with and without human adipose-derived stem cells preserved in ethanol to maintain native wet conditions. Large-volume imaging was achieved by stitching 2x2 tiled datasets and reconstructing them into 1 mm³ volumes at 0.325 µm voxel size, enabling clear scaffold. The scaffold exhibited a layered, transversely isotropic structure, with additional in-plane anisotropy observed when using high-speed drum fabrication. SR-µCT revealed significantly higher scaffold porosity compared to SEM analysis, which consistently underestimates porosity due to limited depth and connectivity information. Cell distribution and morphology showed that cells preferentially adhered and proliferated along in-plane structures at full scaffold colonisation. We hypothesise that the cells minimise energy expenditure by expanding in directions of least resistance.

Bicuspid aortic valve (BAV) is the most frequent congenital heart disease, with an incidence of approximately 1%. It can be silent and associated with normal valve function. However, a series of complications, even catastrophic, may occur with time: valve stenosis by dystrophic calcification, infective endocarditis, progressive dilatation of the ascending aorta with valve incompetence, aortic dissection, sudden death. The problem of BAV is not just the number of semilunar cusps. Severe noninflammatory degenerative changes (elastic fibers fragmentation, smooth muscle cells death, mucoid extracellular matrix accumulation) are observed in the aortic wall of BAV patients, with intrinsic weakness accounting for progressive aneurysmal dilatation of the ascending aorta, aortic valve incompetence and aortic dissection. The link between valve and aortic wall pathology finds most probably an explanation in the embryology of the arterial pole, since neurocrestal cells play a role in the development of both the ascending aorta, aortic arch and semilunar valves. The frequent association of adult aortic coarctation with BAV provides evidence for this hypothesis. BAV has a significant genetic component as to require screening of first-degree relatives, like outlined by AHA/ACC 2022 guidelines.

Congenital aortic valve stenosis (AVS) is a severe form of congenital heart disease, accounting for 3–6% of cases. Characterized by malformed aortic valves that obstruct blood flow, AVS can potentially lead to heart failure or death without timely surgical intervention. Current treatments rely on catheter or surgical interventions, often multiple, due to a limited understanding of its molecular basis. To address this gap, we leveraged our Notch1+/-;Gata5-/- AVS mouse model and performed proteomic analysis of aortic valves at postnatal day 10 using HPLC-MS. Our aim was to identify early molecular changes, clinically relevant biomarkers, and potential therapeutic targets. A healthy aortic valve is composed of three distinct extracellular matrix (ECM) layers with valve interstitial cells (VICs) interspersed within them, and valve endothelial cells lining the surface. VICs play a key role in synthesizing ECM components that preserve valve structure and function. We detected significant alterations in 364 proteins, with ~9% involved in ECM organization, supporting impaired valve remodeling in AVS. Notably, integrin proteins, which are associated with TGF-β signaling and ECM remodeling, were significantly elevated in mutant valves and are linked to VIC activation. The additional finding of dysregulated smooth muscle markers suggests aberrant activation driving maladaptive valve thickening. Network analysis further identified CTNNB1 as a potential upstream regulator, suggesting activation of the Wnt signaling pathway, a possible driver of aberrant ECM synthesis. Together, these findings provide insight into early molecular changes in congenital AVS and identify candidate pathways for biomarker development and therapeutic intervention.

Toll-Like Receptors (TLRs) critically link innate immunity with adaptive immunity by recognising membrane components of microorganisms and inducing an inflammatory response. TLRs1-9 have been shown to be expressed in human aortic VICs with TLR2 and TLR4 upregulated in calcified human leaflets. We hypothesise dysregulation of TLR2 and TLR4 in patients with rheumatic heart disease (RHD). 6 normal human aortic and mitral leaflets, 6 aortic and mitral leaflets from RHD and 5 calcified human aortic leaflets were analysed by immunohistochemistry for the spatial expression of TLR2 and TLR4. Flow cytometry assessed expression levels of TLR2 and TLR4, in VIC and VECs, after treatment with bacterial peptides. RHD aortic leaflets showed a significantly reduced expression of TLR4 (p=0.0007) compared to normal and calcified aortic leaflets (p=0.0095). RHD aortic leaflets showed a significantly reduced expression of TLR2 (p=0.0087) compared to normal and calcified aortic leaflets (p=0.0043). Mitral RHD leaflets showed a similar pattern to aortic RHD leaflets in that they showed significantly reduced level of expression of TLR4 (p=0.029) and TLR2 (p=0.0087) compared to normals. Lipoteich acid decreased whereas lipopolysaccharide (LPS) increased the incidence of TLR4+ve VICs. LPS treatment decreased the incidence of TLR2+ve VECs. A significantly reduced expression of TLR2 and TLR4 in aortic and mitral leaflets from RHD patients suggests there may be a compensatory mechanism in RHD patients to limit inflammation. Additional factors that reduce the expression of TLR2 and TLR4 in human VICs and VECs are being investigated.

The tricuspid aortic valve (AoV) comprises three cusps—left coronary (LCC), right coronary (RCC), and non-coronary (NCC)—that experience distinct hemodynamic environments, cellular distributions, and pathological susceptibilities. While the NCC consistently bears the highest calcific burden in calcific aortic valve disease (CAVD), the basis for this asymmetry remains poorly defined. Here, we investigated whether anatomical, hemodynamic, extracellular matrix (ECM), and transcriptomic differences contribute to asymmetric cusp remodeling and congenital bicuspid AoV (BAV) malformations. Using a chronic kidney disease-induced mouse model of CAVD, we found no correlation between coronary ostium position and calcification burden. Instead, NCCs showed significantly greater calcification than LCCs, despite comparable or even lower wall shear stress. ECM analysis revealed that LCCs contain more elastin and collagen than NCCs or RCCs, yet these properties did not predict the observed asymmetry in calcification. Spatial transcriptomics demonstrated distinct gene expression profiles across cusps, with the LCC showing downregulation of melanocytic genes (Dct, Tyrp1, Pmel) and the NCC enriched in pro-calcific and contractile markers (Myh11, Palmd). These findings suggest that differential embryonic cell infiltration—particularly cardiac neural crest and second heart field populations—may impart lasting regional phenotypic differences. Additionally, genetic loss of melanocytic pigmentation reduced both BAV penetrance and calcification in eNOS-deficient mice, further implicating pigment-producing cells in AoV development and disease. Together, these results highlight the critical role of asymmetric cellular composition in driving cusp-specific vulnerability to calcification and congenital malformation, offering new insights into non-mechanical contributors to AoV pathophysiology.

Cardiovascular diseases, especially rheumatic heart disease (RHD), are a leading cause of maternal morbidity and mortality in Egypt, where fragmented care and limited specialist access heighten pregnancy risks. General obstetric units often lack the expertise to manage complex heart conditions, leading to delayed diagnosis, inadequate treatment, and preventable adverse maternal and fetal outcomes. The Aswan Heart Centre’s cardio-obstetric care (CO-care) program addresses this gap by integrating cardiology, obstetrics, and nursing to deliver protocol-driven, risk-stratified care for high-risk pregnancies, focusing on early detection and management of primary and secondary cardiovascular complications during and after pregnancy. Pregnant females with primary cardiovascular complications of pregnancy or history of pre-existing cardiovascular disease and/ or intervention are accepted both on self-referrals and referrals from other healthcare providers, offering long-term follow-up and maintaining a registry to track outcomes and late cardiovascular complications. Key implementation steps include raising provider awareness to patients and health care providers, standardizing protocols, ensuring access to counseling and specialized diagnostics, and building referral networks. Expected outcomes are improved maternal survival, reduced preterm births, and a scalable, sustainable model for cardio-obstetric care that can be adapted in other low- and middle-income countries facing similar challenges.

There is growing recognition in regenerative cardiovascular tissue engineering that transmural vessel ingrowth is the predominant—if not exclusive—mechanism for achieving in-situ endothelialization in prosthetic vascular grafts and heart valves in humans This process requires continuous ingrowth channels with dimensions sufficient to accommodate capillaries or even arterioles. While a variety of methods—such as electrospinning—exist to create porous scaffolds, current characterization techniques fail to determine whether the resulting structures offer well-defined and consistently continuous ingrowth spaces. Drawing on principles from geological porous media research, we applied a combination of nano-computer-tomography, deep-learning segmentation and super-resolution algorithms, and pore network modelling, to characterize the full thickness pore space morphology of electrospun scaffolds. Scaffolds were non-destructively reconstructed at high resolution (0.54 microns) and large fields of view, 57x faster than a brute-force approach, achieving total sample volumes greater than 1x108 um3 in just a few hours. Electrospun scaffolds showed a median pore size and median pore volume of 5.51um (IQR: 5.15)/418.07um2 (IQR: 1153.74), n = 15 698, for the 16% polymer weight percentage group; 5.40um (IQR: 6.23)/412.24um2 (IQR: 1485.24), n = 13 437, for 18%; and 5.40um (IQR: 4.22)/356.34um2 (IQR: 826.53), n = 28 620, for 20%. On deeper analysis, continuous, interconnected pore networks of <10 microns in minimum diameter were extracted, with the 18% group showcasing the most extensive, surface-to-surface networking. This analysis highlights the limited ability of single-needle electrospinning to produce sufficient growth space for reliable transmural capillary endothelialisation. With the advent of cutting-edge additive and reductive manufacturing techniques, alternative methods for porous scaffold construction show promise.