Sulfonated, oxidized pectin-based double crosslinked bioprosthetic valve leaflets for synergistically enhancing hemocompatibility and cytocompatibility and reducing calcification

Comprehensive genetic analysis based on multi - omics reveals novel therapeutic targets for mitral valve prolapse and drug molecular dynamics simulation

OBJECTIVE

Mitral valve prolapse (MVP), the most prevalent primary valvular disease, serves as a direct risk factor for multiple cardiovascular disorders and exhibits a high prevalence in the general population. As no specific pharmacological therapies currently exist for MVP, the identification of precise therapeutic targets is imperative.

METHOD

We conducted comprehensive causal genetic inference by integrating genetic data from expression quantitative trait loci (eQTL) and genome-wide association studies (GWAS). Analytical approaches included Mendelian Randomization (MR), colocalization analysis, Summary-data-based Mendelian Randomization (SMR), Linkage Disequilibrium Score Regression (LDSC), and High-Definition Likelihood (HDL) analysis. Protein quantitative trait loci (pQTL) were utilized to validate gene expression. Replication analyses were performed using additional exposure datasets. Methylation quantitative trait loci (mQTL) were employed to elucidate regulatory roles of methylation sites on genes and disease pathogenesis. Phenome-Wide Association Study (PheWAS) was conducted to predict potential adverse effects of gene-targeted therapies. Drug candidates targeting identified genes were predicted via the Drug Signature Database (DSigDB) and validated through molecular docking. Core targets were identified using the STRING database, followed by molecular dynamics simulations.

RESULT

Two-sample MR analysis showed that genetically predicted 266 genes had positive or negative causal relationships with MVP. Colocalization analysis indicated that 9 genes had a posterior probability greater than 0.75. Subsequent SMR analysis excluded the gene GAPVD1. HDL analysis showed that except for the gene PTPN1, the remaining 7 genes were all significantly genetically associated with MVP, and LDSC analysis further showed that only NMB was associated with MVP. Validation using pQTL data confirmed that increased NMB protein expression reduced the risk of MVP. Replication analysis further verified this conclusion. In addition, SMR analysis of methylation sites for 8 genes indicated that multiple methylation sites played a key role in gene regulation of mitral valve prolapse. PheWAS results showed that targeted therapy for 8 genes did not detect other causal associations at the genome-wide significance level. Molecular docking showed that quercetin had good binding ability with 8 target genes. The STRING database identified 3 core target proteins, and molecular dynamics simulations further verified the binding ability of quercetin with core target proteins.

CONCLUSION

This study successfully predicted the potential of multiple druggable genes as effective therapeutic targets for MVP through genetic methods, validated the potential of quercetin as a drug, and provided new ideas for drug treatment strategies for MVP.

Performance characterization and biocompatibility assessment of silicone polyurethanes for polymer heart valve applications

Silicone polyurethanes have gained widespread application in the biomedical field due to their excellent biocompatibility. This study comprehensively investigates four silicone polyurethane materials suitable for polymer heart valves, each exhibiting distinct chemical compositions and structural characteristics, leading to significant differences, particularly in mechanical performance and biocompatibility. Surface analysis reveals an elevated surface silicon element content in all materials compared to the bulk, indicating a migration of silicon elements towards the surface, providing a structural basis for enhancing biological stability and biocompatibility. However, higher silicon content leads to a decrease in mechanical performance, potentially resulting in mechanical failure and rupture in artificial heart valves. Concerning biocompatibility, an increase in silicone content diminishes the material's adsorption capability for cells and proteins, consequently improving its biocompatibility and biological stability. In summary, while high silicone content leads to a reduction in mechanical performance, the formation of a "silicon protective layer" on the material surface mitigates cell and protein adsorption, thereby enhancing biocompatibility and biological stability. Through comprehensive testing of the four silicone polyurethane materials, this study aims to provide insightful perspectives and methods for selecting materials suitable for polymer heart valves. Additionally, the thorough performance exploration of these materials serves as a crucial reference for the performance assessment and biocompatibility research of polymeric artificial heart valve materials.

A polyurethane-based hydrophilic elastomer with multi-biological functions for small-diameter vascular grafts

Thrombosis and intimal hyperplasia (IH) are two major problems faced by the small-diameter vascular grafts. Mimicking the native endothelium and physiological elasticity of blood vessels is considered an ideal strategy. Polyurethane (PU) is suitable for vascular grafts in mechanics because of its molecular designability and elasticity; however, it generally lacks the endothelium-like biofunctions and hydrophilicity. To solve this contradiction, a hydrophilic PU elastomer is developed by crosslinking the hydrophobic hard-segment chains containing diselenide with diaminopyrimidine-capped polyethylene glycol (PEG). In this network, the hydrophobic aggregation occurs underwater due to the uninterrupted hard-segment chains, leading to a significant self-enhancement in mechanics, which can be tailored to the elasticity similar to natural vessels by adjusting the crosslinking density. A series of in vitro studies confirm that the hydrophilicity of PEG and biological activities of aminopyrimidine and diselenide give the PU multi-biological functions similar to the native endothelium, including stable catalytic release of nitric oxide (NO) in the physiological level; anti-adhesion and anti-activation of platelets; inhibition of migration, adhesion, and proliferation of smooth muscle cells (SMCs); and antibacterial effect. In vivo studies further prove the good histocompatibility with both significant reduction in immune response and calcium deposition. STATEMENT OF SIGNIFICANCE: Constructing small-diameter vascular grafts similar to the natural vessels is considered an ideal method to solve the restenosis caused by thrombosis and intimal hyperplasia (IH). Because of the long-term stability, bulk modification is more suitable for implanted materials, however, how to achieve the biofunctions, hydrophilicity, and elasticity simultaneously is still a big challenge. In this work, a kind of polyurethane-based elastomer has been designed and prepared by crosslinking the functional long hard-segment chains with PEG soft segments. The underwater elasticity based on hydration-induced stiffening and the multi-biological functions similar to the native endothelium are compatible with natural vessels. Both in vitro and in vivo experiments demonstrate the potential of this PU as small-diameter vascular grafts.

Surface modification strategies for improved hemocompatibility of polymeric materials: a comprehensive review

Polymeric biomaterials are a widely used class of materials due to their versatile properties. However, as with all other types of materials used for biomaterials, polymers also have to interact with blood. When blood comes into contact with any foreign body, it initiates a cascade which leads to platelet activation and blood coagulation. The implant surface also has to encounter a thromboinflammatory response which makes the implant integrity vulnerable, this leads to blood coagulation on the implant and obstructs it from performing its function. Hence, the surface plays a pivotal role in the design and application of biomaterials. In particular, the surface properties of biomaterials are responsible for biocompatibility with biological systems and hemocompatibility. This review provides a report on recent advances in the field of surface modification approaches for improved hemocompatibility. We focus on the surface properties of polysaccharides, proteins, and synthetic polymers. The blood coagulation cascade has been discussed and blood - material surface interactions have also been explained. The interactions of blood proteins and cells with polymeric material surfaces have been discussed. Moreover, the benefits as well as drawbacks of blood coagulation on the implant surface for wound healing purposes have also been studied. Surface modifications implemented by other researchers to enhance as well as prevent blood coagulation have also been analyzed.