Biomimetic-modified bioprosthetic heart valves with Cysteine-Alanine-Glycine peptide for anti-thrombotic, endothelialization and anti-calcification.

In recent years, bioprosthetic heart valves (BHVs) prepared by cross-linking porcine or bovine pericardium with glutaraldehyde (Glut) have received widespread attention due to their excellent hemocompatibility and hydrodynamic properties. However, the failure of BHVs induced by thrombosis and difficulty in endothelialization still exists in clinical practice. Improving the biocompatibility and endothelialization potential of BHVs is conducive to promoting their anti-thrombosis properties and prolonging their service life. Herein, Cysteine-Alanine-Glycine (CAG) peptide was introduced into the biomimetic BHV materials modified by 2-methacryloyloxyethyl phosphorylcholine (MPC) to improve their anti-thrombosis and promoting-endothelialization performances. MPC can improve the anti-adsorption performance of BHV materials, as well as, CAG contributes to the adhesion and proliferation of endothelial cells on the surface of BHV materials. The results of experiments showed that the biomimetic modification strategy with MPC and CAG reduce the thrombosis of BHV materials and improve their endothelialization in vitro. More importantly, the calcification of BHV significantly reduced by inhibiting the expression of M1 macrophage-related factors (IL-6, iNOS) and promoting the expression of M2 macrophage-related factors (IL-10, CD206). We believe that the valve-modified strategy is expected to provide effective solutions to clinical valve problems.

Dual-crosslinked bioprosthetic heart valves prepared by glutaraldehyde crosslinked pericardium and poly-2-hydroxyethyl methacrylate exhibited improved antithrombogenicity and anticalcification properties.

Bioprosthetic heart valves (BHVs) have been widely used due to the revolutionary transcatheter aortic valve replacement (TAVR) techniques but suffer from a limited lifespan. Previous modification methods of BHVs mainly rely on glutaraldehyde precrosslinking and subsequent modification. In this study, we have engineered a Poly-2-Hydroxyethyl methacrylate (pHEMA) coated BHV based on co-crosslinking and co-polymerization strategies. Our BHV overcomes previous limitations of glutaraldehyde prefixation by introducing free molecules before crosslinking to achieve the crosslinking and allyl moiety immobilization simultaneously. Decellularized porcine pericardium and 2-Amino-4-pentenoic acid (APA) are firstly co-crosslinked by glutaraldehyde to obtain alkenylated porcine pericardium (APA-PP), then APA-PP is copolymerized with hydrophilic monomer 2-Hydroxyethyl methacrylate (HEMA) to prepare pHEMA grafted porcine pericardium (HEMA-PP). Compared with traditional glutaraldehyde crosslinked pericardium (GA), HEMA-PP exhibits decreased cytotoxicity and significantly increased endothelialial cells proliferation (7-folds higher than GA after 3-day incubation). In vitro and ex vivo hemocompatibility studies demonstrate the superiority of HEMA-PP in anti-thrombogenicity, where the platelet adhesion decreased by levels of approximately 89% compared to GA. Moreover, HEMA-PP maintains structurally stable with a low level of calcification in the subcutaneous model. The hydrodynamic performance and durability are proven to meet the requirements of ISO 5840-3. Altogether, HEMA-PP may have the potential for future clinical application. STATEMENT OF SIGNIFICANCE: Currently, bioprosthetic heart valves (BHVs) have drawbacks including cytotoxicity, calcification and thrombosis, which would accelerate structural valvular degeneration and limit the service life of BHVs. We developed a new modification strategy that could simultaneously improve the biocompatibility, anti-calcification and anti-thrombotic properties of BHVs. Moreover, the appropriate durability and hydrodynamic property demonstrated the potential of our strategy for clinical application. This work will potentially prolong the service life of BHVs and provide new insight for the modification of BHVs.

Arginine-grafted porcine pericardium by copolymerization to improve the cytocompatibility, hemocompatibility and anti-calcification properties of bioprosthetic heart valve materials.

Bioprosthetic heart valves (BHVs) have been used widely due to the development of transcatheter heart valve replacement technology. However, glutaraldehyde crosslinked pericardium (GA), which is widely used as a leaflet material for BHVs, still has disadvantages, including cytotoxicity, thrombosis, and calcification, which lead to the dysfunction and degeneration of BHVs. Herein, we prepared a methacrylated arginine-grafted BHV through the copolymerization of methacrylated arginine and methacrylated porcine pericardium (PP). Briefly, PP was crosslinked by glutaraldehyde and methacrylated polylysine (pLy-MA) to obtain methacrylated PP (pLy-GA), and the pLy-GA was then copolymerized with methacrylated arginine to prepare methacrylated arginine-grafted PP (pLy-GA-Arg). The introduction of Arg-MA improved the ability of PP to resist platelet adhesion, and compared with GA, platelet adhesion decreased by 78% which exhibited improved antithrombotic properties. pLy-GA-Arg exhibited improved cytocompatibility and the relative proliferation rate of HUVECs increased by 2 times compared with GA. After 60 days of subcutaneous implantation, the calcification degree of pLy-GA-Arg was significantly lower than that of GA (4.37 ± 0.33 µg mg-1versus 157.46 ± 41.74 µg mg-1). The introduction of arginine improved the hemocompatibility and cytocompatibility of PP and reduced its calcification, offering a potential option for BHV fabrication in the future.

Hyaluronic Acid-Grafted Bioprosthetic Heart Valves Achieved by Copolymerization Exhibited Improved Anticalcification and Antithrombogenicity.

Bioprosthetic heart valves (BHVs) are widely used in clinic, but they still have problems of calcification, thrombogenicity, and cytotoxicity. The reported techniques based on glutaraldehyde (Glut) crosslinking have difficulty in solving these problems simultaneously. In this study, we grafted Glut-crosslinked porcine pericardium (GA) with hyaluronic acid (HA) by radical copolymerization to improve its anticalcification and antithrombotic properties. Partially methacrylated poly-ε-lysine was used to introduce methacryl groups into GA. Then, HA-grafted porcine pericardium (GA-HA) was obtained by radical copolymerization. Rat's subcutaneous implantation results showed that the calcium content of GA-HA was significantly lower than that of GA (37 ± 29 µg/mg vs 188 ± 7 µg/mg), and the platelets adhering to the surface of GA-HA decreased by approximately 41% compared with GA. In conclusion, grafting porcine pericardium with HA by copolymerization might be feasible to improve the anticalcification and antithrombotic properties of BHVs.

A PEGylation method of fabricating bioprosthetic heart valves based on glutaraldehyde and 2-amino-4-pentenoic acid co-crosslinking with improved antithrombogenicity and cytocompatibility.

With the development of diagnostic techniques, the incidence of bioprosthetic heart valve thrombosis (BHVT) is found to be seriously underestimated. Developing bioprosthetic heart valves (BHVs) that have good hemocompatibility without sacrificing other properties such as hydrodynamics and durability will be an effective strategy to alleviate BHVT. In this study, we developed a PEGylation method by co-crosslinking and subsequent radical polymerization. 2-amino-4-pentenoic acid was used to introduce carbon-carbon double bonds for glutaraldehyde crosslinked pericardia. Then poly (ethylene glycol) diacrylate (PEGDA) was immobilized on pericardia by radical polymerization. A comprehensive evaluation of the modified pericardia was performed including structural characterization, hemocompatibility, cytocompatibility, mechanical properties, component stability, hydrodynamic performance and durability of the BHVs. The modified pericardia significantly reduced platelet adhesion by more than 75% compared with traditional glutaraldehyde crosslinked pericardia. Cell viability in the modified pericardia group was nearly 5-fold higher than that in glutaraldehyde crosslinked pericardia. The hydrodynamic performance met the requirements of ISO 5840-3 under physiological aortic valve conditions and its durability was proved after 200 million cycles of accelerated fatigue test. In conclusion, PEGDA modified pericardia exhibited improved antithrombogenicity and cytocompatibility properties compared with glutaraldehyde crosslinked pericardia. STATEMENT OF SIGNIFICANCE: Bioprosthetic valve (BHV) implantation requires BHV to be structurally stable as well as biocompatible in vivo. Traditional glutaraldehyde crosslinking method prepared BHV suffers from severe cytotoxicity, thrombosis, and calcification. BHV modification methods that have simultaneously improved structural stability and biocompatibility were rarely reported. Here, we proposed a PEGylation method for BHV based on co-crosslinking strategy that could improve its structural stability as well as hemocompatibility. We take the advantage of high efficiency of glutaraldehyde crosslinking and demonstrate the feasibility and superiority of the PEGylated strategy, offering a promising option in glutaraldehyde-based BHV fabrication in the future.

Multiplexed nanomaterial-assisted laser desorption/ionization for pan-cancer diagnosis and classification.

As cancer is increasingly considered a metabolic disorder, it is postulated that serum metabolite profiling can be a viable approach for detecting the presence of cancer. By multiplexing mass spectrometry fingerprints from two independent nanostructured matrixes through machine learning for highly sensitive detection and high throughput analysis, we report a laser desorption/ionization (LDI) mass spectrometry-based liquid biopsy for pan-cancer screening and classification. The Multiplexed Nanomaterial-Assisted LDI for Cancer Identification (MNALCI) is applied in 1,183 individuals that include 233 healthy controls and 950 patients with liver, lung, pancreatic, colorectal, gastric, thyroid cancers from two independent cohorts. MNALCI demonstrates 93% sensitivity at 91% specificity for distinguishing cancers from healthy controls in the internal validation cohort, and 84% sensitivity at 84% specificity in the external validation cohort, with up to eight metabolite biomarkers identified. In addition, across those six different cancers, the overall accuracy for identifying the tumor tissue of origin is 92% in the internal validation cohort and 85% in the external validation cohort. The excellent accuracy and minimum sample consumption make the high throughput assay a promising solution for non-invasive cancer diagnosis.

A hydrophobic antifouling surface coating on bioprosthetic heart valves for enhanced antithrombogenicity.

Thrombosis is an important factor that causes the failure of artificial biological valves in addition to calcification and immune rejection. A hydrophobic antifouling surface can improve blood compatibility by reducing the absorption of protein. In this study, porcine pericardium was cross-linked with glycidyl methacrylate, and carbon-carbon double bonds were introduced. Then, fluoride monomer was added so that the pericardial surface would become hydrophobic and antifouling. Fluoride modification changed the hydrophilicity of the pericardium surface, and the surface water contact angle increased from 84° to 143°. Compared with unmodified pericardium, the adsorption of bovine serum albumin and fibrinogen decreased by 93.1% and 85%, respectively, and the anti-thrombogenicity was greatly enhanced.

Glycidyl methacrylate-crosslinked fish swim bladder as a novel cardiovascular biomaterial with improved antithrombotic and anticalcification properties.

At present, commercial artificial biological valves are mostly prepared by crosslinking bovine or porcine pericardia with glutaraldehyde. Swim bladder has similar components and lower immunogenicity compared to bovine or porcine pericardium. In this study, we used a glycidyl methacrylate (GMA)-based radical polymerization method to crosslink decellularized swim bladders. Amino and carboxyl groups in the swim bladder were reacted with epoxy groups on GMA to introduce carbon-carbon double bonds to the swim bladder. The results showed that the platelet adhesion of GMA-crosslinked swim bladders (GMA-SBs) decreased by 35%, as compared to that of glutaraldehyde-crosslinked swim bladders (GLUT-SBs). Moreover, the superior anticoagulant property was further verified by the ex vivo arteriovenous shunt assay. Meanwhile, the subcutaneous implantation in rats showed that GMA-SBs were able to effectively inhibit the calcification compared with GLUT-SBs. In conclusion, GMA-SBs showed improved antithrombotic and anticalcification properties compared to GLUT-SBs.

Cross-Linking Porcine Pericardium by 3,4-Dihydroxybenzaldehyde: A Novel Method to Improve the Biocompatibility of Bioprosthetic Valve.

Heart valve replacement is an effective therapy for patients with moderate to severe valvular stenosis or regurgitation. Most bioprosthetic heart valves applied clinically are based on cross-linking with glutaraldehyde (GLUT), but they have some drawbacks like high cytotoxicity, severe calcification, and poor hemocompatibility. In this study, we focused on enhancing the properties of bioprosthetic heart valves by cross-linking with 3,4-dihydroxybenzaldehyde (DHBA). The experiment results revealed that compared with GLUT cross-linked porcine pericardium (PP), the relative amount of platelets absorbed on the surface of DHBA cross-linked PP decreased from 0.294 ± 0.034 to 0.176 ± 0.028, and the activated partial thromboplastin time (APTT) increased from 9.9 ± 0.1 to 15.2 ± 0.1 s, indicating improved hemocompatibility. Moreover, anticalcification performance and cytocompatibility were greatly enhanced by DHBA cross-linking. In conclusion, the properties of bioprosthetic valves could be effectively improved by processing valves with a DHBA-based cross-linking method.

The extracellular matrix enriched with membrane metalloendopeptidase and insulin-degrading enzyme suppresses the deposition of amyloid-beta peptide in Alzheimer's disease cell models.

Amyloid plaque is a typical feature of Alzheimer's disease (AD) and is one of the targets for AD therapy. Membrane metalloendopeptidase (MME) and insulin-degrading enzyme (IDE) are two types of proteases that could cleave beta-amyloid (Aß) peptides generated by neuron cells of AD patients. Extracellular matrix (ECM) plays a crucial role in regulating tissue-specific functions and is an ideal biomaterial for tissue repair. In this study, we extracted the liquid ECM enriched with collagen-binding-domain-fused IDE or MME from human foreskin fibroblast cells. We found that these ECM biomaterials reduced the aggregation of Aß peptides, prevented the formation of amyloid plaques, and also suppressed phosphorylation of Tau protein in AD cell models. Overall, our research provides a novel ECM biomaterial that can be potentially used for AD therapy.