Altitude as a key environmental factor shaping microbial communities of tea green leafhoppers (Matsumurasca onukii).

IMPORTANCE: Host-associated microbial communities play an important role in the fitness of insect hosts. However, the factors shaping microbial communities in wild populations, including environmental factors and interactions among microbial species, remain largely unknown. The tea green leafhopper has a wide geographical distribution and is highly adaptable, providing a suitable model for studying the effect of ecological drivers on microbiomes. This is the first large-scale culture-independent study investigating the microbial communities of M. onukii sampled from different locations. Altitude as a key environmental factor may have shaped microbial communities of M. onukii by affecting the relative abundance of endosymbionts, especially Wolbachia. The results of this study, therefore, offer not only an in-depth view of the microbial diversity of this species but also an insight into the influence of environmental factors.

A functionalized biological heart valve by double bond crosslinking with enhanced biocompatibility and antithrombogenicity.

With the advancement of minimally invasive interventional therapy, biological heart valves (BHVs) have been extensively used in clinics. However, BHVs are generally prone to degeneration within 10-15 years after implantation due to defects including cytotoxicity, immune response, calcification and thrombosis, which are closely related to glutaraldehyde-crosslinking. In this work, we prepared a functionalized BHV through the in situ polymerization of methacrylated porcine pericardium and 2-hydroxyethyl methacrylate to avoid and overcome the defects of glutaraldehyde-crosslinked BHVs. The functionalized BHV was proven to be stable against enzymatic degradation and compatible towards HUVECs. After implantation in rats subcutaneously, a significantly mitigated immune response and reduced calcification were observed in the functionalized BHV. With the grafting of hydrophilic 2-hydroxyethyl methacrylate polymers, the antithrombogenicity of BHV was markedly enhanced by resisting the unfavorable adhesion of blood components. Moreover, the hydrodynamics of the functionalized BHV totally conformed to ISO 5840-3 under a wide range of simulated physiological conditions. These results indicate that the functionalized BHV with enhanced biocompatibility, anticalcification property and antithrombogenicity exhibited a low risk of degeneration and should be explored for further application.

Poly(2-methoxyethyl acrylate) coated bioprosthetic heart valves by copolymerization with enhanced anticoagulant, anti-inflammatory, and anti-calcification properties.

Commercial glutaraldehyde (Glut) cross-linked bioprosthetic heart valves (BHVs) fabricated from the pericardium have become the most popular choice for treating heart valve diseases. Nevertheless, thrombosis, inflammation and calcification might lead to structural valve degeneration (SVD), which limited the durability of BHVs. Herein, to improve the biocompatibility of BHVs, we fabricated a poly-(2-methoxyethyl acrylate) (PMEA) coated porcine pericardium (PMEA-PP) through grafting PMEA to the porcine pericardium (PP) that was pre-treated with Glut and methacrylated polylysine. PMEA coating mitigated the side effects caused by aldehyde residues. It was shown that the PMEA coating reduced cytotoxicity and inflammation reactions and improved endothelialization potential, and its hydrophilic surface improved the anti-thrombotic properties of PPs. And the PMEA coating significantly reduced the calcification of PPs. This strategy promoted the endothelialization potential and improve the anti-thrombosis and anti-calcification properties of BHVs, and is expected to overcome the defects of commercial BHVs.

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.

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.

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.

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.

A Multistrategy-Integrated Learning Sparrow Search Algorithm and Optimization of Engineering Problems.

The swarm intelligence algorithm is a new technology proposed by researchers inspired by the biological behavior of nature, which has been practically applied in various fields. As a kind of swarm intelligence algorithm, the newly proposed sparrow search algorithm has attracted extensive attention due to its strong optimization ability. Aiming at the problem that it is easy to fall into local optimum, this paper proposes an improved sparrow search algorithm (IHSSA) that combines infinitely folded iterative chaotic mapping (ICMIC) and hybrid reverse learning strategy. In the population initialization stage, the improved ICMIC strategy is combined to increase the distribution breadth of the population and improve the quality of the initial solution. In the finder update stage, a reverse learning strategy based on the lens imaging principle is utilized to update the group of discoverers with high fitness, while the generalized reverse learning strategy is used to update the current global worst solution in the joiner update stage. To balance exploration and exploitation capabilities, crossover strategy is joined to update scout positions. 14 common test functions are selected for experiments, and the Wilcoxon rank sum test method is achieved to verify the effect of the algorithm, which proves that IHSSA has higher accuracy and better convergence performance to obtain solutions than 9 algorithms such as WOA, GWO, PSO, TLBO, and SSA variants. Finally, the IHSSA algorithm is applied to three constrained engineering optimization problems, and satisfactory results are held, which proves the effectiveness and feasibility of the improved algorithm.

Subpopulation Particle Swarm Optimization with a Hybrid Mutation Strategy.

With the large-scale optimization problems in the real world becoming more and more complex, they also require different optimization algorithms to keep pace with the times. Particle swarm optimization algorithm is a good tool that has been proved to deal with various optimization problems. Conventional particle swarm optimization algorithms learn from two particles, namely, the best position of the current particle and the best position of all particles. This particle swarm optimization algorithm is simple to implement, simple, and easy to understand, but it has a fatal defect. It is hard to find the global optimal solution quickly and accurately. In order to deal with these defects of standard particle swarm optimization, this paper proposes a particle swarm optimization algorithm (SHMPSO) based on the hybrid strategy of seed swarm optimization (using codes available from https://gitee.com/mr-xie123234/code/tree/master/). In SHMPSO, a subpopulation coevolution particle swarm optimization algorithm is adopted. In SHMPSO, an elastic candidate-based strategy is used to find a candidate and realize information sharing and coevolution among populations. The mean dimension learning strategy can be used to make the population converge faster and improve the solution accuracy of SHMPSO. Twenty-one benchmark functions and six industries-recognized particle swarm optimization variants are used to verify the advantages of SHMPSO. The experimental results show that SHMPSO has good convergence speed and good robustness and can obtain high-precision solutions.

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.

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.

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.

Pre-mounted dry TAVI valve with improved endothelialization potential using REDV-loaded PEGMA hydrogel hybrid pericardium.

The pre-mounted dry transcatheter aortic valve implantation (TAVI) valve is a new technology in the development of biological heart valves. Dry valves do not need to be placed in special preservation solution and can be opened and used immediately, meeting the needs of clinical emergency valve implantation. However, current biological valves obtained by simple air drying cannot be unfolded quickly. In addition, the crimping process leads to structural damage to the valve fiber microstructure, reducing the service life of biological valves. Furthermore, current biological valves still have problems such as calcification, endothelialization difficulty, and immune rejection. In this study, a poly(ethylene glycol)methacrylate (PEGMA) hydrogel hybrid pericardium loaded with REDV was developed. The PEGMA monomer solution can penetrate the space of the pericardium. REDV was loaded into the PEGMA hydrogel, which was hybridized with pericardium via in situ polymerization. The results showed improved unfolding properties, less mechanical damage after crimping, and improved endothelialization potential of the biological valve. Thus, REDV-loaded PEGMA hydrogel hybrid pericardium is a promising approach for obtaining pre-mounted dry TAVI valves with enhanced endothelialization properties.