Study on Protein Nanomarker Combined with Vascular Endothelial Growth Factor to Improve Vascularization of Rabbit Urethral Defect Tissue Engineering

To construct the tissue engineering urethral material that is closest to the normal urethral structure in the true sense in vitro. Abdominal ADSC from a 2-month-old New Zealand white rabbit was extracted and directly compounded with non-woven polyglycolic acid (PGA) (control group) to induce the differentiation of myoblasts and epithelial-like cells in vitro and shaped into urethral structure lumen Observation group); After Gd chelating protein nano-labeling and VEGF-loaded sustained release, the rabbit model of a long urethral defect was replanted and cultured for 4 weeks, 8 weeks and 12 weeks, respectively. There was no difference in urinary tract patency rate, urinary tract infection, and renal dysfunction rate between the two groups (P > 0.05). The urine flow rate in the observation group was significantly higher than that in the control group, and the residual volume decreased (P < 0.05). The blood vessel density and CD31 percentage in the observation group increased (P < 0.05). Compared with the conventional ADSC directly in contact with the composite material to construct the urethra, in vitro induction of ADSC to myoblasts and epithelial-like cells respectively, and then use the cell membrane technology to build a tissue engineering urethral material that is closest to the normal urethral structure in the true sense, and loaded with VEGF Loop release technology can significantly improve urodynamic functions, optimize tissue engineering urethral structure and vascularization, and is expected to become a new technology for constructing new tissue engineering urethral materials.

Biocompatibility of electrospinning polycaprolactone, polylactic acid, their blends and copolymers scaffolds in in vitro tests if mesenchyme stem cells

Background. Biodegradable polymers are one of the most promising groups of materials suitable for creating tissue-engineered scaffolds. The high interest in biopolymers is associated with the possibility of creating scaffolds with desired properties, through the use of mixtures and copolymers. The determination of the key parameters of biocompatibility is the basic purpose for testing created materials.Objective. To perform the comparative in vitro study of biocompatibility properties of biopolymer scaffolds produced using polycaprolactone, polylactic acid, their mixtures and copolymers by electrospinning technology.Design and methods. The adhesion properties and cytotoxicity of scaffolds made from polycaprolactone, polylactic acid, copolymer of L- and D-isoforms of lactic acid, their mixtures and co-polymers with the addition of polyglycolic acid were investigated after scaffolds co-cultivation with human mesenchyme stem cells (MSC).Results. The largest number of spread spindle-shaped MSCs was on the surface of polymers containing polyglycolic acid. Besides, the cells on the surface of the copolymer with polyglycolic acid had the morphology closest to the control. The lowest number of living cells was found on the surface of polylactic acid scaffolds, and the highest on the surface of samples from of polycaprolactone and polylactic acid blend.Conclusion. Thus, all tested polymers had good adhesion properties in experiments with human mesenchyme stem cells were possessed by biodegradable polymers with the addition of polyglycolic acid.

Simultaneous Viscum pleurodesis and video-assisted thoracic surgery (VATS) bullectomy in patients with primary spontaneous pneumothorax

Although surgery is the gold standard for treatment of primary spontaneous pneumothorax (PSP), recurrence after surgery remains a concern. This study sought to evaluate the efficacy of simultaneous pleurodesis using Viscum album (VA) extract and video-assisted thoracic surgery (VATS) bullectomy for the treatment of PSP. From March 2016 to June 2020, 175 patients with PSP underwent bullectomy and intraoperative pleurodesis with VA extract at a single institution. All operations were performed through thoracoscopy by one surgeon. Upon completion of bullectomy, a polyglycolic acid sheet was used to cover the stapler lines, and 40 mg of VA extract was instilled over the entire chest wall before chest tube placement. The median operating time was 20 min (interquartile ranges, 15–30) and the median indwelling time of chest drainage was 2 days (interquartile ranges, 2–3). There were no postoperative complications over grade 3. During the median follow-up period of 38 months (interquartile ranges, 15–48), no recurrence of pneumothorax was observed. The results of this study demonstrated that simultaneous Viscum pleurodesis and VATS bullectomy provides a feasible and effective treatment option for preventing postoperative pneumothorax in patients with PSP.

Biodegradable PGA/PBAT Blends for 3D Printing: Material Performance and Periodic Minimal Surface Structures

Biodegradable polymers have been rapidly developed for alleviating excessive consumption of non-degradable plastics. Additive manufacturing is also a green energy-efficiency and environment-protection technique to fabricate complicated structures. Herein, biodegradable polyesters, polyglycolic acid (PGA) and poly (butyleneadipate-co-terephthalate) (PBAT) were blended and developed into feedstock for 3D printing. Under a set of formulations, PGA/PBAT blends exhibited a tailored stiffness-toughness mechanical performance. Then, PGA/PBAT (85/15 in weight ratio) with good thermal stability and mechanical property were extruded into filaments with a uniform wire diameter. Mechanical testing clearly indicated that FDM 3D-printed exhibited comparable tensile, flexural and impact properties with injection-molded samples of PGA/PBAT (85/15). Furthermore, uniform and graded Diamond-Triply Periodic Minimal Surfaces (D-TPMS) structures were designed and successfully manufactured via the fused deposition modeling (FDM) technique. Computer tomography (CT) was employed to confirm the internal three-dimensional structures. The compressive test results showed that PGA/PBAT (85/15) D-surface structures bear better load-carrying capacity than that of neat PGA, giving an advantage of energy absorption. Additionally, typical industrial parts were manufactured with excellent dimension-stability, no-wrapping and fine quality. Collectively, biodegradable PGA/PBAT material with good printability has great potentials in application requiring stiffer structures.

In Vitro Cartilage Regeneration with a Three-Dimensional Polyglycolic Acid (PGA) Implant in a Bovine Cartilage Punch Model

Resorbable polyglycolic acid (PGA) chondrocyte grafts are clinically established for human articular cartilage defects. Long-term implant performance was addressed in a standardized in vitro model. PGA implants (+/− bovine chondrocytes) were placed inside cartilage rings punched out of bovine femoral trochleas (outer Ø 6 mm; inner defect Ø 2 mm) and cultured for 84 days (12 weeks). Cartilage/PGA hybrids were subsequently analyzed by histology (hematoxylin/eosin; safranin O), immunohistochemistry (aggrecan, collagens 1 and 2), protein assays, quantitative real-time polymerase chain reactions, and implant push-out force measurements. Cartilage/PGA hybrids remained vital with intact matrix until 12 weeks, limited loss of proteoglycans from “host” cartilage or cartilage–PGA interface, and progressively diminishing release of proteoglycans into the supernatant. By contrast, the collagen 2 content in cartilage and cartilage–PGA interface remained approximately constant during culture (with only little collagen 1). Both implants (+/− cells) displayed implant colonization and progressively increased aggrecan and collagen 2 mRNA, but significantly decreased push-out forces over time. Cell-loaded PGA showed significantly accelerated cell colonization and significantly extended deposition of aggrecan. Augmented chondrogenic differentiation in PGA and cartilage/PGA-interface for up to 84 days suggests initial cartilage regeneration. Due to the PGA resorbability, however, the model exhibits limitations in assessing the “lateral implant bonding”.

The Use of Autologous Skeletal Muscle Derived Cells as a Sling in the Treatment of Induced Stress Urinary Incontinence, An Experimental Study in Dogs

Introduction:This is an experimental pre-clinical study, testing the applicability of autologous skeletal muscle derived cells as a treatment of SUI in canine modelMethods:10 Mongrel dogs included. Skeletal muscle biopsy was harvested in 4. 1 month later, incontinence was induced in 8 dogs through urethrolysis. Muscle biopsy was incubated and expanded for 8 weeks. Muscle derived cells were collected and covered a Polyglycolic acid (PGA) scaffold immersed in culture medium and coated with matrigel to be used as a sling. Placed suburethral in 8 dogs; 4 had cell- seeded and 4 had scaffold only. Urethral pressure (UP) measurement was done at baseline 2 &6 weeks after sling insertion. The urethra was harvested 4 weeks after sling insertion for histopathology.Results:UP shows increase of maximum urethral pressure during static measurement in all dogs with a scaffold inserted. The increase ranged from 5-40 cmH20 Histopathology shows significant periurethral proliferation of skeletal muscles in 4 dogs with cell-seeded scaffold. This was maximum in dogs # 1& 2. This was not the case in the 4 dogs that had sling only.Conclusion: Use of skeletal muscle –seeded PGA scaffold is a practical technique with preserved integrity of histological differentiation in canine model.

The Importance of pH Adjustment for Preventing Fibrin Glue Dissolution in the Stomach: an in Vitro Study

Background and study aim: Combined use of fibrin glue and polyglycolic acid (PGA) sheets has attracted attention as a preventive measure for complications associated with endoscopic submucosal dissection. However, fibrin glue is a protein that may be dissolved by gastric acid. We evaluated the effect of artificial gastric acid on fibrin clot.Materials and methods: The dissolution time of three layers of fibrin glue with PGA sheets was measured in five groups (pH 1.2, 2.0, 4.0, 5.5, and 6.0 with pepsin). Measurements of three samples per group were made. The mean number of the remaining layers at each measurement point was observed for seven days.Results: The time to complete dissolution of the three layers of fibrin gel in the three samples was 150 minutes at pH 1.2, 5 hours at pH 2.0, 24 hours at pH 4.0, and 2 days and 6 hours at pH 5.5. Conclusion: In order to maintain fibrin glue in the stomach for a long period, there was a need to avoid pepsin activation secondary to acidification of gastric juice. The use of strong antacids is recommended.

Preparation of a Cage-Type Polyglycolic Acid/Collagen Nanofiber Blend with Improved Surface Wettability and Handling Properties for Potential Biomedical Applications

Electrospun biobased polymeric nanofiber blends are widely used as biomaterials for different applications, such as tissue engineering and cell adhesion; however, their surface wettability and handling require further improvements for their practical utilization in the assistance of surgical operations. Therefore, Polyglycolic acid (PGA) and collagen-based nanofibers with three different ratios (40:60, 50:50 and 60:40) were prepared using the electrospinning method, and their surface wettability was improved using ozonation and plasma (nitrogen) treatment. The effect on the wettability and the morphology of pristine and blended PGA and collagen nanofibers was assessed using the WCA test and SEM, respectively. It was observed that PGA/collagen with the ratio 60:40 was the optimal blend, which resulted in nanofibers with easy handling and bead-free morphology that could maintain their structural integrity even after the surface treatments, imparting hydrophilicity on the surface, which can be advantageous for cell adhesion applications. Additionally, a cage-type collector was used during the electrospinning process to provide better handling properties to (PGA/collagen 60:40) blend. The resultant nanofiber mat was then incorporated with activated poly (α,β-malic acid) to improve its surface hydrophilicity. The chemical composition of PGA/collagen 60:40 was assessed using FTIR spectroscopy, supported by Raman spectroscopy.