Effect of collagen denaturation degree on mechanical properties and biological activity of nanofibrous scaffolds.

Further progress in regenerative medicine and bioengineering highly depends on the development of 3D polymeric scaffolds with active biological properties. The most attention is paid to natural extracellular matrix components, primarily collagen. Herein, nonwoven nanofiber materials with various degrees of collagen denaturation and fiber diameters 250-500 nm were produced by electrospinning, stabilized by genipin, and characterized in detail.

A defined road to tracheal reconstruction: laser structuring and cell support for rapid clinic translation.

One of the severe complications occurring because of the patient's intubation is tracheal stenosis. Its incidence has significantly risen because of the COVID-19 pandemic and tends only to increase. Here, we propose an alternative to the donor trachea and synthetic prostheses-the tracheal equivalent.

Implantation of Various Cell-Free Matrixes Does Not Contribute to the Restoration of Hyaline Cartilage within Full-Thickness Focal Defects.

Articular cartilage is a highly organized tissue that has a limited ability to heal. Tissue engineering is actively exploited for joint tissue reconstruction in numerous cases of articular cartilage degeneration associated with trauma, arthrosis, rheumatoid arthritis, and osteoarthritis. However, the optimal scaffolds for cartilage repair are not yet identified.

Experimental Study of the Possibility of Culturing of Mesenchymal Stromal Cell and Induction of Osteogenic Differentiation on Collagen-Based Scaffolds of Various Modifications.

We analyzed the suitability of various collagen-based scaffolds for culturing and osteogenic differentiation of mesenchymal stromal cells (MSC). Decellularized and lyophilized swine intestinal submucosa (SIS) and porous collagen sponge made from reconstructed bovine derma (PCS) were the most effective in promoting MSC adhesion, survival, and growth. MSC from rat and mouse bone marrow and rat adipose tissue successfully adhered to the scaffold surface and penetrated into its deep layers.

Multiparametric Optical Bioimaging Reveals the Fate of Epoxy Crosslinked Biomeshes in the Mouse Subcutaneous Implantation Model.

Biomeshes based on decellularized bovine pericardium (DBP) are widely used in reconstructive surgery due to their wide availability and the attractive biomechanical properties. However, their efficacy in clinical applications is often affected by the uncontrolled immunogenicity and proteolytic degradation. To address this issue, we present here multiparametric imaging analysis of epoxy crosslinked DBPs to reveal their fate after implantation.

Mammalian Pericardium-Based Bioprosthetic Materials in Xenotransplantation and Tissue Engineering.

Bioprosthetic materials based on mammalian pericardium tissue are the gold standard in reconstructive surgery. Their application range covers repair of rectovaginal septum defects, abdominoplastics, urethroplasty, duraplastics, maxillofacial, ophthalmic, thoracic and cardiovascular reconstruction, etc. However, a number of factors contribute to the success of their integration into the host tissue including structural organization, mechanical strength, biocompatibility, immunogenicity, surface chemistry, and biodegradability.

Chemical cross-linking of xenopericardial biomeshes: A bottom-up study of structural and functional correlations.

Decellularized bovine pericardium (DBP)-based biomeshes are the gold standard in reconstructive surgery. In order to prolong their stability after the transplantation, various chemical cross-linking strategies are employed. However, structural and functional properties of the biomeshes differ in dependence on the cross-linker used.

2D/3D buccal epithelial cell self-assembling as a tool for cell phenotype maintenance and fabrication of multilayered epithelial linings in vitro.

Maintaining the epithelial status of cells in vitro and fabrication of a multilayered epithelial lining is one of the key problems in the therapy using cell technologies. When cultured in a monolayer, epithelial cells change their phenotype from epithelial to epithelial-mesenchymal or mesenchymal that makes it difficult to obtain a sufficient number of cells in a 2D culture and to use them in tissue engineering. Here, using buccal epithelial cells from the oral mucosa, we developed a novel approach to recover and maintain the stable cell phenotype and form a multilayered epithelial lining in vitro via the 2D/3D cell self-assembling.

Control on rheological behavior of collagen 1 dispersions for efficient electrospinning.

For efficient manufacturing of fibrous collagen-based materials by electrospinning, the search on optimal rheological parameters is of the great importance. Rheological characteristics and denaturation of collagen in aqueous dispersions were studied as a function of shear rate and acetic acid concentration in the range of 3-9% w/w at temperature from 20 to 40°C. It was shown that an increase in temperature, acetic acid concentration of the collagen dispersion leads to a significant decrease in its viscosity.

Reinforced Hybrid Collagen Sponges for Tissue Engineering.

We created an anisotropic material based on collagen sponge and reactive polylactide structured by laser photopolymerization. The combination of collagen with reactive polylactide improves the resistance of the formed matrices to biodegradation in comparison with collagen sponge, while the existence of sites with different mechanical characteristics and cell affinity on the matrix provides directed cell growth during their culturing. It was shown that reinforcement of the collagen sponges 7-fold increased the mean Young's modulus for the hybrid matrix without affecting its cytotoxicity.

[Morphology of collagen matrices for tissue engineering (biocompatibility, biodegradation, tissue response)].

Objective: to perform a comparative morphological study of biocompatibility, biodegradation, and tissue response to implantation of collagen matrices (scaffolds) for tissue engineering in urology and other areas of medicine.

Material And Methods: Nine matrix types, such as porous materials reconstructed from collagen solution; a collagen sponge-vicryl mesh composite; decellularized and freeze-dried bovine, equine, and fish dermis; small intestinal submucosa, decellularized bovine dura mater; and decellularized human femoral artery, were implanted subcutaneously in 225 rats. The tissues at the implantation site were investigated for a period of 5 to 90 days.

[PLGA mesh-collagen hybrid scaffold and tissue-engineered product in substitution urethroplasty: experimental validation].

Urethral strictures are a pressing issue in modern medicine. Substitution urethroplasty is considered one of the most effective treatment methods. However, despite the surgery showing good results, many problems remain unresolved, one being substitute material deficiency in extensive or recurrent strictures, as well as in cases requiring multistage surgeries, including those used to treat hypospadias.

[TISSUE-ENGINEERED SUBSTITUTION URETHROPLASTY BASED ON DECELLULARIZED VASCULAR MATRIX AND AUTOLOGOUS CELLS OF THE BUCCAL MUCOSA: THE FIRST EXPERIENCE].

Urethral strictures and anomalies remain a challenging urological problem. Reconstructive plastic surgery has been shown to be the most effective way to treat them. There are two main types of urethroplasty: anastomosis (anastomotic urethroplasty) and expansion of the urethral lumen using of flaps and grafts (substitution urethroplasty).

Dinitrosyl iron complexes with glutathione incorporated into a collagen matrix as a base for the design of drugs accelerating skin wound healing.

Composites of a collagen matrix and dinitrosyl iron complexes with glutathione (DNIC-GS) (in a dose of 4.0 μmoles per item) in the form of spongy sheets (DNIC-Col) were prepared and then topically applied in rat excisional full-thickness skin wound model. The effects of DNIC-Col were studied in comparison with spontaneously healing wounds (SpWH) and wounds treated with collagen sponges (Col) without DNIC-GS.

[Experimental validation of the developing a matrix based on decellularized vascular wall for subsequent substitution urethroplasty].

Urethral strictures are urgent urological problem. Anastomotic and substitution urethroplasty are the most effective treatments. For substitution urethroplasty, buccal mucosa is most often used.

Stimulation of regeneration of hyaline cartilage in experimental osteochondral injury.

A model of osteochondral intra-articular defect in rats is presented. During spontaneous healing, the stage of formation of granulation tissue is followed by its replacement with bone and fibrous tissue. Chondroinductive properties of collagen 1 sponge used for defect filling manifested in the formation of fibrous cartilage with fields of hyaline cartilage.

[Investigation of dysbiosis developing during "dry" immersion and methods of correction].

Dysbiotic shifts in intestinal and integumentary microflora were studied in 10 test-subjectes during 7-day "dry" immersion. Essentially every test-subject reduced significantly fecal lactoflora and developed dysbiotic shifts in the microbial landscape of various types of integument. Pharyngeal microflora was analyzed in 22 normal volunteers for 7-day "dry" immersion.

The use of bioactive wound dressing, stimulating epithelial regeneration of IIIa-degree burn wounds.

Clinical and morphological comparison of wound healing after transplantation of living cultured allofibroblast on days 1-2 after the injury, collagen-1-based dressing with PDGF-BB, and traditional dressing with levomecol ointment showed that bioactive dressing accelerated wound epithelialization (5-7 days vs. 20-22 days with gauze dressing); the incidence of suppurative complications decreased, no crust formed, and epithelialization was not associated with the formation of a hypertrophic cicatrix. Biological dressing based on living cultured allofibroblasts and collagen-1 with PDGF-BB exhibited equal stimulatory effects on burn wound healing.

[Effect of short-term application of a lactate-containing probiotic on the pharyngeal microflora in healthy subjects].

Daily dynamics of pharyngeal microflora was evaluated in the absence of preventive treatment and using a local lactate-producing probiotic preparation during 24 hour-long simulated microgravity. The study showed that the short-term application of the local lactate-producing probiotic (four times daily) significantly reduced titers of opportunistic pathogenic microflora and increased the amount of symbionts in the pharynx.

[Treatment of IIIa grade burns with the biologic band].

The biologic band is created on the base of type I collagen and platelet derived growth factor. It was applied for extensive burns of IIIa grade at 1-2nd day after a trauma, which led to epidermis reconstruction at 5-7th day. Authors assume that the effect of the band is determined by the time of its use--1-2nd day, when stimulating exudation qualities combine with healing properties of the bandage.

[Experimental grounds for administration of probiotic drugs in conditions of hydroweightlessness].

We studied pharyngeal microflora in 22 healthy volunteers after 7-day dry immersion. For prophylactic pharyngeal dysbiosis, we used two probiotic drugs: oral -- "lactobacterin dry" and local --"lactobacterin immobilized on collagen". Administration of oral probiotic was accompanied with growth of pharyngeal opportunistic microflora preventing translocation of intestinal microflora.

[Development and use of periodontal dressing of collagen and Lactobacillus casei 37 cell suspension in combined treatment of periodontal disease of inflammatory origin (a microbiological study)].

Periodontal dressing consisting of collagen and Lactobacillus casei 37 cell suspension (cell concentration 108 cells/ml) was created and used in combined treatment of patients with chronic generalized parodontitis. Efficacy of the developed isolation was explained by a considerable decrease of the number and frequency of isolation of aggressive microbial representatives (pigment synthesizing Bacteroids, Actinomyces and Str. intermedius) in periodontal pockets and also Fungus (Candida albicans).

[Application hemostatic drug in capillary-parenchymatous bleeding].

Specific activity of a new hemostatic drug thrombocol was studied in experiments. Laboratory rabbits were used for management of experimental capillary-parenchymatous hemorrhage. The action of thrombocol was compared with hemostatic effect of other drugs: carbocol, combutek-2, super-4 (USA), collastipt (Germany), collagen sponge (Germany).

[Method of protecting of sutures in the stomach and intestines].

The authors have developed and described the method for intraoperative prophylaxis of complications caused by incompetence of the sutures on the stomach and bowels. It consists in closure of the sutures along the line of contiguity by two-layers of compact-porous collagenous explants, which possess antibacterial properties, the period of resorption in abdominal cavity being 15-20 days. The characteristics of the explants are presented and their advantages compared to commonly used methods covering by pellicle or glue film peritonization by sero-muscular sutures.