[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). Currently the ideal material for substitution urethroplasty does not exist. Tissue engineering of the urethra seems to be one of the most promising approaches to address this problem. Various tissues-engineering techniques were proposed for substitution urethroplasty. In this study, tissue-engineering design was based on the decellularized cadaveric arterial wall. The study results demonstrated the feasibility of creating stable tissue-engineered structures with autologous cultured epithelial cells of the buccal mucosa and decellularized matrix from human cadaveric arterial wall (DMCAW). There was a complete engraftment of tissue-engineering design based on DMCAW and buccal mucosa cells, used for substitution urethroplasty in a patient with the bulbar urethral stricture. Postoperatively (within 4 months after surgery) no complications and/or adverse events were observed. However, in the late postoperative period (12 months) there was recurrence of urethral stricture in the middle of the tissue-engineering design and the native urethra that warranted another surgery. Tissue-engineering design based on DMCAW and autologous buccal mucosa is safe as a material for substitution urethroplasty. Further research is required to ascertain the effectiveness of the method.

[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. There are the following difficulties associated with the substitution urethroplasty: complications in the donor area, the lack of tissue for substitution, an additional incision, and increased timing of surgery due to the need to obtain a flap or graft. Tissue engineering can be useful in solving the above problems. Tissue engineering involves the use a matrix without cells and matrix with one or more types of cells (tissue-engineering designs). In our study we have evaluated the ability to create a matrix for the substitution urethroplasty in animal experiments. The decellularized cadaveric arterial wall was used as a matrix. Decellularization was performed using enzymatic method. At the first stage, we transplanted matrix fragments in interscapular region in rats. An extremely weak bioactivity dof decellularized matrix of cadaveric arterial wall (DMCAW) due to the low immunogenicity of the material was revealed. Thus resorption of DMCAW was quite slow (60-90 days). At the second stage, in an experiment on rabbits, substitution urethroplasty using tubular DMCAW was successfully performed. Intraoperative urethral defect up to 1.8 cm was created, which was replaced by a tubular DMCAW. The use of this type of matrix has showed good structural and functional results: urethral strictures did not arise, the rejection of the matrix was not observed. A slow degradation of the matrix and progressive epithelialization of onnective tissue capsule were revealed. Decellularized matrix based on cadaveric arterial wall can be considered as a material for substitution urethroplasty.

[Methods of tissue engineering of bone tissue in maxillofacial surgery].

For the last decade many experimental and clinical data about the study and application of regenerative medicine methods in the maxillofacial surgery were accumulated. For better bone regeneration mesenchymal stem cells are often used. Considering the general wariness of researchers in some aspects of cell therapy, methods of study of mesenchymal stem cells and the technologies of its clinical application are constantly being upgraded. This review will consider methods of tissue engineering used to regenerate bone tissue defects in maxillofacial surgery.

Overexpression in Escherichia coli and purification of human fibroblast growth factor (FGF-2).

Basic fibroblast growth factor (FGF-2) is a member of a large family of structurally related proteins that affect the growth, differentiation, migration, and survival of many cell types. The human FGF-2 gene (encoding residues 1-155) was synthesized by PCR from 20 oligonucleotides and cloned into plasmid pET-32a. A high expression level (1 g/liter) of a fused protein thioredoxin/FGF-2 was achieved in Escherichia coli strain BL21(DE3). The fusion protein was purified from the soluble fraction of cytoplasmic proteins on a Ni-NTA agarose column. After cleavage of the thioredoxin/FGF-2 fusion with recombinant human enteropeptidase light chain, the target protein FGF-2 was purified on a heparin-Sepharose column. The yield of FGF-2 without N- and C-terminal tags and with high activity was 100 mg per liter of cell culture. Mutations C78S and C96S in the amino acid sequence of the protein decreased FGF-2 dimer formation without affecting its solubility and biological activity.