Modeling of Biological Activity of PEO-Coated Titanium Implants with Conjugates of Cyclic RGD Peptide with Amino Acid Bisphosphonates

Titanium is considered to be the most essential metal in the field of implantology. The main factors determining metal biocompatibility, among others, include the morphology and chemical composition of the titanium surface. Therefore, the aim of this work was to develop approaches to control the biological activity of the titanium surface by creating coatings that combine both an inorganic phase with a given morphology and organic molecules containing an integrin-selective peptide that regulate cell adhesion and proliferation. As such, we synthesized new c(RGDfC) derivatives of amino acid bisphosphonates (four examples) with different bisphosphonate anchors and maleimide linkers. These molecules were deposited on a highly developed porous surface obtained via the plasma electrolytic oxidation (PEO) of coarse-grained and nanostructured titanium. In vitro studies demonstrated the increase in the viability degree of mesenchymal stem cells and fibroblasts on the surface of coarse-grained or nanostructured titanium modified with PEO and a c(RGDfC) derivative of ε-aminocaproic acid bisphophonate with an SMCC linker. As a result, the use of conjugates of amino acid bisphosphonates with a cyclic RGD peptide for the modification of PEO-coated titanium opens the ways for the effective control of the biological activity of the metal implant surface.

Interaction Of Immune Response Mediator Genes In A Predisposition To Juvenile Idiopathic Arthritis

Background/objective — The goal of our study was to investigate the role of interaction between the polymorphic loci of immune response mediator genes (TNFA rs1800629, LTA rs909253, IL1B rs16944, IL2-IL21 rs6822844, IL2RA rs2104286, IL6 rs1800795, IL10 rs1800872, MIF rs755622, CTLA4 rs3087243, NFKB1 rs28362491, PTPN22 rs2476601, and PADI4 rs2240336) in the formation of a genetic predisposition to juvenile idiopathic arthritis (JIA). Material and Methods — The study involved 330 JIA patients and 342 volunteers from the Republic of Bashkortostan. Genotyping was conducted via the real-time polymerase chain reaction. The gene-gene interactions were studied using the multifactor dimensionality reduction algorithm. Results — In general analysis, the best model of gene-gene interaction in JIA was a combination of IL1B rs16944 – IL10 rs1800872 – NFKB1 rs28362491 – PADI4 rs2240336 polymorphic loci. However, after gender-based stratification the best results were obtained when examining the combinations of IL6 rs1800795 – PADI4 rs2240336 loci in girls and of IL10 rs1800872 – IL6 rs1800795 – IL2RA rs2104286 loci in boys. Within all of these models, the genotype combinations associated with both augmented and reduced JIA risks were identified (taking into account gender-specific differences). Conclusion — The results of our study implied that an important role in the formation of a predisposition to JIA is played by gene-gene interactions of IL1B rs16944, IL2RA rs2104286, IL6 rs1800795, IL10 rs1800872, NFKB1 rs28362491, and PADI4 rs2240336 polymorphic loci (taking into account gender-specific differences).

[Complex association analysis of antioxidant genes polymorphic DNA-markers with age in the ethnic group of Abkhazians.]

For the first time in the ethnic group of Abkhazians, the association analysis of polymorphic DNA-markers of the antioxidant genes CAT (rs1001179), MSRA (rs10098474), GPX1 (rs1050450), GSR (rs1002149), GSTP1 (rs1695), SOD1 (rs2070424), SOD2 (rs4880), PON1 (rs662), PON2 (rs7493) with age was performed. Using ROC-analysis and logistic regression, it was found that the spectrum of alleles and genotypes frequencies of PON1 and GSTP1 genes polymorphic markers change throughout the studied age period (21-107 years old); the distribution of allele and genotype frequencies of CAT and SOD2 genes polymorphic markers changes within the age of 60 years. Multilocus genetic markers of longevity were determined by the Monte Carlo Markov chain method. Among persons in the age range 60-107 years, the frequency of observation of the patterns GSTP1*G/G+PON1*G (OR=6,59, PFDR=0,018) and GSTP1*G/G+SOD1*A (OR=3,4, PFDR=0,041) is statistically significantly increased; the GSTP1*A allele in various combinations with the PON1*A, PON2*C and CAT*C alleles are less common (OR=0,3, PFDR<0,05).

Biocompatible Organic Coatings Based on Bisphosphonic Acid RGD-Derivatives for PEO-Modified Titanium Implants

Currently, significant attention is attracted to the problem of the development of the specific architecture and composition of the surface layer in order to control the biocompatibility of implants made of titanium and its alloys. The titanium surface properties can be tuned both by creating an inorganic sublayer with the desired morphology and by organic top coating contributing to bioactivity. In this work, we developed a composite biologically active coatings based on hybrid molecules obtained by chemical cross-linking of amino acid bisphosphonates with a linear tripeptide RGD, in combination with inorganic porous sublayer created on titanium by plasma electrolytic oxidation (PEO). After the addition of organic molecules, the PEO coated surface gets nobler, but corrosion currents increase. In vitro studies on proliferation and viability of fibroblasts, mesenchymal stem cells and osteoblast-like cells showed the significant dependence of the molecule bioactivity on the structure of bisphosphonate anchor and the linker. Several RGD-modified bisphosphonates of β-alanine, γ-aminobutyric and ε-aminocaproic acids with BMPS or SMCC linkers can be recommended as promising candidates for further in vivo research.

The role of the immune response mediator genes polymorphism in the predisposition to juvenile idiopathic arthritis

Objective ― The aim of the work was to study the contribution of the immune response mediator genes polymorphism (TNFA rs1800629, LTA rs909253, IL1B rs16944, IL2-IL21 rs6822844, IL2RA rs2104286, IL6 rs1800795, IL10 rs1800872, MIF rs755622, CTLA4 rs3087243, NFKB1 rs28362491, PTPN22 rs2476601, PADI4 rs2240336) to the formation of the predisposition to juvenile idiopathic arthritis (JIA) and its clinical variants. Material and Methods ― The JIA group included 330 patients and the control group – 342 volunteers without autoimmune diseases from the Republic of Bashkortostan, Russia. Genotyping was conducted by the real-time polymerase chain reaction. Results ― Taking into account the differences by sex, it was established, that the alleles/genotypes of the TNFA rs1800629, LTA rs909253, IL2-IL21 rs6822844, PTPN22 rs2476601 polymorphic loci and the TNFA rs1800629*G – LTA rs909253*G haplotype are associated with the development of JIA as a whole (p<0.05); alleles/genotypes of the LTA rs909253, IL1B rs16944, IL2-IL21 rs6822844, IL2RA rs2104286, IL6 rs1800795, IL10 rs1800872, MIF rs755622, CTLA4 rs3087243, NFKB1 rs28362491, PTPN22 rs2476601 polymorphic loci and the TNFA rs1800629*G – LTA rs909253*G haplotype – with some of JIA clinical variants (p<0.05). Conclusion ― In this work, the relationship of the alleles, genotypes and haplotypes of a number of the immune response mediator genes polymorphic loci with the risk of the development of JIA and its clinical variants was established. Specific associations were observed for girls and boys, which indicates the existence of sexual dimorphism in the JIA pathogenesis.

[Experimental morphological rationale for the use of cultures of multipotent mesenchymal stem cells in combination with biomaterials in the reconstruction of the pelvic floor]

To date, descension of the pelvic floor is a fairly common gynecological pathology that requires surgical treatment. The development of cellular technologies suggests that the use of multipotent mesenchymal stem cells (MMSC) in the treatment of this pathology can stimulate the regeneration of damaged tissue and contribute to the reconstruction of the structures of the pelvic floor.

OBJECTIVE

to evaluate the effectiveness of using MMSC in combination with biological and synthetic materials in vitro and in vivo with descension of the pelvic floor.

MATERIALS AND METHODS

Sprague Dawley rats 10 weeks old weighing 200 grams were used in the experiment. Under sterile conditions, mechanical damage to the posterior wall of the vagina was carried out, with the restoration of which vicryl 3-0 was used. On the 2nd and 4th day, the wound was cut off in a volume of 1.5 ml with xenograft, allograft and multipotent mesenchymal stem cells (MMSC) (5 thousand cells) obtained from the adipose tissue of rats. In the control group was not used biological material. At the second stage of the experiment, the compatibility of the mesh prosthesis with MMSC and allograft in vitro was evaluated.

RESULTS AND DISCUSSION

xenograft does not lead to full tissue regeneration, but contributes to rapid epithelialization and reduces the degree of inflammatory reaction in the wound during the regeneration of connective tissue. The use of allograft leads to quick and complete epithelialization of the wound and the formation of a structurally complete connective tissue lamina of the vaginal mucosa. The introduction of MMSC resulted in complete epithelialization of the wound and the formation of a structurally complete connective tissue plate of the mucosa and submucosa, but with a slightly smaller number of blood vessels in them than with the use of a biomaterial. At the second stage of the experiment, weak cell adhesion to the polypropylene substrate of the tablet was observed during cell culture in the presence of only a fragment of the mesh prosthesis. After MMSC cultivation in the presence of a mesh prosthesis fragment and an allograft, a relatively uniform distribution of cells around the mesh prosthesis loops was observed.

CONCLUSIONS

it was determined that the use of MMSC and allograft has a positive effect on the process of vaginal tissue regeneration in rats. When combining these materials with mesh prostheses, it was found that MMSCs are not fixed directly to the synthetic material, but when the allograft is added, they concentrate and presumably have the maximum anti-inflammatory effect and promote tissue regeneration at the site of the mesh prosthesis. Thus, the use of autologous MMSC cells in combination with allograft and mesh polymeric materials for pelvic floor reconstruction can significantly improve the results of reconstructive operations.

[Association of cytokines genes (ILL, IL1RN, TNF, LTA, IL6, IL8, IL0) polymorphic markers with chronic obstructive pulmonary disease]

The purpose of this study was to investigate the possible roles of the cytokines genes in the development of chronic obstructive pulmonary disease (COPD). Polymorphisms in the genes encoding IL1B, IL1RN, TNFA, LTA, IL6, IL8 H IL10 were investigated in COPD patients (N = 319) and healthy individuals (N = 403) living in Ufa, the Republic of Bashkortostan. We observed that IL1RN*2/IL1RN*2 genotype of ILRN gene was associated with susceptibility for COPD (9.8% vs. 4.67%; chi(2)= 5.45, df= 1, P = 0.02; OR = 2.21). Analysis of the LTA gene polymorphic locus A252G showed that in patients with COPD, the frequency of the GG genotype was significantly higher than that in the control group (7.84% vs. 3.72%; chi(2) = 5.00, df= 1, P = 0.025). The increase of this genotype was significant in case of stage IV of COPD (11.18% vs. 4.79%; chi(2) = 3.075, df= 1, P = 0.07). Frequency of genotype combination TNFA-308 G/G and LTA252 A/A significantly decreased in COPD group (38.55% vs. 46.93% in control group; chi(2) = 8.82, df= 1, P = 0.0039). The frequency of GG genotype of the IL6 gene was higher in the patients with stage IV of COPD (43.75% vs. 31.54%, chi(2) = 4.14, P = 0.041). Our results indicate that the genotype frequency of the T(-511)C, T3953C of IL1B, G(-308)A of TNFA, G(-1 74)C of IL6, A(-251)C of IL8 and C(-627)A of ILl0 genes polymorphisms was similar in COPD and healthy control groups.