Formation Of New Bone Tissue Research Articles

Comparative histomorphological assessment of the osteoinductive capacity of a nanofibrillated cellulose-based composite and autologous blood clot.

The present study aimed to evaluate and compare the effect of nanofibrillated cellulose (NFC)-based composite with dicalcium phosphate dihydrate and an autologous blood clot (ABC) on the formation of new bone tissue in vivo by histological and histomorphometric assessment. A total of 72 rats with created femoral defects (2 mm) were used. The rats were divided into three groups: (1) with filling of the defect with an ABC, (2) NFC-1-with filling of both the cortical plate and intramedullary space in the defect area, and (3) NFC-2-with filling of only the intramedullary space in the defect area. Histological and histomorphometric analysis was performed to assess the healing of the bone defect after 14, 30 and 60 days. Complete closure of the cortical plate defect was detected in the NFC-2 group on Day 30 (p < 0.0001). Moreover, in both NFC groups on the 30th and 60th days, ongoing osteogenesis was observed, characterized by a large volume of newly formed circular pattern bone tissue in the intramedullary space. This study demonstrated that the NFC-based composite, which is located below the level of the cortical plate, tamponing only the intramedullary space (NFC-2), improves bone tissue repair at the site of a bone defect of the cortical plate and has the potential of prolonged osteoinductivity. Not applicable.

Design and Testing of an Intramedullary Nail Implant Enhanced with Active Feedback and Wireless Connectivity for Precise Limb Lengthening

This comprehensive study presents a pioneering approach to limb lengthening, leveraging the advancements in wireless technology to enhance orthopedic healthcare. Historically, limb lengthening has been a response to discrepancies caused by fractures, diseases, or congenital defects, utilizing the body’s innate ability to regenerate bone and surrounding tissues. Traditionally, this involved external or internal fixation devices, such as the Ilizarov and Taylor Spatial frames or the Precice nail and Fitbone. The focal point of this research is the development and testing of a wireless intramedullary nail implant prototype, controlled remotely via a mobile application. This implant comprises a microcontroller, Bluetooth Low Energy module, a brushed DC motor controlled through an H-bridge, and a force sensor, all powered by medical-grade batteries. The integration of wireless technology facilitates patient autonomy in managing limb lengthening, reducing the need for frequent clinical visits. The methodology involves a detailed block diagram for our proposed work, outlining the process from treatment planning to the initiation of limb lengthening via the mobile application. Osteogenesis, the formation of new bone tissue, plays a crucial role in this procedure, which includes pre-surgery assessment, osteotomy, latency, distraction, consolidation, and removal phases. Key challenges addressed include custom battery design for efficient operation, size constraints, and overcoming signal interference due to the Faraday cage effect. Attenuation testing, simulating human tissue interaction, validates the implant’s connectivity. In conclusion, this research marks a significant stride in orthopedic care, demonstrating the feasibility of a wireless implant for limb lengthening. It highlights the potential benefits of reduced clinical visits, cost efficiency, and patient convenience. Despite limitations such as battery requirements and signal interference, this study opens avenues for future enhancements in patient-centered orthopedic treatments, signaling a transformative shift in managing limb length discrepancies.

Application of Bioactive Materials for Osteogenic Function in Bone Tissue Engineering.

Bone tissue defects present a major challenge in orthopedic surgery. Bone tissue engineering using multiple versatile bioactive materials is a potential strategy for bone-defect repair and regeneration. Due to their unique physicochemical and mechanical properties, biofunctional materials can enhance cellular adhesion, proliferation, and osteogenic differentiation, thereby supporting and stimulating the formation of new bone tissue. 3D bioprinting and physical stimuli-responsive strategies have been employed in various studies on bone regeneration for the fabrication of desired multifunctional biomaterials with integrated bone tissue repair and regeneration properties. In this review, biomaterials applied to bone tissue engineering, emerging 3D bioprinting techniques, and physical stimuli-responsive strategies for the rational manufacturing of novel biomaterials with bone therapeutic and regenerative functions are summarized. Furthermore, the impact of biomaterials on the osteogenic differentiation of stem cells and the potential pathways associated with biomaterial-induced osteogenesis are discussed.

Magnetic field application in bone tissue regeneration: issue current status and prospects for method development

Relevance. Magnets have long been used to treat various diseases, especially in inflammatory processes. According to existing historical data, magnetotherapy was already used in ancient times by the Chinese, Egyptians and Greeks. Different magnetic field strengths affect cells in different ways, with medium-strength magnetic fields being the most widely used. The review presents a brief history and current state of the issue of using a magnetic field in bone tissue regeneration. Modern knowledge about the mechanisms of physiological and reparative regeneration, restoration of bone tissue is clarified, and modern areas of bone tissue engineering are considered, taking into account the characteristics of microcirculation and the effect of a magnetic field on the physiology of bone tissue and reparative regeneration. One of the key findings of the review is that the magnetic field improves bone tissue repair by influencing the metabolic behavior of cells. Studies show that magnetotherapy promotes the activation of cellular processes, accelerates the formation of new bone tissue and improves its quality. It is also noted that the magnetic field has a positive effect on microcirculation, improving the blood supply to tissues and facilitating a better supply of nutrients to the site of injury. This contributes to faster wound healing and early rehabilitation of patients. Conclusion. Magnetotherapy is one of the effective physical and rehabilitation methods of treatment that will become increasingly important in modern medicine. However, further research is needed to better understand the mechanisms of action of a magnetic field on bone tissue and to determine the optimal parameters for its application.

In vivo study on osteogenic efficiency of nHA/ gel porous scaffold with nacre water-soluble matrix

Background/purposeNano-hydroxyapatite (nHA)/ gel porous scaffolds loaded with WSM carriers are promising bone replacement materials that can improve osseointegration ability. This investigation aimed to evaluate the osteoinductive activity by implanting the composition of nano-hydroxyapatite (nHA)/ Gel porous scaffolds as a carrier of WSM via an animal model. Materials and methods: WSM was extracted and nHA was added to the matrix to construct porous composite scaffolds. The dose-effect curve of WSM concentration and alkaline phosphatase (ALP) activity was made by culturing rat osteoblasts and examining the absorbance. Three different materials were implanted into critical size defects (CSD) in the skulls of rats, which were further divided into four groups: WSM nHA /Gel group, n-WSM nHA /Gel group, HA powder group, and control group. Results: WSM (150 μg/mL-250μg/mL) effectively improved the activity of ALP in rat osteoblasts. All rats in each group had normal healing. WSM-loaded nHA /Gel group showed better performance on newly-formed bone tissue of rat skull and back at 4th week and 8th week, respectively. At the 4th week, the network of woven bone formed in the WSM-loaded nHA/Gel scaffold material. At 8th week, the reticular trabecular bone in the WSM-loaded scaffold material became dense lamellar bone, and the defect was mature lamellar bone. In the subcutaneous implantation experiment, WSM-loaded nHA/Gel scaffold material showed a better performance of heterotopic ossification than the pure nHA/Gel scaffold material. Conclusion: WSM promotes osteoblast differentiation and bone mineralization. The results confirm that the nHA/ Gel Porous Scaffold with Nacre Water-Soluble Matrix has a significant bone promoting effect and can be used as a choice for tissue engineering to repair bone defects.

Advancements in incorporating metal ions onto the surface of biomedical titanium and its alloys via micro-arc oxidation: a research review.

The incorporation of biologically active metallic elements into nano/micron-scale coatings through micro-arc oxidation (MAO) shows significant potential in enhancing the biological characteristics and functionality of titanium-based materials. By introducing diverse metal ions onto titanium implant surfaces, not only can their antibacterial, anti-inflammatory and corrosion resistance properties be heightened, but it also promotes vascular growth and facilitates the formation of new bone tissue. This review provides a thorough examination of recent advancements in this field, covering the characteristics of commonly used metal ions and their associated preparation parameters. It also highlights the diverse applications of specific metal ions in enhancing osteogenesis, angiogenesis, antibacterial efficacy, anti-inflammatory and corrosion resistance properties of titanium implants. Furthermore, the review discusses challenges faced and future prospects in this promising area of research. In conclusion, the synergistic approach of micro-arc oxidation and metal ion doping demonstrates substantial promise in advancing the effectiveness of biomedical titanium and its alloys, promising improved outcomes in medical implant applications.

РОЛЬ КОЛЛАГЕНА И ГИДРОКСИАПАТИТА В СОСТАВЕ КОМПОЗИЦИОННЫХ КОСТНОПЛАСТИЧЕСКИХ МАТЕРИАЛОВ, ИСПОЛЬЗУЕМЫХ В ЧЕЛЮСТНО-ЛИЦЕВОЙ ХИРУРГИИ (обзор литературы)

Abstract. Introduction. Bone tissue reconstruction is one of the most challenging problems of maxillofacial surgery. This paper provides a review of studies related to the use of hydroxyapatite- and collagen-based osteoplastic materials for jawbone defects. Aim of our study is the review of the latest information on how essential collagen and hydroxyapatite as part of osteoplastic composites used in maxillofacial surgery. Materials and Methods. The published topical studies are reviewed, dealing with the study of collagen and hydroxyapatite as part of osteoplastic composites. Results and Discussion. Collagen implants promote fibroblast proliferation, vascularization of nearby tissues and induce the formation of new bone tissue with its subsequent restructuring. Collagen was also used as a rapidly biodegrading material in form of a gel for the restoration of bone defects. Conclusions. Currently, considering the positive qualities of collagen and hydroxyapatite, we see their widespread use as part of composite bone plastic materials as promising.

A Synergic Strategy: Adipose-Derived Stem Cell Spheroids Seeded on 3D-Printed PLA/CHA Scaffolds Implanted in a Bone Critical-Size Defect Model.

Bone critical-size defects and non-union fractures have no intrinsic capacity for self-healing. In this context, the emergence of bone engineering has allowed the development of functional alternatives. The aim of this study was to evaluate the capacity of ASC spheroids in bone regeneration using a synergic strategy with 3D-printed scaffolds made from poly (lactic acid) (PLA) and nanostructured hydroxyapatite doped with carbonate ions (CHA) in a rat model of cranial critical-size defect. In summary, a set of results suggests that ASC spheroidal constructs promoted bone regeneration. In vitro results showed that ASC spheroids were able to spread and interact with the 3D-printed scaffold, synthesizing crucial growth factors and cytokines for bone regeneration, such as VEGF. Histological results after 3 and 6 months of implantation showed the formation of new bone tissue in the PLA/CHA scaffolds that were seeded with ASC spheroids. In conclusion, the presence of ASC spheroids in the PLA/CHA 3D-printed scaffolds seems to successfully promote bone formation, which can be crucial for a significant clinical improvement in critical bone defect regeneration.

Effect of Platelet-rich Plasma Combined with Marburg Bone Bank-prepared Bone Graft in Rabbit Bone Defect Model

Background: An effective technique for inducing bone formation without using an autograft has yet to be established. Platelet-rich plasma (PRP), which can be obtained easily from whole blood, contains substantial growth factors (GFs) that can facilitate bone regeneration and growth. Objectives: This study aimed to evaluate the effect of PRP combined with a Marburg bone bank-prepared bone graft in a rabbit bone defect model. Methods: This study utilized 32 rabbits (n = 16 in each group). Bone defects were intentionally made in the femur, and the bone allograft used was the human femoral head prepared according to the Marburg bone bank. Rabbits were divided into Marburg bone graft (MBG) and MBG+PRP groups. Histopathological and histomorphometric analyses were conducted 14 and 30 days post-surgery. Results: A greater new bone formation was detected in both groups on the 14th and 30th days (P = 0.001). Furthermore, more pronounced angiogenesis was found in the MBG+PRP group than in the MBG group (P = 0.001). Conclusions: The MBG-PRP complex significantly enhanced bone tissue repair in bone defects. The inclusion of PRP was found to promote angiogenesis and stimulate the formation of new bone tissue, further supporting the beneficial effects of this combination in the healing process.

A Model of Type II Collagen-Induced Spondylitis and Arthritis in F1 Hybrid Male Mice.

In this study, we tested a new model of ankylosing spondylitis in order to determine its histological and radiological features needed to investigate peripheral arthritis, spondylitis, and formation of the new bone tissues. F1 hybrid male mice (BALB/c×DBA/1), a progeny of spondylitis-susceptible BALB/c male mice and rheumatoid arthritis-susceptible DBA/1 female mice, were immunized intraperitoneally with bovine type II collagen (CII) mixed with adjuvant dimethyldioctadecylammonium bromide. Radiological and histological studies were performed at the peak of swelling, redness, and stiffness. The incidence of peripheral arthritis and spondylitis induced by CII in F1 hybrid mice were 66 and 62%, respectively. X-ray examination revealed bone erosion and spondylitis in the peripheral joints, as well as the formation of new bone tissues in the coccygeal vertebrae and between LIII and LIV vertebrae. The histological study showed lymphocyte and plasma cell infiltration, capillary dilation, congestion, and endochondral ossification of the lumbar vertebrae. This novel model of CII-induced spondylitis in F1 hybrid mice provoked axial and peripheral arthritides inducing chronic inflammation. In this model, the formation of new bone tissue in the stiff spine is characterized by endochondral ossification. The advanced model is an additional and valuable tool for investigation of the autoimmune reactions in spondylitis.

Regeneration of Buccal Wall Defects after Tooth Extraction with Biphasic Calcium Phosphate in Injectable Form vs. Bovine Xenograft: A Randomized Controlled Clinical Trial.

Bone healing after tooth extraction may be affected by defects of the alveolus buccal wall, such as fenestrations and dehiscences. Therefore, to minimize dimensional changes it is advisable to perform alveolar ridge preservation after tooth extractions. Different biomaterials are used for this purpose. The aim of this study was to investigate the qualitative and quantitative histological changes in human biopsies taken after 6 months of healing of extraction sockets with buccal wall defects. For this purpose, the defects of 36 patients (18 per group) were treated with injectable biphasic calcium phosphate (I-BCP) or bovine xenograft (BX) after extraction. After six months of healing, biopsies were taken and proceeded to the histology laboratory. No evidence of an inflammatory response of the tissue was observed in the biopsies of either group, and the newly formed bone (NB) was in close contact with the remaining biomaterial (BM). The histomorphometric results showed that there was no statistically significant difference between the groups in the mean percentage of NB (p = 0.854), BM (p = 0.129), and soft tissue (p = 0.094). To conclude, both biomaterials exhibited osteoconductivity and biocompatibility and achieved satisfactory bone regeneration of buccal wall defects after tooth extraction.

Hydroxyapatite/calcium alginate composite particles for hemostasis and alveolar bone regeneration in tooth extraction wounds

Tooth extractions can lead to complications such as post-extraction bleeding and bone resorption, which may result in unfavorable outcomes for implant restoration afterwards. To strive for an optimal condition for further restoration procedures, appropriate strategies, such as hemostasis or bone regeneration, are encouraged to be employed. However, the existing products are failed to meet both needs. As a widely employed tissue engineering materials, hydroxyapatite and calcium alginate both have demonstrated excellent performance in osteogenesis. However, their inferior mechanical strength poses a major limitation to their use in supporting the contracted extraction socket, which can easily lead to alveolar crest atrophy and barely achieve satisfying results. Calcium alginate improves the mechanical strength of hydroxyapatite, enabling the formation of new bone tissue and degradable in vivo. In this study, we demonstrated the biocompatibility and haemostatic ability of nCA particles on a rat tooth extraction model. In addition, long-term observation has revealed minimal inflammation and bone tissue regeneration. Our findings suggest a promising insight for clinical applications in hemostasis and bone regeneration after tooth extraction.

Evaluation of Biocompatibility of New Osteoplastic Xenomaterials Containing Zoledronic Acid and Strontium Ranelate

Background. The problem of improving the functional characteristics of implanted devices and materials used in traumatology and orthopedics is a topical issue.&#x0D; Aim of the study to study biocompatibility of bovine bone matrix xenomaterials modified by zoledronic acid and strontium ranelate when implanted into the bone defect cavity.&#x0D; Methods. The study was performed on 24 male rabbits of the Soviet Chinchilla breed. Test blocks of bone matrix were implanted into the cavity of bone defects of the femur. Group 1 animals (n = 8, control group) were implanted with bone xenogenic material (Bio-Ost osteoplastic matrix). Group 2 animals (n = 8) were implanted with bone xenogenic material impregnated with zoledronic acid. Group 3 animals (n = 8) were implanted with bone xenogeneic material impregnated with strontium ranelate. Supercritical fluid extraction technology was used to purify the material and impregnate it with zoledronic acid and strontium ranelate. Radiological, pathomorphological, histological and laboratory (hematology and blood biochemistry) diagnostic methods were used to assess biocompatibility. Follow-up period was 182 days after implantation.&#x0D; Results. It was found out that on the 182nd day after implantation the median area of the newly-formed bone tissue in the defect modeling area in Group 1 was 79%, in Group 2 0%, in Group 3 67%. In Group 2 the maximum area by this period was filled with connective tissue 77%. Median relative area of implanted material fragments in Group 1 was 4%, in Group 2 23%, in Group 3 15%. No infection or material rejection was observed in animals of all groups. There were no signs of intoxication or prolonged systemic inflammatory reaction. Laboratory parameters did not change significantly over time. One animal in each group experienced one-time increase in C-reactive protein level against the background of leukocytosis. Two animals in Group 1 had a slight migration of implanted material under the skin, one animal developed arthritis of the knee joint.&#x0D; Conclusion. Osteoplastic materials based on bovine bone xenomatrix and filled with zoledronic acid and strontium ranelate have acceptable values of biocompatibility including their safety profile.

The design of strut/TPMS-based pore geometries in bioceramic scaffolds guiding osteogenesis and angiogenesis in bone regeneration

The pore morphology design of bioceramic scaffolds plays a substantial role in the induction of bone regeneration. Specifically, the effects of different scaffold pore geometry designs on angiogenesis and new bone regeneration remain unclear. Therefore, we fabricated Mg/Sr co-doped wollastonite bioceramic (MS-CSi) scaffolds with three different pore geometries (gyroid, cylindrical, and cubic) and compared their effects on osteogenesis and angiogenesis in vitro and in vivo. The MS-CSi scaffolds were fabricated by digital light processing (DLP) printing technology. The pore structure, mechanical properties, and degradation rate of the scaffolds were investigated. Cell proliferation on the scaffolds was evaluated using CCK-8 assays while angiogenesis was assessed using Transwell migration assays, tube formation assays, and immunofluorescence staining. The underlying mechanism was explored by western blotting. Osteogenic ability of scaffolds was evaluated by alkaline phosphatase (ALP) staining, western blotting, and qRT-PCR. Subsequently, a rabbit femoral defect model was prepared to compare differences in the scaffolds in osteogenesis and angiogenesis in vivo. Cell culture experiments showed that the gyroid pore scaffold downregulated YAP/TAZ phosphorylation and enhanced YAP/TAZ nuclear translocation, thereby promoting proliferation, migration, tube formation, and high expression of CD31 in human umbilical vein endothelial cells (HUVECs) while strut-based (cubic and cylindrical pore) scaffolds promoted osteogenic differentiation in bone marrow mesenchymal stem cells and upregulation of osteogenesis-related genes. The gyroid pore scaffolds were observed to facilitate early angiogenesis in the femoral-defect model rabbits while the strut-based scaffolds promoted the formation of new bone tissue. Our study indicated that the pore geometries and pore curvature characteristics of bioceramic scaffolds can be precisely tuned for enhancing both osteogenesis and angiogenesis. These results may provide new ideas for the design of bioceramic scaffolds for bone regeneration.

Major aspects of mesenchymal stem cell signaling and differentiation into osteoblasts in the optimization of bone formation for dental implant: a systematic review

Introduction: In recent decades, the number of dental implant procedures has shown significant growth worldwide, reaching about one million dental implants per year. In Brazil, in recent decades, there has been a very rapid evolution in implant dentistry with high success rates. Several materials can be used as a bone graft, each with different properties, for example, regarding neovascularization. Guided bone regeneration favors the formation of new bone tissue. When grafting procedures are required, the focus is often on the type of biomaterial to be used and the success and predictability of the results. Objective: It was to carry out a concise systematic review of bone regeneration processes using biomaterials and the main molecular and cellular constituents for implant dentistry. Methods: The survey was carried out from January to February 2023 in the Scopus, PubMed, Science Direct, and Scielo databases, using older scientific articles with a gold standard reference up to 2022. The quality of the studies was based on the GRADE instrument and the risk of bias by the Cochrane instrument. Results and Conclusion: It was founded on 128 studies that underwent eligibility analysis. The final sample had 34 eligible studies that were described in the systematic review. Most studies showed homogeneity in their results, with X2=89.8.8% &lt;50%. Due to bone regeneration and biological barriers in graft surgeries, there has been a technological growth of these materials as they point to potential tools for treating bone loss. The greater potential of guided bone regeneration was associated with the graft material due to the higher grade of vital bone and the lower percentage of residual graft particles. All studied bone substitute materials resulted in efficient bone formation for dental implants and alveolar ridge preservation procedures.

Long Bone Defect Filling with Bioactive Degradable 3D-Implant: Experimental Study

Previously, 3D-printed bone grafts made of titanium alloy with bioactive coating has shown great potential for the restoration of bone defects. Implanted into a medullary canal titanium graft with cellular structure demonstrated stimulation of the reparative osteogenesis and successful osseointegration of the graft into a single bone-implant block. The purpose of this study was to investigate osseointegration of a 3D-printed degradable polymeric implant with cellular structure as preclinical testing of a new technique for bone defect restoration. During an experimental study in sheep, a 20 mm-long segmental tibial defect was filled with an original cylindrical implant with cellular structure made of polycaprolactone coated with hydroxyapatite. X-ray radiographs demonstrated reparative bone regeneration from the periosteum lying on the periphery of cylindrical implant to its center in a week after the surgery. Cellular structure of the implant was fully filled with newly-formed bone tissue on the 4th week after the surgery. The bone tissue regeneration from the proximal and distal bone fragments was evident on 3rd week. This provides insight into the use of bioactive degradable implants for the restoration of segmental bone defects. Degradable implant with bioactive coating implanted into a long bone segmental defect provides stimulation of reparative osteogenesis and osseointegration into the single implant-bone block.

3D-Printing of succulent plant-like scaffolds with beneficial cell microenvironments for bone regeneration.

Biomimetic materials with complicated structures inspired by natural plants play a critical role in tissue engineering. The succulent plants, with complicated morphologies, show tenacious vitality in extreme conditions due to the physiological functions endowed by their unique anatomical structures. Herein, inspired by the macroscopic structure of succulent plants, succulent plant-like bioceramic scaffolds were fabricated via digital laser processing 3D printing of MgSiO3. Compared with conventional scaffolds with interlaced columns, the structures could prevent cells from leaking from the scaffolds and enhance cell adhesion. The scaffold morphology could be well regulated by changing leaf sizes, shapes, and interlacing methods. The succulent plant-like scaffolds show excellent properties for cell loading as well as cell distribution, promoting cellular interplay, and further enhancing the osteogenic differentiation of bone marrow stem cells. The in vivo study further illustrated that the succulent plant-like scaffolds could accelerate bone regeneration by inducing the formation of new bone tissues. The study suggests that the obtained succulent plant-like scaffold featuring the plant macroscopic structure is a promising biomaterial for regulating cell distribution, enhancing cellular interactions, and further improving bone regeneration.

Procesiranje i svojstva makroporoznih nosača na bazi kalcijum-fosfata dopiranih jonima magnezijuma, bakra i cinka prevučenih želatinom

The main goal of this study was to examine the possibility for obtaining macroporous scaffolds with defined properties based on calcium phosphate doped with magnesium, copper and zinc ions, coated with gelatin, which would potentially provide controlled conditions for the formation of new bone tissue after implantation. As a first, multi-doped nanoparticles of hydroxyapatite (HAp), which represents the main component of the inorganic part of bone tissue, was synthesized by autoclaving the precursor solution obtained at a Ca/P molar ratio of 1.52. Calcium in the initial solution was partially replaced by ions of magnesium (5 mol.%), copper (0.4 mol.%) and zinc (0.4 mol.%). Obtained powder was further calcinated, the changes in the morphology of the powders during calcination at 1000 ̊ C were reflected in the transition of spherically agglomerated needle-like nanoparticles of the multi-doped hydroxy-apatite powder to a spherical grained morphology. Macroporous bioceramic structures were obtained using the sponge replica method, green macroporous samples made of calcinated multi-doped powder, polyvinyl alcohol and water were sintered at 1.370°Ϲ and 1.430°Ϲ. X-ray diffraction analysis deter-mined that the presence of magnesium in the structure of hydroxyapatite favors the phase transformation of HAp into b-tricalcium-phosphate (b-TCP), which contributed to the formation of the biphasic HAp/b-TCP system during the calcination of the powders, but also during the sintering of macroporous beads. Examination of the antimicrobial activity of the obtained macroporous supports against E. coli showed a more effective degree of inhibition compared to S. aureus. A significant increase in the compressive strength of sintered macroporous scaffolds was obtained after the formation of coating based on 7.5% gelatin solution.

Роль метаболизма кортизола в реализации патогенетических звеньев развития осте- опороза – обоснование поиска новых фар- макотерапевтических мишеней (обзор)

Background: Osteoporosis is an important medical and social public health problem in an aging or elderly society. Osteoporosis is caused by an imbalance in bone remodeling, which is a continuous process of destruction of mature bone tissue by osteoclasts (bone resorption) and the formation of new bone tissue by osteoblasts (bone formation). The system of bone homeostasis that regulates the functional activity of osteoclasts and osteoblasts is represented by a wide range of molecules. The understanding of the molecular mechanisms of bone homeostasis achieved today makes it possible to significantly change and expand the paradigms of treatment and prevention of osteoporosis. The aim of the study: To consider the main pathogenetic pathways through which the effect of the cortisol metabolism system on the development of osteoporosis is realized and to identify ways to find new therapeutic approaches to the treatment and prevention of this pathology. Materials and methods: To achieve this goal, we analyzed the literature on the influence of cortisol metabolism on the development of osteoporosis published in the last 10 years. Results: To date, there are significant prerequisites in the literature for a direct connection of disorders of steroid hormone metabolism with the development of osteoporosis and a violation of osteoreparative processes. This literature review presents the main pathogenetic pathways that cause the processes leading to a decrease in bone density in disorders of cortisol metabolism. The enzyme 11b-hydroxysteroid dehydrogenase (11b-HSD), represented by two isoforms, performs the mutual conversion of cortisone and cortisol in tissues. Using the methods of reverse genetics, we have established the systemic consequences of knockout of both isoforms. Convincing evidence demonstrates that both enzymes are involved in the pathogenesis of osteoporosis. Since animals with type 11b-HSD deficiency are characterized by proinflammatory activation of the endothelium, we assume that further study of the interaction between the endothelium and bone tissue is of particular interest. Conclusion: The effects of glucocorticoids on eNOS expression seem to be significantly modulated by 11ß-HSD isoenzymes. The established relationship between 11ß-HSD and NO can be considered a promising pharmacotherapeutic target. In this regard, a pharmacotherapeutic approach aimed at restoring the balance of nitric oxide in bone and endothelial tissues, currently considered as one of the most relevant ways to correct osteoporosis, may also be relevant in case of cortisol metabolism disorders due to 11ß-HSD2 deficiency.

Assessment of serum alkaline phosphatase and calcium levels during bone fracture healing in dogs stabilized with a bone plate after being treated with an amniotic membrane loaded with platelet rich plasma

Background/aim: The goal of the present study was to investigate the effects of an acellular amniotic membrane loaded with autologous platelet-rich plasma on bone healing biochemically by measuring serum factors including calcium and alkalinity in a dog model. Materials and methods: Fifteen dogs were used in the current study. The animals were divided into three groups of five dogs each. A transverse osteotomy was induced in the midshaft of the left tibia of all animals. The first group was treated with acellular amniotic membrane only by wrapping it around the fracture site. The second group was given acellular amniotic membrane and platelet-rich plasma to treat them, while the third group (the control) was left alone and not treatedWhole blood was drawn from all groups on the 0th day prior to surgery as well as on the 14th, 28th, 42nd, and 56th days following surgery. Physiological data was then reported. in order to estimate calcium and alkaline phosphatase at various phases of fracture healing. Results: the results of the present study illustrated that the serum alkaline phosphate and calcium levels increased (p≤0.01) on days 14 and 28, followed by a decreasing trend after day 28 to day 56. And their levels were higher in group AM+PRP than in other groups (39.4 ± 1.21, 15.79±0.66 respectively). When compared to the control and AM groups, the rate of formation of new bone tissue in Group AM+PRP was the fastest. It was concluded that serum alkaline phosphatase and calcium were found to be helpful biochemical indicators for evaluating bone development and contributed to proving the superiority of using the amniotic membrane loaded with platelet-rich plasma in promoting bone healing. These biochemical parameters, in conjunction with clinical and radiographic examinations, provide reliable information about the degree of bone healing.