Osteoid Tissue Research Articles

Aneurysmal Bone Cyst of Maxilla With Palatal Perforation: A Case Report

Aneurysmal bone cysts ABCs are infrequent osteolytic growths within the jawbone manifesting as solid hard lumps that continue to expand. These lesions are composed of vascular spaces filled with blood separated by trabecular osteoid tissue and osteoclast-type giant cells. ABC accounts for approximately 1.5 of non-odontogenic tumours found in jawbones primarily developing in the long bones. The mandible is the most frequently affected area while ABC affecting the upper maxillary bones is an uncommon entity representing a mere 2 of cases. This case report sheds light on the infrequent occurrence of ABC specifically accounting for 2 of cases. In this case a 25-year-old male presented to our department in August 2022 complaining of painless swelling in the right upper back tooth and palatal region persisting for 2 months. ABCs occurring in the jaws are rare typically affecting a younger demographic. This case report highlights a rare instance of ABC located in the posterior maxilla. Treatment involves curettage of the affected bone and in this case we performed curettage and covered the defect using palatal rotational flap.

Mobilisation and replenishment of phosphorus reserves in Bos indicus cows. 1. Mid-pregnant mature cows post-weaning

Context Lactating beef cows grazing phosphorus (P)-deficient pastures often mobilise body P to alleviate a P deficiency. Knowledge of the circumstances when body P is mobilised, and later replenished, is necessary for optimal management of the P nutrition of breeder herds. Aims To investigate mobilisation and replenishment of body P in mature Bos indicus-cross beef cows post-weaning. Methods Cows (n = 40) in their second trimester of pregnancy were individually fed ad libitum low-P (LP) or high-P (HP) diets containing moderate or high metabolisable energy (ModE-LP, HighE-LP, ModE-HP and HighE-HP) for 14 weeks. Key results Plasma inorganic P concentrations (Pi) in LP- or HP-diet cows (0.58 and 2.15 mmol/L respectively) indicated that diet P was deficient or adequate. Intakes of DM and metabolisable energy, liveweight gain, and P retention were higher (P < 0.05 to P < 0.001) in cows fed the HP diets, and were also increased in the high metabolisable-energy diets. Efficiency in use of metabolisable energy for slow growth was lower in the HighE-LP than the ModE-HP cows. The cows fed the LP diets mobilised 4–5 g body P/day. Cows fed the Mod-HP and HighE-HP diets retained 1.1 and 8.8 g body P/day, and those ModE-HP cows with low bone P reserves retained ~2.3 g P/day. Rib cortical bone P did not change in HP cows but decreased (P < 0.05) in LP cows. The HP diets increased the bone volume, mineralised bone, and the thickness of the struts in trabecular bone in the tuber coxae. Osteoid tissue decreased (P < 0.05) in HighE-HP cows. Changes in plasma concentrations of 1,25-dihydroxy vitamin D3, carboxy-terminal telopeptides of type I collagen (CTX-1) and bone alkaline phosphatase (BAP) were in accord with substantial bone mobilisation in cows fed LP diets, and bone replenishment with HP diets. Conclusions Cows that had ingested P-deficient diets during lactation were able to further mobilise body P when fed LP diets post-weaning, but cows replenished body P when fed HP diets. Implications Mature cows with low body P reserves can replenish these reserves more rapidly when consuming diets high in both P and metabolisable energy.

Results of biochemical and histological studies after restoration of bone defects using cellular technologies in dental patients

Objective of the research was to find out the effectiveness of the use of osteoplastic materials based on the multipotent mesenchymal stromal cells of the adipose tissue during surgical treatment for restoration of bone defects in dental patients. The clinical material included examination of 79 patients who underwent replacement of bone defects of the alveolar processes and/or an alveolar part of the appropriate jaw by means of different osteoplastic materials and their combinations or without their application (the control group). Acid phosphatase activity in the oral fluid of patients was determined by means of the unified “end point” method. Alkaline phosphatase activity in the oral fluid was determined using a set of reagents produced by the company “Filisit-Diagnostika” (Ukraine). Oral fluid mineralization index (MI) of patients was calculated according to the ratio of enzymatic activity of alkaline phosphatase (ALP) to acid phosphatase (AP) according to the formula: MI=ALP/AP. Histological material was taken at the stage of installation of a dental implant. It was established that the use of a composition based on multipotent mesenchymal stromal cells of adipose tissue, platelet-enriched blood plasma and bone tissue substitute containing hydroxyapatite contributes to the improvement of regenerative processes in the bone tissue of the jaws, which is confirmed by a 28.68% decrease in acid phosphatase activity, an increase by 25, 97% of alkaline phosphatase activity in the oral fluid of group B patients and, accordingly, a 77.08% increase in the ratio of alkaline to acid phosphatase. According to the results of histological studies and phase-contrast microscopy, after 6-8 months of observation, in patients of group B, the areas of jaw defects were filled with newly formed bone tissue, identical to native bone, and the resulting trepanobioptas had the structure of cancellous bone with osteoblastic elements forming a chain around osteoid tissue. Having analyzed the results of biochemical and histological studies it was established that application of an osteoplastic composition based on the multipotent mesenchymal stromal cells of the adipose tissue, bone tissue substitute with hydroxyapatite and platelet-rich plasma allows restoration of bone defects of the alveolar processes and an alveolar part of the appropriate jaw in shorter terms. The method is an optimal alternative to traditional osteoplastic materials to be used in modern dental practice and dental implantation.

An Elastin-Derived Composite Matrix for Enhanced Vascularized and Innervated Bone Tissue Reconstruction: From Material Development to Preclinical Evaluation.

Despite progress in bone tissue engineering, reconstruction of large bone defects remains an important clinical challenge. Here, a biomaterial designed to recruit bone cells, endothelial cells, and neuronal fibers within the same matrix is developed, enabling bone tissue regeneration. The bioactive matrix is based on modified elastin-like polypeptides (ELPs) grafted with laminin-derived adhesion peptides IKVAV and YIGSR, and the SNA15 peptide for retention of hydroxyapatite (HA) particles. The composite matrix shows suitable porosity, interconnectivity, biocompatibility for endothelial cells, and the ability to support neurites outgrowth by sensory neurons. Subcutaneous implantation leads to the formation of osteoid tissue, characterized by the presence of bone cells, vascular networks, and neuronal structures, while minimizing inflammation. Using a rat femoral condyle defect model, longitudinal micro-CT analysis is performed, which demonstrates a significant increase in the volume of mineralized tissue when using the ELP-based matrix compared to empty defects and a commercially available control (Collapat). Furthermore, visible blood vessel networks and nerve fibers are observed within the lesions after a period of two weeks. By incorporating multiple key components that support cell growth, mineralization, and tissue integration, this ELP-based composite matrix provides a holistic and versatile solution to enhance bone tissue regeneration.

ПРОЦЕССЫ РЕГЕНЕРАЦИИ КОСТНОЙ ТКАНИ ПРИ ПЕРЕЛОМАХ НИЖНЕЙ ЧЕЛЮСТИ

Item. The review of literature devoted to the actual problem of maxillofacial surgery — processes of bone tissue regeneration in mandibular fractures is presented. The purpose of the study — to study and analyze the materials of publications on the processes of bone tissue regeneration in mandibular fractures. Methodology. The publications of domestic and foreign authors devoted to the processes of bone tissue regeneration in mandibular fractures were studied. The publications were analyzed using scientific search library databases: PubMed Central, Google, Cyberleninka, eLibrary. Materials were selected by keywords. Full-text articles were included in the search. Results. In domestic and foreign literature, the processes of restoration of bone structures of the maxillofacial region as an organism's response to damage have been studied and described in detail. It has been established that two processes are simultaneously launched: resorption of damaged osteocytes and formation of osteoid tissue, one of which may be predominant at the moment. Conclusions. The article presents modern data on the key moments of bone tissue regeneration in the region of the mandible. All stages of the reparative process in bone tissue are described at the cellular level, and information about the main mechanisms, pathways and cell types involved in bone tissue regeneration is presented in detail, taking into account the stage of osteogenesis. Knowledge of the regularities of biological processes in the bone tissue regeneration zone allows scientific search and development of effective methods of treatment of mandibular fractures.

Optimal dual calcium and cholecalciderol dosages for osteoporotic fracture risk patients

Background: Vitamin D is crucial for musculoskeletal health, promoting calcium absorption, osteoid tissue mineralization, and muscle function. Insufficient levels can lead to bone dystrophy, muscle weakness, and osteoporotic fractures. Aims: This research investigates the correlation between bone mineral density and osteoporotic fracture risk, including positive and negative influences, and aims to determine the optimal vitamin D level. Methods: This retrospective observational study examined 206 Jordanian rehabilitation and rheumatology clinic patients from September to November 2021. The participants were post-menopausal women and men over 60. The Age-adjusted Charlson Co-Morbidity Index and Functionality Grade system was used to assess participants' co-morbidity burden and functionality. DEXA scans assessed participants' proximal femoral hip and anteroposterior spine. Participants were divided into two Vit D groups: those below 30 ng/ml and those above 30. Results were compared using a Chi Square test. The study examined correlations, total variations, and Vit D prediction quality using logistic regression analyses. SPSS 23.0 was used for statistical analysis with a 5% significance level. Results: A binary logistic regression model was employed to simulate the correlation between the vitamin D levels of patients and their bone mineral density. The model indicated a 61.39% likelihood of having a fH_BMD (femoral head bone mineral density) equal to or greater than 0.755 g/cm2 when the vitamin D level is at its optimal value of 27.25 ng/ml. The model indicated a 27.25% likelihood of a fHOPF risk-free tool with a value of ≥3% when the optimal vitamin D level is 27.25 ng/ml. The model indicated a 17.74% likelihood of experiencing a significant osteoporotic fracture within the next 10 years. Conclusion: The findings of our study demonstrated a direct correlation between elevated levels of vitamin D and improved bone mineral quality indices that were examined. The serum 25-OH Cholecalciferol levels are more likely to have a beneficial effect on bone health status.

Evaluation of biocompatibility of Commercial Pure Titanium / Bioactive Glass Ceramic Functionally Graded Material as Dental Implant Material In-Vivo study

Background: the ultimate goal of modern implantology is fine and fast osseointegration which is a major factor influencing the success of dental implantation, and the optimum circumstances of it the biointegration which is the occurrence of continuity of ceramic implant to bone without intervening space. 
 Material and method: Two groups of cylindrical implant specimens were prepared from functionally graded material and commercial pure titanium. Each group composed of 40 implant specimens. The femur of 20 white male New Zealand rabbits, were chosen as implantation sites. Push out test was performed to measure bone bonding strength between implant specimen and bone after 2 and 4 weeks healing periods (10 rabbits for each periods). For each time interval 20 implant specimens for each group, which implanted in rabbits. Histological study for evaluation of tissue response and histomorphometric analysis was performed for measurement of new bone area at two time intervals.
 Result: the results of push out force and new bone formation area appeared that mean values of functionally graded material implant specimens were a statistically highly significant more than that of commercial pure titanium implant specimens after 2 weeks and 4 weeks of implantation. In histological examination, there was an active osteoid tissue around functionally graded material implants and hematopoietic tissues around commercial pure titanium implants after 2 weeks, and there was an osteoid maturation with observation of reversal lines around functionally graded material implants and new bone formation with osteocyte around commercial pure titanium implants after 4 weeks of implantation.

Interpenetrating network hydrogels for studying the role of matrix viscoelasticity in 3D osteocyte morphogenesis.

During bone formation, osteoblasts are embedded in a collagen-rich osteoid tissue and differentiate into an extensive 3D osteocyte network throughout the mineralizing matrix. However, how these cells dynamically remodel the matrix and undergo 3D morphogenesis remains poorly understood. Although previous reports investigated the impact of matrix stiffness in osteocyte morphogenesis, the role of matrix viscoelasticity is often overlooked. Here, we report a viscoelastic alginate-collagen interpenetrating network (IPN) hydrogel for 3D culture of murine osteocyte-like IDG-SW3 cells. The IPN hydrogels consist of an ionically crosslinked alginate network to tune stress relaxation as well as a permissive collagen network to promote cell adhesion and matrix remodeling. Two IPN hydrogels were developed with comparable stiffnesses (4.4-4.7 kPa) but varying stress relaxation times (t1/2, 1.5 s and 14.4 s). IDG-SW3 cells were pre-differentiated in 2D under osteogenic conditions for 14 days to drive osteoblast-to-osteocyte transition. Cellular mechanosensitivity to fluid shear stress (2 Pa) was confirmed by live-cell calcium imaging. After embedding in the IPN hydrogels, cells remained highly viable following 7 days of 3D culture. After 24 h, osteocytes in the fast-relaxing hydrogels showed the largest cell area and long dendritic processes. However, a significantly larger increase of some osteogenic markers (ALP, Dmp1, hydroxyapatite) as well as intercellular connections via gap junctions were observed in slow-relaxing hydrogels on day 14. Our results imply that fast-relaxing IPN hydrogels promote early cell spreading, whereas slow relaxation favors osteogenic differentiation. These findings may advance the development of 3D in vivo-like osteocyte models to better understand bone mechanobiology.

Repair of Osteoporotic Bone Defects in Rats via the Sirtuin 1-Wnt/β-catenin Signaling Pathway by Novel Icariin/Porous Magnesium Alloy Scaffolds.

The slow rate of bone regeneration and repair in osteoporotic defects is one of the difficulties of clinical work. To prepare a novel icariin (ICA)/porous magnesium alloy scaffold and to investigate its effectiveness and possible mechanism in repairing osteoporotic bone defects, bilateral ovariectomy was performed on Sprague-Dawley rats. Then, a cylindrical bone defect was created in the model, and a novel ICA/porous magnesium alloy scaffold was prepared and implanted into the defect. Eight or 12 weeks after repairing, specimens and micro-computed tomography (CT) data were collected. Microscopic observation was fulfilled through hematoxylin and eosin, Goldner, Masson, periodic acid-Schiff, and Sirius red staining. The expression of proteins was detected by immunohistochemical staining. The novel ICA/porous magnesium alloy scaffold was noncytotoxic and biologically safe. After it was implanted into the defect for 8 or 12 weeks, the surface color and smoothness, depth, and area of the defect were better than those in the control group. Besides, there was sufficient osteoid tissue, more mineralized bones, more collagen fibers, and more polysaccharide components in the defect repaired with the ICA/porous magnesium alloy scaffold. These conditions are closer to those of real bones. Moreover, the repair effect improved with the repair time. Compared with those in the control group, the expression levels of Sirtuin 1(SIRT1), Wnt5a, β-catenin, glycogen synthase kinase 3β, alkaline phosphatase, runt-related transcription factor 2, bone morphogenetic protein-2, and osteocalcin proteins were elevated in bone tissue after the scaffold was implanted into the defect for 8 weeks (all P < 0.05). The novel ICA/porous magnesium alloy scaffold promotes the repair of osteoporotic bone defects in rats, a process that may be achieved through activation of the SIRT1-Wnt/β-catenin signaling pathway.

Tuning Physical Properties of GelMA Hydrogels through Microarchitecture for Engineering Osteoid Tissue.

Gelatin methacryloyl (GelMA) hydrogels have gained significant attention due to their biocompatibility and tunable properties. Here, a new approach to engineer GelMA-based matrices to mimic the osteoid matrix is provided. Two cross-linking methods were employed to mimic the tissue stiffness: standard cross-linking (SC) based on visible light exposure (VL) and dual cross-linking (DC) involving physical gelation, followed by VL. It was demonstrated that by reducing the GelMA concentration from 10% (G10) to 5% (G5), the dual-cross-linked G5 achieved a compressive modulus of ∼17 kPa and showed the ability to support bone formation, as evidenced by alkaline phosphatase detection over 3 weeks of incubation in osteogenic medium. Moreover, incorporating poly(ethylene) oxide (PEO) into the G5 and G10 samples was found to hinder the fabrication of highly porous hydrogels, leading to compromised cell survival and reduced osteogenic differentiation, as a consequence of incomplete PEO removal.

Bottom-Up Extrusion-Based Biofabrication of the Osteoid Niche.

Bone regeneration remains a clinical challenge given the transplantation incidence rate and the associated economic burden. Bottom-up osteoid tissue engineering has the potential to offer an alternative approach to current clinical solutions that suffer from various drawbacks. In this paper, deposition-based bioprinting is exploited while the effect is explored of both the crosslinking mechanism (gelatin methacryloyl (GelMA) versus gelatin norbornene (DS 91) crosslinked with thiolated gelatin (GelNBSH)) and the degree of substitution (GelNBSH versus norbornene-norbornene-modified gelatin (DS 169) crosslinked with thiolated gelatin (GelNBNBSH)) on the presented biophysical cues as well as on the osteogenic differentiation. The incorporation of tris(2-carboxyethyl)phosphine (TCEP) to the step-growth inks allows the production of reproducible and biocompatible scaffolds based on thiol-ene chemistry. Dental pulp stem cell encapsulation in GelNBNBSH biofabricated constructs shows a favorable response due to the combination of its stress relaxation and substrate rigidity (bulk compressive modulus of 11-30kPa) as reflected by a sevenfold increase in calcium production compared to the tissue engineering standard GelMA. This work is the first to exploit a controlled biocompatible and cell-interactive thiolated macromolecular crosslinker (GelSH + TCEP) allowing the extrusion-based biofabrication of low concentration (5 w/v%) modified osteogenic gelatin-based inks (GelNBNBSH + TCEP).

Development and characterization of islet-derived mesenchymal stem cells from clinical grade neonatal porcine cryopreserved islets.

Porcine tissues display a great potential as donor tissues in xenotransplantation, including cell therapy. Cryopreserving clinical grade porcine tissue and using it as a source for establishing therapeutic cells should be advantageous for transportation and scheduled manufacturing of MSCs. Of note, we previously performed encapsulated porcine islet transplantation for the treatment of unstable type 1 diabetes mellitus in the clinical setting. It has been reported that co-transplantation of islets and Mesenchymal stem cells (MSCs) enhanced efficacy. We assume that co-transplantation of porcine islets and porcine islet-derived MSCs could improve the efficacy of clinical islet xenotransplantation. MSCs were established from fresh and cryopreserved non-clinical grade neonatal porcine islets and bone marrow (termed non-clinical grade npISLET-MSCs and npBM-MSCs, respectively), as well as from cryopreserved clinical grade neonatal porcine islets (termed clinical grade npISLET-MSCs). Subsequently, the cell proliferation rate and diameter, surface marker expression, adipogenesis, osteogenesis, and colony-forming efficiency of the MSCs were assessed. Cell proliferation rate and diameter did not differ between clinical grade and non-clinical grade npISLET-MSCs. However, non-clinical grade npBM-MSCs were significantly shorter and smaller than both npISLET-MSCs (p<0.05). MSC markers (CD29, CD44, and CD90) were strongly expressed in clinical grade npISLET-MSCs and non-clinical grade npISLET-MSCs and npBM-MSCs. The expression of MSC-negative markers CD31, CD34, and SLA-DR was low in all MSCs. Clinical grade npISLET-MSCs derived from adipose and osteoid tissues were positive for Oil Red and alkaline phosphatase staining. The results of colony-forming assay were not significantly different between clinical grade npISLET-MSCs and non-clinical grade npBM-MSCs. The method described herein was successful in of developing clinical grade npISLET-MSCs from cryopreserved islets. Cryopreserved clinical grade porcine islets could be an excellent stable source of MSCs for cell therapy.

Nano selenium-doped TiO2 nanotube arrays on orthopedic implants for suppressing osteosarcoma growth.

Osteosarcoma, the most common primary malignant bone tumor, is characterized by malignant cells producing osteoid or immature bone tissue. Most osteosarcoma patients require reconstructive surgery to restore the functional and structural integrity of the injured bone. Metal orthopedic implants are commonly used to restore the limb integrity in postoperative patients. However, conventional metal implants with a bioinert surface cannot inhibit the growth of any remaining cancer cells, resulting in a higher risk of cancer recurrence. Herein, we fabricate a selenium-doped TiO2 nanotube array (Se-doped TNA) film to modify the surface of medical pure titanium substrate, and evaluate the anti-tumor effect and biocompatibility of Se-doped TNA film. Moreover, we further explore the anti-tumor potential mechanism of Se-doped TNA film by studying the behaviors of human osteosarcoma cells in vitro. We provide a new pathway for achieving the anti-tumor function of orthopedic implants while keeping the biocompatibility, aiming to suppress the recurrence of osteosarcoma.

Feline osteochondromatosis in a 12-year-old feline leukaemia virus-negative cat

Feline osteochondromatosis is a spontaneous osteocartilaginous exostosis associated with feline leukaemia virus (FeLV) infection or due to a frameshift variant in the exostosin glycosyltransferase 1 (EXT1) gene. Osteochondromatosis was diagnosed in an indoor-only, 12-year-old, neutered female, Russian Blue cat. Radiographs revealed bilateral calcified proliferations in the elbow, costochondral and sternochondral joints, which distorted the normal skeletal structure. Grossly, the proliferated joints presented with consistent, rounded masses, causing complete ankylosis. The main histopathological finding was an osteocartilaginous proliferation composed of multiple irregular islands of well-differentiated hyaline cartilage surrounded and delimited by osteoid tissue. Immunohistochemistry of the osteochondromas, bone marrow and mediastinal lymph nodes, using a primary anti-FeLV gp70 antibody, and FeLV proviral DNA real-time polymerase chain reaction on bone marrow were negative. Sequencing of exon 6 of the EXT1 gene was performed and nucleotide BLAST analysis demonstrated the absence of a frameshift variant. This study reports the only case of spontaneous feline osteochondromatosis in an animal more than 10 years old.

Central odontogenic fibroma: A case report

The central odontogenic fibroma (COF) is a rare benign odontogenic mesenchymal tumour of jaw bone derived from the odontogenic ectomesenchyme. It is characterized by a fibrous mature stroma with variable number of strands or islands of inactive-looking odontogenic epithelium. The presented case is a 46 years old male complaining of asymptomatic mandibular bony swelling. Radiographically, the lesion is unilocular radiolucent, with root resorption and displacement of teeth. Histopathology showed dense fibrous connective tissue stroma, loosely arranged with spindle and stellate-shaped mesenchymal cells, inactive odontogenic epithelium island and osteoid tissue. In this case report, we also discuss about the types, pathogenesis, and recent concepts regarding COF.

Biphasic calcium phosphate doped with zirconia nanoparticles for reconstruction of induced mandibular defects in dogs: cone-beam computed tomographic and histopathologic evaluation

The present study aimed to evaluate osteogenic potential and biocompatibility of combining biphasic calcium phosphate with zirconia nanoparticles (4Zr TCP/HA) compared to biphasic calcium phosphate (TCP/HA) for reconstruction of induced mandibular defects in dog model. TCP/HA and 4Zr TCP/HA scaffolds were prepared. Morphological, physicochemical, antibacterial, cytocompatibility characterization were tested. In vivo application was performed in 12 dogs where three critical-sized mandibular defects were created in each dog. Bone defects were randomly allocated into: control, TCP/HA, and 4Zr TCP/HA groups. Bone density and bone area percentage were evaluated at 12 weeks using cone-beam computed tomographic, histopathologic, histomorphometric examination. Bone area density was statistically increased (p < 0.001) in TCP/HA and 4Zr TCP/HA groups compared to control group both in sagittal and coronal views. Comparing TCP/HA and 4Zr TCP/HA groups, the increase in bone area density was statistically significant in coronal view (p = 0.002) and sagittal view (p = 0.05). Histopathologic sections of TCP/HA group demonstrated incomplete filling of the defect with osteoid tissue. Doping with zirconia (4Zr TCP/HA group), resulted in statistically significant increase (p < 0.001) in bone formation (as indicated by bone area percentage) and maturation (as confirmed by Masson trichrome staining) compared to TCP/HA group. The newly formed bone was mature and organized with more trabecular thickness and less trabecular space in between. Physicochemical, morphological and bactericidal properties of combining zirconia and TCP/HA were improved. Combining zirconia and TCP/HA resulted in synergistic action with effective osteoinduction, osteoconduction and osteointegration suggesting its suitability to restore damaged bone in clinical practice.Graphical

Validierung des Lower Extremity Early Rehabilitation Score-13 (LERAS-13) – Ein neuer Fragebogen für die frühe Rehabilitationsphase nach Verletzungen der unteren Extremitäten

The performance of the porous glass ceramic doped with 10 wt% Zinc and 2 wt% TiN (46S6-10Zn), in the restoration of critical diaphyseal bone defect, was evaluated by several physicochemical methods and histological studies. The critical defect in rabbits was created and then filled with 46S6-10Zn. At different periods after implementation, animals were sacrificed. Samples were harvested for exploration. The nuclear magnetic resonance (MAS-NMR) of 31P and 29Si illustrates the progressive degradation of 46S6-10Zn in favor to of the formation and the development of biological apatite. Therefore, after one month of implementation, MAS-NMR 29Si proves the presence of Q2 (25%), Q3 (73%) and Q4 (2%). However, after six months, the disappearance of all these species was revealed and characterized by the 46S6-10Zn dissolution. Besides, MAS-NMR 31P demonstrates the presence of QC0 (4%), QHA0 (55%) and Qa0 (41%) after one month. Nevertheless, six months later, we observe the presence of QHA0 (80%) and Qa0 (20%). Histological study demonstrates an intimate contact of 46S6-10Zn surrounding bone after one month of implantation. However, after four months, mature bone matrix became calcified and the implanted 46S6-10Zn began to be degraded. Moreover, nine months later, 46S6-10Zn was nearly resorbed and replaced by a calcified tissue in the periphery and an osteoid tissue in the middle of bone defects.

Angiogenesis coupled with osteogenesis in a bone tissue engineering scaffold enhances bone repair in osteoporotic bone defects

Increased life expectancy has resulted in an increase in osteoporosis incidence worldwide. The coupling of angiogenesis and osteogenesis is indispensable for bone repair. Although traditional Chinese medicine (TCM) exerts therapeutic effects on osteoporosis, TCM-related scaffolds, which focus on the coupling of angiogenesis and osteogenesis, have not yet been used for the treatment of osteoporotic bone defects. Panax notoginseng saponin (PNS), the active ingredient of Panax notoginseng, was added to a poly (L-lactic acid) (PLLA) matrix. Osteopractic total flavone (OTF), the active ingredient of Rhizoma Drynariae, was encapsulated in nano-hydroxyapatite/collagen (nHAC) and added to the PLLA matrix. Magnesium (Mg) particles were added to the PLLA matrix to overcome the bioinert character of PLLA and neutralize the acidic byproducts generated by PLLA. In this OTF-PNS/nHAC/Mg/PLLA scaffold, PNS was released faster than OTF. The control group had an empty bone tunnel; scaffolds containing OTF:PNS = 100:0, 50:50, and 0:100 were used as the treatment groups. Scaffold groups promoted new vessel and bone formation, increased the osteoid tissue, and suppressed the osteoclast activity around osteoporotic bone defects. Scaffold groups upregulated the expression levels of angiogenic and osteogenic proteins. Among these scaffolds, the OTF-PNS (50:50) scaffold exhibited a better capacity for osteogenesis than the OTF-PNS (100:0 and 0:100) scaffolds. Activation of the bone morphogenic protein (BMP)-2/BMP receptor (BMPR)-1A/runt-related transcription factor (RUNX)-2 signaling pathway may be a possible mechanism for the promotion of osteogenesis. Our study demonstrated that the OTF-PNS/nHAC/Mg/PLLA scaffold could promote osteogenesis via the coupling of angiogenesis and osteogenesis in osteoporotic rats with bone defects, and activating the BMP-2/BMPR1A/RUNX2 signaling pathway may be an osteogenesis-related mechanism. However, further experiments are necessary to facilitate its practical application in the treatment of osteoporotic bone defects.

Repair of critical-sized bone defects in rabbit femurs using graphitic carbon nitride (g-C3N4) and graphene oxide (GO) nanomaterials

Various biomaterials have been evaluated to enhance bone formation in critical-sized bone defects; however, the ideal scaffold is still missing. The objective of this study was to investigate the in vitro and in vivo regenerative capacity of graphitic carbon nitride (g-C3N4) and graphene oxide (GO) nanomaterials to stimulate critical-sized bone defect regeneration. The in vitro cytotoxicity and hemocompatibility of g-C3N4 and GO were evaluated, and their potential to induce the in vitro osteogenesis of human fetal osteoblast (hFOB) cells was assessed using qPCR. Then, bone defect in femoral condyles was created in rabbits and left empty as control or filled with either g-C3N4 or GO. The osteogenesis of the different implanted scaffolds was evaluated after 4, 8, and 12 weeks of surgery using X-ray, computed tomography (CT), macro/microscopic examinations, and qPCR analysis of osteocalcin (OC) and osteopontin (OP) expressions. Both materials displayed good cell viability and hemocompatibility with enhanced collagen type-I (Col-I), OC, and OP expressions of the hFOB cells. Compared to the control group, the bone healing process in g-C3N4 and GO groups was promoted in vivo. Moreover, complete healing of the bone defect was observed radiologically and grossly in g-C3N4 implanted group. Additionally, g-C3N4 implanted group showed higher percentages of osteoid tissue, mature collagen, biodegradation, and expressions of OC and OP. In conclusion, our results revealed that g-C3N4 and GO nanomaterials could induce osteogenesis in critical-sized bone defects.

A CASE REPORT OF SOLITARY GINGIVAL OVERGROWTH IN A YOUNG FEMALE PATIENT

Gingiva is a common site of reactive lesions in the oral cavity. Peripheral ossifying broma is a relatively uncommon gingival overgrowth that is histopathologically characterized by discrete formation of osteoid tissue and dystrophic calcication within the connective tissue. This article presents a case report of a 33 year old female with a gingival hyperplastic growth in the maxillary anterior region, in which the consistent clinical and microscopic ndings led to the diagnosis of the lesion as peripheral ossifying broma.