Osteogenesis Process Research Articles

Morphological Characteristics of the Ulna Fracture Zone in Rats Undergoing Therapy With Modified Mesenchymal Stem Cells in Experimental Osteoporosis

Osteoporosis is a progressive systemic disease characterized by a decrease in bone density. This leads to increased bone fragility and a higher likelihood of fractures. New approaches to cellular therapy have been developed for the effective treatment of this pathology, based on the use of modified osteophilic polymers with mesenchymal stem cells (MSCs) for local action on damaged bone areas. The aim of the study was to morphologically assess the effectiveness of modified osteophilic polymer MSCs on reparative osteogenesis processes during the post-traumatic period in animals with a fracture of the ulna and underlying osteoporosis. Material and methods. The experiment involved Wistar rats (females, n=40; 200–300 g, 3 months old). Osteoporosis was simulated by bilateral ovariectomy, and the fracture was simulated through diaphysis osteotomy of the ulna. All rats were randomly distributed into four groups: Group I (control, n=10; buffered solution); Group II (n=10; osteophilic polymer, 1 mg/ml); Group III (n=10; MSC suspension, 1×106); Group IV (n=10; modified osteophilic polymer MSCs, 1×106). The experiment results were evaluated in 1 and 6 months after the fracture. Results. MSCs were applied after exposure to the osteophilic polymer to restore the pool of osteoblast precursors in the fracture area of the ulna in experimental osteoporosis. In all animals, regeneration foci with varying degrees of structural and functional maturation of cellular and intercellular substrates were formed in the fracture area. The most pronounced processes of bone tissue restoration were observed with the use of modified osteophilic polymer MSCs. This is likely associated with the high concentration of modified osteophilic polymer MSCs and their retention in zones of damaged bone regeneration, subsequently stimulating osteogenesis. The paradigm of provisionality, as a universal model manifestating histogenesis and organogenesis, was utilized to gain a more comprehensive biological understanding and interpretation of the observed changes. Conclusion. MSCs applied after exposure to an osteophilic polymer significantly enhance the process of reparative osteogenesis in fractures of long bones in patients with estrogen-induced osteoporosis, thus making this technology promising for combined therapy.

The effect of exogenous and genetic factors on a decrease in bone mineral density in children with cystic fibrosis

Osteoporosis is acomplication of cystic fibrosis, the relevance of studying which is associated with an increase in the life expectancy of patients and an increase in the proportion of adults in the general patient population. The aim of the research is to study exogenous and genetic factors of bone mineral density reduction in patients with cystic fibrosis and healthy children. Methods. 100 children with cystic fibrosis and 61 healthy children over 6 years old were examined. All children underwent X-ray densitometry with the DEXXUM device (South Korea). Vitamin D intake, dietary calcium intake and physical activity were assessed using aquestionnaire. Vitamin D levels were assessed by enzyme immunoassay based on the blood content of its intermediate metabolite 25(OH)D. The determination of biochemical parameters was carried out in the CMD laboratory using the enzyme immunoassay method. Polymorphisms of the VDR, COL1A1, and CALCR genes were analyzed by restriction analysis (PDRF). Results. It was found that patients with CF (38%) are more likely to have low BMD compared with healthy children (18%). Low indicators of nutritional status had anegative impact on the BMD. The processes of osteoresorption prevail over the processes of osteogenesis in CF. The features of the course of the disease neutralize the influence of genetic factors that have been identified in healthy children. The effect of dietary calcium intake was significant for healthy children and had no effect on BMD in patients with CF, since patients adhere to acalcium-enriched diet. The effect of the CALCR and COL1A1 genes and dietary calcium intake on the BMD of healthy children has been established. Conclusion. In cystic fibrosis, the leading risk factors for decreased bone mineral density are: ahistory of meconium ileus, chronic infection with Pseudomonas aeruginosa, low nutritional status, and decreased pulmonary function (FEV1,% predicted). For healthy children, the influence of the CALCR and COL1A1 genes and dietary calcium intake are significant.

Calcium-based nanowires for bone repair

Abstract Bone defects due to the older population, severe trauma, congenital malformations, resection of bone tumors, and infections are serious problems faced in orthopedic clinical treatment, posing great hazards to human health and life, and external interventions are generally required to promote bone healing. Considering the osteogenic promotion of calcium ions, Ca-POM nanowires were synthesized in this study to facilitate the osteogenesis process through the release of calcium ions. The cytotoxicity test showed that the material possesses good biocompatibility. Furthermore, the Alizarin Red S staining demonstrated that the material could promote osteogenesis, indicating its potential as an ideal candidate for bone repair.

Secretion of osteocalcin in chitosan–hydroxyapatite scaffold with seeding of cryopreserved human adipose derived mesenchymal stem cells

Background: Tissue engineering has developed in recent years, including the utilization of bone graft to regenerate bone. The incorporation of chitosan and hydroxyapatite as scaffolds improves osteoconductive ability. Human adipose derived mesenchymal stem cells (hADMSCs) potentially differentiate into osteoblasts and can accelerate the osteogenesis process. Purpose: To determine osteocalcin secretion on chitosan-hydroxyapatite (CS-HA) scaffold with seeding of cryopreserved hADMSCs in vitro Method: Thawing was conducted on frozen (hADMSCs) and characterized using immunocytochemistry. HADMSCs were seeded on CS-HA scaffolds. Examination of osteocalcin secretion levels was carried out by collecting cell culture supernatants of hADMSCs on 7th, 14th and 21st day of the observation group by using osteocalcin ELISA kit. Result: Scanning observation (SEM) proved that the chitosan-hydroxyapatite scaffold has a suitable pore structure, because hADMSCs can attach and differentiate when attached to the porosity of the scaffold. There were significant differences in osteocalcin secretion on days 7, 14 and 21 according to the ELISA results. Conclusion: The presence of bone regeneration process in chitosan-hydroxyapatite scaffold. This was characterized by significant osteocalcin secretion on 7th, 14th and 21st day. So it can be concluded that the scaffold is compatible.

Radiographic evaluation of the healing process of alveolar abscess through regulation of VEGF and angiogenesis

Objectives: This review article aims to explain how the regulation of vascular endothelial growth factor (VEGF) and angiogenesis on alveolar abscess healing process evaluation using radiograph. Review: The databases used in this review are Google Scholar, PubMed, and Science Direct. A total of 1280 search results appeared based on keywords. The search results were selected by title and abstract according to their relevance to the review topic. A total of 24 literatures were reviewed. The alveolar bone destruction is one of the signs of an inflammatory lesion in the alveolar bone. Bone damage that occurs in cases of the abscess will reduce the absorption of x-rays thereby giving a radiolucent appearance on radiographic examination. A radiographic examination is a supporting examination that can be used to develop the healing process. The processes of angiogenesis and osteogenesis of bone homeostasis will complement each other for the bone healing process, while VEGF is a growth factor that can increase the expression of BMPs and osteoblast differentiation so that the bone healing process can take place properly. Conclusion: VEGF plays a significant role in both bone healing and regulation of vascular development and angiogenesis. However, excessive VEGF can also be harmful to the process of bone repair because it can stimulate the recruitment of osteoclasts. Therefore, VEGF regulation has an important role in apical abscess healing, and radiographic images that are quantitatively analyzed can be used to quantify this healing process.

Effect of Scaffold Geometrical Structure on Macrophage Polarization during Bone Regeneration Using Honeycomb Tricalcium Phosphate.

The polarization balance of M1/M2 macrophages with different functions is important in osteogenesis and bone repair processes. In a previous study, we succeeded in developing honeycomb tricalcium phosphate (TCP), which is a cylindrical scaffold with a honeycomb arrangement of straight pores, and we demonstrated that TCP with 300 and 500 μm pore diameters (300TCP and 500TCP) induced bone formation within the pores. However, the details of the influence of macrophage polarization on bone formation using engineered biomaterials, especially with respect to the geometric structure of the artificial biomaterials, are unknown. In this study, we examined whether differences in bone tissue formation due to differences in TCP geometry were due to the polarity of the assembling macrophages. Immunohistochemistry for IBA-1, iNOS, and CD163 single staining was performed. The 300TCP showed a marked infiltration of iNOS-positive cells, which are thought to be M1 macrophages, during the osteogenesis process, while no involvement of CD163-positive cells, which are thought to be M2 macrophages, was observed in the TCP pores. In addition, 500TCP showed a clustering of iNOS-positive cells and CD163-positive cells at 2 weeks, suggesting the involvement of M2 macrophages in the formation of bone tissue in the TCP pores. In conclusion, we demonstrated for the first time that the geometrical structure of the artificial biomaterial, i.e., the pore size of honeycomb TCP, affects the polarization of M1/2 macrophages and bone tissue formation in TCP pores.

Exploring the relationship between pyroptosis and inflammatory bone loss: Evidence from a cigarette smoke-induced osteoporosis mouse model

Smoking is by far one of the greatest public health threats and is recognized as an important predisposing factor for osteoporosis. Exposure to cigarette smoke (CS) has been reported to be associated with inflammation-associated diseases through the induction of pyroptosis. Nevertheless, the correlation between pyroptosis and bone loss induced by CS remains uninvestigated. Here, a mouse model of mainstream smoke exposure-induced osteoporosis was established. μCT, biomechanical testing, and immunohistochemical staining of bone tissue were used to assess the deleterious effects of CS on bone metabolism. In vitro, the effects of cigarette smoke extracts (CSE) on mouse primary bone marrow-derived mesenchymal stem cells (BMSCs) were tested by cell viability assays, gene and protein expression assays, and alizarin red staining. The utilization of the pyroptosis inhibitor MCC950 served to confirm the critical role of BMSCs pyroptosis in CS-induced osteoporosis. Our results indicated that exposure to mainstream smoke led to a notable decrease in the quantity of osteoblasts and hindered the process of osteogenic differentiation in mice. Additionally, there was a significant increase in the expression of pyroptosis-related proteins in the bone marrow. The inhibitory effects of CSE on cell viability and osteogenic differentiation of BMSCs were found to be dose-dependent in vitro. However, the presence of the pyroptosis inhibitor MCC950 significantly improved the impaired osteogenic differentiation and bone mineralization caused by CSE. These results highlight the crucial involvement of BMSCs pyroptosis in the development of bone loss induced by CS. In summary, the findings of this study provide novel evidence that CS exerts a detrimental effect on the process of osteogenesis in BMSCs through the induction of pyroptosis, ultimately leading to bone loss. Inhibition of pyroptosis effectively attenuated the toxicological effects of CS on BMSCs, providing a new target for preventing inflammatory osteoporosis.

Sensory-Motor-Oral Stimulation Combined with Early Sucking During the Mandibular Distraction Osteogenesis Process in Children with Robin Sequence.

To describe the findings of children with Robin Sequence (RS) who received sensory-motor-oral stimulation combined with early sucking during mandibular distraction osteogenesis (MDO), compared with children who did not receive the intervention. A quasi-experimental study. Setting: A tertiary public hospital. Patients: Children with RS referred to MDO. A historical group from the same population but managed according to the institution's standard protocol (no sucking) served as a control group. Interventions: Sensory-motor-oral stimulation, including sucking, starting 24 h after MDO (intervention group). Main Outcome Measure: Our hypothesis is that sensory-motor-oral stimulation, including sucking during the DOM process, do not negatively affect surgical outcomes. Twenty-nine children were included. Eight (72.7%) of the 11 patients in the intervention group and 13 (72.2%) of the 18 controls had MDO complications, with no significant difference between the groups (p = 1.000). The most common surgical outcome was antibiotic therapy for surgical site infection (76.2%). Six months after MDO, 22 (75.9%) children attained full oral feeding or associated with alternative feeding methods. The intervention group did not have higher complication rates, from a surgical point of view, than control group. The protocol adopted by some centers that contraindicates sucking during MDO should be revised to consider the benefits of such stimulation. Keywords: Pierre Robin Syndrome, deglutition, therapeutics, child development.

Correlating Material Properties to Osteoprotegerin Expression on Nanoparticulate Mineralized Collagen Glycosaminoglycan Scaffolds.

Precision material design directed by cell biological processes represents a frontier in developing clinically translatable regenerative technologies. While understanding cell-material interactions on multipotent progenitor cells yields insights on target tissue differentiation, equally if not more important is the quantification of indirect multicellular interactions. In this work, the relationship of two material properties, phosphate content and stiffness, of a nanoparticulate mineralized collagen glycosaminoglycan scaffold (MC-GAG) in the expression of an endogenous anti-osteoclastogenic secreted protein, osteoprotegerin (OPG) by primary human mesenchymal stem cells (hMSCs) is evaluated. The phosphate content of MC-GAG requires the type III sodium phosphate symporter PiT-1/SLC20A1 for OPG expression, correlating with β-catenin downregulation, but is independent of the effects of phosphate ion on osteogenic differentiation. Using three stiffness MC-GAG variants that do not differ significantly by osteogenic differentiation, it is observed that the softest material elicited ≈1.6-2 times higher OPG expression than the stiffer materials. Knockdown of the mechanosensitive signaling axis of YAP, TAZ, β-catenin and combinations thereof in hMSCs on MC-GAG demonstrates that β-catenin downregulation increases OPG expression by 1.5-fold. Taken together, these data constitute a roadmap for material properties that can used to suppress osteoclast activation via osteoprotegerin expression separately from the anabolic processes of osteogenesis.

Formulation of a Novel Hesperetin-Loaded Nanoemulsion and Its Promising Effect on Osteogenesis.

Alternative therapies associating natural products and nanobiotechnology show new perspectives on controlled drug release. In this context, nanoemulsions (NEs) present promising results for their structural design and properties. Hesperetin (HT), a flavonoid mainly found in citrus fruits, presents highlighted bone benefits. In this context, we developed a hesperetin-loaded nanoemulsion (HT-NE) by sonication method and characterized it by dynamic light scattering, analyzing its encapsulation efficiency, and cumulative release. The biocompatibility in human osteoblasts Saos-2-like was evaluated by the cytotoxicity assay and IC50. Then, the effects of the HT-NE on osteogenesis were evaluated by the cellular proliferation, calcium nodule formation, bone regulators gene expression, collagen quantification, and alkaline phosphatase activity. The results showed that the formulation presented ideal values of droplet size, polydispersity index, and zeta potential, and the encapsulation efficiency was 74.07 ± 5.33%, showing a gradual and controlled release. Finally, HT-NE was shown to be biocompatible and increased cellular proliferation, and calcium nodule formation, regulated the expression of Runx2, ALPL, and TGF-β genes, and increased the collagen formation and alkaline phosphatase activity. Therefore, the formulation of this NE encapsulated the HT appropriately, allowing the increasing of its effects on mechanisms to improve or accelerate the osteogenesis process.

Influence of immunodeficiency on spring-assisted cranioplasty: A study in mice

BackgroundSpring-assisted cranioplasty has been widely used in craniomaxillofacial surgery in recent years, but the molecular mechanisms that regulate the process of spring-assisted distraction osteogenesis are still unclear. The study aimed to investigate the influence of immunodeficiency on spring-assisted distraction osteogenesis. MethodsThe experimental group consisted of Thirty-six 6-week-old male scid-beige mice and the control group consisted of Thirty-six wild-type mice. All mice conducted spring-assisted cranioplasty with a distraction force of 10 g. The sagittal suture tissue of mice was obtained at 6 time points: Immediately after surgery, 1, 3, 7, 14, and 28 days after surgery. The width of the sagittal suture was measured and osteogenesis was observed through HE staining and Masson staining. The expression levels of OPG, RANKL, and IL-6 were detected through immunohistochemistry and RT-PCR. ResultsThe control group had the widest sagittal suture gap on the 3rd postoperative day, and then the gap narrowed to exceed the preoperative level. The experimental group had the widest sagittal suture gap on the 7th postoperative day, and then the gap narrowed and reached the preoperative level. Histological staining showed that the experimental group showed slower growth of skull tissue. Immunohistochemistry showed that the percentage of positive cells for OPG, RANKL, and IL-6 in the experimental group increased and decreased later than that of the control group, and the magnitude of change was smaller. RT-PCR showed that the mRNA expression levels of OPG, RANKL, and IL-6 in the experimental group exhibited a smaller increase, lower peak levels, and a delayed time to reach peak expression. These differences were statistically significant (P<0.05). ConclusionsDuring the process of spring-assisted cranioplasty, immunodeficient mice had lagging bone reconstruction responses and poor osteogenic ability. Immunologic factors, especially lymphocytes, may play an important regulatory role in the distraction osteogenesis process.

Magnesium implants with alternating magnetic field-enhanced hydrogen release and proton depletion for anti-infection treatment and tissue repair

Implant-related osteomyelitis is a formidable hurdle in the clinical setting and is characterized by inflammation, infection, and consequential bone destruction. Therefore, effective reactive oxygen species (ROS) scavenging, bacterial killing, and subsequent bone tissue repair are urgently needed for the treatment of difficult-to-heal osteomyelitis. Herein, we utilized the eddy-thermal effect of magnesium (Mg) implants under an alternating magnetic field (AMF) for the controlled release of H2 gas and ions (OH− and Mg2+) for the treatment of osteomyelitis. H2 released by Mg rods under AMFs effectively scavenged cytotoxic ROS, exhibiting anti-inflammatory effects and consequently disrupting the environment of bacterial infections. In addition, the OH− hindered the energy metabolism of bacteria by effectively neutralizing protons within the microenvironment. Moreover, H2 impaired the permeability of bacterial membranes and expedited the damage induced by OH−. This synergistic AMF-induced H2 and proton depletion treatment approach not only killed both gram-negative and gram-positive bacteria but also effectively treated bacterial infections (abscesses and osteomyelitis). Moreover, Mg2+ released from the Mg rods enhanced and accelerated the process of bone osteogenesis. Overall, our work cleverly exploited the eddy-thermal effect and chemical activity of Mg implants under AMFs, aiming to eliminate the inflammatory environment and combat bacterial infections by the simultaneous release of H2, OH−, and Mg2+, thereby facilitating tissue regeneration. This therapeutic strategy achieved multiple benefits in one, thus presenting a promising avenue for clinical application.

СРАВНИТЕЛЬНАЯ ХАРАКТЕРИСТИКА МЕТОДОВ ИММОБИЛИЗАЦИИ ОТЛОМКОВ ПРИ ПЕРЕЛОМАХ НИЖНЕЙ ЧЕЛЮСТИ

Item. A review of the literature is presented on the current problem of maxillofacial surgery – methods of fixation of bone fragments in fractures of the lower jaw. The purpose of the study is to study publications on methods of fixation of fragments in fractures of the lower jaw in the comparative aspect of their influence on the clinical course. Methodology. The publications of domestic and foreign authors on modern methods of fixation of bone fragments in fractures of the lower jaw were studied, and a comparative analysis of their effectiveness was carried out. Results. Currently, orthopedic and surgical methods of immobilization of bone fragments are used, which are used both in isolation and in various combinations. During surgical treatment with the help of mini-plates, it is possible to perform optimal reposition and stable fixation of fragments, however, the traumatic nature of the operation, leading to bone hypoxia, slows down the processes of reparative osteogenesis and leads to the development of postoperative complications. The use of bone glue-cement makes it possible to achieve reliable fixation of bone fragments, accelerate the formation of a callus. At the same time, there is no need to remove the glue, since it is a biodegradable material. Conclusions 1. None of the currently used methods of fixation of bone fragments in clinical practice for fractures of the mandible, both orthopedic and surgical, as well as in their combination, can fully meet the optimal conditions of reparative osteogenesis. 2. A promising alternative method is the use of bone adhesives that fill the bone voids between fragments, which contributes to their stable fixation and reparative osteogenesis, biodegrading simultaneously with the formation of a callus.

Integrin αVβ3 antagonist-c(RGDyk) peptide attenuates the progression of ossification of the posterior longitudinal ligament by inhibiting osteogenesis and angiogenesis

BackgroundOssification of the posterior longitudinal ligament (OPLL), an emerging heterotopic ossification disease, causes spinal cord compression, resulting in motor and sensory dysfunction. The etiology of OPLL remains unclear but may involve integrin αVβ3 regulating the process of osteogenesis and angiogenesis. In this study, we focused on the role of integrin αVβ3 in OPLL and explored the underlying mechanism by which the c(RGDyk) peptide acts as a potent and selective integrin αVβ3 inhibitor to inhibit osteogenesis and angiogenesis in OPLL.MethodsOPLL or control ligament samples were collected in surgery. For OPLL samples, RNA-sequencing results revealed activation of the integrin family, particularly integrin αVβ3. Integrin αVβ3 expression was detected by qPCR, Western blotting, and immunohistochemical analysis. Fluorescence microscopy was used to observe the targeted inhibition of integrin αVβ3 by the c(RGDyk) peptide on ligaments fibroblasts (LFs) derived from patients with OPLL and endothelial cells (ECs). The effect of c(RGDyk) peptide on the ossification of pathogenic LFs was detected using qPCR, Western blotting. Alkaline phosphatase staining or alizarin red staining were used to test the osteogenic capability. The effect of the c(RGDyk) peptide on angiogenesis was determined by EC migration and tube formation assays. The effects of the c(RGDyk) peptide on heterotopic bone formation were evaluated by micro-CT, histological, immunohistochemical, and immunofluorescence analysis in vivo.ResultsThe results indicated that after being treated with c(RGDyk), the osteogenic differentiation of LFs was significantly decreased. Moreover, the c(RGDyk) peptide inhibited the migration of ECs and thus prevented the nutritional support required for osteogenesis. Furthermore, the c(RGDyk) peptide inhibited ectopic bone formation in mice. Mechanistic analysis revealed that c(RGDyk) peptide could inhibit osteogenesis and angiogenesis in OPLL by targeting integrin αVβ3 and regulating the FAK/ERK pathway.ConclusionsTherefore, the integrin αVβ3 appears to be an emerging therapeutic target for OPLL, and the c(RGDyk) peptide has dual inhibitory effects that may be valuable for the new therapeutic strategy of OPLL.

Potential probiotic Lactobacillus delbrueckii subsp. lactis KUMS-Y33 suppresses adipogenesis and promotes osteogenesis in human adipose-derived mesenchymal stem cell

Today, probiotics are considered to be living microorganisms whose consumption has a certain number of beneficial effects on the consumer. The present study aimed to investigate the effect of a new probiotic extract (Lactobacillus delbrueckii subsp. lactis KUMS Y33) on the differentiation process of human adipose-derived stem cells (hADSCs) into adipocytes and osteocytes and, as a result, clarify its role in the prevention and treatment of bone age disease. Several bacteria were isolated from traditional yogurt. They were evaluated to characterize the probiotic’s activity. Then, the isolated hADSCs were treated with the probiotic extract, and then osteogenesis and adipogenesis were induced. To evaluate the differentiation process, oil red O and alizarin red staining, a triglyceride content assay, an alkaline phosphatase (ALP) activity assay, as well as real-time PCR and western blot analysis of osteocyte- and adipocyte-specific genes, were performed. Ultimately, the new strain was sequenced and registered on NBCI. In the probiotic-treated group, the triglyceride content and the gene expression and protein levels of C/EBP-α and PPAR-γ2 (adipocyte-specific markers) were significantly decreased compared to the control group (P < 0.05), indicating an inhibited adipogenesis process. Furthermore, the probiotic extract caused a significant increase in the ALP activity, the expression levels of RUNX2 and osteocalcin, and the protein levels of collagen I and FGF-23 (osteocyte-specific markers) in comparison to the control group (P < 0.05), indicating an enhanced osteogenesis process. According to the results of the present study, the probiotic extract inhibits adipogenesis and significantly increases osteogenesis, suggesting a positive role in the prevention and treatment of osteoporosis and opening a new aspect for future in-vivo study.

Pharmacological correction of experimentally induced osteoporosis complicated by type 2 diabetes mellitus

BACKGROUND: Osteoporosis remains one of the most important medical problems worldwide with significant economic consequences. The development of new drugs based on unique biologically active compounds can contribute significantly to osteoporosis management. AIM: To evaluate the osteogenesis processes by evaluating bone-remodeling markers in the blood serum during the treatment of experimental osteoporosis complicated by type 2 diabetes mellitus. MATERIALS AND METHODS: The study was performed on an experimental model of osteoporosis, followed by the induction of type 2 diabetes mellitus, using biochemical methods to analyze markers of osteoporosis in the blood serum. RESULTS: The results of the analysis of bone remodeling markers revealed that the antiosteoporotic activity of a composite preparation based on succinic acid salts is dependent on glucose metabolism disorders such as diabetes mellitus. The high efficacy of the new drug in monotherapy and combination with vitamin D3 in the activation of osteogenesis in experimental osteoporosis was balanced by impaired metabolic processes in type 2 diabetes mellitus. CONCLUSIONS: The results indicate the dependence of the pharmacological effectiveness of the antiosteoporosis agent on metabolic disorders, such as type 2 diabetes mellitus, in female rats with experimental osteoporosis.

CircPRKD3/miR-6783-3p responds to mechanical force to facilitate the osteogenesis of stretched periodontal ligament stem cells

BackgroundThe mechanotransduction mechanisms by which cells regulate tissue remodeling are not fully deciphered. Circular RNAs (circRNAs) are crucial to various physiological processes, including cell cycle, differentiation, and polarization. However, the effects of mechanical force on circRNAs and the role of circRNAs in the mechanobiology of differentiation and remodeling in stretched periodontal ligament stem cells (PDLSCs) remain unclear. This article aims to explore the osteogenic function of mechanically sensitive circular RNA protein kinase D3 (circPRKD3) and elucidate its underlying mechanotransduction mechanism.Materials and methodsPDLSCs were elongated with 8% stretch at 0.5 Hz for 24 h using the Flexcell® FX-6000™ Tension System. CircPRKD3 was knockdown or overexpressed with lentiviral constructs or plasmids. The downstream molecules of circPRKD3 were predicted by bioinformatics analysis. The osteogenic effect of related molecules was evaluated by quantitative real-time PCR (qRT‐PCR) and western blot.ResultsMechanical force enhanced the osteogenesis of PDLSCs and increased the expression of circPRKD3. Knockdown of circPRKD3 hindered PDLSCs from osteogenesis under mechanical force, while overexpression of circPRKD3 promoted the early osteogenesis process of PDLSCs. With bioinformatics analysis and multiple software predictions, we identified hsa-miR-6783-3p could act as the sponge of circPRKD3 to indirectly regulate osteogenic differentiation of mechanically stimulated PDLSCs.ConclusionsOur results first suggested that both circPRKD3 and hsa-miR-6783-3p could enhance osteogenesis of stretched PDLSCs. Furthermore, hsa-miR-6783-3p could sponge circPRKD3 to indirectly regulate RUNX2 during the periodontal tissue remodeling process in orthodontic treatment.

Chitosan modified with PAP as a promising delivery system for melatonin in the treatment of osteoporosis: targeting the divalent metal transporter 1.

The demands for novel and efficient therapies have gradually increased with the rising concerns of osteoporosis (OP). The most popular method in promoting bone regeneration during osteoporotic conditions consists of loading bioactive materials with different drugs to treat osteoporotic bones by either promoting the process of osteogenesis, or by inhibiting the activity of osteoclasts. By analyzing single cell sequencing results, we found that divalent metal transporter 1 (DMT1) played a role in OP. Based on our previous results, we found that melatonin (MT) suppressed expression of DMT1 induced by high glucose during OP, so we determined the efficacy of MT for the treatment of OP. However, the clinical effects of MT on OP were unsatisfactory. To enhance its biological efficacy, we combined MT with porous gelatin chitosan (chitosan) and the conductive material, PLA-b-AP-b-PLA (PAP), then determined how MT incorporation in chitosan@PAP nanoparticles affected the ability to promote MC3T3-E1 osteogenesis and mineralization, both in vitro and in vivo. The results confirmed the effect of MT on DMT1. We then prepared and characterized composites prepared as nanofibers, and determined the efficacy of MT combined with chitosan-PAP modified hydrogels as a slow-release system in a femur model of osteoporosis mice, with associated properties suitable for bone tissue engineering. The results indicated that MT-loaded chitosan@PAP nanospheres showed favorable osteogenic functions, both in vivo and in vitro, providing a practical solution for bone regeneration for OP patients.

Circ_0003764 Regulates the Osteogenic Differentiation of Periodontal Ligament Stem Cells

Specific circular RNAs (circRNAs) have been proven to play crucial roles in osteogenesis in vitro and in vivo. This study aims to identify a certain circRNA involved in the osteogenic differentiation of periodontal ligament stem cells (PDLSCs) and explore its regulatory role. The expression of 5 candidate circRNAs (circ_0026344, circ_ACAP2, circ_0003764, circ_0008259, and circ_0060731) was detected by real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR) after PDLSCs were cultured in the osteogenic induction medium or medium supplemented with tumour necrosis factor-α (TNF-α, 10 ng/mL) for 3 and 7 days. The circRNA significantly decreased in both 3 and 7 days of osteogenic induction in PDLSCs and markedly increased in TNF-α-induced PDLSCs for 3 and 7 days screened. Identified circRNA was knocked down or overexpressed, and the effect on the osteogenic differentiation of PDLSCs was investigated by qRT-PCR, western blot, alkaline phosphatase (ALP) staining, and alizarin red S (ARS) staining. Cell counting kit-8 (CCK-8) assay and 5-ethynyl-2'-deoxyuridine (EdU) assay were applied to detect the effect of the circRNA on the proliferation of PDLSCs. qRT-PCR results showed that the expression of circ_0003764 was significantly decreased when PDLSCs were cultured in the osteogenic induction medium for 3 or 7 days, whereas it was dramatically increased in TNF-α-induced PDLSCs. Knockdown of circ_0003764 promoted the expression of the osteogenesis-related genes (RUNX2, ALP, OCN) and proteins (RUNX2, OCN), enhanced the ALP activity, and elevated the mineralization by PDLSCs, as shown by ARS staining. However, with the overexpression of circ_0003764, the osteogenic differentiation capacity of PDLSCs was significantly reduced. The CCK-8 and EdU results indicated that circ_0003764 could inhibit the proliferation of PDLSCs. Circ_0003764 is involved in the osteogenesis process and inhibits the osteogenic differentiation and proliferation of PDLSCs. This study indicates that circ_0003764 can serve as a diagnostic and therapeutic target in bone regeneration-related diseases treated by PDLSCs-based tissue engineering.

Indirect co-culture of osteoblasts and endothelial cells in vitro based on a biomimetic 3D composite hydrogel scaffold to promote the proliferation and differentiation of osteoblasts.

The field of orthopedics has long struggled with the challenge of repairing and regenerating bone defects, which involves a complex process of osteogenesis requiring coordinated interactions among different types of cells. The crucial role of endothelial cells and osteoblasts in bone vascularization and osteogenesis underscores the importance of their intimate interaction. However, efforts to bioengineer bone tissue have been impeded by the difficulty in establishing proper angiogenesis and osteogenesis in tissue structures. This study presents a novel approach to bone tissue engineering, involving a three-dimensional composite hydrogel scaffold composed of sodium alginate microspheres encapsulated in type I collagen. Using this scaffold, a three-dimensional indirect co-culture system was established for osteoblasts and endothelial cells to evaluate the osteogenic differentiation potential of osteoblasts. Results demonstrate that the non-contact co-culture system of endothelial cells and osteoblasts constructed by the composite hydrogel scaffold loaded with microspheres holds promise for bone tissue engineering. The innovative concept of an indirect co-culture system presents exciting prospects for conducting intercellular communication studies and offers a valuable in vitro tissue platform to investigate tissue regeneration.