Increase in bone metabolic markers and circulating osteoblast-lineage cells after orthognathic surgery

Postoperative decrease in Hounsfield unit values at adjacent vertebrae after thoraco-pelvic fusion as a risk factor of proximal junctional kyphosis

Proximal junctional kyphosis and failure is a common complication of adult spinal deformity surgery, with osteoporosis as a risk factor. This retrospective study investigated the influence of long thoracolumbar fusion with pelvic fixation on regional bone density of adjacent vertebrae (Hounsfield units on computed tomography) and evaluated the association between bone loss and the incidence of proximal junctional kyphosis and failure. Patients who underwent long thoracolumbar fusion (pelvis to T10 or above) or single-level posterior lumbar interbody fusion (control group) between 2016 and 2022 were recruited. Routine computed tomography preoperatively and within 1-2 weeks postoperatively was performed. Postoperative changes in Hounsfield unit values in the vertebrae at one and two levels above the uppermost instrumented vertebrae (UIV + 1 and UIV + 2) were evaluated. Overall, 127 patients were recruited: 45 long fusion (age, 73.9 ± 5.6 years) and 82 proximal junctional kyphosis and failure (age, 72.5 ± 9.3 years). Postoperative computed tomography was performed at a median [interquartile range] of 3.0 [1.0-7.0] and 4.0 [1.0-7.0] days, respectively. In both groups, Hounsfield unit values at UIV + 2 were significantly decreased postoperatively. In the long-fusion group, Hounsfield unit values at UIV + 1 and UIV + 2 were significantly lower in patients with proximal junctional kyphosis and failure (within 18 months postoperatively) than in those without proximal junctional kyphosis and failure. Proximal junctional kyphosis and failure and long thoraco-pelvic fusion negatively affect regional Hounsfield unit values at adjacent levels immediately after surgery. Patients with subsequent proximal junctional kyphosis and failure show greater postoperative bone loss at adjacent levels than those without.

Diagnostic and Prognostic Value of Indicators of Bone Metabolism Markers in Patients Following Mandibulectomy and Free Fibula Flap Reconstruction with Endosteal Implants

Purpose

To evaluate and assess the indicators of bone metabolism markers osteocalcin and β-Cross-Laps in blood serum as a tool for monitoring bone regeneration and determining the time of implantation in patients after mandibulectomy and reconstruction of a free fibular flap with subsequent endosteal implants.

Materials and Methods

Forty-eight patients in a 6-year period participated in this study, due to resection for tumors. All patients underwent reconstruction with fibula free flap after tumor resection, 4-6 months after osteoectomy, dental implants were installed with further orthopedic rehabilitation. To assess the rate of bone remodeling after transplantation, the content biochemical markers of bone remodeling osteocalcin and β-Cross-Laps serum were determined by enzyme immunoassay.

Results

All 46 fibular free flaps were healed without complications and were survived. A total 326 implants installed, 8 implants failed to osseointegrate, and 6 implants failed after 5 years of loading (peri-implantitis). Success rate of implants after 5 years was 95,7%. In patients before surgery, the mean of osteocalcin levels was 8.5 ng/ml, two months later, there was a sharp increase in the content of osteocalcin by 15.4 ng/ml, after four months reached 24.7 ng/ml, after six months of 28.6 ng/ml, then the indicator began to decrease and after 12 months it was approaching the norm of 14.7 ng/ml. In patients before surgery, the mean level of β-Cross-Laps was 0.76 ng/ml, after two months bone transplantation the mean level of β-Cross-Laps decreased to - 0.65 ng/ml, after four months the indicator increased and reached of 0.98 ng/ml, after six months the indicator was - 1.56 ng/ml, then these indicators began to decrease and after 12 months, approaching normal values of - 0.87 ng/ml. There is a correlation between different concentrations of osteocalcin or β-Cross- Laps and the success rate of implants. Implants were shown to be unsuccessful low concentrations of osteocalcin and high concentrations of β-Cross-Laps in serum.

Conclusion

Studies have shown that the long-term survival and success rates of implants placed in the reconstructed areas may guarantee an excellent prognosis of implant-supported prostheses. Bone markers in blood serum osteocalcin and β-Cross-Laps can be used to evaluate the rate of bone remodeling, which allows you to determine the time of implantation.

Surgery-first in interdisciplinary class II cases

OBJECTIVES

To present an interdisciplinary case treated with a surgery-first orthognathic approach, followed by orthodontic and prosthodontic treatment.

CLINICAL CONSIDERATIONS

After an accurate pre-operative virtual planning, a young patient with skeletal class II, retrognathia, and an anterior open bite was treated with bimaxillary orthognathic surgery without pre-surgical orthodontic decompensation. Orthodontic treatment was carried out post-operatively. The treatment was completed with a prosthodontic phase to improve the final esthetic outcome of the smile.

CONCLUSIONS

A surgery-first approach allowed to achieve esthetic and functional results in a reduced treatment duration that remained stable over the course of 1 year. The outcomes were consistent with prior research in terms of advantages brought by following an accurately planned surgery-first protocol. Nevertheless, longer-term follow-up was required to evaluate the treatment stability.

CLINICAL SIGNIFICANCE

An accurately planned surgery-first approach significantly helped in shortening the duration of the treatment, while providing a stable, functional, and esthetic solution to the patient's problems.

Protective effect of Pterospermum rubiginosum bark extract on bone mineral density and bone remodelling in estrogen deficient ovariectomized Sprague-Dawley (SD) rats

Osteoporosis is a common metabolic old age disorder characterised by low bone mass content (BMC) and mineral density (BMD) with micro-architectural deterioration of the extracellular matrix, further increasing bone fragility risk. Several traditional remedies, including plant extracts and herbal formulations, are used worldwide by local healers to improve the overall bone health and metabolism as an excellent osteoregenerative agent. Pteropsermum rubiginosum is an underexplored medicinal plant used by tribal peoples of Western Ghats, India, to treat bone fractures and associated inflammation. The proposed study evaluates the elemental profiling and phytochemical characterisation of P. rubiginosum methanolic bark extract (PRME), along with detailed In vitro and In vivo biological investigation in MG-63 cells and Sprague-Dawley (SD) rats. AAS and ICP-MS analysis showed the presence of calcium, phosphorus, and magnesium and exceptional levels of strontium, chromium, and zinc in PRME. The NMR characterisation revealed the presence of vanillic acid, Ergost-4-ene-3-one and catechin. The molecular docking studies revealed the target pockets of isolated compounds and various marker proteins in the bone remodelling cycle. In vitro studies showed a significant hike in ALP and calcium content, along with upregulated mRNA expression of the ALP and COL1, which confirmed the osteoinductive activity of PRME in human osteoblast-like MG-63 cells. The in vivo evaluation in ovariectomised (OVX) rats showed remarkable recovery in ALP, collagen and osteocalcin protein after 3 months of PRME treatment. DEXA scanning reports in OVX rats supported the above in vitro and in vivo results, significantly enhancing the BMD and BMC. The results suggest that PRME can induce osteogenic activity and enhance bone formation with an excellent osteoprotective effect against bone loss in OVX animals due to estrogen deficiency.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-024-03942-7.

Optimization by mixture design of chitosan/multi-phase calcium phosphate/BMP-2 biomimetic scaffolds for bone tissue engineering

The modulation of cell behavior during culture is one of the most important aspects of bone tissue engineering because of the necessity for a complex mechanical and biochemical environment. This study aimed to improve the physicochemical properties of chitosan/multi-phase calcium phosphate (MCaP) scaffolds using an optimized mixture design experiment and evaluate the effect of biofunctionalization of the obtained scaffolds with the bone morphogenetic protein BMP-2 on stem cell behavior. The present study evaluated the compressive strength, elastic modulus, porosity, pore diameter, and degradation in simulated body fluids and integrated these responses using desirability. The properties of the scaffolds with the best desirability (18.4% of MCaP) were: compressive strength of 23 kPa, elastic modulus of 430 kPa, pore diameter of 163 μm, porosity of 92%, and degradation of 20% after 21 days. Proliferation and differentiation experiments were conducted using dental pulp stem cells after grafting BMP-2 onto scaffolds via the carbodiimide route. These experiments showed that MCaP promoted cell proliferation and increased alkaline phosphatase activity, whereas BMP-2 enhanced cell differentiation. This study demonstrates that optimizing the composition of a mixture of chitosan and MCaP improves the physicochemical and biological properties of scaffolds, indicating that this solution is viable for application in bone tissue engineering.

Osteoblast Biospecific Extraction Conjugated with HPLC Analysis for Screening Bone Regeneration Active Components from Moutan Cortex

INTRODUCTION

The function of promoting bone regeneration of Moutan Cortex (MC), a traditional Chinese medicine, has been widely known but, the effective components of MC in promoting osteoblast-mediated bone regeneration were still unclear.

OBJECTIVE

The method of osteoblast membrane bio-specific extraction conjugated with HPLC analysis was established to screen bone regeneration active components from MC.

METHODS

The fingerprints, washing eluate and desorption eluate of MC extract were analyzed by the established HPLC-DAD method. The established MC3T3-E1 cells membrane chromatography method was used for the bio-specific extraction of MC. The isolated compounds were identified by MS spectrometry. The effects and possible mechanisms of the isolated compounds were evaluated by molecular docking, ALP activity, cell viability by MTT Assay and proteins expression by Western Blot Analysis.

RESULTS

The active compound responsible for bone regeneration from MC was isolated using the established method of osteoblast membrane bio-specific extraction conjugated with HPLC analysis, and it was identified as 1,2,3,4,6-penta-O-β-galloyl-D-glucose (PGG) by MS spectrometry. It was further demonstrated through molecular docking that PGG could fit well into the functional ALP, BMP2, and Samd1 binding pocket. The proliferation of osteoblasts was promoted, the level of ALP was increased, and the protein expression of BMP2 and Smad1 was increased as shown by further pharmacological verification.

CONCLUSION

It was concluded that PGG, the bone regeneration active compound from MC, could stimulate the proliferation of osteoblasts to promote osteoblast differentiation, and its mechanism might be related to the BMP/Smad1 pathway.

Allosteric Activation of Transglutaminase 2 via Inducing an "Open" Conformation for Osteoblast Differentiation

Osteoblasts play an important role in the regulation of bone homeostasis throughout life. Thus, the damage of osteoblasts can lead to serious skeletal diseases, highlighting the urgent need for novel pharmacological targets. This study introduces chemical genetics strategy by using small molecule forskolin (FSK) as a probe to explore the druggable targets for osteoporosis. Here, this work reveals that transglutaminase 2 (TGM2) served as a major cellular target of FSK to obviously induce osteoblast differentiation. Then, this work identifies a previously undisclosed allosteric site in the catalytic core of TGM2. In particular, FSK formed multiple hydrogen bonds in a saddle-like domain to induce an "open" conformation of the β-sandwich domain in TGM2, thereby promoting the substrate protein crosslinks by incorporating polyamine. Furthermore, this work finds that TGM2 interacted with several mitochondrial homeostasis-associated proteins to improve mitochondrial dynamics and ATP production for osteoblast differentiation. Finally, this work observes that FSK effectively ameliorated osteoporosis in the ovariectomy mice model. Taken together, these findings show a previously undescribed pharmacological allosteric site on TGM2 for osteoporosis treatment, and also provide an available chemical tool for interrogating TGM2 biology and developing bone anabolic agent.

Three-dimensional evaluation of postoperative stability: a comparative study between surgery-first and surgery-late protocols

The main objective of this study was to compare the stability of the surgery-first and surgery-late approaches according to the standardized centre protocols, by three-dimensional evaluation after 1 year of follow-up. A retrospective study was designed that included a test group (surgery-first protocol) and a control group (surgery-late protocol), with a follow-up period of at least 1 year (average 14 months; range 12-24 months). Stability was evaluated using linear and angular measurements by superimposing cone beam computed tomography images obtained at specific points in time: preoperatively, 1 month after surgery, and at the end of the orthodontic treatment. A total of 56 patients with a mean age of 32.2 ± 11.1 years were included in the study. After surgery there were significant changes in all of the measurements in at least one dimension in both groups (except for the transverse maxillary dimension), which remained stable at the end of the treatment, with no statistically significant differences between the two groups. At the 1-year follow-up, both groups presented a SNA angle relapse; this relapse was more significant in the surgery-late group (P = 0.031) and was present only in Class III patients (P = 0.013). In conclusion, an equivalent three-dimensional stability between surgery-first and surgery-late protocols was demonstrated after 1 year of follow-up when eligibility criteria were strictly adhered to.

NiFe2O4/ZnO-coated Poly(L-Lactide) nanofibrous scaffold enhances osteogenic differentiation of human mesenchymal stem cells

Background: A combination of bioceramics and polymeric materials has attracted the research community’s interest in bone tissue engineering. These composites are essential to support cell attachment, proliferation, and osteogenesis differentiation, which are vital as a classic strategy in bone tissue engineering. In this study, NiFe2O4/ZnO-coated poly L-Lactide (PLLA) was employed as a scaffold to evaluate the osteogenic differentiation capability of human adipose tissue derived mesenchymal stem cells (hAMSCs).

Material and methods: The electrospun PLLA nanofibers were fabricated, coated with nanocomposite (NiFe2O4/ZnO), and evaluated by the water contact angle (WCA), tensile test, attenuated total reflectance fourier-transform infrared (ATR-FTIR) and scanning electron microscopy (SEM). Then, the osteogenic differentiation potential of hAMSCs was assessed using NiFe2O4/ZnO-coated PLLA compared to tissue culture plastic (TCP) and a simple scaffold (PLLA) in vitro conditions.

Results: The adhesion, proliferation, and differentiation of hAMSCs were supported by the mechanical and biological properties of the NiFe2O4/ZnO-coated PLLA scaffold, according to SEM and 4′,6-Diamidino-2-phenylindole dihydrochloride (DAPI) staining patterns. During bone differentiation, Alkaline phosphatase (ALP) enzyme activity, biomineralization, calcium content, and osteogenic gene expression (ALP, Osteonectin, Osteocalcin, Collagen type I, and Runx2) were higher on NiFe2O4/ZnO-coated PLLA scaffold than on PLLA scaffold and TCP.

Conclusion: Based on our results, the osteogenic differentiation of hAMSCs on the improved biological scaffold (PLLA coated with NiFe2O4/ZnO) could accelerate due to the stimulating effect of this nanocomposite.

A Biofabrication Strategy for a Custom-Shaped, Non-Synthetic Bone Graft Precursor with a Prevascularized Tissue Shell

Critical-sized defects of irregular bones requiring bone grafting, such as in craniofacial reconstruction, are particularly challenging to repair. With bone-grafting procedures growing in number annually, there is a reciprocal growing interest in bone graft substitutes to meet the demand. Autogenous osteo(myo)cutaneous grafts harvested from a secondary surgical site are the gold standard for reconstruction but are associated with donor-site morbidity and are in limited supply. We developed a bone graft strategy for irregular bone-involved reconstruction that is customizable to defect geometry and patient anatomy, is free of synthetic materials, is cellularized, and has an outer pre-vascularized tissue layer to enhance engraftment and promote osteogenesis. The graft, comprised of bioprinted human-derived demineralized bone matrix blended with native matrix proteins containing human mesenchymal stromal cells and encased in a simple tissue shell containing isolated, human adipose microvessels, ossifies when implanted in rats. Ossification follows robust vascularization within and around the graft, including the formation of a vascular leash, and develops mechanical strength. These results demonstrate an early feasibility animal study of a biofabrication strategy to manufacture a 3D printed patient-matched, osteoconductive, tissue-banked, bone graft without synthetic materials for use in craniofacial reconstruction. The bone fabrication workflow is designed to be performed within the hospital near the Point of Care.

Inhibition of miRNA-100 facilitates bone regeneration defects of mesenchymal stem cells in osteoporotic mice through the protein kinase B pathway

Osteoporotic patients suffer from bone microstructure damage and are prone to fracture and bone defect. Due to the damage of bone healing ability, the bone repair of osteoporotic patients is usually slow. Here we aimed to explore the function and potential molecular mechanism of miR-100 in osteogenic differentiation ability of bone marrow stem cells (BMSCs). Ovariectomy was performed on mice to induce osteoporosis. BMSCs were extracted from normal and ovariectomized (OVX) mice to examine the effect of microRNA (miR)-100 on BMSC osteogenic differentiation. Hematoxylin and eosin (H&E) staining and safranin O-fast green staining assays were performed on femur tissues to reveal pathological changes. The osteogenic differentiation of BMSCs were determined by Alkaline Phosphatase and Alizarin red staining assays. The results showed that miR-100 expression was significantly upregulated in bone tissues and BMSCs from osteoporotic mice. MiR-100 knockdown partially improved osteogenic function of OVX mice-derived BMSCs. Next, mechanistic target of rapamycin kinase (MTOR) was identified as the target downstream miR-100. MiR-100 deficiency can activate the protein kinase B (AKT)/mTOR pathway. MiR-100 controlled the osteogenic function of BMSCs by the AKT/mTOR pathway. Collectively, our findings demonstrate that inhibition of miR-100 facilitates bone regeneration defects of BMSCs in osteoporotic mice through AKT pathway, indicating that miR-100 might be an effective target for the treatment of osteoporotic mandibular injury and bone defect diseases.

Large-pore-size Ti6Al4V scaffolds with different pore structures for vascularized bone regeneration

Porous Ti6Al4V scaffolds are characterized by high porosity, low elastic modulus, and good osteogenesis and vascularization, which are expected to facilitate the repair of large-scale bone defects in future clinical applications. Ti6Al4V scaffolds are divided into regular and irregular structures according to the pore structure, but the pore structure more capable of promoting bone regeneration and angiogenesis has not yet been reported. The purpose of this study was to explore the optimal pore structure and pore size of the Ti6Al4V porous scaffold for the repair of large-area bone defects and the promotion of vascularization in the early stage of osteogenesis. 7 groups of porous Ti6Al4V scaffolds, named NP, R8, R9, R10, P8, P9 and P10, were fabricated by Electron-beam-melting (EBM). Live/dead staining, immunofluorescence staining, SEM, CCK8, ALP, and PCR were used to detect the adhesion, proliferation, and differentiation of BMSCs on different groups of scaffolds. Hematoxylin-eosin (HE) staining and Van Gieson (VG) staining were used to detect bone regeneration and angiogenesis in vivo. The research results showed that as the pore size of the scaffold increased, the surface area and volume of the scaffold gradually decreased, and cell proliferation ability and cell viability gradually increased. The ability of cells to vascularize on scaffolds with irregular pore sizes was stronger than that on scaffolds with regular pore sizes. Micro-CT 3D reconstruction images showed that bone regeneration was obvious and new blood vessels were thick on the P10 scaffold. HE and VG staining showed that the proportion of bone area on the scaffolds with irregular pores was higher than that on scaffolds with regular pores. P10 had better mechanical properties and were more conducive to bone tissue ingrowth and blood vessel formation, thereby facilitating the repair of large-area bone defects.

Polygalacto-fucopyranose biopolymer structured nanoparticle conjugate attenuates glucocorticoid-induced osteoporosis: An in vivo study

Naturally occurring polysaccharide-structured nanoparticles have developed as promising materials for treatment of bone health disorders. Silver nanoparticle (ST-AgNP) structured from sulfated polygalacto-fucopyranose comprising of recurring structural entities of 2-SO3-α-(1 → 3)-fucopyranose and 6-O-acetyl-β-(1 → 4)-galactopyranose isolated from marine macroalga Sargassum tenerrimum demonstrated potential activities associated with osteogenesis. Subsequent treatment with ST-AgNP, activity of alkaline phosphatase (63 mU/mg) was raised in osteoblast stem cells (human mesenchymal, hMSC) than that in control (30 mU/mg). Intense growth of mineralized nodule on the surface of hMSC was apparent following treatment with ST-AgNP. Increased population of bone morphogenic protein-2 (23%) and osteocalcin+ cells (50%) on M2 macrophages were apparent following treatment with ST-AgNP (0.25 mg/mL). Glucocorticoid-induced in vivo animal model studies of ST-AgNP exhibited significant recovery of serum biochemical parameters along with serum estradiol and parathyroid hormone compared to disease control. Disease-induced groups treated with ST-AgNP showed the disappearance of osteoporotic cavities in the trabecular bone. Following treatment with ST-AgNP, serum calcium and phosphorus contents were significantly recovered.

Marine Macroalgal Polygalactan-Built Nanoparticle Construct for Osteogenesis

Naturally derived polysaccharide biopolymer-based nanoparticles with their size and drug release potentials have appeared as promising biomaterials for osteogenic differentiation. A metallic nanoparticle (GS-AgNP) prepared from a sulfated polygalactan characterized as →3)-2-O-methyl-O-6-sulfonato-β-d-galactopyranosyl-(1 → 4)-2-O-methyl-3,6-anhydro-α-d-galactopyranose-(1→ isolated from the marine macroalga Gracilaria salicornia exhibited a prospective osteogenic effect. Upon treatment with the studied GS-AgNP, alkaline phosphatase activity (88.9 mU/mg) was significantly elevated in human mesenchymal osteoblast stem cells (hMSCs) compared to that in the normal control (33.7 mU/mg). A mineralization study of GS-AgNPs demonstrated an intense mineralized nodule formation on the hMSC surface. A fluorescence-activated cell sorting study of osteocalcin and bone morphogenic protein-2 (BMP-2) expression resulted in an increased population of osteocalcin (78.64%) and BMP-2-positive cells (46.10%) after treatment with GS-AgNPs (250 μg/mL) on M2 macrophages. A time-dependent cell viability study of GS-AgNPs exhibited its non-cytotoxic nature. The studied polygalactan-built nanoparticle could be developed as a promising bioactive pharmacophore against metabolic bone disorder and the treatment for osteogenesis therapy.

Identification of key interactions between SARS-CoV-2 main protease and inhibitor drug candidates

The number of cases of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection (COVID-19) has reached over 114,000. SARS-CoV-2 caused a pandemic in Wuhan, China, in December 2019 and is rapidly spreading globally. It has been reported that peptide-like anti-HIV-1 drugs are effective against SARS-CoV Main protease (Mpro). Due to the close phylogenetic relationship between SARS-CoV and SARS-CoV-2, their main proteases share many structural and functional features. Thus, these drugs are also regarded as potential drug candidates targeting SARS-CoV-2 Mpro. However, the mechanism of action of SARS-CoV-2 Mpro at the atomic-level is unknown. In the present study, we revealed key interactions between SARS-CoV-2 Mpro and three drug candidates by performing pharmacophore modeling and 1 μs molecular dynamics (MD) simulations. His41, Gly143, and Glu166 formed interactions with the functional groups that were common among peptide-like inhibitors in all MD simulations. These interactions are important targets for potential drugs against SARS-CoV-2 Mpro.

Assessment and Comparison of the Efficacy of Methotrexate, Prednisolone, Adalimumab, and Tocilizumab on Multipotency of Mesenchymal Stem Cells

Mesenchymal stem cell (MSC)-based articular regeneration might be beneficial for both protecting and rebuilding cartilaginous tissues in the management of rheumatoid arthritis. However, it is unclear how current immunosuppressive strategies influence the multipotency of MSCs. The present study was undertaken to profile the direct effectiveness of major antirheumatic drugs including methotrexate, prednisolone, adalimumab, and tocilizumab on the multipotency of MSCs, with a special focus on chondrogenesis. The inhibitory effects of methotrexate on adipogenesis, osteogenesis, and chondrogenesis were observed to occur in a dose-dependent manner in an in vitro differentiation system. Prednisolone enhanced adipogenesis, but reduced alkaline phosphatase activity in osteoprogenitors and suppressed the formation of chondrospheroids. Adalimumab suppressed alkaline phosphatase activity, while tocilizumab diminished osteogenesis and chondrogenesis of MSCs in vitro. Chondrogenesis of antirheumatic drug-treated MSCs was also evaluated in vivo using a scaffolded spheroid-engrafted murine model. The biologics examined appeared to be relatively safe for cartilaginous formation, but methotrexate and prednisolone exhibited opposing influences on chondrogenesis. Taken together, these results reveal the direct efficacy of major antirheumatic agents on the multipotency of MSCs. Therefore, our findings suggest that optimization of medication protocols is further required for therapeutic approaches involving cartilaginous tissue engineering.