Mineralized Bone Tissue Research Articles

Diagnostic possibilities of determination of osteogenesis disorders in children born with low body weight

Diagnostic possibilities of determination of osteogenesis disorders in children born with low body weight

Utilização do Piezoeletricidade na odontologia: Revisão de literatura


 Introdução: A piezoeletricidade surgiu em meados do século XIX, o piezo ultrassônico consiste na utilização de um aparelho ultrassônico, capaz de cortar tecido ósseo mineralizado, sem lesionar o tecido mole sendo essa uma de suas principais vantagens quando comparado às técnicas convencionais com brocas, serras e instrumentais.
 
 
 Objetivo: Este estudo tem como objetivo, realizar uma revisão de literatura acerca das diversas utilizações do piezoeletricidade na odontologia.
 
 
 Materiais e Metódos: Para a elaboração desse artigo foi realizada uma revisão narrativa da literatura, utilizando as bases de dados: PUBMED/ MEDLINE, Google acadêmico, Scielo, Revodonto, LILACS, BBO e Portal CAPES. Foram selecionados artigos que abordassem os assuntos cirurgia com ultrassom, piezocirúrgico, técnicas cirúrgicas alternativas e aparelhos cirúrgicos de vibração.
 
 
 Discussão: De acordo com a teoria dos irmãos Curie o efeito piezoelétrico acontece através do uso de tipos específicos de cerâmicas e cristais como o quartzo, os quais sofrem deformações quando uma corrente elétrica passa através deles, resultando em oscilações de frequência ultrassônica e quando aplica-se sobre uma superfície estas vibrações mecânicas geram uma ruptura na coesão molecular provocam cavitações nesta superfície.
 
 
 Conclusão: O piezocirúrgico ultrassônico demonstra ser um dispositivo seguro e eficaz para a realização de procedimentos cirúrgicos na odontologia, devido a proteção aos tecidos moles, melhor hemostasia, diminuição do ruído e vibração, diminuição do estresse e medo do paciente, minimização de dano a estruturas nobres como feixes vásculo nervoso.

Determinants of bone health in adults Polish women: The influence of physical activity, nutrition, sun exposure and biological factors

PurposeThe aim of this study was to assess the determinants of bone health in the group of women over 40 years old. Lifestyle factors such as past and present physical activity, past and present sun exposure, current dietary intake of calcium and vitamin D, nutritional status as measured by BMI, family history of osteoporosis and current hormonal status were analysed.MethodsThe study involved 500 women over 40 years old. All examined women was the same ethnicity- European origin. Methods used: densitometry method (DXA), bioelectrical impedance analysis, International Physical Activity Questionnaire, nutrition questionnaire, past and present sun exposure questionnaire. Past and present physical activity, past and present sun exposure and sufficient level of calcium in the diet proved to be the most important factors determining mineralization of bone tissue of women. In order to indicate an independent association of the correct bone tissue mineralization with individual factors, multivariate analysis was used—logistic regression.ResultsThe norm BMD in the distal part of the forearm was strongly influenced: recommended dietary calcium intake (OR = 5.95; p = 0.003), moderately (OR = 1.88; p = 0.053) and high (OR = 14.0; p<0.001) past physical activity, sufficient (OR = 4.97; p<0.001) and high (OR = 18.9; p = 0.004) level of present physical activity, sufficient past (OR = 5.15; p<0.001) and sufficient present sun exposure (OR = 10.0; p<0.001).The chance for the BMD prox norm was also increased several times: high past physical activity (OR = 68.4; p<0.0001) and sufficient past sun exposure (OR = 10.6; p<0.001), moderate past activity (OR = 4.20; p<0.001), sufficient (OR = 6.13; p<0.001) and high (OR = 10.0; p<0.001) present physical activity, sufficient present sun exposure (OR = 9.09; p<0.0001), recommended intake of calcium (OR = 9.57; p<0.001) and vitamin D (OR = 2.68; p = 0.052). Whereas e significantly lower likelihood for the BMD prox norm was found in women with the oldest hormonal status (postmenopausal period) (OR = 0.18; p<0.001), with osteoporosis in the family (OR = 0.37; p<0.001) and living in an agglomeration (OR = 0.68; p = 0.03).ConclusionInterventions to increase physical activity, especially outdoors, may help reduce risk of osteoporosis, fractures and subsequent healthcare costs.

A Multifunctional Antibacterial and Osteogenic Nanomedicine: QAS-Modified Core-Shell Mesoporous Silica Containing Ag Nanoparticles.

Treatments for infectious bone defects such as periodontitis require antibacterial and osteogenic differentiation capabilities. Nanotechnology has prompted the development of multifunctional material. In this research, we aim to synthesize a nanoparticle that can eliminate periodontal pathogenic microorganisms and simultaneously stimulate new bone tissue regeneration and mineralization. QAS-modified core-shell mesoporous silica containing Ag nanoparticles (Ag@QHMS) was successfully synthesized through the classic hydrothermal method and surface quaternary ammonium salt functionalization. The Ag@QHMS in vitro antibacterial activity was explored via coculture with Staphylococcus aureus, Escherichia coli, and Porphyromonas gingivalis biofilms. Bone mesenchymal stem cells (BMSCs) were selected for observing cytotoxicity, apoptosis, and osteogenic differentiation. Ag@QHMS showed a good sustained release profile of Ag+ and a QAS-grafted mesoporous structure. Compared with the single-contact antibacterial activity of QHMS, Ag@QHMS exhibited a more efficient and stable concentration-dependent antimicrobial efficacy; the minimum inhibitory concentration was within 100 μg/ml, which was below the BMSC biocompatibility concentration (200 μg/ml). Thus, apoptosis would not occur while promoting the increased expression of osteogenic-associated factors, such as runt-related transcription factor 2 (RUNX2), alkaline phosphatase (ALP), osteopontin (OPN), osteocalcin (OCN), bone sialoprotein (BSP), and collagen type 1 (COL-1). A safe concentration of particles can stimulate cell alkaline phosphatase and matrix calcium salt deposition. The dual antibacterial effect from the direct contact killing of QAS and the sustained release of Ag nanoparticles, along with the Ag-promoted osteogenic differentiation, had been verified and utilized in Ag@QHMS. This system demonstrates the potential for utilizing pluripotent biomaterials to treat complex lesions.

Canagliflozin, an SGLT2 inhibitor, corrects glycemic dysregulation in TallyHO model of T2D but only partially prevents bone deficits.

Higher fracture risk in type 2 diabetes (T2D) is attributed to disease-specific deficits in micro-structural and material properties of bone, although the primary cause is not yet established. The TallyHO (TH) mouse is a polygenic model of early-onset T2D and obesity analogous to adolescent-onset T2D in humans. Due to incomplete penetrance of the phenotype, ~25% of male TH mice never develop hyperglycemia, providing a strain-matched, non-diabetic control. Utilizing this model of T2D, we examined the impact of glucose-lowering therapy with canagliflozin (CANA) on diabetic bone. Male TH mice with or without hyperglycemia (High BG, Low BG) were monitored from ~8 to 20weeks of age, and compared to age-matched, male, TH mice treated with CANA from ~8 to 20weeks of age. At 20weeks, untreated TH mice with high BG [High BG: 687±106mg/dL] exhibited lower body mass, decrements in cortical bone of the femur (decreased cross-sectional area and thickness; increased porosity) and in trabecular bone of the femur metaphysis and L6 vertebra (decreased bone volume fraction, thickness, and tissue mineral density), as well as decrements in cortical and vertebral bone strength (decreased yield force and ultimate force) when compared to untreated TH mice with low BG [Low BG: 290±98mg/dL; p<0.0001]. CANA treatment was metabolically advantageous, normalizing body mass, BG and HbA1c to values comparable to the Low BG group. With drug-induced glycemic improvement, cortical area and thickness were significantly higher in the CANA than in the High BG group, but deficits in strength persisted with lower yield force and yield stress (partially independent of bone geometry) in the CANA group. Additionally, CANA only partially prevented the T2D-related loss in trabecular bone volume fraction. Taken together, these findings suggest that the ability of CANA to lower glucose and normalized glycemic control ameliorates diabetic bone disease but not fully.

Calcium repletion to rats with calcipenic rickets fails to recover bone quality: A calcipenic “memory”

Calcipenic rickets is prevalent in underprivileged children in developing countries. Calcipenic rickets resulting from dietary calcium (Ca) deficiency decreases bone mass and deteriorates bone microstructure in humans. The effect of dietary Ca replenishment (CaR) on rachitic bones in animal models depends on the amount, critical period and duration of replenishment, however, the extent of recovery in various bone parameters including bone quality remains unclear. We investigated the effect of CaR in rat skeleton after inducing calcipenic rickets. Female SD rats (postnatal 28days/P28) were rendered calcipenic by feeding calcium deficient (CaD) diet (0.1% Ca) till P70 while control SD rats were fed Ca sufficient diet (0.8% Ca). At P70, calcipenic rats were switched to 0.8% Ca diet till P150 for one group and P210 for another group (endpoint). The CaD groups received 0.1% Ca diet throughout the study (P210). In the CaD groups, serum Ca and phosphate, and bone mineral density (BMD) were significantly decreased whereas serum alkaline phosphatase (ALP), iPTH and CTX-1 were increased compared to age-matched controls. Moreover, at the endpoint, the CaD group had reduced bone mass, surface referent bone formation parameters, tissue mineralization and strength accompanied by the increased osteoid thickness and microarchitectural decay (measured by trabecular geometric parameters) with poor crystal packing. The CaR group showed complete recovery in serum Ca, iPTH, ALP and CTX-1, and BMD, however, the bone quality parameters including bone strength, microarchitectural decay, tissue mineralization, and crystallinity were incompletely restored. Decreased surface referent bone formation and increased unmineralized bones (osteoid) indicative of osteomalacia were also observed in the CaR group at P210 compared with control despite prolonged replenishment. We conclude that a prolonged Ca repletion following the induction of calcipenic rickets in rats although shows the recovery of biochemical measures of bone metabolism and bone mass, however, the bone quality remains compromised. This suggests that a "memory" of calcipenia occurring at the early growth stage persists in the skeleton of adult rats despite a prolonged Ca replenishment.

Osseointegration of Titanium and Steel Additive Manufactured Implant in Rabbit Tibia under External Fixation: Comparative Study

Relevance. The main goals of successful prosthesis remain ensuring the osseointegration and infectious safety of implants.The purpose of the study — the comparative analysis of osseointegration of titanium and steel additive manufactured implants in the rabbit tibia under additional fixation by Ilizarov apparatus.Materials and Methods. The study was performed on 20 chinchilla male rabbits. The animals of the first group (n = 8 ) were implanted a stainless steel product EOS PH1 (EOS, Germany), the animals of the second group (n = 12) — a titanium alloy Ti6Al4V product. The implant was additionally fixed by Ilizarov apparatus. The implants were processed with additive technology by selective laser fusion at the EOSINT M 280 installation (EOS, Germany). The survival and safety of the implants were assessed using clinical, histological, laboratory and statistical methods.Results. The implant fall due to chronic inflammation was found in 2 animals of group 1 and none in group 2. The formation of weakly mineralized bone tissue on the surface of the implant was noted in 3 weeks in all cases. The bone became more mineralized by the 12th week of the experiment. However, in group 2, the calcium content and Ca / P ratio of the newly formed bone tissue at the 3rd and 12th week after implantation were significantly higher than in the animals of group 1. This indicated the greater maturity of the bone tissue in animals of group 2 at all stages of the experiment. In group 1, the compact plate osteoporosis and calcium-phosphorus balance disturbance were greater.Conclusion. The results of the study indicate that the survival rate (osseointegration) and safety of the product made of the titanium alloy were higher compared with the stainless steel product.

In vivo Regeneration of Mineralized Bone Tissue in Anisotropic Biomimetic Sponges

In the last two decades, alginate scaffolds have been variously studied as extracellular matrix analogs for tissue engineering. However, relevant evidence is still lacking concerning their ability to mimic the microenvironment of hierarchical tissues such as bone. Hence, an increasing amount of attention has recently been devoted to the fabrication of macro/microporous sponges with pore anisotropy able to more accurately replicate the cell niche structure as a trigger for bioactive functionalities. This paper presents an in vivo study of alginate sponges with anisotropic microporous domains (MAS) formed by ionic crosslinking in the presence of different fractions (30 or 50% v) of hydroxyapatite (HA). In comparison with unloaded sponges (MAS0), we demonstrated that HA confers peculiar physical and biological properties to the sponge, depending upon the inorganic fraction used, enabling the sponge to bio-mimetically support the regeneration of newly formed bone. Scanning electron microscopy analysis showed a preferential orientation of pores, ascribable to the physical constraints exerted by HA particles during the pore network formation. Energy dispersive spectroscopy (EDS) and X-Ray diffraction (XRD) confirmed a chemical affinity of HA with the native mineral phase of the bone. In vitro studies via WST-1 assay showed good adhesion and proliferation of human Dental Pulp-Mesenchymal Stem Cells (hDP-MSC) that increased in the presence of the bioactive HA signals. Moreover, in vivo studies via micro-CT and histological analyses of a bone model (e.g., a rat calvaria defect) confirmed that the maximum osteogenic response after 90 days was achieved with MAS30, which supported good regeneration of the calvaria defect without any evidence of inflammatory reaction. Hence, all of the results suggested that MAS is a promising scaffold for supporting the regeneration of hard tissues in different body compartments.

Sequenced Somatic Cell Reprogramming and Differentiation Inside Nested Hydrogel Droplets.

The efficient genesis of pluripotent cells or therapeutic cells for regenerative medicine involves several external manipulations and conditioning protocols, which drives down clinical applicability. Automated programming of the genesis by microscale physical forces and chronological biochemistry can increase clinical success. The design and fabrication of nested polysaccharide droplets (millimeter-sized) with cell sustaining properties of natural tissues and intrinsic properties for time and space evolution of cell transformation signals between somatic cells, pluripotent cells and differentiated therapeutic cells in a swift and efficient manner without the need for laborious external manipulation are reported. Cells transform between phenotypic states by having single and double nested droplets constituted with extracellular matrix proteins and reprogramming, and differentiation factors infused chronologically across the droplet space. The cell transformation into germ layer cells and bone cells is successfully tested in vitro and in vivo and promotes the formation of new bone tissues. Thus, nested droplets with BMP-2 loaded guests synthesize mineralized bone tissue plates along the length of a cranial non-union bone defect at 4 weeks. The advantages of sequenced somatic cell reprogramming and differentiation inside an individual hydrogel module without external manipulation, promoted by formulating tissue mimetic physical, mechanical, and chemical microenvironments are shown.

Bioactive PLGA/tricalcium phosphate scaffolds incorporating phytomolecule icaritin developed for calvarial defect repair in rat model.

Background/objectivesFor treatment of large bone defects challenging in orthopaedic clinics, bone graft substitutes are commonly used for the majority of surgeons. It would be proposed in the current study that our bioactive scaffolds could additionally serve as a local delivery system for therapeutic small molecule agents capable of providing support to enhance biological bone repair.MethodsIn this study, composite scaffolds made of poly (lactic-co-glycolic acid) (PLGA) and tricalcium phosphate (TCP) named by P/T was fabricated by a low-temperature rapid prototyping technique. For optimizing the scaffolds, the phytomolecule icaritin (ICT) was incorporated into P/T scaffolds called P/T/ICT. The osteogenic efficacies of the two groups of scaffolds were compared in a successfully established calvarial defect model in rats. Bone regeneration was evaluated by X-ray, micro-computerised tomography (micro-CT), and histology at weeks 4 and/or 8 post-implantation. In vitro induction of osteogenesis and osteoclastogenesis was established for identification of differentiation potentials evoked by icaritin in primary cultured precursor cells.ResultsThe results of radiographies and decalcified histology demonstrated more area and volume fractions of newly formed bone within bone defect sites implanted with P/T/ICT scaffold than that with P/T scaffold. Undecalcified histological results presented more osteoid and mineralized bone tissues, and also more active bone remodeling in P/T/ICT group than that in P/T group. The results of histological staining in osteoclast-like cells and newly formed vessels indicated favorable biocompatibility, rapid bioresorption and more new vessel growth in P/T/ICT scaffolds in contrast to P/T scaffolds. Based on in vitro induction, the results presented that icaritin could significantly facilitate osteogenic differentiation, while suppressed adipogenic differentiation. Meanwhile, icaritin demonstrated remarkable inhibition of osteoclastogenic differentiation.ConclusionThe finding that P/T/ICT composite scaffold can enhance bone regeneration in calvarial bone defects through facilitating effective bone formation and restraining excessive bone resorption.The translational potential of this articleThe osteogenic bioactivity of icaritin facilitated PLGA/TCP/icartin composite scaffold to exert significant bone regeneration in calvarial defects in rat model. It might form an optimized foundation for potential clinical validation in bone defects application.

Features of the structural and functional state of bone tissue in patients with generalized periodontitis who live in different anthropogenically loaded areas

Introduction. A research was conducted of the features of the structural and functional state of bone tissue in patients with generalized periodontitis with rheumatoid arthritis who live in different anthropogenically loaded areas. Aim. The aim of the research is to assess the bone tissue mineral density according to the indicators of densitometric researches and the level of a marker of bone metabolism in generalized periodontitis of I and II degree of severity. Material and methods. We examined 105 patients with GP of the I and II degree of severity, among whom were patients with rheumatoid arthritis who live in environmentally favorable and unfavorable areas. Peculiarities of the structural and functional state of bone tissue were assessed using an ultrasonic densitometer Sunlight Mini Omni TM and the level of a marker of bone tissue resorption of deoxypyridinoline in urine. Results. Patients with generalized periodontitis with rheumatoid arthritis who live in environmentally unfavorable areas, found the largest number of people with signs of osteopenia, osteoporosis and elevated levels of deoxypyridinoline. In particular, in generalized periodontitis of the II degree of severity with osteopenia – 14 people (48.27%), with osteoporosis – 9 people (31%), the level of deoxypyridinoline determined in women was 12.03 ± 0.16 n/mol, which in 2.2 times significantly higher than the group of healthy (p &lt; 0.001). Conclusions. According to densitometric parameters and the level of deoxypyridinoline in the urine, the acceleration of bone tissue resorption in patients with generalized periodontitis of the II degree of severity with rheumatoid arthritis who live in environmentally unfavorable areas was established.

The impact of humic acid additives on mineral metabolism of rabbits in the postnatal period of ontogenesis

Humic acids are characterized by chelating properties due to which they are able to influence the mineral metabolism in animals. Rabbits have species-specific characteristics of mineral metabolism, which distinguishes them from most species of mammals. For the experiment, 16 rabbits of 45-day-old of Hyplus breed were divided into the experimental and control group of 8 rabbits in each. The animals were 15 days in the preparatory period. The rabbits of the experimental group received humic acid additive individually with water in the amount of 5 mg/kg, the rabbits of the control group received pure water in the same amount. The ability of humic acid additive to increase the content of calcium, ionized calcium, iron, to correct the content of copper and zinc, and also to increase the activity of alkaline phosphatase in the blood serum of rabbits of the experimental group has been proved. We observed the early effect of the humic acid additive on increasing the content of iron and calcium ionized and a later effect on the activity of alkaline phosphatase and an increase in the content of copper in the blood serum. The influence of humic acid additive on the distribution of calcium, phosphorus, manganese, copper and zinc in bone tissue is determined. According to a histological study, there was a significant increase in the number of layers of osteons and osteoblasts in the bone tissue of the femur, an increase in the number of osteons and osteoblasts in the bone tissue of the sternum and an increase in the number of columns of chondrocytes and an increase in the number of chondrocytes in the column in the cartilaginous tissue of the sternum. The results of a histological study of bone tissue, together with an increase in structural macroelements in it and redistribution of osteotropic trace elements in the blood and bone tissue suggest the possibility of using a humic acid additive to intensify the growth and mineralization of bone tissue, which can improve the state of bone tissue of rabbits in the postnatal period ontogenesis.

The impact of humic acid additives on mineral metabolism of rabbits in the postnatal period of ontogenesis

Humic acids are characterized by chelating properties due to which they are able to influence the mineral metabolism in animals. Rabbits have species-specific characteristics of mineral metabolism, which distinguishes them from most species of mammals. For the experiment, 16 rabbits of 45-day-old of Hyplus breed were divided into the experimental and control group of 8 rabbits in each. The animals were 15 days in the preparatory period. The rabbits of the experimental group received humic acid additive individually with water in the amount of 5 mg/kg, the rabbits of the control group received pure water in the same amount. The ability of humic acid additive to increase the content of calcium, ionized calcium, iron, to correct the content of copper and zinc, and also to increase the activity of alkaline phosphatase in the blood serum of rabbits of the experimental group has been proved. We observed the early effect of the humic acid additive on increasing the content of iron and calcium ionized and a later effect on the activity of alkaline phosphatase and an increase in the content of copper in the blood serum. The influence of humic acid additive on the distribution of calcium, phosphorus, manganese, copper and zinc in bone tissue is determined. According to a histological study, there was a significant increase in the number of layers of osteons and osteoblasts in the bone tissue of the femur, an increase in the number of osteons and osteoblasts in the bone tissue of the sternum and an increase in the number of columns of chondrocytes and an increase in the number of chondrocytes in the column in the cartilaginous tissue of the sternum. The results of a histological study of bone tissue, together with an increase in structural macroelements in it and redistribution of osteotropic trace elements in the blood and bone tissue suggest the possibility of using a humic acid additive to intensify the growth and mineralization of bone tissue, which can improve the state of bone tissue of rabbits in the postnatal period ontogenesis.

Distribution of mechanical strain in equine distal metacarpal subchondral bone: A microCT-based finite element model

Microdamage accumulation and adaptation of subchondral bone subjected to intensive cyclic loading are important processes associated with catastrophic bone failure, and joint degeneration in athletic humans and racehorses. At the tissue-level, they lead to a spatial variation in bone tissue mineral density (TMD) which affects the response of the bone to mechanical load. Quantifying the spatial distribution of mechanical load within the subchondral bone is critical for understanding the mechanism of the joint failure. Previously, a gradient of TMD and mechanical properties has been reported under unconfined compression in osteochondral plugs. In the present study, we used micro computed tomography (μCT)-based finite element (FE) models of cartilage-bone to investigate the gradient of strain in the subchondral bone (SCB) from the third metacarpal (MC3) condyle of racehorses under simulated in situ compression. Non-destructive mechanical testing of specimens under high-rate compression provided the apparent-level modulus of SCB. FE models were analysed using unconfined and confined boundary conditions. Unconfined FE-predicted apparent-level gradient of modulus across the SCB thickness correlated well with the experimental results (R2 ​= ​0.72, p ​< ​0.05). The highest strain occurred in the most superficial SCB (0.5–2.5 ​mm deep to the cartilage-bone interface) under the simulated in-situ compression through articular cartilage. The findings of this study provide an estimation for the spatial distribution of mechanical strain within SCB in-situ in the presence of heterogeneous bone tissue which is commonly observed in joints subjected to intensive cyclic loading.

Fluid flow-induced cell stimulation in bone tissue engineering changes due to interstitial tissue formation in vitro.

In tissue engineering experiments in vitro, bioreactors have been used for applying wall shear stress (WSS) on cells to regulate cellular activities. To determine the loading conditions within bioreactors and to design tissue engineering products, in silico models are used. Previous in silico studies in bone tissue engineering (BTE) focused on quantifying the WSS on cells and the influence on appositional tissue growth. However, many BTE experiments also show interstitial tissue formation (i.e., tissue infiltrated in the pores rather than growing on the struts ‐ appositional growth), which has not been considered in previous in silico studies. We hereby used a multiscale fluid‐solid interaction model to quantify the WSS and mechanical strain on cells with interstitial tissue formation, taken from a reported BTE experiment. The WSS showed a high variation among different interstitial tissue morphologies. This is different to the situation under appositional tissue growth. It is found that a 35% filling of the pores results (by mineralised bone tissue) when the average WSS increases from 1.530 (day 0) to 5.735 mPa (day 28). Furthermore, the mechanical strain on cells caused by the fluid flow was extremely low (at the level of 10−14‐10−15), comparing to the threshold in a previous mechanobiological theory of osteogenesis (eg, 10−2). The output from this study offers a significant insight of the WSS changes during interstitial tissue growth under a constant perfusion flow rate in a BTE experiment. It has paved the way for optimising the local micro‐fluidic environment for interstitial tissue mineralisation.

Evaluation of osteosarcopenia treatment effectiveness in postmenopausal women

The aim: To assess the effectiveness of osteosarcopenia treatment with the use of systemic analysis methods. The results (criteria) developed allow to compare different methods of treatment effectiveness. The use of the multifunctional apparatus "Huber" in combination with osteotropic therapy (denosumab + Vit D metabolites) contributes to increase of musculoskeletal system functional capabilities: muscle strength, stability, coordination of movements. Besides it reduces functional limitations, promotes more effective treatment of structural and functional changes in bone tissue, increases bone tissue mineral density.

Protective Effects of Vitamin K Compounds on the Proteomic Profile of Osteoblasts under Oxidative Stress Conditions

Oxidative stress, which accompanies the pathogenesis of many bone diseases, contributes to the reduction of osteoblast activity, resulting in the inhibition of differentiation. This study aimed to assess the effect of vitamins K1 and K2 (MK4 and MK7) on the proteomic profile of human osteoblasts cell line under oxidative conditions induced by hydrogen peroxide (H2O2). The analysis was performed using QExactiveHF mass spectrometer with a nanoelectrospray ionization source. The osteoblast protein exposed to oxidative stress and vitamin K was compared with the proteome of cells exposed only to oxidative stress. Our proteomic analysis identified 1234 proteins changed after 5 days, 967 after 15 days, and 1214 after 20 days of culture. We observed the most frequent changes in the expression of proteins with catalytic activity or protein/DNA binding properties (45% and 40%, respectively). Significant changes were also observed in proteins with transcription/translation regulator activity (2–6%), regulators of molecular functions (5–6%), signal transducers (1–4%), transporters (4–6%), and structural molecules (3–5%). Our results clearly show that vitamins K protect cells from H2O2-induced changes in protein expression, primarily through their effects on transcriptional regulators and transporter proteins. As a result, vitamins K can support the formation, remodeling, and mineralization of bone tissue.

Low selenium levels are associated with decreased bone mineral densities

PurposeOsteoporosis has a high worldwide prevalence and detrimental consequences (e.g., increased fracture risk). The amount of bone mineral in bone tissue (i.e., bone mineral density [BMD]) is most widely used indicator of osteoporosis in clinical medicine. Selenium is an essential micronutrient for animals and humans. It is a cofactor for antioxidant enzyme reduction (e.g., glutathione peroxidase). It also enhances immune surveillance and modulates cell proliferation. Study findings on the associations between BMD and selenium levels are inadequate and contradictory. The purpose of this study was to examine the associations between hair selenium levels and lumbar spine and femur BMD values. MethodsUsing a cross-sectional study design, we assessed the associations between hair selenium levels and BMD values in 1,167 Korean adults who underwent a health check-up. Each subject was assigned to one of two groups based on BMD (normal group [T-score ≥ -1.0] or low BMD group [T-score < -1.0]). The associations between hair selenium levels and the risk for low BMD were estimated using multivariate logistic regression models. ResultsStudy participants with lower hair selenium levels were older and had higher phosphorous, alkaline phosphatase, and osteocalcin levels. They also had lower BMDs, corrected serum calcium levels, uric acid levels, and creatinine clearance. Participants with low BMDs had significantly lower hair selenium levels (P < 0.001). After adjusting for osteoporosis-related risk factors, the risk of a low BMD was significantly greater for the lower hair selenium quartile groups (P = 0.045). ConclusionIn conclusion, this study found that lower hair selenium levels were associated with low BMD values, independent of the other osteoporosis risk factors examined. Further prospective studies are warranted to determine the role of selenium in the development of osteoporosis.

Establishing Normative Embryonic and Early Postnatal Cranial Bone Volume and Density Values for C57BL/6J Laboratory Mice

We provide normative data for cranial bone volume and tissue mineral density (TMD) for embryonic and early postnatal C57BL/6J mice that can be used as control data for researchers using experimental mouse models. C57BL/6J mice were selected based on their common usage in experimental research. Our sample includes 3 males and 3 females at four ages: embryonic day (E) 15.5, E17.5, postnatal day (P) 0, and P7. MicroCT images were acquired by the Center for Quantitative Imaging at the Pennsylvania State University using the General Electric v|tom|x L300 nano/microCT system. Prior to data collection, all postcranial bones were electronically removed from the scan using Avizo 9.4, and then background noise was removed from each scan using a 3D median filter. Isosurfaces were reconstructed to represent cranial bone based on a hydroxyapatite phantom that was scanned with each specimen. To maintain consistency between specimens and across age groups, we used 85 mg/cm3 as the minimum threshold to create isosurfaces and segment bone for this study. Twenty cranial bones were individually segmented for each specimen, and volume and TMD were estimated in Avizo. After correcting for multiple testing, no significant differences were found in bone volume or TMD between males and females for any of the examined cranial bones at any age, and data were pooled for analyses. As expected, volume of ossified bone increased with age from E15.5 to P7. The number of ossification centers present in a single individual is highly variable at E15.5 (ranging from 2 – 10), with all bones present by P7. Most of the measured bones consistently increased in TMD with age, with several exceptions. The palatine, vomer, and zygomatic bones each decreased in TMD from P0 to P7. The TMD of the maxilla also decreased slightly from E17.5 to P0, but then increased from P0 to P7. No significant patterns of development related to originating cell population (mesoderm v. neural crest) or mode of ossification (endochondral v. intramembranous) were apparent. These data can serve as a reference standard for future studies that examine craniofacial growth and disease models using mice bred on a C57BL/6J background.Support or Funding InformationNational Science Foundation Grant BCS‐1731909, NIDCR R01DE027677 and R01 DE022988, and the Pennsylvania State University Energy and Environmental Sustainability Laboratories Green Seed Grant

Enhancement of tendon-bone interface healing and graft maturation with cylindrical titanium-web (TW) in a miniature swine anterior cruciate ligament reconstruction model: histological and collagen-based analysis

BackgroundTendon-bone interface healing and ligamentization of the graft in anterior cruciate ligament (ACL) reconstruction with autografts are important factors affecting treatment outcome. This study aimed to investigate the effectiveness of a cylindrical titanium-web (TW) in tendon-bone interface healing and graft maturation in ACL reconstruction.MethodsFourteen mature female CLAWN miniature swine underwent bilateral ACL reconstructions with patellar tendon (PT) autografts. In one limb, the TW/tendon complex was placed into the proximal side of the tibial tunnel. Only the graft was transplanted into the tunnel in the control limb. The proximal side of the graft was sutured into the stump of the native ACL and the distal end was stapled to the tibia. The animals were euthanized at 4 and 15 weeks postoperatively, for histological and biochemical analyses.ResultsMicroscopic images in TW limbs showed that ingrowth of tendon-like tissue and mineralized bone tissue into the TW connected the bone and the tendon directly. In contrast, fibrous tissue intervened between the bone and tendon in the control limbs. The total amount of collagen cross-links (which defines the strength of collagen fibers) and the maturation of collagen cross-links in TW tendons were significantly higher (p < 0.05) than those of control limbs. There was no significant difference in the ratio of dihydroxy-lysinonorleucine to hydroxy-lysinonorleucine (an indicator of tissue specific collagen maturation) between TW tendons and that of the native PT.ConclusionsTW promoted the maturation and formation of collagen cross-links in the grafted tendon while maintaining the cross-links pattern of native tendon collagen, and enabled direct binding of tendon to bone.