Collagen Mineralization Research Articles

Influence of Biofield Treated Vitamin D<sub>3</sub> on Proliferation, Differentiation, and Maturation of Bone-Related Parameters in MG-63 Cell-Line

The study was aimed to evaluate the effect of Consciousness Energy Healing-based vitamin D3 and DMEM medium on bone health parameters such as alkaline phosphatase (ALP), collagen, and bone mineralization in human bone osteosarcoma cells (MG-63). The test items (vitamin D3 and DMEM), were divided into two parts. One part of each sample was received the Biofield Energy Treatment by Dimitrius Anagnos and those samples were denoted as the Biofield Energy Treated (BT) samples, while the other parts of each sample were referred as the untreated test items (UT). The test samples were found as safe in the tested concentrations by MTT cell viability assay. The level of ALP was significantly increased by 74.86% in the BT-DMEM + BT-Test item and 40.17% in the UT-DMEM + BT-Test item group at 0.1 and 50 µg/mL, respectively compared to the UT-DMEM + UT-Test item group. Moreover, collagen level was significantly increased by 228.22%, 185.40%, and 256.69% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item groups, respectively at 0.1 µg/mL compared to the UT-DMEM + UT-Test item group. Further, the collagen level was significantly increased by 88.61% and 130.65% in the BT-DMEM + UT-Test item and BT-DMEM + BT-Test item groups, respectively at 1 µg/mL compared to the untreated group. Apart from this, the percent of bone mineralization was distinctly enhanced by 98.61%, 111.67%, and 68.26% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item groups, respectively at 0.1 µg/mL compared to the untreated group. Additionally, the percentage of bone mineralization was significantly increased by 83.3%, 99.52%, and 50.26% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item groups, respectively at 1 µg/mL compared to the untreated group. Altogether, the Biofield Energy Treated vitamin D3 was significantly improved the bone health parameters and it could be an alternative approach for nutraceutical supplement to combat vitamin D3 deficiency and able to fight against various bone-related disorders including rickets, low bone density, osteomalacia, bone and joint pain, bone fractures, osteoporosis, osteoma, osteogenesis imperfecta, Paget’s disease, deformed bones, chondrodystrophia fetalis, stress management and prevention, autoimmune and inflammatory diseases, and anti-aging by improving overall health.

The Potential Benefits of Biofield Energy Treated Vitamin D<sub>3</sub> on Bone Mineralization in Human Bone Osteosarcoma Cells (MG-63)

The study was aimed to evaluate the potential of Consciousness Energy Healing based vitamin D3 and DMEM medium on bone health. The test items, were divided into two parts. One part of each sample received the Consciousness Energy Healing Treatment by Aileen Carol Lee and those samples were labeled as the Biofield Energy Treated (BT) samples, while the other parts of each sample were denoted as the untreated test items (UT). ALP, collagen, and bone mineralization activities were performed to assess bone health in human bone osteosarcoma cells (MG-63). The cell viability assay (MTT) data showed that the test samples were found as safe in the tested concentrations. The level of ALP was significantly increased by 251.16%, 103.75%, and 119.55% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item, respectively at 50 µg/mL compared to the UT-DMEM + UT-Test item group. Further, the ALP level was significantly elevated by 194.1%, 72.34%, and 65.31% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item groups, respectively at 100 µg/mL compared to the UT-DMEM + UT-Test item group. Collagen was significantly increased by 12.88%, 64.51%, and 71.50% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item groups, respectively at 100 µg/mL compared to the untreated group. Further, the collagen level was significantly increased by 50.29% and 52.48% in the BT-DMEM + UT-Test item and BT-DMEM + BT-Test item, respectively at 50 µg/mL compared to the untreated group. Additionally, the percent of bone mineralization was distinctly increased by 64.46% and 94.16% in the UT-DMEM + BT-Test item and BT-DMEM + UT-Test item groups, respectively at 100 µg/mL compared to the untreated group. The percent of bone mineralization was distinctly increased by 26.59% and 28.33% in the BT-DMEM + UT-Test item group at 10 and 50 µg/mL, respectively compared to the UT-DMEM + UT-Test item group. Overall, the Biofield Energy Treated vitamin D3 was remarkably improved the bone health parameters and it could be a powerful alternative nutraceutical supplement to combat vitamin D3 deficiency and fight against various bone related problems including low bone density, osteoporosis, osteogenesis imperfecta, Paget’s disease of bone, rickets, osteomalacia, bone and joint pain, bone fractures, deformed bones, osteoma, chondrodystrophia fetalis, autoimmune and inflammatory diseases, stress management and prevention, and anti-aging by improving overall health.

Role of Vitamin D<sub>3</sub> on Alkaline Phosphatase, Collagen, and Bone Mineralization: Impact of Biofield Energy Healing Treatment

Role of Vitamin D<sub>3</sub> on Alkaline Phosphatase, Collagen, and Bone Mineralization: Impact of Biofield Energy Healing Treatment

Assessment of Bone Health After Treatment with the Consciousness Energy Healing Treated Vitamin D<sub>3</sub> in Human Bone Osteosarcoma Cells (MG-63)

Osteoporosis is associated with increased mortality and significant economic and health burden now-a-days. The study was aimed to evaluate the potential of Consciousness Energy Healing based vitamin D3 and DMEM medium on bone health. The test items, were divided into two parts. One part of each sample received the Consciousness Energy Healing Treatment by Carola Marina Sand and those samples were labeled as the Biofield Energy Treated (BT) samples, while the other parts of each sample were denoted as the untreated test items (UT). Various parameters were performed for the assessment of bone health such as ALP, collagen, and bone mineralization in human bone osteosarcoma cells (MG-63). The cell viability (MTT) data showed that the test samples were found as safe in the tested concentrations. The level of ALP was significantly increased by 420.64%, 311.08%, and 532.17% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item, respectively at 1µg/mL compared to the UT-DMEM + UT-Test item group. Further, the ALP level was significantly elevated by 213.69%, 135.46%, and 42.76% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item groups, respectively at 10µg/mL compared to the untreated. Collagen was significantly increased by 228.22%, 185.40%, and 256.69% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item, respectively at 0.1µg/mL compared to the untreated. Further, the collagen level was significantly increased by 88.61% and 130.65% in the BT-DMEM + UT-Test item and BT-DMEM + BT-Test item, respectively at 1µg/mL compared to the untreated. Besides, the percent of bone mineralization was distinctly increased by 118.35%, 266.94%, and 118.25% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item groups, respectively at 50µg/mL compared to the untreated. The percent of bone mineralization was distinctly increased by 88.29%, 288.75%, and 86.25% in the UT-DMEM + BT-Test item, BT-DMEM + UT-Test item, and BT-DMEM + BT-Test item, respectively at 100µg/mL compared to the untreated. Overall, the Biofield Energy Treated vitamin D3 was tremendously improved the bone health parameters and it could be a powerful alternative nutraceutical supplement to combat vitamin D3 deficiency and fight against various bone-related disorders including osteoporosis, low bone density, osteogenesis imperfecta, Paget’s disease, rickets, osteomalacia, deformed bones, chondrodystrophia fetalis, autoimmune and inflammatory diseases, stress management and prevention, and anti-aging by improving overall health.

The effect of weight loss on body composition, serum bone markers, and adipokines in prepubertal obese children after 1-year intervention

ABSTRACTPurpose/Aim: The influence of weight loss on bone turnover and bone quality in childhood remains controversial, but it may implicate interactions between adiposity and bone metabolism. Therefore, we studied the relationships between bone markers and adipokines during weight loss in obese children. Materials and Methods: We determined serum leptin, soluble leptin receptor, adiponectin, bone alkaline phosphatase (BALP), C-terminal telopeptide of type I collagen (CTX-I), osteocalcin (OC), carboxylated-OC (Gla-OC), undercarboxylated-OC (Glu-OC), sclerostin, body composition, and bone mineral density (BMD) in 40 obese prepubertal children before and after therapy. The control group, matched for sex and age, consisted of 40 non-obese children. Results: We found that values of the total body less head-bone mineral content (TBLH-BMC) and TBLH-BMD were significantly increased, but TBLH-BMD Z-score was decreased by 25% (p = 0.002) in obese children with weight loss after therapy. We observed increases of CTX-I to OC ratio (p = 0.009), and Gla-OC concentrations (p = 0.049). Changes in TBLH-BMD Z-score in patients were positively correlated with changes in BMI Z-score (p = 0.001), percentage of fat mass (p = 0.004), and BALP activity (p = 0.01). Changes in BALP activity were negatively correlated (p < 0.001) with changes in adiponectin concentrations, while changes in sclerostin levels were positively correlated (p = 0.001) with leptin changes. Conclusions: We suggest that alterations in adipokines metabolism were associated with a lower rate of bone mineral accrual as a result of decreased bone formation rather than increased bone resorption. The lower rate of bone mass accrual in weight losing children may be an effect of reduced BALP levels related to increase in adiponectin levels.

Strontium-modification of porous scaffolds from mineralized collagen for potential use in bone defect therapy

The present study describes the development and characterization of strontium(II)-modified biomimetic scaffolds based on mineralized collagen type I as potential biomaterial for the local treatment of defects in systemically impaired (e.g. osteoporotic) bone. In contrast to already described collagen/hydroxyapatite nanocomposites calcium was substituted with strontium to the extent of 25, 50, 75 and 100mol% by substituting the CaCl2-stock solution (0.1M) with SrCl2 (0.1M) during the scaffold synthesis. Simultaneous fibrillation and mineralization of collagen led to the formation of collagen-mineral nanocomposites with mineral phases shifting from nanocrystalline hydroxyapatite (Sr0) over poorly crystalline Sr-rich phases towards a mixed mineral phase (Sr100), consisting of an amorphous strontium phosphate (identified as Collin's salt, Sr6H3(PO4)5∗2 H2O, CS) and highly crystalline strontium hydroxyapatite (Sr5(PO4)3OH, SrHA). The formed mineral phases were characterized by transmission electron microscopy (TEM) and RAMAN spectroscopy. All collagen/mineral nanocomposites with graded strontium content were processed to scaffolds exhibiting an interconnected porosity suitable for homogenous cell seeding in vitro. Strontium ions (Sr2+) were released in a sustained manner from the modified scaffolds, with a clear correlation between the released Sr2+ concentration and the degree of Sr-substitution. The accumulated specific Sr2+ release over the course of 28days reached 141.2μg (~27μgmg−1) from Sr50 and 266.1μg (~35μgmg−1) from Sr100, respectively. Under cell culture conditions this led to maximum Sr2+ concentrations of 0.41mM (Sr50) and 0.73mM (Sr100) measured on day 1, which declined to 0.08mM and 0.16mM, respectively, at day 28. Since Sr2+ concentrations in this range are known to have an osteo-anabolic effect, these scaffolds are promising biomaterials for the clinical treatment of defects in systemically impaired bone.

Using biomimetic polymers in place of noncollagenous proteins to achieve functional remineralization of dentin tissues.

In calcified tissues such as bones and teeth, mineralization is regulated by an extracellular matrix, which includes non-collagenous proteins (NCP). This natural process has been adapted or mimicked to restore tissues following physical damage or demineralization by using polyanionic acids in place of NCPs, but the remineralized tissues fail to fully recover their mechanical properties. Here we show that pre-treatment with certain amphiphilic peptoids, a class of peptide-like polymers consisting of N-substituted glycines that have defined monomer sequences, enhances ordering and mineralization of collagen and induces functional remineralization of dentin lesions in vitro. In the vicinity of dentin tubules, the newly formed apatite nano-crystals are co-aligned with the c-axis parallel to the tubular periphery and recovery of tissue ultrastructure is accompanied by development of high mechanical strength. The observed effects are highly sequence-dependent with alternating polar and non-polar groups leading to positive outcomes while diblock sequences have no effect. The observations suggest aromatic groups interact with the collagen while the hydrophilic side chains bind the mineralizing constituents and highlight the potential of synthetic sequence-defined biomimetic polymers to serve as NCP mimics in tissue remineralization.

Numerical analysis of mineral crystals on mechanical properties of mineralized collagen fibers

AbstractBone, with excellent mechanical properties, can adapt to a variety of external forces through adjust its complex hierarchical structure. The basis of the hierarchical structure is mineralized collagen fibers, which consist of mineral crystals and collagen fibers. To better understand the mechanical properties of mineralized collagen fibers, we establish a series of representative volume element models of mineralized collagen fibers based on the different arrangement of mineral crystals in the collagen fibers. The effects of crystal aspect ratio, volume fraction, and crystal defect on the effective elastic modulus and Poisson's ratio of mineralized collagen fibers are calculated by combining the homogenization theory with the finite element method. Results show that the elastic modulus of mineralized collagen fibers can be regulated effectively by adjusting the aspect ratio and volume fraction of crystals. This research explains the mechanical advantages of mineralized collagen fibers in the structure, provides a basis for the calculation of high level structure of bone and offers insight into the design of bionic composite materials.

Effect of proanthocyanidin on ultrastructure and mineralization of dentine collagen

ObjectiveProanthocyanidin (PA) is a natural collagen cross-linker that has been used in dentine matrix biomodification for reparative and preventive therapies. This study evaluated the ultrastructure of collagen after its interaction with PA. Furthermore, the mineralization of PA-biomodified collagen matrix was observed. MethodsTen freshly extracted sound human molars were sectioned into 0.5mm×1.7mm×7mm beams for ultrastructural evaluation of PA and dentine matrix under Field Emission Scanning Electron Microscopy (FESEM) and Transmission Electron Microscopy (TEM). Specimens for TEM were completely demineralized and divided into three groups according to PA treatments: deionized water, 2% PA and 6.5% PA. The specimens were fixed, dehydrated, sectioned and examined using TEM. Specimens for FESEM were lightly conditioned with EDTA and similarly divided into the three groups for observation using FESEM. Type I collagen from calf skin was used to analyse the mineral interaction after treatment with 6.5% PA. Formvar- and carbon-coated 400-mesh Ni grids (EMS, Hatfiels, PA, USA) were placed over a 2mg/mL collagen solution prepared from calf skin-derived Type I collagen to achieve self-assembly of collagen fibrils. Grids were treated with 6.5% PA and divided into two groups. One group was floated over a remineralization solution containing 20mM HEPES, 2.25mM CaCl2-2H2O, 1.35mM KH2PO4, 3.08mM NaN3 and 130mM KCl and the other group was over a CPP-ACP solution (Tooth mousse 1:100 dilution with deionized water). The floating samples were kept in a 37°C and 100% humidity chamber. Grids were taken out at selected time durations (24h, 48h and 72h for mineralization solution/24h for CPP-ACP) and observed under TEM without staining. Selected area electron diffractions (SAEDs) were performed at 110kV. ResultsFollowing treatment of demineralized dentine collagen matrix with PA, the size and number of interfibrillar spaces were reduced. The collagen fibrils aggregated together with a reduction in porosity. A characteristic banding pattern of collagen fibrils was observed under TEM. Treatment of PA-biomodified collagen fibrils with remineralization solution increased mineral aggregation along its long axis, when compared to the control group. Furthermore, treatment of PA-biomodified collagen fibrils with CPP-ACP solution enhanced mineral uptake and deposition as well as initiated apatite formation within 24h. ConclusionProanthocyanidin alters the ultrastructure of demineralized dentine collagen matrix. The PA-biomodified collagen matrix promotes remineralization.

Bioreactor culture duration of engineered constructs influences bone formation by mesenchymal stem cells.

Perfusion culture of mesenchymal stem cells (MSCs) seeded in biomaterial scaffolds provides nutrients for cell survival, enhances extracellular matrix deposition, and increases osteogenic cell differentiation. However, there is no consensus on the appropriate perfusion duration of cellular constructs invitro to boost their bone forming capacity invivo. We investigated this phenomenon by culturing human MSCs in macroporous composite scaffolds in a direct perfusion bioreactor and compared their response to scaffolds in continuous dynamic culture conditions on an XYZ shaker. Cell seeding in continuous perfusion bioreactors resulted in more uniform MSC distribution than static seeding. We observed similar calcium deposition in all composite scaffolds over 21 days of bioreactor culture, regardless of pore size. Compared to scaffolds in dynamic culture, perfused scaffolds exhibited increased DNA content and expression of osteogenic markers up to 14 days in culture that plateaued thereafter. We then evaluated the effect of perfusion culture duration on bone formation when MSC-seeded scaffolds were implanted in a murine ectopic site. Human MSCs persisted in all scaffolds at 2 weeks invivo, and we observed increased neovascularization in constructs cultured under perfusion for 7 days relative to those cultured for 1 day within each gender. At 8 weeks post-implantation, we observed greater bone volume fraction, bone mineral density, tissue ingrowth, collagen density, and osteoblastic markers in bioreactor constructs cultured for 14 days compared to those cultured for 1 or 7 days, and acellular constructs. Taken together, these data demonstrate that culturing MSCs under perfusion culture for at least 14 days invitro improves the quantity and quality of bone formation invivo. This study highlights the need for optimizing invitro bioreactor culture duration of engineered constructs to achieve the desired level of bone formation.

Synergistic effects of the combined use of human-cultured periosteal sheets and platelet-rich fibrin on bone regeneration: An animal study.

A human‐cultured alveolar bone‐derived periosteal (hCP) sheet is an osteogenic grafting material used clinically in periodontal regenerative therapy, while platelet‐rich fibrin (PRF), a platelet concentrate with fibrin clot, is considered to augment the wound healing process. Therefore, whether the combined use of hCP‐PRF complex could facilitate bone regeneration synergistically was evaluated in animal models. Human periosteal segments (1 × 1 mm) were cultured initially on plastic dishes and formed an hCP sheet. The hCP sheet was implanted with freshly prepared human PRF into subcutaneous tissue (hCP: n = 4, hCP + PRF: n = 4) and 4 mm diameter calvarial bone defect models (hCP: n = 4, hCP + PRF: n = 4, control [defect‐only]: n = 4) that prepared in nude mice. At 4 weeks postimplantation, new bone formation was evaluated by using μCT. Cell growth and neovascularization were evaluated by histochemical and immunohistological methods. In the subcutaneous tissue, mineral deposit formation, collagen deposition, and number of vessels were higher in the hCP + PRF group than in the hCP alone group. In the calvarial defect models, new bone formation was significantly higher in the hCP + PRF group than in the hCP alone group and defect‐only control group. The numbers of vessels and PCNA‐positive cells in calvarial defects were also increased in the hCP + PRF group more than in the hCP alone group. Platelet‐rich fibrin preparations support the proliferation and the growth of periosteal cells to form well‐combined active biological materials. Platelet‐rich fibrin also stimulates the local angiogenesis in the implantation site. Therefore, the combined use of hCP and PRF could be clinically applicable in bone regeneration therapy.

* Biomineralized Recombinant Collagen-Based Scaffold Mimicking Native Bone Enhances Mesenchymal Stem Cell Interaction and Differentiation.

The need of synthetic bone grafts that recreate from macro- to nanoscale level the biochemical and biophysical cues of bone extracellular matrix has been a major driving force for the development of new generation of biomaterials. In this study, synthetic bone substitutes have been synthesized via biomimetic mineralization of a recombinant collagen type I-derived peptide (RCP), enriched in tri-amino acid sequence arginine-glycine-aspartate (RGD). Three-dimensional (3D) isotropic porous scaffolds of three different compositions are developed by freeze-drying: non-mineralized (RCP, as a control), mineralized (Ap/RCP), and mineralized scaffolds in the presence of magnesium (MgAp/RCP) that closely imitate bone composition. The effect of mineral phase on scaffold pore size, porosity, and permeability, as well as on their in vitro kinetic degradation, is evaluated. The ultimate goal is to investigate how chemical (i.e., surface chemistry and ion release from scaffold) together with physical signals (i.e., surface nanotopography) conferred via biomimetic mineralization can persuade and guide mesenchymal stem cell (MSC) interaction and fate. The three scaffold compositions showed optimum pore size and porosity for osteoconduction, without significant differences between them. The degradation tests confirmed that MgAp/RCP scaffolds presented higher reactivity under physiological condition compared to Ap/RCP ones. The in vitro study revealed an enhanced cell growth and proliferation on MgAp/RCP scaffolds at day 7, 14, and 21. Furthermore, MgAp/RCP scaffolds potentially promoted cell migration through the inner areas reaching the bottom of the scaffold after 14 days. MSCs cultured on MgAp/RCP scaffolds displayed higher gene and protein expressions of osteogenic markers when comparing them with the results of those MSCs grown on RCP or Ap/RCP scaffolds. This work highlights that mineralization of recombinant collagen mimicking bone mineral composition and morphology is a versatile approach to design smart scaffold interface in a 3D model guiding MSC fate.

One-month spaceflight compromises the bone microstructure, tissue-level mechanical properties, osteocyte survival and lacunae volume in mature mice skeletons

The weightless environment during spaceflight induces site-specific bone loss. The 30-day Bion-M1 mission offered a unique opportunity to characterize the skeletal changes after spaceflight and an 8-day recovery period in mature male C57/BL6 mice. In the femur metaphysis, spaceflight decreased the trabecular bone volume (−64% vs. Habitat Control), dramatically increased the bone resorption (+140% vs. Habitat Control) and induced marrow adiposity invasion. At the diaphysis, cortical thinning associated with periosteal resorption was observed. In the Flight animal group, the osteocyte lacunae displayed a reduced volume and a more spherical shape (synchrotron radiation analyses), and empty lacunae were highly increased (+344% vs. Habitat Control). Tissue-level mechanical cortical properties (i.e., hardness and modulus) were locally decreased by spaceflight, whereas the mineral characteristics and collagen maturity were unaffected. In the vertebrae, spaceflight decreased the overall bone volume and altered the modulus in the periphery of the trabecular struts. Despite normalized osteoclastic activity and an increased osteoblast number, bone recovery was not observed 8 days after landing. In conclusion, spaceflight induces osteocyte death, which may trigger bone resorption and result in bone mass and microstructural deterioration. Moreover, osteocyte cell death, lacunae mineralization and fatty marrow, which are hallmarks of ageing, may impede tissue maintenance and repair.

Mineralized Collagen-Based Composite Bone Materials for Cranial Bone Regeneration in Developing Sheep.

Cranial bone defects remain a great challenging problem in clinical settings, the influences of which are serious because of the intricate complications and related social problems, especially for young children with rapidly growing skulls. Currently, an increasing number of bone materials are being developed for cranial bone defects repair. In this study, two different biodegradable composite bone materials based on mineralized collagen (MC), with compact/porous structure, were constructed to promote bone regeneration for large cranial bone defect repair of one-month-old baby sheep. The porous MC (pMC) scaffold had interconnected porous structure with a porosity of about 73% and a 20-150 μm pore size range, and the compact MC (cMC) showed no distinct pore structure. Mechanical tests indicated that the compressive strength and elastic modulus of cMC and pMC were comparable with those of natural compact and cancellous bone, respectively. Both of these two MC scaffolds possessed good biocompatibility and supported osteoblasts adhesion and proliferation in vitro. A one-month-old sheep cranial bone defect model was first established to investigate the cranial bone regeneration behaviors in vivo, which was evaluated by CT imaging, X-rays scans, and histological assessments. It was found that the pMC promoted bone ingrowth from the diploic layer of surrounding cranium and dura mater-derived osteogenesis at three months after surgery, along with gradual biodegradation. In contrast, the cMC had very little biodegradation but could promote bone formation beneath the scaffold through dura mater-derived osteogenesis pathway. Furthermore, Ti-mesh restricted the growth of surrounding cranial bone in the rapidly growing sheep, thereby causing obvious deformation of the skull at six months after surgery, whereas no visible geometric deformation of skull occurred in the cMC and pMC groups. Our findings suggested that the MC-based composite bone materials have great promise for the repair of large cranial bone defects in a developing skull.

A high-fat diet can affect bone healing in growing rats.

A high-fat diet (HFD) can have a negative effect on bone quality in young and old people. Although bone healing in children is normally efficient, there is no evidence that children who have a diet rich in fat have compromised bone fracture regeneration compared with children with recommended dietary fat levels. The purpose of the present study was to evaluate the effects of an HFD on bone healing in growing female rats. Twenty-six postweaning female Wistar rats were divided into two groups (13 animals per group): a standard diet (SD) group and an HFD (with 60% of energy from fat) group. The rats received the assigned diets for 5weeks, and in the third week they were submitted to an osteotomy procedure of the left tibia. Body mass and feed intake were recorded during the experiment. One day before euthanasia, an insulin tolerance test was performed. After euthanasia, the tibiae were removed and analyzed by densitometry, mechanical testing, histomorphometry, stereology and immunohistochemistry. An HFD caused an adaptive response to maintain energetic balance by decreasing feed intake and causing insulin insensitivity. There was no change in bone mineral density, collagen amount and immunostaining for bone formation, but maximal load and stiffness were decreased in the HFD group. In addition, bone volume had a tendency to be higher in the SD group than in the HFD group. Compared with rats receiving an SD, growing rats receiving an HFD for 5weeks had similar bone mineral density but altered mechanical properties at the osteotomy defect site.

Modeling of Stiffness and Strength of Bone at Nanoscale.

Two distinct geometrical models of bone at the nanoscale (collagen fibril and mineral platelets) are analyzed computationally. In the first model (model I), minerals are periodically distributed in a staggered manner in a collagen matrix while in the second model (model II), minerals form continuous layers outside the collagen fibril. Elastic modulus and strength of bone at the nanoscale, represented by these two models under longitudinal tensile loading, are studied using a finite element (FE) software abaqus. The analysis employs a traction-separation law (cohesive surface modeling) at various interfaces in the models to account for interfacial delaminations. Plane stress, plane strain, and axisymmetric versions of the two models are considered. Model II is found to have a higher stiffness than model I for all cases. For strength, the two models alternate the superiority of performance depending on the inputs and assumptions used. For model II, the axisymmetric case gives higher results than the plane stress and plane strain cases while an opposite trend is observed for model I. For axisymmetric case, model II shows greater strength and stiffness compared to model I. The collagen-mineral arrangement of bone at nanoscale forms a basic building block of bone. Thus, knowledge of its mechanical properties is of high scientific and clinical interests.

Shear-mediated orientational mineralization of bone apatite on collagen fibrils.

Fluid shear stress (FSS) is regarded as a predominant stimulus to bone cells and matrix under physiological conditions. The influence of FSS on mineralization of collagen is explored by exposure to an environment of constant FSS values less than 2.0 Pa. At the designated time points, the apatite/collagen composites were characterized by X-ray diffraction, calcium/phosphorus assay, differential scanning calorimetry, transmission electron microscopy, and selected area electron diffraction. The results show that FSS within a certain range, especially within 1.5 Pa, has a positive effect on collagen mineralization, as illustrated by the enhanced degree of collagen self-assembly, accelerated speed of amorphous calcium phosphate (ACP) formation and transition, and well-organized apatite structure and orientation. Under the condition of FSS, the size of ACP is also well controlled, and the minerals disperse inside collagen fibrils; this leads to intrafibrillar mineralization. These findings are helpful for understanding the mechanism of mineralization in natural bone tissue and deepen the knowledge of biomechanics of this process.

Biomimetics of Bone Implants: The Regenerative Road.

The current strategies for healing bone defects are numerous and varied. At the core of each bone healing therapy is a biomimetic mechanism, which works to enhance bone growth. These range from porous scaffolds, bone mineral usage, collagen, and glycosaminoglycan substitutes to transplanted cell populations. Bone defects face a range of difficulty in their healing, given the composite of dense outer compact bone and blood-rich inner trabecular bone. As such, the tissue possesses a number of inherent characteristics, which may be clinically harnessed as promoters of bone healing. These include mechanical characteristics, mineral composition, native collagen content, and cellular fraction of bone. This review charts multiple biomimetic strategies to help heal bony defects in large and small osseous injury sites, with a special focus on cell transplantation.

Calcium concentration dependent collagen mineralization

Mineralization of collagen fibrils is a regular combination process of organic and mineral components mainly involving calcium, phosphate and collagen. We report the influence of calcium to the self-assembly of collagen by changing the concentration of calcium ion in the process of mineralization. Low concentration of calcium results in the well collagen self-assembly while poor mineral crystallization. Relatively, high concentration of calcium can hinder collagen self-assembly, whereas it is benefited to mineral crystallization. We also reveal that collagen self-assembly happens in advance of the formation of better mineral crystals. These results interpret the mechanism of collagen mineralization further.

A new multiscale micromechanical model of vertebral trabecular bones.

A new three-dimensional (3D) multiscale micromechanical model has been suggested as adept at predicting the overall linear anisotropic mechanical properties of a vertebral trabecular bone (VTB) highly porous microstructure. A nested 3D modeling analysis framework spanning the multiscale nature of the VTB is presented herein. This hierarchical analysis framework employs the following micromechanical methods: the 3D parametric high-fidelity generalized method of cells (HFGMC) as well as the 3D sublaminate model. At the nanoscale level, the 3D HFGMC method is applied to obtain the effective elastic properties of a representative unit cell (RUC) representing the mineral collagen fibrils composite. Next at the submicron scale level, the 3D sublaminate model is used to generate the effective elastic properties of a repeated stack of multilayered lamellae demonstrating the nature of the trabeculae (bone-wall). Thirdly, at the micron scale level, the 3D HFGMC method is used again on a RUC of the highly porous VTB microstructure. The VTB-RUC geometries are taken from microcomputed tomography scans of VTB samples harvested from different vertebrae of human cadavers [Formula: see text]. The predicted anisotropic overall elastic properties for native VTBs are, then, examined as a function of age and sex. The predicted results of the VTBs longitudinal Young's modulus are compared to reported values found in the literature. The proposed 3D nested modeling analysis framework provides a good agreement with reported values of Young's modulus of single trabeculae as well as for VTB-RUC in the literature.