Bone Calcium Deposition Research Articles

Bone regeneration driven by a nano-hydroxyapatite/chitosan composite bioaerogel for periodontal regeneration.

The most recent progress in reconstructive therapy for the management of periodontitis and peri-implantitis bone defects has relied on the development of highly porous biodegradable bioaerogels for guided bone regeneration. The objective of this work was to evaluate in vitro the osteoinduction of periodontal-originating cells (human dental follicle mesenchymal cells, DFMSCs) promoted by a nano-hydroxyapatite/chitosan (nHAp/CS) bioaerogel, which was purified and sterilized by a sustainable technique (supercritical CO2). Moreover, the in vivo bone regeneration capacity of the nHAp/CS bioaerogel was preliminarily assessed as a proof-of-concept on a rat calvaria bone defect model. The quantification of DNA content of DFMSCs seeded upon nHAp/CS and CS scaffolds (control material) showed a significant increase from the 14th to the 21st day of culture. These results were corroborated through confocal laser scanning microscopy analysis (CLSM). Furthermore, the alkaline phosphatase (ALP) activity increased significantly on the 21st day, similarly for both materials. Moreover, the presence of nHAp promoted a significantly higher expression of osteogenic genes after 21days when compared to CS scaffolds and control. CLSM images of 21days of culture also showed an increased deposition of OPN over the nHAp/CS surface. The in vivo bone formation was assessed by microCT and histological analysis. The in vivo evaluation showed a significant increase in bone volume in the nHAp/CS test group when compared to CS and the empty control, as well as higher new bone formation and calcium deposition within the nHAp/CS structure. Overall, the present study showed that the nHAp/CS bioaerogel could offer a potential solution for periodontal and peri-implant bone regeneration treatments since the in vitro results demonstrated that it provided favorable conditions for DFMSC proliferation and osteogenic differentiation, while the in vivo outcomes confirmed that it promoted higher bone ingrowth.

Abstract 2920: In vitro assays for investigating the effects of cancer therapeutics on bone

Abstract Bone microenvironment is an important factor in regulating bone metastasis. When cancer cells home to bone they secrete factors that stimulate osteoclast activity leading to increased bone resorption. Stimulatory factors released from the resorbed bone matrix in turn promote proliferation of cancer cells and this process, referred as the vicious cycle, often leads to osteolytic lesions in bone when osteoclastic bone resorption exceeds osteoblastic bone formation. The vicious cycle observed in osteolytic disease occurs also in osteoblastic metastases, and in addition cancer cells produce osteoblast-stimulating factors. Cancers with bone metastases often include both osteolytic and osteoblastic lesions. Our aim was to establish in vitro cell culture models to study the effects of cancer therapeutics on osteoblast and osteoclast differentiation and activity. In the osteoclast differentiation assay, human osteoclast precursor cells (Lonza) were cultured on bovine bone slices for 7 days. Denosumab was added in the cultures at day 0, and tartrate-resistant acid phosphatase isoform 5b (TRACP 5b) activity was measured from the culture medium collected at day 7. Osteoclast activity was studied by allowing osteoclasts resorb bone after 7 days’ maturation period for additional 3 days in the presence of odanacatib. The amount of C-terminal cross-linked telopeptides of type I collagen (CTX-I) was measured in the culture medium collected at day 10 to quantitate osteoclast activity. Denosumab and odanacatib showed strong concentration dependent inhibition of osteoclast differentiation and activity, respectively. A mouse osteoblast progenitor cell line KS483 (Pharmatest Services) was used to study differentiation and activity of osteoblasts with test compounds bone morphogenetic protein 2 (BMP-2) and estradiol (E2). In the osteoblast differentiation assay, the activity of cellular alkaline phosphatase (ALP), a marker of osteoblast differentiation, was measured at day 8. In the osteoblast activity assay, the cells were cultured for 13 days. N-terminal propeptide of type I procollagen (PINP) secreted into the culture medium was determined at day 11 to indicate the effects on organic bone formation and calcium deposition was determined at the end of the study as a marker of inorganic bone formation. BMP-2 and E2 stimulated osteoblast differentiation and activity indicated by the increase in ALP activity, PINP and calcium levels. We conclude that these culture systems can be used for studying the effects of cancer therapeutics and identifying new potential compounds affecting the disease process of bone metastases with different mechanisms of action. Citation Format: Jenni H. Mäki-Jouppila, Mervi Ristola, Jukka Rissanen, Katja Fagerlund. In vitro assays for investigating the effects of cancer therapeutics on bone [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2920.

A facile method to fabricate multifunctional polyvinyl alcohol mineralized hydrogels with high strength and adaptable shape

AbstractHydrogel‐based materials are widely used in many fields, but most of them compared to tendons with the same water content do not exhibit high toughness, strength or fatigue resistance, which limits their application. The Hofmeister effect can adjust the mechanical properties of hydrogels by ions affecting the aggregation of polymer chains. Herein, we prepared a bioactivated hydrogel through simply mixing polyvinyl alcohol (PVA) and Na2CO3 aqueous solutions. PVA chains are aggregated by strong hydrogen bonds between CO32− and OH, at which stage the hydrogel is soft and easy to shape. Further salting out promotes the formation of crystal microphase of PVA chain, resulting in high mechanical strength and excellent toughness. The existence of Na2CO3 endow the hydrogel with conductivity, exhibits high and stable sensitivity in strain sensing, and could be used to monitor human actions. On the basis of this method, Ca2+ was added to prepare mineralized PVA hydrogels, which had high stability and long‐term swelling resistance in different ionic solutions. In vitro cell experiment, hydrogel had obvious effect of promoting bone cell proliferation and calcium deposition. This work provides a facile and feasible method for preparing bionic hydrogels with high strength, toughness, and adaptable shape.

Effects of Menaquinone-7 on the Bone Health of Growing Rats under Calcium Restriction: New Insights from Microbiome-Metabolomics.

Insufficient calcium intake during growth is a global public health concern. The aim of this study was to investigate the effects of dietary menaquinone-7 (MK-7) on bone accrual in growing Sprague-Dawley rats under calcium restriction. Following 13 weeks of treatment, various bone quality parameters, including microarchitecture, were measured. Fecal and cecal samples were subjected to microbiome (16S rRNA gene sequencing) analyses, while metabolomics analysis of the cecum and humerus samples was analyzed based on UHPLC-Q/TOF-MS. We found that calcium deficiency diminished the richness of the microbiome and disrupted microbiome composition, accompanied by an elevation in the relative abundance of Parasutterella. Furthermore, calcium insufficiency escalated the level of isovaleric acid and modified the metabolic profiles. MK-7 supplementation significantly increased the cortical thickness, cortical bone area, and the calcium content of the femur. Apart from improving bone calcium deposition and diminishing bone resorption, the mechanisms underlying the beneficial effects of MK on bone quality also involve the modulation of the host's metabolic pathways and the composition of gut microbiota. The gut-bone axis holds promise as an efficacious target for ameliorating calcium deficiency in children's bone quality, and MK-7 is a promising dietary supplement from this perspective.

Biofunctionalization with Cissus quadrangularis phytobioactives accentuates Nano-Hydroxyapatite based ceramic Nano-Cement for Neo-Bone formation in critical sized bone defect

Developing biofunctionalized ceramic bone substitutes with phytobioactives for their sustained delivery is highly desired to enhance the osteo-active potential of ceramic bone substitutes, reduce the systemic toxicity of synthetic drugs, and increase the bioavailability of phytobioactives. The present work highlights the local delivery of phytobioactives of Cissus quadrangularis (CQ) through nano-hydroxyapatite (nHAP) based ceramic nano-cement. The phytoconstituent profiling represented the optimized CQ fraction to be rich in osteogenic polyphenols and flavonoids like quercetin, resveratrol, and their glucosides. Further, CQ phytobioactives-based formulation was biocompatible, increased bone formation, calcium deposition, proliferation, and migration of cells with simultaneous alleviation of cellular oxidative stress. In the in vivo critical-sized bone defect model, enhanced formation of highly mineralized tissue (BV mm3) in CQ phytobioactives functionalized nano-cement (10.5 ± 2 mm3) were observed compared to the control group (6.5 ± 1.2 mm3). Moreover, the addition of CQ phytobioactives to the bone nano-cement increased the fractional bone volume (BV/TV%) to 21 ± 4.2% compared to 13.1 ± 2.5% in non-functionalized nano-cement. The results demonstrated nHAP-based nano-cement as a carrier for phytobioactives which could be a promising approach for neo-bone formation in different bone defect conditions.

Vitamin K2: known and unknown. Modern view: opportunities and prospects

Currently vitamin K2 is one of the most popular micronutrients among both researchers and practitioners. In addition to its well-known role in the synthesis of coagulation factors, vitamin K2 regulates the deposition of calcium in bone and soft tissues, protecting against the development of osteoporosis and vascular calcification. In recent years, more and more data have been accumulated on its participation in the regulation of key physiological and pathological processes in the body, such as cell division and differentiation, carbohydrate metabolism, inflammation, oxidative stress, etc. In this review, we analyze the sources of vitamin K2, the mechanisms of its action and influence on metabolism.

ECM-inspired 3D printed polyetherimide scaffold with Arg-Gly-Asp peptides for the improvement of bioactivity and osteogenic differentiation of osteoblasts

High-performance polymers, such as polyetherimide (PEI), are promising bone biomaterials that meet the mechanical demands of bone defect repair. To achieve better therapeutic outcomes, the osteoinduction of high-performance polymers requires further improvement. In this study, the fused deposition modeling (FDM) 3D printing method was applied to fabricate orthogonal porous PEI scaffolds. Inspired by the simulation of the extracellular matrix (ECM), The polydopamine (PDA) and Arg-Gly-Asp (RGD) peptides were applied to construct an osteogenic microenvironment on PEI/PDA/RGD scaffold. The characterization, bioactivity, and osteogenic differentiation of the scaffolds were systematically investigated. The mechanical properties of the PEI/PDA/RGD scaffold were similar to those of bone tissues with favorable hydrophilicity and no biotoxicity. The adhesion, proliferation, extracellular bone matrix formation, calcium deposition, and alkaline phosphatase (ALP) vitality of MC3T3-E1 osteoblasts was higher in the PEI/PDA/RGD scaffold compared with other scaffolds. The PEI/PDA/RGD scaffold promoted the osteogenic differentiation of MC3T3-E1 osteoblasts by upregulating their gene expression of osteopontin (OPN), runt-related transcription factor 2 (RUNX-2), bone morphogenetic protein (BMP-2), osteocalcin (OCN), ALP, and especially type I collagen (COL-1). The PEI/PDA/RGD scaffold fabricated in this study is a promising bone biomaterial with appropriate mechanical properties and ideal osteogenic microenvironment, which has potential application in the field of bone defect repair. The construction of osteogenic microenvironment on 3D printed porous PEI scaffold could broaden the application of polyetherimide in bone biomaterials.

Enhanced Osteogenic Potential of Phosphonated-Siloxane Hydrogel Scaffolds.

In a material-guided approach, instructive scaffolds that leverage potent chemistries may efficiently promote bone regeneration. A siloxane macromer has been previously shown to impart osteoinductivity and bioactivity when included in poly(ethylene glycol) diacrylate (PEG-DA) hydrogel scaffolds. Herein, phosphonated-siloxane macromers were evaluated for enhancing the osteogenic potential of siloxane-containing PEG-DA scaffolds. Two macromers were prepared with different phosphonate pendant group concentrations, poly(diethyl(2-(propylthio)ethyl)phosphonate methylsiloxane) diacrylate (PPMS-DA) and 25%-phosphonated analogue (PPMS-DA 25%). Macroporous, templated scaffolds were prepared by cross-linking these macromers with PEG-DA at varying mol % (15:85, 30:70, and 45:55 PPMS-DA to PEG-DA; 30:70 PPMS-DA 25% to PEG-DA). Other scaffolds were also prepared by combining PEG-DA with PDMS-MA (i.e., no phosphonate) or with vinyl phosphonate (i.e., no siloxane). Scaffold material properties were thoroughly assessed, including pore morphology, hydrophobicity, swelling, modulus, and bioactivity. Scaffolds were cultured with human bone marrow-derived mesenchymal stem cells (normal media) and calcium deposition and protein expression were assessed at 14 and 28 days.

Fermentation Improves Calcium Bioavailability in Moringa oleifera leaves and Prevents Bone Loss in Calcium-deficient Rats.

Nowadays, there is an increasing demand of healthier plant calcium supplements. Moringa oleifera leaves (MOL) are rich in calcium and thus are promising candidates for developing efficient calcium supplements. Here, using fermentation‐based approaches, we developed a Moringa oleifera leaf ferment (MOLF), which contents higher levels of calcium. The therapeutic potential of the MOLF was also examined both in vitro and in vivo. Nine lactic acid bacteria and four yeasts were tested for better fermentation of MOL. Calcium‐deficient rats were used for evaluating the therapeutic effects of MOLF. The results of liquid fermentation showed that the mixture of Lactobacillus reuteri, Lactobacillus acidophilus , and Candida utilis elevated the content of MOL calcium most strikingly, with the content of calcium increased nearly 2.4‐fold (from 2.08% to 4.90%). The resulting MOLF was then subjected to cell experiments and animal experiments. The results showed that calcium absorption in Caco‐2 cells in MOLF group was higher than that in CaCl2 group significantly. Interestingly, in calcium‐deficient rats, MOLF treatment significantly increased the thickness of cortical bone, rat body weight, wet weight of the femur, and the femur bone density, whereas it decreased osteoclast numbers. These results indicate that microbial fermentation increased calcium bioavailability of MOL, promote the growth and development of calcium‐deficient rats, bone calcium deposition, and bone growth; enhance bone strength; reduce bone resorption; and prevent calcium deficiency.

Herring egg phosphopeptides as calcium carriers for improving calcium absorption and bone microarchitecture in vivo.

Phosphorylation may enhance the functional properties of proteins/peptides. Herring egg phosphopeptides (HEPPs) have been found to be more effective than the non-phosphorylated variant in calcium-binding activities due to the introduced phosphate groups. However, whether HEPPs as calcium carriers will be superior to herring egg peptides (HEPs) in improving calcium bioavailability in vivo, for the equivalent calcium intake prerequisite, remains to be clarified. This study aimed to evaluate the effect of HEPPs-calcium complex and HEPs-calcium complex on calcium absorption and bioavailability in calcium-deficient mice. Results showed that the remarkably lower calcium absorption and bone calcium deposition induced by long-term calcium deficiency were accompanied by deterioration of the trabecular bone microarchitecture (P < 0.05). The HEPPs-Ca supplements significantly improved the apparent calcium absorption, increased the serum calcium level, decreased the alkaline phosphatase activity, strengthened the bone biomechanical property, and increased bone volume/tissue volume (BV/TV) and trabecular number (Tb·N) in calcium-deficient mice (P < 0.05), as determined by micro-computed tomography (micro-CT) assay. The effect of HEPPs-Ca on calcium absorption and bioavailability was comparable to that of CPPs-Ca, but better than that of HEPs-Ca and CaCO3. This study brings new insights into the potential of HEPPs as an alternative to CPPs for use in calcium supplements.

Effects of Endothelial Progenitor Cells on Vascularization and Osteogenesis of Tissue-engineered Bones in Beagle Dogs

Objective The explore the effects of endothelial progenitor cells(EPCs)on vascularization and osteogenesis of tissue-engineered bones in Beagle dogs.Methods Bone marrow mesenchymal stem cells(BMSCs)and EPCs from bone marrow of Beagle dogs were isolated,cultured,and expanded and then seeded in β-tricalcium phosphate(TCP)scaffolds. The cell scaffold complexes(EPCs/ BMSCs/TCP group and BMSCs/TCP group)and the blank TCP scaffold were transplanted into the limb muscles of Beagle dogs,respectively. The relative CT values were calculated in the 3rd and 6th month through CT scan after operation. The vascularization and the osteogenesis were detected 6 months after operation by histological examination.Results Three months after the surgery,the relative CT value in the EPCs/BMSCs/TCP group was(366.67±19.51)HU,significantly higher than that[(163.00±30.81)HU] in the BMSCs/TCP group(t=2.10,P=0.0006);6 months after surgery,the relative CT value in the EPCs/BMSCs/TCP group was(553.34±26.86)HU,which was also significantly higher than that[(241.34±21.57)HU] in the BMSCs/TCP group(t=2.11,P=0.0006). The relative CT values at 6 months after operation were significantly higher than those at 3 months after operation in both BMSCs/TCP group(t=2.10,P=0.0255)and EPCs/BMSCs/TCP group(t=2.10,P=0.0006). Six months after the operation,HE staining showed no bone formation or calcium deposition in the blank TCP group,and osteoblasts,mature bone trabeculae,and calcium deposition were observed in EPCs/BMSCs/TCP group and BMSCs/TCP group. Immunohistochemical staining showed that the number of peripheral,central,and whole vessels in the EPCs/BMSCs/TCP group was 21.67±1.45,23.33±2.60,and 45.00±1.16,which were significantly higher than those in the BMSCs/TCP group[8.67±0.88(t=2.07,P=0.0016),9.33±0.67(t=2.07,P=0.0065),and 18.00±1.00(t=2.07,P=0.001),respectively]. The number of vessels was not significantly different between the BMSCs/TCP group and the blank TCP group(18.00±1.00 vs. 16.67±2.40;t=2.07,P=0.636). The osteogenic area of the EPCs/BMSCs/TCP group was(1 322 000±141 300)pixel,significantly higher than that of the BMSCs/TCP group[(874 900±49 430)pixel;t=2.10,P=0.04]. BMSCs/TCP group showed significantly higher bone area in the peripheral area than in the central region[(170 000±42 320)pixel vs.(613 900±90 290)pixel;t=2.10,P=0.02];in contrast,there was no statistically significant difference in bone area between the peripheral region and the central region in the EPCs/BMSCs/TCP group[(376 400±20 160)pixel vs.(310 400±6917)pixel;t=2.10,P=0.07].Conclusion EPCs as seed cells combined with BMSCs can promote vascularization and osteogenesis of tissue-engineered bone in Beagle dogs.

Osteoinduction within BMP-2 transduced muscle tissue fragments with and without a fascia layer: implications for bone tissue engineering.

Bone can be engineered in vivo by implantation of gene-activated muscle tissue fragments. This expedited approach may be further improved by use of muscle tissue with attached fascia. The aim of this in vitro study was to provide an in depth comparison of the osteogenic differentiation capacity of muscle alone and muscle with fascia after BMP-2 transduction. Skeletal muscle tissue from rats was cut into pieces with and without a fascia layer on the surface. Adenoviral BMP-2 or GFP vectors were used for transduction. Osteogenic differentiation within the tissue fragments was evaluated and compared by qRT-PCR, alizarin red S staining, histomorphometry and immunohistology. Transduction efficiency and level of transgene expression were higher for muscle with fascia than muscle alone. Transduction with BMP-2 led to a significant upregulation of bone marker genes, proteins, and calcium deposition in both groups. Interestingly, histological evaluation revealed that osteoinduction did not occur within the fascia layer itself. The upregulation of bone marker genes in muscle with fascia was significantly lower after 2 weeks but similar after 4 weeks of in vitro culture in comparison to muscle alone. The fascia layer led to higher transduction efficiency and enhanced BMP-2 expression. Despite fascia's lower capacity for osteogenic differentiation, muscle implants may benefit from the fascia layer by the improved ability to deliver BMP-2. The presented data may contribute to the development of a novel, cost-effective, single-surgery bone engineering technology and encourage the evaluation of the osteoregenerative potential of muscle with fascia in an animal model.

Nanostructured TiO₂ Surfaces Promote Human Bone Marrow Mesenchymal Stem Cells Differentiation to Osteoblasts.

Micro- and nano-patterning/modification are emerging strategies to improve surfaces properties that may influence critically cells adherence and differentiation. Aim of this work was to study the in vitro biological reactivity of human bone marrow mesenchymal stem cells (hBMSCs) to a nanostructured titanium dioxide (TiO2) surface in comparison to a coverglass (Glass) in two different culture conditions: with (osteogenic medium (OM)) and without (proliferative medium (PM)) osteogenic factors. To evaluate cell adhesion, hBMSCs phosphorylated focal adhesion kinase (pFAK) foci were analyzed by confocal laser scanning microscopy (CLSM) at 24 h: the TiO2 surface showed a higher number of pFAK foci with respect to Glass. The hBMSCs differentiation to osteoblasts was evaluated in both PM and OM culture conditions by enzyme-linked immunosorbent assay (ELISA), CLSM and real-time quantitative reverse transcription PCR (qRT-PCR) at 28 days. In comparison with Glass, TiO2 surface in combination with OM conditions increased the content of extracellular bone proteins, calcium deposition and alkaline phosphatase activity. The qRT-PCR analysis revealed, both in PM and OM, that TiO2 surface increased at seven and 28 days the expression of osteogenic genes. All together, these results demonstrate the capability of TiO2 nanostructured surface to promote hBMSCs osteoblast differentiation and its potentiality in biomedical applications.

JiangTang XiaoKe granule attenuates cathepsin K expression and improves IGF-1 expression in the bone of high fat diet induced KK-Ay diabetic mice

AimTo assess the beneficial effects of JiangTang XiaoKe (JTXK) granule on the bone metabolism in high fat diet (HFD) fed KK-Ay diabetic mice. Materials and methodsThe KK-Ay mice were used as a diabetic model, while C57BL/6 mice were utilized as the non-diabetic control. The left tibia was used for determining bone mineral density (BMD) and bone ash coefficient. The HE and alizarin red S staining of femur were employed to evaluate bone pathology and calcium deposition. The expressions of alkaline phosphatase (ALP), insulin growth factor 1 (IGF-1) and cathepsin K were assessed by western blotting and immunohistochemical staining. Key findingsJTXK granule significantly improved the bone ash coefficient, the distribution of trabecular bone and the calcification nodules deposition in KK-Ay mice with diabetes. IGF-1 and ALP expressions were significantly decreased, and cathepsin K expression was dramatically increased in the HFD fed KK-Ay diabetic model mice, which can be reversed by JTXK granule treatment. JTXK granule at medium or high dosage was more efficient in improving diabetic bone quality when compared with that in mice with a low dosage. However, the BMD values in each group of KK-Ay diabetic mice were not significantly different. SignificanceWe demonstrate that cathepsin K expression is increased in KK-Ay diabetic mouse model. JTXK granule treatment inhibits osteoclastic bone resorption and promotes the new bone formation by decreasing cathepsin K activity and increasing IGF-1 and ALP levels. These changes may contribute to the increase of bone strength and thus reducing the risk of bone fractures.

Bone Is a Major Target of PTH/PTHrP Receptor Signaling in Regulation of Fetal Blood Calcium Homeostasis.

The blood calcium concentration during fetal life is tightly regulated within a narrow range by highly interactive homeostatic mechanisms that include transport of calcium across the placenta and fluxes in and out of bone; the mechanisms of this regulation are poorly understood. Our findings that endochondral bone-specific PTH/PTHrP receptor (PPR) knockout (KO) mice showed significant reduction of fetal blood calcium concentration compared with that of control littermates at embryonic day 18.5 led us to focus on bone as a possibly major determinant of fetal calcium homeostasis. We found that the fetal calcium concentration of Runx2 KO mice was significantly higher than that of control littermates, suggesting that calcium flux into bone had a considerable influence on the circulating calcium concentration. Moreover, Runx2:PTH double mutant fetuses showed calcium levels similar to those of Runx2 KO mice, suggesting that part of the fetal hypocalcemia in PTH KO mice was caused by the increment of the mineralized bone mass allowed by the formation of osteoblasts. Finally, Rank:PTH double mutant mice had a blood calcium concentration even lower than that of the either Rank KO or PTH KO mice alone at embryonic day 18.5. These observations in our genetic models suggest that PTH/PTHrP receptor signaling in bones has a significant role of the regulation of fetal blood calcium concentration and that both placental transport and osteoclast activation contribute to PTH's hypercalcemic action. They also show that PTH-independent deposition of calcium in bone is the major controller of fetal blood calcium level.

Calcitonin, the forgotten hormone: does it deserve to be forgotten?

Calcitonin is a 32 amino acid hormone secreted by the C-cells of the thyroid gland. Calcitonin has been preserved during the transition from ocean-based life to land dwellers and is phylogenetically older than parathyroid hormone. Calcitonin secretion is stimulated by increases in the serum calcium concentration and calcitonin protects against the development of hypercalcemia. Calcitonin is also stimulated by gastrointestinal hormones such as gastrin. This has led to the unproven hypothesis that postprandial calcitonin stimulation could play a role in the deposition of calcium and phosphate in bone after feeding. However, no bone or other abnormalities have been described in states of calcitonin deficiency or excess except for diarrhea in a few patients with medullary thyroid carcinoma. Calcitonin is known to stimulate renal 1,25 (OH)2 vitamin D (1,25D) production at a site in the proximal tubule different from parathyroid hormone and hypophosphatemia. During pregnancy and lactation, both calcitonin and 1,25D are increased. The increases in calcitonin and 1,25D may be important in the transfer of maternal calcium to the fetus/infant and in the prevention and recovery of maternal bone loss. Calcitonin has an immediate effect on decreasing osteoclast activity and has been used for treatment of hypercalcemia. Recent studies in the calcitonin gene knockout mouse have shown increases in bone mass and bone formation. This last result together with the presence of calcitonin receptors on the osteocyte suggests that calcitonin could possibly affect osteocyte products which affect bone formation. In summary, a precise role for calcitonin remains elusive more than 50 years after its discovery.

Growth responses of native chicken Sentul G-3 on diet containing high rice-bran supplemented with phytase enzyme and ZnO

This study was conducted to determine the effect of phytase enzymes and ZnO supplementation on the performance of native chicken Sentul-G3 fed high rice-bran diet. Two hundred and seventy day old chicks (DOC) native chicken Sentul-G3 from three different hatcheries were used in this study. Factorial randomized block design (3 x 3) was applied in this study. The first factor was the enzyme phytase supplementation levels (0; 1000; 2000 U/kg), the second factor was the level of supplementation of ZnO (0; 1.5; 3.2 g/kg), so that there are nine treatment given, namely R1 = 50% commercial diet : 50% rice bran; R2 = R1 + 1.5 g ZnO/kg; R3 = R1 + 3.2 g ZnO/kg; R4 = R1 + phytase enzyme 1000 U/kg; R5 = R1 + (phytase enzyme 1000 U/kg + 1.5 g ZnO/kg); R6 = R1 + (phytase enzyme 1000 U/kg + 3.2 g ZnO/kg); R7 = R1 + phytase enzyme 2000 U/kg; R8 = R1 + (phytase enzyme 2000 U/kg + 1.5 g ZnO/kg); R9 = R1 + (phytase enzyme 2000 U/kg + 3.2 g ZnO/kg). Each experimental unit consisted of 6 head unsexed native chicken Sentul-G3. The experimental diet was fed for 10 weeks. The variables measured were body weight, body weight gain, feed intake, feed conversion ratio, mortality, mineral deposition of Ca, P, Zn in the tibia bone, alkaline phosfatase enzyme activity in serum. Results showed that there was significant interaction (P 0.05) between phytase enzyme and ZnO supplementation on feed intake, mortality, alkaline phosphatase enzyme activity in serum, and deposition of calcium and phosphorus in the tibia bone. It was concluded that supplementation of phytase enzyme and ZnO were not able to increase the growth of native chicken Sentul-G3 on fed diet containing high rice bran.

Bone morphogenetic protein 2 and decorin expression in old fracture fragments and surrounding tissues.

Bone morphogenetic protein 2 (BMP-2) can promote fracture healing. Although the complex role BMP-2 in bone formation is increasingly understood, the role of endogenous BMP-2 in nonunion remains unclear. Decorin (DCN) can promote the formation of bone matrix and calcium deposition to control bone morphogenesis. In this study, tissue composition and expression of BMP-2 and DCN were detected in different parts of old fracture zones to explore inherent anti-fibrotic ability and osteogenesis. Twenty-three patients were selected, including eight cases of delayed union and 15 cases of nonunion. Average duration of delayed union or nonunion was 15 months. Fracture fragments and surrounding tissues, including bone grafts, marrow cavity contents, and sticking scars, were categorically sampled during surgery. Through observation and histological testing, component comparisons were made between fracture fragments and surrounding tissue. The expression levels of DCN and BMP-2 in different tissues were detected by immunohistochemical staining and real-time polymerase chain reaction. The expression of DCN and BMP- 2 in different parts of the nonunion area showed that, compared with bone graft and marrow cavity contents, sticking scars had the highest expression of BMP-2. Compared with the marrow cavity contents and sticking scars, bone grafts had the highest expression of DCN. The low antifibrotic and osteogenic activity of the nonunion area was associated with non-co-expression of BMP-2 and DCN. Therefore, the co-injection of osteogenic factor BMP and DCN into the nonunion area can improve the induction of bone formation and enhance the conversion of the old scar, thereby achieving better nonunion treatment.

Serum 1,25-dihydroxyvitamin D and calcium intake affect rates of bone calcium deposition during pregnancy and the early postpartum period

Factors affecting bone calcium deposition across pregnancy and lactation are not well characterized. The impact of maternal age, calcium intake, race-ethnicity, and vitamin D status on the rate of bone calcium deposition (VO+) was assessed across pregnancy and lactation. Stable calcium isotopes were given to 46 women at pre- or early pregnancy (trimester 1), late pregnancy (trimester 3), and 3-10 wk postpartum. Three cohorts were included: 23 adolescents from Baltimore (MD), aged 16.5 ± 1.4 y (mean ± SD; Baltimore cohort); 13 adults from California, aged 29.5 ± 2.6 y (California cohort); and 10 adults from Brazil, aged 30.4 ± 4.0 y (Brazil cohort). The total exchangeable calcium pool, VO+, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D [1,25(OH)₂D], parathyroid hormone, and calcium intake were evaluated. At trimester 3, inverse associations between 1,25(OH)₂D and VO+ were evident in the Baltimore (P = 0.059) and Brazil (P = 0.008) cohorts and in the whole group (P = 0.029); calcium intake was not a significant determinant of VO+ in any group during pregnancy. At postpartum, a significant positive association was evident between VO+ and calcium intake (P ≤ 0.002) and between VO+ and African ethnicity (P ≤ 0.004) in the whole group and within the Baltimore and Brazil cohorts. Elevated 1,25(OH)₂D was associated with decreased rates of bone calcium deposition during late pregnancy, a finding that was particularly evident in pregnant adolescents and adult women with low calcium intakes. Higher dietary calcium intakes and African ethnicity were associated with elevated rates of bone calcium deposition in the postpartum period.

The enhancement of osteogenesis through the use of dental pulp pluripotent stem cells in 3D

The potential for osteogenic differentiation of dental pulp mesenchymal stem cells (DPMSCs) in vitro and in vivo has been well documented in a variety of studies. Previously, we obtained a population of cells from human dental pulp called dental pulp pluripotent stem cells (DPPSCs) that could differentiate into mesodermal, ectodermal and endodermal progenies. We compared the osteogenic capacity of DPPSCs and DPMSCs that had been isolated from the same donors (N=5) and cultivated in the same osteogenic medium in 3D (three dimensions) Cell Carrier glass scaffolds. We also compared the architecture of bone-like tissue obtained from DPPSCs and human maxillary bone tissue. Differentiation was evaluated by scanning electron microscopy, whereas the expression of bone markers such as ALP, Osteocalcin, COLL1 and Osteonectin was investigated by quantitative real time polymerase chain reaction (qRT-PCR). We also used calcium quantification, Alizarin red staining and alkaline phosphatase (ALP) activity to compare the two cell types. New bone tissue formed by DPPSCs was in perfect continuity with the trabecular host bone structure, and the restored bone network demonstrated high interconnectivity. Significant differences between DPPSCs and DPMSCs were observed for the expression of bone markers, calcium deposition and ALP activity during osteogenic differentiation; these criteria were higher for DPPSCs than DPMSCs. Both DPPSCs and differentiated tissue showed normal chromosomal dosage after being cultured in vitro and analysed using short-chromosome genomic hybridisation (short-CGH). This study demonstrates the stability and potential for the use of DPPSCs in bone tissue engineering applications.