Higher Bone Formation Rate Research Articles

Inhibition of RANKL improves the skeletal phenotype of adenine-induced chronic kidney disease in mice.

Skeletal fragility and high fracture rates are common in CKD. A key component of bone loss in CKD with secondary hyperparathyroidism is high bone turnover and cortical bone deterioration through both cortical porosity and cortical thinning. We hypothesized that RANKL drives high bone resorption within cortical bone leading to the development of cortical porosity in CKD (study 1) and that systemic inhibition of RANKL would mitigate the skeletal phenotype of CKD (study 2). In study 1, we assessed the skeletal properties of male and female Dmp1-cre RANKLfl/fl (cKO) and control genotype (Ranklfl/fl; Con) mice after 10wk of adenine-induced CKD (AD; 0.2% dietary adenine). All AD mice regardless of sex or genotype had elevated blood urea nitrogen and high PTH. Con AD mice in both sexes had cortical porosity and lower cortical thickness as well as high osteoclast-covered trabecular surfaces and higher bone formation rate. cKO mice had preserved cortical bone microarchitecture despite high circulating PTH as well as no CKD-induced increases in osteoclasts. In study 2, male mice with established AD CKD were either given a single injection of an anti-RANKL antibody (5mg/kg) 8wk post-induction of CKD or subjected to 3×/wk dosing with risedronate (1.2μg/kg) for 4wk. Anti-RANKL treatment significantly reduced bone formation rate as well as osteoclast surfaces at both trabecular and cortical pore surfaces; risedronate treatment had little effect on these bone parameters. In conclusion, these studies demonstrate that bone-specific RANKL is critical for the development of high bone formation/high osteoclasts and cortical bone loss in CKD with high PTH. Additionally, systemic anti-RANKL ligand therapy in established CKD may help prevent the propagation of cortical bone loss via suppression of bone turnover.

Composite bone graft of CaO-MgO-SiO2 glass-ceramics and CaSO4 ceramics for boosting bone formation rate.

This study develops a composite bone graft of CaO-MgO-SiO2 glass-ceramic and CaSO4 [abbreviated as (CMS)3-x(CS)x] via the sponge replication technique with weight fractions of x = 0, 1, 1.5, 2, and 3. The (CMS)1.5(CS)1.5 composite displays a superior degradability and, a suitable compressive strength of ∼3 MPa, and excellent cell proliferation and differentiation. The in vivo rat femur test in the hybrid-pore (CMS)1.5(CS)1.5 composite granules achieves a higher rate of bone formation, which is ∼2.7 times better than that of the commercial HAP/β-TCP at 12 weeks. Improved expressions of osteocyte and mature osteocyte marker genes, namely (Spp1, Dmp1, and Fgf23), were observed in the (CMS)1.5(CS)1.5 group, indicating a faster differentiation into mature bone tissue. The ions release of (CMS)1.5(CS)1.5 through the ERK1/2 signaling pathway promotes osteogenic differentiation. The high bone generation rate can be attributed to faster active ions release and modified surface topography. This work highlights an excellent bone graft candidate for clinical applications in orthopedic surgery.

Inclusion of calcium phosphate does not further improve in vitro and in vivo osteogenesis in a novel, highly biocompatible, mechanically stable and 3D printable polymer

At a time of unpredictable challenges for health, one trend is certain: there is an exceedingly high demand for functional implants, particularly bone grafts. This has encouraged the emergence of bone tissue engineering substitutes as an alternative method to conventional bone grafts. However, the current approaches in the field face several limitations that have prevented the ultimate translation into clinical settings. As a result, many attempts have been made to fabricate synthetic bone implants that can offer suitable biological and mechanical properties.Light curable methacrylate-based polymers have ideal properties for bone repair. These materials are also suitable for 3D printing which can be applicable for restoration of both function and aesthetics. The main objective of this research was to investigate the role of calcium phosphate (CaP) incorporation in a mechanically stable, biologically functional and 3D printable polymer for the reconstruction of complex craniofacial defects. The experimental work initially involved the synthesis of (((((((((((3R,3aR,6S,6aR)- hexahydrofuro[3,2-b]furan-3,6-diyl)bis(oxy))bis(ethane-2,1- 48 diyl))bis(oxy))bis(carbonyl))bis(azanediyl))bis(3,3,5-trimethylcyclohexane-5,1- 49 diyl))bis(azanediyl))bis(carbonyl))bis(oxy))bis(ethane-2,1-diyl) bis(2-methylacrylate) referred to as CSMA and fabrication of composite discs via a Digital Light Printing (DLP) method. The flow behaviour of the polymer as a function of CaP addition, surface remineralisation potential, in vitro cell culture, using MC3T3 and Adipose-Derived Mesenchymal Stem Cells (ADSCs) and ex ovo angiogenic response was assessed. Finally, in vivo studies were carried out to investigate neo-bone formation at 4- and 8-weeks post-implantation. Quantitative micro-CT and histological evaluation did not show a higher rate of bone formation in CaP filled CSMA composites compared to CSMA itself. Therefore, such polymeric systems hold promising features by allowing more flexibility in designing a 3D printed scaffold targeted at the reconstruction of maxillofacial defects.

Hindlimb unloading causes regional loading-dependent changes in osteocyte inflammatory cytokines that are modulated by exogenous irisin treatment

Disuse-induced bone loss is characterized by alterations in bone turnover. Accruing evidence suggests that osteocytes respond to inflammation and express and/or release pro-inflammatory cytokines; however, it remains largely unknown whether osteocyte inflammatory proteins are influenced by disuse. The goals of this project were (1) to assess osteocyte pro-inflammatory cytokines in the unloaded hindlimb and loaded forelimb of hindlimb unloaded rats, (2) to examine the impact of exogenous irisin during hindlimb unloading (HU). Male Sprague Dawley rats (8 weeks old, n = 6/group) were divided into ambulatory control, HU, and HU with irisin (HU + Ir, 3×/week). Lower cancellous bone volume, higher osteoclast surfaces (OcS), and lower bone formation rate (BFR) were present at the hindlimb and 4th lumbar vertebrae in the HU group while the proximal humerus of HU rats exhibited no differences in bone volume, but higher BFR and lower OcS vs. Con. Osteocyte tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), RANKL, and sclerostin were elevated in the cancellous bone of the distal femur of HU rats vs. Con, but lower at the proximal humerus in HU rats vs. Con. Exogenous irisin treatment increased BFR, and lowered OcS and osteocyte TNF-α, IL-17, RANKL, and sclerostin in the unloaded hindlimb of HU + Ir rats while having minimal changes in the humerus. In conclusion, there are site-specific and loading-specific alterations in osteocyte pro-inflammatory cytokines and bone turnover with the HU model of disuse bone loss, indicating a potential mechanosensory impact of osteocyte TNF-α and IL-17. Additionally, exogenous irisin significantly reduced the pro-inflammatory status of the unloaded hindlimb.

Association of parathormone and alkaline phosphatase with bone turnover and mineralization in children with CKD on dialysis: effect of age, gender, and race.

Studies investigating bone histology in children with chronic kidney disease (CKD) are scarce. Forty-two patients, mean age 11.3 ± 4.3years with stage 5 CKD on dialysis, underwent double tetracycline labeling bone biopsy and the relationship between clinical features, biochemical markers, and bone densitometry (DXA) was investigated. Low bone turnover was present in 59% of patients, abnormal mineralization in 29%, and low bone volume in 7%. Higher bone formation rate was found in non-Caucasian patients, whereas abnormal mineralization occurred in older and shorter children. We found no impact of gender and etiology of renal disease in our population. Parathormone (PTH) and alkaline phosphatase (AP) showed positive associations with bone turnover. ROC curve analysis showed a fair performance of biomarkers to predict TMV status. PTH < 2 times ULN independently associated with low bone turnover (RR 5.62, 95% CI 1.01-31.24; p = 0.049), in a model adjusted for race, calcitriol dosage, and calcium. It was also associated with abnormal mineralization (RR 1.35, 95% CI 1.04-1.75; p = 0.025), in a model adjusted for BMD scores, AP, age, and calcitriol. PTH and AP significantly predicted turnover and mineralization defect, although with low specificity and sensitivity, reaching a maximum value of 64% and 67%, respectively. While PTH and AP were associated with turnover and mineralization, we recognize the limitation of their performance to clearly distinguish high from low/normal bone turnover and normal from abnormal mineralization. Our results reinforce the need to expand knowledge about renal osteodystrophy in pediatric population through prospective bone biopsy studies. Graphical abstract.

Histopathological features of condylar hyperplasia and condylar Osteochondroma: a comparison study

BackgroundBoth mandibular condylar hyperplasia and condylar osteochondroma can lead to maxillofacial skeletal asymmetry and malocclusion, although they exhibit different biological behavior. This study attempted to compare the histological features of mandibular condylar hyperplasia and condylar osteochondroma using hematoxylin-and-eosin (H&E) staining, and immunohistochemistry staining of PCNA and EXT1 with quantitative analysis method.ResultsThe H&E staining showed that condylar hyperplasia and condylar osteochondroma could be divided into four histological types and exhibited features of different endochondral ossification stages. There was evidence of a thicker cartilage cap in condylar osteochondroma as compared condylar hyperplasia (P = 0.018). The percentage of bone formation in condylar osteochondroma was larger than was found in condylar hyperplasia (P = 0.04). Immunohistochemical staining showed that PCNA was mainly located in the undifferentiated mesenchymal layer and the hypertrophic cartilage layer, and there were more PCNA positive cells in the condylar osteochondroma (P = 0.007). EXT1 was mainly expressed in the cartilage layer, and there was also a higher positive rate of EXT1 in condylar osteochondroma (P = 0.0366). The thicker cartilage cap, higher bone formation rate and higher PCNA positive rate indicated a higher rate of proliferative activity in condylar osteochondroma. The more significant positive rate of EXT1 in condylar osteochondroma implied differential biological characteristic as compared to condylar hyperplasia.ConclusionsThese features might be useful in histopathologically distinguishing condylar hyperplasia and osteochondroma.

Osteocalcin affects bone mineral and mechanical properties in female mice.

Osteocalcin is one of the most abundant noncollagenous proteins in bone. Phenotypes of osteocalcin knock-out mice (OC-/-) may vary on different backgrounds and with sex. Previous studies using adult female (OC-/-) mice on a mixed genetic background (129/B6) showed osteocalcin inhibited bone formation leading to weaker bone in wild-type (OC+/+). Yet on a pure (B6) genetic background male mice revealed osteocalcin improved fracture resistance and OC-/- bones were more prone to fracture. Osteocalcin is decreased with age and in some diseases (diabetes) where bone weakness is observed. The effect of osteocalcin in adult female bone from mice on a pure B6 background is unknown. We investigated differences in bone mineral properties and bone strength in female adult (6 months) (OC+/+) and (OC-/-) mice on a pure C57BL/6J background using Fourier Transform Infrared Imaging (FTIRI), micro-computed tomography (uCT), biomechanical measurements, histomorphometry and serum turnover markers (P1NP, CTX). Similar to female age matched mice on the (129/C57) background we found B6 OC-/- mice had a higher bone formation rate, no change in bone resorption, more immature mineral, decreased crystallinity and increased trabecular bone as compared to OC+/+. In contrast, the OC-/- mice on a pure B6 background had a lower bone mineral density, lower mineral to matrix ratio resulting in reduced stiffness and weaker bone strength. Our results demonstrate some properties of the OC-/- phenotype are dependent on genetic background. This may suggest that reduced osteocalcin may contribute to fracture and weaker bone in some groups of elderly and adults with diseases where osteocalcin is low.

P035 EXOGENOUS ADMINISTRATION OF IRISIN DURING CHRONIC TNBS-INDUCED GUT INFLAMMATION REVERSES INFLAMMATION-INDUCED ALTERATIONS IN BONE TURNOVER

A comorbidity of inflammatory bowel disease (IBD) is inflammation-induced bone loss characterized by elevated bone resorption and decreased bone formation. Fracture incidence is resultantly elevated. Using a TNBS rat model, we have found osteocytes, cells embedded in the bone matrix, have high TNF-α prevalence. Two proteins TNF-α regulates – RANKL, a driver of bone resorption, and sclerostin, an inhibitor of bone formation – were elevated concurrent with TNF-α. These alterations in osteocyte proteins correlated with changes in bone turnover. Irisin, a factor released during exercise, has been proposed to be a bone anabolic factor. We hypothesized exogenous irisin treatment during chronic IBD would exert anti-inflammatory actions improving IBD-associated bone outcomes. 2-month old, male, Sprague Dawley rats instilled rectally with TNBS/Vehicle solutions for 4-weeks. 1-week after TNBS initiation, irisin-treated rats were given bi-weekly irisin injections. Proximal tibia cancellous bone had high osteoclast surface (OcS) and low bone formation rate (BFR) in TNBS, but treatment with irisin resulted in 2-fold higher BFR and 51% lower OcS vs. TNBS alone. TNBS rats had high distal femur cancellous osteocytes positive for TNF-α, but irisin lowered TNF-α+ osteocytes by 6.6-fold. Additionally, RANKL+ and sclerostin+ osteocytes were high in TNBS, but were 2- 4-fold lower in irisin-treated TNBS animals, no different from vehicle-treated rats. Chronic IBD results in alterations in bone turnover leading to bone loss. Irisin treatment reversed the high OcS and low BFR seen in animals with chronic gut inflammation. Osteocyte TNF-α and the factors it regulates (RANKL and sclerostin) were lowered to levels no different than vehicle-treated rats indicating irisin’s actions as an anti-inflammatory agent. Irisin is a potential novel therapeutic treatment for IBD and associated inflammatory comorbidities including inflammation-induced bone loss.

Demineralized Xenogenic Dentin and Autogenous Bone as Onlay Grafts to Rabbit Tibia.

The present study was undertaken to evaluate the healing pattern of xenogenic demineralized dentin onlay grafts in comparison with autogenous bone grafts to the rabbit tibia. Eight 6-month-old New Zealand male rabbits were used in the experiments. Standardized sized dentin blocks from human premolars and similar autogenous bone blocks harvested from tibia were grafted as onlay blocks on each tibia (n = 8 × 2). All animals were killed after a healing period of 12 weeks. Healing was uneventful for all animals. In general, both the dentin and bone block grafts were fused to the bone, resorbed, and replaced by bone and connective tissue to a varying degree. Both types of grafts were still present after 12 weeks, on an average to approximately one third of the original sizes. Resorption cavities could be seen in the dentin with bone formation. Zones of osseous replacement resorption of the dentin could be noted. In both graft types, higher rate of bone formation was seen at the interface between graft and recipient site. Demineralized xenogenic dentin onlay grafts showed similar resorption characteristics as autogenous bone onlay grafts, being resorbed in a similar rate during 12 weeks. New bone formation occurred mainly in terms of replacement resorption in the interface between dentin/bone graft and native bone.

Vascular endothelial growth factor and biphasic calcium phosphate in the endosseous healing of femoral defects: An experimental rat study

Background/purposeThe presence of adequate bone volume is a critical factor in rehabilitative dentistry. Despite the use of many promising alloplasts, success in stimulating bone formation has been limited, mostly due to poor local biological response. Growth factors have been introduced to stimulate angiogenesis and new bone formation. This histologic and histomorphometric study aimed to evaluate the effect of vascular endothelial growth factor (VEGF) and a biphasic alloplastic graft material (BA) on the healing of endosseous defects in rats. Materials and methodsTwenty male Wistar rats were used. Two critical-sized bone defects were created in both the right and left femurs of each rat. Each defect was randomly assigned to be treated with VEGF, BA, or VEGF + BA, or to be left empty as a control. Half of the animals were sacrificed after 1 week, and the remaining half were sacrificed after 2 weeks. Inflammation, necrosis, and new bone areas were evaluated by means of histologic and histomorphometric analyses. ResultsCompared to the control group, defects treated with VEGF alone or in combination with BA showed higher rates of bone formation (33.10–46.60%) on Day 7. Additionally, VEGF significantly reduced inflammation and necrosis (P < 0.001). However, the differences were no longer discernable on Day 14. ConclusionVEGF makes a significant contribution to angiogenesis and osteogenesis in the early stages of bone defect healing, and its combination with an osteoconductive grafting material (BA) may further enhance new bone formation.

Room temperature housing results in premature cancellous bone loss in growing female mice: implications for the mouse as a preclinical model for age-related bone loss.

Room temperature housing (22°C) results in premature cancellous bone loss in female mice. The bone loss was prevented by housing mice at thermoneutral temperature (32°C). Thermogenesis differs markedly between mice and humans and mild cold stress induced by standard room temperature housing may introduce an unrecognized confounding variable into preclinical studies. Female mice are often used as preclinical models for osteoporosis but, in contrast to humans, mice exhibit cancellous bone loss during growth. Mice are routinely housed at room temperature (18-23°C), a strategy that exaggerates physiological differences in thermoregulation between mice (obligatory daily heterotherms) and humans (homeotherms). The purpose of this investigation was to assess whether housing female mice at thermoneutral (temperature range where the basal rate of energy production is at equilibrium with heat loss) alters bone growth, turnover and microarchitecture. Growing (4-week-old) female C57BL/6J and C3H/HeJ mice were housed at either 22 or 32°C for up to 18weeks. C57BL/6J mice housed at 22°C experienced a 62% cancellous bone loss from the distal femur metaphysis during the interval from 8 to 18weeks of age and lesser bone loss from the distal femur epiphysis, whereas cancellous and cortical bone mass in 32°C-housed mice were unchanged or increased. The impact of thermoneutral housing on cancellous bone was not limited to C57BL/6J mice as C3H/HeJ mice exhibited a similar skeletal response. The beneficial effects of thermoneutral housing on cancellous bone were associated with decreased Ucp1 gene expression in brown adipose tissue, increased bone marrow adiposity, higher rates of bone formation, higher expression levels of osteogenic genes and locally decreased bone resorption. Housing female mice at 22°C resulted in premature cancellous bone loss. Failure to account for species differences in thermoregulation may seriously confound interpretation of studies utilizing mice as preclinical models for osteoporosis.

Differential temporal effects of sclerostin antibody and parathyroid hormone on cancellous and cortical bone and quantitative differences in effects on the osteoblast lineage in young intact rats

Sclerostin antibody (Scl-Ab) and parathyroid hormone (PTH) are bone-forming agents that have different modes of action on bone, although a study directly comparing their effects has not been conducted. The present study investigated the comparative quantitative effects of these two bone-forming agents over time on bone at the organ, tissue, and cellular level; specifically, at the level of the osteoblast (Ob) lineage in adolescent male and female rats. Briefly, eight-week old male and female Sprague–Dawley rats were administered either vehicle, Scl-Ab (3 or 50mg/kg/week subcutaneously), or human PTH (1–34) (75μg/kg/day subcutaneously) for 4 or 26weeks. The 50mg/kg Scl-Ab and the PTH dose were those used in the respective rat lifetime pharmacology studies. Using robust stereological methods, we compared the effects of these agents specifically at the level of the Ob lineage in vertebrae from female rats. Using RUNX2 or nestin immunostaining, location, and morphology, the total number of osteoprogenitor subpopulations, Ob, and lining cells were estimated using the fractionator or proportionator estimators. Density estimates were also calculated referent to total bone surface, total Ob surface, or total marrow volume.Scl-Ab generally effected greater increases in cancellous and cortical bone mass than PTH, correlating with higher bone formation rates (BFR) at 4weeks in the spine and mid-femur without corresponding increases in bone resorption indices. The increases in vertebral BFR/BS at 4weeks attenuated with continued treatment to a greater extent with Scl-Ab than with PTH. At 4weeks, both Scl-Ab and PTH effected equivalent increases in total Ob number (Ob.N). Ob density on the formative surfaces (Ob.N/Ob.S) remained similar across groups while mineral apposition rate (MAR) was significantly higher with Scl-Ab at week 4, reflecting an increase in individual Ob vigor relative to vehicle and PTH. After 26weeks, Scl-Ab maintained BFR/BS with fewer Ob and lower Ob.N/Ob.S by increasing the Ob footprint (bone surface area occupied by an Ob) and increasing MAR, compared with PTH. The lower Ob.N and Ob.N/Ob.S with Scl-Ab at 26weeks were associated with decreased osteoprogenitor numbers compared with both vehicle and PTH, an effect not evident at week 4. Osteoprogenitor numbers were generally positively correlated with Ob.N across groups and timepoints, suggesting dynamic coordination between the progenitor and Ob populations. The time-dependent reductions in subpopulations of the Ob lineage with Scl-Ab may be integral to the greater attenuation or self-regulation of bone formation observed at the vertebra, as PTH required more Ob at the formative site with correlative increased numbers of progenitors compared with Scl-Ab indicating potentially greater stimulus for progenitor pool proliferation or differentiation.

Osteoblast-Specific γ-Glutamyl Carboxylase-Deficient Mice Display Enhanced Bone Formation With Aberrant Mineralization.

Vitamin K is a fat-soluble vitamin that is necessary for blood coagulation. In addition, it has bone-protective effects. Vitamin K functions as a cofactor of γ-glutamyl carboxylase (GGCX), which activates its substrates by carboxylation. These substrates are found throughout the body and examples include hepatic blood coagulation factors. Furthermore, vitamin K functions as a ligand of the nuclear receptor known as steroid and xenobiotic receptor (SXR) and its murine ortholog, pregnane X receptor (PXR). We have previously reported on the bone-protective role of SXR/PXR signaling by demonstrating that systemic Pxr-knockout mice displayed osteopenia. Because systemic Ggcx-knockout mice die shortly after birth from severe hemorrhage, the GGCX-mediated effect of vitamin K on bone metabolism has been difficult to evaluate. In this work, we utilized Ggcx-floxed mice to generate osteoblast-specific GGCX-deficient (Ggcx(Δobl/Δobl)) mice by crossing them with Col1-Cre mice. The bone mineral density (BMD) of Ggcx(Δobl/Δobl) mice was significantly higher than that of control Col1-Cre (Ggcx(+/+)) mice. Histomorphometrical analysis of trabecular bones in the proximal tibia showed increased osteoid volume and a higher rate of bone formation in Ggcx(Δobl/Δobl) mice. Histomorphometrical analysis of cortical bones revealed a thicker cortical width and a higher rate of bone formation in Ggcx(Δobl/Δobl) mice. Electron microscopic examination revealed disassembly of mineralized nodules and aberrant calcification of collagen fibers in Ggcx(Δobl/Δobl) mice. The mechanical properties of bones from Ggcx(Δobl/Δobl) mice tended to be stronger than those from control Ggcx(+/+) mice. These results suggest that GGCX in osteoblasts functions to prevent abnormal mineralization in bone formation, although this function may not be a prerequisite for the bone-protective effect of vitamin K.

Gender- and region-specific alterations in bone metabolism in Scarb1-null female mice.

A positive correlation between plasma levels of HDL and bone mass has been reported by epidemiological studies. As scavenger receptor class B, type I (SR-BI), the gene product of Scarb1, is known to regulate HDL metabolism, we recently characterized bone metabolism in Scarb1-null mice. These mice display high femoral bone mass associated with enhanced bone formation. As gender differences have been reported in HDL metabolism and SR-BI function, we investigated gender-specific bone alterations in Scarb1-null mice by microtomography and histology. We found 16% greater relative bone volume and 39% higher bone formation rate in the vertebrae from 2-month-old Scarb1-null females. No such alteration was seen in males, indicating gender- and region-specific differences in skeletal phenotype. Total and HDL-associated cholesterol levels, as well as ACTH plasma levels, were increased in both Scarb1-null genders, the latter being concurrent to impaired corticosterone response to fasting. Plasma levels of estradiol did not differ between null and WT females, suggesting that the estrogen metabolism alteration is not relevant to the higher vertebral bone mass in female Scarb1-null mice. Constitutively, high plasma levels of leptin along with 2.5-fold increase in its expression in white adipose tissue were measured in female Scarb1-null mice only. In vitro exposure of bone marrow stromal cells to ACTH and leptin promoted osteoblast differentiation as evidenced by increased gene expression of osterix and collagen type I alpha. Our results suggest that hyperleptinemia may account for the gender-specific high bone mass seen in the vertebrae of female Scarb1-null mice.

Impact of Maternal Prenatal Stress on Growth of the Offspring

Unperturbed fetal development is essential for future health of an individual. Previous studies have linked diseases of aging to harmful alterations that happen during fetal development. Given the significant long-term impact that intrauterine environment has on an individual's life, it was hypothesized that maternal stress during pregnancy will have negative effects on the offspring's prenatal and postnatal growth. To test this, twenty-eight female and seven male Wistar rats (Rattus norvegicus) were purchased and bred to produce 176 offspring. During pregnancy, dams were randomly divided into four groups (n=7, per group) and immobilization stress induced as follows; Group 1 (GW1): immobilization stress on days 1-7 of pregnancy, Group 2 (GW2): on days 8-14, Group 3 (GW3): on days 15-21, Group 4 (Controls): left undisturbed. Maternal cortisol hormone, food intake, and weight gain were monitored during pregnancy. Pups were raised under normal laboratory conditions and sacrificed at ages: 4, 8, 12, and 16 weeks to determine the effect of prenatal stress. At necropsy, the tibia was removed and processed for histology. Differences among groups were determined by T-test or analysis of variance (ANOVA). Linear regression analysis was performed to establish the relationship between stress in utero and indicators of bone development in offspring. P values ≤ 0.05 were considered significant. Cortisol hormone levels in controls were lower than those of stressed animals. Stressed dams consumed 12.5% less food per day compared to controls. Animals in GW1 and GW2 gained less weight during pregnancy but had larger litters than did GW3 or the control group. Offspring born to GW3 were heavier compared to all other groups. GW3 offspring had a higher rate of bone formation. In conclusion, stress during pregnancy resulted in increased cortisol and reduced food intake in mothers, but faster growth and higher weight gain in offspring compared to controls.

Histomorphometric Analysis of Bone Formation in Bony Defects Around Implants in Adult Dogs

The purpose of this study was to compare the bone formation of autogenous tooth ash treated with different temperatures. Heat treatment was rendered by powder after extraction of teeth from dogs. The bony defects were made at iliac and resorbable blast medium surfaced implant placement and bone graft was performed; no bone graft group (control group), low heat-treated tooth ash group (group 1), high heat-treated tooth ash group (group 2). Right side had healing periods of 12 weeks, and the left side had 6 weeks. Histomorphometrical analysis was performed at 12 weeks. The control group had poor bone formation and showed large loose connective tissue. Group 1 displayed good healing and bone formation. Group 2 showed higher rate of bone formation than group 1 and the control group. The high heat-treated tooth ash group showed a statistically significant increase in the rate of bone formation in the early stage. The heat-treated autogenous tooth ash powder showed excellent new bone formation. The temperature of heat treatment is an important factor in new bone formation. The high heat treatment was the optimal treatment method for making tooth ash than the low heat treatment.

Markers of Bone Resorption and Formation During Abstinence in Male Alcoholic Patients

Reduced bone mineral density (BMD) is commonly found in alcohol-dependent patients. Many risk factors have been reported, yet the course of markers of bone formation and resorption in abstinent alcoholic patients have not received much attention. In a prospective longitudinal study, we investigated BMD in male abstinent inpatients of an alcohol rehabilitation clinic aged 21 to 50years at baseline and after 8weeks of treatment. At baseline and at week 8, all patients had blood drawn for the analysis of liver function tests, calcium, phosphate, parathormone, 25-hydroxyvitamin D, osteocalcin (OC), serum crosslaps, sex hormones, and prolactin. BMD was determined by dual X-ray absorptiometry in the lumbar spine and the proximal right femur. We also determined the amount of physical activity prior to inpatient treatment by using the International Physical Activity Questionnaire (IPAQ). Low BMD was found in 15.1% of the patients for the lumbar spine, in 5.7% for the femoral neck, and in 1.9% for the total hip. BMD differed significantly from normal values, in the lumbar spine and in the femoral neck. At baseline, crosslaps were elevated in 34% of the patients, while OC levels were lowered in 17%. Over the course of the 8weeks, we found a significant increase in OC plasma levels, indicating a higher rate of bone formation during continuous abstinence. There were also positive correlations between IPAQ scores and BMD as reflected by Z-scores in all regions, pointing to a protective effect of physical activity. In summary, this report confirms earlier cross-sectional studies of lowered BMD in alcoholic noncirrhotic men. We could also demonstrate that the initial imbalance between bone formation and resorption seems to adjust toward a balance between the two during abstinence.

In vitro and in vivo effects of puerarin on promotion of osteoblast bone formation

To assess the effect of puerarin, a natural flavonoid found in Chinese Pueraria Lobata (Wild.) Ohwi, on promotion of new bone formation. Osteoblasts isolated from calvarial of newborn rats were cultured in vitro in the presence of puerarin at various concentrations. The viability of osteoblasts and alkaline phosphotase activity and mineral node formation were determined. In addition, osteoblasts seeded in the β-tricaclium phosphate scalfolds as bone substitute were implanted in rat dorsal muscles. Half -of the recipient rats received intramuscular injection of puerarin at 10 mg/(kg·d) for 7 days. Osteogenesis was analyzed by examining the histology after 4 weeks of implantation. The viability of osteoblasts treated with puerarin at either 40 or 80 μmol/L was significantly higher than that of the control (P<0.05 and P<0.01, respectively). Alkaline phosphatase and mineral modules were significantly increased in osteoblasts cultured with puerarin at 40 or 80 mol/L when compared with that of the untreated cells. The puerarin-treated rats had a higher rate of bone formation in the osteoblast implants than the control rats (6.35% vs. 1.32%, respectively, P<0.05). Puerarin was able to affect osteoblast proliferation and differentiation, and promote the new bone formation in osteoblast implants.

Periradicular Tissue Responses to Biologically Active Molecules or MTA When Applied in Furcal Perforation of Dogs' Teeth

The aim of this study was the comparative evaluation of inflammatory reactions and tissue responses to four growth factors, or mineral trioxide aggregate (MTA), or a zinc-oxide-eugenol-based cement (IRM) as controls, when used for the repair of furcal perforations in dogs' teeth. Results showed significantly higher inflammatory cell response in the transforming growth factorβ1 (TGFβ1) and zinc-oxide-eugenol-based cement (IRM) groups and higher rates of epithelial proliferation in the TGFβ1, basic fibroblast growth factor (bFGF), and insulin growth factor-I (IGF-I) groups compared to the MTA. Significantly higher rates of bone formation were found in the control groups compared to the osteogenic protein-1 (OP-1). Significantly higher rates of cementum formation were observed in the IGF-I and bFGF groups compared to the IRM. None of the biologically active molecules can be suggested for repairing furcal perforations, despite the fact that growth factors exerted a clear stimulatory effect on cementum formation and inhibited collagen capsule formation. MTA exhibited better results than the growth factors.

Effects of early exercise on metacarpophalangeal joints in horses

To determine the effects of exercise at an early age on tissues in the metacarpophalangeal joints of horses. Twelve 18-month-old horses. All horses were pasture reared, but 6 horses had additional exercise starting at 3 weeks of age until 18 months of age. At that time, computed tomography, articular cartilage metabolism evaluation, and histologic assessments of synovial membrane, articular cartilage, and subchondral bone were performed. Exercised horses had fewer gross lesions, less articular cartilage matrix staining in the dorsal aspect of the condyle, greater bone fraction in the dorsolateral aspect of the condyle, and higher bone formation rate, compared with nonexercised horses. Exercise at a young age may be protective to joints, although more research is needed to characterize changes in articular cartilage matrix. Results suggested that exercise can be safely imposed at an early age.