Relationships between obesity markers and bone parameters in community-dwelling older adults

BACKGROUND

Osteoporosis is an age-related condition that can lead to fragility fractures and other serious consequences. The literature data on the impact of obesity on bone health are contradictory. The main reasons for this discrepancy could be the imperfect nature of the body mass index (BMI) as a marker of obesity, the metabolic status (inflammation and metabolically healthy obesity), and/or heterogeneity in bone variables and architecture or sex.

AIMS

To examine the relationship between bone variables and three validated obesity criteria.

METHODS

In this cross-sectional study, participants were classified as obese according to their BMI, waist circumference (WC), and fat mass (FM). Bone variables and architecture were assessed using dual-energy X-ray absorptiometry and peripheral quantitative computed tomography, respectively.

RESULTS

One hundred sixty-eight adults aged 55 or over (men: 68%) were included. 48 (28%) participants were obese according to the BMI, with 108 (64%) according to the FM, and 146 (87%) according to the WC. Bone variables were positively correlated with WC and BMI (Pearson's r = 0.2-0.42). In men only, the obesity measures were negatively correlated with cortical bone density (Pearson's r = - 0.32 to - 0.19) and positively correlated with cortical bone area (Pearson's r = 0.22-0.39).

CONCLUSION

Our findings indicate that independent of sex and obesity criteria, when significant, being obese seems to lead to higher bone parameters than being non-obese, except for cortical bone density. Thus, in the obese population, assessing cortical density might help the physician to identify bone alteration. Further researches are needed to confirm our findings.

Effect of achieving bone sterilisation on bone architecture and bone marrow, in an experimental rabbit model of osteomyelitis caused by carbapenemase-producing Enterobacterales

OBJECTIVES

Natural history and treatment of bone infections caused by carbapenemase-producing Enterobacterales (CPE) are poorly defined. We evaluated the effect of treatment on the progression of subacute osteomyelitis in a rabbit model.

METHODS

Two isolates were used: a KPC-producing Klebsiella pneumoniae and an Escherichia coli harbouring blaOXA-48 and blaCTX-M15 inserts, both susceptible to gentamicin, colistin, fosfomycin, and ceftazidime-avibactam. Osteomyelitis was induced in rabbits by tibial injection of 2 × 108 colony-forming units/mL. Antibiotics were started 14 d later, for 7 d, in 6 groups of 12 rabbits. Three days after treatment completion (D24), rabbits were euthanised and bones were cultured. Bone marrow and bone architecture macroscopic changes were evaluated through analysis of pictures by investigators unaware of the rabbit treatment group and microbiological outcome, using scales ranging from 0 (normal) to 3 (severe lesions) depending on modifications.

RESULTS

Bone marrow modifications induced by local infection were similar between prematurely deceased animals and non-sterilised animals (P = 0.14) but differed significantly from animals that achieved bone sterilisation after treatment (P = 0.04). Conversely, when comparing bone deformity, rabbits who died early (n = 13) had similar bone architecture as those achieving bone sterilisation (P = 0.12), as opposed to those not sterilised after treatment (P = 0.04). After a multivariate logistic regression, bone marrow scale ≤2 was associated with bone sterilisation (P < 0.001), and bone architecture scale ≤2 was associated with bone sterilisation (adjusted odds ratio = 2.7; 95% confidence interval 1.14-6.37) and KPC infection (adjusted odds ratio = 5.1; 95% confidence interval 2.17-12.13).

CONCLUSION

Effective antibacterial treatment reduces bone architecture distortion and bone marrow changes. These variables may be used as proxy for bone sterilisation.

Relationship between protein intake and bone architecture or bone mineral density among dynapenic-obese older adults

OBJECTIVE

The current study aimed to assess the relationship between protein intake and bone parameters among dynapenic-obese older adults.

DESIGN

The current study is a secondary analysis with an a posteriori and exploratory design.

SETTING

Subjects were recruited from the community via social communication (flyers and meetings in community centres) in the Great Montreal area.

PARTICIPANTS

Twenty-six subjects were divided a posteriori into two groups according to their usual protein intake: PROT-: < 1 g/kg per d (n 13; women: 53·8 %; 66·5 (sd 3·3) years) and PROT+: > 1·2 g/kg per d (n 13; women: 61·5 %; 67·2 (sd 2·7) years).

RESULTS

Both groups were comparable for age (PROT-: 66·5 (sd 3·3) v. PROT+: 67·2 (sd 2·7) years, P = 0·61) and gender (women: PROT-: n 7; 53·8 % v. PROT+: n 8; 61·5 %, P = 0·69). The PROT- group had a higher marrow area (P = 0·049), a greater bone compressive strength (P = 0·048) and a larger total bone area (P = 0·045) than the PROT+ group. However, no significant difference between the two groups was observed regarding body composition (fat and lean masses) or muscle composition.

CONCLUSIONS

A lower protein intake seems to be associated with bone sizes, which influence bone strength, but do not influence bone density among dynapenic-obese older people.

Bisphosphonate-related osteonecrosis induced change in alveolar bone architecture in rats with participation of Wnt signaling

OBJECTIVE

This work aimed to study the role of inflammation in medication-related osteonecrosis of the jaw (MRONJ) in rats with focus on Wnt signaling.

METHODS

A total of 36 female Wistar rats (12 weeks ± 200 g) were divided into 2 groups (n = 6) in 3 experiments: saline (SAL) and zoledronic acid (ZOL). For MRONJ induction, rats received 0.1 mg/kg of ZOL (ip) 3×/week for 9 weeks. Animals from the SAL group received 0.1 mg/kg of 0.9% SAL, ip 3×/week for 9 weeks. On the 8th week, 3 left upper molars were extracted, and on the 11th week, they were euthanized. Maxillae were evaluated by macroscopic and histopathological analyses; scanning electron microscopy (SEM); immunohistochemistry for DKK-1, Wnt 10b, and caspase-3; and Raman spectrometry. Gingiva was also collected for TNF-α e IL-1β quantification.

RESULTS

Bone necrosis was confirmed by healing impairment, reduced number of viable osteocytes, increased caspase-3 immunoexpression, and increased number of empty lacunae (p < 0.05). ZOL enhanced inflammation and increased gingival levels of IL-1β and TNF-α (p < 0.05). Irregular indentations were seen on bone after ZOL administration. Bone necrosis was marked by reduced amount of total and type I collagen. ZOL reduced the mineral/matrix ratio and increased carbonate/phosphate ratio. It was observed a significant reduction on Wnt10b and beta-catenin immunolabeling in the bone tissue of ZOL group.

CONCLUSION

In summary, MRONJ model caused bone necrosis due to intense inflammation. Wnt signaling seems to play an important role in this process.

CLINICAL RELEVANCE

New therapeutic strategies focusing on Wnt pathway can provide an interesting approach for future treatments.

A Comparison of Peripheral Imaging Technologies for Bone and Muscle Quantification: A Review of Segmentation Techniques

Musculoskeletal science has developed many overlapping branches, necessitating specialists from 1 area of focus to often require the expertise in others. In terms of imaging, this means obtaining a comprehensive illustration of bone, muscle, and fat tissues. There is currently a lack of a reliable resource for end users to learn about these tissues' imaging and quantification techniques together. An improved understanding of these tissues has been an important progression toward better prediction of disease outcomes and better elucidation of their interaction with frailty, aging, and metabolic disorders. Over the last decade, there have been major advances into the image acquisition and segmentation of bone, muscle, and fat features using computed tomography (CT), magnetic resonance imaging (MRI), and peripheral modules of these systems. Dedicated peripheral quantitative musculoskeletal imaging systems have paved the way for mobile research units, lower cost clinical research facilities, and improved resolution per unit cost paid. The purpose of this review was to detail the segmentation techniques available for each of these peripheral CT and MRI modalities and to describe advances in segmentation methods as applied to study longitudinal changes and treatment-related dynamics. Although the peripheral CT units described herein have established feasible standardized protocols that users have adopted globally, there remain challenges in standardizing MRI protocols for bone and muscle imaging.

A multi-factorial analysis of bone morphology and fracture strength of rat femur in response to ovariectomy

BACKGROUND

Postmenopausal osteoporosis develops due to a deficiency of estrogen that causes a decrease in bone mass and changes in the macro- and micro-architectural structure of the bone, leading to the loss of mechanical strength and an increased risk of fracture. Although the assessment of bone mineral density (BMD) has been widely used as a gold standard for diagnostic screening of bone fracture risks, it accounts for only a part of the variation in bone fragility; thus, it is necessary to consider other determinants of bone strength. Therefore, we aimed to comprehensively evaluate the architectural changes of the bone that influence bone fracture strength, together with the different sensitivities of cortical and trabecular bone in response to ovariectomy (OVX).

METHODS

Bone morphology parameters were separately analyzed both in cortical and in trabecular bones, at distal-metaphysis, and mid-diaphysis of OVX rat femurs. Three-point bending test was performed at mid-diaphysis of the femurs. Correlation of OVX-induced changes of morphological parameters with breaking force was analyzed using Pearson's correlation coefficient.

RESULTS

OVX resulted in a decline in the bone volume of distal-metaphysis trabecular bone, but an increase in distal-metaphysis and mid-diaphysis cortical bone volume. Tissue mineral density (TMD) remained unchanged in both the trabecular and cortical bone of the distal metaphysis but decreased in cortical bone of the mid-diaphysis. The OVX significantly increased the breaking force at mid-diaphysis of the femurs.

CONCLUSIONS

OVX decreased the trabecular bone volume of the distal-metaphysis and increased the cortical bone volume of the distal-metaphysis and mid-diaphysis. Despite the reduction in TMD and increased cortical porosity, bone fracture strength increased in the mid-diaphysis after OVX. These results indicate that analyzing a single factor, i.e., BMD, is not sufficient to predict the absolute fracture risk of the bone, as OVX-induced bone response vary, depending on the bone type and location. Our results strongly support the necessity of analyzing bone micro-architecture and site specificity to clarify the true etiology of osteoporosis in a clinical setting.

Mutant cartilage oligomeric matrix protein (COMP) compromises bone integrity, joint function and the balance between adipogenesis and osteogenesis

Mutations in COMP (cartilage oligomeric matrix protein) cause severe long bone shortening in mice and humans. Previously, we showed that massive accumulation of misfolded COMP in the ER of growth plate chondrocytes in our MT-COMP mouse model of pseudoachondroplasia (PSACH) causes premature chondrocyte death and loss of linear growth. Premature chondrocyte death results from activation of oxidative stress and inflammation through the CHOP-ER pathway and is reduced by removing CHOP or by anti-inflammatory or antioxidant therapies. Although the mutant COMP chondrocyte pathologic mechanism is now recognized, the effect of mutant COMP on bone quality and joint health (laxity) is largely unknown. Applying multiple analytic approaches, we describe a novel mechanism by which the deleterious consequences of mutant COMP retention results in upregulation of miR-223 disturbing the adipogenesis - osteogenesis balance. This results in reduction in bone mineral density, bone quality, mechanical strength and subchondral bone thickness. These, in addition to abnormal patterns of ossification at the ends of the femoral bones likely contribute to precocious osteoarthritis (OA) of the hips and knees in the MT-COMP mouse and PSACH. Moreover, joint laxity is compromised by abnormally thin ligaments. Altogether, these novel findings align with the PSACH phenotype of delayed ossification and bone age, extreme joint laxity and joint erosion, and extend our understanding of the underlying processes that affect bone in PSACH. These results introduce a novel finding that miR-223 is involved in the ossification defect in MT-COMP mice making it a therapeutic target.

Effect of Sequential Treatment with Bisphosphonates After Teriparatide in Ovariectomized Rats: A Direct Comparison Between Risedronate and Alendronate

Teriparatide (TPTD), a recombinant human parathyroid hormone N-terminal fragment (1-34), is a widely used bone anabolic drug for osteoporosis. Sequential treatment with antiresorptives such as bisphosphonates after TPTD discontinuation is generally recommended. However, relative effects of bisphosphonates have not been determined. In the present study, we directly compared effects of risedronate (RIS) and alendronate (ALN) on bone mineral density (BMD), bone turnover, structural property and strength in ovariectomized (OVX) rats, when administered after TPTD. Female Sprague Dawley rats were divided into one sham-operated and eight ovariectomized groups. TPTD, RIS, and ALN were given subcutaneously twice per week for 4 or 8 weeks after 4 week treatment with TPTD. TPTD significantly increased BMD (+9.6%) in OVX rats after 4 weeks of treatment. 8 weeks after TPTD withdrawal, vehicle-treated group showed a blunted BMD increase of +8.4% from the baseline. In contrast, 8 weeks of treatment with RIS and ALN significantly increased BMD to 17.4 and 21.8%, respectively. While ALN caused a consistently larger increase in BMD, sequential treatment with RIS resulted in lower Tb.Sp compared to ALN in the fourth lumbar vertebra as well as in greater stiffness in compression test. In conclusion, the present study demonstrated that sequential therapy with ALN and RIS after TPTD both improved bone mass and structure. Our results further suggest that RIS may have a greater effect on improving bone quality and stiffness than ALN despite less prominent effect on BMD. Further studies are necessary to determine clinical relevance of these findings to fracture rate.

Effects of fructose-induced metabolic syndrome on rat skeletal cells and tissue, and their responses to metformin treatment

AIMS

Deleterious effects of metabolic syndrome (MS) on bone are still controversial. In this study we evaluated the effects of a fructose-induced MS, and/or an oral treatment with metformin on the osteogenic potential of bone marrow mesenchymal stromal cells (MSC), as well as on bone formation and architecture.

METHODS

32 male 8week-old Wistar rats were assigned to four groups: control (C), control plus oral metformin (CM), rats receiving 10% fructose in drinking water (FRD), and FRD plus metformin (FRDM). Samples were collected to measure blood parameters, and to perform pQCT analysis and static and dynamic histomorphometry. MSC were isolated to determine their osteogenic potential.

RESULTS

Metformin improved blood parameters in FRDM rats. pQCT and static and dynamic histomorphometry showed no significant differences in trabecular and cortical bone parameters among groups. FRD reduced TRAP expression and osteocyte density in trabecular bone and metformin only normalized osteocyte density. FRD decreased the osteogenic potential of MSC and metformin administration could revert some of these parameters.

CONCLUSIONS

FRD-induced MS shows reduction in MSC osteogenic potential, in osteocyte density and in TRAP activity. Oral metformin treatment was able to prevent trabecular osteocyte loss and the reduction in extracellular mineralization induced by FRD-induced MS.

Combined treatment with a transforming growth factor beta inhibitor (1D11) and bortezomib improves bone architecture in a mouse model of myeloma-induced bone disease

Multiple myeloma (MM) patients frequently develop tumor-induced bone destruction, yet no therapy completely eliminates the tumor or fully reverses bone loss. Transforming growth factor-β (TGF-β) activity often contributes to tumor-induced bone disease, and pre-clinical studies have indicated that TGF-β inhibition improves bone volume and reduces tumor growth in bone metastatic breast cancer. We hypothesized that inhibition of TGF-β signaling also reduces tumor growth, increases bone volume, and improves vertebral body strength in MM-bearing mice. We treated myeloma tumor-bearing (immunocompetent KaLwRij and immunocompromised Rag2-/-) mice with a TGF-β inhibitory (1D11) or control (13C4) antibody, with or without the anti-myeloma drug bortezomib, for 4weeks after inoculation of murine 5TGM1 MM cells. TGF-β inhibition increased trabecular bone volume, improved trabecular architecture, increased tissue mineral density of the trabeculae as assessed by ex vivo micro-computed tomography, and was associated with significantly greater vertebral body strength in biomechanical compression tests. Serum monoclonal paraprotein titers and spleen weights showed that 1D11 monotherapy did not reduce overall MM tumor burden. Combination therapy with 1D11 and bortezomib increased vertebral body strength, reduced tumor burden, and reduced cortical lesions in the femoral metaphysis, although it did not significantly improve cortical bone strength in three-point bending tests of the mid-shaft femur. Overall, our data provides rationale for evaluating inhibition of TGF-β signaling in combination with existing anti-myeloma agents as a potential therapeutic strategy to improve outcomes in patients with myeloma bone disease.

Structural differences in cortical shell properties between upper and lower human fibula as described by pQCT serial scans. A biomechanical interpretation

This study describes the structural features of fibula cortical shell as allowed by serial pQCT scans in 10/10 healthy men and women aged 20-40years. Indicators of cortical mass (mineral content -BMC-, cross-sectional area -CSA-), mineralization (volumetric BMD, vBMD), design (perimeters, thickness, moments of inertia -MIs-) and strength (Bone Strength Indices, BSIs; polar Strength-Strain Index, pSSI) were determined. All cross-sectional shapes and geometrical or strength indicators suggested a sequence of five different regions along the bone, which would be successively adapted to 1. transmit loads from the articular surface to the cortical shell (near the proximal tibia-fibular joint), 2. favor lateral bending (central part of upper half), 3. resist lateral bending (mid-diaphysis), 4. favor lateral bending again (central part of the lower half), and 5. resist bending/torsion (distal end). Cortical BMC and the cortical/total CSA ratio were higher at the midshaft than at both bone ends (p<0.001). However, all MIs, BSIs and pSSI values and the endocortical perimeter/cortical CSA ratio (indicator of the mechanostat's ability to re-distribute the available cortical mass) showed a "W-shaped" distribution along the bone, with maximums at the mid-shaft and at both bone's ends (site effect, p<0.001). The correlation coefficient (r) of the relationship between MIs (y) and cortical vBMD (x) at each bone site ("distribution/quality" curve that describes the efficiency of distribution of the cortical tissue as a function of the local tissue stiffness) was higher at proximal than distal bone regions (p<0.001). The results from the study suggest that human fibula is primarily adapted to resist bending and torsion rather than compression stresses, and that fibula's bending strength is lower at the center of its proximal and distal halves and higher at the mid-shaft and at both bone's ends. This would favor, proximally, the elastic absorption of energy by the attached muscles that rotate or evert the foot, and distally, the widening of the heel joint and the resistance to excessive lateral bending. Results also suggest that biomechanical control of structural stiffness differs between proximal and distal fibula.

Vertebral body morphology is associated with incident lumbar vertebral fracture in postmenopausal women. The OFELY study

We investigate the predictive role of vertebral anterior cortical curvature and height heterogeneity in the occurrence of vertebral fractures in postmenopausal women. Women who will fracture had shorter vertebral height, greater heterogeneity of height than those who will not fracture, and their anterior vertebral body edge was less concave.

INTRODUCTION

Vertebral morphology has been demonstrated to be associated with further risk of fracture. The aim of this study was to analyze vertebral anterior cortical curvature (Ct.curv) and vertebral height heterogeneity in postmenopausal women before the occurrence of a vertebral fracture.

METHODS

This case-control study included 29 postmenopausal women who have underwent incident lumbar vertebral fractures (mean age 71 ± 9 years, mean time to fractures 9 ± 4 years), age-matched with 57 controls. From lateral X-rays of lumbar spine radiographs (T12 to L4), the following parameters were measured: (1) the posterior, middle, and anterior vertebral heights; (2) the heterogeneity of heights evaluated by the coefficient of variation of these three variables; (3) antero-posterior width, a 2D estimator of cross-sectional area; and (4) Ct.curv.

RESULTS

Mean vertebral heights were significantly lower among women who fractured than in controls (p < 0.05). The anterior and middle heights were significantly lower at L4 and L3 levels in fracture group (p = 0.02). The heterogeneity of vertebral height was significantly greater in the fracture group (p = 0.003). In addition, fractured patients had a significantly higher Ct.curv on L3 (p = 0.04). After adjustment for bone mineral density (BMD), only the heterogeneity of vertebral height remained significant (p = 0.005).

CONCLUSION

The current case-control study confirmed the association between vertebral height and occurrence of future vertebral fracture in postmenopausal women. The vertebrae with the smallest Ct.curv tended to fracture less often, and the heterogeneity of vertebral heights was associated with future fracture independently of BMD. An additional validation in a prospective study would be needed to confirm these initial results.

High-fat diet-induced obesity triggers alveolar bone loss and spontaneous periodontal disease in growing mice

Background

The relationship between high-fat food consumption and obesity is well-established. However, it is as yet unclear whether high-fat diet (HFD)-induced obesity in childhood and adolescence determines age-related changes in jaw bone health. The aim of this study is to examine the age-related influence of HFD-induced obesity on mandibular bone architecture and the structure of the periodontium in growing mice.

Methods

Male C57BL/6 J mice (6-weeks-old) were divided into two groups (n = 6 each): the control group received a control diet and the experimental group a HFD. After treatment for 4, 8, or 12 weeks, trabecular and cortical bone architecture was assessed using micro-computed tomography. The periodontium and alveolar bone structure were evaluated by histopathology.

Results

In HFD mice, body weight, serum total cholesterol, and serum leptin levels were significantly higher than those in age-matched control mice (p < 0.05, all comparisons). Reductions in trabecular bone volume and in cortical bone growth (measured as the thickness and cross sectional area) in HFD mice were significant compared with the control mice after 4 weeks of treatment (p < 0.05, both comparisons). Significant decreases in cortical bone density in HFD-fed vs. age-matched control mice were determined after 12 weeks (p < 0.05). In the HFD mice, the periodontal ligament fibres were disrupted, having lost their orientation with respect to the bone surface, and constriction of the periodontal ligament space was inhibited.

Conclusions

These results suggest that HFD-induced obesity during growth not only triggers mandibular osteoporosis but also increases the risk of spontaneous periodontal disease.

Chronic administration of Glucagon-like peptide-1 receptor agonists improves trabecular bone mass and architecture in ovariectomised mice

Some anti-diabetic therapies can have adverse effects on bone health and increase fracture risk. In this study, we tested the skeletal effects of chronic administration of two Glucagon-like peptide-1 receptor agonists (GLP-1RA), increasingly used for type 2 diabetes treatment, in a model of osteoporosis associated bone loss and examined the expression and activation of GLP-1R in bone cells. Mice were ovariectomised (OVX) to induce bone loss and four weeks later they were treated with Liraglutide (LIR) 0.3mg/kg/day, Exenatide (Ex-4) 10 μg/kg/day or saline for four weeks. Mice were injected with calcein and alizarin red prior to euthanasia, to label bone-mineralising surfaces. Tibial micro-architecture was determined by micro-CT and bone formation and resorption parameters measured by histomorphometric analysis. Serum was collected to measure calcitonin and sclerostin levels, inhibitors of bone resorption and formation, respectively. GLP-1R mRNA and protein expression were evaluated in the bone, bone marrow and bone cells using RT-PCR and immunohistochemistry. Primary osteoclasts and osteoblasts were cultured to evaluate the effect of GLP-1RA on bone resorption and formation in vitro. GLP-1RA significantly increased trabecular bone mass, connectivity and structure parameters but had no effect on cortical bone. There was no effect of GLP-1RA on bone formation in vivo but an increase in osteoclast number and osteoclast surfaces was observed with Ex-4. GLP-1R was expressed in bone marrow cells, primary osteoclasts and osteoblasts and in late osteocytic cell line. Both Ex-4 and LIR stimulated osteoclastic differentiation in vitro but slightly reduced the area resorbed per osteoclast. They had no effect on bone nodule formation in vitro. Serum calcitonin levels were increased and sclerostin levels decreased by Ex-4 but not by LIR. Thus, GLP-1RA can have beneficial effects on bone and the expression of GLP-1R in bone cells may imply that these effects are exerted directly on the tissue.

Are radiographic indices reliable indicators for quantitative bone mineral density and vitamin D status after femoral neck fractures? A retrospective study in 112 elderly patients

BACKGROUND

Radiographic parameters and indices obtained from hip x-rays are a potential tool to promptly estimate bone quality in elderly hip fracture patients. Preoperative decision in whether to use cemented or cement augmented implants might be supported by this information and thus improve patient safety. Subsequently, this study was conducted to evaluate radiographic parameters as a prescreening tool for bone quality.

METHODS

A retrospective analysis of 112 elderly patients with a femoral neck fracture after low-energy trauma was performed (81 % female, 19 % male). Three radiological indices were calculated on hip x-rays: cortical index antero-posterior CTI (ap), cortical index lateral CTI (lat) and canal to calcar ratio CCR. These indices were analyzed for correlations with DXA T-Scores and serum 25-hydroxyvitamin D (25(OH)D) using the Spearman test.

RESULTS

Median age of patients was 80 (IQR 72-86) years. A linear correlation was found for CTI (lat) and T-Score at the total hip (p < 0.001, r = 0.589), femoral neck (p = 0.005, r = 0.405) and the lumbar spine (p = 0.002, r = 0.299). A significant correlation was also indicated between CTI (lat) and 25(OH)D (p = 0.002, r = 0.293). CTI (lat) at a cut-off level of 0.4 showed a sensitivity of 79 % and a specificity of 56 % in predicting a T-score ≤ -2.5 at the total hip. Gender specific analysis revealed a higher sensitivity (100 %) and specificity (73 %) of CTI (lat) at a cut-off level of 0.4 for men. For severe vitamin D deficiency (<10 ng/ml) sensitivity and specificity were 75 % and 65 %.

CONCLUSION

Radiographic indices as the CTI (lat) exhibit a direct correlation to BMD and serum 25OH vitamin D levels. A CTI (lat) cut-off level of 0.4 is recommended for identifying patients at risk of osteoporosis expressed by T-Scores ≤ -2.5 and severe vitamin D deficiency.

Bone properties of the humeral head and resistance to screw cutout

Surgical treatment of fractures involving the proximal humeral head is hampered by complications. Screw cutout is the major pitfall seen in connection with rigid plating. We have exploited a bony explanation for this phenomenon.

Protein quality affects bone status during moderate protein restriction in growing mice

Adequate protein intake during development is critical to ensure optimal bone gain and to attain a higher peak bone mass later on. We hypothesized that the quality of the dietary protein is of prime importance for bone physiology during moderate protein restriction. The target population was growing Balb/C mice. We compared two protein restricted diets (6% of total energy as protein), one based on soy (LP-SOY) and one based on casein (LP-CAS). For comparison, a normal protein soy-based control group (NP-SOY) and a low protein group receiving an anabolic daily parathyroid hormone (PTH) 1-34 injection (LP-SOY+PTH) were included in the protocol. After 8weeks, LP-SOY mice had reduced body weights related to a lower lean mass whereas LP-CAS mice were not different from the NP-SOY group. LP-SOY mice were characterized by lower femoral cortical thickness, bone volume, trabecular number and thickness and increased medullar adiposity when compared to both the LP-CAS and NP-SOY groups. However, the dietary intervention had no effect on the vertebral parameters. The negative effect of the LP-SOY diet was correlated to an impaired bone formation as shown by the reduced P1NP serum level as well as the reduced osteoid surfaces and bone formation rate in the femur. PTH injection in LP-SOY mice had no effect on total weight or lean mass, but improved all bone parameters at both femoral and vertebral sites, suggesting that amino acid deficiency was not the primary reason for degraded bone status in mice consuming soy protein. In conclusion, our study showed that under the same protein restriction (6% of energy), a soy diet leads to impaired bone health whereas a casein diet has little effect when compared to a normal protein control.

Waterjet drilling in porcine bone: the effect of the nozzle diameter and bone architecture on the hole dimensions

Using waterjets instead of rigid drill bits for bone drilling can be beneficial due to the absence of thermal damage and a consequent sharp cut. Additionally, waterjet technology allows the development of flexible instruments that facilitate maneuvering through complex joint spaces. Controlling the drilling depth is of utmost importance to ensure clinical safety, but is challenging given the local variations in structural properties of the bone. The goal of this study was to deduce a descriptive mathematical equation able to predict the hole depth and diameter based on the local structural properties of the bone at given waterjet diameters. 210 holes were drilled in porcine femora and tali with waterjet diameters (Dnozzle) of 0.3, 0.4, 0.5 and 0.6mm at a pressure of 700bar and a 5s jet time. Hole depths (Lhole), diameters (Dhole) and bone architectural properties were determined using microCT scans. The most important bone architectural property is the bone volume fraction (BV/TV), resulting in the significant predictive equations: Lhole=34.3 (⁎) Dnozzle(2)-17.6 (⁎) BV/TV+10.7 (R(2)=0.90, p<0.001), and hole Dhole=3.1(⁎) Dnozzle-0.45(⁎)BV/TV+0.54 (R(2)=0.58, p=0.02), with Lhole, Dhole and Dnozzle in mm. Drilling to a specific depth in bone tissue with a known BV/TV is possible, thereby contributing to the safe application of waterjet technology in orthopedic surgery.