POS1111 DIAGNOSIS OF OSTEOPOROSIS USING RADIOFREQUENCY ECHOGRAPHIC MULTI SPECTROMETRY (REMS) AT THE LUMBAR SPINE IN PATIENTS WITH DIFFERENT BODY MASS INDEX

Background:

In recent years, the technology based on the analysis of raw ultrasound signals, Radiofrequency Echographic Multi Spectrometry (REMS), has been validated against Dual-energy X-ray Absorptiometry (DXA) for the diagnosis of osteoporosis and risk fracture prediction.

Objectives:

The aim of this multicenter observational study was to evaluate the diagnostic performance of REMS with respect to DXA in patients with different body mass index (BMI) categories.

Methods:

The inclusion criteria were: Caucasian women; age between 30 and 90 years; referral by their clinician for spinal DXA assessment; absence of significant walking impairment; signed informed consent.

Patients underwent DXA and REMS scans at the lumbar spine, according to the procedures described in Di Paola et al. [1], including an a-posteriori quality check of the examinations in order to guarantee the maximum reliability of the diagnostic outputs.

Three groups of patients were considered according to BMI:: underweight (BMI<18.5 kg/m2), normal weight (BMI≥18.5 kg/m2 and <25 kg/m2), and overweight/obese (BMI≥25 kg/m2). DXA and REMS BMD values were also stratified in 3 diagnostic categories: osteoporotic, osteopenic, or healthy.

The degree of correlation between DXA and REMS BMD values was quantified by calculating Pearson’s correlation coefficient (r). The diagnostic concordance between REMS and DXA was assessed by Cohen’s K considering the 3 diagnostic categories. REMS´s sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for discriminating patients with and without osteoporosis were also calculated using DXA outcomes as reference. The same statistics were calculated accepting a 0.3 T-score tolerance on T-score values of borderline cases [1].

Results:

Overall, 4282 patients were enrolled and, after the quality check, 3501 couples of scans were included in the analyses. Of these patients, 122 (3.5%) were underweight, 1964 (56.1%) were normal weight, and 1415 (40.4%) were overweight. The results of the diagnostic performance in patients after BMI stratification are reported in Table 1.

Conclusion:

We observed an excellent correlation between REMS-based diagnosis with respect to the osteoporosis diagnosis performed by DXA in patients from each BMI category. These results indicate that lumbar spine REMS analysis is a suitable and accurate diagnostic tool for patients with different BMI.

References:

[1]Di Paola M et al. Osteoporos Int. 2019 Feb;30(2):391-402.

Table 1.

Diagnostic performance of REMS with respect to DXA considered as reference for patients of different body size.

BMIcategoriesrNo tolerance0.3 T-score toleranceSens.Spec.PPVNPVKSens.Spec.PPVNPVKUnderweight0.94697.591.586.898.40.8998.293.289.299.30.91Normal weight0.94692.694.487.096.90.8597.596.792.399.00.93Overweight0.93086.795.884.896.40.8296.397.892.199.00.93

Abbreviations: BMI = body mass index; r = Pearson correlation coefficient; Sens. = sensitivity; Spec. = specificity; PPV = positive predictive value; NPV = negative predictive value; K = Cohen’s K.

The authors BC, ED, ADP, ML, MM, XN, DOC are equal contributors listed in alphabetical order.

Disclosure of Interests:

None declared.

In-vitro comparison of hydroxyapatite coatings obtained by cold spray and conventional thermal spray technologies

Hydroxyapatite (HA) coatings onto Ti6Al4V alloy substrates were obtained by several thermal spray technologies: atmospheric plasma spray (APS) and high velocity oxy fuel (HVOF), together with the cold spray (CS) technique. A characterization study has been performed by means of surface and microstructure analyses, as well as biological performance. In-vitro tests were performed with primary human osteoblasts at 1, 7 and 14 days of cell culture on substrates. Cell viability was tested by MTS and LIVE/DEAD assays, cell differentiation by alkaline phosphatase (ALP) quantification, and cell morphology was analyzed by scanning electron microscopy. The HA coatings showed an increase of HA crystallinity from 62,4% to 89%, but also an increase of hydrophilicity from ∼32° to 0°, with the decrease of the operating temperature of the thermal spray techniques (APS > HVOF > CS). Additionally, APS HA coatings showed more surface micro-features than HVOF and CS HA coatings; cells onto APS HA coatings showed faster attachment by acquiring osteoblastic morphology in comparison with the rounded cell morphology observed onto CS HA coatings at 1 day of cell culture. HVOF HA coatings also showed proper cell adherence but did not show extended filopodia as cells onto APS HA coatings. However, at 14 days of cell culture, higher cell proliferation and differentiation was detected on HA coatings with higher crystallinity (HVOF and CS techniques). Cell attachment is suggested to be favoured by surface micro-features but also moderate surface wettability whereas cell proliferation and differentiation is suggested to be highly influenced by HA crystallinity and crystal size.

The impact of hip fracture on health-related quality of life and activities of daily living: the SPARE-HIP prospective cohort study

PURPOSE

The medical morbidity and mortality associated with neck of femur fractures is well-documented, whereas there is limited data for patient-reported outcomes. The aim of this study was to characterize the impact of neck of femur fractures on activities of daily living and patient-reported health-related quality of life.

METHODS

Design and participants: Multicentric prospective cohort study. Consecutive sample patients with fragility hip fracture over 50 years old admitted in 48 hospitals in Spain.

OUTCOMES

daily living activity function (Barthel Index) and health-related quality of life (EQ-5D) pre-fracture, admission to hospital and at 1- and 4-month follow-up post-fracture.

STATISTICS

Barthel and EQ-5D over time are described as mean (SD) and median (interquartile range).

RESULTS

A total of 997 patients were recruited at baseline with 4-month outcomes available for, and 856 patients (89.5%). Barthel Index fell from 78.77 (23.75) at baseline to 43.62 (19.86) on admission to hospital with the fracture. Scores partially recovered to 54.89 (25.40) and 64.09 (21.35) at 1- and 4-month post-fracture, respectively. EQ-5D fell from a median of 0.75 (0.47-0.91) to - 0.01 (- 0.03 to 0.51) on admission. Partial recovery was observed again to (0.51 (- 0.06 to 0.67)) and (0.60 (0.10 to 0.80)) at 1- and 4-month post-fracture, respectively.

CONCLUSIONS

Hip fracture results in a large decline in the ability to perform activities of daily living and patient-reported health-related quality of life with only partial recovery amongst survivors 4-month post-fracture.

Real-world antidiabetic drug use and fracture risk in 12,277 patients with type 2 diabetes mellitus: a nested case-control study

We conducted a nested case-control study to study the association between antidiabetic treatments (alone or in combination) use and fracture risk among incident type 2 Diabetes mellitus patients. We found an increased risk of bone fracture with insulin therapy compared to metformin monotherapy.

INTRODUCTION

Patients with type 2 diabetes mellitus (T2DM) have an increased risk of fragility fractures, to which antidiabetic therapies may contribute. We aimed to characterize the risk of fracture associated with different antidiabetic treatments as usually prescribed to T2DM patients in actual practice conditions.

METHODS

A case-control study was nested within a cohort of incident T2DM patients registered in 2006-2012 in the Information System for Research Development in Primary Care (Catalan acronym, SIDIAP), a database which includes records for > 5.5 million patients in Catalonia (Spain). Each case (incident major osteoporotic fracture) was risk-set matched with up to five same-sex controls by calendar year of T2DM diagnosis and year of birth (± 10 years). Study exposure included previous use of all antidiabetic medications (alone or in combination), as dispensed in the 6 months before the index date, with metformin (MTF) monotherapy, the most commonly used drug, as a reference group (active comparator).

RESULTS

Data on 12,277 T2DM patients (2049 cases and 10,228 controls) were analyzed. Insulin use was associated with increased fracture risk (adjusted OR 1.63 (95% CI 1.30-2.04)), as was the combination of MTF and sulfonylurea (SU) (adjusted OR 1.29 (1.07-1.56)), compared with MTF monotherapy. Sensitivity analyses suggest possible causality for insulin therapy but not for the MTF + SU combination association. No significant association was found with any other antidiabetic medications.

CONCLUSIONS

Insulin monotherapy was associated with an increased fracture risk compared to MTF monotherapy in T2DM patients. Fracture risk should be taken into account when starting a glucose-lowering drug as part of T2DM treatment.

In-vitro study of hierarchical structures: Anodic oxidation and alkaline treatments onto highly rough titanium cold gas spray coatings for biomedical applications

Hierarchical structures were obtained applying two different nanotexturing surface treatments onto highly rough commercial pure titanium coatings by cold spray: (i) anodic oxidation and (ii) alkaline treatments. An extended surface characterization in terms of topography, composition, and wettability has been performed to understand how those parameters affect to cell response. Primary human osteoblasts extracted from knee were seeded onto the as-sprayed titanium surface before and after the nanotexturing treatments. Cell viability was tested by using MTS and LIVE/DEAD assays, as well as osteoblasts differentiation by alkaline phosphatase (ALP) quantification at 3 and 10 days of cell culture. The combination of micro-/nano-roughness results in a significantly increase of cell proliferation, as well as cell differentiation after 10 days of cell culture in comparison with the non-treated coatings.

Osteoblastic cell response on high-rough titanium coatings by cold spray

Highly rough and porous commercially pure titanium coatings have been directly produced for first time by the cold spray technology, which is a promising technology in front of the vacuum plasma spray for oxygen sensitive materials. The wettability properties as well as the biocompatibility evaluation have been compared to a simply sand blasted Ti6Al4V alloy substrate. Surface topographies were analysed using confocal microscopy. Next, osteoblast morphology (Phalloidin staining), proliferation (MTS assay), and differentiation (alkaline phosphatase activity) were examined along 1, 7 and 14 days of cell culture on the different surfaces. Finally, mineralization by alizarin red staining was quantified at 28 days of cell culture. The contact angle values showed an increased hydrophilic behaviour on the as-sprayed surface with a good correlation to the biological response. A higher cell viability, proliferation and differentiation were obtained for highly rough commercial pure titanium coatings in comparison with sand blasted substrates. Cell morphology was similar in all coatings tested; at 14 days both samples showed extended filopodia. A higher amount of calcium-rich deposits was detected on highly rough surfaces. In summary, in-vitro results showed an increase of biological properties when surface roughness increases.

Spanish consensus on treat to target for osteoporosis

To reach a Spanish expert consensus on a treat-to-target strategy in osteoporosis, a Delphi Consensus Study has been developed. Most of the experts (59.8%) were rheumatologist with a mean clinical experience of 21.3 years (SD 8.5). Consensus was achieved for 70% of the items. Therapeutic objectives, patient follow-up scheme, treatment failure criteria, and appropriate treatment choice for use in T2T strategy in Spain have been defined.

INTRODUCTION

The paper aims to achieve a Spanish expert consensus on a treat-to-target (T2T) strategy in osteoporosis.

METHODS

A scientific committee led the project and was involved in expert panel identification and Delphi questionnaire development. Two Delphi rounds were completed. The first-round questionnaire included 24 items and assessed, using a seven-point Likert scale, the experts' wish (W) and prognosis (P) in 5 years for each topic (applicability, therapeutic objectives, patient follow-up, and possible treatment to be prescribed). Items for which there was no consensus in the first round were included in the second round. Consensus was defined as ≥75% agreement (somewhat/mostly/entirely agree) or disagreement (somewhat/mostly/entirely disagree) responses.

RESULTS

Of the experts, 112 and 106 completed the first and second rounds, respectively. 59.8% were rheumatologists with a mean clinical experience of 21.3 years (SD 8.5). Consensus was achieved for 70% of the items, and was established regarding the utility of a T2T strategy to define therapeutic objectives, optimal follow-up, and therapeutic algorithm. Participants agreed on the utility of the bone mineral density (BMD) value (T-score >-2.5 SD for spine and >-2.5/-2.0 SD for femoral neck), lack of fractures, and fracture risk (FRAX) as therapeutic objectives. For measuring BMD changes, consensus was achieved on the suitability of hip and femoral neck locations. Experts agreed to consider treatment failure as when a significant BMD gain could not be achieved, or when a new fracture occurs within 2-3 years. There was consensus that all proposed therapies should achieve a therapeutic target through T2T strategy (treatments with the highest consensus scores were denosumab and teriparatide).

CONCLUSION

The therapeutic objectives, patient follow-up scheme, treatment failure criteria, and appropriate treatment choice for use in T2T strategy in Spain have been established by a panel of experts. Some aspects nevertheless still require further analysis.

Discrepancy between bone density and bone material strength index in three siblings with Camurati-Engelmann disease

Camurati-Engelmann (CE) is a very rare disease affecting one in every million persons worldwide. It is characterized by an enlargement of long bones. We aimed to assess bone characteristics in three siblings with different tools. Even if there was an excess of bone density, quality seemed to be deteriorated.

INTRODUCTION

CE disease is a rare monogenic disorder affecting approximately one in every million persons worldwide. It is mainly characterized by a progressive hyperostosis of the periosteum and endosteum of the diaphysis of long bones. Limited data are available about bone characteristics in these patients. In three siblings with CE disease, we aimed to assess bone mineral density (BMD) and trabecular bone score (TBS) by dual-energy X-ray absorptiometry (DXA) and material characteristics at tissue level using bone impact reference point indentation.

METHODS

Clinical data were collected and a general laboratory workup was performed. At the lumbar spine and hip, BMD and TBS were measured using DXA imaging. Bone material strength index (BMSi) was measured by bone impact microindentation using an Osteoprobe instrument.

RESULTS

All three cases had densitometric values consistent with high bone mass (sum of Z-score at the lumbar spine and hip > 4). Hip BMD was extremely high in all three siblings at both total hip and femoral neck, while at the lumbar spine, two of them had normal values but the third again had very high BMD. TBS values were in the normal range. In contrast, BMSi measurements were at low or very low levels, compared with normal controls.

CONCLUSION

Despite strikingly increased BMD and normal microarchitecture, BMSi is affected in patients with CE. Microindentation could be an appropriate tool for assessing bone fragility in these patients. Bone disease in this group of patients requires further study to better understand the underlying regulatory mechanisms and their alterations.

Bone density, microarchitecture, and material strength in chronic kidney disease patients at the time of kidney transplantation

Bone health is assessed by bone mineral density (BMD). Other techniques such as trabecular bone score and microindentation could improve the risk of fracture's estimation. Our chronic kidney disease (CKD) patients presented worse bone health (density, microarchitecture, mechanical properties) than controls. More than BMD should be done to evaluate patients at risk of fracture.

INTRODUCTION

BMD measured by dual-energy X-ray absorptiometry (DXA) is used to assess bone health in end-stage renal disease (ESRD) patients. Recently, trabecular bone score (TBS) and microindentation that can measure microarchitectural and mechanical properties of bone have demonstrated better correlation with fractures than DXA in different populations. We aimed to characterize bone health (BMD, TBS, and strength) and calcium/phosphate metabolism in a cohort of 53 ESRD patients undergoing kidney transplantation (KT) and 94 controls with normal renal function.

METHODS

Laboratory workout, lumbar spine/hip BMD measurements (using DXA), lumbar spine TBS, and bone strength were carried out. The latter was assessed with an impact microindentation device, standardized as percentage of a reference value, and expressed as bone material strength index (BMSi) units. Multivariable linear regression was used to study differences between cases and controls adjusted by age, gender, and body mass index.

RESULTS

Among cases, serum calcium was 9.6 ± 0.7 mg/dl, phosphorus 4.4 ± 1.2 mg/dl, and intact parathyroid hormone 214 pg/ml [102-390]. Fourteen patients (26.4%) had prevalent asymptomatic fractures in spinal X-ray. BMD was significantly lower among ESRD patients compared to controls: lumbar 0.966 ± 0.15 vs 0.982 ± 0.15 (adjusted p = 0.037), total hip 0.852 ± 0.15 vs 0.902 ± 0.13 (adjusted p < 0.001), and femoral neck 0.733 ± 0.15 vs 0.775 ± 0.12 (adjusted p < 0.001), as were TBS (1.20 [1.11-1.30] vs 1.31 [1.19-1.43] (adjusted p < 0.001)) and BMSi (79 [71.8-84.2] vs 82. [77.5-88.9] (adjusted p = 0.005)).

CONCLUSIONS

ESRD patients undergoing transplant surgery have damaged bone health parameters (density, microarchitecture, and mechanical properties) despite acceptably controlled hyperparathyroidism. Detecting these abnormalities may assist in identifying patients at high risk of post-transplantation fractures.

Clinical practice guidelines for posmenopausal, glucocorticoid-induced and male osteoporosis. Spanish Society for Research on Bone and Mineral Metabolism (3rd updated version 2014)

These guidelines update issues covered in previous versions and introduce new ones that have arisen in recent years. The former refer mainly to the therapeutic developments that have been made during this time (zoledronate, denosumab, bazedoxifene), which have led to a change in the drug selection algorithm. The latter deal with therapeutic management, the description of new adverse effects (which have led to changes in therapeutic behaviour patterns, as is the case with atypical fracture of the femur), treatment duration (with consideration for the so-called "therapeutic holidays"), the so-called sequential treatment and changes in treatment imposed by certain circumstances. A new algorithm has been introduced for sequential treatment. Attention has also been paid to vertebroplasty and kyphoplasty.

CYP11A1 expression in bone is associated with aromatase inhibitor-related bone loss

Aromatase inhibitors (AIs) used as adjuvant therapy in postmenopausal women with hormone receptor-positive breast cancer cause diverse musculoskeletal side effects that include bone loss and its associated fracture. About half of the 391 patients treated with AIs in the Barcelona-Aromatase induced bone loss in early breast cancer cohort suffered a significant bone loss at lumbar spine (LS) and/or femoral neck (FN) after 2 years on AI-treatment. In contrast, up to one-third (19.6% LS, 38.6% FN) showed no decline or even increased bone density. The present study aimed to determine the genetic basis for this variability. SNPs in candidate genes involved in vitamin D and estrogen hormone-response pathways (CYP11A1, CYP17A1, HSD3B2, HSD17B3, CYP19A1, CYP2C19, CYP2C9, ESR1, DHCR7, GC, CYP2R1, CYP27B1, VDR and CYP24A1) were genotyped for association analysis with AI-related bone loss (AIBL). After multiple testing correction, 3 tag-SNPs (rs4077581, s11632698 and rs900798) located in the CYP11A1 gene were significantly associated (P<0.005) with FN AIBL at 2 years of treatment. Next, CYP11A1 expression in human fresh bone tissue and primary osteoblasts was demonstrated by RT-PCR. Both common isoforms of human cholesterol side-chain cleavage enzyme (encoded by CYP11A1 gene) were detected in osteoblasts by western blot. In conclusion, the genetic association of CYP11A1 gene with AIBL and its expression in bone tissue reveals a potential local function of this enzyme in bone metabolism regulation, offering a new vision of the steroidogenic ability of this tissue and new understanding of AI-induced bone loss.

The impact of common co-morbidities (as measured using the Charlson index) on hip fracture risk in elderly men: a population-based cohort study

We used a large population-based health care database to determine the impact of common co-morbidities on hip fracture risk amongst elderly men. We demonstrated that diabetes, chronic obstructive pulmonary disease, renal failure, HIV infection, dementia, and cerebrovascular disease are independent predictors of hip fracture, as is a Charlson score of ≥ 3.

INTRODUCTION

Risk factors for hip fractures in men are still unclear. We aimed to identify common co-morbidities (amongst those in the Charlson index) that confer an increased risk of hip fracture amongst elderly men.

METHODS

We conducted a population-based cohort study using data from the SIDIAP (Q) database. SIDIAP(Q) contains primary care and hospital inpatient records of a representative 30% of the population of Catalonia, Spain (>2 million people). All men aged ≥ 65 years registered on 1 January 2007 were followed up until 31 December 2009. Both exposure (co-morbidities in the Charlson index) and outcome (incident hip fractures) were ascertained using ICD codes. Poisson regression models were fitted to estimate the effect of (1) each individual co-morbidity and (2) the composite Charlson index score, on hip fracture risk, after adjustment for age, body mass index, smoking, alcohol drinking, and use of oral glucocorticoids.

RESULTS

We observed 186,171 men for a median (inter-quartile range) of 2.99 (2.37-2.99) years. In this time, 1,718 (0.92%) participants had a hip fracture. The following co-morbidities were independently associated with hip fractures: diabetes mellitus, chronic obstructive pulmonary disease (COPD), renal failure, HIV infection, dementia, and cerebrovascular disease. A Charlson score of ≥ 3 conferred an increased hip fracture risk.

CONCLUSION

Common co-morbidities including diabetes, COPD, cerebrovascular disease, renal failure, and HIV infection are independently associated with an increased risk of hip fracture in elderly men. A Charlson score of 3 or more is associated with a 50% higher risk of hip fracture in this population.

Burden of pelvis fracture: a population-based study of incidence, hospitalisation and mortality

The objective of this study was to describe the incidence and consequences of pelvic fractures in a community cohort. The incidence of pelvic fractures increases with age with a protective effect of higher body mass index. Almost 60% of those with a pelvic fracture required an inpatient stay, with a median of 9 days. There was a higher 3-year mortality in those admitted (17%) vs. those not admitted (6.3%). Given the substantial health burden, further work is required to identify the optimal post-fracture therapeutic strategy to improve outcomes.

INTRODUCTION

The burden of pelvis fractures is projected to increase, but there is a paucity of community-based studies describing rates, mortality and future fracture risk. We therefore estimated the age, gender and BMI-specific incidence of pelvis fracture in Catalonia (North-East Spain), and assessed hospital stay and mortality following fracture.

METHODS

The SIDIAP(Q) database contains validated clinical information from computerised medical records of a representative sample of 30% of the population of Catalonia. We conducted a retrospective cohort study including all subjects aged ≥ 40 in SIDIAP(Q) and linked to the regional Hospital Admissions Database from 2007 to 2009. Pelvis fractures were ascertained using ICD-10 codes. Incidence and mortality rates were calculated.

RESULTS

A total of 1,118,173 patients (582,820 women) were observed for 3 years and 1,356 had a pelvic fracture. The rate for pelvic fracture was 4.35/10,000 person-years (pyar) [95% CI 4.13-4.59] (men-2.73 [2.48-3.01]; women-5.82 [5.46-6.20]). This increased with age, peaking in those over 90 years: 29.41 [25.74-33.59]. Higher BMI was protective (HR 0.75 per SD BMI; [0.69-0.82]). Moreover, 59.1% of fractured patients were hospitalised with a median (IQR) stay of 9 (5-16) days, and after the 3-year follow-up 13.9% died (mortality rate 10.7/100 pyar [9.3-12.3]) with higher rates in those hospitalised (17.0%).

CONCLUSIONS

Pelvic fractures are associated with high rates of hospitalisation and mortality. Given this, further work is required to identify the optimal post-fracture therapeutic strategy to improve outcomes in this elderly patient group.

Alterations of the Wnt/beta-catenin pathway and its target genes for the N- and C-terminal domains of parathyroid hormone-related protein in bone from diabetic mice

Type 1 diabetes mellitus (T1D) is associated with bone loss. Given that the Wnt/beta-catenin pathway is a major regulator of bone accrual, we assessed this pathway in mice with streptozotozin-induced T1D. In diabetic mouse long bones, we found alterations favouring the suppression of this pathway by using PCR arrays and beta-catenin immunostaining. Downregulation of sclerostin, an inhibitor of this pathway, also occurred, and related to increased osteocyte apoptosis. Our data show that both N- and C-terminal parathyroid hormone-related peptide fragments might exert osteogenic effects in this setting by targeting several genes of this pathway and increasing beta-catenin in osteoblastic cells.

Effect of parathyroidectomy for primary hyperparathyroidism on bone mineral density in postmenopausal women

Background

The bone mineral density (BMD) response to parathyroidectomy is heterogeneous and difficult to predict. Available data come from mixed populations of men and women, of different age and degrees of disease severity, and preoperative BMD loss.

Methods

This was a longitudinal, prospective cohort study of 103 postmenopausal women with osteopenia or osteoporosis at the femoral neck site, successfully operated on for primary hyper parathyroidism. BMD and metabolic variables were recorded before and 1 year after parathyroidectomy.

Results

After surgery, there was a 1·3 per cent increase in the median BMD at the femoral neck site (0·615 versus 0·623 g/cm2; P = 0·001). Overall, positive responses were also observed at total hip (0·4 per cent) and lumbar spine (2·3 per cent) sites. Analysing the individual responses, however, only 45 (46 per cent) of 97 patients showed a significant (at least 3·7 per cent) increase in BMD at the femoral neck site compared with the preoperative value and 52 had a decreased (15) or unchanged (37) femoral neck BMD. Patients who gained BMD were younger, had more severe hyperparathyroidism and better renal function.

Conclusion

Almost half of the postmenopausal women with hyperparathyroidism and low BMD have a significant remineralization response 1 year after parathyroidectomy. Differential mineralization responses of BMD after surgery appear to be related to severity of primary hyperparathyroidism, age and renal function.

Polymorphisms and haplotypes across the osteoprotegerin gene associated with bone mineral density and osteoporotic fractures

Osteoprotegerin plays a key role in bone remodelling. We studied the association between 24 polymorphisms and haplotypes on the OPG gene and bone mineral density and fractures. After multiple-testing correction, one SNP and two block-haplotypes were significantly associated with FN BMD. Two other block-haplotypes were associated with fracture.

INTRODUCTION AND HYPOTHESIS

Osteoprotegerin (OPG) plays a key role in bone remodelling. Here we studied the association between polymorphisms and haplotypes on the OPG gene and bone mineral density (BMD) and fractures.

METHODS

Twenty-four single nucleotide polymorphisms (SNPs) were selected to cover six haplotypic blocks and were genotyped in 964 postmenopausal Spanish women. Haplotypes were established with HaploStats. Association was analysed by GLM (for BMD) and logistic regression (for fractures) both at single SNP and haplotype levels.

RESULTS

Upon adjustment for multiple testing (p < 0.0073), one of the SNPs (SNP #17, rs1032129) remained significantly associated with FN BMD (p = 0.001). Four block-haplotypes stood multiple-testing correction. Two remained associated with FN BMD and two with fracture. The association of block-4 haplotype "AC" (of SNPs #18 and #17) with FN BMD (p = 0.0002) was stronger than that of SNP#17 alone and was the best result overall. A global assessment of the results indicated that all the alleles and haplotypes with a protective effect, at p < 0.05, belonged to a frequent long-range haplotype.

CONCLUSIONS

In conclusion, these results provide a detailed picture of the involvement of common variants and haplotypes of the OPG gene in bone phenotypes.

A porous PCL scaffold promotes the human chondrocytes redifferentiation and hyaline-specific extracellular matrix protein synthesis

The redifferentiation, proliferation, and hyaline-specific extracellular matrix (ECM) protein synthesis of chondrocytes cultured in a polycaprolactone (PCL) scaffold were analyzed. Gene expression of the type II collagen and aggrecan was assessed by real-time PCR in cells from PCL scaffolds, monolayer, and pellet cultures. The proliferative activity was assessed using Ki-67 immunodetection, and the chondrocytic differentiation was evaluated using S-100 immunodetection. The synthesis and deposition into scaffold pores of type II collagen and glycosaminoglycan were analyzed by immunohistochemistry and Alcian blue staining, respectively. All parameters were assessed throughout 28 days of cultures maintained in either fetal bovine serum-containing medium (FCM) or Insulin-Transferrin-Selenium-containing medium (ICM). Expression of the type II collagen gene was lower in FCM cultures than in ICM cultures for all culture systems (p < 0.05). Moreover, PCL scaffolds cultured in ICM were able to induce collagen gene expression more efficiently than pellet and monolayer cultures. Aggrecan gene expression did not vary significantly between mediums and three-dimensional system cultures, but in ICM cultures, the monolayer cultures had significantly higher levels of aggrecan gene expression than did either the PCL or pellet cultures. Chondrocytes cultured in PCL scaffolds or pellets with FCM did not proliferate to a great extent but did maintain their differentiated phenotype for 28 days. Levels of cartilage ECM protein synthesis and deposition into the scaffold pores were similar among PCL and pellet cultures grown in FCM and in ICM. In conclusion, chondrocytes seeded into PCL scaffolds, cultured in ICM, efficiently maintained their differentiated phenotype and were able to synthesize cartilage-specific ECM proteins.

Polymorphisms in the interleukin-6 receptor gene are associated with bone mineral density and body mass index in Spanish postmenopausal women

OBJECTIVE

Osteoporosis and obesity are complex diseases with a strong genetic component. Bone mineral density (BMD) and body mass index (BMI) linkage studies identified a locus at 1q21-23, where the interleukin-6 receptor (IL6R) gene is located. The IL6R and the gp130 receptors are the mediators of IL6 action. Serum levels of IL6 and sIL6R (the soluble form of IL6R) are higher in several diseases such as osteoporosis or obesity. Variants at IL6R have been associated with BMI and obesity. However, IL6R is an as-yet-unexplored osteoporosis candidate gene.

DESIGN

In the present study we analysed two polymorphisms in the IL6R promoter, -1435 C/T (rs3887104) and -208 G/A (rs4845617), and the Asp358Ala polymorphism (rs8192284), in relation to both BMD and BMI in a cohort of 559 postmenopausal Spanish women.

RESULTS

The promoter polymorphisms, -1435 C/T and -208 G/A were associated with femoral neck (FN) BMD (P=0.011 and P=0.025 respectively). The C-A and T-G promoter haplotypes were also associated with FN BMD. Additionally, the Asp358Ala variant was associated with lumbar spine BMD (P=0.038). Finally, the -208 G/A polymorphism and the C-G and C-A haplotypes were associated with BMI and obesity, where GG was the risk genotype (P=0.033 for BMI; P=0.010 for obesity).

CONCLUSION

These data suggest that variants in the IL6R gene are not only involved in the determination of BMI but also relevant for the determination of BMD. The IL6R gene may belong to the growing list of genes known to be involved in both phenotypes.

COL1A1, ESR1, VDR and TGFB1 polymorphisms and haplotypes in relation to BMD in Spanish postmenopausal women

INTRODUCTION AND HYPOTHESIS

Genetic studies of osteoporosis have focused on analysing single polymorphisms in individual genes - with inconclusive results. An alternative approach may involve haplotypes and gene-gene interactions. The aim of the study was to test the association between the COL1A1, ESR1, VDR and TGFB1 polymorphisms or haplotypes and bone mineral density (BMD) in Spanish postmenopausal women.

METHODS

Sixteen polymorphisms were analysed in 719 postmenopausal women. ANOVA, ANCOVA and Xi2 tests were used to perform the statistical analysis.

RESULTS

COL1A1 -1997G > T (p=0.04) and TGFB1 Leu10Pro (p=0.02) were found to be associated with adjusted lumbar spine (LS) BMD. Interactions were observed between: the COL1A1 -1997 G/T and Sp1 polymorphisms (p < 0.01 for LS BMD) and the COL1A1 -1663 indelT and VDR ApaI polymorphisms (p < 0.01 for femoral neck (FN) BMD). The COL1A1 GDs and ESR1 LPX haplotypes were associated with FN BMD (p=0.03 and p=0.03).

CONCLUSIONS

Polymorphisms at COL1A1 and TGFB1 and haplotypes at COL1A1 and ESR1 were found to be associated with BMD in a cohort of postmenopausal Spanish women. Moreover, COL1A1 polymorphisms showed significant interactions among them and with the VDR 3' polymorphisms.

Effect of smoking and smoking cessation on bone mass, bone remodeling, vitamin D, PTH and sex hormones

OBJECTIVE

To assess the effect of smoking and smoking cessation on bone density, bone remodeling markers, sex hormones, and vitamin D-PTH axis in healthy young subjects.

MATERIALS AND METHODS

We studied 74 healthy people (31 men, 43 women; mean age 32.2 (7) years) divided into 52 never smokers and 22 smokers, 15 of which stopped smoking for one month.

RESULTS

Male smokers compared with never smokers showed lower BMD (0.971 (0.11) g/cm(2) vs. 1.069 (0.09) g/cm(2), P=0.042); higher plasma estrone levels (32.37 (10.13) pg/mL vs. 20.91 (5.46) pg/mL, P=0.001); and lower serum iPTH levels (16.2 (3.5) pg/mL vs. 28.8 (2.0) pg/mL, P=0.008). In women, BMD values were similar in smokers than in never smokers, but 25-hydroxyvitamin D levels were lower in smokers (31.9 (15.1) ng/mL vs. 16.8 (9.9) ng/mL, P=0.002). After adjusting by age and coffee consumption, female smokers had higher urinary-NTX levels than never smokers. After smoking cessation, statistically significant decreases of 25-hydroxyvitamin D and SHBG plasma levels were observed in men and women, respectively.

CONCLUSIONS

Tobacco increases bone resorption and affects bone mass by some alterations in sex hormone metabolism, but also importantly by alterations on the vitamin D-PTH axis.

Inhaled steroids do not decrease bone mineral density but increase risk of fractures: data from the GIUMO Study Group

Although the negative effect of systemic steroids on bone is well documented, there is not clear evidence about possible adverse effects of inhaled steroids on bone metabolism and fractures. A cross-sectional study was performed on 105 women suffering from bronchial asthma treated with inhaled steroids and 133 controls. Bone mineral density (BMD) was measured by quantitative ultrasonography (QUS) at the calcaneus and by dual X-ray absorptiometry (DXA), at both the lumbar spine and proximal femur. Patients suffering from bronchial asthma showed no statistically significant changes in BMD as measured by DXA or QUS, compared with controls. A higher prevalence of fractures was found in the group of women with bronchial asthma, with an age-adjusted odds ratio of 2.79 (95% CI: 1.19-6.54). Inhaled steroids do not appear to decrease BMD, but are associated with an increased risk of fracture in women.

Timing of follow-up densitometry in hormone replacement therapy users for optimal osteoporosis prevention

The objectives of the study were (1) to determine the time interval for repeat dual-energy X-ray absorptiometry (DXA) to detect significant bone loss, i.e., greater than the coefficient of variation (CV) of the center (2.8 x CV%) and (2) to assess how long hormone replacement therapy can be maintained to avoid undetected development of low bone mass and to not unduly delay appropriate treatment. A total of 3,826 healthy women, aged 40-65 years, participated in a prospective cohort study, 807 of whom were treated with transdermal estrogen replacement therapy and 626 with transdermal estrogen/progesterone regimens. The untreated group included the remaining 2,393 women. Between 1996 and 2002 they underwent a baseline DXA scan, and DXA scans were then repeated annually. There were no differences among the study groups at entry into the study. Treatment with estrogen was a protective factor for loss of bone mass at the lumbar spine (odds ratio [OR] =0.431, 95% confidence interval [CI] 0.344 to 0.522) and at the femoral neck (OR =0.433, 95% CI 0.352 to 0.521). Treatment with estrogen/progesterone also showed a protective effect against significant changes in follow-up BMD (>2.8 x 1.05% CV of densitometry at L1-L4, >2.8 x 2.3% CV at the femoral neck). In the treated group, significant differences in BMD at the lumbar spine (OR =1.593, 95% CI 1.423 to 2.355) did not appear within the first 3 years, and differences in BMD at the femoral neck (OR =3.555, 95% CI 2.782 to 4.905) did not appear within the first 4 years. It is concluded that in women aged 45-65 years, receiving transdermal hormone replacement therapy without risk factor for loss of bone mass, such as age < 55 years and body mass index <25 kg/m(2), periodical follow-up densitometries would not be necessary, provided that the duration of estrogen or estrogen/progesterone therapy is shorter than 3 years.

Relationship among densitometry, bone histomorphometry, and histologic stage in idiopathic myelofibrosis

Idiopathic myelofibrosis (IMF) induces dramatic changes in bone. Bone remodeling and densitometric alterations in a series of nine patients with IMF and their relationship with the histologic stage of the disease were assessed. Patients were included at diagnosis and a bone marrow biopsy, dual-energy X-ray absorptiometry, and transiliac bone biopsy for histomorphometric analysis were performed. Five cases were classified as IMF histologic stage 1, one as stage 2, and three as stage 3. Compared with 40 age- and sex-matched controls, the following histomorphometric parameters were significantly higher in our patients: bone volume (BV/TV), osteoblast surface (Ob.S/BS), eroded surface (ES/BS), osteoclast surface (Oc.S/BS), osteoclast number (N.Oc/TA), mineralizing surface (MS/BS), reversal period (Rv.P), and remodeling period (Rm.P). Mineral apposition rate (MAR) and erosion depth (E.Depth) were significantly decreased (P < 0.05 for all comparisons). Bone mineral density (BMD) measurements showed high values for patient age and sex both at femur neck (Z score range +0.19 to +7) and total femur (Z score range -0.09 to +6.48). When densitometric values were analyzed according to IMF histologic stage, patients in stages 1 and 2 had significantly lower BMD values than to those in stage 3 (P = 0.024). In conclusion, patients with IMF present a characteristic bone histomorphometric pattern with increased bone volume and bone cells but low apposition and decreased erosion depth, suggesting a positive balance in bone remodeling units. This balance would produce the increase in bone mass observed in this disease. Given the increase in BMD observed with more advanced stages of IMF, this noninvasive method could be useful tool for assessing IMF progression.

Alendronate and etidronate do not regulate interleukin 6 and 11 synthesis in normal human osteoblasts in culture

Bisphosphonates exert a potent inhibitory effect on bone resorption. Several studies have been performed, with contradictory results, to ascertain whether the effect of bisphosphonates on osteoclasts could be produced, at least in part, by modulation of the synthesis of resorption-promoting factors by osteoblasts. The aim of this study was to evaluate the effect of etidronate (10-4-10-9 M) and alendronate (10-7-10-12 M) on the production of IL-6 and IL-11 using human osteoblast cultures. Cytokines were quantified by ELISA, and mRNA expression was tested. Treatment with alendronate and etidronate had no effect on the synthesis of IL-6 or IL-11, and IL-6 and IL-11 mRNA levels. These results were obtained both in nonstimulated cultures and in cultures stimulated by means of TNF-a, IL-1b, and TNF-a+IL-1b, with or without FCS. In conclusion, a possible indirect osteoclast-mediated effect of alendronate and etidronate on bone resorption would not be exerted through reduction in osteoblastic synthesis of IL-6 and IL-11.

Effect of alendronate on cultured normal human osteoblasts

Alendronate is an aminobisphosphonate with a potent anti-reabsorptive action that does not appear to interfere with bone mineralization, and is even able to increase bone mineral density in osteoporotic postmenopausal women through a still not fully understood mechanism. This study was conducted to assess the direct effect of alendronate on diverse aspects of normal human osteoblast physiology. For that purpose, the in vitro effect of a wide range of concentrations [from 10(-1) to 10(-12) mol/L] of alendronate on cell viability, proliferation, collagen synthesis, and the mineral-depositing capacity of normal human osteoblasts was tested. Alendronate effects were examined at 48 and 96 h of culture in the presence or absence of fetal calf serum. In vitro alendronate affected osteoblast viability at concentrations equal to or higher than 10(-4) mol/L. At concentrations equal to or higher than 10(-3) mol/L, no viable cells were observed in cultures. In vitro alendronate at concentrations between 10(-5) and 10(-12) mol/L did not have any effect on the proliferative capacity of normal human osteoblasts determined by two different techniques: (1) tritiated thymidine incorporation to DNA and (2) cell counting. Collagen synthesis by normal human osteoblasts showed a tendency to decrease following incubation with alendronate supplemented with fetal calf serum. This decrease was only statistically significant after 96 h of culture; however, a dose-response effect could not be documented. Finally, no effect of alendronate was observed on calcium deposition in vitro by normal human osteoblasts at concentrations equal to or lower than 10(-5) mol/L. In conclusion, the present study shows that alendronate in vitro does not affect viability, proliferation, and mineral deposit capacity of normal human osteoblasts at the concentration at which it inhibits by 50% the resorptive capacity of osteoclasts that for this drug has been reported as 2 x 10(-9) mol/L.