Bone turnover markers as determinants of bone density and fracture in men with distal forearm fractures: the pathogenesis examined in the Mr F study.

The pathogenesis for low-trauma wrist fractures in men is not fully understood. This study found that these men had evidence of significantly higher bone turnover compared with control subjects. Bone turnover markers were negative predictors of bone mineral density and were a predictor of fracture. INTRODUCTION: Men with distal forearm fractures have reduced bone density, an increased risk of osteoporosis and of further fractures. The aim of this study was to investigate whether or not men with distal forearm fractures had evidence of altered bone turnover activity. METHODS: Fifty eight men with low-trauma distal forearm fracture and 58 age-matched healthy control subjects were recruited. All subjects underwent a DXA scan of the forearm, both hips, and lumbar spine, biochemical investigations, and health questionnaires. Measurements of beta crosslaps (ßCTX), procollagen type I N-terminal propeptide (PINP), sclerostin, Dickkopf-1 (Dkk1), and fibroblast growth factor 23 (FGF 23) were made. RESULTS: Men with fracture had significantly higher PINP than controls at 39.2 ng/ml (SD 19.5) versus 33.4 ng/ml (SD13.1) (p<0.001). They also had significantly higher ßCTX at 0.45 ng/ml (SD 0.21) versus 0.37 ng/ml (SD 0.17) (p= 0.037). Fracture subjects had significantly lower aBMD and PINP was a negative predictor of aBMD at the total hip and ßCTX a negative predictor of forearm aBMD. Sclerostin was a positive predictor of aBMD at the lumbar spine and hip sites. Sex hormone binding globulin (SHBG) at 37nmol/L (SD 15.0) was lower in fracture cohort compared to 47.9 nmol/L (SD 19.2) (p=0.001) in control. Multiple regression revealed that the best model for prediction of fracture included SHBG, P1NP, and ultra-distal forearm aBMD. The likelihood of distal forearm fracture was decreased by 5.1% for each nmol/L increase in SHBH and by 1.4% for every mg/cm2 increase in ultra-distal forearm aBMD, but increased by 6.1 % for every ng/ml increase in P1NP. Men in the highest quartile of PINP had a significantly greater likelihood of distal forearm fracture than those in the lowest quartile. CONCLUSION: The fracture group had significantly higher PINP and ßCTX compared with the control group, and these markers were negative predictors of aBMD at the total hip and forearm sites, respectively. Sclerostin was a positive predictor of the variance of spinal and hip aBMD. Likelihood of forearm fracture was best predicted by a combination of SHBG, PINP, and ultra-distal forearm aBMD. Findings of such cross-sectional data should be treated with caution, as longitudinal studies would be required to confirm or refute them.

Long-term evaluation of anabolic and anti-resorptive agents in adults with familial osteoporosis due to pro205ala variant of the col1a1 gene.

INTRODUCTION: Osteogenesis imperfecta (OI) is a rare disorder with variable clinical presentation, commonly caused by mutations in collagen type I genes. OI affects both bone quality and density resulting in fractures and deformity. The effectiveness of bisphosphonates in the treatment of adult OI remains unclear. Small, randomised trials have shown increases in BMD, but without fracture rate reduction. AIM: We report the results of BMD of a family harbouring C 613 C>G substitution in exon 8 of Col1A1 gene leading to Pro205Ala missense variant, as well as the results of long term treatment of a mother and daughter with this mutation.

Obesity, bone density relative to body weight and prevalent vertebral fracture at age 62 years: the Newcastle thousand families study.

Obesity increases the likelihood of prevalent vertebral fracture (VF) in men and women at age 62 years. The higher absolute bone mineral density (BMD) observed in obese individuals is disproportionate to body weight, and this may partly explain the greater prevalence of VF in this group. INTRODUCTION: Obesity is a global epidemic, and there remains uncertainty over the effect of obesity on skeletal health, particularly in the context of osteoporosis. The aim of this study was to investigate associations of body mass index (BMI) and obesity with BMD and prevalent VF in men and women aged 62 years. METHODS: Three hundred and forty-two men and women aged 62.5 ± 0.5 years from the Newcastle Thousand Families Study birth cohort underwent DXA evaluations of femoral neck and lumbar spine BMD and of the lateral spine for vertebral fracture assessment. RESULTS: The likelihood of prevalent VF was significantly increased in men when compared to women (OR = 2.7, p < 0.001, 95% Cl 1.7-4.4). As BMI increased in women, so did the likelihood of prevalent any-grade VF (OR = 1.09, p = 0.006, 95% CI 1.02-1.17). Compared to normal weight women, obese women were more likely to have at least one VF (OR = 2.65, p = 0.025, CI 1.13-6.20) and at least one grade 1 vertebral deformity (OR = 4.39, p = 0.005, CI 1.57-12.28). Obese men were more likely to have a grade 2 and/or grade 3 VF compared to men of normal weight (OR = 3.36, p = 0.032, CI 1.11-10.16). In men and women, BMI was negatively associated with femoral neck BMD/weight (R = - 0.65, R = - 0.66, p < 0.001) and lumbar spine BMD/weight (R = - 0.66, R - 0.60, p < 0.001). CONCLUSIONS: Obesity appears to be a risk factor for prevalent VF, and although absolute BMD is higher in obese individuals, this does not appear commensurate to their increased body weight.

Does regional loss of bone density explain low trauma distal forearm fractures in men (the Mr F study)?

The pathogenesis of low trauma wrist fractures in men is not fully understood. This study found that these men have lower bone mineral density at the forearm itself, as well as the hip and spine, and has shown that forearm bone mineral density is the best predictor of wrist fracture. INTRODUCTION: Men with distal forearm fractures have reduced bone density at the lumbar spine and hip sites, an increased risk of osteoporosis and a higher incidence of further fractures. The aim of this case-control study was to investigate whether or not there is a regional loss of bone mineral density (BMD) at the forearm between men with and without distal forearm fractures. METHODS: Sixty-one men with low trauma distal forearm fracture and 59 age-matched bone healthy control subjects were recruited. All subjects underwent a DXA scan of forearm, hip and spine, biochemical investigations, health questionnaires, SF-36v2 and Fracture Risk Assessment Tool (FRAX). The non-fractured arm was investigated in subjects with fracture and both forearms in control subjects. RESULTS: BMD was significantly lower at the ultradistal forearm in men with fracture compared to control subjects, in both the dominant (mean (SD) 0.386 g/cm2 (0.049) versus 0.436 g/cm2 (0.054), p < 0.001) and non-dominant arm (mean (SD) 0.387 g/cm2 (0.060) versus 0.432 g/cm2 (0.061), p = 0.001). Fracture subjects also had a significantly lower BMD at hip and spine sites compared with control subjects. Logistic regression analysis showed that the best predictor of forearm fracture was ultradistal forearm BMD (OR = 0.871 (0.805-0.943), p = 0.001), with the likelihood of fracture decreasing by 12.9% for every 0.01 g/cm2 increase in ultradistal forearm BMD. CONCLUSIONS: Men with low trauma distal forearm fracture have significantly lower regional BMD at the ultradistal forearm, which contributes to an increased forearm fracture risk. They also have generalised reduction in BMD, so that low trauma forearm fractures in men should be considered as indicator fractures for osteoporosis.

Femoral neck shaft angle in men with fragility fractures.

Introduction. Femoral neck shaft angle (NSA) has been reported to be an independent predictor of hip fracture risk in men. We aimed to assess the role of NSA in UK men. Methods. The NSA was measured manually from the DXA scan printout in men with hip (62, 31 femoral neck and 31 trochanteric), symptomatic vertebral (91), and distal forearm (67) fractures and 389 age-matched control subjects. Age, height, weight, and BMD (g/cm(2): lumbar spine, femoral neck, and total femur) measurements were performed. Results. There was no significant difference in mean NSA between men with femoral neck and trochanteric hip fractures, so all further analyses of hip fractures utilised the combined data. There was no difference in NSA between those with hip fractures and those without (either using the combined data or analysing trochanteric and femoral neck shaft fractures separately), nor between fracture subjects as a whole and controls. Mean NSA was smaller in those with vertebral fractures (129.2° versus 131°: P = 0.001), but larger in those with distal forearm fractures (129.8° versus 128.5°: P = 0.01). Conclusions. The conflicting results suggest that femoral NSA is not an important determinant of hip fracture risk in UK men.

Suppression of bone turnover by B-cell depletion in patients with rheumatoid arthritis.

UNLABELLED: The role of B cells in inflammatory bone formation and resorption is controversial. We investigated this in patients with rheumatoid arthritis (RA) treated with rituximab, a B-cell depleting antibody. We found a significant suppression in bone turnover, possibly a direct effect or as a consequence of a reduction in inflammation and disease activity. INTRODUCTION: RA is the most prevalent inflammatory joint disease, in which B cells play an important role. However, the role of B cells in bone turnover is controversial and RA subjects treated with rituximab, a B-cell depleting monoclonal antibody, provide an ideal model for determining the role of B cells in inflammatory bone resorption. METHODS: Serum from 46 RA patients, collected pre- and post-rituximab therapy, was analysed for biomarkers of bone turnover (procollagen type I amino-terminal propeptide [P1NP], osteocalcin, ß-isomerised carboxy-terminal telopeptide of type 1 collagen [ßCTX] and osteoprotegerin [OPG]). RESULTS: A significant decrease in bone resorption was observed 6 months after rituximab (median change ßCTX -50 ng/L, 95%CI -136, -8 p < 0.001, this equates to -37%; 95%CI -6, -49), mirrored by a reduction in disease activity. Similarly, there was a significant increase in P1NP, a marker of bone formation (median change P1NP 5.0 µg/L, 95%CI -1.0, 11.2, p = 0.02; 13%; 95%CI -3, 39), but no significant change in osteocalcin or OPG levels. The percentage change from baseline of ßCTX in a subgroup of patients (not on prednisolone or bisphosphonate) was significantly correlated with the percentage reduction in DAS28 score (r (s) = 0.570, p = 0.014). CONCLUSIONS: In conclusion, we have found that B-cell depletion increases bone formation and decreases bone resorption in RA patients; this may be a direct effect on osteoblasts and osteoclasts, respectively, and be at least partially explained by the decreased inflammation and disease activity.

Plasma vitamin D and cytokines in periodontal disease and postmenopausal osteoporosis.

BACKGROUND AND OBJECTIVE: Osteoporosis and periodontal disease are chronic diseases, in the pathogenesis of which plasma osteoprotogerin (OPG) and RANKL are important. The study aimed to investigate the relationship between periodontal disease and plasma cytokines, vitamin D and bone mineral density in postmenopausal women with and without osteoporosis. MATERIAL AND METHODS: One hundred and eighty-five postmenopausal women with osteoporosis and 185 age- and sex-matched control subjects were recruited. Periodontal disease was subdivided into active or past periodontal disease. Osteoprotegerin, RANKL, 25-hydroxyvitamin D3 (25OHD), biochemical markers of bone turnover (serum C-terminal telopeptide, CTX), anthropometry and bone mineral density were measured. RESULTS: A significantly higher proportion of the women with osteoporosis had active or past periodontal disease or both compared with control subjects (87.6 vs. 37.8%, p < 0.001). Plasma 25OHD was significantly lower (p < 0.001) and RANKL and OPG significantly higher in the women with osteoporosis than in control subjects (p < 0.0001). RANKL, OPG and CTX were significantly higher in women with active periodontal disease than in those without (p < 0.001), as were OPG and CTX in past periodontal disease (p < 0.001). In active and past periodontal disease, 25OHD was significantly lower (p < 0.001). Multiple logistic regression analysis showed that periodontal disease was best predicted by RANKL, 25OHD, C-terminal telopeptide and weight, r² = 10.4%. CONCLUSION: Periodontal disease is more common in women with osteoporosis and is associated with lower vitamin D and higher concentrations of RANKL and OPG. Raised cytokines may provide the underlying mechanism that links these two conditions.

Sex steroids and bone turnover markers in men with symptomatic vertebral fractures.

Sex steroids play an important role in the maintenance of bone density in men and women, but the circulating, biologically active unbound fraction is influenced by the concentration of sex hormone binding globulin (SHBG). SHBG increases with advancing age in men and leads to a reduction in serum free testosterone and oestradiol, which may then affect bone turnover, bone mineral density (BMD) and the risk of fractures. We have therefore measured total and unbound sex steroids, SHBG, bone turnover markers and BMD in 57 men with symptomatic low trauma vertebral fractures and 57 age-matched male control subjects. Fasting blood and urine samples were collected from all subjects, who also underwent BMD measurement of the lumbar spine and hip. Serum testosterone, oestradiol, SHBG, bone specific alkaline phosphatase (bone ALP) and urine free deoxypyridinoline/creatinine ratio (fDPD/Cr) were measured. Free sex steroid concentrations were calculated using their ratio with SHBG and albumin and bioavailable testosterone was measured using radioimmunoassay. The two groups were then compared and regression models developed to determine the best predictors of BMD and fracture. Men with vertebral fractures had significantly lower weight and BMD at all sites than control subjects (p<0.0001). Serum total testosterone and oestradiol did not differ between the two groups, but calculated free androgen and free oestradiol indices were lower in the fracture group than the control subjects (p=0.04), due to higher SHBG (46.6 versus 36.1 nmol/L: p=0.005). The men with vertebral fractures had significantly higher mean bone ALP (15.8 versus 11.8 microg/L: p=0.002) and fDPD/Cr (5.5 versus 4.0 nmol/mmol: p=0.03). Stepwise multiple regression analysis in both fracture and control groups found body weight to be the best predictor of BMD. In the fracture group weight predicted between 19.7 and 30.7% of the variance in BMD and in control subjects this was between 12.3 and 13.2%. SHBG contributed to the model for hip BMD in the fracture group alone, so that weight and SHBG together accounted for 32 to 42.9% of the variance. A model combining BMD at the spine, total femur and femoral neck with height loss best predicted fracture. In conclusion, men with symptomatic vertebral fractures have higher SHBG and lower calculated free sex steroid indices, increased bone turnover and lower BMD. Whilst body weight was the best predictor of BMD, symptomatic vertebral fracture was best predicted by BMD and height loss.

The cell biology of bone metabolism.

Contrary to the commonly held misconception, bone is a relatively dynamic organ that undergoes significant turnover as compared to other organs in the body. This review details how complex intercellular signalling, between the osteoprogenitor cells and mature osteoblasts, osteocytes and osteoclasts, regulates and balances activities of bone cells during remodelling and growth. Both systemic, as well as local autocrine and paracrine factors are discussed. A number of recent important advances in cell biology of bone have led to a new paradigm in understanding of the subject. In this regard, the interaction between the immune system and bone cells is of particular interest, leading to the emergence of a new discipline termed osteoimmunology. The role of lymphocytes and a number of key cytokines in the regulation of osteoclastogenesis and osteoblast function is critically examined. The intracellular signalling regulating key cellular pathways involved in cell differentiation and activity are outlined. The emerging evidence of osteocytes as mechanosensors as well as regulators of mineralisation is discussed.

Vitamin D-binding protein gene microsatellite polymorphism influences BMD and risk of fractures in men.

UNLABELLED: Here we report the results of a vitamin D-binding protein gene microsatellite polymorphism study in 170 men, comprising healthy male subjects and men with osteoporosis-related symptomatic vertebral fractures. We confirm the results of an earlier study in a different cohort, showing relationship between certain genotypes of (TAAAn)-Alu repeats and reduced BMD and vertebral fractures. INTRODUCTION: Vitamin D-binding protein (DBP) plays a critical role in the transport and metabolism of metabolites of vitamin D, including the key calciotropic hormone 1alpha,25-dihydroxyvitamin D3 (1,25(OH)2D3). METHODS: We have investigated intra-intronic variable tandem (TAAA)n-Alu repeat expansion in the DBP gene in 170 men, comprising healthy male subjects and men with idiopathic osteoporosis and low trauma fractures. RESULTS AND CONCLUSIONS: The predominant DBP-Alu genotype in the control subjects was 10/10 (frequency 0.421), whereas the frequency of this genotype in men with osteoporosis was 0.089. DBP-Alu alleles *10, *8 and *9, respectively, were the three commonest in both healthy subjects and men with osteoporosis. Allele *10 was associated with a lower risk of osteoporosis (OR 0.39, 95% CI 0.25-0.64; p < 0.0005), as was allele *11 (odds ratio 0.09, 95% CI 0.01-0.67; p < 0.007). Logistic regression gave similar results, showing that individuals with genotype 10/10 and 19-20 repeats (genotypes 9/10, 9/11, 10/10,) are protected from fracture or osteoporosis. Overall, there was a relationship between DBP Alu genotype and BMD, suggesting that DBP-Alu genotype may influence fracture risk. This effect may be mediated by changes in the circulating concentrations of DBP which influences free concentrations of vitamin D.

Differences in bone mineral density and geometry in men and women: the Newcastle Thousand Families Study at 50 years old.

In 1947 Sir James Spence initiated the Newcastle Thousand Families study, which recruited all 1142 children born in the city between May and June that year. At the age of 50 years, 832 survivors were traced and invited to attend for measurement of bone mineral density (BMD) by dual energy X-ray absorptiometry (DXA). The aim was to compare BMD measurements of men and women in this cohort, before and after adjustment for skeletal size. The femoral neck shaft angles (NSA) were also measured manually from the DXA scan printouts. A total of 171 men and 218 women agreed to participate. As expected men had greater bone mineral content and bone area at all sites (p<0.0001) and were taller and heavier (p<0.0001) than women. Men also had significantly higher BMD than women at all regions (p<0.0002), except at the femoral neck or lumbar spine. After correction for skeletal size and body weight, men had statistically significantly lower volumetric BMD at all sites. The measurement of NSA had good intra/interobserver errors and precision (coefficient of variations 0.79%, 1.2% and 1.2%). Men had significantly larger NSAs (mean 130 degrees , range 121-138 degrees ) than women (mean 128 degrees , range 119-137 degrees ). We conclude that there are gender differences in BMD, skeletal size and geometry in middle aged men and women, which together with the subsequent rate of bone loss, may influence fracture risk in later life.

Osteoporosis.

Osteoporosis is characterised by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and consequent increase in fracture risk. It is a common condition affecting one in three women and one in 12 men, resulting in substantial morbidity, excess mortality, and health and social services expenditure. It is therefore important to develop strategies to prevent and treat osteoporosis in both men and women. This paper reviews the pathogenesis of primary and secondary osteoporosis, as well as diagnosis, investigation, and management. This should include lifestyle changes to reduce bone loss and decrease the risk of falls, the identification and treatment of secondary causes of bone loss, and specific treatment for osteoporosis. Hormone replacement therapy, raloxifene, bisphosphonates, calcium and vitamin D, calcitonin, and parathyroid hormone have all been shown to improve bone density and decrease the risk of fracture in specific situations. It is important that treatment is tailored to the individual patient, to ensure compliance and optimise the potential benefits.

Is distal forearm fracture in men due to osteoporosis?

Although widely regarded as a disease of women, osteoporosis does cause considerable morbidity and mortality in men. The lifetime risk of an osteoporortic fracture for a man is 1 in 12 and 30% of all hip fractures occur in men. In women, low-trauma distal forearm fracture is widely regarded as a typical early manifestation of postmenopausal osteoporosis. Traditionally, this has not been thought to be the case for men. We present a case-control study of 147 men with distal forearm fracture compared with 198 age-matched controls. The controls were selected from a pre-existing database of dual-energy X-ray absorptiometry scans of healthy volunteers. Both groups were sent questionnaires regarding basic demographics, fracture history and risk factors for osteoporosis, and the fracture group was asked to attend for bone densitometry. There were 103 responses from the fracture group (70%), of whom 67 (47%) underwent densitometry. There were 165 (83%) responses from the control group. Secondary causes of osteoporosis could be identified in 51% of the fracture group and 37% of the control group. The fracture group had significantly lower bone mineral density at all sites measured compared with the controls (0.75 g/cm(2) vs 0.85 g/cm(2) at the femoral neck, p<0.0001; 0.95 g/cm(2) vs 1.03 g/cm(2) at the total femur, p = 0.001; and 0.99 g/cm(2) vs 1.06 g/cm(2) at the lumbar spine, p = 0.001). These differences remained after adjusting for age and body mass index ( p<0.0005 at all sites). Overall, 41.8% of the fracture group were osteoporotic in at least one site ( T-score <-2.5 SD below the mean for young men) compared with only 10.3% of controls. This study is the first to demonstrate that men with distal forearm fractures have lower bone mineral density than their peers and a higher risk of osteoporosis.

Characterization of the human p53 gene promoter.

Transcriptional deregulation of the p53 gene may play an important part in the genesis of some tumors. We report here an accurate determination of the transcriptional start sites of the human p53 gene and show that the majority of p53 mRNA molecules do not contain a postulated stem-loop structure at their 5' ends. Recombinant plasmids of the human p53 promoter-leader region fused to the bacterial chloramphenicol acetyltransferase gene (cat) were constructed. After transfection into rodent or human cells, a 350-base-pair fragment spanning the promoter region conferred 4% of the CAT activity mediated by the simian virus 40 early promoter/enhancer. We monitored the efficiency with which 15 3' and 5' promoter deletion constructs initiated transcription. Our results show that an 85-base-pair fragment, previously thought to have resided in exon 1, is all that is required for full promoter activity.

Overexpression of normal human p53 in established fibroblasts leads to their tumorigenic conversion.

Some, but not all, mouse p53 genes are able to cooperate with an activated ras oncogene to transform primary cells. Overexpression of what is presumed to be wild-type murine p53 is sufficient to confer a tumorigenic phenotype on established cell lines. We have investigated the effect of overexpression of normal human p53 genes on the growth and morphology of both primary and established mouse and rat cells. When plasmids containing functional human p53 genes under the control of strong viral promoter/enhancer elements were transfected into NIH3T3 cells or Rat-1 cells, no gross alterations in cell shape or morphology were observed. When stable NIH3T3 transfectants were established by co-transfection of the p53 plasmids with pSV2neo and subsequent selection in medium containing G418, many of the lines generated exhibited altered growth characteristics. While, again, the cells did not form foci above the monolayer and were not capable of growing in soft agar, they showed a reduced dependence on serum for growth, were able to grow to higher saturation densities, and displayed markedly enhanced tumorigenicity when inoculated into nude mice. The expression of human p53 in the transfectants was assessed by immunoblotting with a monoclonal antibody, PAb1801, which is reactive to human but not mouse p53. There was a clear correlation between the extent of p53 overexpression and acquisition of the tumorigenic phenotype. None of nine human p53 constructs was capable of cooperating with an activated ras oncogene to transform primary cells under conditions where a mouse clone, pLTRp53cG, could do so efficiently. None of the human p53 constructs was capable of rescuing primary rat cells from senescence. Taken together, these data show that overproduction of normal human p53 can confer an enhanced tumorigenic phenotype on established fibroblasts and support the idea that mutational activation may be necessary for p53 to express its full oncogenic potential.