Oxytocin controls differentiation of human mesenchymal stem cells and reverses osteoporosis.
Osteoporosis constitutes a major worldwide public health burden characterized by enhanced skeletal fragility. Bone metabolism is the combination of bone resorption by osteoclasts and bone formation by osteoblasts. Whereas increase in bone resorption is considered as the main contributor of bone loss that may lead to osteoporosis, this loss is accompanied by increased bone marrow adiposity. Osteoblasts and adipocytes share the same precursor cell and an inverse relationship exists between the two lineages. Therefore, identifying signaling pathways that stimulate mesenchymal stem cells osteogenesis at the expense of adipogenesis is of major importance for developing new therapeutic treatments. For this purpose, we identified by transcriptomic analysis the oxytocin receptor pathway as a potential regulator of the osteoblast/adipocyte balance of human multipotent adipose-derived stem (hMADS) cells. Both oxytocin (OT) and carbetocin (a stable OT analogue) negatively modulate adipogenesis while promoting osteogenesis in both hMADS cells and human bone marrow mesenchymal stromal cells. Consistent with these observations, ovariectomized (OVX) mice and rats, which become osteoporotic and exhibit disequilibrium of this balance, have significant decreased OT levels compared to sham-operated controls. Subcutaneous OT injection reverses bone loss in OVX mice and reduces marrow adiposity. Clinically, plasma OT levels are significantly lower in postmenopausal women developing osteoporosis than in their healthy counterparts. Taken together, these results suggest that plasma OT levels represent a novel diagnostic marker for osteoporosis and that OT administration holds promise as a potential therapy for this disease.
Elabd C, Basillais A, Beaupied H, Breuil V…
Stem Cells Sep 2008
PMID: 18583541 | Free Full Text
Oxytocin reverses osteoporosis in a sex-dependent manner.
The increase of life expectancy has led to the increase of age-related diseases such as osteoporosis. Osteoporosis is characterized by bone weakening promoting the occurrence of fractures with defective bone regeneration. Men aged over 50 have a prevalence for osteoporosis of 20%, which is related to a decline in sex hormones occurring during andropause or surgical orchidectomy. As we previously demonstrated in a mouse model for menopause in women that treatment with the neurohypophyseal peptide hormone oxytocin (OT) normalizes body weight and prevents the development of osteoporosis, herein we addressed the effects of OT in male osteoporosis. Thus, we treated orchidectomized mice, an animal model suitable for the study of male osteoporosis, for 8 weeks with OT and then analyzed trabecular and cortical bone parameters as well as fat mass using micro-computed tomography. Orchidectomized mice displayed severe bone loss, muscle atrophy accompanied by fat mass gain as expected in andropause. Interestingly, OT treatment in male mice normalized fat mass as it did in female mice. However, although OT treatment led to a normalization of bone parameters in ovariectomized mice, this did not happen in orchidectomized mice. Moreover, loss of muscle mass was not reversed in orchidectomized mice upon OT treatment. All of these observations indicate that OT acts on fat physiology in both sexes, but in a sex specific manner with regard to bone physiology.
Beranger GE, Djedaini M, Battaglia S, Roux CH…
Front Endocrinol (Lausanne) 2015
PMID: 26042090 | Free Full Text
Wnt modulators in the biotech pipeline.
Rey JP, Ellies DL
Dev. Dyn. Jan 2010
PMID: 20014100 | Free Full Text
A more favorable approach to the modulation of the Wnt pathway has been to focus on extracellular mediators of the pathway. Where, Amgen is the first in class to develop a biologic therapeutic against Sclerostin (Human Clinical Phase II). Nuvelo is following Amgen with biologics against LRP5, Dkk1, and R-Spondin (Discovery). Second in class for Sclerostin blocking antibodies will be Novartis and Eli Lilly (Preclinical). Fibrogen, who is taking a different approach, has developed a biologic against CCN family member CTGF (Preclinical). As for small molecules, OsteoGeneX is first in class to develop a Sclerostin small molecule inhibitor, currently in preclinical and lead optimization. Alternatively to Sclerostin, Galapagos is developing small molecule leads against LRP5 in a partnership with Eli-Lilly (Discovery).
A randomized, double-blind phase 2 clinical trial of blosozumab, a sclerostin antibody, in postmenopausal women with low bone mineral density.
Sclerostin, a SOST protein secreted by osteocytes, negatively regulates formation of mineralized bone matrix and bone mass. We report the results of a randomized, double-blind, placebo-controlled multicenter phase 2 clinical trial of blosozumab, a humanized monoclonal antibody targeted against sclerostin, in postmenopausal women with low bone mineral density (BMD). Postmenopausal women with a lumbar spine T-score -2.0 to -3.5, inclusive, were randomized to subcutaneous blosozumab 180 mg every 4 weeks (Q4W), 180 mg every 2 weeks (Q2W), 270 mg Q2W, or matching placebo for 1 year, with calcium and vitamin D. Serial measurements of spine and hip BMD and biochemical markers of bone turnover were performed. Overall, 120 women were enrolled in the study (mean age 65.8 years, mean lumbar spine T-score -2.8). Blosozumab treatment resulted in statistically significant dose-related increases in spine, femoral neck, and total hip BMD as compared with placebo. In the highest dose group, BMD increases from baseline reached 17.7% at the spine, and 6.2% at the total hip. Biochemical markers of bone formation increased rapidly during blosozumab treatment, and trended toward pretreatment levels by study end. However, bone specific alkaline phosphatase remained higher than placebo at study end in the highest-dose group. CTx, a biochemical marker of bone resorption, decreased early in blosozumab treatment to a concentration less than that of the placebo group by 2 weeks, and remained reduced throughout blosozumab treatment. Mild injection site reactions were reported more frequently with blosozumab than placebo. In conclusion, treatment of postmenopausal women with an antibody targeted against sclerostin resulted in substantial increases in spine and hip BMD. These results support further study of blosozumab as a potential anabolic therapy for osteoporosis.
Recker RR, Benson CT, Matsumoto T, Bolognese MA…
J. Bone Miner. Res. Feb 2015
PMID: 25196993 | Free Full Text
Low bone mineral density is associated with increased arterial stiffness in participants of a health records based study.
Many epidemiological studies have shown that low bone mineral density (BMD) and atherosclerosis appear to be related. However, their precise correlation is not completely understood after full adjustment the shared confounders of atherosclerosis and bone metabolism. The aim of this cross-sectional study was to investigate the relationship between BMD and subclinical atherosclerosis in a healthy Chinese population and the difference in gender.
The study population consisted of 2,487 subjects (1,467 men, 1,020 women) who participated in health check-up programs and were selected to be free of major diseases which might affect atherosclerosis and bone metabolism. Bone status was assessed by BMD in lumbar spine. The brachial-ankle PWV (baPWV) was assessed as a functional marker of atherosclerosis. The ankle-brachial index (ABI), carotid artery intima-media thickness (CIMT), estimated glomerular filtration rate (eGRF) and microalbuminuria were evaluated as indexes of structural markers of atherosclerosis.
After adjustment for risk factors, significant association was shown between baPWV and BMD in both genders (male: r=-0.084, P=0.035; female: r=-0.088, P=0.014). The correlation was stronger in females than in males, and in females, the correlation was stronger after menopause. Similarly, mean baPWV differed significantly according to the decreased BMD (normal BMD, Osteopenia, Osteoporosis). In contrast, no significant differences were observed for ABI, CIMT, eGFR or microalbuminuria with BMD.
Independent of confounding factors, low BMD is associated with the functional marker of subclinical atherosclerosis (increased baPWV), but not with structural markers (ABI, CIMT, eGFR or microalbuminuria) among healthy females and males.
Wang YQ, Yang PT, Yuan H, Cao X…
J Thorac Dis May 2015
PMID: 26101634 | Free Full Text
From the full text discussion:
There are several potential mechanisms to explain this link. Both osteoporosis and atherosclerosis share similar or common risk factors. Bone-associated matrix proteins, homocysteine, high levels of OPG, inflammatory mediators, estrogen and vitamin D deficiency all play an important role both in bone metabolism and in the development of atherosclerosis (32).
Milk, dietary calcium, and bone fractures in women: a 12-year prospective study.
This study examined whether higher intakes of milk and other calcium-rich foods during adult years can reduce the risk of osteoporotic fractures.
This was a 12-year prospective study among 77761 women, aged 34 through 59 years in 1980, who had never used calcium supplements. Dietary intake was assessed with a food-frequency questionnaire in 1980, 1984, and 1986. Fractures of the proximal femur (n = 133) and distal radius (n = 1046) from low or moderate trauma were self-reported on biennial questionnaires.
We found no evidence that higher intakes of milk or calcium from food sources reduce fracture incidence. Women who drank two or more glasses of milk per day had relative risks of 1.45 for hip fracture (95% confidence interval [CI] = 0.87, 2.43) and 1.05 for forearm fracture (95% CI = 0.88, 1.25) when compared with women consuming one glass or less per week. Likewise, higher intakes of total dietary calcium or calcium from dairy foods were not associated with decreased risk of hip or forearm fracture.
These data do not support the hypothesis that higher consumption of milk or other food sources of calcium by adult women protects against hip or forearm fractures.
Feskanich D, Willett WC, Stampfer MJ, Colditz GA
Am J Public Health Jun 1997
PMID: 9224182 | Free Full Text
Dietary calcium intake and mortality risk from cardiovascular disease and all causes: a meta-analysis of prospective cohort studies.
Considerable controversy exists regarding the association between dietary calcium intake and risk of mortality from cardiovascular disease and all causes. Therefore, we performed a meta-analysis of prospective cohort studies to examine the controversy.
We identified relevant studies by searching MEDLINE, Embase, and the Cochrane Library databases between 1 September 2013 and 30 December 2013. Reference lists of relevant articles were also reviewed. Observational prospective studies that reported relative risks and 95% confidence intervals for the association of calcium intake with cardiovascular and all-cause mortality were eligible. Study-specific relative risks were pooled using a random-effects model.
In this meta-analysis, 11 prospective studies with 12 independent cohorts, involving 757,304 participants, were eligible. There was evidence of a non-linear association between dietary calcium intake and risk of mortality from cardiovascular disease (P for non-linearity <0.01) and all causes (P for non-linearity <0.01). A dose-response analysis showed a U-shaped relationship between dietary calcium intake and cardiovascular mortality. Intakes that were lower and higher than around 800 mg/day were gradually associated with a higher risk of cardiovascular mortality. For all-cause mortality, we also observed a threshold effect at intakes around 900 mg/day. The risk of all-cause mortality did not decrease further at intakes above 900 mg/day.
This meta-analysis of prospective cohort studies suggests that dietary calcium intake is associated with cardiovascular mortality in a U-shaped manner and that high dietary calcium intake (>900 mg/day) is not associated with a decreased risk of all-cause mortality.
Wang X, Chen H, Ouyang Y, Liu J…
BMC Med 2014
PMID: 25252963 | Free Full Text
From the full text:
Calcium intake and fracture risk: results from the study of osteoporotic fractures.
The relation between dietary calcium, calcium, and vitamin D supplements and the risk of fractures of the hip (n = 332), ankle (n = 210), proximal humerus (n = 241), wrist (n = 467), and vertebrae (n = 389) was investigated in a cohort study involving 9,704 US white women aged 65 years or older. Baseline assessments took place in 1986-1988 in four US metropolitan areas. Dietary calcium intake was assessed at baseline with a validated food frequency questionnaire. Data on new nonvertebral fractures were collected every 4 months during a mean of 6.6 years of follow-up; identification of new vertebral fractures was based on comparison of baseline and follow-up radiographs of the spine done a mean of 3.7 years apart. Results were adjusted for numerous potential confounders, including weight, physical activity, estrogen use, protein intake, and history of falls, osteoporosis, and fractures. There were no important associations between dietary calcium intake and the risk of any of the fractures studied. Current use of calcium supplements was associated with increased risk of hip (relative risk = 1.5, 95% confidence interval 1.1-2.0) and vertebral (relative risk = 1.4, 95% confidence interval 1.1-1.9) fractures; current use of Tums antacid tablets was associated with increased risk of fractures of the proximal humerus (relative risk = 1.7, 95% confidence interval 1.3-2.4). There was no evidence of a protective effect of vitamin D supplements. Although a true adverse effect of calcium supplements on fracture risk cannot be ruled out, it is more likely that our findings are due to inadequately controlled confounding by indications for use of supplements. In conclusion, this study did not find a substantial beneficial effect of calcium on fracture risk.
Cumming RG, Cummings SR, Nevitt MC, Scott J…
Am. J. Epidemiol. May 1997
PMID: 9149664 | Free Full Text
Dietary calcium intake and risk of fracture and osteoporosis: prospective longitudinal cohort study.
To investigate associations between long term dietary intake of calcium and risk of fracture of any type, hip fractures, and osteoporosis.
A longitudinal and prospective cohort study, based on the Swedish Mammography Cohort, including a subcohort, the Swedish Mammography Cohort Clinical.
A population based cohort in Sweden established in 1987.
61,433 women (born between 1914 and 1948) were followed up for 19 years. 5022 of these women participated in the subcohort.
Primary outcome measures were incident fractures of any type and hip fractures, which were identified from registry data. Secondary outcome was osteoporosis diagnosed by dual energy x ray absorptiometry in the subcohort. Diet was assessed by repeated food frequency questionnaires.
During follow-up, 14,738 women (24%) experienced a first fracture of any type and among them 3871 (6%) a first hip fracture. Of the 5022 women in the subcohort, 1012 (20%) were measured as osteoporotic. The risk patterns with dietary calcium were non-linear. The crude rate of a first fracture of any type was 17.2/1000 person years at risk in the lowest quintile of calcium intake, and 14.0/1000 person years at risk in the third quintile, corresponding to a multivariable adjusted hazard ratio of 1.18 (95% confidence interval 1.12 to 1.25). The hazard ratio for a first hip fracture was 1.29 (1.17 to 1.43) and the odds ratio for osteoporosis was 1.47 (1.09 to 2.00). With a low vitamin D intake, the rate of fracture in the first calcium quintile was more pronounced. The highest quintile of calcium intake did not further reduce the risk of fractures of any type, or of osteoporosis, but was associated with a higher rate of hip fracture, hazard ratio 1.19 (1.06 to 1.32).
Gradual increases in dietary calcium intake above the first quintile in our female population were not associated with further reductions in fracture risk or osteoporosis.
Warensjö E, Byberg L, Melhus H, Gedeborg R…
PMID: 21610048 | Free Full Text
From the full text:
• Dietary calcium intakes below approximately 700 mg per day in women were associated with an increased risk of hip fracture, any fracture, and of osteoporosis
• The highest reported calcium intake did not further reduce the risk of fractures of any type, or of osteoporosis, but was associated with a higher rate of hip fracture
Effect of calcium supplementation on hip fractures.
There have been numerous studies of the effects of calcium supplementation, with or without vitamin D, on fractures. Individually, they have not provided clarity regarding calcium’s anti-fracture efficacy, though they have established that calcium does have beneficial effects on bone density throughout the skeleton in women. Meta-analysis of these data suggests that total fracture numbers are diminished. However, the data from the 5,500 women involved in trials of calcium monotherapy show consistent adverse trends in numbers of hip fractures (relative risk 1.50, 95% CI 1.06-2.12). Observational data from the Study of Osteoporotic Fractures show a similar increase in risk of hip fracture associated with calcium use. We hypothesize that reduced periosteal expansion in women using calcium supplementation might account for the differences in anti-fracture efficacy of calcium at the hip, in comparison with other sites. Until there are further trial results to clarify this area, the present findings suggest that reliance on high calcium intakes to reduce the risk of hip fracture in older women is not appropriate. In addition, those at risk should be looking to other agents with a proven capacity to prevent hip fractures, such as bisphosphonates.
Reid IR, Bolland MJ, Grey A
Osteoporos Int Aug 2008
PMID: 18286218 | Free Full Text
Furthermore, our own recent trial of calcium monotherapy suggested that there might be heterogeneity between the responses of hip and other fractures to calcium supplementation , with downward trends in vertebral, forearm, and total osteoporotic fractures, but a significant increase in hip fractures.
Observational studies have also assessed the relationship between calcium use and fractures. While there is a potential problem of confounding by indication, it is noteworthy that the Study of Osteoporotic Fractures reported an increase in hip fracture risk in postmenopausal women taking calcium supplements of almost identical magnitude to that found in the present meta-analysis (relative risk 1.5; 95%CI, 1.1–2.0) . This consistency across the available intervention studies and a large observational study raises doubts regarding the safety of calcium monotherapy in elderly postmenopausal women, though we cannot completely preclude the possibility that these results are a chance finding arising from the smaller numbers of this particular fracture type.
The adverse effect of calcium monotherapy on hip fractures poses the question of how this could occur when the same intervention has the opposite effect on total fracture numbers.