Repeated Measurement of the Novel Atrial Biomarker BMP10 (Bone Morphogenetic Protein 10) Refines Risk Stratification in Anticoagulated Patients With Atrial Fibrillation: Insights From the ARISTOTLE Trial

BACKGROUND

BMP10 (bone morphogenic protein 10) has emerged as a novel biomarker associated with the risk of ischemic stroke and other outcomes in patients with atrial fibrillation (AF). The study aimed to determine if repeated BMP10 measurements improve prognostication of cardiovascular events in patients with AF.

METHODS AND RESULTS

BMP10 was measured using a prototype Elecsys immunoassay in plasma samples collected at randomization and after 2 months in patients with AF randomized to apixaban or warfarin in the ARISTOTLE (Apixaban for Reduction in Stroke and Other Thromboembolic Events in Atrial Fibrillation) trial (n=2878). Adjusted Cox-regression models were used to evaluate the association between 2-month BMP10 levels and outcomes. BMP10 levels increased by 7.8% (P<0.001) over 2 months. The baseline variables most strongly associated with BMP10 levels at 2 months were baseline BMP10 levels, body mass index, sex, age, creatinine, diabetes, warfarin treatment, and AF-rhythm. During median 1.8 years follow-up, 34 ischemic strokes/systemic embolism, 155 deaths, and 99 heart failure hospitalizations occurred. Comparing the third with the first sample quartile, higher BMP10 levels at 2 months were associated with higher risk of ischemic stroke (hazard ratio [HR], 1.33 [95% CI, 0.67-2.63], P=0.037), heart failure (HR, 1.91 [95% CI, 1.17-3.12], P=0.012) and all-cause death (HR, 1.61 [95% CI, 1.17-2.21], P<0.001). Adding BMP10 levels at 2 months on top of established risk factors and baseline BMP10 levels improved the C-indices for ischemic stroke/systemic embolism (from 0.73 to 0.75), heart failure hospitalization (0.76-0.77), and all-cause mortality (0.70-0.72), all P<0.05.

CONCLUSIONS

Elevated levels of BMP10 at 2 months strengthened the associations with the risk of ischemic stroke, hospitalization for heart failure, and all-cause mortality. Repeated measurements of BMP10 may further refine risk stratification in patients with AF.

[Correlation between serum growth differentiation factor 11 level and severity of coronary artery disease in patients with acute myocardial infarction]

Objective: To investigate the correlation between serum growth differentiation factor 11 (GDF11) level and coronary artery lesions in patients with ST-segment elevation myocardial infarction (STEMI), and the predictive efficacy of nomogram risk prediction model based on GDF11 combined with traditional risk factors on the occurrence of STEMI. Methods: This study was a retrospective cross-sectional study. Patients hospitalized in the Department of Cardiology of the 904th Hospital of Joint Logistic Support Force of People's Liberation Army of China from 2016 to 2018 were selected and divided into control group and STEMI group. The demographic data, blood lipid level, laboratory indicators of blood and GDF11 level were collected. Logistic regression analysis screened out independent correlated factors for the occurrence of STEMI. Spearman correlation analysis clarified the correlation of each indicator with the SYNTAX or Gensini scores. A nomogram risk prediction model for the risk of STEMI occurrence and the receiver operating characteristic curve was used to compare the prediction efficiency of each model. Results: A total of 367 patients were enrolled, divided into control group (n=172) and STEMI group (n=195), age (66.5±11.8), male 222 (60.49%). The serum GDF11 level of STEMI group was significantly lower than that of the control group (36.20 (16.60, 70.75) μg/L vs. 85.00 (53.93, 117.10) μg/L, P<0.001). The results of multivariate logistic regression analysis showed serum GDF11(OR=0.98, 95%CI: 0.97-0.99) and traditional independent risk factors such as smoking, diabetes, C-reactive protein, homocysteine, lipoprotein (a) and apolipoprotein A1/B were independent correlate factors for the occurrence of STEMI (P<0.05). Spearman correlation analysis showed that serum GDF11 was negatively correlated with SYNTAX score and Gensini score (P<0.05). The nomogram model constructed by serum GDF11 combined with traditional independent risk factors (AUC=0.85, 95%CI: 0.81-0.89) had better predictive value for the occurrence of STEMI than the traditional nomogram model constructed by independent risk factors(AUC=0.80, 95%CI:0.75-0.84) or serum GDF11 (AUC=0.76, 95%CI: 0.72-0.81), all P<0.01. Conclusions: Serum GDF11 is an independent correlate factor in the occurrence of STEMI and is negatively correlated with the severity of coronary artery lesions in patients with STEMI. The nomogram model constructed based on GDF11 combined with traditional risk factors can be a good predictor for the occurrence of STEMI.

Circulating Growth Differentiation Factors 11 and 8, Their Antagonists Follistatin and Follistatin-Like-3, and Risk of Heart Failure in Elders

BACKGROUND

Heterochronic parabiosis has identified growth differentiation factor (GDF)-11 as a potential means of cardiac rejuvenation, but findings have been inconsistent. A major barrier has been lack of assay specificity for GDF-11 and its homolog GDF-8.

METHODS

We tested the hypothesis that GDF-11 and GDF-8, and their major antagonists follistatin and follistatin-like (FSTL)-3, are associated with incident heart failure (HF) and its subtypes in elders. Based on validation experiments, we used liquid chromatography-tandem mass spectrometry to measure total serum GDF-11 and GDF-8, along with follistatin and FSTL-3 by immunoassay, in 2 longitudinal cohorts of older adults.

RESULTS

In 2 599 participants (age 75.2 ± 4.3) followed for 10.8 ± 5.6 years, 721 HF events occurred. After adjustment, neither GDF-11 (HR per doubling: 0.93 [0.67, 1.30]) nor GDF-8 (HR: 1.02 per doubling [0.83, 1.27]) was associated with incident HF or its subtypes. Positive associations with HF were detected for follistatin (HR: 1.15 [1.00, 1.32]) and FLST-3 (HR: 1.38 [1.03, 1.85]), and with HF with preserved ejection fraction for FSTL-3 (HR: 1.77 [1.03, 3.02]). (All HRs per doubling of biomarker.) FSTL-3 associations with HF appeared stronger at higher follistatin levels and vice versa, and also for men, Blacks, and lower kidney function.

CONCLUSIONS

Among older adults, serum follistatin and FSTL-3, but not GDF-11 or GDF-8, were associated with incident HF. These findings do not support the concept that low serum levels of total GDF-11 or GDF-8 contribute to HF late in life, but do implicate transforming growth factor-β superfamily pathways as potential therapeutic targets.

Reduced leukocyte telomere lengths and sirtuin 1 gene expression in long-term survivors of type 1 diabetes: A Dialong substudy

AIMS/INTRODUCTION

The shortening of leukocyte telomere length with age has been associated with coronary disease, whereas the association with type 1 diabetes is unclear. We aimed to explore telomere lengths in diabetes patients with regard to coronary artery disease, compared with healthy controls. The longevity factors sirtuin 1 and growth-differentiating factor 11 were investigated accordingly.

MATERIALS AND METHODS

We carried out a cross-sectional study of 102 participants with long-term type 1 diabetes and 75 controls (mean age 62 and 63 years, respectively), where 88 cases and 60 controls without diagnosed coronary artery disease completed computed tomography coronary angiography. Telomere lengths and gene expression of sirtuin 1 and growth-differentiating factor 11 were quantified in leukocytes.

RESULTS

Telomere lengths and sirtuin 1 were reduced in diabetes patients versus controls, medians (25th to 75th percentiles): 0.97 (0.82-1.15) versus 1.08 (0.85-1.29) and 0.88 (0.65-1.14) vs 1.01 (0.78-1.36), respectively, adjusted P < 0.05, both. Previous coronary artery disease in diabetes patients (n = 15) was associated with lower sirtuin 1 and growth-differentiating factor 11 messenger ribonucleic acid expression (adjusted P < 0.03, both). In the combined diabetes and control group, previous artery coronary disease (n = 18) presented with significantly shorter telomeres (adjusted P = 0.038). Newly diagnosed obstructive coronary artery disease, defined as >50% stenosis, was not associated with the investigated variables.

CONCLUSIONS

Long-term type 1 diabetes presented with reduced telomeres and sirtuin 1 expression, with additional reduction in diabetes patients with previous coronary artery disease, showing their importance for cardiovascular disease development with potential as novel biomarkers in diabetes and coronary artery disease.

Serum growth differentiation factor 11 is closely related to metabolic syndrome in a Chinese cohort

AIMS/INTRODUCTION

Despite increasing interest in growth differentiation factor 11 (GDF11) based on its involvement in age-related disorders, clinical implications - especially for metabolic diseases - remain unclear. Therefore, we assessed the association between serum GDF11 levels and metabolic disturbance in the Chinese population.

MATERIALS AND METHODS

A total of 381 individuals from the Shanghai Nicheng Cohort Study were included. In addition to anthropometry, laboratory and ultrasonography measurements, serum concentrations of GDF11 were measured by enzyme-linked immunosorbent assay.

RESULTS

Circulating GDF11 concentrations were unchanged with age (r = -0.064, P = 0.210), but showed an inverse relationship to body mass index, waist circumference and fat-free mass index (all P < 0.05). Correlation analysis showed decreased GDF11 concentrations accompanied by elevated diastolic blood pressure, fasting and 2-h plasma glucose, triglycerides, and low-density lipoprotein cholesterol after adjusting for sex, age and body mass index, whereas variations in aspartate aminotransferase and free thyroxine were consistent with GDF11 (all P < 0.05). Furthermore, people, especially men, with abnormal glycometabolism, body mass index and/or fat accumulation in the liver had lower serum levels of GDF11 (P < 0.05); an increase in metabolic syndrome morbidity along with the circulatory decline of GDF11 was found when stratified by GDF11-level quartiles (P-trend <0.001). Logistic regression showed that serum GDF11 levels were independently correlated with the presence of metabolic syndrome (odds ratio 0.665, 95% confidence interval 0.510-0.867, P = 0.003).

CONCLUSIONS

We confirmed GDF11 as an endocrine factor playing a significant role in multiple metabolic processes and an indicator of metabolic syndrome in the Chinese population, particularly in males.

Plasma levels of apelin are reduced in patients with liver fibrosis and cirrhosis but are not correlated with circulating levels of bone morphogenetic protein 9 and 10

BACKGROUND

The peptide apelin is expressed in human healthy livers and is implicated in the development of hepatic fibrosis and cirrhosis. Mutations in the bone morphogenetic protein receptor type II (BMPR-II) result in reduced plasma levels of apelin in patients with heritable pulmonary arterial hypertension. Ligands for BMPR-II include bone morphogenetic protein 9 (BMP9), highly expressed in liver, and BMP10, expressed in heart and to a lesser extent liver. However, it is not known whether reductions in BMP9 and/or BMP10, with associated reduction in BMPR-II signalling, correlate with altered levels of apelin in patients with liver fibrosis and cirrhosis.

METHODS

Plasma from patients with liver fibrosis (n = 14), cirrhosis (n = 56), and healthy controls (n = 25) was solid-phase extracted using a method optimised for recovery of apelin, which was measured by ELISA.

RESULTS

Plasma apelin was significantly reduced in liver fibrosis (8.3 ± 1.2 pg/ml) and cirrhosis (6.5 ± 0.6 pg/ml) patients compared with controls (15.4 ± 2.0 pg/ml). There was no obvious relationship between apelin and BMP 9 or BMP10 previously measured in these patients. Within the cirrhotic group, there was no significant correlation between apelin levels and disease severity scores, age, sex, or treatment with β-blockers.

CONCLUSIONS

Apelin was significantly reduced in plasma of patients with both early (fibrosis) and late-stage (cirrhosis) liver disease. Fibrosis is more easily reversible and may represent a potential target for new therapeutic interventions. However, it remains unclear whether apelin signalling is detrimental in liver disease or is beneficial and therefore, whether an apelin antagonist or agonist have clinical use.

Bone losses in obese, ovariectomized rats appear to be independent from sclerostin-induced inhibition of the Wnt/β-catenin pathway

INTRODUCTION

Overweight and obesity, as well as a gonadal function, are pivotal factors influencing bone tissue metabolism.

MATERIAL AND METHODS

The aim of the study was to determine the effect of dietary induced obesity (DIO) on bone tissue metabolism in sham-operated (SHO) or ovariectomized (OVX) adult female Wistar rats. Additionally, the influence of DIO in SHO or OVX on the concentration of sclerostin in the blood serum was analyzed. After SHO or OVX, the rats were placed in groups (n=8) and either received a standard diet (11.5 MJ/kg) (SHO-CON; OVX-CON) or a high-energy diet (17.6 MJ/kg) (SHO-FAT; OVX-FAT). The experiment lasted for 90 days and allowed for the establishment of osteopenia in OVX females and obesity in the rats that had received the high-energy diet.

RESULTS

The results of the study demonstrate that obesity or/and ovariectomy increases the resorption of femora and tibiae, hence decreasing the densitometric and mechanical parameters affecting the bone structure in adult females rats. The strongest osteodegenerative effect was seen in the OVX-FAT females. Interestingly, the degree of bone tissue degradation caused exclusively by ovariectomy was similar to that found in the obese sham-operated rats.

CONCLUSIONS

Bone losses invoked by DIO seem to be independent from the Wnt/β-catenin pathway inhibition induced by sclerostin. While further study is necessary, the obtained results suggest that the usage of sclerostin anti-body in the treatment of osteoporosis can be ineffective, and in obese patients the undertaking of such therapy should be reassessed.

Reduced left atrial cardiomyocyte PITX2 and elevated circulating BMP10 predict atrial fibrillation after ablation

BACKGROUNDGenomic and experimental studies suggest a role for PITX2 in atrial fibrillation (AF). To assess if this association is relevant for recurrent AF in patients, we tested whether left atrial PITX2 affects recurrent AF after AF ablation.METHODSmRNA concentrations of PITX2 and its cardiac isoform, PITX2c, were quantified in left atrial appendages (LAAs) from patients undergoing thoracoscopic AF ablation, either in whole LAA tissue (n = 83) or in LAA cardiomyocytes (n = 52), and combined with clinical parameters to predict AF recurrence. Literature suggests that BMP10 is a PITX2-repressed, atrial-specific, secreted protein. BMP10 plasma concentrations were combined with 11 cardiovascular biomarkers and clinical parameters to predict recurrent AF after catheter ablation in 359 patients.RESULTSReduced concentrations of cardiomyocyte PITX2, but not whole LAA tissue PITX2, were associated with AF recurrence after thoracoscopic AF ablation (16% decreased recurrence per 2-(ΔΔCt) increase in PITX2). RNA sequencing, quantitative PCR, and Western blotting confirmed that BMP10 is one of the most PITX2-repressed atrial genes. Left atrial size (HR per mm increase [95% CI], 1.055 [1.028, 1.082]); nonparoxysmal AF (HR 1.672 [1.206, 2.318]), and elevated BMP10 (HR 1.339 [CI 1.159, 1.546] per quartile increase) were predictive of recurrent AF. BMP10 outperformed 11 other cardiovascular biomarkers in predicting recurrent AF.CONCLUSIONSReduced left atrial cardiomyocyte PITX2 and elevated plasma concentrations of the PITX2-repressed, secreted atrial protein BMP10 identify patients at risk of recurrent AF after ablation.TRIAL REGISTRATIONClinicalTrials.gov NCT01091389, NL50069.018.14, Dutch National Registry of Clinical Research Projects EK494-16.FUNDINGBritish Heart Foundation, European Union (H2020), Leducq Foundation.

Clinical significance of fluid biomarkers in Alzheimer's Disease

The number of patients with Alzheimer's Disease (AD) and other types of dementia disorders has drastically increased over the last decades. AD is a complex progressive neurodegenerative disease affecting about 14 million patients in Europe and the United States. The hallmarks of this disease are neurotic plaques consist of the Amyloid-β peptide (Aβ) and neurofibrillary tangles (NFTs) formed of hyperphosphorylated Tau protein (pTau). Currently, four CSF biomarkers: Amyloid beta 42 (Aβ42), Aβ42/40 ratio, Tau protein, and Tau phosphorylated at threonine 181 (pTau181) have been indicated as core neurochemical AD biomarkers. However, the identification of additional fluid biomarkers, useful in the prognosis, risk stratification, and monitoring of drug response is sorely needed to better understand the complex heterogeneity of AD pathology as well as to improve diagnosis of patients with the disease. Several novel biomarkers have been extensively investigated, and their utility must be proved and eventually integrated into guidelines for use in clinical practice. This paper presents the research and development of CSF and blood biomarkers for AD as well as their potential clinical significance. Upper panel: Aβ peptides are released from transmembrane Amyloid Precursor Protein (APP) under physiological conditions (blue arrow). In AD, however, pathologic accumulation of Aβ monomers leads to their accumulation in plaques (red arrow). This is reflected in decreased concentration of Aβ1-42 and decreased Aβ42/40 concentration ratio in the CSF. Lower panel: Phosphorylated Tau molecules maintain axonal structures; hyperphosphorylation of Tau (red arrow) in AD leads to degeneration of axons, and release of pTau molecules, which then accumulate in neurofibrillary tangles. This process is reflected by increased concentrations of Tau and pTau in the CSF.

Serum Sclerostin and Bone Morphogenetic Protein-2 Levels in Patients with Ankylosing Spondylitis: A Meta-Analysis

Various studies have investigated the serum sclerostin and bone morphogenetic protein-2 (BMP-2) levels in patients with ankylosing spondylitis (AS), but the results were inconsistent. The aim of this meta-analysis was to synthetically assess the associations of serum levels of sclerostin and BMP-2 with AS. Multiple electronic databases were searched to locate relevant articles published before November 2018. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated by the random-effect model. Totally, 21 studies were included. Meta-analysis results showed no significant difference between AS group and control group in serum sclerostin levels (SMD = 0.098, 95% CI - 0.395 to 0.591, p = 0.697). Nevertheless, serum BMP-2 levels in AS patients were higher than that in controls (SMD = 1.184, 95% CI 0.209 to 2.159, p = 0.017). Subgroup analysis demonstrated that European and South American AS patients had lower serum levels of sclerostin than controls. AS patients with age ≥ 40 years, erythrocyte sedimentation rate (ESR) ≤ 20 mm/h and Bath Ankylosing Spondylitis Functional Index (BASFI) < 4 had statistically significant lower serum sclerostin concentrations compared to controls. Chinese and Korean AS patients as well as patients with lower CRP had higher serum BMP-2 levels than controls, and country may be a source of heterogeneity across the studies. No publication bias existed and sensitivity analysis confirmed the stability of results. Serum BMP-2, but not sclerostin levels may be closely related to the development of AS.

Once-weekly teriparatide reduces serum sclerostin levels in postmenopausal women with osteoprosis

Once-weekly teriparatide treatment is widely used in the treatment of osteoporosis in Japan but the mechanisms causing the increase in bone mineral density (BMD) of the lumbar spine remain unknown.

METHODS

This prospective study examined the effects of once-weekly teriparatide treatment on the serum levels of sclerostin, osteocalcin, and bone formation markers as well as BMD of the lumbar spine and femoral neck in 32 postmenopausal women with osteoporosis.

RESULTS

The mean age of subjects was 76.3 ± 7.0 years old. Teriparatide significantly reduced serum sclerostin levels at 12 and 18 months in postmenopausal women with osteoporosis, and significantly increased serum osteocalcin levels at 3,12 and 18 months and PINP levels at 1 and 3 months, respectively. Teriparatide treatment significantly increased BMD of the lumbar spine at 6, 12, and 18 months, but did not affect BMD of the femoral neck. Examination of the relationships between percent changes in bone metabolic indices and BMD of the lumbar spine during the teriparatide treatment showed serum sclerostin changes at 3 months were negatively correlated with BMD changes of the lumbar spine at 6, 12, and 18 months. Serum osteocalcin changes were not correlated with BMD changes in the lumbar spine at 12 months.

CONCLUSIONS

The present study showed that once-weekly teriparatide treatment reduced serum sclerostin levels in postmenopausal women with osteoporosis. The effects of teriparatide on sclerostin may be associated with the response of the BMD of the lumbar spine.

Correlation between sclerostin and Dickkopf-1 with aortic arterial stiffness in patients with type 2 diabetes: A prospective, cross-sectional study

BACKGROUND

Sclerostin and Dickkopf-1 are extracellular inhibitors of the canonical Wnt/β-catenin signalling pathway, which is implicated in the development of arterial stiffness. However, the correlation between aortic stiffness and sclerostin or Dickkopf-1 levels in patients with type 2 diabetes mellitus is unknown.

METHODS

Fasting blood samples were collected from 125 patients with type 2 diabetes mellitus. Aortic stiffness was measured by carotid-femoral pulse wave velocity, and high aortic stiffness was defined by a carotid-femoral pulse wave velocity of >10 m/s. The serum sclerostin and Dickkopf-1 concentrations were determined using commercially available enzyme-linked immunosorbent assays.

RESULTS

In total, 46 patients with type 2 diabetes mellitus (36.8%) had high levels of aortic stiffness. Compared to the control group without aortic stiffness, this group was significantly older, had higher systolic and diastolic blood pressures, had higher blood urea nitrogen, creatinine, urinary albumin-to-creatinine ratio and serum sclerostin levels, and had significantly lower high-density lipoprotein cholesterol levels and estimated glomerular filtration rates. After adjusting for confounders, serum sclerostin [odds ratio = 1.005 (1.002-1.007), p = 0.002] levels remained an independent predictor of aortic stiffness. Multivariate analysis showed that the serum sclerostin level ( β = 0.374, adjusted R² change = 0.221, p < 0.001) was positively associated with carotid-femoral pulse wave velocity.

CONCLUSION

Serum levels of sclerostin, but not Dickkopf-1, are positively correlated with carotid-femoral pulse wave velocity and independently predict aortic stiffness in patients with type 2 diabetes mellitus.

Exercise Alleviates Osteoporosis in Rats with Mild Chronic Kidney Disease by Decreasing Sclerostin Production

Chronic kidney disease–mineral bone disorder (CKD–MBD), comprising mineral, hormonal, and bone metabolic imbalance, is a major CKD-related issue; it causes osteoporosis prevalence in CKD patients. Osteocyte-derived sclerostin inhibits the osteogenic Wnt/β-catenin signaling pathway; its levels rise when kidney function declines. Exercise modulates the physiological functions of osteocytes, potentially altering sclerostin production. It may aid bone and mineral electrolyte homeostasis in CKD. Mild CKD was induced in rats by partial nephrectomy. They were divided into: sham (no CKD), CKD, and CKD + exercise (8 weeks of treadmill running) groups. Micro-CT scanning demonstrated that the CKD + exercise-group rats had a higher bone mineral density (BMD) of the spine and femoral metaphysis and higher femoral trabecular bone volume than the CKD-group rats. Bone formation rates were not significantly different. The CKD + exercise-group rats had lower serum sclerostin (157.1 ± 21.1 vs 309 ± 38.1 pg/mL, p < 0.05) and CTX-1 (bone resorption marker) levels. Immunohistochemistry revealed higher tibial β-catenin concentrations in the CKD + exercise-group rats. Serum FGF-23, intact parathyroid hormone (iPTH), alkaline phosphatase (ALP), calcium, and phosphate levels showed no significant differences between these groups. Thus, exercise improves BMD and bone microstructure in mild CKD by inhibiting sclerostin production, but does not alter serum minerals.

Relationship between plasma levels of sclerostin, calcium-phosphate disturbances, established markers of bone turnover, and inflammation in haemodialysis patients

PURPOSE

Data concerning the relation between increased levels of circulating sclerostin (a physiological inhibitor of bone formation) and bone turnover in patients with chronic renal failure (CRF) are limited. Therefore, the aim of this study was to evaluate associations between plasma sclerostin levels and calcium-phosphate disturbances, markers of bone turnover as well as inflammation in haemodialysis (HD) patients.

METHODS

In plasma samples obtained in 150 stable HD patients (92 men) aged 40-70 years, levels of sclerostin, fibroblast growth factor (cFGF23), osteocalcin, the N-terminal propeptide of type I procollagen, C-terminal telopeptide of the alpha chain of type I collagen (β-CTx), and inflammatory markers (IL-6 and TNF-α) in addition to routine parameters (calcium, phosphorus, parathyroid hormone-iPTH, 25-OH-D, alkaline phosphatase) were measured.

RESULTS

Plasma sclerostin concentrations were significantly higher in HD men than women (2.61 vs. 1.88 ng/mL, p < 0.01). Patients with sclerostin levels above median were characterized by lower iPTH and IL-6, but higher cFGF23 and TNF-α (significantly only in men) concentrations. Plasma sclerostin concentration positively correlated with serum 25-OH-D (τ = 0.204), phosphorus (τ = 0.1482), and TNF-α (τ = 0.183) and inversely with iPTH (τ = - 0.255), alkaline phosphatase (τ = - 0.203), IL-6 (τ =- 0.201), and β-CTx (τ = - 0.099) levels. In multivariate regression analysis, variability of sclerostin levels was explained by sex and 25-OH-D and phosphorus levels.

CONCLUSIONS

Increased circulating sclerostin levels seem to reflect slower bone turnover in HD patients. Low levels of sclerostin are associated with vitamin D deficiency and good phosphates alignment.

Relationship between serum level of growth differentiation factors 8, 11 and bone mineral density in girls with anorexia nervosa

BACKGROUND

Adolescents with anorexia nervosa (AN) have low body mass and low bone mineral density (BMD). Growth differentiation factor 8 (Myostatin, GDF8) and its homologue growth differentiation factor 11 (GDF11), members of the TGF-β super-family, play an important role in muscle regeneration and bone metabolism in healthy individuals. However, their association with BMD in AN is unknown. The present study was undertaken to investigate the relationship between GDF8, GDF11 and BMD in adolescent girls with AN.

METHODS

Serum GDF8, GDF11 and BMD were determined in 25 girls (12-16 years old) with AN and 31 healthy girls (12-16 years old).

RESULTS

Growth differentiation factor 8 levels were lower in AN subjects. On the contrary, GDF11 levels were higher in AN subjects than controls. There was no relationship between GDF8 and BMD. A significant negative correlation between GDF11 and BMD was found. In multiple linear stepwise regression analysis, BMI, 25-hydroxyvitamin D, GDF11, or lean mass, but not fat mass and GDF8, were independent predictors of BMD in the AN and control groups separately.

CONCLUSIONS

Growth differentiation factor 11 was independent predictor of BMD in girls with AN. It suggested that GDF11 exerts a negative effect on bone mass.

[Wnt signaling and bone metabolic diseases.]

Wnt signaling is known to be involved in metabolic bone disorders. Serum levels of sclerostin, a bone-specific protein that inhibits Wnt signaling, have been investigated in a variety of metabolic bone disorders. Serum sclerostin levels are positively correlated with bone mineral density in patients with osteoporosis. Elderly women with high serum sclerostin levels, however, are at increased risk of bone fractures. Since serum sclerostin levels are low in primary hyperparathyroidism and high in hypoparathyroidism, parathyroid hormone could be classified as a factor that regulates sclerostin levels. Serum sclerostin levels are high in glucocorticoid-induced osteoporosis and diabetes mellitus, which feature reduced bone formation. Finally, serum sclerostin levels increase with decreasing renal function. These findings highlight the potential of serum sclerostin levels as a new index for bone assessments which are different in nature from bone mineral density and bone metabolic markers.

Alterations in bone turnover markers in patients with noncardio-embolic ischemic stroke

Background

The major cause of ischemic stroke is unstable or thrombogenic atherosclerotic plaques. Vascular calcification, a process that appears crucial for plaque stability, shares common features with bone formation. Many bone turnover proteins exhibit metabolic properties, but the evidence is conflicting regarding their possible involvement in vascular disease. Antibodies against sclerostin and dickkopf-1 are currently being evaluated as potential therapy for treating bone disorders. It is important to carefully assess the cardiovascular and metabolic effects of these proteins. The aim of the present study was to explore serum levels of bone turnover markers in patients with acute noncardio-embolic ischemic stroke in comparison with healthy controls.

Methods

In a cross-sectional study, we compared 48 patients aged ≥75 years with noncardio-embolic ischemic stroke and 46 healthy controls. Serum levels of dickkopf-1, sclerostin, osteoprotegerin, osteopontin and osteocalcin were determined by Luminex technique.

Results

We found clearly increased serum levels of osteoprotegerin, sclerostin, dickkopf-1 and osteopontin in patients with stroke compared with healthy controls. No difference was seen in serum levels of osteocalcin between the two groups.

Conclusion

Our findings strengthen the hypothesis of bone turnover markers being involved in vascular disease. Whether these proteins can be used as candidate markers for increased stroke risk or prognostic biomarkers remains to be further elucidated.

Serum levels of sclerostin as a potential biomarker in central arterial stiffness among hypertensive patients

BACKGROUND

Sclerostin is known to be a canonical Wnt/β-catenin signaling pathway inhibitor, while the Wnt/β-catenin signaling pathway is proposed to be involved in the development of arterial stiffness. This study aims to investigate the relationship between serum sclerostin levels and carotid-femoral pulse wave velocity (cfPWV) among hypertensive patients.

METHODS

Fasting blood samples were obtained from 105 hypertensive patients. Patients with cfPWV values of > 10 m/s were classified in the high arterial stiffness group, whereas those with cfPWV values of ≤10 m/s were assigned to the low arterial stiffness group. Serum sclerostin and Dickkopf-1 (DKK1) levels were quantified using commercially available enzyme-linked immunosorbent assays.

RESULTS

Thirty-six hypertensive patients (34.3%) who belonged to the high arterial stiffness group were generally older (p < 0.001), presented with lower estimated glomerular filtration rates (eGFR, p = 0.014), higher incidence of diabetes mellitus (p = 0.030), average systolic blood pressures (SBP, p = 0.013), pulse pressure (p = 0.026), serum creatinine levels (p = 0.013), intact parathyroid hormone levels (iPTH, p = 0.003), and sclerostin levels (p < 0.001) than their counterparts in the low arterial stiffness group. A multivariable logistic regression analysis identified sclerostin as an independent predictor of arterial stiffness in hypertensive patients (odds ratio, 1.042; 95% confidence interval (CI), 1.017-1.068; p = 0.001). Multivariable forward stepwise linear regression analysis also showed that serum sclerostin level (β = 0.255, adjusted R2 change: 0.146, p = 0.003) was positively associated with cfPWV values in patients with hypertension.

CONCLUSIONS

In this study, serum sclerostin level, but not DKK1, is found to be positively correlated with cfPWV values and is identified as an independent predictor of arterial stiffness in hypertensive patients after adjusting for significant confounders.

Serum sclerostin and irisin as predictive markers for atherosclerosis in Egyptian type II diabetic female patients: A case control study

Diabetes mellitus represents a major independent risk factor for developing fatal cardiovascular diseases (CVDs) presumably through accelerating atherosclerosis; the underlying cause of most CVDs. Notably, this relative risk is reported to be higher in women than men. Endeavors directed towards identifying novel reliable predictive biomarkers are immensely thereby urged to improve the long-term outcome in these diabetic female patients. Sclerostin (SOST) is a Wnt signaling antagonist whereas irisin is a muscle-derived factor released after exercising which enhances browning of white adipose tissue. Emerging lines of evidence hint at potential crosstalk between them and CVDs. The present study aimed to assess the serum levels of SOST and irisin in Egyptian type 2 diabetic (T2DM) female patients with and without atherosclerosis and explore the possible relationship between both markers and other studied parameters among the studied cohorts. In this case-control study, 69 female subjects were enrolled; 39 type 2 diabetes patients with atherosclerosis (T2DM+ATHR), 22 type 2 diabetes patients without atherosclerosis (T2DM-ATHR) and 8 healthy controls. Their serum levels of SOST and irisin were assessed using ELISA. Significant increase in SOST levels were found in T2DM+ATHR compared to T2DM-ATHR and control (259.9 ±17.98 vs. 165.8±13.12 and 142.0±13.31 pg/mL respectively, P<0.001). Conversely, irisin levels were significantly lower in T2DM+ATHR (P<0.001) and T2DM-ATHR (P<0.01) compared to the control group (32.91±2.545 and 58.55±13.19 vs. 473.6±112.7 pg/mL). Interestingly, significant correlations between the levels of SOST and both irisin and fasting blood glucose were noticed in T2DM+ATHR group (r = 0.3754 and 0.3381 respectively, P<0.05). In conclusion, to the best of our knowledge, this study is the first to demonstrate the correlation between SOST and irisin levels in atherosclerotic T2DM female patients implying their potential implication in diabetic cardiovascular pathophysiology and supporting their use as reliable diagnostic/prognostic biomarkers for monitoring and preventing CVDs progression of T2DM female patients.

Pulsed electromagnetic fields modulate bone metabolism via RANKL/OPG and Wnt/β-catenin pathways in women with postmenopausal osteoporosis: A pilot study

Pulsed electromagnetic fields (PEMFs) have been proven to enhance in vitro and in vivo osteogenesis with unknown mechanism. Aim of our study was to explore whether RANKL/OPG and Wnt/β-Catenin pathways could be involved in bone response to PEMFs in a setting of postmenopausal osteoporotic women. Forty-three women (mean age 62.8 ± 4.5 yr.) were randomized into two groups. The PEMFs group received PEMFs treatment (50 min treatment session/day, 6 treatment sessions/week, for a total of 25 times), by wearing a specific gilet applied to the trunk and connected to the electromagnetic device (Biosalus, by HSD Srl, Serravalle RSM), while women assigned to control group received sham PEMFs with the same device. BSAP as bone formation and CTX as bone resorption markers, RANKL, OPG, β-Catenin, DKK-1 and sclerostin were obtained at baseline, after 30 and 60 days. In PEMFs group, BSAP levels significantly increased after 30 and 60 days while CTX concentrations decreased at day 60. RANKL levels significantly decreased after 60 days. OPG was not significantly changed, but the RANKL/OPG ratio significantly decreased at day 30. DKK-1 levels decreased, while β-catenin concentrations increased after 30 and 60 days (P < 0.05). No significant changes of calcium, phosphorus, creatinine and sclerostin were detected. In the PEMFs group, at day 30, Δsclerostin was associated with ΔRANKL/OPG ratio (r = -0.5, P = 0.03) and ΔDKK-1 was associated with Δβ-Catenin (r = -0.47, P = 0.02). In women with postmenopausal osteoporosis, our data provide evidence of a PEMFs modulation of RANKL/OPG and Wnt/β-Catenin signaling pathways able to explain the metabolic effects of PEMFs on bone.

Genetic variation in Wnt/β-catenin and ER signalling pathways in female and male elite dancers and its associations with low bone mineral density: a cross-section and longitudinal study

The association of genetic polymorphisms with low bone mineral density in elite athletes have not been considered previously. The present study found that bone mass phenotypes in elite and pre-elite dancers are related to genetic variants at the Wnt/β-catenin and ER pathways.

INTRODUCTION

Some athletes (e.g. gymnasts, dancers, swimmers) are at increased risk for low bone mineral density (BMD) which, if untreated, can lead to osteoporosis. To investigate the association of genetic polymorphisms in the oestrogen receptor (ER) and the Wnt/β-catenin signalling pathways with low BMD in elite and pre-elite dancers (impact sport athletes).

METHODS

The study included three phases: (1) 151 elite and pre-elite dancers were screened for the presence of low BMD and traditional osteoporosis risk factors (low body weight, menstrual disturbances, low energy availability); (2) a genetic association study was conducted in 151 elite and pre-elite dancers and age- and sex- controls; (3) serum sclerostin was measured in 101 pre-elite dancers and age- and sex-matched controls within a 3-year period.

RESULTS

Eighty dancers revealed low BMD: 56.3% had at least one traditional osteoporosis risk factor, whereas 28.6% did not display any risk factor (37.2% revealed traditional osteoporosis risk factors, but had normal BMD). Body weight, menstrual disturbances and energy availability did not fully predict bone mass acquisition. Instead, genetic polymorphisms in the ER and Wnt/β-catenin pathways were found to be risk factors for low BMD in elite dancers. Sclerostin was significantly increased in dancers compared to controls during the 3-year follow-up (p < 0.05).

CONCLUSIONS

Elite and pre-elite dancers demonstrate high prevalence of low BMD, which is likely related to genetic variants at the Wnt/β-catenin and ER pathways and not to factors usually associated with BMD in athletes (body weight, menstrual disturbances, energy deficiency).

Activin subfamily peptides predict chronological age in humans

Loss of muscle mass and function are a well-defined aspect of human aging from the 3rd decade of life, which result in reduced independence and increased mortality. The activin family of peptides contains several endocrine factors (activin A, myostatin, growth and differentiation factor 11 [GDF11]) that may play roles in changes in muscle mass and the aging process, however, it may be simplistic to consider aging as a result of a single peptides changes. Thus, we aimed to examine changes in activin family members across a cohort of healthy individuals of various ages, hypothesizing that these would aid predictive models of age and functional measures of age. Healthy participants (n = 88) were recruited and resting metabolic rate, body composition, grip strength, walking speed, and circulating plasma concentrations of myostatin (total and free), activin A, follistatin-like binding protein (FLRG), and GDF11 quantified. Simple regressions between circulating factors and chronological age, grip strength, and walking speed were examined. Multiple stepwise regressions for age, grip strength, and walking speed are also reported. Age negatively correlated with total myostatin (P = 0.032, r2  = 0.053), grip strength positively with activin A (P = 0.046, r2  = 0.048), whereas walking speed showed no simple regression relationships. Stepwise regressions suggested a role of total myostatin and activin A in models of age, whereas GDF11 contributed to the model of grip strength. Here we suggest a role for myostatin, activin A, and GDF11 in normal human aging that mirrors animal studies to date. Further interventional studies are required to elicitate the physiological role of these changes in the normal human aging process, and indeed if offsetting these changes can promote successful aging.

Effect of GDF11 on proliferation and apoptosis of esophageal cancer cells

This study was aimed at investigating the effect of growth differentiation factor 11 (GDF11) on the proliferation and apoptosis of esophageal cancer cells. Serum levels of GDF11 in esophageal cancer patients were determined with ELISA kits, and the correlation between serum GDF11 and pathological features of esophageal cancer were determined. The effect of recombinant GDF11 on the growth of esophageal cancer cells was measured by CCK6 method. In order to investigate the effect of recombinant GDF11 on the proliferation and apoptosis of esophageal cancer cells, the expression of apoptosis-promoting protein Bax and proliferative-associated protein Bcl-2 in esophageal cancer cells were determined using western blot. Moreover, GDF11 was used to treat esophageal cancer cells, and its effect on proliferation and apoptosis was determined with MTT assay and flow cytometry, respectively. The serum content of GDF11 was much less in esophageal cancer patients than in the control group. Esophageal GDF II in cancer patients was correlated with cancer differentiation: the higher the degree of differentiation, the higher the content of GDF11. GDF11 inhibits proliferation and apoptosis of esophageal cancer cells.

DKK1 and sclerostin are early markers of relapse in multiple myeloma

Recent studies have shown that Dickkopf-related protein (DKK1) and sclerostin decrease when a complete response (CR) is obtained after chemotherapy in myeloma multiple (MM). To study variations in DKK1, sclerostin and P1NP in patients treated for MM, between complete response (CR) and relapse, we carried out a prospective study ancillary to the IFM 2009 protocol (IFM). The aim of IFM was to compare progression-free survival between patients treated with chemotherapy with or without transplantation. We selected 69 patients who reached CR and relapsed. We assayed by ELISA: DKK1, sclerostin and P1NP at 3 end points T1: CR, T2: 4 months before relapse and T3: relapse. There was a significant increase in DKK1 and sclerostin between T1, T2 and T3. (DKK1 medians (IQR): T1 = 30 pmol/l (20.4-41.1), T2 = 37.4 pmol/l (29.8-49.4), p < 0.0001, T3 = 42 pmol/l (33.8-55.5), p < 0.0001 sclerostin medians (IQR): T1 = 0.57 (0.47-0.69), T2 = 0.62 ng/ml (0.53-0.79), p < 0.0001, T3 = n0.64 ng/ml (0.56-0.79), p = 0.005). No significant variation was detected in the levels of P1NP. No association was observed between the characteristics of the MM, or the treatment received and the variation between T1-T3 for DKK1, sclerostin or P1NP. A significant increase in DKK1 and sclerostin was observed four months before relapse.

A prospective study of the influence of the skeleton on calcium mass transfer during hemodialysis

BACKGROUND

Calcium gradient, the difference between serum calcium and dialysate calcium d[Ca], is the main contributor factor influencing calcium transfer during hemodialysis. The impact, however, of bone turnover, on calcium mass transfer during hemodialysis is still uncertain.

METHODS

This prospective cross-sectional study included 10 patients on hemodialysis for a 57.6±16.8 months, with severe hyperparathyroidism. Patients were submitted to 3 hemodialysis sessions using d[Ca] of 1.25, 1.5 and 1.75 mmol/l in three situations: pre-parathyroidectomy (pre-PTX), during hungry bone (early post-PTX), and after stabilization of clinical status (late post-PTX). Biochemical analysis and calcium mass transfer were evaluated and serum bone-related proteins were quantified.

RESULTS

Calcium mass transfer varied widely among patients in each study phase with a median of -89.5, -76.8 and -3 mmol using d[Ca] 1.25 mmol/L, -106, -26.8 and 29.7 mmol using d[Ca] 1.50 mmol/L, and 12.8, -14.5 and 38 mmol using d[Ca] 1.75 mmol/L during pre-PTX, early post-PTX and late post-PTX, respectively, which was significantly different among d[Ca] (p = 0.0001) and among phases (p = 0.040). Ca gradient and delta of Ca also differed among d[Ca] and phases (p<0.05 for all comparisons), whether ultrafiltration was similar. Serum Osteocalcin decreased significantly in late post-PTX, whereas Sclerostin increased earlier, in early post-PTX.

CONCLUSIONS

The skeleton plays a key role in Ca mass transfer during dialysis, either by determining pre-dialysis serum Ca or by controlling the exchangeable Ca pool. Knowing that could help us to decide which d[Ca] should be chosen in a given patient.

High levels of serum sclerostin and DKK1 in a case of Klippel-Trénaunay syndrome

Klippel-Trénaunay syndrome (KTS) is described as a complex syndrome characterized by various combinations of capillary, venous, and lymphatic malformations associated with bone and soft tissue hypertrophy. We report a case of a 67-year-old postmenopausal Caucasian women with KTS that shows elevated levels of sclerostin and Dickkopf-related protein 1 (DKK1). Dual-energy X-ray absorptiometry (DXA) BMD T-scores at lumbar spine and femur were normal. Serum calcium and phosphorus levels were consistently normal, 25-hydroxyvitamin D (25OHD) < 30 ng/mL, and normal parathyroid hormone (PTH). Turnover markers (serum osteocalcin [OCN], and carboxy-terminal cross-linking telopeptide of type 1 collagen [CTx]) were in the reference limits. It is interesting to note that the serum levels of sclerostin and DKK-1 were significantly higher in our patient with KTS than in a healthy volunteer (control), without impact on bone mineral density and bone formation markers. In fact, in our patient, the BMD at lumbar spine and femur was normal, and osteocalcin was not suppressed. Based on what is known, we would have expected to find low levels of the inhibitors of the Wnt system, perhaps we can explain the data as a response to the compensation for β-catenin hyper-transformation.

Circulating levels of sclerostin are associated with cardiovascular mortality

Cardiovascular diseases are a health problem throughout the world, especially in people with diabetes. The identification of cardiovascular disease biomarkers can improve risk stratification. Sclerostin is a modulator of the Wnt/β-catenin signalling pathway in different tissues, and it has recently been linked to vascular biology. The current study aimed to evaluate the relationship between circulating sclerostin levels and cardiovascular and non-cardiovascular mortality in individuals with and without type 2 diabetes. We followed up a cohort of 130 participants (mean age 56.8 years; 48.5% females; 75 with type 2 diabetes; 46 with prevalent cardiovascular disease) in which serum sclerostin levels were measured at the baseline. Time to death (both of cardiovascular and non-cardiovascular causes) was assessed to establish the relationship between sclerostin and mortality. We found that serum sclerostin concentrations were significantly higher in patients with prevalent cardiovascular disease (p<0.001), and independently associated with cardiovascular mortality (p = 0.008), showing sclerostin to be a stronger predictor of mortality than other classical risk factors (area under the curve = 0.849 vs 0.823). The survival analysis showed that an increase of 10 pmol/L in the serum sclerostin level resulted in a 31% increase in cardiovascular mortality. However, no significant association was observed between sclerostin levels and non-cardiovascular mortality (p = 0.346).

From these results, we conclude that high sclerostin levels are related to mortality due to cardiovascular causes. The clinical implication of these findings is based on the possible use of serum sclerostin as a new biomarker of cardiovascular mortality risk in order to establish preventive strategies.

A Prospective Cohort Study Showing No Association Between Serum Sclerostin Level and Mortality in Maintenance Hemodialysis Patients

BACKGROUND/AIMS

Potential relationships between serum sclerostin levels and the levels of bone metabolic markers in maintenance hemodialysis (MHD) patients have yet to be evaluated. This study sought to determine whether serum sclerostin levels are associated with mortality in MHD patients.

METHODS

We measured serum sclerostin levels in a Japanese MHD cohort, classified the patients into tertiles according to these levels, and followed their course for a 42-month period.

RESULTS

The cohort consisted of 389 MHD patients and there were 75 deaths. Kaplan-Meier analyses showed that the tertile of serum sclerostin was not associated with mortality risk. Cox analyses showed that there were no significant associations between serum sclerostin level and mortality.

CONCLUSION

Serum sclerostin level was not an independent predictor of mortality in MHD patients after adjustment for several confounders. However, whether clinical interventions to modulate serum sclerostin levels in MHD patients would improve their survival remains to be determined.

Validation of a novel, rapid, high precision sclerostin assay not confounded by sclerostin fragments

Sclerostin is a 190 amino acid protein secreted primarily by osteocytes. It was initially identified due to mutations in the SOST gene associated with high bone mass phenotypes. Much recent work has sought to determine the importance of sclerostin across an array of conditions which affect the human skeleton. However, accurate measurement of sclerostin from serum and plasma sources remains a significant impediment, with currently available commercial assays showing marked differences in measured sclerostin values. Accordingly, sclerostin assay standardization remains an important but unmet need before sclerostin measurements can be used for the clinical management of bone disease. Here we characterize a novel automated chemiluminescent sclerostin assay (LIAISON®, DiaSorin) which overcomes many of these limitations. Important assay characteristics include: a wide dynamic range (50-6500pg/mL); high intra- (<2.5%) and inter- (<5%) assay precision; matched serum and plasma equivalence (<10% difference); specificity for the intact sclerostin molecule; and rapid assay results. Serum sclerostin levels measured with the LIAISON® assay in a population-based sample of adult men (n=278) and women (n=348) demonstrated that sclerostin levels were significantly higher in men as compared to women and were positively associated with age in both sexes, consistent with previously published work. In postmenopausal women, serum sclerostin levels measured with the LIAISON® assay were reduced in response to treatment with either estrogen or teriparatide, again consistent with previous findings. Collectively, the above data demonstrate that the LIAISON® sclerostin assay provides a reliable tool for more confident assessment of emergent mechanisms wherein sclerostin may impact a number of bone related pathologies.

Effect of vitamin D supplementation on serum sclerostin levels in chronic kidney disease

Vitamin D deficiency, cardiovascular disease and abnormal bone mineral metabolism are common in chronic kidney disease (CKD). Abnormal bone mineral metabolism has been linked to vascular calcification in CKD. Sclerostin has emerged as an important messenger in cross talk between bone-vascular axis. We analyzed sclerostin in subjects who participated in the randomized, double blind, placebo controlled trial investigating the effect of cholecalciferol supplementation on vascular function in non-diabetic CKD stage G3-4 and vitamin D ≤ 20 ng/ml [CTRI/2013/05/003648]. Patients were randomized (1:1) to receive either two directly observed oral doses of 300,000 IU of cholecalciferol or matching placebo at baseline and 8 weeks. Of the 120 subjects enrolled, 58 in the cholecalciferol group and 59 in the placebo group completed the study. At baseline, serum levels of sclerostin were similar in both groups (cholecalciferol - median;190pg/ml, IQR;140-260 pg/ml and placebo - median;180 pg/ml, IQR; 140-240 pg/ml, p = 0.67). 16 weeks after cholecalciferol supplementation, there was no change in level of sclerostin (mean change;1.10 pg/ml, 95%CI; -27.34 to 29.34 pg/ml, p = 0.25). However, a significant decrease in sclerostin level was noted in the placebo group (mean change; -31.94 pg/ml, 95%CI; -54.76 to -9.13 pg/ml, p = 0.002). Change (Δ) in sclerostin level at 16 weeks correlated negatively with Δ eGFR (r = -0.20, p = 0.03) and positively with Δuric acid (r = 0.37, p < 0.001) but not with Δ25(OH) D (r = 0.06, p = 0.54), Δ iPTH (r = - 0.03, p = 0.78) ΔFGF23 (r = - 0.08, p = 0.38) and Δ125 (OH)₂ D (r = - 0.04, p = 0.65). In conclusion, high dose cholecalciferol supplementation did not change sclerostin levels in non-diabetic stage 3-4 CKD subjects.

Circulating sclerostin is not suppressed following a single bout of exercise in young men

The aim of this study was to determine whether an acute bout of exercise reduces serum sclerostin under diet-controlled conditions that stabilize the parathyroid hormone (PTH)-1,alpha-hydroxylase axis. Fourteen male volunteers (age, 22.1 years ± 4.05; BMI, 27.3 kg/m2  ± 3.8) completed a randomized crossover study in which they performed 10 sets of 10 repetitions of plyometric jumps at 40% of their estimated one-repetition maximum leg press or a nonexercise control period. A calcium-controlled diet (1000 mg/day) was implemented prior to, and throughout each study period. Blood was drawn for analysis of serum sclerostin, Dickkopf-1, markers of bone metabolism (PTH, calcium), markers of bone formation (bone alkaline phosphatase, BAP; osteocalcin, OCN), and markers of bone resorption (tartrate-resistant acid phosphatase 5b, TRAP5b; C-telopeptide cross-links of type I collagen, CTX) at baseline and 12, 24, 48, and 72 h following exercise or rest. Changes in serum concentrations were expressed as percentage change from individual baselines. Data were analyzed using a repeated measured linear mixed model to assess effects of time, physical activity status (rest or exercise condition), and the time by activity status interaction. There was a significant effect of exercise on OCN (P = 0.005) and a significant interaction effect for CTX (P = 0.001). There was no effect of exercise on any other biochemical marker of bone metabolism. A single bout of plyometric exercise did not induce demonstrable changes in biochemical markers of bone metabolism under conditions where dietary effects on PTH were controlled.

The effect of weight loss on body composition, serum bone markers, and adipokines in prepubertal obese children after 1-year intervention

Purpose/Aim: The influence of weight loss on bone turnover and bone quality in childhood remains controversial, but it may implicate interactions between adiposity and bone metabolism. Therefore, we studied the relationships between bone markers and adipokines during weight loss in obese children.

MATERIALS AND METHODS

We determined serum leptin, soluble leptin receptor, adiponectin, bone alkaline phosphatase (BALP), C-terminal telopeptide of type I collagen (CTX-I), osteocalcin (OC), carboxylated-OC (Gla-OC), undercarboxylated-OC (Glu-OC), sclerostin, body composition, and bone mineral density (BMD) in 40 obese prepubertal children before and after therapy. The control group, matched for sex and age, consisted of 40 non-obese children.

RESULTS

We found that values of the total body less head-bone mineral content (TBLH-BMC) and TBLH-BMD were significantly increased, but TBLH-BMD Z-score was decreased by 25% (p = 0.002) in obese children with weight loss after therapy. We observed increases of CTX-I to OC ratio (p = 0.009), and Gla-OC concentrations (p = 0.049). Changes in TBLH-BMD Z-score in patients were positively correlated with changes in BMI Z-score (p = 0.001), percentage of fat mass (p = 0.004), and BALP activity (p = 0.01). Changes in BALP activity were negatively correlated (p < 0.001) with changes in adiponectin concentrations, while changes in sclerostin levels were positively correlated (p = 0.001) with leptin changes.

CONCLUSIONS

We suggest that alterations in adipokines metabolism were associated with a lower rate of bone mineral accrual as a result of decreased bone formation rather than increased bone resorption. The lower rate of bone mass accrual in weight losing children may be an effect of reduced BALP levels related to increase in adiponectin levels.

Negative Association Between Sclerostin and INSL3 in Isolated Human Osteocytes and in Klinefelter Syndrome: New Hints for Testis-Bone Crosstalk

CONTEXT

The regulation of bone mass by the testis is a well-recognized mechanism, but the role of Leydig-specific marker insulin-like 3 peptide (INSL3) on the most abundant bone cell population, osteocytes, is unknown. In this study, we aimed to investigate the relationship between INSL3 and sclerostin, an osteocyte-specific protein that negatively regulates bone formation.

DESIGN

Serum sclerostin and INSL3 levels were evaluated in Klinefelter syndrome (KS) and healthy controls. In vitro effect of INSL3 on sclerostin production was evaluated in human cultured osteocytes.

PATIENTS

A total of 103 KS patients and 60 age- and sex-matched controls were recruited.

MAIN OUTCOME MEASURES

Serum sclerostin and INSL3 levels were assessed by enzyme-linked immunosorbent assay. Osteocytes were isolated by fluorescence-assisted cell sorting. Sclerostin expression was evaluated by western blot, immunofluorescence, and reverse transcription polymerase chain reaction. Measurement of bone mineral density was done by dual-energy X-ray absorptiometry at lumbar spine (L1-L4) and femoral neck.

RESULTS

Sclerostin levels were significantly increased in KS subjects, and negatively correlated with INSL3 levels in both cohorts and with bone mineral density in the KS group. Stimulation of cultured osteocytes with INSL3 at 10-7 M significantly decreased both sclerostin messenger RNA and protein expression.

CONCLUSIONS

We report a negative association between the testicular hormone INSL3 and the osteocytic negative regulator of bone formation, sclerostin. We further explored this association in vitro and showed that INSL3 was able to reduce sclerostin expression. These results add further knowledge on the emerging role of sclerostin as a therapeutic target for osteoporosis treatment.

Serum Sclerostin and Bone Turnover in Latent Autoimmune Diabetes in Adults

PURPOSE

Bone formation is impaired in both type 1 diabetes and type 2 diabetes (T2D), whereas sclerostin, an antagonist of bone formation, is increased in T2D only. No data are available on latent autoimmune diabetes in adults (LADA), an autoimmune type of diabetes that may clinically resemble T2D at diagnosis. We evaluated serum sclerostin and bone turnover markers in LADA compared with those in T2D and whether metabolic syndrome (MetS) affects sclerostin in T2D or LADA.

METHODS

This cross-sectional study included 98 patients with T2D and 89 with LADA from the Action LADA and Non Insulin Requiring Autoimmune Diabetes cohorts. Patients were further divided according to MetS status. Nondiabetic participants (n = 53) were used as controls. Serum sclerostin, bone formation (pro-collagen type 1 N-terminal propeptide [P1NP]), and bone resorption (C-terminal telopeptide of type I collagen [CTX]) were analyzed.

RESULTS

Patients with T2D had higher sclerostin than did those with LADA [P = 0.0008, adjusted for sex and body mass index (BMI)], even when analysis was restricted to patients with MetS (adjusted P = 0.03). Analysis of T2D and LADA groups separately showed that sclerostin was similar between those with and those without MetS. However, a positive trend between sclerostin and number of MetS features was seen with T2D (P for trend = 0.001) but not with LADA. Patients with T2D or LADA had lower CTX than did controls (P = 0.0003) and did not have significantly reduced P1NP. Sclerostin was unrelated to age or hemoglobin A1c but was correlated with BMI (ρ = 0.29; P = 0.0001), high-density lipoprotein (ρ = -0.23; P = 0.003), triglycerides (ρ = 0.19; P = 0.002), and time since diagnosis (ρ = 0.32; P < 0.0001).

CONCLUSIONS

Patients with LADA presented lower bone resorption than did controls, similar to patients with T2D. Sclerostin is increased in T2D but not in LADA, suggesting possible roles on bone metabolism in T2D only.

Physical inactivity is associated with decreased growth differentiation factor 11 in chronic obstructive pulmonary disease

BACKGROUND

Growth differentiation factor 11 (GDF11) is reported to possess anti-aging and rejuvenating effects, including muscle regeneration and to be highly expressed in skeletal muscle. Recently, we demonstrated that the levels of plasma GDF11 were decreased in COPD. However, the effect of decreased circulating GDF11 in the pathophysiology of COPD remains unknown. The aim of this study is to investigate the association between the plasma GDF11 levels and various clinical parameters in patients with COPD.

PATIENTS AND METHODS

Eighteen ex-smokers as control subjects and 70 COPD patients participated in the current study. We measured the levels of plasma GDF11 using immunoblotting, lung function, physical activity using a triaxial accelerometer, quadriceps strength, exercise capacity, and systemic inflammatory markers. We investigated the association between the levels of plasma GDF11 and these clinical parameters.

RESULTS

The levels of plasma GDF11 in the COPD patients had significant positive correlations with the data of lung function. Furthermore, the levels of plasma GDF11 were significantly correlated with the physical activity, quadriceps strength, and exercise capacity. Moreover, the levels of plasma GDF11 were significantly correlated with the data of inflammatory markers. Although various factors were related to GDF11, the multiple regression analysis showed that physical activity was significantly associated with the levels of plasma GDF11.

CONCLUSION

Physical inactivity was significantly related to the decreased GDF11 levels in COPD, which might be useful for understanding the pathogenesis of COPD. Clarifying the relationships between the physical inactivity and GDF11 may reveal a potentially attractive therapeutic approach in COPD via increasing the plasma levels of GDF11.

Effect of Teriparatide Treatment on Circulating Periostin and Its Relationship to Regulators of Bone Formation and BMD in Postmenopausal Women With Osteoporosis

CONTEXT

Treatment of postmenopausal osteoporosis with teriparatide parathyroid hormone amino terminal 1-34 increases bone formation and improves bone microarchitecture. A possible modulator of action is periostin. In vitro experiments have shown that periostin might regulate osteoblast differentiation and bone formation through Wnt signaling. The effect of teriparatide on periostin is not currently known.

OBJECTIVES

To determine the effect of teriparatide treatment on circulating levels of periostin and other regulators of bone formation and investigate how changes in periostin relate to changes in bone turnover markers, regulators of bone formation, and bone mineral density (BMD).

PARTICIPANTS AND DESIGN

Twenty women with osteoporosis; a 2-year open-label single-arm study.

INTERVENTION

Teriparatide 20 µg was administered by subcutaneous injection daily for 104 weeks. Periostin, sclerostin, and Dickkopf-related protein 1, procollagen type I N-terminal propeptide (PINP), and C-telopeptide of type I collagen were measured in fasting serum collected at baseline (two visits) and then at weeks 1, 2, 4, 12, 26, 52, 78, and 104. BMD was measured at the lumbar spine, total hip, and femoral neck using dual energy x-ray absorptiometry.

RESULTS

Periostin levels increased by 6.6% [95% confidence interval (CI), -0.4 to 13.5] after 26 weeks of teriparatide treatment and significantly by 12.5% (95% CI, 3.3 to 21.0; P < 0.01) after 52 weeks. The change in periostin correlated positively with the change in the lumbar spine BMD at week 52 (r = 0.567; 95% CI, 0.137 to 0.817; P < 0.05) and femoral neck BMD at week 104 (r = 0.682; 95% CI, 0.261 to 0.885; P < 0.01).

CONCLUSIONS

Teriparatide therapy increases periostin secretion; it is unclear whether this increase mediates the effect of the drug on bone.

Serum sclerostin in vascular calcification and clinical outcome in chronic kidney disease

Sclerostin, a potent soluble inhibitor of the Wnt signalling pathway, is known to inhibit bone formation by suppressing osteocytes differentiation and function. Patients with chronic kidney disease have high levels of serum sclerostin. Sclerostin has been implicated in the pathogenesis of vascular calcification, which may promote the cardiovascular events of morbidity and mortality in chronic kidney disease patients. However, the role of sclerostin in vascular calcification and clinical prognosis in chronic kidney disease remains elusive. While some studies suggested a positive correlation between serum sclerostin and vascular calcification or clinical outcome, other studies showed no or even negative correlation between them. Small sample size, heterogeneity in enrolled patients, discrepancy in anatomical structure examined and differences in the applied assays may be responsible for the discrepant results. Nonetheless, anti-sclerostin antibodies may be a new therapeutic approach to increase bone mass and strength in chronic kidney disease. This review aims to have a better understanding of the relationship of serum sclerostin with vascular calcification and clinical outcome in chronic kidney disease patients, and propose the application of anti-sclerostin therapy in chronic kidney disease.

Implication of osteoprotegerin and sclerostin in axial spondyloarthritis cardiovascular disease: study of 163 Spanish patients

OBJECTIVES

Due to the high incidence of cardiovascular disease in axial spondyloarthritis (axSpA), the search of potential biomarkers that may help to identify patients with high cardiovascular risk is of main importance. Therefore, in this study we assessed the implication of osteoprotegerin (OPG) and sclerostin (SCL), two biomarkers associated with cardiovascular disease and bone metabolism, in the clinical spectrum and atherosclerotic disease of patients with axSpA.

METHODS

OPG and SCL serum levels were determined in 163 axSpA Spanish patients (119 ankylosing spondylitis and 44 non-radiographic axSpA) and 63 healthy controls by enzyme-linked immunosorbent assay. Carotid ultrasound was performed in axSpA patients to determine the presence of subclinical atherosclerosis (by the identification of abnormally increased carotid intima-media thickness [cIMT] and presence of plaques).

RESULTS

Patients displayed higher OPG but lower SCL levels than controls (p=0.02 and 0.001, respectively). Association of these molecules with some metabolic syndrome features was seen. In this regard, OPG negatively correlated with body mass index (p=0.04) whereas SCL levels were higher in hypertensive patients (p=0.01) and in men (p=0.002). However, serum OPG and SCL were not significantly correlated with cIMT values or presence of plaques when data were adjusted by age at the time of the study, sex, classic cardiovascular risk factors and anti-TNF therapy.

CONCLUSIONS

Our results suggest an association of OPG and SCL in axSpA with some metabolic syndrome features that are associated with an increased risk of CV disease.

Targeted inhibition of sclerostin for post-menopausal osteoporosis therapy: A critical assessment of the mechanism of action

Promising news in the treatment of osteoporosis is that sequestering sclerostin from circulation with antibodies stimulates robust bone formation. Pre-clinical studies on rodents and monkeys have confirmed that treatment with anti-sclerostin monoclonal antibody (Scl-Ab) increases bone mass, improves bone strength and enhances fracture repair. Clinical trials show that bone gain (anabolic effect) is transient and are primarily at central (spine and hips) than peripheral (wrist) sites. Interestingly Scl-Ab also inhibited bone resorption. Thus Scl-Ab is being regarded as the pharmacologic agent with dual properties - stimulating bone formation and decreasing bone resorption. Sclerostin neutralization transiently increases bone formation markers in post-menopausal women and like parathyroid hormone (PTH) activates osteoblasts and lining cells resulting in bone anabolic effect. However, unlike PTH, sclerostin antibody also decreases bone resorption (anti-catabolic). Although, the U.S. Food and Drug Administration have accepted the Biologics License Application for one of the monoclonal antibodies against sclerostin (romosozumab) for review, many questions remain before romosozumab can be introduced as a skeletal anabolic agent to clinical practice. For example, neutralizing sclerostin alters calcium homeostasis and increases PTH. In addition, sclerostin depletion in preclinical studies has been reported to severely compromises B cell depletion in bone marrow. We have reviewed the currently available evidences that support the use of sclerostin antibody in treating osteoporosis and compare its efficacy and mechanism of action with the currently available anabolic drug, human PTH.

Splenectomy delays fracture healing by affecting the level of tumor necrosis factor alpha, interleukin 6 and bone morphogenetic protein

BACKGROUND

Abdominal injuries combined with bone fractures are increasing. Splenectomies are often required, but have prolonged healing time for bone fracture.

OBJECTIVES

The aim of the study was to explore the molecular mechanism for splenectomy delaying fracture healing.

MATERIAL AND METHODS

Eighty-four patients (42 received splenectomy) who received hip fractures operations were recruited in our hospital. One-year follow-up analysis was performed. To ensure the results, an animal model was established. Sprague-Dawley (SD) rats were randomly divided into 5 groups: group A: experimental group, femoral fractures + splenectomy; group B: femoral fractures; group C: splenectomy; group D: femoral fracture + sham splenectomy; group E: sham fracture. After the femoral fracture surgery, the callus status was evaluated by X-ray.

RESULTS

After 1-year follow-up, the healing index and bone quality was higher in the fracture-operatedonly group than in the splenectomy group. In contrast, the rate of healing complications was lower in the fracture-operated-only group than in the splenectomy group. Biomarker analysis showed that the serum levels of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and bone morphogenetic protein (BMP) were higher in the fracture-operated-only group than in the splenectomy group. No difference of the callus status was found among the rats in groups B, D and E (p > 0.05), while there were significant differences of the callus status of the rats in groups A and C at different stages (p < 0.05). On the other hand, the levels of TNF-α, IL-6 and BMP increased, reached peak after 7-day splenectomy surgery, and then decreased significantly in groups A and C (p > 0.05).

CONCLUSIONS

Splenectomy delays fracture healing by affecting the levels of TNF-α, IL-6 and BMP.

Role of sclerostin and dkk1 in bone remodeling in type 2 diabetic patients

PURPOSE

This study aimed to investigate the role of sclerostin and dkk1 in the bone metabolism of type 2 diabetic patients.

METHODS

This cross-sectional study included 95 inpatients with type 2 diabetes mellitus. We divided the patients into three groups (i.e., the normal bone mineral density (BMD) group, osteopenia group and osteoporosis group) based on their different BMD levels and measured the serum levels of sclerostin, dkk1, 25-hydroxyvitamin D₃ (25OHD₃), bone turnover markers and other biochemical data in each group.

RESULTS

Significantly increased levels of serum sclerostin and dkk1 were found in the osteoporosis group, even when the male and female cohorts were considered separately. Ordinal logistic regression analysis suggested that the levels of serum sclerostin were independently associated with the presence of osteopenia and osteoporosis after adjusting for age, gender and 25OHD₃ (sclerostin: OR = 1.02, p = 0.001). The areal BMDs were negatively correlated with the levels of serum sclerostin and dkk1 and positively correlated with 25OHD₃. In addition, age, glycosylated hemoglobin and serum sclerostin levels were predictors for N-terminal propeptide of type 1 procollagen and serum dkk1 levels were the only predictors for crosslinked carboxyterminal telopeptide in type 1 collagen.

CONCLUSIONS

The sclerostin and dkk1 levels increased in conjunction with the reduction of BMD, confirming that the Wnts, inhibited by sclerostin and dkk1, were potentially responsible for bone fragility in type 2 diabetes patients with osteoporosis. Note that the serum sclerostin levels were predictors for bone formation, while the DKK1 levels predicted bone resorption.

Two-year cortical and trabecular bone loss in CKD-5D: biochemical and clinical predictors

This prospective two-year study of patients on chronic dialysis measured changes in bone mineral density (BMD). Patients with higher baseline BMD and shorter dialysis vintage lost more bone. Treatment with anti-hypertensives acting on the central nervous system was protective against bone loss. Baseline serum levels of sclerostin and bone-specific alkaline phosphatase predicted bone loss.

INTRODUCTION

This prospective 2-year study of chronic kidney disease on dialysis (CKD-5D) patients assessed trabecular and cortical bone loss at the hip and spine and examined potential demographic, clinical, and serum biochemical predictors of bone loss.

METHODS

Eighty-nine CKD-5D patients had baseline, year 1, and year 2 bone mineral density (BMD) measurements using dual X-ray absorptiometry (DXA) and quantitative computed tomography (QCT); concurrent blood samples were drawn and clinical variables recorded. No study treatments occurred.

RESULTS

The 2-year total hip BMD change was - 5.9% by QCT and - 3.1% by DXA (p < 0.001). Spinal BMD was unchanged. QCT total hip cortical mass and volume decreased (- 7.3 and - 10.0%); trabecular volume increased by 5.9% (ps < 0.001). BMD changes did not vary with age, BMI, race, diabetes, smoking, or exercise. Patients with higher baseline BMD and shorter dialysis vintage lost more bone (p < 0.05). Vitamin D analogs and phosphate binders were not protective against bone loss; cinacalcet was protective by univariate but not by multivariable analysis. CNS-affecting antihypertensives were protective against loss of BMD, cortical mass, cortical volume (ps < 0.05) and trabecular mass (p = 0.007). These effects remained after adjustment. BSAP correlated with changes in BMD, cortical mass, and volume (p < 0.01) as did sclerostin (inversely).

CONCLUSIONS

There was severe cortical bone loss at the hip best recognized by QCT. Patients with shorter dialysis vintage and less pre-existing bone loss lost more bone, while treatment with CNS-acting antihypertensives was protective. BSAP and sclerostin were useful markers of bone loss.

24-hour profile of serum sclerostin and its association with bone biomarkers in men

The osteocyte's role in orchestrating diurnal variations in bone turnover markers (BTMs) is unclear. We identified no rhythm in serum sclerostin (osteocyte protein). These results suggest that serum sclerostin can be measured at any time of day and the osteocyte does not direct the rhythmicity of other BTMs in men.

INTRODUCTION

The osteocyte exerts important effects on bone remodeling, but its rhythmicity and effect on the rhythms of other bone cells are not fully characterized. The purpose of this study was to determine if serum sclerostin displays rhythmicity over a 24-h interval, similar to that of other bone biomarkers.

METHODS

Serum sclerostin, FGF-23, CTX, and P1NP were measured every 2 h over a 24-h interval in ten healthy men aged 20-65 years. Maximum likelihood estimates of the parameters in a repeated measures model were used to determine if these biomarkers displayed a diurnal, sinusoidal rhythm.

RESULTS

No discernible 24-h rhythm was identified for sclerostin (p = 0.99) or P1NP (p = 0.65). CTX rhythmicity was confirmed (p < 0.001), peaking at 05:30 (range 01:30-07:30). FGF-23 levels were also rhythmic (p < 0.001), but time of peak was variable (range 02:30-11:30). The only significant association identified between these four bone biomarkers was for CTX and P1NP mean 24-h metabolite levels (r = 0.65, p = 0.04).

CONCLUSIONS

Sclerostin levels do not appear to be rhythmic in men. This suggests that in contrast to CTX, serum sclerostin could be measured at any time of day. The 24-h profiles of FGF-23 suggest that a component of osteocyte function is rhythmic, but its timing is variable. Our results do not support the hypothesis that osteocytes direct the rhythmicity of other bone turnover markers (CTX), at least not via a sclerostin-mediated mechanism.

Sclerostin: Intracellular mechanisms of action and its role in the pathogenesis of skeletal and vascular disorders

Sclerostin is a glycoprotein involved in the regulation of bone metabolism, exclusively secreted by osteocytes. It affects the activity of bone morphogenetic proteins (BMPs) and is an inhibitor of the Wnt/β-catenin metabolic pathway in bone cells. Osteocytes reduce the release of sclerostin in response to mechanical stimuli acting on bone, and thus promote the activation of osteogenic pathway Wnt/β-catenin in osteoblasts. This signaling pathway plays a key role in osteogenesis and bone turnover. Loss of sclerostin gene function is related to 3 different craniotubular hyperostosis processes: sclerosteosis, craniodiaphyseal dysplasia, and van Buchem disease. Additionally, experimental and clinical studies suggest that sclerostin may promote vascular calcification. Antibodies directed against sclerostin stimulate bone formation and represent a new therapeutic option in the treatment of diseases with increased bone resorption, such as osteoporosis and inflammatory diseases where there is generalized bone loss, periarticular osteoporosis, and cartilage damage, such as rheumatoid arthritis (RA), ankylosing spondylitis (AS), and glucocorticoid-induced osteoporosis (GIO). Antibody use has the potential to offer new therapeutic approaches in the therapy of mineral and bone disorders resulting from chronic kidney disease (CKD-MBD) and vascular calcifications.

Hormonal responses following eccentric exercise in humans

OBJECTIVE

Mechanically overloaded muscle and its subsequent damage are strong stimuli for eliciting acute hormonal changes, while the muscle adaptation which occurs following exercise-induced muscle damage may involve complex hormonal responses before the completion of muscle regeneration. The purpose of this study was to investigate systemic responses of various hormones, as well as secreted proteins that are exercise-regulated and associated with muscle adaptation, for several days after eccentric exercise-induced muscle damage in humans.

DESIGN

Nine young male volunteers performed 50 maximal eccentric muscle actions using the knee extensor muscles of both legs. Blood samples were drawn before and at 6, 48 and 120 hours post exercise and serum levels of growth hormone (GH), insulin-like growth factor binding protein-3 (IGFBP-3), cortisol, prolactin, thyroid-stimulating hormone (TSH), free thyroxine (fT4), irisin, follistatin and sclerostin were measured. Myoglobin (Mb) concentration and lactate dehydrogenase (LDH) activity were also evaluated as indirect markers of muscle damage.

RESULTS

Significant alterations in Mb and LDH were observed over time after eccentric exercise (p=0.039-0.001). A late serum increase in fT4 and decrease in irisin levels, along with an early and persistent decrease in IGFBP-3 levels, were observed following the muscle-damaging exercise (p=0.049-0.016). GH, cortisol, prolactin, TSH, follistatin and sclerostin exhibited moderate changes during the recovery period after exercise, though without reaching statistical significance (p>0.05), while correlational analyses revealed significant associationsbetween GH and IGFBP-3, prolactin and sclerostin over time (p=0.049-0.001).

CONCLUSIONS

The significant hormonal responses observed in this study may indicate their involvement in the regenerative mechanisms following muscle damage, potentially as part of a regulatory network to support a normal adaptation process after muscle-damaging exercise.

Changes in expression of Wnt signaling pathway inhibitors dickkopf-1 and sclerostin before and after total joint arthroplasty

The aim is to study how serum concentration of Dickkopf-1 (DKK1) and Sclerostin (SOST) varies in patients before and after undergoing total joint arthroplasty (TJA). A total of 104 patients undergoing TJA were included in this study. Serum DKK1 and SOST were measured at 1 day before and 1, 3, and 5 days after surgery. DKK1 levels were highest at 5 days' postoperation, increasing to 25.17% above preoperation levels (P < .01), while SOST levels were lowest at 3 days' postoperation, falling to 18.71% below preoperation levels (P < .05). Serum levels of DKK1 and SOST showed opposite trends in the days following TJA. Our research describes for the first time the perioperative changes observed in serum DKK1 and SOST levels of osteoarthritis (OA) patients undergoing TJA. Increased DKK1 and decreased SOST levels may help maintain the equilibrium of the WNT pathway in OA patient's postsurgery.

Circulating levels of dickkopf-1, osteoprotegerin and sclerostin are higher in old compared with young men and women and positively associated with whole-body bone mineral density in older adults

Bone mineral density declines with increasing older age. We examined the levels of circulating factors known to regulate bone metabolism in healthy young and older adults. The circulating levels of dickkopf-1, osteocalcin, osteoprotegerin and sclerostin were positively associated with whole-body bone mineral density (WBMD) in older adults, despite the average WBMD being lower and circulating dickkopf-1, osteoprotegerin and sclerostin being higher in old than young.

INTRODUCTION

This study aims to investigate the relationship between whole-body bone mineral density (WBMD) and levels of circulating factors with known roles in bone remodelling during 'healthy' ageing.

METHODS

WBMD and fasting plasma concentrations of dickkopf-1, fibroblast growth factor-23, osteocalcin, osteoprotegerin, osteopontin and sclerostin were measured in 272 older subjects (69 to 81 years; 52% female) and 171 younger subjects (18-30 years; 53% female).

RESULTS

WBMD was lower in old than young. Circulating osteocalcin was lower in old compared with young, while dickkopf-1, osteoprotegerin and sclerostin were higher in old compared with young. These circulating factors were each positively associated with WBMD in the older adults and the relationships remained after adjustment for covariates (r values ranging from 0.174 to 0.254, all p < 0.01). In multivariate regression, the body mass index, circulating sclerostin and whole-body lean mass together accounted for 13.8% of the variation with WBMD in the older adults. In young adults, dickkopf-1 and body mass index together accounted for 7.7% of variation in WBMD.

CONCLUSION

Circulating levels of dickkopf-1, osteocalcin, osteoprotegerin and sclerostin are positively associated with WBMD in community-dwelling older adults, despite the average WBMD being lower and circulating dickkopf-1, osteoprotegerin and sclerostin being higher in old than young.

Normal bone density and trabecular bone score, but high serum sclerostin in congenital generalized lipodystrophy

CONTEXT

Berardinelli-Seip Congenital Lipodystrophy (BSCL) is a rare autosomal recessive syndrome characterized by a difficulty in storing lipids in adipocytes, low body fat mass, hypoleptinemia, and hyperinsulinemia. Sclerostin is a product of SOST gene that blocks the Wnt/β-catenin pathway, decreasing bone formation and enhancing adipogenesis. There are no data about sclerostin in people with BSCL.

OBJECTIVE

We aimed to evaluate serum sclerostin, bone mineral density (BMD), and L1-L4 Trabecular Bone Score (TBS) in BSCL patients, generating new knowledge about potential mechanisms involved in the bone alterations of these patients.

DESIGN, SETTING, AND PATIENTS

In this cross-sectional study, we included 11 diabetic patients with BSCL (age 24.7±8.1years; 6 females). Sclerostin, leptin, L1-L4 TBS, BMD were measured. Potential pathophysiological mechanisms have been suggested.

RESULTS

Mean serum sclerostin was elevated (44.7±13.4pmol/L) and was higher in men than women (55.3±9.0 vs. 35.1±8.4pmol/L, p=0.004). Median of serum leptin was low [0.9ng/mL (0.5-1.9)]. Seven out of 11 patients had normal BMD, while four patients had high bone mass (defined as Z-score>+2.5SD). Patients on insulin had lower sclerostin (37.3±9.2 vs. 52.6±13.4pmol/L, p=0.05). The mean TBS was 1.402±0.106, and it was higher than 1.300 in nine patients.

CONCLUSIONS

Patients with lipoatrophic diabetes (BSCL) have high serum concentrations of sclerostin, normal or high BMD, and reasonable trabecular bone mass measured by TBS. This is the first report of high sclerostin and good bone microarchitecture (TBS) in BSCL patients.

Serum Sclerostin Increases After Acute Physical Activity

Physical activity has a major impact on bone density and on osteoporosis prevention. Sclerostin is produced by osteocytes and inhibits bone formation. The impact of exercise on sclerostin secretion has not been studied so far. This pilot study aimed to explore circulating sclerostin levels immediately after acute exercise. Healthy young women practicing physical activity less than 120 min per week were enrolled. The exercise was a 45-min, low-speed, treadmill running test. Blood samples were taken at rest before exercise and within 5 min after the end of exercise. We assessed serum creatinine, 25-OH vitamin D, alkaline phosphatase, C-telopeptide of type I collagen, bone-specific alkaline phosphatase, and sclerostin. Sclerostin stability at rest was also validated over the same period of time among women fulfilling the same inclusion criteria. The study included 23 participants (mean ± SD age: 22.9 ± 1.5 years) for the exercise test and 9 participants for the resting test (26.1 ± 3.1 years). There was no difference in body mass index between the two groups. Sclerostin increased after exercise in comparison to baseline (mean ± SEM: 410 ± 27 vs. 290 ± 19 pg/mL; p < 0.001) corresponding to an increase of +44.3 ±5.5%. In the resting test, sclerostin remained stable (303 ± 20 vs. 294 ± 20 pg/mL, p = 0.76). There was a substantial increase in serum sclerostin in untrained healthy young women immediately after physical activity. These results suggest the existence of an acute release of systemic sclerostin in response to physical activity.

Varying Patterns of Biomarkers of Mineral and Bone Metabolism After Kidney Transplantation

Sclerostin inhibits Wnt/β-catenin signaling pathway, thereby decreasing bone formation. Osteoblast stimulating actions of parathyroid hormone (PTH) are mediated by suppression of sclerostin. Thus, sclerostin may reflect both bone metabolism and parathyroid function. The study was aimed to analyze the patterns of the changes of mineral and bone biomarkers for 9 months following kidney transplantation (KTx). Thirty-five patients after KTx were included into a 9-month observational study. Serum creatinine, calcium, phosphorus, 25-OH vitamin D, PTH, fibroblast growth factor 23 (FGF-23), sclerostin, and bone-specific alkaline phosphatase (BAP) were measured before KTx, and 1, 2 weeks, and 1, 2, 3, 4, 5, 6, and 9 months thereafter. Urine sclerostin/creatinine ratio was assessed in parallel from month 1 after KTx. Following KTx most serum markers significantly decreased till the end of observation including PTH (by 58%), phosphorus (37%), sclerostin (31%), BAP (28%), and FGF-23 (82%). Most of the decrease was observed during first 2 months after KTx. Serum calcium was increased by 17%. Urine sclerostin/creatinine ratio increased from month 1 till month 6. At KTx serum FGF-23 correlated only with phosphate (r=0.62, p=0.01) and PTH with BAP (r=0.49, p=0.04) but not with sclerostin. At the end of the study neither serum sclerostin nor FGF-23 correlated with other parameters of mineral and bone metabolism. Sclerostin shows the limited utility as the marker of the resolution of bone and mineral metabolism after KTx.