Lower uncarboxylated osteocalcin and higher sclerostin levels are significantly associated with coronary artery disease

Association between bone mineral density and coronary plaque burden in patients with coronary artery disease: a cross-sectional study using quantitative computed tomography

PURPOSE

To evaluate the association between osteoporosis and coronary calcification and coronary plaque burden in patients with atherosclerosis and coronary artery disease (CAD).

METHODS

This study included 290 men and 177 postmenopausal women with angiography-confirmed atherosclerosis or CAD who underwent chest multidetector row computed tomography covering L1-L2 between September 2020 and October 2021. Quantitative computed tomography was used to measure the lumbar vertebra's bone mineral density (BMD). The coronary artery calcium score (CACS) and total coronary plaque burden were quantified using the Agatston and modified Gensini scores, respectively. Associations between BMD and CACS and modified Gensini scores were assessed using multivariate regression analysis. Lasso regression was used in model selection.

RESULTS

In men, BMD was inversely associated with CACS [ β  = -0.24; 95% confidence interval (CI), -0.35 to -0.13; P  < 0.001) and coronary artery calcification (CAC) presence [odds ratio (OR) = 0.71; 95% CI, 0.52-0.96; P  = 0.03) in the unadjusted model. After adjusting for age, modified Gensini score, prior percutaneous coronary intervention and hypertension, BMD was inversely associated with CACS ( β  = -0.11; 95% CI, -0.22 to -0.01; P  = 0.04). In postmenopausal women, BMD was inversely associated with CACS ( β  = -0.24; 95% CI, -0.39 to 0.10; P  < 0.001) and CAC presence (OR = 0.66; 95% CI, 0.47-0.92; P  = 0.01) in the unadjusted model but no other models ( P  > 0.05). In both sexes, BMD did not correlate with the modified Gensini score or CAD prevalence (all P  > 0.05).

CONCLUSION

In patients with coronary atherosclerosis and CAD, BMD of the lumbar vertebra correlated inversely with CACS in men but not postmenopausal women. Additionally, BMD did not correlate with the modified Gensini score in both sexes.

Serum biomarkers for arterial calcification in humans: A systematic review

Aim

To clarify the role of mediators of ectopic mineralization as biomarkers for arterial calcifications.

Methods

MEDLINE and Embase were searched for relevant literature, until January 4th 2022. The investigated biomarkers were: calcium, phosphate, parathyroid hormone, vitamin D, pyrophosphate, osteoprotegerin, receptor activator of nuclear factor-kappa B ligand (RANKL), fibroblast growth factor-23 (FGF-23), Klotho, osteopontin, osteocalcin, Matrix Gla protein (MGP) and its inactive forms and vitamin K. Studies solely performed in patients with kidney insufficiency or diabetes mellitus were excluded.

Results

After screening of 8985 articles, a total of 129 articles were included in this systematic review. For all biomarkers included in this review, the results were variable and more than half of the studies for each specific biomarker had a non-significant result. Also, the overall quality of the included studies was low, partly as a result of the mostly cross-sectional study designs. The largest body of evidence is available for phosphate, osteopontin and FGF-23, as a little over half of the studies showed a significant, positive association. Firm statements for these biomarkers cannot be drawn, as the number of studies was limited and hampered by residual confounding or had non-significant results. The associations of the other mediators of ectopic mineralization with arterial calcifications were not clear.

Conclusion

Associations between biomarkers of ectopic mineralization and arterial calcification are variable in the published literature. Future longitudinal studies differentiating medial and intimal calcification could add to the knowledge of biomarkers and mechanisms of arterial calcifications.

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We researched the association between biomarkers and arterial calcifications.

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This review focused on biomarkers of bone metabolism and Matrix Gla protein.

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Associations between biomarkers and arterial calcification are variable.

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Future studies should differentiate between medial and intimal calcifications.

The Association of Coronary Artery Calcium Score and Osteoporosis in Postmenopausal Women: A Cross-Sectional Study

BACKGROUND

The association between osteoporosis, a common metabolic bone disorder, and atherosclerosis has been reported in different studies. In this study, we aimed to investigate the association between the coronary artery calcium score (CACS) and bone mineral density (BMD) at different sites and bone biomarkers in postmenopausal women.

METHODS

A total of 184 participants were enrolled in this study. The CACS and BMD at different sites, including the spinal, total hip, and femoral neck, were measured using computed tomography angiography and dual energy X-ray absorptiometry, respectively. Serum levels of osteocalcin, β-C-terminal telopeptide (β-CTX), parathyroid hormone, and 25-hydroxy-vitamin D were measured.

RESULTS

A negative association between CACS and bone biomarker levels (osteocalcin, P=0.021; β-CTX, P=0.013) was noted. The univariable model showed an association between CACS and osteoporosis of the femoral neck (P=0.03). It was found that with an increase of 10 U in CACS, the odds of osteoporosis at the femoral neck escalates by 2% (odds ratio=1.02, 95% confidence interval, 1.002-1.03) using the multivariate logistic regression model, while such an association with osteoporosis could not be found at the spinal site. The best cutoff point of the calcium score was estimated to be 127.

CONCLUSIONS

The results suggest that in postmenopausal women, coronary atherosclerosis is independently associated with osteoporosis of the femoral neck, but such an association could not be detected with spinal osteoporosis. The importance of screening for osteoporosis in patients with cardiovascular disease and the implications of preventive measures in the primary care setting were highlighted considering the common risk factors.

Role of Sclerostin in Cardiovascular Disease

Sclerostin is most recognized for its role in controlling bone formation but is also expressed in the heart, aorta, coronary, and peripheral arteries. This review summarizes research on sclerostin's role in cardiovascular disease. Rodent studies have found sclerostin to be expressed at sites of arterial calcification. In contrast, aortic sclerostin was reported to be downregulated in a mouse model of abdominal aortic aneurysm, and transgenic upregulation or administration of sclerostin was found to prevent abdominal aortic aneurysm and atherosclerosis formation. Sclerostin deficiency was reported to stimulate cardiac rupture in one rodent model. In humans, 7 of 11 studies reported a significant association between high serum sclerostin and high carotid intima media thickness. Ten of 15 studies reported a significant association between high serum sclerostin and severe arterial calcification. Twelve of 14 studies reported a significant association between high serum sclerostin and high arterial stiffness or atherosclerosis severity. Four of 9 studies reported a significant association between high serum sclerostin and high risk of cardiovascular events. A meta-analysis of randomized controlled trials suggested that administration of the sclerostin blocking antibody romosozumab did not significantly increase the risk of major adverse cardiovascular events (risk ratio, 1.14 [95% CI, 0.83-1.57]; P=0.54) or cardiovascular death (risk ratio, 0.92 [95% CI, 0.53-1.59]; P=0.71). Human genetic studies reported variants predisposing to low arterial sclerostin expression were associated with a high risk of cardiovascular events. Overall, past research suggests a cardiovascular protective role of sclerostin but findings have been inconsistent, possibly due to variations in study design, the unique populations and models studied, and the heterogeneous methods used.

Osteocalcin association with vascular function in chronic kidney disease

Osteocalcin (OCN) is a bone‐derived and vitamin K dependent hormone that affects energy metabolism and vascular calcification. The relationship between serum OCN and vascular function in patients with chronic kidney disease (CKD) is uncertain. This study investigated the association between serum OCN and vascular function as expressed with reactive hyperemia index (RHI) and augmentation index (AIx) measured by Endo‐PAT 2000 device. This cross‐sectional analysis was based on 256 pre‐dialysis CKD patients who had completed the Endo‐PAT 2000 test and serum OCN at the First Center of Chinese PLA Hospital from November 2017 to December 2019. Based on whether the RHI was less than 1.67, the patients were divided into endothelial dysfunction and normal endothelial function groups. Multiple logistic and linear regression were used to analyze the association between OCN and vascular function. Subgroup analyses were performed to examine the effects of OCN on vascular function in different CKD populations. After multivariate adjustment, CKD with low OCN were more likely to have endothelial dysfunction (OR: 0.794; 95%CI: 0.674‐0.934; P = .006); on the contrary, patients with high OCN had a higher degree of arterial stiffness (standardized β: 0.174; P = .003). Subgroup analyses showed that higher OCN was associated with severe arterial stiffness but a better endothelial function in young (age < 65 years, P_RHI/P_AIx@75 = .027/.011), male (P_RHI/P_AIx@75 = .040/.016), patients with a history of hypertension (P_RHI/P_AIx@75 = .004/.009) or diabetes (P_RHI/P_AIx@75 = .005/.005), and in early CKD (P_RHI/P_AIx@75 = .014/.015). In conclusion, serum OCN correlates with vascular function in CKD patients: beneficial for endothelial function but detrimental to arterial stiffness.

Joint Association of Low Vitamin K1 and D Status With First Stroke in General Hypertensive Adults: Results From the China Stroke Primary Prevention Trial (CSPPT)

Background

Vitamin K plays a role in preventing vascular calcification and may have a synergetic influence with vitamin D on cardiovascular health. However, whether this relationship applies to stroke, especially in a high-risk population of hypertensive individuals, remains unclear. The present study aims to study the joint association of low vitamin K1 and D status with first stroke in general hypertensive adults.

Methods

This study used a nested, case-control design with data from the China Stroke Primary Prevention Trial. The analysis included 604 first total stroke patients and 604 matched controls from a Chinese population with hypertension. Odds ratios (ORs) and 95% confidence intervals were calculated using conditional logistic regression.

Results

There was a non-linear negative association between plasma vitamin K1 and the risk of first total stroke or ischemic stroke in the enalapril-only group. Compared to participants in vitamin K1 quartile 1, a significantly lower risk of total stroke (OR = 0.58, 95% CI: 0.36, 0.91, P = 0.020) or ischemic stroke (OR = 0.34, 95% CI: 0.17, 0.63, P < 0.001) was found in participants in vitamin K1 quartile 2-4 in the enalapril-only group. When further divided into four subgroups by 25(OH)D and vitamin K1, a significantly higher risk of total stroke or ischemic stroke was observed in participants with both low vitamin K1 and 25(OH)D compared to those with both high vitamin K1 and 25(OH)D in the enalapril-only group. No increased risk was observed in the groups low in one vitamin only.

Conclusion

Low concentrations of both vitamin K1 and 25(OH)D were associated with increased risk of stroke.

Uncarboxylated osteocalcin promotes osteogenesis and inhibits adipogenesis of mouse bone marrow-derived mesenchymal stem cells via the PKA-AMPK-SIRT1 axis

Osteoporosis is a bone disease characterized by reduced bone density, thin cortical bone and large gaps in the bone's honeycomb structure, which increases the risk of bone fragility. Uncarboxylated osteocalcin (unOC), a vitamin K-dependent bone protein, is known to regulate carbohydrate and energy metabolism. A previous study demonstrated that unOC promotes the differentiation of mouse bone marrow-derived mesenchymal stem cells (BMSCs) into osteoblasts, but inhibits their differentiation into adipocytes. However, the underlying mechanism remains unknown. The present study showed that unOC regulated the differentiation potential of BMSCs via protein kinase A (PKA)/AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) signaling. SIRT1, a member of the sirtuin family with deacetylation functions, was upregulated by unOC in BMSCs. Transfection analyses with SIRT1 small interfering RNA indicated that the unOC-induced differentiation shift in BMSCs required SIRT1. Examination of SIRT1 downstream targets revealed that unOC regulated the acetylation levels of runt-related transcription factor (RUNX) 2 and peroxisome proliferator-activated receptor γ (PPARγ). Therefore, unOC inhibited adipogenic differentiation by PPARγ acetylation and promoted osteogenic differentiation by RUNX2 deacetylation. Moreover, phosphorylated PKA and AMPK protein levels increased after unOC treatment, which led to the upregulation of SIRT1. Western blot analysis with PKA and AMPK inhibitors indicated that the PKA-AMPK signaling pathway functioned upstream of SIRT1 and positively regulated SIRT1 expression. These findings led us to propose a model in which unOC regulated BMSC osteogenic differentiation through the PKA-AMPK-SIRT1 axis, giving evidence towards the therapeutic potential of unOC in osteoporosis treatment.

Osteocalcin and Non-Alcoholic Fatty Liver Disease: Lessons From Two Population-Based Cohorts and Animal Models

Osteocalcin regulates energy metabolism in an active undercarboxylated/uncarboxylated form. However, its role on the development of non-alcoholic fatty liver disease (NAFLD) is still controversial. In the current study, we investigated the causal relationship of circulating osteocalcin with NAFLD in two human cohorts and studied the effect of uncarboxylated osteocalcin on liver lipid metabolism through animal models. We analyzed the correlations of serum total/uncarboxylated osteocalcin with liver steatosis/fibrosis in a liver biopsy cohort of 196 participants, and the causal relationship between serum osteocalcin and the incidence/remission of NAFLD in a prospective community cohort of 2055 subjects from Shanghai Changfeng Study. Serum total osteocalcin was positively correlated with uncarboxylated osteocalcin (r = 0.528, p < .001). Total and uncarboxylated osteocalcin quartiles were inversely associated with liver steatosis, inflammation, ballooning, and fibrosis grades in both male and female participants (all p for trend <.05). After adjustment for confounding glucose, lipid, and bone metabolism parameters, the male and female participants with lowest quartile of osteocalcin still had more severe liver steatosis, with multivariate-adjusted odds ratios (ORs) of 7.25 (1.07-49.30) and 4.44 (1.01-19.41), respectively. In the prospective community cohort, after a median of 4.2-year follow-up, the female but not male participants with lowest quartile of osteocalcin at baseline had higher risk to develop NAFLD (hazard ratio [HR] = 1.90; 95% confidence interval [CI] 1.14-3.16) and lower chance to achieve NAFLD remission (HR = 0.56; 95% CI 0.31-1.00). In wild-type mice fed a Western diet, osteocalcin treatment alleviated hepatic steatosis and reduced hepatic SREBP-1 and its downstream proteins expression. In mice treated with osteocalcin for a short term, hepatic SREBP-1 expression was decreased without changes of glucose level or insulin sensitivity. When SREBP-1c was stably expressed in a human SREBP-1c transgenic rat model, the reduction of lipogenesis induced by osteocalcin treatment was abolished. In conclusion, circulating osteocalcin was inversely associated with NAFLD. Osteocalcin reduces liver lipogenesis via decreasing SREBP-1c expression. © 2020 American Society for Bone and Mineral Research (ASBMR).

Serum osteocalcin is inversely associated with lower extremity atherosclerotic disease in Chinese patients with type 2 diabetes mellitus

Serum osteocalcin (OCN) is closely related to metabolic risk factors, and the relationship between OCN and atherosclerosis has been investigated. However, it is still controversial. Herein, we explored the potential correlation between serum total OCN and lower extremity atherosclerotic disease (LEAD) in 326 hospitalized Chinese patients with type 2 diabetes mellitus (T2DM). Femoral intima-media thickness (F-IMT) and lower limb atherosclerotic plaque were assessed through color Doppler ultrasound. Subjects with LEAD had significantly lower serum OCN levels compared with those without LEAD (14.54 [14.10-14.89] ng/mL versus 16.79 [15.86-18.04] ng/mL, p < 0.001). Spearman's correlation analysis revealed that serum OCN levels were positively associated with high density lipoprotein cholesterol (HDL-C) and negatively associated with fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG), hemoglobin A1c (HbA1c), waist-to-hip ratio (WHR) and F-IMT. Multiple logistic analysis revealed that OCN (OR 0.938, 95% confidence interval (CI 0.933-0.950, p = 0.003) and glomerular filtration rate (GFR) (OR 0.990, 95% CI 0.985-0.996, p = 0.003) were independently and inversely associated with LEAD, while age (OR 1.140, 95% CI 1.127-1.148, p < 0.001), diabetes duration (OR 1.068, 95% CI 1.039-1.080, p < 0.005) and uric acid (UA) (OR 1.005, 95% CI 1.002-1.007, p = 0.032) were independently and positively associated with LEAD. Additionally, multiple linear regression analysis revealed that serum OCN levels were negatively associated with F-IMT (standardized β = -0.180, p = 0.002). In Chinese patients with T2DM, serum OCN levels were independently and inversely correlated with LEAD.

Osteocalcin and vascular calcification in hemodialysis patients: an observational cohort study

BACKGROUND

Vascular calcification contributes to morbidity and mortality in patients with ESRD on maintenance hemodialysis.

AIMS

To study the relationship between osteocalcin and vascular calcification.

METHODS

160 patients with ESRD on maintenance hemodialysis and 60 age-and sex-matched healthy controls were recruited. Serum vitamin K2 and osteocalcin both intact and undercarboxylated were measured. Transthoracic echocardiography was done for valvular calcification and thickening, and carotid duplex was done for carotid intimal medial calcification and thickening.

RESULTS

Hemodialysis patients have higher median serum vitamin K2 (p < 0.001), higher undercarboxylated osteocalcin (p < 0.001). Only older age, duration of hypertension, and duration of established cardiovascular disease are associated with carotid media-intimal calcification. Old age is a strong predictor of carotid media intimal thickening. Female sex is associated with a valvular thickening.

CONCLUSIONS

Functional vitamin K deficiency is present in maintenance hemodialysis patients and serum osteocalcin is not associated with cardiovascular calcification.

The Effect of Recombinant Undercarboxylated Osteocalcin on Endothelial Dysfunction

Low circulating levels of undercarboxylated osteocalcin (ucOC) is associated with a higher risk of cardiovascular disease, yet whether ucOC has a direct effect on endothelium-dependent vasorelaxation, or in proximity to its postulated receptor, the class CG protein-coupled receptor (GPCR6A), in blood vessels remains unclear. Immunohistochemistry and proximity ligation assays were used to localize the presence of ucOC and GPRC6A and to determine the physical proximity (< 40 nm) in radial artery segments collected from patients undergoing coronary artery bypass surgery (n = 6) which exhibited calcification (determined by Von Kossa) and aorta from New Zealand white rabbits exhibiting atherosclerotic plaques. Endothelium-dependent vasorelaxation was assessed using cumulative doses of acetylcholine in vitro on abdominal aorta of rabbits fed a normal chow diet (n = 10) and a 4-week atherogenic diet (n = 9) pre-incubated with ucOC (10 ng/mL) or vehicle. Both ucOC and GPRC6A were localized in human and rabbit diseased-blood vessels. Proximity ligation assay staining demonstrated physical proximity of ucOC with GPRC6A only within plaques in rabbit arteries and the endothelium layer of rabbit arterioles. Endothelium-dependent vasorelaxation was impaired in atherogenic abdominal aorta compared to healthy aorta and ucOC attenuated this impairment. ucOC attenuated impaired endothelium-dependent vasorelaxation in rabbit abdominal aorta following an atherogenic diet, however, this effect may be independent of GPRC6A. It is important that future studies determine the underlying cellular mechanisms by which ucOC effects blood vessels as well as whether it can be used as a therapeutic agent against the progression of atherosclerosis.

Bone mass density and bone metabolism marker are associated with progression of carotid and cardiac calcified plaque in Chinese elderly population

Osteoporosis and cardiovascular diseases often coexist in the same elderly individuals. Does this suggest some potential correlation between the two diseases? Low bone mass and change of bone biomarker are associated with a higher risk of carotid and cardiac calcification plaques.

INTRODUCTION

Bone mineral density (BMD) and bone metabolism marker may contribute to the progression of carotid and cardiac arterial calcifications. The aim of this study was to investigate whether low bone mass and the change of bone biomarker are associated with the prevalence of calcified atherosclerotic plaque in elderly Chinese.

METHODS

We conducted a five-year prospective study. BMD was measured by dual-energy X-ray absorptiometry scanning. Carotid and cardiac computed tomography angiography (CTA) was conducted using a 64-multidetector row scanner to assess carotid and cardiac arterial plaque at baseline and during follow-up.

RESULTS

Of 1571 community residents over 60 years of age, 184 (11.7%) subjects developed carotid calcified plaque, 510 (32.5%) subjects developed cardiac calcified plaque and 97 (6.2%) subjects developed co-existence calcified plaques in carotid and cardiac arteries. After adjustment for age and all relevant confounders, Q1, Q2 quartile of BMD, and osteoprotegerin (OPG), osteocalcin (OC), and C-terminal cross-linked telopeptide of type I collagen (CTX) were associated with increased risk of calcified plaques.

CONCLUSION

This study suggested that lower BMD and change of bone metabolism biomarker were associated with a higher risk of carotid and cardiac calcified plaque development.

Osteocalcin and epicardial adipose tissue in obesity: new hints for epicardial adipose tissue-bone crosstalk

Objectives: Osteocalcin (OC) appears to be involved in the regulation of glucose and fat metabolism. We aimed to determine the association between OC and epicardial adipose tissue (EAT) in premenopausal obese women. Design: The study included 73 premenopausal obese women and 55 non-obese women. Echocardiographic examination was performed to measure EAT. Serum OC levels were measured by chemiluminescence immunoassay. Results: OC levels were significantly lower in obese women than controls (18.26 ± 5.27 vs. 22.53 ± 6.84 ng/ml, p < .001). EAT thickness was higher in obese women than controls (5.19 ± 0.73 vs. 3.25 ± 1.35 mm, p < .001). In obese women, OC was positively correlated with EAT thickness (p = .043; r = 0.326). There was no correlation in controls. Conclusions: Premenopausal obese women had lower OC levels and thicker EAT than controls. There was a weak positive correlation between OC and EAT in premenopausal obese women. This potential cross talk between bone metabolism and EAT could play a role in the development of atherosclerosis in obesity.

Serum osteocalcin level as an indicator of low-grade albuminuria in Chinese men free of kidney disease

OBJECTIVE

The presence of low-grade albuminuria (LGA) suggested that the pathophysiology of vascular dysfunction has been initiated. Clear evidence supports a role for osteocalcin in energy metabolism and a great incidence of pathological cardiovascular changes. The observational community-based study aims to examine the association of osteocalcin with LGA, which may provide new insight into potential involvement of osteocalcin in cardiovascular diseases.

METHODS

A total of 1951 adults [58.37 (53.34-63.13) years, 41.3% men] from Shanghai were enrolled. LGA was defined as a urinary albumin-to-creatinine ratio (UACR) < 30 mg/g. Serum osteocalcin was measured using an electrochemiluminescence immunoassay.

RESULTS

Serum osteocalcin level in men decreased with increasing UACR after adjusting for potential covariates (p = 0.045); however, the adjusted association disappeared in women (p = 0.258). Linear regression analysis showed that osteocalcin was a negative variable of UACR in men (standardized β = -0.074, p = 0.030), particularly prominent in non-hyperglycemic, non-hypertensive men, even regardless of estimated glomerular filtration rate (eGFR) (60 ≤ eGFR <90 mL/min/1.73 m², standardized β =-0.422, p = 0.004; ≥ 90 mL/min/1.73 m², standardized β = -0.167, p = 0.037).

CONCLUSION

After controlling for confounders, serum osteocalcin level was independently associated with LGA in men, which suggested that osteocalcin was closely related with atherosclerosis and vascular dysfunction.

Peripheral artery disease and osteoporosis: Not only age‑related (Review)

Osteoporosis and atherosclerosis are two chronic degenerative diseases that share several biochemical pathways and risk factors. Previous studies have associated osteoporosis with carotid atherosclerosis, cardiovascular mortality and stroke, but data on the relationship with peripheral artery disease are few and conflicting. The OPG/RANK/RANKL system and Wnt/beta catenin signaling seem to be deeply involved in the pathogenesis of bone alterations and atherosclerotic processes also affect arteries of the lower extremities. Hypovitaminosis D could also play a role in the relationship of these two diseases. New and larger studies are necessary to shed light on this association and to design new drugs able to act in both these chronic degenerative diseases.

Association of bone metabolism markers with coronary atherosclerosis and coronary artery disease in postmenopausal women

This study aimed to evaluate the association of bone metabolism markers with coronary atherosclerosis and coronary artery disease (CAD) in postmenopausal women. Based on the findings of coronary angiography, 111 women with CAD and 116 women without CAD were recruited. Serum calcium, phosphate, parathyroid hormone (PTH), 25-hydroxyvitamin D (25OHD), osteocalcin, N-terminal propeptide of type I procollagen (P1NP) and C-terminal cross-linked telopeptide of type I collagen (CTX) were measured. The Gensini score was used to assess the severity of coronary atherosclerosis. Compared with women with serum calcium ≤2.29 mmol/L, women with serum calcium >2.29 mmol/L had a 2.63-fold increased risk of CAD after adjusting for multiple cardiovascular risks, PTH and 25OHD [odds ratio (OR) = 2.91, 95% confidence interval (CI) 1.35-6.28]. In the fully adjusted model plus PTH and 25OHD, the risk of CAD increased 1.87-fold with every 1-SD increment of serum calcium (OR = 1.87, 95% CI 1.21-2.88). To further analyze the potential strong confounding effect of albumin, the absolute levels of calcium were replaced by their albumin-corrected values in the regression model. Compared with women with albumin-corrected calcium ≤2.27 mmol/L, women with albumin-corrected calcium >2.27 mmol/L had a 2.36-fold increased risk of CAD in the fully adjusted model plus PTH and 25OHD (OR = 2.36, 95% CI 1.13-4.92). The risk of coronary atherosclerosis as defined by Gensini score >0 increased 1.73-fold with every 1-SD increment of serum calcium in the fully adjusted model plus PTH and 25OHD (OR = 1.73, 95% CI 1.09-2.73). However, albumin-corrected calcium was not associated with coronary atherosclerosis either as a categorical variable or as a continuous variable in all models. No significant association of PTH, 25OHD, osteocalcin, CTX and P1NP with CAD or coronary atherosclerosis was found in this study. Higher serum calcium levels were independently associated with CAD in postmenopausal women.

Is Sclerostin Level Associated with Cardiovascular Diseases in Hemodialysis Patients?

BACKGROUND/AIMS

The objective of this study is to evaluate the relation between sclerostin, arterial stiffness, and cardiovascular events (CVE) in hemodialysis patients (HD).

METHODS

Sclerostin level and carotid-femoral pulse wave velocity (PWV) in 97 HD patients and sclerostin level in 40 controls were measured.

RESULTS

Sclerostin level was significantly higher in patients than in controls. Sclerostin associated positively with age, male gender, cardiovascular disease, statin use, BMI, and PWV while negatively with alkaline phosphatase, parathormone (PTH), Kt/V, cinacalcet and vitamin D use in univariable correlation analyses. Sclerostin associated positively with male gender and statin use but negatively with PTH in multivariate regression analyses. During observation, 30 fatal or nonfatal CVEs were observed. While univariate correlation analysis showed a positive association between PWV and sclerostin, there was no relation between the two in multivariate regression analysis.

CONCLUSION

Further studies are needed to understand the role of sclerostin in predicting PWV changes in HD patients.

Multifaceted interaction of bone, muscle, lifestyle interventions and metabolic and cardiovascular disease: role of osteocalcin

Undercarboxylated osteocalcin (ucOC) may play a role in glucose homeostasis and cardiometabolic health. This review examines the epidemiological and interventional evidence associating osteocalcin (OC) and ucOC with metabolic risk and cardiovascular disease. The complexity in assessing such correlations, due to the observational nature of human studies, is discussed. Several studies have reported that higher levels of ucOC and OC are correlated with lower fat mass and HbA1c. In addition, improved measures of glycaemic control via pharmacological and non-pharmacological (e.g. exercise or diet) interventions are often associated with increased circulating levels of OC and/or ucOC. There is also a relationship between lower circulating OC and ucOC and increased measures of vascular calcification and cardiovascular disease. However, not all studies have reported such relationship, some with contradictory findings. Equivocal findings may arise because of the observational nature of the studies and the inability to directly assess the relationship between OC and ucOC on glycaemic control and cardiovascular health in humans. Studying OC and ucOC in humans is further complicated due to numerous confounding factors such as sex differences, menopausal status, vitamin K status, physical activity level, body mass index, insulin sensitivity (normal/insulin resistance/T2DM), tissue-specific effects and renal function among others. Current observational and indirect interventional evidence appears to support a relationship between ucOC with metabolic and cardiovascular disease. There is also emerging evidence to suggest a direct role of ucOC in human metabolism. Further mechanistic studies are required to (a) clarify causality, (b) explore mechanisms involved and

Joint Association of Low Vitamin D and Vitamin K Status With Blood Pressure and Hypertension

Low vitamin D and K status are both associated with an increased cardiovascular risk. New evidence from experimental studies on bone health suggest an interaction between vitamin D and K; however, a joint association with vascular health outcomes is largely unknown. To prospectively investigate whether the combination of low vitamin D and K status is associated with higher systolic and diastolic blood pressure in 402 participants and with incident hypertension in 231 participants free of hypertension at baseline. We used data from a subsample of the Longitudinal Aging Study Amsterdam, a population-based cohort of Dutch participants aged 55 to 65 years. Vitamin D and K status were assessed by 25-hydroxyvitamin D and dp-ucMGP (dephosphorylated uncarboxylated matrix gla protein) concentrations (high dp-ucMGP is indicative for low vitamin K status) in stored samples from 2002 to 2003. Vitamin D and K status were categorized into 25-hydroxyvitamin D <50/≥50 mmol/L and median dp-ucMGP <323/≥323 pmol/L. During a median follow-up of 6.4 years, 62% of the participants (n=143) developed hypertension. The combination of low vitamin D and K status was associated with increased systolic 4.8 mm Hg (95% confidence interval, 0.1–9.5) and diastolic 3.1 mm Hg (95% confidence interval, 0.5–5.7) blood pressure compared with high vitamin D and K status ( P for interaction =0.013 for systolic blood pressure and 0.068 for diastolic blood pressure). A similar trend was seen for incident hypertension: hazard ratio=1.62 (95% confidence interval, 0.96–2.73) for the low vitamin D and K group. The combination of low vitamin D and K status was associated with increased blood pressure and a trend for greater hypertension risk.

Sclerostin is a possible candidate marker of arterial stiffness: Results from a cohort study in Catania

Osteoporosis and cardiovascular disease are worldwide public health issues. Recent evidence indicates a possible role of the canonical Wnt/β-catenin signalling pathway as a common mediator between these two diseases. The aim of the present study was to investigate the relationship between serum concentrations of sclerostin and Dkk1, two extracellular inhibitors of Wnt/β-catenin signalling, with carotid intima-media thickness (CIMT) and with arterial stiffness, evaluated by measuring the pulse wave velocity (PWV) in an ambulatory population of adults. To this aim, 67 subjects were recruited in the 'Atherosclerosis and osteoporosis: identification of common pathogenetic factors' investigation. Serum sclerostin levels correlated positively with CIMT (r=0.314, p=0.03) and inversely with the augmentation index, a marker of arterial stiffness (r=-0.286, p<0.05), whereas Dkk1 did not. Moreover, in a multivariate linear regression model, sclerostin [β -0.1472; p=0.0023; standard error (SE)=0.04620] was an independent predictor of PWV in the study subjects. Our study shows that, following adjustment for confounders, sclerostin is an independent predictor of arterial stiffness in an ambulatory population, whereas Dkk1 is not.

Osteocalcin, Vascular Calcification, and Atherosclerosis: A Systematic Review and Meta-analysis

BACKGROUND

Osteocalcin (OC) is an intriguing hormone, concomitantly being the most abundant non-collagenous peptide found in the mineralized matrix of bone, and expanding the endocrine function of the skeleton with far-reaching extra-osseous effects. A new line of enquiry between OC and vascular calcification has emerged in response to observations that the mechanism of vascular calcification resembles that of bone mineralisation. To date, studies have reported mixed results. This systematic review and meta-analysis aimed to identify any association between OC and vascular calcification and atherosclerosis.

METHODS AND RESULTS

Databases were searched for original, peer reviewed human studies. A total of 1,453 articles were retrieved, of which 46 met the eligibility criteria. Overall 26 positive, 17 negative, and 29 neutral relationships were reported for assessments between OC (either concentration in blood, presence of OC-positive cells, or histological staining for OC) and extent of calcification or atherosclerosis. Studies that measured OC-positive cells or histological staining for OC reported positive relationships (11 studies). A higher percentage of Asian studies found a negative relationship (36%) in contrast to European studies (6%). Studies examining carboxylated and undercarboxylated forms of OC in the blood failed to report consistent results. The meta-analysis found no significant difference between OC concentration in the blood between patients with "atherosclerosis" and control (p = 0.13, n = 1,197).

CONCLUSION

No definitive association was determined between OC and vascular calcification or atherosclerosis; however, the presence of OC-positive cells and histological staining had a consistent positive correlation with calcification or atherosclerosis. The review highlighted several themes, which may influence OC within differing populations leading to inconclusive results. Large, longitudinal studies are required to further current understanding of the clinical relevance of OC in vascular calcification and atherosclerosis.

Treatment with cinacalcet increases plasma sclerostin concentration in hemodialysis patients with secondary hyperparathyroidism

Background

Sclerostin is a paracrine acting factor, which is expressed in the osteocytes and articular chondrocytes. Sclerostin decreases the osteoblast-related bone formation through the inhibition of the Wnt/β-catenin pathway. Osteocytes also express the Calcium sensing receptor which is a target for cinacalcet. The aim of this study was to assess the influence of six-month cinacalcet treatment on plasma sclerostin concentration in hemodialysed patients with secondary hyperparathyroidism (sHPT).

Methods

In 58 hemodialysed patients with sHPT (PTH > 300 pg/ml) plasma sclerostin and serum PTH, calcium and phosphate concentrations were assessed before the first dose of cinacalcet and after 3 and 6 months of treatment.

Results

Serum PTH concentration decreased after 3 and 6 month of treatment from 1138 (931–1345) pg/ml to 772 (551–992) pg/ml and to 635 (430–839) pg/ml, respectively. Mean serum calcium and phosphate concentrations remained stable. Plasma sclerostin concentration increased after 3 and 6 months of treatment from 1.66 (1.35–1.96) ng/ml, to 1.77 (1.43–2.12) ng/ml and to 1.87 (1.50–2.25) ng/ml, respectively. In 42 patients with cinacalcet induced serum PTH decrease plasma sclerostin concentration increased after 3 and 6 months of treatment from 1.51 (1.19–1.84) ng/ml to 1.59 (1.29–1.89) ng/ml and to 1.75 (1.42–2.01) ng/ml, respectively. Contrary, in the 16 patients without cinacalcet induced serum PTH decrease plasma sclerostin concentration was stable. Plasma sclerostin concentrations correlated inversely with serum PTH concentrations at the baseline and also after 6 months of treatment.

Conclusions

1. In hemodialysed patients with secondary hyperparathyroidism treatment with cinacalcet increases plasma sclerostin concentration 2. This effect seems to be related to decrease of serum PTH concentration.

Sclerostin Expression in Bile Ducts of Patients With Chronic Cholestasis May Influence the Bone Disease in Primary Biliary Cirrhosis

Sclerostin is involved in the regulation of osteoblastogenesis and little is known about its role in the development of bone disease in primary biliary cirrhosis (PBC), characterized by low bone formation. Therefore, we have assessed the circulating levels and the liver expression of sclerostin in this cholestatic disease. Serum sclerostin levels were measured in 79 women with PBC (mean age 60.6 ± 1.2 years) and in 80 control women. Lumbar and femoral bone mineral density (BMD), as well as parameters of mineral metabolism and bone remodeling, were measured. Moreover, sclerostin gene (SOST) expression in the liver was assessed by real-time PCR in samples of liver tissue taken by biopsy in 11 PBC patients and in 5 normal liver specimens. Presence and distribution of sclerostin was evaluated in liver slices from 11 patients by immunohistochemistry. The severity of histologic lesions was assessed semiquantitatively in the same liver samples. PBC patients had higher sclerostin levels than controls (75.6 ± 3.9 versus 31.7 ± 1.6 pmol/L, p < 0.001). Serum sclerostin correlated inversely with markers of bone formation and resorption. Sclerostin mRNA in the liver was overexpressed compared with control samples (2.7-fold versus healthy liver). Sclerostin was detected by immunohistochemistry in 7 of the 11 liver samples, mainly located in the bile ducts. Liver sclerostin was associated with the severity of cholangitis (p = 0.02) and indirectly with the degree of lobular inflammation (p = 0.03). Sclerostin mRNA expression was higher in samples that tested positive by immunohistochemistry and particularly in those with lobular granuloma (p = 0.02). The increased expression of sclerostin in the liver and the association with histologic cholangitis may explain the high serum levels of this protein in patients with PBC, thus suggesting that sclerostin may influence the decreased bone formation in this cholestatic disease. © 2016 American Society for Bone and Mineral Research.

High serum levels of sclerostin and Dickkopf-1 are associated with acute ischaemic stroke

BACKGROUND AND AIMS

Sclerostin and Dickkopf-1 (Dkk-1) are potent antagonists of Wnt signalling and might therefore play important roles in cardiovascular disease. We investigated whether serum sclerostin and Dkk-1 levels are associated with acute ischaemic stroke and specific stroke subtypes.

METHODS

Serum levels of sclerostin and Dkk-1 were measured by ELISA on day 1 and on day 6 after stroke in 62 patients with large artery atherosclerotic (LAA) stroke, on day 1 after stroke in 62 age- and gender-matched patients with small-artery occlusion (SAO) stroke and on admission in 62 healthy controls. Stroke severity was determined based on the National Institutes of Health Stroke Scale (NIHSS) and by measuring stroke volume on diffusion-weighted imaging. Outcome was measured by the modified Rankin Scale (mRS) on day 90.

RESULTS

Compared with controls, serum sclerostin and Dkk-1 levels were significantly higher in both patients with LAA stroke and with SAO stroke, and no difference was detected between the stroke subtypes. Sclerostin and Dkk-1 levels remained stable between the first and sixth day after stroke in the patients with LAA stroke. Receiver operating characteristic curve analysis was used to evaluate sclerostin and Dkk-1 as markers of a high risk of stroke and produced area under curve values of 0.773 and 0.776. Adjusted logistic regression showed that serum sclerostin and Dkk-1 levels remained as independent markers of stroke. No correlations were found between sclerostin or Dkk-1 levels and stroke severity or stroke outcome.

CONCLUSIONS

High serum levels of sclerostin and Dkk-1 are associated with acute ischaemic stroke.

The mechanisms underlying the beneficial effects of exercise on bone remodeling: Roles of bone-derived cytokines and microRNAs

Bone remodeling is highly dynamic and complex in response to mechanical loading, such as exercise. In this review, we concluded that a number of individual factors are disturbing the clinical effects of exercise on bone remodeling. We updated the progress made on the differentiation of osteoblasts and osteoclasts in response to mechanical loading, hoping to provide a theoretical basis to improve bone metabolism with exercise. Increasing evidences indicate that bone is not only a structural scaffold but also an endocrine organ, which secretes osteocalcin and FGF23. Both of them have been known as a circulating hormone to promote insulin sensitivity and reduce body fat mass. The effects of exercise on these bone-derived cytokines provide a better understanding of how exercise-induced "osteokine" affects the whole-body homeostasis. Additionally, we discussed recent studies highlighting the post-transcriptional regulation of microRNAs in bone remodeling. We focus on the involvement of the microRNAs in osteoblastogenesis and osteoclastogenesis, and suggest that microRNAs may be critical for exercise-induced bone remodeling.