Plasma Osteoprotegerin Levels in the General Population

Osteoprotegerin as an Emerging Biomarker of Carotid Artery Stenosis? A Scoping Review with Meta-Analysis

Objective: In developed countries, stroke is the fifth cause of death, with a high mortality rate, and with recovery to normal neurological function in one-third of survivors. Atherosclerotic occlusive disease of the extracranial part of the internal carotid artery and related embolic complications are common preventable causes of ischemic stroke (IS), attributable to 7-18% of all first-time cases. Osteoprotegerin (OPG), a soluble member of the tumor necrosis factor receptor (TNFR) superfamily, is considered a modulator of vascular calcification linked to vascular smooth muscle cell proliferation and collagen production in atherosclerotic plaques. Therefore, OPG emerges as a potential biomarker (BM) of calcified carotid plaques and carotid artery stenosis (CAS). Methods: We performed a literature search of PubMed on OPG in CAS and atherosclerosis published until 2024. Results: Increased levels of serum OPG were reported in both patients with symptomatic and asymptomatic CAS, and higher values were observed in those with unstable atherosclerotic plaques. Notably, increased OPG levels were observed regardless of the location of atherosclerosis, including coronary and other peripheral arteries. In addition, chronic kidney disease, the most significant confounder disturbing the association between vascular damage and circulating OPG levels, decreases the usefulness of OPG as a BM in CAS. Conclusions: Osteoprotegerin may be considered an emerging BM of global rather than cerebrovascular atherosclerosis. Its diagnostic significance in identifying patients with asymptomatic CAS and their monitoring is limited.

Osteoprotegerin is associated with subclinical left ventricular systolic dysfunction in non-dipper hypertensive patients: a 2D speckle tracking echocardiographic study

BACKGROUND

Past studies have shown that non-dipper hypertensive patients have more frequent subclinical left ventricular (LV) systolic dysfunction compared to dippers. Many different parameters have been examined to predict subclinical LV dysfunction. The role of osteoprotegerin (OPG) in the pathogenesis of heart failure and LV systolic dysfunction through different mechanisms had well described. In the present study, we hypothesized that increased OPG levels could predict subclinical LV systolic dysfunction in non-dipper hypertensive patients.

PATIENTS AND METHODS

Hypertensive patients were divided into two groups according to the results of ambulatory blood pressure (BP) monitoring. Non-dipper patients were subsequently divided into two further groups (normal LV function and impaired LV function) according to LV global longitudinal strain (GLS).

RESULTS

A total of 103 hypertensive patients (51 dippers, 52 non-dippers) were included in the study. In the non-dipper group, LV GLS was normal in 21 patients and impaired in 31 patients. Based on the results of the multivariate logistic regression test, it was determined that OPG levels (OR: 2.413, 95% CI: 1.284-4.535, P  = 0.006) and LVMI (OR: 1.086, 95% CI: 1.013-1.165, P  = 0.021) were independently associated with impaired GLS.

CONCLUSION

Higher OPG values were associated with subclinical LV systolic dysfunction in non-dipper hypertensive patients. It could be used for the early diagnosis of subclinical LV systolic dysfunction, which would allow for strategies to be designed to reduce the cardiovascular event rate in this patient population.

Plasma osteoprotegerin predicts adverse cardiovascular events in stable coronary artery disease: the PEACE trial

Background

Osteoprotegerin (OPG) is a secretory glycoprotein and participates in the progression of atherosclerotic lesions. We aim to explore the relationship between OPG and the prognosis of coronary artery disease (CAD).

Methods

Plasma OPG concentrations were measured in 3,766 patients with stable CAD enrolled in the PEACE trial. The PEACE trial (NCT00000558) group followed up the patients and examined their future clinical outcomes.

Results

In summary, 208 (5.5%) primary outcomes occurred, 295 patients (7.8%) died from all-cause death, 128 (3.4%) died from cardiovascular causes, and 94 (2.5%) experienced heart failure during a median follow-up of 1,892 days. In addition, we found that higher plasma levels of OPG were associated with a higher incidence of all-cause death, cardiovascular death, and heart failure, even after adjusting clinical cofounders.

Conclusion

It was demonstrated that elevated plasma OPG levels were associated with an increased incidence of all-cause death, cardiovascular death, and heart failure in patients with stable CAD.

Systematic Review Registration

https://clinicaltrials.gov/ct2/show/NCT00000558?term=NCT00000558&draw=2&rank=1, identifier: NCT00000558.

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.

Advances in congestive heart failure biomarkers

Congestive heart failure (CHF) is the leading cause of morbidity and mortality in the elderly worldwide. Although many biomarkers associated with in heart failure, these are generally prognostic and identify patients with moderate and severe disease. Unfortunately, the role of biomarkers in decision making for early and advanced heart failure remains largely unexplored. Previous studies suggest the natriuretic peptides have the potential to improve the diagnosis of heart failure, but they still have significant limitations related to cut-off values. Although some promising cardiac biomarkers have emerged, comprehensive data from large cohort studies is lacking. The utility of multiple biomarkers that reflect various pathophysiologic pathways are increasingly being explored in heart failure risk stratification and to diagnose disease conditions promptly and accurately. MicroRNAs serve as mediators and/or regulators of renin-angiotensin-induced cardiac remodeling by directly targeting enzymes, receptors and signaling molecules. The role of miRNA in HF diagnosis is a promising area of research and further exploration may offer both diagnostic and prognostic applications and phenotype-specific targets. In this review, we provide insight into the classification of different biochemical and molecular markers associated with CHF, examine clinical usefulness in CHF and highlight the most clinically relevant.

Osteoporosis Entwined with Cardiovascular Disease: The Implication of Osteoprotegerin and the Example of Statins

Beyond being epiphenomenon of shared epidemiological factors, the integration of Osteoporosis (OP) with Cardiovascular Disease (CVD) - termed "calcification paradox" - reflects a continuum of aberrant cardiometabolic status. The present review provides background knowledge on "calcification paradox", focusing on the endocrine aspect of vasculature orchestrated by the osteoblastic molecular fingerprint of vascular cells, acquired via imbalance among established modulators of mineralization. Osteoprotegerin (OPG), the well-established osteoprotective cytokine, has recently been shown to exert a vessel-modifying role. Prompted by this notion, the present review interrogates OPG as the potential missing link between OP and CVD. However, so far, the confirmation of this hypothesis is hindered by the equivocal role of OPG in CVD, being both proatherosclerotic and antiatherosclerotic. Further research is needed to illuminate whether OPG could be a biomarker of the "calcification paradox". Moreover, the present review brings into prominence the dual role of statins - cardioprotective and osteoprotective - as a potential illustration of the integration of CVD with OP. Considering that the statins-induced modulation of OPG is central to the statins-driven osteoprotective signalling, statins could be suggested as an illustration of the role of OPG in the bone/vessels crosstalk, if further studies consolidate the contribution of OPG to the cardioprotective role of statins. Another outstanding issue that merits further evaluation is the inconsistency of the osteoprotective role of statins. Further understanding of the varying bone-modifying role of statins, likely attributed to the unique profile of different classes of statins defined by distinct physicochemical characteristics, may yield tangible benefits for treating simultaneously OP and CVD.

Serum Osteoprotegerin and Carotid Intima-Media Thickness Are Related to High Arterial Stiffness in Heart Failure with Reduced Ejection Fraction

Arterial stiffness (AS) is a complex vascular phenomenon with consequences for central hemodynamics and left-ventricular performance. Circulating biomarkers have been associated with AS; however, their value in heart failure is poorly characterized. Our aim was to evaluate the clinical and biomarker correlates of AS in the setting of heart failure with reduced ejection fraction (HFrEF). In 78 hospitalized, hemodynamically stable patients (20 women, 58 men, mean age 65.8 ± 1.41 years) with HFrEF, AS was measured using aortic pulse wave velocity (PWV). Serum OPG, RANKL, sclerostin, and DKK-1 were determined, and the relationships between the clinical variables, vascular-calcification-related biomarkers, and PWV were evaluated by correlation analysis and linear and logistic regression models. OPG and the OPG/RANKL ratio were significantly higher in the group of patients (n = 37, 47.4%) with increased PWV (>10 m/s). PWV was positively correlated with age, left-ventricular ejection fraction, and carotid intima-media thickness (cIMT), and negatively correlated with the glomerular filtration rate. OPG and cIMT were significantly associated with PWV in the logistic regression models when adjusted for hypertension, EF, and the presence of atherosclerotic manifestations. Elevated serum OPG, together with cIMT, were significantly related to increased AS in the setting of HFrEF.

Osteoprotegerin is a marker of cardiovascular mortality in patients with chronic kidney disease stages 3-5

Cardiovascular disease (CVD) is the leading cause of death in patients with chronic kidney disease (CKD). Osteoprotegerin (OPG), known to regulate bone mass by inhibiting osteoclast differentiation and activation, might also play a role in vascular calcification. Increased circulating OPG levels in patients with CKD are associated with aortic calcification and increased mortality. We assessed the predictive role of OPG for all-cause and cardiovascular mortality in patients with CKD stages 3-5 over a 5-year follow-up period. We evaluated the relationship between OPG and all-cause and cardiovascular mortality in 145 CKD patients (stages 3-5) in a prospective observational follow-up study. Inflammation markers, including high-sensitivity C-reactive protein, standard echocardiography, and estimation of intima-media thickness in the common carotid artery, were assessed at baseline, and correlations with OPG levels were determined. The cutoff values for OPG were defined using ROC curves for cardiovascular mortality. Survival was assessed during follow up lasting for up to 5.5 years using Fine and Gray model. A total of 145 (89 men; age 58.9 ± 15.0 years) were followed up. The cutoff value for OPG determined using ROC was 10 pmol/L for general causes mortality and 10.08 pmol/L for CV causes mortality. Patients with higher serum OPG levels presented with higher mortality rates compared to patients with lower levels. Aalen-Johansen cumulative incidence curve analysis demonstrated significantly worse survival rates in individuals with higher baseline OPG levels for all-cause and cardiovascular mortality (p < 0.001). In multivariate analysis, OPG was a marker of general and cardiovascular mortality independent of sex, age, CVD, diabetes, and CRP levels. When CKD stages were included in the multivariate analysis, OPG was an independent marker of all-cause mortality but not cardiovascular mortality. Elevated serum OPG levels were associated with higher all-cause and cardiovascular mortality risk, independent of age, CVD, diabetes, and inflammatory markers, in patients with CKD.

The role of osteoprotegerin in the development, progression and management of abdominal aortic aneurysms

Osteoprotegerin (OPG) appears to be a very promising marker both in the diagnosis of abdominal aortic aneurysms (AAAs) and as a potential target in its treatment. This article presents an overview of the current literature that discusses the role of OPG in the pathogenesis of atherosclerosis and its potential value as a prognostic factor in AAA. Pharmacological modulation of OPG expression has been considered. In conclusion, it seems that further research designed to assess the relationship between OPG and AAA is needed as this may contribute to improved AAA monitoring and more effective treatment of patients with AAA.

Racial Differences in Cardiovascular Biomarkers in the General Population

Background

The incidence and clinical manifestations of cardiovascular disease (CVD) differ between blacks and whites. Biomarkers that reflect important pathophysiological pathways may provide a window to allow deeper understanding of racial differences in CVD.

Methods and Results

The study included 2635 white and black participants from the Dallas Heart Study who were free from existing CVD. Cross‐sectional associations between race and 32 biomarkers were evaluated using multivariable linear regression adjusting for age, traditional CVD risk factors, imaging measures of body composition, renal function, insulin resistance, left ventricular mass, and socioeconomic factors. In fully adjusted models, black women had higher lipoprotein(a), leptin, d‐dimer, osteoprotegerin, antinuclear antibody, homoarginine, suppression of tumorigenicity‐2, and urinary microalbumin, and lower adiponectin, soluble receptor for advanced glycation end products and N‐terminal pro‐B‐type natriuretic peptide versus white women. Black men had higher lipoprotein(a), leptin, d‐dimer, high‐sensitivity C‐reactive protein, antinuclear antibody, symmetrical dimethylarginine, homoarginine, high‐sensitivity cardiac troponin T, suppression of tumorigenicity‐2, and lower adiponectin, soluble receptor for advanced glycation end products, and N‐terminal pro‐B‐type natriuretic peptide versus white men. Adjustment for biomarkers that were associated with higher CVD risk, and that differed between blacks and whites, attenuated the risk for CVD events in black women (unadjusted hazard ratio 2.05, 95% CI 1.32, 3.17 and adjusted hazard ratio 1.15, 95% CI 0.69, 1.92) and black men (unadjusted hazard ratio 2.39, 95% CI 1.64, 3.46, and adjusted hazard ratio 1.21, 95% CI 0.76, 1.95).

Conclusions

Significant racial differences were seen in biomarkers reflecting lipids, adipokines, and biomarkers of endothelial function, inflammation, myocyte injury, and neurohormonal stress, which may contribute to racial differences in the development and complications of CVD.

See Editorial Suzuki et al

[Osteoprotegerin is a new marker of cardiovascular diseases]

Osteoprotegerin (OPG) is a glycoprotein that is a representative of the tumor necrosis factor-α receptor superfamily. Information about the possible role of OPG in the development of cardiovascular diseases has begun to appear in the literature in recent years. This review discusses the role of increasing the level of OPG in the development and progression of atherosclerosis and as a consequence of coronary heart disease and chronic heart failure.

Association of OPG-RANKL ratio with left ventricular hypertrophy and geometric remodeling in male overweight/obese youths

PURPOSE

Receptor activator of nuclear factor kappa B ligand/receptor activator of nuclear factor kappa B/osteoprotegerin (RANKL/RANK/OPG) axis has been hypothesized as a potential mediator of left ventricular hypertrophy (LVH). The aim of the study was to assess whether circulating concentrations of RANKL, RANK, and OPG were associated with early signs of morphological cardiac changes in overweight/obese youths.

METHODS

We determined serum levels of RANKL, RANK and OPG by enzyme-linked immunosorbent assays in 188 overweight/obese children and adolescents. LV mass index (LVMI) and relative wall thickness (RWT) were estimated using M-mode echocardiography.

RESULTS

OPG and RANKL levels were higher among girls than among boys [1.73 (1.64-1.86) and 3.28 (1.90-6.37) pmol/L, respectively, vs. 1.69 (1.59-1.82) and 2.12 (1.52-3.80) pmol/L; p = 0.02 and p = 0.0001, respectively], but the OPG/RANKL ratio was lower [0.52 (0.26-0.88) vs 0.77 (0.44-1.11); p = 0.001]. In gender-specific multivariate linear regression, OPG/RANKL ratio was associated with LVMI and RWT in boys but not in girls. In multiple logistic regression, after adjustment for clinical variables, OPG/RANKL ratio was associated with concentric remodeling, eccentric and concentric LVH in boys but not in girls.

CONCLUSION

OPG/RANKL ratio is independently associated with LVH and patterns of LV structural remodeling in male overweight/obese children and adolescents.

Plasma RANKL levels are not associated with breast cancer risk in BRCA1 and BRCA2 mutation carriers

Background

Aberrant progesterone/receptor activator of nuclear factor κβ (RANK) signaling has been implicated in BRCA1 breast cancer development. Furthermore, lower circulating RANKL has been reported among women with a BRCA mutation compared to non-carriers; however, there have been no reports of plasma RANKL levels and subsequent breast cancer risk. We prospectively evaluated the relationship between plasma RANKL and breast cancer risk among women with a BRCA1 or BRCA2 mutation.

Methods

An enzyme-linked immunosorbent assay was used to quantify plasma RANKL levels in 184 BRCA mutation carriers. Women were stratified into high vs. low RANKL based on the median levels of the cohort (5.24 pg/ml). Kaplan-Meier survival analysis was used to estimate the cumulative incidence of breast cancer by baseline plasma RANKL and cox proportional hazards models were used to estimate the adjusted hazard ratios (HRs) and 95% confidence intervals (CI) for the association between plasma RANKL and risk.

Results

Over a mean follow-up of 6.3 years (0.02-19.24), 15 incident breast cancers were identified. The eight-year cumulative incidence was 10% in the low RANKL group and 12% in the high RANKL group (P-log-rank = 0.85). There was no significant association between plasma RANKL levels and breast cancer risk (multivariate HR high vs. low = 1.06; 95%CI 0.34-3.28; P-trend = 0.86).

Conclusions

These findings suggest that circulating RANKL levels are not associated with breast cancer among BRCA mutation carriers. Pending validation in a larger sample, these findings suggest that RANKL is likely not a biomarker of breast cancer risk among BRCA mutation carriers.

Elevated serum osteoprotegerin is associated with increased left ventricular mass index and myocardial stiffness

AIM

Osteoprotegerin (OPG) is associated with a poor prognosis in patients with heart failure with preserved ejection fraction (HFpEF). OPG has also been associated with fibrosis and collagen cross-linking, which increase arterial and left ventricle (LV) myocardial stiffness. Little is known about the relation of OPG and LV structure and function in African-Americans who are disproportionately affected by HFpEF.

METHODS AND RESULTS

Our analysis included 1172 participants with preserved LV ejection fraction (>50%) from the African-American cohort in the Genetic Epidemiology Network of Arteriopathy Study (mean age 63 years, 72% female). We used diastolic wall strain indicator measured by echocardiography to assess LV myocardial stiffness. Diastolic wall strain was calculated as (LV posterior thickness at end-systole - LV posterior thickness at end-diastole)/LV posterior thickness at end-systole. Associations between OPG levels and indices of arterial and LV structure and function were evaluated by using generalized linear mixed models and adjusted for possible confounders. OPG levels were correlated with age, female sex, presence of hypertension and diabetes, and lower estimated glomerular filtration rate (P < 0.05 for all). Multivariable analysis revealed that higher OPG levels were associated with greater LV mass index, increased LV myocardial stiffness, and higher N-terminal prohormone brain natriuretic peptide levels (P < 0.05 for all).

CONCLUSION

In African-Americans, higher OPG levels were associated with characteristics common in patients with HFpEF and were significantly associated with known precursors to HFpEF. These findings indicate a potential role for OPG in the pathophysiology of HFpEF in African-Americans.

Role of osteoprotegerin/receptor activator of nuclear factor kappa B/receptor activator of nuclear factor kappa B ligand axis in nonalcoholic fatty liver disease

Concomitantly with the increase in the prevalences of overweight/obesity, nonalcoholic fatty liver disease (NAFLD) has worldwide become the main cause of chronic liver disease in both adults and children. Patients with fatty liver display features of metabolic syndrome (MetS), like insulin resistance (IR), glucose intolerance, hypertension and dyslipidemia. Recently, epidemiological studies have linked obesity, MetS, and NAFLD to decreased bone mineral density and osteoporosis, highlighting an intricate interplay among bone, adipose tissue, and liver. Osteoprotegerin (OPG), an important symbol of the receptor activator of nuclear factor-B ligand/receptor activator of nuclear factor kappa B/OPG system activation, typically considered for its role in bone metabolism, may also play critical roles in the initiation and perpetuation of obesity-related comorbidities. Clinical data have indicated that OPG concentrations are associated with hypertension, left ventricular hypertrophy, vascular calcification, endothelial dysfunction, and severity of liver damage in chronic hepatitis C. Nonetheless, the relationship between circulating OPG and IR as a key feature of MetS as well as between OPG and NAFLD remains uncertain. Thus, the aims of the present review are to provide the existent knowledge on these associations and to discuss briefly the underlying mechanisms linking OPG and NAFLD.

The Role of Osteoprotegerin as a Cardioprotective Versus Reactive Inflammatory Marker: the Chicken or the Egg Paradox

Cardiovascular disease is one of the most frequent causes of mortality and morbidity worldwide. Several variables have been identified as risk factors for cardiovascular disease. Recently, the role of receptor activator of nuclear factor kappa B, receptor activator of nuclear factor kappa B ligand, and the osteoprotegerin system has been recognized as more important in the pathogenesis of cardiovascular disease. Besides their roles in the regulation of bone resorption, these molecules have been reported to be associated with the pathophysiology of cardiovascular disease. There are conflicting data regarding the impact of osteoprotegerin, a glycoprotein with a regulatory role in the cardiovascular system. The aim of this review is to discuss the current knowledge and the role of osteoprotegerin in cardiovascular disease.

Osteoprotegerin concentration and risk of cardiovascular outcomes in nine general population studies: Literature-based meta-analysis involving 26,442 participants

Background

Recent experimental and epidemiological studies have suggested that osteoprotegerin, a key regulator in bone metabolism, may be involved in vascular calcification and atherosclerosis. Our aim was to reliably quantify the associations of osteoprotegerin concentration and incidence of first-ever cardiovascular disease outcomes in the general population.

Methods

Using the electronic databases MEDLINE, EMBASE and Web of Science (January 1975 and April 2017, no language restrictions), nine relevant studies were identified involving a total of 26,442 participants recruited from the general population. Over a mean follow-up of 8.5 years, 2,160 cardiovascular disease, 2,123 coronary heart disease, and 1,102 stroke outcomes were recorded. Study-specific risk ratios were combined with random-effects meta-analysis.

Results

When comparing individuals in the top with those in the bottom third of osteoprotegerin concentration, the combined risk ratio was 1.83 (95% confidence interval: 1.46, 2.30; P<0.001; I² = 76.8%) for cardiovascular disease, 1.72 for coronary heart disease (1.26, 2.37; P = 0.001; I² = 83.5%), and 1.58 for stroke (1.18, 2.12; P = 0.002; I² = 65.2%). Associations appeared stronger at younger age (P = 0.018 for cardiovascular disease), in studies that did not employ statistical adjustment (P = 0.023 for cardiovascular disease and 0.018 for coronary heart disease), and potentially in studies that measured osteoprotegerin in plasma rather than in serum (P = 0.005 for cardiovascular disease and 0.018 for coronary heart disease). Magnitudes of associations did not differ according to the proportion of males, geographical region, or osteoprotegerin assay manufacturer. There was no evidence for publication bias for any of the outcomes assessed (all P>0.05).

Conclusions

Elevated osteoprotegerin concentration is associated with an increased risk of incident cardiovascular disease in the general population. The mechanisms underlying this observation deserve further investigation.

Distribution of alkaline phosphatase, osteopontin, RANK ligand and osteoprotegerin in calcified human carotid atheroma

Ectopic vascular calcification is a significant component of atherosclerotic disease. Osteopontin (OPN), Osteoprotegerin (OPG), Receptor Activator of NFκB Ligand (RANKL), and alkaline phosphatase (ALP) are each thought to play central roles in the calcification or demineralization of atherosclerotic lesions. Abnormalities in the balance of these proteins may lead to perturbations in bone remodeling and arterial calcification. The purpose of this study was to measure the distribution of these proteins in human carotid lesions and to elucidate possible mechanism(s) whereby they control the deposition or depletion of arterial calcification. Thirty-three patients who had undergone carotid endarterectomy (CEA) within the previous 18 months and 11 control patients were enrolled. CEA specimens were analyzed by EBCT for calcification content in terms of Agatston (AGAT) and Volume scores. CEA specimens were then cut into 5 mm segments which were homogenized and extracted. Extracts were analyzed for tissue levels of calcium, phosphorus, ALP, OPN, RANKL, and OPG. Fasting blood samples were analyzed for the same components. In CEA tissue segments, the calcification levels (CHA AGAT) were inversely associated with the levels of OPG (r = -0.432/-0.579, p < 0.05) and positively associated with the levels of RANKL (r = 0.332/0.415, p < 0.05). In turn, the tissue levels of OPG were associated with homologous serum levels of OPG (r = 0.820/0.389, p < 0.001), and the tissue levels of RANKL were associated with the serum levels of homologous RANKL (r = 0.739/0.666, p < 0.0001). This study suggests that serum levels of OPG and RANKL may be useful biomarkers for estimating the degree of calcification in carotid atherosclerotic lesions.

Angiotensin II Stimulation of Cardiac Hypertrophy and Functional Decompensation in Osteoprotegerin-Deficient Mice

Circulating and myocardial expressions of receptor activator of nuclear factor-κb ligand and osteoprotegerin are activated in heart failure; however, it remains to be determined their pathophysiological roles on left ventricular structure and function in interaction with renin-angiotensin system. We conducted experiments using 8-week-old osteoprotegerin(-/-) mice and receptor activator of nuclear factor-κb ligand-transgenic mice to assess whether they affect the angiotensin II-induced left ventricular remodeling. Subcutaneous infusion of angiotensin II to osteoprotegerin(-/-) mice progressed the eccentric hypertrophy, resulting in left ventricular systolic dysfunction for 28 days, and this was comparable with wild-type mice, showing concentric hypertrophy, irrespective of equivalent elevation of systolic blood pressure. The structural alteration was associated with reduced interstitial fibrosis, decreased procollagen α1 and syndecan-1 expressions, and the increased number of apoptotic cells in the left ventricle, compared with wild-type mice. In contrast, angiotensin II infusion to the receptor activator of nuclear factor-κb ligand-transgenic mice revealed the concentric hypertrophy with preserved systolic contractile function. Intraperitoneal administration of human recombinant osteoprotegerin, but not subcutaneous injection of anti-receptor activator of nuclear factor-κb ligand antibody, to the angiotensin II-infused osteoprotegerin(-/-) mice for 28 days ameliorated the progression of heart failure without affecting systolic blood pressure. These results underscore the biological activity of osteoprotegerin in preserving myocardial structure and function during the angiotensin II-induced cardiac hypertrophy, independent of receptor activator of nuclear factor-κb ligand activity. In addition, the antiapoptotic and profibrotic actions of osteoprotegerin that emerged from our data might be involved in the mechanisms.

Amlodipine and atorvastatin improved hypertensive cardiac hypertrophy through regulation of receptor activator of nuclear factor kappa B ligand/receptor activator of nuclear factor kappa B/osteoprotegerin system in spontaneous hypertension rats

The present study aims to study the role of receptor activator of nuclear factor kappa B ligand/receptor activator of nuclear factor kappa B/osteoprotegerin (RANKL/RANK/OPG) system in cardiac hypertrophy in a spontaneous hypertension rat (SHR) model and the effects of amlodipine and atorvastatin intervention. Thirty-six-week-old male SHRs were randomly divided into four groups: 1) SHR control group; 2) amlodipine alone (10 mg/kg/d) group, 3) atorvastatin alone (10 mg/kg/d) group, 4) combination of amlodinpine and atorvastatin (10 mg/kg/d for each) group. Same gender, weight, and age of Wistar-Kyoto (WKY) rats with normal blood pressure were used as normal control. Drugs were administered by oral gavage over 12 weeks. The thicknesses of left ventricle walls, left ventricle weight, and cardiac function were measured by transthoracic echocardiography. Left ventricular pressure and function were assessed by hemodynamic examination. Cardiomyocyte hypertrophy and collagen accumulation in cardiac tissue were measured by hematoxylin and eosin (HE) and Masson staining, respectively. The hydroxyproline content of cardiac tissue was examined by biochemistry technique. RANKL, RANK and OPG mRNA, protein expression and tissue localization were studied by RT-PCR, Immunohistochemistry and Western blot. Treatment with amlodipine or atorvastatin alone significantly decreased left ventricular mass index, cardiomyocyte cross-sectional area and interstitial fibrosis in SHR (each P < 0.05). Moreover, combined amlodipine and atorvastatin treatment induced significant reversal of left ventricular hypertrophy and decreased cardiomyocyte cross-sectional area and interstitial fibrosis in SHR to a greater extent than each agent alone (P < 0.05). Compared with WKY rats, the myocardial expression of RANKL, RANK, and OPG was increased. Both amlodipine and atorvastatin reduced RANKL, RANK, and OPG expression, with the best effects seen with the combination. Based on our results, activation of the RANKL/RANK/OPG system may be an important factor leading to ventricular remodeling in SHR rats. Amlodipine and atorvastatin could improve ventricular remodeling in SHR rats through intervention with the RANKL/RANK/OPG system.

Markers of increased atherosclerotic risk in patients with chronic kidney disease: a preliminary study

BACKGROUND

The prevalence of chronic kidney disease is rising continuously. Cardiovascular disease is among leading causes of death and premature mortality of patients with chronic kidney disease. Even the earliest stages of chronic kidney disease are associated with higher risk of subsequent coronary heart disease. The aim of this study was to determine markers of increased risk of atherosclerosis in CKD.

METHODS

The study group consisted of a total of 80 patients (20 patients with stage I/II CKD, 20 with stage III CKD, 20 stage IV CKD and 20 stage V/dialysis) and 24 healthy volunteers. Levels of proteins (osteoprotegerin, osteopontin, osteocalcin, matrix γ-carboxyglutamic acid protein, fetuin A, MMP-2, MMP-9, TIMP-1, TIMP-2) and biochemical parameters were measured to analyse their influence on atherosclerosis risk in CKD patients. Cardiac echocardiography was performed to assess structural integrity and function, presence of left ventricular hypertrophy and systolic and diastolic function dysfunction.

RESULTS

This study shows that the prevalence of ventricular hypertrophy (95.3 %) and diastolic dysfunction (93.2 %) in CKD patients is high. Also E/E' ratio was significantly higher (13.6 ± 4.4, p = 0.001), tricuspid insufficiency (27.3 in CKD I/II vs. 71.4 in CKD V, p = 0.016), contractile dysfunction (33.3 in CKD I/II vs. 78.9 in CKD V, p = 0.040), mitral valve calcification (0 in CKD I/II vs. 28.6 in CKD V, p = 0.044) and aortic valve calcification (0 in CKD I/II vs. 61.9 in CKD V, p = 0.0008) were significantly more frequent in patients with CKD stage V/dialysis than in other groups. Only MMP-2, MMP-2/TIMP-2 ratio and TIMP-1 differed significantly between groups.

CONCLUSIONS

This study shows high prevalence of ventricular hypertrophy and diastolic dysfunction in CKD patients. Contractile dysfunction, mitral and aortic valve calcification in HD patients were significantly more frequent than in patients with other CKD stages. Significantly increased levels of MMP-2, MMP-2/TIMP-2 ratio and lower TIMP-1 suggests that these factors may be involved in the pathogenesis of atherosclerosis in CKD patients.

Cardiac hypertrophy is exacerbated in aged mice lacking the osteoprotegerin gene

AIMS

Osteoprotegerin (OPG) may play a role in the progression of cardiac hypertrophy and heart failure. However, its pathophysiological role in changes in cardiac structure and function with ageing remains to be elucidated.

METHODS AND RESULTS

We conducted experiments using 2.5- and 12-month-old OPG(-/-) mice and age-matched wild-type (WT) mice and compared the morphology and function of the left ventricle (LV). Both 2.5- and 12-month-old OPG(-/-) mice showed a higher systolic blood pressure and a greater heart weight/body weight ratio than age-matched WT mice. Twelve-month-old OPG(-/-) mice had a significantly larger LV chamber and reduced wall thickness compared with age-matched WT mice, and contractile function was decreased. The morphological differences were accompanied by an increase in the number of apoptotic cells and activation of tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) in the LV of 12-month-old OPG(-/-) mice. Correspondingly, OPG small interfering RNA induced the expressions of TRAIL and cleaved caspase-3 in cultured cardiac myocytes. In addition, these mice revealed a decrease in interstitial fibrosis, activation of matrix metalloproteinase (MMP)-2 and tissue inhibitors of MMP-1 and -2, and inactivation of procollagen α1 synthesis. Moreover, intraperitoneal administration of recombinant OPG to either 2.5- or 12-month-old OPG(-/-) mice for 28 days led to partial improvement of LV structure and function without affecting systolic blood pressure.

CONCLUSION

These results suggest that OPG plays a role in preserving myocardial structure and function with ageing through a reduction in apoptosis and preservation of the matrix structure. In addition, this appears to be independent of effects on the vasculature.

Relationship between osteoprotegerin and mortality in decompensated heart failure with preserved ejection fraction

AIM

The aim of this study was to evaluate whether osteoprotegerin - an emerging inflammatory biomarker in cardiovascular diseases - predicts outcomes in patients with acute heart failure and preserved ejection fraction.

METHODS

We measured urea, creatinine, hemoglobin, high-sensitivity C-reactive protein, N-terminal pro-B-type natriuretic peptide and osteoprotegerin on admission in 177 patients admitted with decompensated heart failure and left ventricular ejection fraction at least 45%. The population was divided according to the median values of osteoprotegerin (158.6 ng/l). Primary and secondary endpoints were all-cause mortality and death/readmission at 1-year follow-up, respectively. Multivariable Cox models were generated for osteoprotegerin and common risk factors. We also evaluated the reclassification of patients into risk categories after adding this biomarker to the model.

RESULTS

A total of 43 patients died during the follow-up and 84 had a combined event. Kaplan-Meier curves showed significantly increased primary and secondary endpoints according to the median of osteoprotegerin (log-rank, P < 0.0001 and 0.001, respectively). After adjustment for age, estimated glomerular filtration rate, hemoglobin, N-terminal pro-B-type natriuretic peptide, BMI and New York Heart Association III-IV, osteoprotegerin was a significant predictor of primary endpoint evaluated as continuous and categorized variable (relative risk 2.49, 95% confidence interval 1.18-5.24, P = 0.016 and relative risk 2.35, 95% confidence interval 1.11-4.96, P = 0.025, respectively). The clinical prediction model with osteoprotegerin evaluated with Net Reclassification Index was not significant.

CONCLUSION

Osteoprotegerin is independently associated with all-cause mortality in patients hospitalized for heart failure with preserved ejection fraction. However, adding this biomarker into a risk model does not improve its prediction value.

Role of osteoprotegerin and its gene polymorphisms in the occurrence of left ventricular hypertrophy in essential hypertensive patients

The aim of the study was to investigate the role of osteoprotegerin (OPG) in left ventricular hypertrophy (LVH) development in patients with essential hypertension (EH). A total of 1092 patients diagnosed with EH were recruited. The LVHs were determined and OPG gene polymorphisms were genotyped. Patients with LVH had a significantly higher mean serum OPG level than those without LVH. The 1181CC genotype carriers had significantly lower risk for LVH compared with GC and GG genotype carriers. The serum OPG level and OPG 1181 G>C polymorphism were found to be independent risk factors for the occurrence of LVH in hypertensive patients. In vitro study shows that OPG overexpression upregulates cell surface size, protein synthesis per cell, and hypertrophy- and fibrosis-related proteins in both cardiomyocytes and cardiac fibroblasts, whereas OPG inhibition can abolish the above-mentioned changes. Consistent with the in vitro data, our in vivo study revealed that the OPG administration induced the LVH in hypertensive rats. This study is the first to report the close association between OPG and LVH development in EH patients and the regulatory effect of OPG on cardiomyocytes and cardiac fibroblasts.

Circulating osteoprotegerin and asymptomatic carotid atherosclerosis in postmenopausal non diabetic women

PURPOSE

Osteoprotegerin (OPG) is a bone metabolism regulator but it is also involved in vascular calcification. Its role in the development of atherosclerosis is still a subject of debate. Postmenopausal women seem to have an increased risk for cardiovascular disease. The aim of the study is to evaluate the relationship between serum OPG and asymptomatic carotid atherosclerosis in postmenopausal non-diabetic women.

MATERIAL/METHODS

Carotid artery examination was performed in 100 postmenopausal women without diabetes mellitus and overt cardiovascular disease, using B-mode ultrasonography to determine the carotid intima-media thickness (CIMT) and the presence of plaques. Serum OPG was measured in all study participants and its relationship with clinical, biochemical and vascular parameters was evaluated.

RESULTS

CIMT correlated with age (r=0.45, p<0.001), years since menopause (r=0.30, p=0.003), abdominal circumference (r=0.25, p=0.01) and OPG (r=0.23, p=0.02). Carotid plaques correlated with age (p<0.001), obesity (p=0.03), abdominal circumference (p=0.03) and CIMT (p<0.001), but not with serum OPG (p=0.86). In regression analyses the independent predictors for CIMT were age (β=0.717, p<0.001), OPG (β=0.214, p=0.02), and years since menopause (β=-0.334, p=0.04) and for the presence of carotid plaques were obesity (p=0.04, OR=3.90), CIMT (p<0.001, OR=6408.86) and smoking (p=0.02, OR=687.93).

CONCLUSION

OPG is associated with cardiovascular risk factors, CIMT, but not with the presence of asymptomatic carotid plaques in non diabetic postmenopausal women. OPG may be a marker of cardiovascular risk.

Osteoprotegerin is associated with subclinical left ventricular systolic dysfunction in diabetic hypertensive patients: a speckle tracking study

BACKGROUND

Recently, the role of osteoprotegerin (OPG) in the pathogenesis of heart failure through different mechanisms has received much attention. Subclinical changes in left ventricular (LV) function can be identified using quantification of myocardial strain, and global longitudinal strain (GLS) is a superior predictor of outcomes than ejection fraction. We hypothesized that increased OPG levels could predict subclinical LV systolic dysfunction in treated diabetic hypertensive patients with preserved LV ejection fraction.

METHODS

The study was composed of 86 diabetic hypertensive and 30 nondiabetic hypertensive patients. All patients underwent echocardiography and venous blood samples were taken for determination of OPG. The relation between OPG levels and LV GLS was investigated using 2-dimensional speckle tracking echocardiography.

RESULTS

Diabetic hypertensive patients had higher diastolic peak early/early diastolic tissue velocity and lower systolic tissue velocity, GLS, GLS rate systolic, and GLS rate early diastolic than nondiabetic hypertensive patients (P = 0.009, P = 0.049, P < 0.001, P = 0.004, and P < 0.001, respectively). Diabetic hypertensive patients were divided into 2 groups according to median GLS value (> 18.5 and ≤ 18.5). The patients with GLS ≤ 18.5 had higher diastolic blood pressure (mm Hg; P = 0.048), OPG (pmol/L; P < 0.001), and hemoglobin A1c (%; P = 0.042) values than those with GLS > 18.5. In multivariate logistic regression analysis, OPG was found to be an independent predictor of impaired GLS (P = 0.001). Receiver operating characteristic curve analysis revealed that OPG values of > 6.45 (pmol/L) identified the patients with GLS ≤ 18.5.

CONCLUSIONS

Plasma OPG values could predict subclinical LV systolic dysfunction in diabetic hypertensive patients.

Elevated levels of plasma osteoprotegerin are associated with all-cause mortality risk and atherosclerosis in patients with stages 3 to 5 chronic kidney disease

Osteoprotegerin (OPG) regulates bone mass by inhibiting osteoclast differentiation and activation, and plays a role in vascular calcification. We evaluated the relationship between osteoprotegerin levels and inflammatory markers, atherosclerosis, and mortality in patients with stages 3-5 chronic kidney disease. A total of 145 subjects (median age 61 years, 61% men; 36 patients on hemodialysis, 55 patients on peritoneal dialysis, and 54 patients with stages 3-5 chronic kidney disease) were studied. Clinical characteristics, markers of mineral metabolism (including fibroblast growth factor-23 [FGF-23]) and inflammation (high-sensitivity C-reactive protein [hsCRP] and interleukin-6 [IL-6]), and the intima-media thickness (IMT) in the common carotid arteries were measured at baseline. Cardiac function was assessed by color tissue Doppler echocardiography. After 36 months follow-up, the survival rate by Kaplan-Meier analysis was significantly different according to OPG levels (χ²=14.33; P=0.002). Increased OPG levels were positively associated with IL-6 (r=0.38, P<0.001), FGF-23 (r=0.26, P<0.001) and hsCRP (r=0.0.24, P=0.003). In addition, OPG was positively associated with troponin I (r=0.54, P<0.001) and IMT (r=0.39, P<0.0001). Finally, in Cox analysis, only OPG (HR=1.07, 95%CI=1.02-1.13) and hsCRP (HR=1.02, 95%CI=1.01-1.04) were independently associated with increased risk of death. These results suggested that elevated levels of serum OPG might be associated with atherosclerosis and all-cause mortality in patients with chronic kidney disease.

TWEAK-Fn14 Cytokine-Receptor Axis: A New Player of Myocardial Remodeling and Cardiac Failure

Tumor necrosis factor (TNF) has been firmly established as a pathogenic factor in heart failure, a significant socio-economic burden. In this review, we will explore the role of other members of the TNF/TNF receptor superfamily (TNFSF/TNFRSF) in cardiovascular diseases (CVDs) focusing on TWEAK and its receptor Fn14, new players in myocardial remodeling and heart failure. The TWEAK/Fn14 pathway controls a variety of cellular activities such as proliferation, differentiation, and apoptosis and has diverse biological functions in pathological mechanisms like inflammation and fibrosis that are associated with CVDs. Furthermore, it has recently been shown that the TWEAK/Fn14 axis is a positive regulator of cardiac hypertrophy and that deletion of Fn14 receptor protects from right heart fibrosis and dysfunction. We discuss the potential use of the TWEAK/Fn14 axis as biomarker for CVDs as well as therapeutic target for future treatment of human heart failure based on supporting data from animal models and in vitro studies. Collectively, existing data strongly suggest the TWEAK/Fn14 axis as a potential new therapeutic target for achieving cardiac protection in patients with CVDs.

Osteoprotegerin (OPG) as a biomarker for diabetic cardiovascular complications

Osteoprotegerin (OPG) is a glycoprotein involved in bone metabolisms and with a regulatory role in immune, skeletal and vascular systems. Recently, circulating OPG levels have emerged as independent biomarkers of cardiovascular disease (CVD) in patients with acute or chronic heart disease, as well as in the healthy population. Furthermore, OPG has been implicated in various inflammations and linked to diabetes and poor glycaemic control. This review focuses on the relations between circulating OPG levels and cardiovascular complications, with special emphasis on diabetic patients. OPG levels were observed to increase concurrently with the severity of diabetic complications, that is, with the highest circulating OPG levels observed in diabetic patients dying from CVD. Although the clinical prognostic use of OPG may seem far away, OPG does look promising as a biomarker in order to help the cardiologist to a better risk-stratification of the patients.

The role of osteoprotegerin in cardiovascular disease

Osteoprotegerin (OPG) is a 401 amino acid N-glycosylated protein, which is highly expressed in a large number of tissues. OPG mainly binds to two ligands, i.e. RANKL (receptor activator of nuclear factor κB ligand) and TRAIL (tumor necrosis factor- related apoptosis-inducing ligand). Upon binding to the former ligand, OPG inhibits the activation of osteoclasts and promotes apoptosis of osteoclasts, whereas the binding of OPG with TRAIL prevents apoptosis of tumor cells. There is now emerging evidence that OPG participates in the pathogenesis of atherosclerosis and cardiovascular diseases by amplifying the adverse effects of inflammation and several traditional risk factors such as hyperlipidemia, endothelial dysfunction, diabetes mellitus, and hypertension. Some epidemiological studies also showed a positive association between OPG levels and cardiovascular morbidity and mortality. The aim of this article is to provide an overview of the main biochemical, physiological, and pathological aspects of OPG biology in cardiovascular disease.

Multimarker Risk Assessment Including Osteoprotegerin and CXCL16 in Acute Coronary Syndromes

Objective—

CXCL16 and osteoprotegerin (OPG) both predict mortality in acute coronary syndromes. We hypothesized that a combination of CXCL16 and OPG concentrations would add prognostic information to the Global Registry of Acute Coronary Events (GRACE) score in patients hospitalized for acute coronary syndromes.

Methods and Results—

We assessed the associations between circulating OPG and soluble CXCL16 levels, obtained within 24 hours of admission (day 1) and after 3 months, and mortality, heart failure and reinfarction in 1322 patients admitted with acute coronary syndromes. After adjustment for the GRACE score, medication, diabetes mellitus and sex, the combination of high values (fourth quartile) for OPG and CXCL16 at baseline was associated with increased short-term (3 months) cardiovascular mortality (hazard ratio, 3.28; 95% CI, 1.84–5.82; P <0.0001). The combined high values were also significantly associated with the long-term (median 91 months) prognosis after adjustment, with hazard ratios 2.18 for cardiovascular mortality (95% CI, 1.62–2.92; P <0.0001), and 2.22 for heart failure (95% CI, 1.67–2.96; P <0.0001). These long-term associations remained significant after further adjustment for left ventricular ejection fraction, C-reactive protein, and pro B-type natriuretic peptide. For 635 patients with blood samples within 24 hours and at 3 months, the combination of high CXCL16 and OPG values (fourth quartile) in the early or stable phase was of a similar order associated with mortality and morbidity beyond 3 months.

Conclusion—

Circulating CXCL16 and OPG are independent predictors of long-term mortality and heart failure development in acute coronary syndromes patients, even after extensive adjustments. Their combination gives more information than either marker alone.

Osteoprotegerin and cardiovascular mortality in patients with non-ST elevation acute coronary syndromes

OBJECTIVE

To assess the relationship between osteoprotegerin (OPG) and cardiovascular death, and the pathobiological mechanisms contributing to the association, in acute coronary syndromes (ACS).

DESIGN

Prospective observational.

SETTING

Biomarker substudy of MERLIN-TIMI 36, a randomised, placebo controlled trial of ranolazine in non-ST elevation (NSTE)-ACS.

PATIENTS

4463 patients with NSTE-ACS.

INTERVENTIONS

Ranolazine or placebo.

MAIN OUTCOME MEASURES

Incidence of cardiovascular death (CV death); additionally, heart failure (HF), cardiac arrhythmias, in-hospital ischaemia, severe recurrent ischaemia or recurrent myocardial infarction (MI).

RESULTS

During a median follow-up of 341 days, 208 patients died of cardiovascular causes. The OPG baseline concentration was strongly associated with both 30 day and 1 year incidence of CV death. After adjustment for conventional risk markers, OPG concentrations (log transformed) remained a significant predictor of CV death by 30 days (HR (95% CI) 2.32 (1.30 to 4.17); p=0.005) and by 1 year (HR 1.85 (1.33 to 2.59); p<0.001). Baseline levels of OPG were also an independent predictor of new or worsening HF at 30 days (HR 2.25 (1.38 to 3.69); p=0.001) and 1 year (HR 1.81 (1.26 to 2.58) p=0.001). By univariable analysis, higher OPG was associated with both early ischaemic and arrhythmic events. Although OPG levels were associated with recurrent MI within 12 months, this association was attenuated and no longer significant after multivariable adjustment.

CONCLUSIONS

OPG is independently associated with 30 day and 1 year risk of cardiovascular mortality and HF development after NSTE-ACS. As no independent relationship between OPG levels and recurrent ischaemia or MI was observed, myocardial dysfunction may be a more important stimulus for OPG production than ischaemia in ACS.

Correlates of osteoprotegerin and association with aortic pulse wave velocity in patients with chronic kidney disease

BACKGROUND AND OBJECTIVES

Osteoprotegerin (OPG), a cytokine that regulates bone resorption, has been implicated in the process of vascular calcification and stiffness.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Serum OPG was measured in 351 participants with chronic kidney disease (CKD) from one site of the Chronic Renal Insufficiency Cohort Study. Cortical bone mineral content (BMC) was measured by quantitative computed tomography in the tibia. Multivariable linear regression was used to test the association between serum OPG and traditional cardiovascular risk factors, measures of abnormal bone and mineral metabolism, and pulse wave velocity.

RESULTS

Higher serum OPG levels were associated with older age, female gender, greater systolic BP, lower estimated GFR, and lower serum albumin. OPG was not associated with measures of abnormal bone or mineral metabolism including serum phosphorus, albumin-corrected serum calcium, intact parathyroid hormone, bone-specific alkaline phosphatase, or cortical BMC. Among 226 participants with concurrent aortic pulse wave velocity measurements, increasing tertiles of serum OPG were associated with higher aortic pulse wave velocity after adjustment for demographics, traditional vascular risk factors, and nontraditional risk factors such as estimated GFR, albuminuria, serum phosphate, corrected serum calcium, presence of secondary hyperparathyroidism, serum albumin, and C-reactive protein or after additional adjustment for cortical BMC in a subset (n = 161).

CONCLUSIONS

These data support a strong relationship between serum OPG and arterial stiffness independent of many potential confounders including traditional cardiovascular risk factors, abnormal bone and mineral metabolism, and inflammation.

The role of osteoprotegerin (OPG) receptor activator for nuclear factor kappaB ligand (RANKL) in cardiovascular pathology - a review

Initially described as key regulators in metabolic bone disease osteoprotegerin (OPG), receptor activator of nuclear factor kappa B (RANK) and RANK ligand (RANKL) have also been discriminated as regulators in immunologic function. Cardiovascular diseases (CVD) develop over many years in life and are often triggered by inflammatory processes within the vessel wall that lead to vascular remodeling. Recently some study groups have described OPG as a prognostic parameter for mortality and morbidity in cardiovascular patients.

Association of plasma osteoprotegerin and adiponectin with arterial function, cardiac function and metabolism in asymptomatic type 2 diabetic men

BACKGROUND

Osteoprotegerin (OPG), a soluble member of the tumor necrosis factor receptor superfamily, is linked to cardiovascular disease. Negative associations exist between circulating OPG and cardiac function. The adipocytokine adiponectin (ADPN) is downregulated in type 2 diabetes mellitus (T2DM) and coronary artery disease and shows an inverse correlation with insulin sensitivity and cardiovascular disease risk. We assessed the relationship of plasma OPG and ADPN and arterial function, cardiac function and myocardial glucose metabolism in T2DM.

METHODS

We included 78 asymptomatic men with uncomplicated, well-controlled T2DM, without inducible ischemia, assessed by dobutamine-stress echocardiography, and 14 age-matched controls. Cardiac function was measured by magnetic resonance imaging, myocardial glucose metabolism (MMRglu) by 18F-2-fluoro-2-deoxy-D-glucose positron emission tomography. OPG and ADPN levels were measured in plasma.

RESULTS

T2DM patients vs. controls showed lower aortic distensibility, left ventricular (LV) volumes, impaired LV diastolic function and MMRglu (all P < 0.05). In T2DM men vs. controls, OPG levels were higher (P = 0.02), whereas ADPN concentrations were decreased (P = 0.04). OPG correlated inversely with aortic distensibility, LV volumes and E/A ratio (diastolic function), and positively with LV mass/volume ratio (all P < 0.05). Regression analyses showed the associations with aortic distensibility and LV mass/volume ratio to be independent of age-, blood pressure- and glycated hemoglobin (HbA1c). However, the associations with LV volumes and E/A ratio were dependent of these parameters. ADPN correlated positively with MMRglu (P < 0.05), which, in multiple regression analysis, was dependent of whole-body insulin sensitivity, HbA1c and waist.

CONCLUSIONS

OPG was inversely associated with aortic distensibility, LV volumes and LV diastolic function, while ADPN was positively associated with MMRglu. These findings indicate that in asymptomatic men with uncomplicated T2DM, OPG and ADPN may be markers of underlying mechanisms linking the diabetic state to cardiac abnormalities.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN53177482.

FGF-23 and osteoprotegerin are independently associated with myocardial damage in chronic kidney disease stages 3 and 4. Another link between chronic kidney disease-mineral bone disorder and the heart

BACKGROUND

Extra-skeletal calcification and disordered phosphate metabolism are hallmarks of chronic kidney disease-mineral bone disorder (CKD-MBD). Osteoprotegerin (OPG) and fibroblast growth factor 23 (FGF-23) are increased in chronic kidney disease (CKD) and have been associated with arterial and cardiac dysfunction and reduced survival. Troponin T (cTnT) is released from cardiac myocytes under conditions of stress and is predictive of mortality across a range of renal functions. However, the utility of this biomarker was formerly limited by the lower limit of assay detection. The introduction of a high-sensitivity assay has enabled more detailed study of myocyte stress below the previous limit of detection. We studied the association of mediators of CKD-MBD with arterial stiffness and also of these mediators and arterial stiffness with myocardial damage in patients with CKD stages 3-4.

METHODS

OPG and FGF-23 were measured in 200 CKD stages 3-4 patients. cTnT was measured using a high-sensitivity assay. Aortic stiffness was assessed using aortic pulse wave velocity (APWV).

RESULTS

Mean age was 69 ± 11 years, mean systolic and diastolic blood pressure was 151 ± 22/81 ± 11 mmHg and renal function was 33 ± 11 mL/min/1.73 m(2). OPG, FGF-23, high-sensitivity troponin T (hs-cTnT) and APWV all correlated with renal function. After multivariate analysis, OPG and age remained independently associated with aortic stiffness. OPG and FGF-23 were independently associated with hs-cTnT in addition to other non-traditional risk factors (Model R(2) = 0.596).

CONCLUSION

We have shown that changes in bone mediators and phosphate metabolism induced by CKD are independently associated with vascular and cardiomyocyte dysfunction. Our findings suggest that cardiac dysfunction may be specifically associated with such abnormalities in addition to recognized increases in vascular stiffness.

Similar to adiponectin, serum levels of osteoprotegerin are associated with obesity in healthy subjects

An increase in serum osteoprotegerin (OPG) is associated with type 2 diabetes mellitus, the severity of vascular calcification, and coronary artery disease. Obesity is a risk factor for diabetes and cardiovascular disease, but little is known about the relationship between OPG and obesity. The purpose of this study was to determine if changes in body mass index (BMI) and insulin sensitivity influence circulating OPG in healthy subjects. A total of 100 subjects (36 lean, 41 overweight, and 23 obese) with normal glucose tolerance, blood pressure, and electrocardiogram stress test result volunteered for this study. Insulin sensitivity was estimated using a 2-hour oral glucose tolerance test with oral glucose insulin sensitivity analysis. Osteoprotegerin, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL),soluble receptor activator of nuclear factor-κβ ligand (sRANKL), and adiponectin were analyzed using commercially available enzyme-linked immunosorbent assays. Osteoprotegerin (P < .01) and adiponectin (P < .001) were significantly decreased in the obese compared with lean subjects. There was no significant difference between BMI categories for TRAIL or sRANKL. Controlling for age and sex, there was a significant correlation between OPG and adiponectin (r = 0.391, P < .001), BMI (r = -0.331, P < .001), waist circumference (r = -0.268, P < .01), homeostasis model assessment of insulin resistance (r = -0.222, P < .05), and oral glucose insulin sensitivity (r = 0.221, P < .05). Both OPG and adiponectin were negatively correlated with body weight, BMI, waist circumference, and fasting plasma insulin while being positively correlated with insulin sensitivity (P < .05). Controlling for age, sex, and BMI, TRAIL was positively related to fat mass (r = 0.373, P < .001) and waist circumference (r = 0.257, P < .05). In contrast to patients with type 2 diabetes mellitus, circulating OPG is lower in obese, but otherwise healthy subjects and is positively correlated with indices of insulin sensitivity.

Association of increased parathyroid hormone with neuroendocrine activation and endothelial dysfunction in elderly men with heart failure

High PTH levels have been reported in patients with chronic heart failure (CHF). Similarly, its levels increase with aging and are related to impaired survival in elderly adults. However, its relationship with neuroendocrine activation and endothelial dysfunction in CHF has not been previously studied. Seventy-three CHF males with New York Heart Association (NYHA) classes II and III and 20 control subjects aged ≥ 55 yr were recruited. PTH, 25-hydroxyvitamin D [25(OH)D], N-terminal pro-brain natriuretic peptide (NT-pro-BNP), adiponectin, and osteoprotegerin were measured. Endothelial function (brachial flow mediated dilation), echocardiography, physical performance, and quality of life were assessed, as well. CHF patients had markedly increased serum PTH (77 ± 33 vs 40 ± 11 pg/ml, p<0.0001), NT-pro-BNP [1809 (2742) vs 67 (74) pg/ml, p<0.0001], adiponectin (17 ± 9 vs 10 ± 2 μg/ml, p<0.0001), osteoprotegerin, whereas 25(OH)D levels were decreased compared to controls. Increased PTH is positively correlated with NTpro- BNP (r=0.399, p<0.0001), adiponectin (r=0.398, p<0.0001), and osteoprotegerin, whereas negatively with 25(OH)D in CHF patients. Additionally, increased serum PTH was associated with endothelial dysfunction, echocardiographic variables of heart failure progression, impaired physical performance, and deteriorated quality of life. In a multivariate linear regression analysis, increased serum PTH was independently associated with neuroendocrine activation (NT-pro-BNP, adiponectin) and endothelial dysfunction in elderly CHF men (R2=0.455). Additionally, demonstrated relations with other well-established variables of heart failure severity suggest the potential role of serum PTH in the pathogenesis and non-invasive monitoring of heart failure progression. Future studies are needed to evaluate the predictive value of serum PTH for clinical outcomes as well as beneficial potential of PTH suppression in CHF patients.

Prognostic value of osteoprotegerin in chronic heart failure: The GISSI-HF trial

BACKGROUND

Circulating levels of osteoprotegerin (OPG), a member of the tumor necrosis factor receptor superfamily, is predictive of death and hospitalization for heart failure after acute coronary syndrome. The association between OPG and outcome in patients with chronic heart failure (CHF) is unknown.

METHODS

Plasma OPG levels at baseline were assessed in 1,229 patients with CHF recruited from 51 clinical centers and included in the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico-Heart Failure (GISSI-HF) trial. Patients were randomized to n-3 polyunsaturated fatty acids (1 g/d) or rosuvastatin (10 mg/d) versus placebo. Osteoprotegerin was analyzed by enzyme-linked immunosorbent assay. The association between OPG and outcome was assessed by Cox proportional hazards regression models.

RESULTS

During a median follow-up time of 3.9 years, 332 patients died; and 791 patients died or were hospitalized because of cardiovascular causes. By univariate analysis, baseline OPG levels were strongly associated with the incidence of death (hazard ratio {HR} [95% CI] 1.53 [1.40-1.67] per 1-SD increase in log OPG). After adjustment for conventional risk markers, OPG remained a significant predictor of death (HR [95% CI] 1.20 [1.06-1.35], P < .001). Similar findings were observed for the composite end point (HR [95% CI] 1.34 [1.07-1.69], P = .012).

CONCLUSION

In patients with CHF, OPG is associated with the incidence of death independently of conventional cardiovascular risk factors.

Association of serum osteoprotegerin with left ventricular mass in African American adults with hypertension

BACKGROUND

African-Americans with hypertension are susceptible to left ventricular hypertrophy (LVH). Serum osteoprotegerin level has been reported to be associated with LVH. We investigated the association of osteoprotegerin with LV mass (LVM) in 898 African-Americans with hypertension (mean age 65 years, 71% women).

METHODS

Osteoprotegerin levels were measured in serum by an immunoassay and log-transformed for analyses. LVM index (LVMi; LVM/height(2.7)) was estimated using M-mode echocardiography. Linear regression analyses using generalized estimating equations were used to assess the association of osteoprotegerin with LVMi.

RESULTS

Serum osteoprotegerin was correlated with LVMi (r = 0.21; P < 0.0001), an estimated increase in LVMi of 5.05 (95% confidence interval 2.93, 7.17) g/m(2.7) in the highest compared to the lowest osteoprotegerin quartile. This association remained statistically significant after adjustment for conventional cardiovascular risk factors (age, sex, body mass index (BMI), history of smoking, diabetes, systolic blood pressure (BP), total and high-density lipoprotein cholesterol), estimated renal function, history of myocardial infarction and stroke, lifestyle factors (physical activity score, years of education, amount of alcohol consumption), medications (aspirin, antihypertensives, statins, estrogens), and C-reactive protein (CRP) (P = 0.02). Additionally, osteoprotegerin was correlated with early/atrial (E/A) ratio (r = -0.16; P < 0.0001), LV mean wall thickness (r = 0.17; P < 0.0001) and relative wall thickness (r = 0.14; P < 0.0001) but not ejection fraction (r = 0.04; P = 0.24) or internal end-diastolic dimension (r = 0.02; P = 0.60).

CONCLUSION

In African-Americans with hypertension, a higher serum osteoprotegerin level is weakly but independently associated with a higher LVM.

Osteoprotegerin as a predictor of coronary artery disease and cardiovascular mortality and morbidity

Osteoprotegerin (OPG) is a glycoprotein that acts as a decoy receptor for receptor activator of nuclear factor kappaB ligand (RANKL) and tumor necrosis factor-related apoptosis-inducing ligand. The OPG/RANKL/receptor activator of nuclear factor kappaB axis plays an important regulatory role in the skeletal, immune, and vascular systems. The protective role of OPG, in animal models, against vascular calcification has not been replicated in human trials; moreover, increased OPG levels have been consistently associated with the incidence and prevalence of coronary artery disease. There seems to be some dichotomy in the role of OPG, RANKL, and tumor necrosis factor-related apoptosis-inducing ligand in atherosclerosis and plaque stability. In this review, we integrate the findings from some of the important studies and try to draw conclusions with a view to gaining some insight into the complex interactions of the OPG/RANKL/receptor activator of nuclear factor kappaB axis and tumor necrosis factor-related apoptosis-inducing ligand in the pathophysiology of atherosclerosis.