Osteocalcin value to identify subclinical atherosclerosis over atherosclerotic cardiovascular disease (ASCVD) risk score in middle-aged and elderly Chinese asymptomatic men

Association between serum osteocalcin and atherosclerosis in Type-2 diabetes mellitus: a cross-sectional study

BACKGROUND

The past few decades have seen a marked increase in the macrovascular complications of Type-2 diabetes mellitus (T2DM) such as coronary heart disease, peripheral arterial disease, and cerebrovascular disease. This has been predominantly attributed to the increased atherosclerosis in these patients. Atherosclerosis usually remains an asymptomatic condition and this poses a significant challenge in its early diagnosis and timely intervention. Hence, there is an immediate need for exploring novel tools to aid in the early detection of atherosclerosis, especially in T2DM patients. Osteocalcin (OC), synthesized by osteoblasts, is a protein hormone found in the skeletal system. This protein is considered as a marker for bone density and in recent times has been gaining interest due to its protective role in cerebrovascular diseases(CVD).

METHODS

We conducted a cross-sectional study and evaluated the association between serum OC levels and atherosclerosis in 113 T2DM patients. Carotid intima-media thickness (CC-IMT) was used as an estimate of atherosclerosis and patients were divided into two groups (CC-IMT < 0.9 and ≥ 0.9). Correlation of serum OC levels and glycemic parameters and lipid profiles were studied and compared between both groups.

RESULTS

There is a significant negative correlation between the CC-IMT estimates and serum OC levels. CC-IMT also has a significant association with other biochemical parameters such as fasting blood sugar, glycated hemoglobin and high-density lipoprotein.

CONCLUSION

Although the independent association of serum OC could not be established in the T2DM patient population, overall, the results favor low serum OC as a prognostic marker for atherosclerosis.

Osteocalcin, Osteopontin and RUNX2 Expression in Patients' Leucocytes with Arteriosclerosis

Introduction: Calcification is a highly relevant process in terms of development of cardiovascular diseases, and its prevention may be the key to prevent disease progression in patients. In this study we investigated the expression of osteocalcin (OC), osteopontin (OPN) and RUNX2 in patients’ leukocytes and their possible role as diagnostic markers for cardiovascular diseases. Materials and Methods: Leucocytes from 38 patients were collected in the Department of Surgery of Martin-Luther-University Halle, including 8 patients without arteriosclerotic disease (PAD−) and 30 patients with symptomatic arteriosclerotic disease (PAD+). Patients’ leucocytes, in vitro calcified human umbilical vein endothelial cells (HUVEC) and vascular smooth muscle cells (VSMC) were subjected to qPCR analyses with TaqMan probes, which are specific for OC, OPN and RUNX2. Additionally, the interaction between monocytes and calcified HUVEC and VSMC was investigated in adhesion assays. Results: The leucocytes obtained from patients with symptomatic arteriosclerotic disease (PAD+) demonstrated decreased mRNA level expression of Osteocalcin, while OPN and RUNX2 were significantly upregulated in comparison to asymptomatic patients. The induction of calcification in HUVEC and VSMC cells led to an increased expression of OC, OPN and RUNX2. Immunocytochemistry of calcified HUVEC and VSMC revealed stronger expression of OC, OPN and RUNX2 in calcified cells. Conclusion: To conclude, these data demonstrate that symptomatic arteriosclerotic disease has a correlation with OC, OPN and RUNX2. The biological rationale of OC, OPN and RUNX-2 remains not yet entirely understood for atherosclerotic disease, which means it needs further investigation.

Osteocalcin and vascular function: is there a cross-talk?

Background

The bone-derived protein osteocalcin (OC), in its undercarboxylated (ucOC) form, has a beneficial effect on energy metabolism and may be a future therapeutic target for metabolic diseases. Increasing evidence suggests a link between ucOC and cardiovascular disease (CVD) development; however, the exact relationship is conflicting and unclear.

Scope of review

The aim of this review was to summarise the current research examining the interaction between OC and vascular dysfunction, the initiating stage in the development of atherosclerosis and CVD.

Major conclusions

In humans, the association between OC and vascular function is inconsistent. Several studies report that total OC (tOC) is associated with adverse function or beneficial function, whereas others report that tOC and ucOC has no effect on vascular function. The conflicting data are likely due to several methodological inconsistencies, in particular the lack of studies reporting circulating ucOC levels. In animal models, the direct administration of ucOC to isolated blood vessels ex vivo produced minimal changes in endothelial function, but importantly, no adverse responses. Finally, in human endothelial and vascular smooth muscle cells, ucOC treatment did not influence classical markers of cellular function, including endothelin-1, vascular adhesion molecule-1 and monocyte chemoattractant protein-1 after exposure to high glucose and inflammatory conditions. The lack of adverse effects in ex vivo and in vitro studies suggests that ucOC may be targeted as a future therapeutic for metabolic diseases, without the risk of detrimental effects in the vasculature. However, further studies are needed to confirm these findings and to investigate whether there is a direct beneficial influence of ucOC.

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ucOC is implicated in the regulation of glucose homeostasis; but its role in the vasculature has been minimally reported.

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Studies which examine the association between ucOC and vascular function in humans often report inconsistent outcomes.

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In addition, ex vivo and in vitro studies have reported that ucOC likely does not directly regulate endothelial function.

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ucOC may be targeted as a therapeutic treatment for metabolic diseases without a risk of adverse effects in the vasculature.

The mediating role of the visceral fat area in the correlation between the serum osteocalcin levels and a prolonged QTc interval

AIMS

Osteocalcin, a bone-derived factor, could be a feasible marker for metabolic disorders and adverse cardiovascular outcomes. This study aimed to explore the correlation between serum osteocalcin levels and correct QT interval (QTc) interval prolongation, a risk factor of cardiac morbidity and mortality.

METHODS

We recruited 1210 subjects (age range: 26-80 years) in communities in Shanghai. Serum osteocalcin levels were determined using an electrochemiluminescence immunoassay. The QTc interval was measured using a 12-lead electrocardiogram and was calculated by the Bazett formula. A prolonged QTc interval was defined as QTc > 440 ms. Visceral fat area (VFA) was assessed by magnetic resonance imaging. A VFA of 80 cm² was applied as a cut-off point for central obesity.

RESULTS

Subjects with diabetes, overweight/obesity, or central obesity had significantly lower serum osteocalcin levels than those without (all P < 0.01). In subjects with a normal QTc interval, QTc interval lengthening accompanied decreasing osteocalcin levels (P_{for trend} = 0.033), and the decline was more obvious in subjects with a prolonged QTc interval (P_{for trend} = 0.022). Serum osteocalcin levels were correlated with the QTc interval (standardized β = -0.082, P = 0.005). Neither diabetes nor overweight/obesity was correlated with the QTc interval, whereas central obesity was positively correlated (P = 0.032). In addition, the correlation between osteocalcin levels and the QTc interval was attenuated when central obesity was included in the model simultaneously (standardized β = -0.075, P = 0.010). Mediation analysis revealed that VFA played a mediating role in the aforementioned correlation, and the estimated percentage of the total effect mediated by VFA was 20.9% (P = 0.007).

CONCLUSIONS

VFA partially mediated the inverse correlation between the serum osteocalcin levels and QTc interval, suggesting that improving fat metabolism may be a mechanism by which osteocalcin protects against cardiovascular diseases.

Nontraditional Cardiovascular Biomarkers and Risk Factors: Rationale and Future Perspectives

The primary prevention of cardiovascular (CV) disease depends on the capacity to identify subjects at higher risk long before the occurrence of CV clinical manifestations. Traditional risk factors do not cover fully prediction of individual risk. Moreover, there is an area of gray for patients at intermediate CV risk, which offers wide margins of improvement. These observations highlight the need for new additive tools for a more accurate risk stratification. An increasing number of candidate biomarkers have been identified to predict CV risk and events, although they generally give only a moderate increase when added to currently available predictive scores. The approach utilizing a relative small number of biomarkers in multiple combinations, but only weakly related to each other or unrelated, thus belonging to independent-pathways, and so able to catch the multidimensional characteristic of atherosclerosis, appears promising. We discuss vitamin D and bone turnover biomarkers, hepatitis C virus, and psycho-emotional factors that may reflect alternative pathways over those generally considered for atherosclerosis (e.g., aspects directly related to inflammation and thrombosis). These new biomarkers could facilitate a more accurate assessment of CV risk stratification if incorporated in the current risk assessment algorithms.