Serum sclerostin and adverse outcomes in elderly patients with stable coronary artery disease undergoing percutaneous coronary intervention

Cardioprotective function of sclerostin by reducing calcium deposition, proliferation, and apoptosis in human vascular smooth muscle cells

BACKGROUND

Sclerostin is an inhibitor of the Wnt/b-catenin pathway, which regulates bone formation, and can be expressed in vascular smooth muscle cells (VSMCs). Type 2 diabetes (T2D) is associated with an increased risk of cardiovascular disease (CVD) and increased serum and tissue expression of sclerostin. However, whether the role of sclerostin is detrimental or protective in the development of CVD is unknown. Therefore, our aims are to determine the level of sclerostin in T2D patients with/without CVD and in controls, both at serum and vascular tissue, and to analyze the role of sclerostin in VSMCs under calcified environments.

METHODS

Cross-sectional study including 121 controls and 139 T2D patients with/without CVD (48/91). Sclerostin levels in serum were determined by ELISA, and sclerostin expression was analyzed by RT-qPCR and immunohistochemistry in calcified and non-calcified artery of lower limb from T2D patients (n = 7) and controls (n = 3). In vitro experiments were performed in VSMCs (mock and sclerostin overexpression) under calcifying conditions analyzing the sclerostin function by determination of calcium and phosphate concentrations, and quantification of calcium deposits by Alizarin Red. Proliferation and apoptosis were analyzed by MTT assay and flow cytometry, respectively. The regulation of the expression of genes involved in bone metabolism was determined by RT-qPCR.

RESULTS

A significant increase in serum sclerostin levels in T2D patients with CVD compared to T2D patients without CVD and controls (p < 0.001) was observed. Moreover, higher circulating sclerostin levels were independently associated with CVD in T2D patients. Increased sclerostin expression was observed in calcified arteries of T2D patients compared to non-calcified arteries of controls (p = 0.003). In vitro experiments using VSMCs under calcified conditions, revealed that sclerostin overexpression reduced intracellular calcium (p = 0.001), calcium deposits (p < 0.001), cell proliferation (p < 0.001) and promoted cell survival (p = 0.015). Furthermore, sclerostin overexpression exhibited up-regulation of ALPL (p = 0.009), RUNX2 (p = 0.001) and COX2 (p = 0.003) and down-regulation of inflammatory genes, such as, IL1β (p = 0.005), IL6 (p = 0.001) and IL8 (p = 0.003).

CONCLUSIONS

Sclerostin could play a protective role in the development of atherosclerosis in T2D patients by reducing calcium deposits, decreasing proliferation and inflammation, and promoting cell survival in VSMCs under calcifying conditions. Therefore, considering the bone-vascular axis, treatment with anti-sclerostin for bone disease should be used with caution.

Exploring the Role of Sclerostin as a Biomarker of Cardiovascular Disease and Mortality: A Scoping Review

Sclerostin is most recognized for its role in controlling bone formation; however, it is also expressed in the heart, aorta, coronary, and peripheral arteries. Human studies have associated high circulating sclerostin levels with the presence of different cardiovascular diseases (CVD), surrogate CVD markers, and a high risk of cardiovascular events in some populations. However, this is still a matter of scientific debate, as the results have been very heterogeneous among studies. In the present review, the association between serum sclerostin levels and CVD and/or cardiovascular mortality was analyzed. For this purpose, a scoping review was performed in which articles measuring serum sclerostin levels and cardiovascular risk in patients were selected. Eleven articles answered the research question; of these articles, 8/11 evaluated the association between sclerostin and CVD, of which 4/8 found a positive association, 2/8 found a negative association, and 2/8 found no association between variables. Five (5/11) of the articles included in the study evaluated cardiovascular mortality, of which 3/5 found a positive association, 1/5 found a negative association, and 1/5 found no association between variables. In conclusion, we did not find sufficient results to be able to demonstrate an association between elevated sclerostin levels and the development of CVD and/or cardiovascular mortality in the general population due to heterogeneity in the results. However, there seems to be a tendency to consider increased sclerostin levels as a risk factor for both the development of cardiovascular events and cardiovascular mortality in specific populations. Further studies in this field will help to solve some of the inconsistencies found during this scoping review and allow for the future use of sclerostin measurement as a strategy in the prevention and diagnosis of CVD and/or cardiovascular mortality.

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.

Association of serum sclerostin and osteoprotegerin levels with the presence, severity and prognosis in patients with acute myocardial infarction

Background

Bone-related proteins (such as sclerostin and osteoprotegerin [OPG]) are involved in the development of atherosclerosis. However, the relationship between bone-related proteins and acute myocardial infarction (AMI) has not been extensively evaluated. The purpose of this study was to assess the association of serum sclerostin and OPG with the presence, severity and prognosis in patients with AMI.

Methods

This study prospectively enrolled 152 patients attacked by acute chest pain. Serum sclerostin and OPG were detected within the first 24 h after AMI diagnosis by ELISA kits. The AMI predictive efficacy of sclerostin and OPG were analyzed by receiver operating characteristics (ROC) curve. Univariable and multivariable linear regression analyses were performed to determine the association between bone-related proteins and scores indicating the severity of coronary artery occlusion. Moreover, prognostic values were assessed by Kaplan–Meier curves and Cox regression analysis.

Results

There were 92 patients in AMI group, 60 in non-AMI group. Serum levels of sclerostin and OPG were significantly higher in AMI group than in non-AMI group (all p < 0.001), which showed predictive value for the presence of AMI (all p < 0.001). The area under the ROC curve values of sclerostin and OPG were 0.744 and 0.897, respectively. A multivariable linear regression analysis demonstrated that Ln-transformed sclerostin (β = 0.288, p = 0.009) and Ln-transformed OPG (Ln-OPG: β = 0.295, p = 0.019) levels were associated with GENISINI score, independently of conventional clinical parameters. In addition, Ln-OPG levels were still positively associated with GRACE score after adjustments (β = 0.320, p = 0.001). During a 1-year follow-up, patients above the median of sclerostin levels had higher incidence of major adverse cardiac events (MACE) than those below the median (p = 0.028). It was also observed that the MACE rates were higher in patients above the median of OPG levels, though no statistic importance (p = 0.060). After adjusting conventional risk factors by multivariate Cox regression, Ln-OPG was associated with incident MACE (hazard ratio = 2.188 [95% confidence intervals 1.102–4.344], p = 0.025).

Conclusions

Bone-related proteins could exert a potential role in early risk stratification and prognosis assessment in patients with AMI.

Drug discovery of sclerostin inhibitors

Sclerostin, a protein secreted from osteocytes, negatively regulates the WNT signaling pathway by binding to the LRP5/6 co-receptors and further inhibits bone formation and promotes bone resorption. Sclerostin contributes to musculoskeletal system-related diseases, making it a promising therapeutic target for the treatment of WNT-related bone diseases. Additionally, emerging evidence indicates that sclerostin contributes to the development of cancers, obesity, and diabetes, suggesting that it may be a promising therapeutic target for these diseases. Notably, cardiovascular diseases are related to the protective role of sclerostin. In this review, we summarize three distinct types of inhibitors targeting sclerostin, monoclonal antibodies, aptamers, and small-molecule inhibitors, from which monoclonal antibodies have been developed. As the first-in-class sclerostin inhibitor approved by the U.S. FDA, the monoclonal antibody romosozumab has demonstrated excellent effectiveness in the treatment of postmenopausal osteoporosis; however, it conferred high cardiovascular risk in clinical trials. Furthermore, romosozumab could only be administered by injection, which may cause compliance issues for patients who prefer oral therapy. Considering these above safety and compliance concerns, we therefore present relevant discussion and offer perspectives on the development of next-generation sclerostin inhibitors by following several ways, such as concomitant medication, artificial intelligence-based strategy, druggable modification, and bispecific inhibitors strategy.

Low vitamin K status, high sclerostin and mortality risk of stable coronary heart disease patients

Aim: We explored whether matrix Gla protein (MGP, natural calcification inhibitor) and sclerostin (glycoprotein responsible for osteoblast differentiation) interact in terms of mortality risk in coronary patients. Methods: 945 patients after myocardial infarction and/or coronary revascularization were followed in a prospective study. All-cause death, fatal or nonfatal cardiovascular events and heart failure hospitalizations were registered. Results: Either high desphospho-uncarboxylated MGP (dp-ucMGP) or high sclerostin were independently associated with 5-year all-cause/cardiovascular mortality. However, we observed an additional mortality risk in the coincidence of both factors. Concomitantly high dp-ucMGP (≥884 pmol/l) plus sclerostin (≥589 ng/l) were associated with increased all-cause mortality risk compared with 'normal' concentrations of both factors (HRR 3.71 [95% CI: 2.07-6.62, p < 0.0001]), or if only one biomarker has been increased. A similar pattern was observed for fatal, but not for nonfatal cardiovascular events. Conclusion: Concomitantly high MGP and sclerostin indicate increased mortality risk, which probably reflects their role in cardiovascular calcifications.

The Impact of Sclerostin Levels on Long-Term Prognosis in Patients Undergoing Coronary Angiography: A Personalized Approach with 9-Year Follow-Up

Sclerostin might play a role in atherosclerosis development. This study aimed to analyze the impact of baseline sclerostin levels on 9-year outcomes in patients without significant renal function impairment and undergoing coronary angiography. The primary study endpoint was the rate of major cardiovascular events (MACE), defined as a combined rate of myocardial infarction (MI), stroke, or death at 9 years. We included 205 patients with a mean age of 62.9 ± 0.6 years and 70.2% male. Median serum sclerostin concentration was 133.22 pg/mL (IQR 64.0–276.17). At 9 years, in the whole population, the rate of MACE was 34.1% (n = 70), MI: 11.2% (n = 23), stroke: 2.4% (n = 5), and death: 20.5% (n = 42). In the high sclerostin (>median) group, we observed statistically significant higher rates of MACE and death: 25.2% vs. 43.1% (HR 1.75, 95% CI 1.1–2.10, p = 0.02) and 14.6% vs. 26.5% (HR 1.86, 95% CI 1.02–3.41, p = 0.049), respectively. Similar relationships were observed in patients with chronic coronary syndrome and SYNTAX 0–22 subgroups. Our results suggest that sclerostin assessment might be useful in risk stratification, and subjects with higher sclerostin levels might have a worse prognosis.