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

Plasma levels of PRO-C3, a type III collagen synthesis marker, are associated with arterial stiffness and increased risk of cardiovascular death

BACKGROUND AND AIMS

The N-terminal propeptide of type III collagen (PRO-C3) assay measures a pro-peptide released during type III collagen synthesis, an important feature of arterial stiffening and atherogenesis. There is a clinical need for improved non-invasive, cheap and easily accessible methods for evaluating individuals at risk of cardiovascular disease (CVD). In this study, we investigate the potential of using circulating levels of PRO-C3 to mark the degree of vascular stenosis and risk of cardiovascular events.

METHODS

Baseline plasma levels of PRO-C3 were measured by ELISA in subjects belonging to the SUrrogate markers for Micro- and Macro-vascular hard endpoints for Innovative diabetes Tools (SUMMIT) cohort (N = 1354). Associations between PRO-C3 levels with vascular characteristics, namely stiffness and stenosis, and risk of future cardiovascular events were explored. Subjects were followed up after a median of 35 months (interquartile range 34-36 months), with recorded outcomes cardiovascular death and all-cause mortality.

RESULTS

We found a correlation between PRO-C3 levels and pulse wave velocity (rho 0.13, p = 0.000009), a measurement of arterial stiffness. Higher PRO-C3 levels were also associated with elevated blood pressure (rho 0.07, p = 0.014), as well as risk of cardiovascular mortality over a three-year follow-up period (OR 1.56, confidence interval 1.008-2.43, p = 0.046).

CONCLUSIONS

Elevated circulating PRO-C3 levels are associated with arterial stiffness and future cardiovascular death, in the SUMMIT cohort, suggesting a potential value of PRO-C3 as a novel marker for declining vascular health.

Evaluation of Risk of Cardiac or Cerebrovascular Events in Romosozumab Users Focusing on Comorbidities: Analysis of the Japanese Adverse Drug Event Report Database

Background: Romosozumab is associated with an increased risk of cardiac or cerebrovascular events. Identifying the risk factors for these events could contribute to the safe use of romosozumab. Objective: This study aimed to investigate risk factors for cardiac or cerebrovascular events in romosozumab users. Methods: First, disproportionality analysis was performed to compare the frequency of cardiac or cerebrovascular events, using data from the Japanese Adverse Drug Event Report database. Next, multivariate logistic analysis was performed to investigate risk factors for cardiac or cerebrovascular events in romosozumab users. Results: In total, 859 romosozumab users were identified. A disproportionality of both cardiac and cerebrovascular events was observed in only romosozumab users. Multivariate logistic analysis revealed that the risk of cardiac events in romosozumab users was significantly increased in patients with cardiac disease (odds ratio [OR]: 5.9, 95% confidence interval [CI] 3.5-9.9; P < 0.01) and hypertension (OR: 1.6, 95% CI 1.0-2.7; P = 0.047). In addition, the risk of cerebrovascular events in romosozumab users was significantly increased in the presence of cerebrovascular disease (OR: 2.7, 95% CI 1.2-6.2; P = 0.02) and hypertension (OR: 2.6, 95% CI 1.7-3.9; P < 0.01). Conclusion: Our findings suggest that hypertension may increase the risk of cardiac or cerebrovascular events in romosozumab users. Although additional studies are needed to assess other associated factors, these findings may contribute to the appropriate use of romosozumab and limit adverse events.

Micro-scale assessment of bone quality changes in adult cadaveric men with congestive hepatopathy

Congestive hepatopathy (CH) is a chronic liver disease (CLD) caused by impaired hepatic venous blood outflow, most frequently resulting from congestive heart failure. Although it is known that heart failure and CLDs contribute to increased risk for age-related fractures, an assessment of CH-induced skeletal alterations has not been made to date. The aim of our study was to characterize changes in bone quality in adult male cadavers with pathohistologically confirmed CH compared with controls without liver disease. The anterior mid-transverse part of the fifth lumbar vertebral body was collected from 33 adult male cadavers (age range 43-89 years), divided into the CH group (n = 15) and the control group (n = 18). We evaluated trabecular and cortical micro-architecture and bone mineral content (using micro-computed tomography), bone mechanical competence (using Vickers micro-hardness tester), vertebral cellular indices (osteocyte lacunar network and bone marrow adiposity), and osteocytic sclerostin and connexin 43 expression levels (using immunohistochemistry staining and analysis). Deterioration in trabecular micro-architecture, reduced trabecular and cortical mineral content, and decreased Vickers microhardness were noted in the CH group (p < 0.05). Reduced total number of osteocytes and declined connexin 43 expression levels (p < 0.05) implied that harmed mechanotransduction throughout the osteocyte network might be present in CH. Moreover, elevated expression levels of sclerostin by osteocytes could indicate the role of sclerostin in mediating low bone formation in individuals with CH. Taken together, these micro-scale bone alterations suggest that vertebral strength could be compromised in men with CH, implying that vertebral fracture risk assessment and subsequent therapy may need to be considered in these patients. However, further research is required to confirm the clinical relevance of our findings.

Arterial Stiffness and the Canonical WNT/β-catenin Pathway

PURPOSE OF REVIEW

Arterial stiffness (AS) was mainly associated with cardiovascular morbidity and mortality in a hypertensive patient. Some risk factors contribute to the development of AS, such as aging, high blood pressure, vascular calcification, inflammation, and diabetes mellitus. The WNT/β-catenin pathway is implicated in numerous signaling and regulating pathways, including embryogenesis, cell proliferation, migration and polarity, apoptosis, and organogenesis. The activation of the WNT/β-catenin pathway is associated with the development of these risk factors.

RECENT FINDINGS

Aortic pulse wave velocity (PWV) is measured to determine AS, and in peripheral artery disease patients, PWV is higher than controls. An augmentation in PWV by 1 m/s has been shown to increase the risk of cardiovascular events by 14%. AS measured by PWV is characterized by the deregulation of the WNT/β-catenin pathway by the inactivation of its two inhibitors, i.e., DKK1 and sclerostin. Thus, this review focuses on the role of the WNT/β-catenin pathway which contributes to the development of arterial stiffness.

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.

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.

Serum Sclerostin Is Associated with Peripheral and Central Systolic Blood Pressure in Pediatric Patients with Primary Hypertension

Recent studies showed the significance of the canonical Wnt/beta-catenin pathway and its inhibitor—sclerostin, in the formation of arterial damage, cardiovascular morbidity, and mortality. The study aimed to assess serum sclerostin concentration and its relationship with blood pressure, arterial damage, and calcium-phosphate metabolism in children and adolescents with primary hypertension (PH). Serum sclerostin concentration (pmol/L) was evaluated in 60 pediatric patients with PH and 20 healthy children. In the study group, we also assessed calcium-phosphate metabolism, office peripheral and central blood pressure, 24 h ambulatory blood pressure, and parameters of arterial damage. Serum sclerostin did not differ significantly between patients with PH and the control group (36.6 ± 10.6 vs. 41.0 ± 11.9 (pmol/L), p = 0.119). In the whole study group, sclerostin concentration correlated positively with height Z-score, phosphate, and alkaline phosphatase, and negatively with age, peripheral systolic and mean blood pressure, and central systolic and mean blood pressure. In multivariate analysis, systolic blood pressure (SBP) and height expressed as Z-scores were the significant determinants of serum sclerostin in the studied children: height Z-score (β = 0.224, (95%CI, 0.017–0.430)), SBP Z-score (β = −0.216, (95%CI, −0.417 to −0.016)). In conclusion, our results suggest a significant association between sclerostin and blood pressure in the pediatric population.

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.

Serum indoxyl sulfate as a potential biomarker of aortic arterial stiffness in coronary artery disease

BACKGROUND AND AIMS

Indoxyl sulfate (IS), a dietary tryptophan metabolite, acts as a cardiotoxin and uremic toxin. High IS levels are associated with chronic kidney disease and cardiovascular diseases. This study investigated the association between serum IS levels and aortic arterial stiffness (AAS) in coronary artery disease (CAD) patients.

METHODS AND RESULTS

The carotid-femoral pulse wave velocity (cfPWV) was measured by the SphygmoCor system and patients with values of >10 m/s were classified in the AAS group. The baseline characteristics were recorded and measured (including biochemical and clinical data). Serum IS levels were determined using liquid chromatography-mass spectrometry. AAS occurred in 50 (34.7%) of 144 patients with CAD. They were older, had higher IS levels and percentages of diabetes, systolic blood pressure, blood urea nitrogen, and creatinine but lower estimated glomerular filtration rates. The IS level and older age significantly correlated with AAS [odds ratio (OR) = 3.834, p = 0.031; OR = 1.095, p = 0.002, respectively]. Furthermore, the serum IS level (β = 0.167, adjusted R² change: 0.026, p = 0.027) had a significant positive correlation with cfPWV.

CONCLUSIONS

Taken together, higher serum IS levels are potential independent biomarkers for AAS in patients with CAD. Therefore, early checking of serum IS levels may help prevent CAD progression and have clinical implications in the near future.

Evaluating the cardiovascular safety of sclerostin inhibition using evidence from meta-analysis of clinical trials and human genetics

Inhibition of sclerostin is a therapeutic approach to lowering fracture risk in patients with osteoporosis. However, data from phase 3 randomized controlled trials (RCTs) of romosozumab, a first-in-class monoclonal antibody that inhibits sclerostin, suggest an imbalance of serious cardiovascular events, and regulatory agencies have issued marketing authorizations with warnings of cardiovascular disease. Here, we meta-analyze published and unpublished cardiovascular outcome trial data of romosozumab and investigate whether genetic variants that mimic therapeutic inhibition of sclerostin are associated with higher risk of cardiovascular disease. Meta-analysis of up to three RCTs indicated a probable higher risk of cardiovascular events with romosozumab. Scaled to the equivalent dose of romosozumab (210 milligrams per month; 0.09 grams per square centimeter of higher bone mineral density), the SOST genetic variants were associated with lower risk of fracture and osteoporosis (commensurate with the therapeutic effect of romosozumab) and with a higher risk of myocardial infarction and/or coronary revascularization and major adverse cardiovascular events. The same variants were also associated with increased risk of type 2 diabetes mellitus and higher systolic blood pressure and central adiposity. Together, our findings indicate that inhibition of sclerostin may elevate cardiovascular risk, warranting a rigorous evaluation of the cardiovascular safety of romosozumab and other sclerostin inhibitors.

Higher Plasma Sclerostin and Lower Wnt Signaling Gene Expression in White Adipose Tissue of Prediabetic South Asian Men Compared with White Caucasian Men

BACKGROUND

South Asians generally have an unfavourable metabolic phenotype compared with white Caucasians, including central obesity and insulin resistance. The Wnt protein family interacts with insulin signaling, and impaired Wnt signaling is associated with adiposity and type 2 diabetes mellitus. We aimed to investigate Wnt signaling in relation to insulin signaling in South Asians compared with white Caucasians.

METHODS

Ten Dutch South Asian men with prediabetes and overweight or obesity and 10 matched Dutch white Caucasians were included. Blood samples were assayed for the Wnt inhibitor sclerostin. Subcutaneous white adipose tissue (WAT) and skeletal muscle biopsies were assayed for Wnt and insulin signaling gene expression with quantitative reverse transcription polymerase chain reaction (Clinicaltrials.gov NCT02291458).

RESULTS

Plasma sclerostin was markedly higher in South Asians compared with white Caucasians (+65%, P<0.01). Additionally, expression of multiple Wnt signaling genes and key insulin signaling genes were lower in WAT in South Asians compared with white Caucasians. Moreover, in WAT in both ethnicities, Wnt signaling gene expression strongly positively correlated with insulin signaling gene expression. In skeletal muscle, WNT10B expression in South Asians was lower, but expression of other Wnt signaling and insulin signaling genes was comparable between ethnicities. Wnt and insulin signaling gene expression also positively correlated in skeletal muscle, albeit less pronounced.

CONCLUSION

South Asian men with overweight or obesity and prediabetes have higher plasma sclerostin and lower Wnt signaling gene expression in WAT compared with white Caucasians. We interpret that reduced Wnt signaling could contribute to impaired insulin signaling in South Asians.

Synergistic effect of sclerostin and angiotensin II receptor 1 polymorphism on arterial stiffening

Aim: We aimed to establish the association between sclerostin (a glycoprotein involved in bone metabolism) and development of pulse wave velocity (PWV) in the general population. Methods: A prospective cohort study with a total of 522 subjects. Aortic PWV was measured twice (at baseline and after approximately 8 years of follow-up) and intraindividual change in PWV per year (ΔPWV/year) was calculated. Results: ΔPWV/year increased across the sclerostin quintiles, but generally in a strong age-dependent manner. However, a significant independent positive association between sclerostin and ΔPWV/year was observed exclusively in C allele carriers of rs5186 polymorphism for the angiotensin II receptor 1 (n = 246). Conclusion: Sclerostin concentrations were associated with an accelerated natural course of arterial stiffening, but only in interaction with renin-angiotension system.

Wnt Pathway Gene Expression Is Associated With Arterial Stiffness

Background

Animal and in vitro experiments implicate the Wnt pathway in cardiac development, fibrosis, vascular calcification, and atherosclerosis, but research in humans is lacking. We examined peripheral blood Wnt pathway gene expression and arterial stiffness in 369 healthy African ancestry men (mean age, 64 years).

Methods and Results

Gene expression was assessed using a custom Nanostring nCounter gene expression panel (N=43 genes) and normalized to housekeeping genes and background signal. Arterial stiffness was assessed via brachial‐ankle pulse‐wave velocity. Fourteen Wnt genes showed detectable expression and were tested individually as predictors of pulse‐wave velocity using linear regression, adjusting for age, height, weight, blood pressure, medication use, resting heart rate, current smoking, alcohol intake, and sedentary lifestyle. Adenomatous polyposis coli regulator of Wnt signaling pathway (APC), glycogen synthase kinase 3β (GSK3B), and transcription factor 4 (TCF4) were significantly associated with arterial stiffness (P<0.05 for all). When entered into a single model, APC and TCF4 expression remained independently associated with arterial stiffness (P=0.04 and 0.003, respectively), and each explained ≈3% of the variance in pulse‐wave velocity.

Conclusions

The current study establishes a novel association between in vivo expression of the Wnt pathway genes, APC and TCF4, with arterial stiffness in African ancestry men, a population at high risk of hypertensive vascular disease.