Plasma levels of sRANKL and OPG are associated with atherogenic cytokines in patients with intermediate cardiovascular risk

Biomarkers of Cardiovascular Risk in Patients With Rheumatoid Arthritis: Results From the TARGET Trial

Cardiovascular disease remains an important comorbidity in patients with rheumatoid arthritis (RA), but traditional models do not accurately predict cardiovascular risk in patients with RA. The addition of biomarkers could improve prediction.

METHODS AND RESULTS

The TARGET (Treatments Against RA and Effect on FDG PET/CT) trial assessed whether different treatment strategies in RA differentially impact cardiovascular risk as measured by the change in arterial inflammation on arterial target to background ratio on fluorodeoxyglucose positron emission tomography/computed tomography scans conducted 24 weeks apart. A group of 24 candidate biomarkers supported by prior literature was assessed at baseline and 24 weeks later. Longitudinal analyses examined the association between baseline biomarker values, measured in plasma EDTA, and the change in arterial inflammation target to background ratio. Model fit was assessed for the candidate biomarkers only, clinical variables only, and models combining both. One hundred nine patients with median (interquartile range) age 58 years (53-65 years), RA duration 1.4 years (0.5-6.6 years), and 82% women had biomarkers assessed at baseline and follow-up. Because the main trial analyses demonstrated significant target to background ratio decreases with both treatment strategies but no difference across treatment groups, we analyzed all patients together. Baseline values of serum amyloid A, C-reactive protein, soluble tumor necrosis factor receptor 1, adiponectin, YKL-40, and osteoprotegerin were associated with significant change in target to background ratio. When selected candidate biomarkers were added to the clinical variables, the adjusted R2 improved from 0.20 to 0.33 (likelihood ratio P=0.0005).

CONCLUSIONS

A candidate biomarker approach identified several promising biomarkers that associate with baseline and treatment-associated changes in arterial inflammation in patients with RA. These will now be tested in an external validation cohort.

Reduced Serum sRANKL and sTREM2 Levels in High-Grade Gliomas: Association with Prognosis

INTRODUCTION

High-grade gliomas (HGG), including Glioblastoma multiforme (GBM), account for the majority of primary brain tumors. Nevertheless, prognostic and diagnostic biomarkers are quite limited for HGG. The objective of this study was to investigate the prognostic value of sRANKL and sTREM2 levels in HGG patients.

METHODS

Twelve consecutive patients with HGG, 14 patients with non-glial tumors (non-GT) and 20 age and gender-matched healthy controls were recruited. Overall survival duration of the patients was recorded. Pre-operative serum levels of sRANKL and sTREM2 were measured by ELISA. Tumors of HGG patients were analyzed by immunohistochemical staining for p53 and Ki67 and percentage scores were calculated.

RESULTS

Patients with HGG and non-GT showed lower serum sRANKL and sTREM2 levels than healthy individuals. Levels of sRANKL were inversely correlated with the overall survival of patients (p=0.002, R=0.787), while sTREM2 levels were inversely correlated with p53 score (p=0.018, R=-0.666) but not survival.

CONCLUSION

Brain tumor patients show suppressed levels of glial activity biomarkers in the peripheral circulation. Serum sRANKL levels may serve as a potential prognostic biomarker for HGG.

Serum TRACP5b, a Marker of Bone Resorption, Is Associated With Adverse Cardiac Prognosis in Hospitalized Patients With Heart Failure

Background

Tartrate-resistant acid phosphatase type 5b (TRACP5b) is derived from osteoclasts, and has been used as a marker of osteoporosis (bone resorption). Although heart failure (HF) is associated with catabolic bone remodelling, serum TRACP5b levels have not been rigourously examined in patients with HF.

Methods

We conducted a prospective observational study of 688 decompensated HF patients who had been discharged and whose TRACP5b had been measured. These patients were divided into tertiles on the basis of serum TRACP5b levels: first (TRACP5b < 316 mU/dL, n = 229), second (TRACP5b 316-489 mU/dL, n = 229), and third (TRACP5b ≥ 490 mU/dL, n = 230). We compared the patient baseline characteristics, exercise capacity, and their postdischarge prognosis, including cardiac mortality and cardiac events such as cardiac death and worsening HF.

Results

Age was significantly higher, and prevalence of female sex and anemia was significantly higher in the third tertile than in the first and second tertiles (P < 0.05, respectively). Circulating TRACP5b levels were correlated with peak breath-by-breath oxygen consumption, but not with left ventricular ejection fraction. In the Kaplan-Meier analysis (mean follow-up, 426 days), cardiac mortality and cardiac event rates progressively increased from the first to the third tertiles (P < 0.05, respectively). In the multivariable Cox proportional hazard analysis, the third tertile was an independent predictor of cardiac mortality and cardiac events (cardiac mortality hazard ratio, 2.493; P = 0.040; cardiac events hazard ratio, 1.687; P = 0.030).

Conclusions

High serum levels of TRACP5b, a marker of bone resorption, are associated with high cardiac mortality and cardiac events, accompanied by impaired exercise capacity.

RANKL and RANK in extracellular vesicles: surprising new players in bone remodeling

Receptor activator of nuclear factor kappa B-ligand (RANKL), its receptor RANK, and osteoprotegerin which binds RANKL and acts as a soluble decoy receptor, are essential controllers of bone remodeling. They also play important roles in establishing immune tolerance and in the development of the lymphatic system and mammary glands. In bone, RANKL stimulates osteoclast formation by binding RANK on osteoclast precursors and osteoclasts. This is required for bone resorption. Recently, RANKL and RANK have been shown to be functional components of extracellular vesicles (EVs). Data linking RANKL and RANK in EVs to biological regulatory roles are reviewed, and crucial unanswered questions are examined. RANKL and RANK are transmembrane proteins and their presence in EVs allows them to act at a distance from their cell of origin. Because RANKL-bearing osteocytes and osteoblasts are often spatially distant from RANK-containing osteoclasts in vivo, this may be crucial for the stimulation of osteoclast formation and bone resorption. RANK in EVs from osteoclasts has the capacity to stimulate a RANKL reverse signaling pathway in osteoblasts that promotes bone formation. This serves to couple bone resorption with bone formation and has inspired novel bifunctional therapeutic agents. RANKL- and RANK- containing EVs in serum may serve as biomarkers for bone and immune pathologies. In summary, EVs containing RANKL and RANK have been identified as intercellular regulators in bone biology. They add complexity to the central signaling network responsible for maintaining bone. RANKL- and RANK-containing EVs are attractive as drug targets and as biomarkers.

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.

Sex Differences in Proatherogenic Cytokine Levels

BACKGROUND

It has been shown that sex affects immunity, including cytokine production. Given that atherosclerosis is an inflammatory disease promoted by specific cytokines, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α, we aimed at evaluating whether sex could affect the levels of these proatherogenic cytokines in a group of healthy adults. In this analysis, we also included other cytokines and peptides that have been implicated in atherosclerosis development and progression.

METHODS

A total of 104 healthy adults were recruited; we measured circulating levels of IL-1β, IL-6, TNF-α, angiotensins and angiotensin-converting enzyme-2 (ACE2), as well as osteoprotegerin and receptor activator of nuclear factor κB ligand (RANKL).

RESULTS

IL-1β, IL-6, and TNF-α were significantly higher in men as compared to women. They were all associated with testosterone and the testosterone/estradiol ratio. They remained significantly associated with sex (but not with hormones) after being tested for potential confounders.

CONCLUSIONS

Sex seems to influence the levels of proatherogenic cytokines. This is consistent not only with sex differences in vulnerability to infections but also with the higher cardiovascular risk exhibited by the male gender as compared to the female gender. Nevertheless, this association is only partly explained by hormone levels.