Osteoprotegerin and RANKL-RANK-OPG-TRAIL signalling axis in heart failure and other cardiovascular diseases

Vascular Cytokines and Atherosclerosis: Differential Serum Levels of TRAIL, IL-18, and OPG in Obstructive Coronary Artery Disease

The risk-factor-based prediction of atherosclerotic coronary artery disease (CAD) remains suboptimal, particularly in the absence of any of the standard modifiable cardiovascular risk factors (SMuRFs), making the discovery of biomarkers that correlate with atherosclerosis burden critically important. We hypothesized that cytokines and receptors associated with inflammation in CAD-tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), interleukin-18 (IL-18), and osteoprotegerin (OPG)-would be independently associated with CAD. To determine this, we measured the serum biomarker levels of 993 participants from the BioHEART study who had CT coronary angiograms that were scored for severity of stenosis and plaque composition. We found that the quartiles of TRAIL, OPG, and IL-18 were significantly associated with disease scores, and that the IL-18/TRAIL and OPG/TRAIL ratios demonstrated significant differences between no CAD vs. STEMI whereas only the OPG/TRAIL ratio showed differences between no CAD and obstructive CAD (stenosis > 50%). However, these associations did not persist after adjustment for age, sex, SMuRFs, and a family history of CAD. In conclusion, TRAIL, IL-18, and OPG and the derived ratios of IL-18/TRAIL and OPG/TRAIL demonstrate significant associations with raw disease scores and risk factors, but these markers are not discriminatory biomarkers for the prediction of CAD when incorporated into multi-variable risk models.

Single-Cell RNA Sequencing Deconstructs the Distribution of Immune Cells Within Abdominal Aortic Aneurysms in Mice

BACKGROUND

Inflammation is a key component in the development of abdominal aortic aneurysm (AAA), yet insights into the roles of immune cells and their interactions in this process are limited.

METHODS

Using single-cell RNA transcriptomic analysis, we deconstructed the CD45+ cell population in elastase-induced murine AAA at the single-cell level. We isolated each group of immune cells from murine AAA tissue at different time points and divided them into several subtypes, listed the remarkable differentially expressed genes, explored the developmental trajectories of immune cells, and demonstrated the interactions among them.

RESULTS

Our findings reveal significant differences in several immune cell subsets, including macrophages, dendritic cells, and T cells, within the AAA microenvironment compared with the normal aorta. Especially, conventional dendritic cell type 1 exclusively existed in the AAA tissue rather than the normal aortas. Via CellChat analysis, we identified several intercellular communication pathways like visfatin, which targets monocyte differentiation and neutrophil extracellular trap-mediated interaction between neutrophils and dendritic cells, which might contribute to AAA development. Some of these pathways were validated in human AAA.

CONCLUSIONS

Despite the absence of external pathogenic stimuli, AAA tissues develop a complex inflammatory microenvironment involving numerous immune cells. In-depth studies of the inflammatory network shall provide new strategies for patients with AAA.

Autophagy regulates bone loss via the RANKL/RANK/OPG axis in an experimental rat apical periodontitis model

AIM

Autophagy is involved in human apical periodontitis (AP). However, it is not clear whether autophagy is protective or destructive in bone loss via the receptor activator of nuclear factor-κB ligand (RANKL)/RANK/osteoprotegerin (OPG) axis. This study aimed to investigate the involvement of autophagy via the RANKL/RANK/OPG axis during the development of AP in an experimental rat model.

METHODOLOGY

Twenty-four female Sprague-Dawley rats were divided into control, experimental AP (EAP) + saline, and EAP + 3-methyladenine (An autophagy inhibitor, 3-MA) groups. The control group did not receive any treatment. The EAP + saline group and the EAP + 3-MA group received intraperitoneal injections of saline and 3-MA, respectively, starting 1 week after the pulp was exposed. Specimens were collected for microcomputed tomography (micro-CT) scanning, histological processing, and immunostaining to examine the expression of light chain 3 beta (LC3B), RANK, RANKL, and OPG. Data were analysed using one-way analysis of variance (p < .05).

RESULTS

Micro-CT showed greater bone loss in the EAP + 3-MA group than in the EAP + saline group, indicated by an elevated trabecular space (Tb.Sp) (p < .05). Inflammatory cell infiltration was observed in the EAP + saline and EAP + 3-MA groups. Compared with EAP + saline group, the EAP + 3-MA group showed weaker expression of LC3B (p < .01) and OPG (p < .05), more intense expression of RANK (p < .01) and RANKL (p < .01), and a higher RANKL/OPG ratio (p < .05).

CONCLUSION

Autophagy may exert a protective effect against AP by regulating the RANKL/RANK/OPG axis, thereby inhibiting excessive bone loss.

Osteoprotegerin (OPG) and its ligands RANKL and TRAIL in falciparum, vivax and knowlesi malaria: correlations with disease severity, and B cell production of OPG

Osteoprotegerin (OPG) is a soluble decoy receptor for receptor activator of NF-ƙB ligand (RANKL) and TNF-related apoptosis-inducing ligand (TRAIL), and is increasingly recognised as a marker of poor prognosis in a number of diseases. Here we demonstrate that in Malaysian adults with falciparum and vivax malaria, OPG is increased, and its ligands TRAIL and RANKL decreased, in proportion to disease severity. In volunteers experimentally infected with P. falciparum and P. vivax, RANKL was suppressed, while TRAIL was unexpectedly increased, suggesting binding of OPG to RANKL prior to TRAIL. We also demonstrate that P. falciparum stimulates B cells to produce OPG in vitro, and that B cell OPG production is increased ex vivo in patients with falciparum, vivax and knowlesi malaria. Our findings provide further evidence of the importance of the OPG/RANKL/TRAIL pathway in pathogenesis of diseases involving systemic inflammation, and may have implications for adjunctive therapies. Further evaluation of the role of B cell production of OPG in host responses to malaria and other inflammatory diseases is warranted.

Osteoprotegerin Is Essential for the Development of Endothelial Dysfunction Induced by Angiotensin II in Mice

Opinions on the effects of osteoprotegerin (OPG) have evolved over the years from a protein protecting the vasculature from calcification to a cardiovascular risk factor contributing to inflammation within the vascular wall. Nowadays, the link between OPG and angiotensin II (Ang II) appears to be particularly important. In this study, the endothelial function was investigated in OPG-knockout mice (B6.129.S4-OPG, OPG-) and wild-type (C57BL/6J, OPG+) mice under basic conditions and after Ang II exposure by assessing the endothelium-dependent diastolic response of aortic rings to acetylcholine in vitro. A further aim of the study was to compare the effect of Ang II on the expression of cytokines in the aortic wall of both groups of mice. Our study shows that rings from OPG- mice had their normal endothelial function preserved after incubation with Ang II, whereas those from OPG+ mice showed significant endothelial dysfunction. We conclude that the absence of OPG, although associated with a pro-inflammatory cytokine profile in the vascular wall, simultaneously protects against Ang II-induced increases in pro-inflammatory cytokines in the murine vascular wall. Our study also demonstrates that the absence of OPG can result in a decrease in the concentration of pro-inflammatory cytokines in the vascular wall after Ang II exposure. The presence of OPG is therefore crucial for the development of Ang II-induced inflammation in the vascular wall and for the development of Ang II-induced endothelial dysfunction.

Serum osteoprotegerin and its gene polymorphisms in patients with Takayasu's arteritis: a bicentric cross-sectional study

INTRODUCTION

Takayasu's arteritis (TAK) patients are at an elevated risk of metabolic syndrome and cardiovascular diseases (CVD). Currently, there are no well-validated biomarkers to assess this risk in this population. Previous research in different cohorts has linked serum levels of osteoprotegerin (OPG) and its polymorphisms to accelerated atherosclerosis and a marker of poor prognosis in CVD. Thus, we assessed this protein as a potential biomarker of CVD in TAK patients.

OBJECTIVES

To evaluate the serum levels of OPG and its SNPs (single nucleotide polymorphisms) in TAK patients and healthy controls, and to associate these parameters with clinical data.

METHODS

This bicentric cross-sectional study included TAK patients who were compared with healthy individuals (control group). The serum levels of OPG and the frequency of OPG SNPs [1181G > C (rs2073618), 245 A > C (rs3134069), 163T > C (rs3102735), and 209 C > T (rs3134070)] were compared between the both groups and associated with clinical data.

RESULTS

In total, 101 TAK patients and 93 controls were included in the study. The serum levels of OPG (3.8 ± 1.9 vs. 4.3 ± 1.8pmol/L, respectively; P = 0.059), and its four polymorphisms were comparable between both groups. In an additional analysis of only TAK patients, serum OPG levels and its four genes were not associated with any CVD parameters, except for higher OPG levels among patients without dyslipidemia.

CONCLUSION

No significant differences were observed in serum OPG levels or in the genotype frequencies of OPG SNPs between the patient and control groups. Similarly, no correlation was found between laboratory parameters and clinical data on CVD risk in TAK patients.

Pathological progression of osteoarthritis: a perspective on subchondral bone

Osteoarthritis (OA) is a degenerative bone disease associated with aging. The rising global aging population has led to a surge in OA cases, thereby imposing a significant socioeconomic burden. Researchers have been keenly investigating the mechanisms underlying OA. Previous studies have suggested that the disease starts with synovial inflammation and hyperplasia, advancing toward cartilage degradation. Ultimately, subchondral-bone collapse, sclerosis, and osteophyte formation occur. This progression is deemed as "top to bottom." However, recent research is challenging this perspective by indicating that initial changes occur in subchondral bone, precipitating cartilage breakdown. In this review, we elucidate the epidemiology of OA and present an in-depth overview of the subchondral bone's physiological state, functions, and the varied pathological shifts during OA progression. We also introduce the role of multifunctional signal pathways (including osteoprotegerin (OPG)/receptor activator of nuclear factor-kappa B ligand (RANKL)/receptor activator of nuclear factor-kappa B (RANK), and chemokine (CXC motif) ligand 12 (CXCL12)/CXC motif chemokine receptor 4 (CXCR4)) in the pathology of subchondral bone and their role in the "bottom-up" progression of OA. Using vivid pattern maps and clinical images, this review highlights the crucial role of subchondral bone in driving OA progression, illuminating its interplay with the condition.

History of fragility fracture is associated with cardiovascular mortality in hemodialysis patients: the Q-Cohort study

INTRODUCTION

In patients undergoing dialysis, major bone fracture is associated with a high risk of mortality, including death of cardiovascular (CV) origin. In the present study, we aimed to determine whether a history of fragility fracture is a predictor of CV death in patients undergoing hemodialysis with long-term follow-up.

MATERIALS AND METHODS

In total, 3499 patients undergoing hemodialysis were analyzed for 10 years. We evaluated the history of fragility fracture in each patient at enrollment. The primary outcome was CV death. A Cox proportional hazard model and a competing risk approach were applied to determine the association between a history of fragility fracture and CV death.

RESULTS

A total of 346 patients had a history of fragility fracture at enrollment. During a median follow-up of 8.8 years, 1730 (49.4%) patients died. Among them, 621 patients experienced CV death. Multivariable Cox analyses after adjustment for confounding variables showed that a history of fragility fracture was associated with CV death (hazard ratio, 1.47; 95% confidence interval, 1.16-1.85). In the Fine-Gray regression model, a history of fragility fracture was an independent risk factor for CV death (subdistribution hazard ratio, 1.36; 95% confidence interval, 1.07-1.72).

CONCLUSION

In a large cohort of patients undergoing hemodialysis, a history of fragility fracture was an independent predictor of CV death.

Exploring the potential mechanism of Heng-Gu-Gu-Shang-Yu-He-Ji therapy for osteoporosis based on network pharmacology and transcriptomics

ETHNOPHARMACOLOGICAL RELEVANCE

Heng-Gu-Gu-Shang-Yu-He-Ji (Osteoking, OK) is a well-known formula for fracture therapy. In clinic, OK is effective in treating fractures while alleviating osteoporosis (OP) symptoms. However, active components of OK and the associated molecular mechanisms remain not fully elucidated.

AIM OF THE STUDY

This study aims to systematically evaluate the anti-osteoporosis efficacy of OK and for the first time combine network pharmacology with high-throughput whole gene transcriptome sequencing to study its underlying mechanism.

MATERIALS AND METHODS

In this study, the osteoporosis model was established by the castration of both ovaries. The level of serum bone turnover factor was detected by enzyme-linked immunosorbent assay. Micro-CT and HE staining were used to observe the changes of bone histopathology, and nano-indentation technique was used to detect the biomechanical properties of rat bone. The main active Chemical components of OK were identified using UPLC-DAD. Efficacy verification and mechanism exploration were conducted by network pharmacology, molecular docking, whole gene transcriptomics and in vivo experiments.

RESULTS

In our study, OK significantly improved bone microarchitecture and bone biomechanical parameters in OVX rats, reduced osteoclast indexes such as C-telopeptide of type I collage (CTX-I) and increased Osteoprotegerin (OPG)/Receptor activator of NF-κB ligand (RANKL) levels. Mechanistically, PI3K/AKT pathway was a common pathway for genome enrichment analysis (KEGG) of both network pharmacology and RNA-seq studies. G protein-β-like protein (GβL), Ribosomal-protein S6 kinase homolog 2 (S6K2), and Phosphoinositide 3-kinase (PI3K) appeared differentially expression in the PI3K-AKT signaling pathway. These results were also confirmed by qRT-PCR and immunohistochemistry.

CONCLUSIONS

OK may be used to treat osteoporosis, at least partly by activating PI3K/AKT/mTORC1 signaling pathway.

[Biomarkers of Inflammation in Predicting the Outcomes of Heart Failure of Ischemic Etiology: the Results of Factor Analysis]

AIM

To study the prognostic significance of inflammatory biomarkers in patients with chronic heart failure (CHF) and stenotic multivessel coronary atherosclerosis, with determination of the biomarker separate set that reflects subclinical inflammation and is associated with the development of cardiovascular complications during prospective observation.

MATERIAL AND METHODS

A prospective observational study was conducted that included 80 patients with CHF and ischemic heart disease who were scheduled for coronary artery bypass grafting (CABG) during their current hospitalization. In addition to routine clinical laboratory tests, coagulation parameters were evaluated and the following inflammatory biomarkers were determined: neutrophil gelatinase-associated lipocalin (NGAL), growth/differentiation factor 15 (GDF-15), fibroblast growth factor 23 (FGF-23), transforming growth factor beta-1 (TGF-β1), and high-sensitivity C-reactive protein. Also, the calculated neutrophil-to-lymphocyte ratio (N LR) was included in the analysis. Follow-up duration was at least 12 months (median 16 [13, 22] months). Statistical analysis of the data was performed with the IBM SPSS Statistics 21 software.

RESULTS

The study presented results of a factor analysis of 10 inflammatory biomarkers in patients who were scheduled for CABG. One of the factors identified by the analysis included the levels of NGAL and GDF-15, N LR, and the level of fibrinogen in the blood in CHF patients with stenotic coronary atherosclerosis and was significantly associated with the death rate during prospective observation. Furthermore, this association remained significant even after adjustments for age, glomerular filtration rate, severity of heart and coronary insufficiency, and the presence of diabetes mellitus.

CONCLUSION

In patients with CHF and stenotic coronary atherosclerosis, a set of inflammatory markers, including blood NGAL, GDF-15, N LR, and fibrinogen, can be combined into one factor reflecting subclinical inflammation. The value of this factor can be used to predict cardiovascular death in the long term after surgical myocardial revascularization.

Circulating osteoprotegerin levels and cardiovascular outcomes in patients with pre-dialysis chronic kidney disease: results from the KNOW-CKD study

While the relationship between circulating osteoprotegerin (OPG) and cardiovascular events is well-established in the general population, its association with cardiovascular risks in chronic kidney disease (CKD) patients remains less robust. This study hypothesized that elevated circulating OPG levels might be associated with an increased risk of major adverse cardiac events (MACE) in CKD patients, a total of 2,109 patients with CKD stages 1 through pre-dialysis 5 from the KNOW-CKD cohort were categorized into quartiles based on serum OPG levels. The primary outcome of the study was 3-point MACE, defined as a composite of nonfatal myocardial infarction, nonfatal stroke, or cardiac death. The median follow-up duration was 7.9 years. The cumulative incidence of 3-point MACE significantly varied across serum OPG levels in Kaplan-Meier curve analysis (P < 0.001, log-rank test), with the highest incidence observed in the 4th quartile. Cox regression analysis indicated that, relative to the 1st quartile, the risk of 3-point MACE was significantly higher in the 3rd (adjusted hazard ratio 2.901, 95% confidence interval 1.009 to 8.341) and the 4th quartiles (adjusted hazard ratio 4.347, 95% confidence interval 1.410 to 13.395). In conclusion, elevated circulating OPG levels are associated with adverse cardiovascular outcomes in pre-dialysis CKD patients.

The Role of the Receptor Activator of Nuclear Factor Kappa-B Ligand/Osteoprotegerin Ratio in Vascular Diseases: A Therapeutic Approach

Cardiovascular and bone diseases contribute independently to mortality and global health. The exact mechanisms involved in the pathophysiology shared between bone and vascular diseases are not well defined. Endothelial cells and osteoblasts communicate during osteogenesis, thus establishing a connection between angiogenesis and osteogenesis. One shared mechanism may involve osteoprotegerin (OPG) and its ligand Receptor Activator of NF-κB Ligand (RANKL). The RANKL/OPG ratio is an important modulator for the skeletal, immunological, and vascular systems. OPG levels are elevated due to either osteogenic causes or inflammatory responses in the vasculature. The data obtained from clinical and in vitro studies support the role of the RANKL/OPG ratio as a potential marker for the progression of endothelial damage. Therefore, determining the therapeutic approaches for the targeting RANKL/OPG ratio and evaluating its usage as a biomarker in cardiovascular and bone pathophysiology are needed. By integrating the protective and disease-causing role of OPG with its ligand, this review outlines the role of the RANKL/OPG ratio at the molecular level. We also consider targeted therapeutic approaches.

Effects of Aging on Osteosynthesis at Bone-Implant Interfaces

Joint replacement is a common surgery and is predominantly utilized for treatment of osteoarthritis in the aging population. The longevity of many of these implants depends on bony ingrowth. Here, we provide an overview of current techniques in osteogenesis (inducing bone growth onto an implant), which is affected by aging and inflammation. In this review we cover the biologic underpinnings of these processes as well as the clinical applications. Overall, aging has a significant effect at the cellular and macroscopic level that impacts osteosynthesis at bone-metal interfaces after joint arthroplasty; potential solutions include targeting prolonged inflammation, preventing microbial adhesion, and enhancing osteoinductive and osteoconductive properties.

Antiosteoporosis medications and cardiovascular disease: a population-based nationwide nested case-control study

Purpose: Patients with osteoporosis are at an increased risk of cardiovascular disease (CVD). Several antiosteoporosis medications have been demonstrated with the benefit of preventing osteoporosis. Our aim is to assess the CVD risks associated with antiosteoporosis medications using the National Health Insurance Research Database in Taiwan between 2000 and 2016. Methods: Among 41,102 patients of 40+ years old with newly diagnosed osteoporosis, 69.1% (N = 28,387) of patients were included in the user cohort of antiosteoporosis medicines, of whom 13, 472 developed CVD by the end of 2016, while 14,915 did not. Using the nested case-control analysis in the user cohort (88.0% women and 77.4% elderly), we applied conditional logistic regression to estimate odds ratios (ORs) of eight types of CVD for the users of denosumab, bisphosphonate, teriparatide, and hormone replacement therapy (HRT). Results: The adjusted ORs of overall CVDs were 0.13 (95% CI: 0.12-0.15) for denosumab users, 0.52 (95% CI: 0.45-0.61) for teriparatide users, and 0.80 (95% CI: 0.76-0.85) for bisphosphonate users. The HRT users were at higher odds of coronary artery and peripheral artery diseases, heart failure, pulmonary embolism, and deep vein thrombosis. Conclusion: Denosumab, teriparatide, and bisphosphonate may have more protective effects against CVD than hormone therapy. Physicians may take subsequent cardiovascular risks into account when choosing an adequate antiosteoporosis medication for patients with osteoporosis.

Serum Osteoprotegerin Levels and the Vascular Reactivity Index in Patients with Hypertension

Background and Objectives: Osteoprotegerin (OPG), a soluble glycoprotein found in serum, has been associated with both the presence and severity of atherosclerosis. OPG is regarded as the mediator in the process of vascular endothelial dysfunction. Impaired endothelial function has an intimate link with hypertension (HTN) and is associated with significant morbidity and mortality. This study was to investigate the connection between OPG and endothelial dysfunction in patients having HTN. Materials and Methods: There are 102 patients with HTN included. For the purpose of determining the levels of OPG, a commercial enzyme-linked immunosorbent test kit was applied. The vascular reactivity index (VRI), which is assessed via the digital thermal monitoring, provides information on endothelial function. Results: Ten patients with HTN (9.8%) were classified as having poor vascular reactivity (VRI < 1.0), 46 HTN patients (45.1%) as having intermediate vascular reactivity (1.0 ≤ VRI < 2.0), and 46 HTN patients (45.1%) were classified as having high vascular reactivity (VRI ≥ 2.0). A greater serum OPG level (p < 0.001) and older age (p = 0.022) were linked to impaired vascular reactivity. The estimated glomerular filtration rate (r = 0.196, p = 0.048) was positively correlated with VRI values in hypertensive participants, while advanced age (r = -0.222, p = 0.025) and the log-transformed OPG level (log-OPG, r = -0.357, p < 0.001) were negatively correlated with VRI. Serum log-OPG level was shown to be strongly and independently correlated with VRI values in HTN individuals after multivariable forward stepwise linear regression analysis (β = -0.357, adjusted R2 change = 0.119, p < 0.001). Conclusions: In patients with HTN, serum OPG levels were adversely correlated with VRI and probably had a role in endothelial dysfunction.

RANKL inhibition: a new target of treating diabetes mellitus?

Accumulating evidence demonstrates the link between glucose and bone metabolism. The receptor activator of nuclear factor-kB ligand (RANKL)/the receptor activator of NF-κB (RANK)/osteoprotegerin (OPG) axis is an essential signaling axis maintaining the balance between bone resorption and bone formation. In recent years, it has been found that RANKL and RANK are distributed not only in bone but also in the liver, muscle, adipose tissue, pancreas, and other tissues that may influence glucose metabolism. Some scholars have suggested that the blockage of the RANKL signaling may protect islet β-cell function and prevent diabetes; simultaneously, there also exist different views that RANKL can improve insulin resistance through inducing the beige adipocyte differentiation and increase energy expenditure. Currently, the results of the regulatory effect on glucose metabolism of RANKL remain conflicting. Denosumab (Dmab), a fully human monoclonal antibody that can bind to RANKL and prevent osteoclast formation, is a commonly used antiosteoporosis drug. Recent basic studies have found that Dmab seems to regulate glucose homeostasis and β-cell function in humanized mice or in vitro human β-cell models. Besides, some clinical data have also reported the glucometabolic effects of Dmab, however, with limited and inconsistent results. This review mainly describes the impact of the RANKL signaling pathway on glucose metabolism and summarizes clinical evidence that links Dmab and DM to seek a new therapeutic strategy for diabetes.

Osteoprotegerin deficiency aggravates methionine-choline-deficient diet-induced nonalcoholic steatohepatitis in mice

Clinical studies have shown that osteoprotegerin (OPG) is reduced in patients with nonalcoholic steatohepatitis (NASH), but the underlying mechanisms are unclear. The current study focuses on the role of OPG in the NASH pathogenesis. OPG knockout mice and wild-type control mice fed a methionine choline-deficient diet (MCD) for 4 weeks resulted in an animal model of NASH. Measurement of triglycerides (TG) in serum and liver to assess steatosis. Hematoxylin eosin (HE), Sirius Red and Masson staining were used to assess the liver damage. Transcriptome sequencing analysis, qPCR and western blot were to analyze changes in lipid metabolism and inflammation-related indicators in the liver. In vivo knockout of OPG resulted in a reduction of TG levels in the liver and a significant increase in serum ALT and AST. The expression of inflammatory factors and fibrosis genes was significantly upregulated in the livers of OPG knockout mice. Transcriptome sequencing analysis showed that OPG knockout significantly enhanced MCD diet-induced activation of the mitogen-activated protein kinase (MAPK) signaling pathway. Mechanistically, OPG may inhibit MAPK signaling pathway activity by upregulating the expression of dual specificity phosphatase 14 (DUSP14), thereby reducing inflammatory injury. OPG could regulate the activity of the MAPK signaling pathway via DUSP14, thus regulating the expression of some inflammatory factors in NASH, it may be a promising target for the treatment of NASH.

Secukinumab and Black Garlic Downregulate OPG/RANK/RANKL Axis and Devitalize Myocardial Interstitial Fibrosis Induced by Sunitinib in Experimental Rats

Sunitinib has been associated with several cardiotoxic effects such as cardiac fibrosis. The present study was designed to explore the role of interleukin (IL)-17 in sunitinib-induced myocardial fibrosis (MF) in rats and whether its neutralization and/or administration of black garlic (BG), a form of fermented raw garlic (Allium sativum L.), could extenuate this adverse effect. Male Wistar albino rats received sunitinib (25 mg/kg three times a week, orally) and were co-treated with secukinumab (3 mg/kg, subcutaneously, three times total) and/or BG (300 mg/kg/day, orally) for four weeks. Administration of sunitinib induced significant increase in cardiac index, cardiac inflammatory markers, and cardiac dysfunction that were ameliorated by both secukinumab and BG, and to a preferable extent, with the combined treatment. Histological examination revealed disruption in the myocardial architecture and interstitial fibrosis in cardiac sections of the sunitinib group, which were reversed by both secukinumab and BG treatments. Both drugs and their co-administration restored normal cardiac functions, downregulated cardiac inflammatory cytokines, mainly IL-17 and NF-κB, along with increasing the MMP1/TIMP1 ratio. Additionally, they attenuated sunitinib-induced upregulation of the OPG/RANK/RANKL axis. These findings highlight another new mechanism through which sunitinib can induce interstitial MF. The current results propose that neutralizing IL-17 by secukinumab and/or supplementation with BG can be a promising therapeutic approach for ameliorating sunitinib-induced MF.

Causal effects for genetic variants of osteoprotegerin on the risk of acute myocardial infarction and coronary heart disease: A two-sample Mendelian randomization study

Although since the 1980s, the mortality of coronary heart disease(CHD) has obviously decreased due to the rise of coronary intervention, the mortality and disability of CHD were still high in some countries. Etiological studies of acute myocardial infarction(AMI) and CHD were extremely important. In this study, we used two-sample Mendelian randomization(TSMR) method to collect GWAS statistics of osteoprotegerin (OPG), AMI and CHD to reveal the causal relationship between OPG and these two diseases. In total, we identified 7 genetic variants associated with AMI and 7 genetic variants associated with CHD that were not found to be in linkage disequilibrium(LD; r ² < 0.001). Evidence of a positive effect of an OPG genetic susceptibility on AMI was discovered(IVW OR = 0.877; 95% CI = 0.787-0.977; p = 0.017; 7 SNPs) and CHD (IVW OR = 0.892; 95% CI = 0.803-0.991; p = 0.033; 7 SNPs). After removing the influence of rs1385492, we found that there was a correlation between OPG and AMI/CHD (AMI: weighted median OR = 0.818;95% CI = 0.724-0.950; p = 0.001; 6SNPs;CHD: weighted median OR = 0.842; 95% CI = 0.755-0.938; p = 1.893 × 10^-3; 6SNPs). The findings of our study indicated that OPG had a tight genetic causation association with MI or CHD. This genetic causal relationship presented us with fresh ideas for the etiology of AMI and CHD, which is an area of research that will continue in the future.

Osteoprotegerin Gene Polymorphisms Are Associated with Subclinical Atherosclerosis in the Mexican Mestizo Population

Subclinical atherosclerosis (SA) is the presence of coronary calcification in the absence of cardiovascular symptoms, and it usually progresses to atherosclerotic disease. Studies have shown an association of osteoprotegerin gene (OPG) variants with calcification process in cardiovascular diseases; however, to this day there are no studies that evaluate individuals in the asymptomatic stage of atherosclerotic disease. Therefore, the purpose of this study was to analyze the association of four genetic variants and haplotypes of the OPG gene with the development of SA, through TaqMan genotyping assays. We also aimed to identify potential response elements for transcription factors in these genetic variants. The study included 1413 asymptomatic participants (1041 were controls and 372 were individuals with SA). The rs3102735 polymorphism appeared as a protective marker (OR = 0.693; 95% CI = 0.493−0.974; pheterozygote = 0.035; OR = 0.699; 95% CI = 0.496−0.985; pcodominant 1 = 0.040) and two haplotypes were associated with SA, one as a decreased risk: GACC (OR = 0.641, 95% CI = 0.414−0.990, p = 0.045) and another as an increased risk: GACT (OR = 1.208, 95% CI = 1.020−1.431, p = 0.029). Our data suggest a lower risk of SA in rs3102735 C carriers in a representative sample of Mexican mestizo population.

The Roles of RANK/RANKL/OPG in Cardiac, Skeletal, and Smooth Muscles in Health and Disease

Although their physiology and functions are very different, bones, skeletal and smooth muscles, as well as the heart have the same embryonic origin. Skeletal muscles and bones interact with each other to enable breathing, kinesis, and the maintenance of posture. Often, muscle and bone tissues degenerate synchronously under various conditions such as cancers, space travel, aging, prolonged bed rest, and neuromuscular diseases. In addition, bone tissue, skeletal and smooth muscles, and the heart share common signaling pathways. The RANK/RANKL/OPG pathway, which is essential for bone homeostasis, is also implicated in various physiological processes such as sarcopenia, atherosclerosis, and cardiovascular diseases. Several studies have reported bone-skeletal muscle crosstalk through the RANK/RANKL/OPG pathway. This review will summarize the current evidence indicating that the RANK/RANKL/OPG pathway is involved in muscle function. First, we will briefly discuss the role this pathway plays in bone homeostasis. Then, we will present results from various sources indicating that it plays a physiopathological role in skeletal, smooth muscle, and cardiac functions. Understanding how the RANK/RANKL/OPG pathway interferes in several physiological disorders may lead to new therapeutic approaches aimed at protecting bones and other tissues with a single treatment.

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.

Paradoxical effects of osteoprotegerin on vascular function: inhibiting inflammation while promoting oxidative stress?

Osteoprotegerin (OPG), also known as osteoclastogenesis inhibitory factor or tumor necrosis factor receptor superfamily member 11B, is well known as a modulator of bone remodeling. The contribution of OPG to cardiovascular disease (CVD) has been suggested, but its molecular mechanism is complex and remains unclear. In the present study, Alves-Lopes et al. (Clin. Sci. (Lond.) (2021) 135(20): https://doi.org/10.1042/CS20210643) reported the critical role of syndecan-1 (SDC-1, also known as CD138), a surface protein part of the endothelial glycocalyx, in OPG-induced vascular dysfunction. The authors found that in endothelial cells (ECs), through SDC-1, OPG increased eNOS Thr495 phosphorylation, thereby inhibiting eNOS activity. Furthermore, the OPG-SDC-1 interaction increased reactive oxygen species (ROS) production through NOX1/4 activation. Both the reduced eNOS activity and induced ROS production inhibited NO production and impaired EC function. In vascular smooth muscle cells (VSMCs), the OPG-SDC-1 interaction increased ROS production through NOX1/4 activation, subsequently increased MLC phosphorylation-mediated Rho kinase-MYPT1 regulation, leading to increased vascular contraction. Ultilizing wire myography and mechanistic studies, the authors nicely provide the evidence that SDC-1 plays a crucial role in OPG-induced vascular dysfunction. As we mentioned above, the molecular mechanism and roles of OPG in cardiovascular system are complex and somewhat confusing. In this commentary, we briefly summarize the OPG-mediated signaling pathways in cardiovascular system.

The Role of SIRT3 in the Osteoporosis

SIRT3 is an NAD⁺-dependent deacetylase in the mitochondria with an extensive ability to regulate mitochondrial morphology and function. It has been reported that SIRT3 participates in the occurrence and development of many aging-related diseases. Osteoporosis is a common aging-related disease characterized by decreased bone mass and fragility fractures, which has caused a huge burden on society. Current research shows that SIRT3 is involved in the physiological processes of senescence of bone marrow mesenchymal stem cells (BMSCs), differentiation of BMSCs and osteoclasts. However, the specific effects and mechanisms of SIRT3 in osteoporosis are not clear. In the current review, we elaborated on the physiological functions of SIRT3, the cell types involved in bone remodeling, and the role of SIRT3 in osteoporosis. Furthermore, it also provided a theoretical basis for SIRT3 as a therapeutic target for osteoporosis.

Case report: Denosumab-associated acute heart failure in patients with cardiorenal insufficiency

Denosumab is a pivotal treatment for postmenopausal women with osteoporosis. Although its clinical use is generally well tolerated by patients, denosumab in patients with renal insufficiency may increase the risk of hypocalcemia. Thus, we have to consider the population of denosumab in the treatment of osteoporosis and preventive measures for related complications. In a patient with cardiorenal insufficiency, we reported a case of denosumab-induced hypocalcemia complicated by acute left heart failure due to delayed administration of active vitamin D and calcium supplements. The patient's symptoms did not improve after anti-heart failure treatment. However, after adequate calcium and vitamin D supplementation subsequently, the patient's symptoms of heart failure were rapidly relieved, and the serum calcium level returned to normal within three weeks. Therefore, our case showed that the application of denosumab in patients requires assessment of cardiac and renal function, timely calcium and vitamin D supplementation, and enhanced monitoring of serum calcium levels to prevent acute left heart failure induced by denosumab-related hypocalcemia.

Skeletal consequences of heart failure

Heart failure (HF) is a prevalent clinical syndrome that causes significant physical limitations. Osteoporosis is also an important cause of loss of functionality, and it mainly affects women. There are several reports linking HF and osteoporosis, and both share risk factors. Most of the data available so far point to bone fragility as a consequence of HF, and several mechanisms have been identified to explain this relationship. Among the proposed pathophysiological mechanisms are the hyperactivation of the renin-angiotensin-aldosterone system and the increase in parathyroid hormone, functional limitation, production of inflammatory mediators and the use of drugs for HF. The role of osteoprotegerin has gained attention owing to its cardiovascular and skeletal effects, its observed deficiency during the postmenopausal period along with its compensatory increases in HF and severe osteoporosis. The objective of this review was to perform a literature search for the main evidence on skeletal impairment in HF, with emphasis on women. As for epidemiological studies, we selected data from 3 meta-analyses and 20 individual observational studies, which together showed the interrelationship between the two clinical conditions in terms of both decreased bone density and increased fracture risk. In conclusion, HF and osteoporosis are interrelated conditions mediated by complex pathophysiological mechanisms which may be more relevant for postmenopausal women, considered to be a vulnerable population for both cardiovascular diseases and bone fragility.