The regulation of valvular and vascular sclerosis by osteogenic morphogens

Prevalence and impact of diabetes in patients with valvular heart disease

This study aimed to investigate the prevalence of diabetes in valvular heart disease (VHD), as well as the relationship of diabetes with severity of valvular lesions and clinical outcome. A total of 11,862 patients with significant (≥moderate) VHD from the China Valvular Heart Disease study were included in the analysis. The primary outcome was the composite of all-cause death, hospitalization for heart failure, and myocardial infarction during two-year follow-up. The prevalence of diabetes was 14.5% (1,721/11,862) in VHD. After adjusting for patients' demographics, diabetes was associated with a significantly lower risk of severe valvular lesion in aortic regurgitation and mitral regurgitation (MR). In multivariable analysis, diabetes was identified as an independent predictor of two-year outcome in patients with MR (hazard ratio: 1.345, 95% confidence interval: 1.069-1.692, p = 0.011). More efforts should be made to enhance our understanding and improve outcomes of concomitant VHD and diabetes.

Moscatilin inhibits vascular calcification by activating IL13RA2-dependent inhibition of STAT3 and attenuating the WNT3/β-catenin signalling pathway

INTRODUCTION

Vascular calcification, a devastating vascular complication accompanying atherosclerotic cardiovascular disease and chronic kidney disease, increases the incidence of adverse cardiovascular events and compromises the efficacy of vascular interventions. However, effective therapeutic drugs and treatments to delay or prevent vascular calcification are lacking.

OBJECTIVES

This study was designed to test the therapeutic effects and mechanism of Moscatilin (also known as dendrophenol) from Dendrobium huoshanense (an eminent traditional Chinese medicine) in suppressing vascular calcification in vitro, ex vivo and in vivo.

METHODS

Male C57BL/6J mice (25-week-old) were subjected to nicotine and vitamin D3 (VD3) treatment to induce vascular calcification. In vitro, we established the cellular model of osteogenesis of human aortic smooth muscle cells (HASMCs) under phosphate conditions.

RESULTS

By utilizing an in-house drug screening strategy, we identified Moscatilin as a new naturally-occurring chemical entity to reduce HASMC calcium accumulation. The protective effects of Moscatilin against vascular calcification were verified in cultured HASMCs. Unbiased transcriptional profiling analysis and cellular thermal shift assay suggested that Moscatilin suppresses vascular calcification via binding to interleukin 13 receptor subunit A2 (IL13RA2) and augmenting its expression. Furthermore, IL13RA2 was reduced during HASMC osteogenesis, thus promoting the secretion of inflammatory factors via STAT3. We further validated the participation of Moscatilin-inhibited vascular calcification by the classical WNT/β-catenin pathway, among which WNT3 played a key role in this process. Moscatilin mitigated the crosstalk between WNT3/β-catenin and IL13RA2/STAT3 to reduce osteogenic differentiation of HASMCs.

CONCLUSION

This study supports the potential of Moscatilin as a new naturally-occurring candidate drug for treating vascular calcification via regulating the IL13RA2/STAT3 and WNT3/β-catenin signalling pathways.

Exploring molecular profiles of calcification in aortic vascular smooth muscle cells and aortic valvular interstitial cells

Cardiovascular calcification can occur in vascular and valvular structures and is commonly associated with calcium deposition and tissue mineralization leading to stiffness and dysfunction. Patients with chronic kidney disease and associated hyperphosphatemia have an elevated risk for coronary artery calcification (CAC) and calcific aortic valve disease (CAVD). However, there is mounting evidence to suggest that the susceptibility and pathobiology of calcification in these two cardiovascular structures may be different, yet clinically they are similarly treated. To better understand diversity in molecular and cellular processes that underlie hyperphosphatemia-induced calcification in vascular and valvular structures, we exposed aortic vascular smooth muscle cells (AVSMCs) and aortic valve interstitial cells (AVICs) to high (2.5 mM) phosphate (Ph) conditions in vitro, and examined cell-specific responses. To further identify hyperphosphatemic-specific responses, parallel studies were performed using osteogenic media (OM) as an alternative calcific stimulus. Consistent with clinical observations made by others, we show that AVSMCs are more susceptible to calcification than AVICs. In addition, bulk RNA-sequencing reveals that AVSMCs and AVICs activate robust ossification-programs in response to high phosphate or OM treatments, however, the signaling pathways, cellular processes and osteogenic-associated markers involved are cell- and treatment-specific. For example, compared to VSMCs, VIC-mediated calcification involves biological processes related to osteo-chondro differentiation and down regulation of 'actin cytoskeleton'-related genes, that are not observed in VSMCs. Furthermore, hyperphosphatemic-induced calcification in AVICs and AVSMCs is independent of P13K signaling, which plays a role in OM-treated cells. Together, this study provides a wealth of information suggesting that the pathogenesis of cardiovascular calcifications is significantly more diverse than previously appreciated.

Kalkitoxin attenuates calcification of vascular smooth muscle cells via RUNX-2 signaling pathways

BACKGROUND

Kalkitoxin (KT) is an active lipopeptide isolated from the cyanobacterium Lyngbya majuscula found in the bed of the coral reef. Although KT suppresses cell division and inflammation, KT's mechanism of action in vascular smooth muscle cells (VSMCs) is unidentified. Therefore, our main aim was to investigate the impact of KT on vascular calcification for the treatment of cardiovascular disease.

OBJECTIVES

Using diverse calcification media, we studied the effect of KT on VSMC calcification and the underlying mechanism of this effect.

METHODS

VSMC was isolated from the 6 weeks ICR mice. Then VSMCs were treated with different concentrations of KT to check the cell viability. Alizarin red and von Kossa staining were carried out to examine the calcium deposition on VSMC. Thoracic aorta of 6 weeks mice were taken and treated with different concentrations of KT, and H and E staining was performed. Real-time polymerase chain reaction and western blot were performed to examine KT's effect on VSMC mineralization. Calcium deposition on VSMC was examined with a calcium deposition quantification kit.

RESULTS

Calcium deposition, Alizarin red, and von Kossa staining revealed that KT reduced inorganic phosphate-induced calcification phenotypes. KT also reduced Ca++-induced calcification by inhibiting genes that regulate osteoblast differentiation, such as runt-related transcription factor 2 (RUNX-2), SMAD family member 4, osterix, collagen 1α, and osteopontin. Also, KT repressed Ca2+-induced bone morphogenetic protein 2, RUNX-2, collagen 1α, osteoprotegerin, and smooth muscle actin protein expression. Likewise, Alizarin red and von Kossa staining showed that KT markedly decreased the calcification of ex vivo ring formation in the mouse thoracic aorta.

CONCLUSIONS

This experiment demonstrated that KT decreases vascular calcification and may be developed as a new therapeutic treatment for vascular calcification and arteriosclerosis.

Overexpression of microRNA-93-5p and microRNA-374a-5p Suppresses the Osteogenic Differentiation and Mineralization of Human Aortic Valvular Interstitial Cells Through the BMP2/Smad1/5/RUNX2 Signaling Pathway

ABSTRACT

Aortic valve calcification commonly occurs in patients with chronic kidney disease (CKD). However, the regulatory functions of microRNAs (miRNAs/miRs) in the osteogenic differentiation of human aortic valvular interstitial cells (hAVICs) in patients with CKD remain largely unknown. This study aimed to explore the functional role and underlying mechanisms of miR-93-5p and miR-374a-5p in the osteogenic differentiation of hAVICs. For this purpose, hAVICs calcification was induced with high-calcium/high-phosphate medium and the expression levels of miR-93-5p and miR-374a-5p were determined using bioinformatics assay. Alizarin red staining, intracellular calcium content, and alkaline phosphatase activity were used to evaluate calcification. The expression levels of bone morphogenetic protein-2 (BMP2), runt-related transcription factor 2 (Runx2), and phosphorylated (p)-Smad1/5 were detected by luciferase reporter assay, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), and western blot analysis. The results revealed that the expression levels of miR-93-5p and miR-374a-5p were significantly decreased in hAVICs in response to high-calcium/high-phosphate medium. The overexpression of miR-93-5p and miR-374a-5p effectively suppressed the high-calcium/high-phosphate-induced calcification and osteogenic differentiation makers. Mechanistically, the overexpression of miR-93-5p and miR-374a-5p inhibits osteogenic differentiation by regulating the BMP2/Smad1/5/Runx2 signaling pathway. Taken together, this study indicates that miR-93-5p and miR-374a-5p suppress the osteogenic differentiation of hAVICs associated with calcium-phosphate metabolic dyshomeostasis through the inhibition of the BMP2/Smad1/5/Runx2 signaling pathway.

Pathophysiology and Clinical Impacts of Chronic Kidney Disease on Coronary Artery Calcification

The global prevalence of chronic kidney disease (CKD) has increased in recent years. Adverse cardiovascular events have become the main cause of life-threatening events in patients with CKD, and vascular calcification is a risk factor for cardiovascular disease. Vascular calcification, especially coronary artery calcification, is more prevalent, severe, rapidly progressive, and harmful in patients with CKD. Some features and risk factors are unique to vascular calcification in patients with CKD; the formation of vascular calcification is not only influenced by the phenotypic transformation of vascular smooth muscle cells, but also by electrolyte and endocrine dysfunction, uremic toxin accumulation, and other novel factors. The study on the mechanism of vascular calcification in patients with renal insufficiency can provide a basis and new target for the prevention and treatment of this disease. This review aims to illustrate the impact of CKD on vascular calcification and to discuss the recent research data on the pathogenesis and factors involved in vascular calcification, mainly focusing on coronary artery calcification, in patients with CKD.

Free-aldehyde neutralized and oligohyaluronan loaded bovine pericardium with improved anti-calcification and endothelialization for bioprosthetic heart valves

The number of patients with valvular heart disease is increasing yearly, and valve replacement is the most effective treatment, during which bioprosthetic heart valves (BHVs) are the most widely used. Commercial BHVs are mainly prepared with glutaraldehyde (Glut) cross-linked bovine pericardial or porcine aortic valves, but the residual free aldehyde groups in these tissues can cause calcification and cytotoxicity. Moreover, insufficient glycosaminoglycans (GAGs) in tissues can further reduce biocompatibility and durability. However, the anti-calcification performance and biocompatibility might be improved by blocking the free aldehyde groups and increasing the GAGs content in Glut-crosslinked tissues. In our study, adipic dihydrazide (ADH) was used to neutralize the residual free aldehyde groups in tissues and provide sites to blind with oligohyaluronan (OHA) to increase the content of GAGs in tissues. The modified bovine pericardium was evaluated for its content of residual aldehyde groups, the amount of OHA loaded, physical/chemical characteristics, biomechanical properties, biocompatibility, and in vivo anticalcification assay and endothelialization effects in juvenile Sprague-Dawley rats. The results showed that ADH could completely neutralize the free aldehyde groups in the Glut-crosslinked bovine pericardium, the amount of OHA loaded increased and the cytotoxicity was reduced. Moreover, the in vivo results also showed that the level of calcification and inflammatory response in the modified pericardial tissue was significantly reduced in a rat subcutaneous implantation model, and the results from the rat abdominal aorta vascular patch repair model further demonstrated the improved capability of the modified pericardial tissues for endothelialization. Furthermore, more α-SMA+ smooth muscle cells and fewer CD68+ macrophages infiltrated in the neointima of the modified pericardial patch. In summary, blocking free-aldehydes and loading OHA improved the anti-calcification, anti-inflammation and endothelialization properties of Glut-crosslinked BHVs and in particularly, this modified strategy may be a promising candidate for the next-generation of BHVs.

Indoxyl-sulfate activation of the AhR- NF-κB pathway promotes interleukin-6 secretion and the subsequent osteogenic differentiation of human valvular interstitial cells from the aortic valve

BACKGROUND

Calcific aortic stenosis (CAS) is more prevalent, occurs earlier, progresses faster and has worse outcomes in patients with chronic kidney disease (CKD). The uremic toxin indoxyl sulfate (IS) is powerful predictor of cardiovascular mortality in these patients and a strong promoter of ectopic calcification whose role in CAS remains poorly studied. The objective of this study was to evaluate whether IS influences the mineralization of primary human valvular interstitial cells (hVICs) from the aortic valve.

METHODS

Primary hVICs were exposed to increasing concentrations of IS in osteogenic medium (OM). The hVICs' osteogenic transition was monitored by qRT-PCRs for BMP2 and RUNX2 mRNA. Cell mineralization was assayed using the o-cresolphthalein complexone method. Inflammation was assessed by monitoring NF-κB activation using Western blots as well as IL-1β, IL-6 and TNF-α secretion by ELISAs. Small interfering RNA (siRNA) approaches enabled us to determine which signaling pathways were involved.

RESULTS

Indoxyl-sulfate increased OM-induced hVICs osteogenic transition and calcification in a concentration-dependent manner. This effect was blocked by silencing the receptor for IS (the aryl hydrocarbon receptor, AhR). Exposure to IS promoted p65 phosphorylation, the blockade of which inhibited IS-induced mineralization. Exposure to IS promoted IL-6 secretion by hVICs, a phenomenon blocked by silencing AhR or p65. Incubation with an anti-IL-6 antibody neutralized IS's pro-calcific effects.

CONCLUSION

IS promotes hVIC mineralization through AhR-dependent activation of the NF-κB pathway and the subsequent release of IL-6. Further research should seek to determine whether targeting inflammatory pathways can reduce the onset and progression of CKD-related CAS.

Rho A/ROCK1 signaling-mediated metabolic reprogramming of valvular interstitial cells toward Warburg effect accelerates aortic valve calcification via AMPK/RUNX2 axis

The aberrant differentiation of valvular interstitial cells (VICs) to osteogenic lineages promotes calcified aortic valves disease (CAVD), partly activated by potentially destructive hemodynamic forces. These involve Rho A/ROCK1 signaling, a mechano-sensing pathway. However, how Rho A/ROCK1 signaling transduces mechanical signals into cellular responses and disrupts normal VIC homeostasis remain unclear. We examined Rho A/ROCK1 signaling in human aortic valves, and further detected how Rho A/ROCK1 signaling regulates mineralization in human VICs. Aortic valves (CAVD n = 22, normal control (NC) n = 12) from patients undergoing valve replacement were investigated. Immunostaining and western blotting analysis indicated that Rho A/ROCK1 signaling, as well as key transporters and enzymes involved in the Warburg effect, were markedly upregulated in human calcified aortic valves compared with those in the controls. In vitro, Rho A/ROCK1-induced calcification was confirmed as AMPK-dependent, via a mechanism involving metabolic reprogramming of human VICs to Warburg effect. Y-27632, a selective ROCK1 inhibitor, suppressed the Warburg effect, rescued AMPK activity and subsequently increased RUNX2 ubiquitin-proteasome degradation, leading to decreased RUNX2 protein accumulation in human VICs under pathological osteogenic stimulus. Rho A/ROCK1 signaling, which is elevated in human calcified aortic valves, plays a positive role in valvular calcification, partially through its ability to drive metabolic switching of VICs to the Warburg effect, leading to altered AMPK activity and RUNX2 protein accumulation. Thus, Rho A/ROCK1 signaling could be an important and unrecognized hub of destructive hemodynamics and cellular aerobic glycolysis that is essential to promote the CAVD process.

Association between Periodontitis and Aortic Calcification: A Cohort Study

The present study investigated the association between the presence of periodontitis and aortic calcification (AC) risk among Chinese adults. A total of 6059 individuals who underwent regular health check-ups and received a diagnosis of periodontitis between 2009 and 2016 were included. The outcome was AC, assessed by a chest low-dose spiral CT scan. Cox proportional hazards regression analysis was used to assess the association between periodontitis and AC risk after adjusting for several confounders. After a median follow-up period of 2.3 years (interquartile range: 1.03-4.97 years), 843 cases of AC were identified, with 532 (12.13%) and 311 (18.59%) patients in the non-periodontitis group and periodontitis group, respectively. Multivariate analyses demonstrated that, compared with those without periodontitis, the hazard ratio and 95% confidence interval for AC risk in participants with periodontitis was 1.18 (1.02-1.36) (P = .025) in the fully adjusted model. Stratified analyses showed that the positive relationship between periodontitis and AC was more evident in males and participants <65 years of age (p_interaction = .005 and .004, respectively). Our results show that the presence of periodontitis was positively associated with AC among Chinese adults, especially among males and younger participants.

Vascular smooth muscle cells in intimal hyperplasia, an update

Arterial occlusive disease is the leading cause of death in Western countries. Core contemporary therapies for this disease include angioplasties, stents, endarterectomies and bypass surgery. However, these treatments suffer from high failure rates due to re-occlusive vascular wall adaptations and restenosis. Restenosis following vascular surgery is largely due to intimal hyperplasia. Intimal hyperplasia develops in response to vessel injury, leading to inflammation, vascular smooth muscle cells dedifferentiation, migration, proliferation and secretion of extra-cellular matrix into the vessel's innermost layer or intima. In this review, we describe the current state of knowledge on the origin and mechanisms underlying the dysregulated proliferation of vascular smooth muscle cells in intimal hyperplasia, and we present the new avenues of research targeting VSMC phenotype and proliferation.

Repression of the antiporter SLC7A11/glutathione/glutathione peroxidase 4 axis drives ferroptosis of vascular smooth muscle cells to facilitate vascular calcification

Vascular calcification is a common pathologic condition in patients with chronic kidney disease (CKD). Cell death such as apoptosis plays a critical role in vascular calcification. Ferroptosis is a type of iron-catalyzed and regulated cell death resulting from excessive iron-dependent reactive oxygen species and lipid peroxidation. However, it is unclear whether ferroptosis of vascular smooth muscle cells (VSMCs) regulates vascular calcification in CKD. Our results showed that high calcium and phosphate concentrations induced ferroptosis in rat VSMCs in vitro. Inhibition of ferroptosis by ferrostatin-1 dose-dependently reduced mineral deposition in rat VSMCs under pro-osteogenic conditions, as indicated by alizarin red staining and quantification of calcium content. In addition, gene expression analysis revealed that ferrostatin-1 inhibited osteogenic differentiation of rat VSMCs. Similarly, ferrostatin-1 remarkably attenuated calcification of rat and human arterial rings ex vivo and aortic calcification in vitamin D₃-overloaded mice in vivo. Moreover, inhibition of ferroptosis by either ferrostatin-1 or deferoxamine attenuated aortic calcification in rats with CKD. Mechanistically, high calcium and phosphate downregulated expression of SLC7A11 (a cystine-glutamate antiporter), and reduced glutathione (GSH) content in VSMCs. Additionally, GSH depletion induced by erastin (a small molecule initiating ferroptotic cell death) significantly promoted calcification of VSMCs under pro-osteogenic conditions, whereas GSH supplement by N-acetylcysteine reduced calcification of VSMCs. Consistently, knockdown of SLC7A11 by siRNA markedly promoted VSMC calcification. Furthermore, high calcium and phosphate downregulated glutathione peroxidase 4 (GPX4) expression, and reduced glutathione peroxidase activity. Inhibition of GPX4 by RSL3 promoted VSMC calcification. Thus, repression of the SLC7A11/GSH/GPX4 axis triggers ferroptosis of VSMCs to promote vascular calcification under CKD conditions, providing a novel targeting strategy for vascular calcification.

Azelastine a potent antihistamine agent, as hypolipidemic and modulator for aortic calcification in diabetic hyperlipidemic rats model

AIM

Our study aimed to illustrate the effect of the antihistaminic drug azelastine on aortic calcification in diabetic hyperlipidemic (DH) rats along with the underlying molecular mechanism.

METHODS

Twenty-four male albino Wistar rats were categorised into four groups. One group received normal rodent chow (normal group), while the other groups were rendered diabetic and hyperlipidemic; one received no drugs and served as a positive control while the other two groups received either azelastine (4 mg/kg) or 10-dehydrogingerdione (10 mg/kg) orally and daily for 8 weeks.

RESULTS

Azelastine significantly reduced blood glucose, HbA1c and serum ALP, OCN, downregulated apo B, improved the lipid profile (LDL-c decrease and HDL-c increase), attenuated calcium deposition and aortic calcification as compared to control group. 10-DHGD showed comparatively lower effect.

CONCLUSION

Anti-calcifying effect of azelastine might be related to upregulation of apo A (HDL-c) and downregulation of apo B mRNA expression indeed good modulator of aortic calcification.

IMPACT STATEMENT

Many studies have indicated that high-density lipoprotein-cholesterol (HDL-c) is inversely correlated with atherosclerotic plaque progression and could reduce cardiovascular disease risk. An anti-calcifying effect of HDL-c has been reported and targeting this lipoprotein may therefore be a valuable approach to vascular calcification control. Azelastine is a selective H1 antagonist that was identified to increase mRNA expression of apolipoprotein A. This encouraged us to investigate the effect of azelastine on lipid profile and markers of aortic calcification in DH rats. Our findings showed that azelastine ameliorated aortic calcification and increased apoA expression along with a decline in apo B. This may represent the underlying mechanism while the histopathological findings offered a significant support to the collected biochemical data.

Exosomes: mediators regulating the phenotypic transition of vascular smooth muscle cells in atherosclerosis

Cardiovascular disease is one of the leading causes of human mortality worldwide, mainly due to atherosclerosis (AS), and the phenotypic transition of vascular smooth muscle cells (VSMCs) is a key event in the development of AS. Exosomes contain a variety of specific nucleic acids and proteins that mediate intercellular communication. The role of exosomes in AS has attracted attention. This review uses the VSMC phenotypic transition in AS as the entry point, introduces the effect of exosomes on AS from different perspectives, and discusses the status quo, deficiencies, and potential future directions in this field to provide new ideas for clinical research and treatment of AS. Video Abstract.

Molecular mechanisms and effects of urocortin II on rat adventitial fibroblast calcification induced by calcified medium

The present study aimed to assess the role of urocortin II (UII) in the process of vascular calcification in vitro by using a calcification model, to detect the changes in the mRNA and protein levels of associated markers in rat adventitial fibroblasts (AFs) during their phenotypic transformation to osteoblast cellsto clarify the main signal transduction pathway of UII responsible for regulating vascular calcification and AF phenotypic transformation of osteoblast cells, and to prove that UII was an endogenous factor promoting vascular calcification, so as to provide an effective experimental basis for the clinical regulation of related diseases caused by vascular calcification. Finally, we successfully constructed the calcified cell model, found that UII was an endogenous substance regulating vascular calcification, regulated the vascular calcification by promoting apoptosis and inhibiting autophagy through up- and downregulated BAX and BCL-2/BECLIN 1 (BECN1) level, and the Wnt/β-catenin signaling pathway was involved.

Left-Sided Degenerative Valvular Heart Disease in Type 1 and Type 2 Diabetes

BACKGROUND

The role of diabetes in the development of valvular heart disease, and, in particular, the relation with risk factor control, has not been extensively studied.

METHODS

We included 715 143 patients with diabetes registered in the Swedish National Diabetes Register and compared them with 2 732 333 matched controls randomly selected from the general population. First, trends were analyzed with incidence rates and Cox regression, which was also used to assess diabetes as a risk factor compared with controls, and, second, separately in patients with diabetes according to the presence of 5 risk factors.

RESULTS

The incidence of valvular outcomes is increasing among patients with diabetes and the general population. In type 2 diabetes, systolic blood pressure, body mass index, and renal function were associated with valvular lesions. Hazard ratios for patients with type 2 diabetes who had nearly all risk factors within target ranges, compared with controls, were as follows: aortic stenosis 1.34 (95% CI, 1.31-1.38), aortic regurgitation 0.67 (95% CI, 0.64-0.70), mitral stenosis 1.95 (95% CI, 1.76-2.20), and mitral regurgitation 0.82 (95% CI, 0.79-0.85). Hazard ratios for patients with type 1 diabetes and nearly optimal risk factor control were as follows: aortic stenosis 2.01 (95% CI, 1.58-2.56), aortic regurgitation 0.63 (95% CI, 0.43-0.94), and mitral stenosis 3.47 (95% CI, 1.37-8.84). Excess risk in patients with type 2 diabetes for stenotic lesions showed hazard ratios for aortic stenosis 1.62 (95% CI, 1.59-1.65), mitral stenosis 2.28 (95% CI, 2.08-2.50), and excess risk in patients with type 1 diabetes showed hazard ratios of 2.59 (95% CI, 2.21-3.05) and 11.43 (95% CI, 6.18-21.15), respectively. Risk for aortic and mitral regurgitation was lower in type 2 diabetes: 0.81 (95% CI, 0.78-0.84) and 0.95 (95% CI, 0.92-0.98), respectively.

CONCLUSIONS

Individuals with type 1 and 2 diabetes have greater risk for stenotic lesions, whereas risk for valvular regurgitation was lower in patients with type 2 diabetes. Patients with well-controlled cardiovascular risk factors continued to display higher risk for valvular stenosis, without a clear stepwise decrease in risk between various degrees of risk factor control.

Cellular Crosstalk in the Vascular Wall Microenvironment: The Role of Exosomes in Vascular Calcification

Vascular calcification is prevalent in aging, diabetes, chronic kidney disease, cardiovascular disease, and certain genetic disorders. However, the pathogenesis of vascular calcification is not well-understood. It has been progressively recognized that vascular calcification depends on the bidirectional interactions between vascular cells and their microenvironment. Exosomes are an essential bridge to mediate crosstalk between cells and organisms, and thus they have attracted increased research attention in recent years. Accumulating evidence has indicated that exosomes play an important role in cardiovascular disease, especially in vascular calcification. In this review, we introduce vascular biology and focus on the crosstalk between the different vessel layers and how their interplay controls the process of vascular calcification.

PALMD regulates aortic valve calcification via altered glycolysis and NF-κB-mediated inflammation

Recent genome-wide association and transcriptome-wide association studies have identified an association between the PALMD locus, encoding palmdelphin, a protein involved in myoblast differentiation, and calcific aortic valve disease (CAVD). Nevertheless, the function and underlying mechanisms of PALMD in CAVD remain unclear. We herein investigated whether and how PALMD affects the pathogenesis of CAVD using clinical samples from CAVD patients and a human valve interstitial cell (hVIC) in vitro calcification model. We showed that PALMD was upregulated in calcified regions of human aortic valves and calcified hVICs. Furthermore, silencing of PALMD reduced hVIC in vitro calcification, osteogenic differentiation, and apoptosis, whereas overexpression of PALMD had the opposite effect. RNA-Seq of PALMD-depleted hVICs revealed that silencing of PALMD reduced glycolysis and nuclear factor-κB (NF-κB)–mediated inflammation in hVICs and attenuated tumor necrosis factor α–induced monocyte adhesion to hVICs. Having established the role of PALMD in hVIC glycolysis, we examined whether glycolysis itself could regulate hVIC osteogenic differentiation and inflammation. Intriguingly, the inhibition of PFKFB3-mediated glycolysis significantly attenuated osteogenic differentiation and inflammation of hVICs. However, silencing of PFKFB3 inhibited PALMD-induced hVIC inflammation, but not osteogenic differentiation. Finally, we showed that the overexpression of PALMD enhanced hVIC osteogenic differentiation and inflammation, as opposed to glycolysis, through the activation of NF-κB. The present study demonstrates that the genome-wide association– and transcriptome-wide association–identified CAVD risk gene PALMD may promote CAVD development through regulation of glycolysis and NF-κB–mediated inflammation. We propose that targeting PALMD-mediated glycolysis may represent a novel therapeutic strategy for treating CAVD.

Resveratrol ameliorates high-phosphate-induced VSMCs to osteoblast-like cells transdifferentiation and arterial medial calcification in CKD through regulating Wnt/β-catenin signaling

Vascular smooth muscle cells (VSMCs) to osteoblast-like cells transdifferentiation induced by high-phosphate is a crucial step in the development of arterial medial calcification (AMC) in patients with chronic kidney disease (CKD), and previous studies implicate Wnt/β-catenin signaling in osteogenic transdifferentiation of VSMCs and AMC. Given that resveratrol's ability to modulate Wnt/β-catenin signaling in other types of cell, we tested the effect of resveratrol on high-phosphate-induced osteogenic transdifferentiation of VSMCs and AMC in CKD. Resveratrol ameliorated AMC in rats with chronic renal failure and calcium deposition in aortic rings and VSMCs cultured in a high-phosphate environment. Resveratrol also diminished high-phosphate-induced osteogenic transdifferentiation of VSMCs in cultured aortic rings and VSMCs. In vitro, resveratrol attenuated the activation of β-catenin induced by high-phosphate and inhibited the expression of Runx2, a downstream effector of Wnt/β-catenin signaling during osteogenic transdifferentiation of VSMCs. Intriguingly, resveratrol inhibited high-phosphate-induced phosphorylation of LRP6 (Ser1490), but didn't inhibit Wnt3a-induced phosphorylation of LRP6 (Ser1490) and Runx2 expression. The expression of several Wnts was induced by high-phosphate, but the expression of Wnt7a, not Wnt2b and Wnt10a could be suppressed by resveratrol. In addition, the expression of both porcupine and wntless, two obligatory proteins for Wnt secretion, was induced by high-phosphate in cultured aortic rings and VSMCs, which could be suppressed by resveratrol. In summary, these findings suggest that resveratrol possesses a vascular protective effect on retarding high-phosphate-induced osteogenic transdifferentiation of VSMCs and AMC in CKD by targeting Wnt/β-catenin signaling, which may, to a large extent, via impeding Wnt secretion.

Cardiac Calcifications: Phenotypes, Mechanisms, Clinical and Prognostic Implications

There is a growing interest in arterial and heart valve calcifications, as these contribute to cardiovascular outcome, and are leading predictors of cardiovascular and kidney diseases. Cardiovascular calcifications are often considered as one disease, but, in effect, they represent multifaced disorders, occurring in different milieus and biological phenotypes, following different pathways. Herein, we explore each different molecular process, its relative link with the specific clinical condition, and the current therapeutic approaches to counteract calcifications. Thus, first, we explore the peculiarities between vascular and valvular calcium deposition, as this occurs in different tissues, responds differently to shear stress, has specific etiology and time courses to calcification. Then, we differentiate the mechanisms and pathways leading to hyperphosphatemic calcification, typical of the media layer of the vessel and mainly related to chronic kidney diseases, to those of inflammation, typical of the intima vascular calcification, which predominantly occur in atherosclerotic vascular diseases. Finally, we examine calcifications secondary to rheumatic valve disease or other bacterial lesions and those occurring in autoimmune diseases. The underlying clinical conditions of each of the biological calcification phenotypes and the specific opportunities of therapeutic intervention are also considered and discussed.

Osteogenic Circulating Endothelial Progenitor Cells are Associated with Vascular Aging of the Large Arteries in Rheumatoid Arthritis

Background and Aim

Rheumatoid arthritis is associated with both abnormal bone metabolism and accelerated vascular aging but a mechanistic link was lacking. This study aims to investigate the role of osteocalcin (OCN)-expressing circulating endothelial progenitor cells (EPCs) in vascular aging, as determined by arterial calcifications in rheumatoid arthritis.

Methods

We performed flow cytometry studies in 145 consecutive patients with rheumatoid arthritis to determine osteogenic circulating levels of OCN-positive (OCN+) CD34+KDR+ and OCN+CD34+ versus conventional early EPC CD34+CD133+KDR+. Total calcium load of the thoracic aorta (ascending plus descending) and the carotid arteries were assessed by non-contrast computed tomography (CT) and contrast CT angiography.

Results

Osteogenic EPCs OCN+CD34+KDR+ (P = 0.002) and OCN+CD34+ (P = 0.001), together with clinical parameters of age, history of hypertension, systolic blood pressure, serum levels of triglycerides, HbA1c and creatinine, use of leflunomide and brachial-ankle pulse-wave velocity (all P < 0.05), were associated with the clustered presence of aortic and carotid calcification. Multivariable analyses revealed that circulating OCN+CD34+KDR+ (B = 14.4 [95% CI 4.0 to 24.8], P = 0.007) and OCN+CD34+ (B = 9.6 [95% CI 4.9 to 14.3], P < 0.001) remained independently associated with increased aortic calcium load. OCN+CD34+ EPC (B = 0.8 [95% CI 0.1 to 1.5], P = 0.023), but not OCN+CD34+KDR+ EPC (B = 1.2 [95% CI −0.2 to 2.6], P = 0.09), was further independently associated with carotid calcium load. In comparison, conventional early EPC CD34+CD133+KDR+ had no significant association with aortic or carotid calcium load (P = 0.46 and 0.88, respectively).

Conclusion

Circulating level of osteogenic EPC is associated with increased vascular aging in terms of calcification of the large arteries in patients with rheumatoid arthritis. The findings may suggest a role of the bone-vascular axis underlying vascular aging in rheumatic diseases. Further research is needed to characterize the mechanistic links and basis of these observations.

Bioinformatics and Machine Learning Methods to Identify FN1 as a Novel Biomarker of Aortic Valve Calcification

Aim

The purpose of this study was to identify potential diagnostic markers for aortic valve calcification (AVC) and to investigate the function of immune cell infiltration in this disease.

Methods

The AVC data sets were obtained from the Gene Expression Omnibus. The identification of differentially expressed genes (DEGs) and the performance of functional correlation analysis were carried out using the R software. To explore hub genes related to AVC, a protein–protein interaction network was created. Diagnostic markers for AVC were then screened and verified using the least absolute shrinkage and selection operator, logistic regression, support vector machine-recursive feature elimination algorithms, and hub genes. The infiltration of immune cells into AVC tissues was evaluated using CIBERSORT, and the correlation between diagnostic markers and infiltrating immune cells was analyzed. Finally, the Connectivity Map database was used to forecast the candidate small molecule drugs that might be used as prospective medications to treat AVC.

Results

A total of 337 DEGs were screened. The DEGs that were discovered were mostly related with atherosclerosis and arteriosclerotic cardiovascular disease, according to the analyses. Gene sets involved in the chemokine signaling pathway and cytokine–cytokine receptor interaction were differently active in AVC compared with control. As the diagnostic marker for AVC, fibronectin 1 (FN1) (area the curve = 0.958) was discovered. Immune cell infiltration analysis revealed that the AVC process may be mediated by naïve B cells, memory B cells, plasma cells, activated natural killer cells, monocytes, and macrophages M0. Additionally, FN1 expression was associated with memory B cells, M0 macrophages, activated mast cells, resting mast cells, monocytes, and activated natural killer cells. AVC may be reversed with the use of yohimbic acid, the most promising small molecule discovered so far.

Conclusion

FN1 can be used as a diagnostic marker for AVC. It has been shown that immune cell infiltration is important in the onset and progression of AVC, which may benefit in the improvement of AVC diagnosis and treatment.

Unspliced XBP1 Counteracts β-catenin to Inhibit Vascular Calcification

Background: Vascular calcification is a prevalent complication in chronic kidney disease and contributes to increased cardiovascular morbidity and mortality. XBP1 (X-box binding protein 1), existing as the unspliced (XBP1u) and spliced (XBP1s) forms, is a key component of the endoplasmic reticulum stress involved in vascular diseases. However, whether XBP1u participates in the development of vascular calcification remains unclear. Methods: We aim to investigate the role of XBP1u in vascular calcification.XBP1u protein levels were reduced in high phosphate (Pi)-induced calcified vascular smooth muscle cells (VSMCs), calcified aortas from mice with adenine diet-induced chronic renal failure (CRF) and calcified radial arteries from CRF patients. Results: Inhibition of XBP1u rather than XBP1s upregulated in the expression of the osteogenic markers runt-related transcription factor 2 (Runx2) and msh homeobox2 (Msx2), and exacerbated high Pi-induced VSMC calcification, as verified by calcium deposition and Alizarin red S staining. In contrast, XBP1u overexpression in high Pi-induced VSMCs significantly inhibited osteogenic differentiation and calcification. Consistently, SMC-specific XBP1 deficiency in mice markedly aggravated the adenine diet- and 5/6 nephrectomy-induced vascular calcification compared with that in the control littermates. Further interactome analysis revealed that XBP1u bound directly to β-catenin, a key regulator of vascular calcification, via aa 205-230 in its C-terminal degradation domain. XBP1u interacted with β-catenin to promote its ubiquitin-proteasomal degradation and thus inhibited β-catenin/T-cell factor (TCF)-mediated Runx2 and Msx2 transcription. Knockdown of β-catenin abolished the effect of XBP1u deficiency on VSMC calcification, suggesting a β-catenin-mediated mechanism. Moreover, the degradation of β-catenin promoted by XBP1u was independent of glycogen synthase kinase 3β (GSK-3β)-involved destruction complex. Conclusions: Our study identified XBP1u as a novel endogenous inhibitor of vascular calcification by counteracting β-catenin and promoting its ubiquitin-proteasomal degradation, which represents a new regulatory pathway of β-catenin and a promising target for vascular calcification treatment.

Dextromethorphan Reduces Oxidative Stress and Inhibits Uremic Artery Calcification

Medial vascular calcification has emerged as a key factor contributing to cardiovascular mortality in patients with chronic kidney disease (CKD). Vascular smooth muscle cells (VSMCs) with osteogenic transdifferentiation play a role in vascular calcification. Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitors reduce reactive oxygen species (ROS) production and calcified-medium-induced calcification of VSMCs. This study investigates the effects of dextromethorphan (DXM), an NADPH oxidase inhibitor, on vascular calcification. We used in vitro and in vivo studies to evaluate the effect of DXM on artery changes in the presence of hyperphosphatemia. The anti-vascular calcification effect of DXM was tested in adenine-fed Wistar rats. High-phosphate medium induced ROS production and calcification of VSMCs. DXM significantly attenuated the increase in ROS production, the decrease in ATP, and mitochondria membrane potential during the calcified-medium-induced VSMC calcification process (p < 0.05). The protective effect of DXM in calcified-medium-induced VSMC calcification was not further increased by NADPH oxidase inhibitors, indicating that NADPH oxidase mediates the effect of DXM. Furthermore, DXM decreased aortic calcification in Wistar rats with CKD. Our results suggest that treatment with DXM can attenuate vascular oxidative stress and ameliorate vascular calcification.

Zwitterionic hydrogel-coated heart valves with improved endothelialization and anti-calcification properties

Valve replacement surgery is the golden standard for end-stage valvular disease due to the lack of self-repair ability. Currently, bioprosthetic heart valves (BHVs) crosslinked by glutaraldehyde (GA) have been the most popular choice in clinic, especially after the emerge of transcatheter aortic valve replacement (TAVR). Nevertheless, the lifespan of BHVs is limited due to severe calcification and deterioration. In this study, to improve the anti-calcification property of BHVs, decellularized heart valves were modified by methacrylic anhydride to introduce double bonds (MADHVs), and a hybrid hydrogel made of sulfobetaine methacrylate (SBMA) and methacrylated hyaluronic acid (MAHA) was then coated onto the surface of MADHVs. Followed by grafting of Arg-Glu-Asp-Val (REDV), an endothelial cell-affinity peptide, the BHVs with improved affinity to endothelial cell (SMHVs-REDV) was obtained. SMHVs-REDV exhibited excellent collagen stability, reliable mechanical property and superior hemocompatibility. Moreover, enhanced biocompatibility and endothelialization potential compared with GA-crosslinked BHVs were achieved. After subcutaneous implantation for 30 days, SMHVs-REDV showed significantly reduced immune response and calcification compared with GA-crosslinked BHVs. Overall, simultaneous endothelialization and anti-calcification can be realized by this strategy, which was supposed to be benefit for improving the main drawbacks for available commercial BHVs products.

Ginkgo Biloba Extract EGB761 Alleviates Warfarin-induced Aortic Valve Calcification Through the BMP2/Smad1/5/Runx2 Signaling Pathway

ABSTRACT

Calcific aortic valve disease is a common heart disease that contributes to increased cardiovascular morbidity and mortality. There is a lack of effective pharmaceutical therapy because its mechanisms are not yet fully known. Ginkgo biloba extract (EGB761) is reported to alleviate vascular calcification. However, whether EGB761 protects against aortic valve calcification, a disease whose pathogenesis shares many similarities with vascular calcification, and potential molecular mechanisms remain unknown. In this study, porcine aortic valve interstitial cell (pAVIC) calcification was induced by warfarin with or without the presence of EGB761. Immunostaining was performed to establish and characterize the pAVIC phenotype. Calcium deposition and calcium content were examined by Alizarin Red S staining and an intracellular calcium content assay. Alkaline phosphatase activity was detected by the p-nitrophenyl phosphate method. The expression levels of bone morphogenetic protein-2 (BMP2), Runt-related transcription factor 2 (Runx2), homeobox protein MSX-2, and phosphorylated (p)-Smad1/5 were detected by reverse transcription-quantitative polymerase chain reaction (PCR) and Western blot analysis. Consistent with these in vitro data, we also confirmed the suppression of in vivo calcification by EGB761 in the warfarin-induced C57/Bl6 mice. The results indicated that both pAVICs and aortic valves tissue of mice stimulated with warfarin showed increased calcium deposition and expression of osteogenic markers (alkaline phosphatase, BMP2, homeobox protein MSX-2, and Runx2) and promoted p-Smad1/5 translocation from the cytoplasm to the nucleus. The addition of EGB761 significantly inhibited p-Smad1/5 translocation from the cytoplasm to the nucleus, thus suppressing calcification. In conclusion, EGB761 could ameliorate warfarin-induced aortic valve calcification through the inhibition of the BMP2-medicated Smad1/5/Runx2 signaling pathway.

Arterial biomarkers in the evaluation, management and prognosis of aortic stenosis

Degenerative aortic valve stenosis is the most common primary valve disease and a significant cause of cardiovascular morbidity and mortality. In an era when new techniques for the management of aortic stenosis are gaining ground, the understanding of this disease is more important than ever to optimize treatment. So far, the focus has been placed on the assessment of the valve itself. However, the role that the arterial system plays in the pathogenesis and natural history of the disease needs to be further elucidated. Arteriosclerosis, when it coexists with a stenotic valve, augments the load posed on the left ventricle contributing to greater impairment of cardiovascular function. Arterial stiffness, a well-established predictor for cardiovascular disease and all-cause mortality, could play a role in the prognosis and quality of life of this population. Several studies using a variety of indices to assess arterial stiffness have tried to address the potential utility of arterial function assessment in the case of aortic stenosis. Importantly, reliable data identify a prognostic role of arterial biomarkers in aortic stenosis and stress their possible use to optimize timing and method of treatment. This review aims at summarizing the existing knowledge on the interplay between the heart and the vessels in the presence of degenerative aortic stenosis, prior, upon and after interventional management. Further, it discusses the evidence supporting the potential clinical application of arterial biomarkers for the assessment of progression, severity, management and prognosis of aortic stenosis.

MicroRNA-383-5p regulates osteogenic differentiation of human periodontal ligament stem cells by targeting histone deacetylase 9

OBJECTIVE

Human periodontal ligament stem cells (hPDLSCs) play an important role in regenerative engineering technology for periodontal therapy. The mechanism of microRNA (miR)-383-5p in osteogenic differentiation needs further exploration. This study aimed at investigating the potential role of miR-383-5p in the osteogenic differentiation of hPDLSCs.

METHODS

Osteogenic differentiation of hPDLSCs was induced by osteoblastinducing media and evaluated by Alizarin Red staining and Alkaline phosphatase staining. To examine the role of miR-383-5p in osteogenic differentiation, miR-383-5p mimic or inhibitor and histone deacetylase (HDAC) 9 overexpression plasmid or siRNA-HDAC9 were co-transfected into hPDLSCs. qRT-PCR and Western blot were applied for detection of mRNA and protein levels.

RESULTS

During the osteogenic differentiation of hPDLSCs, miR-383-5p expression was gradually up-regulated, while HDAC9 mRNA level was down-regulated. HDAC9 overexpression suppressed Alkaline phosphatase activity, mineral node formation and the expressions of osteogenic markers including Runx family transcription factor 2 (RUNX2), osteocalcin and Smad family member 4 (Smad4) in the differentiated hPDLSCs, while siHDAC9 exerted opposite effects on osteogenic differentiation. The Alkaline phosphatase activity, mineral node formation and the expressions of RUNX2, osteocalcin and Smad4 of the differentiated hPDLSCs were regulated by miR-383-5p/HDAC9 axis. The miR-383-5p/HDAC9 axis effectively regulated the expressions of osteogenic markers during the differentiation of hPDLSCs.

CONCLUSION

MiR-383-5p overexpression facilitated the osteogenic differentiation of hPDLSCs via inhibiting HDAC9 expression.

A novel detergent-based decellularization combined with carbodiimide crosslinking for improving anti-calcification of bioprosthetic heart valve

Currently, valve replacement surgery is the only therapy for the end-stage valvular diseases because of the inability of regeneration for diseased heart valves. Bioprosthetic heart valves (BHVs), which are mainly derived from glutaraldehyde (GA) crosslinked porcine aortic heart valves or bovine pericardium, have been widely used in the last decades. However, it is inevitable that calcification and deterioration may occur within 10-15 years, which are still the main challenges for the BHVs in clinic. In this study, N-Lauroylsarcosine sodium salt (SLS) combined with N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (EDC) and N-hydroxysuccinimide (NHS) were utilized to decellularize and crosslink the heart valves instead of GA treatment. The obtained BHVs exhibited excellent extracellular matrix stability and mechanical properties, which were similar with GA treatment. Moreover, the obtained BHVs exhibited betterin vitrobiocompatibilities than GA treatment. After subcutaneous implantation for 30 d, the obtained BHVs showed mitigated immune response and reduced calcification compare with GA treatment. Therefore, all the above results indicated that the treatment of SLS-based decellularization combined with EDC/NHS crosslink should be a promising method to fabricate BHVs which can be used in clinic in future.

Effect of Porphyromonas gingivalis lipopolysaccharide on calcification of human umbilical artery smooth muscle cells co-cultured with human periodontal ligament cells

Periodontitis is an independent risk factor for coronary heart disease. Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) was considered to be one of the main virulence factors. In addition, vascular smooth muscle cells transform into osteoblast-like cells in an arterial calcification process under chronic inflammatory conditions. The present study aimed to determine the calcification induced by Pg-LPS in human umbilical artery smooth muscle cells (HUASMCs) co-cultured with human periodontal ligament cells (HPDLCs). An in vitro co-culture system was established using Transwell inserts. HUASMC proliferation and alkaline phosphatase (ALP) activity were measured with a Cell Counting Kit-8 and an ALP kit, respectively. Calcium nodule formation was detected using alizarin red S staining. The effects of Pg-LPS on the mRNA expression of the calcification genes of ALP, core-binding factor α1 (Runx2) and bone sialoprotein (BSP) were assessed using reverse transcription-quantitative PCR. The results indicated that Pg-LPS increased HUASMC proliferation and ALP activity. Furthermore, among all of the groups, calcium nodule formation was most extensive in co-cultured cells in the mineralization-inducing medium containing Pg-LPS. In addition, the expression of specific osteogenic genes (Runx2, ALP and BSP) significantly increased in the presence of Pg-LPS and mineralization-inducing medium, which was further enhanced in co-culture with HPDLCs. In conclusion, co-culture with HPDLCs increased the effect of Pg-LPS to stimulate the calcification of HUASMCs. It was suggested that besides the inflammation, periodontitis may promote the occurrence of vascular calcification. The study indicated that periodontal treatment of subgingival scaling to reduce and/or control Porphyromonas gingivalis may decrease the occurrence or severity of vascular calcification.

The Dual Role of Vitamin K2 in "Bone-Vascular Crosstalk": Opposite Effects on Bone Loss and Vascular Calcification

Osteoporosis (OP) and vascular calcification (VC) represent relevant health problems that frequently coexist in the elderly population. Traditionally, they have been considered independent processes, and mainly age-related. However, an increasing number of studies have reported their possible direct correlation, commonly defined as “bone-vascular crosstalk”. Vitamin K2 (VitK2), a family of several natural isoforms also known as menaquinones (MK), has recently received particular attention for its role in maintaining calcium homeostasis. In particular, VitK2 deficiency seems to be responsible of the so-called “calcium paradox” phenomenon, characterized by low calcium deposition in the bone and its accumulation in the vessel wall. Since these events may have important clinical consequences, and the role of VitK2 in bone-vascular crosstalk has only partially been explained, this review focuses on its effects on the bone and vascular system by providing a more recent literature update. Overall, the findings reported here propose the VitK2 family as natural bioactive molecules that could be able to play an important role in the prevention of bone loss and vascular calcification, thus encouraging further in-depth studies to achieve its use as a dietary food supplement.

New calcification model for intact murine aortic valves

Calcific aortic valve disease (CAVD) is a common progressive disease of the aortic valves, for which no medical treatment exists and surgery represents currently the only therapeutic solution. The development of novel pharmacological treatments for CAVD has been hampered by the lack of suitable test-systems, which require the preservation of the complex valve structure in a mechanically and biochemical controllable system. Therefore, we aimed at establishing a model which allows the study of calcification in intact mouse aortic valves by using the Miniature Tissue Culture System (MTCS), an ex vivo flow model for whole mouse hearts. Aortic valves of wild-type mice were cultured in the MTCS and exposed to osteogenic medium (OSM, containing ascorbic acid, β-glycerophosphate and dexamethasone) or inorganic phosphates (PI). Osteogenic calcification occurred in the aortic valve leaflets that were cultured ex vivo in the presence of PI, but not of OSM. In vitro cultured mouse and human valvular interstitial cells calcified in both OSM and PI conditions, revealing in vitro-ex vivo differences. Furthermore, endochondral differentiation occurred in the aortic root of ex vivo cultured mouse hearts near the hinge of the aortic valve in both PI and OSM conditions. Dexamethasone was found to induce endochondral differentiation in the aortic root, but to inhibit calcification and the expression of osteogenic markers in the aortic leaflet, partly explaining the absence of calcification in the aortic valve cultured with OSM. The osteogenic calcifications in the aortic leaflet and the endochondral differentiation in the aortic root resemble calcifications found in human CAVD. In conclusion, we have established an ex vivo calcification model for intact wild-type murine aortic valves in which the initiation and progression of aortic valve calcification can be studied. The in vitro-ex vivo differences found in our studies underline the importance of ex vivo models to facilitate pre-clinical translational studies.

From organic and inorganic phosphates to valvular and vascular calcifications

Calcification of the arterial wall and valves is an important part of the pathophysiological process of peripheral and coronary atherosclerosis, aortic stenosis, ageing, diabetes, and chronic kidney disease. This review aims to better understand how extracellular phosphates and their ability to be retained as calcium phosphates on the extracellular matrix initiate the mineralization process of arteries and valves. In this context, the physiological process of bone mineralization remains a human model for pathological soft tissue mineralization. Soluble (ionized) calcium precipitation occurs on extracellular phosphates; either with inorganic or on exposed organic phosphates. Organic phosphates are classified as either structural (phospholipids, nucleic acids) or energetic (corresponding to phosphoryl transfer activities). Extracellular phosphates promote a phenotypic shift in vascular smooth muscle and valvular interstitial cells towards an osteoblast gene expression pattern, which provokes the active phase of mineralization. A line of defense systems protects arterial and valvular tissue calcifications. Given the major roles of phosphate in soft tissue calcification, phosphate mimetics, and/or prevention of phosphate dissipation represent novel potential therapeutic approaches for arterial and valvular calcification.

Insights into the mechanism of vascular endothelial cells on bone biology

In the skeletal system, blood vessels not only function as a conduit system for transporting gases, nutrients, metabolic waste, or cells but also provide multifunctional signal molecules regulating bone development, regeneration, and remodeling. Endothelial cells (ECs) in bone tissues, unlike in other organ tissues, are in direct contact with the pericytes of blood vessels, resulting in a closer connection with peripheral connective tissues. Close-contact ECs contribute to osteogenesis and osteoclastogenesis by secreting various cytokines in the paracrine or juxtacrine pathways. An increasing number of studies have revealed that extracellular vesicles (EVs) derived from ECs can directly regulate maturation process of osteoblasts and osteoclasts. The different pathways focus on targets at different distances, forming the basis of the intimate spatial and temporal link between bone tissue and blood vessels. Here, we provide a systematic review to elaborate on the function of ECs in bone biology and its underlying mechanisms based on three aspects: paracrine, EVs, and juxtacrine. This review proposes the possibility of a therapeutic strategy targeting blood vessels, as an adjuvant treatment for bone disorders.

A method for simultaneously crosslinking and functionalizing extracellular matrix-based biomaterials as bioprosthetic heart valves with enhanced endothelialization and reduced inflammation

With the coming of an aging society and the emergence of transcatheter valve technology, the implantation of bioprosthetic heart valves (BHVs) in patients with valvular disease has significantly increased worldwide. Currently, most clinically available BHVs are crosslinked with glutaraldehyde (GLUT). However, the GLUT treated BHV is less durable due to the combined effect of multiple factors such as cytotoxicity, immune responses, and calcification. In this study, the in-situ polymerization of sulfonic monomers with a decellularized extracellular matrix (ECM) was performed to simultaneously achieve the crosslinking and functionalization of ECM. Subsequently, the feasibility of the hybrid ECM used as leaflet material of BHV was evaluated. In in-vitro tests, the results indicated that the hybrid ECM fixed collagen efficiently and the introduction of sulfonic polymer promoted the proliferation and migration of human umbilical vein endothelial cells (HUVECs). In in-vivo tests, after being implanted in SD rats and mice, the hybrid ECM significantly inhibited immune response and calcification compared with the non-hybrid counterpart and GLUT crosslinked tissue. These results indicated that the hybrid ECM exhibited more competitive stability and better biocompatibility compared to these features in GLUT-crosslinked valve. Therefore, the sulfonic polymer hybrid ECM provides a potential material for more durable BHV and the in-situ polymerization strategy can serve as a general treatment method for tissue crosslinking as well as tailoring the biophysical properties of ECM.

YAP/TAZ Are Required to Suppress Osteogenic Differentiation of Vascular Smooth Muscle Cells

Vascular smooth muscle cells (VSMCs) represent the prevailing cell type of arterial vessels and are essential for blood vessel structure and homeostasis. They have substantial potential for phenotypic plasticity when exposed to various stimuli in their local microenvironment. How VSMCs maintain their differentiated contractile phenotype is still poorly understood. Here we demonstrate that the Hippo pathway effectors YAP and TAZ play a critical role in maintaining the differentiated contractile phenotype of VSMCs. In the absence of YAP/TAZ, VSMCs lose their differentiated phenotype and undergo osteogenic differentiation, which results in vascular calcification. Osteogenic transdifferentiation was accompanied by the upregulation of Wnt target genes. The absence of YAP/TAZ in VSMCs led to Disheveled 3 (DVL3) nuclear translocation and upregulation of osteogenesis-associated genes independent of canonical Wnt/β-catenin signaling activation. Our data indicate that cytoplasmic YAP/TAZ interact with DVL3 to avoid its nuclear translocation and osteogenic differentiation, thereby maintaining the differentiated phenotype of VSMCs.

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YAP/TAZ play an important role in maintaining vascular SMCs contractile phenotype

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Loss of YAP/TAZ in vSMCs leads to reduced expression of smooth muscle marker genes

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Loss of YAP/TAZ in vSMCs results in reduced artery contractility

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Deficiency of YAP/TAZ in vSMCs leads to osteogenic transdifferentiation

CircRNAs and LncRNAs in Osteoporosis

Osteoporosis is a systemic bone disease with bone fragility and increased fracture risk. The non-coding RNAs (ncRNAs) have appeared as important regulators of cellular signaling and pertinent human diseases. Studies have demonstrated that circular RNAs (circRNAs) and long non-coding RNAs (lncRNAs) are involved in the progression of osteoporosis through a variety of pathways, and are considered as targets for the prophylaxis and treatment of osteoporosis. Based on an in-depth understanding of their roles and mechanisms in osteoporosis, we summarize the functions and molecular mechanisms of circRNAs and lncRNAs involved in the progression of osteoporosis and provide some new insights for the prognosis, diagnosis and treatment of osteoporosis.

Aldo-keto reductase family 1 member B induces aortic valve calcification by activating hippo signaling in valvular interstitial cells

AIMS

Calcific aortic valve disease (CAVD) is a primary cause of cardiovascular mortality; however, its mechanisms are unknown. Currently, no effective pharmacotherapy is available for CAVD. Aldo-keto reductase family 1 member B (Akr1B1) has been identified as a potential therapeutic target for valve interstitial cell calcification. Herein, we hypothesized that inhibition of Akr1B1 can attenuate aortic valve calcification.

METHODS AND RESULTS

Normal and degenerative tricuspid calcific valves from human samples were analyzed by immunoblotting and immunohistochemistry. The results showed significant upregulation of Akr1B1 in CAVD leaflets. Akr1B1 inhibition attenuated calcification of aortic valve interstitial cells in osteogenic medium. In contrast, overexpression of Akr1B1 aggravated calcification in osteogenic medium. Mechanistically, using RNA sequencing (RNAseq), we revealed that Hippo-YAP signaling functions downstream of Akr1B1. Furthermore, we established that the protein level of the Hippo-YAP signaling effector active-YAP had a positive correlation with Akr1B1. Suppression of YAP reversed Akr1B1 overexpression-induced Runx2 upregulation. Moreover, YAP activated the Runx2 promoter through TEAD1 in a manner mediated by ChIP and luciferase reporter systems. Animal experiments showed that the Akr1B1 inhibitor epalrestat attenuated aortic valve calcification induced by a Western diet in LDLR^-/- mice.

CONCLUSION

This study demonstrates that inhibition of Akr1B1 can attenuate the degree of calcification both in vitro and in vivo. The Akr1B1 inhibitor epalrestat may be a potential treatment option for CAVD.

Walking performance is associated with coronary artery calcification in very old adults

BACKGROUND

Coronary artery calcification (CAC) scores have good predictive value for atherosclerosis-related outcomes in the geriatric population. The low availability of cardiac computed tomography is an obstacle to assess CAC in clinical practice. Thus, clinical signs with a good degree of association with CAC can help to estimate cardiovascular risk, particularly in low-income populations.

OBJECTIVES

To assess whether clinical, biochemical and functional measures explain the CAC scores in older individuals.

METHODS

We characterized 89 non-institutionalized older volunteers (≥ 80 years old) by means of a comprehensive biochemical and anthropometric evaluation along with assessments of CAC scores determined by computerized tomography, and tested their association with walking speed test (WS) and handgrip strength (HS) performance.

RESULTS

Analyses of variance showed that body mass index (BMI) and waist circumference (WC) differed significantly (p ≤ 0.01 and p ≤ 0.03; respectively) across quartiles, so that subsequent tests were adjusted for anthropometry. ANCOVA revealed that the two lower quartiles of CAC had better performance in WS compared to the third and fourth quartiles (p ≤ 0.04). Multinomial logistic regression analysis showed that WS scores exhibit enough power (R² = 0.379, p = 0.05) to explain CAC scores. There were no significant differences for HS between quartiles (p = 0.87).

CONCLUSION

WS is associated and explain CAC scores, and may be useful to stratify atherosclerotic burden in apparently healthy very old individuals regardless of body composition.

MicroRNA Profiles in Calcified and Healthy Aorta Differ: Therapeutic Impact of miR-145 and miR-378

Our goal was to elucidate microRNAs (miRNAs) that may repress the excess bone morphogenetic protein (BMP) signaling observed during pathological calcification in the Klotho mouse model of kidney disease. We hypothesized that restoring healthy levels of miRNAs that post-transcriptionally repress osteogenic calcific factors may decrease aortic calcification. Our relative abundance profiles of miRNAs in healthy aorta differ greatly from those in calcified mouse aorta. Many of these miRNAs are predicted to regulate proteins involved in BMP signaling and may control osteogenesis. Two differentially regulated miRNAs, miR-145 and miR-378, were selected based on three criteria: reduced levels in calcified aorta, the ability to target more than one protein in the BMP signaling pathway, and conservation of targeted sequences between humans and mice. Forced expression using a lentiviral vector demonstrated that restoring normal levels repressed the synthesis of BMP2 and other pro-osteogenic proteins and inhibited pathological aortic calcification in Klotho mice with renal insufficiency. This study identified miRNAs that may impact BMP signaling in both sexes and demonstrated the efficacy of selected miRNAs in reducing aortic calcification in vivo. Calcification of the aorta and the aortic valve resulting from abnormal osteogenesis is common in those with kidney disease, diabetes, and high cholesterol. Such vascular osteogenesis is a clinically significant feature. The calcification modulating miRNAs described here are candidates for biomarkers and "miRNA replacement therapies" in the context of chronic kidney disease and other pro-calcific conditions.

Attenuating Effects of Pyrogallol-Phloroglucinol-6,6-Bieckol on Vascular Smooth Muscle Cell Phenotype Changes to Osteoblastic Cells and Vascular Calcification Induced by High Fat Diet

Advanced glycation end products/receptor for AGEs (AGEs/RAGEs) or Toll like receptor 4 (TLR4) induce vascular smooth muscle cell (VSMC) phenotype changes in osteoblast-like cells and vascular calcification. We analyzed the effect of Ecklonia cava extract (ECE) or pyrogallol-phloroglucinol-6,6-bieckol (PPB) on VSMC phenotype changes and vascular calcification prompted by a high-fat diet (HFD). HFD unregulated RAGE, TLR4, transforming growth factor beta (TGFβ), bone morphogenetic protein 2 (BMP2), protein kinase C (PKC), and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signals in the aorta of mice. ECE and PPB restored the increase of those signal pathways. AGE- or palmitate-treated VSMC indicated similar changes with the animal. HFD increased osteoblast-like VSMC, which was evaluated by measuring core-binding factor alpha-1 (CBFα-1) and osteocalcin expression and alkaline phosphatase (ALP) activity in the aorta. ECE and PPB reduced vascular calcification, which was analyzed by the calcium deposition ratio, and Alizarin red S stain was increased by HFD. PPB and ECE reduced systolic, diastolic, and mean blood pressure, which increased by HFD. PPB and ECE reduced the phenotype changes of VSMC to osteoblast-like cells and vascular calcification and therefore lowered the blood pressure.

Cumulative Rheumatic Inflammation Modulates the Bone-Vascular Axis and Risk of Coronary Calcification

Background

Rheumatic diseases are related to both abnormal bone turnover and atherogenesis, but a mechanistic link was missing.

Methods and Results

We investigated the effect of cumulative rheumatic inflammation (CRI) on risk of coronary calcification in a retrospective cohort of 145 rheumatoid arthritis patients. A time‐adjusted aggregate CRI score was derived by conglomerating all quarterly biomarker encounters of serum C‐reactive protein over 60 months immediately preceding computed tomography coronary angiography. Flow cytometry was performed to measure the osteocalcin‐positive (OCN⁺) CD34⁺KDR⁺ and OCN⁺CD34⁺ circulating endothelial progenitor cells (EPCs). Conventional early circulating EPCs CD34⁺CD133⁺KDR⁺ was determined. Coronary calcification was defined as any Agatston score >0. 50% of patients (n=72/145) had coronary calcification. CRI score was associated with presence of coronary calcification (P=0.004) (multivariable‐adjusted: highest versus lowest quartile: odds ratio=5.6 [95% CI 1.1–28.9], P=0.041). Receiver operating characteristics curve revealed divergent behavior of OCN‐expressing circulating EPCs (OCN⁺CD34⁺EPCs: area under the curve=0.60, P=0.034; OCN⁺CD34⁺KDR⁺EPCs: area under the curve=0.59, P=0.053, positive predictors) versus conventional early EPCs (CD34⁺CD133⁺KDR⁺: area under the curve=0.60, P=0.034, negative predictor) for coronary calcification, which persisted after multivariable adjustments (OCN⁺CD34⁺KDR⁺ [>75th percentile]: odds ratio=7.2 [95% CI 1.8–27.9], P=0.005; OCN⁺CD34⁺EPCs [>75th percentile]: odds ratio=6.0 [95% CI 1.5–23.3], P=0.010; CD34⁺CD133⁺KDR⁺ [>75th percentile: odds ratio=0.3 [95% CI 0.1–1.0], P=0.053). Intriguingly, the CRI score was associated with increased OCN⁺CD34⁺EPCs (highest versus lowest quartile: B=+25.6 [95% CI 0.8–50.5] [×10³/mL peripheral blood], P=0.043), but reduced CD34⁺CD133⁺KDR⁺EPCs (highest versus lowest quartile: B=−16.2 [95% CI −31.5 to −0.9], P=0.038).

Conclusions

Preceding 60 months of CRI is associated with increased risk of coronary calcification and altered OCN expression in circulating EPCs.

A novel role of FKN/CX3CR1 in promoting osteogenic transformation of VSMCs and atherosclerotic calcification

Fractalkine (FKN) and its specific receptor CX3CR1 play a critical role in the pathogenesis of atherosclerosis including recruitment of vascular cells and the development of inflammation. However, its contribution to regulating the development of atherosclerotic calcification has not been well documented. Osteogenic transformation of vascular smooth muscle cells (VSMCs) is critical in the development of calcification in atherosclerotic lesions. In this study, for the first time, we evaluated the effect of FKN/CX3CR1 on the progression of VSMCs calcification and defined molecular signaling that is operative in the FKN/CX3CR1-induced osteogenic transformation of VSMCs. We found that high-fat diet induced atherosclerotic calcification in vivo was markedly inhibited in the Apolipoprotein E (ApoE) and CX3CR1 deficient (ApoE^-/-/CX3CR1^-/-) mice compared with their control littermates. FKN and CX3CR1 were both expressed in VSMCs and up-regulated by oxidized low-density lipoprotein (ox-LDL). FKN/CX3CR1 promoted the expression of osteogenic markers, including osteopontin (OPN), bone morphogenetic protein (BMP)-2 and alkaline phosphatase (ALP) and decreased VSMCs markers, including smooth muscle (SM) α-actin and SM22-α in a dose-dependent manner. The essential role of FKN/CX3CR1 in VSMCs calcification was further confirmed by lentivirus-mediated knockdown or overexpression of CX3CR1 blocked or accelerated osteogenic transformation of VSMCs. This response was associated with reciprocal up- and down-regulation of osteogenic factor, runt-related transcription factor 2 (RUNX2), transcription factors in osteoclast differentiation, receptor activator of nuclear factor-κB (RANK), RANK ligand (RNAKL) and osteoprotegerin (OPG), respectively. Inhibition of FKN/CX3CR1-activated Jak2/Stat3 signaling by the Jak/Stat inhibitor AG490 blocked osteogenic transformation of VSMCs and RUNX2 induction concurrently. Taken together, our data uncovered novel roles of FKN/CX3CR1 in promoting VSMC osteogenic transformation and atherosclerotic calcification by activating RUNX2 through Jak2/Stat3 signaling pathway and suppressing OPG. Our findings suggest that targeting FKN/CX3CR1 may provide new strategies for the prevention and treatment of atherosclerotic calcification.

Inorganic phosphate-osteogenic induction medium promotes osteogenic differentiation of valvular interstitial cells via the BMP-2/Smad1/5/9 and RhoA/ROCK-1 signaling pathways

Calcific aortic valve disease (CAVD) currently lacks a highly effective in vitro model. The presence of high concentrations of serum inorganic phosphate in patients with end-stage renal disease leads to calcification of vascular and aortic valves. Therefore, we applied inorganic phosphate to induce the osteogenic differentiation of valvular interstitial cells (VICs) and mimic its in vivo pathophysiological effects. Calcification and inflammatory response assays determined that inorganic phosphate-osteogenic induction medium (IP-OIM) was more efficient than classic osteogenic induction medium (OIM) containing organic glycerophosphate. Levels of BMP-2, RhoA, and ROCK-1 were significantly increased in IP-OIM cells. Knockdown efficiency of BMP-2- and RhoA-siRNA in VICs was evaluated, and expression of RhoA and its downstream target ROCK-1 was decreased after BMP-2-siRNA transfection. Moreover, ROCK-1 was significantly downregulated after RhoA knockdown, whereas expression of BMP-2 was unchanged. Interference of BMP-2 had a stronger anti-calcification effect than RhoA, further identifying BMP-2 as an upstream regulator of RhoA/ROCK-1. Stimulation of VICs by IP-OIM led to increased Smad1/5/9 phosphorylation, which peaked at 60 min, while pre-treatment of VICs with the Smad1/5/9 inhibitor Compound C attenuated VICs calcification. These results suggest that IP-OIM induced VICs osteogenic differentiation via Smad1/5/9 signaling. Knockdown of BMP-2 or RhoA also decreased Smad1/5/9 phosphorylation also decreased. We conclude that the RhoA/ROCK-1 axis participates in VICs osteogenic differentiation as a "bypass mediator" of the BMP-2/Smad1/5/9 signaling pathway.

Farnesoid X receptor activation inhibits TGFBR1/TAK1-mediated vascular inflammation and calcification via miR-135a-5p

Chronic inflammation plays a crucial role in vascular calcification. However, only a few studies have revealed the mechanisms underlying the development of inflammation under high-phosphate conditions in chronic kidney disease (CKD) patients. Here, we show that inflammation resulting from the activation of the TGFBR1/TAK1 pathway is involved in calcification in CKD rats or osteogenic medium-cultured human aortic smooth muscle cells (HASMCs). Moreover, miR-135a-5p is demonstrated to be a key regulator of the TGFBR1/TAK1 pathway, which has been reported to be decreased in CKD rats. We further reveal that farnesoid X receptor (FXR) activation increases miR-135a-5p expression, thereby inhibiting the activation of the TGFBR1/TAK1 pathway, ultimately resulting in the attenuation of vascular inflammation and calcification in CKD rats. Our findings provide advanced insights into the mechanisms underlying the development of inflammation in vascular calcification, and evidence that FXR activation could serve as a therapeutic strategy for retarding vascular calcification in CKD patients.

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.

Cyclophilin A inhibition as potential treatment of human aortic valve calcification

Aortic valve stenosis (AS) is a pathological condition that affects about 3% of the population, representing the most common valve disease. The main clinical feature of AS is represented by the impaired leaflet motility, due to calcification, which leads to the left ventricular outflow tract obstruction during systole. The formation and accumulation of calcium nodules are driven by valve interstitial cells (VICs). Unfortunately, to date, the in vitro and in vivo studies were not sufficient to fully recapitulate all the pathological pathways involved in AS development, as well as to define a specific and effective pharmacological treatment for AS patients. Cyclophilin A (CyPA), the most important immunophilin and endogenous ligand of cyclosporine A (CsA), is strongly involved in several detrimental cardiovascular processes, such as calcification. To date, there are no data on the CyPA role in VIC-mediated calcification process of AS. Here, we aimed to identify the role of CyPA in AS by studying VIC calcification, in vitro. In this study, we found that (i) CyPA is up-regulated in stenotic valves of AS patients, (ii) pro-calcifying medium promotes CyPA secretion by VICs, (iii) in vitro treatment of VICs with exogenous CyPA strongly stimulates calcium deposition, and (iv) exogenous CyPA inhibition mediated by CsA analogue MM284 abolished in vitro calcium potential. Thus, CyPA represents a biological target that may act as a novel candidate in the detrimental AS development and its inhibition may provide a novel pharmacological approach for AS treatment.

Serum uric acid level is associated with the incidence of heterotopic ossification following elbow trauma surgery

BACKGROUND

Heterotopic ossification (HO) is a common complication after surgery for elbow trauma. Uric acid is the end product of purine metabolism and has several physiological and pathogenic roles. However, the relationship between HO and uric acid has not been explored. This retrospective study aimed to assess the relationship between HO and serum uric acid (SUA).

MATERIAL AND METHODS

We retrospectively reviewed data from 155 patients undergoing elbow trauma surgery in our hospital between January 2013 and December 2018. One hundred patients were included according to the inclusion criteria. They were divided into 2 groups according to the presence or absence of HO, and the SUA level was compared between groups using the independent samples t test. The optimal prognostic cutoff value was obtained using the maximum value of the Youden index.

RESULTS

The SUA level was significantly higher in the HO group than in the non-HO group (362.0 ± 87.4 μmol/L vs. 318.3 ± 87.0 μmol/L; P < .05). Using the maximum value of Youden index, 317.5 μmol/L was determined to be the optimal SUA cutoff value for the prediction of HO, with a sensitivity of 68.75% (95% confidence interval [CI], 54.67%-80.05%) and specificity of 55.77% (95% CI, 42.34%-68.40%).

CONCLUSIONS

Our study was the first to find that the high SUA level is a risk factor for HO of the elbow joint after trauma. Moreover, 317.5 μmol/L is the SUA threshold predicting the occurrence and development of HO of the elbow, with high sensitivity and specificity.