From organic and inorganic phosphates to valvular and vascular calcifications

Roadmap for alleviating the manifestations of ageing in the cardiovascular system

Ageing of the cardiovascular system is associated with frailty and various life-threatening diseases. As global populations grow older, age-related conditions increasingly determine healthspan and lifespan. The circulatory system not only supplies nutrients and oxygen to all tissues of the human body and removes by-products but also builds the largest interorgan communication network, thereby serving as a gatekeeper for healthy ageing. Therefore, elucidating organ-specific and cell-specific ageing mechanisms that compromise circulatory system functions could have the potential to prevent or ameliorate age-related cardiovascular diseases. In support of this concept, emerging evidence suggests that targeting the circulatory system might restore organ function. In this Roadmap, we delve into the organ-specific and cell-specific mechanisms that underlie ageing-related changes in the cardiovascular system. We raise unanswered questions regarding the optimal design of clinical trials, in which markers of biological ageing in humans could be assessed. We provide guidance for the development of gerotherapeutics, which will rely on the technological progress of the diagnostic toolbox to measure residual risk in elderly individuals. A major challenge in the quest to discover interventions that delay age-related conditions in humans is to identify molecular switches that can delay the onset of ageing changes. To overcome this roadblock, future clinical trials need to provide evidence that gerotherapeutics directly affect one or several hallmarks of ageing in such a manner as to delay, prevent, alleviate or treat age-associated dysfunction and diseases.

Calcific aortic stenosis: omics-based target discovery and therapy development

Calcific aortic valve disease (CAVD) resulting in aortic stenosis (AS) is the most common form of valvular heart disease, affecting 2% of those over age 65. Those who develop symptomatic severe AS have an average further lifespan of <2 years without valve replacement, and three-quarters of these patients will develop heart failure, undergo valve replacement, or die within 5 years. There are no approved pharmaceutical therapies for AS, due primarily to a limited understanding of the molecular mechanisms that direct CAVD progression in the complex haemodynamic environment. Here, advances in efforts to understand the pathogenesis of CAVD and to identify putative drug targets derived from recent multi-omics studies [including (epi)genomics, transcriptomics, proteomics, and metabolomics] of blood and valvular tissues are reviewed. The recent explosion of single-cell omics-based studies in CAVD and the pathobiological and potential drug discovery insights gained from the application of omics to this disease area are a primary focus. Lastly, the translation of knowledge gained in valvular pathobiology into clinical therapies is addressed, with a particular emphasis on treatment regimens that consider sex-specific, renal, and lipid-mediated contributors to CAVD, and ongoing Phase I/II/III trials aimed at the prevention/treatment of AS are described.

Serum Ionized Calcium as a Prognostic Biomarker in Type B Aortic Dissection After Endovascular Treatment

OBJECTIVE

Lower serum ionized calcium (iCa2+) was reported to be associated with a higher risk of adverse events in patients with cardiovascular diseases. This study aimed to investigate the associations between preoperative serum iCa2+ and outcomes of type B aortic dissection (TBAD) patients receiving thoracic endovascular aortic repair (TEVAR).

METHODS

Between January 2016 and December 2019, 491 TBAD patients received TEVAR in a single center. Patients with acute or subacute TBAD were included. Serum iCa2+ (pH 7.4) was obtained from the arterial blood gas analysis before TEVAR. The study population was grouped into the hi-Ca group (1.11 mmol/L ≤ iCa2+ < 1.35 mmol/L) and lo-Ca group (iCa2+ < 1.11 mmol/L). The primary outcomes were all-cause mortality. The secondary outcomes were any major adverse clinical events (MACEs), which included all-cause mortality and aortic-related severe complications. To eliminate bias, 1:1 propensity score matching (PSM) was conducted.

RESULTS

Overall, 396 TBAD patients were included in this study. In the total population, there were 119 (30.1%) patients in the lo-Ca group. After PSM, 77 matched pairs were obtained for further analysis. In the matched population, the 30-day mortality and 30-day MACEs between the two groups presented significant differences (p=0.023 and 0.029, respectively). At 5 years, cumulative incidences of mortality (log-rank p<0.001) and MACEs (log-rank p=0.016) were significantly higher in the lo-Ca group than that of the hi-Ca group. Multivariate cox regression analysis indicated that lower preoperative iCa2+ (hazard ratio for per 0.1 mmol/L decrease, 2.191; 95% confidence interval, 1.487-3.228, p<0.001) was an independent risk factor for 5-year mortality after PSM.

CONCLUSIONS

Lower preoperative serum iCa2+ might have an association with 5-year mortality in TBAD patients after TEVAR. Serum iCa2+ monitoring in this population may facilitate the identification of critical conditions.

CLINICAL IMPACT

Our present study found that the cutoff value of preoperative serum iCa2+ 1.11 mmol/L, which is slightly lower than the lower limit of the normal range of 1.15-1.35 mmol/L, worked relatively well for discerning the high-risk and low-risk TBAD patients at 5 years. Serum iCa2+ monitoring in TBAD patients receiving TEVAR may facilitate the identification of critical conditions.

Biomaterials-mediated biomineralization for tumor blockade therapy

Recent advancements in tumor therapy have underscored the potential of biomaterials-mediated biomineralization for tumor blockade. By precisely regulating biomineralization and constructing nanomineralized structures at the cellular level, this therapy achieves multi-dimensional targeted inhibition of tumors. Mineralized precursor molecules are engineered to selectively recognize and bind to proteins on the tumor cell membrane, obstructing signal transduction. Biomineralized materials directly target the tumor cell membrane, disrupting its biological functions and inducing cell apoptosis. Additionally, these materials infiltrate the mitochondria of tumor cells, disrupting energy metabolism through mineralization and significantly impairing tumor viability. This biomaterials-mediated approach enhances treatment precision and efficacy while mitigating side effects, offering a unique approach to tumor therapy.

ROS Scavenging and Osteogenic Differentiation Potential of L-Methionine-Substituted Poly(Organophosphazene) Electrospun Fibers

This study investigated the application of poly[bis (ethylmethionato) phosphazene] (PαAPz-M) electrospun fibers in tissue engineering, focusing on their reactive oxygen species (ROS) scavenging capabilities and material-directed cell behavior, including the influence of their degradation products on cell viability and differentiation, and the scaffold topography's influence on cell alignment. The ROS scavenging ability of PαAPz-M was assessed by DPPH assay, and then PαAPz-M's protection against exogenous ROS was studied. The results showed enhanced cell viability on PαAPz-M fiber mats under oxidative stress conditions. This study also investigated the effects of the degradation products of PαAPz-M on cell viability and osteogenic differentiation. It was observed that the late-stage degradation product, phosphoric acid, can significantly influence the osteogenic differentiation of MSCs. In contrast, methionine, which is the early-stage degradation product, showed a minimal influence. Additionally, the study fabricated fiber mats that can lead to enhanced cell alignment while maintaining high porosity. Collectively, this study expanded the applications of PαAPz-M fiber mat protection against oxidative stress and guiding osteogenic differentiation and cell alignment.

Amyloid and collagen templates in aortic valve calcification

Calcific aortic valve disease (CAVD) is a widely prevalent heart disorder in need of pharmacological interventions. Calcified areas in aortic valves often contain amyloid fibrils that promote calcification in vitro. This opinion paper suggests that amyloid contributes to CAVD development; amyloid-assisted nucleation can accelerate hydroxyapatite deposition onto collagen matrix. Notably, acidic arrays in amyloid match calcium-calcium spacing in the amorphous hydroxyapatite precursor, while oscillating hemodynamic perturbations promote amyloid deposition in the valve. Lipoprotein(a), a genetic risk factor for CAVD, augments calcification via several mechanisms, wherein hydrolysis of oxidized phospholipids (oxPLs) by Lp(a)-associated enzymes helps generate orthophosphate, and apolipoprotein(a) blocks plasmin-induced fibril degradation. Current studies of amyloid-calcium-collagen interactions in solution and in fibrillar complexes allow deeper insight into the role of amyloid in calcification.

Combinations of valvular calcification and serum alkaline phosphatase predict cardiovascular risk among end-stage kidney disease patients

Background

Valvular calcification (VC) refers to the calcified valvular remodeling associated with kidney dysfunction, especially end-stage kidney disease (ESKD). ESKD patients with VC had significantly higher cardiovascular risk than those without. Factors interacted with VC regarding prognostic prediction in this population were seldom investigated. We aimed to examine the potential synergetic effects of VC and alkaline phosphatase (Alk-P) on ESKD patients' cardiovascular risk and mortality.

Methods

ESKD patients undergoing hemodialysis were prospectively enrolled from a medical center in 2018. We identified patients with echocardiography and available serum Alk-P levels. Cox proportional hazard regression was performed to analyze the risk of major adverse cardiovascular events (MACEs), cardiovascular and overall mortality among 4 participant groups (with or without VC versus low or high Alk-P levels). The models were further adjusted for age, sex, and clinical variables.

Results

Of the 309 ESKD patients, 38, 46, 112, and 113 had no VC with low Alk-P, no VC with high Alk-P, VC with low Alk-P, and VC with high Alk-P, respectively. After adjusting for age and sex, patients with VC and high Alk-P had a higher risk of developing MACE, cardiovascular and overall mortality (HR, 3.07, 3.67, 3.65; 95% CI 1.38-6.84, 1.1-12.24, 1.29-10.36, respectively). Patients with VC and high Alk-P remained at higher risk of MACE (HR, 2.76; 95% CI 1.17-6.48) than did those without VC and with low Alk-P.

Conclusion

Serum Alk-P could be used to identify a subgroup of ESKD patients with elevated cardiovascular risk among those with VC.

Unmet needs and knowledge gaps in aortic stenosis: A position paper from the Heart Valve Council of the French Society of Cardiology

Nowadays, valvular heart disease remains a significant challenge among cardiovascular diseases, affecting millions of people worldwide and exerting substantial pressure on healthcare systems. Within the spectrum of valvular heart disease, aortic stenosis is the most common valvular lesion in developed countries. Despite notable advances in understanding its pathophysiological processes, improved cardiovascular imaging techniques and expanding therapeutic options in recent years, there are still unmet needs and knowledge gaps regarding aortic stenosis pathophysiology, severity assessment, management and decision-making strategy. This review, prepared on behalf of the Heart Valve Council of the French Society of Cardiology, describes these gaps and future research perspectives to improve the outcome of patients with aortic stenosis.

Pathogenesis and Mechanism of Uremic Vascular Calcification

This review elucidates the modeling and mechanistic studies of vascular calcification in chronic kidney disease - mineral and bone disorder. In patients with chronic kidney disease, metabolic abnormalities in uremic toxins, including phosphate and indole sulfate, are closely associated with vascular calcification. Vitamin K, vascular circadian clock, and autophagy are also key factors involved in vascular calcification. Furthermore, communication between endothelial cells and smooth muscle cells also plays a pivotal role in the regulation of this process. Together, these factors accelerate vascular calcification progression and increase the risk of cardiovascular events. Therefore, timely intervention for vascular calcification is essential for patients with chronic kidney disease.

Editors' highlight picks from 2023 in ESC heart failure

Heart failure is a devastating syndrome affecting an increasingly high number of patients worldwide. Its aetiology and pathogenesis are complex with the involvement of factors ranging from the genetic material through valvular dysfunctions to numerous organs beyond the entire cardiovascular system. Based on continuous efforts of the heart failure scientific community we have witnessed major advances in many related disciplines during the last year. For example, epidemiological aspects-paving the road for improved risk prevention-have been thoroughly analysed for various geographical regions. Additionally, evidence-based approaches now allow the introduction of novel guideline recommended medical therapies (i.e. sodium-glucose transporter 2 inhibitors, and iron supplementation) while basic and translational research aim to explore additional molecular targets for future heart failure diagnostics and medications. All above aspects are addressed in this article, where a selection of articles published in the ESC Heart Failure journal in 2023 are highlighted. The editors are confident that the scientific contributions of ESC Heart Failure effectively served a highly relevant area of cardiovascular research last year.

CDK1 inhibition reduces osteogenesis in endothelial cells in vascular calcification

Vascular calcification is a severe complication of cardiovascular diseases. Previous studies demonstrated that endothelial lineage cells transitioned into osteoblast-like cells and contributed to vascular calcification. Here, we found that inhibition of cyclin-dependent kinase (CDK) prevented endothelial lineage cells from transitioning to osteoblast-like cells and reduced vascular calcification. We identified a robust induction of CDK1 in endothelial cells (ECs) in calcified arteries and showed that EC-specific gene deletion of CDK1 decreased the calcification. We found that limiting CDK1 induced E-twenty-six specific sequence variant 2 (ETV2), which was responsible for blocking endothelial lineage cells from undergoing osteoblast differentiation. We also found that inhibition of CDK1 reduced vascular calcification in a diabetic mouse model. Together, the results highlight the importance of CDK1 suppression and suggest CDK1 inhibition as a potential option for treating vascular calcification.

Predictive value of valvular calcification for the recurrence of persistent atrial fibrillation after radiofrequency catheter ablation

BACKGROUND

Valvular calcification (VC) is an independent risk factor for cardiovascular diseases. The relationship between VC and atrial fibrillation is not clear.

HYPOTHESIS

We treated the aortic valve, mitral valve, and tricuspid valve as a whole and considered the possible association between VC and recurrence of persistent atrial fibrillation (PsAF) after radiofrequency catheter ablation (RFCA).

METHODS

This study involved 2687 PsAF patients who underwent RFCA. Data were collected to explore the relationship between VC and outcome. VC was defined by echocardiography in aortic valve, mitral valve, or tricuspid valve. After 1 year follow-up, subgroup analysis, mixed model regression analysis, and score system analysis were performed. The external validation of 133 patients demonstrated the accuracy of this clinical prediction model.

RESULTS

Overall, 2687 inpatients were assigned to the recurrence group (n = 682) or the no recurrence group (n = 2005) with or without VC. Compared to patients with no recurrence, the incidence of VC was higher in recurrence patients. Recurrence was present in 18.5%, 34.9%, 39.3%, and 52.0% of the four groups, which met VC numbers of 0, 1, 2, and 3, respectively. After adjustment for potential confounding factors, VC was an independent risk factor for AF recurrence in several models. For multivariable logistic regression, a scoring system was established based on the regression coefficient. The receiver operating characteristic area of the scoring system was 0.787 in the external validation cohort.

CONCLUSIONS

VC was an independent risk factor for AF recurrence in PsAF after RFCA. The scoring system may be a useful clinical tool to assess AF recurrence.

Physicochemical understanding of biomineralization by molecular vibrational spectroscopy: From mechanism to nature

The process and mechanism of biomineralization and relevant physicochemical properties of mineral crystals are remarkably sophisticated multidisciplinary fields that include biology, chemistry, physics, and materials science. The components of the organic matter, structural construction of minerals, and related mechanical interaction, etc., could help to reveal the unique nature of the special mineralization process. Herein, the paper provides an overview of the biomineralization process from the perspective of molecular vibrational spectroscopy, including the physicochemical properties of biomineralized tissues, from physiological to applied mineralization. These physicochemical characteristics closely to the hierarchical mineralization process include biological crystal defects, chemical bonding, atomic doping, structural changes, and content changes in organic matter, along with the interface between biocrystals and organic matter as well as the specific mechanical effects for hardness and toughness. Based on those observations, the special physiological properties of mineralization for enamel and bone, as well as the possible mechanism of pathological mineralization and calcification such as atherosclerosis, tumor micro mineralization, and urolithiasis are also reviewed and discussed. Indeed, the clearly defined physicochemical properties of mineral crystals could pave the way for studies on the mechanisms and applications.

Aortic valve calcification is promoted by interleukin-8 and restricted through antagonizing CXC motif chemokine receptor 2

AIMS

Inflammatory cytokines play a critical role in the progression of calcific aortic valve disease (CAVD), for which there is currently no pharmacological treatment. The aim of this study was to test the hypothesis that interleukin-8 (IL-8), known to be involved in arterial calcification, also promotes aortic valve calcification (AVC) and to evaluate whether pharmacologically blocking the IL-8 receptor, CXC motif chemokine receptor 2 (CXCR2), could be effective in preventing AVC progression.

METHODS AND RESULTS

A cohort of 195 patients (median age 73, 74% men) diagnosed with aortic valve stenosis (severe in 16.9% of cases) were prospectively followed by CT for a median time of 2.6 years. A Cox proportional hazards regression analysis indicated that baseline IL-8 serum concentrations were associated with rapid progression of AVC, defined as an annualized change in the calcification score by CT ≥ 110 AU/year, after adjustment for age, gender, bicuspid anatomy, and baseline disease severity. In vitro, exposure of primary human aortic valvular interstitial cells (hVICs) to 15 pg/mL IL-8 induced a two-fold increase in inorganic phosphate (Pi)-induced calcification. IL-8 promoted NFκB pathway activation, MMP-12 expression, and elastin degradation in hVICs exposed to Pi. These effects were prevented by SCH527123, an antagonist of CXCR2. The expression of CXCR2 was confirmed in hVICs and samples of aortic valves isolated from patients with CAVD, in which the receptor was mainly found in calcified areas, along with MMP-12 and a degraded form of elastin. Finally, in a rat model of chronic kidney disease-associated CAVD, SCH527123 treatment (1 mg/kg/day given orally for 11 weeks) limited the decrease in aortic cusp separation, the increase in maximal velocity of the transaortic jet, and the increase in aortic mean pressure gradient measured by echocardiography, effects that were associated with a reduction in hydroxyapatite deposition and MMP-12 expression in the aortic valves.

CONCLUSION

Overall, these results highlight, for the first time, a significant role for IL-8 in the progression of CAVD by promoting calcification via a CXCR2- and MMP-12-dependent mechanism that leads to elastin degradation, and identify CXCR2 as a promising therapeutic target for the treatment of CAVD.

Focusing on the Native Matrix Proteins in Calcific Aortic Valve Stenosis

Calcific aortic valve stenosis (CAVS) is a widespread valvular heart disease affecting people in aging societies, primarily characterized by fibrosis, inflammation, and progressive calcification, leading to valve orifice stenosis. Understanding the factors associated with CAVS onset and progression is crucial to develop effective future pharmaceutical therapies. In CAVS, native extracellular matrix proteins modifications, play a significant role in calcification in vitro and in vivo. This work aimed to review the evidence on the alterations of structural native extracellular matrix proteins involved in calcification development during CAVS and highlight its link to deregulated biomechanical function.

Extracellular vesicles in atherosclerosis and vascular calcification: the versatile non-coding RNAs from endothelial cells and vascular smooth muscle cells

Atherosclerosis (AS) is characterized by the accumulation of lipids, fibrous elements, and calcification in the innermost layers of arteries. Vascular calcification (VC), the deposition of calcium and phosphate within the arterial wall, is an important characteristic of AS natural history. However, medial arterial calcification (MAC) differs from intimal calcification and cannot simply be explained as the consequence of AS. Endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are directly involved in AS and VC processes. Understanding the communication between ECs and VSMCs is critical in revealing mechanisms underlying AS and VC. Extracellular vesicles (EVs) are found as intercellular messengers in kinds of physiological processes and pathological progression. Non-coding RNAs (ncRNAs) encapsulated in EVs are involved in AS and VC, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs). The effects of ncRNAs have not been comprehensively understood, especially encapsulated in EVs. Some ncRNAs have demonstrated significant roles in AS and VC, but it remains unclear the functions of the majority ncRNAs detected in EVs. In this review, we summarize ncRNAs encapsulated in EC-EVs and VSMC-EVs, and the signaling pathways that are involved in AS and VC.

Differential expression profiles and functional analysis of long non-coding RNAs in calcific aortic valve disease

AIM

To evaluate the expression profile of long non-coding RNAs (lncRNAs) in calcific aortic valve disease (CAVD) and explore their potential mechanism of action.

METHODS

The gene expression profiles (GSE153555, GSE148219, GSE199718) were downloaded from the Gene Expression Omnibus (GEO) database and FastQC was run for quality control checks. After filtering and classifying candidate lncRNAs by differentially expressed genes (DEGs) and weighted co-expression networks (WGCNA) in GSE153555, we predicted the potential cis- or trans-regulatory target genes of differentially expressed lncRNAs (DELs) by using FEELnc and established the competitive endogenous RNA (ceRNA) network by miRanda, more over functional enrichment was analyzed using the ClusterProfiler package in R Bioconductor. The hub cis- or trans-regulatory genes were verified in GSE148219 and GSE199718 respectively.

RESULTS

There were 340 up-regulated lncRNAs identified in AS group compared with the control group (|log₂Fold Change| ≥ 1.0 and P_adj ≤ 0.05), and 460 down-regulated lncRNAs. Based on target gene prediction and co-expression network construction, twelve Long non-coding RNAs (CDKN2B-AS1, AC244453.2, APCDD1L-DT, SLC12A5-AS1, TGFB3, AC243829.4, MIR4435-2HG, FAM225A, BHLHE40-AS1, LINC01614, AL356417.2, LINC01150) were identified as the hub cis- or trans-regulatory genes in the pathogenesis of CAVD which were validated in GSE148219 and GSE19971. Additionally, we found that MIR4435-2HG was the top hub trans-acting lncRNA which also plays a crucial role by ceRNA pattern.

CONCLUSION

LncRNAs may play an important role in CAVD and may provide a new perspective on the pathogenesis, diagnosis, and treatment of this disease. Further studies are required to illuminate the underlying mechanisms and provide potential therapeutic targets.

Hypoxia-inducible factor activation promotes osteogenic transition of valve interstitial cells and accelerates aortic valve calcification in a mice model of chronic kidney disease

Introduction

Valve calcification (VC) is a widespread complication in chronic kidney disease (CKD) patients. VC is an active process with the involvement of in situ osteogenic transition of valve interstitial cells (VICs). VC is accompanied by the activation of hypoxia inducible factor (HIF) pathway, but the role of HIF activation in the calcification process remains undiscovered.

Methods and result

Using in vitro and in vivo approaches we addressed the role of HIF activation in osteogenic transition of VICs and CKD-associated VC. Elevation of osteogenic (Runx2, Sox9) and HIF activation markers (HIF-1α and HIF-2α) and VC occurred in adenine-induced CKD mice. High phosphate (Pi) induced upregulation of osteogenic (Runx2, alkaline-phosphatase, Sox9, osteocalcin) and hypoxia markers (HIF-1α, HIF-2α, Glut-1), and calcification in VICs. Down-regulation of HIF-1α and HIF-2α inhibited, whereas further activation of HIF pathway by hypoxic exposure (1% O₂) or hypoxia mimetics [desferrioxamine, CoCl₂, Daprodustat (DPD)] promoted Pi-induced calcification of VICs. Pi augmented the formation of reactive oxygen species (ROS) and decreased viability of VICs, whose effects were further exacerbated by hypoxia. N-acetyl cysteine inhibited Pi-induced ROS production, cell death and calcification under both normoxic and hypoxic conditions. DPD treatment corrected anemia but promoted aortic VC in the CKD mice model.

Discussion

HIF activation plays a fundamental role in Pi-induced osteogenic transition of VICs and CKD-induced VC. The cellular mechanism involves stabilization of HIF-1α and HIF-2α, increased ROS production and cell death. Targeting the HIF pathways may thus be investigated as a therapeutic approach to attenuate aortic VC.

Calcification of Synthetic Vascular Grafts: A Systematic Review

Objective

Calcification of vascular grafts, including polyethylene terephthalate (PET) and expanded polytetrafluoroethylene (ePTFE) grafts may contribute to graft failure, but is under reported. The aim of this study was to review the literature to assess whether vascular graft calcification is deleterious to vascular graft outcomes.

Data sources

The Medline and Embase databases were searched.

Review methods

A systematic literature search according to PRISMA Guidelines was performed using a combined search strategy of MeSH terms. The MeSH terms used were "calcification, physiologic", "calcinosis", "vascular grafting", "blood vessel prosthesis", "polyethylene terephthalates", and "polytetrafluoroethylene".

Results

The systematic search identified 17 cases of PET graft calcification and 73 cases of ePTFE graft calcification over a 35 year period. All cases of PET graft calcification were reported in grafts explanted for graft failure. The majority of cases of ePTFE graft calcification were unexpectedly noted in grafts used during cardiovascular procedures and subsequently removed.

Conclusion

Calcification of synthetic vascular grafts is under reported but can compromise the long term performance of the grafts. More data, including specific analysis of radiological findings as well as explant analysis are needed to obtain a more sensitive and specific analysis of the prevalence and incidence of vascular graft calcification and the impact of calcification on synthetic graft outcomes.

Prosthetic vascular grafts engineered to combat calcification: Progress and future directions

Calcification in prosthetic vascular conduits is a major challenge in cardiac and vascular surgery that compromises the long-term performance of these devices. Significant research efforts have been made to understand the etiology of calcification in the cardiovascular system and to combat calcification in various cardiovascular devices. Novel biomaterial design and tissue engineering strategies have shown promise in preventing or delaying calcification in prosthetic vascular grafts. In this review, we highlight recent advancements in the development of acellular prosthetic vascular grafts with preclinical success in attenuating calcification through advanced biomaterial design. We also discuss the mechanisms of action involved in the designs that will contribute to the further understanding of cardiovascular calcification. Lastly, recent insights into the etiology of vascular calcification will guide the design of future prosthetic vascular grafts with greater potential for translational success.

Cardiac valve calcification as a predictor of cardiovascular outcomes in peritoneal dialysis patients: an inverse probability of treatment weighting analysis

BACKGROUND

Cardiovascular events (CVE) are the leading cause of death in peritoneal dialysis (PD) patients. The predictive value of cardiac valve calcification (CVC) for CVE in dialysis patients remains controversial. In particular, such studies are limited in PD patients. We aimed to examine the predictive role of CVC for CVE and cardiovascular mortality in PD patients.

METHODS

A retrospective analysis was performed on patients who initiated PD in our hospital. According to the result of echocardiography, patients were divided into CVC group and non-CVC group. The differences in baseline demographic characteristics, biochemical variables, comorbidities, and clinical outcomes between the two groups were compared. Kaplan-Meier method was used to obtain survival curves. The Cox regression model was used to evaluate the influence of CVC for cardiovascular outcomes. The inverse probability of treatment weighting (IPTW) was used to eliminate influence of the confounders in the groups.

RESULTS

458 peritoneal dialysis patients were enrolled in this study. 77 patients were in CVC group and 381 patients in non-CVC group. The average follow-up time was (32 ± 21) months. At baseline, the absolute standardized difference (ASD) of age, BMI, history of CVE, diabetes, LVEF, LVMI, albumin, calcium, phosphorus, triglycerides, hsCRP, urine volume, Kt/V, statins and vitamin D intake rate were greater than 0.1 between the two groups. All of ASD dropped to less than 0.1 after IPTW, which meant that the balance had been reached between the two groups. Multivariable logistic analysis showed that advanced age, diabetes, and hyperphosphatemia were associated with CVC. The Kaplan-Meier survival curve showed the cumulative CVE-free survival rate and cardiovascular survival rate of CVC group were significantly lower than that of non-CVC group before and after IPTW (log-rank P < 0.05). After IPTW was used to eliminate the effect of confounders, multivariate Cox regression analysis still showed CVC was an independent risk factor for CVE (HR = 2.383, 95% CI 1.331~4.264, P = 0.003) and cardiovascular mortality (HR = 2.347, 95% CI 1.211~4.548, P = 0.012) in PD patients.

CONCLUSION

The prevalence of CVC is high in peritoneal dialysis patients. CVC is an independent risk factor for CVE and cardiovascular mortality in peritoneal dialysis patients.

Serum biomarkers for arterial calcification in humans: A systematic review

Aim

To clarify the role of mediators of ectopic mineralization as biomarkers for arterial calcifications.

Methods

MEDLINE and Embase were searched for relevant literature, until January 4th 2022. The investigated biomarkers were: calcium, phosphate, parathyroid hormone, vitamin D, pyrophosphate, osteoprotegerin, receptor activator of nuclear factor-kappa B ligand (RANKL), fibroblast growth factor-23 (FGF-23), Klotho, osteopontin, osteocalcin, Matrix Gla protein (MGP) and its inactive forms and vitamin K. Studies solely performed in patients with kidney insufficiency or diabetes mellitus were excluded.

Results

After screening of 8985 articles, a total of 129 articles were included in this systematic review. For all biomarkers included in this review, the results were variable and more than half of the studies for each specific biomarker had a non-significant result. Also, the overall quality of the included studies was low, partly as a result of the mostly cross-sectional study designs. The largest body of evidence is available for phosphate, osteopontin and FGF-23, as a little over half of the studies showed a significant, positive association. Firm statements for these biomarkers cannot be drawn, as the number of studies was limited and hampered by residual confounding or had non-significant results. The associations of the other mediators of ectopic mineralization with arterial calcifications were not clear.

Conclusion

Associations between biomarkers of ectopic mineralization and arterial calcification are variable in the published literature. Future longitudinal studies differentiating medial and intimal calcification could add to the knowledge of biomarkers and mechanisms of arterial calcifications.

•

We researched the association between biomarkers and arterial calcifications.

•

This review focused on biomarkers of bone metabolism and Matrix Gla protein.

•

Associations between biomarkers and arterial calcification are variable.

•

Future studies should differentiate between medial and intimal calcifications.

Genetically predicted phosphate and cardiovascular disease: A Mendelian randomization study

Background

Extensive epidemiological studies have highlighted the correlation between serum phosphate and cardiovascular diseases. The present study aims to determine whether genetically predicted serum phosphate is causally associated with the distinct subtypes of cardiovascular events through the use of Mendelian randomization (MR) analysis.

Methods

Independent and strongly correlated single-nucleotide polymorphisms (SNPs) for serum phosphate were extracted from publicly available genome-wide association studies. Summary statistics of cardiovascular diseases were derived from large-scale consortiums, including HERMES and FinnGen biobank. MR-Egger, weighted median, inverse variance weighted, pleiotropy residual sum and outlier (MR-PRESSO) methods and MR using robust adjusted profile score (MR-RAPS) were employed to analyze causality. The sensitivity analyses comprised heterogeneity, horizontal pleiotropy, and leave-one-out approaches; these were used to ensure the stability of the results.

Results

Our study demonstrated that increased genetically predicted serum phosphate is causally associated with a higher risk of valvular heart disease (VHD) [For VHD including rheumatic fever: odds ratio (OR) = 2.45; 95% confidence interval (CI), 1.52-3.94; p = 0.0002; for non-rheumatic VHD: OR = 6.58; 95% CI, 2.50-17.32; p = 0.0001]. However, no causal association was detected between serum phosphate and other common cardiovascular diseases (including coronary heart disease, heart failure, atrial fibrillation, and essential hypertension).

Conclusions

The results indicate strong causality between serum phosphate and valvular heart disease. Serum phosphate-lowering therapy within the physiological range may represent a novel therapeutic method for valvular heart disease.

Association of serum levels of calcium, phosphate, and vitamin D with risk of developing aortic stenosis: the UK Biobank cohort

AIMS

This study was aimed to investigate the associations of serum calcium, phosphate, and vitamin D levels with the risk of developing aortic stenosis (AS).

METHODS AND RESULTS

We included 296 415 participants who were free of prior diagnosis of any valvular heart disease from the UK Biobank. Serum levels of phosphate, calcium, and vitamin D were measured. Incidental AS was determined by the records of hospital data. Cox regression was used to examine the association of serum mineral levels with incidental AS after adjustment for potential confounders. The mean age was 56.4 years (SD 8.14) and 53.3% of participants were women. During an average follow-up of 8.1 years, 1232 individuals developed AS. After adjustment, each 0.5-unit increase in serum phosphate level was associated with a 50% increase of AS risk (hazard ratio 1.50, 95% confidence interval 1.26-1.80). We observed no association of serum calcium and vitamin D levels with AS.

CONCLUSION

Increased serum phosphate level, but not calcium or vitamin D, was associated with a higher risk of incident AS, this association did not differed substantially between patients with and without decreased kidney function. This finding implied that phosphate may be a potential interventional target for AS.

Conductance Artery Wall Layers and Their Respective Roles in the Clearance Functions

Evolutionary organization of the arterial wall into layers occurred concomitantly with the emergence of a highly muscularized, pressurized arterial system that facilitates outward hydraulic conductance and mass transport of soluble substances across the arterial wall. Although colliding circulating cells disperse potential energy within the arterial wall, the different layers counteract this effect: (1) the endothelium ensures a partial barrier function; (2) the media comprises smooth muscle cells capable of endocytosis/phagocytosis; (3) the outer adventitia and perivascular adipocytic tissue are the final receptacles of convected substances. While the endothelium forms a physical and a biochemical barrier, the medial layer is avascular, relying on the specific permeability properties of the endothelium for metabolic support. Different components of the media interact with convected molecules: medial smooth muscle cells take up numerous molecules via scavenger receptors and are capable of phagocytosis of macro/micro particles. The outer layers-the highly microvascularized innervated adventitia and perivascular adipose tissue-are also involved in the clearance functions of the media: the adventitia is the seat of immune response development, inward angiogenesis, macromolecular lymphatic drainage, and neuronal stimulation. Consequently, the clearance functions of the arterial wall are physiologically essential, but also may favor the development of arterial wall pathologies. This review describes how the walls of large conductance arteries have acquired physiological clearance functions, how this is determined by the attributes of the endothelial barrier, governed by endocytic and phagocytic capacities of smooth muscle cells, impacting adventitial functions, and the role of these clearance functions in arterial wall diseases.

The mechanistic pathways of oxidative stress in aortic stenosis and clinical implications

Despite the elucidation of the pathways behind the development of aortic stenosis (AS), there remains no effective medical treatment to slow or reverse its progress. Instead, the gold standard of care in severe or symptomatic AS is replacement of the aortic valve. Oxidative stress is implicated, both directly as well as indirectly, in lipid infiltration, inflammation and fibro-calcification, all of which are key processes underlying the pathophysiology of degenerative AS. This culminates in the breakdown of the extracellular matrix, differentiation of the valvular interstitial cells into an osteogenic phenotype, and finally, calcium deposition as well as thickening of the aortic valve. Oxidative stress is thus a promising and potential therapeutic target for the treatment of AS. Several studies focusing on the mitigation of oxidative stress in the context of AS have shown some success in animal and in vitro models, however similar benefits have yet to be seen in clinical trials. Statin therapy, once thought to be the key to the treatment of AS, has yielded disappointing results, however newer lipid lowering therapies may hold some promise. Other potential therapies, such as manipulation of microRNAs, blockade of the renin-angiotensin-aldosterone system and the use of dipeptidylpeptidase-4 inhibitors will also be reviewed.

PTP1B Inhibition Improves Mitochondrial Dynamics to Alleviate Calcific Aortic Valve Disease Via Regulating OPA1 Homeostasis

•

Increased PTP1B was observed in the human calcified aortic valve leaflets and VIC osteogenesis, which indicated a novel association of PTP1B with aortic valve calcification.

•

MSI-1436, a specific pharmacological PTP1B inhibitor, attenuated osteogenic and myofibrogenic differentiation of VICs, which coincided with preventing aortic valve fibrocalcific disease in a diet-induced mouse model of CAVD.

•

Treatment of CAVD with PTP1B inhibitor mitigated the disorder of aortic jet velocity and mean gradient in vivo.

•

PTP1B inhibition preserved the mitochondrial biogenesis and function in VIC osteogenesis via regulating OPA1 homeostasis.

There are currently no pharmacological therapies for calcific aortic valve disease (CAVD). Here, we evaluated the role of protein tyrosine phosphatase 1B (PTP1B) inhibition in CAVD. Up-regulation of PTP1B was critically involved in calcified human aortic valve, and PTP1B inhibition had beneficial effects in preventing fibrocalcific response in valvular interstitial cells and LDLR^−/− mice. In addition, we reported a novel function of PTP1B in regulating mitochondrial homeostasis by interacting with the OPA1 isoform transition in valvular interstitial cell osteogenesis. Thus, these findings have identified PTP1B as a potential target for preventing aortic valve calcification in patients with CAVD.

Molecular Probes, Chemosensors, and Nanosensors for Optical Detection of Biorelevant Molecules and Ions in Aqueous Media and Biofluids

Synthetic molecular probes, chemosensors, and nanosensors used in combination with innovative assay protocols hold great potential for the development of robust, low-cost, and fast-responding sensors that are applicable in biofluids (urine, blood, and saliva). Particularly, the development of sensors for metabolites, neurotransmitters, drugs, and inorganic ions is highly desirable due to a lack of suitable biosensors. In addition, the monitoring and analysis of metabolic and signaling networks in cells and organisms by optical probes and chemosensors is becoming increasingly important in molecular biology and medicine. Thus, new perspectives for personalized diagnostics, theranostics, and biochemical/medical research will be unlocked when standing limitations of artificial binders and receptors are overcome. In this review, we survey synthetic sensing systems that have promising (future) application potential for the detection of small molecules, cations, and anions in aqueous media and biofluids. Special attention was given to sensing systems that provide a readily measurable optical signal through dynamic covalent chemistry, supramolecular host-guest interactions, or nanoparticles featuring plasmonic effects. This review shall also enable the reader to evaluate the current performance of molecular probes, chemosensors, and nanosensors in terms of sensitivity and selectivity with respect to practical requirement, and thereby inspiring new ideas for the development of further advanced systems.

Serum Calcification Propensity and Calcification of the Abdominal Aorta in Patients With Primary Aldosteronism

Patients with primary aldosteronism (PA) are more susceptible to cardiovascular disease and mortality than patients with primary hypertension. This is mostly attributed to excess production of aldosterone and its effects on the development of vascular injury. A novel functional test (T₅₀) measures serum calcification propensity. Lower T₅₀-values predict higher cardiovascular risk. We investigated serum calcification propensity and vascular calcification in PA and resistant hypertension (RH). T₅₀ measurement was performed in patients with PA (n = 66) and RH (n = 28) at baseline and after 403 (279–640) and 389 (277–527) days of treatment. No significant differences in T₅₀-values were observed between the groups (371 ± 65 and 382 ± 44 min, in PA and RH group, respectively, p > 0.05). However, higher aldosterone-to-renin ratios were associated with lower T₅₀-values in PA-patients (r −0.282, p < 0.05). Furthermore, lower T₅₀-values were associated with increased abdominal aortic calcification measured by Agatston score in PA (r −0.534, p < 0.05). In both, PA and RH, higher atherosclerotic cardiovascular disease (ACSVD) scores (r −0.403, p < 0.05) and lower HDL (r 0.469, p < 0.05) was related to lower T₅₀-values in a linear regression model. Adrenalectomy or medical treatment did not increase T₅₀-values. In comparison to patients with stable T₅₀-values, PA patients with a decrease in T₅₀ after intervention had higher serum calcium concentrations at baseline (2.24 ± 0.11 vs. 2.37 ± 0.10 mmol/l, p < 0.05). This decline of T₅₀-values at follow-up was also associated with a decrease in serum magnesium (−0.03 ± 0.03 mmol/l, p < 0.05) and an increase in phosphate concentrations (0.11 ± 0.11 mmol/l, p < 0.05). Resistant hypertension patients with a decrease in T₅₀-values at follow-up had a significantly lower eGFR at baseline. In summary, these data demonstrate an association between a high aldosterone-to-renin ratio and low T₅₀-values in PA. Moreover, lower T₅₀-values are associated with higher ACSVD scores and more pronounced vascular calcification in PA. Thus, serum calcification propensity may be a novel modifiable risk factor in PA.

Associations of Social Vulnerability Index With Pathologic Myocardial Findings at Autopsy

Background: Social vulnerability is an important determinant of cardiovascular health. Prior investigations have shown strong associations of social determinants of health with cardiovascular risk factors, imaging findings, and clinical events. However, limited data exist regarding the potential role of social vulnerability and related physiologic stressors on tissue-level pathology. Methods: We analyzed clinical data and linked autopsy reports from 853 decedent individuals who underwent autopsy from 4/6/2002 to 4/1/2021 at a large urban medical center. The mean age at death was 62.9 (SD = 15.6) and 49% of decedent individuals were men. The primary exposure was census-tract level composite social vulnerability index based on the Centers for Disease Control and Prevention Social Vulnerability Index (SVI). Individuals were geocoded to census tracts and assigned SVI accordingly. Four myocardial tissue-level outcomes from autopsy were recorded as present or absent: any coronary atherosclerosis, severe/obstructive coronary atherosclerosis, myocardial fibrosis, and/or myopericardial inflammation. Multivariable-adjusted logistic regression models were constructed with SVI as the primary exposure and covariates including age, sex, race, body mass index (BMI), diabetes, and hypertension. Additional analyses were performed stratified by clinical diagnoses of heart failure (HF) and coronary artery disease (CAD). Results: In the overall cohort, SVI was not associated with outcomes on cardiac pathology in multivariable-adjusted models. However, in stratified multivariable-adjusted analyses, higher SVI (higher social vulnerability) was associated with a higher odds of myocardial fibrosis among individuals without clinical diagnoses of HF. Conclusions: Higher indices of social vulnerability are associated with a higher odds of myocardial fibrosis at autopsy among individuals without known clinical diagnoses of HF. Potential pathophysiological mechanisms and implications for prevention/treatment of myocardial dysfunction require further study.

Calcific aortic valve disease: from molecular and cellular mechanisms to medical therapy

Calcific aortic valve disease (CAVD) is a highly prevalent condition that comprises a disease continuum, ranging from microscopic changes to profound fibro-calcific leaflet remodelling, culminating in aortic stenosis, heart failure, and ultimately premature death. Traditional risk factors, such as hypercholesterolaemia and (systolic) hypertension, are shared among atherosclerotic cardiovascular disease and CAVD, yet the molecular and cellular mechanisms differ markedly. Statin-induced low-density lipoprotein cholesterol lowering, a remedy highly effective for secondary prevention of atherosclerotic cardiovascular disease, consistently failed to impact CAVD progression or to improve patient outcomes. However, recently completed phase II trials provide hope that pharmaceutical tactics directed at other targets implicated in CAVD pathogenesis offer an avenue to alter the course of the disease non-invasively. Herein, we delineate key players of CAVD pathobiology, outline mechanisms that entail compromised endothelial barrier function, and promote lipid homing, immune-cell infiltration, and deranged phospho-calcium metabolism that collectively perpetuate a pro-inflammatory/pro-osteogenic milieu in which valvular interstitial cells increasingly adopt myofibro-/osteoblast-like properties, thereby fostering fibro-calcific leaflet remodelling and eventually resulting in left ventricular outflow obstruction. We provide a glimpse into the most promising targets on the horizon, including lipoprotein(a), mineral-binding matrix Gla protein, soluble guanylate cyclase, dipeptidyl peptidase-4 as well as candidates involved in regulating phospho-calcium metabolism and valvular angiotensin II synthesis and ultimately discuss their potential for a future therapy of this insidious disease.