Calcium Markers Research Articles

PIVKA-II but not dp-ucMGP is associated with aortic calcification in chronic kidney disease

BackgroundPatients with chronic kidney disease (CKD) are susceptible to vascular calcification and vitamin K deficiency. Matrix gla protein (MGP) is a potent inhibitor of calcification requiring vitamin K for activation. Inactive MGP, i.e. dephosphorylated uncarboxylated MGP (dp-ucMGP), is frequently elevated in CKD along with protein induced by vitamin K absence (PIVKA-II). We investigated whether dp-ucMGP and PIVKA-II are useful markers of aortic calcification in CKD.MethodsPatients with normal or reduced kidney function underwent a non-contrast computed tomography scan of the entire aorta with subsequent blinded standard calcification scoring of the aortic wall ad modum Agatston. Blood samples were analyzed for plasma concentrations of dp-ucMGP and PIVKA-II.Results141 patients (104 with CKD stage 3–5) were included. In patients with/without CKD median (interquartile range) were dp-ucMGP 543 (503–744)/1078 (835–1682) pmol/l (P < 0.01); PIVKA-II 19.3 (16.3–23.5)/21.8 (17.2–36.8) ng/ml (P = 0.33) and aortic Agatston scores 1644 (729–4138)/7172 (2834–15360) (P < 0.01). Agatston score was positively associated with PIVKA-II (β = 0.71, P = 0.014, r2 = 0.04) and tended to be so with dp-ucMGP (β = 0.44, P = 0.08, r2 = 0.02). Age, estimated glomerular filtration rate (eGFR) and smoking status were also associated with Agatston score and remained so, along with PIVKA-II, when adjusted for potential confounders. However, the association between age and aortic Agatston score was stronger than for PIVKA-II, eGFR and smoking-status.ConclusionVitamin K deficiency, as estimated through PIVKA-II, but not dp-ucMGP, is weakly associated with aortic Agatston score. Yet, as markers of aortic calcification, both were outperformed substantially by age, and neither surpassed smoking nor eGFR.ClinicalTrials.gov identifierNCT04114695.

Transglutaminase 2 regulates endothelial cell calcification via IL-6-mediated autophagy.

Endothelial cell (EC) calcification is an important marker of atherosclerotic calcification. ECs play a critical role not only in atherogenesis but also in intimal calcification, as they have been postulated to serve as a source of osteoprogenitor cells that initiate this process. While the role of transglutaminase 2 (TG2) in cellular differentiation, survival, apoptosis, autophagy, and cell adhesion is well established, the mechanism underlying the TG2-mediated regulation of EC calcification is yet to be fully elucidated. The TG2 gene was overexpressed or silenced by using siRNA and recombinant adenovirus. RT-PCR and WB were used to analyze the relative expression of target genes and proteins. 5-BP method analyzed TG2 activity. mCherry-eGFP-LC3 adenovirus and transmission electron microscopy analyzed EC autophagy level. Calcium concentrations were measured by using a calcium colorimetric assay kit. Alizarin red S staining assay analyzed EC calcification level. Elisa analyzed IL-6 level. Establishing EC calcification model by using a calcification medium (CM). Our findings demonstrated that CM increased TG2 activity and expression, which activated the NF-κB signaling pathway, and induced IL-6 autocrine signaling in ECs. Furthermore, IL-6 activated the JAK2/STAT3 signaling pathway to suppress cell autophagy and promoted ECs calcification. ECs are not only critical for atherogenesis but also believed to be a source of osteoprogenitor cells that initiate intimal calcification. Previous research has shown that TG2 plays an important role in the development of VC, but the mechanism by which it exerts this effect is not yet fully understood. Our results demonstrated that TG2 forms complexes with NF-κB components inhibition of autophagy promoted endothelial cell calcification through EndMT. Therefore, our research investigated the molecular mechanism of EC calcification, which can provide new insights into the pathogenesis of atherosclerosis.

Niclosamide attenuates calcification in human heart valvular interstitial cells through inhibition of the AMPK/mTOR signaling pathway

Calcific aortic valve disease (CAVD) is a considerable health burden with a lack of effective therapeutic options. There is an urgent need to develop interventions that inhibit the osteogenic transformation of valvular interstitial cells (VICs) and delay the calcification process. Niclosamide, an FDA-approved anti-helminthic drug, has emerged as a promising candidate that demonstrates a negative regulatory effect on porcine VICs calcification. However, its molecular mechanism in human VICs (hVICs) remains to be investigated. In this study, high-resolution mass spectrometry-based proteomics and phosphoproteomics were employed, and 8373 proteins and 3697 phosphosites were identified in hVICs treated with a pro-calcifying medium and niclosamide. The quantitative proteomic and phosphoproteomic analysis resulted in the identification of calcification markers and osteogenesis-associated proteins. Bioinformatic analysis of the protein–protein interaction network and affected kinase prediction revealed that the AMPK/mTOR/p70S6K signaling cascade was altered upon calcific induction and niclosamide treatment. Further validation indicated that niclosamide inhibited the calcification of hVICs by targeting the mammalian target of the rapamycin (mTOR) signaling pathway. This study provides the first evidence that niclosamide could prevent osteoblastic differentiation in hVICs partially through the inhibition of the AMPK/mTOR/p70S6k signaling pathway, thereby mitigating hVICs calcification. These findings present a foundation for potential therapeutic strategies to impede the progression of CAVD and provide valuable insights into the pharmacological effects of niclosamide on human VICs.

Early vascular aging in chronic kidney disease: focus on microvascular maintenance, senescence signature and potential therapeutics

Chronic kidney disease (CKD) is a strong risk factor for cardiovascular mortality and morbidity. We hypothesized that a senescent phenotype instigated by uremic toxins could account for early vascular aging (EVA) and vascular dysfunctions of microvasculature in end stage kidney disease (ESKD) patients which ultimately lead to increased cardiovascular complication. To test this hypothesis, we utilized both in vivo, and ex vivo approaches to study endothelial and smooth muscle function and structure, and characterized markers related to EVA in 82 ESKD patients (eGFR <15 ml/min) and 70 non-CKD controls. In vivo measurement revealed no major difference in endothelial function between ESKD and control group, aside from higher stiffness detected in the microcirculation of ESKD participants. In contrast, ex vivo measurements revealed a notable change in the contribution of endothelium-derived factors and increased stiffness in ESKD patients vs. controls. In support, we demonstrated that ex vivo exposure of arteries to uremic toxins such as Trimethylamine N-oxide, Phenylacetylglutamine, or extracellular vesicles from CKD patients impaired endothelial function via diminishing the contribution of endothelium-derived relaxing factors such as nitric oxide and endothelium derived hyperpolarizing factor. Uremic arteries displayed elevated expression of senescence markers (p21CIP1, p16INK4a, and SA-β-gal), calcification marker (RUNX2), and reduced expression of Ki67, sirtuin1, Nrf2, and MHY11 markers, indicating the accumulation of senescent cells and EVA phenotype. Correspondingly, treating uremic vessel rings ex vivo with senolytic agents (Dasatinib + Quercetin) effectively reduced the senescence-associated secretory phenotype and changed the origin of extracellular vesicles. Notably, sex differences exist for certain abnormalities suggesting the importance of biological sex in the pathogenesis of vascular complications. In conclusion, the uremic microvasculature is characterized by a “senescence signature”, which may contribute to EVA and cardiovascular complications in ESKD patients and could be alleviated by treatment with senolytic agents.

Teriparatide administration is osteoanabolic but does not impact atherosclerotic plaque calcification and progression in a mouse model of menopause

Menopause exacerbates osteoporosis and increases the risk of atherosclerotic plaque rupture, leading to cardiovascular mortality. Osteoporotic women are increasingly treated with teriparatide (TPTD, 1–34 parathyroid hormone), one of the few treatments that stimulate bone formation. Despite the fact that atherosclerotic plaque calcification is a hallmark of plaque development, the impact of TPTD administration on plaque calcification remain unclear. In this context, we sought to determine the effects of TPTD administration on atherosclerosis in ovariectomized (OVX) apolipoprotein E deficient mice (ApoE−/−), as a model of postmenopausal osteoporosis. OVX ApoE−/− mice, fed a high fat, high cholesterol diet to induce atherosclerosis, received either vehicle or TPTD daily injections (40 μg/kg/d) for 4 or 10 weeks, at which points plaques are respectively weakly and heavily calcified. After sacrifice, bone remodeling was evaluated by serum markers and bone histomorphometry. Bone architectural parameters were measured by μCT. Aortic plaques were analyzed histologically, and their calcification with von Kossa staining and the calcium tracer Osteosense. Plaque inflammation and calcification markers were measured by RT-qPCR. Intermittent TPTD increased bone volume in OVX mice, due to a higher stimulation of bone formation relatively to bone resorption. These effects were not accompanied by changes in serum levels of cholesterol, triglycerides, glucose or insulin. TPTD neither significantly affected aortic plaque size, inflammation, and calcification, even if it slightly increased vascular smooth muscle cell transdifferentiation into calcifying cells. In conclusion, TPTD exhibits osteoanabolic effects in OVX ApoE−/− mice, without significantly influencing atherosclerotic plaque progression or calcification in the short term.

Calcific aortic valve disease-associated long noncoding RNA H19 promotes the osteogenic transition of valvular interstitial cells via the JAG1/NOTCH1 axis

Abstract Background Calcific aortic valve disease (CAVD) is the most prevalent valvular heart disease causing tremendous suffering globally. The osteogenic differentiation of the valvular interstitial cells (VICs) is a key process in the pathogenesis of CAVD leading to calcification and stiffening. Here, we focus on the contribution of long noncoding RNA H19 in the osteogenic differentiation of VICs promoting CAVD. Methods and results A human lncRNA array performed in AVS patients with coronary artery disease (CAD) revealed the differential expression of lncRNA H19. For the experiments in this study, loss of function (LOF) was performed in primary VICs isolated from the aortic valves of patients with CAVD, and commercially-available VICs. Therefore, H19 expression was effectively downregulated via RNAi. Subsequent gene expression analysis via RT-qPCR revealed that the expression of calcification markers RUNX2 and BMP2, as well as the expression of the H19 downstream targets JAG1 and NOTCH1 were unchanged after the H19 knockdown alone. Then, the VICs were additionally treated with osteogenic medium (OM) and procalcifying medium (PCM) for 7 d to induce the calcification of the cells. In the OM, inorganic phosphate is generated in an alkaline phosphatase (ALPL)-dependent manner and integrated into newly formed hydroxyapatite crystals, thus promoting cellular calcification. PCM contains inorganic phosphate to form hydroxyapatite crystals and is therefore not ALPL-dependent. Gene expression analysis via RT-qPCR and protein analysis via immunofluorescence revealed that the calcification markers BMP2 and RUNX2 were upregulated after H19 knockdown and calcification induction. This indicates that H19 regulates the expression of calcification makers promoting cellular calcification. Furthermore, RT-qPCR and immunoblotting revealed the differential expression of several potential H19 downstream targets, namely JAG1, NOTCH1, and STAT3. The analysis showed that the potential downstream targets were upregulated after H19 knockdown and calcification treatment hinting at the involvement of the NOTCH1 or STAT3 pathway in the pathogenesis of CAVD. Moreover, an Alizarin Red S staining of calcified nodules revealed reduced calcification after H19 knockdown and calcification treatment for 21 d. This demonstrates that H19 also regulates a late-stage event in the cellular calcification of VICs. Conclusion Our study showed that H19 regulates calcification marker expression and the expression of potential downstream targets JAG1, NOTCH1, and STAT3 both in healthy and AVS patient VICs. This hints at the involvement of the H19/JAG1/NOTCH1 pathway in the calcification of VICs, which might play a critical role in the pathogenesis of CAVD.

Aortic valve disease augments vesicular microRNA-145-5p to regulate the calcification of valvular interstitial cells via cellular crosstalk

Abstract Rationale: Aortic valve stenosis (AVS) is a major contributor to cardiovascular death in the elderly population worldwide. MicroRNAs (miRNAs) are highly dysregulated in patients with AVS undergoing surgical aortic valve replacement (SAVR). However, miRNA-dependent mechanisms regulating inflammation and calcification or miRNA-mediated cell-cell crossstalk during the pathogenesis of AVS are still poorly understood. Here, we explored the role of extracellular vesicles (EV)-associated miR-145-5p, which we showed to be highly upregulated upon valvular calcification in AVS in mice and humans. Methods Human TaqMan miRNA arrays identified dysregulated miRNAs in aortic valve tissue explants from AVS patients compared to non-calcified valvular tissue explants of patients undergoing SAVR. Echocardiographic parameters were measured in association with the quantification of dysregulated miRNAs in a murine AVS model. In vitro calcification experiments were performed to explore the effects of EV-miR-145-5p on calcification and crosstalk in valvular cells. To dissect molecular miRNA signatures and their effect on signaling pathways, integrated OMICS analyses were performed. RNA sequencing (RNA-seq), high-throughput transcription factor (TF) and proteome arrays showed that a number of genes, miRNAs, TFs, and proteins are crucial for calcification and apoptosis, which are involved in the pathogenesis of AVS. Results Among several miRNAs dysregulated in valve explants of AVS patients, miR-145-5p was the most highly gender-independently dysregulated miRNA (AUC, 0.780, p-value, 0.01). MiRNA arrays utilizing patient-derived- and murine aortic-stenosis samples demonstrated that the expression of miR-145-5p is significantly upregulated and correlates positively with cardiac function based on echocardiography. In vitro experiments confirmed that miR-145-5p is encapsulated into EVs and shuttled into valvular interstitial cells. Based on the integrated OMICs results, miR-145-5p interrelates with markers of inflammation, calcification, and apoptosis. In vitro calcification experiments demonstrated that miR-145-5p regulates the ALPL gene, a hallmark of calcification in vascular and valvular cells. EV-mediated shuttling of miR-145-5p suppressed the expression of ZEB2, a negative regulator of the ALPL gene, by binding to its 3' untranslated region to inhibit its translation, thereby diminishing the calcification of target valvular interstitial cells. Conclusion Elevated levels of pro-calcific and pro-apoptotic EV-associated miR-145-5p contribute to the progression of AVS via the ZEB2-ALPL axis, which could potentially be therapeutically targeted to minimize the burden of AVS.

Lipoprotein(a) as a predictive marker of coronary artery calcification (CAC). The results from the STAR-Lp(a) cohort study.

Abstract Background Lipoprotein(a) [Lp(a)] concentration is an independent risk factor for cardiovascular disease, including atherosclerosis. Purpose The aim of the study was to assess the relationship between the elevated Lp(a) levels, and the risk of developing atherosclerosis assessed using coronary artery calcium (CAC) score. Methods The analysis was conducted among 553 primary prevention patients (65.7% women, the average age was 65.8±10.1 years) from the outpatient specialist care who underwent coronary computed tomographic angiography (CTA). This group accounted for 22.3% of all patients (n=2475) included in the registry. Lp(a) levels were assessed in three groups: &amp;lt;30 mg/dL (&amp;lt;75 nmol/l) (normal level), 30-50 mg/dL (75-125 nmol/l) (moderate cardiovascular risk) and &amp;gt;50 (&amp;gt;125 nmol/l) (high cardiovascular risk). Patients were divided into groups: with normal CAC score (CAC=0), with CAC 1-100 (presence of atherosclerotic), and those with CAC&amp;gt;100 (advanced atherosclerosis). Statistical analysis was performed using STATISTICA 13.1. Quantitative variables were known by providing descriptive statistics (mean and standard deviation [SD]). The chi-square test was used to assess the relationship between quantitative variables and Mann-Whitney and Kruskal Wallis in the case of qualitative variables. Pearson's correlation coefficient was used to measure correlation. To determine the effect of factors on the probability of occurrence CAC=0 a multivariate logistic regression model was built. P&amp;lt;0.05 was judged as significant. Results Positive significant correlation between CAC score and age was revealed (r=0.266, p&amp;lt;0.001). An analogous relationship was observed regarding to glucose level (r=-0.123, p=0.012). This was not observed for Lp(a). However, we showed a significant relationship between the level of Lp(a) and CAC score (r=0.113, p=0.009) (Fig. 1). Lp(a) levels increased with the CAC score increase. For every 10 mg/dL (25 nmol/l) of Lp(a), CAC score increases by 15.7±0.57 (p=0.006). The mean CAC among patients with normal Lp(a) level was 203.1 (±412.6) and respectively 206.6 (±460.1) in those with moderate cardiovascular risk and 335.6 (±784.9) for people with high risk (p=0.183). In the regression model the factors determining the absence of atherosclerosis (CAC=0; "power of zero") included female gender (OR = 4.05; 95CI: 2.48-6.59), age under 65 (OR = 0.31; 95CI: 0.07-1.34 for aged 40-65), and Lp(A)≤50 mg/dl (≤125 nmol/l) (OR=2.26; 95CI: 1.12-4.61). People with hypertension had a significantly lower odds of CAC=0 (OR=0.58; 95CI: 0.38-0.89). Conclusions The study showed a significant linear relationship between increased Lp(a) levels, and the progression of atherosclerosis expressed by the CAC score. Results confirm some existing recommendations that if an elevated Lp(a) level is found in a patient for primary prevention, a CT scan of the coronary arteries with assessment of the CAC score should be considered for more appropriate risk stratification.

Alleviating vascular calcification with Bushen Huoxue formula in rats with chronic kidney disease by inhibiting the PTEN/PI3K/AKT signaling pathway through exosomal microRNA-32.

Vascular calcification (VC) significantly raises cardiovascular mortality in chronic kidney disease (CKD) patients. VC is characterized by the phenotypic transformation of vascular smooth muscle cells (VSMCs) to osteoblast-like cells, mediated by exosomes derived from calcified VSMCs and the exosomal microRNAs (miRNA) which may trigger some signals to recipient VSMCs. Bushen Huoxue (BSHX) formula has demonstrated its clinical efficacy in CKD and its protective role in CKD-VC rats has also been observed. However, little is known about its underlying mechanism. To establish a VC model, aortic VSMCs from rats were induced to osteogenic differentiation by high-level phosphate (HP) in vitro. The expression of exosome and calcification makers were analyzed by western blot, including CD9, CD63, α-SMA, BMP-2, and Runx2, respectively. Differential expression of exosomal miRNAs in normal and HP-induced VSMCs were identified by using whole miRNA microarray technology. GO and KEGG analyses were performed to determine the significant enrichment of functions and signaling pathways in the target genes. In vivo, the CKD-VC rat model was established by administering adenine gavage combined with a high phosphorus diet. The rats were divided into normal control, model, low-dose BSHX, medium-dose BSHX, high-dose BSHX groups, and sevelamer groups. The blood biochemical parameters were measured. Renal histopathology and aortic calcification were observed. Western blot detected the levels of the calcification markers. Quantitative real-time PCR (qPCR) assay detected exosomal microRNA-32 (miR-32) mRNA expression in the aorta, the most differentially expressed exosomal miRNA previously identified. Phosphatase and tensin homolog located on chromosome ten (PTEN)/phosphatidylinositol-3 kinase (PI3K)/protein kinase B (AKT) signaling pathway components were also tested by western blot. Exosomal miRNA-32 and PI3K/AKT signaling pathways were highly differentially expressed between normal and HP-induced VSMCs. In vivo, BSHX improved blood biochemical parameters, renal histopathology, and aortic calcification in CKD-VC rats. BSHX increased the expression level of α-SMA and decreased the level of BMP-2 and Runx2. BSHX also lowered the expression level of exosomal miR-32 mRNA, enhanced PTEN expression, therefore, reduced p-PI3K and p-AKT levels in the aorta. BSHX alleviated VC in CKD rats by downregulating exosomal miR-32 expression in the aorta, thereby promoting PTEN expression and inhibiting the PI3K/AKT signaling pathway.

Osteoprotegerin and Vascular Dysfunction in Patients with Stage 3 Chronic Kidney Disease and Those without Renal Dysfunction: A Case-Control Study.

Osteoprotegerin (OPG) is a marker of vascular calcification and cardiovascular risk in patients with chronic kidney disease (CKD). This study aimed to compare and correlate OPG values with flow-mediated dilation (FMD) and pulse wave velocity (PWV) measurements in patients in stage 3 CKD and those without renal dysfunction. This case-control study was conducted in a specialized hypertension center in 2022. A total of 79 patients over 18 years of age participated in the study. The case group consisted of 30 patients with moderate renal dysfunction (CKD stage 3) and the control group included 49 individuals with glomerular filtration rate ≥ 60 mL/min/1.73 m2. The significance level adopted in the statistical analysis was 5%. Central pulse pressure (cPP), PWV, and augmentation index (AIx) were higher in patients with renal dysfunction. The serum OPG level positively correlated with peripheral and central systolic blood pressure, cPP, PWV, and AIx. Conversely, the serum OPG did not correlate with FMD. OPG and PWV are possible biomarkers of vascular dysfunction that are altered in patients with moderate renal dysfunction. Despite limitations of this study, including that it was a case-control study conducted at a single center, it has the potential, as a proof of concept, to generate the hypothesis of OPG and PWV as biomarkers of early vascular damage in this population.

Oxygenator assisted dynamic microphysiological culture elucidates the impact of hypoxia on valvular interstitial cell calcification

IntroductionMicrophysiological systems (MPS) offer simulation of (patho)physiological parameters. Investigation includes items which lead to fibrosis and calcification in development and progress of calcific aortic valve disease, based e.g. on culturing of isolated valvular interstitial cells (VICs). Hypoxia regulated by hypoxia inducible factors impacts pathological differentiation in aortic valve (AV) disease. This is mimicked via an MPS implemented oxygenator in combination with calcification inducing medium supplementation.MethodsHuman valvular interstitial cells were isolated and dynamically cultured in MPS at hypoxic, normoxic, arterial blood oxygen concentration and cell incubator condition. Expression profile of fibrosis and calcification markers was monitored and calcification was quantified in induction and control media with and without hypoxia and in comparison to statically cultured counterparts.ResultsHypoxic 24-hour culture of human VICs leads to HIF1α nuclear localization and induction of EGLN1, EGLN3 and LDHA mRNA expression but does not directly impact expression of fibrosis and calcification markers. Dependent on medium formulation, induction medium induces monolayer calcification and elevates RUNX2, ACTA2 and FN1 but reduces SOX9 mRNA expression in dynamic and static MPS culture. But combining hypoxic oxygen concentration leads to higher calcification potential of human VICs in calcification and standard medium formulation dynamically cultured for 96 h.ConclusionIn hypoxic oxygen concentration an increased human VIC calcification in 2D VIC culture in an oxygenator assisted MPS was detected. Oxygen regulation therefore can be combined with calcification induction media to monitor additional effects of pathological marker expression. Validation of oxygenator dependent VIC behavior envisions future advancement and transfer to long term aortic valve tissue culture MPS.

The Relationship between Circulating Kidney Injury Molecule-1 and Cardiovascular Morbidity and Mortality in Hemodialysis Patients.

The importance of identifying mortality biomarkers in chronic kidney disease (CKD), and especially in patients treated with hemodialysis (HD), has become evident. In addition to being a marker of tubulointerstitial injury, plasma kidney injury molecule-1 (KIM-1) has been mentioned in regard to HD patients as a risk marker for cardiovascular (CV) mortality and coronary artery calcification. The aim of this study was to assess the level of plasma KIM-1 as a marker of cardiovascular disease (CVD) and mortality in CKD5-HD patients (patients with CKD stage G5D treated with hemodialysis). We conducted a prospective case-control study that included 63 CKD5-HD patients (HD for 1-5 years) followed up for 48 months and a control group consisting of 52 non-dialysis patients diagnosed with CKD stages G1-G5 (ND-CKD). All patients had a CVD baseline assessment including medical history, echocardiography, and electrocardiography (ECG). Circulating plasma KIM-1 levels were determined with single-molecule counting immunoassay technology using an enzyme-linked immunosorbent assay. We obtained the following parameters: serum creatinine and urea; the inflammation markers CRP (C-reactive protein) and IL-6 (interleukin-6); and the anemia markers complete blood count, serum ferritin, and transferrin saturation (TSAT). The mean plasma KIM-1 level was 403.8 ± 546.8 pg/mL, showing a statistically significant correlation with inflammation (CRP, R = 0.28, p = 0.02; IL-6, R = 0.36, p = 0.005) and with anemia (hematocrit, R = -0.5, p = -0.0316; hemoglobin (Hb), R = -0.5, p = 0.02). We found that patients with left ventricular hypertrophy (LVH) on echocardiography (59.7%) had significantly lower mean levels of plasma KIM-1 than patients from the control group (155.51 vs. 432.12 pg/mL; p = 0.026). Regarding the patients' follow-up, we assessed all-cause mortality as an endpoint. After 24 months of follow-up, we found a mortality rate of 22.23%, while after 48 months, the mortality rate was 50.73%. A plasma KIM-1 level < 82.98 pg/mL was significantly associated with decreased survival in hemodialysis patients (p < 0.001). In patients treated with hemodialysis, low levels of plasma KIM-1 were associated with cardiovascular changes and an increased risk of mortality. Plasma KIM-1 levels were significantly higher in HD patients compared to ND-CKD patients.

Predictive markers for aortic atheromatosis and mitral annular calcification in type 2 diabetes patients without established cardiovascular disease

Predictive markers for aortic atheromatosis and mitral annular calcification in type 2 diabetes patients without established cardiovascular disease

Dysregulated lipid metabolism and intervertebral disc degeneration: the important role of ox-LDL/LOX-1 in endplate chondrocyte senescence and calcification

BackgroundLipid metabolism disorders are associated with degeneration of multiple tissues and organs, but the mechanism of crosstalk between lipid metabolism disorder and intervertebral disc degeneration (IDD) has not been fully elucidated. In this study we aim to investigate the regulatory mechanism of abnormal signal of lipid metabolism disorder on intervertebral disc endplate chondrocyte (EPC) senescence and calcification. MethodsHuman intervertebral disc cartilage endplate tissue, cell model and rat hyperlipemia model were performed in this study. Histology and immunohistochemistry were used to human EPC tissue detection. TMT-labelled quantitative proteomics was used to detect differential proteins, and MRI, micro-CT, safranin green staining and immunofluorescence were performed to observe the morphology and degeneration of rat tail intervertebral discs. Flow cytometry, senescence-associated β-galactosidase staining, alizarin red staining, alkaline phosphatase staining, DCFH-DA fluorescent probe, and western blot were performed to detect the expression of EPC cell senescence, senescence-associated secretory phenotype, calcification-related proteins and the activation of cell senescence-related signaling pathways. ResultsOur study found that the highly expressed oxidized low-density lipoprotein (ox-LDL) and Lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1) in human degenerative EPC was associated with hyperlipidemia (HLP). TMT-labelled quantitative proteomics revealed enriched pathways such as cell cycle regulation, endochondral bone morphogenesis and inflammation. The rat model revealed that HLP could induce ox-LDL, LOX-1, senescence and calcification markers high expression in EPC. Moreover, we demonstrated that ox-LDL-induced EPCs senescence and calcification were dependent on the LOX-1 receptor, and the ROS/P38-MAPK/NF-κB signaling pathway was implicated in the regulation of senescence induced by ox-LDL/LOX-1 in cell model.ConclusionsSo our study revealed that ox-LDL/LOX-1-induced EPCs senescence and calcification through ROS/P38-MAPK/NF-κB signaling pathway, providing information on understanding the link between lipid metabolism disorders and IDD.

Tenascin-C is a Promising Marker of High Bone Turnover and Vascular Calcification in Prevalent Hemodialysis Patients

Abstract Background and Aims Tenascin-C (TN-C) is an extracellular matrix glycoprotein associated with high cell turnover and vascular calcification and atherosclerosis. This study determines the frequency of Tenascin-C in uncontrolled parathyroid hormone state and its relation to vascular calcification. Method A cross sectional study included 90 prevalent hemodialysis patients divided into 2 equal groups: uncontrolled iPTH level &amp;gt;300 pg /ml and controlled iPTH (150-300 pg/ml) groups. Serum Tenascin-C was measured by ELISA and vascular calcification was assessed by simple vascular calcification score (adragao score): by Plain X ray on hands, pelvis &amp; vascular access for all patients. Results The prevalence of Tenascin-C and vascular calcification in patient with uncontrolled PTH were 84.4% (38 patients), 46.7% (21 patients) respectively. Tenascin-C was positively correlated with PTH level (r 0.494 p &amp;lt; 0.001) in patients with high bone turnover. Tenascin-C was high in patients with uncontrolled PTH [median (IQR) 637 (4245)u/ml] compared with patients with controlled PTH [median (IQR) 211 (143) u/ml] P value &amp;lt;0.0001. According to Adragao calcification score, in uncontrolled PTH: 31.1% (14 patients) had score 1 and 15.6% (7 patients) score 2. In controlled iPTH all patients had score 0. Patients with vascular calcification had high Tenascin-C median [(IQR) 10697 (53974)] compared with patients without vascular calcification [median (IQR)7697 (18000) u/ml)] P value &amp;lt;0.001. Serum Tenascin-C can predict high bone turnover at cutoff value 7377 ng/ml with AUC 0.794, sensitivity 84.4% and specificity 60 % while predict vascular calcification at cut of value &amp;gt; 8859 ng/ml AUC 0.745, sensitivity 72.7 %, specificity 72.1 %. Patients who have elevated level of tenascin C had 10.3, 3.7 times the risk to have high bone turnover and vascular calcification than negative one respectively. Conclusion Tenascin-C appears to be a sensitive marker for assessment of high bone turnover and vascular calcification in Prevalent Hemodialysis Patients.

Comparative Study Evaluating the Effect of the Administration of Vitamin K1 versus Placebo on Vascular Calcification in Haemodialysis Patients

Abstract Background Cardiovascular calcification is a risk factor and contributor to morbidity and mortality in End stage kidney disease patients. Cardiovascular calcification is most likely due to an imbalance of promoters (e.g. Calcium and phosphate) and inhibitors (e.g. fetuin-A and matrix Gla protein). Aim of the Work We aimed to study the effect of oral vitamin k1 on serum carboxylated Matrix gla protein in patients on maintenance hemodialysis and to study its effect as an important marker of vascular calcification. Patients and Methods This Placebo Controlled clinical trial was conducted for 3 months on 80 adult ESRD patients on regular Hemodialysis randomly allocated into 2 groups of either vitamin K1 versus oral placebo tablet administration for 3 months. Patients in both groups were age and sex matched, study group included 18 (45%) males and 22 (55%) females with mean age ± SD 47.350 ± 14.420 years, while the placebo group included 16 (40%) males and 24 (60%) with mean age ± SD 49.500 ± 14.509 years, with no significant difference between both groups as regard demographic data, access of hemodialysis, and duration of Hemodialysis. Results There was no significant change in bone parameters (serum Ca, PO4 &amp; Ca/PO4 product) after 3 months of vit K1 administration compared to baseline in the study group. Serum phosphorus levels showed a minimal, yet statistically significant decrease after 3 months of placebo administration, this might be attributed to the different doses of PO4 binders in patients of both groups. Consequently, Ca/ PO4 product showed a statistically significant decrease after 3 months of placebo administration (P = 0.002), mostly attributed to the significant decrease in serum phosphorus in the same group over the same period. We observed that serum MGP levels significantly increased after administration of vitamin k1 in study group (P &amp;lt; 0.001) with 78.05% increase. However, a much lower increase, yet statistically significant increase in serum MGP level was noticed in the placebo group (P &amp;lt; 0.001) with 40.60 % increase. There was no statistically significant difference between the two groups according to their risk factors regarding smoking, HTN, HCV, DM, and ISHD. Conclusion We concluded that Oral vitamin K1 therapy significantly increased serum active form of Matrix GLA protein levels among hemodialysis patients with potential decrease in cardiovascular calcification and cardiovascular diseases.

A CEBPB/miR-32–5p/GATA6 axis promotes vascular calcification in type 2 diabetes

Vascular calcification in diabetes patients is a major independent risk factor for developing diabetic cardiovascular complications. However, the mechanisms by which diabetes leads to vascular calcification are complex and not yet fully understood. Our previous study revealed that miR-32–5p is a potential new diagnostic marker for coronary artery calcification. In this study, we found that miR-32–5p levels were significantly greater in the plasma of type 2 diabetes patients with coronary artery calcification and were positively correlated with the coronary artery calcification score. In type 2 diabetic mice, miR-32–5p levels were also elevated in the aorta, and knockout of miR-32–5p inhibited the osteogenic differentiation of vascular smooth muscle cells in vivo. Furthermore, overexpression of miR-32–5p promoted vascular smooth muscle cell calcification, while antagonism of miR-32–5p inhibited vascular smooth muscle cell calcification under high-glucose conditions. GATA binding protein 6 (GATA6) was identified as the key target gene through which miR-32–5p promotes vascular smooth muscle cell calcification. Overexpression of GATA6 antagonized the effects of miR-32–5p on vascular calcification. Additionally, high glucose levels were shown to induce the upregulation of miR-32–5p by activating CCAAT/enhancer binding protein beta (CEBPB). These results suggest that miR-32–5p is an important procalcification factor in vascular calcification associated with type 2 diabetes and identify the CEBPB/miR-32–5p/GATA6 axis as a potential biomarker and therapeutic target for preventing and treating vascular calcification in type 2 diabetes.

Serum Calcification Propensity T50 Is Associated with Soluble Thrombomodulin in Patients on Hemodialysis.

Background/Objectives: Levels of circulating soluble thrombomodulin (sTM), an anticoagulant factor, are associated with the severity and progression of arteriosclerotic diseases. However, the role of elevated sTM levels remains to be clarified in patients on dialysis. As the calcification propensity time T50 is a novel marker of arterial calcification, we aimed to determine the association between sTM and T50 in patients on hemodialysis (HD). Methods: This cross-sectional study included 49 adult patients on maintenance HD. Correlation analysis was performed to test the association between T50 and patient characteristics. Linear regression was used to evaluate the association between T50 and sTM. Results: Partial correlation analysis showed a strong association between T50 and glycated albumin, phosphorous, and sTM levels (partial correlation coefficient: r [partial] = -0.359, p = 0.023; r [partial] = -0.579, p < 0.001; and r [partial] = 0.346, p = 0.029, respectively). Multivariate linear regression analysis revealed that only sTM level was significantly and positively associated with T50 (β = 0.288; t = 2.27; p = 0.029; 95% confidence interval, 0.082-1.403). Conclusions: sTM is independently and positively associated with the propensity time for calcification, suggesting that sTM could be a good marker of arterial calcification progression in patients on HD.

#1943 The association of uncarboxylated, non-phosphorylated Matrix Gla protein with arterial stiffness in hemodialysis and peritoneal dialysis patients

Abstract Background and Aims Vitamin K deficiency has been identified as a marker of vascular calcification AND STIFNESS and an independent cardiovascular risk factor in hemodialysis (HD) and peritoneal dialysis (PD) patients, as the most powerful inhibitor of vascular calcification, Matrix Gla Protein requires vitamin K to become activated. However, until to date, it has not yet been clarified whether hepatic or extrahepatic markers of vitamin K status reflect the arterial status of dialysis patients. In this study we aimed to investigate the association of vitamin K deficiency with arterial stiffness in End-Stage Kidney Disease (ESKD) patients. Method In 42 ESKD patients undergoing either HD or PD, we measured plasma levels of the inactive vitamin-K dependent Matrix Gla Protein (dp-ucMGP) and serum levels of prothrombin (PIVKA-II) as markers of extrahepatic and hepatic insufficiency of vitamin K (CARIM Institute, Maastricht, Netherlands). In these patients we determined arterial stiffness parameters (pulse wave velocity-PWV) by the Mobil-O-Graph device (IEM, Stolberg, Germany). Results Serum PIVKA-II was associated with T2D duration (r = −0.38, p = 0.013), phosphorus levels (r = −0.41, p = 0.009) serum albumin (r = −0.33, p = 0.036) Spearman's rho test, and the type of transporter in PD patients (p = 0.039), Kruskal-Wallis test. Plasma dp-ucMGP was associated with PWV (r = 0.51, p = 0.001), peripheral (r = −0.37, p = 0.016) and central diastolic blood pressure (BP) (r = −0.34, p = 0.026) and age (r = 0.41, p = 0.007), Spearman's rho. Patients with T2DM, history of acute myocardial infarction and those receiving warfarin had significantly increased levels of circulating dp-ucMGP (p = 0.036, p = 0.039 and p &amp;lt; 0.0001, respectively, Kruskal-Wallis). Warfarin was associated with a 2.5-fold and a 23-fold increase in dp-ucMGP and PIVKA-II levels, respectively. Stepwise multiple regression analysis showed that PWV (p = 0.001, B = 494, 95% CI: 242-746) was an independent predictor of dp-ucMGP, independent of age, T2T2, history of myocardial infraction and diastolic BP. Conclusion Elevated plasma dp-ucMGP levels (suggesting extrahepatic vitamin K deficiency) were associated with increased arterial stiffness in dialysis patients.

Vertebral Endplate Defects Induced Mechanical Alterations and Disc Calcification.

Cross sectional comparative study. The current study aims to explore the calcification potential (BMP2 expression) of intervertebral discs and its association with the presence of vertebral endplate defects visible on MRI. Forty-seven herniated lumbar disc samples obtained from patients aged 20-76 (31M/16F) undergoing surgery. Five-µm thin sections were stained with H&E in order to assign a histological degeneration score (HDS) from 0-15 on the basis of cell density (0-5), structural alterations (0-4), granular changes (0-3) and mucus degeneration (0-3). Sections were immuno-stained with anti BMP-2 antibodies to observe the calcification potential in these discs. In addition, pre-operativeT2-T1 W MRI images of the lumbar spine were analyzed for the presence and type (typical or atypical) of vertebral endplate defects, grade of disc degeneration (Pfirrmann grade I-V), presence of high intensity zones (HIZ), and Modic changes at the operated level. Vertebral endplate defects, Modic changes & HIZ were observed in 81%, 29% and 21% of patients respectively. Mean HDS & BMP-2 expression was 9 ± 2 and mean 71 ± 36spots/mm2 respectively. Discs with adjacent vertebral endplate defects showed increased cell density (P = .004), mucus degeneration (P = .002), HDS (P = .01) and BMP-2 expression (P = .01). Discs with HIZ also had increased HDS, but significance was seen with increased BMP2 expression (P = .006). HDS showed a positive correlation with BMP 2 expression (r = .30, P = .04). These findings suggest that the altered mechanical environment of discs is strongly associated with BMP-2 expression which is an important marker of intervertebral disc calcification.