Vascular Calcification In Chronic Kidney Disease Research Articles

Vascular calcification is associated with Wnt-signaling pathway and blood pressure variability in chronic kidney disease rats.

Vascular calcification (VC) is a common complication in chronic kidney disease (CKD) and has been shown to be associated with increased cardiovascular events and mortality. This study was to explore the role of Wnt-signaling pathway in CKD VC, and the association between VC and blood pressure variability (BPV) which is a risk factor of cardiovascular events. Adult male Sprague-Dawley rats were divided into adenine-induced CKD group (n = 5), 5/6 nephrectomy CKD group (n = 5), sham group (n = 5) and control group (n = 5). Low-calcium-high-phosphate diets were introduced to induce vascular calcification. Both daytime (hour-to-hour during the day) and mid-term (day-to-day for 9 days) blood pressure (BP) were collected and analyzed for BPV metrics. At sacrifice, kidney, heart and aorta samples were taken for histological analyses. Calcium deposition in aorta was identified with Alizarin Red stain and graded. Immunohistochemistry stain and western blot were performed for Wnt3a, Wnt5a, β-catenin, sclerostin, osteopontin, and α-SMA. Compared with control rats, CKD rats suffered from markedly severer VC (Grade 2.6 ± 0.2 and 1.8 ± 0.8 vs 0.0 ± 0.0 and 0.2 ± 0.4, P = .0010). VC was positively correlated with vascular Wnt3a and β-catenin expression (P = .0032 and .0000), but not significantly associated with Wnta5a or sclerostin. Besides, CKD rats showed increased BPV (P < .001), which was also positively correlated with VC. We confirmed that CKD rats had enhanced Wnt-signaling in vascular tissue and severer aorta calcification together with increased BPV. Wnt pathway may be a potential target in future VC and BPV management in CKD.

Erythropoietin attenuates vascular calcification by inhibiting endoplasmic reticulum stress in rats with chronic kidney disease

Previous studies suggested that endoplasmic reticulum (ER) stress induced-apoptosis promoted vascular calcification (VC). Interestingly, erythropoietin (EPO), an endogenous glycoprotein, exerts multiple tissue protective effects by inhibiting ER stress and apoptosis. We investigated the role and potential mechanism of EPO on VC in chronic kidney disease (CKD) rats and cultured vascular smooth muscle cells (VSMCs). The calcification model was established by subtotal nephrectomy in vivo or phosphate overload in vitro. The protein level of EPO receptor (EPOR) was increased in the calcified aortas of CKD rats. EPO prevented the reduction of VSMC phenotypic markers, and reversed the increased calcium content and calcium salt deposition in the aortas of CKD rats and cultured calcified VSMCs. The protein levels of activating transcription factor 4 (ATF4) and glucose-regulated protein 94 (GRP94) were upregulated in aortas and VSMCs under calcifying conditions, indicating ER stress activation. EPO treatment of CKD rats or calcified VSMCs downregulated the protein levels of ATF4 and GRP94. Furthermore, ER stress-mediated apoptosis, determined by the protein levels of CCAAT⁄enhancer-binding protein-homologous protein and cleaved caspase 12, was increased in tunicamycin or calcification media-treated VSMCs, but the increased effect was reversed in EPO-treated groups. The increased apoptotic cells in calcified VSMCs, as indicated by Hoechst staining and flow cytometry, were downregulated by the co-administration of EPO or 4-phenyl butyric acid. In conclusion, EPO might attenuate VC by inhibiting ER stress mediated apoptosis through EPOR signaling.

The Role of Vitamin K in Vascular Calcification.

Vascular calcification (VC) is common in advanced chronic kidney disease (CKD), contributes to cardiovascular disease (CVD), and associates with increased mortality. Major risk factors for VC in CKD are increasing age, dialysis vintage, and positive net calcium-phosphate balance. To date, no specific therapy that prevents progression or facilitates regression of VC beyond careful attention to calcium and phosphate balance exists. Accumulating evidence demonstrates that CKD patients may incur subclinical vitamin K deficiency. This deficiency may be induced by exhaustion of vitamin K due to its high requirement by vitamin K-dependent proteins to inhibit VC. This review analyzes the pathophysiological mechanisms and clinical consequences of vitamin K deficiency with emphasis on its involvement on vascular calcification in CKD and end-stage renal disease and its relationship to the bone-vascular axis.

Pathogenesis and management of vascular calcification in CKD and dialysis patients.

Patients with chronic kidney disease (CKD) have a predisposition to develop vascular calcification due to dysregulated homeostatic mechanisms, which lead to an imbalance in the circulatory promoters and inhibitors of vascular calcification, leading to a net calcification stress. These factors promote ectopic calcification and induce vascular smooth muscle cells to undergo osteogenic differentiation and actively calcify the vascular media. The article summarizes clinically relevant pathogenic mechanisms of vascular calcification in patients with CKD and in dialysis patients and summarizes novel therapeutic interventions. In addition to the management of traditional cardiovascular risk factors, patients with CKD-mineral and bone disorder need close attention in the management of the mineral metabolism to prevent adverse effects on the bone and vascular compartments. This article reviews current evidence and therapeutic guidelines in the management of mineral metabolism in CKD and dialysis.

Wnt1 inhibits vascular smooth muscle cell calcification by promoting ANKH expression

AimsWnt signaling plays a critical role in vascular calcification (VC). Wnt factors induce different physiological and pathological effects on cardiovascular functions. Wnt1, a ligand of Wnt/β-catenin signaling, promotes pro-angiogenesis and reduces myocardial infarction. The role of Wnt1 on VC in chronic kidney disease (CKD) is not fully understood. Methods and resultsWe used human vascular smooth muscle cells (VSMCs) and a rat model of chronic renal failure (CRF), and observed a native protective mechanism by which VC is reduced via the activation of Wnt1 and its transcriptional target ANKH inorganic pyrophosphate transport regulator (ANKH) gene. ANKH is an essential calcification inhibitor that effluxes inorganic pyrophosphate (PPi) from VSMCs to play an inhibitory role in VC. Vascular ANKH and plasma PPi were significantly downregulated in the rat model of CRF. The knockdown or inhibition of ANKH reversed the effect of Wnt1 on VC in VSMCs. Clinical analysis revealed low plasma levels of Wnt1 and PPi were associated with CKD in patients. Applying a Wnt/β-catenin signaling agonist can alleviate the progression of VC. ConclusionThis work reveals the ANKH regulation of Wnt1 in VSMCs is essential for blocking VC. Our findings may contribute to the development of medications that target Wnt signaling and/or ANKH to inhibit VC.

Chemerin inhibits vascular calcification through ChemR23 and is associated with lower coronary calcium in chronic kidney disease.

BackgroundChemerin is an adipokine that signals through the G protein‐coupled receptor ChemR23 and is associated with inflammation, glucose homeostasis, lipid metabolism and renal function, all of which strongly influence cardiovascular risk. However, elevated chemerin provides a survival advantage in patients with chronic kidney disease (CKD), but how this relates to the cardiovascular phenotype is unknown.ObjectivesThe aim of the present study was to establish the association of chemerin with coronary calcification and to determine the effects of chemerin signalling, through ChemR23, in vascular smooth muscle cell (VSMC) calcification.MethodsPlasma chemerin was measured in 113 patients with CKD and 50 healthy controls. All patients underwent computed tomography to determine coronary artery calcium (CAC) score. VSMCs were isolated from wild‐type and ChemR23 knock‐out mice and treated with chemerin.ResultsMultivariate analyses established creatinine, cholesterol, body mass index and tumour necrosis factor as significant confounders for circulating chemerin levels. Despite these positive associations with renal function, cardiometabolic risk factors and inflammation, chemerin was inversely associated with CAC both in an age‐ and sex‐adjusted analysis and in a multivariate analysis adjusting for the aforementioned confounders. In addition, circulating chemerin levels were associated with the calcification inhibitors matrix gla protein (MGP) and fetuin‐A. Finally, chemerin significantly reduced phosphate‐induced calcification and increased MGP expression in VSMCs, whereas chemerin was devoid of these effects in VSMCs lacking ChemR23.ConclusionIn conclusion, these results suggest that chemerin signalling through ChemR23 in VSMCs protects against vascular calcification in CKD.

Magnesium and calciprotein particles in vascular calcification: the good cop and the bad cop.

Vascular calcification is a major contributor to increased cardiovascular mortality in chronic kidney disease (CKD). Recently, calciprotein particles (CPP) were identified to drive the calcification process. CPP may explain the effects of high phosphate on vascular calcification. Magnesium is a promising novel therapeutic approach to halt vascular calcification, because it inhibits CPP maturation and is associated with reduced cardiovascular mortality in CKD. We aim to examine the current evidence for the role of CPP in the calcification process and to explain how magnesium prevents calcification. A recent meta-analysis concluded that reducing high phosphate levels in CKD patients does not associate with lowering cardiovascular mortality. Inhibition of CPP formation prevents phosphate-induced calcification in vitro. Consequently, delaying CPP formation and maturation may be a clinical approach to reduce calcification. Magnesium inhibits CPP maturation and vascular calcification. Clinical pilot studies suggest that magnesium is a promising intervention strategy against calcification in CKD patients. CPP induce vascular calcification and are modulated by serum phosphate and magnesium concentrations. Magnesium is a strong inhibitor of CPP maturation and therefore, a promising therapeutic approach to reduce vascular calcification in CKD. Currently, several studies are being performed to determine the clinical outcomes of magnesium supplementation in CKD.

SAT-266 EVALUATION OF AORTIC CALCIFICATION VOLUME AND SITES USING A NEWLY DEVELOPED THREE-DIMENSIONAL VISUALIZATION AND QUANTIFICATION METHOD IN CHRONIC KIDNEY DISEASE PATIENTS WITH AND WITHOUT DIABETES

Chronic kidney disease (CKD) and diabetes mellitus (DM) are both crucial risk factors for vascular calcification, CVD and mortality. There are a great number of studies regarding the severity of vascular calcification in CKD and DM. While Agatston scoring is often used evaluating coronary artery calcification, there are very few studies to evaluate both severity and site of aortic calcification. The purpose of our study was to examine the volume and site of aortic calcification in CKD patients with and without DM using a newly developed three-dimensional visualization and quantification method. Fifty patients who were hospitalized and started hemodialysis at our hospital were included in the present study. They were divided into the two groups depending on the presence of DM; those with CKD and without DM group (CKD group, n=31), those with CKD and DM group (CKD+DM group, n=19). The volume and site of aortic calcification were assessed by CT-scan using a three-dimensional visualization and quantification method according to a previous study (Figure). We compared the calcification volume in total aorta and each of the five sites between the two groups. Total calcification volume was significantly greater in the CKD+DM group than in the CKD group. As for calcification sites, calcification volume in the thoracic aorta and abdominal aorta was greater in CKD+DM group compared to the CKD group. There were no significant differences in calcification volume in the aortic root, ascending aorta, and aortic arch. Total calcification volume of the aorta, calcification volume of the thoracic aorta, and calcification volume of the abdominal aorta were each significantly correlated with age, diastolic blood pressure and pulse pressure. Using a newly developed three-dimensional visualization and quantification method, the present study demonstrated that aortic calcification was more severe in CKD patients with DM than in those without DM and that calcification seemed to be likely to occur especially in the abdominal aorta. To clarify the mechanisms, a future detailed study is needed.

An overview of the mechanisms in vascular calcification during chronic kidney disease.

Chronic kidney disease (CKD) facilitates a unique environment to strongly accelerate vascular calcification - the pathological deposition of calcium-phosphate in the vasculature. These calcifications are associated with the excessive cardiovascular mortality of CKD patients. Vascular calcification is a multifaceted active process, mediated, at least partly, by vascular smooth muscle cells. These cells are able to transdifferentiate into cells with osteo/chondrogenic properties, which exert multiple effects to facilitate vascular tissue mineralization. As the understanding of the underlying pathophysiology increases, first therapeutic concepts begin to emerge. This brief review provides an overview on the so far known mechanisms involved in the initiation and progression of vascular calcification in CKD.

The Key Role of Phosphate on Vascular Calcification.

Vascular calcification (VC) is common in dialysis and non-dialysis chronic kidney disease (CKD) patients, even in the early stage of the disease. For this reason, it can be considered a CKD hallmark. VC contributes to cardiovascular disease (CVD) and increased mortality among CKD patients, although it has not been proven. There are more than one type of VC and every form represents a marker of systemic vascular disease and is associated with a higher prevalence of CVD in CKD patients, as shown by several clinical studies. Major risk factors for VC in CKD include: Increasing age, dialysis vintage, hyperphosphatemia (particularly in the setting of intermittent or persistent hypercalcemia), and a positive net calcium and phosphate balance. Excessive oral calcium intake, including calcium-containing phosphate binders, increases the risk for VC. Moreover, it has been demonstrated that there is less VC progression with non-calcium-containing phosphate binders. Unfortunately, until now, a specific therapy to prevent progression or to facilitate regression of VC has been found, beyond careful attention to calcium and phosphate balance.

Receptor for advanced glycation end products: a key molecule in the genesis of chronic kidney disease vascular calcification and a potential modulator of sodium phosphate co-transporter PIT-1 expression.

Chronic kidney disease (CKD) is associated with increased cardiovascular mortality, frequent vascular calcification (VC) and accumulation of uraemic toxins. Advanced glycation end products and S100 proteins interact with the receptor for advanced glycation end products (RAGE). In the present work, we aimed to investigate the role(s) of RAGE in the CKD-VC process. Apoe-/- or Apoe-/-Ager (RAGE)-/- male mice were assigned to CKD or sham-operated groups. A high-phosphate diet was given to a subgroup of Apoe-/-and Apoe-/-Ager-/- CKD mice. Primary cultures of Ager+/+ and Ager-/- vascular smooth muscle cells (VSMCs) were established and stimulated with either vehicle, inorganic phosphate (Pi) or RAGE ligands (S100A12; 20 µM). After 12 weeks of CKD we observed a significant increase in RAGE ligand (AGE and S100 proteins) concentrations in the serum of CKD Apoe-/- mice. Ager messenger RNA (mRNA) levels were 4-fold higher in CKD vessels of Apoe-/- mice. CKD Apoe-/- but not CKD Apoe-/- or Ager-/- mice displayed a marked increase in the VC surface area. Similar trends were found in the high-phosphate diet condition. mRNA levels of Runx2 significantly increased in the Apoe-/- CKD group. In vitro, stimulation of Ager+/+VSMCs with Pi or S100A12 induced mineralization and osteoblast transformation, and this was inhibited by phosphonoformic acid (Pi co-transporters inhibitor) and Ager deletion. In vivo and in vitro RAGE was necessary for regulation of the expression of Pit-1, at least in part through production of reactive oxygen species. RAGE, through the modulation of Pit-1 expression, is a key molecule in the genesis of VC.

Amelioration of Uremic Toxin Indoxyl Sulfate-Induced Osteoblastic Calcification by SET Domain Containing Lysine Methyltransferase 7/9 Protein

Background: Vascular calcification (VC) is a very common phenomenon in patients with chronic kidney disease (CKD). It has been reported that some histone methylation play a role in VC as an epigenetic regulator. Indoxyl sulfate (IS) is a protein-bound uremic toxin that has been proven as one of the major risk factors of cardiovascular disease in CKD. SET domain containing lysine methyltransferase 7/9 (SET7/9) is one of the important histone methyltransferases. Objectives: This study aimed to determine the effect of IS on the expression of SET7/9 and the role of SET7/9 in IS-induced osteoblastic differentiation and calcification of vascular smooth muscle cells (VSMCs). Methods: VSMCs were incubated with various concentrations of IS for different durations to assess osteoblastic differentiation and expression of SET7/9. Western blot analysis and quantitative real-time polymerase chain reaction were performed to assess the protein and mRNA levels of SET7/9 respectively. The calcium content was measured to evaluate calcification. Results: Osteoblastic differentiation and calcification of VSMCs and downregulation of the expression of SET7/9 were observed after IS treatment. The autophagy was activated after treatment with IS, whereas the inhibition of the autophagy partially attenuated the effect of IS on both the stimulation of the expression of runt-related transcription factor 2 and calcium deposition. Conclusions: Our data demonstrated that SET7/9 downregulation and autophagy activation may be the key mechanism of IS-induced VC in CKD.

SGK1 induces vascular smooth muscle cell calcification through NF-κB signaling.

Medial vascular calcification, associated with enhanced mortality in chronic kidney disease (CKD), is fostered by osteo-/chondrogenic transdifferentiation of vascular smooth muscle cells (VSMCs). Here, we describe that serum- and glucocorticoid-inducible kinase 1 (SGK1) was upregulated in VSMCs under calcifying conditions. In primary human aortic VSMCs, overexpression of constitutively active SGK1S422D, but not inactive SGK1K127N, upregulated osteo-/chondrogenic marker expression and activity, effects pointing to increased osteo-/chondrogenic transdifferentiation. SGK1S422D induced nuclear translocation and increased transcriptional activity of NF-κB. Silencing or pharmacological inhibition of IKK abrogated the osteoinductive effects of SGK1S422D. Genetic deficiency, silencing, and pharmacological inhibition of SGK1 dissipated phosphate-induced calcification and osteo-/chondrogenic transdifferentiation of VSMCs. Aortic calcification, stiffness, and osteo-/chondrogenic transdifferentiation in mice following cholecalciferol overload were strongly reduced by genetic knockout or pharmacological inhibition of Sgk1 by EMD638683. Similarly, Sgk1 deficiency blunted vascular calcification in apolipoprotein E-deficient mice after subtotal nephrectomy. Treatment of human aortic smooth muscle cells with serum from uremic patients induced osteo-/chondrogenic transdifferentiation, effects ameliorated by EMD638683. These observations identified SGK1 as a key regulator of vascular calcification. SGK1 promoted vascular calcification, at least partly, via NF-κB activation. Inhibition of SGK1 may, thus, reduce the burden of vascular calcification in CKD.

TDAG51 is a key modulator of vascular calcification and osteogenic transdifferentiation of arterial smooth muscle cells

Cardiovascular disease (CVD) is the primary cause of morbidity and mortality in patients with chronic kidney disease (CKD). More than half of all deaths from patients with end-stage renal disease (ESRD) requiring dialysis can be attributed to CVD. Although traditional risk factors for CVD are prevalent in ESRD, they cannot fully explain the high mortality rates. Vascular calcification (VC) in the medial layer of the vessel wall is a unique and prominent feature in patients with advanced CKD and is now recognized as an important predictor and an independent risk factor for cardiovascular and all-cause and mortality in these patients. VC in CKD is triggered by vascular smooth muscle cells (VSMCs) transforming into osteoblasts, a consequence of elevated circulating phosphate levels due to poor kidney function. Understanding and targeting this SMC trans-differentiation and subsequent VC represents a viable therapeutic avenue for managing CKD complications. Similar to bone formation, VC is a highly regulated process that draws many parallels with osteogenic differentiation. We have recently observed that T-cell Death Associated Gene 51 (TDAG51), a protein upregulated by oxidative and endoplasmic reticulum stress, is induced in SMCs under conditions of hyperphosphatemia and is expressed in the medial layer of calcified human vessels. We have found that ablation of TDAG51 reduces SMC trans-differentiation and VC, both in human SMCs treated with TDAG51 siRNA and in mouse VSMCs isolated from TDAG51−/− aortas. To explain these findings, we observed that TDAG−/− VSMCs express reduced levels of the of the Pit-1, a solute transporter responsible for cellular phosphate uptake. Consistent with this observation, reduced Pit-1 expression was associated with reduced intracellular phosphate levels and reduced phosphate-induced apoptosis. Further, TDAG−/− VSMCs exhibit significantly reduced transcriptional activity of a phosphate-inducible transcription factor, and well-established driver of VC, known as Runx2. Support or Funding Information This work was supported in part by research grants to Richard C. Austin from the Heart and Stroke Foundation of Ontario (T-6146), the Heart and Stroke Foundation of Canada (G-13-0003064 and G-15-0009389) and the Canadian Institutes of Health Research (74477). TDAG51 is involved in the development and progression of VC through the regulation of intracellular phosphate content and Runx2 transcriptional activity. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Defective interplay between mTORC1 activity and endoplasmic reticulum stress-unfolded protein response in uremic vascular calcification.

Vascular calcification increases the risk of cardiovascular disease and death in patients with chronic kidney disease (CKD). Increased activity of mammalian target of rapamycin complex 1 (mTORC1) and endoplasmic reticulum (ER) stress-unfolded protein response (UPR) are independently reported to partake in the pathogenesis of vascular calcification in CKD. However, the association between mTORC1 activity and ER stress-UPR remains unknown. We report here that components of the uremic state [activation of the receptor for advanced glycation end products (RAGE) and hyperphosphatemia] potentiate vascular smooth muscle cell (VSMC) calcification by inducing persistent and exaggerated activity of mTORC1. This gives rise to prolonged and excessive ER stress-UPR as well as attenuated levels of sestrin 1 ( Sesn1) and Sesn3 feeding back to inhibit mTORC1 activity. Activating transcription factor 4 arising from the UPR mediates cell death via expression of CCAAT/enhancer-binding protein (c/EBP) homologous protein (CHOP), impairs the generation of pyrophosphate, a potent inhibitor of mineralization, and potentiates VSMC transdifferentiation to the osteochondrocytic phenotype. Short-term treatment of CKD mice with rapamycin, an inhibitor of mTORC1, or tauroursodeoxycholic acid, a bile acid that restores ER homeostasis, normalized mTORC1 activity, molecular markers of UPR, and calcium content of aortas. Collectively, these data highlight that increased and/or protracted mTORC1 activity arising from the uremic state leads to dysregulated ER stress-UPR and VSMC calcification. Manipulation of the mTORC1-ER stress-UPR pathway opens up new therapeutic strategies for the prevention and treatment of vascular calcification in CKD.

Effect of vitamin D supplementation on serum sclerostin levels in chronic kidney disease

Vitamin D deficiency, cardiovascular disease and abnormal bone mineral metabolism are common in chronic kidney disease (CKD). Abnormal bone mineral metabolism has been linked to vascular calcification in CKD. Sclerostin has emerged as an important messenger in cross talk between bone-vascular axis. We analyzed sclerostin in subjects who participated in the randomized, double blind, placebo controlled trial investigating the effect of cholecalciferol supplementation on vascular function in non­diabetic CKD stage G3-4 and vitamin D ≤ 20 ng/ml [CTRI/2013/05/003648]. Patients were randomized (1:1) to receive either two directly observed oral doses of 300,000 IU of cholecalciferol or matching placebo at baseline and 8 weeks. Of the 120 subjects enrolled, 58 in the cholecalciferol group and 59 in the placebo group completed the study. At baseline, serum levels of sclerostin were similar in both groups (cholecalciferol - median;190pg/ml, IQR;140–260 pg/ml and placebo - median;180 pg/ml, IQR; 140–240 pg/ml, p = 0.67). 16 weeks after cholecalciferol supplementation, there was no change in level of sclerostin (mean change;1.10 pg/ml, 95%CI; −27.34 to 29.34 pg/ml, p = 0.25). However, a significant decrease in sclerostin level was noted in the placebo group (mean change; −31.94 pg/ml, 95%CI; −54.76 to −9.13 pg/ml, p = 0.002). Change (Δ) in sclerostin level at 16 weeks correlated negatively with Δ eGFR (r = −0.20, p = 0.03) and positively with Δuric acid (r = 0.37, p < 0.001) but not with Δ25(OH) D (r = 0.06, p = 0.54), Δ iPTH (r = − 0.03, p = 0.78) ΔFGF23 (r = − 0.08, p = 0.38) and Δ125 (OH)2 D (r = − 0.04, p = 0.65). In conclusion, high dose cholecalciferol supplementation did not change sclerostin levels in non-diabetic stage 3–4 CKD subjects.

Fibroblast growth factor-23 and vascular calcification in chronic kidney disease and hemodialysis patients

Context Fibroblast growth factor-23 (FGF-23) is secreted by osteoblasts and regulates phosphate and vitamin D homeostasis. As a potential explanatory mechanism of FGF-23-associated mortality, multiple studies have consistently demonstrated that higher FGF-23 levels are independently associated with greater risk of prevalent and incident left ventricular hypertrophy (LVH). In contrast, observational studies reported conflicting results on the association of FGF-23 with arterial calcification, which is another prominent pattern of cardiovascular injury in chronic kidney disease (CKD). Aims The aim was to correlate between serum FGF-23 and vascular calcification (VC) in CKD and hemodialysis (HD) patients. Settings and design A single-center cross-sectional study was conducted on 60 patients who were divided into two groups. Group I included thirty patients with CKD stages 4 and 5, and group II included thirty patients on maintenance HD. Group III included 30 age-matched and sex-matched healthy volunteers. Materials and methods Estimation of serum calcium, phosphorus, bone-specific alkaline phosphatase, intact parathyroid hormone, and serum FGF-23 level was carried out. Assessment of LVH by echocardiography and VC by multidetector computed tomography was done. Results There was a statistically significant negative correlation between FGF-23 and serum calcium level in group I and of no statistical significant correlation in group II and III, whereas there were a statistically significant positive correlations between FGF-23 with serum phosphorus, bone-specific alkaline phosphatase and intact parathyroid hormone in groups I and II and of no statistical significant correlations in group III. There were statistically significant positive correlations between FGF-23 and both left ventricular mass index and VC in groups I and II (P Conclusion FGF-23 correlates with LVH and VC in CKD and HD patients.

Bone Morphogenetic Proteins 2/4 Are Upregulated during the Early Development of Vascular Calcification in Chronic Kidney Disease.

Vascular calcification is a main cause of increased cardiovascular morbidity and mortality in chronic kidney disease (CKD) patients. This study aimed to investigate the role of the bone morphogenetic protein (BMP) signaling pathway in the early development of vascular calcification in CKD. A CKD vascular calcification rat model was established by providing rats with a 1.8% high-phosphorus diet and an intragastric administration of 2.5% adenine suspension. The kidney and aortic pathologies were analyzed. Blood biochemical indicators, serum BMP-2 and BMP-4 levels, and aortic calcium content were determined. The expression levels of BMP-2, BMP-4, bone morphogenetic protein receptor-IA (BMPR-IA), and matrix Gla protein (MGP) in aorta were examined by quantitative real-time polymerase chain reaction and immunohistochemistry. Compared with the normal control (Nor) rats, the CKD rats exhibited a significantly decreased body weight and an increased kidney weight as well as abnormal renal function and calcium-phosphorus metabolism. Aortic von Kossa and Alizarin red staining showed massive granular deposition and formation of calcified nodules in aorta at 8 weeks. The aortic calcium content was significantly increased, which was positively correlated with the serum BMP-2 (r = 0.929; P < 0.01) and serum BMP-4 (r = 0.702; P < 0.01) levels in CKD rats. The rat aortic BMP-2 mRNA level in the CKD rats was persistently increased, and the BMP-4 mRNA level was prominently increased at the 4th week, declining thereafter. Strong staining of BMP-2, BMP-4, BMPR-IA, and MGP proteins was observed in the tunica media of the aorta from the 4th week after model induction. In conclusion, activation of the BMP signaling pathway is involved in the early development of vascular calcification in CKD. Therefore, elevated serum BMP-2 and BMP-4 levels may serve as serum markers for CKD vascular calcification.

Pathophysiology and treatment of cardiovascular disease in pediatric chronic kidney disease.

Life expectancy in patients with all stages of chronic kidney disease (CKD) falls far short of that in the general population. Cardiovascular disease is the leading cause of mortality in pediatric patients with CKD. In contrast to the intimal atherosclerotic lesions that characterize cardiovascular disease in the general population, vascular endothelial dysfunction, medial arterial calcification, and cardiac dysfunction contribute to cardiovascular pathological conditions in CKD. The pathogenesis of these lesions, the origins of which can be identified in the absence of traditional cardiovascular risk factors, is incompletely understood. CKD-mediated vascular calcification in CKD is characterized by a transition of vascular smooth muscle cells to an osteoblast-like phenotype and altered bone and mineral metabolism are strongly linked to progressive cardiovascular disease in this population. Renal osteodystrophy therapies, including phosphate binders, vitamin D analogs, and calcimimetics, have an impact on the progression of cardiovascular disease. However, cardiovascular disease has its origins before the development of secondary hyperparathyroidism, and optimal therapeutic regimens that minimize cardiac dysfunction, vascular calcification, and early mortality remain to be defined.

Deoxycholic Acid, a Metabolite of Circulating Bile Acids, and Coronary Artery Vascular Calcification in CKD

Vascular calcification is common among patients with chronic kidney disease (CKD),and it is associated with all-cause and cardiovascular disease mortality. Deoxycholic acid, a metabolite of circulating bile acids, is elevated in CKD and induces vascular mineralization and osteogenic differentiation in animal models. Cohort analysis of clinical trial participants. 112 patients with moderate to severe CKD (estimated glomerular filtration rate, 20-45mL/min/1.73m2) who participated in a randomized controlled study to examine the effects of phosphate binders on vascular calcification. Serum deoxycholic acid concentration. Baseline coronary artery calcification (CAC) volume score and bone mineral density (BMD) and change in CAC volume score and BMD after 9 months. Deoxycholic acid was assayed in stored baseline serum samples using liquid chromatography-tandem mass spectrometry, CAC was measured using a GE-Imitron C150 scanner, and BMD was determined using computed tomographic scans of the abdomen with calibrated phantom of known density. Higher serum deoxycholic acid concentrations were significantly correlated with greater baseline CAC volume and lower baseline BMD. After adjusting for demographics, coexisting illness, body mass index, estimated glomerular filtration rate, and concentrations of circulating markers of mineral metabolism, including serum calcium, phosphorus, vitamin D, parathyroid hormone, and fibroblast growth factor 23, a serum deoxycholic acid concentration > 58ng/mL (the median) was positively associated with baseline CAC volume (β=0.71; 95% CI, 0.26-1.16; P=0.003) and negatively associated with baseline BMD (β=-20.3; 95% CI,-1.5 to-39.1; P=0.04). Serum deoxycholic acid concentration > 58ng/mL was not significantly associated with change in CAC volume score after 9 months (β=0.06; 95% CI,-0.09 to 0.21; P=0.4). The analysis for the relationship between baseline deoxycholic acid concentrations and change in BMD after 9 months was not statistically significant, but was underpowered. The use of nonfasting serum samples is a limitation because deoxycholic acid concentrations may vary based on time of day and dietary intake. Few trial participants with complete data to evaluate the change in CAC volume score (n=75) and BMD (n=59). No data for changes in deoxycholic acid concentrations over time. Among patients with moderate to severe CKD, higher serum deoxycholic acid concentrations were independently associated with greater baseline CAC volume score and lower baseline BMD.