Browsing by Subject "Vascular calcification"

Now showing 1 - 5 of 5
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    A comparison of calcium to zoledronic acid for improvement of cortical bone in an animal model of CKD
    (Wiley, 2014-04) Moe, Sharon M.; Chen, Neal X.; Newman, Christopher L.; Gattone II, Vincent H.; Organ, Jason M.; Chen, Xianming; Allen, Matthew R.; Department of Medicine, IU School of Medicine
    Patients with chronic kidney disease (CKD) have increased risk of fractures, yet the optimal treatment is unknown. In secondary analyses of large randomized trials, bisphosphonates have been shown to improve bone mineral density and reduce fractures. However, bisphosphonates are currently not recommended in patients with advanced kidney disease due to concern about oversuppressing bone remodeling, which may increase the risk of developing arterial calcification. In the present study we used a naturally occurring rat model of CKD with secondary hyperparathyroidism, the Cy/+ rat, and compared the efficacy of treatment with zoledronic acid, calcium given in water to simulate a phosphate binder, and the combination of calcium and zoledronic acid. Animals were treated beginning at 25 weeks of age (approximately 30% of normal renal function) and followed for 10 weeks. The results demonstrate that both zoledronic acid and calcium improved bone volume by micro-computed tomography (µCT) and both equally suppressed the mineral apposition rate, bone formation rate, and mineralizing surface of trabecular bone. In contrast, only calcium treatment with or without zoledronic acid improved cortical porosity and cortical biomechanical properties (ultimate load and stiffness) and lowered parathyroid hormone (PTH). However, only calcium treatment led to the adverse effects of increased arterial calcification and fibroblast growth factor 23 (FGF23). These results suggest zoledronic acid may improve trabecular bone volume in CKD in the presence of secondary hyperparathyroidism, but does not benefit extraskeletal calcification or cortical biomechanical properties. Calcium effectively reduces PTH and benefits both cortical and trabecular bone yet increases the degree of extra skeletal calcification.
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    Epidermal growth factor receptor inhibition prevents vascular calcifying extracellular vesicle biogenesis
    (American Physiological Society, 2023) Bakhshian Nik, Amirala; Ng, Hooi Hooi; Ashbrook, Sophie K.; Sun, Patrick; Iacoviello, Francesco; Shearing, Paul R.; Bertazzo, Sergio; Mero, Deniel; Khomtchouk, Bohdan B.; Hutcheson, Joshua D.; Biomedical Engineering and Informatics, Luddy School of Informatics, Computing, and Engineering
    Chronic kidney disease (CKD) increases the risk of cardiovascular disease, including vascular calcification, leading to higher mortality. The release of calcifying extracellular vesicles (EVs) by vascular smooth muscle cells (VSMCs) promotes ectopic mineralization of vessel walls. Caveolin-1 (CAV1), a structural protein in the plasma membrane, plays a major role in calcifying EV biogenesis in VSMCs. Epidermal growth factor receptor (EGFR) colocalizes with and influences the intracellular trafficking of CAV1. Using a diet-induced mouse model of CKD followed by a high-phosphate diet to promote vascular calcification, we assessed the potential of EGFR inhibition to prevent vascular calcification. Furthermore, we computationally analyzed 7,651 individuals in the Multi-Ethnic Study of Atherosclerosis (MESA) and Framingham cohorts to assess potential correlations between coronary artery calcium and single-nucleotide polymorphisms (SNPs) associated with elevated serum levels of EGFR. Mice with CKD developed widespread vascular calcification, associated with increased serum levels of EGFR. In both the CKD mice and human VSMC culture, EGFR inhibition significantly reduced vascular calcification by mitigating the release of CAV1-positive calcifying EVs. EGFR inhibition also increased bone mineral density in CKD mice. Individuals in the MESA and Framingham cohorts with SNPs associated with increased serum EGFR exhibit elevated coronary artery calcium. Given that EGFR inhibitors exhibit clinical safety and efficacy in other pathologies, the current data suggest that EGFR may represent an ideal target to prevent pathological vascular calcification in CKD. NEW & NOTEWORTHY: Here, we investigate the potential of epidermal growth factor receptor (EGFR) inhibition to prevent vascular calcification, a leading indicator of and contributor to cardiovascular morbidity and mortality. EGFR interacts and affects the trafficking of the plasma membrane scaffolding protein caveolin-1. Previous studies reported a key role for caveolin-1 in the development of specialized extracellular vesicles that mediate vascular calcification; however, no role of EGFR has been reported. We demonstrated that EGFR inhibition modulates caveolin-1 trafficking and hinders calcifying extracellular vesicle formation, which prevents vascular calcification. Given that EGFR inhibitors are clinically approved for other indications, this may represent a novel therapeutic strategy for vascular calcification.
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    Non-Additive Effects of Combined NOX1/4 Inhibition and Calcimimetic Treatment on a Rat Model of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD)
    (Wiley, 2022-02-11) Damrath, John G.; Chen, Neal X.; Metzger, Corinne E.; Srinivasan, Shruthi; O’Neill, Kalisha; Biruete, Annabel; Avin, Keith G.; Wallace, Joseph M.; Allen, Matthew R.; Moe, Sharon M.; Medicine, School of Medicine
    Chronic kidney disease‐mineral and bone disorder (CKD‐MBD) increases cardiovascular calcification and skeletal fragility in part by increasing systemic oxidative stress and disrupting mineral homeostasis through secondary hyperparathyroidism. We hypothesized that treatments to reduce reactive oxygen species formation and reduce parathyroid hormone (PTH) levels would have additive beneficial effects to prevent cardiovascular calcification and deleterious bone architecture and mechanics before end‐stage kidney disease. To test this hypothesis, we treated a naturally progressive model of CKD‐MBD, the Cy/+ rat, beginning early in CKD with the NADPH oxidase (NOX1/4) inhibitor GKT‐137831 (GKT), the preclinical analogue of the calcimimetic etelcalcetide, KP‐2326 (KP), and their combination. The results demonstrated that CKD animals had elevated blood urea nitrogen, PTH, fibroblast growth factor 23 (FGF23), and phosphorus. Treatment with KP reduced PTH levels compared with CKD animals, whereas GKT treatment increased C‐terminal FGF23 levels without altering intact FGF23. GKT treatment alone reduced aortic calcification and NOX4 expression but did not alter the oxidative stress marker 8‐OHdG in the serum or aorta. KP treatment reduced aortic 8‐OHdG and inhibited the ability for GKT to reduce aortic calcification. Treatments did not alter heart calcification or left ventricular mass. In the skeleton, CKD animals had reduced trabecular bone volume fraction and trabecular number with increased trabecular spacing that were not improved with either treatment. The cortical bone was not altered by CKD or by treatments at this early stage of CKD. These results suggest that GKT reduces aortic calcification while KP reduces aortic oxidative stress and reduces PTH, but the combination was not additive.
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    Novel functions of circulating Klotho
    (Elsevier, 2017-07) Hum, Julia M.; O’Bryan, Linda; Smith, Rosamund C.; White, Kenneth E.; Medical and Molecular Genetics, School of Medicine
    A significant portion of the key biological functions of αKlotho (αKL) and its cognate ligand Fibroblast growth factor-23 (FGF23) have been revealed through the study of rare diseases of mineral metabolism. These findings have far reaching implications for common disorders such as chronic kidney disease-mineral bone disorder (CKD-MBD). αKL’s predominant effect on mineral homeostasis is through its actions in the kidney as a co-receptor for FGF23, however emerging data has shed light on its capacity to act as a circulating factor through the cleavage of the transmembrane form of αKL (‘mKL’) to produce ‘cleaved KL’ or ‘cKL’. This review summarizes new findings from studies using extended delivery of cKL to mouse models with phenotypes reflecting those arising in CKD-MBD.
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    The P2Y2 nucleotide receptor is an inhibitor of vascular calcification
    (Elsevier, 2017-02) Qian, Shaomin; Regan, Jenna N.; Shelton, Maxwell T.; Hoggatt, April; Mohammad, Khalid S.; Herring, Paul B.; Seye, Cheikh I.; Cellular and Integrative Physiology, School of Medicine
    BACKGROUND AND AIMS: Mutations in the 5'-nucleotidase ecto (NT5E) gene that encodes CD73, a nucleotidase that converts AMP to adenosine, are linked to arterial calcification. However, the role of purinergic receptor signaling in the pathology of intimal calcification is not well understood. In this study, we examined whether extracellular nucleotides acting via P2Y2 receptor (P2Y2R) modulate arterial intimal calcification, a condition highly correlated with cardiovascular morbidity. METHODS: Apolipoprotein E, P2Y2R double knockout mice (ApoE-/-P2Y2R-/-) were used to determine the effect of P2Y2R deficiency on vascular calcification in vivo. Vascular smooth muscle cells (VSMC) isolated from P2Y2R-/- mice grown in high phosphate medium were used to assess the role of P2Y2R in the conversion of VSMC into osteoblasts. Luciferase-reporter assays were used to assess the effect of P2Y2R on the transcriptional activity of Runx2. RESULTS: P2Y2R deficiency in ApoE-/- mice caused extensive intimal calcification despite a significant reduction in atherosclerosis and macrophage plaque content. The ectoenzyme apyrase that degrades nucleoside di- and triphosphates accelerated high phosphate-induced calcium deposition in cultured VSMC. Expression of P2Y2R inhibits calcification in vitro inhibited the osteoblastic trans-differentiation of VSMC. Mechanistically, expression of P2Y2R inhibited Runx2 transcriptional activation of an osteocalcin promoter driven luciferase reporter gene. CONCLUSIONS: This study reveals a role for vascular P2Y2R as an inhibitor of arterial intimal calcification and provides a new mechanistic insight into the regulation of the osteoblastic trans-differentiation of SMC through P2Y2R-mediated Runx2 antagonism. Given that calcification of atherosclerotic lesions is a significant clinical problem, activating P2Y2R may be an effective therapeutic approach for treatment or prevention of vascular calcification.