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Abstract
Vitamin D is a precursor of the steroid hormone calcitriol that is crucial for bone and mineral metabolism. Both the high prevalence of vitamin D deficiency in the general population and the identification of the vitamin D receptor in the heart and blood vessels raised interest in the potential cardiovascular effects of vitamin D. Experimental studies have demonstrated various cardiovascular protective actions of vitamin D, but vitamin D intoxication in animals is known to induce vascular calcification. In meta-analyses of epidemiological studies, vitamin D deficiency is associated with an increased cardiovascular risk. Findings from Mendelian randomization studies and randomized, controlled trials (RCTs) do not indicate significant effects of a general vitamin D supplementation on cardiovascular outcomes. Previous RCTs, however, were not adequately designed to address extraskeletal events, and did not focus on vitamin D-deficient individuals. Therefore, currently available evidence does not support cardiovascular benefits or harms of vitamin D supplementation with the commonly used doses, and whether vitamin D has cardiovascular effects in individuals with overt vitamin D deficiency remains to be evaluated. Here, we provide an update on clinical studies on vitamin D and cardiovascular risk, discuss ongoing vitamin D research, and consider the management of vitamin D deficiency from a cardiovascular health perspective.
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Moor MB, Bonny O. Ways of calcium reabsorption in the kidney. Am J Physiol Renal Physiol 2016; 310:F1337-50. [PMID: 27009338 DOI: 10.1152/ajprenal.00273.2015] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 03/17/2016] [Indexed: 11/22/2022] Open
Abstract
The role of the kidney in calcium homeostasis has been reshaped from a classic view in which the kidney was regulated by systemic calcitropic hormones such as vitamin D3 or parathyroid hormone to an organ actively taking part in the regulation of calcium handling. With the identification of the intrinsic renal calcium-sensing receptor feedback system, the regulation of paracellular calcium transport involving claudins, and new paracrine regulators such as klotho, the kidney has emerged as a crucial modulator not only of calciuria but also of calcium homeostasis. This review summarizes recent molecular and endocrine contributors to renal calcium handling and highlights the tight link between calcium and sodium reabsorption in the kidney.
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Affiliation(s)
- Matthias B Moor
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and
| | - Olivier Bonny
- Department of Pharmacology and Toxicology, University of Lausanne, Lausanne, Switzerland; and Service of Nephrology, Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
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Pleiotropic effects of vitamin D in chronic kidney disease. Clin Chim Acta 2016; 453:1-12. [PMID: 26656443 DOI: 10.1016/j.cca.2015.11.029] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2015] [Revised: 11/30/2015] [Accepted: 11/30/2015] [Indexed: 02/07/2023]
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Rapid calcitriol increase and persistent calcidiol insufficiency in the first 6 months after kidney transplantation. Nucl Med Commun 2015; 36:489-93. [PMID: 25603274 DOI: 10.1097/mnm.0000000000000265] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
INTRODUCTION Vitamin D deficiency or insufficiency is prevalent in kidney transplant recipients. Little is known about post-transplantation changes in vitamin D forms, which are essential for bone health and other health outcomes. The aim was to measure the levels of calcidiol and calcitriol during the first 6 months after kidney transplantation and examine their relation with other bone mineral metabolic parameters. PATIENTS AND METHODS A prospective study was performed on 98 patients recruited between April 2010 and June 2011. Calcidiol and calcitriol levels were measured at baseline and at days 15, 30, 90, and 180 after kidney transplantation. RESULTS Serum calcidiol levels remained persistently low: 14.3 (9-22) ng/ml at baseline and 16.3 (10.1-20.6) ng/ml at 6 months (P=0.641). At 6 months, calcidiol levels showed an inverse correlation with simultaneously measured parathyroid hormone levels. Calcidiol showed a trend to be higher in patients transplanted in spring but with no statistically significant difference. Calcitriol levels increased from 17 (13-23.7) pg/ml at baseline to 24 (16-32) pg/ml (P=0.002) in the first 2 weeks after transplantation and reached 37 (25-50) pg/ml (P=0.000) after 6 months. During the follow-up, calcitriol levels showed a significant inverse correlation with baseline fibroblast growth factor-23 levels. At month 6, calcitriol levels were inversely correlated with baseline fibroblast growth factor-23 levels and directly correlated with calcidiol levels. CONCLUSION In most patients, calcidiol levels remain low 6 months after kidney transplantation, whereas calcitriol levels rapidly return to normal. Lower calcidiol blood levels promoted lower calcitriol blood levels and higher parathyroid hormone concentrations.
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Comparison of two different vitamin D supplementation regimens with oral calcifediol in kidney transplant patients. J Nephrol 2015; 29:703-9. [PMID: 26454858 DOI: 10.1007/s40620-015-0237-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 09/17/2015] [Indexed: 01/23/2023]
Abstract
INTRODUCTION Vitamin D deficiency is prevalent in kidney transplant recipients (KTR) and recommendations on how to replenish vitamin D deposits are scarce. AIM To evaluate, in KTR, the safety and efficacy of calcifediol in two different vitamin D supplementation regimens, in order to assess the most suitable dose. PATIENTS AND METHODS Prospective observational study with two calcifediol supplementation regimens randomly prescribed by clinicians in liquid form, at 266 mcg doses, monthly or biweekly. We analyzed 168 KTR with a functioning allograft for more than 6 months. Patients receiving other vitamin D forms, calcimimetics or bisphosphonates were excluded. Before calcifediol initiation (pre-treatment levels) and after at least 3 months of treatment (post-treatment levels), we measured serum levels of 25-OH vitamin D (25(OH)D), parathyroid hormone (PTH), alkaline phosphatase (ALP), calcium (sCa), phosphate (sPO4) and creatinine (sCreat). RESULTS In the monthly group (n = 72), 25(OH)D levels increased from 14 ng/ml [interquartile range, IQR 9-22] at baseline to 31 [20-38] (p = 0.000), PTH decreased from 124 pg/ml [87-172] to 114 [78-163] (p = 0.006), while sCa and sPO4 remained stable. In the biweekly group (n = 96), 25(OH)D increased from 14 ng/ml [9-20] at baseline to 39 [28-52] (p = 0), PTH decreased from 141 pg/ml [95-221] to 112 [90-180] (p = 0.000), sCa remained stable and sPO4 increased from 3.3 ± 0.6 mg/dl to 3.5 ± 0.6 (p = 0.003). Renal function remained stable in both groups. CONCLUSION Vitamin D reposition with oral calcifediol, in a biweekly or monthly regimen, is safe and effective in improving 25(OH)D blood levels and in decreasing PTH in kidney transplant recipients.
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Liu WC, Zheng CM, Lu CL, Lin YF, Shyu JF, Wu CC, Lu KC. Vitamin D and immune function in chronic kidney disease. Clin Chim Acta 2015; 450:135-44. [PMID: 26291576 DOI: 10.1016/j.cca.2015.08.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/13/2015] [Accepted: 08/14/2015] [Indexed: 12/22/2022]
Abstract
The common causes of death in chronic kidney disease (CKD) patients are cardiovascular events and infectious disease. These patients are also predisposed to the development of vitamin D deficiency, which leads to an increased risk of immune dysfunction. Many extra-renal cells possess the capability to produce local active 1,25(OH)2D in an intracrine or paracrine fashion, even without kidney function. Vitamin D affects both the innate and adaptive immune systems. In innate immunity, vitamin D promotes production of cathelicidin and β-defensin 2 and enhances the capacity for autophagy via toll-like receptor activation as well as affects complement concentrations. In adaptive immunity, vitamin D suppresses the maturation of dendritic cells and weakens antigen presentation. Vitamin D also increases T helper (Th) 2 cytokine production and the efficiency of Treg lymphocytes but suppresses the secretion of Th1 and Th17 cytokines. In addition, vitamin D can decrease autoimmune disease activity. Vitamin D has been shown to play an important role in maintaining normal immune function and crosstalk between the innate and adaptive immune systems. Vitamin D deficiency may also contribute to deterioration of immune function and infectious disorders in CKD patients. However, it needs more evidence to support the requirements for vitamin D supplementation.
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Affiliation(s)
- Wen-Chih Liu
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, No.250, Wuxing Street, Taipei 110, Taiwan; Division of Nephrology, Department of Internal Medicine, Yonghe Cardinal Tien Hospital, No.80, Zhongxing St., Yonghe Dist., New Taipei City 234, Taiwan
| | - Cai-Mei Zheng
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, No.250, Wuxing Street, Taipei 110, Taiwan; Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, No.291, Zhongzheng Rd., Zhonghe Dist., New Taipei City 235, Taiwan
| | - Chien-Lin Lu
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, No.250, Wuxing Street, Taipei 110, Taiwan; Division of Nephrology, Department of Medicine, Shin-Kong Wu Ho-Su Memorial Hospital, No.95, Wen Chang Road, Shih Lin Dist., Taipei 111, Taiwan
| | - Yuh-Feng Lin
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, No.250, Wuxing Street, Taipei 110, Taiwan; Division of Nephrology, Department of Internal Medicine, Shuang Ho Hospital, No.291, Zhongzheng Rd., Zhonghe Dist., New Taipei City 235, Taiwan
| | - Jia-Fwu Shyu
- Department of Biology and Anatomy, National Defense Medical Center, No.161, Sec. 6, Minquan E. Rd., Neihu Dist., Taipei 114, Taiwan
| | - Chia-Chao Wu
- Division of Nephrology, Department of Medicine, Tri-Service General Hospital, National Defense Medical Center, No.325, Sec. 2, Cheng-Kung Rd., Neihu Dist., Taipei 114, Taiwan.
| | - Kuo-Cheng Lu
- Department of Medicine, Cardinal Tien Hospital, School of Medicine, Fu Jen Catholic University, No.362, Chung-Cheng Rd, Hsin-Tien Dist., New Taipei City 231, Taiwan.
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Chou CH, Chuang LY, Lu CY, Guh JY. Vitamin D-binding protein is required for the protective effects of vitamin D in renal fibroblasts and is phosphorylated in diabetic rats. Mol Cell Endocrinol 2015; 411:67-74. [PMID: 25911112 DOI: 10.1016/j.mce.2015.04.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Revised: 03/28/2015] [Accepted: 04/13/2015] [Indexed: 01/13/2023]
Abstract
Serum vitamin D is bound to vitamin D-binding protein (DBP). We studied the roles of DBP in streptozotocin-diabetic rats and high glucose (HG)-cultured cells. In diabetic rat sera, there was one upregulated (with a lower isoelectric point [pI], phosphorylated at S268, S270, S464 and T269) and one downregulated (with a higher pI, phosphorylated at S454 and S457) DBP. DBP levels with lower pI were increased in diabetic rat kidney and liver. HG (30 mM) increased DBP protein expression in NRK-49F cells and Clone-9 hepatocytes. HG decreased pI of DBP in Clone-9 hepatocytes. Moreover, DBP short hairpin ribonucleic acid attenuated 1,25-(OH)2D3-induced attenuation of HG-induced renin (but not collagen IV and fibronectin) protein expression in NRK-49F cells. Thus, DBP level is increased whereas DBP is phosphorylated in diabetic rat serum. HG increased DBP protein expression in renal fibroblasts and hepatocytes. Moreover, DBP is required for vitamin D-induced attenuation of HG-induced renin in NRK-49F cells.
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Affiliation(s)
- Chi-Hsien Chou
- Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan
| | - Lea-Yea Chuang
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Taiwan.
| | - Chi-Yu Lu
- Department of Biochemistry, College of Medicine, Kaohsiung Medical University, Taiwan
| | - Jinn-Yuh Guh
- Department of Internal Medicine, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Taiwan; Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung Medical University, Taiwan.
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Dusso AS, Gomez-Alonso C, Cannata-Andia JB. The hypercalcaemia of CYP24A1 inactivation: new ways to improve diagnosis and treatment. Clin Kidney J 2015; 8:456-8. [PMID: 26251717 PMCID: PMC4515908 DOI: 10.1093/ckj/sfv058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 06/17/2015] [Indexed: 02/06/2023] Open
Abstract
This case report presents fluoconazole efficacy to reduce hypercalcaemia and increased urinary calcium excretion in a patient with nephrocalcinosis after a long history of recurrent renal stones caused by a loss-of-function mutation of the CYP24A1 gene. The CYP24A1 gene codes for a key enzyme in the vitamin D endocrine system that protects against vitamin D toxicity by degrading the circulating excess of both 1,25-dihydroxyvitamin D, the hormonal form of vitamin D, and its precursor, 25-hydroxyvitamin D. In order to expedite the identification of this rare disorder and improve therapies to avoid its progression to nephrocalcinosis, this editorial updates the current knowledge on the frequency of CYP24A1-inactivating mutations, the features of their early clinical presentation and progression, and the pathophysiology of vitamin D activation in health and in granulomatous disorders that may help improve current treatment.
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Affiliation(s)
- Adriana S Dusso
- Bone and Mineral Research Unit , Instituto Reina Sofía de Investigación Nefrológica, REDinREN from ISCIII, Hospital Universitario Central de Asturias , Oviedo, Asturias , Spain
| | - Carlos Gomez-Alonso
- Bone and Mineral Research Unit , Instituto Reina Sofía de Investigación Nefrológica, REDinREN from ISCIII, Hospital Universitario Central de Asturias , Oviedo, Asturias , Spain
| | - Jorge B Cannata-Andia
- Bone and Mineral Research Unit , Instituto Reina Sofía de Investigación Nefrológica, REDinREN from ISCIII, Hospital Universitario Central de Asturias , Oviedo, Asturias , Spain
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Damasiewicz MJ, Toussaint ND. Is nutritional vitamin D supplementation beneficial in dialysis patients? Clin J Am Soc Nephrol 2015; 10:544-6. [PMID: 25770174 DOI: 10.2215/cjn.01780215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Matthew J Damasiewicz
- Departments of Nephrology and Medicine, Monash Medical Centre, Clayton, Victoria, Australia
| | - Nigel D Toussaint
- Department of Nephrology, Royal Melbourne Hospital, Parkville, Victoria, Australia; and Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia
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Prevalence and prognostic implications of vitamin D deficiency in chronic kidney disease. DISEASE MARKERS 2015; 2015:868961. [PMID: 25883412 PMCID: PMC4391696 DOI: 10.1155/2015/868961] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Accepted: 03/11/2015] [Indexed: 01/06/2023]
Abstract
Vitamin D is an important nutrient involved in bone mineral metabolism, and vitamin D status is reflected by serum total 25-hydroxyvitamin D (25[OH]D) concentrations. Vitamin D deficiency is highly prevalent in patients with chronic kidney disease (CKD), and nutritional vitamin D supplementation decreases elevated parathyroid hormone concentrations in subgroups of these patients. Furthermore, vitamin D is supposed to have pleiotropic effects on various diseases such as cardiovascular diseases, malignancies, infectious diseases, diabetes, and autoimmune diseases. Indeed, there is cumulative evidence showing the associations of low vitamin D with the development and progression of CKD, cardiovascular complication, and high mortality. Recently, genetic polymorphisms in vitamin D-binding protein have received great attention because they largely affect bioavailable 25(OH)D concentrations. This finding suggests that the serum total 25(OH)D concentrations would not be comparable among different gene polymorphisms and thus may be inappropriate as an index of vitamin D status. This finding may refute the conventional definition of vitamin D status based solely on serum total 25(OH)D concentrations.
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61
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Photocarcinogenesis: an epidemiologic perspective on ultraviolet light and skin cancer. Dermatol Clin 2015; 32:301-13, viii. [PMID: 24891053 DOI: 10.1016/j.det.2014.03.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Photocarcinogenesis is the result of a complex interplay between ultraviolet radiation, DNA damage, mutation formation, DNA repair, apoptosis, and the immune system. Recent trends show an increase in incidence of both melanoma and nonmelanoma skin cancers. Some individuals have a genetic predisposition toward increased risk for skin cancer, whereas others experience increased risk through ultraviolet exposure and subsequent mutation formation. The initiation and propagation pathways of melanoma and nonmelanoma skin cancers differ but have some elements in common. The increase in incidence of skin cancer has been discovered to vary among age groups and gender.
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Wu S, Wang J, Wang F, Wang L. Oral active vitamin d treatment and mortality in maintenance hemodialysis patients. Cardiorenal Med 2014; 4:217-24. [PMID: 25737686 DOI: 10.1159/000368203] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 09/02/2014] [Indexed: 12/17/2022] Open
Abstract
AIMS To analyze the relationship between oral active vitamin D treatment and mortality in maintenance hemodialysis (MHD) patients. METHODS We examined the association of oral calcitriol treatment with mortality in 156 MHD patients (80 men and 76 women; mean age: 59 ± 15 years). The survival analysis of all-cause and cardiovascular mortality was performed using the Kaplan-Meier survival and Cox proportional-hazards analyses. RESULTS In all, 108 of the 156 patients received active vitamin D treatment. The intact parathyroid hormone level was obviously lower in the patients who received active vitamin D treatment than in those who did not. Throughout the whole follow-up, overall mortality was 16.7% (26 deaths, 13 in each group). The cardiovascular mortality rates were 14.6% (8/48) in the control group and 4.6% (5/108) in the calcitriol group. The crude analysis of all-cause and cardiovascular mortality using the Kaplan-Meier curve showed a significant reduction in mortality risk for patients who received oral active vitamin D compared with those who did not receive it (p = 0.015 and 0.026, respectively). Cox's regression analysis showed that active vitamin D treatment was associated with a significantly lower risk of all-cause mortality (RR = 0.399, 95% CI 0.185-0.862, p = 0.019) and cardiovascular mortality (RR = 0.295, 95% CI 0.094-0.93, p = 0.037). However, after adjusting for potential confounding variables, oral active vitamin D therapy was no longer clearly associated with a lower risk of either all-cause or cardiovascular mortality. CONCLUSION Oral active vitamin D treatment was associated with improved survival in MHD patients. However, this survival benefit was smaller than previously reported, and a large cohort study should be performed.
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Affiliation(s)
- Shukun Wu
- Department of Nephrology, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, Chengdu, PR China
| | - Junru Wang
- Department of Nephrology, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, Chengdu, PR China
| | - Fang Wang
- Department of Nephrology, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, Chengdu, PR China
| | - Li Wang
- Department of Nephrology, Sichuan Academy of Medical Sciences, Sichuan Provincial People's Hospital, Chengdu, PR China
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Arcidiacono MV, Yang J, Fernandez E, Dusso A. The induction of C/EBPβ contributes to vitamin D inhibition of ADAM17 expression and parathyroid hyperplasia in kidney disease. Nephrol Dial Transplant 2014; 30:423-33. [PMID: 25294851 DOI: 10.1093/ndt/gfu311] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND In secondary hyperparathyroidism (SHPT), enhanced parathyroid levels of transforming growth factor-α (TGFα) increase EGF receptor (EGFR) activation causing parathyroid hyperplasia, high parathyroid hormone (PTH) and also reductions in vitamin D receptor (VDR) that limit vitamin D suppression of SHPT. Since anti-EGFR therapy is not an option in human SHPT, we evaluated ADAM17 as a therapeutic target to suppress parathyroid hyperplasia because ADAM17 is required to release mature TGFα, the most potent EGFR-activating ligand. METHODS Computer analysis of the ADAM17 promoter identified TGFα and C/EBPβ as potential regulators of the ADAM17 gene. Their regulation of ADAM17 expression, TGFα/EGFR-driven growth and parathyroid gland (PTG) enlargement were assessed in promoter-reporter assays in A431 cells and corroborated in rat and human SHPT, using erlotinib as anti-EGFR therapy to suppress TGFα signals, active vitamin D to induce C/EBPβ or the combination. RESULTS While TGFα induced ADAM17-promoter activity by 2.2-fold exacerbating TGFα/EGFR-driven growth, ectopic C/EBPβ expression completely prevented this vicious synergy. Accordingly, in advanced human SHPT, parathyroid ADAM17 levels correlated directly with TGFα and inversely with C/EBPβ. Furthermore, combined erlotinib + calcitriol treatment suppressed TGFα/EGFR-cell growth and PTG enlargement more potently than erlotinib in part through calcitriol induction of C/EBPβ to inhibit ADAM17-promoter activity, mRNA and protein. Importantly, in rat SHPT, the correction of vitamin D deficiency effectively reversed the resistance to paricalcitol induction of C/EBPβ to suppress ADAM17 expression and PTG enlargement, reducing PTH by 50%. CONCLUSION In SHPT, correction of vitamin D and calcitriol deficiency induces parathyroid C/EBPβ to efficaciously attenuate the severe ADAM17/TGFα synergy, which drives PTG enlargement and high PTH.
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Affiliation(s)
- Maria Vittoria Arcidiacono
- Renal Division, Washington University School of Medicine, St. Louis, MO, USA Division of Experimental Nephrology, IRB Lleida, Lleida, Spain
| | - Jing Yang
- Renal Division, Washington University School of Medicine, St. Louis, MO, USA
| | - Elvira Fernandez
- Division of Experimental Nephrology, IRB Lleida, Lleida, Spain Renal Division, Hospital Universitari Arnau de Vilanova, Universidad de Lleida, Lleida, Spain
| | - Adriana Dusso
- Renal Division, Washington University School of Medicine, St. Louis, MO, USA Division of Experimental Nephrology, IRB Lleida, Lleida, Spain
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Nolan KA, Brennan EP, Scholz CC, Cullen C, Ryan A, Taylor CT, Godson C. Paricalcitol protects against TGF-β1-induced fibrotic responses in hypoxia and stabilises HIF-α in renal epithelia. Exp Cell Res 2014; 330:371-381. [PMID: 25107382 DOI: 10.1016/j.yexcr.2014.07.034] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 07/25/2014] [Accepted: 07/26/2014] [Indexed: 01/12/2023]
Abstract
Epithelial injury and tubulointerstitial fibrosis (TIF) within a hypoxic microenvironment are associated with progressive loss of renal function in chronic kidney disease [CKD]. Transforming growth factor beta-1 (TGF-β1) is an important mediator of renal fibrosis. Growing evidence suggests that Vitamin D [1,25-(OH)2D] and its analogues may have a renoprotective effect in CKD. Here we examined the protective effect of the vitamin D analogue paricalcitol [PC; 19-nor-1α,3β,25-trihydroxy-9,10-secoergosta-5(Z),7(E) 22(E)-triene] on the responses of human renal epithelial cells to TGF-β1. PC attenuated TGF-β1-induced Smad 2 phosphorylation and upregulation of the Notch ligand Jagged-1, α-smooth muscle actin and thrombospondin-1 and prevented the TGF-β1-mediated loss of E-Cadherin. To mimic the hypoxic milieu of CKD we cultured renal epithelial cells in hypoxia [1% O2] and observed similar attenuation by PC of TGF-β1-induced fibrotic responses. Furthermore, in cells cultured in normoxia [21% O2], PC induced an accumulation of hypoxia-inducible transcription factors (HIF) 1α and HIF-2α in a time and concentration [1 µM-2 µM] dependent manner. Here, PC-induced HIF stabilisation was dependent on activation of the PI-3Kinase pathway. This is the first study to demonstrate regulation of the HIF pathway by PC which may have importance in the mechanism underlying renoprotection by PC.
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Affiliation(s)
- Karen A Nolan
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Eoin P Brennan
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Carsten C Scholz
- Systems Biology Ireland, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Cliodhna Cullen
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Aidan Ryan
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Cormac T Taylor
- Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
| | - Catherine Godson
- Diabetes Complications Research Centre, Conway Institute of Biomolecular and Biomedical Research, School of Medicine and Medical Science, University College Dublin, Belfield, Dublin 4, Ireland.
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de Boer IH, Sachs MC, Chonchol M, Himmelfarb J, Hoofnagle AN, Ix JH, Kremsdorf RA, Lin YS, Mehrotra R, Robinson-Cohen C, Siscovick DS, Steffes MW, Thummel KE, Tracy RP, Wang Z, Kestenbaum B. Estimated GFR and circulating 24,25-dihydroxyvitamin D3 concentration: a participant-level analysis of 5 cohort studies and clinical trials. Am J Kidney Dis 2014; 64:187-97. [PMID: 24703961 PMCID: PMC4111986 DOI: 10.1053/j.ajkd.2014.02.015] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Accepted: 02/04/2014] [Indexed: 12/24/2022]
Abstract
BACKGROUND Decreased glomerular filtration rate (GFR) leads to reduced production of 1,25-dihydroxyvitamin D3 from 25-hydroxyvitamin D3 (25[OH]D3). Effects of low GFR on vitamin D catabolism are less well understood. We tested associations of estimated GFR (eGFR) with the circulating concentration of 24,25-dihydroxyvitamin D3 (24,25[OH]2D3), the most abundant product of 25(OH)D3 catabolism, across populations with a wide range of GFRs. STUDY DESIGN Cross-sectional study. SETTING & PARTICIPANTS 9,596 participants in 5 cohort studies and clinical trials: the Diabetes Control and Complications Trial (N=1,193), Multi-Ethnic Study of Atherosclerosis (N=6,470), Cardiovascular Health Study (N=932), Seattle Kidney Study (N=289), and Hemodialysis Study (N=712). PREDICTOR eGFR. OUTCOME Circulating 24,25(OH)2D3 concentration. MEASUREMENTS GFR was estimated from serum creatinine using the Chronic Kidney Disease Epidemiology Collaboration equation. Vitamin D metabolites were measured by mass spectrometry. RESULTS Circulating 24,25(OH)2D3 concentration was correlated with circulating 25(OH)D3 concentration (Pearson r range, 0.64-0.88). This correlation was weaker with lower eGFRs. Moreover, the increment in 24,25(OH)2D3 concentration associated with higher 25(OH)D3 concentration (slope) was lower with lower eGFRs: 2.06 (95% CI, 2.01-2.10), 1.77 (95% CI, 1.74-1.81), 1.55 (95% CI, 1.48-1.62), 1.17 (95% CI, 1.05-1.29), 0.92 (95% CI, 0.74-1.10), 0.61 (95% CI, 0.22-1.00), and 0.37 (95% CI, 0.35-0.39) ng/mL of 24,25(OH)2D3 per 10 ng/mL of 25(OH)D3 for eGFRs≥90, 60-89, 45-59, 30-44, 15-29, and <15 mL/min/1.73 m2 and end-stage renal disease treated with hemodialysis, respectively. As a result, at a 25(OH)D3 concentration of 20 ng/mL, mean 24,25(OH)2D3 concentrations were 2.92 (95% CI, 2.87-2.96), 2.68 (95% CI, 2.64-2.72), 2.35 (95% CI, 2.26-2.45), 1.92 (95% CI, 1.74-2.10), 1.69 (95% CI, 1.43-1.95), 1.14 (95% CI, 0.62-1.66), and 1.04 (95% CI,1.02-1.07) ng/mL for each category, respectively. This interaction was independent of other relevant clinical characteristics. Race, diabetes, urine albumin excretion, and circulating parathyroid hormone and fibroblast growth factor 23 concentrations more modestly modified the association of 24,25(OH)2D3 with 25(OH)D3. LIMITATIONS Lack of direct pharmacokinetic measurements of vitamin D catabolism. CONCLUSIONS Lower eGFR is associated strongly with reduced vitamin D catabolism, as measured by circulating 24,25(OH)2D3 concentration.
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Affiliation(s)
- Ian H de Boer
- Division of Nephrology, Department of Medicine, Seattle, WA; Kidney Research Institute, Department of Medicine, Seattle, WA; Department of Epidemiology, University of Washington, Seattle, WA.
| | - Michael C Sachs
- Division of Nephrology, Department of Medicine, Seattle, WA; Kidney Research Institute, Department of Medicine, Seattle, WA
| | - Michel Chonchol
- Division of Nephrology, Department of Medicine, University of Colorado, Denver, CO
| | - Jonathan Himmelfarb
- Division of Nephrology, Department of Medicine, Seattle, WA; Kidney Research Institute, Department of Medicine, Seattle, WA
| | - Andrew N Hoofnagle
- Kidney Research Institute, Department of Medicine, Seattle, WA; Department of Laboratory Medicine, University of Washington, Seattle, WA
| | - Joachim H Ix
- Division of Nephrology, Department of Medicine, University of California, San Diego, San Diego, CA
| | - Robin A Kremsdorf
- Kidney Research Institute, Department of Medicine, Seattle, WA; Division of Nephrology, Department of Pediatrics, Seattle Children's Hospital, Seattle, WA
| | - Yvonne S Lin
- Department of Pharmaceutics, Department of Medicine, University of Washington, Seattle, WA
| | - Rajnish Mehrotra
- Division of Nephrology, Department of Medicine, Seattle, WA; Kidney Research Institute, Department of Medicine, Seattle, WA
| | - Cassianne Robinson-Cohen
- Division of Nephrology, Department of Medicine, Seattle, WA; Kidney Research Institute, Department of Medicine, Seattle, WA; Department of Epidemiology, University of Washington, Seattle, WA
| | - David S Siscovick
- Department of Epidemiology, University of Washington, Seattle, WA; Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA
| | - Michael W Steffes
- Department of Laboratory Medicine, University of Minnesota, Minneapolis, MN
| | - Kenneth E Thummel
- Department of Pharmaceutics, Department of Medicine, University of Washington, Seattle, WA
| | - Russell P Tracy
- Department of Laboratory Medicine, University of Vermont, Burlington, VT
| | - Zhican Wang
- Department of Pharmaceutics, Department of Medicine, University of Washington, Seattle, WA
| | - Bryan Kestenbaum
- Division of Nephrology, Department of Medicine, Seattle, WA; Kidney Research Institute, Department of Medicine, Seattle, WA; Department of Epidemiology, University of Washington, Seattle, WA
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Abstract
Chronic kidney disease (CKD) has been recognized as a significant global health problem because of the increased risk of total and cardiovascular morbidity and mortality. Vitamin D deficiency or insufficiency is common in patients with CKD, and serum levels of vitamin D appear to have an inverse correlation with kidney function. Growing evidence has indicated that vitamin D deficiency may contribute to deteriorating renal function, as well as increased morbidity and mortality in patients with CKD. Recent studies have suggested that treatment with active vitamin D or its analogues can ameliorate renal injury by reducing fibrosis, apoptosis, and inflammation in animal models; this treatment also decreases proteinuria and mortality in patients with CKD. These renoprotective effects of vitamin D treatment are far beyond its classical role in the maintenance of bone and mineral metabolism, in addition to its pleiotropic effects on extra-mineral metabolism. In this review, we discuss the altered metabolism of vitamin D in kidney disease, and the potential renoprotective mechanisms of vitamin D in experimental and clinical studies. In addition, issues regarding the effects of vitamin D treatment on clinical outcomes are discussed.
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Affiliation(s)
- Chang Seong Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
| | - Soo Wan Kim
- Department of Internal Medicine, Chonnam National University Medical School, Gwangju, Korea
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Mose FH, Vase H, Larsen T, Kancir ASP, Kosierkiewic R, Jonczy B, Hansen AB, Oczachowska-Kulik AE, Thomsen IM, Bech JN, Pedersen EB. Cardiovascular effects of cholecalciferol treatment in dialysis patients--a randomized controlled trial. BMC Nephrol 2014; 15:50. [PMID: 24661355 PMCID: PMC3994388 DOI: 10.1186/1471-2369-15-50] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2013] [Accepted: 03/20/2014] [Indexed: 12/20/2022] Open
Abstract
Background Patients on chronic dialysis are at increased risk of vitamin D deficiency. In observational studies plasma 25-hydroxyvitamin D (p-25(OH) D) levels are inversely correlated with plasma BNP and adverse cardiovascular outcomes. Whether a causal relation exists has yet to be established. The aim of this study was to test the hypothesis that cholecalciferol supplementation improves cardiac function and reduces blood pressure (BP) and pulse wave velocity (PWV) in patients on chronic dialysis. Methods In a randomized, placebo-controlled, double-blind study, we investigated the effect of 75 μg (3000 IU) cholecalciferol daily for 6 months, in patients on chronic dialysis. We performed two-dimensional echocardiography, with doppler and tissue-doppler imaging, 24-h ambulatory BP (24-h BP), PWV, augmentation index (AIx), central BP (cBP) and brain natriuretic peptide (BNP) measurements at baseline and after 6 months. Results Sixty-four patients were allocated to the study. Fifty dialysis patients with a mean age of 68 years (range: 46–88) and baseline p-25(OH) D of 28 (20;53) nmol/l completed the trial. Cholecalciferol increased left ventricular (LV) volume, but had no impact on other parameters regarding LV structure or left atrial structure. LV systolic function, LV diastolic function, PWV, cBP, AIx and BNP were not changed in placebo or cholecalciferol group at follow-up. 24-h BP decreased significantly in placebo group and tended to decrease in cholecalciferol group without any difference between treatments. Conclusion Six months of cholecalciferol treatment in patients on chronic dialysis did not improve 24-h BP, arterial stiffness or cardiac function. Trial registration NCT01312714, Registration Date: March 9, 2011.
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Affiliation(s)
- Frank H Mose
- University Clinic in Nephrology and Hypertension, Department of Medical Research and University of Aarhus, Holstebro Hospital, Holstebro, Denmark.
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Speeckaert MM, Speeckaert R, van Geel N, Delanghe JR. Vitamin D binding protein: a multifunctional protein of clinical importance. Adv Clin Chem 2014; 63:1-57. [PMID: 24783350 DOI: 10.1016/b978-0-12-800094-6.00001-7] [Citation(s) in RCA: 83] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Since the discovery of group-specific component and its polymorphism by Hirschfeld in 1959, research has put spotlight on this multifunctional transport protein (vitamin D binding protein, DBP). Besides the transport of vitamin D metabolites, DBP is a plasma glycoprotein with many important functions, including sequestration of actin, modulation of immune and inflammatory responses, binding of fatty acids, and control of bone development. A considerable DBP polymorphism has been described with a specific allele distribution in different geographic area. Multiple studies have shed light on the interesting relationship between polymorphisms of the DBP gene and the susceptibility to diseases. In this review, we give an overview of the multifunctional character of DBP and describe the clinical importance of DBP and its polymorphisms. Finally, we discuss the possibilities to use DBP as a novel therapeutic agent.
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de Brito Galvao JF, Nagode LA, Schenck PA, Chew DJ. Calcitriol, calcidiol, parathyroid hormone, and fibroblast growth factor-23 interactions in chronic kidney disease. J Vet Emerg Crit Care (San Antonio) 2013; 23:134-62. [PMID: 23566108 PMCID: PMC3677418 DOI: 10.1111/vec.12036] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2012] [Accepted: 02/05/2013] [Indexed: 12/13/2022]
Abstract
Objective To review the inter-relationships between calcium, phosphorus, parathyroid hormone (PTH), parent and activated vitamin D metabolites (vitamin D, 25(OH)-vitamin D, 1,25(OH)2-vitamin D, 24,25(OH)2-vitamin D), and fibroblast growth factor-23 (FGF-23) during chronic kidney disease (CKD) in dogs and cats. Data Sources Human and veterinary literature. Human Data Synthesis Beneficial effects of calcitriol treatment during CKD have traditionally been attributed to regulation of PTH but new perspectives emphasize direct renoprotective actions independent of PTH and calcium. It is now apparent that calcitriol exerts an important effect on renal tubular reclamation of filtered 25(OH)-vitamin D, which may be important in maintaining adequate circulating 25(OH)-vitamin D. This in turn may be vital for important pleiotropic actions in peripheral tissues through autocrine/paracrine mechanisms that impact the health of those local tissues. Veterinary Data Synthesis Limited information is available reporting the benefit of calcitriol treatment in dogs and cats with CKD. Conclusions A survival benefit has been shown for dogs with CKD treated with calcitriol compared to placebo. The concentrations of circulating 25(OH)-vitamin D have recently been shown to be low in people and dogs with CKD and are related to survival in people with CKD. Combination therapy for people with CKD using both parental and activated vitamin D compounds is common in human nephrology and there is a developing emphasis using combination treatment with activated vitamin D and renin-angiotensin-aldosterone-system (RAAS) inhibitors.
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Pilz S, Gaksch M, O'Hartaigh B, Tomaschitz A, März W. The role of vitamin D deficiency in cardiovascular disease: where do we stand in 2013? Arch Toxicol 2013; 87:2083-103. [PMID: 24173581 DOI: 10.1007/s00204-013-1152-z] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 10/22/2013] [Indexed: 12/14/2022]
Abstract
The high worldwide prevalence of vitamin D deficiency is largely the result of low sunlight exposure with subsequently limited cutaneous vitamin D production. Classic manifestations of vitamin D deficiency are linked to disturbances in bone and mineral metabolism, but the identification of the vitamin D receptor in almost every human cell suggests a broader role of vitamin D for overall and cardiovascular health. The various cardiovascular protective actions of vitamin D such as anti-diabetic and anti-hypertensive effects including renin suppression as well as protection against atherosclerosis and heart diseases are well defined in previous experimental studies. In line with this, large epidemiological studies have highlighted vitamin D deficiency as a marker of cardiovascular risk. However, randomized controlled trials (RCTs) on vitamin D have largely failed to show its beneficial effects on cardiovascular diseases and its conventional risk factors. While most prior vitamin D RCTs were not designed to assess cardiovascular outcomes, some large RCTs have been initiated to evaluate the efficacy of vitamin D supplementation on cardiovascular events in the general population. When considering the history of previous disappointing vitamin RCTs in general populations, more emphasis should be placed on RCTs among severely vitamin D-deficient populations who would most likely benefit from vitamin D treatment. At present, vitamin D deficiency can only be considered a cardiovascular risk marker, as vitamin D supplementation with doses recommended for osteoporosis treatment is neither proven to be beneficial nor harmful in cardiovascular diseases.
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Affiliation(s)
- Stefan Pilz
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Auenbruggerplatz 15, 8036, Graz, Austria,
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71
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Abstract
Vitamin D metabolism consists of both production and catabolism, which are enzymatically driven and highly regulated. Renal vitamin D metabolism requires filtration and tubular reabsorption of 25-hydroxyvitamin D and is regulated by parathyroid hormone, fibroblast growth factor-23, and 1,25-dihydroxyvitamin D. In chronic kidney disease, renal production of 1,25-dihydroxyvitamin D from 25-hydroxyvitamin D is reduced. In addition, pharmacokinetic studies and epidemiologic studies of 24,25-dihydroxyvitamin D, the most abundant product of 25-hydroxyvitamin D catabolism by CYP24A1, suggest that vitamin D catabolism also is reduced. New insights into the mechanisms and regulation of vitamin D metabolism may lead to novel approaches to assess and treat impaired vitamin D metabolism in chronic kidney disease.
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Affiliation(s)
- Cortney Bosworth
- Division of Nephrology and Kidney Research Institute, University of Washington, Seattle, WA, USA
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Gonzalez-Parra E, Rojas-Rivera J, Tuñón J, Praga M, Ortiz A, Egido J. Vitamin D receptor activation and cardiovascular disease. Nephrol Dial Transplant 2013; 27 Suppl 4:iv17-21. [PMID: 23258805 DOI: 10.1093/ndt/gfs534] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Vitamin D has been recently associated with several renal, cardiovascular and inflammatory diseases, beyond mineral metabolism and bone health. This is due in part to widespread expression of vitamin D receptor (VDR) on tissues and cells such as heart, kidney, immune cells, brain and muscle. In chronic kidney disease (CKD) and other chronic disorders, vitamin D deficiency [serum 25(OH)D <20 ng/mL] is very common and is associated with adverse outcomes. Paricalcitol, a selective activator of VDR, has demonstrated in several experimental and clinical studies of diabetic and non-diabetic CKD a favourable profile compared to other VDR activators, alone or as add-on to standard therapy. These beneficial effects are mediated by different actions such as reduction of oxidative stress, inflammation, downregulation of cardiac and renal renin expression, downregulation of calcifying genes and direct vascular protective effects. Furthermore, paricalcitol beneficial effects may be independent of baseline serum parathyroid hormone (PTH), calcium and phosphate levels. These benefits should be confirmed in large and well-designed ongoing clinical trials.
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Affiliation(s)
- Emilio Gonzalez-Parra
- Division of Nephrology and Hypertension, IIS Fundación Jiménez Díaz Autonoma University and FRIAT, Madrid, Spain
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Liu ZM, Woo J, Wu SH, Ho SC. The role of vitamin D in blood pressure, endothelial and renal function in postmenopausal women. Nutrients 2013; 5:2590-610. [PMID: 23839167 PMCID: PMC3738990 DOI: 10.3390/nu5072590] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2013] [Revised: 06/25/2013] [Accepted: 06/26/2013] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Vitamin D is a pro-hormone that plays an essential role in the vasculature and in kidney function. AIMS To review the extra-skeletal effects of vitamin D on blood pressure, endothelial and renal function with emphasis on recent findings in postmenopausal women. METHODS Included in this review was a PubMed database search for English language articles through March 2013. This review discussed the physiology and definition of vitamin D deficiency, the recent evidence for the role vitamin D in blood pressure, vascular and renal function. RESULTS Experimental and epidemiological data suggest that vitamin D plays an important role in the vasculature and in kidney function. Low vitamin D concentrations appear to significantly associate with hypertension, endothelial and renal dysfunction. However, the results of clinical trials have generally been mixed. Studies specifically conducted among postmenopausal women are limited and findings are still inconsistent. CONCLUSIONS Definitive studies are warranted to elucidate the effects of vitamin D supplementation on vascular and renal function and a more detailed work is needed to outline the route, duration and optimal dose of supplementation. It is premature to recommend vitamin D as a therapeutic option in the improvement of vascular and renal function at the current stage.
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Affiliation(s)
- Zhao-Min Liu
- Department of Medicine & Therapeutics, the Chinese University of Hong Kong, Hong Kong SAR, 999077, China; E-Mail:
| | - Jean Woo
- Department of Medicine & Therapeutics, the Chinese University of Hong Kong, Hong Kong SAR, 999077, China; E-Mail:
| | - Sheng-Hui Wu
- Division of Epidemiology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37203-1738, USA; E-Mail:
| | - Suzanne C. Ho
- Division of Epidemiology, The Jockey Club School of Public Health and Primary Care, the Chinese University of Hong Kong, Hong Kong SAR, 999077, China
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Damasiewicz MJ, Magliano DJ, Daly RM, Gagnon C, Lu ZX, Sikaris KA, Ebeling PR, Chadban SJ, Atkins RC, Kerr PG, Shaw JE, Polkinghorne KR. Serum 25-Hydroxyvitamin D Deficiency and the 5-Year Incidence of CKD. Am J Kidney Dis 2013; 62:58-66. [DOI: 10.1053/j.ajkd.2013.03.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 03/06/2013] [Indexed: 11/11/2022]
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Bellasi A, Galassi A, Salvi P, Cozzolino M. Paricalcitol and cardiorenal outcome: from the IMPACT study to clinical practice. Blood Purif 2013; 36:12-6. [PMID: 23736115 DOI: 10.1159/000350579] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Chronic kidney disease mineral bone disorders (CKD-MBD) encompass laboratory, vascular and bone abnormalities that might portend a poor prognosis in CKD. In spite of a great effort in elucidating the CKD-MBD natural history and pathogenesis, the underlying mechanisms are still largely unknown. However, a deficit in vitamin D is commonly reported as one of the first steps in CKD-MBD, and numerous epidemiological studies have associated serum vitamin D levels with different markers of cardiovascular disease and the risk of death in different populations. We herein summarize current evidence that links vitamin D deficiency to an adverse outcome and the results of the most recent clinical trials that have investigated the impact of paricalcitol supplementation on hard outcome in CKD patients.
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Affiliation(s)
- Antonio Bellasi
- Department of Nephrology and Dialysis, Azienda Ospedaliera Sant'Anna, Como, Italy.
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Ameri P, Canepa M, Milaneschi Y, Spallarossa P, Leoncini G, Giallauria F, Strait JB, Lakatta EG, Brunelli C, Murialdo G, Ferrucci L. Relationship between vitamin D status and left ventricular geometry in a healthy population: results from the Baltimore Longitudinal Study of Aging. J Intern Med 2013; 273:253-62. [PMID: 23061475 PMCID: PMC3568460 DOI: 10.1111/joim.12007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
OBJECTIVES The effects of vitamin D on the heart have been studied in patients with cardiac disease, but not in healthy persons. We investigated the relation between vitamin D status and left ventricular (LV) structure and function in community-dwelling subjects without heart disease. DESIGN The relationship between concentrations of 25-hydroxyvitamin D [25(OH)D], a marker of vitamin D reserve, and LV transthoracic echocardiography measures was analysed in 711 participants in the Baltimore Longitudinal Study of Aging who were without cardiac disease. RESULTS Mean 25(OH)D in the study population was 32.3 ± 11.4 ng mL(-1) ; only 15.5% of subjects had moderate or severe vitamin D deficiency [25(OH)D < 20 ng mL(-1) ]. Adjusting for age, body mass index, cardiovascular disease risk factors, physical activity, calcium and parathyroid hormone, 25(OH)D was positively correlated with LV thickness (β 0.095, SE 0.039, P < 0.05) and LV mass index (β 7.5, SE 2.6, P < 0.01). A significant nonlinear relation between 25(OH)D and LV concentric remodelling was observed. LV remodelling was more likely in participants with 25(OH)D levels <30 ng mL(-1) [odds ratio (OR) 1.24; 95% confidence interval (CI) 0.83-1.85] or ≥38 ng mL(-1) (OR 1.73; 95% CI 1.13-2.65), compared with those with 30-37 ng mL(-1) 25(OH)D. Consistently, LV relative wall thickness was significantly lower (P for trend=0.05), and LV diastolic internal diameter index (P for trend<0.05) and end-diastolic volume index (P for trend<0.05) were significantly higher in subjects with 30-37 ng mL(-1) 25(OH)D compared to the rest of the study population. There was a significant interaction between 25(OH)D and hypertension on the risk of LV hypertrophy (P < 0.05). CONCLUSIONS In a population-based sample of predominantly vitamin D-sufficient subjects without heart disease, LV geometry was most favourable at intermediate 25(OH)D concentrations.
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Affiliation(s)
- P Ameri
- Department of Internal Medicine, University of Genova, Genova, Italy.
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Low 25-hydroxyvitamin D: a significant risk factor for acute kidney injury in critically ill patients. Crit Care Med 2013; 40:3314-5. [PMID: 23164775 DOI: 10.1097/ccm.0b013e3182632b2c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Earlier decrease of FGF-23 and less hypophosphatemia in preemptive kidney transplant recipients. Transplantation 2012; 94:830-6. [PMID: 23018879 DOI: 10.1097/tp.0b013e318264fc08] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
BACKGROUND Levels of fibroblast growth factor (FGF)-23, a phosphaturic hormone, increase from the early stages of CKD and are dramatically elevated in dialysis patients. Excessive FGF-23 may be involved in the hypophosphatemia and inappropriately low calcitriol levels observed after kidney transplantation (KT).This prospective observational cohort study was carried out to determine whether there are any differences in the changes in FGF-23 levels after surgery in KT recipients according to whether they were or not on dialysis before transplantation and to assess the influence of FGF-23 in the development of posttransplantation hypophosphatemia. METHODS Consecutive KT recipients at the Hospital Clinic of Barcelona were recruited. Patients developing delayed graft function were excluded. Mineral metabolism parameters, including C-terminal fragment of FGF-23, intact parathyroid hormone, and 1,25(OH)(2)D(3), were measured in 72 KT recipients (58 on dialysis before transplantation and 14 preemptive transplant recipients) at baseline, on day 15, and at 1, 3, and 6 months after transplantation. No patients received treatment with calcimimetics, bisphosphonates, vitamin D, or phosphate supplementation during the follow-up. RESULTS FGF-23 decreased significantly in the first month after transplantation. Baseline and FGF-23 levels within the first posttransplantation month were lower in preemptive transplant recipients than in patients on dialysis at transplantation. Serum phosphate levels were lower in dialysis patients until the third month after transplantation. Pretransplantation FGF-23 was the main predictor of posttransplantation phosphate blood levels. CONCLUSIONS FGF-23 levels and the risk of developing posttransplantation hypophosphatemia were lower in preemptive kidney transplant recipients than in patients on dialysis before transplantation.
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Albalate M, de la Piedra C, Ortiz A, Hernández Pérez J, Rubert M, Pérez Garcia R, Zazo P, Nieto L, de Sequera P, Egido J. Risk in dosing regimens for 25-OH vitamin D supplementation in chronic haemodialysis patients. Nephron Clin Pract 2012; 121:c112-9. [PMID: 23221739 DOI: 10.1159/000345148] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 10/06/2012] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION 25-OH vitamin D (25-OHvitD) insufficiency or deficiency should be treated in haemodialysis (HD) patients, although the 25-OHvitD target, drug or dosing regimens are unclear. AIMS To describe factors associated with 25-OHvitD levels in HD patients and to assess the effect of three dosing regimens to supplement 25-OHvitD (calcifediol) on serum calcium (Ca), phosphate (P), parathyroid hormone (PTH), 25-OHvitD and 1,25-OHvitD. METHODS Two hundred and seventeen patients from three HD units were studied. Demographic and biochemical data were collected at baseline. Two different 25-OHvitD assays were used. One hundred and sixty-seven patients were treated with various calcifediol dosing regimens. The same biochemical determinations were repeated after 3 months of treatment. RESULTS At baseline, 12.9% of patients had 25-OHvitD <10 ng/ml. In multivariate linear regression, the season (lower in winter) and the assay method were determinants of 25-OHvitD concentration. Following calcifediol supplementation, 25-OHvitD, calcium and phosphate increased, while PTH diminished with statistical significance. After treatment, there were positive correlations between 25-OHvitD and Ca (r = 0.28, p < 0.0001) or 1,25-OHvitD (r = 0.75, p < 0.0001) that were not observed in the baseline dataset. High concentrations of post-treatment 25-OHvitD were associated with higher 1,25-OHvitD levels. Calcemia increased more in those treated with concomitant active vitamin D or those having suppressed baseline PTH, while PTH decreased more in those having above-target PTH levels. CONCLUSIONS Standardisation of methods to determine 25-OHvitD blood levels is needed. In HD patients, calcifediol increased 25-OHvitD, calcemia and phosphatemia and lowered PTH. Caution should be exercised with the higher calcifediol dosing regimens, especially in patients with suppressed PTH or on vitamin D receptor activators.
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Affiliation(s)
- M Albalate
- Servicio de Nefrología, Hospital Universitario Infanta Leonor, Autonoma University IIS-Fundación Jiménez Díaz, Madrid, Spain.
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Viaene L, Evenepoel P, Meijers B, Vanderschueren D, Overbergh L, Mathieu C. Uremia suppresses immune signal-induced CYP27B1 expression in human monocytes. Am J Nephrol 2012; 36:497-508. [PMID: 23171504 DOI: 10.1159/000345146] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Accepted: 10/16/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND Local production of 1,25-dihydroxyvitamin D (1,25(OH)(2)D) regulated by the CYP27B1 enzyme in monocytes contributes to the immunomodulatory effects of vitamin D. Uremia suppresses renal CYP27B1, but its impact on monocytic CYP27B1 is incompletely understood. The present study aimed to elucidate this issue and to define the pathogenic role of p-cresyl sulfate (PCS), indoxyl sulfate (IndS), and fibroblast growth factor 23 (FGF23). METHODS Resting or immune (interferon-γ + lipopolysaccharide)-stimulated THP1 cells and monocytes, isolated from healthy donors, were cultured in the presence of either healthy serum, uremic serum, PCS, IndS or FGF23. RNA expression levels for CYP27B1 and cytokines were quantified by RT-PCR and enzymatic CYP27B1 activity was measured 24 h after incubation. RESULTS Culturing THP1 cells or human monocytes in the presence of uremic serum led to higher inflammatory cytokine and CYP27B1 expression. Immune signal-induced CYP27B1 expression and activity, conversely, was impaired in the presence of uremic serum. Similar effects were observed in the presence of FGF23, although significance was reached in immune-stimulated cells only. PCS and IndS failed to show any effect. CONCLUSIONS Monocytic baseline CYP27B1 expression is increased in uremia, probably reflecting the microinflammatory state. Immune signal-induced CYP27B1 expression, conversely, is impaired in uremic conditions. Elevated FGF23 levels, but not PCS and IndS, may account, at least partly, for the dysregulation of monocytic CYP27B1 in uremia and, as such, may contribute to the high cardiovascular and infectious burden in chronic kidney disease.
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Affiliation(s)
- Liesbeth Viaene
- Department of Nephrology, KU Leuven, UZ Gasthuisberg, Leuven, Belgium
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Enhanced induction of Cyp24a1 by FGF23 but low serum 24,25-dihydroxyvitamin D in CKD: implications for therapy. Kidney Int 2012; 82:1046-9. [DOI: 10.1038/ki.2012.273] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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83
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Alvarez J, Wasse H, Tangpricha V. Vitamin D supplementation in pre-dialysis chronic kidney disease: A systematic review. DERMATO-ENDOCRINOLOGY 2012; 4:118-27. [PMID: 22928067 PMCID: PMC3427190 DOI: 10.4161/derm.20014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Vitamin D deficiency is associated with a variety of skeletal, cardiometabolic, and immunologic co-morbidities that are present in chronic kidney disease (CKD). We performed a systematic review to investigate the effects of vitamin D supplementation, in the form of ergocalciferol or cholecalciferol, on various health outcomes in early CKD. Seventeen clinical trials were identified, only two of which were randomized, placebo controlled trials. The majority of studies supplementing with > 2,000 IU/day of cholecalciferol achieved optimal vitamin D status, whereas studies supplementing with ergocalciferol were less consistent. Studies varied widely in their effects on lowering serum parathyroid hormone concentrations. Few studies investigated effects of vitamin D treatment on other clinical health indicators in early CKD. Rigorous studies are necessary to investigate optimal vitamin D dosing strategies in early CKD for the maintenance of adequate vitamin D status, management of secondary hyperparathyroidism and improvement of non-skeletal related clinical outcomes.
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84
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Wu C, Kato TS, Pronschinske K, Qiu S, Naka Y, Takayama H, Schulze-Späte U, Cremers S, Shane E, Mancini D, Schulze PC. Dynamics of bone turnover markers in patients with heart failure and following haemodynamic improvement through ventricular assist device implantation. Eur J Heart Fail 2012; 14:1356-65. [PMID: 22989867 DOI: 10.1093/eurjhf/hfs138] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS Abnormal bone metabolism and progressive demineralization have been described in patients with heart failure (HF). We hypothesized that mechanical unloading through implantation of a ventricular assist device (VAD) with subsequent haemodynamic improvement would correct abnormal bone metabolism in patients with advanced HF. METHODS AND RESULTS Serum was collected from 14 controls, 20 patients with moderate HF, 34 patients with advanced HF undergoing VAD implantation, and 34 patients at the time of VAD explantation (mean duration: 169 ± 125 days). Bone metabolism markers were measured using enzyme-linked immunosorption assay (ELISA) or chemiluminescence immunoassay (CLIA). Compared with controls, HF patients showed increased parathyroid hormone (PTH: 42 ± 19 vs. 117 ± 117 pg/mL in HF; P < 0.02) with decreased 25-hydroxyvitamin D [25(OH)D: 29 ± 14 vs. 21 ± 11 ng/mL in HF; P = 0.05]. While procollagen-1 N-terminal peptide (P1NP) and osteocalcin were similar, cross-linked C- and N-telopeptides of type I collagen (CTX and NTX) were both higher in HF (NTX: 14 ± 6 vs. 20 ± 11 ng/mL; P < 0.05; CTX: 0.35 ± 0.13 vs. 1.05 ± 0.78 ng/mL; P < 0.01 for controls and HF, respectively). P1NP increased markedly after VAD implantation (49 ± 37 vs. 121 ± 62 ng/mL; P < 0.0001), with a mild decrease in CTX and NTX levels indicating a shift towards anabolic bone formation. Serum PTH correlated with estimated glomerular filtration rate (r = -0.245, P < 0.05). CONCLUSION Patients with advanced HF are characterized by increased levels of biochemical markers of bone resorption potentially as a result of secondary hyperparathyroidism and uncoupling of bone remodelling. Haemodynamic improvement and mechanical unloading after VAD implantation lead to correction of bone metabolism and increased levels of anabolic bone formation markers.
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Affiliation(s)
- Christina Wu
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York, NY 10032, USA
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85
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Alvarez JA, Law J, Coakley KE, Zughaier SM, Hao L, Shahid Salles K, Wasse H, Gutiérrez OM, Ziegler TR, Tangpricha V. High-dose cholecalciferol reduces parathyroid hormone in patients with early chronic kidney disease: a pilot, randomized, double-blind, placebo-controlled trial. Am J Clin Nutr 2012; 96:672-9. [PMID: 22854402 PMCID: PMC3417221 DOI: 10.3945/ajcn.112.040642] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Vitamin D deficiency contributes to secondary hyperparathyroidism, which occurs early in chronic kidney disease (CKD). OBJECTIVES We aimed to determine whether high-dose cholecalciferol supplementation for 1 y in early CKD is sufficient to maintain optimal vitamin D status (serum 25-hydroxyvitamin D [25(OH)D] concentration ≥30 ng/mL) and decrease serum parathyroid hormone (PTH). A secondary aim was to determine the effect of cholecalciferol on blood pressure and serum fibroblast growth factor-23 (FGF23). DESIGN This was a double-blind, randomized, placebo-controlled trial. Forty-six subjects with early CKD (stages 2-3) were supplemented with oral cholecalciferol (vitamin D group; 50,000 IU/wk for 12 wk followed by 50,000 IU every other week for 40 wk) or a matching placebo for 1 y. RESULTS By 12 wk, serum 25(OH)D increased in the vitamin D group only [baseline (mean ± SD): 26.7 ± 6.8 to 42.8 ± 16.9 ng/mL; P < 0.05] and remained elevated at 1 y (group-by-time interaction: P < 0.001). PTH decreased from baseline only in the vitamin D group (baseline: 89.1 ± 49.3 to 70.1 ± 24.8 pg/mL; P = 0.01) at 12 wk, but values were not significantly different from baseline at 1 y (75.4 ± 29.5 pg/mL; P = 0.16; group-by-time interaction: P = 0.09). Group differences were more pronounced in participants with secondary hyperparathyroidism (group-by-time interaction: P = 0.004). Blood pressure and FGF23 did not change in either group. CONCLUSIONS After 1 y, this oral cholecalciferol regimen was safe and sufficient to maintain serum 25(OH)D concentrations and prevent vitamin D insufficiency in early CKD. Furthermore, serum PTH improved after cholecalciferol treatment, particularly in patients who had secondary hyperparathyroidism.
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Affiliation(s)
- Jessica A Alvarez
- Division of Endocrinology, Metabolism, and Lipids, Emory University School of Medicine, Atlanta, GA, USA
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Paricalcitol does not improve glucose metabolism in patients with stage 3-4 chronic kidney disease. Kidney Int 2012; 83:323-30. [PMID: 22913981 PMCID: PMC3509239 DOI: 10.1038/ki.2012.311] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Patients with chronic kidney disease are often insulin resistant and glucose intolerant--abnormalities that promote cardiovascular disease. Administration of 1,25-dihydroxyvitamin D (calcitriol) has improved glucose metabolism in patients with end-stage renal disease. We conducted a randomized, placebo-controlled clinical trial to test whether paricalcitol, a 1,25-dihydroxyvitamin D analog, changes glucose tolerance in earlier stages of chronic kidney disease. In a crossover design, 22 nondiabetic patients with estimated glomerular filtration rates of stage 3-4 chronic kidney disease and fasting plasma glucose of 100-125 mg/dl were given daily oral paricalcitol for 8 weeks and matching placebo for 8 weeks, separated by an 8-week washout period. The order of interventions was random and blinded to both participants and investigators. Paricalcitol significantly reduced serum concentrations of parathyroid hormone, 1,25-dihydroxyvitamin D, and 25-hydroxyvitamin D while significantly increasing serum concentrations of fibroblast growth factor-23 and 24,25-dihydroxyvitamin D. Paricalcitol, however, had no significant effect on glucose tolerance (the primary outcome measure), insulin sensitivity, beta-cell insulin response, plasma free fatty acid suppression, or urinary F2-isoprostane excretion. Thus, despite substantial effects on vitamin D metabolism, paricalcitol did not improve glucose metabolism in nondiabetic patients with stage 3-4 chronic kidney disease.
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Marckmann P, Agerskov H, Thineshkumar S, Bladbjerg EM, Sidelmann JJ, Jespersen J, Nybo M, Rasmussen LM, Hansen D, Scholze A. Randomized controlled trial of cholecalciferol supplementation in chronic kidney disease patients with hypovitaminosis D. Nephrol Dial Transplant 2012; 27:3523-31. [PMID: 22822092 DOI: 10.1093/ndt/gfs138] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Hypovitaminosis D is common in chronic kidney disease (CKD). Effects of 25-hydroxyvitamin D replenishment in CKD are not well described. METHODS An 8-week randomized, placebo-controlled, double-blind parallel intervention study was conducted in haemodialysis (HD) and non-HD CKD patients. Treatment consisted of 40,000 IU of cholecalciferol orally per week. Plasma 25-hydroxyvitamin D (25-OHD), plasma 1,25-dihydroxyvitamin D (1,25-diOHD), plasma parathyroid hormone (PTH), serum phosphate, ionized serum calcium and serum fibroblast growth factor 23 (FGF-23) were analysed. We also investigated biomarkers related to cardiovascular disease (plasma D-dimer, plasma fibrinogen, plasma von Willebrand factor antigen and activity, plasma interleukin 6, plasma C-reactive protein, blood pressure, aortic augmentation index, aortic pulse wave velocity and 24-h urinary protein loss). Objective and subjective health variables were assessed (muscle function tests, visual analogue scores and Health Assessment Questionnaire). RESULTS Fifty-two CKD patients with 25-OHD <50 nmol/L at screening were included. Cholecalciferol supplementation led to a significant increase to a median of 155 nmol/L 25-OHD (interquartile range 137-173 nmol/L) in treated patients (n = 25, P < 0.001). In non-HD patients, we saw a significant increase in 1,25-diOHD (n = 13, P < 0.01) and a lowering of PTH (n = 13, P < 0.001). This was not observed in HD patients. Cholecalciferol supplementation caused a significant increase in serum calcium and FGF-23. CONCLUSIONS 25-OHD replenishment was effectively obtained with the employed cholecalciferol dosing. In non-HD patients, it had favourable effects on 1,25-diOHD and PTH. Vitamin D-supplemented patients must be monitored for hypercalcaemia. The present study could not identify significant pleiotropic effects of 25-OHD replenishment.
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Affiliation(s)
- Peter Marckmann
- Clinical Research Unit, Department of Nephrology, Odense University Hospital, Odense, Denmark.
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89
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Damasiewicz MJ, Magliano DJ, Daly RM, Gagnon C, Lu ZX, Ebeling PR, Chadban SJ, Atkins RC, Kerr PG, Shaw JE, Polkinghorne KR. 25-Hydroxyvitamin D levels and chronic kidney disease in the AusDiab (Australian Diabetes, Obesity and Lifestyle) study. BMC Nephrol 2012; 13:55. [PMID: 22759247 PMCID: PMC3441805 DOI: 10.1186/1471-2369-13-55] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 06/21/2012] [Indexed: 01/26/2023] Open
Abstract
Background Low 25-hydroxy vitamin D (25(OH)D) levels have been associated with an increased risk of albuminuria, however an association with glomerular filtration rate (GFR) is not clear. We explored the relationship between 25(OH)D levels and prevalent chronic kidney disease (CKD), albuminuria and impaired GFR, in a national, population-based cohort of Australian adults (AusDiab Study). Methods 10,732 adults ≥25 years of age participating in the baseline survey of the AusDiab study (1999–2000) were included. The GFR was estimated using an enzymatic creatinine assay and the CKD-EPI equation, with CKD defined as eGFR <60 ml/min/1.73 m2. Albuminuria was defined as a spot urine albumin to creatinine ratio (ACR) of ≥2.5 mg/mmol for men and ≥3.5 for women. Serum 25(OH)D levels of <50 nmol/L were considered vitamin D deficient. The associations between 25(OH)D level, albuminuria and impaired eGFR were estimated using multivariate regression models. Results 30.7% of the study population had a 25(OH)D level <50 nmol/L (95% CI 25.6-35.8). 25(OH)D deficiency was significantly associated with an impaired eGFR in the univariate model (OR 1.52, 95% CI 1.07-2.17), but not in the multivariate model (OR 0.95, 95% CI 0.67-1.35). 25(OH)D deficiency was significantly associated with albuminuria in the univariate (OR 2.05, 95% CI 1.58-2.67) and multivariate models (OR 1.54, 95% CI 1.14-2.07). Conclusions Vitamin D deficiency is common in this population, and 25(OH)D levels of <50 nmol/L were independently associated with albuminuria, but not with impaired eGFR. These associations warrant further exploration in prospective and interventional studies.
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Affiliation(s)
- Matthew J Damasiewicz
- Department of Nephrology, Monash Medical Centre, 246 Clayton Road, Clayton, 3168, Victoria, Australia.
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Birmingham DJ, Hebert LA, Song H, Noonan WT, Rovin BH, Nagaraja HN, Yu CY. Evidence that abnormally large seasonal declines in vitamin D status may trigger SLE flare in non-African Americans. Lupus 2012; 21:855-64. [PMID: 22433915 PMCID: PMC3839052 DOI: 10.1177/0961203312439640] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cross-sectional studies have shown that low vitamin D (25-hydroxyvitamin D (25(OH)D)) is associated with increased systemic lupus erythematosus (SLE) activity. This study is the first to assess the temporal relationship between 25(OH)D levels and onset of SLE flare. This assessment was made possible because of the specimen bank and database of the Ohio SLE Study (OSS), a longitudinal study of frequently relapsing SLE that involved regular bimonthly patient follow-up. We identified for this study 82 flares from 46 patients that were separated by at least 8 months from previous flares. Serum 25(OH)D levels were measured at 4 and 2 months before flare, and at the time of flare (a flare interval). We found that for flares occurring during low daylight months (LDM, Oct-Mar), 25(OH)D levels were decreased at the time of flare, but only in non-African American (non-AA) patients (32% decrease at flare, compared to 4 months prior, p < 0.001). To control for seasonal effects, we also measured 25(OH)D levels in the LDM "no-flare" intervals, which were intervals that matched to the same calendar months of the patients' LDM flare intervals, but that didn't end in flare (n = 24). For these matches, a significant decrease occurred in 25(OH)D levels during the flare intervals (18.1% decrease, p < 0.001), but not during the matching no-flare intervals (6.2% decrease, p = 0.411). For flares occurring during high daylight months (HDM), 25(OH)D levels changed only in non-AA patients, increasing slightly (5.6%, p = 0.010). Analysis of flare rates for the entire OSS cohort (n = 201 flares) revealed a tendency for higher flare rates during LDM compared to HDM, but again only in non-AA patients (p = 0.060). Flare rates were lower during HDM for non-AA patients compared to AA patients (p = 0.028). In conclusion, in non-AA SLE patients, unusually large declines in 25(OH)D during LDM may be mechanistically related to SLE flare, whereas relatively high 25(OH)D levels during HDM may protect against flare.
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Affiliation(s)
- D J Birmingham
- Department of Medicine and Davis Heart and Lung Research Institute, Ohio State University Medical Center, Columbus, OH 43210, USA.
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91
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Bleskestad IH, Bergrem H, Hartmann A, Godang K, Gøransson LG. Fibroblast growth factor 23 and parathyroid hormone after treatment with active vitamin D and sevelamer carbonate in patients with chronic kidney disease stage 3b, a randomized crossover trial. BMC Nephrol 2012; 13:49. [PMID: 22742720 PMCID: PMC3462711 DOI: 10.1186/1471-2369-13-49] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Accepted: 06/25/2012] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Fibroblast growth factor 23 (FGF23) is a phosphaturic hormone that is secreted from bone and serum level increases as renal function declines. Higher levels of FGF23 are associated with increased mortality in hemodialysis-patients and in patients with chronic kidney disease (CKD) stage 2-4. The use of active vitamin D and phosphate binders as recommended in international guidelines, may affect the level of FGF23 and thereby clinical outcome. We investigated the effects of a phosphate binder and active vitamin D on the serum levels of intact FGF23 (iFGF23) and intact parathyroid hormone (iPTH) in patients with CKD stage 3b (glomerular filtration rate (GFR) 30-44 ml/min/1.73 m(2)). METHODS Seven women and 14 men were included, mean age 65.6 ± 12.2 years. They were randomized in a 1:1 ratio to receive one of two treatment sequences. Group-1 (the alphacalcidol-sevelamer carbonate group): alphacalcidol 0.25 μg once daily for two weeks followed by sevelamer carbonate 800 mg TID with meals for two weeks after a two-week washout period. Group-2 (the sevelamer carbonate-alphacalcidol group): vice versa. Nineteen patients completed the study. The 25-hydroxyvitamin D level at baseline was 97.6 ± 25.0 nmol/l. RESULTS There were no treatment effects on the iFGF23 and iPTH levels overall. In group-1 the iFGF23 level was higher after treatment with alphacalcidol compared with sevelamer carbonate (mean 105.8 ± 41.6 vs. 79.1 ± 36.5 pg/ml, p = 0.047 (CI: 0.4-52.9), and the iPTH level was lower (median: 26.5, range: 14.6-55.2 vs. median 36.1, range 13.4-106.9 pg/ml, p = 0.011). In group-2 the iFGF23 level increased non-significantly after treatment with sevelamer carbonate and throughout the washout period. CONCLUSIONS In this crossover trial with alphacalcidol and sevelamer carbonate in patients with CKD stage 3b, the levels of iFGF23 were not significantly different after the two treatments. However, in the group of patients initiating therapy with sevelamer carbonate the iFGF23 levels seemed to increase while this response was mitigated in the group of patients given alphacalcidol followed by sevelamer carbonate. This may have therapeutic implications on choice of first line therapy. The number of patients is small and this conclusion is in part based on subgroup analysis. It is therefore important that these results are confirmed in larger studies. TRIAL REGISTRATION TRIAL REGISTRATION NUMBER European Clinical Trial Database (EudraCT) 2010-020415-36 and Clinical Trials.gov NCT01231438.
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Affiliation(s)
- Inger H Bleskestad
- Department of Medicine, Stavanger University Hospital, Stavanger, Norway.
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92
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93
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González-Parra E, Avila PJ, Mahillo-Fernández I, Lentisco C, Gracia C, Egido J, Ortiz A. High prevalence of winter 25-hydroxyvitamin D deficiency despite supplementation according to guidelines for hemodialysis patients. Clin Exp Nephrol 2012; 16:945-51. [PMID: 22644091 DOI: 10.1007/s10157-012-0642-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 04/23/2012] [Indexed: 01/07/2023]
Abstract
BACKGROUND There are seasonal variations in serum 25-hydroxyvitamin D (25OHD) levels related to sun exposure. Recent guidelines suggest a target serum 25OHD level >30 ng/ml in chronic kidney disease patients. However, vitamin D supplementation dosing and monitoring regimens are not well established in hemodialysis patients. The aim of this study was to assess the interplay between season and 25OHD supplementation according to guidelines on 25OHD levels in hemodialysis patients. METHODS We retrospectively reviewed data collected prospectively over 12 months in 32 stable hemodialysis patients receiving 25OHD supplements (mean dose 30,600 IU/month) under routine clinical care following the Spanish Society of Nephrology guidelines. RESULTS Higher serum 25OHD was observed during the summer, peaking in June and August. Despite a trend towards a higher 25OHD dose in winter the prevalence of 25OHD deficiency was still >40 % in winter. Furthermore, despite a higher dose of calcium-based phosphate binders, there was a trend toward lower serum calcium in winter. Season, together with residual diuresis and dry weight, was a significant independent contributor to a multivariate lineal regression model that explained 25 % of serum 25OHD variability, while a 25OHD dose did not contribute significantly in this 25OHD-supplemented population. CONCLUSION Winter vitamin D deficiency is prevalent in hemodialysis patients despite supplementation with 25OHD according to clinical guidelines. More intensive monitoring or pre-emptive winter dose increases should be evaluated to achieve guideline targets.
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Sterling KA, Eftekhari P, Girndt M, Kimmel PL, Raj DS. The immunoregulatory function of vitamin D: implications in chronic kidney disease. Nat Rev Nephrol 2012; 8:403-12. [PMID: 22614789 DOI: 10.1038/nrneph.2012.93] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cardiovascular and infectious diseases remain the most common causes of death among patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD). Basic science and epidemiological studies indicate that vitamin D has importance not only for cardiovascular health, but also for the immune response. Vitamin D signaling pathways regulate both innate and adaptive immunity, maintaining the associated inflammatory response within physiological limits. Levels of both the inactive as well as active form of vitamin D (25-hydroxyvitamin D and 1,25-dihydroxyvitamin D, respectively) are decreased in patients with CKD and ESRD. It is reasonable to hypothesize, therefore, that the immune dysfunction associated with vitamin D deficiency in patients with CKD and ESRD in part explains the misdirected inflammatory response and increased susceptibility to infection seen in this population. Indeed, observational studies show that vitamin D deficiency in patients with ESRD is associated with increased mortality, and treatment with vitamin D is associated with a decreased risk of infection, as well as reduced all-cause mortality. However, whether different vitamin D preparations have differential effects on physiological function and clinical outcomes is still unclear. A proper understanding of the immune regulatory function of vitamin D is important for the development of future therapeutic strategies.
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Affiliation(s)
- Kevin A Sterling
- Division of Renal Diseases and Hypertension, Department of Medicine, The George Washington University School of Medicine, 2150 Pennsylvania Avenue NW, Washington, DC 20037, USA
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95
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Dusso AS. Renal vitamin D receptor expression and vitamin D renoprotection. Kidney Int 2012; 81:937-939. [DOI: 10.1038/ki.2012.30] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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Doorenbos CRC, de Cuba MM, Vogt L, Kema IP, van den Born J, Gans ROB, Navis G, de Borst MH. Antiproteinuric treatment reduces urinary loss of vitamin D-binding protein but does not affect vitamin D status in patients with chronic kidney disease. J Steroid Biochem Mol Biol 2012; 128:56-61. [PMID: 21958677 DOI: 10.1016/j.jsbmb.2011.09.002] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Revised: 08/26/2011] [Accepted: 09/08/2011] [Indexed: 12/13/2022]
Abstract
Vitamin D deficiency is common in chronic kidney disease (CKD). Increased urinary loss of vitamin D binding protein (VDBP), the main transporter of 25-hydroxyvitamin D(3) in the circulation, has been postulated to contribute to vitamin D deficiency in proteinuria. To test this hypothesis we analyzed urinary and plasma levels of VDBP, 25-hydroxyvitamin D(3) and 1,25-dihydroxyvitamin D(3) from proteinuric patients, before and after antiproteinuric interventions. We performed a post-hoc analysis of a clinical trial in CKD patients (n=13, creatinine clearance median 60 (range 25-177) ml/min) subjected to the following study periods: washout (no antiproteinuric treatment, 4 weeks), lisinopril 40mg QD (ACEi, 6 weeks), or indomethacin 75mg BID (NSAID, 4 weeks) in randomized sequence. Healthy subjects screened for donation (n=10) served as controls. Plasma and urine VDBP levels were measured by ELISA, 25-hydroxyvitamin D(3) levels by LC-MS and 1,25-dihydroxyvitamin D(3) levels by radioimmunoassay. In CKD patients urinary VDBP excretion was strongly increased (median (range) 5413 (155-211,027) μg/24h) as compared to healthy controls (64 (23-111) μg/24h, p<0.001). Both NSAID and ACEi significantly decreased urinary VDBP excretion, in proportion to proteinuria reduction. Plasma VDBP, 25-hydroxyvitamin D(3) and 1,25-dihydroxyvitamin D(3) levels, however, were similar between patients and controls and not affected by antiproteinuric intervention. Urinary VDBP excretion is markedly increased in proteinuria and responds to antiproteinuric treatment. Urinary VDBP loss is not associated with plasma VDBP or vitamin D(3) levels, suggesting that urinary loss of VDBP does not affect vitamin D status.
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Affiliation(s)
- Carolina R C Doorenbos
- Department of Internal Medicine, Division of Nephrology, University Medical Center Groningen and University of Groningen, Groningen, the Netherlands
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Pilz S, Tomaschitz A, März W, Drechsler C, Ritz E, Zittermann A, Cavalier E, Pieber TR, Lappe JM, Grant WB, Holick MF, Dekker JM. Vitamin D, cardiovascular disease and mortality. Clin Endocrinol (Oxf) 2011; 75:575-84. [PMID: 21682758 DOI: 10.1111/j.1365-2265.2011.04147.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A poor vitamin D status, i.e. low serum levels of 25-hydroxyvitamin D [25(OH)D], is common in the general population. This finding is of concern not only because of the classic vitamin D effects on musculoskeletal outcomes, but also because expression of the vitamin D receptor (VDR) and vitamin D metabolizing enzymes in the heart and blood vessels suggests a role of vitamin D in the cardiovascular system. VDR-knockout mice suffer from cardiovascular disease (CVD), and various experimental studies suggest cardiovascular protection by vitamin D, including antiatherosclerotic, anti-inflammatory and direct cardio-protective actions, beneficial effects on classic cardiovascular risk factors as well as suppression of parathyroid hormone (PTH) levels. In epidemiological studies, low levels of 25(OH)D are associated with increased risk of CVD and mortality. Data from randomized controlled trials (RCTs) are sparse and have partially, but not consistently, shown some beneficial effects of vitamin D supplementation on cardiovascular risk factors (e.g. arterial hypertension). We have insufficient data on vitamin D effects on cardiovascular events, but meta-analyses of RCTs indicate that vitamin D may modestly reduce all-cause mortality. Despite accumulating data suggesting that a sufficient vitamin D status may protect against CVD, we still must wait for results of large-scale RCTs before raising general recommendations for vitamin D in the prevention and treatment of CVD. In current clinical practice, the overall risks and costs of vitamin D supplementation should be weighed against the potential adverse consequences of untreated vitamin D deficiency.
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Affiliation(s)
- Stefan Pilz
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Medical University of Graz, Graz, Austria.
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Kidney disease and vitamin D levels: 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and VDR activation. Kidney Int Suppl (2011) 2011; 1:136-141. [PMID: 25018912 PMCID: PMC4089671 DOI: 10.1038/kisup.2011.30] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
A normal vitamin D status is essential for human health. Vitamin D deficiency is a recognized risk factor for all-cause mortality in normal individuals and in chronic kidney disease (CKD) patients. The link between vitamin D deficiency and death is a defective activation of the vitamin D receptor (VDR) by 1,25-dihydroxyvitamin D (calcitriol, the vitamin D hormone) to induce/repress genes that maintain mineral homeostasis and skeletal integrity, and prevent secondary hyperparathyroidism, hypertension, immune disorders, and renal and cardiovascular (CV) damage. The kidney is the main site for the conversion of 25-hydroxyvitamin D (25D) to circulating calcitriol, and therefore essential for the health benefits of endocrine VDR activation. The kidney is also essential for the uptake of 25D from the glomerular ultrafiltrate for its recycling to the circulation to maintain serum 25D levels, extrarenal calcitriol synthesis, and the prosurvival benefits of autocrine/paracrine VDR activation. Indeed, both calcitriol and vitamin D deficiency increase progressively in the course of CKD, and associate directly with accelerated disease progression and death. Therefore, the safe correction of calcitriol and vitamin D deficiency/insufficiency is becoming a high priority among nephrologists. This review updates the pathophysiology behind 25D and calcitriol deficiency and impaired VDR activation in CKD, the adequacy of current recommendations for vitamin D supplementation, and potential markers of the efficacy of therapy to prevent or slow the development of renal and CV lesions unrelated to parathyroid hormone suppression, a knowledge required for the design of trials to obtain evidence-based recommendations for vitamin D and calcitriol replacement at all stages of CKD.
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Abstract
The aging process affects all organs, including the kidneys. As part of this process, progressive scarring and a measurable decline in renal function occur in most people over time. The improved understanding of the processes that can lead to and/or hasten scarring and loss of renal function over time parallels advances in our understanding of the aging process. Clinical factors, including hypertension, diabetes mellitus, obesity, abnormal lipid levels and vitamin D deficiency, have been associated with increasing renal sclerosis with age. In addition, tissue factors such as angiotensin II, advanced glycation end products, oxidative stress and Klotho are associated with renal aging. These associations and possible interventions, including the control of blood pressure, blood sugar, weight, diet and calorie restriction might make renal aging more preventable than inevitable.
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Abstract
In chronic kidney disease (CKD), abnormalities in vitamin D metabolism contribute to the development of mineral and skeletal disorders, elevations in parathyroid hormone (PTH), hypertension, systemic inflammation, renal and cardiovascular damage. CKD induces a progressive loss of the capacity of the kidney not only to convert 25-hydroxyvitamin D [25(OH)D] to circulating calcitriol, the vitamin D hormone, but also to maintain serum 25(OH)D levels for non-renal calcitriol synthesis. The resulting calcitriol and 25(OH)D deficiency associates directly with accelerated disease progression and death. This chapter presents our understanding of the pathophysiology behind 25(OH)D and calcitriol deficiency in CKD, of the adequacy of current recommendations for vitamin D supplementation and PTH suppression, and of potential markers of renal and cardiovascular lesions unrelated to PTH suppression, a knowledge required for the design of trials to obtain evidence-based recommendations for vitamin D and calcitriol replacement that improve outcomes at all stages of CKD.
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Affiliation(s)
- Adriana Dusso
- Division of Experimental Nephrology, IRBLleida (Lleida Institute for Biomedical Research), Avda Rovira Roure 80, Lleida, Spain.
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