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Turner ME, Beck L, Hill Gallant KM, Chen Y, Moe OW, Kuro-o M, Moe S, Aikawa E. Phosphate in Cardiovascular Disease: From New Insights Into Molecular Mechanisms to Clinical Implications. Arterioscler Thromb Vasc Biol 2024; 44:584-602. [PMID: 38205639 PMCID: PMC10922848 DOI: 10.1161/atvbaha.123.319198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2024]
Abstract
Hyperphosphatemia is a common feature in patients with impaired kidney function and is associated with increased risk of cardiovascular disease. This phenomenon extends to the general population, whereby elevations of serum phosphate within the normal range increase risk; however, the mechanism by which this occurs is multifaceted, and many aspects are poorly understood. Less than 1% of total body phosphate is found in the circulation and extracellular space, and its regulation involves multiple organ cross talk and hormones to coordinate absorption from the small intestine and excretion by the kidneys. For phosphate to be regulated, it must be sensed. While mostly enigmatic, various phosphate sensors have been elucidated in recent years. Phosphate in the circulation can be buffered, either through regulated exchange between extracellular and cellular spaces or through chelation by circulating proteins (ie, fetuin-A) to form calciprotein particles, which in themselves serve a function for bulk mineral transport and signaling. Either through direct signaling or through mediators like hormones, calciprotein particles, or calcifying extracellular vesicles, phosphate can induce various cardiovascular disease pathologies: most notably, ectopic cardiovascular calcification but also left ventricular hypertrophy, as well as bone and kidney diseases, which then propagate phosphate dysregulation further. Therapies targeting phosphate have mostly focused on intestinal binding, of which appreciation and understanding of paracellular transport has greatly advanced the field. However, pharmacotherapies that target cardiovascular consequences of phosphate directly, such as vascular calcification, are still an area of great unmet medical need.
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Affiliation(s)
- Mandy E. Turner
- Division of Cardiovascular Medicine, Department of Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
| | - Laurent Beck
- Nantes Université, CNRS, Inserm, l’institut du thorax, F-44000 Nantes, France
| | - Kathleen M Hill Gallant
- Department of Food Science and Nutrition, University of Minnesota, St. Paul, Minnesota, USA
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yabing Chen
- Department of Pathology, University of Alabama at Birmingham
- Research Department, Veterans Affairs Birmingham Medical Center, Birmingham, AL, USA
| | - Orson W Moe
- Charles and Jane Pak Center for Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Makoto Kuro-o
- Division of Anti-aging Medicine, Center for Molecular Medicine, Jichi Medical University 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan
| | - Sharon Moe
- Division of Nephrology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Elena Aikawa
- Division of Cardiovascular Medicine, Department of Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
- Division of Cardiovascular Medicine, Department of Medicine, Center for Excellence in Vascular Biology, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA
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Turner ME, Paynter AS, White CA, Mazzetti T, Ward EC, Norman PA, Munroe J, Adams MA, Holden RM. Sex Differences in Phosphate Homeostasis: Females Excrete More Phosphate and Calcium After an Oral Phosphate Challenge. J Clin Endocrinol Metab 2023; 108:909-919. [PMID: 36268820 DOI: 10.1210/clinem/dgac616] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 09/14/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT Dietary consumption of phosphate is increasing, and elevated serum phosphate is associated with increased cardiovascular disease (CVD) risk. Sex differences in phosphate homeostasis and response to changes in dietary phosphate intake, which are not captured by clinically measured analytes, may contribute to differences in CVD presentation and bone disease. OBJECTIVE To assess sex differences in acute phosphate homeostasis in response to a single oral phosphate challenge. DESIGN Cross-sectional. SETTING General community. PARTICIPANTS 78 participants (40-76 years) with measured glomerular filtration rate >60 mL/min/1.73 m2 and no clinically diagnosed CVD and 14 young healthy adults. MAIN OUTCOME MEASURES To elucidate subtle alterations in phosphate homeostasis, we employ an acute challenge whereby the hormonal response, circulating mineral levels, and urinary excretion are assessed following an oral challenge of phosphate. RESULTS Although both males and females had similar changes in circulating phosphate, calcium, and parathyroid hormone in response to the challenge, females excreted ∼1.9x more phosphate and ∼2.7x more calcium than males, despite not consuming calcium. These sex differences were recapitulated in healthy young adults. This excretion response did not correlate to age, serum phosphate, or estradiol levels. The females with greater excretion of phosphate had higher levels of bone resorption markers compared to formation markers. CONCLUSIONS Taken together, these data identify sex differences in acute phosphate homeostasis, specifically that females may mobilize and excrete endogenous sources of calcium and phosphate in response to oral phosphate compared to males. While high levels of dietary phosphate negatively impact bone, our results suggest that females may incur more risk from these diets.
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Affiliation(s)
- Mandy E Turner
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
| | - Amanda S Paynter
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
| | - Christine A White
- Department of Medicine, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Tom Mazzetti
- Department of Medicine, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Emilie C Ward
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
| | - Patrick A Norman
- KGH Research Institute, Kingston Health Sciences Centre, Kingston, ON K7L2V7, Canada
| | - Jenny Munroe
- Clinical Nutrition, Kingston Health Sciences Center, Kingston, ON K7L 2V7, Canada
| | - Michael A Adams
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
| | - Rachel M Holden
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L3N6, Canada
- Department of Medicine, Queen's University, Kingston, ON K7L 3N6, Canada
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3
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Wu KC, Cao S, Weaver CM, King NJ, Patel S, Kingman H, Sellmeyer DE, McCauley K, Li D, Lynch SV, Kim TY, Black DM, Shafer MM, Özçam M, Lin DL, Rogers SJ, Stewart L, Carter JT, Posselt AM, Schafer AL. Prebiotic to Improve Calcium Absorption in Postmenopausal Women After Gastric Bypass: A Randomized Controlled Trial. J Clin Endocrinol Metab 2022; 107:1053-1064. [PMID: 34888663 PMCID: PMC8947782 DOI: 10.1210/clinem/dgab883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Indexed: 11/19/2022]
Abstract
CONTEXT The adverse skeletal effects of Roux-en-Y gastric bypass (RYGB) are partly caused by intestinal calcium absorption decline. Prebiotics, such as soluble corn fiber (SCF), augment colonic calcium absorption in healthy individuals. OBJECTIVE We tested the effects of SCF on fractional calcium absorption (FCA), biochemical parameters, and the fecal microbiome in a post-RYGB population. METHODS Randomized, double-blind, placebo-controlled trial of 20 postmenopausal women with history of RYGB a mean 5 years prior; a 2-month course of 20 g/day SCF or maltodextrin placebo was taken orally. The main outcome measure was between-group difference in absolute change in FCA (primary outcome) and was measured with a gold standard dual stable isotope method. Other measures included tolerability, adherence, serum calciotropic hormones and bone turnover markers, and fecal microbial composition via 16S rRNA gene sequencing. RESULTS Mean FCA ± SD at baseline was low at 5.5 ± 5.1%. Comparing SCF to placebo, there was no between-group difference in mean (95% CI) change in FCA (+3.4 [-6.7, +13.6]%), nor in calciotropic hormones or bone turnover markers. The SCF group had a wider variation in FCA change than placebo (SD 13.4% vs 7.0%). Those with greater change in microbial composition following SCF treatment had greater increase in FCA (r2 = 0.72, P = 0.05). SCF adherence was high, and gastrointestinal symptoms were similar between groups. CONCLUSION No between-group differences were observed in changes in FCA or calciotropic hormones, but wide CIs suggest a variable impact of SCF that may be due to the degree of gut microbiome alteration. Daily SCF consumption was well tolerated. Larger and longer-term studies are warranted.
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Affiliation(s)
- Karin C Wu
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
- Correspondence: Karin C. Wu, MD, 1700 Owens St. RM 349, San Francisco, CA 94158, USA.
| | - Sisi Cao
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
- Department of Human Sciences, the Ohio State University, Columbus, OH 43210, USA
| | - Connie M Weaver
- Department of Nutrition Science, Purdue University, West Lafayette, IN 47907, USA
| | - Nicole J King
- Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
| | - Sheena Patel
- California Pacific Medical Center Research Institute, San Francisco, CA 94107, USA
| | - Hillary Kingman
- Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
| | - Deborah E Sellmeyer
- Department of Medicine, Stanford University School of Medicine, Palo Alto, CA 94305, USA
| | - Kathryn McCauley
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Danny Li
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Susan V Lynch
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Tiffany Y Kim
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
| | - Dennis M Black
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143, USA
| | - Martin M Shafer
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Mustafa Özçam
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Din L Lin
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Stanley J Rogers
- Department of Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Lygia Stewart
- Department of Surgery, University of California San Francisco, San Francisco, CA 94143, USA
- Surgical Services, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
| | - Jonathan T Carter
- Department of Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Andrew M Posselt
- Department of Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Anne L Schafer
- Department of Medicine, University of California San Francisco, San Francisco, CA 94143, USA
- Endocrine Research Unit, San Francisco Veterans Affairs Health Care System, San Francisco, CA 94121, USA
- Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, CA 94143, USA
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Galassi A, Ciceri P, Porata G, Iatrino R, Boni Brivio G, Fasulo E, Magagnoli L, Stucchi A, Frittoli M, Cara A, Cozzolino M. Current treatment options for secondary hyperparathyroidism in patients with stage 3 to 4 chronic kidney disease and vitamin D deficiency. Expert Opin Drug Saf 2021; 20:1333-1349. [PMID: 33993809 DOI: 10.1080/14740338.2021.1931117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Introduction: Secondary hyperparathyroidism (SHPT) represents a complication of chronic kidney disease (CKD). Vitamin D system is altered since early CKD, and vitamin D deficiency is an established trigger of SHPT. Although untreated SHPT may degenerate into tertiary hyperparathyroidism with detrimental consequences in advanced CKD, best treatments for counteracting SHPT from stage 3 CKD are still debated. Enthusiasm on prescription of vitamin D receptor activators (VDRA) in non-dialysis renal patients, has been mitigated by the risk of low bone turnover and positive calcium-phosphate balance. Nutritional vitamin D is now suggested as first-line therapy to treat SHPT with low 25(OH)D insufficiency. However, no high-grade evidence supports the best choice between ergocalciferol, cholecalciferol, and calcifediol (in its immediate or extended-release formulation).Areas covered: The review discusses available data on safety and efficacy of nutritional vitamin D, VDRA and nutritional therapy in replenishing 25(OH)D deficiency and counteracting SHPT in non-dialysis CKD patients.Expert opinion: Best treatment for low 25(OH)D and SHPT remains unknown, due to incomplete understanding of the best homeostatic, as mutable, adaptation of mineral metabolism to CKD progression. Nutritional vitamin D and nutritional therapy appear safest interventions, whenever contextualized with single-patient characteristics. VDRA should be restricted to uncontrolled SHPT by first-line therapy.
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Affiliation(s)
- Andrea Galassi
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy
| | - Paola Ciceri
- Renal Research Laboratory, Department of Nephrology, Dialysis and Renal Transplant, Fondazione IRCCS Ca' Granda, Ospedale Maggiore Policlinico and Fondazione D'Amico per La Ricerca Sulle Malattie Renali, Milan, Italy
| | - Giulia Porata
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy
| | | | - Giulia Boni Brivio
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy.,Department of Health and Science, University of Milan, Milan, Italy
| | - Eliana Fasulo
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy
| | - Lorenza Magagnoli
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy.,Department of Health and Science, University of Milan, Milan, Italy
| | - Andrea Stucchi
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy
| | - Michela Frittoli
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy.,Department of Health and Science, University of Milan, Milan, Italy
| | - Anila Cara
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy.,Department of Health and Science, University of Milan, Milan, Italy
| | - Mario Cozzolino
- Renal and Dialysis Unit, ASST Santi Paolo E Carlo, Milan, Italy.,Department of Health and Science, University of Milan, Milan, Italy
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Associations of plasma fibroblast growth factor 23 and other markers of chronic kidney disease-Mineral and bone disorder with all-cause mortality in South African patients on maintenance dialysis: A 3-year prospective cohort study. PLoS One 2019; 14:e0216656. [PMID: 31107896 PMCID: PMC6527219 DOI: 10.1371/journal.pone.0216656] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 04/25/2019] [Indexed: 12/30/2022] Open
Abstract
INTRODUCTION Few studies have linked high levels of plasma C-terminal fibroblast growth factor 23 (FGF23) with poor clinical outcomes in patients on maintenance haemodialysis (MHD), while the association between intact FGF23 and mortality in this group of patients remains inconclusive. Therefore, the aim of this study was to evaluate the association between plasma levels of intact FGF23 and mortality in dialysis patients. METHODS A prospective multicenter study involving patients undergoing dialysis at three dialysis centers in Johannesburg was undertaken between 1st October 2014 and 31st December 2017. RESULTS The study comprised 165 chronic dialysis patients (111 blacks, 54 whites) with a mean age of 46.6 ±14.2 years. During a three year follow up period, there were 46 deaths (1.03 per 100 person-years). The median plasma FGF 23 level was 382 pg/ml (interquartile range [IQR], 145-2977). In adjusted multivariable analyses, there was a non-statistically significant increase in the risk of mortality with higher quartiles of FGF 23 levels: the adjusted hazard ratios (HR) for the second, third and fourth quantiles were HR 3.20 (95% CI, 0.99-10.35; P = 0.052), HR 2.43(95% CI,0.65-9.09; P = 0.19), and HR 2.09 (95% CI, 0.66-7.32; P = 0.25),respectively. Corrected serum calcium 2.38-2.5 mmol/l [HR 2.98 (95% CI, 1.07-8.29; P = 0.04] and > 2.50 mmol/l [HR 5.50 (95% CI, 1.84-16.48; P = 0.002] were independently associated with increased risk of death. Likewise, patients with intact parathyroid hormone > 600 pg/ml had a 3.46-fold higher risk of death (HR 3.46, 95% CI, 1.22-9.82 P = 0.019). These findings persisted in time -dependent analyses. CONCLUSION Higher levels of intact FGF 23 appear not to be independently associated with all-cause mortality in our dialysis patients, while hypercalcaemia and severe hyperparathyroidism were found to be independent predictors of mortality in this cohort of patients.
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Jovanovich A, Kendrick J. Personalized Management of Bone and Mineral Disorders and Precision Medicine in End-Stage Kidney Disease. Semin Nephrol 2019; 38:397-409. [PMID: 30082059 DOI: 10.1016/j.semnephrol.2018.05.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Chronic kidney disease mineral bone disorder (CKD-MBD) is common in end-stage renal disease and is associated with an increased risk of cardiovascular morbidity and mortality. Mainstays of treatment include decreasing serum phosphorus level toward the normal range with dietary interventions and phosphate binders and treating increased parathyroid hormone levels with activated vitamin D and/or calcimimetics. There is significant variation in serum levels of mineral metabolism markers, intestinal absorption of phosphorus, and therapeutic response among individual patients and subgroups of patients with end-stage renal disease. This variation may be partly explained by polymorphisms in genes associated with calcium and phosphorus homeostasis such as the calcium-sensing receptor gene, the vitamin D-binding receptor gene, and genes associated with vascular calcification. In this review, we discuss how personalized medicine may be used for the management of CKD-MBD and how it ultimately may lead to improved clinical outcomes. Although genetic variants may seem attractive targets to tailor CKD-MBD therapy, complete understanding of how these polymorphisms function and their clinical utility and applicability to personalized medicine need to be determined.
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Affiliation(s)
- Anna Jovanovich
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO.; VA Eastern Colorado Healthcare System, Denver, CO
| | - Jessica Kendrick
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, CO..
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Laster M, Soohoo M, Streja E, Elashoff R, Jernigan S, Langman CB, Norris KC, Salusky IB, Kalantar-Zadeh K. Racial-ethnic differences in chronic kidney disease-mineral bone disorder in youth on dialysis. Pediatr Nephrol 2019; 34:107-115. [PMID: 30267239 PMCID: PMC6420309 DOI: 10.1007/s00467-018-4048-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2018] [Revised: 07/02/2018] [Accepted: 08/07/2018] [Indexed: 11/27/2022]
Abstract
BACKGROUND Studies in healthy pediatric populations and adults treated with dialysis demonstrate higher parathyroid hormone (PTH) and lower 25-hydroxyvitamin D levels in African-Americans. Despite these findings, African-Americans on dialysis demonstrate greater bone strength and a decreased risk of fracture compared to the Caucasian dialysis population. The presence of such differences in children and young adult dialysis patients is unknown. METHODS Differences in the markers of mineral and bone metabolism (MBM) were assessed in 661 incident dialysis patients (aged 1 month to < 21 years). Racial-ethnic differences in PTH, calcium, phosphate, and total alkaline phosphatase (AP) activity were analyzed over the first year of dialysis using multivariate linear mixed models. RESULTS African-American race predicted 23% higher serum PTH (95% CI, 4.7-41.3%) when compared to Caucasian patients, while Hispanic ethnicity predicted 17.5% higher PTH (95% CI, 2.3-38%). Upon gender stratification, the differences in PTH were magnified in African-American and Hispanic females: 38% (95% CI, 14.8-69.8%) and 28.8% (95% CI, 4.7-54.9%) higher PTH compared to Caucasian females. Despite higher PTH values, African-American females persistently demonstrated up to 10.9% lower serum AP activity (95% CI, - 20.6-- 0.7%). CONCLUSIONS There are racial-ethnic differences in the markers of MBM. Higher PTH is seen in African-American and Hispanic children and young adults on dialysis with a magnification of this difference amongst the female population. There is a need to consider how factors like race, ethnicity, and gender impact the goal-targeted treatment of MBM disorders.
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Affiliation(s)
- Marciana Laster
- Division of Pediatric Nephrology, David Geffen School of Medicine at UCLA, 10833 Le Conte, Box 951752, Los Angeles, CA, 90095-1752, USA
- Division of Pediatric Nephrology, Mattel Children's Hospital at UCLA, Los Angeles, CA, USA
| | - Melissa Soohoo
- Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, School of Medicine, Orange, CA, USA
| | - Elani Streja
- Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, School of Medicine, Orange, CA, USA
| | - Robert Elashoff
- Division of Pediatric Nephrology, David Geffen School of Medicine at UCLA, 10833 Le Conte, Box 951752, Los Angeles, CA, 90095-1752, USA
| | - Stephanie Jernigan
- Division of Pediatric Nephrology, Emory University School of Medicine, Atlanta, GA, USA
| | - Craig B Langman
- Feinberg School of Medicine, Northwestern University and the Anne and Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA
| | - Keith C Norris
- Division of Pediatric Nephrology, David Geffen School of Medicine at UCLA, 10833 Le Conte, Box 951752, Los Angeles, CA, 90095-1752, USA
| | - Isidro B Salusky
- Division of Pediatric Nephrology, David Geffen School of Medicine at UCLA, 10833 Le Conte, Box 951752, Los Angeles, CA, 90095-1752, USA.
- Division of Pediatric Nephrology, Mattel Children's Hospital at UCLA, Los Angeles, CA, USA.
| | - Kamyar Kalantar-Zadeh
- Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine, School of Medicine, Orange, CA, USA
- Department of Epidemiology, UCLA Fielding School of Public Health, Los Angeles, CA, USA
- Division of Nephrology and Hypertension, University of California Irvine, School of Medicine, Orange, CA, USA
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8
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Holden RM, Hétu MF, Li TY, Ward E, Couture LE, Herr JE, Christilaw E, Adams MA, Johri AM. The Heart and Kidney: Abnormal Phosphate Homeostasis Is Associated With Atherosclerosis. J Endocr Soc 2018; 3:159-170. [PMID: 30620003 PMCID: PMC6316987 DOI: 10.1210/js.2018-00311] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 11/20/2018] [Indexed: 11/19/2022] Open
Abstract
Context Phosphate has gained recognition as a risk factor for adverse cardiovascular outcomes, potentially due to accelerated vascular calcification. Fibroblast growth factor-23 (FGF-23) is a counter-regulatory hormone that increases renal phosphate excretion to maintain normal levels. Objective The purpose of the study was to determine the association of phosphate and FGF-23 to atherosclerosis. Design and Setting A prospective cohort study (n = 204) of outpatients referred for coronary angiography over of a 1-year recruitment period at the Kingston General Hospital. Intervention Blood was collected, and a focused carotid ultrasound was performed. Main Outcome Measure Degree of angiographic coronary artery disease was scored. Carotid maximum plaque height, total area, grayscale median, and tissue pixel distribution were measured. Plasma phosphate was assessed by mineral assay and FGF-23 by ELISA. Results Carotid plaque burden [total plaque area (TPA)] was associated with higher levels of phosphate (TPA, r = 0.20, P < 0.01) and FGF-23 (r = 0.19, P < 0.01). FGF-23 was associated with increased plaque % calcium-like tissue. Participants with no coronary artery disease had significantly lower phosphate levels. Phosphate was associated with higher grayscale median (GSM) in male subjects but with lower GSM in female subjects. FGF-23 was associated with increased plaque % fat in male subjects but increased plaque % calcium in female subjects. Conclusions Phosphate was independently associated with the severity of atherosclerosis in terms of plaque burden and composition. FGF-23 was associated with plaque calcification. These findings suggest that abnormal phosphate homeostasis may play an under-recognized but potentially modifiable role in cardiovascular disease.
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Affiliation(s)
- Rachel M Holden
- Department of Medicine, Queen's University, Kingston, Ontario, Canada.,Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Marie-France Hétu
- Department of Medicine, Division of Cardiology, Cardiovascular Imaging Network at Queen's University, Kingston, Ontario, Canada
| | - Terry Y Li
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Emilie Ward
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Laura E Couture
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Julia E Herr
- Department of Medicine, Division of Cardiology, Cardiovascular Imaging Network at Queen's University, Kingston, Ontario, Canada
| | - Erin Christilaw
- Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Michael A Adams
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada
| | - Amer M Johri
- Department of Biomedical and Molecular Science, Queen's University, Kingston, Ontario, Canada.,Department of Medicine, Division of Cardiology, Cardiovascular Imaging Network at Queen's University, Kingston, Ontario, Canada
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9
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Barnett MPG, Chiang VSC, Milan AM, Pundir S, Walmsley TA, Grant S, Markworth JF, Quek SY, George PM, Cameron-Smith D. Plasma elemental responses to red meat ingestion in healthy young males and the effect of cooking method. Eur J Nutr 2018; 58:1047-1054. [PMID: 29445912 DOI: 10.1007/s00394-018-1620-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 01/21/2018] [Indexed: 11/25/2022]
Abstract
PURPOSE Elemental deficiencies are highly prevalent and have a significant impact on health. However, clinical monitoring of plasma elemental responses to foods remains largely unexplored. Data from in vitro studies show that red meat (beef) is a highly bioavailable source of several key elements, but cooking method may influence this bioavailability. We therefore studied the postprandial responses to beef steak, and the effects of two different cooking methods, in healthy young males. METHODS In a randomized cross-over controlled trial, healthy males (n = 12, 18-25 years) were fed a breakfast of beef steak (270 ± 20 g) in which the meat was either pan-fried (PF) or sous-vide (SV) cooked. Baseline and postprandial blood samples were collected and the plasma concentrations of 15 elements measured by inductively coupled plasma-mass spectrometry (ICP-MS). RESULTS Concentrations of Fe and Zn changed after meal ingestion, with plasma Fe increasing (p < 0.001) and plasma Zn decreasing (p < 0.05) in response to both cooking methods. The only potential treatment effect was seen for Zn, where the postprandial area under the curve was lower in response to the SV meal (2965 ± 357) compared to the PF meal (3190 ± 310; p < 0.05). CONCLUSIONS This multi-element approach demonstrated postprandial responsiveness to a steak meal, and an effect of the cooking method used. This suggests the method would provide insight in future elemental metabolic studies to evaluate responses to meat-based meals, including longer-term interventions in more specifically defined cohorts to clearly establish the role of red meat as an important source of elements.
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Affiliation(s)
- Matthew P G Barnett
- Food Nutrition and Health Team, Food and Bio-based Products Group, AgResearch Limited, Grasslands Research Centre, Private Bag 11008, Palmerston North, 4474, New Zealand. .,The High-Value Nutrition National Science Challenge, Auckland, New Zealand. .,Riddet Institute, Palmerston North, 4442, New Zealand.
| | - Vic S C Chiang
- The Liggins Institute, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Amber M Milan
- The Liggins Institute, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Shikha Pundir
- The Liggins Institute, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Trevor A Walmsley
- Canterbury Health Laboratories, 524 Hagley Avenue, Addington, Christchurch, 8011, New Zealand
| | - Susan Grant
- Canterbury Health Laboratories, 524 Hagley Avenue, Addington, Christchurch, 8011, New Zealand
| | - James F Markworth
- The Liggins Institute, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
| | - Siew-Young Quek
- Department of Food Sciences, School of Chemical Sciences, The University of Auckland, Auckland, 1142, New Zealand
| | - Peter M George
- Canterbury Health Laboratories, 524 Hagley Avenue, Addington, Christchurch, 8011, New Zealand
| | - David Cameron-Smith
- Food and Bio-based Products Group, AgResearch Limited, Grasslands Research Centre, Palmerston North, 4442, New Zealand.,Riddet Institute, Palmerston North, 4442, New Zealand.,The Liggins Institute, The University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand
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10
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Reinhard M, Frystyk J, Randers E, Bibby BM, Ivarsen P. Postprandial Mineral Handling in Patients on Maintenance Hemodialysis. J Ren Nutr 2018; 28:175-182. [PMID: 29429792 DOI: 10.1053/j.jrn.2017.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 11/02/2017] [Accepted: 11/19/2017] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE Patients on maintenance hemodialysis (HD) are unable to compensate for an enlarged mineral load with increased excretion of calcium and phosphate in the urine. Hence, excess calcium and phosphate must be neutralized by other mechanisms to avoid toxicity. The present study examined the acute handling of a mineral load in HD patients as compared with healthy subjects. DESIGN Controlled intervention study. SUBJECTS Twelve HD patients and 12 matched healthy subjects. INTERVENTION After a weight-adjusted standardized meal, blood samples were collected for the following 9 hours for ionized calcium, phosphate, parathyroid hormone (PTH), and fibroblast growth factor-23 (FGF23). The fractional excretion of calcium and phosphate was measured in controls. The patients were not allowed to take phosphate binders 24 hours before the experiment, and the study was performed on a non-HD day. RESULTS In healthy subjects, plasma calcium and phosphate did not change significantly from baseline, whereas HD patients demonstrated a decrease in plasma phosphate from 60 to 120 minutes by maximum 10% ([6; 13%], mean [95% confidence interval], P < .001) below baseline. PTH increased in both HD patients and controls and peaked 300 minutes after the meal 11% ([4; 19%], P < .004) above baseline in both groups. No changes in FGF23 were observed in HD patients, whereas FGF23 steadily decreased in controls, reaching nadir values at the end of the study 16% ([10; 21%], P < .001) below baseline. Control subjects demonstrated an immediate postprandial increase in the fractional excretion of both calcium and phosphate CONCLUSIONS: In HD patients, the mineral load paradoxically induced a decrease in plasma phosphate, whereas ionized calcium remained unchanged although PTH increased. These findings suggest that excess calcium and phosphate may be disposed of by mineral deposition, which may include soft tissue and vascular calcification.
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Affiliation(s)
- Mark Reinhard
- Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark.
| | - Jan Frystyk
- Medical Research Laboratory, Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
| | - Else Randers
- Department of Internal Medicine, Viborg Regional Hospital, Viborg, Denmark
| | - Bo Martin Bibby
- Department of Biostatistics, Aarhus University, Aarhus, Denmark
| | - Per Ivarsen
- Department of Renal Medicine, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, Faculty of Health, Aarhus University, Aarhus, Denmark
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11
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Popp KL, Hughes JM, Martinez-Betancourt A, Scott M, Turkington V, Caksa S, Guerriere KI, Ackerman KE, Xu C, Unnikrishnan G, Reifman J, Bouxsein ML. Bone mass, microarchitecture and strength are influenced by race/ethnicity in young adult men and women. Bone 2017; 103:200-208. [PMID: 28712877 DOI: 10.1016/j.bone.2017.07.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 06/18/2017] [Accepted: 07/12/2017] [Indexed: 02/05/2023]
Abstract
UNLABELLED Lower rates of fracture in both Blacks compared to Whites, and men compared to women are not completely explained by differences in bone mineral density (BMD). Prior evidence suggests that more favorable cortical bone microarchitecture may contribute to reduced fracture rates in older Black compared to White women, however it is not known whether these differences are established in young adulthood or develop during aging. Moreover, prior studies using high-resolution pQCT (HR-pQCT) have reported outcomes from a fixed-scan location, which may confound sex- and race/ethnicity-related differences in bone structure. PURPOSE We determined differences in bone mass, microarchitecture and strength between young adult Black and White men and women. METHODS We enrolled 185 young adult (24.2±3.4yrs) women (n=51 Black, n=50 White) and men (n=34 Black, n=50 White) in this cross-sectional study. We used dual-energy X-ray absorptiometry (DXA) to determine areal BMD (aBMD) at the femoral neck (FN), total hip (TH) and lumbar spine (LS), as well as HR-pQCT to assess bone microarchitecture and failure load by micro-finite element analysis (μFEA) at the distal tibia (4% of tibial length). We used two-way ANOVA to compare bone outcomes, adjusted for age, height, weight and physical activity. RESULTS The effect of race/ethnicity on bone outcomes did not differ by sex, and the effect of sex on bone outcomes did not differ by race/ethnicty. After adjusting for covariates, Blacks had significantly greater FN, TH and LS aBMD compared to Whites (p<0.05 for all). Blacks also had greater cortical area, vBMD, and thickness, and lower cortical porosity, with greater trabecular thickness and total vBMD compared to Whites. μFEA-estimated FL was significantly higher among Blacks compared to Whites. Men had significantly greater total vBMD, trabecular thickness and cortical area and thickness, but greater cortical porosity than women, the net effects being a higher failure load in men than women. CONCLUSION These findings demonstrate that more favorable bone microarchitecture in Blacks compared to Whites and in men compared to women is established by young adulthood. Advantageous bone strength among Blacks and men likely contributes to their lower risk of fractures throughout life compared to their White and women counterparts.
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Affiliation(s)
- Kristin L Popp
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, 50 Blossom Street, THR-1051, Boston, MA 02114, USA.
| | - Julie M Hughes
- Military Performance Division, United States Army Research Institute of Environmental Medicine, 10 General Greene Ave, Natick, MA 01760, USA
| | | | - Matthew Scott
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051, Boston, MA 02114, USA
| | - Victoria Turkington
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051, Boston, MA 02114, USA
| | - Signe Caksa
- Endocrine Unit, Massachusetts General Hospital, 50 Blossom Street, THR-1051, Boston, MA 02114, USA
| | - Katelyn I Guerriere
- Military Performance Division, United States Army Research Institute of Environmental Medicine, 10 General Greene Ave, Natick, MA 01760, USA
| | - Kathryn E Ackerman
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, 50 Blossom Street, THR-1051, Boston, MA 02114, USA; Division of Sports Medicine, Boston Children's Hospital, 319 Longwood Avenue, Boston, MA, USA 02115
| | - Chun Xu
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, United States Army Medical Research and Materiel Command, 2405 Whittier Drive, Suite 200, Frederick, MD 21702, USA
| | - Ginu Unnikrishnan
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, United States Army Medical Research and Materiel Command, 2405 Whittier Drive, Suite 200, Frederick, MD 21702, USA
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, United States Army Medical Research and Materiel Command, 2405 Whittier Drive, Suite 200, Frederick, MD 21702, USA
| | - Mary L Bouxsein
- Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, 50 Blossom Street, THR-1051, Boston, MA 02114, USA; Center for Advanced Orthopedic Studies, Beth Israel Deaconess Medical Center, Harvard Medical School, One Overland Street, Boston, MA 02215, USA; Department of Orthopedic Surgery, Harvard Medical School, One Overland Street, Boston, MA, 02215, USA
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12
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Harding K, Mersha TB, Vassalotti JA, Webb FJ, Nicholas SB. Current State and Future Trends to Optimize the Care of Chronic Kidney Disease in African Americans. Am J Nephrol 2017; 46:176-186. [PMID: 28787720 PMCID: PMC5892790 DOI: 10.1159/000479481] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND African Americans (AAs) suffer the widest gaps in chronic kidney disease (CKD) outcomes compared to Caucasian Americans (CAs) and this is because of the disparities that exist in both health and healthcare. In fact, the prevalence of CKD is 3.5 times higher in AAs compared to CAs. The disparities exist at all stages of CKD. Importantly, AAs are 10 times more likely to develop hypertension-related kidney failure and 3 times more likely to progress to kidney failure compared to CAs. SUMMARY Several factors contribute to these disparities including genetic and social determinants, late referrals, poor care coordination, medication adherence, and low recruitment in clinical trials. Key Messages: The development and implementation of CKD-related evidence-based approaches, such as clinical and social determinant assessment tools for medical interventions, more widespread outreach programs, strategies to improve medication adherence, safe and effective pharmacological treatments to control or eliminate CKD, as well as the use of health information technology, and patient-engagement programs for improved CKD outcomes may help to positively impact these disparities among AAs.
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Affiliation(s)
| | - Tesfaye B. Mersha
- Department of Pediatrics, Cincinnati Children’s Hospital
Medical Center, University of Cincinnati, Cincinnati, OH
| | - Joseph A. Vassalotti
- National Kidney Foundation, Icahn School of Medicine at Mount Sinai,
New York, NY
- Division of Nephrology, Department of Medicine, Icahn School of
Medicine at Mount Sinai, New York, NY
| | - Fern J. Webb
- Department of Community Health and Family Medicine University of
Florida College of Medicine, Jacksonville, FL
| | - Susanne B. Nicholas
- Divisions of Nephrology and Endocrinology, Department of Medicine,
David Geffen School of Medicine at University of California, Los Angeles, CA,
USA
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13
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Harding K, Mersha TB, Pham PT, Waterman AD, Webb FA, Vassalotti JA, Nicholas SB. Health Disparities in Kidney Transplantation for African Americans. Am J Nephrol 2017; 46:165-175. [PMID: 28787713 DOI: 10.1159/000479480] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND The persistent challenges of bridging healthcare disparities for African Americans (AAs) in need of kidney transplantation continue to be unresolved at the national level. This healthcare disparity is multifactorial: stemming from limited kidney donors suitable for AAs; inconsistent care coordination and suboptimal risk factor control; social determinants, low socioeconomic status, reduced access to care; and mistrust of clinicians and the healthcare system. SUMMARY There are numerous opportunities to significantly lessen the disparities in kidney transplantation for AAs through the following measures: the adoption of new care and patient engagement models that include education, enhanced practice-level cultural sensitivity, and timely referral as well as increased research on the impact of the environment on genetic risk, and implementation of new transplantation-related policies. Key Messages: This systematic review describes pretransplant concerns related to access to kidney transplantation, posttransplant complications, and policy interventions to address the challenging issues associated with kidney transplantation in AAs.
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14
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Chang AR, Miller ER, Anderson CA, Juraschek SP, Moser M, White K, Henry B, Krekel C, Oh S, Charleston J, Appel LJ. Phosphorus Additives and Albuminuria in Early Stages of CKD: A Randomized Controlled Trial. Am J Kidney Dis 2017; 69:200-209. [PMID: 27865566 PMCID: PMC5263092 DOI: 10.1053/j.ajkd.2016.08.029] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 08/08/2016] [Indexed: 12/22/2022]
Abstract
BACKGROUND Little is known about the effects of phosphorus additives on patients with kidney disease. STUDY DESIGN Randomized, double-blind, crossover trial. SETTING & PARTICIPANTS 31 adults with early stages of presumed chronic kidney disease (estimated glomerular filtration rate ≥ 45mL/min/1.73m2; urine albumin-creatinine ratio sex-specific cutoff points: men ≥ 17mg/g, women ≥ 25mg/g). INTERVENTION Higher versus lower phosphorus intake for 3 weeks. Higher phosphorus intake was achieved by the addition of commercially available diet beverages and breakfast bars to diet. OUTCOMES Change in 24-hour urine albumin excretion and plasma fibroblast growth factor 23 level. MEASUREMENTS Two 24-hour urine collections and a single fasting blood draw at the end of each period. RESULTS Mean baseline values for phosphorus intake, 24-hour urine phosphorus excretion, and estimated glomerular filtration rate were 1,113±549 (SD) mg/d, 688±300mg/d, and 74.6±22.0mL/min/1.73m2. Median urine albumin excretion of 82.7 (IQR, 39.6-174.1) mg/d. Although phosphorus intake from study products increased by 993mg/d (P<0.001) during the higher compared to lower phosphorus additive period, background phosphorus intake decreased by 151mg/d (P=0.004). Higher phosphorus additive consumption increased 24-hour urine phosphorus excretion by 505 (95% CI, 381 to 629) mg/d (P<0.001), but did not significantly increase albuminuria (higher vs lower: 14.3%; 95% CI, -2.5% to 34.0%; P=0.1) or fibroblast growth factor 23 level (higher vs lower: 3.4%; 95% CI, -5.9% to 13.6%; P=0.4). LIMITATIONS Small sample size, short duration of intervention, changes in background diet during the intervention. CONCLUSIONS A 3-week consumption of higher phosphorus food additives did not significantly increase albuminuria. Further studies are needed to confirm these results.
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Affiliation(s)
- Alex R Chang
- Geisinger Health System, Division of Nephrology, Danville, PA.
| | - Edgar R Miller
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins University, Baltimore, MD; Division of General Internal Medicine, Johns Hopkins University, Baltimore, MD
| | - Cheryl A Anderson
- Department of Family and Preventive Medicine, University of California, San Diego, CA
| | - Stephen P Juraschek
- Division of General Internal Medicine, Johns Hopkins University, Baltimore, MD
| | - Melissa Moser
- Institute for Clinical and Translational Research, Johns Hopkins University, Baltimore, MD
| | - Karen White
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins University, Baltimore, MD
| | - Bobbie Henry
- Institute for Clinical and Translational Research, Johns Hopkins University, Baltimore, MD
| | - Caitlin Krekel
- Institute for Clinical and Translational Research, Johns Hopkins University, Baltimore, MD
| | - Susan Oh
- Institute for Clinical and Translational Research, Johns Hopkins University, Baltimore, MD
| | - Jeanne Charleston
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins University, Baltimore, MD; Division of General Internal Medicine, Johns Hopkins University, Baltimore, MD
| | - Lawrence J Appel
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins University, Baltimore, MD; Division of General Internal Medicine, Johns Hopkins University, Baltimore, MD
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15
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Drüeke TB, Massy ZA. Changing bone patterns with progression of chronic kidney disease. Kidney Int 2017; 89:289-302. [PMID: 26806832 DOI: 10.1016/j.kint.2015.12.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Revised: 09/04/2015] [Accepted: 09/16/2015] [Indexed: 01/01/2023]
Abstract
It is commonly held that osteitis fibrosa and mixed uremic osteodystrophy are the predominant forms of renal osteodystrophy in patients with chronic kidney disease. Osteitis fibrosa is a high-turnover bone disease resulting mainly from secondary hyperparathyroidism, and mixed uremic osteodystrophy is in addition characterized by a mineralization defect most often attributed to vitamin D deficiency. However, there is ancient and more recent evidence that in early chronic kidney disease stages adynamic bone disease characterized by low bone turnover occurs first, at least in a significant proportion of patients. This could be due to the initial predominance of bone turnover-inhibitory conditions such as resistance to the action of parathyroid hormone (PTH), reduced calcitriol levels, sex hormone deficiency, diabetes, and, last but not least, uremic toxins leading to repression of osteocyte Wnt/β-catenin signaling and increased expression of Wnt antagonists such as sclerostin, Dickkopf-1, and sFRP4. The development of high-turnover bone disease would occur only later on, when serum PTH levels are able to overcome peripheral PTH resistance and the other inhibitory factors of bone formation. Whether FGF23 and Klotho play a direct role in the transition from low- to high-turnover bone disease or participate only indirectly via regulating PTH secretion remains to be seen.
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Affiliation(s)
- Tilman B Drüeke
- Institut National de la Santé et de la Recherche Médicale (Inserm) Unité 1018, Centre de recherche en épidémiologie et santé des populations, Equipe 5, Villejuif; Paris-Sud University and University of Paris-Ouest, Versailles-Saint-Quentin-en-Yvelines; Paris, France.
| | - Ziad A Massy
- Institut National de la Santé et de la Recherche Médicale (Inserm) Unité 1018, Centre de recherche en épidémiologie et santé des populations, Equipe 5, Villejuif; Paris-Sud University and University of Paris-Ouest, Versailles-Saint-Quentin-en-Yvelines; Paris, France; Division of Nephrology, Ambroise Paré Hospital, Assistance Publique Hôpitaux de Paris, Boulogne-Billancourt/Paris; University of Paris-Ouest, Versailles-Saint-Quentin-en-Yvelines; Paris, France
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16
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Tan SJ, Smith ER, Hewitson TD, Holt SG, Toussaint ND. The importance of klotho in phosphate metabolism and kidney disease. Nephrology (Carlton) 2016; 19:439-49. [PMID: 24750549 DOI: 10.1111/nep.12268] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2014] [Indexed: 12/19/2022]
Abstract
The discovery of fibroblast growth factor-23 (FGF23) and its co-receptor α-klotho has broadened our understanding of mineral metabolism and led to a renewed research focus on phosphate homeostatic pathways in kidney disease. Expanding knowledge of these mechanisms, both in normal physiology and in pathology, identifies targets for potential interventions designed to reduce the complications of renal disease, particularly the cardiovascular sequelae. FGF23 has emerged as a major α-klotho-dependent endocrine regulator of mineral metabolism, functioning to activate vitamin D and as a phosphatonin. However, increasingly there is an appreciation that klotho may act independently as a phosphate regulator, as well as having significant activity in other key biological processes. This review outlines our current understanding of klotho, and its potential contribution to kidney disease and cardiovascular health.
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Affiliation(s)
- Sven-Jean Tan
- Department of Nephrology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia; Department of Medicine (RMH), The University of Melbourne, Melbourne, Victoria, Australia
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17
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Gutiérrez OM, Parsa A, Isakova T, Scialla JJ, Chen J, Flack JM, Nessel LC, Gupta J, Bellovich KA, Steigerwalt S, Sondheimer JH, Wright JT, Feldman HI, Kusek JW, Lash JP, Wolf M. Genetic African Ancestry and Markers of Mineral Metabolism in CKD. Clin J Am Soc Nephrol 2016; 11:653-62. [PMID: 26912553 DOI: 10.2215/cjn.08020715] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 01/05/2016] [Indexed: 01/13/2023]
Abstract
BACKGROUND AND OBJECTIVES Disorders of mineral metabolism are more common in African Americans with CKD than in European Americans with CKD. Previous studies have focused on the differences in mineral metabolism by self-reported race, making it difficult to delineate the importance of environmental compared with biologic factors. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In a cross-sectional analysis of 3013 participants of the Chronic Renal Insufficiency Cohort study with complete data, we compared markers of mineral metabolism (phosphorus, calcium, alkaline phosphatase, parathyroid hormone, fibroblast growth factor 23, and urine calcium and phosphorus excretion) in European Americans versus African Americans and separately, across quartiles of genetic African ancestry in African Americans (n=1490). RESULTS Compared with European Americans, African Americans had higher blood concentrations of phosphorus, alkaline phosphatase, fibroblast growth factor 23, and parathyroid hormone, lower 24-hour urinary excretion of calcium and phosphorus, and lower urinary fractional excretion of calcium and phosphorus at baseline (P<0.001 for all). Among African Americans, a higher percentage of African ancestry was associated with lower 24-hour urinary excretion of phosphorus (Ptrend<0.01) in unadjusted analyses. In linear regression models adjusted for socio-demographic characteristics, kidney function, serum phosphorus, and dietary phosphorus intake, higher percentage of African ancestry was significantly associated with lower 24-hour urinary phosphorus excretion (each 10% higher African ancestry was associated with 39.6 mg lower 24-hour urinary phosphorus, P<0.001) and fractional excretion of phosphorus (each 10% higher African ancestry was associated with an absolute 1.1% lower fractional excretion of phosphorus, P=0.01). CONCLUSIONS A higher percentage of African ancestry was independently associated with lower 24-hour urinary phosphorus excretion and lower fractional excretion of phosphorus among African Americans with CKD. These findings suggest that genetic variability might contribute to racial differences in urinary phosphorus excretion in CKD.
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Affiliation(s)
- Orlando M Gutiérrez
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material.
| | - Afshin Parsa
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Tamara Isakova
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Julia J Scialla
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Jing Chen
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - John M Flack
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Lisa C Nessel
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Jayanta Gupta
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Keith A Bellovich
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Susan Steigerwalt
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - James H Sondheimer
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Jackson T Wright
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Harold I Feldman
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - John W Kusek
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - James P Lash
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
| | - Myles Wolf
- Due to the number of contributing authors, the affiliations are provided in the Supplemental Material
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18
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Wasser WG, Gil A, Skorecki KL. The Envy of Scholars: Applying the Lessons of the Framingham Heart Study to the Prevention of Chronic Kidney Disease. Rambam Maimonides Med J 2015; 6:RMMJ.10214. [PMID: 26241225 PMCID: PMC4524402 DOI: 10.5041/rmmj.10214] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
During the past 50 years, a dramatic reduction in the mortality rate associated with cardiovascular disease has occurred in the US and other countries. Statistical modeling has revealed that approximately half of this reduction is the result of risk factor mitigation. The successful identification of such risk factors was pioneered and has continued with the Framingham Heart Study, which began in 1949 as a project of the US National Heart Institute (now part of the National Heart, Lung, and Blood Institute). Decreases in total cholesterol, blood pressure, smoking, and physical inactivity account for 24%, 20%, 12%, and 5% reductions in the mortality rate, respectively. Nephrology was designated as a recognized medical professional specialty a few years later. Hemodialysis was first performed in 1943. The US Medicare End-Stage Renal Disease (ESRD) Program was established in 1972. The number of patients in the program increased from 5,000 in the first year to more than 500,000 in recent years. Only recently have efforts for risk factor identification, early diagnosis, and prevention of chronic kidney disease (CKD) been undertaken. By applying the approach of the Framingham Heart Study to address CKD risk factors, we hope to mirror the success of cardiology; we aim to prevent progression to ESRD and to avoid the cardiovascular complications associated with CKD. In this paper, we present conceptual examples of risk factor modification for CKD, in the setting of this historical framework.
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Affiliation(s)
- Walter G. Wasser
- Division of Nephrology, Mayanei HaYeshua Medical Center, Bnei Brak, Israel
- Division of Nephrology, Rambam Health Care Campus, Haifa, Israel
- To whom correspondence should be addressed. E-mail:
| | - Amnon Gil
- Division of Nephrology, Carmel Medical Center, Haifa, Israel
| | - Karl L. Skorecki
- Division of Nephrology, Rambam Health Care Campus, Haifa, Israel
- Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
- Director of Medical and Research Development, Rambam Health Care Campus, Haifa, Israel
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19
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Bhagatwala J, Zhu H, Parikh SJ, Guo DH, Kotak I, Huang Y, Havens R, Pham M, Afari E, Kim S, Cutler C, Pollock NK, Dong Y, Raed A, Dong Y. Dose and time responses of vitamin D biomarkers to monthly vitamin D3 supplementation in overweight/obese African Americans with suboptimal vitamin d status: a placebo controlled randomized clinical trial. BMC OBESITY 2015. [PMID: 26217542 PMCID: PMC4511449 DOI: 10.1186/s40608-015-0056-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background A critical need exists to better understand the physiological sequel of vitamin D supplementation in obese individuals and African Americans. The aim was to comprehensively evaluate dose- and time-responses of a panel of vitamin D biomarkers to vitamin D supplements in this population. Methods We conducted a 16-week randomized, double-blinded, and placebo-controlled clinical trial. Seventy overweight/obese African Americans (age 13–45 years, 84 % females) with 25-hydroxyvitamin D [25(OH)D] concentrations ≤20 ng/mL were randomly assigned to receive a supervised monthly oral vitamin D3 of 18,000 IU (~600 IU/day, n = 17), 60,000 IU (~2000 IU/day, n = 18), 120,000 IU (~4000 IU/day, n = 18), or placebo (n = 17). Results There were significant dose- and time-responses of circulating 25(OH)D, 1,25-dihydroxyvitamin D [1,25(OH)2D], and intact parathyroid hormone (iPTH), but not fibroblast growth factor-23 (FGF-23), phosphorus and urine calcium to the vitamin D supplements. The mean 25(OH)D concentrations in the 2000 IU and 4000 IU groups reached ≥30 ng/mL as early as 8-weeks and remained at similar level at 16-weeks. The increase of 25(OH)D was significantly higher in the 4000 IU group than all the other groups at 8-weeks. The increase of 1,25(OH)2D was significantly higher in the 2000 IU and 4000 IU groups than the placebo at 8-weeks. Only the 4000 IU compared to the placebo significantly reduced iPTH at 8- and 16-weeks. Conclusions Our RCT, for the first time, comprehensively evaluated time- and dose- responses of vitamin D supplementation in overweight/obese African Americans with suboptimal vitamin D status. Circulating 25(OH)D, 1,25(OH)2D, and iPTH, but not FGF-23, phosphorus and urine calcium, respond to vitamin D supplementation in a time- and dose–response manner. By monthly dosing, 2000 IU appears to be sufficient in achieving a 25(OH)D level of 30 ng/mL in this population. However, importantly, 4000 IU, rather than 2000 IU, seems to suppress iPTH. If replicated, these data might be informative in optimizing vitamin D status and providing individualized dosing recommendation in overweight/obese African Americans. Trial registration ClinicalTrials.gov number: NCT01583621, Registered on April 3, 2012.
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Affiliation(s)
- Jigar Bhagatwala
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA ; Department of Internal Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA USA
| | - Haidong Zhu
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | - Samip J Parikh
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA ; Department of Internal Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA USA
| | - De-Huang Guo
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | - Ishita Kotak
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | - Ying Huang
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | - Robyn Havens
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA ; College of Nursing, Georgia Regents University, Augusta, GA USA
| | - Michael Pham
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | - Eric Afari
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | - Susan Kim
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | | | - Norman K Pollock
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | - Yutong Dong
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
| | - Anas Raed
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA ; Department of Internal Medicine, Medical College of Georgia, Georgia Regents University, Augusta, GA USA
| | - Yanbin Dong
- Georgia Prevention Institute, Medical College of Georgia, Georgia Regents University, Building HS-1640, Augusta, 30912-3715 GA USA
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Redmond J, Palla L, Yan L, Jarjou LMA, Prentice A, Schoenmakers I. Ethnic differences in urinary calcium and phosphate excretion between Gambian and British older adults. Osteoporos Int 2015; 26:1125-35. [PMID: 25311107 PMCID: PMC4331615 DOI: 10.1007/s00198-014-2926-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 10/01/2014] [Indexed: 12/04/2022]
Abstract
UNLABELLED Ethnic differences in renal calcium and phosphate excretion exist, which may depend on differences in their dietary intakes and regulatory factors. We report highly significant differences in urinary calcium and phosphate excretion between white British and Gambian adults after statistical adjustment for mineral intakes, indicating an independent effect of ethnicity. INTRODUCTION Populations vary in their risk of age-related osteoporosis. There are racial or ethnic differences in the metabolism of the bone-forming minerals calcium (Ca) and phosphate (P), with a lower renal Ca and P excretion in African-Americans compared to white counterparts, even at similar intakes and rates of absorption. Also, Africans in The Gambia have a lower Ca excretion compared to white British subjects, groups known to differ in their dietary Ca intake. Here, we report on differences in urinary Ca and P excretion between Gambian and white British adults while allowing for known predictors, including dietary intakes. METHODS Participants were healthy white British (n = 60) and Gambian (n = 61) men and women aged 60-75 years. Fasting blood and 2-h urine samples were collected. Markers of Ca and P metabolism were analysed. Dietary intake was assessed with country-specific methods. RESULTS White British older adults had higher creatinine-corrected urinary Ca and P excretion (uCa/uCr, uP/uCr) and lower tubular maximum of Ca and P compared to Gambian counterparts. The predictors of urinary Ca and P differed between groups. Multiple regression analysis showed that dietary Ca and Ca/P were predictors of uCa/uCr and uP/uCr, respectively. Ethnicity remained a significant predictor of uCa/uCr and uP/uCr after adjustment for diet and other factors. CONCLUSIONS Gambian older adults have higher renal Ca conservation than British counterparts. Dietary mineral intakes were predictors of the differences in urinary Ca and P excretion, but ethnicity remained a highly significant predictor after statistical adjustment. This suggests that ethnicity has an independent effect on renal Ca and P handling.
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Affiliation(s)
- J. Redmond
- Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, CB1 9NL UK
| | - L. Palla
- Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, CB1 9NL UK
- Present Address: Department of Non-communicable Disease Epidemiology, Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - L. Yan
- Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, CB1 9NL UK
| | | | - A. Prentice
- Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, CB1 9NL UK
- Medical Research Council Keneba, Keneba, The Gambia
| | - I. Schoenmakers
- Medical Research Council Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, CB1 9NL UK
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Ali FN, Falkner B, Gidding SS, Price HE, Keith SW, Langman CB. Fibroblast growth factor-23 in obese, normotensive adolescents is associated with adverse cardiac structure. J Pediatr 2014; 165:738-43.e1. [PMID: 25063724 PMCID: PMC4177448 DOI: 10.1016/j.jpeds.2014.06.027] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Revised: 05/13/2014] [Accepted: 06/09/2014] [Indexed: 12/16/2022]
Abstract
OBJECTIVES Fibroblast growth factor-23 (FGF23) is a biomarker for cardiovascular disease. Obesity may promote FGF23 production in the absence of chronic kidney disease. We sought to determine among normotensive African American adolescents whether FGF23 levels are greater in obese compared with normal-weight adolescents and to determine the relationship of FGF23 with markers of cardiac structure and insulin resistance. STUDY DESIGN Cross-sectional data were obtained from a cohort of 130 normotensive, African American adolescents ages 13-18 years without chronic kidney disease; 74 were obese; 56 were normal weight. Plasma C-terminal FGF23, fasting glucose and insulin, and high-sensitivity C-reactive protein were measured; participants underwent M-mode echocardiography. RESULTS FGF23 was skewed and approximately normally distributed after natural log transformation (logFGF23). FGF23 levels were greater in obese vs normal-weight participants (geometric mean 43 vs 23 RU/mL, P < .01). FGF23 values were significantly greater in participants with eccentric or concentric cardiac hypertrophy compared with those without hypertrophy P < .01). LogFGF23 directly correlated with body mass index, body mass index z-score, waist circumference, fasting insulin levels, and homeostasis model assessment scores. Regression models adjusted for age, sex, and high-sensitivity C-reactive protein suggest that each 10% increase in FGF23 is associated with a 1.31 unit increase in left ventricular mass (P < .01), a 0.29-unit increase in left ventricular mass index (P < .01), and a 0.01-unit increase in left atrial dimension indexed to height (P = .02). CONCLUSIONS In this sample of obese African American adolescents, FGF23 blood levels were associated with abnormal cardiac structure. We postulate that FGF23 may be an early marker of cardiac injury in obese but otherwise-healthy African American adolescents.
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Affiliation(s)
- Farah N. Ali
- Division of Kidney Diseases, Ann & Robert H. Lurie Children’s Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Bonita Falkner
- Division of Nephrology, Department of Medicine, Thomas Jefferson University, Philadelphia, PA
,Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA
| | - Samuel S. Gidding
- Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA
,Division of Cardiology, Nemours Cardiac Center, A.I. DuPont Hospital for Children, Wilmington, DE
| | - Heather E. Price
- Division of Kidney Diseases, Ann & Robert H. Lurie Children’s Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, IL
,Developmental Biology Program, The Lurie Research Institute, Chicago, IL
| | - Scott W. Keith
- Division of Biostatistics, Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA
| | - Craig B. Langman
- Division of Kidney Diseases, Ann & Robert H. Lurie Children’s Hospital of Chicago, Feinberg School of Medicine, Northwestern University, Chicago, IL
,Developmental Biology Program, The Lurie Research Institute, Chicago, IL
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Abstract
The prevalence of osteoporosis and the incidence of age-related fragility fracture vary by ethnicity. There is greater than 10-fold variation in fracture probabilities between countries across the world. Mineral and bone metabolism are intimately interlinked, and both are known to exhibit patterns of daily variation, known as the diurnal rhythm (DR). Ethnic differences are described for Ca and P metabolism. The importance of these differences is described in detail between select ethnic groups, within the USA between African-Americans and White-Americans, between the Gambia and the UK and between China and the UK. Dietary Ca intake is higher in White-Americans compared with African-Americans, and is higher in White-British compared with Gambian and Chinese adults. Differences are observed also for plasma 25-hydroxy vitamin D, related to lifestyle differences, skin pigmentation and skin exposure to UVB-containing sunshine. Higher plasma 1,25-dihydroxy vitamin D and parathyroid hormone are observed in African-American compared with White-American adults. Plasma parathyroid hormone is also higher in Gambian adults and, in winter, in Chinese compared with White-British adults. There may be ethnic differences in the bone resorptive effects of parathyroid hormone, with a relative skeletal resistance to parathyroid hormone observed in some, but not all ethnic groups. Renal mineral excretion is also influenced by ethnicity; urinary Ca (uCa) and urinary P (uP) excretions are lower in African-Americans compared with White-Americans, and in Gambians compared with their White-British counterparts. Little is known about ethnic differences in the DR of Ca and P metabolism, but differences may be expected due to known differences in lifestyle factors, such as dietary intake and sleep/wake pattern. The ethnic-specific DR of Ca and P metabolism may influence the net balance of Ca and P conservation and bone remodelling. These ethnic differences in Ca, P and the bone metabolism may be important factors in the variation in skeletal health.
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Affiliation(s)
- J. Redmond
- Elsie Widdowson Laboratory, Medical Research Council Human Nutrition Research, Cambridge CB1 9NL, UK
| | | | - B. Zhou
- Department of Public health, Shenyang Medical College, 146 Huanghe North Street, Shenyang 110034, People's Republic of China
| | - A. Prentice
- Elsie Widdowson Laboratory, Medical Research Council Human Nutrition Research, Cambridge CB1 9NL, UK
- Medical Research Council Keneba, The Gambia
| | - I. Schoenmakers
- Elsie Widdowson Laboratory, Medical Research Council Human Nutrition Research, Cambridge CB1 9NL, UK
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Ethnic differences in bone and mineral metabolism in healthy people and patients with CKD. Kidney Int 2013; 85:1283-9. [PMID: 24352156 DOI: 10.1038/ki.2013.443] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 08/07/2013] [Accepted: 08/15/2013] [Indexed: 12/24/2022]
Abstract
Several studies have shown racial differences in the regulation of mineral metabolism, in the acquisition of bone mass and structure of individuals. In this review, we examine ethnic differences in bone and mineral metabolism in normal individuals and in patients with chronic kidney disease. Black individuals have lower urinary excretion and increased intestinal calcium absorption, reduced levels of 25(OH)D, and high levels of 1.25(OH)2D and parathyroid hormone (PTH). Body phosphorus concentration is higher and the levels of FGF-23 are lower than in whites. Mineral density and bone architecture are better in black individuals. These differences translate into advantages for blacks who have stronger bones, less risk of fractures, and less cardiovascular calcification. In the United States of America, the prevalence of kidney disease is similar in different ethnic groups. However, black individuals progress more quickly to advanced stages of kidney disease than whites. This faster progression does not translate into increased mortality, higher in whites, especially in the first year of dialysis. Some ethnicity-related variations in mineral metabolism persist when individuals develop CKD. Therefore, black patients have lower serum calcium concentrations, less hyperphosphatemia, low levels of 25(OH)D, higher levels of PTH, and low levels of FGF-23 compared with white patients. Bone biopsy studies show that blacks have greater bone volume. The rate of fractures and cardiovascular diseases are also less frequent. Further studies are required to better understand the cellular and molecular bases of these racial differences in bone mineral metabolism and thus better treat patients.
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24
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Freedman BI, Divers J, Palmer ND. Population ancestry and genetic risk for diabetes and kidney, cardiovascular, and bone disease: modifiable environmental factors may produce the cures. Am J Kidney Dis 2013; 62:1165-75. [PMID: 23896482 PMCID: PMC3840048 DOI: 10.1053/j.ajkd.2013.05.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 05/24/2013] [Indexed: 12/22/2022]
Abstract
Variable rates of disease observed between members of different continental population groups may be mediated by inherited factors, environmental exposures, or their combination. This article provides evidence in support of differential allele frequency distributions that underlie the higher rates of nondiabetic kidney disease in the focal segmental glomerulosclerosis spectrum of disease and lower rates of coronary artery calcified atherosclerotic plaque and osteoporosis in populations of African ancestry. With recognition that these and other common complex diseases are affected by biological factors comes the realization that targeted manipulation of environmental exposures and pharmacologic treatments will have different effects based on genotype. The present era of precision medicine will couple one's genetic makeup with specific therapies to reduce rates of disease based on the presence of disease-specific alleles.
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Affiliation(s)
- Barry I Freedman
- Department of Internal Medicine-Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC; Center for Human Genomics and Personalized Medicine Research, Wake Forest School of Medicine, Winston-Salem, NC.
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Gravesen E, Hofman-Bang J, Lewin E, Olgaard K. Ergocalciferol treatment and aspects of mineral homeostasis in patients with chronic kidney disease stage 4-5. Scand J Clin Lab Invest 2013; 73:107-16. [PMID: 23281842 DOI: 10.3109/00365513.2012.744464] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Focus on non-classical effects and possible less side effects of treatment with nutritional vitamin D, raises the expectation of possible benefits from treating chronic kidney disease (CKD) patients with ergocalciferol (vitamin D2). Treatment with 1,25(OH)2 vitamin D (calcitriol) induces elevated fibroblast growth factor 23 (FGF23), while epidemiological studies have found positive effects of nutritional and 25(OH)vitamin D on mortality in CKD. Disturbed mineral homeostasis in CKD is correlated to adverse outcome and cardiovascular mortality. The objective was to examine the possible effects of treatment with high doses of ergocalciferol on parameters of mineral homeostasis in predialysis CKD patients. METHODS A total of 43 adult patients with CKD stage 4-5, not receiving vitamin D supplementation, were studied, and allocated by simple randomization to either an intervention (n = 26) or a control group (n = 17). The intervention group received ergocalciferol, 50.000 IU/week for 6 weeks. Plasma FGF23, creatinine, parathyroid hormone (PTH), phosphate and ionized calcium were obtained at baseline and after the 6 weeks. RESULTS The intervention group had a significant increase in 25(OH)D2 concentration from < 10 to 90 ± 4 nmol/L, while 1,25(OH)2D (62 ± 6 at baseline and 67 ± 6 pmol/L at 6 weeks) remained stable. No changes were seen in the circulating vitamin D concentrations in the control group. After the 6 weeks of treatment no significant changes were seen in concentration of creatinine, phosphate, ionized calcium, PTH and FGF23 remained stable. CONCLUSION No harmful effects of short-term treatment with high-dose ergocalciferol were observed on markers of mineral homeostasis and FGF23 in CKD patients stage 4-5.
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Affiliation(s)
- Eva Gravesen
- University of Copenhagen, Nephrological Department P, Rigshospitalet, Copenhagen, Denmark
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Isakova T. Racial differences in parathyroid hormone levels in CKD. Nephrol Dial Transplant 2012; 27:2616-7. [PMID: 22802577 DOI: 10.1093/ndt/gfs173] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Tamara Isakova
- Division of Nephrology and Hypertension, Department of Medicine, University of Miami, Miller School of Medicine, Miami, FL, USA.
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27
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Freedman BI, Register TC. Effect of race and genetics on vitamin D metabolism, bone and vascular health. Nat Rev Nephrol 2012; 8:459-66. [PMID: 22688752 PMCID: PMC10032380 DOI: 10.1038/nrneph.2012.112] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The pathophysiology of chronic kidney disease-mineral and bone disorder accounts for an inverse relationship between bone mineralization and vascular calcification in progressive nephropathy. Inverse associations between bone mineral density (BMD) and calcified atherosclerotic plaque are also observed in individuals of European and African ancestry without nephropathy, suggesting a mechanistic link between these processes that is independent of kidney disease. Despite lower dietary calcium intake and serum 25-hydroxyvitamin D (25(OH)D) concentrations, African Americans have higher BMD and develop osteoporosis less frequently than do European Americans. Moreover, despite having more risk factors for cardiovascular disease, African Americans have a lower incidence and severity of calcified atherosclerotic plaque formation than do European Americans. Strikingly, evidence is now revealing that serum 25(OH)D and/or 1,25 dihydroxyvitamin D levels associate positively with atherosclerosis but negatively with BMD in African Americans; by contrast, vitamin D levels associate negatively with atherosclerosis and positively with BMD in individuals of European ancestry. Biologic phenomena, therefore, seem to contribute to population-specific differences in vitamin D metabolism, bone and vascular health. Genetic and mechanistic approaches used to explore these differences should further our understanding of bone-blood vessel relationships and explain how African ancestry protects from osteoporosis and calcified atherosclerotic plaque, provided that access of African Americans to health care is equivalent to individuals of European ethnic origin. Ultimately, in our opinion, a new mechanistic understanding of the relationships between bone mineralization and vascular calcification will produce novel approaches for disease prevention in aging populations.
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Affiliation(s)
- Barry I Freedman
- Department of Internal Medicine, Section on Nephrology, Wake Forest School of Medicine, Winston-Salem, NC 27157-1053, USA.
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28
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Paik JM, Farwell WR, Taylor EN. Demographic, dietary, and serum factors and parathyroid hormone in the National Health and Nutrition Examination Survey. Osteoporos Int 2012; 23:1727-36. [PMID: 21932115 PMCID: PMC3741045 DOI: 10.1007/s00198-011-1776-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 08/23/2011] [Indexed: 01/05/2023]
Abstract
UNLABELLED Many determinants of parathyroid hormone (PTH) are unknown. In the National Health and Nutrition Examination Survey (NHANES), numerous factors not classically associated with calcium-phosphorus homeostasis, such as uric acid and smoking, are independently associated with PTH in adults without chronic kidney disease. Associations between serum phosphorus and PTH may vary by race. INTRODUCTION Although PTH may be an important biomarker for osteoporosis and cardiovascular disease, many determinants of PTH are unknown. We investigated associations between demographic, dietary, and serum factors and PTH level. METHODS We studied 4,026 white, 1,792 black, and 1,834 Mexican-American adult participants without chronic kidney disease from the 2003-2004 and 2005-2006 NHANES. RESULTS The mean serum PTH level was 38.3 pg/ml for whites, 42.6 pg/ml for blacks, and 41.3 pg/ml for Mexican-Americans. After adjusting for diet, body mass index, serum levels of calcium, phosphorus, 25-hydroxyvitamin D, creatinine, and other factors, smokers compared to non-smokers had lower PTH, ranging from -4.2 pg/ml (95% confidence interval (CI) -7.3 to -1.1) in Mexican-Americans to -6.1 pg/ml (95% CI -8.7 to -3.5) in blacks. After multivariate adjustment, PTH was higher in females compared to males, ranging from 1.1 pg/ml (95% CI -1.2 to 3.4) in Mexican-Americans to 4.5 pg/ml (95% CI 1.9 to 7.0) in blacks, and in older (>60 years) compared to younger participants (<30 years), ranging from 3.7 pg/ml (95% CI 1.3 to 6.1) in Mexican-Americans to 8.0 pg/ml (95% CI 5.4 to 10.7) in blacks. Higher uric acid was associated with higher PTH. In whites only, lower serum phosphorus and lower serum retinol were associated with higher PTH. CONCLUSIONS Numerous factors not classically associated with calcium-phosphorus homeostasis are independently associated with PTH and should be considered in future studies of PTH and chronic disease. Additional research is needed to elucidate mechanisms underlying identified associations with PTH and to explore possible racial differences in phosphorus handling.
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Affiliation(s)
- J M Paik
- Renal Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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29
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Gutiérrez OM, Smith KT, Barchi-Chung A, Patel NM, Isakova T, Wolf M. (1-34) Parathyroid hormone infusion acutely lowers fibroblast growth factor 23 concentrations in adult volunteers. Clin J Am Soc Nephrol 2012; 7:139-45. [PMID: 22246283 DOI: 10.2215/cjn.06240611] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND AND OBJECTIVES Fibroblast growth factor 23 (FGF23) regulates phosphorus and vitamin D metabolism. Parathyroid hormone (PTH) infusion for 24 hours stimulated FGF23 secretion in healthy volunteers. The extent to which this was due to a direct stimulatory effect of PTH versus an indirect effect of increasing 1,25-dihydroxyvitamin D [1,25(OH)(2)D] levels was unclear. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Changes in FGF23 in 26 adults undergoing 6-hour (1-34) PTH infusion were examined, focusing particularly on the effects of PTH on FGF23 in the early period of infusion before sustained increases in 1,25(OH)(2)D. RESULTS FGF23 levels declined in parallel with serum phosphate during infusion (P<0.05 for both), with both analytes decreasing within the first hour and reaching their respective nadirs at 6 hours. These changes were observed despite no change in 1,25(OH)(2)D levels during the first hour and a significant increase in 1,25(OH)(2)D from baseline after 6 hours (P<0.001). There were no differences in these responses by race. However, modest racial differences in the phosphaturic response to (1-34) PTH were observed (P=0.04 for interaction), with a higher rate of increase in fractional phosphate excretion in blacks than in whites. CONCLUSIONS During short-term (1-34) PTH infusion, FGF23 levels decreased in parallel with serum phosphate levels and despite significant increases in 1,25(OH)(2)D. When coupled with the results of prior longer-term infusion studies, these findings suggest that acute increases in PTH initially act to suppress FGF23 secretion, perhaps to mitigate urinary phosphate losses, before the stimulatory effect of 1,25(OH)(2)D on FGF23 eventually begins to predominate.
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Affiliation(s)
- Orlando M Gutiérrez
- Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, USA.
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30
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Ennis J, Worcester E, Coe F. Contribution of calcium, phosphorus and 25-hydroxyvitamin D to the excessive severity of secondary hyperparathyroidism in African-Americans with CKD. Nephrol Dial Transplant 2012; 27:2847-53. [DOI: 10.1093/ndt/gfs080] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Houston J, Smith K, Isakova T, Sowden N, Wolf M, Gutiérrez OM. Associations of dietary phosphorus intake, urinary phosphate excretion, and fibroblast growth factor 23 with vascular stiffness in chronic kidney disease. J Ren Nutr 2012; 23:12-20. [PMID: 22406119 DOI: 10.1053/j.jrn.2011.12.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Revised: 12/22/2011] [Accepted: 12/25/2011] [Indexed: 11/11/2022] Open
Abstract
OBJECTIVE Elevated serum phosphate concentrations are established risk factors for cardiovascular disease and mortality in chronic kidney disease (CKD). Independent associations of other indices of phosphorus metabolism, such as phosphorus intake, urinary phosphate excretion, or hormones that regulate these systems, like fibroblast growth factor 23 (FGF23), with markers of cardiovascular disease in CKD, have been studied in less detail. DESIGN Cross-sectional study. PARTICIPANTS Seventy-four adult CKD patients with mean creatinine clearance of 51 ± 19 mL/minute. OUTCOME Augmentation index (AI)--a surrogate marker of arterial stiffness. RESULTS Although serum phosphate varied little across quartiles of creatinine clearance, average daily phosphorus intake and 24-hour urinary phosphate excretion decreased from highest to lowest quartile (by 31% and 60%, respectively, P for trend <.05). FGF23 was associated with serum phosphate (r = 0.24, P = .03) and creatinine clearance (r = -0.4, P = .001), but not with dietary phosphorus or 24-hour urinary phosphate excretion (P > .05 for both). Older age, higher systolic blood pressure, female gender, and black race were independently associated with increased AI. In contrast, there were no associations of serum phosphate, dietary phosphorus intake, urinary phosphate excretion, or FGF23 with AI in multivariate-adjusted models. CONCLUSIONS In this sample of patients with CKD, established risk factors for arterial stiffness, but not mediators of phosphorus metabolism, were associated with increased AI. In addition, there were no significant associations between FGF23 and dietary phosphorus or urinary phosphate excretion. Future studies are needed to determine the main factors associated with elevations in FGF23 in CKD and to further assess the association of disordered phosphorus metabolism with subclinical markers of vascular disease.
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Affiliation(s)
- Jessica Houston
- Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, USA
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Pennick M, Poole L, Dennis K, Smyth M. Lanthanum carbonate reduces urine phosphorus excretion: evidence of high-capacity phosphate binding. Ren Fail 2012; 34:263-70. [PMID: 22250993 PMCID: PMC3296516 DOI: 10.3109/0886022x.2011.649657] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 11/03/2011] [Accepted: 12/09/2011] [Indexed: 11/13/2022] Open
Abstract
The effectiveness of phosphate binders can be assessed by evaluating urinary phosphorus excretion in healthy volunteers, which indicates the ability of the phosphate binder to reduce gastrointestinal phosphate absorption. Healthy volunteers were enrolled into one of five separate randomized trials; four were open label and one double blind. Following a screening period of ≤28 days, participants received differing tablets containing lanthanum carbonate [LC, 3000 mg/day of elemental lanthanum (in one study other doses were also used)]. Participants received a standardized phosphate diet and remained in the relevant study center throughout the duration of each treatment period. The end point in all studies was the reduction in urinary phosphorus excretion. Reductions in mean 24-h urinary phosphorus excretion in volunteers receiving a lanthanum dose of 3000 mg/day were between 236 and 468 mg/day over the five separate studies. These data in healthy volunteers can be used to estimate the amount of reduction of dietary phosphate absorption by LC. The reduction in 24-h urinary phosphorus excretion per tablet was compared with published data on other phosphate binders. Although there are limitations, evidence suggests that LC is a very effective phosphate binder in terms of binding per tablet.
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Affiliation(s)
| | - Lynne Poole
- Shire Pharmaceuticals Group Plc, Basingstoke, UK
| | - Kerry Dennis
- Shire Pharmaceuticals Group Plc, Basingstoke, UK
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Stubbs JR, He N, Idiculla A, Gillihan R, Liu S, David V, Hong Y, Quarles LD. Longitudinal evaluation of FGF23 changes and mineral metabolism abnormalities in a mouse model of chronic kidney disease. J Bone Miner Res 2012; 27:38-46. [PMID: 22031097 PMCID: PMC3439562 DOI: 10.1002/jbmr.516] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 08/23/2011] [Accepted: 09/07/2011] [Indexed: 12/11/2022]
Abstract
Fibroblast growth factor 23 (FGF23) is a phosphaturic and vitamin D-regulatory hormone of putative bone origin that is elevated in patients with chronic kidney disease (CKD). The mechanisms responsible for elevations of FGF23 and its role in the pathogenesis of chronic kidney disease-mineral bone disorder (CKD-MBD) remain uncertain. We investigated the association between FGF23 serum levels and kidney disease progression, as well as the phenotypic features of CKD-MBD in a Col4a3 null mouse model of human autosomal-recessive Alport syndrome. These mice exhibited progressive renal failure, declining 1,25(OH)(2)D levels, increments in parathyroid hormone (PTH) and FGF23, late-onset hypocalcemia and hyperphosphatemia, high-turnover bone disease, and increased mortality. Serum levels of FGF23 increased in the earliest stages of renal damage, before elevations in blood urea nitrogen (BUN) and creatinine. FGF23 gene transcription in bone, however, did not increase until late-stage kidney disease, when serum FGF23 levels were exponentially elevated. Further evaluation of bone revealed trabecular osteocytes to be the primary cell source for FGF23 production in late-stage disease. Changes in FGF23 mirrored the rise in serum PTH and the decline in circulating 1,25(OH)(2)D. The rise in PTH and FGF23 in Col4a3 null mice coincided with an increase in the urinary fractional excretion of phosphorus and a progressive decline in sodium-phosphate cotransporter gene expression in the kidney. Our findings suggest elevations of FGF23 in CKD to be an early marker of renal injury that increases before BUN and serum creatinine. An increased production of FGF23 by bone may not be responsible for early increments in FGF23 in CKD but does appear to contribute to FGF23 levels in late-stage disease. Elevations in FGF23 and PTH coincide with an increase in urinary phosphate excretion that likely prevents the early onset of hyperphosphatemia in the face of increased bone turnover and a progressive decline in functional renal mass.
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Affiliation(s)
- Jason R Stubbs
- The Kidney Institute, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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Chang PC, Saha S, Gomes AM, Padiyar A, Bodziak KA, Poggio ED, Hricik DE, Augustine JJ. Donor phosphorus levels and recipient outcomes in living-donor kidney transplantation. Clin J Am Soc Nephrol 2011; 6:1179-84. [PMID: 21310821 DOI: 10.2215/cjn.03220410] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND AND OBJECTIVES In living-donor kidney transplantation, various donor factors, including gender, age, and baseline kidney function, predict allograft function and recipient outcomes after transplantation. Because higher phosphorus is predictive of vascular injury in healthy adults, the effect of donor phosphorus levels on recipient renal function after transplantation was investigated. DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS Phosphorus levels in 241 living donors were analyzed from a 7-year period, and recipient renal function and acute rejection at 1 year posttransplantation were examined controlling for other influencing factors, including multiple donor variables, HLA matching, and acute rejection. RESULTS Female and African-American donors had significantly higher phosphorus levels predonation. By multivariable analysis, higher donor phosphorus correlated with higher recipient serum creatinine (slope=0.087, 95% confidence interval [CI]: 0.004 to 0.169, P=0.041) and lower recipient estimated GFR (slope=-4.321, 95% CI: -8.165 to -0.476, P=0.028) at 12 months. Higher donor phosphorus also displayed an independent correlation with biopsy-proven acute rejection and delayed or slow graft function after transplantation. CONCLUSIONS In a cohort of living kidney donors, higher donor phosphorus correlated with female gender and African-American ethnicity and was an independent risk factor for early allograft dysfunction after living-donor kidney transplantation.
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Affiliation(s)
- Peter C Chang
- Department of Medicine, Oregon Health and Science University, Portland, Oregon, USA
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Powe CE, Seely EW, Rana S, Bhan I, Ecker J, Karumanchi SA, Thadhani R. First trimester vitamin D, vitamin D binding protein, and subsequent preeclampsia. Hypertension 2010; 56:758-63. [PMID: 20733087 DOI: 10.1161/hypertensionaha.110.158238] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Previous studies report an association between vitamin D deficiency and hypertension, including the pregnancy-specific disorder preeclampsia. Circulating vitamin D is almost entirely bound to vitamin D binding protein, which increases 2-fold during pregnancy and previous studies have not examined vitamin D binding protein or free vitamin D levels. We performed a nested case-control study within the Massachusetts General Hospital Obstetric Maternal Study, measuring first trimester total 25-hydroxyvitamin D (25[OH]D) and vitamin D binding protein and calculating free 25(OH)D levels. We compared these levels from pregnancies complicated by subsequent preeclampsia (cases, n=39) with those from normotensive pregnancies (controls, n=131). First trimester total 25(OH)D levels were similar in cases and controls (27.4±1.9 versus 28.8±0.80 ng/mL; P=0.435). Despite an association between higher first trimester blood pressures and subsequent preeclampsia, first trimester total 25(OH)D was not associated with first trimester systolic (r=0.11; P=0.16) or diastolic blood pressures (r=0.03; P=0.72). Although there was a trend toward increased risk of preeclampsia with 25(OH)D levels <15 ng/mL (odds ratio: 2.5 [95% CI: 0.89 to 6.90]), this was attenuated after adjustment for body mass index and other covariates (odds ratio: 1.35 [95% CI: 0.40 to 4.50]). First trimester vitamin D binding protein and free 25(OH)D levels were similar in cases and controls and were not associated with first trimester blood pressures. These data suggest that first trimester total and free 25(OH)D levels are not independently associated with first trimester blood pressure or subsequent preeclampsia.
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Affiliation(s)
- Camille E Powe
- Division of Nephrology, Massachusetts General Hospital and Harvard Medical School, Boston, Mass 02114, USA
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