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Chaturvedi S, Vijayakumar TS, Job V, Mahendri NV, Salusky I, Agarwal I. A Cross-sectional Study on Fibroblast Growth Factor 23 and Other Markers of Mineral Metabolism in Healthy Children in India. SAUDI JOURNAL OF KIDNEY DISEASES AND TRANSPLANTATION 2023; 34:147-153. [PMID: 38146724 DOI: 10.4103/1319-2442.391893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2023] Open
Abstract
Fibroblast growth factor 23 (FGF23) plays a significant role in phosphate homeostasis but data on children are limited. We aimed to detect FGF23 levels in 107 healthy children aged 6-16 years and evaluate its correlation with markers of phosphate and calcium metabolism, and the dietary intake of calcium, phosphate, and proteins. Height, weight, and Tanner stages were measured, and dietary intake was calculated. Biochemical analyses of hemoglobin, serum calcium, phosphate, creatinine, Vitamin D, and plasma parathyroid hormone (PTH) and FGF23 levels were performed, alongside their associations with FGF23. Of the children, 65.4% were males. Their mean body mass index was 15.79 ± 2.96 for males and 16.5 ± SD 2.72 for females. The mean Vitamin D and PTH levels were 29.7 ± 1.1 ng/mL and 29.2 ± 1.2 pg/mL, respectively. The mean FGF23 levels were 159 ± 15.2 reference units (RU)/mL. The mean FGF23 levels were significantly higher in females (209.3 ± 31 RU/mL) than in males (132.3 ± 15.1 RU/mL). All biochemical parameters were within the normal range. FGF23 correlated with age, weight, and height, but not Vitamin D, PTH, or dietary calcium and phosphate. FGF23 showed a negative correlation with hemoglobin levels (r = -0.23). Since most children had a nonvegetarian diet, the FGF23 levels were not assessed in vegetarians. These observations were attributed to the rural lifestyle favoring adequate exposure to sunlight and physical activity. The increased FGF23 levels in females, the trends in urban settings, and the levels in strictly vegetarian diets need further study.
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Affiliation(s)
| | | | - Victoria Job
- Department of Clinical Biochemistry, Christian Medical College, Vellore, India
| | - N V Mahendri
- Department of Dietary, Christian Medical College, Vellore, India
| | - Isidro Salusky
- Department of Pediatric Nephrology, David Geffen School of Medicine UCLA, CA, USA
| | - Indira Agarwal
- Department of Pediatrics, Christian Medical College, Vellore, India
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Vlok M, Snoddy AME, Ramesh N, Wheeler BJ, Standen VG, Arriaza BT. The role of dietary calcium in the etiology of childhood rickets in the past and the present. Am J Hum Biol 2023; 35:e23819. [PMID: 36251616 DOI: 10.1002/ajhb.23819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 09/06/2022] [Accepted: 09/27/2022] [Indexed: 11/11/2022] Open
Abstract
For more than two centuries, lack of sunlight has been understood to cause vitamin D deficiency and documented as a primary cause of rickets. As such, evidence of rickets in the archeological record has been used as a proxy for vitamin D status in past individuals and populations. In the last decade, a clinical global consensus has emerged wherein it is recognized that dietary calcium deficiency also plays a role in the manifestation of rickets and classic skeletal deformities may not form if dietary calcium is normal even if vitamin D is deficient. This disease is now clinically called "nutritional rickets" to reflect the fact that rickets can take calcium deficiency-predominant or vitamin D deficiency-predominant forms. However, there are currently no paleopathological studies wherein dietary calcium deficiency is critically considered a primary etiology of the disease. We review here the interplay of calcium, vitamin D, and phosphorous in bone homeostasis, examine the role of dietary calcium in human health, and critically explore the clinical literature on calcium deficiency-predominant rickets. Finally, we report a case of rickets from the late Formative Period (~2500-1500 years ago) of the Atacama Desert and argue the disease in this infant is likely an example of calcium deficiency-predominant rickets. We conclude that most archeological cases of rickets are the result of multiple micronutrient deficiencies that compound to manifest in macroscopic skeletal lesions. For clinicians, these factors are important for implementing best treatment practice, and for paleopathologists they are necessary for appropriate interpretation of health in past communities.
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Affiliation(s)
- Melandri Vlok
- Sydney Southeast Asia Centre, The University of Sydney, Camperdown, Australia.,Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Anne Marie E Snoddy
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Niranjan Ramesh
- Department of Anatomy, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Benjamin J Wheeler
- Department of Women and Children's Health, Otago Medical School, University of Otago, Dunedin, New Zealand
| | - Vivien G Standen
- Departamento de Antropología, Universidad de Tarapacá, Arica, Chile
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3
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Vaculik J, Wenchich L, Bobelyak M, Pavelka K, Stepan JJ. A decrease in serum 1,25(OH) 2D after elective hip replacement and during bone healing is associated with changes in serum iron and plasma FGF23. J Endocrinol Invest 2022; 45:1039-1044. [PMID: 35079976 DOI: 10.1007/s40618-022-01746-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 01/13/2022] [Indexed: 10/19/2022]
Abstract
OBJECTIVE Although calcitriol is essential for bone healing, its serum concentrations are low after hip surgery, and they continue to decline during bone healing. This study aimed to test the hypothesis of an association of changes in calcitriol production with the status of fibroblast growth factor 23 (FGF23) and iron deficiency after elective hip replacement for coxarthrosis. METHODS In this prospective study, we measured the biomarkers of 17 patients undergoing elective hip replacement on admission, on the first day after surgery, and at the regular check-up after 48 ± 8 days. The serum concentrations of 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, transferrin, ferritin, parathyroid hormone, intact plasma FGF23 (iFGF23) and C-terminal FGF23 (cFGF23) were determined. RESULTS In our patients who underwent elective hip replacement, significant correlations existed between the percent change in the conversion rate of 25(OH)D to 1,25(OH)2D, plasma intact to C-terminal FGF23 ratio, and serum iron. CONCLUSIONS The production of calcitriol is compromised after elective hip replacement surgery, leading to reduced levels of active vitamin D in the serum. Significant correlations between the percent change in the conversion rate of 25(OH)D to 1,25(OH)2D, plasma intact to C-terminal FGF23 ratio, and serum iron on the first day as well as 7 weeks after surgery could inspire future studies to determine whether and how calcitriol deficiency should be corrected, especially in fracture cases.
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Affiliation(s)
- J Vaculik
- Orthopedic Department, Bulovka Hospital, Prague, Czech Republic
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
- Orthopedic Department, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - L Wenchich
- Institute of Rheumatology, Prague, Czech Republic
| | - M Bobelyak
- Orthopedic Department, Bulovka Hospital, Prague, Czech Republic
- Third Faculty of Medicine, Charles University, Prague, Czech Republic
| | - K Pavelka
- Institute of Rheumatology, Prague, Czech Republic
- Department of Rheumatology, First Faculty of Medicine, Charles University, Prague, Czech Republic
| | - J J Stepan
- Institute of Rheumatology, Prague, Czech Republic.
- Department of Rheumatology, First Faculty of Medicine, Charles University, Prague, Czech Republic.
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Mogire RM, Muriuki JM, Morovat A, Mentzer AJ, Webb EL, Kimita W, Ndungu FM, Macharia AW, Cutland CL, Sirima SB, Diarra A, Tiono AB, Lule SA, Madhi SA, Prentice AM, Bejon P, Pettifor JM, Elliott AM, Adeyemo A, Williams TN, Atkinson SH. Vitamin D Deficiency and Its Association with Iron Deficiency in African Children. Nutrients 2022; 14:nu14071372. [PMID: 35405984 PMCID: PMC9002534 DOI: 10.3390/nu14071372] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 03/09/2022] [Accepted: 03/15/2022] [Indexed: 11/16/2022] Open
Abstract
Vitamin D regulates the master iron hormone hepcidin, and iron in turn alters vitamin D metabolism. Although vitamin D and iron deficiency are highly prevalent globally, little is known about their interactions in Africa. To evaluate associations between vitamin D and iron status we measured markers of iron status, inflammation, malaria parasitemia, and 25-hydroxyvitamin D (25(OH)D) concentrations in 4509 children aged 0.3 months to 8 years living in Kenya, Uganda, Burkina Faso, The Gambia, and South Africa. Prevalence of iron deficiency was 35.1%, and prevalence of vitamin D deficiency was 0.6% and 7.8% as defined by 25(OH)D concentrations of <30 nmol/L and <50 nmol/L, respectively. Children with 25(OH)D concentrations of <50 nmol/L had a 98% increased risk of iron deficiency (OR 1.98 [95% CI 1.52, 2.58]) compared to those with 25(OH)D concentrations >75 nmol/L. 25(OH)D concentrations variably influenced individual markers of iron status. Inflammation interacted with 25(OH)D concentrations to predict ferritin levels. The link between vitamin D and iron status should be considered in strategies to manage these nutrient deficiencies in African children.
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Affiliation(s)
- Reagan M. Mogire
- Centre for Geographic Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research Institute (KEMRI), P.O. Box 230, Kilifi 80108, Kenya; (J.M.M.); (W.K.); (F.M.N.); (A.W.M.); (P.B.); (T.N.W.)
- KEMRI-Wellcome Trust Research Programme-Accredited Research Centre, Open University, P.O. Box 230, Kilifi 80108, Kenya
- Correspondence: (R.M.M.); (S.H.A.); Tel.: +254-709-983274 (R.M.M.); +254-709-983000 (S.H.A.)
| | - John Muthii Muriuki
- Centre for Geographic Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research Institute (KEMRI), P.O. Box 230, Kilifi 80108, Kenya; (J.M.M.); (W.K.); (F.M.N.); (A.W.M.); (P.B.); (T.N.W.)
| | - Alireza Morovat
- Department of Clinical Biochemistry, Oxford University Hospitals, Oxford OX3 9DU, UK;
| | - Alexander J. Mentzer
- Wellcome Centre for Human Genetics, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7BN, UK;
- Li Ka Shing Centre for Health Information and Discovery, Big Data Institute, University of Oxford, Oxford OX3 7LF, UK
| | - Emily L. Webb
- Medical Research Council (MRC) International Statistics and Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; (E.L.W.); (S.A.L.)
| | - Wandia Kimita
- Centre for Geographic Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research Institute (KEMRI), P.O. Box 230, Kilifi 80108, Kenya; (J.M.M.); (W.K.); (F.M.N.); (A.W.M.); (P.B.); (T.N.W.)
| | - Francis M. Ndungu
- Centre for Geographic Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research Institute (KEMRI), P.O. Box 230, Kilifi 80108, Kenya; (J.M.M.); (W.K.); (F.M.N.); (A.W.M.); (P.B.); (T.N.W.)
| | - Alex W. Macharia
- Centre for Geographic Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research Institute (KEMRI), P.O. Box 230, Kilifi 80108, Kenya; (J.M.M.); (W.K.); (F.M.N.); (A.W.M.); (P.B.); (T.N.W.)
| | - Clare L. Cutland
- African Leadership in Vaccinology Expertise (Alive), Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa;
| | - Sodiomon B. Sirima
- Groupe de Recherche Action en Sante (GRAS), Ouagadougou 06 BP 10248, Burkina Faso; (S.B.S.); (A.D.); (A.B.T.)
| | - Amidou Diarra
- Groupe de Recherche Action en Sante (GRAS), Ouagadougou 06 BP 10248, Burkina Faso; (S.B.S.); (A.D.); (A.B.T.)
| | - Alfred B. Tiono
- Groupe de Recherche Action en Sante (GRAS), Ouagadougou 06 BP 10248, Burkina Faso; (S.B.S.); (A.D.); (A.B.T.)
| | - Swaib A. Lule
- Medical Research Council (MRC) International Statistics and Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK; (E.L.W.); (S.A.L.)
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit, Entebbe P.O. Box 49, Uganda;
| | - Shabir A. Madhi
- South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Private Bag 3, Johannesburg 2050, South Africa;
| | - Andrew M. Prentice
- MRC Unit The Gambia at London School of Hygiene and Tropical Medicine, Banjul P.O. Box 273, The Gambia;
| | - Philip Bejon
- Centre for Geographic Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research Institute (KEMRI), P.O. Box 230, Kilifi 80108, Kenya; (J.M.M.); (W.K.); (F.M.N.); (A.W.M.); (P.B.); (T.N.W.)
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7LG, UK
| | - John M. Pettifor
- South African Medical Research Council/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, University of the Witwatersrand, R68 Old Potchefstroom Road, Bertsham, Johannesburg 2050, South Africa;
| | - Alison M. Elliott
- Medical Research Council/Uganda Virus Research Institute and London School of Hygiene and Tropical Medicine Uganda Research Unit, Entebbe P.O. Box 49, Uganda;
- Department of Clinical Research, London School of Hygiene and Tropical Medicine, London WC1E 7HT, UK
| | - Adebowale Adeyemo
- Centre for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20891-5635, USA;
| | - Thomas N. Williams
- Centre for Geographic Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research Institute (KEMRI), P.O. Box 230, Kilifi 80108, Kenya; (J.M.M.); (W.K.); (F.M.N.); (A.W.M.); (P.B.); (T.N.W.)
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7LG, UK
- Institute of Global Health Innovation, Department of Surgery and Cancer, Imperial College, London SW7 2NA, UK
| | - Sarah H. Atkinson
- Centre for Geographic Medicine Research-Coast, KEMRI-Wellcome Trust Research Programme, Kenya Medical Research Institute (KEMRI), P.O. Box 230, Kilifi 80108, Kenya; (J.M.M.); (W.K.); (F.M.N.); (A.W.M.); (P.B.); (T.N.W.)
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford OX3 7LG, UK
- Department of Paediatrics, University of Oxford, Oxford OX3 9DU, UK
- Correspondence: (R.M.M.); (S.H.A.); Tel.: +254-709-983274 (R.M.M.); +254-709-983000 (S.H.A.)
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Stanczyk M, Chrul S, Wyka K, Tkaczyk M. Serum intact fibroblast growth factor 23 in healthy paediatric population. Open Med (Wars) 2021; 16:1022-1027. [PMID: 34258392 PMCID: PMC8262519 DOI: 10.1515/med-2021-0288] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 03/28/2021] [Accepted: 04/20/2021] [Indexed: 11/25/2022] Open
Abstract
Introduction It is believed that fibroblast growth factor 23 (FGF23) can become an early biomarker of chronic kidney disease progression. Data on FGF23 age dependency are inconsistent. We present the results of the cross-sectional study concerning FGF23 levels in healthy Polish children. Material and methods This study was conducted in 121 children aged 0–18 years. Kidney function and intact FGF23 levels in serum were assessed. Differences between age groups and according to gender were analysed. Results The difference in FGF23 between age groups and according to gender was statistically insignificant. In the youngest and the oldest group, a trend to higher FGF23 levels was observed. FGF23 level in girls tended to be higher than boys, apart from the age group between 1 and 4 years. There was a negative correlation between eGFR and FGF23 (r = −0.26, p < 0.05) – strong in girls (r = −0.38, p < 0.05), but not in boys. In each age group, we found no significant correlation between eGFR and FGF23. Conclusions Our study supports the evidence that the FGF23 level in paediatric population is not age or sex dependent. The results can serve as a reference point under clinical conditions and for other studies on the topic.
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Affiliation(s)
- Malgorzata Stanczyk
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Rzgowska 281/289, Lodz 93-338, Poland.,Department of Pediatrics, Preventive Cardiology and Immunology of Developmental Age, Medical University of Lodz, Poland
| | - Slawomir Chrul
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Lodz 93-338, Poland
| | - Krystyna Wyka
- Department of Pediatrics, Oncology and Hematology, Medical University of Lodz, Lodz, Poland
| | - Marcin Tkaczyk
- Department of Pediatrics, Immunology and Nephrology, Polish Mother's Memorial Hospital Research Institute, Lodz 93-338, Poland.,Department of Pediatrics, Preventive Cardiology and Immunology of Developmental Age, Medical University of Lodz, Poland
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Braithwaite VS, Mwangi MN, Jones KS, Demir AY, Prentice A, Prentice AM, Andang'o PEA, Verhoef H. Antenatal iron supplementation, FGF23, and bone metabolism in Kenyan women and their offspring: secondary analysis of a randomized controlled trial. Am J Clin Nutr 2021; 113:1104-1114. [PMID: 33675347 PMCID: PMC8106766 DOI: 10.1093/ajcn/nqaa417] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 12/10/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Fibroblast growth factor-23 (FGF23) regulates body phosphate homeostasis primarily by increasing phosphaturia. It also acts as a vitamin D-regulating hormone. Maternal iron deficiency is associated with perturbed expression and/or regulation of FGF23 and hence might be implicated in the pathogenesis of hypophosphatemia-driven rickets in their offspring. OBJECTIVES We aimed to determine the effect of antenatal oral iron supplementation on FGF23 concentration and maternal and infant markers of bone-mineral regulation. METHODS We performed a secondary analysis of a trial in which 470 rural Kenyan women with singleton pregnancies and hemoglobin concentrations ≥ 90 g/L were randomly allocated to daily, supervised supplementation with 60 mg elemental iron as ferrous fumarate or placebo from 13-23 weeks of gestation until 1 mo postpartum. As previously reported, iron supplementation improved iron status in mothers and neonates. For the present study, we reanalyzed all available plasma samples collected in mothers and neonates at birth, with primary outcomes being concentrations of FGF23, measured by 2 assays: 1 that detects intact hormone and C-terminal cleavage products (total-FGF23) and another that detects the intact hormone only (intact-FGF23). RESULTS Analysis was performed on 433 women (n = 216, iron group; n = 217, placebo group) and 414 neonates (n = 207, iron group; n = 207, placebo group). Antenatal iron supplementation reduced geometric mean total-FGF23 concentrations in mothers and neonates by 62.6% (95% CI: 53.0%, 70.3%) and 15.2% (95% CI: -0.3%, 28.4%, P = 0.06), respectively. In addition, it increased geometric mean neonatal intact-FGF23 concentrations by 21.6% (95% CI: 1.2%, 46.1%), increased geometric mean maternal hepcidin concentrations by 136.4% (95% CI: 86.1%, 200.3%), and decreased mean maternal 25-hydroxyvitamin D concentrations by 6.1 nmol/L (95% CI: -11.0, -1.2 nmol/L). CONCLUSIONS Analysis of this randomized trial confirms that iron supplementation can reverse elevated FGF23 production caused by iron deficiency in iron-deficient mothers and their neonates. Further investigations are warranted to assess to what extent iron supplementation can prevent FGF23-mediated hypophosphatemic rickets or osteomalacia.
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Affiliation(s)
| | - Martin N Mwangi
- Wageningen University, Division of Human Nutrition and Health, P.O. Box 17, 6700 AA Wageningen, The Netherlands,University of Malawi, College of Medicine, Training and Research Unit of Excellence, Private Bag 360, BT 3, Chichiri, Blantyre, Malawi
| | - Kerry S Jones
- National Institute for Health Research (NIHR) Biomedical Research Centre Nutritional Biomarker Laboratory, MRC Epidemiology Unit, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AH, United Kingdom
| | - Ayşe Y Demir
- Meander Medical Centre, Laboratory for Clinical Chemistry and Hematology, P.O. Box 1502, 3800 BM Amersfoort, The Netherlands
| | - Ann Prentice
- Medical Research Council (MRC) Nutrition and Bone Health Research Group, Clifford Allbutt Building, University of Cambridge, Cambridge Biomedical Campus, Cambridge, CB2 0AH, United Kingdom (formerly the MRC Elsie Widdowson Laboratory, 120 Fulbourn Road, Cambridge, CB1 9NL, United Kingdom),Medical Research Council (MRC) Unit The Gambia at London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, Banjul, The Gambia
| | - Andrew M Prentice
- Medical Research Council (MRC) Unit The Gambia at London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, Banjul, The Gambia
| | - Pauline E A Andang'o
- Maseno University, School of Public Health and Community Development, Maseno, Kenya
| | - Hans Verhoef
- Wageningen University, Division of Human Nutrition and Health, P.O. Box 17, 6700 AA Wageningen, The Netherlands,Wageningen University, Cell Biology and Immunology Group, P.O. Box 338, 6708 WD Wageningen, The Netherlands
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7
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Enlund-Cerullo M, Hauta-Alus H, Valkama S, Rosendahl J, Andersson S, Mäkitie O, Holmlund-Suila E. Fibroblast growth factor 23 concentrations and modifying factors in children from age 12 to 24 months. Bone 2020; 141:115629. [PMID: 32919110 DOI: 10.1016/j.bone.2020.115629] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 08/29/2020] [Accepted: 09/05/2020] [Indexed: 12/19/2022]
Abstract
BACKGROUND AND OBJECTIVES Fibroblast growth factor 23 (FGF23) participates in phosphate, calcium and vitamin D metabolism. In children these interactions and modifying factors are largely unknown. PARTICIPANTS AND METHODS This study evaluates temporal changes and modifiers of FGF23 concentrations from 12 to 24 months, in healthy children, participating in a randomized vitamin D intervention (VIDI). Participants received vitamin D3 of 10 or 30 μg/day from age 2 weeks to 24 months. At 12 and 24 months, growth measurements and venous blood samples were obtained for analyses of intact (iFGF23) and C-terminal FGF23 (cFGF23), 25-hydroxyvitamin D (25-OHD), calcium, phosphate, parathyroid hormone, iron and ferritin. Changes in FGF23 and modifying factors were examined by linear mixed models. RESULTS The study included 594 infants. Girls had higher iFGF23 than boys (p < 0.001 for both 12 and 24 months), cFGF23 did not differ between the sexes. Adjusted mean iFGF23 decreased from 41.4 to 38.1 pg/mL in boys (p < 0.001) and from 45.2 to 42.5 pg/mL in girls (p = 0.002). Adjusted mean cFGF23 decreased from 2.89 to 2.00 pmol/L in boys (p < 0.001) and from 2.92 to 1.93 pmol/L in girls (p < 0.001). Iron modified FGF23 in both sexes, associating positively with iFGF23 and inversely with cFGF23. In girls, 25-OHD modified iFGF23. In boys, season modified FGF23, possibly through seasonal differences in 25-OHD. Vitamin D intervention dose did not affect FGF23. CONCLUSIONS FGF23 decreases from 12 to 24 months. Girls have higher iFGF23 than boys, at both time points. Iron modifies FGF23 in both sexes.
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Affiliation(s)
- Maria Enlund-Cerullo
- Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Folkhälsan Research Center, Helsinki, Finland; Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Finland.
| | - Helena Hauta-Alus
- Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Finland
| | - Saara Valkama
- Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Finland
| | - Jenni Rosendahl
- Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Finland
| | - Sture Andersson
- Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Outi Mäkitie
- Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Folkhälsan Research Center, Helsinki, Finland; Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Finland; Center for Molecular Medicine, Karolinska Institutet, Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
| | - Elisa Holmlund-Suila
- Children's Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland; Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Finland
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Ahmed S, Goldberg GR, Raqib R, Roy SK, Haque S, Braithwaite VS, Pettifor JM, Prentice A. Aetiology of nutritional rickets in rural Bangladeshi children. Bone 2020; 136:115357. [PMID: 32276153 PMCID: PMC7262584 DOI: 10.1016/j.bone.2020.115357] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 04/01/2020] [Accepted: 04/03/2020] [Indexed: 01/26/2023]
Abstract
OBJECTIVES A high prevalence of rickets of unknown aetiology has been reported in Chakaria, Bangladesh. Classically, rickets is caused by vitamin D deficiency but increasing evidence from Africa and Asia points towards other nutritional deficiencies or excessive exposure to some metals. The aim of this study was to investigate the aetiology of rickets in rural Bangladeshi children. METHODS 64 cases with rickets-like deformities were recruited at first presentation together with age-sex-village matched controls. Data and sample acquisition included anthropometry, radiographs, fasted plasma and urinary samples, 24 h weighed dietary intake together with a 24 h urine collection, and 13C-breath tests to detect Helicobacter (H.) pylori infection. RESULTS One child had active rickets and frank hypovitaminosis D (F, n = 1) and one had deformities with radiological features of Blount disease (M, n = 1). The remaining cases were grouped into those with active rickets, defined as a radiographic Thacher score ≥1.5 (Group A, n = 24, 12M, 12F) and rickets-like bone deformities but not active rickets (Group B, n = 38, 28M, 10F). All children had a low dietary calcium intake, but this was lower in Group A than their controls (mean (SD): 156 (80) versus 323 (249) mg/day, p = 0.005). Plasma 25-hydroxyvitamin D (25OHD) was lower in Group A compared to controls; 63% of Group A and 8% of controls had a concentration <25 nmol/L (p ≤ 0.0001). There was, however, no evidence of differences in skin sunshine exposure. Group A had lower plasma calcium and phosphate and higher 1,25-dihydroxyvitamin D (1,25(OH)2D) and parathyroid hormone (PTH). 88% of Group A and 0% of controls had undetectable plasma intact fibroblast growth factor (iFGF23), with c-terminal FGF23 (cFGF23) concentrations in the normal range. Urinary phosphate and daily outputs of environmental metals relative to creatinine were higher and tubular maximal phosphate reabsorption per unit glomerular filtration rate (TmP/GFR) was lower in Group A compared to controls. Although less pronounced than Group A, Group B had higher alkaline phosphatase, 1,25(OH)2D and PTH concentrations than controls but similar calcium intake, TmP/GFR, iFGF23 and cFGF23 concentrations. Mean 25OHD concentrations were also similar to controls and there was no significant difference in the percentage <25 nmol/L (Group B: 13%, controls: 5%, p = 0.2) No group differences were seen in prevalence of anaemia, iron deficiency or H. pylori infection. CONCLUSION Nutritional rickets in this region is likely to be predominantly due to low calcium intake in the context of poor vitamin D status and exposure to environmental metals, but not H. pylori infection, anaemia or iron deficiency.
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Affiliation(s)
- Sonia Ahmed
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK; International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka 1000, Bangladesh.
| | - Gail R Goldberg
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK
| | - Rubhana Raqib
- International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka 1000, Bangladesh
| | - Swapan Kumar Roy
- International Centre for Diarrhoeal Disease Research, Bangladesh (ICDDR,B), Dhaka 1000, Bangladesh
| | - Shahidul Haque
- Social Assistance and Rehabilitation for the Physically Vulnerable (SARPV), Dhaka 1207, Bangladesh
| | - Vickie S Braithwaite
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK; MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Cambridge CB2 0SL, UK
| | - John M Pettifor
- SAMRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, University of the Witwatersrand, Johannesburg, South Africa
| | - Ann Prentice
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK
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9
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Sayehmiri K, Shohani M, Kalvandi G, Najafi R, Tavan H. Biochemical parameters of rickets in Iranian children: A systematic review and meta-analysis. JOURNAL OF RESEARCH IN MEDICAL SCIENCES 2019; 24:76. [PMID: 31523262 PMCID: PMC6734666 DOI: 10.4103/jrms.jrms_354_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 12/19/2018] [Accepted: 05/05/2019] [Indexed: 12/13/2022]
Abstract
Background: Many causes can lead to childhood rickets. We aimed to investigate the biochemical symptoms of childhood rickets with systematic review and meta-analysis. Materials and Methods: Seven articles published from 1975 to 2018 were recruited. The literature search was performed in the Scientific Information Database, Google Scholar, PubMed, and Elsevier databases using related keywords. For meta-analysis, the results of the studies were pooled using the random-effects model. The heterogeneity between the studies was checked using Q test and I2 index. Results: The total sample population consisted of 933 children with biochemical symptoms of rickets (133 participants per article). According to our findings, the mean serum levels of PO4, Ca, and alkaline phosphatase in children with rickets were 4.18 (95% confidence interval [CI]: 3.75–4.61, I2 = 98.3%, P < 0.001), 9.23 (95% CI: 8.78–9.68, I2 = 99.6%, P < 0.001), and 1.33 (95% CI: 1.23–1.44, I2 = 95.6%, P < 0.001), respectively. Conclusion: Characterizing the biochemical symptoms of rickets in children can help to early diagnose and prevent the disease in children. Furthermore, educating parents about biochemical symptoms can lead to early diagnosis and successful treatment of rickets in children.
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Affiliation(s)
- Kourosh Sayehmiri
- Professor of Biostatistics, School of Medicine, Psychosocial Injuries Research Center, Ilam University of Medical Sciences, Ilam, Iran
| | - Masoumeh Shohani
- Assistant Professor, PhD of Nursing, Department of Nursing, Faculty of Nursing and Midwifery, Ilam University of Medical Sciences, Ilam, Iran
| | - Gholamreza Kalvandi
- Associate Professor of Pediatrics Gastroenterology, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Reza Najafi
- Assistant Professor of Pediatric Endocrinology & Metabolism, School of Medicine, Ilam University of Medical Sciences, Ilam, Iran
| | - Hamed Tavan
- Faculty of Nursing and Midwifery, Student Research Committee, Ilam University of Medical Sciences, Ilam, Iran
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10
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Bär L, Stournaras C, Lang F, Föller M. Regulation of fibroblast growth factor 23 (FGF23) in health and disease. FEBS Lett 2019; 593:1879-1900. [PMID: 31199502 DOI: 10.1002/1873-3468.13494] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2019] [Revised: 03/26/2019] [Accepted: 03/27/2019] [Indexed: 12/19/2022]
Abstract
Fibroblast growth factor 23 (FGF23) is mainly produced in the bone and, upon secretion, forms a complex with a FGF receptor and coreceptor αKlotho. FGF23 can exert several endocrine functions, such as inhibiting renal phosphate reabsorption and 1,25-dihydroxyvitamin D3 production. Moreover, it has paracrine activities on several cell types, including neutrophils and hepatocytes. Klotho and Fgf23 deficiencies result in pathologies otherwise encountered in age-associated diseases, mainly as a result of hyperphosphataemia-dependent calcification. FGF23 levels are also perturbed in the plasma of patients with several disorders, including kidney or cardiovascular diseases. Here, we review mechanisms controlling FGF23 production and discuss how FGF23 regulation is perturbed in disease.
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Affiliation(s)
- Ludmilla Bär
- Institute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Christos Stournaras
- Institute of Biochemistry, University of Crete Medical School, Heraklion, Greece
| | - Florian Lang
- Institute of Physiology, University of Tübingen, Germany
| | - Michael Föller
- Institute of Physiology, University of Hohenheim, Stuttgart, Germany
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11
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Bharati J, Bhatia D, Khandelwal P, Gupta N, Sinha A, Khadgawat R, Hari P, Bagga A. C-Terminal Fibroblast Growth Factor-23 Levels in Non-Nutritional Hypophosphatemic Rickets. Indian J Pediatr 2019; 86:555-557. [PMID: 30835073 DOI: 10.1007/s12098-019-02909-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2018] [Accepted: 02/14/2019] [Indexed: 01/08/2023]
Abstract
Fibroblast growth factor-23 (FGF23) is central to phosphate homeostasis. The author examined if blood levels of FGF23 allow discrimination of classic hypophosphatemic rickets from other causes of non-nutritional rickets with hypophosphatemia. Forty-two children (median age: 102 mo) with non-nutritional rickets and hypophosphatemia were clinically classified as having distal renal tubular acidosis (RTA, n = 12), Fanconi syndrome (n = 8), classic hypophosphatemic rickets (n = 11), vitamin D dependent rickets (n = 7) and Dent disease (n = 4). Median blood FGF23 (measured by C-terminal ELISA) concentrations were similar in all groups (P = 0.24). These levels did not correlate with phosphate, tubular maximum for phosphate, calcium, 25-hydroxyvitamin D, creatinine, and parathormone levels. Patients with distal RTA showed variable degree of proximal tubular dysfunction that resolved following alkali supplements. Blood FGF23 levels did not satisfactorily differentiate classic hypophosphatemic rickets from other causes of hypophosphatemic rickets.
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Affiliation(s)
- Joyita Bharati
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Divya Bhatia
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Priyanka Khandelwal
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Nandita Gupta
- Department of Endocrinology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Aditi Sinha
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Rajesh Khadgawat
- Department of Endocrinology, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Pankaj Hari
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India
| | - Arvind Bagga
- Division of Nephrology, Department of Pediatrics, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, 110029, India.
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Abstract
Dysregulated iron homeostasis plays a central role in the development of anemia of chronic kidney disease (CKD) and is a major contributor toward resistance to treatment with erythropoiesis-stimulating agents. Understanding the underlying pathophysiology requires an in-depth understanding of normal iron physiology and regulation. Recent discoveries in the field of iron biology have greatly improved our understanding of the hormonal regulation of iron trafficking in human beings and how its alterations lead to the development of anemia of CKD. In addition, emerging evidence has suggested that iron homeostasis interacts with bone and mineral metabolism on multiple levels, opening up new avenues of investigation into the genesis of disordered iron metabolism in CKD. Building on recent advances in our understanding of normal iron physiology and abnormalities in iron homeostasis in CKD, this review characterizes how anemia related to disordered iron metabolism develops in the setting of CKD. In addition, this review explores our emerging recognition of the connections between iron homeostasis and mineral metabolism and their implications for the management of altered iron status and anemia of CKD.
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Affiliation(s)
- Bhupesh Panwar
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL.
| | - Orlando M Gutiérrez
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL; Department of Epidemiology, University of Alabama at Birmingham, Birmingham, AL
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13
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Abstract
Rickets is a bone disease associated with abnormal serum calcium and phosphate levels. The clinical presentation is heterogeneous and depends on the age of onset and pathogenesis but includes bowing deformities of the legs, short stature and widening of joints. The disorder can be caused by nutritional deficiencies or genetic defects. Mutations in genes encoding proteins involved in vitamin D metabolism or action, fibroblast growth factor 23 (FGF23) production or degradation, renal phosphate handling or bone mineralization have been identified. The prevalence of nutritional rickets has substantially declined compared with the prevalence 200 years ago, but the condition has been re-emerging even in some well-resourced countries; prematurely born infants or breastfed infants who have dark skin types are particularly at risk. Diagnosis is usually established by medical history, physical examination, biochemical tests and radiography. Prevention is possible only for nutritional rickets and includes supplementation or food fortification with calcium and vitamin D either alone or in combination with sunlight exposure. Treatment of typical nutritional rickets includes calcium and/or vitamin D supplementation, although instances infrequently occur in which phosphate repletion may be necessary. Management of heritable types of rickets associated with defects in vitamin D metabolism or activation involves the administration of vitamin D metabolites. Oral phosphate supplementation is usually indicated for FGF23-independent phosphopenic rickets, whereas the conventional treatment of FGF23-dependent types of rickets includes a combination of phosphate and activated vitamin D; an anti-FGF23 antibody has shown promising results and is under further study.
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14
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Holmlund-Suila E, Enlund-Cerullo M, Valkama S, Hauta-Alus H, Rosendahl J, Helve O, Hytinantti T, Viljakainen H, Andersson S, Mäkitie O. Sex and Iron Modify Fibroblast Growth Factor 23 Concentration in 1-Year-Old Children. J Clin Endocrinol Metab 2017; 102:4526-4533. [PMID: 29029193 DOI: 10.1210/jc.2017-01211] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/29/2017] [Indexed: 01/29/2023]
Abstract
CONTEXT Fibroblast growth factor 23 (FGF23) plays an important role in phosphate homeostasis, but its regulation is inadequately characterized. OBJECTIVE To examine FGF23 regulators, especially sex and iron status, in early childhood. DESIGN A cross-sectional study involving 1-year-old children. SETTING AND PARTICIPANTS Healthy term infants with a birth weight appropriate for gestational age were recruited to an ongoing vitamin D trial at Kätilöopisto Maternity Hospital, Helsinki, Finland. At 12-month follow-up visits, serum FGF23, 25-hydroxyvitamin D (25OHD), phosphate, ionized calcium, parathyroid hormone, and iron status were measured. All 721 children (51% girls) with complete data were included. MAIN OUTCOME MEASURES Intact and C-terminal FGF23 concentrations and iron status at 1 year of age. RESULTS Intact FGF23 was greater in girls than in boys [median, 44.4 pg/mL; interquartile range (IQR), 36.8 to 51.9; median, 40.9 pg/mL; IQR, 34.5 to 49.0, respectively; P < 0.001]. C-terminal FGF23 was similar in boys and girls (median, 2.8 pmol/L; IQR, 2.1 to 3.7; median, 2.9 pmol/L; IQR, 2.2 to 3.7, respectively; P = 0.393). The iron concentration was positively associated with intact FGF23 and was the strongest modifier of intact FGF23 (regression coefficient, 0.498; 95% confidence interval, 0.333 to 0.663; P < 0.001) with ferritin, season, ionized calcium, 25OHD, and sex as other covariates. The association between iron and C-terminal FGF23 was inversely related (regression coefficient, -0.072; 95% confidence interval, -0.092 to -0.051; P < 0.001). CONCLUSIONS At 1 year of age, FGF23 status was different in girls and boys, with intact FGF23 concentrations higher in girls. Iron modified FGF23 concentrations, with intact FGF23 higher and C-terminal lower, in those with greater iron concentrations.
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Affiliation(s)
- Elisa Holmlund-Suila
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
| | - Maria Enlund-Cerullo
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
- Folkhälsan Research Center, Finland
| | - Saara Valkama
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
| | - Helena Hauta-Alus
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
| | - Jenni Rosendahl
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
| | - Otto Helve
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
| | - Timo Hytinantti
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
| | - Heli Viljakainen
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
- Folkhälsan Research Center, Finland
| | - Sture Andersson
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
| | - Outi Mäkitie
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Finland
- Folkhälsan Research Center, Finland
- Center for Molecular Medicine, Karolinska Institutet, and Clinical Genetics, Karolinska University Hospital, Sweden
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15
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Kosk D, Kramer H, Luke A, Camacho P, Bovet P, Rhule JP, Forrester T, Wolf M, Sempos C, Melamed ML, Dugas LR, Cooper R, Durazo-Arvizu R. Dietary factors and fibroblast growth factor-23 levels in young adults with African ancestry. J Bone Miner Metab 2017; 35:666-674. [PMID: 27942978 PMCID: PMC5711483 DOI: 10.1007/s00774-016-0804-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/31/2016] [Indexed: 11/30/2022]
Abstract
Fibroblast growth factor-23 (FGF23), a phosphaturic hormone secreted mainly by osteocytes, maintains serum phosphate levels within a tight range by promoting phosphaturia. Previous studies have mainly focused on the link between FGF23 levels and dietary intake of phosphate, but other dietary factors may also influence FGF23 levels. This cross-sectional study pooled three populations of young adults with African ancestry (452 in Chicago, IL, USA; 477 in Victoria, Seychelles; and 482 in Kumasi, Ghana) with estimated glomerular filtration rate >80 ml/min/1.73 m2 to examine the association of dietary factors based on two 24-h recalls with FGF23 levels measured using a C-terminal assay. Linear regression was used to examine the association between log-transformed FGF23 levels and quartiles of calorie-adjusted dietary factors with adjustment for covariates. In the pooled sample of 1411 study participants, the mean age was 35.2 (6.2) years and 45.3% were male. Median plasma C-terminal FGF23 values in relative units (RU)/ml were 59.5 [interquartile range (IQR) 44.1, 85.3] in the USA, 43.2 (IQR 33.1, 57.9) in Seychelles, and 34.0 (IQR 25.2, 50.4) in Ghana. With adjustment for covariates, increasing quartiles of calcium and animal protein and decreasing quartiles of vegetable protein, fiber, and magnesium intake were associated with significantly higher FGF23 levels compared to the lowest quartile. After further adjustment for dietary factors, significant trends in FGF23 levels were noted only for quartiles of calcium, fiber, and magnesium intake (P < 0.001). Dietary factors other than phosphate are associated with FGF23 levels in young adults.
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Affiliation(s)
- Dominique Kosk
- Department of Public Health Sciences, Loyola University Chicago, 2160 First Avenue, Maywood, IL, 60153, USA
| | - Holly Kramer
- Department of Public Health Sciences, Loyola University Chicago, 2160 First Avenue, Maywood, IL, 60153, USA.
- Division of Nephrology and Hypertension, Department of Public Health Sciences and Medicine, Loyola University Chicago, Maywood, IL, USA.
| | - Amy Luke
- Department of Public Health Sciences, Loyola University Chicago, 2160 First Avenue, Maywood, IL, 60153, USA
| | - Pauline Camacho
- Division of Endocrinology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, USA
| | - Pascal Bovet
- Institute of Social and Preventive Medicine, Lausanne University Hospital, Lausanne, Switzerland
- Ministry of Health, Victoria, Republic of Seychelles
| | - Jacob Plange Rhule
- Department of Physiology, School of Medical Sciences, Kwame Nkrumah University of Science and Technology, Kumasi, Ghana
| | - Terrence Forrester
- University of West Indies Solutions for Developing Countries, University of the West Indies Mona, Kingston, Jamaica
| | - Myles Wolf
- Division of Nephrology and Hypertension, Department of Medicine, Center for Translational Metabolism and Health, Institute for Public Health and Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Chris Sempos
- National Institutes of Health Office of Dietary Supplements, Bethesda, MD, USA
| | - Michal L Melamed
- Department of Medicine and Epidemiology and Population Health, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA
| | - Lara R Dugas
- Department of Public Health Sciences, Loyola University Chicago, 2160 First Avenue, Maywood, IL, 60153, USA
| | - Richard Cooper
- Department of Public Health Sciences, Loyola University Chicago, 2160 First Avenue, Maywood, IL, 60153, USA
| | - Ramon Durazo-Arvizu
- Department of Public Health Sciences, Loyola University Chicago, 2160 First Avenue, Maywood, IL, 60153, USA
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16
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Honda H, Michihata T, Shishido K, Takahashi K, Takahashi G, Hosaka N, Ikeda M, Sanada D, Shibata T. High fibroblast growth factor 23 levels are associated with decreased ferritin levels and increased intravenous iron doses in hemodialysis patients. PLoS One 2017; 12:e0176984. [PMID: 28475601 PMCID: PMC5419608 DOI: 10.1371/journal.pone.0176984] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 04/20/2017] [Indexed: 11/23/2022] Open
Abstract
A recent study demonstrated the association between inflammation, iron metabolism and fibroblast growth factor (FGF) 23. The present clinical study aimed to assess associations between anemia, iron metabolism and FGF23 in hemodialysis (HD) patients. This prospective observational study examined a cohort of prevalent HD patients (n = 282). Blood samples were obtained before dialysis sessions to measure baseline levels of hemoglobin (Hb), transferrin saturation (TSAT), ferritin, albumin-adjusted calcium (Ca), phosphate (P), intact (i)-PTH, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, intact (i)-FGF23, high sensitive (hs)-CRP, and interleukin-6. After the baseline measurement, study patients were followed-up for 6 months. Biochemical measurements were subsequently performed at 1 (Hb), 2 (TSAT and ferritin) or 3 (Ca, P and hs-CRP) month intervals. Doses of ESAs and intravenous iron supplementation during the study period were recorded. i-FGF23 was positively correlated with Ca, P, i-PTH and inversely correlated with TSAT and ferritin. However, levels of Hb and hs-CRP and doses of ESAs during the study period did not differ among the i-FGF23 tertiles, with levels of ferritin and TSAT in the higher i-FGF23 tertile being consistently lower than in the middle to lower i-FGF23 tertiles. Multivariate repeated measures analysis indicated that the higher i-FGF23 tertile was independently associated with repeated measurements of ferritin, but not of TSAT. Doses of intravenous iron supplementation were significantly increased in the higher i-FGF23 tertile in multivariate models. In conclusion, high i-FGF23 levels may be associated with prolongation of low levels of ferritin, resulting in increased usages of iron supplementation in HD patients.
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Affiliation(s)
- Hirokazu Honda
- Showa University Koto Toyosu Hospital, Division of Nephrology, Department of Medicine, Tokyo, Japan
- Showa University, School of Medicine, Division of Nephrology, Department of Medicine, Tokyo, Japan
- * E-mail:
| | | | - Kanji Shishido
- Kawasaki Clinic, Department of Dialysis, Kawasaki, Japan
| | - Keiko Takahashi
- Division of Dialysis, Kitami Higashiyama Clinic, Tokyo, Japan
| | - Go Takahashi
- Showa University Northern Yokohama Hospital, Department of Internal Medicine, Yokohama, Japan
| | - Nozomu Hosaka
- Showa University Koto Toyosu Hospital, Division of Nephrology, Department of Medicine, Tokyo, Japan
- Showa University, School of Medicine, Division of Nephrology, Department of Medicine, Tokyo, Japan
| | - Misa Ikeda
- Showa University, School of Medicine, Division of Nephrology, Department of Medicine, Tokyo, Japan
| | - Daisuke Sanada
- Showa University, School of Medicine, Division of Nephrology, Department of Medicine, Tokyo, Japan
| | - Takanori Shibata
- Showa University Northern Yokohama Hospital, Department of Internal Medicine, Yokohama, Japan
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17
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Lewerin C, Ljunggren Ö, Nilsson-Ehle H, Karlsson MK, Herlitz H, Lorentzon M, Ohlsson C, Mellström D. Low serum iron is associated with high serum intact FGF23 in elderly men: The Swedish MrOS study. Bone 2017; 98:1-8. [PMID: 28212898 DOI: 10.1016/j.bone.2017.02.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 01/19/2017] [Accepted: 02/13/2017] [Indexed: 12/19/2022]
Abstract
BACKGROUND Fibroblast growth factor (FGF23) is a protein that is produced by osteoblasts and osteocytes. Increased serum levels of FGF23 have been associated with increased risks of osteoporotic fractures and cardiovascular disease, particularly in participants with poor renal function. Serum iron (Fe) has been suggested as a regulator of FGF23 homeostasis. OBJECTIVE To determine whether Fe and iron status are determinants of the levels of intact FGF23 (iFGF23) in elderly men. METHODS The MrOS study is a population-based study of elderly men (N=1010; mean age, 75.3years; range, 69-81years). The levels of Fe, transferrin saturation (TS), and ferritin were evaluated in relation to the serum concentrations of iFGF23 before and after adjustments for confounders. RESULTS TS <15% was found in 3.5% (34/977) of the participants, who had a higher median level iFGF23 compared with the remaining subjects (47.4μmol/L vs. 41.9μmol/L, p=0.008). The levels of iFGF23 correlated negatively (un-adjusted) with the levels of Fe (r=-0.17, p<0.001), TS (r=-0.16, p<0.001) and serum ferritin (r=-0.07, p=0.022). In addition, in participants with estimated glomerular filtration rate eGFRCystatin C>60mL/min, the levels of iFGF23 correlated (age-adjusted) negatively with the levels of Fe (r=-0.15, p<0.001) and TS (r=-0.17, p<0.001). The level of iFGF23 correlated positively (un-adjusted) with lumbar spine bone mineral density (BMD) (r=0.14, p<0.001), total body BMD (r=0.11, p=0.001), and total hip BMD (r=0.09, p=0.004). The corresponding correlations, when adjusted for age, weight, and height were: r=0.08, p=0.018; r=0.05, p=0.120; and r=0.02, p=0.624, respectively. No associations were found between BMD and the levels of Fe or TS. Multiple step-wise linear regression analyses [adjusting for age, body mass index (BMI), comorbidity index, cystatin C, C-reactive protein (hs-CRP), serum vitamin D 25-OH (25OHD), phosphate, calcium, parathyroid hormone (PTH), erythropoietin, hemoglobin, lumbar spine BMD, apolipoprotein B/A1 ratio] were performed in three separate models with Fe, TS or ferritin as potential explanatory variables. Fe and TS, but not ferritin, were independent predictors of iFGF23 level (standardized β-values: -0.10, p<0.001; -0.10, p<0.001; and -0.05, p=0.062, respectively). CONCLUSION Low levels of Fe in elderly men are associated with high levels of iFGF23, independently of markers of inflammation and renal function, suggesting an iron-related pathway for FGF23 regulation.
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Affiliation(s)
- Catharina Lewerin
- Section of Hematology and Coagulation, Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
| | - Östen Ljunggren
- Department of Medical Sciences, University of Uppsala, Uppsala, Sweden.
| | - Herman Nilsson-Ehle
- Section of Hematology and Coagulation, Department of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
| | - Magnus K Karlsson
- Clinical and Molecular Osteoporosis Research Unit, Department of Clinical Sciences and Orthopedics, Lund University, Malmö, Sweden.
| | - Hans Herlitz
- Department of Molecular and Clinical Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
| | - Mattias Lorentzon
- Center for Bone and Arthritis Research (CBAR), Departments of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden; Dept of Geriatric Medicine, Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
| | - Claes Ohlsson
- Center for Bone and Arthritis Research (CBAR), Departments of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
| | - Dan Mellström
- Center for Bone and Arthritis Research (CBAR), Departments of Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden; Dept of Geriatric Medicine, Internal Medicine, Institute of Medicine, Sahlgrenska Academy, University of Gothenburg, Sweden.
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18
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Creo AL, Thacher TD, Pettifor JM, Strand MA, Fischer PR. Nutritional rickets around the world: an update. Paediatr Int Child Health 2017; 37:84-98. [PMID: 27922335 DOI: 10.1080/20469047.2016.1248170] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Worldwide, nutritional rickets continues to be an evolving problem with several causes. This paper provides an updated literature review characterising the prevalence, aetiology, pathophysiology and treatment of nutritional rickets worldwide. A systematic review of articles on nutritional rickets from various geographical regions was undertaken. For each region, key information was extracted, including prevalence, cause of rickets specific to the region, methods of confirming the diagnosis and current treatment and preventive measures. Calcium deficiency continues to be a major cause of rickets in Africa and Asia. Vitamin D deficiency rickets is perhaps increasing in the Americas, Europe and parts of the Middle East. There continues to be a distinct presentation of calcium-predominant versus vitamin D predominant rickets, although there are overlapping features. More careful diagnosis of rickets and reporting of 25-OHD concentrations has improved accurate knowledge of rickets prevalence and better delineated the cause. Nutritional rickets continues to be an evolving and multi-factorial problem worldwide. It is on a spectrum, ranging from isolated vitamin D deficiency to isolated calcium deficiency. Specific areas which require emphasis include a consistent community approach to screening and diagnosis, vitamin D supplementation of infants and at-risk children, prevention of maternal vitamin D deficiency and the provision of calcium in areas with low calcium diets.
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Affiliation(s)
- Ana L Creo
- a Department of Pediatric and Adolescent Medicine , Mayo Clinic , Rochester , MN , USA
| | - Tom D Thacher
- b Department of Family Medicine , Mayo Clinic , Rochester , MN , USA
| | - John M Pettifor
- c Wits/SAMRC Developmental Pathways for Health Research Unit, Department of Paediatrics , University of the Witwatersrand , Johannesburg , South Africa
| | - Mark A Strand
- d Pharmacy Practice, Department of Public Health , North Dakota State University , Fargo , ND , USA
| | - Philip R Fischer
- a Department of Pediatric and Adolescent Medicine , Mayo Clinic , Rochester , MN , USA
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Holmlund-Suila E, Viljakainen H, Ljunggren Ö, Hytinantti T, Andersson S, Mäkitie O. Fibroblast Growth Factor 23 Concentrations Reflect Sex Differences in Mineral Metabolism and Growth in Early Infancy. Horm Res Paediatr 2017; 85:232-41. [PMID: 26943634 DOI: 10.1159/000443988] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 01/11/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The role of fibroblast growth factor 23 (FGF23) in the regulation of mineral homeostasis in early life is inadequately understood. We aimed to explore the effects of vitamin D supplementation on serum FGF23 and to elucidate longitudinal changes in FGF23, in addition to studying its association with mineral metabolism in early infancy. METHODS Altogether 113 healthy infants received vitamin D3 10, 30 or 40 µg/day from age 0.5 to 3.0 months. Cord blood at birth and capillary blood samples at 3 months were analyzed for serum 25-hydroxyvitamin D, parathyroid hormone, phosphate, calcium and intact and C-terminal FGF23. RESULTS In repeated-measures ANCOVA, intact FGF23 concentration increased with time (p < 0.001) and C-terminal FGF23 decreased (p < 0.001). At 3 months, girls had a higher concentration of intact FGF23 (51 vs. 26 pg/ml, p < 0.001) and a greater increase over time (x0394;FGF23 intact 45 vs. 16 pg/ml, p = 0.001) than boys. Vitamin D did not affect serum intact or C-terminal FGF23 concentrations. Girls showed a positive correlation between phosphate and intact FGF23 (p = 0.004), whereas in boys phosphate and C-terminal FGF23 correlated inversely (p = 0.006). CONCLUSIONS A substantial sex-related difference in intact FGF23 concentration exists during early infancy, possibly related to differences in skeletal growth between boys and girls.
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Affiliation(s)
- Elisa Holmlund-Suila
- Children's Hospital, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
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20
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Plant-based diets relatively low in bioavailable phosphate and calcium may aid prevention and control of prostate cancer by lessening production of fibroblast growth factor 23. Med Hypotheses 2017; 99:68-72. [DOI: 10.1016/j.mehy.2017.01.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Accepted: 01/02/2017] [Indexed: 12/20/2022]
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21
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Braithwaite VS, Freeman R, Greenwood CL, Summers DM, Nigdikar S, Lavy CBD, Offiah AC, Bishop NJ, Cashman J, Prentice A. The aetiology of rickets-like lower limb deformities in Malawian children. Osteoporos Int 2016; 27:2367-2372. [PMID: 27059923 PMCID: PMC4901102 DOI: 10.1007/s00198-016-3541-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 02/08/2016] [Indexed: 01/23/2023]
Abstract
UNLABELLED Debilitating rickets-like lower limb deformities are common in children throughout the world, particularly in Malawi, Africa where the causes are unknown. We have identified that Blount disease and calcium deficiency rickets are the likely causes of these deformities and propose calcium supplementation as a potential treatment of Malawian rickets. INTRODUCTION Surgical correction of rickets-like lower limb deformities is the most common paediatric operation performed at Beit Cure Orthopaedic Hospital, Malawi. The aim of this study was to investigate the aetiology of these deformities. METHODS Children with a tibio-femoral angle of deformity >20° were enrolled (n = 42, 3.0-15.0 years). Anthropometric and early life and well-being data were collected. Early morning serum and urine samples were collected on the morning of the operation for markers of calcium and phosphate homeostasis. Knee radiographs were obtained, and the children were diagnosed with either Blount (BD, n = 22) or evidence of rickets disease (RD, n = 20). As BD is a mechanical rather than metabolic disease, BD were assumed to be biochemically representative of the local population and thus used as a local reference for RD. RESULTS There were no differences in anthropometry or early life experiences between BD and RD. Parathyroid hormone (PTH), 1,25-dihydroxyvitamin D, total alkaline phosphatase and urinary phosphate were significantly higher and serum phosphate, 25-hydroxyvitamin D (25OHD) and tubular maximal reabsorption of phosphate significantly lower in RD than BD. There was no difference in serum calcium, fibroblast growth factor 23 or markers of iron status between groups. All children had 25OHD > 25 nmol/L. CONCLUSIONS Vitamin D deficiency is not implicated in the aetiology of RD or BD in Malawian children. The cause of RD in Malawi is likely to be dietary calcium deficiency leading to elevated PTH resulting in increased losses of phosphate from the bone and glomerular filtrate. The causes of BD remain unclear; there was no evidence in support of previously suggested risk factors such as being overweight or starting to walk early. Prior to surgical intervention, supplementation with calcium should be considered for children with RD.
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Affiliation(s)
- V S Braithwaite
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, UK.
| | - R Freeman
- Department of Paediatric Orthopaedics, Robert Jones Agnes Hunt NHS Foundation Trust, Oswestry, Shropshire, UK
| | - C L Greenwood
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, UK
| | - D M Summers
- Department of Surgery, University of Cambridge, Addenbrooke's Hospital, Cambridge, UK
| | - S Nigdikar
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, UK
| | - C B D Lavy
- Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Science, University of Oxford, Oxford, UK
| | - A C Offiah
- Department of Oncology and Metabolism, Academic Unit of Child Health, University of Sheffield, Sheffield, UK
| | - N J Bishop
- Department of Oncology and Metabolism, Academic Unit of Child Health, University of Sheffield, Sheffield, UK
| | - J Cashman
- Beit Cure Orthopaedic Hospital, Blantyre, Malawi
| | - A Prentice
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge, UK
- MRC Keneba, Keneba, The Gambia
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22
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Yuen SN, Kramer H, Luke A, Bovet P, Plange-Rhule J, Forrester T, Lambert V, Wolf M, Camacho P, Harders R, Dugas L, Cooper R, Durazo-Arvizu R. Fibroblast Growth Factor-23 (FGF-23) Levels Differ Across Populations by Degree of Industrialization. J Clin Endocrinol Metab 2016; 101:2246-53. [PMID: 27003300 PMCID: PMC4870853 DOI: 10.1210/jc.2015-3558] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Compensatory increases in fibroblast growth factor 23 (FGF23) with increasing phosphate intake may adversely impact health. However, population and clinical studies examining the link between phosphate intake and FGF23 levels have focused mainly on populations living in highly industrialized societies in which phosphate exposure may be homogenous. OBJECTIVE The objective of the study was to contrast dietary phosphate intake, urinary measures of phosphate excretion, and FGF23 levels across populations that differ by the level of industrialization. DESIGN This was a cross-sectional analysis of three populations. SETTING The study was conducted in Maywood, Illinois; Mahé Island, Seychelles; and Kumasi, Ghana. PARTICIPANTS Adults with African ancestry aged 25-45 years participated in the study. MAIN OUTCOME FGF23 levels were measured. RESULTS The mean age was 35.1 (6.3) years and 47.9% were male. Mean phosphate intake and fractional excretion of phosphate were significantly higher in the United States vs Ghana, whereas no significant difference in phosphate intake or fractional excretion of phosphate was noted between the United States and Seychelles for men or women. Overall, median FGF23 values were 57.41 RU/mL (interquartile range [IQR] 43.42, 75.09) in the United States, 42.49 RU/mL (IQR 33.06, 55.39) in Seychelles, and 33.32 RU/mL (IQR 24.83, 47.36) in Ghana. In the pooled sample, FGF23 levels were significantly and positively correlated with dietary phosphate intake (r = 0.11; P < .001) and the fractional excretion of phosphate (r = 0.13; P < .001) but not with plasma phosphate levels (r = -0.001; P = .8). Dietary phosphate intake was significantly and positively associated with the fractional excretion of phosphate (r = 0.23; P < .001). CONCLUSION The distribution of FGF23 levels in a given population may be influenced by the level of industrialization, likely due to differences in access to foods preserved with phosphate additives.
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Affiliation(s)
- Shennin N Yuen
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Holly Kramer
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Amy Luke
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Pascal Bovet
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Jacob Plange-Rhule
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Terrence Forrester
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Vicki Lambert
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Myles Wolf
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Pauline Camacho
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Regina Harders
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Lara Dugas
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Richard Cooper
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
| | - Ramon Durazo-Arvizu
- Departments of Public Health Sciences (S.N.Y., H.K., A.L., R.H., L.D., R.C., R.D.-A.) and Medicine (H.K.), Division of Nephrology and Hypertension, and Division of Endocrinology (P.C.), Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153; Institute of Social and Preventive Medicine (P.B.), Division of Chronic Disease, Biopole 2, Bureau no. 01-171, 1010 Lausanne, Switzerland; Ministry of Health (P.B.), Victoria, Republic of Seychelles; School of Medical Sciences, Kwame Nkrumah University of Science and Technology (J.P.-R.), Kumasi, Ghana; Tropical Medicine Research Institute (T.F.), University of the West Indies, Solutions for Developing Countries, Mona, Kingston 7, Jamaica; Department of Human Biology (V.L.), Division of Exercise Science and Sports Medicine, Division of Exercise Science and Sports Medicine Department of Human Biology, Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, 7725 Cape Town, South Africa and Institute of Public Health Sciences (M.W.), Northwestern Medical Center, Chicago, Illinois 60208
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Imel EA, Liu Z, McQueen AK, Acton D, Acton A, Padgett LR, Peacock M, Econs MJ. Serum fibroblast growth factor 23, serum iron and bone mineral density in premenopausal women. Bone 2016; 86:98-105. [PMID: 26965530 PMCID: PMC4839198 DOI: 10.1016/j.bone.2016.03.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 01/25/2016] [Accepted: 03/05/2016] [Indexed: 10/22/2022]
Abstract
Fibroblast growth factor 23 (FGF23) circulates as active protein and inactive fragments. Low iron status increases FGF23 gene expression, and iron deficiency is common. We hypothesized that in healthy premenopausal women, serum iron influences C-terminal and intact FGF23 concentrations, and that iron and FGF23 associate with bone mineral density (BMD). Serum iron, iron binding capacity, percent iron saturation, phosphorus, and other biochemistries were measured in stored fasting samples from healthy premenopausal white (n=1898) and black women (n=994), age 20-55years. Serum C-terminal and intact FGF23 were measured in a subset (1631 white and 296 black women). BMD was measured at the lumbar spine and femur neck. Serum phosphorus, calcium, alkaline phosphatase and creatinine were lower in white women than black women (p<0.001). Serum iron (p<0.0001) and intact FGF23 (p<0.01) were higher in white women. C-terminal FGF23 did not differ between races. Phosphorus correlated with intact FGF23 (white women, r=0.120, p<0.0001; black women r=0.163, p<0.01). However, phosphorus correlated with C-terminal FGF23 only in black women (r=0.157, p<0.01). Intact FGF23 did not correlate with iron. C-terminal FGF23 correlated inversely with iron (white women r=-0.134, p<0.0001; black women r=-0.188, p<0.01), having a steeper slope at iron <50mcg/dl than ≥50mcg/dl. Longitudinal changes in iron predicted changes in C-terminal FGF23. Spine BMD correlated with iron negatively (r=-0.076, p<0.01) in white women; femur neck BMD correlated with iron negatively (r=-0.119, p<0.0001) in black women. Both relationships were eliminated in weight-adjusted models. BMD did not correlate with FGF23. Serum iron did not relate to intact FGF23, but was inversely related to C-terminal FGF23. Intact FGF23 correlated with serum phosphorus. In weight-adjusted models, BMD was not related to intact FGF23, C-terminal FGF23 or iron. The influence of iron on FGF23 gene expression is not important in determining bone density in healthy premenopausal women.
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Affiliation(s)
- Erik A Imel
- Department of Medicine, Indiana University School of Medicine, USA; Department of Pediatrics, Indiana University School of Medicine, USA.
| | - Ziyue Liu
- Indiana University School of Public Health, Department of Biostatistics, USA
| | - Amie K McQueen
- Department of Medicine, Indiana University School of Medicine, USA
| | - Dena Acton
- Department of Medicine, Indiana University School of Medicine, USA
| | - Anthony Acton
- Department of Medicine, Indiana University School of Medicine, USA
| | - Leah R Padgett
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, USA
| | - Munro Peacock
- Department of Medicine, Indiana University School of Medicine, USA
| | - Michael J Econs
- Department of Medicine, Indiana University School of Medicine, USA; Medical and Molecular Genetics, Indiana University School of Medicine, USA
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24
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Marchelek-Myśliwiec M, Różański J, Ogrodowczyk A, Dutkiewicz G, Dołęgowska B, Sałata D, Budkowska M, Safranow K, Stępniewska J, Wiśniewska M, Ciechanowski K. The association of the Klotho polymorphism rs9536314 with parameters of calcium-phosphate metabolism in patients on long-term hemodialysis. Ren Fail 2016; 38:776-80. [PMID: 27055909 DOI: 10.3109/0886022x.2016.1162062] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Patients on long-term hemodialysis frequently suffer from complications, such as secondary hyperparathyroidism, bone fractures, and arteriosclerosis. The process of regulating Ca/P metabolism depends on factors, such as FGF23 and Klotho. This study aimed to answer the question of whether the Klotho polymorphism rs9536314 is associated with FGF23 plasma concentration. METHODS In 118 patients undergoing hemodialysis, blood was collected before and after hemodialysis. The following parameters were measured in plasma: FGF23, serum: Ca, P, PTH, HGB, and iron concentrations. The KL gene polymorphism rs9536314 was identified by PCR-RFLP. RESULTS The KL polymorphism rs9536314 was not associated with Ca, P, PTH, or FGF23. There was a negative correlation between FGF23 and blood HGB levels and positive correlation between FGF23 and ESA dose. CONCLUSIONS The results obtained may indicate that there is no association between the KL polymorphism and FGF23 concentration in patients undergoing long-term.
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Affiliation(s)
| | - Jacek Różański
- a Department of Nephrology, Transplantology and Internal Diseases , Pomeranian Medical University , Szczecin , Poland
| | - Aldona Ogrodowczyk
- a Department of Nephrology, Transplantology and Internal Diseases , Pomeranian Medical University , Szczecin , Poland
| | - Grażyna Dutkiewicz
- a Department of Nephrology, Transplantology and Internal Diseases , Pomeranian Medical University , Szczecin , Poland
| | - Barbara Dołęgowska
- b Department of Medical Analytics , Pomeranian Medical University , Szczecin , Poland
| | - Daria Sałata
- b Department of Medical Analytics , Pomeranian Medical University , Szczecin , Poland
| | - Marta Budkowska
- b Department of Medical Analytics , Pomeranian Medical University , Szczecin , Poland
| | - Krzysztof Safranow
- c Department of Biochemistry and Medical Chemistry , Pomeranian Medical University , Szczecin , Poland
| | - Joanna Stępniewska
- a Department of Nephrology, Transplantology and Internal Diseases , Pomeranian Medical University , Szczecin , Poland
| | - Magda Wiśniewska
- a Department of Nephrology, Transplantology and Internal Diseases , Pomeranian Medical University , Szczecin , Poland
| | - Kazimierz Ciechanowski
- a Department of Nephrology, Transplantology and Internal Diseases , Pomeranian Medical University , Szczecin , Poland
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Koller DL, Imel EA, Lai D, Padgett LR, Acton D, Gray A, Peacock M, Econs MJ, Foroud T. Genome-wide association study of serum iron phenotypes in premenopausal women of European descent. Blood Cells Mol Dis 2016; 57:50-3. [PMID: 26852655 PMCID: PMC4746500 DOI: 10.1016/j.bcmd.2015.12.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 12/02/2015] [Indexed: 10/22/2022]
Abstract
A genome-wide association study was performed on 1130 premenopausal women to detect common variants associated with three serum iron-related phenotypes. Total iron binding capacity was strongly associated (p=10(-14)) with variants in and near the TF gene (transferrin), the serum iron transporting protein, and with variants in HFE (p=4×10(-7)), which encodes the human hemochromatosis gene. Association was also detected between percent iron saturation (p=10(-8)) and variants in the chromosome 6 region containing both HFE and SLC17A2, which encodes a phosphate transport protein. No significant associations were detected with serum iron, but variants in HFE were suggestive (p=10(-6)). Our results corroborate prior studies in older subjects and demonstrate that the association of these genetic variants with iron phenotypes can be detected in premenopausal women.
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Affiliation(s)
- Daniel L Koller
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
| | - Erik A Imel
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Dongbing Lai
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Leah R Padgett
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Dena Acton
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Amie Gray
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Munro Peacock
- Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Michael J Econs
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Tatiana Foroud
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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Braithwaite VS, Prentice A, Darboe MK, Prentice AM, Moore SE. The effects of maternal iron deficiency on infant fibroblast growth factor-23 and mineral metabolism. Bone 2016; 83:1-8. [PMID: 26453792 PMCID: PMC4720219 DOI: 10.1016/j.bone.2015.10.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Revised: 09/25/2015] [Accepted: 10/05/2015] [Indexed: 12/16/2022]
Abstract
Fibroblast growth factor-23 (FGF23), a phosphate(Phos)-regulating hormone, is abnormally elevated in hypophosphataemic syndromes and an elevated FGF23 is a predictor of mortality in kidney disease. Recent findings suggest iron deficiency as a potential mediator of FGF23 expression and murine studies have shown in utero effects of maternal iron deficiency on offspring FGF23 and phosphate metabolism. Our aim was to investigate the impact of maternal iron status on infant FGF23 and mineral metabolites over the first 2years of life. Infants born to mothers with normal (NIn=25,) and low (LIn=25) iron status during pregnancy, from a mother-infant trial (ISRCTN49285450) in rural Gambia, West Africa, had blood and plasma samples analysed at 12, 24, 52, 78 and 104weeks (wk) of age. Circulating intact-FGF23 (I-FGF23), Phos, total alkaline phosphatase (TALP) and haemoglobin (Hb) decreased and estimated glomerular filtration rate increased over time [all P≤0.0001)]. C-terminal-FGF23 (C-FGF23) and TALP were significantly higher in LI compared with NI, from 52wk for C-FGF23 [Beta coefficient (SE) 18.1 (0.04) %, P=0.04] and from 24wk for TALP [44.7 (29.6) U/L, P=0.04]. Infant Hb was the strongest negative predictor of C-FGF23 concentration [-21% (4%) RU/mL, P≤0.0001], Phos was the strongest positive predictor of I-FGF23 [32.0(3.9) pg/mL, P≤0.0001] and I-FGF23 did not predict C-FGF23 over time [-0.5% (0.5%), P=0.3]. In conclusion, this study suggests that poor maternal iron status is associated with a higher infant C-FGF23 and TALP but similar I-FGF23 concentrations in infants and young children. These findings further highlight the likely public health importance of preventing iron deficiency during pregnancy. Whether or not children who are born to iron deficient mothers have persistently high concentrations of these metabolites and are more likely to be at risk of impaired bone development and pre-disposed to rickets requires further research.
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Affiliation(s)
- V S Braithwaite
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK and MRC Unit, The Gambia.
| | - A Prentice
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK and MRC Unit, The Gambia
| | - M K Darboe
- MRC International Nutrition Group at London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT, UK and MRC Unit, The Gambia
| | - A M Prentice
- MRC International Nutrition Group at London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT, UK and MRC Unit, The Gambia
| | - S E Moore
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK and MRC Unit, The Gambia; MRC International Nutrition Group at London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT, UK and MRC Unit, The Gambia
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Tran L, Batech M, Rhee CM, Streja E, Kalantar-Zadeh K, Jacobsen SJ, Sim JJ. Serum phosphorus and association with anemia among a large diverse population with and without chronic kidney disease. Nephrol Dial Transplant 2015; 31:636-45. [PMID: 26254460 DOI: 10.1093/ndt/gfv297] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2015] [Accepted: 07/09/2015] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND We hypothesized that phosphorus has an effect on anemia in both normal kidney function and early chronic kidney disease (CKD). We sought to determine whether higher phosphorus levels are associated with anemia in a large diverse population without CKD and early CKD. METHODS This study is a historical population-based study within the Kaiser Permanente Southern California health system (1 January 1998 to 31 December 2013) among individuals aged 18 years and older with estimated glomerular filtration rate >30 mL/min/1.73 m(2) and measurements of serum phosphorus, creatinine and hemoglobin. Individuals were excluded if they had secondary causes of anemia. Odds ratio (OR) estimated for moderate anemia defined as hemoglobin <11 g/dL for both sexes. Mild anemia was defined as <12 g/dL (females) and <13 g/dL (males). RESULTS Among 155 974 individuals, 4.1% had moderate anemia and 12.9% had mild anemia. Serum phosphorus levels ≥3.5 mg/dL were associated with both mild and moderate anemia. Moderate anemia OR (95% confidence interval) was 1.16 (1.04-1.29) for every 0.5 mg/dL phosphorus increase and 1.26 (1.07-1.48) in the highest versus middle phosphorus tertile. Additional independent anemia risk factors, including female sex, Asian race, diabetes, low albumin and low iron saturation, were observed, but did not alter the anemia-phosphorus association. CONCLUSIONS Higher phosphorus levels were associated with a greater likelihood for anemia in a population with early CKD and normal kidney function. Phosphorus may be a biomarker for anemia and may affect aspects of hematopoiesis.
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Affiliation(s)
- Lac Tran
- Division of Nephrology and Hypertension, Kaiser Permanente Los Angeles Medical Center, Los Angeles, CA, USA
| | - Michael Batech
- Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA, USA
| | - Connie M Rhee
- Division of Nephrology and Hypertension, University of California Irvine School of Medicine, University of California Irvine Medical Center, Irvine, CA, USA
| | - Elani Streja
- Division of Nephrology and Hypertension, University of California Irvine School of Medicine, University of California Irvine Medical Center, Irvine, CA, USA
| | - Kamyar Kalantar-Zadeh
- Division of Nephrology and Hypertension, University of California Irvine School of Medicine, University of California Irvine Medical Center, Irvine, CA, USA
| | - Steven J Jacobsen
- Department of Research and Evaluation, Kaiser Permanente Southern California, Pasadena, CA, USA
| | - John J Sim
- Division of Nephrology and Hypertension, Kaiser Permanente Los Angeles Medical Center, Los Angeles, CA, USA
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Jones HL, Jammeh L, Owens S, Fulford AJ, Moore SE, Pettifor JM, Prentice A. Prevalence of rickets-like bone deformities in rural Gambian children. Bone 2015; 77:1-5. [PMID: 25871880 PMCID: PMC4456426 DOI: 10.1016/j.bone.2015.04.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Revised: 04/01/2015] [Accepted: 04/06/2015] [Indexed: 11/20/2022]
Abstract
The aim of this study was to estimate the burden of childhood rickets-like bone deformity in a rural region of West Africa where rickets has been reported in association with a low calcium intake. A population-based survey of children aged 0.5-17.9 years living in the province of West Kiang, The Gambia was conducted in 2007. 6221 children, 92% of those recorded in a recent census, were screened for physical signs of rickets by a trained survey team with clinical referral of suspected cases. Several objective measures were tested as potential screening tools. The prevalence of bone deformity in children <18.0 years was 3.3%. The prevalence was greater in males (M = 4.3%, F = 2.3%, p < 0.001) and in children <5.0 years (5.7%, M = 8.3%, F = 2.9%). Knock-knee was more common (58%) than bow-leg (31%) or windswept deformity (9%). Of the 196 examined clinically, 36 were confirmed to have a deformity outside normal variation (47% knock-knee, 53% bow-leg), resulting in more conservative prevalence estimates of bone deformity: 0.6% for children <18.0 years (M = 0.9%, F = 0.2%), 1.5% for children < 5.0 years (M = 2.3%, F = 0.6%). Three of these children (9% of those with clinically-confirmed deformity, 0.05% of those screened) had active rickets on X-ray at the time of medical examination. This emphasises the difficulties in comparing prevalence estimates of rickets-like bone deformities from population surveys and clinic-based studies. Interpopliteal distance showed promise as an objective screening measure for bow-leg deformity. In conclusion, this population survey in a rural region of West Africa with a low calcium diet has demonstrated a significant burden of rickets-like bone deformity, whether based on physical signs under survey conditions or after clinical examination, especially in boys < 5.0 years.
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Affiliation(s)
- Helen L Jones
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK; MRC Keneba, The Gambia
| | | | - Stephen Owens
- MRC Keneba, The Gambia; Northumbria Healthcare NHS Foundation Trust, UK
| | - Anthony J Fulford
- MRC Keneba, The Gambia; MRC International Nutrition Group, London School of Hygiene and Tropical Medicine, London, UK
| | - Sophie E Moore
- MRC Keneba, The Gambia; MRC International Nutrition Group, London School of Hygiene and Tropical Medicine, London, UK
| | - John M Pettifor
- MRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Ann Prentice
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge, UK; MRC Keneba, The Gambia.
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Braithwaite VS, Jones KS, Schoenmakers I, Silver M, Prentice A, Hennig BJ. Vitamin D binding protein genotype is associated with plasma 25OHD concentration in West African children. Bone 2015; 74:166-70. [PMID: 25652210 PMCID: PMC4366041 DOI: 10.1016/j.bone.2014.12.068] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/09/2014] [Accepted: 12/15/2014] [Indexed: 01/08/2023]
Abstract
Vitamin D is well known for its role in promoting skeletal health. Vitamin D status is determined conventionally by circulating 25-dihydroxyvitamin D (25OHD) concentration. There is evidence indicating that circulating 25OHD concentration is affected by variation in Gc, the gene encoding the vitamin D binding protein (DBP). The composite genotype of two single nucleotide polymorphisms (rs7041 and rs4588) results in different DBP isotypes (Gc1f, Gc1s and Gc2). The protein configurational differences among DBP isotypes affect DBP substrate binding affinity. The aims of this study were to determine 1) Gc variant frequencies in a population from an isolated rural region of The Gambia, West Africa (n=3129) with year-round opportunity for cutaneous vitamin D synthesis and 2) the effects of Gc variants on 25OHD concentration (n=237) in a genetically representative sub-group of children (mean (SD) age: 11.9 (4.8) years). The distribution of Gc variants was Gc1f: 0.86, Gc1s: 0.11 and Gc2: 0.03. The mean (SD) concentration of 25OHD was 59.6 (12.9) nmol/L and was significantly higher in those homozygous for Gc1f compared to other Gc variants (60.7 (13.1) vs. 56.6 (12.1) nmol/L, P=0.03). Plasma 25OHD and 1,25(OH)2D concentration was significantly associated with parathyroid hormone in Gc1f-1f but not in the other Gc variants combined. This study demonstrates that different Gc variants are associated with different 25OHD concentrations in a rural Gambian population. Gc1f-1f, thought to have the highest affinity for 25OHD, had the highest 25OHD concentration compared with lower affinity Gc variants. The considerable difference in Gc1f frequency observed in Gambians compared with other non-West African populations and associated differences in plasma 25OHD concentration, may have implications for the way in which vitamin D status should be interpreted across different ancestral groups.
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Affiliation(s)
- V S Braithwaite
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK.
| | - K S Jones
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK
| | - I Schoenmakers
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK
| | - M Silver
- MRC International Nutrition Group at London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT UK and MRC Unit, The Gambia
| | - A Prentice
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Fulbourn Road, Cambridge CB1 9NL, UK; MRC Keneba, Keneba, The Gambia
| | - B J Hennig
- MRC International Nutrition Group at London School of Hygiene & Tropical Medicine, Keppel St, London WC1E 7HT UK and MRC Unit, The Gambia
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Eckberg K, Kramer H, Wolf M, Durazo-Arvizu R, Tayo B, Luke A, Cooper R. Impact of westernization on fibroblast growth factor 23 levels among individuals of African ancestry. Nephrol Dial Transplant 2015; 30:630-5. [PMID: 25358495 PMCID: PMC4370291 DOI: 10.1093/ndt/gfu342] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/24/2014] [Indexed: 12/23/2022] Open
Abstract
INTRODUCTION The Western diet is associated with high consumption of processed foods preserved with phosphate. Higher dietary phosphate consumption stimulates production of fibroblast growth factor 23 (FGF23), which heightens risk for cardiovascular disease and mortality. We hypothesized that adults living in a more westernized society have higher levels of FGF23 due to increased phosphate consumption as measured by urinary phosphate excretion. METHODS We measured plasma C-terminal FGF23 levels and urinary phosphate and creatinine levels in timed urine collections among 100 African adults living in the rural area of Igbo-Ora, Nigeria (52 women, 48 men), and 100 African Americans (32 women, 68 men) living in Maywood, IL, an urban suburb of Chicago, IL, USA. Among these 200 participants, urine collections were adequate in 76 and 68 of the Maywood and Igbo-Ora participants, respectively. RESULTS In the total group, the mean age and body mass index, respectively, were 34.6 ± 8.2 years and 22.1 ± 3.9 kg/m(2) in Igbo-Ora, and 42.8 ± 7.2 years and 25.8 ± 6.5 kg/m(2) in Maywood. Demographic characteristics for each site were very similar after excluding participants without adequate urine collections. Among all 200 participants, the median (interquartile range) FGF23 levels were significantly higher in Maywood versus Igbo-Ora [63.8 (45.0-89.9) versus 12.5 RU/mL (8.5-18.5); P < 0.0001] and these differences did not change substantially after excluding nine women from Maywood with FGF23 levels >400 RU/mL or after excluding participants with inadequate urine collections. Among participants with adequate urine collections, the mean 24-h urinary phosphate excretion was significantly higher in Maywood versus Igbo-Ora (810.6 ± 309.0 versus 347.5 ± 153.1 mg; P < 0.001) and FGF23 levels correlated significantly with total urinary phosphate excretion (r = 0.62; P < 0.001) and urinary phosphate-to-creatinine ratios (r = 0.50; P < 0.001). CONCLUSIONS Living in a more westernized society may be associated with greater net phosphate absorption, as reflected by higher urinary phosphate excretion, and higher FGF23 levels.
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Affiliation(s)
- Karl Eckberg
- Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
| | - Holly Kramer
- Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
- Division of Nephrology and Hypertension, Department of Medicine, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
| | - Myles Wolf
- Division of Nephrology and Hypertension, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
- Institute for Public Health and Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Ramon Durazo-Arvizu
- Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
| | - Bamidele Tayo
- Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
| | - Amy Luke
- Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
| | - Richard Cooper
- Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
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Coupling fibroblast growth factor 23 production and cleavage: iron deficiency, rickets, and kidney disease. Curr Opin Nephrol Hypertens 2015; 23:411-9. [PMID: 24867675 DOI: 10.1097/01.mnh.0000447020.74593.6f] [Citation(s) in RCA: 149] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
PURPOSE OF REVIEW High levels of fibroblast growth factor 23 (FGF23) cause the rare disorders of hypophosphatemic rickets and are a risk factor for cardiovascular disease and death in patients with chronic kidney disease (CKD). Despite major advances in understanding FGF23 biology, fundamental aspects of FGF23 regulation in health and in CKD remain mostly unknown. RECENT FINDINGS Autosomal dominant hypophosphatemic rickets (ADHR) is caused by gain-of-function mutations in FGF23 that prevent its proteolytic cleavage, but affected individuals experience a waxing and waning course of phosphate wasting. This led to the discovery that iron deficiency is an environmental trigger that stimulates FGF23 expression and hypophosphatemia in ADHR. Unlike osteocytes in ADHR, normal osteocytes couple increased FGF23 production with commensurately increased FGF23 cleavage to ensure that normal phosphate homeostasis is maintained in the event of iron deficiency. Simultaneous measurement of FGF23 by intact and C-terminal assays supported these breakthroughs by providing minimally invasive insight into FGF23 production and cleavage in bone. These findings also suggest a novel mechanism of FGF23 elevation in patients with CKD, who are often iron deficient and demonstrate increased FGF23 production and decreased FGF23 cleavage, consistent with an acquired state that mimics the molecular pathophysiology of ADHR. SUMMARY Iron deficiency stimulates FGF23 production, but normal osteocytes couple increased FGF23 production with increased cleavage to maintain normal circulating levels of biologically active hormone. These findings uncover a second level of FGF23 regulation within osteocytes, failure of which culminates in elevated levels of biologically active FGF23 in ADHR and perhaps CKD.
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Bożentowicz-Wikarek M, Kocełak P, Owczarek A, Olszanecka-Glinianowicz M, Mossakowska M, Skalska A, Więcek A, Chudek J. Plasma fibroblast growth factor 23 concentration and iron status. Does the relationship exist in the elderly population? Clin Biochem 2015; 48:431-6. [PMID: 25583093 DOI: 10.1016/j.clinbiochem.2014.12.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/29/2014] [Accepted: 12/30/2014] [Indexed: 01/04/2023]
Abstract
OBJECTIVE Fibroblast growth factor 23 (FGF23) is a phosphaturic agent involved in calcium-phosphate homeostasis. Recent findings show that iron deficiency and inflammation regulate FGF23 release and/or biodegradation. Iron deficiency is frequently observed in the elderly, therefore the aim of this study was to find out if iron deficiency is independent from low grade inflammatory factors affecting both forms of FGF23 that are detectable in circulation in a large population-based study of elderly subjects. DESIGN AND METHODS The analysis included 3780 elderly (1798 females) PolSenior study participants and assessed levels of phosphorus, calcium, iron, ferritin, interleukin 6, C-reactive protein (hs-CRP), intact (iFGF23), and c-terminal FGF (cFGF23). The analysis was performed for all subjects and terciles of serum iron levels in relation to hs-CRP were calculated. RESULTS The highest plasma cFGF23 and iFGF23 concentrations were found in subjects with the lowest serum iron levels (p<0.001). The effect of low grade inflammation was markedly weaker and affected only iFGF23 levels. The adjusted serum levels of hs-CRP, iPTH, phosphorus, and 25-(OH)-D3 analysis revealed that plasma iFGF23 and cFGF23 levels were almost unchanged up to a serum iron level of 59.3 ng/mL and 57.3 ng/mL respectively and then were nearly linearly increasing by 0.285 pg/mL and 3.742 RU/mL for each unit of serum iron increase. CONCLUSIONS Low iron levels are associated with increased levels of both cFGF23 and iFGF23, independent of low grade inflammation. A similar analysis of cFGF23 and iFGF23 does not suggest enhanced biodegradation of iFGF23 induced by iron deficiency.
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Affiliation(s)
- Maria Bożentowicz-Wikarek
- Pathophysiology Unit, Department of Pathophysiology, Medical Faculty in Katowice, Medical University of Silesia, Katowice, Poland
| | - Piotr Kocełak
- Health Promotion and Obesity Management Unit, Department of Pathophysiology, Medical Faculty in Katowice, Medical University of Silesia, Katowice, Poland
| | - Aleksander Owczarek
- Division of Statistics, Department of Instrumental Analysis, Faculty of Pharmacy and Laboratory Medicine in Sosnowiec Medical University of Silesia, Katowice, Poland
| | - Magdalena Olszanecka-Glinianowicz
- Health Promotion and Obesity Management Unit, Department of Pathophysiology, Medical Faculty in Katowice, Medical University of Silesia, Katowice, Poland
| | | | - Anna Skalska
- Department of Internal Medicine and Gerontology, Jagiellonian University Medical College, Krakow, Poland
| | - Andrzej Więcek
- Department of Nephrology, Transplantation and Internal Medicine, Medical Faculty in Katowice, Medical University of Silesia, Katowice, Poland
| | - Jerzy Chudek
- Pathophysiology Unit, Department of Pathophysiology, Medical Faculty in Katowice, Medical University of Silesia, Katowice, Poland.
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Clinkenbeard EL, Farrow EG, Summers LJ, Cass TA, Roberts JL, Bayt CA, Lahm T, Albrecht M, Allen MR, Peacock M, White KE. Neonatal iron deficiency causes abnormal phosphate metabolism by elevating FGF23 in normal and ADHR mice. J Bone Miner Res 2014; 29:361-9. [PMID: 23873717 PMCID: PMC5240191 DOI: 10.1002/jbmr.2049] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/01/2013] [Accepted: 07/16/2013] [Indexed: 12/20/2022]
Abstract
Fibroblast growth factor 23 (FGF23) gain of function mutations can lead to autosomal dominant hypophosphatemic rickets (ADHR) disease onset at birth, or delayed onset following puberty or pregnancy. We previously demonstrated that the combination of iron deficiency and a knock-in R176Q FGF23 mutation in mature mice induced FGF23 expression and hypophosphatemia that paralleled the late-onset ADHR phenotype. Because anemia in pregnancy and in premature infants is common, the goal of this study was to test whether iron deficiency alters phosphate handling in neonatal life. Wild-type (WT) and ADHR female breeder mice were provided control or iron-deficient diets during pregnancy and nursing. Iron-deficient breeders were also made iron replete. Iron-deficient WT and ADHR pups were hypophosphatemic, with ADHR pups having significantly lower serum phosphate (p < 0.01) and widened growth plates. Both genotypes increased bone FGF23 mRNA (>50 fold; p < 0.01). WT and ADHR pups receiving low iron had elevated intact serum FGF23; ADHR mice were affected to a greater degree (p < 0.01). Iron-deficient mice also showed increased Cyp24a1 and reduced Cyp27b1, and low serum 1,25-dihydroxyvitamin D (1,25D). Iron repletion normalized most abnormalities. Because iron deficiency can induce tissue hypoxia, oxygen deprivation was tested as a regulator of FGF23, and was shown to stimulate FGF23 mRNA in vitro and serum C-terminal FGF23 in normal rats in vivo. These studies demonstrate that FGF23 is modulated by iron status in young WT and ADHR mice and that hypoxia independently controls FGF23 expression in situations of normal iron. Therefore, disturbed iron and oxygen metabolism in neonatal life may have important effects on skeletal function and structure through FGF23 activity on phosphate regulation.
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Affiliation(s)
- Erica L Clinkenbeard
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Emily G Farrow
- Clinical Center for Pediatric Genomic Medicine, Children’s Mercy Hospitals Clinics, Kansas City, MO, USA
| | - Lelia J Summers
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Taryn A Cass
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jessica L Roberts
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Christine A Bayt
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Tim Lahm
- Division of Pulmonary, Allergy, Critical Care and Occupational Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Marjorie Albrecht
- Division of Pulmonary, Allergy, Critical Care and Occupational Medicine, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Matthew R Allen
- Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Munro Peacock
- Division of Endocrinology and Metabolism, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kenneth E White
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
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Osteocyte Communication with the Kidney Via the Production of FGF23: Remote Control of Phosphate Homeostasis. Clin Rev Bone Miner Metab 2014. [DOI: 10.1007/s12018-014-9155-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Braithwaite V, Jones KS, Assar S, Schoenmakers I, Prentice A. Predictors of intact and C-terminal fibroblast growth factor 23 in Gambian children. Endocr Connect 2013; 3:1-10. [PMID: 24258305 PMCID: PMC3869962 DOI: 10.1530/ec-13-0070] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2013] [Accepted: 11/20/2013] [Indexed: 12/16/2022]
Abstract
Elevated C-terminal fibroblast growth factor 23 (C-FGF23) concentrations have been reported in Gambian children with and without putative Ca-deficiency rickets. The aims of this study were to investigate whether i) elevated C-FGF23 concentrations in Gambian children persist long term; ii) they are associated with higher intact FGF23 concentrations (I-FGF23), poor iron status and shorter 25-hydroxyvitamin D half-life (25OHD-t1/2); and iii) the persistence and predictors of elevated FGF23 concentrations differ between children with and without a history of rickets. Children (8-16 years, n=64) with a history of rickets and a C-FGF23 concentration >125 RU/ml (bone deformity (BD), n=20) and local community children with a previously measured elevated C-FGF23 concentration (LC+, n=20) or a previously measured C-FGF23 concentration within the normal range (LC-, n=24) participated. BD children had no remaining signs of bone deformities. C-FGF23 concentration had normalised in BD children, but remained elevated in LC+ children. All the children had I-FGF23 concentration within the normal range, but I-FGF23 concentration was higher and iron status poorer in LC+ children. 1,25-dihydroxyvitamin D was the strongest negative predictor of I-FGF23 concentration (R(2)=18%; P=0.0006) and soluble transferrin receptor was the strongest positive predictor of C-FGF23 concentration (R(2)=33%; P≤0.0001). C-FGF23 and I-FGF23 concentrations were poorly correlated with each other (R(2)=5.3%; P=0.07). 25OHD-t1/2 was shorter in BD children than in LC- children (mean (s.d.): 24.5 (6.1) and 31.5 (11.5) days respectively; P=0.05). This study demonstrated that elevated C-FGF23 concentrations normalised over time in Gambian children with a history of rickets but not in local children, suggesting a different aetiology; that children with resolved rickets had a shorter 25OHD-t1/2, suggesting a long-standing increased expenditure of 25OHD, and that iron deficiency is a predictor of elevated C-FGF23 concentrations in both groups of Gambian children.
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Affiliation(s)
- Vickie Braithwaite
- Medical Research Council (MRC) Human Nutrition ResearchElsie Widdowson LaboratoriesFulbourn Road, Cambridge, CB1 9NLUK
| | - Kerry S Jones
- Medical Research Council (MRC) Human Nutrition ResearchElsie Widdowson LaboratoriesFulbourn Road, Cambridge, CB1 9NLUK
- MRC Keneba, KenebaWest KiangThe Gambia
| | - Shima Assar
- Medical Research Council (MRC) Human Nutrition ResearchElsie Widdowson LaboratoriesFulbourn Road, Cambridge, CB1 9NLUK
| | - Inez Schoenmakers
- Medical Research Council (MRC) Human Nutrition ResearchElsie Widdowson LaboratoriesFulbourn Road, Cambridge, CB1 9NLUK
| | - Ann Prentice
- Medical Research Council (MRC) Human Nutrition ResearchElsie Widdowson LaboratoriesFulbourn Road, Cambridge, CB1 9NLUK
- MRC Keneba, KenebaWest KiangThe Gambia
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Abstract
PURPOSE OF REVIEW The purpose of this study is to review the regulation of phosphate and recent progress in fibroblast growth factor-23 (FGF-23), a key phosphate regulatory hormone. RECENT FINDINGS Phosphate is required for mineralization of bone, muscle strength and a host of biologic functions. Phosphate is sensed by bone that responds with secretion of FGF-23. The major action of FGF-23 is to stimulate phosphaturia. Feedback loops between FGF-23, 1,25-dihydroxyvitamin D3 and parathyroid hormone maintain phosphate homeostasis. Information about FGF-23 has accumulated from studies in patients with oncogenic osteomalacia and inherited disorders of phosphate wasting rickets that explains the pathophysiology. Exciting new discoveries have highlighted FGF-23 as an independent risk factor for cardiovascular disease in patients with chronic kidney disease. The phosphate sensor triggering FGF-23 production remains to be identified. SUMMARY Derangements in FGF-23 production, half-life or downstream response are responsible for several disorders of phosphate wasting, rickets and oncogenic osteomalacia. Very high levels of FGF-23 in renal failure are an independent risk for cardiovascular disease.
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Affiliation(s)
- Mark S Nanes
- Department of Medicine, Atlanta VA Medical Center and Division of Endocrinology, Lipids, and Metabolism, Emory University School of Medicine, Atlanta, Georgia, USA
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Prentice A. Nutritional rickets around the world. J Steroid Biochem Mol Biol 2013; 136:201-6. [PMID: 23220549 DOI: 10.1016/j.jsbmb.2012.11.018] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 11/16/2012] [Accepted: 11/28/2012] [Indexed: 10/27/2022]
Abstract
Nutritional rickets is a major public health problem in many countries of the world. The disease is characterized by deformities of the long bones, enlargement of the wrists and costochondral junctions, hypotonia and, in infants, craniotabes and delayed fontanelle closure. Predominantly caused by severe vitamin D deficiency, rickets can also be associated with hypocalcemic seizures and cardiac failure. First presentation is typically at 6-24 months of age, although hypocalcemia may be evident in younger infants. In many affluent industrialized countries, the prevalence of rickets in the general population diminished after the introduction of clean-air legislation and dietary supplementation. However, in such countries, vitamin-D deficiency rickets has re-emerged in recent years, particularly among groups with limited exposure to UVB-containing sunshine. Infants at risk of rickets tend to be those whose mothers had poor vitamin D status during pregnancy and those exclusively breast-fed for a prolonged period with little skin exposure to UVB. In other countries of the world, the prevalence of rickets can be high, even in regions with abundant year-round UVB-containing sunshine. In general, this is also due to vitamin D deficiency related to limited sun exposure. However, reports from Africa and Asia suggest that there may be other etiological factors involved. Studies in South Africa, Nigeria, The Gambia and Bangladesh have identified rickets in children, typically 3-5 years old at first presentation, in whom plasma 25-hydroxyvitamin D concentrations are higher than those characteristic of primary vitamin D deficiency. Calcium deficiency has been implicated, and in some, but not all, disturbances of phosphate metabolism, renal compromise and iron deficiency may also be involved. Continuing studies of the etiology of nutritional rickets will provide evidence to underpin guidelines for the prevention and treatment of rickets world-wide. This article is part of a Special Issue entitled 'Vitamin D Workshop'.
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Affiliation(s)
- Ann Prentice
- MRC Human Nutrition Research, Cambridge, United Kingdom.
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Memon I, Norris KC, Bomback AS, Peralta C, Li S, Chen SC, McCullough PA, Whaley-Connell A, Jurkovitz C, Tamura MK, Saab G. The Association between Parathyroid Hormone Levels and Hemoglobin in Diabetic and Nondiabetic Participants in the National Kidney Foundation's Kidney Early Evaluation Program. Cardiorenal Med 2013; 3:120-127. [PMID: 23922552 DOI: 10.1159/000351229] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 04/10/2013] [Indexed: 01/18/2023] Open
Abstract
BACKGROUND Both anemia and secondary hyperparathyroidism are reflections of hormonal failure in chronic kidney disease (CKD). While the association of elevated levels of parathyroid hormone (PTH) and anemia has been studied among those with advanced CKD, less is known about this association in mild-to-moderate CKD. METHODS In a cross-sectional analysis, the relationship between PTH and hemoglobin levels was investigated in 10,750 participants in the National Kidney Foundation's Kidney Early Evaluation Program with an estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2. RESULTS In the unadjusted analysis, higher PTH levels were associated with lower hemoglobin levels. However, after multivariable adjustment for age, race, gender, smoking status, education, cardiovascular disease, diabetes, hypertension, cancer, albuminuria, BMI, baseline eGFR, calcium, and phosphorus, the direction of association changed. As compared to the first PTH quintile, hemoglobin levels were 0.09 g/dl (95% CI: 0.01-0.18), 0.15 g/dl (95% CI: 0.07-0.24), 0.18 g/dl (95% CI: 0.09-0.26), and 0.13 g/dl (95% CI: 0.07-0.25) higher for the second, third, fourth, and fifth quintiles, respectively. Similarly, each standard deviation increase in natural log transformed PTH was associated with a 0.06 g/dl (95% CI: 0.03-0.09, p = 0.0003) increase in hemoglobin. However, a significant effect modification was seen for diabetes (p = 0.0003). Each standard deviation increase in natural log transformed PTH was associated with a 0.10 g/dl (95% CI: 0.054-0.138, p < 0.0001) increase in hemoglobin, while no association was seen among those without diabetes mellitus. CONCLUSION After multivariable adjustment, there was a small positive association between PTH and hemoglobin among diabetics but not among nondiabetics.
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Affiliation(s)
- Imran Memon
- Department of Internal Medicine and Pediatrics, University of Michigan School of Medicine, Ann Arbor, Mich., USA
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Braithwaite V, Bruggraber SFA, Prentice A. Intact fibroblast growth factor 23 and fragments in plasma from Gambian children. Osteoporos Int 2013; 24:1121-4. [PMID: 22648001 PMCID: PMC3572374 DOI: 10.1007/s00198-012-2029-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 04/25/2012] [Indexed: 12/23/2022]
Abstract
UNLABELLED Fibroblast growth factor 23 (FGF23) is grossly elevated in Gambian children with rickets and, at a lower prevalence, in those without bone deformities. We used western blotting to mimic the detection capabilities of the C-terminal FGF23 enzyme-linked immunosorbent assay (ELISA). Only intact FGF23 hormone was present in Gambian plasma samples from children with and without rickets. INTRODUCTION Elevated circulating FGF23 concentrations have been detected in plasma samples from Gambian children using the C-terminal Immutopics ELISA. The Immutopics ELISA detects both the intact FGF23 hormone and the C-terminal fragment. The aim of this study was to determine whether the elevated FGF23 concentrations as detected by the ELISA were predominantly due to a high proportion of intact FGF23 hormone and/or C-terminal FGF23 fragments. METHODS Stored, frozen plasma samples from previous studies of Gambian children with known concentrations of FGF23 as determined by C-terminal Immutopics ELISA assay, were selected for western blotting analysis: from children with rickets-like bone deformities (n = 4) and local controls (n = 4), with elevated >900 RU/ml (n = 2) and normal <30 RU/ml (n = 2; from each group). The anti-FGF23 polyclonal antibody that recognizes the C-terminal of FGF23 (as used in the Immutopics kit) was used as the primary antibody and the anti-IgG polyclonal antibody conjugated to horseradish peroxidase (HRP) was used as the secondary antibody. RESULTS Firstly, C-terminal FGF23 fragments, although detectable in standards from the Immutopics ELISA kit, were not in the Gambian plasma samples. Secondly, there was no difference in the size of FGF23 molecules present in plasma from children with rickets-like bone deformities and children from the local community. CONCLUSIONS Western blotting has provided evidence that elevated FGF23 concentrations, as determined by the C-terminal Immutopics ELISA, measured in Gambian children with and without rickets-like bone deformities was not caused by an increased proportion of circulating inactive C-terminal fragments.
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Affiliation(s)
- V Braithwaite
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge CB1 9NL, United Kingdom.
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Abstract
PURPOSE OF REVIEW Description of the recent advances on the regulation of phosphate metabolism, gene mutations, and new approaches to treatment in patients with hypophosphatemic rickets. RECENT FINDINGS Fibroblast growth factor 23 (FGF23) overproduction may be a primary cause of hypophosphatemic rickets. Inactivating mutations of phosphate-regulating gene with homologies to endopeptidases on the X chromosome, dentin matrix acidic phosphoprotein 1, and ectonucleotide pyrophosphatase/phosphodiesterase 1 are associated with X-linked hypophosphatemic rickets, autosomal recessive hypophosphatemic rickets 1, and autosomal recessive hypophosphatemic rickets 2, respectively. Activating mutations of FGF23 gene is the cause of autosomal dominant hypophosphatemic rickets. Iron deficiency may affect autosomal dominant hypophosphatemic rickets phenotype by regulating FGF23 production.Current treatment with activated vitamin D metabolites and oral inorganic phosphate salts may partially correct skeletal lesions and linear growth in patients with hypophosphatemic rickets. However, some patients have poor improvement by the current treatment. SUMMARY Identification of the causative mutation in patients with hypophosphatemic rickets may be useful to confirm the diagnosis and probably for prognosis. Inhibition of FGF23 overproduction by anti-FGF23 neutralizing antibodies could be a future approach for treatment of patients with FGF23-dependent hypophosphatemic rickets.
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Affiliation(s)
- Giampiero I Baroncelli
- Pediatric Unit I, Department of Obstetrics, Gynecology and Pediatrics, University-Hospital, Pisa, Italy.
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Pettifor JM, Thandrayen K. Hypophosphatemic rickets: unraveling the role of FGF23. Calcif Tissue Int 2012; 91:297-306. [PMID: 23001439 DOI: 10.1007/s00223-012-9651-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Accepted: 09/06/2012] [Indexed: 12/29/2022]
Abstract
The classification of the various forms of hypophosphatemic rickets has been rationalized by the discovery of the central role that fibroblast growth factor 23 (FGF23) plays in the pathogenesis of a number of genetic and acquired forms of the disease. Although the details of the interaction of FGF23 with other osteoblast/osteocyte-derived proteins remain unclear at present, the measurement of circulating levels of FGF23 appears to be a useful biochemical test in determining the various causes of hypophosphatemic rickets. Furthermore, animal studies suggest that agents interfering in the action of FGF23 might play important roles in the future management of the FGF23-mediated forms of rickets. Phase 1 and phase 2 trials in humans with X-linked hypophosphatemic rickets are currently under way.
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Affiliation(s)
- John M Pettifor
- MRC/Wits Developmental Pathways for Health Research Unit, Department of Paediatrics, Faculty of Health Sciences, University of the Witwatersrand, 7 York Rd, Parktown, Johannesburg 2193, South Africa.
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Braithwaite V, Prentice AM, Doherty C, Prentice A. FGF23 is correlated with iron status but not with inflammation and decreases after iron supplementation: a supplementation study. INTERNATIONAL JOURNAL OF PEDIATRIC ENDOCRINOLOGY 2012; 2012:27. [PMID: 23098062 PMCID: PMC3523041 DOI: 10.1186/1687-9856-2012-27] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 10/23/2012] [Indexed: 01/15/2023]
Abstract
Background Recent studies have described relationships between iron status and fibroblast growth factor-23 (FGF23) but the possible confounding effects of inflammation on iron status have not been considered. The aims of this study were a) to consider a relationship between FGF23 and inflammation b) to identify relationships between iron status and FGF23 whilst correcting for inflammation and c) to assess the relationship between changes in FGF23 and iron status after supplementation. Study design and methodology Blood samples from an iron supplementation study in children (n=79) were collected at baseline and after 3 months supplementation with iron sulphate. The children were from a rural Gambian population where rates of iron deficiency and infection/inflammation are high. This study identified cross-sectional and longitudinal relationships between FGF23, inflammation (C-reactive protein (CRP)) and iron status (ferritin, haemoglobin, and zinc protoporphyrin). CRP ≥ 5 mg/dL was used to indicate inflammation and FGF23 ≥ 125 RU/mL was considered elevated. Results FGF23 was not significantly correlated with CRP. At baseline, all markers of iron status were significantly correlated with FGF23. Ferritin was the strongest independent inverse predictor of FGF23 in subjects with and without elevated CRP (coefficient (SE)): All subjects=−0.57 (0.12), R2=22.3%, P≤0.0001; subjects with CRP < 5 mg/dL=−0.89 (0.14), R2=38.9%, P≤0.0001. FGF23 was elevated in 28% of children at baseline and 16% post supplementation (P=0.1). Improved iron status was associated with a decrease in FGF23 concentration in univariate (ferritin =−0.41 (0.11), R2=14.1%, P=0.0004; haemoglobin=−2.22 (0.64), R2=12.5%, P=0.0008; zinc protoporphyrin=1.12 (0.26), R2=18.6%, P≤0.0001) and multivariate analysis (R2=33.1%; ferritin=−0.36 (0.10), P=0.0007, haemoglobin = −1.83 (0.61), P=0.004, zinc protoporphyrin=0.62 (0.26), P=0.02). Conclusions Iron status rather than inflammation is a negative predictor of plasma FGF23 concentration. Improvements in iron status following iron supplementation are associated with a significant decrease in FGF23 concentration.
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Affiliation(s)
- Vickie Braithwaite
- MRC Human Nutrition Research, Elsie Widdowson Laboratory, Cambridge CB1 9NL, United Kingdom.
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