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Snyder PJ, Ellenberg SS, Cunningham GR, Matsumoto AM, Bhasin S, Barrett-Connor E, Gill TM, Farrar JT, Cella D, Rosen RC, Resnick SM, Swerdloff RS, Cauley JA, Cifelli D, Fluharty L, Pahor M, Ensrud KE, Lewis CE, Molitch ME, Crandall JP, Wang C, Budoff MJ, Wenger NK, Mohler ER, Bild DE, Cook NL, Keaveny TM, Kopperdahl DL, Lee D, Schwartz AV, Storer TW, Ershler WB, Roy CN, Raffel LJ, Romashkan S, Hadley E. The Testosterone Trials: Seven coordinated trials of testosterone treatment in elderly men. Clin Trials 2018; 11:362-375. [PMID: 24686158 DOI: 10.1177/1740774514524032] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background The prevalence of low testosterone levels in men increases with age, as does the prevalence of decreased mobility, sexual function, self-perceived vitality, cognitive abilities, bone mineral density, and glucose tolerance, and of increased anemia and coronary artery disease. Similar changes occur in men who have low serum testosterone concentrations due to known pituitary or testicular disease, and testosterone treatment improves the abnormalities. Prior studies of the effect of testosterone treatment in elderly men, however, have produced equivocal results. Purpose To describe a coordinated set of clinical trials designed to avoid the pitfalls of prior studies and to determine definitively whether testosterone treatment of elderly men with low testosterone is efficacious in improving symptoms and objective measures of age-associated conditions. Methods We present the scientific and clinical rationale for the decisions made in the design of this set of trials. Results We designed The Testosterone Trials as a coordinated set of seven trials to determine if testosterone treatment of elderly men with low serum testosterone concentrations and symptoms and objective evidence of impaired mobility and/or diminished libido and/or reduced vitality would be efficacious in improving mobility (Physical Function Trial), sexual function (Sexual Function Trial), fatigue (Vitality Trial), cognitive function (Cognitive Function Trial), hemoglobin (Anemia Trial), bone density (Bone Trial), and coronary artery plaque volume (Cardiovascular Trial). The scientific advantages of this coordination were common eligibility criteria, common approaches to treatment and monitoring, and the ability to pool safety data. The logistical advantages were a single steering committee, data coordinating center and data and safety monitoring board, the same clinical trial sites, and the possibility of men participating in multiple trials. The major consideration in participant selection was setting the eligibility criterion for serum testosterone low enough to ensure that the men were unequivocally testosterone deficient, but not so low as to preclude sufficient enrollment or eventual generalizability of the results. The major considerations in choosing primary outcomes for each trial were identifying those of the highest clinical importance and identifying the minimum clinically important differences between treatment arms for sample size estimation. Potential limitations Setting the serum testosterone concentration sufficiently low to ensure that most men would be unequivocally testosterone deficient, as well as many other entry criteria, resulted in screening approximately 30 men in person to randomize one participant. Conclusion Designing The Testosterone Trials as a coordinated set of seven trials afforded many important scientific and logistical advantages but required an intensive recruitment and screening effort.
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Westbrook RM, Yang HL, Langdon JM, Roy CN, Kim JA, Choudhury PP, Xue QL, di Francesco A, de Cabo R, Walston J. Aged interleukin-10tm1Cgn chronically inflamed mice have substantially reduced fat mass, metabolic rate, and adipokines. PLoS One 2017; 12:e0186811. [PMID: 29267271 PMCID: PMC5739384 DOI: 10.1371/journal.pone.0186811] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/06/2017] [Indexed: 12/11/2022] Open
Abstract
Interleukin 10tm1Cgn (IL 10tm) mice have been utilized as a model of chronic inflammation and declining health span because of their propensity to develop chronic activation in NFkB pathways, skeletal muscle and cardiac changes, and mitochondrial dysfunction. We hypothesized that older IL 10tm frail mice would have alterations similar to frail, older humans in measured parameters of glucose metabolism, oxygen consumption (VO2), respiratory quotient (RQ), spontaneous locomotor activity, body composition and plasma adipokine levels. To test this hypothesis, we investigated these metabolic parameters in cohorts of 3, 10, and 20 month old IL 10tm female mice and age and gender matched C57Bl/6 mice. Insulin sensitivity, glucose homeostasis, locomotor activity and RQ were not significantly altered between the two strains of mice. Interestingly, old IL 10tm mice had significantly decreased VO2 when normalized by lean mass, but not when normalized by fat mass or the lean/fat mass ratio. NMR based body composition analysis and dissection weights show that fat mass is decreased with age in IL 10tm mice compared to controls. Further, plasma adiponectin and leptin were also decreased in IL 10tm.These findings suggest that frailty observed in this mouse model of chronic inflammation may in part be driven by alterations in fat mass, hormone secretion and energy metabolism.
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Affiliation(s)
- Reyhan M Westbrook
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Huan Le Yang
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Jackie M Langdon
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Cindy N Roy
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Jin A Kim
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Parichoy P Choudhury
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, United States of America
| | - Qian-Li Xue
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Andrea di Francesco
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States of America
| | - Rafa de Cabo
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, United States of America
| | - Jeremy Walston
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
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Cohen HJ, Roy CN, Snyder PJ. Redefining Unexplained Anemia in Elderly-Reply. JAMA Intern Med 2017; 177:1395. [PMID: 28873192 DOI: 10.1001/jamainternmed.2017.2970] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Harvey Jay Cohen
- Center for the Study of Aging & Human Development, Duke University Medical Center, Durham, North Carolina
| | - Cindy N Roy
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Peter J Snyder
- Division of Hematology, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Roy CN, Snyder PJ, Stephens-Shields AJ, Artz AS, Bhasin S, Cohen HJ, Farrar JT, Gill TM, Zeldow B, Cella D, Barrett-Connor E, Cauley JA, Crandall JP, Cunningham GR, Ensrud KE, Lewis CE, Matsumoto AM, Molitch ME, Pahor M, Swerdloff RS, Cifelli D, Hou X, Resnick SM, Walston JD, Anton S, Basaria S, Diem SJ, Wang C, Schrier SL, Ellenberg SS. Association of Testosterone Levels With Anemia in Older Men: A Controlled Clinical Trial. JAMA Intern Med 2017; 177:480-490. [PMID: 28241237 PMCID: PMC5433757 DOI: 10.1001/jamainternmed.2016.9540] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
IMPORTANCE In one-third of older men with anemia, no recognized cause can be found. OBJECTIVE To determine if testosterone treatment of men 65 years or older with unequivocally low testosterone levels and unexplained anemia would increase their hemoglobin concentration. DESIGN, SETTING, AND PARTICIPANTS A double-blinded, placebo-controlled trial with treatment allocation by minimization using 788 men 65 years or older who have average testosterone levels of less than 275 ng/dL. Of 788 participants, 126 were anemic (hemoglobin ≤12.7 g/dL), 62 of whom had no known cause. The trial was conducted in 12 academic medical centers in the United States from June 2010 to June 2014. INTERVENTIONS Testosterone gel, the dose adjusted to maintain the testosterone levels normal for young men, or placebo gel for 12 months. MAIN OUTCOMES AND MEASURES The percent of men with unexplained anemia whose hemoglobin levels increased by 1.0 g/dL or more in response to testosterone compared with placebo. The statistical analysis was intent-to-treat by a logistic mixed effects model adjusted for balancing factors. RESULTS The men had a mean age of 74.8 years and body mass index (BMI) (calculated as weight in kilograms divided by height in meters squared) of 30.7; 84.9% were white. Testosterone treatment resulted in a greater percentage of men with unexplained anemia whose month 12 hemoglobin levels had increased by 1.0 g/dL or more over baseline (54%) than did placebo (15%) (adjusted OR, 31.5; 95% CI, 3.7-277.8; P = .002) and a greater percentage of men who at month 12 were no longer anemic (58.3%) compared with placebo (22.2%) (adjusted OR, 17.0; 95% CI, 2.8-104.0; P = .002). Testosterone treatment also resulted in a greater percentage of men with anemia of known cause whose month 12 hemoglobin levels had increased by 1.0 g/dL or more (52%) than did placebo (19%) (adjusted OR, 8.2; 95% CI, 2.1-31.9; P = .003). Testosterone treatment resulted in a hemoglobin concentration of more than 17.5 g/dL in 6 men who had not been anemic at baseline. CONCLUSIONS AND RELEVANCE Among older men with low testosterone levels, testosterone treatment significantly increased the hemoglobin levels of those with unexplained anemia as well as those with anemia from known causes. These increases may be of clinical value, as suggested by the magnitude of the changes and the correction of anemia in most men, but the overall health benefits remain to be established. Measurement of testosterone levels might be considered in men 65 years or older who have unexplained anemia and symptoms of low testosterone levels. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00799617.
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Affiliation(s)
- Cindy N Roy
- Divisions of Geriatric Medicine and Gerontology and Hematology, Johns Hopkins University, Baltimore, Maryland
| | - Peter J Snyder
- Division of Endocrinology, Diabetes, and Metabolism, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Alisa J Stephens-Shields
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Andrew S Artz
- Section of Hematology/Oncology, University of Chicago, Chicago, Illinois
| | - Shalender Bhasin
- Research Program in Men's Health: Aging and Metabolism, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Harvey J Cohen
- Duke University Medical Center, Center for the Study of Aging, Durham, North Carolina
| | - John T Farrar
- Center for Clinical Epidemiology & Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Thomas M Gill
- Division of Geriatric Medicine, Yale School of Medicine, New Haven, Connecticut
| | - Bret Zeldow
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - David Cella
- Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - Elizabeth Barrett-Connor
- Department of Internal Medicine and Division of Epidemiology, Department of Family Medicine and Public Health, University of California, San Diego School of Medicine, La Jolla
| | - Jane A Cauley
- Department of Epidemiology, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, Pennsylvania
| | - Jill P Crandall
- Divisions of Endocrinology and Geriatrics, Albert Einstein College of Medicine, Bronx, New York
| | - Glenn R Cunningham
- Departments of Medicine and Molecular & Cellular Biology, Division of Diabetes, Endocrinology and Metabolism, Baylor College of Medicine and Baylor St Luke's Medical Center, Houston, Texas
| | - Kristine E Ensrud
- Department of Medicine, Division of Epidemiology & Community Health, University of Minnesota, Minneapolis.,Minneapolis VA Health Care System, Minneapolis, Minnesota
| | - Cora E Lewis
- Division of Preventive Medicine, University of Alabama at Birmingham, Birmingham
| | - Alvin M Matsumoto
- Geriatric Research, Education, and Clinical Center, Department of Veterans Affairs Puget Sound Health Care System, and Division of Gerontology & Geriatric Medicine, Department of Internal Medicine, University of Washington School of Medicine, Seattle
| | - Mark E Molitch
- Division of Endocrinology, Metabolism and Molecular Medicine, Northwestern University, Feinberg School of Medicine, Chicago, Illinois
| | - Marco Pahor
- Department of Aging & Geriatric Research, University of Florida, Gainesville, Florida
| | - Ronald S Swerdloff
- Division of Endocrinology, Harbor-University of California at Los Angeles Medical Center and Los Angeles Biomedical Research Institute; Torrance
| | - Denise Cifelli
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Xiaoling Hou
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia
| | - Susan M Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, National Institutes of Health, Baltimore, Maryland
| | - Jeremy D Walston
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University, Baltimore, Maryland
| | - Stephen Anton
- Department of Aging & Geriatric Research, University of Florida, Gainesville, Florida
| | - Shehzad Basaria
- Research Program in Men's Health: Aging and Metabolism, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts
| | - Susan J Diem
- Department of Medicine, Division of Epidemiology & Community Health, University of Minnesota, Minneapolis
| | - Christina Wang
- Division of Endocrinology, Harbor-University of California at Los Angeles Medical Center and Los Angeles Biomedical Research Institute; Torrance
| | | | - Susan S Ellenberg
- Department of Biostatistics and Epidemiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia
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Atkinson MA, Kim JY, Roy CN, Warady BA, White CT, Furth SL. Hepcidin and risk of anemia in CKD: a cross-sectional and longitudinal analysis in the CKiD cohort. Pediatr Nephrol 2015; 30:635-43. [PMID: 25380788 PMCID: PMC4336204 DOI: 10.1007/s00467-014-2991-4] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/13/2014] [Accepted: 10/14/2014] [Indexed: 12/21/2022]
Abstract
BACKGROUND Hepcidin, a key iron regulatory protein, is elevated in patients with chronic kidney disease (CKD). Its role in the development and progression of the anemia of CKD in children remains poorly defined. METHODS Cross-sectional and longitudinal study in children aged 1-16 years with stage 2-4 CKD in the Chronic Kidney Disease in Children (CKiD) cohort (n = 133) with hepcidin measured at baseline and hemoglobin (HGB) measured annually at follow-up. Anemia was defined as HGB <5th percentile for age/sex OR treatment with an erythropoiesis-stimulating agent (ESA). RESULTS Hepcidin levels correlated negatively with glomerular filtration rate (GFR; r = -0.22, p = 0.01) and positively with ferritin (r = 0.67, p < 0.001). At the lower end of the GFR spectrum at baseline (10th percentile, 27.5 mL/min/1.73 m(2)), higher hepcidin was associated with a 0.87 g/dL decrease in HGB during follow-up (95 % CI -1.69, -0.05 g/dL, p = 0.038). At higher GFR percentiles there was no significant association between baseline hepcidin and HGB during follow-up. Among 90 non-anemic subjects at baseline, 23.3 % developed incident anemia. In subjects with GFR ≤ the median, a higher hepcidin level was associated with an increased risk of incident anemia (at the 10th percentile GFR, HR 3.471, 95 % CI 1.228, 9.810, p = 0.019; at the 25th percentile GFR, HR 2.641, 95 % CI 1.213, 5.750, p = 0.014; at the 50th percentile GFR, HR 1.953, 95 % CI 1.011, 3.772, p = 0.046). Among subjects with GFR at the 75th percentile or above, incrementally higher baseline hepcidin was not associated with increased anemia risk. CONCLUSIONS Higher hepcidin levels are associated with a decreased HGB and an increased risk of incident anemia, and this association is most significant among subjects with lower GFR.
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Affiliation(s)
- Meredith A. Atkinson
- Division of Pediatric Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Ji Young Kim
- The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Cindy N. Roy
- Divisions of Hematology and Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD
| | | | - Colin T. White
- British Columbia Children’s Hospital, Vancouver, BC, Canada
| | - Susan L. Furth
- The Children’s Hospital of Philadelphia, Philadelphia, PA
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Langdon JM, Barkataki S, Berger AE, Cheadle C, Xue QL, Sung V, Roy CN. RAP-011, an activin receptor ligand trap, increases hemoglobin concentration in hepcidin transgenic mice. Am J Hematol 2015; 90:8-14. [PMID: 25236856 DOI: 10.1002/ajh.23856] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 09/10/2014] [Accepted: 09/16/2014] [Indexed: 12/21/2022]
Abstract
Over expression of hepcidin antimicrobial peptide is a common feature of iron-restricted anemia in humans. We investigated the erythroid response to either erythropoietin or RAP-011, a "murinized" ortholog of sotatercept, in C57BL/6 mice and in hepcidin antimicrobial peptide 1 over expressing mice. Sotatercept, a soluble, activin receptor type IIA ligand trap, is currently being evaluated for the treatment of anemias associated with chronic renal disease, myelodysplastic syndrome, β-thalassemia, and Diamond Blackfan anemia and acts by inhibiting signaling downstream of activin and other Transforming Growth Factor-β superfamily members. We found that erythropoietin and RAP-011 increased hemoglobin concentration in C57BL/6 mice and in hepcidin antimicrobial peptide 1 over expressing mice. While erythropoietin treatment depleted splenic iron stores in C57BL/6 mice, RAP-011 treatment did not deplete splenic iron stores in mice of either genotype. Bone marrow erythroid progenitors from erythropoietin-treated mice exhibited iron-restricted erythropoiesis, as indicated by increased median fluorescence intensity of transferrin receptor immunostaining by flow cytometry. In contrast, RAP-011-treated mice did not exhibit the same degree of iron-restricted erythropoiesis. In conclusion, we have demonstrated that RAP-011 can improve hemoglobin concentration in hepcidin antimicrobial peptide 1 transgenic mice. Our data support the hypothesis that RAP-011 has unique biologic effects which prevent or circumvent depletion of mouse splenic iron stores. RAP-011 may, therefore, be an appropriate therapeutic for trials in human anemias characterized by increased expression of hepcidin antimicrobial peptide and iron-restricted erythropoiesis.
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Affiliation(s)
- Jacqueline M. Langdon
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Sangjucta Barkataki
- Lowe Family Genomics Core; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Alan E. Berger
- Lowe Family Genomics Core; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Chris Cheadle
- Lowe Family Genomics Core; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Qian-Li Xue
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Victoria Sung
- Translational Development; Celgene Corporation; San Francisco CA
| | - Cindy N. Roy
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
- Division of Hematology; Johns Hopkins School of Medicine; Baltimore Maryland
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Price E, Artz AS, Barnhart H, Sapp S, Chelune G, Ershler WB, Walston JD, Gordeuk VR, Berger NA, Reuben D, Prchal J, Rao SV, Roy CN, Supiano MA, Schrier SL, Cohen HJ. A prospective randomized wait list control trial of intravenous iron sucrose in older adults with unexplained anemia and serum ferritin 20-200 ng/mL. Blood Cells Mol Dis 2014; 53:221-30. [PMID: 25065855 DOI: 10.1016/j.bcmd.2014.06.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 06/30/2014] [Indexed: 10/25/2022]
Abstract
Anemia is common in older persons and is associated with substantial morbidity and mortality. One third of anemic older adults have unexplained anemia of the elderly (UAE). We carried out a randomized, wait list control trial in outpatients with UAE and serum ferritin levels between 20 and 200 ng/mL. Intravenous iron sucrose was given as a 200-mg weekly dose for 5 weeks either immediately after enrollment (immediate intervention group) or following a 12-week wait list period (wait list control group). The primary outcome measure was changed in 6-minute walk test (6MWT) distances from baseline to 12 weeks between the two groups. Hematologic, physical, cognitive, and quality of life parameters were also assessed. The study was terminated early after 19 subjects enrolled. The distance walked in the 6MWT increased a mean 8.05±55.48 m in the immediate intervention group and decreased a mean 11.45±49.46 m in the wait list control group (p=0.443). The hemoglobin increased a mean 0.39±0.46 g/dL in the immediate intervention group and declined a mean 0.39±0.85 g/dL in the wait list control group (p=0.026). Thus, a subgroup of adults with UAE may respond to intravenous iron. Enrollment of subjects into this type of study remains challenging.
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Affiliation(s)
- Elizabeth Price
- Division of Pulmonary and Critical Care Medicine, 300 Pasteur Drive, Room H3143, MC 5236 Stanford, CA 94305, USA.
| | - Andrew S Artz
- University of Chicago, 5841 S Maryland Ave., Chicago, IL 60637, USA.
| | - Huiman Barnhart
- Duke Clinical Research Institute, PO Box 17969, Durham, NC 27715, USA.
| | - Shelly Sapp
- Duke University Medical Center, Durham, NC 27710, USA.
| | - Gordon Chelune
- Center for Alzheimer's Care, Imaging and Research, University of Utah, Dept. of Neurology, 650 Komas Drive, Salt Lake City, UT 84108, USA.
| | - William B Ershler
- Institute for Advanced Studies in Aging, 6400 Arlington Blvd., Falls Church, VA 22042, USA.
| | - Jeremy D Walston
- Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
| | - Victor R Gordeuk
- University of Illinois at Chicago, Clinical Science North Bldg., 820S Wood St., Chicago, IL 60612, USA.
| | - Nathan A Berger
- Case Western Reserve University, 10900 Euclid Ave., Cleveland, OH 44106, USA.
| | - David Reuben
- University of California, Los Angeles Medical Center, 10945 Le Conte Ave., Los Angeles, CA 90095, USA.
| | - Josef Prchal
- University of Utah School of Medicine, 30 North 1900 East, Salt Lake City, UT 84132, USA.
| | - Sunil V Rao
- Duke University Medical Center, Durham VA Medical Center, 508 Fulton Street, Durham, NC 27705, USA.
| | - Cindy N Roy
- Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
| | - Mark A Supiano
- University of Utah School of Medicine, 30 North 1900 East, Salt Lake City, UT 84132, USA.
| | | | - Harvey Jay Cohen
- Duke University Medical Center, Center for the Study of Aging, Box 3003, Durham, NC 27710, USA.
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Artz AS, Xue QL, Wickrema A, Hesdorffer C, Ferrucci L, Langdon JM, Walston JD, Roy CN. Unexplained anaemia in the elderly is characterised by features of low grade inflammation. Br J Haematol 2014; 167:286-9. [PMID: 24935746 DOI: 10.1111/bjh.12984] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Andrew S Artz
- Section of Hematology/Oncology, University of Chicago, Chicago, IL, USA
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Langdon JM, Yates SC, Femnou LK, McCranor BJ, Cheadle C, Xue QL, Vaulont S, Civin CI, Walston JD, Roy CN. Hepcidin-dependent and hepcidin-independent regulation of erythropoiesis in a mouse model of anemia of chronic inflammation. Am J Hematol 2014; 89:470-9. [PMID: 24415655 DOI: 10.1002/ajh.23670] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 01/02/2014] [Accepted: 01/08/2014] [Indexed: 12/21/2022]
Abstract
Increased hepcidin antimicrobial peptide correlates with hypoferremia and anemia in various disease states, but its requirement for anemia of inflammation has not been adequately demonstrated. Anemia of inflammation is usually described as normocytic and normochromic, while diseases associated with over expression of hepcidin, alone, are often microcytic and hypochromic. These differences in erythrocyte parameters suggest anemia in many inflammatory states may not be fully explained by hepcidin-mediated iron sequestration. We used turpentine-induced sterile abscesses to model chronic inflammation in mice with targeted disruption of Hepcidin 1 [Hepc1 (-/-)] or its positive regulator, Interleukin-6 [IL-6 (-/-)], to determine whether these genes are required for features characteristic of anemia of inflammation. Although hemoglobin levels did not decline in Hepc1 (-/-) mice with sterile abscesses, erythrocyte numbers were significantly reduced compared to untreated Hepc1 (-/-) mice. In contrast, both hemoglobin concentration and erythrocyte number declined significantly in wild type and IL-6 (-/-) mice with sterile abscesses. Both Hepc1 (-/-) and IL-6 (-/-) mice had increased erythrocyte mean cell volume and mean cell hemoglobin following sterile abscesses, while wild types had no change. Thus, IL-6 (-/-) mice with sterile abscesses exhibit an intermediate phenotype between wild type and Hepc1 (-/-). Our results demonstrate the requirement of Hepc1 for the development of anemia in this rodent model. Simultaneously, our results demonstrate hepcidin-independent effects of inflammation on the suppression of erythropoiesis. Our results suggest chronic anemia associated with inflammation may benefit from interventions protecting erythrocyte number in addition to anti-hepcidin interventions aimed at enhancing iron availability.
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Affiliation(s)
- Jacqueline M. Langdon
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Saiah C. Yates
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Laurette K. Femnou
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Bryan J. McCranor
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Chris Cheadle
- Lowe Family Genomics Core; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Qian-Li Xue
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
- Department of Epidemiology; Johns Hopkins Bloomberg School of Public Health; Baltimore Maryland
| | - Sophie Vaulont
- Institut Cochin, Institut National de la Santé et de la Recherche Medicale U1016; Paris France
| | - Curt I. Civin
- Center for Stem Cell Biology and Regenerative Medicine; Department of Pediatrics; University of Maryland; Baltimore Maryland
- Center for Stem Cell Biology and Regenerative Medicine; Department of Physiology; University of Maryland; Baltimore Maryland
| | - Jeremy D. Walston
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
| | - Cindy N. Roy
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University School of Medicine; Baltimore Maryland
- Division of Hematology; Johns Hopkins University School of Medicine; Baltimore Maryland
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McCranor BJ, Kim MJ, Cruz NM, Xue QL, Berger AE, Walston JD, Civin CI, Roy CN. Corrigendum to “Interleukin-6 Directly Impairs the Erythroid Development of Human TF-1 Erythroleukemic Cells” [Blood Cells Mol. Dis. 52 (2) (2014)]. Blood Cells Mol Dis 2014. [DOI: 10.1016/j.bcmd.2014.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Atkinson MA, Melamed ML, Kumar J, Roy CN, Miller ER, Furth SL, Fadrowski JJ. Vitamin D, race, and risk for anemia in children. J Pediatr 2014; 164:153-158.e1. [PMID: 24112861 PMCID: PMC3872204 DOI: 10.1016/j.jpeds.2013.08.060] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2013] [Revised: 07/24/2013] [Accepted: 08/26/2013] [Indexed: 12/22/2022]
Abstract
OBJECTIVE To examine the association between 25-hydroxyvitamin D [25(OH)D] deficiency and anemia in a cohort of otherwise-healthy children and to determine whether race modifies the association between 25(OH)D status and hemoglobin (Hgb). STUDY DESIGN Cross-sectional study of 10,410 children and adolescents ages 1-21 years from the 2001-2006 National Health and Nutrition Examination Survey. Anemia was defined as Hgb less than the 5th percentile for age and sex based on National Health and Nutrition Examination Survey III (1988-1994) data. RESULTS Lower 25(OH)D levels were associated with increased risk for anemia; <30 ng/mL, adjusted OR 1.93, 95% CI 1.21-3.08, P = .006, and <20 ng/mL, OR 1.47, 95% CI 1.14-1.89, P = .004. In linear regression, small but significant increases in Hgb were noted in the upper quartiles of 25(OH)D compared with the lowest quartile (<20 ng/mL) in the full cohort. Results of race-stratified linear regression by 25(OH)D quartile in white children were similar to those observed in the full cohort, but in black children, an increase in Hgb in the upper 25(OH)D quartiles was only apparent compared with the lowest black race-specific quartile (<12 ng/mL). CONCLUSION 25(OH)D deficiency is associated with increased risk of anemia in healthy US children, but the 25(OH)D threshold levels for lower Hgb are lower in black children in comparison with white children.
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Affiliation(s)
- Meredith A. Atkinson
- Division of Pediatric Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Michal L. Melamed
- Departments of Medicine and Epidemiology & Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - Juhi Kumar
- Division of Pediatric Nephrology, Weill Cornell Medical College, New York, NY
| | - Cindy N. Roy
- Divisions of Hematology and Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Edgar R. Miller
- Welch Center for Prevention, Epidemiology, and Clinical Research, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Susan L. Furth
- The Children’s Hospital of Philadelphia, Philadelphia, PA
| | - Jeffrey J. Fadrowski
- Division of Pediatric Nephrology, Johns Hopkins University School of Medicine, Baltimore, MD
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McCranor BJ, Langdon JM, Prince OD, Femnou LK, Berger AE, Cheadle C, Civin CI, Kim A, Rivera S, Ganz T, Vaulont S, Xue QL, Walston JD, Roy CN. Investigation of the role of interleukin-6 and hepcidin antimicrobial peptide in the development of anemia with age. Haematologica 2013; 98:1633-40. [PMID: 23996485 DOI: 10.3324/haematol.2013.087114] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Anemia is common in older adults and associated with adverse health outcomes in epidemiological studies. A thorough understanding of the complex pathophysiological mechanisms driving anemia in the elderly is lacking; but inflammation, iron restriction, and impaired erythroid maturation are thought to influence the phenotype. We hypothesized that interleukin-6 contributes to this anemia, given its pro-inflammatory activities, its ability to induce hepcidin antimicrobial peptide, and its negative impact on several tissues in older adults. We tested this hypothesis by comparing changes in indices of inflammation, iron metabolism and erythropoiesis in aged C57BL/6 mice to aged mice with targeted deletions of interleukin-6 or hepcidin antimicrobial peptide. Circulating neutrophil and monocyte numbers and inflammatory cytokines increased with age. Decline in hemoglobin concentration and red blood cell number indicated that C57BL/6, interleukin-6 knockout mice, and hepcidin antimicrobial peptide knockout mice all demonstrated impaired erythropoiesis by 24 months. However, the interleukin-6 knock out genotype and the hepcidin antimicrobial peptide knock out genotype resulted in improved erythropoiesis in aged mice. Increased erythropoietic activity in the spleen suggested that the erythroid compartment was stressed in aged C57BL/6 mice compared to aged interleukin-6 knockout mice. Our data suggest C57BL/6 mice are an appropriate mammalian model for the study of anemia with age. Furthermore, although interleukin-6 and hepcidin antimicrobial peptide are not required, they can participate in the development of anemia in aging mice, and could be targeted, pre-clinically, with existing interventions to determine the feasibility of such agents for the treatment of anemia in older adults.
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Chisti MJ, Saha S, Roy CN, Ahmed T, Faruque ASG, Salam MA, Islam S. Predictors of mortality in infants with sclerema presenting to the Centre for Diarrhoeal Disease, Dhaka. ACTA ACUST UNITED AC 2013; 29:45-50. [PMID: 19222934 DOI: 10.1179/146532809x402024] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- M J Chisti
- International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka 1212, Bangladesh.
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14
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Guo W, Bachman E, Li M, Roy CN, Blusztajn J, Wong S, Chan SY, Serra C, Jasuja R, Travison TG, Muckenthaler MU, Nemeth E, Bhasin S. Testosterone administration inhibits hepcidin transcription and is associated with increased iron incorporation into red blood cells. Aging Cell 2013; 12:280-91. [PMID: 23399021 DOI: 10.1111/acel.12052] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/02/2013] [Indexed: 01/01/2023] Open
Abstract
Testosterone administration increases hemoglobin levels and has been used to treat anemia of chronic disease. Erythrocytosis is the most frequent adverse event associated with testosterone therapy of hypogonadal men, especially older men. However, the mechanisms by which testosterone increases hemoglobin remain unknown. Testosterone administration in male and female mice was associated with a greater increase in hemoglobin and hematocrit, reticulocyte count, reticulocyte hemoglobin concentration, and serum iron and transferrin saturation than placebo. Testosterone downregulated hepatic hepcidin mRNA expression, upregulated renal erythropoietin mRNA expression, and increased erythropoietin levels. Testosterone-induced suppression of hepcidin expression was independent of its effects on erythropoietin or hypoxia-sensing mechanisms. Transgenic mice with liver-specific constitutive hepcidin over-expression failed to exhibit the expected increase in hemoglobin in response to testosterone administration. Testosterone upregulated splenic ferroportin expression and reduced iron retention in spleen. After intravenous administration of transferrin-bound (58) Fe, the amount of (58) Fe incorporated into red blood cells was significantly greater in testosterone-treated mice than in placebo-treated mice. Serum from testosterone-treated mice stimulated hemoglobin synthesis in K562 erythroleukemia cells more than that from vehicle-treated mice. Testosterone administration promoted the association of androgen receptor (AR) with Smad1 and Smad4 to reduce their binding to bone morphogenetic protein (BMP)-response elements in hepcidin promoter in the liver. Ectopic expression of AR in hepatocytes suppressed hepcidin transcription; this effect was blocked dose-dependently by AR antagonist flutamide. Testosterone did not affect hepcidin mRNA stability. In conclusion, testosterone inhibits hepcidin transcription through its interaction with BMP/Smad signaling. Testosterone administration is associated with increased iron incorporation into red blood cells.
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Affiliation(s)
- Wen Guo
- Section of Endocrinology, Diabetes, and Nutrition; Boston University School of Medicine; Boston Claude D. Pepper Older Americans Independence Center; Boston Medical Center; Boston; MA; 02118; USA
| | - Eric Bachman
- Section of Endocrinology, Diabetes, and Nutrition; Boston University School of Medicine; Boston Claude D. Pepper Older Americans Independence Center; Boston Medical Center; Boston; MA; 02118; USA
| | - Michelle Li
- Section of Endocrinology, Diabetes, and Nutrition; Boston University School of Medicine; Boston Claude D. Pepper Older Americans Independence Center; Boston Medical Center; Boston; MA; 02118; USA
| | - Cindy N. Roy
- Division of Geriatric Medicine and Gerontology; Johns Hopkins University; Room 2A.44, 5501 Hopkins Bayview Circle; Baltimore; MD; 21224; USA
| | - Jerzy Blusztajn
- Woods Hole Oceanographic Institution; 266 Woods Hole Rd. MS# 25; Woods Hole; MA; 02543-1050; USA
| | - Siu Wong
- Section of Endocrinology, Diabetes, and Nutrition; Boston University School of Medicine; Boston Claude D. Pepper Older Americans Independence Center; Boston Medical Center; Boston; MA; 02118; USA
| | - Stephen Y. Chan
- Division of Cardiovascular Medicine; Department of Medicine; Brigham and Women's Hospital; Boston; MA; 02115; USA
| | - Carlo Serra
- Section of Endocrinology, Diabetes, and Nutrition; Boston University School of Medicine; Boston Claude D. Pepper Older Americans Independence Center; Boston Medical Center; Boston; MA; 02118; USA
| | - Ravi Jasuja
- Section of Endocrinology, Diabetes, and Nutrition; Boston University School of Medicine; Boston Claude D. Pepper Older Americans Independence Center; Boston Medical Center; Boston; MA; 02118; USA
| | - Thomas G. Travison
- Section of Endocrinology, Diabetes, and Nutrition; Boston University School of Medicine; Boston Claude D. Pepper Older Americans Independence Center; Boston Medical Center; Boston; MA; 02118; USA
| | - Martina U. Muckenthaler
- Department of Molecular Medicine; University of Heidelberg; Otto-Meyerhof-Zentrum; Im Neuenheimer Feld 350; 69120; Heidelberg; Germany
| | - Elizabeta Nemeth
- Center for Iron Disorders; Division of Pulmonary and Critical Care Medicine; David Geffen School of Medicine at UCLA; CHS 52-239, 10833 Le Conte Ave; Los Angeles; CA; 90095-1690; USA
| | - Shalender Bhasin
- Section of Endocrinology, Diabetes, and Nutrition; Boston University School of Medicine; Boston Claude D. Pepper Older Americans Independence Center; Boston Medical Center; Boston; MA; 02118; USA
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15
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Prince OD, Langdon JM, Layman AJ, Prince IC, Sabogal M, Mak HH, Berger AE, Cheadle C, Chrest FJ, Yu Q, Andrews NC, Xue QL, Civin CI, Walston JD, Roy CN. Late stage erythroid precursor production is impaired in mice with chronic inflammation. Haematologica 2012; 97:1648-56. [PMID: 22581006 DOI: 10.3324/haematol.2011.053397] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND We and others have shown previously that over-expression of hepcidin antimicrobial peptide, independently of inflammation, induces several features of anemia of inflammation and chronic disease, including hypoferremia, sequestration of iron stores and iron-restricted erythropoiesis. Because the iron-restricted erythropoiesis evident in hepcidin transgenic mice differs from the normocytic, normochromic anemia most often observed in anemia of inflammation, we tested the hypothesis that chronic inflammation may contribute additional features to anemia of inflammation which continue to impair erythropoiesis following the acute phase of inflammation in which hepcidin is active. DESIGN AND METHODS We compared erythropoiesis and iron handling in mice with turpentine-induced sterile abscesses with erythropoiesis and iron handling in hepcidin transgenic mice. We compared erythrocyte indices, expression of genes in the hepcidin regulatory pathway, tissue iron distribution, expression of heme and iron transport genes in splenic macrophages, the phenotype of erythroid maturation and chloromethyl dichlorodihydrofluorescein diacetate, acetyl ester fluorescence. RESULTS Mice with sterile abscesses exhibited an intense, acute inflammatory phase followed by a mild to moderate chronic inflammatory phase. We found that erythrocytes in mice with sterile abscesses were normocytic and normochromic in contrast to those in hepcidin transgenic mice. We also observed that although hypoferremia resolved in the late phases of inflammation, erythropoiesis remained suppressed, with evidence of inefficient maturation of erythroid precursors in the bone marrow of mice with sterile abscesses. Finally, we observed increased oxidative stress in erythroid progenitors and circulating erythrocytes of mice with sterile abscesses which was not evident in hepcidin transgenic mice. CONCLUSIONS Our results suggest that chronic inflammation inhibits late stages of erythroid production in the turpentine-induced sterile abscess model and induces features of impaired erythropoiesis which are distinct from those in hepcidin transgenic mice.
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Affiliation(s)
- Olivier D Prince
- Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
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16
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Chou DB, Sworder B, Bouladoux N, Roy CN, Uchida AM, Grigg M, Robey PG, Belkaid Y. Stromal-derived IL-6 alters the balance of myeloerythroid progenitors during Toxoplasma gondii infection. J Leukoc Biol 2012; 92:123-31. [PMID: 22493080 DOI: 10.1189/jlb.1011527] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Inflammation alters hematopoiesis, often by decreasing erythropoiesis and enhancing myeloid output. The mechanisms behind these changes and how the BM stroma contributes to this process are active areas of research. In this study, we examine these questions in the setting of murine Toxoplasma gondii infection. Our data reveal that infection alters early myeloerythroid differentiation, blocking erythroid development beyond the Pre MegE stage, while expanding the GMP population. IL-6 was found to be a critical mediator of these differences, independent of hepcidin-induced iron restriction. Comparing the BM with the spleen showed that the hematopoietic response was driven by the local microenvironment, and BM chimeras demonstrated that radioresistant cells were the relevant source of IL-6 in vivo. Finally, direct ex vivo sorting revealed that VCAM(+)CD146(lo) BM stromal fibroblasts significantly increase IL-6 secretion after infection. These data suggest that BMSCs regulate the hematopoietic changes during inflammation via IL-6.
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Affiliation(s)
- David B Chou
- Mucosal Immunology, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
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17
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Roy CN, Semba RD, Sun K, Bandinelli S, Varadhan R, Patel KV, Guralnik JM, Ferrucci L. Circulating selenium and carboxymethyl-lysine, an advanced glycation endproduct, are independent predictors of anemia in older community-dwelling adults. Nutrition 2012; 28:762-6. [PMID: 22325035 DOI: 10.1016/j.nut.2011.11.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Revised: 11/03/2011] [Accepted: 11/04/2011] [Indexed: 01/14/2023]
Abstract
OBJECTIVE To assess whether selenium and carboxymethyl-lysine (CML), two biomarkers of oxidative stress, are independent predictors of anemia in older community-dwelling adults. METHODS Plasma levels of selenium, CML, folate, vitamin B12, and testosterone and markers of iron status and inflammation were measured at baseline in 1036 adults at least 65 y old in the Invecchiare in Chianti Study, a population-based cohort study of aging in Tuscany, Italy, and examined in relation to prevalent anemia and incident anemia over 6 y of follow-up. RESULTS At enrollment, 11.6% of participants were anemic. Of 472 participants who were non-anemic at enrollment, 72 (15.3%) developed anemia within 6 y of follow-up. At enrollment, plasma CML in the highest quartile (>425 ng/mL) and plasma selenium in the lowest quartile (<66.6 μg/L) predicted incident anemia (hazard ratio 1.67, 95% confidence interval 1.07-2.59, P = 0.02; hazard ratio 1.55, 95% confidence interval 1.01-2.38, P = 0.05, respectively) in a multivariate Cox proportional hazards model that adjusted for age, education, body mass index, cognition, inflammation, red blood cell distribution width, ferritin, vitamin B12, testosterone, and chronic diseases. CONCLUSION Elevated plasma CML and low plasma selenium are long-term independent predictors of anemia in older community-dwelling adults. These findings support the idea that oxidative stress contributes to the development of anemia.
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Affiliation(s)
- Cindy N Roy
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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18
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Abstract
Developed countries, such as the United Kingdom, are experiencing a change in demographics resulting in the largest proportion of adults over 65 years of age that our health systems have ever experienced. As such, haematologists must be prepared to evaluate and treat anaemia in a more complicated patient population, but sufficient evidence-based guidelines are lacking. Critical next steps that must be taken to ensure the best care of this population include the determination of appropriate haemoglobin concentrations for older adults in light of age, gender, race, and comorbidities; the development of interventional trials that address physical performance outcomes in addition to haemoglobin targets; and translational studies which address the molecular pathogenesis of anaemia in older adults with the most advanced scientific approaches.
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Affiliation(s)
- Akil A. Merchant
- Division of Hematology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Cindy N. Roy
- Division of Hematology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
- Division of Geriatric Medicine and Gerontology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
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19
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Abstract
Although anemia is regarded as a relatively common occurrence in older adults, the vigor with which the medical community should intervene to correct this common problem is disputed. Epidemiologic data clearly correlate anemia with functional decline, disability, and mortality. Anemia may contribute to functional decline by restricting oxygen delivery to muscle, or to cognitive decline by restricting oxygen delivery to the brain. On the other hand, the erythron may be a separate target of the same biologic mediators that influence deterioration of physiologic systems that contribute to weakness, functional and cognitive decline, and mortality. Clinical trials aimed at treating anemia in older adults could assess whether physical performance is improved or whether mortality risk declines with improved hemoglobin, but sufficient evidence from such trials is currently lacking. With few guidelines regarding treatment of older adults and significant risk for adverse events associated with transfusion and erythroid stimulating agents, anemia often goes untreated or ignored in geriatric clinics. This article reviews the problem of anemia in older adults, with a particular emphasis on the frail elderly. The gaps in the evidence base for the treatment of anemia in older adults are reviewed and the options for advancing the field are assessed.
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Affiliation(s)
- Cindy N Roy
- Division of Geriatric Medicine and Gerontology, Department of Medicine, Johns Hopkins University School of Medicine, 5501 Hopkins Bayview Circle, Baltimore, MD 21224, USA.
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20
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Gardenghi S, Ramos P, Marongiu MF, Melchiori L, Breda L, Guy E, Muirhead K, Rao N, Roy CN, Andrews NC, Nemeth E, Follenzi A, An X, Mohandas N, Ginzburg Y, Rachmilewitz EA, Giardina PJ, Grady RW, Rivella S. Hepcidin as a therapeutic tool to limit iron overload and improve anemia in β-thalassemic mice. J Clin Invest 2010; 120:4466-77. [PMID: 21099112 DOI: 10.1172/jci41717] [Citation(s) in RCA: 183] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2009] [Accepted: 09/29/2010] [Indexed: 12/11/2022] Open
Abstract
Excessive iron absorption is one of the main features of β-thalassemia and can lead to severe morbidity and mortality. Serial analyses of β-thalassemic mice indicate that while hemoglobin levels decrease over time, the concentration of iron in the liver, spleen, and kidneys markedly increases. Iron overload is associated with low levels of hepcidin, a peptide that regulates iron metabolism by triggering degradation of ferroportin, an iron-transport protein localized on absorptive enterocytes as well as hepatocytes and macrophages. Patients with β-thalassemia also have low hepcidin levels. These observations led us to hypothesize that more iron is absorbed in β-thalassemia than is required for erythropoiesis and that increasing the concentration of hepcidin in the body of such patients might be therapeutic, limiting iron overload. Here we demonstrate that a moderate increase in expression of hepcidin in β-thalassemic mice limits iron overload, decreases formation of insoluble membrane-bound globins and reactive oxygen species, and improves anemia. Mice with increased hepcidin expression also demonstrated an increase in the lifespan of their red cells, reversal of ineffective erythropoiesis and splenomegaly, and an increase in total hemoglobin levels. These data led us to suggest that therapeutics that could increase hepcidin levels or act as hepcidin agonists might help treat the abnormal iron absorption in individuals with β-thalassemia and related disorders.
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Semba RD, Patel KV, Ferrucci L, Sun K, Roy CN, Guralnik JM, Fried LP. Serum antioxidants and inflammation predict red cell distribution width in older women: the Women's Health and Aging Study I. Clin Nutr 2010; 29:600-4. [PMID: 20334961 DOI: 10.1016/j.clnu.2010.03.001] [Citation(s) in RCA: 229] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 02/11/2010] [Accepted: 03/01/2010] [Indexed: 10/19/2022]
Abstract
BACKGROUND & AIMS Red cell distribution width (RDW), a measure of heterogeneity in the size of circulating erythrocytes, is associated with some chronic diseases and predicts mortality. Although oxidative damage and inflammation have been theorized to affect RDW, the relationships of antioxidants and inflammation with RDW have not been well characterized. The aims were to determine whether total serum carotenoids, α-tocopherol, selenium, protein carbonyls, and interleukin-6 (IL-6) are associated with RDW and predict RDW over time. METHODS RDW was measured at baseline, 12 months, and 24 months follow-up in 786 moderately to severely disabled community-dwelling women, aged ≥65 years, in the Women's Health and Aging Study I in Baltimore, Maryland. RESULTS Selenium was significantly associated with RDW at baseline and predicted RDW over two years' follow-up in separate multivariate mixed-effects models that adjusted for other covariates. As expected, the addition of IL-6 to the models attenuated the association of serum selenium with RDW, as low antioxidant levels are known to upregulate IL-6. Total carotenoids were associated with RDW at baseline and one year follow-up. Protein carbonyls and α-tocopherol were not significantly associated with RDW. CONCLUSION Serum selenium is an independent predictor of RDW and may potentially mediate effects on RDW through IL-6.
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Affiliation(s)
- Richard D Semba
- Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States.
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22
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Abstract
Inflammation arising from various etiologies, including infection, autoimmune disorders, chronic diseases, and aging, can promote anemia. The anemia of inflammation (AI) is most often normocytic and normochromic and is usually mild. Characteristic changes in systemic iron handling, erythrocyte production, and erythrocyte life span all contribute to AI. The preferred treatment is directed at the underlying disease. However, when the inflammatory insult is intractable, or the cause has not been diagnosed, there are limited options for treatment of AI. Because anemia is a comorbid condition that is associated with poor outcomes in various chronic disease states, understanding its pathogenesis and developing new tools for its treatment should remain a priority. Hepcidin antimicrobial peptide has taken center stage in recent years as a potent modulator of iron availability. As the technology for quantitative hepcidin analysis improves, hepcidin's role in various disease states is also being revealed. Recent insights concerning the regulatory pathways that modify hepcidin expression have identified novel targets for drug development. As the field advances with such therapeutics, the analysis of the impact of normalized hemoglobin on disease outcomes will confirm whether anemia is a reversible independent contributor to the morbidity and mortality associated with inflammatory diseases.
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Affiliation(s)
- Cindy N Roy
- Division of Geriatric Medicine and Gerontology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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23
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Abstract
The anemia of inflammation is an acquired disorder affecting patients with a variety of medical conditions, and it is characterized by changes in iron homeostasis and erythropoiesis. Mounting evidence suggests that hepcidin antimicrobial peptide plays a primary role in the pathogenesis of the anemia of inflammation. To evaluate which features of this anemia can be attributed to hepcidin, we have generated mice carrying a tetracycline-regulated hepcidin transgene. Expression of the hepcidin transgene resulted in down-regulation of endogenous hepcidin mRNA. The transgenic mice developed a mild-to-moderate anemia associated with iron deficiency and iron-restricted erythropoiesis. Similar to the anemia of inflammation, iron accumulated in tissue macrophages, whereas a relative paucity of iron was found in the liver. Circulating erythrocytes in transgenic animals had normal survival rates, but transgenic animals had an impaired response to erythropoietin. Thus, hepcidin transgenic mice recapitulate each of the key features of anemia of inflammation in human patients and serve as a useful model of this prevalent disorder.
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Affiliation(s)
- Cindy N Roy
- Division of Hematology/Oncology, Chiuldren's Hospital Boston, Boston, MA, USA.
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Abstract
Iron is an essential element that is toxic when it accumulates in excess. Intricate regulatory mechanisms have evolved to maintain iron homeostasis within cells and between different tissues of complex organisms. This review discusses the proteins involved in iron transport and storage and their regulation in health and disease.
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Affiliation(s)
- Adriana Donovan
- Children's Hospital Boston, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
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25
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Abstract
PURPOSE OF REVIEW The anemia of inflammation has been associated for nearly two decades with elevated cytokine levels, but the primary mediator of this condition was unknown. Recently hepcidin antimicrobial peptide has emerged as the hormone that links the type II acute phase response to iron handling and erythropoiesis. RECENT FINDINGS Hepcidin antimicrobial peptide likely modulates iron transport from macrophages and enterocytes to red blood cell precursors as a consequence of its interaction with SLC40A1/ferroportin, the only known transporter that facilitates iron egress. Insights into the regulation of hepcidin antimicrobial peptide expression by known iron metabolic proteins such as HFE, hemojuvelin, and transferrin receptor 2 are expanding the understanding of the genetic circuitry that controls iron absorption and utilization. SUMMARY Increasingly, experiments suggest the hepatocyte is not just the iron storage depot but is the 'command central' for the maintenance of iron homeostasis. It receives multiple signals related to iron balance and responds via transcriptional control of hepcidin antimicrobial peptide.
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Roy CN, Custodio AO, de Graaf J, Schneider S, Akpan I, Montross LK, Sanchez M, Gaudino A, Hentze MW, Andrews NC, Muckenthaler MU. An Hfe-dependent pathway mediates hyposideremia in response to lipopolysaccharide-induced inflammation in mice. Nat Genet 2004; 36:481-5. [PMID: 15098034 DOI: 10.1038/ng1350] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Accepted: 03/19/2004] [Indexed: 01/04/2023]
Abstract
Inflammation influences iron balance in the whole organism. A common clinical manifestation of these changes is anemia of chronic disease (ACD; also called anemia of inflammation). Inflammation reduces duodenal iron absorption and increases macrophage iron retention, resulting in low serum iron concentrations (hyposideremia). Despite the protection hyposideremia provides against proliferating microorganisms, this 'iron withholding' reduces the iron available to maturing red blood cells and eventually contributes to the development of anemia. Hepcidin antimicrobial peptide (Hamp) is a hepatic defensin-like peptide hormone that inhibits duodenal iron absorption and macrophage iron release. Hamp is part of the type II acute phase response and is thought to have a crucial regulatory role in sequestering iron in the context of ACD. Mice with deficiencies in the hemochromatosis gene product, Hfe, mounted a general inflammatory response after injection of lipopolysaccharide but lacked appropriate Hamp expression and did not develop hyposideremia. These data suggest a previously unidentified role for Hfe in innate immunity and ACD.
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Affiliation(s)
- Cindy N Roy
- Children's Hospital, and Harvard Medical School, Boston, Massachusetts 02115, USA
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27
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Davies PS, Zhang AS, Anderson EL, Roy CN, Lampson MA, McGraw TE, Enns CA. Evidence for the interaction of the hereditary haemochromatosis protein, HFE, with the transferrin receptor in endocytic compartments. Biochem J 2003; 373:145-53. [PMID: 12667138 PMCID: PMC1223471 DOI: 10.1042/bj20030202] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2003] [Revised: 03/21/2003] [Accepted: 04/01/2003] [Indexed: 11/17/2022]
Abstract
HFE, the protein mutated in hereditary haemochromatosis type 1, is known to interact with the transferrin receptor (TfR) on the cell surface and during endocytosis [Gross, Irrinki, Feder and Enns (1998) J. Biol. Chem. 273, 22068-22074; Roy, Penny, Feder and Enns (1999) J. Biol. Chem. 274, 9022-9028]. However, whether they are capable of interacting with each other once inside the cell is not known. In the present study we present several lines of evidence that they do interact in endosome compartments. Cells expressing a chimaera of HFE protein with the cytoplasmic domain of lysosomal-associated membrane protein 1 (LAMP1) in place of its own (HFE-LAMP) show a decrease in the half-life of the TfR. This implies that the interaction between HFE and TfR in endosomes targets the TfR to lysosomal compartments. The interaction between TfR and HFE-LAMP was confirmed by immunoprecipitation, in addition to immunofluorescence studies. Addition of transferrin (Tf) to HFE-LAMP-expressing cells competes with HFE for binding to the TfR, thereby increasing the half-life of TfR and confirming that the HFE-LAMP-TfR complex reaches the cell surface prior to entering the endosomal vesicles and trafficking to the lysosome. These results raise the possibility that interaction of HFE and TfR in intracellular vesicles may play an important role in determining the function of HFE in iron homoeostasis, which is still unknown. Analysis of endosomal pH and the iron content of internalized Tf indicated that HFE does not appear to alter the unloading of iron from Tf in the endosome.
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Affiliation(s)
- Paige S Davies
- Department of Cell and Developmental Biology, L215, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd, Portland, OR 97239-3098, USA
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Muckenthaler M, Roy CN, Custodio AO, Miñana B, deGraaf J, Montross LK, Andrews NC, Hentze MW. Regulatory defects in liver and intestine implicate abnormal hepcidin and Cybrd1 expression in mouse hemochromatosis. Nat Genet 2003; 34:102-7. [PMID: 12704390 DOI: 10.1038/ng1152] [Citation(s) in RCA: 230] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2003] [Accepted: 04/04/2003] [Indexed: 02/07/2023]
Abstract
Individuals with hereditary hemochromatosis suffer from systemic iron overload due to duodenal hyperabsorption. Most cases arise from a founder mutation in HFE (845G-->A; ref. 2) that results in the amino-acid substitution C282Y and prevents the association of HFE with beta2-microglobulin. Mice homozygous with respect to a null allele of Hfe (Hfe-/-) or homozygous with respect to the orthologous 882G-->A mutation (Hfe(845A/845A)) develop iron overload that recapitulates hereditary hemochromatosis in humans, confirming that hereditary hemochromatosis arises from loss of HFE function. Much work has focused on an exclusive role for the intestine in hereditary hemochromatosis. HFE deficiency in intestinal crypt cells is thought to cause intestinal iron deficiency and greater expression of iron transporters such as SLC11A2 (also called DMT1, DCT1 and NRAMP2) and SLC11A3 (also called IREG1, ferroportin and MTP1; ref. 3). Published data on the expression of these transporters in the duodenum of HFE-deficient mice and humans are contradictory. In this report, we used a custom microarray to assay changes in duodenal and hepatic gene expression in Hfe-deficient mice. We found unexpected alterations in the expression of Slc39a1 (mouse ortholog of SLC11A3) and Cybrd1, which encode key iron transport proteins, and Hamp (hepcidin antimicrobial peptide), a hepatic regulator of iron transport. We propose that inappropriate regulatory cues from the liver underlie greater duodenal iron absorption, possibly involving the ferric reductase Cybrd1.
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Affiliation(s)
- Martina Muckenthaler
- European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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Abstract
The anemia of chronic disease is a common disorder that afflicts patients with a wide variety of inflammatory conditions including arthritis, malignancies, infections, and inflammatory bowel disease. It results in significant morbidity and may be severe enough to require blood transfusions. The pathogenesis of anemia of chronic disease is not fully understood, but poor maintenance of red blood cell mass has been observed at three levels: 1) iron is not efficiently recycled from reticuloendothelial macrophages to erythroid precursors, 2) erythroid precursors respond poorly to erythropoietin, and 3) red blood cell survival is decreased. Whether each of these changes is related to the same effector of the inflammatory process is unknown. We have had the opportunity to investigate severe anemia of chronic disease in an unusual group of patients with glycogen storage disease type 1a. We found that anemia was directly related to the presence of large hepatic adenomas that inappropriately produced a new peptide hormone, hepcidin. Hepcidin has recently been identified as part of the innate immune response and is a key regulator of cellular iron egress. Based on our findings in this patient group, we propose a central role for hepcidin in anemia of chronic disease, linking the inflammatory process with iron recycling and erythropoiesis. We present a hypothesis based on our findings.
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Weinstein DA, Roy CN, Fleming MD, Loda MF, Wolfsdorf JI, Andrews NC. Inappropriate expression of hepcidin is associated with iron refractory anemia: implications for the anemia of chronic disease. Blood 2002; 100:3776-81. [PMID: 12393428 DOI: 10.1182/blood-2002-04-1260] [Citation(s) in RCA: 460] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The anemia of chronic disease is a prevalent, poorly understood condition that afflicts patients with a wide variety of diseases, including infections, malignancies, and rheumatologic disorders. It is characterized by a blunted erythropoietin response by erythroid precursors, decreased red blood cell survival, and a defect in iron absorption and macrophage iron retention, which interrupts iron delivery to erythroid precursor cells. We noted that patients with large hepatic adenomas had severe iron refractory anemia similar to that observed in anemia of chronic disease. This anemia resolved spontaneously after adenoma resection or liver transplantation. We investigated the role of the adenomas in the pathogenesis of the anemia and found that they produce inappropriately high levels of hepcidin mRNA. Hepcidin is a peptide hormone that has been implicated in controlling the release of iron from cells. We conclude that hepcidin plays a major, causative role in the anemia observed in our subgroup of patients with hepatic adenomas, and we speculate that it is important in the pathogenesis of the anemia of chronic disease in general.
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31
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Roy CN, Blemings KP, Deck KM, Davies PS, Anderson EL, Eisenstein RS, Enns CA. Increased IRP1 and IRP2 RNA binding activity accompanies a reduction of the labile iron pool in HFE-expressing cells. J Cell Physiol 2002; 190:218-26. [PMID: 11807826 DOI: 10.1002/jcp.10056] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Iron regulatory proteins (IRPs), the cytosolic proteins involved in the maintenance of cellular iron homeostasis, bind to stem loop structures found in the mRNA of key proteins involved iron uptake, storage, and metabolism and regulate the expression of these proteins in response to changes in cellular iron needs. We have shown previously that HFE-expressing fWTHFE/tTA HeLa cells have slightly increased transferrin receptor levels and dramatically reduced ferritin levels when compared to the same clonal cell line without HFE (Gross et al., 1998, J Biol Chem 273:22068-22074). While HFE does not alter transferrin receptor trafficking or non-transferrin mediated iron uptake, it does specifically reduce (55)Fe uptake from transferrin (Roy et al., 1999, J Biol Chem 274:9022-9028). In this report, we show that IRP RNA binding activity is increased by up to 5-fold in HFE-expressing cells through the activation of both IRP isoforms. Calcein measurements show a 45% decrease in the intracellular labile iron pool in HFE-expressing cells, which is in keeping with the IRP activation. These results all point to the direct effect of the interaction of HFE with transferrin receptor in lowering the intracellular labile iron pool and establishing a new set point for iron regulation within the cell.
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Affiliation(s)
- Cindy N Roy
- Department of Cell and Developmental Biology, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA
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Abstract
The spectrum of known disorders of iron metabolism has expanded dramatically over the past few years. Identification of HFE, the gene most commonly mutated in patients with hereditary hemochromatosis, has allowed molecular diagnosis and paved the way for identification of other genes, such as TFR2, that are important in non-HFE-associated iron overload. There are clearly several other, unidentified, iron overload disease genes yet to be found. In parallel, our understanding of iron transport has expanded through identification of Fpn1/Ireg1/MTP1, Sfxn1 and DCYTB: Ongoing studies of Friedreich's ataxia, sideroblastic anemia, aceruloplasminemia and neurodegeneration with brain-iron accumulation are clarifying the role for iron in the nervous system. Finally, as the number of known iron metabolic genes increases and their respective functions are ascertained, new opportunities have arisen to identify genetic modifiers of iron homeostasis.
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Affiliation(s)
- C N Roy
- Division of Hematology/Oncology, Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
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Roy CN, Enns CA. Iron homeostasis: new tales from the crypt. Blood 2000; 96:4020-7. [PMID: 11110669] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023] Open
Abstract
The enterocyte is a highly specialized cell of the duodenal epithelium that coordinates iron uptake and transport into the body. Until recently, the molecular mechanisms underlying iron absorption and iron homeostasis have remained a mystery. This review focuses on the proteins and regulatory mechanisms known to be present in the enterocyte precursor cell and in the mature enterocyte. The recent cloning of a basolateral iron transporter and investigations into its regulation provide new insights into possible mechanisms for iron transport and homeostasis. The roles of proteins such as iron regulatory proteins, the hereditary hemochromatosis protein (HFE)-transferrin receptor complex, and hephaestin in regulating this transporter and in regulating iron transport across the intestinal epithelium are discussed. A speculative, but testable, model for the maintenance of iron homeostasis, which incorporates the changes in the iron-related proteins associated with the life cycle of the enterocyte as it journeys from the crypt to the tip of the villous is proposed.
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Affiliation(s)
- C N Roy
- Department of Cell and Developmental Biology, Oregon Health Sciences University, Portland, OR 97201-3098, USA
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Roy CN, Carlson EJ, Anderson EL, Basava A, Starnes SM, Feder JN, Enns CA. Interactions of the ectodomain of HFE with the transferrin receptor are critical for iron homeostasis in cells. FEBS Lett 2000; 484:271-4. [PMID: 11078891 DOI: 10.1016/s0014-5793(00)02173-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Expression of wild type HFE reduces the ferritin levels of cells in culture. In this report we demonstrate that the predominant hereditary hemochromatosis mutation, C282Y(2) HFE, does not reduce ferritin expression. However, the second mutation, H63D HFE, reduces ferritin expression to a level indistinguishable from cells expressing wild type HFE. Further, two HFE cytoplasmic domain mutations engineered to disrupt potential signal transduction, S335M and Y342C, were functionally indistinguishable from wild type HFE in this assay, as was soluble HFE. These results implicate a role for the interaction of HFE with the transferrin receptor in lowering cellular ferritin levels.
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Affiliation(s)
- C N Roy
- Department of Cell and Developmental Biology, Oregon Health Sciences University, Portland 97201-3098, USA
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Roy CN, Penny DM, Feder JN, Enns CA. The hereditary hemochromatosis protein, HFE, specifically regulates transferrin-mediated iron uptake in HeLa cells. J Biol Chem 1999; 274:9022-8. [PMID: 10085150 DOI: 10.1074/jbc.274.13.9022] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
HFE is the protein product of the gene mutated in the autosomal recessive disease hereditary hemochromatosis (Feder, J. N., Gnirke, A., Thomas, W., Tsuchihashi, Z., Ruddy, D. A., Basava, A., Dormishian, F., Domingo, R. J., Ellis, M. C., Fullan, A., Hinton, L. M., Jones, N. L., Kimmel, B. E., Kronmal, G. S., Lauer, P., Lee, V. K., Loeb, D. B., Mapa, F. A., McClelland, E., Meyer, N. C., Mintier, G. A., Moeller, N., Moore, T., Morikang, E., Prasss, C. E., Quintana, L., Starnes, S. M., Schatzman, R. C., Brunke, K. J., Drayna, D. T., Risch, N. J., Bacon, B. R., and Wolff, R. R. (1996) Nat. Genet. 13, 399-408). At the cell surface, HFE complexes with transferrin receptor (TfR), increasing the dissociation constant of transferrin (Tf) for its receptor 10-fold (Gross, C. N., Irrinki, A., Feder, J. N., and Enns, C. A. (1998) J. Biol. Chem. 273, 22068-22074; Feder, J. N., Penny, D. M., Irrinki, A., Lee, V. K., Lebron, J. A., Watson, N. , Tsuchihashi, Z., Sigal, E., Bjorkman, P. J., and Schatzman, R. C. (1998) Proc. Natl. Acad. Sci. U S A 95, 1472-1477). HFE does not remain at the cell surface, but traffics with TfR to Tf-positive internal compartments (Gross et al., 1998). Using a HeLa cell line in which the expression of HFE is controlled by tetracycline, we show that the expression of HFE reduces 55Fe uptake from Tf by 33% but does not affect the endocytic or exocytic rates of TfR cycling. Therefore, HFE appears to reduce cellular acquisition of iron from Tf within endocytic compartments. HFE specifically reduces iron uptake from Tf, as non-Tf-mediated iron uptake from Fe-nitrilotriacetic acid is not altered. These results explain the decreased ferritin levels seen in our HeLa cell system and demonstrate the specific control of HFE over the Tf-mediated pathway of iron uptake. These results also have implications for the understanding of cellular iron homeostasis in organs such as the liver, pancreas, heart, and spleen that are iron loaded in hereditary hemochromatotic individuals lacking functional HFE.
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Affiliation(s)
- C N Roy
- Department of Cell and Developmental Biology, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA
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