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Thomas TA, Qiu A, Kim CY, Gordy DE, Miller A, Tredicine M, Dzieciatkowska M, Dei Zotti F, Hod EA, D'Alessandro A, Zimring JC, Spitalnik SL, Hudson KE. Reticulocytes in donor blood units enhance red blood cell alloimmunization. Haematologica 2023; 108:2639-2651. [PMID: 37078267 PMCID: PMC10543191 DOI: 10.3324/haematol.2023.282815] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/12/2023] [Indexed: 04/21/2023] Open
Abstract
Although red blood cell (RBC) transfusions save lives, some patients develop clinically-significant alloantibodies against donor blood group antigens, which then have adverse effects in multiple clinical settings. Few effective measures exist to prevent RBC alloimmunization and/or eliminate alloantibodies in sensitized patients. Donor-related factors may influence alloimmunization; thus, there is an unmet clinical need to identify which RBC units are immunogenic. Repeat volunteer blood donors and donors on iron supplements have elevated reticulocyte counts compared to healthy non-donors. Early reticulocytes retain mitochondria and other components, which may act as danger signals in immune responses. Herein, we tested whether reticulocytes in donor RBC units could enhance RBC alloimmunization. Using a murine model, we demonstrate that transfusing donor RBC units with increased reticulocyte frequencies dose-dependently increased RBC alloimmunization rates and alloantibody levels. Transfusing reticulocyte-rich RBC units was associated with increased RBC clearance from the circulation and a robust proinflammatory cytokine response. As compared to previously reported post-transfusion RBC consumption patterns, erythrophagocytosis from reticulocyte-rich units was increasingly performed by splenic B cells. These data suggest that reticulocytes in a donated RBC unit impact the quality of blood transfused, are targeted to a distinct compartment, and may be an underappreciated risk factor for RBC alloimmunization.
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Affiliation(s)
- Tiffany A Thomas
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Annie Qiu
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Christopher Y Kim
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Dominique E Gordy
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Anabel Miller
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Maria Tredicine
- Department of Translational Medicine and Surgery, Section of General Pathology, Università Cattolica del Sacro Cuore, Rome
| | - Monika Dzieciatkowska
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver - Anschutz Medical Campus, Aurora, CO
| | - Flavia Dei Zotti
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Eldad A Hod
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Angelo D'Alessandro
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver - Anschutz Medical Campus, Aurora, CO
| | - James C Zimring
- University of Virginia School of Medicine, Charlottesville, VA, USA; Carter Immunology Center, University of Virginia, Charlottesville, VA
| | - Steven L Spitalnik
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY
| | - Krystalyn E Hudson
- Laboratory of Transfusion Biology, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY.
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Thomas TA, Qiu A, Kim CY, Gordy DE, Miller A, Tredicine M, Dzieciatkowska M, Zotti FD, Hod EA, Dâ Alessandro A, Zimring JC, Spitalnik SL, Hudson KE. Reticulocytes in donor RBC units enhance RBC alloimmunization. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.25.525560. [PMID: 36747702 PMCID: PMC9900826 DOI: 10.1101/2023.01.25.525560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Although red blood cell (RBC) transfusions save lives, some patients develop clinically-significant alloantibodies against donor blood group antigens, which then have adverse effects in multiple clinical settings. Few effective measures exist to prevent RBC alloimmunization and/or eliminate alloantibodies in sensitized patients. Donor-related factors may influence alloimmunization; thus, there is an unmet clinical need to identify which RBC units are immunogenic. Repeat volunteer blood donors and donors on iron supplements have elevated reticulocyte counts compared to healthy non-donors. Early reticulocytes retain mitochondria and other components, which may act as danger signals in immune responses. Herein, we tested whether reticulocytes in donor RBC units could enhance RBC alloimmunization. Using a murine model, we demonstrate that transfusing donor RBC units with increased reticulocyte frequencies dose-dependently increase RBC alloimmunization rates and alloantibody levels. Transfusing reticulocyte-rich RBC units was associated with increased RBC clearance from the circulation and a robust proinflammatory cytokine response. As compared to previously reported post-transfusion RBC consumption patterns, erythrophagocytosis from reticulocyte-rich units was increasingly performed by splenic B cells. These data suggest that reticulocytes in a donated RBC unit impact the quality of blood transfused, are targeted to a distinct compartment, and may be an underappreciated risk factor for RBC alloimmunization.
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Manabe E, Ito S, Ohno Y, Tanaka T, Naito Y, Sasaki N, Asakura M, Masuyama T, Ishihara M, Tsujino T. Reduced lifespan of erythrocytes in Dahl/Salt sensitive rats is the cause of the renal proximal tubule damage. Sci Rep 2020; 10:22023. [PMID: 33328561 PMCID: PMC7744793 DOI: 10.1038/s41598-020-79146-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 12/01/2020] [Indexed: 12/20/2022] Open
Abstract
We studied the mechanisms of anemia and the influence of anemia on renal pathology in Dahl/Salt Sensitive (Dahl/SS) rat, a model of cardio-renal-anemia syndrome. Erythrocyte lifespan was shortened and associated with decreased hemoglobin level in the Dahl/SS rats given high-salt diet. Serum haptoglobin decreased, reticulocytes increased, and erythropoiesis in the bone marrow and extramedullary hematopoiesis in the spleen was markedly stimulated by increased serum erythropoietin in them. As a mechanism of hemolysis, we investigated the incidence of eryptosis, suicidal death of erythrocytes. Eryptosis was increased, and red blood cell-derived microparticles, small particle which are generated in hemolytic disease, were also increased in Dahl/SS rats fed with high-salt diet. Deposition of hemosiderin and mitochondrial morphologic abnormality, a sign of ferroptosis, in proximal renal tubules was associated with intravascular hemolysis. Treatment with deferasirox, an oral iron chelator, reduced the renal proximal tubular injury and the glomerular sclerosis in Dahl/SS rats fed with high-salt diet. In conclusion, reduced half-life of erythrocytes induced by hemolysis is the major cause of anemia in Dahl/SS rat. Iron accumulation induced by hemolysis causes renal proximal tubule injury and accelerates renal damage in this model.
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Affiliation(s)
- Eri Manabe
- Department of Cardiovascular and Renal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan.
| | - Satoyasu Ito
- Division of Pharmaceutical Therapeutics, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe, Hyogo, Japan
| | - Yoshiya Ohno
- Division of Immunobiology, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe, Hyogo, Japan
| | - Toshiyuki Tanaka
- Division of Immunobiology, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe, Hyogo, Japan
| | - Yoshiro Naito
- Department of Cardiovascular and Renal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
| | - Naoko Sasaki
- Division of Pharmaceutical Therapeutics, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe, Hyogo, Japan
| | - Masanori Asakura
- Department of Cardiovascular and Renal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
| | - Tohru Masuyama
- Department of Cardiovascular and Renal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
- Hoshigaoka Medical Center, Japan Community Health Care Organization, Hirakata, Osaka, Japan
| | - Masaharu Ishihara
- Department of Cardiovascular and Renal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
| | - Takeshi Tsujino
- Department of Cardiovascular and Renal Medicine, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, 663-8501, Japan
- Division of Pharmaceutical Therapeutics, Department of Pharmacy, School of Pharmacy, Hyogo University of Health Sciences, Kobe, Hyogo, Japan
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D'onofrio G, Zini G, Brugnara C. Clinical Applications of Automated Reticulocyte Indices. Hematology 2016; 3:165-76. [DOI: 10.1080/10245332.1998.11746388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Affiliation(s)
- Giuseppe D'onofrio
- Research Center for the Development and Clinical Evaluation of Automated Methods in Hematology, Department of Hematology, Università Cattolica del Sacro Cuore, Rome, Italy; Departments of Laboratory Medicine and Pathology, Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Gina Zini
- Research Center for the Development and Clinical Evaluation of Automated Methods in Hematology, Department of Hematology, Università Cattolica del Sacro Cuore, Rome, Italy; Departments of Laboratory Medicine and Pathology, Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Carlo Brugnara
- Research Center for the Development and Clinical Evaluation of Automated Methods in Hematology, Department of Hematology, Università Cattolica del Sacro Cuore, Rome, Italy; Departments of Laboratory Medicine and Pathology, Children's Hospital and Harvard Medical School, Boston, MA, USA
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Wiczling P, Krzyzanski W, Zychlińska N, Lewandowski K, Kaliszan R. The quantification of reticulocyte maturation and neocytolysis in normal and erythropoietin stimulated rats. Biopharm Drug Dispos 2014; 35:330-40. [PMID: 24888906 DOI: 10.1002/bdd.1902] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 02/19/2014] [Accepted: 05/20/2014] [Indexed: 11/11/2022]
Abstract
A technique has recently been proposed for obtaining the reticulocyte (RET) age distribution from the flow cytometric reticulocyte count. It allows for a quantitative characterization of reticulocyte dynamics. In this work this technique was applied to characterize the blood, bone marrow and spleen reticulocytes in homeostatic and erythropoietically stimulated rats in order to determine the reticulocyte maturation times in the bone marrow and blood; and to confirm the presence of ineffective erythropoiesis (neocytolysis). The latter was done by comparing the reticulocyte removal rate from blood with bilirubin formation after erythropoiesis stimulation. A single subcutaneous dose (4050 IU/kg) of recombinant human erythropoietin (rHuEPO) was administered to rats, then their reticulocytes were stained with thiazole orange and the distribution of the fluorescent signal measured using flow cytometry. The obtained signal distribution of the reticulocytes was transformed to the age distribution and a set of basic parameters reflecting reticulocyte dynamics was determined. Bilirubin concentrations were measured to directly assess the presence of reticulocyte irreversible removal. The bilirubin formation was found to be considerably modulated by rHuEPO and corresponded well to the determined reticulocyte removal rate. The initial increase and subsequent decrease of the reticulocyte maturation time in blood was quantitated and directly linked with RET mobilization from the bone marrow. A substantial number (60%) of reticulocytes is sequestrated during homeostasis in rats. This number increases and then decreases after rHuEPO administration, as also reflected by bilirubin formation. Flow cytometry seems to be an excellent method for studying RET dynamics and the presence of young RBC neocytolysis.
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Affiliation(s)
- Paweł Wiczling
- Department of Biopharmaceutics and Pharmacodynamics, Medical University of Gdańsk, Gdańsk, Poland
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Andrews DA, Boren BM, Turk JR, Boyce RW, He YD, Hamadeh HK, Mytych DT, Barger TE, Salimi-Moosavi H, Sloey B, Elliott S, McElroy P, Sinclair AM, Shimamoto G, Pyrah ITG, Lightfoot-Dunn RM. Dose-related Differences in the Pharmacodynamic and Toxicologic Response to a Novel Hyperglycosylated Analog of Recombinant Human Erythropoietin in Sprague-Dawley Rats with Similarly High Hematocrit. Toxicol Pathol 2013; 42:524-39. [DOI: 10.1177/0192623313486319] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
We recently reported results that erythropoiesis-stimulating agent (ESA)–related thrombotic toxicities in preclinical species were not solely dependent on a high hematocrit (HCT) but also associated with increased ESA dose level, dose frequency, and dosing duration. In this article, we conclude that sequelae of an increased magnitude of ESA-stimulated erythropoiesis potentially contributed to thrombosis in the highest ESA dose groups. The results were obtained from two investigative studies we conducted in Sprague-Dawley rats administered a low (no thrombotic toxicities) or high (with thrombotic toxicities) dose level of a hyperglycosylated analog of recombinant human erythropoietin (AMG 114), 3 times weekly for up to 9 days or for 1 month. Despite similarly increased HCT at both dose levels, animals in the high-dose group had an increased magnitude of erythropoiesis measured by spleen weights, splenic erythropoiesis, and circulating reticulocytes. Resulting prothrombotic risk factors identified predominantly or uniquely in the high-dose group were higher numbers of immature reticulocytes and nucleated red blood cells in circulation, severe functional iron deficiency, and increased intravascular destruction of iron-deficient reticulocyte/red blood cells. No thrombotic events were detected in rats dosed up to 9 days suggesting a sustained high HCT is a requisite cofactor for development of ESA-related thrombotic toxicities.
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Affiliation(s)
- Dina A. Andrews
- Comparative Biology Safety Sciences, Pathology, Amgen Inc., Thousand Oaks, California, USA
| | - Babette M. Boren
- Comparative Biology Safety Sciences, Toxicology Sciences, Amgen Inc., Thousand Oaks, California, USA
| | - James R. Turk
- Comparative Biology Safety Sciences, Pathology, Amgen Inc., Thousand Oaks, California, USA
| | - Rogely W. Boyce
- Comparative Biology Safety Sciences, Pathology, Amgen Inc., Thousand Oaks, California, USA
| | - Yudong D. He
- Comparative Biology and Safety Sciences, Discovery Toxicology, Amgen Inc., Seattle, Washington, USA
| | - Hisham K. Hamadeh
- Comparative Biology and Safety Sciences, Discovery Toxicology, Amgen Inc., Thousand Oaks, California, USA
| | - Daniel T. Mytych
- Medical Sciences, Clinical Immunology, Amgen Inc., Thousand Oaks, California, USA
| | - Troy E. Barger
- Medical Sciences, Clinical Immunology, Amgen Inc., Thousand Oaks, California, USA
| | | | - Bethlyn Sloey
- Pharmacokinetics and Drug Metabolism, Amgen Inc., Thousand Oaks, California, USA
| | - Steve Elliott
- Discovery Research, Oncology Research, Amgen Inc., Thousand Oaks, California, USA
| | - Patricia McElroy
- Discovery Research, Oncology Research, Amgen Inc., Thousand Oaks, California, USA
| | - Angus M. Sinclair
- Discovery Research, Oncology Research, Amgen Inc., Thousand Oaks, California, USA
| | - Grant Shimamoto
- Therapeutic Discovery, Biologic Optimization, Amgen Inc., Thousand Oaks, California, USA
| | - Ian T. G. Pyrah
- Comparative Biology Safety Sciences, Executive and Operations, Amgen, Inc., Thousand Oaks, California, USA
| | - Ruth M. Lightfoot-Dunn
- Comparative Biology Safety Sciences, Executive and Operations, Amgen, Inc., Thousand Oaks, California, USA
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Wiczling P, Ait-Oudhia S, Krzyzanski W. Flow cytometric analysis of reticulocyte maturation after erythropoietin administration in rats. Cytometry A 2009; 75:584-92. [PMID: 19437531 DOI: 10.1002/cyto.a.20736] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We have proposed a technique for transforming reticulocyte (RET) flow cytometry count into the age distribution allowing for a quantitative characterization of RETs dynamics. This technique was evaluated in homeostatic and erythropoietically stimulated rats. We administered a single intravenous dose (4,050 IU/kg) of recombinant human erythropoietin to Wistar rats, then stained their RETs with thiazole orange, and measured the distribution of the fluorescent signal using flow cytometry. The RET age distribution was determined assuming an exponential decline of RET RNA. The RET distribution over time was characterized by median age, production rate of mature red blood cell in the blood, bone marrow and blood maturation times, and RET loss from the blood. Erythropoietin was found to cause complex changes not only in RET count but also in age distribution. Generally, an increase in RET count was accompanied by the presence of young RETs and a decrease with the presence of old RETs. The rate at which RETs were removed from the blood was affected considerably by erythropoietin administration, and their death was attributed to it. Flow cytometric analysis of RET age distribution expands our understanding of erythropoiesis and augments the information we can obtain from RET measurements.
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Affiliation(s)
- Pawel Wiczling
- Department of Pharmaceutical Sciences, University at Buffalo, New York 14260, USA
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Landaw SA, Russell ES, Bernstein SE. Splenic destruction of newly-formed red blood cells and shortened erythrocyte survival in mice with congenital microcytosis. SCANDINAVIAN JOURNAL OF HAEMATOLOGY 2009; 7:516-24. [PMID: 5507573 DOI: 10.1111/j.1600-0609.1970.tb01940.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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9
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Brugnara C. Reticulocyte cellular indices: a new approach in the diagnosis of anemias and monitoring of erythropoietic function. Crit Rev Clin Lab Sci 2000; 37:93-130. [PMID: 10811141 DOI: 10.1080/10408360091174196] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Reticulocyte analysis has been extended from the simple enumeration of reticulocytes to precise measurements of mRNA content and of cellular indices such as volume, hemoglobin (Hb) concentration, and content. Assessment of reticulocyte maturity is based on the fluorescence intensity of reticulocytes, which depends on RNA content. The appearance of high fluorescence reticulocytes has been shown to be associated with engraftment in the setting of bone marrow or peripheral stem cells transplantation, although it is still not clear how this parameter can improve quality or cost of care compared with the traditional use of absolute neutrophil counts. Reticulocyte indices have been studied especially in the setting of iron deficiency and functional iron deficiency during recombinant human erythropoietin (r-HuEPO) therapy. Reticulocyte hemoglobin content (CHr) may allow prompt identification of an imbalance between r-HuEPO therapy and iron availability by detecting the presence in reticulocytes of iron-restricted erythropoiesis. Diagnosis of simple iron deficiency can also be achieved in a more cost-effective fashion by using CHr in conjunction with the regular complete blood count (CBC), rather than relying on the traditional biochemical parameters of iron metabolism. Response to therapy of megaloblastic anemia can also be monitored with CHr. These new reticulocyte parameters provide a real-time assessment of the functional state of erythropoiesis.
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Affiliation(s)
- C Brugnara
- Department of Laboratory Medicine, Children's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Brugnara C. Use of reticulocyte cellular indices in the diagnosis and treatment of hematological disorders. INTERNATIONAL JOURNAL OF CLINICAL & LABORATORY RESEARCH 1998; 28:1-11. [PMID: 9594357 DOI: 10.1007/s005990050011] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Automated counting of reticulocytes has markedly increased the precision and accuracy of this assay compared with the traditional manual counts. In addition, several new reticulocyte parameters are now available to clinicians and pathologists. This review examines the potential role of these parameters in the diagnosis and management of anemias. Reticulocyte maturity can now be assessed based on the staining intensity of reticulocytes, which is proportional to their RNA content. However, the clinical value of the numerical estimate of the immature reticulocyte fraction has not been yet demonstrated. In the bone marrow transplant setting, there is no clear evidence that the use of this index results in improved care of these patients, and many studies have failed to show its superiority compared with the traditional white cell count, especially for autologous transplants. Direct measurement of reticulocyte volume, hemoglobin concentration, and hemoglobin content are now available. Studies have shown that these parameters, and hemoglobin content in particular, allow a real-time assessment of the functional state of the erythroid marrow. In the setting of recombinant human erythropoietin therapy, studies of hemoglobin content have shown that this index allows an early detection of functional iron deficiency. Preliminary studies have also shown that this index may be helpful in the diagnosis of iron deficiency and in the monitoring of iron replacement therapy.
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Affiliation(s)
- C Brugnara
- Department of Pathology, Harvard Medical School, Boston, Massachusetts, USA
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12
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Gemsa D, Schmid R. [Hemoglobin metabolism and bilirubin formation]. KLINISCHE WOCHENSCHRIFT 1974; 52:609-16. [PMID: 4603574 DOI: 10.1007/bf01468795] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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14
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Come SE, Shohet SB, Robinson SH. Surface remodelling of reticulocytes produced in response to erythroid stress. NATURE: NEW BIOLOGY 1972; 236:157-8. [PMID: 4502824 DOI: 10.1038/newbio236157a0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Robinson SH, Koeppel E. Preferential hemolysis of immature erythrocytes in experimental iron deficiency anemia: source of erythropoietic bilirubin formation. J Clin Invest 1971; 50:1847-53. [PMID: 5564391 PMCID: PMC292110 DOI: 10.1172/jci106676] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Bilirubin-(14)C production was measured in rats transfused with labeled erythrocytes from animals with iron deficiency anemia, a condition associated with ineffective erythropoiesis. With labeled reticulocytes harvested 1 day after the administration of glycine-2-(14)C, conversion of hemoglobin-(14)C to bilirubin averaged 47.3% over the 3 days of observation; the corresponding value for reticulocytes from normal rats was only 1.7%. Findings were not altered by splenectomy. Bilirubin-(14)C production fell to 35.8% with iron-deficient cells harvested 3 days after glycine-(14)C administration, and declined further to a plateau averaging 25% with cells labeled 5, 7, 10, or 15 days earlier. The latter values still far exceed those for mature erythrocytes from normal animals.The findings indicate that experimental iron deficiency anemia is associated with hemolysis of red cells of various ages, but with preferential destruction of the youngest cells. Degradation of hemoglobin from reticulocytes is sufficient to account for a major fraction of the increase in erythropoietic bilirubin production found in this disorder, as has also been shown for physiologically regulated erythroid hyperplasia. However, the defect is quantitatively much more striking in experimental iron deficiency, and this and perhaps a similar defect in bone marrow cells appear to explain the decrease in net hemoglobin production that is characteristic of pathologic ineffective erythropoiesis.
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Abstract
Previous studies of red cell structure and metabolism during the aging process have relied upon in vitro techniques of cell separation into various age populations. Probably the most common approach is to isolate the older red cells with the assumption that they are more dense. This may lead to a number of inconsistencies in observations, and may certainly raise questions about possible cell changes secondary to manipulative procedures. For this reason, an experimental system was devised where a normal red cell population could be studied, while aging, in an in vivo environment. The initial red cell mass of a large number of inbred rats was transferred repeatedly into an ever smaller number of animals, making it possible to follow an aging population of red cells up to 48 days while preventing contamination with newly produced cells by suppression of erythropoiesis with transfusion-induced polycythemia. During this period, samples of progressively older red cells could be obtained for measurements of red cell constant. It was noted that the normal rat red cell undergoes both volume reduction and significant hemoglobin content loss with aging. In addition, the hemoglobin concentration within the cell demonstrated an early rise after a return to nearly normal values. These findings are noteworthy in that they help to explain the characteristics of life-spans of cohort labeled red cell populations in small animals, and provide a possible example of a cell's remodeling process within the spleen.
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