1
|
Lee J, Rogers HM, Springer DA, Noguchi CT. Neuronal nitric oxide synthase required for erythropoietin modulation of heart function in mice. Front Physiol 2024; 15:1338476. [PMID: 38628440 PMCID: PMC11019009 DOI: 10.3389/fphys.2024.1338476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Accepted: 03/04/2024] [Indexed: 04/19/2024] Open
Abstract
Introduction: Erythropoietin (EPO) acts primarily in regulating red blood cell production mediated by high EPO receptor (EPOR) expression in erythroid progenitor cells. EPO activity in non-erythroid tissue is evident in mice with EPOR restricted to erythroid tissues (ΔEPORE) that become obese, glucose-intolerant, and insulin-resistant. In animal models, nitric oxide synthase (NOS) contributes to EPO activities including erythropoiesis, neuroprotection, and cardioprotection against ischemia-reperfusion injury. However, we found that extended EPO treatment to increase hematocrit compromised heart function, while the loss of neuronal NOS (nNOS) was protective against the deleterious activity of EPO to promote heart failure. Methods: Wild-type (WT) mice, ΔEPORE mice, and nNOS-knockout mice (nNOS-/-) were placed on a high-fat diet to match the ΔEPORE obese phenotype and were treated with EPO for 3 weeks. Hematocrit and metabolic response to EPO treatment were monitored. Cardiac function was assessed by echocardiography and ultrasonography. Results: ΔEPORE mice showed a decrease in the left ventricular outflow tract (LVOT) peak velocity, ejection fraction, and fractional shortening, showing that endogenous non-erythroid EPO response is protective for heart function. EPO treatment increased hematocrit in all mice and decreased fat mass in male WT, demonstrating that EPO regulation of fat mass requires non-erythroid EPOR. EPO treatment also compromised heart function in WT mice, and decreased the pulmonary artery peak velocity (PA peak velocity), LVOT peak velocity, ejection fraction, and fractional shortening, but it had minimal effect in further reducing the heart function in ΔEPORE mice, indicating that the adverse effect of EPO on heart function is not related to EPO-stimulated erythropoiesis. ΔEPORE mice had increased expression of heart failure-associated genes, hypertrophic cardiomyopathy-related genes, and sarcomeric genes that were also elevated with EPO treatment in WT mice. Male and female nNOS-/- mice were protected against diet-induced obesity. EPO treatment in nNOS-/- mice increased the hematocrit that tended to be lower than WT mice and decreased the PA peak velocity but did not affect the LVOT peak velocity, ejection fraction, and fractional shortening, suggesting that nNOS is required for the adverse effect of EPO treatment on heart function in WT mice. EPO treatment did not change expression of heart failure-associated gene expression in nNOS-/- mice. Discussion: Endogenous EPO has a protective effect on heart function. With EPO administration, in contrast to the protective effect to the cardiac injury of acute EPO treatment, extended EPO treatment to increase hematocrit in WT mice adversely affected the heart function with a corresponding increase in expression of heart failure-associated genes. This EPO activity was independent of EPO-stimulated erythropoiesis and required EPOR in non-erythroid tissue and nNOS activity, while nNOS-/- mice were protected from the EPO-associated adverse effect on heart function. These data provide evidence that nNOS contributes to the negative impact on the heart function of high-dose EPO treatment for anemia.
Collapse
Affiliation(s)
- Jeeyoung Lee
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Heather M. Rogers
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| | - Danielle A. Springer
- Murine Phenotyping Core, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, United States
| | - Constance T. Noguchi
- Molecular Medicine Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States
| |
Collapse
|
2
|
Brown TJ, Hammers M, Taylor M, Dugdale HL, Komdeur J, Richardson DS. Hematocrit, age, and survival in a wild vertebrate population. Ecol Evol 2021; 11:214-226. [PMID: 33437424 PMCID: PMC7790625 DOI: 10.1002/ece3.7015] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 10/23/2020] [Indexed: 12/18/2022] Open
Abstract
Understanding trade-offs in wild populations is difficult, but important if we are to understand the evolution of life histories and the impact of ecological variables upon them. Markers that reflect physiological state and predict future survival would be of considerable benefit to unraveling such trade-offs and could provide insight into individual variation in senescence. However, currently used markers often yield inconsistent results. One underutilized measure is hematocrit, the proportion of blood comprising erythrocytes, which relates to the blood's oxygen-carrying capacity and viscosity, and to individual endurance. Hematocrit has been shown to decline with age in cross-sectional studies (which may be confounded by selective appearance/disappearance). However, few studies have tested whether hematocrit declines within individuals or whether low hematocrit impacts survival in wild taxa. Using longitudinal data from the Seychelles warbler (Acrocephalus sechellensis), we demonstrated that hematocrit increases with age in young individuals (<1.5 years) but decreases with age in older individuals (1.5-13 years). In breeders, hematocrit was higher in males than females and varied relative to breeding stage. High hematocrit was associated with lower survival in young individuals, but not older individuals. Thus, while we did not find support for hematocrit as a marker of senescence, high hematocrit is indicative of poor condition in younger individuals. Possible explanations are that these individuals were experiencing dehydration and/or high endurance demands prior to capture, which warrants further investigation. Our study demonstrates that hematocrit can be an informative metric for life-history studies investigating trade-offs between survival, longevity, and reproduction.
Collapse
Affiliation(s)
- Thomas J. Brown
- School of Biological SciencesUniversity of East AngliaNorwichUK
| | - Martijn Hammers
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - Martin Taylor
- School of Biological SciencesUniversity of East AngliaNorwichUK
| | - Hannah L. Dugdale
- School of BiologyFaculty of Biological SciencesUniversity of LeedsLeedsUK
| | - Jan Komdeur
- Groningen Institute for Evolutionary Life SciencesUniversity of GroningenGroningenThe Netherlands
| | - David S. Richardson
- School of Biological SciencesUniversity of East AngliaNorwichUK
- Nature SeychellesVictoriaMahéSeychelles
| |
Collapse
|
3
|
Perron-Deshaies G, St-Louis P, Romero H, Scorza T. Impact of Erythropoietin Production by Erythroblastic Island Macrophages on Homeostatic Murine Erythropoiesis. Int J Mol Sci 2020; 21:ijms21238930. [PMID: 33255601 PMCID: PMC7728051 DOI: 10.3390/ijms21238930] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 11/20/2020] [Accepted: 11/23/2020] [Indexed: 11/16/2022] Open
Abstract
Erythropoietin (EPO) is an essential hormone for erythropoiesis, protecting differentiating erythroblasts against apoptosis. EPO has been largely studied in stress or pathological conditions but its regulatory role in steady state erythropoiesis has been less documented. Herein, we report production of EPO by bone marrow-derived macrophages (BMDM) in vitro, and its further enhancement in BMDM conditioned with media from apoptotic cells. Confocal microscopy confirmed EPO production in erythroblastic island (EBI)-associated macrophages, and analysis of mice depleted of EBI macrophages by clodronate liposomes revealed drops in EPO levels in bone marrow (BM) cell lysates, and decreased percentages of EPO-responsive erythroblasts in the BM. We hypothesize that EBI macrophages are an in-situ source of EPO and sustain basal erythropoiesis in part through its secretion. To study this hypothesis, mice were injected with clodronate liposomes and were supplied with exogenous EPO (1-10 IU/mouse) to evaluate potential rescue of the deficiency in erythroid cells. Our results show that at doses of 5 and 10 IU, EPO significantly rescues BM steady state erythropoiesis in mice deficient of macrophages. We propose existence of a mechanism by which EBI macrophages secrete EPO in response to apoptotic erythroblasts, which is in turn controlled by the numbers of erythroid precursors generated.
Collapse
Affiliation(s)
- Genève Perron-Deshaies
- Département des Sciences Biologiques, Université du Québec à Montréal, Montreal, QC H3C 3P8, Canada; (G.P.-D.); (P.S.-L.); (H.R.)
| | - Philippe St-Louis
- Département des Sciences Biologiques, Université du Québec à Montréal, Montreal, QC H3C 3P8, Canada; (G.P.-D.); (P.S.-L.); (H.R.)
| | - Hugo Romero
- Département des Sciences Biologiques, Université du Québec à Montréal, Montreal, QC H3C 3P8, Canada; (G.P.-D.); (P.S.-L.); (H.R.)
- CHU Sainte-Justine Research Centre, Montreal, QC H3T 1C5, Canada
| | - Tatiana Scorza
- Département des Sciences Biologiques, Université du Québec à Montréal, Montreal, QC H3C 3P8, Canada; (G.P.-D.); (P.S.-L.); (H.R.)
- Correspondence: ; Tel.: +1-514-9873000 (ext. 1918)
| |
Collapse
|
4
|
Rao TN, Hansen N, Hilfiker J, Rai S, Majewska JM, Leković D, Gezer D, Andina N, Galli S, Cassel T, Geier F, Delezie J, Nienhold R, Hao-Shen H, Beisel C, Di Palma S, Dimeloe S, Trebicka J, Wolf D, Gassmann M, Fan TWM, Lane AN, Handschin C, Dirnhofer S, Kröger N, Hess C, Radimerski T, Koschmieder S, Čokić VP, Skoda RC. JAK2-mutant hematopoietic cells display metabolic alterations that can be targeted to treat myeloproliferative neoplasms. Blood 2019; 134:1832-1846. [PMID: 31511238 PMCID: PMC6872961 DOI: 10.1182/blood.2019000162] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 08/17/2019] [Indexed: 12/20/2022] Open
Abstract
Increased energy requirement and metabolic reprogramming are hallmarks of cancer cells. We show that metabolic alterations in hematopoietic cells are fundamental to the pathogenesis of mutant JAK2-driven myeloproliferative neoplasms (MPNs). We found that expression of mutant JAK2 augmented and subverted metabolic activity of MPN cells, resulting in systemic metabolic changes in vivo, including hypoglycemia, adipose tissue atrophy, and early mortality. Hypoglycemia in MPN mouse models correlated with hyperactive erythropoiesis and was due to a combination of elevated glycolysis and increased oxidative phosphorylation. Modulating nutrient supply through high-fat diet improved survival, whereas high-glucose diet augmented the MPN phenotype. Transcriptomic and metabolomic analyses identified numerous metabolic nodes in JAK2-mutant hematopoietic stem and progenitor cells that were altered in comparison with wild-type controls. We studied the consequences of elevated levels of Pfkfb3, a key regulatory enzyme of glycolysis, and found that pharmacological inhibition of Pfkfb3 with the small molecule 3PO reversed hypoglycemia and reduced hematopoietic manifestations of MPNs. These effects were additive with the JAK1/2 inhibitor ruxolitinib in vivo and in vitro. Inhibition of glycolysis by 3PO altered the redox homeostasis, leading to accumulation of reactive oxygen species and augmented apoptosis rate. Our findings reveal the contribution of metabolic alterations to the pathogenesis of MPNs and suggest that metabolic dependencies of mutant cells represent vulnerabilities that can be targeted for treating MPNs.
Collapse
Affiliation(s)
- Tata Nageswara Rao
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Nils Hansen
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Julian Hilfiker
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Shivam Rai
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Julia-Magdalena Majewska
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Danijela Leković
- Clinic of Hematology, Clinical Center of Serbia, Belgrade, Serbia
| | - Deniz Gezer
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | - Nicola Andina
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Serena Galli
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Teresa Cassel
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology and Markey Cancer Center, University of Kentucky, Lexington, KY
| | - Florian Geier
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | | | - Ronny Nienhold
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Hui Hao-Shen
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Christian Beisel
- Department of Biosystems Science and Engineering, ETH Zurich, Basel, Switzerland
| | - Serena Di Palma
- Functional Genomics Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Sarah Dimeloe
- Immunobiology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| | - Jonel Trebicka
- Department of Internal Medicine I, University of Bonn, Bonn, Germany
- European Foundation for the Study of Chronic Liver Failure, Barcelona, Spain
- Department of Gastroenterology, Odense Hospital, University of Southern Denmark, Odense, Denmark
- Institute for Bioengineering of Catalonia, Barcelona, Spain
| | - Dominik Wolf
- Internal Medicine V, Department of Hematology and Oncology, Medical University Innsbruck, Innsbruck, Austria
- Medical Clinic III for Oncology, Hematology, Immunoncology and Rheumatology, University Hospital Bonn, Bonn, Germany
| | - Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Teresa W-M Fan
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology and Markey Cancer Center, University of Kentucky, Lexington, KY
| | - Andrew N Lane
- Center for Environmental and Systems Biochemistry, Department of Toxicology and Cancer Biology and Markey Cancer Center, University of Kentucky, Lexington, KY
| | | | - Stefan Dirnhofer
- Institute of Pathology, University Hospital Basel, Basel, Switzerland
| | - Nicolaus Kröger
- Department of Stem Cell Transplantation, University Hospital Eppendorf, Hamburg, Germany
| | - Christoph Hess
- Immunobiology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
- Department of Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Thomas Radimerski
- Disease Area Oncology, Novartis Institutes for Biomedical Research, Basel, Switzerland; and
| | - Steffen Koschmieder
- Department of Hematology, Oncology, Hemostaseology, and Stem Cell Transplantation, Faculty of Medicine, RWTH Aachen University, Aachen, Germany
| | - Vladan P Čokić
- Institute for Medical Research, University of Belgrade, Belgrade, Serbia
| | - Radek C Skoda
- Experimental Hematology, Department of Biomedicine, University Hospital Basel and University of Basel, Basel, Switzerland
| |
Collapse
|
5
|
Daryadel A, Natale L, Seebeck P, Bettoni C, Schnitzbauer U, Gassmann M, Wagner CA. Elevated FGF23 and disordered renal mineral handling with reduced bone mineralization in chronically erythropoietin over-expressing transgenic mice. Sci Rep 2019; 9:14989. [PMID: 31628396 PMCID: PMC6802194 DOI: 10.1038/s41598-019-51577-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 09/09/2019] [Indexed: 12/22/2022] Open
Abstract
Fibroblast Growth Factor 23 (FGF23) is a phosphaturic factor causing increased renal phosphate excretion as well as suppression of 1,25 (OH)2-vitamin D3. Highly elevated FGF23 can promote development of rickets and osteomalacia. We and others previously reported that acute application of erythropoietin (EPO) stimulates FGF23 production. Considering that EPO is clinically used as chronic treatment against anemia, we used here the Tg6 mouse model that constitutively overexpresses human EPO in an oxygen-independent manner, to examine the consequences of long-term EPO therapy on mineral and bone metabolism. Six to eight weeks old female Tg6 mice showed elevated intact and C-terminal fragment of FGF23 but normal plasma levels of PTH, calcitriol, calcium and phosphate. Renal function showed moderate alterations with higher urea and creatinine clearance and mild albuminuria. Renal phosphate excretion was normal whereas mild hypercalciuria was found. Renal expression of the key proteins TRPV5 and calbindin D28k involved in active calcium reabsorption was reduced in Tg6 mice. Plasma levels of the bone turnover marker osteocalcin were comparable between groups. However, urinary excretion of deoxypyridinoline (DPD) was lower in Tg6 mice. MicroCT analysis showed reduced total, cortical, and trabecular bone mineral density in femora from Tg6 mice. Our data reveal that chronic elevation of EPO is associated with high FGF23 levels and disturbed mineral homeostasis resulting in reduced bone mineral density. These observations imply the need to study the impact of therapeutically applied EPO on bone mineralization in patients, especially those suffering from chronic kidney disease.
Collapse
Affiliation(s)
- Arezoo Daryadel
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,National Centre for Competence in Research NCCR "Kidney.CH", Zurich, Switzerland
| | - Luciano Natale
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Petra Seebeck
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,Zurich Integrative Rodent Physiology (ZIRP), University of Zurich, Zurich, Switzerland
| | - Carla Bettoni
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,National Centre for Competence in Research NCCR "Kidney.CH", Zurich, Switzerland
| | - Udo Schnitzbauer
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,National Centre for Competence in Research NCCR "Kidney.CH", Zurich, Switzerland
| | - Max Gassmann
- Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland.,Institute of Veterinary Physiology, University of Zurich, Zurich, Switzerland.,Universidad Peruana Cayetano Heredia (UPCH), Lima, Peru
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland. .,Zurich Center for Integrative Human Physiology (ZIHP), University of Zurich, Zurich, Switzerland. .,National Centre for Competence in Research NCCR "Kidney.CH", Zurich, Switzerland.
| |
Collapse
|
6
|
Gong XL, Gu XL, Chen YC, Zhu H, Xia ZN, Li JZ, Lu GC. Chronic preclinical safety evaluation of EPO-018B, a pegylated peptidic erythropoiesis-stimulating agent in monkeys and rats. Toxicol Appl Pharmacol 2016; 307:45-61. [PMID: 27457977 DOI: 10.1016/j.taap.2016.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 07/19/2016] [Accepted: 07/20/2016] [Indexed: 10/21/2022]
Abstract
EPO-018B, a synthetic peptide-based erythropoiesis stimulating agent (ESA), is mainly designed for treatment of anemia caused by chronic renal failure and chemotherapy against cancer. It overcomes the deficiencies of currently approved ESA, including the frequent administration of temperature-sensitive recombinant protein and anti-EPO antibody-mediated pure red cell aplasia (PRCA). This study was designed to evaluate the potential chronic toxicity of EPO-018B. Subcutaneous administration doses were designed as 0, 0.2, 1 and 10mg/kg for six months for 160 rats (20/gender/group) and 0, 0.3, 3 and 20mg/kg for nine months for 32 monkeys (4/gender/group) once every three weeks. The vehicles received the same volume of physiological saline injection. All animals survived to the scheduled necropsies after six weeks (for rats) and fourteen weeks (for monkeys) recovery period, except for the two high-dose female rats and two high-dose male monkeys, which were considered related to the increased RBCs, chronic blood hyperviscosity and chronic cardiac injury. EPO-018B is supposed to be subcutaneously injected once every month and the intended human therapeutic dose is 0.025mg/kg. The study findings at 0.2mg/kg for rats and 0.3mg/kg for monkeys were considered to be the study NOAEL (the no observed adverse effect level), which were more than ten times the intended human therapeutic dose. Higher doses caused adverse effects related to the liver toxicity, cardiotoxicity, appearance of neutralizing antibodies of EPO-018B and the decrease of serum glucose and cholesterol. Most treatment-induced effects were reversible or revealed ongoing recovery upon the discontinuation of treatment. The sequelae occurred in rats and monkeys were considered secondary to exaggerated pharmacology and would less likely occur in the intended patient population. As to the differences between human beings and animals, the safety of EPO-018B need to be further confirmed in the future clinical studies.
Collapse
Affiliation(s)
- Xue-Lian Gong
- Department of Hygiene and Toxicology, Second Military Medical University, Shanghai 200433, China
| | - Xiao-Lei Gu
- Department of Hygiene and Toxicology, Second Military Medical University, Shanghai 200433, China
| | - Yong-Chun Chen
- Department of Hygiene and Toxicology, Second Military Medical University, Shanghai 200433, China; Department of Pharmacy, No.422 Hospital, Zhanjiang 524005, China
| | - Hai Zhu
- Department of Hygiene and Toxicology, Second Military Medical University, Shanghai 200433, China
| | - Zhen-Na Xia
- Department of Hygiene and Toxicology, Second Military Medical University, Shanghai 200433, China
| | - Jian-Zhong Li
- Department of Biochemical Pharmacy, Second Military Medical University, Shanghai 200433, China.
| | - Guo-Cai Lu
- Department of Hygiene and Toxicology, Second Military Medical University, Shanghai 200433, China.
| |
Collapse
|
7
|
Frey H, Moreth K, Hsieh LTH, Zeng-Brouwers J, Rathkolb B, Fuchs H, Gailus-Durner V, Iozzo RV, de Angelis MH, Schaefer L. A novel biological function of soluble biglycan: Induction of erythropoietin production and polycythemia. Glycoconj J 2016; 34:393-404. [DOI: 10.1007/s10719-016-9722-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/21/2016] [Accepted: 08/05/2016] [Indexed: 11/29/2022]
|
8
|
Deligiannis A, Björnstad H, Carre F, Heidbüchel H, Kouidi E, Panhuyzen-Goedkoop NM, Pigozzi F, Schänzer W, Vanhees L. ESC Study Group of Sports Cardiology Position Paper on adverse cardiovascular effects of doping in athletes. ACTA ACUST UNITED AC 2016; 13:687-94. [PMID: 17001206 DOI: 10.1097/01.hjr.0000224482.95597.7a] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The use of doping substances and methods is extensive not only among elite athletes, but also among amateur and recreational athletes. Many types of drugs are used by athletes to enhance performance, to reduce anxiety, to increase muscle mass, to reduce weight or to mask the use of other drugs during testing. However, the abuse of doping substances and methods has been associated with the occurrence of numerous health side-effects. The adverse effects depend on the type of the consumed drug, as well as the amount and duration of intake and the sensitivity of the body, since there is a large inter-individual variability in responses to a drug. Usually the doses used in sports are much higher than those used for therapeutic purposes and the use of several drugs in combination is frequent, leading to higher risk of side-effects. Among biomedical side-effects of doping, the cardiovascular ones are the most deleterious. Myocardial infarction, hyperlipidemia, hypertension, thrombosis, arrythmogenesis, heart failure and sudden cardiac death have been noted following drug abuse. This paper reviews the literature on the adverse cardiovascular effects after abuse of prohibited substances and methods in athletes, aiming to inform physicians, trainers and athletes and to discourage individuals from using drugs during sports.
Collapse
Affiliation(s)
- Asterios Deligiannis
- Laboratory of Sports Medicine, Aristotle University, Thessaloniki, Greece. stergios@ med.auth.gr
| | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Menuet C, Khemiri H, de la Poëze d'Harambure T, Gestreau C. Polycythemia and high levels of erythropoietin in blood and brain blunt the hypercapnic ventilatory response in adult mice. Am J Physiol Regul Integr Comp Physiol 2016; 310:R979-91. [PMID: 26936784 DOI: 10.1152/ajpregu.00474.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 02/26/2016] [Indexed: 11/22/2022]
Abstract
Changes in arterial Po2, Pco2, and pH are the strongest stimuli sensed by peripheral and central chemoreceptors to adjust ventilation to the metabolic demand. Erythropoietin (Epo), the main regulator of red blood cell production, increases the hypoxic ventilatory response, an effect attributed to the presence of Epo receptors in both carotid bodies and key brainstem structures involved in integration of peripheral inputs and control of breathing. However, it is not known whether Epo also has an effect on the hypercapnic chemoreflex. In a first attempt to answer this question, we tested the hypothesis that Epo alters the ventilatory response to increased CO2 levels. Basal ventilation and hypercapnic ventilatory response (HCVR) were recorded from control mice and from two transgenic mouse lines constitutively expressing high levels of human Epo in brain only (Tg21) or in brain and plasma (Tg6), the latter leading to polycythemia. To tease apart the potential effects of polycythemia and levels of plasma Epo in the HCVR, control animals were injected with an Epo analog (Aranesp), and Tg6 mice were treated with the hemolytic agent phenylhydrazine after splenectomy. Ventilatory parameters measured by plethysmography in conscious mice were consistent with data from electrophysiological recordings in anesthetized animals and revealed a blunted HCVR in Tg6 mice. Polycythemia alone and increased levels of plasma Epo blunt the HCVR. In addition, Tg21 mice with an augmented level of cerebral Epo also had a decreased HCVR. We discuss the potential implications of these findings in several physiopathological conditions.
Collapse
|
10
|
Oikonomidou PR, Casu C, Yang Z, Crielaard B, Shim JH, Rivella S, Vogiatzi MG. Polycythemia is associated with bone loss and reduced osteoblast activity in mice. Osteoporos Int 2016; 27:1559-1568. [PMID: 26650379 PMCID: PMC5319412 DOI: 10.1007/s00198-015-3412-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Accepted: 11/05/2015] [Indexed: 01/19/2023]
Abstract
UNLABELLED Increased fragility has been described in humans with polycythemia vera (PV). Herein, we describe an osteoporotic phenotype associated with decreased osteoblast activity in a mouse model of PV and another mouse of polycythemia and elevated circulating erythropoietin (EPO). Our results are important for patients with PV or those treated with recombinant EPO (rEPO). INTRODUCTION PV and other myeloproliferative syndromes have been recently associated with an increased risk for fractures. However, the presence of osteoporosis in these patients has not been well documented. EPO, a hormone primarily known to stimulate erythropoiesis, has been shown recently to regulate bone homeostasis in mice. The aim of this study was to examine the bone phenotype of a mouse model of PV and compare it to that of animals with polycythemia caused by elevated circulating EPO. METHODS Bone mass and remodeling were evaluated by micro-computed tomography and histomorphometry. The JAK2(V617F) knock-in mouse, a model of human PV, manifests polycythemia and low circulating EPO levels. Results from this mouse were compared to wild type (wt) controls and the tg6 transgenic mouse that shows polycythemia caused by increased constitutive expression of EPO. RESULTS Compared to wt, both JAK2(V617F) and tg6 mice had a decrease in trabecular bone mass. Tg6 mice showed an additional modest decrease in cortical thickness and cortical bone volume per tissue volume (P < 0.01) suggesting a more severe bone phenotype than JAK2(V617F). Decreased osteoblast numbers and bone formation along with normal osteoclast numbers and activity were found in both mice. CONCLUSIONS This study indicates that PV is associated with low bone mass and decreased osteoblast activity in mice. Our results support future studies of osteoporosis in affected humans. Polycythemia caused by chronically elevated circulating EPO also results in bone loss, and implications on patients treated with rEPO should be evaluated.
Collapse
Affiliation(s)
- P R Oikonomidou
- Division of Pediatric Endocrinology, Weill Cornell Medical College, New York, NY, USA.
- Division of Hematology, Children's Hospital of Philadelphia, Abramson Research Center, 3615 Civic Center Blvd., Room 309 F, Philadelphia, PA, 19104, USA.
| | - C Casu
- Division of Pediatric Hematology/Oncology, Weill Cornell Medical College, New York, NY, USA
- Division of Hematology, Children's Hospital of Philadelphia, Abramson Research Center, 3615 Civic Center Blvd., Room 309 F, Philadelphia, PA, 19104, USA
| | - Z Yang
- Department of Medicine, Cancer Center, Weill Cornell Medical College, Belfer Research Building, 413 East 69th Street, 13th Floor, New York, NY,, 10021, USA
| | - B Crielaard
- Division of Pediatric Hematology/Oncology, Weill Cornell Medical College, New York, NY, USA
- Department of Polymer Chemistry and Bioengineering, Zernike Institute for Advanced Materials, University of Groningen, Nijenborgh 4, 9747 AG, Groningen, Netherlands
| | - J H Shim
- Department of Pathology and Laboratory medicine, Weill Cornell Medical College, 1300 York Avenue, E-904, New York, NY,, 10065, USA
| | - S Rivella
- Division of Pediatric Hematology/Oncology, Weill Cornell Medical College, New York, NY, USA
- Division of Hematology, Children's Hospital of Philadelphia, Abramson Research Center, 3615 Civic Center Blvd., Room 316 B, Philadelphia, PA, 19104, USA
| | - M G Vogiatzi
- Division of Pediatric Endocrinology, Weill Cornell Medical College, New York, NY, USA
- Division of Endocrinology, Children's Hospital of Philadelphia, 3401 Civic Center Bvld., Philadelphia, PA, 19104, USA
| |
Collapse
|
11
|
Recombinant Human Erythropoietin Protects Myocardial Cells from Apoptosis via the Janus-Activated Kinase 2/Signal Transducer and Activator of Transcription 5 Pathway in Rats with Epilepsy. Curr Ther Res Clin Exp 2015; 77:90-8. [PMID: 26649078 PMCID: PMC4644243 DOI: 10.1016/j.curtheres.2015.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/28/2015] [Indexed: 12/19/2022] Open
Abstract
OBJECTIVE To investigate the potential mechanisms underlying the protective effects of recombinant human erythropoietin (rhEPO) and carbamylated EPO (CEPO) against myocardial cell apoptosis in epilepsy. METHODS Rats were given an intra-amygdala injection of kainic acid to induce epilepsy. Groups of rats were treated with rhEPO or CEPO before induction of epilepsy, whereas additional rats were given a caudal vein injection of AG490, a selective inhibitor of Janus kinase 2 (JAK2). At different time points after seizure onset, electroencephalogram changes were recorded, and myocardium samples were taken for the detection of myocardial cell apoptosis and expression of JAK2, signal transducer and activator of transcription 5 (STAT5), caspase-3, and bcl-xl mRNAs and proteins. RESULTS Induction of epilepsy significantly enhanced myocardial cell apoptosis and upregulated the expression of caspase-3 and bcl-xl proteins and JAK2 and STAT5a at both the mRNA and protein levels. Pretreatment with either rhEPO or CEPO reduced the number of apoptotic cells, upregulated bcl-xl expression, and downregulated caspase-3 expression in the myocardium of epileptic rats. Both myocardial JAK2 and STAT5a mRNAs, as well as phosphorylated species of JAK2 and STAT5a, were upregulated in epileptic rats in response to rhEPO-but not to CEPO-pretreatment. AG490 treatment increased apoptosis, upregulated caspase-3 protein expression, and downregulated bcl-xl protein expression in the myocardium of epileptic rats. CONCLUSIONS These results indicate that myocardial cell apoptosis may contribute to myocardial injury in epilepsy. EPO protects myocardial cells from apoptosis via the JAK2/STAT5 pathway in rats with experimental epilepsy, whereas CEPO exerts antiapoptotic activity perhaps via a pathway independent of JAK2/STAT5 signaling.
Collapse
|
12
|
Kittur FS, Arthur E, Nguyen M, Hung CY, Sane DC, Xie J. Two-step purification procedure for recombinant human asialoerythropoietin expressed in transgenic plants. Int J Biol Macromol 2015; 72:1111-6. [PMID: 25450830 PMCID: PMC4260996 DOI: 10.1016/j.ijbiomac.2014.10.033] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 10/13/2014] [Accepted: 10/15/2014] [Indexed: 12/19/2022]
Abstract
Asialoerythropoietin (asialo-EPO) is a desialylated form of human glycoprotein hormone erythropoietin (EPO), which has been reported to be neuro-, cardio-, and renoprotective in animal models of organ injuries. Since the current method of production of asialo-EPO from mammalian cell-made recombinant human EPO (rhuEPO(M)) by enzymatic desialylation is not commercially viable, we and others used plant-based expression systems to produce recombinant human asialo-EPO (asialo-rhuEPO(P)). Despite achieving high expression levels in plants, its purification from plant extracts has remained a greater challenge, which has prevented studying its tissue-protective effects and translating it into clinical practice. In this study, a procedure was developed to purify asialo-rhuEPO(P) from transgenic tobacco leaf tissues in two steps: ion-exchange chromatography based on its high pI (8.75) to separate it from acidic plant proteins, and immunoaffinity chromatography to obtain pure asialo-rhuEPO(P). Using this process, up to 31% of the asialo-rhuEPO(P) could be recovered to near homogeneity from plant extracts. This work demonstrates that asialo-rhuEPO(P) expressed in tobacco plants could be purified in high yield and purity using minimal steps, which might be suitable for scale-up. Furthermore, the ion-exchange chromatography step together with the use of protein-specific antibody column could be used to purify a wide variety of basic recombinant proteins from transgenic leaf tissues.
Collapse
Affiliation(s)
- Farooqahmed S Kittur
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA
| | - Elena Arthur
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA
| | - Maikhanh Nguyen
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA
| | - Chiu-Yueh Hung
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA
| | - David C Sane
- Carilion Clinic and Virginia Tech Carilion School of Medicine, Roanoke, VA 24014, USA
| | - Jiahua Xie
- Department of Pharmaceutical Sciences, Biomanufacturing Research Institute & Technology Enterprise, North Carolina Central University, Durham, NC 27707, USA.
| |
Collapse
|
13
|
Deindl P, Klar M, Drews D, Cremer M, Gammella E, Gassmann M, Dame C. Mice over-expressing human erythropoietin indicate that erythropoietin enhances expression of its receptor via up-regulated Gata1 and Tal1. Haematologica 2014; 99:e205-7. [PMID: 25085352 DOI: 10.3324/haematol.2014.104844] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Philipp Deindl
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany Department of Neonatology and Pediatric Intensive Care Medicine, University Medical Center Hamburg-Eppendorf, Germany
| | - Martin Klar
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - David Drews
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - Malte Cremer
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| | - Elena Gammella
- Department of Biomedical Sciences for Health, University of Milano, Italyand
| | - Max Gassmann
- Institute of Veterinary Physiology and Zurich Center for Human Integrative Physiology (ZIHP), University of Zürich, Switzerland
| | - Christof Dame
- Department of Neonatology, Charité - Universitätsmedizin Berlin, Germany
| |
Collapse
|
14
|
Schwartzenberg S, Ben-Shoshan J, Keren G, George J. The role of erythropoietin in myocardial protection: potential mechanisms and applications. Expert Rev Cardiovasc Ther 2014; 4:41-50. [PMID: 16375627 DOI: 10.1586/14779072.4.1.41] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The glycoprotein erythropoietin was originally discovered as a principal regulator that promotes the survival, proliferation and differentiation of erythroid progenitor cells. Despite potentially detrimental effects, such as increased blood pressure and hyperviscosity, recombinant human erythropoietin has been demonstrated to be a safe drug, as millions of anemia sufferers have received it over the last decade as a form of treatment. Recently, erythropoietin receptors have been discovered in a variety of tissues, including the cardiovascular system, and erythropoietin has been demonstrated to have a beneficial effect in congestive heart failure patients with anemia. The purpose of this review is to summarize the pleiotropic cardioprotective effects of erythropoietin in the cardiovascular system and to evaluate its potential role as a biomarker in these disorders.
Collapse
|
15
|
Kim BJ, Kim DW, Kim SH, Cho JH, Lee HJ, Park DY, Park SR, Choi BH, Min BH. Establishment of a reliable and reproducible murine osteoarthritis model. Osteoarthritis Cartilage 2013; 21:2013-20. [PMID: 24120491 DOI: 10.1016/j.joca.2013.09.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Revised: 09/11/2013] [Accepted: 09/28/2013] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Many osteoarthritis (OA) models have been developed in mice to understand OA progression and evaluate new OA therapies. However, the individual variation of the joint lesions remains a critical problem in most of the current OA models. We established an OA model in C57BL/6 mice that is more reproducible and amenable to therapeutic intervention by controlling their movement. DESIGN OA was induced in 9-week-old C57BL/6 mice by destabilizing the medial meniscus. The mice were then raised in the standard cage for free movement or in a confined cage customized to restrict movement. Mice in the confined cage were subjected to no exercise or exercise of 400, 800, and 1200 m/day. RESULTS OA lesions of mice in the confined cage were more severe in the exercise group and showed much less variation. However, the patterns of OA lesions over time were quite different depending on the amount of daily exercise; the patterns increased linearly until 8 weeks in 400 m/day exercise group, but showed plateauing after 4 weeks in 800 m/day and 1200 m/day groups. The validity of our novel OA model with movement control was proven by successfully discriminating the therapeutic effect of hyaluronic acid (HA) in histological scores, while the OA model using standard caging showed a statistically insignificant difference. CONCLUSION The mouse OA model using the confine cage and enforced periodic exercise of mice is more reproducible and reliable than standard caging methods.
Collapse
Affiliation(s)
- B J Kim
- Department of Molecular Science & Technology, Ajou University, Suwon, South Korea
| | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Constitutive excessive erythrocytosis causes inflammation and increased vascular permeability in aged mouse brain. Brain Res 2013; 1531:48-57. [PMID: 23892106 DOI: 10.1016/j.brainres.2013.07.033] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 07/03/2013] [Accepted: 07/19/2013] [Indexed: 12/16/2022]
Abstract
Excessive erythrocytosis results in severely increased blood viscosity that may compromise the vascular endothelium. Using our transgenic mouse model of excessive erythrocytosis we previously showed that despite altered brain endothelial cell morphology and an activated vasculature, brain vascular integrity was largely maintained up to 4-5 months of age. We now present data showing that persistent long-term damage of the vascular wall during the later stages of adulthood (9-12 months) results in a chronic detrimental inflammatory phenotype and increased vessel permeability that likely contributes to the reduced life span of our erythropoietin overexpressing transgenic mouse. In aged transgenic animals inflammatory cells were detected in brain tissue and elevated RNA and protein levels of inflammatory markers such as IL-6 and TNFα were observed in both brain tissue and blood plasma. Additionally, increased expression of p53 and other pro-apoptotic markers, as well as decreased Bcl-xL expression in the brain vasculature, indicated ongoing cell death within the vascular compartment. Finally, abnormally elevated vascular permeability in all organs was detected in correlation with decreased expression of the tight junction protein occludin and the adherens junction protein β-catenin in brain. Thus chronic erythrocytosis results in sustained activation of inflammatory pathways, vascular dysfunction and blood-brain barrier disruption.
Collapse
|
17
|
HIF-1α is a protective factor in conditional PHD2-deficient mice suffering from severe HIF-2α-induced excessive erythropoiesis. Blood 2012; 121:1436-45. [PMID: 23264599 DOI: 10.1182/blood-2012-08-449181] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Erythropoiesis must be tightly balanced to guarantee adequate oxygen delivery to all tissues in the body. This process relies predominantly on the hormone erythropoietin (EPO) and its transcription factor hypoxia inducible factor (HIF). Accumulating evidence suggests that oxygen-sensitive prolyl hydroxylases (PHDs) are important regulators of this entire system. Here, we describe a novel mouse line with conditional PHD2 inactivation (cKO P2) in renal EPO producing cells, neurons, and astrocytes that displayed excessive erythrocytosis because of severe overproduction of EPO, exclusively driven by HIF-2α. In contrast, HIF-1α served as a protective factor, ensuring survival of cKO P2 mice with HCT values up to 86%. Using different genetic approaches, we show that simultaneous inactivation of PHD2 and HIF-1α resulted in a drastic PHD3 reduction with consequent overexpression of HIF-2α-related genes, neurodegeneration, and lethality. Taken together, our results demonstrate for the first time that conditional loss of PHD2 in mice leads to HIF-2α-dependent erythrocytosis, whereas HIF-1α protects these mice, providing a platform for developing new treatments of EPO-related disorders, such as anemia.
Collapse
|
18
|
Vautier J, El Tannir El Tayara N, Walczak C, Mispelter J, Volk A. Radial multigradient-echo DCE-MRI for 3DKtransmapping with individual arterial input function measurement in mouse tumor models. Magn Reson Med 2012; 70:823-8. [DOI: 10.1002/mrm.24504] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 08/08/2012] [Accepted: 08/28/2012] [Indexed: 11/08/2022]
Affiliation(s)
- Julien Vautier
- Institut Curie; Research Center; Orsay France
- Institut national de la santé et de la recherche médicale (INSERM); U759 Orsay France
- Université Paris Sud; Orsay France
| | - Nadine El Tannir El Tayara
- Institut Curie; Research Center; Orsay France
- Institut national de la santé et de la recherche médicale (INSERM); U759 Orsay France
| | - Christine Walczak
- Institut Curie; Research Center; Orsay France
- Institut national de la santé et de la recherche médicale (INSERM); U759 Orsay France
| | - Joël Mispelter
- Institut Curie; Research Center; Orsay France
- Institut national de la santé et de la recherche médicale (INSERM); U759 Orsay France
| | - Andreas Volk
- Institut Curie; Research Center; Orsay France
- Institut national de la santé et de la recherche médicale (INSERM); U759 Orsay France
| |
Collapse
|
19
|
Mille-Hamard L, Billat VL, Henry E, Bonnamy B, Joly F, Benech P, Barrey E. Skeletal muscle alterations and exercise performance decrease in erythropoietin-deficient mice: a comparative study. BMC Med Genomics 2012; 5:29. [PMID: 22748015 PMCID: PMC3473259 DOI: 10.1186/1755-8794-5-29] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 06/21/2012] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Erythropoietin (EPO) is known to improve exercise performance by increasing oxygen blood transport and thus inducing a higher maximum oxygen uptake (VO2max). Furthermore, treatment with (or overexpression of) EPO induces protective effects in several tissues, including the myocardium. However, it is not known whether EPO exerts this protective effect when present at physiological levels. Given that EPO receptors have been identified in skeletal muscle, we hypothesized that EPO may have a direct, protective effect on this tissue. Thus, the objectives of the present study were to confirm a decrease in exercise performance and highlight muscle transcriptome alterations in a murine EPO functional knock-out model (the EPO-d mouse). METHODS We determined VO2max peak velocity and critical speed in exhaustive runs in 17 mice (9 EPO-d animals and 8 inbred controls), using treadmill enclosed in a metabolic chamber. Mice were sacrificed 24h after a last exhaustive treadmill exercise at critical speed. The tibialis anterior and soleus muscles were removed and total RNA was extracted for microarray gene expression analysis. RESULTS The EPO-d mice's hematocrit was about 50% lower than that of controls (p<0.05) and their performance level was about 25% lower (p<0.001). A total of 1583 genes exhibited significant changes in their expression levels. However, 68 genes were strongly up-regulated (normalized ratio>1.4) and 115 were strongly down-regulated (normalized ratio<0.80). The transcriptome data mining analysis showed that the exercise in the EPO-d mice induced muscle hypoxia, oxidative stress and proteolysis associated with energy pathway disruptions in glycolysis and mitochondrial oxidative phosphorylation. CONCLUSIONS Our results showed that the lack of functional EPO induced a decrease in the aerobic exercise capacity. This decrease was correlated with the hematocrit and reflecting poor oxygen supply to the muscles. The observed alterations in the muscle transcriptome suggest that physiological concentrations of EPO exert both direct and indirect muscle-protecting effects during exercise. However, the signaling pathway involved in these protective effects remains to be described in detail.
Collapse
Affiliation(s)
- Laurence Mille-Hamard
- Unité de Biologie Intégrative des Adaptations à l'Exercice - INSERM 902, Genopole, F-91058, Evry, France.
| | | | | | | | | | | | | |
Collapse
|
20
|
Yun SJ, Naidansuren P, Sim BW, Park JJ, Park CW, Nanjidsuren T, Kang MH, Hwang SY, Yoon JT, Min KS. Aberrant phenotypes of transgenic mice expressing dimeric human erythropoietin. Reprod Biol Endocrinol 2012; 10:6. [PMID: 22284751 PMCID: PMC3284390 DOI: 10.1186/1477-7827-10-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 01/27/2012] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Dimeric human erythropoietin (dHuEPO) peptides are reported to exhibit significantly higher biological activity than the monomeric form of recombinant EPO. The objective of this study was to produce transgenic (tg) mice expressing dHuEPO and to investigate the characteristics of these mice. METHODS A dHuEPO-expressing vector under the control of the goat beta-casein promoter, which produced a dimer of human EPO molecules linked by a 2-amino acid peptide linker (Asp-Ile), was constructed and injected into 1-cell fertilized embryos by microinjection. Mice were screened using genomic DNA samples obtained from tail biopsies. Blood samples were obtained by heart puncture using heparinized tubes, and hematologic parameters were assessed. Using the microarray analysis tool, we analyzed differences in gene expression in the spleens of tg and control mice. RESULTS A high rate of spontaneous abortion or death of the offspring was observed in the recipients of dHuEPO embryos. We obtained 3 founder lines (#4, #11, and #47) of tg mice expressing the dHuEPO gene. However, only one founder line showed stable germline integration and transmission, subsequently establishing the only transgenic line (#11). We obtained 2 F1 mice and 3 F2 mice from line #11. The dHuEPO protein could not be obtained because of repeated spontaneous abortions in the tg mice. Tg mice exhibited symptoms such as short lifespan and abnormal blood composition. The red blood cell count, white blood cell count, and hematocrit levels in the tg mice were remarkably higher than those in the control mice. The spleens of the tg mice (F1 and F2 females) were 11- and -21-fold larger than those of the control mice. Microarray analysis revealed 2,672 spleen-derived candidate genes; more genes were downregulated than upregulated (849/764). Reverse transcriptase-polymerase chain reaction (RT-PCR) and quantitative real-time PCR (qRT-PCR) were used for validating the results of the microarray analysis of mRNA expression. CONCLUSIONS In conclusion, dHuEPO tg mice caused excessive erythrocytosis that led to abnormal blood composition, short lifespan, and abnormal splenomegaly. Further, we identified 2,672 genes associated with splenomegaly by microarray analysis. These results could be useful in the development of dHuEPO-producing tg animals.
Collapse
Affiliation(s)
- Seong-Jo Yun
- Animal Biotechnology, Graduate School of Bio & Information Technology, Institute of Genetic Engineering, Hankyong National University, Ansung 456-749, Korea
| | | | | | | | | | | | | | | | | | | |
Collapse
|
21
|
Coglianese EE, Qureshi MM, Vasan RS, Wang TJ, Moore LL. Usefulness of the blood hematocrit level to predict development of heart failure in a community. Am J Cardiol 2012; 109:241-5. [PMID: 21996141 DOI: 10.1016/j.amjcard.2011.08.037] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Revised: 08/30/2011] [Accepted: 08/30/2011] [Indexed: 10/16/2022]
Abstract
Current data suggest that increases in hemoglobin may decrease nitric oxide and adversely affect vascular function. In the preclinical setting, these changes could precipitate the development of heart failure (HF). We hypothesized that higher hematocrit (HCT) would be associated with an increased incidence of new-onset HF in the community. We evaluated 3,523 participants (59% women) from the Framingham Heart Study who were 50 to 65 years old and free of HF. Participants were followed prospectively until an HF event, death, or the end of 20 years of follow up. HCT was subdivided into 4 gender-specific categories (women: HCT 36.0 to 40.0, 40.1 to 42.0, 42.1 to 45.0, >45.0; men: 39.0 to 44.0, 44.1 to 45.0, 45.1 to 49.0, >49.0). Gender-pooled multivariable Cox proportional hazards models were used to estimate the association of HCT with incident HF, adjusting for clinical risk factors. During the follow-up period (61,417 person-years), 217 participants developed HF (100 events in women). There was a linear increase in risk of HF across the 4 HCT categories (p for trend = 0.002). Hazards ratios for HF in the low-normal, normal, and high HCT categories were 1.27 (95% confidence interval 0.82 to 1.97), 1.47 (1.01 to 2.15), and 1.78 (1.15 to 2.75), respectively, compared to the lowest HCT category (p for trend <0.0001). Adjustment for interim development of other cardiovascular diseases and restriction of the sample to nonsmokers did not alter the results. In conclusion, higher levels of HCT, even within the normal range, were associated with an increased risk of developing HF in this long-term follow-up study.
Collapse
|
22
|
Richter V, Savery MD, Gassmann M, Baum O, Damiano ER, Pries AR. Excessive erythrocytosis compromises the blood-endothelium interface in erythropoietin-overexpressing mice. J Physiol 2011; 589:5181-92. [PMID: 21859826 DOI: 10.1113/jphysiol.2011.209262] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Elevated systemic haematocrit (Hct) increases risk of cardiovascular disorders, such as stroke and myocardial infarction. One possible pathophysiological mechanism could be a disturbance of the blood-endothelium interface. It has been shown that blood interacts with the endothelial surface via a thick hydrated macromolecular layer (the 'glycocalyx', or 'endothelial surface layer'--ESL), modulating various biological processes, including inflammation, permeability and atherosclerosis. However, the consequences of elevated Hct on the functional properties of this interface are incompletely understood. Thus, we combined intravital microscopy of an erythropoietin overexpressing transgenic mouse line (tg6) with excessive erythrocytosis (Hct 0.85), microviscometric analysis of haemodynamics, and a flow simulation model to assess the effects of elevated Hct on glycocalyx/ESL thickness and flow resistance. We show that the glycocalyx/ESL is nearly abolished in tg6 mice (thickness: wild-type control: 0.52 μm; tg6: 0.13 μm; P < 0.001). However, the corresponding reduction in network flow resistance contributes <20% to the maintenance of total peripheral resistance observed in tg6 mice. This suggests that the pathological effects of elevated Hct in these mice, and possibly also in polycythaemic humans, may relate to biological corollaries of a reduced ESL thickness and the consequent alteration in the blood-endothelium interface, rather than to an increase of flow resistance.
Collapse
|
23
|
Sahinarslan A, Yalcin R, Kocaman SA, Ercin U, Tanalp AC, Topal S, Bukan N, Boyaci B, Cengel A. The relationship of serum erythropoietin level with coronary collateral grade. Can J Cardiol 2011; 27:589-95. [PMID: 21775099 DOI: 10.1016/j.cjca.2011.04.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Revised: 04/01/2011] [Accepted: 04/01/2011] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND Erythropoietin has been shown to induce neovascularization and protect against ischemic vascular injury. We investigated whether a higher serum erythropoietin (EPO) level is related to better coronary collateral vessel grade. METHODS Ninety-nine patients with stable angina pectoris who have at least 1 coronary stenosis of equal to or greater than 70% at coronary angiography were prospectively enrolled. Serum EPO and vascular endothelial growth factor (VEGF) levels were studied. Coronary collateral degree was graded according to the Rentrop method. Patients with grade 2-3 collateral degree were included in the good collateral group and formed Group I. The patients with grade 0-1 collateral degree were included in the poor collateral group and formed Group II. RESULTS The serum EPO level was significantly higher in the good collateral group (17.3 ± 9.3 mU/mL vs 11.7 ± 5.0 mU/mL; P < 0.001). There was also a positive correlation between serum EPO level and Rentrop score (r = 0.39; P < 0.001). In multivariate analysis, serum EPO level (odds ratio [OR] 1.336; 95% confidence interval [CI], 1.120-1.593; P = 0.001), oxygen saturation (OR 0.638; 95% CI, 0.422-0.963; P = 0.033) and presence of chronic total occlusion (CTO) (OR 26.7; 95% CI, 3.874-184.6; P = 0.001) were independently related to well-developed coronary collaterals. CONCLUSIONS Higher serum EPO level is related to better coronary collateral development. Erythropoietin may have a positive effect on the development of collaterals and may provide a new agent for the treatment strategies to enhance coronary collateral vessel development.
Collapse
Affiliation(s)
- Asife Sahinarslan
- Department of Cardiology, Gazi University, School of Medicine, Ankara, Turkey.
| | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Mattio M, Ceaglio N, Oggero M, Perotti N, Amadeo I, Orozco G, Forno G, Kratje R, Etcheverrigaray M. Isolation and characterization of a subset of erythropoietin glycoforms with cytoprotective but minimal erythropoietic activity. Biotechnol Prog 2011; 27:1018-28. [DOI: 10.1002/btpr.633] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 04/06/2011] [Indexed: 12/20/2022]
|
25
|
Quarti A, Oggianu A, Soura E, Colaneri M, Colonna PL, Pozzi M. Brachial Arteriovenous Fistula in Patients with Cavopulmonary Connection and Poor Ventricular Function: A Bridge to Fontan Operation. J Card Surg 2011; 26:415-9. [DOI: 10.1111/j.1540-8191.2011.01252.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
26
|
Gassmann M, Pfistner C, Doan VD, Vogel J, Soliz J. Impaired ventilatory acclimatization to hypoxia in female mice overexpressing erythropoietin: unexpected deleterious effect of estradiol in carotid bodies. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1511-20. [DOI: 10.1152/ajpregu.00205.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Apart from enhancing the production of red blood cells, erythropoietin (Epo) alters the ventilatory response when oxygen supply is reduced. We recently demonstrated that Epo's beneficial effect on the ventilatory response to acute hypoxia is sex dependent, with female mice being better able to cope with reduced oxygenation. In the present work, we hypothesized that ventilatory acclimatization to chronic hypoxia (VAH) in transgenic female mice (Tg6) harboring high levels of Epo in the brain and blood will also be improved compared with wild-type (WT) animals. Surprisingly, VAH was blunted in Tg6 female mice. To define whether this phenomenon had a central (brain stem respiratory centers) and/or peripheral (carotid bodies) origin, a bilateral transection of carotid sinus nerve (chemodenervation) was performed. This procedure allowed the analysis of the central response in the absence of carotid body information. Interestingly, chemodenervation restored the VAH in Tg6 mice, suggesting that carotid bodies were responsible for the blunted response. Coherently with this observation, the sensitivity to oxygen alteration in arterial blood (Dejour test) after chronic hypoxia was lower in transgenic carotid bodies compared with the WT control. As blunted VAH occurred in female but not male transgenic mice, the involvement of sex female steroids was obvious. Indeed, measurement of sexual female hormones revealed that the estradiol serum level was 4 times higher in transgenic mice Tg6 than in WT animals. While ovariectomy decreased VAH in WT females, this treatment restored VAH in Tg6 female mice. In line with this observation, injections of estradiol in ovariectomized Tg6 females dramatically reduced the VAH. We concluded that during chronic hypoxia, estradiol in carotid bodies suppresses the Epo-mediated elevation of ventilation. Considering the increased application of recombinant Epo for a variety of disorders, our data imply the need to take the patient's hormonal status into consideration.
Collapse
Affiliation(s)
- Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| | - Christine Pfistner
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| | - Van Diep Doan
- Unité de Recherche en Périnatalogie, Centre Hospitalier Universitaire de Québec, Hôpital Saint-François d'Assise, Département de Pédiatrie, Université Laval, Québec, Canada
| | - Johannes Vogel
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| | - Jorge Soliz
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich, Switzerland; and
| |
Collapse
|
27
|
Gorr T, Wichmann D, Hu J, Hermes‐Lima M, Welker A, Terwilliger N, Wren J, Viney M, Morris S, Nilsson G, Deten A, Soliz J, Gassmann M. Hypoxia Tolerance in Animals: Biology and Application. Physiol Biochem Zool 2010; 83:733-52. [DOI: 10.1086/648581] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
28
|
Piloto N, Teixeira HM, Teixeira-Lemos E, Parada B, Garrido P, Sereno J, Pinto R, Carvalho L, Costa E, Belo L, Santos-Silva A, Teixeira F, Reis F. Erythropoietin promotes deleterious cardiovascular effects and mortality risk in a rat model of chronic sports doping. Cardiovasc Toxicol 2010; 9:201-10. [PMID: 19859831 DOI: 10.1007/s12012-009-9054-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Athletes who abuse recombinant human erythropoietin (rhEPO) consider only the benefit to performance and usually ignore the potential short and long-term liabilities. Elevated haematocrit and dehydratation associated with intense exercise may reveal undetected cardiovascular risk, but the mechanisms underlying it remain to be fully explained. This study aimed to evaluate the cardiovascular effects of rhEPO in rats under chronic aerobic exercise. A ten week protocol was performed in four male Wistar rat groups: control--sedentary; rhEPO--50 IU kg(-1), 3 times/wk; exercised (EX)--swimming for 1 h, 3 times/wk; EX + rhEPO. One rat of the EX + rhEPO group suffered a sudden death episode during the week 8. rhEPO in trained rats promoted erythrocyte count increase, hypertension, heart hypertrophy, sympathetic and serotonergic overactivation. The suddenly died rat's tissues presented brain with vascular congestion; left ventricular hypertrophy, together with a "cardiac-liver", suggesting the hypothesis of heart failure as cause of sudden death. In conclusion, rhEPO doping in rats under chronic exercise promotes not only the expected RBC count increment, suggesting hyperviscosity, but also other serious deleterious cardiovascular and thromboembolic modifications, including mortality risk, which might be known and assumed by all sports authorities, including athletes and their physicians.
Collapse
Affiliation(s)
- Nuno Piloto
- Institute of Pharmacology & Experimental Therapeutics, IBILI, Medicine Faculty, Sub-Unit 1 (Polo III), Coimbra University, 3004-504, Coimbra, Portugal
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
29
|
Abstract
Chronic Mountain Sickness (CMS) is an important high-altitude (HA) pathology in most mountainous regions of the world. Although its most characteristic sign is excessive erytrocytosis (EE), in the more severe stages of the disease, high-altitude pulmonary hypertension (HAPH), with remodeling of pulmonary arterioles and right ventricular enlargement is commonly found. The degree of ventricular hypertrophy depends on the vasoconstrictor pulmonary response, the intensity of vascular resistance and the level of altitude, and therefore on the degree of hypoxemia. This chapter briefly summarizes the existing data regarding the clinical and pathophysiological features of the cardiopulmonary system in CMS, with emphasis in findings from research in the Andes. The literature shows variability in cardiac output values in CMS, which might be related to the degree of EE. Recent findings have shown that cardiac output (l/min) is lower in CMS when compared with sea-level (SL) dwellers. Mean pulmonary acceleration time (ms) is significantly lower in CMS subjects than in SL and HA natives, and pulmonary vascular resistance index (Wood units) is higher in CMS and HA natives when compared with SL dwellers. Systemic blood pressure has similar values in CMS patients and healthy HA natives, but some differences arise in its control mechanisms. Although CMS individuals have a less effective vasoconstrictor reflex, their tolerance to orthostatic stress is similar to that of healthy HA natives which might be explained in terms of the larger blood volume present in CMS subjects. At present research is directed to design strategies on pharmacological intervention for CMS treatment. Recently, a clinical trial with acetazolamide, in patients with CMS has proven to be effective in increasing mean pulmonary acceleration time and decreasing pulmonary vascular resistance index, which might be indirectly due the reduction of hematocrit.
Collapse
|
30
|
Launay T, Hagström L, Lottin-Divoux S, Marchant D, Quidu P, Favret F, Duvallet A, Darribère T, Richalet JP, Beaudry M. Blunting effect of hypoxia on the proliferation and differentiation of human primary and rat L6 myoblasts is not counteracted by Epo. Cell Prolif 2010; 43:1-8. [PMID: 20070732 DOI: 10.1111/j.1365-2184.2009.00648.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
OBJECTIVES The aim of this study was to evaluate whether hypoxia and/or erythropoietin would be able to modulate proliferation/differentiation processes of rat and human myoblasts. MATERIALS AND METHODS Rat L6 and primary human myoblasts were grown in 21% or 1% O(2) in the presence or absence of recombinant human erythropoietin (RhEpo). Presence of erythropoietin receptors (EpoR) was assayed using RT-PCR and Western blotting techniques. Cell proliferation was evaluated by determining the doubling time and kinetics of cultures by counting cells. Cell differentiation was analysed by determining myogenic fusion index using antibodies against the myosin heavy chain. Expression of myogenin and myosin heavy chain (MHC) proteins were evaluated using the Western blotting technique. RESULTS After 96 h culture in growth medium for 2.5 and 9 h, doubling time of L6 and human primary myoblasts respectively, had increased in 1% O(2) conditions (P < 0.01). Kinetics of culture showed alteration in proliferation at 72 h in L6 myoblast cultures and at 4 days in human primary myoblasts. The myogenic fusion index had reduced by 30% in L6 myoblasts and by 20% in human myoblasts (P < 0.01). Expression of myogenin and MHC had reduced by around 50%. Despite presence of EpoR mRNA and protein, RhEpo did not counteract the effects of hypoxia either in L6 cells or in human myoblasts. CONCLUSIONS The data show that exposure to hypoxic conditions (1% O(2)) of rat and human myoblasts altered their proliferation and differentiation processes. They also show that Epo is not an efficient growth factor to counteract this deleterious effect.
Collapse
Affiliation(s)
- T Launay
- Laboratoire Réponses cellulaires et fonctionnelles à l'hypoxie, Université Paris 13, Bobigny, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Weidemann A, Kerdiles YM, Knaup KX, Rafie CA, Boutin AT, Stockmann C, Takeda N, Scadeng M, Shih AY, Haase VH, Simon MC, Kleinfeld D, Johnson RS. The glial cell response is an essential component of hypoxia-induced erythropoiesis in mice. J Clin Invest 2009; 119:3373-83. [PMID: 19809162 DOI: 10.1172/jci39378] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2009] [Accepted: 08/05/2009] [Indexed: 11/17/2022] Open
Abstract
A key adaptation to environmental hypoxia is an increase in erythropoiesis, driven by the hormone erythropoietin (EPO) through what is traditionally thought to be primarily a renal response. However, both neurons and astrocytes (the largest subpopulation of glial cells in the CNS) also express EPO following ischemic injury, and this response is known to ameliorate damage to the brain. To investigate the role of glial cells as a component of the systemic response to hypoxia, we created astrocyte-specific deletions of the murine genes encoding the hypoxia-inducible transcription factors HIF-1alpha and HIF-2alpha and their negative regulator von Hippel-Lindau (VHL) as well as astrocyte-specific deletion of the HIF target gene Vegf. We found that loss of the hypoxic response in astrocytes does not cause anemia in mice but is necessary for approximately 50% of the acute erythropoietic response to hypoxic stress. In accord with this, erythroid progenitor cells and reticulocytes were substantially reduced in number in mice lacking HIF function in astrocytes following hypoxic stress. Thus, we have demonstrated that the glial component of the CNS is an essential component of hypoxia-induced erythropoiesis.
Collapse
Affiliation(s)
- Alexander Weidemann
- Division of Biology, University of California, San Diego, La Jolla, California 92093, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
Ribatti D, Crivellato E, Nico B, Guidolin D, Gassmann M, Djonov V. Mast cells and macrophages in duodenal mucosa of mice overexpressing erythropoietin. J Anat 2009; 215:548-54. [PMID: 19691658 DOI: 10.1111/j.1469-7580.2009.01131.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
There is increasing evidence suggesting a wider biological role of erythropoietin (Epo) and Epo receptor (EpoR) not related to erythropoiesis, such as the detection of EpoR in other cells, i.e. polymorphonuclear leukocytes, megakaryocytes, endothelial, myocardial and neural cells. In this study, by using a mouse model (designated tg6) that constitutively overexpresses human Epo in an oxygen-independent manner, we have investigated mast cell and macrophage number and distribution in duodenal mucosa using immunohistochemical, morphometric and image analysis methods. The results showed that tryptase-positive mast cells and BM8-positive macrophages were more numerous in duodenal mucosa specimens of tg6 mice compared with wild-type mice. Moreover, whereas in wild-type specimens both mast cells and macrophages were generally scattered throughout the villus, in tg6 specimens they were aligned along the axis of the villus. Morphometric analysis confirms this observation, and the quantitative analysis of the spatial distribution of the cells in duodenal villi indicated that in both wild-type and tg6 groups the macrophage and mast cell distribution was characterized by significant deviations from randomness. In addition, an increased number of c-kit-positive cells have been identified in the villus axis of tg6 mice, indicating an expanded compartment of mast cell precursors in the intestinal mucosa of these animals. Finally, we have also demonstrated that in tg6 specimens the number of duodenal epithelial cells positive for Epo were significantly higher as compared to wild type. Overall, these data confirm that Epo, acting as a general stimulator of the hemopoietic compartment, is able to induce an expansion of two effectors of the immune response, mast cells and macrophages, in a specific peripheral site, the duodenal mucosa, in the tg6 mouse experimental model.
Collapse
Affiliation(s)
- Domenico Ribatti
- Department of Human Anatomy and Histology, University of Bari Medical School, Bari, Italy.
| | | | | | | | | | | |
Collapse
|
33
|
Schuler B, Rettich A, Vogel J, Gassmann M, Arras M. Optimized surgical techniques and postoperative care improve survival rates and permit accurate telemetric recording in exercising mice. BMC Vet Res 2009; 5:28. [PMID: 19646283 PMCID: PMC2727500 DOI: 10.1186/1746-6148-5-28] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2009] [Accepted: 08/02/2009] [Indexed: 11/17/2022] Open
Abstract
Background The laboratory mouse is commonly used as a sophisticated model in biomedical research. However, experiments requiring major surgery frequently lead to serious postoperative complications and death, particularly if genetically modified mice with anatomical and physiological abnormalities undergo extensive interventions such as transmitter implantation. Telemetric transmitters are used to study cardiovascular physiology and diseases. Telemetry yields reliable and accurate measurement of blood pressure in the free-roaming, unanaesthetized and unstressed mouse, but data recording is hampered substantially if measurements are made in an exercising mouse. Thus, we aimed to optimize transmitter implantation to improve telemetric signal recording in exercising mice as well as to establish a postoperative care regimen that promotes convalescence and survival of mice after major surgery in general. Results We report an optimized telemetric transmitter implantation technique (fixation of the transmitter body on the back of the mouse with stainless steel wires) for subsequent measurement of arterial blood pressure during maximal exercise on a treadmill. This technique was used on normal (wildtype) mice and on transgenic mice with anatomical and physiological abnormalities due to constitutive overexpression of recombinant human erythropoietin. To promote convalescence of the animals after surgery, we established a regimen for postoperative intensive care: pain treatment (flunixine 5 mg/kg bodyweight, subcutaneously, twice per day) and fluid therapy (600 μl, subcutaneously, twice per day) were administrated for 7 days. In addition, warmth and free access to high energy liquid in a drinking bottle were provided for 14 days following transmitter implantation. This regimen led to a substantial decrease in overall morbidity and mortality. The refined postoperative care and surgical technique were particularly successful in genetically modified mice with severely compromised physiological capacities. Conclusion Recovery and survival rates of mice after major surgery were significantly improved by careful management of postoperative intensive care regimens including key supportive measures such as pain relief, administration of fluids, and warmth. Furthermore, fixation of the blood pressure transmitter provided constant reliable telemetric recordings in exercising mice.
Collapse
Affiliation(s)
- Beat Schuler
- University of Zurich, Vetsuisse Faculty, Institute of Veterinary Physiology, and Zurich Center for Integrative Human Physiology, 8057 Zurich, Switzerland.
| | | | | | | | | |
Collapse
|
34
|
Soliz J, Thomsen JJ, Soulage C, Lundby C, Gassmann M. Sex-dependent regulation of hypoxic ventilation in mice and humans is mediated by erythropoietin. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1837-46. [PMID: 19321698 DOI: 10.1152/ajpregu.90967.2008] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Acclimatization to hypoxic exposure relies on an elevated ventilation and erythropoietic activity. We recently proposed that erythropoietin (Epo) links both responses: apart from red blood cell production, cerebral and plasma Epo interact with the central and peripheral respiratory centers. Knowing that women cope better than men with reduced oxygen supply (as observed at high altitude), we analyzed the hypoxic ventilatory response in Epo-overexpressing transgenic male and female mice with high Epo levels in brain and plasma (Tg6) or in wild-type animals injected with recombinant human Epo (rhEpo). Exposure to moderate and severe hypoxia as well as to hyperoxia and injection of domperidone, a potent peripheral ventilatory stimulant, revealed that the presence of transgenic or rhEpo extensively increased the hypoxic ventilatory response in female mice compared with their corresponding male siblings. Alterations of catecholamines in the brain stem's respiratory centers were also sex dependent. In a proof-of-concept study, human volunteers were intravenously injected with 5,000 units rhEpo and subsequently exposed to 10% oxygen. Compared with men, the hypoxic ventilatory response was significantly increased in women. We conclude that Epo exerts a sex-dependent impact on hypoxic ventilation improving the response in female mice and in women that most probably involves sexual hormones. Our data provides an explanation as to why women are less susceptible to hypoxia-associated syndromes than men.
Collapse
Affiliation(s)
- Jorge Soliz
- nstitute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology, University of Zurich, Zurich CH-8057, Switzerland
| | | | | | | | | |
Collapse
|
35
|
Zebrafish mutants in the von Hippel-Lindau tumor suppressor display a hypoxic response and recapitulate key aspects of Chuvash polycythemia. Blood 2009; 113:6449-60. [PMID: 19304954 DOI: 10.1182/blood-2008-07-167890] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have generated 2 zebrafish lines carrying inactivating germline mutations in the von Hippel-Lindau (VHL) tumor suppressor gene ortholog vhl. Mutant embryos display a general systemic hypoxic response, including the up-regulation of hypoxia-induced genes by 1 day after fertilization and a severe hyperventilation and cardiophysiologic response. The vhl mutants develop polycythemia with concomitantly increased epo/epor mRNA levels and erythropoietin signaling. In situ hybridizations reveal global up-regulation of both red and white hematopoietic lineages. Hematopoietic tissues are highly proliferative, with enlarged populations of c-myb(+) hematopoietic stem cells and circulating erythroid precursors. Chemical activation of hypoxia-inducible factor signaling recapitulated aspects of the vhl(-/-) phenotype. Furthermore, microarray expression analysis confirms the hypoxic response and hematopoietic phenotype observed in vhl(-/-) embryos. We conclude that VHL participates in regulating hematopoiesis and erythroid differentiation. Injections with human VHLp30 and R200W mutant mRNA demonstrate functional conservation of VHL between mammals and zebrafish at the amino acid level, indicating that vhl mutants are a powerful new tool to study genotype-phenotype correlations in human disease. Zebrafish vhl mutants are the first congenital embryonic viable systemic vertebrate animal model for VHL, representing the most accurate model for VHL-associated polycythemia to date. They will contribute to our understanding of hypoxic signaling, hematopoiesis, and VHL-associated disease progression.
Collapse
|
36
|
Ruvinov E, Sharabani-Yosef O, Nagler A, Einbinder T, Feinberg MS, Holbova R, Douvdevani A, Leor J. Transplantation of genetically engineered cardiac fibroblasts producing recombinant human erythropoietin to repair the infarcted myocardium. FIBROGENESIS & TISSUE REPAIR 2008; 1:7. [PMID: 19014419 PMCID: PMC2585557 DOI: 10.1186/1755-1536-1-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2008] [Accepted: 11/03/2008] [Indexed: 11/29/2022]
Abstract
Background Erythropoietin possesses cellular protection properties. The aim of the present study was to test the hypothesis that in situ expression of recombinant human erythropoietin (rhEPO) would improve tissue repair in rat after myocardial infarction (MI). Methods and results RhEPO-producing cardiac fibroblasts were generated ex vivo by transduction with retroviral vector. The anti-apoptotic effect of rhEPO-producing fibroblasts was evaluated by co-culture with rat neonatal cardiomyocytes exposed to H2O2-induced oxidative stress. Annexin V/PI assay and DAPI staining showed that compared with control, rhEPO forced expression markedly attenuated apoptosis and improved survival of cultured cardiomyocytes. To test the effect of rhEPO on the infarcted myocardium, Sprague-Dawley rats were subjected to permanent coronary artery occlusion, and rhEPO-producing fibroblasts, non-transduced fibroblasts, or saline, were injected into the scar tissue seven days after infarction. One month later, immunostaining identified rhEPO expression in the implanted engineered cells but not in controls. Compared with non-transduced fibroblasts or saline injection, implanted rhEPO-producing fibroblasts promoted vascularization in the scar, and prevented cell apoptosis. By two-dimensional echocardiography and postmortem morphometry, transplanted EPO-engineered fibroblasts did not prevent left ventricular (LV) dysfunction and adverse LV remodeling 5 and 9 weeks after MI. Conclusion In situ expression of rhEPO enhances vascularization and reduces cell apoptosis in the infarcted myocardium. However, local EPO therapy is insufficient for functional improvement after MI in rat.
Collapse
Affiliation(s)
- Emil Ruvinov
- Neufeld Cardiac Research Institute, Sheba Medical Center, Tel-Aviv University, Tel-Hashomer, Israel
| | | | | | | | | | | | | | | |
Collapse
|
37
|
Erythropoiesis-stimulating agents and other methods to enhance oxygen transport. Br J Pharmacol 2008; 154:529-41. [PMID: 18362898 DOI: 10.1038/bjp.2008.89] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Oxygen is essential for life, and the body has developed an exquisite method to collect oxygen in the lungs and transport it to the tissues. Hb contained within red blood cells (RBCs), is the key oxygen-carrying component in blood, and levels of RBCs are tightly controlled according to demand for oxygen. The availability of oxygen plays a critical role in athletic performance, and agents that enhance oxygen delivery to tissues increase aerobic power. Early methods to increase oxygen delivery included training at altitude, and later, transfusion of packed RBCs. A breakthrough in understanding how RBC formation is controlled included the discovery of erythropoietin (Epo) and cloning of the EPO gene. Cloning of the EPO gene was followed by commercial development of recombinant human Epo (rHuEpo). Legitimate use of this and other agents that affect oxygen delivery is important in the treatment of anaemia (low Hb levels) in patients with chronic kidney disease or in cancer patients with chemotherapy-induced anaemia. However, competitive sports was affected by illicit use of rHuEpo to enhance performance. Testing methods for these agents resulted in a cat-and-mouse game, with testing labs attempting to detect the use of a drug or blood product to improve athletic performance (doping) and certain athletes developing methods to use the agents without being detected. This article examines the current methods to enhance aerobic performance and the methods to detect illicit use.
Collapse
|
38
|
Oxygen supply and retinal function: insights from a transgenic animal model. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008. [PMID: 18188942 DOI: 10.1007/978-0-387-74904-4_19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
|
39
|
Gassmann M, Manini A, Stallmach T, Saam B, Kuhn G, Grenacher B, Bogdanova AY, Vogel J. Abortion in mice with excessive erythrocytosis is due to impaired arteriogenesis of the uterine arcade. Biol Reprod 2008; 78:1049-57. [PMID: 18256329 DOI: 10.1095/biolreprod.107.065532] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
We postulate that repeated pregnancy loss, intrauterine growth restriction, and preeclampsia are caused by impaired elevation of uterine blood flow due to disturbed arteriogenesis of the uterine arcade. This hypothesis is based on the observation that pregnant human erythropoietin-overexpressing (plasma levels elevated 12-fold) mice (termed tg6 mice) suffering from excessive erythrocytosis generally abort at midgestation unless their hematocrit of 0.85 is drastically lowered. Transgenic mice show placental malformations that parallel those observed in pregnant women suffering from impaired uterine perfusion. Shear stress, a key factor inducing arteriogenesis, was 5-fold lower in tg6 mice compared with wildtype (WT) littermates. Consequently, uterine artery growth was reduced, and dramatically fewer viable pups (1.63 +/- 2.20 vs. 8.10 +/- 0.74 in WT) of lower weight (1.29 +/- 0.07 g vs. 1.62 +/- 0.12 g in WT) were delivered in first pregnancies. Only in subsequent pregnancies did tg6 deliver approximately the expected number of pups. Birth weights of tg6 offspring, however, remained reduced. As the spleen is a major site of extramedullary erythropoiesis in tg6 animals, splenectomy reduced the hematocrit to 0.6-0.7. In turn, shear stress increased to normal values, and splenectomized primiparous tg6 showed normal uterine artery growth and delivery of pups similar in number and weight compared with WT. We conclude that poor arteriogenesis is a previously unappreciated cause for clinically important pregnancy complications.
Collapse
Affiliation(s)
- Max Gassmann
- Institute of Veterinary Physiology, Vetsuisse Faculty, University of Zürich, CH-8057 Zürich, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Abstract
An additional target for reducing infarct size, namely, attenuation of apoptosis, has recently emerged. Erythropoietin (Epo) exhibits properties that may attenuate this process and enhance neovascularization, thereby preserving jeopardized myocardium. Potentially adverse effects of Epo, including hypertension, thrombosis and possible exacerbation of occult neoplasms can likely be averted with analogues such as carbamylated and asialo Epo, which are devoid of erythropoietic effects, yet retain tissue-protective characteristics. With a single, but adequate dose of Epo administered early after the onset of acute myocardial infarction, coupled with therapy to induce reperfusion, tissue protection conferred by Epo and its analogues may facilitate the preservation of myocardium subjected to ischemic insults, thereby improving prognosis.
Collapse
Affiliation(s)
- K Nayan S Rao
- Rashid Hospital, Department of Cardiology, and, Department of Health and Medical Services, Dubai, United Arab Emirates
| | - Azan S Binbrek
- Rashid Hospital, Department of Cardiology, Dubai, United Arab Emirates
| | - Burton E Sobel
- University of Vermont, Cardiovascular Research Institute, Burlington, VT, USA
| |
Collapse
|
41
|
Soliz J, Soulage C, Hermann DM, Gassmann M. Acute and chronic exposure to hypoxia alters ventilatory pattern but not minute ventilation of mice overexpressing erythropoietin. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1702-10. [PMID: 17652365 DOI: 10.1152/ajpregu.00350.2007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Apart from enhancing red blood cell production, erythropoietin (Epo) has been shown to modulate the ventilatory response to reduced oxygen supply. Both functions are crucial for the organism to cope with increased oxygen demand. In the present work, we analyzed the impact of Epo and the resulting excessive erythrocytosis in the neural control of normoxic and hypoxic ventilation. To this end, we used our transgenic mouse line (Tg6) that shows high levels of human Epo in brain and plasma, the latter leading to a hematocrit of ∼80%. Interestingly, while normoxic and hypoxic ventilation in Tg6 mice was similar to WT mice, Tg6 mice showed an increased respiratory frequency but a decreased tidal volume. Knowing that Epo modulates catecholaminergic activity, the altered catecholaminergic metabolism measured in brain stem suggested that the increased respiratory frequency in Tg6 mice was related to the overexpression of Epo in brain. In the periphery, higher response to hyperoxia (Dejours test), as well as reduced tyrosine hydroxylase activity in carotid bodies, revealed a higher chemosensitivity to oxygen in transgenic mice. Moreover, in line with the decreased activity of the rate-limiting enzyme for dopamine synthesis, the intraperitoneal injection of a highly specific peripheral ventilatory stimulant, domperidone, did not stimulate hypoxic ventilatory response in Tg6 mice. These results suggest that high Epo plasma levels modulate the carotid body's chemotransduction. All together, these findings are relevant for understanding the cross-talk between the ventilatory and erythropoietic systems exposed to hypoxia.
Collapse
Affiliation(s)
- Jorge Soliz
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland
| | | | | | | |
Collapse
|
42
|
Villafuerte FC, Cárdenas-Alayza R, Macarlupú JL, Monge-C C, León-Velarde F. Ventilatory response to acute hypoxia in transgenic mice over-expressing erythropoietin: Effect of acclimation to 3-week hypobaric hypoxia. Respir Physiol Neurobiol 2007; 158:243-50. [PMID: 17693141 DOI: 10.1016/j.resp.2007.06.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2006] [Revised: 06/15/2007] [Accepted: 06/15/2007] [Indexed: 11/23/2022]
Abstract
We used transgenic mice constitutively over-expressing erythropoietin ("tg6" mice) and wild-type (wt) mice to investigate whether the high hematocrit (hct), consequence of Epo over-expression affected: (1) the normoxic ventilation (V (E)) and the acute hypoxic ventilatory response (HVR) and decline (HVD), (2) the increase in ventilation observed after chronic exposure to hypobaric hypoxia (430mmHg for 21 days), (3) the respiratory "blunting", and (4) the erythrocythemic response induced by chronic hypoxia exposure. V (E) was found to be similar in tg6 and wt mice in normoxia (FIO2=0.21). Post-acclimation V (E) was significantly elevated in every time point in wt mice at FIO2=0.10 when compared to pre-acclimation values. In contrast, tg6 mice exhibited a non-significant increase in V (E) throughout acute hypoxia exposure. Changes in V (E) are associated with adjustments in tidal volume (V(T)). HVR and HVD were independent of EE in tg6 and wt mice before chornic hypoxia exposure. HVR was significantly greater in wt than in tg6 mice after chronic hypoxia. After acclimation, HVD decreased in tg6 mice. Chronic hypoxia exposure caused hct to increase significantly in wt mice, while only a marginal increase occurred in the tg6 group. Although pre-existent EE does not appear to have an effect on HVR, the observation of alterations on V(T) suggests that it may contribute to time-dependent changes in ventilation and in the acute HVR during exposure to chronic hypoxia. In addition, our results suggest that EE may lead to an early "blunting" of the ventilatory response.
Collapse
Affiliation(s)
- Francisco C Villafuerte
- Laboratorio de Transporte de Oxígeno, Departamento de Ciencias Biológicas y Fisiológicas, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru.
| | | | | | | | | |
Collapse
|
43
|
Paffett-Lugassy N, Hsia N, Fraenkel PG, Paw B, Leshinsky I, Barut B, Bahary N, Caro J, Handin R, Zon LI. Functional conservation of erythropoietin signaling in zebrafish. Blood 2007; 110:2718-26. [PMID: 17579187 PMCID: PMC1988930 DOI: 10.1182/blood-2006-04-016535] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Erythropoietin (Epo) and its cognate receptor (EpoR) are required for maintaining adequate levels of circulating erythrocytes during embryogenesis and adulthood. Here, we report the functional characterization of the zebrafish epo and epor genes. The expression of epo and epor was evaluated by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) and whole-mount in situ hybridization, revealing marked parallels between zebrafish and mammalian gene expression patterns. Examination of the hypochromic mutant, weissherbst, and adult hypoxia-treated hearts indicate that zebrafish epo expression is induced by anemia and hypoxia. Overexpression of epo mRNA resulted in severe polycythemia, characterized by a striking increase in the number of cells expressing scl, c-myb, gata1, ikaros, epor, and betae1-globin, suggesting that both the erythroid progenitor and mature erythrocyte compartments respond to epo. Morpholino-mediated knockdown of the epor caused a slight decrease in primitive and complete block of definitive erythropoiesis. Abrogation of STAT5 blocked the erythropoietic expansion by epo mRNA, consistent with a requirement for STAT5 in epo signaling. Together, the characterization of zebrafish epo and epor demonstrates the conservation of an ancient program that ensures proper red blood cell numbers during normal homeostasis and under hypoxic conditions.
Collapse
Affiliation(s)
- Noëlle Paffett-Lugassy
- Stem Cell Program and Division of Hematology/Oncology, Children's Hospital and Dana-Farber Cancer Institute, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Föller M, Kasinathan RS, Koka S, Huber SM, Schuler B, Vogel J, Gassmann M, Lang F. Enhanced susceptibility to suicidal death of erythrocytes from transgenic mice overexpressing erythropoietin. Am J Physiol Regul Integr Comp Physiol 2007; 293:R1127-34. [PMID: 17567717 DOI: 10.1152/ajpregu.00110.2007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Eryptosis, a suicidal death of mature erythrocytes, is characterized by decrease of cell volume, cell membrane blebbing, and breakdown of cell membrane asymmetry with phosphatidylserine exposure at the cell surface. Triggers of eryptosis include increased cytosolic Ca(2+) activity, which could result from activation of Ca(2+)-permeable cation channels. Ca(2+) triggers phosphatidylserine exposure and activates Ca(2+)-sensitive K(+) channels, leading to cellular K(+) loss and cell shrinkage. The cation channels and thus eryptosis are stimulated by Cl(-) removal and inhibited by erythropoietin. The present experiments explored eryptosis in transgenic mice overexpressing erythropoietin (tg6). Erythrocytes were drawn from tg6 mice and their wild-type littermates (WT). Phosphatidylserine exposure was estimated from annexin binding and cell volume from forward scatter in fluorescence-activated cell sorting (FACS) analysis. The percentage of annexin binding was significantly larger and forward scatter significantly smaller in tg6 than in WT erythrocytes. Transgenic erythrocytes were significantly more resistant to osmotic lysis than WT erythrocytes. Cl(-) removal and exposure to the Ca(2+) ionophore ionomycin (1 microM) increased annexin binding and decreased forward scatter, effects larger in tg6 than in WT erythrocytes. The K(+) ionophore valinomycin (10 nM) triggered eryptosis in both tg6 and WT erythrocytes and abrogated differences between genotypes. An increase of extracellular K(+) concentration to 125 mM blunted the difference between tg6 and WT erythrocytes. Fluo-3 fluorescence reflecting cytosolic Ca(2+) activity was larger in tg6 than in WT erythrocytes. In conclusion, circulating erythrocytes from tg6 mice are sensitized to triggers of eryptosis but more resistant to osmotic lysis, properties at least partially due to enhanced Ca(2+) entry and increased K(+) channel activity.
Collapse
Affiliation(s)
- Michael Föller
- Physiologisches Institut, der Universität Tübingen, Gmelinstrasse 5, D 72076 Tübingen, Germany
| | | | | | | | | | | | | | | |
Collapse
|
45
|
Stritzke J, Mayer B, Lieb W, Luchner A, Döring A, Hense HW, Schunkert H. Haematocrit levels and left ventricular geometry: results of the MONICA Augsburg Echocardiographic Substudy. J Hypertens 2007; 25:1301-9. [PMID: 17563545 DOI: 10.1097/hjh.0b013e3280f9df97] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Extreme alterations in blood count such as anaemia or polycythemia are known to cause circulatory changes and, if these alterations persist, adaptations of cardiac geometry. OBJECTIVES To investigate further the association between haematocrit levels and left ventricular geometry in a population-based sample. METHODS We examined 687 women and 648 men, aged 25-74 years, participating in the third population-based MONICA Augsburg study. Anthropometry, blood pressure, laboratory measurements and M-mode echocardiography were obtained using standardized methods. RESULTS Haematocrit levels were inversely related to end-diastolic diameters (P < 0.001). By contrast, septal and posterior wall thickness displayed parabolic association curves with nadirs at physiological haematocrit levels (P < 0.001). These associations remained significant after adjustment for age, sex, body fat, hypertension, diabetes mellitus, cardiovascular disease, heart failure, serum creatinine, and were likewise found for haemoglobin levels or numbers of erythrocytes. These correlations appeared to be secondary to changes in blood pressure and stroke volume that correlated either positively (blood pressure) or inversely (stroke volume) with haematocrit levels. Consequently, a concentric pattern of left ventricular hypertrophy, i.e. a relative wall thickness of 0.45 or greater, was significantly more prevalent in subjects with high haematocrit levels than in those with intermediate haematocrit levels. By contrast, an eccentric left ventricular hypertrophy, i.e. relative wall thickness less than 0.45, was more common in subjects with low haematocrit levels. CONCLUSION In the general population, the variability of haematocrit levels and its haemodynamic consequences translates to distinct patterns of left ventricular geometry.
Collapse
Affiliation(s)
- Jan Stritzke
- Medizinische Klinik II, Universitätsklinikum Schleswig-Holstein, Campus Lübeck, Lübeck, Germany
| | | | | | | | | | | | | |
Collapse
|
46
|
Constitutively overexpressed erythropoietin reduces infarct size in a mouse model of permanent coronary artery ligation. Methods Enzymol 2007; 435:147-55. [PMID: 17998053 DOI: 10.1016/s0076-6879(07)35008-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In view of the emerging role of recombinant human erythropoietin (rhEPO) as a novel therapeutical approach in myocardial ischemia, we performed the first two-way parallel comparison to test the effects of rhEPO pretreatment (1000 U/kg, 12h before surgery) versus EPO transgenic overexpression in a mouse model of myocardial infarction. Unlike EPO transgenic mice who doubled their hematocrit, rhEPO pretreated mice maintained an unaltered hematocrit, thereby offering the possibility to discern erythropoietic-dependent from erythropoietic-independent protective effects of EPO. Animals pretreated with rhEPO as well as EPO transgenic mice underwent permanent left anterior descending (LAD) coronary artery ligation. Resulting infarct size was determined 24h after LAD ligation by hematoxylin/eosin staining, and morphometrical analysis was performed by computerized planimetry. A large reduction in infarction size was observed in rhEPO-treated mice (-74% +/- 14.51; P = 0.0002) and an even more pronounced reduction in the EPO transgenic group (-87% +/- 6.31; P < 0.0001) when compared to wild-type controls. Moreover, while searching for novel early ischemic markers, we analyzed expression of hypoxia-sensitive Wilms' tumor suppressor gene (WT1) in infarcted hearts. We found that its expression correlated with the infarct area, thereby providing the first demonstration that WT1 is a useful early marker of myocardial infarction. This study demonstrates for the first time that, despite high hematocrit levels, endogenously overexpressed EPO provides protection against myocardial infarction in a murine model of permanent LAD ligation.
Collapse
|
47
|
Duarte R, Niero R, Doretto J, Manzan R, Kogika M. Eritrocitose associada a tumor venéreo transmissível em cão: relato de caso. ARQ BRAS MED VET ZOO 2006. [DOI: 10.1590/s0102-09352006000600007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Descreve-se um caso de eritrocitose absoluta (hematócrito: 74%, hemoglobina: 24,2g/dl) em um cão com tumor venéreo transmissível cutâneo. A concentração de hemoglobina e o hematócrito retornaram ao valor normal após o tratamento com vincristina. A remissão da eritrocitose após o tratamento é sugestiva de uma associação entre o tumor e a alteração hematológica.
Collapse
|
48
|
Fantacci M, Bianciardi P, Caretti A, Coleman TR, Cerami A, Brines M, Samaja M. Carbamylated erythropoietin ameliorates the metabolic stress induced in vivo by severe chronic hypoxia. Proc Natl Acad Sci U S A 2006; 103:17531-6. [PMID: 17090665 PMCID: PMC1859963 DOI: 10.1073/pnas.0608814103] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2006] [Indexed: 12/22/2022] Open
Abstract
Ischemia and chronic hypoxia (CH) trigger a variety of adverse effects arising from metabolic stress that injures cells. In response to reduced O2, hypoxia-inducible factor 1alpha (HIF-1alpha) activates erythropoietin (Epo) as well as many other target genes that counteract the effects of O2 deficiency. Epo produced by the kidney stimulates erythrocyte production, leading to decreased HIF-1alpha production by improved tissue O2 delivery. However, Epo is produced by many other tissues, and it is currently unclear to what extent, if any, locally produced Epo modulates HIF-1alpha expression. Derivatives of Epo that possess tissue-protective activities but do not stimulate erythropoiesis [e.g., carbamylated Epo (CEpo)] are useful tools with which to determine whether exogenous Epo modulates HIF-1alpha in the absence of changes in hemoglobin concentration. We compared the effects of CH (6.5% O2 for 10 days) with or without CEpo administered by daily s.c. injection (10 microg/kg of body weight). CEpo administration did not alter the survival rate, weight loss, or increased hemoglobin concentration associated with CH. Therefore, CEpo does not directly suppress HIF-mediated erythropoiesis. CEpo does, however, prevent CH-induced neuronal increases of HIF-1alpha and Epo receptor-associated immunoreactivity (a measure of stress) while reducing the apoptotic index. In contrast, the myocardium did not exhibit increased HIF-1alpha expression during CH, although CEpo did reduce the apoptotic index. These observations therefore demonstrate that CEpo administration reduces the metabolic stress caused by severe CH, resulting in improved cellular survival independent of erythrocyte production.
Collapse
Affiliation(s)
- Monica Fantacci
- *Department of Medicine, Surgery, and Dentistry, University of Milan, San Paolo Hospital, Milan 20142, Italy; and
| | - Paola Bianciardi
- *Department of Medicine, Surgery, and Dentistry, University of Milan, San Paolo Hospital, Milan 20142, Italy; and
| | - Anna Caretti
- *Department of Medicine, Surgery, and Dentistry, University of Milan, San Paolo Hospital, Milan 20142, Italy; and
| | - Thomas R. Coleman
- The Kenneth S. Warren Institute and Warren Pharmaceuticals, Ossining, NY 10562
| | - Anthony Cerami
- The Kenneth S. Warren Institute and Warren Pharmaceuticals, Ossining, NY 10562
| | - Michael Brines
- The Kenneth S. Warren Institute and Warren Pharmaceuticals, Ossining, NY 10562
| | - Michele Samaja
- *Department of Medicine, Surgery, and Dentistry, University of Milan, San Paolo Hospital, Milan 20142, Italy; and
| |
Collapse
|
49
|
Heinicke K, Baum O, Ogunshola OO, Vogel J, Stallmach T, Wolfer DP, Keller S, Weber K, Wagner PD, Gassmann M, Djonov V. Excessive erythrocytosis in adult mice overexpressing erythropoietin leads to hepatic, renal, neuronal, and muscular degeneration. Am J Physiol Regul Integr Comp Physiol 2006; 291:R947-56. [PMID: 16690772 DOI: 10.1152/ajpregu.00152.2006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To investigate the consequences of inborn excessive erythrocytosis, we made use of our transgenic mouse line (tg6) that constitutively overexpresses erythropoietin (Epo) in a hypoxia-independent manner, thereby reaching hematocrit levels of up to 0.89. We detected expression of human Epo in the brain and, to a lesser extent, in the lung but not in the heart, kidney, or liver of tg6 mice. Although no acute cardiovascular complications are observed, tg6 animals have a reduced lifespan. Decreased swim performance was observed in 5-mo-old tg6 mice. At about 7 mo, several tg6 animals developed spastic contractions of the hindlimbs followed by paralysis. Morphological analysis by light and electron microscopy showed degenerative processes in liver and kidney characterized by increased vascular permeability, chronic progressive inflammation, hemosiderin deposition, and general vasodilatation. Moreover, most of the animals showed severe nerve fiber degeneration of the sciatic nerve, decreased number of neuromuscular junctions, and degeneration of skeletal muscle fibers. Most probably, the developing demyelinating neuropathy resulted in muscular degeneration demonstrated in the extensor digitorum longus muscle. Taken together, chronically increased Epo levels inducing excessive erythrocytosis leads to multiple organ degeneration and reduced life expectancy. This model allows investigation of the impact of excessive erythrocytosis in individuals suffering from polycythemia vera, chronic mountain sickness, or in subjects tempted to abuse Epo by means of gene doping.
Collapse
Affiliation(s)
- Katja Heinicke
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurich Center for Integrative Human Physiology (ZIHP), Switzerland
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Ogunshola OO, Djonov V, Staudt R, Vogel J, Gassmann M. Chronic excessive erythrocytosis induces endothelial activation and damage in mouse brain. Am J Physiol Regul Integr Comp Physiol 2006; 290:R678-84. [PMID: 16254128 DOI: 10.1152/ajpregu.00246.2005] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Excessive erythrocytosis results in severely increased blood viscosity, which may have significant detrimental effects on endothelial cells and, ultimately, function of the vascular endothelium. Because blood-brain barrier stability is crucial for normal physiological function, we used our previously characterized erythropoietin-overexpressing transgenic (tg6) mouse line (which has a hematocrit of 0.8–0.9) to investigate the effect of excessive erythrocytosis on vessel number, structure, and integrity in vivo. These mice have abnormally high levels of nitric oxide (NO), a potent proinflammatory molecule, suggesting altered vascular permeability and function. In this study, we observed that brain vessel density of tg6 mice was significantly reduced (16%) and vessel diameter was significantly increased (15%) compared with wild-type mice. Although no significant increases in vascular permeability under normoxic or acute hypoxic conditions (8% O2for 4 h) were detected, electron-microscopic analysis revealed altered morphological characteristics of the tg6 endothelium. Tg6 brain vascular endothelial cells appeared to be activated, with increased luminal protrusions reminiscent of ongoing inflammatory processes. Consistent with this observation, we detected increased levels of intercellular adhesion molecule-1 and von Willebrand factor, markers of endothelial activation and damage, in brain tissue. We propose that chronic excessive erythrocytosis and sustained high hematocrit cause endothelial damage, which may, ultimately, increase susceptibility to vascular disease.
Collapse
Affiliation(s)
- O O Ogunshola
- Institute of Veterinary Physiology, Vetsuisse Faculty and Zurixh Centre for Integrative Human Physiology, University of Zürich, Winterthurerstrasse 260, CH-8057 Zurich, Switzerland.
| | | | | | | | | |
Collapse
|