Cooley's Anemia 9th Symposium

Web sites

Berloni Foundation for the Control of Thalassemia
Located in Pesaro, Italy, the foundation provides support for research on bone marrow transplantation for curing beta thalassemia.

Centers for Disease Control and Prevention (CDC)
The CDC is developing programs focused on Cooley's anemia and other thalassemias.

Cooley's Anemia Foundation
The Cooley's Anemia Foundation is dedicated to serving people afflicted with various forms of thalassemia, most notably the major form of this genetic blood disease, Cooley's anemia/thalassemia major.

National Heart, Lung and Blood Institute
An agency of the National Institutes of Health, the NHLBI provides leadership and research funding for diseases of the heart, blood vessels, lung, and blood.

The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
NIDDK conducts and supports basic and clinical research on many of the most serious diseases affecting public health.

Northern California Comprehensive Thalassemia Center
Located at Children's Hospital Oakland, the center provides education, genetic counseling, and psychosocial care to affected families and those at risk for carrying the disease.

The Thalassemia Foundation of Canada
The Thalassemia Foundation of Canada provides education, gives medical grants for research, and helps patients with unmet medical needs.

Thalassemia International Federation
This organization supports national thalassemia associations in their efforts to lobby for research and improved treatments, as well as to prevent affected births through education, genetic screening, and counseling.

U.K. Thalassaemia Society
This organization aims to be the definitive source of information, education, and research for those affected by or working with thalassaemia.

Centers for Thalassemia Treatment and Research

Each of these hospitals has a research and treatment program devoted to thalassemia:

Children's Healthcare of Atlanta

Children's Hospital Boston

Children's Hospital Los Angeles

Children's Hospital & Research Center Oakland

Children's Hospital of Philadelphia

Children's Medical Center Dallas

Texas Children's Hospital Houston

Children's Memorial Hospital Chicago

The Hospital for Sick Children (Toronto)

Weill Medical College of Cornell University

Books

Banks, A. 2009. Turning Blood Red: The Fight for Life in Cooley's Anemia. World Scientific Publishing Company, Singapore.

Cappellini M-D, Cohen A, Eleftheriou A, et al. 2008. Guidelines for the Clinical Management of Thalassaemia 2nd Edition Revised. Thalassaemia International Federation, Nicosia, Cyprus.

Eleftheriou, A. 2007. About Thalassaemia. Thalassaemia International Federation, Nicosia, Cyprus.

Journal Articles

Alpha Thalassemia

Higgs DR, Weatherall DJ. 2009. The alpha thalassaemias. Cell Mol. Life Sci. 66: 1154-1162.

Lok CY, Merryweather-Clarke AT, Viprakasit V, et al. 2009. Iron overload in the Asian community. Blood 114: 20-25.

Michlitsch J, Azimi M, Hoppe C, et al. 2009. Newborn screening for hemoglobinopathies in California. Pediatr. Blood Cancer 52: 486-490.

O'Donnell A, Premawardhena A, Arambepola M, et al. 2009. Interaction of malaria with a common form of severe thalassemia in an Asian population. Proc. Natl. Acad. Sci. USA. 106:18716-18721.

Olivieri NF, Muraca GM, O'Donnell A, et al. 2008. Studies in haemoglobin E beta-thalassaemia. Br. J. Haematol. 141: 388-397.

Premawardhena A, Arambepola M, Katugaha N, Weatherall DJ. 2008. Is the beta thalassaemia trait of clinical importance? Br. J. Haematol. 141: 407-410.

Singer ST, Kim HY, Olivieri NF, et al; Thalassemia Clinical Research Network. 2009. Hemoglobin H-constant spring in NorthAmerica: an alpha thalassemia with frequent complications. Am. J. Hematol. 84: 759-761.

Sollaino MC, Paglietti ME, Perseu L, et al. 2009. Association of alpha globin gene quadruplication and heterozygous beta thalassemia in patients with thalassemia intermedia. Haematologica 94: 1445-1448. Full Text

Weatherall DJ. 2008. Hemoglobinopathies worldwide: present and future. Curr. Mol. Med. 8: 592-599.

Gene Therapy

Arumugam PI, Urbinati F, Velu CS, et al. 2009. The 3' region of the chicken hypersensitive site-4 insulator has properties similar to its core and is required for full insulator activity. PLoS One 4: e6995. Full Text

Arumugam PI, Higashimoto T, Urbinati F, et al. 2009. Genotoxic potential of lineage-specific lentivirus vectors carrying the beta-globin locus control region. Mol. Ther. 17: 1929-1937.

Cartier N, Hacein-Bey-Abina S, Bartholomae CC, et al. 2009. Hematopoietic stem cell gene therapy with a lentiviral vector in X-linked adrenoleukodystrophy. Science 326: 818-823.

Hargrove PW, Kepes S, Hanawa H, et al. 2008. Globin lentiviral vector insertions can perturb the expression of endogenous genes in beta-thalassemic hematopoietic cells. Mol. Ther. 16: 525-533.

Hanawa H, Yamamoto M, Zhao H, et al. 2009. Optimized lentiviral vector design improves titer and transgene expression of vectors containing the chicken beta-globin locus HS4 insulator element. Mol. Ther. 17: 667-674.

Hayakawa J, Ueda T, Lisowski L, et al. 2009. Transient in vivo beta-globin production after lentiviral gene transfer to hematopoietic stem cells in the nonhuman primate. Hum. Gene Ther. 20: 563-572.

Kim YJ, Kim YS, Larochelle A, et al. 2009. Sustained high-level polyclonal hematopoietic marking and transgene expression 4 years after autologous transplantation of rhesus macaques with SIV lentiviral vector-transduced CD34+ cells. Blood 113: 5434-5443.

Lebensburger J, Persons DA. 2008. Progress toward safe and effective gene therapy for beta-thalassemia and sickle cell disease. Curr. Opin. Drug Discov. Devel. 11: 225-232.

May C, Rivella S, Callegari J, et al. 2000. Therapeutic haemoglobin synthesis in beta-thalassaemic mice expressing lentivirus-encoded human beta-globin. Nature 406: 82-86.

Perumbeti A, Higashimoto T, Urbinati F, et al. 2009. A novel human gamma-globin gene vector for genetic correction of sickle cell anemia in a humanized sickle mouse model: critical determinants for successful correction. Blood 114: 1174-1185.

Pestina TI, Hargrove PW, Jay D, et al. 2009. Correction of murine sickle cell disease using gamma-globin lentiviral vectors to mediate high-level expression of fetal hemoglobin. Mol. Ther. 17: 245-252.

Ryu BY, Evans-Galea MV, Gray JT et al. 2008. An experimental system for the evaluation of retroviral vector design to diminish the risk for proto-oncogene activation. Blood 111: 1866-1875.

Urbinati F, Arumugam P, Higashimoto T, et al. 2009. Mechanism of reduction in titers from lentivirus vectors carrying large inserts in the 3'LTR. Mol. Ther. 17: 1527-1536.

Zhao H, Pestina TI, Nasimuzzaman M, et al. 2009. Amelioration of murine beta-thalassemia through drug selection of hematopoietic stem cells transduced with a lentiviral vector encoding both gamma-globin and the MGMT drug-resistance gene . Blood 113: 5747-5756.

Stem Cell Transplantation

Bernardo ME, Zecca M, Piras E, et al. 2008. Treosulfan-based conditioning regimen for allogeneic haematopoietic stem cell transplantation in patients with thalassaemia major. Br. J. Haematol. 143: 548-551.

Caocci G, Pisu S, Argiolu F, et al. 2006. Decision-making in adult thalassemia patients undergoing unrelated bone marrow transplantation: quality of life, communication and ethical issues. Bone Marrow Transplant. 37: 165-169.

Fleischhauer K, Locatelli F, Zecca M, et al. 2005. Graft rejection after unrelated donor hematopoietic stem cell transplantation for thalassemia is associated with nonpermissive HLA-DPB1 disparity in host-versus-graft direction. Blood 107: 2984-2992. Full Text

Hollingsworth CL, Frush DP, Kurtzburg J, Prasad VK. 2008. Pediatric hematopoietic stem cell transplantation and the role of imaging. Radiology 248: 348-365.

Jaing TH, Hung IJ, Yang CP, Tsai MH, et al. 2009. Second transplant with two unrelated cord blood units for early graft failure after cord blood transplantation for thalassemia. Pediatr. Transplant. 13: 766-768.

Jaing TH, Chen SH, Tsai MH, et al. 2009. Transplantation of unrelated donor umbilical cord blood for nonmalignant diseases: a single institution's experience with 45 patients. Biol. Blood Marrow Transplant. Sep. 16. [Epub ahead of print]

Kurtzberg J, Prasad VK, Carter SL, et al; COBLT Steering Committee. 2008. Results of the Cord Blood Transplantation Study (COBLT): clinical outcomes of unrelated donor umbilical cord blood transplantation in pediatric patients with hematologic malignancies. Blood 112: 4318-4327. Full Text

La Nasa G, Argiolu F, Giardini C, et al. 2005. Unrelated bone marrow transplantation for beta-thalassemia patients: The experience of the Italian Bone Marrow Transplant Group. Ann. NY Acad. Sci. 1054: 186-195.

La Nasa G, Littera R, Locatelli F, et al. 2007. Status of donor-recipient HLA class I ligands and not the KIR genotype is predictive for the outcome of unrelated hematopoietic stem cell transplantation in beta-thalassemia patients. Biol. Blood Marrow Transplant. 13: 1358-1368.

Page KM, Mendizabal AM, Prasad VK, et al. 2008. Posttransplant autoimmune hemolytic anemia and other autoimmune cytopenias are increased in very young infants undergoing unrelated donor umbilical cord blood transplantation. Biol. Blood Marrow Transplant. 14: 1108-1117.

Parikh SH, Mendizabal A, Martin PL, et al. 2009. Unrelated donor umbilical cord blood transplantation in pediatric myelodysplastic syndrome: a single-center experience. Biol. Blood Marrow Transplant. 15: 948-955.

Prasad VK, Kurtzberg J. 2008. Emerging trends in transplantation of inherited metabolic diseases. Bone Marrow Transplant. 41: 99-108.

Sodani P, Isgro A, Gaziev J, et al. 2009. Purified T-depleted, CD34+ peripheral blood and bone marrow cell transplantation from haploidentical mother to child with thalassemia. Blood Nov. 6. [Epub ahead of print]

Fetal Hemoglobin switching

Chin J, Singh M, Banzon V, et al. 2009. Transcriptional activation of the gamma-globin gene in baboons treated with decitabine and in cultured erythroid progenitor cells involves different mechanisms. Exp Hematol. 37: 1131-1142.

Lettre G, Sankaran VG, Bezerra MA, et al. 2008. DNA polymorphisms at the BCL11A, HBS1L-MYB, and beta-globin loci associate with fetal hemoglobin levels and pain crises in sickle cell disease. Proc. Natl. Acad. Sci. USA 105: 11869-11874. Full Text

Lederer CW, Basak AN, Aydinok Y, et al. 2009. An electronic infrastructure for research and treatment of the thalassemias and other hemoglobinopathies: the Euro-mediterranean ITHANET project. Hemoglobin 33: 163-176.

Lonkar P, Kim KH, Kuan JY, et al. 2009. Targeted correction of a thalassemia-associated beta-globin mutation induced by pseudo-complementary peptide nucleic acids. Nucleic Acids Res. 37: 3635-3644.

Sankaran VG, Menne TF, Xu J, et al. 2008. Human fetal hemoglobin expression is regulated by the developmental stage-specific repressor BCL11A. Science 322:1839-1842. Full Text

Uda M, Galanello R, Sanna S, et al. 2008. Genome-wide association study shows BCL11A associated with persistent fetal hemoglobin and amelioration of the phenotype of beta-thalassemia. Proc. Natl. Acad. Sci. USA 105: 1620-1625. Full Text

Weinberg RS, Ji X, Sutton M, et al. 2005. Butyrate increases the efficiency of translation of gamma-globin mRNA. Blood 105: 1807-1809. Full Text

Iron Regulation

Breda L, Gardenghi S, Guy E, et al. 2005. Exploring the role of hepcidin, an antimicrobial and iron regulatory peptide, in increased iron absorption in beta-thalassemia. Ann. NY Acad. Sci. 1054: 417-422.

Fung EB, Harmatz P, Milet M, et al.; Multi-Center Study of Iron Overload Research Group. 2007. Morbidity and mortality in chronically transfused subjects with thalassemia and sickle cell disease: A report from the multi-center study of iron overload. Am. J. Hematol. 82: 255-265.

Fung EB, Harmatz PR, Lee PD, et al.; Multi-Centre Study of Iron Overload Research Group. 2006. Increased prevalence of iron-overload associated endocrinopathy in thalassaemia versus sickle-cell disease. Br. J. Haematol. 135: 574-582.

Gardenghi S, Marongiu MF, Ramos P, et al. 2007. Ineffective erythropoiesis in beta-thalassemia is characterized by increased iron absorption mediated by down-regulation of hepcidin and up-regulation of ferroportin. Blood 109: 5027-5035. Full Text

Hershko C. 2009. Iron overload in Asia. Blood 114: 1-2.

Hershko C. 2007. Mechanism of iron toxicity. Food Nutr. Bull. 28(4 Suppl):S500-S509.

Hershko C. 2007. Iron loading and its clinical implications. Am. J. Hematol. 82 (12 Suppl):1147-1148.

Libani IV, Guy EC, Melchiori L, et al. 2008. Decreased differentiation of erythroid cells exacerbates ineffective erythropoiesis in beta-thalassemia. Blood 112: 875-885. Full Text

Piga A, Longo F, Duca L, et al. 2009. High nontransferrin bound iron levels and heart disease in thalassemia major. Am. J. Hematol. 84: 29-33.

Rachmilewitz EA, Weizer-Stern O, Adamsky K, et al. 2005. Role of iron in inducing oxidative stress in thalassemia: Can it be prevented by inhibition of absorption and by antioxidants? Ann. NY Acad. Sci. 1054: 118-123.

Rechavi G, Rivella S. 2008. Regulation of iron absorption in hemoglobinopathies. Curr. Mol. Med. 8: 646-662.

Rivella S. 2009. Ineffective erythropoiesis and thalassemias. Curr. Opin. Hematol. 16: 187-194.

Ruivard M, Lainé F, Ganz T, et al. 2009. Iron absorption in dysmetabolic iron overload syndrome is decreased and correlates with increased plasma hepcidin. J. Hepatol. 50: 1219-1225.

Sadelain M, Boulad F, Galanello R, et al. 2007. Therapeutic options for patients with severe beta-thalassemia: the need for globin gene therapy. Hum. Gene. Ther. 18: 1-9.

Taher A, Hershko C, Cappellini MD. 2009. Iron overload in thalassaemia intermedia: reassessment of iron chelation strategies. Br. J. Haematol. Aug. 13. [Epub ahead of print]

Walter PB, Fung EB, Killilea DW, et al. 2006. Oxidative stress and inflammation in iron-overloaded patients with beta-thalassaemia or sickle cell disease. Br. J. Haematol. Oct;135(2):254-263. Full Text

Weizer-Stern O, Adamsky K, Amariglio N, et al. 2006. Downregulation of hepcidin and haemojuvelin expression in the hepatocyte cell-line HepG2 induced by thalassaemic sera. Br. J. Haematol. 135: 129-138.

Chelation

Cappellini MD, Taher A. 2009. Deferasirox (Exjade) for the treatment of iron overload. Acta Haematol. 122: 165-173.

Chirnomas D, Smith AL, Braunstein J, et al. 2009. Deferasirox pharmacokinetics in patients with adequate versus inadequate response. Blood 114: 4009-4013.

Evans RW, Rafique R, Zarea A, et al. 2008. Nature of non-transferrin-bound iron: studies on iron citrate complexes and thalassemic sera. J. Biol. Inorg. Chem. 13: 57-74.

Fischer R, Longo F, Nielsen P, et al. 2003. Monitoring long-term efficacy of iron chelation therapy by deferiprone and desferrioxamine in patients with beta-thalassaemia major: application of SQUID biomagnetic liver susceptometry. Br. J. Haematol. 121: 938-948.

Fung EB, Harmatz PR, Milet M, et al; Multi-Center Iron Overload Research Group. 2008. Disparity in the management of iron overload between patients with sickle cell disease and thalassemia who received transfusions. Transfusion 48: 1971-1980.

Galanello R, Campus S. 2009. Deferiprone chelation therapy for thalassemia major. Acta Haematol. 122: 155-164.

Liu DY, Liu ZD, Hider RC. 2002. Oral iron chelators--development and application. Best Pract. Res. Clin. Haematol. 15: 369-384

Neufeld EJ. 2006. Oral chelators deferasirox and deferiprone for transfusional iron overload in thalassemia major: new data, new questions. Blood 107: 3436-3441. Full Text

Porter JB, Taher AT, Cappellini MD, Vichinsky EP. 2008. Ethical issues and risk/benefit assessment of iron chelation therapy: advances with deferiprone/deferoxamine combinations and concerns about the safety, efficacy and costs of deferasirox. Hemoglobin 32: 601-607.

Taher A, Hershko C, Cappellini MD. 2009. Iron overload in thalassaemia intermedia: reassessment of iron chelation strategies. Br. J. Haematol. 147: 634-640.

Taher A, Cappellini MD, Vichinsky E, et al. 2009. Efficacy and safety of deferasirox doses of >30 mg/kg per d in patients with transfusion-dependent anaemia and iron overload. Br. J. Haematol. Sep 18. [Epub ahead of print]

Taher A, Cappellini MD. 2009. Update on the use of deferasirox in the management of iron overload. Ther. Clin. Risk Manag. 5: 857-868.

Telfer PT, Warburton F, Christou S, et al. 2009. Improved survival in thalassemia major patients on switching from desferrioxamine to combined chelation therapy with desferrioxamine and deferiprone. Haematologica Oct. 8. [Epub ahead of print]

Vichinsky E. 2008. Oral iron chelators and the treatment of iron overload in pediatric patients with chronic anemia. Pediatrics 121: 1253-1256. Full Text

Vichinsky E. 2008. Clinical application of deferasirox: practical patient management. Am. J. Hematol. 83: 398-402.

Voskaridou E, Plata E, Douskou M, et al. 2009. Treatment with deferasirox (Exjade((R))) effectively decreases iron burden in patients with thalassaemia intermedia: results of a pilot study. Br. J. Haematol. Oct. 26. [Epub ahead of print]

Walter PB, Macklin EA, Porter J, et al; Thalassemia Clinical Research Network. 2008. Inflammation and oxidant-stress in beta-thalassemia patients treated with iron chelators deferasirox (ICL670) or deferoxamine: an ancillary study of the Novartis CICL670A0107 trial. Haematologica 93: 817-825. Full Text

Iron imaging

Brewer CJ, Coates TD, Wood JC. 2009. Spleen R2 and R2* in iron-overloaded patients with sickle cell disease and thalassemia major. J. Magn. Reson. Imaging 29: 357-364.

Busca A, Falda M, Manzini P, et al. 2009. Iron overload in patients receiving allogeneic hematopoietic stem cell transplantation: quantification of iron burden by superconducting quantum interference device (SQUID) and therapeutic effectiveness of phlebotomies. Biol. Blood Marrow Transplant. Sep. 17. [Epub ahead of print]

Guo H, Au WY, Cheung JS, et al. 2009. Myocardial T2 quantitation in patients with iron overload at 3 Tesla. J. Magn. Reson. Imaging 30: 394-400.

Hankins JS, McCarville MB, Loeffler RB, et al. 2009. R2* magnetic resonance imaging of the liver in patients with iron overload. Blood 113: 4853-4855.

Kim D, Jensen JH, Wu EX, et al. 2009. Breathhold multiecho fast spin-echo pulse sequence for accurate R2 measurement in the heart and liver. Magn. Reson. Med. 62: 300-306.

Kirk P, Roughton M, Porter JB, et al. 2009. Cardiac T2* magnetic resonance for prediction of cardiac complications in thalassemia major. Circulation Oct. 2. [Epub ahead of print]

Noetzli LJ, Papudesi J, Coates TD, Wood JC. 2009. Pancreatic iron loading predicts cardiac iron loading in thalassemia major. Blood 114: 4021-4026.

St Pierre TG, Clark PR, Chua-anusorn W, et al. 2005. Noninvasive measurement and imaging of liver iron concentrations using proton magnetic resonance. Blood 105: 855-861. Full Text

Wood JC, Enriquez C, Ghugre N, et al. 2005. MRI R2 and R2* mapping accurately estimates hepatic iron concentration in transfusion-dependent thalassemia and sickle cell disease patients. Blood 106: 1460-1465. Full Text

Issues for Older Adults

Fung EB, Harmatz PR, Milet M, et al; Multi-Center Iron Overload Study Group. 2008. Fracture prevalence and relationship to endocrinopathy in iron overloaded patients with sickle cell disease and thalassemia. Bone 43: 162-168. Full Text

Origa R, Piga A, Quarta G, et al. 2009. Pregnancy and {beta}-thalassemia: an Italian multicenter experience. Haematologica Nov. 10. [Epub ahead of print] Full Text

Scacchi M, Danesi L, Cattaneo A, et al. 2009. The pituitary-adrenal axis in adult thalassaemic patients. Eur. J. Endocrinol. Oct. 9. [Epub ahead of print]

Taher AT, Musallam KM, Nasreddine W, et al. 2009. Asymptomatic brain magnetic resonance imaging abnormalities in splenectomized adults with thalassemia intermedia. J. Thromb. Haemost. Oct. 11. [Epub ahead of print]

Terpos E, Voskaridou E. 2008. Interactions between osteoclasts, osteoblasts and immune cells: implications for the pathogenesis of bone loss in thalassemia. Pediatr. Endocrinol. Rev. 6 Suppl 1: 94-106.

Vogiatzi MG, Macklin EA, Trachtenberg FL, et al.; Thalassemia Clinical Research Network. 2009. Differences in the prevalence of growth, endocrine and vitamin D abnormalities among the various thalassaemia syndromes in North America. Br. J. Haematol. 146: 546-556.

Vogiatzi MG, Macklin EA, Fung EB, et al.; Thalassemia Clinical Research Network. 2009. Bone disease in thalassemia: a frequent and still unresolved problem. J. Bone Miner. Res. 24: 543-557.

Voskaridou E, Terpos E. 2008. Pathogenesis and management of osteoporosis in thalassemia. Pediatr. Endocrinol. Rev. 6 Suppl 1: 86-93.

Voskaridou E, Christoulas D, Konstantinidou M, et al. 2008. Continuous improvement of bone mineral density two years post zoledronic acid discontinuation in patients with thalassemia-induced osteoporosis: long-term follow-up of a randomized, placebo-controlled trial. Haematologica 93: 1588-1590. Full Text

Voskaridou E, Plata E, Douskou M, et al. 2009. Treatment with deferasirox (Exjade((R))) effectively decreases iron burden in patients with thalassaemia intermedia: results of a pilot study. Br. J. Haematol. Oct. 26. [Epub ahead of print]

Voskaridou E, Christoulas D, Xirakia C, et al. 2009. Serum Dickkopf-1 is increased and correlates with reduced bone mineral density in patients with thalassemia-induced osteoporosis. Reduction post-zoledronic acid administration. Haematologica 94: 725-728. Full Text

Nutrition and antioxidants

Fung EB, Harmatz PR, Milet M, et al; Multi-Center Iron Overload Study Group. 2008. Fracture prevalence and relationship to endocrinopathy in iron overloaded patients with sickle cell disease and thalassemia. Bone 43: 162-168. Full Text

Vogiatzi MG, Macklin EA, Trachtenberg FL, et al; Thalassemia Clinical Research Network. 2009. Differences in the prevalence of growth, endocrine and vitamin D abnormalities among the various thalassaemia syndromes in North America. Br. J. Haematol. 146: 546-556.

Sponsors

Presented by

Platinum

This program was supported by an educational grant from Novartis Oncology

Academy Friends

Ferrokin BioSciences

HemaQuest Pharmaceuticals, Inc.

Juvenon

Resonance Health

The project described was supported by Award Number R13HL096359 from the National Heart, Lung, And Blood Institute, and The National Institute Of Diabetes And Digestive And Kidney Diseases. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Heart, Lung, And Blood Institute or the National Institutes of Health.

Speakers:
Susan P. Perrine, Boston University School of Medicine, US
Joanna Y. Chin, Yale University School of Medicine, US
Thomas M. Ryan, University of Alabama at Birmingham, US
Derek A. Persons, St. Jude Children's Research Hospital, US
Frank Grosveld, Erasmus Medical Center, NL
Stuart Orkin, Children's Hospital Boston, US

Going back to start

Prior to birth, the fetus makes a form of hemoglobin known as fetal hemoglobin (hemoglobin F or γ-globin). At birth, the γ-globin gene expression switches off and adult β-globin is produced. Studies show that γ-globin is capable of carrying the oxygen that adults need, so researchers have long wondered if restoring γ-globin either via gene therapy or pharmaceutical methods could provide therapeutic relief to β-thalassemia patients.

Fetal-to-adult hemoglobin switching in humans and mice.

Therapeutic drugs are capable of inducing fetal globin expression by 1 to 5 grams/dL above baseline. One such agent is butyrate, which has been shown to eliminate transfusion requirements in some transfusion-dependent individuals. The hormone erythropoietin (EPO) in combination with butyrate can provide benefit in some patients, especially those with low endogenous EPO levels. A new oral fetal globin inducer, HQK-1001, is being tested in clinical trials, reported Susan P. Perrine of Boston University School of Medicine. It stimulates fetal globin induction by acting on the proximal promoter of the γ-globin gene. It also has erythropoietic-stimulatory effects.

Another way to revive γ-globin expression may be by using triplex-forming peptide nucleic acids (PNAs), reported Joanna Y. Chin of Yale University School of Medicine. PNAs are nucleobases that are linked to a peptide-like backbone. PNAs can bind to DNA and provoke recombination and repair at nearby sites. Chin has shown that these PNAs can induce heritable elevations in γ-globin gene expression.

The ability to study fetal to adult hemoglobin switching has been hampered by the lack of a γ-globin equivalent in mice. A new mouse model has been developed by Thomas M. Ryan of the University of Alabama at Birmingham that mimics Cooley's anemia and the switch from human fetal γ-globin to adult β-globin gene expression. Such novel humanized mouse models will help researchers develop transfusion and iron chelation therapies, study iron homeostasis, induce fetal hemoglobin expression, and test genetic and cell-based therapies for the correction of thalassemia.

While some gene therapy approaches have aimed at restoring functional β-globin, others are aimed at restoring the expression of γ-globin genes through gene therapy. Derek A. Persons of St. Jude Children's Research Hospital in Memphis and his team is attempting to permanently raise fetal hemoglobin levels by introducing an erythroid-specific γ-globin lentiviral vector into hematopoietic stem cells. The team is currently testing the vector gene transfer in primates in preparation for a clinical trial.

To better understand how to use gene therapy to control γ-globin gene expression, Frank Grosveld of Erasmus Medical Center in the Netherlands is exploring how γ-globin expression is regulated at the molecular level. Grosveld's group is using a novel strategy to find proteins bound to the repressed γ-globin promoter in vivo. The repressing factors are not known, but their removal would unlock γ-globin expression. Grosveld's group has detected seven factors that bind to the γ-globin promoter. They then tried to knock down those factors to see whether they could revive γ-globin expression. Knocking down five of them had a positive effect on fetal hemoglobin production, and two had no effect on γ-globin gene activation.

Stuart Orkin and his colleagues at Children's Hospital Boston in collaboration with others have used genome wide association to identify a γ-globin repressor known as BCL11A. In BCL11A knockout mice, loss of BCL11A leads to expression of mouse embryonic globin. When BLC11A is suppressed in adult-type human erythroid cells, the result is reactivation of γ-globin gene transcription. (Sankaran VG, 2009). Further study of BCL11A may provide a means of reactivating fetal hemoglobin.

Speakers:
Mark C. Walters, Children's Hospital & Research Center, US
Vinod K. Prasad, Duke University Medical Center, US
Antonella Isgrò, University of Rome, IT

A new start

Allogeneic hematopoietic stem cell (HSC) transplantation offers the only proven cure for β-thalassemia. The success of transplantation hinges on the immunocompatibility of donor and recipient. The disease-free survival rate is greatest when the donor and recipient have identical human-leukocyte antigens (HLA) on their red blood cells. Only about 30% to 40% of thalassemic patients have a sibling donor who is both HLA-matched and β-thalassemia- free.

To date, most successful transplantations have been in young children, where the success rate (β-thalassemia-free survival) is roughly 95%. Most transplantation recipients received HLA-identical sibling allografts after preparation (conditioning) with myeloablative drugs (usually busulfan and cyclophosphamide) to kill the patient's existing HSCs. Drugs such as cyclosporine and methylprednisolone are given to prevent graft versus host disease (GvHD).

Transplantation to unmatched individuals is expanding as new discoveries in how to overcome HLA disparity and control GvHD are made, said Mark C. Walters of Children's Hospital & Research Center, Oakland. New sources of HSCs, such as umbilical cord blood and unmatched bone marrow donations, are making the technology available to a wider array of patients.

Umbilical cord blood transplantation and unrelated bone marrow transplantation

Compared to adult blood, umbilical cord blood has more abundant naïve T cells and fewer suppressor T cells, so it is less likely to cause GvHD. Over 500,000 units of umbilical cord blood are available worldwide. More than 90% of patients will find a donor who is identically matched in 4 of the 6 HLA proteins. However, patients have only a 20% chance of finding a 6 out of 6 match from an unrelated cord blood donor. More than 10,000 unrelated cord blood transfers have been done worldwide, but only 100 β thalassemia patients have undergone this procedure.

Cord blood is collected from newborns, so each cord blood donation consists of a relatively small number of cells, especially when compared to the number of bone marrow cells that can be collected from adult donors. Since only a small number of cells are transplanted, cord blood HSCs take a long time to repopulate the patient's marrow, leaving the patient vulnerable to bleeding and infection after transplant. Of 47 unrelated cord blood transplantations performed between July 2001 and January 2006, 38 of 51 patients survived (75%), and 11 had graft failure or recurrent thalassemia (22%). Transplant-related mortality was 13.7% (Jaing TH, 2008).

Unrelated umbilical cord blood transplantation is most successful early in life before thalassemia-related complications arise, said Vinod K. Prasad of Duke University Medical Center. It can be performed in infancy without any negative impact on the outcome (Prasad VK, 2008). A number of strategies may be able to address the low number of cells, said Prasad, including combining cord blood from multiple donors, infusing other types of cells in addition to the cord blood cells, injecting the cord blood cells directly into the marrow, and selection and priming of stem cells.

HLA matching is important for patient survival in unrelated donor (URD) transplantations. In a study of 45 individuals ages 2 to 26 years old (median 12.4 years) treated by URD bone marrow transplantation between 1995 and 2005, overall survival was 87%, disease-free survival was 71%, and transplant related mortality was 13%. (La Nasa, 2007)

Factors that affect transplantation

The factors that affect transplantation success most are chelation history, hepatomegaly (enlarged liver), and liver fibrosis. Transplantation candidates can be put into risk categories according to these factors as follows:

New preparative regimens and the control of transplant-related complications have improved the success rate of HSC transplantation in recent years, reported Antonella Isgrò of the University of Rome. Young people are more susceptible to excessive rejection, older people to excessive toxicity, said Isgrò. By adjusting the treatment regimens to reduce rejection in young people and reduce toxicity in older people, the researchers have been able to improve disease-free survival probability from 58% to 80% in class 3 pediatric patients while disease-free survival in class 3 adults remained roughly the same but toxicity declined. In a multiracial population in Rome, disease-free survival averaged 90% for class 1 patients, 84% for class 2 patients, and 81% for class 3 patients, findings that are similar to what other transplant centers have reported. Results of unrelated BMT in Class 1 and Class 2 patients are comparable to those obtained in matched related transplants, said Isgrò.

For children with no matched donor, one option is haploidentical mother-to-child donation (Sodani P, 2009). A haploidentical mother will have at least half the matched antigens as her child. Immuno-tolerance established during the pregnancy will help to bypass the HLA disparity, said Isgrò. In 25 transplantations from maternal unmatched donors, overall survival was 91% and disease-free survival was 66%. The primary problem with mismatched HLA transplantation is delayed immune reconstitution, leaving patients susceptible to life-threatening infections.

Speakers:
Philippe Leboulch, CEA, Institute of Emerging Diseases and Innovative Therapies (iMETI), FR
Michel Sadelain, Memorial Sloan Kettering Cancer Center, US
Punam Malik, Cincinnati Children's Hospital Medical Center, US
David M. Bodine, National Institutes of Health, US
Laura Breda, Weill Cornell Medical College, US
Evangelia Yannaki, George Papanicolaou Hospital, GR

Targeting the root cause of Cooley's anemia

Gene therapy presents the opportunity to correct the defective β-globin gene using the patient's own stem cells. In this procedure, the patient's hematopoietic stem cells (HSCs, CD34⁺ cells) are collected from the bone marrow and transduced ex vivo with a viral vector expressing a competent γ- β-, or modified β-globin gene (e.g., βA-T87Q). The cells are then infused back into the blood, and they find their way to the marrow. HSCs that take up residence in the bone marrow begin differentiating into red blood cells carrying the competent β-globin protein.

Gene therapy has been shown to cure β-thalassemia in mouse models of the disease (e.g., May C, 2000), but only in the last two years has the procedure been attempted in humans. Philippe Leboulch of CEA, Institute of Emerging Diseases and Innovative Therapies (iMETI), presented results of gene therapy in a single patient, an 18 year-old male with severe βE/β⁰ thalassemia.

A potential complication with gene therapy is that the gene will insert into a region of the patient's genome near an oncogene that may be activated as a result. In a previous gene therapy trial for SCID-X1 disease, some of the children in the trial developed leukemia.

To find out whether the βA-T87Q gene inserted near any oncogenes, Leboulch's team did a genome-wide analysis. They found that the vector inserted into about 300 integration sites throughout the genome, and that the most common insertion site was within the HMGA2 gene, which is associated with oncogenesis.

Researchers do not know if the vector insertion will cause HMGA2 to be transcribed, which could lead to cell growth. The researchers did find evidence of aberrant splicing that could contribute to HMGA2 transcription. In the 28 months post-transfusion, the proportion of cells with vector insertion in the HMGA2 gene has stabilized over time.

The researchers had designed the vector with safety features to prevent the unwanted activation of genes such as HMGA2. The vector included regions known as "insulators," which are DNA elements near chromatin boundaries with two properties: barrier activity and enhancer blocker activity. Barrier activity blocks the spread of heterochromatin, thereby preventing silencing of the βA-T87Q gene. Enhancer blocking activity prevents the vector from activating an adjacent promoter that would cause unwanted expression of a gene such as HMGA2. In preclinical mouse studies, the vector did not insert into the HMGA2 gene.

Insulator blocks gene silencing and unwanted enhancement of non-targeted genes.

In this patient, however, the insulators failed to prevent vector insertion in the HMGA2 gene. Despite these unwanted insertions, the βAT87Q gene is being expressed in about 13% of the cells in the bone marrow and about 8.5% of the cells in the peripheral blood. The expression of the vector was largely restricted to embryonic and stem cells.

The clinical outcome for the patient has so far been favorable. Twenty-eight months after the transplantation, the patient is transfusion-independent. About one-third of the β-globin in the plasma was made by the βA-T87Q gene. (A second patient who underwent the gene therapy procedure has, however, required transfusions.)

A multinational clinical trial using a similar vector will begin next year under the guidance of Michel Sadelain and his colleagues at Memorial Sloan Kettering Cancer Center in New York. Sadelain's team has optimized the viral vector for safety and efficacy. No cases of leukemia have been found in large cohorts of mice that have received the vector. Based on these safety studies and other data, a multinational clinical trial has been approved by regulatory agencies.

Vector design

An ideal globin vector would express β-like globin protein at high levels, feature compact regulatory elements for higher initial titer, contain no enhancer elements that could unintentionally activate oncogenes or contain an enhancer plus an enhancer blocker, and finally, contain barrier elements to prevent gene silencing.

The design of better insulators could improve gene therapy. Punam Malik at the Cincinnati Children's Hospital Medical Center is studying the insulator known as the chicken hypersensitive element 4 (cHS4) element, which blocks the spread of heterochromatin towards the globin loci and thus prevents gene silencing. The large size of the cHS4 element, however, results in low lentiviral titers. Malik's group wondered if it were possible to raise these titers by using a smaller insulator made up of only the active regions of the 1.2 Kb cHS4 element. The researchers found that the 5′ 250 base-pair core and the 3′ 400 base-pair region were essential for insulator activity. The Malik team found that vectors containing an optimized 650bp cHS4 have higher, more uniform expression than those containing the full 1.2 Kb insulator. The 650 bp cHS4 has maximal enhancer blocking effect with reasonable viral titers.

The vector used in the trial described above contains enhancer elements from the β-globin locus control region (LCR) to increase β-globin gene expression. However, the use of the LCR makes the vector subject to recombination, cryptic splicing, and aberrant polyadenylation, resulting in low levels of transduction. Instead, David M. Bodine of the National Institutes of Health and his colleagues are working on new vector designs. One avenue they are exploring is the use of the human ankyrin (ANK-1E) promoter, which has no enhancer element but can direct the expression of γ-globin (fetal globin) genes. The ANK-1E promoter does contain a barrier element that can prevent gene silencing. The ankyrin element might improve transcription and translation of the β-globin gene, said Laura Breda, a postdoctoral researcher in the lab of Stefano Rivella at Weill Cornell Medical College.

HSC mobilization

For gene therapy to be effective, the transduction efficacy needs to be increased. Collecting greater numbers of HSCs would be helpful in this regard. One strategy for doing this is to induce the cells to leave the bone marrow and enter the blood where they can be easily collected. One agent used for mobilizing cells is granulocyte colony stimulating factor (G-CSF), a cytokine that stimulates the bone marrow to release granulocytes and HSCs. However, G-CSF can increase the risk of splenic rupture or thrombosis, especially in splenectomized patients. Evangelia Yannaki of George Papanicolaou Hospital in Thessaloniki, Greece, found that hydroxyurea given 12 days or more prior to G-CSF seems to protect splenectomized patients by controlling excessive leukocytosis during mobilization and by reducing thrombocytosis before G-CSF. In non-splenectomized patients, mobilization is safe and results in adequate numbers of CD34⁺ cells.

Speakers:
Sylvia Titi Singer, Children's Hospital and Research Center Oakland, US
Claudia R. Morris, Children's Hospital and Research Center Oakland, US
Maria Domenica Cappellini, University of Milan, IT
Caterina Borgna-Pignatti, University of Ferrara, IT
Evangelos Terpos, University of Athens School of Medicine, GR
Ashutosh Lal, Children's Hospital and Research Center Oakland, US
Ellen B. Fung, Children's Hospital and Research Center Oakland, US
Elizabeth C. Theil, Children's Hospital Oakland Research Institute, US
Vivekanandan Thayalasuthan, Toronto General Hospital, CA
David Weatherall, University of Oxford, UK
Elliott Vichinsky, Children’s Hospital & Research Center in Oakland, US

Reproductive problems

Reproductive problems affect about 23% to 55% of adult female thalassemics, said Sylvia Titi Singer of Children's Hospital and Research Center Oakland. They may suffer from delayed puberty, primary or secondary amenorrhea, irregular menstrual cycles, and secondary effects of low estrogen. Most likely these problems result from impairments in the hypothalamic-pituitary-gonadal axis, pituitary hyporesponsiveness to gonadotropin releasing hormone, decreased hormone storage due to cell degranulation, and loss of anterior pituitary tissue. They may also be suffering from damage to the ovaries or sperm from severe iron overload.

Little is known about whether chelators can prevent or delay pituitary hormone depletion, how much iron causes pituitary failure, and when to intervene for fertility preservation. Most researchers have found that these reproductive changes are not reversible even with adequate chelation. Although reproductive assistance is required for about 50% of women wishing to conceive, most patients report the delivery of normal babies.

Titi Singer found that in the women she studied, 48% had gonadotrophic-gonadal axis dysfunction as seen by low levels of the luteinizing hormone, follicle stimulating hormone, and estradiol. She also noted that primary ovarian dysfunction is also present in about 28% of the women. Fertility showed some correlation with iron overload but this needs to be confirmed. Titi Singer stressed the need for hematologists to discuss fertility with their patients.

Pulmonary hypertension

Pulmonary hypertension is recognized as a serious health problem in adults with thalassemia intermedia. In thalassemia major, the exact prevalence is not certain because the disease often goes unrecognized. Roughly 60% to 75% of adult thalassemia major and intermedia patients have pulmonary hypertension (PH), said Claudia R. Morris of Children's Hospital and Research Center Oakland. PH is caused by the interaction of platelets, coagulation, erythrocytes, and endothelial cells, as well as inflammatory cytokines and vascular mediators. Low nitric oxide bioavailability, excess arginase activity, iron overload, and chronic hemolysis may also contribute to PH development, and splenectomy is a strong risk factor in hemolytic anemias and thalassemia intermedia. Guidelines are needed to help clinicians manage PH, and currently an NIH-sponsored trial in the Thalassemia Clinical Research Network is recruiting patients to evaluate the potential use of sildenafil (Viagra), which is FDA-approved for non-thalassemic PH, in thalassemic patients with the condition.

Thrombosis and stroke

Adult thalassemics are also at higher risk of thrombosis and stroke, said Maria Domenica Cappellini of the University of Milan. Conventional tests have failed to identify patients at risk, perhaps because these tests miss the contributory effect that platelets, leukocytes, and red blood cells may have on the hemostatic unbalance leading to thrombosis. Evaluation of coagulation in whole blood by thromboelastometry may be beneficial in identifying at risk patients, especially in splenectomized patients (Tripodi A, 2009).

Stroke is far more common in thalassemia patients than was previously recognized, said Cappellini. Asymptomatic brain damage was found in 86.7% of patients as detected by MRI or PET scans (Taher AT, 2009). Venous thrombosis is more prevalent in splenectomized thalassemia intermedia patients who are not regularly transfused. The protective effect of splenectomy may be due to decreased numbers of damaged red blood cells that coagulate and clog organs and circulation.

The available data on the use of anticoagulants and antiplatelet therapies in β thalassemia are either lacking or involve small, relatively low-quality studies. Cappellini and colleagues found that thalassemia intermedia patients who had already experienced a thromboembolytic event and received aspirin afterwards had a lower recurrence rate compared with those who were not taking aspirin, although the differences were not statistically significant.

Caterina Borgna-Pignatti of the University of Ferrara is exploring the genetic basis for disease severity in thalassemia intermedia and the role of genetic modifiers in the development of complications such as thrombosis, osteoporosis, and cardiac disease.

Osteoporosis

Thalassemia patients are at higher risk than the general public of suffering from osteoporosis, said Evangelos Terpos of the University of Athens School of Medicine. One of the causative factors appears to be osteoblast dysfunction, which may be influenced by Dkk-1. Insulin-like growth factor-1 also plays an important role. New data suggest that the reduced osteoblastic activity, which is believed to be the basic mechanism of bone loss in thalassemia, is accompanied by a comparable or even greater increase in bone resorption through the RANK/RANKL/OPG pathway.

Early detection via monitoring bone mineral density (BMD) is essential, said Terpos. Treatment with bisphosphonates (zoledronic acid at a dose of 4 mg every 3 months) effectively restores BMD and reduces pain in thalassemia patients with osteoporosis. Terpos and colleagues have shown that 1 year of treatment with zoledronic acid provides BMD and pain benefits that continue for at least 2 years after completion of therapy. The use of novel antiresorptive agents (denosumab/anti-RANKL) is currently being explored.

Nutrition and antioxidants

Antioxidant supplements could help improve the health of thalassemia patients. Thalassemia patients suffer from increased oxidative stress, which can cause lipid peroxidation, protein oxidation, and DNA oxidation. Oxidative stress also negatively affects the mitochondrial respiratory chain and causes immune system dysfunction. In mice, mitochondrial injury has been shown to cause reduced muscle contractility. Additionally, thalassemic patients have an altered plasma amino acid profile, indicating alterations in protein oxidation. Reduced glutathione may be a suitable marker to study the efficacy of antioxidant therapies. Citrulline levels may prove useful as a biomarker of mitochondrial dysfunction.

Supplemental antioxidants (vitamin E, vitamin C, selenium, and β-carotene) are not a substitute for effective chelation therapy, advised Ashutosh Lal of Children's Hospital and Research Center Oakland. Several pathological effects of oxidative stress can be reversed with chelators (e.g., mitochondrial injury and innate immune dysfunction). This leads to the speculation that combining antioxidant therapy with chelation will be more effective than chelation therapy alone. For example, in one study vitamin C plus DFO resulted in a marked improvement in iron excretion. Other potential antioxidants include silymarin (milk thistle), curcumin (spice), green tea, and carnitine (an amino acid).

A number of nutritional deficiencies have been noted in thalassemic patients, said Ellen B. Fung of Children's Hospital and Research Center Oakland. Thalassemic patients require more nutrients for growth and they have increased energy expenditure than non-thalassemics. This is due to increased oxidative stress related to iron overload, sequestration of trace minerals in the liver, increased urinary losses, and possibly reduced absorption of nutrients. Dietary vitamin D intake may be insufficient because patients are likely to be lactose intolerant. In one study of 361 thalassemics, only 18% had sufficient levels of vitamin D. Other important micronutrients are Vitamin A, B1, C, E, selenium, and zinc. Elizabeth C. Theil of Children's Hospital Oakland Research Institute discussed decreasing nutritional iron uptake by eating ferritin-rich (whole legume) foods, since the absorption mechanism is different than for iron salts or heme. 85% to 90% of the iron in beans is in ferritin.

Disparities in care

Thalassemia is a worldwide health concern and treatment is often suboptimal. Vivekanandan Thayalasuthan of Toronto General Hospital described the disparity of care that Hemoglobin E/βo-thalassemia patients receive in Sri Lanka, where medical care is correlated with what part of the country patients live in and whether they have the means to pay for care. This lack of uniform access to care makes documenting the prevalence of β-thalassemia and related disorders in developing countries very difficult, said David Weatherall of the University of Oxford. Citing India as an example, Weatherall said that "micromapping" was needed rather than relying on official numbers, which may have missed affected individuals in rural areas.

Alpha-thalassemia is a public health issue that is growing in North America, and newborn and couple screening should be required, said Elliott Vichinsky of Children’s Hospital & Research Center in Oakland. Prenatal diagnosis of homozygous α-thalassemia can be corrected by intrauterine bone marrow transplantation.

Speakers:
Tim St. Pierre, University of Western Australia, AU
Gary M. Brittenham, Columbia University, US
John Malcolm Walker, University College Hospital London, UK
Maria Marsella, University of Ferrara, IT
John C. Wood, Children's Hospital of Los Angeles, US
Robert C. Hider, King's College London, UK

Imaging using MRI

Advances in imaging methods using MRI have allowed researchers to diagnose iron overload and track improvements due to chelation. MRI uses strong magnetic fields and radio frequency pulses to induce the lining up of protons in the same direction inside the body. The time (T) it takes for the protons to return to random positions gives an indication of how much iron is present. Alternately the measurements can be stated as the rate (R) of decay. The signal is called T2 or T2* (or R2 or R2*) depending on the method of image acquisition.

The liver is perhaps the first place that iron begins to build up. When a certain liver iron concentration (LIC) threshold is reached, iron begins accumulating in the heart. But some patients treated with aggressive chelation can have more iron in the heart than the liver after months or years of treatment. Elevated LIC is linked to greater long-term risk of cardiac complications and premature death. Measuring LIC via MRI has advantages over biopsy because iron is distributed unevenly throughout the liver and fibrosis and cirrhosis exacerbate the problem, said Tim St. Pierre of the University of Western Australia. But MRI is not always accurate in heavily iron-loaded livers because the protons return to random positions very rapidly, making it difficult to get a good T or R signal.

One way to improve accuracy is by making an estimate of the baseline density of protons (known as the spin density). This "spin density projection" method was tested for its ability to accurately measure LIC in 125 β-thalassemia patients and found to perform better than biopsy in a blinded multi-center study (Hankins JS, 2009).

MRI signals showing increasing liver iron concentration (LIC)

Imaging the heart

In the heart, patients receiving transfusions tend to accumulate iron intracellularly as ferritin iron, which is soluble and rapidly mobilizable, or hemosiderin iron, which is insoluble and aggregated and serves as a long-term reserve. The MRI technique in use today, known as R2*, predominantly measures hemosiderin iron. Another technique, R2, measures both hemosiderin- and ferritin-bound iron. Measuring ferritin-bound iron alone is desirable because ferritin-bound iron is in equilibrium with the cytosolic iron pool, which can rapidly release iron with chelation.

A new technique called fast spin echo-sequence permits the calculation of RR2, a reduced transverse relaxation rate that provides a measurement of ferritin iron without hemosiderin iron, said Gary M. Brittenham of Columbia University. This technique can detect changes in myocardial ferritin iron after one week of iron-chelating therapy (Kim D, 2009).

Although MRI is a useful imaging technique, John Malcolm Walker of the University College Hospital London reminded the audience that the echocardiogram is a low-cost and valuable tool in assessing heart function in patients with β-thalassemia. Maria Marsella of the University of Ferrara in Italy used MRI to evaluate the role of female gender on cardiac iron overload by means of MRI.

Storage in endocrine organs

Roughly half of β-thalassemia patients suffer from hypogonadotropic hypogonadism and 10% suffer from hypothyroidism. 14% suffer from diabetes mellitus (Vogiatzi MG, 2009). It is now possible to use MRI to monitor iron overload in endocrine organs, said John C. Wood of Children's Hospital of Los Angeles. The pancreas can be measured using either R2 or R2*. For the pituitary gland, spin echo techniques are most robust. Both iron-loading and pituitary size predict pituitary function. Wood and his colleagues have found that pituitary R2 is highly correlated with LIC in children and young adults. Pituitary volume is diminished in thalassemia patients independent of iron, suggesting that oxidative stress plays a role.

NTBI

Until now, MRI has been unable to measure non-transferrin bound iron (NTBI), which builds up when transferrin is saturated. Unbound iron is more toxic because it promotes the generation of free radicals, propagators of oxidative damage. This oxidative damage includes mitochondrial membrane potential, respiratory enzyme activity, increased lysosomal fragility, lipid peroxidation, and apoptosis. Robert C. Hider of King's College London discussed a novel fluorescence-based method for measuring NTBI.

Speakers:
Chaim Hershko, Shaare Zedek Medical Center, IL
Sara Gardenghi, Weill Cornell Medical College, US
Elizabeta Nemeth, UCLA David Geffen School of Medicine, US
Mark D. Fleming, Children's Hospital Boston, US
Paula Fraenkel, Harvard Medical School, US
Stefano Rivella, Weill Cornell Medical College, US
Luca Melchiori, Weill Cornell Medical College, US

More is not merrier

Iron is used throughout the body in a number of enzymes and as an oxygen carrier in hemoglobin. Normally iron is ingested, absorbed into the gastrointestinal tract, localized to the liver where it is attached to the transporter molecule transferrin, and then transported to the red blood cells in the circulation. It is then recycled and any excess is released in the liver, heart, and endocrine glands, said Chaim Hershko of Shaare Zedek Medical Center in Israel. A better understanding of iron regulation could lead to other means of controlling iron levels.

Hepcidin is a key regulator of how much iron is absorbed from the diet. This small peptide hormone is produced by hepatocytes in the liver and circulates in the blood. When plasma iron levels drop, hepcidin production decreases, allowing iron into the body, said Elizabeta Nemeth of the UCLA David Geffen School of Medicine. When plasma iron levels are high, hepcidin production increases to block iron from entering the blood from the diet (Ruivard M, 2009).

Hepcidin regulates iron absorption from the duodenum.

Hepcidin is regulated not only by plasma iron levels but also by erythropoiesis. When many red blood cells are being made, hepcidin production is downregulated so that more iron is available for hemoglobin synthesis.

Transfusion status also affects hepcidin. The bodies of non-transfused individuals are trying to make red blood cells to make up for defective ones, so these individuals have suppression of hepcidin, allowing excessive absorption and iron overload. Transfused patients have many erythrocytes from the transfusion, so they have less need for erythropoiesis. Thus, hepcidin levels are adequate and these patients can block iron uptake more easily.

Hepcidin diagnostics may help stratify patients for the risk of iron toxicity, and hepcidin agonists may help restore iron homeostasis in thalassemia patients, especially those not requiring transfusions, said Nemeth. Nemeth's group is developing small molecule agonists that could bind to hepcidin's receptor, ferroportin.

Non-transfused individuals may benefit from having more hepcidin so that they could keep iron from entering the blood. In a mouse model of β thalassemia, overexpression of the hepcidin gene had beneficial effects on liver and spleen iron levels, according to Sara Gardenghi, a postdoctoral researcher at Weill Cornell Medical College.

One known modifier of hepcidin is hepatocyte-specific transmembrane serine protease 6 (TMPRSS6), said Mark D. Fleming of Children's Hospital Boston. People with mutations in the TMPRSS6 gene have lifelong iron deficiencies because absence of the protease causes an increase in hepcidin. Studies suggest that TMPRSS6 acts functionally upstream of hemojuvelin (HJV) in the bone morphogenetic protein (BMP) signaling pathway to negatively regulate hepcidin production. Some researchers, including Paula Fraenkel of Harvard Medical School, are developing the zebra fish embryo as a model for the identification and characterization of genetic pathways regulating iron metabolism.

Role of Jak2 in erythropoiesis

In individuals with Cooley's anemia, the body employs mechanisms to boost erythropoiesis and increase iron absorption. Anemia triggers production of the hormone erythropoietin (EPO) that, through the EpoR/Jak2/Stat pathway, triggers erythroid cell proliferation. Stefano Rivella and his team at Weill Cornell Medical College hypothesize that the Jak2 protein kinase plays a major role in ineffective erythropoiesis. Rivella's group showed that β thalassemic individuals have a larger than normal number of erythroid cells in which Jak2 is active.

A Jak2 inhibitor TG101209 was effective at decreasing ineffective erythropoiesis and splenomegaly in two mouse models of β-thalassemia intermedia, reported Luca Melchiori, a postdoctoral researcher in Rivella's lab, suggesting that Jak2 inhibitors can limit the expansion of the proliferating pool of erythroid cells with beneficial affects on splenomegaly. Rivella speculated that inhibiting Jak2 might be linked to increased hepcidin synthesis, which would be desirable because it would block absorption of iron from the gut as well as release of iron from macrophages.

Consequences of β-thalassemia.

Children born with Cooley's anemia (also called β-thalassemia major) once faced a life expectancy marked in years. Today their life expectancy is several decades thanks to regular blood transfusions and related therapies.

Cooley's anemia is one of several blood disorders that are collectively termed thalassemia, which comes from the Greek word "thalassa" which means "sea." Today, thalassemia is most concentrated among people of Mediterranean, Middle Eastern, northern African, south and southeast Asian, and Chinese descent, although it affects people in all parts of the world. Worldwide, about 100,000 children are born with thalassemia each year.

A heritable blood disorder, Cooley's anemia is characterized by defective production of hemoglobin, the oxygen-carrying protein found in red blood cells. First described in 1925 by the physician Thomas Benton Cooley, the disease is caused by a mutation in genes for β-globin proteins. Hemoglobin lacking functional β-globin is unable to carry oxygen. The closely related disorders of α-thalassemia are caused by mutations in the genes for α-globin (normal hemoglobin has two α- and two β-chains). Patients with these disorders suffer from anemia and are dependent on transfusions for life.

With anemia and transfusions come many other complications, the most important being iron accumulation in the liver, heart, and other organs. Regular pharmacological chelation is essential to reduce iron buildup. Additional complications include an enlarged spleen (splenomegaly), low bone density, depressed fertility, and increased risk of stroke or pulmonary embolism. Researchers are working to understand how these problems arise and how they can be prevented or treated.

The only proven way to cure Cooley's anemia is with hematopoietic stem cell transplantation. More than 2500 individuals have been permanently cured this way over the past 25 years, and work is forging ahead on how to expand the availability of this technique to more patients. Gene therapy has for the first time been tested as a cure for Cooley's anemia, and one patient is showing apparent benefit 28 months after the procedure.

To discuss the recent revelations and chart a route forward, the Cooley's Anemia Foundation and the New York Academy of Sciences convened a meeting of Cooley's anemia researchers and clinicians at the New York Academy of Sciences from October 21–24, 2009, for the Ninth Cooley's Anemia Symposium. The symposium addressed the advancements in research and treatment that have occurred since the Eighth Symposium was held in 2005.

The meeting highlights included:

Gene Therapy: The first patient has been treated and appears to be showing clinical improvement 28 months post-transplant.

Hematopoietic Stem Cell Transplantation: This cure is becoming more widely available as researchers explore new cell sources such as umbilical cord blood and unrelated donor bone marrow. Novel patient conditioning regimens are reducing transplant-related risks.

Fetal Hemoglobin: A number of new advances have been made toward the goal of reactivating the patient's own fetal hemoglobin (HbF). This could provide patients with hemoglobin capable of carrying oxygen, thus breaking the reliance on transfusions.

Iron Regulation: A greater understanding of the mechanisms by which the body controls iron, including factors such as hepcidin, JAK2, and TMPRSS6, may someday give clinicians tools for managing iron, reducing the need for chelation.

New Chelation Protocols: A new orally available chelator, deferasirox (DFS, Exjade), has proven efficacious at removing iron from the liver and heart. Combination chelation therapy may provide the best clinical outcome.

Iron Imaging: Magnetic Resonance Imaging (MRI) can detect liver, heart, and endocrine gland iron levels. MRI can predict cardiac dysfunction. It also provides a way to monitor chelation efficacy.

Adult Thalassemics: Prevention, early detection, and treatment could help adult β-thalassemics who suffer from reproductive difficulties, pulmonary hypertension, thrombosis, stroke, and osteoporosis.

Nutrition and Antioxidants: Antioxidant supplementation in combination with iron chelation could be more effective at reducing iron overload than chelation alone.

Backgrounder: Cooley's Anemia and Other Thalassemias

Genetic basis

Hemoglobin (adult hemoglobin, or hemoglobin A, HbA) is composed of two α-protein subunits and two β-protein subunits. All four units plus heme iron are required for carrying oxygen effectively. Two genes code for β-globin on chromosome 11. Four genes code for α-globin on chromosome 16. A heritable disease, thalassemia is passed from parents to their children.

β-thalassemia (Cooley's anemia)

Individuals with mutations in both β-globin genes have homozygous β-thalassemia, also called β-thalassemia major or Cooley's anemia. The resulting hemoglobin has two α-globins but no β-globins (β⁰), so it is unable to carry oxygen to the tissues. With no β-globin proteins to partner with, the α-globin proteins cannot fold properly, and there can also be upregulation of α-globin genes. As a result, the α-globin proteins become tangled and destroy the red blood cells (erythrocytes) in which they accumulate. The body launches an ineffectual attempt to produce more red blood cells, a process called "ineffective erythropoiesis." Another compensation strategy is extramedullary hematopoiesis, where red blood cells are made outside the bone marrow. The red blood cells are filtered in the spleen, which becomes overloaded and enlarged (splenomegaly), and often must be removed (splenectomy). Individuals must receive blood transfusions regularly, often about once a month. Unused iron builds up in the liver, heart, and endocrine organs. Regular chelation is necessary to reduce iron overload.

Complications in β-thalassemia. (Courtesy of John C. Wood, Children's Hospital of Los Angeles.)

Thalassemia trait

Individuals who inherit one mutated β-globin gene and one intact β-globin gene have β-thalassemia trait, or β-thalassemia minor. The intact β-globin gene will produce enough β-globin to compensate for the defective gene, so individuals have little or no anemia.

Thalassemia intermedia

Over 200 types of mutations can affect β-globins. Some individuals have mutations that confer mild impairments in the β-globins that don't completely obliterate their activity. These individuals are said to have thalassemia intermedia. They do not need frequent transfusions, although debate continues about how best to treat them.

α-thalassemia

Individuals with mutations in α-globin genes have α-thalassemia. This condition is usually marked by mild anemia that often goes undetected. However, if all four α-globin genes are defective or absent (known as Hemoglobin Barts), the result is a usually fatal condition called hydrops fetalis. The fetus usually dies during pregnancy or shortly after birth, and the mother may suffer complications such as high blood pressure and hemorrhaging.

Combination syndromes

Mutations in the α- and β-globin genes can co-occur with other mutations to produce complex syndromes. These include hemoglobin E and sickle β-thalassemia. Hemoglobin E/β⁰-thalassemia ranges in severity as a β-thalassemia intermedia syndrome, but over time individuals may suffer from splenomegaly, iron loading, and anemia that requires transfusion. 

Speakers:
John Porter, University College London, UK
Antonio Piga, University of Turin, IT
Renzo Galanello, University of Cagliari, IT
Paul Telfer, Barts and the London School of Medicine and Dentistry, UK
Ellis J. Neufeld, Children's Hospital Boston, US

Iron Chelators

Iron chelators are required to remove iron that builds up in β-thalassemic patients. Three chelators are currently available, desferrioxamine (DFO), deferiprone (DFP, L1, DMHP; Ferriprox, ApoPharma), and deferasirox (DFS; Exjade, Novartis). Each has slightly different properties.

One of the most exciting new developments in the past five years is the approval of a novel oral chelator, deferasirox, said John Porter of University College London. The long half-life is suitable for once a day daily dosing. Over 3000 iron-overloaded patients, including 160 pediatric patients, have been studied, allowing for a good understanding of the doses needed to manage patient iron levels. Side effects are limited to skin rash and gastrointestinal complaints that seem to diminish with time. Doses as high as 30 mg/kg/day have been given without adverse events. Serum ferritin declined and in patients with mild to moderate levels of myocardial iron, the drug resulted in significant reduction of cardiac iron. Deferasirox is especially good at removing NTBI because of its long half-life.

Deferiprone is an orally bioavailable chelator that has been used widely since the late 1990s, but which as of this date has not completed the FDA approval process. Although there have been some instances of neutropenia and agranulocytosis associated with the drug, a number of studies have indicated that deferiprone is especially effective in removing cardiac iron, said Antonio Piga of the University of Turin, when given alone and in combination with another chelator, desferrioxamine. The dose required appears to vary greatly from patient to patient, indicating that individual differences in liver detoxification enzymes may play a role in efficacy.

Both deferasirox and deferiprone have been evaluated in combination therapy with desferrioxamine, a potent chelator that must be given via subcutaneous infusion due to its short half-life in the blood. Combination chelation therapy (CCT), defined as administration of two iron chelators either concurrently (together) or sequentially (on the same day at different times or different days of the week), offers the ability to access multiple iron sequestration sites at the same time. DFP and DFO CCT can reduce cardiac and hepatic iron overload and improve cardiac function, and may reverse some iron-induced endocrine complications, reported Renzo Galanello of the University of Cagliari. DFO and DFP may work together in a shuttle effect, where DFP removes the iron from the organs and hands it off to DFO to remove it from the blood.

CCT has the potential to rapidly reduce iron loading compared with monotherapy. In a recent study of CCT in Cyprus, patients that switched from DFO to CCT were 7 times more likely to survive per year of CCT, and the survival benefit was primarily due to reduction in cardiac deaths, said Paul Telfer of Barts and the London School of Medicine and Dentistry.

So far only DFP and DFO combinations have been studied, and more studies should be done on DFO and DFS, DFP and DFS, and other combinations, said Ellis J. Neufeld of Children's Hospital Boston. In this area clinical practice has outstripped clinical trials, and patients are clamoring for clear direction as to when to use which chelators in which combinations. Treatments should be tailored to the individual patient's iron-loading situation, many researchers commented.