ABSTRACT
Possible pathomechanisms regarding the thromboreductive effect of anagrelide (ANA)
include decrease in the megakaryocyte cell mass or life span of platelets, interference
with maturation, and stimulation of apoptosis and proliferation. Finally, a fibrogenic
effect has been reported in patients with high-risk essential thrombocythemia (ET).
Based on scrutinized evaluations, including immunohistochemistry and morphometry performed
on representative bone marrow (BM) biopsies, ANA was found to exert a significant
influence on the endoreduplicative activity of megakaryopoiesis, with an arrest of
maturation at lower ploidy stages causing a predominance of precursors. This result
confirms and greatly extends former investigations that also failed to document a
decrease in quantity or enhancement of apoptosis. Moreover, a comparative study on
the putative mutagenic capacity of hydroxyurea (HU) versus ANA treatment reveals that
both agents generate a left-shifting of megakaryocytes. However, HU creates conspicuously
expressed maturation defects consistent with dysplastic changes of megakaryopoiesis,
and therefore supports concerns about the possible leukemogenic potential of this
drug. On the other hand, in follow-up examinations of BM specimens, ANA failed to
show a stimulation of myelofibrosis in ET, provided diagnosis was established according
to the World Health Organization criteria.
KEYWORDS
Megakaryocytes - endoreduplicative capacity - apoptosis - proliferation - anagrelide
- hydroxyurea - maturation defects - fibrogenic activity
REFERENCES
- 1
Schafer A I.
Thrombocytosis.
N Engl J Med.
2004;
350
1211-1219
- 2
Tefferi A, Murphy S.
Current opinion in essential thrombocythemia: pathogenesis, diagnosis, and management.
Blood Rev.
2001;
15
121-131
- 3
Barbui T, Finazzi G.
Risk factors and prevention of vascular complications in polycythemia vera.
Semin Thromb Hemost.
1997;
23
455-461
- 4
Barbui T.
Indications for lowering platelet numbers in essential thrombocythemia.
Semin Hematol.
2003;
40
22-25
- 5
Barbui T, Finazzi G.
Treatment indications and choice of a platelet-lowering agent in essential thrombocythemia.
Curr Hematol Rep.
2003;
2
248-256
- 6
Griesshammer M, Langer C.
Pharmacotherapy of essential thrombocythaemia: economic considerations.
Expert Opin Pharmacother.
2003;
4
1499-1505
- 7
Pescatore S L, Lindley C.
Anagrelide: a novel agent for the treatment of myeloproliferative disorders.
Expert Opin Pharmacother.
2000;
1
537-546
- 8
Tefferi A, Silverstein M N, Petitt R M, Mesa R A, Solberg Jr L A.
Anagrelide as a new platelet-lowering agent in essential thrombocythemia: mechanism
of actin, efficacy, toxicity, current indications.
Semin Thromb Hemost.
1997;
23
379-383
- 9
Tefferi A, Elliott M A, Solberg Jr L A, Silverstein M N.
New drugs in essential thrombocythemia and polycythemia vera.
Blood Rev.
1997;
11
1-7
- 10
Silverstein M N, Petitt R M, Solberg Jr L A, Fleming J S, Knight R C, Schacter L P.
Anagrelide: a new drug for treating thrombocytosis.
N Engl J Med.
1988;
318
1292-1294
- 11
Balduini C L, Bertolino G, Noris P, Ascari E.
Effect of anagrelide on platelet count and function in patients with thrombocytosis
and myeloproliferative disorders.
Haematologica.
1992;
77
40-43
- 12
Mazzucconi M G, De Sanctis V, Chistolini A, Dragoni F, Mandelli F.
Therapy with anagrelide in patients affected by essential thrombocythemia: preliminary
results.
Haematologica.
1992;
77
315-317
- 13
Petrides P E, Beykirch M K, Trapp O M.
Anagrelide, a novel platelet lowering option in essential thrombocythaemia: treatment
experience in 48 patients in Germany.
Eur J Haematol.
1998;
61
71-76
- 14
Bellucci S, Legrand C, Boval B, Drouet L, Caen J.
Studies of platelet volume, chemistry and function in patients with essential thrombocythaemia
treated with anagrelide.
Br J Haematol.
1999;
104
886-892
- 15
Silverstein M N, Tefferi A.
Treatment of essential thrombocythemia with anagrelide.
Semin Hematol.
1999;
36
23-25
- 16
Laguna M S, Kornblihtt L I, Marta R F, Michiels J J, Molinas F C.
Effectiveness of anagrelide in the treatment of symptomatic patients with essential
thrombocythemia.
Clin Appl Thromb Hemost.
2000;
6
157-161
- 17
Anagrelide Study Group .
Anagrelide, a therapy for thrombocythemic states: experience in 577 patients.
Am J Med.
1992;
92
69-76
- 18
Petitt R M, Silverstein M N, Petrone M E.
Anagrelide for control of thrombocythemia in polycythemia and other myeloproliferative
disorders.
Semin Hematol.
1997;
34
51-54
- 19
Andersson B S.
Essential thrombocythemia: diagnosis and treatment, with special emphasis on the use
of anagrelide.
Hematology (Am Soc Hematol Educ Program).
2002;
7
173-177
- 20
Solberg Jr L A.
Therapeutic options for essential thrombocythemia and polycythemia vera.
Semin Oncol.
2002;
29
10-15
- 21
Storen E C, Tefferi A.
Long-term use of anagrelide in young patients with essential thrombocythemia.
Blood.
2001;
97
863-866
- 22
Brooks W G, Stanley D D, Goode J V.
Role of anagrelide in the treatment of thrombocytosis.
Ann Pharmacother.
1999;
33
1116-1118, 1121
- 23
Petrides P E.
Anagrelide: a decade of clinical experience with its use for the treatment of primary
thrombocythaemia.
Expert Opin Pharmacother.
2004;
5
1781-1798
- 24
Dingli D, Tefferi A.
A critical review of anagrelide therapy in essential thrombocythemia and related disorders.
Leuk Lymphoma.
2005;
46
641-650
- 25
Liozon E, Brigaudeau C, Trimoreau F et al..
Is treatment with hydroxyurea leukemogenic in patients with essential thrombocythemia?
An analysis of three new cases of leukaemic transformation and review of the literature.
Hematol Cell Ther.
1997;
39
11-18
- 26
Sterkers Y, Preudhomme C, Lai J L et al..
Acute myeloid leukemia and myelodysplastic syndromes following essential thrombocythemia
treated with hydroxyurea: high proportion of cases with 17p deletion.
Blood.
1998;
91
616-622
- 27
Finazzi G, Barbui T.
Treatment of essential thrombocythemia with special emphasis on leukemogenic risk.
Ann Hematol.
1999;
78
389-392
- 28
Randi M L, Fabris F, Girolami A.
Leukemia and myelodysplasia effect of multiple cytotoxic therapy in essential thrombocythemia.
Leuk Lymphoma.
2000;
37
379-385
- 29
Barbui T.
The leukemia controversy in myeloproliferative disorders: is it a natural progression
of disease, a secondary sequela of therapy, or a combination of both?.
Semin Hematol.
2004;
41
15-17
- 30
Finazzi G, Ruggeri M, Rodeghiero F, Barbui T.
Second malignancies in patients with essential thrombocythaemia treated with busulphan
and hydroxyurea: long-term follow-up of a randomized clinical trial.
Br J Haematol.
2000;
110
577-583
- 31
Fruchtman S M.
Treatment paradigms in the management of myeloproliferative disorders.
Semin Hematol.
2004;
41
18-22
- 32
Furgerson J L, Vukelja S J, Baker W J, O'Rourke T J.
Acute myeloid leukemia evolving from essential thrombocythemia in two patients treated
with hydroxyurea.
Am J Hematol.
1996;
51
137-140
- 33
Higuchi T, Okada S, Mori H, Niikura H, Omine M, Terada H.
Leukemic transformation of polycythemia vera and essential thrombocythemia possibly
associated with an alkylating agent.
Cancer.
1995;
75
471-477
- 34
Löfvenberg E, Nordenson I, Wahlin A.
Cytogenetic abnormalities and leukemic transformation in hydroxyurea-treated patients
with Philadelphia chromosome negative chronic myeloproliferative disease.
Cancer Genet Cytogenet.
1990;
49
57-67
- 35
Nielsen I, Hasselbalch H C.
Acute leukemia and myelodysplasia in patients with a Philadelphia chromosome negative
chronic myeloproliferative disorder treated with hydroxyurea alone or with hydroxyurea
after busulphan.
Am J Hematol.
2003;
74
26-31
- 36
Weinfeld A, Swolin B, Westin J.
Acute leukaemia after hydroxyurea therapy in polycythaemia vera and allied disorders:
prospective study of efficacy and leukaemogenicity with therapeutic implications.
Eur J Haematol.
1994;
52
134-139
- 37
Abe Andes W, Noveck R J, Fleming J S.
Inhibition of platelet production induced by an antiplatelet drug, anagrelide, in
normal volunteers.
Thromb Haemost.
1984;
52
325-328
- 38
Mazur E M, Rosmarin A G, Sohl P A, Newton J L, Narendran A.
Analysis of the mechanism of anagrelide-induced thrombocytopenia in humans.
Blood.
1992;
79
1931-1937
- 39
Solberg Jr L A, Tefferi A, Oles K J et al..
The effects of anagrelide on human megakaryocytopoiesis.
Br J Haematol.
1997;
99
174-180
- 40
Le Bousse-Kerdiles M C, Martyre M C.
Dual implication of fibrogenic cytokines in the pathogenesis of fibrosis and myeloproliferation
in myeloid metaplasia with myelofibrosis.
Ann Hematol.
1999;
78
437-444
- 41
Martyre M C.
Critical review of pathogenetic mechanisms in myelofibrosis with myeloid metaplasia.
Curr Hematol Rep.
2003;
2
257-263
- 42
Schmitt A, Drouin A, Masse J M, Guichard J, Shagraoui H, Cramer E M.
Polymorphonuclear neutrophil and megakaryocyte mutual involvement in myelofibrosis
pathogenesis.
Leuk Lymphoma.
2002;
43
719-724
- 43
Harrison C N, Campbell P J, Buck G et al..
Hydroxyurea compared with anagrelide in high-risk essential thrombocythemia.
N Engl J Med.
2005;
353
33-45
- 44
Yoon S Y, Li C Y, Mesa R A, Tefferi A.
Bone marrow effects of anagrelide therapy in patients with myelofibrosis with myeloid
metaplasia.
Br J Haematol.
1999;
106
682-688
- 45
Tomer A.
Effects of anagrelide on in vivo megakaryocyte proliferation and maturation in essential
thrombocythemia.
Blood.
2002;
99
1602-1609
- 46
Tomer A, Friese P, Conklin R et al..
Flow cytometric analysis of megakaryocytes from patients with abnormal platelet counts.
Blood.
1989;
74
594-601
- 47
Gatter K C, Cordell J L, Turley H et al..
The immunohistological detection of platelets, megakaryocytes and thrombi in routinely
processed specimens.
Histopathology.
1988;
13
257-267
- 48
Thiele J, Wagner S, Dienemann D, Wienhold S, Fischer R, Stein H.
Megakaryocyte precursors (promegakaryoblasts and megakaryoblasts) in the normal human
bone marrow. An immunohistochemical and morphometric study on routinely processed
trephine biopsies.
Anal Quant Cytol Histol.
1990;
12
285-289
- 49
Thiele J, Wagner S, Degel C et al..
Megakaryocyte precursors (pro- and megakaryoblasts) in bone marrow tissue from patients
with reactive thrombocytosis, polycythemia vera and primary (essential) thrombocythemia.
An immunomorphometric study.
Virchows Arch B Cell Pathol Incl Mol Pathol.
1990;
58
295-302
- 50
Ishibashi T, Ruggeri Z M, Harker L A, Burstein S A.
Separation of human megakaryocytes by state of differentiation on continuous gradients
of Percoll: size and ploidy analysis of cells identified by monoclonal antibody to
glycoprotein IIb/IIIa.
Blood.
1986;
67
1286-1292
- 51
Levene R B, Williams N T, Lamaziere J M, Rabellino E M.
Human megakaryocytes. IV. Growth and characterization of clonable megakaryocyte progenitors
in agar.
Exp Hematol.
1987;
15
181-189
- 52
Levine R F, Hazzard K C, Lamberg J D.
The significance of megakaryocyte size.
Blood.
1982;
60
1122-1131
- 53
Williams N, Levine R F.
The origin, development and regulation of megakaryocytes.
Br J Haematol.
1982;
52
173-180
- 54
Queisser U, Queisser W, Spiertz B.
Polyploidization of megakaryocytes in normal humans, in patients with idiopathic thrombocytopenia
and with pernicious anaemia.
Br J Haematol.
1971;
20
489-501
- 55
Thiele J, Kvasnicka H M, Fuchs N, Brunnbauer K, Volkwein N, Schmitt-Graeff A.
Anagrelide-induced bone marrow changes during therapy of chronic myeloproliferative
disorders with thrombocytosis. An immunohistochemical and morphometric study of sequential
trephine biopsies.
Haematologica.
2003;
88
1130-1138
- 56
Hall P A, Levison D A.
Review: assessment of cell proliferation in histological material.
J Clin Pathol.
1990;
43
184-192
- 57
Thiele J, Kvasnicka H M, Ollig S, Schmitt-Graeff A.
Anagrelide does not exert a myelodysplastic effect on megakaryopoiesis-a comparative
immunohistochemical and morphometric study with hydroxyurea.
Histol Histopathol.
2005;
20
1071-1076
- 58
Tricot G, De Wolf-Peeters C, Hendrickx B, Verwilghen R L.
Bone marrow histology in myelodysplastic syndromes. I. Histological findings in myelodysplastic
syndromes and comparison with bone marrow smears.
Br J Haematol.
1984;
57
423-430
- 59
Delacretaz F, Schmidt P M, Piguet D, Bachmann F, Costa J.
Histopathology of myelodysplastic syndromes. The FAB classification (proposals) applied
to bone marrow biopsy.
Am J Clin Pathol.
1987;
87
180-186
- 60
Fox S B, Lorenzen J, Heryet A, Jones M, Gatter K C, Mason D Y.
Megakaryocytes in myelodysplasia: an immunohistochemical study on bone marrow trephines.
Histopathology.
1990;
17
69-74
- 61
Rios A, Canizo M C, Sanz M A et al..
Bone marrow biopsy in myelodysplastic syndromes: morphological characteristics and
contribution to the study of prognostic factors.
Br J Haematol.
1990;
75
26-33
- 62 Thiele J, Imbert M, Pierre R.
Chronic idiopathic myelofibrosis. In: Jaffe ES, Harris NL, Stein H, Vardiman JW WHO Classification of Tumours: Tumours
of Haematopoietic and Lymphoid Tissue. Lyon, France; IARC Press 2001: 35-38
- 63
Thiele J, Wagner S, Weuste R et al..
An immunomorphometric study on megakaryocyte precursor cells in bone marrow tissue
from patients with chronic myeloid leukemia (CML).
Eur J Haematol.
1990;
44
63-70
- 64
Thiele J, Kvasnicka H M, Schmitt-Graeff A, Diehl V.
Bone marrow histopathology following cytoreductive therapy in chronic idiopathic myelofibrosis.
Histopathology.
2003;
43
470-479
- 65
Harrison C N.
Essential thrombocythemia: challenges and evidence-based management.
Br J Haematol.
2005;
130
153-165
- 66
Murphy S.
Diagnostic criteria and prognosis in polycythemia vera and essential thrombocythemia.
Semin Hematol.
1999;
36
9-13
- 67
Murphy S, Peterson P, Iland H, Laszlo J.
Experience of the Polycythemia Vera Study Group with essential thrombocythemia: a
final report on diagnostic criteria, survival, and leukemic transition by treatment.
Semin Hematol.
1997;
34
29-39
- 68
Pearson T C.
Diagnosis and classification of erythrocytoses and thrombocytoses.
Baillieres Clin Haematol.
1998;
11
695-720
- 69
Florena A M, Tripodo C, Iannitto E, Porcasi R, Ingrao S, Franco V.
Value of bone marrow biopsy in the diagnosis of essential thrombocythemia.
Haematologica.
2004;
89
911-919
- 70
Thiele J, Kvasnicka H M, Zankovich R, Diehl V.
Relevance of bone marrow features in the differential diagnosis between essential
thrombocythemia and early stage idiopathic myelofibrosis.
Haematologica.
2000;
85
1126-1134
- 71
Thiele J, Kvasnicka H M.
Chronic myeloproliferative disorders with thrombocythemia: a comparative study of
two classification systems (PVSG, WHO) on 839 patients.
Ann Hematol.
2003;
82
148-152
- 72 Imbert M, Pierre R, Thiele J, Vardiman J W, Brunning R D, Flandrin G.
Essential thrombocythaemia. In: Jaffe ES, Harris NL, Stein H, Vardiman JW WHO Classification of Tumours: Tumours
of Haematopoietic and Lymphoid Tissues. Lyon, France; IARC Press 2001: 39-41
- 73
Buhr T, Busche G, Choritz H, Langer F, Kreipe H.
Evolution of myelofibrosis in chronic idiopathic myelofibrosis as evidenced in sequential
bone marrow biopsy specimens.
Am J Clin Pathol.
2003;
119
152-158
- 74
Georgii A, Buesche G, Kreft A.
The histopathology of chronic myeloproliferative diseases.
Baillieres Clin Haematol.
1998;
11
721-749
- 75
Thiele J, Kvasnicka H M, Schmitt-Graeff A, Diehl V.
Dynamics of fibrosis in chronic idiopathic (primary) myelofibrosis during therapy:
a follow-up study on 309 patients.
Leuk Lymphoma.
2003;
44
949-953
- 76
Thiele J, Kvasnicka H M.
Prefibrotic chronic idiopathic myelofibrosis-a diagnostic enigma?.
Acta Haematol.
2004;
111
155-159
- 77
Kreft A, Buche G, Ghalibafian M, Buhr T, Fischer T, Kirkpatrick C J.
The incidence of myelofibrosis in essential thrombocythaemia, polycythaemia vera and
chronic idiopathic myelofibrosis: a retrospective evaluation of sequential bone marrow
biopsies.
Acta Haematol.
2005;
113
137-143
- 78
Thiele J, Kvasnicka H M, Dietrich H et al..
Dynamics of bone marrow changes in patients with chronic idiopathic myelofibrosis
following allogeneic stem cell transplantation.
Histol Histopathol.
2005;
20
879-889
- 79
Thiele J, Kvasnicka H M.
Clinicopathological criteria for differential diagnosis of thrombocythemias in various
MPDs.
Semin Thromb Hemost.
2006;
32
219-230
- 80
Kvasnicka H M, Thiele J.
The impact of clinicopathological studies in staging and survival in ET, PV and IMF.
Semin Thromb Hemost.
2006;
32
362-371
- 81
Thiele J, Kvasnicka H M, Orazi A.
Bone marrow histopathology in myeloproliferative disorders-current diagnostic approach.
Semin Hematol.
2005;
42
184-195
Juergen ThieleM.D.
Institute for Pathology, University of Cologne, Joseph-Stelzmann-Str. 9
D-50924 Cologne, Germany
eMail: j.thiele@uni-koeln.de