Impaired clonogenic growth of myelodysplastic bone marrow progenitors in vitro is irrelevant to their apoptotic state.
Excessive intramedullary apoptosis has been considered to account for the paradox of hypercellular marrow and refractory cytopenias in myelodysplastic syndrome (MDS). However, a causative relationship of apoptosis to the progenitor's defective clonogenic growth has not been sufficiently demonstrated. We investigated the degree of apoptosis and its contribution to ineffective hematopoiesis in MDS, by assessing the differential clonogenic capacity of purified "apoptotic" and "non-apoptotic" bone marrow progenitors in a short-term semisolid culture system. Although increased apoptosis was indeed detected in MDS bone marrow progenitors, there was no correlation between the existence of apoptosis and culture performance. Non-apoptotic as well as apoptotic CD34+ cells gave similar patterns of growth, both defective compared to normal. The ability of "apoptotic" CD34+ cells to proceed in colony formation as well as the abnormal growth of "non-apoptotic" progenitors are probably pointing towards the need to reconsider the role of apoptosis in the defective clonogenicity of MDS.
Michalopoulou
Sotiria
S
Hematology Division, Department of Internal Medicine, Patras University Medical School, Patras 26500, Greece.
Micheva
Ilina
I
Kouraklis-Symeonidis
Alexandra
A
Kakagianni
Theodora
T
Symeonidis
Argiris
A
Zoumbos
Nicholas C
NC
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017304:Annexin A5 / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism; D017209:Apoptosis; D001854:Bone Marrow Cells / Q000378:metabolism / Q000473:pathology*; D002478:Cells, Cultured; D005260:Female; D006410:Hematopoiesis; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009190:Myelodysplastic Syndromes / Q000378:metabolism / Q000473:pathology*; D013234:Stem Cells; D014410:Tumor Stem Cell Assay
D017304:Annexin A5; D018952:Antigens, CD34