Polycythemia Vera, Cytogenetic And Bone Marrow Mesenchymal Stem Cell Features

PartⅠCytogenetic Analysis in Polycythemia VeraObjective To evaluate the incidence of chromosomal abnormalities inpolycythemia vera (PV) accurately and investigate the value offluorescence in situ hybridization (FISH) technique in the detection oftrisomies 8 (+8) and 9 (+9).Methods Conventional cytogenetics (CC) was carried out to detectkaryotype and interphase FISH was used to detect +8 and +9 in 50 newlydiagnosed PV and 8 normal individuals.Results Among 50 cases, 3 patients had chromosome abnormalitiesby CC technique, including one each for +8, -Y andinv(11)(p15;q22),+?,der(19). FISH detected two cases of +8, including theconfirmed one by CC, and one case of+9 neglected by CC.Conclusion The incidence of chromosomal abnormalities in PV wasrare, and the abnormalities of +8 and +9 found in this study was relativelylower than reported, due to the limited number of samples. InterphaseFISH, as an important complement to CC, was a useful method for thedetection of +8 and +9. PartⅡIsolation and culture of bone marrow mesenchymalstem cells in polycythemia vera and their functionalcharacteristicsObjective To isolate and culture bone marrow mesenchymal stem cell(MSCs) from polycythemia vera (PV) patients and examine theirfunctional characteristics.Methods Bone marrow was extracted from the anterior superior iliacspines of 9 patients with PV and 6 normal individuals. MSCs were isolatedand cultured by density gradient centrifugation combined with adherenceculture. The cultured cells in the third, sixth and tenth passage wereassessed. The morphology of the cells was observed by Giemsa stainingand the growth curve of the cells was plotted. The ultrastructure of MSCswas observed with electron microscopy. The cell cycle andimmunophenotype of the expanded MSCs were detected by flowcytometry (FCM). Different agents were used to induce MSCs todifferentiate into osteocyte and adipocyte. Von Kossa staining and oil-redstaining were used to examine the ability of differentiation. Conventionalcytogenetics (CC) was carried out to detect karyotype. Alleles specificpolymerase chain reaction (AS-PCR) was used to detect JAK2V617Fmutation. Results PV and normal individuals derived MSCs displayed afibroblast-like morphology adhering to the culture plate and the doublingtime of expand MSCs was about 43h. More than 90% cells were at G0/G1,and less than 10% cells at S phase of cell cycle. FCM can also show thatthe cells expressed several MSCs-related antigens such as CD73 and CD90,while CD34, CD45, CD133 and HLA-DR were negative. Under suitableconditions, these MSCs could differemiate into osteocytes and adipocytes.PV and normal individuals derived MSCs showed normal karyotype. AndJAK2V617F mutation was negative.Conclusion PV derived MSCs can proliferate and differentiate intodifferent type of cells in vitro. They are similar to normal MSCs inphenotype, morphology and multi-differentiation capacity.