OBJECTIVETo investigate phenotype, cell differentiation and cytogenetic properties of bone marrow (BM) mesenchymal stem cells (MSC) separated from the myelodysplastic syndrome (MDS) patients. And to analyze cytogenetic aberration of MSC derived from MDS (MDS-MSC) and its mechanism in pathogenesis of MDS.

METHODSAdherent MSC from both myelodysplastic (n = 22) and normal (n = 7) marrow were obtained by a stromal culture procedure. Morphological features were observed by optical microscope. The cell-surface antigens were performed by flow cytometer(FCM). Adipogenic and osteogenic differentiation potential of MSC were identified under specific induction conditions. Standard cytogenetic analysis of both hematopoietic cells and MSC were performed by trypsin-Giemsa (GTG) banding. The karyotype analysis DNA content was determined by FCM to verify the results.

RESULTSThe morphology of MDS-MSC was typical slender spindle-shaped cells, MSC obtained from MDS patients had a MSC immunophenotype, lacked the expression of hematopoietic antigens-CD34, CD45 and expressed MSC markers, such as CD73, CD90, and CD105. MDS-MSC layers showed the capability to differentiate towards adipocytes, chondrocytes and osteoblasts. Cytogenetic aberrations were observed in MSC from 14 (64%) MDS patients, usually involve the loss of chromosomal material (92%), and the clonal loss (7 cases, 50%). Two cases of structural aberrations were also detected. Abnormal karyotypes in MSC were still more frequently identified in abnormal hematopoietic cells group (12 out of 13, 92% vs 3 out of 9, 33%, P < 0.05). There were not exactly the same type of chromosomal aberrations between hematopoietic cells and MSC, but different type of the aberrations in the same chromosome were involved.

CONCLUSIONMDS-MSC retains the phenotyping characteristics and differentiated function of normal MSC, but has different type of chromosomal abnormalities. A high proportion of loss of chromosomal may be a marker of chromosomal instability of MDS-MSC. Detection of abnormalities in MDS-MSC suggests enhanced genetic susceptibility of these cells in MDS. This may indicate potential involvement of MSC in the pathophysiology of MDS.