ABSTRACT Introduction: Culturing bone marrow mesenchymal stem cells (BM-MSCs) is a key point in different fields of research, including tissue engineering and regenerative medicine and studies of the bone marrow microenvironment. However, isolating and expanding murine BM-MSCs in vitro has challenged researchers due to the low purity and yield of obtained cells. In this study, we aimed to evaluate five different protocols to culture murine BM-MSCs in vitro. Methods: All protocols were based on the adhesion capacity of BM-MSCs to the tissue culture plastic surface and varied in the types of plate, culture media, serum, additional supplementation and initial cell density. Flow cytometry analysis was used to investigate lineage purity after expansion. Results: The expression of CD45 and CD11b was detected in the cultures generated according to all protocols, indicating low purity with the presence of hematopoietic cells and macrophages. The cellular growth rate and morphology varied between the cultures performed according to each protocol. Cells cultured according to protocol 5 (8 × 107cells/plate, Roswell Park Memorial Institute (RPMI) culture medium during first passage and then Iscove’s Modified Delbecco’s Medium (IMDM) culture medium, both supplemented with 9% fetal bovine serum, 9% horse serum, 12μM L-glutamine) presented the best performance, with a satisfactory growth rate and spindle-shape morphology. Conclusion: Our results point out that the purity and satisfactory growth rate of murine BM-MSC cultures are not easily achieved and additional approaches must be tested for a proper cell expansion.

OBJECTIVE: The aim of this study was to evaluate the expression of protein tyrosine kinase 2 and protein tyrosine phosphatase non-receptor type 11, which respectively encode focal adhesion kinase protein and src homology 2 domain-containing protein-tyrosine phosphatase 2, in hematopoietic cells from patients with myelodysplastic syndromes. METHODS: Protein tyrosine kinase 2 and tyrosine phosphatase non-receptor type 11 expressions were analyzed by quantitative polymerase chain reaction in bone marrow cells from patients with myelodysplastic syndromes and healthy donors. RESULTS: Protein tyrosine kinase 2 and tyrosine phosphatase non-receptor type 11 expressions did not significantly differ between normal cells and myelodysplastic cells. CONCLUSIONS: Our data suggest that despite the relevance of focal adhesion kinase and src homology 2 domain-containing protein-tyrosine phosphatase 2 in hematopoietic disorders, their mRNA expression do not significantly differ between total bone marrow cells from patients with myelodysplastic syndromes and healthy donors.

INTRODUCTION: Myelodysplastic syndromes encompass a heterogeneous group of clonal hematopoietic stem cell disorders characterized by ineffective hematopoiesis, refractory cytopenia and a tendency to progress toward acute myeloid leukemia. The accumulation of genetic alterations is closely associated with the progression of myelodysplastic syndromes toward acute myeloid leukemia. OBJECTIVE: To investigate the presence of mutations in the points most frequent for mutations (hotspot mutations) in phosphatidylinositol-3-kinase (PI3K), Janus kinase 2 (JAK2), FMS-like tyrosine kinase 3 (FLT3) and nucleophosmin (NPM1), which are involved in leukemia and other cancers, in a population of Brazilian MDS patients. METHODS: Fifty-one myelodysplastic syndromes patients were included in the study. According to French-American-British classification, the patients were distributed as follows: 31 with refractory anemia, 8 with refractory anemia with ringed sideroblasts, 7 with refractory anemia with excess blasts, 3 with refractory anemia with excess blasts in transformation and 2 with chronic myelomonocytic leukemia. Bone marrow samples were obtained and screened for the presence of hotspot mutations using analysis based on amplification with the polymerase chain reaction, sequencing, fragment size polymorphisms or restriction enzyme digestion. All patients were screened for mutations at the time of diagnosis, and 5 patients were also screened at the time of disease progression. RESULTS: In the genes studied, no mutations were detected in the patients at the time of diagnosis. One patient with chronic myelomonocytic leukemia was heterozygous for a Janus kinase 2 mutation after disease progression. CONCLUSIONS: These results show that hotspot mutations in the PI3K, JAK2, FLT3 and NPM1 genes are not common in MDS patients; nevertheless, JAK2 mutations may be present in myelodysplasia during disease progression.