Análise da hematopoese em amostras de medula óssea nas fases pré e pós-mobilização para transplante autólogo de célulastronco hematopoéticas periféricas

• Ano de defesa: 2009
• Autor(a) principal: Schimieguel, Dulce Marta [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Hematopoese; Transplante de medula óssea; Estroma; Doenças onco-hematológicas; Criopreservação; Antígenos CD34
• Link de acesso: http://repositorio.unifesp.br/handle/11600/8907

Autologous hematopoietic stem cell transplantation (auto-HSCT) has proved efficient to treat hematopoietic malignancies such as lymphomas, leukemia and multiple myeloma. Stem cells can be obtained directly from bone marrow or be recruited to enter in the blood stream in response to chemotherapy and hematopoietic growth factors. However, some patients fail to show adequate yield of mobilized HSCs lowering the chances for a successful auto-HSCT. For definitive hematopoiesis to occur, HSCs must interact with a suitable microenvironment, including stromal cells, extracellular matrix and soluble factors. A large number of groups have been trying to elucidate the mechanisms related to mobilization, structural and functionality of marrow stroma and HSC were done to elucidate possible damage caused on marrow microenvironment and their correlation with the short and long time hematological recovery. In this study, it was evaluated proliferate potential, capacity of hematopoiesis support and the cryopreservation effects in bone marrow samples from patients with hematological malignancies submitted to auto-HSC. Were evaluated 22 patients diagnosed with hematological malignancies, aged 16 to 60 (37,2 average) years, including 5 non-Hodgkin’s lymphoma (NHL) , 6 Hodgkin’s disease (HD), 4 multiple myeloma (MM), 5 acute myeloid leukemia (AML), 1 acute lymphoblastic leukemia (ALL) and 1 chronic lymphocytic leukemia (CLL). Ten allogeneic bone marrow donors were the control group with 26 to 45 years old. Were used long-term bone marrow cultures, clonogenical assays and bone marrow histopathology analysis at pre and post mobilization, with the purpose to observe if chemotherapy with growth factor will cause some damage to the hematopoietic stem cells or marrow stroma. It was observed stromal layer formation decreased at control samples after mobilization (p =0, 03), suggesting that normal bone marrow was more affected by G-CSF effect , or hematopoietic progenitor cells from bone marrow migrate expressively for the whole blood. Patients’ samples showed lower stromal layer formation in the control group, showing marrow microenvironment damage caused by previous chemotherapy or disease. It was not detected functional differences in patients’ samples during mobilization, no relation with capacity of stroma formation during the citotoxic therapy used in mobilization. Fibrosis, infiltration and cell decrease in bone marrow contribute to reduce the stromal layer formation capacity, suggesting that the main damages are related to marrow stroma. About the clonogenical assays only the obtained stromal layers by post-mobilization patients and CD 34+ co-cultivate cells, showing proliferative activity in these assays, with exception of the autologous CD 34+ co-cultivate control group cells. Related to cryopreservation process, it was not observed difference between pre and post phases at control and patients’ samples, which suggest that this procedure not affect marrow stroma functionality. However, the control samples showed significant decrease in stromal layer formation at the post-mobilization phase in relation to the patients’ sample, mainly in fresh samples, can suggest that the situation of marrow stroma patient with hematological malignancies before the mobilization can show one effective protection to cryopreserved agents. This finding suggests that have sick stromas that make it less susceptible to mobilization and cryopreservation process.