Advisor(s)
Abstract(s)
O sangue da placenta contém células estaminais hematopoéticas capazes de
reconstituir a hematopoiese a longo prazo, quando transplantadas após condicionamento
mieloablativo. Alguns estudos têm demonstrado, que a qualidade das unidades de
sangue do cordão umbilical pode ser influenciada por muitos factores obstétricos e pela
experiência de quem realiza a colheita. A contagem de células CD34+, o número total de
células nucleadas e o volume de sangue do cordão umbilical são variáveis determinantes
como critérios de aceitação para o banco de células do cordão umbilical.
O objectivo desde trabalho é avaliar a influência dos factores obstétricos e do
volume inicial de sangue do cordão umbilical na contagem de células CD34+.
Neste estudo foram utilizados dados relativos a 179 amostras de sangue do
cordão umbilical criopreservadas no LusoCord - Centro de Histocompatibilidade do
Norte entre Abril e Outubro de 2010. A colheita do sangue do cordão umbilical
realizou-se por dois métodos: in útero ou ex útero. O processamento destas amostras foi
constituído: pela verificação do volume colhido, pela contagem de leucócitos e de
células nucleadas totais (TNC), pela redução de volume antes da criopreservação, pela
contagem de células CD34+ por citometria de fluxo seguindo o protocolo ISHAGE e
pela determinação da viabilidade, recorrendo-se ao marcador de ácidos nucleicos 7-
amino-actinomicina D (7-AAD).
O valor de TNC foi superior no parto vaginal. Existe correlação estatisticamente
significativa entre o número de células CD34+ totais e o volume inicial. Encontramos
correlação estatisticamente significativa entre o volume inicial da unidade e entre o
TNC final. Verificou-se ainda, correlação entre o número de células CD34+ totais e a
idade materna. Verificou-se correlação estatisticamente significativa entre o peso dos
bebés e o volume inicial.
Pode concluir-se que os factores obstétricos e o volume inicial interferem com a
contagem de células CD34+. Um volume maior inicial está associado a um maior TNC e
maior número de células CD34+. A contagem de células CD34+ é superior em mães
mais jovens. O sangue do cordão umbilical de bebés mais pesados resultou num volume
inicial superior.
Placenta´s blood contains hematopoietic stem cells capable of reconstituting long-term hematopoiesis when transplanted after myeloablative conditioning. Some studies have demonstrated that the quality of the cord blood units can be influenced by many obstetric factors and by those who make the harvest. The CD34+ cell count, total number of nucleated cells and cord blood´s volume are determining variables as acceptance criteria for bank of umbilical cord cells. The aim of this work is to evaluate the influence of obstetrics factors and the initial cord blood´s volume in CD34+ cell count. This study used data from 179 samples of umbilical cord blood cryopreserved in LusoCord - North Histocompatibility Centre between April and October 2010. The harvest of umbilical cord blood was performed by two methods: in utero or ex utero. The processing of these samples was constituted: by monitoring the gathered volume, WBC count and total nucleated cell (TNC) count, volume reduction before cryopreservation, CD34+ cell count by flow cytometry following the ISHAGE protocol and the measurement of the viability resorting to the nucleic acid marker 7-aminoactinomycin D. We found a significant statistically correlation between the initial volume of the unit and between the final TNC value. There was also a correlation between the total number of CD34+ cells and maternal age. There was a significant statistically correlation between the weight of the babies and the initial volume. It can be concluded that obstetric factors and initial volume interfere with CD34+ cells count. A higher initial volume is associated with a greater TNC and greater number of CD34+ cells. CD34+ cell count is higher in younger mothers. The umbilical cord blood of heavier infants resulted in a higher initial volume.
Placenta´s blood contains hematopoietic stem cells capable of reconstituting long-term hematopoiesis when transplanted after myeloablative conditioning. Some studies have demonstrated that the quality of the cord blood units can be influenced by many obstetric factors and by those who make the harvest. The CD34+ cell count, total number of nucleated cells and cord blood´s volume are determining variables as acceptance criteria for bank of umbilical cord cells. The aim of this work is to evaluate the influence of obstetrics factors and the initial cord blood´s volume in CD34+ cell count. This study used data from 179 samples of umbilical cord blood cryopreserved in LusoCord - North Histocompatibility Centre between April and October 2010. The harvest of umbilical cord blood was performed by two methods: in utero or ex utero. The processing of these samples was constituted: by monitoring the gathered volume, WBC count and total nucleated cell (TNC) count, volume reduction before cryopreservation, CD34+ cell count by flow cytometry following the ISHAGE protocol and the measurement of the viability resorting to the nucleic acid marker 7-aminoactinomycin D. We found a significant statistically correlation between the initial volume of the unit and between the final TNC value. There was also a correlation between the total number of CD34+ cells and maternal age. There was a significant statistically correlation between the weight of the babies and the initial volume. It can be concluded that obstetric factors and initial volume interfere with CD34+ cells count. A higher initial volume is associated with a greater TNC and greater number of CD34+ cells. CD34+ cell count is higher in younger mothers. The umbilical cord blood of heavier infants resulted in a higher initial volume.