Congenital diseases such as blood disorders are responsible for over a third of all pediatric hospital admissions. In utero transplantation (IUT) could cure affected fetuses but so far in humans, successful IUT has been limited to fetuses with severe immunologic defects, due to the maternal immune system and a functionally developed fetal immune system. I hypothesised that using autologous fetal cells could overcome the barriers to engraftment. Previous studies show that autologous haematopoietic progenitors can be easily derived from amniotic fluid (AF), and they can engraft long term into fetal sheep. In normal mice, I demonstrated that IUT of mouse AFSC results in successful haematopoietic engraftment in immune-competent mice. Congenic AFSCs appear to have a significant advantage over allogenic AFSCs. This was seen both by their end haematopoietic potential and the immune response of the host.
Expansion of haematopoietic stem cells (HSC) has been a complicated and demanding process. To achieve adequate numbers for autologous stem cells for IUT, HSCs need to be expanded efficiently. I expanded and compared AFSCs, fetal liver stem cells and bone marrow stem cells. Culturing and expanding fetal and adult stem cells in embryonic stem cell conditions maintained their haematopoietic potential.
Using a humanised mouse model of thalassaemia, in which heterozygous animals are affected by anaemia, splenomegaly and extramedullary haematopoiesis, I explored whether in utero gene therapy (IUGT) to the fetal HSC compartment using a vector carrying the corrected beta-globin gene might cure the disease before birth. IUGT resulted in phenotypic normalisation with increased levels of beta-globin and associated downregulation of gamma-globin, consistent with a switch from fetal to adult human haemoglobin, confirming successful prenatal correction of the genetic defect.
|Advisor:||David, Anna L. M., De Coppi, Paolo|
|Commitee:||Linch, David, O’Donoghue, Keelin|
|School:||University of London, University College London (United Kingdom)|
|Source:||DAI-B 82/1(E), Dissertation Abstracts International|
|Subjects:||Medicine, Cellular biology|
|Keywords:||Amniotic fluid stem cells, Hematopoietic stem cells, In utero gene therapy, In utero stem cell Transplantation, Prenatal therapy, Thalassemia|
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