School of Medicine

Trophoblast differentiation

Trophoblasts are cells that are only found in the placenta. There are a number of different types of trophoblasts each of which perform different essential functions during pregnancy. It was thought that all of the different types of trophoblasts arise from a single pool of precursor cells called villous cytotrophoblasts which are effectively trophoblast stem cells. Based on differential survival times in explant cultures we have found evidence that there are in fact two separate types of villous cytotrophoblasts (James et al. 2005), and are developing methods to isolate and characterise one of these which we have called extravillous trophoblast progenitors (EVTP). EVTPs are characterised by their unique location adjacent to trophoblast columns and expression of intergrin avb5. These studies are important for researchers studying diseases of pregnancy that are caused by improper trophoblast function, and who need to study the correct population of precursor cells. Our studies are also focusing on factors that control the differentiation of trophoblast progenitor cells including the level of oxygen that the cells are exposed to.


Photomicrograph of cultured EVTPs stained with an anti avb5 antibody (From James et al. 2007)



Current investigations include:

  1. Do particular extracellular matrix proteins promote EVTP growth in vitro?
  2. What markers allow separation of EVTP from other trophoblasts?
  3. Are EVTPs present in placentae of all gestational ages?

Funding for this work was provided by:

  • The The Evelyn Bond Trust (ADHB)
  • The New Zealand Lotteries Board (Health)
  • The University of Auckland Staff Research Fund
  • The Auckland Medical Aid Trust.