• Question: What’s the biggest breakthrough you’ve found in your research so far?

    Asked by DarrenAB to Candice on 30 Jun 2020.
    • Photo: Candice Ashmore-Harris

      Candice Ashmore-Harris answered on 30 Jun 2020: last edited 30 Jun 2020 3:29 pm

      Hi Darren, thanks for you question! I work across two very different fields – regenerative medicine and imaging sciences. Regenerative medicine looks at how you can use different therapies to regenerate or repair damaged organs or parts of organs (as there aren’t enough donors for all the people that need replacement of whole organs). My research has focused on regenerative therapies for the liver, and is looking at whether you can transplant cells into the damaged organ that either replace the lost function of the damaged cells or encourage the damaged tissue to fix itself based on signals released by the transplanted healthy cells. We call these ‘cell therapies’ and you can either use freshly isolated cells (so an organ that can be used for transplant can be digested to separate certain cells for transplant) or you can use cells grown in a petri dish in an incubator in the lab. During my PhD I grew stem cells in a dish and matured (differentiated) them to become specific kinds of liver cells called hepatocytes by feeding them specific cocktails of molecules and proteins. I was also able to make liver ‘organoids’ (basically mini livers) in dishes by mixing these immature hepatocytes with immature blood vessel and connective tissue cells. These organoids have potential as a cell therapy as well.
      The other side of my research is tracking these cell therapies in animal models using medical imaging to try to make them better for patients (e.g. to help more cells survive transplant and stay where they are needed in the body for longer or to improve their ability to repair the damage they encounter). Most of my research so far for this has focused on ‘making tools’ to track the cells and checking that the tools work. For example, with the hepatocytes differentiated from stem cells I used viruses to modify the genes in the cell to express a ‘reporter protein’ before transplanting them. This reporter protein means the cells can take in certain radioactively labelled compounds, which other cells can’t. By using a positron emission tomography scanner and image of the amount and location of radioactive decay can be taken in real-time, from this I’m able to tell where the cells are, because the decay is specific for the cells I’ve transplanted as it mostly only these cells can take up the radiotracer. Using computer software I can convert the images of the radioactive day into a 3D model representing how much decay is detected and I can combine this with x-rays to give better information on the specific location within the body.
      The ‘biggest’ breakthrough so far has probably been to show that using these reporter genes doesn’t seem to have a negative effect on the function of the cell that we’re tracking. This means the cells produce the same level of enzymes and proteins as we would normally expect, have the same shape etc. This is really important, because otherwise this tracking technique would not be a valid tool because it would alter the benefits of the therapy.