Stephen Marchant has worked in biotechnology in the fields of immunology, molecular imaging and stem cell research in both academia and industry.
A born entrepreneur, in 2013 he started his own business, MediLumine, which specializes in developing contrast agents for research using small animal imaging. An expert in his field, he works closely with numerous international laboratories and research centers specializing in research on cancer and other human diseases.
Here is summary of an interview with Stephen on this fascinating field.
What is a contrast agent?
It’s a substance that’s used to enhance the contrast of soft tissue structures for certain medical imaging modalities such as computed tomography (CT). Without a contrast agent, for example an x-ray imaging contrast agent, CT scans of the the human body only shows the skeleton and it’s virtually impossible to see all of the organs (commonly known as soft tissues), such as the liver, spleen or heart and any potential cancers affecting them.
What progress has there been to date?
To date, imaging contrast agents are available on the market for human beings. These products are safe and are excreted rapidly within minutes after injection. However, because they are excreted so quickly, it’s not possible to take advantage of high resolution of CT and see organs and cancerous tumours in high resolution. To take advantage of this high resolution of CT imaging, contrast agents capable of penetrating the actual cell must be used in conjuction with imaging hardware which enables higher resolution scanning such as a micro-computed tomographer used in research.
In humans, using this high resolution imaging methodology to detect cancer is still experimental and medical professionals use magnetic resonance imaging (MRI) and nuclear medicine instead.
This explains the extensive research into both imaging equipment (such as spectral CT imaging or dual-energy CT imaging) and contrast agents which are non-toxic and capable of getting inside cells.
It’s a known fact that the timing of cancer detection is critical and the earlier the detection, the greater the chances of treatment and recovery. Improved resolution in future equipment could help detect cancer in its very early stages and help to prevent it.
Lastly, it’s important to note that contrast agents must be absolutely safe and quickly excreted from the body. A contrast agent penetrating cells and staying in body for a few hours instead of a few minutes could expose the patient to two major problems; a high dose of radiation (for extended scans) and a high risk of toxicity. This is why research is being conducted globally to develop a contrast agent capable of penetrating cells (such as cancer cells) and, at the same time, design a high resolutng modality that does not does not expose patients to high doses of radiation.
How are these methods and products more ethical even though they are tested on mice?
The number of animals used in research with micro-CT contrast agents is significantly reduced. Small animal micro-CT imaging with contrast agents have enabled ways of obtaining data at different time points with imaging instead of animal sacrifice thus reducing size of examined animal cohorts.
How is MediLumine involved in this research?
Since its creation, MediLumine has been focussing on developing medical imaging contrast agents for small animal imaging, and, more specifically, more specifically angiography (vascular imaging) and liver tumor imaging agents. Major research laboratories are currently using products developed by MediLumine to detect cancer in laboratory mice or measure the effectiveness of a therapeutic intervention. The products’ strength resides in their ability to penetrate the organism’s cells while being excreted within 72 hours. The slow clearance time enables high resolution micro-CT scanning. We are also working on new theranostic concepts (or diapeutics), that is, combining delivery of imaging agents and therapeutic compounds which allows for assessing the effectiveness of a drug during the course of multiple imaging sessions.