Technologies such as the positron emission tomography (PET) and the glucose metabolism probe, fluorodeoxyglucose (FDG) have been around for a while in the oncology field as they are beneficial in detecting solid tumours.

However, Duke-NUS Medical School (Duke-NUS) and Singapore General Hospital (SGH) have partnered up to combine these tools in a completely different avenue – in infectious diseases research.

The use of PET-FDG to detect inflammation

With this combination, the team has come up with a non-invasive and novel way of tracking dengue infections in real-time. It aims to also monitor the efficacy of new therapeutic compounds to directly target major tissues affected in dengue pathogenesis.

The PET technology is able to locate and visualise cellular glucose uptake in the body; comparable to a radar detecting ships in the sea. On the other hand, FDG serves as a radioactive type of glucose. When injected into mice, the cells absorb FDG similar to normal glucose is and the process can be visualised with PET.

Studies have shown that the small and large intestines of mice tend to get inflamed in dengue infections. Due to this, the uptake of glucose and FDG in cells increases. Thus, the research team decided to utilise PET-FDG to detect inflammation as an indicator of dengue infection in mice.

Duke-NUS Assistant Professor Ann-Marie Chacko, the lead author of the study and head of the Duke-NUS for Translational and Molecular Imaging (LTMI) expressed that “to our knowledge, this is the very first time PET has been systematically evaluated in the field of acute viral infectious diseases. We are excited to be able to repurpose this non-invasive technology, and generate such robust images of live dengue infection in the body.”

Positive outcome could prove significant to humans

Results from this study found increased inflammation in the spleen, small intestines and large intestines of mice infected with dengue. Once antivirals were administered, the inflammation subsided. With the tracking of glucose uptake, progression and severity of dengue in mice could be predicted aside from evaluating the efficacy of treatments.

“Being able to visualise dengue infection in the body potentially transforms how the effectiveness of new dengue therapeutics is assessed. We look forward to collaborating with academic and industry partners who are looking to validate their new dengue therapeutics using this novel approach,” said Professor Subhash Vasudevan, senior author of the publication and a member of the Emerging Infectious Diseases Programme at Duke-NUS.

Dr Jenny Low who is a clinician on the research team and a Senior Consultant with the Department of Infectious Diseases at SGH stated, “Traditionally, in research, the amount of virus in the blood is measured and used as an indicator of disease severity. What makes the findings of this study so ground-breaking is that we may have a non-invasive way to track dengue infections in our patients more accurately during clinical trials to better measure if the experimental treatment given is effective.”

A joint venture between SGH and Duke-NUS is now in the works to determine if these basic laboratory findings are applicable in real dengue patients. At the moment, they are recruiting dengue patients as volunteers. The aim here is to use non-invasive PET-FDG imaging to modify the assessment of latest dengue treatments in clinical trials to successfully treat infections in a clinical setting. MIMS

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