PhD student Cindy Yeung wins prestigious CIHR doctoral funding
Cindy completing her reserach project from home. Cindy’s CIHR proposal was ranked first out of the 290 applicants in her application pool.
For many new mothers, breastfeeding and medication use can be complicated. In some cases, medication taken by a mother can be transmitted via breastmilk to the baby, creating a potentially dangerous situation for the infant. As a precaution, breastfeeding women are often advised to avoid taking certain medications or to stop breastfeeding if on specific therapies. Sometimes, this advice is not directly supported by evidence; instead, health care providers exercise caution because of uncertainty. Often, the pharmacokinetics, or how a drug behaves in the body, of many medications are not well understood when it comes to infants.
Cindy Yeung, a PhD student in Dr. Andrea Edginton’s lab at the School of Pharmacy, is filling this knowledge gap with her PhD project “Pediatric physiologically-based pharmacokinetic (PBPK) modeling to advance knowledge of breastfeeding infant exposure to maternal medications.” This project has been awarded funding from the Canadian Institutes of Health Research (CIHR), and Cindy will receive $105,000 for her research over a period of three years. The funding will support the necessary tools to do the work and may also enable Cindy to develop new research partnerships. Currently, the project is being completed in collaboration with SickKids hospital in Toronto and with Sainte-Justine University hospital in Montreal.
“We’re collaborating with Dr. Shinya Ito at SickKids to collect milk samples from mothers, as well as optional blood samples from the mothers and their infants,” says Cindy. “The samples are analyzed by our partner Dr. Julie Autmizguine in Montreal and that data comes to us at Waterloo.”
Cindy works with the data to build computer models that can predict how much drug exposure a baby will receive if the mother is taking the medication while breastfeeding. These are called physiologically-based pharmacokinetic (PBPK) models, and they take into account many factors that have not been previously considered in assessing infant risk during breastfeeding.
Using PBPK we overcome some of the challenges that are inherent in pediatric research. We use computer simulation to safely and accurately model a child’s physiology and anatomy. We can use existing literature to input data that simulate real blood flow and organ size of infants. Having precise inputs for factors like those give us more confidence in our model and allow us to reach informed conclusions about dosing and safety without impacting real infants.
Cindy and her collaborators are studying seven specific drugs and have a goal of enrolling up to thirty-five mother and infant pairs for each of those drugs. These drugs were chosen either because there are reported cases of toxic effects of the drug transmitted to the infant through breastfeeding, or because they are medications whose discontinuation could be harmful to the mother.
Cindy will use the breastmilk samples collected by SickKids to assess the concentration of the seven study drugs in the milk. That concentration number, along with the volume of breastmilk intake, will be used to obtain a daily infant dose that will be inputted into the model. The model will simulate the drug exposures to the virtual infant populations she is creating. The result will be a novel drug in milk risk assessment metric – a measure that will allow health care providers to make informed decisions about whether or not a mother should discontinue taking a specific medication or breastfeeding.
Cindy also receives the Nelson Mandela Honour with her funding; only the two highest-ranked CIHR applications receive the honour. This additional recognition is especially meaningful to Cindy and her research, as children’s health was one of the five areas championed by Nelson Mandela in his lifetime. Breastfeeding has the potential to prevent up to 800,000 deaths annually in children under five around the world.
Breastfeeding is a universal experience for mothers. Our research will inform decisions about whether or not a mother can continue to breastfeed or take a certain medication while breastfeeding. If a mother is able to breastfeed there are positive outcomes for both the baby and the mother, and so I’m excited able to contribute to an improved metric that will make that decision easier for families and clinicians.