ConcePTION is building a model that can predict how medicines transfer to breast milk. But because a mother’s milk is made just for her baby, we need to know how and if it is possible to compare humans to other animals. Part of that work is now published in a review where we map the anatomy, physiology and milk composition of the most common laboratory animals.
Breastfeeding has many benefits for both mother and baby. But because there is a lack of robust data on how medicines transfer to breast milk, many women choose not to breastfeed. We are developing a set of research infrastructures that together make up an ecosystem for evidence based information on medicine safety in pregnancy and breastfeeding. Data from animal studies will provide one small but important piece to solve this complicated puzzle. A recent review published in Animals provides a first step in bridging the knowledge gap for mother and baby!
Our model uses a combination of in silico, in vitro and in vivo studies, comparing the data from computer models, cell lines and animals against data from our milk biobank studies. This approach allows us to partially replace animals with other models and reduce the number of animals needed to answer our research questions. One important part of this approach is choosing the right animal model to use. A team of researchers from ConcePTION recently published a paper that summarizes the relevant anatomical and physiological features when it comes to lactation in the species that are most common in biomedical research.
According to one of the authors, Domenico Ventrella from the Department of Veterinary Medical Sciences at the University of Bologna, choosing the best animal model for a given study is often harder than the trial itself. “The decision should always take into account a wide array of factors, both animal and non-animal related. Nonetheless, it is important to remember that an animal model should serve as a surrogate, and it does not need to be identical to the modeled species”, he says.
The review shows that although the anatomy is very different between species, the physiology of the lactation itself is not that different between the different species that were part of the review. But there are other aspects that need to be considered. To refine the methods, there is another important aspect researchers need to take into account: testing milk requires milking.
“The more common laboratory animals are small, like rats or rabbits. And to be able to refine the methods and minimize pain and distress, choosing large animals instead, like dogs and pigs, would make it possible to take repeated samples in a responsible way”, says Alberto Elmi, as Research Fellow at the Department of Veterinary Medical Sciences
As you would expect, the milk from non-human primates is very similar to ours, but using apes for this kind of studies raises ethical concerns. In the paper, the authors conclude that the porcine species, commonly known as pigs, seems to be the best model for lactation studies: The translational value is high (meaning we can compare the results with humans). Because pigs are larger animals, is also possible to take samples from them in an ethically acceptable way, and it is also easier from the more practical perspective.
The studies that were included in the review had some inconsistencies. According to the authors, to be able to do safe and reliable comparisons between different animal models, the standards for developing data on colostrum (the first milk-like fluid that is released, before the more mature milk is produced) and milk composition need to be updated.
Want to read the paper?
Ventrella D, Ashkenazi N, Elmi A et al. Animal Models for In Vivo Lactation Studies: Anatomy, Physiology and Milk Compositions in the Most Used Non-Clinical Species: A Contribution from the ConcePTION Project. Animals, volume 11 (no 3), 714 (2021).
By Josepine Fernow