An organoid is a tiny, simplified version of an organ derived from stem cells. They replicate much of the complexity of an organ and have become known from human research. Wageningen University & Research (WUR) is growing, for example, mini-guts from pigs and fish and mini-airways from cows and pigs to study animal nutrition and health. Five questions to animal scientists Soumya Kar and Esther Ellen.
Soumya: "Yes, within WUR we started developing organoids from pigs. Now we are still one of the pioneers in this particular field. There are very few labs in the world that are currently working on the same thing. But, of course, much more research has been done on human organoids. This started around 2010 at the Hubrecht Institute. After a decade, these organoids have already achieved a lot in nutritional and pharmaceutical research and they are also pretty instrumental in diagnostics and even clinical treatment. So the human field is years ahead of what we're doing in livestock. I think we're just getting started."
Why do we need these miniature organs in livestock research?
Esther: "We see organoids as a good tool to replace animal experiments. They help to answer research questions in animal breeding and animal nutrition. For instance, why some pigs use feed more efficiently than other pigs. This is a quite complex trait of an animal. Organoid research can help us identify differences between individual animals. Our organoids are also useful to test specific ingredients of animal feed. In the future they might also be valuable for questions on animal health and pharmaceutics."
Soumya: "So we use pigs with different genes for our organoids. Let's say we have pigs with genes providing a high feed efficiency and other pigs with genes for a low efficiency. Then we derive organoids from their intestinal stem cells and try to understand the differences in their functioning."
Esther: "If we are able to use organoids to understand complex traits, then we can also use them as a tool for selecting animals more specifically for new traits, without increasing the number of animal experiments. For example, traits like nutrient utilisation and manure production. That's what we would like to achieve."
Do you think it will make a big difference in the number of animal experiments?
Soumya: "I think organoids will play a crucial role in the search for alternatives for animal testing. That's our moral responsibility as animal researchers. Theoretically, many organoids from different tissues can be obtained from a single animal. This will help reduce the use of animals in experiments. However, we can't completely get rid of all animal experiments because organoids are still different from whole animals. But by using organoids some animal experiments aren't necessary anymore."
Can other researchers already knock on your lab's door if they want to collaborate?
Esther: "Yes, we are very open for collaboration and think that this is important to further explore this emerging field in human and animal sciences.
Researchers are very enthusiastic about our organoids, so we're continuing our pioneering work."
What are your next steps as organoid developers?
Soumya: "There are still so many questions that need to be solved in order to make our system more reproducible and overcome practical issues.
We are also working on other improvements. An organoid now contains one type of cell, because we start with adult stem cells. They are programmed to proliferate and differentiate into their own lineages. That's why blood vessels, neurons and immune cells are not yet part of the organoid. In the coming years we intend to study mixing and matching different cell lineages, for example an epithelial layer (intestinal cells in contact with food) with the immune cells. A system like this can be used to understand host-microbe interactions or diet-host interactions."
