Credit: University of Illinois College of Agricultural Sciences, Consumer and the Environment
Urban, Illinois. When scientists need to understand the effect of new infant formula components on brain development, it is rarely possible for them to conduct preliminary safety studies in humans. After all, few parents are willing to hand over their newborn to test unproven ingredients.
Enter the domestic pig. Their brain and gut development is amazingly similar to babies – much more than traditional lab animals, rats and mice. Like infants, piglets can be examined using clinically available equipment, including non-invasive or magnetic resonance imaging. This means that researchers can test nutritional interventions in pigs, look at their effects on brain development via magnetic resonance imaging, and make informed predictions about how these nutrients will affect infants.
For nearly a decade, scientists relied on an MRI-based map, or atlas, of the pig brain – developed at the University of Illinois using 4-week-old pigs – to understand where and how nutrients and other interventions affect the developing brain. Now, Illinois scientists have updated this atlas, quadrupled the accuracy of this atlas, and also added a new atlas of 12 week old pigs.
The new atlases are available for free download at pigmri.illinois.edu.
“This improvement in spatial resolution makes a big difference when you look at the development in a piglet’s brain and try to see how your intervention changes the structure, size, or even function of the brain,” says Brad Sutton, professor in the Department of Bioengineering and Technical Director of the Center for Biomedical Imaging. At the Beekman Institute in Illinois, and co-author of the Brain Atlas Study, published in Journal of Neuroscience Methods.
“It’s about our ability to distinguish one part of the brain from another. The higher the precision, the more reliable we can say that this piece is the hippocampus, for example. Part of the brain,” adds Ryan Delger, associate professor in the department of animal science and chief author of the atlas. “The need for an atlas is for every research group working in this field to constantly refer to the same parts or regions of the brain. We have to have common terminology and infrastructure to speak the same language.”
To build the updated atlas, researchers anesthetized and screened pigs 4 to 12 weeks old at the Beekman Biomedical Imaging Center using the latest Siemens Prisma 3 T MRI equipment. The scans from multiple pigs in each age group were divided into one atlas for each age. , To calculate the variance between individuals. Next, the researchers identified and digitally isolated 26 regions of interest, such as the cerebellum, medulla, left and right cortices, and others, and provided volume parameters for each in the pig.
“We provide absolute and relative volumes not only for the whole brain, but for tissues such as gray matter, white matter, and cerebrospinal fluid, as well as all of the different areas of interest. These benchmark data can serve as a reference for other individuals who may be interested in knowing how a particular intervention affects the development of The brain or its development in the pig, “says Joan Fell, a PhD student in the Neuroscience Program in Illinois and lead author on the atlas study.
Researchers have used the previous pig brain atlas to advance neuroscience around the world, with around 450 downloads to date. The collective discoveries made available by the atlas go far beyond infant nutrition to include a deeper understanding of the germs, gut and brain axis, which appears to relate to common clinical conditions.
Delger says the new atlas will give researchers a more accurate view of the brain, enabling more advanced discoveries. And with the addition of the Atlas of older pigs, they will be able to expand their discoveries even further.
“At 24 weeks, or six months, the pig is sexually mature. We expect that by this age, the pig will have completed most, if not all, of its brain development,” Phil says. “So we are now able to see how our interventions affect development not only at a young age, but also into adulthood in pigs.”
Phil adds that the study also provides a detailed description of the process they used to create the atlas, giving researchers the blueprints for creating additional atlases for other animals.
But there is a lot to be said about pigs as an important animal in biomedical research.
“You can study the growth of the mouse brain, but for some studies, the mouse brain is not the same as the human brain in some important aspect. Also, you can’t really study the effects of the intervention on the brain directly in humans, because although we can get people into the scanner, We can’t always tweak their diet and test different ingredients, says Sutton.
“So the pig is right on that lovely spot: its brain is the right size to use human magnetic resonance imaging scanners and the pig brain is evolving closely with humans. And we have tools that enable us to study it in great detail, especially on this campus, and do cool things with it. To study the brain. “
Delger adds, “We are using actual human clinical equipment in the pig. We are effectively and non-invasively, taking a microscope into the pig’s brain while it is still alive. This is the point. We can take a virtual peek inside the pig’s brain several times throughout the pig’s life to see.” How the brain develops structurally. “
The article, “High-resolution MRI-based atlases of small and domesticated pigs (Sus scrofa)” was published in Journal of Neuroscience Methods [DOI: 10.1016/j.jneumeth.2021.109107]. Authors include Phil, Sutton, Delger, Sanjeon Jung, and Benjamin Zimmerman. Funding was provided by the US Department of Agriculture’s National Institute of Food and Agriculture.
The Department of Animal Science is located in the University of Illinois College of Agricultural, Consumer, and Environmental Sciences.