In many ways, our brain and digestive tract are deeply connected. Nervousness can cause physical pain in the stomach, while hunger signals from the intestines make us feel irritable. Recent studies have even shown that the bacteria living in our intestines can influence some neurological diseases.
Modeling these complex interactions in animals like mice is difficult because their physiology is very different from that of humans. To give researchers a better understanding of the gut-brain axis, MIT researchers have developed an “organ-on-a-chip” system that simulates the interactions between the brain, liver and large intestine.
With this system, the researchers were able to model the influence that microbes living in the intestine have on both healthy brain tissue and on tissue samples from patients with Parkinson’s disease. They found that short-chain fatty acids, which are produced by microbes in the gut and transported to the brain, can have very different effects on healthy and diseased brain cells.
While short chain fatty acids are largely beneficial for human health, we’ve observed that, under certain conditions, they can further exacerbate certain brain pathologies such as protein misfolding and neural death related to Parkinson’s disease.
Martin Trapecar, MIT postdoc and lead author of the study.
Linda Griffith, professor at the School of Engineering for teaching innovation and professor of biotechnology and mechanical engineering, and Rudolf Jaenisch, MIT professor of biology and member of MIT’s Whitehead Institute for Medical Research, are the lead authors of the paper appearing today in Science Advances.
In the new study, the MIT team decided to add the brain and circulating immune cells to their multi-organ system. The brain has many interactions with the digestive tract that can occur through the enteric nervous system or through the circulation of immune cells, nutrients, and hormones between organs.
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