Scientists Find Link Between Bipolar Disorder And Neuroinflammation

A doctor views an image of a human brain taken by a positron emission tomography scan, also called a PET scan, on January 9, 2019, at the Brest Regional Hospital Center and University in France.

A doctor views an image of a human brain taken by a positron emission tomography scan, also called a PET scan, on January 9, 2019, at the Brest Regional Hospital Center and University in France.
Photo: Fred tanneau (fake images)

Scientists may be closer to understanding how the brain may function differently in people who have bipolar disorder. In a new study, researchers say they have found evidence that certain brain cells trigger inflammation more easily in those with BPD, and that these stubborn cells may be linked to decreased neural activity that could be harmful to our mental health. . The results, published Thursday in Stem Cell Reports, it could hint at a new way to treat bipolar disorder one day, though more research is still needed.

Scientists have been studying the connection between inflammation and mental illness for some time, including Bipolar disorder. People with bipolar disorder experience uncontrollable mood swings that can leave them severely depressed at one point and manic the next. It is known that people with bipolar disorder are more likely to have other conditions associated with chronic inflammation, such as hypertension and diabetes. Some studies have also shown that bipolar disorder patients may have higher levels of proteins that prompt the body to flare up, especially when they are in the middle of a manic episode. These proteins include interleukin 6 (IL-6), which performs many functions in the body, such as guiding the body’s acute response to infection.

In their new study, researchers from the Salk Institute for Biological Studies, the University of California at San Diego, and the Institute of Psychiatry and Neuroscience in Paris decided to analyze a specific type of brain cell, the astrocyte. These are star-shaped cells in the brain that carry out a number of important functions that help support neurons. One of these roles includes being part of the chain of command that triggers inflammation in the brain and the surrounding nervous system, which aims to help the brain respond to injury or infection. The researchers theorized that this generally This helpful process can go awry in people with bipolar disorder, and astrocytes can play a role in this dysfunctional inflammation.

“Due to a growing understanding of the role of neuroinflammation in psychiatric disorders, we asked whether altered signaling driven by inflammation in astrocytes was associated with bipolar disorder,” study author Fred Gage said in an email, President of the Salk Institute for Biological Studies. .

Gage and his team used stem derived cells of six people with bipolar disorder, as well as four controls without bipolar disorder, then had them become astrocytes that were studied in the laboratory. (They had discovered how to create these cells from previous research.) Compared with the control group, the astrocytes of patients with bipolar disorder were markedly different. The cells had higher expression of their IL-6 gene and, as a result, secreted more IL-6 than the control. astrocytes. When they exposed neurons to these astrocytes, the team saw decreased levels of neuronal activity, compared to astrocytes from the controls. And when the researchers introduced an antibody that suppressed IL-6 into the mix, neurons were less hampered by astrocytes, further implicating IL-6. Finally, the blood of the bipolar disorder patients also contained more IL-6 than the controls.

“Our study suggests that normal astrocyte function is impaired in the brains of patients with bipolar disorder, contributing to neuroinflammation,” said co-author Renata Santos, a researcher at the Salk Institute and the Institute of Psychiatry and Neuroscience of Paris.

The findings are certainly intriguing, but the researchers caution that there is still a long way to go before we can confirm a clear causal link between impaired astrocytes, IL-6, and bipolar disorder, much less something that could lead to new ones. significant treatments. Lab-grown astrocytes may be different from those found in our brains in important ways, for example. (One difference is that these cells are less mature.) And since the brain is quite complicated, there are likely other aspects of our biology, including the brain, that could play a role. role in causing bipolar disorder.

“Our findings clarify aspects of the little-studied role of astrocytes in neuroinflammation in psychiatric disorders, with relevance to altered IL-6 and inflammatory signaling in astrocytes from patients with bipolar disorder,” said lead author Krishna Vadodaria, researcher. associate of the Salk Institute.

If researchers are on to anything here, it is possible that astrocytes could not only help provide more information on bipolar disorder, but also on other inflammation-related mental illnesses, such as schizophrenia, according to study author Carol Marchetto, now anthropology researcher at UC San Diego. And they hope their work will help fuel future research on astrocytes and inflammation, research that could lead to the development of treatments that could reverse the harmful body changes seen in people with bipolar disorder and similar conditions.


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