Adult stem cell study shows fish oil may help with depression

Researchers use stem cells from adults with depression to test treatments

June 11, 2020

Science Daily/University of Illinois at Chicago

A study published in Molecular Psychiatry shows that patient-derived adult stem cells can be used to model major depressive disorder and test how a patient may respond to medication.

Using stem cells from adults with a clinical diagnosis of depression, the University of Illinois at Chicago researchers who conducted the study also found that fish oil, when tested in the model, created an antidepressant response.

UIC's Mark Rasenick, principal investigator of the study, says that the research provides a number of novel findings that can help scientists better understand how the brain works and why some people respond to drug treatment for depression, while others experience limited benefits from antidepressant medication.

"It was also exciting to find scientific evidence that fish oil -- an easy-to-get, natural product -- may be an effective treatment for depression," said Rasenick, UIC distinguished professor of physiology and biophysics and psychiatry at the College of Medicine.

Major depressive disorder, or depression, is the most common psychiatric disorder. Around one in six individuals will experience at least one depressive episode in their lifetime. However, antidepressant treatment fails in about one-third of patients.

In the study, the UIC researchers used skin cells from adults with depression that were converted into stem cells at Massachusetts General Hospital and then directed those stem cells to develop into nerve cells. The skin biopsies were taken from two types of patients: people who previously responded to antidepressant treatment and people who have previously been resistant to antidepressants.

When fish oil was tested, the models from treatment-sensitive and treatment-resistant patients both responded.

Rasenick says the response was similar to that seen from prescription antidepressants, but it was produced through a different mechanism.

"We saw that fish oil was acting, in part, on glial cells, not neurons," said Rasenick, who is also a research career scientist at Jesse Brown VA Medical Center and president and chief scientific officer at Pax Neuroscience, a UIC startup company. "For many years, scientists have paid scant attention to glia -- a type of brain cell that surrounds neurons -- but there is increasing evidence that glia may play a role in depression. Our study suggests that glia may also be important for antidepressant action.

"Our study also showed that a stem cell model can be used to study response to treatment and that fish oil as a treatment, or companion to treatment, for depression warrants further investigation," Rasenick said.

https://www.sciencedaily.com/releases/2020/06/200611143054.htm

Researchers identify glial cells as critical players in brain's response to social stress

August 13, 2019

Science Daily/Advanced Science Research Center, GC/CUNY

Exposure to violence, social conflict, and other stressors increase risk for psychiatric conditions such as depression and post-traumatic stress disorder. Not everyone who experiences significant stress will develop such a response, however, and the cellular and molecular basis for an individual's underlying resilience or susceptibility to stressful events has remained poorly understood. Now, a newly published paper in the journal eLife from researchers at the Advanced Science Research Center (ASRC) at The Graduate Center, CUNY suggests that the behavior of oligodendrocytes -- the glial cells that produce the myelin sheath that protects nerve fibers -- plays a critical role in determining whether we succumb to or tolerate stress.

"Through our study, we were able to identify brain-region-specific differences in the number of mature oligodendrocytes and in the content of myelin between two groups of mice who were categorized based on their resilience or susceptibility to an identical social-defeat stressor," said the paper's corresponding author Jia Liu, a research associate professor with the ASRC's Neuroscience Initiative. "After repeated exposure to an aggressive mouse, some animals, called "susceptible," avoided any sort of social interaction with their peers, while others remained resilient and continued to be socially engaged."

In follow-up brain tissue analysis, the research team detected fewer mature oligodendrocytes and irregular myelin coverage in the medial prefrontal cortex -- a brain region that plays a critical role in emotional and cognitive processing -- in the susceptible mice. In contrast, healthy numbers of oligodendrocytes and myelin were detected in resilient mice.

Methodology

For the study, researchers exposed test mice to an aggressor for five minutes daily over 10 days. Following this period, the mice were placed in the presense of unfamiliar mouse and categorized either as susceptible if they showed signs of social withdrawal or resilient if they still showed interest in socializing with the new mouse -- a social behavior that is typically detected in normal mice.

Reseachers next sought to determine if there were myelination differences between susceptible and resilient mice. They looked at two areas of the brain that are known to play a critical role in determining the individual's response to stress. In one of those areas -- the medial prefrontal cortex -- they found that the myelinated segments of nerve fiber in susceptible mice were shorter in length and thinner than typical. They did not find this condition in the resilient or control mice groups. They also investigated the state of each mouse group's glial cells, and discovered that in susceptible mice fewer of these cells had differentiated into myelin-producing oligodendrocytes.

In a final experiment, researchers found that induced damage to the myelin in the medial prefrontal cortex caused altered social behavior in mice, but the behavior returned to normal when new myelin was formed.

"Dr. Liu's research has highlighted the importance of stressful social events in changing the epigenetic code of oligodendrocyte progenitors, which may account for the increased susceptibility to developing chronic psychiatric disorders in some individuals," said Patrizia Casaccia, founding director of the ASRC Neuroscience Initiative. "Her data suggest that oligodendrocyte progenitor differentiation can be affected by emotional and psychological events, and this provides a new concept for preventing and treating depression. Current treatments target neuronal function, but Dr. Liu's work identifies potential new therapy targets as it suggests glial cell dysfunction could be a cause of stress-related mental disorders."

https://www.sciencedaily.com/releases/2019/08/190813080212.htm