Journal Digest

Gut Bacteria Linked to Autism-Like Behavior in Mice

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Over the past decade, several studies have shown an association between gastrointestinal distress—in both offspring and mother—and autism spectrum disorder (ASD). A study published in Cell found that the gut bacterium Bacteroides fragilis (B. fragilis) may be a potential target to alleviate behavioral symptoms associated with ASD.

Researchers from the California Institute of Technology conducted a study in which they observed gastrointestinal and behavioral abnormalities in pups of a maternal mouse model that is prone to yield offspring with neurodevelopmental disorders, including ASD.

They found that offspring with ASD-like symptoms were plagued with gastrointestinal abnormalities and changes in the gut microbial community, which lacked B. fragilis. When offspring were given B. fragilis, both their gastrointestinal abnormalities and anxiety-like behavior greatly improved.

“Taken together,” the researchers said, “these findings support a gut-microbiome-brain connection in a mouse model of neurodevelopmental disorders and identify a potential probiotic therapy for gastrointestinal and behavioral symptoms in human disorders, including autism.” They added that human trials are now needed to gather the evidence to verify the link that was found in mice.

Risk for Depressive Symptoms Decreases After Menopause

Researchers in the departments of Obstetrics/Gynecology and Psychiatry at the University of Pennsylvania conducted a study with 203 late-reproductive women to assess the changes in depressive symptoms surrounding menopause. The study was initiated while participants were premenopausal and ended during their postmenopausal stage.

The results showed that overall risk was higher in the years prior to menopause and lower in years after menopause. Among women with a history of depression, an average of 58 percent each year of the study were diagnosed with clinical depression before the final phase of menopause; this decreased to 35 percent each year during postmenopause. Women with no history of depression had a low risk for developing depression before menopause, and even lower risk after menopause. These results remained consistent regardless of race, age of menopause onset, and body mass index.

Decrease in depressive symptoms during postmenopause was also associated with each unit increase in follicular stimulating hormone blood levels. There was no significant association between the rate of change of other prevalent female hormones such as estradiol or inhibin B.

“Although only a small percentage of women experience mood difficulties in relation to menopause, many want to know what to expect in this transition period. Women overall can expect depressive symptoms to decrease after FMP [final menopausal period], although those with a history of depression have a continuing high risk of recurrence,” the researchers concluded.

Repeated Viewing of Traumatic News Coverage Bad for Mental Health

Researchers from the University of California, Irvine, surveyed more than 4,500 adults up to a month after the 2013 Boston Marathon bombing to assess the mental impact of indirect exposure to trauma through media—including television, video, radio, and social media.

The findings showed that people exposed to more than six hours a day of bombing-related media coverage were nine times more likely to report high acute stress than those with less than one hour of daily exposure. Symptoms of mental distress included intrusive thoughts, feeling on edge, and hypervigilance.

“There is mounting evidence that live and video images of traumatic events can trigger flashbacks and encourage fear conditioning,” said E. Alison Holman, Ph.D., F.N.P., an associate professor of nursing science at UC Irvine and the study’s lead author. “There’s something about repeated exposure to violent images or sounds that keeps traumatic events alive and can prolong the stress response in vulnerable people.”

The authors emphasized that risk of developing acute stress through media coverage can be even greater in those with previous exposure to collective traumas or a preexisting mental health condition.

Cardiovascular Disease Linked to Dementia in Postmenopausal Women

Women with hypertension and diabetes may be at higher risk for cognitive decline over time, according to a study in the Journal of the American Heart Association.

Nearly 6,500 postmenopausal women aged 65 to 79 received neurocognitive exams to assess the effect of cardiovascular disease, diabetes, and adiposity on cognitive decline.

Results showed that postmenopausal women with heart disease or vascular disease—such as hypertension—were 29 percent more likely to experience cognitive decline than those without a cardiovascular disorder. Risk for cognitive impairment was doubled among women who experienced a heart attack compared with those who did not have such an event. Diabetes and a history of undergoing major cardiac surgery also increased risk for cognitive decline. Obesity was not found to alter cognitive function in older women.

“Women with heart disease should be monitored by their doctors for potential cognitive decline,” said Bernhard Haring, M.D., M.P.H., a clinical fellow in the Comprehensive Heart Failure Center at the University of Würzburg in Germany. “It is also very important to adequately manage heart-disease risk factors such as high blood pressure and diabetes.”

The researchers concluded that more studies are warranted on how preventing cardiovascular disease may preserve cognitive health. ■