New study shows why heart failure patients experience depression
Heart failure patients often struggle with depression and impaired thinking, and a new study by researchers at the University of Guelph in Ontario, Canada, may explain why.
The study, published in the journal Scientific Reports, compared normal mice with mice carrying a mutation in their circadian mechanism, or “clock.” They found hat the mutation affected the structure of neurons in brain areas important for cognition and mood. The team also found differences in clock regulation of blood vessels in the brains of mice carrying the mutation.
After inducing heart failure in the mice, the researchers used microarray profiling to identify key genes in the brain that were altered in neural growth, stress, and metabolism pathways, according to the study abstract.
The results show that the circadian mechanism influences neural effects of heart failure, researchers said in a statement released by the university. The study is the first to reveal how cognition and mood in mice are regulated by the body clock and how pertinent brain regions are impaired in heart failure. No cure exists for heart failure and understanding how the circadian mechanism works in the brain may lead to new strategies to improve patients' quality of life, researchers said.
Patients recovering from heart attacks often experience disturbed circadian rhythms from light, noise, and interactions with hospital staff at night. Maintaining circadian rhythms, especially for patients with heart disease, could lead to better health outcomes, said Tami Martino, PhD, a professor in the Department of Biomedical Sciences and director of the Centre for Cardiovascular Investigations.
Human patients with heart failure often have neurological conditions such as cognitive impairment and depression, said Martino. Martino said she suspected the heart-brain connection involved the circadian mechanism molecule. Circadian rhythms in humans and other organisms follow Earth's 24-hour cycle of light and darkness, signaling when to sleep and when to be awake.
More generally, the findings point to potential health benefits for people in general. Avoiding shift work for people with underlying heart conditions or sleep disorders, reducing light at night, or avoiding social jet lag such as going to bed late and waking up later than usual on weekends, could all help reduce neurobiological impairments.
Those problems, and potential solutions, involve not just hearts but brains, said Martino.
"If we're not yet able to cure heart failure, she said, “we should at least be focusing on how we can improve quality of life for patients."