No sleep for one night increased levels of the Alzheimer’s disease biomarker tau among young, healthy men, according to results of a two-condition crossover study published in Neurology.
“Based on the emerging line of data, it is becoming clearer that sleep may be an important lifestyle factor that modulates the prospective risk of Alzheimer's disease,” Jonathan Cedernaes, MD, PhD, of the department of neuroscience at Uppsala University in Sweden, told Healio Psychiatry. “Sleep problems in middle age have also been associated with an increased risk for later developing Alzheimer's disease, and a recent review calculated that about 15% of Alzheimer's disease cases may be related to sleep disruption. Although it is far too early to start making individual risk calculations or assessments based on blood biomarker changes in response to sleep loss, it may soon be worthwhile to consider sleep as a clinical lifestyle variable in the context of long-term brain health, especially in those who are already at an increased risk for developing Alzheimer's, such as in individuals with specific genetic risk factors.”
According to Cedernaes and colleagues, disrupted sleep increases cerebral spinal fluid levels of tau and beta-amyloid, both of which are associated with an increased risk for Alzheimer’s disease. To determine whether acute sleep loss altered diurnal profiles of these and other plasma-based biomarkers linked to the disease, the researchers recruited 15 healthy young men with an average age of 22 years. In randomized order, the participants were observed in two standardized sedentary in-laboratory conditions — normal sleep vs. overnight sleep loss. The researchers used ultrasensitive single molecule array assays to assess plasma levels of total tau (t-tau) and four other biomarkers in the fasted state in the evening prior to, as well as in the morning after, each intervention.
The researchers found that the participants had an average 17% increase in tau blood levels after a night of sleep loss vs. an average 2% increase in tau levels after normal sleep. The four other measured biomarkers exhibited no changes in levels between normal sleep and sleep loss.
“We also found that some of the biomarkers that are used to evaluate damage to the brain and that may be used to predict risk for Alzheimer's disease exhibit rhythmic changes,” Cedernaes said. “That is, they change in their levels from evening to morning. This is relevant as timing of day may need to be considered when such biomarkers are obtained in the clinic.” – by Joe Gramigna
Disclosures: Cedernaes reports no relevant financial disclosures. Please see the study for all other authors’ relevant financial disclosures.