News briefs

The antioxidant benefits of sleep

Researchers from Columbia University in New York have found that short-sleeping fruit fly mutants shared the feature of sensitivity to acute oxidative stress, and concluded that sleep facilitates antioxidant processes. In a study published in PLoS Biology, the researchers reasoned that if sleep were required for a core function of health, animals that sleep significantly less than usual should share a defect in that core function. They examined a diverse group of short-sleeping Drosophila mutants and found that they indeed shared a common defect: they were all sensitive to acute oxidative stress. Oxidative stress results from excessive levels of free radicals that can damage cells and lead to organ dysfunction. Toxic free radicals, or reactive oxygen species, can accumulate in cells because of normal metabolism and environmental damage. If the function of sleep is to defend against oxidative stress, increasing sleep should increase resistance to oxidative stress. The effects of experimental pharmacological and genetic manipulations support this hypothesis. Finally, the authors proposed that, conversely, oxidative stress might regulate sleep. Consistent with this hypothesis, they found that reducing oxidative stress in the brain by overexpressing antioxidant genes reduced the amount of sleep. Taken together, these results point to a bidirectional relationship between sleep and oxidative stress; that is, sleep is important for defending the body against oxidative stress, and oxidative stress helps induce sleep. This work is relevant to human health because sleep disorders are associated with many diseases that are also associated with oxidative stress, such as Alzheimer, Parkinson and Huntington diseases. Sleep loss could make individuals more sensitive to oxidative stress and subsequent disease; conversely, pathological disruption of the antioxidant response could also lead to loss of sleep and associated disease pathologies.

http://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2005206

Iceman’s last meal was a fatty binge

Italian researchers have conducted the first in depth analysis of the stomach contents of the Iceman, a 5300-year-old human body discovered in 1991 in the eastern Italian Alps, the oldest naturally preserved ice mummy. Their findings indicate that the Iceman’s last meal was heavy in fat. Applying a complementary -omics approach combined with microscopy, they reconstructed the Iceman’s last meal. Writing in Current Biology, the researchers showed that he had a “remarkably high proportion of fat” in his diet, supplemented by wild meat from ibex and red deer, cereals, and traces of toxic bracken. The analysis was only recently undertaken because scientists were initially unable to identify the Iceman’s stomach, as it had moved up during the mummification process. In 2009, his stomach was identified during a re-investigation of computed tomography scans. Compared with previously analysed lower intestine samples, the stomach material was extraordinarily well preserved, and contained large amounts of unique biomolecules, such as lipids, that opened new methodological opportunities for investigating questions about the Iceman’s diet. The investigators combined classic microscopic and modern molecular approaches to determine the exact composition of his diet. The broad-spectrum approach allowed them to make inferences based on ancient DNA, proteins, metabolites, and lipids. The analysis identified ibex adipose tissue as the most likely fat source; in fact, about half of the stomach contents were adipose fat. While the high fat diet was unexpected, the researchers wrote that it made sense, given the extreme alpine environment in which the Iceman lived. The analysis indicated that the wild meat was eaten fresh or perhaps dried. While the presence of toxic bracken particles is more difficult to explain, the researchers suggest the Iceman may have had intestinal problems related to parasites found in his gut and took the bracken as a medicine. On the other hand, he may have used the fern leaves to wrap food and then unintentionally ingested toxic spores. The analysis also revealed traces of the original gut bacterial community present in the Iceman’s intestine. The researchers plan to conduct further studies to reconstruct the ancient gut microbiomes of the Iceman and other mummified human remains.

https://www.cell.com/current-biology/fulltext/S0960-9822(18)30703-6