Is it possible for your liver to sense when you're staring at a television screen or cellphone late at night? When humans detect such activity, the organ can throw circadian rhythms out of whack, leaving you more susceptible to health problems.
Scientists from the University of California, Irvine, in collaboration with the Institute for Research in Biomedicine in Barcelona, Spain, have come up with new research.
The scientists have published findings of the study in the journal Cell, and they used specially bred mice to analyze the network of internal clocks that regulate metabolism. Director of UCI's Center for Epigenetics and Metabolism and senior author of one of the studies, Paolo Sassone-Corsi said that although the team suspected that the body's various circadian clocks could operate independently from the central clock in the hypothalamus of the brain, there was previously no way to test the theory.
Scientists figured out how to disable the entire circadian system of the mice to overcome that obstacle, then jump-start individual clocks. For the experiments reported in the Cell papers, they activated clocks inside the liver or skin.
Sassone-Corsi said further that the results were quite surprising. No one realized that the liver or skin could be so directly affected by light.
For instance, despite the shutdown of all other body clocks, including the central brain clock, the liver knows what time it was, responded to light changes as day shifted to night and maintained critical functions including preparing to digest food at mealtime and converting glucose to energy.
The liver's circadian clock, somehow, was able to detect light, presumably via signals from other organs. Only when they subjected the mice to constant darkness did the liver's clock stop functioning.
According to Sassone-Corsi, researchers at UCI and Barcelona will phase in other internal clocks to see how different organs communicate with each other in future studies.
He noted that the future implications of their findings are vast. With these mice, they can now begin deciphering the metabolic pathways that control human's circadian rhythms, aging processes, and general well-being.
Sassone-Corsi has examined how circadian clocks can be rewired by such factors as sleep deprivation, diet, and exercise in the previous studies. Exposure to computer, television, or cellphone light just before bed can also scramble internal clocks.
Due to modern lifestyles, he maintained, it is easy for people's circadian systems to get confused. In turn, that can lead to depression, allergies, premature aging, cancer, and other health problems. Sassone-Corsi added that further mice experiments could uncover ways to make human internal clocks "less misaligned."
