New findings in mice suggest that merely changing meal times could have a significant effect on the levels of triglycerides in the liver. The results of this Weizmann Institute of Science study, recently published in Cell Metabolism, not only have important implications for the potential treatment of metabolic diseases, they may also have broader implications for most research areas in the life sciences.
Many biological processes follow a set timetable, with levels of activity rising and dipping at certain times of the day. Such fluctuations, known as circadian rhythms, are driven by internal "body clocks" based on an approximately 24-hour period synchronized to light-dark cycles and other cues in an organism's environment. Disruption to this optimum timing system in both animal models and in humans can cause imbalances, leading to such diseases as obesity, metabolic syndrome and fatty liver. Night-shift workers, for example, have been shown to have higher incidence of these diseases.
In studying the role of circadian rhythm in the accumulation of lipids in the liver, postdoctoral fellow Yaarit Adamovich and the team in the lab of Dr. Gad Asher of the Weizmann Institute's Biological Chemistry Department, together with scientists from Dr. Xianlin Han's lab in the Sanford-Burnham Medical Research Institute, Orlando, US, quantified hundreds of different lipids present in the mouse liver. They discovered that a certain group of lipids, namely the triglycerides (TAG), exhibit circadian behavior, with levels peaking about eight hours after sunrise. The scientists were astonished to find, however, that daily fluctuations in this group of lipids persist even in mice lacking a functional biological clock, albeit with levels cresting at a completely different time 12 hours later than the natural schedule. "These results came as a complete surprise: One would expect that if the inherent clock mechanism is 'dead,' TAG could not accumulate in a
|Contact: Yivsam Azgad|
Weizmann Institute of Science