Obesity impacts gene clock of cardiovascular system

Apr 12 2011

Obese individuals typically suffer more medical problems than their leaner counterparts. They are more likely to be diagnosed with insulin resistance, diabetes, increased stress hormones, hypothyroidism, and sleep apnea. Researchers at the Georgia Health Sciences University in Augusta have also found the potential for something else, using an animal model. They have found that a master clock gene - which regulates the cardiovascular system - does not fluctuate regularly as it does in non-obese animals. This means that a key gene clock of the cardiovascular system does not work properly when obesity is present. The findings are believed to be the first of their kind.

The study was conducted by Shuiqing Qiu, Eric Belin de Chantemele, James Mintz, David J. Fulton, R. Daniel Rudic and David W. Stepp. Members of the team will present their findings, entitled, "Impact of obesity on the vascular circadian clock," at the Experimental Biology 2011 meeting (EB 2011), being held April 9-13, 2011 at the Walter E. Washington Convention Center, Washington, DC.

Circadian Biology and Obesity
Humans and animals are essentially programmed to physiologically respond to a day/night cycles based on the 24-hour rotation of the planet. The body has been trained through evolution to respond to day cues by eating and perusing activities and to rest and sleep cues during darkness. Indeed, there is a molecular basis that precisely controls rhythms, a group of genes dubbed the circadian clock, including one molecule also aptly named 'Clock'.

In obese individuals, the natural circadian rhythms are believed to be disrupted. Obese individuals frequently eat at irregular times, and especially late at night. In addition, they often suffer from sleep apnea, which disturbs their sleep rhythm thus causing them to miss a good night's sleep. Shift workers tend to be obese because their physiological requirements are backwards (breakfast may start at 10:00 p.m.) and swing shift workers (who work a week on the day shift followed by a week on the night shift) are predisposed to obesity because their physiological cues "swing" back and forth thus interrupting the natural circadian rhythms.