A rare genetic disorder, Bardet-Biedl syndrome (BBS) is known to interfere with the brain’s ability to signal the body to stop eating when enough food has been consumed. The brain uses the hormone leptin to signal satiety. Leptin is also associated with high blood pressure.

University of Iowa (UI) researchers studying BBS in mice found that when a certain protein is lacking or defective, the leptin signal is disrupted. Leptin suppresses appetite and increases the body’s ability to use calories.

In laboratory experiments, mice were injected with daily doses of leptin. Mice with genetic defects that cause BBS could not control their appetites and gained weight. Mice without BBS that received the leptin injections lost weight.

Kamal Rahmouni, PhD, principal investigator for the study, says leptin is made in fat tissue and is instrumental in the body’s ability to burn stored fat. He says finding high levels of the hormone in the bloodstreams of obese people is an indicator of leptin resistance. He considers leptin an excellent candidate for the study of the causes of weight gain.

An additional discovery in the mice experiments revealed problems of high blood pressure in the mice that had a specific kind of defective protein associated with leptin and BBS. Researchers chemically blocked neurotransmission of the defective protein genes and successfully lowered blood pressure levels in the mice.

BBS is so rare only about one in 10,000 people is diagnosed with it. Due to such a small human population to study, the mice have proven instrumental in identifying potential treatment options that can possibly be adapted for use in humans suffering from BBS. At this time, there are no recommended treatments for treating high blood pressure in BBS patients.

The March 3 online edition of the Journal of Clinical Investigation carries full details of the UI study.

Source: University of Iowa Health Sciences