Sunday, 20 May 2012

A Cure For Obesity?


Obesity is a major health concern all over the world. It can activate many other diseases including diabetes. Obesity is defined by the increased body weight caused by excessive accumulation of fat and the latest data recorded estimates that there are at least 300 million obese people in the world [1]. Scientific researchers are constantly searching for efficient and effective ways to help reduce the risk of obesity. It wasn’t until recently that new research from the University of California, San Francisco suggested that ordinary fat cells can be reengineered to burn calories.
Image 1: Image of white fat cells [6].

Basically we have two different kinds of fat cells; white fat cells that store excess energy and, accumulate when weight is gained and brown fat cells which oxidize fuels and dissipate energy in the form of heat. Brown fat cells are the main interest, as experiments have shown they have the potential to counteract obesity. However these brown fat cells exist only in large doses in mice and infants. Adult humans do not have distinct brown fat, but they do appear to have small numbers of brown fat cells in white fat. So therefore to reduce the risk of obesity our bodies need to contain a larger amount of brown fat. Recently while investigating how a common drug given to people with diabetes works in mice, the University of California, San Francisco discovered a protein called PRDM16; found in both men and mice, can throw a switch on fat cells converting them from ordinary calorie-storing white fat cells into calorie-burning brown fat cells [2]. This protein, PRDM16 also is encoded by a gene known as the zinc finger transcription factor that mediates protein-to-protein interactions [3]. This protein can therefore assist the body in converting stubborn white fat cells into active brown fat. However to successfully complete this transition, the protein needs to be stabilized by a safe compound that enables PRDM16 to accumulate and activate receptors that induce brown fat cells before the protein breaks down [3].
Image 2: A scanning electron micrograph of
brown fat tissue [5].

Several experiments have been in place over the past few years to test this theory. As mentioned earlier mice contain large amounts of brown fat and therefore made the perfect test subjects. In the laboratory research, obese, male mice aged 3-4 weeks were injected with many types of drugs that had the potential to raise PRDM16 levels and therefore stabilizing the protein to promote the conversion of white fat cells into brown fat cells [4]. One of the most effective drugs proven was the irisin hormone and within 10 days of treatment, the rodents’ blood sugar and insulin levels stabilized; preventing the onset of diabetes and they lost weight [4].

These experiments have not yet been tested on humans, however given that the mouse and human forms of the protein PRDM16 are quite similar there is a possibility that these same results will occur in humans; therefore will counteract obesity [3]. The irisin hormone however being effective on mice still may have the possibility to prove ineffective on humans and therefore scientists are continually researching new drugs that target PRDM16 protein to raise and stabilize its levels and therefore offering new hope in the fight against obesity.

References:

1.     World Health Organization 2011, Obesity and Overweight, Viewed 16 March 2012,

2.     Science Daily 2012, Teaching Fat Cells to Burn Calories: New Target Against Obesity Involves Brown Fat, Viewed 13 March 2012,
     < http://www.sciencedaily.com/releases/2012/03/120307184658.htm>

3.      Seale, P & Kajimura S 2007, ‘Transcriptional Control of Brown Fat Determination by PRDM16’, Cell Metabolism, vol. 6, no. 1, pp. 38-54.

4.     Saliba, J 2012, Harvard Biology Research Isolates Hormone Response to Exercise, Towards Obesity Treatment?, Biotechnology Calendar, Inc., Viewed 16 March 2012,

5.      Gregory, D & Marshall, D 2009, A Scanning Electron Micrograph of Fat Tissue, National Institutes of Health..

6.   Kanas City University of Medicine and Biosciences 2010, White Fat. 


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