A group of researchers from University of California, San Francisco (UCSA) have stumbled upon a peculiar protein that alters the form of fat tissues (Bardi 2012). This protein was first discovered in mice but it also exists in humans as well. This protein is called PRDM16 and it activates a process that coverts energy storing white adipose tissue (WAT) to exergonic brown adipose tissue (BAT).
While the exact process of this conversion is still unknown, it appears that PPARγ ligand drugs that undergo full agonisation like the anti-diabetic drug Rosiglitazone are able to consolidate levels of PRDM16. Through stabilising and accumulating of PRDM16, fat tissues in mice are observed to be ‘brown’. This means the WAT are somehow induced into BAT based on the levels of PRDM16. Extending this concept to humans, this could possibly forge new ground in obesity drugs.
At present, drugs like Xenical and alli (Hensrud 2012) inhibit the function of lipase – the enzyme in our small intestine that breaks down fat in the digestive tract, to reduce the uptake of fat by the body and eventually cutting down the overall calorie absorption by the body. With the discovery of PRDM16, further studies can be done to identify other sources that can facilitate this protein and possibly improve the rate of calorie consumption. This could possibly revolutionise the idea of weight loss by coupling burning calories and a healthy diet as opposed to strictly restricting intake.
You might be wondering where brown fat comes from! Enerbäck (2010) postulated that brown adipose tissue or brown fat came from our mammalian ancestors when they were trying to maintain a constant body temperature during the harsh winters. Brown fat contains large amounts of mitochondria that would explain its ability to generate heat by consuming energy.
Figure 1: Brown adipose tissue
Source: ScienceDaily 2012 [Available at http://www.sciencedaily.com/releases/2012/03/120307184658.htm]
Another interesting discovery by Vijgen et al. (2011) is that the amount of BAT in the human body is inversely proportional to chance of obesity. This simply means that higher brown fat levels will decrease the chance of obesity. While BAT is much more prevalent in new-born babies than adults, the discovery of the correlation of PRDM16 and BAT would allow us to possibly control the amount of BAT present in the body and reduce the occurrence of obesity.
In conclusion, while it is not certain when this ‘browning’ process of fat tissues or the effects of Rosiglitazone on PRDM16 in humans will be fully discovered, there is definitely a direction for future researchers with regards to tackling levels of obesity and brings hope to many people suffering from obesity who might want to effect a change in their lives.
Bardi, J 2012, Teaching fat cells to burn calories: new target against obesity involves brown fat, 7 March, ScienceDaily, viewed 12 March 2012, <http://www.sciencedaily.com/releases/2012/03/120307184658.htm>
Enerbäck, S 2010, ‘Human Brown Adipose Tissue’, Cell metabolism, vol. 11, no. 4, pp. 248-252, viewed 12 March 2012, <http://www.sciencedirect.com/science/article/pii/S1550413110000781 >
Hensrud, DD 2012, Weight loss, 11 February, Mayo Clinic, viewed 19 March 2012, <http://www.mayoclinic.com/health/alli/WT00030>
Vijgen, GHEJ, Bouvy, ND, Teule, GJJ, Brans, B, Schrauwen, P & van Marken Lichtenbelt, WD 2011, ‘Brown Adipose Tissue in Morbidly Obese Subjects’, PLoS ONE, vol. 6, no. 2, viewed 18 March 2012, <http://www.plosone.org/article/info:doi%2F10.1371%2Fjournal.pone.0017247>