Gene therapy that melts away the fat

Main Category: Obesity / Weight Loss / Fitness
Article Date: 10 Feb 2004 - 0:00 PDT


American and Swiss scientists have used gene therapy to transform fat-storing cells into fat-burning cells. This could lead to a revolutionary new treatment for obesity.

The scientists added leptin (a protein) to cell. When they experimented on rats, the animals lost enormous amounts of weight (fat) without any side effects (apparently).

Some extremely obese people have had leptin injected into them. This work is still in its initial stages.

Scientists hope that leptin treatment will become more widespread.

They worked on rats that had been genetically predisposed to develop diabetes.

When they injected the rats with leptin (with a virus), they lost on average, 280 grams to 207 grams in 14 days. The rats also ate less and stayed healthy and active.

Energy centres

Microscopic evaluation of individual fat cells found that the cells shrank in size, and developed more energy centres called mitochondria.

In addition, levels of enzymes known to promote fat metabolism increased while those that impede fat metabolism decreased.

The rats showed no signs of the side effects associated with fat loss induced by starvation or insulin deficiency. These can include loss of lean body mass, hunger and the build up toxic substances called ketones in the blood.

The researchers also found that when they force-fed rats, those given the leptin gene put weight on at a slower rate.

The researchers stress that more work is needed to reveal the precise mechanism behind the changes.

However, they suggest that the results may have important implications for the treatment of obesity in humans.

Writing in the journal, they say: 'The fat loss induced here was far more rapid and profound than can be induced by caloric restriction.'

Lead researcher Dr Roger Unger, director of the Touchstone Center for Diabetes Research at the University of Texas Southwestern Medical Center in Dallas, said: 'The structure of the cells changed from the normal appearance of a fat cell to a very novel cell that's really never been seen before.

'There's no precedent for a cell that appears like this.' Leptin is normally produced by fat cells, or adipocytes, but is somehow prevented from interfering with the accumulation of surplus fat.

Scientists believe this is to ensure fat cells maintain their vital function of storing fuel during times of food shortage.

Dr Andrew Hill, chairman of the Association for the Study of Obesity, told BBC News Online a quick and effective treatment for obesity would be extremely welcome.

But he said: 'There is an enormous distance between what these researchers have done and a GP using it to treat 400-500 patients on their list for obesity.'

Dr Hill said many scientific advances had promised the prospect of a quick fix for obesity, but for most people the only solution was to work hard at maintaining a low weight throughout their life.

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