London - Botox, the anti-wrinkle treatment, is being tested as a way to tackle obesity in a new trial on patients in Norway.
When injected into stomach wall muscles, it slows the speed at which food travels through the stomach — in theory, this makes patients feel fuller for longer, so they eat less. Animal studies have suggested it could reduce weight by up to a third in five weeks.
About a quarter of British adults are obese. Diet, exercise and drugs are used to treat it; in severe cases, surgery is an option.
On the NHS, surgery is available for people with a body mass index (BMI) of 40 or above — or 35 or above if they also have another serious condition that weight loss could improve, such as type 2 diabetes or high blood pressure.
There are two common types of surgery. In gastric banding a band fits around the top of the stomach, causing a feeling of fullness after a small amount has been eaten.
With gastric bypass, the stomach is surgically reduced in size so that it fills quickly. But the risks of surgery include infection and blood clots.
In the longer term, one patient in 12 develops gallstones, as rapid weight loss affects the body’s natural salts.
In one gastric bypass patient in five, the junction connecting the smaller stomach pouch to the small intestine becomes blocked with food, triggering vomiting.
One gastric band patient in 2 000, and one gastric bypass patient in 100, dies after having the operation.
Botox has fewer side-effects, is minimally invasive and cheaper than surgery. The treatment is based on the toxin produced by the bacterium Clostridium botulinum, and works by blocking signals from nerves to muscles, reducing muscle contractions.
In the new trial at Trondheim University Hospital, Norway, an endoscope — a long tube with a camera at the end — is inserted via the patient’s mouth into their stomach. The toxin is injected into the stomach wall with a needle that goes down the endoscope.
The researchers say Botox slows the speed food goes through the stomach by up to 50 percent.
In previous research at the Catholic University in Rome, Botox or a placebo was injected into rats’ stomachs. Those treated with the toxin lost 8.2 percent of their body weight and ate half as much food as the placebo rats.
In another animal study, Botox was injected into the vagus nerve in the stomach, which passes “fullness” messages to the brain and controls food passing through the intestines. The Botox “paralysed” the nerve and the animals ate less, losing 20 to 30 percent of their body weight over five weeks.
However, a study on humans by the American Gastroenterological Association found while Botox slowed stomach emptying, it didn’t lead to significant weight loss.
The researchers conducting the new trial say previous studies have been small and poorly designed.
* Meanwhile, scientists believe they have found the key to treating obesity after discovering that ‘switching off’ nerve cells in the brain caused mice to eat less.
Their study, published in the journal Nature Neuroscience, focused on dopamine, a brain chemical.
When researchers activated dopamine receptor cells in the mice’s prefrontal cortex — the decision-making area of the brain — the animals ate more; inhibiting the cells made them eat less.
Because the prefrontal cortex intersects with the amygdala, which processes emotional responses, the researchers believe this junction could be where eating behaviour is regulated. - Daily Mail