Monday, October 08, 2012
Why Fat People Can’t Help Getting Even Fatter
New research has found that a type of anti-tumour immune cell protects against obesity and the metabolic syndrome that leads to diabetes. Results showing that immune cells known to be protective against malignancy called invariant natural killer T-cells (iNKT), that are lost when humans become obese, but can be restored through weight loss, have been published online this week in the journalImmunity. Marie Curie Fellow, Lydia Lynch at Trinity College Dublin, Ireland made the discovery and as first author in collaboration with colleagues at Harvard-affiliated Beth Israel Deaconess Medical Centre, and St Vincent’s University Hospital have shown that therapies that activate iNKT cells could help manage obesity, diabetes, and metabolic disease.
Next, the authors removed iNKT cells from a normal mouse and injected them into obese NKT-deficient mice.
“We actually reversed the diabetes, and even though the mice continued to eat a high-fat diet, they lost one to two grams of weight [normal mouse weight being 20 to 25 grams] and exhibited a host of features that suggested reduced inflammation, including improved insulin sensitivity, lower triglycerides and leptin, and shrunken adipocytes,” Dr Lynch said.
Finally, in order to demonstrate if the remaining diminished pool of iNKT cells in obesity could be activated to improve metabolism, the scientists tested aGC, a lipid known to activate iNKT cells. They found that administering a single dose of aGC caused a dramatic improvement in metabolism and fatty liver disease, loss of much of the weight gained, and reversal of diabetes in the obese animals.
“aGC has been tested in clinical trials for the treatment of certain cancers, including melanoma, and proven safe and produced few side effects in humans,” said Exley. “The effect of NKT stimulation, whether by aGC or other means, on weight loss, obesity, and metabolic disorder has not been investigated until now and may provide a new avenue for the treatment of obesity and metabolic syndrome, which have now reached epidemic proportions worldwide.”