Less weight more brain

Ciliary neurotrophic growth factor (CNTF), was first identified as a protein that helps neurons survive and specialize. But researchers studying CNTF found an unexpected side effect: Mice and people given the compound lost their appetite and shed dramatic amounts of weight. And unlike most weight loss drugs, those taking CNTF or a related compound called Axokine didn't have the urge to binge as soon as treatment stopped. "Many of us found the effect absolutely stunning," says Jeffrey Flier of Harvard Medical School in Boston, Massachusetts.

A genetically engineered mutein of CNTF being tested under the name Axokine by Regeneron Pharmaceuticals for treatment of human motor neuron diseases.

Unfortunately people taking Axokine developed antibodies against the drug and the effects were short lived. However, Flier’s studies in mice showed that the drug stimulated neuronal growth in the brain’s hypothalamus know as a regulatory center. More neurons were created that responded to the natural appetite suppressor Leptin thus reducing hunger .

This drug is not a small molecule but a genetically engineered protein and therefore more likely to elicit an immune response than a small molecule. It is interesting that Regeneron is working on a PEGilated version of this protein. This process involves attaching molecules of the short polymer polyethylene glycol to the surface of the protein. The idea is that the PEG molecules keep the immune system from recognizing and attacking the protein so protected. Perhaps there is more to come.