|
 |
 |
|
When
obese mice were injected with leptin, they slimmed down
to normal size.
|
|
Remember
leptin? Back in the mid-1990s, scientists discovered this
hormone that's secreted by fat cells to tell your brain you
don't need to lay down any more fat. When leptin was administered
to obese mice, they slimmed right down. But leptin wasn't
the hoped-for miracle cure in humans. Many obese people are
resistant to leptin and may already have very high levels
of the hormone in their blood. Scientists weren't ready to
give up on the leptin system as a way to fight obesity, though.
A naturally occurring molecule called Ciliary Neurotrophic
Factor (CNTF) has receptors similar to those for leptin that
are distributed in the same areas of the hypothalmus. And
CNTF produced anorexia and weight loss when it was first given
to people with Lou Gehrig's disease. Those patients certainly
didn't need to lose any weight, but researchers took note.
Regeneron Pharmaceuticals developed a modified version of
CNTF called axokine, and in trials it did help some obese
people lose weight. But about two thirds of the patients developed
antibodies to the compound. Regeneron says it's still testing
axokine — particularly to figure out why the drug works
well for some people and not for others — but has no
immediate plans to take it to the FDA.
Cancer
researchers stumbled onto another approach to fighting obesity
when they thought to turn one of their tumor-blasting techniques
onto fat cells. When tumors are starved of their blood supply,
they start to shrink. Could this work on fat as well? Both
kinds of cells rely on plentiful oxygen delivered via blood
so they can proliferate and expand quickly. Researchers designed
a protein that would home in on the blood vessels of white
fat and cause cell death. Lo and behold, when obese mice were
injected with the peptide they lost their excess fat, and
had higher metabolisms and more lipid turnover. This anti-obesity
compound is a long way from being approved for people, but
it underscores the multiple ways there are to skin a (fat)
cat.
 |
|
The
red arrows point to dead blood vessels in mouse tissue.
A protein that kills the blood supply for fat made
mice lose weight.
|
|
The
drugs mentioned here are just a small sample of what's in
the pipeline. There are anti-epilepsy drugs that have shown
promise in helping patients lose weight, but their side effects
need to be fine-tuned. Some antidepressants are being examined
for their weight-reduction potential. There's a drug under
investigation that helps burn fat — based on the enzyme
that's normally activated after exercise. The hunt is on for
drugs that combat obesity — and researchers are casting
a wide net.
"Obesity
is a chronic disease, like diabetes or high blood pressure,"
says Dr. Richard Atkinson, who heads the American Obesity
Association, an advocacy group. "Virtually every chronic disease
out there is treated with drugs, usually more than one." Now
that Medicare and Medicaid officially define obesity as a
disease, pharmaceutical companies may have even more incentive
to enter the anti-fat field since their newly developed drugs
are more likely to be covered at least partially by insurance.
In the long run, finding effective and safe ways to trim down
the population will save society money, predicts Dr. Louis
Aronne of NAASO. "We won't have to treat the diabetes, the
hypertension, the hyperlipidemia, and all the other problems
that come along with an increase in body weight," he says.
"This is going to be a very cost effective treatment."
 |
|
|
|
|
Of course, just like weight loss surgery, no medication is
a magic bullet — and this is especially true thanks to
the body's natural ability to resist losing weight. People
will probably always be able to defeat the effects of their
surgery or their pills if they want to. So patients will still
need to watch what they eat and stay active. But the jumpstart
to weight loss that new drugs may offer could be just what
the doctor ordered.
--------------------------
3 pages: | 1 | 2
| 3 |
|
