They are the building blocks of flab, the wages of cheesecake, the bloated little sacks of grease that make more of us -- more than we can fit into our pants.

Scorned and despised, they are sucked out surgically by the billions from bulging backsides, bellies and thighs.

But they are not without admirers.

"Fat cells are beautiful cells to look at," said Dr. Philipp E. Scherer, associate professor of cell biology and medicine at Albert Einstein College of Medicine in New York. "I've been working with them for 10 years and I still enjoy looking at them."

On a recent afternoon at his lab, Scherer slipped a Petri dish of fat cells under a microscope and showed how strikingly they caught the light and reflected it. Magnified, they became a field of glittering rings.

Scientists used to think body fat was pretty much inert, just an oily storage compartment. But in the past decade research has shown that fat cells are chemical factories and that body fat is potent stuff: a highly active tissue that secretes hormones and other substances with profound and sometimes harmful effects on metabolism, weight and overall health.

In recent years, biologists have begun calling fat an "endocrine organ," comparing it to glands such as the thyroid and pituitary, which also release hormones straight into the bloodstream.

But those glands cannot grow nearly as much as fat, which has a seemingly infinite capacity to make more of itself. Too much body fat can act like a poison, spewing out substances that contribute to diabetes, heart disease, high blood pressure, stroke and other illnesses, including some cancers.

Researchers trying to decipher the biology of fat cells hope to find new ways to help people get rid of excess fat or, at least, prevent obesity from destroying their health. In an increasingly obese world, their efforts have taken on added importance.

Internationally, over a billion people are overweight. Obesity and two illnesses linked to it, heart disease and high blood pressure, are on the World Health Organization's list of the top 10 global health risks. And the incidence of Type 2 diabetes, almost always caused by obesity, has also been climbing around the world.

A lean adult has about 40 billion fat cells, an obese one at least two to three times that. And obese people have much larger fat cells than lean ones.

Even worse, the body can always make more, and compared with other cells they are extremely long-lived.

If a person keeps overeating, fat cells grow and grow, looking as if they are about to pop. When they reach the limit, they don't divide; they send out a signal to nearby immature cells to start dividing to produce more fat cells.

Some kinds of obesity are worse than others, and body shape matters.

People shaped like apples, carrying excess weight in the abdomen, are more likely to have diabetes and heart disease than are those built like pears, who deposit fat in their hips, thighs and backsides.

Women tend to be pears, but also redistribute fat and thicken in the middle after menopause. Ethnic groups vary. For instance, Asians are more likely to put weight in the abdomen and suffer health problems from lesser degrees of obesity.

Why should a big belly be more dangerous than a big backside? Many researchers think the culprit is visceral fat, deposits inside the abdomen, as opposed to subcutaneous fat, under the skin.

An apple-shaped person is sure to have visceral fat, as well as subcutaneous fat in the abdominal area.

Anybody with a belly has visceral fat, and the more you have, the worse off you are.

It is not clear why visceral fat is riskier; it may be more active metabolically and spew out more toxic substances. Also, its secretions go straight to the liver and may interfere with its functions, which include helping to regulate blood glucose and cholesterol.

In a study published this summer in the New England Journal of Medicine, doctors found that liposuction, which removes only subcutaneous fat, had no effect whatsoever on health, even when surgeons sucked out 20 pounds of subcutaneous abdominal fat.

But a person who loses that much weight through dieting and exercise will almost certainly see significant changes in blood pressure, cholesterol and insulin resistance.

Liposuction also fails to shrink the many more fat cells left behind.

The more metabolically harmful fat cells in obese people have 50 to 75 per cent more mass than fat cells in lean people, said lead author of the study Dr. Samuel Klein of the School of Medicine at Washington University in St. Louis.

The best way to get rid of visceral fat and shrink fat cells all at once is diet and exercise. Just a loss of 7 per cent of total body weight helps.

Something about burning more calories than you eat creates a state of negative energy balance that quickly melts away visceral fat and slims down bloated fat cells.

Unfortunately, diet and exercise have high failure rates. Since many people cannot lose visceral fat on their own, researchers have been experimenting with surgical removal.

Not all visceral fat can be removed safely because of where it is situated.

But a portion called the omentum can be taken out relatively easily, said Dr. Edward Mun, a surgeon at Beth Israel Deaconess Medical Center in Boston.

The omentum is a pad of fat weighing two to four pounds that hangs like a curtain in the abdomen. "We estimate that it's more than one-third of the visceral fat," Mun said.

He's doing a pilot study, performing the surgery on six obese, diabetic patients to see if it can reverse their diabetes.

For patients 100 pounds or more overweight, he frequently performs gastric bypass surgery, which shrinks the stomach and rearranges the small intestine to help patients lose large amounts of weight.

"It's the best thing we have," said Mun. "But I do not want the operation still to be around 100 years from now. To treat obesity, we have to understand how it arises. I really want to understand obesity."

Source:
diabetesnews.com