21/8/2007 - 11:17(EST)

What Is Lipodystrophy?

Lipodystrophy is a combination of body changes observed in people taking antiretroviral drugs (ARVs). "Lipo" means fat and "dystrophy" means abnormal growth. These changes can be metabolic or fat loss and/or deposits.

Fat loss occurs in the arms, legs or face (sunken cheeks) and is maybe one of the most common features of lipodystrophy.

Fat deposits can appear in the stomach, back of the neck (buffalo hump), breasts (in men and women) or in other areas.

Metabolic changes include increased fats or lactic acid in the blood. Some people develop "insulin resistance".

• Blood fats include cholesterol and triglycerides.
• Lactic acid is produced when glucose (sugar) is used by the cells. Damage to the mitochondria or liver can increase the amount of lactic acid. Too much lactic acid can cause health problems.
• Normally, insulin carries sugar (glucose) to the cells to produce energy. When there is insulin resistance, less glucose reaches the cells and more stays in the blood.

There is no clear definition of lipodystrophy and therefore health care providers report that between 5% and 75% of patients taking ARVs experience some signs of this condition. Most researchers believe that approximately 50% of HIV sufferers experience lipodystrophy.

These changes were originally called "Crix belly" as they appeared in people taking the protease inhibitor Crixivan (indinavir). However, lipodystrophy can develop in people using any type of antiretroviral therapy (ART).

Is Lipodystrophy Dangerous?

Although it is not life threatening, lipodystrophy is a serious problem.

• High blood fat levels may increase the risk of heart disease.
• Lactic acidosis, although rare, can be fatal.
• Body shape changes can cause major upsets, to such an extreme that some patients stop taking their medications.
• Fear of developing body shape changes prevents may people from starting ART.
• Insulin resistance can lead to diabetes, weight gain and an increased risk of developing heart disease.
• Fat deposits at the back of the neck (buffalo hump) can get so big that they cause headaches, breathing and sleeping problems.
• Enlarged breasts in women can be painful.

No researcher has suggested that people with lipodystrophy should stop taking ART.

What Causes Lipodystrophy?

We do not know what causes lipodystrophy as its symptoms can be due to different causes.

One theory suggests that protease inhibitors (PI) interfere with the body’s processing of fat. PI molecules are similar to some human proteins that process and carry fat. However, some patients who have never taken PI also suffer from lipodystrophy.

Another theory suggests that insulin resistance plays an important role. People with insulin resistance tend to gain weight in the abdominal region.

Lipodystrophy is similar to "Syndrome X", which occurs in people who have recovered from a serious illness such as childhood leukemia or breast cancer. For HIV-infected people, it is possible that it is caused by recovery of the immune system following effective ART. In fact, lipodystrophy is more common in people who are getting good results from their ART.

One large study showed that several factors seem to increase the risk of developing lipo:

• Age of 40 or more
• Having AIDS for 3 years or more
• Minimum CD4 cell count below 100
• White race

Are There Any Treatments for Lipodystrophy?

As we do not know the cause, we do not know how to treat it. Body changes may worsen, stop or improve on their own.

Some people stop taking PIs to try and reverse lipodystrophy. Some changes in ART may improve certain signs of lipodystrophy. However, it takes a long time to reverse body shape changes.

Some fat deposits can be removed surgically or using liposuction. The only way to fill out sunken cheeks is via plastic surgery (implants or injections). This procedure carries risks and results may only be temporary.

Some benefits have been reported from changes in diet or exercise. Human growth hormone and testosterone may help with some symptoms of lipodystrophy and are currently being studied.

High levels of cholesterol and glucose must be treated in the same way as for people without HIV. Some health care providers prescribe drugs to reduce cholesterol and triglycerides or to improve insulin sensitivity.

Recently, a lot of attention has been paid to determining and reducing the risk of developing heart disease in people with HIV.

In Short

Lipodystrophy is a combination of changes in metabolism and body shape that occurs in people taking ARVs. There is no clear definition of lipodystrophy. It is hard to know exactly how many people have it. As we do not know the cause, we do not know how to treat it.

Researchers are studying hormone and other types of treatments. Stopping or replacing ART is not recommended.

Until more is known about the specific causes and treatment of lipodystrophy, its symptoms are treated in the same way as for the general population.

Terra