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USC hematologist seeks causes, potential cures for bone death

Imagine tiny cracks developing in your hip or your knee–growing slowly, but often painfully, over a long period until the joint simply collapses.
It is called osteonecrosis, a condition responsible for some 50,000 hip surgeries every year. And it’s a problem under investigation by Howard Liebman, associate professor of medicine and pathology in the division of hematology, with the help of a new two-year, $115,000 grant from the William and Virginia Hayden Foundation.

Tens of thousands of people are diagnosed with new cases of osteonecrosis every year, with most of them between ages 30 and 50, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases.

“Osteonecrosis is a major problem,” Liebman said. “It may lead to problems in being able to walk, and results in painful, destructive joint lesions.”
Why would a hematologist be looking at bone weakness? Because the health of bones closely depends on the blood supplied to them.

Liebman specializes in bleeding and clotting disorders. One of the diseases he has investigated is Gaucher’s disease, an inherited disorder of lipid storage that may be associated with bleeding problems. Besides problems with bleeding, patients with Gaucher’s disease experience enlarged livers and spleens, anemia, reduced platelets, and bone problems such as osteoporosis.
Recently, Liebman and a colleague presented a study at the American Society of Hematology showing that an activation of low-grade clotting in such patients may directly lead to osteonecrosis.

Now, with the collaboration of Edward McPherson, assistant professor of orthopaedic surgery, and rheumatologist Daniel Arkfeld, assistant professor of medicine, Liebman will look at the activation of clotting systems outside of Gaucher’s disease, and how the clotting problems contribute to osteonecrosis in other patients.
Although it can happen in any bone, osteonecrosis most commonly affects the ends of long bones such as the femur, the bone extending from the knee joint to the hip joint.
Sometimes the disease affects just one bone, but it may also damage more than one bone at the same time-or several bones at different times.

This bone death can be traced to several causes, such as the long-term use of corticosteroids (taken for lupus, organ transplants, asthma and several other conditions), excessive alcohol consumption, trauma to bones, sickle cell disease, pancreatic problems and “the bends” a condition brought on by a rapid reduction of air pressure in scuba diving.
But some cases are of an unknown cause.
Because many gene markers have now been identified as linked to the human body’s capacity for blood clotting, Liebman said, researchers may now be able to better determine those defects that also are tied to osteonecrosis. That may help remove some of the mystery surrounding the disease.

USC hematologist seeks causes, potential cures for bone death

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