Fw: News release from UT Southwestern March 20, 2001

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----- Original Message -----

From: " Robin Amerine " <Robin.Amerine@...>

<UTSWNEWS@...>

Sent: Tuesday, March 20, 2001 4:47 PM

Subject: News release from UT Southwestern March 20, 2001

Media Contact: Hill

214-648-3404

amanda.hill@...

UT SOUTHWESTERN RECEIVES GRANT TO STUDY LOWERING RISKS FOR BONE LOSS, KIDNEY

STONES DURING SPACE MISSIONS

DALLAS - March 21, 2001 - The next major project for the National

Aeronautics and Space Administration is the Mission to Mars.

Although some people may still think of this frontier of space exploration

as simply science fiction, it may become a reality based on the results of

newly funded research projects that include a bone-loss, kidney-stone study

at UT Southwestern Medical Center at Dallas.

The National Space Biomedical Research Institute in Houston recently funded

86 projects nationwide that included a three-year, $456,000 grant to

evaluate the effectiveness of a drug, which was developed by UT Southwestern

researchers, as a potential countermeasure to the adverse effects of

weightlessness on both kidney-stone formation and bone loss.

The team of investigators will include Dr. ph Zerwekh, professor of

internal medicine and principal investigator; Dr. Pak, chief of the

Division of Mineral Metabolism; Dr. Antich, professor of radiology,

and Dr. Wuermser, assistant professor in physical medicine and

rehabilitation.

" To overcome the challenges of a long-term space mission, we must have

effective countermeasures in place that can prevent or lessen the negative

impact exerted by microgravity on normal physiological processes, " said

Zerwekh.

" A Mars mission would last no fewer than 2 ½ years. It would take

approximately six months to travel there, six months to travel back, and a

year and a half on Mars, waiting for the proper cyclical orbit so that the

shuttle could return, " Zerwekh said.

Previous studies from Gemini, Apollo, the space station, and shuttle

missions have clearly pointed to an increased risk for kidney-stone

formation, as well as bone loss, for astronauts in a weightlessness

environment.

Zerwekh said a number of changes occur in the composition of the urine that

increase the risk for stone formation. Both urinary calcium and phosphorus

increase, due to increased bone destruction and, thereby, make the urine

more concentrated with respect to these stone forming salts. In addition,

there are metabolic changes that result in a more acidic urine being

excreted that contains less citrate, a potent inhibitor of kidney-stone

precipitation and growth. All of these observed changes significantly

increase the risk for kidney-stone formation, he said.

Researchers will look at the effects of Relyte, a formulation of

potassium-magnesium citrate, to see whether or not taking it reduces the

risk of kidney-stone formation. Relyte is in the clinical trials phase of

the Food and Drug Administration's approval process, and is a product that

was developed by Pak's team of researchers.

Previous studies have also documented a significant loss of bone mineral

during space flight and during prolonged immobilization on Earth. An

increase in the acid content of the diet contributes to the bone loss, and

diets consumed by astronauts during space missions tend to be acidic in

nature.

The use of Relyte, which would increase alkali intake, may reduce the

acid-mediated loss of bone mineral in addition to its effect in reducing

kidney-stone formation, Zerwekh said.

Researchers will examine 20 normal subjects at total bed rest for five

weeks, an Earth-based model that mimics the skeletal unloading, or

weightlessness, encountered in space.

Volunteers will not be allowed to get out of bed or to sit up but will be

allowed to prop themselves up on one arm to eat or read. Zerwekh said

one-half of the subjects will receive Relyte, and the remaining half will

serve as the placebo control.

Patients will maintain a regimented diet prior to the collection of urine

and blood samples for determination of stone-risk factors and the extent of

skeletal bone-mineral loss. They will also receive an ultrasound bone scan

to determine whether or not their bones are weakening.

Once the five-week in-patient portion of the study is completed,

participants will undergo outpatient monitoring for two additional weeks.

##

This news release is available on our World Wide Web home page at

http://www.utsouthwestern.edu/home_pages/news/