Medicine Reaps the Benefits of Manned Space Flight
Cover Story -- May 2003
By Ken Ortolon
Physicians across America perform hundreds of electrocardiograms (ECGs) every day. But few of them probably stop to think about the origin of that technology. The ECG electrodes were developed for monitoring astronauts in space.
A generation ago, Americans were fascinated with space exploration and the technological advances it brought. We sat glued to our TV sets when men walked on the moon. Today, we hardly notice when men and women venture into space, until disaster strikes as it did in February when the space shuttle Columbia was lost in a fiery explosion during reentry, killing all seven astronauts on board, including two physicians, U.S. Navy Capt. David M. Brown, MD, and Cmdr. Laurel Clark, MD.
The Columbia disaster refocused America's attention on the space program and the benefits we here on Earth derive from it. Some wonder whether manned space flight continues to be necessary, whether the rewards reaped from our shuttle missions and the International Space Station are worth the risk to human life.
The answer is definitely yes, according to physicians and scientists at the National Aeronautics and Space Administration (NASA) and those doing research with NASA, many of them based at Texas universities and medical schools.
"When tragedies like Columbia and Challenger happen, I think it's healthy to take a look and ask if what we're doing is worth the risk," said former astronaut Bernard Harris, MD. "I think we're all doing some soul-searching right now."
But Dr. Harris, who flew on Columbia in the 1990s, says space exploration has pushed the boundaries of science, including medicine, and manned space flight is necessary if scientific frontiers are to be explored.
"If you ask me whether we have gotten any benefit out of space exploration, I know the answer is an unequivocal yes," he said. "Is it important that we continue to do it? Yes, it is. Is it worth the risk that we take as human beings by going into space flight to benefit us here on Earth? The answer again is yes."
The Spin-Off Spin
From the earliest days of the space program, technologies developed for use in space have found useful applications on Earth. (See " Big Returns From Space Investments .")
Some NASA critics say the human benefits derived from space exploration have been overblown. In a 1993 column published by the American Physical Society, writer Robert L. Pack cited a report written by NASA itself concluding that "there have not been many technology transfer successes compared to the potential."
But physicians and scientists say the list of technologies and scientific advances that have spun off the space program or resulted directly from space-based research is a long one. These advances have changed our way of life on Earth and revolutionized some areas of medicine, says Richard Jennings, MD, former chief of flight medicine at NASA's Johnson Space Center in Houston and director of the Aerospace Residency Program at The University of Texas Medical Branch in Galveston.
"When I get up in the morning to fly my airplane, I put on glasses with UV coating that was developed for the Apollo program," said Dr. Jennings. "The frames are made from metal that was designed for the space program to be able to flex and bend and change temperature without breaking."
Satellites launched by NASA make possible many of the things we do every day and take for granted, such as watching television, using pagers and cellular phones, even paying for gasoline at the pump with a credit card.
"It's not much different in medicine," Dr. Jennings said. "There's no question that a lot of direct changes to medicine have come from space technology."
Jim Logan, MD, manager of medical informatics and health care systems at the Johnson Space Center, says one such technology is computerized and digital radiography, pioneered by NASA in an attempt to discover x-ray sources in the universe.
"Computerized and digital radiography has really revolutionized standard radiology here in this country," Dr. Logan said. "So we have a technology that was first looked at in space but is now used on a daily basis by tens of thousands of people."
Another example is remote sensing, which was developed, among other things, to look back at Earth from space, he says. With adequate resolution, remote sensing can allow astronauts hundreds of miles in space to pick out an individual diseased tree in a forest. That same technology is now being applied to picking out diseased cells within the human body.
For instance, if a woman has an abnormal Pap smear, physicians typically take a cervical biopsy using dye to help identify abnormal cells. "Now, there's technology available so that, in essence, we're using hyperspectral imaging of the cervix. It's remote sensing applied in a micro situation instead of a macro situation."
Pumping It Out
At Baylor College of Medicine in Houston, Michael E. DeBakey, MD, and George Noon, MD, have been working for nearly 15 years to develop a new kind of heart pump to help patients whose own hearts cannot circulate an adequate blood supply. The left ventricular assist device (VAD) was developed from technology first used to pump fluids, such as fuel, in space.
Dr. Noon, professor of surgery and head of the Division of Transplantation and Assist Devices in the Michael E. DeBakey Department of Surgery at Baylor, says he first met with NASA engineers to discuss the idea in 1988. The device was not ready for clinical trials until 1998.
Since that time, the VAD has been implanted in 30 patients in the United States, including 22 at Baylor, and nearly 150 in Europe. While artificial hearts and other assist devices pump blood by pulsating, just as the heart does, the VAD can pulsate or produce a steady flow of blood with no pulsation.
Dr. Noon says the VAD's effectiveness is similar to other devices currently in use but it benefits both the physician and the patient. "From the surgical standpoint, we like it because it's much easier to implant and it's also much easier to explant because it's so much smaller. And, the patients like it because it doesn't make any noise compared with other pumps, and it's much smaller so they're less aware they have it."
Clinical trials have been performed to demonstrate the VAD's role as a "bridge to transplantation," Dr. Noon says. The device is implanted in patients on the heart transplant waiting list whose hearts need assistance if they are to survive until a heart is available. When a new heart is found, the device is removed.
While it has not been tested as a "bridge to recovery," Dr. Noon says a few patients have recovered while on the device, making a transplant unnecessary. Eventually, the device will be tested as a permanent implant to assist weakened hearts.
The VAD already has been approved for commercial use in Europe, but Dr. Noon says it likely will be another two to three years before it gets U.S. Food and Drug Administration approval for widespread use here.
Medical application of technology developed for space flight, however, is only part of the benefit that medicine derives from the space program. NASA works with hundreds of researchers across America to conduct ground- and space-based research, ranging from studying bone loss and circulatory problems associated with long-duration space flight to growing tumor tissues for cancer research.
Dr. Harris says that more than 90 investigations were completed on board his first shuttle mission a decade ago, more than half involving human science. On Columbia's final mission, more than 80 experiments were being conducted. (See " Science Lost .") While data from some of these experiments were down-linked during the flight, much of the results and all of the research materials were lost.
"Not only was a lot of data lost, we also lost a brand new lab. That's a significant setback," Dr. Logan said." The new SPACEHAB research module significantly increased the amount and complexity of research that was possible on the shuttle. "This was its first flight and it was designed to be reusable," he said.
Also among the research lost on Columbia was an investigation by Emory University scientists of the role bone marrow plays in helping prostate cancer cells metastasize. Neil Pellis, PhD, NASA program scientist for the International Space Station, says the experiment used a bioreactor to grow prostate cancer cells alongside structural cells from bone marrow called stroma.
"For some reason, bone is a very, very high probability target for metastasizing prostate cancer," Dr. Pellis said. "Their hypothesis is that the stroma or the bone marrow actually changes a specific property in the cancer cell that makes it refractory. They wanted to look at that relationship."
The bioreactor was developed to create three-dimensional cell cultures. Dr. Pellis says that when you grow cell cultures in a Petri dish, the tissue can reach only a certain size before gravity forces it to the bottom of the dish, where it tends to flatten out in a thin layer.
The bioreactor is a small tube filled with fluid culture medium and then rotated. The fluid rotates at the same speed as the cylinder, keeping the cell culture in constant suspension, allowing it to grow into multilayered tissue. On the ground, a bioreactor can produce tissue samples up to about one-half inch in length. In space, scientists can grow samples twice that size or more.
One Texas-based experiment on Columbia used rats to look at the effects of microgravity on blood vessels and the regulation of arterial blood pressure. Michael Delp, PhD, professor of health and kinesiology at Texas A&M University, says that experiment was a total loss because researchers were not able to examine the rodents after the flight.
"When humans come back from space, a large number of them are not able to stand for 10 minutes," Dr. Delp said. "Our studies were designed with animals to understand why that is and to understand what's happening, particularly to the heart and blood vessels, that makes the cardiovascular system unable to withstand the stress of gravity."
While the experiment was intended to help man survive long-duration space flight, it also had applications in the study of aging, Dr. Delp says. "Older individuals also have problems maintaining blood pressure. When you stand up too quickly, you get a little lightheaded and fuzzy. Older people often will pass out. If they pass out and fall, they might break a hip or wrist. There are a lot of common characteristics between that and what the astronauts undergo."
While much data were lost aboard Columbia, the grounding of the shuttle fleet pending the investigation into the cause of the crash will further delay space-based research. Ground-based investigations are continuing, but any experiments requiring microgravity are on hold until the shuttle is cleared to fly again.
"When we're not flying, we're not doing microgravity research," Dr. Pellis said. "For the biomedical sciences and life sciences, there are limited other venues in which to do this."
James Thomas, MD, chair of cardiovascular imaging at the Cleveland Clinic Foundation, says grounding the shuttle fleet also will hamper research on the International Space Station, primarily because the space station crew is being reduced from three to two for the foreseeable future.
"We were already hampered by the fact that only three crew members are up there," said Dr. Thomas, who has researched real-time transmission of echocardiographic images from space. "The hope was that eventually we would get to a six- or seven-person crew. That is certainly going to be delayed by whatever time the shuttle is delayed."
The disaster also could have a tremendous impact on how many manned space missions NASA mounts in the future. Following the Challenger disaster in 1986, NASA stopped using the shuttle to launch satellites and switched back to unmanned, expendable rockets, Dr. Jennings says. He believes the space shuttle's role may be further cut to carrying astronauts to and from the space station, with the space station becoming the primary base for space research.
Send in the Robots
Others argue that manned flights are not always necessary for conducting research. But Dr. Pellis says they are vital because robots and computers can't do everything humans can.
"You can't do this all with robotics," he said. "If that were true then they could just make a robot for me and send him into the lab. We can program them to do anything, but human eyes and sense for seeing what's taking place and making real-time observations and decisions are what bring us to the discoveries we seek."
Dr. Harris agrees. "I think that robots can do some things well, and for those things let's let the robots do them. But if you're going into unknown territory and you're not quite sure what sort of actions and reactions you're going to get, the best computer is the human mind. It is able to handle different situations. It is able to think real time. It does not require messages to be sent back to be examined by human beings on earth. If you're going to explore space effectively and do scientific investigations, you've got to have a dialog that you don't get when you involve automated systems."
When the shuttle will fly again is anybody's guess, but Dr. Harris says he would not hesitate to ride it into space again. Dr. Thomas says he suspects most of the current astronaut corps feels the same way.
"Certainly, before we put anybody else's life at risk we need to find out what happened, and we need to correct as much as humanly possible," Dr. Harris said. "But you can only do so much. As astronauts, we understand that, we understand that there's a risk. There has always been risk in traveling in space."
Dr. Jennings says space flight always will have risks, no matter how hard scientists and engineers work to make it safe. "I don't think you can take people from zero to 17,500 miles per hour and get rid of all of the risk," he said. "It's tragic when people are killed in accidents, but I don't think this will stop the march to space anymore than deaths among people in wagon trains stopped their westward expansion and the settling of the United States."
But with those risks come the chance for great reward, says Dr. Pellis. "Because of the nature of space exploration, almost everything we do pushes way onto the edge of what our technological capabilities are. There's no question about it; we take everything to its absolute extreme and beyond. When you do this, the result is technological advancement that can be revolutionary."
Ken Ortolon can be reached at (800) 880-1300, ext. 1392, or (512) 370-1392; or by email at Ken Ortolon.
Big Returns From Space Investments
What has the space program done for you lately? According to National Aeronautics and Space Administration (NASA) researchers, plenty.
One of the newest medical spin-offs from space exploration is a nonsurgical breast biopsy technique using technology developed for the Hubble Space Telescope. The technique, called stereotactic automated large-core needle biopsy, enables a doctor to precisely locate a suspicious lump and use a needle instead of surgery to remove tissue for study.
The process is possible because of a key improvement in digital imaging technology known as a charged coupled device, or CCD.
Some other medically related breakthroughs resulting from the space program include:
- A laser system first used for satellite-based atmospheric studies has been reapplied to treat arteriosclerosis. Developed by Advanced Interventional Systems, Inc., (AIS) in Irvine, Calif., and approved by the U.S. Food and Drug Administration in 1992, the DymerTM 200+ excimer laser angioplasty system vaporizes blockages in coronary arteries without damaging arterial walls.
- A state-of-the-art implantable pacemaker uses communications technology developed by NASA to communicate with satellites. Bidirectional telemetry, a type of two-way communications, allows physicians to send signals to the pacemaker to alter its rate and also receive return signals on how it is interacting with the heart. The doctor can adjust the device to best suit a patient's needs, which may change over time.
- An ingestible thermometer capable of accurately measuring and relaying deep internal body temperatures improves patient care in hospitals and offers opportunities in medical experimentation. Developed by the Johns Hopkins University Applied Physics Information Laboratory in collaboration with NASA's Goddard Space Flight Center, the three-quarter-inch silicone capsule contains a telemetry system, a micro-battery, and a quartz crystal temperature sensor. The sensor reads the internal temperature and telemeters the information to a receiving coil outside the body. From there it is relayed to a computer. The "temperature pill" monitors continuously during the 24 to 78 hours it takes the capsule to travel through the digestive system. The pill can record a patient's temperature every 30 seconds and can be programmed to sound an alarm if the temperature exceeds preset limits. Researchers developed the device for treating such emergency conditions as hypothermia and hyperthermia.
- The application of NASA ultrasound technology, originally developed to detect microscopic flaws in aircraft and spacecraft materials, has provided an advanced instrument that enables immediate assessment of burn damage. This knowledge improves patient treatment and may save lives in serious burn cases.
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Scientific research aboard the final flight of space shuttle Columbia was designed to be a bridge between research conducted aboard the shuttle in the 1980s and 1990s and the long-term work planned for the International Space Station when it is completed.
Some 80 investigations on such varied topics as fireballs, kidney stones, tumor growth, and sponge-like rocks were conducted. Below are some of the medically related experiments that were onboard:
- Several experiments sponsored by the European Space Agency used an advanced respiratory monitoring system to study the impact of weightlessness on the heart, lungs, and metabolism.
- French scientists had rats aboard Columbia for the purpose of studying how space impacts fluid balance in the brain and regulation of body fluid production.
- To better understand how and why weightlessness induces bone loss, Columbia astronauts were participating in a study of how calcium moves through the body, including absorption from food, and its role in the formation and breakdown of bone.
- An experiment to help astronauts fight bacterial and viral diseases in space was to have examined how certain cells in the astronauts' innate immunity system functioned before and after flight.
- To protect astronauts from developing kidney stones in space, NASA scientists were studying the use of potassium citrate to reduce the risk of stone formation.
- Emory University scientists were using a bioreactor to grow three-dimensional prostate cancer cells to support studies of cell interaction between prostate and bone stromal cells. The results would have aided scientists in assessing the effect of gene therapy on the growth of prostate cancer cells.
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