Progress in four specific areas is profiled below, each of which is a NASA “Health and Human Performance Risk for Space Exploration”.8 All demonstrate linkages between basic and applied research and involve on-going collaborations between Space Biology and the HRP. These examples illustrate ongoing opportunities for synergy between basic and applied researchers and these NASA programs to enhance and accelerate health-risk reduction.
The immune system is constantly adapting and is particularly responsive to unique environments such as those in spaceflight, especially for exposures of the long durations required by exploration missions beyond LEO. Immune system dysregulation (decreased responsiveness) has been seen during and after spaceflight and ground-space analog tests by studying humans,54 animals,55 and relevant cell cultures56 and are a priority area for study (AH13-15, Table 1). The specific causes are not yet clear, but are likely linked to one or more of the following factors: physiological stress, circadian rhythm disruption, microgravity exposure, isolation, altered nutrition, or radiation exposure.57 Further, the spaceflight environment compounds crew health risks as some microorganisms become more virulent (see below) and resistant to antibiotic drugs.
Even though the reactivation of latent viruses has been well documented in crewmembers,58 it is still unclear if the compromised immune response can lead to increased susceptibility to disease. There is not a sufficiently accurate ground-based analog to study immune suppression from spaceflight. However, extreme occupational environments such as Antarctica winter-over and the Aquarius undersea station enable aspects of immune dysregulation to be studied under similar stressors. Additionally, many valuable analog studies with animals and cells have been conducted, including unloading of rodents,59 and cell cultures and bioreactors.56,60 These studies have investigated immune response mechanisms and can allow the use of controlled diets, increased radiation levels and other factors that are not possible in human research.
Preventive measures limit the presence of many medically significant microorganisms during spaceflight missions, but microbial infection of crewmembers cannot be completely prevented. Spaceflight experiments have demonstrated unique and heterogeneous microbial responses in spaceflight ecosystems and cultures,61,62 although the mechanisms behind those responses and their operational relevance remain unclear. In 2007, the operational importance of these microbial responses increased, as the results of Space Biology experiments aboard STS-115 and STS-123 demonstrated that an enteric pathogen (Salmonella typhimurium) increased in virulence in a mouse model of infection,63,64 responding to recommendation AH15 (Table 1). These studies can improve our understanding of the potential consequences to astronauts of elevated microbial virulence during long-duration missions.
Evidence for increased microbial virulence has recently been collected and reported from both spaceflight-analog systems and actual spaceflight.61,65,66 Although the conduct of virulence studies during spaceflight is challenging and often impractical in humans, data are being collected as part of the ISS Microbial Observatory,62 recent astronaut and rodent microbiome studies,67,68,69 and the edible plant studies (e.g., Veggie).70,71 When available, these results can improve our understanding of the astronaut-microbe interaction and of the potential health risks to the astronaut.
The novel environmental conditions of spaceflight, and their combination, may affect both the generation and safe processing of reactive oxygen or nitrogen species.72,73 Evidence for oxidative-related issues in astronauts (or their analogs) can be found in the HRP Evidence Reports covering inadequate nutrition,74 extravehicular activity,75 and exposure to ionizing radiation.47,76,77,78,79 NASA has successfully used horizontally-integrated team science to understand and mitigate components of radiation-induced oxidative stress42,43,44 in mice.
Visual impairment/intracranial pressure (VI/IP)
During and after long-duration spaceflights, some astronauts have reported noticeable, persistent VIs accompanied by ophthalmic changes including globe flattening, choroidal folds, optic-disc edema, and optic-nerve kinking.80 To date, clinically significant changes have been observed in male, but not female, astronauts,81 identifying a not yet understood sex difference, CC10 (Table 2). Increased intracranial pressure and optic-disc swelling (papilledema) may underlie these potentially irreversible changes.81 Current research is analyzing the effects of lowering cranial hypertension by using lower body negative pressure in astronauts during flight and bedrest,82 supporting the CC2 goal (Table 2).
Clinical signs and symptoms observed in astronauts have informed and focused important mechanistic studies exemplifying reciprocal translation at NASA (i.e., applied to basic). For example, retinas of female mice flown on the shuttle (STS-133, STS-135), acquired by the BioSpecimen Sharing Program, exhibit altered gene expression and increased oxidative stress,83 possibly causing retinal damage, degeneration, or remodeling.84,85 Other basic research is examining morphological, histological, and molecular changes in the brains and eyes of rats exposed to head-down tilt.86
Altogether, these examples are in the early stages of mechanistic understanding and countermeasure development. Already each has benefited from translational approaches. We suggest that a more coordinated programmatic effort of horizontal and vertical integration will accelerate countermeasure development. In the closing section, we provide suggestions of how enhanced translational research could materialize at NASA.
Photo courtesy of NASA
By: Keith Ferrell
American scientists now have an out-of-this-world platform from which to conduct groundbreaking health and medical research. A recent agreement between NIH and NASA provides the basis for a U.S. national laboratory on the International Space Station.
Even as you read these words, there's a world of research going on high over our heads—approximately 200–215 miles up. The International Space Station (ISS), which has been taking shape for much of the past decade, is an orbiting laboratory for many kinds of research.
This past September, the National Institutes of Health (NIH) and the National Aeronautics and Space Administration (NASA) established a formal understanding that will make medical and health research an important ongoing part of ISS research activities. This new relationship between the nation's premier medical laboratories and the national space effort is a first, and already there is much excitement about the various advances to come from space-based research.
"There are many new frontiers and considerable new knowledge that medical researchers can gain from using the space station," says Stephen I. Katz, M.D., Ph.D., director of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) and NIH's liaison with NASA.
A Unique Laboratory
Continuously inhabited by astronauts and scientists since 2000, the ISS is a perfect place to research all manner of scientific, technical, and medical questions. In fact, some medical research can only be performed in orbit. That means aboard the space station, where there is no gravity. The same weightlessness that lets space-suited astronauts move massive objects easily also offers a unique learning opportunity.
Zero-gravity's effects on astronauts' skeletal systems and loss of bone and muscle mass have long attracted scientific interest, Dr. Katz says. "Research on the space station will help generate better understanding of how weightlessness affects the bone, muscle, and inner ear systems."
The more we know about how the various systems of the human body react to weightlessness and the other conditions found only in space, the better able we will be to ensure the health of ISS crew members, as well as those future astronauts and researchers who will journey to the moon (again), Mars, and beyond.
The benefits also will pay off back on earth:
- Increased understanding of bone-strength and loss of bone-mass may help patients suffering from delicate bones or musclewasting diseases.
- Without gravity to help orient them, astronauts experience changes in their sense of balance. Studying this phenomenon may yield insights into dizziness, vertigo, and balance problems and disorders related to the inner ear.
- Observing the behavior of microbes and other organisms in space can generate insights into the behavior of organisms on earth, and perhaps lead to better understanding of infectious diseases and the immune system's response to them.
Our health and medical knowledge and capabilities have grown greatly because of space exploration and the equipment and techniques developed for it. Remote health-monitoring sensors and temperature-lowering "cool suits" are just two examples derived from the lessons learned from orbital space suits. And medical imaging technologies and ultrasound procedures are based, in part, on NASA innovations.
NIH Director Dr. Elias A. Zerhouni and NASA Administrator Dr. Michael D. Griffin sign an agreement making U.S. resources on the International Space Station available for NIH-funded research. Senator Kay Bailey Hutchison (left), Senator Barbara Mikulski and NIAMS Director Dr. Stephen I. Katz witness the occasion.
Photo courtesy of NIH
Long-Term Space Research
Until the advent of the ISS, research missions in space were necessarily brief—usually only a few days or weeks, at best. With long-term human residence in space now made possible by the ISS, it is important that a certain percentage of each ISS crew be dedicated to vital medical research. As with everything connected with space travel, results will take time because of the planning, preparation, and training involved.
"An enormous amount of time will be required to develop the questions and experimental models for use on the space station," says Dr. Katz. "First, you have to make sure you're asking important questions. Also, the scientists' time is valuable, and it's very expensive to put the experiments together and transport them to the space station." Added to this is additional training the astronauts—many of whom are scientists —must complete to be able to perform the experiments correctly. Thanks to the formal agreement between NIH and NASA, the research will be carefully coordinated into high-priority areas, with promise of practical results.
"Both NIH and NASA are committed to real cooperation," Dr. Katz says.
This cooperation may serve as the foundation for a potential flowering of both space medicine and earth-based health care.
"We are extremely pleased that this collaborative effort is moving forward," adds NIH Director Dr. Elias Zerhouni. "The International Space Station provides a unique environment where researchers can explore fundamental questions about human health issues, including how the body heals itself, fights infection, or develops diseases such as cancer or osteoporosis."
Research projects on the ISS funded by the NIH will be conducted on the U.S. segment of the space station and be consistent with existing NIH priorities and relevant to improving human health on earth.
Dr. Michael Griffin, NASA administrator, adds enthusiastically, "Not only will the station help to explore the moon, Mars, and beyond, its resources also will be applied to the much broader purpose of improving human health."
Inspired by the space suits Apollo astronauts wore to survive the moon's harsh climate, the Recharge™ Active Cooling System by Cool Systems Inc. helps patients with multiple sclerosis and heat-related neurological disorders manage their symptoms by lowering their core body temperature.
Photo courtesy of NASA
DIGITAL IMAGING BREAST BIOPSY SYSTEM— A non-surgical system developed with Space Telescope Technology that greatly reduces the time, cost, pain, and other effects associated with traditional surgical biopsies.
BREAST CANCER DETECTION—A solar cell sensor that determines exactly when x-ray film has been exposed to optimum density; it reduces exposure to radiation and doubles the number of patient exams per machine.
LASER ANGIOPLASTY—A "cool" type of laser, called an excimer laser, which offers precise non-surgical cleanings of clogged arteries and fewer complications than in balloon angioplasty.
ULTRASOUND SKIN DAMAGE ASESMENT—An advanced ultrasound instrument to immediately assess depth of damage, improving patient treatment and saving lives in serious burn cases.
HUMAN TISSUE STIMULATOR—A device employing NASA satellite technology that is implanted in the body to help control chronic pain and involuntary motion disorders through electrical stimulation of targeted nerve centers or particular areas of the brain.
COOL SUIT—Custom-made suit that circulates coolant to lower body temperature; it dramatically improves symptoms of multiple sclerosis, cerebral palsy, spina bifida, and other conditions.
PROGRAMMABLE PACEMAKER—An implant connected to a physician's computer and used to regulate heart rate, incorporating multiple NASA technologies.
OCULAR SCRENING—An image-processing technique developed by NASA and now used to detect eye problems in very young children.
VOICE-CONTROLLED WHEELCHAIR—Robotic wheelchair manipulator that responds to 35 one-word voice commands, helping patients to perform daily tasks like picking up packages, opening doors, and turning on appliances.
WATER PURIFICATION SYSTEM—A municipal water treatment system for developing nations that uses iodine instead of chlorine to kill harmful bacteria.
Fall 2007 Issue: Volume 2 Number 4 Pages 4 - 7