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Research Briefs
Research Unit Goes to Extremes
Researchers from Mayo Clinic have been studying the effects of altitude illness by examining workers who travel from McMurdo Station in Antarctica (sea level) to the South Pole (high altitude). Bruce Johnson, who heads the research study, is holding the bottom right corner of the flag. Photo courtesy of Mayo Clinic.
Each year when summer comes to the southern hemisphere, hundreds of researchers and support staff descend on the South Pole. And every year, despite careful health screening, a few researchers may need to be evacuated because of severe altitude illness, and scores more may experience milder symptoms, such as headache, nausea, dizziness, shortness of breath, and fatigue.
For the past two years, Bruce Johnson has journeyed here from Rochester, Minn., where he is a professor of medicine at Mayo Clinic’s College of Medicine, to study altitude illness and to find genetic markers that may predict predisposition to this ailment. On Johnson’s latest expedition to the South Pole in fall 2007, phlebotomist Josh Mueller accompanied the team. Mueller was on loan from Mayo’s innovative “mobile” clinical research unit, established in 2007 with funding from an NCRR Clinical and Translational Science Award (CTSA) to the Mayo Clinic College of Medicine.
The Antarctic Study of Altitude Physiology, headed by Johnson, is a three-year project funded by a research grant from the National Science Foundation. The study has broad implications for human health, because the biological processes at work in severe altitude illness also underlie other serious health conditions, such as congestive heart failure and chronic lung disease. The study may also advance understanding of how people adapt to low pressure, such as in space flight, and thus has prompted interest from NASA.
Unquestionably, the Antarctic Study poses unusual logistical challenges. To reach their study subjects, Johnson’s team must fly for 24 hours to Christchurch, New Zealand, then six more hours to McMurdo Station in Antarctica, and then another three hours, when weather permits, to reach the South Pole. (On two occasions, bad weather grounded the team at McMurdo for two weeks.) After examining South Pole workers at the main station, Johnson and colleagues must then hike a half-mile in bone-piercing cold and wind to tents housing seasonal residents.
Although the South Pole sits at 9,300 feet above sea level, the Earth’s spin and the cold create atypically low pressure that approximates up to 11,000 feet or higher. This pressure causes hypoxemia, or reduced levels of oxygen in the bloodstream, which is the root cause of the symptoms of altitude illness. Thus, Johnson’s team collects blood samples from study participants and, with the aid of monitoring devices, gathers data about numerous physiological functions over time, hoping that the numbers will provide a picture of the mechanisms of illness.
Back at the lab at Mayo Clinic, Johnson, who also co-directs the CTSA-funded Energy Balance Core of Mayo’s Center for Translational Science Activities, processes the blood samples, totaling about 16 per subject, for biochemical assays and gene expression. “Without CTSA support, we’d be looking for ways to cut corners a little bit in recruiting subjects and processing samples,” says Johnson.
So far, Johnson has collected and analyzed samples from approximately 240 subjects at sea level (McMurdo Station) and from about 200 people at high altitude (the South Pole). His ultimate goal is to test 300 subjects at each site by the end of the study.
The mobile clinical research unit that facilitated Johnson’s most recent polar expedition is one of three CTSA-supported clinical research units at Mayo. The other two are stationary units located in Mayo’s two Rochester hospitals, supporting both inpatient and outpatient studies. Typically, hospital medical staff are too busy caring for patients to assist researchers with their studies. However, the more than 100 specially trained staff dedicated exclusively to the clinical research unit provide Mayo investigators with valuable help in collecting blood and other samples from patients, administering study drugs, monitoring physiological responses, and recording study data.
The mobile unit, which averages a staff of seven registered nurses and technicians, extends the reach of Mayo’s clinical studies. “The mobile clinical research unit opens up whole new avenues of research, because it allows people of all ages and states of health to participate in clinical studies regardless of where they are,” says Andrew Badley, its director and a professor of medicine at Mayo.
The South Pole is the farthest afield the mobile unit has ventured thus far. Closer to home, current studies have taken the unit to Mayo’s operating rooms for research on heart valve surgery, to Winona State University for a genetics study in healthy student volunteers, and to Minneapolis for a “real-world” obesity study involving exercise interventions in the workplace. Badley reports that his unit is currently conducting “a significant number of studies off campus, and we expect its use to increase.”
–Barbara Shapiro
NCRR Resources: The Mayo Clinic College of Medicine is a member of a national consortium, funded through the Clinical and Translational Science Awards program, that is transforming how clinical and translational research is conducted, ultimately enabling researchers to provide new treatments more efficiently and quickly to patients. For more information, visit CTSAweb.org.
