Learning How the Northern Elephant Seal’s Physiology Evolved
and Adapted to Withstand Certain Conditions Could Benefit Humans
MERCED, CA— Deprive a healthy, average-size
human of food and it’s likely he wouldn’t survive far beyond four
or five weeks. If that same person has sleep apnea, his body will
deteriorate even faster.
Northern elephant seal pups, however, live without eating for up
to three months and don’t appear to suffer any ill-effects. Sleep
apnea isn’t an issue for the adult animals either, because they go
as long as 11 minutes between breathes and that doesn’t appear to
harm their health.
Studying how the elephant seal’s physiology adapted and evolved
to allow them to endure prolonged fasting and episodes of sleep
apnea without suffering detrimental health consequences could help
scientists identify mechanisms that could someday help humans. That
is one of the primary focuses behind a new five-year $1.78 million
grant obtained by the University of California, Merced.
Rudy Ortiz, an assistant professor in the
School of Natural
Sciences, will serve as the primary investigator and oversee a
team of scientists from several universities and research
institutions. The grant’s sponsor is the National Heart, Lung and
Blood Institute, a division of the National Institutes of Health.
“The NIH is the primary source of funding in biomedical
research,” said Samuel Traina, vice chancellor for research and
graduate studies. “It is very competitive and typically hard for
assistant professors to get this money because they don’t have a
long-established track record that more senior faculty has. We
congratulate Professor Ortiz on this major accomplishment.”
“Rudy’s hard work and innovative ideas merit the recognition he
has received from the National Institutes of Health,” said Maria
Pallavicini, dean of the School of Natural Sciences. “We are
pleased for his success in obtaining this prestigious and highly
competitive award. His achievement illustrates the high caliber
research being completed by talented faculty at UC Merced.”
The project, “Mechanisms of Oxidative Stress and Inflammation
During Prolonged Fasting and Sleep Apnea,” has three specific
research objectives. First, investigators will analyze how elevated
amounts of the hormone, angiotensin II, contributes to oxidative
stress. Oxidative stress can, over time, impair how the body works.
Under normal conditions, angiotensin II helps regulate blood
pressure. However, inappropriately elevated levels of angiotensin
II can be detrimental, causing cardiovascular complications and inflammation.
“When those compounds — lipids, proteins and DNA —
get oxidized, it compromises cell integrity and they become
nonfunctional,” Ortiz said. “Those processes can impair the heart,
liver, kidneys and the other major organs of the body.”
The research team also will examine whether high levels of
cortisol contributes to oxidative stress. Cortisol, a steroid found
in all mammals, serves as an anti-inflammatory. When the body
produces too much, it can cause lean tissue to breakdown, resulting
in muscle deterioration. Northern elephant seals, however, burn
about 95 percent fat during their extended fasting period and are
able to conserve muscle tissue despite exhibiting elevated levels
of cortisol.
“The idea is to learn how they evolved to overcome those
deleterious effects,” Ortiz said. That segment of the research
could eventually lead to therapies to combat severe muscle
deterioration such as body wasting experienced by people with AIDS,
cancer or severe heart ailments.
The research team’s third objective is to study the
physiological reaction prompted by obstructive sleep apnea (OSA).
Sleep apnea is a disorder in which breathing repeatedly stops and
starts during sleep. The most common type, obstructive sleep apnea,
occurs when the throat muscles relax and blocks the airway. The
most noticeable sign of OSA is snoring.
In humans, untreated OSA can lead to serious health
complications such as congestive heart failure. Elephant seals,
however, do not appear to suffer apnea-related health
complications, despite taking only four to six breaths per hour
while asleep.
“No other group of mammals can do that. That is why they are
such a great model to study,” Ortiz said. “The idea behind our
research is to reveal the mechanisms they have developed to help us
better address questions in human medicine.”
Ortiz’s research team includes biochemistry and chemistry
professor
Henry
Forman, a founding faculty member at UC Merced; Daniel E.
Crocker, associate professor of biology at Sonoma State University;
Tania Zenteno-Savin, an associate researcher at the Centro de
Investigaciones Biologicas del Noreste (CIBNOR) in La Paz, Mexico;
C. Leo Ortiz, a professor emeritus of biology at UC Santa Cruz;
Bruce Freeman, chairman of pharmacology at the University of
Pittsburgh; Dave Casper, the attending veterinarian at UC Santa
Cruz and pharmacology professor Jack Roberts of the Vanderbilt
University School of Medicine.
