Previous Page 3 of 4 Next

Continued: Can dormant bears help us heal?

  • Article by: BILL MCAULIFFE , Star Tribune
  • Last update: December 26, 2009 - 11:26 PM

CAMP RIPLEY, MINN. - For two winters now, a mother bear has been denning on George Vilinski's land. A few tracks last spring are the only signs he has seen.

"She's like a ghost," he said.

But researchers are hoping this bear and others around the state will reveal some mysteries about hibernation -- and how it might be used to help humans.

"It could have a lot of positive benefits if we find out what these bears are doing," said Paul Iaizzo, a surgery professor and principal investigator at the University of Minnesota's Visible Heart lab.

Recently Iaizzo and a team of researchers from the University of Minnesota, Medtronic and the Department of Natural Resources visited the bear on Vilinski's land, and others in northern and northwestern Minnesota, to see what they might be able to detect from small heart monitors they implanted last spring.

Hauling nearly $150,000 worth of computers, electrocardiographic recording devices, infrared cameras and ultrasound equipment (not to mention surgical equipment and 40 pounds of batteries) through the woods, the team set up a makeshift physiology lab on the snow only yards downhill from the snow-covered den in a knot of tree roots next to a small pond. For the next few hours they would use it to paint one of the most detailed pictures to date of a bear's inner workings.

It's already known that bears in hibernation don't eat, drink, urinate or defecate for five months. Yet they don't starve. By recycling their own waste, they avoid buildups of toxins. They don't exercise, yet they lose only a fraction of the muscle strength humans would if they were idle that long. Their hearts might slow to five beats per minute, yet they maintain heart strength and structure.

Unlike other animals such as squirrels, whose hibernation temperatures can drop to near freezing, bears' body temperatures drop only a few degrees. With predators (and researchers) combing the woods, they also remain alert and able to spring into action, contrary to the popular understanding of hibernation as a long snooze.

If humans someday could be made to perform the same tricks as bears, they might use them not to get through winter, but to recover from injury, surgery or long periods of bed rest. Iaizzo's lab has shown that substances that cause a bear to go into hibernation may have applications in humans to protect organs from damage from oxygen deprivation.

The National Aeronautics and Space Administration also has funded some research on bears in the belief that their retention of muscle strength could be adapted to help astronauts reduce atrophy during long periods in space.

"There are numerous things about bears that are miraculous, based on what we know about human physiology, and what we believe mammals can tolerate," Iaizzo said. "But the more work we do, the more questions that arise."

Little laboratory in the woods

Answers to some of those questions came in their north woods laboratory.

The team already knew that a hibernating bear might slow its heart and breathing to rates that would cause a human to faint, yet with a single breath could boost its heart's blood and oxygen-pumping capacity eightfold. They also knew that the mother bear they were testing was known for a high level of vigilance in hibernation.

"She's the angry female," said Brian Dirks, Camp Ripley animal survey coordinator. "She doesn't sleep very sound."

Tim Laske, an adjunct professor of surgery at the University of Minnesota and engineering director at Medtronic, learned that when he slipped a camera attached to a long stick into her den as she seemed to be slipping under the effects of a tranquilizer. In a flash she was lunging teeth-first at the lens.

More than an hour later, confident that the 251-pound mother bear was tranquilized, the team dragged her onto plastic yoga mats, where Laske would try to find the implanted heart monitor. It's a titanium device about the size of a computer flash drive, and Laske didn't have much hope. Bears have strong immune systems that have rejected devices in the past, and nine months in the brush can be tough on high-tech electronics.

Laske patted the bear's chest. "Here it is!" he shouted. Within minutes, Iaizzo had attached electrodes to the bear's chest and to a computer, and measurements of the bear's heart rate, stored since March 7, poured into a database.

It was, Iaizzo said, "data no one else really has from an animal that's been out in the wild for nine months."

Laske noted that the bear had experienced 60,126 episodes of bradycardia -- periods with extremely low heart rate, sometimes stopping altogether for as long as nine seconds. (One of the other bears reported pauses of more than 14 seconds.) Second assessment: She'd gone into hibernation in late November.

After the first data download, Iaizzo brought up some ultrasound images on a small screen of the interior of the bear's heart as it beat -- similar to those used to check development of fetuses. An electrocardiographic monitor measured the heart's electrical and mechanical activity.

After two hours of body measurements, blood tests and other exams by Dirks and DNR bear biologist Dave Garshelis, the mother and cub were shoved back into the den.

They won't remember a thing

The bears, Iaizzo said, wouldn't recall the encounter. But the researchers expect to be replaying it quite a bit, through the piles of data they downloaded.

Lynn Rogers, director of the North American Bear Center in Ely and a world-renowned bear researcher, said the implanted devices seem to corroborate research done several decades ago. "That's a good thing," he said. Rogers uses time and trust to approach bears and measure their heartbeats by hand; he said he would never use an implant. But he said he'll be interested in further results from the devices.

Laske and Iaizzo said researchers have their fingers crossed that some features of hibernation might someday be induced in humans. Conservation of the heart's energy, particularly, might help injured people's bodies focus on healing. Substances that induce hibernation might be used to preserve donor hearts for longer periods before they are transplanted, as well as to protect heart muscles from further damage after an attack.

"I think where we owe the bears a debt of gratitude is in learning things we previously didn't think were possible, and opening the minds of scientists to other possibilities of human therapies," Laske said.

At his home near the bear's den, Vilinski said he's looking forward to spring when the researchers return to check on the bear and her cub.

"Having [the bears] out here like this, I enjoy it," he said. "It's interesting. I just wish a guy could see her once in a while."

Bill McAuliffe • 612-673-7646

  • get related content delivered to your inbox

  • manage my email subscriptions

Click here to send us your hunting or fishing photos – and to see what others are showing off from around the region.

ADVERTISEMENT

Chicago 17 3rd Qtr 8:50
Detroit 24
Philadelphia 3:30 PM
Dallas
Seattle 7:30 PM
San Francisco
Cleveland 11/30/14 12:00 PM
Buffalo
Washington 11/30/14 12:00 PM
Indianapolis
Tennessee 11/30/14 12:00 PM
Houston
San Diego 11/30/14 12:00 PM
Baltimore
NY Giants 11/30/14 12:00 PM
Jacksonville
Cincinnati 11/30/14 12:00 PM
Tampa Bay
Oakland 11/30/14 12:00 PM
St. Louis
New Orleans 11/30/14 12:00 PM
Pittsburgh
Carolina 11/30/14 12:00 PM
Minnesota
Arizona 11/30/14 3:05 PM
Atlanta
New England 11/30/14 3:25 PM
Green Bay
Denver 11/30/14 7:30 PM
Kansas City
Miami 12/1/14 7:30 PM
NY Jets
Edmonton 7:00 PM
Nashville
ULM 54 FINAL
Robert Morris 71
Santa Clara 57 FINAL
Tennessee 64
Oklahoma 50 2nd Half 7:46
Butler 32
Austin Peay 33 1st Half 2:30
Brown 33
Princeton 20 1st Half 1:11
Texas-El Paso 23
Coastal Carolina 2 1st Half 17:41
Chattanooga 5
Kansas 0 1st Half 19:34
Rhode Island 0
Wisconsin 2:30 PM
Georgetown
FIU 2:30 PM
USC Upstate
Long Island 3:00 PM
Stony Brook
San Diego 3:30 PM
Xavier
Illinois 4:00 PM
Indiana State
Western Ky 5:00 PM
Saint Josephs
Cal State Fullerton 5:00 PM
Wright State
Michigan State 5:30 PM
Rider
UCLA 6:00 PM
North Carolina
Marquette 7:30 PM
Georgia Tech
Long Beach State 7:30 PM
Western Mich
Stephen F Austin 8:00 PM
Prairie View
UAB 8:30 PM
Florida
Rice 8:30 PM
Mercer
San Jose St 10:00 PM
Washington
Washington St 10:59 PM
UC Santa Barbara
Baylor 10:59 PM
Memphis
LSU 6:30 PM
Texas A&M
(6) TCU 6:30 PM
Texas
Northern Ill 11/28/14 10:00 AM
Western Mich
Nebraska 11/28/14 11:00 AM
Iowa
Western Ky 11/28/14 11:00 AM
(19) Marshall
UCF 11/28/14 11:00 AM
So Florida
Houston 11/28/14 11:00 AM
SMU
Akron 11/28/14 12:00 PM
Kent State
Ball State 11/28/14 12:00 PM
Bowling Green
Buffalo 11/28/14 12:00 PM
Massachusetts
Toledo 11/28/14 12:00 PM
Eastern Mich
Arkansas 11/28/14 1:30 PM
(17) Missouri
Navy 11/28/14 2:00 PM
South Alabama
(13) Arizona State 11/28/14 2:30 PM
(12) Arizona
Stanford 11/28/14 2:30 PM
(9) UCLA
(21) Colorado State 11/28/14 2:30 PM
Air Force
Virginia 11/28/14 7:00 PM
Virginia Tech
East Carolina 11/28/14 7:30 PM
Tulsa
North Texas 11/29/14 11:00 AM
TX-San Antonio
Old Dominion 11/29/14 11:00 AM
Fla Atlantic
(16) Georgia Tech 11/29/14 11:00 AM
(8) Georgia
Kentucky 11/29/14 11:00 AM
(24) Louisville
So Carolina 11/29/14 11:00 AM
(23) Clemson
West Virginia 11/29/14 11:00 AM
Iowa State
Rice 11/29/14 11:00 AM
Louisiana Tech
Michigan 11/29/14 11:00 AM
(7) Ohio State
Purdue 11/29/14 11:00 AM
Indiana
Illinois 11/29/14 11:00 AM
Northwestern
Cincinnati 11/29/14 11:00 AM
Temple
NC State 11/29/14 11:30 AM
North Carolina
Syracuse 11/29/14 11:30 AM
Boston College
Louisiana 11/29/14 11:30 AM
Troy
Utah 11/29/14 12:00 PM
Colorado
Texas State 11/29/14 1:00 PM
Georgia State
Idaho 11/29/14 1:00 PM
Appalachian St
Wyoming 11/29/14 2:00 PM
New Mexico
New Mexico St 11/29/14 2:00 PM
Arkansas State
UAB 11/29/14 2:30 PM
Southern Miss
(4) Miss State 11/29/14 2:30 PM
(18) Ole Miss
Notre Dame 11/29/14 2:30 PM
USC
(10) Michigan State 11/29/14 2:30 PM
Penn State
(22) Minnesota 11/29/14 2:30 PM
(14) Wisconsin
(5) Baylor 11/29/14 2:30 PM
Texas Tech
Florida 11/29/14 2:30 PM
(1) Florida State
Rutgers 11/29/14 2:30 PM
Maryland
San Jose St 11/29/14 2:30 PM
San Diego St
Tennessee 11/29/14 3:00 PM
Vanderbilt
Kansas 11/29/14 3:00 PM
(11) Kansas State
Connecticut 11/29/14 3:00 PM
Memphis
BYU 11/29/14 3:30 PM
California
ULM 11/29/14 5:00 PM
Ga Southern
Middle Tennessee 11/29/14 6:00 PM
Texas-El Paso
Hawaii 11/29/14 6:00 PM
Fresno State
Wake Forest 11/29/14 6:00 PM
Duke
Pittsburgh 11/29/14 6:00 PM
Miami-Florida
(15) Auburn 11/29/14 6:45 PM
(2) Alabama
(3) Oregon 11/29/14 7:00 PM
Oregon State
Utah State 11/29/14 9:15 PM
(25) Boise State
Washington 11/29/14 9:30 PM
Washington St
Nevada 11/29/14 9:30 PM
UNLV
UCF 12/4/14 6:30 PM
East Carolina
Hamilton 11/30/14 5:00 PM
Calgary
Hartford 39 2nd Half 3:58
Furman 47
Clemson 54 2nd Half 11:06
Ohio State 52
Idaho State 20 1st Half 4:48
San Diego State 23
East Carolina 18 1st Half 3:55
(22) Syracuse 43
Santa Clara 2:30 PM
Texas-El Paso
Florida State 2:30 PM
Washington
Wichita State 2:30 PM
Fla Gulf Coast
Wisconsin 3:15 PM
(1) South Carolina
BYU 5:00 PM
BYU-Hawaii
Kansas State 5:00 PM
LSU
Charlotte 5:00 PM
Montana
Illinois 5:00 PM
(9) Kentucky
Central Michigan 7:00 PM
Richmond
Oklahoma 7:15 PM
South Florida
Princeton 7:30 PM
Wake Forest
(19) Oregon State 8:00 PM
Butler
Connect with twitterConnect with facebookConnect with Google+Connect with PinterestConnect with PinterestConnect with RssfeedConnect with email newsletters

ADVERTISEMENT

ADVERTISEMENT

ADVERTISEMENT

ADVERTISEMENT

question of the day

Poll: Should the lake where the albino muskie was caught remain a mystery?

Weekly Question

ADVERTISEMENT

 
Close