The Thinkers
This monthly series will highlight people from Western Pennsylvania who are on the forefront of new ideas in their fields.
Older Americans are healthier than ever before.
But there are also a lot more of them, and as the baby boomers get ready to surge into retirement, the sheer number of people with chronic disabilities will undoubtedly increase, including more than 1 million people who will have to rely on wheelchairs.
Unless current policies change, that could also mean more and more people will be afflicted with nagging shoulder injuries, carpal tunnel syndrome and other problems that come from using lower-grade, badly adjusted wheelchairs, says University of Pittsburgh researcher Fabrisia Ambrosio.
Dr. Ambrosio, who has training in both physical therapy and basic muscle research, learned a lot about wheelchair design when she worked at the Human Engineering Research Laboratories at the VA Pittsburgh Healthcare System.
One trend she noticed was that the most severely disabled patients -- people paralyzed by spinal cord injuries -- often had the best wheelchairs, while those with more chronic diseases -- such as multiple sclerosis -- often ended up with the lower-quality models.
Because spinal cord injuries are sudden and catastrophic, those patients often are quickly referred to a battery of specialists, including experts in choosing the best kind of wheelchair.
People who gradually have lost mobility and have gone into wheelchairs later in life, on the other hand, are often "coming in with these really low-grade wheelchairs that they have gotten from the church fair or were passed down from Aunt Mary," she said.
The result? Those people were much more likely to develop tendonitis and other shoulder problems or wrist injuries from pushing heavier chairs that were poorly aligned.
She and her colleagues found that the best way to avoid those injuries was to use an ultralight wheelchair with wheel axles that could adjust both forward and back, and up and down.
The ideal position for most manual chair users, Dr. Ambrosio said, is for their elbows to be at a 120-degree angle when their hands are placed on top of the wheels. That puts the least stress on the shoulders, which were never meant to be weight-bearing joints, and also allows the most efficient forward push.
Unfortunately, she said, health insurance reimbursement policies today often favor cheaper chairs, in the $500-$600 range, rather than ultralight, adjustable chairs that can cost roughly $2,000.
Over the long haul, though, the more expensive chairs would actually be cheaper because they would sharply cut down on the cost of treatment for injuries, and would last longer, she said.
Benefit in motorized chairs
For some people, she said, motorized wheelchairs or scooters make more sense, even if they resist them.
That is often an issue in multiple sclerosis, which causes increasing muscle control problems as the myelin sheath that lines the nerves deteriorates.
MS is "generally a slowly progressing disease, so many people feel transitioning to a wheelchair is almost a sign of giving up," Dr. Ambrosio said. On top of that, she said, people with MS often want to use a manual wheelchair in the mistaken belief that it will help preserve their strength.
Her study showed, however, that those with MS who used motorized chairs were able to participate in more daily activities, such as shopping or going to the movies, than manual chair users, without any greater loss of muscle strength.
Motorized chairs also often make sense for diseases such as Duchenne muscular dystrophy, a lethal inherited disorder, mostly affecting boys, in which the body cannot make a structural muscle protein called dystrophin.
MD is one of the diseases Dr. Ambrosio is working on as an investigator at Pitt's Stem Cell Research Center, headed by Dr. Johnny Huard.
Dr. Huard has developed a line of muscle stem cells that he hopes can be used one day to treat everything from MD to bladder problems to rheumatoid arthritis to heart disease.
Stem cells are early versions of cells that have the ability to differentiate into more specialized cells. The Huard lab's stem cells have been able to metamorphose into bone, cartilage and different kinds of muscle.
In the MD research, Dr. Ambrosio and others are injecting the stem cells into mice that have a form of muscular dystrophy. In the process, they're discovering the disease is even more complicated than previously believed.
Some of the early work showed that the mice that received the stem cells were making dystrophin, which provides a kind of scaffolding for muscle cells, but their muscles weren't necessarily any stronger as a result.
Dr. Ambrosio's group theorized that the mice might need to exercise to provide the signals needed for the stem cells to bolster muscle strength, and so far, experiments seem to be proving that point.
Sports injuries led to role
Born in Brazil, Dr. Ambrosio spent her later teens in north central Pennsylvania, where her father is a physics professor at Mansfield University.
She became interested in physical therapy partly because of her own experience with ankle sprains while running on a cross-country team.
After earning a bachelor's in biology at Mansfield in 1996, she won a scholarship to get a master's of science degree in skeletal muscle physiology at Laval University in Quebec.
Dr. Ambrosio, who gave birth to her second child last week, went on to get her Ph.D. in rehabilitation science at Pitt two years ago.
Much of her work has focused on a type of cell known as a satellite cell.
Satellite cells lie just beneath the sheath that surrounds muscle fibers, and they seem to serve as rejuvenation and repair factories for the muscle tissue.
In body builders, the intense weight training they undergo increases the pool of satellite cells, she said, but in MD, the constant breakdown and repair of the muscle fibers depletes the overworked satellite cells.
"In people with MD," she said "that satellite cell pool just becomes exhausted. It's almost like a premature aging."
If her laboratory's stem cells can be coaxed into creating new stem cells, more satellite cells and a substance known as growth factor, it creates the exciting possibility that one day, scientists might be able to halt the muscle wasting in MD.
Although they haven't done any human trials yet, the early results are encouraging, she said.
"The basis of a lot of the research we're doing now is trying to couple the stem cell transplantation with exercise [in the mice], and in fact we've seen we can increase the participation of these stem cells in muscle regeneration."
Correction/Clarification: (Published June 27, 2007) The best arm position for a manual wheelchair user is for the elbows to form a 120-degree angle when the person's hands are on top of the wheels. An incorrect angle was cited in this story as originally published June 25, 2007 describing the research of the University of Pittsburgh's Fabrisia Ambrosio.
Fabrisia AmbrosioPosition: Professor, physical medicine and rehabilitation, University of Pittsburgh; investigator, Stem Cell Research Center.
Age: 31
Residence: Forest Hills
Education: Bachelor's in biology, Mansfield University, Mansfield, Pa., 1996; master's in science, Laval University, Quebec, 1998; master's in physical therapy, Medical College of Pennsylvania and Hahnemann University, Philadelphia, 1999; Ph.D., rehabilitation science and technology, University of Pittsburgh, 2005.
Previous positions: Research assistant, Human Engineering Research Laboratories, VA Pittsburgh Healthcare System, 2001-03.
Academic honors: Best paper, multiple sclerosis research, Consortium of Multiple Sclerosis Centers, 2002.
Publications: Six papers in refereed journals and one book chapter.
Experiments using muscle stem cells to treat urinary incontinence
The possibility of using electrical stimulation on coma patients
The benefits of "standing wheelchairs"
First Published: June 25, 2007, 3:15 a.m.
