Undergraduate Research

By John Gagnon

Regenerating the Nervous System

The nervous system is one of the most complex in the human body, and Jared Cregg, a junior in biomedical engineering, wants to develop ways to help it regenerate after injury.

It's an ambitious goal, he says, because "the central nervous system is the part of the body that gives us cognizance."

Neurons, he explains, "innervate muscles, organs, and glands. They give us feeling. They regulate the heart rate and control muscle activity. A transected nerve in the peripheral system (arms and legs) can prevent normal functioning of a limb, or, if the spinal cord is cut, can prevent functioning in the majority of the body."

Once cut, neurons within the spinal cord try to regenerate, but do so haphazardly, and they can't make their way through scar tissue.

Ultimately, severed neurons degenerate and atrophy, which leads to paralysis.

There are no treatments for paralysis beyond extensive physical therapy. The abiding goal of researchers: reestablish lost functions like sensation, locomotion, and even breathing.

Cregg is fascinated with those prospects.

Under the direction of Assistant Professor Ryan Gilbert, he uses polymeric biomaterials—"small, smart stuff"—that he uses to construct "conduits" to manipulate the direction of neuronal growth.

He sees such inquiry as a lifelong ambition.

"Focusing on the nervous system is something I would love to do," he says. He aspires to "advance the field"—understand disease or injury and how it could be treated.

As an undergraduate researcher, Cregg has the perspective of a seasoned scientist: "You have to trust the many scientists who have worked so hard to discover these things before you," he says. "You have to have faith in science in order to be a successful scientist. We're only beginning to understand how complex computers,

like ourselves, work." He appreciates the opportunity to work with faculty like Gilbert. "They help me figure out if ideas are valuable or flawed. You can have tons of ideas, but the laboratory

work is most important. Without spending time in the lab, ideas are just ideas."

There is a worldwide effort to understand the nervous system and develop artificial materials that can trigger efficient nerve regeneration.

Cregg sees himself as a small part of this big job. "I'd just like to contribute," he says.

A Small World in a Universe

Michigan Tech researchers, addressing osteoarthritis, have discovered something unforeseen and intriguing, but only time will tell the impact it may have on society.

The research involved is part of Associate Professor Tammy Haut-Donahue's quest to prevent osteoarthritis, a common and painful disability that affects more than twenty million Americans.

The condition results from the breakdown of joint cartilage, which covers the ends of bones. With less cushion, more cartilage is worn away, and a painful rubbing of bone on bone occurs.

Haut-Donahue's inquiry centers on the knee, in particular, the meniscus, which includes two crescent-shaped buffers of fibrocartilage that disperse friction and distribute the load where the femur and tibia meet in the knee joint.

It's a broad investigation that involves collaboration with scientists at Michigan State University. At Tech, Haut-Donahue leads a research team of five doctoral students and three undergraduates.

One of the latter is Nicole Lepinski, a Minnesota native who is looking into the degradation of the meniscal cartilage as a result of traumatic injury.

Lepinski, a senior, has looked at how the meniscus responds to a damaged anterior cruciate ligament (ACL), a tough strap of tissue that helps hold the knee in place. Her research looks at the number of cells in the meniscal tissue and the subsequent changes in cell density as the tissue degrades.

In an attempt to understand sports injuries, other researchers have surgically severed the ACL and assessed the impact of the cut on the knee joint meniscus. They found little or no changes. This is not natural, however, as normally there is an impact that occurs to traumatically tear the ACL, such as during a jump landing in basketball.

Lepinski's work is novel: instead of cutting the ACL, she works with impacted knee joint models with torn ACLs, as would occur in many sports-related injuries.

Lepinski's finding: the meniscus morphology is altered and shows signs of degradation when the ACL is torn traumatically.

"The number of cells seems to stay the same, but the density has increased," she says.

"Her findings aren't what we expected," Haut-Donahue says. "In fact, we were expecting to see a decrease in the number of cells."

The significance? "There are, in fact, changes that occur in the meniscus following traumatic ACL injury, and, therefore, surgeons might need to treat the meniscus as well as the torn ACL to prevent osteoarthritis," Haut-Donahue says.

As well, once scientists understand the complicated processes that lead to degeneration of the knee joint, they could develop treatments to protect the meniscal cartilage following trauma and prevent the underlying articular cartilage in the knee joint from deteriorating in the first place.

Lepinski's work included authorship of a scholarly paper. She describes her project as "a great academic opportunity that could one day have even greater medical applications."

"I've always been interested in life processes," she adds. "Our bodies are their own universe."

Michigan Technological University is a public research university, home to more than 7,000 students from 54 countries. Founded in 1885, the University offers more than 120 undergraduate and graduate degree programs in science and technology, engineering, forestry, business and economics, health professions, humanities, mathematics, and social sciences. Our campus in Michigan’s Upper Peninsula overlooks the Keweenaw Waterway and is just a few miles from Lake Superior.