The muscle demystifier

Adam Kuchnia stands in front of a projected 3D image of human torso muscles created from dozens of cross-sectional CT scans. Photo by Michael P. King

Adam Kuchnia, ’06, is using diagnostic imaging to enhance the understanding of human muscles and explore better treatments for muscle-wasting diseases

Courtesy of Nicole Sweeney Etter, UW-Madison Life Sciences

As a wrestler at UW–La Crosse, Adam Kuchnia lost a lot of pounds so he could compete in a particular weight class. And that didn’t always lead to the best nutritional choices.

“I started to notice how good and bad nutrition felt when I was competing and the outcomes of poor nutrition,” says Kuchnia, who is now an assistant professor in the Department of Nutritional Sciences. “When I was eating poorly, whether it was too few calories or a lot of fast food, I saw my energy levels decline. My performance declined drastically — I didn’t have any energy to compete at the level that I was capable of competing at because I wasn’t following the proper nutrition prescription. So that really snowballed into wondering how nutrition, specifically protein, changes the body and affects the way we move, perform and think.”

“I feel like I have a responsibility to the state of Wisconsin to give back.”

It was a wake-up call that would inspire Kuchnia to shift his career focus from exercise science to nutritional sciences. And even after he hung up his collegiate wrestling shoes, he continued to stay active and look for ways to enhance his own fitness. “I was always into exercise and always had this interest in trying to maintain and build muscle,” he explains. “My interest in proteins, amino acids, athletics and performance really pushed me into clinical nutrition. I wanted to get a deeper understanding of how nutrition impacts your body at a cellular level.”

Now Kuchnia’s research lab is focused on developing imaging techniques to more accurately evaluate muscle as it responds to aging and disease and how to best treat muscle wasting.

What is it about muscle that fascinates you?

It’s important for everything. You need muscle to build an immune response when you’re sick. It’s important for movement, for function. To be healthy, you have to have an adequate amount of muscle — and healthy muscle to boot. It’s just paramount. And yet, knowing how important muscle is to health and wellness and mobility, we still don’t have good objective markers to characterize it.

Why is is important to characterize muscle in aging in disease?

We’re looking at how we can characterize muscle quantity and, more importantly, muscle quality. Currently, clinicians and nutrition professionals are subjectively palpating muscle, and it’s not as accurate as I think this sort of assessment needs to be.

We also look at muscle to diagnose malnutrition, and we’re still using some of the same techniques to assess nutrition that people used to observe illness over 1,800 years ago — looking at the fat pads under the eyes, ribs, clavicles, shoulders. We’re trying to say something about nutritional status just by looking and touching; and nutrition professionals, clinicians and physicians are forced to use this visual inspection because there’s nothing better. Someone might seem nourished just by looking at them because you may not see any obvious muscle degradation, but if you get advanced imaging data, you might actually see signs of muscle loss.

There’s so much imaging and technology that’s available now that I think we can get a better, more accurate picture of what’s going on inside the muscle. Essentially, we are trying to come up with an imaging-based biomarker of muscle quality that can be used to appraise and guide therapeutic intervention. Utilizing more invasive procedures, such as MRI, CT, DXA (which measures muscle mass and bone density), and biopsy, we hope to develop noninvasive and inexpensive methods that can objectively characterize changes in muscle. All of this can be used to improve functional status, independence, quality of life and mortality.

Why is it important to look at muscle quality as well as quantity?

Muscle quality is still a vague term; we’re still trying to figure out what that means. Back in the late 1990s, early 2000s, researchers were looking at older people and saw their muscle quantity had gone down a little, but their physical function had dropped drastically. What is accounting for this discrepancy? Today there is good evidence that a loss of muscle quality precedes loss of muscle quantity.

Are there particular populations that would especially benefit from this type of muscle assessment?

It’s very important for everybody but especially for people who are hospitalized. When people go into the hospital, they’re immobile. They have an immediate inflammatory response that leads to muscle loss. Then, when you add in disease that leads to muscle wasting, such as critical illness or cancer, the effects are catastrophic. If we can identify these changes in muscle earlier, we can intervene earlier.

So once we can better characterize muscle decline, what can we do about it?

We can intervene in many different ways, but I’m focused on nutritional intervention, specifically protein and amino acids. When people are going through cancer or are in the ICU and are having this huge inflammatory response, we don’t really know the right levels or types of proteins and amino acids to give them. If we give them too much, we could be harming them. But if we give them the right amount and type, we could help increase protein synthesis, reduce protein breakdown and reduce muscle wasting. We’re trying to improve patient outcomes so they get out of the hospital sooner, and so, when they leave, they have a quality of life that’s meaningful for them.

When does age-related muscle loss start to happen? Is there anything we can do to lessen its effects?

Sarcopenia, which is what we call age-related muscle loss, starts to happen in mid-adulthood. We lose roughly 3 to 8 percent of our muscle mass per decade after the age of 30, and that increases substantially as you hit 60. But that’s just muscle quantity. I’m trying to look at muscle quality. How much is actually active, functional muscle?

Even the healthiest people we know lose muscle as they age, but you can definitely slow down the process with proper nutrition, regular exercise and an overall healthy lifestyle.

What’s next for your lab?

I’ve been here less than a year, so the next thing is growing my lab, really carving out the physical space and hiring the right students and lab assistants. Then it’s trying to get to the bottom of these muscle-wasting syndromes. There are so many questions there.

You’re a product of the UW System. What’s it like to be back at a UW campus as a faculty member?

It’s pretty special. I grew up in Twin Lakes, did my undergrad degree at UW–La Crosse and then went to UW–Stout for my master’s degree. I feel like I have a responsibility to the state of Wisconsin to give back. We talk a lot about the Wisconsin Idea here — giving back not only to the university but to the community at large. I really like that my research can help benefit the place where I grew up.

After I finished my doctorate at the University of Minnesota, I was willing to go anywhere from coast to coast, but I was very lucky when this position opened up. It’s a phenomenal department. I couldn’t be happier here.