Muscles: more important than you realize

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[img_inline align=”right” src=”http://padnws01.mcmaster.ca/images/Phillips_Stuart-01.jpg” caption=”Stuart Phillips. Photo credit: Graham Jansz”]Each year an ever-expanding collection of birthday candles serves as a reminder that we are all getting older. Aging brings with it many joys: life experiences, pearls of wisdom, new hobbies, perhaps grandchildren. Inevitably, it also entails increased physical frailty marked by realities such as dwindling muscles. Decreased muscle mass leads to weakness. Muscle weakness can result in dangerous falls which cripple thousands leading to an estimated $2.4 billion in direct health care costs and forcing many seniors to move into nursing homes.

According to McMaster University researcher Stuart Phillips, “It may seem simple to you or I, but simply rising from a chair can be a very tough activity for somebody who doesn't have very strong muscles.” Our muscles are crucial aspects of our bodies, and it is very easy to take them for granted.

Phillips, an associate professor in the Department of Kinesiology, knows that “If we can design resistance programs or give people who are older good nutrition to help them hang on to what little muscle they have, then we can prevent their entry into a nursing home by one, two, perhaps three years – and that represents a very significant event in the heath-related quality of life for that individual since it allows them to be autonomous and continue their life in their home. Additionally, it also represents an enormous cost saving to the healthcare system.”

Phillips' research program focuses on both ends of a continuum of people gaining and losing muscle mass. He notes, “We have young people who are gaining muscle mass and then at the other end of the scale people who are losing skeletal muscle mass. We've done some research on both ends of the scale to try and understand what it is about resistance exercise and nutrition that allows new muscle to be made. What pushes the buttons to make the [muscle] get bigger, shrink, or stay the same?”

The Natural Sciences and Engineering Research Council (NSERC) of Canada has supported Phillips' research, and recently he and his colleagues Mark Tarnopolsky also from McMaster and Michael Rennie from the University of Nottingham were given a prestigious Collaborative Health Research Project (CHRP) award. This award is designed to support collaborative research projects that lead to health benefits for Canadians.

To help promote skeletal muscle growth and maintenance, Phillips studies muscles at the cellular level. With the help of these grants and awards, Phillips has set up a cutting-edge lab to study muscle biochemistry. Specifically, he uses biochemical markers known as 'stable isotope labeled amino acids.'

Muscles are made up of collections of specialized proteins. These proteins are in turn made up of building blocks called amino acids. Therefore, whenever new muscle tissue is made, new amino acids are required as the starting materials. As part of his experiments Phillips supplies his test subject's bodies with the necessary amino acids to build muscle; however, before he does so he replaces some of the normal atoms in the amino acid with a slightly modified atom called an 'isotope.' These isotopes can be detected using highly sensitive equipment.

Often, Phillips will ask his subjects to follow a specific exercise and nutrition program. After the program, he takes samples of muscle from his volunteers and tests to see if any of the special isotope labeled amino acids have being integrated. If he does find isotopes in the muscle, he knows that the muscle has been recently built-up and that the specific program he was testing promotes muscular growth.

This is a remarkable and extremely innovative technique. Typically changes in muscle can only be observed over relatively long periods of time – you don't see your muscles grow after a few days of push-ups. Phillips' method, however, provides a very fast and accurate way to see if muscle is growing – he can measure growth within hours. According to Phillips, “There are not many labs in the world that can do that – probably about five or six. We're it in Canada.”

Phillips' studies of muscles are not only applicable to aging, there are several other situations when muscle mass can be lost. For example, limbs that have been in a cast typically emerge with much less muscle than when they entered. Phillips' latest research project aims to help people who are forced to be immobile to maintain as much muscle mass as possible. This will help to facilitate a fast and more complete recovery when mobility is regained.

Phillips' research is also helping those who suffer from seemingly permanent immobility – victims of spinal cord injury. Phillips says, “We've shown that we can restore some skeletal muscle mass to their legs that allows them to do certain things like stand at a counter or even learn to almost 'walk again' – to take five or 10 unassisted steps. You can imagine how fantastic that must be for somebody who has been wheelchair confined most of the time.”

Although mobility and movement are the most obvious functions of muscles, they are certainly not the only ones. Understanding the other jobs our muscles perform reveals even further applications of Phillips' research. Phillips observes, “What we're beginning to appreciate now is that the skeletal muscle is like the furnace of the body. Furnaces burn fuel; the fuels we burn in our bodies are fats and blood-sugar.” Even when we are not moving, our muscles still burn this fuel to keep our bodies running – this basic energy consumption is what people typically refer to as their 'metabolism.'

Having a 'high metabolism' means that a body burns lots of energy, even when it is resting. This energy consumption is directly related to how much muscle a person has – and it is important for much more than burning off a donut's worth of calories. Phillips says, “When you burn glucose quicker it means that your risk for diabetes is lower. When you burn fats, your risk for heart disease is lower. That all comes down to how big the furnace is and how well it functions. If you want to maintain a relatively low risk for diabetes and heart disease, make sure you have a lot of well-functioning muscle mass. In other words, exercise.”

Impacting real people with real needs, injuries, and diseases is the driving force of Phillips' research. He states, “[my research] is aimed at determining why things happen at the muscle and cellular levels; but for these people with muscle mass problems it just represents an absolutely massive shift in how they view life and everything else. That is enormously gratifying to me. It's not that I don't enjoy watching young people get stronger and watching and understanding how their muscles grow, but the clinical aspect of that knowledge is what really turns my crank. As my research leads to a better understanding of how muscle grows or shrinks we will help to improve the quality of life for many Canadians.”

(The Natural Sciences and Engineering Research Council SPARK (Students Promoting Awareness of Research Knowledge) program was launched in 1999 at 10 universities across Canada. Through SPARK, students with an aptitude for communications are recruited, trained and paid to write stories based on the NSERC supported research at participating universities.)