TMC PULSE

t m c » p u l s e | n o v e m b e r 2 0 1 9 8 He advises protecting muscle from a young adult age, because its loss tends to sneak up on people. "If you want to protect your muscle health, your function, your glucose and metabolism from the ravages of age, inactivity or disease, you've really only got three options: exercise, drugs and nutrition," he said. "In my mind, it's nutrition that you have to optimize for any of these other areas to work optimally. We want to get patients out of bed, but there's a risk and a cost associated with that. Same with drugs—they can work, but not for everyone. But we absolutely have to feed every sin- gle person, so why not tweak that? You've got to eat, but you've got to be pragmatic and efficient about it." One option for building and repairing muscles is the amino acid leucine, one of the most abundant amino acids in protein-filled foods. Some of Paddon-Jones' bed rest studies have examined leucine's effect on the body. "Leucine is one of the essential amino acids, one of the building blocks," he said. "It's special because it serves as a trigger or a switch that turns on the molecular pathways that build and repair muscle. The optimal thing is to turn it on every now and again—little bouts where you increase the leucine." Results from bed rest studies have shown that leucine can safe- guard against some muscle loss. An average middle-aged man lost about two pounds of muscle from his legs after just one week of bed rest, Paddon-Jones said. But the group that received leucine—four grams delivered three times a day in powder form, for a total of 12 grams daily—fared better. "The group we gave leucine to, over the first seven days, lost half as much muscle," Paddon-Jones said. "It has a short-term protective effect. And 12 grams a day? That's a really small amount." Instead of buying leucine as a supplement in a health and wellness store, integrate it into your diet, he added. "If you ate five ounces of beef, you'd get about three grams of leu- cine," Paddon-Jones said. "In a glass of milk you'll get a good amount, Watowich and his team showed that in older mice treated with the drug, muscle fiber size and muscle strength nearly doubled. In addi- tion, no adverse effects of the drug were found. Watowich has been working on RT-001 for three years and it will be at least another four, he estimates, before it is released to the public. More testing is yet to come. "The idea is to see how much compound you can give clinical models over a month-long period," he said. "You're looking to make sure you're not causing problems and you want to establish an upper dose." The drug does not mean that adults get a pass on eating well and exercising, he asserted. The pill will be more effective for people who take care of their bodies. "Our drug actually stimulates the stem cells and allows them to repair injured muscles," Watowich said. "It'll work better the more you work the muscles, but it'll even help maintain daily activity." Activity, drugs, nutrition Physical activity and diet play a vital role in protecting muscle health. In the department of nutrition and metabolism at UTMB, Doug Paddon-Jones, Ph.D., studies how to retain muscle strength and how to consume proteins to help with this process. "In the best-case scenario, once you hit 35 or 40, depending on how well you've looked after yourself, you lose a little bit of muscle each year," Paddon-Jones explained. "It's insidious and slow. From age 40 to 60, you can make up for it with sub- tle lifestyle changes. Even though you are losing a little bit, your body fat tends to slide up around the same time, so bathroom scales are useless. Your body weight may not change, but body composition is starting to go in a pudgy direction." Paddon-Jones and his team have done several bed rest studies, mimicking the inpatient experience in hospitals, to examine the loss of muscle from inactivity and sarco- penia, which is age-related muscle degeneration. "Some folks on bed rest, the muscle just falls off them," Paddon- Jones said. "Other people are kind of resilient. From a practical perspective, intervention should be geared to a worse-case scenario, because even if you're resilient now, you may not be your entire life. " Above: Doug Paddon-Jones, Ph.D., the Sheridan Lorenz Distinguished Professor in Aging and Health at UTMB, researches muscle mass and function in healthy and clinical populations. Far right: Watowich holds a sample in his lab.

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