Muscle Enzyme Explains Weight Gain in Middle Age

Woman weighing herself

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The struggle to maintain a healthy weight is a lifelong challenge for many of us. In fact, the average American packs on an extra 30 pounds from early adulthood to age 50. What’s responsible for this tendency toward middle-age spread? For most of us, too many calories and too little exercise definitely play a role. But now comes word that another reason may lie in a strong—and previously unknown—biochemical mechanism related to the normal aging process.

An NIH-led team recently discovered that the normal process of aging causes levels of an enzyme called DNA-PK to rise in animals as they approach middle age. While the enzyme is known for its role in DNA repair, their studies show it also slows down metabolism, making it more difficult to burn fat. To see if reducing DNA-PK levels might rev up the metabolism, the researchers turned to middle-aged mice. They found that a drug-like compound that blocked DNA-PK activity cut weight gain in the mice by a whopping 40 percent!

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Exercise Releases Brain-Healthy Protein

ExerciseWe all know that exercise is important for a strong and healthy body. Less appreciated is that exercise seems also to be important for a strong and healthy mind, boosting memory and learning, while possibly delaying age-related cognitive decline [1]. How is this so? Researchers have assembled a growing body of evidence that suggests skeletal muscle cells secrete proteins and other factors into the blood during exercise that have a regenerative effect on the brain.

Now, an NIH-supported study has identified a new biochemical candidate to help explore the muscle-brain connection: a protein secreted by skeletal muscle cells called cathepsin B. The study found that levels of this protein rise in the blood of people who exercise regularly, in this case running on a treadmill. In mice, brain cells treated with the protein also exhibited molecular changes associated with the production of new neurons. Interestingly, the researchers found that the memory boost normally provided by exercise is diminished in mice unable to produce cathepsin B.

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Sound Advice: High School Music Training Sharpens Language Skills

Band InstrumentsWhen children enter the first grade, their brains are primed for learning experiences, significantly more so, in fact, than adult brains. For instance, scientists have documented that musical training during grade school produces a signature set of benefits for the brain and for behavior—benefits that can last a lifetime, whether or not people continue to play music.

Now, researchers at Northwestern University, Evanston, IL, have some good news for teenagers who missed out on learning to play musical instruments as young kids. Even when musical training isn’t started until high school, it produces meaningful changes in how the brain processes sound. And those changes have positive benefits not only for a teen’s musical abilities, but also for skills related to reading and writing.

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