muscle
Snapshots of Life: Building Muscle in a Dish
Credit: Kevin Murach, Charlotte Peterson, and John McCarthy, University of Kentucky, Lexington
As many of us know from hard experience, tearing a muscle while exercising can be a real pain. The good news is that injured muscle will usually heal quickly for many of us with the help of satellite cells. Never heard of them? They are the adult stem cells in our skeletal muscles long recognized for their capacity to make new muscle fibers called myotubes.
This striking image shows what happens when satellite cells from mice are cultured in a lab dish. With small adjustments to the lab dish’s growth media, those cells fuse to form myotubes. Here, you see the striated myotubes (red) with multiple cell nuclei (blue) characteristic of mature muscle fibers. The researchers also used a virus to genetically engineer some of the muscle to express a fluorescent protein (green).
Tags: aging, exercise, FASEB Bioart 2017, fluorescence microscopy, muscle, muscle fibers, myotubes, satellite cells, senior health, skeletal muscle
Sharing a Story of Hope
Whether by snail mail, email, or social media, it’s the time of year for catching up with family and friends. As NIH Director, I’m also fortunate to hear from some of the amazing people who’ve been helped by NIH research. Among the greetings to arrive in my inbox this holiday season is this incredible video from a 15-year-old named Aaron, who is fortunate enough to count two states—Alabama and Colorado—as his home.
As a young boy, Aaron was naturally athletic, speeding around the baseball diamond and competing on the ski slopes in freestyle mogul. But around the age of 10, Aaron noticed something strange. He couldn’t move as fast as usual. Aaron pushed himself to get back up to speed, but his muscles grew progressively weaker.
Posted In: Health, Science, Video
Tags: anti-HMGCR myopathy, antibodies, autoimmunity, childhood diseases, clinical research, clinical trials, immunology, intravenous immunoglobulins, IVIG, muscle, muscle diseases, muscular dystrophy, myopathy, statins
Snapshots of Life: Muscling in on Development
Credit: Mary P. Colasanto, University of Utah, Salt Lake City
Twice a week, I do an hour of weight training to maintain muscle strength and tone. Millions of Americans do the same, and there’s always a lot of attention paid to those upper arm muscles—the biceps and triceps. Less appreciated is another arm muscle that pumps right along during workouts: the brachialis. This muscle—located under the biceps—helps your elbow flex when you are doing all kinds of things, whether curling a 50-pound barbell or just grabbing a bag of groceries or your luggage out of the car.
Now, scientific studies of the triceps and brachialis are providing important clues about how the body’s 40 different types of limb muscles assume their distinct identities during development [1]. In these images from the NIH-supported lab of Gabrielle Kardon at the University of Utah, Salt Lake City, you see the developing forelimb of a healthy mouse strain (top) compared to that of a mutant mouse strain with a stiff, abnormal gait (bottom).
Tags: brachialis, connective tissue, development, FluoRender, forelimb muscles, genetics, genomics, lateral triceps, limb muscles, limbs, mouse, mouse genetics, muscle, musculoskeletal disorder, rare disease, Tbx3, transcription factor, triceps, ulnar-mammary syndrome, UMS, University of Utah’s 2016 Research as Art
Muscle Enzyme Explains Weight Gain in Middle Age
Thinkstock/tetmc
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!
Tags: aging, aging process, biochemistry, diabetes, diet, DNA repair, DNA-PK, DNA-PK inhibitor, fat, healthy weight, lymphocytes, metabolism, middle age, mitochondria, muscle, obesity, overweight, physical fitness, SCID, severe combined immunodeficiency, skeletal muscle, weight gain, weight loss, weight loss medication
Snapshots of Life: Picturing the Developing Windpipe
Randee Young and Xin Sun, University of Wisconsin–Madison
The image above shows a small section of the trachea, or windpipe, of a developing mouse. Although it’s only about the diameter of a pinhead at this stage of development, the mouse trachea has a lot in common structurally with the much wider and longer human trachea. Both develop from a precisely engineered balance between the flexibility of smooth muscle and the supportive strength and durability of cartilage.
Here you can catch a glimpse of this balance. C-rings of cartilage (red) wrap around the back of the trachea, providing the support needed to keep its tube open during breathing. Attached to the ends of the rings are dark shadowy bands of smooth muscles, which are connected to a web of nerves (green). The tension supplied by the muscle cells is essential for proper development of those neatly organized cartilage rings.
Tags: airways, cartilage, cartilage rings, congenital tracheomalacia, development, FASEB Bioart 2016, mineralized tissue, muscle, pulmonary disease, rare disease, respiratory system, smooth muscle, trachea, trachea development, upper airway, windpipe
