Muscle Loss With Aging (Sarcopenia) Treatment, Recommendations, and Market Size
After a person reaches age thirty, he or she can expect gradual muscle tissue loss called sarcopenia to slowly set in. The term “sarcopenia,” which derives from the Latin roots “sarco” for muscle and “penia” for wasting, is the natural and progressive loss of muscle fiber due to aging. Every person aged thirty and above has sarcopenia to some degree.
Sarcopenia and osteoporosis are related and often occur simultaneously, because use of the body’s muscles provides the mechanical stress needed to put pressure on the skeletal structure and maintain bone mass. Inactivity leads to loss of both muscle mass and bone mass and can put older adults on a downward health spiral that is exacerbated by surgery, traumatic accidents, or even illnesses that cause prolonged rest.
Fat storage also plays a role in sarcopenia and thus osteoporosis as well. If muscle tissue is marbled with fat, it will be less strong than lean muscle tissue. Muscle function is inversely related to increases in intermuscular adipose tissue (IMAT), which may be just as insidious as visceral fat, the abdominal “spare tire” that increases the risk of diabetes, heart disease and early death. Excessive fat storage in muscles can be a sign of systemic inflammation. Researchers at the University of Utah’s Health Sciences Center’s Skeletal Muscle Exercise Research Facility are trying to find the connection between sarcopenia and chronic systemic inflammation, which is increasingly recognized as the root cause of all degenerative diseases.
Aging translates into a loss of muscle mass, loss of muscle function, and possible infiltration of fat into the muscle tissue. Yet the University of Utah researchers now have evidence that what we have long attributed to aging may be due to inactivity. That possibility raises interesting questions such as “is the loss of muscle mass preventable with more activity?,” and “is the loss of muscle mass reversible with more activity?” Intermuscular fat no doubt reduces strength as the fat literally gets in the way of blood vessel and nerve functions in the muscle tissue. But researchers are continuing to see if some inflammatory factor also connects IMAT and sarcopenia.
To combat the effects of sarcopenia, middle-aged adults will benefit most from a workout that emphasizes strength building and weight-bearing exercises. To combat the overall loss of energy effects with aging, adults need exercise routines that build endurance, instead of those requiring quick bursts of energy. Combining these elements would yield an exercise routine that incorporates, e.g., walking long distances (one mile or more) or using the treadmill and also some days set aside for lifting weights. Walking can maintain one’s fitness level, but walking will not enable a person to recover muscle mass from a prolonged absence of exercise due to illness or inactivity. Developing strength requires resistance training and weight-bearing exercise — not just the physical activity of walking. Strength reserves need to be built in a wellness environment.
Around age forty-five, most people first experience the onset of aging: energy levels go down, it takes more effort to do physically demanding work, and it takes longer to recover from sickness. As a whole the older population tends to neglect their bodies. It is difficult to instill a health and fitness ethic in older adults if they have not developed life-long habits of daily exercise. The best regimens will strike a balance between exercises in cardio-respiratory, endurance, strength, balance, and flexibility. The more a person ages, the more his or her body needs exercise.
The resistance exercises should target the primary muscles of the legs, trunk, and arms. Initial sessions should start out at a moderately low level of effort, with progressive increases in weight loads and difficulty over time. For those without fitness center memberships, these exercises need not require large and expensive machines as body weight, stretch cords, and dumbbells will generally suffice. Performing push ups on (carpeted) stairs at home is an excellent way to build or maintain pectoral, bicep, tricep, and shoulder muscles as well as tighten the abdominal core.
Yet despite these home conveniences, Americans do not get enough exercise and instead have a sedentary lifestyle, which is often the first step in a vicious cycle. Unless people stay active, particularly senior citizens, their joints, which already are losing their density and becoming more vulnerable to breakage over time, will grow stiffer, making movement even more difficult. Prolonged rest will also lead to a decline in aerobic capacity, and thus people become easily fatigued. People usually experience a rapid deterioration in muscle mass and energy levels in their mid-sixties.
Muscle protein production begins to slow down naturally in people when they age. Both the age at onset for muscle protein production decline as well as the rate of decline will depend on genetics as well as the level of physical activity. We know muscle fibers decline with age and that fewer muscle fibers translate into reduced muscle capacity. Thus the stage is set for muscles to become fatigued more easily and for sarcopenia.
While weight-bearing exercise is the most important treatment for sarcopenia, a recent study published in the journal Clinical Nutrition shows that the amino acid leucine may improve muscle protein synthesis and combat the onset of sarcopenia. I personally consume 4 or 5 glasses of whey protein isolate shakes (combined with water, not milk), and each 25 g scoop of whey protein isolate powder contains 2200 mg of Leucine. Drinking whey protein isolate is an effective of way of obtaining the body’s daily need for Leucine.
A 2004 study in the Journal of the American Geriatrics Society looked at sarcopenia in the United States and determined the estimated direct healthcare cost attributable to sarcopenia in the United States in 2000 was $18.5 billion ($10.8 billion in men, $7.7 billion in women). The excess healthcare expenditures were $860 for every sarcopenic man and $933 for every sarcopenic woman. The study suggested a 10% reduction in sarcopenia prevalence would result in savings of $1.1 billion (dollars adjusted to 2000 rate) per year in healthcare costs. Therefore, aging adults have both health reasons and financial reasons to take steps now to combat sarcopenia.
But companiesandmarkets.com estimated the market size of sarcopenic drug therapies to be just $10 million. The low valuation of the potential drug market comes from the fact that drug therapy is not recommended as a first-line treatment for sarcopenia. At present, no drug has been approved for treating sarcopenia. The current competitive environment comprises only generic and off-label drugs such as testosterone, estrogen, and growth hormones. There are no promising drugs in the late stages of any pharmaceutical firm’s pipeline for treatment of sarcopenia. Thus, we would not expect new drugs for sarcopenia to reach the market until after 2018. Instead, the market value for this therapeutic area will remain low due to competition from generic forms of hormones that cost as little as $20 for a monthly supply.
Yet despite that low market assessment, the pharmaceutical industry is slowly developing therapies for sarcopenia. GlaxoSmithKline, GTx, Inc., Five Prime Therapeutics, Inc., are all focused on developing selective androgen receptor modulators (SARMs), a new class of drugs with the potential to prevent and treat muscle wasting in patients with cancer, and other musculoskeletal wasting or muscle loss conditions, including chronic sarcopenia (age related muscle loss). In fact, GSK and Five Prime Therapeutics have a collaboration agreement. Similarly, Radius Health, Inc., received a patent on its SARM candidate drug. But I am most interested in Betagenon AB and Baltic Bio AB collaboration to produce a new pipeline drug (currently named “0304”) that activates AMPK, metabolizes fat as heat energy rather than storing it, and has been shown to reverse sarcopenia in lab rat experiments.