Muscle wasting and its prevention

Brand new article (Gould et al., 2012) has reported the molecular mechanisms that lead to skeletal muscle wasting from cancer treatment. This process is often called cancer cachexia. Cancer cachexia is most prominent in metastatic/advanced stage cancers, cancers of the digestive organs, or after treatments that impair major hormones like testosterone, estrogen, or thyroid. In my work, the most common example I've seen is androgen deprivation therapy for prostate cancer.

The Gould article was again one I could only see the abstract for, so I found another by Al-Majid & Waters (2008) to help shed some light on the subject for me.

Some tumor cells can produce a protein called proteolysis-inducing factor (PIF). PIF inhibits muscle cells from synthesizing protein to replenish themselves, let alone grow more muscle. Additionally (and they know less about exactly how this one works), cancer patients experience an increase in muscle protein degradation. So not only does cancer stop muscle from building, it actively rips it away.

Al-Majid & Waters (2008) supposed, and Gould et al (2012) showed that resistance exercises like lifting weights can reduce or even reverse cancer cachexia. While I don't have access to the details of it, what makes the Gould article so important is they were able to observe and described the molecular mechanisms of how exercise reversed cancer cachexia.

Why is all this important? The loss of muscle has three major effects:

1. Without sufficient muscle mass, cancer treatments either become ineffective or too toxic for the body
2. Loss of muscle mass leads to decreased functionality
3. Loss of muscle mass decreases metabolism

So the take home message is that any cancer survivor who is at risk for cancer cachexia should engage in an appropriate hypertophy style resistance training program. 

Citations:

J Cachexia Sarcopenia Muscle. 2012 Dec 13. [Epub ahead of print] 

Cancer cachexia prevention via physical exercise: molecular mechanisms.

Gould DW, Lahart I, Carmichael AR, Koutedakis Y, Metsios GS.

 

Al-Majid & Waters (2008) The biological mechanisms of cancer-related skeletal muscle wasting: the role of progressive resistance exercise, Biol Res Nurs, 10, 7-20.