Treatment - Creatine use with CMT
Question: I am a 40 year old male with CMT and have the characteristic thin lower legs. I have heard about creatine recently and was wondering if it can be used to increase the size and strength of my lower legs. Is there any information on the effects of creatine on people with CMT? Also, are there any other ways to increase the size of my lower legs? C. Jeff Schermerhorn

Dr. Mark Tarnopolsky answers: Studies of effects of creatine on muscle strength in completely healthy people have shown about a 4 % increase in high intensity muscle strength. Total mass increases by about 1.2 kg in men and 0.6 kg in women. The increase in strength in neuromuscular conditions is a bit higher, about 7 -2 %. Some CMT patients have an increase of this magnitude, however, a recent short term study (one month - funded by CMT International), did not find a significant increase in strength. After we started the study, a paper came out showing that the uptake into nerves is much slower than for muscle. Therefore, we are trying to obtain funding to do a longer term study and to combine the creatine with other agents such as CoQ10 and lipoic acid (the latter has been shown to improve nerve function in diabetic neuropathy). I am involved in a study combining exercise and creatine and we hope to get the results in a half a year or so. So the bottom line is that creatine may help with strength when taken over a longer time period, however, the increase is likely to be small, and the final studies are pending. If the CMT is mild, some have shown an increase in strength with strength training (but this should not be done with very severe end stage atrophy, and one must start slowly and under supervision).

Treatment - Nerve regeneration
Mark McCowan of Alberta, Canada sent this copy of a Reader's Digest (News from Medicine, Jan. 2001 p. 37) article to Dr. Gareth Parry asking his advice:

Nerve Regeneration
Serious accidents that damage the spinal cord and impair a patient's ability to feel and move often lead to a lifetime of disability. Until recently it was thought that damaged nerves would never regenerate. But in a study published in the journal Neuron, Samuel David, a neuroscientist, Da Wei Huang, a post doctoral fellow of McGill University, and Lisa Kerracher, a neuroscientist from the University of Montreal, report that a new vaccine can stimulate nerve growth after a spinal cord injury. The researchers focused on the myelin sheath, which insulates and wraps around the nerve fibres in the spinal cord. This myelin sheath contains molecules that inhibit nerve regeneration. Made of purefied myelin, the vaccine initiated a response in the immune systems of disabled mice, which began producing antibodies to the inhibitors in the myelin. The result was regeneration of motor neurons and the recovery of some limb function. David cautions that much work remains before a vaccine is tested on humans. -KYM Dawson in Equinox

Dr. Parry, I hope you find this item of interest. I am kind of a lateral thinker so I wondered if such a vaccine could be of use in preventing the deterioration that occurs in CMT, who knows where it might lead? However, at the moment I have little understanding of CMT other than it is an inherited genetic problem that involves nerve communication to the myelin sheath.

Dr. Gareth Parry answers: Fascinating! I was not aware of this work and I thank you for bringing it to my attention. The role of myelin-producing cells in nerve regeneration is very important. These cells also produce molecules that encourage regeneration (growth factors) so there is a dynamic equilibrium set up. In the spinal cord, there is no effective regeneration, presumably related to both production of inhibitory molecules as well as a deficiency of growth factors. In the Schwann cells that produce myelin in peripheral nerves I am not aware of inhibitory molecules occurring. However, the Schwann cells degenerate, or at least function abnormally, in CMT and the lack of the necessary growth factors may lead to secondary nerve degeneration as well as poor regeneration. This is a very exciting area.

Treatment - Growth hormones and other banned Olympic drugs helping CMT? (e.g. Erythropoietin [EPO] - endurance building and other peptide hormones)

Q: I was reading an article in the September Popular Science about drug testing for Olympic athletes. It occurred to me that some of the techniques that athletes use to enhance performance, while inappropriate for the Olympics, might be of some help to those with CMT. Examples included in the article were: Erythropoietin (EPO) - endurance building and other ‘peptide hormones.' I don't know if these techniques would be a help or hindrance to CMT patients, but it would be interesting to hear what the experts have to say about it. Gary Shepherd via e-mail.

Dr. Greg Carter answers: Good questions Gary. Indeed researchers are looking at various growth factors to help improve nerve regeneration. However, as with all things, caution must be used. Agents like human growth hormone and other growth factors may well help tissue regeneration but can also cause cancer cells to grow faster as well as other tissues that you may not want to grow. As for EPO, it can help endurance but may cause damage to the kidneys with long term use and has other serious side effects. It makes your blood thicker but can actually cause a stroke or heart attack if the blood gets too thick. Remember, if you run your car engine at high speeds all the time it will burn out faster. The same is true with the human body. Most performance enhancing drugs are ultimately fraught with long term deleterious side effects. This includes anabolic steroids, growth hormones, amphetamines and designer stimulants. However, we are making great strides at very specific types of drugs that target certain receptors and have more precise effects without the bad side effects.