VITAMIN C HELPS MICE WITH CMT1A

High doses of ascorbic acid (vitamin C) can improve or stabilize motor function in mice with a particular form of Charcot-Marie-Tooth (CMT)disease, say researchers in France, who published their results in the April issue of Nature Medicine.

Edith Passage and Jean Chretien Norreel of the Institut National de la Sante et de la Recherche Medicale (Institute of Health and Medical Research) in Marseille gave high doses of ascorbic acid to mice with CMT type 1A.

The human form of CMT1A usually results from a duplication in the gene for peripheral myelin protein 22 (PMP22) on chromosome 17, with overproduction of the PMP22 protein. It’s this type of PMP22 defect that the researchers reproduced in the mice used in these experiments.

In addition to the improved function, they found evidence that the ascorbic acid may have reduced PMP22 overproduction and thereby normalized the formation of myelin, a sheath that surrounds nerve fibers and helps signals move through the nervous system. The effect may be specific to the type of CMT that results from PMP22 overproduction.

The investigators say they plan to begin clinical trials of vitamin C in CMT1A in the near future, but they urge caution for the present.

“Regarding clinical trials of vitamin C (ascorbic acid) in CMT1A, one must keep in mind that a molecule is not a medicine,” said Michel Fontes, who was on the study team. “We do not know if ascorbic acid works in humans and what the optimal dose is.” Fontes went on to say that mice differ from humans in that they synthesize ascorbic acid, while humans do not.

He also expressed concern that if enough patients begin taking large doses of vitamin C on their own, it might be impossible to do a study to find out if it really works and what its toxicity might be.