Depression, Depressionen

Vagus-Nerv-Stimulation (VNS):

High-dose Vagus Nerve Stimulation Does Not Cause Teratogenicity in Animals

Because most epilepsy treatments are taken daily on a long-term basis by persons who are otherwise healthy, understanding the risk of teratogenicity is a major concern. All antiseizure medications currently available are teratogenic, especially at high doses. This preclinical study assessed the teratogenicity of VNS Therapy in New Zealand white rabbits. Ten female adult rabbits implanted with the VNS Therapy device were given a typical human dose of 1mA stimulus intensity, 30 seconds on alternating with 5 minutes off. Comparing body weight, this dose is about 14 times greater than a human would receive. Serving as control groups, ten additional rabbits were implanted with nonfunctional VNS Therapy devices, and four others were not implanted. All of the animals were mated. Half of the animals were euthanized at midgestation, and the remaining half at 1 week after birth of the litter. Uterine contents were examined grossly and histologically. The evaluation found no differences on any reproductive parameter between the group that received active VNS Therapy, the group implanted with nonfunctional devices, and the group that was not implanted. Aspects evaluated included mating behaviour, required number of matings, viable and dead foetuses, litter size, weights of individual kits, weights of organs, and relative organ weights. Histological assessments of selected tissues, including neural tissue, did not show any changes or abnormalities in the rabbits that received VNS Therapy. The overall conclusion was that VNS Therapy does not affect the fertility of or cause teratogenicity in this standard animal model.

Toxicon Corporation of Bedford, Massachusetts, conducted this study and conformed to all applicable laws and regulations.

Source: Cynthia L. harden, MD Comprehensive Epilepsy Center, Weill Medical College of Cornell University, New York, NY.