'Gene silencing,' immunocontraception in pipeline for nonsurgical sterilization

LOS ANGELES — A little more than a year ago, a millionaire spinal surgeon with a love for animals challenged researchers to find a viable nonsurgical method for cat and dog sterilization. He put $75 million on the table, and since then one grant has been awarded and many more proposals have been submitted, says Found Animals Foundation, the group that administers the funds. The $25 million Michelson Prize and the $50 million in Michelson Grants in Reproductive Biology (both named for the surgeon, Dr. Gary Michelson) are offered through a joint effort by Michelson's Found Animals Foundation and the Alliance for Contraception in Cats and Dogs.

"Our hope as a foundation is to support a one shot, low-cost, nonsurgical sterilization method for dogs and cats," says Shirley Johnston, DVM, PhD, who serves as the foundation's director of scientific research.

Initially declining a job offer at Found Animals, Johnston says she thought the Michelson's goal might be "impossible to achieve."

"The reason I changed my mind is, there's a lot of new exciting research out there now that wasn't around when I started working in this area," Johnston says.

Many of the proposals reviewed by Found Animals' scientific advisory board — 10 in October and maybe another 30-plus in February — deal with technology involving gene silencing or immunocontraception.

Gene silencing involves "turning off" genes that code for proteins essential in reproduction. Immunocontraception attempts to induce permanent immunity to reproduction, usually through a protein. Antibodies attack different targets like proteins and hormones in the body to stop them from working, Johnston explains. There are glycoproteins in the brain, FH and LH, and they are released under another peptide that is controlled by proteins in the brain. Antibodies along this chain, or at the level of proteins secreted by ovaries and testes, could possibly stop proteins and neutralize them so they have no effect, she says.

"People have been doing this for decades, but in previous trials it has not been permanent," Johnston adds.

Another method being proposed is the use of cytotoxins, which kill cells that can be specifically delivered to gonads and not harm other tissues.

Only one project has been cleared for funding so far, and that is research by Dr. Beverly Davison, an internal medicine professor at the University of Iowa. She is studying a gene-silencing technique to induce infertility in dogs and cats.