Adenoviruses threaten viability of embryos destined for womb.

2002 NOV 14 - (NewsRx.com & NewsRx.net) -- by Sonia Bell-Nichols, senior medical writer - Viruses commonly used in gene therapies may threaten the viability of embryos that undergo certain manipulations, according to a new U.S. study.

The in vitro fertilization (IVF) business has grown exponentially in the past decade. So has the exploration of gene therapies incorporating delivery vehicles, or vectors, comprising common adenoviruses that can infect humans. Scientists say certain manipulations that open the protective layer (zona pellucida) of an embryo or oocyte prior to its implantation in the womb could lead to its infection by adenovirus and potentially harmful consequences.

"Such interactions could lead to toxic effects on the embryo or to insertion of foreign genes into the germ line," speculated J.W. Gordon, the leader of an investigation at Mt. Sinai Medical Center in New York City, New York.

A mouse model study has revealed that adenovirus-infected embryos may be likely to die following adenoviral exposure. Researchers evaluated the murine embryos for extended periods after their exposure to adenovirus vector, recording viability, cytotoxicity, and other growth characteristics.

"These vectors exerted no deleterious effects until after the 2-cell stage, where they caused developmental delay and disorganized cleavage," said Gordon.

Infectious particles were more toxic to the embryos than were ...