June 14, 2008
Pigs Replace Mice in Search for Cure Clues
CYSTIC FIBROSIS Cystic fibrosis is the most common genetic disease in Caucasians. The median life span for those with this malady is 36 years, and lung disease is the major cause of mortality. For years, scientists have studied cystic fibrosis using mice in which the cystic fibrosis gene was altered. However, mice do not develop lung disease like humans with cystic fibrosis.
Researchers at the University of Missouri, Columbia, and the University of Iowa, Iowa City, have taken the first step in developing a porcine cystic fibrosis model that may more closely mimic the disease in humans. "When you make the same genetic mutations in mice that people have, mice don't get the lung disease that's associated with cystic fibrosis, so no model currently exists to research lung disease caused by cystic fibrosis," explains Randy Prather, distinguished professor of reproductive biotechnology in the UMC College of Agriculture, Food and Natural Resources.
"Compared to mice, pigs may be a good model for human genetic diseases because their anatomy, biochemistry, physiology, size, and genetics are more similar to those of humans."
To create the genetic defect in pigs, a team led by Michael Welsh from Iowa's Howard Hughes Medical Institute made genetic modifications in the animals' cells. Prather's group then generated the genetically modified pigs from the cells using a method called nuclear transfer. With the genetic modifications, the researchers hope they will be able to mimic the lung disease that afflicts humans who have cystic fibrosis.
"The gene that is mutated in individuals with cystic fibrosis was discovered in 1989; yet, we still do not understand many aspects of this disease and our treatments remain inadequate," Welsh laments. "Although scientists and physicians have learned much from studying cystic fibrosis mice, to make progress and improve treatments, we need an animal that at least partially mimics the lung disease of humans.
"We also are working with other researchers who are doing similar work with ferrets. We hope that these first steps will ultimately provide scientists with the means to better probe cystic fibrosis and aid those who suffer its ravages. We have our fingers crossed that these animal models will be of help."