Monday, March 01, 2004
Vaccine for cerebral palsy on the horizon :::::::::::::::::::::::::::::::::
In the next decade, preteen girls throughout the country may receive a vaccine designed to wipe out the majority of cerebral palsy, thanks to the work of researchers at Loyola University Chicago.
The vaccine would be given to 10-year-old girls before they are able to become pregnant to reduce the number of babies born with cerebral palsy, says Robert Mittendorf, a professor of obstetrics and gynecology at Loyola University and the lead researcher on cerebral palsy at Loyola.
Cerebral palsy is a broad term that describes a group of disorders that affect communication between the brain and muscles. Symptoms can range from mild problems with fine-motor skills, such as writing, to spastic movements and quadriplegia.
Two to three children out of every 1,000 born in this country have some type of cerebral palsy, according to the United Cerebral Palsy Association. At least 5,000 infants and toddlers and 1,200 to 1,500 preschoolers are diagnosed with cerebral palsy each year.
In all, approximately half a million people in this country have some degree of cerebral palsy.
The annual cost of caring for cerebral palsy patients is estimated at $20 billion. Many patients use wheelchairs, need assistance at home and are unable to work later in life because of the disease.
For decades, doctors and researchers thought oxygen deprivation at birth caused cerebral palsy, but Loyola researchers believe that common bacteria found next to the membranes holding the placenta at delivery may be closely linked with cerebral palsy.
The bacteria is known as coagulase-negative staphylococci and there are about 31 species.
More than half of cerebral palsy cases are attributed to inflammatory diseases caused by a "silent infection" in which pregnant women show no obvious symptoms.
The envelope of membranes around the placenta where infection-causing bacteria are found is a very small area-as thin as the space between two pieces of paper stacked on top of each other, Mittendorf says. The bacteria can travel near the membranes surrounding the placenta through the cervix from the woman's vaginal area.
The membranes can become weakened by the bacteria, Mittendorf says, and weakening of the membranes can lead to premature labor.
"Premature babies tend to have a higher risk of cerebral palsy because of the inflammatory diseases that are often associated with preterm labor and early rupture of the membranes," Mittendorf says.
Loyola researchers are following cases of women giving birth to premature babies. About 5 percent of babies weighing less than 3½ pounds will develop cerebral palsy.
"It is difficult to predict the number of cases from the [Loyola] study that may be linked to the inflammation related to the presence of these particular bacteria," Mittendorf says. "However, we suspect it could be a large number."
In the current study, researchers at Loyola are collecting a culture from near the membranes that hold the placenta in place at delivery to find out whether the harmful bacteria are present.
Infants are then kept track of for 24 months. At the end of the two-year period, the placental bacterial cultures will be compared with a cerebral palsy neurological exam of the child.
Cerebral palsy can be diagnosed as early as 15 months of age.
"Loyola is an ideal site for this study because it specializes in high-risk pregnancies," Mittendorf says.
About 7 percent of deliveries at the Ronald McDonald Children's Hospital of Loyola are infants weighing less than 3½ pounds-10 times higher than the national percentage of babies weighing so little at birth. Loyola also is the
only highly specialized health care institution with a dedicated obstetric critical care unit in Chicago.
Loyola wants to enroll 500 infants in its study and is looking at data from about 200 infants. The study is being paid for, in part, by a grant from the United Cerebral Palsy Research and Educational Foundation in Washington, D.C.
The Loyola study comes on the heels of preliminary results from a University of Chicago study, which found a "highly significant association" between coagulase-negative staphylococci cultured from the mother's placenta at birth and the later development of cerebral palsy in the child.
"If we are able to confirm the link between the condition and the bacteria, then we could focus on the development of a vaccine or antibiotics to prevent this chronic disease," says Mittendorf, who also worked on the early University of Chicago study. "That's the goal-a vaccine for all girls."
The development of such a vaccine could take 10 years because of the time needed to follow the babies in the study, followed by making the vaccine itself, animal tests and, later, human trials of the vaccine.
Susan Dodge is Ben's mother and a writer living in northwest Indiana.