New Drug May Prevent Jaundice in Newborns
By TIM HILCHEY
Published: January 18, 1994
IN a development that may lead to prevention of most neonatal jaundice, researchers at the Rockefeller University in New York have developed a preventive drug that could eventually be given to all newborns.
Jaundice, the most commonly treated medical condition in newborns, occurs when bilirubin, a toxic yellow pigment, is produced faster than an infant's liver can remove it from the bloodstream, causing the skin to appear yellow. In severe cases, the buildup of bilirubin can cause damage to the brain and central nervous system.
"The importance of our studies, from our point of view, is that they demonstrate an entirely new means of addressing the problem of newborn jaundice in a preventive manner," said Dr. Attallah Kappas, a Rockefeller University researcher who led the team that developed the drug. The development is reported in the current issue of the journal Pediatrics.
Dr. Kappas said drug therapy, because it was based on the principle of prevention, might be preferable to the standard treatment, phototherapy, which is administered after the buildup of potentially harmful levels of bilirubin and requires the baby to be kept in the hospital for several days. Phototherapy involves exposure to intense light, which works by penetrating the skin and converting the bilirubin to a chemical form that is easily excreted by the liver.
The drug, tin-mesoporphyrin, or SnMP, is a chemical relative of heme, an iron-containing constituent of the red-pigmented protein hemoglobin, which is responsible for carrying oxygen throughout the body.
Dr. Jerold Lucey, who pioneered the use of phototherapy as a jaundice treatment in the United States, explained: "Babies are born with a few more red cells than normal, and their fetal hemoglobin also gradually changes to adult hemoglobin. During that process, more heme is turned over than is being metabolized, if you will, by the baby, and the baby's liver is not capable of handling the load, so that is why this yellow color builds up."
Dr. Lucey, who is also the editor of Pediatrics, explained that as the excess red cells are processed for removal from the body, heme is converted to bilirubin by the enzyme heme oxygenase. SnMP blocks that enzyme from working, and the heme is excreted from the body without being converted to bilirubin. Although only 1 to 2 percent of the roughly 3.5 million babies born each year in the United States suffer severe jaundice, Dr. Lucey said, some 75 percent of babies develop visible jaundice.
Over a four-year period beginning in 1988, the researchers conducted a randomized trial in Greece involving 517 preterm babies, among whom jaundice is common. Among those babies who received a single small dose of SnMP shortly after birth, peak bilirubin levels were reduced by 41 percent and the need for phototherapy was cut by 76 percent.