Yoon Bo-hyun
Professor in Department of Obstetrics and Gynecology, Seoul National University Collge of Medicine
Yoon Bo-hyun is a physician-scientist in the in the area of obstetrics and gynecology. He was the world’s first researcher to find that intrauterine inflammation plays a key role in causing not just preterm births but also fetal brain and lung disorders, such as cerebral palsy and bronchopulmonary dysplasia.
Cerebral palsy, a permanent movement disorder, affects one in every 500 babies worldwide but it hardly ever affects anyone born at Seoul National University Hospital (SNUH). In 2003, after studying the types of agents that cause intrauterine inflammation — which he found to be largely responsible for both preterm birth and infants’ cerebral palsy — Yoon Bo-hyun developed a new regimen of antibiotics and has been using it in his patients’ treatment since. “The method clearly works,” Yoon, 60, a professor at SNUH’s department of obstetrics and gynecology, said in an interview. “We have not yet found a regimen of antibiotics that works for everyone, so more research should be done. But eventually, we will get there.” Instead of using erythromycin with ampicillin or cephalosporin, a combination of antibiotics commonly prescribed for pregnant women with intrauterine inflammation, or an inflammatory condition of the uterus, Yoon said he uses ceftriaxone, clarithromycin and metronidazole. “We are trying to find the most effective ways to let the world know about our discoveries,” Yoon said. “Now we know that intrauterine inflammation is the main cause of cerebral palsy. Also, we have figured out how to detect and eradicate the cause in advance.” Given that more than three-quarters of all cerebral palsy cases are believed to occur during pregnancy, his research team’s discoveries, which demonstrate that it is possible to prevent the disorder before babies are born, will likely affect the global efforts to beat the disorder profoundly. Besides, about half of the children who develop cerebral palsy were born prematurely. Yoon said his team has found that intrauterine inflammation is responsible for 80 to 90 percent of cerebral palsy cases of preemies. Cerebral palsy happens owing to damages to the brain tissue that controls movement. Symptoms may include stiff muscles, weak muscles and tremors.
Those who have the disorder may have problems with sensation, vision, hearing, swallowing and speaking. Difficulty with the ability to think and seizure each occurs in about one third of people with cerebral palsy. Birth asphyxia, or a lack of oxygen supply to the brain during the birth process, used to be considered a leading cause of cerebral palsy. In the 1980s, however, researchers found that it is actually responsible for less than one tenth of all cases. “Researchers used to believe that asphyxia was a primary cause of both cerebral palsy and death of premature babies. However, while their death rate continued to decrease, the rate of their cerebral palsy remained flat after a certain point,” Yoon said.
“So they realized that oxygen deficiency in the brain wasn’t the only reason.” Yoon was the world’s first researcher to find that intrauterine inflammation — a concept that he also coined and introduced to the world — plays a key role in causing not just preterm birth but also fetal brain and lung disorders, such as cerebral palsy and bronchopulmonary dysplasia. Intrauterine inflammation is believed to be responsible for nearly a half of preterm births, or the birth of a baby at less than 37 weeks of gestational age. About 28,000 premature babies, representing 6 percent of the total, are born in Korea every year. Globally, the number is 15 million. “Think about a lifetime of suffering for patients and their families,” Yoon said. “Whenever I think about the number of people who will benefit from what was found at our labs, it just thrills me.”
Intrauterine inflammation is detectable and treatable
Amniocentesis used to be the only way of checking a pregnant woman for intrauterine inflammation. For the test, a needle has to be inserted through the woman’s abdominal wall, then through the wall of the uterus and finally into the amniotic sac. With ultrasound guidance, a doctor collects amniotic fluid, which shows the health condition of the uterus. But the invasive method carries risks, such as preterm labor and miscarriage, although such incidences are very rare. “Another disadvantage of amniocentesis is that it requires some expensive machinery, for tasks like ultrasound guidance, and health workers who are capable of using them. Thus, it may not benefit some people in underdeveloped countries,” Yoon said. Thus, he developed the MMP-8 rapid test, a noninvasive, more affordable method that can examine the health of the woman’s uterus accurately in 20 minutes. “The MMP-8 rapid test can show health risks of the pregnant woman quickly and easily,” Yoon said. The problem, however, is that few doctors in Korea use the test, even though it has been available since the early 2000s. Yoon noted that hospitals and doctors need to understand how important it is to conduct the test and collect data. “They could affect the lives of so many people and the future of obstetrics and gynecology by doing so,” he said. To make the test even easier and cheaper, he is developing an amniotic fluid collector made from silicone. The tool is inserted and positioned inside the vagina of the pregnant woman to collect amniotic fluid directly from the womb.
One of the most highly cited physicians in Korea
According to the National Academy of Medicine of Korea, Yoon is one of the most highly cited physicians in Korea with an h-index of 60. “I was lucky,” Yoon said. “When I became a SNUH professor in 1988, there were few Korean professors interested in the field of maternal-fetal medicine.” It was like a goldmine to the young, curious physician-scientist. A defining moment in his career as a researcher was an encounter with Professor Roberto Romero at Yale School of Medicine in the early 1990s. Romero was the first scholar who raised the possibility that intrauterine inflammation causes preterm birth. When no one took his words seriously, Yoon did. They started to work together and demonstrated that intrauterine inflammation indeed was a major cause of preterm birth and the other health issues in babies, publishing a number of articles on the topic. After Yoon returned to SNUH in the early 1990s, he started collecting research materials, such as amniotic fluid and cord blood, with consent from his patients. Over the last 24 years, he has stored the materials in freezers with providers’ information for future work. “The materials are a treasure trove for mankind,” he said. “Who knows? Cord blood might solve puzzles about some mysterious diseases like dementia or schizophrenia in the future, when the providers become old.” Nearly four decades have passed since Yoon became a doctor. “When I was diagnosed as a diabetic at the age of 29, such a long career was unthinkable to me,” he said. His condition is still serious, and he has been getting insulin shots every day since. “I have always thought that I could lose my vision or die next day,” he said. “The thought has kept me motivated and appreciative everything that I still can do.”