Dr. John David Gearhart, a pioneering scientist who worked in stem cell research to find treatments for Parkinson’s and Alzheimer’s diseases, died of cancer May 27 at his home in Swarthmore, Pennsylvania. He was 77 and had lived in North Baltimore.
While at the Johns Hopkins School of Medicine, he became known for identifying and isolating human embryonic stem cells.
“He had a unique approach, and his discoveries are the reason we are going to be able to cure horrible diseases,” said a Hopkins colleague, Dr. Roger Reeves of Millersville. “In 50 years we will be crediting him for his work with Alzheimer’s, spinal cord injuries and Parkinson’s.”
He was born in Homer City, Pennsylvania His father, Robert Fulton Gearhart, a coal miner, died when he was a child. He was raised by his mother, Pauline Brillhart Gearhart Angelo, and her husband, George Angelo. He and a brother were sent to Gerard College in Philadelphia, whose students included many orphans. He grew up on a farm and became curious about horticulture and later about botany. His interests included the pigmentation of flower petals and the genetics of lilacs. Family members said he was fascinated by the flora of the Allegheny Mountain region.
He earned a bachelor’s degree at Pennsylvania State University and a master’s degree at the University of New Hampshire, then a doctorate from Cornell University.
In 1964 he began studying the role of stem cells and genetics in plants, animals, and humans. He was on the staff of the Institute for Cancer Research in Philadelphia in the 1970s and came to Baltimore as an assistant professor of anatomy at the University of Maryland School of Medicine.
In 1980 he joined the Johns Hopkins School of Medicine and initially studied Down syndrome.
He led a research team that first identified and isolated human embryonic stem cells in 1998.
The Baltimore Sun reported that year, “Scientists at the Johns Hopkins School of Medicine and the University of Wisconsin said yesterday that they had separately reached a potential milestone toward growing human tissue for transplantation.
“The researchers, reporting in two journals, said they had used different methods to grow colonies of embryonic stem cells — parent cells for every tissue in the human body,” the article said. “Both teams acknowledged that the work, although exciting, is likely to ignite a debate over the source of the cells: aborted fetuses in Baltimore and unused embryos in Wisconsin.”
“The potential of these unique, versatile cells for human biologic studies and medicine is enormous,” said Dr. Gearhart, who was then a professor of obstetrics and gynecology and led the Hopkins effort. “We assume that they can form virtually every cell in the body.”
He spent his scientific career championing the ethical use of embryonic stem cells for eventual transplant and regenerative therapies.
“I will point out that these cells in a dish do not represent a human being and that the future of these cells would have been just to be discarded,” he said in a Sun interview. “We can now make tremendous use of them first through cell-based therapies that just a few years ago were not on the radar screen.”
He also said, “Some people argue that this research puts us on a slippery slope, that someday scientists could encourage women to have abortions or couples to create embryos so they may be used therapeutically. There’s a misconception out there that there is a market for embryos, that people are going to be selling embryos.“
He said that “the [ethical] bar here is extremely high. I could show you what it took for us to get approval for this type of work. There is no way you’re going to see trafficking, money exchanging hands. There is a federal law saying you cannot traffic. It is a criminal offense.”
Dr. Gearhart often testified before Congress and federal agencies about stem cells.
In a 2006 Sun article, while a member of a Food and Drug Administration panel, he said, “These days you try to anticipate, especially in this field because of the increased sensitivity and the fact this stuff is really novel.”
“My father, later in his career, was driven to teach students about the implications of scientific discovery on modern society,” said his daughter, Sarah Vater of Jersey City, New Jersey. “His foremost concern was that scientists would learn to communicate their discoveries in a way that avoided alienation and misrepresentation.”
His daughter also said, “In tandem to his determined career as a scientist, he was an ever-present and adoring father to me and my sister. He gave us unwavering encouragement and insight throughout his life.
“My father enjoyed his gardening and his yard work,” said his daughter. “He would find respite in the outdoors. It all started when he was training in botany. He loved to cook and read. He read all the time. His idea of a great place to visit was Longwood Gardens.”
In addition to his daughter, survivors include another daughter, Elizabeth Fisher of Newtonville, Massachusetts, and two brothers, Donald Gearhart of Uniontown, Pennsylvania and Gary Gearhart of Blairsville, Pennsylvania. His marriages to Shannon Fisher and Patricia Faust Gearhart ended in divorce.