A Hundred Years of Stem Cell Research

The first 100 years of stem cell research

Timeline detailing 100 years of stem cell research

The first successful bone marrow transplant between relatives can be considered the catalyst for stem cell research. Edward Donnall Thomas, often called the father of bone marrow transplantation, orchestrated the initially successful bone marrow transplant between identical twins in 1957. Although the patient later passed away due to a recurrence of leukemia, Thomas’ treatment was revolutionary. In the early 1960s, Ernest McCulloch and James Till were experimenting with injecting bone marrow into mice at the University of Toronto and the Ontario Cancer Institute. They discovered that bone marrow contained at least two types of stem cells: hematopoietic stem cells and mesenchymal stem cells. It was during this time that the two researchers also discovered transplantable stem cells. As they continued to experiment with mice, they found the injected bone marrow cells were forming colonies within the mice spleens. These colonies contained differentiated cells, which was indicative that the bone marrow cells were transplantable stem cells. 

Moving past the mid-twentieth century, in 1973, Edward Donnall Thomas performed the first bone marrow transplant between unrelated patients. A 5-year old patient from New York who was diagnosed with Severe Combined Immunodeficiency was treated with several infusions of bone marrow from a donor in Denmark. In 1978, researcher Meulen discovered that stem cells are present in human umbilical cord blood. It was observed that the number of stem cells present significantly decreased in infants 8-10 days old. This suggested that stem cells derived from umbilical cord blood should be stored as soon as possible. Irv Weissman’s lab at Stanford in the 1980s was the first to isolate stem cells. This was done using high speed cell sorters that were developed at the university. The discovery directly led to the first clinical trials in which patients received cancer free stem cells after undergoing chemotherapy. In 1981, Martin Evans, Matt Kaufman and Gail Martin isolated embryonic stem cells in mice. They unveiled that cells from early mouse embryos that were exposed to the same culture environment were able to temporarily prevent developmental progression and continue to self-renew. The following decade, in 1995, researchers at the University of Wisconsin were the first to isolate embryonic stem cells in primates, rhesus macaque monkeys. This demonstrated that embryonic stem cells could be derived from humans, as they are classified as primates. Three years later, in 1998, researchers from the University of Wisconsin and Johns Hopkins University were the first to isolate human embryonic stem cells. Their experiments were controversial: one group derived the stem cells from aborted fetuses, and the other from embryos created in a laboratory for couples seeking in vitro fertilization. 

At this point, the National Institutes of Health issued guidelines to permit federal funding of embryonic stem cell research. These were approved by former President Bill Clinton, and research continued for some time.