Scientists have recently developed the first personalized stem cells derived from a patient’s own DNA. These cells were taken from a 32-year old woman who developed Type-1 diabetes as a child, and the process signifies an important step in regenerative medicine.
The research was led by Dieter Egli, a senior research fellow of the New York Stem Cell Foundation (NYSCF). His area of specialty involves stem cells, particularly cell replacement therapy.
“This is a really important step forward in our quest to develop healthy, patient-specific stem cells that can be used to replace cells that are diseased or dead,” said Susan Solomon, chief executive officer of NYSCF.
Type-1 diabetes is a chronic disease in which the body is incapable of producing insulin due to damage of the beta cells in the pancreas. If sophisticated cell replacement therapy becomes a possible treatment plan, stem cells could create beta cells to replace the damaged ones. In theory, the patient’s body would better accept these beta cells, since they are derived from the patient’s own stem cells.
Egli’s team used a technique called somatic cell nuclear transfer to create cells specialized to the patient’s own stem cells. A nucleus from the patient’s skin cell was removed and inserted into an oocyte, an immature egg cell. The egg was allowed to grow until it became a hundred-cell embryo, called a blastocyst, and then a few of these stem cells were directed to become beta cells.
The results of this research is yet another achievement of Egli and his colleagues. In 2011, Egli’s team created embryonic stem cells with an extra set of chromosomes.
However, there are still multiple problems to be solved, such as autoimmunity, and the limited supply of oocytes. In Type-1 diabetes, the immune system will mistake the body’s failing beta cells for intruders and destroy them. It is likely that even new beta cells created with specialized cell therapy treatment will be destroyed by the patient’s immune system.
“[The problem is] where to get the oocytes,” George Church, a geneticist at Harvard Medical School says. “Human oocytes are currently precious.”
Retrieving oocytes isn’t easy–donors must undergo hormonal treatment, and egg retrieval requires minor surgery. Egli began his research at Harvard University, but was forced to relocate to New York due to Massachusetts’ restrictions regarding egg donation.
Additionally, since this treatment involves the use of human blastocysts, the somatic cell nuclear transfer technique is a topic of ethical debate. Worries have been raised that the method, or other similar types of techniques, may one day be used for human cloning or the creation of “perfect” babies.
However, there are other options out there that NYSCF is also exploring that don’t involve human blastocytes. In 2007, a team of scientists from Madison, Wis., discovered a way to create human induced pluripotent stem cells (iPS), which are similar to stem-cells, from human somatic or adult cells.
This technique is excellent for drug screening and disease modeling, but nuclear transfer may turn out to be a better choice for cell-replacement therapy. As a result, NYSCF has been funding research for both techniques.
“Too much is at stake to pick a favourite cell type yet,” Solomon said. “Our favourite is the one that will lead to better treatment.”
Stem cells could be one day used to treat not only diabetes, but diseases such as Parkinson’s and Alzheimer’s.