Judith Staerk: Stem cells from your blood
Human blood cells – taken at doctors’ offices or hospitals – can now be reprogrammed into a state like embryonic stem cells, according to researchers.
Judith Staerk: You erase the memory of the blood cell, and you bring it back to a state where there is no memory, and you can tell that cell to become skin, or a neuron, or a blood cell.
Judith Staerk is lead author of a study released in July 2010. She’s with the Whitehead Institute of Biomedical Research in Cambridge, Massachusetts. She and her team discovered how to insert reprogramming genes into a blood cell – genes that function to erase the cell’s “memory” of being a blood cell and cause it to act more like an embryonic stem cell. Embryonic stem cells are key to many disease studies because they can generate all types of cells in the human body. This research might help avoid the ethical issues of harvesting stem cells from embryos.
Judith Staerk: Basically, I go to the doctor, and he withdraws 20 milliliters of my blood, and I can directly use those blood cells.
She said once a blood cell has been reprogrammed into a stem cell, scientists can make copies of it and use them to study diseases and new medicines. A patient’s own cells, stored in a hospital blood bank, may explain the cause of their disease – even after death.
Judith Staerk: We can retrospectively go back, and look on a DNA level, for example, if there was a genetic reason for the disease.
Staerk explained that the type of stem cell she helped create is called an induced pluripotent stem cell, or iPS cell. Pluripotent means the cell is capable of becoming many different types of cell. That’s like an embryonic stem cell.
Judith Staerk: An embryonic stem cell can give rise to every cell type in the human body. It can give rise to blood, to skin, to neurons, everything.
These iPS cells are different from adult stem cells, which are thought to become only cells in the tissue they originated from – for example, an adult stem cell from skin is currently believed to be limited to generating different types of skin cells. She said up until now, skin cells – obtained from skin biopsies – were the main source for iPS cells.
Judith Staerk: It’s easier to get blood drawn – that’s a five minute procedure – than a skin biopsy, which requires local anesthesia, and incisions and stitches. So more people would be willing to have blood drawn than having a skin biopsy taken.
She said the potential problem with these stem cells from skin and blood is that scientists don’t know if they are able to erase the cell’s entire memory of being a skin or blood cell. Staerk said that if there is “memory” left in the cell, that could interfere with the cell’s ability to be truly like an embryonic stem cell.