Monday, February 10, 2014

New stem cells easy and cheap

The production – and destruction - of human embryos to produce stem cells, with the hopes of treating degenerative diseases such as Alzheimer’s and Parkinson’s, may be moving toward irrelevancy. In a study published in the journal Nature, adult cells were induced to pluripotency with a simple proceduce to act as stem cells which were capable of transforming into varied types of cells in the body. Researchers at the RIKEN research institute in Japan, with lead study author Haruko Obokata, employed a technique referred to as stimulus-triggered acquisition of pluripotency (STAP).

Blood cells of newborn mice were soaked in a mildly acidic solution for 30 minutes, then returned to a standard cell culture medium. Those that survived this near-fatal shock were found to have been induced to pluripotency, the ability to become transformed into any type of cell in the body. Prior to this study, either embryonic cells were needed to obtain stem cells or more complicated methods involving genetic manipulation were required to induce pluripotency. The study authors noted that the technique required neither nuclear transfer nor the introduction of transcription factors. Rudolf Jaenisch, developmental biologist at the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, remarked that “It’s quite surprising” that the technique “doesn’t involve any genetic manipulation”.

A gene only present in stem cells, known as Oct-4, was tagged with a fluorescent marker after being removed from mice spleens by Obokata and her team. They found that some white blood cells exposed to mild acid stress (pH of 5.7) survived and, after two days, some of the cells began to glow, indicating they had been transformed to stem cells. These were then injected into mouse embryos and, over time, became incorporated into all three germ layers of the embryo, indicating they were inheritable. After about a week, 20% of the cells survived and, of those, 30% reverted to a pluripotent state.

Though the researchers used white blood cells from mice in the majority of the experiments, the technique was also demonstrated to be effective when used with brain, skin, muscle, and other cells. Obokata noted that the efficiency of the cells decreased with the age of the mouse, raising the need for further development of the method for use with older patients. Nonetheless, Ernst Wolvetang, stem cell scientist at the University of Queensland in St Lucia, Australia, remarked that the method is so simple that it “will make reprogramming more accessible” for widespread laboratory use.

The STAP method draws on prior research with somatic, or differentiated, plant cells which have been known to revert to an immature state when placed under certain types of environmental stress. Conditions such as insufficient water or excessive heat can cause some plant cells to become capable of forming new plants. Obokata had previously conducted studies with plants and, in 2008, began subjecting mice cells to similar stressors to determine if animal cells may react similarly.

Commenting on the study, Chris Mason, professor of regenerative medicine at University College London, stated: “If it works in man, this could be the game changer that ultimately makes a wide range of cell therapies available using the patient’s own cells as starting material – the age of personalized medicine would have finally arrived”. Furthermore, if the new STAP method works in humans, it should also reduce or eliminate the genetic mutations that can occur in induced pluripotent cells derived from embryos.

Haruko Obokata, “Stimulus-triggered fate conversion of somatic cells into pluripotency”, Nature, 505, 641-647, (30 Jan 2014).
Monte Morin, “New method makes stem cells in about 30 minutes, scientists report”, Los Angeles Times, 29 Jan 2014.
Dennis Normile, “Acid Treatment Could Provide Breakthrough Stem Cell Technique”,, 29 Jan 2014.
Lanay Tierney, “Acid bath converts blood cells to stem cells”, BioNews, 3 Feb 2014.