Mutated mitochondria could hold back stem-cell therapies

[HuckleB]

Stem cells derived from older people may need to be screened before use in therapies.
http://www.nature.com/news/mutated-mitochondria-could-hold-back-stem-cell-therapies-1.19752

"Induced pluripotent stem cells (iPS) — those derived from adult cells — are inching closer to the clinic. But as a new study helps to show, much work remains before the field can yield mainline treatments.

The older a patient is, the more likely it is that induced pluripotent stem (iPS) cells derived from them will carry genetic mutations that could affect the cells’ function, researchers report in Cell Stem Cell1. These mutations are found in the DNA of mitochondria, organelles that power the cell and have their own genomes. Each cell can contain hundreds of mitochondria.

To test how genetic variations in mitochondria might affect iPS cells, a team led by reproductive biologist Shoukhrat Mitalipov at Oregon Health and Science University in Portland collected skin and blood samples from a 72-year-old volunteer. The scientists sequenced DNA from the samples, then transformed the adult cells into stem cells by infecting them with viruses that cause the expression of several genes involved in early embryonic development.

When the researchers isolated and sequenced DNA from the resulting stem cells, they did not find a high rate of mutations in the mitochondria overall. But when they examined DNA from individual cells chosen at random, they found a wide variety of mutations in mitochondria that had been obscured in the larger pool of cells.

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