Tuesday, July 10, 2012

Stem cells in the ovary

Beginning about 8 years ago, scientists began providing evidence that apparently overturns the dogma that adult ovaries do not contain stem cells capable of producing oocytes.  Jonathon Tilly found such cells first in mice, then later in middle-aged women. Other labs have replicated such findings.

However, a study by members of Kui Liu's lab published today disputes that the stem cells actually produce oocytes.  Needless to say, this is stirring up quite a bit of controversy.  Tilly believes Liu was looking at oocytes, not stem cells.  Liu doesn't agree.

What does this mean for the undergraduate A&P class?  I discuss the recent discoveries of stem cells in adult ovaries in my course.  I use it as an opportunity to point out that there is still much to learn about how the human body works . . . that we are continually surprised by new research findings.  This is part of a year-long subtext of "how science works."  I tell my A&P students that I'm telling them "the last, best story" about the human body.  But that my story changes from year to year as scientists tease out more information . . . and thus revise "the story."

How does this fit in?  Well, isn't this how science is supposed to work?  Wouldn't it seem logical that it is in the best interest of everyone to have vigorous debate and extensive re-examination before we throw out the last, best story in favor of a new version?

The first article below briefly summarizes the issues involved in today's publication.

Want to know more?

Ovarian Stem Cell Debate
Ed Yong
The Scientist
(online) July 9, 2012

[Brief article discusses  that opinion is divided on a new paper showing that adult ovaries do not contain egg-making stem cells, contrary to two recent studies that appeared to overturn longstanding dogma.]

Experimental evidence showing that no mitotically active female germline progenitors exist in postnatal mouse ovaries
H. Zhang et al.
Proceedings of the National Academy of Sciences doi:10.1073/pnas.1206600109
[Recent paper disputing presence of stem cells in adult ovaries]

Ovarian Stem Cells in Humans?
Sabrina Richards
The Scientist (online) February 27, 2012
[Brief summary of recent paper by Tilly's lab stating that adult human ovaries contain a population of stem cells capable of generating immature egg cells.]

Oocyte formation by mitotically active germ cells purified from ovaries of reproductive-age women
Y.A.R. White et al.
Nature Medicine 18:413–21, 2012.
[Original research paper by Tilly's lab showing presence of stem cells in human ovaries.]

The image above is copyright free and can be used in your course!

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