Featured Research

from universities, journals, and other organizations

Testes Stem Cells Can Change Into Other Body Tissues

Date:
January 8, 2009
Source:
Stanford University Medical Center
Summary:
Scientists have succeeded in isolating stem cells from human testes. The cells bear a striking resemblance to embryonic stem cells -- they can differentiate into each of the three main types of tissues of the body -- but the researchers caution against viewing them as one and the same.

A colony of multipotent germ line stem cells obtained from a testis biopsy.
Credit: Image courtesy of Stanford University Medical Center

Scientists at the Stanford University School of Medicine and at UC-San Francisco have succeeded in isolating stem cells from human testes. The cells bear a striking resemblance to embryonic stem cells — they can differentiate into each of the three main types of tissues of the body — but the researchers caution against viewing them as one and the same.

According to the study, the testes stem cells have different patterns of gene expression and regulation and they do not proliferate and differentiate as aggressively as human embryonic stem cells.

The findings, published in the January issue of the journal Stem Cells, are in contrast to those reported in a recent Nature paper, which concluded that the cells were, in fact, as pluripotent as embryonic stem cells. Pluripotent cells can become any cell in the body and form tumors called teratomas when transplanted into mice.

"It's time to reinterpret the data," said Renee Reijo-Pera, PhD, professor of obstetrics & gynecology at Stanford, "and to accept that we're beginning to discover many different types of stem cells. Although they are all related to each other, they also all have unique therapeutic applications in which they surpass other family members."

Reijo-Pera, who is the director of Stanford's Center for Human Embryonic Stem Cell Research and Education, collaborated with male infertility specialist Paul Turek, MD, a professor of urology at UCSF and the director of The Turek Clinic in San Francisco, to conduct the research. Reijo-Pera and Turek are co-senior authors of the study.

The stem cells from the testes seem to hover in a gray area between true pluripotency and the more limited, tissue-specific multipotency exhibited by many types of adult stem cells. They termed the cells "multipotent germline stem cells." Germ cells are those cells in the body that differentiate to make sperm and eggs.

Playing to these cells' strengths — in this case, their likely ability to differentiate into cells involved in male reproduction — may be a wiser choice than trying to pigeonhole them as embryonic-stem-cell-wannabes, said Reijo-Pera.

"These cells could potentially treat infertility or other diseases in men," Turek said.

But the lure of pluripotency is strong. An easily accessible source of unmodified, pluripotent human cells would allow physicians and researchers to create cell lines and tissues identical to others in the donor's body. Theoretically such cells could be used as a perfectly matched therapy for that particular donor — perhaps to generate new cartilage to repair a knee injury or new neurons to treat nerve damage. Alternatively, the technique could be used to derive cell lines carrying specific disease-causing mutations — from a man with Parkinson's, for example—on which to conduct research.

Coaxing specialized, or differentiated, adult cells to regress back into a more malleable, embryonic-stem-cell-like state (a process called "induced pluripotency") would also allow scientists to realize the therapeutic benefits of embryonic cells without the thorny ethical problems that plague cells derived from embryos. Until recently, however, the reprogramming of differentiated cells required the use of viruses to introduce specific genes into the cells, which may limit their therapeutic usefulness.

The researchers used cells obtained via biopsies conducted to diagnose male infertility in 19 of the clinic's patients. Each patient's cells were cultured in a manner similar to human embryonic stem cells; two of the 19 samples yielded cell lines with many characteristics of the pluripotent cells. One of the two patients from whom the cell lines were derived withdrew from the study and his samples were discarded.

Further study on the remaining cell line indicated that it expressed many, but not all, genes associated with pluripotency. The cells could also be induced to differentiate into decidedly non-testicular neural cell precursors and they expressed the telomerase enzyme essential to keep pluripotent cells young and unspecialized. However, when the researchers examined the cells' patterns of methylation — a modification to DNA that affects gene expression — they found that the newly derived cell line was less-thoroughly methylated as compared to human embryonic stem cells in one region and more heavily methylated than human embryonic stem cells in another region.

Finally, when the researchers injected the human stem cells into mice with compromised immune systems, they showed only a limited ability to form a teratoma — a kind of tumor formed of many cell types. Teratoma formation resulting from the aggressive proliferation and differentiation of transplanted stem cells is a hallmark of true pluripotency. Together, the results suggest that the stem cells isolated from male testes have some, but not all the characteristics of true pluripotent cells.

"It's not yet possible to completely re-create human embryonic stem cells from germline cells," said Reijo-Pera, "These cells differ in gene expression, methylation and in their ability to form teratomas. But it's the fact that they are different that makes them so interesting. Suggesting otherwise would do a disservice to the research community by overlooking the fact that these cells are a unique cell type that could be really useful in the study of human germ cell formation."

Other Stanford collaborators on the research include graduate students Nina Kossack and Cory Nicholas; research assistant Ha Nam Nguyen; and postdoctoral scholar Shawn Chavez, PhD. The research was funded by the Gottlieb Daimler and Karl Benz Foundation, the California Institute of Regenerative Medicine and the National Institutes of Health.


Story Source:

The above story is based on materials provided by Stanford University Medical Center. Note: Materials may be edited for content and length.


Cite This Page:

Stanford University Medical Center. "Testes Stem Cells Can Change Into Other Body Tissues." ScienceDaily. ScienceDaily, 8 January 2009. <www.sciencedaily.com/releases/2009/01/090105154256.htm>.
Stanford University Medical Center. (2009, January 8). Testes Stem Cells Can Change Into Other Body Tissues. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2009/01/090105154256.htm
Stanford University Medical Center. "Testes Stem Cells Can Change Into Other Body Tissues." ScienceDaily. www.sciencedaily.com/releases/2009/01/090105154256.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) — Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) — Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) — At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) — The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:  

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile iPhone Android Web
    Follow Facebook Twitter Google+
    Subscribe RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins