Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Penn Researchers Find Reproductive Germ Cells Survive and Thrive In Transplants, Even Among Species

16.12.2009
Reproductive researchers from the University of Pennsylvania and The Children’s Hospital of Philadelphia have succeeded in isolating and transplanting pure populations of the immature cells that enable male reproduction in two species—human spermatogonia and mouse gonocytes. These germline stem cells, taken from testis biopsies, demonstrated viability following transplantation to mouse testes within a controlled laboratory setting.

The results indicate remarkable similarity between the gene expression and behavior of the ancient cells that govern reproduction, even between two species that diverged phylogenetically 75 million years ago. The study reveals much about the lifecycle of the male germline stem cell.

The results demonstrate relevance to the basic understanding of all stem cell types—which are frequently difficult to isolate in such highly enriched populations—but also provide hope to prepubescent men risking infertility due to cancer treatment. A clinical trial using this methodology is underway at CHOP.

“There is remarkable similarity between prepubertal human spermatogonia and mouse gonocytes, which is not only very surprising but quite informative considering the large separation between human and mouse,” said Ralph L. Brinster, a reproductive physiologist at the University of Pennsylvania School of Veterinary Medicine. “In our studies we found seven of the 100 most highly enriched genes between germ cells and somatic cells were conserved in human and mice, attesting to the fundamental importance of germ cells in species evolution.”

Even when human prepubescent germ cells were transplanted into mouse testes, the cells preserved themselves by migrating to the “basement” membrane of the seminiferous tubule where they were maintained for months. The expression of several novel genes known to be essential for stem cell self-renewal was high.

The ability of prepubertal human spermatogonia to migrate to the basement membrane of mouse testes and be maintained as germ cells, and likely spermatogonial stem cells (SSCs), lends biological support to the similarity of the two species’ germ cells. The relationship opens a window of opportunity to learn about human SSCs through studies on prepubertal human spermatogonia that can be identified and isolated in essentially pure populations and relating observations to the rapidly developing information base about mouse SSCs.

The research team, led by Brinster and Jill P. Ginsberg, pediatric oncologist with The Children's Hospital of Philadelphia, published the study, “Prepubertal Human Spermatogonia and Mouse Gonocytes Share Conserved Gene Expression of Germline Stem Cell Regulatory Molecules,” Dec. 14, 2009 in the journal Proceedings of the National Academy of Sciences.

The results have particular relevance to medical treatment of human infertility because of the critical role of these stem cells in male fertility. With cure rates of childhood cancer now approaching 80, about one in 640 individuals of reproductive age are now cancer survivors. However, many of these survivors will have fertility problems as adults. Cryopreservation of a testis biopsy in a tissue bank from boys undergoing cancer therapy is an option to preserve stem cells for later transplantation to restore spermatogenesis and is currently being examined in clinical trials. The results in the paper provide valuable information relevant to handling stem cells during cryopreservation and transplantation and also establish a foundation for culture studies on the stem cells.

The Children's Hospital of Philadelphia is currently offering testicular tissue cryopreservation as an experimental treatment option. The study began in January 2008 and includes 16 boys diagnosed with various solid tumors, ranging in age from 3 months to 14 years old. All were treated with chemotherapy or radiation, which carries a significant risk of resulting infertility. These boys had a tiny portion of their testis removed and frozen for their potential future use. The hope is one day to use frozen tissue from prepubescent males to restore fertility. Physicians would thaw the preserved tissue and reimplant it in the patient's testes, or use it for other assisted reproduction technologies.

"Even though there are currently no guarantees of clinical success, families are highly receptive to this option," said Ginsberg, who led the clinical arm of the research study. Results of that study, demonstrating whether parents would be receptive to the treatment option, were published online Oct. 27 in the journal Human Reproduction.

The National Institute of Child Health and Human Development supported this study, as did the Ethel Foerderer Award at The Children's Hospital of Philadelphia, and the Robert J. Kleberg, Jr. and Helen C. Kleberg Foundation.

The study was conducted by Brinster, Xin Wu, Jonathan A. Schmidt and Mary R. Avarbock of the Department of Animal Biology at Penn’s School of Veterinary Medicine; John W. Tobias of the Penn’s Bioinformatics Core; co-investigator Jill P. Ginsberg and Claire A. Carlson of the Division of Oncology at The Children’s Hospital of Philadelphia; and Thomas F. Kolon of the Department of Urology at The Children’s Hospital of Philadelphia.

Jordan Reese | EurekAlert!
Further information:
http://www.upenn.edu

More articles from Life Sciences:

nachricht World’s Largest Study on Allergic Rhinitis Reveals new Risk Genes
17.07.2018 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Plant mothers talk to their embryos via the hormone auxin
17.07.2018 | Institute of Science and Technology Austria

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Microscopic trampoline may help create networks of quantum computers

17.07.2018 | Information Technology

In borophene, boundaries are no barrier

17.07.2018 | Materials Sciences

The role of Sodium for the Enhancement of Solar Cells

17.07.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>