Placental precursor stem cells require testosterone-free environment to survive

October 29, 2009

Tampa, Fla. (Oct. 29, 2009) - Trophoblast stem cells (TSCs), cells found in the layer of peripheral embryonic stem cells from which the placenta is formed, are thought to exhibit "immune privilege" that aids cell survivability and is potentially beneficial for cell and gene therapies. Further, the survivability of TSCs has been thought to require the presence of ovarian hormones. However, none of these assumptions has ever been verified. This study, published in the current issue of the journal Cell Transplantation (18:7) - now freely available on-line at http://www.ingentaconnect.com/content/cog/ct - has demonstrated that it is the absence of male hormones, rather than the presence of female hormones, that allows extended transplanted cell survivability.

"Questioning whether a female hormonal environment is one of the physiological requirements for ectopic TSC survival, we surmised that a partially immune-privileged site other than the uterus might also allow TSCs to survive and exert a protective action on other nearby cells, enabling the latter to survive in locations where they normally could not," said Dr. Bert Binas, co-author of the study.

When the research team injected the livers of both male and female mice with TSCs, the cells survived in female animal livers but did not survive in male animal livers.

"This was not unexpected, given the natural uterine environment for TSCs," said Dr. Binas. "However, castration of the male mice abolished the sex hormone difference and the livers of the castrated male mice provided a perfect environment for the TSCs."

The researchers concluded that the presence of male hormones was toxic for the injected TSCs. The injected TSCs survived for three months with little if any proliferation, regardless of their immunological compatibility, but were dependent on a non-male hormonal environment in castrated male mice.

The TSCs were also found to promote survival of another cell type when transplanted together, suggesting that these cells may be able to modify their local environment and enhance the survival of co-transplanted cells. Thus a new "stem cell based trophoblastic approach" to therapeutic cell transplantation may prove to be beneficial.

"Our model provides a starting point for systematically assessing the hormonal and other physiological requirements for trophoblast cells in vivo," concludes Dr. Binas and his colleagues.

This study, for the first time, demonstrates that long term survival of trophoblast cells in the absence of ovarian hormones is possible.

"These are exciting results and clearly show that the relationship of stem cells with the host or transplant recipient includes a complex interaction between the 'seed and the soil'," said section editor Dr. Stephen Strom, professor in the Division of Cellular and Molecular Pathology at the University of Pittsburgh. "In the case described here, the "soil" or the natural female environment free of male hormones is an appropriate and supportive environment for TSCs, whereas, the presence of the male hormones proved quite unfavorable for the sustained engraftment of the cells.The good part is that this paper demonstrates that cells such as TSCs confer immunoprotection to another cell type when co-transplanted with the TSCs. However this benefit is only extended to female recipients - males need not apply".
-end-
The editorial offices for Cell Transplantation are at the Center of Excellence for Aging and Brain Repair, College of Medicine, the University of South Florida and the Diabetes Research Institute, University of Miami Miller School of Medicine. Contact, David Eve, PhD. at celltransplantation@gmail.com or Camillo Ricordi, MD at ricordi@miami.edu

News Release by Randolph Fillmore, Florida Science Communications.

Cell Transplantation Center of Excellence for Aging and Brain Repair

Related Stem Cells Articles from Brightsurf:

SUTD researchers create heart cells from stem cells using 3D printing
SUTD researchers 3D printed a micro-scaled physical device to demonstrate a new level of control in the directed differentiation of stem cells, enhancing the production of cardiomyocytes.

More selective elimination of leukemia stem cells and blood stem cells
Hematopoietic stem cells from a healthy donor can help patients suffering from acute leukemia.

Computer simulations visualize how DNA is recognized to convert cells into stem cells
Researchers of the Hubrecht Institute (KNAW - The Netherlands) and the Max Planck Institute in Münster (Germany) have revealed how an essential protein helps to activate genomic DNA during the conversion of regular adult human cells into stem cells.

First events in stem cells becoming specialized cells needed for organ development
Cell biologists at the University of Toronto shed light on the very first step stem cells go through to turn into the specialized cells that make up organs.

Surprising research result: All immature cells can develop into stem cells
New sensational study conducted at the University of Copenhagen disproves traditional knowledge of stem cell development.

The development of brain stem cells into new nerve cells and why this can lead to cancer
Stem cells are true Jacks-of-all-trades of our bodies, as they can turn into the many different cell types of all organs.

Healthy blood stem cells have as many DNA mutations as leukemic cells
Researchers from the Princess Máxima Center for Pediatric Oncology have shown that the number of mutations in healthy and leukemic blood stem cells does not differ.

New method grows brain cells from stem cells quickly and efficiently
Researchers at Lund University in Sweden have developed a faster method to generate functional brain cells, called astrocytes, from embryonic stem cells.

NUS researchers confine mature cells to turn them into stem cells
Recent research led by Professor G.V. Shivashankar of the Mechanobiology Institute at the National University of Singapore and the FIRC Institute of Molecular Oncology in Italy, has revealed that mature cells can be reprogrammed into re-deployable stem cells without direct genetic modification -- by confining them to a defined geometric space for an extended period of time.

Researchers develop a new method for turning skin cells into pluripotent stem cells
Researchers at the University of Helsinki, Finland, and Karolinska Institutet, Sweden, have for the first time succeeded in converting human skin cells into pluripotent stem cells by activating the cell's own genes.

Read More: Stem Cells News and Stem Cells Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.