A 'fountain of youth' for stem cells?

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A 'fountain of youth' for stem cells?

http://www.eurekalert.org/pub_releases/2009-12/ctco-ao122809.php

Tampa, Fla. (December 28, 2009) – Researchers from the University of Hong Kong

and the Massachusetts Institute of Technology have published a study in the

current issue of Cell Transplantation (18:9), now freely available on line at

http://www.ingentaconnect.com/content/cog/ct, that explores ways to successfully

keep stem cells " forever young " during implantation by slowing their growth,

differentiation and proliferation.

" The successful storage and implantation of stem cells poses significant

challenges for tissue engineering in the nervous system, challenges in addition

to those inherent to neural regeneration, " said Dr. Ellis-Behnke, corresponding

author. " There is a need for creating an environment that can regulate cell

activity by delaying cell proliferation, proliferation and maturation.

Nanoscaffolds can play a central role in organ regeneration as they act as

templates and guides for cell proliferation, differentiation and tissue growth.

It is also important to protect these fragile cells from the harsh environment

in which they are transplanted. "

According to Dr. Ellis-Behnke, advancements in nanotechnology offer a " new era "

in tissue and organ reconstruction. Thus, finding the right nano-sized scaffold

could be beneficial, so the research team developed a " self-assembling nanofiber

scaffold " (SAPNS), a nanotechnology application to use for implanting young

cells.

" Fine control of the nanodomain will allow for increased targeting of cell

placement and therapeutic delivery amplified by cell encapsulation and

implantation, " explained Dr. Ellis-Behnke.

The research team created the scaffold to provide a substrate for cell adhesion

and migration and to influence the survival of transplanted cells or the

invasion of cells from surrounding tissue. The SAPNS they developed appear to

slow the growth rate and differentiation of the cells, allowing the cells time

to acclimate to their new environment.

" That delay is very important when the immune system tries attacking cells when

they are placed in vivo, " he further explained.

By manipulating both cell density and SAPNS concentration, the researchers were

able to control the nanoenvironment surrounding PC 12 cells (a cell line

developed from transplantable rat cells that respond to nerve growth factor),

Schwann cells (glial cells that keep peripheral nerve fibers alive) and neural

precursor cells (NPCs) and also control their proliferation, elongation,

differentiation and maturation in vitro. They extended the method to living

animals with implants in the brain and spinal cord.

The researchers concluded that the use of a combination of SAPNS and young cells

eliminated the need for immuno-suppressants when cells were implanted in the

central nervous system.

" Implanted stem cells are adversely susceptible to their new environment and

quickly get old, but this study suggests a solution to conquer this problem, "

said Prof. Shinn-Zong Lin, professor of Neurosurgery at China University Medical

Hospital, Taiwan and Chairman of the Pan Pacific Symposium on Stem Cell Research

where part of this work was first presented. " The self-assembling nanofiber

scaffold (SAPNS) provides a niche for the encapsulated stem cells by slowing

down their growth, differentiation and proliferation, as well as potentially

minimizing the immune response, thus enhancing the survival rate of the

implanted stem cells. This allows the implanted stem cells to " stay forever

young " and extend their neurites to reach distant targets, thereby

re-establishing the neural circuits

This combination of stem cells and SAPNS technologies gives a new hope for

building up younger neural circuit in the central neural system. "