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3 posts from August 2009

August 26, 2009

New insights on eye stem cells

Retinal stem cell - Wallace group Retinal stem cells have now been created from human skin, adding yet another specialized cell type to a rapidly growing list of cells that can be created using induced pluripotent (iPS) methodology. The finding could prove to be an important method in the production of human retinal cells, which would help overcome one of the greatest obstacles to successful stem cell therapies to treat eye conditions. The announcement was made on Monday by a team from the University of Wisconsin-Madison.

Discoveries such as this are important to understanding development of the human eye and understanding how eye diseases or other genetic eye conditions arise and progress. In the lab, these cells can be used to model diseases, enabling safe and rapid testing of potential drug therapies. Read SCN’s 2009 summary of current global and Canadian research to treat eye disease.

A Canadian team led by Valerie Wallace at the Ottawa Hospital Research Institute is concurrently studying better methods for controlling stem cells, so that they can coax these cells into producing different types of eye cells, such as retinal and corneal cells. They will also develop more efficient transplantation methods that help new eye cells integrate with existing tissue to restore lost vision. And they will work towards combining cells, genes, biomaterials and pharmaceuticals to create an improved artificial cornea.

Retinal stem cells were first discovered in 2000 by Derek van der Kooy at the University of Toronto.

August 12, 2009

Launch of the International Stem Cell Registry

The mission of the University of Massachusetts International Stem Cell Registry is to provide a searchable, comprehensive database that includes published and validated unpublished information on all human embryonic (hESC) and induced pluripotent (iPS) stem cell lines.

The goal is to offer current information on all known human pluripotent cell lines, including those approved by the National Institutes of Health (NIH) for federal funding and those derived through other public or private funding sources. The registry will include cell lines from non-profit institutions, academic centers, research enterprises, stem cell banks and industry based in the United States and abroad.

Check out the registry at: http://www.umassmed.edu/iscr/.

August 07, 2009

How similar are mast cells and hematopoietic stem cells?

Mast cells are cells of the immune system that play a role in inflammatory responses, such as allergies and asthma. They share a number of surface markers ("identifier" molecules on a cell that help scientists distinguish between different types of cells) with hematopoietic stem cells (HSCs). The similarity in these surface markers between mast cells and HSCs could result in mistaken identity when sorting stem cells.  This is especially relevant to HSC transplants, which are used to treat blood cancers, like leukemia and lymphoma, and blood diseases, like anemia. Since mast cells can participate in tissue repair, it is possible that some of the benefits attributed to HSC transplant may, in fact, be the effects of mast cells that are transplanted along with HSCs.

In a Journal of Infectious Diseases paper released last week, our team at the University of British Columbia compared the types of markers on both mast cells and HSCs and found a striking overlap. Many HSC markers were also expressed by mast cells, including prion protein (PrP).  PrP is what causes scrapie, bovine spongiform encephalopathy (BSE), and Creutzfeldt-Jakob disease, all of which are fatal, incurable neurodegenerative diseases. We found that PrP is a marker on the surface of mast cells, and that it is shed in a soluble form that increases with mast cell activation. Given that mast cells can cross the blood-brain barrier, they could participate in transmitting infectious prions to the brain, contributing to the way prion diseases spread.

-- Kelly McNagny, University of British Columbia