Stem cells lines that avoid immune rejection created

December 21st, 2007 - 4:17 pm ICT by admin  

Washington, Dec 21 (ANI): Scientists have advancement in s tem cell studies by creating human embryonic stem cell lines that avoid immune rejection in large segments of the population.

The stem cell lines are HLA-homozygous, meaning that they have a simple genetic profile in the critical areas of the DNA that code for immune rejection.

According to scientists from International Stem Cell (ISC) Corp, these lines could serve to form a stem cell bank as a renewable source of transplantable cells for use in cell therapy to replace damaged tissues or to treat genetic and degenerative diseases.

This study has used a novel approach to producing cells that may one day be used to treat large numbers of patients. While there is a great deal of discussion about the possibility of producing stem cells for each patient this approach to therapy is unrealistic because of the enormous costs involved, said Ian Wilmut, PhD, journal Editor-in-Chief and Director of the Centre for Regenerative Medicine at the Queens Medical Research Institute, University of Edinburgh.

Rather it is likely that treatment of large numbers of patients by cell therapy will only be possible if methods are found using any one cell line to treat very large numbers of patients. This very exciting paper represents a significant step forward towards the use of such cells in cell therapy.

Immune reaction is one of the most serious problems facing the development of stem cell therapy, and cell lines of this type may enable us to treat a large number of patients without immune rejection, offering an enormous practical advantage. Further research is required to confirm that the cells produced in this way are able to replace cells that have been lost in human degenerative disease, he added.

Jeffrey Janus, President of International Stem Cell and colleagues at the company and from the Russian Academy of Medical Sciences, described the successful parthenogenetic activation of human oocytes and the subsequent derivation of cell lines having the morphology and markers characteristic of human embryonic stem cells.

In a paper entitled, HLA Homozygous Stem Cell Lines Derived from Human Parthenogenetic Blastocysts, the authors highlight two key factors that would make this technology so valuable for future efforts to create replacement tissues and organs and to use donor-derived cell repositories to develop cell-based therapies.

First, the four human parthenogenetic stem cell lines, designated as HpSC-Hhom, are HLA (human leukocyte antigen) homozygous. This makes it possible to match the HLA types of a donor and recipient, reducing the chances of provoking an immune reaction against the transplanted donor cells.

Second, the stem cells are derived from unfertilized donor eggs, not from fertilized embryos, so the technique does not carry the same ethical burden.

The authors say that the future clinical relevance of this work will depend on the ability to reproduce these results and to show that the stem cell lines can be induced to form pluripotent progenitor cells and, ultimately, to differentiate into specific mature cell types that can be safely and successfully delivered to patients.

The study is published in Cloning & Stem Cells. (ANI)

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