RESEARCHERS DEVELOP REVOLUTIONARY NEW TECHNIQUE OF  DEVELOPING STEM CELLS

       Scientists at the University of Cambridge have for the first time shown that it is possible to derive from a human embryo a new type of stem cell - one of the most flexible types of stem cell, which can develop into human tissue.

Potentially revolutionary in regenerative medicine, the technique could open up new avenues of research into disorders such as Down's syndrome. Although the ability to derive pluripotent stem cells has been possible for over thirty years from mouse embryos, this is the first time this has been possible from human embryos.

Human pluripotent stem cells for use in regenerative medicine or biomedical research come from two sources: embryonicstem celss, derived from fertilised egg cells discarded from IVF procedures; and induced pluripotent stem cells, where skin cells are reprogrammed to a flexible, reprogrammable form, which may make it easier to direct them into any cell type of interest.

"Until now it hasn't been possible to isolate these naïve stem cells, even though we've had the technology to do it in mice for thirty years - leading some people to doubt it would be possible," explains Ge Guo, the study's first author, "but we've managed to extract the cells and grow them individually in culture. Naïve stem cells have many potential applications, from regenerative medicine to modelling human disorders."

These stem cells have no restrictions on the types of adult tissue into which they can develop, which means they may have so much possibility in medical science and  therapeutic uses in regenerative medicine to treat.

condtions that affect various organs tissues, particularly those that have poor regenerative capacity, such as the heart, brain and pancreas

Dr Jenny Nichols, joint senior author of the study, says that one of the most exciting applications of their new technique would be to study disorders that arise from cells that contain an abnormal number of chromosomes. Chromosomal abnormalities cause intellectual and mental challenges such as Autism, Mental Retardation etc.

"Even in many 'normal' early-stage embryos, we find several cells with an abnormal number of chromosomes," 

explains Dr Nichols. "Because we can separate the cells and culture them individually, we could potentially generate 'healthy' and 'affected' cell lines

.This would allow us to generate and compare tissues of two models, one 'healthy' and one that is genetically-identical other than the surplus chromosome.

 This could provide new insights into conditions such as Down's syndrome.

"Meanwhile, Kejin Hu, Ph.D., of the University of Alabama at Birmingham, has found a robust reprogramming factor that increases the efficiency of creating human induced pluripotent stem cells (HiPSCs) from skin fibroblasts more than 20-fold, speeds the reprogramming time by several days and enhances the quality of reprogramming.

Man-made versions of human embryonic stem celss, these can help biomedical researchers generate HiPSCs from many somatic cells such as fibroblasts from a skin biopsy, without destroying any human embryo. 

In a paper published March 7 in Nature Communications, Hu and fellow UAB researchers describe their successful hunt for a reprogramming factor that boosts the efficiency and shortens the time the cell takes to reprogram.

In another paper published at the same time in Stem Cells and Development, Hu's lab reports a promising solution to an issue associated with the clinical application of human iPSCs.

"We suggest," the authors write, "that the antibody could be employed to eliminate the tumorigenic pluripotent cells in human PSC-derived cells for cell transplantation."

PODXL is known to be involved in more than 10 different human malignancies and has a reported role in metastasis and tumor invasion. Hu's laboratory is interested in finding whether the same antibody can kill other malignant cells in cancer patients.