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March 10, 2011

Biomaterials for the Feeder-Free Culture of Human Embryonic Stem Cells and Induced Pluripotent Stem Cells

Scientists at a Taiwan university have achieved a breakthrough in cell rejuvenation by injecting four genes into a mature cell, which resets the cell's bio-clock to a state similar to fertilization They managed to induce fibroblast cells to split into pluripotent stem cells, which are similar to embryonic cells.

Chemical Review - Biomaterials for the Feeder-Free Culture of Human Embryonic Stem Cells and Induced Pluripotent Stem Cells



The technique involves opening up the membrane of a mature cell so that it accepts four genes -- Oct4, Sox2, Klf4 and c-Myc -- which work like "a key to the source of life, " explained Ling Qingdong, director of the Cathay Medical Research Institute.

Once the mature cell's bio-clock has been reset by the genes, the cell becomes rejuvenated, reverting to the state of newly fertilized cell, Ling said.

The beauty of this technique is that there is an infinite supply of cells and the four genes do not have to be carried by viruses in order to alter the mature cells, he said.

"We are calling it a breakthrough because there is no danger of contamination by viruses, " Ling said. "Furthermore, we don't have to use embryonic cells and therefore will not invite ethics debates."

However, Higuchi said his team has only been able to achieve a 0.3 percent to 1 percent success rate. This means that only three to 10 of every 1,000 mature cells were successfully converted into multi-purpose stem cells, he said, adding that improvement would be needed.

In spite of the low success rate, the authoritative Chemical Review published the research report in its current online issue, saying the technique had good prospects.

The research team also reported that it has designed a method to quickly collect stem cells, a technique that it said may some day be used to help treat leukemia.

The method uses a cubic-structured, nano-meter cell membrane that can filter and collect stem cells in 1/10 of the usual time, Higuchi said.

This technique also helps speed the growth of cultured stem cells by at least six times the normal rate, he said.

Stem cells from umbilical cord blood are not in high supply and the faster they are collected the more slowly they age, according to Cathay General Hospital Vice President Hung Kun-lung.

Therefore, Higuchi's quick collection technique means the cells could multiply faster in culture and may one day help develop a cure for people suffering from leukemia and other diseases, he said.

Higuchi said he was working on another project to extract stem cells from fat tissues, a technique that he said would mature in about five years time.

By that time, "we might be able to induce stem cells to grow as myocardium or heart muscle cells, which would be beneficial to people with ischemic heart disease," he said.

Journal of Clinical Gerontology and Geriatrics - Induced pluripotent stem cells and regenerative medicine

Stem cells, a special subset of cells derived from embryo or adult tissues, are known to present the characteristics of self-renewal, multiple lineages of differentiation, high plastic capability, and long-term maintenance. Recent reports have further suggested that neural stem cells (NSCs) derived from the adult hippocampal and subventricular regions possess the utilizing potential to develop the transplantation strategies and to screen the candidate agents for neurogenesis, neuroprotection, and neuroplasticity in neurodegenerative diseases. In this article, we review the roles of NSCs and other stem cells in neuroprotective and neurorestorative therapies for neurological and psychiatric diseases. We show the evidences that NSCs play the key roles involved in the pathogenesis of several neurodegenerative disorders, including depression, stroke, and Parkinson’s disease. Moreover, the potential and possible utilities of induced pluripotent stem cells, reprogramming from adult fibroblasts with ectopic expression of four embryonic genes, are also reviewed and further discussed. An understanding of the biophysiology of stem cells could help us elucidate the pathogenicity and develop new treatments for neurodegenerative disorders. In contrast to cell transplantation therapies, the application of stem cells can further provide a platform for drug discovery and small molecular testing, including Chinese herbal medicines. In addition, the high-throughput stem cell-based systems can be used to elucidate the mechanisms of neuroprotective candidates in translation medical research for neurodegenerative diseases.

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