In an potential advance for stem cell research and cellular replacement therapies, a U.S. biotech firm says its researchers have successfully developed the first human adult therapeutic germ stem cell. Derived from adult stem cells but with the genetic characteristics of embryonic stem cells, the cells have successfully been transformed into human heart, brain, bone and cartilage cells: cardio, neuro, osteo and chondrocytes.
Therapeutically reprogrammed from germ line stem cells found in the testes of adult human males, PrimeCellTM is the first non-embryonic stem cell showing the potential to become any type of cell from any organ, something previously thought possible only for embryonic stem cells — the definition of true pluripotency. This week, the company’s researchers are scheduled to present a summary of their complete data and manuscript in a poster presentation at the Serono Symposia International’s Therapeutic Potential of Stem Cells In Reproductive Medicine conference in Valencia, Spain. PrimeGen first presented its preliminary human experimental data at the 1st International Symposium on Germ Cells, Epigenetics, Reprogramming and Embryonic Stem Cells, held in November 2005 in Kyoto, Japan.
”We have demonstrated that there’s a novel source of adult stem cells which, aside from having a role in reproduction, can be reprogrammed and used therapeutically,” said Thomas C.K. Yuen, PrimeGen chairman and CEO. “We have taken the most well-preserved, highest-quality stem cell and made it pluripotent — representing one of the most significant breakthroughs in regenerative medicine. These cells advance the potential for cellular replacement therapy for everyone.”
To form PrimeCellTM, PrimeGen extracts cells from the most protected adult stem cell source in the body — the “germ,” or reproductive, cell line, which intrinsically only can form sperm and eggs. Then, PrimeGen uses a proprietary process to reprogram the cells to become pluripotent, giving them the ability to transform into virtually any other cell type.
Because it started as a germ-line stem cell, PrimeCell retains the most conserved, highest-quality DNA generated by an organism. It suffers no damage from aging, chronic disease or injury. It is also shielded from free radical, ribosomal and mitochondrial damage — all inherent limitations of adult stem cells, until now. PrimeGen’s mouse model Proof of Concept is similar to that referenced in an article published by German researchers in this month’s issue of the journal Nature, and described in a March 24 Reuters article. But PrimeGen is further along — company researchers have already begun creating therapeutically viable cell lines from human tissue. In a paper currently submitted for peer-review, PrimeGen describes the first evidence of isolation and therapeutic reprogramming of adult human germ line stem cells into heart, brain, cartilage and bone cells.
PrimeGen obtains its human tissue samples from consenting adult males between the ages of 26 and 50. For women, PrimeGen currently is reviewing the work of Jonathon Tilly, who has shown that female germ cells exist after birth, contrary to popular belief. The company is developing a female model to attempt to reproduce the results achieved using male germ line stem cells.
”We are very pleased to see that the laboratory in Germany has independently confirmed our results — which we first described and presented in Singapore in 2005 — on the therapeutic reprogramming of post-natal germ cells,” said Francisco Silva, PrimeGen’s executive vice president of research and development, and the lead researcher for the PrimeCell initiative. “Our initial research is extremely promising and we have every reason to believe that our human PrimeCells will show true pluripotentiality, as we have observed in our mouse model.
“We’ve already been able to reproducibly differentiate heart, brain, bone and cartilage cells, and we are excited to begin testing how these cells incorporate into tissues,” Silva said. “Our goal is to create the most potent cell lines to enable the most effective treatments and therapies for as many diseases as possible. Our human PrimeCells represent a significant step in that direction.”
Pluripotent cells are required for the continued development of cellular replacement therapies designed to treat a range of life-threatening conditions, including Alzheimer’s disease, heart disease, Parkinson’s disease, diabetes, various autoimmune diseases, and some forms of cancer, among others.
PrimeGen currently is in talks with several leading physicians outside the United States who are doing cell-based therapies, to initially use the therapeutically reprogrammed PrimeCells to treat cardiac conditions. This will mark the first time in history that a germ line cell will be used therapeutically, rather than for reproduction.
From PrimeGen Biotech