Scientists at the U.S. Department of Veterans Affairs (VA) have developed a method of isolating and enriching stem cells from either bone marrow or peripheral blood which takes advantage of the non-adherent property of stem cells, as opposed to the adherent property of differentiating cells, by serially passaging the suspended cells in liquid media. The patented technology is available via patent license agreement to companies that
Common methods for obtaining human stem cells for therapeutic cell replacement include, for example, purifying cells by flow cytometry and then growing them in growth medium containing serum on a feeder layer of primate cells. The growth medium in such methods contains fetal bovine serum on the feeder layer and this makes them ill-suited for re-implanting into patients. Furthermore, double sorting CD34+ cells by flow cytometry is tedious, gives yields of low abundance, and presents sterility problems.
VA researches have addressed the above with a method to derive pure cultures of stem cells, by continuous growth in liquid culture medium in the absence of methyl cellulose, matrigel, blood clot, or other matrix. Only suspension cells are passaged by removing suspended cells and conditioned medium from stromal cells, macrophages, endothelial cells and other cells that attach to the wall of the culture flask. Suspension cells are passaged with cell-conditioned medium into fresh culture flasks containing fresh culture medium. Alternatively, the hematopoietic stem cells can be grown in defined serum-free medium.
This cell culture system yields pure populations of bone marrow stem cells, such as CD34+ or CD34− cells, in large numbers, grown in continuous cultures ,that can be expanded from microliters of cells to thousands of liters of cells. This method solves the problem of immune rejection of transplanted cells, pathogen transfer (e.g. hepatitis, HIV) from donor to host, limited availability of embryonic and fetal stem cells, and the ethical issues of human embryonic and fetal stem cells.
- Allows patients to use their own bone marrow to generate stem cells for therapeutic cell replacement which avoids immune rejection, HIV, hepatitis or other pathogen transfer and other animal virus contamination
- Obtaining abundant populations of pure CD34+ stem cells from mice would provide a rodent model to study the differentiation of hematopoietic stem cells into neurons, glia, oligodendrocytes, insulin-producing pancreatic islet cells, etc. In addition, these cells can be used in the mouse model to investigate cell transplantation for therapeutic cell replacement
- Any suitable tissue comprising stem cells may provide the original plurality of cells from which the stem cells are isolated
- The cells are grown in the absence of serum, matrix, or feeder cells, unlike the requirements of growth for human embryonic stem cells and mouse embryonic stem cells
- Businesses can commercialize the technology by licensing US patents 8,940,535 and 9,523,080 from the VA
- License fees paid to the VA are negotiable
- Businesses that license the technology may have the opportunity to pursue collaborative research with the inventors
- Testing data may be available to companies evaluating the technology
- TechLink guides businesses through evaluation and licensing; services provided at no cost
- VA ID: 03-166