This patent covers the inhibition of placental growth factor as a method of treating osteoporosis. The one issued claim is restricted to inhibition of placental growth factor using an antibody or fragments of the antibody.
The inventor demonstrated inhibition of bone resorption in an animal model, as well as in vitro using anti-placental growth factor antibodies. Interestingly in the examples the use of mesenchymal stem cells together with this antibody are also described.
The desire to expand hematopoietic stem cells is not only a basic research accomplishment but would allow for widespread use of autologous stem cells, as well as expand the utilization of cord blood stem cells which are usually of concern due to the relatively low stem cell content.
Dr. Clarke's group previously demonstrated that the polycomb gene Bmi-1 is essential for hematopoietic stem cell renewal (Park et al. Bmi-1 is required for maintenance of adult self-renewing haematopoietic stem cells.
Nature. 2003 May 15;423(6937):302). Subsequently other groups have demonstrated that Bmi-1 is involved in adult but not embryonic stem cell self-renewal. One of the mechanisms by which Bmi-1 maintains self-renewal is by suppressing the cell cycle inhibitors p16Ink4a (p16) and p19Arf (p19). This is very interesting since both of these genes have been demonstrated to be accurate biomarkers of aging ! (Krishnamurthy et al. Ink4a/Arf expression is a biomarker of aging. J Clin Invest 114:1299).
In the current paper, Dr. Clarke generated mice that lack p53 as well as p16 and 19. Interesting these mice has a ten fold increase hematopoietic stem cells capable of reconsituting other repients. Additionally this striking increase in hematopoietic stem cell activity was correlated with increased cells expressing the surface phenotype of early hematopoietic stem cells.
This finding is of great interest since it suggests that techniques such as RNA interference may be useful in "suppressing suppressors" of stem cell self renewal and thus allowing for the generation of novel methods of expanding autologous stem cells without inducing differentiation.
Student Society For Stem Cell Research - www.ssscr.org
SSSCR
Student Society For Stem Cell Research
We believe that stem cell research will revolutionize the field of medicine. With a coordinated and cooperative global effort, we can advance stem cell research in the most efficient manner.
