Recruitment of various progenitor cells into injured tissue is a well known phenomena. For example, after infarct, mobilization of bone marrow stem cells into the injured myocardium has been reported. The current patent uses G-CSF, a cytokine that stimulates hematopoiesis and causes mobilization of stem cells, to chemoattract fibroblasts to injured myocardium. It is known that fibroblasts secrete numerous growth factors, which is one of the reasons why they are used as feeder cells for embryonic stem cells. In fact, an interesting publication reported that fibroblasts also have antiinflammatory/immune suppressive activities similar to mesenchymal stem cells. Ironically, the patent covering this, #7,491,388, is owned by Osiris, the company that is using mesenchymal stem cells in Phase III clinical trials for graft versus host disease.
The one independent claim of the current patent is:
"A method for recruiting fibroblast into a heart in need thereof, which comprises administering granulocyte colony-stimulating factor (G-CSF) in an amount sufficient by itself to recruit fibroblast into said heart"
Dependent claims include specific cardiac conditions, formulations of G-CSF and concentrations of G-CSF.