Method of expanding and differentiating cord blood cells by hyperthermic incubation

Patent Number: 7,452,662

The stem cell compartment is part of a physiological system that responds to various stimuli.  For example, during infections, the hematopoietic stem cells produce more granulocytes to fight off the sickness, or during periods of hypoxia (such as living on a mountain), they produce more erythrocytes.  Inventors have used the physiological context of stem cells to come up with new patents.  For example, people know that stem cells prefer hypoxic niches, so patents are issued for using hypoxia to generate better neuronal stem cells.  The current patent followed this line of reasoning.

The inventors had the hypothesis that during periods of infection, there is fever, and theoretically the fever would modulate the activity of stem cells.  They found that growing CD34 hematopoeitic stem cells at temperatures higher than 37 Celsius leads to increased CD34 expansion, as well as preferential differentiation into the megakaryocytic lineage.

The first independent claim of the patent covers a means for augmenting the proliferation of nucleated cells in a population of cord blood cells that is enriched for CD34 positive cells.  This means comprises of incubating the cells in a medium that is supplemented with thrombopoietin, flt-3L, stem cell factor, and IL-6 at a temperature of more than 37 Celsius but less than 41 Celsius.  The second independent claim covers essentially similar methodology except it is a method of enriching for megakaryocytes, myeloid progenitors and platelets.   

This patent is a very good example of how lessons based on the physiology of stem cells can be translated into intellectual property.  Other patents for expanding stem cells include modification of calcium in the stem cell culture, or use of other cells that are found in the bone marrow niche.

View this patent on the USPTO website.