Stem cells and their use in transplantation

Patent Number: 7,537,756

The problem with islet transplantation is that one needs 2-3 pancreatic donors per recipient, and even this high number of islets still end up eventually being rejected/nonfunctional.  Additionally the recipient needs to be on immune suppression.  These drawbacks are not only because of allogeneic issues, but also due to poor vascularization once the islets are injected via the hepatic portal vein. 

The current patent teaches the use of expanded donor islets prior to transplantation.  Specifically, the first claim covers:

A method of treating a patient with diabetes mellitus, comprising the steps of:

(a) isolating a nestin-positive pancreatic stem cell from a pancreatic islet of a donor;

(b) culturing the stem cell ex vivo to produce a progenitor cell; and

(c) transferring the progenitor cell into the patient, wherein the progenitor cell differentiates into an insulin-producing beta cell, wherein the patient does not serve as the donor for said stem cells of step (a); thereby treating said patient with diabetes mellitus.

The patent is interesting because in the dependent claims they also cover the use of xenogeneic islets.

Unfortunately the issue of immune suppression or en masse generation is not addressed.  Some believe that the more immature state of expanded islet progenitors would reduce requirements for immune suppression.  This patent would be interesting to compare to other IP on islet precursors such as the work of Ammon Peck. 

View this patent on the USPTO website.