Cerco Medical’s patented thin-sheet immunobarrier system is expected to permit transplantation of islets without immune suppression drugs by protecting the islets from host rejection, while enabling nutrients such as oxygen and glucose to migrate freely in and out, respectively, and allowing insulin produced by the islets to migrate freely out through the immunobarrier.
The Islet Sheet is populated with islets obtained from organ donors that restore the bodies ability to produce insulin that was destroyed by autoimmune attack on the beta cells (insulin secreting cells) in the diabetic’s own pancreatic islets. The cells in the Islet Sheet respond to changing blood sugar levels with the release of insulin in real time, mimicking the normal function of pancreatic islets.
The Islet Sheet is comprised of three components: islets, a reinforcing mesh to give strength and durability and highly purified alginate, which completely encapsulates the other two components. Configured as a thin sheet only 0.3 millimeters thick, with outside dimensions of 4 centimeters x 6 centimeters, the Islet Sheet is expected to be about the size of a business card. A central core region containing islets suspended in alginate and the reinforcing mesh are surrounded by and bonded to acellular immuno- protective alginate layers. Islets are kept alive by diffusion of oxygen, glucose and other nutrients into the sheet. The sheet is so thin that passive diffusion alone supports islet life and function. Islets in the sheet (figure at right) maintain stable blood sugars by secreting insulin in response to changing blood glucose and other blood constituents including amino acids.
The Islet Sheet surface is mirror-smooth on the cellular scale and made via a proprietary process that results in highly purified and biostable alginate. The reinforcing mesh is 80% open to allow diffusion of nutrients. The mesh serves as an anchor by which the Islet Sheet may be sutured into the proper location.
Alginate purified from sea kelp is readily available commercially or from cultured kelp. The Company has developed proprietary methods for alginate purification and processing resulting in alginate gels with the specific properties required for the Islet Sheet, including purity and molecular permselectivy and biostability.
The Cerco Medical thin-sheet device (figure to right) has a central zone with islets (light center rectangle in the figure) and a surrounding cuff for suturing. It incorporates several design improvements over competing approaches which shall be evaluated out in clinical studies.
These improvements include:
there is no foreign body response
the sheet is fully retrievable, ensuring safety
the sheet is replaceable
thinness permits sufficient oxygen diffusion and ensures cell viability
immuno-isolation prevents destruction of islets by immune processes
thin-sheet technology is compatible with many different cell lines
glucose and other nutrients into the sheet. The sheet is so thin that passive diffusion alone supports islet life and function. Islets in the sheet (figure at right) maintain stable blood sugars by secreting insulin in response to changing blood glucose and other blood constituents including amino acids.
