Islet Cell Transplantation: Can It Facilitate Insulin Independence?

Author(s): 
By Jessica Kaylor, BA, and John S. Steinberg, DPM

Weighing The Pros And Cons Of Islet Cell Transplantation

Islet cell transplantation, on the other hand, involves one surgical procedure usually performed with a local anesthetic, and can result in self-production of insulin by the recipient’s system for up to five years.3 The minimally invasive nature of this surgical option is preferred over the more elaborate procedure of total pancreatic transplantation. In addition to establishing possible insulin independence for a number of years, islet cell therapy may help control glycated HbA1c and decrease the recurrence of hypoglycemia.4    Although current literature expresses optimism about the validity of islet cell transplantation as a solution for glycemic control, researchers are also realistic about the current limitations of this therapy. Significant advances are needed in order for this treatment course to become widely available and successful in establishing normaglycemia.    The limited availability of donor islet cells and the rejection of these transplanted tissues by the recipient’s immune system are the two most serious challenges to islet cell transplantation. Approximately 1 million islet cells are needed for transplantation to be successful. As a result, two or more donors are usually needed per recipient, thus limiting the availability of ample transplantation material. The extraction process itself is relatively inefficient as well and contributes to the difficulty of obtaining islet cells for recipients.    After the islet cells are collected and transplanted into a recipient, the patient’s immune system often attacks the foreign islet cells. Researchers have developed a method using contrast agents and magnetic resonance imaging (MRI) to assess the degree of rejection of the transplanted cells, and determine the success of the transplant.5 Beta cells of the pancreas, which are responsible for the production of insulin, are particularly at risk for attack by the immune system as well as by infectious agents or toxic materials involved in diabetes mellitus type I.6 As a result, one would use immunosuppressant drugs in tandem with islet cell transplantation to minimize rejection of foreign cell material which, in turn, hampers the patient’s ability to fight infection and disease.    Another unfortunate and ironic result of immunosuppressant therapy is the decreased function of the recipient’s own limited supply of islet cells. Radical pharmaceutical developments are needed to create immunosuppressant drugs that act only to assist in the acceptance of donor islet cells instead of suppressing the recipient’s entire immune system.    Researchers have utilized gene transfection, or the injection of foreign DNA into a cell to alter its properties, to strengthen beta cells’ defense from an attack on the immune system.6 We need a better clinical understanding of how cells protect themselves from attack by the immune system before this technique can significantly increase the effectiveness of beta cell replacement.6 An additional concern is the fact that immunosuppressive therapy negatively impacts renal function. Accordingly, this therapy would be limited to those with healthy kidneys.

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