Researchers Use Pig Cells For Diabetes Treatment
Diabetes mellitus is a serious disease. It affects many systems of the body. Some of the most common diabetes symptoms include excessive thirst, excessive hunger, and excessive urination. Diabetes is much more than this though. It is highly associated with heart disease and is the leading cause of nontraumatic lower limb amputations in the United States. It is characterized by high blood sugar levels that are due to lack of insulin. Insulin is made in the pancreas in a place called the Islet of Langerhans. It is the only place in the body where insulin is produced. Insulin is needed to bring glucose into body cells for energy. Without insulin, the glucose stays in the blood, bringing havoc to the body.
Studies about the effects of transplanting pig cells into the human pancreas have been going on for years, since the early 1900s. Even whole transplantation of the pancreas has been studied to alleviate the symptoms of diabetes and delay the serious complications. Until recently, studies have not been done on humans, due to several reasons. These include the complications that may be associated with transplantation and the risk associated with pig cells specifically.
Humans have been treated with insulin made from pigs for over 60 years. This is one of the reasons so many studies have included the use of pig cells for the treatment of diabetes symptoms. There are two main concerns with using pig cells. The first is that humans possess an antibody against a specific residue that is present on all pig cells. Secondly, pig cells contain a retrovirus that may infect the human being, especially if being transplanted into a human who has a low immune system, which is true for anyone undergoing transplantation of any organ or tissue to prevent rejection.
Fortunately, there are precautions that have been made to prevent many of these types of complications. The pigs that are being used in the current New Zealand study have been isolated for over 150 years, they have carried no known agent that could affect the human population, and finally, they are held in a fully closed, sterile environment. These precautions have been made specifically for those who suffer from the symptoms and complications of diabetes in order to study ways diabetes can be treated. Any risk that is present is merely theoretical. But that does not mean that these risks cannot occur.
One of the biggest concerns is rejection of the embryonic pig cells. In order to prevent rejection, the person undergoing the transplantation must have medications to stop any rejection that may occur. These medications suppress the immune system, putting the person at risk for any viruses that may be transmitted from the pig cells, or any other infectious agents the person comes in contact with. But also, there are more complications from this medical treatment of suppressing the immune system. Some of these complications include suppression of bone marrow function, mouth ulcers, deteriorating kidney function, edema, tremors, high fats in the blood, high blood pressure, weight loss, diarrhea, and fatigue. There is also a small risk for cancer. The question then weighs heavily on the person experiencing the symptoms of diabetes. Which is worse?
Only time will tell with this type of treatment for diabetes. Can the complications that come along from immune suppressant medications be resolved somehow? Does the transplantation of embryonic pig cells last long? Many studies to date have shown that any type of pig cell transplantation has only lasted for a year. Are the risks of getting a retrovirus from the pig cells really that small? It will be interesting to see the results of the new study from New Zealand. Perhaps someday transplantation of pig cells can resolve the symptoms of diabetes and delay the complications associated with such a serious disease.
The Journal of Clinical Investigation (2004)
PLoS Medicine (2006)