Introduction:
The pancreas is a vital organ located in the abdomen, behind the stomach, and in front of the spine. Its main functions include the secretion of juices that aid digestion, and the production of two important hormones, insulin and glucagon, that help regulate blood glucose levels by helping the body’s cells use glucose to produce energy.
The pancreas consists of clusters of cells called islets of Langerhans. Islets have different types of cells, out of which special cells called beta cells produce insulin. Islet cell transplantation is a procedure in which beta cells are transferred from a donor pancreas into a person with type 1 diabetes to prevent the need for daily shots of insulin injections. The transplantation procedure is still being carried out experimentally.
What Is the Relation Between Type 1 Diabetes and Insulin?
Diabetes is when the body does not make enough insulin or cannot use the insulin produced. It is a chronic condition in which uncontrolled blood sugars can cause many complications, affecting the eyes, nerves, heart, and kidneys.
Type 1 diabetes is an autoimmune condition in which the body’s immune system destroys the beta cells, leading to a deficiency of insulin in the body. Around five to ten percent of people in the US (United States) diagnosed with diabetes are those with type 1 diabetes. The condition is not inherited, and neither is there a way to prevent it. Insulin deficiency makes patients with type 1 diabetes take multiple insulin shots daily and regularly check blood sugar levels.
Patients receive insulin therapy in the form of insulin injections or pumps. However, despite a planned treatment and continuous monitoring of the glucose levels, people with type 1 diabetes experience episodes of high to low sugar levels, making it difficult to manage also, the risk of developing long-term complications increases due to altering blood sugar levels.
What Is Hypoglycemic Unawareness?
Some people with diabetes, who try to maintain their blood sugars at optimal levels, can experience frequent episodes of hypoglycemia. When a person starts experiencing hypoglycemia, they have some warning signs and symptoms that help them recognize it. However, recurrent episodes of hypoglycemia can make people go into hypoglycemic unawareness. As a result, they do not have any signs of hypoglycemia, thereby making it a life-threatening condition. These episodes, when left unrecognized or untreated, can be serious.
What Is Islet Cell Transplantation?
Islet cell transplantation is a procedure in which beta cells from a deceased donor are transplanted into people with type 1 diabetes. After transplantation, the beta cells start making insulin, reducing the need for daily insulin injections.
Special enzymes help remove beta cells from the donor. To be effective in the recipient, people receiving the transplants require around 10,000 islet cell equivalents from two donors.
How Is Islet Cell Transplantation Performed?
A radiologist performs the procedure. First, the patient is given a local anesthetic and a sedative. A small plastic tube called a catheter is inserted through the upper abdomen into an important vein called the portal vein of the liver. Then the islets are infused into the vein through the catheter. Sometimes, a surgeon may also do the procedure by infusing the donor’s cells into the recipient’s liver after giving a small incision under general anesthesia. After implantation, the beta cells start to produce and release insulin into the body.
What Are the Benefits of Islet Cell Transplantation?
The goal of transplantation is to improve the patient’s quality of life and reduce recurrent episodes of low blood sugar. Successful transplantation has the following benefits that include:
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An improvement in the regulation of blood glucose levels. The need for frequent monitoring of blood sugars and multiple daily shots of insulin injections is minimized. In very few patients, the need for daily insulin injections can be eliminated. Though in most patients, the need for insulin injections is reduced for only a few months to years, the frequent bouts of low sugar episodes decrease for a longer time.
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Reasonable control of blood glucose levels also reduces the risk of long-term complications involving the heart, eyes, nerves, and kidneys.
What Are the Risks Involved in Islet Cell Transplantation?
Along with benefits, the procedure also has some involved risks that include:
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Rejection of the new cells as the body’s immune system considers any cell that is not a part of the body as “foreign” and tries to destroy it. To counteract this, doctors advise using immunosuppressive or anti-rejection medicines that lead to severe side effects. Also, few researchers believe that long-term use of immunosuppressive medications can increase the risk of infections and a few types of cancers.
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Formation of blood clots or bleeding after surgery.
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Lack of available pancreas donors.
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The need to receive two to three transplants to achieve complete insulin independence.
What Are the New Immunosuppression Protocols?
The research was started for islet cell transplantation in the 1960s. The first transplantation was done in 1990, with a success rate of 8 percent. The success rates have increased with time due to improved and better anti-rejection medicines. The “Edmonton Protocol” has introduced a new combination of anti-rejection medicines that include Daclizumab (Zenapax), Tacrolimus (Prograf), and Sirolimus (Rapamune). Daclizumab is given immediately after the transplant intravenously (IV) and then stopped. Tacrolimus and Sirolimus are medicines that are to be taken lifelong. However, the drugs have side effects, which include:
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Mouth sores.
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Diarrhea.
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High blood pressure.
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High cholesterol levels.
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Tiredness.
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Decrease in WBC (white blood cell) count.
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Decreased kidney function.
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Increased susceptibility to infection.
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Increased risk of developing cancers.
Researchers are trying to develop new drugs or modify the combinations of already developed medications to improve the chances of better acceptance of the islet cells. If successful, it can help patients maintain the new cells in the body without requiring long-term immunosuppression. A recent study is also developing islet cells with a special coating that prevents rejection.
Who Are Eligible for the Transplantation?
People with type 1 diabetes who have had it for more than five years are considered for transplantation in the age groups of 18 to 65 years. Also, those who have repeated low sugar episodes or an increased risk of developing complications related to diabetes, like kidney failure, are eligible for the procedure.
Conclusion:
Islet cell transplantation is a field that gives hope to patients with type 1 diabetes. However, as any procedure has its benefits and risks, so does islet cell transplantation. Research is going on to improve the success of the procedure. The main aim is to prevent the rejection of the islet cells and reduce the side effects. Also, the number of recipients in need of transplantation is more when compared to the available donors. Therefore, studies and testing are in progress to obtain islet cells from a live person’s pancreas or other animals. A successful transplant can help people with type 1 diabetes lead a better quality of life with a lesser need for insulin shots, constant monitoring of blood sugars, and long-term diabetes-related complications.
