Diabetes and pig cell transplants

Insulin and diabetes

Insulin is a hormone that helps the body use sugar for energy. It is produced from clusters of cells in the pancreas called islets of Langerhans (or islets). Problems producing or responding to insulin cause diabetes.

Type 1 and type 2 diabetes

People with type 1 diabetes have no insulin-producing cells in their pancreas because they are attacked and destroyed by the immune system. The cause of type 1 diabetes is not known. Symptoms often begin in childhood and include constant hunger, thirst, passing more urine, weight loss and tiredness.

People with type 2 diabetes stop producing insulin or their cells become resistant to insulin. Type 2 diabetes is caused by obesity, poor diet and lack of exercise and often occurs in people over 40 years old. Symptoms are similar to type 1 diabetes but are less obvious, so the condition is often diagnosed after complications arise.

Diabetes in New Zealand

In New Zealand it’s estimated that over 250,000 people have diabetes. Type 1 diabetes affects about 25,000 people, whereas type 2 diabetes affects over 200,000, with thousands more believed to be undiagnosed. Diabetes affects about 5% of people of European descent and is more prevalent in Pacific (15%), Māori (10%) and Asian (8%) populations. Diabetes is the cause of about half of all heart attacks, blindness, kidney failure and lower limb amputations and a third of all strokes (Diabetes NZ, 2016).

Diabetes: a worldwide epidemic

Diabetes affects 422 million people worldwide and has been described as an epidemic. Most diabetics (about 90%) have type 2 diabetes. The incidence of type 1 and type 2 diabetes is increasing, and the World Health Organization (WHO) predicts that the number of people to die from diabetes will double between 2005 and 2030.

Treating type 1 diabetes

Type 1 diabetics will die unless they inject insulin. Type 1 diabetics monitor their blood sugar levels at least 3–4 times a day and aim to keep their blood sugar within a normal range (4–8 mmol/L). If blood sugar is too high, they inject insulin. If it is too low, they may need to eat some sugary food. This strict monitoring and treatment regime severely impacts on their lifestyle. Maintaining blood sugar in such a narrow range is difficult. Inevitably, type 1 diabetics will experience times when their blood sugar is too high or too low, and these can cause serious short-term and long-term health issues.

Effects of high blood sugar (hyperglycaemia)

• Short-term – thirst, need to pass urine, tiredness, blurry vision, dry mouth.
• Long-term – blindness, kidney failure, heart disease, nerve damage.

Effects of low blood sugar (hypoglycaemia)

• Short-term – hunger, dizziness, sweating, blurry vision, confusion and anxiety, headache, trembling or weak hands and knees, thumping heart.
• Long-term – convulsions, loss of consciousness, death.

Treating type 2 diabetes

Type 2 diabetes is largely preventable and can be managed with weight loss and regular exercise. Drugs may also be used to stimulate the pancreas to make insulin or to reduce insulin resistance. Type 2 diabetes is a progressive condition that may ultimately need to be managed by injecting insulin.

Pig cell transplants – a new treatment

LCT is developing a new treatment for type 1 diabetes. They are transplanting live insulin-producing pig cells into type 1 diabetic patients. LCT’s strategy is unique because they are using pig cells instead of human cells. Pig to human cell transplants are a type of xenotransplantation and are increasingly being investigated because of a worldwide shortage of human donor tissue. The article Preventing pig cell transplant rejection provides more information on this process.

Pig cell transplants could ultimately be used to treat people with type 2 diabetes, but more straightforward and cost-effective treatments for this disease are already available.

Benefits of pig cell transplants for patients

Clinical trials of pig cell transplants in patients with type 1 diabetes are on-going. Patients have reported needing less insulin or stopping insulin injections altogether after treatment. This significantly improves a patient’s quality of life. Another benefit is that transplanted cells keep a patient’s blood sugar within a normal range and reduce or prevent the short-term and long-term health complications of having blood sugar that’s too high or too low.

Benefits of pig cell transplants for the economy

There are significant economic costs associated with diabetes, and most of these occur as a result of health complications. In New Zealand, it’s been estimated that treating one person with diabetes can cost up to $1 million dollars over their lifetime. At this stage in development, pig cell transplants are expensive, but as the process is expanded and becomes less labour intensive, it is likely to become a relatively cheap alternative.

Other benefits of pig cell transplants

When pig cell transplants become available to the wider population, people may travel to New Zealand to have this treatment. This has been called xenotourism and is likely to bring money into the country.

Cutting-edge technologies, like pig cell transplants, are likely to raise the profile of New Zealand’s research and development and attract more investment in biotechnology.