St Vincent’s Hospital Melbourne is now offering a life-changing procedure to patients with type 1 diabetes which allows them to produce their own insulin, dramatically reducing their risk of hypoglycaemic events.
The procedure involves transplanting islet cells from a donor pancreas into the patient’s liver where they begin to produce insulin, stabilising the patient’s blood sugar and in many cases eliminating the need for daily insulin injections.
According to St Vincent’s transplant physician and nephrologist, A/Prof David Goodman, around 130,000 Australians live with type 1 diabetes, a condition that destroys the pancreas leaving sufferers unable to produce insulin. These patients must adhere to a strict diet, test their blood sugar levels with multiple finger pricks each day and rely on injections to give their body the insulin it needs to function normally.
‘Many patients with type 1 diabetes suffer regular hypoglycaemic events – commonly referred to as hypos – caused by dangerously low blood sugar levels,’ explains A/Prof Goodman. ‘Symptoms include palpitations, tremors and sweating. If the low blood sugar is not corrected, the patient may pass out or suffer a seizure.
‘Hypos are unpredictable and can be extremely dangerous,’ he continues. ‘Some patients develop ‘hypoglycaemic unawareness’. Their body bypasses normal symptoms to progress quickly to unconsciousness and without intervention they risk coma or even death. You never know when a hypo will come on and there is no way to test for it. As a consequence, many patients with type 1 diabetes require someone with them around the clock.’
Islet transplantation was first trialled in Canada in 2000 at the University of Alberta Hospital.
St Vincent’s conducted the first islet cell transplantation trial in Australia in 2007, in collaboration with the St Vincent’s Institute and the Tom Mandel Islet Transplant Program, funded by the Australian Government and the Juvenile Diabetes Foundation.
Six years on, the procedure is now part of clinical practice with two to three patients receiving an islet transplant each year.
The patients are given two transplants at three months apart and they are monitored closely for signs of insulin production.
‘The results at three months start to show increased levels of glucose control – fewer highs and lows.
Importantly, they are also showing evidence of the vital C-peptide, a product of insulin synthesis, which has been entirely absent prior to the transplant in these patients.
The presence of C-peptide is evidence of a successful transplant,’ A/Prof Goodman says.
‘Some 50 per cent of our islet transplantation patients are still off insulin up to five years after their procedure.
But perhaps the most important outcome is that the hypos simply melt away after the first transplant.
This is a major change of life for these patients.’ St Vincent’s now has a purpose-built islet isolation facility where a team of scientists conduct the painstaking work of extracting islets from donor organs.
‘It takes two or three scientists around eight hours to isolate the islets and examine them carefully.
They are extracted the same day as the organ is donated, with a view to transplanting them within
24–48 hours,” A/Prof Goodman says.
Each donated pancreas yields around 250,000 to 300,000 islets. The islets are put into a culture overnight, and patients are asked to come into hospital the following morning.
The procedure is conducted under light anaesthetic, using a small incision near the patient’s naval. The islets are transplanted into the liver, as it is more accessible, and because a diabetic patient’s pancreas has been destroyed by the immune system.
Patients are first given immunosuppressive drugs which take several hours to infuse prior to the transplant, and will remain on anti-rejection drugs for life.
‘You can watch the islets transfer as they are as big as poppy seeds. The idea is that they will stick to the periphery of the liver and start making insulin,’ explains.
Patients remain on their insulin pumps and continue to be tested at four, six and twelve weeks post-transplant.
‘Over that time we are generally decreasing the insulin dose through their pump. We then look to do another transplant in about three months,’ A/Prof Goodman says.
Islet transplantation is now an accepted government funded therapy for type 1 diabetes and St Vincent’s is part of the Nationally Funded Centre program.