Type 1 Diabetes - is a Vaccine in Sight for this Costly Disease?
Published: 13 June 2017
Published: 13 June 2017
Whilst many of the complications associated with type 1 diabetes (T1DM) can be avoided, there is poor insulin management amongst sufferers – known as ‘psychological insulin resistance’.
Defined as “psychological opposition towards insulin use among both people with diabetes and healthcare providers” (Gherman et al, 2011), this resistance to treatment is down to a variety of reasons, including:
Research has been conducted for a number of decades into alternative treatment types for replacing the lost insulin, such as insulin pumps, however they still rely on patients being compliant with treatment. In some cases, insulin pumps are only available to a minority of sufferers – such as young children who may not be able to comply with an injection regime.
An ideal alternative would be to block the immune cells from attacking the pancreas, whilst leaving the rest of the immune system untouched – but immunosuppressants would leave sufferers more vulnerable to infection.
A vaccine seems to be the most promising solution – and something a number of research teams have been working on. Although vaccine research and development is taking place around the world, and has been for quite a while, so far there have been mixed results.
The Pre-Point early vaccination entered its second clinical trial in October 2016.
The vaccine took the form of powdered insulin administered orally with food, to children aged between two and seven. Believing that T1DM may be prevented by sensitising the immune system to insulin (which is often the first target of the autoimmune response causing the condition), the trial administers the vaccine to children identified as having high risk of developing diabetes, and a positive immune response had been observed in the first stage.
Another promising vaccine study lies with the research funded by Bayhill Therapeutics.
This study was carried out by a team of researchers from Europe, the US, and Australia, looking into improving the function of the insulin-producing beta cells of the pancreas.
Rather than looking at the auto-immune response as a whole, they believe that targeting one of the pathways for diabetes development would yield better results.
Insulin is made in stages – starting with an immature form called pre-proinsulin, which is made and secreted by the beta cells. The body processes it into proinsulin, and finally into insulin. Previous research on mice had shown that injecting a ring of DNA, called a plasmid, could prevent and reverse the destruction of the beta cells by CD8+ T cells. T cells are the immune cells responsible for targeting and destroying beta cells.
For this clinical trial, the researchers injected trial participants with a plasmid containing the DNA code for making proinsulin. By artificially introducing the proinsulin through the vaccine, researchers believe that the immune system could become more tolerant to it. As a result, the immune system would be far less likely to react to the naturally occurring proinsulin, and the beta cells creating it.
The trial compared the effects of the vaccine against the placebo in just 80 people, but found that it did improve the function of the insulin-producing beta cells within the pancreas. However, the effects appeared to be temporary as the functioning of the beta cells declined soon after the regular vaccine injections stopped. How long the vaccine can last for will be the subject of future clinical trials.
This vaccine alone seems unlikely to stop all beta cell destruction, or restore all function. As the destruction caused by the auto-immune response occurs through several routes, it’s likely that a number of vaccines or other approaches will be needed. However, it certainly shows promise that vaccines can be developed as a means of treating, or indeed preventing, T1DM, and a larger study involving 200 younger people with the disease is planned for the near future.
It’s unlikely that a vaccine will be available for use within the next few years, however the research findings from the clinical trials are positive. We’re gaining a far deeper understanding of T1DM, and as such the potential for alternative treatments is great. In the meantime, it’s essential that resistance to using insulin is reduced as much as possible through patient and professional awareness and education.
Over 1.7 million Australians are affected with diabetes (Diabetes Australia, 2015), with an estimated 10% having Type 1. T1DM is an auto-immune condition, where the immune system attacks the pancreatic cells that make insulin.
Without insulin, there is no regulation of glucose levels in the blood, the glucose can’t be turned into energy and so the body burns its own fats as a substitute.
Not only does this cause fatigue, weight loss, and blurred vision but it also causes chemical substances to be released into the blood. Without ongoing injections of insulin, these substances accumulate and can cause a life threatening condition called ketoacidosis.
The effects of Type 1 diabetes can be far reaching and costly.
There are more than 4,400 amputations per year in Australia as a result of diabetes, and in 2005 more than 1000 people died as a direct consequence of foot ulcers and lower limb wounds (Australian Institute of Health and Welfare, 2008). Experts have estimated that diabetic foot disease alone costs Australia around $875 million every year.
Add to that the cost of diabetic macular oedema leading to vision loss (occurring in over 15 per cent of Australians with diabetes according to Bayer Australia Ltd, 2015) – more than $28,000 per person. When other complications such as heart disease, stroke, nerve damage, and kidney disease are added to the mix, the yearly cost is quite staggering.
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