A team of Australian researchers have made an interesting discovery that could lead to a breakthrough in the type of insulin given to diabetics.
Close to two million Australians live with diabetes at a cost of $14.6 billion a year, according to Diabetes Australia. Sufferers need to regularly control their blood sugar levels which for many Type 1 and advanced Type 2 patients, involves daily insulin injections.
Associate Professor Mike Lawrence from the Walter and Eliza Hall Institute of Medical Research was involved in the research which was published this week, and tells SBS that their discovery has a rather unexpected origin in the fish-eating cone snail.
“Last year it was discovered that cone snails trap fish by squirting insulin into the water around the fish that puts the fish into hypoglycemic shock,” he explains.
“A lot of venoms are neurotoxins like snake and scorpion venom, whereas this actually functions by giving the fish a complete overdose of insulin to make the fish go into shock. The sugar is drawn out of their blood very rapidly and that makes the fish immobilised.”
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Why it's interesting:
To be effective, the insulin venom needs to work quickly to immobilise the fish that would otherwise swim away, and it’s in this fast-acting trait that the team saw the potential for human application.
“We know that one of the things that is of importance in treating diabetics is trying to get the insulin that is injected to try and work as quickly as possible so that the patient can inject as close to meal time as possible. This just simplifies the treatment, leads to greater compliance and so on,” Associate Professor Lawrence says.
Unlike the snail venom, human insulin is relatively slow releasing due in part to the so-called “hinge” segment that controls the delivery of insulin to the sites in the body where it is needed.
“It’s long been known that that hinge segment switches insulin from its storage form in the pancreas and its active form on the surface of cells. People have tried to remove this hinge but if you do that you find that the insulin doesn’t work at all.”
By analysing the snail venom structure, the team discovered that it replaces the complex eight amino acids that make up the hinge segment with a single one.
This has led them to posit that with further research, they could remove the hinge segment in human insulin and replace it with this amino acid to make it faster acting.
More to come:
This process is not that straight forward however, and Associate Professor Lawrence explains that further changes will need to be made to ensure that the amino acid is effective in the context of human insulin.
Currently, snail venom insulin is optimised to bind to fish receptors so it remains to be seen how it can be modified to bind to human receptors.
Further research and testing will be needed before this discovery can be applied to a marketable product. Associate Professor Lawrence and his team had their work published in the Nature Structural and Molecular Biology journal on Tuesday.