A fat recycling system within ‘beta cells’ in the pancreas that determines the amount of insulin the body produces could provide a target for future diabetes therapies, according to research from Sydney scientists.

The pancreas is a large organ that wraps around the gut, and produces the exact amount of insulin the body needs when a person eats — except when that person starts to develop diabetes, and insulin production slows down.

The researchers said a small structure inside the beta cell, known as a ‘lysosome’, behaves like an intracellular recycling unit. It breaks down unwanted fats and proteins in such a way that they can be re-used.

In a study published in the journal Diabetologia, PhD student Gemma Pearson and Professor Trevor Biden from Sydney’s Garvan Institute of Medical Research showed that when they prevented lysosomes from breaking down fat, beta cells secreted more insulin.

“There are many different ways fats can be used within the beta cell — so if you stop them being recycled, you force them to be used in a different way,” said Ms Pearson, whose PhD examines the “lipid profile” of beta cells.

“When you shift fats from the lysosome, you store them in other parts of the cell, and they become available to participate in various signalling pathways,” Ms Pearson said. “One of these pathways clearly increases insulin secretion,” she said.

The researchers said that while this was a “very early stage cell biology story”, it nonetheless held promise and should encourage the scientific community to “look at diabetes therapies through a fatty lens”.

“Fat molecules are not the inert blobs you might think – they can bind to proteins and activate them, causing a range of downstream events to occur,” Ms Pearson said. “The good thing about this particular pathway is that it is only stimulated by glucose. That limits the beta cell to producing excess insulin only to deal with food, rather than around the clock. Too much insulin circulating in the blood, or hyperinsulinaemia, can be very detrimental to health in many respects,” she said.

“If in future a drug were to be developed to block fat degradation in the lysosome, it would have to be tweaked to affect beta cells only,” Ms Pearson said.

The Garvan Institute of Medical Research was founded in 1963. Initially a research department of St Vincent’s Hospital in Sydney, it is now one of Australia’s largest medical research institutions with over 600 scientists, students and support staff.

Garvan’s main research areas are: Cancer, Diabetes & Obesity, Immunology and Inflammation, Osteoporosis and Bone Biology and Neuroscience.

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