T2D drug helps with type 1 diabetes

RESEARCHERS at the Garvan Institute have discovered that metformin, a drug typically used in type 2 diabetes, reduces insulin needs in type 1 diabetes, opening the door for improved management of the condition.

Doctors have long prescribed metformin off-label to treat insulin resistance in type 1 diabetes, based largely on anecdotal evidence.

But a new clinical trial led by the Garvan Institute of Medical Research has found that metformin does not counteract insulin resistance in type 1 diabetes – however, it reduces the amount of insulin needed to maintain blood sugar levels in the ideal range.

The researchers pointed out that managing blood sugar levels with insulin is mentally and physically demanding, with long-term use of insulin leading to insulin resistance in some people.

This in turn requires people to use ever-increasing amounts of insulin to keep blood sugar levels under control.

“Insulin resistance is a growing problem in type 1 diabetes,” said endocrinologist and study co-lead Dr Jennifer Snaith.

“Not only does it make regulating blood sugar levels difficult, but it is an underappreciated risk factor for heart disease, which is one of the biggest causes of health complications and deaths in those with type 1 diabetes,” she explained.

The team randomised 40 adults with long-term type 1 diabetes to take either metformin or a placebo for six months, then examined whether their insulin resistance changed over that time.

Unexpectedly, the team found that the use of metformin did not lead to improvements in insulin resistance or changes to blood sugar levels, suggesting that unlike for type 2 diabetes, metformin does not work to counter insulin resistance in type 1 diabetes.

However, metformin decreased the amount of insulin people needed to keep their blood sugars stable by 12%.

“This is an important result,” said Dr Snaith.

“Insulin is a relatively old treatment which, while lifesaving, comes with significant mental and physical burden [and] lowering the amount of insulin used is a priority for many people living with type 1 diabetes,” she continued.

“We have shown that a very cheap, accessible medication may serve this purpose and this is very exciting,” she concluded.

The team is now looking into a potential mechanism for metformin’s effect in type 1 diabetes, with the gut microbiome an initial target for investigation.

“There is increasing evidence suggesting that metformin may act on the gut [which] is why we are now investigating how metformin changes gut flora, also known as the microbiome, in people with type 1 diabetes,” said Dr Snaith.

“We’re hoping this will provide clues on metformin’s mechanism of action, so that it can be more widely used in the management of type 1 diabetes,” she added.

The study was published today in Nature Communications HERE. KB