'Good Cholesterol' helps people with diabetes heal

Good cholesterol could help protect diabetics from heart disease complications and limb amputations that impact the lives of thousands of Kiwis each year, new research has revealed.

A newly-published study by The Heart Research Institute has found for the first time that high-density lipoprotein (HDL) cholesterol, which is believed to help guard against heart disease, may also stimulate new blood vessel growth in people with diabetes.

“Diabetics have reduced ability to form new blood vessels, putting them at risk of life threatening vascular complications, so to be able to find a potential solution to this problem is very exciting,” says HRI researcher Dr Christina Bursill.

“With this discovery we have possible new therapies that could spare them the life-threatening complications and debilitating amputations that many people with diabetes will face.”

The findings are published today in the international journal Diabetes.

More than 240,000 adult New Zealanders live with diabetes, a disease where your body cannot control its blood sugar levels properly, either because the body doesn’t produce insulin or has become resistant to it. Diabetics have difficulty in forming new blood vessels that are essential for wound healing and for tissue regeneration following a heart attack.

“As a result they don’t recover quickly from complications associated with impaired healing and are more likely to have limbs amputated or have a higher risk of having a heart attack,” explains Dr Bursill.

“There have been significant advances in treatment of vascular diseases but sadly 20-30 percent of these patients do not respond well to current therapies and this is largely due to complications associated with diabetes. New treatments for diabetics are desperately needed.”

The HRI’s Immunobiology Group has previously discovered that HDL can promote new blood vessel formation in healthy bodies. In the new study the team set out to investigate whether good cholesterol could also increase blood vessel formation in diabetics, where the stimulation of new blood vessels is really needed.

They tested the hypothesis in the laboratory to see the effects of HDL on a wound and a vessel blockage in the leg similar to those experienced by diabetics. Using laser imaging and tissue analysis, researchers were able to check for new blood vessel growth.

“We found that HDL, whether delivered intravenously or by local application onto a wound, restored new blood vessel formation to levels seen in healthy models,” Dr Bursill says. “This led to increased blood flow in the leg and accelerated wound closure.”

The study also investigated the intracellular mechanisms of how exactly HDL rescues impaired new blood vessel formation in diabetes, which may lead to future development of novel therapeutic agents, the researcher say.

Associate Professor Martin Ng from he Heart Research Institute and co-author said, “These findings also highlight a new pathway for the translation of HDL, which until now, has been focussed on reducing advanced plaque formation in the vessels of the heart”.

The Heart Research Institute now hopes to take the work into a clinical setting, firstly to determine if topical infusions of HDL can improve wound repair and healing in diabetic patients with non-healing wounds or ulcers.

“We will also delve into the mechanisms underlying these effects further to identify future therapeutic targets,” he says.

The paper, entitled High Density Lipoproteins Rescue Diabetes-Impaired Angiogenesis via Scavenger Receptor Class B Type I, is published in the journal Diabetes.


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