An asthma drug could prevent changes caused in the early stages of diabetic retinopathy, US scientists report.
Montelukast (marketed as Singulair) was shown to inhibit the impact of diabetic retinopathy in mice with type 1 diabetes, with clinical trials now planned to test the findings in humans.
Diabetic retinopathy is caused by high blood glucose levels damaging the back of the eye. This can be prevented to some degree by maintaining normal blood glucose through eating a healthy diet.
The drugs available to treat retinopathy are mostly geared towards treating the later stages of the condition, but these findings indicate early symptoms could be treated too.
Asthma drugs, which help to reduce inflammation, have previously been associated with benefits for blood glucose control and insulin sensitivity in people with type 2 diabetes.
In this new study the anti-inflammatory effects of montelukast were tested by researchers from University Hospitals Rainbow Babies and Children’s Hospital and Case Western Reserve University School of Medicine to see if it impacted the inflammation that develops in diabetic retinopathy.
In diabetic mice models, the dose of the drug led to suppression of chronic inflammation, improving the symptoms associated with early signs of retinopathy damage.
“We found that montelukast was able to disrupt the signalling of inflammatory molecules called leukotrienes,” said lead author Dr Rose Gubitosi-Klug. “This disruption significantly reduced small blood vessel and nerve damage that we see in the early stages of diabetic retinopathy.”
As the drug is already approved both in the UK and the US for use in children and adolescents, the “re-purposing” of the medication could help to speed up the time needed to get approval to test the effect of the drug in humans.
Dr Gubitosi-Klug added: “The daily dose equivalent used in the current study is similar to the once daily dose used in the treatment of asthma. Reassuringly, in our diabetes model as in asthma studies, this dose allows effective suppression of chronic inflammation, which can prevent pathology, but avoids complete inhibition of inflammation, which can compromise innate immunity.
“Moreover, montelukast was efficacious in both prevention and delayed intervention approaches, which implies relevance to patients with newly-diagnosed diabetes as well as individuals living with diabetes of longer duration. Thus, there is promise that a safe treatment that effectively stabilises airways in asthma may also preserve small blood vessels and nerve cells in diabetes.”
The research was published online in the journal