Marker in tears detect diabetes complication
We have heard of blood tests & stool samples. Tear samples might be the next-screening method to enter your doctor’s office, a new research study from UNSW, Sydney, suggests.
Tear testing may be the future of screening for diabetic peripheral neuropathy which is a debilitating condition that affects people with diabetes, a new study from UNSW Sydney suggests.
This study, recently published in The Ocular Surface, is the first to show that peripheral nerve damage which is often the earliest sign of the condition, can be traced in the tear film.
Dr. Maria Markoulli who is the senior author of the research, said they have found that the people with type 1 diabetic peripheral neuropathy which can result in recurring ulcers of the feet and in severe cases require amputation, have reduced levels of a protein known as ‘substance P’ in their tear film.
She added that 119,000 Australians have type 1 diabetes. And in the future, they may be able to have a quick tear sample collected either at their optometrist or the chemist, GP or endocrinologist & be told whether they are at risk.
Peripheral neuropathy is one of the most common complications of diabetes & affects almost 50% of diabetics. This occurs when chronically high blood sugar damages the nerves that connect the brain & spinal cord to the rest of the body parts.
The symptoms include pain, numbness, weakness, pins, imbalance, and needles, & recurring foot ulcers.
While the nerve damage cannot be reversed, early detection can help patients better manage this condition & also to prevent further complications. Current early testing options are limited to the invasive examinations, such as skin biopsies.
Dr. Markoulli said that peripheral neuropathy is notoriously difficult to detect early on & it requires special training. What the team proposing with this method is something that will be done quickly, non-invasively & potentially could be done even by a non-specialist.
The scientists tested the concentration of 2 proteins called neuropeptides, in the tear film of people with type 1 & type 2 diabetes compared to control groups. The research study consisted of almost 100 participants.
While the team found that those with type 1 diabetic peripheral neuropathy had less ‘substance P’ protein in their tear film, the results didn’t suggest that type 2 diabetes has the same biomarkers. This is because these diseases have different pathologies& risk factors, writes Ph.D. candidate & lead author of the research, Mr. Shyam Sunder Tummanapalli.
Dr. Markoulli added that it tells us that the 3 disease processes are quite different. Dr. Markoulli is eager to expand the study to determine specific changes in type 2 diabetes. What proteins change there? Is there also a link to the tear film and peripheral neuropathy?
While the study results are promising for those with type 1 diabetes, further study is required before tear testing becomes available clinically. In particular, the researchers hope to study ‘substance P’ loss over time according to varying severities of peripheral neuropathy.
Editor’s Note: Substance P in tears, Marker in tears detect diabetes complication, UNSW research, Noninvasive test, tear fluid biomarkers, a useful marker of diabetes-related nerve damage.