This new discovery is expected to open a new field of therapy for glaucoma and neurodegenerative diseases.
According to Dr Muneeb Faiq and Dr Tanuj Dada, scientists behind this study, this diabetes is uniquely different from the one accompanied with high blood glucose levels because it afflicts the brain and ocular tissues specifically.
Dr Faiq is a clinical researcher working on glaucoma, neurodegeneration and diabetes and Dr Dada is professor of ophthalmology at AIIMS, New Delhi.
Diabetes Type 1 and 2 are accompanied with high levels of glucose in the blood but according to the scientists, Diabetes Type 3 (Alzheimer’s disease) and Diabetes Type 4 (glaucoma) are restricted to the brain and ocular tissues respectively.
Dr Faiq and Dr Dada have also made a case for Parkinson’s disease to be referred as Diabetes Type 5.
Glaucoma is the leading cause of irreversible blindness with more than 65 million sufferers worldwide. It is accompanied with severe compromise in the quality of life, stress, depression, higher propensity to accidents and cognitive deficit in addition to huge economic burden. There is no cure for this malady and the only treatment currently available is lowering of eye pressure with medicines and/or surgery. The disease continues to progress even after controlling the pressure inside the eyes. That is why this disorder is also called “Sneak thief of sight”.
With a view of developing an effective remedy for glaucoma, scientists are busy in cutting edge research to know the nature and pathogenesis of this disorder. But, as of now, no effective theory to cover all the aspects of this disease has been found.
The research carried out by Dr Faiq and Dr Dada is likely to satisfy this long sought goal, which may ultimately help in developing an effective cure. Their findings have opened new doors towards understanding glaucomatous vision loss and immediately suggest measures for prevention and effective treatment.
According to the paper published in Current Molecular Medicine, diabetes can afflict the brain and can exist independent of the other already known types of diabetes. This brain diabetes may or may not be accompanied with high blood sugar. Brain is a separate compartment and much of its metabolism is independent of systemic metabolism.
Based on this idea, the researchers claim that brain can suffer from diabetes (independent of regular type 1 and type 2 forms). If the diabetes affects the cerebral part it becomes Alzheimer’s disease (Diabetes Type 3) and if it afflicts the visual pathway it becomes glaucoma (Diabetes Type 4).
The investigators argue that the whole concept is based on insulin signalling and what they have termed “Insulin Hypofunctionality”. Proper insulin signalling is important for the survival of neurons, particularly Retinal Ganglion Cells (cells that die in glaucoma). Loss of healthy insulin signalling causes “Insulin Hypofunctionality” which leads to the activation of many disease pathways that finally culminate in irreversible vision loss.
The discovery of glaucoma being Diabetes Type 4 is likely to make a paradigm shift in the understanding of this disorder and identifies brain as the potential diagnostic and therapeutic target in glaucoma. In the light of this discovery, insulin therapy (restoration of insulin signalling) is a promising therapeutic intervention in glaucoma as well as in Alzheimer’s disease and possibly Parkinson’s disease.