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Diabetic retinopathy is a serious complication of diabetes. Often diagnosed late, the disease has usually irreversible effects.

 

Diabetic retinopathy, a serious complication of diabetes

Diabetic retinopathy is a highly incapacitating microvascular complication of diabetes that is the leading cause of blindness in the active population.1

According to the French Diabetics Federation, close to 50% of type 2 diabetics are affected by the disease.2 Diabetic retinopathy affects the eye and the retina. The condition is caused by damage to the small blood vessels - the capillaries - in the eyes. Eyes are small organs irrigated by numerous blood vessels and the walls of these capillaries are weakened by frequent hyperglycemic episodes. Over time, this causes the vessels to start leaking and eventually rupture. The retina is no longer adequately oxygenated and produces new, weaker vessels. The damage progresses to the macula located in the center of the retina, causing reduced vision. Generally, this vision loss is only partially reversible.

Fortunately, in recent years, the prevalence of diabetic retinopathy has been tending to decrease thanks to the implementation of preventive initiatives and, in particular, screening.3

As is the case for many diabetes complications, if the problem is diagnosed late, the chances of maintaining good vision are reduced. Diabetic retinopathy is therefore a real challenge for scientific research.

 

Hopes of finding a treatment for diabetic retinopathy

Early diagnosis of diabetic retinopathy is the best tool to prevent vision loss and reduce the related costs. However, the disease is often silent and asymptomatic for several years. Currently, the most effective treatment for severe non-proliferative and proliferative diabetic retinopathy is photocoagulation with an argon laser and intravitreal injections of anti-VEGF. But unfortunately, sometimes these treatments have side effects and they can be associated with significant financial costs. They delay vision loss for a time by preventing abnormal retinal vessels from forming, but they are incapable of restoring full vision.

A team of Spanish researchers has published a review analyzing effects of oxidative stress and inflammation on vascular changes and the development of diabetic retinopathy.4

The scientists note that current therapies focus on already advanced stages of the disease. They observe that in diabetic retinopathy, retinal lesions and the neovascularization process are closely linked to the oxidative environment caused by chronic high blood sugar levels. Several in vitro and in vivo studies have demonstrated an efficacy of polyphenols to halt the progression of diabetic retinopathy. One of these studies, published in 2019, reports 400 natural products containing polyphenols acting on diabetes-related ophthalmological complications.5

So polyphenols may be able to combat oxidative stress, inflammation and the production of VEGF. Polyphenols are found in certain foods but the amounts are far too small to have an adequate effect. Scientific research is making progress and the use of polyphenols as a potential treatment appears to be an interesting new avenue to be explored.

Sources

  1. Guariguata L, Whiting D, Weil C, Unwin N. The International Diabetes Federation diabetes atlas methodology for estimating global and national prevalence of diabetes in adults. Diabetes Res Clin Pract. 2011 Dec;94(3):322-32. doi: 10.1016/j.diabres.2011.10.040. Epub 2011 Nov 17. PMID: 22100977.

  2. https://www.federationdesdiabetiques.org/information/complications-diabete/retinopathie#:~:text=La%20r%C3%A9tinopathie%20diab%C3%A9tique%20(atteinte%20des,de%20c%C3%A9cit%C3%A9%20avant%2065%20ans.

  3. Hammes HP. Optimal treatment of diabetic retinopathy. Ther Adv Endocrinol Metab. 2013 Apr;4(2):61-71. doi: 10.1177/2042018813477886. PMID: 23626903; PMCID: PMC3632004.

  4. Rodríguez ML, Pérez S, Mena-Mollá S, Desco MC, Ortega ÁL. Oxidative Stress and Microvascular Alterations in Diabetic Retinopathy: Future Therapies. Oxid Med Cell Longev. 2019 Nov 11;2019:4940825. doi: 10.1155/2019/4940825. PMID: 31814880; PMCID: PMC6878793.

  5. A. P. Laddha and Y. A. Kulkarni, “Tannins and vascular complications of diabetes: an update,” Phytomedicine, vol. 56, pp. 229–245, 2019.