Levels of Anti-Insulin Antibodies in Patients with Diabetic Retinopathy Attending National Diabetes Research and Management Centre in Accra

Abstract

Background: Diabetes mellitus (DM) is one of the most common chronic diseases worldwide, and has attained epidemic status the past few decades especially in middle and low income countries. Diabetic retinopathy (DR) has become the most common microvascular complication of diabetes, and remains a leading cause of visual impairment and blindness in the working-age population in the developing world. Anti-insulin antibodies are glycoprotein molecules produced by the immune system and play a significant role in the body‘s defense against pathogens. These immuno-globulins, especially IgE, may be responsible for allergies by increasing the porosity of the blood retinal barrier causing leakage, pericyte and endoththelial cell loss and retinal neovascularization. Immunoglobulin G (IgG) may also be responsible for insulin resistance by upregulation of inflammatory molecule expressions, promoting leakostasis and increasing vascular permeability in retina. Aim: The aim of the study was to evaluate the relationship between anti-insulin antibodies and subjects with diabetic retinopathy. Methodology: This was a case-control study involving 90 individuals – forty (40) diagnosed with diabetic retinopathy and twenty-five (25) each of individuals with diabetes mellitus and apparently healthy non-diabetics serving as controls recruited at the National Diabetic Research Centre and the eye unit of the Korle-bu Teaching Hospital (KBTH). These individuals were interviewed using a standard questionnaire. Five milliliters (5mls) of venous blood was taken from participants, following standard procedures, and transported to the Department of Chemical Pathology Research Laboratory for biochemical analysis. With the aid of the Statistical Products and Services Solutions (SPSS), version 25 software, the data obtained were summarized using descriptive statistics (means, standard deviations, and proportions) and further analyzed at a 0.05 alpha level using one-way between-groups analysis of variance (ANOVA). Associations between variables were determined using Pearson‘s product-moment correlations. Results: In general, with the exception of the control group, which had a higher proportion of its participants being males (60%, n = 15), most of the participants were females in both the retinopathy (65%, n = 26) and diabetes (76%, n = 19) groups. Higher levels of IgE and IgG concentrations were observed to be higher in diabetic retinopathy subjects than those of the diabetic without retinopathy group (p< 0.05). Furthermore, the factors that had significant associations with anti-insulin IgE and IgG antibodies were: fasting blood glucose, occupation, age, gender, and being on medications (p< 0.05 respectively). Being on nifedipine medication (r = -0.32, p = 0.04) had a significant negative correlation with the levels of anti-insulin IgE antibodies, whiles being on metformin medication (r = 0.32, p = 0.04) had a significant positive relationship with the levels of anti-insulin IgG antibodies. Conclusion: Among the study participants sampled, neither diabetes nor diabetic retinopathy influenced the levels of anti-insulin IgE and IgG antibodies. Furthermore, the factors that had significant associations with anti-insulin IgE and IgG antibodies were: fasting blood glucose, occupation, age, gender, and being on tropicamide, methyldopa, and Phenylephrine medications.