IGF-axis activity and diabetic eye disease

Bioactive insulin-like growth factor (IGF) may be a biomarker for diabetic retinopathy (DR), said Troels Brynskov MD at the 16th EURETINA Congress. Dr Brynskov and colleagues at Zealand University Hospital, Roskilde, Denmark, investigated an association between the IGF-axis and DR in a cohort of obese patients with type 2 diabetes mellitus who were undergoing gastric bypass surgery. Their motivation for the study was based on existing evidence implicating the IGF-axis in the development of DR and their personal observations that DR worsened in patients who underwent gastric bypass surgery. The study included 18 patients with DR and 18 patients without DR. Comparisons between the two groups showed they were similar in almost all of their baseline and clinical characteristics, including duration of diabetes, HbA1c level, and blood pressure. However, the patients with DR had a significantly higher level of bioactive IGF than the group without DR (0.84ng/mL vs 1.27ng/ml; P=.03). During 12 months of follow-up after gastric bypass surgery, DR worsened in only three patients, thus limiting the ability to assess associations between IGF-axis changes and DR in a longitudinal manner, Dr Brynskov said. Two of the three patients with DR worsening developed increased IGF-1 levels, however, whereas the mean IGF-1 level was unchanged during follow-up in patients without DR worsening. The pattern of changes in other IGF-axis measurements were similar in the patients with and without DR worsening.