Abstract
Purpose :
To investigate the relationship between macular ganglion cell layer–inner plexiform layer (GCL-IPL) thickness measured by optical coherence tomography (OCT) and systemic metabolic parameters in individuals with prediabetes, diabetes mellitus (DM) and normal subjects.
Methods :
Both eyes from 18 patients with prediabetes (HbA1c:5.7-6.4), 13 patients with DM (HbA1c>6.4), and 17 controls (HbA1c<5.7) were included in this prospective study. Retinal imaging was performed using the Heidelberg Spectralis instrument. GCL-IPL thickness was calculated in each of the Early Treatment of Diabetic Retinopathy Study (ETDRS) subfields, with manual correction of automated segmentation by a masked experienced observer when required. Serum samples were collected and quantitatively analyzed for leptin and adiponectin. Body mass index (BMI) was also calculated for each participant. Leptin, adiponectin, and BMI were compared among groups using ANOVA. To investigate their association with retinal thickness, linear mixed effects models with a random intercept to account for inter-eye correlation were used. p<0.05 was considered statistically significant.
Results :
There was no statistically significant difference in mean BMI, leptin, or adiponectin between groups. Overall, there was a negative association between leptin and GCL-IPL thickness in all inner subfields, with each unit increase in leptin associated with the following changes in GCL-IPL thickness: -0.25 µm (95% CI: -0.42, -0.07, p=0.004) in superior inner (SI), -0.21 µm (95% CI: -0.39, -0.04, p=0.014) in nasal inner (NI), -0.22 µm (95% CI: -0.41, -0.03, p=0.021) in inferior inner (II) and -0.20 µm (95% CI: -0.37, -0.02, p=0.029) in temporal inner (TI). Conversely, adiponectin showed a positive association with GCL-IPL thickness in the nasal outer (0.39 µm, 95% CI: 0.03, 0.76, p=0.034) and inferior outer (0.31 µm, 95% CI: 0.00, 0.62, p=0.047) subfields.
Conclusions :
Serum leptin levels have been associated with severity of retinopathy in DM. In addition, leptin and adiponectin are associated with adiposity, glycemia and neurodegeneration. In our study, leptin showed a significant association with decreased GCL-IPL thickness in individuals with or without diabetes, specifically in the inner ETDRS ring. These results suggest that increased leptin maybe linked with inner retinal neurodegeneration independent of glycemic status.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.