Early Microvascular and Oscillatory Potentials Changes in Human Diabetic Retina: Amacrine Cells and the Intraretinal Neurovascular Crosstalk

Abstract

To analyze the early microvascular retinal changes and oscillatory potentials alterations secondary to diabetic retinal damage, 44 eyes of 22 diabetic patients without and with mild diabetic retinopathy (DR) and 18 eyes of 9 healthy controls were examined. All subjects underwent spectral domain optical coherence tomography (SD-OCT), OCT angiography (OCTA), and electroretinography of oscillatory potentials (OPs). At OCTA, vessel area density (VAD), vessel length fraction (VLF), and fractal dimension (FD) were significantly reduced in the superficial vascular plexus (SVP), VLF and FD in the intermediate capillary plexus (ICP), and FD in the deep capillary plexus (DCP) in the diabetic group compared to the control group. The amplitude (A) of OP2, OP3, OP4 and the sum of OPs were significantly reduced in the diabetic group versus the controls, and the last two parameters were reduced also in patients without DR versus the controls. Moreover, in the diabetic group, a significant direct correlation was found between the A of OP1, OP2, OP3 and sOP and the VLF and FD in the SVP, while a statistically significant inverse correlation was found between the A of OP3 and OP4 and the VDI in the ICP and DCP. The reduced oscillatory potentials suggest a precocious involvement of amacrine cells in diabetic eyes, independently of DR presence, and their correlation with vascular parameters underlines the relevance of the crosstalk between these cells and vascular components in the pathophysiology of this chronic disease.

Efficacy and Safety of Subthreshold Micropulse Yellow Laser for Persistent Diabetic Macular Edema After Vitrectomy: A Pilot Study

“…Indeed, as already demonstrated by previous studies, it does not cause any chorioretinal foveal damage ( Midena et al, 2019 ; Elfalah et al, 2021 ; Fallico et al, 2021 ). In our study no modifications on autofluorescence or on FFA have been detected, supporting its safety even when used on the macular area ( Gawecki, 2019 ; Midena et al, 2021 ). These results confirm that SMYL therapy acts on the outer blood–retinal barrier and on the pigmented epithelium (RPE) ( Gawecki 2019 ; Frizziero et al, 2021 ; Midena et al, 2021 ).…”

“…In our study no modifications on autofluorescence or on FFA have been detected, supporting its safety even when used on the macular area ( Gawecki, 2019 ; Midena et al, 2021 ). These results confirm that SMYL therapy acts on the outer blood–retinal barrier and on the pigmented epithelium (RPE) ( Gawecki 2019 ; Frizziero et al, 2021 ; Midena et al, 2021 ). RPE layer is considered to be the main site of action of SMYL.…”

Spontaneous electroretinogram signals to screen people with early risk factors for diabetic retinopathy

“…1F ) were reduced in ERGs of spontaneously obese mice and streptozotocin-treated rat, respectively. In contrast, oscillatory potentials (OPs), considered as the most precociously altered ERG parameter in diabetes 34 , remain unchanged in high-fat diet-fed mice ( Supplementary Fig. 1D, 1E ).…”

Retinal Microvascular and Neuronal Changes Are Also Present, Even If Differently, in Adolescents with Type 1 Diabetes without Clinical Diabetic Retinopathy

“…As regards OCTA, the automatic segmentation algorithm (Heyex Software) identified the superficial vascular plexus (SVP) from RNFL to 17 μm above IPL (IPL-), the intermediate capillary plexus (ICP) from IPL- to 22 μm below IPL (IPL+), the deep capillary plexus (DCP) from IPL+ to OPL in the macular area, and RPCP in the optic disc area [ 27 ]. Quantitative analysis of the vascular plexuses in the OCTA en-face images was performed using the open-source, available ImageJ software (National Institutes of Health, Bethesda, MD, USA).…”

“…Three parameters were analyzed: vessel area density (VAD), vessel length fraction (VLF) and vessel diameter index (VDI). To obtain high-quality OCTA images, a signal strength (SS) of more than 30 in “Q score” (on a scale of 0 to 40 for Spectralis, Heidelberg, Germany) was required during OCTA acquisition [ 27 ].…”