Abstract
Purpose :
Besides the motor deficits, Parkinson’s disease (PD) patients display visual disturbances in the early stages of the disease. One of these symptoms is the impairment of motion perception. Hence, we sought to evaluate if the main cell type involved in motion perception, the starburst amacrine cells, are degenerated in PD and if so, whether this degeneration is related to the degeneration of the dopaminergic system.
Methods :
Human eyes from control and PD donors were available for this study. Tyrosine hydroxylase-positive cell density (dopaminergic amacrine cells), choline acetyltransferase-positive cell density (starburst amacrine cell) was evaluated by immunohistochemistry and confocal microscopy in whole-mount retinas. We also quantified the dopaminergic synaptic contacts with starburst amacrine cells using vesicular monoamine transporter-2 (VMAT2) antibodies.
Results :
We found a significant decrease in the number of dopaminergic amacrine cells in PD retinas. Moreover, there is a decrease in the density of starburst amacrine cells in the two plexuses where they are located. Importantly, this work describes for the first time that dopaminergic amacrine cells contact with starburst amacrine cells in healthy control retinas and that these connections decrease in PD.
Conclusions :
This work shows that there is a degeneration of starburst amacrine cells and their synaptic connections with dopaminergic cells which may explain the motion perception alterations in PD. Hence, these alterations can be used as a biomarker of the pathology using functional tests for motion perception.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.