Bioelectrical function and structural assessment of the retina in patients with early stages of Parkinson’s disease (PD)

Nowacka, Barbara; Lubiński, Wojciech; Honczarenko, Krystyna; Potemkowski, Andrzej; Safranow, Krzysztof

doi:10.1007/s10633-015-9503-0

Cited by 53 publications

(60 citation statements)

References 44 publications

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“…96,97 Reduced amplitudes of the ERG a-and bwaves, 98-101 the scotopic oscillatory potentials OP2 and OP3, and the overall index (OP1 + OP2 + OP3) were seen in PD patients, with prolonged mean peak times in OP1, OP2, OP3, and OP4. 21,99 In addition, the amplitude and latency of the pattern ERG P50 compound were reduced and delayed; 33,61,87,98,[102][103][104][105] and increased VEP latency (P100 and N70) has been reported in subsets of PD patients. 56,71,100,103,[106][107][108][109] Several lines of evidence support that ERG and VEP abnormalities are closely related to impaired dopaminergic transmission.…”

Section: Electrophysiologymentioning

confidence: 98%

“…On a cellular level, ERG abnormalities can be related to dopamine‐related mechanisms. Scotopic a‐wave abnormalities might reflect a distorted coupling between rods and cones, resulting in a dysfunctional shift from night‐ to daytime vision . Oscillatory potentials, on the other hand, are believed to be a read‐out for ON interactions of retinal interneurons and can thus be linked to the dopaminergic A18 amacrine cells that are known to be involved in ON pathways .…”

Section: Abnormalities In Oculo‐visual Functionsmentioning

confidence: 99%

“…Scotopic a-wave abnormalities might reflect a distorted coupling between rods and cones, resulting in a dysfunctional shift from night-to daytime vision. 99,[115][116][117] Oscillatory potentials, on the other hand, are believed to be a read-out for ON interactions of retinal interneurons and can thus be linked to the dopaminergic A18 amacrine cells that are known to be involved in ON pathways. 99,[118][119][120][121] Also, the photopic b-wave amplitude appears to be modulated by amacrine cells, and abnormalities could correspond to impaired light adaptation-a process modulated by dopamine.…”

Section: Electrophysiologymentioning

confidence: 99%

“…99,[115][116][117] Oscillatory potentials, on the other hand, are believed to be a read-out for ON interactions of retinal interneurons and can thus be linked to the dopaminergic A18 amacrine cells that are known to be involved in ON pathways. 99,[118][119][120][121] Also, the photopic b-wave amplitude appears to be modulated by amacrine cells, and abnormalities could correspond to impaired light adaptation-a process modulated by dopamine. 99,[121][122][123] Finally, abnormal-pattern ERG responses might be the result of impaired dopamine signaling via D1 and D2 dopamine receptors, affecting the center-surround receptive fields of RGCs.…”

Section: Electrophysiologymentioning

confidence: 99%

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Oculo‐visual abnormalities in Parkinson's disease: Possible value as biomarkers

et al. 2018

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Parkinson's disease (PD) is one of the most common neurodegenerative disorders and the second leading cause of dementia worldwide. With an aging population, the prevalence of the disease has dramatically increased. Clinical management has advanced through recent developments in dopaminergic imaging and genetic risk profiling. However, early and accurate diagnosis of the disorder remains a challenge, largely because of the lack of noninvasive and inexpensive reliable diagnostic tests. Besides the well‐studied cerebral neurodegeneration that underlies the cardinal symptoms of PD (ie, bradykinesia, tremor, rigidity, and postural instability), ocular changes have also been described in PD, including visual dysfunction, pupil abnormality, lens opacity, and retinal neuronal loss and dysfunction. These ocular pathological processes are related to α‐synuclein deposition, and dopamine deficiency in the retina—mirroring the defining pathological features of PD in the brain. Together, these observations support the notion that the eye can serve as a window to the brain, providing clinicians with noninvasive methods to visualize disease. This review focuses on recent advances in the characterization of ocular changes in PD and their promising use as biomarkers in the eye, which can be potentially used for aiding in early diagnosis, tracking disease progression, and valuating novel therapeutic strategies. © 2018 International Parkinson and Movement Disorder Society

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Section: Electrophysiologymentioning

confidence: 98%

Section: Abnormalities In Oculo‐visual Functionsmentioning

confidence: 99%

Section: Electrophysiologymentioning

confidence: 99%

Section: Electrophysiologymentioning

confidence: 99%

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Oculo‐visual abnormalities in Parkinson's disease: Possible value as biomarkers

et al. 2018

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“…For instance, at the clinical stage patients develop hallucinations, impaired eye and eyelid movement, and reduced amount and altered composition of tear fluid [3-5]. In addition, the dry eye symptom, blepharitis (bilateral recurrent inflammation of the part of the eyelid where the eyelashes grow), changes in eye accommodation (pupillary response to light), impaired secretion and outflow of intraocular fluid, reduced visual acuity, scotoma formation (areas in the field of vision where vision is either completely degenerated or partially diminished), and thinning of the retina layers, in particular, due to the reduction in the number of nerve fibers, are often observed in PD patients [5-7]. …”

Section: Introductionmentioning

confidence: 99%

Biochemical and Functional Changes in the Eye As a Manifestation of Systemic Degeneration of the Nervous System in Parkinsonism

Kim¹,

Павленко²,

Катаргина³

et al. 2018

Acta Naturae

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Parkinson’s disease (PD) is a systemic neurodegenerative condition caused by the death of dopaminergic neurons of the nigrostriatal system of the brain. This disease is diagnosed after most neurons have already been lost, which explains the low efficiency of treatment. Hope for increasing treatment efficiency rests in the development of new strategies for early diagnosis of PD based on a search for peripheral markers that appear as early changes in non-motor functions. Since impairment of the visual function is one of the manifestations of PD, the purpose of our work was to identify biochemical and physiological changes in a mouse’s eye and eyelid in models of preclinical (presymptomatic) and clinical (symptomatic) stages of PD. We found that the norepinephrine, dopamine, and serotonin levels in the mouse eye reduced not only in the model of the early clinical stage, but also in the model of preclinical stage, an indication that pathological changes in the monoaminergic systems of the brain had affected the eye even before the motor disorders emerged. Moreover, in both models of PD, mice had increased intraocular pressure, indicating the development of both metabolic and functional impairments, which can be used as diagnostic markers. Unlike in the eye, the serotonin level in the eyelid was increased in mice at both parkinsonism stages and in presymptomatic mice to a much higher extent than in symptomatic ones. Given that serotonin is involved in the regulation of lacrimal glands of the eyelid, an increase in its level in parkinsonian mice should alter the composition of tear fluid, which could serve as a diagnostic marker of early stage of PD. Thus, the changes in the metabolism of monoamines in the eye and eyelid observed in mice at the early stage of parkinsonism are accompanied by changes in the function of these structures and, therefore, can be used as diagnostic markers of the early stage of PD.

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Dopaminergic Retinal Cell Loss and Visual Dysfunction in Parkinson Disease

Ortuño‐Lizarán

Sánchez‐Sáez

Lax

et al. 2020

Annals of Neurology

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Objective: Considering the demonstrated implication of the retina in Parkinson disease (PD) pathology and the importance of dopaminergic cells in this tissue, we aimed to analyze the state of the dopaminergic amacrine cells and some of their main postsynaptic neurons in the retina of PD. Methods: Using immunohistochemistry and confocal microscopy, we evaluated morphology, number, and synaptic connections of dopaminergic cells and their postsynaptic cells, AII amacrine and melanopsin-containing retinal ganglion cells, in control and PD eyes from human donors. Results: In PD, dopaminergic amacrine cell number was reduced between 58% and 26% in different retinal regions, involving a decline in the number of synaptic contacts with AII amacrine cells (by 60%) and melanopsin cells (by 35%). Despite losing their main synaptic input, AII cells were not reduced in number, but they showed cellular alterations compromising their adequate function: (1) a loss of mitochondria inside their lobular appendages, which may indicate an energetic failure; and (2) a loss of connexin 36, suggesting alterations in the AII coupling and in visual signal transmission from the rod pathway. Interpretation: The dopaminergic system impairment and the affection of the rod pathway through the AII cells may explain and be partially responsible for the reduced contrast sensitivity or electroretinographic response described in PD. Also, dopamine reduction and the loss of synaptic contacts with melanopsin cells may contribute to the melanopsin retinal ganglion cell loss previously described and to the disturbances in circadian rhythm and sleep reported in PD patients. These data support the idea that the retina reproduces brain neurodegeneration and is highly involved in PD pathology.

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Bioelectrical function and structural assessment of the retina in patients with early stages of Parkinson’s disease (PD)

Cited by 53 publications

References 44 publications

Oculo‐visual abnormalities in Parkinson's disease: Possible value as biomarkers

Oculo‐visual abnormalities in Parkinson's disease: Possible value as biomarkers

Biochemical and Functional Changes in the Eye As a Manifestation of Systemic Degeneration of the Nervous System in Parkinsonism

Dopaminergic Retinal Cell Loss and Visual Dysfunction in Parkinson Disease

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