Cited by 466Neuroinflammation and Neurodegeneration MechanismsGlaucoma and retinal disordersRetinal Diseases and Treatments

The DOI matches its Crossref record; 297 of the 297 references it cites were found in a registry or an index; none of the 212 sources its claims cite is checked for support yet.

The role of microglia in retinal neurodegeneration: Alzheimer’s disease, parkinson, and glaucoma.

Open access
Ramirez, Ana I., de Hoz, Rosa, Salobrar-Garcia, Elena, Salazar, Juan J., Rojas, Blanca, Ajoy, Daniel, López-Cuenca, Inés, Rojas, Pilar, Triviño, Alberto, Ramírez, José M.·2017·Frontiers in Aging Neuroscience

Abstract

Microglia, the immunocompetent cells of the central nervous system (CNS), act as neuropathology sensors and are neuroprotective under physiological conditions. Microglia react to injury and degeneration with immune-phenotypic and morphological changes, proliferation, migration, and inflammatory cytokine production. An uncontrolled microglial response secondary to sustained CNS damage can put neuronal survival at risk due to excessive inflammation. A neuroinflammatory response is considered among the etiological factors of the major aged-related neurodegenerative diseases of the CNS, and microglial cells are key players in these neurodegenerative lesions. The retina is an extension of the brain and therefore the inflammatory response in the brain can occur in the retina. The brain and retina are affected in several neurodegenerative diseases, including Alzheimer's disease (AD), Parkinson's disease (PD), and glaucoma. AD is an age-related neurodegeneration of the CNS characterized by neuronal and synaptic loss in the cerebral cortex, resulting in cognitive deficit and dementia. The extracellular deposits of beta-amyloid (Aβ) and intraneuronal accumulations of hyperphosphorylated tau protein (pTau) are the hallmarks of this disease. These deposits are also found in the retina and optic nerve. PD is a neurodegenerative locomotor disorder with the progressive loss of dopaminergic neurons in the substantia nigra. This is accompanied by Lewy body inclusion composed of α-synuclein (α-syn) aggregates. PD also involves retinal dopaminergic cell degeneration. Glaucoma is a multifactorial neurodegenerative disease of the optic nerve, characterized by retinal ganglion cell loss. In this pathology, deposition of Aβ, synuclein, and pTau has also been detected in retina. These neurodegenerative diseases share a common pathogenic mechanism, the neuroinflammation, in which microglia play an important role. Microglial activation has been reported in AD, PD, and glaucoma in relation to protein aggregates and degenerated neurons. The activated microglia can release pro-inflammatory cytokines which can aggravate and propagate neuroinflammation, thereby degenerating neurons and impairing brain as well as retinal function. The aim of the present review is to describe the contribution in retina to microglial-mediated neuroinflammation in AD, PD, and glaucomatous neurodegeneration.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This review argues that microglial-mediated neuroinflammation is a shared pathogenic mechanism in Alzheimer’s disease, Parkinson’s disease, and glaucoma, and that retinal microglial changes may mirror brain pathology. It proposes that modulating microglial phenotype, rather than simply blocking activation, could be a therapeutic strategy and that retinal imaging may aid early diagnosis and monitoring.

Key findings

  • AD, PD, and glaucoma share chronic, age-related neurodegeneration with protein aggregates, glial activation, and neuroinflammation; microglial activation has been reported in all three, including in retina.
  • Microglia can adopt neurotoxic M1-like or neuroprotective M2-like phenotypes; the review concludes that shifting M1 toward M2 may be more effective than completely blocking microglial activation.
  • In AD models, retinal Aβ plaques appeared in APPswe/PS1ΔE9 mice as early as 2.5 months, preceding brain detection; in PD patients, macular inner retinal layer thinning of 15–20% has been reported.
  • In glaucoma, microglial activation is described as one of the first events, preceding RGC loss; minocycline or high-dose irradiation reduced microglial activation and RGC death in experimental models.

Methods

  • Narrative review of literature on microglia and retinal neurodegeneration in AD, PD, and glaucoma.
  • Synthesizes human postmortem/clinical findings and animal models, including transgenic AD mice, MPTP/rotenone PD models, and experimental/DBA/2J glaucoma models.
  • Includes a summary table (Table 1) of retinal changes and a schematic figure (Figure 1) of hypothetical neuroinflammatory events; no systematic search or meta-analysis is described.

Limitations

  • The paper states that the role of microglia in glaucoma pathophysiology is poorly understood and that better knowledge is needed.
  • The paper notes contradictory evidence: Williams et al. found no evidence of Tau, Aβ, TDP-43, ubiquitin, or α-syn deposits in any part of the eyeball in AD patients.
  • Evident from the text: this is a narrative review without stated systematic search, quality appraisal, or primary data, and it relies heavily on animal models and postmortem human tissue.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.3389/fnagi.2017.00214

Cites

297 of 297 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Figures

Figure 1 Schematic representation of the hypothetical events associated with the neuroinflammation in AD (A), PD (B), and glaucoma (C). AD, Alzheimer's Disease; PD, Parkinson's Disease; ILM, inner limitant membrane; NFL, nerve fiber layer; GCL, ganglion cell layer; IPL, inner plexiform layer; INL, inner nuclear layer; OPL, outer plexiform layer; ONL, outer nuclear layer; OLM, outer limitant membrane; PL, photoreceptor layer; RPE, retinal pigment epithelium; BM, Bruch membrane; C, choroid; Aβ, beta-amyloid; pTau, phosphorylated tau.
Figure 1 Schematic representation of the hypothetical events associated with the neuroinflammation in AD (A), PD (B), and glaucoma (C). AD, Alzheimer's Disease; PD, Parkinson's Disease; ILM, inner limitant membrane; NFL, nerve fiber layer; GCL, ganglion cell layer; IPL, inner plexiform layer; INL, inner nuclear layer; OPL, outer plexiform layer; ONL, outer nuclear layer; OLM, outer limitant membrane; PL, photoreceptor layer; RPE, retinal pigment epithelium; BM, Bruch membrane; C, choroid; Aβ, beta-amyloid; pTau, phosphorylated tau.CC BY · PubMed Central

Verification

Claims the paper makes

155 Not checked yet · 39 No basis given · 21 Own interpretation · 1 Sources not found

Verify all 210 references — free account

Show all 93 claims

  • Probably not a substantial claim. 48
  • It may state two separate claims as one. 94
123 of 123
  • The paper relies on this without support.

    LRRK2 is the most commonly mutated gene in both idiopathic and familial PD.

    “LRRK2 is the most commonly mutated gene in both idiopathic and familial PD.”
  • The paper relies on this without support.

    Persistent microglial activation exerts harmful effects that result in dopaminergic neuron death.

    “Persistent microglial activation is known to exert harmful effects that result in dopaminergic neuron death.”
  • The paper relies on this without support.

    Dopaminergic neurons are especially sensitive to factors that can induce cell damage and eventually cell death.

    “In addition, dopaminergic neurons seem to be especially sensitive to several factors that can induce cell damage and eventually cell death.”
  • The paper relies on this without support.

    Astrocytes secrete glutathione and transport it to neurons in response to neural excitatory stimuli.

    “Astrocytes are responsible for secreting glutathione and transporting to neurons in response to neural excitatory stimuli.”
  • The paper relies on this without support.

    α-syn aggregates are related to neurodegenerative disorders, including PD.

    “However, α-syn aggregates are related to neurodegenerative disorders, including PD.”
  • The paper relies on this without support.

    Under physiological conditions, some microglial cells express very low levels of MHC-II, although pro-inflammatory cytokines can upregulate MHC-II expression by microglial cells.

    “Under physiological conditions, some microglial cells express very low levels of MHC-II, although certain pro-inflammatory cytokines (e.g., TNF-α or IFN-γ) can upregulate MHC-II expression by microglial cells.”
  • The paper relies on this without support.

    For retinal homeostasis, the level of complement proteins should be low.

    “For retinal homeostasis, the level of complement proteins should be low.”
  • The paper relies on this without support.

    The retina is a projection of the CNS.

    “because the retina is a projection of the CNS.”
8 of 8

Claims other papers make about this one

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Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

1 of 1

Citations

Cites

1 retracted

Research works printed but not linked: 5

  1. Garcia-Ospina, 2003, Neuronal DNA damage correlates with a positive detection of c-Jun, nuclear factor kB, p53 and Par-4 transcription factors in Alzheimer's disease, Rev. Neurol, 36, 1004
  2. Guimaraes, 2009, Mechanisms of secondary degeneration in the central nervous system during acute neural disorders and white matter damage, Rev. Neurol., 48, 304
  3. Martínez-Lazcano, 2010, Radicales libres y estrés oxidativo en las enfermedades neurodegenerativas, Mensaje Bioquim, 34, 43
  4. Park, 2013, Neurodegeneration in Glaucoma and Alzheimer's disease, 59
  5. Salobrar-García, cular manifestations of dementia: the eye and its role in the diagnosis and monitoring, Chapter 15

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Metadata

Authors
Ramirez, A. I., de Hoz, R., Salobrar-Garcia, E., Salazar, J. J., Rojas, B., Ajoy, D., López-Cuenca, I., Rojas, P., Triviño, A., & Ramírez, J. M.
Affiliations
Universidad Complutense de Madrid (ES)
Venue
Frontiers in Aging Neuroscience
Published
2017-07-06
Volume
9
Pages
214-214
ISSN
1663-4365 (ISSN-L)
OpenAlex
W2728593064
Cited by
466
References
297
Citations by year
2026: 25 · 2025: 41 · 2024: 50 · 2023: 51 · 2022: 66 · 2021: 78 · 2020: 59 · 2019: 47 · 2018: 38 · 2017: 11
FWCI
4.09
Type
journal article
Language
en
Open access
Licence
cc-by
Locations
  • Frontiers in Aging Neuroscience (publishedVersion, cc-by)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • Library Open Repository (Universidad Complutense Madrid) (submittedVersion)
  • LA Referencia (Red Federada de Repositorios Institucionales de Publicaciones Científicas) (submittedVersion, other-oa)
  • DOAJ (DOAJ: Directory of Open Access Journals) (submittedVersion, cc-by-sa)
Funders
  • Instituto de Salud Carlos III (RD16/0008/0005)
  • Ministerio de Economía y Competitividad (SAF-2014-53779-R)
  • Ministerio de Educación, Cultura y Deporte (FPU13/01910)
Topics
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
  • Health Sciences › Medicine › Ophthalmology › Glaucoma and retinal disorders
  • Health Sciences › Medicine › Ophthalmology › Retinal Diseases and Treatments
Keywords
microglia, retinal neurodegeneration, neuroinflammation, Alzheimer's disease, Parkinson's disease, glaucoma, amyloid-beta, tau protein, alpha-synuclein, Lewy bodies, retinal ganglion cell death, dopaminergic neurons, optic nerve, inflammatory cytokines, microglial activation

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