Signaling mediated by cytokines and chemokines is involved in glaucoma-associated neuroinflammation and in the damage of retinal ganglion cells (RGCs). Using multiplexed immunoassay and ...immunohistochemical techniques in a glaucoma mouse model at different time points after ocular hypertension (OHT), we analyzed (i) the expression of pro-inflammatory cytokines, anti-inflammatory cytokines, BDNF, VEGF, and fractalkine; and (ii) the number of Brn3a+ RGCs. In OHT eyes, there was an upregulation of (i) IFN-γ at days 3, 5, and 15; (ii) IL-4 at days 1, 3, 5, and 7 and IL-10 at days 3 and 5 (coinciding with downregulation of IL1-β at days 1, 5, and 7); (iii) IL-6 at days 1, 3, and 5; (iv) fractalkine and VEGF at day 1; and (v) BDNF at days 1, 3, 7, and 15. In contralateral eyes, there were (i) an upregulation of IL-1β at days 1 and 3 and a downregulation at day 7, coinciding with the downregulation of IL4 at days 3 and 5 and the upregulation at day 7; (ii) an upregulation of IL-6 at days 1, 5, and 7 and a downregulation at 15 days; (iii) an upregulation of IL-10 at days 3 and 7; and (iv) an upregulation of IL-17 at day 15. In OHT eyes, there was a reduction in the Brn3a+ RGCs number at days 3, 5, 7, and 15. OHT changes cytokine levels in both OHT and contralateral eyes at different time points after OHT induction, confirming the immune system involvement in glaucomatous neurodegeneration.
There is growing evidence that thinned retinal regions are interspersed with thickened regions in all retinal layers of patients with Alzheimer's disease (AD), causing roughness to appear on layer ...thickness maps. The hypothesis is that roughness of retinal layers, assessed by the fractal dimension (FD) of their thickness maps, is an early biomarker of AD. Ten retinal layers have been studied in macular volumes of optical coherence tomography from 24 healthy volunteers and 19 patients with mild AD (Mini-Mental State Examination 23.42 ± 3.11). Results show that FD of retinal layers is greater in the AD group, the differences being statistically significant (p < 0.05). Correlation of layer FD with cognitive score, visual acuity and age reach statistical significance at 7 layers. Nearly all (44 out of 45) FD correlations among layers are positive and half of them reached statistical significance (p < 0.05). Factor analysis unveiled two independent factors identified as the dysregulation of the choroidal vascular network and the retinal inflammatory process. Conclusions: surface roughness is a holistic feature of retinal layers that can be assessed by the FD of their thickness maps and it is an early biomarker of AD.
In the last 2 decades, endoscopic endonasal transsphenoidal surgery has become the most popular choice of neurosurgeons and otolaryngologists to treat lesions of the skull base, with minimal ...invasiveness, lower incidence of complications, and lower morbidity and mortality rates compared with traditional approaches. The transsphenoidal route is the surgical approach of choice for most sellar tumors because of the relationship of the sphenoid bone to the nasal cavity below and the pituitary gland above. More recently, extended approaches have expanded the indications for transsphenoidal surgery by using different corridors leading to specific target areas, from the crista galli to the spinomedullary junction. Computer-assisted surgery is an evolving technology that allows real-time anatomic navigation during endoscopic surgery by linking preoperative triplanar radiologic images and intraoperative endoscopic views, thus helping the surgeon avoid damage to vital structures. Preoperative computed tomography is the preferred modality to show bone landmarks and vascular structures. Radiologists play an important role in surgical planning by reporting extension of sphenoid pneumatization, recesses and septations of the sinus, and other relevant anatomic variants. Radiologists should understand the relationships of the sphenoid bone and skull base structures, anatomic variants, and image-guided neuronavigation techniques to prevent surgical complications and allow effective treatment of skull base lesions with the endoscopic endonasal transsphenoidal approach.
Microglial activation is associated with glaucoma. In the model of unilateral laser-induced ocular hypertension (OHT), the time point at which the inflammatory process peaks remains unknown. ...Different time points (1, 3, 5, 8, and 15 d) were compared to analyze signs of microglial activation both in OHT and contralateral eyes. In both eyes, microglial activation was detected in all retinal layers at all time points analyzed, including: i) increase in the cell number in the outer segment photoreceptor layer and plexiform layers (only in OHT eyes) from 3 d onward; ii) increase in soma size from 1 d onward; iii) retraction of the processes from 1 d in OHT eyes and 3 d in contralateral eyes; iv) increase in the area of the retina occupied by Iba-1+ cells in the nerve fiber layer/ganglion cell layer from 1 d onward; v) increase in the number of vertical processes from 1 d in contralateral eyes and 3 d in OHT eyes. In OHT eyes at 24 h and 15 d, most Iba-1+ cells were P2RY12+ and were down-regulated at 3 and 5 d. In both eyes, microglial activation was stronger at 3 and 5 d (inflammation peaked in this model). These time points could be useful to identify factors implicated in the inflammatory process.
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.
In Alzheimer's disease (AD), vascular changes could be caused by amyloid beta (Aβ) aggregates replacing the contractile smooth musculature of the arteriole walls. These changes happen in the brain ...vascular network, but also in the eye, and are related to decreased vascular density and low blood flow. In patients with Alzheimer's disease, thinning of the choroid and the retina has been shown. The aim of this prospective study was to assess the retinal and choroidal vascular systems, analyzing the choroidal thickness with optical coherence tomography (OCT), the foveal avascular zone (FAZ) with OCT-angiography (OCTA), and the optic nerve head (ONH) hemoglobin with the Laguna ONhE program, to evaluate which of the two ocular vascular systems shows earlier changes in mild AD patients. These patients, compared to controls, showed a significantly thinner choroid at all the analyzed points, with the exception of the temporal macula (at 1000 and 1500 µm from the fovea). On the other hand, the FAZ and ONH hemoglobin did not show significant differences. In conclusion, a thinner choroid was the main ocular vascular change observed in mild AD patients, while the retinal vessels were not yet affected. Therefore, choroidal thickness could be used an early biomarker in AD.
Alzheimer's Disease (AD) can cause degeneration in the retina and optic nerve either directly, as a result of amyloid beta deposits, or secondarily, as a result of the degradation of the visual ...cortex. These effects raise the possibility that tracking ophthalmologic changes in the retina can be used to assess neurodegeneration in AD. This study aimed to detect retinal changes and associated functional changes in three groups of patients consisting of AD patients with mild disease, AD patients with moderate disease and healthy controls by using non-invasive psychophysical ophthalmological tests and optical coherence tomography (OCT).
We included 39 patients with mild AD, 21 patients with moderate AD and 40 age-matched healthy controls. Both patients and controls were ophthalmologically healthy. Visual acuity, contrast sensitivity, colour perception, visual integration, and choroidal thicknesses were measured. In addition, OCT and OCT angiography (OCTA) were applied.
Visual acuity, contrast sensitivity, colour perception, and visual integration were significantly lower in AD patients than in healthy controls. Compared to healthy controls, macular thinning in the central region was significant in the mild AD patients, while macular thickening in the central region was found in the moderate AD group. The analysis of macular layers revealed significant thinning of the retinal nerve fibre layer, the ganglion cell layer and the outer plexiform layer in AD patients relative to controls. Conversely, significant thickening was observed in the outer nuclear layer of the patients. However, mild AD was associated with significant thinning of the subfovea and the nasal and inferior sectors of the choroid. Significant superonasal and inferotemporal peripapillary thinning was observed in patients with moderate disease.
The first changes in the mild AD patients appear in the psychophysical tests and in the central macula with a decrease in the central retinal thickness. When there was a disease progression to moderate AD, psychophysical tests remained stable with respect to the decrease in mild AD, but significant thinning in the peripapillary retina and thickening in the central retina appeared. The presence of AD is best indicated based on contrast sensitivity.
Purpose: The aim of this work was to analyse in subjects at high risk of developing Alzheimer's disease (AD) the possible correlation between psychophysical tests and magnetoencephalography (MEG) in ...comparison with control subjects.
Methods: Extensive ophthalmological analysis, MEG recording, genotyping and magnetic resonance imaging (MRI) were performed on 149 healthy subjects, of whom 109 had a family history of the disease and 40 did not. This sample was subdivided into subgroups aged 40–60 years with an increased risk of AD based on the presence of the ApoEɛ4 allele (ApoEɛ4+) and family history (FH+). 28 participants as higher risk group (ApoEɛ4+ and FH+) and 16 participants as lower risk group (FH‐ and ApoEɛ4‐).
Results: In the ApoEɛ4+ and FH+ group, a significant increase in visual acuity was observed, as well as an increase in some spatial frequencies of contrast sensitivity. In addition, in this group, some areas of the inner plexiform layer and the inner nuclear layer were thinned. Between the risk groups, when directly comparing M100 latency or temporal frequency activity associated with the visual response, no significant differences were found. However, there was an association between higher visual acuity and earlier M100 latency and increased activity in the high‐risk groups.
Conclusions: There seems to exist an early hyperactivation of the visual system, which would act as a compensatory mechanism, or be a manifestation of a biological malfunction that ultimately leads to toxicity. This hyperactivation represents the first evidence of the consequences of early retinal damage, associated with genetic risk, on visual processing. These changes observed by readily available and non‐invasive techniques could constitute a set of biomarkers for early detection of the disease and assessment of the efficacy of possible future treatments.
Purpose: To analyse the anti‐inflammatory effect of saffron extract, by regulating the expression of cytokines and chemokines involved in the neuroinflammatory process leading to retinal ganglion ...cell (RGC) damage, in a mouse model of unilateral laser‐induced ocular hypertension (OHT).
Methods: Three groups of Albino Swiss mice treated with saffron extract were used; saffron naïve group (SNG), saffron laser group 1 day (SLG1d) and saffron laser group 3 days (SLG3d). Both eyes with OHT (treated with laser photocoagulation) and their contralateral were analysed. Retinal samples were processed and multiarray kits (MILLIPLEX MAP Mouse Cytokine/Myokine Magnetic Bead Panel) were used to quantify the expression of: IL‐1β, IL‐4, IL‐6, IL‐10, IL‐17, IFN‐ϒ, TNF‐α, Brain‐derived Neurotrophic Factor (BDNF), Vascular Endothelial Growth Factor (VEGF) and Fractalkine. Immunohistochemical analysis was performed to locate cells expressing the factors and cytokines detected in the multiplex assay.
Results: After saffron treatment, no significant differences were found, at 1 and 3 days after laser‐induced OHT, between the concentration of proinflammatory cytokines (IL‐1β, IFN‐γ, TNF‐α and IL‐17), anti‐inflammatory cytokines (IL‐4 and IL‐10), BDNF, VEGF, and fractalkine in both the OHT eye and its contralateral eye, compared to saffron naïve. IL‐6 levels increased significantly in the OHT eye in SLG1d, reaching normal values at SLG3d compared to SNG. These results are contrary to those found in OHT eyes and their contralateral not treated with saffron, in which changes in cytokine levels were observed.
Conclusions: Saffron is effective in regulating the production of proinflammatory cytokines, VEGF, and fractalkine induced by increased IOP, thus protecting the retina from its related damage. Saffron could be beneficial as coadjutant therapies in the treatment of glaucoma, thus helping to decrease the inflammatory process that occurs in this pathology.
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