How many aqueous humor outflow pathways are there?

Costagliola, Ciro; dell’Omo, Roberto; Agnifili, Luca; Bartollino, Silvia; Fea, Antonio; Uva, Maurizio G.; Zeppa, Lucio; Mastropasqua, Leonardo

doi:10.1016/j.survophthal.2019.10.002

Cited by 53 publications

(53 citation statements)

References 236 publications

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“…All these parts work together to maintain the IOP within a physiological range [ 16 , 157 ], mainly due to cellular mechano-sensory systems, mechano-transduction mechanisms, cytoskeletal responses and finely-regulated signaling pathways, as well as the interactions with the extracellular matrix (ECM) [ 158 ].…”

Section: Trabecular Meshwork (Tm) and Location Of Outflow Resistanmentioning

confidence: 99%

“…TME act as a control on the SCE permeability by releasing vasoactive cytokines and other factors while the SCE form ‘‘giant vacuoles’’ only when the IOP exceeds the pressure in the episcleral venous plexus. Nevertheless, the outflow resistance seems to result mainly both from a synergistic interaction through the cell-to-cell junctions between the SCE in the inner wall, their basement membrane and/or the TEM [ 158 , 173 ]. The endothelial cells in the inner wall, in turn, undergo a basal-apical pressure gradient due to the biomechanical micro-environment.…”

Section: Trabecular Meshwork (Tm) and Location Of Outflow Resistanmentioning

confidence: 99%

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Neuroinflammation in Primary Open-Angle Glaucoma

Vernazza

Tirendi

Bassi

et al. 2020

JCM

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Primary open-angle glaucoma (POAG) is the second leading cause of irreversible blindness worldwide. Increasing evidence suggests oxidative damage and immune response defects are key factors contributing to glaucoma onset. Indeed, both the failure of the trabecular meshwork tissue in the conventional outflow pathway and the neuroinflammation process, which drives the neurodegeneration, seem to be linked to the age-related over-production of free radicals (i.e., mitochondrial dysfunction) and to oxidative stress-linked immunostimulatory signaling. Several previous studies have described a wide range of oxidative stress-related makers which are found in glaucomatous patients, including low levels of antioxidant defences, dysfunction/activation of glial cells, the activation of the NF-κB pathway and the up-regulation of pro-inflammatory cytokines, and so on. However, the intraocular pressure is still currently the only risk factor modifiable by medication or glaucoma surgery. This present review aims to summarize the multiple cellular processes, which promote different risk factors in glaucoma including aging, oxidative stress, trabecular meshwork defects, glial activation response, neurodegenerative insults, and the altered regulation of immune response.

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Section: Trabecular Meshwork (Tm) and Location Of Outflow Resistanmentioning

confidence: 99%

Section: Trabecular Meshwork (Tm) and Location Of Outflow Resistanmentioning

confidence: 99%

Neuroinflammation in Primary Open-Angle Glaucoma

Vernazza

Tirendi

Bassi

et al. 2020

JCM

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“…The primary determinant of IOP is the equilibrium between the production and drainage of AH. AH is produced by the ciliary body, circulates within the anterior chamber, and is then drained through one of two pathways, conventional (trabecular) or uveoscleral (3) (Fig. 1).…”

mentioning

confidence: 99%

Cell atlas of aqueous humor outflow pathways in eyes of humans and four model species provides insight into glaucoma pathogenesis

Zyl

Yan

McAdams

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

158

179

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Increased intraocular pressure (IOP) represents a major risk factor for glaucoma, a prevalent eye disease characterized by death of retinal ganglion cells; lowering IOP is the only proven treatment strategy to delay disease progression. The main determinant of IOP is the equilibrium between production and drainage of aqueous humor, with compromised drainage generally viewed as the primary contributor to dangerous IOP elevations. Drainage occurs through two pathways in the anterior segment of the eye called conventional and uveoscleral. To gain insights into the cell types that comprise these pathways, we used high-throughput single-cell RNA sequencing (scRNAseq). From ∼24,000 single-cell transcriptomes, we identified 19 cell types with molecular markers for each and used histological methods to localize each type. We then performed similar analyses on four organisms used for experimental studies of IOP dynamics and glaucoma: cynomolgus macaque (Macaca fascicularis), rhesus macaque (Macaca mulatta), pig (Sus scrofa), and mouse (Mus musculus). Many human cell types had counterparts in these models, but differences in cell types and gene expression were evident. Finally, we identified the cell types that express genes implicated in glaucoma in all five species. Together, our results provide foundations for investigating the pathogenesis of glaucoma and for using model systems to assess mechanisms and potential interventions.

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“…Visualization of the outflow pathways would be helpful to drive the choice of the MIGS device. 90,91 Among MIGS, iStent (Glaukos Corporation, San Clemente, CA, US, hereafter "first-generation TBS"), and currently, second-generation TBS have emerged as excellent options to achieve sustained IOP reduction without the disadvantages of ocular hypotensive medications. The TBS devices are implanted with an ab-interno procedure, designed to optimize the natural physiologic outflow of aqueous humor.…”

Section: Minimally Invasive Glaucoma Surgery (Migs)mentioning

confidence: 99%

<p>Minimally Invasive Surgery in Mild-to-Moderate Glaucoma Patients in Italy: Is It Time to Change?</p>

Costagliola¹,

Sbordone²,

Gandolfi³

et al. 2020

OPTH

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Medical therapy is the first treatment choice for most patients with glaucoma; however, in a relevant proportion of patients, intraocular pressure (IOP) reduction is achieved with multi-therapy and/or high therapeutic doses. Conventional surgery is the standard alternative to medical therapy when this is not effective or not tolerated. Recently, selective laser trabeculoplasty (SLT) has been advocated as first-line therapy, and "minimally invasive glaucoma surgery" (MIGS) has been developed as safer and less traumatic surgical intervention for patients with glaucoma. Schlemm's canal surgery has emerged as one of the approaches with the most favorable risk-benefit profile for glaucoma patients in need of cataract surgery. However, despite the promising results, use of MIGS in Italy has been extremely low. We aimed to investigate the reasons of the lower-than-expected use of Schlemm's canal-based MIGS devices in Italy, share our perspective on their potential place in therapy, and give practical suggestions to improve the management of glaucoma patients.

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How many aqueous humor outflow pathways are there?

Cited by 53 publications

References 236 publications

Neuroinflammation in Primary Open-Angle Glaucoma

Neuroinflammation in Primary Open-Angle Glaucoma

Cell atlas of aqueous humor outflow pathways in eyes of humans and four model species provides insight into glaucoma pathogenesis

<p>Minimally Invasive Surgery in Mild-to-Moderate Glaucoma Patients in Italy: Is It Time to Change?</p>

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