New perspectives in aqueous humor secretion and in glaucoma: The ciliary body as a multifunctional neuroendocrine gland

Coca‐Prados, Miguel; Escribano, Julio

doi:10.1016/j.preteyeres.2007.01.002

Cited by 115 publications

(80 citation statements)

References 146 publications

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“…[16][17][18] Recently, Oliveira et al 13 found a significant positive correlation between AL and CBT in 75 eyes with UBM. However, their results may be influenced by some factors: only 22 of 75 eyes in the study group of Oliveira et al were normal.…”

Section: Discussionmentioning

confidence: 99%

Ciliary body thickness in unilateral high axial myopia

Müftüoğlu

Hoşal

Zílelíoğlu

2008

Eye

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Purpose To compare the thickness of the ciliary bodies of eyes with unilateral high axial myopia with their relatively normal fellow eyes. Methods A total of 19 patients with unilateral high axial length (AL) were included in the study. Mean patient age was 28. 4±10.4 (11-44) years. All eyes underwent ultrasound biometry to measure the AL, and ultrasound biomicroscopy to measure the anterior chamber depth, ciliary body thickness (CBT), and ciliary process thickness (CPT), ciliary muscle thickness (CMT). The results were compared between each subject's high myopic eye and relatively normal fellow eye. Results The mean AL was 27.24±1.52 mm (range: 25.16-30.21 mm) in high myopic eyes and 23.64 ± 0.86 mm (range: 22.47-25.10 mm) in normal fellow eyes. The median ± 95% confidence interval of CBT, CPT, and CMT was 1.350±0.034, 0.626±0.072, and 0.698±0.057 mm, respectively, in high myopic eyes and 1.211±0.050, 0.535±0.064, and 0.644±0.065 mm, respectively, in normal fellow eyes. The anterior chamber depth, CBT, CPT, and CMT were significantly higher in myopic eyes compared with their relatively normal fellow eyes (Po0.05). CMT significantly increased with age in both groups (Po0.05). There was no significant correlation between age and CBT in both the groups (P40.05). Conclusion The CBT, CMT, and CPT are significantly higher in eyes with unilateral high axial myopia than in their relatively normal fellow eyes.

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Section: Discussionmentioning

confidence: 99%

Ciliary body thickness in unilateral high axial myopia

Müftüoğlu

Hoşal

Zílelíoğlu

2008

Eye

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“…It has been demonstrated that the ciliary epithelium is a source of proteins in the aqueous humor (Escribano et al 1995;Escribano and Coca-Prados 2002), and that several glaucoma-related genes are expressed in this tissue, most notably myocilin and CYP1B1 (CocaPrados and Escribano 2007;Janssen et al 2012). In addition, the ciliary epithelium produces a variety of neuroendocrine factors, such as natriuretic peptides, neurotensin, and somatostatin (Coca-Prados and Escribano 2007). Their potential role in regulating the production of aqueous humor and their influence on outflow resistance is an intriguing topic for further research.…”

Section: Differential Gene Expression In Structures Of the Anterior Eyementioning

confidence: 99%

“…In the anterior chamber, the major structures regulating production and outflow of aqueous humor, including the ciliary body, the trabecular meshwork, and Schlemm's canal, can be affected (Johnson 2006;Coca-Prados and Escribano 2007;Tamm 2009). The retina and, in particular, the ganglion cells themselves (Danias et al 2003;Jakobs et al 2005;Schlamp et al 2006;Morgan 2012) are affected.…”

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confidence: 99%

Differential Gene Expression in Glaucoma

Jakobs

2014

Cold Spring Harbor Perspectives in Medicine

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In glaucoma, regardless of its etiology, retinal ganglion cells degenerate and eventually die. Although age and elevated intraocular pressure (IOP) are the main risk factors, there are still many mysteries in the pathogenesis of glaucoma. The advent of genome-wide microarray expression screening together with the availability of animal models of the disease has allowed analysis of differential gene expression in all parts of the eye in glaucoma. This review will outline the findings of recent genome-wide expression studies and discuss their commonalities and differences. A common finding was the differential regulation of genes involved in inflammation and immunity, including the complement system and the cytokines transforming growth factor b (TGFb) and tumor necrosis factor a (TNFa). Other genes of interest have roles in the extracellular matrix, cell -matrix interactions and adhesion, the cell cycle, and the endothelin system.

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“…TRPV4 | ciliary body | intraocular pressure | aqueous humor | glaucoma F ormation of aqueous humor in the vertebrate eye takes place within the ciliary body (CB), a highly folded tissue consisting of pigmented epithelial (PE) cells, nonpigmented epithelial (NPE) cells, and the ciliary muscle (1,2). Together, PE cells, which face the vascularized stroma and represent a forward continuation of the retinal pigment epithelium (RPE), and NPE cells, which face the posterior chamber (lumen) of the eye and extend the neuronal retina, form the blood-aqueous barrier and regulate the production and secretion of aqueous humor.…”

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confidence: 99%

Differential volume regulation and calcium signaling in two ciliary body cell types is subserved by TRPV4 channels

Lakk

Frye

et al. 2016

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

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Fluid secretion by the ciliary body plays a critical and irreplaceable function in vertebrate vision by providing nutritive support to the cornea and lens, and by maintaining intraocular pressure. Here, we identify TRPV4 (transient receptor potential vanilloid isoform 4) channels as key osmosensors in nonpigmented epithelial (NPE) TRPV4 | ciliary body | intraocular pressure | aqueous humor | glaucoma F ormation of aqueous humor in the vertebrate eye takes place within the ciliary body (CB), a highly folded tissue consisting of pigmented epithelial (PE) cells, nonpigmented epithelial (NPE) cells, and the ciliary muscle (1, 2). Together, PE cells, which face the vascularized stroma and represent a forward continuation of the retinal pigment epithelium (RPE), and NPE cells, which face the posterior chamber (lumen) of the eye and extend the neuronal retina, form the blood-aqueous barrier and regulate the production and secretion of aqueous humor. The aqueous fluid supplies nutrients and oxygen to nonvascularized tissues (lens, cornea, and trabecular meshwork) and is ultimately drained through the ciliary muscle and the trabecular meshwork in the anterior chamber of the eye. Aqueous secretion is subserved by the unidirectional transport of ions and water through gap junctions between PE cells and NPE cells (3,4) and is driven by the osmotic gradient generated by Na + /K + exchange across basolateral NPE membranes (2-5). Despite the critical dependence of aqueous humor secretion on osmotic pressure (1, 4, 6), the molecular mechanism through which NPE and PE cells sense and regulate changes in volume is not well understood.In addition to osmotic shifts, CB cells experience mechanical forces associated with mean and time-varying aspects of intraocular pressure (IOP), a phenomenon that reflects balanced regulation of fluid secretion from NPE cells and its drainage from the anterior eye. Excessive IOP elevations represent the primary, and major, risk factor for contracting glaucoma (6, 7), an optic neuropathy that represents the second leading cause of blindness in the world. Therefore, aqueous secretion is often targeted by antiglaucoma medications that include β-adrenergic receptor antagonists, carbonic anhydrase inhibitors, α 2 -adrenergic agonists, and muscarinic cholinergic agonists (7). A key question, however, is whether CB cells themselves are able to sense force mediated by membrane stretch induced by hydrostatic pressure or swelling, and what such mechanisms might be.Here, we identify a key osmosensor in CB as transient receptor potential channel vanilloid isoform 4 (TRPV4), a polymodal nonselective cation-permeable channel that has been implicated in mechanotransduction (8, 9) as well as regulation of paracellular permeability in multiple epithelial tissues (10-15). Intriguingly, we found that TRPV4 is selectively distributed across CB by being confined to the NPE and excluded from PE cells. We characterized the functional role of TRPV4 as the predominant NPE swelling sensor and determined its contribution to...

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New perspectives in aqueous humor secretion and in glaucoma: The ciliary body as a multifunctional neuroendocrine gland

Cited by 115 publications

References 146 publications

Ciliary body thickness in unilateral high axial myopia

Ciliary body thickness in unilateral high axial myopia

Differential Gene Expression in Glaucoma

Differential volume regulation and calcium signaling in two ciliary body cell types is subserved by TRPV4 channels

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