1. Selected Topics in Biochemistry Relevant to the Eye.- 2. Tears.- 3. Cornea.- 4. Aqueous, Iris-Ciliary Body, and Trabeculum.- 5. Lens.- 6. Vitreous.- 7. Retina.

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Biochemistry of the Eye

Multiple physiological fluid movements are involved in vision. Here we define the cellular and subcellular sites of aquaporin (AQP) water transport proteins in human and rat eyes by immunoblotting,...

Aquaporins in complex tissues: distribution of aquaporins 1–5 in human and rat eye

PURPOSE The anterior chamber of the eye is a highly specialized structure delimited by the cornea, lens, and iris It contains the aqueous humor, secreted by the ciliary body and drained by the trabecular meshwork Alteration of aqueous humor homeostasis plays a major role in the pathogenesis of glaucoma The trabecular meshwork is the target tissue of glaucoma in the anterior chamber, and the development and progression of glaucoma are accompanied by accumulation of oxidative damage in this tissue This study was conducted to comparatively evaluate the sensitivity to oxidative stress of anterior chamber tissues including the cornea, iris, and trabecular meshwork METHODS Cornea, iris, and trabecular meshwork fragments collected from six cornea donors were either left untreated or treated with hydrogen peroxide Oxidative damage was determined by evaluating nucleotide oxidative modifications (8hydroxy-2-deoxyguanosine) and apurinic alkali‐fragile sites by capillary electrophoresis RESULTS The results indicated that the basal level of oxidative nucleotide modifications was higher in the cornea than in the iris and trabecular meshwork The trabecular meshwork was the most sensitive tissue to oxidative damage, as after exposure to hydrogen peroxide both markers of oxidative damage dramatically increased in the trabecular meshwork but not in the cornea and iris CONCLUSIONS Because the cornea and iris are directly exposed to light, they possess antioxidant defense mechanisms that are not activated in the trabecular meshwork The peculiar sensitivity of the trabecular meshwork to oxidative stress is consistent with the damage selectively induced in it, triggering glaucoma’s pathogenic cascade (Invest Ophthalmol Vis Sci 2009; 50:5251‐5258) DOI:101167/iovs09-3871

Sensitivity of ocular anterior chamber tissues to oxidative damage and its relevance to the pathogenesis of glaucoma.

A large Caucasian family is presented, in which a juvenile-onset form of open-angle glaucoma is transmitted in an autosomal dominant fashion. Sixteen affected family members were identified from 31 at-risk individuals descended from the affected founder. Affected patients developed high intraocular pressures (sometimes > 40 mm Hg) within the first 2 decades of life. Linkage analysis between the disease phenotype and 12 microsatellite repeat markers located on chromosome 1q gave a maximum lod score of 8.38 at a recombination fraction of zero for marker D1S210. Analysis of recombinant haplotypes suggests a total inclusion region of about 14 cM between markers D1S194 and D1S218 at 1q21-q31. This represents the second juvenile-glaucoma family, in which the disease has been mapped to the long arm of chromosome 1.

Mapping of a gene for autosomal dominant juvenile-onset open-angle glaucoma to chromosome Iq.

Aqueous humour (AH) is an important intraocular fluid responsible for the supply of nutrients to and removal of metabolic wastes from the avascular tissues of the eye It is also indispensable for the maintenance of the optical properties of the eye The fluid dynamics of AH are frequently associated with the potentially blinding disease called glaucoma Pharmacological treatment of glaucoma generally aims to lower the intraocular pressure by reducing AH formation However, the mechanism underlying the formation of AH is still not well understood Understanding the mechanism of AH formation and its regulation is paramount to develop rational and target specific drugs for the treatment of glaucoma It is now generally believed that AH is formed mostly by active transport of ions and solutes across the ciliary epithelium Many studies have been carried out in the past half a century to understand these transport processes In the past several years, new information has emerged and a comprehensive review of these new developments is necessary This review covers the ion transports in the ciliary epithelium, including the possible roles of sodium, chloride and bicarbonate ions as the driving forces It also examines the current ionic models for AH formation and its regulation from a cellular transport perspective

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1444-0938.2002.tb02384.x

The mechanism of aqueous humour formation

ATPases of ciliary epithelium: cellular and subcellular distribution and probable role in secretion of aqueous humor.

A bovine eye perfusion system was developed for detoxification studies. The viability of the system was examined by two criteria: the permeability of the aqueous-blood barrier to protein, ...

Kenichi Kishida

Papers

ATPases of ciliary epithelium: cellular and subcellular distribution and probable role in secretion of aqueous humor.

Glutathione depletion and oxidative stress: study with perfused bovine eye.