Localization of alpha 2-adrenergic receptor subtypes in the anterior segment of the human eye with selective antibodies.

Purpose: To develop antibodies that selectively recognize each of the alpha 2-adrenergic receptor (AR) subtypes and to determine the expression and localization of these subtypes in the anterior segment of the human eye.

Methods: Recent studies have shown that there are three subtypes of the alpha 2-ARs, termed alpha 2-C10 (alpha 2A), alpha 2-C2 (alpha 2B), and alpha 2-C4 (alpha 2C). Polymerase chain reaction was used to amplify portions of these receptors fused (in-frame) to a cDNA encoding glutathione-S-transferase (GST).

Isolation and culture of human trabecular meshwork cells by extracellular matrix digestion.

Like corneal endothelial cells, human trabecular meshwork cells are believed to be of neural crest origin, but demonstrate physiological properties and an antithrombogenic surface similar to vascular endothelial cells. One current method for isolating trabecular meshwork cells utilizes the motile nature of these cells to migrate away from a trabecular meshwork explant in culture to more distal regions of the culture dish. This 'outgrowth' technique is limited in practice by the relatively small number of cells that migrate per explant per unit time, thus hindering the ability to gather sufficient numbers of cells for comprehensive experimentation.

Localization of aquaporin CHIP in the human eye: implications in the pathogenesis of glaucoma and other disorders of ocular fluid balance.

Purpose: The existence of integral membrane proteins that serve as selective water channels has been postulated to explain the movement of water across plasma membranes. Aquaporin CHIP (channel-forming integral membrane protein of 28 kd) is the first such channel to be characterized and is abundant in human erythrocytes and a variety of secretory and absorptive epithelia of the rat. Because disturbances in the movement of water characterize several ocular diseases, the distribution of CHIP in the human eye was studied.

Dexamethasone decreases tissue plasminogen activator activity in trabecular meshwork organ and cell cultures.

Previously, we observed that dexamethasone decreased the extracellular activity of some matrix metalloproteinases and tissue plasminogen activator in trabecular meshwork containing organ explants and cell cultures. We have extended these studies to determine whether the decrease in extracellular tissue plasminogen activator activity is the result of a decrease in the expression of tissue plasminogen activator, a change in the extracellular level of plasminogen activator inhibitor-1, or a combination of both. We demonstrate that dexamethasone decreases the steady-state levels of tissue plasminogen activator mRNA by 75% in trabecular meshwork cells using Northern blot analysis, and show that this occurs concurrently with a 31% increase in the levels of extracellular plasminogen activator inhibitor-1 as determined by enzyme-linked immunosorbent assay analysis.

Corticosteroid treatment and trabecular meshwork proteases in cell and organ culture supernatants.

Steroid-induced glaucoma is believed to result from increased aqueous outflow resistance and evidence suggests that this is the result of an excess accumulation of extracellular matrix components. This accumulation could result from an imbalance in the natural turnover of these components. We have investigated the effect of corticosteroid treatment of trabecular meshwork (TM) organ and cell cultures on the extracellular activities of the matrix metalloproteinases and plasminogen activators.