Conjunctival goblet cells

CHARACTERIZATION OF SIALOMUCINS EXPRESSED BY HUMAN CONJUNCTIVAL GOBLET CELLS... 

Thus the question to be addressed in this study was, whether a lectin histochemical study on human conjunctival goblet cells could help to explain the discrepancy regarding the assumed key importance of goblet cells for tear sialomucins and the lack of numerical goblet cell reduction in some Dry Eye patients. 

Table 2. Affinity of human conjunctival goblet cells to selected group II and V lectins.

The obtained results are specific for glycoproteins, as glycolipids were washed out during the histological treatment and thus have not to be considered here any further. The overall results on lectin affinity to the human conjunctival goblet cells are summarize in Table 2. As documented there, lectin staining was observed with all but LPA and SNA. 

This study, the first in a series of investigations on goblet cells in different locations, has revealed overall differences in glycoprotein expression of human conjunctival goblet cells and especially sophisticated differences in their sialomucin expression. The obtained data are in accordance with statements in the literature that tear mucins are preferentially produced by the conjunctival goblet cells However, the above data appear to contradict reports in the literature which assume a sole production of tear sialomucins by the conjunctival goblet cells. 

A few reports of others and ourselves are in support of sialomucins being produced not only in conjunctival goblet cells but also in the main and accessory lacrimal gland cells 4,5,11,12 question further the unique importance of conjunctival goblet cell borne... 

The differences in human conjunctival goblet cell group V lectin affinity are of special interest. While LFA results do not differentiate between goblet cells of different activity discrimination appears possible on the basis of the WGA and MAA results. With WGA some goblet cells labeled especially strong. Differences in WGA affinity were never linked... 

Epidermal keratinization and mucous membrane squamous metaplasia respond to both oral and topical vitamin A therapy. Vitamin A exists in three forms retinol, retinal, and retinoic acid.VitaminA increases the mucous production of goblet cells and perhaps the aqueous and lipid components of the tears as well. Tretinoin is a normal metabolite and the carboxylic form of retinol. Retinol is present in tears and the lacrimal gland appears to be its major provider. Retinoic acid has been shown to be effective in ocular surfece disorders such as squamous metaplasia by reversing the corneal and conjunctival keratinization and improving epithelium wound healing rate. 

Kunert KS, Tisdale AS, Stern ME. Effect of cyclosporine ophthalmic emulsion on the number of inflammatory cells and goblet cells in conjunctival biopsies with dry eye. Invest Ophthalmol Vis Sci 1999 44(suppl) S771. 

The palpebral conjunctiva is composed of nonkera-tinized stratified epithelium that decreases in thickness as it proceeds from the eyelid margin. Many mucin-secreting goblet cells are located near the fornix. The epithelium overlies the substantia propria, which consists of delicate connective tissue and blood vessels. Most of the immune system cellular components reside in the substantia propria.The stroma contains lymphocytes, lymphoid follicles, neutrophils, plasma cells, and mast cells, all of which proliferate extensively in conjunctival inflammatory disease. This proliferation leads to the formation of papillae and follicles. 

Dry eye (keratoconjunctivitis sicca) is a chronic condition characterised by dryness of the surface of the eye. It is caused by either a deficiency of conjunctival mucus, due to the absence or significant impairment of the mucin producing goblet cells of the conjunctiva, or tear deficiency, the latter often associated with rheumatoid arthritis. 

While none of the applied lectins showed a strong affinity to non-goblet conjunctival epithelial cells, the experiments with WGA (affinity to glycoproteins with terminal gluco-... 

The construction of the eye is completely different. The outer layer of this mucosa consists of a tiny tear layer of lipids and water which covers a superficial epithelium closed by double layer lipid membranes of 30-70 nm size interconnected by tightjunctions. Three to seven layers of epithelial cells cover the stromal structures of conjunctiva or cornea. The conjunctival surface has interposed cells secreting small amounts of mucin, the so-called goblet cells, which are typically missing within the corneal epithelium. The regeneration of epithelial structures is due to the limbal stem cells located deep in the Vogt s crypts, for the cornea. 

Monkey 6h/day, 5 days/week x 12 months 0.10 0.03, 0.50 0.10, 2.3 0.4 Eye tearing and reddening during exposure to 2.3 ppm seen after 6 week after 1 year had conjunctival irritation but no gross eye lesions. Had trace or mild nasal epithelial hyperplasia, loss of cilia and goblet cells (dose-related), with tracheal involvement at 2.3 ppm. Klonne et al. (1987)... 

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