Biomedical subjects

K S Kunert

Publications and source records attributed to K S Kunert.

5 recordsLinked to original sources

PubMed2001

Trefoil peptides promote restitution of wounded corneal epithelial cells.

The ocular surface shares many characteristics with mucosal surfaces. In both, healing is regulated by peptide growth factors, cytokines, and extracellular matrix proteins. However, these factors are not sufficient to ensure most rapid healing. Trefoil peptides are abundantly expressed epithelial cell products which exert protective effects and are key regulators of gastrointestinal epithelial restitution, the critical early phase of cell migration after mucosal injury. To assess the role of trefoil peptides in corneal epithelial wound healing, the effects of intestinal trefoil factor (ITF/TFF3) and spasmolytic polypeptide (SP/TFF2) on migration and proliferation of corneal epithelial cells were analyzed. Both ITF and SP enhanced restitution of primary rabbit corneal epithelial cells in vitro. While the restitution-enhancing effects of TGF-alpha and TGF-beta were both inhibited by neutralizing anti-TGF-beta-antibodies, trefoil peptide stimulation of restitution was not. Neither trefoil peptide significantly affected proliferation of primary corneal epithelial cells. ITF but not SP or pS2 mRNA was present in rabbit corneal and conjunctival tissues. In summary, the data indicate an unanticipated role of trefoil peptides in healing of ocular surface and demand rating their functional actions beyond the gastrointestinal tract.

Animals↗

PubMed2001

Alteration in goblet cell numbers and mucin gene expression in a mouse model of allergic conjunctivitis.

PURPOSE: To determine whether the number of filled conjunctival goblet cells and mucin gene expression are altered in a mouse model of allergic conjunctivitis. METHODS: A/J mice were sensitized intraperitoneally with cat dander or the peptide P3-1 from the protein Fel d1. Two weeks later, the mice were challenged for 7 consecutive days with eye drops containing the allergens. Conjunctival tissue was harvested at 0, 6, 24, or 48 hours after final antigen challenge. Control samples were naïve animals and mice sensitized with cat dander and challenged with OVA-peptide or PBS. The mean number of filled goblet cells per square millimeter in three forniceal fields for each group was determined in wholemounts of conjunctiva prepared using rhodamine-phalloidin labeling followed by confocal microscopy. RNA was isolated from conjunctiva of the contralateral eye and taken for relative quantitation of mRNA of the goblet cell mucin Muc5AC and the epithelial membrane-spanning mucin Muc4, by real-time RT-PCR. RESULTS: The number of filled goblet cells was significantly decreased with both cat dander and P3-1, after final ocular challenge (P < 0.001). The most significant decrease over naïve mice was seen at 6 hours after final challenge with both allergens. The number of filled goblet cells was still decreased but was returning toward naïve levels at 24 hours (P < 0.05), and at 48 hours no significant difference was seen compared with naïve, PBS-treated, and OVA-peptide-treated control samples. For both cat dander and P3-1, Muc5AC and Muc4 mRNA was found to be decreased at the time of final ocular challenge. The level of Muc5AC mRNA from goblet cells rebounded from the decrease to show an increase over control by 24 hours after final challenge, and by 48 hours, the mRNA level had returned to naïve control range. In contrast, significant increases in Muc5AC mRNA were evident after final control challenge with PBS or OVA-peptide, indicating a potential irritant effect of drop application. The Muc4 mRNA level was significantly reduced at all time points except 24 hours after the last challenge. By comparison with allergen-challenged eyes, no change in Muc4 message levels was noted at any time point in OVA-peptide- or PBS-treated control eyes. CONCLUSIONS: These findings demonstrate that, in the conjunctiva of mice, repetitive application of allergens induces a reduction in the number of filled goblet cells and a decrease in Muc5AC and Muc4 mRNAs. After a period of 24 to 48 hours, the goblet cell number return to naïve levels, and goblet cell mucin mRNA levels return to above or within normal range, indicating a rapid recovery in the mucus secretion system.

Allergens↗

PubMed2000

Analysis of topical cyclosporine treatment of patients with dry eye syndrome: effect on conjunctival lymphocytes.

OBJECTIVE: To study the effect of topical cyclosporine on lymphocyte activation within the conjunctiva of patients with moderate to severe dry eye syndrome (Sjögren and non-Sjögren). METHODS: Biopsy specimens were obtained at baseline and after 6 months of cyclosporine treatment from eyes of 32 patients with moderate to severe dry eye syndrome; 19 were cyclosporine treated (0.05% cyclosporine, n = 13; 0.1% cyclosporine, n = 6) and 13 were vehicle treated. Within this group there were 12 with Sjögren syndrome and 20 with non-Sjögren syndrome. Biopsy tissue was analyzed using immunohistochemical localization of binding of monoclonal antibodies to lymphocytic markers CD3, CD4, and CD8 as well as lymphocyte activation markers CD11a and HLA-DR. RESULTS: In cyclosporine-treated eyes, biopsy results of conjunctivae showed decreases in the number of cells positive for CD3, CD4, and CD8, while in vehicle-treated eyes, results showed increases in these markers, although these differences were not statistically significant. Following treatment with 0.05% cyclosporine, there was a significant decrease in the number of cells expressing the lymphocyte activation markers CD11a (P<.05) and HLA-DR (P<.05), indicating less activation of lymphocytes as compared with vehicle treatment. Within the Sjögren patient subgroup, those treated with 0.05% cyclosporine also showed a significant decrease in the number of cells positive for CD11a (P<.001) as well as CD3 (P<.03), indicating a reduction in number of activated lymphocytes. CONCLUSION: Treatment of dry eye syndrome with topical cyclosporine significantly reduced the numbers of activated lymphocytes within the conjunctiva. Arch Ophthalmol. 2000;118:1489-1496

Administration, Topical↗

PubMed2000

Interleukin-6 levels in tears of contact lens wearers.

The purpose of this study was to evaluate the presence of interleukin-6 (IL-6) in basal tears of contact lens wearers (n = 18) and nonlens wearers (n = 25). Samples (5 microl) were collected with a microcapillary pipette and evaluated using PAGE electrophoresis and immunoblot analysis. Contact lens-wearing patients had a mean IL-6 level of 43.8 +/- 5.3 pg/5 microl compared with nondetectable IL-6 levels throughout the noncontact lens-wearing population. IL-6 in several patients removed from contact lens wear for 6 days became nondetectable. When these patients were returned to wearing lenses, IL-6 levels increased to their original levels within 24 h. The data presented indicate that an ocular medical device may stimulate IL-6 production.

Adult↗

PubMed1999

Microglia increase as photoreceptors decrease in the aging avian retina.

PURPOSE: There is evidence that microglial activation occurs with normal aging in some regions of the brain of rodents. We investigated the pattern of microglia in the retinas of young and aged quail and pigeons to determine if age-related retinal changes evoked migration of microglia into the outer retina. In quail we also investigated the correlation between activated microglia and age-related photoreceptor loss. METHODS: Microglia were identified with the monoclonal antibody QH1 in cryosectioned eyes from pigeons, ages 2 to 20 years (n = 14), and in paraffin sections from six-month (n = 15) and one-year-old quail (n = 30). Rounded microglia in the photoreceptor layer were counted in consecutive 400x fields from temporal to nasal. Photoreceptor counts were made from 10 quail retina flat mounts. The photoreceptor number was compared to the number of microglia in corresponding regions of the same retina. RESULTS: Rounded microglia were detected among the photoreceptors of pigeons and quail. Significantly more of these microglia were found in peripheral than in central regions close to the pecten (pigeon p < 0.002 and quail p < 0.01). Furthermore, more microglial cells were present among peripheral photoreceptors of older quail (p < 0.03) and pigeons (p < 0.05) than in the younger birds. In the peripheral retina of the older quail, microglia were significantly and inversely related to the number of photoreceptors (r2 = 0.9; p < 0.001). CONCLUSIONS: Increased microglial were observed in the peripheral retina of both old quail and old pigeons. In the quail, the rounded (activated) microglia were distributed preferentially in regions of greatest photoreceptor loss. Microglial activation does not appear to be a general phenomenon of the aging retina, but in quail activation appears directly related to photoreceptor loss. It is unclear at this time how the change in microglia shape and distribution is related to their neuroprotective / neurotoxic potential.

Aging↗