Effects of azithromycin on gene expression profiles of proinflammatory and anti-inflammatory mediators in the eyelid margin and conjunctiva of patients with meibomian gland disease.

IMPORTANCE: Topical application of azithromycin suppresses expression of proinflammatory mediators while restoring transforming growth factor ß1 (TGF-ß1) levels as evaluated by eyelid margin and conjunctival impression cytology. OBJECTIVE: To explore the effects of azithromycin therapy on expression of proinflammatory and anti-inflammatory mediators in meibomian gland disease (MGD). DESIGN, SETTING, AND PARTICIPANTS: Case-control study performed in a clinic setting from August 17, 2010, to December 31, 2010. Sixteen patients with posterior blepharitis and conjunctival inflammation due to MGD were treated with azithromycin, 1%, drops for 4 weeks. Impression cytology of the lower eyelid margin and tarsal conjunctiva to measure cytokine expression by quantitative real-time polymerase chain reaction as well as tear collection to measure matrix metalloproteinase 9 (MMP-9) activity were performed once in 8 asymptomatic healthy control participants and 5 times in the 16 symptomatic patients (every 2 weeks for 8 weeks), before, during, and after azithromycin treatment. EXPOSURE: Azithromycin, 1%, drops for 4 weeks. MAIN OUTCOMES AND MEASURES: Cytokine expression in the eyelid margin and conjunctiva, and MMP-9 activity in tears. RESULTS: Compared with a 1-time measurement of 8 healthy participants, among 16 symptomatic patients, the mean (SD; 95% CI) fold change of expression of proinflammatory mediators interleukin 1ß (IL-1ß), IL-8, and MMP-9 increased to 13.26 (4.33; 11.14-15.38; P < .001), 9.38 (3.37; 7.73-11.03; P < .001), and 13.49 (4.92; 11.08-15.90; P < .001), respectively, in conjunctival cells and to 11.75 (3.96; 9.81-13.69; P < .001), 9.31 (3.28; 7.70-10.92; P < .001), and 11.52 (3.50; 9.81-13.24; P < .001), respectively, in the eyelid margin of patients with MGD. In contrast, the mean (SD; 96% CI) fold change of expression of TGF-ß1 messenger RNA (mRNA) decreased to 0.58 (0.25; 0.46-0.70; P = .02) and 0.63 (0.14; 0.56-0.70; P = .02) in conjunctival and eyelid margin cells, respectively, of patients with MGD. Azithromycin, 1%, caused a change in the expression pattern of these mediators toward normal levels during 4 weeks of treatment. Levels of IL-1ß, IL-8, and MMP-9 mRNA remained suppressed, although they rebounded toward pretreatment values 4 weeks after azithromycin withdrawal. Expression of TGF-ß1 increased during treatment and remained at levels similar to the healthy controls after drug withdrawal. Change in tear MMP-9 activity was similar to the pattern of MMP-9 transcripts. CONCLUSIONS AND RELEVANCE: While the study did not control for potential confounding factors over time independent of the intervention that may have contributed to the results, topical azithromycin suppressed expression of proinflammatory mediators and increased expression of TGF-ß1 to normal levels. Increased TGF-ß1 expression may contribute to the anti-inflammatory activity of azithromycin in MGD.

Ocular surface extracellular DNA and nuclease activity imbalance: a new paradigm for inflammation in dry eye disease.

PURPOSE: We determined whether nucleases are deficient in the tear fluid of dry eye disease (DED) patients, and whether this causes extracellular DNA (eDNA) and neutrophil extracellular trap (NET) accumulation in the precorneal tear film, thus causing ocular surface inflammation. METHODS: Exfoliated cells adhered to Schirmer test strips were collected on glass slides, and immunofluorescence confocal microscopy was used to evaluate neutrophils, eDNA, NETs, and their molecular components. Similar experiments were performed with mucoid films collected from the inferior conjunctival fornix or bulbar conjunctiva. We used quantitative PCR to evaluate eDNA signaling pathways and inflammatory cytokine expression. We also determined the amount of ocular surface eDNA and evaluated tear fluid nuclease activity. RESULTS: eDNA, NETs, and neutrophils were present on the ocular surface in DED patients and abundant in mucoid films. NETs consisted of eDNA, histones, cathelicidin, and neutrophil elastase. Tear fluid nuclease activity was decreased significantly in DED patients, whereas the amount of eDNA on the ocular surface was increased significantly. Expression of genes downstream of eDNA signaling, such as TLR9, MyD88, and type I interferon, as well as the inflammatory cytokines interleukin-6 and tumor necrosis factor-α, was significantly increased in DED patients. CONCLUSIONS: Extracellular DNA production and clearance mechanisms are dysregulated in DED. Nuclease deficiency in tear fluid allows eDNA and NETs to accumulate in precorneal tear film, and results in ocular surface inflammation. These findings point to novel therapeutic interventions in severe DED based on clearance of eDNA, NETs, and other molecular components from the ocular surface.

Treatment of severe keratoconjunctivitis sicca by parotid duct transposition after tympanic neurectomy in rabbits.

PURPOSE: To investigate the feasibility of parotid duct transposition after tympanic neurectomy to treat severe keratoconjunctivitis sicca (KCS) in rabbits. METHODS: Thirty rabbits were divided into three groups in experiment 1. One eye was operated on, and the contralateral eye served as the control. In the KCS group, the lacrimal gland, harderian gland, and nictitating membrane were removed. In the group with parotid duct transposition (DT), the parotid duct was transposed into the lower conjunctival fornix. In the group with parotid duct transposition after tympanic neurectomy (DTTN), the tympanic nerve was resected in addition to parotid duct transposition. Schirmer test was performed and density of corneal staining was determined monthly after surgery, and goblet cell density was measured at postoperative month 3. In experiment 2, the tympanic nerve was resected on one side in 12 rabbits. Both sides of the parotid gland were resected for histopathology at intervals of 2 months to 1 year after surgery. RESULTS: Tear secretion from operated eyes at rest increased significantly after surgery in the treatment groups compared with the KCS group. Tear secretion from operated eyes after chewing was significantly lower in the DTTN than in the DT group. The corneal staining scores were higher in the operated than in the control eyes of the three groups, without significant difference among the operated eyes. Parotid gland atrophy on the operated side occurred at postoperative month 4 and recovered to normal 1 year after surgery. CONCLUSIONS: Parotid duct transposition after tympanic neurectomy could effectively reduce gustatory epiphora but may be insufficient to promote ocular surface health.

Characterization of beta-hexosaminidase secretion in rabbit lacrimal gland.

The present study was aimed at validating the use of the lysosomal enzyme beta-hexosaminidase as a marker of secretory function in cultured rabbit lacrimal gland acinar cells. The secretory response and morphological characteristics of isolated acinar cells cultured in a serum-free medium supplemented with an extracellular matrix extract were monitored over time as part of optimization of our culturing protocol. Secreted beta-hexosaminidase activity was analyzed and compared with that of another lysosomal enzyme, cathepsin B, as well as protein secreted into the media, w or w/o the presence of secretagogues or protein kinase C activators and inhibitors. Lacrimal gland fluid was obtained from pilocarpine stimulated rabbits, and the activities of beta-hexosaminidase and cathepsin B were measured. A membrane fraction and a soluble fraction were obtained from isolated acinar cells and used for kinetic studies of beta-hexosaminidase in comparison with that released from cultured cells, in the lacrimal gland fluid and in serum. Optimal secretory response was obtained when the cells had been in culture for 2-3 days, coinciding with the formation of acinus-like structures. Stimulation of the cultured cells by carbachol or phorbol esters resulted in a more than 3-fold increase of beta-hexosaminidase release over basal, whereas no effect on cathepsin B release could be detected. Treatment with the protein kinase C inhibitor, chelerythrine chloride, significantly decreased the carbachol and phorbol ester-stimulated secretion. Cathepsin B could not be detected in rabbit lacrimal fluid, but beta-hexosaminidase was easily measured in quantities corresponding to as low as 0.4 microl of tear fluid. Using 4-methylumbelliferyl N-acetyl-beta-D-glucosaminide as a substrate for beta-hexosaminidase, the K(m) in lacrimal gland fluid (1.22+/-0.15 mM) was not significantly different from that of the membrane-associated fraction, the soluble fraction, rabbit serum or activity secreted from cultured cells. Beta-hexosaminidase is secreted by rabbit lacrimal gland, in vivo, and by acinar cells in primary culture, whereas cathepsin B is not secreted under the conditions described. Beta-hexosaminidase therefore provides a versatile marker for secretion in studies of tear production utilizing the rabbit as a model. Our results also indicate that PKC is an important regulator of rabbit lacrimal gland secretion.

[Tear enzymes in the treatment of an experimental alkaline corneal burn with gordox]. / Fermenty slezy pri lechenii éksperimental'nogo shchelochnogo ozhoga rogovitsy gordoksom.

The study of the influence of hordox, in treatment of experimental alkaline burn of the cornea, on the activity of trypsin-like proteases, elastases, callicreine, beta-N-acetylglucosaminidase and beta-glucuronidase in a tear fluid has shown that activity of these enzymes in a tear after burn remarkably increases, especially within first 24 hours and at the end of the second week after burn. In treatment by hordox, the activity of all enzymes in the tear, except elastase, reduces as compared with untreated animals, that speaks about antiinflammatory action of the preparation. On the basis of the data obtained it is suggested that investigation of hydrolytic enzymes in a tear can serve as a criterion for aimed correction of proteolysis in inflammatory processes in the cornea.

Effect of topical anesthesia on secretion of lysozyme and lysosomal enzymes in human tears.

Unilateral topical anesthesia affected the secretion of human tear fluid and its concentrations of lysozyme and lysosomal enzymes. Results of a Schirmer's test with 0.4% oxybuprocaine showed that topical anesthesia reduced the mean test value by 47% and the secretion of protein, lysozyme, acid phosphatase, and N-acetyl-beta-D-glucosaminidase by 30%, 45%, 31%, and 33%, respectively. These results indicated that the paper strip induced reflex secretion from only the stimulated eye. The enzyme activity of lysozyme per fluid volume in tears from anesthetized eyes was as high as that from eyes without anesthesia, while acid phosphatase and N-acetyl-beta-D-glucosaminidase had higher activities. The amount of protein in the tear fluid was higher in anesthetized eyes than in unanesthetized eyes. Enzyme activity of lysozyme per protein of the tear fluid in the anesthetized eyes was lower than in the eyes without anesthesia, while acid phosphatase and N-acetyl-beta-D-glucosaminidase had higher activities per protein in the eyes with anesthesia. These findings disclosed that the concentrations of total protein, acid phosphatase, and N-acetyl-beta-D-glucosaminidase increased, while lysozyme value was constant when the tear secretion decreased.