Role of lactoferrin in the tear film

Flanagan, Judith; Willcox, Mark

doi:10.1016/j.biochi.2008.07.007

Cited by 174 publications

(121 citation statements)

References 102 publications

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“…For its quantification some methods have been adopted, 15,18,19 with inhomogeneous results being obtained. Lactoferrin is a single-chain polipeptide with important bacteriostatic activity, 20 which also represents an index of lachrymal gland function. Its determination in tears has been conducted in the past by techniques, 21,22 currently abandoned.…”

Section: Discussionmentioning

confidence: 99%

“…For patients, the inclusion criteria were a Schirmer test I value higher than 10 mm/5 min, a tear film break-up time (TFBUT) value p10 s, mild subjective symptoms of ocular discomfort as evaluated by an OSDI questionnaire 11 (score [12][13][14][15][16][17][18][19][20][21][22][23][24], and use of tear substitutes only, for treatment, which were suspended for at least 3 days before tear collection.…”

Section: Subjectsmentioning

confidence: 99%

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Tear proteomics in evaporative dry eye disease

Versura

Nanni

Bavelloni

et al. 2010

Eye

141

114

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Purpose: To analyze tear protein variations in patients suffering from dry eye symptoms in the presence of tear film instability but without epithelial defects. Methods: Five microlitres of non-stimulated tears from 60 patients, suffering from evaporative dry eye (EDE) with a break-up time (BUT) o10 s, and from 30 healthy subjects as control (no symptoms, BUT 410 s) were collected. Tear proteins were separated by mono and bi-dimensional SDS-PAGE electrophoresis and characterized by immunoblotting and enzymatic digestion. Digested peptides were analyzed by liquid chromatography coupled to electrospray ionization quadrupole-time of flight mass spectrometry followed by comparative data analysis into Swiss-Prot human protein database using Mascot. Statistical analysis were performed by applying a t-test for independent data and a MannWhitney test for unpaired data (Po0.05). Results: In EDE patients vs controls, a significant decrease in levels of lactoferrin (data in % ± SD): 20.15 ± 2.64 vs 24.56 ± 3.46 (P ¼ 0.001), lipocalin-1: 14.98±2.70 vs 17.73±2.96 (P ¼ 0.0001), and lipophilin A-C: 2.89±1.06 vs 3.63±1.37 (P ¼ 0.006) was revealed, while a significant increase was observed for serum albumin: 9.45 ± 1.87 vs 3.46 ± 1.87 (P ¼ 0.0001). No changes for lysozyme and zinc a-2 glycoprotein (P ¼ 0.07 and 0.7, respectively) were shown. Proteomic analysis showed a downregulation of lipophilin A and C and lipocalin-1 in patients, which is suggested to be associated with post-translational modifications. Conclusions: Data show that tear protein changes anticipate the onset of more extensive clinical signs in early stage dry eye disease.

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Section: Discussionmentioning

confidence: 99%

Section: Subjectsmentioning

confidence: 99%

Tear proteomics in evaporative dry eye disease

Versura

Nanni

Bavelloni

et al. 2010

Eye

141

114

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“…46 PIP was found to be decreased in patients with MGD, which is involved in water transport function. 14 A recently conducted study in Sjögren's syndrome tears also showed a few similar proteins, which were detected in our current study, including Ig alpha-2 chain C, Ig alpha-1 chain C, zinc-alpha-2 glycoprotein, and polymeric-immunoglobulin.…”

Section: Discussionmentioning

confidence: 99%

iTRAQ Quantitative Proteomics in the Analysis of Tears in Dry Eye Patients

Srinivasan

Thangavelu

Zhang³

et al. 2012

Invest. Ophthalmol. Vis. Sci.

109

119

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PURPOSE. We analyzed the change in protein expression of tear film proteins in dry eye (DE) and non-DE (NDE) patients using isobaric tag for relative and absolute quantitation (iTRAQ) technology.METHODS. We categorized 24 participants into NDE, and mild (MDE), moderate-to-severe (MSDE), and mixed (MXDE) DE on the basis of clinical DE tests. Tear samples (n ¼ 6 subjects/ group) were collected using Schirmer's strips. Proteins were extracted from strips and were quantified using the Bradford assay. Protein from each sample was pooled as internal standard (IS), and 20 lg protein from each sample and the IS were digested and labeled with different tandem mass tag (TMT) isobaric mass tag labeling reagent. The reaction was quenched and the labeled peptides were mixed. Samples were injected for liquid chromatography-mass spectrometry (LC/MS/ MS) analysis on the Orbitrap mass spectrometer. Bioinformatic analyses were performed using protein information resource (PIR). RESULTS.Combined results showed a total of 386 proteins in tears as determined by the iTRAQ experiments. An average of 163 proteins was detected in each of 6 biologic replicates. Of those, 55% were detected 6 times and 90% were detected multiple times (>2). In addition to the down-regulation of commonly reported proteins, such as lipocalin-1, lysozyme, and prolactin-inducible protein across all sub groups of DE, a number of proteins were significantly differentially regulated in MSDE and other subgroups of DE. A greater number of proteins were down-regulated in MSDE versus MDE, and the specific functions involved include response to stimulus (8 vs. 6 proteins), immune system process (6 vs. 4), regulation of biologic processes (3 vs. 3), and ion transport (2 vs. 2).CONCLUSIONS. iTRAQ is one of the newest tools for quantitative mass spectrometry in tear proteome research. Differences in the protein ratios can be detected between normal and DE patients. PIR is a useful resource to interpret pathways and functions of proteins. (Invest Ophthalmol Vis Sci. 2012; 53:5052-5059) DOI:10.1167/iovs.11-9022 T he Dry Eye Workshop in 2007 defined dry eye (DE) as a multifactorial ocular surface disease diagnosed by symptoms of discomfort, and signs of visual disturbance, tear film instability, and ocular surface damage, accompanied by increased osmolarity of the tear film and ocular surface inflammation.1 It is evident from the definition that the tear film and ocular surface are altered in DE disease. The tear film serves/performs a variety of functions and is composed of various substances, including proteins, lipids, mucins, salts, and other organic molecules.2 The aqueous component constitutes the majority of the tear layer, and the proteins in the tear film are believed to have a key role in the protection of the external surface from potential pathogens, and also are involved in modulation of wound healing process. [3][4][5][6] The major source of tear proteins is the secretory acinar cells of the lacrimal gland, including the primary proteins of the tear film: lyso...

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“…74 This suggests that certain defence mechanisms against infection exist in the healthy eye that are absent from laboratory culture conditions. Although many P. aeruginosa strains grow readily in undiluted tear fluid despite its antimicrobial components such as lactoferrin and lysozyme, 75,76 tear fluid can still protect corneal epithelial cells against them. 77,78 This is thought to be due to the tear fluid acting directly upon corneal epithelial cells to make them more resistant to P. aeruginosa invasion and cytotoxicity.…”

Section: Pattern Recognition Mechanisms Activated By Microbial Pathogmentioning

confidence: 99%