Purpose: Extraction of tear protein from Schirmer's strip is a prerequisite for the proper identification and screening of biomarkers in dry eye disease. The study compares different methods of extraction of tear proteins from the Schirmer's strip.
Methods: Reflex tear was collected from healthy controls (HC; n = 12), Stevens-Johnson syndrome (SJS; n = 3) and dry eye disease (DED; n = 3) patients using capillary tube. This tear was used to measure the volume absorbed by Schirmer's strip per microliter. Different buffers (6) were used to compare the protein yield from the Schirmer's strip in four different conditions. The tear proteins extracted using the highest protein yield buffer were analyzed by mass spectrometry.
Results: A linear relationship between the tear volume and wetting length was observed (r = 0.0.997, n = 6). The highest yield was observed after incubation of the Schirmer's strip in 100 mM ammonium bicarbonate (ABC) with 0.25% Nonidet P-40(NP-40) at 4°C for an hour (P < 0.00005). The in-solution digestion of tear eluted in the above condition 100 Mm ABC + 0.25% NP-40 with one-hour incubation yielded a total of 2119 proteins in HC, SJS, and DED. The unique protein observed in SJS and DED was 0.6% and 17.9%, respectively. The significantly expressed proteins are associated with innate immune response, proteolysis, wound healing, and defense response.
Conclusion: A method for extraction of protein from Schirmer's strip was optimized for increase in protein yield from the tear sample. SJS and DED tear samples have unique protein signature. The study will aid in better design of tear protein-based experimental study.
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http://dx.doi.org/10.4103/IJO.IJO_2774_22 | DOI Listing |
Invest Ophthalmol Vis Sci
January 2025
GROW Research Laboratory, Narayana Netralaya Foundation, Bangalore, India.
Purpose: Keratoconus (KC) is characterized by irregular astigmatism along with corneal stromal weakness and is associated with altered immune status. Tissue resident microbiomes are known to influence the immune status in other organs, but such a nexus has not been described in ocular conditions. Therefore, we examined the ocular surface microbiome of patients with KC and correlated it to the immune cell and tear molecular factor profiles.
View Article and Find Full Text PDFBMC Ophthalmol
January 2025
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangdong Provincial Key Laboratory of Ophthalmology and Visual Science, Guangdong Provincial Clinical Research Center for Ocular Diseases, Guangzhou, 510060, China.
Background: Herpes simplex keratitis (HSK) is a recurrent inflammatory disease of cornea primarily initiated by type I herpes simplex virus infection of corneal epithelium. However, early diagnosis of HSK remains challenging due to the lack of specific biomarkers. This study aims to identify biomarkers for HSK through tear metabolomics analysis between HSK and healthy individuals.
View Article and Find Full Text PDFOcul Surf
January 2025
Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences, China; Key Laboratory of Ocular Fundus Diseases, Chinese Academy of Medical Sciences, China. Electronic address:
Purpose: The diagnosis and evaluation of dry eye require easy-to-use, precise, and consistent tools in clinical setting. Matrix metalloproteinase 9 (MMP-9) has been proven to be a reliable indicator of dry eye inflammation. The aim of this study is to establish an Eu-time resolved fluorescence immunochromatography (Eu-TRFICO) method for quantitative detection of MMP-9 in human tear based upon widely used Schirmer strips.
View Article and Find Full Text PDFCornea
January 2025
Department of Pulmonology, Trakya University Faculty of Medicine, Edirne, Turkey; and.
Purpose: To investigate the effect of nocturnal chronic hypoxia on the thickness changes of the corneal limbal epithelial area that provides regeneration of the corneal epithelium and ocular surface evaluation parameters in patients with obstructive sleep apnea (OSA).
Methods: All patients diagnosed with OSA and the control group underwent a complete ophthalmological examination, including slit-lamp examination and funduscopy. Tear break-up time, Schirmer test-I, Ocular Surface Disease Index Questionnaire, and anterior segment optical coherence tomography were performed with fluorescein sterile strip for ocular surface evaluation.
Am J Dent
December 2024
Division of General Dentistry, Loma Linda University School of Dentistry, Loma Linda, California, USA,
Purpose: To evaluate the efficacy and subjects' perception of the Modified Schirmer Test (MST) to the traditional Unstimulated Salivary Flow Test (USFT) when measuring salivary flow rate for screening and monitoring patients' dry mouth.
Methods: A total of 100 subjects were enrolled including subjects with and without dry mouth. All subjects answered a brief self-reported survey about dry mouth before and after the two types of saliva tests and their preference for the type of test administered.
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