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Validation of the flush method as an alternative to basal or reflex tear collection
Maria Markoulli1, Eric Papas, Andrea Petznick
1Brien Holden Vision Institute, Sydney, Australia. m.markoulli@brienholdenvision.org
Insights
The flush tear collection method is a faster, convenient alternative to basal tear collection for tear composition analysis. It yields similar protein profiles and proportions, validating its use in research.
Area of Science:
- Ophthalmology
- Biochemistry
- Proteomics
Background:
- Tear collection methods are crucial for ocular surface disease research.
- Basal and reflex tear collection can be time-consuming and invasive.
- A simpler, faster tear collection technique is needed for tear composition analysis.
Purpose of the Study:
- To validate the
- flush
- tear collection technique as a viable alternative to basal and reflex tear collection methods.
Main Methods:
- Tear samples were collected from 16 healthy individuals using basal, reflex, and flush techniques.
- Total protein content (TPC) and immunoglobulin A (IgA) concentrations were measured.
- Protein profiles were analyzed using SDS-PAGE and mass spectrometry (MS).
Main Results:
- Flush tear collection yielded significantly higher collection rates compared to basal and reflex methods.
- TPC was lower in flush tears than basal and reflex tears, but IgA concentration as a percentage of TPC was similar between flush and basal tears.
- SDS-PAGE and MS revealed comparable protein profiles between basal and flush tears.
Conclusions:
- The flush tear collection method is a convenient and faster alternative to basal tear sampling.
- It provides similar protein composition and proportions, making it suitable for tear analysis studies.
- This technique offers a practical solution for research requiring tear composition analysis.
Purpose:
To validate the more easily applicable "flush" tear collection technique as a viable alternative to basal and reflex tear collection.
Materials And Methods:
Total protein content (TPC) and immunoglobulin A (IgA) concentrations were determined in the basal, reflex, and flush tears of 16 healthy non-contact lens wearers. The overall protein profile was established using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and mass spectrometry (MS).
Results:
Collection-rates were 4.6 ± 6.7 μl/min, 13.9 ± 11.1 μl/min, and 25.7 ± 12.4 μl/min for the basal, reflex, and flush tears, respectively. TPC was 7.14 ± 2.22 mg/mL, 6.01 ± 2.11 mg/mL, and 3.79 ± 1.51 mg/ mL for basal, reflex, and flush tears, respectively, with flush tears being significantly less concentrated than basal (p = 0.001) and reflex (p = 0.008). IgA concentration was 1.04 ± 0.29 mg/ mL, 0.64 ± 0.26 mg/mL, and 0.65 ± 0.23 mg/mL for basal, reflex, and flush tears, respectively, with basal tears being significantly more concentrated (p < 0.001). As a percentage of TPC, IgA represented 19.8 ± 14.9%, 11.4 ± 3.9%, and 19.8 ± 8.7% for basal, reflex, and flush, respectively. The flush was not significantly different to basal (p = 1.00) but significantly greater than reflex (p = 0.02). SDS-PAGE showed the same tear profiles for basal and flush tears. MS identified the most abundant proteins in all tear types.
Conclusions:
The flush method allows much faster collection than basal secretion sampling but returns essentially the same spectrum of proteins in similar proportions. This behavior is confirmation that the flush technique has utility as a more convenient alternative to basal tear sampling in studies involving composition analysis.
