Comparative analysis of human tear fluid and aqueous humor proteomes.

PURPOSE: Technological advancements allowing for the analysis of low-volume samples have led to the investigation of human tear fluid and aqueous humor (AH) as potential biomarker sources. However, acquiring AH samples poses significant challenges, making human tear fluid a more accessible alternative. This study aims to compare the protein compositions of these two biofluids to evaluate their suitability for biomarker discovery. METHODS: Paired tear and AH samples were collected from 20 patients undergoing cataract surgery. Tear samples were collected using Schirmer strips prior to surgery, and AH samples were collected from the anterior chamber immediately after corneal incision. Proteins were extracted and analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). RESULTS: A total of 481 proteins were identified in greater than 50% of the tear samples, and 191 proteins were detected in greater than 50% of the AH samples. Of these proteins, 82 were found to be common between the two biofluids, with ALB, LTF, TF, LCN1, and IGKC being the most abundant. CONCLUSION: Although tear fluid and the AH are functionally independent and physically separated, many of the proteins detected in AH were also detected in tears. This direct comparison of the proteomic content of tear fluid and AH may aid in further investigation of tear fluid as a source of readily accessible biomarkers for various human diseases.

Intra-population differences of apolipoproteins in the aqueous humor.

BACKGROUND: Evidence suggests that proteins related to lipid metabolism, such as apolipoproteins, play an important role in the maintenance of normal vision. While several members of the apolipoprotein family are abundant in human aqueous humor (AH), their study remains difficult due to the AH's small volume, low protein concentration, and the invasive nature of sample collection. In this study, we report the use of Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS) to discover associations between AH apolipoproteins and race, gender, and ocular structure in patients with and without primary open angle glaucoma (POAG). METHODS: AH samples were collected from 231 patients undergoing phacoemulsification or glaucoma incisional surgery at the Medical College of Georgia, Augusta University and subsequently analyzed via LC-MS/MS. The number of peptide spectrum matches (PSMs) for each protein was used as a semi-quantitative measure of relative protein levels. Parameters related to ocular structure were determined using Optical Coherence Tomography (OCT) and Heidelberg Retinal Tomography (HRT). These data sets were probed for relationships between apolipoprotein levels and POAG, demographics (gender and race), and ocular structure. RESULTS: A total of ten apolipoproteins were detected in the 231 collected AH samples, with six detected in 100% of the samples, one detected in almost 57% of the samples and three detected in less than 10% of the samples. The levels of APOA1, APOC3, and APOD were higher among POAG subjects. Stratification by gender and race revealed demographic-specific variations. The levels of five apolipoproteins (APOA1, APOA2, APOA4, APOC3, and APOD) were higher in female POAG patients, whereas no apolipoprotein levels were altered in male POAG patients. The levels of APOA1, APOA2, APOA4, and APOD were increased in glaucomatous African American patients, whereas APOE and APOH levels were decreased in glaucomatous Caucasian patients. We also found distinct associations between apolipoprotein levels and OCT and HRT parameters in patients with and without POAG. CONCLUSIONS: The intra-population variation in apolipoprotein levels highlights the heterogeneity of glaucoma as a disease, suggesting the importance of personalized treatments. Gender and race-specific alterations may be associated with higher risks of POAG in females and members of the African American population.

Survey of Microinvasive Glaucoma Surgery and Other Glaucoma Surgical Experience among United States Ophthalmology Residency Programs.

Purpose The aim of the study is to assess the state of glaucoma surgical training in United States ophthalmology residency programs, including experience with microinvasive glaucoma surgery (MIGS). Design The design of the study is anonymous, internet-based national survey. Participants Current United States ophthalmology residents of residency programs accredited by the Accreditation Council for Graduate Medical Education (ACGME). Methods An anonymous survey link was emailed to all 120 accredited United States ophthalmology residency programs inviting residents to participate in an assessment of residency glaucoma surgical experience. Survey responses were collected between January 21, 2019 and March 4, 2019 and analyzed using descriptive statistics. Main Outcome Measures The main outcomes of the study are demographic information, practice intentions, and anticipated primary surgical experience with ACGME-required glaucoma procedures and MIGS procedures, as self-reported by U.S. ophthalmology residents. Results Of the estimated 1,479 U.S. ophthalmology residents, 161 residents participated (10.9%). A total of 118 residents (73.2%) reported any degree of anticipated MIGS primary surgical experience during residency, with the iStent being the most familiar technique. The likelihood of any anticipated MIGS experience during residency was not significantly different by geographic region ( p = 0.16), however, anticipated volume varied significantly ( p = 0.037). Of the 113 respondents who reported an intention to manage glaucoma surgically in their eventual practice, 25 (22.1%) reported no anticipated primary MIGS experience during residency. 73.3% of residents anticipating MIGS experience anticipated 0 to 10 cases, with 42.9% anticipating less than 5 cases as primary surgeon. Conclusion MIGs are not a required component of the glaucoma surgical curriculum for U.S. ophthalmology residents. Although the majority of ophthalmology residents surveyed intend to manage glaucoma surgically in eventual practice, most receive minimal experience with these novel techniques during residency. Surgical training is variable by geographic region.

The Constitutive Proteome of Human Aqueous Humor and Race Specific Alterations.

Aqueous humor (AH) is the fluid in the anterior and posterior chambers of the eye that contains proteins regulating ocular homeostasis. Analysis of aqueous humor proteome is challenging, mainly due to low sample volume and protein concentration. In this study, by utilizing state of the art technology, we performed Liquid-Chromatography Mass spectrometry (LC-MS/MS) analysis of 88 aqueous humor samples from subjects undergoing cataract surgery. A total of 2263 unique proteins were identified, which were sub-divided into four categories that were based on their detection in the number of samples: High (n = 152), Medium (n = 91), Low (n = 128), and Rare (n = 1892). A total of 243 proteins detected in at least 50% of the samples were considered as the constitutive proteome of human aqueous humor. The biological processes and pathways enriched in the AH proteins mainly include vesicle mediated transport, acute phase response signaling, LXR/RXR activation, complement system, and secretion. The enriched molecular functions are endopeptidase activity, and various binding functions, such as protein binding, lipid binding, and ion binding. Additionally, this study provides a novel insight into race specific differences in the AH proteome. A total of six proteins were upregulated, and five proteins were downregulated in African American subjects as compared to Caucasians.

Epibulbar Plasmacytoma Masquerading as Subconjunctival Hemorrhage in a Patient With Multiple Myeloma.

PURPOSE: We report a 75-year-old woman with a history of multiple myeloma immunoglobulin D (IgD) variant, who presented with an epibulbar plasmacytoma masquerading as a subconjunctival hemorrhage. METHODS: Magnetic resonance imaging of the brain and orbits with and without contrast was obtained and surgical biopsy of the subconjunctival lesion was performed; histopathology confirmed the diagnosis of plasmacytoma. RESULTS: Subconjunctival biopsy revealed a plasma cell neoplasm infiltrate in the episcleral layer. The subconjunctival biopsy stained positive for CD138 and lambda-immunohistochemistry in the majority of plasma cells. Histologic findings were consistent with involvement by known IgD plasma cell myeloma where previous bone marrow biopsy demonstrated myeloma cells which stained monoclonally for IgD-lambda light chains. CONCLUSIONS: Although plasma cell neoplasms seldom present with ocular manifestations, it is crucial to recognize that these tumors may be associated with multiple myeloma. In patients with known multiple myeloma who present with subconjunctival hemorrhage, close follow-up is highly recommended, as this may be the initial presentation of an ocular plasmacytoma. Although a plasmacytoma is a rare subconjunctival lesion, it should not be immediately excluded from the differential diagnosis of such lesions.