Bleb-Independent Glaucoma Surgery to Activate the Uveolymphatic Route of Non-Trabecular Aqueous Humor Outflow: Short-Term Clinical and OCT Results

The deep sclerectomy technique was modified to enhance aqueous humor (AH) outflow via the non-trabecular pathway. A pilot study was carried out to assess its safety and effectiveness. Thirty-eight patients were under observation. After superficial scleral flap (4 × 4 mm), deep scleral layers were divided into three parts by three parallel-to-limbus incisions. Deep sclerectomy without creating a window in the Descemetes’ membrane was carried out in the distal part. A collagen implant was placed under the sclera of the remaining two parts with one end in the intrascleral pool. The third proximal part was excised to expose the uvea and implant. A Nd:YAG laser trabeculotomy at the surgery site was made on postoperative days 7–10. Outcome measures were IOP change, use of hypotensive medication(s), complications, and the need for a second surgery. At six months, the mean IOP decreased from 29.1 ± 9.2 mm Hg to 14.0 ± 4.3 mm Hg (p = 1.4 × 10−9); hypotensive medication use reduced from 2.9 ± 0.9 to 0.6 ± 1.0 (p = 1.3 × 10−10); complete success was achieved in 68.4% of cases and partial success was achieved in 31.6% of cases. Intraoperative and postoperative complications were rare and manageable. The OCT of the surgery site revealed the absence of bleb in all cases. Lymphatic vessels with characteristic bicuspid valves in their lumen were detected in conjunctiva near the operation site and over it in 32 patients. IOP decrease in the proposed technique was achieved by activation of the uveolymphatic route of AH outflow.

Usefulness of Liquid Biopsy for Intraocular Malignancies

Retinoblastoma (RB) is the most common primary intraocular malignancy in children, whereas Uveal melanoma (UM) is the most common intraocular malignancy in adults [1,2]. Tissue biopsy is the standard gold technique for diagnosing the malignant neoplasm but an incisional tissue biopsy or fine needle aspiration biopsy (FNAB) is contraindicated for the intraocular malignancy [3]. Clinical diagnosis and imaging study are the only way to diagnose the intraocular malignancy due to the risk and fear of extraocular spread [4]. Recently, liquid biopsy has gained in popularity in the ophthalmic field. Liquid biopsy allows retinoblastoma diagnosis and a better understanding of the metastatic spread of uveal melanoma. Recently, the USA Food and Drug Administration (FDA) approved the make use of liquid biopsy (LB) as an appropriate diagnosis, prognosis, and also for monitoring tool in non-small cell lung carcinoma to keep away from invasive tissue biopsy in designated cases [5-7]. Liquid biopsy (LB) utilizes biofluid to evaluate for tumor-derived cells or cell-free DNA. LB is a relatively non-invasive technique rather than a tissue biopsy. In LB, material collected from multiple body fluids such as aqueous humor (AH), blood, cerebrospinal fluid, urine, and saliva for molecular diagnosis [8] and detecting of cancer biomarkers such as circulating tumor cells (CTC), tumor derived cell free DNA (ct-DNA), circulating tumor RNA (ct-RNA), microRNA (miRNA), tumorrelated exosomes (TREs), and extracellular vescicles (EVs) [7]. Aqueous humor samples for RB (Ocular LB) and Venous blood samples for UM (systemic LB) are utilizing for analyzing the molecular characteristics [8]. In others ophthalmic malignancies like conjunctival melanoma or squamous cell carcinoma, the role of LB is still not studied because tissue biopsy is routinely done for confirming the diagnosis and also for mutational status [9-11].

Features of the level of matrix metalloproteinase-2, -3, -9 and tissue inhibitors of metalloproteinases-1, -2, -3, -4 in the aqueous humor of patients with primary open-angle glaucoma

Aim. To study the content of matrix metalloproteinase (MMP)-2, -3, -9 and tissue inhibitors of metalloproteinases (TIMPs) -1, -2, -3, -4 in the aqueous humor of patients with moderate primary open-angle glaucoma (POAG).Materials and methods. The experimental group included 47 patients with verified moderate primary open-angle glaucoma. The control group consisted of 26 patients with uncomplicated cataract. The levels of MMP-2, -3, -9 were determined with Luminex Performance Human MMP Magnetic Panel 3-plex kit (R&D Systems, USA), the concentration of TIMPs-1, -2, -3, - 4 was determined with the Human TIMP Magnetic Luminex Performance Assay 4-plex kit (R&D Systems, USA). The study was carried out using flow-through field fluorometry on a Bio-Plex 200 double-beam laser analyzer (Bio-Rad, USA).Results. The study showed a statistically significant increase in the levels of matrix metalloproteinase-2 and tissue inhibitors of matrix metalloproteinases-1, -2, -3, -4 in the aqueous humor of patients with moderate POAG compared with patients with uncomplicated cataract.Conclusion. The obtained data on high concentrations and imbalance in the levels of matrix metalloproteinases and their tissue inhibitors in the aqueous humor of patients with moderate POAG confirm the role of local inflammation, as well as impairments in the structure of the extracellular matrix and its remodeling in the mechanisms of development of this pathology.

Evaluation of matrix metalloproteinases and tissue inhibitors of metalloproteinases in aqueous humor of dogs with versus without naturally occurring primary angle-closure glaucoma

OBJECTIVE To compare concentrations of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in aqueous humor from ophthalmologically normal dogs and dogs with naturally occurring primary angle-closure glaucoma (cPACG). SAMPLE Aqueous humor samples from 12 eyes with cPACG and 18 ophthalmologically normal eyes of dogs. PROCEDURES A multiplex fluorescence-based ELISA was used to measure concentrations of MMP-1, MMP-2, MMP-3, MMP-8, MMP-9, MMP-10, MMP-13, TIMP-1, TIMP-2, and TIMP-4. Results for eyes with versus without cPACG were compared. RESULTS Significantly higher mean concentrations of MMP-1 (45% higher), MMP-2 (55% higher), MMP-3 (39% higher), MMP-8 (79% higher), MMP-9 (29% higher), MMP-10 (60% higher), TIMP-1 (63% higher), and TIMP-2 (136% higher) were detected in aqueous humor from eyes with cPACG, compared with ophthalmologically normal eyes. CLINICAL RELEVANCE MMPs and TIMPs have pivotal roles in extracellular matrix turnover and homeostasis in the outflow pathways of the eye. Results of the present study documented higher concentrations of MMPs and TIMPs in aqueous humor samples from dog eyes with late-stage cPACG. Although, to our knowledge, TIMPs have not previously been evaluated in the context of cPACG, the markedly higher concentration of TIMPs in eyes with cPACG suggested that inhibition of proteolysis and extracellular matrix turnover might be a factor in the development of glaucoma in susceptible individuals. However, because the present study used samples from dogs with late-stage cPACG, further work is required to characterize the temporal relationship between MMP and TIMP concentration changes and onset or progression of disease.

Metabolite Changes in the Aqueous Humor of Patients With Retinal Vein Occlusion Macular Edema: A Metabolomics Analysis

Macular edema (ME) is the main cause of visual impairment in patients with retinal vein occlusion (RVO). The degree of ME affects the prognosis of RVO patients, while it lacks objective laboratory biomarkers. We aimed to compare aqueous humor samples from 28 patients with retinal vein occlusion macular edema (RVO-ME) to 27 age- and sex-matched controls by ultra-high-performance liquid chromatography equipped with quadrupole time-of-flight mass spectrometry, so as to identify the key biomarkers and to increase the understanding of the mechanism of RVO-ME at the molecular level. Through univariate and multivariate statistical analyses, we identified 60 metabolites between RVO-ME patients and controls and 40 differential metabolites in mild RVO-ME [300 μm ≤ central retinal thickness (CRT) < 400 μm] patients compared with severe RVO-ME (CRT ≥ 400 μm). Pathway enrichment analysis showed that valine, leucine, and isoleucine biosynthesis; ascorbate and aldarate metabolism; and pantothenate and coenzyme A biosynthesis were significantly altered in RVO-ME in comparison with controls. Compared with mild RVO-ME, degradation and biosynthesis of valine, leucine, and isoleucine; histidine metabolism; beta-alanine metabolism; and pantothenate and coenzyme A biosynthesis were significantly changed in severe RVO-ME. Furthermore, the receiver operating characteristic (ROC) curve analysis revealed that adenosine, threonic acid, pyruvic acid, and pyro-L-glutaminyl-l-glutamine could differentiate RVO-ME from controls with an area under the curve (AUC) of >0.813. Urocanic acid, diethanolamine, 8-butanoylneosolaniol, niacinamide, paraldehyde, phytosphingosine, 4-aminobutyraldehyde, dihydrolipoate, and 1-(beta-D-ribofuranosyl)-1,4-dihydronicotinamide had an AUC of >0.848 for distinguishing mild RVO-ME from severe RVO-ME. Our study expanded the understanding of metabolomic changes in RVO-ME, which could help us to have a good understanding of the pathogenesis of RVO-ME.

Decorin Concentrations in Aqueous Humor of Patients with Diabetic Retinopathy

Diabetic retinopathy (DR) is a microvascular complication of diabetes in the retina. Chronic hyperglycemia damages retinal microvasculature embedded into the extracellular matrix (ECM), causing fluid leakage and ischemic retinal neovascularization. Current treatment strategies include intravitreal anti-vascular endothelial growth factor (VEGF) or steroidal injections, laser photocoagulation, or vitrectomy in severe cases. However, treatment may require multiple modalities or repeat treatments due to variable response. Though DR management has achieved great success, improved, long-lasting, and predictable treatments are needed, including new biomarkers and therapeutic approaches. Small-leucine rich proteoglycans, such as decorin, constitute an integral component of retinal endothelial ECM. Therefore, any damage to microvasculature can trigger its antifibrotic and antiangiogenic response against retinal vascular pathologies, including DR. We conducted a cross-sectional study to examine the association between aqueous humor (AH) decorin levels, if any, and severity of DR. A total of 82 subjects (26 control, 56 DR) were recruited. AH was collected and decorin concentrations were measured using an enzyme-linked immunosorbent assay (ELISA). Decorin was significantly increased in the AH of DR subjects compared to controls (p = 0.0034). AH decorin levels were increased in severe DR groups in ETDRS and Gloucestershire classifications. Decorin concentrations also displayed a significant association with visual acuity (LogMAR) measurements. In conclusion, aqueous humor decorin concentrations were found elevated in DR subjects, possibly due to a compensatory response to the retinal microvascular changes during hyperglycemia.

Wild Rabbit Exposure to Leishmania infantum, Toxoplasma gondii, Anaplasma phagocytophilum and Babesia caballi Evidenced by Serum and Aqueous Humor Antibody Detection

Wild rabbits (Oryctolagus cuniculus) can be important sentinel species for the presence of zoonotic pathogens. Therefore, we collected blood samples from wild rabbits harvested by hunters during the hunting season 2019–2020 on the island of Lemnos, to determine exposure of wild rabbits to the zoonotic pathogens Leishmania infantum, Toxoplasma gondii, Anaplasma phagocytophilum and Babesia caballi, as well as aqueous humor to assess its diagnostic performance in terms of sensitivity, specificity, positive and negative likelihood ratios. Antibodies against these pathogens were detected by Indirect Immunofluorescence Antibody (IFA) assay. Out of the 72 wild rabbits included in the study, 4.2%, 5.5%, 18% and 9.7% were seropositive to L. infantum, T. gondii, A. phagocytophilum and B. caballi, respectively. Although less frequently, antibodies were also detected in aqueous humor of wild rabbits. The antibody detection in aqueous humor presented 100% specificity but decreased sensitivity compared to serum suggesting that aqueous humor could be successfully used in epidemiological studies to confirm exposure at the population level but has little diagnostic value at the individual level. This is the first report on the seropositivity of wild rabbits to A. phagocytophilum and B. caballi and the detection of antibodies against A. phagocytopylum, L. infantum, T. gondii and B. caballi in the aqueous humor.