Glaucoma is the leading cause of irreversible blindness worldwide, with its primary risk factor arising from elevated intraocular pressure (IOP) due to an imbalance between aqueous humor production and outflow. This study aims to establish quantitative correlations among IOP, iris mechanical properties, channel microstructures, and aqueous humor dynamics through three-dimensional modeling and finite element analysis, overcoming the limitations of conventional experimental techniques in studying aqueous flow within the trabecular meshwork (TM) outflow pathway. A three-dimensional fluid-structure interaction (FSI) model incorporating the layered TM structure, Schlemm's canal (SC), iris, and other anterior segment tissues was developed based on human ocular anatomy. FSI simulations were performed to quantify the effects of IOP variations and iris Young's modulus on tissue morphology and aqueous humor dynamics parameters. The computational results demonstrated that axial iris deformation showed significant correlations with IOP and iris Young's modulus. Although elevated IOP exhibited minimal effects on hydrodynamic parameters in the anterior and posterior chambers, it markedly suppressed aqueous flow velocity in the TM region. Additionally, wall shear stress in SC and collector channels displayed high sensitivity to IOP variations. These findings reveal that the tissue mechanics-FSI mechanism modulates outflow resistance by regulating aqueous humor dynamics, offering valuable references for developing clinical therapies targeting IOP reduction in glaucoma management.
Humans ; Trabecular Meshwork/anatomy & histology* ; Finite Element Analysis ; Aqueous Humor/metabolism* ; Intraocular Pressure/physiology* ; Glaucoma/physiopathology* ; Iris/anatomy & histology* ; Computer Simulation ; Models, Biological

BACKGROUNDManganese-enhanced magnetic resonance imaging (MEMRI) for visual pathway imaging via topical administration requires further research. This study investigated the permeability of the corneal epithelium and corneal toxicity after topical administration of Mn2+ to understand the applicability of MEMRI.

METHODSForty New Zealand rabbits were divided into 0.05 mol/L, 0.10 mol/L, and 0.20 mol/L groups as well as a control group (n = 10 in each group). Each group was further subdivided into epithelium-removed and epithelium-intact subgroups (n = 5 in each subgroup). Rabbits were given 8 drops of MnCl2in 5 min intervals. The Mn2+ concentrations in the aqueous and vitreous humors were analyzed using inductively coupled plasma-mass spectrometry at different time points. MEMRI scanning was carried out to image the visual pathway after 24 h. The corneal toxicity of Mn2+ was evaluated with corneal imaging and pathology slices.

RESULTSBetween the aqueous and vitreous humors, there was a 10 h lag for the peak Mn2+ concentration times. The intraocular Mn2+ concentration increased with the concentration gradients of Mn2+ and was higher in the epithelium-removed subgroup than that in the epithelium-intact subgroup. The enhancement of the visual pathway was achieved in the 0.10 mol/L and 0.20 mol/L epithelium-removed subgroups. The corresponding peak concentrations of Mn2+ were 5087 ± 666 ng/ml, 22920 ± 1188 ng/ml in the aqueous humor and 884 ± 78 ng/ml, 2556 ± 492 ng/ml in the vitreous body, respectively. Corneal injury was evident in the epithelium-removed and 0.20 mol/L epithelium-intact subgroups.

CONCLUSIONSThe corneal epithelium is a barrier to Mn2+, and the iris and lens septum might be another intraocular barrier to the permeation of Mn2+. An elevated Mn2+ concentration contributes to the increased permeation of Mn2+, higher MEMRI signal, and corneal toxicity. The enhancement of the visual pathway requires an effective Mn2+ concentration in the vitreous body.

Administration, Topical ; Animals ; Aqueous Humor ; drug effects ; metabolism ; Cornea ; drug effects ; metabolism ; Epithelium, Corneal ; drug effects ; metabolism ; Magnetic Resonance Imaging ; methods ; Male ; Manganese ; administration & dosage ; pharmacokinetics ; pharmacology ; Rabbits ; Visual Pathways ; drug effects ; Vitreous Body ; drug effects ; metabolism

PURPOSE: To compare oxidative stress status in the aqueous humor of highly myopic eyes and control eyes. METHODS: Aqueous humor samples were collected from 15 highly myopic eyes (high myopia group) and 23 cataractous eyes (control group) during cataract surgery. Central corneal thickness, corneal endothelial cell density, hexagonality of corneal endothelial cells, and cell area of corneal endothelial cells were measured using specular microscopy. Axial length was measured using ultrasound biometry. 8-Hydroxydeoxyguanosine (8-OHdG) and malondialdehyde levels were measured using enzyme-linked immunosorbent assay. RESULTS: 8-OHdG level was lower in the aqueous humor of myopic patients than in that of control group (p = 0.014) and was positively correlated with central corneal thickness and negatively correlated with axial length (r = 0.511, p = 0.02; r = -0.382, p < 0.001). There was no correlation between 8-OHdG level and corneal endothelial cell density, hexagonality, or cell area. Malondialdehyde level did not show any correlation with any parameters evaluated. CONCLUSIONS: 8-OHdG might be a sensitive biomarker for evaluating oxidative stress status in the eye. Oxidative stress level was lower in the aqueous humor of highly myopic eyes compared to that in control eyes, which indicates lower metabolic activity in these eyes.
Aged ; Aqueous Humor/*metabolism ; Deoxyguanosine/*analogs & derivatives/metabolism ; Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Male ; Malondialdehyde/*metabolism ; Middle Aged ; Myopia/*metabolism/physiopathology ; *Oxidative Stress ; Refraction, Ocular/*physiology ; Severity of Illness Index

OBJECTIVETo isolate exosomes from rabbit aqueous humor and to investigate their immunosuppression function.

METHODSAqueous humor was collected from 40 New Zealand rabbits and exosomes were isolated by fractional separation and ultracentrifugation methods; the morphology was studied with electron microscopy. The immunosuppressive-related proteins of exosomes were detected with Western blotting; their inhibitory effect on ConA-induced proliferation of T lymphocyte was estimation with CCK-8 cells proliferation assay.

RESULTSEight milliliters of aqueous humor were collected from 40 New Zealand rabbits and 200 μg exosomes was yielded. Under electron microscope, the exosomes had typical structure of lipid bi-layer with a diameter of 50-100 nm. The results of Western blotting showed that these exosomes expressed Hsp70, CD9 and Alix but not Grp94, presenting a typical exosomes protein profile. Moreover, exosomes expressed high level of TGF-β and significantly inhibited the proliferation of T lymphocytes.

CONCLUSIONImmunosuppressive exosomes can be isolated from rabbit aqueous humor, which may be involved in immunotolerance of the eye.

Animals ; Aqueous Humor ; immunology ; Cells, Cultured ; Exosomes ; immunology ; metabolism ; ultrastructure ; Female ; Immune Tolerance ; Male ; Rabbits ; T-Lymphocytes ; immunology

OBJECTIVETo establish a RP-HPLC method for determination of the content of ginsenoside Rg1 in the rabbits aqueous humor, blood and ocular tissues, which were given intragastric administration with the co-xueshuantong soft capsules. The drug concentration in rabbits at different times after oral administration has been determined and the pharmacokinetics characteristics has been researched.

METHODThe compound xueshuantong soft capsules were administrated to the healthy New Zealand rabbits by gavage (10 mg x kg(-1) per rabbit). The concentration of Ginseng Rg1 in aqueous humor, blood and ocular tissues at different time was determined by RP-HPLC.

RESULTRP-HPLC can be established for the determination of ginsenoside Rg1 in the rabbits aqueous humor, blood, ocular tissue. The calibration of curves was linear within the range of 7.60-152.0 mg x L(-1) (r = 0.999 6) for ginsenoside Rg1 in aqueous humor and the calibration of curves were linear within the range of 10.35-103, 50 mg x L(-1) (r = 0.999 8) for ginsenoside Rg1 in blood. Determination of the recovery rate to meet the requirements.

CONCLUSIONThe ginsenosides Rg1 could transmit the blood-ocular barrier into the eyes and reach a certain concentration. The research provides a theoretical and experimental basis for the systemic administration of compound Xueshuantong to treat eye diseases.

Animals ; Aqueous Humor ; metabolism ; Calibration ; Capsules ; Chromatography, High Pressure Liquid ; Drugs, Chinese Herbal ; pharmacokinetics ; Female ; Ginsenosides ; pharmacokinetics ; Male ; Rabbits

PURPOSE: To investigate serial changes in photoreceptor status and associated visual outcome in patients with persistent submacular fluid after successful scleral buckle surgery for macula-off rhegmatogenous retinal detachment. METHODS: This was a prospective observational case series including 76 consecutive patients who underwent successful scleral buckle surgery for macula-off rhegmatogenous retinal detachment with symptom duration < or =90 days at a single tertiary hospital. Optical coherence tomography (OCT) and visual acuity examination were performed at one month and three months postoperatively and at three-month intervals until the submacular fluid disappeared. Main outcome measures were postoperative photoreceptor status on OCT and visual acuity. RESULTS: Forty-two patients (55.3%) showed persistent submacular fluid at postoperative one month. Of 42 patients with persistent submacular fluid, three (7.1%) showed photoreceptor disruption on OCT. None of the 34 patients without persistent submacular fluid showed photoreceptor disruption. Two patients (4.8%) had progressive photoreceptor disruption, and one patient (2.4%) had early photoreceptor disruption. All three patients showed photoreceptor reappearance and limited visual restoration after absorption of submacular fluid. Final visual acuities were significantly worse in these three patients (20 / 1000, 20 / 133, and 20 / 133) compared to those of the other patients (mean, 20 / 30) with persistent submacular fluid and intact photoreceptors. CONCLUSIONS: Even after successful scleral buckle surgery for rhegmatogenous retinal detachment, photoreceptor disruption can occur related to persistent submacular fluid and may be a cause of poor visual outcome.
Adolescent ; Adult ; Aged ; Aged, 80 and over ; Aqueous Humor/*metabolism ; Child ; Female ; Follow-Up Studies ; Humans ; Male ; Middle Aged ; Photoreceptor Cells/*pathology ; *Postoperative Complications ; Prospective Studies ; Retinal Detachment/*surgery ; *Scleral Buckling ; Tomography, Optical Coherence ; Visual Acuity/physiology ; Young Adult

We report a case of posterior scleritis effectively managed with intravitreal bevacizumab. A 71-year-old woman was diagnosed with posterior scleritis. Although she was initially treated with systemic steroids, her clinical presentation deteriorated. She was then treated with a single intravitreal injection of bevacizumab and aqueous humor collection. The aqueous level of vascular endothelial growth factor prior to the intravitreal injection was 880.51 pg/mL, greater than that in the healthy control group (p < 0.001). One month later, the scleritis was completely resolved, and the patient remained stable during six months of follow-up. Intravitreal bevacizumab appears to be an effective adjuvant therapy for patients with posterior scleritis.
Aged ; Angiogenesis Inhibitors/administration & dosage ; Antibodies, Monoclonal, Humanized/*administration & dosage ; Aqueous Humor/metabolism ; Diagnosis, Differential ; Female ; Fluorescein Angiography ; Follow-Up Studies ; Fundus Oculi ; Humans ; Interleukin-8/metabolism ; Intravitreal Injections ; Microscopy, Acoustic ; Scleritis/*drug therapy/metabolism/pathology ; Vascular Endothelial Growth Factor A/metabolism

Primary and secondary corneal endothelial decompensation leads to stromal edema, corneal opacity and loss of visual acuity. The pathogenesis of corneal endothelial decompensation is that adult corneal endothelium in vivo lacks of a robust proliferative response to injury, does not divide sufficiently to replace the lost cells. Previous studies indicate that cell-cell contact inhibition and transforming growth factor-beta2 (TGF-β2) in aqueous humor may be responsible for maintaining human endothelial cells in a non-replicative state in vivo. The results of the experimental investigation by using immunofluorescent staining of the cell cycle-associated proteins and cell proliferation marker Ki67 in corneal endothelium indicate that human corneal endothelial cells in vivo are arrested in the G1-phase and have not exited from the cell cycle. Successful outgrowth in culture of human corneal endothelial cells in vitro and the establishment of the immortalized human endothelial cell line, provide strong evidence that corneal endothelial cells retain proliferative capacity. Experiments with cell culture ex vivo demonstrate that corneal endothelial cells cultured from young donors grow more robustly than those from older donors, and cells cultured from peripheral area of corneas show greater cell density than central regions. Studies have demonstrated that in vitro human corneal endothelia undergo mitotic changes in response to stimulation of growth promoting agents, such as growth factors, EDTA and extracellular matrix. Identification of corneal endothelial stem cells and isolation and culture of human endothelial precursor cells in vitro will be beneficial for further investigation regarding the mechanism of corneal endothelial regeneration as well as corneal endothelial cells in vitro culture.
Aqueous Humor ; metabolism ; Cell Count ; Cell Culture Techniques ; Cell Cycle ; Cell Proliferation ; Cells, Cultured ; Contact Inhibition ; Endothelium, Corneal ; cytology ; Humans ; Stem Cells ; Transforming Growth Factor beta2 ; metabolism

The aim of the study is to prepare flurbiprofen axetil nanoemulsion-in situ gel system (FBA/NE-ISG) and observe its ocular pharmacokinetics, rheological behavior, TEM images, irritation and cornea retention. Production of nanoemulsion was based on high-speed shear and homogenization process, and then mixed with gellan gum to prepare FBA/NE-ISG. Rheological study showed that FBA/NE-ISG possesses strong gelation capacity and its viscosity and elastic modulus increases by 2 Pa*s and 5 Pa respectively when mixed with artificial tear at the ratio of 40 : 7. TEM images suggested no significant changes in particle morphology of the pre and post gelation. Good ocular compatibility of FBA/NE-ISG was testified by the irritation test based on histological examination. In vivo fluorescence imaging system was applied to investigate the characteristics of cornea retention, and the results indicated that the nanoemulsion-in situ gel (NE-ISG) prolonged the cornea retention time significantly since K(NE-ISG) (0.008 5 min(-1) was much lower compared with flurbiprofen sodium eye drops (FB-Na, 0.03% w/v) of which the K(Eye drops) was 0.105 2 min(-1), indicated that the cornea retention time of NE-ISG was prolonged significantly. Pharmacokinetics of FBA/NE-ISG in rabbit aqueous humor was studied by cornea puncture, the MRT (12.3 h) and AUC(0-12h) (126.8 microg x min x mL(-1)) of FBA/NE-ISG was 2.7 and 2.9 times higher than that of the flurbiprofen sodium eye drops respectively, which meant that the ocular bioavailability was improved greatly by the novel preparation. Therefore, FBA/NE-ISG can enhance the ocular bioavailability by prolonging drug corneal retention significantly. What's more, encapsulated by emulsion droplets prodrug flurbiprofen (FBA) instead of flurbiprofen (FB) can reduce the ocular irritation.
Animals ; Anti-Inflammatory Agents, Non-Steroidal ; administration & dosage ; adverse effects ; pharmacokinetics ; Aqueous Humor ; metabolism ; Biological Availability ; Cornea ; cytology ; drug effects ; Emulsions ; Female ; Flurbiprofen ; administration & dosage ; adverse effects ; analogs & derivatives ; pharmacokinetics ; Gels ; Male ; Nanoparticles ; Ophthalmic Solutions ; Rabbits ; Rheology ; Viscosity

BACKGROUNDOphthalmic gel has been developed to increase the drug concentration in aqueous humor and to retard the loss of drug from the conjunctival sac. The research was to compare the drug concentration in aqueous humor of cataract patients administered 0.3% gatifloxacin ophthalmic gel with that in patients administered 0.3% gatifloxacin ophthalmic solution.

METHODSNinety-six patients with cataract (96 eyes) were randomly assigned to 8 groups. The patients in groups 1-4 received topical gatifloxacin 0.3% ophthalmic gel and those in groups 5-8 received gatifloxacin 0.3% ophthalmic solution. The dose regimen was 1 drop, 4 times a day for 3 consecutive days prior to cataract surgery. On the day of surgery, 1 drop was applied at 15, 30, 60 or 120 minutes before commencement of cataract surgery in groups 1 and 5, groups 2 and 6, groups 3 and 7, and groups 4 and 8, respectively. Aqueous humor was extracted during the cataract surgery for the analysis of gatifloxacin concentration..

RESULTSThe concentrations of gatifloxacin in aqueous humor were (0.24 +/- 0.25) microg/ml, (1.11 +/- 0.74) microg/ml, (2.32 +/- 2.01) microg/ml and (1.85 +/- 1.14) microg/ml in groups 1 to 4, and (0.16 +/- 0.25) microg/ml, (0.31 +/- 0.24) microg/ml, (0.75 +/- 0.28) microg/ml and (0.33 +/- 0.22) microg/ml in groups 5 to 8, respectively. Patients receiving gatifloxacin ophthalmic gel showed greater mean values of gatifloxacin concentration in aqueous humor than those receiving gatifloxacin solution, and such differences were significant with P < 0.05 for all comparisons except that between groups 1 and 5.

CONCLUSIONTopical gatifloxacin ophthalmic gel can attain significantly greater drug concentrations in human aqueous humor than gatifloxacin ophthalmic solution.

Aged ; Aged, 80 and over ; Anti-Infective Agents ; administration & dosage ; analysis ; pharmacokinetics ; therapeutic use ; Aqueous Humor ; metabolism ; Cataract ; drug therapy ; metabolism ; Chromatography, High Pressure Liquid ; Female ; Fluoroquinolones ; administration & dosage ; analysis ; pharmacokinetics ; therapeutic use ; Humans ; Male ; Middle Aged ; Tandem Mass Spectrometry