Experimental eye research最新文献

This study aimed to establish a modified calculation formula for the grading of meibomian glands. Meibography images from 102 participants by different examiners on separate machines on two consecutive days were analyzed, quantified and compared side-by-side. Measure and calculate the ratio of the MGs area to the whole eyelid area and the ratio of the MGs to the corneal base area. Our findings demonstrate that there were significant differences in the ratio of the meibomian gland area to the whole eyelid area between two measurements, but not in the ratio of the meibomian gland area to the corneal base area. The measurement of the eyelid area showed bigger variations and poorer repeatability than the meibomian gland area and the corneal base area. As such, the ratio of the meibomian gland area to the corneal base area is a more stable indicator for the grading of meibomian glands over multiple measurement.

Aim: Previous studies have demonstrated that contact lenses coated with the antimicrobial cationic peptide Mel4, a derivative of melimine, can reduce the occurrence of keratitis. However, the antimicrobial activity of Mel4 weakened over time due to its susceptibility to proteolytic degradation. Oligo-N-substituted glycine peptoids such as TM5 and TM18 possess antimicrobial properties and are resistant to proteolytic breakdown. This study focused on exploring methods for covalently attaching these peptoids to contact lenses to enhance their durability and performance in vitro.

Methods: The peptoids TM5 and TM18 were covalently attached to etafilcon lenses via carbodiimide chemistry (EDC/NHS), oxazoline plasma, and plasma ion immersion implantation (PIII). The lenses were analyzed using X-ray photoelectron spectroscopy (XPS), surface charge, and hydrophobicity. Inhibition of adhesion of multidrug-resistant Pseudomonas aeruginosa and cytotoxicity on corneal epithelial cells were evaluated. The impact of moist heat sterilization on activity was also assessed.

Results: XPS confirmed peptoid binding to lenses. Peptoid coatings slightly increased contact angles (≤23°) without affecting overall charge. Peptoids, bound via carbodiimide, inhibited P. aeruginosa adhesion by over 5 log10 CFU per lens, outperforming melimine, which required six times the concentration for a 3 log10 reduction. Peptoids attached via oxazoline or PIII reduced adhesion by >5 log10 CFU. All covalent methods significantly reduced bacterial adhesion compared to untreated lenses (P < 0.0001). Peptoid-bound lenses were non-toxic to corneal epithelial cells. Sterilization did not affect carbodiimide-treated lenses but reduced the activity of oxazoline and PIII surfaces by 1-2 log10 CFU.

Conclusion: Peptoids TM5 and TM18 effectively reduced P. aeruginosa adhesion on lenses, with carbodiimide-bound surfaces retaining activity post-sterilization, showing promise for the development of antimicrobial contact lenses.

Purpose: Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly. To date, there are no effective therapies to counteract AMD towards the most severe stages characterised by a progressive loss of photoreceptors triggered by retinal pigmented epithelium dysfunction. Given their easy source and their high proliferative potential, Dental Pulp Stem Cells (DPSCs) are considered promising for regenerative medicine. The main advantage of DPSCs is related to their paracrine immunosuppressive and immunoregulatory abilities, including the capability to promote regeneration of damaged tissues. Recent studies demonstrated the therapeutic potential of DPSCs-conditioned media (CM) in neurodegenerative diseases. In addition, we have already shown a differential expression of some growth factors and cytokines in CM derived from DPSCs cultured in hypoxia and normoxia conditions.

Aim: In this study we evaluated the capability of DPSCs-CM to counteract retinal degeneration in an animal model of AMD. DPSCs-CM were intravitreally injected the day before the exposure of albino rats to high intensity light (LD).

Results: We evaluated the retinal function, and we performed morphological and molecular analysis a week after the LD, in accordance with the well-established protocol of our light damage model. DPSCs-CM obtained from hypoxia (HYPO-CM) or normoxia (NORM-CM), were able to preserve the retinal function, to reduce the damaged area and to counteract the upregulation of key factors involved in retinal degeneration, like FGF-2. Furthermore, we demonstrated that neither conditioned media modified inflammatory activation, as shown by both microglia activation and GFAP upregulation, but in vitro studies demonstrated a significant effect of both CM to counteract oxidative stress, one of the main causes of AMD.

Conclusion: Taken together, our study demonstrated that NORM-CM and HYPO-CM, albeit with a different chemical composition, could represent eligible candidates to counteract retinal degeneration in an animal model of AMD. Further studies are needed to obtain conditioned media with the best performance in term of retinal protection.

Proliferative vitreoretinopathy (PVR) is a multifactorial ocular condition characterized by the development of fibrotic membranes inside the vitreous cavity and on the detached retina, which can result in severe blindness. Semaphorin7A (Sema7a) is involved in axon growth, inflammatory responses, and immune regulation; however, its role in PVR and regulatory mechanisms in retinal pigment epithelium (RPE) cells remains unclear. This study aimed to examine Sema7a in PVR and the underlying mechanisms. Transcriptome sequencing was used to investigate the changes in mRNA expression profiles. Western blotting, immunofluorescence, and real-time polymerase chain reaction (RT-PCR) were utilized to investigate the potential mechanism of Sema7a on epithelial-mesenchymal transition (EMT) in RPE cells. Stimulating RPE cells with transforming growth factor beta-1 (TGF-β1) decreased the levels of epithelial markers but increased those of mesenchymal markers. Based on transcriptome sequencing, many molecules associated with PVR progression were regulated. PVR vitreous fluid proteomics data analysis showed that Sema7a significantly changed at different levels. Silencing Sema7a in RPE cells attenuated TGF-β1-induced EMT and their ability to induce experimental PVR; in contrast, recombinant Sema7a (rSema7a) directly triggered EMT in RPE cells. TGF-β1 induction mechanically activated the PI3k-AKT and MAPK pathways, while Sema7a knockdown by short interfering RNA lowered the phosphorylation of the PI3k-AKT/MAPK signaling pathway. Therefore, Sema7a may be a viable therapeutic target for PVR due to its crucial role in the TGF-β1-induced EMT of RPE cells.

Complement factor 3 (C3) has emerged as a primary therapeutic target in age-related macular degeneration (AMD) supported by genetic, histologic, and clinical trial evidence. Yet, the site(s) of action are unclear. The purpose of this study was to test the effect of C3 knockout on photoreceptors and retinal pigment epithelial cells (RPE) in the sodium iodate (NaIO₃) model, which mirrors some features of AMD. C3^-/- and WT mice, both on a C57Bl/6J background, were injected intraperitoneally with 25 mg/kg NaIO₃. Electroretinography and optical coherence tomography were performed 7 days later to assess retinal function and structure, respectively. Then, mice were euthanized for retinal immunohistochemistry, quantitative real-time PCR and enzyme-linked immunosorbent assays. NaIO₃ increased C3 protein levels in the neural retina but not RPE. WT but not C3^-/- mice showed NaIO₃-induced iC3b deposition on photoreceptor outer segments. C3^-/- mice were partially protected against photoreceptor layer thinning. There was partial preservation of rod and cone function in the C3^-/- group. Neither RPE structure nor function was protected. These results suggest outer segment opsonization contributes to photoreceptor death in this model, and that targeting C3 can protect photoreceptor structure and function when RPE cells are stressed.

Secretoneurin (SN) is a neuropeptide derived from secretogranin II (SgII), mainly are involved in neuroendocrine system. The present study is aimed to investigate the role of SN in retinal pathological neovascularization and physiological vasculature. In the study, we found the overexpression of SgII in retina of Oxygen-Induced Retinopathy (OIR) mouse model, and SgII knockdown could alleviate pathological retinal neovascularization in OIR. Conversely, SgII knockdown have no detectable effect in embryonic physiological vasculature. Experiments in vitro and in vivo further verified SN's angiogenic effect on the eye. In further, we identified that SN promoted angiogenesis via activation of Epidermal Growth Factor Receptor (EGFR), Insulin Receptor (IR), and Insulin-like Growth Factor 1 Receptor (IGF-1R), and followed by the phosphorylation of PI3K-AKT-mTOR signaling. In summarize, our study suggests that SN might be a postnatal angiogenic factor, which was critically involved in retinal pathological neovascularization, but not in embryonic retinal physiological vasculature. Moreover, we identified the receptors and the downstream signaling involved in SN induced retinal angiogenesis.

This study aims to characterize idiopathic epiretinal membrane (iERM) using proteomic analysis to enhance diagnosis and treatment strategies. In a prospective case-control clinical trial, vitreous fluids (VF) from twelve iERM patients were collected during surgery and analyzed by 2DE-based MALDI TOF-TOF MS/MS. PANTHER and STRING analyses were performed to investigate the biological relationships between the identified proteins and to determine relevant cellular pathways. A total of 148 proteins were identified, including 24 that were unique to iERM. Grouping the proteins by biological processes revealed that most were involved in cell adhesion (n = 6), proteolysis (n = 10), and complement activation (n = 8). Compared to control VF, 12 proteins were upregulated and 12 downregulated in iERM VF, with the differentially expressed proteins strongly associated with inflammation. Proteomic analysis highlighted complement and inflammatory proteins as potential biomarkers or therapeutic targets for iERM. Given that inflammation and fibrosis play critical roles in iERM, further investigation into these differential proteins holds significant clinical relevance. Despite the challenge of recruiting suitable patients, we believe the results of this study provide a valuable foundation for future research.

The detachment of the retinal neuroepithelium from the retinal pigment epithelium (RPE), often due to a retinal tear and subsequent subretinal fluid (SRF) accumulation, is a critical factor leading to photoreceptor cells (PR) death and permanent vision impairment in retinal detachment (RD) scenarios. Predicting postoperative visual recovery is challenging, even with surgical reattachment. Research has indicated that increased iron and transferrin (TF) saturation in the vitreous fluid (VF) correlates with poorer visual outcomes, suggesting a potential role for ferroptosis, a form of regulated cell death, in PR following RD. To explore this hypothesis, we analyzed the VF of RD patients for ferroptosis markers, revealing reduced levels of glutathione peroxidase 4 (GPX4), glutathione (GSH), and reduced nicotinamide adenine dinucleotide phosphate (NADPH), alongside elevated levels of Long-chain acyl-CoA synthetase 4(ACSL4), malondialdehyde (MDA), and ferrous iron. We then developed a mouse model to simulate RD and administered the iron chelator deferiprone (DFP) as a treatment. Our findings indicated that DFP mitigated ferroptosis in the retina, thereby preserving retinal architecture and function. Collectively, our study establishes the occurrence of ferroptosis in RD and demonstrates the therapeutic potential of DFP in protecting PR and treating RD.

To investigate the relationship between COL1A1 variations and the susceptibility to pathologic myopia (PM) among the general population in Northern China, we included 525 PM patients and 1105 non-myopic controls. All PM patients underwent comprehensive ophthalmologic examinations. DNA was extracted from peripheral venous blood samples and genotyped using the MassArray System. Statistical analyses, including Hardy-Weinberg equilibrium, χ² test, and linkage disequilibrium analysis, were conducted to compare the genotypic and allelic distributions of SNPs between PM patients and controls. The results showed no significant differences in the genotypic and allelic distributions of rs2075555, rs2269336, and rs1107946 between the PM and control groups. However, haplotype analysis revealed that the G-G-C and T-C-A haplotypes are risk factors for PM (G-G-C: OR = 1.399, 95% CI = 1.206-1.623, P < 0.001, Pc < 0.001; T-C-A: OR = 1.248, 95% CI = 1.064-1.456, P = 0.007, Pc = 0.021). Although individual SNPs in COL1A1 were not significantly associated with PM, specific haplotypes (G-G-C and T-C-A) were identified as risk factors. This suggests a potential role of COL1A1 in the development of PM.