Phenotypic and functional characterization of aqueous humor derived extracellular vesicles.

Extracellular vesicles (EVs) are double membrane vesicles, abundant in all biological fluids. However, the characterization of EVs in aqueous humor (AH) is still limited. The aim of the present work was to characterize EVs isolated from AH (AH-EVs) in terms of surface markers of cellular origin and functional properties. We obtained AHs from patients with cataract undergoing surgical phacoemulsification and insertion of intraocular lenses (n = 10). Nanoparticle tracking analysis, electron microscopy, super resolution microscopy and bead-based cytofluorimetry were used to characterize EVs from AH. Subsequently, we investigated the effects of AH-EVs on viability, proliferation and wound healing of human immortalized keratinocyte (HaCaT) cells in vitro in comparison with the effect of mesenchymal stromal cell-EVs (MSC-EVs). AH-EVs had a mean size of around 100 nm and expressed the classical tetraspanins (CD9, CD63 and CD81). Super resolution microscopy revealed co-expression of CD9, CD63 and CD81. Moreover, cytofluorimetric analysis highlighted the expression of mesenchymal, stem, epithelial and endothelial markers. In the in vitro wound healing assay on HaCaT cells, AH-EVs induced a significantly faster wound repair, comparable to the effects of MSC-EVs, and promoted HaCaT cell viability and proliferation. We provide evidence, herein, of the possible AH-EV origin from stromal cells, limbal epithelial/stem cells, ciliary epithelium and corneal endothelium. In addition, we showed their in vitro proliferative and regenerative capacities.

Corrigendum: Ocular effects caused by viral infections and corresponding vaccines: An overview of varicella zoster virus, measles virus, influenza viruses, hepatitis B virus, and SARS-CoV-2.

[This corrects the article DOI: 10.3389/fmed.2022.999251.].

Ocular effects caused by viral infections and corresponding vaccines: An overview of varicella zoster virus, measles virus, influenza viruses, hepatitis B virus, and SARS-CoV-2.

Many viral infections can affect vision and the visual system. Vaccination to prevent diseases is commonplace today, acting by stimulating an immune response without developing the pathology. It involves the production of persisting antibodies against the pathogen and the activation of T cells. Certain diseases have already been eradicated by rigorous vaccination campaigns, while others are hoped to be eliminated soon. Vaccines currently available on the market are largely safe, even if they can rarely cause some adverse effects, such as ocular complications. Analyzing existing literature, we aimed to compare the pathological effects on the eye due to the most common viral infections [in particular varicella zoster virus (VZV), measles virus, influenza viruses, hepatitis B virus, and SARS-CoV-2] with the possible ocular adverse effects of their relative vaccines, in order to establish a risk-benefit relationship from an ophthalmological point of view.

The Prevalence of Teleophthalmology in the Piedmont Region of Italy: Current Situation and Future Perspectives.

PURPOSE: This cross-sectional study aims to evaluate the actual prevalence of telemedicine, with a particular attention to teleophthalmology programs, in the Piedmont region of Northern Italy and investigate the prospects of the discipline, comparing the situation with the rest of Italy. Information about the current teleophthalmological development is important to assess the state-of-the-art of innovation in medicine in different areas of the world so that there can be a healthy comparison and evaluation of progress and backlog. METHODS: We sent questionnaires to every Local Healthcare Authority and gathered the answers in five distinct categories. Due to the COVID-19 pandemic, we collected information by telephone. We investigated five primary areas: what type of telemedicine services are currently in operation, how they are managed, the presence of any evaluation of patient satisfaction and cost-savings, and the prospects of future teleophthalmology programs to be implemented. RESULTS: Only 2% of the total telemedicine programs are in the field of ophthalmology. The greater parts are in the field of cardiology (15%) and endocrinology (13%). Currently, only one program of teleophthalmology exists in the territory, and at least four more projects are waiting to be approved or funded. Surveys about patient satisfaction were not provided and there was no evidence of cost-saving. CONCLUSIONS: Teleophthalmology in Piedmont is slowly developing, although there is a lack of a unified network for storing and managing patients' data. During the COVID-19 pandemic, telemedicine usage drastically increased, and there is a need to evaluate this trend to understand its place in the future of medicine.

Mesenchymal Stem Cell-Derived Extracellular Vesicles Protect Human Corneal Endothelial Cells from Endoplasmic Reticulum Stress-Mediated Apoptosis.

Corneal endothelial dystrophy is a relevant cause of vision loss and corneal transplantation worldwide. In the present study, we analyzed the effect of mesenchymal stem cell (MSC)-derived extracellular vesicles (MSC-EVs) in an in vitro model of corneal dystrophy, characterized by endoplasmic reticulum stress. The effects of MSC-EVs were compared with those of serum-derived EVs, reported to display a pro-angiogenic activity. MSC-EVs were able to induce a significant down-regulation of the large majority of endoplasmic reticulum stress-related genes in human corneal endothelial cells after exposure to serum deprivation and tunicamycin. In parallel, they upregulated the Akt pathway and limited caspase-3 activation and apoptosis. At variance, the effect of the serum EVs was mainly limited to Akt phosphorylation, with minimal or absent effects on endoplasmic reticulum stress modulation and apoptosis prevention. The effects of MSC-EVs were correlated to the transfer of numerous endoplasmic reticulum (ER)-stress targeting miRNAs to corneal endothelial cells. These data suggest a potential therapeutic effect of MSC-EVs for corneal endothelial endoplasmic reticulum stress, a major player in corneal endothelial dystrophy.

Effect of Stem Cell-Derived Extracellular Vesicles on Damaged Human Corneal Endothelial Cells.

PURPOSE: Human corneal endothelial cells (HCECs) are essential to visual function; however, since they have limited proliferative capacity in vivo, they are prone to corneal endothelial dysfunction. At present, the only treatment is a corneal transplantation from donor cadavers. Also, due to a global shortage of donor corneas, it is important to find alternative strategies. Recent studies highlight that stem cell-derived extracellular vesicles (EVs) play a relevant role in stem cell-induced regeneration by reprogramming injured cells and inducing proregenerative pathways. The aim of this work is to evaluate whether EVs derived from mesenchymal stem cells (MSC-EVs) are able to promote regeneration of damaged HCECs. METHODS: We isolated HCECs from discarded corneas in patients undergoing corneal transplantation or enucleation (N = 23 patients). Bone marrow mesenchymal stem cells (MSCs) were obtained from Lonza, cultured, and characterized. MSC-EVs were obtained from supernatants of MSCs. In order to establish a valid in vitro damage model to test the regenerative potential of EVs on HCECs, we evaluated the proliferation rate and the apoptosis after exposing the cells to serum-deprived medium at different concentrations for 24 hours. We then evaluated the HCEC migration through a wound healing assay. RESULTS: In the selected serum deprivation damage conditions, the treatment with different doses of MSC-EVs resulted in a significantly higher proliferation rate of HCECs at all the tested concentrations of EVs (5-20 × 103 MSC-EV/cell). MSC-EVs/cell induced a significant decrease in number of total apoptotic cells after 24 hours of serum deprivation. Finally, the wound healing assay showed a significantly faster repair of the wound after HCEC treatment with MSC-EVs. CONCLUSIONS: Results highlight the already well-known proregenerative potential of MSC-EVs in a totally new biological model, the endothelium of the cornea. MSC-EVs, indeed, induced proliferation and survival of HCECs, promoting the migration of HCECs in vitro.

Bacterial etiology and antimicrobial resistance trends in ocular infections: A 30-year study, Turin area, Italy.

PURPOSE: Bacterial ocular infections can result in loss of all or part of the ocular structures, contributing to a high disability charge. Local surveillance of etiology and susceptibility patterns is crucial for an appropriate empiric management of ocular infections. The aim of this study was to analyze of bacterial spectrum in culture-proven ocular infections and trends of antimicrobial susceptibility patterns. METHODS: A monocentric retrospective study was performed including ocular infection cases diagnosed at the Microbiology Unit of Turin Ophthalmic Hospital between 1988 and 2017. Spectrum of pathogens that caused bacterial culture-proven ocular infections and trends of antimicrobial susceptibility patterns were analyzed. RESULTS: A total of 15,517 culture-positive isolates were identified as causative agents of ocular infections. Gram-positive bacteria were deemed to cause infection in 73.5% of cases. Staphylococcus spp. and Pseudomonas spp., coagulase-negative staphylococci, Staphylococcus aureus were the leading causative pathogens of keratitis, endophthalmitis, and conjunctivitis, respectively. Statistically significant changes in temporal trends were observed for all analyzed microorganism groups except for Enterobacteriaceae group. Overall, fluoroquinolones and chloramphenicol demonstrated to be the most effective antimicrobials in vitro toward bacterial ocular infections, followed by tetracycline, ampicillin, and aminoglycosides. Enterobacteriaceae isolates showed higher multi-drug resistance rate, followed by coagulase-negative staphylococci. Analysis of resistance rates over time highlighted increasing resistance trend for aminoglycosides among Gram-negative and for both aminoglycosides and fluoroquinolones among Gram-positive pathogens, especially for S. aureus. CONCLUSION: This study provided a 30-year assessment of bacterial ocular infections in an urban area of Italy, giving support to epidemiological consciousness and guiding empiric antimicrobial therapy.

Reduction of Intraocular Pressure Spikes Due to Intravitreal Bevacizumab Injections by Scleral Indentation with Cotton Swab or Digital Ocular Massage: Innovative Techniques Compared.

PURPOSE: This study aims to evaluate the effectiveness of different decompressive injection techniques in reducing intraocular pressure (IOP) spikes, if compared to the injection without pressure applied on the eye, following the intravitreal injection of bevacizumab. PATIENTS AND METHODS: Two hundred patients with indication to intravitreal therapy were randomized into five arms: 40 received intravitreal injection without ocular decompression (arm A), 40 with pre-injection scleral indentation with cotton swab (arm B), 40 with pre-injection digital ocular massage (arm C), 40 with post-injection scleral indentation with cotton swab (arm D) and 40 with post-injection digital ocular massage (arm E). All patients underwent measurement of the IOP with Goldamm applanation tonometer 10 minutes before and 10 minutes after the injection. The primary endpoint of the study was variation of the post- injection IOP with the different techniques. RESULTS: An increase in post-injection IOP was observed in all the arms, if compared to pre-injection values. The greatest increase was observed in arm A with a mean IOP rise of 17.60 mmHg. All other techniques showed lower mean IOP increases: arm B 10.76 mmHg, arm C 9.35 mmHg, arm D 8.8 mmHg, arm E 3.4 mmHg. The post-injection IOP differences of innovative techniques compared to the technique without ocular decompression were all statistically significant (p-value <0.01). If compared to arm A (35%), a reduction in IOP spike ≥40 mmHg frequency was also observed. The status of phakia/pseudophakia, a previous diagnosis of glaucoma and the underlying pathology for which indication was given to inject bevacizumab did not significantly alter the post-injection IOP in any of the protocols. CONCLUSION: The introduction of new injection protocols, such as injections performed before or after decompressive treatments, could be a safe and effective approach to control post-injection IOP increase.

Sex Hormones and Optic Nerve Disorders: A Review.

Aim: This review article presents a comprehensive overview of the literature on sex hormones (estrogens, androgens, progesterone) and optic nerve disorders, with a discussion of the implications for therapy and prevention. Methods: Epidemiological, pre-clinical and clinical studies were reviewed. Results: Analysis of the biological basis for a relationship between eye diseases and sex hormones showed that some types of hormones can exert a protective effect either directly on the retina and optic nerve or indirectly by modulating ocular blood flow. For example, it seems that estrogen exposure has a protective effect against glaucoma, whereas its deficit may lead to early onset of the disease. If further studies confirm the data in the literature, estrogen therapy, because of its antioxidant action, may be effective in the treatment of Leber's hereditary optic neuropathy, whereas, in the light of current studies, there does not seem to be an influence of estrogen on non-arteritic anterior ischemic optic neuritis (NAION). Conclusions: Although there is some evidence that in some optic nerve pathologies the sex hormones seem to play an important role there are still too few studies providing evidence for its wider use in clinical practice.

Gonadal Hormones and Retinal Disorders: A Review.

AIM: Gonadal hormones are essential for reproductive function, but can act on neural and other organ systems, and are probably the cause of the large majority of known sex differences in function and disease. The aim of this review is to provide evidence for this hypothesis in relation to eye disorders and to retinopathies in particular. METHODS: Epidemiological studies and research articles were reviewed. RESULTS: Analysis of the biological basis for a relationship between eye diseases and hormones showed that estrogen, androgen, and progesterone receptors are present throughout the eye and that these steroids are locally produced in ocular tissues. Sex hormones can have a neuroprotective action on the retina and modulate ocular blood flow. There are differences between the male and the female retina; moreover, sex hormones can influence the development (or not) of certain disorders. For example, exposure to endogenous estrogens, depending on age at menarche and menopause and number of pregnancies, and exposure to exogenous estrogens, as in hormone replacement therapy and use of oral contraceptives, appear to protect against age-related macular degeneration (both drusenoid and neurovascular types), whereas exogenous testosterone therapy is a risk factor for central serous chorioretinopathy. Macular hole is more common among women than men, particularly in postmenopausal women probably owing to the sudden drop in estrogen production in later middle age. Progestin therapy appears to ameliorate the course of retinitis pigmentosa. Diabetic retinopathy, a complication of diabetes, may be more common among men than women. CONCLUSION: We observed a correlation between many retinopathies and sex, probably as a result of the protective effect some gonadal hormones may exert against the development of certain disorders. This may have ramifications for the use of hormone therapy in the treatment of eye disease and of retinal disorders in particular.