Topical Application of Liriope platyphylla Extract Attenuates Dry Eye Syndrome Induced by Particulate Matter

Topical Porphyrin Antioxidant Protects Against Ocular Surface Pathology in a Novel Rabbit Model for Particulate Matter-Induced Dry Eye Disease

Purpose: Particulate matter (PM) is a primary cause for the development of acute and chronic dry eye disease, especially irritant-induced conjunctivitis. The purpose of the present study was to determine the effects of fine atmospheric PM on the rabbit ocular surface, and determine the protective effects of a synthetic antioxidant, manganese(III) tetrakis(1-methyl-4-pyridyl) porphyrin (Mn-TM-2-PyP), in vitro and in vivo. Methods: Rabbit corneal epithelial cells (SIRC) were exposed to increasing concentrations of PM to determine the effects on cell motility and viability. The in vivo effects of topically instilled PM were tested in New Zealand White rabbits. Comprehensive ophthalmic exams and corneal fluorescein staining were performed. Results: Exposure to PM resulted in dose-dependent cell death and impaired cellular motility; Mn-TM-2-PyP protected against PM-induced cytotoxicity and significantly increased SIRC cell motility. In vivo, exposure to PM (5 mg/ml, topical, 3 times daily for 7 days) resulted in signs of dry eye, notably hyperemia, increased corneal fluorescein staining, and decreased tear volumes. Mn-TM-2-PyP significantly improved hyperemia and corneal fluorescein readouts but had no effect on tear production. Lifitegrast (Xiidra^®) showed similar pharmacologic efficacy to Mn-TM-2-PyP. Conclusion: Overall, these data provide evidence that PM induces phenotypes of ocular surface disease responsive to antioxidant and immunosuppressant therapy. To our knowledge this is the first report of a large animal model to study PM-induced ocular surface disease. The present work provides standardized experimental paradigms for the comprehensive in vitro and in vivo testing of novel therapeutic approaches targeting PM-induced conjunctivitis and dry-eye.

Liriopogons (Genera Ophiopogon and Liriope, Asparagaceae): A Critical Review of the Phytochemical and Pharmacological Research

The closely related genera Liriope and Ophiopogon (Asparagaceae), collectively known in English as liriopogons, have similar therapeutic uses in treating cough, rheumatoid arthritis, and cleaning heat. The main aim of this review is to understand the current phytochemical and pharmacological knowledge including an assessment of the quality of the scientific evidence. A literature search was conducted in line with PRISMA guidelines, by retrieving available information up to 2020 from five online resources. The bioactive metabolites of liriopogons include steroidal saponins, flavonoids, polysaccharides, organic acids, phenols. Cardiovascular protective, anti-inflammatory, anti-diabetic, anti-oxidant, anti-cancer, neuroprotective, anti-viral, anti-acute myeloid leukemia and hepatoprotective effects have been at the center of attention. From a toxicological perspective Ophiopogon japonicus seems to be safe. Some problems with the quality of the pharmacological evidence stand out including the application of excessive dose level and methodological problems in the design. Additionally, a reasonable link between local/traditional uses and pharmacological assessment is often vague or not reflected in the text. Future researches on liriopogons are required to use rigorous scientific approaches in research on evidence-based natural products for the future benefits of patients.

Retrospective evaluation of the curative effect of traditional Chinese medicine on dry eye disease

Dry eye disease (DED) is a multifactorial illness with an increasingly high global prevalence and multiple risk factors that widely influences patients’ daily lives. It is essential to identify treatments with few or no side effects for patients with DED. We have reviewed studies published from 2001 to 2020 that investigated traditional Chinese medicine (TCM) and integrated Chinese and Western medicine for DED treatment. Current Chinese medicines used in DED therapy were categorized into four types, namely anti-oxidants, anti-inflammatory agents, hormone-like agents, and cell-repairing agents. Compound herbs, including Chi-Ju-Di-Huang-Wan and Qiming granule, can effectively alleviate dry eye symptoms. Moreover, patients with DED who were treated with Western medicine combined with TCM experienced significantly magnified therapeutic effects and reasonable costs of treatment. In conclusion, TCM can be a promising approach for treating DED, and combined treatment with TCM and Western drugs may represent a new strategy for improving the curative effect.

The Protective Effect of Oral Application of Corni Fructus on the Disorders of the Cornea, Conjunctiva, Lacrimal Gland and Retina by Topical Particulate Matter 2.5

Particulate matter 2.5 (PM_2.5) may aggravate dry eye disease (DED). Corni Fructus (CF), which is fruit of Cornus officinalis Sieb. et Zucc., has been reported to have various beneficial pharmacological effects, whereas the effect of CF on the eye is still unknown. Therefore, in this study, we investigated the effect of oral administration of water extract of CF (CFW) on the eye, hematology, and biochemistry in a DED model induced by topical exposure to PM_2.5. Furthermore, the efficacy of CFW compared with cyclosporine (CsA), an anti-inflammatory agent, and lutein, the posterior eye-protective agent. Sprague-Dawley rats were topically administered 5 mg/mL PM_2.5 in both eyes four times daily for 14 days. During the same period, CFW (200 mg/kg and 400 mg/kg) and lutein (4.1 mg/kg) were orally administered once a day. All eyes of rats in the 0.05% cyclosporine A (CsA)-treated group were topically exposed to 20 μL of CsA, twice daily for 14 days. Oral administration of CFW attenuated the PM_2.5-induced reduction of tear secretion and corneal epithelial damage. In addition, CFW protected against goblet cell loss in conjunctiva and overexpression of inflammatory factors in the lacrimal gland following topical exposure to PM_2.5. Furthermore, CFW markedly prevented PM_2.5-induced ganglion cell loss and recovered the thickness of inner plexiform layer. Meanwhile, CFW treatment decreased the levels of total cholesterol and low-density lipoprotein cholesterol in serum induced by PM_2.5. Importantly, the efficacy of CFW was superior or similar to that of CsA and lutein. Taken together, oral administration of CFW may have protective effects against PM_2.5-induced DED symptoms via stabilization of the tear film and suppression of inflammation. Furthermore, CFW may in part contribute to improving retinal function and lipid metabolism disorder.

The Impact of Particulate Matter (PM2.5) on Human Retinal Development in hESC-Derived Retinal Organoids

Increasing evidence demonstrated that PM2.5 could cross the placenta and fetal blood-brain barrier, causing neurotoxicity of embryonic development. The retina, an embryologic extension of the central nervous system, is extremely sensitive and vulnerable to environmental insults. The adverse effects of PM2.5 exposure on the retina during embryonic neurodevelopment are still largely unknown. Our goal was to investigate the effect of PM2.5 on human retinal development, which was recapitulated by human embryonic stem cell (hESC)-derived retinal organoids (hEROs). In the present study, using the hEROs as the model, the influences and the mechanisms of PM2.5 on the developing retina were analyzed. It demonstrated that the formation rate of the hERO-derived neural retina (NR) was affected by PM2.5 in a concentration dosage-dependent manner. The areas of hEROs and the thickness of hERO-NRs were significantly reduced after PM2.5 exposure at the concentration of 25, 50, and 100 μg/ml, which was due to the decrease of proliferation and the increase of apoptosis. Although we did not spot significant effects on retinal differentiation, PM2.5 exposure did lead to hERO-NR cell disarranging and structural disorder, especially retinal ganglion cell dislocation. Transcriptome analysis showed that PM2.5 treatment was significantly associated with the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/AKT pathways and reduced the level of the fibroblast growth factors (FGFs), particularly FGF8 and FGF10. These results provided evidence that PM2.5 exposure potentially inhibited proliferation and increased apoptosis at the early development stage of the human NR, probably through the MAPK and PI3K/Akt pathway. Our study suggested that exposure to PM2.5 suppressed cell proliferation and promoted cell apoptosis, thereby contributing to abnormal human retinal development.

MRI Characteristics of NMO, MOG and MS Related Optic Neuritis

Acute isolated optic neuritis can be the initial presentation of demyelinating inflammatory central nervous system disease related to multiple sclerosis (MS), neuromyelitis optica (NMO) or myelin oligodendrocyte glycoprotein antibody disease (MOG-AD). In addition to the well-characterized brain and spinal cord imaging features, important and characteristic differences in the radiologic appearance of the optic nerves in these disorders are being described, and magnetic resonance imaging (MRI) of the optic nerves is becoming an essential tool in the differential diagnosis of optic neuritis. Whereas typical demyelinating optic neuritis is a relatively mild and self-limited disease, atypical optic neuritis in NMO and MOG-AD is potentially much more vision-threatening and merits a different treatment approach. Thus, differentiation based on MRI features may be particularly important during the first attack of optic neuritis, when antibody status is not yet known. This review discusses the optic nerve imaging in the major demyelinating disorders with an emphasis on clinically relevant differences that can help clinicians assess and manage these important neuro-ophthalmic disorders. It also reviews the utility of optic nerve MRI as a prognostic indicator in acute optic neuritis.

Prognostic Factors for Visual Outcomes Following the First Episode of NMOSD-Related Optic Neuritis in Affected Eyes

OBJECTIVE

We aim to identify prognostic factors for visual outcomes following a first episode of neuromyelitis optica spectrum disorder-related optic neuritis (NMOSD-ON) in affected eyes.

MATERIALS AND METHODS

This was a single-center, retrospective study. The study included 50 individuals who were diagnosed with NMOSD-ON (63 affected eyes) in a tertiary institution over a 12-year period. Data regarding any second, or higher, episodes of NMOSD-ON in each eye were not taken into consideration. Medical records of included individuals were reviewed. Demographic data, clinical and magnetic resonance imaging characteristics, and treatment outcomes were collected. Main outcome measures of the study were prognostic factors for good visual outcome (best-corrected visual acuity (BCVA) ≥ 20/200) following an initial episode of NMOSD-ON in affected eyes.

RESULTS

Sixty-three affected eyes of 50 individuals (3 men and 47 women) were included. BCVA at nadir that was better than counting fingers (CF) (odds ratio 10.43, 95% confidence interval 1.04, 104.45, p = 0.046) and time from NMOSD-ON onset to intravenous methylprednisolone (IVMP), less than 21 days (odds ratio 10.73, 95% confidence interval 1.91, 60.01, p = 0.007), were significantly associated with good visual outcomes.

CONCLUSION

BCVA at nadir that was better than CF and treatment with IVMP within 21 days of symptom onset were important prognostic factors of good visual outcomes following a first episode of NMOSD-ON in affected eyes.

New application for assessment of dry eye syndrome induced by particulate matter exposure

Dry eye syndrome (DES) is a multifactorial condition characterized by insufficient tear lubrication and eye irritation. Air pollutants, including particulate matter (PM), are an emerging threat to human health causing DES and other diseases. However, the pathogenic mechanisms of DES induced by PM exposure remain to be fully elucidated. Recent studies have attempted to create DES animal model using PM exposure. In this study, we explored a novel in vivo exposure model of DES, utilizing an inhalation device (aerosol exposure system) to reproduce the natural exposure to atmospheric PM. Rats were exposed to urban PM (UPM) using this aerosol system for 5 h per day over 5 days. Tear volume in UPM-exposed rats decreased significantly, whereas corneal irregularity and lissamine green staining significantly increased following UPM exposure. Additional effects observed following UPM exposure included apoptosis in the corneal epithelium and a decrease in the number of goblet cells in the conjunctiva. UPM also affected the stability of the tear film by disrupting its mucin-4 layer. In conclusion, aerosol exposure systems have proven effective as assessment tools for DES caused by PM.