Nimisha Rajiv Kumar

Purpose: Ocular surface discomfort and dry eye disease (DED) are the most common conditions addressed by ophthalmologists worldwide. Artificial tear substitutes are used as the first line of treatment management for DED patients. The present study was performed to understand the role of artificial tear formulation namely Soha Liquigel (0.18% sodium hyaluronate with trehalose) and Soha (0.1% sodium hyaluronate) for the treatment of DED in vitro . Human corneal epithelial (HCE) cells were used in adapted cell culture conditions which induce relevant cellular and molecular modifications thus mimicking the DED. Methods: Artificial tears containing either sodium hyaluronate (SH) (Soha 0.1%, Sun Pharma) or a combination of SH with trehalose (Soha Liquigel 0.18%, Sun Pharma) were compared with respective controls to analyze the effect on desiccation-induced stress or oxidative stress or hyperosmolarity induced stress on HCE cells. Cellular viability was evaluated using the trypan blue assay, while epithelial morphology was observed under light microscopy. Real-time polymerase chain reaction (RT-PCR) was utilized to analyze the transcriptional profile of a specific set of gene signatures, namely S100A7, FOS, SOD-2, COX2, TonEBP, IL6, MCP1, and IL10. Results: The response of HCE cells to desiccation stress (24 hr) was observed through alterations in their cellular morphology, which were subsequently restored by applying Soha Liquigel. Oxidative stress was induced using 100 nM of H ₂ O ₂ on HCE cells (short- 24 h and long-term 5 days) and measured using increased expression of S100A7, an oxidative stress-responsive gene. Oxidative-stressed HCE cells after treatment with Soha Liquigel showed reduced pro-oxidant gene and COX2 expression and elevated anti-oxidant genes, FOS, and SOD levels. HCE cells were subjected to +100mOsmol and +200mOsmol NaCl-containing media, inducing hyperosmolar stress that imitates the symptoms of DED. Further, these hyperosmolar stressed cells were treated with Soha Liquigel and Soha eye drops for 24 h and 5 days. Both eye drops rescued the cell morphology under hyperosmolar conditions in both short- and long-term treatments. Increased TonEBP levels confirm the osmotic stress in HCE cells. Reduction in IL6, MCP1, TonEBP, and elevated expression of IL10 in hyperosmotic stressed HCE cells treated with either of the artificial tears indicates their osmo-protection properties. Conclusion: By using desiccation, oxidative, and hyperosmolar stress simulated in HCE cells in culture, we observed that SH-containing artificial tears provided bio-protection, osmo-protection, and anti-oxidant benefits that were further strengthened with SH and trehalose combination.

Purpose: refractive surgery, such as LASIK and SMILE, induces a wound healing response that leads to significant corneal stromal remodeling. We have shown that the protein profile in the stroma changes dramatically immediately post-surgery. However, the methylation status of the DNA post-refractive surgery remains unknown. Design/Participants: DNA methylation study. Refractive surgery (SMILE/LASIK) performed on donor eye globes. Method: we investigated the epigenetic changes post-surgery in relation to long term ECM remodeling in an experimental ex vivo study design. Donor globes (n = 19) were obtained from the eye bank. Three globes served as non-surgical controls while SMILE (-6DS) and LASIK surgery (-6DS) were performed on eight globes each and incubated for 3 days and 2 weeks (n = 4 per group per time point). Here, we compared the DNA methylation landscapes of LASIK and SMILE stroma using the Illumina Infinium Human Methylation 850 EPIC array (HM850). Results: significant changes in DNA methylation patterns were observed post-operatively in both LASIK and SMILE groups. Specific genes involved in the activation of actin cytoskeleton and inflammation (smad3, prkca and ssh2) showed hypomethylation in LASIK after 2 weeks and LASIK SMILE after 3 days, respectively, suggesting their active role in corneal repair. The genes (gaa, gstm1, mgat1, galnt9 and galnt5) involved in sphingolipid metabolism and mucin biosynthesis showed hypomethylation in SMILE after 3 days. Conclusions: our results suggest that altered DNA methylation patterns may have relevance to the development of complications of haze post-refractive surgery. It also presents the opportunity to utilize drugs that regulate chromatin remodeling for optimal outcomes.

Prolonged daily face mask wearing over several months might affect health of the ocular surface and is reported to be associated with complaints of discomfort and dry-eye-like symptoms. We studied the ocular surface clinical parameters, tear soluble factors and immune cell proportions in ophthalmologists practicing within similar environmental conditions (n = 17) at two time points: pre-face-mask period (Pre-FM; end of 2019) and post-face-mask-wearing period (Post-FM; during 2020 COVID-19 pandemic), with continuous (~8 h/day) mask wear. A significant increase in ocular surface disease index (OSDI) scores without changes in tear breakup time (TBUT), Schirmer’s test 1 (ST1) and objective scatter index (OSI) was observed Post-FM. Tear soluble factors (increased—IL-1β, IL-33, IFNβ, NGF, BDNF, LIF and TSLP; decreased—IL-12, IL-13, HGF and VEGF-A) and mucins (MUC5AC) were significantly altered Post-FM. Ex vivo, human donor and corneoscleral explant cultures under elevated CO₂ stress revealed that the molecular profile, particularly mucin expression, was similar to the Post-FM tear molecular profile, suggesting hypercapnia is a potential contributor to ocular surface discomfort. Among the immune cell subsets determined from ocular surface wash samples, significantly higher proportions of leukocytes and natural killer T cells were observed in Post-FM compared to Pre-FM. Therefore, it is important to note that the clinical parameters, tear film quality, tear molecular factors and immune cells profile observed in prolonged mask-wear-associated ocular surface discomfort were distinct from dry eye disease or other common ocular surface conditions. These observations are important for differential diagnosis as well as selection of appropriate ocular surface treatment in such subjects.