Ocular Surface Infection Mediated Molecular Stress Responses: A Review.

Infection mediated ocular surface stress responses are activated as early defense mechanisms in response to host cell damage. Integrated stress responses initiate the host response to different types of infections and modulate the transcription of key genes and translation of proteins. The crosstalk between host and pathogen results in profound alterations in cellular and molecular homeostasis triggering specific stress responses in the infected tissues. The amplitude and variations of such responses are partly responsible for the disease severity and clinical sequelae. Understanding the etiology and pathogenesis of ocular infections is important for early diagnosis and effective treatment. This review considers the molecular status of infection mediated ocular surface stress responses which may shed light on the importance of the host stress-signaling pathways. In this review, we collated literature on the molecular studies of all ocular surface infections and summarize the results from such studies systematically. Identification of important mediators involved in the crosstalk between the stress response and activation of diverse signaling molecules in host ocular surface infection may provide novel molecular targets for maintaining the cellular homeostasis during infection. These targets can be then explored and validated for diagnostic and therapeutic purposes.

Evaluating the safety and efficacy of compression sutures with intracameral perfluoropropane (C3F8) in the management of acute corneal hydrops.

BACKGROUND: To evaluate the safety and efficacy of using corneal compression sutures with intracameral perfluoropropane (C3F8) in patients presenting with acute corneal hydrops in ectatic disorders. METHODS: A retrospective analysis was done for 43 eyes of patients of acute corneal hydrops, managed using a combination of intracameral 14% C3F8 and full-thickness compression sutures. Time for resolution of edema, corneal thickness (CT) change on anterior segment ocular coherence tomography (ASOCT), and visual outcomes were assessed. RESULTS: Corneal edema resolved with a mean duration of 14.8 ± 3.5 days (range 10-21). The mean CT on ASOCT decreased from a mean of 1437 µm (689-2770 µm) preoperatively to 543 µm (434 -66 µm) on the complete resolution of corneal edema. CONCLUSION: Our results suggest that full-thickness compression sutures and intracameral C3F8 injection can restore the imperviousness of posterior stroma. This technique appears to be a safe and effective technique for faster resolution of corneal edema post hydrops.

Parental timing of allergenic food introduction in urban and suburban populations.

BACKGROUND: Recommendations on timing for introduction of allergenic foods in an infant diet have changed twice during the past decade. How families with different demographic characteristics implement the change has not been studied in the United States. OBJECTIVE: To compare the age of introduction of allergenic foods between an urban Medicaid-based population and a suburban private insurance-based population in Cincinnati, Ohio. METHODS: Two hundred parent surveys were distributed at well-child checkups between 4 and 36 months of age. Data were analyzed using distribution mapping to determine the difference in the age of introduction of infant formula, infant solids, whole cow's milk, eggs, peanut, and fish. Random forest analysis was used to determine the most important factors affecting the age of introduction for both populations. RESULTS: There was no statistically significant difference in the age of infant solid introduction, but urban populations introduced allergenic foods earlier than suburban populations, with a statistically significant difference in the age of introduction of infant formula, whole cow's milk, eggs, peanut, and fish. The most important factor for the timing of all food introductions was the recommended age of introduction from health care professionals. CONCLUSION: There is a difference between urban and suburban populations in the timing of introduction of allergenic foods but not in other infant solid foods. The reliance on physician recommendation for both populations supports the need for education and guidance to health care professionals on up-to-date guidance and recommendations.

Private equity in radiology - Why aren't we more concerned?

There has been recent scrutiny of private equity involvement in the healthcare market by federal and state governmental agencies who are concerned about the corporatization and financialization of healthcare in the United States. Data is emerging that patient costs increase, quality of healthcare decreases, physician autonomy decreases, and physician burnout and moral injury increases when corporate interests like private equity enter the medical market. Like other medical specialties, the field of radiology has been affected by corporatization and radiologists should understand how private equity interests may affect individual radiologists and the radiology workforce on a larger scale.

Spike sign - To predict the formation of big bubble in deep anterior lamellar keratoplasty in advanced keratoconus.

Lamellar surgeries have revolutionized our understanding and practice of keratoplasties. However, the learning curve in deep anterior lamellar keratoplasty (DALK) makes it daunting for novice surgeons. This paper describes a unique intraoperative sign - the radial "spike sign," which heralds the commencement of a big bubble in some cases of advanced keratoconus in eyes that have not undergone any previous surgery. The spike sign was noted during big bubble DALK surgery and was then retrospectively looked for in recorded DALK surgical videos and correlated with the formation of a big bubble. The movement of air after injection was classified into the direct formation of a big bubble, stromal emphysema with no big bubble, and emphysema with the spike sign followed by a big bubble. In total, 104 surgical videos of big bubble attempts were evaluated and classified as such. The spike sign helps reduce the number of unnecessary attempts at big bubble formation during DALK, thus improving surgical outcomes.

Elevated neutrophils and reduced NK cells are associated with altered tear molecular signatures and clinical sequelae of chronic ocular Stevens-Johnson syndrome.

PURPOSE: Stevens-Johnson syndrome (SJS) is characterised as an immuno-inflammatory condition with potentially blinding ocular sequelae. Therefore, we have investigated the ocular surface immune cell profile and correlated it with secreted tear molecular factors and clinical ocular sequelae in SJS patients. METHODS: 21 patients (42 eyes) with chronic ocular SJS and 16 healthy controls (20 eyes) were included in the study. Severity, types of keratopathies and ocular surface (OS) manifestations were determined. OS wash samples from study subjects were used to determine the status of 13 immune cell subsets using flow cytometry. Levels of 42 secreted immuno-inflammatory factors were measured by flow cytometry-based multiplex ELISA in tear samples. RESULTS: Neutrophils (Total, activated), neutrophils/NK cells ratio, neutrophils/T cells ratio were significantly (p < 0.05) elevated in SJS, while, proportions of T cells and NKT cells were significantly lower in SJS patients. Positive association between neutrophils and chronic ocular surface complication score (COCS) was observed, whereas, a negative association was noted between NK cells and COCS. Tear fluid levels of IL-6, IL-8, IL-18, IFNα/ß/γ, TNFα, LIF, IL-8, HGF, sTNFR-I, NGAL, Granzyme, Perforins, MMP9/TIMP1 ratio were significantly higher in SJS. Loss of Limbal niche correlated significantly with immune profile and clinical sequelae. Increased neutrophils, decreased NK cells and specific set of altered secreted immuno-inflammatory mediators including bFGF, and IL-8 were observed in SJS patients with different types of keratopathies compared to those without keratopathy. CONCLUSION: Distinct ocular surface immune profile variations were observed to correlate with clinical stages of chronic ocular SJS. Our findings uncover novel mechanisms and potential for targeted therapy in chronic ocular SJS patients.

Proteogenomic analysis of Serratia marcescens using computational subtractive genomics approach.

Serratia marcescens, a Gram-negative bacterium (Enterobacteriaceae) is a hospital-acquired opportunistic pathogen that infects the urinary and central nervous systems. The identification of new therapeutics against S. marcescens is crucial since it is now multi-drug resistant. Therefore, the current study was aimed to identify potential drug targets against S. marcescens strains i.e. WW4, SM39, and Db11 using comparative metabolic pathway analysis and subtractive genomics approach. The applied bioinformatics-based method was used to identify the unique metabolic pathways as the prioritized drug targets. The downstream analysis has led to the identification of three pathways that are specifically absent and/or present in the specific strain. Consequently, six proteins were identified through subtractive genomic analysis. The identified proteins were found as non-homologous and essential to the pathogen's survival as well as unique to the WW4 strain. The estimated features proposed it as a potential drug target. The selected protein was further subjected to in-depth structural analysis for the structure modeling, structure validation, and protein-protein interaction analysis. Furthermore, the library of ~1500 approved compounds was screened against selected drug target to identify potential drug candidates. The current work may help in repurposing of the drug compounds as novel medication against S. marcescens.

The Gene Network Correlation Analysis of Obesity to Type 1 Diabetes and Cardiovascular Disorders: An Interactome-Based Bioinformatics Approach.

The current study focuses on the importance of Protein-Protein Interactions (PPIs) in biological processes and the potential of targeting PPIs as a new treatment strategy for diseases. Specifically, the study explores the cross-links of PPIs network associated with obesity, type 1 diabetes mellitus (T1DM), and cardiac disease (CD), which is an unexplored area of research. The research aimed to understand the role of highly connected proteins in the network and their potential as drug targets. The methodology for this research involves retrieving genes from the NCBI online gene database, intersecting genes among three diseases (type 1 diabetes, obesity, and cardiovascular) using Interactivenn, determining suitable drug molecules using NetworkAnalyst, and performing various bioinformatics analyses such as Generic Protein-Protein Interactions, topological properties analysis, function enrichment analysis in terms of GO, and Kyoto Encyclopedia of Genes and Genomes (KEGG), gene co-expression network, and protein drug as well as protein chemical interaction network. The study focuses on human subjects. The results of this study identified 12 genes [VEGFA (Vascular Endothelial Growth Factor A), IL6 (Interleukin 6), MTHFR (Methylenetetrahydrofolate reductase), NPPB (Natriuretic Peptide B), RAC1 (Rac Family Small GTPase 1), LMNA (Lamin A/C), UGT1A1 (UDP-glucuronosyltransferase family 1 membrane A1), RETN (Resistin), GCG (Glucagon), NPPA (Natriuretic Peptide A), RYR2 (Ryanodine receptor 2), and PRKAG2 (Protein Kinase AMP-Activated Non-Catalytic Subunit Gamma 2)] that were shared across the three diseases and could be used as key proteins for protein-drug/chemical interaction. Additionally, the study provides an in-depth understanding of the complex molecular and biological relationships between the three diseases and the cellular mechanisms that lead to their development. Potentially significant implications for the therapy and management of various disorders are highlighted by the findings of this study by improving treatment efficacy, simplifying treatment regimens, cost-effectiveness, better understanding of the underlying mechanism of these diseases, early diagnosis, and introducing personalized medicine. In conclusion, the current study provides new insights into the cross-links of PPIs network associated with obesity, T1DM, and CD, and highlights the potential of targeting PPIs as a new treatment strategy for these prevalent diseases.

Evaporative dry eye disease due to meibomian gland dysfunction: Preferred practice pattern guidelines for diagnosis and treatment.

Evaporative dry eye (EDE) due to meibomian gland dysfunction (MGD) is one of the common clinical problems encountered in ophthalmology. It is a major cause of dry eye disease (DED) and of ocular morbidity. In EDE, inadequate quantity or quality of lipids produced by the meibomian glands leads to faster evaporation of the preocular tear film and symptoms and signs of DED. Although the diagnosis is made using a combination of clinical features and special diagnostic test results, the management of the disease might be challenging as it is often difficult to distinguish EDE from other subtypes of DED. This is critical because the approach to the treatment of DED is guided by identifying the underlying subtype and cause. The traditional treatment of MGD consists of warm compresses, lid massage, and improving lid hygiene, all measures aimed at relieving glandular obstruction and facilitating meibum outflow. In recent years, newer diagnostic imaging modalities and therapies for EDE like vectored thermal pulsation and intense pulsed light therapy have emerged. However, the multitude of management options may confuse the treating ophthalmologist, and a customized rather than a generalized approach is necessary for these patients. This review aims to provide a simplified approach to diagnose EDE due to MGD and to individualize treatment for each patient. The review also emphasizes the role of lifestyle modifications and appropriate counseling so that patients can have realistic expectations and enjoy a better quality of life.

Modulation of mucin secretion using combined polyethylene glycol-propylene glycol topical formulation in a hyperosmotic stress-based explant model.

Purpose: Ocular surface discomfort and dry eye disease are caused by a dysfunctional tear film. The efficacy of lubricating eye drops on the human eye is known, but the compositions may show differential effects on rescuing the tear film. Mucins form a critical layer of the tear film, a reduction of which may be causative for ocular surface conditions. Therefore, it is essential to develop relevant human-derived models to test mucin production. Methods: Human corneoscleral rims were obtained from a healthy donor (n = 8) post-corneal keratoplasty and cultured in DMEM/F12 media. Hyperosmolar stress mimicking dry eye disease was induced by exposing the corneoscleral rim tissues to +200 mOsml NaCl-containing media. The corneoscleral rims were treated with polyethylene glycol-propylene glycol (PEG-PG)-based topical formulation. Gene expression analysis was performed for NFAT5, MUC5AC, and MUC16. Secreted mucins were measured by enzyme-linked immunosorbent assay (ELISA) (Elabscience, Houston, TX, USA) for MUC5AC and MUC16. Results: The corneoscleral rims responded to hyperosmolar stress by upregulating NFAT5, a marker for increased osmolarity, as observed in the case of dry eye disease. The expression of MUC5AC and MUC16 was reduced upon an increase in hyperosmotic stress. The corneoscleral rim tissues showed induction of MUC5AC and MUC16 expression upon treatment with PEG-PG topical formulation but did not show significant changes in the presence of hyperosmolar treatments. Conclusion: Our findings showed that PEG-PG-based topical formulation slightly alleviated hyperosmolar stress-induced decrease in MUC5AC and MUC16 gene expression that is encountered in DED.

Corneal Regeneration Using Gene Therapy Approaches.

One of the most remarkable advancements in medical treatments of corneal diseases in recent decades has been corneal transplantation. However, corneal transplants, including lamellar strategies, have their own set of challenges, such as graft rejection, delayed graft failure, shortage of donor corneas, repeated treatments, and post-surgical complications. Corneal defects and diseases are one of the leading causes of blindness globally; therefore, there is a need for gene-based interventions that may mitigate some of these challenges and help reduce the burden of blindness. Corneas being immune-advantaged, uniquely avascular, and transparent is ideal for gene therapy approaches. Well-established corneal surgical techniques as well as their ease of accessibility for examination and manipulation makes corneas suitable for in vivo and ex vivo gene therapy. In this review, we focus on the most recent advances in the area of corneal regeneration using gene therapy and on the strategies involved in the development of such therapies. We also discuss the challenges and potential of gene therapy for the treatment of corneal diseases. Additionally, we discuss the translational aspects of gene therapy, including different types of vectors, particularly focusing on recombinant AAV that may help advance targeted therapeutics for corneal defects and diseases.

Role of in vivo confocal microscopy in dry eye disease and eye pain.

Dry eye disease is known to have a lot of variability in presentation with overlapping subtypes. Understanding the pathology of this condition will guide therapeutic options. In vivo confocal microscopy is a diagnostic and imaging modality that provides high magnification and high-resolution images of all layers of the cornea and ocular surface. Various structures in the cornea and their alterations due to dry eye have been imaged. The impact of the tear film instability, inflammation, and altered homeostasis on the corneal epithelium, nerves, keratocytes, and dendritic cells have been evaluated across different studies. In addition, key features of IVCM in patients with neuropathic pain have been highlighted in this paper.

Ion channels in dry eye disease.

Dry eye disease (DED) which affects millions of people worldwide is an ocular surface disease that is strongly associated with pain, discomfort, and visual disturbances. Altered tear film dynamics, hyperosmolarity, ocular surface inflammation, and neurosensory abnormalities are the key contributors to DED pathogenesis. The presence of discordance between signs and symptoms of DED in patients and refractoriness to current therapies in some patients underpin the need for studying additional contributors that can be modulated. The presence of electrolytes or ions including sodium, potassium, chloride, bicarbonate, calcium, and magnesium in the tear fluid and ocular surface cells contribute to ocular surface homeostasis. Ionic or electrolyte imbalance and osmotic imbalance have been observed in DED and feed-forward interaction between ionic imbalances and inflammation alter cellular processes in the ocular surface resulting in DED. Ionic balances in various cellular and intercellular compartments are maintained by dynamic transport via ion channel proteins present in cell membranes. Hence, alterations in the expression and/or activity of about 33 types of ion channels that belong to voltage-gated channels, ligand-gated channels, mechanosensitive ion channel, aquaporins, chloride ion channel, sodium-potassium-chloride pumps or cotransporters have been investigated in the context of ocular surface health and DED in animal and/or human subjects. An increase in the expression or activity of TRPA1, TRPV1, Nav1.8, KCNJ6, ASIC1, ASIC3, P2X, P2Y, and NMDA receptor have been implicated in DED pathogenesis, whereas an increase in the expression or activity of TRPM8, GABAA receptor, CFTR, and NKA have been associated with resolution of DED.

Systemic investigations in dry eye disease.

The incidence of dry eye disease has increased manifold in the past few years with more patients presenting with these complaints to our clinics every day. In the more severe forms of disease, it is important to evaluate for any systemic association which could be driving the disease such as in Sjogren's syndrome. Understanding the possible varied etiopathogenesis and knowing when to evaluate, form an important part of treating this condition effectively. In addition, it is sometimes confusing as to which investigations to order and how to prognosticate the disease in these situations. This article simplifies this into an algorithmic approach with insights from the ocular and systemic point of view.

A randomized controlled study evaluating outcomes of intense pulsed light and low-level light therapy for treating meibomian gland dysfunction and evaporative dry eye.

Purpose: This randomized, controlled, blinded study evaluates the efficacy of intense pulsed light (IPL) therapy with low-level light therapy (LLLT) in the treatment of meibomian gland dysfunction (MGD) and evaporative dry eye (EDE) compared to a control group. Methods: Hundred patients with MGD and EDE were randomized into control (50 subjects, 100 eyes) and study group (50 subjects, 100 eyes). The study group underwent three sittings of IPL with LLLT 15 days apart and were followed up 1 month and 2 months after the last treatment sitting. The control group underwent sham treatment and was followed up at the same intervals. The patients were evaluated at baseline and 1 month and 3 months (post 1st treatment) for dry eye. Schirmer's test and tear breakup time (TBUT), OSDI, meibomian gland expression, and meibography. Results: The study group showed significant improvement in OSDI scores (P < 0.0001) compared to the control group and a significant improvement in TBUT (P < 0.005) compared to the control group. There was no change in schirmer's test and an improvement in the meibomian gland expression but not significant. Conclusion: The results show that a combined therapy of IPL with LLT is effective in treating MGD with EDE compared to controls, and repeated treatment sessions have a cumulative effect on the disease outcomes.

Effect of maqui-berry extract in dry eye disease - A clinical and molecular analysis.

Purpose: This study aims to investigate the effects of maqui-berry extract (MBE) in improving signs and symptoms of dry eye disease (DED) along with ocular surface inflammation in patients with DED. Methods: Twenty patients were randomly assigned to a MBE or a placebo group (PLC). DED parameters including Schirmer's test 1 (ST1), tear film break-up time (TBUT), ocular surface disease index (OSDI), and corneal staining were assessed before treatment and 2 months post-treatment. Tear fluid samples before and after treatment from a subset of these patients were collected from the study subjects using sterile Schirmer's strips, and the levels of interleukin (IL)-1ß, IL-10, IL-6, IL-17A, tumor necrosis factor-α (TNFα), matrix metalloproteinase-9 (MMP9), soluble intercellular adhesion molecule-1 (sICAM1), and vascular endothelial growth factor-A (VEGF-A) were measured using a microfluidic cartridge-based multiplex ELISA. Results: The MBE group demonstrated a significant (p < 0.05) decrease in OSDI scores along with a significant increase in Schirmer's test 1 compared to the PLC group. No significant change in TBUT and corneal staining was observed between the study groups. Levels of proinflammatory factors such as IL-1ß, IL-6, IL-17A, TNFα, and MMP9 were observed to be significantly reduced, along with a significant increase in IL-10 levels following treatment in the MBE group compared with the PLC group. Conclusion: Consumption of MBE resulted in the resolution of DED signs and symptoms, along with a reduction in ocular surface inflammation.

Tear biomarkers in dry eye disease: Progress in the last decade.

Dry eye disease (DED) is a commonly occurring, multifactorial disease characterized by reduced tear film stability and hyperosmolarity at the ocular surface, leading to discomfort and visual compromise. DED is driven by chronic inflammation and its pathogenesis involves multiple ocular surface structures such as the cornea, conjunctiva, lacrimal glands, and meibomian glands. The tear film secretion and its composition are regulated by the ocular surface in orchestration with the environment and bodily cues. Thus, any dysregulation in ocular surface homeostasis causes an increase in tear break-up time (TBUT), osmolarity changes, and reduction in tear film volume, all of which are indicators of DED. Tear film abnormalities are perpetuated by underlying inflammatory signaling and secretion of inflammatory factors, leading to the recruitment of immune cells and clinical pathology. Tear-soluble factors such as cytokines and chemokines are the best surrogate markers of disease severity and can also drive the altered profile of ocular surface cells contributing to the disease. Soluble factors can thus help in disease classification and planning treatment strategies. Our analysis suggests increased levels of cytokines namely interleukin-1ß (IL-1ß), IL-2, IL-4, IL-6, IL-9, IL-12, IL-17A, interferon-gamma (IFN-γ), tumor necrosis factor-alpha (TNF-α); chemokines (CCL2, CCL3, CCL4, CXCL8); MMP-9, FGF, VEGF-A; soluble receptors (sICAM-1, sTNFR1), neurotrophic factors (NGF, substance P, serotonin) and IL1RA and reduced levels of IL-7, IL-17F, CXCL1, CXCL10, EGF and lactoferrin in DED. Due to the non-invasive sample collection and ease of quantitively measuring soluble factors, tears are one of the best-studied biological samples to molecularly stratify DED patients and monitor their response to therapy. In this review, we evaluate and summarize the soluble factors profiles in DED patients from the studies conducted over the past decade and across various patient groups and etiologies. The use of biomarker testing in clinical settings will aid in the advancement of personalized medicine and represents the next step in managing DED.

Ocular surface immune cell diversity in dry eye disease.

Dry eye disease (DED) is a multifactorial chronic ocular surface inflammatory condition. Disease severity has been directly related to the immuno-inflammatory status of the ocular surface. Any perturbation in the orchestrated functional harmony between the ocular surface structural cells and immune cells, both resident and trafficking ones, can adversely affect ocular surface health. The diversity and contribution of ocular surface immune cells in DED have been of interest for over a couple of decades. As is true with any mucosal tissue, the ocular surface harbors a variety of immune cells of the innate-adaptive continuum and some of which are altered in DED. The current review curates and organizes the knowledge related to the ocular surface immune cell diversity in DED. Ten different major immune cell types and 21 immune cell subsets have been studied in the context of DED in human subjects and in animal models. The most pertinent observations are increased ocular surface proportions of neutrophils, dendritic cells, macrophages, and T cell subsets (CD4+; CD8+; Th17) along with a decrease in T regulatory cells. Some of these cells have demonstrated disease-causal association with ocular surface health parameters such as OSDI score, Schirmer's test-1, tear break-up time, and corneal staining. The review also summarizes various interventional strategies studied to modulate specific immune cell subsets and reduce DED severity. Further advancements would enable the use of ocular surface immune cell diversity, in patient stratification, i.e. DED-immunotypes, disease monitoring, and selective targeting to resolve the morbidity related to DED.

Type 1-type 2 interferon imbalance in dry eye disease.

Purpose: Dry eye disease (DED) is characterized by altered ocular surface proinflammatory and antiinflammatory factors. Interferons (IFNs) are a class of pleiotropic cytokines well known for their antimicrobial, inflammatory, and immunomodulatory roles. Hence, this study investigates the ocular surface expression of different types of IFNs in patients with DED. Methods: The cross-sectional, observational study included patients with DED and normal subjects. Conjunctival impression cytology (CIC) samples were obtained from the study subjects (controls, n = 7; DED, n = 8). The mRNA expression levels of type 1 IFN (IFNα, IFNß), type 2 IFN (IFNγ), and type 3 IFN (IFNλ1, IFNλ2, IFNλ3) were measured by quantitative PCR (polymerase chain reaction) in CIC samples. IFNα and IFNγ expression under hyperosmotic stress was also studied in human corneal epithelial cells (HCECs) in vitro. Results: The mRNA expression levels of IFNα and IFNß were significantly lower and that of IFNγ was significantly higher in DED patients compared to healthy controls. The mRNA levels of IFNα, IFNß, and IFNλ were significantly lower compared to IFNγ in DED patients. An inverse association between tonicity-responsive enhancer-binding protein (TonEBP; hyperosmotic stress maker) and IFNα or IFNß expression and a positive association between TonEBP and IFNγ expression was observed in CIC samples. The expression of IFNα was lower than IFNγ in HCECs undergoing hyperosmotic stress compared to HCECs without the stress. Conclusion: The presence of an imbalance between type 1 and type 2 IFNs in DED patients suggests newer pathogenic processes in DED, plausible ocular surface infection susceptibility in DED patients, and potential therapeutic targets in the management of DED.