Ectopic lymphoid structures in the aged lacrimal glands.

Aging is a complex biological process in which many organs are pathologically affected. We previously reported that aged C57BL/6J had increased lacrimal gland (LG) lymphoid infiltrates that suggest ectopic lymphoid structures. However, these ectopic lymphoid structures have not been fully investigated. Using C57BL/6J mice of different ages, we analyzed the transcriptome of aged murine LGs and characterized the B and T cell populations. Age-related changes in the LG include increased differentially expressed genes associated with B and T cell activation, germinal center formation, and infiltration by marginal zone-like B cells. We also identified an age-related increase in B1+ cells and CD19+B220+ cells. B220+CD19+ cells were GL7+ (germinal center-like) and marginal zone-like and progressively increased with age. There was an upregulation of transcripts related to T follicular helper cells, and the number of these cells also increased as mice aged. Compared to a mouse model of Sjögren syndrome, aged LGs have similar transcriptome responses but also unique ones. And lastly, the ectopic lymphoid structures in aged LGs are not exclusive to a specific mouse background as aged diverse outbred mice also have immune infiltration. Altogether, this study identifies a profound change in the immune landscape of aged LGs where B cells become predominant. Further studies are necessary to investigate the specific function of these B cells during the aged LGs.

An ocular Th1 immune response promotes corneal nerve damage independently of the development of corneal epitheliopathy.

Proper sight is not possible without a smooth, transparent cornea, which is highly exposed to environmental threats. The abundant corneal nerves are interspersed with epithelial cells in the anterior corneal surface and are instrumental to corneal integrity and immunoregulation. Conversely, corneal neuropathy is commonly observed in some immune-mediated corneal disorders but not in others, and its pathogenesis is poorly understood. Here we hypothesized that the type of adaptive immune response may influence the development of corneal neuropathy. To test this, we first immunized OT-II mice with different adjuvants that favor T helper (Th)1 or Th2 responses. Both Th1-skewed mice (measured by interferon-γ production) and Th2-skewed (measured by interleukin-4 production) developed comparable ocular surface inflammation and conjunctival CD4+ T cell recruitment but no appreciable corneal epithelial changes upon repeated local antigenic challenge. Th1-skewed mice showed decreased corneal mechanical sensitivity and altered corneal nerve morphology (signs of corneal neuropathy) upon antigenic challenge. However, Th2-skewed mice also developed milder corneal neuropathy immediately after immunization and independently of ocular challenge, suggestive of adjuvant-induced neurotoxicity. All these findings were confirmed in wild-type mice. To circumvent unwanted neurotoxicity, CD4+ T cells from immunized mice were adoptively transferred to T cell-deficient mice. In this setup, only Th1-transferred mice developed corneal neuropathy upon antigenic challenge. To further delineate the contribution of each profile, CD4+ T cells were polarized in vitro to either Th1, Th2, or Th17 cells and transferred to T cell-deficient mice. Upon local antigenic challenge, all groups had commensurate conjunctival CD4+ T cell recruitment and macroscopic ocular inflammation. However, none of the groups developed corneal epithelial changes and only Th1-transferred mice showed signs of corneal neuropathy. Altogether, the data show that corneal nerves, as opposed to corneal epithelial cells, are sensitive to immune-driven damage mediated by Th1 CD4+ T cells in the absence of other pathogenic factors. These findings have potential therapeutic implications for ocular surface disorders.

Molecular mechanisms regulating wound repair: Evidence for paracrine signaling from corneal epithelial cells to fibroblasts and immune cells following transient epithelial cell treatment with Mitomycin C.

In this paper, we use RNAseq to identify senescence and phagocytosis as key factors to understanding how mitomyin C (MMC) stimulates regenerative wound repair. We use conditioned media (CM) from untreated (CMC) and MMC treated (CMM) human and mouse corneal epithelial cells to show that corneal epithelial cells indirectly exposed to MMC secrete elevated levels of immunomodulatory proteins including IL-1α and TGFß1 compared to cells exposed to CMC. These factors increase epithelial and macrophage phagocytosis and promote ECM turnover. IL-1α supplementation can increase phagocytosis in control epithelial cells and attenuate TGFß1 induced αSMA expression by corneal fibroblasts. Yet, we show that epithelial cell CM contains factors besides IL-1α that regulate phagocytosis and αSMA expression by fibroblasts. Exposure to CMM also impacts the activation of bone marrow derived dendritic cells and their ability to present antigen. These in vitro studies show how a brief exposure to MMC induces corneal epithelial cells to release proteins and other factors that function in a paracrine way to enhance debris removal and enlist resident epithelial and immune cells as well as stromal fibroblasts to support regenerative and not fibrotic wound healing.

Lacrimal Gland Epithelial Cells Shape Immune Responses through the Modulation of Inflammasomes and Lipid Metabolism.

Lacrimal gland inflammation triggers dry eye disease through impaired tear secretion by the epithelium. As aberrant inflammasome activation occurs in autoimmune disorders including Sjögren's syndrome, we analyzed the inflammasome pathway during acute and chronic inflammation and investigated its potential regulators. Bacterial infection was mimicked by the intraglandular injection of lipopolysaccharide (LPS) and nigericin, known to activate the NLRP3 inflammasome. Acute injury of the lacrimal gland was induced by interleukin (IL)-1α injection. Chronic inflammation was studied using two Sjögren's syndrome models: diseased NOD.H2b compared to healthy BALBc mice and Thrombospondin-1-null (TSP-1-/-) compared to TSP-1WTC57BL/6J mice. Inflammasome activation was investigated by immunostaining using the R26ASC-citrine reporter mouse, by Western blotting, and by RNAseq. LPS/Nigericin, IL-1α and chronic inflammation induced inflammasomes in lacrimal gland epithelial cells. Acute and chronic inflammation of the lacrimal gland upregulated multiple inflammasome sensors, caspases 1/4, and interleukins Il1b and Il18. We also found increased IL-1ß maturation in Sjögren's syndrome models compared with healthy control lacrimal glands. Using RNA-seq data of regenerating lacrimal glands, we found that lipogenic genes were upregulated during the resolution of inflammation following acute injury. In chronically inflamed NOD.H2b lacrimal glands, an altered lipid metabolism was associated with disease progression: genes for cholesterol metabolism were upregulated, while genes involved in mitochondrial metabolism and fatty acid synthesis were downregulated, including peroxisome proliferator-activated receptor alpha (PPARα)/sterol regulatory element-binding 1 (SREBP-1)-dependent signaling. We conclude that epithelial cells can promote immune responses by forming inflammasomes, and that sustained inflammasome activation, together with an altered lipid metabolism, are key players of Sjögren's syndrome-like pathogenesis in the NOD.H2b mouse lacrimal gland by promoting epithelial dysfunction and inflammation.

Heterochronic Parabiosis Causes Dacryoadenitis in Young Lacrimal Glands.

Aging is associated with inflammation and oxidative stress in the lacrimal gland (LG). We investigated if heterochronic parabiosis of mice could modulate age-related LG alterations. In both males and females, there were significant increases in total immune infiltration in isochronic aged LGs compared to that in isochronic young LGs. Male heterochronic young LGs were significantly more infiltrated compared to male isochronic young LGs. While both females and males had significant increases in inflammatory and B-cell-related transcripts in isochronic and heterochronic aged LGs compared to levels isochronic and heterochronic young LGs, females had a greater fold expression of some of these transcripts than males. Through flow cytometry, specific subsets of B cells were increased in the male heterochronic aged LGs compared to those in male isochronic aged LGs. Our results indicate that serum soluble factors from young mice were not enough to reverse inflammation and infiltrating immune cells in aged tissues and that there were specific sex-related differences in parabiosis treatment. This suggests that age-related changes in the LG microenvironment/architecture participate in perpetuating inflammation, which is not reversible by exposure to youthful systemic factors. In contrast, male young heterochronic LGs were significantly worse than their isochronic counterparts, suggesting that aged soluble factors can enhance inflammation in the young host. Therapies that aim at improving cellular health may have a stronger impact on improving inflammation and cellular inflammation in LGs than parabiosis.

Modulation of Oxidative Stress and Inflammation in the Aged Lacrimal Gland.

Inflammation and oxidative stress accompany aging. This study investigated the interplay between oxidative stress and inflammation in the lacrimal gland. C57BL/6 mice were used at 2 to 3, 12, and 24 months of age. Nuclear factor erythroid derived-2-related factor 2 (Nrf2)-/- and corresponding wild-type mice were used at 2 to 3 and 12 to 13 months of age. A separate group of 15.5 to 17 months of age C57BL/6 mice received a diet containing an Nrf2 inducer (Oltipraz) for 8 weeks. Aged C57BL/6 lacrimal glands showed significantly greater lymphocytic infiltration, higher levels of MHC II, IFN-γ, IL-1ß, TNF-α, and cathepsin S (Ctss) mRNA transcripts, and greater nitrotyrosine and 4-hydroxynonenal protein. Young Nrf2-/- mice showed an increase in IL-1ß, IFN-γ, MHC II, and Ctss mRNA transcripts compared with young wild-type mice and greater age-related changes at 12 to 13 months of age. Oltipraz diet significantly decreased nitrotyrosine and 4-hydroxynonenal and decreased the expression of IL-1ß and TNF-α mRNA transcripts, while decreasing the frequency of CD45+CD4+ cells in lacrimal glands and significantly increasing conjunctival goblet cell density compared with a standard diet. The findings provide novel insight into the development of chronic, low-grade inflammation and oxidative stress in age-related dry eye. New therapies targeting oxidative stress pathways will be valuable in treating age-related dry eye.

Cathepsin S is a novel target for age-related dry eye.

Cathepsin S (Ctss) is a protease that is proinflammatory on epithelial cells. The purpose of this study was to investigate the role of Ctss in age-related dry eye disease. Ctss-/- mice [in a C57BL/6 (B6) background] of different ages were compared to B6 mice. Ctss activity in tears and lacrimal gland (LG) lysates was measured. The corneal barrier function was investigated in naïve mice or after topical administration of Ctss eye drops 5X/day for two days. Eyes were collected, and conjunctival goblet cell density was measured in PAS-stained sections. Immunoreactivity of the tight junction proteins, ZO-1 and occludin, was investigated in primary human cultured corneal epithelial cells (HCEC) without or with Ctss, with or without a Ctss inhibitor. A significant increase in Ctss activity was observed in the tears and LG lysates in aged B6 compared to young mice. This was accompanied by higher Ctss transcripts and protein expression in LG and spleen. Compared to B6, 12 and 24-month-old Ctss-/- mice did not display age-related corneal barrier disruption and goblet cell loss. Treatment of HCEC with Ctss for 48 h disrupted occludin and ZO-1 immunoreactivity compared to control cells. This was prevented by the Ctss inhibitor LY3000328 or Ctss-heat inactivation. Topical reconstitution of Ctss in Ctss-/- mice for two days disrupted corneal barrier function. Aging on the ocular surface is accompanied by increased expression and activity of the protease Ctss. Our results suggest that cathepsin S modulation might be a novel target for age-related dry eye disease.

A, B, C's of Trk Receptors and Their Ligands in Ocular Repair.

Neurotrophins are a family of closely related secreted proteins that promote differentiation, development, and survival of neurons, which include nerve growth factor (NGF), brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4. All neurotrophins signal through tropomyosin receptor kinases (TrkA, TrkB, and TrkC) which are more selective to NGF, brain-derived neurotrophic factor, and neurotrophin-3, respectively. NGF is the most studied neurotrophin in the ocular surface and a human recombinant NGF has reached clinics, having been approved to treat neurotrophic keratitis. Brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4 are less studied neurotrophins in the ocular surface, even though brain-derived neurotrophic factor is well characterized in glaucoma, retina, and neuroscience. Recently, neurotrophin analogs with panTrk activity and TrkC selectivity have shown promise as novel drugs for treating dry eye disease. In this review, we discuss the biology of the neurotrophin family, its role in corneal homeostasis, and its use in treating ocular surface diseases. There is an unmet need to investigate parenteral neurotrophins and its analogs that activate TrkB and TrkC selectively.

Age-related changes in ocular mucosal tolerance: Lessons learned from gut and respiratory tract immunity.

The ocular surface is the part of the visual system directly exposed to the environment, and it comprises the cornea, the first refractive tissue layer and its surrounding structures. The ocular surface has evolved to keep the cornea smooth and wet, a prerequisite for proper sight, and also protected. To this aim, the ocular surface is a bona fide mucosal niche with an immune system capable of fighting against dangerous pathogens. However, due to the potential harmful effects of uncontrolled inflammation, the ocular surface has several mechanisms to keep the immune response in check. Specifically, the ocular surface is maintained inflammation-free and functional by a particular form of peripheral tolerance known as mucosal tolerance, markedly different from the immune privilege of intraocular structures. Remarkably, conjunctival tolerance is akin to the oral and respiratory tolerance mechanisms found in the gut and airways, respectively. And also similarly, this form of immunoregulation in the eye is affected by ageing just as it is in the digestive and respiratory tracts. With ageing comes an increased prevalence of immune-based ocular surface disorders, which could be related to an age-related impairment of conjunctival tolerance. The purpose of this review was to summarize the present knowledge of ocular mucosal tolerance and how it is affected by the ageing process in the light of the current literature on mucosal immunoregulation of the gut and airways.

Retinoid Regulation of Ocular Surface Innate Inflammation.

Corneal and conjunctival inflammation and dry eye develop in systemic vitamin A deficiency (VAD). The objective of this study was to investigate the lacrimal ocular surface retinoid axis, particularly immunomodulatory effects of retinoic acid (RA) and change in conjunctival myeloid cell number and phenotype in VAD. We discovered that ocular surface epithelial and myeloid cells express retinoid receptors. Both all trans- and 9-cis-RA suppressed production of dry eye relevant inflammatory mediators [interleukin(IL)-1ß, IL-12, regulated upon activation, normal T cell expressed and secreted (RANTES)] by myeloid cells. Systemic VAD was associated with significant goblet cell loss and an increased number of CD45+ immune cells in the conjunctiva. MHCII-CD11b+ classical monocytes were significantly increased in the conjunctiva of VAD C57BL/6 and RXR-α mutated Pinkie strains. RNA seq revealed significantly increased expression of innate immune/inflammatory genes in the Pinkie conjunctiva. These findings indicate that retinoids are essential for maintaining a healthy, well-lubricated ocular surface and have immunomodulatory effects in the conjunctiva that are mediated in part via RXR-α signaling. Perturbation of the homeostatic retinoid axis could potentiate inflammation on the ocular surface.

Mechanisms of Disease in Sjögren Syndrome-New Developments and Directions.

Sjögren Syndrome (SS) is an autoimmune disease that affects the exocrine glands, mainly salivary and lacrimal glands [...].

Parity Attenuates Intraepithelial Corneal Sensory Nerve Loss in Female Mice.

Aging impacts the ocular surface and reduces intraepithelial corneal nerve (ICN) density in male and female mice. Many researchers use retired breeders to study naturally aged female mice. Yet, the impact of parity and the length of time since breeders were retired on age-related changes in the intraepithelial corneal nerves is not known. Here we study 2 month (M) nulliparous (NP) females as well as 9M, 10M, and 11M NP and multiparous (MP) female mice to determine whether parity impacts the age-related decline seen in corneal axon density; 9M male mice are also included in these assessments. After showing that parity attenuates age-related loss in axon density, we also assess the impact of parity on corneal epithelial cell proliferation and find that it impacts cell proliferation and axon density normalized by cell proliferation. Stromal nerve arborization is also impacted by aging with parity enhancing stromal nerves in older mice. qPCR was performed on 20 genes implicated in ICN density using corneal epithelial RNA isolated from 10M NP and MP mice and showed that NGF expression was significantly elevated in MP corneal epithelium. Corneal sensitivity was significantly higher in 9M MP mice compared to NP mice and increased sensitivity in MP mice was accompanied by increased nerve terminals in the apical and middle cell layers. Together, these data show that parity in mice attenuates several aspects of the age-related decline seen on the ocular surface by retaining sensory axons and corneal sensitivity as mice age.

Rapamycin Eyedrops Increased CD4+Foxp3+ Cells and Prevented Goblet Cell Loss in the Aged Ocular Surface.

Dry eye disease (DED), one of the most prevalent conditions among the elderly, is a chronic inflammatory disorder that disrupts tear film stability and causes ocular surface damage. Aged C57BL/6J mice spontaneously develop DED. Rapamycin is a potent immunosuppressant that prolongs the lifespan of several species. Here, we compared the effects of daily instillation of eyedrops containing rapamycin or empty micelles for three months on the aged mice. Tear cytokine/chemokine profile showed a pronounced increase in vascular endothelial cell growth factor-A (VEGF-A) and a trend towards decreased concentration of Interferon gamma (IFN)-γ in rapamycin-treated groups. A significant decrease in inflammatory markers in the lacrimal gland was also evident (IFN-γ, IL-12, CIITA and Ctss); this was accompanied by slightly diminished Unc-51 Like Autophagy Activating Kinase 1 (ULK1) transcripts. In the lacrimal gland and draining lymph nodes, we also observed a significant increase in the CD45+CD4+Foxp3+ cells in the rapamycin-treated mice. More importantly, rapamycin eyedrops increased conjunctival goblet cell density and area compared to the empty micelles. Taken together, evidence from these studies indicates that topical rapamycin has therapeutic efficacy for age-associated ocular surface inflammation and goblet cell loss and opens the venue for new investigations on its role in the aging process of the eye.

IL-27 signaling deficiency develops Th17-enhanced Th2-dominant inflammation in murine allergic conjunctivitis model.

BACKGROUND: While most studies focus on pro-allergic cytokines, the protective role of immunosuppressive cytokines in allergic inflammation is not well elucidated. This study was to explore a novel anti-inflammatory role and cellular/molecular mechanism of IL-27 in allergic inflammation. METHODS: A murine model of experimental allergic conjunctivitis (EAC) was induced in BALB/c, C57BL/6 or IL-27Rα-deficient (WSX-1-/- ) mice by short ragweed pollen, with untreated or PBS-treated mice as controls. The serum, eyeballs, conjunctiva, cervical lymph nodes (CLNs) were used for study. Gene expression was determined by RT-qPCR, and protein production and activation were evaluated by immunostaining, ELISA and Western blotting. RESULTS: Typical allergic manifestations and stimulated thymic stromal lymphopoietin (TSLP) signaling and Th2 responses were observed in ocular surface of EAC models in BALB/c and C57BL/6 mice. The decrease of IL-27 at mRNA (IL-27/EBI3) and protein levels were detected in serum, conjunctiva and CLN, as evaluated by RT-qPCR, immunofluorescent staining, ELISA and Western blotting. EAC induced in WSX-1-/- mice showed aggravated allergic signs with higher TSLP-driven Th2-dominant inflammation, accompanied by stimulated Th17 responses, including IL-17A, IL-17F, and transcription factor RORγt. In contrast, Th1 cytokine IFNγ and Treg marker IL-10, with their respective transcription factors T-bet and foxp3, were largely suppressed. Interestingly, imbalanced activation between reduced phosphor (P)-STAT1 and stimulated P-STAT6 were revealed in EAC, especially WSX-1-/- -EAC mice. CONCLUSION: These findings demonstrated a natural protective mechanism by IL-27, of which signaling deficiency develops a Th17-type hyperresponse that further aggravates Th2-dominant allergic inflammation.

Goblet cell-produced retinoic acid suppresses CD86 expression and IL-12 production in bone marrow-derived cells.

Conjunctival goblet cell loss in ocular surface diseases is accompanied by increased number of interleukin-12 (IL-12)-producing antigen-presenting cells (APCs) and increased interferon-γ (IFN-γ) expression. This study tested the hypothesis that mouse conjunctival goblet cells produce biologically active retinoic acid (RA) that suppresses CD86 expression and IL-12 production by myeloid cells. We found that conditioned media from cultured conjunctival goblet cells (CjCM) suppressed stimulated CD86 expression, NF-κB p65 activation and IL-12 and IFN-γ production in unstimulated and lipopolysaccharide-stimulated cultured bone marrow-derived cells (BMDCs) containing a mixed population of APCs. Goblet cell-conditioned, ovalbumin-loaded APCs suppressed IFN-γ production and increased IL-13 production in co-cultured OTII cells. The goblet cell suppressive activity is due in part to their ability to synthesize RA from retinol. Conjunctival goblet cells had greater expression of aldehyde dehydrogenases Aldh1a1 and a3 and ALDEFLUOR activity than cornea epithelium lacking goblet cells. The conditioning activity was lost in goblet cells treated with an ALDH inhibitor, and a retinoid receptor alpha antagonist blocked the suppressive effects of CjCM on IL-12 production. Similar to RA, CjCM increased expression of suppressor of cytokine signaling 3 (SOCS3) in BMDCs. SOCS3 silencing reversed the IL-12-suppressive effects of CjCM. Our findings indicate that conjunctival goblet cells are capable of synthesizing RA from retinol secreted by the lacrimal gland into tears that can condition APCs. Evidence suggests goblet cell RA may function in maintaining conjunctival immune tolerance and loss of conjunctival goblet cells may contribute to increased Th1 priming in dry eye.

Topical cyclosporine A therapy for dry eye syndrome.

BACKGROUND: Topical cyclosporine A (also known as ciclosporin A) (CsA) is an anti-inflammatory that has been widely used to treat inflammatory ocular surface diseases. Two CsA eyedrops have been approved by US Food and Drug Administration for managing dry eye: Restasis (CsA 0.05%, Allergan Inc, Irvine, CA, USA), approved in 2002, and Cequa (CsA 0.09%, Sun Pharma, Cranbury, NJ, USA), approved in 2018. Numerous clinical trials have been performed to assess the effectiveness and safety of CsA for dry eye; however, there is no universal consensus with regard to its effect. OBJECTIVES: To assess the effectiveness and safety of topical CsA in the treatment of dry eye. SEARCH METHODS: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2018, Issue 2); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Sciences Literature Database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 16 February 2018. SELECTION CRITERIA: We included randomized controlled trials (RCTs) of people with dry eye regardless of age, sex, severity, etiology, or classification of dry eye. We included RCTs in which different concentrations of topical CsA were compared with one another or with artificial tears, placebo, or vehicle. We also included RCTs in which CsA in combination with artificial tears was compared to artificial tears alone. DATA COLLECTION AND ANALYSIS: We followed the standard Cochrane methodology and assessed the certainty of the evidence using GRADE. MAIN RESULTS: We included 30 RCTs (4009 participants) with follow-up periods ranging from 6 weeks to 12 months. We studied dry eye of various severity and underlying causes. The interventions investigated also varied across RCTs: CsA versus artificial tears; CsA with artificial tears versus artificial tears alone; and in some studies, more than one concentration of CsA. Artificial tears were used as adjunctive to study medication in all but five trials. Almost all trials had deficiencies in the reporting of results (e.g. reporting P values or direction only), precluding the calculation of between-group estimates of effect or meta-analysis.Eighteen trials compared topical CsA 0.05% plus artificial tears versus vehicle plus artificial tears or artificial tears alone. One trial reported subjective symptoms of dry eye at 6 months and the results were in favor of CsA (mean difference (MD) -4.80, 95% confidence interval (CI) -6.41 to -3.19; low-certainty evidence). Two trials reported MD in ocular surface dye staining at 6 months, but the results were inconsistent in these two trials (MD -0.35, 95% CI -0.69 to -0.01 in one and MD 0.58, 95% CI 0.06 to 1.10 in the other; low-certainty evidence). Four trials reported MD in Schirmer test scores at 6 months and the estimates ranged from -4.05 (95% CI -6.67 to -1.73) to 3.26 (95% CI -1.52 to 5.00) (low-certainty evidence). Three trials reported risk ratio (RR) of improved Schirmer test scores at 6 months; estimates ranged from 0.98 (95% CI 0.83 to 1.17) to 3.50 (95% CI 2.09 to 5.85) (low-certainty evidence). Four trials reported MD in tear film stability measured by tear break-up time at 6 months and the estimates ranged from -1.98 (95% CI -3.59 to -0.37) to 1.90 (95% CI 1.44 to 2.36) (low-certainty evidence). Three trials reported RR of improved tear break-up time at 6 months and the estimates ranged from 0.90 (95% CI 0.77 to 1.04) to 4.00 (95% CI 2.25 to 7.12) (low-certainty evidence). Three trials reported frequency of artificial tear usage at 6 months without providing any estimates of effect; the direction of effect seem to be in favor of CsA (low-certainty evidence). Because of incomplete reporting of the results data or considerable statistical heterogeneity, we were only able to perform a meta-analysis on mean conjunctival goblet cell density. Mean conjunctival goblet cell density in the CsA treated group may be greater than that in the control group at the end of follow-up at four and 12 months (MD 22.5 cells per unit, 95% CI 16.3 to 28.8; low-certainty evidence). All but two trials reported adverse events that included burning and stinging. Participants treated with CsA may be more likely to have treatment-related adverse events than those who treated with vehicle (RR 1.33, 95% CI 1.00 to 1.78; low-certainty evidence).Other comparisons evaluated were CsA 0.05% plus artificial tears versus higher concentrations of CsA plus artificial tears (4 trials); CsA 0.05% versus placebo or vehicle (4 trials); CsA 0.1% plus artificial tears versus placebo or vehicle plus artificial tears (2 trials);CsA 0.1% cationic emulsion plus artificial tears versus vehicle plus artificial tears (2 trials); CsA 1% plus artificial tears versus placebo plus artificial tears (3 trials); and CsA 2% plus artificial tears versus placebo plus artificial tears (3 trials). Almost all of these trials reported P value or direction of effect only (mostly in favor of CsA), precluding calculation of between-group effect estimates or meta-analyses. AUTHORS' CONCLUSIONS: Despite the widespread use of topical CsA to treat dry eye, we found that evidence on the effect of CsA on ocular discomfort and ocular surface and tear film parameters such as corneal fluorescein staining, Schirmer's test, and TBUT is inconsistent and sometimes may not be different from vehicle or artificial tears for the time periods reported in the trials. There may be an increase in non-serious, treatment-related adverse effects (particularly burning) in the CsA group. Topical CsA may increase the number of conjunctival goblet cells. However, current evidence does not support that improvements in conjunctival mucus production (through increased conjunctival goblet cells) translate to improved symptoms or ocular surface and tear film parameters. All published trials were short term and did not assess whether CsA has longer-term disease-modifying effects. Well-planned, long-term, large clinical trials are needed to better assess CsA on long-term dry eye-modifying effects. A core outcome set, which ideally includes both biomarkers and patient-reported outcomes in the field of dry eye, is needed.

Protective role of commensal bacteria in Sjögren Syndrome.

CD25 knock-out (CD25KO) mice spontaneously develop Sjögren Syndrome (SS)-like inflammation. We investigated the role of commensal bacteria by comparing CD25KO mice housed in conventional or germ-free conditions. Germ-free CD25KO mice have greater corneal barrier dysfunction, lower goblet cell density, increased total lymphocytic infiltration score, increased expression of IFN-γ, IL-12 and higher a frequency of CD4+IFN-γ+ cells than conventional mice. CD4+ T cells isolated from female germ-free CD25KO mice adoptively transferred to naive immunodeficient RAG1KO recipients caused more severe Sjögren-like disease than CD4+ T cells transferred from conventional CD25KO mice. Fecal transplant in germ-free CD25KO mice reversed the spontaneous dry eye phenotype and decreased the generation of pathogenic CD4+IFN-γ+ cells. Our studies indicate that lack of commensal bacteria accelerates the onset and severity of dacryoadenitis and generates autoreactive CD4+T cells with greater pathogenicity in the CD25KO model, suggesting that the commensal bacteria or their metabolites products have immunoregulatory properties that protect exocrine glands in the CD25KO SS model.

Reduced intraepithelial corneal nerve density and sensitivity accompany desiccating stress and aging in C57BL/6 mice.

Dry Eye disease causes discomfort and pain in millions of patients. Using a mouse acute desiccating stress (DS) model we show that DS induces a reduction in intraepithelial corneal nerve (ICN) density, corneal sensitivity, and apical extension of the intraepithelial nerve terminals (INTs) that branch from the subbasal nerves (SBNs). Topical application of 0.02% Mitomycin C (MMC) or vehicle alone has no impact on the overall loss of axon density due to acute DS. Chronic dry eye, which develops progressively as C57BL/6 mice age, is accompanied by significant loss of the ICNs and corneal sensitivity between 2 and 24 months of age. QPCR studies show that mRNAs for several proteins that regulate axon growth and extension are reduced in corneal epithelial cells by 24 months of age but those that regulate phagocytosis and autophagy are not altered. Taken together, these data demonstrate that dry eye disease is accompanied by alterations in intraepithelial sensory nerve morphology and function and by reduced expression in corneal epithelial cells of mRNAs encoding genes mediating axon extension. Précis: Acute and chronic mouse models of dry eye disease are used to evaluate the pathologic effects of dry eye on the intraepithelial corneal nerves (ICNs) and corneal epithelial cells. Data show reduced numbers of sensory nerves and alterations in nerve morphology, sensitivity, corneal epithelial cell proliferation, and expression of mRNAs for proteins mediating axon extension accompany the pathology induced by dry eye.

Severity of Sjögren's Syndrome Keratoconjunctivitis Sicca Increases with Increased Percentage of Conjunctival Antigen-Presenting Cells.

This study investigated the relationship between clinical severity and percentage of conjunctival antigen-presenting cells (APCs) in Sjögren's syndrome (SS)-associated keratoconjunctivitis sicca (KCS). KCS clinical severity was based on symptom severity, tear volume, tear break-up time, and ocular surface dye staining. Conjunctival goblet cell density (GCD) was measured in periodic acid Schiff (PAS)-stained membranes. Conjunctival cells obtained by impression cytology were used for flow cytometry to measure percentages of CD45⁺HLA-DR⁺ APCs and mature CD11c⁺CD86⁺ dendritic cells (DCs). Compared to normal conjunctiva, the percentages of HLA-DR⁺ and CD11c⁺CD86⁺ cells were higher in the conjunctiva of the KCS group (p < 0.05). The percentage of CD45⁺HLA-DR⁺ cells positively correlated with clinical severity (r = 0.71, p < 0.05) and negatively correlated with GCD (r = -0.61, p < 0.05). Clinical severity also negatively correlated with GCD (r = -0.54, p < 0.05). These findings indicate that a higher percentage of APCs and mature DCs in the conjunctiva is associated with more severe KCS in SS. These APCs may contribute to the generation of the pathogenic Th1 cells that cause goblet cell loss in KCS.

Reduced Corneal Innervation in the CD25 Null Model of Sjögren Syndrome.

Decreased corneal innervation is frequent in patients with Sjögren Syndrome (SS). To investigate the density and morphology of the intraepithelial corneal nerves (ICNs), corneal sensitivity, epithelial cell proliferation, and changes in mRNA expression of genes that are involved in autophagy and axon targeting and extension were assessed using the IL-2 receptor alpha chain (CD25 null) model of SS. ICN density and thickness in male and female wt and CD25 null corneas were assessed at 4, 6, 8, and 10/11 wk of age. Cell proliferation was assessed using ki67. Mechanical corneal sensitivity was measured. Quantitative PCR was performed to quantify expression of beclin 1, LC3, Lamp-1, Lamp-2, CXCL-1, BDNF, NTN1, DCC, Unc5b1, Efna4, Efna5, Rgma, and p21 in corneal epithelial mRNA. A significant reduction in corneal axon density and mechanical sensitivity were observed, which negatively correlate with epithelial cell proliferation. CD25 null mice have increased expression of genes regulating autophagy (beclin-1, LC3, LAMP-1, LAMP-2, CXCL1, and BDNF) and no change was observed in genes that were related to axonal targeting and extension. Decreased anatomic corneal innervation in the CD25 null SS model is accompanied by reduced corneal sensitivity, increased corneal epithelial cell proliferation, and increased expression of genes regulating phagocytosis and autophagy.