Corneal Lymphatics: Role in Ocular Inflammation as Inducer and Responder of Adaptive Immunity

The normal cornea is devoid of lymphatic and blood vessels, thus suppressing both the afferent (lymphatic) and efferent (vascular) arms of the immune response–contributing to its ‘immune privilege’. Inflammation, however, negates this unique ‘immune’ and ‘angiogenic’ privilege of the cornea. Abnormal blood vessel growth from pre-existing limbal vessels into the cornea has been studied for many years, but it is only recently that the significance of new lymphatic vessels (lymphangiogenesis) in ocular inflammatory diseases has been demonstrated. Whereas blood vessels in inflamed ocular surface provide a route of entry for immune effector cells to the cornea, lymphatics facilitate the exit of antigen-presenting cells and antigenic material from the cornea to regional lymph nodes, thus promoting induction of adaptive immune response. This review summarizes the current evidence for lymphangiogenesis in the cornea, and describes its molecular mediators; and discusses the interface between corneal lymphangiogenesis and adaptive immunity. Furthermore, the pathophysiologic implications of corneal lymphangiogenesis in the setting of allo- and autoimmune-mediated corneal inflammation are discussed

Expression of the chemokine decoy receptor D6 mediates dendritic cell function and promotes corneal allograft rejection

Purpose To identify the role of chemokine receptor 6 (D6) expression by dendritic cells (DCs) and its role in corneal transplant immunity. Methods: Flow cytometry analysis was used to assess the expression level of the D6 chemokine receptor in different leukocyte populations and DC maturation following lipopolysaccharides (LPS) stimulation of bone marrow–derived DCs isolated from wild-type (WT) or D6−/− mice (C57BL/6 background). Mixed-lymphocyte reactions and delayed-type hypersensitivity assays were performed with bone marrow–derived DCs from WT or D6−/− mice to evaluate T-cell alloreactivity. Adoptive transfer experiments with T cells from WT or D6−/− hosts with BALB/c corneal allografts were performed. Graft opacity was assessed over an 8-week period, and graft survival was plotted using Kaplan–Meier survival curves. Results: Expression of the D6 chemokine receptor was significantly higher in DCs compared to other leukocyte subpopulations, including neutrophils, lymphocytes, and monocytes/macrophages. LPS challenge of D6−/− bone marrow–derived DCs elicited significantly lower levels of major histocompatibility complex II and costimulatory molecules (CD40, CD80, and CD86) compared to WT bone marrow–derived DCs, indicating the role of the D6 chemokine receptor in DC maturation. Further, DCs isolated from D6−/− mice induced less T-cell proliferation (p≤0.001) and interferon-gamma production in T cells of draining lymph nodes compared to WT mice following corneal transplantation (p≤0.001). Moreover, adoptively transferred T cells from D6−/− corneal transplanted mice to WT mice led to impaired graft rejection, compared to the hosts that received T cells from the WT transplanted mice. Conclusions: We demonstrated D6 chemokine receptor expression by DCs and identified its critical function in multiple aspects of DC biology, including maturation and consequent elicitation of alloreactive T-cell responses that are responsible for corneal allograft rejection

Chronic Dry Eye Disease is Principally Mediated by Effector Memory Th17 Cells

Recent experimental and clinical data suggest that there is a link between dry eye disease (DED) and T cell-mediated immunity. However, whether these immune responses are a consequence or cause of ocular surface inflammation remains to be determined. Thus far, only models of acute DED have been used to derive experimental data. This is in contrast to clinical DED which usually presents as a chronic disease. In the present study, using a murine model of chronic DED, it was established that the chronic phase of the disease is accompanied by Th17 responses at the ocular surface, and that a significant memory T cell population can be recovered from chronic DED. This memory response is predominantly mediated by Th17 cells. Moreover, adoptive transfer of this memory T cell population was shown to induce more severe and rapidly progressing DED than did the adoptive transfer of its effector or naïve counterparts. Not only do these results clearly demonstrate that effector memory Th17 cells are primarily responsible for maintaining the chronic and relapsing course of DED, but they also highlight a potentially novel therapeutic strategy for targeting memory immune responses in patients with DED

Neutrophil L-plastin controls ocular paucibacteriality and susceptibility to keratitis

Why ocular mucosa is paucibacterial is unknown. Many different mechanisms have been suggested but the comprehensive experimental studies are sparse. We found that a deficiency in L-plastin (LCP1), an actin bundling protein, resulted in an ocular commensal overgrowth, characterized with increased presence of conjunctiva

Comparative evaluation of hypofractionated radiotherapy versus conventionally fractionated radiotherapy for patients with intermediate and high risk prostate cancer

Background: The purpose of this study was to comparatively evaluate an efficacy and toxicity profile of hypofractionated radiotherapy (67.5 Gy in 25 fractions) to conventionally fractionated radiotherapy (78 Gy in 39 fractions) in prostate cancer patients with intermediate and high-risk disease. Materials and methods: From January 2015 to December 2018, 168 patients were randomized to hypofractionated radiation treatment and conventional fractionated radiation treatment schedules of volumetric modulated arc therapy (VMAT) to the prostate and seminal vesicles. All the patients also received androgen deprivation therapy (ADT) and radiation therapy started after ADT. Results: The median (range) follow-up was 51 (31–63) and 53 (33–64) months in the hypofractionated and conventionally fractionated regimes, respectively. The 3-year biochemical no evidence of disease (bNED) rates were 86.9% and 73.8% in the hypofractionated and conventionally fractionated groups, respectively (p = 0.032, significant). The 3-year bNED rates in patients at a high risk [i.e., pretreatment prostate-specific antigen (PSA) > 20 ng/mL, Gleason score ≥ 8, or T ≥ 2 c], were 87.9% and 73.5% (p = 0.007, significant) in the hypofractionated and conventionally fractionated radiotherapy groups, respectively. No statistically significant difference was found for late toxicity between the two groups, with 3-year grade 2 gastrointestinal toxicity rates of 19% and 16.7% and 3-year grade 2 genitourinary toxicity rates of 15.5% and 11.9% in the hypofractionated and conventionally fractionated radiotherapy groups, respectively. Conclusion: Hypofractionated schedule is superior to the conventional fractionation schedule of radiation treatment in terms of bNED in intermediate and high grade prostate cancer patients. Also, the late toxicity is found to be equivalent between the two treatment groups

Restoration of Corneal Transparency by Mesenchymal Stem Cells

Summary Transparency of the cornea is indispensable for optimal vision. Ocular trauma is a leading cause of corneal opacity, leading to 25 million cases of blindness annually. Recently, mesenchymal stem cells (MSCs) have gained prominence due to their inflammation-suppressing and tissue repair functions. Here, we investigate the potential of MSCs to restore corneal transparency following ocular injury. Using an in vivo mouse model of ocular injury, we report that MSCs have the capacity to restore corneal transparency by secreting high levels of hepatocyte growth factor (HGF). Interestingly, our data also show that HGF alone can restore corneal transparency, an observation that has translational implications for the development of HGF-based therapy

FORMULATION AND EVALUATION OF BILAYERED FLOATING TABLET OF DILTIAZEM DRUG

Aim of study was to develop bilayered floating drug delivery for treatment of hypertension by delivering loading and maintenance dose for fast achievement of peak plasma concentration and maintaining the same respectively. The prepared drug loaded bilayered floating tablets were evaluated for pre and post compression parameters. Stability study of the promising formulation was also performed. The tablets were prepared by direct compression method. The loading dose was delivered in the form of immediate release layer prepared by different super-disintegrations and maintenance dose was delivered through sustained release layer prepared by using polymers like HPMC K15M and Carbopol 934P. Both the immediate release layer and sustained release layers were separately optimized and then combined to optimize the bilayered floating tablets. No interactions were found between drug and excipients. Formulation containing crosscarmellose sodium shows immediate drug release. Formulation Containing HPMC K15M shows sustained release action and bilayered formulations FB7 shows releases up to 12 hours with good buoyancy and total floating time. All the Bilayered floating formulations buoyant up to 12 hrs. Bilayered floating tablets with release characteristics offer critical advantages such as, site specificity with improved absorption and efficacy. This technology can be inculcated to various medicaments which have stomach as the major site of absorption. Key words: Diltiazem, Bilayered floating tablet, sustain release table

Graft Site Microenvironment Determines Dendritic Cell Trafficking Through the CCR7-CCL19/21 Axis

Purpose The graft site microenvironment has a profound effect on alloimmunity and graft survival. We aimed to study the kinetics and phenotype of trafficking antigen-presenting cells (APC) to the draining lymph nodes (DLNs) in a mouse model of corneal transplantation, and to evaluate the homing mechanisms through which graft site inflammation controls APC trafficking. Methods: Allogeneic donor corneas were transplanted onto inflamed or quiescent graft beds. Host- (YAe+) and donor (CD45.1+ or eGFP+)-derived APCs were analyzed by flow cytometry. Protein and mRNA expression of the CC chemokine receptor (CCR)7 ligands CCL19 and CCL21 were assessed using ELISA and Real-Time qPCR, respectively. Transwell migration assay was performed to assess the effect of DLNs isolated from hosts with inflamed graft beds on mature bone marrow–derived dendritic cells (BMDCs). Results: We found that inflamed graft sites greatly promote the trafficking of both recipient- and graft-derived APCs, in particular mature CCR7+ CD11c+ dendritic cells (DC). CCL19 and CCL21 were expressed at significantly higher levels in the DLNs of recipients with inflamed graft beds. The supernatant of DLNs from recipients with inflamed graft beds induced a marked increase in mature DC migration compared with supernatant from recipients with quiescent graft beds in a transwell assay. This effect was abolished by neutralizing CCL19 or CCL21. These data suggest that graft site inflammation increases the expression of CCR7 ligands in the DLNs, which promote mature DC homing and allorejection. Conclusions: We conclude that the graft site microenvironment plays a critical role in alloimmunity by determining DC trafficking through the CCR7-CCL19/21 axis