Autoimmune uveitis: clinical, pathogenetic, and therapeutic features

Microglial mediators in autoimmune Uveitis: Bridging neuroprotection and neurotoxicity

Autoimmune uveitis, a severe inflammatory condition of the eye, poses significant challenges due to its complex pathophysiology and the critical balance between protective and detrimental immune responses. Central to this balance are microglia, the resident immune cells of the central nervous system, whose roles in autoimmune uveitis are multifaceted and dynamic. This review article delves into the dual nature of microglial functions, oscillating between neuroprotective and neurotoxic outcomes in the context of autoimmune uveitis. Initially, we explore the fundamental aspects of microglia, including their activation states and basic functions, setting the stage for a deeper understanding of their involvement in autoimmune uveitis. The review then navigates through the intricate mechanisms by which microglia contribute to disease onset and progression, highlighting both their protective actions in immune regulation and tissue repair, and their shift towards a pro-inflammatory, neurotoxic profile. Special emphasis is placed on the detailed pathways and cellular interactions underpinning these dual roles. Additionally, the review examines the potential of microglial markers as diagnostic and prognostic indicators, offering insights into their clinical relevance. The article culminates in discussing future research directions, and the ongoing challenges in translating these findings into effective clinical applications. By providing a comprehensive overview of microglial mechanisms in autoimmune uveitis, this review underscores the critical balance of microglial activities and its implications for disease management and therapy development.

Potential in exosome-based targeted nano-drugs and delivery vehicles for posterior ocular disease treatment: from barriers to therapeutic application

Posterior ocular disease, a disease that accounts for 55% of all ocular diseases, can contribute to permanent vision loss if left without treatment. Due to the special structure of the eye, various obstacles make it difficult for drugs to reach lesions in the posterior ocular segment. Therefore, the development of highly permeable targeted drugs and delivery systems is particularly important. Exosomes are a class of extracellular vesicles at 30-150 nm, which are secreted by various cells, tissues, and body fluids. They carry various signaling molecules, thus endowing them with certain physiological functions. In this review, we describe the ocular barriers and the biogenesis, isolation, and engineering of exosomes, as exosomes not only have pharmacological effects but also are good nanocarriers with targeted properties. Moreover, their biocompatibility and immunogenicity are better than synthetic nanocarriers. Most importantly, they may have the ability to pass through the blood-eye barrier. Thus, they may be developed as both targeted nano-drugs and nano-delivery vehicles for the treatment of posterior ocular diseases. We focus on the current status and potential application of exosomes as targeted nano-drugs and nano-delivery vehicles in posterior ocular diseases.

Enhanced immunosuppressive capability of mesenchymal stem cell-derived small extracellular vesicles with high expression of CD73 in experimental autoimmune uveitis

BACKGROUND

Autoimmune uveitis is an inflammatory disease triggered by an aberrant immune response. Mesenchymal stem cell-derived small extracellular vesicles (MSC-sEVs) are emerging as potential therapeutic agents for this condition. CD73, an ectoenzyme present on MSC-sEVs, is involved in mitigating inflammation by converting extracellular adenosine monophosphate into adenosine. We hypothesize that the inhibitory effect of MSC-sEVs on experimental autoimmune uveitis (EAU) could be partially attributed to the surface expression of CD73.

METHODS

To investigate novel therapeutic approaches for autoimmune uveitis, we performed lentiviral transduction to overexpress CD73 on the surface of MSC-sEVs, yielding CD73-enriched MSC-sEVs (sEVs-CD73). Mice with interphotoreceptor retinoid-binding protein (IRBP)-induced EAU were grouped randomly and treated with 50 µg MSC-sEVs, vector infected MSC-sEVs, sEVs-CD73 or PBS via single tail vein injection. We evaluated the clinical and histological features of the induced mice and analyzed the proportion and functional capabilities of T helper cells. Furthermore, T-cells were co-cultured with various MSC-sEVs in vitro, and we quantified the resulting inflammatory response to assess the potential therapeutic benefits of sEVs-CD73.

RESULTS

Compared to MSC-sEVs, sEVs-CD73 significantly alleviates EAU, leading to reduced inflammation and diminished tissue damage. Treatment with sEVs-CD73 results in a decreased proportion of Th1 cells in the spleen, draining lymph nodes, and eyes, accompanied by an increased proportion of regulatory T-cells (Treg cells). In vitro assays further reveal that sEVs-CD73 inhibits T-cell proliferation, suppresses Th1 cells differentiation, and enhances Treg cells proportion.

CONCLUSION

Over-expression of CD73 on MSC-sEVs enhances their immunosuppressive effects in EAU, indicating that sEVs-CD73 has the potential as an efficient immunotherapeutic agent for autoimmune uveitis.

Lipid profile alterations in non-infectious uveitis: correlation with quantitative optical coherence tomography angiography parameters

BACKGROUND/AIMS

Lipid profiles have been changed in numerous chronic conditions. The impact of uveitis on lipid metabolism remains unclear.

METHODS

This is a cross-sectional study included 416 patients with non-infectious uveitis (NIU) and 416 healthy subjects. Standard techniques were used to measure total cholesterol (TC), triglycerides (TG), high-density lipoprotein-cholesterol (HDLc), low-density lipoprotein-cholesterol (LDLc) levels. Quantitative optical coherence tomography angiography (OCTA) parameters were obtained from 500 eyes in each group. Correlation analysis examined the relationship between lipid profile and OCTA parameters.

RESULTS

Patients with NIU exhibited significantly elevated TC, TG and LDLc levels compared with controls (p=0.003; p<0.001; p<0.001, respectively). Subgroup analysis revealed that HDLc was significantly lower in Behçet's disease (p=0.024) compared with controls. Vascular density (VD) in the superficial capillary plexus (SCP), deep capillary plexus (DCP), choriocapillaris and optic disk were significantly decreased in NIU eyes (p<0.05, respectively) compared with controls. HDLc exhibited a significant negative correlation with VDs in the whole and parafovea SCP (r=-0.489, p=0.008; r=-0.480, p=0.0026, respectively), while LDLc showed a significant positive correlation with VDs in the whole and parafovea DCP in NIU patients (r=0.576, p=0.032; r=0.267, p=0.034, respectively).

CONCLUSIONS

The lipid profile is altered in NIU, and there are correlations between HDLc and LDLc levels and VD as measured by OCTA. Lipid profile analysis may offer valuable insights into evaluating vascular and metabolic aspects of NIU.

YY1 Lactylation Aggravates Autoimmune Uveitis by Enhancing Microglial Functions via Inflammatory Genes

Activated microglia in the retina are essential for the development of autoimmune uveitis. Yin-Yang 1 (YY1) is an important transcription factor that participates in multiple inflammatory and immune-mediated diseases. Here, an increased YY1 lactylation in retinal microglia within in the experimental autoimmune uveitis (EAU) group is observed. YY1 lactylation contributed to boosting microglial activation and promoting their proliferation and migration abilities. Inhibition of lactylation suppressed microglial activation and attenuated inflammation in EAU. Mechanistically, cleavage under targets & tagmentation （CUT&Tag） analysis revealed that YY1 lactylation promoted microglial activation by regulating the transcription of a set of inflammatory genes, including STAT3, CCL5, IRF1, IDO1, and SEMA4D. In addition, p300 is identified as the writer of YY1 lactylation. Inhibition of p300 decreased YY1 lactylation and suppressed microglial inflammation in vivo and in vitro. Collectively, the results showed that YY1 lactylation promoted microglial dysfunction in autoimmune uveitis by upregulating inflammatory cytokine secretion and boosting cell migration and proliferation. Therapeutic effects can be achieved by targeting the lactate/p300/YY1 lactylation/inflammatory genes axis.

The Role of Complement System's C3 and C4 Fractions in the Pathogenesis of Uveitis

PURPOSE

To study the role of the complement system's C3 and C4 fractions in the pathogenesis of different types of uveitis.

METHODS

A prospective case-control study. 118 patients were enrolled. The control group comprised 60 patients who were otherwise healthy people undergoing cataract or pterygium surgery, whereas the uveitis patients group consisted of 58 people. The levels of C3 and C4 fractions in the blood and in the aqueous humor for both groups were evaluated and compared.

RESULTS

No statistically significant differences were found in the levels of the C3 and C4 fractions in the blood between the groups. However, a statistically significant difference was observed in the levels of C3 and C4 in the aqueous humor between the case and control groups, as C3 and C4 fractions were not detected in the control group. The analysis of the mean gradient between the C4 levels in the blood samples and in the aqueous samples did not reveal a statistically significant difference between the case and control groups. However, upon performing an analogous mean gradient analysis of C3 levels, a statistically significant elevation in the value of the mean gradient was observed in the case group as compared to the control group.

CONCLUSION

Our findings are in line with our initial hypothesis, that the complement system's C3 and C4 fractions may have a role in the pathogenesis of uveitis.

MiR-223-3p attenuates M1 macrophage polarization via suppressing the Notch signaling pathway and NLRP3-mediated pyroptosis in experimental autoimmune uveitis

Autoimmune uveitis is an intraocular inflammatory disease with a high blindness rate in developed countries such as the United States. It is pressing to comprehend the pathogenesis of autoimmune uveitis and develop novel schemes for its treatment. In the present research, we demonstrated that the Notch signaling pathway was activated, and the level of miR-223-3p was significantly reduced in rats with experimental autoimmune uveitis (EAU) compared with the level of normal rats. To investigate the relationship between miR-223-3p and Notch signaling, EAU rats received miR-223-3p-carrying lentivirus, miR-223-3p vector-carrying lentivirus (miR-223-3p-N), and γ-secretase inhibitor (DAPT), respectively. The results of Q-PCR, immunological experiments, and flow cytometry analysis all support the hypothesis that both miR-223-3p and DAPT, a Notch signaling pathway inhibitor, had similar inhibitory effects on the EAU pathological process. That is to say, they could both inhibit the activation of the Notch signaling pathway via modulating recombination signal binding protein-Jκ (RBPJ) to restore the polarization imbalance of M/M2 macrophages in EAU rats. In addition, miR-223-3p could also inhibit NLRP3 inflammasome activation and inflammasome-induced pyroptosis in ocular tissues. Taken together, our findings indicate that miR-223-3p serves as an important regulator in M1 macrophage polarization and pyroptosis, thereby alleviating the inflammatory response in uveitis.

Etiological Diagnosis of Uveitis: Contribution of the of the Extra-Ophthalmological Clinical Examination

PURPOSE

Determining uveitis etiology is a challenge. It is based primarily on demographic data and the characteristics of eye examination. It is not clear to what extent extraocular physical signs contribute to elucidating the etiology. This study aimed to establish the contribution of the clinical extra-ophthalmological features for the assessment of the underlying etiology of uveitis.

METHODS

We retrospectively reviewed 1307 patients with uveitis referred to our tertiary center between 2003 and 2021. Uveitis was classified according to the Standardization of Uveitis Nomenclature. Clinical features were collected at diagnosis by internists before the etiological diagnosis was made. The main outcome description was the contribution of clinical features.

RESULTS

Clinical extra-ophthalmological features contributed to the assessment of the underlying etiology of uveitis in 363 (27.8%) patients. The joint and the skin examinations were the most useful for etiological investigations, respectively in 12.3% and 11.8% of patients. Five etiologies of uveitis accounted for 80% of the cases: sarcoidosis, HLA-B27-related uveitis, Behçet's disease, multiple sclerosis, and Vogt-Koyanagi-Harada disease. Clinical extra-ophthalmological features were particularly important in the etiological diagnosis of acute bilateral anterior uveitis and panuveitis.

CONCLUSION

This study suggests that clinical extra-ophthalmological features are essential for the etiological diagnosis of uveitis in more than a quarter of patients. It demonstrates once again the value of collaboration between ophthalmologists and other specialists experienced in performing extra-ophthalmological clinical examinations, particularly in patients with acute bilateral anterior uveitis and panuveitis.

Advances in development of exosomes for ophthalmic therapeutics

Exosomes contain multiple bioactive molecules and maintain the connection between cells. Recent advances in exosome-based therapeutics have witnessed unprecedented opportunities in treating ophthalmic diseases, including traumatic diseases, autoimmune diseases, chorioretinal diseases and others. Utilization of exosomes as delivery vectors to encapsulate both drugs and therapeutic genes could yield higher efficacy and avoid the unnecessary immune responses. However, exosome-based therapies also come with some potential ocular risks. In this review, we first present a general introduction to exosomes. Then we provide an overview of available applications and discuss their potential risks. Moreover, we review recently reported exosomes as delivery vectors for ophthalmic diseases. Finally, we put forward future perspectives to grapple with its translation and underlying issues.

Biogenesis, Composition and Potential Therapeutic Applications of Mesenchymal Stem Cells Derived Exosomes in Various Diseases

Exosomes are nanovesicles with a wide range of chemical compositions used in many different applications. Mesenchymal stem cell-derived exosomes (MSCs-EXOs) are spherical vesicles that have been shown to mediate tissue regeneration in a variety of diseases, including neurological, autoimmune and inflammatory, cancer, ischemic heart disease, lung injury, and liver fibrosis. They can modulate the immune response by interacting with immune effector cells due to the presence of anti-inflammatory compounds and are involved in intercellular communication through various types of cargo. MSCs-EXOs exhibit cytokine storm-mitigating properties in response to COVID-19. This review discussed the potential function of MSCs-EXOs in a variety of diseases including neurological, notably epileptic encephalopathy and Parkinson's disease, cancer, angiogenesis, autoimmune and inflammatory diseases. We provided an overview of exosome biogenesis and factors that regulate exosome biogenesis. Additionally, we highlight the functions and potential use of MSCs-EXOs in the treatment of the inflammatory disease COVID-19. Finally, we covered a strategies and challenges of MSCs-EXOs. Finally, we discuss conclusion and future perspectives of MSCs-EXOs.

Diagnosis, Classification, and Assessment of the Underlying Etiology of Uveitis by Artificial Intelligence: A Systematic Review

Recent years have seen the emergence and application of artificial intelligence (AI) in diagnostic decision support systems. There are approximately 80 etiologies that can underly uveitis, some very rare, and AI may lend itself to their detection. This synthesis of the literature selected articles that focused on the use of AI in determining the diagnosis, classification, and underlying etiology of uveitis. The AI-based systems demonstrated relatively good performance, with a classification accuracy of 93-99% and a sensitivity of at least 80% for identifying the two most probable etiologies underlying uveitis. However, there were limitations to the evidence. Firstly, most data were collected retrospectively with missing data. Secondly, ophthalmic, demographic, clinical, and ancillary tests were not reliably integrated into the algorithms' dataset. Thirdly, patient numbers were small, which is problematic when aiming to discriminate rare and complex diagnoses. In conclusion, the data indicate that AI has potential as a diagnostic decision support system, but clinical applicability is not yet established. Future studies and technologies need to incorporate more comprehensive clinical data and larger patient populations. In time, these should improve AI-based diagnostic tools and help clinicians diagnose, classify, and manage patients with uveitis.

Single-cell analysis of immune cells on gingiva-derived mesenchymal stem cells in experimental autoimmune uveitis

Gingiva-derived mesenchymal stem cells (GMSCs) have shown astonishing efficacy in the treatment of various autoimmune diseases. However, the mechanisms underlying these immunosuppressive properties remain poorly understood. Here, we generated a lymph node single-cell transcriptomic atlas of GMSC-treated experimental autoimmune uveitis mice. GMSC exerted profound rescue effects on T cells, B cells, dendritic cells, and monocytes. GMSCs rescued the proportion of T helper 17 (Th17) cells and increased the proportion of regulatory T cells. In addition to globally altered transcriptional factors (Fosb and Jund), we observed cell type-dependent gene regulation (e.g., Il17a and Rac1 in Th17 cells), highlighting the GMSCs' cell type-dependent immunomodulatory capacity. GMSCs strongly influenced the phenotypes of Th17 cells, suppressing the formation of the highly inflammatory CCR6-CCR2+ phenotype and enhancing the production of interleukin (IL) -10 in the CCR6+CCR2+ phenotype. Integration of the glucocorticoid-treated transcriptome suggests a more specific immunosuppressive effect of GMSCs on lymphocytes.

Single-cell transcriptomics-based multidisease analysis revealing the molecular dynamics of retinal neurovascular units under inflammatory and hypoxic conditions

The retinal neurovascular unit (NVU) is paramount to maintaining the homeostasis of the retina and determines the progression of various diseases, including diabetic retinopathy (DR), glaucoma, and retinopathy of prematurity (ROP). Although some studies have investigated these diseases, a combined analysis of disease-wide etiology in the NUV at the single-cell level is lacking. Herein, we constructed an atlas of the NVU under inflammatory and hypoxic conditions by integrating single-cell transcriptome data from retinas from wild-type, AireKO, and NdpKO mice. Based on the heterogeneity of the NVU structure and transcriptome diversity under normal and pathological conditions, we discovered two subpopulations of Müller cells: Aqp4^hi and Aqp4^lo cells. Specifically, Aqp4^lo cells expresses phototransduction genes and represent a special type of Müller cell distinct from Aqp4^hi cells, classical Müller cells. AireKO mice exhibit experimental autoimmune uveitis (EAU) with severe damage to the NVU structure, mainly degeneration of Aqp4^hi cells. NdpKO mice exhibited familial exudative vitreoretinopathy (FEVR), with damage to the endothelial barrier, endothelial cell tight junction destruction and basement membrane thickening, accompanied by the reactive secretion of proangiogenic factors by Aqp4^hi cells. In both EAU and FEVR, Aqp4^hi cells are a key factor leading to NVU damage, and the mechanism by which they are generated is regulated by different transcription factors. By studying the pattern of immune cell infiltration in AireKO mice, we constructed a regulatory loop of "inflammatory cells/NVU - monocytes - APCs - Ifng⁺ T cells", providing a new target for blocking the inflammatory cascade. Our elucidation of the cell-specific molecular changes, cell-cell interactions and transcriptional mechanisms of the retinal NVU provides new insights to support the development of multipurpose drugs to block or even reverse NVU damage.

Salivary Exosomes in Health and Disease: Future Prospects in the Eye

Exosomes are a group of vesicles that package and transport DNA, RNA, proteins, and lipids to recipient cells. They can be derived from blood, saliva, urine, and/or other biological tissues. Their impact on several diseases, such as neurodegenerative, autoimmune, and ocular diseases, have been reported, but not fully unraveled. The exosomes that are derived from saliva are less studied, but offer significant advantages over exosomes from other sources, due to their accessibility and ease of collection. Thus, their role in the pathophysiology of diseases is largely unknown. In the context of ocular diseases, salivary exosomes have been under-utilized, thus creating an enormous gap in the literature. The current review discusses the state of exosomes research on systemic and ocular diseases and highlights the role and potential of salivary exosomes as future ocular therapeutic vehicles.

Study of the shared gene signatures of polyarticular juvenile idiopathic arthritis and autoimmune uveitis

Objective

To explore the shared gene signatures and potential molecular mechanisms of polyarticular juvenile idiopathic arthritis (pJIA) and autoimmune uveitis (AU).

Method

The microarray data of pJIA and AU from the Gene Expression Omnibus (GEO) database were downloaded and analyzed. The GEO2R tool was used to identify the shared differentially expressed genes (DEGs) and genes of extracellular proteins were identified among them. Then, weighted gene co-expression network analysis (WGCNA) was used to identify the shared immune-related genes (IRGs) related to pJIA and AU. Moreover, the shared transcription factors (TFs) and microRNAs (miRNAs) in pJIA and AU were acquired by comparing data from HumanTFDB, hTFtarget, GTRD, HMDD, and miRTarBase. Finally, Metascape and g: Profiler were used to carry out function enrichment analyses of previously identified gene sets.

Results

We found 40 up-regulated and 15 down-regulated shared DEGs via GEO2R. Then 24 shared IRGs in positivity-related modules, and 18 shared IRGs in negatively-related modules were found after WGCNA. After that, 3 shared TFs (ARID1A, SMARCC2, SON) were screened. And the constructed TFs-shared DEGs network indicates a central role of ARID1A. Furthermore, hsa-miR-146 was found important in both diseases. The gene sets enrichment analyses suggested up-regulated shared DEGs, TFs targeted shared DEGs, and IRGs positivity-correlated with both diseases mainly enriched in neutrophil degranulation process, IL-4, IL-13, and cytokine signaling pathways. The IRGs negatively correlated with pJIA and AU mainly influence functions of the natural killer cell, cytotoxicity, and glomerular mesangial cell proliferation. The down-regulated shared DEGs and TFs targeted shared DEGs did not show particular functional enrichment.

Conclusion

Our study fully demonstrated the flexibility and complexity of the immune system disorders involved in pJIA and AU. Neutrophil degranulation may be considered the shared pathogenic mechanism, and the roles of ARID1A and MiR-146a are worthy of further in-depth study. Other than that, the importance of periodic inspection of kidney function is also noteworthy.

JAK-STAT Signaling Pathway in Non-Infectious Uveitis

Non-infectious uveitis (NIU) refers to various intraocular inflammatory disorders responsible for severe visual loss. Cytokines participate in the regulation of ocular homeostasis and NIU pathological processes. Cytokine receptors transmit signals by activating Janus kinase (JAK) and signal transducer and activator of transcription (STAT) proteins. Increasing evidence from human NIU and experimental models reveals the involvement of the JAK-STAT signaling pathway in NIU pathogenesis. Several small-molecule drugs that potentially inhibit multiple cytokine-dependent pathways are under investigation for treating autoimmune diseases, implicating possible applications for NIU treatment. This review summarizes the current understanding of the diverse roles of the JAK-STAT signaling pathway in ocular homeostasis and NIU pathology, providing a rationale for targeting JAKs and STATs for NIU treatment. Moreover, available evidence for the safety and efficacy of JAK inhibitors for refractory uveitis and potential approaches for treatment optimization are discussed.

[Clinical aspects, diagnostics and differential diagnostics of uveitis for rheumatologists]

This review article presents the different forms of uveitis and their clinical manifestations. The exact type and localization of the ocular inflammation is crucial for the probability of the underlying rheumatological disease and thus for a correct differential diagnosis. In this first part, in addition to the anatomy of the eye, the different forms of uveitis including the associated nomenclature, typical symptoms, diagnostics and possible complications are presented. In a following second part ("Association of the different forms of uveitis with inflammatory rheumatic diseases and their treatment"), the associations with rheumatological and other systemic diseases are explained and highlighted from an ophthalmological and rheumatological perspective.

Single subcutaneous injection of the minocycline nanocomposite-loaded thermosensitive hydrogel for the effective attenuation of experimental autoimmune uveitis

Autoimmune uveitis induces a serious pathological and inflammatory response in the retina/choroid and results in vision impairment and blindness. Here, we report a minocycline (Mino) nanocomposite-loaded hydrogel offering a high drug payload and sustained drug release for the effective control of ocular inflammation via a single subcutaneous injection. In the presence of divalent cations (i.e., Ca²⁺), Mino was found to co-assemble with a phosphorylated peptide (i.e., NapGFFpY) via electrostatic interaction and consequently generating Mino nanocomposite. The drug entrapment efficiency (EE) of the Mino nanocomposite varied from 29.93±0.76% to 67.90±6.57%, depending on different component concentrations. After incorporation into 30 wt% poly (D,L-lactide)-b-poly (ethylene glycol)-b-poly (D,L-lactide) (PDLLA-PEG-PDLLA) thermosensitive hydrogel, the resulting Mino nanocomposite-loaded hydrogel provided a sustained drug release over 21 days. In the experimental autoimmune uveitis (EAU) rat model, a single subcutaneous injection of the Mino nanocomposite-loaded hydrogel effectively alleviated ocular inflammation in a dose-dependent manner. As indicated by optical coherence tomography (OCT) and electroretinogram (ERG) measurements, the Mino nanocomposite-loaded hydrogel treatment not only remarkably reduced destruction of the retina by EAU, but also greatly rescued retinal functions. Moreover, the proposed Mino nanocomposite-loaded hydrogel exerted its therapeutic effect on EAU primarily through a significant reduction of the influx of leukocytes and Th17 cells as well as suppression of microglia activation and apoptosis in the retina. Overall, the proposed Mino nanocomposite-loaded hydrogel might be a promising strategy for the clinical management of EAU.

Depletion of Retinal Dopaminergic Activity in a Mouse Model of Rod Dysfunction Exacerbates Experimental Autoimmune Uveoretinitis: A Role for the Gateway Reflex

The gateway reflex is a mechanism by which neural inputs regulate chemokine expression at endothelial cell barriers, thereby establishing gateways for the invasion of autoreactive T cells into barrier-protected tissues. In this study, we hypothesized that rod photoreceptor dysfunction causes remodeling of retinal neural activity, which influences the blood–retinal barrier and the development of retinal inflammation. We evaluated this hypothesis using Gnat1^rd17 mice, a model of night blindness with late-onset rod-cone dystrophy, and experimental autoimmune uveoretinitis (EAU). Retinal remodeling and its effect on EAU development were investigated by transcriptome profiling, target identification, and functional validation. We showed that Gnat1^rd17 mice primarily underwent alterations in their retinal dopaminergic system, triggering the development of an exacerbated EAU, which was counteracted by dopamine replacement with L-DOPA administered either systemically or locally. Remarkably, dopamine acted on retinal endothelial cells to inhibit NF-κB and STAT3 activity and the expression of downstream target genes such as chemokines involved in T cell recruitment. These results suggest that rod-mediated dopamine release functions in a gateway reflex manner in the homeostatic control of immune cell entry into the retina, and the loss of retinal dopaminergic activity in conditions associated with rod dysfunction increases the susceptibility to autoimmune uveitis.

Bilateral Recurrent Uveitis in a Young Patient with Family History of Spondyloarthritis: Spondyloarthritis or Not?

We present the case of a young man with a strong family history of SpA, who was referred to the Rheumatology Clinic due to bilateral uveitis refractory to treatment with corticosteroids. The patient’s renal function gradually deteriorated and a subsequent biopsy was positive for interstitial nephritis. After excluding all other systemic diseases, the diagnosis of TINU syndrome was confirmed. Although rare, TINU syndrome should be considered in the differential diagnosis of non-infective uveitis especially in the presence of urinalysis abnormalities.

Therapeutic Implications of Mesenchymal Stromal Cells and Their Extracellular Vesicles in Autoimmune Diseases: From Biology to Clinical Applications

Mesenchymal stromal cells (MSCs) are perivascular multipotent stem cells originally identified in the bone marrow (BM) stroma and subsequently in virtually all vascularized tissues. Because of their ability to differentiate into various mesodermal lineages, their trophic properties, homing capacity, and immunomodulatory functions, MSCs have emerged as attractive candidates in tissue repair and treatment of autoimmune disorders. Accumulating evidence suggests that the beneficial effects of MSCs may be primarily mediated via a number of paracrine-acting soluble factors and extracellular vesicles (EVs). EVs are membrane-coated vesicles that are increasingly being acknowledged as playing a key role in intercellular communication via their capacity to carry and deliver their cargo, consisting of proteins, nucleic acids, and lipids to recipient cells. MSC-EVs recapitulate the functions of the cells they originate, including immunoregulatory effects but do not seem to be associated with the limitations and concerns of cell-based therapies, thereby emerging as an appealing alternative therapeutic option in immune-mediated disorders. In the present review, the biology of MSCs will be outlined and an overview of their immunomodulatory functions will be provided. In addition, current knowledge on the features of MSC-EVs and their immunoregulatory potential will be summarized. Finally, therapeutic applications of MSCs and MSC-EVs in autoimmune disorders will be discussed.

Development and Validation of a Bayesian Network for Supporting the Etiological Diagnosis of Uveitis

The etiological diagnosis of uveitis is complex. We aimed to implement and validate a Bayesian belief network algorithm for the differential diagnosis of the most relevant causes of uveitis. The training dataset (n = 897) and the test dataset (n = 154) were composed of all incident cases of uveitis admitted to two internal medicine departments, in two independent French centers (Lyon, 2003-2016 and Dijon, 2015-2017). The etiologies of uveitis were classified into eight groups. The algorithm was based on simple epidemiological characteristics (age, gender, and ethnicity) and anatomoclinical features of uveitis. The cross-validated estimate obtained in the training dataset concluded that the etiology of uveitis determined by the experts corresponded to one of the two most probable diagnoses in at least 77% of the cases. In the test dataset, this probability reached at least 83%. For the training and test datasets, when the most likely diagnosis was considered, the highest sensitivity was obtained for spondyloarthritis and HLA-B27-related uveitis (76% and 63%, respectively). The respective specificities were 93% and 54%. This algorithm could help junior and general ophthalmologists in the differential diagnosis of uveitis. It could guide the diagnostic work-up and help in the selection of further diagnostic investigations.

Altered Metabolic Phenotype of Immune Cells in a Spontaneous Autoimmune Uveitis Model

As one of the leading causes of blindness worldwide, uveitis is an important disease. The exact pathogenesis of autoimmune uveitis is not entirely elucidated to date. Equine recurrent uveitis (ERU) represents the only spontaneous animal model for autoimmune uveitis in humans. As the metabolism of immune cells is an emerging field in research and gains more and more significance to take part in the pathogenesis of various diseases, we conducted experiments to investigate the metabolism of immune cells of ERU cases and healthy controls. To our knowledge, the link between a deviant immunometabolism and the pathogenesis of autoimmune uveitis was not investigated so far. We showed that PBMC of ERU cases had a more active metabolic phenotype in basal state by upregulating both the oxidative phosphorylation and the glycolytic pathway. We further revealed an increased compensatory glycolytic rate of PBMC and CD4⁺ T cells of ERU cases under mitochondrial stress conditions. These findings are in line with metabolic alterations of immune cells in other autoimmune diseases and basic research, where it was shown that activated immune cells have an increased need of energy and molecule demand for their effector function. We demonstrated a clear difference in the metabolic phenotypes of PBMC and, more specifically, CD4⁺ T cells of ERU cases and controls. These findings are another important step in understanding the pathogenesis of ERU and figuratively, human autoimmune uveitis.

Perspectives for immunotherapy in noninfectious immune mediated uveitis

Introduction: Noninfectious uveitis (NIU) is one of the leading causes of blindness worldwide. In adult patients, anterior NIU is usually managed with topical corticosteroids. In intermediate, posterior uveitis. and panuveitis, systemic corticosteroids are used especially in case of bilaterality or association with systemic disease. Biotherapies are recommended in case of inefficacy or intolerance to corticosteroids or conventional immunosuppressive drugs. Anti-TNF-α agents are by far the most widely used biotherapies. In case of failure or poor tolerance to anti-TNF-α, new targeted therapies can be proposed.Areas covered: We present and discuss an updated overview on biologics and biotherapies in NIU.Expert opinion: In case of dependency to systemic or intravitreal steroids, sight-threatening disease, and/or failure of conventional immunosuppressive drugs, anti-TNF-α are used as first-line biologics to achieve quiescence of inflammation. Anti-interleukin-6 is another option that may be proposed as first-line biologic or in case of poor efficacy of anti-TNF-α. Interferon can be directly proposed in specific indications (e.g. refractory macular edema, sight-threatening Behçet's uveitis). In the rare cases that remain unresponsive to traditional biotherapies, novel molecules, such as Janus-associated-kinase and anti-phosphodiesterase-4-inhibitors can be used. Therapeutic response must always be evaluated by clinical and appropriate ancillary investigations.

A Review of the Various Roles and Participation Levels of B-Cells in Non-Infectious Uveitis

Non-infectious uveitis is an inflammatory disorder of the eye that accounts for severe visual loss without evident infectious agents. While T cells are supposed to dominate the induction of inflammation in non-infectious uveitis, the role of B cells in the pathogenesis of this disease is obscure. Therefore, this review aimed to discuss diverse B-cell participation in different non-infectious uveitides and their roles in the pathogenesis of this disease as well as the mechanism of action of rituximab. Increasing evidence from experimental models and human non-infectious uveitis has suggested the participation of B cells in non-infectious uveitis. The participation levels vary in different uveitides. Furthermore, B cells play multiple roles in the pathogenic mechanisms. B cells produce autoantibodies, regulate T cell responses via antibody-independent functions, and constitute ectopic lymphoid structures. Regulatory B cells perform pivotal anti-inflammatory functions in non-infectious uveitis. Rituximab may work by depleting pro-inflammatory B cells and restoring the quantity and function of regulatory B cells in this disease. Identifying the levels of B-cell participation and the associated roles is beneficial for optimizing therapy. Diversified experimental model choices and emerging tools and/or methods are conducive for future studies on this topic.

Licarin A as a Novel Drug for Inflammatory Eye Diseases

Purpose: This study investigated the safety and therapeutic efficacy of licarin A (LCA) in the treatment of intraocular inflammation. Methods: In vitro safety of LCA in retinal pigmented epithelial cells (ARPE-19) and human embryonic stem cell derived-retinal pigmented epithelial cells (hES-RPE) was evaluated using CellTiter-Blue^® kit. The chorioallantoic membrane (CAM) assay was used to investigate LCA safety and antiangiogenic activity. In vivo safety of intravitreal LCA was accomplished by clinical examination (including assessment of intraocular pressure), electroretinography (ERG), and histopathology. Uveitis was induced in rats by subcutaneous and intravitreal injection of bacillus Calmette-Guérin (BCG) antigen of Mycobacterium bovis. Intraocular inflammation was graded by slit-lamp and fundus examination, ERG, and histopathology. Results: LCA was safe to cells and to the CAM at concentration below 12.0 μM. LCA significantly reduced the percentage of blood vessels in the CAM. Retinal safety and anti-inflammatory efficacy of intravitreal injection of LCA 6.0 μM were confirmed through clinical, functional, and histopathological evaluation. Significant reduction of inflammatory cytokines (tumor necrosis factor-α and interleukin-6) was also found, when compared to untreated animals. Conclusion: The results suggest that LCA is a potential new drug for the treatment of inflammatory eye disease.

Uveitis as an Open Window to Systemic Inflammatory Diseases

Spondyloarthritis (Spa), Behçet's disease (BD) and sarcoidosis are major systemic inflammatory diseases worldwide. They are all multisystem pathologies and share a possible ocular involvement, especially uveitis. We hereby describe selected cases who were referred by ophthalmologists to our internal medicine department for unexplained uveitis. Physical examination and/or the use of laboratory and imaging investigations allowed to make a diagnosis of a systemic inflammatory disease in a large proportion of patients. In our tertiary referral center, 75 patients have been diagnosed with Spa (n = 20), BD (n = 9), or sarcoidosis (n = 46) in the last two years. There was a significant delay in the diagnosis of Spa-associated uveitis. Screening strategies using Human Leukocyte Antigen (HLA)-B27 determination and sacroiliac magnetic resonance imaging in patients suffering from chronic low back pain and/or psoriasis helped in the diagnosis. BD's uveitis affects young people from both sexes and all origins and usually presents with panuveitis and retinal vasculitis. The high proportion of sarcoidosis in our population is explained by the use of chest computed tomography (CT) and 18F-fluorodeoxyglucose positron emission tomography CT that helped to identify smaller hilar or mediastinal involvement and allowed to further investigate those patients, especially in the elderly. Our results confirm how in these sight- and potentially life-threatening diseases a prompt diagnosis is mandatory and benefits from a multidisciplinary approach.

Sirolimus-Loaded Intravitreal Implant for Effective Treatment of Experimental Uveitis

Non-infectious uveitis, an ocular inflammatory condition that affects the iris, ciliary body, choroid, and adjacent tissues (retina, optic nerve, and vitreous), is an important cause of blindness worldwide. Sirolimus (SRL), a potent immunomodulatory drug, has shown promising results in the treatment of inflammatory ocular diseases. Despite this therapeutic potential, its clinical use is a major challenge due to low bioavailability and poor solubility. Poly(lactic-co-glycolic acid) (PLGA) is a biodegradable polymer commonly used for ophthalmic drug delivery due to its suitable characteristics such as biocompatibility, good mechanical properties, and improvement of the pharmacokinetic profile of the drug. In the present study, we investigated the effects of SRL-PLGA implant on experimental autoimmune uveitis in rabbits. Clinical and histopathological examinations were performed, followed by assessment of protein levels and determination of myeloperoxidase (MPO) and N-acetylglucosaminidase (NAG) activity in the aqueous humor/vitreous. As a result, treated eyes had decreased average inflammatory scores, protein significant decreases in treated eyes, assessed after 35 days. Histopathological examination showed less severe intraocular inflammation and decreased tissue damage in treated eyes. According to these results, the SRL-PLGA implant evaluated in this study was apparently safe, reducing inflammation in treated eyes, with an extended effect possibly associated with prolonged release of SRL in the posterior segment of the eye. Therefore, intravitreal SRL-PLGA implant could be a promising alternative for treatment of non-infectious uveitis.

Vogt-Koyanagi-Harada disease: a retrospective and multicentric study of 41 patients

Background

East and South East Asian subjects as well as Amerindians and Hispanic subjects are predominantly affected by Vogt-Koyanagi-Harada disease.

In Europe, only few studies have described the clinical features and treatment of this disease, especially in France.

Methods

This retrospective case series was based on data collected from patients with a VKH disease diagnosed from January 2000 to March 2017, provided by three French Tertiary Centers.

Results

Forty-one patients (16 men and 25 women) were diagnosed: average age at diagnosis was 38.7 years. Patients were mainly from Maghreb (58%), but ethnic origins were multiple. Pleiocytosis was observed in 19 cases (63%) and 17 out of 41 patients showed audio vestibular signs (41%), and 11 showed skin signs (27%). Thirty-four were treated with corticosteroids (83%), 11 with an immunosuppressant treatment (27%) and 5 with biological therapy drugs (13%). Relapse was observed in 41% patients, even though final average visual acuity had improved. We did not find any significant clinical difference in the population from Maghreb compared to other populations, but for age and sex trends, since there was a majority of younger women.

Conclusion

We report here the second largest French cohort reported to date to our knowledge. The multiethnicity in our study suggests that VKH disease should be evoked whatever patients’ ethnicity.

Comparison of topically administered 0.05% difluprednate and 1% prednisolone acetate for inhibition of aqueocentesis-induced breakdown of the blood-aqueous barrier in healthy dogs

OBJECTIVE

To compare the efficacy of 0.05% difluprednate ophthalmic emulsion and 1% prednisolone acetate ophthalmic suspension for controlling aqueocentesis-induced breakdown of the blood-aqueous barrier in healthy dogs.

ANIMALS

34 healthy dogs.

PROCEDURES

Dogs were allocated to 5 groups (6 to 8 dogs/group) to receive 0.05% difluprednate, 1% prednisolone acetate, or saline (0.9% NaCl) solution (control treatment) in both eyes 2 or 4 times daily. Eye drops were administered topically for 5 consecutive days. Anterior chamber paracentesis (aqueocentesis) was performed in 1 eye on the third day. Automated fluorophotometry was performed immediately before and 20 minutes and 24 and 48 hours after aqueocentesis. Relative fluorescence (RF), defined as fluorescence of the eye that had undergone aqueocentesis divided by fluorescence of the contralateral eye, was calculated to help control for variation among dogs.

RESULTS

Mean RF was significantly lower at 24 hours after aqueocentesis in dogs treated twice daily with 0.05% difluprednate or 4 times daily with 1% prednisolone acetate than in dogs receiving the control treatment. At 48 hours after aqueocentesis, mean RF was significantly lower in dogs treated 4 times daily with 1% prednisolone acetate than in control dogs. Mean RF differed over time in dogs treated 4 times daily with 0.05% difluprednate but did not differ over time for any of the other treatments.

CONCLUSIONS AND CLINICAL RELEVANCE

All 4 treatments were effective for reducing aqueocentesis-induced anterior uveitis in healthy dogs regardless of the drug or frequency of administration. Topical ophthalmic administration of 0.05% difluprednate may be a viable treatment option for dogs with anterior uveitis and warrants further study.

The use of biologic agents in the management of uveitis

The uveitides are a heterogenous group of ocular inflammatory disorders that account for the third highest cause of blindness worldwide, responsible for 5-10% of visual impairment globally. Up to 35% of patients with uveitis can suffer significant vision loss. To prevent irreversible structural damage and blindness, it is important that the diagnosis and commencement of appropriate therapy occurs promptly. Management includes topical and systemic corticosteroid therapy and conventional immunomodulatory agents, including methotrexate, azathioprine, mycophenolate mofetil and cyclosporin. Significant progress has been made in the past decade in our understanding of the immunopathological pathways that drive intraocular inflammation, allowing the development of targeted therapy with biologic agents. These include TNF-α inhibitors, such as infliximab, adalimumab and etanercept; interleukin blockers, such as tocilizumab and daclizumab; and other targeted therapies, such as rituximab and abatacept. The efficacy of these agents has been studied in cases of severe uveitis that are refractory to conventional immunomodulatory agents and provide exciting results that have revolutionised uveitis management. Though the biologic era has provided a large armamentarium to treat uveitis, ongoing challenges and cases of recalcitrant uveitis remain, posing a challenge to internal medicine physicians. This comprehensive review aims to construct an updated summary on the existing evidence pertaining to the use of biologic agents in the treatment of uveitis. Methods include a systematic search for studies between 2000 and 2018 using PubMed, EMBASE, Ovid MEDLINE and Cochrane libraries.

Intravitreal thalidomide ameliorates inflammation in a model of experimental uveitis induced by BCG

Uveitis encompasses a heterogeneous and complex group of conditions characterized by intraocular inflammation, frequently affecting young individuals and representing an important cause of irreversible blindness worldwide. Animal models have been critical to understand etiology and pathogenesis of uveitis, being also employed to assess new therapeutic strategies, preceding human studies. However, there is still a need of developing and studying different models, due to the difficulties in recapitulating all forms of human uveitis effectively. Although corticosteroids are usually the first-line therapy for non-infectious uveitis, their long-term use is limited by potentially serious side effects in all possible delivery routes. Thus, thalidomide, a drug with anti-inflammatory and antiangiogenic properties, was investigated in a novel experimental model of uveitis, induced by Mycobacterium bovis Calmette-Guérin Bacillus (BCG), in rabbits. The experimental protocol consisted of two subcutaneous injections of BCG, followed by two intravitreal injections of the same antigen, inducing panuveitis. Animals were treated with a single intravitreal injection of thalidomide suspension or PBS. Clinical manifestations of uveitis improved after intravitreal thalidomide, involving both anterior and posterior segments. Protein content, N-acetyl-b-glucosaminidase (NAG) and myeloperoxidase (MPO) activities were elevated in ocular tissues after disease induction, further decreasing post-treatment with intravitreal thalidomide. This therapeutic response was also confirmed on ocular electrophysiology, as well as histopathology. This experimental model induced panuveitis in rabbits using a low-cost mycobacterial antigen, with intraocular inflammation subsequently improving after treatment. Intravitreal thalidomide may be a potential alternative to treat intraocular inflammation in corticosteroid-sparing therapies.

Cytokine Profiling in Aqueous Humor Samples From Patients With Non-Infectious Uveitis Associated With Systemic Inflammatory Diseases

Non-infectious uveitis are intraocular inflammatory conditions caused by dysregulated activation of the immune response without any detectable infectious agents. The aim of this study was to explore potential markers and therapeutic targets for two distinct types of non-infectious uveitis associated with Behçet's disease (BD) and Vogt Koyanagi Harada (VKH) disease. Concentrations of 27 cytokines were investigated in aqueous humor (AH) samples from patients with active uveitis vs. healthy controls (HC) (n = 10 patients with BD-associated uveitis; n = 10 patients with VKH-associated uveitis; n = 10 HC) using the Bio-Plex Pro^TM human cytokine group I panel. Additionally, leukocytes in AH samples were counted with hemocytometers and characterized by flow cytometry. Eleven cytokines were differentially expressed between patients with uveitis and HC with a median concentration greater than 10 pg/ml. IL-6, IP-10, G-CSF, and IFNγ showed higher concentrations in AH samples from both BD and VKH patients while IL-2, IL-8, IL-13, TNFα, eotaxin, IL-1ra showed statistically significant higher concentrations only in AH samples from BD patients. GM-CSF was the sole cytokine with an opposite profile showing decreased levels in AH samples from BD patients. IL-1ra and IL-6 were detected at higher frequencies in AH samples from BD and VKH patients compared with those from HC while IFNγ and TNFα were not detected in HC. The concentrations of IL-6, IL-8, IP-10, G-CSF, IFNγ, TNFα, eotaxin, IL-1ra positively correlated with the concentrations of leukocytes in AH, suggesting that such cytokines can be produced by immune cells and/or attract and/or promote proliferation and survival of immune cells in these types of uveitis. The correlation matrix of cytokine concentrations in AH samples revealed that IFNγ, TNFα, eotaxin, IL-6, G-CSF highly correlated each other. The ratios of cytokine concentrations between AH and plasma intra-individuals showed that IL-2, IL-6, IP-10, GM-CSF were increased intraocularly. In conclusion, AH sampling followed by multiplex analysis of cytokines should be fostered in non-infectious uveitis to identify cytokines dysregulated intraocularly in each individual laying the groundwork for precision medicine.

Can the CRP/albumin Ratio be Used as a New Indicator of Activation in Patients with Uveitis?

Purpose: To evaluate whether the C-reactive protein (CRP)/albumin ratio (CAR) in patients with uveitis during an attack is a marker that can give information about the activity, severity and prognosis of the disease.Methods: This study included 35 patients with an uveitis attack and 35 healthy volunteers. The localization and severity of uveitis were recorded. Patients' complete blood count (CBC) during the attack, CRP, CAR, erythrocyte sedimentation rate(ESR), neutrophil/lymphocyte ratio(NLR), and platelet/lymphocyte ratio(PLR) were recorded.Results: The mean age was 34.1 ± 12.5 years for the 35 uveitis cases and 30.1 ± 4.1 years for the healthy volunteers. CRP and CAR were significantly higher in uveitis patients (p = .015 and 0.011, respectively). While CRP and CAR were significantly higher in severe anterior uveitis than mild anterior uveitis (p = .036 and 0.022, respectively), only CAR was significantly higher in severe posterior and panuveitis than mild ones(p = .017).Conclusion: CAR may be an important parameter in determining the activation of the uveitis.

[Uveitis: Diagnosis and work-up]

Uveitis is an inflammation of the uveal tissue: iris, ciliary body and choroid. The annual incidence of uveitis in France is low (17/100,000), but visual and therapeutic consequences may be severe. Etiologic investigation is thus a fundamental step in the management of any uveitis. The history plays an important role in the initial evaluation; it must be methodic. The ophthalmologic examination seeks to classify the uveitis by type (granulomatous or not), location (anterior, intermediate or posterior), severity, duration and recurrence. Systemic signs often orient the diagnosis toward a specific cause. The diagnostic approach to uveitis relies on the history, ophthalmologic examination and evaluation of possible extraocular manifestations. Ancillary testing must be prescribed based on the clinical differential diagnosis, without which their yield is very low.

Lymphocyte Immunophenotyping and CD4/CD8 Ratio in Cerebrospinal Fluid for the Diagnosis of Sarcoidosis-related Uveitis

Background: This study aimed to assess the diagnostic relevance of CD4/CD8 ratio in cerebrospinal fluid (CSF) for the etiological diagnosis work-up of uveitis.Methods: We consecutively included patients who were referred to our department for the diagnostic workup of intermediate and/or posterior uveitis. Etiological diagnoses were established in a blind manner regarding CD4/CD8 ratio.Results: Fifty-two patients were included. A diagnosis of ocular sarcoidosis was made in 15 (29%) patients, 21% had another determined diagnosis while 50% remained of undetermined origin. Median CD4/CD8 ratio in CSF was 4.57 (IQR 3.39-5.47) in ocular sarcoidosis, 1.74 (1.60-3.18) in uveitis due to other determined cause (P = .008), and 2.83 (2.34-3.54) in those with uveitis of undetermined origin (P = .007). CD4/CD8 ratio >3.23 was associated with a diagnosis of ocular sarcoidosis.Conclusion: Determination of CD4/CD8 ratio in CSF can be useful for diagnosis work-up since a CD4/CD8 ratio >3.23 in CSF is associated with ocular sarcoidosis.

Uveitis: Autoimmunity… and beyond

OBJECTIVE

Uveitis is the most common ophthalmological finding in the practice of rheumatology and clinical immunology. The condition is frequently idiopathic but about 60 causes of uveitis have been described. Our aim was to analyze the clinical patterns and etiologies of uveitis in a tertiary referral center.

METHODS

The records of 912 consecutive patients referred to the department of internal medicine (Lyon University Hospital, Lyon, France) for the diagnostic work-up of uveitis were examined. Demographic, clinical, anatomical, and etiological features of uveitis were analyzed.

RESULTS

The mean age at onset was 48.8 years; 59.8% of the patients were women and 78.2% were Caucasians. Anterior uveitis was the most common type of uveitis (40.6%), followed by panuveitis (31.7%), posterior (18.75%) and intermediate uveitis (9%). 46.9% of the patients had idiopathic uveitis. The most common etiologies were systemic diseases (37.3%), such as sarcoidosis (17.1%), HLA-B27-related uveitis and/or spondyloarthritis (12.5%), and tuberculosis (7.5%).

CONCLUSION

We describe one of the largest cohorts of consecutive uveitis patients referred to a department of internal medicine. The high percentage of uveitis associated with underlying (systemic) diseases highlights the need for a multidisciplinary approach, in order to reduce the diagnostic delay.

Do systemic steroids increase the risk of ocular complication in uveitis patients? Focus on a Italian referral center

INTRODUCTION

To describe the ocular inflammatory and iatrogenic complications in a cohort of uveitic patients treated in an Italian referral centre.

MATERIAL AND METHODS

Retrospective non-comparative case series. Medical history and clinical findings of all consecutive patients referred to the uveitis center of Pisa University from January 2015 to January 2017 were reviewed. Only patients with at least three follow-up visits in our center were included in our series.

RESULTS

Three hundred and eighty-nine patients were visited in our center during study period; only 142 patients (90 men and 52 female) satisfied the inclusion criteria. Mean age at presentation was 41 ± 14 years. The most common ocular feature was anterior uveitis (46%) and was mainly unilateral. A specific etiological diagnosis was established in 61% of patients. At presentation, 71.43% of patients were on medical therapy for rheumatic disease; 42.86% of patients used systemic steroids Cataract and ocular hypertension were the most common ocular complications during the study period but were not statistically related to systemic steroid treatment.

CONCLUSIONS

Systemic steroids treatment in uveitis patients does not seem to increase the risk of iatrogenic complications such as cataract and glaucoma. In our series, increasing age appears to be the main risk factor for cataract and glaucoma development. Key points • Cataract, ocular hypertension, and glaucoma are the most common iatrogenic complications. • Systemic steroids can be safely used in uveitis patients.

Expert opinion on the use of biological therapy in non-infectious uveitis

INTRODUCTION

Conventional immunosuppressive drugs, anti-TNF alpha treatments and biotherapies are increasingly being used in non-infectious uveitis.

AREAS COVERED

The present work was led by a multidisciplinary panel of experts, including internal medicine specialists, rheumatologists and ophthalmologists, and proposes an extensive review on the use of biological agents in non-infectious uveitis.

EXPERT OPINION

In case of dependency to steroids or sight-threatening disease, conventional immunosuppressive drugs (methotrexate, azathioprine and mycophenolate mofetil) and/or biological therapies such as anti-TNF alpha treatments (adalimumab, infliximab) can be used to achieve and maintain disease quiescence. Interferon is an efficient immunomodulatory drug that can be proposed as second-line therapy in specific indications (eg. refractory macular edema, sight-threatening Behçet's uveitis). Other biologics, especially tocilizumab, are showing promising results. Local treatments (steroids, sirolimus etc.) can be used as adjuvant therapies in case of unilateral relapse. Therapeutic response must always be evaluated by clinical examination and appropriate ancillary investigations.

Exploring the role of programmed cell death protein 1 and its ligand 1 in eye diseases

Programmed death receptor-1 (PD-1) and its ligand, PD-L1, as negative co-stimulatory molecules, are indispensable for regulating both physiological and pathological immune responses. The PD-1/PD-L1-mediated signaling pathway has been studied extensively in cancer research and has become a hotspot for biopharmaceuticals and immunotherapy. Furthermore, monoclonal antibodies to PD-1 have just been approved by the US Food and Drug Administration to treat certain types of malignancies. Recent research has unveiled a close association between the PD-1/PD-L1 system and eye diseases. This review describes the expression and physiological functions of PD-1 and its ligand in ocular tissues and summarizes the pathogenic, regulatory, and therapeutic roles of PD-1/PD-L1 system in eye diseases, including uveal melanoma, autoimmune uveitis, autoimmune dry eye, sympathetic ophthalmia, Graves' ophthalmopathy, diabetic retinopathy, herpes simplex keratitis, and trachoma, with the intent of highlighting the potential of PD-1/PD-L1 as novel therapeutic targets or biomarkers for these ocular diseases.

The Management of Acute Anterior Uveitis Complicating Spondyloarthritis: Present and Future

Spondyloarthropathies (SpA) encompass a group of chronic inflammatory diseases sharing common genetic and clinical features, including the association with HLA-B27 antigen, the involvement of both the axial and the peripheral skeleton, the presence of dactylitis, enthesitis, and typical extra-articular manifestations such as psoriasis, inflammatory bowel disease, and acute anterior uveitis (AAU). The latter is commonly reported as a noninfectious acute inflammation of the anterior uveal tract and its adjacent structures. AAU may affect more than 20% of SpA patients representing the most common extra-articular manifestation of the disease. Considering the potential consequences of untreated AAU, early diagnosis and aggressive treatment are crucial to avoid complications of remittent or chronic eye inflammation, such as visual loss and blindness. The management of SpA has dramatically improved over the last decades due to the development of new treat-to-target strategies and to the introduction of biologic disease modifying antirheumatic drugs (bDMARDs), particularly tumor necrosis factor alpha inhibitors (TNFis), currently used for the treatment of nonresponder patients to conventional synthetic agents. Along with the improvement of musculoskeletal features of SpA, bDMARDs provided an additional effect also in the management of AAU in those patients who are failures to topical and systemic conventional therapies. Nowadays, five TNFis, one interleukin-17, and one interleukin 12/23 blocker are licensed for the treatment of SpA, with different proven efficacy in preventing and treating ocular involvement. The aim of this review is to summarize the current options and to analyze the future perspectives for the management of SpA-associated AAU.

Uveitis of Unknown Etiology: Clinical and Outcome features. A Retrospective Analysis of 355 Patients

Purpose: Despite the huge advance in diagnostic technics, about one-third of uveitis is still considered of unknown etiology. In this study, we aimed to report their clinical features and to describe how a diagnosis has been finally reached for some patients.Methods: We retrospectively reviewed all patients with uveitis referred to our tertiary center between 2002 and 2016. The unknown etiology was admitted after a new ophthalmologic examination and a full work-up in internal medicine in our tertiary center.Results: Among 957 patients with uveitis, 355 had uveitis of unknown etiology. The clinical and epidemiological characteristics of this subgroup were no different from those with a known etiology. Out of 104 patients who were followed-up for more than 1 year, a diagnosis was finally achieved in 20 patients. The diagnosis was determined either because of the occurrence of a new clinical symptom (n = 10), a new/repeated non-ophthalmologic investigation (n = 7), or a new/repeated ophthalmic exam (n = 3).Conclusion: A prolonged follow-up, with repeated exams, may allow the determination of an etiology in about one-fifth of uveitis initially considered as idiopathic.

Subretinal Transplantation of Human Amniotic Epithelial Cells in the Treatment of Autoimmune Uveitis in Rats

As a featured ocular inflammatory disease, autoimmune uveitis is the major cause of blindness in the clinic. Although current immunosuppressive regimens can alleviate the progression of autoimmune uveitis, they have serious side effects. Therefore, an alternative therapeutic strategy is urgently required. The present study investigated the therapeutic efficacy of human amniotic epithelial cells (hAECs) on autoimmune uveitis in a rat model. Herein, experimental autoimmune uveitis (EAU) was induced in rats via a subcutaneous injection of interphotoreceptor retinoid-binding protein. EAU rats were treated with hAECs or the vehicle solution via a subretinal injection on day 0 and day 6 after immunization, and rats were sacrificed on day 12 and day 18 for further analysis. The pathological development of EAU was evaluated by slit lamp microscopy. Immune cell infiltration and retinal structure damage were examined by histological examination of hematoxylin and eosin (H&E) and immunofluorescence staining. T-cell subsets were detected by flow cytometry, and the levels of inflammatory cytokines were quantified by enzyme-linked immunosorbent assay (ELISA). hAEC treatment ameliorated the pathological progression of EAU and preserved the retinal structure organization and thickness, especially in the preventive group that received a subretinal injection on day 0. Moreover, hAECs inhibited the retinal infiltration of macrophages and T-cells. Mechanistically, hAECs modulated the balance of T-cell subsets by downregulating T helper (Th)17 cells and upregulating T regulatory (Treg) cells, as confirmed by decreased interleukin (IL)-17 and increased IL-10 levels in the spleens and lymph nodes of EAU rats. Furthermore, hAECs improved the local cytokine environment in EAU rats by suppressing the monocyte chemoattractant protein (MCP)-1, IL-17 and interferon (IFN)-γ levels and enhancing the IL-10 in the aqueous humor. Therefore, subretinal transplantation of hAECs in EAU rats ameliorated ocular inflammation, preserved the retinal structure and coordinated the immune balance. The current study provides a novel therapeutic strategy for autoimmune uveitis and related ocular inflammatory diseases in the clinic.

Effects of Post-Treatment Hydrogen Gas Inhalation on Uveitis Induced by Endotoxin in Rats

Background

Molecular hydrogen (H₂) has been widely reported to have benefiicial effects in diverse animal models and human disease through reduction of oxidative stress and inflammation. The aim of this study was to investigate whether hydrogen gas could ameliorate endotoxin-induced uveitis (EIU) in rats.

Material/Methods

Male Sprague-Dawley rats were divided into a normal group, a model group, a nitrogen-oxygen (N-O) group, and a hydrogen-oxygen (H-O) group. EIU was induced in rats of the latter 3 groups by injection of lipopolysaccharide (LPS). After that, rats in the N-O group inhaled a gas mixture of 67% N₂ and 33% O₂, while those in the H-O group inhaled a gas mixture of 67% H₂ and 33% O₂. All rats were graded according to the signs of uveitis after electroretinography (ERG) examination. Protein concentration in the aqueous humor (AqH) was measured. Furthermore, hematoxylin-eosin staining and immunostaining of anti-ionized calcium-binding adapter molecule 1 (Iba1) in the iris and ciliary body (ICB) were carried out.

Results

No statistically significant differences existed in the graded score of uveitis and the b-wave peak time in the Dark-adapted 3.0 ERG among the model, N-O, and H-O groups (P>0.05), while rats of the H-O group showed a lower concentration of AqH protein than that of the model or N-O group (P<0.05). The number of the infiltrating cells in the ICB of rats from the H-O group was not significantly different from that of the model or N-O group (P>0.05), while the activation of microglia cells in the H-O group was somewhat reduced (P<0.05).

Conclusions

Post-treatment hydrogen gas inhalation did not ameliorate the clinical signs, or reduce the infiltrating cells of EIU. However, it inhibited the elevation of protein in the AqH and reduced the microglia activation.

Crosslink between lipids and acute uveitis: a lipidomic analysis

AIM

To explore the roles of phospholipids and sphingolipids in the inflammatory process of uveitis.

METHODS

Aqueous humor (AH) and the retina were obtained from endotoxin-induced uveitis (EIU) rats during the acute inflammation stage (24h after endotoxin injection). Lipids were extracted using a modified Bligh and Dyer method and subjected to mass spectrometric identification using class-specific lipid standards and ratiometric quantification. Relative intensity analysis was performed to evaluate the amount change of common lipids between the EIU and control groups.

RESULTS

Unique lipid species encompassing all five phospholipid classes were found in both control and the EIU AH and retina. Commensurate with the significantly increased level of lysophospholipids in the EIU AH and retina, we found that the ratio of lysophospholipids to total phospholipids was significantly increased too. We also detected a significant increase in 18:0 lysophosphatidylcholine levels in the EIU group (fold change =6.4 in AH and 3.8 in retina). Cer240, Cer241, and SM240 levels remarkably increased in the EIU AH. Enhanced C12 ceramide-1-phosphate (C12 C-1-P), C16 C-1-P, C24 C-1-P, and upregulated Cer160, Cer240, SM120, and SM240 were found in EIU retina. C-1-P was believed to restore homeostasis by inhibiting nuclear factor kappa B (NF-κB) activation. However, we still found elevated NF-κB levels in the EIU retina.

CONCLUSION

A variety of lipids might have played a critical role in EIU inflammation. Exogenous topical application of these protective lipids or inhibition of these pro-inflammatory lipids may be useful therapeutic strategies for the resolution of EIU.

[Therapeutic strategy for the treatment of non-infectious uveitis proposed by an expert panel]

Conventional immunosuppressive drugs, anti-TNF alpha and other biotherapies used in clinical practice are capable of controlling non-infectious anterior uveitis, posterior uveitis and panuveitis. The present work has been led by a multidisciplinary panel of experts, internists, rheumatologists and ophthalmologists and is based on a review of the literature. In case of corticodependency or sight-threatening disease, conventional immunosuppressive drugs (methotrexate, azathioprine and mycophenolate mofetil) and/or anti-TNF alpha (adalimumab, infliximab) are used to achieve and maintain remission. Interferon is an efficient immunomodulatory treatment, as a second-line therapy, for some therapeutic indications (refractory macular edema, Behçet's vascularitis). Other biologics, especially tocilizumab, are showing promising results. Local treatments (corticosteroids, sirolimus etc.) are adjuvant therapies in case of unilateral inflammatory relapse. Therapeutic response must be evaluated precisely by clinical examination and repeated complementary investigations (laser flare photometry, multimodal imaging, perimetry, electroretinography measures).

Complement-Mediated Activation of the NLRP3 Inflammasome and Its Inhibition by AAV-Mediated Delivery of CD59 in a Model of Uveitis

Uveitis is an inflammatory disorder of the eye responsible for approximately 10%-15% of blindness in the US. In this study, we examined the role of the complement membrane attack complex (MAC) and the NLRP3 inflammasome in the pathogenesis of experimental autoimmune uveitis (EAU) in normal and C9^-/- mice that are incapable of assembling the MAC. We discovered that the MAC and the NLRP3 inflammasome and associated production of IL-1β are elevated in EAU mice and that MAC may be involved in regulation of Th1 and Th17 cell differentiation. In contrast, MAC and the NLRP3 inflammasome were not elevated in C9^-/- mice. However, EAU-associated pathophysiology including retinal structure and function were not rescued in C9^-/- mice. Unexpectedly, AAV-mediated delivery of sCD59, an inhibitor of C9 incorporation into the MAC, successfully attenuated activation of the NLRP3 inflammasome and EAU pathology as well as MAC. Our studies provide an improved understanding of the role of the MAC and the NLRP3 inflammasome in EAU as well as suggest a novel approach for the treatment of uveitis.