Tubulointerstitial nephritis and uveitis in children and adolescents

 We identified 35 cases of tubulointerstitial nephritis and uveitis (TINU), 31 from a MEDLINE search (1966–1996) of the English literature and 4 from our hospital records (1988–1996). To meet the case definition, the patient had to be less than 18 years old and have TINU of unknown cause. Common presenting symptoms included fatigue, weight loss, fever, and abdominal pain. The uveitis was usually anterior and could occur at any time with respect to the onset of the renal disease. Common laboratory features included anemia, increased erythrocyte sedimentation rate, and decreased creatinine clearance. Most patients (33 of 35) had renal biopsies that commonly revealed an intense inflammatory interstitial infiltrate, glomerular sparing, and negative immunofluorescence studies. Of the 35 patients, 26 received systemic corticosteroid therapy (5 of 26 for eye disease); 22 had follow-up for at least 1 year; 13 of 35 patients had a recurrence of their uveitis. The outcome in all 35 cases was normal renal function with no documented visual loss. In conclusion, TINU is a unique syndrome with characteristic clinical features, laboratory changes, and renal biopsy results. Treatment is controversial, and the outcome in children, even if untreated, is excellent. Received: 21 May 1998 / Revised: 22 September 1998 / Accepted: 23 September 1998     

French recommendations for the management of non-infectious chronic uveitis

This French National Diagnostic and Care Protocol (NDPC) includes both pediatric and adult patients with non-infectious chronic uveitis (NICU) or non-infectious recurrent uveitis (NIRU). NICU is defined as uveitis that persists for at least 3 months or with frequent relapses occurring less than 3 months after cessation of treatment. NIRU is repeated episodes of uveitis separated by periods of inactivity of at least 3 months in the absence of treatment. Some of these NICU and NIRU are isolated. Others are associated with diseases that may affect various organs, such as uveitis associated with certain types of juvenile idiopathic arthritis, adult spondyloarthropathies or systemic diseases in children and adults such as Behçet's disease, granulomatoses or multiple sclerosis. The differential diagnoses of pseudo-uveitis, sometimes related to neoplasia, and uveitis of infectious origin are discussed, as well as the different forms of uveitis according to their main anatomical location (anterior, intermediate, posterior or panuveitis). We also describe the symptoms, known physiopathological mechanisms, useful complementary ophthalmological and extra-ophthalmological examinations, therapeutic management, monitoring and useful information on the risks associated with the disease or treatment. Finally, this protocol presents more general information on the care pathway, the professionals involved, patient associations, adaptations in the school or professional environment and other measures that may be implemented to manage the repercussions of these chronic diseases. Because local or systemic corticosteroids are usually necessary, these treatments and the risks associated with their prolonged use are the subject of particular attention and specific recommendations. The same information is provided for systemic immunomodulatory treatments, immunosuppressive drugs, sometimes including anti-TNFα antibodies or other biotherapies. Certain particularly important recommendations for patient management are highlighted in summary tables.     

The multifunctional human ocular melanocortin system

Immune privilege in the eye involves physical barriers, immune regulation and secreted proteins that together limit the damaging effects of intraocular immune responses and inflammation. The neuropeptide alpha-melanocyte stimulating hormone (α-MSH) normally circulates in the aqueous humour of the anterior chamber and the vitreous fluid, secreted by iris and ciliary epithelium, and retinal pigment epithelium (RPE). α-MSH plays an important role in maintaining ocular immune privilege by helping the development of suppressor immune cells and by activating regulatory T-cells. α-MSH functions by binding to and activating melanocortin receptors (MC1R to MC5R) and receptor accessory proteins (MRAPs) that work in concert with antagonists, otherwise known as the melanocortin system. As well as controlling immune responses and inflammation, a broad range of biological functions is increasingly recognised to be orchestrated by the melanocortin system within ocular tissues. This includes maintaining corneal transparency and immune privilege by limiting corneal (lymph)angiogenesis, sustaining corneal epithelial integrity, protecting corneal endothelium and potentially enhancing corneal graft survival, regulating aqueous tear secretion with implications for dry eye disease, facilitating retinal homeostasis via maintaining blood-retinal barriers, providing neuroprotection in the retina, and controlling abnormal new vessel growth in the choroid and retina. The role of melanocortin signalling in uveal melanocyte melanogenesis however remains unclear compared to its established role in skin melanogenesis. The early application of a melanocortin agonist to downregulate systemic inflammation used adrenocorticotropic hormone (ACTH)-based repository cortisone injection (RCI), but adverse side effects including hypertension, edema, and weight gain, related to increased adrenal gland corticosteroid production, impacted clinical uptake. Compared to ACTH, melanocortin peptides that target MC1R, MC3R, MC4R and/or MC5R, but not adrenal gland MC2R, induce minimal corticosteroid production with fewer adverse systemic effects. Pharmacological advances in synthesising MCR-specific targeted peptides provide further opportunities for treating ocular (and systemic) inflammatory diseases. Following from these observations and a renewed clinical and pharmacological interest in the diverse biological roles of the melanocortin system, this review highlights the physiological and disease-related involvement of this system within human eye tissues. We also review the emerging benefits and versatility of melanocortin receptor targeted peptides as non-steroidal alternatives for inflammatory eye diseases such as non-infectious uveitis and dry eye disease, and translational applications in promoting ocular homeostasis, for example, in corneal transplantation and diabetic retinopathy.     

The role of the gut microbiome in eye diseases

The gut microbiome is a complex ecosystem of microorganisms and their genetic entities colonizing the gastrointestinal tract. When in balanced composition, the gut microbiome is in symbiotic interaction with its host and maintains intestinal homeostasis. It is involved in essential functions such as nutrient metabolism, inhibition of pathogens and regulation of immune function. Through translocation of microbes and their metabolites along the epithelial barrier, microbial dysbiosis induces systemic inflammation that may lead to tissue destruction and promote the onset of various diseases. Using whole-metagenome shotgun sequencing, several studies have shown that the composition and associated functional capacities of the gut microbiome are associated with age-related macular degeneration, retinal artery occlusion, central serous chorioretinopathy and uveitis. In this review, we provide an overview of the current knowledge about the gut microbiome in eye diseases, with a focus on interactions between the microbiome, specific microbial-derived metabolites and the immune system. We explain how these interactions may be involved in the pathogenesis of age-related macular degeneration, retinal artery occlusion, central serous chorioretinopathy and uveitis and guide the development of new therapeutic approaches by microbiome-altering interventions for these diseases.