Incidence of uveitis and macular edema among patients taking fingolimod 0.5 mg for multiple sclerosis

Sphingosine 1-phosphate, a potential target in neovascular retinal disease

Neovascular ocular diseases (such as age-related macular degeneration, diabetic retinopathy and retinal vein occlusion) are characterised by common pathological processes that contribute to disease progression. These include angiogenesis, oedema, inflammation, cell death and fibrosis. Currently available therapies target the effects of vascular endothelial growth factor (VEGF), the main mediator of pathological angiogenesis. Unfortunately, VEGF blockers are expensive biological therapeutics that necessitate frequent intravitreal administration and are associated with multiple adverse effects. Thus, alternative treatment options associated with fewer side effects are required for disease management. This review introduces sphingosine 1-phosphate (S1P) as a potential pharmacological target for the treatment of neovascular ocular pathologies. S1P is a sphingolipid mediator that controls cellular growth, differentiation, survival and death. S1P actions are mediated by five G protein-coupled receptors (S1P_1-5 receptors) which are abundantly expressed in all retinal and subretinal structures. The action of S1P on S1P₁ receptors can reduce angiogenesis, increase endothelium integrity, reduce photoreceptor apoptosis and protect the retina against neurodegeneration. Conversely, S1P₂ receptor signalling can increase neovascularisation, disrupt endothelial junctions, stimulate VEGF release, and induce retinal cell apoptosis and degeneration of neural retina. The aim of this review is to thoroughly discuss the role of S1P and its different receptor subtypes in angiogenesis, inflammation, apoptosis and fibrosis in order to determine which of these S1P-mediated processes may be targeted therapeutically.

Non-vasogenic cystoid maculopathies

Besides cystoid macular edema due to a blood-retinal barrier breakdown, another type of macular cystoid spaces referred to as non-vasogenic cystoid maculopathies (NVCM) may be detected on optical coherence tomography but not on fluorescein angiography. Various causes may disrupt retinal cell cohesion or impair retinal pigment epithelium (RPE) and Müller cell functions in the maintenance of retinal dehydration, resulting in cystoid spaces formation. Tractional causes include vitreomacular traction, epiretinal membranes and myopic foveoschisis. Surgical treatment does not always allow cystoid space resorption. In inherited retinal dystrophies, cystoid spaces may be part of the disease as in X-linked retinoschisis or enhanced S-cone syndrome, or occur occasionally as in bestrophinopathies, retinitis pigmentosa and allied diseases, congenital microphthalmia, choroideremia, gyrate atrophy and Bietti crystalline dystrophy. In macular telangiectasia type 2, cystoid spaces and cavitations do not depend on the fluid leakage from telangiectasia. Various causes affecting RPE function may result in NVCM such as chronic central serous chorioretinopathy and paraneoplastic syndromes. Non-exudative age macular degeneration may also be complicated by intraretinal cystoid spaces in the absence of fluorescein leakage. In these diseases, cystoid spaces occur in a context of retinal cell loss. Various causes of optic atrophy, including open-angle glaucoma, result in microcystoid spaces in the inner nuclear layer due to a retrograde transsynaptic degeneration. Lastly, drug toxicity may also induce cystoid maculopathy. Identifying NVCM on multimodal imaging, including fluorescein angiography if needed, allows guiding the diagnosis of the causative disease and choosing adequate treatment when available.

Diagnosis and Management of Fingolimod-Associated Macular Edema

Objective

To investigate the clinical features, treatment, and prognosis of fingolimod-associated macular edema (FAME) and to provide a reference for its rational management.

Methods

FAME-related case reports were included in a pooled analysis by searching Chinese and English databases from 2010 to November 31, 2021.

Results

The median age of 41 patients was 50 years (range, 21, 67 years), of whom 32 were women. The median time to onset of FAME was 3 m (range.03, 120), and blurred vision (17 cases) and decreased vision (13 cases) were the most common complaints. A total of 55 eyes were involved in FAME, including the left eye (14 cases), right eye (10 cases), and both eyes (15 cases), of which 46 eyes had best-corrected visual acuity close to normal (20/12-20/60) and 8 eyes had moderate to severe visual impairment (20/80-20/500). Fundus examination in 23 patients showed macular edema (11 cases). Optical coherence tomography (OCT) in 39 patients mainly showed perifoveal cysts (24 cases), ME (23 cases), and foveal thickening (19 cases). Fundus fluorescein angiography (FFA) in 18 patients showed vascular leakage (11 cases). Complete resolution of ME occurred in 50 eyes and recovery of visual acuity occurred in 45 eyes at a median time of 2 m (range 0.25, 24) after discontinuation of fingolimod or administration of topical therapy.

Conclusions

Macular edema is a known complication of fingolimod. All patients using fingolimod require regular eye exams, especially those with a history of diabetes and uveitis and those undergoing cataract surgery.

Indications and effects of biological agents in the treatment of noninfectious uveitis

Noninfectious uveitis is a common blinding eye disease, and an autoimmune response is involved in its pathogenesis. Biological agents have gradually been introduced into the treatment of noninfectious uveitis. The authors reviewed the clinical application and side effects of different biological agents on noninfectious uveitis. Biological agents that target TNF-α are widely used in the clinic. Other biological agents, such as IL-6- and IL-1-neutralizing antibodies, are used in patients who do not respond to TNF inhibitors. The efficacy of IL-17 neutralizing antibodies in noninfectious uveitis is controversial. Biological agents targeting T cells and signaling pathways provide new drug options for treatment of noninfectious uveitis. However, it cannot be ignored that these biological agents have side effects, such as increasing risk of infection.