Biologic agents in the management of inflammatory eye diseases

Therapeutic Potential of Exosomes Derived from Adipose Tissue-Sourced Mesenchymal Stem Cells in the Treatment of Neural and Retinal Diseases

Therapeutic agents that are able to prevent or attenuate inflammation and ischemia-induced injury of neural and retinal cells could be used for the treatment of neural and retinal diseases. Exosomes derived from adipose tissue-sourced mesenchymal stem cells (AT-MSC-Exos) are extracellular vesicles that contain neurotrophins, immunoregulatory and angio-modulatory factors secreted by their parental cells. AT-MSC-Exos are enriched with bioactive molecules (microRNAs (miRNAs), enzymes, cytokines, chemokines, immunoregulatory, trophic, and growth factors), that alleviate inflammation and promote the survival of injured cells in neural and retinal tissues. Due to the nano-sized dimension and bilayer lipid envelope, AT-MSC-Exos easily bypass blood–brain and blood–retinal barriers and deliver their cargo directly into the target cells. Accordingly, a large number of experimental studies demonstrated the beneficial effects of AT-MSC-Exos in the treatment of neural and retinal diseases. By delivering neurotrophins, AT-MSC-Exos prevent apoptosis of injured neurons and retinal cells and promote neuritogenesis. AT-MSC-Exos alleviate inflammation in the injured brain, spinal cord, and retinas by delivering immunoregulatory factors in immune cells, suppressing their inflammatory properties. AT-MSC-Exos may act as biological mediators that deliver pro-angiogenic miRNAs in endothelial cells, enabling re-vascularization of ischemic neural and retinal tissues. Herewith, we summarized current knowledge about molecular mechanisms which were responsible for the beneficial effects of AT-MSC-Exos in the treatment of neural and retinal diseases, emphasizing their therapeutic potential in neurology and ophthalmology.

Clinical Presentation, Management, and Long-Term Outcome of Pars Planitis, Panuveitis, and Vogt-Koyanagi-Harada Disease in Children and Adolescents

OBJECTIVE

Chronic uveitis is a common manifestation of pediatric rheumatologic conditions and may result in irreversible blindness and long-term disability. While chronic anterior uveitis is the most commonly encountered ocular manifestation of rheumatic disease, little is known about the clinical presentation, management, and long-term outcome of more complex eye conditions such as pars planitis (PP), panuveitis (PU), and Vogt-Koyanagi-Harada disease (VKH). The present study was undertaken to comprehensively assess the long-term safety and efficacy of disease-modifying antirheumatic drugs (DMARDs) and biologics for the treatment of pediatric and adolescent patients with PP, PU, and VKH.

METHODS

We retrospectively reviewed a cohort of 75 children and adolescents with idiopathic PP (n = 50), PU (n = 12), and VKH (n = 14) followed by the Pediatric Rheumatology Core at Children's Hospital Los Angeles and evaluated referral patterns, clinical presentation, treatment response, and long-term clinical outcome.

RESULTS

Patients were followed for an average of 52 months. Their mean age at disease onset was 10 years. Bilateral eye involvement was seen in 87% of the patients. At first presentation to an ophthalmologist, glaucoma was noted in 21% of patients and vision loss (<20/40) in 87% of patients, while legal blindness (≤20/200 in the better-seeing eye) was diagnosed in 18 of 75 (24%) of patients (PP 22%, PU 36%, and VKH 21%). The average referral time to a pediatric rheumatologist was 13 months (range 1-96 months). Topical steroids were used in all patients, but 98% of patients required additional DMARDs, and 73% required therapy with biologics. After a mean of 52 months, 35% of patients across all disease groups had significant vision loss or were blind, and only 28% were in clinical remission without medications. The worst outcome was observed in children with PU. Regression analysis, young age at onset, delayed referral to a pediatric rheumatologist, and chronic disease were strong predictors for the risk of long-term blindness.

CONCLUSION

PP, PU, and VKH involve a high risk of permanent vision loss and should be managed by a skilled rheumatologist as early and as aggressively as possible.

UV light-blocking contact lenses protect against short-term UVB-induced limbal stem cell niche damage and inflammation

UVB irradiation has been linked to pathogenesis of pterygium, a conjunctival tumor growing onto transparent cornea, the windscreen of the eye. Due to corneal anatomy, ambient UVB irradiation is amplified at the stem cell-containing nasal limbus. The aim of this study was to analyse the effect of a UV-blocking contact lens (UVBCL, senofilcon A, Class 1 UV blocker) on limbal epithelial cells and fibroblasts under UVB irradiation compared to a non-UVB-blocking contact lens. UVBCL prevented UVB-induced DNA damage (as assessed by cyclobutane pyrimidine dimer immunostaining) as well as a decrease in proliferation and scratch wound closure rate of both limbal epithelial and fibroblast cells. Similarly, UVBCL protected limbal epithelial cells from UVB-induced loss of their phenotype in terms of colony forming efficiency and stem cell marker expression (ABCB5, P63α, integrin β1) compared to controls. Moreover, with UVBCL pro-inflammatory cytokines such as TNFα and MCP1 remained unchanged. These data demonstrate the significance of UV-protection in preserving the limbal niche in response to at least short-term UVB. Our data support the use of UVBCL in protecting limbal niche cells, especially after limbal stem cell transplantation and in patients after pterygium surgery, to help prevent recurrences.

The Role of Limbal Epithelial Stem Cells in Regulating Corneal (Lymph)angiogenic Privilege and the Micromilieu of the Limbal Niche following UV Exposure

The cornea is a clear structure, void of blood, and lymphatic vessels, functioning as our window to the world. Limbal epithelial stem cells, occupying the area between avascular cornea and vascularized conjunctiva, have been implicated in tissue border maintenance, preventing conjunctivalisation and propagation of blood and lymphatic vessels into the cornea. Defects in limbal epithelial stem cells are linked to corneal neovascularisation, including lymphangiogenesis, chronic inflammation, conjunctivalisation, epithelial abnormalities including the presence of goblet cells, breaks in Bowman's membrane, persistent epithelial defects and ulceration, ocular surface squamous neoplasia, lipid keratopathy, pain, discomfort, and compromised vision. It has been postulated that pterygium is an example of focal limbal deficiency. Previous reports showing changes occurring in limbal epithelium during pterygium pathogenesis suggest that there is a link to stem cell damage. In this light, pterygium can serve as a model disease of UV-induced stem cell damage also characterised by corneal blood and lymphangiogenesis. This review focuses on the role of corneal and limbal epithelial cells and the stem cell niche in maintaining corneal avascularity and corneal immune privilege and how this may be deregulated following UV exposure. We present an overview of the PUBMED literature in the field as well as recent work from our laboratories.

Anti-angiogenic effect of a humanized antibody blocking the Wnt/β-catenin signaling pathway

PURPOSE

Our previous study demonstrated that Mab2F1, a murine monoclonal antibody blocking the Wnt/β-catenin signaling pathway, has beneficial effects on experimental diabetic retinopathy and choroidal neovascularization (NV). The aforementioned antibody has been humanized. This study evaluated effects of the humanized antibody, H1L1, on NV.

METHODS

H1L1 was evaluated in the alkali burn-induced corneal NV rat model. Rats with corneal NV were injected subconjunctivally with Mab2F1 or H1L1 using non-specific mouse or human IgG as controls. Corneal NV and opacity were evaluated using corneal NV area and inflammatory index. Expression of angiogenic and inflammatory factors and components of the Wnt/β-catenin pathway in both the corneas of the animal model and human corneal epithelial (HCE) cells exposed to Wnt3a conditioned medium (WCM) were determined by Western blotting and a luciferase-based promoter assay. Cytotoxicities of these antibodies were evaluated by MTT assay.

RESULTS

H1L1 reduced the area of corneal NV and opacity, similar to Mab2F1. Both Mab2F1 and H1L1 down-regulated the overexpression of angiogenic and inflammatory factors including VEGF, TNF-α and ICAM-1, and blocked the aberrant activation of the Wnt/β-catenin pathway as shown by down-regulation of phosphorylated LRP6, total LRP6 and non-phosphorylated β-catenin in the cornea of the NV model and cultured HCE cells exposed to WCM. Both antibodies also inhibited the transcriptional activity of β-catenin induced by WCM in HCE cells. No toxic effects of the antibodies were observed in cultured HCE cells.

CONCLUSIONS

H1L1 exhibits anti-angiogenic activities through blocking the Wnt/β-catenin pathway.

Adalimumab for Ocular Inflammation

PURPOSE

To evaluate adalimumab as an immunomodulatory treatment for non-infectious ocular inflammatory diseases.

METHODS

Characteristics of patients treated with adalimumab were abstracted in a standardized chart review. Main outcomes measured were control of inflammation, corticosteroid-sparing effect, and visual acuity.

RESULTS

In total, 32 patients with ocular inflammation were treated with adalimumab. The most common ophthalmic diagnoses were anterior uveitis, occurring in 15 patients (47%), and scleritis, occurring in 9 patients (28%). At 6 months of therapy, among 15 eyes with active inflammation, 7 (47%) became completely inactive, and oral prednisone was reduced to ≤10 mg/day in 2 of 4 patients (50%). On average, visual acuity decreased by 0.13 lines during the first 6 months of treatment. Adalimumab was discontinued because of lack of effectiveness in four patients within 6 months.

CONCLUSIONS

Adalimumab was moderately effective in controlling inflammation in a group of highly pre-treated cases of ocular inflammatory disease.

Biologic agents in experimental autoimmune uveitis

Experimental uveitis models were developed in an effort to elucidate the pathogenesis of human uveitis. The therapeutic effects of numerous anti-inflammatory agents including corticosteroids and immunomodulatory agents including biologic response modifiers have been investigated in both experimental and human uveitis. Monoclonal antibodies to tumor necrosis factor alpha and anti-interleukins, among others, demonstrate efficacy and are employed in the treatment of uveitis refractory to conventional immunomodulatory agents.

Anti-angiogenic and anti-inflammatory effects of SERPINA3K on corneal injury

SERPINA3K is a member of the serine proteinase inhibitor (SERPIN) family. Here we evaluated the therapeutic effects of SERPINA3K on neovascularization and inflammation in a rat cornea alkali burn model that is commonly employed to study corneal wounding. Topical treatment of the injured rat cornea with SERPINA3K (20 µg/eye/day) for 7 days significantly decreased the neovascular area, compared with the groups treated with BSA or PBS. The SERPINA3K treatment also ameliorated the corneal inflammation as evaluated by the inflammatory index. Furthermore, SERPINA3K enhanced the recovery of corneal epithelium after the alkali injury. Toward the mechanism of action, SERPINA3K down-regulated the expression of the pro-angiogenic and pro-inflammatory factors, vascular endothelial growth factor and tumor necrosis factor-α and up-regulated the expression of the anti-angiogenic factor, pigment epithelium-derived factor. SERPINA3K specifically inhibited growth of vascular endothelial cells. Meanwhile, SERPINA3K significantly up-regulated the expression of EGFR in the corneal epithelium. These findings suggest that SERPINA3K has therapeutic potential for corneal inflammation and NV.

Extraintestinal manifestations of inflammatory bowel disease: epidemiology, diagnosis, and management

Abstract Extraintestinal manifestations occur rather frequently in inflammatory bowel disease (IBD), e.g. ulcerative colitis (UC) and Crohn's disease (CD). The present paper provides an overview of the epidemiology, clinical characteristics, diagnostic process, and management of rheumatic, metabolic, dermatologic (mucocutaneous), ophthalmologic, hepatobiliary, hematologic, thromboembolic, urinary tract, pulmonary, and pancreatic extraintestinal manifestations related to IBD. Articles were identified through search of the PubMed and Embase databases, the Cochrane Library, and the web sites of the European Agency for the Evaluation of Medicinal Products (EMEA) and the US Food and Drug Administration (FDA) (cut-off date October 2009). The search terms 'Crohn's disease', 'inflammatory bowel disease', or 'ulcerative colitis' were combined with the terms 'adalimumab', 'anemia', 'arthritis', 'bronchiectasis', 'bronchitis', 'cutaneous manifestations', 'erythema nodosum', 'extraintestinal manifestations', 'hyperhomocysteinemia', 'infliximab', 'iridocyclitis', 'lung disease', 'ocular manifestations', 'osteomalacia', 'pancreatitis', 'primary sclerosing cholangitis', 'renal stones', 'sulfasalazine', 'thromboembolism', and 'treatment'. The search was performed on English-language reviews, practical guidelines, letters, and editorials. Articles were selected based on their relevance, and additional papers were retrieved from their reference lists. Since some of the diseases discussed are uncommon, valid evidence of treatment was difficult to obtain, and epidemiologic data on the rarer forms of extraintestinal manifestations are scarce. However, updates on the pathophysiology and treatment regimens are given for each of these disorders. This paper offers a current review of original research papers and randomized clinical trials, if any, within the field and makes an attempt to point out practical guidelines for the diagnosis and treatment of various extraintestinal manifestations related to IBD.