Fulminant bilateral papilloedema during low-dose steroid taper in a child with systemic idiopathic arthritis treated with tocilizumab.

Systemic juvenile idiopathic arthritis (SJIA) is one of the most severe forms of arthritis that affects children younger than 16 years of age at onset. SJIA often requires corticosteroids to control the inflammation. However, long-term corticosteroid use may have adverse effects, including intracranial hypertension (IH). Biologic therapies have been used as corticosteroid sparing agents. We report the first case of a child with steroid-dependent SJIA treated with tocilizumab, an IL-6 receptor monoclonal antibody, who developed fulminant IH, bilateral papilloedema and vision loss when oral prednisone was weaned from 2 to 1 mg per day. Despite repeated lumbar punctures and high dose acetazolamide, he required urgent unilateral optic nerve sheath fenestration (ONSF). This endoscopic surgical intervention released the pressure exerted by the cerebrospinal fluid on the optic nerve and stopped the progression of vision loss. Nine weeks after the diagnosis of bilateral papilloedema, his vision was completely restored in one eye and partially recovered in the contralateral one. Long-term treatment with corticosteroids even at very low dose and tocilizumab may predispose to severe IH, papilloedema and vision loss. The role that tocilizumab might have played in this case in unclear. Early recognition and prompt treatment of papilloedema is crucial in avoiding permanent vision loss. Fulminant papilloedema in an immunocompromised child carries additional significant challenges. Early ONSF is a safe and effective intervention in refractory papilloedema. Children with severe papilledema secondary to IH should be managed by a multidisciplinary team in tertiary centres.

Anti-angiogenic therapeutic strategies in hereditary hemorrhagic telangiectasia.

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular dysplastic disorder, characterized by recurrent nosebleeds (epistaxis), multiple telangiectases and arteriovenous malformations (AVMs) in major organs. Mutations in Endoglin (ENG or CD105) and Activin receptor-like kinase 1 (ACVRL1 or ALK1) genes of the TGF-ß superfamily receptors are responsible for HHT1 and HHT2 respectively and account for the majority of HHT cases. Haploinsufficiency in ENG and ALK1 is recognized at the underlying cause of HHT. However, the mechanisms responsible for the predisposition to and generation of AVMs, the hallmark of this disease, are poorly understood. Recent data suggest that dysregulated angiogenesis contributes to the pathogenesis of HHT and that the vascular endothelial growth factor, VEGF, may be implicated in this disease, by modulating the angiogenic-angiostatic balance in the affected tissues. Hence, anti-angiogenic therapies that target the abnormal vessels and restore the angiogenic-angiostatic balance are candidates for treatment of HHT. Here we review the experimental evidence for dysregulated angiogenesis in HHT, the anti-angiogenic therapeutic strategies used in animal models and some patients with HHT and the potential benefit of the anti-angiogenic treatment for ameliorating this severe, progressive vascular disease.

Impaired resolution of inflammation in the Endoglin heterozygous mouse model of chronic colitis.

Endoglin is a coreceptor of the TGF-ß superfamily predominantly expressed on the vascular endothelium and selective subsets of immune cells. We previously demonstrated that Endoglin heterozygous (Eng (+/-)) mice subjected to dextran sulfate sodium (DSS) developed persistent gut inflammation and pathological angiogenesis. We now report that colitic Eng (+/-) mice have low colonic levels of active TGF-ß1, which was associated with reduced expression of thrombospondin-1, an angiostatic factor known to activate TGF-ß1. We also demonstrate dysregulated expression of BMPER and follistatin, which are extracellular regulators of the TGF-ß superfamily that modulate angiogenesis and inflammation. Heightened colonic levels of the neutrophil chemoattractant and proangiogenic factor, CXCL1, were also observed in DSS-treated Eng (+/-) mice. Interestingly, despite increased macrophage and neutrophil infiltration, a gut-specific reduction in expression of the key phagocytic respiratory burst enzymes, NADPH oxidase 2 (Nox-2) and myeloperoxidase, was seen in Eng (+/-) mice undergoing persistent inflammation. Taken together, these findings suggest that endoglin is required for TGF-ß superfamily mediated resolution of inflammation and fully functional myeloid cells.

Anti-VEGF therapy reduces intestinal inflammation in Endoglin heterozygous mice subjected to experimental colitis.

Chronic intestinal inflammation is associated with pathological angiogenesis that further amplifies the inflammatory response. Vascular endothelial growth factor (VEGF), is a major angiogenic cytokine that has been implicated in chronic colitis and inflammatory bowel diseases. Endoglin (CD105), a transforming growth factor-ß superfamily co-receptor expressed on endothelial and some myeloid cells, is a modulator of angiogenesis involved in wound healing and potentially in resolution of inflammation. We showed previously that Endoglin heterozygous (Eng (+/-)) mice subjected to dextran sodium sulfate developed severe colitis, abnormal colonic vessels and high tissue VEGF. We therefore tested in the current study if treatment with a monoclonal antibody to VEGF could ameliorate chronic colitis in Eng (+/-) mice. Tissue inflammation and microvessel density (MVD) were quantified on histological slides. Colonic wall thickness, microvascular hemodynamics and targeted MAdCAM-1(+) inflamed vessels were assessed in vivo by ultrasound. Mediators of angiogenesis and inflammation were measured by Milliplex and ELISA assays. Colitic Eng (+/-) mice showed an increase in intestinal inflammation, MVD, colonic wall thickness, microvascular hemodynamics and the number of MAdCAM-1(+) microvessels relative to colitic Eng (+/+) mice; these parameters were all attenuated by anti-VEGF treatment. Of all factors up-regulated in the inflamed gut, granulocyte colony-stimulating factor (G-CSF) and amphiregulin were further increased in colitic Eng (+/-) versus Eng (+/+) mice. Anti-VEGF therapy decreased tissue VEGF and inflammation-induced endoglin, IL-1ß and G-CSF in colitic Eng (+/-) mice. Our results suggest that endoglin modulates intestinal angiogenic and inflammatory responses in colitis. Furthermore, contrast-enhanced ultrasound provides an excellent non-invasive imaging modality to monitor gut angiogenesis, inflammation and responses to anti-angiogenic treatment.

Endoglin and activin receptor-like kinase 1 heterozygous mice have a distinct pulmonary and hepatic angiogenic profile and response to anti-VEGF treatment.

Hereditary hemorrhagic telangiectasia (HHT) is a vascular dysplasia associated with dysregulated angiogenesis and arteriovascular malformations. The disease is caused by mutations in endoglin (ENG; HHT1) or activin receptor-like kinase 1 (ALK1; HHT2) genes, coding for transforming growth factor ß (TGF-ß) superfamily receptors. Vascular endothelial growth factor (VEGF) has been implicated in HHT and beneficial effects of anti-VEGF treatment were recently reported in HHT patients. To investigate the systemic angiogenic phenotype of Endoglin and Alk1 mutant mice and their response to anti-VEGF therapy, we assessed microvessel density (MVD) in multiple organs after treatment with an antibody to mouse VEGF or vehicle. Lungs were the only organ showing an angiogenic defect, with reduced peripheral MVD and secondary right ventricular hypertrophy (RVH), yet distinctly associated with a fourfold increase in thrombospondin-1 (TSP-1) in Eng (+/-) versus a rise in angiopoietin-2 (Ang-2) in Alk1 (+/-) mice. Anti-VEGF treatment did reduce lung VEGF levels but interestingly, led to an increase in peripheral pulmonary MVD and attenuation of RVH; it also normalized TSP-1 and Ang-2 expression. Hepatic MVD, unaffected in mutant mice, was reduced by anti-VEGF therapy in heterozygous and wild type mice, indicating a liver-specific effect of treatment. Contrast-enhanced micro-ultrasound demonstrated a reduction in hepatic microvascular perfusion after anti-VEGF treatment only in Eng (+/-) mice. Our findings indicate that the mechanisms responsible for the angiogenic imbalance and the response to anti-VEGF therapy differ between Eng and Alk1 heterozygous mice and raise the need for systemic monitoring of anti-angiogenic therapy effects in HHT patients.

Severe ulcerative colitis after rituximab therapy.

B-cell-depletion therapy with rituximab is efficacious against steroid-dependent nephrotic syndrome (NS) in children and adults. Safety data are limited. Results of small studies have suggested that rituximab is usually well tolerated but that adverse events (such as severe mucocutaneous reactions, fatal infusion reactions, progressive multifocal leukoencephalopathy, and bowel perforation) can occur. We report here the first case (to our knowledge) of a pediatric patient with refractory minimal-change NS who developed severe immune-mediated ulcerative gastrointestinal disease 42 days after rituximab therapy. The disease was characterized by deep ulcers throughout the intestines and predominantly affected the colon. The child presented with severe abdominal pain, bloody diarrhea, weight loss, and fever. Her inflammatory markers were significantly elevated. Extensive evaluation revealed no evidence of infections and no characteristics of defined inflammatory bowel disease or Behçet disease. Colonoscopy revealed severe intestinal inflammation with deep ulcers. Histology of the colonic biopsy specimens revealed extensive infiltrates predominantly composed of CD8(+) T lymphocytes and evidence of high forkhead box P3 (FOXP3) expression. During this significant gastrointestinal disease, the NS remained quiescent. Corticosteroid therapy successfully controlled the severe immune-mediated intestinal inflammation after rituximab therapy. NS relapsed subsequently when CD19(+) and CD20(+) B-cell populations recovered.