RESUMO
Patients who harbor brain arteriovenous malformations are at risk for intracranial hemorrhage. These malformations are often seen in inherited vascular diseases such as hereditary hemorrhagic telangiectasia. However, malformations within the brain also sporadically occur without a hereditary-coding component. Here, we review recent insights into the pathophysiology of arteriovenous malformations, in particular, certain signaling pathways that might underlie endothelial cell pathology. To better interpret the origins, determinants and consequences of brain arteriovenous malformations, we present a clinical case to illustrate the phenotypic landscape of the disease. We also propose that brain arteriovenous malformations might share certain signaling dimensions with those of anorectal hemorrhoids. This working hypothesis provides casual anchors from which to understand vascular diseases characterized by arteriovenous lesions with a hemorrhagic- or bleeding-risk component. Anat Rec, 2017. © The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists. Anat Rec, 300:1973-1980, 2017. © 2017 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.
Assuntos
Fístula Arteriovenosa/patologia , Encéfalo/irrigação sanguínea , Células Endoteliais/patologia , Malformações Arteriovenosas Intracranianas/patologia , Transdução de Sinais/genética , Telangiectasia Hemorrágica Hereditária/patologia , Receptores de Activinas Tipo II/genética , Receptores de Activinas Tipo II/metabolismo , Adulto , Fístula Arteriovenosa/diagnóstico por imagem , Fístula Arteriovenosa/dietoterapia , Fístula Arteriovenosa/genética , Pressão Sanguínea , Encéfalo/diagnóstico por imagem , Fibras na Dieta/uso terapêutico , Endoglina/genética , Endoglina/metabolismo , Humanos , Malformações Arteriovenosas Intracranianas/diagnóstico por imagem , Malformações Arteriovenosas Intracranianas/dietoterapia , Malformações Arteriovenosas Intracranianas/genética , Angiografia por Ressonância Magnética , Masculino , Mutação , Telangiectasia Hemorrágica Hereditária/dietoterapia , Telangiectasia Hemorrágica Hereditária/genética , Tomografia Computadorizada por Raios X , Fator de Crescimento Transformador beta/metabolismoRESUMO
PURPOSE: To analyze macular pigment (MP) amount and distribution in patients with macular telangiectasia Type 2 receiving oral zeaxanthin supplementation in a randomized, open-label, interventional trial. METHODS: Eight macular telangiectasia Type 2 patients were randomized to 10 mg or 20 mg of zeaxanthin per day. At each visit, best-corrected visual acuity, contrast sensitivity, fundus biomicroscopy, color fundus photography, autofluorescence imaging, optical coherence tomography, and serum carotenoid levels were tested. Patients were assessed at baseline and after 6, 12, 18, and 24 months of zeaxanthin supplementation. Concentration of MP was analyzed and calculated from autofluorescence imaging obtained at 488-nm excitation wavelength. Serum carotenoid levels were obtained using high-performance liquid chromatography. RESULTS: The majority of patients had definite increases in the intensity of hypofluorescent ring of MP, but none of them deposited MP centrally at the fovea. Although some patients noted subjective improvements in vision, no objective improvements could be documented, and there were no changes in foveal optical coherence tomographic features. Yellowish, hypofluorescent crystals appeared in one patient's macular region with no change in visual acuity. These inner retinal crystals disappeared several months after discontinuing her 20-mg zeaxanthin supplement. CONCLUSION: Based on the current study, zeaxanthin supplementation does not result in any visual benefit in patients with macular telangiectasia Type 2 and does not reestablish a normal peaked distribution of MP in the fovea. One patient developed a novel, reversible, crystalline maculopathy in response to zeaxanthin supplementation that was reminiscent of canthaxanthin crystalline maculopathy.
