Gene/Protein Disease Symptom Drug Enzyme Compound
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 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exfoliation syndrome (XFS) is an age-related disease in which abnormal fibrillar extracellular material is produced and accumulates in many ocular tissues. Its ocular manifestations involve all of the structures of the anterior segment, as well as conjunctiva and orbital structures. Glaucoma occurs more commonly in eyes with XFS than in those without it; in fact, XFS has recently been recognized as the most common identifiable cause of glaucoma. Patients with XFS are also predisposed to develop angle-closure glaucoma, and glaucoma in XFS has a more serious clinical course and worse prognosis than primary open-angle glaucoma. There is increasing evidence for an etiological association of XFS with cataract formation, and possibly with retinal vein occlusion. XFS is now suspected to be a systemic disorder and has been associated preliminarily with transient ischemic attacks, stroke, systemic hypertension, and myocardial infarction. Further ramifications await discovery. Deposits of white material on the anterior lens surface are the most consistent and important diagnostic feature of XFS. The classic pattern consists of three distinct zones that become visible when the pupil is fully dilated. Whereas the classic picture of manifest XFS has been often described, the early stages of beginning exfoliation have not been well defined. Next to the lens, exfoliation material is most prominent at the pupillary border. Pigment loss from the iris sphincter region and its deposition on anterior chamber structures is a hallmark of XFS. Despite extensive research, the exact chemical composition of exfoliation material (XFM) remains unknown. An overproduction and abnormal metabolism of glycosaminoglycans have been suggested as one of the key changes in XFS. The protein components of XFM include both noncollagenous basement membrane components and epitopes of the elastic fiber system such as fibrillium. Regardless of etiology, typical exfoliation fibers have been demonstrated electron microscopically in close association with the pre-equatorial lens epithelium, the nonpigmented ciliary epithelium, the iris pigment epithelium, the corneal endothelium, the trabecular endothelium, and with almost all cell types of the iris stroma, such as fibrocytes, melanocytes, vascular endothelial cells, pericytes, and smooth muscle cells. The presence of XFS should alert the physician to the increased risks of intraocular surgery, most commonly zonular dehiscence, capsular rupture, and vitreous loss during cataract extraction. Heightened awareness of this condition and its associated clinical signs are important in the detection and management of glaucoma, and preoperative determination of those patients at increased risk for surgical complications.
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PMID:Exfoliation syndrome. 1116 42

Exfoliation syndrome (XFS) is a systemic condition. Intraocular alterations represent only a part of the exfoliation-related clinical signs. Exfoliation material has been identified in the visceral organs, skin, and vessel walls. This triggered several studies that investigated association between XFS and cardiovascular diseases. In many populations, significant associations between XFS and various systemic vascular diseases including elevated plasma homocysteine level, myocardial dysfunction, stroke, aortic aneurysm, and white matter lesions were found. Some of these XFS-associated vascular diseases are caused by elastosis of the vessel wall, which may be directly related to general extracellular dysfunction in XFS. Another part of the pathologic vascular alterations (reduced cutaneous capillary flow reactions, impaired baroreflex sensitivity, parasympathetic cardiovascular neuropathy, and pathologic heart rate variability indices), however, suggests that vascular dysregulation beyond the age-related normal decline may also play a role both in the development and worsening of the systemic cardiovascular diseases in XFS. The exact mechanism of the development of systemic vascular dysregulation associated with XFS is currently unknown.
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PMID:Exfoliation syndrome and systemic cardiovascular diseases. 2527 16

Both exfoliation syndrome (XFS) and exfoliation glaucoma (XFG) are associated with systemic vascular diseases and abnormalities. Although no uniform relationship between XFS/XFG and clinical systemic vascular diseases has been established across various populations, vascular dysfunction with or without clinically significant consequences has been repeatedly detected with both epidemiological and pathophysiological methods. Elevated plasma homocysteine, reduced cutaneous capillary flow reactions, damaged conduit artery dysfunction, impaired baroreflex sensitivity, parasympathetic cardiovascular neuropathy, and pathologic heart rate variability indices have all been shown in XFS and XFG. These pathophysiological alterations exceed the normal age-dependent decline and are considered strongly related to systemic elastosis and increased oxidative stress, but are not direct consequences of the presence of the risk alleles of the lysyl oxydase-like 1 gene. The mechanisms of the development of the clinically significant consequences (eg, increased frequency of myocardial dysfunction, stroke, aorta aneurism, and white matter lesions) are only partially understood. The current knowledge on vascular dysfunction in XFS/XFG is summarized in this article.
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PMID:Vascular Dysfunction in Exfoliation Syndrome. 2941 48