Etiological mechanism of iridocorneal endothelial (ICE) syndrome may involve infection of herpes simplex virus (HSV) and integration of viral genes into human genome.

Iridocorneal (ICE) syndrome is a rare ocular disease characterized by abnormal proliferation of corneal endothelial cells, progressive obstruction of irido-corneal angle and atrophy of iris. ICE syndrome progressed slowly, but can cause serious complications such as secondary glaucoma in late stage. Because the etiology of ICE syndrome is not clear, there is still no effective treatment in clinical practice. Previous studies have detected herpes simplex virus (HSV) DNA inside patient's aqueous humor. However, no further explanation for HSV-related etiology of ICE syndrome was established. Besides, construction of animal models using HSV all failed, leaving behind a blank space about how HSV infection finally led to ICE syndrome. By summarizing findings from previous studies, we came up with a hypothesis about etiology of ICE syndrome: HSV infection initiated ICE syndrome by integration of viral genetic material into human genome. Infection of HSV changed activity and morphology of endothelial cells, making them regain the ability of mitosis. Proof of such hypothesis will provide a theoretical foundation for construction of animal models and effective intervention of the disease.

The iridocorneal endothelial syndrome.

The iridocorneal endothelial syndrome represents a unique group of ocular pathologies (Chandler syndrome, progressive iris atrophy, and Cogan-Reese syndrome) characterized by the proliferation of corneal endothelial cells that migrate toward the iridocorneal angle and iris surface causing, to a degree varying according to the subtype, corneal edema and decompensation and secondary glaucoma, whether by obstructing the angle or producing peripheral anterior synechiae by contraction of the basement membrane of the migrating cells over the surface of the iris. A triggering factor, possibly viral, induces the corneal endothelial cells to proliferate and behave like epithelial cells. Diagnosis is made based on typical ocular findings on the cornea and iris. Iridocorneal endothelial syndrome is more frequent in young women, with unilateral involvement in most cases. In vivo confocal microscopy is an excellent diagnostic tool, especially in borderline presentations like early cases of Chandler syndrome, which affects the cornea predominantly. Typical clinical management consists of treating the corneal edema and decompensation, where endothelial keratoplasty techniques have replaced in many cases the need for a penetrating keratoplasty and treating the secondary glaucoma, which usually requires surgical intervention.

[The irido-corneo-endothelial syndrome. The loss of the control of corneal endothelial cell cycle. A review]. / Le syndrome irido-cornéo-endothélial ou la perte du contrôle du cycle cellulaire de l'endothélium cornéen. Une revue.

The three major symptoms of the irido-corneo-endothelial syndrome are the alterations of the corneal endothelium and of the iris with a loss of the regulation of the cell cycle, and the progressive obstruction of the irido-corneal angle. This rare pathology attacks mainly young adult women. Most of the symptoms and complications originate from the excessive proliferation of the corneal endothelial cells accompanied by the evolution of their phenotype towards that of the epithelial cells. In normal conditions the corneal endothelial cells do not divide, they are blocked in the G1 stage of the cell cycle, mainly because of the action of the inhibitors of cyclin-dependent kinases. Still these cells retain a good capacity for proliferation, which can be induced by the down-regulation of the expression of the inhibitors of the cyclin-dependent kinases. This proliferative capacity declines with age and is also different according to the localization of the cells: it is more intense with those originating from the central area then in those from the peripheral area of the cornea. The age-related decline of the proliferative capacity is not due to the shortening of the telomers, but to the stress-induced accelerated senescence of the cells.

Clinicopathologic findings in iridocorneal endothelial syndrome and posterior polymorphous membranous dystrophy after Descemet stripping automated endothelial keratoplasty.

PURPOSE: To report the histopathologic findings of the iridocorneal endothelial (ICE) syndrome and posterior polymorphous membranous dystrophy (PPMD) in 3 patients who underwent Descemet stripping automated endothelial keratoplasty (DSAEK), and to correlate these findings with the clinical diagnosis. METHODS: Three patients with clinical findings compatible with either ICE syndrome (1 patient) or PPMD (2 patients) underwent DSAEK. The DSAEK specimens were processed for light microscopy, immunhistochemical staining for cytokeratins AE1/3 and MAK6, and electron microscopy. RESULTS: Examination of the DSAEK specimens showed multilayered endothelial cells and thickened Descemet membrane in all cases. Immunohistochemical staining for cytokeratins was positive in the endothelium in all cases. Ultrastructural examination showed a thickened Descemet membrane and wide-spaced collagen in Descemet membrane in 1 case of PPMD but not in 2 cases of ICE syndrome, including 1 case that carried the clinical diagnosis of PPMD. In 2 cases, the histopathologic evaluation of the DSAEK specimen confirmed the clinical diagnosis; however, in 1 case the pathological diagnosis was ICE syndrome, while the clinical diagnosis was PPMD. CONCLUSIONS: ICE syndrome and PPMD can be diagnosed and differentiated from one another by histopathologic evaluation of corneal specimens obtained at the time of DSAEK. We recommend submitting the corneal tissue obtained during DSAEK for pathological examination when the etiology of corneal edema is unclear.

A singular case of congenital self-healing histiocytosis with skin, liver and atypical eye involvement.

PURPOSE: To describe a rare case of congenital self-healing Langerhans cell histiocytosis (CSHLCH) presenting with atypical eye involvement. DESIGN: Case report. METHODS: A female newborn presented with purpuric lesions over the trunk, limbs, and face. Liver ultrasonography revealed hypoechogenic lesions with blurred borders. Biomicroscopy showed right posterior synechiae with fibrinoid deposits on the lens. At 7 months she presented with right acute glaucoma. RESULTS: Biomicroscopy showed the presence of inflammatory pseudo-membrane covering the anterior surface of the lens, iris, and iridocorneal angle. Ab externo trabeculotomy was performed; access to the anterior chamber with capsulorrhexis forceps permitted a peeling of the pseudo-membrane with normalization of the intraocular pressure. Histologic examination of the membrane revealed an inflammatory tissue with CD1a and S-100 positive histiocytic cells. CONCLUSIONS: This is the first case of CSHLCH describing acute glaucoma secondary to a pseudo-inflammatory membrane with typical histiocytic cells, occluding the iridocorneal angle.

Ocular gene transfer of active TGF-beta induces changes in anterior segment morphology and elevated IOP in rats.

Purpose. Transforming growth factor beta (TGF-beta) is known to play a crucial role in wound healing and fibrotic tissue remodeling. A large body of evidence suggests a role for this cytokine in the pathogenesis of glaucoma; however, the mechanisms by which it affects anterior segment morphology are not well understood. Therefore, the purpose of this study was to examine the effects of TGF-beta overexpression on anterior segment morphology and subsequent effects on intraocular pressure. Methods. Adenoviral gene transfer was used to deliver active TGF-beta1 to the rat eye. Measurements of intraocular pressure were taken with a tonometer on days 0, 14, 21, and 29. Histologic analysis was undertaken to examine anterior segment morphology, and markers of matrix deposition and fibrosis were used. Results. Gene transfer of TGF-beta in the anterior segment resulted in the formation of peripheral anterior synechiae (PAS), which consisted of a fibroproliferative region of corneal endothelial cells, matrix accumulation, and decrease in trabecular meshwork expression of alpha-smooth muscle actin. These features were accompanied by ocular hypertension. Conclusions. Gene transfer of TGF-beta into the anterior segment induces aberrant PAS associated with the transition of corneal endothelial cells and subsequent matrix deposition. These features are highly reminiscent of human iridocorneal endothelial (ICE) syndrome. Gene transfer of TGF-beta can, therefore, be used to induce anatomic changes in the anterior segment in a rodent model that result in ocular hypertension.