Bilateral corneal perforation in familial amyloidotic polyneuropathy

Purpose: We report the progression of bilateral central perforating ulceration in the cornea of a patient with familial amyloidotic polyneuropathy (FAP), also known as hereditary Portuguese amyloidosis, who received two corneal grafts in an interval of 6 years. The pathology of the original host and the grafted cornea is described. Methods: Overall histology and immunolocalization of transthyretin, amyloid beta (Aβ), and epithelial and inflammatory markers were performed. Results: Corneal sensitivity and tear film were reduced. The grafted but not the original tissue contained amyloid deposits with transthyretin immunoreactivity. Epithelial and stromal thinning was accentuated in the graft, with epithelial dysplasia, hyperproliferation, and parakeratosis. Abundance of basement membrane material in hyperproliferative regions suggested recurrent attempts of wound healing. Activated keratocytes, ingrowth of vessels, infiltrated inflammatory, and immune cells reflect both acute and chronic inflammation. Conclusion: Amyloid deposits may progressively reduce corneal sensitivity and damage epithelium and stroma. Corneal neuropathy, together with impaired tear film, may entail the pathology of dry eyes as a bystander effect, contributing to exacerbation of epithelial injury, deregulated proliferation, and parakeratosis. Once established, both acute and chronic inflammation may sustain progression of the corneal patholog

In vivo confocal microscopy in hydroxychloroquine-induced keratopathy

Background: Vortex keratopathy, arising as a side effect of several medications, is characterized by golden-brown deposits in the cornea. Methods: A 41-year-old woman treated for sarcoidosis with hydroxychloroquine therapy and suffering from vortex keratopathy was examined by in vivo confocal microscopy. Scans of both corneas were performed. Results: By slit lamp examination, the left but not the right eye showed a golden-brown deposit throughout the cornea. In vivo confocal microscopy revealed the presence of highly reflective, dot-like intracellular inclusions concentrated in the basal epithelial layer. They were also detected within the anterior and posterior stroma, but not within the endothelium. In regions of the anterior stroma, devoid of inclusions, hyperreflective ramified keratocytes were observed, forming an extended interconnecting network. Conclusion: In addition to the granular deposits, in vivo confocal microscopy revealed hyperreflective, possibly phagocytic keratocyte

Ultrastructural alterations in capillaries of the diabetic hypertensive rat retina: protective effects of ACE inhibition

Aims/hypothesis: The ACE inhibitor cilazapril was administered to diabetic hypertensive rats to evaluate its ability to influence the development of retinal capillary alterations. Methods: Normotensive (strain: Wistar Kyoto) and genetically hypertensive (strain: spontaneously hypertensive) rats were rendered diabetic by intravenous injections of streptozotocin. Half of the diabetic animals received cilazapril with their daily food. At 20 weeks of diabetes, endothelial cells, pericytes and extracellular matrix were assessed by ultrastructural morphometry. Each experimental group consisted of seven animals. Results: Cilazapril normalised systolic arterial pressure in diabetic hypertensive rats (137±2mmHg compared with 188±16mmHg in non-medicated diabetic hypertensive rats, p<0.001). The number of endothelial intercellular junctions was reduced in untreated diabetic hypertensive rats (0.15±0.05, p<0.02, vs 0.47±0.20 in non-diabetic normotensive rats). In diabetic hypertensive animals treated with cilazapril, this loss was attenuated (0.32±0.16, p<0.05). The significant thickening of the basement membrane observed in the diabetic normotensive (132.8±19.4nm) and diabetic hypertensive (150.3±20.2nm) groups was decreased by cilazapril in the diabetic hypertensive group (116.7±11.0nm, p<0.01), but was unaffected in the normotensive (131.9±17.3nm) group. No protective effect of the drug was observed in either group on pericytes. Conclusions/interpretation: Long-term administration of an effective antihypertensive therapy normalises endothelial alterations and basement membrane thickness in diabetic hypertensive conditions, and thus may account for the well-known improvement of the blood-retinal barrier observed during antihypertensive treatmen

Remodeling of retinal capillaries in the diabetic hypertensive rat

PURPOSE. To document the effect of sustained systemic hypertension on the integrity and ultrastructural morphology of retinal capillaries in diabetic and nondiabetic rats. METHODS. Normotensive (strain Wistar-Kyoto; WKY) and genetically hypertensive (spontaneously hypertensive; SHR) rats were rendered diabetic by intravenous streptozotocin injection. At 20 weeks of diabetes, endothelial cells, pericytes, and extracellular matrix were evaluated by ultrastructural morphometry. Serum albumin was localized by immunofluorescence microscopy. RESULTS. The endothelial cell layer was markedly thinner in the diabetic normotensive animals. The number of intercellular junctions was reduced in both the nondiabetic and diabetic hypertensive group but less so in the diabetic normotensive group. No significant endothelial cell loss was noted in either of the experimental groups, whereas the number of pericytes and the number of their cytoplasmic processes were reduced in diabetic and hypertensive animals. Significant thickening of the basement membrane and increased permeability to serum albumin were observed in diabetic and hypertensive rats and were strongly enhanced in the combined diseases. CONCLUSIONS. Endothelial thinning and shape changes from an elaborate to a simpler form as well as rounding up of the pericytes and loosening of their vascular sheaths indicate remodeling of the vascular wall during chronic diabetes and sustained hypertension, before a characteristic vasculopathy becomes manifest. The combination of diabetes and hypertension enhances these features, as well as basement membrane thickening and breakdown of the blood-retinal barrier. (Invest Ophthalmol Vis Sci. 1999;40:2405-2410 E ssential hypertension, prevailing in persons with diabetes, 1,2 increases the risk of nephropathy 3,4 and morbidity and death of cardiovascular disease. 5 It is also one of the most important risk factors for diabetic retinopathy, influencing both its development and severity, 6 -8 and thereby plays a major role in visual loss in diabetic patients. -10 Because both hypertension and diabetes have an impact on the vascular wall, 11,12 they may act in an additive or synergistic manner. Indeed, thickening of the basement membrane, degeneration of pericytes, and rarefaction of vessels are features common to both diseases, whereas constriction of the capillaries in the hypertensive state or their dilation in the diabetic state are divergent traits. 22 This situation may lead to an increase in vascular wall shear stress and, eventually, to lasting endothelial damage. Moreover, in spontaneously hypertensive diabetic rats (SHR strain), the deposition of advanced glycation end products (AGEs) in arterioles and the occurrence of acellular retinal capillaries and microthromboses are strongly enhanced but can be corrected by aminoguanidine treatment that prevents the formation of AGEs. In this study, we documented the effect of diabetes on the structure of retinal capillaries in SHR and normotensive (Wistar-Kyoto; WKY) rats. The model of the SHR rat shares several features with essential hypertension in human

Comparative RNAi screening identifies a conserved core metazoan actinome by phenotype

RNAi Screens in Drosophila and human cells for novel actin regulators revealed conserved roles for proteins involved in nuclear actin export, RNA splicing, and ubiquitination

Oocyte shuttle, a recombinant protein transporting donor DNA into the Xenopus oocyte in situ

The newly developed oocyte shuttle protein contains a streptavidin moiety that tightly binds biotinylated DNA. Injected intravenously into adult Xenopus females, the protein-DNA complex is rapidly transported through the bloodstream and, within the ovary, the vitellogenin ligand present in the protein binds to the receptors at the surface of the oocytes. The bound complex is internalized and translocates into the oocyte nucleus thanks to an SV40 nuclear localization signal, enhanced by an adjacent casein kinase phosphorylation site. Functioning of the shuttle protein is documented by transporting DNA molecules that, upon intramolecular homologous recombination within the oocyte nucleus, express easily traceable markers such as green fluorescence or tetracycline resistance

Expression of αsmooth muscle actin in lens epithelia from human donors and cataract patients

In order to re-evaluate functional implications of αsmooth muscle actin (αSMA) expression in lens epithelial cells (LECs), we assessed its presence in donor lenses without visible opacities (DON), lenses with mature cataract (CAT), and cataractous lenses with posterior subcapsular opacities (PSO) or anterior subcapsular fibrosis (ASF). The levels of αSMA and transforming growth factor-beta2 (TGFβ2) mRNAs were measured by classical and real-time PCR. Expression and structural organisation of αSMA protein and β-catenin were monitored by Western blotting and confocal microscopy. All DON analysed contained measurable amounts of αSMA mRNA. In CAT without and with PSO, mRNA expression was increased and, again more than doubled in ASF. TGFβ2 mRNA expression varied widely between the individual samples but was slightly increased in ASF. No correlation existed between αSMA or TGFβ2 expression and the age of the donors in any of the lens categories. Confocal microscopy revealed that, in DON and CAT, αSMA was preferentially expressed in a simple granular pattern in single or small clusters of LECs within a normally shaped cobblestone epithelium. Locally, the granules were merged into short stretches at the cell margin. In CAT, a few abnormally shaped cells contained polygonal αSMA structures and short stress fibres. In CAT with PSO and ASF, polygons and stress fibre bundles predominated in spindle-shaped cells. Expression patterns of different complexity were often present in the same epithelium. Apical polygons and basal stress fibres were detected within the same cell and may reflect instability of the interface between epithelium and cortical fibres and changes in adhesion to the capsule, respectively. High levels of βcatenin mRNA and protein were present in all lens types. However, with increasing complexity of αSMA organisation, βcatenin staining disappeared from the cell margin and basal infoldings and was shifted towards the cytoplasm and nucleus. The presence of αSMA in DON, the absence of any correlation between mRNA level and age, and the modest increase in complexity of αSMA-containing structures in CAT argue against an inevitable link between αSMA expression and the development of age-related cataract. Low levels of αSMA expression may reflect repair of normal wear and tear. In pathologic situations such as PSO and ASF, persisting stimulation and additional incentives may induce increased αSMA expression and more elaborate patterning, eventually leading to completion of EMT