No abstract

Structural alterations of pericytes in microvessels are important features of diabetic retinopathy. Although capillary pericytes had been known not to have α-smooth muscle actin (αSMA), a recent study revealed that a specific fixation method enabled the visualization of αSMA along retinal capillaries. In this study, we applied snap-fixation in wild type and streptozotocin-induced diabetic mice to evaluate the differences in vascular smooth muscle cells of the retina and the choroid. Mice eyeballs were fixed in ice-cold methanol to prevent the depolymerization of filamentous actin. Snap-fixated retina showed αSMA expression in higher-order branches along the capillaries as well as the arterioles and venules, which were not detected by paraformaldehyde fixation. In contrast, most choriocapillaris, except those close to the arterioles, were not covered with αSMA-positive perivascular mural cells. Large choroidal vessels were covered with more αSMA-positive cells in the snap-fixated eyes. Diabetes induced less coverage of αSMA-positive perivascular mural cells overall, but they reached higher-order branches of the retinal capillaries, which was prominent in the aged mice. More αSMA-positive pericytes were observed in the choroid of diabetic mice, but the αSMA-positive expression reduced with aging. This study suggests the potential role of smooth muscle cells in the pathogenesis of age-related diabetic retinopathy and choroidopathy.

Although many studies demonstrated the differences of clinical features, natural course, and response to treatment between typical age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV), differential microRNAs (miRNAs) expression in the aqueous humor (AH) between them has not been reported yet. We investigated the roles of miRNAs in the AH of patients with typical AMD and PCV using next-generation sequencing (NGS) and quantitative PCR (qPCR). Target genes and predicted pathways of miRNAs were investigated via pathway enrichment analysis using the Kyoto Encyclopedia of Genes and Genomes database. A total of 161 miRNAs from eyes with typical AMD and 185 miRNAs from eyes with PCV were differentially expressed. 33 miRNAs were commonly upregulated, and 77 miRNAs were commonly downregulated in both typical AMD and PCV groups. Among them, hsa-miR-140-5p, hsa-miR-374c-3p, and hsa-miR-200a-5p were differentially expressed and were predicted to regulate proteoglycans in cancer, p53 signaling pathway, Hippo signaling pathway, and adherens junction. The differential expression profiles and target gene regulation networks of AH miRNAs may contribute to the development of different pathological phenotypes in typical AMD and PCV. The results of this study provide novel insights into the pathogenesis, associated prognostic biomarkers, and therapeutic targets in AMD and PCV.

Purpose: We report a case of primary small cell neuroendocrine carcinoma arising from the lacrimal sac. Case summary: A 54-year-old man presented with epiphora that had been present for 1 month. He underwent lacrimal syringe analysis of the lower punctum in the right eye, which demonstrated fluid regurgitation from the upper punctum. Computed tomography revealed a 3.0 × 3.4 × 3.0 cm mass with an ill-defined margin in the right lacrimal sac, which demonstrated invasion of the lacrimal duct and bony destruction of the inferior and medial orbital walls. Incisional biopsy and histologic examination showed that the tumor was composed of small round tumor cells. On the basis of histopathological and immunohistochemical evaluations, a diagnosis of small cell neuroendocrine carcinoma was made. The patient received chemotherapy.Conclusions: To the best of our knowledge, this is the first case of primary small cell neuroendocrine carcinoma arising from the lacrimal sac in Korea. Small cell neuroendocrine carcinoma in the lacrimal sac should be regarded as a differential diagnosis for patients with a nasolacrimal duct obstruction.