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Case 2.. Trabeculectomy sample from the right eye. A: Light micrographs. B-D: Transmission electron microscopy. A: Some remains of trabecular meshwork (TM) and an anterior ciliary vessel (arrow) are observed. No Schlemm's canal or collector channels are visible. The ciliary muscle (CM) is inserted posterior to the trabecular meshwork (TM). Inset in A: Higher magnification of TM. B-D: In the area corresponding to the trabecular beams a compact tissue composed of abundant coalescent fibrillary collagen (C) and large amount of elastic-like fibers (e) is observed. The scarce endothelial cells lining the trabeculae show features of necrosis (arrowhead in C and D) and apoptosis (arrow in B). [SP: scleral spur].
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However, some rest of trabecular beams, as observed in the semithin section "Fig 4A", remained, allowing its analysis. No collector channels were detected "Fig 4A". The analysis of the ultrastructure revealed that in the region corresponding to the TM remains there was a compact tissue composed of abundant coalescent fibrillary collagen, large amount of elastic fibers and scarce endothelial cells which showed signs of necrosis and apoptosis "Fig 4B". It was difficult to identify the trabecular beams and no intertrabecular spaces were observed "Fig 4B and 4C". By contrast, in some areas the trabecular beams and the intertrabecular spaces were present "Fig 4D". Most endothelial cells lining these trabecular beams had disappeared, those remaining showing signs of necrosis and apoptosis "Fig 4D". The trabecular beams were filled by coalescent fibrillary collagen and abundant elastic-like fibers "Fig 4C and 4D". The ciliary muscle was inserted posterior to the TM "Fig 4A".
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Case 3.. Trabeculectomy sample from the left eye. A: Light micrograph. B-G: Transmission electron microscopy. A: Schlemm's canal (SC) has an open lumen. The corneoscleral trabecular meshwork (CTM) is constituted by quite compact trabecular beams. In the uveal trabecular meshwork (UTM) the intertrabecular spaces (b) are evident. B: The image shows a part of Schlemm's canal (SC) and the juxtacanalicular tissue. In the SC, only debris of necrotic endothelial cells (N) is visible on a thick basal membrane (bm). In the juxtacanalicular tissue, alternate layers of elastic tissue (e), necrotic cells (N), fibrillary collagen (C) and abundant ground substance (G) are seen. C: The corneoscleral trabecular meshwork is constituted by a quite disintegrated tissue. The trabecular beams (TB) (double arrows) have an "empty" appearance and are separated by intertrabecular spaces filled with debris of necrotic endothelial cells (N) and detached collagen (C) from the trabecular beams. D: The image shows fused trabecular beams (TB) (double arrows) and in some zones between them, debris from necrotic cells (white arrowhead) appears. The trabecular beams is constituted by a basal membrane (bm), many elastic-like fibers (e), fibrillary collagen (C), and abundant ground substance (G). E: The image shows two endothelial cells, one shows necrosis (N) and the other one has autophagic activity (arrow). F and G: Detail of the autophagic activity of an endothelial trabecular cell. F: Mitophagy (mp). G: Autophagosome (ap) with a double-membrane containing cytoplasmic material and organelles: mitochondria (M), rough endoplasmic reticulum (RER) and ribosomes (R).
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In semithin sections, we observed a SC with an open lumen, a quite compact CTM, and an UTM with well-developed intertrabecular spaces "Fig 5A". TEM revealed that most of the SC endothelial cells had disappeared with only debris of necrotic cells being observed "Fig 5B". The JCT was composed of alternating layers of abundant ground substance, elastic-like fibers, fibrillary collagen and necrotic stellate cells "Fig 5B". The CTM was difficult to recognize because the tissue was quite disorganized "Fig 5C". In some areas the trabecular beams were separate and the zones that would correspond with the inter-trabecular spaces were occupied by the remains of necrotic cells and by collagen that had been detached from the trabeculae "Fig 5C". In other areas the trabecular beams were fused, the boundary between them being recognized by the presence of necrotic cells debris "Fig 5D". The trabecular beam had basal membranes, many elastic-like fibers, fibrillary collagen and abundant ground substance "Fig 5D"; the latter gave to the trabecular beam an "empty" appearance "Fig 5C". The endothelial cells that delineate the trabecular beams were mostly necrotic "Fig 5E", and those remaining showed autophagic activity "Fig 5E-5G".
Case 3.. Trabeculectomy sample from the left eye. Transmission electron microscopy. A: Uveal trabecular meshwork. B: High magnification of inset in A. The endothelial cells of the trabecular beams have disappeared and the remains are necrotic (N). In some areas, the trabecular beams have an empty appearance (white arrow) while others are completely filled (arrowhead) with type VI non-fibrillary collagen (nf) intermingled with the collagen of the basal membrane (bm), as observed in B. The degraded type VI collagen detaches from the periphery of the trabecular beam (black arrow). [e: elastic-like tissue; G: ground substance].
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As occurs in the CTM, the UTM core had an "empty" appearance in some regions due to the presence of abundant ground substance "Fig 6A". IV) "Fig 6B". In some zones the whole trabecular beam was filled up by collagen VI "Fig 6B". The type VI collagen was degraded in the periphery of the trabecula and broken away from it "Fig 6B". All endothelial cells lining the trabecular beams had disappeared due to cell death by necrosis "Fig 6".
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Case 4.. Trabeculectomy sample from the left eye. Light micrographs. A: Schlemm's canal (SC), juxtacanalicular tissue (JCT) (double arrows), corneoscleral trabecular meshwork (CTM) (double arrows) and uveoscleral trabecular meshwork (UTM) (double arrows) are shown. Intertrabecular spaces are evident in both the CTM (a) and UTM (b). The ciliary muscle (CM) is inserted overlapping the SC. Numerous red blood cells can be observed in all aqueous outflow pathways (arrowhead). B: High magnification of the image shown in A. The SC shows a large lumen. A well-defined light-blue band (arrow) is visible in the JCT (double arrows) next to the endothelial cells lining the inner wall of the SC. The CTM has evident intertrabecular spaces in some areas (a) while in others, the trabecular beams are fused (white double arrow).
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In semithin sections obtained from the trabeculectomy of the OS, we observed a SC with a wide open lumen and a well-developed TM with abundant intertrabecular spaces "Fig 7". No collector channels were observed "Fig 7A". The ciliary muscle was abnormally inserted, overlapping the SC "Fig 7A".
Case 4.. Trabeculectomy sample from the left eye. Transmission electron microscopy. A and B: Schlemm's canal (SC), juxtacanalicular tissue (JCT) (double arrows), and corneoscleral trabecular meshwork (CTM) (double arrows). Some endothelial cells lining the inner wall of SC are necrotic (inset in A) and others have some vacuoles (inset in B). The JCT has two differentiated areas: a band (double white arrow) formed mainly by coalescent fibrillary collagen (C) with scarce "optically empty spaces" (o). Next to this band the second area is composed of fibrillary collagen (C), abundant elastic-like fibers (e), stellate cells (some of them necrotic) (S), and "optically empty spaces" (o). Most endothelial trabecular cells are necrotic (N). C: High magnification of the corneoscleral trabecular meshwork beams. The trabecular core is filled with coalescent fibrillary collagen (C), elastic-like fibers (e) and few "optically empty spaces" (o). The trabecular beams are lined by necrotic endothelial cells (N) lying on a basal membrane (bm) which is thickened in some areas. [a: intertrabecular spaces in CTM].
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Some of the endothelial cells lining the inner wall of the SC were necrotic "Fig 8A inset" and in those remaining, few vacuoles were observed "Fig 8B inset". The JCT had two clearly differentiated areas "Fig 8A and 8B". The first one consisted of a thick band of fibrillary collagen densely packed "Fig 8B" located next to the endothelial cells of the inner wall of the SC. In this band, no JCT stellate cells were observed and the elastic-like fibers were difficult to find "Fig 8B". In some zones, "optically empty spaces" "Fig 8A and 8B" were observed whereas in others the collagen fibers were so coalescent that those spaces could not be discerned "Fig 8A and 8B". Underneath this band of collagen, a second area formed by stellate cells (some of them necrotic), abundant elastic-like fibers, fibrillary collagen and "optically empty spaces" was observed "Fig 8A". In the CTM some of the trabecular beams were fused due to the disappearance of endothelial cells "Fig 8B and 8C" while others, showed large intertrabecular spaces "Fig 8A". Most of the CTM trabecular endothelial cells were necrotic "Fig 8B and 8C". Besides, scarce "optically empty spaces", elastic-like fibers and basal membranes (thickened in some areas), were visible "Fig 8C".
Case 4.. Trabeculectomy sample from the left eye. A: Light micrographs. B-D: Transmission electron microscopy. A: Uveal trabecular meshwork. The intertrabecular spaces are open (b). Most of the trabecular endothelial cells have disappeared and those remaining are necrotic (N). Numerous red blood cells appear between the trabecular beams (arrowhead). B-D: High magnification of an uveal trabecular meshwork trabecular beam. B: Cross section. C and D: Longitudinal section. The trabecular core is filled with successive layers of collagen fibers (C) giving the appearance of onion-like layers. The collagen of the basal membrane (bm) is interspersed between successive layers of fibrillary collagen (C). In B-D necrotic remains of the endothelial cells lining the trabecular beams are observed (N). [e: elastic-like fibers; nf: non-fibrillary collagen VI].
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The UTM had large intertrabecular spaces "Fig 9A". The core of the UTM beams was filled up by coalescent fibrillary collagen, basal membrane collagen and elastic-like fibers "Fig 9B-9D". The collagen was arranged in onion-like layers "Fig 9B-9D". Apparently, all the UTM endothelial trabecular cells were necrotic "Fig 9".
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Case 5.. Trabeculectomy sample from the right eye. Light micrographs. A: Schlemm's canal (SC) with an open lumen is present. The ciliary muscle (CM) is inserted posterior to the SC. B: The SC and two collector channels (CC) are observed. The intertrabecular spaces of the corneoscleral (a) trabecular meshwork (CTM) (double arrows) are less evident than those of the uveal (b) trabecular meshwork (UTM) (double arrows). C: Endothelial cells lining the SC wall (arrowhead). The arrow points to a giant vacuole. The juxtacanalicular tissue (JCT) (double arrows) is thick and composed of stellate cells (S), collagen fibers (C), and "optically empty spaces" (o). The CTM has a compact appearance although intertrabecular spaces (a) are visible. [E: trabecular endothelial cell].
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A developed SC "Figs 10, 11A and 11B" and collector channels "Fig 10B" with open lumens were observed. The endothelial cells covering de inner wall of the SC showed some giant vacuoles and abundant caveolae "Figs 10C and 11A". The JCT was thick, due to the presence of abundant and disorganized fibrillary collagen and abundant stellate cells (resembling fibroblast) and elastic-like fibers "Figs 10 and 11". "Optically empty spaces" were observed between the fibrillary collagen "Figs 10C, 11B and 11C". Although these trabeculae were quite compact, small intertrabecular spaces between them were visible "Figs 10B, 10C and 12A". The UTM were more separate between them than the corneal ones "Figs 10A, 10B and 13A". The ciliary muscle was inserted posterior to the TM "Fig 10A and 10B".
Case 5.. Trabeculectomy sample from the right eye. Transmission electron microscopy. A: Schlemm's canal (SC). The endothelial cells lining the inner wall of SC have some giant vacuoles (arrow) and numerous caveolae (arrowhead). B: Juxtacanalicular tissue (JCT). The thick JCT is constituted by disorganized fibrillary collagen (C), abundant stellate cells (S), elastic-like fibers (e) and "optically empty spaces" (o). C: High magnification of the JCT shown in B.
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A developed SC "Figs 10, 11A and 11B" and collector channels "Fig 10B" with open lumens were observed. The endothelial cells covering de inner wall of the SC showed some giant vacuoles and abundant caveolae "Figs 10C and 11A". The JCT was thick, due to the presence of abundant and disorganized fibrillary collagen and abundant stellate cells (resembling fibroblast) and elastic-like fibers "Figs 10 and 11". "Optically empty spaces" were observed between the fibrillary collagen "Figs 10C, 11B and 11C". All these findings result in a JCT with a compact appearance "Fig 11B and 11C".
Case 5.. Trabeculectomy sample from the right eye. Transmission electron microscopy. A: corneoscleral trabecular meshwork (CTM). This region is made up of several layers of trabecular beams (TB) (double arrows) separated by small intertrabecular spaces (a). Numerous flat endothelial cells (E) line the TB. B: High magnification of a trabecular endothelial cell (E). Pinocytosis vesicles (arrowhead), dense bodies (d), and phagocytized melanin granules (M) are visible within endothelial cells. Rough endoplasmic reticulum (RER). C: High magnification of a trabecular beam of the corneoscleral trabecular meshwork. The trabecular beams are filled by abundant disorganized fibrillary collagen (C), elastic-like fibers (e) and electron-lucent ground substance (G). The basal membrane (bm) of the trabeculae endothelial cells is observed. Pinocytosis vesicles (arrowhead).
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Although these trabeculae were quite compact, small intertrabecular spaces between them were visible "Figs 10B, 10C and 12A". The trabecular beams were lined by endothelial cells which were separated from the core of the trabecula by a basal membrane "Fig 12C". These cells showed numerous pinocytosis vesicles and dense bodies indicating a considerable phagocytic activity "Fig 12B and 12C". The core of the CTM trabecular beam possessed abundant disorganized fibrillary collagen that mostly filled the entire trabecula "Fig 12C". In addition, a few "optically empty spaces" containing an electron-lucent ground substance were observed "Fig 12C".
Case 5.. Trabeculectomy sample from the right eye. A: Light micrograph. B and C: Transmission electron microscopy. A: The uveal trabecular meshwork is well differentiated. The intertrabecular spaces are open (b). Well-preserved endothelial cells (E) alternate with necrotic cells (N). B: Two uveal trabecular beams lined with well-preserved endothelial cells (E) and one necrotic cell (N). The trabecular beams are filled with abundant fibrillary collagen (C) and elastic-like fibers (e). C: High magnification of an uveal trabecular beam containing a large amount of disorganized coalescent fibrillary collagen. Cross-sectioned collagen fibers (TC) alternate with fibers sectioned longitudinally (LC). Scarce electron-lucent ground substance (G) between collagen fibers and elastic-like fibers (e) is visible. Debris of endothelial necrotic cells (N).
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The UTM were more separate between them than the corneal ones "Figs 10A, 10B and 13A". Many necrotic endothelial cells appeared "Fig 13A and 13B" together with a large amount of disorganized fibrillary collagen filling the trabecular core "Fig 13B and 13C". Electron-lucent ground substance and elastic-like fibers were also found "Fig 13B and 13C".