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PubMed1986

Aniridic glaucoma: the results of gonio-surgery to prevent and treat this problem.

Repetitive gonioscopy of children with congenital aniridia confirms the presence of an angle abnormality which can be progressive and cause glaucoma. This abnormality features obstruction of the trabecular meshwork by variable mixtures of anterior migration of the peripheral iris and thickening of the uveal meshwork associated with a vascular net over exposed trabecular meshwork adjacent to the anterior edge of the iris. Preliminary results of prophylactic gonio-surgery in 28 eyes of 16 children with an average age of 4 years was reported. This surgery was performed without complication and produced a permanent exposure of the trabecular meshwork to the anterior chamber for an average of 8 circumferential hours, if two procedures were performed. Preliminary results suggest a stabilization of eye pressures at least through childhood and encourage the continuation of these prophylactic operations on selected eyes with congenital aniridia. Therapeutic goniotomy for established acquired glaucoma in congenital aniridia cannot be relied on, but may be a benefit for early detected cases or for glaucoma associated with aniridia in infancy.

Child↗
PubMed2000

Ultrasound biomicroscopy of the eye in cystinosis.

OBJECTIVE: To describe the ocular ultrasound biomicroscopy (UBM) findings in patients with cystinosis. METHODS: Six patients with infantile nephropathic cystinosis, aged 16 to 25 years, and 6 controls (matched for age and spherical refractive error) were examined clinically and with UBM. Scleral reflectivity, corneal and iris thickness, central anterior chamber depth, angle width, trabecular meshwork to ciliary process distance, and ciliary sulcus width were measured. RESULTS: No patient had glaucoma or posterior synechiae, but all had crystals in the trabecular meshwork apparent with gonioscopy. Using UBM, the cornea and iris appeared similar in both groups, but the scleral reflectivity was increased in patients (P =.003). The angle was narrower in patients (mean +/- SD, 20 degrees +/- 7 degrees ) than controls (31 degrees +/- 5 degrees, P<. 001). The anterior chamber was shallower in patients (2556 +/- 197 microm) than controls (2968 +/- 284 microm, P<.001). The ciliary sulcus was closed or narrow in all patients (83 +/- 112 microm) compared with controls (339 +/- 135 microm, P<.001), with a reduction in the trabecular meshwork to ciliary process distance. CONCLUSIONS: This report of ocular UBM findings in cystinosis demonstrated narrowing of the angle and a ciliary body configuration similar to that reported for plateau iris syndrome. Gonioscopy demonstrated crystals in the trabecular meshwork. These findings may explain the predisposition of these patients to glaucoma.

Adolescent↗
PubMed1989

Proteins secreted by human trabecular cells. Glucocorticoid and other effects.

The capacity of cultured human trabecular meshwork (HTM) cells to secrete an extracellular matrix was studied by indirect immunofluorescence. Synthesis of nine extracellular matrix (ECM) proteins known to be present in the normal trabecular meshwork was assessed in three HTM cell lines. Fourteen primary antibodies were used and cultures were labeled two and four weeks after confluence. The HTM cell lines showed consistent labelling patterns for the normal extracellular connective tissue constituents including collagens (types I, III, IV, V and VI), glycoproteins (laminin and fibronectin) and a basement membrane-associated proteoglycan. These antigens were localized to the basal cell surface in an extracellular reticular pattern corresponding to cell margins. Dextran addition at confluence helped to intensify the staining of these components, but ascorbate had no apparent effect. Interestingly, elastin, another normal component of the trabecular meshwork, was not identified under standard conditions, or after addition of ascorbate or dextran. However, elastin could be detected intracellularly following dexamethasone treatment for three days, and extracellularly in punctate deposits when this treatment was used for 1 or 2 weeks. Our findings indicate that HTM cells may be responsible for the secretion and maintenance of all the major ECM constituents of the trabecular meshwork. The elastin results suggest a possible mechanism contributing to obstruction of outflow in steroid glaucoma if increased amounts of elastin are also produced in vivo. This approach can also serve as a useful baseline for comparison with HTM cell lines treated with glaucoma medications or obtained from patients with glaucoma.

Antibodies↗
PubMed1992

[Ultrastructural observations of the anterior chamber angle tissues in congenital glaucoma].

18 trabeculectomy specimens of congenital glaucoma were examined by light and transmission electron microscopy with the finding that the primary anomalies in congenital glaucoma included the developmental defect of trabecular meshwork, excessive collagen fibrils in the trabecular matrix, shifting forward of ciliary muscle fibers, and persistent mesenchymal tissue in the chamber angle. The authors also pointed out the importance of the secondary lesions of the trabecular meshwork in the pathogenesis of congenital glaucoma.

Anterior Chamber↗
PubMed1983

Influence of the number of laser burns administered on the early results of argon laser trabeculoplasty.

We conducted a prospective, randomized, double-masked study to examine the influence of the number of burns administered on intraocular pressure after argon laser trabeculoplasty. Each of 40 patients with open-angle glaucoma had 50 burns placed over one half the trabecular meshwork (Group 1, 20 patients) or 100 burns placed over the entire trabecular meshwork (Group 2, 20 patients). There was no significant difference between the mean intraocular pressure decreases in Group 1 (-9.20 +/- 6.43 mm Hg) and Group 2 (-6.95 +/- 5.74 mm Hg) after two months (P less than .25). In each group, the intraocular pressure was lowest after two months in those patients in whom it was not increased during the immediate postoperative period (Group 1, P less than .006; Group 2, P less than .07). Because the changes in intraocular pressure were statistically similar in the two groups and because patients receiving only 50 burns may have fewer complications, administering 50 laser burns to one half the trabecular meshwork appears to be the better choice for an initial procedure.

Double-Blind Method↗
PubMed1992

Distinctive distribution of HLA class II presenting and bone marrow derived cells in the anterior segment of human eyes.

Cells of bone marrow origin that normally occupy the stroma of the murine iris and ciliary body have been implicated in the immune phenomenon, anterior chamber associated immune deviation (ACAID). Following injection of antigen into the anterior chamber, cells of this type deliver an ACAID inducing signal into the systemic circulation, presumably through the outflow tract. In an effort to identify such cells in man, anterior chambers of 34 human donor eyes of different age groups were stained immunocytochemically with monoclonal antibodies directed at HLA class II molecules, CD 45 (a molecular marker of bone marrow-derived cells) and macrophage-associated membrane molecules (CD 68, CD 14). Within the outflow tissue, the cells of the filtering trabecular meshwork stained with none of those reagents. However, infrequent single, dispersed, dendritic cells were positively stained in the intertrabecular spaces. More numerous labelled cells were found in the anterior- and posterior-most portions of the non-filtering part of the trabecular meshwork. These cells were continuous with stained cells adjacent to the outer wall of Schlemm's canal and to the collector channels. Numerous labelled cells were seen in the vicinity of the intra- and episcleral vessels, the ciliary meshwork, the stroma of the ciliary muscle and epithelial processes, and the iris stroma. With advancing age, increasing numbers of CD 45+, HLA class II expressing cells appeared to accumulate in the so-called uveoscleral pathway. These results indicate that bone marrow-derived cells with the potential to function of ACAID induction reside within human eyes, and that cells of this type are located not only in the stroma of iris and ciliary body, but within the non-filtering portions of the trabecular meshwork and the uveoscleral pathway. The appearance of rare CD 45+ cells "in transit" in the filtering trabecular meshwork is compatible with the view that cells carrying ACAID-inducing signals to the systemic immune apparatus escape from the eye by this route.

Adult↗
PubMed1994

Ultrastructural observations of the anterior chamber angle tissues in congenital glaucoma.

Eighteen trabeculectomy specimens of congenital glaucoma were examined by light and transmission electron microscopy. The results showed that the primary anomalies in congenital glaucoma included the developmental defects of trabecular meshwork, excessive collagen fibrils in the trabecular matrix, shifting forward of ciliary muscle fibres and persistent mesenchymal tissues in the anterior-chamber angle. The authors also pointed out the importance of the secondary lesions of the trabecular meshwork in the pathogenesis of congenital glaucoma.

Anterior Chamber↗
PubMed1986

Unconventional aqueous humor outflow of microspheres perfused into the equine eye.

Normal drainage of aqueous humor from the anterior chamber of the equine eye occurred through conventional and unconventional routes. To determine the degree of uveoscleral outflow in the pony, 1- and 3-microns (diam) microspheres were perfused through the anterior chamber for 60 and 90 minutes. Two eyes were treated with pilocarpine before perfusion of spheres to observe any effect on outflow. Presence of spheres was detected by scanning electron microscopy and verified by light microscopy. By 60 minutes of the perfusion, 1- and 3-microns spheres thoroughly infiltrated the anterior uveal trabecular meshwork. The 3-microns spheres were notably excluded from the corneoscleral trabecular meshwork, whereas the 1-micron spheres packed into the corneoscleral trabecular meshwork and mixed with the angular aqueous plexus and intrascleral plexus vessels. After 90 minutes, 1- and 3-microns spheres penetrated the prominent supraciliary space and mixed with the suprachoroidea of the midchoroid. The 1-micron spheres infiltrated tissues more extensively than did the 3-microns spheres, packing into the anterior meshwork and supraciliary space and also moving as far posterior as the suprachoroidea of the peripapillary retina. Spheres also entered the iris, mostly at the root. Several 3-microns spheres moved into the interstitial spaces around axon bundles and vessels in the iris. The 1-micron spheres packed into these spaces in the iris root and were observed in the lumens of iris vessels. Single 1-micron spheres were observed in the lumens of choroidal vessels posteriorly. The present study supported evidence for uveoscleral and uveovortex flow in the horse and indicated that it may be more extensive than that in other species investigated (ie, the dog).

Animals↗
PubMedDate not supplied

Trabecular damage due to blunt anterior segment injury and its relationship to traumatic glaucoma.

Gonioscopy, performed within 48 hours of traumatic hyphema, revealed not only angle recession but also a high incidence of damage to the trabecular meshwork and the Schlemm canal. These trabecular lesions tend to scar and become much more difficult to recognize over the ensuing weeks. Large tears into the ciliary body (angle recession) also had a tendency to "close." Using a specially calibrated BB gun hyphema was induced in rhesus monkeys. Trabecular tears were recognized by gonioscopic and histologic examination. Impaired outflow facility developed between 10 and 30 days after injury in the one surviving animal studied to date. In patients developing open-angle glaucoma years after trauma, evidence of past trabecular injury was seen by gonioscopy in addition to the obvious ciliary body tears (angle recession). The "normal" fellow eye had early glaucoma, ocular hypertension, or "high normal" intraocular pressure. The evidence presented supports the hypothesis that traumatic glaucoma is the result of trabecular meshwork injury from the original trauma and the rapid scarring that results, in combination with an underlying predisposition for the development of primary open-angle glaucoma and the passage of time.

Adolescent↗
PubMed1985

Long-term effects of Q-switched ruby laser on monkey anterior chamber angle.

In an attempt to clarify whether pulsed lasers might be able to cause permanent fistulas from the anterior chamber to the interior of the canal of Schlemm, slightly suprathreshold, low energy, small diameter Q-switched ruby laser pulses were applied to the trabecular meshwork of nine eyes of six rhesus monkeys. Clinical examinations during the next 2 months disclosed no adverse effect on the cornea, iris, lens, or retina. There was transient mild inflammation in five eyes. Intraocular pressure was not changed significantly; the facility determined by perfusion of the anterior chambers at 2 months was normal. Light microscopy and scanning electron microscopy show localized trabecular lesions; some are slightly indented, but there is no persistent penetration to Schlemm's canal. Endothelial cells, confluent with those of the cornea, cover the inner (anterior chamber) surface of the lesions. Cross-sections through the center of a lesion show that trabecular meshwork and Schlemm's canal have been obliterated by the treatment and healing; these changes are similar to those previously seen after argon laser monkey trabecular treatment. In the untreated areas, between pulsed laser application sites, trabecular meshwork and Schlemm's canal are normal by light microscopic and scanning electron microscopic examination. Any effect on IOP from this particular type of pulsed laser treatment of the trabecular meshwork is probably not due to trabeculopuncture and flow of fluid through the fistula.

Animals↗
PubMed1996

Transforming growth factor-beta 1 and -beta 2 positively regulate TGF-beta 1 mRNA expression in trabecular cells.

PURPOSE: To determine whether transforming growth factor (TGF)-beta 1 and -beta 2 and basic fibroblast growth factor (bFGF) induce the gene expression of TGF-beta 1 in the first-passage trabecular meshwork cells of the eye. METHODS: Trabecular meshwork cells were cultured from fresh porcine eyes and treated with 1 ng/ml of TGF-beta 1, TGF-beta 2, or bFGF for 1 hour. Cells maintained in serum-free medium were used as controls. Total cellular RNA was extracted, and the first-strand cDNA was synthesized. Multiplex polymerase chain reaction (PCR) and competitive PCR were performed on aliquots of the cDNAs by using either endogenous (glyceraldehyde-3-phosphate dehydrogenase [G3PDH]) or exogenous sequence (PCR mimic for TGF-beta 1) as internal standards, respectively. The obtained products were quantitated by laser densitometry, and statistical analysis was performed. RESULTS: The findings show that trabecular cells in vitro express the TGF-beta 1 messenger RNA constitutively. Both the techniques of multiplex PCR and competitive PCR demonstrated that the addition of either TGF-beta 1 or TGF-beta 2 at a concentration present in normal aqueous humor increased the mRNA levels of TGF-beta 1 by 2.82-to 3.07-fold over the controls, and these results were statistically significant (P < 0.01). Basic fibroblast growth factor did not have an effect on TGF-beta 1 expression (P < 0.05). CONCLUSIONS: Transforming growth factor-beta 1 activates its own gene expression in trabecular cells. Considering the multifunctional property of this cytokine, which includes increased deposition of extracellular matrix material and growth inhibition of trabecular cells, a change in its concentration within the eye would have a profound effect because of this autoinductive activity. Transforming growth factor-beta 2 treatment of trabecular cells also increased their expression of the TGF-beta 1 gene. The authors previously showed that the level of TGF-beta 2 in the aqueous humor of glaucomatous eyes is significantly higher than that of age-matched nonglaucomatous controls. The current finding suggests that this growth modulator may exert its effects directly on the trabecular cells or that it may act indirectly through upregulating the production of TGF-beta 1.

Animals↗
PubMed1993

Trabecular cells of the eye express messenger RNA for transforming growth factor-beta 1 and secrete this cytokine.

PURPOSE: To determine whether trabecular tissue in vivo and cultured trabecular cells have the messenger RNA transcript for transforming growth factor-beta 1 (TGF-beta 1), and to examine whether these cells synthesize and secrete TGF-beta 1 in vitro. METHODS: Total RNA was isolated from the trabecular meshwork, iris, and ciliary body freshly excised from porcine eyes as well as from cultured trabecular cells, and the reverse transcriptase-polymerase chain reaction and Southern hybridization were used for detection of TGF-beta 1 messenger RNA. The amount of TGF-beta 1 secreted by trabecular cells in culture was determined by radioimmunoassay. RESULTS: Excised whole trabecular tissue, iris, and ciliary body, as well as cultured trabecular cells expressed messenger RNA transcripts for TGF-beta 1. On the ethidium bromide-stained agarose gel, two PCR-amplified products (161 and 400 base pairs) were found in the total RNA isolated from cultured trabecular cells. The oligonucleotide probe specific for TGF-beta 1 detected only one band with the expected length of 161 base pairs. The secretion of TGF-beta 1 into conditioned medium was at the level of 16.7-20 pg/ml per 2 million trabecular cells during a 24-hr period. CONCLUSIONS: These investigations show that the trabecular meshwork, iris, and ciliary body in vivo express the messenger RNA transcript for TGF-beta 1, and that trabecular cells in vitro synthesize and secrete this cytokine. The TGF-beta 1 present in normal aqueous humor may be derived locally, at least in part, from the cells of the trabecular meshwork, iris, and ciliary body. Abnormal synthesis, secretion, activation, and clearance of TGF-beta 1 may contribute to the pathogenesis of many ocular disorders, including primary open-angle glaucoma.

Animals↗
PubMed1984

Effects of chronic intracameral injections of chondroitin sulfate on cat eyes.

The effect of chondroitin sulfate on the metabolism of trabecular meshwork was studied by repeatedly injecting a chondroitin sulfate solution into the anterior chamber of cat (experimental) eyes for 28-29 weeks. The aqueous humor of the opposite (control) eyes were similarly replaced with a phosphate-buffered saline-glucose solution. The intraocular pressure of the experimental eyes was increased 4-7 mm Hg above that of the control eyes for a prolonged period of time. In addition, collagen fibers, elastic fibers, and basement membrane-like material were moderately increased in the trabecular meshwork of experimental eyes. Three forms of thickened basement membranes of endothelial cells were observed. The compact multilaminated basement membrane was formed concentrically around some of the trabecular beams. The discontinuous, thin basement membrane was seen among bundles of coarse collagen in association with long spacing collagen fibers. Also, fine filaments were noted streaming from the plasma membrane and basement membrane of endothelial cells of angular aqueous veins. Chondroitinase ABC was able to remove ground substance in the elastic fiber of the trabecular meshwork. Biochemically, the chamber angle tissues from these eyes showed a higher synthetic activity of glycosaminoglycans and proteins. Chondroitin sulfate appears to have a direct effect on trabecular meshwork and can influence the physiologic function of these cells.

Animals↗
PubMed2005

Scleral indentation optimizes visualization of anterior chamber angle during goniosynechialysis.

PURPOSE: To propose a new surgical technique for optimized visualization of the chamber angle using scleral indentation under an operating microscope in goniosynechialysis (GSL). PATIENTS AND METHODS: Six volunteers with normal chamber angle and five patients with synechial angle closure glaucoma were examined. Scleral indentation 2 mm posterior to the limbus was performed during observation of chamber angle. Width of trabecular meshwork in images was recorded through a CCD camera mounted on an operating microscope. Trabecular-iris angle and trabecular-corneal angle obtained by ultrasound biomicroscopy were used for the parameters for the angle configuration. GSL with scleral indentation was performed in the patients. RESULTS: According to the visibility of the chamber angle, width of trabecular meshwork in images significantly increased from 0.34 +/- 0.08 mm equivalent (mean +/- SD) to 0.67 +/- 0.14 mm equivalent (P = 0.0001) with scleral indentation. According to the angle configurations, trabecular-iris angle significantly increased from 39.6 +/- 3.8 degrees to 47.5 +/- 6.6 degrees (P = 0.0016), and trabecular-corneal angle significantly decreased from 169.8 +/- 5.5 degrees to 158.7 +/- 5.4 degrees (P < 0.0001). All patients were successfully treated with GSL using scleral indentation. CONCLUSION: Scleral indentation provided the surgeon an optimized visualization of the anterior chamber angle. Deepening of the chamber angle and steeping in trabecular-corneal curvature probably induced the plane of the trabecular meshwork less oblique to the surgeon's visual axis. This enhanced visualization promises the accuracy and safety of GSL.

Aged↗
PubMed1994

Excimer laser photoablative filtration surgery: histology and ultrastructure in 4 human cadaver eyes.

The purpose of this study was to verify the feasibility of ab externo layer-by-layer excimer laser photoablative removal of limbal tissue down to the trabecular meshwork and to assess the damage caused by this procedure to the neighbouring structures. Excimer laser photoablation (193 nm) can remove layers of corneal tissue effectively with little or no damage to the adjacent areas. Previous experimental studies have demonstrated a decrease in outflow resistance after ab-externo photoablative removal of juxtacanalicular tissue. We have performed ab-externo photoablative removal of limbal tissue overlying the trabecular meshwork in four freshly enucleated eyes from our Eye Bank. The beam of an excimer laser (wavelength 193 nm; fluence 180 mJ/Sq.cm) was shaped using a metal mask with a rectangular opening of 1.2 x 2.5 mm. After removing the conjunctiva, photoablation was carried out at maximum surgical microscope magnification (40 x) until trabecular meshwork appeared at the bottom of the crater. Light microscopy showed that craters had smooth walls and their base reached the Schlemm's canal area; all structures appeared of normal morphology. Transmission electron microscopy showed a thin layer of amorphous material or pseudomembrane on the side walls of the crater; corneoscleral collagen fibers were abruptly interrupted and undistorted. At the bottom of the crater the trabecular meshwork and Schlemm's canal tissues appeared normal.

Aged↗
PubMed1999

Bradykinin decreases outflow facility in perfused anterior segments and induces shape changes in passaged BTM cells in vitro.

PURPOSE: To investigate the effects of bradykinin (BK) on the outflow facility (C) of human and bovine perfused anterior segments, the [Ca2+]i of cultured bovine trabecular meshwork (BTM) cells, and the area and major axis of BTM cells. METHODS: Cellular studies were performed using first- through third-passage cultures of BTM cells. For [Ca2+]i and shape change assessment, BTM cells were loaded with fura-2 acetoxymethyl ester, and individual fluorescence images were analyzed after the different experimental manipulations. C studies were performed in vitro using human and bovine anterior segments perfused at constant pressure. RESULTS: Bradykinin at 10(-6) M elicited a [Ca2+]i increase of 8 to 10 times the basal levels in 90% of the studied cells. From the responder cells, 60% elicited a 15%+/-1% reduction of the initial cell area, and 37% showed a 13%+/-2% reduction of their major axis. Bradykinin failed to induce any effect in the presence of the BK-B2 receptor antagonist HOE-140. Zero [Ca2+]o the depletion of intracellular stores with thapsigargin, or the presence of the calmodulin antagonist W13, decreased the BK response significantly (P < 0.001; P < 0.001; and P < 0.05). A second application of BK elicited a significantly lower (P < 0.001) response than the previous one. Perfusion with 10(-6) M BK decreased CD, calculated as the area under the curve, by 13%+/-4% (P < 0.05) in human anterior segments and 12%+/-4% (P < 0.05) in bovine anterior segments. The presence of 10(-6) M HOE-140, a BK-B2 receptor antagonist, completely blocked the decrease in C after perfusion with BK. CONCLUSIONS: The C of human and bovine trabecular meshwork (perfused anterior segments) is decreased by BK, acting through BK-B2 receptors. Primary cultured BTM cells respond to BK stimulation by increasing their [Ca2+]i by mobilization of extracellular and intracellular Ca2+. Moreover, these cells are reduced in area and their major axis shortened after the [Ca2+]i peak elicited by BK through BK-B2 receptors. The [Ca2+]i mobilization and shape changes are calmodulin dependent. Taking into account the [Ca2+]i mobilization, the BTM shape changes, the decrease of C, and the temporal sequence of these parameters, a contraction of trabecular meshwork cells related to the functional role of trabecular meshwork is discussed.

Aged↗
PubMed2005

Scanning electron microscope study of the rabbit anterior chamber angle.

The three-dimensional fine structure and the collagenous framework of the anterior chamber angle (chamber angle) of albino rabbits, which does not posses a Schlemm's canal, were examined, with or without NaOH maceration, by scanning electron microscopy. The chamber angle is ill defined because the deep ciliary cleft appears parceled by iris pillars. The collagenous framework of the pectinate ligaments and iris pillars arising from the iris root join to the collagen bundles of the trabecular sheet, and the surface of the ciliary cleft is covered by an endothelial cell layer that screens the trabecular meshwork. Round openings are apparent in the recesses of the ciliary cleft, with junctions between more superficial or deeper trabecular sheets resulting in direct communication between adjacent trabecular spaces. Openings of the angular aqueous plexus/sinus in place of Schlemm's canal were seen on the inner surface of the corneosclera after removing the trabecular meshwork. The framework of the trabecular sheet is basically formed of circumferentially arranged flat collagen bundles and reticularly diverged narrow collagen bundles extending from them. There is no shift between collagen bundles of the trabecular meshwork and the corneosclera, suggesting a frail connection between the two tissues.

Animals↗
PubMed2002

Proteoglycans in the eye.

PURPOSE: Various proteoglycans are expressed in ocular tissues. We investigated and reviewed the distribution and the potential roles of proteoglycans in cornea, trabecular meshwork, and retinal tissues. METHODS: Immunohistochemical studies were performed in rat ocular tissues. The concentration of transforming growth factor (TGF)-beta2, which regulates the expression of proteoglycans in aqueous humor from human glaucomatous eyes, was evaluated by enzyme-linked immunosorbent assay (ELISA). In retinal tissues, we examined the localization of 2 soluble nervous tissue-specific chondroitin sulfate proteoglycans, neurocan and phosphacan, by immunohistochemical analysis, then investigated the effect on the neurite outgrowth of cultivated retinal ganglion cells. RESULTS: The expression of chondroitin sulfate in stroma was upregulated at early postnatal stages and reduced during development in rat eyes. In trabecular meshwork tissues, immunohistochemical studies showed the intense expression of decorin. Moreover, elevated levels of TGF-beta2 in the aqueous humor from glaucomatous patients were observed. In retinal tissues, neurocan and phosphacan were expressed mainly in nerve fiber-rich layers during rat postnatal stages. In vitro, the neurite extension from retinal ganglion cells was inhibited by neurocan and phosphacan. CONCLUSIONS: Soluble extracellular proteoglycans in corneal and trabecular meshwork tissues contribute to the stromal transparency in the corneal tissues and the resistance of the aqueous humor outflow in trabecular meshwork tissues. In retinal tissues, chondroitin sulfate and heparan sulfate proteoglycans are not only secreted into the extracellular space of retinal tissues but also expressed in the membrane of the retinal cells, contributing to the neural network formation and the maintenance of the interphotoreceptor matrix.

Animals↗