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PubMed1991

Biphasic model of the trabecular meshwork in the eye.

A biphasic continuum model for the flow of intraocular fluid, the aqueous humour, in the trabecular meshwork is proposed in the paper. The model considers the meshwork as a circular ring with uniform thickness of homogeneous, isotropic, viscoelastic material swollen with continuously percolating aqueous humour. The model further assumes the permeability of the meshwork as a function of dilation in its solid phase. The study considers steady and quasisteady states. Approximate solutions to the problem are obtained by Picard's type iterative procedure and computational results for the dimensionless solid displacement, permeability and pressure profiles are presented. It is concluded that intraocular pressure has a permeability-decreasing effect, whereas the elasticity of the meshwork shows a permeability-increasing effect. Thus, rising intraocular pressure develops a further rise in itself, whereas the elasticity tends to diminish the intraocular pressure through facilitating aqueous outflow.

Aqueous Humor↗
PubMed1991

Chemoattractants produced by ocular cells induce trabecular meshwork cell migration.

Media conditioned by bovine corneal endothelium and scleral fibroblasts were found to induce the migration of bovine trabecular meshwork cells. The migrational activity had both chemokinetic (stimulated random motion) and chemotactic (directional migration) components. That produced by corneal endothelial cells had a markedly more potent effect. The relevance of these in vitro studies is discussed. Biochemically stimulated migration and loss of meshwork cells may be involved in the pathogenesis of glaucoma.

Animals↗
PubMed2001

A comparison of different embedding media on the ultrastructure of the trabecular meshwork.

PURPOSE: To determine whether the preservation of the extracellular matrix and the ultrastructural appearance of the trabecular meshwork are affected by different histologic processing protocols and embedding media. Conventionally used epoxy resins such as Araldite require complete dehydration of tissue, while the acrylic resin LR White requires only partial dehydration, better preserves tissue antigens, and has been reported to preserve more of the extracellular matrix. METHODS: Seven human eyes ranging in age from 2 months to 78 years were dissected and tissue samples from each eye processed and embedded in both Araldite and LR White media. The ultrastructure of the trabecular cells and the extracellular matrix of the meshwork was compared between media. The preservation of the extracellular matrix in the juxtacanalicular region was determined by measuring the amount of material immediately underlying Schlemm(1)s canal. Immunoelectron microscopy was used to determine the composition of this material. RESULTS: Araldite provided better resolution of ultrastructural details than freshly polymerized LR White. After a period of ripening for several months, however, resolution of tissue details in LR White improved. No significant quantitative difference was found in the amount of extracellular matrix underlying Schlemm's canal when comparing the two media. Neither post-mortem time to fixation (up to 31 hr), donor age, nor immersion vs. perfusion fixation technique affected the amount of extracellular material present in the comparison of the two embedding media. Immunogold labeling of the extracellular material within the juxtacanalicular tissue revealed the presence of collagen IV, laminin, and fibronectin in the basement membrane region immediately underlying the inner wall, and also in scattered patches within the juxtacanalicular tissue. CONCLUSIONS: Despite the less rigorous processing required for LR White than epoxy embedding, neither the appearance nor amount of the extracellular material was affected by the different embedding protocols. Prolonged post-mortem time to fixation did not affect the appearance nor amount of extracellular matrix. Immunolabeling revealed that the extracellular matrix of the juxtacanalicular tissue contains components of basement membrane material.

Acrylic Resins↗
PubMed1994

Biochemical effects of viscoelastic materials on the glycosaminoglycans in the organ-cultured rabbit trabecular meshwork.

We studied the effects of viscoelastic materials on the glycosaminoglycan (GAG) profiles in the organ-cultured rabbit trabecular meshwork (TM). The cultured specimens were divided into 4 groups: (1) control group; (2) 1% sodium hyaluronate-(Na-HA)-treated group; (3) 3% chondroitin-6-sulfate (CD6S)-treated group, and (4) 1% methylcellulose (MC)-treated group. They were cultured for 2 weeks and subjected to sequential enzymatic degradation. In the 1% Na-HA-treated group, the proportion of hyaluronic acid was significantly increased compared with the control group. In the 3% CD6S-treated group, the proportion of chondroitin sulfate was significantly increased compared with the control group. In the 1% MC-treated group, the GAG profile did not differ from the control profile.

Animals↗
PubMed2000

Characterization of gene expression in human trabecular meshwork using single-pass sequencing of 1060 clones.

PURPOSE: To study the gene expression profile of the human trabecular meshwork (HTM). METHODS: A polymerase chain reaction (PCR)-amplified cDNA library was constructed using RNA from the TM of a 67-year-old normal, perfused human eye. A total of 1060 clones were randomly selected for sequencing of one end. These sequences were searched against nonredundant GenBank and dbEST databases for similarity comparison by using a FASTA file and the BLASTcl3 program. Relative expression patterns of those clones that matched other expressed sequence tags (ESTs) were determined using the National Center for Biotechnology Information (NCBI) Unique Human Gene Sequence Collection (UniGene) database. RESULTS: Of the 1060 clones analyzed, 519 (48.9%) had sequences identical with known genes, 125 (11.8%) matched ESTs, and 189 (17.8%) did not match any database sequences. Of the remaining clones, 31 (3%) corresponded to mitochondrial transcripts and 196 (18.5%) to repetitive and noninformative sequences. It is notable that some of the genes highly represented in this library are not ubiquitously expressed in other tissues, which suggests a potentially important role in the HTM. As evidence for the presence of true novel genes in the library, one of the clones was fully sequenced. This clone comprised a complete open reading frame of 966 nucleotides, and its deduced amino acid sequence corresponded to a protein 33% similar to the MAS-related G-protein-coupled receptor. CONCLUSIONS: The identification of the more highly expressed genes in HTM and the discovery of novel genes expressed in this tissue provides basic information for further research on the physiology of the TM and for the identification of glaucoma candidate genes.

Adult↗
PubMed1998

Activation of phospholipase C and guanylyl cyclase by endothelins in human trabecular meshwork cells.

PURPOSE: To characterize effects of endothelins on activities of phospholipase C (PLC) and nucleotide cyclases in human trabecular meshwork (TM) cells. METHODS: Cultured simian virus 40-transformed human TM (HTM-3) or non-transformed (HTM-16) cells were used. Changes in the PLC activity were determined by assaying the production of [3H] inositol phosphates. Accumulation of cyclic GMP or cyclic AMP in cell lysate was measured by radioimmunoassay. RESULTS: Endothelin-1 (ET-1; 1 microM) stimulated PLC in HTM-16 cells, but Sarafotoxin S6c (SRTX), an ET(B) receptor subtype-selective agonist (1 microM), did not. Similar results were obtained in HTM-3 cells: ET-1, but not ET-3 or SRTX, activated PLC in a dose-dependent manner, with a calculated EC50 of 646 pM. The peptide also stimulated the accumulation of cGMP in a concentration-dependent manner with an EC50 of 37.2 pM. ET-3 or SRTX was not effective except at much higher concentrations. Both the PLC and guanylyl cyclase stimulation induced by ET-1 (10 nM) were completely inhibited by pretreating the cells with BQ-123 (<10 microM), an ET(A) receptor selective antagonist, but not by BQ-788 (10 microM), an ET(B) receptor subtype-specific antagonist. Neither ET-1 nor ET-3 stimulated adenylyl cyclase activity in HTM-3 cells at concentration as high as 1 microM. CONCLUSION: ET-1 activates PLC and guanylyl cyclase in TM cells. Potency profiles of ET receptor agonists and antagonists suggest that the ET(A) receptor subtype is involved in both actions of ET-1. The effects of the ET peptides in TM cells are interesting and could be part of the mechanism of their IOP-lowering effect.

Cell Line, Transformed↗
PubMed2001

Glucocorticoid induction of the glaucoma gene MYOC in human and monkey trabecular meshwork cells and tissues.

PURPOSE: To examine the intracellular and extracellular expression of myocilin in the human and primate trabecular meshwork (TM) in the presence and absence of glucocorticoids. METHODS: Myocilin expression was examined in cultured human TM cells by Northern blot analysis and myocilin antibody-mediated immunoprecipitation. Myocilin expression was quantified using high-resolution two-dimensional polyacrylamide gel electrophoresis of radiolabeled proteins from human TM cells, TM tissue explants, and perfused human anterior segments cultured with and without dexamethasone (DEX) for 14 to 21 days, as well as TM tissue from pigtailed monkeys treated orally for 1 year with cortisone acetate. Immunofluorescence with anti-myocilin antibodies was used to localize cellular and extracellular expression of myocilin in cultured human TM cells. RESULTS: Glucocorticoid treatment caused a significant induction of myocilin mRNA, a tetrad of cell-associated proteins, and 8 to 20 secreted proteins (molecular mass [M(r)] 56 and 59 kDa and isoelectric point [pI] 5.2 and 5.3) in some, but not all the cultured human TM cells and explanted tissues. Western immunoblot analysis using anti-myocilin peptide antibodies identified these proteins as encoded by the MYOC gene. There was significant induction of the myocilin proteins in three perfusion-cultured human eyes, in which DEX-induced elevated intraocular pressure developed. Monkeys treated 1 year with cortisol acetate showed steroid glaucoma-like morphologic changes in the TM that correlated with the induction of myocilin in the TM. Immunofluorescence analysis of cultured TM cells localized myocilin intracellularly in discrete perinuclear and cytoplasmic vesicular deposits as well as extracellularly on the cell surface associated with the extracellular matrix. In several DEX-treated TM cell lines, there were significant levels of myocilin secreted into the media. Enzymatic deglycosylation of proteins in the TM media converted the higher molecular weight isoforms of myocilin (approximately 57 kDa) to the lower molecular weight isoforms ( approximately 55 kDa). CONCLUSIONS: Although the function of myocilin is unknown, induction of these TM proteins was found in eyes in which glucocorticoid-induced ocular hypertension developed. Therefore, myocilin may play an important pathogenic role in ocular hypertension in addition to its role in certain forms of POAG.

Aged↗
PubMed2005

Ascorbic acid enhances nitric oxide production in trabecular meshwork cells.

PURPOSE: This study investigated the role of ascorbic acid on the production of nitric oxide (NO) in the trabecular meshwork (TM) cells. METHODS: After primarily cultured human TM cells were exposed to 1, 10, and 100 microM of L-ascorbic acid (LAA), with or without co-administration of 1 mM sodium nitroprusside or 100 microM hydrogen peroxide for 48 hr, cellular survival and NO production were measured with MTT and Griess assay, respectively. RESULTS: LAA significantly potentiated NO production in a dose-dependent manner (p<0.05) without affecting cell viability. LAA increased cell viability after hydrogen peroxide-induced oxidative stress in a dose-dependent manner. LAA enhanced NO production in TM cells and showed a cytoprotective effect against hydrogen peroxide-induced oxidative stress. CONCLUSIONS: LAA might be involved in the regulation of trabecular outflow by enhancing NO production in TM cells.

Ascorbic Acid↗
PubMed2002

Effects of nitric oxide on proliferation and apoptosis of cultured bovine trabecular meshwork cells.

The effects of different doses of nitric oxide (NO) on the proliferation and apoptosis of the cultured bovine trabecular meshwork (TM) cells were studied. L-arginine and NG-nitro-L-arginine methyl (L-NAME) were incubated with TM cells for 48 h. In the control group, no medicine was given. In the experimental groups, concentrations of L-arginine and L-NAME were 1 x 10(-7) mol/L, 1 x 10(-6) mol/L, 1 x 10(-5) mol/L, 1 x 10(-4) mol/L, 1 x 10(-3) mol/L and 1 x 10(-2) mol/L, respectively. NO2- in supernate, the proliferation and apoptosis of TM cells and mRNA expression of bcl-2 and bax were measured by Griess reagent, terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL), MTT assay and in situ hybridization, respectively. The results showed that L-arginine with concentration > or = 1 x 10(-4) mol/L could induce apoptosis of the TM cells and inhibit the proliferation of TM cells through increasing the NO levels, down-regulating bcl-2 mRNA expression and up-regulating bax mRNA expression; L-NAME with concentration > or = 1 x 10(-5) mol/L could induce the proliferation of the TM cells through suppressing the production of NO. It was concluded that NO in high level could induce apoptosis of the TM cells and suppress the proliferation of the TM cells.

Animals↗
PubMed2001

Identification of Kir2.1 channel activity in cultured trabecular meshwork cells.

PURPOSE: To study the presence of inwardly rectifying K(+) (Kir) channels in cultured bovine (BTM) and human (HTM) trabecular meshwork cells. METHODS: Cultures of BTM and HTM cells were obtained by an extracellular matrix digestion technique. Whole-cell patch-clamp recordings of BTM cells were performed with the appropriate solutions to detect K(+) currents. Also, Western blot analysis of Kir2.1 protein expression was performed on both cultured BTM and HTM cells. RESULTS: A strong inwardly rectifying current at negative potentials to the equilibrium potential for K(+) (E(K+)) and highly selective for K(+) was detected in 60% of cultured BTM cells. The slope conductance of the inward rectification was more pronounced when the extracellular [K(+)] was increased and was proportional to [K(+)](0.45). The current was blocked by Ba(2+) and Cs(+) in a voltage- and concentration-dependent manner, with K(d) at 0 mV, of 74.7 microM and 45.6 mM, respectively. Current amplitude was reduced by increasing extracellular [Ca(2+)]. The current was insensitive to 10 microM glibenclamide and 10 nM tertiapin. The application of 100 microM 8-Br-cAMP reduced the current by 50%. Kir2.1 channel expression was detected in confluent monolayers of BTM and HTM cells by Western blot analysis. CONCLUSIONS: A population of cultured BTM cells expressed an inwardly rectifying K(+) current that illustrates the biophysical and pharmacologic characteristics of the detected Kir2.1 channel protein. Kir2.1 channels are also thought to be present in HTM cells. Kir2.1 channels could be related to TM physiology, because they are involved in contractile and cell volume regulatory responses, two mechanisms that modify TM permeability.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1996

Glycosaminoglycans of the human trabecular meshwork in primary open-angle glaucoma.

PURPOSE: Glycosaminoglycans (GAGs) contribute to the filtration barrier of aqueous outflow through the trabecular meshwork (TM). The purpose of this biochemical study was to identify the type and amount of GAGs in normal and in primary open-angle glaucoma (POAG) TM and adjacent anterior segment structures. METHODS: The GAGs of 21 masked individual normal and POAG human TMs, as well as iris, ciliary body, and anterior sclera, were isolated biochemically, identified by selective GAG-degrading enzymes, and quantitated by computer-enhanced densitometry. RESULTS: In 10 normal TMs (8 donors, 65 to 83 years of age), the GAG profile was: hyaluronic acid (0.77 +/- 0.26 ng/microgram dry-defatted weight +/- SEM); chondroitin 4(6-) sulfates and dermatan sulfate, collectively referred to as chondroitin sulfates (1.90 +/- 0.13 ng); keratan sulfates (0.33 +/- 0.06 ng); heparitin sulfates (2.02 +/- 0.52 ng); GAG enzyme-resistant material (0.02 +/- 0.01 ng); and total GAGs (5.05 +/- 0.70 ng). In 10 POAG TMs (6 donors, 67 to 88 years of age), the GAG profile was: hyaluronic acid (0.18 +/- 0.11 ng; P < 0.02, a 77% decrease; 6 of 10 TMs contained no detectable hyaluronic acid); chondroitin sulfates (2.39 +/- 0.31 ng); keratan sulfates (0.21 +/- 0.06 ng); heparitin sulfates (1.36 +/- 0.43 ng); GAG enzyme-resistant material (0.08 +/- 0.01 ng; P < 0.02); and total GAGs (4.09 +/- 0.33 ng; statistically insignificant). In the POAG iris, hyaluronic acid content was less (82% decrease, P < 0.02), and the chondroitin sulfates content was higher (72% increase, P < 0.02). Similarly, the POAG ciliary body and anterior sclera contained less hyaluronic acid and more chondroitin sulfates. The GAG profile of a "glaucoma suspect" donor specimen was similar to that of the POAG donor specimen. CONCLUSIONS: The data provide the first quantitative biochemical profiles of GAGs of individual normal and POAG TM, and we suggest that a depletion of hyaluronic acid and the accumulation of chondroitin sulfates may increase aqueous outflow resistance in the POAG TM:

Aged↗
PubMed2003

Cell membrane stretch modulates the high-conductance Ca2+-activated K+ channel in bovine trabecular meshwork cells.

PURPOSE: Anterior chamber structures are subjected to changes in intraocular pressure (IOP). Several studies have pointed out that trabecular meshwork (TM) cells are sensitive to mechanical stretch and that cell-signaling mechanisms are activated in response to elevated pressure. Because membrane stretch has been shown to be a modulator of several ionic conductances, this study was conducted to determine its effects on the high-conductance Ca(2+)-activated K(+) (BK(Ca)) channels present in TM cells. METHODS: Primary cultures of TM cells from bovine eyes were used. Patch-clamp recordings were performed in the cell-attached, inside-out, and whole-cell configurations. To stretch the cell membrane, both suction to the rear end of the patch pipette and hypotonic shock were used. Intracellular calcium concentration ([Ca(2+)](i)) was measured in TM cells loaded with fura-2, using an epifluorescence microscope coupled to a charge-coupled device (CCD) camera. RESULTS: Electrophysiological characterization of BK(Ca) channels was in agreement with previous studies. In cell-attached patches, the open probability of the BK(Ca) channel (i.e., the amount of time the channel is open) increased consistently when 14- to 45-mm Hg suctions were applied at a constant depolarized voltage. At a constant pressure (25 or 45 mm Hg), channel openings increased when depolarizing pulses were applied to the patch. Stretch activation of the BK(Ca) channel was not mediated by increases in [Ca(2+)](i), because it was present in inside-out patches maintained at a constant Ca(2+) concentration. Nevertheless, it cannot be ruled out that at low suction levels, a minimum Ca(2+) concentration is necessary for channel activation. Whole-cell currents carried by BK(Ca) channels increased when the isotonic solution in the bath was exchanged with a hypotonic solution and were selectively blocked by iberiotoxin. In our conditions, the hypotonic shock did not modify [Ca(2+)](i). CONCLUSIONS: The data show that in TM cells, open probability of the BK(Ca) channel is enhanced by membrane stretching as well as by membrane depolarization and [Ca(2+)](i). Changes in membrane tension induced by cell volume increase also activated whole-cell BK(Ca) currents. Homeostatic mechanisms in TM cells may involve BK(Ca) channel activation in response either to changes in cell volume or changes in IOP.

Animals↗
PubMedDate not supplied

Ultrastructural localization of collagen IV, fibronectin, and laminin in the trabecular meshwork of normal and glaucomatous eyes.

PURPOSE: To determine whether differences in the ultrastructural characteristics or composition of the basement membranes of the trabecular lamellae and Schlemm's canal exist in normal eyes and eyes with primary open-angle glaucoma (POAG). Basement membranes play key roles in the attachment of the overlying trabecular cells and Schlemm's canal cells. METHODS: Electron microscopy used in conjunction with immunogold labeling was used to examine the ultrastructure of the basement membranes in the trabecular meshwork and to determine the presence of collagen IV, laminin, and fibronectin in 6 normal eyes and 6 eyes with POAG. To determine which cells in the meshwork synthesized these molecules in situ hybridization was studied in an additional 8 normal eyes. RESULTS: No distinctive ultrastructural changes were found in the basement membranes of glaucomatous eyes, whether early or advanced disease, when compared with normal eyes. Label for all three proteins was present in the basement membranes of the trabecular lamellae, Schlemm's canal, and in scattered patches within the juxtacanalicular tissue. Laminin and fibronectin were most abundant in the periphery of the sheath material surrounding the elastic tendons in the juxtacanalicular tissue. In contrast to previously published light microscopic studies, no increase in fibronectin was found in glaucoma. Regions of the basement membrane of the canal underlying giant vacuoles were similar to regions without giant vacuoles in both appearance and labeling. In situ hybridization revealed that mRNA for all three proteins was present in most trabecular cells throughout the meshwork; no regional differences in cellular labeling within were observed. CONCLUSION: The ultrastructural characteristics and immunogold labeling of basement membranes were similar in normal and glaucomatous eyes; no additional structures were labeled in POAG eyes that were not also labeled in normal eyes. Label of the patches of amorphous fibrogranular material within the juxtacanalicular tissue suggests it is basement membrane in origin, while the sheath material which is known to accumulate in POAG was not heavily labeled and does not appear to be basement membrane in origin.

Aged↗
PubMed1977

[Role of the trabecular meshwork in chamber water exchange based on model experiments].

On the basis of our experiments with models, we suppose that the trabecular meshwork possesses a pump mechanism with a sucking and compressing effect, forming a basic hydrodynamic mechanism together with the humour aqueous production and the uveal and episcleral outflow. This mechanism is able - in spite of the changes of certain factors - to keep the aqueous outflow and the intraocular pressure at a standard level in normal physiologic circumstances. Finally, it is possible that this mechanism can be influenced by the neurohormonal system, or in other words, it may be the physical manifestation of the neurohormonal effects.

Aqueous Humor↗
PubMed2003

Nitric oxide mediates epinephrine-induced apoptotic cell death of trabecular meshwork cells in vitro.

To evaluate the effect of epinephrine on the cellular proliferation and production of nitric oxide (NO) in trabecular meshwork (TM) cells, cultured porcine TM cells were exposed to epinephrine at various concentrations, with and without its NO inhibitor, N(omega)-Nitro-L-arginine methyl ester (L-NAME). The proliferation of TM cells and the production of NO were quantified by rapid colorimetric assays. Acridine orange/Hoechest 33342 staining and flow cytometry were done to evaluate apoptosis. Epinephrine inhibited the proliferation of cultured TM cells and produced NO at significant levels in a dose-dependent manner. However, the antiproliferative effect of epinephrine was abolished by L-NAME. Fluorescent microscopy and flow cytometric analysis revealed that epinephrine induced apoptotic cell death, which was suppressed by L-NAME. The current results suggest that the inhibitory effect of epinephrine on TM cell survival is associated with NO production. NO-mediated apoptosis may be involved in this epinephrine-induced antiproliferative effect on TM cells.

Animals↗
PubMed2005

Inhibitory effect of tissue transglutaminase (tTG) antisense oligodeoxynucleotides on tTG expression in cultured bovine trabecular meshwork cells.

To study the effect of tTG fully phosphorothioated antisense oligodeoxynucleotides (tTG-ASDON) on tTG expression in cultured bovine trabecular meshwork cells (BTMCs) in vitro and explore a new treatment alternative for primary open angle glaucoma (POAG), the ASDON1 and ASDON2 complementary to the protein codogram region of tTG were designed, synthesized and phosphorothioated according to the secondary structure of tTG. The ASDON1 and ASDON2 were embedded in Lipofectamine and transfected into BTMCs. The untreated group served as negative controls. The expression of tTG in the mRNA and protein level were measured by semi-quantitative RT-PCR and immunohistochemical technique-Supervision method respectively. Our results showed that both the mRNA and the protein of tTG with tTG-ASDON and tTG-ASDON2 were significantly decreased as compared with that of the controls (P < 0.05). On the other hand, no significant difference was found between the ASDON1 group and the ASDON2 group. It is concluded that the expression of tTG mRNA and protein in cultured BTMC are down-regulated by tTG- ASDON. As a result, tTG-ASDON may be used for the treatment of POAG through the inhibitory effect on the expression of tTG.

Animals↗
PubMed1999

[Localization by immunogold of collagen VI, laminin and fibrillin in the trabecular meshwork of patients with glaucoma].

PURPOSE: To localize the collagen type VI, laminin et fibrillin in glaucomatous and non-glaucomatous trabecular meshworks. MATERIAL: Twenty-four trabeculectomy specimens from patients suffering of primary open angle glaucoma (POAG, 15 cases), pigmentary glaucoma (PG, 2 cases), pseudo-exfoliative glaucoma (PEG, 7 cases) and 2 non glaucomatous aged trabeculums of enucleated eyes. METHODS: Post-embedding immunogold indirect labelings on 4% paraformaldehyde-0.1% glutaraldehyde fixed and LRWhite embedded samples. RESULTS: Labeling of type VI collagen was observed on the 64 nm collagen fibers in all samples, less intensively on POAG or PG disorganised microfibril areas, and especially on PEG pseudo-exfoliative material deposits. Laminin labeling was strongly positive on healthy basal membranes and less intense on POAG and PG abnormal basal membranes. Fibrillin labeling was found on POAG or PG disorganized microfibril areas, especially around pigment granules, around 64 nm striated collagen fibers and with a mild intensity on POAG and PG juxtacanalicular microgranular substance areas. No labeling was found on pseudo-exfoliative substance deposits. CONCLUSION: Collagen type VI abundance in pseudo-exfoliative substance deposits could result from a fibrillogenesis abnormality. POAG and PG basal membrane ultrastructural abnormalities and weak laminin content could share the origin. The abundance of fibrillin in disorganized microfibrils could result from the chronic elevated tensile strength due to ocular hypertony.

Aged↗
PubMed2003

Effects of prostaglandin analogues on human ciliary muscle and trabecular meshwork cells.

PURPOSE: To determine the effects of prostaglandin F(2alpha) analogues on gene expression of human ciliary muscle (HCM) and trabecular meshwork (HTM) cells. METHODS: Cultures of HCM and HTM cells were established from five different donors treated for 9 days with 10 microg/mL of either latanoprost (free acid) or prostaglandin F(2alpha) ethanolamide and compared with control cells. The mRNA from the cells of the five individual donors was pooled and analyzed by using gene microarrays. Gene expression changes were confirmed by either real-time PCR or relative quantitative PCR. RESULTS: Approximately 12 genes showed a twofold or greater change in expression under experimental conditions. Four of these may alter outflow. Aquaporin-1 and versican were downregulated in the HCM, whereas IGF1 and fibroleukin were upregulated in HTM. Expression levels of TNFSF10 and promelanosome-concentrating hormone also increased in the treated HTM cells. The mRNA levels for the prostaglandin FP receptor were downregulated in the ciliary muscle cells. Optineurin and alphaB-crystallin levels remained unchanged, but myocilin in the HTM cells was decreased in some samples. CONCLUSIONS: Both analogues changed gene expression similarly in either HCM or HTM cells, but the changes appeared to be cell specific, perhaps indicating that other transcription factors are influential. Outflow of aqueous humor may be increased by the prostaglandin analogues by alterations in the extracellular matrix. Other changes may influence cellular metabolism, such as the increases in IGF1, tumor necrosis factor superfamily-10 and promelanosome-concentrating hormone.

Actins↗