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Biomedical subjects

E Lütjen-Drecoll

Publications and source records attributed to E Lütjen-Drecoll.

At least 19 recordsLinked to original sources
PubMed2001

Beta-adrenergic blocker therapy and the trabecular meshwork.

PURPOSE: To determine whether beta-adrenergic blocker (beta-blocker) therapy for glaucoma causes changes in the trabecular meshwork due to underperfusion. METHODS: Thirty-five eyes from 19 donors with primary open-angle glaucoma (POAG) were divided into three groups: eyes receiving beta-blocker therapy along with standard medications, eyes receiving standard medications but no beta-blockers, and eyes with elevated intraocular pressure but receiving no therapy. Transmission electron microscopy was used to assess the extracellular material of the cribriform region, the structure of the trabecular lamellae, and pigmentation of the trabecular cells. Six eyes from four normal donors were used as controls. RESULTS: No specific changes in the trabecular meshwork were found in eyes receiving beta-blocker therapy. The amount and composition of the extracellular matrix of the cribriform region and the morphology of the lamellae were similar among the three groups of eyes with POAG. Pigmentation of trabecular cells appeared to be a marker for aqueous flow, as significantly more cells contained pigment in regions of the meshwork with thin or normal lamellae than in regions with thickened and fused lamellae. These regions were variable around the circumference of the eye, and were similar between eyes with and without beta-Blocker therapy. CONCLUSION: beta-Blocker therapy could not be proven to cause underperfusion changes in the trabecular meshwork or other discernible effects. Preferential pathways for aqueous flow probably exist within regions of the trabecular meshwork, as evidenced by lamellar appearance and pigmentation of the adjacent trabecular cells.

Acetazolamide↗
PubMed2001

Transforming growth factor beta 2 levels in the aqueous humor in different types of glaucoma and the relation to filtering bleb development.

PURPOSE: To investigate the transforming growth factor beta 2 (TGF-beta 2) levels and total protein levels in the aqueous humor of eyes with different types of glaucoma [primary open-angle glaucoma (POAG), pseudoexfoliation glaucoma (PSX), juvenile glaucoma (JG)], and the relation to filtering bleb development after trabeculectomy. METHODS: Aqueous humor was collected at the beginning of surgery from 52 eyes with glaucoma (29 POAG eyes, 17 PSX eyes, 6 JG eyes) and from 29 control eyes that underwent cataract operation. TGF-beta 2 levels (intrinsically activated and total TGF-beta 2) using ELISA methods as well as total protein concentrations of the aqueous humor were determined. All preoperative clinical data of the glaucoma eyes (age, gender, IOP, previous treatment, type of surgery) were compared with the TGF-beta 2 levels. In 40 of these eyes, the postoperative follow-up (filtering bleb development, need for intervention, IOP) was correlated to the preoperatively determined TGF-beta 2 levels. RESULTS: TGF-beta 2 levels were increased in nearly half of the eyes with POAG and in most of the eyes with JG, but in eyes with PSX, TGF-beta 2 levels were within the normal range. No correlation between TGF-beta 2 levels and age, gender, IOP, previous treatment, or type of surgery, or between TGF-beta 2 levels and protein levels in aqueous humor, was found. Correlation between bleb formation and TGF-beta 2 levels revealed that all but two of the POAG eyes with good clinical outcome (type 1 bleb) had normal levels of activated TGF-beta 2. Of the 13 eyes that needed postoperative intervention (type 2 and type 3 bleb), 8 had high and 5 had normal TGF-beta 2 levels. CONCLUSIONS: PSX eyes differ from POAG and JG eyes not only by their clinical or biomicroscopic appearance, but also by their normal TGF-beta 2 levels in aqueous humor. The fact that most of the POAG eyes with favorable bleb development had normal TGF-beta 2 levels indicated that there might be some relationship between bleb formation and TGF-beta 2 levels. On the other hand, the fact that eyes with less favorable bleb development had both low and high TGF-beta 2 levels indicated that other factors are also involved in the scarring of the filtration bleb.

Adolescent↗
PubMed2001

Evaluation of the rhodopsin knockout mouse as a model of pure cone function.

PURPOSE: To determine a time window in the rhodopsin knockout (Rho(-/-)) mouse during which retinal function is already sufficiently developed but cone degeneration is not yet substantial, thus representing an all-cone retina. METHODS: Electroretinograms (ERGs) were obtained from 14 homozygous Rho(-/-) mice and eight C57Bl/6 control mice. The same individuals were tested every 7 days, beginning as early as postnatal day (P)14. The ERG protocols included flash and flicker stimuli, both under photopic and scotopic conditions. Retinal and choroidal morphology was observed in animals of comparable age. RESULTS: Functionally, the developmental phase lasted until postnatal week (PW)3 in both the Rho(-/-) mice and the control animals. During PW4 to 6, the Rho(-/-) mice showed a plateau in ERG parameters with normal or even supernormal cone responses and complete absence of rod contributions. At PW7, there was a marked onset of degeneration, which progressed so that no ERG signals were left at PW13, when the control eyes still had normal ERG responses. Microscopically, cone degeneration paralleled the functional changes, beginning at approximately PW6 and almost complete at PW13, whereas retinal pigment epithelium (RPE) and choroid did not show any abnormalities. CONCLUSIONS: From PW4 to 6, Rho(-/-) mice appear to have normal cone and no rod function. Despite the missing rod outer segment (OS), the structure of retina, RPE, and choroid remained unchanged. Therefore, the Rho(-/-) mice can serve during this age period as a model for pure cone function. Such a model is particularly useful to evaluate rod-cone interaction and to dissect rod- from cone-mediated signaling pathways in vivo.

Animals↗
PubMed2001

Retinal morphology and ERG response in the DBA/2NNia mouse model of angle-closure glaucoma.

PURPOSE: To document the time course of retinal dysfunction by scotopic electroretinography (ERG) and by quantitative morphology in eyes of the DBA/2NNia substrain of mouse (DBA) with inherited angle-closure glaucoma. METHODS: DBA and control C57BL/6J (C57) mice were studied by ERG recordings from 5 to 15 months of age, and by morphology from 1 to 14 months of age. Scotopic ERGs were simultaneously recorded from both eyes of dark-adapted anesthetized mice. Changes in the central neuronal retina were evaluated by quantitative morphometry performed on serial semithin sections of Epon-embedded eyes. RESULTS: When compared with normal C57 mice, DBA mice showed significant reductions of the a-wave and b-wave amplitudes by 7 to 8 months, and the decline continued as the animals aged. The b-wave implicit time in DBA mice showed a gradual prolongation beginning at 8 months of age, when compared with C57 mice. Logistic regression analyses revealed significant correlations in a- and b-wave amplitude reductions between ipsilateral and contralateral eyes of DBA mice at ages when ERG parameters were greatly altered. Morphologically, thinning of the whole retina was already evident in DBA mice at 4 months of age, but loss of ganglion cells and thinning of the outer plexiform layer were first seen in 7- to 8-month-old animals. These changes progressed to the end of the 13-month period studied. CONCLUSIONS: Progressive thinning of the outer retinal layers in DBA mice was found to correlate with decreases in ERG a- and b-wave amplitudes, both occurring from the age of 7 to 8 months onward. Similarities with the findings in human late-stage glaucomatous retinopathy indicate the relevance of this animal model in further glaucoma research.

Animals↗
PubMed2001

Glutathione peroxidase-1 deficiency leads to increased nuclear light scattering, membrane damage, and cataract formation in gene-knockout mice.

PURPOSE: Previous in vitro studies with transgenic and gene-knockout mice have shown that lenses with elevated levels of glutathione peroxidase (GPX)-1 activity are able to resist the cytotoxic effect of H(2)O(2), compared with normal lenses and lenses from GPX-1-deficient animals. The purpose of this study was to investigate the functional role of this enzyme in antioxidant mechanisms of lens in vivo by comparing lens changes of gene-knockout mice with age-matched control animals. METHODS: In vivo lens changes were monitored by slit lamp biomicroscopy, and enucleated lenses were examined under a stereomicroscope in gene-knockout animals and age-matched control animals ranging in age from 3 weeks to 18 months. Transmission (TEM) and confocal microscopy were performed on different regions of lenses after the mice were killed at various times. RESULTS: Slit lamp images showed an increase in nuclear light scattering (NLS) in gene-knockout mice compared with control animals. TEM revealed changes in the nucleus as early as 3 weeks of age by the appearance of waviness of fiber membranes. With increasing age, there was greater distortion of fiber membranes and distension of interfiber space at the apex of fiber cells compared with control mice. The changes in nuclear fiber membranes were even more dramatic, as observed by confocal microscopy, which was performed on thicker sections. In contrast to the changes in the lens nucleus, the morphology of the epithelium and superficial cortex remained unchanged in knockout animals during the same experimental period, consistent with slit lamp observations. Stereomicroscopy of ex vivo lenses demonstrated a significant increase in opacification in gene-knockout mice relative to control animals of the same age. This effect became evident in mice aged 5 to 9.9 months and persisted thereafter in older animals, resulting in mature cataracts after 15 months. CONCLUSIONS: The results demonstrate the critical role of GPX-1 in antioxidant defense mechanisms of the lens nucleus. The increased NLS appears to be associated with damage to fiber membranes in the nucleus, which is particularly susceptible to oxidative challenge because of the deficiency of GPX-1. It is suggested that the lens membrane changes in the knockout animals may be due to the formation of lipid peroxides, which serve as substrates for GPX-1. Cataract development in gene-knockout mice appeared to progress from focal opacities, apparent at an earlier age, to lamellar cataracts between 6 and 10 months, and finally to complete opacification in animals older than 15 months. This is the first reported phenotype in GPX-1-knockout mice.

Animals↗
PubMed2000

Transforming growth factor-beta: a growth factor inducing alpha B-crystallin expression in ciliary muscle cells.

BACKGROUND: In a recent study we showed that, in vitro, transforming growth factor-beta 2 (TGF-beta 2) induces alpha B-crystallin expression in cultured trabecular meshwork (TM) cells, but not in cultured fibroblasts. We assumed that alpha B-crystallin can be induced by TGF-beta 2 only if the cells are already expressing a basal level of the protein. In the present study we therefore treated cultured ciliary muscle (CM) cells constitutively expressing alpha B-crystallin and investigated the effect of TGF-beta on expression of alpha B-crystallin and the corresponding mRNA in these cells. MATERIAL AND METHODS: Monolayer cultures of third-passage CM cells from eyes of five human donors (12-73 years), being confluent for 7 days, were treated with 1.0 ng/ml TGF-beta 1 or TGF-beta 2. Induction of alpha B-crystallin and the related mRNA was investigated by immunofluorescence and by western and northern blot analysis. RESULTS: An increase in alpha B-crystallin mRNA was observed following treatment with TGF-beta. Actinomycin blocked the induction of alpha B-crystallin by the cytokine TGF-beta. Using western blotting the increase in alpha B-crystallin expression in CM cells was only small. CONCLUSION: These results confirm our assumption that induction of alpha B-crystallin by the cytokine TGF-beta depends on basal levels of the protein and its mRNA constitutively present within the cells. Comparison of the increase in alpha B-crystallin mRNA and protein expression indicate that post-transcriptional regulation mechanisms are responsible for these findings in CM cells.

Aged↗
PubMed2000

Efferent and afferent innervation of primate trabecular meshwork and scleral spur.

PURPOSE: To determine the correlation between nerve terminals and cells or extracellular matrix (ECM) components in different portions of the primate trabecular meshwork (TM) and scleral spur (SS). METHODS: Serial sagittal and tangential sections through the anterior segments of 10 cynomolgus monkey eyes and 12 human eyes were investigated immunohistochemically with antibodies against the vesicular acetylcholine transporter (VACHT), vasoactive intestinal polypeptide (VIP), tyrosine-hydroxylase (TH), neuropeptide Y (NPY), substance P (SP), calcitonin gene-related peptide (CGRP), and galanin (GAL) and with a reduced nicotinamide adenine dinucleotide phosphate-diaphorase (NADPHd) reaction. The distribution of the terminals was compared with that of alpha-smooth-muscle actin (SMA) staining in TM and SS. The relationship between terminals and adjacent cells or ECM components was also studied in ultrathin sections through the TM and SS of 11 monkey eyes cut in sagittal, tangential, and frontal planes. RESULTS: NADPHd-positive nerve terminals were present, especially in the outer portion of both human and monkey TM and in the SS. VACHT-immunoreactive (IR) fibers were found in human but not in monkey SS and TM. The fibers were most numerous in the elongated SS and posterior TM where most cells also stained for SMA. SP- and CGRP-IR nerve endings were also more numerous in the outer TM and SS than in the inner TM. Ultrastructurally, staining for SP was seen in nerve endings containing mitochondria and dense core vesicles and was in contact with the cribriform elastic network. In the posterior SS of monkey eyes were large terminals similar to those previously described in human eyes. CONCLUSIONS: The results show for the first time that in the primate TM and SS, there are cholinergic and nitrergic nerve terminals that could induce contraction and relaxation of TM and SS cells. Terminals in contact with the elastic-like network of the TM and containing SP-IR resemble afferent mechanoreceptor-like terminals in other parts of the body. These findings raise the possibility that the TM may have some ability to self-regulate aqueous humor outflow.

Actins↗
PubMed2000

Induction of tissue transglutaminase in the trabecular meshwork by TGF-beta1 and TGF-beta2.

PURPOSE: To study whether human trabecular meshwork (HTM) cells are capable of expressing and secreting tissue transglutaminase (tTgase), an enzyme cross-linking extracellular matrix (ECM) proteins, and whether tTgase and synthesis of cross-linked fibronectin are increased after treatment of HTM cells with transforming growth factor (TGF)-beta1 or -beta2. METHODS: Anterior segments of six normal human eyes were stained with antibodies to tTgase. Tissues from three eyes were analyzed for tTgase using Western blot analysis. Monolayer cultures of HTM cells from eyes of five human donors were treated with 1.0 ng/ml TGF-beta1, -beta2, or 5 X 10(-7) M dexamethasone (DEX) for 12 to 96 hours. Induction of tTgase was investigated by Western and Northern blot analysis. External tTgase activity was measured by the ability to form polymerized fibronectin and the incorporation of biotinylated cadaverine into fibronectin. RESULTS: Labeling for tTgase was observed throughout the entire HTM. Cultured HTM cells expressed tTgase intra- and extracellularly. Treatment of cultured HTM cells with TGF-beta1 and -beta2 increased the tTgase mRNA and protein levels, whereas DEX had no effect. TGF-beta-treated HTM cells showed a significant increase in polymerized and unpolymerized fibronectin. Incorporation of biotinylated cadaverine was markedly increased when HTM cells were treated with TGF-beta for 24 hours before seeding. CONCLUSIONS: The enzyme tTgase is expressed in the HTM and is inducible by TGF-beta1 or -beta2 in cultured HTM cells. Extracellular tTgase is able to polymerize fibronectin. Increased levels of TGF-beta2 in the aqueous humor may lead to an increase of tTgase expression and activity in the HTM, causing an increase of irreversibly cross-linked ECM proteins. This mechanism might play a role for the increased outflow resistance seen in glaucomatous eyes.

Adult↗
PubMed2000

AlphaB-crystallin in lacrimal gland duct and tears.

PURPOSE: To investigate alphaB-Crystallin expression and localization in the lacrimal gland and tear fluid. METHODS: Mouse, rat, porcine, monkey and human lacrimal gland samples were immuno-histochemically and immuno-electron-microscopically stained with various antibodies against alphaB-crystallin. Western- and Northern-blotting was performed to demonstrate the presence of alphaB-crystallin mRNA and protein. Human tear fluid was analyzed for the presence of alphaB-crystallin using dot blotting. RESULTS: alphaB-Crystallin is located in the lacrimal gland duct cells but not in the acini. Electron microscopically, the protein was frequently found in apical electron-dense granules of lacrimal duct cells, occasionally also in the duct lumina. Western blotting confirmed the presence of alphaB-crystallin in the lacrimal gland, Northern blot samples revealed the presence of alphaB-crystallin mRNA. In the human tear fluid, alphaB-crystallin was present in all samples investigated. CONCLUSIONS: We demonstrate for the first time that alphaB-crystallin is present in the lacrimal gland. Presence of the protein in apical secretory granules as well as presence in the tear fluid might indicate secretion of alphaB-crystallin into the tear fluid.

Aged↗
PubMed1999

Morphological changes of retinal pigment epithelium and choroid in rd-mice.

The sequence of degenerative changes in the retinal pigment epithelium (RPE) and the choroid of retinal degeneration (rd)-mice was studied in correlation with photoreceptor changes. Three weeks to 26-month-old animals were investigated using light and transmission electron microscopy, enzyme histochemistry and quantitative morphology. Changes in the choriocapillaris (CC) were additionally studied by scanning electron microscopy of corrosion cast preparations. In 3-week-old mice, in which most of the outer segments of photoreceptors in the central portion of the retina had disappeared but remnants of the cells were still present, the RPE was enlarged and showed elongated microvilli. In 8-week-old animals, the photoreceptors were completely absent in large areas of the posterior pole region. In these areas the RPE was also completely lost. Quantitative evaluation performed in histological serial sections showed that loss of RPE measured as length of RPE-free Bruch's membrane, continuously increased up to the age of 20 months. In 8-week-old animals, CC adjacent to degenerating RPE showed loss of fenestration. In 10-week-old animals, the CC disappeared in those areas where the RPE was already lacking. The loss of CC increased with increasing age and in 20-month-old animals 5-10% of the entire CC was lacking. Loss of the related arterioles and nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d)-positive nerve fibers occurred only in approximately 2-year-old rd-mice. Compared to other animal models, RPE and CC defects in rd-mice are relatively large. The rd-mice might therefore provide a good tool to study factors involved in CC degeneration.

Animals↗
PubMed1999

Functional morphology of the trabecular meshwork in primate eyes.

The trabecular meshwork forms most of the resistance to aqueous humor outflow needed for maintenance of a pressure gradient between intraocular pressure of approximately 17 mmHg and venous pressure of approximately 10 mmHg. The composition of the extracellular material in the subendothelial or cribriform layer seems to be mainly responsible for outflow resistance. The aqueous humor pathways through the subendothelial layer can be influenced by ciliary muscle contraction and presumably also by contractile elements recently found both in trabecular meshwork and scleral spur. Pharmacologically induced disconnection of inner wall and cribriform cells leads to wash out of extracellular material through breaks of the endothelial lining of Schlemm's canal and to increase of outflow facility. In glaucomatous eyes the resistance to aqueous humor outflow is increased due to an increase in different forms of extracellular material deposited within the cribriform layer. The amount of this newly developed extracellular material is correlated with loss of axons in the optic nerve, indicating that a common factor is responsible for both changes. To investigate the effect of various factors on the biology of trabecular cells monolayer cultures derived from cribriform and corneoscleral trabecular meshwork have been established. The two cell lines can be differentiated because cribriform cells in vivo as in vitro stain for alphabeta-crystallin whereas the corneoscleral cells remain unstained. The effect of TGFbeta, a growth factor increased in aqueous humor of glaucomatous eyes and glycocorticoids on trabecular meshwork cells show typical changes in formation of extracellular matrix components and of stress proteins. Dexamethasone and oxidative damage also lead to increase of trabecular meshwork inducible glucocorticoid response (TIGR) protein. A mutation of the TIGR-gene family has recently been found in families with juvenile and chronic simple glaucoma. Future research has to clarify the significance of these genetic factors for the pathophysiology of glaucoma and the role of trabecular cell activity in this respect.

Animals↗
PubMed1999

AlphaB-crystallin in the trabecular meshwork is inducible by transforming growth factor-beta.

PURPOSE: Because in glaucomatous eyes transforming growth factor-beta (TGF-beta) and alphaB-crystallin are increased in the anterior eye segment, the effect of TGF-beta1 and TGF-beta2 on the expression of alphaB-crystallin and its corresponding mRNA was studied in human trabecular meshwork (TM) cells. METHODS: Monolayer cultures of "cribriform" and "corneoscleral" TM cells of 5 human donors (12-73 years of age) were treated with either 1.0 ng/ml TGF-beta1, TGF-alpha2, or 5 X 10(-7) dexamethasone (DEX) for 12 to 96 hours. Induction of alphaB-crystallin and the related mRNA was investigated by western and northern blot analyses. For comparison, human foreskin fibroblasts (HFF) and NIH 3T3 cells were treated in the same way as the TM cells. RESULTS: An increase of alphaB-crystallin mRNA was observed after treatment of TM cells with TGF-beta1 and TGF-beta2, whereas DEX had no effect. In the cribriform TM cells with a high basal level, the enhancement ranged between 2 and 3 times; whereas in the corneoscleral TM cells alphaB-crystallin mRNA increased between 5 and 6 times. Using western blot analysis, the increase of alphaB-crystallin expression in the cribriform TM cells was only small compared with the significant increase in the corneoscleral TM cells. Treatment of HFF and NIH 3T3 cells with TGF-beta did not induce alphaB-crystallin mRNA. CONCLUSIONS: This is the first time to show that alphaB-crystallin is not only induced by stress factors but also by TGF-beta in TM cell cultures. The difference in induction of mRNA and protein seems to be dependent on alphaB-crystallin concentration before treatment.

Aged↗
PubMed1999

Loss of anterior chamber-associated immune deviation (ACAID) in aged retinal degeneration (rd) mice.

PURPOSE: To determine whether the capacity to induce ACAID by antigen injection into the anterior chamber is altered in animals with genetically determined retinal degeneration and increased age. METHODS: Anterior chamber-associated immune deviation (ACAID) induced by injection of ovalbumin into the anterior chamber of the eye was studied in three rodent strains with different forms of hereditary retinal degeneration (Royal College of Surgeon [RCS] rats, retinal degeneration [rd] mice, and Norrie-Disease [ND] mice) and in different age groups (age range, 1-23 months). The data were compared with those of age-matched controls. Aqueous humors of rd mice, RCS rats, and age-matched congenic controls were investigated for concentrations of transforming growth factor-beta2 (TGF-beta2) using enzyme-linked immunosorbent assay. RESULTS: ACAID was readily induced in RCS rats and ND mice irrespective of amount of retinal degeneration or aging. In rd mice ACAID could be induced in young animals but not in animals more than 12 months of age. In old rd mice, loss of ACAID was accompanied by a marked reduction in total TGF-beta2 levels in aqueous humor. CONCLUSIONS: Rd mice more than 1 year of age lose the capacity of the anterior chamber to support the induction of ACAID by intracameral injection of soluble protein antigen. Because loss of ACAID correlated with a decrease in TGF-beta2 concentration in aqueous humor, it is proposed that eyes of rd mice are unable to maintain an immunosuppressive microenvironment necessary for ACAID.

Aging↗
PubMed1998

Classification of human scleral spur cells in monolayer culture.

Aqueous humor outflow in primate eyes can be facilitated by ciliary muscle contraction, thereby widening fluid pathways through the trabecular meshwork. Recently in the scleral spur smooth muscle (sm) alpha-actin positive myofibroblast-like cells have been described which are in contact with the elastic fiber system of both the spur and trabecular meshwork. In the vicinity of these cells nerve terminals have been described. It is speculated that contraction of scleral spur cells can facilitate aqueous humor outflow, too. To provide a tool for further physiological and pharmacological studies monolayer cell cultures of human scleral spur have been established and characterized. For this purpose, cells derived from scleral spur, outer and inner trabecular meshwork and ciliary muscle tips from 7 donor eyes (43-87 years-old respectively, obtained 3-7 h post mortem) were grown in tissue culture medium and the different monolayer cells classified by their growth characteristics, and by immunohistochemical staining for vimentin, alpha-sm-actin, desmin, and alpha B-crystallin, respectively. In addition, the presence of alpha B-crystallin mRNA and desmin mRNA was verified using the polymerase chain reaction (PCR)-method. We were able to characterize and distinguish human scleral spur cells from adjacent ciliary muscle and trabecular meshwork cells. Scleral spur cells (SPC) grew slower than ciliary muscle cells (CMC) but much faster than trabecular meshwork cells (TMC). All cells showed the same staining characteristics in vitro as they did in vivo. Scleral spur cells stained for vimentin and alpha-sm-actin, but not for desmin and alpha B-crystallin. The corresponding mRNAs of the latter two proteins could not be detected by PCR in the spur cells. Cells grew out from all donor eyes so that they actually provide a tool for further experimental studies.

Cell Culture Techniques↗
PubMed1998

Changes in choroidal innervation in Royal College of Surgeons rats with hereditary retinal degeneration.

In Royal College of Surgeons (RCS) rats with hereditary retinal degeneration loss of retinal pigmented epithelium (RPE) and choriocapillaris is most pronounced in the upper-temporal quadrant. To investigate whether changes in choroidal vasodilative innervation might be involved in the RPE degeneration, we analyzed whole mount preparations of the retina and choroid stained for nitric oxide synthase and for NADPH-diaphorase (d) of 19 dystrophic RCS rats and 24 age-matched congenic controls of different age groups. Density of NADPH-d-positive nerve fibers was quantitatively evaluated in the upper-temporal and lower-nasal quadrant. Our results revealed that even in control animals there were much less positively stained nerve fibers in the upper-temporal than in the lower-nasal quadrant. Nerve fiber density in both quadrants increased for up to 3 months and remained nearly constant throughout life. In the dystrophic animals up to 3 months of age nerve fiber density was similar to that seen in the controls. In dystrophic animals older than 3 months nerve fiber density in the upper-temporal quadrant decreased significantly, whereas density in the lower-nasal quadrant revealed nearly the same values as in the age-matched controls. Decrease of NADPH-d stained nerve fibers in this quadrant occurred prior to the vascular changes in the choriocapillaris. In the retina of RCS dystrophic rats an increase of NADPH-d-positive amacrine cells was found only in 3-month-old animals. Most of these cells were located in the vicinity of irregularly arranged branches of the central retinal artery. In animals 5 months of age and older the number of cells decreased to the same values found in controls, so that we assume that increase of NADPH-d-positive amacrine cells is involved in capillary degeneration or sprouting.

Animals↗
PubMed1998

Acute and chronic structural effects of pilocarpine on monkey outflow tissues.

PURPOSE: Determine the effects of supraclinical topical doses of pilocarpine on the structure of the trabecular meshwork (TM), ciliary muscle (CM), and ciliary processes in monkeys. METHODS: Cynomolgus monkeys received topical pilocarpine hydrochloride doses of 1 to 2 mg unilaterally once or twice daily for 1 to 211 days. Both eyes were examined by light and electron microscopy. RESULTS: After 1 dose, the TM was expanded and the flow pathways open. Some elastic anterior CM tendons were disconnected from the muscle tips and/or the tips themselves were disrupted; macrophage-like cells accumulated in these regions. In eyes that had long-term treatment, scar tissue at the muscle tips and disruption of myofibrils within muscle cells indicated regions of previous disconnection. Most collagen tendons inserting into the peripheral cornea were unaffected. With increasing treatment duration in younger monkeys, there was anteroposterior shortening of Schlemm's canal, TM densification due to collapse, and increased cellularity in the subendothelial region of Schlemm's canal. TM densification and Schlemm's canal shortening were not found in older monkeys, implicating posterior movement of the elastic young limbal region induced by strong CM contraction, rather than pilocarpine toxicity. In the ciliary body we found vasodilation, Greeff's vesicles, and blood-aqueous barrier breakdown in the anterior ciliary processes and vasodilation, edema, and round-cell infiltration in the posterior pars plana. CONCLUSIONS: Large pilocarpine doses induce morphologic changes in the monkey anterior segment, likely consequent to intense CM contraction. Changes in the TM and Schlemm's canal are seen only in young monkeys, apparently owing to mechanical deformation of the elastic limbal region.

Animals↗