Biomedical subjects

Teruo Nishida

Publications and source records attributed to Teruo Nishida.

At least 55 records · Page 3Linked to original sources

PubMed2004

Inhibitory effects of anti-glaucoma drugs on corneal epithelial migration in a rabbit organ culture system.

PURPOSE: The possible effects of the anti-glaucoma drugs latanoprost, timolol maleate, and nipradilol on corneal epithelial wound healing were investigated in a rabbit organ culture system. METHODS: Corneal blocks (approximately 2 x 4 mm) isolated from albino Japanese rabbits were cultured for 24 hours in medium containing various concentrations (0.01 to 10 mM) of latanoprost, timolol maleate, or nipradilol. The specimens were then fixed and embedded in paraffin, and thin sections were prepared. After the removal of paraffin, the sections were stained with hematoxylin-eosin and observed under a light microscope. Images were recorded digitally with a CCD camera, and the distance over which the epithelium had migrated down the sides of each block was calculated with a computer-assisted morphometric program. RESULTS: Corneal epithelial migration was inhibited by each anti-glaucoma drug in a dose-dependent manner. The 50% inhibitory doses (ID50) for latanoprost, timolol maleate, and nipradilol were 0.362, 0.585, and 4.89 mM, respectively. Relative to the concentrations present in commercially available eyedrops, ID50 corresponded to concentration ratios for timolol, nipradilol, and latanoprost were of 0.037, 0.64 and 3.1, respectively. CONCLUSIONS: The anti-glaucoma drugs examined inhibited corneal epithelial migration in a rabbit organ culture system. However, it is unlikely that the corneal surface would be exposed to these agents at inhibitory concentrations for a prolonged period in the normal clinical setting.

Animals↗

PubMed2004

Novel complex GUCY2D mutation in Japanese family with cone-rod dystrophy.

PURPOSE: All mutations in the retinal guanylate cyclase gene (GUCY2D) that causes autosomal dominant cone-rod dystrophy (CORD) are associated with an amino acid substitution in codon 838. A novel heterozygous complex missense mutation of I915T and G917R in the GUCY2D gene was found in a Japanese family with autosomal dominant CORD. The clinical features associated with this mutation were described. METHODS: Blood samples were collected from 27 patients with cone-rod or cone dystrophies and from 11 patients with macular dystrophy. Genomic DNA was extracted from peripheral leukocytes. All 18 coding exons of the GUCY2D gene were directly sequenced. The PCR product carrying a novel mutation was subcloned, and each allele was sequenced. A complete ophthalmologic examination was performed in members of the family with the novel mutation. RESULTS: A novel heterozygous complex missense mutation of T2817C and G2822C that would predict I915T and G917R amino acid substitutions, respectively, was found in an autosomal dominant CORD family. The two nucleotide changes were located on the same allele, and segregated with the disease. Two other known missense mutations of R838H and R838C were found in two other CORD families. The clinical phenotype associated with the novel mutation was similar to that with the Arg838 mutations. CONCLUSIONS: A heterozygous complex mutation of I915T and G917R in the GUCY2D gene caused autosomal dominant CORD, indicating that a heterozygous mutation that does not include a codon 838 substitution can lead to this ocular phenotype.

Adult↗

PubMed2004

Role of the C domain of IGFs in synergistic promotion, with a substance P-derived peptide, of rabbit corneal epithelial wound healing.

PURPOSE: Insulin-like growth factors (IGFs) and either substance P (SP) or an SP-derived peptide (FGLM-amide) synergistically facilitate corneal epithelial wound healing in vitro and in vivo. The mechanism of this synergism and the clinical potential of these agents were further investigated by determination of the relevant functional domain of IGFs. METHODS: The effects of IGF-derived peptides on corneal epithelial cell migration were evaluated with the rabbit cornea in an organ culture system. Corneal epithelial wound closure in vivo was also evaluated in rabbits after epithelial debridement with n-heptanol. RESULTS: In the presence of FGLM-amide, peptides corresponding to the C domain of IGF-1 or -2 significantly promoted corneal epithelial migration in vitro to an extent similar to that apparent with the full-length molecules. In contrast, peptides corresponding to the D domain of these growth factors had no such effect. Mutation of serine-34 in the C domain of IGF-1 to alanine abolished the synergistic effect with FGLM-amide on corneal epithelial migration. The C peptide of proinsulin did not affect corneal epithelial migration in the absence or presence of FGLM-amide. The administration of eye drops containing both the C-domain peptide of IGF-1 and FGLM-amide significantly promoted corneal epithelial wound closure in vivo. CONCLUSIONS: The C domain of IGF-1 or -2, for which no biological function has previously been identified, is essential for the synergistic effect of these growth factors with SP on corneal epithelial migration.

Aged↗

PubMed2004

Dexamethasone inhibition of IL-1-induced collagen degradation by corneal fibroblasts in three-dimensional culture.

PURPOSE: Corticosteroids regulate the functions of inflammatory cells. The purpose of the present study was to investigate the effect of dexamethasone on collagen degradation by corneal fibroblasts, an underlying cause of corneal ulceration. METHODS: Rabbit corneal fibroblasts were cultured in three-dimensional gels of type I collagen and in the absence or presence of IL-1beta or dexamethasone. The extent of collagen degradation was determined by measurement of the amount of hydroxyproline generated by acid-heat hydrolysis of culture supernatants. The expression of matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) was evaluated by immunoblot analysis, gelatin zymography, and reverse transcription and real-time polymerase chain reaction. The phosphorylation of mitogen-activated protein kinases (MAPKs) in corneal fibroblasts was assessed by immunoblot analysis. RESULTS: Dexamethasone inhibited IL-1beta-induced collagen degradation by corneal fibroblasts in a dose-dependent manner. Both the synthesis and activation of MMPs and the expression of TIMPs were inhibited by dexamethasone, as was the activity of plasmin in culture supernatants. Dexamethasone also inhibited the IL-1beta-induced phosphorylation of the MAPKs extracellular signal-regulated kinase (ERK) and c-Jun N-terminal kinase (JNK), but not that of p38. CONCLUSIONS: Dexamethasone exerted multiple effects on the MMP-TIMP system in corneal fibroblasts and thereby inhibited IL-1beta-induced collagen degradation by these cells. Inhibition of the IL-1beta-induced activation of ERK and JNK may contribute to these effects of dexamethasone.

Animals↗

PubMed2003

A novel grading method for superficial punctate keratopathy magnitude and its correlation with corneal epithelial permeability.

OBJECTIVES: To propose a novel grading method for superficial punctate keratopathy (SPK) magnitude and to examine the quantitativeness of the method. METHODS: In 351 eyes diagnosed as having dry eye syndrome, SPK was graded as follows. After fluorescein staining, the total sum of the area of SPK was graded from A0 through A3, and the density was graded from D0 through D3. The grading was represented as the combination of the area and density grades. The correlation between the SPK grade and the corneal epithelial permeability to fluorescence, measured using an anterior fluorophotometer, was analyzed in the 351 eyes. MAIN OUTCOME MEASURES: The correlation between the fluorescein concentration in the cornea and the sum of the area and density grades. RESULTS: The higher the density and area grades, the higher the fluorescein concentration, except for A3D2. There was a clear exponential correlation between the sum of the area and density grades and the fluorescein concentration in the cornea, measured using an anterior fluorophotometer. The regression curve was y = 61.2e(0.59x), where y is the fluorescein concentration (nanograms per milliliter), and x is the sum of the area and density grades (P<.001). CONCLUSIONS: The SPK grade is positively correlated with the corneal epithelial permeability to fluorescence, measured using an anterior fluorophotometer. Our results indicate that this grading method can be clinically useful.

Corneal Diseases↗

PubMed2003

IL-4-induced cell proliferation and production of extracellular matrix proteins in human conjunctival fibroblasts.

Giant papillae, characteristic lesions of vernal keratoconjunctivitis, are formed as a result of the proliferation of conjunctival fibroblasts, the deposition of extracellular matrix, and the infiltration of inflammatory cells. The concentration of interleukin (IL)-4 is also increased in the tear fluid of individuals with ocular allergic diseases. The possible role of IL-4 in the development of giant papillae was investigated by examining the effects of this cytokine on cultured human conjunctival fibroblasts. Reverse transcription and polymerase chain reaction analysis revealed the presence of transcripts encoding the IL-4 receptor alpha chain in these cells, and flow cytometry demonstrated the expression of this protein on the cell surface. IL-4 induced the proliferation of conjunctival fibroblasts in a concentration-dependent manner, and this effect was inhibited by neutralizing antibodies to the IL-4 receptor. Enzyme immunoassays revealed that IL-4 also increased in a concentration-dependent manner the amounts of procollagen type I C-peptide and fibronectin released into the culture supernatant by conjunctival fibroblasts. A whole-cell enzyme-linked immunosorbent assay showed that IL-4 increased the deposition of collagen type III by conjunctival fibroblasts. Furthermore, reverse transcription combined with real-time polymerase chain reaction analysis revealed that IL-4 increased the abundance of collagen type III mRNA in these cells. These results demonstrate that human conjunctival fibroblasts express receptors for IL-4, and that IL-4 stimulates both the proliferation of and the production of extracellular matrix proteins by these cells. These effects of IL-4 might contribute to the formation of giant papillae in individuals with vernal keratoconjunctivitis.

Cell Division↗

PubMed2003

Recovery of corneal sensation after myopic correction by laser in situ keratomileusis with a nasal or superior hinge.

PURPOSE: To measure corneal sensitivity after laser in situ keratomileusis (LASIK) to determine the time required for recovery of this parameter. SETTING: Ohshima Hospital of Ophthalmology, Fukuoka, Japan. METHODS: Corneal sensation was measured with a Cochet-Bonnet-type esthesiometer in 75 patients before and 1, 3, 6, and 12 months after correction of myopia by photorefractive keratectomy (n = 21) or LASIK (n = 54). RESULTS: Photorefractive keratectomy did not affect corneal sensation. In the LASIK group, a large and significant decrease in corneal sensitivity was apparent at 1 month (P<.05). Although corneal sensitivity appeared to have recovered slightly at 3 months, it remained significantly decreased (P<.05). By 6 or 12 months, the corneal sensitivity in LASIK patients was not statistically different from the preoperative values in the study patients. A significantly greater decrease in corneal sensitivity was apparent in the LASIK patients with a nasal hinge than in those with a superior hinge (F = 7.54, P<.01). Corneal sensitivity was in the normal range in 31.5% of LASIK patients at 3 months and in 57.4% and 82.1% at 6 and 12 months, respectively. CONCLUSION: Recovery of corneal sensation had begun 3 months after LASIK and appeared complete after 12 months.

Adolescent↗

PubMed2003

Cell-matrix and cell-cell interactions during corneal epithelial wound healing.

The corneal epithelium serves as a barrier and contributes to the maintenance of corneal transparency and rigidity. In most instances, corneal epithelial defects caused by simple injury are resurfaced promptly. However, in individuals with certain clinical conditions, such as herpes simplex virus infection, neurotrophic keratopathy or diabetic keratopathy, corneal epithelial defects persist and do not respond to conventional treatment regimens because of delayed epithelial wound healing. After the corneal epithelium is removed by injury, the remaining epithelial cells migrate over the denuded surface of the cornea in a manner that is dependent both on the interaction of the cells with the underlying substrate and on cell-cell adhesion. In this review, we describe the specific roles of cell-matrix and cell-cell interactions during the course of corneal epithelial wound healing. The clinical implications of the basic research findings are also discussed.

Animals↗

PubMed2003

Differential expression of thymus- and activation-regulated chemokine (CCL17) and macrophage-derived chemokine (CCL22) by human fibroblasts from cornea, skin, and lung.

BACKGROUND: Allergic diseases of the ocular surface, skin, and lung are triggered by T(H)2 cells, which are recruited by thymus- and activation-regulated chemokine (TARC; CCL17) and macrophage-derived chemokine (MDC; CCL22). Resident fibroblasts are thought to contribute to inflammatory cell infiltration through chemokine production. OBJECTIVE: We sought to provide insight into the clinical differences apparent among these allergic diseases of the eye, skin, and lung, and we compared the abilities of corneal, dermal, and lung fibroblasts to produce TARC and MDC. METHODS: The amounts of chemokines released into the culture supernatant were determined by means of ELISA, and the intracellular abundance of chemokine mRNAs was quantitated by means of reverse transcription and real-time PCR analysis. RESULTS: Neither TNF-alpha, IFN-gamma, IL-4, nor IL-13 alone induced the release of TARC from or affected the amount of TARC mRNA in corneal, dermal, or lung fibroblasts. The combination of TNF-alpha with either IL-4 or IL-13, however, markedly increased both TARC release and the abundance of TARC mRNA in corneal and dermal fibroblasts, but not in lung fibroblasts. Neither MDC release nor MDC mRNA was detected in any of the 3 types of fibroblasts stimulated with any of the cytokines examined. CONCLUSION: These results indicate that cytokine regulation of TARC expression differs among fibroblasts derived from the cornea, skin, or lung. Corneal and dermal fibroblasts might thus be important sources of TARC during allergic inflammation.

Cells, Cultured↗

PubMed2003

Correlation of corneal sensation, but not of basal or reflex tear secretion, with the stage of diabetic retinopathy.

PURPOSE: To examine the possible relation between corneal sensation or tear secretion and the stage of diabetic retinopathy in diabetic patients. METHODS: Total reflex or basal tear secretion and corneal sensation were determined in 95 patients with type II diabetes mellitus and 58 nondiabetic control subjects. Tear secretion was measured by the Schirmer test and corneal sensation with a Cochet-Bonnet esthesiometer. RESULTS: Corneal sensation and total or reflex tear secretion were significantly reduced in diabetic patients compared with nondiabetic controls. The loss of corneal sensation, but not that of tear secretion, was significantly correlated with stage of diabetic retinopathy in diabetic patients who were diagnosed with no diabetic retinopathy, simple diabetic retinopathy, preproliferative retinopathy, or proliferative retinopathy. CONCLUSION: Both corneal sensation and total or reflex tear secretion are reduced in individuals with diabetes. The decrease in corneal sensation, but not that in each tear secretion, was correlated with the stage of diabetic retinopathy. Given that loss of corneal sensation is a manifestation of diabetic polyneuropathy, these results are consistent with the notion that both diabetic retinopathy and polyneuropathy result from a basement membrane abnormality.

Adult↗

PubMed2003

Potentiation by cyclic AMP of the stimulatory effect of epidermal growth factor on corneal epithelial migration.

PURPOSE: To provide insight into the mechanism by which epidermal growth factor (EGF) stimulates corneal epithelial migration, we investigated the possible interaction between EGF and cyclic AMP (cAMP) signaling pathways during epithelial migration with an organ culture system for the rabbit cornea. METHODS: Rabbit corneal blocks were cultured in the absence or presence of various agents for 24 hours and were then fixed, dehydrated, embedded in paraffin, sectioned, and stained with hematoxylin-eosin. The path length of epithelial migration was measured on light micrographs of the stained sections. RESULTS: Epidermal growth factor alone stimulated corneal epithelial migration in a dose-dependent manner. In contrast, neither of two cell-permeable cAMP analogs, dibutyryl cAMP and 8-bromo cAMP, affected epithelial migration at concentrations up to 1 mM. In the presence of EGF (10 ng/mL), however, each of the two cAMP derivatives increased the extent of epithelial migration in a concentration-dependent manner. Neither the adenylate cyclase activator forskolin nor the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine alone affected epithelial migration. However, each of these two agents potentiated the stimulatory effect of EGF on this process. The stimulatory effects of fibronectin, hyaluronan, and interleukin-6 on corneal epithelial migration were not modified by either dibutyryl cAMP or 3-isobutyl-1-methylxanthine. CONCLUSION: These results demonstrate that cAMP potentiates the stimulation of corneal epithelial migration by EGF in vitro, suggesting that endogenous cAMP might function as a modulator of epithelial wound healing promoted by this growth factor in vivo.

1-Methyl-3-isobutylxanthine↗

PubMed2003

Comparison of confocal biomicroscopy and noncontact specular microscopy for evaluation of the corneal endothelium.

PURPOSE: To compare the clinical efficacy of confocal biomicroscopy with that of noncontact specular microscopy for the evaluation of the corneal endothelium. METHODS: The corneal endothelium was examined in 14 normal subjects (28 eyes) and in 6 patients (11 eyes) with Fuchs corneal endothelial dystrophy using a noncontact specular microscope (SP-2000P, Topcon, Japan) and a confocal biomicroscope (ConfoScan, Tomey, Japan). The images and the calculated densities of corneal endothelial cells obtained by the 2 techniques were compared. RESULTS: For normal subjects, the images of corneal endothelial cells obtained by the 2 techniques were almost identical, although the density of these cells determined by confocal biomicroscopy (2916 +/- 334 cells/mm2) was slightly higher than that determined by noncontact specular microscopy (2765 +/- 323 cells/mm2). In contrast, whereas clear images of corneal endothelial cells, allowing the determination of cell density, were obtained for all 11 eyes of the patient group by confocal biomicroscopy, clear images were obtained for only 4 of these 11 eyes (36.4%) by noncontact specular microscopy. CONCLUSION: Both noncontact specular microscopy and confocal biomicroscopy revealed the shapes and number of endothelial cells in the normal cornea. However, for corneas with Fuchs dystrophy, clear images were obtained only by confocal biomicroscopy. Confocal biomicroscopy is thus an effective tool for evaluation of the diseased corneal endothelium.

Adult↗

PubMed2003

Synergistic effect of TNF-alpha and either IL-4 or IL-13 on VCAM-1 expression by cultured human corneal fibroblasts.

PURPOSE: To examine the role of corneal fibroblasts in the pathogenesis of vernal keratoconjunctivitis, we investigated the effects of tumor necrosis factor (TNF)-alpha, interleukin (IL)-4, and IL-13 on the expression of vascular cell adhesion molecule (VCAM)-1 by cultured human corneal fibroblasts. METHODS: Cultured human corneal fibroblasts were incubated with various combinations and concentrations of TNF-alpha, IL-4, and IL-13. The cell surface expression of VCAM-1 was subsequently evaluated by whole-cell enzyme-linked immunosorbent assay and immunocytochemistry, and the abundance of VCAM-1 mRNA in cell lysates was determined by quantitative reverse transcription and polymerase chain reaction analysis. RESULTS: Corneal fibroblasts incubated in the absence of cytokines exhibited minimal expression of VCAM-1. Whereas incubation of the cells with TNF-alpha, IL-4, or IL-13 alone, or with the combination of IL-4 and IL-13, induced only a small increase in VCAM-1 expression, exposure of the cells to TNF-alpha in combination with either IL-4 or IL-13 resulted in a marked synergistic increase in expression of this adhesion molecule that was both time and dose dependent. The abundance of VCAM-1 mRNA in corneal fibroblasts was also increased in a synergistic manner by incubation of the cells with TNF-alpha together with either IL-4 or IL-13. CONCLUSION: Stimulation of human corneal fibroblasts with the combination of TNF-alpha and either IL-4 or IL-13 resulted in synergistic increases in both the abundance of VCAM-1 mRNA and the cell surface expression of VCAM-1 protein. This cytokine-induced increase in VCAM-1 expression by corneal fibroblasts may contribute to eosinophil infiltration in corneal lesions associated with vernal keratoconjunctivitis.

Cells, Cultured↗

PubMed2003

Substance P in human tears.

PURPOSE: To determine the levels and biochemical characteristics of substance P-like immunoreactivity (SPLI) in human tears and ascertain whether substance P (SP) concentrations in tears reflect the condition of the ocular surface. METHODS: Unstimulated tears were collected with a micropipette. Tear samples were partially purified using C-18 cartridges. Levels of SPLI in purified samples were measured using an enzyme immunoassay (EIA). For biochemical characterization of SPLI, tear extracts were fractionated using high-performance liquid chromatography (HPLC); each fraction was then subjected to EIA. To determine the catabolism of SP in tears, synthetic SP was incubated in medium containing pooled tears and then analyzed using HPLC. RESULTS: The concentration of SPLI in normal human tears was 306.0 +/- 96.5 pg/mL (mean +/- SD, range 148-555 pg/mL). Levels of SPLI did not vary significantly by age or gender. Concentrations of SPLI in tears from eyes with unilateral corneal hypesthesia were lower than those in tears from contralateral healthy eyes. Diclofenac sodium eye drops reduced concentrations of prostaglandin E2 and SPLI in tears. Analysis using HPLC indicated that five different substances contributed to SPLI in tears and that SP was broken down into several fragments, including SP(8-11), by enzymes present in tears. CONCLUSIONS: Substance P is a normal component of human tears. Levels of SPLI in tears might reflect the denervated status of the ocular surface. Substance P is catabolized by degradative enzymes in tears to maintain the ocular surface by exerting the trophic effects of SP while avoiding undesirable effects.

Administration, Topical↗

PubMed2003

Restoration of corneal epithelial barrier function and wound healing by substance P and IGF-1 in rats with capsaicin-induced neurotrophic keratopathy.

PURPOSE: To investigate the effects of topical application of the combination of substance P (SP) and insulin-like growth factor (IGF)-1 on corneal epithelial barrier function and epithelial wound closure in rats with capsaicin-induced neurotrophic keratopathy. METHODS: Neonatal rats were injected subcutaneously with a single dose of capsaicin to induce neurotrophic keratopathy. Corneal epithelial barrier function was evaluated with an anterior fluorophotometer. Tear fluid secretion was measured by the Schirmer test. Corneal epithelial wound healing was determined by measurement of the size of the epithelial defect after debridement of the entire epithelium. The combination of SP (1 mM) and IGF-1 (1 micro g/mL) in phosphate-buffered saline was administered in eye drops six times daily. RESULTS: Corneal epithelial barrier function was impaired and corneal epithelial wound healing was delayed in rats injected with capsaicin. The application of eye drops containing the combination of SP and IGF-1 to capsaicin-injected rats resulted in a significant improvement in corneal epithelial barrier function compared with that apparent in capsaicin-injected animals that received eye drops containing vehicle alone. Such treatment with SP and IGF-1 also significantly increased the rate of corneal epithelial wound closure in capsaicin-injected animals. CONCLUSIONS: Topical application of the combination of SP and IGF-1 improved both corneal epithelial barrier function and epithelial wound healing in an animal model of neurotrophic keratopathy.

Administration, Topical↗

PubMed2003

Up-regulation of urokinase-type plasminogen activator in corneal epithelial cells induced by wounding.

PURPOSE: To investigate the possible role of urokinase-type plasminogen activator (uPA) in corneal epithelial wound healing by examining its expression both in the rabbit corneal epithelium in situ and in rabbit corneal epithelial (RCE) cells in vitro. METHODS: The rabbit cornea was subjected to mechanical wounding, and frozen sections of the tissue were subsequently prepared and subjected both to immunostaining with antibodies to uPA and to in situ zymography for the detection of PA activity. RCE cell monolayers were also subjected to scrape wounding, after which they were immunostained for uPA. The amounts of uPA protein in the culture medium and of uPA mRNA in cell lysates were also determined by enzyme-linked immunosorbent assay and by reverse transcription and real-time quantitative polymerase chain reaction analysis, respectively. RESULTS: Immunostaining and in situ zymography of the wounded cornea revealed that uPA was restricted to the leading edge of the migrating corneal epithelium. In contrast, tissue-type PA was expressed throughout the corneal epithelium. Scraping of RCE cell monolayers induced the expression of uPA in the migrating cells at the wound edge. The amount of uPA in the culture medium of RCE cells increased with the number of scrape wounds applied. Wounding also induced a time-dependent increase in the abundance of uPA mRNA in the cell monolayers. The migration of RCE cells was inhibited by antibodies to uPA. CONCLUSIONS: Mechanical wounding induces up-regulation of uPA at both the protein and mRNA levels in corneal epithelial cells. uPA may thus contribute to epithelial cell migration during corneal epithelial wound healing.

Animals↗

PubMed2003

Permissive effect of fibronectin on collagen gel contraction mediated by bovine trabecular meshwork cells.

PURPOSE: The effect of fibronectin on the contractility of trabecular meshwork (TM) cells was investigated. METHODS: The contractility of bovine TM cells was evaluated by culture of the cells in a collagen gel and measurement of the change in the diameter of the gel under various conditions. The formation of stress fibers and the localization of integrin alpha5 and beta1 chains (which together form a fibronectin receptor) in bovine TM cells were investigated by laser confocal microscopy of cells stained with phalloidin and antibodies to the integrin subunits. RESULTS: The addition of fibronectin to collagen gels containing bovine TM cells induced marked gel contraction in a time- and concentration-dependent manner. Cytochalasin D (an inhibitor of microfilament formation) and the peptide GRGDSP (Gly-Arg-Gly-Asp-Ser-Pro), a fibronectin receptor antagonist, each inhibited this effect of fibronectin, whereas nocodazole (an inhibitor of microtubule polymerization) and the control peptide GRGESP (Gly-Arg-Gly-Glu-Ser-Pro) did not. Furthermore, fibronectin induced the spreading of cells, the formation of actin stress fibers, and the expression of integrin alpha5 in the collagen gel-embedded TM cells. CONCLUSIONS: Fibronectin promotes collagen gel contraction mediated by bovine TM cells. Moreover, the formation of actin stress fibers and upregulation of integrin alpha5 appear to contribute to this permissive effect of fibronectin. The interaction of fibronectin with TM cells may thus be a determinant of the contractility of TM tissue.

Actins↗

PubMed2003

Effects of substance P and IGF-1 in corneal epithelial barrier function and wound healing in a rat model of neurotrophic keratopathy.

PURPOSE: To establish a rat model of neurotrophic keratopathy and to examine the effects of the combination of substance P (SP) and insulin-like growth factor (IGF)-1 on corneal epithelial barrier function and wound healing in this model. METHODS: Corneal denervation was achieved by thermocoagulation of the ophthalmic branch of the trigeminal nerve. A modified Schirmer test was performed without topical anesthesia. Corneal epithelial barrier function was assessed by measurement of fluorescein permeability with an anterior fluorophotometer. Epithelial wound healing was evaluated by measurement of the area of the defect at various times after removal of the entire epithelium. Eye drops containing both 1 mM SP and IGF-1 (1 micro g/mL) were administered six times daily. RESULTS: The Schirmer test result in eyes subjected to trigeminal denervation was lower than that in control eyes. The fluorescein permeability of the corneal epithelium of denervated eyes was increased relative to that of control eyes. Furthermore, trigeminal denervation induced a delay in corneal epithelial wound healing. Application of eye drops containing SP and IGF-1 to denervated corneas restored the fluorescein permeability of the corneal epithelium to control levels and abolished the delay in epithelial wound healing. CONCLUSIONS: A rat model of neurotrophic keratopathy, characterized by reduced tear secretion, loss of corneal sensation, impaired epithelial barrier function, and delayed epithelial wound healing, was established by trigeminal denervation. Treatment with both SP and IGF-1 improved corneal epithelial barrier function and stimulated corneal epithelial wound healing in this model.

Animals↗