Effects of the cytokines on the proliferation of and collagen synthesis by human cataract lens epithelial cells

Altered response of intestinal mucosal fibroblasts to profibrogenic cytokines in inflammatory bowel disease

BACKGROUND AND AIMS

Fibrosis is a major complication of inflammatory bowel disease (IBD), which may be mediated by the intestinal fibroblast. Our aim was to isolate and characterize mucosal fibroblasts from histologically normal intestine (control), ulcerative colitis (UC), inflamed Crohn's disease (CD), and fibrosed CD intestine.

METHODS

Fibroblasts were characterized by light and electron microscopy and immunohistochemistry. Fibroblast collagen secretion and proliferation were determined by 3H-proline and 3H-thymidine incorporation, and the effects of exposure to interleukin (IL)-1beta, basic fibroblast growth factor (bFGF), platelet-derived growth factor (PDGF), transforming growth factor (TGF)-beta1, insulin-like growth factor (IGF)-1, and macrophage colony stimulating factor (M-CSF) were determined.

RESULTS

No difference in doubling time was observed between the fibroblast populations from UC and CD intestine. All proliferated faster than fibroblasts from control intestine. Collagen secretion from IBD fibroblasts, independent of type, was increased compared with control fibroblasts and PDGF, bFGF, and TGF-beta1-induced collagen secretion from IBD fibroblasts.

CONCLUSIONS

These results suggest the presence of an activated subpopulation of fibroblasts in both UC and CD tissue irrespective of the presence of tissue fibrosis or disease type.

Prevention of posterior capsule opacification by intraoperative single-dose pharmacologic agents

PURPOSE

To determine whether an intraoperative single dose of dexamethasone, diclofenac, ethylenediaminetetraacetic acid (EDTA), a combination of EDTA and RGD peptide (arginine-glycin-aspartic acid sequence), or mitomycin-C (MMC) is a pharmacological means of preventing or reducing the development of posterior capsule opacification (PCO).

SETTING

Department of Ophthalmology, Celal Bayar University, School of Medicine, Manisa, and Department of Pathology, Dokur Eylül University, School of Medicine, Izmir, Turkey.

METHODS

Fifty-four rabbits were randomly divided into 6 groups. Dexamethasone (4 mg/cc), diclofenac (2.5 mg/cc), EDTA (8 mg/cc), a combination of EDTA and RGD peptide (2.5 mg/cc), or MMC (0.04 mg/cc) was given, 0.1 cc by hydrodissection and 0.9 cc into the capsular bag after phacoemulsification. The sixth group served as a control group. After 3 months, the PCO was graded clinically and the proliferation of lens epithelial cells (LECs) was evaluated histologically.

RESULTS

The drugs were significantly effective in preventing PCO compared with the control (P <.005). Dexamethasone had a weaker effect than the other drugs. In histological analysis, although monolayer LECs in the dexamethasone and diclofenac groups were observed, there was no proliferative activity on the posterior capsules in the EDTA, EDTA+RGD, and MMC groups in contrast to the multilayer cells in the control.

CONCLUSIONS

Intraoperative single-dose application of EDTA, EDTA+RGD peptide combination, and MMC significantly prevented the development of PCO in rabbit eyes. Diclofenac was less effective but also reduced PCO. Although dexamethasone did not prevent the proliferation of LECs, it decreased PCO clinically.

Lens epithelial cell outgrowth on 3 types of intraocular lenses

PURPOSE

To compare the outgrowth of lens epithelial cells (LECs) on 3 types of intraocular lenses (IOLs) to determine the influence of lens material and lens design (optic edge) on this phenomenon.

SETTING

Department of Ophthalmology, University of Vienna, Medical School, Vienna, Austria.

METHOD

Ninety eyes scheduled for cataract surgery were included in a prospective comparative study. A standardized surgical procedure was performed by 1 experienced surgeon. Patients received 1 of 3 types of posterior chamber IOLs of similar design with a 6.0 mm optic and poly(methyl methacrylate) haptic: AcrySof (Alcon), HydroView (Bausch & Lomb), or Sensar (Allergan). Each IOL type was implanted in 30 eyes. Postoperative biomicroscopic examinations were performed 1, 3, 7, 30, 90, and 180 days and 1 year after surgery. Lens epithelial cells in each quadrant of the anterior lens surface were subjectively graded. The product with the highest density and the number of quadrants with this density were used to measure LEC outgrowth.

RESULTS

Statistically significant differences (P <.05) were seen between the hydrophilic IOL and the 2 hydrophobic lenses from day 30 until the final examination. The HydroView lens had a higher number of LECs on its anterior surface than the AcrySof or Sensar IOL. There were no statistically significant differences between the 2 acrylic IOLs at any measurement.

CONCLUSION

The findings suggest that lens surface properties have a greater influence on LEC outgrowth than lens design (ie, sharp optic edge).

Downregulated Expression of Integrin α6 by Transforming Growth Factor-β1 on Lens Epithelial Cells in Vitro

Integrins represent the main cell surface receptors that mediate cell-matrix and cell-cell interactions. They play critical roles in adhesion, migration, morphogenesis, and the differentiation of several cell types. Previous studies have demonstrated that members of the fibroblast growth factor (FGF)-2, transforming growth factor (TGF)-beta(1), and insulin growth factor (IGF)-1 play important roles in lens biology. In particularly, TGF-beta(1) appears to play a key role in extracellular matrix production, cell proliferation, and cell differentiation of lens epithelial cells. In this study we investigated the effects of FGF-2, TGF-beta(1), and IGF-1 on the modulation of integrin receptors using lens epithelial cell lines (HLE B-3 and alphaTN-4) and lens explants. We found that the expression of integrin alpha6 is downregulated by TGF-beta(1), but is not responsive to FGF-2 or IGF-1. The promoter activity of the integrin alpha6 gene decreased upon TGF-beta(1) treatment in a transient transfection assay, and flow cytometric analysis demonstrated the reduced expression of integrin alpha6 by TGF-beta(1), whereas significant changes were not observed in the level of integrin alpha6 after the addition of FGF-2. These findings suggest that the reduced expression of integrin alpha6 caused by TGF-beta(1) might play a role in the activation of the cell cycle genes required during the fiber differentiation of the lens.

Smad translocation and growth suppression in lens epithelial cells by endogenous TGFbeta2 during wound repair

To determine whether endogenous TGFbeta affects lens epithelial cells during repair after an anterior capsule injury in mice, we studied translocation of Smad proteins, which carry the TGFbeta signal from cell surface receptors to promoters in nuclei. We immunolocalized Smads in murine lenses at intervals up to 8 weeks following capsular injury. Effects of injecting TGFbeta neutralizing antibodies on Smad4 location and cell proliferation were examined at 24 hr after injury. Finally, we examined whether exogenous TGFbeta2 induced Smad nuclear translocation in murine lenses in organ culture. Cell proliferation was quantitated by 5-bromo-2'-deoxyuridine (BrdU) labelling. In uninjured lenses, Smads were located in the cytoplasm. In injured lenses, nuclear localization of Smads was observed in cells next to the capsular break from 8 to 24 hr after the injury, and was observed peripheral to the break at 48 hr. Nuclear Smads then continued to be observed occasionally in a minority of cells. Injection of antibodies neutralizing TGFbeta2, but not TGFbeta1 or TGFbeta3, inhibited Smad4 nuclear translocation and resulted in the appearance of BrdU-positive anterior epithelial cells. With the lenses in culture, transient nuclear localization of Smads occurred between 3 and 24 hr in response to continuous exposure to TGFbeta2. No nuclear translocation was seen at 48 hr. Endogenous TGFbeta2 affects lens cells during wound repair after anterior capsule injury, inhibiting lens cell proliferation during the early phase. Nuclear translocation of Smads in lens epithelial cells is transient even with continuous exposure to TGFbeta2.

Transforming growth factor-beta isoform proteins in cell and matrix deposits on intraocular lenses

PURPOSE

To determine whether the cells that adhere to poly(methyl methacrylate) (PMMA) posterior chamber intraocular lenses (PC IOLs) implanted in human eyes produce transforming growth factor-beta (TGF-beta) isoforms and whether the acellular proteinaceous deposits on these IOLs contain TGF-beta.

SETTING

Department of Ophthalmology, Wakayama Medical College, Japan.

METHODS

Thirty-two PMMA PC IOLs explanted from Japanese patients were immunostained for TGF-beta1, -beta2, or -beta3, and observed under light microscopy.

RESULTS

Cell deposits were observed on 12 IOLs and proteinaceous deposits on 16. Components of the cell deposits were mainly of macrophage origin. The cell and matrix deposits tested positive for each isoform of TGF-beta.

CONCLUSION

The cells that adhered to implanted PMMA PC IOLs produced TGF-beta, and the extracellular matrix that accumulated on the surface of the IOLs contained TGF-beta. Transforming growth factor-beta from the cells on IOLs may influence the healing process of residual lens capsules after cataract surgery with IOL implantation.

Anterior capsule opacification: a histopathological study comparing different IOL styles

OBJECTIVE

To compare the degree of anterior capsule opacification (ACO) in human eyes obtained post-mortem containing various rigid and foldable posterior chamber intraocular lens (PC-IOL) designs.

DESIGN

Comparative autopsy tissue study with clinicopathologic correlations.

MATERIALS

Four hundred sixty human globes containing the following PC-IOL styles were analyzed: (1) one-piece polymethylmethacrylate (PMMA) optic-PMMA haptic (n = 50), (2) one-piece silicone-plate IOL, large hole (n = 40), (3) one-piece silicone-plate IOL, small hole (n = 67), (4) three-piece PMMA optic-PMMA/Prolene haptic (n = 51), (5) three-piece acrylic optic-PMMA haptic (n = 96), (6) three-piece silicone optic-PMMA haptic (n = 24), (7) three-piece silicone optic-polyimide haptic (n = 40), and (8) three-piece silicone optic-prolene haptic (n = 92).

TESTING

The globes were sectioned in the equatorial plane for gross examination and then processed through paraffin; sectioned, and stained with hematoxylin-eosin, periodic acid-Schiff, and Masson's trichrome stains; and examined by light microscopy.

MAIN OUTCOME MEASURES

Anterior capsule opacification was scored in each eye by grading the histologic sections from 0 to III, according to the amount (thickness) of proliferative tissue and cells measured in sagittal sections on the inner surface of the anterior capsule at the capsulorhexis margin.

RESULTS

The difference among the eight groups was significant (P < 0.0001). Mean ACO scores were highest with the large and small hole one-piece silicone-plate lenses (1.77 +/- 0.86 and 1.28 +/- 0.77, respectively). The lowest mean score was observed in the group of three-piece acrylic optic-PMMA haptics lenses (0.51 +/- 0.52).

CONCLUSIONS

Our results confirm previous clinical observations that the rate of ACO is relatively high with plate-haptic silicone IOLs. The lowest rate was noted with the three-piece acrylic optic-PMMA haptic IOL. The IOL design and IOL material are significant factors in the development of ACO.

Inhibition of rabbit keratocyte and human fetal lens epithelial cell proliferation by retrovirus-mediated transfer of antisense cyclin G1 and antisense MAT1 constructs

The aim of this study is to evaluate the potential of gene transfer of cell cycle control genes as treatment of corneal haze or secondary cataract formation. The guiding hypothesis is that strategic modulation of the cyclin G1 or MAT1 gene by retrovirus-mediated gene transfer will inhibit proliferation of rabbit keratocytes (RabK) and fetal human lens epithelial (FHLEpi) cells in vitro. RabK and FHLEpi cell cultures were transduced in triplicate with retroviral vectors bearing either a nuclear-targeted beta-galactosidase, an antisense cyclin G1 (aG1), an antisense MAT1 (aMAT1) construct, or the neo(r) gene. The presence of beta-galactosidase activity in the transduced cultures was detected by immunohistochemical X-Gal staining, while cyclin G1 and MAT1 protein expression levels were evaluated by Western analysis. Proliferation of RabKs and FHLEpi cells was analyzed by counting the number of cells in the aG1 and aMAT1 vector-transduced cultures over 5 days. The mean transduction efficiency was 34.4% (SD 1.41) for RabKs and 19.7% (SD 1.83) for FHLEpi cells. Downregulation of cyclin G1 and MAT1 protein expression was noted 24 hr after transduction of RabK cultures with the respective vectors. Cytostatic effects of the aG1 and aMAT1 vectors in both RabKs and FHLEpi cells were most pronounced on the fifth day (RabKs, p < 0.0007; FHEpi cells, p < 0.001). An increased incidence of apoptosis was identified in both aG1 and MAT1-transduced FHLEpi cells. Taken together, these data suggest the potential utility of developing aG1 and aMAT1 retroviral vectors in gene therapy protocols for corneal haze and secondary cataract formation.

Influence of intraocular lens material and design on postoperative intracapsular cellular reactivity

PURPOSE

To evaluate the influence of intraocular lens (IOL) material and design on the outcome of postoperative lens epithelial cell proliferation within the capsular bag after cataract surgery.

METHODS

A total of 5,079 human globes containing rigid and foldable posterior chamber IOL styles commonly implanted in the United States (n = 8) were analyzed in this study. Each globe, fixated in 10% formalin, was sectioned at the equator and analyzed using the Miyake-Apple posterior technique. The study consisted of 3 parts: First, to evaluate posterior capsule opacification (PCO); the Nd:YAG laser posterior capsulotomy rate (%) was documented and plotted on a monthly basis, creating a computerized trend line for each IOL style. Second, to evaluate anterior capsule opacification (ACO); 460 globes were processed for histologic examination. Anterior capsule fibrosis was scored from 0 to III, according to the thickness of proliferative tissue/cells on the inner surface of the anterior capsule at the capsulorhexis margin. Third, interlenticular opacification (ILO) was studied by analysis of 3 pairs of acrylic piggyback lenses that had been explanted because of opacification between their optics. Each IOL pair was processed for histologic examination, and scanning electron microscopy was performed on 1 of the lenses.

RESULTS

In the first study, relatively higher Nd:YAG laser posterior capsulotomy rates (19.1% to 32.8%) were noted with the 4 oldest IOL designs in this study (2 foldable lenses, 1 3-piece polymethyl methacrylate [PMMA] design, and 1 single-piece all-PMMA design). Four modern lenses, 1 acrylic lens, and 3 silicone foldable IOL designs had Nd:YAG rates ranging from 1.3% to 14.6% (P < .0001). In the second study, mean ACO scores were highest with silicone-plate lenses (1.77 +/- 0.86 and 1.28 +/- 0.77). The lowest mean score was observed with the acrylic lens (0.51 +/- 0.52; P < .0001). In study 3, the analyses of the 3 pairs of explanted acrylic piggyback lenses showed that the opacification between them (ILO) may have different forms.

CONCLUSIONS

Control of postoperative intracapsular cellular proliferation is important in avoiding 3 significant clinical complications. Postoperative lens epithelial cell proliferation is involved in the pathogenesis of PCO, ACO, and ILO, the latter being a newly described form of opacification within the capsular bag related to piggyback IOL implantation. IOL material and design are important factors influencing the outcome of these complications.

Concentration dependent effects of hydrogen peroxide on lens epithelial cells

AIMS

To evaluate the effects of hydrogen peroxide exposure on the survival and proliferation of cultured lens epithelial cells.

METHODS

TOTL-86 cells, a line of rabbit lens epithelial cells, were used. The survival and proliferation of TOTL-86 cells were quantified by a rapid colorimetric assay (MTT assay). To determine the effects of hydrogen peroxide, TOTL-86 cells were exposed to different concentrations of hydrogen peroxide. To determine the effect of cell numbers on the survival and proliferation of TOTL-86 cells at a fixed concentration of hydrogen peroxide, different numbers of cells were plated and exposed to hydrogen peroxide. To determine whether there is a synergistic effect between hydrogen peroxide and EGF, bFGF, PDGF-AA, and insulin, TOTL-86 cells were exposed to hydrogen peroxide combined with one of these growth factors.

RESULTS

High levels (1 mM) of hydrogen peroxide killed TOTL-86 cells and sublethal levels (100 microM) suppressed their proliferation. From 1 nM to 1 microM of hydrogen peroxide, there was a dose dependent increase in the cell numbers. The initial seeded cell number dramatically affected the response to hydrogen peroxide. Although growth factors showed no synergistic effects with hydrogen peroxide on proliferation, both EGF and insulin, but not bFGF or PDGF, rescued TOTL-86 cells from the sublethal effect.

CONCLUSION

Hydrogen peroxide in cooperation with some growth factors plays an important role in the proliferation of lens epithelial cell.

High levels of plasma C-reactive protein and future risk of age-related cataract

PURPOSE

Chronic intraocular inflammation, with or without systemic inflammation, is associated with increased risk of cataract. Whether systemic inflammation alone is associated with cataract is unknown. This study examined the association between plasma C-reactive protein (CRP), a marker of systemic inflammation, and risk of cataract.

METHODS

In the Physicians' Health Study, we recently analyzed plasma CRP levels in baseline blood specimens from 543 men who later developed cardiovascular disease, and 543 who did not. These data provided a cost-efficient means to explore whether baseline plasma CRP is associated with future risk of age-related cataract. After excluding 252 men with prior diagnosis of cataract or missing data, we followed the remaining 834 men defined by baseline CRP level for 11 years for incident cataract. We used proportional hazards regression models, stratified by cardiovascular disease status.

RESULTS

Baseline CRP was significantly higher among men who later developed cataract than levels among those who remained free of cataract, P = 0.02 (median 1.53 versus 1.23 mg/L). In a multivariable model adjusted for cardiovascular disease, randomized aspirin and beta carotene assignments, age, diabetes, cigarette smoking, alcohol consumption, body mass index, exercise, and parental history of myocardial infarction, the levels of CRP remained significantly associated with development of cataract (P = 0.001); but the association was less significant in a model using log CRP levels (P = 0.038). In exploratory analyses of a threshold effect, the excess risk was significant only among men with levels at or above the 97.5th centile (6.17 mg/L); compared to those with lower levels, the relative risk in these men was 3.00 (95% confidence interval, 1.53 to 5.91; P = 0.002). Relative risks associated with CRP levels at or above versus below the 85th, 90th, and 95th percentiles were not significant (relative risks 1.29, 1.50, and 1.77, respectively).

CONCLUSIONS

Overall, our results suggest that elevated levels of CRP are associated with future risk of cataract in these apparently healthy men. This early report raises the possibility that systemic inflammation may play a role in the pathogenesis of age-related cataract.

Posterior capsule opacification. Part 1: Experimental investigations

Posterior capsule opacification (PCO) is the most frequent complication associated with decreased vision after cataract surgery. Previous methods of preventing PCO have not proven to be practical, effective, and safe for routine clinical procedure, but some novel concepts and methods have recently been developed. This 2-part review looks at clinical and experimental investigations of PCO, focusing on developments since 1992. Clinical aspects will be presented in a later issue. This paper addresses (1) in vitro models for PCO research; (2) pathophysiology and molecular biology of lens epithelial cells (LECs); (3) prevention of PCO. Of special interest are methods of culturing human LECs obtained by capsulotomy during cataract surgery, including those obtained with an intact capsular bag, to provide an in vitro model for investigating the pathophysiology of LECs; the effect of a sharp bend in the lens capsule that induces contact inhibition of migrating LECs; more specific inhibition of migrating LECs using an immunotoxin, b-FGF-saporin, or EDTA and RGD-peptides.

Anterior capsule contraction and intraocular lens dislocation after implant surgery in eyes with retinitis pigmentosa

OBJECTIVE

The purpose of the study was to investigate the extent of anterior capsule contraction, intraocular lens (IOL) decentration, and tilt after implant surgery in eyes with retinitis pigmentosa (RP).

DESIGN

A case-control study.

PARTICIPANTS

Forty-seven eyes from 47 patients with typical RP and 47 control eyes from 47 age-matched healthy patients were studied.

INTERVENTION

Phacoemulsification surgery with polymethylmethacrylate IOL implantation with continuous curvilinear capsulorrhexis was performed.

MAIN OUTCOME MEASURES

The area of the anterior capsule opening obtained with capsulorrhexis and the amount of the decentration and tilt of the IOL were measured using a Scheimpflug photography system at 1 week and 1, 3, 6, 9, and 12 months after surgery.

RESULTS

The mean area in the RP group was found to be significantly smaller than that in the control group at 1 month after surgery and later (P < 0.0001). The percent area reduction in the RP group at 6 months was 45.2 +/- 25.8% and 4.6 +/- 13.5% in the control group. Both the decentration length and tilt angle were also greater in the RP group than in the control group. Fourteen (29.8%) of the 47 RP eyes had undergone a neodymium:YAG (Nd:YAG) laser anterior capsulotomy at 12 months after surgery, whereas none of the control eyes had undergone an Nd:YAG.

CONCLUSIONS

Anterior capsule contraction in the RP eyes was more extensive than in the control eyes, leading to a high Nd:YAG laser anterior capsulotomy rate. Both lens decentration and tilt also were greater in the RP eyes than in the control eyes.

Phacoemulsification versus extracapsular cataract extraction: a comparative study of cell survival and growth on the human capsular bag in vitro

AIMS/BACKGROUND

Phacoemulsification is rapidly replacing conventional extracapsular cataract extraction (ECCE) as the method of choice for cataract surgery in the Western world. However, posterior capsule opacification (PCO) still remains the major postoperative complication, affecting 20-50% of patients, and results from persistent cell growth of epithelial cells remaining after surgery. This study aimed to compare cell survival and growth on capsular bags following ECCE and phacoemulsification surgery using an established human capsular bag culture system.

METHODS

Sham ECCE and phacoemulsification cataract operations were performed on pairs of human donor eyes. Capsular bags were dissected free, pinned flat on a petri dish, and incubated with Eagle's minimum essential medium (EMEM) alone or EMEM supplemented with 10% fetal calf serum (FCS). Ongoing observations were made using phase contrast microscopy.

RESULTS

Cell growth was observed across the posterior capsule of all preparations studied. It was found that there was no significant difference in the rate of cell growth on the posterior capsule with the two extraction methods, such that 50% confluency was achieved in 7.0 (SD 1.8) (n = 7) days for ECCE and 7.43 (2.1) (n = 7) days for phacoemulsification surgery. The physical changes to the capsule as a result of cell growth, such as wrinkling and capsular tensioning, were also seen in both groups.

CONCLUSIONS

Cell survival and growth is dependent on the donor, rather than the surgical technique performed. There is no significant difference between phacoemulsification and ECCE surgery on the rate and nature of cell growth on the posterior capsule in vitro.

Diclofenac sodium and cyclosporin A inhibit human lens epithelial cell proliferation in culture

PURPOSE

To investigate the effect of diclofenac sodium salt and cyclosporin A (CsA) on human lens epithelial cell (HLEC) growth in culture.

METHODS

Cultures of HLEC were obtained from anterior capsules from extracapsular cataract surgery. Third-passage cells were seeded in 96-well plates in 0.1 ml culture medium. Cytotoxicity was estimated by the tetrazolium test in confluent monolayers after 24 h exposure to a wide range of concentrations of diclofenac and CsA. The effect of subcytotoxic concentrations of diclofenac and CsA on HLEC proliferation in subconfluent cultures was evaluated after 24 and 72 h of exposure. To investigate the relationship between PGE2 synthesis and the inhibitory effect of these drugs, after 24 h of exposure to diclofenac and CsA the production of PGE2 was measured by radioimmunoassay. We also tested the effect of exogenous PGE2 addition to diclofenac 72-h-treated cultures.

RESULTS

Diclofenac and CsA (at concentrations > or = 65 microM and > or = 2.5 microM, respectively) inhibited the proliferation of subconfluent cultures of HLEC in a dose-dependent fashion. Diclofenac inhibits PGE2 synthesis, while CsA at high doses stimulates PGE2 synthesis of cultured HLEC. Exogenous PGE2 addition reversed in part the inhibitory effect of diclofenac.

CONCLUSIONS

Diclofenac and CsA at appropriate doses are effective in inhibiting cultured HLEC proliferation. This could be of interest to prevent posterior capsule opacification. Further in vivo experimental studies seem worthwhile.