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Purpose: Disruption of proteostasis is a key event in many neurodegenerative diseases. Heat shock proteins (HSPs) participate in multiple functions associated with intracellular transport and proteostasis. We evaluated the effect of augmented HSP70 expression in mutant photoreceptors of mouse retinal degeneration models to test the hypothesis that failure to sustain HSP70 expression contributes to photoreceptor cell death., Methods: We examined HSP70 expression in retinas of wild-type and mutant mice by RNA and protein analysis. A transgenic mouse line, TgCrx-Hspa1a-Flag, was generated to express FLAG-tagged full-length HSP70 protein under control of a 2.3 kb mouse Crx promoter. This line was crossed to three distinct retinal degeneration mouse models. Retinal structure and function were evaluated by histology, immunohistochemistry, and electroretinography., Results: In seven different mouse models of retinal degeneration, we detected transient elevation of endogenous HSP70 expression at early stages, followed by a dramatic reduction as cell death ensues, suggesting an initial adaptive response to cellular stress. Augmented expression of HSP70 in RHOT17M mice, in which mutant rhodopsin is misfolded, marginally improved photoreceptor survival, whereas elevated HSP70 led to more severe retinal degeneration in rd10 mutants that produce a partially functional PDE6B. In Rpgrip1-/- mice that display a ciliary defect, higher HSP70 had no impact on photoreceptor survival or function., Conclusions: HSP70 overexpression has divergent effects in photoreceptors determined, at least in part, by the nature of the mutant protein each model carries. Additional investigations on HSP pathways and associated chaperone networks in photoreceptors are needed before designing therapeutic strategies targeting proteostasis.

Purpose: To examine the associations of the earlier reported glaucoma-related genes to the regional circumpapillary retinal nerve fiber layer thicknesses (cpRNFLTs) and corresponding visual field defects., Methods: We studied 756 patients with primary open-angle glaucoma (POAG) and 3094 normal controls. Each participant was genotyped for nine single nucleotide polymorphisms (SNPs) of four glaucoma-susceptible genes: the CDKN2B(AS1), TMCO1, CAV1/CAV2, and SIX1/SIX6 genes. For the SNPs that were significantly associated with the POAG case-control analyses, the associations of SNP genotypes with the cpRNFLTs of 12 sectors were also analyzed, and then finer assessments were performed using 768 points of the cpRNFLT and corresponding visual field defect sensitivities using case-only subjects., Results: We confirmed that there was a significant association of the CDKN2B(AS1) gene to POAG. For the suggested region-specific associations of these genes with the 12-sectored cpRNFLT, a 768-point cpRNFLT examination showed that rs4977756 near CDKN2B had significant signal peaks in the temporal region at 330° to 360° and 0° to 30° (maximum β = 2.92, P = 2.9 × 10-5 at 351.1° and maximum β = 3.97, P = 2.2 × 10-4 at 23.4°, respectively). These region-specific signals were validated by the corresponding visual field defect patterns of the paracentral/lower hemifield (P < 0.05)., Conclusions: Genetic association analyses using the cpRNFLT with 768 points suggest that the CDKN2B gene was associated with paracentral/lower hemifield scotomas. Our regional association analyses on cpRNFLT allow detailed characterization of glaucoma-related genes and should be a new target for genomic studies for glaucoma endophenotypes.

Purpose: Cell death in neurodegeneration occurs at the convergence of diverse metabolic pathways. In the retina, a common underlying mechanism involves mitochondrial dysfunction since photoreceptor homeostasis and survival are highly susceptible to altered aerobic energy metabolism. We sought to develop an assay to directly measure oxygen consumption in intact retina with the goal of identifying alterations in respiration during photoreceptor dysfunction and degeneration., Methods: Circular punches of freshly isolated mouse retina, adjacent to the optic nerve head, were used in the microplate-based Seahorse Extracellular Flux Analyzer to measure oxygen consumption. Tissue integrity was evaluated by propidium iodide staining and live imaging. Different substrates were tested for mitochondrial respiration. Basal and maximal respiration were expressed as oxygen consumption rate (OCR) and respectively measured in Ames' medium before and after the addition of mitochondrial uncoupler, BAM15., Results: We show that glucose is an essential substrate for retinal mitochondria. At baseline, mitochondria respiration in the intact wild-type retina was close to maximal, with limited reserve capacity. Similar OCR and limited mitochondrial reserve capacity was also observed in cone-only Nrl-/- retina. However, the retina of Pde6brd1/rd1, Cep290rd16/rd16 and Rpgrip1-/- mice, all with dysfunctional or no photoreceptors, had reduced OCR and higher mitochondrial reserve capacity., Conclusions: We have optimized a method to directly measure oxygen consumption in acutely isolated, ex vivo mouse retina and demonstrate that photoreceptors have low mitochondrial reserve capacity. Our data provide a plausible explanation for the high vulnerability of photoreceptors to altered energy homeostasis caused by mutations or metabolic challenges.

Purpose: To examine bacterial virulence factors in Pseudomonas aeruginosa isolates from contact lens (CL) wearers and non-CL wearers with P. aeruginosa keratitis, and to investigate relationships between virulence factors and clinical features of keratitis., Methods: The study involved 25 subjects including 18 CL and 7 non-CL-related P. aeruginosa keratitis patients. Slit-lamp photographs of all subjects were captured, and the focus occupancy ratio (FOR) was defined as the total focus area/entire cornea area, using image processing software. Twenty-five clinical P. aeruginosa isolates from keratitis were assessed for protease production, elastase production, biofilm formation, bacterial swimming and swarming motility, cell surface hydrophobicity, and genes encoding the type III secretion system (TTSS) effectors (ExoU and ExoS)., Results: Ring abscess was found in 9 of 18 CL-related P. aeruginosa keratitis cases (CL[+] ring[+] group) but not in another 9 cases (CL[+] ring[-] group). Expression or prevalence of virulence factors in P. aeruginosa isolates from the CL(+) ring(+) group, CL(+) ring(-) group, and CL(-) group were compared. The FOR for CL(+) ring(+) or CL(-) was higher than for CL(+) ring(-) (P < 0.05 and P < 0.01, respectively). The rate of positive swimming motility for CL(+) ring(+) or CL(-) was higher than for CL(+) ring(-) (P < 0.05), whereas the rate of positive swarming motility for CL(+) ring(+) was higher than for CL(+) ring(-) or CL(-) (P < 0.05). Prevalence of an exoS+/exoU-genotype for CL(+) ring(+) or CL(-) was higher than for CL(+) ring(-) (P < 0.05). In the CL-related group, expression of elastase and swarming motility significantly correlated with FOR., Conclusions: Swimming motility, swarming motility, and TTSS ExoS could play a major role in the determination of clinical features of P. aeruginosa keratitis.

Purpose: To correlate a genetic risk score based on age-related macular degeneration (AMD) susceptibility genes with the risk of AMD in the second eye., Methods: This is a retrospective, open cohort study consisting of 891 unilateral AMD patients, who were followed for at least 12 months and recruited from three institutes. DNAs were genotyped using Illumina OmniExpress, HumanOmni2.5-8, and/or HumanExome. Survival analyses and Cox proportional hazard models were used to examine the association between 11 AMD susceptibility genes and the duration until second-eye involvement in 499 samples from Kyoto University, which were replicated in two other cohorts. Genetic risk score (GRS) was also evaluated., Results: The ARMS2 rs10490924 recessive model (hazard ratio [HR]meta = 2.04; Pmeta = 3.4 × 10⁻³) and CFH rs800292 additive model (HRmeta = 1.77; Pmeta = 0.013) revealed significant associations with second-eye involvement. The dominant model of TNFRSF10A rs13278062, VEGFA rs943080, and CFI rs4698775 showed consistent effects across three datasets (I² = 0%; HRmeta = 1.46, 1.30, 1.51, respectively). The GRS using these five single nucleotide polymorphisms (SNPs) was also significantly associated (HRmeta [per score] = 2.42; P = 2.2 × 10⁻⁵; I² = 0%). After 10 years from the first visit, the patients within the top 10% by GRS showed a 51% hazard rate, in contrast to 2.3% among patients within the lowest 10% by GRS., Conclusions: We demonstrated that the GRS using ARMS2, CFH, TNFRSF10A, VEGFA, and CFI was significantly associated with second-eye involvement. Genetic risk has high predictive ability for second-eye involvement of AMD.

Purpose: We investigated the association between refractive error in a Japanese population and myopia-related genes identified in two recent large-scale genome-wide association studies., Methods: Single-nucleotide polymorphisms (SNPs) in 51 genes that were reported by the Consortium for Refractive Error and Myopia and/or the 23andMe database were genotyped in 3712 healthy Japanese volunteers from the Nagahama Study using HumanHap610K Quad, HumanOmni2.5M, and/or HumanExome Arrays. To evaluate the association between refractive error and recently identified myopia-related genes, we used three approaches to perform quantitative trait locus analyses of mean refractive error in both eyes of the participants: per-SNP, gene-based top-SNP, and gene-based all-SNP analyses. Association plots of successfully replicated genes also were investigated., Results: In our per-SNP analysis, eight myopia gene associations were replicated successfully: GJD2, RASGRF1, BICC1, KCNQ5, CD55, CYP26A1, LRRC4C, and B4GALNT2.Seven additional gene associations were replicated in our gene-based analyses: GRIA4, BMP2, QKI, BMP4, SFRP1, SH3GL2, and EHBP1L1. The signal strength of the reported SNPs and their tagging SNPs increased after considering different linkage disequilibrium patterns across ethnicities. Although two previous studies suggested strong associations between PRSS56, LAMA2, TOX, and RDH5 and myopia, we could not replicate these results., Conclusions: Our results confirmed the significance of the myopia-related genes reported previously and suggested that gene-based replication analyses are more effective than per-SNP analyses. Our comparison with two previous studies suggested that BMP3 SNPs cause myopia primarily in Caucasian populations, while they may exhibit protective effects in Asian populations., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Purpose: Retinitis pigmentosa (RP), a major cause of blindness in developed countries, has multiple causative genes; its prevalence differs by ethnicity. Usher syndrome is the most common form of syndromic RP and is accompanied by hearing impairment. Although molecular diagnosis is challenging, recent technological advances such as targeted high-throughput resequencing are efficient screening tools., Methods: We performed comprehensive molecular testing in 329 Japanese RP and Usher syndrome patients by using a custom capture panel that covered the coding exons and exon/intron boundaries of all 193 known inherited eye disease genes combined with Illumina HiSequation 2500. Candidate variants were screened using systematic data analyses, and their potential pathogenicity was assessed according to the frequency of the variants in normal populations, in silico prediction tools, and compatibility with known phenotypes or inheritance patterns., Results: Molecular diagnoses were made in 115/317 RP patients (36.3%) and 6/12 Usher syndrome patients (50%). We identified 104 distinct mutations, including 66 novel mutations. EYS, USH2A, and RHO were common causative genes. In particular, mutations in EYS accounted for 15.0% of the autosomal recessive/simplex RP patients or 10.7% of the entire RP cohort. Among the 189 previously reported mutations detected in the current study, 55 (29.1%) were found commonly in Japanese or other public databases and were excluded from molecular diagnoses., Conclusions: By screening a large cohort of patients, this study catalogued the genetic variations involved in RP and Usher syndrome in a Japanese population and highlighted the different distribution of causative genes among populations., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Purpose: To evaluate the clinical utility of wide-field fundus autofluorescence (FAF) in patients with cone dystrophy and cone-rod dystrophy., Methods: Sixteen patients with cone dystrophy (CD) and 41 patients with cone-rod dystrophy (CRD) were recruited at one institution. The right eye of each patient was included for analysis. We obtained wide-field FAF images using a ultra-widefield retinal imaging device and measured the area of abnormal FAF. The association between the area of abnormal FAF and the results of visual acuity measurements, kinetic perimetry, and electroretinography (ERG) were investigated., Results: The mean age of the participants was 51.4 ± 17.4 years, and the mean logarithm of the minimum angle of resolution was 1.00 ± 0.57. The area of abnormal FAF correlated with the scotoma measured by the Goldman perimetry I/4e isopter (ρ = 0.79, P < 0.001). The area also correlated with amplitudes of the rod ERG (ρ = -0.63, P < 0.001), combined ERG a-wave (ρ = -0.72, P < 0.001), combined ERG b-wave (ρ = -0.66, P < 0.001), cone ERG (ρ = -0.44, P = 0.001), and flicker ERG (ρ = -0.47, P < 0.001)., Conclusions: The extent of abnormal FAF reflects the severity of functional impairment in patients with cone-dominant retinal dystrophies. Fundus autofluorescence measurements are useful for predicting retinal function in these patients., (Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.)

Purpose: Pseudomonas aeruginosa is a leading pathogen of blinding keratitis worldwide. In this study, the role of the serine protease in the pathogenesis of P. aeruginosa keratitis in the mouse cornea was investigated by comparing the parent and rescue strains., Methods: Cornea of C57BL/6 mice were infected with P. aeruginosa strain PAO1, serine protease (MucD protease or PA3535) mutants (ΔmucD or ΔPA3535), or a complemented strain. Corneal virulence was evaluated by determining clinical scores and bacterial enumeration. A myeloperoxidase assay was performed to determine the number of polymorphonuclear (PMN) cells infiltrating the cornea. An ELISA was used to quantify inflammatory cytokines and chemokines in the cornea., Results: The clinical score and bacterial numbers in eyes infected with ΔmucD were significantly lower than in those infected with PAO1, ΔPA3535, or the MucD rescue strain after 48 hours (P < 0.001). A larger number of infiltrating PMN cells was observed in eyes infected with ΔmucD at 12 and 24 hours, compared with eyes infected with PAO1. IL-1β, KC, and MIP2 levels were higher in eyes infected with ΔmucD than in those infected with PAO1 after 12 hours., Conclusions: The MucD protease suppressed IL-1β, KC, and MIP2 during the early stages of the infection and inhibited neutrophil recruitment in the cornea. Therefore, the MucD protease contributes significantly to the pathogenesis of keratitis. MucD protease plays a critical role in the establishment of Pseudomonas aeruginosa keratitis by facilitating evasion of the immune response.

Purpose: We investigated the association of genetic variations, which were identified recently in a large-scale genome-wide association study (GWAS) to confer risk of refractive error and common myopia in Caucasians, with high myopia in Japanese subjects., Methods: The 5 single-nucleotide polymorphisms (SNPs) from the 5 genes TOX, RDH5, ZIC2, RASGRF1, and SHISA6, were genotyped in 1339 unrelated highly myopic Japanese patients and 3248 healthy Japanese participants in the Nagahama Study. In addition, genotypes were compared between high myopia patients without choroidal neovascularization (CNV) and patients with myopic CNV., Results: Significant associations between rs8000973 near ZIC2 (P = 7.16 × 10(-7)), rs4778879 in RASGRF1 (P = 3.40 × 10(-7)), and rs2969180 in SHISA6 (P = 0.033) and high myopia were observed. Odds ratios (95% confidence intervals) were 1.33 (1.19-1.49), 0.78 (0.71-0.86), and 1.11 (1.01-1.22) for the rs8000973 C allele, rs4778879 A allele, and rs2969180 G allele, respectively. The effect of the rs2969180 allele G contrasted with that observed in the original report, whereas the effect of the other 2 SNPs agreed. Further analysis using controls with -1.0 diopter (D) ≤ spherical equivalent ≤ +1.0 D showed a significant association between ZIC2 and RASGRF1, but not SHISA6. Among the patients with high myopia, 516 had myopic CNV in either eye, while 823 patients did not have myopic CNV in eyes. No evaluated genes showed a significant association with the development of myopic CNV., Conclusions: ZIC2 and RASGRF1 are susceptibility genes, not only for common myopia, but also for high myopia.

Purpose: To determine whether genetic variants in the lipid-associated genes are related to the risk of developing polypoidal choroidal vasculopathy (PCV) in a Japanese population., Methods: Five hundred eighty-one patients with PCV and 793 controls were enrolled in the study. Association analysis of allele and genotype frequencies was performed for the following single-nucleotide polymorphisms (SNPs) that are associated with high-density lipoprotein cholesterol levels in blood: rs493258 at the hepatic lipase gene (LIPC), rs3764261 at the cholesteryl ester transfer protein gene (CETP), and rs12678919 at the lipoprotein lipase gene (LPL). A further model adjusting for age-related maculopathy susceptibility 2 (ARMS2) A69S, complement factor H (CFH) I62V, age, sex, and smoking status was used to confirm the independent association of these SNPs with other covariates., Results: CETP rs3764261 was significantly associated with the development of PCV; the frequency of the minor allele A was higher in the PCV cases (24.0%) than in the control subjects (18.5%) (P = 0.0025; odds ratio [OR], 1.41; 95% confidence interval, 1.13-1.75). Furthermore, we found an independent association of CETP variants with age, sex, smoking status, and genetic background of ARMS2 A69S, CFH I62V, LIPC rs493258, and LPL rs12678919 (P = 0.0013; OR, 1.50). LIPC rs493258 and LPL rs12678919 did not show significant associations with the development of PCV (P > 0.05)., Conclusion: CETP variants are associated a risk of developing PCV among the Japanese population.

Purpose: To determine whether genetic variants in the complement component 2 and factor B gene (C2/CFB) locus are associated with the risk for typical age-related macular degeneration (AMD) or polypoidal choroidal vasculopathy (PCV) in a Japanese population., Methods: Four single nucleotide polymorphisms (SNPs) were genotyped across the C2/CFB locus of patients with typical AMD (n = 455) or PCV (n = 581) and of 865 controls. Differences in the observed genotypic distribution between the case and control groups were tested by logistic regression analysis for age and sex adjustments. Significant associations were confirmed using a second control group of 336 cataract patients. A further model adjusting for age-related maculopathy susceptibility 2 (ARMS2) A69S, complement factor H (CFH) I62V, age, sex and smoking status was performed, to confirm their independent association from other covariates., Results: C2 rs547154 and CFB rs541862 were significantly associated with typical AMD and PCV in this Japanese sample (P < 0.05). These two SNPs were also significantly associated with typical AMD and PCV in evaluation of the second control cohort (P < 0.05). Furthermore, an independent association of C2/CFB variants was found for both typical AMD and PCV with age, sex, smoking, and genetic background of ARMS2 A69S and CFH I62V (vs. typical AMD: P = 0.0073, odds ratio [OR] = 0.47; vs. PCV: P = 0.0083, OR = 0.53)., Conclusions: C2/CFB variants play a protective role in the risk of developing neovascular AMD and PCV in the Japanese.

Purpose: To investigate whether the major genetic and environmental risk factors of age-related macular degeneration (AMD)-CFH Y402H and LOC387715 A69S and cigarette smoking-are also associated with polypoidal choroidal vasculopathy (PCV) and whether the associations of CFH Y402H and LOC387715 A69S with PCV are modified by smoking., Methods: Three hundred seventy-five Japanese patients with PCV and 847 Japanese who served as population-based control subjects, all ≥55 years of age, were studied. CFH Y402H (rs1061170) and LOC387715 A69S (rs10490924) were genotyped with a single-nucleotide polymorphism (SNP) assay. An unconditional logistic regression model was used to analyze the association between age, sex, smoking status, CFH Y402H, LOC387715 A69S, and PCV. The synergy index (SI) was measured to assess gene-smoking and gene-gene interaction as a departure from additivity., Results: CFH Y402H, LOC3387715 A69S, and cigarette smoking status were all significantly associated with PCV; for CFH Y402H, the adjusted odds ratio (OR) for the number of copies of the allele was 1.63 (95% confidence interval [CI], 1.12-2.36; P < 0.05); for LOC387715 A69S, the adjusted OR was 2.26 (95% CI, 1.83-2.78; P < 0.0001); and for smoking status (ever versus never smoked), the adjusted OR was 1.45 (95% CI, 1.00-2.10; P < 0.05). The joint effect of CFH Y402H and smoking was significantly greater than the additive scale, with an SI of 2.41 (95% CI, 1.14-5.10)., Conclusions: CFH Y402H and LOC387715 A69S are both significantly associated with PCV. Cigarette smoking is an environmental risk factor for PCV. The findings suggest interactions between CFH 402H and cigarette smoking in PCV.

Purpose: To seek an association in Japanese individuals between the CFH polymorphisms Y402H and I62V and the ARMS2 polymorphism A69S and age-related macular degeneration (AMD) or its three subtypes: typical (t)AMD, polypoidal choroidal vasculopathy (PCV), and retinal angiomatous proliferation (RAP)., Methods: The three polymorphisms were genotyped in a case-control study of 1351 control subjects and 962 patients with AMD., Results: The three polymorphisms correlated with AMD (Y402H, P = 1.54 × 10(-6); I62V, P =1.94 × 10(-29); and A69S, P = 9.56 × 10(-43)). The I62V and A69S polymorphisms were associated with all three subtypes: tAMD (P = 3.74 × 10(-18) and 1.37 × 10(-35), respectively), PCV (P = 3.18 × 10(-19) and 3.96 × 10(-18), respectively), and RAP (P = 0.034 and 2.49 × 10(-18), respectively). Y402H was associated with tAMD (P = 3.00 × 10(-5)) and with PCV (P = 9.73 × 10(-5)), but no association was found with RAP, possibly because of the small sample size and the rare minor allele. The risk allele contribution of A69S was stronger for RAP than for tAMD or PCV and was stronger for tAMD than for PCV., Conclusions: CFH Y402H is associated with AMD, tAMD, and PCV, whereas I62V is associated with all three subtypes. ARMS2 A69S has a strong association with all three subtypes, with the association being strongest for RAP and weakest for PCV. PCV and RAP may thus be subtypes of AMD that are genetically distinct from tAMD.

Purpose: The collagen type I alpha 1 (COL1A1) gene was recently reported to be associated with high myopia in the Japanese population. To validate this positive association, the tag single-nucleotide polymorphism (tSNP) approach was used., Methods: Eight tSNPs, including rs2075555 and rs2269336 (previously reported to be high myopia-susceptible SNPs in the Japanese), were selected to tag the linkage disequilibrium blocks harboring the COL1A1. These tSNPs were genotyped by using an SNP assay. A total of 427 unrelated Japanese cases with high myopia (axial length, >or=26.50 mm in both eyes; the refraction of the 644 phakic eyes ranged from -5.0 to -36.0 D, with a mean +/- SD of -13.61+/-4.20 D) and 420 Japanese control subjects were recruited. Genotype and allele distributions were compared between the cases and controls by using the chi(2) test, with multiple testing corrections performed by the permutation test., Results: There was no association noted between high myopia and rs2075555 (P=0.47, P(c)>0.99) and rs2269336 (P=0.40, P(c)>0.99). Meta-analysis of a previous Japanese study and new data obtained in a fixed-effect model indicated a mild significant association of high myopia with rs2075555 (odds ratio [OR], 1.19; 95% confidence interval [CI], 1.03-1.38, P=0.022) and rs2269336 (OR, 1.18; 95% CI, 1.02-1.36, P=0.026). No significant associations were seen with further tSNPs tests., Conclusions: This study did not replicate the previously reported positive association between COL1A1 and high myopia in the Japanese population, and thus the genetic risk associated with this gene, if any, is weaker than originally reported.

Purpose: This report presents a novel model for studies of extracellular matrix (ECM) in posterior capsular opacification (PCO) in vitro. Lens epithelial cells (LEC) were cultured with an intraocular lens (IOL) on a surface of type IV collagen in an evaluation of the importance of the ECM-cell interaction in formation of PCO. Abnormal migration, proliferation, and expression of proteins associated with the epithelial-to-mesenchymal transition (EMT) that characterizes PCO were observed in the presence and absence of the matricellular protein SPARC (secreted protein, acidic and rich in cysteine), which regulates matrix-cell interactions., Methods: The model for PCO in vitro consisted of an IOL placed on a membrane coated with collagen IV, a major constituent of the lens capsule. LECs from the lenses of wild-type (WT) and SPARC-null (SP-null) mice were cultured in the presence or absence of 10 ng/mL TGF-beta2 and 20 mug/mL recombinant human SPARC (rhSP) for up to 6 days. The migration of LECs was quantified. Labeling with BrdU and the measurement of DNA synthesis were assays for cell proliferation. Expression of the EMT markers, collagen type I, fibronectin, and alpha-smooth muscle actin were assessed using immunocytochemistry or Western immunoblots., Results: LEC migration, proliferation, and the synthesis of EMT markers were enhanced in SP-null compared with WT LECs. TGF-beta2 inhibited the migration and proliferation of both WT and SP-null LECs in the presence of rhSP. TGF-beta2 increased the production of collagen type I, fibronectin, and alpha-SMA. The responses of SP-null LECs were rescued by the addition of recombinant human (rh)SP., Conclusions: A simple IOL culture system was useful for the evaluation of the effects of SPARC and TGF-beta2 on PCO in vitro. The action of TGF-beta2 on LEC migration and proliferation is influenced by SPARC, a regulator of matrix-cell interactions. The results indicate a functional intersection between pathways activated by TGF-beta2 and SPARC in the formation of PCO.