A systematic approach to evaluate practice-based process- and outcome data applied to the treatment of neovascular age-related macular degeneration.

BACKGROUND: Following the principles of value-based health care, outcomes and processes of daily-practice eye care need to be systematically evaluated. We illustrate an approach that can be used to support data-driven quality improvements. We used patient data regarding the treatment of neovascular age-related macular degeneration (nAMD). METHODS: In a cohort study, we reviewed medical records of patients with nAMD confirmed on fluorescein angiography (FA). Patients were treated with intravitreal injections with bevacizumab; ranibizumab; or photodynamic therapy (PDT). Visual acuity (VA), ophthalmic exam results and treatments were recorded. VA was compared between treatments by linear mixed model. Diagnosis was re-evaluated on the original FAs. Outcome analysis was performed by 1) selecting VA as the relevant outcome parameter; 2) Preventing selection by comparing treatments with historical untreated cohort and cohorts from the literature, 3) correcting for confounding due to lesion type, and 4) identifying relevant process variables that affect the outcome. These were severity of disease at presentation, and doctor- and patient dependent process variables. RESULTS: In total, 473 eyes were included. At 12 months, change in VA was 0.54, 0.48, 0.09, and 0.07 LogMAR in the no-treatment, photodynamic therapy (PDT), bevacizumab, and ranibizumab groups, respectively. Lesion type on FA differed between groups. Diagnosis of nAMD could not be confirmed in 104 patients. Patient delay, inaccurate diagnosis and treatment intervals may have impacted outcomes. CONCLUSIONS: The effect of PDT was small to absent. Anti-VEGFs were effective and appeared as effective as in RCTs. Correct selection of a comparator cohort and addressing confounding, including confounding by indication and effect modification, are needed to achieve valid results and interpretation. Patient delay, diagnosis accuracy, indication for and application of treatment can potentially be improved to improve treatment outcomes. In a value-based care perspective, systematic evaluation of diagnostic accuracy, treatment indication, protocols, and outcomes of new interventions is needed at an early stage to improve outcomes.

Tracing the natural course of visual acuity and quality of life in neovascular age-related macular degeneration: a systematic review and quality of life study.

BACKGROUND: Describing the natural course of neovascular age-related macular degeneration (nAMD) is essential in discussing prognosis and treatment options with patients and to support cost-effectiveness studies. METHODS: First, we performed a literature search in PubMed, Embase, and Cochrane. We included randomized clinical trials and prospective observational studies reporting visual acuity (VA) in non-treated patients, 24 studies in total. We integrated VA data using best fit on Lineweaver-Burke plots and modelled with non-linear regression using reciprocal terms. Second, we performed a quality-of-life (QoL) study in nAMD patients. We measured VA with Radner reading charts and QoL with the Health Utilities Index issue 3 (HUI-3) questionnaire in 184 participants. We studied the relation VA-QoL with linear regression. Third, with Monte Carlo simulation, we integrated the VA model from the literature review and the relation VA-QoL from the QoL study. RESULTS: Visual acuity was 0.4 and 0.07 after 5 years in the better-seeing, and worse-seeing eye, respectively. After 4.3 years, VA was <0.5 in the better-seeing eye; <0.3 after 7 years; 0.05 after 17 years. QoL score decreased from 0.6 to 0.45 after 10 years. CONCLUSIONS: The natural course of nAMD in both eyes needs to be considered when informing patients. Visual acuity in the best eye decreases to below 0.5 in 4.3 years. This affects QoL significantly.

Distinguishing between Better and Worse Visual Acuity by Studying the Correlation with Quality of Life in Neovascular Age-Related Macular Degeneration.

PURPOSE: To determine whether there is a level of visual acuity (VA) in neovascular age-related macular degeneration (nAMD) above which the correlation of VA with disease-related quality of life (QoL) is significantly greater than below this level. DESIGN: An observational, cross-sectional study. PARTICIPANTS: A total of 184 patients with nAMD aged at least 50 years were included in the study. METHODS: In face-to-face interviews, we assessed QoL with the Macular Disease-Dependent Quality of Life (MacDQoL) questionnaire. We measured VA with standardized Radner reading charts. We used regression splines analysis with a single hinge point, with the MacDQoL score as the dependent variable and VA as the independent variable. The x-coordinate (VA) of the hinge point was varied and tested with each iteration. A second method of regression splines analysis was also performed, without a preset hinge point. MAIN OUTCOME MEASURES: The primary outcome measure is the cutoff point at or below which VA is associated with significantly less change in QoL than above this cutoff. The linear coefficients below and above the cutoff are defined as change in MacDQoL score per logarithm of the minimum angle of resolution (logMAR) unit of change in VA. RESULTS: With Snellen equivalent VA 0.05 (1.3 logMAR) or worse, the linear coefficient was 0.15. With VA better than 0.05, the linear coefficient was 2.40 (P value of the difference: 0.009). CONCLUSIONS: When VA is above 0.05, there is a stronger and significant relation between VA and QoL. At or below this level, the relation between VA and QoL approaches zero. With better VA, a difference in VA implies a significant difference in QoL. With poorer VA, a difference in VA is unlikely to imply a difference in QoL. Therefore, in treating nAMD, the aim should be to keep Snellen VA above 0.05 to have an impact on QoL. If it is certain that the best-corrected VA below 0.05 is permanent, these findings imply there may be less, if any, benefit to continue further treatment. This is to be evaluated on a case-by-case basis.

Analysis of rare variants in the CFH gene in patients with the cuticular drusen subtype of age-related macular degeneration.

PURPOSE: Age-related macular degeneration (AMD) and cuticular drusen (CD), a clinical subtype of AMD, have been linked to genetic variants in the complement factor H (CFH) gene. In this study, we aimed to investigate the frequency of rare variants in the CFH gene in 180 cases with CD. In addition, we aimed to determine the frequency of a previously reported rare, highly penetrant CFH variant (p.Arg1210Cys) in a Dutch-German non-CD-type AMD case-control cohort, and to describe the phenotype of patients carrying the p.Arg1210Cys variant. METHODS: Study subjects were selected from the European Genetic Database (EUGENDA), a joint AMD database of the Radboud University Medical Centre and the University Hospital of Cologne, and graded at the Cologne Image Reading Centre and Laboratory (CIRCL). Additionally, two CD cases were recruited from the VU Medical Centre in Amsterdam. The CFH gene was analyzed in 180 CD cases with Sanger sequencing. All identified variants were analyzed for potential damaging effects with prediction software tools Sorting Intolerant from Tolerant (SIFT) and Polymorphism Phenotyping (PolyPhen). In addition, we genotyped the p.Arg1210Cys variant in 813 non-CD type AMD cases and 1175 controls. RESULTS: Sequencing identified 11 rare, heterozygous missense variants, one frameshift variant, and one splice acceptor site variant in 16 CD cases. The p.Arg1210Cys variant was identified in two CD cases but was not identified in our Dutch-German non-CD-type AMD case-control cohort. CONCLUSIONS: The present study identified the presence of rare variants in the CFH gene in 16 (8.8%) of 180 patients with the CD subtype of AMD. The carriers of rare CFH variants displayed a significantly earlier age at onset than non-carriers (p=0.016). The rare missense variant p.Arg1210Cys was identified in two CD cases, but was not detected in 813 non-CD type AMD cases or in the 1,175 controls of our Dutch-German cohort. The current study suggests that the p.Arg1210Cys variant may be restricted to a subset of patients with the CD subtype of AMD. Detailed clinical phenotyping, including fluorescein angiography, of patients with AMD carrying the p.Arg1210Cys variant in other cohorts is required to confirm this finding.

Vogt-Koyanagi-Harada-Like Disease with Loss of Visual Acuity due to Sunitinib Treatment Restored after Switch in Therapy: A Case Report.

Introduction: In this paper, we report a case of visual impairment during treatment with sunitinib in a patient with metastatic renal cell carcinoma. Methods: Retrospective chart review was used. Case Presentation: We describe a 74-year-old male with metastatic renal cell carcinoma who was treated with sunitinib and experienced severe loss of visual acuity due to serous retinal detachment and intraretinal fluid. Upon discontinuation of sunitinib, the retinal fluid resolved, and visual acuity was restored. Conclusion: Serous retinal detachment has been described as a side effect of sunitinib use. Discontinuing sunitinib promptly resolved the subretinal fluid collections and restored vision.

Perspectives and Update on the Global Shortage of Verteporfin (Visudyne®).

An ongoing global shortage of verteporfin (Visudyne®) limits the treatment possibilities for several chorioretinal diseases, including central serous chorioretinopathy, choroidal hemangioma, and polypoidal choroidal vasculopathy. Verteporfin is required to perform photodynamic therapy in these ocular diseases. Therefore, the current situation has a substantial impact on eye care worldwide. The worldwide supply of verteporfin appears to be manufactured by a single factory, which is situated in the United States. The distribution of verteporfin is done by different companies for different regions of the world. Official communication on the shortage by the responsible companies has been scarce and over the past years several promises with regards to resolution of the shortage have not been fulfilled. The delivery of new batches of verteporfin is at irregular intervals, unpredictable, and may not be fairly balanced between different regions or countries in the world. To ensure a fair distribution of available verteporfin within a country, several measures can be taken. In the Netherlands, a national committee, consisting of ophthalmologists, is in place to arrange this. On the European level, the European Union and European Medicine Agency have plans to monitor medicine shortages more closely and to intervene if necessary. With a more intensified monitoring and regulation of medicine supplies, future impending shortages may be prevented. Remarkably, the amount of medicine shortages is increasing, having a significant and sometimes irreversible impact on patient care. Thus, efforts should be undertaken to minimize the consequences and, whenever possible, to prevent future medicine shortages.

Association of Risk Variants in the CFH Gene With Elevated Levels of Coagulation and Complement Factors in Idiopathic Multifocal Choroiditis.

Importance: Idiopathic multifocal choroiditis (MFC) is poorly understood, thereby hindering optimal treatment and monitoring of patients. Objective: To identify the genes and pathways associated with idiopathic MFC. Design, Setting, and Participants: This was a case-control genome-wide association study (GWAS) and protein study of blood plasma samples conducted from March 2006 to February 2022. This was a multicenter study involving 6 Dutch universities. Participants were grouped into 2 cohorts: cohort 1 consisted of Dutch patients with idiopathic MFC and controls, and cohort 2 consisted of patients with MFC and controls. Plasma samples from patients with idiopathic MFC who had not received treatment were subjected to targeted proteomics. Idiopathic MFC was diagnosed according to the Standardization of Uveitis Nomenclature (SUN) Working Group guidelines for punctate inner choroidopathy and multifocal choroiditis with panuveitis. Data were analyzed from July 2021 to October 2022. Main outcomes and measures: Genetic variants associated with idiopathic MFC and risk variants associated with plasma protein concentrations in patients. Results: This study included a total of 4437 participants in cohort 1 (170 [3.8%] Dutch patients with idiopathic MFC and 4267 [96.2%] controls; mean [SD] age, 55 [18] years; 2443 female [55%]) and 1344 participants in cohort 2 (52 [3.9%] patients with MFC and 1292 [96.1%] controls; 737 male [55%]). The primary GWAS association mapped to the CFH gene with genome-wide significance (lead variant the A allele of rs7535263; odds ratio [OR], 0.52; 95% CI, 0.41-0.64; P = 9.3 × 10-9). There was no genome-wide significant association with classical human leukocyte antigen (HLA) alleles (lead classical allele, HLA-A*31:01; P = .002). The association with rs7535263 showed consistent direction of effect in an independent cohort of 52 cases and 1292 control samples (combined meta-analysis OR, 0.58; 95% CI, 0.38-0.77; P = 3.0 × 10-8). In proteomic analysis of 87 patients, the risk allele G of rs7535263 in the CFH gene was strongly associated with increased plasma concentrations of factor H-related (FHR) proteins (eg, FHR-2, likelihood ratio test, adjusted P = 1.1 × 10-3) and proteins involved in platelet activation and the complement cascade. Conclusions and relevance: Results suggest that CFH gene variants increase systemic concentrations of key factors of the complement and coagulation cascades, thereby conferring susceptibility to idiopathic MFC. These findings suggest that the complement and coagulation pathways may be key targets for the treatment of idiopathic MFC.

Stargardt disease: monitoring incidence and diagnostic trends in the Netherlands using a nationwide disease registry.

PURPOSE: To assess the incidence of Stargardt disease (STGD1) and to evaluate demographics of incident cases. METHODS: For this retrospective cohort study, demographic, clinical and genetic data of patients with a clinical diagnosis of STGD1 were registered between September 2010 and January 2020 in a nationwide disease registry. Annual incidence (2014-2018) and point prevalence (2018) were assessed on the basis of this registry. RESULTS: A total of 800 patients were registered, 56% were female and 83% were of European ancestry. The incidence was 1.67-1.95:1,000,000 per year and the point prevalence in 2018 was approximately 1:22,000-1:19,000 (with and without 10% of potentially unregistered cases). Age at onset was associated with sex (p = 0.027, Fisher's exact); 1.9x more women than men were observed (140 versus 74) amongst patients with an age at onset between 10 and 19 years, while the sex ratio in other age-at-onset categories approximated one. Late-onset STGD1 (≥45 years) constituted 33% of the diagnoses in 2014-2018 compared to 19% in 2004-2008. Diagnostic delay (≥2 years between the first documentation of macular abnormalities and diagnosis) was associated with older age of onset (p = 0.001, Mann-Whitney). Misdiagnosis for age-related macular degeneration (22%) and incidental STGD1 findings (14%) was common in patients with late-onset STGD1. CONCLUSION: The observed prevalence of STGD1 in real-world data was lower than expected on the basis of population ABCA4 allele frequencies. Late-onset STGD1 was more frequently diagnosed in recent years, likely due to higher awareness of its phenotype. In this pretherapeutic era, mis- and underdiagnosis of especially late-onset STGD1 and the role of sex in STGD1 should receive special attention.

A systematic review of the adverse events of intravitreal anti-vascular endothelial growth factor injections.

BACKGROUND: Intravitreal ranibizumab and pegaptanib are registered for neovascular age-related macular degeneration. No formal safety study has been conducted for intravitreal bevacizumab. These anti-vascular endothelial growth factor (anti-VEGF) drugs are being used on a large scale in daily practice for different ocular diseases. The objective of the present study was to systematically assess and compare the incidences of adverse events of anti-VEGFs. METHODS: A systematic search was conducted in April 2009 with no date restrictions in PubMed, Embase, Toxline, and the Cochrane library. We used the terms pegaptanib, bevacizumab, ranibizumab, intravitreal, and specific and general terms for adverse events. Studies describing adverse events after anti-VEGF injections and the official safety data were included. RESULTS: Two hundred and seventy-eight articles were included, and the incidences of adverse events were calculated separately for effect, safety, and specific side effect studies. The incidences of serious ocular and nonocular adverse events were approximately below 1 per 100 injections for intravitreal bevacizumab, intravitreal ranibizumab, and intravitreal pegaptanib. Most mild ocular adverse events were below 5 per 100 injections. CONCLUSION: The reported rates of serious adverse events were low after anti-VEGF injections. There is no sufficient evidence to conclude that there is a difference in incidences between the anti-VEGFs.

Comparing the Efficacy of Bevacizumab and Ranibizumab in Patients with Retinal Vein Occlusion: The Bevacizumab to Ranibizumab in Retinal Vein Occlusions (BRVO) study, a Randomized Trial.

PURPOSE: Comparing the efficacy of intravitreal injections of bevacizumab to ranibizumab in the treatment of macular edema (ME) resulting from retinal vein occlusion (RVO). DESIGN: Comparative, randomized, double-masked, multicenter, noninferiority clinical trial. The noninferiority margin was 4 letters. PARTICIPANTS: Patients with vision loss resulting from ME secondary to a branch or (hemi) central RVO who might benefit from anti-vascular endothelial growth factor treatment were eligible for participation. METHODS: From June 2012 through February 2018, 277 participants were randomized to receive injections of 1.25 mg bevacizumab (n = 139) or 0.5 mg ranibizumab (n = 138). The follow-up was 6 months with a monthly dosing interval. MAIN OUTCOME MEASURES: The primary outcome was a change in visual acuity from baseline at 6 months. Changes in the central area thickness and safety were studied as secondary outcomes. RESULTS: The mean visual acuity (±standard deviation) improved, with 15.3±13.0 letters for bevacizumab and 15.5±13.3 letters for ranibizumab after 6 months of monthly treatment. The lower limit of the 2-sided 90% confidence interval was -1.724 letters, which is within the noninferiority margin of 4 letters. Even in the branch and (hemi-)central RVO subgroups, minimal differences were found in visual acuity outcomes between treatment arms. Changes in central area thickness on OCT at 6 months did not differ significantly between treatment groups, with a decrease of 287.0±231.3 µm in the bevacizumab group and 300.8±224.8 µm in the ranibizumab group. Severe adverse events (SAEs) were also distributed equally over both treatment groups: 10 participants (7.1%) in the bevacizumab group and 13 participants (9.2%) in the ranibizumab group experienced SAEs. CONCLUSIONS: This study showed, based on the change in visual acuity, that bevacizumab is noninferior to ranibizumab for patients with ME resulting from RVO of either subtype when receiving monthly injections for a period of 6 months. In addition, anatomic and safety outcomes did not differ between treatment groups. Based on our findings, bevacizumab may be an effective alternative to ranibizumab.

Extending the Spectrum of EYS-Associated Retinal Disease to Macular Dystrophy.

Purpose: To assess the phenotypic variability and natural course of inherited retinal diseases (IRDs) caused by EYS mutations. Methods: Multiethnic cohort study (N = 30) with biallelic EYS variants from a clinical IRD database (retinitis pigmentosa [RP], N = 27; cone-rod dystrophy [CRD], N = 1; and macular dystrophy, N = 2). In vitro minigene splice assay was performed to determine the effect on EYS pre-mRNA splicing of the c.1299+5_1299+8del variant in macular dystrophy patients. Results: We found 27 different EYS variants in RP patients and 7 were novel. The rate of visual field loss of the V4e isopter area was -0.84 ± 0.44 ln(deg2) per year, and the rate of visual acuity loss was 0.75 Early Treatment Diabetic Retinopathy Study letters per year. Ellipsoid zone width was correlated with area of the hyperautofluorescent ring, with rs = 0.78 and P < 0.001. Rate of decline in ellipsoid zone width was -57 ± 17 µm per year (P < 0.01) (n = 14) or -3.69% ± 0.51% from baseline per year (P < 0.001). An isolated CRD patient carried a homozygous EYS variant (c.9405T>A), previously identified in RP patients. Two siblings with macular dystrophy carried compound heterozygous EYS variants: c.1299+5_1299+8del and c.6050G>T. The former was novel and shown to result in skipping of exon 8, and the latter was a known RP variant. Conclusions: We report on EYS-associated macular dystrophy, extending the spectrum of EYS-associated IRDs. We observed heterogeneity between RP patients in age of onset and disease progression. Identical EYS variants were found in cases with RP, CRD, and macular dystrophy. Screening for EYS variants in CRD and macular dystrophy patients might increase the diagnostic yield in previously unsolved cases.

Effect of growth factors on proliferation and expression of growth factor receptors in a human lens epithelial cell line.

PURPOSE: To investigate the effect of basic fibroblast growth factor (bFGF), epidermal growth factor (EGF), insulin-like growth factor 1 (IGF-1), and transforming growth factor beta 2 (TGFbeta2) on proliferation of a human lens epithelial cell line (HLEC-SRA 01/04); the effect of bFGF and TGFbeta2 on proliferation of human lens epithelial cells (HLECs); and the expression of bFGF, EGF, IGF-1, and TGFbeta2 receptors in an HLEC-SRA 01/04 cell line. SETTING: Department of Ophthalmology, University of Ulm, Ulm, Germany. METHODS: Both HLEC and HLEC-SRA 01/04 were treated with 1 to 50 ng/mL bFGF and TGFbeta2) Additionally, HLEC-SRA 01/04 were cultured with EGF and IGF-1 at a concentration of 1 to 50 ng/mL for 48 hours in the presence of [3H]-thymidine. In all experiments, untreated serum-free negative controls were used. (3H)-thymidine incorporation as a direct measure of lens epithelial cell proliferation was assessed by liquid scintillation counting. The expression of bFGF, EGF, IGF-1, and TGFbeta2 receptors in HLEC-SRA 01/04 were analyzed by reverse transcriptase polymerase chain reaction (RT-PCR). Statistical analysis was performed using the 2-sample t test for the means. RESULTS: Proliferation of HLECs was dose dependently induced by bFGF and TGFbeta2, showing maximum effects at 10 ng/mL (P = .0003) and at 50 ng/mL (P < .0001), respectively. Proliferation of HLEC-SRA 01/04 was also induced by bFGF, showing slight but significant effects (P < .03). Additionally, HLEC-SRA 01/04 proliferation was dose-dependently induced by EGF with a maximum effect at 5 ng/mL (P < .01), IGF-1 with a maximum effect at 5 ng/mL (P < .0001), and TGFbeta2 with a maximum effect at 10 ng/mL (P < .0001) compared with the control. The RT-PCR analysis revealed bFGF, EGF, IGF-1, and TGFbeta2 receptor expression in the HLEC-SRA 01/04 cell line. CONCLUSIONS: The data showed that bFGF and TGFbeta2 are strong mitogens for HLEC. The HLEC-SRA 01/04 cell line derived from HLEC reacted to growth factors, with cell proliferation only to a lesser extent. Such quiescence of these cells, when compared with cells in primary culture, cannot be explained by the lack of respective receptors for growth factors. Further investigation of growth factor-induced responses of both cell types will provide new insight into the proliferative processes involved in postoperative secondary cataract formation.

A prospective, observational, open-label, multicentre study to investigate the daily treatment practice of ranibizumab in patients with neovascular age-related macular degeneration.

PURPOSE: The HELIOS (Health Economics with Lucentis in Observational Settings) study was designed on request of the Dutch Health Authority for an observational study to assess the effectiveness and safety of ranibizumab for neovascular age-related macular degeneration (wet AMD) in daily practice. METHODS: The HELIOS study was a 2-year prospective, observational, open-label, multicentre study involving 14 sites. Patients with wet AMD were enrolled and observed for a period of 24 months. The data were collected at baseline and at the visits closest around the time-points 3, 6, 12, 18 and 24 months after inclusion. RESULTS: Treatment with ranibizumab resulted in prevention of vision loss. The mean ETDRS score increased from 45.1 letters at baseline to 48.5 letters at 24 months. This was achieved with a mean of 7.8 injections over 24 months. Stabilization of visual acuity was also reflected by the scores on the quality of life EQ-5D questionnaire, which did not significantly change over the study period. The more subjective EQ-VAS questionnaire showed an overall improvement. The VFQ-25 questionnaire was also mostly stable over time. After 24 months, 32.2% of the patients gained ≥1 letter and 17.1% gained >15 letters. Patients completing the loading phase were better responders, as demonstrated by increased long-term visual acuity. In addition, ranibizumab was well tolerated and had a safety profile commonly seen in routine clinical practice. CONCLUSION: This study demonstrates that also in daily practice ranibizumab was effective in preventing vision loss over a period of 24 months. No new safety findings were identified.

Cytomegalovirus retinitis in a patient treated with anti-tumor necrosis factor alpha antibody therapy for rheumatoid arthritis.

BACKGROUND: Anti-tumor necrosis factor alpha (anti-TNF- alpha ) antibodies have been used for the treatment of chronic inflammatory diseases such as rheumatoid arthritis (RA) and psoriasis arthritis. Such antibody therapies result in a severe interference with the patient's immune system. Increased rates of upper respiratory tract infection, reactivation of latent tuberculosis, and other systemic infectious diseases have been reported among patients receiving anti-TNF- alpha antibodies. METHODS: As a note of caution, we describe a 57-year-old woman who received therapy with anti-TNF- alpha antibodies for RA refractory to methotrexate. After almost 2 years of treatment, she developed a severe cytomegalovirus (CMV) retinitis of the right eye. RESULTS: Laboratory assays revealed an immune status with nearly total loss of the cellular immune response and partial reduction of the humoral immune response. Intravenous treatment with ganciclovir, followed by oral administration of valganciclovir, resulted in an ophthalmological remission. Cessation of immunosuppressive therapy led to partial immunological reconstitution in the patient. Six months after discontinuation of immunosuppressive therapy, CMV retinitis of the left eye occurred but was treated successfully with a second course of oral valganciclovir. CONCLUSION: In the light of this first reported case of a serious CMV infection following therapy with anti-TNF- alpha antibodies, CMV infection should be considered in symptomatic patients.

Effect of extracellular matrix on proliferation and differentiation of porcine lens epithelial cells.

BACKGROUND: Proliferation and differentiation of lens epithelial cells (LECs) are important mechanisms of secondary cataract formation. After extracapsular cataract extraction the extracellular matrix (ECM) around the remaining LECs is altered compared with the intact lens. This study investigated the effects of different ECMs on cell proliferation and alpha-smooth muscle actin (alpha-SMA) expression, a marker for myofibroblasts, in cultured porcine LECs. METHODS: Porcine LECs were cultured for 3 days (cell proliferation assay) or 4 days (alpha-SMA expression) on wells and glass cover slips, respectively, coated with laminin, fibronectin, type I collagen or type IV collagen. LECs cultured on uncoated wells or cover slips served as control. Proliferative response was measured by [(3)H]-thymidine incorporation into DNA. alpha-SMA was detected immunocytochemically with a mouse monoclonal antibody, and the relative numbers of alpha-SMA-positive cells were calculated. Statistical analysis was performed using Student's unpaired t-test. RESULTS: Cell proliferation was significantly increased by coating with fibronectin (10,320.5+/-6,073 counts per minute; p<0.0001) (mean +/- SD), type I collagen (12,507.3+/-3,914.2 CPM; p<0.0001) and type IV collagen (9,591.4+/-4,088 CPM; p<0.0001) compared with control (1,876.5+/-998 CPM), whereas coating with laminin had no effect (1,760.8+/-812.6 CPM; p=0.7271). The ratio of alpha-SMA-positive LECs cultured on uncoated cover slips for a period of 4 days was 12.2+/-3.51%. This ratio was significantly increased by coating with fibronectin (24.3+/-4.56%; p=0.0001) and type I collagen (21.2+/-8.48%; p=0.0142). Coating with laminin (9.8+/-3.67%; p=0.1682) and type IV collagen (9.0+/-7.09 %; p=0.2491) slightly decreased alpha-SMA expression, but this effect was not statistically significant. CONCLUSIONS: Fibronectin and type I collagen stimulated both cell proliferation and alpha-SMA expression in cultured porcine LECs. Because fibronectin and type I collagen are not normally present in the adult lens, their possible introduction into the lens capsule after cataract surgery may play a critical role in the development of posterior capsule opacification.