ROCK-isoform-specific polarization of macrophages associated with age-related macular degeneration.

Age is a major risk factor in age-related macular degeneration (AMD), but the underlying cause is unknown. We find increased Rho-associated kinase (ROCK) signaling and M2 characteristics in eyes of aged mice, revealing immune changes in aging. ROCK isoforms determine macrophage polarization into M1 and M2 subtypes. M2-like macrophages accumulated in AMD, but not in normal eyes, suggesting that these macrophages may be linked to macular degeneration. M2 macrophages injected into the mouse eye exacerbated choroidal neovascular lesions, while M1 macrophages ameliorated them, supporting a causal role for macrophage subtypes in AMD. Selective ROCK2 inhibition with a small molecule decreased M2-like macrophages and choroidal neovascularization. ROCK2 inhibition upregulated M1 markers without affecting macrophage recruitment, underlining the plasticity of these macrophages. These results reveal age-induced innate immune imbalance as underlying AMD pathogenesis. Targeting macrophage plasticity opens up new possibilities for more effective AMD treatment.

Blood vessel endothelial VEGFR-2 delays lymphangiogenesis: an endogenous trapping mechanism links lymph- and angiogenesis.

Angio- and lymphangiogenesis are inherently related processes. However, how blood and lymphatic vessels regulate each other is unknown. This work introduces a novel mechanism explaining the temporal and spatial relation of blood and lymphatic vessels. Vascular endothelial growth factor-A (VEGF-A) surprisingly reduced VEGF-C in the supernatant of blood vessel endothelial cells, suggesting growth factor (GF) clearance by the growing endothelium. The orientation of lymphatic sprouting toward angiogenic vessels and away from exogenous GFs was VEGF-C dependent. In vivo molecular imaging revealed higher VEGF receptor (R)-2 in angiogenic tips compared with normal vessels. Consistently, lymphatic growth was impeded in the angiogenic front. VEGF-C/R-2 complex in the cytoplasm of VEGF-A-treated endothelium indicated that receptor-mediated internalization causes GF clearance from the extracellular matrix. GF clearance by receptor-mediated internalization is a new paradigm explaining various characteristics of lymphatics.

Role of tumour necrosis factor-α (TNFα) in the functional properties of hyalocytes.

BACKGROUND/AIM: Tumour necrosis factor-α (TNFα) is an inflammatory cytokine that is upregulated in various vitreoretinal diseases including uveitis and diabetic retinopathy. Recently, our studies have indicated that hyalocytes contribute to the pathogenesis of these diseases. However, the impact of TNFα on the functional properties of hyalocytes is unknown. METHODS: Hyalocytes were isolated from bovine eyes. Cellular proliferation, migration and gel contraction in response to TNFα and the other inflammatory cytokines were analysed by thymidine uptake, Boyden's chamber assay and collagen gel contraction assay, respectively. Furthermore, we estimated the effect of dexamethasone on these properties of hyalocytes. RESULTS: TNFα promoted proliferation, migration and gel contraction by hyalocytes. Dexamethasone inhibited TNFα-induced proliferation but not migration. Dexamethasone did not inhibit TNFα-induced gel contraction but further increased contraction. Furthermore, dexamethasone inhibited TNFα-induced extracellular signal-related kinase (ERK)1/2 phosphorylation in hyalocytes. CONCLUSION: This study indicates that TNFα in vitreous and retina causes activation of hyalocytes, and the activated hyalocytes contribute to the pathogenesis of inflammatory vitreoretinal diseases. Steroid treatment appears to inhibit the activation of hyalocytes in the early stages of the diseases, but might have adverse effects in the late stage through membrane contraction.

Retinitis pigmentosa associated with asteroid hyalosis.

BACKGROUND: Asteroid hyalosis (AH) is a condition in which cream-colored or white spherical particles are suspended in the vitreous body. Asteroid hyalosis is considered not to cause decreased vision or any other visual symptoms except in rare cases. There have been a few reports of AH in patients with retinitis pigmentosa (RP). METHODS: To assess the prevalence of AH in patients with RP, 320 patients with typical forms of RP were studied. One patient was offered a standard three-port vitrectomy, and the spherical particles obtained from her vitrectomy sample were analyzed using an energy-dispersive x-ray spectrometer. RESULTS: Ten patients (two men and eight women) developed AH. Among them, four had bilateral AH and two had rapidly increasing vitreous opacity that led to decreased vision. One patient was a 48-year-old woman with progressive AH in the left eye. After treatment with a vitrectomy, her vision improved from 0.4 to 0.8. The spherical particles were composed of mainly calcium and phosphorus. CONCLUSION: The prevalence of AH in RP was higher than in previous reports, and we encountered two rare cases of progressive AH with decreased vision. We conclude that AH might lead to decreased vision in patients with RP.

ROCK as a Therapeutic Target of Diabetic Retinopathy.

The increasing global prevalence of diabetes is a critical problem for public health. In particular, diabetic retinopathy, a prevalent ocular complication of diabetes mellitus, causes severe vision loss in working population. A better understanding of the pathogenesis and the development of new pharmacologic treatments are needed. This paper describes the relevance between Rho/ROCK pathway and the pathogenesis of diabetic retinopathy from its early to late stages. Moreover, the therapeutic potential of ROCK inhibitor in the total management of diabetic retinopathy is discussed.

Histopathology of neovascular tissue from eyes with proliferative diabetic retinopathy after intravitreal bevacizumab injection.

PURPOSE: To examine the histopathologic effect of a single intravitreal injection of bevacizumab on newly formed vessels in eyes with proliferative diabetic retinopathy (PDR). DESIGN: Interventional case series and laboratory investigation. METHODS: Two days after intravitreal injection of bevacizumab (1.25 mg/eye), pars plana vitrectomy or trabeculectomy was performed for the treatment of PDR or neovascular glaucoma (NVG) associated with PDR. Ten surgically removed preretinal proliferative tissues and 6 deep scleral flaps containing trabecular meshwork were fixed in 2% glutaraldehyde or 4% paraformaldehyde and were subjected to transmission electron microscopic analysis, immunohistochemical analysis, and terminal deoxyuridiine triphosphate (dUTP) nick-end labeling staining. Two surgically removed preretinal proliferative tissues and 2 deep scleral flaps from patients with PDR and NVG, but without preoperative intravitreal injection of bevacizumab (IVB), served as controls. RESULTS: In control tissues, vascular endothelial cells possessed many fenestrations and were accompanied by pericytes. Apoptotic vascular endothelial cells frequently were observed in tissue after intravitreal injection of bevacizumab, whereas they were not observed in control tissues. Additionally, no apparent fenestration was observed in newly formed vessels from either proliferative tissue or trabecular meshwork after intravitreal injection of bevacizumab. In both PDR and NVG tissues after intravitreal injection of bevacizumab, overexpression of smooth muscle actin was observed in newly formed vessels, suggesting that the treatment may have increased pericytes on the vasculature as compared with control tissue. CONCLUSIONS: Intravitreal injection of bevacizumab may induce changes in immature, newly formed vessels of PDR or NVG tissue, leading to endothelial apoptosis with vascular regression, while inducing normalization of premature vessels by increasing pericyte coverage and reducing vessel fenestration.

Antiangiogenic drugs in the management of ocular diseases: Focus on antivascular endothelial growth factor.

Age-related macular degeneration (AMD) complications are the leading cause of severe vision loss among the aging population in the many western countries. The introduction of molecular inhibitors of vascular endothelial growth factor (VEGF), such as pegaptanib, ranibizumab, and bevacizumab, as treatments for wet AMD has provided new hope for affected patients. Now we have these treatment options, which have the possibility to improve or maintain visual acuity for patients suffering from AMD. The treatment needs to be optimized and this is in progress. Based on emerging evidence, adopting a variable VEGF inhibitor-dosing strategy guided by visual acuity assessment and optical coherence tomography are now being tried to reduce the frequency of injections. VEGF inhibitors in combination with photodynamic therapy are another way to optimize treatment. Physicians are waiting for new guidelines for the management of AMD and the results of current and upcoming trials systematically addressing these issues will be expected to provide it.

Antiangiogenic mechanisms of simvastatin in retinal endothelial cells.

BACKGROUND: While statins have an anti-angiogenic property, their underlying mechanisms are not fully understood. We investigated intracellular mechanisms of simvastatin-mediated reduction in VEGF-induced signalings. METHODS: The effects of simvastatin on cell proliferation and viability were evaluated by [(3)H]-thymidine incorporation in retinal endothelial cells (RECs) and cell counting. The impact of simvastatin on VEGF-induced phosphorylation of p44/42 mitogen-activated protein (MAP) kinase, myosin light chain (MLC), and VEGF-receptor (VEGFR) 2 were examined by Western blotting. Involvement of the mevalonate pathway in VEGF-induced signaling was also examined. RESULTS: Simvastatin (1 and 10 microM) suppressed VEGF-induced RECs proliferation in a concentration-dependent manner, without affecting cell viability. Simvastatin significantly inhibited VEGF-induced phosphorylation of VEGFR2 and its downstream mediators, p44/42 MAP kinase and MLC. Mevalonate completely reversed VEGF-induced VEGFR2 phosphorylation, but only partially reversed the phosphorylation of p44/42 MAP kinase and MLC. CONCLUSION: These data indicate that simvastatin exerts its anti-angiogenic effects through the reduction of VEGFR2 phosphorylation in RECs at least in part. However, there seems to be both mevalonate-dependent and independent pathway in simvastatin's anti-angiogenic property.

Prevalence and systemic risk factors for retinal vein occlusion in a general Japanese population: the Hisayama study.

PURPOSE: To examine the prevalence of retinal vein occlusion (RVO) and its systemic relevant factors in a general Japanese population aged 40 years or older. METHODS: In 1998, 1775 Hisayama residents consented to participate in the study. Each participant underwent a comprehensive examination that included ophthalmic testing. RVO was determined by grading color fundus photographs. Logistic regression analysis was performed to determine risk factors for RVO. RESULTS: Of the 1775 subjects examined, 38 had RVO. The prevalence of RVO was 2.1% (2.0% for branch RVO and 0.2% for central RVO). After adjustment for age and sex, it was found that systolic and diastolic blood pressures, hypertension, and hematocrit were significantly associated with RVO. In multivariate analysis, age (per 10 years; odds ratio [OR], 1.47; 95% confidence interval [CI], 1.04-2.08), hypertension (OR, 4.25; 95% CI, 1.82-9.94), and hematocrit (per 10%; OR, 3.09; 95% CI, 1.10-1.22) remained independently significant risk factors for RVO. Both high-normal blood pressure and hypertension were significantly associated with RVO. Furthermore, compared with normotensive subjects without high hematocrit, the likelihood of RVO was markedly high in subjects having both high blood pressure and high hematocrit (age- and sex-adjusted OR, 36.0; 95% CI, 4.43-292). CONCLUSIONS: The findings suggest that the prevalence of RVO is higher in the Japanese than in other Asians or Caucasians and that older age, higher hematocrit, and both hypertension and high-normal blood pressure are significant risk factors for RVO in the Japanese.

Comprehensive analysis of inflammatory immune mediators in vitreoretinal diseases.

Inflammation affects the formation and the progression of various vitreoretinal diseases. We performed a comprehensive analysis of inflammatory immune mediators in the vitreous fluids from total of 345 patients with diabetic macular edema (DME, n = 92), proliferative diabetic retinopathy (PDR, n = 147), branch retinal vein occlusion (BRVO, n = 30), central retinal vein occlusion (CRVO, n = 13) and rhegmatogenous retinal detachment (RRD, n = 63). As a control, we selected a total of 83 patients with either idiopathic macular hole (MH) or idiopathic epiretinal membrane (ERM) that were free of major pathogenic intraocular changes, such as ischemic retina and proliferative membranes. The concentrations of 20 soluble factors (nine cytokines, six chemokines, and five growth factors) were measured simultaneously by multiplex bead analysis system. Out of 20 soluble factors, three factors: interleukin-6 (IL-6), interleukin-8 (IL-8), and monocyte chemoattractant protein-1 (MCP-1) were significantly elevated in all groups of vitreoretinal diseases (DME, PDR, BRVO, CRVO, and RRD) compared with control group. According to the correlation analysis in the individual patient's level, these three factors that were simultaneously increased, did not show any independent upregulation in all the examined diseases. Vascular endothelial growth factor (VEGF) was significantly elevated in patients with PDR and CRVO. In PDR patients, the elevation of VEGF was significantly correlated with the three factors: IL-6, IL-8, and MCP-1, while no significant correlation was observed in CRVO patients. In conclusion, multiplex bead system enabled a comprehensive soluble factor analysis in vitreous fluid derived from variety of patients. Major three factors: IL-6, IL-8, and MCP-1 were strongly correlated with each other indicating a common pathway involved in inflammation process in vitreoretinal diseases.

Nine-year incidence and risk factors for age-related macular degeneration in a defined Japanese population the Hisayama study.

PURPOSE: To estimate the 9-year incidence and risk factors for age-related macular degeneration (AMD) in a general Japanese population. DESIGN: Population-based, cohort study. PARTICIPANTS: In 1998, a total of 1775 Hisayama residents aged >or=40 years underwent a baseline eye examination. Of those, 1401 subjects (78.9%) took part in the follow-up eye examination in 2007 and were enrolled in the present study. METHODS: At both time points, the characteristics of AMD were determined by grading color fundus photographs using the Wisconsin Age-Related Maculopathy Grading System. MAIN OUTCOME MEASURES: Incident early and late AMD. RESULTS: The age-standardized, 9-year cumulative incidence of early AMD was 10.0%, and that of late AMD was 1.4%. Men were found to have a significantly higher incidence of late AMD than women (age-adjusted odds ratio [OR], 2.97; 95% confidence interval [CI], 1.25-7.09). The incidence of both early and late AMD increased significantly with age. Multiple logistic regression analysis showed that older age (per 1 year; OR, 1.10; 95% CI, 1.05-1.16), smoking habits (OR, 3.98; 95% CI, 1.07-14.7), and higher circulating white blood cell (WBC) count (per 1000 cells/mm(3)) (OR, 1.38; 95% CI, 1.07-1.79) were significantly associated with the development of late AMD. CONCLUSIONS: Our findings suggest that the 9-year incidences of late AMD are lower among the Japanese than among white people in Western countries, and it is higher than among black people. Smoking habits and higher circulating WBC count are significant risk factors for the development of late AMD in the Japanese.

Equivalent tamponade by room air as compared with SF(6) after macular hole surgery.

BACKGROUND: To evaluate the effect of tamponade by room air after vitrectomy for the treatment of idiopathic macular hole (MH). METHODS: There were 156 eyes of 151 patients studied. The patients' ages ranged from 35 to 88 years old (mean: 65.1 years). After conventional pars plana vitrectomy with internal limiting membrane peeling, fluid air exchange was performed using 20% SF(6) (Gas group: 91 eyes) or room air (Air group: 65 eyes). Surgical outcomes were retrospectively analyzed. RESULTS: Mean preoperative hole diameter was 352 microm in the Gas group and 370 microm in the Air group (P = 0.558). The closure rate of all cases was 91.0% after first surgery and 98.7% at last follow-up. The primary closure rate was 90.1% in the Gas group after 7.44 +/- 1.66 (mean +/- SD) days prone positioning period, and 92.3% in the Air group after 3.83 +/- 0.97 days of prone positioning. There was significant difference in prone positioning period (P < 0.0001), but not in the first closure rate (P = 0.132). CONCLUSION: This study suggests that room air may have an equivalent tamponade effect, in spite of the shorter prone positioning period, than SF(6) after MH surgery.

Anatomical findings of vitreoretinal interface in eyes with asteroid hyalosis.

PURPOSE: To investigate the anatomical features of vitreoretinal interface in eyes with asteroid hyalosis (AH) with optical coherence tomography (OCT) and intravitreal triamcinolone acetonide (TA) during vitreous surgery. METHODS: This study was an interventional clinical case series. Records relating to ten eyes from ten patients who underwent a TA-assisted vitrectomy for the treatment of diverse vitreoretinal diseases complicated with AH. The posterior vitreoretinal interface was examined by preoperative OCT and by intraoperative visualization of posterior vitreous cortex utilizing TA. RESULTS: In eight of ten AH eyes, preoperative OCT revealed abnormal vitreoretinal adhesions. In four of these eight eyes, posterior vitreoschisis could be seen on OCT. In the other four of these eight eyes, a clear no posterior vitreous detachment (PVD) pattern could be seen on OCT. Although posterior vitreous cortex could not be clearly identified with preoperative OCT in two of ten AH eyes, a complete PVD was refuted by intraoperative visualization of the posterior vitreous cortex with TA identical to the other eight eyes. CONCLUSION: These results indicate that complete PVD appears to be unlikely to occur in eyes with AH. In addition, spontaneous PVD in eyes with AH might lead to vitreoschisis or residual whole layer or posterior vitreous cortex, possibly due to anomalous vitreoretinal adhesion.

[Preventive strategy for the treatment of diabetic vitreoretinopathy].

Despite considerable recent advances in vitreoretinal surgery, generally performed in more advanced stages of diabetic vitreoretinopathy (DVR), a satisfying visual acuity cannot always be achieved. Even in the early DVR stages that might be detected by routine eye exams, management of general factors, such as blood glucose concentration and blood pressure, currently constitutes the only proven preventive measures. New approaches for amelioration and treatment of DVR are needed. The Hisayama study, an ongoing prospective cohort study of cardiovascular disease and its risk factors in a community in Hisayama Town adjoining Fukuoka City, revealed that the cut-off point for diagnostic fasting glucose level is lower (116 mg/dl) than that of the current diagnostic criteria (126 mg/ dl), indicating that more rigid diagnostic criteria might reduce the incidence of DVR in the Japanese population. In early stages of DVR, leukocyte adhesion in the retinal microvasuculature substantially contributes to DVR. We investigated the involvement of the Rho/ ROCK pathway in diabetic microvasculopathy and the therapeutic potential of fasudil, a selective ROCK inhibitor, and demonstrated that the Rho/ROCK pathway plays a critical role in leukocyte adhesion in diabetic retinal microvasculature and endothelial damage. Fasudil protects the vascular endothelium at least in part by inhibiting neutrophil adhesion and reducing neutrophil-induced endothelial injury via endothelial nitric oxide. In later stages of DVR, namely proliferative diabetic retinopathy, tractional retinal detachment associated with a cicatrical contraction of proliferative membranes can cause severe vision loss. We demonstrated the possible involvement of hyalocytes in proliferative membrane formation and its contraction mainly mediated through the function of TGF-beta 2 resulting in myofibroblastic transdifferentiation and phosphorylation of the myosin light chain, a downstream mediator of ROCK. ROCK inhibition by fasudil or statins successfully inhibited cicatrical contraction of the proliferative membranes both in vitro and in vivo. Further studies for direct evidence demonstrating whether altered diagnostic criteria of diabetes may lead to a lower incidence of DVR and determination of the therapeutic potential of ROCK inhibition in the clinic could provide new avenues of intervention for inhibiting DVR.

Rho kinase inhibition by fasudil ameliorates diabetes-induced microvascular damage.

OBJECTIVE: Leukocyte adhesion in retinal microvasuculature substantially contributes to diabetic retinopathy. Involvement of the Rho/Rho kinase (ROCK) pathway in diabetic microvasculopathy and therapeutic potential of fasudil, a selective ROCK inhibitor, are investigated. RESEARCH DESIGN AND METHODS: Localization of RhoA/ROCK and Rho activity were examined in retinal tissues of rats. Impact of intravitreal fasudil administration on retinal endothelial nitric oxide synthase (eNOS) and myosin phosphatase target protein (MYPT)-1 phosphorylation, intercellular adhesion molecule-1 (ICAM-1) expression, leukocyte adhesion, and endothelial damage in rat eyes were investigated. Adhesion of neutrophils from diabetic retinopathy patients or nondiabetic control subjects to cultured microvascular endothelial cells was quantified. The potential of fasudil for endothelial protection was investigated by measuring the number of adherent neutrophils and terminal transferase-mediated dUTP nick-end labeling-positive endothelial cells. RESULTS: RhoA and ROCK colocalized predominantly in retinal microvessels. Significant Rho activation was observed in retinas of diabetic rats. Intravitreal fasudil significantly increased eNOS phosphorylation, whereas it reduced MYPT-1 phosphorylation, ICAM-1 expression, leukocyte adhesion, and the number of damaged endothelium in retinas of diabetic rats. Neutrophils from diabetic retinopathy patients showed significantly higher adhesion to cultured endothelium and caused endothelial apoptosis, which was significantly reduced by fasudil. Blockade of the Fas-FasL interaction prevented endothelial apoptosis. The protective effect of fasudil on endothelial apoptosis was significantly reversed by Nomega-nitro-l-arginine methyl ester, a NOS inhibitor, whereas neutrophil adhesion remained unaffected. CONCLUSIONS: The Rho/ROCK pathway plays a critical role in diabetic retinal microvasculopathy. Fasudil protects the vascular endothelium by inhibiting neutrophil adhesion and reducing neutrophil-induced endothelial injury. ROCK inhibition may become a new strategy in the management of diabetic retinopathy, especially in its early stages.

An early "reopening" case of idiopathic macular hole; supportive usefulness of fundus autofluorescence.

BACKGROUND: Anatomical closure of macular holes (MH) is now largely confirmed by optical coherence tomography (OCT). Fundus autofluorescence (FAF) is also helpful in diagnosis and anatomical estimation of MH. We report a case of early reopening of anatomically closed MH, 2 days after release from face-down positioning where FAF abnormalities proceeded OCT findings. METHODS: A case report. A 67-year-old woman underwent vitrectomy with brilliant blue G-assisted ILM peeling for the treatment of full-thickness stage 4 MH (diameter 578 microm). FAF and OCT were used to evaluate the patient. RESULTS: On post operative day 3, OCT showed anatomical closure of MH, but FAF persistently demonstrated hyperfluorescence in the fovea. On post operative day 5, 2 days after termination of positioning, OCT showed reopening of the MH. Intra-vitreous injection of 50 % sulfur hexafluoride (SF(6)) gas was performed followed by face-down positioning again. Fourteen days after surgery, we confirmed the findings of both the anatomical closure in OCT and hypofluorescence on FAF. Two months later, MH remained closed. CONCLUSIONS: FAF might be a useful measure as a supportive method to guide release from posture restriction.

Role of TGF-beta in proliferative vitreoretinal diseases and ROCK as a therapeutic target.

Cicatricial contraction of preretinal fibrous membrane is a cause of severe vision loss in proliferative vitreoretinal diseases such as proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). TGF-beta is overexpressed in the vitreous of patients with proliferative vitreoretinal diseases and is also detectable in the contractile membranes. Therefore, TGF-beta is presumed to contribute to the cicatricial contraction of the membranes, however, the underlying mechanisms and TGF-beta's importance among various other factors remain to be elucidated. Vitreous samples from PDR or PVR patients caused significantly larger contraction of hyalocyte-containing collagen gels, compared with nonproliferative controls. The contractile effect was strongly correlated with the vitreal concentration of activated TGF-beta2 (r = 0.82, P < 0.0001). PDR or PVR vitreous promoted expression of alpha-smooth muscle actin (alpha-SMA) and phosphorylation of myosin light chain (MLC), a downstream mediator of Rho-kinase (ROCK), both of which were dramatically but incompletely suppressed by TGF-beta blockade. In contrast, fasudil, a potent and selective ROCK inhibitor, almost completely blocked the vitreous-induced MLC phosphorylation and collagen gel contraction. Fasudil disrupted alpha-SMA organization, but it did not affect its vitreal expression. In vivo, fasudil significantly inhibited the progression of experimental PVR in rabbit eyes without affecting the viability of retinal cells by electroretinographic and histological analyses. These results elucidate the critical role of TGF-beta in mediating cicatricial contraction in proliferative vitreoretinal diseases. ROCK, a key downstream mediator of TGF-beta and other factors might become a unique therapeutic target in the treatment of proliferative vitreoretinal diseases.

Potent inhibition of cicatricial contraction in proliferative vitreoretinal diseases by statins.

OBJECTIVE: Despite tremendous progress in vitreoretinal surgery, certain postsurgical complications limit the success in the treatment of proliferative vitreoretinal diseases (PVDs), such as proliferative diabetic retinopathy (PDR) and proliferative vitreoretinopathy (PVR). One of the most significant complications is the cicatricial contraction of proliferative membranes, resulting in tractional retinal detachment and severe vision loss. Novel pharmaceutical approaches are thus urgently needed for the management of these vision-threatening diseases. In the current study, we investigated the inhibitory effects of statins on the progression of PVDs. RESEARCH DESIGN AND METHODS: Human vitreous concentrations of transforming growth factor-beta2 (TGF-beta2) were measured by enzyme-linked immunosorbent assay. TGF-beta2-and vitreous-dependent phosphorylation of myosin light chain (MLC), a downstream mediator of Rho-kinase pathway, and collagen gel contraction simulating cicatrical contraction were analyzed using cultured hyalocytes. Inhibitory effects of simvastatin on cicatrical contraction were assessed both in vitro and in vivo. RESULTS: Human vitreous concentrations of TGF-beta2 were significantly higher in the samples from patients with PVD compared with those without PVD. Simvastatin inhibited TGF-beta2-dependent MLC phosphorylation and gel contraction in a dose- and time-dependent manner and was capable of inhibiting translocation of Rho protein to the plasma membrane in the presence of TGF-beta2. Vitreous samples from patients with PVD enhanced MLC phosphorylation and gel contraction, whereas simvastatin almost completely inhibited these phenomena. Finally, intravitreal injection of simvastatin dose-dependently prevented the progression of diseased states in an in vivo model of PVR. CONCLUSIONS: Statins might have therapeutic potential in the prevention of PVDs.