Extracellular matrix gene expression in human trabecular meshwork cells following mechanical fluid flow stimulation

AIM: To investigate changes in extracellular matrix(ECM) gene expression in human trabecular meshwork(HTM) cells in response to mechanical fluid flow stimulation.METHODS: HTM cells were grown on a glass plate coated with 0.02% type Ⅰ collagen(COL) and exposed to shear stress(0, 0.2, 1.0 dyne/cm;) for 12 h.Changes in genes related to the ECM were evaluated by real-time reverse transcriptase-polymerase chain reaction.Phosphorylation of Smad2 protein was investigated by Western blotting.RESULTS: After mechanical stimulation, COL type 4 alpha 2, COL type 6 alpha 1, and fibronectin-1 mRNA were significantly higher than the static control(P<0.05, <0.05, and <0.01, respectively).The metalloproteinase-2 and plasminogen activator inhibitor-1 mRNA were significantly higher than the static control(P<0.05 and <0.01, respectively), while the differences in the tissue inhibitors of metalloproteinases-2 mRNA were not significant.The phosphorylation of Smad2 levels was significantly higher compared to the static control cells.CONCLUSION: Changes in the expressions of genes associated ECM metabolism result in HTM cells after mechanical stimulation.The mechanical stimulation of the aqueous humor to the trabecular meshwork may promote ECM turnover and contribute to intraocular pressure homeostasis.

Morphological changes in intraretinal microvascular abnormalities after anti-VEGF therapy visualized on optical coherence tomography angiography

Background:To examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities(IRMAs)in response to anti-vascular endothelial growth factor(anti-VEGF)treatment,documented by optical coherence tomography angiography(OCTA)in diabetic eyes.Methods:In this retrospective study,IRMAs were evaluated with multimodal imaging(fundus photography,fluorescein angiography,OCTA)in treatment-naïve diabetic eyes before and after anti-VEGF treatment for diabetic macular edema(DME)and/or proliferative diabetic retinopathy(PDR)and compared to diabetic control eyes with similar diabetic retinopathy(DR)severity that did not receive anti-VEGF therapy.The morphological characteristics of IRMAs on enface OCTA imaging were graded by masked readers at baseline,then after anti-VEGF therapy in treated eyes or after observation in control eyes.Characterization of interval changes in an IRMA were based on the following parameters:branching,vessel caliber and area of adjacent capillary non-perfusion.Results:The treated group included 45 IRMA foci from 15 eyes of 11 patients,while the control group included 27 IRMA foci from 15 eyes of 14 patients.Following anti-VEGF treatment,enface OCTA demonstrated that 14 foci of IRMA(31%)demonstrated regression with normalization of appearance of the capillary bed,20 IRMAs(44%)remained unchanged,six IRMAs(13%)progressed with enlargement or development of new IRMAs and five IRMAs(11%)demonstrated complete obliteration defined as IRMA disappearance with advancing capillary drop-out.In the control group,17 IRMA(63%)remained stable,8 IRMAs(29.6%)progressed and 2 experienced total obliteration(7.4%).The difference in rank order between the two groups was statistically significant(p=0.022).Conclusions:In eyes with DR status post anti-VEGF therapy,foci of IRMAs have a variable course demonstrating one of four possible outcomes:regression,stabilit,progression or complete obliteration.In contrast,none of the untreated control diabetic eyes demonstrated regression of IRMAs,consistent with known progression of DR severity in high risk eyes.Morphologic evaluation of IRMAs with OCTA may help to monitor changes in retinal blood flow as well as the response to anti-VEGF treatment.

Morphological changes in intraretinal microvascular abnormalities after anti-VEGF therapy visualized on optical coherence tomography angiography

Background:To examine the baseline morphological characteristics and alterations in intraretinal microvascular abnormalities(IRMAs)in response to anti-vascular endothelial growth factor(anti-VEGF)treatment,documented by optical coherence tomography angiography(OCTA)in diabetic eyes.Methods:In this retrospective study,IRMAs were evaluated with multimodal imaging(fundus photography,fluorescein angiography,OCTA)in treatment-naive diabetic eyes before and after anti-VEGF treatment for diabetic macular edema(DME)and/or proliferative diabetic retinopathy(PDR)and compared to diabetic control eyes with similar diabetic retinopathy(DR)severity that did not receive anti-VEGF therapy.The morphological characteristics of IRMAs on enface OCTA imaging were graded by masked readers at baseline,then after anti-VEGF therapy in treated eyes or after observation in control eyes.Characterization of interval changes in an IRMA was based on the following parameters:branching,vessel aliber and area of adjacent capllary non-perfusion.Results:The treated group included 45 IRMA foci from 15 eyes of 11 patients,while the control group included 27 IRMA foci from 15 eyes of 14 patients.Following anti-VEGF treatment,enface OCTA demonstrated that 14 foci of IRMA(31.1%)demonstrated regression with normalization of appearance of the capillary bed,20 IRMAs(44.4%)remained unchanged,6 IRMAs(13.3%)progressed with enlargement or development of new IRMAs and 5 IRMAs(11.1%)demonstrated complete obliteration defined as IRMA disappearance with advancing capillary drop-out.In the control group,17 IRMAs(63.0%)remained stable,8 IRMAs(29.6%)progressed and 2 experienced total obliteration(7.4%).The dfference in rank order between the two groups was statistically significant(P=0.022).Conclusions:In eyes with DR status post anti-VEGF therapy,foci of IRMAs have a variable course demonstrating one of four possible outcomes:regression,stability,progression or complete obliteration.In contrast,none of the untreated control diabetic eyes demonstrated regression of IRMAs,consistent with known progression of DR severity in high risk eyes.Morphologic evaluation of IRMAs with OCTA may help to monitor changes in retinal blood flow as wellas the response to anti-VEGF treatment.