Quantification Of Vessel Density In Deep Retinal Diseases And Effect Of 11β-hydroxysteroid Dehydrogenase

Purpose:To explore the performance of deep capillary ischemia(DCI),diabetic retinopathy(DR)in 3D projection artifacts removal(PAR)optical coherence tomography(OCTA)and the effect of 11β-steroid dehydrogenase(11β-HSD)on deep retina layer of diabetic rats.Methods:(1)Patients diagnosed as DCI(acute or chronic)as well as age and sex-matched healthy subjects were enrolled in this study.All patients underwent OCTA examination and 3×3 mm~2 OCTA images focused on macula were observed without or with 3D PAR technique.Parafoveal vessel density of intermediate capillary plexus(ICP),deep capillary plexus(DCP)and deep vascular plexus(DVP)(combination of ICP and DCP)were analyzed and compared with controls.(2)Normal healthy subjects,patients with diabetes but no DR,non-proliferative DR patients,and proliferative DR patients were recruited.All patients underwent 6×6 mm~2 OCTA examination focused on macula.Parafoveal vessel density of superficial vascular plexus(SVP),intermediate capillary plexus(ICP),and deep capillary plexus(DCP)were analyzed and compared.(3)In STZ-induced diabetic rats,the expression of 11β-HSD was regulated using AAV2and sh RNA.The number of retinal GCL cells,INL thickness,and ERG a and b wave amplitudes were observed.Results:(1)Compared with the control group,the vessel density of ICP,DCP,DVP in acute and chronic DCI patients was significantly decreased(ICP:acute 40.28%vs 46.95%,P=0.006,percentage of reduction(PR)14.57%,Chronic 41.48%vs 45.50%,P=0.007,PR 8.85%;DCP:Acute 45.19%vs 49.24%,P=0.034,PR 12.17%,Chronic39.00%vs 52.03%,P=0.024,PR 15.04%;DVP:Acute 43.59%vs normal 49.92%,P=0.002,PR 12.69%;Chronic:43.50%vs 51.20%,P=0.023,PR 15.03%).There was no significant difference in ICP,DCP,and DVP in patients with acute DCI(F=0.133),nor was it chronic(F=0.121).There was no significant difference of PR in the acute and chronic phase in ICP,DCP nor DVP(ICP:P=0.934,DCP:P=0.144,DVP:P=0.735).(2)The average SVP of healthy people was 50.46%,ICP 46.88%,DCP 51.56%;SVP50.69%,ICP 44.60%,DCP 51.56%in diabetic patients without DR;NPDR patients SVP 47.15%,ICP 41.97%,DCP 43.95%,and patients with PDR SVP 45.19%,ICP37.51%,DCP 39.04%.There were significant differences between SVP,ICP,and DCP in the four groups of patients(SVP:F=12.88,P<0.01;ICP:F=54.68,P<0.01;DCP:F=129.32,P<0.01).(3)11β-HSD were expressed in rat retina.Intravitreal injection of AAV up-regulated the expression of 11β-HSD,while intravitreal injection of sh RNA down-regulated the expression of 11β-HSD.After intravitreal injection of AAV2-h HSD11B1 or sh RNA-h HSD11B2,the number of retinal GCL cells in the rat retina increased significantly(P<0.05),the thickness of the INL layer increased significantly(P<0.05),the thickness of the IPL layer increased significantly(P<0.05),and the amplitudes of a and b waves of ERG increased(P<0.05).Conclusion:3D PAR OCTA can show changes in vessel density in deep retinal capillary diseases.The vessel density of ICP and DCP in eyes with DCI were significantly decreased,but there was no significant difference in the percentage of reduction,which was consistent with DVP.With the progression of the disease,the cessel density of each layer did not change significantly.As DR increased,the retinal SVP,ICP,and DCP decreased.The significant decrease in SVP and ICP occurred during the NPDR period,and the decline in DCP occurred when the diabetic patient did not develop DR.DCP is expected to become a new indicator of the occurrence of DR.11β-HSD is expressed in the rat retina,and its expression is regulated by the gene tools AAV and sh RNA.Up-regulation of 11β-HSD1 or down-regulation of 11β-HSD2 can improve the anatomical and functional impairment of diabetic rat retina.