Background The vitreoretinal traction plays a critical role in the formation of macular hole and cystoid macular edema.Enzymatic vitreolysis has potential in relieving vitreoretinal traction as a simple and less invasive method in comparison with pars plane vitrectomy.ObjectiveThis study is to investigate the effects of plasmin mutant with kringle domains deficiency(Plm△K)on vitreoretinal interface in new Zealand white rabbits.Methods Plm△K was prepared through activating plasminogen mutant with Kringle domains deficiency (Plg△K) by tissue plasminogen activator (tPA).100μL of Plm△K at the dose of 0.5,1.0 and 1.5μmol/min was injected respectively into the vitreous of 48 New Zealand white rabbits and 16 eyes for each dose.B-scan and optical coherence tomography (OCT) were performed to detect the structure variety at the vitreoretinal interface in 1 day and 7 days after injection.The gross anatomy analysis with triamcinolone acetonide fine particle suspension,as well as histopathological examinations by scanning electron microscopy,was performed in the different time points mentioned above.Results Two peptide chains were determined with the relative molecular weight about 26000 and 5000 by the gel imaging analysis of reduced SDS-PAGE.Separation of the posterior vitreous cortex from retina was found after intravitreous injection under the B-scan and OCT.The ultrastructure change of vitreoretinal interface as well as the examination of fine particle suspension by triamcinolone acetonide demonstrated the same outcome.The degree of remnants of vitreous cortex showed the negative correlation with the dosage of Plm△K (r=-0.9516,P=0.048).No significant correlation was found between the degree of remnants of vitreous cortex and the action time(r=-0.720,P=0.470).There was no obvious morphological difference in outer layer of retina between control eyes and Plm△K-treated eyes.No drug-related adverse event was found after intravitreous injection of Plm△K.Conclusion Intravitreous injection of Plm△K alone can induce complete separation of vitreous from retina.This procedure is safe and effective.

Background Retinal vein occlusion is a common retinal vascular diseases.Thromblysis and anticoagulation therapies are main approaches.However,systemic thrombolysis is relatively inefficient,and it often enhances the risk of hemorrhage.Objective This study was to investigate the therapeutic effects of PLM-ΔK,a kringle deficiency mutant of plasmin,on photochemically induced branch retinal vein occlusion (BRVO) after intravitreal injection.Methods BRVO models were established by the combination of caudal vein injection of Rose Bengal with argon laser radiation of periphery area of retinal veins in SD rats.Forty model rats were randomized into balance salt solution (BSS) group and 0.01 U,0.02 U,0.03 U PLM-ΔK group,and 10 μl corresponding drug was intravtreally injected 12 hours after modeling.Ophthalmoscopy and fundus fluorescein angiography (FFA) were performed to observe the change of retinal veins.The animals were sacrificed 3 days after intravitreal injection,and hematoxylin and eosin staining was used for the histopathological and ultrastructural examination of retinas.The retina of the rats was isolated for the stretched preparation of retina.The expressions of fibronectin (FN) and laminin (LN) in eyeball wall were assayed by immunofluorescence technology.The use and care of the animals complied with Statement of the Association for Research in Vision and Ophthalmology.Results The revascularization of over 2 retinal veins was found in 0,3,6 and 8 rats in the BBS group and 0.01 U,0.02 U,0.03 U PLM-ΔK group 3 days after intravitreal injection,respectively,showing a significant difference among the groups (x2=9.635,P =0.022),and the rat number with revascularization in 0.01 U PLM-ΔK group was not significantly different from that in BSS group (Z=-1.558,P =0.119),but the difference between 0.03 U PLM-ΔK group and 0.01 U PLM-ΔK group was significant (Z=-2.762,P=0.006).In the third day after intravitreal injection,retinal vein thrombus were found in the BSS group under the light microscope,and angiogenesis was seen on the retinal flatmount nuclear.In the 0.03 U PLM-ΔK group,posterior vitreal detachment was exhibited under the light microcope,and no retinal new vessel and cell damage were seen.FN was strongly expressed in the inner limiting membrane (ILM) layer,photocyte layer,outer limiting membrane (OLM) layer,choroid and scleral layer,and LN was expressed mainly in the ILM,OLM and scleral layer in the BSS group.However,the expression intensities of FN and LN were obviously weakened in the 0.03 U PLM-ΔK group.Conclusions Intravitreal injection of PLM-ΔK can enhance the reperfusion of occluded branch retinal vein and serve as a potential therapeutic drug for BRVO.Also it can permeate into choroid after intravitreal injection to degradate FN and LN.

AIM: Endothelial progenitor cells(EPCs) are a group of stem cells/progenitor cells,which exist in postnatal body and can be of specially homing to the foci of angiogenesis and then differentiate into endothelial cells.This investigation was to study the method for culturing endothelia progenitor cells(EPCs) in vitro,and to observe its feasibility and condition formed vessel-like structure.METHODS: The cells were isolated from born marrow,peripheral blood,umbilical cord blood or spleen in different laboratories.The EPCs derived from human umbilical cord blood and rabbit peripheral blood were cultured in vitro through adhesion selection and were differentiated into endothelial cells under the induction of special cytokines.The expression of CD34,VEGFR-2,AC133 and VE-cadherin were detected by fluorescence-activated cell sorting.The endothelial cell lineage was confirmed by DiI-ac-LDL up-taking and Ⅷ factor immunocytochemistry.RESULTS: The EPCs derived from human umbilical cord blood and rabbit peripheral blood were cultured in vitro successfully,forming cord-like and tube-like structure.The EPCs derived from rabbit peripheral blood differentiated more mature and formed vessel-like structure.CONCLUSION: The EPCs derived from human umbilical cord blood and rabbit peripheral blood formed vessel-like structure in vitro.EPCs may be a potential resource of vessel tissue engineering.

Objective:To explore the clinical and genetic characteristics of two children with mental retardation and microcephaly.Methods:Two children who had visited the Anhui Children′s Hospital respectively on March 12 and June 22, 2021 were selected as the study subjects. Peripheral venous blood samples were collected from them and their parents, and subjected to chromosomal karyotyping and whole exome sequencing analyses. Candidate variants were verified by Sanger sequencing and pathogenicity analysis. This study was approved by the Anhui Children′s Hospital (Ethics No. EYLL-2018-008).Results:Chromosomal karyotyping and copy number detection of the two children had found no abnormality. Whole exome sequencing revealed that child 1 has harbored a c. 471delT (p.Pro157Profs*9) frameshifting variant of the CASK gene, whilst child 2 has harbored a c. 1259_1269delCTGAGAATAAC (p.Pro420fs*27) frameshifting variant of the CASK gene. Sanger sequencing confirmed that both variants were de novo in origin. Based on the guidelines from the American College of Medical Genetics and Genomics and the Association for Molecular Pathology (ACMG-AMP), both variants were rated as pathogenic (PVS1+ PS2+ PP3). Conclusion:The de novo variants of the CASK gene probably underlay the pathogenesis of mental retardation and microcephaly in both children.