Therapeutic efficiency of tissue-engineered human corneal endothelium transplants on rabbit primary corneal endotheliopathy

To evaluate the therapeutic efficiency of tissue-engineered human corneal endothelia (TE-HCEs) on rabbit primary corneal endotheliopathy (PCEP),TE-HCEs reconstructed with monoclonal human corneal endothelial cells (mcHCECs) and modified denuded amniotic membranes (mdAMs) were transplanted into PCEP models of New Zealand white rabbits using penetrating keratoplasty.The TE-HCEs were examined using diverse techniques including slit-lamp biomicroscopy observation and pachymeter and tonometer measurements in vivo,and fluorescent microscopy,alizarin red staining,paraffin sectioning,scanning and transmission electron microscopy observations in vitro.The corneas of transplanted eyes maintained transparency for as long as 200 d without obvious edema or immune rejection.The corneal thickness of transplanted eyes decreased gradually after transplanting,reaching almost the thickness of normal eyes after 156 d,while the TE-HCE non-transplanted eyes were turbid and showed obvious corneal edema.The polygonal corneal endothelial cells in the transplanted area originated from the TE-HCE transplant.An intact monolayer corneal endothelium had been reconstructed with the morphology,cell density and structure similar to those of normal rabbit corneal endothelium.In conclusion,the transplanted TE-HCE can reconstruct the integrality of corneal endothelium and restore corneal transparency and thickness in PCEP rabbits.The TE-HCE functions normally as an endothelial barrier and pump and promises to be an equivalent of HCE for clinical therapy of human PCEP.

SARS-CoV-2 induced liver injury:Incidence,risk factors,impact on COVID-19 severity and prognosis in different population groups

Liver is unlikely the key organ driving mortality in coronavirus disease 2019(COVID-19)however,liver function tests(LFTs)abnormalities are widely observed mostly in moderate and severe cases.According to this review,the overall prevalence of abnormal LFTs in COVID-19 patients ranges from 2.5%to 96.8%worldwide.The geographical variability in the prevalence of underlying diseases is the determinant for the observed discrepancies between East and West.Multifactorial mechanisms are implicated in COVID-19-induced liver injury.Among them,hypercytokinemia with“bystander hepatitis”,cytokine storm syndrome with subsequent oxidative stress and endotheliopathy,hypercoagulable state and immuno-thromboinflammation are the most determinant mechanisms leading to tissue injury.Liver hypoxia may also contribute under specific conditions,while direct hepatocyte injury is an emerging mechanism.Except for initially observed severe acute respiratory distress syndrome corona virus-2(SARS-CoV-2)tropism for cholangiocytes,more recent cumulative data show SARS-CoV-2 virions within hepatocytes and sinusoidal endothelial cells using electron microscopy(EM).The best evidence for hepatocellular invasion by the virus is the identification of replicating SARS-CoV-2 RNA,S protein RNA and viral nucleocapsid protein within hepatocytes using in-situ hybridization and immunostaining with observed intrahepatic presence of SARS-CoV-2 by EM and by in-situ hybridization.New data mostly derived from imaging findings indicate possible long-term sequelae for the liver months after recovery,suggesting a post-COVID-19 persistent live injury.