Mechanisms of pulmonary endothelial barrier dysfunction in acute lung injury and acute respiratory distress syndrome

Endothelial cells(ECs)form a semi-permeable barrier between the interior space of blood vessels and the un-derlying tissues.Pulmonary endothelial barrier integrity is maintained through coordinated cellular processes involving receptors,signaling molecules,junctional complexes,and protein-regulated cytoskeletal reorganiza-tion.In acute lung injury(ALI)or its more severe form acute respiratory distress syndrome(ARDS),the loss of endothelial barrier integrity secondary to endothelial dysfunction caused by severe pulmonary inflamma-tion and/or infection leads to pulmonary edema and hypoxemia.Pro-inflammatory agonists such as histamine,thrombin,bradykinin,interleukin 1𝛽,tumor necrosis factor𝛼,vascular endothelial growth factor,angiopoietin-2,and platelet-activating factor,as well as bacterial toxins and reactive oxygen species,cause dynamic changes in cytoskeletal structure,adherens junction disorganization,and detachment of vascular endothelial cadherin(VE-cadherin)from the actin cytoskeleton,leading to an increase in endothelial permeability.Endothelial interactions with leukocytes,platelets,and coagulation enhance the inflammatory response.Moreover,inflammatory infil-tration and the associated generation of pro-inflammatory cytokines during infection cause EC death,resulting in further compromise of the structural integrity of lung endothelial barrier.Despite the use of potent antibiotics and aggressive intensive care support,the mortality of ALI is still high,because the mechanisms of pulmonary EC barrier disruption are not fully understood.In this review,we summarized recent advances in the studies of endothelial cytoskeletal reorganization,inter-endothelial junctions,endothelial inflammation,EC death,and endothelial repair in ALI and ARDS,intending to shed some light on the potential diagnostic and therapeutic targets in the clinical management of the disease.

Distributions of HLA-A and-B alleles and haplotypes in the Yi ethnic minority of Yunnan, China: relationship to other populations

Objective: To investigate the distributions of human leukocyte antigen (HLA)-A and-B alleles and HLA-A-B haplotypes in the Yi ethnic minority of the Yunnan Province, situated in southwestern China. Methods: DNA typing for HLA-A and-B loci was performed using the polymerase chain reaction-sequence-based typing (PCR-SBT) method on 114 randomly selected healthy individuals of the Yi population. The allelic frequencies of HLA-A and-B loci were calculated by direct counting and HLA-A-B haplotypes were estimated using the expectation maximization algorithm. Results: A total of 17 HLA-A and 38 HLA-B alleles were found in the Yi population. The most frequent alleles were A2402 (32.46%), A1101 (26.32%), and A0203 (10.09%) at the HLA-A locus and B4601 (12.28%), B1525 (10.09%), B4001 (8.77%), and B3802 (7.89%) at the HLA-B locus. The predominant HLA-A-B haplotypes were A2402-B1525 (7.86%) and A0203-B3802 (5.64%), followed by A1101-B4001 (4.69%). Phylogenetic analysis indicates that the Yi population in the Honghe, Yunnan Province of China basically belongs to groups of southeastern Asian origin, but shares some characteristics with northeastern Asian groups. Conclusion: The present study may add to the understanding of HLA polymorphism in the Yi ethnic group that was poorly defined previously, and provide useful information for bone marrow transplantation, anthropological research, and forensic sciences as well as for disease-association studies.