In Vitro Research Of Human Neutrophil Peptides Mediated Lung Injury

BackgroundAcute respiratory distress syndrome (ARDS) is an acute clinical sydrome characterized bysever hypoxemia which is caused by varietious of internal and external pulmonarypathogenic factors. As lack of effective treatments, it remains a major clinical challenge atthe bedside management in critically ill patients with the mortality of36%－44%. Alveolarepithelial cells and microvascular endothelial cells function as the respiratory membranewhich is responsible for the exchange of oxygen and carbon dioxide. Any abnormity ordamage of these two kinds of cells would result in the dysfunction of alveoli. Acuterespiratory distress syndrome (ARDS) is characterized with alveolar epithelial cells andmicrovascular endothelial cells injury, accompanied by an influx of neutrophils into theinterstitium and broncheoalveolar space. Increased permeability of the alveolar-capillarybarrier and subsequent lung edema and impairment of arterial oxygenation is the knottyproblem we have been trying to settle and still have to try for a long time. Activation andrecruitment of neutrophils are regarded to play a key role in progression of ARDS asneutrophils can release tons of proteinases during degranulation when activated. Humanneutrophil peptides, also known as alpha-defenses, are the dominant proteinases inneutrophils account for more5%of the totals while more than50%of primary granules.While protecting host from bacteria via membrane lysed manner by charge dependentstrength, they also induced unwanted injury to peripheral tissue through activated receptor.P2Y receptors tare a family of receptors take nucleotides as ligands for signal transduction.Purinoceptor P2Y6is a member of P2Y receptors subgroup which can selectivity increaseIL-8expression induced by HNPs and play an important role in innate immunity and immunoinflamation.ObjectiveTo explore the roles of HNPs in neutrophils mediated lung injury with an invitro model.MethodsPrimary human small airway epithelial cells (SAECs) and pulmonary microvascularendothelial cells (HPMVECs) were cultured to get fully confluent and stimulated withdifferent concentration of human neutrophil peptides (HNPs). Monolayer cells permeabilityand cell junction proteins were evaluated then. In separated experiments, MRS2578wasadded30min before HNPs treatment to block P2Y6, monolayer cells permeability and celljunction proteins were then evaluated.Results1.50μg/ml and20μg/ml HNPs dose dependently induced permeability increase in andHPMVECs, but not10μg/ml HNPs, while only50μg/ml HNPs can inducedpermeability increase in SAECs.2. HNPs induced permeability increase in HPMVECs and SAECs was mediated by P2Y6.3. HPMVECs were more sensitive to HNPs compared with SAECs.ConclusionsHNPs can induce permeability increase in HPMVECs and SAECs via P2Y6. BackgroundSepsis is a complex clinical syndrome result of the harmful and damaging host response toinfection. Respiratory infection is most common, while Gram-negative bacteria infections aremajor cases. Ealy diognosis is hard as low positive bacteria cultivation, old cases andunderlying diseases make the timely and effective treatment much more difficult. Severe sepsisis defined when sepsis progress and develop with one or much more organ dysfunction, septicshock is defined if tissue hypoprefusion emerge. Mortality of sepsis is unacceptably high as30%, and approximately50%in severe sepsis and septic shock, while incident is stillincreasing at a rate of5~10%annually, which exactly stumps ICU clinician. Systemicinflammatory response induces heterogenous dysfunctions range from thrombocytopenia todisseminated intravascular coagulation (DIC), from single organ dysfunction to multipleoragan dysfunction and to hypoperfusion. Patients with sepsis usually die of the consequentialdamage to SIRS but not of the original infection. A whole visualization and monitor ofinfection, inflammatory, consequential dysfunction can provide a clear view of the sensitivelethal factor, thus an effective and early treatment to reduce the unacceptably high mortality.ObjectiveTo analyze the sensitive prognostic factors in patients with sepsis and early evaluate the mostsensitive prognostic factor.Methods53patients with sepsis admitted to Intensive Care Unit (ICU) of the1sthospital of Guangzhoumedical university from10/17/2012to08/08/2013were enrolled in our research. Severity ofdisease was evaluated by degrees of sepsis (sepsis, severe sepsis, sepsis shock) and APAHEIIscores, respectively. Plasma samples were collected on enrollment, and concentration of IL-6and IL-8was tested with Bio-Plex200System. Clinical data including gender, age,temperature, blood pressure, Prothrombin Time (PT), Activated Partial Thromboplastin Time (APTT), Prothrombin Time Activity (PTA), concentration of D-dimer (DD), fibrinogen (Fbg),lactate and procalcitonin (PCT) were collected from the clinical records. Coagulation defectswere diagnosed according to Surviving Sepsis Campaign: International Guidelines forManagement of Severe Sepsis and Septic Shock:2012. Prognostic factors on patients’28-day-mortaliy were analyzed and the early predictors of most sensitive prognostic factorwere explored.ResultsBoth age and gender were confounding factors on patients’ prognosis. Sepsis severity,APACHEII scores, coagulation function, concentration of lactate, PCT, IL-6and IL-8hadsignificantly influence on prognosis of sepsis patients. Coagulation function and blood lactatewere independent prognostic factors, while high concentration of IL-6and IL-8were the earlypredictors of coagulation defect.ConclusionsSepsis is a heterogeneous system dysfunction, early monitor of sensitive prognostic factor isthe basis of an effective and timely treatment. Coagulation defect and its invertebility arepivotal to the paients’ prognosis, pro-inflammatory factor and chemotaatic factor provide anearly view of coagulation defect. A danamic monitor of these two factors and the coagulationdefects is still in need of a deeper study.