Complement inhibition alleviates paraquat-induced acute lung injury.

The widely used herbicide, paraquat (PQ), is highly toxic and claims thousands of lives from both accidental and voluntary ingestion. The pathological mechanisms of PQ poisoning-induced acute lung injury (ALI) are not well understood, and the role of complement in PQ-induced ALI has not been elucidated. We developed and characterized a mouse model of PQ-induced ALI and studied the role of complement in the pathogenesis of PQ poisoning. Intraperitoneal administration of PQ caused dose- and time-dependent lung damage and mortality, with associated inflammatory response. Within 24 hours of PQ-induced ALI, there was significantly increased expression of the complement proteins, C1q and C3, in the lung. Expression of the anaphylatoxin receptors, C3aR and C5aR, was also increased. Compared with wild-type mice, C3-deficient mice survived significantly longer and displayed significantly reduced lung inflammation and pathology after PQ treatment. Similar reductions in PQ-induced inflammation, pathology, and mortality were recorded in mice treated with the C3 inhibitors, CR2-Crry, and alternative pathway specific CR2-fH. A similar therapeutic effect was also observed by treatment with either C3a receptor antagonist or a blocking C5a receptor monoclonal antibody. Together, these studies indicate that PQ-induced ALI is mediated through receptor signaling by the C3a and C5a complement activation products that are generated via the alternative complement pathway, and that complement inhibition may be an effective clinical intervention for postexposure treatment of PQ-induced ALI.

Pulse oximetry waveform: A non-invasive physiological predictor for the return of spontaneous circulation in cardiac arrest patients ---- A multicenter, prospective observational study.

OBJECTIVE: This study aimed to investigate the predictive value of pulse oximetry plethysmography (POP) for the return of spontaneous circulation (ROSC) in cardiac arrest (CA) patients. METHODS: This was a multicenter, observational, prospective cohort study of patients hospitalized with cardiac arrest at 14 teaching hospitals cross China from December 2013 through November 2014. The study endpoint was ROSC, defined as the restoration of a palpable pulse and an autonomous cardiac rhythm lasting for at least 20 minutes after the completion or cessation of CPR. RESULTS: 150 out-of-hospital cardiac arrest (OHCA) patients and 291 in-hospital cardiac arrest (IHCA) patients were enrolled prospectively. ROSC was achieved in 20 (13.3%) and 64 (22.0%) patients in these cohorts, respectively. In patients with complete end-tidal carbon dioxide (ETCO2) and POP data, patients with ROSC had significantly higher levels of POP area under the curve (AUCp), wave amplitude (Amp) and ETCO2 level during CPR than those without ROSC (all p < 0.05). Pairwise comparison of receiver operating characteristic (ROC) curve analysis indicated no significant difference was observed between ETCO2 and Amp (p = 0.204) or AUCp (p = 0.588) during the first two minutes of resuscitation. CONCLUSION: POP may be a novel and effective method for predicting ROSC during resuscitation, with a prognostic value similar to ETCO2 at early stage.