Excessive neutrophil activation is a major component in septic lung injury. Neutrophil-derived DNA may form extracellular traps in response to bacterial invasions. The aim of the present study was to investigate the potential role of neutrophil extracellular traps (NETs) in septic lung injury. Male C57BL/6 mice were treated with recombinant human (rh)DNAse (5 mg/kg) after cecal ligation and puncture (CLP). Extracellular DNA was stained by Sytox green, and NET formation was quantified by confocal microscopy and cell-free DNA in plasma, peritoneal cavity, and lung. Blood, peritoneal fluid, and lung tissue were harvested for analysis of neutrophil infiltration, NET levels, tissue injury, as well as CXC chemokine and cytokine formation. We observed that CLP caused increased formation of NETs in plasma, peritoneal cavity, and lung. Administration of rhDNAse not only eliminated NET formation in plasma, peritoneal cavity, and bronchoalveolar space but also reduced lung edema and tissue damage 24 h after CLP induction. Moreover, treatment with rhDNAse decreased CLP-induced formation of CXC chemokines, IL-6, and high-mobility group box 1 (HMGB1) in plasma, as well as CXC chemokines and IL-6 in the lung. In vitro, we found that neutrophil-derived NETs had the capacity to stimulate secretion of CXCL2, TNF-α, and HMGB1 from alveolar macrophages. Taken together, our findings show that NETs regulate pulmonary infiltration of neutrophils and tissue injury via formation of proinflammatory compounds in abdominal sepsis. Thus we conclude that NETs exert a proinflammatory role in septic lung injury.
Sphingomyelin (SM) metabolism in the gut may have an impact on colon cancer development. In this study, we purified alkaline sphingomyelinase (alk-SMase) from human intestinal content, and studied its location in the mucosa, expression in colon cancer, and function on colon cancer cells. The enzyme was purified by a series of chromatographies. The molecular mass of the enzyme is 60 kDa, optimal pH is 8.5, and isoelectric point is 6.6. Under optimal conditions, 1 mg of the enzyme hydrolyzed 11 mM SM per hour. The properties of the enzyme are similar to those of rat intestinal alk-SMase but not to those of bacterial neutral SMase. Immunogold electronmicroscopy identified the enzyme on the microvillar membrane in endosome-like structures and in the Golgi complexes of human enterocytes. The expression and the activity of the enzyme were decreased in parallel in human colon cancer tissues compared with the adjacent normal tissue. The enzyme inhibited DNA biosynthesis and cell proliferation dose dependently and caused a reduction of SM in HT29 cells. Intestinal alk-SMase is localized in the enterocytes, downregulated in human colon cancer, and may have antiproliferative effects on colon cancer cells. -Duan, R
The optimal administration regimens of low molecular weight heparins (LMWHs) have not yet been established. The aim of this study was to compare the efficacy and safety of 2500 and 5000 XaI units of the LMWH dalteparin in patients undergoing elective general surgery for malignant and benign abdominal disease. Prophylaxis was started in the evening before surgery and given once-daily every evening thereafter. The study was designed as a prospective, randomized, double-blind, multicentre trial. Some 66.4 per cent of patients were operated on for a malignant disorder. The primary endpoint was deep vein thrombosis (DVT) detected with the fibrinogen uptake test. Bleeding complications were recorded and classified. Analysis was made both on an intention to treat basis and in patients given correct prophylaxis (86.3 per cent). A total of 2097 patients were randomized and 27 excluded after randomization. A technically correct fibrinogen uptake test was obtained in 1957 patients. The incidence of DVT was significantly lower in patients given 5000 XaI units, this being true for both correct prophylaxis (6.8 versus 13.1 per cent, P < 0.001), on an intention to treat basis (6.6 versus 12.7 per cent, P < 0.001), and in patients with malignant disease (8.5 versus 14.9 per cent, P < 0.001). Sixty-seven patients (3.2 per cent) died within 30 days with no difference between the groups. There were two cases of fatal pulmonary embolism. The frequency of bleeding complications in the whole series was higher in patients randomized to 5000 XaI units (4.7 versus 2.7 per cent, P = 0.02), although this was not the case in those operated on for malignant disease (4.6 versus 3.6 per cent, P not significant). Dalteparin in the dose of 5000 XaI units started in the evening before surgery has a good thromboprophylactic effect in high-risk general surgery at the cost of a small bleeding risk. In patients with malignant disease there was no increased risk of bleeding. The overall frequency of fatal pulmonary embolism with dalteparin is extremely low, even in this high-risk group of patients.
This study indicates high morbidity associated with defunctioning loop ileostomy. Our data suggest that the stoma time should be limited to reduce complications. Monitoring and early stoma reversal should be considered in elderly patients. Furthermore, stoma reversal is not uneventful, and more studies are needed to address how to minimize complications.
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