Estimation of serum complement and its role in management of trauma

Integrated analysis of microbiome and host transcriptome reveals the damage/protective mechanism of corn oil and olive oil on the gut health of grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu)

As digestive and immune organs of animals, the gut was frequently used to evaluate the health status of aquatic animals. In previous oil source alternatives study, corn oil (CO) had been found to induce gut inflammation, while olive oil (OO) had been found to be effective in protecting intestinal health. Three diets with different oil sources (fish oil, CO, OO) were formulated for an 8-week culture experiment, and it was proposed to combine 16S sequencing and transcriptome sequencing analysis to preliminarily elucidate the damage/protection mechanism of CO and OO on the gut health of grouper (♀ Epinephelus fuscoguttatus × ♂ E. lanceolatu). We found that CO indeed damaged to gut health and destroyed the gut structure, while OO had a positive outcome in protecting the gut structure, promoting digestibility and relieving enteritis. Photobacterium, Romboutsia and Epulopiscium were significantly enriched in OO group and Staphylococcus were significantly enriched in CO group. Transcriptome sequencing further revealed CO could activated Complement and coagulation cascades, Staphylococcus aureus infection, Systemic lupus erythematosus, and Tuberculosis pathways; conversely, OO activated B-cell signaling receptors, promoted B-cell proliferation and apoptosis, and thus activated B-cell signaling pathways to enhance immunity, whereas OO can regulate IL17 signaling pathway and TNF signaling pathway to inhibit NF-κB signaling pathway to reduce pro-inflammatory response. By integrating the microbiome and transcriptome, further identified all differential microorganisms were directly and significantly correlated with differential genes, and Clostridium_sensu_stricto_1, Romboutsia, Staphylococcus might as the core regulates the expression of differential gene in the organism. These results reveal that different oil sources alter gut gene expression mainly by modulating the composition and abundance of gut microbiota, further regulating the health status of the gut. Gut microbiota could be used as biomarkers to provide reference and solutions for the mitigation of inflammation in aquatic animals.

Complement and coagulation cascades in trauma

Trauma remains a major cause of death throughout the world, especially for patients younger than 45 years. Due to rapid advances in clinical management, both in the acute and prehospital settings, trauma patients survive devastating injuries at unprecedented rates. However, these patients can often face life threatening complications that stem from the robust innate immune response induced by severe hemorrhage, leading to further tissue injury rather than repair. The complement and coagulation cascades are key mediators in this disordered reaction, which includes the development of trauma‐induced coagulopathy. There is increasing evidence that cross‐talk between these two pathways allows rapid amplification of their otherwise targeted responses and contributes to overwhelming and prolonged systemic inflammation. In this article, we summarize the initial steps of innate immune response to trauma and review the complex complement and coagulation cascades, as well as how they interact with each other. Despite progress in understanding these cascades, effective therapeutic targets have yet to be found and further research is needed both to improve survival rates as well as decrease associated morbidity.

Molecular mechanisms of inflammation and tissue injury after major trauma--is complement the "bad guy"?

Trauma represents the leading cause of death among young people in industrialized countries. Recent clinical and experimental studies have brought increasing evidence for activation of the innate immune system in contributing to the pathogenesis of trauma-induced sequelae and adverse outcome. As the "first line of defense", the complement system represents a potent effector arm of innate immunity, and has been implicated in mediating the early posttraumatic inflammatory response. Despite its generic beneficial functions, including pathogen elimination and immediate response to danger signals, complement activation may exert detrimental effects after trauma, in terms of mounting an "innocent bystander" attack on host tissue. Posttraumatic ischemia/reperfusion injuries represent the classic entity of complement-mediated tissue damage, adding to the "antigenic load" by exacerbation of local and systemic inflammation and release of toxic mediators. These pathophysiological sequelae have been shown to sustain the systemic inflammatory response syndrome after major trauma, and can ultimately contribute to remote organ injury and death. Numerous experimental models have been designed in recent years with the aim of mimicking the inflammatory reaction after trauma and to allow the testing of new pharmacological approaches, including the emergent concept of site-targeted complement inhibition. The present review provides an overview on the current understanding of the cellular and molecular mechanisms of complement activation after major trauma, with an emphasis of emerging therapeutic concepts which may provide the rationale for a "bench-to-bedside" approach in the design of future pharmacological strategies.

Role of biological modifiers regulating the immune response after trauma

Trauma induces a profound immunological dysfunction. This is characterised by an early state of hyperinflammation, followed by a phase of immunosuppression with increased susceptibility to infection and multiple organ failure. Therapeutic strategies directed at restoring immune homeostasis after traumatic injuries have largely failed in translation from "bench to bedside". The present review illustrates the role of biological modifiers of the posttraumatic immune response by portraying different modalities of therapeutic immune modulation. The emphasis is placed on anti-inflammatory (steroids) and immune-stimulatory (interferon) pharmacological strategies and modified resuscitative strategies, as well as more unconventional immunomodulatory approaches, such as immunonutrition.

Gastro-intestinal complement activation during human liver transplantation: impact on postoperative liver function

BACKGROUND

Liver transplantation elicits a systemic inflammatory response and eventually a multiple organ failure syndrome. Gastro-intestinal inflammatory activation with release of proinflammatory cytokines and complement activation may occur. This study evaluates gastro-intestinal complement activation and the association with postoperative parenchymatous liver cell injury and liver dysfunction.

METHODS

In 17 patients undergoing liver transplantation, blood samples were collected from radial artery and portal vein for analysis of complement SC5b-9 and endotoxin concentration. Portal venous-arterial SC5b-9 plasma concentration gradients at 30 min after reperfusion were calculated. Outcome parameters included postoperative organ failure and serum concentrations of aspartate aminotransferase, alanine aminotransferase, bilirubin and factor II-VII-X.

RESULTS

Patients with gastro-intestinal SC5b-9 release (n=7) had higher postoperative serum aspartate aminotransferase and alanine aminotransferase concentrations [49 (32-80) microkat/l vs 8 (6-14) microkat/l, P<0.01 and 33 (15-54) microkat/l vs 8 (4-23) microkat/l, P<0.04, respectively] and lower factor II-VII-X concentrations [46 (21-48)% vs 60 (47-69)%, P<0.02] compared to patients without gastro-intestinal SC5b-9 release (n=10). The ICU stay was prolonged in patients with gastro-intestinal complement release. There was no difference in number of organ failures and serum bilirubin concentration between the groups. The endotoxin concentration in arterial and portal vein blood was low and the association between endotoxaemia and complement activation was poor.

CONCLUSION

Gastro-intestinal complement activation may contribute to postoperative parenchymatous liver cell injury and liver dysfunction in patients undergoing liver transplantation.

Safety and efficacy of intravenous immunoglobulin prophylaxis in pediatric head trauma patients: a double-blind controlled trial

Infection is one of the major complications of severe head trauma in children. To assess whether intravenous immunoglobulin (IVIg) decreases the incidence of secondary infection after head injury in children, a randomized, double-blind trial was performed. Thirty-three children (mean age, 6.67 years; mean injury severity score, 32.8; mean Glasgow coma score, 6.1) with severe head injuries were enrolled; 1 child was excluded, 18 received IVIg, and 14 received the placebo preparation. Four hundred milligrams per kilogram of IVIg or albumin placebo was administered within 48 hours of admission. IgG levels were obtained before the infusion and then 1 week later. Patients were monitored for evidence of infection for the next 21 days. There was a 66% increase in mean IgG levels in the treatment group compared with 45% in the control group (P = .057). One death occurred in the IVIg group and two in the placebo group. No significant differences in the incidence of pneumonia, sepsis, presumed sepsis, or any other type of infection was noted. There was no difference in the number of days on mechanical ventilation or in number of hospital days. There were no side effects. It is concluded that prophylactic administration of commercial IVIg at a dose of 400 mg/kg, although safe, had no effect on the incidence of secondary infections in children with severe head injuries.