Oxygen radical generation by emigrated, intra-abdominal, and circulating PMNLs during human secondary peritonitis

[Biomarkers of system inflammation in local and diffuse peritonitis]

In cases of any acute surgical abdominal disease the progression of purulent inflammation can lead to local or diffuse peritonitis. The indicators of the degree and specificity of the inflammatory response in blood such as cytokine concentration, neutrophil activity, plasma antioxidant capacity (thiols concentration) could be considered as potential predictors of complications. The luminol-dependent chemiluminescence (CL) response of blood activated by the phorbol ester (PMA), and the concentration of cytokines IL-6, IL-8, IL-10, myeloperoxidase (MPO) and thiols in plasma were measured in patients with uncomplicated condition (group 1, n=8), local peritonitis (group 2, n=9) or diffuse peritonitis (group 3, n=9) at admission to surgery (before surgical operation, b/o), immediately after surgical operation (a/o) and a day after surgery (1 day) as well as in healthy volunteers (norm, n=12). In all time-points the cytokines and MPO concentrations measured by ELISA, in group 3 were higher than in healthy volunteers and in patients in groups 1 and 2. Blood CL demonstrated a more than 5-fold increase above the normal values in all patients, and was also higher in group 2 as compared to group 1 (b/o and a/o). Patients in group 3 had shown both maximum and minimum of CL values, which could be a consequence of neutrophil priming or exhaustion ("immune paralysis"), respectively. The same patients' plasma exhibited low thiol concentration (≤30% vs normal values). In patients with fatal outcomes (group 3, n=2) within a day after surgery, either a decrease of the CL to zero values concurrently with elevated IL-8 and IL-6 concentrations and low thiol levels was observed, or CL exceeded normal values more than 20 times with concurrent complete exhaustion of the plasma thiol pool. No clear dependency between the plasma parameters and neutrophil activity was found. Hence a parameter set for prognosis and/or early diagnosis of infectious complications in acute abdominal pathology should include different biomarkers of the inflammatory response: cytokine profile (IL-6, IL-8, IL-10), MPO and neutrophil activity, antioxidant plasma capacity (e.g., total thiols concentration).

The innate immune response to secondary peritonitis

Secondary peritonitis continues to cause high morbidity and mortality despite improvements in medical and surgical therapy. This review combines data from published literature, focusing on molecular patterns of inflammation in pathophysiology and prognosis during peritonitis. Orchestration of the innate immune response is essential. To clear the microbial infection, activation and attraction of leukocytes are essential and beneficial, just like the expression of inflammatory cytokines. Exaggeration of these inflammatory systems leads to tissue damage and organ failure. Nonsurvivors have increased proinflammation, complement activation, coagulation, and chemotaxis. In these patients, anti-inflammatory systems are decreased in blood and lungs, whereas the abdominal compartment shows decreased neutrophil activation and decreased or stationary chemokine and cytokine levels. A later down-regulation of proinflammatory mediators with concomitant overexpression of anti-inflammatory mediators leads to immunoparalysis and failure to clear residual bacterial load, resulting in the occurrence of superimposed infections. Thus, in patients with adverse outcome, the inflammatory reaction is no longer contained within the abdomen, and the inflammatory response has shifted to other compartments. For the understanding of the host response to secondary peritonitis, it is essential to realize that the defense systems presumably are expressed differently and, in part, autonomously in different compartments.

Promoter elements responsible for antioxidant regulation of MCP-1 gene expression

Monocyte chemoattractant protein-1 (MCP-1) is produced by different cells in response to inflammatory stimulation. In the present study, a series of human MCP-1 promoter reporter genes were constructed to illustrate elements involved in antioxidant dimethyl sulfoxide (DMSO) inhibition of MCP-1 gene expression. MCP-1 secretion and mRNA expression and transcription activity stimulated by TNF-alpha or IL-1beta were significantly inhibited by 1% DMSO in alveolar type II epithelial cells (A549). Deletion of -7537 to -2741 caused a 77% decrease in reporter activity, but DMSO inhibition was still present. Deletion of -7537 to -2616 containing the A1 NF-kappaB binding site resulted in a complete loss of MCP-1 stimulation. Deletion of -2585 to -74 decreased reporter activity by approximately 50%, and DMSO inhibited this induction. Deletion of -2614 to -74 containing the A2 NF-kappaB binding site completely abolished responses to stimulation. Mutations of either of the NF-kappaB binding sites decreased promoter activity, which could still be inhibited by DMSO, whereas deletion of both NF-kappaB binding sites abolished induced transcriptional activity. Mutation or deletion of the NF-kappaB binding sites significantly decreased or abolished reporter activity in response to reactive oxygen intermediates (ROI), generated by xanthine plus xanthine oxidase. In conclusion, DMSO inhibits MCP-1 gene expression through both NF-kappaB binding sites located far upstream of the 5'-flanking region of the MCP-1 promoter.

[Relaparotomy in secondary peritonitis Planned relaparotomy or relaparotomy on demand?]

Secondary peritonitis is associated with serious morbidity and a persistent high mortality in recent decades, this despite improvement in antibiotic, intensive care and surgical treatment. The available literature regarding the surgical treatment of secondary peritonitis was searched through Pubmed (1966- January 2005) as well as a hand search of references of retrieved articles. Definitions, pathophysiology and classification of secondary peritonitis are discussed, as well as the scientific rationale for the surgical treatment in secondary peritonitis. The historical development and the scientific foundation of present-day relaparotomy strategies in secondary peritonitis are evaluated, with an emphasis on two frequently applied surgical treatment strategies: planned relaparotomy and relaparotomy on demand. Criteria for relaparotomy after the initial laparotomy and potential areas for further research to reduce both morbidity and mortality are discussed. Furthermore, the care of patients with secondary peritonitis is evolving from a surgical entity to a more multidisciplinary challenge uniting surgeons, intensivists, radiologists and microbiologists. Research needs to be expanded into novel fields to further decrease morbidity and mortality.

Effects of ovariohysterectomy on canine blood neutrophil respiratory burst: a chemiluminescence study

OBJECTIVE

To examine blood neutrophil counts and luminol-enhanced chemiluminescence (CL) responses in dogs undergoing ovariohysterectomy (OH), premedicated with 2 different drugs.

STUDY DESIGN

Randomized clinical study.

ANIMALS

Forty-two healthy client-owned bitches.

METHODS

Dogs had OH under isoflurane anesthesia with either acepromazine or medetomidine, both in combination with butorphanol, administered as preanesthetic medication. Blood samples were collected when the dog was admitted, at the end of surgery, and the next day (approximately 20 hours after surgery). Blood neutrophils were counted automatically, and neutrophil oxidative activity was assessed by measuring blood CL responses (induced by opsonized zymosan and enhanced by luminol) at 37 degrees C for 40 minutes.

RESULTS

Number of circulating neutrophils was significantly increased the day after surgery reflected by enhanced blood CL responses. Neutrophil CL, however, was not significantly altered. No significant differences were detected for perioperative Polymorphonuclear neutrophil (PMN) characteristics between the 2 preanesthetic regimens.

CONCLUSIONS

In conclusion, despite clearly increasing the number of circulating neutrophils, OH did not significantly affect neutrophil respiratory burst, as measured by whole-blood CL responses.

CLINICAL RELEVANCE

Surgical operation of moderate intensity (e.g., OH) did not significantly alter one of the important immune functions, neutrophil oxidative activity. Further studies are warranted to confirm the significance of this finding, and to assess the value of following this variable in different animal patient populations.