Surgical trauma induces group II phospholipase A2 production by neutrophils at a local site after surgery

Sterile post-traumatic immunosuppression

After major trauma, the human immune system initiates a series of inflammatory events at the injury site that is later followed by suppression of local inflammation favoring the repair and remodeling of the damaged tissues. This local immune response involves complex interactions between resident cells such as macrophages and dendritic cells, soluble mediators such as cytokines and chemokines, and recruited cells such as neutrophils, monocytes and mesenchymal stromal cells. If of sufficient magnitude, these initial immune responses nevertheless have systemic consequences resulting in a state called post-traumatic immunosuppression (PTI). However, controversy exists regarding the exact immunological changes occurring in systemic compartments triggered by these local immune responses. PTI is one of the leading causes of post-surgical mortality and makes patients vulnerable to hospital-acquired infections, multiple organ failure and many other complications. In addition, hemorrhage, blood transfusion, immunesenescence and immunosuppressant drugs aggravate PTI. PTI has been intensively studied, but published results are frequently cloudy. The purpose of this review is to focus on the contributions made by different responsive modalities to immunosuppression following sterile trauma and to try to integrate these into an overall scheme of PTI.

Effects of combined application of muscle relaxants and celecoxib administration after total knee arthroplasty (TKA) on early recovery: a randomized, double-blind, controlled study

The purpose of this study was to evaluate the effectiveness of application of muscle relaxants and celecoxib in early recovery after total knee arthroplasty (TKA). One hundred and fifty patients were randomized 1:1:1 to receive either both of muscle relaxants and celecoxib or muscle relaxants alone or placebo for 2 weeks (50 patients in each group). VAS pain scores as primary efficacy, active range of motion, morphine consumption, blood loss, and postoperative complications including postoperative nausea and vomiting (PONV), extremities myasthenia and deep vein thrombosis (DVT) were determined postoperatively. Group A improved better with reduced VAS pain scores compared with another two groups. These results demonstrated that application of muscle relaxants and celecoxib into patients undergoing TKA for 2 weeks postoperative consequently improved their convalescence.

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.

Group IIA-Soluble Phospholipase A2 Levels in Patients with Infections After Esophageal Cancer Surgery

PURPOSE

To examine the changes in blood-soluble phospholipase A(2)-IIA levels caused by surgical stress and postoperative infections.

METHODS

We retrospectively analyzed a prospective database of 40 patients who underwent esophagectomy for esophageal cancer. Nine of these patients had a postoperative infection (E Inf(+) group), and 31 did not have a postoperative infection (E Inf(-) group). The blood sPLA(2)-IIA level was measured using a radioimmunoassay, and whole blood was stimulated with lipopolysaccharide (LPS) to examine the sPLA(2)-IIA production.

RESULTS

In the E Inf(-) group, the blood sPLA(2)-IIA levels peaked on postoperative day (POD) 3 then decreased gradually thereafter. Receiver-operator characteristic statistics based on the sPLA(2)-IIA values on POD 5, which are used to classify postoperative infectious complications, revealed an area under the curve of 0.789. However, stimulation of peripheral blood cells with LPS did not induce the production of sPLA(2)-IIA.

CONCLUSION

During the early postoperative phase, blood sPLA(2)-IIA levels increase according to the surgical stress. Soluble PLA(2)-IIA may be produced at the site of infection or in the liver, but not in the circulating blood. Sustained elevation of the serum sPLA(2)-IIA level, observed even after POD 3, seems to represent a response to postoperative infection.

Presence of the M-type sPLA(2) receptor on neutrophils and its role in elastase release and adhesion

Secretory phospholipase A(2) (sPLA(2)) produces lipids that stimulate polymorphonuclear neutrophils (PMNs). With the discovery of sPLA(2) receptors (sPLA(2)-R), we hypothesize that sPLA(2) stimulates PMNs through a receptor. Scatchard analysis was used to determine the presence of a sPLA(2) ligand. Lysates were probed with an antibody to the M-type sPLA(2)-R, and the immunoreactivity was localized. PMNs were treated with active and inactive (+EGTA) sPLA(2) (1-100 units of enzyme activity/ml, types IA, IB, and IIA), and elastase release and PMN adhesion were measured. PMNs incubated with inactive, FITC-linked sPLA(2)-IB, but not sPLA(2)-IA, demonstrated the presence of a sPLA(2)-R with saturation at 2.77 fM and a K(d) of 167 pM. sPLA(2)-R immunoreactivity was present at 185 kDa and localized to the membrane. Inactive sPLA(2)-IB activated p38 MAPK, and p38 MAPK inhibition attenuated elastase release. Active sPLA(2)-IA caused elastase release, but inactive type IA did not. sPLA(2)-IB stimulated elastase release independent of activity; inactive sPLA(2)-IIA partially stimulated PMNs. sPLA(2)-IB and sPLA(2)-IIA caused PMN adhesion. We conclude that PMNs contain a membrane M-type sPLA(2)-R that activates p38 MAPK.

Roles of secretory phospholipases A(2) in inflammatory diseases and trauma

Six distinct secretory small molecular weight phospholipases A(2) (PLA(2)) have been cloned and characterized from human tissues. Two of them, pancreatic group IB PLA(2) (PLA(2)-IB) and synovial-type group IIA PLA(2) (PLA(2)-IIA) have been studied as to their association to various inflammatory diseases. PLA(2)-IB is a digestive enzyme synthesized by pancreatic acinar cells. In acute pancreatitis, which is characterized by destruction of pancreatic tissue, PLA(2)-IB is released into the circulation, but its role in pancreatic and other tissue damage is still hypothetical. The concentration of PLA(2)-IIA increases in blood plasma in generalized inflammatory response resulting from infections, chronic inflammatory diseases, acute pancreatitis, trauma and surgical operations. PLA(2)-IIA is synthesized in a number of gland cells and is present in cellular secretions on mucosal surfaces including Paneth cells of intestinal mucosa, prostatic gland cells and seminal plasma, and lacrimal glands and tears. PLA(2)-IIA is expressed in hepatoma-derived cells in vitro and hepatocytes in vivo. PLA(2)-IIA is regarded as an acute phase protein and seems to function as an antibacterial agent especially effective against Gram-positive bacteria. Other putative functions in the inflammatory reaction include hydrolysis of cell membrane phospholipids and release of arachidonic acid for prostanoid synthesis.