Expression of Toll-like receptors 2 and 4 is downregulated after operation

Expression of Toll-like receptors 2 and 4 on peripheral mononuclear cells (PBMCs) after laparoscopic cholecystectomy

Increasing evidence suggests that the course and intensity of inflammation, as well as repair processes, developed in response to stress, injury, and trauma, depend on the interaction between immediately released endogenous molecules, called alarmins or danger/damage-associated molecular patterns (DAMPs) and cellular pattern recognition receptors (PRR) including Toll-like receptors (TLRs) and activation of inflammatory/immune cells. Therefore, the aim of this study was to examine the expression of TLRs in peripheral blood mononuclear cells (PBMCs), CD3⁺, and CD14⁺ cells in control group and in patients before the laparoscopic cholecystectomy, and three and seven days after surgery. Flow cytometry was used to evaluate expression of TLR2 and TLR4. TLR2 and especially TLR4 expression levels on PBMCs were significantly lower in patients with asymptomatic cholelithiasis than in the control group. Laparoscopic surgery did not induce the significant changes in the expression of TLR2, both on PBMCs and CD3⁺ and CD14⁺ cell subpopulations. On the contrary, TLR4 expression level on PBMCs was significantly lower on the third and seventh postoperative day than before surgery. Collectively, the expression levels of cellular TLRs, and especially TLR2 and TLR4, might strongly influence the responsiveness of cells to DAMP activation, and in this way can regulate the intensity of inflammatory response to surgical injury.

Burn injury is associated with an infiltration of the wound site with myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) have been identified in the burn wound, however their characterization is incomplete. To study this, mice were subjected to a major burn and skin cells were isolated 3 days thereafter for analysis. Significant infiltration of the burn wound with MDSCs was observed as compared with uninjured skin. The skin of naïve mice did not contain MDSCs. Characterization of the cells showed that 33% of MDSCs in the wound were monocytic (M)-MDSCs, which was significantly less than that found in uninjured skin (52%). In contrast, polymorphonuclear (PMN)-MDSCs were greater in the burn wound as compared with uninjured skin. Burn wound TLR expression by both MDSCs subsets was decreased as compared with uninjured skin. Wound MDSCs produced pro- and anti-inflammatory cytokines and iNOS was present in both MDSC subsets, whereas ARG1 was only present in M-MDSCs. In conclusion, both M- and PMN-MDSCs infiltrate burn wound with after injury, however, they displayed decreased TLR expression, suggesting receptor down-regulation.

RNA expression preoperatively and postoperatively following total knee replacement: a pilot study in patients with and without chronic postsurgical pain

BACKGROUND AND OBJECTIVE

Differences in gene expression may provide insight into the biological pathways involved in chronic postsurgical pain (CPSP). We compared blood RNA microarrays preoperatively and postoperatively following total knee arthroplasty (TKA) in patients with and without CPSP.

METHODS

Patients scheduled for primary TKA had whole blood samples obtained preoperatively and at 48 hours and 6 months postsurgery. RNA expression (54 613 transcripts) were assayed using the "Affymetrix HG-U133 plus 2.0" microarray. Genes that met the threshold criteria of ±1.5-fold differential change in expression (CPSP vs non-CPSP), with p<0.0125, were considered for pathway analysis. WikiPathways was used to identify biological pathways that were affected (p<0.01) by differentially regulated genes.

RESULTS

Four of 16 (25%) patients had CPSP at 6 months. Preoperatively, 325 (0.6%) genes met the criteria, with 292 (89.9%) having greater expression in the CPSP group. Twelve biological pathways were affected, with the mitogen-activated kinase, phosphatidylinositide 3-kinase-protein kinase B-mammalian target of rapamycin, and brain-derived neurotrophic factor signaling pathways having known association with pain. At 48 hours, 26 genes met the criteria; 7 pathways were affected, including transforming growth factor-β with known association with pain. At 6 months 55 genes met the criteria, with 49 increased in the CPSP group. Four biological pathways were affected, with only the chemokine signaling pathway having known association with pain.

CONCLUSIONS

Despite a lack of clinical differences, patients who develop CPSP have upregulated pain pathways preoperatively; however, only the chemokine pathway remained differentially upregulated at 6 months postsurgery.

Toll-like receptors: Significance, ligands, signaling pathways, and functions in mammals

This review attempts to cover the implication of the toll-like receptors (TLRs) in controlling immune functions with emphasis on their significance, function, regulation and expression patterns. The tripartite TLRs are type I integral transmembrane receptors that are involved in recognition and conveying of pathogens to the immune system. These paralogs are located on cell surfaces or within endosomes. The TLRs are found to be functionally involved in the recognition of self and non-self-antigens, maturation of DCs and initiation of antigen-specific adaptive immune responses as they bridge the innate and adaptive immunity. Interestingly, they also have a significant role in immunotherapy and vaccination. Signals generated by TLRs are transduced through NFκB signaling and MAP kinases pathway to recruit pro-inflammatory cytokines and co-stimulatory molecules, which promote inflammatory responses. The excess production of these cytokines leads to grave systemic disorders like tumor growth and autoimmune disorders. Hence, regulation of the TLR signaling pathway is necessary to keep the host system safe. Many molecules like LPS, SOCS1, IRAK1, NFκB, and TRAF3 are involved in modulating the TLR pathways to induce appropriate response. Though quantification of these TLRs helps in correlating the magnitude of immune response exhibited by the animal, there are several internal, external, genetic and animal factors that affect their expression patterns. So it can be concluded that any identification based on those expression profiles may lead to improper diagnosis during certain conditions.

Characterization of Toll-like receptor-4 (TLR-4) in the spleen and thymus of Swiss albino mice and its modulation in experimental endotoxemia

Expression of innate immune receptors varies among organs and species and within different strains among the same species; thus, periodic classification of different pattern recognition receptors in the available strains is necessary to initiate different therapeutic approaches to combat inflammation. On characterization of TLR-4 in spleen and thymus of Swiss albino mice—with no reports of TLR-4 expression—induced with endotoxemia, it was found that the mode of expression varied among the organs at both mRNA and protein level in a time-dependent manner. Their functionality was verified by measuring proinflammatory and anti-inflammatory cytokines. In the in vitro study using isolated macrophages and lymphocytes from the same organs, the expression of TLR-4 after a shorter period of LPS stimulation was verified. The results substantiated the potent role of macrophage on LPS challenge compared to lymphocytes. The diverse pattern of TLR-4 expression on different cell population indicated their distinct functional activity in LPS-endotoxemia. It may be hypothesized that the expression patterns of TLR-4 could be different based on the anatomical localization and the varying bacterial milieu or bacterial endotoxin encountered in each anatomical location. Thus, blocking TLR-4 or administering IL-6 or IL-10 might impart protection against endotoxemia in the clinical field.

Genetic polymorphisms of innate and adaptive immunity as predictors of outcome in critically ill patients

Sepsis and septic shock frequently cause the admission or complicate the clinical course of critically ill patients admitted in the intensive care units (ICU). Genetic variations disrupting the immune sensing of infectious organisms, could affect the ability of the immune system to respond to infection, and may influence both the genetic predisposition to infection and the diversity of the clinical presentation of sepsis. The aim of this study was to uncover possible associations between common functional immune gene polymorphisms (of both innate and adaptive immunity) and ICU-acquired sepsis and mortality. The TLR4-D299G (rs4986790), TLR4-T399I (rs4986791), C2-c.841_849+19del28 (rs9332736), TACI-C104R (rs34557412), BAFFR-P21R (rs77874543), and BAFFR-H159Y (rs61756766) polymorphisms were detected in a cohort of 215 critically ill patients, admitted in an 8-bed medical/surgical ICU. Interestingly, TLR4-D299G, TLR4-T399I and BAFFR-P21R carriage was associated with a lower risk of ICU-acquired sepsis. This association applied particularly in medical patients, while in trauma and surgical patients no significant associations were observed. Moreover, carriers of TACI-C104R displayed an undiagnosed mild to moderate hypogammaglobulinemia along with a significantly lower survival rate in the ICU, although lethal events were not attributed to sepsis. These findings further elucidate the role that host immune genetic variations may play in the susceptibility to ICU-acquired sepsis and ICU mortality.

Immune response after laparoscopic colectomy for cancer: a review

Background and aim: Colorectal cancer (CRC) is the third leading cause of cancer mortality worldwide and laparoscopic colectomy has been established as equivalent to the open approach in terms of oncological results and patients’ safety. Survival benefits have been reported in favor of laparoscopic colectomy (LC) in stage III CRC patients. Different immune responses after surgery, in terms of innate and cellular immunity, may potentially explain some of the reported differences. This review summarizes the literature on differences in immune response after the laparoscopic and the open approach for CRC.

Materials and Methods: A literature search of electronic databases was conducted and all studies published on ‘colorectal cancer’, ‘laparoscopic and open colectomy’ ‘immune response’ and ‘surgical stress laparoscopy versus open’ were collected. Among these, the ones referring to CRC and those that had any clinical relevance offering information on perioperative parameters were used.

Results: Despite the heterogeneity of studies, they support the view that innate immune response is activated to a greater degree in open colectomy (OC), which may be related to the more extensive trauma and surgical stress. On the other hand, cellular immunity is better preserved after LC. These differences are more pronounced in the immediate postoperative period.

Conclusions: LC has been related to decreased up-regulation of innate immunity and better-preserved cellular immunity. The latter may be related to better anti-tumor activity and may be beneficial in terms of oncological survival in a subgroup of LC patients.

Up-regulation of Toll-like receptors 2 and 4 on peripheral monocytes after major abdominal surgical operation

BACKGROUND

This study is to investigate the time-course expression of TLR2 and TLR4 on peripheral monocytes in patients receiving major abdominal surgical operation.

METHODS

Blood samples were obtained from peripheral vein before and after an operation in 30 patients with gastrointestinal or pancreatic surgery. The mRNA expression of TLR2, TLR4, TNF-α and IL-6 on peripheral blood mononuclear cells (PBMC) was analyzed by real-time PCR. The expressions of TLR2, TLR4, HLA-DR, CD80, and CD86 on monocytes were analyzed by flow cytometry. The expressions of TLR2 and TLR4 on monocytes responding to each agonist (zymosan and lipopolysaccharide) were also measured by flow cytometry.

RESULTS

TLR2 and TLR4 mRNA showed significant up-regulation after the completion of the operation when compared with those before the operation. TLR2 expression reached its peak level on day 1 and TLR4 on days 1 and 3. There was no significant difference between pre- and post-operation in the expressions of HLA-DR, CD80 and CD86. Stimulation with zymosan, increased the expression of TLR2 significantly after the operation and reached its highest value on day 3. Similarly, after stimulation with lipopolysaccharide, the expression of TLR4 was also increased and the highest level was observed on day 1. The expression of TNF-α and IL-6 mRNA decreased after completion of the operation and gradually returned to basal level.

CONCLUSIONS

The expressions of TLR2 and TLR4 on monocytes were up-regulated during the early period after a major abdominal surgical operation in patients, which might be related to the activation of innate immunity.

Long-lasting effect of infant rats endotoxemia on heat shock protein 60 in the pancreatic acinar cells: involvement of toll-like receptor 4

Introduction. Lipopolysaccharide endotoxin (LPS) is responsible for septic shock and multiorgan failure, but pretreatment of rats with low doses of LPS reduced pancreatic acute damage. Aim. We investigated the effects of the endotoxemia induced in the early period of life on Toll-like receptor 4 (TLR4), heat shock protein 60 (HSP60) and proapoptotic Bax, caspase-9 and -3 or antiapoptotic Bcl-2 protein expression in the pancreatic acinar cells of adult animals. Material and Methods. Newborn rats (25 g) were injected with endotoxin (Escherichia coli) for 5 consecutive days. Two months later, pancreatic acinar cells were isolated from all groups of animals and subjected to caerulein stimulation (10⁻⁸ M). Protein expression was assessed employing Western blot. For detection of apoptosis we have employed DNA fragmentation ladder assay. Results. Preconditioning of newborn rats with LPS increased TLR4, Caspase-9 and -3 levels, but failed to affect basal expression of HSP60, Bax, and Bcl-2. Subsequent caerulein stimulation increased TLR4, Bcl-2, and caspases, but diminished HSP60 and Bax proteins in pancreatic acinar cells. Endotoxemia dose-dependently increased TLR4, Bax, HSP60, and both caspases protein signals in the pancreatic acini, further inhibiting antiapoptotic Bcl-2. Conclusions. Endotoxemia promoted the induction of HSP60 via TLR4 in the infant rats and participated in the LPS-dependent pancreatic tissue protection against acute damage.

Toll-like receptors in the inflammatory response during open and laparoscopic colectomy for colorectal cancer

BACKGROUND

Surgical interventions activate a cascade of reactions that result in an aseptic inflammatory reaction. This inflammatory response initiates the organism's innate immunity. Laparoscopic surgery reduces the trauma, and patients benefit from diminished surgical trauma and maintained immune function. Cytokine levels and C-reactive protein (CRP) are related to the magnitude of surgical trauma and surgical stress. Toll-like receptors (TLRs) 2 and 4 are the first sensor-recognition receptors of the invading pathogens for the innate immune response. This study aimed to compare the inflammatory response and then the stress response during laparoscopic and open colectomy for cancer by calculating TLR-2 and TLR-4 as the first sensor-recognition receptors together with interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and high-sensitivity CRP (hsCRP).

METHODS

A total 40 patients with colorectal cancer were randomized in two groups: group A (open colectomy, n = 20) and group B (laparoscopic colectomy, n = 20). An epidural catheter was placed in all patients 1 h preoperatively. Rupivocaine was administered perioperatively and 48 h postoperatively. Blood samples were taken for calculation of IL-6, TNF-α, hsCRP, TLR-2, and TLR-4 preoperatively and 5 min after deflation of pneumoperitoneum (group B) or 5 min after division of the colon (group A), then 6 and 24 h postoperatively.

RESULTS

The mean operative time was 115 for group A and 142 min for group B. The mean blood loss was respectively 240 and 105 ml (P < 0.001), and the mean hospital stay was respectively 8 and 5 days (P < 0.05). The IL-6 level was significant higher in group A than in group B at 6 and 24 h postoperatively (P < 0.0001), and the hsCRP level was significant higher in group A than in group B at 24 h postoperatively (P < 0.001). The TNF-α values did not differ between the two groups. The TLR-2 level was significantly higher in group A than in group B at 5 min (P = 0.013) and 24 h (P = 0.007) postoperatively. The TLR-4 level was significant higher in group A than in group B at 5 min postoperatively (P = 0.03).

CONCLUSION

The inflammatory response and the resultant stress response are significantly less during laparoscopic colectomy than during open colectomy for colorectal cancer. This is an obvious short-term clinical benefit for the patient, providing tinder for further study to investigate the long-term results of laparoscopic colectomy versus open colectomy for colorectal cancer.

Propolis immunomodulatory activity on TLR-2 and TLR-4 expression by chronically stressed mice

Our group has been investigating the immunomodulatory activity of propolis in stressed mice. In this work, we wish to report the action of propolis in chronically stressed mice, assessing the Toll-like receptor (TLR-2 and TLR-4) expression by spleen cells and corticosterone levels as a stress indicator. Male C57BL/6 mice were divided into four groups: G1 was considered the control; G2 was treated with propolis (200 mg kg(-1)); G3 was submitted to restraint stress for 14 days; and G4 was treated with propolis and immediately submitted to stress. After sacrifice, spleens were removed and TLR-2 and TLR-4 gene expression was analysed. TLR-2 and TLR-4 expression was increased in propolis-treated mice, and propolis administration to stressed mice prevented the inhibition of TLR-2 and TLR-4 expression. No differences were seen in the corticosterone levels among the groups. Propolis exerted an immunomodulatory action in chronically stressed mice, upregulating TLR-2 and TLR-4 mRNA expression, contributing to the recognition of microorganisms and favouring the initial steps of the immune response during stress.

Severe gunshot injuries in a porcine model: impact on central markers of innate immunity

BACKGROUND

the mechanisms behind lipopolysaccharide (LPS) tolerance remain obscure. LPS signals through Toll-like receptor 4 (TLR4) and severe trauma/haemorrhage may influence binding and signalling through this receptor, e.g. by changing membrane expression or by releasing endogenous ligands like High Mobility Group Box 1 (HMGB1). The aim of this study was to examine these relations further in a porcine model with standardized trauma.

METHODS

nine anaesthetized pigs sustained one gunshot through the femur and one pistol shot through the upper abdomen. Blood was sampled before and 90 min after shooting. The samples were stimulated for 4 h with LPS 10 ng/ml or an equivalent amount of normal saline. The leucocyte response was evaluated by measuring the tumour necrosis factor-α (TNF-α) and CXC ligand 8 (CXCL8) in the supernatant. Flow cytometry was used to measure the surface expression of TLR4 on CD14+ monocytes. HMGB1 concentrations were measured in the plasma.

RESULTS

trauma and treatment caused a significant decline in the LPS-stimulated concentrations of TNF-α [4.53 ± 0.24 pg/ml (ln) at 0 min, 3.54 ± 0.35 pg/ml (ln) at 90 min, P=0.026], but did not modify the release of CXCL8. Monocyte TLR4 expression was unchanged. Plasma HMGB1 increased significantly [<0.92 vs. 3.02 ± 0.19 ng/ml (ln), P<0.001]. The concentrations of TNF-α and CXCL8 did not correlate with TLR4 expression or HMGB1 concentrations.

CONCLUSION

the results suggest that trauma-induced LPS tolerance is not primarily regulated by TLR4 expression on circulating CD14+ monocytes or by the release of HMGB1 from damaged tissues.

Effect of major abdominal surgery on the host immune response to infection

PURPOSE OF REVIEW

The present review summarizes key studies on the effects of major abdominal surgery on the host response to infection published during the last 18 months.

RECENT FINDINGS

Surgical trauma causes stereotyped systemic proinflammatory and compensatory anti-inflammatory reactions. It is leukocyte reprogramming rather than general immune suppression. The list of recent findings is long. Preoperative infectious challenge was found to increase survival. Obesity is associated with increased production of interleukin-17A in peritonitis. Abdominal surgery alters expression of toll-like receptors (TLRs). The acute phase reaction down-regulates the transcription factor carbohydrate response element binding protein. Myosin light chain kinase activation is a final pathway of acute tight junction regulation of gut barrier and zonula occludens 1 protein is an essential effector. The brain is involved in regulating the immune and gut system. Elimination of lipopolysaccharide is challenging. Th1/Th2 ratio is lowered in patients with postoperative complications. Cholinergic anti-inflammatory pathways can inhibit tissue damage. The new substance PXL01 prevents adhesions. Postoperative infection causes incisional hernias. Hypothermia reduced human leukocyte antigen DR surface expression and delayed tumor necrosis factor clearance. Systems biology identified interferon regulatory factor 3 as the negative regulator of TLR signaling. Protective immunity could contribute defeating surgical infections.

SUMMARY

Systemic inflammation is the usual response to trauma. All organs seem to be involved and linked up in cybernetic systems aiming at reconstitution of homeostasis. Although knowledge is still fragmentary, it is already difficult to integrate known facts and new technologies are required for information processing. Defining criteria to develop therapeutic strategies requires much more insight into molecular mechanisms and cybernetics of organ systems.

Propolis effects on pro-inflammatory cytokine production and Toll-like receptor 2 and 4 expression in stressed mice

INTRODUCTION

Propolis is a beehive product and its immunomodulatory action has been well documented; however, little is known concerning its activity on the immune system of stressed mice. This work investigated a possible role of propolis against the immunosuppressive effects induced by stress in mice, assessing the pro-inflammatory cytokine (IL-1beta and IL-6) production and Toll-like receptor (TLR-2 and TLR-4) expression by spleen cells.

METHODS

BALB/c mice were divided into 3 groups: G1 was considered control; G2 was submitted to restraint stress for 3 days, and G3 was treated with propolis and immediately submitted to stress. After sacrifice, spleens were removed and TLR-2 and TLR-4 gene expression was analyzed, as well as the pro-inflammatory cytokine production. Serum corticosterone levels were determined by radioimmunoassay as a stress indicator.

RESULTS

Stressed mice, treated or not with propolis, produced higher corticosterone levels, whereas IL-1beta and IL-6 production was inhibited. TLR-2 and TLR-4 expression was inhibited in stressed mice, while propolis exerted an immunorestorative role in TLR-4 expression. The immunosuppressive effects on IL-1beta and IL-6 production and on TLR expression by stressed mice might have occurred due to a higher corticosterone production during stress.

CONCLUSION

Propolis treatment did not antagonize the inhibitory effects on pro-inflammatory cytokine production, however it restored at least partially TLR2 mRNA expression and counteracted the inhibition on TLR-4 expression in stressed animals, contributing to the recognition of microorganisms during stressful conditions.

Electroacupuncture downregulates TLR2/4 and pro-inflammatory cytokine expression after surgical trauma stress without adrenal glands involvement

Cumulative evidences suggest that electroacupuncture (EA) can modulate immune function, but the mechanism needs further study. In the present study, the contribution of EA on toll-like receptors 2 and 4 (TLR2/TLR4) and pro-inflammatory cytokine expression after surgical trauma stress were investigated. The mRNA level of both TLR2/4 and pro-inflammatory cytokine was measured by quantitative real-time PCR. ELISA and Western blot assay were chosen for TLR2/TLR4 protein expression and pro-inflammatory cytokine production, respectively. The results showed that surgical trauma stress increased TLR2 mRNA and TLR2/4 proteins in the spleen and augmented pro-inflammatory cytokines (e.g. IL-1beta) mRNA and protein expression in the spleen and plasma. These effects could be deteriorated by adrenalectomy (ADX). EA at "Zusanli" acupoint significantly inhibited surgical trauma-induced TLR2 mRNA and TLR2/4 protein expression in spleen and pro-inflammatory cytokine expression in the spleen and plasma. ADX, however, could not block the effect of EA. These results suggested that surgical trauma stress primes the innate immune system for enhanced TLR2 expression and pro-inflammatory cytokine production. EA inhibits TLR2/4 and pro-inflammatory cytokines to produce an anti-inflammatory effect in a surgical trauma stress model, without adrenal gland involvement.

Major hepatectomy induces phenotypic changes in circulating dendritic cells and monocytes

INTRODUCTION

Patients undergoing major hepatectomy are at increased risk for post-operative morbidity and mortality, and changes in the phenotype of effector cells may predispose these patients to infectious sequelae.

METHODS

To better understand post-hepatectomy immune responses, peripheral blood from 15 hepatectomy patients was drawn immediately before and after liver resection and on post-operative days 1, 3, and 5. Circulating monocytes and dendritic cells were analyzed by flow cytometry for quantity, phenotype, activation status, human leukocyte antigen DR (HLA-DR) expression, and toll-like receptor-2 and -4 expression.

RESULTS

Major hepatectomy increased the numbers of activated CD16(bright) blood monocytes and the percentage of activated dendritic cells, although monocyte HLA-DR expression was reduced. These results may represent both dysfunctional antigen presentation and pending anergy, as well as cellular priming of immune effector cells. Better understanding of the alterations in innate immunity induced by hepatectomy may identify strategies to reduce infectious outcomes.

Expression of Toll-like receptors 2 and 4 on innate immunity cells modulated by cardiac surgical operation

OBJECTIVE

This study aimed to follow-up on the changes in the expression of Toll-like receptors (TLRs) on monocytes and granulocytes in venous blood of patients undergoing cardiac surgical operation.

MATERIAL AND METHODS

TLR2 and TLR4 expression on blood cells was determined by flow cytometry in 40 patients undergoing cardiac surgery performed either with cardiopulmonary bypass (CPB) ("on-pump") or without it ("off-pump").

RESULTS

Intensity of the expression of TLR2 on both monocytes and granulocytes, expressed as median fluorescence intensity, is significantly reduced during CPB, being lower in both groups at the finish of surgery. These changes are not so remarkable in the case of TLR4 expression. Compared to "on-pump" patients, there is a higher relative number of TLR2(+) granulocytes in "off-pump" patients at the finish of surgery and of TLR4(+) granulocytes on the first postoperative day.

CONCLUSIONS

We found characteristic patterns in the expression of TLR2 and TLR4 on monocytes and granulocytes in venous blood of patients undergoing cardiac surgery with or without CPB.

Effect of major abdominal surgery on endotoxin release and expression of Toll-like receptors 2/4

BACKGROUND

Surgery can cause endotoxemia, and endotoxin aggregates to Toll-like receptors and acts proinflammatory; repetitive endotoxin application can cause tolerance. The objective of the study is to characterize early inflammatory response and expression of TLR2/4 during major abdominal surgery.

MATERIALS AND METHODS

A prospective controlled study of 20 patients with elective major abdominal surgery was performed. Blood samples were collected before and at a defined time after surgery. Endotoxemia, capability of plasma to inactivate endotoxin, cytokine release of LPS-stimulated mononuclear cells, quantitative TLR mRNA expression, and plasma concentrations of TNFalpha, IL-6, C-reactive protein (CRP), alpha(1)-acid glycoprotein, transferrin, and albumin were measured.

RESULTS

Surgery caused endotoxemia (p = 0.053), and the capability of plasma to inactivate endotoxin was reduced (p = 0.0002). Two hours postoperatively, the plasma concentrations of TNFalpha and IL-6 peaked significantly, but the liberation capacity of mononuclear cells for cytokines (TNFalpha, IL-1beta, IL-6) was significantly reduced. The concentration of CRP and alpha(1)-acid glycoprotein peaked 48 h postoperatively, but those of transferrin and albumin were significantly decreased (p < 0.001, respectively). Median mRNA expression of TLR2 and TLR4 of mononuclear cells was not altered, and there was no obvious trend over time.

CONCLUSION

Major abdominal surgery is associated with endotoxemia, reduced capability of plasma to inactivate endotoxin, cytokine kinetics resembling those of healthy man after experimentally given LPS, and substantial acute-phase reaction. The cytokine liberation of mononuclear cells suggests a state of postoperative endotoxin tolerance. Despite these substantial changes, trends in TLR2/4 expression are not obvious.

Increased surface toll-like receptor 2 expression in superantigen shock

OBJECTIVE

Examination of the interaction between gram-positive bacterial superantigens and toll-like receptor 2 (TLR2) in health and critical illness.

DESIGN

Laboratory ex vivo model and prospective clinical, cohort study.

SETTING

Two research laboratories in university hospitals and two intensive care units.

SUBJECTS/PATIENTS

Laboratory study was performed in transfected HeLa cells and primary human monocytes from healthy volunteers. Clinical study used cells from 20 healthy controls and 45 critically ill patients with circulatory shock.

INTERVENTIONS

HeLa cells and purified monocytes were exposed to purified superantigens or isogenic bacterial supernatants and readout obtained by cytokine enzyme-linked immunosorbent assay, flow cytometry, and quantitative real-time polymerase chain reaction. Peripheral blood mononuclear cells from patients with circulatory shock were compared with controls using flow cytometry and measurement of cytokines after ligand exposure.

MEASUREMENTS AND MAIN RESULTS

Superantigens were unable to signal through ligation by TLR2. However, TLR2 was up-regulated on the surface of primary human monocytes, without detectable TLR2 messenger RNA neosynthesis, by a range of superantigens and superantigen-containing Streptococcus pyogenes supernatants, although not by isogenic superantigen-negative strains. Superantigen mutant constructs with disrupted major histocompatibility complex class II-binding sites did not support TLR2 up-regulation. TLR2 up-regulation was associated with an increase in the proinflammatory response to TLR2 ligands only at high ligand concentrations. TLR2 was up-regulated in a small subset of patients with severe S. pyogenes sepsis but not in patients with any other category of septic or circulatory shock; responses to TLR2 ligands were reduced in all categories of critically ill patient, however.

CONCLUSIONS

Superantigens up-regulate monocyte surface TLR2 expression through major histocompatibility complex class II signaling. Enhanced surface TLR2 expression may be a specific feature of patients with S. pyogenes-induced shock. Importantly, intensity of TLR2 signaling is not necessarily coupled to TLR2 expression when ligand concentrations are low or after onset of critical illness.

Toll-like receptor 2 and 4 expression after severe injury is not involved in the dysregulation of the innate immune system

BACKGROUND

Severe injury after trauma is associated with a diminished production of different proinflammatory cytokines after stimulation with bacterial cell wall components. The cellular mechanisms, leading to a decreased responsiveness especially of monocytes after multiple injuries have not yet been elucidated in detail. The expression of Toll-like receptors (TLR) on leukocytes is essential for recognition of bacterial components. We investigated the expression of TLR2 and 4 in correlation with gram-negative and gram-positive stimuli-dependent cytokine liberation after severe injury in comparison with that in healthy volunteers.

METHODS

In a prospective clinical experimental study, 12 trauma patients with an Injury Severity Score above 21 points and 14 healthy volunteers were analyzed. Heparinized whole blood samples of patients were collected within 48 hours after trauma and incubated in vitro with or without lipopolysaccharide (LPS) and peptidoglycan (PGN). TLR2 and TLR4 expression on monocytes was analyzed by flow cytometry. LPS- and PGN-induced tumor necrosis factor alpha (TNFalpha) and interleukin-8 production was measured by means of enzyme-linked immunosorbent assay.

RESULTS

Both LPS- and PGN-induced TNFalpha liberation were significantly reduced in severely injured patients. The surface expression of TLR2 was also significantly decreased on monocytes collected from trauma patients, whereas the expression of TLR4 remained unchanged. There was only a negative correlation between TLR2 expression and the liberation of TNFalpha after stimulation with LPS or PGN.

CONCLUSIONS

We conclude that diminished cytokine production after trauma cannot be explained simply by changes in TLR2 or TLR4 expression and that subsequent signaling cascades or additional receptors are involved in the blunted cytokine response after trauma.

Role of toll-like receptor 4 in the pathophysiology of severe acute pancreatitis in mice

PURPOSE

Multiple organ dysfunction and infection are major contributors to the high mortality associated with severe acute pancreatitis (SAP). Toll-like receptor 4 (TLR4) recognizes the lipopolysaccharide of gram-negative bacilli and is involved in inflammatory response and host defense. We examined the effects of TLR4-deficiency in SAP in mice.

METHODS

Closed duodenal loop-induced pancreatitis was induced in C3H/HeN (wild-type) and C3H/HeJ (TLR4-deficient) mice. We compared the severity of pancreatitis, liver and kidney dysfunction, and bacterial translocation to the pancreas between the two types of mice 12 h after the induction of SAP.

RESULTS

The severity of pancreatitis was similar in the two types of mice. The TLR4-deficient mice had significantly lower serum levels of aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine; significantly lower serum levels of interleukin-1 and tumor necrosis factor; reduced apoptosis of the liver and kidney; and a significantly higher rate of positive gram-negative bacterial cultures of the pancreas. TLR4 protein expression in the liver, kidney, and small intestine was increased 4 h after the induction of SAP, and decreased 12 h after the induction of SAP.

CONCLUSIONS

TLR4 is implicated in the mechanism of organ dysfunction and bacterial translocation in SAP, and TLR4 may trigger the inflammatory response and function defensively against infection.

Alterations of Toll-like receptor 4 expression on peripheral blood monocytes during the early stage of human acute pancreatitis

We sought to study Toll-like receptor 4 (TLR4) expression on peripheral blood mononuclear cells (PBMCs) during the early stage of human acute pancreatitis (AP). Thirty consecutive patients with acute pancreatitis admitted within 24 hr of onset of abdominal pain were enrolled prospectively in this study. Blood samples were taken by venipuncture at admission and on the third and seventh days after admission. PBMCs were isolated, and TLR4 and CD14 expression on PBMCs was detected by flow cytometer. Serum tumor necrosis factor (TNF)-alpha, interleukin, and lipase were detected simultaneously. Relations among these parameters were analysis. In mild AP, TLR4 expression increased on the first day of admission and then continued to decline for several days. On the seventh day, TLR4 expression was almost normal compared with that of the normal control. The alteration of serum TNF-alpha was coincidence with TLR4. We conclude that mononuclear-macrophages might be ignited through TLR4 (the gatekeeper of the innate immune system) and lead to production of TNF-alpha.

ALTERATIONS IN INFLAMMATORY CAPACITY AND TLR EXPRESSION ON MONOCYTES AND NEUTROPHILS AFTER CARDIOPULMONARY BYPASS

Cardiopulmonary bypass (CPB) is associated with immune paresis, which predisposes to the development of postoperative sepsis. The aims of this study were to characterize the ex vivo cytokine responses to bacterial cell wall components in whole blood from patients undergoing CPB and to determine whether altered leukocyte expression of Toll-like receptors (TLRs) is involved in immune paresis after CPB. We recruited 6 patients undergoing routine cardiac surgery with CPB. Preoperatively, at the end of CPB and 20 h later, blood was obtained, anticoagulated, and leukocyte surface expression of CD14, TLR2, and TLR4 was quantified by flow cytometry. In addition, blood was incubated at 37 degrees C in the presence of peptidoglycan (PepG) and/or lipopolysaccharide (LPS), and plasma cytokines were measured by enzyme immunoassay. At the end of CPB, ex vivo production of tumor necrosis factor alpha, interleukin (IL) 1beta, IL-8, and IL-10 in response to PepG or LPS was virtually abolished (P < 0.05). The following day, there was recovery of all cytokine responses to PepG. Tumor necrosis factor alpha and IL-1beta responses to LPS partially recovered, whereas IL-8 and IL-10 responses recovered. At the end of CPB, there was more than 50% reduction in neutrophil TLR2 and TLR4 expression (P < 0.05), with recovery to baseline the following day. There was a 29% reduction in monocyte TLR4 expression at the end of CPB (P < 0.05) and more than 120% increase in monocyte TLR2 and 4 expression the following day (P < 0.05). In conclusion, reduced ex vivo production of cytokines cannot be fully accounted for by downregulation of TLR expression, although receptor upregulation may contribute to the later recovery of responsiveness.

Clinical monitoring of innate cellular immunity of monocytes/macrophages by tumor necrosis factor alpha productivity in whole blood stimulated by lipopolysaccharide in patients with pancreatic cancer

OBJECTIVE

The aim of this study was to evaluate the tumor necrosis factor alpha (TNF-alpha) releasing capacity in whole blood stimulated by lipopolysaccharide (LPS) in patients with pancreatic cancer during the perioperative period, and before and after chemotherapy.

METHODS

The current study involved a total of 39 patients with pancreatic cancer (PC), who were further divided into a PC-Op group (n = 16, underwent pancreatectomy) and a PC-chemo group (n = 23, received chemotherapy). The control groups consisted of patients with hepatocellular carcinoma (n = 27, HCC group) and with benign diseases (n = 15, control group). Serial changes in TNF-alpha in whole blood stimulated by LPS were compared in various clinical settings.

RESULTS

Preoperative TNF-alpha levels in the PC-Op group were significantly lower than those in the HCC and control groups (P = 0.034). The TNF-alpha variable surgical index (s-index) was defined as the ratio of the preoperative TNF-alpha level to postoperative level in the PC-Op and HCC groups. Although the TNF-alpha s-index in the PC-Op group was significantly decreased on postoperative day 1 and recovered on postoperative day 3 (P < 0.002), there were no significant changes in the TNF-alpha s-index in the HCC group. The TNF-alpha variable chemotherapeutic index (c-index) was defined as the ratio of the TNF-alpha level before to that after chemotherapy in the PC-chemo group. The TNF-alpha c-index in all 7 patients was reduced to less than 0.3 until leukopenia appeared. Patients who had an increase in TNF-alpha production (TNF-alpha c-index >1.0) on day 3 or 7 after chemotherapy had significantly better cumulative survival than those with no increase (P < 0.033).

CONCLUSIONS

TNF-alpha production stimulated by LPS in the whole blood of patients with pancreatic cancer was low. Surgical stress and depressed immunocompetence might induce such profound decreases. A method of assessing the capability of leukocytes, particularly macrophages, to produce TNF-alpha could be useful for prognostis and for monitoring immunocompetence in patients with pancreatic cancer who have undergone chemotherapy.

Influence of major surgery on the mannan-binding lectin pathway of innate immunity

The mannan-binding lectin (MBL) pathway of complement activation is important in host defence against pathogens and possibly against cancer. We investigated the effect of major surgery on two central components of the MBL pathway; MBL and the MBL-associated serine protease MASP-2, and for comparison also measured the interleukin (IL)-6 and C-reactive protein (CRP) levels. Serial blood samples were obtained from patients belonging to two different cohorts. Cohort 1 comprised 60 patients undergoing open or laparoscopic colectomy for benign disease (n = 12) or colon cancer (n = 48). Cohort 2 comprised 27 patients undergoing elective, open surgery for colorectal cancer, and was included in order to cover blood sampling between days 2 and 6. As expected, the surgical stress induced a marked acute phase response, as evidenced by a large increase in IL-6 (18-fold) and CRP (13-fold) levels with maximum at 12 h and 2 days, respectively. However, in both cohorts the levels of MBL and MBL-associated serine protease 2 (MASP-2) were largely unaffected, except for a minor but significant increase around day 8 in cohort 1. The preoperative levels of IL-6 and CRP were correlated significantly in both cohorts (r = 0.71, P < 0.0001 and r = 0.65, P = 0.005, respectively). Preoperative MASP-2 correlated with preoperative CRP (r = 0.59, P = 0.001) and IL-6 (r = 0.55, P = 0.02) in cohort 2 only. In contrast to the marked effects on the levels of IL-6 and CRP, the surgery influenced only marginally the two proteins of the MBL pathway.

Intestinal anastomosis surgery with no septic shock primes for a dysregulatory response to a second stimulus

BACKGROUND

Major surgery is believed to contribute to immune dysregulation and high susceptibility to microbes. Recently, the inflammatory "two-hit" model has been accepted to elucidate development of multiple organ failure in surgical patients. Our purpose was to examine whether intestinal surgery, which causes a minor insult with no septic shock, may modify the immune response to exogenous LPS as a second stimulus.

MATERIALS AND METHODS

Using a rat intestinal transection and anastomosis surgery model, we sequentially examined blood cell counts, body temperatures, and plasma cytokines. Rats were administered with LPS intravenously or intratracheally various days after surgery. Phagocytic activity and TNFalpha production in bronchoalveolar lavage (BAL) cells, plasma cytokines, and survival rates were evaluated.

RESULTS

The surgery itself caused no severe shock or circulating cytokine elevation, whereas the number of granulocytes in the blood was significantly elevated after surgery. LPS-induced elevation of circulating IFNgamma attenuated 3 days after surgery. In contrast, IL-10 was enhanced 3-10 days after surgery. Hyporesponsiveness of BAL cells to LPS was observed 3 days after surgery but not the next day after surgery. However, rats intratracheally exposed to LPS 10-13 days after surgery exhibited higher mortality.

CONCLUSIONS

Although our surgical procedure was not supposed to be a severe insult, it sufficiently primed rats for an altered response to a second stimulus (endotoxin), which included enhanced mortality. This study provided an improved understanding of pathophysiological changes following surgery and described a useful model for developing preventive and therapeutic strategies for complications after surgery.