Chemokine regulation of neutrophil function in surgical inflammation

Messenger RNA Expression of Selected Factors at Different Sites of the Bovine Endometrium Associated With Uterine Health

Recent studies have elucidated the role of several pro-inflammatory factors as mediators of inflammatory processes in the bovine endometrium. Only few studies, however, have analyzed samples collected from different regions of the uterus of the same animal. In this study, we tested the hypothesis that on a molecular level, clinical endometritis is characterized by inflammatory responses spread over the entire endometrium. Furthermore, we assume that subclinical endometritis is described by an inflammation of local regions of the uterus. Therefore, the objective of this study was to assess the mRNA expression of uterus-associated pro-inflammatory factors at five pre-defined endometrial sites, i.e., corpus uteri, left horn base, left horn tip, right horn base, and right horn tip, in cows with clinical and subclinical endometritis and in healthy controls. We analyzed the mRNA expression of interleukin 1 alpha, interleukin 1 beta, C-X-C motif chemokine ligand 8, prostaglandin-endoperoxide synthase 2, protein tyrosine phosphatase receptor type C, carcinoembryonic antigen related cell adhesion molecule 1, and mucin 4 and 16. Based on vaginoscopy and endometrial cytology (≥ 5% polymorphonuclear neutrophils) between 28 to 34 days in milk, 18 Simmental cows were categorized in clinical endometritis group (n = 7), subclinical endometritis group (n = 4), and healthy group (n = 7). In general, the analyses revealed a great variation of mRNA expression between sites and animals. Differences were found between different uterine health statuses, but the variation between the sampling sites within the groups was not significant (P > 0.05). This indicates that inflammatory processes at the end of the postpartum period can be regarded as multi-focal or spread throughout the uterus independent from the uterine health status.

Evaluation of bone healing following Er:YAG laser ablation in rat calvaria compared with bur drilling

The Er:YAG laser is currently used for bone ablation. However, the effect of Er:YAG laser irradiation on bone healing remains unclear. The aim of this study was to investigate bone healing following ablation by laser irradiation as compared with bur drilling. Rat calvarial bone was ablated using Er:YAG laser or bur with water coolant. Er:YAG laser effectively ablated bone without major thermal changes. In vivo micro-computed tomography analysis revealed that laser irradiation showed significantly higher bone repair ratios than bur drilling. Scanning electron microscope analysis showed more fibrin deposition on laser-ablated bone surfaces. Microarray analysis followed by gene set enrichment analysis revealed that IL6/JAK/STAT3 signaling and inflammatory response gene sets were enriched in bur-drilled bone at 6 hours, whereas the E2F targets gene set was enriched in laser-irradiated bone. Additionally, Hspa1a and Dmp1 expressions were increased and Sost expression was decreased in laser-irradiated bone compared with bur-drilled bone. In granulation tissue formed after laser ablation, Alpl and Gblap expressions increased compared to bur-drilled site. Immunohistochemistry showed that osteocalcin-positive area was increased in the laser-ablated site. These results suggest that Er:YAG laser might accelerate early new bone formation with advantageous surface changes and cellular responses for wound healing, compared with bur-drilling.

Ultrasonic incisions produce less inflammatory mediator response during early healing than electrosurgical incisions

As the use of laparoscopic surgery has become more widespread in recent years, the need has increased for minimally-invasive surgical devices that effectively cut and coagulate tissue with reduced tissue trauma. Although electrosurgery (ES) has been used for many generations, newly-developed ultrasonic devices (HARMONIC® Blade, HB) have been shown at a macroscopic level to offer better coagulation with less thermally-induced tissue damage. We sought to understand the differences between ES and HB at a microscopic level by comparing mRNA transcript and protein responses at the 3-day timepoint to incisions made by the devices in subcutaneous fat tissue in a porcine model. Samples were also assessed via histological examination. ES-incised tissue had more than twice as many differentially-expressed genes as HB (2,548 vs 1,264 respectively), and more differentially-expressed proteins (508 vs 432) compared to control (untreated) tissue. Evaluation of molecular functions using Gene Ontology showed that gene expression changes for the energized devices reflected the start of wound healing, including immune response and inflammation, while protein expression showed a slightly earlier stage, with some remnants of hemostasis. For both transcripts and proteins, ES exhibited a greater response than HB, especially in inflammatory mediators. These findings were in qualitative agreement with histological results. This study has shown that transcriptomics and proteomics can monitor the wound healing response following surgery and can differentiate between surgical devices. In agreement with clinical observations, electrosurgery was shown to incur a greater inflammatory immune response than an ultrasonic device during initial iatrogenic wound healing.

Lymphatic pump manipulation mobilizes inflammatory mediators into lymphatic circulation

Lymph stasis can result in edema and the accumulation of particulate matter, exudates, toxins and bacteria in tissue interstitial fluid, leading to inflammation, impaired immune cell trafficking, tissue hypoxia, tissue fibrosis and a variety of diseases. Previously, we demonstrated that osteopathic lymphatic pump techniques (LPTs) significantly increased thoracic and intestinal duct lymph flow. The purpose of this study was to determine if LPT would mobilize inflammatory mediators into the lymphatic circulation. Under anesthesia, thoracic or intestinal lymph of dogs was collected at resting (pre-LPT), during four minutes of LPT, and for 10 min following LPT (post-LPT), and the lymphatic concentrations of interleukin-2 (IL-2), IL-4, IL-6, IL-10, interferon- γ, tissue necrosis factor α,  monocyte chemotactic protein-1 (MCP-1), keratinocyte chemoattractant, superoxide dismutase (SOD) and nitrotyrosine (NT) were measured. LPT significantly increased MCP-1 concentrations in thoracic duct lymph. Further, LPT increased both thoracic and intestinal duct lymph flux of cytokines and chemokines as compared with their respective pre-LPT flux. In addition, LPT increased lymphatic flux of SOD and NT. Ten minutes following cessation of LPT, thoracic and intestinal lymph flux of cytokines, chemokines, NT and SOD were similar to pre-LPT, demonstrating that their flux was transient and a response to LPT. This re-distribution of inflammatory mediators during LPT may provide scientific rationale for the clinical use of LPT to enhance immunity and treat infection.

Assessment of chemokine profiles in human skin biopsies by an immunoaffinity capillary electrophoresis chip

Atopic dermatitis is a skin condition resulting in a skin rash from exposure to environmental factors. Skin biopsies taken from patients suffering from atopic dermatitis were micro-dissected and analyzed using a microchip-based immunoaffinity CE system for the presence of CXCL1, CXCL5 and CXCL8 and CCL1, CCL3 and CCL5 chemokines. Disposable immunoaffinity disks with immobilized antibodies were used to capture the CXC and CC chemokines from the homogenized skin samples. The captured analytes were then labeled with AlexaFluor 633, eluted from the disk and separated by CE. The labeled chemokines were identified and quantified by laser induced fluorescence. The total analysis time was less than 40min, including the biopsy microdissection, pre-analysis preparation of the sample and the ICE-CHIP analysis, which took less than 10min with inter- and intra-assay CV's below 6.4%. Microchip-based immunoaffinity CE could distinguish between normal skin biopsies and those with inflammation. Patients with neutrophil cellular infiltrates by histopathology showed increased concentrations of CXCL1, CXCL5 and CXCL8 while increases of CCL1, CCL3 and CCL5 corresponded to the patient group demonstrating monocytic and T-lymphocyte infiltration by histopathology. This system demonstrates the ability to identify and quantify immunochemical analytes in frozen sections taken from clinical histopathology samples.

Time-dependent mRNA expression of selected pro-inflammatory factors in the endometrium of primiparous cows postpartum

BACKGROUND

Inflammatory processes and infections of the uterine wall must be accepted as a physiological event in dairy cows after calving. This might result in clinical or subclinical endometritis which is assumed to impair reproductive performance in the current lactation. Several cytokines and acute phase proteins have been discussed as local and systemic mediators of these inflammatory processes. The aim of the present study was to investigate the endometrial mRNA expression of the chemokine CXC ligand 5 (CXCL5), interleukin 1β (IL1B), IL6, IL8, tumour necrosis factor alpha (TNF), prostaglandin-endoperoxide synthase 2 (PTGS2) and haptoglobin (HP) in the postpartum period.

METHODS

Endometrial samples were obtained from primiparous cows (n = 5) on days 10, 17, 24, 31, 38 and 45 postpartum (pp) using the cytobrush technique. Cytological smears were prepared from cytobrush samples to determine the proportion of polymorphonuclear neutrophils (PMN). Total RNA was extracted from endometrial samples, and real-time RT-PCR was performed.

RESULTS

A time-dependent mRNA expression of the investigated factors was found for the course of the postpartum period. In detail, a significantly higher expression of these factors was observed on day 17 pp compared to day 31 pp. Furthermore, the proportion of PMN peaked between days 10-24 pp and decreased thereafter to low percentages (< 5%) on day 31 pp and thereafter. In addition, CXCL5, IL1B, IL8 and HP mRNA expression correlated significantly with the proportion of PMN (P < 0.05). A significantly higher CXCL5, IL1B, IL6, IL8, PTGS2 and TNF mRNA content was observed in samples from cows with an inflamed endometrium compared with samples from cows with a healthy endometrium (P < 0.05).

CONCLUSIONS

These results show that inflammatory cytokines and acute phase proteins are expressed in the bovine endometrium in a time-related manner during the postpartum period, with a significant expression peak on day 17 pp as a possible mucosal immune response in the uterus. The evaluation of the expression patterns of such candidate genes may reveal more information than only determining the percentage of PMN to judge the severity of an inflammation.

Selected pro-inflammatory factor transcripts in bovine endometrial epithelial cells are regulated during the oestrous cycle and elevated in case of subclinical or clinical endometritis

Endometrial cells take part in embryo-maternal communication, as well as supporting the immune system in defending against invading pathogens. The aim of the present study was to examine the mRNA expression of factors that have been suggested to be involved in both events in the bovine endometrial epithelium, namely bovine granulocyte chemotactic protein 2 (CXCL5), interleukin-1 beta (IL1B), IL6, IL8, tumour necrosis factor (TNF), cyclooxygenase 2 (PTGS2) and haptoglobin (HP). Samples were collected in vivo from cows on Days 21-27 postpartum by the cytobrush method to evaluate the correlation between inflammatory factors and uterine health (cows with signs of clinical or subclinical endometritis and healthy cows). Bovine uteri were collected at the abattoir to investigate oestrous cycle-dependent mRNA expression patterns. Real-time reverse transcription-polymerase chain reaction revealed that the expression of CXCL5, IL1B, IL8 and TNF mRNA was significantly higher in cows with subclinical or clinical endometritis compared with healthy cows. The expression of CXCL5, IL1B and IL8 mRNA was increased around ovulation compared with the luteal phase. There was no indication of either oestrous cycle-dependent expression or a correlation with uterine health for IL6, PTGS2 and HP transcripts. These results suggest that CXCL5, IL1B, IL8 and TNF may represent potential marker genes for the detection of cows with subclinical endometritis and for monitoring new therapeutic approaches.

Dietary restriction modifies certain aspects of the postoperative acute phase response

BACKGROUND

Lifespan extension is achieved through long-term application of dietary restriction (DR), and benefits of short-term dietary restriction on acute stress and inflammation have been observed. So far, the effects of short-term DR in humans are relatively unknown. We hypothesized that short-term DR in humans reduces the acute phase response following a well defined surgical trauma.

METHODS

Thirty live kidney donors were randomized between 30% preoperative dietary restriction followed by 1 d of fasting (n=17) or a 4 d ad libitum regimen (n=13) prior to surgery. Leukocyte subsets and numbers and serum cytokine levels were determined. Whole blood was stimulated with lipopolysaccharide (LPS) and cytokine production was determined.

RESULTS

A clear trend towards lower numbers of postoperative circulating leukocytes was observed in the DR group. IL-8 serum levels were significantly higher in the DR group over the first 6 postoperative d (P=0.018). After LPS stimulation, significantly less TNF-α (P=0.001) was produced by blood obtained postoperatively compared with preoperative blood from the DR group. This was not observed in the control group.

CONCLUSIONS

A relatively short preoperative dietary restriction regimen was able to modify certain aspects of the postoperative acute phase response. These data warrant further studies into the dietary conditions that improve stress resistance in humans. (Dutch Trial Registry number: NTR1875).

CXCL6 (granulocyte chemotactic protein-2): a novel chemokine involved in the innate immune response of the amniotic cavity

PROBLEM

CXCL6 is a potent pro-inflammatory neutrophil chemoattractant and activator whose activity during pregnancy is not well-established. The purpose of this study was to determine if CXCL6 is present in amniotic fluid (AF) and if CXCL6 concentrations in AF change with labor (pre-term and term) or intra-amniotic infection/inflammation (IAI).

METHOD OF STUDY

A cross-sectional study was designed including the following groups: (1) mid-trimester (n = 65); (2) term no labor (n = 20); (3) term labor (n = 44); (4) patients with pre-term labor (PTL) with subsequent term delivery (n = 57); (5) PTL without IAI who delivered pre-term (n = 47); and (6) PTL with IAI (n = 62). AF CXCL6 concentrations were determined by ELISA.

RESULTS

CXCL6 was present in all term samples, but undetectable in 64/65 mid-trimester specimens. Patients with PTL and IAI had a significantly higher median AF CXCL6 concentration than those with PTL without IAI [228.9 pg/mL (0.0-8344.8) versus 55.7 pg/mL (0-454.4); P < 0.05] and those with PTL and term delivery [41.5 pg/mL (0-279.0); P < 0.05]. The median AF CXCL6 concentration did not change with spontaneous term labor [term no labor: 81.1 pg/mL (8.5-201.7) versus term labor: 75.2 pg/mL (6.7-378.7): P = 0.7].

CONCLUSION

(1) CXCL6 is detectable in AF and its concentration increases with gestational age; (2) IAI results in increased AF CXCL6 concentrations, suggesting that CXCL6 plays a role in the deployment of an inflammatory response; (3) In contrast to related chemokines, specifically IL-8, AF CXCL6 does not appear to be involved in spontaneous term parturition. These observations are novel, and suggest a role for CXCL6 in the innate immune response to microbial invasion of the amniotic cavity.

Surgery-Derived Reactive Oxygen Species Produced by Polymorphonuclear Leukocytes Promote Tumor Recurrence: Studies in an In Vitro Model

Tissue injury induces the acute phase response, aimed at minimizing damage and starting the healing process. Polymorphonuclear leukocytes (PMNs) respond to the presence of specific chemoattractants and begin to appear in large numbers. The aim of this study was to investigate the influence of reactive oxygen species (ROS) produced by PMNs on the interaction between colon carcinoma cells and mesothelial cells. An experimental human in vitro model was designed using Caco-2 colon carcinoma cells and primary cultures of mesothelial cells. Tumor cell adhesion to a mesothelial monolayer was assessed after preincubation of the mesothelium with stimulated PMNs and unstimulated PMNs. Mesothelial cells were also incubated with xanthine/xanthine oxidase (X/XO) complex producing ROS after which adhesion of Caco-2 cells was investigated and the expression of adhesion molecules (ICAM-1, VCAM-1, and CD44) by means of enzyme immunoassay. In the control situation the average adhesion of Caco-2 cells to the mesothelial monolayers was 23%. Mesothelial monolayers incubated with unstimulated PMNs showed a 25% increase of tumor cell adhesion (P < 0.05). The adhesion of tumor to the monolayers incubated with the N-formyl-methionyl-leucyl-phenylalanine-stimulated PMNs increased with 40% (P < 0.01). Incubation of the mesothelium with X/XO resulted in an enhancement of adhesion of Caco-2 cells of 70% and an up-regulation of expression of ICAM-1, VCAM-1, and CD44. This study reveals an increase of tumor cell adhesion to the mesothelium induced by incubating the mesothelial monolayers with PMNs. PMNs are producing a number of products, like proteolytic enzymes, cytokines, and ROS. These factors up-regulate the expression of adhesion molecules and in that way stimulate the adhesion of tumor to the mesothelium.

The Release of Systemic Inflammatory Mediators Is Independent of Cardiopulmonary Bypass Temperature

OBJECTIVE

The aim of this study was to investigate the effect of systemic CPB temperature on the production of the key mediators of the systemic inflammatory response to coronary artery bypass graft (CABG) surgery.

DESIGN

Randomized clinical study.

SETTING

University hospital.

PARTICIPANTS

Thirty patients undergoing first-time CABG surgery.

INTERVENTIONS

The patients were randomized to hypothermic (32 degrees C, n = 15) or normothermic (36 degrees C, n = 15) CPB.

MEASUREMENTS AND MAIN RESULTS

Plasma interleukin (IL)-6, IL-8, IL-10, C-reactive protein (CRP), cortisol, and neutrophils were measured the day before operation, at closure of the sternum, and 4, 16, and 44 hours later. The cytokine, CRP, cortisol, and neutrophil responses were independent of temperature during CPB with peak concentrations of IL-10 at closure of the sternum followed by IL-6, IL-8, cortisol, neutrophils, and finally CRP. A correlation between maximal plasma concentrations of IL-10 and cortisol was seen in both groups after surgery (p = 0.02). Drainage after surgery was lower after normothermic CPB (p=0.02), with no difference in the requirement for blood transfusion. All patients were discharged from the intensive care unit within 24 hours after surgery.

CONCLUSIONS

The release of systemic inflammatory mediators after cardiac surgery was independent of mild hypothermia (32 degrees C) versus normothermia (36 degrees C) during CPB.

Differential production of cytokines following colorectal surgery

BACKGROUND

Colorectal surgery is associated with a number of postoperative complications, including anastomotic leak and local recurrence. These complications are more common after rectal surgery than after colon surgery. Cytokines are secreted into the peritoneal cavity after colorectal surgery and have a number of metabolic and immunological effects. Hence we suggested that differential secretion of these may contribute to the differences in complications between colon and rectal surgeries.

METHODS

Patients undergoing either elective rectal excision or colectomy for benign or malignant disease were recruited into the study. The region in relation to the anastomosis was drained with a silastic drain for 12-18 h. Drain fluid was collected on the morning following surgery. The drain fluid was assayed for interleukin (IL)-1beta, tumour necrosis factor-alpha, IL-6, IL-8, IL-10 and IL-13 using multiplexed biomarker immunoassays.

RESULTS

Interleukin-8 concentrations were significantly higher in the region of the anastomosis after rectal excision compared with colectomy. Also, IL-6 levels were very high in both groups, but there was no significant difference between the groups. Although the concentrations of IL-10 were higher in the rectal group relative to the colectomy group, only low levels of this cytokine were present in the drain fluids. No other cytokines were consistently detected in significant concentrations.

CONCLUSION

This study has shown that the concentration of IL-8 in the region of the anastomosis of patients who have undergone rectal surgery is much higher than those who have undergone colonic surgery. The increased level of IL-8 may provide a milieu conducive to local recurrence and anastomotic leak.

Impaired neutrophil chemotaxis in sepsis associates with GRK expression and inhibition of actin assembly and tyrosine phosphorylation

The deregulation of inflammatory response during sepsis seems to reflect the overproduction of mediators, which suppress leukocyte functions. We investigated the intracellular mechanisms underlying the inability of neutrophils from severe septic patients to migrate toward chemoattractants. Patients with sepsis (52) and 15 volunteers were prospectively enrolled. Patients presented increased circulating levels of tumor necrosis factor-alpha, interferon-gamma, interleukin (IL)-8, and IL-10. Patients showed reduced neutrophil chemotaxis to formyl-methionyl-leucyl-phenylalanine (FMLP), leukotriene B4 (LTB4) or IL-8. No difference in the transcription or expression of the IL-8 receptor, CXCR1, was detected in neutrophils from controls and patients. However, septic neutrophils failed to increase tyrosine phosphorylation and actin polymerization in response to IL-8 or LTB4. In contrast, septic neutrophils, similar to controls, showed phagocytic activity that induced actin polymerization and augmented phosphotyrosine content. Treatment of control neutrophils with cytokines and lipopolysaccharide (LPS) to mimic endogenous septic environment inhibited actin polymerization and tyrosine phosphorylation in response to IL-8 or LTB4. High expression of G protein-coupled receptor kinase 2 (GRK2) and GRK5 was detected in septic neutrophils and control cells treated with cytokines plus LPS. Data suggest that endogenous mediators produced during sepsis might continually activate circulating neutrophils, leading to GRK activation, which may induce neutrophil desensitization to chemoattractants.

Modulation of neutrophil apoptosis in plasma of patients after orthognathic surgery

BACKGROUND

Human neutrophils undergo rapid apoptosis during in vitro culture. The aim of this study was to investigate the role of interleukin-8 (IL-8) on neutrophil apoptosis in surgery-induced inflammation.

MATERIALS AND METHODS

Blood samples were drawn from 21 patients with mandibular prognathism 2 days before, and 1 and 5 days after orthognathic surgery. The IL-8 levels in the separated plasma were measured using an ELISA kit. The expression of two receptors for IL-8, CXCR1, and CXCR2, and their role in neutrophil apoptosis was evaluated using a flow cytometer.

RESULTS

The IL-8 levels in the plasma were correlated with acute inflammatory markers, such as peripheral blood neutrophil counts and C-reactive protein levels. Both IL-8 receptors were markedly raised in patient-derived neutrophils 1 day post-operatively. Recombinant IL-8 (0-100 ng/ml) suppressed apoptosis in fresh-isolated neutrophils from healthy donors dose-dependently. Neutrophil apoptosis 1 day post-operatively was slightly accelerated in the presence of fetal bovine serum compared to the value 2 days pre-operatively and 5 days post-operatively. In contrast, in the presence of autogenous plasma, neutrophil apoptosis was significantly suppressed 1 day post-operatively compared to the value 2 days pre-operatively and 5 days post-operatively. Moreover, the anti-apoptotic effect of plasma on neutrophil apoptosis was partially decreased by the addition of anti-IL-8 neutralizing antibody.

CONCLUSIONS

These results suggest that circulating neutrophils are susceptible to augmentation by IL-8 through the reinforcement of IL-8 receptors in acute inflammatory conditions. Furthermore, IL-8 may, in part, contribute to the regulation of neutrophil survival during the inflammatory response.

Alpha-chemokine receptor blockade reduces high mobility group box 1 protein-induced lung inflammation and injury and improves survival in sepsis

High mobility group box 1 (HMGB1) protein, a late mediator of lethality in sepsis, can induce acute inflammatory lung injury. Here, we identify the critical role of alpha-chemokine receptors in the HMGB1-induced inflammatory injury and show that alpha-chemokine receptor inhibition increases survival in sepsis, in a clinically relevant time frame. Intratracheal instillation of recombinant HMGB1 induces a neutrophilic leukocytosis, preceded by alveolar accumulation of the alpha-chemokine macrophage inflammatory protein-2 and accompanied by injury and increased inflammatory potential within the air spaces. To investigate the role of alpha-chemokine receptors in the injury, we instilled recombinant HMGB1 (0.5 microg) directly into the lungs and administered a subcutaneous alpha-chemokine receptor inhibitor, Antileukinate (200 microg). alpha-Chemokine receptor blockade reduced HMGB1-induced inflammatory injury (neutrophils: 2.9 +/- 3.2 vs. 8.1 +/- 2.4 x 10(4) cells; total protein: 120 +/- 48 vs. 311 +/- 129 microg/ml; reactive nitrogen species: 2.3 +/- 0.3 vs. 3.5 +/- 1.3 microM; and macrophage migration inhibitory factor: 6.4 +/- 4.2 vs. 37.4 +/- 15.9 ng/ml) within the bronchoalveolar lavage fluid, indicating that HMGB1-induced inflammation and injury are alpha-chemokine mediated. Because HMGB1 can mediate late septic lethality, we administered Antileukinate to septic mice and observed increased survival (from 58% in controls to 89%) even when the inhibitor treatment was initiated 24 h after the induction of sepsis. These data demonstrate that alpha-chemokine receptor inhibition can reduce HMGB1-induced lung injury and lethality in established sepsis and may provide a novel treatment in this devastating disease.

Candida albicans and Streptococcus salivarius modulate IL-6, IL-8, and TNF-alpha expression and secretion by engineered human oral mucosa cells

We investigated the involvement of oral epithelial cells via two cytokines (IL-6 and TNF-alpha) and one chemokine (IL-8) in local defences against live yeast (Candida albicans) and bacteria (Streptococcus salivarius) using an engineered human oral mucosa model. We report that the yeast changed from the blastospore to the hyphal form and induced significant tissue disorganization at later contact periods (24 and 48 h) compared to the bacteria. However, this effect did not reduce the viability or total number of epithelial cells. Gene activation analyses revealed that IL-6, IL-8 and TNF-alpha mRNA levels rose in tissues in contact with live C. albicans or S. salivarius. Gene activation was followed by an upregulation of protein secretion. IL-6 levels were higher after contact with C. albicans than with S. salivarius. IL-8 levels after contact with S. salivarius were higher than with C. albicans. Our study suggests that S. salivarius is more efficient at inducing proinflammatory mediator release than C. albicans. These results provide additional evidence for the contribution of oral epithelial cells to the inflammatory response against fungi and bacteria.

Polymorphonuclear neutrophils in posttraumatic osteomyelitis: cells recovered from the inflamed site lack chemotactic activity but generate superoxides

The pathogenesis of posttraumatic osteomyelitis, one of the major complications after orthopedic surgery, is not yet understood. Formation of bacterial biofilms on the implant is presumed, conferring resistance to antibiotic therapy and probably also to the host defense mechanisms. In that context, the polymorphonuclear neutrophils (PMN) having infiltrated the infected site were recovered and characterized phenotypically and functionally. Loss of CD62L and upregulation of CD14 were seen, as was expression of CD83. Expression of the latter is dependent on de novo protein synthesis and thus is indicative of an extended life span and a transdifferentiation of the PMN at the infected site. The infiltrated PMN had lost their chemotactic activity, whereas the capacity to produce superoxides was preserved and in some patients even enhanced. In vitro experiments done in parallel showed that long-term culture with interferon-gamma resulted in similar alterations of PMN: loss of chemotactic activity, whereas other functions of PMN, such generation of superoxides and phagocytosis of opsonized bacteria, were preserved or even enhanced. The loss of the migratory capacity of PMN having already emigrated from the blood vessel to the infected site is not expected to affect the host defense negatively. Assuming, however, that bacteria are organized as a biofilm and that infiltration into this biofilm is required for phagocytosis of the bacteria, our data could to some extent explain why despite being activated, the PMN are not able to control the infection. By releasing their cytotoxic, proteolytic, and collagenolytic potential, PMN might instead contribute to tissue destruction and eventually to osteolysis.

Short-term exposure to urban dust alters the mediator release of human nasal mucosa

LEARNING OBJECTIVES

Identify any changes in cytokine (mediator) concentrations in nasal secretions after healthy individuals were experimentally exposed to urban dust. Recall what connection there was, if any, between post-exposure cytokine levels in nasal secretions on the one hand, and, on the other, counts of inflammatory cells and nasal symptoms. Report the investigators' conclusions as to whether exposure to urban dust is a cause of persistent inflammation and chronic airway disease.

ABSTRACT

Thirty healthy volunteers were nasally exposed to control air and urban dust (SRM 1649a) in concentrations of 150 and 500 microg/m3 for 3 hours. Thirty minutes, 8 hours, and 24 hours after exposure, nasal cytologies were obtained, and nasal secretion levels of interleukin (IL)-1beta, IL-6, IL-8, tumor necrosis factor-alpha, epithelial neutrophil activating protein-78, monocyte chemoattractant protein-1, and substance P were determined. Twenty-four hours after exposure to 500 microg/m3, nasal secretion levels of IL-1beta increased 72.3% (0-150.2%, P=0.002), levels of IL-6 increased 42.2% (-28-161.9%,P=0.01), and levels of IL-8 increased 19.7% (-20.3-60.5%, P=0.03; median and 95% confidence interval). These cytokines correlated closely with nasal inflammatory cell counts. No exposure-related changes of tumor necrosis factor-alpha, monocyte chemoattractant protein-1, epithelial neutrophil activating protein-78, and substance P levels were observed. These results provide experimental support for recent epidemiological observations that short-term increase of outdoor particulate matter concentration increases the frequency of upper respiratory diseases.

Cytokines in patients with polytrauma

Patients with multiple injuries have alterations in hemodynamic, metabolic, and immune responses that largely are orchestrated by endogenous mediators referred to as cytokines. At the molecular level cytokines act as architects constructing a blueprint which ultimately will become the clinical "Big Picture"; however, the exact role and extent each cytokine has is still in question. In addition, the surface of research opportunities has nearly been scratched regarding the best way to control or manipulate the cytokine response in efforts to improve care for the trauma patient. Systemically organisms respond to injury regardless of the cause (hemorrhage, ischemia, reperfusion, fracture, and tissue damage) by attempting to restore homeostasis, which involves a coordination of the immune, cardiovascular, endocrine, and nervous systems. This systemic response can result in severe immunologic compromise that threatens the survival of patients with trauma. It seems that it is this balance or imbalance of cytokines, along with other associative factors, that controls the eventual clinical pathway a patient will take. Blood mediator concentrations often parallel the inflammatory process, and high levels of cytokines can be followed by severe organ dysfunction. Certain cytokine levels, such as the interleukins, can be used in predictive ways to correlate organ failure in multiply injured patients. Although much more research must be done, there is great promise in the study of cytokines through basic science research and clinical trials.

Posttraumatic inflammation is a complex response based on the pathological expression of the nervous, immune, and endocrine functional systems

The successive phases that make up both the local and systemic posttraumatic acute inflammatory response could represent the expression of three concatenated pathological or "primitive" functional systems with trophic properties: the nervous, immune, and endocrine ones. The nervous functional system would play an important role in the phenomenon of ischemia-reperfusion, which would be represented by nutrition by diffusion that is either anaerobic (ischemia) or with defective use of oxygen (reperfusion) and, thus, with a limited energy requirement. The immune functional system would be represented by the infiltration of the tissues by inflammatory cells and bacteria, which would become mediators in providing nutrition to the injured tissues. Although the use of oxygen would still be defective, hypermetabolism and fever would occur. In these inflammatory response phases, the lymphatic is the most important circulation. The endocrine functional system would be the most specialized and would have high energy requirements because it would be represented by the blood capillary-mediated nutrition. Highly specialized epithelial cells would already possess a perfected oxidative metabolism. The successive expression of these three functional systems during embryonic development and also during the evolutionary development of our species could explain why the inflammatory response is a ubiquitous mechanism that is common to multiple diseases, because it is an integrator of the ontogeny and phylogeny.

Inflammatory chemoreceptor cross-talk suppresses leukotriene B4 receptor 1-mediated neutrophil calcium mobilization and chemotaxis after trauma

G protein-coupled chemoattractants recruit neutrophils (PMN) to sites of injury and infection. The leukotrienes (LT) and CXC chemokines (CXC) and their receptors (BLT1/BLT2 and CXCR1/CXCR2) are all known to play roles in these responses. Each system has been studied separately in vitro, but in vivo they act concurrently, and the clinical interactions between the two systems are unstudied. We prospectively studied calcium mobilization and chemotactic responses to LTB(4) in PMN from major trauma patients. The responses of the high affinity BLT1 receptor were suppressed at the 3-day postinjury time point, but recovered by 1 wk. Trauma patients had transient elevations of plasma LT and CXC levels. Functional deficits identical with those in trauma PMN were reproduced in vitro by exposing healthy PMN to CXCs at the elevated plasma concentrations found. Functional responses to LTB(4) were suppressed by cross-talk with CXC and BLT2 receptors that desensitize BLT1. Since the suppression of intracellular calcium mobilization was prominent, we also studied the role of suppressed cell calcium mobilization in the defective chemotactic responses to LTB(4). We noted that PMN chemotaxis to LTB(4) showed far more dependence on store-operated calcium entry than on the release of cellular calcium stores, and that store-operated calcium responses to BLT1 activation were markedly inhibited during the same time period as was chemotaxis. The intermittent release of inflammatory mediators after injury can blunt PMN responses to LTs by suppressing BLT1 as well as downstream calcium entry. Diminished LT receptor activity due to cross-talk with CXC receptors can inhibit PMN recruitment to infective sites. This may predispose injured patients to septic complications.

Protection of innate immunity by C5aR antagonist in septic mice

Innate immune functions are known to be compromised during sepsis, often with lethal consequences. There is also evidence in rats that sepsis is associated with excessive complement activation and generation of the potent anaphylatoxin C5a. In the presence of a cyclic peptide antagonist (C5aRa) to the C5a receptor (C5aR), the binding of murine 125I-C5a to murine neutrophils was reduced, the in vitro chemotactic responses of mouse neutrophils to mouse C5a were markedly diminished, the acquired defect in hydrogen peroxide (H2O2) production of C5a-exposed neutrophils was reversed, and the lung permeability index (extravascular leakage of albumin) in mice after intrapulmonary deposition of IgG immune complexes was markedly diminished. Mice that developed sepsis after cecal ligation/puncture (CLP) and were treated with C5aRa had greatly improved survival rates. These data suggest that C5aRa interferes with neutrophil responses to C5a, preventing C5a-induced compromise of innate immunity during sepsis, with greatly improved survival rates after CLP.

Expression of chemokine receptors CXCR1 and CXCR2 during cardiopulmonary bypass

OBJECTIVE

This study investigated the effects of cardiopulmonary bypass on neutrophil expression of chemokine receptors, CXCR1 and CXCR2, and the beta2 integrin CD11b.

METHODS

Ten patients undergoing coronary artery grafting with cardiopulmonary bypass were studied. Blood samples were collected preoperatively, before bypass, at termination of bypass, and 12 to 18 hours postoperatively. In vitro studies were performed on control subjects to determine changes in the surface expression of CXCR1, CXCR2, and CD11b on stimulation with interleukin 8. Receptor expression was measured by flow cytometry. Plasma levels of interleukin 8 from the patients were determined by enzyme-linked immunoassay.

RESULTS

After bypass, CXCR2 expression fell by 66% (P <.0001) and remained low postoperatively (P <.0001). CXCR1 expression persisted at preoperative levels. CD11b expression increased significantly after bypass (P <.0001), returning to prebypass levels postoperatively. In vitro studies showed a dose-related fall of both CXCR1 (P <.0001) and CXCR2 expression (P <.0001) and a significant rise in CD11b expression (P <.0001). Plasma interleukin 8 increased significantly after bypass (P <.0001), remaining elevated 12 to 18 hours postoperatively (P =.02). Correlations between interleukin 8 levels and CXCR2 expression (P <.0001) and CD11b expression (P <.03) were demonstrated.

CONCLUSIONS

CXCR2 expression is significantly down-regulated after bypass; in contrast, CXCR1 expression remains unchanged. In addition, whereas interleukin 8 is an important determinant of both CXCR1 and CXCR2 expression in vitro, it only correlates with CXCR2 and CD11b expression in vivo. This has implications in the search for antagonists against CXC chemokines and their receptors.

Tumor necrosis factor-alpha induces stress fiber formation through ceramide production: role of sphingosine kinase

Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory cytokine that activates several signaling cascades. We determined the extent to which ceramide is a second messenger for TNF-alpha-induced signaling leading to cytoskeletal rearrangement in Rat2 fibroblasts. TNF-alpha, sphingomyelinase, or C(2)-ceramide induced tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin, and stress fiber formation. Ly 294002, a phosphatidylinositol 3-kinase (PI 3-K) inhibitor, or expression of dominant/negative Ras (N17) completely blocked C(2)-ceramide- and sphingomyelinase-induced tyrosine phosphorylation of FAK and paxillin and severely decreased stress fiber formation. The TNF-alpha effects were only partially inhibited. Dimethylsphingosine, a sphingosine kinase (SK) inhibitor, blocked stress fiber formation by TNF-alpha and C(2)-ceramide. TNF-alpha, sphingomyelinase, and C(2)-ceramide translocated Cdc42, Rac, and RhoA to membranes, and stimulated p21-activated protein kinase downstream of Ras-GTP, PI 3-K, and SK. Transfection with inactive RhoA inhibited the TNF-alpha- and C(2)-ceramide-induced stress fiber formation. Our results demonstrate that stimulation by TNF-alpha, which increases sphingomyelinase activity and ceramide formation, activates sphingosine kinase, Rho family GTPases, focal adhesion kinase, and paxillin. This novel pathway of ceramide signaling can account for approximately 70% of TNF-alpha-induced stress fiber formation and cytoskeletal reorganization.

CXCR2 regulation of tumor necrosis factor-alpha adherence-dependent peroxide production is significantly diminished after severe injury in human neutrophils

BACKGROUND

Primed neutrophils are thought to play a key role in inflammatory pathology. We have shown though in vitro studies that interleukin (IL)-8 and growth-related oncogene-alpha (GROalpha) (CXCR2-specific chemokines) regulate the respiratory burst via the CXCR2 receptor. We have also shown in vivo, CXCR2 receptors are down-regulated in severely injured patients. Our hypothesis is that regulation of the respiratory burst by CXCR2 is lost after severe injury.

METHODS

Patient neutrophils were studied within 24 hours of admission to the hospital; excluded were severe head injury and patients with Injury Severity Score < 16. Patient and normal neutrophils were isolated by Ficoll-Hypaque centrifugation after dextran sedimentation. Neutrophils were plated with buffer, 50 nmol/L IL-8 or GROalpha on fibronectin-coated plates for 15 minutes, then stimulated with 10 ng/mL of TNFalpha. CXCR2 expression was measured by flow cytometry. Receptor function was assessed by calcium mobilization.

RESULTS

One female and 10 male patients with an average age of 37 +/- 3 and Injury Severity Score of 24 +/- 5 suffered blunt injury. CXCR2 showed a 32% +/- 7% loss, whereas CXCR1 showed 15% +/- 6% reduction. GROalpha stimulation of patient neutrophils showed 60% +/- 16% decrease in calcium mobilization, whereas IL-8 showed no decline. At 40 minutes, IL-8 and GROalpha significantly inhibited TNFalpha adherence-dependent peroxide production in normal neutrophils (35% +/- 4% and 45% +/- 3%, respectively; p < 0.05). Both IL-8 and GROalpha lost the ability to suppress the respiratory burst in severely injured patients, but GROalpha had a significantly greater loss of this suppression (p = 0.004).

CONCLUSION

IL-8 and GROalpha lose the ability to regulate the TNFalpha-induced respiratory burst. This may contribute to neutrophil dysregulation after injury and result in organ injury.

Cardiopulmonary bypass elicits a pro- and anti-inflammatory cytokine response and impaired neutrophil chemotaxis in neonatal pigs

BACKGROUND

Cardiopulmonary bypass (CPB) induces a systemic inflammatory response and organ dysfunction, especially in children. Plasma concentration of inflammatory markers are increased in response to the trauma of cardiac surgery and CPB. The aim of the present study was to investigate whether the CPB procedure in itself elicits increased levels of inflammatory markers in neonatal pigs.

METHODS

The inflammatory response was measured in piglets undergoing sternotomy alone (sham group, n=13) or sternotomy and CPB (n=14). Inflammatory mediators were measured at baseline and at fixed time-points during and after CPB. IL-8, IL-10 and TNF-alpha levels and C-reactive protein (CRP) concentrations were measured in plasma samples. Polymorphonuclear neutrophils (PMN) chemotaxis was measured ex vivo, and CD-18 expression using an immunofluorescence technique.

RESULTS

Immediately after the CPB procedure increased IL-8 levels were found in the CPB group, but not in sham operated animals (P=0.005). Simultaneously, a marked IL-10 response was measured in the CPB group. Concurrently, PMN chemotaxis decreased in CPB animals but not in the sham group (P=0.04). CD-18 expression and CRP levels were not significantly different between groups and TNF-alpha showed no changes in either group. The chemotactic response did not correlate with plasma IL-8 or IL-10, nor with CD-18 expression.

CONCLUSION

The CPB procedure elicited a systemic inflammatory response in terms of significantly elevated plasma levels of IL-8 and IL-10. Furthermore, a temporary and simultaneous decrease in PMN chemotaxis was observed immediately after CPB.

Interleukin-8 overexpression is present in pyoderma gangrenosum ulcers and leads to ulcer formation in human skin xenografts

Interleukin-8 (IL-8) is a potent chemotactic polypeptide for neutrophils. However, the role of this cytokine during inflammation remains unclear. Skin specimens from patients with pyoderma gangrenosum demonstrated IL-8 overexpression in skin ulcers, which suggests a role for IL-8 in the development of the disease. We therefore constructed a recombinant adenovirus expressing the complementary deoxyribonucleic acid encoding human IL-8 (IL-8/Ad5) that induces a 2000-fold increase in IL-8 expression of infected human fibroblasts in vitro. Human skin engrafted to severe combined immunodeficiency mice and then injected with the recombinant virus demonstrated erythema, an intense perivascular infiltration of neutrophils, and extravasation of erythrocytes after 8 hours. By 12 hours after injection, neutrophils had accumulated beneath the epidermis, which then necrotized, and one or more ulcers that remained for approximately 2 weeks were observed. Clinically and histologically, the ulcers resembled pyoderma gangrenosum. These clinical and experimental findings suggest an etiologic role of IL-8 in the pathogenesis of pyoderma gangrenosum.