Major injury induces increased production of interleukin-10 by cells of the immune system with a negative impact on resistance to infection

Digital twin mathematical models suggest individualized hemorrhagic shock resuscitation strategies

BACKGROUND

Optimizing resuscitation to reduce inflammation and organ dysfunction following human trauma-associated hemorrhagic shock is a major clinical hurdle. This is limited by the short duration of pre-clinical studies and the sparsity of early data in the clinical setting.

METHODS

We sought to bridge this gap by linking preclinical data in a porcine model with clinical data from patients from the Prospective, Observational, Multicenter, Major Trauma Transfusion (PROMMTT) study via a three-compartment ordinary differential equation model of inflammation and coagulation.

RESULTS

The mathematical model accurately predicts physiologic, inflammatory, and laboratory measures in both the porcine model and patients, as well as the outcome and time of death in the PROMMTT cohort. Model simulation suggests that resuscitation with plasma and red blood cells outperformed resuscitation with crystalloid or plasma alone, and that earlier plasma resuscitation reduced injury severity and increased survival time.

CONCLUSIONS

This workflow may serve as a translational bridge from pre-clinical to clinical studies in trauma-associated hemorrhagic shock and other complex disease settings.

Interactions and Trends of Interleukins, PAI-1, CRP, and TNF-α in Inflammatory Responses during the Perioperative Period of Joint Arthroplasty: Implications for Pain Management-A Narrative Review

Inflammation during the perioperative period of joint arthroplasty is a critical aspect of patient outcomes, influencing both the pathophysiology of pain and the healing process. This narrative review comprehensively evaluates the roles of specific cytokines and inflammatory biomarkers in this context and their implications for pain management. Inflammatory responses are initiated and propagated by cytokines, which are pivotal in the development of both acute and chronic postoperative pain. Pro-inflammatory cytokines play essential roles in up-regulating the inflammatory response, which, if not adequately controlled, leads to sustained pain and impaired tissue healing. Anti-inflammatory cytokines work to dampen inflammatory responses and promote resolution. Our discussion extends to the genetic and molecular influences on cytokine production, which influence pain perception and recovery rates post-surgery. Furthermore, the role of PAI-1 in modulating inflammation through its impact on the fibrinolytic system highlights its potential as a therapeutic target. The perioperative modulation of these cytokines through various analgesic and anesthetic techniques, including the fascia iliac compartment block, demonstrates a significant reduction in pain and inflammatory markers, thus underscoring the importance of targeted therapeutic strategies. Our analysis suggests that a nuanced understanding of the interplay between pro-inflammatory and anti-inflammatory cytokines is required. Future research should focus on individualized pain management strategies.

A combination of burn wound injury and Pseudomonas infection elicits unique gene expression that enhances bacterial pathogenicity

IMPORTANCE

The interaction between an underlying disease process and a specific pathogen may lead to the unique expression of genes that affect bacterial pathogenesis. These genes may not be observed during infection in the absence of, or with a different underlying process or infection during the underlying process with a different pathogen. To test this hypothesis, we used Nanostring technology to compare gene transcription in a murine-burned wound infected with P. aeruginosa. The Nanostring probeset allowed the simultaneous direct comparison of immune response gene expression in both multiple host tissues and P. aeruginosa in conditions of burn alone, infection alone, and burn with infection. While RNA-Seq is used to discover novel transcripts, NanoString could be a technique to monitor specific changes in transcriptomes between samples and bypass the additional adjustments for multispecies sample processing or the need for the additional steps of alignment and assembly required for RNASeq. Using Nanostring, we identified arginine and IL-10 as important contributors to the lethal outcome of burned mice infected with P. aeruginosa. While other examples of altered gene transcription are in the literature, our study suggests that a more systematic comparison of gene expression in various underlying diseases during infection with specific bacterial pathogens may lead to the identification of unique host-pathogen interactions and result in more precise therapeutic interventions.

Screening and identification of the core immune-related genes and immune cell infiltration in severe burns and sepsis

Severe burns often have a high mortality rate due to sepsis, but the genetic and immune crosstalk between them remains unclear. In the present study, the GSE77791 and GSE95233 datasets were analysed to identify immune-related differentially expressed genes (DEGs) involved in disease progression in both burns and sepsis. Subsequently, weighted gene coexpression network analysis (WGCNA), gene enrichment analysis, protein-protein interaction (PPI) network construction, immune cell infiltration analysis, core gene identification, coexpression network analysis and clinical correlation analysis were performed. A total of 282 common DEGs associated with burns and sepsis were identified. Kyoto Encyclopedia of Genes and Genomes pathway analysis identified the following enriched pathways in burns and sepsis: metabolic pathways; complement and coagulation cascades; legionellosis; starch and sucrose metabolism; and ferroptosis. Finally, six core DEGs were identified, namely, IL10, RETN, THBS1, FGF13, LCN2 and MMP9. Correlation analysis showed that some core DEGs were significantly associated with simultaneous dysregulation of immune cells. Of these, RETN upregulation was associated with a worse prognosis. The immune-related genes and dysregulated immune cells in severe burns and sepsis provide potential research directions for diagnosis and treatment.

Extracorporeal Blood Purification in Burns: For Whom, Why, and How?

Patients with serious thermal burn injuries require immediate and specialized care in order to minimize morbidity and mortality. Optimal fluid resuscitation, nutritional support, pulmonary care, burn wound care, and infection control practices represent key aspects of patient care in burn centers. When severely burned, the patient usually presents a systemic inflammatory response syndrome, soon balanced by a counter anti-inflammatory response syndrome. These may lead to immune dysregulation/exhaustion favoring infectious complications that dramatically impair the prognosis of burn patients. This narrative review provides an overview of the main concepts, current understanding, and potential applications of extracorporeal blood purification techniques for burn patient management. Current understanding of burn patients' immune responses is reported. Hypotheses and data on the potential value of immunoregulation are reviewed. Finally, how extracorporeal blood purification may be of interest in this specific population is discussed.

Innate Immune System Response to Burn Damage-Focus on Cytokine Alteration

In the literature, burns are understood as traumatic events accompanied by increased morbidity and mortality among affected patients. Their characteristic feature is the formation of swelling and redness at the site of the burn, which indicates the development of inflammation. This reaction is not only important in the healing process of wounds but is also responsible for stimulating the patient’s innate immune system. As a result of the loss of the protective ability of the epidermis, microbes which include bacteria, fungi, and viruses have easier access to the system, which can result in infections. However, the patient is still able to overcome the infections that occur through a cascade of cytokines and growth factors stimulated by inflammation. Long-term inflammation also has negative consequences for the body, which may result in multi-organ failure or lead to fibrosis and scarring of the skin. The innate immune response to burns is not only immediate, but also severe and prolonged, and some people with burn shock may also experience immunosuppression accompanied by an increased susceptibility to fatal infections. This immunosuppression includes apoptosis-induced lymphopenia, decreased interleukin 2 (IL-2) secretion, neutrophil storm, impaired phagocytosis, and decreased monocyte human leukocyte antigen-DR. This is why it is important to understand how the immune system works in people with burns and during infections of wounds by microorganisms. The aim of this study was to characterize the molecular pathways of cell signaling of the immune system of people affected by burns, taking into account the role of microbial infections.

Burn Injury Induces Intestinal Inflammatory Response Mediated by Th17 in Burn-Primed Endotoxemic Mice

Objective

This study aimed to elucidate the mechanism underlying the susceptibility to infection-related acute lung injury by focusing on the role of gut mucosal T-helper (Th) 17 cells that preferentially produce IL-17 with probiotics in a burn-primed endotoxemic mice model.

Methods

Mice were subjected to a 15% total body surface area third-degree burn. Survival from lethal lipopolysaccharide (LPS) administration (3 mg/kg) on 11th day post-burn was assessed in mice fed by chow with or without 1.2% Lactobacillus powder after burn injury. Lamina propria mononuclear cells were enzymatically isolated from the ileum removed on 11th day post-burn and incubated along with 1 μg/mL LPS or 10 μg/mL anti-CD3 antibody for 24 hours; subsequently, the following 7 cytokines were analyzed in the supernatant: IFN-γ, TNF-α, IL-2, IL-4, IL-6, IL-10, and IL-17.

Results

Lactobacillus treatment post-burn injury markedly improved survival after lethal endotoxemia in burn-primed mice (64.3% versus 21.4%, P = 0.03). The production of proinflammatory cytokines such as TNF-α, IL-6, and IL-17 by lamina propria mononuclear T-lymphocytes and macrophages including Th17 response was augmented by burn injury but decreased with Lactobacillus treatment after burn injury.

Conclusions

Th17- and Th17-mediated inflammatory responses in the gut mucosa may play a vital role, which could be attenuated by Lactobacillus treatment, in survival of lethal endotoxemia in burn-primed mice.

Scald Injury-Induced T Cell Dysfunction Can Be Mitigated by Gr1+ Cell Depletion and Blockage of CD47/CD172a Signaling

Infection is a common and severe complication of burn injury: Sepsis accounts for 47% of postburn mortality. Burn-induced T cell suppression likely contributes to the increased infection susceptibility in burn patients. However, little is known about the kinetics of T cell dysfunction after burn and its underlying mechanisms. In this study, we show in a murine scald injury model that T cell activation of both CD4⁺ and CD8⁺ T cells as well as T cell cytokine production is suppressed acutely and persistently for at least 11 days after burn injury. Purified T cells from scald-injured mice exhibit normal T cell functions, indicating an extrinsically mediated defect. We further show that T cell dysfunction after burn appears to be cell-to-cell contact dependent and can be ameliorated by depletion of myeloid-derived suppressor cells. These cells expand after burn injury, particularly a subset expressing the checkpoint inhibitor CD172a, and infiltrate germinal centers. Expression of CD172a appears to be driven by ingestion of immature reticulocytes. Immature reticulocytes are drastically increased in the spleen of scald mice and may contribute to immunosuppression through more direct mechanisms as well. Overall, our study newly identifies two cell populations, myeloid-derived suppressor cells and immature reticulocytes, as well as the CD47/CD172a-signaling pathways as mediators of T cell suppressors after burn and thus opens up new research opportunities in the search for new therapies to combat increased infection susceptibility and the associated morbidity and mortality in burn victims.

Successful Fixation of a Tuberculous Nonunion of the Humeral Shaft: A Case Report

CASE

A 48-year-old man from North Africa with a history of infection after fixation of a humeral fracture presented 8 years later with an infected nonunion. After operative debridement, Mycobacterium tuberculosis grew on culture. Following a 2-stage surgical procedure and medical management of the tuberculosis (TB), successful union had been achieved at the 1-year follow-up.

CONCLUSION

Nonunion of the humerus caused by TB is a rare entity, but careful attention to patient demographics can forewarn the care provider. Irrigation and debridement with the Masquelet technique followed by compression plating and an iliac crest autograft can provide positive results.

Donor white blood cell survival and cytokine profiles following red blood cell transfusion in Australian major trauma patients

BACKGROUND

The potential for the co-existence of genetically disparate cells (microchimerism) and associated cytokine profiles following red blood cell (RBC) transfusion in trauma patients has not been well characterized to date. This study investigated the incidence of surviving donor white blood cells (known as transfused-associated microchimerism (TAM)) and cytokine changes following blood transfusion in trauma patients.

STUDY DESIGN AND METHODS

Trauma patients with an injury severity score (ISS) >12 who had been transfused between 2012-2016 with at least 5 units of RBC units over a 4 h period were recruited. Trauma patients with ISS > 12 who did not require blood transfusion were recruited as controls. The incidence of TAM was determined using a panel of insertion/deletion (InDel) bi-allelic polymorphisms. Selected pro- and anti-inflammatory cytokine profiles were analyzed using cytometric bead array.

RESULTS

The transfused cohort (n = 40) had median ISS of 28 [12-66], received a median of 11 RBC units [4-114] and had median hospital length of stay of 35 days [1-152]. Only 11 (27.5%) patients returned for follow-up blood sampling after discharge. Of these, one patient showed an InDel pattern indicating the presence of TAM. No patients in the control cohort (n = 49) showed TAM. Cytokines IL-10 and IL-6 were found to be elevated in the transfused trauma patients.

CONCLUSION

In this cohort, TAM was found to occur in one patient of the 11 who received a blood transfusion. Elevated IL-6 and IL-10 cytokines were detected in those patients who were transfused. However, the incidence of TAM could not be correlated with the elevated cytokine profiles for this cohort.

The time-course of the inflammatory response to major burn injury and its relation to organ failure and outcome

Burn injury causes major inflammatory activation and cytokine release, however, the temporal resolution of the acute and sub-acute inflammatory response has not yet been fully delineated. To this end, we have quantified 20 inflammatory mediators in plasma from 44 adult patients 0-21 days after burn injury and related the time course of these mediators to % total body surface area (TBSA) burned, clinical parameters, organ failure and outcome. Of the cytokines analyzed in these patients, interleukin 6 (IL-6), IL-8, IL-10 and monocyte chemoattractant protein 1 (MCP-1) correlated to the size of the injury at 24-48h after burn injury. In our study, the concentration of IL-10 had prognostic value in patients with burn injury both measured at admission and at 24-48h after injury. However, simple demographic data such as age, % burned TBSA, inhalation injury and their combination, the Baux score and modified Baux score, outperform most of the cytokines, with the exception of IL-8 and MCP-1 levels on admission, in predicting death.

Severity of Systemic Inflammatory Response Syndrome Affects the Blood Levels of Circulating Inflammatory-Relevant MicroRNAs

The systemic inflammatory response syndrome (SIRS) is a potentially lethal response triggered by diverse forms of tissue injury and infection. When systemic inflammation is triggered by infection, the term sepsis is used. Understanding how inflammation is mediated and regulated is of enormous medical importance. We previously demonstrated that circulating inflammatory-relevant microRNAs (CIR-miRNAs) are candidate biomarkers for differentiating sepsis from SIRS. Here, we set out to determine how CIR-miRNA levels reflect SIRS severity and whether they derive from activated immune cells. Clinical disease severity scores and markers of red blood cell (RBC) damage or immune cell activation were correlated with CIR-miRNA levels in patients with SIRS and sepsis. The release of CIR-miRNAs modulated during SIRS was assessed in immune cell cultures. We show that severity of non-infective SIRS, but not sepsis is reflected in the levels of miR-378a-3p, miR-30a-5p, miR-30d-5p, and miR-192-5p. These CIR-miRNA levels positively correlate with levels of the redox biomarker, peroxiredoxin-1 (Prdx-1), which has previously been shown to be released by immune cells during inflammation. Furthermore, in vitro activated immune cells produce SIRS-associated miR-378a-3p, miR-30a-5p, miR-30d-5p, and miR-192-5p. Our study furthers the understanding of the origin, role, and trafficking of CIR-miRNAs as potential regulators of inflammation.

Increased serum NKG2D-ligands and downregulation of NKG2D in peripheral blood NK cells of patients with major burns

Immune suppression following major thermal injury directly impacts the recovery potential. Limited data from past reports indicate that natural killer cells might be suppressed due to a putative soluble factor that has remained elusive up to date. Here we comparatively study cohorts of patients with Major and Non-Major Burns as well as healthy donors. MICB and ULBP1 are stress ligands of NKG2D that can be induced by heat stress. Remarkably, serum concentration levels of MICB and ULBP1 are increased by 3-fold and 20-fold, respectively, already within 24h post major thermal injury, and are maintained high for 28 days. In contrast, milder thermal injuries do not similarly enhance the serum levels of MICB and ULBP1. This kinetics coincides with a significant downregulation of NKG2D expression among peripheral blood NK cells. Downregulation of NKG2D by high concentration of soluble MICB occurs in cancer patients and during normal pregnancy due to over production by cancer cells or extravillous trophoblasts, respectively, as an active immune-evasion mechanism. In burn patients this seems an incidental outcome of extensive thermal injury, leading to reduced NKG2D expression. Enhanced susceptibility of these patients to opportunistic viral infections, particularly herpes viruses, could be explained by the reduced NKG2D expression. Further studies are warranted for translation into innovative diagnostic or therapeutic technologies.

Invited review: Compartmentalization of the inflammatory response in sepsis and SIRS

Sepsis and systemic inflammatory response syndrome (SIRS) are associated with an exacerbated production of both pro- and anti-inflammatory mediators that are mainly produced within tissues. Although a systemic process, the pathophysiological events differ from organ to organ, and from organ to peripheral blood, leading to the concept of compartmentalization. The nature of the insult ( e.g. burn, hemorrhage, trauma, peritonitis), the cellular composition of each compartment ( e.g . nature of phagocytes, nature of endothelial cells), and its micro-environment ( e.g. local presence of granulocyte-macrophage colony stimulating factor [GM-CSF] in the lungs, low levels of arginine in the liver, release of endotoxin from the gut), and leukocyte recruitment, have a great influence on local inflammation and on tissue injury. High levels of pro-inflammatory mediators ( e.g. interleukin-1 [IL-1], tumor necrosis factor [TNF], gamma interferon [IFN-γ], high mobility group protein-1 [HMGB1], macrophage migration inhibitory factor [MIF]) produced locally and released into the blood stream initiate remote organ injury as a consequence of an organ cross-talk. The inflammatory response within the tissues is greatly influenced by the local delivery of neuromediators by the cholinergic and sympathetic neurons. Acetylcholine and epinephrine contribute with IL-10 and other mediators to the anti-inflammatory compensatory response initiated to dampen the inflammatory process. Unfortunately, this regulatory response leads to an altered immune status of leukocytes that can increase the susceptibility to further infection. Again, the nature of the insult, the nature of the leukocytes, the presence of circulating microbial components, and the nature of the triggering agent employed to trigger cells, greatly influence the immune status of the leukocytes that may differ from one compartment to another. While anti-inflammatory mediators predominate within the blood stream to avoid igniting new inflammatory foci, their presence within tissues may not always be sufficient to prevent the initiation of a deleterious inflammatory response in the different compartments.

Interferon-γ counteracts reduced endotoxin responsiveness of whole blood following trauma and cardiopulmonary bypass

Accidental as well as surgical trauma has been reported to cause reduced endotoxin responsiveness of blood in terms of cytokine production. In this study, the effect of interferon-γ (IFN-γ) on tumour necrosis factor-α (TNF-α)-producing capacity of whole blood after severe trauma and cardiac surgery was investigated. Blood samples of severely injured patients were collected at the first day after trauma and of cardiac surgery patients before, 4 h and 2 days after cardiopulmonary bypass (CPB). The blood samples were incubated with INF-γ (0—100 U/ml) for 20 h and subsequently lipopolysaccharide (LPS)-induced TNF-α production was determined. Compared to healthy donors, LPS-induced TNF-α production was significantly reduced in blood cultures of trauma patients on day 1 after trauma and 4 h after CPB. Pre-incubation with IFN-γ in vitro increased endotoxin-induced TNF-α production in volunteers' and all patients' blood specimens in a dose-dependent manner. IFN-γ prompted an elevation of cytokine synthesis in CPB patients' blood which equalled that of volunteers, whereas it caused a lower rise in TNF-α production in blood of multiply injured patients, reaching levels of untreated donors only after incubation with 100 U/ml IFN-γ. These experiments show that hyporesponsiveness of whole blood induced by trauma or cardiac surgery with CPB is not irreversible, but can be counteracted by the immunostimulant IFN-γ. IFN-γ, therefore, could be applied clinically in trauma patients or after cardiac surgery to prevent or to resolve infection complications.

Contribution of programmed cell death receptor (PD)-1 to Kupffer cell dysfunction in murine polymicrobial sepsis

Recent studies suggest that coinhibitory receptors appear to be important in contributing sepsis-induced immunosuppression. Our laboratory reported that mice deficient in programmed cell death receptor (PD)-1 have increased bacterial clearance and improved survival in experimental sepsis induced by cecal ligation and puncture (CLP). In response to infection, the liver clears the blood of bacteria and produces cytokines. Kupffer cells, the resident macrophages in the liver, are strategically situated to perform the above functions. However, it is not known if PD-1 expression on Kupffer cells is altered by septic stimuli, let alone if PD-1 ligation contributes to the altered microbial handling seen. Here we report that PD-1 is significantly upregulated on Kupffer cells during sepsis. PD-1-deficient septic mouse Kupffer cells displayed markedly enhanced phagocytosis and restoration of the expression of major histocompatibility complex II and CD86, but reduced CD80 expression compared with septic wild-type (WT) mouse Kupffer cells. In response to ex vivo LPS stimulation, the cytokine productive capacity of Kupffer cells derived from PD-1-/- CLP mice exhibited a marked, albeit partial, restoration of the release of IL-6, IL-12, IL-1β, monocyte chemoattractant protein-1, and IL-10 compared with septic WT mouse Kupffer cells. In addition, PD-1 gene deficiency decreased LPS-induced apoptosis of septic Kupffer cells, as indicated by decreased levels of cleaved caspase-3 and reduced terminal deoxynucleotidyl transferase dUTP nick end-labeling-positive cells. Exploring the signal pathways involved, we found that, after ex vivo LPS stimulation, septic PD-1-/- mouse Kupffer cells exhibited an increased Akt phosphorylation and a reduced p38 phosphorylation compared with septic WT mouse Kupffer cells. Together, these results indicate that PD-1 appears to play an important role in regulating the development of Kupffer cell dysfunction seen in sepsis.

Neutrophil-Related Inflammatory Mediators in Septic Acute Respiratory Distress Syndrome

To disclose the participation of neutrophils in septic acute respiratory distress syndrome (ARDS), characteristics of various inflammatory mediators were examined in septic patients. Forty-seven gram-negative septic patients were divided into ARDS (n = 23) and non-ARDS (n = 24) groups at the transferred point to the intensive care unit. The mediators were measured simultaneously at the transferred point, and then subsequently on days 1, 3, and 5. At the transferred point, the ARDS group showed significantly higher levels of interleukin-8 (IL-8), macrophage inflammatory peptide-1-alpha (MIP-1-α), soluble intercellular adhesion molecule-1 (sICAM-1), and neutrophil elas-tase despite lower neutrophil counts compared to the non-ARDS group. The ARDS group sustained significantly higher levels of sICAM-1 until day 5 and neutrophil elas-tase until day 1 compare to the non-ARDS group. Furthermore, nonsurviving ARDS patients (n = 8) showed significantly higher levels of tumor necrosis factor-alpha, IL-6, IL-8, and IL-10 compared to surviving ARDS patients (n = 15) at the transferred point. In conclusion, neutrophil-related inflammatory mediators, IL-8, MIP-1-α, sICAM-1, and neutrophil elastase, appear to possibly participate in septic ARDS. Cytokines might also play an important role in the mortality of such cases.

Atypical Presentation of Tuberculosis of Elbow Joint in Operated Case of Distal Humerus Fracture

Introduction:

A typical presentations of tuberculosis are not uncommon. Periprosthetic infection with tuberculosis after total joint replacement has well published. Tuberculosis of the elbow following open reduction internal fixation of a distal humerus fraeture is extremely rare.

Case Report:

We report case of a healthy, immunocompetenet 49-year-old male who underwent open reduction and internal fixation with bicolumnar plating for distal humerus fracture and presented after 18 month with cystic swelling over medial aspect of operated site. There was no wound dehiscence and the underlying fracture was healed well without any signs of implant loosening or bony involvement. Cystic swelling was excised and histopathology provided the diagnosis of tuberculosis. Patient was treated with anti tubercular chemotherapy and patient made uneventful recovery.

Conclusion:

Although synovial tuberculosis after fracture fixation is a rare entity, tuberculosis should be kept as a differential diagnosis. Surgeons should have high index of suspicion to diagnose atypical presentations of tuberculosis.

Investigation the Possibility of Using Peptides with a Helical Repeating Pattern of Hydro-Phobic and Hydrophilic Residues to Inhibit IL-10

Blockade of IL-10 signalling clears chronic viral and bacterial infections. Immunization together with blockade of IL-10 signalling or relatively low level of IL-10 further enhances viral and bacterial clearance. IL-10 functions through binding to interleukin 10 receptor (IL-10R). Here we showed that peptides P1 and P2 with the hydrophobic and hydrophilic pattern of the IL10R-binding helix in IL-10 could bind with either IL-10R1 or IL-10, and inhibit inflammatory signals with long duration and negligible cytotoxicity in vitro. Furthermore, P2 can enhance antigen specific CD8+ T cell responses in mice induced by the vaccine based on a long peptide of protein E7 in a human papillomavirus type 16.

The Significance and Challenges of Monocyte Impairment: For the Ill Patient and the Surgeon

BACKGROUND

Trauma, major elective surgery, and overt sepsis can lead to a cascade of immunological change. A subset of these patients will have a degree of immune suppression that leads to hyporesponsive innate defenses, increasing the risk of infective co-morbidity and death. This article is an overview of monocyte impairment in the high-risk surgical patient. Specifically, our primary focus is on observations made pertaining to monocyte function and pathophysiological mechanisms underpinning this impairment. Clinical factors influencing monocyte function are also discussed.

METHODS

A Pubmed search was conducted to review aspects of monocyte impairment in the surgical patient. Search terms included "monocyte impairment," "immunoparalysis," and "endotoxin tolerance" cross-referenced against terms including "trauma," "major surgery," and "sepsis."

RESULTS

Findings revealed a broad variety of monocyte defects reported in surgical patients. They ranged from altered cytokine responses, particularly ex vivo TNF-α production, to impaired antigen presentation such as depressed HLA-DR expression. The latter is the most commonly described marker of secondary infection and death. Studies of underlying mechanisms have commonly utilized a model of endotoxin tolerance with in vitro monocytes, revealing a complex array of dysregulated pathways. For our purposes, endotoxin tolerance and monocyte impairment are sufficiently similar entities to permit further study as a single subject. In the high risk patient, microRNAs (also referred to as miRNA or miR) are emerging as potential biomarkers that may modify such pathways. Creation of a reliable impaired human monocyte model could be important to all such considerations.

CONCLUSION

Impairment of monocyte function continues to be predictive of nosocomial infection, multi-organ failure, and death in some surgical patients. However, the optimal marker that could identify a patient as high risk early enough, and whether it might guide potential therapy, still is yet to be proven.

The Effect of Perioperative Ischemia and Reperfusion on Multiorgan Dysfunction following Abdominal Aortic Aneurysm Repair

Abdominal aortic aneurysms (AAAs) are relatively common and are potentially life-threatening medical problems. The aim of this review is to provide an overview of the effect of I/R injury on multiorgan failure following AAA repair. The PubMed, CINAHL, EMBASE, Medline, Cochrane Review, and Scopus databases were comprehensively searched for articles concerning the pathophysiology of I/R and its systemic effects. Cross-referencing was performed using the bibliographies from the articles obtained. Articles retrieved were restricted to those published in English. One of the most prominent characteristics of AAA open repair is the double physiological phenomenon of ischemia-reperfusion (I/R) that happens either at the time of clamping or following the aortic clamp removal. Ischemia-reperfusion injury causes significant pathophysiological disturbances to distant organs, increasing the possibility for postoperative multiorgan failure. Although tissue injury is mediated by diverse mechanisms, microvascular dysfunction seems to be the final outcome of I/R.

Anti-Inflammatory Effect of Taurine in Burned Patients

PURPOSE

Burn induced inflammatory response can be mediated by reactive oxygen metabolites and accompanied by multiple organ dysfunction. Taurine has protective effects against various inflammatory conditions. The aim of this study was to determine the effect of Taurine supplement in thermal burn victims.

METHODS

Thirty patients with severe thermal burns were enrolled in this randomized double-blinded clinical trial. These patients were randomly divided into two equal groups (namely Control and Taurine groups), where both received isocaloric and isonitrogenous formula. One group was supplemented with 50 mg/kg of Taurine per day for a duration of 10 days. Blood samples were obtained to measure Interleukin-10 (IL-10), high-sensitivity C-reactive protein (hs-CRP), and Tumor Necrosis Factor alpha (TNF-α) levels at the beginning and the end of the study.

RESULTS

Change in serum level of IL-10 in Taurine group was more than Control group [-13.60(-31.40, -10.40) compared to -4.00(-20.00, -0.20) respectively; P = 0.030]. This change was significant in patients with more than 30% TBSA of burn [-14.20(-31.40, -10.40) compared to -2.40(-9.60, 0.40) respectively; P = 0.013]. As for the hs-CRP and TNF-α levels, the difference between the two groups were not significant.

CONCLUSION

Based on the results obtained, Taurine supplement showed a positive outcome on anti-inflammatory cytokine IL-10 in all burn patients. This effect was even more significant in patients with higher percentage of burn area. Taurine had no significant effect on the inflammatory marker hs-CRP and the pro-inflammatory cytokine TNF-α level. For a more thorough verification, measurement of a wider range of inflammatory cytokines in more frequent time intervals are suggested.

Improvement of prognostic performance in severely injured patients by integrated clinico-transcriptomics: a translational approach

Introduction

Severe trauma triggers a systemic inflammatory response that contributes to secondary complications, such as nosocomial infections, sepsis or multi-organ failure. The present study was aimed to identify markers predicting complications and an adverse outcome of severely injured patients by an integrated clinico-transcriptomic approach.

Methods

In a prospective study, RNA samples from circulating leukocytes from severely injured patients (injury severity score ≥ 17 points; n = 104) admitted to a Level I Trauma Center were analyzed for dynamic changes in gene expression over a period of 21 days by quantitative RT-PCR. Transcriptomic candidates were selected based on whole genome screening of a representative discovery set (n = 10 patients) or known mechanisms of the immune response, including mediators of inflammation (IL-8, IL-10, TNF-α, MIF, C5, CD59, SPHK1), danger signaling (HMGB1, TLR2, CD14, IL-33, IL-1RL1), and components of the heme degradation pathway (HP, CD163, HMOX1, BLVRA, BLVRB). Clinical markers comprised standard physiological and laboratory parameters and scoring systems routinely determined in trauma patients.

Results

Leukocytes, thrombocytes and the expression of sphingosine kinase-1 (SPHK1), complement C5, and haptoglobin (HP) have been identified as markers with the best performance. Leukocytes showed a biphasic course with peaks on day 0 and day 11 after trauma, and patients with sepsis exhibited significantly higher leukocyte levels. Thrombocyte numbers showed a typical profile with initial thrombopenia and robust thrombocytosis in week 3 after trauma, ranging 2- to 3-fold above the upper normal value. ‘Relative thrombocytopenia’ was associated with multi-organ dysfunction, the development of sepsis, and mortality, the latter of which could be predicted within 3 days prior to the time point of death. SPHK1 expression at the day of admission indicated mortality with excellent performance. C5-expression on day 1 after trauma correlated with an increased risk for the development of nosocomial infections during the later course, while HP was found to be a marker for the development of sepsis.

Conclusions

The combination of clinical and transcriptomic markers improves the prognostic performance and may represent a useful tool for individual risk stratification in trauma patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13054-015-1127-y) contains supplementary material, which is available to authorized users.

Implant-associated mycobacterium tuberculosis infection following surgical management of fractures: a retrospective observational study

In this retrospective observational cohort study, we describe 17 patients out of 1775 treated for various fractures who developed mycobacterium tuberculosis (MTB) infection after surgery. The cohort comprised 15 men and two women with a mean age of 40 years (24 to 70). A total of ten fractures were open and seven were closed. Of these, seven patients underwent intramedullary nailing of a fracture of the long bone, seven had fractures fixed with plates, two with Kirschner-wires and screws, and one had a hemiarthroplasty of the hip with an Austin Moore prosthesis. All patients were followed-up for two years. In all patients, the infection resolved, and in 14 the fractures united. Nonunion was seen in two patients one of whom underwent two-stage total hip arthroplasty (THA) and the other patient was treated using excision arthoplasty. Another patient was treated using two-stage THA. With only sporadic case reports in the literature, MTB infection is rarely clinically suspected, even in underdeveloped and developing countries, where pulmonary and other forms of TB are endemic. In developed countries there is also an increased incidence among immunocompromised patients. In this paper we discuss the pathogenesis and incidence of MTB infection after surgical management of fractures and suggest protocols for early diagnosis and management.

Inflammatory response to trauma: implications for coagulation and resuscitation

PURPOSE OF REVIEW

Recent studies have changed our understanding of the timing and interactions of the inflammatory processes and coagulation cascade following severe trauma. This review highlights this information and correlates its impact on the current clinical approach for fluid resuscitation and treatment of coagulopathy for trauma patients.

RECENT FINDINGS

Severe trauma is associated with a failure of multiple biologic emergency response systems that includes imbalanced inflammatory response, acute coagulopathy of trauma, and endovascular glycocalyx degradation with microcirculatory compromise. These abnormalities are all interlinked and related. Recent observations show that after severe trauma: proinflammatory and anti-inflammatory responses are concomitant, not sequential and resolution of the inflammatory response is an active process, not a passive one. Understanding these interrelated processes is considered extremely important for the development of future therapies for severe trauma in humans.

SUMMARY

Traumatic injuries continue to be a significant cause of mortality worldwide. Recent advances in understanding the mechanisms of end-organ failure, and modulation of the inflammatory response has important clinical implications regarding fluid resuscitation and treatment of coagulopathy.

Burn wound γδ T-cells support a Th2 and Th17 immune response

Major burn triggers immune dysfunction, which is associated with wound healing complications. Gamma-δ T-cells have been shown to be important in postburn inflammation and wound healing; however, their cytokine phenotype at the burn wound site is unknown. C57BL/6 male mice were subjected to a major burn (25% TBSA, third degree) or sham treatment. At 3 hours, 3 days, and 7 days thereafter, skin samples were collected and subjected to dispase and trypsin digestion to isolate single cells. The cells were phenotyped and evaluated for cytokine profiles by flow cytometry. Th1 cells were defined as interferon (IFN)γ positive, Th2 cells were defined as interleukin (IL)-10 positive, and Th17 cells were defined as IL-17 positive. At 7 days after burn a shift toward Th2 and Th17 positive T-cells at the wound site was observed. Further analysis revealed that at 3-hour postinjury the percentage of γδ T-cells positive for IFNγ, IL-10, and IL-17 were comparable between sham and burn skin samples. At 3 days and 7 days postinjury the percentage of cells positive for each cytokine increased; however, the increase was significantly greater for IL-10 and IL-17, as compared with IFNγ (ie, 9-20-fold vs 3-fold). Skin αβ T-cells preferentially produced IFNγ (~20%), which was unaffected by burn injury. These data demonstrate that burn wound γδ T-cells are activated for enhanced cytokine production and display a shift toward a Th2 and/or Th17 phenotype. In contrast, burn wound αβ T-cells were not activated for enhanced cytokine production.

Clinical recovery from surgery correlates with single-cell immune signatures

Delayed recovery from surgery causes personal suffering and substantial societal and economic costs. Whether immune mechanisms determine recovery after surgical trauma remains ill-defined. Single-cell mass cytometry was applied to serial whole-blood samples from 32 patients undergoing hip replacement to comprehensively characterize the phenotypic and functional immune response to surgical trauma. The simultaneous analysis of 14,000 phosphorylation events in precisely phenotyped immune cell subsets revealed uniform signaling responses among patients, demarcating a surgical immune signature. When regressed against clinical parameters of surgical recovery, including functional impairment and pain, strong correlations were found with STAT3 (signal transducer and activator of transcription), CREB (adenosine 3',5'-monophosphate response element-binding protein), and NF-κB (nuclear factor κB) signaling responses in subsets of CD14(+) monocytes (R = 0.7 to 0.8, false discovery rate <0.01). These sentinel results demonstrate the capacity of mass cytometry to survey the human immune system in a relevant clinical context. The mechanistically derived immune correlates point to diagnostic signatures, and potential therapeutic targets, that could postoperatively improve patient recovery.

Hydrogen sulfide [corrected] increases survival during sepsis: protective effect of CHOP inhibition

Sepsis is a major cause of mortality, and dysregulation of the immune response plays a central role in this syndrome. H2S, a recently discovered gaso-transmitter, is endogenously generated by many cell types, regulating a number of physiologic processes and pathophysiologic conditions. We report that H2S increased survival after experimental sepsis induced by cecal ligation and puncture (CLP) in mice. Exogenous H2S decreased the systemic inflammatory response, reduced apoptosis in the spleen, and accelerated bacterial eradication. We found that C/EBP homologous protein 10 (CHOP), a mediator of the endoplasmic reticulum stress response, was elevated in several organs after CLP, and its expression was inhibited by H2S treatment. Using CHOP-knockout (KO) mice, we demonstrated for the first time, to our knowledge, that genetic deletion of Chop increased survival after LPS injection or CLP. CHOP-KO mice displayed diminished splenic caspase-3 activation and apoptosis, decreased cytokine production, and augmented bacterial clearance. Furthermore, septic CHOP-KO mice treated with H2S showed no additive survival benefit compared with septic CHOP-KO mice. Finally, we showed that H2S inhibited CHOP expression in macrophages by a mechanism involving Nrf2 activation. In conclusion, our findings show a protective effect of H2S treatment afforded, at least partially, by inhibition of CHOP expression. The data reveal a major negative role for the transcription factor CHOP in overall survival during sepsis and suggest a new target for clinical intervention, as well potential strategies for treatment.

The effect of levamisole on mortality rate among patients with severe burn injuries

BACKGROUND

Burn injuries are one of the main causes of mortality and morbidity throughout the world and burn patients have higher chances for infection due to their decreased immune resistance. Levamisole, as an immunomodulation agent, stimulates the immune response against infection.

MATERIALS AND METHODS

This randomized clinical trial was conducted in Motahari Burn Center, Tehran, Iran. Patients who had second- or third-degree burn with involvement of more than 50% of total body surface area (TBSA) were studied. The levamisole group received levamisole tablet, 100 mg per day. Meantime, both the levamisole and control groups received the standard therapy of the Burn Center, based on a standard protocol. Then, the outcome of the patients was evaluated.

RESULTS

237 patients entered the study. After excluding 42 patients with inhalation injury, electrical and chemical burns, and the patients who died in the first 72 h, 195 patients remained in the study, including 110 patients in the control group and 85 in the treatment group. The mean age of all patients (between 13 to 64 years) was 33.29 ± 11.39 years (Mean ± SD), and it was 33.86 ± 11.45 years in the control group and 32.57 ± 11.32 years in the treatment group. The mean percentage of TBSA burn was 64.50 ± 14.34 and 68.58 ± 14.55 for the levamisole and control groups, respectively, with the range of 50-100% and 50-95% TBSA. The mortality rate was 68 (61.8%) patients in the control group and 50 (58.8%) patients in the treatment group (P = 0.8).

CONCLUSION

According to this study, there was no significant relationship between improvement of mortality and levamisole consumption.

Immunomodulation in transfused trauma patients

PURPOSE OF REVIEW

Traumatic injury is a major human health problem, with many injured people supported by transfusion of allogeneic blood. Although trauma and transfusion have both been known to have immunomodulatory effects for some time, little is known about their combined effects or the scope and kinetics of such responses.

RECENT FINDINGS

Traumatic injury has a profound immunomodulatory effect on the patient, affecting a broad array of immunological components. This can be further complicated by transfusion, though the contribution of transfusion relative to the massive response triggered by trauma is small. The response to trauma involves a strong immunosuppressive component, which, contrary to the systemic inflammatory response syndrome/compensatory anti-inflammatory response syndrome model, occurs at the earliest time points examined and overlaps with proinflammatory and antimicrobial elements. This response is remarkably similar in a wide range of patients with different types and severities of injury.

SUMMARY

The response to trauma and transfusion involves a massive and rapid reorganization of the immune system that can put the patient at increased risk of infection, tissue damage, and organ failure. The scope of the response presents challenges to the development of treatments to control this dysregulation.

Can mean platelet volume levels of trauma patients predict severity of trauma?

Abstract In this study, we aimed to evaluate the mean platelet voulme (MPV) levels of trauma patients who were admitted to our emergency department. Of the total 232 trauma patients, 40 females and 192 males over the age of 18 years were included in this study. Of them, 102 patients were mild trauma [Glasgow Coma Scale (GCS) 15-13)], 40 patients were moderate (GCS 12-9) and 90 patients were severe trauma (GCS 8-3) patients. We also calculated the Revised Trauma Score (RTS) of the patients. MPV levels were evaluated with GCS and RTS values. The control group was constituted of 100 healthy adults. Mean initial MPV value of GCS 15-13 patients was 8.25 fL, 8.25 fL in GCS 12-9 patients and 8.47 fL, in GCS 8-3 patients. Trauma severity was significantly related with initial MPV (iMPV) levels (p<0.05), initial Hb (iHb) levels (p<0.05), initial white blood count (iWBC) (p<0.05) and initial platelet (iPlt) levels (p<0.05). Severity of trauma was related with control MPV (kMPV) levels (p<0.05), control Hb (kHb) (p<0.05), control WBC (kWBC) (p<0.05), control Plt (kPlt) levels (p<0.05). MPV levels (p<0.05), Hb levels (p<0.05), WBC levels (p<0.05), Plt levels (p<0.05) were significantly different between trauma group and healthy group. IMPV and control kMPV levels were not related (p=0.149). But kHb - iHb levels (p<0.05), kWBC - iWBC levels (p<0.05), kPlt - iPlt levels (p<0.05), kGCS - iiGCS (p<0.05) were related to each other. We found a correlation between iMPV and iWBC levels (p<0.05, r=-0.342). Similarly, there was a correlation between severity of trauma and iMPV level (p<0.05, r=-0.224). We determined a significant correlation between iMPV and iPlt levels (p<0.05, r=-0.246). There was not a correlation between kMPV and kWBC (p>0.05, r=0.124). kMPV and kPlt levels (p<0.05, r=-0.174) were correlated. RTS was statistically related with GCS (p<0.05). Similarly, RTS was related with iMPV (p<0.05), iWBC(p<0.05) and iPlt (p<0.05) values, but there was not a relation with iHb (p>0.05). We found correlations between iMPV- trauma severity (p<0.05, r=-0.224), iMPV - RTS (p<0.05, r=0.134), iMPV - iWBC (p<0.05 r=-0.342), iMPV - iPlt (p<0.05, r=-0.246). Control RTS (seventh day of hospitalization) values were not related to kMPV (p>0.05), kHB (p>0.05), kWBC (p>0.05) and kPlt(p>0.05). There was a correlation between kRTS and kMPV (p<0.05, r=-0.169). Similarly, kMPV - kHb (p<0.05, r=-0.141), kMPV - kPlt (p<0.05, r=-0.174) were correlated. KMPV and kPlt were not correlated (p<0.05, r=0.124). Initial RTS and seventh day RTS values were significantly different (p<0.05). MPV may be helpful for emergency physicians for predicting the severity of trauma.

Skeletal Tuberculosis Following Proximal Tibia Fracture

Over the past several years, there has been a rise in incidence of tuberculosis in both developing and developed countries. Tuberculosis complicating a fracture is uncommon. In this article, we report the case of a 10-year-old patient with a proximal tibia fracture who developed discharging wound over the fracture site after 2 weeks of initial trauma. The fracture was showing no signs of healing. A diagnosis of tuberculosis of proximal tibia was made on the basis of polymerase chain reaction and histology. After antituberculous treatment was started, the sinus healed and the fracture united. To the best of our knowledge, such a presentation has not been documented.

Transfusion-associated microchimerism: the hybrid within

Microchimerism, the coexistence of genetically disparate populations of cells in a receptive host, is well described in both clinical and physiological settings, including transplantation and pregnancy. Microchimerism can also occur after allogeneic blood transfusion in traumatically injured patients, where donor cells have been observed decades after transfusion. To date, transfusion-associated microchimerism (TA-MC) appears confined to this clinical subset, most likely due to the immune perturbations that occur after severe trauma that allow foreign donor cells to survive. Transfusion-associated microchimerism appears to be unaffected by leukoreduction and has been documented after transfusion with an array of blood products. The only significant predictor of TA-MC to date is the age of red cells, with fresher units associated with higher risk. Thus far, no adverse clinical effect has been observed in limited studies of TA-MC. There are, however, hypothesized links to transfusion-associated graft vs host disease that may be unrecognized and consequently underreported. Microchimerism in other settings has gained increasing attention owing to a plausible link to autoimmune diseases, as well as its diagnostic and therapeutic potential vis-a-vis antenatal testing and adoptive immunotherapy, respectively. Furthermore, microchimerism provides a tool to further our understanding of immune tolerance and regulation.

Removal of increased circulating CD4+CD25+Foxp3+ regulatory T cells in patients with septic shock using hemoperfusion with polymyxin B-immobilized fibers

BACKGROUND

Although sepsis-induced immunosuppression has long been considered to be a factor in the late mortality of patients with sepsis, little is known about regulatory T cell (Treg)-mediated immunosuppression and the effect of polymyxin B-immobilized fiber (PMX-F) on sepsis-induced immunosuppression. We sought to investigate the role of CD4(+)CD25(+)Foxp3(+) Tregs in septic patients, and to evaluate the effect of hemoperfusion with PMX-F on the recovery from immunosuppression owing to septic shock.

METHODS

Thirty-two septic patients who had an identified focus of infection in the abdominal cavity were enrolled in this study. Peripheral blood mononuclear cells in the septic patients were examined to evaluate the roles of Tregs and the serum cytokine levels. We also examined the effects of PMX-F therapy on CD4(+) T cells, especially Tregs and serum cytokine levels in patients with septic shock.

RESULTS

The percentage of Tregs in the CD4(+) T-cell population, and the serum IL-6 and IL-10 levels, were significantly higher among patients with septic shock compared with those without septic shock, and PMX-F therapy significantly decreased the number of Tregs, as well as the serum IL-6 and IL-10 levels. Furthermore, a significant increase in the number of CD4(+) T cells, a significant decrease in the percentage of Tregs in the CD4(+) T-cell population, and a significant decrease in the serum IL-6 and IL-10 levels 24 hours after PMX-F therapy were observed in septic shock survivors compared with nonsurvivors.

CONCLUSION

We found a major increase in the percentage of Tregs in peripheral blood circulating CD4(+) T cells from patients with septic shock, and observed that the removal of Tregs by hemoperfusion with PMX-F might represent a novel strategy for inducing recovery from the immunosuppression associated with sepsis.

Distinct roles of trauma and transfusion in induction of immune modulation after injury

BACKGROUND

Trauma and transfusion can both alter immunity, and while transfusions are common among traumatically injured patients, few studies have examined their combined effects on immunity.

STUDY DESIGN AND METHODS

We tracked the plasma levels of 41 immunomodulatory proteins in 56 trauma patients from time of injury up to 1 year later. In addition, a murine model was developed to distinguish between the effects of transfusion and underlying injury and blood loss.

RESULTS

Thirty-one of the proteins had a significant change over time after traumatic injury, with a mixed early response that was predominantly anti-inflammatory followed by a later increase in proteins involved in wound healing and homeostasis. Results from the murine model revealed similar cytokine responses to humans. In mice, trauma and hemorrhage caused early perturbations in a number of the pro- and anti-inflammatory mediators measured, and transfusion blunted early elevations in interleukin (IL)-6, IL-10, matrix metalloproteinase-9, and interferon-γ. Transfusion caused or exacerbated changes in monocyte chemotactic protein-1, IL-1α, IL-5, IL-15, and soluble E-selectin. Finally, trauma and hemorrhage alone increased CXCL1 and IL-13.

CONCLUSIONS

This work provides a detailed characterization of the major shift in the immunologic environment in response to trauma and transfusion and clarifies which immune mediators are affected by trauma and hemorrhage and which by transfusion.

Neutralization of interleukin-10 or transforming growth factor-β decreases the percentages of CD4+ CD25+ Foxp3+ regulatory T cells in septic mice, thereby leading to an improved survival

OBJECTIVES

To investigate the role of CD4+ CD25+ Foxp3+ regulatory T cells (Tregs) in septic conditions, and to examine the potential of targeting them for the treatment of sepsis.

BACKGROUND

Sepsis-induced immunosuppression has long been considered a factor in late mortality of patients with sepsis. Although Tregs are central to the maintenance of immunologic homeostasis and tolerance, little is known about Treg-mediated immunosuppression in the late stages of sepsis.

METHODS

Peripheral blood mononuclear cells (MNCs) in septic patients and liver or spleen MNCs collected after a cecal ligation and puncture (CLP) model in C57BL/6 mice were examined to evaluate the roles of Tregs and the correlation of transforming growth factor (TGF)-β or interleukin (IL)-10 with their activity. We next examined the effects of neutralization of TGF-β or IL-10 on the percentages of Tregs in CD4+ T cells and the survival rates of septic mice.

RESULTS

The percentages of Tregs in peripheral blood lymphocytes were significantly increased in patients with sepsis, and there was a significantly positive correlation between serum IL-10 levels and the percentage of Tregs. CLP injury increases the percentages of Tregs in the CD4+ T cells in the spleen, and there was a significantly positive correlation between the percentages of Tregs and the serum IL-10 or TGF-β levels. The neutralization of TGF-β or IL-10 decreased the percentages of Tregs in CD4+ T cells, restored the percentages of CD4+ T cells in spleen MNCs, and improved survival rates in septic mice.

CONCLUSION

We found an increase in the percentages of Tregs in peripheral blood circulating CD4+ T cells from patients with sepsis, and in splenic MNCs from septic mice, and observed that regulation of Tregs by neutralizing IL-10 or TGF-β might represent a novel strategy for treating the immunosuppressive conditions in sepsis.

Elevated inflammatory mediators and pulmonary hypertension after applying an extracorporeal circuit in a neonatal sepsis model

PURPOSE

We aimed to study the changes in cytokines, oxidative mediators, and pulmonary blood pressure in a neonatal sepsis model when applying an extracorporeal circuit (ECC).

METHODS

Of 28 anesthetized and mechanically ventilated 3-day-old piglets, 14 underwent cecal ligation and perforation (CLP), of which 7 underwent ECC for 3 h from 3 to 6 h after CLP. The remaining 14 were sham, of which 7 underwent ECC. Serum interleukin (IL)-6, IL-10, tumor necrosis factor (TNF), interferon gamma (IFN-γ), total hydroperoxide (TH), nitric oxide metabolites (NOx), and mean pulmonary arterial blood pressure (mPAP)/mean arterial blood pressure (mABP) ratio were measured at pre-CLP and at 3, 6, and 9 h in the CLP groups, and continued in the sham groups at 12, 15, 18, and 24 h.

RESULTS

The CLP group with ECCs compared to the CLP group without it showed higher levels of serum IL-6, IL-10, and NOx at 6 h and higher levels of serum TH at 6 and 9 h. The sham group with ECCs compared to the one without it showed higher levels of serum IL-6 and IL-10 at 12, 15, and 18 h, TH at 6 and 9 h, TNF at 6 h, and IFN-γ at 9 h. The mPAP/mABP ratios in the CLP group with ECCs were higher compared to the CLP group without it at 6 and 9 h.

CONCLUSION

Applying ECCs provoked a window of cytokines, free radicals elevation, and pulmonary hypertension which could be hazardous in critically ill newborns.

Reprogrammed fibrocytes induce a mixed Th1/Th2 cytokine response of naïve CD4(+) T cells

Naïve CD4(+) T cells develop different effector T cells and cytokine profiles after antigenic stimulation. It has been previously documented that fibrocytes function as antigen presenting cells inducing proliferation as well as Th2 cytokine response in naïve CD4(+) T cells. Our group has reported that several circulating cell types recruited to the wound site can be transformed into anti-fibrotic profile cells, which subsequently induce MMP-1 stimulation in dermal fibroblasts. Here, we report how similar reprogramming pathway of fibrocytes could modify the CD4(+) T cell response. Our findings confirmed that reprogrammed fibrocytes induce CD4(+) T cell activation with a mixed Th1/Th2 cytokine response. Since a reciprocal positive feedback between Th2 cells and fibrocytes exist to amplify and perpetuate the pro-fibrotic stimulation in dermal fibroblasts, the novel transdifferentiation of regular mature fibrocytes into reprogrammed fibrocytes appears to be a promising strategy to reverse the Th2 cytokine overproduction, and subsequently control the local fibrogenesis.

Burn trauma induces early HMGB1 release in patients: its correlation with cytokines

High-mobility group box protein 1 (HMGB1) is a nuclear protein that may be released actively from monocytes and macrophages or passively from necrotic or damaged cells. Several experimental data suggest that burn injury is accompanied by elevated plasma HMGB, but there are only few data available about its changes in burned patients. The aim of this study was to follow the time course and the prognostic value of plasma HMGB1 and cytokine changes in patients with severe burn injury affecting more than 10% of body surface area (n = 26). Blood samples were taken on admission and on the following 5 days. Plasma HMGB1 concentration was measured by the enzyme-linked immunosorbent assay method, whereas IL-6, IL-8, and IL-10 were assayed by the cytometric bead array kit. The HMGB1 and IL-10 concentrations were elevated on admission and gradually decreased thereafter. Significant differences were observed between survivors and nonsurvivors in HMGB1 (P < 0.01) and IL-10 (P < 0.001) concentrations on admission with higher levels in nonsurvivors. IL-6 and IL-8 started to increase markedly from day 2. Positive correlation (r = 0.669, P < 0.01) was found between burned body surface and HMGB1 on admission. Receiver operating characteristic analysis of data on admission showed that at a level of 16 ng/mL, HMGB1 indicated lethality, with 75.0% sensitivity and 85.7% specificity. Using the cutoff level of 14 pg/mL, IL-10 predicted intensive care unit mortality, with 85.7% sensitivity and 84.2% specificity. Very early HMGB1 and IL-10 release may have an important impact on the immune function of patients after burn trauma.

Dendritic cell modification of neutrophil responses to infection after burn injury

Burn patients are highly susceptible to infections due to increased exposure through wounds and impairments in a number of immune functions. Dendritic cells (DCs) are important in activation of numerous immune responses that are essential for the clearance of infections. We have found that prophylactic treatment of burn-injured mice with the DC growth factor FLT3 ligand (FL) significantly increases resistance to burn wound infections in a DC-dependent manner that is correlated closely with enhanced bacterial clearance. However, as DCs are not typically microbicidal, the mechanisms by which DC modulation enhances bacterial clearance are not known. Due to the rapid response of neutrophils to cutaneous wounds, and the reported interactions between DCs and neutrophils, we investigated the role of neutrophils in FL-mediated resistance to burn wound infection. This was examined both in vivo and in vitro through neutrophil depletion, supplementation of neutrophils, and assessment of neutrophil chemotaxis following FL treatment. To test the involvement of DCs, CD11c-diphtheria toxin receptor transgenic mice were used to deplete DCs during FL treatment. Studies revealed that neutrophils do play a critical role in FL-mediated resistance to a burn wound infection. Additionally, treatment with FL after a burn injury enhances neutrophil-mediated control of bacterial spread, neutrophil migratory capacity, and myeloperoxidase production in a DC-dependent manner. The results of this study provide new insight into immunological mechanisms that can offer protection against infection after burn injury.

Selective effect of burn injury on splenic CD11c(+) dendritic cells and CD8alpha(+)CD4(-)CD11c(+) dendritic cell subsets

Burn injury causes an immunosuppression associated with suppressed adaptive immune function. Dendritic cells (DCs) are APCs for which signaling via their Toll-like receptors (TLRs) induces their maturation and activation, which is essential for the adaptive immune response. In this study, we examined if burn injury alters the TLR activity of splenic DCs. After injury, we noticed that DC functions were impaired, characterized by a suppressed capacity to prime naive T cells when triggering the TLR4 signaling cascade using specific ligands (LPS or rHSP60). The observed perturbations on LPS-primed DCs isolated from burned mice exhibited significantly diminished IL-12p40 production and enhanced IL-10 secretion-associated impairment in mitogen-activated protein kinase activation. Interestingly, we observed a decrease of TLR4/MD-2 expression on the CD8alpha(+) DC subset that persisted following LPS stimulation. The altered TLR4 expression on LPS-stimulated CD8alpha(+) DCs was associated with reduced capacity to produce IL-12 after stimulation. Our results suggested that TLR4 reactivity on DCs, especially CD8alpha(+) DCs, is disturbed after burn injury.

Pathophysiology of the systemic inflammatory response after major accidental trauma

Background

The purpose of the present study was to describe the pathophysiology of the systemic inflammatory response after major trauma and the timing of final reconstructive surgery.

Methods

An unsystematic review of the medical literature was performed and articles pertaining to the inflammatory response to trauma were obtained. The literature selected was based on the preference and clinical expertise of authors.

Discussion

The inflammatory response consists of hormonal metabolic and immunological components and the extent correlates with the magnitude of the tissue injury. After trauma and uncomplicated surgery a delicate balance between pro- and anti-inflammatory mediators is observed. Trauma patients are, however, often exposed, not only to the trauma, but to several events in the form of initial surgery and later final reconstructive surgery. In this case immune paralysis associated with increased risk of infection might develop. The inflammatory response is normalized 3 weeks following trauma. It has been proposed that the final reconstructive surgery should be postponed until the inflammatory response is normalized. This statement is however not based on clinical trials.

Conclusion

Postponement of final reconstructive surgery until the inflammatory is normalized should be based on prospective randomized trials.