Clinical evaluation of proinflammatory cytokine inhibitors (sTNFR I, sTNFR II, IL-1 ra), anti-inflammatory cytokines (IL-10, IL-13) and activation of neutrophils after burn-induced inflammation

Traumatic inflammatory response: pathophysiological role and clinical value of cytokines

Severe trauma is an intractable problem in healthcare. Patients have a widespread immune system response that is complex and vital to survival. Excessive inflammatory response is the main cause of poor prognosis and poor therapeutic effect of medications in trauma patients. Cytokines are signaling proteins that play critical roles in the body's response to injuries, which could amplify or suppress immune responses. Studies have demonstrated that cytokines are closely related to the severity of injuries and prognosis of trauma patients and help present cytokine-based diagnosis and treatment plans for trauma patients. In this review, we introduce the pathophysiological mechanisms of a traumatic inflammatory response and the role of cytokines in trauma patients. Furthermore, we discuss the potential of cytokine-based diagnosis and therapy for post-traumatic inflammatory response, although further clarification to elucidate the underlying mechanisms of cytokines following trauma is warranted.

Neutrophils and the Systemic Inflammatory Response Syndrome (SIRS)

We are not entirely able to understand, assess, and modulate the functioning of the immune system in clinical situations that lead to a systemic inflammatory response. In the search for diagnostic and treatment strategies (which are still far from perfect), it became very important to study the pathogenesis and participation of endogenous inflammation mediators. This study attempts to more precisely establish the role of neutrophils in individual phenomena occurring during an inflammatory and anti-inflammatory reaction, taking into account their cidal, immunoregulatory, and reparative abilities. Pro- and anticoagulatory properties of endothelium in systemic inflammatory response syndrome (SIRS) are emphasised, along with the resulting clinical implications (the application of immunotherapy using mesenchymal stem/stromal cells (MSCs) or IL-6 antagonists in sepsis and COVID-19 treatment, among others). Special attention is paid to reactive oxygen species (ROS), produced by neutrophils activated during "respiratory burst" in the course of SIRS; the protective and pathogenic role of these endogenous mediators is highlighted. Moreover, clinically useful biomarkers of SIRS (neutrophil extracellular traps, cell-free DNA, DAMP, TREMs, NGAL, miRNA, selected cytokines, ROS, and recognised markers of endothelial damage from the group of adhesins by means of immunohistochemical techniques) related to the neutrophils are presented, and their role in the diagnosing and forecasting of sepsis, burn disease, and COVID-19 is emphasised. Finally, examples of immunomodulation of sepsis and antioxidative thermal injury therapy are presented.

Early expression of IL-10, IL-12, ARG1, and NOS2 genes in peripheral blood mononuclear cells synergistically correlate with patient outcome after burn injury

BACKGROUND

No methods exist to rapidly and accurately quantify the immune insult created by burn injuries. The development of a rapid, noninvasive clinical biomarker assay that evaluates a burn patient's underlying immune dysfunction and predicts clinical outcomes could transform burn care. We aimed to determine a set of peripheral biomarkers that correlates with clinical outcomes of burn patients.

METHODS

This prospective observational study enrolled two patient cohorts within a single burn center into an institutionally approved institutional review board study. Blood draws were performed <48 hours after injury. Initial unbiased immune gene expression analysis compared 23 burn patients and 6 healthy controls using multiplex immune gene expression analysis of RNA from peripheral blood mononuclear cells. We then performed confirmatory outcomes analysis in 109 burn patients and 19 healthy controls using a targeted rapid quantitative polymerase chain reaction. Findings were validated and modeled associations with clinical outcomes using a regression model.

RESULTS

A total of 149 genes with a significant difference in expression from burn patients compared with controls were identified. Pathway analysis identified pathways related to interleukin (IL)-10 and inducible nitric oxide synthase signaling to have significant z scores. quantitative polymerase chain reaction analysis of IL-10, IL-12, arginase 1 (ARG1), and inducible nitric oxide synthase demonstrated that burn injury was associated with increased expression of ARG1 and IL-10, and decreased expression of nitric oxide synthase 2 (NOS2) and IL-12. Burn severity, acute lung injury, development of infection, failure of skin autograft, and mortality significantly correlated with expression of one or more of these genes. Ratios of IL-10/IL-12, ARG1/NOS2, and (ARG1-IL-10)/(NOS2-IL-12) transcript levels further improved the correlation with outcomes. Using a multivariate regression model, adjusting for patient confounders demonstrated that (ARG1-IL-10)/(NOS2-IL-12) significantly correlated with burn severity and development of acute lung injury.

CONCLUSION

We present a means to predict patient outcomes early after burn injury using peripheral blood, allowing early identification of underlying immune dysfunction.

LEVEL OF EVIDENCE

Prognostic/Epidemiological; Level II.

Respiratory Burst and TNF-α Receptor Expression of Neutrophils after Sepsis and Severe Injury-Induced Inflammation in Children

Systemic inflammatory response syndrome (SIRS) is defined as the systemic host response to infection or a non-infectious factor. The purpose of this study was to evaluate the involvement of reactive oxygen species (ROS) in severe inflammation and to assess the discrimination strength of the neutrophil BURSTTEST assay regarding its etiology in three groups of patients (sepsis, burns, and bone fractures) who met the SIRS criteria. The neutrophil activation (respiratory burst of granulocytes as well as p55 and p75 tumor necrosis factor (TNF-α) receptor expression) was evaluated twice using flow cytometry, and the results were compared with healthy controls and among SIRS subjects. A decreased oxygen metabolism in neutrophils after E.coli stimulation and increased TNF-α receptor expression were found in septic and burned patients on admission, while ROS production augmented and TNF-α receptor expression diminished with the applied therapy. The significant differences in neutrophil respiratory burst intensity among septic and burned patients and those with sepsis and bone fractures were found (however, there were not any such differences between patients with thermal and mechanical injuries). This study indicates that the neutrophil BURSTTEST evaluation might be a clinically reliable marker for differentiating the SIRS etiology.

Persistent Systemic Inflammation in Patients With Severe Burn Injury Is Accompanied by Influx of Immature Neutrophils and Shifts in T Cell Subsets and Cytokine Profiles

Severe burn injury causes local and systemic immune responses that can persist up to months, and can lead to systemic inflammatory response syndrome, organ damage and long-term sequalae such as hypertrophic scarring. To prevent these pathological conditions, a better understanding of the underlying mechanisms is essential. In this longitudinal study, we analyzed the temporal peripheral blood immune profile of 20 burn wound patients admitted to the intensive care by flow cytometry and secretome profiling, and compared this to data from 20 healthy subjects. The patient cohort showed signs of systemic inflammation and persistently high levels of pro-inflammatory soluble mediators, such as IL-6, IL-8, MCP-1, MIP-1β, and MIP-3α, were measured. Using both unsupervised and supervised flow cytometry techniques, we observed a continuous release of neutrophils and monocytes into the blood for at least 39 days. Increased numbers of immature neutrophils were present in peripheral blood in the first three weeks after injury (0.1–2.8 × 10⁶/ml after burn vs. 5 × 10³/ml in healthy controls). Total lymphocyte numbers did not increase, but numbers of effector T cells as well as regulatory T cells were increased from the second week onward. Within the CD4⁺ T cell population, elevated numbers of CCR4⁺CCR6^- and CCR4⁺CCR6⁺ cells were found. Altogether, these data reveal that severe burn injury induced a persistent innate inflammatory response, including a release of immature neutrophils, and shifts in the T cell composition toward an overall more pro-inflammatory phenotype, thereby continuing systemic inflammation and increasing the risk of secondary complications.

Mitochondrial Ca2+-activated K+ channels and their role in cell life and death pathways

Ca²⁺-activated K⁺ channels (K_Ca) are expressed at the plasma membrane and in cellular organelles. Expression of all K_Ca channel subtypes (BK, IK and SK) has been detected at the inner mitochondrial membrane of several cell types. Primary functions of these mitochondrial K_Ca channels include the regulation of mitochondrial ROS production, maintenance of the mitochondrial membrane potential and preservation of mitochondrial calcium homeostasis. These channels are therefore thought to contribute to cellular protection against oxidative stress through mitochondrial mechanisms of preconditioning. In this review, we summarize the current knowledge on mitochondrial KCa channels, and their role in mitochondrial function in relation to cell death and survival pathways. More specifically, we systematically discuss studies on the role of these mitochondrial K_Ca channels in pharmacological preconditioning, and according protective effects on ischemic insults to the brain and the heart.

Predictive Value of IL-8 for Sepsis and Severe Infections After Burn Injury: A Clinical Study

The inflammatory response induced by burn injury contributes to increased incidence of infections, sepsis, organ failure, and mortality. Thus, monitoring postburn inflammation is of paramount importance but, so far, there are no reliable biomarkers available to monitor and/or predict infectious complications after burn. As interleukin 8 (IL-8) is a major mediator for inflammatory responses, the aim of our study was to determine whether IL-8 expression can be used to predict postburn sepsis, infections, and mortality. Plasma cytokines, acute-phase proteins, constitutive proteins, and hormones were analyzed during the first 60 days after injury from 468 pediatric burn patients. Demographics and clinical outcome variables (length of stay, infection, sepsis, multiorgan failure [MOF], and mortality) were recorded. A cutoff level for IL-8 was determined using receiver operating characteristic analysis. Statistical significance is set at P < 0.05. Receiver operating characteristic analysis identified a cutoff level of 234 pg/mL for IL-8 for survival. Patients were grouped according to their average IL-8 levels relative to this cutoff and stratified into high (H) (n = 133) and low (L) (n = 335) groups. In the L group, regression analysis revealed a significant predictive value of IL-8 to percent of total body surface area burned and incidence of MOF (P < 0.001). In the H group, IL-8 levels were able to predict sepsis (P < 0.002). In the H group, elevated IL-8 was associated with increased inflammatory and acute-phase responses compared with the L group (P < 0.05). High levels of IL-8 correlated with increased MOF, sepsis, and mortality. These data suggest that serum levels of IL-8 may be a valid biomarker for monitoring sepsis, infections, and mortality in burn patients.

Hyper-inflammation and skin destruction mediated by rosiglitazone activation of macrophages in IL-6 deficiency

Injury initiates recruitment of macrophages to support tissue repair; however, excessive macrophage activity may exacerbate tissue damage causing further destruction and subsequent delay in wound repair. Here we show that the peroxisome proliferation–activated receptor-γ agonist, rosiglitazone (Rosi), a medication recently reintroduced as a drug to treat diabetes and with known anti-inflammatory properties, paradoxically generates pro-inflammatory macrophages. This is observed in both IL-6-deficient mice and control wild-type mice experimentally induced to produce high titers of auto-antibodies against IL-6, mimicking IL-6 deficiency in human diseases. IL-6 deficiency when combined with Rosi-mediated upregulation of suppressor of cytokine signaling 3 leads to an altered ratio of nuclear signal transducer and activator of transcription 3/NF-κB that allows hyper-induction of inducible nitric oxide synthase (iNOS). Macrophages activated in this manner cause de novo tissue destruction, recapitulating human chronic wounds, and can be reversed in vivo by recombinant IL-6, blocking macrophage infiltration, or neutralizing iNOS. This study provides insight into an unanticipated paradoxical role of Rosi in mediating hyper-inflammatory macrophage activation significant for diseases associated with IL-6 deficiency.

Gene expression profile of cytokines and receptors of inflammation from cultured keratinocytes of burned patients

INTRODUCTION

At all stages of wound healing, growth factors and cytokines play a particularly important role in the interaction with keratinocytes cellular receptors. Keratinocytes have received little attention about their potential to act as a source and target of cytokines. Changes in the cytokine levels after the burning occur prior to the metabolic abnormalities. Thus, it may be possible to develop therapeutic interventions that can mitigate the acute inflammatory response and modulating expression of these cytokines. The objective was to evaluate the expression of 84 genes mediators of the inflammatory response by using PCR array in a primary human epidermal cultured keratinocytes from patients with burns.

METHODS

Keratinocytes cultured from normal skin around injury from small and large burn patient were treated for DNA synthesis. The samples were analyzed by the PCR Superarray(®) assay and curve analyses were performed for 84 relevant human genes and their involvement in the inflammatory cytokines pathway and receptors. These genes were checked for the up or down regulation. And it was used MetaCore™ for the analysis of networks and Gene Ontology (GO) processes.

RESULTS

Chemokines of the CXC family were more expressed in the large burn group, except CXCL12. The C, CC and CX3C chemokine family were downregulated, especially in the small burn group. The interleukins IL8 and IL1B were more expressed in large burn than in small burn; except IL13RA1, IL13 and IL5RA that were downregulated, mainly in the small burn group.

CONCLUSIONS

The cytokine profile showed some important differences between the large and small burn patients, and from this original database, we can create new interventional trials in acute inflammation in burns.

A comparative analysis and systematic review of the wound-healing milieu: implications for body contouring after massive weight loss

BACKGROUND

Wound-healing complications following body contouring for massive weight loss patients are significant, with rates exceeding 40 percent. To better understand aberrant healing in this population, the authors have performed a comparative analysis of the wound milieu literature for patient populations with similar complication rates.

METHODS

PubMed and Ovid databases were reviewed from January of 1985 to January of 2009 for key terms, including wound healing, obesity, cancer, burn, transplant, and body contouring. Serum and wound levels of multiple factors, including matrix metalloproteinases (MMPs) and cytokines, were assessed.

RESULTS

Complication rates in body contouring surgery range from 31 to 66 percent. Sixty-five studies were reviewed, and wound-healing complication rates were identified for cancer (45.8 percent), burn (30.4 percent), posttransplant (36 percent), and obese (43 percent) populations. In these groups, matrix metalloproteinases and tissue inhibitors of metalloproteinase (TIMPs) help regulate wound repair. Matrix metalloproteinase levels were elevated in cancer (4-fold increase in MMP-2), burn (20- to 30-fold increase in MMP-9), transplant (1.4-fold increase in MMP-2), and obese/chronic (79-fold increase) populations. TIMPs were increased in cancer (1.9-fold increase in TIMP-2) and burn (1.4-fold increase in TIMP-1) patients but decreased in chronic wound (55-fold decrease in TIMP-1) populations. Alterations to these regulatory proteins lead to prolonged matrix degradation, up-regulation of inflammatory mediators, and decreased growth factors, delaying the wound-healing process.

CONCLUSIONS

Complications after body contouring surgery are likely multifactorial; however, molecular imbalances to the massive weight loss wound milieu may contribute to poor surgical outcomes. Examining wound regulatory proteins including transforming growth factor-beta, vascular endothelial growth factor, and matrix metalloproteinases could aid in understanding the healing difficulties observed clinically.