Do Alarmins Have a Role in Multiple Myeloma?

Objective: Calprotectin (CLP), S100A6, and high mobility group nucleosome-binding protein 1 (HMGN1), known as alarmins, are involved in the pathogenesis of many tumors. In this study, we aimed to investigate the relationships of serum CLP, S100A6, and HMGN1 levels with the clinical and laboratory findings of patients with multiple myeloma (MM) and their roles in the pathogenesis of MM. Materials and Methods: We measured the serum CLP, S100A6, and HMGN1 levels of 55 newly diagnosed patients and 32 healthy controls using the sandwich enzyme-linked immunosorbent assay method. The medical records of the patients were also reviewed. Results: Serum CLP, S100A6, and HMGN1 levels were significantly decreased in MM patients compared to the control group (p=0.012, p=0.001, and p=0.030, respectively). Receiver operating characteristic analysis was used to determine diagnostic cut-off values for serum CLP, S100A6, and HMGN1 of <98 ng/mL (area under the curve [AUC]: 0.663, 95% confidence interval [CI]: 0.554-0.761, p=0.009), <1174.5 pg/mL (AUC: 0.706, 95% CI: 0.598-0.799, p=0.001), and <440.18 pg/mL (AUC: 0.640, 95% CI: 0.530-0.740, p=0.03), respectively. CLP levels were found to be statistically significantly higher in patients with light chain MM (91.58±22.57 ng/mL) compared to heavy chain MM (79.42±15.83 ng/mL) (p=0.03). A negative correlation was observed between CLP and M protein, immunoglobulin G, globulin, and beta-2 microglobulin (correlation coefficients: -0.361, -0.370, -0.279, -0.300, respectively; p=0.024, p=0.06, p=0.04, p=0.0033). Conclusion: In this study, we found that serum CLP, S100A6, and HMGN1 levels were statistically lower in patients with newly diagnosed MM compared to the control group. These results suggest that CLP may bind to the paraprotein produced by heavy chain MM in the blood, causing its blood levels to be low. Additionally, low levels of HMGN1, which is involved in DNA repair, suggest that HMGN1 may contribute to the complex genetic abnormalities found in cases of MM.

Changes in serum DAMPs and cytokines/chemokines during near-infrared photoimmunotherapy for patients with head and neck cancer.

BACKGROUND: Near-infrared photoimmunotherapy (NIR-PIT) for head and neck cancer is a recently developed therapy. However, there is limited data on patients receiving NIR-PIT in real clinical settings. METHODS: Seven NIR-PIT sessions were administered to five patients with head and neck squamous cell carcinoma (HNSCC). Serum damage-associated molecular patterns (DAMPs) (HMGB1 and Hsp70 levels), and cytokine and chemokine production, were compared before and after NIR-PIT. RESULTS: The serum concentration of HMGB1 increased after NIR-PIT (p = 0.031, Wilcoxon test) in all patients except one who did not achieve a clinical response. Chemokines MIP-1α (CCL3) and MIP-1ß (CCL4) increased significantly 1-3 days after treatment (CCL3, p = 0.0036; CCL4, p = 0.0016, Wilcoxon test). A low pre-treatment neutrophil-to-lymphocyte ratio (NLR) was associated with a better response to therapy and survival. CONCLUSIONS: The release of DAMPs, and cytokine/chemokine production, were detected in the patients' peripheral blood. The baseline NLR may predict patient outcomes in response to NIR-PIT.

Danger-associated molecular pattern molecules and the receptor for advanced glycation end products enhance ANCA-induced responses.

OBJECTIVES: The pro-inflammatory activities of the calgranulins and HMGB1 can be counteracted by sRAGE, the soluble form of their shared receptor. To understand the role of these molecules in AAV and their potential as therapeutic targets we have studied (i) the relationship between these DAMPS and disease activity; (ii) the expression of RAGE and sRAGE in biopsy tissue and peripheral blood; and (iii) the effect of these molecules on ANCA-mediated cytokine production. METHODS: We examined circulating levels of calgranulins (S100A8/A9 and S100A12), HMGB1 and sRAGE by ELISA. RAGE was examined in AAV kidney and lung biopsies by immunohistochemistry and RAGE expression was monitored in peripheral blood by qPCR. In vitro, the effect of co-stimulating PBMC with ANCA and S100A8/A9 on cytokine production was studied by ELISA. RESULTS: We found significantly raised levels of calgranulins and HMGB1 in active AAV regardless of clinical phenotype (PR3+/MPO+ AAV). Levels of calgranulins showed significant correlations with each other. RAGE protein and message was raised in peripheral blood and in cells infiltrating kidney and lung biopsy tissue, while sRAGE was lowered. Furthermore, ANCA-mediated production of IL-8 from PBMC was significantly enhanced by the presence of S100A8/A9 in a RAGE/TLR4-dependent manner. CONCLUSIONS: Raised circulating calgranulins provide a good marker of disease activity in AAV and are unlikely to be counteracted by sRAGE. Increased RAGE expression in AAV indicates receptor stimulation in active disease that may exacerbate ANCA-induced cytokine production. Targeting the RAGE pathway may provide a useful therapeutic approach in AAV.

Combined rs-fMRI study on brain functional imaging and mechanism of RAGE-DAMPs of depression: Evidence from MDD patients to chronic stress-induced depression models in cynomolgus monkeys and mice.

More and more evidence show that major depressive disorder (MDD) is closely related to inflammation caused by chronic stress, which seriously affects human physical and mental health. However, the inflammatory mechanism of depression and its effect on brain function have not been clarified. Based on resting-state functional magnetic resonance imaging (rs-fMRI), we investigated change of brain functional imaging and the inflammatory mechanism of damage-related molecular patterns (DAMPs)-receptor of advanced glycation protein end product (RAGE) in MDD patients and depressive-like cynomolgus monkeys and mice models induced by chronic stress. The regional homogeneity (ReHo) and functional connectivity (FC) were analyzed using MATLAB and SPM12 software. We detected the expression of DAMPs-RAGE pathway-related proteins and mRNA in MDD peripheral blood and in serum and brain tissue of cynomolgus monkeys and mice. Meanwhile, RAGE gene knockout mice, RAGE inhibitor, and overexpression of AVV9RAGE adeno-associated virus were used to verify that RAGE is a reliable potential biomarker of depression. The results showed that the ReHo value of prefrontal cortex (PFC) in MDD patients and depressive-like cynomolgus monkeys was decreased. Then, the PFC was used as a seed point, the FC of ipsilateral and contralateral PFC were weakened in depressive-like mice. At the same time, qPCR showed that RAGE and HMGB1 mRNA were upregulated and S100ß mRNA was downregulated. The expression of RAGE-related inflammatory protein in PFC of depressive-like monkeys and mice were consistent with that in peripheral blood of MDD patients. Moreover, the results were confirmed in RAGE-/- mice, injection of FPS-ZM1, and overexpression of AAV9RAGE in mice. To sum up, our findings enhance the evidence that chronic stress-PFC-RAGE are associated with depression. These results attempt to establish the links between brain functional imaging, and molecular targets among different species will help to reveal the pathophysiological mechanism of depression from multiple perspectives.

Exosomes in Sepsis.

Sepsis is a severe state of infection with high mortality. Pathogen-associated molecular patterns and damage-associated molecular patterns (DAMPs) initiate dysregulated systemic inflammation upon binding to pattern recognition receptors. Exosomes are endosome-derived vesicles, which carry proteins, lipids and nucleic acids, and facilitate intercellular communications. Studies have shown altered contents and function of exosomes during sepsis. In sepsis, exosomes carry increased levels of cytokines and DAMPs to induce inflammation. Exosomal DAMPs include, but are not limited to, high mobility group box 1, heat shock proteins, histones, adenosine triphosphate, and extracellular RNA. Exosomes released during sepsis have impact on multiple organs, including the lungs, kidneys, liver, cardiovascular system, and central nervous system. Here, we review the mechanisms of inflammation caused by exosomes, and their contribution to multiple organ dysfunction in sepsis.

Elevated Plasma Levels of Mitochondria-Derived Damage-Associated Molecular Patterns during Liver Transplantation: Predictors for Postoperative Multi-Organ Dysfunction Syndrome.

The systemic cytokine response during surgery has been reported to be stimulated by the molecules released from damaged cells, called damage-associated molecular patterns (DAMPs). The relationship between DAMPs and liver transplantation has not been reported. We aimed to clarify the relationship between the plasma levels of DAMPs and the short-term post-transplant outcomes, including mortality and postoperative multi-organ dysfunction syndrome (MODS). This retrospective cohort study enrolled 61 patients who underwent liver transplantation. Mitochondrial DNA fragments, as mitochondria-derived DAMPs (mtDAMPs), were isolated from frozen plasma obtained at the start and the end of transplantation and were quantified by polymerase chain reaction. The short-term post-transplant outcomes were compared among the groups categorized based on the median value of the intraoperative fluctuation of mtDAMPs levels. The mtDAMPs levels were increased from the start to the end of transplantation in 52 recipients (85.2%, n = 61). Regarding mortality, no significant differences were noted between the high group (n = 30) and the low group (n = 31). The higher plasma levels of mtDAMPs were correlated with the longer duration of postoperative vasopressor support (P < 0.05). Importantly, the rate of MODS on post-operative day 1 was significantly higher in the high group (high vs. low group: 21 patients [70%] vs. 11 patients [35.1%], P < 0.01). In conclusion, mtDAMPs were increased in plasma during liver transplantation in most recipients. This elevation was not associated with mortality, but associated with the post-transplant recovery. Measuring plasma mtDAMPs may be helpful for predicting posttransplant recovery among liver-transplant recipients.

Cerium Nitrate Treatment Provides Eschar Stabilization through Reduction in Bioburden, DAMPs, and Inflammatory Cytokines in a Rat Scald Burn Model.

In this study, we used a clinically relevant rat scald burn model to determine the treatment effects of cerium nitrate (CN) for stabilizing burn eschars through reduction of damage-associated molecular patterns (DAMPs), inflammatory cytokines, and bioburden. Forty-two male Sprague-Dawley rats were anesthetized before undergoing a scald burn at 99°C for 6 seconds to create a 10% full-thickness burn. The test groups included sham burn, burn with water bathing, and burn with CN bathing. End point parameters included circulating DAMPs, proinflammatory cytokines, tissue myeloperoxidase activity, and quantification of resident flora in burn skin. The high mobility group protein box 1 was found to be elevated in burn animals at postoperative days (POD) 1 and 7. CN significantly alleviated the increase (P < .05 at POD 1 and P < .01 at POD 7). CN also lessened the heightened levels of hyaluronan in burn animals (P < .05 at POD 7). Additionally, CN significantly reduced the burn-induced increases in interleukin-1ß, growth-regulated oncogene/keratinocyte chemoattractant, and macrophage inflammatory protein-1α in burn wounds. The anti-inflammatory effect of CN was also demonstrated in its ability to mitigate the upregulated circulatory xanthine oxidase/dehydrogenase and increased tissue neutrophil infiltration in burn animals. Last, CN suppressed postburn proliferation of resident skin microbes, resulting in a significant 2-log reduction by POD 7. In conclusion, these results suggest that CN attenuates the burn-induced DAMPs, tissue inflammatory responses, and regrowth of resident skin flora, all of which collectively could improve the quality of burn eschar when applied at the point of injury in prolonged field care situations.

Targeted proteomics reveals serum amyloid A variants and alarmins S100A8-S100A9 as key plasma biomarkers of rheumatoid arthritis.

Serum amyloid A (SAA) and S100 (S100A8, S100A9 and S100A12) proteins were previously identified as biomarkers of interest for rheumatoid arthritis (RA). Among SAA family, two closely related isoforms (SAA-1 and SAA-2) are linked to the acute-phase of inflammation. They respectively exist under the form of three (α, ß, and γ) and two (α and ß) allelic variants. We developed a single run quantitative method for these protein variants and investigated their clinical relevance in the context of RA. The method was developed and validated according to regulations before being applied on plasma coming from RA patients (n = 46), other related inflammatory pathologies (n = 116) and controls (n = 62). Depending on the activity score of RA, SAA1 isoforms (mainly of SAA1α and SAA1ß subtypes) were found to be differentially present in plasma revealing their dual role during the development of RA. In addition, the weight of SAA1α in the total SAA response varied from 32 to 80% depending on the pathology studied. A negative correlation between SAA1α and SAA1ß was also highlighted for RA early-onset (r = -0.41). SAA2 and S100A8/S100A9 proteins were significantly overexpressed compared to control samples regardless of RA stage. The pathophysiological relevance of these quantitative and qualitative characteristics of the SAA response remains unknown. However, the significant negative correlation observed between SAA1α and SAA1ß levels in RA early-onset suggests the existence of still unknown regulatory mechanisms in these diseases.

The effects of acute hypoxia on tissue oxygenation and circulating alarmins in healthy adults.

The binding of high-mobility group box-1 (HMGB-1) to the membrane receptor for advanced glycation end-products (mRAGE) is a key early mediator of non-infectious inflammation and its triggers include ischaemia/hypoxia. The effects of acute hypoxia on soluble RAGE (sRAGE) are unknown. Fourteen healthy adults (50 % women; 26.6+/-3.8 years) were assessed at baseline normoxia (T0), followed by four time-points (T90, 95, 100 and 180 min) over three hours of continuous normobaric hypoxia (NH, 4,450 m equivalent) and again 60 min after return to normoxia (T240). A 5-min exercise step test was performed during NH at T90. Plasma concentrations of HMGB-1, sRAGE VCAM-1, ICAM-1, VEGF IL-8 and IL-13 were measured using venous blood. Arterial and tissue oxygen saturations were measured using pulse oximetry (SpO(2)) and near-infrared spectroscopy (StO(2)), respectively. NH led to a significant reduction in SpO(2), StO(2), sRAGE and VEGF, which was compounded by exercise, before increasing to baseline values with normoxic restoration (T240). NH-exercise led to a paired increase in HMGB-1. sRAGE inversely correlated with HMGB-1 (r=-0.32; p=0.006), heart rate (r=-0.43; p=0.004) but was not linked to SpO(2) or StO(2). In conclusion, short-term NH leads to a fall in sRAGE and VEGF concentrations with a transient rise post NH-exercise in HMGB-1.

Thrombomodulin, alarmin signaling, and copeptin: cross-talk between obesity and acute ischemic stroke initiation and severity in Egyptians.

Acute ischemic stroke (AIS) is followed by a strong inflammatory response contributing to brain damage and making early diagnosis and treatment inevitable. Hence, obesity is a state of chronic inflammation with amplified oxidative stress; this study aimed to assess the role played by thrombomodulin (TM)/alarmin signaling pathway and copeptin in AIS initiation and severity in addition to the implication of abnormal body weight. The study was conducted on 50 participants; 30 were patients with AIS (15 overweight/obese and 15 normal weight), 10 were overweight/obese, and 10 were normal weight. Plasma TM, copeptin, high mobility group box1 (HMGB1), and lipocalin 2 (LCN2) levels were immunoassayed. Toll-like receptor 4 (TLR4) mRNA expression was evaluated by real-time PCR, National Institutes of Health Stroke Scale (NIHSS), carotid intima media thickness; atherogenic index and glycemic status were also assessed. TM, copeptin, HMGB1, and LCN2 levels were significantly increased in overweight/obese AIS patients and in AIS patients with NIHSS score ≥ 7 when compared to other groups (p value=, ˂ 0.001*). Receiver operating characteristic (ROC) curve elaborated HMGB-1 and LCN2 as the best biomarker for diagnosis and prediction of AIS severity, respectively. Regression analysis avails LCN2 and TM as best biomarker for AIS severity predication. In conclusion, these results highlighted detrimental role of alarmin signaling with increased adaptive response to block this pathway through TM in addition to increased copeptin level as an acute damage marker and their tight relation to WC not to BMI in AIS which clarify the implication of central adiposity.

Increased Plasma Levels of Danger-Associated Molecular Patterns Are Associated With Immune Suppression and Postoperative Infections in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

Introduction: Danger-associated molecular patterns (DAMPs) can elicit immune responses and may subsequently induce an immune-suppressed state. Previous work showed that increased plasma levels of DAMPs are associated with immune suppression and increased susceptibility toward infections in trauma patients. Like trauma, major surgical procedures, such as cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC), are also thought to cause profound DAMP release. Furthermore, the incidence of postoperative infections in these patients, ranging from 10 to 36%, is very high compared to that observed in patients undergoing other major surgical procedures. We hypothesized that the double hit of surgical trauma (CRS) in combination with HIPEC causes excessive DAMP release, which in turn contributes to the development of immune suppression. To investigate this, we assessed DAMP release in patients undergoing CRS-HIPEC, and investigated its relationship with immune suppression and postoperative infections. Methods: In 20 patients undergoing CRS-HIPEC, blood was obtained at five time points: just before surgery (baseline), after CRS, after HIPEC, at ICU admission, and 1 day after surgery. Circulating levels of DAMPs [heat shock protein (HSP)70, high mobility group box (HMGB)1, S100A12, S100A8/S100A9, nuclear (n)DNA, mitochondrial (mt)DNA, lactate dehydrogenase (LDH), a marker of unscheduled cell death], and cytokines [tumor necrosis factor (TNF)α, IL-6, IL-8, IL-10, macrophage inflammatory protein (MIP)-1α, MIP-1ß, and MCP-1] were measured. The extent of immune suppression was determined by measuring HLA-DR gene expression and ex vivo leukocytic cytokine production capacity. Results: Plasma levels of DAMPs (maximum fold increases of HSP70: 2.1 [1.5-2.8], HMGB1: 5.9 [3.2-9.8], S100A8/S100A9: 3.6 [1.8-5.6], S100A12: 2.6 [1.8-4.3], nDNA 3.9 [1.0-10.8], LDH 1.7 [1.2-2.5]), and all measured cytokines increased profoundly following CRS-HIPEC. Evidence of immune suppression was already apparent during the procedure, illustrated by a decrease of HLA-DR expression compared with baseline (0.5-fold [0.3-0.9]) and diminished ex vivo pro-inflammatory cytokine production capacity. The increase in HMGB1 levels correlated with the decrease in HLA-DR expression (r = -0.46, p = 0.04), and peak HMGB1 concentrations were significantly higher in the five patients who went on to develop a postoperative infection (p = 0.04). Conclusion: CRS-HIPEC is associated with profound DAMP release and immune suppression, and plasma HMGB1 levels are related with the occurrence of postoperative infections in these patients.

Alarmins as biomarkers of gastrointestinal surgical injury - a pilot study.

The dysregulation of inflammatory response to surgical injury affects outcomes. Alarmins, the earliest bioactive substances from damaged cells, play a crucial role in initiating the inflammation. We analyzed serum levels of alarmins (S100A8, S100A12, high mobility group box, and heat shock protein 70) after major abdominal surgery (MAS) in surgical (S) (n = 82) and nonsurgical (NS) groups (n = 35). The main objective was determining a role of selected alarmins in host response to MAS. The secondary objectives were (i) evaluation of the relationship among alarmins and selected biomarkers (C-reactive protein, interleukin-6), (ii) influence of the place of gastrointestinal resection, and (iii) role of alarmins in MAS for cancer. Except for HMGB1, the levels of all alarmins were higher in the S group compared with the NS group. In the S group, positive correlations were found between S100A8 and both IL-6 and CRP. Additionally, the S100A8 level was higher (p < 0.01) in patients who underwent upper gastrointestinal tract (GIT) surgery compared to middle and lower GIT resections. Alarmins levels did not differ between cancer and noncancer patients. MAS is able to elicit increase in alarmin levels. S100A8 can be considered a potential biomarker of surgical injury, especially in the upper part of the GIT.

Effects of Changes in the Levels of Damage-Associated Molecular Patterns Following Continuous Veno-Venous Hemofiltration Therapy on Outcomes in Acute Kidney Injury Patients With Sepsis.

Background: We investigated the association of damage-associated molecular pattern (DAMP) removal with mortality in sepsis patients undergoing continuous veno-venous hemofiltration (CVVH). Methods: Circulating levels of DAMPs [mitochondrial DNA (mtDNA); nuclear DNA (nDNA); heat shock protein 70 (HSP70); and high mobility group box 1 (HMGB1)] and cytokines were measured at baseline, 6 and 12 h after initiation of CVVH. Urinary DNA levels were analyzed at baseline and end of CVVH. The expression of human leukocyte antigen (HLA)-DR was assayed at 0, 3, and 7 days after initiation of CVVH. Moreover, the effects of HSP70 and HMGB1 clearance on survival were analyzed. Results: We evaluated 43 patients with acute kidney injury (AKI) (33 sepsis patients). Twenty-two sepsis patients (67%) and three non-sepsis patients (30%) expired (P = 0.046). Significant reductions in the levels of circulating interleukin-6 (P = 0.046) and tumor necrosis factor-α (P = 0.008) were found in the sepsis group. The levels of mtDNA were increased (ND2, P = 0.035; D-loop, P = 0.003), whereas that of HSP70 was reduced (P = 0.000) in all patients during the first 12 h. The levels of DAMPs in the plasma were markedly increased after blood passage from the inlet through the dialyzer in survivor sepsis patients. The clearance rates of HSP70 and HMGB1 were good predictors of mortality [area under the curve (AUC) = 0.937, P = 0.000; AUC = 0.90, P = 0.001, respectively]. The level of HLA-DR was increased in response to higher HSP70 clearance (P = 0.006). Survival was significantly worse in groups with higher clearance rates of HSP70 and HMGB1 than the cut-off value (log-rank test: P = 0.000 for both). Higher HSP70 clearance was a significant independent predictor of mortality (odds ratio = 1.025, 95% confidence interval [CI]: 1.012-1.039, P = 0.000). The urinary nDNA (ß-globin) level before CVVH was an independent risk factor for the duration of CVVH in patients with sepsis (sRE = 0.460, 95% CI: 1.720-8.857, P = 0.005). Conclusion: CVVH removes inflammatory factors, reduces urinary DAMPs, and removes plasma DAMPs. However, survival decreases in response to higher HSP70 clearance.

Extracellular nucleic acids in immunity and cardiovascular responses: between alert and disease.

Severe inflammatory complications are a potential consequence in patients with predetermined conditions of infections, pulmonary diseases, or cardiovascular disorders. Notably, the amplitude of the inflammatory response towards these complications can dictate the disease progression and outcome. During the recent years, evidence from basic research as well as from clinical studies has identified self-extracellular nucleic acids as important players in the crosstalk between immunity and cardiovascular diseases. These stress- or injury-induced endogenous polymeric macromolecules not only serve as "alarmins" or "Danger-associated molecular patterns" (DAMPs), but their functional repertoire goes far beyond such activities in innate immunity. In fact, (patho-) physiological functions of self-extracellular DNA and RNA are associated and in many cases causally related to arterial and venous thrombosis, atherosclerosis, ischemia-reperfusion injury or tumour progression. Yet, the underlying molecular mechanisms are far from being completely understood. Interestingly enough, however, novel antagonistic approaches in vitro and in vivo, particularly using natural endonucleases or synthetic nucleic acid binding polymers, appear to be promising and safe therapeutic options for future studies. The aim of this review article is to provide an overview of the current state of (patho-) physiological functions of self-extracellular nucleic acids with special emphasis on their role as beneficial / alerting or adverse / damaging factors in connection with immune responses, inflammation, thrombosis, and cardiovascular diseases.

Damage-associated molecular patterns (DAMPs) released after burn are associated with inflammation and monocyte activation.

Burns are associated with activation of the innate immunity that can contribute to complications. Damage-associated molecular patterns (DAMPs) released after tissue injury play a critical role in the activation of the innate immunity, which appears to be mediated via toll-like receptors (TLRs). Previous findings have shown that TLRs and TLR-mediated responses are up-regulated after burn. Nonetheless, it is unclear what impact burn has on circulating levels of DAMPs. To study this, male C57BL/6 mice were subjected to a major burn or sham procedure. Three hours to 7days thereafter, plasma was collected and assayed for the representative DAMPs (i.e., HMGB1, cytochrome C, DNA and S100A) and extracellular cleavage products (fibronectin and hyaluronan). HMGB1, cytochrome C, fibronectin and hyaluronan levels were elevated in a time-dependent manner after burn as compared to sham levels. A significant elevation in TNF-α, IL-6 and IL-10 cytokine plasma levels was also found after burn. All cytokine levels were increased as early as 3h and remained elevated up to 24h. Circulating CD11b+ monocytes were increased at 24h after burn and showed increased expression of TLR-2. In conclusion, these findings support the concept that burn-induced elevations in circulating DAMPs are in part responsible for monocyte activation and the development of inflammatory complications under such conditions and warrants further investigation.

Potential contribution of mitochondrial DNA damage associated molecular patterns in transfusion products to the development of acute respiratory distress syndrome after multiple transfusions.

BACKGROUND: Massive transfusions are accompanied by an increased incidence of a particularly aggressive and lethal form of acute lung injury (delayed transfusion-related acute lung injury) which occurs longer than 24 hours after transfusions. In light of recent reports showing that mitochondrial (mt)DNA damage-associated molecular patterns (DAMPs) are potent proinflammatory mediators, and that their abundance in the sera of severely injured or septic patients is predictive of clinical outcomes, we explored the idea that mtDNA DAMPs are present in transfusion products and are associated with the occurrence of delayed transfusion-related acute lung injury. METHODS: We prospectively enrolled fourteen consecutive severely injured patients that received greater than three units of blood transfusion products and determined if the total amount of mtDNA DAMPs delivered during transfusion correlated with serum mtDNA DAMPs measured after the last transfusion, and whether the quantity of mtDNA DAMPs in the serum-predicted development of acute respiratory distress syndrome (ARDS). RESULTS: We found detectable levels of mtDNA DAMPs in packed red blood cells (3 ± 0.4 ng/mL), fresh frozen plasma (213.7 ± 65 ng/mL), and platelets (94.8 ± 69.2), with the latter two transfusion products containing significant amounts of mtDNA fragments. There was a linear relationship between the mtDNA DAMPs given during transfusion and the serum concentration of mtDNA fragments (R = 0.0.74, p < 0.01). The quantity of mtDNA DAMPs in serum measured at 24 hours after transfusion predicted the occurrence of ARDS (9.9 ± 1.4 vs. 3.3 ± 0.9, p < 0.01). CONCLUSION: These data show that fresh frozen plasma and platelets contain large amounts of extracellular mtDNA, that the amount of mtDNA DAMPs administered during transfusion may be a determinant of serum mtDNA DAMP levels, and that serum levels of mtDNA DAMPs after multiple transfusions may predict the development of ARDS. Collectively, these findings support the idea that mtDNA DAMPs in transfusion products significantly contribute to the incidence of ARDS after massive transfusions. LEVEL OF EVIDENCE: Prognostic study, level II; therapeutic study, level II.

Alarmins and Clinical Outcomes After Major Abdominal Surgery-A Prospective Study.

PURPOSE: Tissue injury causing immune response is an integral part of surgical procedure. Evaluation of the degree of surgical trauma could help to improve postoperative management and determine the clinical outcomes. MATERIALS AND METHODS: We analyzed serum levels of alarmins, including S100A5, S100A6, S100A8, S100A9, S100A11, and S100A12; high-mobility group box 1; and heat-shock protein 70, after elective major abdominal surgery (n = 82). Blood samples were collected for three consecutive days after surgery. The goals were to evaluate the relationships among the serum levels of alarmins and selected surgical characteristics and to test potential of alarmins to predict the clinical outcomes. RESULTS: Significant, positive correlations were found for high-mobility group box 1 with the length of surgery, blood loss, and intraoperative fluid intake for all three days of blood sampling. The protein S100A8 serum levels showed positive correlations with intensive care unit length of stay, 28-day and in-hospital mortality. The protein S100A12 serum levels had significant, positive correlations with intensive care unit length of stay, 28-day mortality, and in-hospital mortality. We did not find significant differences in alarmin levels between cancer and noncancer subjects. CONCLUSION: The high-mobility group box 1 serum levels reflect the degree of surgical injury, whereas proteins S100A8 and S100A12 might be considered good predictors of major abdominal surgery morbidity and mortality.

Elevated Serum Level of HMGB1 in Patients with the Antiphospholipid Syndrome.

Pregnancy problems are common in patients with rheumatic disease; indeed, autoimmune disorders and autoantibodies can affect pregnancy progress and lead to maternal complications. Recent studies have highlighted a close association between HMGB1, chronic inflammation, and autoimmune diseases. Thus, in this investigation, we analyzed serum levels of HMGB1, an alarmin which plays a pivotal role in inducing and enhancing immune cell function. Sera from 30 patients with antiphospholipid syndrome (11 primary and 19 secondary APS), 35 subjects with pregnancy morbidity, and 30 healthy women were analysed for HMGB1 and its putative receptor RAGE (sRAGE) by Western blot and for TNF-α by ELISA. Results revealed that APS patients showed significantly increased serum levels of HMGB1, sRAGE, and the proinflammatory cytokine TNF-α, as compared to healthy women. However, also, the pregnancy morbidity subjects showed significantly increased levels of HMGB1 and sRAGE as well as TNF-α compared to healthy women. Our findings suggest that in subjects with pregnancy morbidity, including obstetric APS, elevated levels of HMGB1/sRAGE may represent an alarm signal, indicating an increase of proinflammatory triggers. Further studies are needed to evaluate the role of HMGB1/sRAGE as a possible tool to evaluate the risk stratification of adverse pregnancy outcomes.

In neonates S100A8/S100A9 alarmins prevent the expansion of a specific inflammatory monocyte population promoting septic shock.

The high susceptibility of newborn infants to sepsis is ascribed to an immaturity of the neonatal immune system, but the molecular mechanisms remain unclear. Newborn monocytes massively release the alarmins S100A8/S100A9. In adults, these are major regulators of immunosuppressive myeloid-derived suppressor cells (MDSCs). We investigated whether S100A8/S100A9 cause an expansion of monocytic MDSCs (Mo-MDSCs) in neonates, thereby contributing to an immunocompromised state. Mo-MDSCs have been assigned to CD14+/human leukocyte antigen (HLA)-DR-/low/CD33+ monocytes in humans and to CD11b+/Gr-1int/Ly6G-/Ly6Chi cells in mice. We found monocytes with these phenotypes significantly expanded in their respective newborns. Functionally, however, they did not prove immunosuppressive but rather responded inflammatorily to microbial stimulation. Their expansion did not correlate with high S100A8/S100A9 levels in cord blood. Murine studies revealed an excessive expansion of CD11b+/Gr-1int/Ly6G-/Ly6Chi monocytes in S100A9-/- neonates compared to wild-type neonates. This strong baseline expansion was associated with hyperinflammatory responses during endotoxemia and fatal septic courses. Treating S100A9-/- neonates directly after birth with S100A8/S100A9 alarmins prevented excessive expansion of this inflammatory monocyte population and death from septic shock. Our data suggest that a specific population of inflammatory monocytes promotes fatal courses of sepsis in neonates if its expansion is not regulated by S100A8/S100A9 alarmins.-Heinemann, A. S., Pirr, S., Fehlhaber, B., Mellinger, L., Burgmann, J., Busse, M., Ginzel, M., Friesenhagen, J., von Köckritz-Blickwede, M., Ulas, T., von Kaisenberg, C. S., Roth, J., Vogl, T., Viemann, D. In neonates S100A8/S100A9 alarmins prevent the expansion of a specific inflammatory monocyte population promoting septic shock.