Shedding of tumor necrosis factor receptors by activated human neutrophils

Regulation of plasma soluble receptors of TNF and IL-1 in patients with COVID-19 differs from that observed in sepsis

OBJECTIVES

IL-1α/β and TNF are closely linked to the pathology of severe COVID-19 and sepsis. The soluble forms of their receptors, functioning as decoy receptors, exhibit inhibitory effects. However, little is known about their regulation in severe bacterial and viral infections, which we aimed to investigate in this study.

METHODS

The circulating soluble receptors of TNF (sTNFR1 and sTNFR2) and IL-1α/β (sIL-1R1, sIL-1R2) were evaluated in the plasma of patients with COVID-19, severe bacterial infections, and sepsis and compared with healthy controls. Additionally, IL1R1, IL1R2, TNFRSF1A, and TNFRSF1B expression was evaluated at the single cell level in PBMCs derived from COVID-19 or sepsis patients.

RESULTS

Plasma concentrations of sIL-1R1, sTNFR1, and sTNFR2 were significantly higher in COVID-19 patients compared to healthy subjects. Notably, sIL-1R1 levels were particularly elevated in ICU COVID-19 patients, and transcriptome analysis indicated heightened IL1R1 expression in PBMCs from severe COVID-19 patients. In severe bacterial infections, only sTNFR1 and sTNFR2 exhibited increased levels compared to healthy controls. Sepsis patients had decreased sIL-1R1 plasma concentrations but elevated sIL-1R2, sTNFR1, and sTNFR2 levels compared to healthy individuals, reflecting the heightened expression due to the increased numbers of monocytes present in sepsis. Finally, elevated concentrations of sIL-1R2, sTNFR1, and sTNFR2 were moderately associated with reduced 28-day survival in sepsis patients.

CONCLUSION

Our study reveals distinct regulation of plasma concentrations of soluble IL-1 receptors in COVID-19 and sepsis. Moreover, soluble TNF receptors 1 and 2 consistently rise in all conditions and show a positive correlation with disease severity in sepsis.

Immune markers of severe acute pancreatitis

PURPOSE OF REVIEW

Acute pancreatitis is a common acute inflammatory disorder of the pancreas, and its incidence has been increasing worldwide. Approximately 10% of acute pancreatitis progresses to severe acute pancreatitis (SAP), which carries significant morbidity and mortality. Disordered immune response to pancreatic injury is regarded as a key event that mediates systemic injury in SAP. In this article, we review recent developments in immune biomarkers of SAP and future directions for research.

RECENT FINDINGS

Given the importance of the NLRP3-inflammasome pathway in mediating systemic inflammatory response syndrome and systemic injury, recent studies have investigated associations of SAP with systemic levels of activators of NLRP3, such as the damage associated molecular patterns (DAMPs) for the first time in human SAP. For example, circulating levels of histones, mitochondrial DNAs, and cell free DNAs have been associated with SAP. A panel of mechanistically relevant immune markers (e.g., panel of Angiopoeitin-2, hepatocyte growth factor, interleukin-8 (IL-8), resistin and sTNF-α R1) carried higher predictive accuracies than existing clinical scores and individual immune markers. Of the cytokines with established relevance to SAP pathogenesis, phase 2 trials of immunotherapies, including tumor necrosis factor (TNF)-alpha inhibition and stimulation of IL-10 production, are underway to determine if altering the immunologic response can reduce the severity of acute pancreatitis (AP).

SUMMARY

Circulating systemic levels of various DAMPs and a panel of immune markers that possibly reflect activities of different pathways that drive SAP appear promising as predictive biomarkers for SAP. But larger multicenter studies are needed for external validation. Studies investigating immune cellular pathways driving SAP using immunophenotyping techniques are scarce. Interdisciplinary efforts are also needed to bring some of the promising biomarkers to the bedside for validation and testing for clinical utility. Studies investigating the role of and characterization of altered gut-lymph and gut-microbiota in severe AP are needed.

The rs11684747 and rs55790676 SNPs of ADAM17 influence tuberculosis susceptibility and plasma levels of TNF, TNFR1, and TNFR2

Introduction

The proteolytic activity of A Disintegrin and Metalloproteinase 17 (ADAM17) regulates the release of tumor necrosis factor (TNF) and TNF receptors (TNFRs) from cell surfaces. These molecules play important roles in tuberculosis (TB) shaping innate immune reactions and granuloma formation.

Methods

Here, we investigated whether single nucleotide polymorphisms (SNPs) of ADAM17 influence TNF and TNFRs levels in 224 patients with active TB (ATB) and 118 healthy close contacts. Also, we looked for significant associations between SNPs of ADAM17 and ATB status. TNF, TNFR1, and TNFR2 levels were measured in plasma samples by ELISA. Four SNPs of ADAM17 (rs12692386, rs1524668, rs11684747, and rs55790676) were analyzed in DNA isolated from peripheral blood leucocytes. The association between ATB status, genotype, and cytokines was analyzed by multiple regression models.

Results

Our results showed a higher frequency of rs11684747 and rs55790676 in close contacts than ATB patients. Coincidentally, heterozygous to these SNPs of ADAM17 showed higher plasma levels of TNF compared to homozygous to their respective ancestral alleles. Strikingly, the levels of TNF and TNFRs distinguished participant groups, with ATB patients displaying lower TNF and higher TNFR1/TNFR2 levels compared to their close contacts.

Conclusion

These findings suggest a role for SNPs of ADAM17 in genetic susceptibility to ATB.

Bioavailability of the tumor necrosis factor alpha/regulated on activation, normal T cell expressed and secreted (RANTES) biosystem inside the gestational sac during the pre-immune stages of embryo development

OBJECTIVES

In-vivo studies of the bioavailability of major components of the tumor necrosis factor alpha (TNFα) biosystem inside the gestational sac during embryogenesis have not been reported. We sought to determine the concentration of TNFα, soluble (s) TNFα receptors (sTNFR1, sTNFR2), and RANTES in the primate extraembryonic celomic fluid (ECF).

METHODS

A validated timed-pregnant baboon animal model (N: 10) for experimental research in pregnancy was used to collect paired maternal blood and ECF samples in ongoing pregnancies. The concentrations (pg/dL) of TNFα, sTNFR1, sTNFR2, and RANTES were then determined by ELISA immunoassays.

RESULTS

All animals delivered at term healthy newborns. The differential concentration of TNFα, sTNFR1, sTNFR2, and RANTES between the maternal plasma and the ECF could be determined with ratios for TNFα (5.4), sTNFR2 (1.85) and RANTES (3.59) that contrasted with that of sTNFR1 (0.07), which favored the gestational sac compartment. No significant correlations were noted between maternal plasma and ECF TNFR1, sTNFR2 and RANTES. There was a trend for a correlation between TNFα in maternal plasma and ECF (R=0.74; p=0.07).

CONCLUSIONS

We report the physiological concentrations of TNFα, sTNFR1, sTNFR2, and RANTES in extraembryonic celomic fluid during embryogenesis in primates.

Myeloperoxidase Inhibition Reverses Biomarker Profiles Associated With Clinical Outcomes in HFpEF

BACKGROUND

Systemic microvascular dysfunction and inflammation are postulated to play a pathophysiologic role in heart failure with preserved ejection fraction (HFpEF).

OBJECTIVES

This study aimed to identify biomarker profiles associated with clinical outcomes in HFpEF and investigate how inhibition of the neutrophil-derived reactive oxygen species-producing enzyme, myeloperoxidase, affects these biomarkers.

METHODS

Using supervised principal component analyses, the investigators assessed the associations between baseline plasma proteomic Olink biomarkers and clinical outcomes in 3 independent observational HFpEF cohorts (n = 86, n = 216, and n = 242). These profiles were then compared with the biomarker profiles discriminating patients treated with active drug vs placebo in SATELLITE (Safety and Tolerability Study of AZD4831 in Patients With Heart Failure), a double-blind randomized 3-month trial evaluating safety and tolerability of the myeloperoxidase inhibitor AZD4831 in HFpEF (n = 41). Pathophysiological pathways were inferred from the biomarker profiles by interrogation of the Ingenuity Knowledge database.

RESULTS

TNF-R1, TRAIL-R2, GDF15, U-PAR, and ADM were the top individual biomarkers associated with heart failure hospitalization or death, and FABP4, HGF, RARRES2, CSTB, and FGF23 were associated with lower functional capacity and poorer quality of life. AZD4831 downregulated many markers (most significantly CDCP1, PRELP, CX3CL1, LIFR, VSIG2). There was remarkable consistency among pathways associated with clinical outcomes in the observational HFpEF cohorts, the top canonical pathways being associated with tumor microenvironments, wound healing signaling, and cardiac hypertrophy signaling. These pathways were predicted to be downregulated in AZD4831 relative to placebo-treated patients.

CONCLUSIONS

Biomarker pathways that were most strongly associated with clinical outcomes were also the ones reduced by AZD4831. These results support the further investigation of myeloperoxidase inhibition in HFpEF.

Molecular Basic of Pharmacotherapy of Cytokine Imbalance as a Component of Intervertebral Disc Degeneration Treatment

Intervertebral disc degeneration (IDD) and associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. With age, IDD progresses, leading to spondylosis, spondylarthrosis, herniated disc, spinal canal stenosis. One of the leading mechanisms in the development of IDD and chronic back pain is an imbalance between pro-inflammatory and anti-inflammatory cytokines. However, classical therapeutic strategies for correcting cytokine imbalance in IDD do not give the expected response in more than half of the cases. The purpose of this review is to update knowledge about new and promising therapeutic strategies based on the correction of the molecular mechanisms of cytokine imbalance in patients with IDD. This review demonstrates that knowledge of the molecular mechanisms of the imbalance between pro-inflammatory and anti-inflammatory cytokines may be a new key to finding more effective drugs for the treatment of IDD in the setting of acute and chronic inflammation.

Severe acute pancreatitis exhibits distinct cytokine signatures and trajectories in humans: a prospective observational study

Severe acute pancreatitis (SAP) is associated with substantial morbidity and mortality. Several cytokines have been identified to have pathophysiological significance in SAP, but studies characterizing their early trajectories are lacking. Here we characterize the early trajectories of seven key cytokines associated with SAP and compare them with non-SAP subjects. Five proinflammatory cytokines (angiopoietin-2, interleukin-6, interleukin-8, monocyte chemoattractant protein-1, resistin) and two anti-inflammatory cytokines (hepatocyte growth factor, and soluble tumor necrosis factor-α receptor-1A) were measured in a prospective cohort of acute pancreatitis subjects (2012-2016) at the time of enrollment and then every 24 h for 5 days or until discharge. The cytokines' levels and trajectories were calibrated based on date of pain onset and were compared between healthy controls and three severity categories (mild, moderate, and severe). The cohort (n = 170) consisted of 27 healthy controls, 65 mild, 38 moderate, and 40 SAP. From day 1 of symptom onset, SAP subjects exhibited significantly higher levels of both pro- and anti-inflammatory cytokines compared with non-SAP and healthy subjects. But in SAP subjects, all proinflammatory cytokines' levels trended downward after day 2 (except for a flat slope for angiopoeitin-2) whereas for non-SAP subjects, the trajectory was upward: this trajectory difference between SAP versus non-SAP subjects resulted in narrowing of the differences initially seen on day 1 for proinflammatory cytokines. For anti-inflammatory cytokines, the trajectories were uniformly upward for both SAP and non-SAP subjects. Proinflammatory cytokine response is an early and time-sensitive event in SAP that should be accounted for when designing future biomarker studies and/or therapeutic trials.NEW & NOTEWORTHY In this study, we showed that the proinflammatory cytokine response in SAP is an early event, with subsequent downregulation of proinflammatory cytokines beginning at day 1 of symptom onset. Our findings underscore the importance of enrolling subjects very early in the disease course when conducting studies to investigate early immune events of SAP; this current study also serves as an important reference for the design of future biomarker studies and therapeutic trials in SAP.

High Levels of TNF-α and TIM-3 as a Biomarker of Immune Reconstitution Inflammatory Syndrome in People with HIV Infection

Immune reconstitution inflammatory syndrome (IRIS) is an exacerbated immune response that can occur to HIV+ patients after initiating antiretroviral therapy (ART). IRIS pathogenesis is unclear, but dysfunctional and exhausted cells have been reported in IRIS patients, and the TIM-3/Gal-9 axis has been associated with chronic phases of viral infection. This study aimed to evaluate the soluble levels of TIM-3 and Gal-9 and their relationship with IRIS development. TIM-3, Gal-9, TNF-α, IFN-γ, IL-6, TNFR1, TNFR2, E-cadherin, ADAM10, and ADAM17 were measured to search for IRIS-associated biomarkers in plasma samples from 0-, 4-, 8-, 12-, and 24-weeks after ART initiation of 61 HIV+ patients (15 patients developed IRIS, and 46 did not). We found that patients who developed IRIS had higher levels of TIM-3 [median 4806, IQR: 3206-6182] at the time of the IRIS events, compared to any other follow-up time evaluated in these patients or compared with a control group of patients who did not develop IRIS. Similarly, IRIS patients had a higher TNF-α level [median 10.89, IQR: 8.36-12.34] at IRIS events than any other follow-up time evaluated. Other molecules related to the TIM-3 and TNF-α pathway (Gal-9, IL-6, IFN-γ, TNFR1, TNFR2, ADAM-10, and ADAM-17) did not change during the IRIS events. In conclusion, our data suggest that a high level of soluble TIM-3 and TNF-α could be used as an IRIS biomarker.

Biological Drugs in Guillain-Barré Syndrome: An Update

Background:

Guillain-Barré Syndrome (GBS) is currently considered the most common global cause of acute flaccid paralysis. Currently, standard therapy for Guillain-Barré Syndrome includes intravenous immunoglobulin or plasma exchange. Despite medical advances regarding these treatments, many treated patients do not reach full recovery. Therefore several biological agents have attracted the attentions from researchers during the last decades, and various studies have investigated their role in Guillain-Barré Syndrome.

Objective:

The present study aims to address emerging biological approaches to GBS while considering their efficiency and safety in treating the disease.

Materials and Methods:

An extensive electronic literature search was conducted by two researchers from April 2016 to July 2016. Original articles, clinical trials, systematic reviews (with or without meta-analysis) and case reports were selected. Titles and abstracts of papers were screened by reviewers to determine whether they met the eligibility criteria, and full texts of the selected articles were retrieved.

Results:

Herein authors focused on the literature data concerning emerging biological therapeutic agents, namely anti-C5 monoclonal antibody (Eculizumab), anti-C1q monoclonal antibody, anti-T cell monoclonal antibody, anti-CD2 monoclonal antibody, anti L-selectin monoclonal antibody, anti-CD20 monoclonal antibody (Rituximab), anti-CD52 monoclonal antibody (Alemtuzumab) and cytokine targets. By far, none of these agents have been approved for the treatment of GBS by FDA.

Conclusion:

Literature findings represented in current review herald promising results for using these biological targets. Current review represents a summary of what is already in regards and what progress is required to improve the immunotherapeutic approach of treating GBS via future studies.

Phospholipase A2 Inhibitor from Crotalus durissus terrificus rattlesnake: Effects on human peripheral blood mononuclear cells and human neutrophils cells

Crotalus Neutralizing Factor (CNF) is an inhibitor of phospholipase A₂ (PLA₂), present in the blood plasma of Crotalus durissus terrificus snake. This inhibitor neutralizes the lethal and enzymatic activity of crotoxin, the main neurotoxin from this venom. In this study, we investigated the effects of CNF on the functionality of human peripheral blood mononuclear cells (PBMCs) and human neutrophils. The following parameters were evaluated: viability and proliferation, chemotaxis, cytokines and LTB₄ production, cytosolic PLA₂s activity, myeloperoxidase (MPO) and superoxide anion (O₂^-) production. CNF showed no toxicity on PBMCs or neutrophils, and acts by stimulating the release of TNF-α and LTB₄, but neither stimulates IL-10 and IL-2 nor affects PBMCs proliferation and O₂^- release. In neutrophils, CNF induces chemotaxis but does not induce the release of both MPO and O₂^-. However, it induces LTB₄ and IL-8 production. These data show the influence of CNF on PBMCs' function by inducing TNF-α and LTB₄ production, and on neutrophils, by stimulating chemotaxis and LTB₄ production, via cytosolic PLA₂ activity, and IL-8 release. The inflammatory profile produced by CNF is shown for the first time. Our present results suggest that CNF has a role in activation of leukocytes and exert proinflammatory effects on these cell.

The Clinical Significance of Increased Serum Proinflammatory Cytokines, C-Reactive Protein, and Erythrocyte Sedimentation Rate in Patients with Hidradenitis Suppurativa

Objectives

To assess inflammatory serum markers including serum proinflammatory cytokines, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) according to the clinical inflammatory activity of patients with hidradenitis suppurativa (HS).

Patients and Methods

Seventy-four patients with HS were studied based on the Hidradenitis Suppurativa-Physician Global Assessment (HS-PGA) score and Hurley staging system. Proinflammatory cytokines were measured using a multiplex cytokine assay. Twenty-two healthy volunteers were recruited.

Results

Serum interleukin- (IL-) 6, IL-23, soluble tumour necrosis factor alpha (TNF-α) receptor I (sTNF-RI), CRP, and ESR were different in the patients with HS compared with those in the healthy controls (P < 0.05). The levels of IL-1β, IL-6, IL-8, IL-10, IL-12p70, IL-17A, sTNF-RII, CRP, and ESR were significantly elevated according to inflammatory activity based on HS-PGA scores (r > 0.25, P < 0.05). The levels of IL-6 (r = 0.53, P < 0.001), CRP (r = 0.54, P < 0.001), and ESR (r = 0.60, P < 0.001) were especially well correlated with clinical inflammatory activity based on HS-PGA scores. The levels of IL-6, IL-8, sTNF-RI, sTNF-RII, CRP, and ESR were significantly elevated according to Hurley staging system.

Conclusions

Serum proinflammatory cytokines, CRP, and ESR are increased in relation to the clinical inflammatory activity of patients with HS compared with healthy controls. Serum IL-6, CRP, and ESR are effective biomarkers for evaluating the severity of HS.

Persistent p55TNFR expression impairs T cell responses during chronic tuberculosis and promotes reactivation

The pleiotropic activities of TNF are mediated by two structurally related but functionally distinct type I transmembrane receptors, p55TNFR and p75TNFR expressed in most cell types, that can be cleaved and act as TNF scavengers. Here, we investigated the effect of persistent p55TNFR cell surface expression during aerosol inhalation challenge with virulent M. tuberculosis H37Rv. We demonstrated that persistency of p55TNFR in macrophage cultures increased the synthesis of soluble TNF, p75TNFR and NO, however, had no effects on bacteria killing ability. Furthermore, it did not facilitate enhanced protection to primary acute M. tuberculosis infection in p55^∆NS mice. Without exacerbated lung inflammation, we found a compensatory increase in p75TNFR shedding and decrease in bioactive TNF in BAL of p55^∆NS mice after M. tuberculosis challenge. Defective expressions of CD44 and INFγ attributed to an impaired T cell response during persistent p55TNFR expression that caused marginal transient susceptibility during chronic infection. Moreover, persistent p55TNFR expression induced early reactivation during latent tuberculosis infection. These data indicate a prominent role of p55TNFR shedding in Th1 mediated protection against chronic and latent tuberculosis infection.

Alterations in membrane-associated CD14 expression and the simultaneous liberation of soluble CD14 fragment in adherent macrophages mediated by a leukocyte carboxyl/aspartate protease

Investigations sought to discover the biochemical mechanisms in macrophages that mediate the `shedding' of soluble CD14 fragment. Stimulated macrophages display both increased liberation of soluble CD14 fragment and decreases in residual membrane-associated CD14 complexes following exposure to activating agents ( fMLP/A23187). Application of `class-specific' protease inhibitors revealed that a thiol/cysteine was involved in the biochemical production of soluble CD14 fractions and that a metalloprotease enzymatically degraded soluble CD14 fragment. Exposure of macrophages to individual proteases revealed that both cathepsin-D and elastase promoted variable depletion of membrane-associated CD14 complexes. Additionally, cathepsin-D, and to a lesser extent elastase, generated soluble CD14 fragment. Related studies isolated a carboxyl/aspartate protease from activated macrophages using pepstatin-A affinity chromatography. The physical and functional properties of macrophage pepstatin-A binding protein fractions closely corresponded with the known characteristics of cathepsin-D with respect to: (i) cellular origin; (ii) binding-avidity of carboxyl/aspartate proteases for pepstatin-A; (iii) non-specific proteolysis of haemoglobin detected by Hb-PAGE zymography; and (iv) hydrolysis of a synthetic cathepsin-D-specific peptide substrate. Interpretation of these findings collectively implies that activated leukocytes can biochemically alter membrane-associated CD14 complex expression and promote the liberation of soluble CD14 fragment in both activated and non-activated cell populations.

Mass spectrometry-based proteomics revealed Glypican-1 as a novel ADAM17 substrate

ADAM17 (a disintegrin and metalloproteinase 17) is a plasma membrane metalloprotease involved in proteolytic release of the extracellular domain of many cell surface molecules, a process known as ectodomain shedding. Through this process, ADAM17 is implicated in several aspects of tumor growth and metastasis in a broad range of tumors, including head and neck squamous cell carcinomas (HNSCC). In this study, mass spectrometry-based proteomics approaches revealed glypican-1 (GPC1) as a new substrate for ADAM17, and its shedding was confirmed to be metalloprotease-dependent, induced by a pleiotropic agent (PMA) and physiologic ligand (EGF), and inhibited by marimastat. In addition, immunoblotting analysis of GPC1 in the extracellular media from control and ADAM17shRNA pointed to a direct involvement of ADAM17 in the cleavage of GPC1. Moreover, mass spectrometry-based interactome analysis of GPC1 revealed biological functions and pathways related mainly to cellular movement, adhesion and proliferation, which were events also modulated by up regulation of full length and cleavage GPC1. Altogether, we showed that GPC1 is a novel ADAM17 substrate, thus the function of GPC1 may be modulated by proteolysis signaling.

BIOLOGICAL SIGNIFICANCE

Inhibition of metalloproteases as a therapeutic approach has failed because there is limited knowledge of the degradome of individual proteases as well as the cellular function of cleaved substrates. Using different proteomic techniques, this study uncovered novel substrates that can be modulated by ADAM17 in oral squamous cell carcinoma cell line. Glypican-1 was validated as a novel substrate for ADAM17, with important function in adhesion, proliferation and migration of carcinoma cells. Therefore, this study opens new avenues regarding the proteolysis-mediated function of GPC1 by ADAM17.

Cytokines and chemokines: At the crossroads of cell signalling and inflammatory disease

Inflammation occurs as a result of exposure of tissues and organs to harmful stimuli such as microbial pathogens, irritants, or toxic cellular components. The primary physical manifestations of inflammation are redness, swelling, heat, pain, and loss of function to the affected area. These processes involve the major cells of the immune system, including monocytes, macrophages, neutrophils, basophils, dendritic cells, mast cells, T-cells, and B-cells. However, examination of a range of inflammatory lesions demonstrates the presence of specific leukocytes in any given lesion. That is, the inflammatory process is regulated in such a way as to ensure that the appropriate leukocytes are recruited. These events are in turn controlled by a host of extracellular molecular regulators, including members of the cytokine and chemokine families that mediate both immune cell recruitment and complex intracellular signalling control mechanisms that characterise inflammation. This review will focus on the role of the main cytokines, chemokines, and their receptors in the pathophysiology of auto-inflammatory disorders, pro-inflammatory disorders, and neurological disorders involving inflammation.

Levels of soluble TNF-RII are increased in serum of patients with primary progressive multiple sclerosis

The levels of soluble tumor necrosis factor receptor II (sTNF-RII) were determined in serum of 161 untreated multiple sclerosis (MS) patients with different clinical forms and 46 healthy controls (HC) by ELISA. Our results show that serum sTNF-RII levels were significantly increased in patients with primary progressive MS (PPMS) compared with other MS forms and HC. Although sTNF-RII levels significantly increased over a 2-year follow-up period in a subgroup of PPMS patients, they could not discriminate between patients with and without disability progression. Additional studies are needed to further implicate sTNF-RII in patients with PPMS.

Attenuated thermoregulatory, metabolic, and liver acute phase protein response to heat stroke in TNF receptor knockout mice

Tumor necrosis factor (TNF) is considered an adverse mediator of heat stroke (HS) based on clinical studies showing high serum levels. However, soluble TNF receptors (sTNFR; TNF antagonists) were higher in survivors than nonsurvivors, and TNFR knockout (KO) mice showed a trend toward increased mortality, suggesting TNF has protective actions for recovery. We delineated TNF actions in HS by comparing thermoregulatory, metabolic, and inflammatory responses between B6129F2 (wild type, WT) and TNFR KO mice. Before heat exposure, TNFR KO mice showed ∼0.4°C lower core temperature (Tc; radiotelemetry), ∼10% lower metabolic rate (Mr; indirect calorimetry), and reduced plasma interleukin (IL)-1α and sIL-1RI than WT mice. KO mice selected warmer temperatures than WT mice in a gradient but remained hypothermic. In the calorimeter, both genotypes showed a similar heating rate, but TNFR KO maintained lower Tc and Mr than WT mice for a given heat exposure duration and required ∼30 min longer to reach maximum Tc (42.4°C). Plasma IL-6 increased at ∼3 h of recovery in both genotypes, but KO mice showed a more robust sIL-6R response. Higher sIL-6R in the KO mice was associated with delayed liver p-STAT3 protein expression and attenuated serum amyloid A3 (SAA3) gene expression, suggesting the acute phase response (APR) was attenuated in these mice. Our data suggest that the absence of TNF signaling induced a regulated hypothermic state in the KO mice, TNF-IL-1 interactions may modulate Tc and Mr during homeostatic conditions, and TNF modulates the APR during HS recovery through interactions with the liver IL-6-STAT3 pathway of SAA3 regulation.

Differential effects of the autophagy inhibitors 3-methyladenine and chloroquine on spontaneous and TNF-α-induced neutrophil apoptosis

Autophagy and apoptosis cooperate to modulate cell survival. Neutrophils are short-lived cells and apoptosis is considered to be the major mechanism of their death. In the present study, we addressed whether autophagy regulates neutrophil apoptosis and investigated the effects of autophagy inhibition on apoptosis of human neutrophils. We first showed that the established autophagy inhibitors 3-methyladenine (MA) and chloroquine (CQ) markedly accelerated spontaneous neutrophil apoptosis as was evidenced by phosphatidylserine exposure, DNA fragmentation and caspase-3 activation. Apoptosis induced by the autophagy inhibitors was completely abrogated by a pan-caspase inhibitor Q-VD-OPh. Unexpectedly, both MA and CQ significantly delayed neutrophil apoptosis induced by TNF-α, although the inhibitors did attenuate late pro-survival effect of the cytokine. The effect was specific for TNF-α because it was not observed in the presence of other inflammation-associated cytokines (IL-1β or IL-8). The autophagy inhibitors did not modulate surface expression of TNF-α receptors in the absence or presence of TNF-α. Both MA and CQ induced a marked down-regulation of a key anti-apoptotic protein Mcl-1 but did not affect significantly the levels of another anti-apoptotic protein Bcl-X(L). Finally, to confirm the effects of the pharmacological inhibition of autophagy by a genetic approach, we evaluated the consequences of siRNA-mediated autophagy suppression in neutrophil-like differentiated HL60 cells. Knockdown of ATG5 in the cells resulted in accelerated spontaneous apoptosis but attenuated TNF-α-induced apoptosis. Together, these data suggest that autophagy regulates neutrophil apoptosis in an inflammatory context-dependent manner and mediates the early pro-apoptotic effect of TNF-α in neutrophils.

Baseline TNFα operational capacity in fetal and maternal circulation prior to the onset of labor: "tuned for different purposes"

OBJECTIVE

In this study, we sought to characterize the tumor necrosis factor α (TNFα) baseline operational capacity in mature fetuses and their mothers prior to the onset of labor.

MATERIALS AND METHODS

We used an experimental pregnant nonhuman primate model to measure the plasma concentration of TNFα, TNF transmembrane receptor I (TNFRI), and TNFRII with validated enzyme-linked immunosorbent assays. Coefficients of correlations between the maternal and the fetal values and the soluble TNFα, TNFRI, or TNFRII concentrations and ratios were calculated.

RESULTS

The TNFα/TNFRI ratio was 3 times lower in fetal circulation than in maternal circulation. No correlations were noted between the maternal and the fetal TNFα, TNFRI, or TNFRII plasma concentrations.

CONCLUSIONS

These findings suggest that the fetal and maternal baseline circulatory operational capacities of TNFα are independent of each other and tuned differently. This differential regulation of TNFα in fetal and maternal circulation at the end of pregnancy may be guided to protect the fetus from the systemic inflammatory response that is essential for the mechanisms of labor to proceed in the mother.

Tumor necrosis factor receptors: biology and therapeutic potential in kidney diseases

The major evolutionary advance represented in the human immune system is a mechanism of antigen-directed immunity in which tumor necrosis factor (TNF)-α and TNF receptors (TNFRs) play essential roles. Binding of TNF-α to the 55-kDa type I TNFR (TNFR1, TNFRSF1A, CD120a, p55) or the 75-kDa type II TNFR (TNFR2, TNFRSF1B, CD120b, p75) activates signaling pathways controlling inflammatory, immune and stress responses, as well as host defense and apoptosis. Multiple studies have investigated the role of TNFRs in the development of early and late renal failure (diabetic nephropathy, nephroangiosclerosis, acute kidney transplant rejection, renal cell carcinoma, glomerulonephritis, sepsis and obstructive renal injury). This article reviews the general characteristics, the analytical aspects and the biology of TNFRs in this domain. In addition, the potential therapeutic application of specific TNFR blockers is discussed.

The effect of tumour necrosis factor-alpha (TNF-alpha) muteins on human neutrophils in vitro

Tumour necrosis factor-α (TNF-α) has been implicated as an important inflammatory mediator. In vitro, TNF-α is reported to activate human polymorphonuclear neutrophils (PMN), inducing responses such as phagocytic activity, degranulation and oxidative metabolism. Biological responses to TNF-α are initiated by its binding to specific cell surface receptors, and various studies have shown that the major TNF receptor species on PMN is the 75 kDa receptor. To verify the suggestion that the receptor binding domain includes the region close to the N-terminus of the TNF-α molecule, four TNF-α derivatives termed muteins were constructed, using a synthetic cDNA fragment substituting the N-terminal 3–7 selected hydrophilic or hydrophobic amino acids in the original TNF-α genomic DNA. Binding of muteins to PMN was assessed using monoclonal antibodies recognizing either the 55 kDa (p55) or the 75 kDa (p75) TNF receptor subtypes. Blocking by muteins of anti-p75 antibody binding to PMN was as expected from their N-terminal amino acid composition and hydrophilic properties. Hydrophilic muteins competed well with anti-TNF receptor antibodies for binding to the p75 receptor. In contrast, hydrophobic muteins were unable to block anti-p75 binding. Similarly, degranulation, chemiluminescence or enhancement of the PMN response to specific stimuli by the muteins correlated with the hydrophilic properties of the muteins. The significance of these observations in relation to the molecular structure of TNF-α is discussed.

Contribution of TNF receptor 1 to retinal neural cell death induced by elevated glucose

Diabetic retinopathy (DR), a leading cause of vision loss and blindness among working-age adults, holds several hallmarks of an inflammatory disease. The increase in cell death in neural retina is an early event in the diabetic retina, preceding the loss of microvascular cells. Since tumor necrosis factor-α (TNF-α) has been shown to trigger the death of perycites and endothelial cells as well as the breakdown of the blood-retinal barrier, we set out to investigate whether TNF-α acting through tumor necrosis factor receptor 1 (TNFR1), the major receptor responsible for mediating TNF-induced cell death, could also be responsible for the early neuronal cell death observed in DR. We used retinal neural cell cultures exposed to high glucose conditions, to mimic hyperglycaemia, and evaluated the contribution of TNFR1 in neural cell death. TNFR1 was found to be present to a great extent in retinal neurons and the levels of this receptor were found to be altered in cells cultured in high glucose conditions. High glucose induced an early decrease in cell viability, an increase in apoptosis and a higher immunoreactivity for the cleaved caspase-3, indicating a high glucose-induced caspase-dependent cell death. These observations were correlated with an increase in TNF-α expression. Nonetheless, inhibiting the activation of TNFR1 was sufficient to prevent the decrease in cell viability and the increase in retinal cell death by apoptosis. In conclusion, our data indicate that TNF-α acting through TNFR1 is responsible for the high glucose-induced cell death and that blocking the activity of this receptor is an adequate strategy to avoid cell loss in such conditions.

Tumour necrosis factor receptor trafficking dysfunction opens the TRAPS door to pro-inflammatory cytokine secretion

Cytokines are secreted from macrophages and other cells of the immune system in response to pathogens. Additionally, in autoinflammatory diseases cytokine secretion occurs in the absence of pathogenic stimuli. In the case of TRAPS [TNFR (tumour necrosis factor receptor)-associated periodic syndrome], inflammatory episodes result from mutations in the TNFRSF1A gene that encodes TNFR1. This work remains controversial, however, with at least three distinct separate mechanisms of receptor dysfunction having been proposed. Central to these hypotheses are the NF-κB (nuclear factor κB) and MAPK (mitogen-activated protein kinase) families of transcriptional activators that are able to up-regulate expression of a number of genes, including pro-inflammatory cytokines. The present review examines each proposed mechanism of TNFR1 dysfunction, and addresses how these processes might ultimately impact upon cytokine secretion and disease pathophysiology.

Bacterial translocation in HIV-infected patients with HCV cirrhosis: implication in hemodynamic alterations and mortality

OBJECTIVE

Analysis of the influence of portal hypertension on intestinal permeability in HIV-infected patients with hepatitis C virus (HCV)-related cirrhosis and of the prognostic significance of consequent macrophage activation.

METHODS

Twenty HIV-monoinfected patients, 70 patients with HIV-HCV coinfection, 20 of them with compensated and 50 with decompensated cirrhosis, and 20 healthy controls were evaluated for intestinal permeability [measured by lipopolysaccharide-binding protein (LBP) serum levels], macrophage activation [soluble CD14, soluble tumour necrosis factor receptor 55 Kd, and interleukin 6 (IL-6)], and activation of the rennin-angiotensin-aldosterone axis. Patients with decompensated cirrhosis were monitored for a median period of 429 days to analyze the prognostic factors implicated in survival.

RESULTS

Patients with decompensated cirrhosis show increased LBP levels compared with HIV-monoinfected patients. Patients with increased LBP concentration showed elevated soluble CD14, soluble tumour necrosis factor receptor 55 Kd, and IL-6 levels. Twenty-two patients died, from liver-related causes, during the follow-up, and 2 more underwent liver transplantation. Child-Pugh index, CD4 T-cell count, plasma aldosterone and serum IL-6 concentrations independently predicted liver-related mortality.

CONCLUSIONS

Increased intestinal permeability, as measured by serum LBP levels, observed in patients with HIV infection is significantly higher in patients with decompensated liver cirrhosis. Proinflammatory cytokines (IL-6) are prognostic markers of HIV-HCV-coinfected patients with decompensated cirrhosis.

Haemodynamic derangement in human immunodeficiency virus-infected patients with hepatitis C virus-related cirrhosis: the role of bacterial translocation

BACKGROUND AND AIMS

Analysis of the influence of the effects of increased intestinal permeability on haemodynamic alterations in human immunodeficiency virus (HIV)-infected patients with decompensated hepatitis C virus (HCV)-related liver disease.

METHODS

Forty HIV/HCV co-infected patients and 40 HCV mono-infected patients, 20 of them with compensated cirrhosis and 20 with a previous decompensation, and 20 healthy controls, were studied. Intestinal permeability was determined by serum levels of lipopolysaccharide-binding protein (LBP). Monocyte expression of toll-like receptor 4 (TLR-4), serum levels of interleukin (IL)-6 and soluble receptors of tumour necrosis factor (sTNFRI) were analysed. Cardiac index, systemic vascular resistance (SVR), plasma renin activity (PRA) and aldosterone concentration were also determined in cirrhotic patients.

RESULTS

Serum levels of LBP, TLR-4, IL-6 and sTNFRI were significantly higher in HIV-HCV co-infected and HCV mono-infected patients with decompensated cirrhosis compared with those with compensated liver disease. Significantly lower values of SVR and higher values of cardiac index, PRA and aldosterone concentration were observed in patients with decompensated cirrhosis compared with those with compensated liver disease, particularly in those with elevated levels of IL-6. There were no significant differences between HIV/HCV co-infected and HCV mono-infected patients.

CONCLUSIONS

Higher intestinal permeability and consequent macrophage activation is observed in patients with cirrhosis; this permeability is even higher in those with portal hypertension. Serum values of IL-6 are associated with the characteristic haemodynamic derangement observed in advanced phases of cirrhosis. HIV/HCV co-infected cirrhotic patients present inflammatory and systemic haemodynamic alterations similar to those observed in HCV mono-infected patients.

Characterization of TNF receptor subtype expression and signaling on pulmonary endothelial cells in mice

TNF plays a crucial role in the pathogenesis of acute lung injury. However, the expression profile of its two receptors, p55 and p75, on pulmonary endothelium and their influence on TNF signaling during lung microvascular inflammation remain uncertain. Using flow cytometry, we characterized the expression profile of TNF receptors on the surface of freshly harvested pulmonary endothelial cells (PECs) from mice and found expression of both receptors with dominance of p55. To investigate the impact of stimulating individual TNF receptors, we treated wild-type and TNF receptor knockout mice with intravenous TNF and determined surface expression of adhesion molecules (E-selectin, VCAM-1, ICAM-1) on PECs by flow cytometry. TNF-induced upregulation of all adhesion molecules was substantially attenuated by absence of p55, whereas lack of p75 had a similar but smaller effect that varied between adhesion molecules. Selective blockade of individual TNF receptors by specific antibodies in wild-type primary PEC culture confirmed that the in vivo findings were due to direct effects of TNF receptor inhibition on endothelium and not other cells (e.g., circulating leukocytes). Finally, we found that PEC surface expression of p55 dramatically decreased in the early stages of endotoxemia following intravenous LPS, while no change in p75 expression was detected. These data demonstrate a crucial in vivo role of p55 and an auxiliary role of p75 in TNF-mediated adhesion molecule upregulation on PECs. It is possible that the importance of the individual receptors varies at different stages of pulmonary microvascular inflammation following changes in their relative expression.

TNFR2 expression on non-bone marrow-derived cells is crucial for lipopolysaccharide-induced septic shock and downregulation of soluble TNFR2 level in serum

Persistently high serum levels of soluble tumor-necrosis factor (TNF) receptor 2 (sTNFR2) have been observed in septic shock and many inflammatory diseases. However, its origin and regulation during these pathological processes are still largely unknown. In this study, murine bone marrow (BM) chimeras selectively expressing TNFR2 on either BM-derived or non-BM-derived cells were generated and challenged with lipopolysaccharide (LPS). The results show that TNFR2 expression on non-BM-derived cells is crucial for both the sensitivity of mice to LPS and the downregulation of sTNFR2 in serum. Most importantly, sTNFR2 was released from both BM- and non-BM-derived cells. Non-BM TNFR1 expression influenced the sensitivity of mice to LPS challenge but not the level of serum sTNFR2. These results provide the first in vivo evidence for the origin and regulation of sTNFR2 in serum and could aid in the development of novel anti-TNF strategies against septic shock.

Relationship Between Neonatal Blood Protein Concentrations and Placenta Histologic Characteristics in Extremely Low GA Newborns

Amniotic fluid infection with chorioamnionitis is associated with increased risks of morbidity and mortality in children born prematurely. These risks depend on the presence of a fetal inflammatory response. We measured the concentrations of 25 proteins in the blood of 871 infants born before the 28th wk of gestation and examined their placentas for acute inflammation. Newborns who had inflammatory lesions of the placenta were much more likely than their peers (p < 0.01) to have elevated blood concentrations of cytokines (IL-1β, IL-6, and TNF-α), chemokines (IL-8, MIP-1β, RANTES, and I-TAC), adhesion molecules (ICAM-1, ICAM-3, and E-selectin), matrix metalloproteinases (MMP-1 and MMP-9), the angiogenic inflammatory factor VEGF and its receptor VEGF-R2, and acute phase proteins (SAA and CRP) during the first 3 d after birth. In contrast, newborns with poor placental perfusion had lower levels of inflammatory proteins (p < 0.01; IL-6, RANTES, ICAM-1, ICAM-3, VCAM-1, E-selectin, MMP-1, MMP-9, MPO, and VEGF). An inverse pattern was found between newborn levels of VEGF and its competitive inhibitor VEGF-R1 in both the inflamed and poorly perfused placenta categories. These results confirm the predictive value of placental histology for the presence or absence of elevated inflammatory response in newborns.

Molecular and cellular mechanisms of ectodomain shedding

The extracellular domain of several membrane-anchored proteins is released from the cell surface as soluble proteins through a regulated proteolytic mechanism called ectodomain shedding. Cells use ectodomain shedding to actively regulate the expression and function of surface molecules, and modulate a wide variety of cellular and physiological processes. Ectodomain shedding rapidly converts membrane-associated proteins into soluble effectors and, at the same time, rapidly reduces the level of cell surface expression. For some proteins, ectodomain shedding is also a prerequisite for intramembrane proteolysis, which liberates the cytoplasmic domain of the affected molecule and associated signaling factors to regulate transcription. Ectodomain shedding is a process that is highly regulated by specific agonists, antagonists, and intracellular signaling pathways. Moreover, only about 2% of cell surface proteins are released from the surface by ectodomain shedding, indicating that cells selectively shed their protein ectodomains. This review will describe the molecular and cellular mechanisms of ectodomain shedding, and discuss its major functions in lung development and disease.

Report of the ECCO workshop on anti-TNF therapy failures in inflammatory bowel diseases: biological roles and effects of TNF and TNF antagonists

This second section of the first ECCO pathogenesis workshop on anti-TNF therapy failures in inflammatory bowel diseases addresses the biological roles of TNFα and the effects and mechanisms of action of TNFα antagonists. Mechanisms underlying their failure, including induction of TNF-independent inflammatory pathways and phenomena of paradoxical inflammation are discussed.

Assessment of pre-diagnosis biomarkers of immune activation and inflammation: insights on the etiology of lymphoma

The DNA-modifying processes that are involved in B lymphocyte activation, somatic hypermutation (SHM), and IgH class switch recombination (CSR) have the potential to lead to genetic errors that lead to the genesis of B cell cancers, such as lymphoma. Given the potential contribution of these immune mechanisms to the development of cancer, assessment of the expression of cytokines, and other immune stimulatory molecules that drive B cell activation, prior to lymphoma diagnosis, may provide insights into the etiology of these cancers. Here, we review studies that have examined prediagnosis protein biomarkers for non-Hodgkin lymphoma (NHL), both AIDS-related NHL, as well as NHL seen in immunocompetent populations. Overall, these studies provide support for the notion that B cell hyper-activation is elevated preceding the appearance of AIDS-NHL, particularly those forms of AIDS-NHL that are not driven by EBV infection and that presumably arise from errors in IgH CSR and SHM. In more limited studies, it appears that dysregulation of cytokine production also precedes the diagnosis of NHL in HIV-negative persons. The availability of prediagnosis serum/plasma from cohort studies provides unique opportunities for proteomic approaches to identify novel prediagnosis etiologic biomarkers for NHL.

Elevated endotoxin levels in non-alcoholic fatty liver disease

Background

Emerging data indicate that gut-derived endotoxin may contribute to low-grade systemic inflammation in insulin resistant states. This study aimed to examine the importance of serum endotoxin and inflammatory markers in non-alcoholic fatty liver disease (NAFLD) patients, with and without type 2 diabetes mellitus (T2DM), and to explore the effect of treatment with a lipase inhibitor, Orlistat, on their inflammatory status.

Methods

Fasted serum from 155 patients with biopsy proven NAFLD and 23 control subjects were analysed for endotoxin, soluble CD14 (sCD14), soluble tumour necrosis factor receptor II (sTNFRII) and various metabolic parameters. A subgroup of NAFLD patients were re-assessed 6 and 12 months after treatment with diet alone (n = 6) or diet plus Orlistat (n = 8).

Results

Endotoxin levels were significantly higher in patients with NAFLD compared with controls (NAFLD: 10.6(7.8, 14.8) EU/mL; controls: 3.9(3.2, 5.2) EU/mL, p < 0.001); NAFLD alone produced comparable endotoxin levels to T2DM (NAFLD: T2DM: 10.6(5.6, 14.2) EU/mL; non-diabetic: 10.6(8.5, 15.2) EU/mL), whilst a significant correlation between insulin resistance and serum endotoxin was observed (r = 0.27, p = 0.008). Both sCD14 (p < 0.01) and sTNFRII (p < 0.001) increased with severity of fibrosis. A positive correlation was also noted between sTNFRII and sCD14 in the NAFLD subjects (r = 0.29, p = 0.004).

Sub-cohort treatment with Orlistat in patients with NAFLD showed significant decreases in ALT (p = 0.006), weight (p = 0.005) and endotoxin (p = 0.004) compared with the NAFLD, non-Orlistat treated control cohort at 6 and 12 months post therapy, respectively.

Conclusions

Endotoxin levels were considerably increased in NAFLD patients, with marked increases noted in early stage fibrosis compared with controls. These results suggest elevated endotoxin may serve as an early indicator of potential liver damage, perhaps negating the need for invasive liver biopsy. As endotoxin may promote insulin resistance and inflammation, interventions aimed at reducing endotoxin levels in NAFLD patients may prove beneficial in reducing inflammatory burden.

Discovery of novel human transcript variants by analysis of intronic single-block EST with polyadenylation site

BACKGROUND

Alternative polyadenylation sites within a gene can lead to alternative transcript variants. Although bioinformatic analysis has been conducted to detect polyadenylation sites using nucleic acid sequences (EST/mRNA) in the public databases, one special type, single-block EST is much less emphasized. This bias leaves a large space to discover novel transcript variants.

RESULTS

In the present study, we identified novel transcript variants in the human genome by detecting intronic polyadenylation sites. Poly(A/T)-tailed ESTs were obtained from single-block ESTs and clustered into 10,844 groups standing for 5,670 genes. Most sites were not found in other alternative splicing databases. To verify that these sites are from expressed transcripts, we analyzed the supporting EST number of each site, blasted representative ESTs against known mRNA sequences, traced terminal sequences from cDNA clones, and compared with the data of Affymetrix tiling array. These analyses confirmed about 84% (9,118/10,844) of the novel alternative transcripts, especially, 33% (3,575/10,844) of the transcripts from 2,704 genes were taken as high-reliability. Additionally, RT-PCR confirmed 38% (10/26) of predicted novel transcript variants.

CONCLUSION

Our results provide evidence for novel transcript variants with intronic poly(A) sites. The expression of these novel variants was confirmed with computational and experimental tools. Our data provide a genome-wide resource for identification of novel human transcript variants with intronic polyadenylation sites, and offer a new view into the mystery of the human transcriptome.

Chronic antigenic stimuli as a possible explanation for the immunodepression caused by liver cirrhosis

The objectives of this work were the analysis of the functional characteristics of circulating monocytes and T lymphocytes in patients with liver cirrhosis, and evaluation of the relationship with an increased exposure to antigens due to bacterial translocation. Forty patients with liver cirrhosis (20 with compensated cirrhosis and 20 with ascitic decompensation) and 20 healthy control subjects were studied. Bacterial translocation was evaluated by serum levels of lipopolysaccharide binding protein (LBP). Macrophage activation was studied by CD40 antigen expression. T lymphocytes were analysed for activation (CD25(+), CD122(+)), effector function (CD8(+)CD45RO(+)CD57(+)), apoptosis (CD95(+)) and regulatory abilities, either by analysis of the membrane expression of co-stimulatory molecules CD80, CD86 and CD28, or by quantification of regulatory T cells CD4(+)CD25(high)forkhead box P3 (FoxP3). The percentage of activated monocytes and T lymphocytes in patients was increased significantly. The proportions of effector senescent cells and of those near to apoptosis were also significantly higher. With respect to these proportions, there were no significant differences between patients in function of the presence or absence of decompensation or in function of the increased or normal values of LBP. Conversely, those patients with elevated levels of LBP presented a significantly higher frequency of regulatory T cells than those with normal levels. In conclusion, patients with liver cirrhosis showed an intensive activation state with a higher percentage of cells committed to activation-induced death, even in non-advanced stages. It is possible that bacterial permeability and endotoxaemia contribute to the expansion of those lymphocyte populations implicated in the prevention of a more severe antigen-induced immunopathology.

Increased soluble tumor necrosis factor-alpha receptors in patients with major depressive disorder

AIM

Several lines of evidence suggest that major depressive disorder is associated with an inflammatory status. Tumor necrosis factor-alpha has been investigated as a potential molecular target in mood disorders. Tumor necrosis factor-alpha exerts its activity through binding to specific cell membrane receptors named as TNFR1 and TNFR2. The aim of the present study was to investigate soluble plasma TNFR1 (sTNFR1) and TNFR2 levels (sTNFR2) in major depressive disorder patients.

METHODS

Female outpatients with major depressive disorder (n = 30) were compared with a healthy control group (n = 19). Severity of depressive symptoms was evaluated on Beck Depression Inventory; post-traumatic stress disorder (PTSD) symptoms were evaluated on PTSD Checklist-Civilian Version; and childhood abuse and neglect on the Childhood Trauma Questionnaire. Plasma tumor necrosis factor-alpha and its soluble receptors were measured by ELISA.

RESULTS

Patients had no changes in tumor necrosis factor-alpha concentrations but did have increased sTNFR1 (P < 0.001) and sTNFR2 (P < 0.001) levels compared to controls. Plasma level of sTNFR1 was positively predicted by age (B = 0.25, P = 0.05) and PTSD-like symptoms (B = 0.41, P = 0.002) and plasma levels of sTNFR2 by depression severity (B = 0.67, P < 0.001).

CONCLUSIONS

Soluble tumor necrosis factor-alpha receptors could be reliable markers of inflammatory activity in major depression.

Effect of probiotic treatment on deranged neutrophil function and cytokine responses in patients with compensated alcoholic cirrhosis

BACKGROUND/AIM

Endotoxaemia contributes to neutrophil dysfunction, infection risk and mortality in patients with alcoholic cirrhosis. As probiotics may decrease Gram-negative gut organisms, we hypothesised that probiotic treatment would restore neutrophil function.

METHODS

In an open-label study, patients with alcoholic cirrhosis (n=12) received Lactobacillus casei Shirota (6.5 x 10(9)) 3 times daily for 4 weeks. Data were compared to healthy controls (n=13) and cirrhotic patients (n=8) who did not receive probiotics. Neutrophil oxidative burst, phagocytosis, toll-like-receptor (TLR) expression, plasma cytokines and ex vivo endotoxin-stimulated cytokine production were measured.

RESULTS

Baseline neutrophil phagocytic capacity in patients was significantly lower compared to healthy controls (73% versus 98%, p<0.05), but normalised at the end of the study (n=10, 100%, p<0.05). No improvement was seen in disease controls. Soluble TNF-receptor (sTNFR)-1 and-2 and interleukin (IL)10 were significantly elevated in patients' plasma but did not change during the study. Ex vivo endotoxin-stimulated levels of sTNFR1, sTNFR2 and IL10 were significantly lower at the end of the study (p<0.05). TLR2, 4 and 9 were overexpressed in patients. TLR4 expression normalised by the end of the study.

CONCLUSIONS

Our data provide a proof-of-concept that probiotics restore neutrophil phagocytic capacity in cirrhosis, possibly by changing IL10 secretion and TLR4 expression, warranting larger randomised controlled and mechanistic studies.

Dysferlin deficiency enhances monocyte phagocytosis: a model for the inflammatory onset of limb-girdle muscular dystrophy 2B

Dysferlin deficiency causes limb-girdle muscular dystrophy type 2B (LGMD2B; proximal weakness) and Miyoshi myopathy (distal weakness). Muscle inflammation is often present in dysferlin deficiency, and patients are frequently misdiagnosed as having polymyositis. Because monocytes normally express dysferlin, we hypothesized that monocyte/macrophage dysfunction in dysferlin-deficient patients might contribute to disease onset and progression. We therefore examined phagocytic activity, in the presence and absence of cytokines, in freshly isolated peripheral blood monocytes from LGMD2B patients and in the SJL dysferlin-deficient mouse model. Dysferlin-deficient monocytes showed increased phagocytic activity compared with control cells. siRNA-mediated inhibition of dysferlin expression in the J774 macrophage cell line resulted in significantly enhanced phagocytosis, both at baseline and in response to tumor necrosis factor-alpha. Immunohistochemical analysis revealed positive staining for several mononuclear cell activation markers in LGMD2B human muscle and SJL mouse muscle. SJL muscle showed strong up-regulation of endocytic proteins CIMPR, clathrin, and adaptin-alpha, and LGMD2B muscle exhibited decreased expression of decay accelerating factor, which was not dysferlin-specific. We further showed that expression levels of small Rho family GTPases RhoA, Rac1, and Cdc 42 were increased in dysferlin-deficient murine immune cells compared with control cells. Therefore, we hypothesize that mild myofiber damage in dysferlin-deficient muscle stimulates an inflammatory cascade that may initiate, exacerbate, and possibly perpetuate the underlying myofiber-specific dystrophic process.

Neutrophil serine proteases fine-tune the inflammatory response

Neutrophil serine proteases are granule-associated enzymes known mainly for their function in the intracellular killing of pathogens. Their extracellular release upon neutrophil activation is traditionally regarded as the primary reason for tissue damage at the sites of inflammation. However, studies over the past several years indicate that neutrophil serine proteases may also be key regulators of the inflammatory response. Neutrophil serine proteases specifically process and release chemokines, cytokines, and growth factors, thus modulating their biological activity. In addition, neutrophil serine proteases activate and shed specific cell surface receptors, which can ultimately prolong or terminate cytokine-induced responses. Moreover, it has been proposed that these proteases can impact cell viability through their caspase-like activity and initiate the adaptive immune response by directly activating lymphocytes. In summary, these studies point to neutrophil serine proteases as versatile mediators that fine-tune the local immune response and identify them as potential targets for therapeutic interventions.

Relationships between markers of inflammation, severity of injury, and clinical outcomes in hemorrhagic shock

This study was performed to investigate the relationships between markers of inflammation in serum (interleukin-6 [IL-6], interleukin-10 [IL-10], and granulocyte elastase [GE]), severity of injury, and clinical outcomes, and to evaluate the predictive value of these markers for major complications and mortality. This study, which was conducted between August 2003 and May 2005, examined patients older than 16 y who were admitted to the Emergency Unit of the Uludag University Medical School within 12 h after trauma, and who had traumatic hemorrhagic shock (THS) at admission. Three groups were established: the THS group (n=20), the pure hemorrhagic shock (PHS) group (n=20), and the healthy control group (n=20). Demographic data were recorded for all subjects, and blood samples were taken for lactate, base excess, GE, IL-6, and IL-10 measurements. The Glasgow Coma Score, the Revised Trauma Score, the Injury Severity Score, the New Injury Severity Score, and the Trauma Score-Injury Severity Score were calculated; complications and final clinical outcomes were monitored. A total of 35 men and 25 women were included in the study; mean patient age was 41+/-17 y. In the THS group, scores were as follows: Revised Trauma Score, 10.2+/-2.2; Trauma Score-Injury Severity Score, 0.86+/-0.2; Injury Severity Score, 24.8+/-9.0; and New Injury Severity Score, 32.7+/-9.0. IL-6, IL-10, lactate, and base excess levels in the THS group were significantly higher than those in the PHS and healthy control groups. The serum GE level of the THS group was significantly higher than that of the healthy control group, but it did not differ significantly from that of the PHS group. Complications such as sepsis, acute respiratory distress syndrome, and multiple organ failure occurred in 50% of the THS group and in 20% of the PHS group. Mortality was 30% in the THS group and 10% in the PHS group. In the THS group, no significant differences were noted between markers of inflammation and trauma scores of patients who died and those who survived. The investigators concluded that although the levels of markers of inflammation increased in THS patients, they were inadequate for predicting mortality and the development of complications such as acute respiratory distress syndrome, multiple organ failure, and sepsis. A larger study based on the use of serial marker measurements is warranted.