Proteome profile of neutrophils from a transgenic diabetic pig model shows distinct changes

INS^C94Y transgenic pigs develop a stable diabetic phenotype early after birth and therefore allow studying the influence of hyperglycemia on primary immune cells in an early stage of diabetes mellitus in vivo. Since immune response is altered in diabetes mellitus, with deviant neutrophil function discussed as one of the possible causes in humans and mouse models, we investigated these immune cells in INS^C94Y transgenic pigs and wild type controls at protein level. A total of 2371 proteins were quantified by label-free LC-MS/MS. Subsequent differential proteome analysis of transgenic animals and controls revealed clear differences in protein abundances, indicating a deviant behavior of granulocytes in the diabetic state. Interestingly, abundance of myosin regulatory light chain 9 (MLC-2C) was increased 5-fold in cells of diabetic pigs. MLC-2C directly affects cell contractility by regulating myosin ATPase activity, can act as transcription factor and was also associated with inflammation. It might contribute to impaired neutrophil cell adhesion, migration and phagocytosis. Our study provides novel insights into proteome changes in neutrophils from a large animal model for permanent neonatal diabetes mellitus and points to dysregulation of neutrophil function even in an early stage of this disease. Data are available via ProteomeXchange with identifier PXD017274. SIGNIFICANCE: Our studies provide novel basic information about the neutrophil proteome of pigs and contribute to a better understanding of molecular mechanisms involved in altered immune cell function in an early stage diabetes. We demonstrate proteins that are dysregulated in neutrophils from a transgenic diabetic pig and have not been described in this context so far. The data presented here are highly relevant for veterinary medicine and have translational quality for diabetes in humans.

Isolation of Neutrophils from Nonhuman Species

The development of new advances in understanding the role of neutrophils in inflammation requires effective procedures for isolating and purifying neutrophils. Methods for isolating human neutrophils are fairly standard, and some are covered in other chapters of this volume and previous editions. However, procedures for isolating neutrophils from nonhuman species used to model human diseases vary from those used in isolating human neutrophils and are not as well developed. Since neutrophils are highly reactive and sensitive to small perturbations, the methods of isolation are important to avoid isolation technique-induced alterations in cell function. We present methods here for reproducibly isolating highly purified neutrophils from large animal models (bovine, equine, ovine), small animal models (murine and rabbit), and nonhuman primates (cynomolgus macaques) and describe optimized details for obtaining the highest cell purity, yield, and viability.

Applying Osteosarcoma Immunology to Understand Disease Progression and Assess Immunotherapeutic Response

Osteosarcoma, the most common malignant bone tumor in children and adolescents, remains a complicated disease to treat; no new treatments have been developed in more than three decades. Due to the importance of the immune system in osteosarcoma disease progression, immunotherapeutic strategies have been explored to potentially improve long-term survival. However, most immunotherapeutics have not reached the level of success hoped would occur in this disease. Understanding the immune system in osteosarcoma will be key to optimizing treatments and improving patient outcomes. Therefore, immunophenotyping can be used as a very powerful tool to help better understand the complexity of the immune response seen in osteosarcoma and in the use of immunotherapy in this malignancy. This book chapter will provide an overview of the known immune responses seen in this disease and potential developments for the future of immunophenotyping. Indeed, it appears that being able to track the immune system throughout the disease and treatment of patients with osteosarcoma could allow for a personalized approach to immunotherapy.

The Role of Neutrophils in the Immune System: An Overview

Neutrophils, also known as polymorphonuclear neutrophils (PMNs), have long been considered as the short-lived, nonspecific white cells that form pus-and also happen to kill invading microbes. Indeed, neutrophils were often neglected (and largely not considered) as immune cells. This historic view of neutrophils has changed considerably over the past several decades, and we now know that in addition to playing the predominant role in the clearance of bacteria and fungi, they have a major role in shaping the host response to infection and immune system homeostasis. The change in our view of the role of neutrophils in the immune system has been due in large part to the study of these cells in vitro. Such work has been made possible by new and/or improved methods and approaches used to investigate neutrophils. These methods are the focus of this volume.

Toll-like receptor 4 protects against irradiation-induced hematopoietic injury by promoting granulopoiesis and alleviating marrow adipogenesis

Irradiation induces severe damage in the hematopoietic system, which leads to bone marrow hyperplasia, pancytopenia, and aggravated tissue formation in bone marrow. Studies have shown that Toll-like receptor 4 (TLR4) has a protective effect against irradiation, but the underlying mechanism remains unclear. In this study, we used a TLR4 knockout (TLR4^-/-) mouse irradiation model and found that the white blood cell and platelet counts in the peripheral blood of TLR4^-/- mice recovered slowly after irradiation, with bone marrow hyperplasia and increased mortality. Additionally, we found that the proportion of CD11b⁺Gr1⁺ granulocytes in the peripheral blood and bone marrow of TLR4^-/- mice was lower than that of wild-type mice after irradiation. Further, we found that the expression of NADPH Oxidases (NOXs) in the bone marrow was down-regulated after irradiation of TLR4^-/- mice, and administration of the NOXs inhibitor VAS2870 reduced the proportion of CD11b⁺Gr1⁺ cells in the bone marrow and peripheral blood of wild-type mice after irradiation. Irradiation induced severe marrow adipocytes accumulation in TLR4^-/- mice, TLR4 ligand lipopolysaccharide promoted proliferation and inhibited adipogenic differentiation of mesenchymal stromal cells. In summary, our data suggest that TLR4 promotes myeloid hyperplasia by up-regulating the expression of NOXs after irradiation, prohibits marrow adipogensis and increases the tolerance of mice to irradiation.

Determination of Subset-Restricted Anti-neutrophil Cytoplasmic Antibodies (ANCA) by Immunofluorescence Cytochemistry

Neutrophils have long been considered a homogeneous cell type where all circulating cells of a particular individual express the same proteins. Lately, however, this view is changing and distinct neutrophil subsets, defined by the presence or absence of different proteins, are being increasingly recognized. At least two separate protein markers, CD177 and Olfactomedin-4 (OLFM4) are known to be expressed by some, but not all, circulating neutrophils of a given individual. We recently described the existence of subset-restricted serum autoantibodies targeting OLFM4; these were discovered during clinical testing for anti-neutrophil cytoplasmic antibodies (ANCAs). ANCA testing is part of the clinical examinations routinely carried out to support diagnosis of suspected autoimmune conditions, especially vasculitis. Positive sera typically react with all neutrophils from a single donor, whereas subset-restricted ANCA sera (such as those containing anti-OLFM4 antibodies) only react with a fraction of neutrophils. Described in this chapter is an indirect immunofluorescence (IIF) approach to test human sera for the presence of subset-restricted ANCA as well as instructions for costaining experiments using sera and purified antibodies directed against established subset markers.

The medicinal leech as a valuable model for better understanding the role of a TLR4-like receptor in the inflammatory process

Despite extensive investigation focused on both the molecular characteristics and the expression level of Toll-like receptors (TLRs) during the inflammatory response in vertebrates, few data are available in the literature on the role of these proteins in invertebrate's immune response. Here, we propose the medicinal leech as a valuable model to better elucidate the role of TLR4 and its related products, such as tumor necrosis factor (TNF-α), after activation of the leech peripheral immune system with the endogenous medicinal leech recombinant allograft inflammatory factor-1 (rHmAIF-1) or with an exogenous stimulus, such as lipopolysaccharide (LPS). Our results indicate that activated macrophages (HmAIF-1⁺) and granulocytes (CD11b⁺) express both TLR4 and its coreceptor CD14. Moreover, functional studies performed by injecting a cyanobacterium selective TLR4 antagonist CyP demonstrated that only the TLR4 pathway was blocked, while the immune response caused by lipoteichoic acid (LTA) treatment is not affected. These results are consistent with literature on vertebrates, indicating that TLR4 functions as a LPS receptor while the recognition of LTA may involve other pathways.

Tbo-filgrastim versus filgrastim for stem cell mobilization and engraftment in autologous hematopoietic stem cell transplant patients: A retrospective review

INTRODUCTION

Filgrastim, a granulocyte colony-stimulating factor, is commonly used in autologous hematopoietic stem cell transplants (HSCTs) to assist with peripheral blood progenitor cell (PBPC) collection and to support stem cell engraftment. In the United States, tbo-filgrastim is approved under its own Biologic License Application and is limited to a single indication excluding the HSCT population.

METHODS

Approximately one year after a system-wide formulary change to tbo-filgrastim for all on- and off-label indications, our institution conducted an IRB-approved retrospective comparison of tbo-filgrastim to filgrastim in the autologous HSCT setting. The study included 71 patients who received an autologous HSCT from 1 January 2013 to 31 December 2016 with a documented administration of tbo-filgrastim or filgrastim.

RESULTS

There were no statistically significant differences noted on CD34 + counts during stem cell mobilization, neutrophil engraftment, infection rates during the engraftment phase, nor duration of hospitalization during the engraftment phase. More patients in the tbo-filgrastim group received plerixafor per protocol resulting in more patients meeting their PBPC collection goal in one day with fewer collection days overall, a result potentially confounded by institutional protocol changes. Utilizing tbo-filgrastim offered an average cost savings per patient of $2664.26 ($1907.33 for PBPC mobilization and $756.93 for stem cell engraftment) when comparing dollars spent on granulocyte colony-stimulating factor products only.

CONCLUSION

Tbo-filgrastim demonstrates comparable efficacy with a cost savings benefit compared to filgrastim for autologous PBPC mobilization and stem cell engraftment.

GILZ restrains neutrophil activation by inhibiting the MAPK pathway

Glucocorticoid-induced leucine zipper (GILZ) exerts anti-inflammatory effects on the immune cells. However, less is known about GILZ function in neutrophils. We aimed to define the specific role of GILZ in basal neutrophil activity during an inflammatory response. GILZ knockdown resulted in a persistent activation state of neutrophils, as evidenced by increased phagocytosis, killing activity, and oxidative burst in GILZ-knockout (KO) neutrophils. This enhanced response caused severe disease in a dinitrobenzene sulfonic acid (DNBS)-induced colitis model, where GILZ-KO mice had prominent granulocytic infiltrate and excessive inflammatory state. We used a Candida albicans intraperitoneal infection model to unravel the intracellular pathways affected by GILZ expression in activated neutrophils. GILZ-KO neutrophils had stronger ability to clear the infectious agent than the wild-type (WT) neutrophils, and there was more activation of the NOX2 (NADPH oxidase 2) and p47^phox proteins, which are directly involved in oxidative burst. Similarly, the MAPK pathway components, that is, ERK and p38, which are involved in the oxidative burst pathway, were highly phosphorylated in GILZ-KO neutrophils. Evaluation of GILZ expression kinetics during C. albicans infection revealed down-regulation that correlated inversely with the state of neutrophil activation, which was evaluated as oxidative burst. Overall, our findings define GILZ as a regulator of neutrophil functions, as its expression contributes to limiting neutrophil activation by reducing the activation of the signaling pathways that control the basal neutrophil functions. Controlling GILZ expression could help regulate a continuous inflammatory state that can result in chronic inflammatory and autoimmune diseases.

Targeting transcription factors in acute myeloid leukemia

Transcription factors recognize and bind to consensus sequence elements that are specific for each transcription factor, and the transcription factors then regulate downstream gene expression. In the bone marrow, transcription factors, such as C/EBPα, PU.1, and RUNX1, control essential genes to maintain the normal hematopoietic system. Dysregulation of transcription factors caused by gene mutations, chromosomal aberrations, or aberrant expression can lead to cancer, including acute myeloid leukemia. In the past, transcription factors were not considered "druggable" targets. However, a better understanding of the pathology of malignant tumors and mechanisms of transcriptional regulation has enabled us to develop novel therapeutic strategies that target transcription factors. In this review, we focus on transcription factors that play important roles in leukemogenesis and current efforts and prospects in the development of transcriptional therapy. We believe that such a therapeutic approach will benefit patients with cancers that involve acute myeloid leukemia in the near future.

Adsorption of Soluble Immunoglobulin-Type Adhesion Molecules to Cellulose Acetate Beads

Circulating levels of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular adhesion molecule-1 (sVCAM-1) are elevated in patients with inflammatory bowel disease. Cellulose acetate (CA) beads are used as carriers for granulocyte and monocyte (GM) adsorptive apheresis (GMA). We investigated the effect of CA beads on sICAM-1 and sVCAM-1 plasma concentrations in vitro. Because GM adsorption to CA beads increased with a rise in the incubation temperature in our previous study, peripheral blood was incubated with and without CA beads at 5, 25, 37, or 43 °C and plasma sICAM-1 and sVCAM-1 was measured. The sICAM-1 and sVCAM-1 concentrations in samples incubated with CA beads were significantly lower than those without CA beads at all four temperatures. However, no significant differences were observed both sICAM-1 and sVCAM-1 plasma levels at the four different temperatures after incubation with CA beads. These results suggest that independent of incubation temperature, sICAM-1 and sVCAM-1 are likely to adsorb CA beads. These molecules may be a new index for predicting the therapeutic effects of GMA.

Orchestration of epithelial-derived cytokines and innate immune cells in allergic airway inflammation

Allergic asthma, a chronic respiratory disease, is a leading worldwide health problem, which inflames and constricts the airways, leading to breathing difficulty. Many studies have focused on the pathogenesis contributed by the adaptive immune system, including CD4+ T lymphocytes in delayed type hypersensitivity and B cell-produced IgE in anaphylaxis. More recently, a focus on the airway mucosal barrier and the innate immune system has highlighted, in coordination with T and B cells, to initiate and establish disease. This review highlights the impacts of epithelial-derived cytokines and innate immune cells on allergic airway reactions.

Inhibition of arginase by CB-1158 blocks myeloid cell-mediated immune suppression in the tumor microenvironment

Background

Myeloid cells are an abundant leukocyte in many types of tumors and contribute to immune evasion. Expression of the enzyme arginase 1 (Arg1) is a defining feature of immunosuppressive myeloid cells and leads to depletion of L-arginine, a nutrient required for T cell and natural killer (NK) cell proliferation. Here we use CB-1158, a potent and orally-bioavailable small-molecule inhibitor of arginase, to investigate the role of Arg1 in regulating anti-tumor immunity.

Methods

CB-1158 was tested for the ability to block myeloid cell-mediated inhibition of T cell proliferation in vitro, and for tumor growth inhibition in syngeneic mouse models of cancer as a single agent and in combination with other therapies. Tumors from animals treated with CB-1158 were profiled for changes in immune cell subsets, expression of immune-related genes, and cytokines. Human tumor tissue microarrays were probed for Arg1 expression by immunohistochemistry and immunofluorescence. Cancer patient plasma samples were assessed for Arg1 protein and L-arginine by ELISA and mass spectrometry, respectively.

Results

CB-1158 blocked myeloid cell-mediated suppression of T cell proliferation in vitro and reduced tumor growth in multiple mouse models of cancer, as a single agent and in combination with checkpoint blockade, adoptive T cell therapy, adoptive NK cell therapy, and the chemotherapy agent gemcitabine. Profiling of the tumor microenvironment revealed that CB-1158 increased tumor-infiltrating CD8⁺ T cells and NK cells, inflammatory cytokines, and expression of interferon-inducible genes. Patient tumor samples from multiple histologies expressed an abundance of tumor-infiltrating Arg1⁺ myeloid cells. Plasma samples from cancer patients exhibited elevated Arg1 and reduced L-arginine compared to healthy volunteers.

Conclusions

These results demonstrate that Arg1 is a key mediator of immune suppression and that inhibiting Arg1 with CB-1158 shifts the immune landscape toward a pro-inflammatory environment, blunting myeloid cell-mediated immune evasion and reducing tumor growth. Furthermore, our results suggest that arginase blockade by CB-1158 may be an effective therapy in multiple types of cancer and combining CB-1158 with standard-of-care chemotherapy or other immunotherapies may yield improved clinical responses.

Glucocorticoid receptor number and affinity differ between peripheral blood mononuclear cells and granulocytes in domestic pigs

The aim of the present study was to characterize the number and affinity of glucocorticoid receptors (GR) in peripheral blood mononuclear cells (PBMC) and granulocytes of domestic pigs because glucocorticoid signaling is considered important for animal health and welfare. To investigate GR binding characteristics in intact porcine immune cells, blood samples of 6 castrated male pigs were collected via indwelling vein catheters. Porcine PBMC and granulocytes were isolated using two-layer density gradients, followed by radioligand binding assays to determine the number of GR sites per cell and the dissociation constant K_d as a measure for GR binding affinity. The present study revealed a greater number of GR sites per cell (P = 0.039) in PBMC (mean ± SEM: 1,953 ± 207 sites/cell) compared to granulocytes (1,561 ± 159 sites/cell) in domestic pigs. Furthermore, porcine PBMC had a higher GR binding affinity than porcine granulocytes (P = 0.003) as the dissociation constant K_d of PBMC (1.8 ± 0.2 nM) was lower than that of granulocytes (3.5 ± 0.4 nM). Our results point to differences in underlying mechanisms of glucocorticoid signaling in different porcine leukocyte populations.

Sequential therapy consisting of glucocorticoid infusions followed by granulocyte-monocyte absorptive apheresis in patients with severe alcoholic hepatitis

BACKGROUND

Activated leukocytes infiltrating the liver contribute to the provocation of alcoholic hepatitis. Glucocorticoid induces the demargination of leukocytes from the hepatic sinusoids, whereas granulocyte-monocyte absorptive apheresis (GMA) removes leukocytes from the circulation. Thus, the usefulness of a sequential therapy consisting of glucocorticoid infusions followed by GMA was evaluated in patients with severe alcoholic hepatitis.

METHODS

Patients with severe alcoholic hepatitis received intravenous injections of methylprednisolone (1,000 mg/day) for 3 or 4 days, and then GMA was performed every day for 3 days. Responders were defined as those with attenuated serum C-reactive protein (CRP) levels during the GMA procedures.

RESULTS

Ten consecutive patients were enrolled. At the baseline, the Japan alcoholic hepatitis scores were 9 in two patients and 10 or more in eight patients, and the Model for End-Stage Liver Disease scores ranged from 22 to 43. In all the patients, the peripheral neutrophil counts increased and the serum levels of CRP, aspartate aminotransferase, IL-6, IL-8, TNF-α, and intercellular adhesion molecule 1 decreased immediately after the glucocorticoid infusions. However, a rebound increase in the serum CRP levels was observed in all patients after discontinuation of glucocorticoid infusions, but the maximal values during the GMA procedures were lower than the baseline values. Six patients were rescued, whereas the remaining four patients died because of sepsis, pneumonia, pancreatitis, and renal failure.

CONCLUSIONS

Sequential therapy combining glucocorticoid infusion and GMA was useful for attenuating liver injuries in patients with severe alcoholic hepatitis by preventing rebound increases in inflammatory reactions after discontinuation of glucocorticoid infusions, except in patients with bacterial infections and/or multiple organ failure.

Immune roles of amphibian (Xenopus laevis) tadpole granulocytes during Frog Virus 3 ranavirus infections

Infections by Frog Virus 3 (FV3) and other ranaviruses (RVs) are contributing to the amphibian declines, while the mechanisms controlling anuran tadpole susceptibility and adult frog resistance to RVs, including the roles of polymorphonuclear granulocytes (PMNs) during anti-FV3 responses, remain largely unknown. Since amphibian kidneys represent an important FV3 target, the inability of amphibian (Xenopus laevis) tadpoles to mount effective kidney inflammatory responses to FV3 is thought to contribute to their susceptibility. Here we demonstrate that a recombinant X. laevis granulocyte colony-stimulating factor (G-CSF) generates PMNs with hallmark granulocyte morphology. Tadpole pretreatment with G-CSF prior to FV3 infection reduces animal kidney FV3 loads and extends their survival. Moreover, G-CSF-derived PMNs are resistant to FV3 infection and express high levels of TNFα in response to this virus. Notably, FV3-infected tadpoles fail to recruit G-CSFR expressing granulocytes into their kidneys, suggesting that they lack an integral inflammatory effector population at this site.

A flow-cytometric method to evaluate eosinophil-mediated uptake of probiotic Lactobacillus reuteri

Eosinophils are resident leukocytes of gut mucosa. Here we present a combined flow cytometric-antibiotic protection assay to identify mouse eosinophils capable of bacterial uptake, specifically, Gram-positive Lactobacillus reuteri, in studies performed ex vivo. The assay may be adapted for use in vivo.

Granulocyte and monocyte adsorptive apheresis ameliorates sepsis in rats

Background

Overwhelming activation of granulocytes and monocytes is central to inflammatory responses during sepsis. Granulocyte and monocyte adsorptive apheresis (GMA) is an extracorporeal leukocyte apheresis device filled with cellulose acetate beads and selectively adsorbs granulocytes and monocytes from the peripheral blood.

Methods

In this study, septic rats received the GMA treatment for 2 h at 18 h after cecal ligation and puncture.

Results

GMA selectively adsorbed activated neutrophils and monocytes from the peripheral blood, reduced serum inflammatory cytokine expression, and seemed to improve organ injuries and animal survival. GMA potentially reduced lung injury by alleviating the infiltration of inflammatory cells and the secretion of cytokines.

Conclusions

This study showed that selective granulocyte and monocyte adsorption with cellulose acetate beads might ameliorate cecal ligation and puncture (CLP)-induced sepsis and improve survival and organ function.

Effect of intravenous plasma transfusion on granulocyte and monocyte oxidative and phagocytic activity in dairy calves with failure of passive immunity

Plasma administration has been recommended in calves older than 48h with failure of passive immunity (FPI) to provide immunity consistent with adequate colostral ingestion. However, the protective serum immunoglobulin G (IgG) concentrations (≥1000mg/dL) of plasma derived IgG only lasts up to 12h. In addition to IgG, maternally derived colostral cells also confer immunity. The objective of the study was to determine the effect of intravenous plasma transfusion on granulocyte and monocyte oxidative and phagocytic activity in calves with FPI. Twenty-seven, one day-old, Jersey calves were assigned into 3 groups. The colostral (CL, N=9) group received 3L of colostrum once by oroesophageal tubing. Two other groups of calves received 1L of colostrum once by oroesophageal tubing and were assigned based on their health status (sick or non-sick) at 4days of age, as the sick-group (SG, N=7) or the non-sick (NG, N=11) groups. At 4days of age, the SG and NG groups were administered plasma intravenously at 30mL/kg. Granulocyte and monocyte oxidative and phagocytic activity was determined by flow cytometry. There was no significant difference in the granulocyte and monocyte oxidative or phagocytic activity among the 3 groups (P>0.05). Plasma administration had no significant effect on the oxidative or phagocytic activity of granulocytes or monocytes. In clinical practice, plasma administration for enhancing oxidative or phagocytic activity of granulocytes or monocytes, alone, might not be justified in calves with FPI.

The unique myelopoiesis strategy of the amphibian Xenopus laevis

Myeloid progenitors reside within specific hematopoietic organs and commit to progenitor lineages bearing megakaryocyte/erythrocyte (MEP) or granulocyte/macrophage potentials (GMP) within these sites. Unlike other vertebrates, the amphibian Xenopus laevis committed macrophage precursors are absent from the hematopoietic subcapsular liver and instead reside within their bone marrow. Presently, we demonstrate that while these frogs' liver-derived cells are unresponsive to recombinant forms of principal X. laevis macrophage (colony-stimulating factor-1; CSF-1) and granulocyte (CSF-3) growth factors, bone marrow cells cultured with CSF-1 and CSF-3 exhibit respectively archetypal macrophage and granulocyte morphology, gene expression and functionalities. Moreover, we demonstrate that liver, but not bone marrow cells possess erythropoietic capacities when stimulated with a X. laevis erythropoietin. Together, our findings indicate that X. laevis retain their MEP within the hematopoietic liver while sequestering their GMP to the bone marrow, thus marking a very novel myelopoietic strategy as compared to those seen in other jawed vertebrate species.

Impaired Blood Neutrophil Function in the Frequent Exacerbator of Chronic Obstructive Pulmonary Disease: A Proof-of-Concept Study

PURPOSE

The underlying biological mechanisms of the frequent exacerbator phenotype of COPD remain unclear. We compared systemic neutrophil function in COPD patients with or without frequent exacerbations.

METHODS

Whole blood from COPD frequent exacerbators (defined as ≥2 moderate-severe exacerbations in the previous 2 years) and non-exacerbators (no exacerbations in the preceding 2 years) was assayed for neutrophil function. Neutrophil function in healthy ex-smoking volunteers was also measured as a control (reference) group.

RESULTS

A total of 52 subjects were included in this study: 26 frequent exacerbators, 18 non-exacerbators and 8 healthy controls. COPD frequent exacerbators had blunted blood neutrophil fMLP-stimulated oxidative burst compared to both non-exacerbators (p < 0.01) and healthy controls (p < 0.001). There were no differences between COPD frequent exacerbators and non-exacerbators in blood neutrophil PMA-stimulated oxidative burst, but both COPD groups had reduced responses compared to healthy controls (p < 0.001). Bacterial-stimulated neutrophil degranulation was greater in frequent exacerbators than non-exacerbators (p < 0.05).

CONCLUSION

This study is the first to report aberrant receptor-mediated blood neutrophil function in the frequent exacerbator of COPD.

Time dependent apoptotic rates in the evolving coronary thrombus mass of myocardial infarction patients

AIM

To study the rate of apoptotic cell death in the process of thrombus evolution after plaque rupture in myocardial infarction.

METHODS

Paraffin embedded thrombosuction aspirates of 63 patients were stained with haematoxylin & eosin (H&E) to assess histologically the age of the thrombi: fresh (intact blood cells; <1day old), lytic (necrosis; 1-5days old) or organized (ingrowth of cells; >5days old). Presence of plaque constituents (atheroma including foam cells, cholesterol crystals calcifications and fibrous cap tissue) was also recorded. Immunohistochemical (double) stains with anti-caspase-3-antibody were used to visualize apoptosis and the cells involved. For the latter caspase-3 antibody was combined with cell-specific markers MPO (granulocytes), CD68 (macrophages), CD34 (endothelial cells), SMA-1 (smooth muscle cells) and a Feulgen stain (DNA). Second, the rate of apoptosis was evaluated in relation to the age of the thrombi. Platelet apoptosis was further evaluated with the use of TEM.

RESULTS

From a total of 63 aspirates, plaque constituents were found in 33 of the aspirates, and in 15 of them lipid rich plaque tissue was the sole component. Age classification of all thrombus containing aspirates (n=48) resulted in 12 fresh (25%), 18 lytic (37.5%) and 18 organized (37.5%) thrombi. Apoptosis was more extensive in lytic thrombi than in fresh or organized thrombi (P<0.0001). Plaque-containing aspirates showed more apoptosis than aspirates without plaque (P<0.05). Immuno staining with caspase-3 antibody in combination with cell-specific markers showed that apoptosis was most extensive in MPO+ granulocytes. Caspase-3-positive platelets (CD61+ anucleate particles) were most abundant in lytic thrombi. Apoptosis in platelets was confirmed by ultrastructure.

CONCLUSION

This study demonstrated a significant association between thrombus age and occurrence of apoptosis of granulocytes and also platelets, with highest rates in (fragile) lytic thrombi. We propose that apoptotic cell death in athero thrombosis could potentially serve as a biomarker for thrombus instability.

Novel Blood Purification System for Regulating Excessive Immune Reactions in Severe Sepsis and Septic Shock: An Ex Vivo Pilot Study

Promising results have been reported with blood purification as adjuvant treatment; however, the immunological mechanisms remain unclear. We have been developing a new blood purification system for regulating excessive immune reactions in severe sepsis and septic shock using a granulocyte adsorbing column (Adacolumn [Ada]), and a cytokine-adsorbing hemofilter (AN69ST hemofilter [AN69]). Fresh porcine blood was circulated for 6 h in five experimental groups including Ada and AN69 to assess the effects of leukocyte adsorption, phagocytic activity and adhesiveness of granulocytes. In the present study, we found that Ada mainly adsorbed granulocytes and monocytes, but not lymphocytes. The phagocytic activity level of granulocytes decreased, and adhesiveness increased, but the number of CD11b-positive cells markedly decreased in the current system. Elevated cytokine levels (IL-1β, IL-8 and IL-10) at the outlet of Ada were significantly lower than at the outlet of AN69 due to cytokine adsorption. Further studies are needed to better understand cellular interactions.

Haematopoiesis in Marsupials

Marsupials are a group of mammals that give birth to immature young lacking mature immune tissues at birth, and are unable to mount their own specific immune defence. Their immune tissues develop in a non-sterile ex-utero environment unlike that of eutherian mammals such as ourselves. Marsupials are therefore ideal models for studying the development of immune tissues, in particular haematopoiesis, yet relatively little has been investigated. Most studies have been restricted to histological or immunohistological studies, however some factors likely to be involved, based on eutherian studies in haematopoiesis, have been isolated and characterised, including a few key markers, and some cell signaling and regulation molecules, mostly involved in lymphocytopoiesis. However the role of many molecules in haematopoiesis is largely presumed. We currently lack much of the rudimentary information regarding time of appearance and expression levels of these molecules, and no functional studies have been conducted. This paper reviews our knowledge of marsupial haematopoiesis to date, and highlights the need for future research in marsupials to gain further insights into the evolution of haematopoiesis.

In Vitro Differentiation of Mouse Granulocytes

Granulocytes are central players of the immune system and, once activated, a tightly controlled balance between effector functions and cell removal by apoptosis guarantees maximal host benefit with least possible collateral damage to healthy tissue.Granulocytes are terminally differentiated cells that cannot be maintained in culture for prolonged times. Isolating primary granulocytes is inefficient and challenging when working with mice, and especially so for the lowly abundant eosinophil and basophil subtypes. Here we describe an in vitro protocol to massively expand mouse derived myeloid progenitors and to differentiate them "on demand" and in large numbers into mature neutrophils or basophils.