Blood Polymorphonuclear Leukocytes Research Articles

Association of reduced heme oxygenase-1 with excessive Toll-like receptor 4 expression in peripheral blood mononuclear cells in Behçet's disease

IntroductionToll-like receptors (TLRs) mediate signaling that triggers activation of the innate immune system, whereas heme oxygenase (HO)-1 (an inducible heme-degrading enzyme that is induced by various stresses) suppresses inflammatory responses. We investigated the interaction between TLR and HO-1 in an inflammatory disorder, namely Behçet's disease.MethodsThirty-three patients with Behçet's disease and 30 healthy control individuals were included in the study. Expression levels of HO-1, TLR2 and TLR4 mRNA were semiquantitatively analyzed using a real-time PCR technique, and HO-1 protein level was determined by immunoblotting in peripheral blood mononuclear cells (PBMCs) and polymorphonuclear leukocytes. In some experiments, cells were stimulated with lipopolysaccharide or heat shock protein-60; these proteins are known to be ligands for TLR2 and 4.ResultsLevels of expression of HO-1 mRNA were significantly reduced in PBMCs from patients with active Behçet's disease, whereas those of TLR4, but not TLR2, were increased in PBMCs, regardless of disease activity. Moreover, HO-1 expression in PBMCs from patients with Behçet's disease was repressed in the presence of either lipopolysaccharide or heat shock protein-60.ConclusionThe results suggest that upregulated TLR4 is associated with HO-1 reduction in PBMCs from patients with Behçet's disease, leading to augmented inflammatory responses.

Induction of Necrotizing Funisitis by Fetal Administration of Intravenous Granulocyte-Colony Stimulating Factor and Intra-Amniotic Endotoxin in Premature Fetal Sheep

The purpose of the present study was to determine whether experimental intrauterine inflammation could induce necrotizing funisitis, a severe, chronic inflammation of the umbilical cord. Fetuses, randomly divided into four groups (n = 4 each), were infused with 50 mug/d of granulocyte-colony stimulating factor (G-CSF) intravenously on d 125-129 of gestation (G-CSF group), 20 mg of endotoxin into the amniotic cavity on d 127 gestation (endotoxin group), both G-CSF and endotoxin (G-CSF + endotoxin group), or only saline (control group). On d 130 of gestation, the umbilical cords were processed for histologic analysis, scored for degree of inflammation, and compared statistically. At birth, the blood polymorphonuclear leukocyte counts in G-CSF and G-CSF + endotoxin groups were significantly higher than those in endotoxin and control groups (p < 0.05). The inflammatory score of the umbilical cord in G-CSF + endotoxin group was significantly higher than those in the other three groups (p < 0.05). All the fetuses in G-CSF + endotoxin group had necrotizing funisitis, but none of the fetuses in the other three groups developed this condition. An increase in blood polymorphonuclear leukocytes before their activation in the umbilical cord is probably essential for experimentally inducing necrotizing funisitis.

N-acetylcysteine amide (AD4) attenuates oxidative stress in beta-thalassemia blood cells

Many aspects of the pathology in β-hemoglobinopathies (β-thalassemia and sickle cell anemia) are mediated by oxidative stress. In the present study we tested a novel thiol compound, N-acetylcysteine amide (AD4), the amide form of N-acetyl cysteine (NAC) for its antioxidant effects. Using flow-cytometry, we showed that in vitro treatment of blood cells from β-thalassemic patients with AD4 elevated the reduced glutathione (GSH) content of red blood cells (RBC), platelets and polymorphonuclear (PMN) leukocytes, and reduced their ROS. These effects resulted in a significant reduced sensitivity of thalassemic RBC to hemolysis and phagocytosis by macrophages. Intra-peritoneal injection of AD4 to β-thalassemic mice (150 mg/kg) reduced the parameters of oxidative stress (p<0.001). Our results show the superiority of AD4, compared to NAC, in reducing oxidative stress markers in thalassemic cells both in vitro and in vivo.

Bacteriophage preparation inhibition of reactive oxygen species generation by endotoxin-stimulated polymorphonuclear leukocytes

It has been known that administration of antibiotics may lead to excessive release of bacterial endotoxins and complicate clinical course of patients with Gram-negative infections. This concern may also apply to phages. Endotoxin may in turn activate neutrophils to produce reactive oxygen species (ROS) that are believed to play an important role in the pathogenesis of multiple organ dysfunction in the course of sepsis.We showed that a purified T4 phage preparation with low-endotoxin content could significantly diminish the luminol-dependent chemiluminescence (CL) of peripheral blood polymorphonuclear leukocytes (PMNs) both stimulated by lipopolysaccharides (LPSs) isolated from different Escherichia coli strains. This effect was also observed for live bacteria used for PMNs stimulation and was independent of bacterial susceptibility for T4-mediated lysis. Our data suggest, that phage-mediated inhibition of LPS- or bacteria-stimulated ROS production by PMNs may be attributed not only to phage–PMNs interactions, but also to phage–LPS interactions and bacterial lysis (in case of homologous phage). Interestingly, the T4 preparation did not influence ROS formation by PMNs stimulated with PMA. This suggests that the observed phenomena are also dependent upon the nature of activator.Bacteriophage-mediated inhibition of ROS formation by cells exposed to endotoxin provides new evidence for possible interactions between phages and mammalian cells. It helps in understanding the role of phages in our environment and may also be of important clinical significance.

Oxidative stress in red blood cells, platelets and polymorphonuclear leukocytes from patients with myelodysplastic syndrome

Low-risk myelodysplastic syndrome (MDS) is characterized by cytopenia, mainly anemia, because of ineffective hematopoiesis. Some of the patients with ineffective erythropoiesis, with or without ring sideroblasts in their bone marrow, develop severe anemia requiring frequent blood transfusions and consequently develop iron overload. Excess free iron in cells catalyses the generation of reactive oxygen species (ROS) that cause cell and tissue damage. Using flow cytometry techniques, we compared the oxidative status of red blood cells (RBC), platelets and neutrophils in 14 MDS patients with those of normal donors. The results show that ROS were higher while reduced glutathione (GSH) was lower in their RBC and platelets compared with normal cells. In neutrophils, no difference was found in ROS, while the GSH levels were lower. A correlation (r = 0.6) was found between serum ferritin levels of the patients and the ROS in their RBC and platelets. The oxidative stress was ameliorated by a short incubation with the iron-chelators, the deferrioxamine and deferiprone or with antioxidants such as N-acetylcysteine, suggesting that MDS patients might benefit from treatment with iron-chelators and antioxidants.

Phagocytic Function of Human Blood Polymorphonuclear Leukocytes in the Presence of Carrageenan, a Potential Vaginal Microbicide

Carrageenan is currently undergoing clinical trials as the active constituent of a vaginal gel product for use as a female-controlled option to prevent the transmission of HIV during sexual intercourse. Here we show that in the presence of 0.5 mg/ml of carrageenan, human blood polymorphonuclear leukocytes (PMN) do not ingest this material, as evidenced by a lack of progressive vacuolization, but can ingest microorganisms present in the medium, excluding adjacent carrageenan. Moreover, PMN move at normal speeds, respond chemotactically, and reduce nitroblue tetrazolium (NBT) to formazan on stimulation. Hence, in the presence of carrageenan the phagocytic response appears to remain intact.

P032 Oxidative stress in red blood cells, platelets and polymorphonuclear leukocytes from patients with myelodysplastic syndrome

P032 Oxidative stress in red blood cells, platelets and polymorphonuclear leukocytes from patients with myelodysplastic syndrome

Frequent Occult Infection with Cytomegalovirus in Cardiac Transplant Recipients despite Antiviral Prophylaxis

Despite antiviral prophylaxis, a high percentage (over 90%) of heart transplant patients experience active cytomegalovirus (CMV) infection, diagnosed by detection of viral DNA in peripheral blood polymorphonuclear leukocytes within the first few months posttransplantation. Viral DNA was detected in mononuclear cells prior to detection in granulocytes from CMV-seropositive recipients (R+) receiving a heart from a CMV-seropositive donor (D+). Based on assessment of systemic infection in leukocyte populations, both R+ subgroups (R+/D- and R+/D+) experienced a greater infection burden than the R-/D+ subgroup, which was aggressively treated because of a higher risk of acute CMV disease. Despite widespread systemic infection in all at-risk patient subgroups, CMV DNA was rarely (< 3% of patients) detected in transplanted heart biopsy specimens. The R+ patients more frequently exceeded the 75th percentile of the CMV DNA copy number distribution in leukocytes (110 copies/10(5) polymorphonuclear leukocytes) than the R-/D+ subgroup. Therefore, active systemic CMV infection involving leukocytes is common in heart transplant recipients receiving prophylaxis to reduce acute disease. Infection of the transplanted organ is rare, suggesting that chronic vascular disease attributed to CMV may be driven by the consequences of systemic infection.

Biosynthesis of eicosanoids and transcellular metabolism of leukotrienes in murine bone marrow cells

Leukotriene B(4) (LTB(4)) biosynthesis by polymorphonuclear leukocytes (PMNs) is an important factor of inflammatory responses. PMNs also release LTA(4), an unstable intermediate that can be taken up by neighboring cells and metabolized into LTC(4). Most studies of LT synthesis have been carried out using human PMNs, but very little information is available about mouse PMNs. Mouse bone marrow PMNs were found to synthesize eicosanoids upon stimulation with A23187, fMLP, or zymosan. The major eicosanoids produced are LTB(4) and 5-hydroxyeicosatetraenoic acid, with some nonenzymatic products of LTA(4) hydrolysis. No cysteinyl leukotrienes were produced, in contrast to what was observed with human blood neutrophil preparations. Human megakaryoblast-like MEG-01 cells synthesized thromboxane B(2) and prostaglandin E(2) in response to A23187 but produced no 5-lipoxygenase (5-LO)-derived eicosanoids. When mouse bone marrow cells (mBMCs) and MEG-01 cells were stimulated during coincubation, LTC(4) and LTD(4) were produced. Mouse peritoneal macrophages from 5-LO-deficient mice were able to synthesize LTC(4) when incubated with mBMCs from wild-type mice, demonstrating transcellular exchange of LTA(4) from mBMCs into murine peritoneal macrophages. These data demonstrate that murine bone marrow PMNs are a valid model for the study of LT biosynthesis, which now offers the possibility to investigate specific biochemical pathways through the use of transgenic mice.

Cyclosporin-A Augments Respiratory Burst of Whole Blood Phagocytes in Pregnant Rats

Both pregnancy and cyclosporin A (CsA) are known to inhibit T-cell mediated immune response and to activate phagocytes against microbial infections as a compensatory mechanism. Pregnant women, either with organ transplantation or suffering from autoimmune diseases, are commonly managed with CsA therapy. This investigation was aimed to study effect of CsA on phagocytic activity of whole blood polymorphonuclear leukocytes (PMNs) in pregnant rats. Both pregnant and non-pregnant Sprague–Dawley rats (4 animals per group) were treated with CsA (40 mg/kg, oral) for 7 days starting from gestation day 7. Respective control groups of non-pregnant and pregnant rats received vehicle only. Luminol-dependent chemiluminescence (CL) was used to measure the generation of reactive oxygen species (ROS) in respiratory burst of whole blood PMNs stimulated by zymosan. The results showed a moderate and insignificant increase in CL response in non-pregnant rats with CsA treatment or pregnant rats without CsA treatment. Whereas the CL response of whole blood PMNs was significantly higher (ANOVA F = 35.66, P < 0.001) in pregnant rats treated with CsA. In conclusion, this preliminary study demonstrates synergistic effects of pregnancy and CsA on activation of PMNs resulting in massive and sustained generation of ROS that could be deleterious to both host and fetus.

Oxidative Stress in Red Blood Cells, Platelets and Polymorphonuclear Leukocytes from Patients with Myelodysplastic Syndrome.

Myelodysplastic syndrome (MDS) is characterized by refractory cytopenias due to ineffective hematopoiesis. Some patients with severe anemia require multiple blood transfusions and develop iron overload. Consequently, reactive oxygen species (ROS) are generated concomitant with a decrease in cellular antioxidants such as reduced gluthatione (GSH). The generated oxidative stress contributes to cell damage, apoptosis and ineffective hematopoiesis.Using flow cytometry, we measured the oxidative state of RBC, platelets and PMN in 14 low-risk MDS patients and 25 normal donors. The results indicate that the majority of the patients had higher ROS in RBC (2.79-fold) and platelets (2.91-fold) and lower GSH in their RBC (3.4-fold) and platelets (2.1-fold) than normal (p<0.005). As for PMN, there were no significant differences in ROS, although GSH was significantly (p<0.1) lower in MDS compared with normal donors. The oxidative stress in MDS cells could be ameliorated by a short in vitro treatment with the iron-chelators deferrioxamine and deferiprone, or with the anti-oxidant N-acetylcysteine. These results suggest that the decrease in transfusion requirements with increase in platelet and PMN counts in MDS patients treated with deferrioxamine may be due to indirect antioxidant effect of the iron chelator and suggest that treatment with a combination of iron-chelators and anti-oxidants might be more effective. [Display omitted] [Display omitted]

The apoptosis of blood polymorphonuclear leukocytes in sickle cell disease

The apoptosis of human polymorphonuclear leukocytes (PMNs) in patients with sickle cell disease (SCD) is not well understood. The goal of this study was to examine the apoptosis of PMNs in patients with SCD and in controls. Flow cytometric quantitation of PMN apoptosis was performed in 17 patients during and after sickle cell vasoocclusive crisis and in 17 healthy volunteers. Plasma nitric oxide concentrations were also measured in patients with SCD. The mean of annexin-V and annexin-V/PI staining (early and late apoptotic cells) increased to a greater degree in patients with SCD than in healthy controls for patients with SCD during and after vasoocclusive crisis. The mean of PI staining showing dead cells was higher only in patients after SCD crisis than in healthy controls. In the SCD groups during and after vasoocclusive crisis, there was no difference between PMN apoptosis levels. Furthermore, plasma nitric oxide concentrations were not correlated with PMN apoptosis. There was an evidence that the alteration of blood PMN apoptosis could contribute to the pathogenetic mechanisms of vasoocclusion in patients with SCD. This can be attributed to the effects of numerous inflammatory mediators rather than simply the effects of nitric oxide.

Nuclear factor-kappaB expression in peripheral blood polymorphonuclear leukocytes of patients with acute pancreatitis and the preventive effectiveness of pyrrolidine dithiocarbamate on NF-kappaB in vitro

To investigate the expression of NF-kappaB in peripheral blood polymorphonuclear leukocyte (PMN) of acute pancreatitis (AP) and to assess the preventive effectiveness of pyrrolidine dithiocarbamate (PDTC) on NF-kappaB in vitro. Nineteen patients and 16 healthy individuals as control were enrolled in this study. The expression of NF-kappaB in PMNs was determined by gel electrophoretic mobility shift assay (EMSA). Routine clinical examination results and computed tomography findings of AP were recorded in all patients. The PMNs from the patients with AP showed higher levels of NF-kappaB activities than those from control subjects (P < 0.01), severe acute pancreatitis (SAP) group showed much higher than mild acute pancreatitis (MAP) group (P < 0.05). In vitro, PDTC could reduce the NF-kappaB activity in PMNs of patients with AP, and its effectiveness at 2 mmol/L was stronger than at 1 mmol/L (P < 0.05). The PMNs from control subjects pretreated with 2 mmol/L PDTC before stimulation with the plasma from patients with SAP showed lower levels of NF-kappaB activities than did those untreated (P < 0.05). The NF-kappaB activation in peripheral blood PMNs participate in the course of acute pancreatitis and can be inhibited by PDTC in vitro.

Influence of purified saponin mixture from Astragalus corniculatus Bieb. on phagocytic cells in Graffi-tumor bearing hamsters

A purified saponin mixture (PSM) from Astragalus corniculatus Bieb. protected significantly hamsters against the experimental Graffi myeloid tumor. The application of PSM increased the survival rates, prolonged mean survival time and the tumor growth was markedly reduced. A purified saponin mixture (PSM) of Astragalus corniculatus Bieb. was evaluated for its immunostimulating potentials on the phagocytic cells in Graffi-tumor bearing hamsters. The number, migration and phagocytic indexes of peritoneal macrophages (pMøs) and of blood polymorphonuclear leukocytes (PMNs) were evaluated in healthy and Graffi-tumor bearing hamsters (G-TBH) treated with PSM. It was established that the Graffi myeloid tumor induced suppression of the phagocytic abilities of pMøs and PMNs. The number and migration of pMøs was significantly decreased during the whole period of observation. All tested parameters—number, migration and phagocytic activities of pMøs, as well as phagocytic ability of PMNs increased significantly in healthy and G-TBH after i.p. application of the 50 mg/kg body weight PSM. The PMS extracts from Astragalus corniculatus Bieb. are isolated and examined and their immunostimulating and immunorestorating impact on phagocitic cells was proven for the first time. This effect could be due to their high content of purified saponins.

Acute Rejection and Cardiac Allograft Vascular Disease Is Reduced by Suppression of Subclinical Cytomegalovirus Infection

Anticytomegalovirus (CMV) prophylaxis prevents the acute disease but its impact on subclinical infection and allograft outcome is unknown. We sought to determine whether CMV prophylaxis administered for three months after heart transplant would improve patient outcomes. This prospective cohort study of 66 heart transplant recipients compared aggressive CMV prophylaxis (n = 21, CMV hyperimmune globulin [CMVIG] plus four weeks of intravenous ganciclovir followed by two months of valganciclovir); with standard prophylaxis (n = 45, intravenous ganciclovir for four weeks). Prophylaxis was based on pretransplant donor (D) and recipient (R) CMV serology: R-/D+ received aggressive prophylaxis; R+ received standard prophylaxis. Outcome measures were: CMV infection assessed by DNA-polymerase chain reaction on peripheral blood polymorphonuclear leukocytes, acute rejection, and cardiac allograft vascular disease (CAV) assessed by intravascular ultrasound. All patients completed one year of follow-up. RESULTS.: CMV infection was subclinical in all but four patients (two in each group). Aggressively treated patients had a lower incidence of CMV infection (73 +/- 10% vs. 94 +/- 4%; P = 0.038), and an independent reduced relative risk for acute rejection graded > or =3A (relative risk [95% CI] = 0.55 [0.26-0.96]; P = 0.03), as compared with the standard prophylaxis group. Aggressively prophylaxed patients also showed a slower progression of CAV, in terms of coronary artery lumen loss (lumen volume change=-21 +/- 13% vs. -10+/-14%; P = 0.05); and vessel shrinkage (vessel volume change = -15 +/- 11% vs. -3 +/- 18%; P = 0.03). Prolonged (val)ganciclovir plus CMVIG reduces viral levels, acute rejection, and allograft vascular disease, suggesting a role for chronic subclinical infection in the pathophysiology of the most common diseases affecting heart transplant recipients.

Antiplatelet and Antileukocyte Effects of Cardiovascular,Immunomodulatory and Chemotherapeutic Drugs

In vitro and ex vivo interactions of betaadrenoceptor blocking drugs, antihistamines and chloroquine with blood platelets and polymorphonuclear leukocytes resulted in different alterations of regulatory functions of these blood cells. Inhibition of platelet aggregation, arachidonate regulatory pathway, 5-hydroxytryptamine transportation, removal of platelet membrane receptors, inhibition of second messenger pathways at subcellular level and suppression of phagocytosis are indicative of nonreceptor rather than specific receptor interactions. Binding of drugs with biomembranes is reversible depending on the ionic charge of the molecule and hydrophobicity of the bilayer, partition coefficient, pH and pKa of the amphiphilic molecules and other physico-chemical properties of amphiphilic drugs. Alterations in the drug molecule structure alters the drug-phospholipid binding profile. Any change in the metabolism of membrane phospholipids directly or indirectly influences one or more of the important components of the phospholipid-signalling pathway. In addition to changes in phospholipase A, C and D activities, protein kinase C, calmodulin-phosphodiesterase, Ca2+,Mg2+-ATPase, Na+,K+-ATPase and other messengers were found to be changed in cells and tissue after cationic amphiphilic drug (CAD) administration. Although not much has been understood of the mechanism by which some CAD affect immune functions, there are good reasons to suggest that these effects might occur. CADs share sufficient similarities in their structure even though they come from diverse pharmacological classes. CADs affect ion transport, immune functions, tumour growth, serotonin metabolism and several other functions in the body. Extensive therapeutic use and associated side effects have generated a great deal of interest in understanding the nonreceptor interactions with CADs.

Activation state-dependent interaction between Galphai and p67phox.

The phagocyte NADPH oxidase consists of multiple protein subunits that interact with each other to form a functional superoxide-generating complex. Although the essential components for superoxide production have been well characterized, other proteins potentially involved in the regulation of NADPH oxidase activation remain to be identified. We report here that the Galphai subunit of heterotrimeric G proteins is a novel binding partner for p67phox in transfected HEK293T cells and peripheral blood polymorphonuclear leukocytes. p67phox preferably interacted with inactive Galphai. Expression of p67phox caused a dose-dependent decrease in intracellular cyclic AMP concentration, suggesting altered function of Galphai. We identified a fragment of p67phox, consisting of the PB1 domain and the C-terminal SH3 domain, to be critical for the interaction with Galphai. Because these domains are involved in the interaction with p47phox and p40phox, the relationship between the respective binding events was investigated. Wild-type Galphai, but not its QL mutant, could promote the interaction between p67phox and p47phox. However, the interaction between p67phox and p40phox was not affected by either Galphai form. These results provide the first evidence for an interaction between p67phox and an alpha subunit of heterotrimeric G proteins, suggesting a potential role for Galphai in the regulation or activation of NADPH oxidase.

Effect of cyclosporin A on human neutrophil and monocyte function.

The effect of various concentrations of cyclosporin A (CyA), ranging from below peak blood levels to 20 times higher than blood levels of human peripheral blood polymorphonuclear and mononuclear leukocytes, was examined. CyA was found to bind to neutrophils with Kd values in the range of 20-50 nM. CyA at clinically obtainable blood level concentrations had no effect on neutrophil and monocyte chemotaxis, neutrophil oxidative burst, monocyte phagocytosis, or neutrophil bactericidal activity. The data on the release of lactoferrin, a secondary granule substance, from activated neutrophils showed that the calcium ionophore A 23187-induced lactoferrin release was inhibited by treatment of cells with 4 microM CyA, whereas release of lactoferrin from zymosan- or phorbol myristate acetate-activated neutrophils was not affected by the same concentration of CyA. This effect could either be due to differences in the degree of cell membrane perturbation by the various activators or to calcium dependence of neutrophil activation. A third possibility may be that CyA acts at some subsequent steps in the release process of neutrophils. It is concluded that CyA does not interfere with important functions of human phagocytes, the cells that play a major role in the defence against invading microorganisms.

Regulation of leukocyte adhesion molecules by leukocyte/biomaterial‐conditioned media: A study with calcium‐phosphate‐coated and non‐coated NiTi‐shape memory alloys

AbstractTo evaluate the role of soluble mediators released after interaction of leukocytes with biomaterials on cells of the implant microenvironment, the surface expression of adhesion molecules (CD11b, CD62L, CD66b, ICAM‐1) on freshly isolated whole blood leukocytes (WBL) was analyzed by flow cytometry after incubation in leukocyte/nickel‐titanium shape‐memory alloy (NiTi‐SMA)‐conditioned media. NiTi‐SMA samples were either coated with calcium phosphate by dipping in oversaturated calcium phosphate solution (CaP‐coating) or were non‐coated. Peripheral blood mononuclear cells (PBMC) and polymorphonuclear neutrophil leukocytes (PMN) were isolated and seeded on both samples to generate respective conditioned media. In comparison with conditioned media obtained by non‐coated NiTi‐SMA, the expression of CD11b, CD66b, and ICAM‐1 on WBL was upregulated by conditioned media obtained from CaP‐coated samples. In contrast, the expression of CD62L on WBL was decreased after incubation in conditioned medium obtained from CaP‐coated NiTi‐samples compared to non‐coated NiTi. These data demonstrate the possible influence of released mediators elicited by leukocyte‐biomaterial interactions on cells of the implant microenvironment.

Relationship between polymorphonuclear leucocytes and the outcome of patients with severe trauma

Major trauma is accompanied by a marked inflammatory reaction that involves infiltration of blood polymorphonuclear leucocytes (PMNs) into the injured area. This process is dynamic and evolves rapidly over the first 24–72 hours after injury. Activated PMNs can contribute to tissue damage by release of oxygen radicals, proteolytic enzymes and proinflammatory cytokines. The acute respiratory distress syndrome (ARDS) that occurs early after major trauma is characterized by a neutrophil infiltrate within the lungs. Also the inflammation, in response to brain injury, involves infiltration of neutrophils into the injured brain parenchyma.