An enzyme-linked immunosorbent assay for plasma-lactoferrin. Concentrations in 362 healthy, adult blood donors

Neutrophil count as the centerpiece in the joined association networks of inflammatory and cell damage markers, and neuroendocrine stress markers in patients with stable angina pectoris following stenting

Objective

The primary aim of this study was to examine whether markers of cell damage and of the psycho-neuroendocrino-inflammatory/immune (PNI) system could be associated in patients with stable coronary artery disease (CAD) on the next day following percutaneous coronary intervention (PCI).

Materials and methods

Blood samples of 23 patients (18 men and five women, mean age 62.9 ± 10.6 years), were collected immediately before (pre-PCI), immediately after (post-PCI), and on the day following PCI (1d-PCI). Lactoferrin, LL-37 and interleukin-6 (IL-6) were assayed in plasma, in addition to cortisol and chromogranin A (CgA), as well as CK, ASAT and ALAT. Total and differential leukocyte counts were also analysed.

Results

At all the three time points, the monocyte fractions, the monocyte-to-lymphocyte and the neutrophil-to-lymphocyte ratios and CgA levels were elevated. We detected significant peri-procedural changes in the plasma levels of our PNI markers: IL-6 (p<0.05), lactoferrin, LL-37 (both: p <0.0001), CgA, (p<0.05), and cortisol (p<0.01). On the first day after PCI, highly significant associations were found of ASAT with IL-6 and neutrophil count (both: r>0.75, p<0.0001), and of CgA with neutrophil count and monocyte count (both: r>0.79, p<0.0001); furthermore, cortisol was also associated with neutrophil count (r>0.7, p<0.0001).

Conclusions

The findings suggest that myocardial damage could correlate not only with an inflammatory reaction but, via neutrophil count, also with increased level of stress in stable CAD after PCI. Furthermore, 1d-PCI neutrophil count may serve as an easy-to-obtain integrative PNI measure in stable CAD.

Vascular Localization of the Heparin-binding Serpins Antithrombin, Heparin Cofactor II, and Protein C Inhibitor

Heparin is one of the most widely used drugs in the world, acting as an anticoagulant by stimulating the reaction between heparin-binding serpins and the serine proteases of the coagulation cascade. To determine whether the heparin-binding serpins antithrombin (AT), heparin cofactor II (HCII), and protein C inhibitor (PCI) were bound to glycosaminoglycans on the endothelial wall, a bolus of heparin (100 U/kg body weight) was in jected into human volunteers, and serpin concentrations and activities were measured in both pre- and postheparin plasma. No increase in circulating concentrations of AT, HCII, or PCI were observed in postheparin plasma. Sim ilarly, AT and HCII activities did not increase in posthe parin plasma. In contrast, the concentration of another heparin-binding protein, lactoferrin (LF), increased six- fold after heparin injection. Immunohistochemistry of hu man artery was performed using polyclonal antisera to AT, HCII, PCI, LF, and tissue factor pathway inhibitor (TFPI), another heparin-binding protein released by hep arin injection. AT, HCII, and PCI were present in the intima, whereas LF, TFPI, and traces of AT were found on the surface of the vessel wall. The distribution of the proteins in the vessel wall supports the results of the hep arin-injection studies and may give valuable clues to the role of each protein in vascular homeostasis.

ACTH- and cortisol-associated neutrophil modulation in coronary artery disease patients undergoing stent implantation

Background

Psychosocial stress and activation of neutrophil granulocytes are increasingly recognized as major risk factors of coronary artery disease (CAD), but the possible relationship of these two factors in CAD patients is largely unexplored. Activation of neutrophils was reported to be associated with stenting; however, the issue of neutrophil state in connection with percutaneous coronary intervention (PCI) is incompletely understood from the aspect of stress and its hypothalamic-pituitary-adrenal axis (HPA) background. Thus, we aimed to study cortisol- and ACTH-associated changes in granulocyte activation in patients undergoing PCI.

Methodology/Principal Findings

Blood samples of 21 stable angina pectoris (SAP) and 20 acute coronary syndrome (ACS) patients were collected directly before (pre-PCI), after (post-PCI) and on the following day of PCI (1d-PCI). Granulocyte surface L-selectin, CD15 and (neutrophil-specific) lactoferrin were analysed by flow cytometry. Plasma cortisol, ACTH, and lactoferrin, IL-6 were also assayed. In both groups, pre- and post-PCI ratios of lactoferrin-bearing neutrophils were relatively high, these percentages decreased substantially next day; similarly, 1d-PCI plasma lactoferrin was about half of the post-PCI value (all p≤0.0001). Post-PCI ACTH was reduced markedly next day, especially in ACS group (SAP: p<0.01, ACS: p≤0.0001). In ACS, elevated pre-PCI cortisol decreased considerably a day after stenting (p<0.01); in pre-PCI samples, cortisol correlated with plasma lactoferrin (r∼0.5, p<0.05). In 1d-PCI samples of both groups, ACTH showed negative associations with the ratio of lactoferrin-bearing neutrophils (SAP: r = −0.601, p<0.005; ACS: r = −0.541, p<0.05) and with plasma lactoferrin (SAP: r = −0.435, p<0.05; ACS: r = −0.609, p<0.005).

Conclusions/Significance

Pre- and post-PCI states were associated with increased percentage of activated/degranulated neutrophils indicated by elevated lactoferrin parameters, the 1d-PCI declines of which were associated with plasma ACTH in both groups. The correlation of plasma cortisol with plasma lactoferrin in the extremely stressed ACS before stenting, however, suggests an association of cortisol with neutrophil activation.

Salivary anticandidal activity and saliva composition in an HIV-infected cohort

This study investigated salivary anticandidal activity and salivary composition in stimulated whole saliva of 18 advanced HIV-infected patients and compared these values to healthy controls. Stimulated whole saliva from HIV-infected patients showed decreased anticandidal activity. The flow rate was reduced by 40% as compared with controls. The saliva flow rate for HIV-infected patients who had recoverable yeast in their saliva was reduced as compared to HIV-infected patients without recoverable yeast. For HIV-infected patients, the saliva concentrations of lactoferrin, secretory IgA and Cl- were increased while the secretion rate of lysozyme, total protein and K+ were reduced. There was no difference in any parameter as a function of taking the antifungal drug fluconazole. There was no association between salivary anticandidal activity and any salivary component. This study shows reduced anticandidal activity and salivary flow rate in HIV-infected patients. These alterations may contribute to their increased incidence of oral candidal infections.

Ribonuclease, cell-free translation-inhibitory and superoxide radical scavenging activities of the iron-binding protein lactoferrin from bovine milk

The purpose of this study was to characterize the ribonuclease (RNase) and cell-free translation-inhibitory activities of lactoferrin isolated from bovine milk. It was found that bovine lactoferrin exhibited ribonucleolytic activity toward yeast transfer RNA in a dose-dependent manner. The pH optimum for this RNase activity was in the vicinity of 7.5. Lactoferrin exerted RNase activity on poly C with an activity of 2.15 U/mg. No activity was detected toward poly A, poly G, and poly U. The milk protein inhibited cell-free translation in rabbit reticulocyte lysate with an IC50 of 9.6 microM. The protein was devoid of N-glycosidase activity characteristic of ribosome inactivating proteins which also possess RNase and cell-free translation-inhibitory activities. It inhibited superoxide radical formation.

Plasma lactoferrin levels are decreased in end-stage AIDS patients

The antimicrobial protein lactoferrin (Lf) is present in plasma and in mucosal secretions. Using ELISA we analysed plasma and saliva of HIV-infected patients, patients with AIDS, and healthy controls for the presence of secreted Lf. The plasma Lf levels of AIDS patients (classification C3) were significantly lower (p < 0.001) as compared to asymptomatic and symptomatic HIV infected patients, or controls. In addition, plasma Lf levels closely correlated with neutrophilic granulocyte counts in the HIV-infected patients. Thus, basal plasma Lf levels are likely the result of Lf release by neutrophilic granulocytes. The Candida titres present in the oral cavity were determined in a part of the HIV-infected patient group. As it appeared, the presence of this opportunistic pathogen always coincided with low levels of salivary Lf levels. We conclude that Lf, as part of the nonspecific immune system, might play an important role in the first line of defense against opportunistic microbial infections in AIDS patients.

Metal storage and transport proteins increase after exposure of the rat lung to an air pollution particle

With the single exception of mercury, all metals in the atmosphere are associated with particles. The lungs are subsequently exposed to metals present in air pollution particles on a continuous basis. Because metal exposure can be associated with an oxidative stress, a mechanism that isolates the metal in a chemically less reactive form would be of benefit. We tested the hypothesis that the concentrations of both lactoferrin and ferritin in the rat lung increase after exposure to a metal-rich emission source air pollution particle. Using immunohistochemistry, we characterized changes in the concentrations of ferritin and lactoferrin after exposure of rats to an emission source air pollution particle. Lavage metal concentrations, measured by inductively coupled plasma emission spectroscopy, increased 4 hr after exposure to an oil fly ash. After exposure to this metal-rich emission source air pollution particle, ferritin concentrations in the lower respiratory tract increased. Comparable to the iron-storage protein, concentrations of both lactoferrin and transferrin were elevated after exposure. The greatest concentrations of ferritin, lactoferrin, and transferrin occurred at approximately 24 hr after exposure to the air pollution particle. Levels then decreased, and by 96 hr after instillation of the oil fly ash, ferritin, lactoferrin, and transferrin were not elevated relative to those animals exposed to saline. We conclude that, in response to an emission source air pollution particle with high concentrations of metals, there is an increase in ferritin, lactoferrin, and transferrin concentrations in the lungs of the host. The function of these increases in iron-binding proteins may be to control the oxidative stress associated with the exposure to metals.

Reduced expression of C5a receptors on neutrophils from cord blood

AIM

To describe further functional deficiencies of neonatal neutrophils by measuring the expression of C5a receptors.

METHODS

C5a uptake was measured using flow cytometry with fluorescein isothiocynate labelled recombinant C5a. The response of neutrophils to stimulation with C5a and fMLP was tested by measuring migration and exocytosis of myeloperoxidase and lactoferrin.

RESULTS

C5a mean fluorescence on neutrophils from neonates was significantly lower (22.4 (SD 3.5)) than in adult controls (31.5 (3.1)). Neutrophils from neonates migrated poorly towards both C5a and fMLP compared with those from adult controls. Exocytosis of myeloperoxidase, but not lactoferrin from neonatal neutrophils stimulated with C5a, was significantly lower than in adult controls. fMLP stimulation, on the other hand, resulted in significantly higher exocytosis in neonates.

CONCLUSION

The lower expression of C5a receptors on neutrophils from neonates could be related to reduced C5a mediated exocytosis of myeloperoxidase.

Gingival crevicular neutrophils: membrane molecules do not distinguish between periodontitis and gingivitis

We have earlier reported hyperreactive peripheral neutrophils in adult periodontitis, measured as respiratory burst after Fc gamma receptor-mediated activation in vitro, but we have not been able to relate this increased activity to aberrations in the expression of relevant membrane molecules. Various types of inflammatory conditions involving the gingiva should affect membranes differently. We therefore collected crevicular neutrophils from three types of inflammatory sites: (i) with and (ii) without tissue destruction in the same periodontitis patients and (iii) inflamed sites in controls with gingivitis alone and compared the expression of membrane molecules by flow cytometry. The % of positively stained cells and their mean intensities of fluorescence (IFL) were similar in the three types of sites for CD15, CD11a, CD11b and CD16. Peripheral neutrophils studied with the same markers were not activated. This was verified by similar plasma concentrations of lactoferrin and L-selectins in the periodontal and control groups. Compared to peripheral cells, the crevicular neutrophils showed a significantly lower percentage of stained cells, while the stained cells increased their IFL. In conclusion, hyperreactive peripheral neutrophils in periodontitis show the same expression of membrane molecules after migration through different types of inflammatory lesions as do normal neutrophils in gingivitis.

The roles of complement receptors type 1 (CR1, CD35) and type 3 (CR3, CD11b/CD18) in the regulation of the immune complex-elicited respiratory burst of polymorphonuclear leukocytes in whole blood

The binding of immune complexes (IC) to polymorphonuclear leukocytes (PMN) and the consequent respiratory burst (RB) were investigated in whole blood cell preparations suspended in 75% human serum, using flow cytometry. Blockade of the complement receptor (CR)1 receptor sites for C3b on whole blood cells using the monoclonal antibody (mAb) 3D9 resulted in a 1.9-fold increase in the IC-elicited PMN RB after 5 min of incubation, rising to 3.1-fold after 40 min. This enhancement was not due to increased IC deposition on PMN. Blockade of CR3 abrogated the mAb 3D9-induced rise in RB activity and inhibited the IC binding to PMN in a whole blood cell preparation, with or without mAb 3D9, by approximately 40% from 15-40 min while reducing their RB over 40 min to approximately one third. Blockade of CR1 on either erythrocytes (E) or leukocytes, before mixing the populations, revealed that the potentiation of the RB by mAb 3D9 was associated with abrogation of E-CR1 function, whereas blockade of leukocyte-CR1 had a diminishing effect. Exposure to IC at high concentrations induced release of both specific and azurophilic granule contents from PMN. The latter was CR3 dependent in that blockade of the receptor inhibited the lactoferrin release by one third during 40 min of incubation. In conclusion, CR3 plays a significant role in the IC-mediated generation of an RB and release of specific granules by PMN, while CR1 on whole blood cells, primarily E CR1, restricts the IC-elicited RB in PMN. We propose that CR1 in whole blood promotes the degradation of IC-bound iC3b to C3dg, thereby rendering the IC inaccessible for binding to CR3.

Oxidative-stress associated parameters (lactoferrin, superoxide dismutases) in serum of patients with Alzheimer's disease

In this case/control study, serum levels of oxidative stress related parameters such as Fe-binding lactoferrin (LTF), Mn- and Zn,Cu-superoxide dismutase (SOD) were determined by enzyme linked immunoassays in patients suffering from the Alzheimer's dementia as well as in non-demented controls. The Mn-SOD concentration was significantly (P<0.05, U-test) reduced in patients suffering from Alzheimer's disease if compared to non-demented controls. The other parameters investigated did not differ significantly between both groups. Our findings give evidence for the hypothesis of a disturbed free radical metabolism in Alzheimer's disease. The specificity of these results remains to be clarified. Further studies are needed to elucidate the relevance of oxidative stress in the etiopathogenesis of the Alzheimer's disease.

Diagnostic value of blood cytokine concentrations in acute pneumonia

BACKGROUND

The role of cytokines in the pathogenesis of pneumonia is still poorly understood. In a previous study the diagnostic value of measuring blood concentrations of interleukin 6 and interferon gamma was established. In the present study the value of blood concentrations of interleukin 8, granulocyte-colony stimulating factor, and lactoferrin as markers of bacteraemic pneumonia is evaluated.

METHODS

The circulating concentrations of interleukin 8 (IL-8), granulocyte-colony stimulating factor (G-CSF), and lactoferrin were measured in 14 patients with bacteraemic pneumococcal pneumonia and 49 patients with atypical pneumonia or influenza A infection using enzyme immunoassays.

RESULTS

Serum G-CSF concentrations were higher in the group with bacteraemic pneumococcal pneumonia, and G-CSF values correlated with the white blood cell count and levels of C-reactive protein (CRP). The levels of IL-8 were higher in the group with bacteraemic pneumococcal pneumonia than the groups with Chlamydia pneumonia, Legionella pneumonia, or influenza A infection, but there was no difference when compared with the group with Mycoplasma pneumonia. A white blood cell count of > 15 x 10(9)/l was highly suggestive of bacteraemic pneumonia. The concentrations of lactoferrin were raised in all groups except those with influenza A infection, but no difference was found between the different aetiological groups. A correlation was found between lactoferrin and white blood cell counts.

CONCLUSIONS

Serum G-CSF and IL-8 concentrations are potential markers of bacteraemic pneumonia.

Interleukin-6, C-reactive protein, lactoferrin and white blood cell count in patients with S. aureus septicemia

In a prospective study of 65 patients with S. aureus septicemia, the clinical value of measuring serum IL-6 and lactoferrin levels was assessed and compared with CRP levels and WBC count. 20/65 (31%) patients had a CRP value < or = 100 mg/l on admission and 10 (50%) and 11 (55%) of these had serum levels of IL-6 > 100 pg/ml or lactoferrin > 2.0 mg/l, respectively. 41/64 (64%) patients had a WBC count < or = 15.0 x 10(9)/l and the corresponding figures for increased IL-6 and lactoferrin values were 29 (71%) and 21 (51%) patients, respectively. The high concentrations of IL-6 and lactoferrin on admission decreased rapidly during the hospital stay, better reflecting the clinical course than CRP and WBC count. Patients with endocarditis showed higher IL-6 levels and body temperatures both on admission and during the first days of hospitalization compared with patients without endocarditis.

Aspects of preanalytical variation of lactoferrin and elastase/alpha 1-protease inhibitor complexes

A number of interesting applications of plasma elastase/alpha 1-protease inhibitor complexes (ELA-PI) and lactoferrin (LAC) have recently been suggested. However, the clinical utility of these components often seems to be low. This might be improved by minimizing the preanalytical variation, if possible. Therefore, we have evaluated the influence of various aspects of sampling and handling conditions on the results obtained when measuring ELA-PI and LAC. Blood samples from both healthy persons as well as patients, who had undergone laparotomy the day before, were investigated. We confirmed the previous observations of higher concentrations of ELA-PI and LAC in serum compared to plasma. This was more pronounced in patients than in healthy adults. In EDTA-blood the most important change was seen in samples from patients when stored at room temperature. In this situation increases of LAC concentrations of 50% and 100% following 2 and 5 h, respectively were found. This in vitro release of LAC was abolished when samples were stored on ice until centrifugation within 5 h. In contrast, a statistically significant increase in ELA-PI of 10% was observed following storage on ice for 2 h of blood specimens drawn from healthy persons. EDTA-plasma obtained by venous puncture following minimal stasis contained 10% higher concentrations of LAC compared to samples drawn from intravenous catheters, while no difference was observed in the case of ELA-PI. However, in one individual prolonged venous stasis resulted in larger differences of both LAC and ELA-PI. Different centrifugation conditions (1500 vs. 3000 x g; room temperature vs. 4 degrees C) did not influence concentrations of LAC or ELA-PI measured, neither did eating a normal meal nor moderate physical activity (30 min walk). In conclusion, ELA-PI and LAC should be measured in EDTA-plasma. Blood must be drawn by venous puncture applying minimal stasis or from indwelling venous catheters. Samples for measuring LAC must be stored on ice until centrifugation. Separation of plasma from cells should be performed as fast as possible, but storage for up to 5 h can be accepted.