Prevention of activated neutrophil adhesion to endothelium by soluble adhesion protein GMP140

Potential Roles of Selectins in Periodontal Diseases and Associated Systemic Diseases: Could They Be Targets for Immunotherapy?

Periodontal diseases are predisposing factors to the development of many systemic disorders, which is often initiated via leukocyte infiltration and vascular inflammation. These diseases could significantly affect human health and quality of life. Hence, it is vital to explore effective therapies to prevent disease progression. Periodontitis, which is characterized by gingival bleeding, disruption of the gingival capillary's integrity, and irreversible destruction of the periodontal supporting bone, appears to be caused by overexpression of selectins in periodontal tissues. Selectins (P-, L-, and E-selectins) are vital members of adhesion molecules regulating inflammatory and immune responses. They are mainly located in platelets, leukocytes, and endothelial cells. Furthermore, selectins are involved in the immunopathogenesis of vascular inflammatory diseases, such as cardiovascular disease, diabetes, cancers, and so on, by mediating leukocyte recruitment, platelet activation, and alteration of endothelial barrier permeability. Therefore, selectins could be new immunotherapeutic targets for periodontal disorders and their associated systemic diseases since they play a crucial role in immune regulation and endothelium dysfunction. However, the research on selectins and their association with periodontal and systemic diseases remains limited. This review aims to discuss the critical roles of selectins in periodontitis and associated systemic disorders and highlights the potential of selectins as therapeutic targets.

The Dual Role of Platelets in the Cardiovascular Risk of Chronic Inflammation

Patients with chronic inflammatory diseases often exhibit cardiovascular risk. This risk is associated with the systemic inflammation that persists in these patients, causing a sustained endothelial activation. Different mechanisms have been considered responsible for this systemic inflammation, among which activated platelets have been regarded as a major player. However, in recent years, the role of platelets has become controversial. Not only can this subcellular component release pro- and anti-inflammatory mediators, but it can also bind to different subsets of circulating lymphocytes, monocytes and neutrophils modulating their function in either direction. How platelets exert this dual role is not yet fully understood.

Pharmaceutical Development and Safety Evaluation of a GMP-Grade Fucoidan for Molecular Diagnosis of Cardiovascular Diseases

The adhesion molecule P-selectin is present on the cell surface of both activated endothelium and activated platelets. The present study describes the pharmaceutical development, safety evaluation, and preclinical efficacy of a micro-dosed radiotracer. The macromolecular nanoscale assembly consisted of a natural compound made of a sulfated fucose-rich polysaccharides (fucoidan) and a radionuclide (technetium-99m) for the detection of P-selectin expression in cardiovascular diseases. After extraction and fractionation from brown seaweeds, the good manufacturing practice (GMP) production of a low molecular weight (LMW) fucoidan of 7 kDa was achieved and full physicochemical characterization was performed. The regulatory toxicology study in rats of the GMP batch of LMW fucoidan revealed no adverse effects up to 400 μg/kg (×500 higher than the expected human dose) and pseudoallergy was not seen as well. In a myocardial ischemia-reperfusion model in rats, the GMP-grade LMW fucoidan labeled with technetium-99m detected P-selectin upregulation in vivo. The present study supports the potential of using ^99mTc-fucoidan as an imaging agent to detect activated endothelium in humans.

Effects of Yak skin gelatin on platelet activation

Studies have shown that gelatin is not only a good hemostatic material, but also a food additive with potentially broad use. Yak skin gelatin is a new gelatin resource, but its oral coagulant effects have not been studied. Given the central role of platelets in hemostasis, in this study we examined the pharmacodynamical differences between different molecular Yak skin gelatins on platelet activation. The hemostatic effects of Yak skin gelatins with different molecular weight distributions were evaluated for bleeding time (BT), clotting time (CT), and platelet activity by measuring the contents of P-selectin, platelet membrane glycoprotein Ia/IIa (GP Ia/IIa), platelet membrane glycoprotein IIb/IIIa (GP IIb/IIIa), and platelet membrane glycoprotein IV (GP IV). Intragastric administration of Yak skin gelatin resulted in a significant reduction in CT and BT, and an increase in the contents of P-selectin, GP Ia/IIa, GP IIb/IIIa, and GP IV in all groups in comparison with the control group. The strongest activation of platelets by Yak skin gelatin was observed with size between 0.1 μm and 0.22 μm, and activation may have been in response to improving GP IIb/IIIa and GP IV levels. When measuring the levels of an established indicator of platelet activation, platelet activation-dependent granule membrane protein (CD62P), its promotion was observed for all molecular weight ranges of Yak skin gelatins. In brief, Yak skin gelatin has hemostatic effects, and Yak skin gelatin fractions between 0.1 μm and 0.22 μm are the primary effectors of hemostasis via promoting platelet membrane glycoprotein activities and strengthening platelet function.

Expression, Distribution, and Role of C-Type Lectin Receptors in the Human and Animal Middle Ear and Eustachian Tube: A Review

Otitis media (OM) is a group of inflammatory diseases of the middle ear (ME), regardless of cause or pathological mechanism. Among the molecular biological studies assessing the pathology of OM are investigations into the expression of C-type lectin receptors (CLR) in the ME and Eustachian tube (ET). To date, nine studies have evaluated CLR expression in the ME and ET. The expression of individual CLRs in mammalian ME and ET varies by species and model of OM. Assessments have shown that the patterns of CLR expression in the ME and ET vary; that CLR expression may vary by type of OM; and that the distribution and levels of expression of CLRs may depend on the presence or absence of inflammation, with variations even within the same species and same tissue. Infection of the ME and ET with various pathogens is a common cause of all types of OM, with host responses to pathogens mediated initially by the innate immune system. CLRs are important factors in the innate immune system because they act as both adhesion molecules and as pathogen recognition receptors. The expression of CLRs in OM tissues suggests that CLRs are associated with the pathogenesis of various types of OM.

Intraoperative Blood Salvage (IOBS) in Cardiac and Vascular Surgery

The extensive application of IOBS has permitted a great reduction in the use of homoglous transfusion which presently represents the largest field of application of autologous systems. In cardiac and vascular surgery, IOBS is particularly useful to the goal of preventing the transmission of viral disorders and other adverse effects related to homologous transfusions. The apparatuses for IOBS may also be used to perform hemodilution and sequestration of a desired amount of platelet rich plasma. The appropriate usage of drugs in perioperative period and the promotion of hemostasis with IOBS are important costituents for the correct transfusional management of the patient. The feasibility and safety of IOBS is known and in expert hands it is an optimal method for the transfusional treatment of surgical patients

Reduced platelet hyper-reactivity and platelet-leukocyte aggregation after periodontal therapy

Background

Platelets from untreated periodontitis patients are hyper-reactive and form more platelet-leukocyte complexes compared to cells from individuals without periodontitis. It is not known whether the improvement of the periodontal condition achievable by therapy has beneficial effects on the platelet function. We aimed to assess the effects of periodontal therapy on platelet reactivity.

Methods

Patients with periodontitis (n = 25) but unaffected by any other medical condition or medication were included and donated blood before and after periodontal therapy. Reactivity to ADP or oral bacteria was assessed by flow cytometric analysis of membrane markers (binding of PAC-1, P-selectin, CD63) and platelet-leukocyte complex formation. Reactivity values were expressed as ratio between the stimulated and unstimulated sample. Plasma levels of soluble (s) P-selectin were determined by enzyme-linked immunosorbent assay (ELISA).

Results

Binding of PAC-1, the expression of P-selectin and CD63 in response to the oral bacterium P. gingivalis were lower at recall (1.4 ± 1.1, 1.5 ± 1.2, and 1.0 ± 0.1) than at baseline (2.7 ± 4.1, P = 0.026, 6.0 ± 12.5, P = 0.045, and 2.7 ± 6.7, P = 0.042, respectively). Formation of platelet-leukocyte complexes in response to P. gingivalis was also reduced at recall compared to baseline (1.2 ± 0.7 vs. 11.4 ± 50.5, P = 0.045). sP-selectin levels were significantly increased post-therapy.

Conclusions

In periodontitis patients, the improvement of the periodontal condition is paralleled by a reduction in platelet hyper-reactivity. We suggest that periodontal therapy, as an intervention for improved oral health, can facilitate the management of thrombotic risk, and on the long term can contribute to the prevention of cardiovascular events in patients at risk.

Trial registration

Current Controlled Trials identifier ISRCTN36043780. Retrospectively registered 25 September 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s12959-016-0125-x) contains supplementary material, which is available to authorized users.

Endothelial Cell Adhesion Molecules and Cardiopulmonary Bypass

Endothelial cell activation and the cell surface expression of adhesion molecules are considered to be crucial steps in the systemic inflammatory response to cardiopulmonary bypass. Endothelial cell adhesion molecules mediate the process of leukocyte adhesion to the endothelium and their subsequent transmigration and degranulation in the subendothelial tissues. The levels of soluble endothelial adhesion molecules in plasma have been used to draw conclusions regarding the cell surface expression of these molecules; the limitations of such studies are discussed. Inhibition of cell adhesion molecules may prevent the inflammatory condition caused by cardiopulmonary bypass and reperfusion injury. Further studies are needed to define the role of endothelial cell adhesion molecules in this inflammatory response.

Activation of platelets upon contact with a vitamin E-coated/non-coated surface

The purpose of this study was to determine the effects of a vitamin E-coated surface on platelet activation, focusing on the interactions among the vitamin E-coated surface, platelets and leukocytes. Platelet-rich plasma (PRP) or PRP containing leukocytes (LPRP) was used. No difference was observed in platelet activation between PRP and LPRP for a vitamin E-coated membrane, meaning that platelet activation triggered by leukocytes was suppressed in plasma coming in contact with a vitamin E-coated membrane, while the membrane itself directly induced platelet activation. The antioxidant capacity of the vitamin E-coated membrane in contact with PRP or LPRP was partially reduced, but sufficient residual capacity remained. The in vitro experiments using an oxidized vitamin E-coated surface revealed that P-selectin expression and superoxide anion production in the platelets and platelet adhesion were induced by contact with the oxidized vitamin E-coated surface. We conclude that contact with a vitamin E-coated surface reduces platelet activation mediated by superoxide anions, probably by reducing superoxide anions, but during the process of the reduction, the vitamin E-coated surface itself becomes oxidized, which again causes platelet activation. The beneficial effects of a vitamin E-coated dialyzer in respect of platelet activation were counteracted by the formation of oxidized vitamin E.

Radiolabeled fucoidan as a p-selectin targeting agent for in vivo imaging of platelet-rich thrombus and endothelial activation

P-selectin expression is involved in the pathophysiology of biologically active arterial thrombus and endothelial activation after a transient ischemic event. Fucoidan is a polysaccharidic ligand of P-selectin, with a nanomolar affinity. In the present study, we propose a new approach of P-selectin molecular imaging based on radiolabeled fucoidan.

METHODS

Two kinds of experimental models were selected to evaluate the ability of radiolabeled fucoidan to detect P-selectin expression: platelet-rich arterial thrombi (vegetations of infective endocarditis and arterial mural thrombus) and myocardial ischemia-reperfusion. These 2 settings were chosen because they were clinically relevant, and both were associated with an important overexpression of platelet and endothelial P-selectin, respectively.

RESULTS

(99m)Tc-fucoidan SPECT was able to detect the presence of platelet-rich arterial thrombi in all animals, with a median target-to-background ratio of 5.2 in vegetations of endocarditis and 3.6 in mural aneurysmal thrombus, and to detect a persistent endothelial activation at 2 h after reperfusion. In this latter model, the magnitude of the signal was correlated with the extent of myocardium that underwent transient ischemia. The sensitivity of selectivity of the uptake and retention of (99m)Tc-fucoidan in both settings was excellent.

CONCLUSION

This study supports (99m)Tc-fucoidan as a relevant imaging agent for in vivo detection of biologic activities associated with P-selectin overexpression, such as arterial thrombus and ischemic memory. Given the reported wide availability at a low cost, and its low toxicity, fucoidan seems to overcome some of the limitations of previous P-selectin-targeted imaging agents.

Reduced plasma levels of P-selectin and L-selectin in a pilot study from Alzheimer disease: relationship with neuro-degeneration

Neurodegenerative processes associated with Alzheimer's disease (AD) are accompanied by reactive astrogliosis and microglia activation and a role for chronic inflammation in the brain degeneration of these patients has been suggested. Moreover impaired immune functions in AD brains might also influence the disease's progression. Therefore, it is of interest to further characterized inflammatory molecules in the peripheral blood of patients with AD and its relationship with cognitive decline. A complex picture emerged in this pilot study and IL-8, IFN-gamma, MCP-1 and VEGF levels were increased in AD. Levels of P-selectin and L-selectin were decreased in AD and lowest in AD patients with highest cognitive decline. Our findings suggest that these molecules may induce alterations of endothelial regulation and influence neurodegenerative processes of AD.

Pathophysiological levels of soluble P-selectin mediate adhesion of leukocytes to the endothelium through Mac-1 activation

Plasma soluble P-selectin (sP-selectin) levels are increased in pathologies associated with atherosclerosis, including peripheral arterial occlusive disease (PAOD). However, the role of sP-selectin in regulating leukocyte-endothelial adhesion is unclear. The aim of this study was to assess the ability of exogenous and endogenous sP-selectin to induce leukocyte responses that promote their adhesion to various forms of endothelium. In flow chamber assays, sP-selectin dose-dependently increased neutrophil adhesion to resting human iliac artery endothelial cells. Similarly, sP-selectin induced neutrophil adhesion to the endothelial surface of murine aortae and human radial venous segments in ex vivo flow chamber experiments. Using intravital microscopy to examine postcapillary venules in the mouse cremaster muscle, in vivo administration of sP-selectin was also found to significantly increase leukocyte rolling and adhesion in unstimulated postcapillary venules. Using a Mac-1-specific antibody and P-selectin knockout mouse, it was demonstrated that this finding was dependent on a contribution of Mac-1 to leukocyte rolling and endothelial P-selectin expression. This was confirmed in an ex vivo perfusion model using viable mouse aorta and human radial vessels. In contrast, with tumor necrosis factor-alpha-activated endothelial cells and intact endothelium, where neutrophil adhesion was already elevated, sP-selectin failed to further increase adhesion. Plasma samples from PAOD patients containing pathologically elevated concentrations of sP-selectin also increased neutrophil adhesion to the endothelium in a sP-selectin-dependent manner, as demonstrated by immunodepletion of sP-selectin. These studies demonstrate that raised plasma sP-selectin may influence the early progression of vascular disease by promoting leukocyte adhesion to the endothelium in PAOD, through Mac-1-mediated rolling and dependent on endothelial P-selectin expression.

A potential thrombus diagnosis reagent based on P-selectin monoclonal antibody SZ-51 light chain

INTRODUCTION

P-selectin is a well characterized platelet adhesion molecule that can shift from the secretory granules to the surface of activated platelets, which makes it a potential target in thrombus diagnosis and therapy. SZ-51 is a monoclonal antibody against P-selectin.

MATERIALS AND METHODS

To build a potential thrombus diagnosis reagent, we expressed the light chain of SZ-51 (SZ-LC) in P. pastoris and the protein was highly purified by the procedure combining nickel affinity purification, Q-column and Superdex 75 column chromatography. The purified recombinant SZ-LC was labeled with (99m)Tc and used for blood clearance, in vitro platelet binding and dog thrombus binding assay.

RESULTS AND CONCLUSION

The yield of SZ-LC by the expression and purification method reached above 70 mg/L culture. We found that the nucleotide from (99m)Tc-SZ-LC was removed quickly through animal kidney, and (99m)Tc-SZ-LC could bind specifically to the activated human platelet in vitro. More importantly, with this recombinant protein, we successfully detected the fresh thrombus that was induced in dog vein. These results suggested that the recombinant SZ-LC expressed by P. pastoris was functional active and a potential reagent for thrombus diagnosis.

Potential mechanism for recruitment and migration of CD133 positive cells to areas of vascular inflammation

OBJECTIVE

Mast cells are found in large numbers in atherosclerotic plaques. The present study was conducted to determine whether tryptase stimulation of human coronary artery endothelial cells (HCAEC) would lead to an increase in transmigration of CD133 positive cells (CD133+). In vitro these cells can differentiate into mast cells under the influence of specific cytokines and growth factors.

METHODS AND RESULTS

CD133+ cells were isolated from umbilical cord blood. They express mRNA for several adhesion molecules that are also utilized in neutrophil migration and can migrate across an HCAEC monolayer. Migration increased significantly when HCAEC were stimulated with tryptase and decreased when CD133+ cells were pretreated with CV3988, a platelet activating factor receptor (PTAFR) antagonist. Following long-term cell culture, these cells stained positively for the presence of tryptase, a mast cell enzyme.

CONCLUSION

CD133+ cells can be utilized as a mast cell precursor population. The transendothelial migration is facilitated by the presence of tryptase and may utilize the PAF/PTAFR interaction in a manner similar to that involved in neutrophil transmigration. Following transmigration, a subset of these progenitor cells may mature into mast cells in the subendothelial space and play a role in propagation of the inflammatory process in atherosclerosis.

Novel Biomarkers Associated with Deep Venous Thrombosis: A Comprehensive Review

Primary and recurrent venous thromboembolic disease (VTE, deep venous thrombosis and pulmonary embolism) remain a significant source of morbidity and mortality in the hospitalized patient. Non-specific subjective complaints and lack of specific objective findings related to acute deep venous thrombosis (DVT) and pulmonary embolism (PE) complicate the diagnosis. There remains no single serum marker available to exclusively confirm the diagnosis of VTE. While D-dimer is highly sensitive and useful for diagnostic exclusion, it lacks the specificity necessary for diagnostic confirmation resulting in the need for a variety of additional studies (i.e.: duplex ultrasound, venography, V/Q scanning, helical thoracic and pelvic CT scans and pulmoary angiography). There is evolving research supporting the utility of various plasma markers as novel “biomarkers” for VTE including selectins, microparticles, interleukin-10 and other cytokines. This review attempts to examine recent literature assessing the utility of P-selectin, microparticles, D-dimer, E-selectin, thrombin, interleukins and fibrin monomers in the diagnosis and guidance of therapy for VTE.

Microvascular dysfunction in rheumatoid arthritis assessed by laser Doppler anemometry: relationship to soluble adhesion molecules and extraarticular manifestations

In search of a noninvasive diagnostic test for rheumatoid vasculitis (RV), this study addressed the questions whether changes in capillary blood cell velocity (CBV) detected by laser Doppler anemometry in patients with rheumatoid arthritis (RA) were correlated with the levels of soluble adhesion molecules and whether cutaneous flow abnormalities may reflect extraarticular manifestations in RA. In 31 RA patients and 20 patients with osteoarthritis (OA), CBV was measured in the skin above the left ring finger at rest and after 3-min arterial occlusion. Serum levels of soluble intercellular adhesion molecule-1 (sICAM-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin), and soluble P-selectin (sP-selectin) were assessed by enzyme linked immunosorbent assay. Peak CBV was reduced in RA patients compared to OA patients (0.42 +/- 0.07 mm/s vs. 0.70 +/- 0.13 mm/s; P = 0.013). Both CBV during rest and reactive hyperemia were not correlated with the levels of soluble adhesion molecules. There were no significant differences in resting or peak CBV between RA patients with or without extraarticular manifestations. The lack of an inverse correlation between the levels of soluble adhesion molecules and CBV during rest and reactive hyperemia contradicts the assumption that inflammatory vascular damage indicated by increased levels of soluble adhesion molecules was the main reason for the impairment of microcirculation. The present results do not suggest that cutaneous flow abnormalities may reflect extraarticular manifestations in RA.

Cardiology at Westmead Hospital from 1990 to 2007

Professor John Uther was the Director of Cardiology at Westmead Hospital from 1979 to 1990. Professor David Ross and Dr Pramesh Kovoor followed in this capacity subsequently. Networking between Westmead and metropolitan hospitals was established by conjoint appointment of cardiologists across the facilities. Westmead has maintained its excellence in electrophysiology with leadership in operative/catheter ablation of atrial fibrillation, development of catheter for mapping tricuspid annulus, multi-electrode mapping and intramural ablation of ventricular tachycardia and paediatric electrophysiology. Dr. Hugh Paterson became the Director of Cardiothoracic Surgery in 2006. The previous Directors were Dr. David Johnson, Dr. Graham Nunn and Associate Professor Richard Chard. Westmead established an area-wide acute infarct angioplasty service for all patients presenting to any facility in Western Sydney along with triage of chest pain in the ambulance in 2004. Collaborative sessions with vascular surgeons for non-coronary interventions commenced in 2005. In the future, Westmead will continue its excellence in vascular and electrophysiological interventions. Imaging (echocardiography, computerised tomography and magnetic resonance imaging) will be a major part of the service. Innovation in basic science is likely. Overall, it will be an exciting time to be a cardiologist, vascular surgeon or cardiothoracic surgeon at Westmead.

Thrombosis and Thrombolysis: Platelet Membrane Glycoproteins

Over the last quarter of a century, therapy for acute coronary syndromes has rapidly evolved. The major causative factor for acute coronary syndromes, particularly acute myocardial infarction, is now recognised to be coronary thrombosis and therapies using thrombolytic agents to dissolve thrombus or percutaneous coronary interventions (angioplasty and stenting) to mechanically disrupt thrombus and restore vessel patency are now routine. The precipitant for coronary thrombus is believed to be atherosclerotic plaque rupture. Plaque rupture has been demonstrated at autopsy in humans and in vivo in an experimental animal model for atherosclerosis. Thrombus formed at these sites is platelet rich and anti-platelet therapy has an established role in the treatment of cardiovascular disease. The study of platelet membrane glycoproteins, which mediate platelet adhesion and aggregation, has resulted in specific therapies. Future directions for research with clinical relevance include the development of markers for plaque instability.

Protease activation of calcium-independent phospholipase A2 leads to neutrophil recruitment to coronary artery endothelial cells

INTRODUCTION

Thrombin or tryptase cleavage of protease-activated receptors (PAR) on human coronary artery endothelial cells (HCAEC) results in activation of a membrane-associated, calcium-independent phospholipase A2 (iPLA2) that selectively hydrolyzes plasmalogen phospholipids. Atherosclerotic plaque rupture results in a coronary ischemic event in which HCAEC in the ischemic area would be exposed to increased thrombin concentrations in addition to tryptase released by activated mast cells present in the plaque.

MATERIALS AND METHODS

HCAEC were stimulated with thrombin or tryptase in the absence or presence of bromoenol lactone (BEL), a selective iPLA2 inhibitor, and iPLA2 activation, accumulation of biologically active membrane phospholipid-derived metabolites, upregulation of cell surface P-selectin expression and neutrophil adherence were measured.

RESULTS

HCAEC exposed to thrombin or tryptase stimulation demonstrated an increase in iPLA2 activity and arachidonic acid release. Additionally, stimulated HCAEC demonstrated increased platelet-activating factor (PAF) production and cell surface P-selectin expression, resulting in increased adhesion of neutrophils to HCAEC monolayers. Pretreatment with bromoenol lactone to inhibit iPLA2, blocked membrane phospholipid-derived metabolite production, increased cell surface P-selectin expression and neutrophil adherence.

CONCLUSIONS

The similar biochemical and cellular responses in HCAEC exposed to thrombin or tryptase stimulation suggest that the cleavage of two separate PAR serve to extend the range of proteases to which the cells respond rather than resulting in separate intracellular events. This suggests that in conditions such as thrombosis and atherosclerosis that multiple mechanisms can activate the inflammatory response.

Recombinant integrin CD11b A-domain blocks polymorphonuclear cells recruitment and protects against skeletal muscle inflammatory injury in the rat

The beta2 integrin CD11b/CD18 (CR3) is a major adhesion receptor of neutrophils, normally utilized to fend off infections. This receptor contributes, however, to multiple forms of non-infectious inflammatory injury when dysregulated as shown in gene knock-outs and through the use of blocking monoclonal antibodies. The major ligand recognition site of CR3 has been mapped to the A-domain in the CD11b subunit (CD11bA). The recombinant form of this domain exhibits a ligand binding profile similar to that of the holoreceptor. To assess the potential anti-inflammatory activity of CD11bA as a competitive antagonist of CR3 in vivo, we assessed its effects on a developed animal model of traumatic skeletal muscle injury in the rat. Recombinant soluble rat CD11bA-domain fused to glutathione-S-transferase (GST) was administered intravenously in a single dose at 1 mg/kg to nine groups of Wistar rats, five in each group, 30 min before inducing traumatic skeletal muscle injury. Control animals received either a function-blocking anti-CD11b/CD18 monoclonal antibody (1 mg/kg), non-functional mutant forms of the CD11bA (D140GS/AGA, T209/A, D242/A), recombinant GST or buffer alone. In control animals, the wounded muscle showed oedema, erythrocyte extravasation and myonecrosis both within and outside the immediate wounded area (5-10 mm zone) and influx of neutrophils was detected 30 min post-wound, followed by a second wave 3 hr later. Wild-type CD11bA- or anti-CD11b monoclonal antibody (mAb)-treated rats showed a comparable and significant decrease in the number of infiltrating PMN (78 + 4%, n = 70 and 86 +/- 2%, n = 50, respectively) and preservation of the muscular fibres outside the immediate zone of necrosis (75 + 4%, n = 70, 84 +/- 1%, n = 50, respectively), compared to controls. These data demonstrate that CD11bA can be an effective tissue-preserving agent in acute inflammatory muscular injury.

Strong correlation between serum levels of inflammatory mediators and their distribution in infarct-related coronary artery

BACKGROUND

Little is known regarding the correlation between circulating levels of inflammatory mediators and their distribution within the infarct-related coronary artery (ICA).

METHODS AND RESULTS

Atherothrombotic tissue and blood were aspirated by export suction catheter from the ICA in 49 patients with an acute myocardial infarction (AMI) < 6 h duration who underwent primary percutaneous coronary intervention (PCI). Blood samples were collected before PCI for levels of high-sensitivity (hs) C-reactive protein (CRP), soluble P-selectin (sP-selectin) and white blood cell (WBC) counts. Immunohistochemical staining was performed for localization of CRP within the ICA. Staining intensity was graded for macrophage and extracellular tissue (0: no staining; 1+: < 30%, 2+: 30% to 60%, and 3+: > 60%). The hs-CRP levels were markedly higher in grade 3+ compared with both grade 2+ and grade 1+ of macrophage and extracellular staining of CRP (all p values < 0.0001), and in grade 2+ compared with grade 1+ (p < 0.001). Additionally, the ICA had a significantly higher sP-selectin level and WBC count compared with the systemic circulation (p < 0.0001). Furthermore, the ICA level of sP-selectin was noticeably higher in patients with a total atherothrombus volume > or = 0.5 cm3 than in patients with total volume < 0.5 cm3 (p < 0.0001). Moreover, correlation analysis demonstrated that the increase in the ICA level of sP-selectin was significantly related to the increase in the WBC count in the artery (r = 0.548, p < 0.0001). Multiple analysis identified an increased circulating level of hs-CRP as the only independent predictor of > or = 2+ in macrophage (p < 0.0001) and > or = 2+ in extracellular (p < 0.0001) staining of CRP.

CONCLUSIONS

Following AMI, the sP-selectin level and WBC count were markedly higher in the ICA than in the circulation. Moreover, the circulating level of hs-CRP was strongly associated with ICA localization of CRP.

Inflammatory mediators are altered in the acute phase of posttraumatic complex regional pain syndrome

OBJECTIVES

Complex regional pain syndrome type 1 (CRPS 1) is a disorder that can affect an extremity after minor trauma or surgery. The pathogenesis of this syndrome is unclear. It has clinical signs of severe local inflammation as a result of an exaggerated inflammatory response, but neurogenic dysregulation also may contribute to it.

METHODS

For further insights into the pathogenesis of CRPS 1, the authors investigated inflammatory and neurogenic mediators-C-reactive protein (CRP), interleukin-6 (IL-6), interleukin-8 (IL-8), soluble tumor necrosis factor receptor I/II (sTNFR I/II), sE-selectin, sL-selectin, sP-selectin, substance P, neuropeptide Y, and calcitonin gene-related peptide-in venous blood from both the healthy arm and the arm with acute CRPS I from 25 patients and from 30 healthy volunteers.

RESULTS

Levels of IL-8 and sTNFR I/II were significantly elevated in patients, whereas all soluble forms of selectins were significantly suppressed. There was no significant difference in white blood cell count (WBC), CRP, and IL-6. Substance P was significantly elevated in patients. The other two neuropeptides were unchanged. None of the parameters studied showed any differences between the CRPS I-affected arm and the normal arm.

CONCLUSIONS

Elevated IL-8 and sTNFR I/II levels indicate an association between CRPS I and an inflammatory process. Normal WBC, CRP, and IL-6 give evidence for localized inflammation. The hypothesis of neurogenic-induced inflammation mediated by neuropeptides is supported by elevated substance P levels.

From Gene to HSQC in under Five Hours: High-Throughput NMR Proteomics

A simple, rapid, in vitro cell-free protein expression system, Expressway NMR, is introduced and used to express the small ubiquitin-related modifier protein SUMO-1. This 12 kDa molecule is challenging for NMR as it has limited solubility and requires relatively high salt (200 mM) for stability in solution. Starting with the gene, the cell-free system, and milligram amounts of nitrogen-15 isotopically enriched amino acids, sufficient protein is produced in 4 h to obtain a high-resolution 2D HSQC spectrum of the protein in 40 min. This time would be closer to 10 min with the aid of a higher sensitivity salt-tolerant cryogenic NMR probe. With all protein purification steps included, and aggressive data processing using the filter diagonalization method (FDM), it is but 6 h from gene to heteronuclear single quantum coherence (HSQC). As the cell-free system is nearly background-free, it is also possible to work with the crude reaction mixture, in which case only a total of 5 h is required. Sample stability over time, whether crude extract or purified, was notable, with no significant change in the 15N-1H HSQC spectrum over 6 months at 4 degrees C (300 muM, pH 6.1, capped NMR tube). The combination of a turnkey, high-yield, protease-free in vitro protein expression system, an optimized sensitivity-enhanced HSQC pulse sequence, and FDM processing makes this scheme an attractive first step to rapidly assess the suitability of proteins for complete solution structure determination.

Raised Plasma Soluble P-Selectin in Peripheral Arterial Occlusive Disease Enhances Leukocyte Adhesion

Raised levels of soluble P-selectin (sP-selectin) have been reported in the plasma of patients with vascular diseases; however, the functional importance of this ligand remains unclear. In this study we have examined a potential role for plasma sP-selectin in regulating neutrophil adhesion in patients with peripheral arterial occlusive disease (PAOD). Patients with PAOD had significantly higher levels of sP-selectin (mean±SD: 73.3±13.0 versus 16.7±6.4 ng/mL) and enhanced whole blood leukocyte adhesion to platelets under shear. To examine whether the raised sP-selectin levels can directly influence leukocyte adhesion, isolated neutrophils were incubated with plasma from PAOD patients before and after immunodepletion of sP-selectin. Neutrophil adhesion to fibrinogen increased 2-fold following incubation with PAOD plasma, which was abrogated on sP-selectin immunodepletion. We subsequently demonstrated that recombinant sP-selectin dose-dependently (75 to 250 ng/mL) increased leukocyte adhesion to fibrinogen and platelet monolayers. This increase was PSGL-1 and Src kinase-dependent and correlated with an increase in sP-selectin-mediated Mac-1 activation. sP-selectin–stimulated neutrophil adhesion to platelet monolayers was inversely correlated with shear, such that at low shear (50 s −1 ) a 92.7%±15.7 increase in adhesion was observed decreasing to 38.5%±11.9 at 150 s −1 and 10.1%±7.4 at 300 s −1 . These studies suggest a potentially important role for sP-selectin in modulating neutrophil adhesion in patients with PAOD, particularly at sites of low shear, where it raises the possibility that raised plasma sP-selectin levels may enhance leukocyte recruitment to vascular injury and promote disease progression.

Potential role for mast cell tryptase in recruitment of inflammatory cells to endothelium

Recent research suggests that activation of protease-activated receptors (PARs) on the surface of endothelial and epithelial cells may play a role in general mechanisms of inflammation. We hypothesized that mast cell tryptase activation of endothelial cell PAR-2 is coupled to increased calcium-independent PLA2(iPLA2) activity and increased platelet-activating factor (PAF) production that may play a role in inflammatory cell recruitment at sites of vascular injury. Stimulation of human coronary artery endothelial cells (HCAEC) with 20 ng/ml tryptase increased iPLA2activity, arachidonic acid release, and PAF production. These tryptase-stimulated responses were inhibited by pretreatment with the iPLA2-selective inhibitor bromoenol lactone (BEL; 5 μM, 10 min). Similar patterns of increased iPLA2activity and PAF production were also seen when HCAEC were treated with SLIGKV, which represents the tethered ligand sequence for the human PAR-2 once the receptor is cleaved by tryptase. Tryptase stimulation also increased cell surface expression of P-selectin, decreased electrical resistance, and increased neutrophil adherence to the endothelial cell monolayer. The tryptase-stimulated increases in both cell surface P-selectin expression and neutrophil adhesion were also inhibited with BEL pretreatment. We conclude that tryptase stimulation of HCAEC contributes importantly to early inflammatory events after vascular injury by activation of iPLA2, leading to arachidonic acid release, PAF production, cell surface P-selectin expression, and increased neutrophil adherence.

G-matrix Fourier transform NOESY-based protocol for high-quality protein structure determination

A protocol for high-quality structure determination based on G-matrix Fourier transform (GFT) NMR is presented. Five through-bond chemical shift correlation experiments providing 4D and 5D spectral information at high digital resolution are performed for resonance assignment. These are combined with a newly implemented (4,3)D GFT NOESY experiment which encodes information of 4D 15N/15N-, 13C(alipahtic)/15N-, and 13C(aliphatic)/13C(aliphatic)-resolved [1H,1H]-NOESY in two subspectra, each containing one component of chemical shift doublets arising from 4D --> 3D projection at omega1:Omega(1H) +/- Omega(X) [X = 15N,13C(aliphatic)]. The peaks located at the centers of the doublets are obtained from simultaneous 3D 15N/13C(aliphatic)/13C(aromatic)-resolved [1H,1H]-NOESY, wherein NOEs detected on aromatic protons are also obtained. The protocol was applied for determining a high-quality structure of the 14 kDa Northeast Structural Genomics consortium target protein, YqfB (PDB ID ). Through-bond correlation and NOESY spectra were acquired, respectively, in 16.9 and 39 h (30 h for shift doublets, 9 h for central peaks) on a 600 MHz spectrometer equipped with a cryogenic probe. The rapidly collected highly resolved 4D NOESY information allows one to assign the majority of NOEs directly from chemical shifts, which yields accurate initial structures "within" approximately 2 angstroms of the final structure. Information theoretical "QUEEN" analysis of initial distance limit constraint networks revealed that, in contrast to structure-based protocols, such NOE assignment is not biased toward identifying additional constraints that tend to be redundant with respect to the available constraint network. The protocol enables rapid NMR data collection for robust high-quality structure determination of proteins up to approximately 20-25 kDa in high-throughput.

SOLUBLE BIO-MARKERS IN VASCULAR DISEASE: MUCH MORE THAN GAUGES OF DISEASE?

1. In recent years demonstration of a direct association between slightly elevated serum levels of soluble proteins including the acute phase response proteins, selectins and intercellular adhesion molecules and the risk of developing vascular disease have been widely reported. These studies may provide the clinician with an insight into disease diagnosis, prognosis and disease activity. 2. The simplest interpretation of this data is that soluble proteins are just sensitive markers of inflammation. However, they may in fact be modulating inflammation directly through interaction with circulating cells. 3. Recent work has shown that these soluble proteins do indeed remain active and can bind to functional ligands expressed by circulating leucocytes. The current review focuses on the soluble proteins C-reactive protein and soluble P-selectin and describes previous studies characterizing their interaction with immune cells to modulate the pathogenesis of vascular disease. 4. The current review focuses on the soluble proteins C-reactive protein and soluble P-selectin and describes previous studies characterizing their interaction with immune cells to modulate the pathogenesis of vascular disease.

The effects of standard anthracycline-based chemotherapy on soluble ICAM-1 and vascular endothelial growth factor levels in breast cancer

PURPOSE

The circulating soluble form of intercellular adhesion molecule-1 (sICAM-1) and vascular endothelial growth factor (VEGF) are elevated in women with breast cancer and associated with tumor progression and poor prognosis. This study examined the effects of anthracycline-based chemotherapy on plasma sICAM-1 and VEGF, as well as soluble P-selectin, von Willebrand factor, and interleukin-6 levels.

EXPERIMENTAL DESIGN

Twenty-six women diagnosed with stage I-IIIA breast cancer (mean age, 48.4 +/- 10.4 years; range, 34-79 years) were studied before (week 1) and at weeks 2 and 3 of cycles 1 and 4 of chemotherapy.

RESULTS

The initial effect of chemotherapy was to reduce sICAM-1 levels; compared with pretreatment, sICAM-1 levels were decreased at week 2 of both cycles (P values < 0.01). sICAM-1 levels were elevated, however, at the start of cycle 4 as compared with pretreatment (P < 0.01). Chemotherapy led to an increase in sICAM-1 levels in node-positive but not node-negative patients (P < 0.01). VEGF levels were decreased at week 2 of cycle 4 (P = 0.001) and remained so at week 3. Similar to sICAM-1, VEGF levels were elevated at the start of cycle 4 as compared with pretreatment (P < 0.006). Soluble P-selectin levels decreased during week 2 of cycle 4 (P = 0.026). Neither interleukin-6 or von Willebrand factor were significantly changed in response to chemotherapy.

CONCLUSIONS

The findings support prior studies suggesting that sICAM-1 levels derive from sources other than endothelial cells. In addition, whereas the more immediate effect of chemotherapy is to reduce sICAM-1 and VEGF, continued treatment may lead to significant elevations.

Pathobiology and cell interactions of platelets in diabetes

Diabetes is a well-recognised risk factor for atherosclerotic cardiovascular disease and in fact most diabetic patients die from vascular complications. The Diabetes Control and Complications Trial (DCCT) and the U.K. Prospective Diabetes Study (UKPDS) indicate a consistent relationship between hyperglycaemia and the incidence of chronic vascular complications in patients with diabetes. Platelets are essential for haemostasis, and abnormalities of platelet function may cause vascular disease in diabetes. Diabetic patients have hyperreactive platelets with exaggerated adhesion, aggregation and thrombin generation. In summary, the entire coagulation cascade is dysfunctional in diabetes. This review provides a comprehensive overview of the physiological role of platelets in maintaining haemostasis and of the pathophysiological processes that contribute to platelet dysfunction in diabetes and associated cardiovascular diseases, with special emphasis on proteomic approaches and leukocyte-platelet cross-talk.

Rolling of Th1 Cells via P-Selectin Glycoprotein Ligand-1 Stimulates LFA-1-Mediated Cell Binding to ICAM-1

Activated T cells migrate from the blood into nonlymphoid tissues through a multistep process that involves cell rolling, arrest, and transmigration. P-Selectin glycoprotein ligand-1 (PSGL-1) is a major ligand for P-selectin expressed on subsets of activated T cells such as Th1 cells and mediates cell rolling on vascular endothelium. Rolling cells are arrested through a firm adhesion step mediated by integrins. Although chemokines presented on the endothelium trigger integrin activation, a second mechanism has been proposed where signaling via rolling receptors directly activates integrins. In this study, we show that Ab-mediated cross-linking of the PSGL-1 on Th1 cells enhances LFA-1-dependent cell binding to ICAM-1. PSGL-1 cross-linking did not enhance soluble ICAM-1 binding but induced clustering of LFA-1 on the cell surface, suggesting that an increase in LFA-1 avidity may account for the enhanced binding to ICAM-1. Combined stimulation by PSGL-1 cross-linking and the Th1-stimulating chemokine CXCL10 or CCL5 showed a more than additive effect on LFA-1-mediated Th1 cell adhesion as well as on LFA-1 redistribution on the cell surface. Moreover, PSGL-1-mediated rolling on P-selectin enhanced the Th1 cell accumulation on ICAM-1 under flow conditions. PSGL-1 cross-linking induced activation of protein kinase C isoforms, and the increased Th1 cell adhesion observed under flow and also static conditions was strongly inhibited by calphostin C, implicating protein kinase C in the intracellular signaling in PSGL-1-mediated LFA-1 activation. These results support the idea that PSGL-1-mediated rolling interactions induce intracellular signals leading to integrin activation, facilitating Th1 cell arrest and subsequent migration into target tissues.

Serum VCAM-1, ICAM-1, and L-selectin levels in children and young adults with chronic renal failure

Children and young adults with chronic renal failure (CRF) present with an impaired immune response. Our aim was to analyze whether leukocyte migration, determined by adhesion molecules, is disturbed in the course of CRF, hemodialysis (HD), and peritoneal dialysis (PD). Soluble (s) VCAM-1, ICAM-1, and L-selectin serum levels were evaluated by ELISA in 15 patients with CRF, 22 patients on cuprophane membrane HD, 24 patients on PD, and in 15 controls. The sVCAM-1 levels in all groups were significantly elevated compared with controls. The levels in HD patients were higher than in CRF patients (P<0.05), while levels in PD patients were higher than in CRF and HD (P<0.001 and P<0.01, respectively). The sICAM-1 concentrations in CRF and PD patients were significantly elevated compared with controls (P<0.001 and P<0.0001, respectively); in PD patients sICAM-1 levels were higher than in HD patients (P<0.001), but there were no differences between other groups. sL-selectin levels were decreased in all groups compared with controls. The levels in HD patients were the lowest and the differences, compared with CRF and PD patients, were significant (P<0.05 and P<0.01, respectively). Children and young adults with CRF and on maintenance dialysis have altered concentrations of soluble adhesion molecules, resulting from either inadequate clearance or disturbed synthesis and release. The differences in sVCAM-1 levels between CRF and both groups of patients on dialysis, as well as the differences in sL-selectin concentrations between HD and CRF patients, indicate that these disturbances are aggravated by maintenance dialysis, particularly HD.

Relationships between platelets and inflammatory markers in rheumatoid arthritis

AIM OF THE STUDY

To investigate platelets and different inflammatory markers in conjunction with a substantial inflammatory reaction. We used individuals with active rheumatoid arthritis (RA) as an experimental cohort.

METHODS

We selected 16 patients with active RA having at least one affected joint. On day 1, platelet and neutrophil counts together with C-reactive protein (CRP) were determined. We further analysed platelet volume (MPV) and plasma levels of thrombopoietin (TPO), P-selectin, myeloperoxidase and interleukin 6 (IL-6). After 2 years when all patients failed to show any swollen joints all analyses were repeated.

RESULTS AND CONCLUSIONS

As expected platelet count, CRP and IL-6 were elevated in active RA. The measures correlated with each other thus reflecting the same characteristic of the inflammatory response. The neutrophil count, MPV and myeloperoxidase also mirror disease activity. They failed to correlate with other activity markers thus providing unique information. MPV and myeloperoxidase on day 1 correlated with recovery values. Therefore, they could be suitable to use when following the inflammatory reaction over a long period of time.

Soluble adhesion molecules in children and young adults on chronic hemodialysis

Children on chronic hemodialysis (HD) present with impaired immunity that may result from disturbances in leukocyte migration, caused by changes in expression of adhesion molecules on endothelium and immunocompetent cells. However, it is still not clear whether the type of dialyzer or a single dialysis session influences the concentrations of soluble adhesion molecules in these patients. We evaluated by ELISA serum levels of soluble (s) VCAM-1, ICAM-1, L-selectin, and P-selectin in 22 patients on cuprophane HD (CU), 8 on polysulfone HD (PS), 10 on vitamin E-modified cellulose HD (VE), and 15 controls. In all HD patients, sVCAM-1 levels were elevated compared with controls and were higher in CU than in VE. The sICAM-1 concentrations were increased in VE compared with controls, but remained unchanged in CU and PS. The sL-selectin levels were reduced in all HD patients. The mean values of sP-selectin were comparable in CU, PS, and controls. The lowest levels were observed in VE. In CU patients, sVCAM-1, sICAM-1, and sP-selectin concentrations rose after HD. A single PS session had no impact on adhesion molecules, whereas a VE session increased the level of sVCAM-1. The type of dialysis membrane may change the profile of adhesion molecule concentrations, thus influencing the immune system of a child on HD. The increase in levels of adhesion molecules in the course of a single HD session, which was pronounced in CU and VE patients, suggests poor biocompatibility of these dialyzers.

Independent pathways of P-selectin and complement-mediated renal ischemia/reperfusion injury

Evidence from in vitro studies indicates that complement activation regulates the expression of P-selectin on endothelial cells. This suggests that in disorders such as ischemia/reperfusion injury, in which both complement and P-selectin have been shown to play a role, complement activation is a primary event and the effects of P-selectin are secondary. To test this hypothesis in vivo, we examined a mouse kidney model of ischemia/reperfusion injury. Surprisingly, the time course and extent of expression of P-selectin was unaltered in C3-deficient mice compared with wild-type mice, in which there was rapid but transient up-regulation of P-selectin on capillary walls and slower accumulation of complement split product on the tubular epithelium. In addition, treatment with anti-P-selectin antibody to reduce the neutrophil-mediated reperfusion damage was equally effective in the absence of C3. These data imply that complement and P-selectin-mediated pathways of renal reperfusion injury are mutually independent, a conclusion that is possibly explained by the differences in the location and time kinetics of complement activation and P-selectin expression. We conclude that in vivo interaction between complement and P-selectin is limited because of time and spatial considerations. Consequently, complement and P-selectin pose distinct targets for therapy.

Characterization of platelet and soluble-porcine P-selectin (CD62P)

P-selectin (CD62P), an adhesion molecule expressed on activated endothelial cells and platelets, mediates the initial attachment of leukocytes to the stimulated endothelium upon inflammation and the interaction between leukocytes and platelets. A soluble form of P-selectin is present in the serum of healthy individuals as a circulating protein and high levels have been described in various pathological situations. The aim of this study was to characterize P-selectin on porcine platelets and investigate the soluble form of this protein, which are uncharacterized in several animal species including pigs. A new monoclonal antibody (mAb) (SwPsel.1.9) against porcine P-selectin was produced using a mouse cell line transfected with pig P-selectin cDNA. This mAb together with a previously described mAb (P-sel.KO.2.5), produced in our laboratory, was used to develop an ELISA to quantify porcine P-selectin. No significant levels of soluble-porcine P-selectin were observed in healthy animals. However, the total amount of P-selectin measured in porcine platelets was similar to that found in humans. Increased levels of this circulating protein were detected in the plasma from pigs after allograft implantation. In vitro, P-selectin expression on platelet membrane was rapidly induced by PMA and thrombin, as assessed by flow cytometry. However, these activators did not stimulate the release of soluble P-selectin. Analysis of the proteolytic cleavage of this protein from COS-transfected cells revealed that PMA treatment failed to cause the shedding of membrane-bound P-selectin. These data suggest that porcine P-selectin is a suitable marker for inflammation and that the mechanism involved in the generation of circulating P-selectin is not proteolytic release.

Pseudomultidimensional NMR by Spin-State Selective Off-Resonance Decoupling

An alternate technique for accurately monitoring the chemical shift in multidimensional NMR experiments using spin-state selective off-resonance decoupling is presented here. By applying off-resonance decoupling on spin S during acquisition of spin I, we scaled the scalar coupling J(I,S) between the spins, and the residual scalar coupling turns out to be a function of the chemical shift of spin S. Thus, the chemical shift information of spin S is indirectly retained, without an additional evolution period and the accompanying polarization transfer elements. The detection of the components of the doublet using spin-state selection enables an accurate measurement of the residual scalar coupling and a precise value for the chemical shift, concomitantly. The spin-state selection further yields two subspectra comprising either one of the two components of the doublet and thereby avoiding the overlap problems that arise from off-resonance decoupling. In general, spin-state selective off-resonance decoupling can be incorporated into any pulse sequence. Here, the concept of spin-state selective off-resonance decoupling is applied to 3D (13)C or (15)N-resolved [(1)H,(1)H]-NOESY experiments, adding the chemical shift of the heavy atom attached to the hydrogen ((13)C or (15)N nuclei) with high resolution resulting in a pseudo-4D. These pseudo-4D heavy-atom resolved [(1)H, (1)H]-NOESY experiments contain chemical shift information comparable to that of 4D (13)C or (15)N-resolved [(1)H,(1)H]-NOESY, but with an increase in chemical shift resolution by 1-2 orders of magnitude.

Adhesion to E-selectin promotes growth inhibition and apoptosis of human and murine hematopoietic progenitor cells independent of PSGL-1

Although both P- and E-selectin are constitutively expressed on bone marrow endothelial cells, their role in the regulation of hematopoiesis has only recently been investigated. We have previously shown that P-selectin glycoprotein ligand-l (PSGL-1/CD162) is expressed by primitive human bone marrow CD34+ cells, mediates their adhesion to P-selectin, and, more importantly, inhibits their proliferation. We now demonstrate that adhesion to E-selectin inhibits the proliferation of human CD34+ cells isolated either from human umbilical cord blood, adult mobilized blood, or steady-state bone marrow. Furthermore, a subpopulation, which does not contain the most primitive hematopoietic progenitor cells, undergoes apoptosis following E-selectin-mediated adhesion. The same phenomenon was observed in cells isolated from mouse bone marrow. Using lineage-negative Sca-1+ c-KIT+ bone marrow cells from PSGL-1(-/-) and wild-type mice, we establish that PSGL-1 is not the ligand involved in E-selectin-mediated growth inhibition and apoptosis. Moreover, stable transfection of the human myeloid cell line K562 (which does not express PSGL-1) with alpha(1,3) fucosyltransferase VII alone was sufficient to recapitulate the E-selectin-mediated growth inhibition and apoptosis observed in hematopoietic progenitor cells. These data demonstrate that an E-selectin ligand(s) other than PSGL-1 transduces growth inhibitory and proapoptotic signals and requires posttranslational fucosylation to be functional.

Hypoxia reduces CD80 expression on monocytes but enhances their LPS-stimulated TNF-alpha secretion

Monocytes/macrophages in ischemic tissues are involved in inflammation and suppression of adaptive immunity via secretion of proinflammatory cytokines and reduced ability to trigger T cells, respectively. We subjected human mononuclear cells and mouse macrophages to hypoxia and reoxygenation, the main constituents of ischemia and reperfusion, and added lipopolysaccharide (LPS) to simulate bacterial translocation, which frequently accompanies ischemia. We monitored the secretion of tumor necrosis factor alpha (TNF-alpha) and the surface expression of human leukocyte antigen-DR and the costimulatory molecules CD80 and CD86 on monocytes/macrophages. Hypoxia selectively reduced the surface expression of CD80 (P<0.01), and synergistically with LPS, it enhanced TNF-alpha secretion (P<0.003). Reoxygenation reversed both phenomena. In the mouse macrophage cell line RAW 264.7, hypoxia reduced the surface expression of CD80 and increased its concentrations in the supernatants (P<0.01). Down-regulation of the mRNA coding for the membrane-anchored CD80 was observed, suggesting that hypoxia triggers alternative splicing to generate soluble CD80. Cumulatively, these results suggest that hypoxia simultaneously affects monocytes/macrophages to enhance inflammation and reduce their ability to initiate adaptive-immunity responses associated with ischemic injury.

Hypercholesterolemia promotes P-selectin-dependent platelet-endothelial cell adhesion in postcapillary venules

OBJECTIVE

The objectives of this study were to determine whether hypercholesterolemia promotes platelet-endothelial cell (P/E) adhesion in murine postcapillary venules and define the contributions of endothelial or platelet associated P-selection to hypercholesterolemia-induced P/E interactions.

METHODS AND RESULTS

Wild-type (WT) or P-selectin deficient (P-sel-/-) platelets were isolated and labeled with the fluorochrome CFSE and administered to either WT or P-sel-/- mice placed on a normal diet (ND) or high cholesterol diet (HCD). Intravital videomicroscopy was used to quantify platelet saltation and firm adhesion. HCD-WT mice exhibited a time-dependent increase in P/E cell interactions (relative to ND-WT). Flow cytometry revealed an increased expression of P-selectin on circulating platelets of HCD-WT mice at 2 weeks compared with ND-WT mice. When WT platelets were monitored in HCD-P-sel-/- mice, P/E adhesion was dramatically reduced. However, when P-sel-/- platelets were monitored in HCD-WT recipients, P/E adhesive interactions were reduced even further, comparable to ND-WT mice.

CONCLUSIONS

These results indicate that elevated cholesterol levels promote P/E adhesion in postcapillary venules and that whereas both endothelial and platelet P-selectin contribute to hypercholesterolemia-induced recruitment of platelets, platelet-associated P-selectin seems to play a more important role in producing the prothrombogenic phenotype in venules.

Blockade of p38alpha MAPK ameliorates acute inflammatory renal injury in rat anti-GBM glomerulonephritis

The p38 mitogen-activated protein kinase (MAPK) pathway is a pro-inflammatory signal transduction pathway. The aim of this study was to examine the role of this pathway in acute renal inflammation. Immunostaining localized components of the p38 MAPK pathway (p38alpha, p-p38, p-ATF-2) in normal glomeruli, to podocytes, and occasional endothelial cells. This study identified an eightfold increase in glomerular activation of p38 MAPK (phosphorylated p38, p-p38) within 3 h of the induction of rat anti-glomerular basement membrane (GBM) glomerulonephritis and localized p-p38 and p-ATF-2 to infiltrating neutrophils, with increased staining of podocytes and endothelial cells. The relevance of these findings to human acute inflammatory renal disease was determined by examination of biopsy specimens. In patients with post-infectious glomerulonephritis, there was an increased number of positive p-p38 glomerular cells, including p-p38 staining of infiltrating neutrophils, compared with normal human kidney. In rats, administration of a specific p38 MAPK inhibitor, NPC 31145, before induction of anti-GBM disease prevented a loss of renal function and substantially reduced proteinuria. The reduction in renal injury was attributed to a 55% reduction in glomerular neutrophil infiltration and a 68% reduction in platelet accumulation. This was associated with an abrogation of glomerular P-selectin immunostaining and inhibition of glomerular P-selectin gene expression. In summary, this study has localized the components of the p38 MAPK pathway to cells in normal and diseased rat and human kidney and identified a number of important mechanisms by which signaling through the p38 MAPK pathway induces inflammatory renal disease. Blockade of the p38 pathway may be a novel therapeutic strategy for the treatment of acute renal inflammation.

Individual variations of platelet inhibition after loading doses of clopidogrel

OBJECTIVE

To investigate individual variations of platelet inhibition after clopidogrel-loading doses.

SETTING

Department of Cardiology, Linköping University Hospital, Linköping, Sweden.

SUBJECTS

Individuals with stable angina pectoris (n = 18) subject to percutaneous coronary interventions (PCI) and subsequent stenting were investigated. METHODS AND EXPERIMENTAL PROTOCOL: A 300-mg clopidogrel loading dose was administrated immediately after stenting (day 1) followed by an additional 75 mg clopidogrel after 24 h (day 2). The ADP-evoked platelet fibrinogen binding was analysed to estimate platelet reactivity immediately before angiography and on day 2. A flow cytometry technique was used with two ADP solutions (final concentrations 0.6 and 1.7 micromol L-1) employed as platelet activating agents. Soluble P-selectin was used as a marker of platelet activity.

RESULTS

When using 1.7 micromol L-1 ADP to activate platelets four individuals had a strong inhibition (i.e. platelet reactivity <10% of the day 1-value day 2). In contrast, five patients demonstrated a weak inhibition (i.e. platelet reactivity >60% of the day 1-value day 2). Similar results were obtained when using 0.6 micromol L-1 ADP as a platelet-activating agent. Clopidogrel, however, fails to suppress platelet activity as estimated from soluble P-selectin.

CONCLUSIONS

Clopidogrel evoked platelet inhibition exhibits a considerable individual heterogeneity. Some individuals only had weak responses whereas others displayed strong platelet inhibition. The present flow cytometry technique appears suitable for identifying patients with abnormal reactions after clopidogrel exposure.

Human platelets express heat shock protein receptors and regulate dendritic cell maturation

Immunizations using the endoplasmic reticulum-resident heat shock protein Gp96 induce specific immune responses. Specificity is based on the major histocompatibility complex class I-restricted cross-presentation of Gp96-associated peptides derived from endogenous proteins. Initiation of the immune response depends on the ability of Gp96 to induce the production of proinflammatory cytokines by macrophages and dendritic cells (DCs) and of their maturation in a fashion presumably independent of associated peptide. Both events are mediated by Gp96 receptors on antigen-presenting cells. It is known that Gp96 is released from cells at necrosis induced, for example, by virus infection. Although this event supports the efficient induction of immune responses, it might also interfere with processes that are susceptible to chronic inflammation, such as wound healing after tissue damage. Therefore, Gp96-mediated stimulation of the immune system requires tight regulation. Here we show that human thrombocytes specifically interact with Gp96 and that binding of Gp96 to platelets is enhanced more than 10-fold on activation by thrombin. Gp96 interferes with neither thrombin-induced platelet activation nor platelet aggregation. However, the presence of platelets during Gp96-mediated DC activation reduces the secretion of proinflammatory cytokines and the activation of DCs. This effect is independent of soluble platelet factors and cell-to-cell contact between DCs and thrombocytes. Thus, we provide evidence for a regulatory mechanism that neutralizes Gp96 molecules systemically, especially in the blood. This effect might be of significance in wounds in which chronic inflammation and immune responses against autoantigens have to be prevented.

Circulating endothelial adhesion molecules (sE-selectin, sVCAM-1 and sICAM-1) during rHuG-CSF-stimulated stem cell mobilization

The role of leukocyte-endothelial cell interactions during granulocyte colony-stimulating factor (G-CSF)-induced stem cell mobilization is unclear. To examine endothelial activation during this process, we determined levels of circulating endothelial adhesion molecules in healthy donors undergoing G-CSF-mobilized stem cell collection. Plasma levels of soluble (s) E-selectin, soluble intercellular adhesion molecule-1 (sICAM-1), and soluble vascular cell adhesion molecule-1 (sVCAM-1) were serially determined by enzyme-linked immunosorbent assays in 10 healthy donors during G-CSF-stimulated stem cell mobilization. There was a significant increase in plasma levels of all three endothelial adhesion molecules (sE-selectin, p = 0.01; sICAM-1, p = 0.003; sVCAM-1, p = 0.0002) between day 1 and day 5 of G-CSF stimulation, but only sVCAM-1 concentrations exceeded the range obtained from unstimulated controls in all stem cell donors. Increases of sCAM were accompanied by increased numbers of white blood cells and CD34(+) progenitors in peripheral blood. G-CSF-stimulated peripheral blood progenitor cells (PBPC) mobilization results in increased levels of circulating endothelial adhesion molecules that were most evident for VCAM-1 molecules. Because soluble VCAM-1 remains active in binding to the VLA-4 receptor on CD34(+) cells, it may reduce stem cell adhesiveness to endothelial cells and to bone marrow microenvironment.