Endothelial cell biology. Adhesion molecules involved in the microvascular inflammatory response

A systematic review and meta-analysis of circulating adhesion molecules in rheumatoid arthritis

BACKGROUND

The availability of robust biomarkers of endothelial activation might enhance the identification of subclinical atherosclerosis in rheumatoid arthritis (RA). We investigated this issue by conducting a systematic review and meta-analysis of cell adhesion molecules in RA patients.

METHODS

We searched electronic databases from inception to 31 July 2023 for case-control studies assessing the circulating concentrations of immunoglobulin-like adhesion molecules (vascular cell, VCAM-1, intercellular, ICAM-1, and platelet endothelial cell, PECAM-1, adhesion molecule-1) and selectins (E, L, and P selectin) in RA patients and healthy controls. Risk of bias and certainty of evidence were assessed using the JBI checklist and GRADE, respectively.

RESULTS

In 39 studies, compared to controls, RA patients had significantly higher concentrations of ICAM-1 (standard mean difference, SMD = 0.81, 95% CI 0.62-1.00, p < 0.001; I2 = 83.0%, p < 0.001), VCAM-1 (SMD = 1.17, 95% CI 0.73-1.61, p < 0.001; I2 = 95.8%, p < 0.001), PECAM-1 (SMD = 0.82, 95% CI 0.57-1.08, p < 0.001; I2 = 0.0%, p = 0.90), E-selectin (SMD = 0.64, 95% CI 0.42-0.86, p < 0.001; I2 = 75.0%, p < 0.001), and P-selectin (SMD = 1.06, 95% CI 0.50-1.60, p < 0.001; I2 = 84.8%, p < 0.001), but not L-selectin. In meta-regression and subgroup analysis, significant associations were observed between the effect size and use of glucocorticoids (ICAM-1), erythrocyte sedimentation rate (VCAM-1), study continent (VCAM-1, E-selectin, and P-selectin), and matrix assessed (P-selectin).

CONCLUSIONS

The results of our study support a significant role of cell adhesion molecules in mediating the interplay between RA and atherosclerosis. Further studies are warranted to determine whether the routine use of these biomarkers can facilitate the detection and management of early atherosclerosis in this patient group. PROSPERO Registration Number: CRD42023466662.

Metabolic Adjustments by LncRNAs in Peripheral Neutrophils Partly Account for the Complete Compensation of Asymptomatic MMD Patients

BACKGROUND

Due to the recent development of non-invasive examinations, more asymptomatic patients with Moyamoya Disease (MMD) have been diagnosed than ever. However, its underlying molecular mechanisms and clinical intervention guidelines are all still obscure.

METHODS

Microarray was used to explore those differentially expressed mRNAs and lncRNAs in peripheral neutrophils of asymptomatic MMD patients. Then enrichment analyses based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for those differentially expressed mRNAs and lncRNA associated mRNAs were performed for underlying molecular mechanisms.

RESULTS

Here, we identified a total of 2824 differentially expressed lncRNAs and 522 differentially expressed mRNAs (fold change > 2 and P<0.05) in peripheral neutrophils of asymptomatic MMD patients, compared with healthy controls. Then enrichment analyses based on GO and KEGG showed that the neighboring protein-coding mRNAs of those up-regulated and down-regulated lncRNAs were mainly involved in distinct metabolic processes respectively, which may act as a complementary response to insufficient blood supplies in MMD. Further enrichment analyses of those differentially expressed mRNAs preferentially listed essential physiological processes such as peptide cross-linking, chromatin assembly among others. Moreover, altered mRNAs also revealed to be enriched in renin secretion, platelet activation, inflammation and others.

CONCLUSION

We demonstrated for the first time that metabolic adjustments by dysregulated lncRNAs in peripheral neutrophils might partially account for the complete compensation of asymptomatic MMD patients. In addition, more attention should be paid on renin secretion and platelet activation in order to better understand the pathogenesis and guide clinical intervention for asymptomatic MMDs.

Tumor necrosis factor alpha expression is increased in maternal microvascular endothelial cells in preeclampsia

Objective: The aim of this study was to explore the expression and effects of tumor necrosis factor alpha (TNFα) in maternal endothelial cells in preeclampsia (PE).Methods: Expression levels in primary microvascular endothelial cells (MVEC) isolated from patients with severe preeclampsia (PE) and normal pregnancies were determined by RT-qPCR with or without treatment of TNFα and inhibitors for downstream signaling.Results: PE MVEC exhibited increased basal TNFα expression. TNFα treatment increased TNFα, VCAM, and endocan expression in MVEC.Conclusion: TNFα expression is increased in PE MVEC and the treatment of these cells with exogenous TNFα modifies their gene expression.

Histological and hematological alterations of silver catfish Rhamdia quelen highly parasitized by Lernaea cyprinacea

The main objective of this study was to evaluate the histological and hematological alterations of silver catfish Rhamdia quelen (Quoy & Gaimard, 1824) against intense parasitism by anchor worm Lernaea cyprinacea Linnaeus, 1758. Thirteen fish specimens were collected at the Fish Genetic Improvement Unit (EPAGRI/CEDAP), Brazil. After acclimatization, the fish were anesthetized for blood collection, and the samples were used for counting thrombocytes, total leukocytes, differential leukocytes and for quantification of total erythrocytes. Afterwards, the animals were euthanized, the parasites removed and quantified, and the portions of the affected tegument fixed in 10% buffered formalin. All the analyzed animals were parasitized by L. cyprinacea with mean intensity of 192 specimens per fish. The hematological profile of the animals was different from that reported for healthy fish. Immature leukocytes were the most abundant cells, followed by monocytes, lymphocytes, neutrophils, and periodic acid-Schiff-positive granular leukocytes. A small number of neutrophils were present in the bloodstream of parasitized fish, while histological examination evidenced the accumulation of this cell type near the place of infection by the parasite. Total leukocytes correlated significantly and positively (r = 0.6, p = 0.030) with the intensity of L. cyprinacea infection and the fish weight. Histological changes included hemorrhage, liquefactive necrosis and connective tissue disarrangement, necrosis, granulomatous inflammation, mononuclear and polynuclear inflammation, as well as hyperplasia and hypertrophy of the alarm and mucous cells. The L. cyprinacea infection intensity caused deleterious changes both in the hematological profile and the integument of R. quelen, confirming the pathogenic potential of this parasite to the affected fish species.

The profiles of soluble adhesion molecules in the "great obstetrical syndromes". J Matern Fetal Neonatal Med 2018;32:2113-2136. [PMID: 29320948 DOI: 10.1080/14767058.2018.1427058]

OBJECTIVE

The objective of this study was to determine the profiles of maternal plasma soluble adhesion molecules in patients with preeclampsia, small-for-gestational-age (SGA) fetuses, acute pyelonephritis, preterm labor with intact membranes (PTL), preterm prelabor rupture of the membranes (preterm PROM), and fetal death.

MATERIALS AND METHODS

A cross-sectional study was conducted to determine maternal plasma concentrations of sE-selectin, sL-selectin, and sP-selectin as well as sICAM-1, sVCAM-1, and sPECAM-1 in patients with (1) an uncomplicated pregnancy (control, n = 100); (2) preeclampsia (n = 94); (3) SGA fetuses (in women without preeclampsia/hypertension, n = 45); (4) acute pyelonephritis (n = 25); (5) PTL (n = 53); (6) preterm PROM (n = 24); and (7) fetal death (n = 34). Concentrations of soluble adhesion molecules and inflammatory cytokines (tumor necrosis factor (TNF)-α and interleukin (IL)-8) were determined with sensitive and specific enzyme-linked immunoassays.

RESULTS

In comparison to women with a normal pregnancy, (1) women with preeclampsia had higher median concentrations of sE-selectin, sP-selectin, and sVCAM-1, and a lower concentration of sL-selectin (all p values < .001); (2) patients with SGA fetuses had higher median concentrations of sE-selectin, sP-selectin, and sVCAM-1 (all p values < .05); (3) patients with a fetal death had higher median concentrations of sE-selectin and sP-selectin (all p values < .05); (4) patients with acute pyelonephritis had higher median plasma concentrations of sE-selectin, sICAM-1, and sVCAM-1 (all p values < .001); (5) patients with preeclampsia and acute pyelonephritis, plasma concentrations of sVCAM-1, sE-selectin, and sP-selectin correlated with those of the proinflammatory cytokines TNF-α and interleukin (IL)-8 (all p values < .05); (6) patients with PTL had a higher median concentration of sP-selectin and a lower median concentration of VCAM-1 (all p values < .05); and (7) women with preterm PROM had lower median concentrations of sL-selectin and sVCAM-1 (all p values < .05).

CONCLUSIONS

The results of this study show that endothelial cell activation/dysfunction reflected by the plasma concentration of sE-selectin is not specific to preeclampsia but is present in pregnancies complicated by SGA fetuses, acute pyelonephritis, and fetal death. Collectively, we report that each obstetrical syndrome appears to have a stereotypical profile of soluble adhesion molecules in the peripheral circulation.

Preoperative Platelet Count Predicts Lower Extremity Free Flap Thrombosis: A Multi-Institutional Experience

BACKGROUND

Thrombocytosis in patients undergoing lower extremity free tissue transfer may be associated with increased risk of microvascular complications. This study assessed whether preoperative platelet counts predict lower extremity free flap thrombosis.

METHODS

All patients undergoing lower extremity free tissue transfer at Duke University from 1997 to 2013 and at the University of Pennsylvania from 2002 to 2013 were retrospectively identified. Logistic regression was used to assess whether preoperative platelet counts independently predict flap thrombosis, controlling for baseline and operative factors.

RESULTS

A total of 565 patients underwent lower extremity free tissue transfer, with an overall flap thrombosis rate of 16 percent (n = 91). Elevated preoperative platelet counts were independently associated with both intraoperative thrombosis (500 ± 120 versus 316 ± 144 × 10/liter; p < 0.001) and postoperative thrombosis (410 ± 183 versus 320 ± 143 × 10/liter; p = 0.040) in 215 patients who sustained acute lower extremity trauma within 30 days before reconstruction. In acute trauma patients, preoperative platelet counts predicted a four-fold increased risk of intraoperative thrombosis (cutoff value, 403 × 10/liter; OR, 4.08; p < 0.001) and a two-fold increased risk of postoperative thrombosis (cutoff value, 361 × 10/liter; OR, 2.16; p = 0.005). In patients who did not sustain acute trauma, preoperative platelet counts predicted a four-fold increased risk of intraoperative thrombosis (cutoff value, 352 × 10/liter; OR, 3.82; p = 0.002).

CONCLUSIONS

Acute trauma patients with elevated preoperative platelet counts are at increased risk for lower extremity free flap complications. Prospective evaluation is warranted for guiding risk stratification and targeted treatment strategies.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Risk, III.

Circulating endothelial mediators in human pancreatitis-associated lung injury

OBJECTIVES

To investigate the role of endothelial cell mediators, E-selectin (ES), intercellular adhesion molecule-1 (ICAM-1), tissue factor (TF), and von Willebrand factor (vWF), in the early phase of severe acute pancreatitis (SAP) complicated with respiratory failure [pancreatitis-associated lung injury (PALI)].

PATIENTS AND METHODS

This study included 30 patients with SAP and 39 patients with PALI. Blood samples were taken from SAP and PALI patients on presenting to the hospital (day 1), and days 2, 3, 5, and 10. The relationship between blood concentrations of the studied endothelial mediators and lung function tests was analyzed.

RESULTS

PALI patients had significantly higher ES, ICAM-1, TF, and vWF blood levels than those with SAP as early as at admission and throughout the period studied. We found the highest concentration of ES on the second day, ICAM-1 and TF at admission, and vWF level on the fifth day. There were adverse correlations between ES, ICAM-1, TF, vWF concentrations, and the index of oxygenation--PaO2/FiO2 ratio (Rs=-0.385, Rs=-0.523, Rs=-0.505, Rs=-0.408, P<0.001, respectively). The most accurate prediction of PALI was provided by ICAM-1 and TF levels on the day of admission [areas under curve (AUCs): ES, 0.704; ICAM-1, 0.787; TF, 0.757; and vWF, 0.686].

CONCLUSION

Endothelium-related mediators ES, ICAM-1, TF, and vWF appear to participate in pancreatitis-associated lung injury. In SAP, the measurement of endothelial mediator levels (especially ICAM-1 and TF) may be used as an early prognostic indicator that would predict the development of respiratory failure and to monitor the severity of lung dysfunction.

Endocan, a putative endothelial cell marker, is elevated in preeclampsia, decreased in acute pyelonephritis, and unchanged in other obstetrical syndromes

Objective: Endocan, a dermatan sulphate proteoglycan produced by endothelial cells, is considered a biomarker for endothelial cell activation/dysfunction. Preeclampsia is characterized by systemic vascular inflammation, and endothelial cell activation/dysfunction. Therefore, the objectives of this study were to determine whether: (1) plasma endocan concentrations in preeclampsia differ from those in uncomplicated pregnancies; (2) changes in plasma endocan concentration relate to the severity of preeclampsia, and whether these changes are specific or observed in other obstetrical syndromes such as small-for-gestational age (SGA), fetal death (FD), preterm labor (PTL) or preterm prelabor rupture of membranes (PROM); (3) a correlation exists between plasma concentration of endocan and angiogenic (placental growth factor or PlGF)/anti-angiogenic factors (soluble vascular endothelial growth factor receptor or sVEGFR-1, and soluble endoglin or sEng) among pregnancies complicated by preeclampsia; and (4) plasma endocan concentrations in patients with preeclampsia and acute pyelonephritis (both conditions in which there is endothelial cell activation) differ.

Method: This cross-sectional study included the following groups: (1) uncomplicated pregnancy (n = 130); (2) preeclampsia (n = 102); (3) pregnant women without preeclampsia who delivered an SGA neonate (n = 51); (4) FD (n = 49); (5) acute pyelonephritis (AP; n = 35); (6) spontaneous PTL (n = 75); and (7) preterm PROM (n = 64). Plasma endocan concentrations were determined in all groups, and PIGF, sEng and VEGFR-1 plasma concentrations were measured by ELISA in the preeclampsia group.

Results: (1) Women with preeclampsia had a significantly higher median plasma endocan concentration than those with uncomplicated pregnancies (p = 0.004); (2) among women with preeclampsia, the median plasma endocan concentration did not differ significantly according to disease severity (p = 0.1), abnormal uterine artery Doppler velocimetry (p = 0.7) or whether diagnosis was made before or after 34 weeks gestational age (p = 0.3); (3) plasma endocan concentration in women with preeclampsia correlated positively with plasma anti-angiogenic factor concentrations [sVEGFR-1: Spearman rho 0.34, p = 0.001 and sEng: Spearman rho 0.30, p = 0.003]; (4) pregnancies complicated by acute pyelonephritis with bacteremia had a lower median plasma endocan concentration than pregnancies complicated by acute pyelonephritis without bacteremia (p = 0.004), as well as uncomplicated pregnancies (p = 0.001); and (5) there was no significant difference in the median plasma endocan concentration between uncomplicated pregnancies and those complicated by FD, delivery of an SGA neonate, PTL or preterm PROM (other members of the “great obstetrical syndromes”; each p > 0.05).

Conclusion: Median maternal plasma endocan concentrations were higher preeclampsia and lower in acute pyelonephritis with bacteremia than in uncomplicated pregnancy. No significant difference was observed in the median plasma endocan concentration between other great obstetrical syndromes and uncomplicated pregnancies. The difference in the direction of change of endocan in preeclampsia and acute pyelonephritis with bacteremia may be consistent with the view that both disease entities differ in pathogenic mechanisms, despite their associations with systemic vascular inflammation and endothelial cell activation/dysfunction.

Using in vivo zebrafish models to understand the biochemical basis of neutrophilic respiratory disease

Neutrophilic inflammation in the lung protects against infectious disease, and usually resolves spontaneously after removal of the inflammatory stimulus. However, much lung disease is caused by a failure of resolution of neutrophilic inflammation. Our laboratory is seeking an understanding of the biochemical basis of inflammation resolution, using the zebrafish model system. Zebrafish larvae are transparent, allowing visualization of GFP (green fluorescent protein)-labelled leucocytes during inflammation in vivo, and they can be readily manipulated by a range of forward and reverse genetic techniques. This combination of advantages makes zebrafish a powerful tool for the study of in vivo inflammatory processes. Using this model, we have visualized the process of inflammation resolution in vivo, and identified a role for apoptosis in this process. In addition, we have performed a forward genetic screen for mutants with defective resolution of inflammation, and reverse genetic experiments examining the influence of candidate genes on inflammation resolution. We have established a platform for screening for compounds with anti-inflammatory activity, which has yielded a number of interesting leads. Looking forward to succeed in the future, we are working at combining mutants, transgenes and pharmacological agents to dissect the biochemical basis of inflammation resolution, and to identify compounds that might be used to treat patients with respiratory disease.

EFFECT OF ARGININE ON CELLULAR ADHESION MOLECULE EXPRESSION AND LEUKOCYTE TRANSMIGRATION IN ENDOTHELIAL CELLS STIMULATED BY BIOLOGICAL FLUID FROM SURGICAL PATIENTS

This study investigated the effect of different arginine (Arg) concentrations on adhesion molecule expression on endothelial cells (ECs) and leukocytes and the transendothelial migration of polymorphonuclear neutrophils (PMNs) through ECs stimulated by plasma or peritoneal drain fluid (PDF) from surgical patients. Human umbilical vein ECs (HUVECs) and PMNs from healthy subjects were treated with different concentrations (0, 50, 100, and 1000 micromol/L) of Arg for 24 h. After that, HUVECs were stimulated for 3 h with plasma or PDF from patients who underwent abdominal surgery, and PMNs were allowed to transmigrate through ECs for 2 h. The HUVEC expression of cellular adhesion molecules (CAMs) and integrin (CD11b) and the interleukin (IL) 8 receptor expression on PMNs were measured by flow cytometry. The PMNs transmigrating through ECs were also analyzed. The results showed that CAM and integrin expressions in PDF groups were higher than those in control groups. Among the PDF groups, IL-8 secretions from ECs and PMNs were lower with 100 and 1000 micromol/L Arg than with 0 and 50 micromol/L Arg, and this was consistent with the expression of the IL-8 receptor on PMNs. In addition, CAM expressions on ECs and CD11b expression on PMNs, as well as PMN transmigration, were lower with 100 and 1000 micromol/L Arg than with 0 and 50 micromol/L Arg. The HUVECs stimulated by plasma from surgical patients had similar effects on surface molecule expression as PDF; however, as shown in PDF stimulation, the effects were not so obvious. Inhibition of nitric oxide production results in high CAM and IL-8 expressions comparable with groups with low Arg administration. The results of this in vitro study suggest that ECs and PMNs were activated after patients' plasma or PDF stimulation. A low Arg concentration comparable with catabolic conditions resulted in higher adhesion molecule expression and greater transendothelial migration of neutrophils. Arginine administration at levels similar to or higher than physiological concentrations reduced IL-8 and CAM expression, and PMN transmigration was also decreased after stimulation with plasma or PDF from surgical patients. Inactivation of NO results in high CAM and IL-8 expression. This finding indicated that NO may be an important endogenous inhibitor for EC-PMN interaction and neutrophil transmigration.

Effect of dietary fish oil supplementation on cellular adhesion molecule expression and tissue myeloperoxidase activity in diabetic mice with sepsis

This study investigated the effect ofn-3 fatty acids on adhesion molecules and tissue myeloperoxidase (MPO) activity in diabetic mice with sepsis. Diabetes was induced by a streptozotocin injection. Mice with blood glucose levels exceeding 2000 mg/l were considered diabetic. Diabetic mice were assigned to two groups with a medium-fat (10 %, w/w) diet either provided by soyabean oil (SO,n30) or fish oil (FO,n30).n-3 fatty acids provided 4·3 % of the total energy and then-3/n-6 fatty acid ratio was 1:2 in the FO diet. After feeding the respective diet for 3 weeks, all mice had sepsis induced by caecal ligation and puncture (CLP) and were killed at 0, 6 or 24 h after CLP, with ten mice at each time-point. The result showed that compared with the SO group, FO group had lower PGE2and TNF-α levels in peritoneal lavage fluid after CLP. Lymphocyte CD11a/CD18 expressions were higher at 6 h, whereas the percentage was lower at 24 h in the SO group than in the FO group. Neutrophil CD11b/CD18 expressions were significantly higher in the SO group than in the FO group at 0 h. The FO group had lower organ MPO activities at various time-points after CLP when compared with those of the SO group. The present findings suggest that compared with the diabetic mice fed SO, a low-dosen-3 fatty acid supplementation may attenuate leucocyte adhesion and infiltration into tissues in diabetic mice complicated with sepsis.

EFFECT OF GLUTAMINE ON CELLULAR ADHESION MOLECULE EXPRESSION AND LEUKOCYTE TRANSMIGRATION IN ENDOTHELIAL CELLS STIMULATED BY PLASMA OR PERITONEAL DRAIN FLUID FROM A SURGICAL PATIENT

This study investigated the effect of glutamine (GLN) concentration on surface molecule expression on endothelial cells (ECs) and leukocytes and the transendothelial migration of polymorphonuclear neutrophils (PMNs) through ECs stimulated by plasma or peritoneal drain fluid (PDF) from a surgical patient. Human umbilical vein ECs (HUVECs) and PMNs from normal subjects were treated with different concentrations (0, 300, 600, and 1000 micromol/L) of GLN for 24 h. After that, HUVECs were stimulated for 3 h with plasma or PDF from a patient who had undergone abdominal surgery, and PMNs were allowed to transmigrate through ECs for 2 h. HUVEC surface expression of cell adhesion molecules and integrin (CD11b) and interleukin (IL) 8 receptor expression on PMNs were measured by flow cytometry. PMNs transmigrating through ECs were also analyzed. The results showed that cell adhesion molecule and integrin expressions in PDF groups were higher than those in control groups. Among the PDF groups, cellular adhesion molecule expressions on ECs and CD11b expression on PMNs were lower with 600 and 1000 micromol/L than with 300 micromol/L GLN. IL-8 secretions from ECs and PMNs were higher with 300 and 600 micromol/L than with 1000 micromol/L GLN, and this was consistent with the expression of the IL-8 receptor on PMNs. PMN transmigration was significantly higher with 300 micromol/L GLN than with the other GLN concentrations. HUVECs stimulated by plasma from surgical patient had the similar effects on surface molecule expression as PDF; however, the influences were not so obvious as shown in PDF stimulation. The results of this in vitro study suggest that ECs and PMNs were activated after patient's plasma or PDF stimulation. A low GLN concentration comparable to catabolic conditions resulted in higher adhesion molecule expression and greater transendothelial migration of neutrophils. GLN administration at levels similar to or higher than physiological concentrations reduced IL-8 and adhesion molecule expression, and PMN transmigration was also decreased after stimulation with plasma or PDF from a surgical patient.

Sepsis: emerging role of nitric oxide and selectins

Sepsis--a state of systemic bacterial infection--often leads to multiorgan failure and is associated with high mortality despite the recent advances achieved in intensive care treatment. Many of the ill effects of sepsis are attributed to an abnormally enhanced host inflammatory response that leads to neutrophil recruitment and activation involving selectins, a class of adhesion molecules, in the initial stages. Nitric oxide and its various isoforms have also been implicated in various vascular alterations and directly participate in the cellular toxicity in sepsis. This review briefly describes the role of selectins and nitric oxide in experimental and clinical sepsis as well as the therapeutic outcomes of blocking therapies.

Toll-IL-1 Receptor Domain-Containing Adaptor Protein Is Critical for Early Lung Immune Responses against Escherichia coli Lipopolysaccharide and Viable Escherichia coli

Pulmonary bacterial diseases are a leading cause of mortality in the U.S. Innate immune response is vital for bacterial clearance from the lung, and TLRs play a critical role in this process. Toll-IL-1R domain-containing adaptor protein (TIRAP) is a key molecule in the TLR4 and 2 signaling. Despite its potential importance, the role of TIRAP-mediated signaling in lung responses has not been examined. Our goals were to determine the role of TIRAP-dependent signaling in the induction of lung innate immune responses against Escherichia coli LPS and viable E. coli, and in lung defense against E. coli in mice. LPS-induced neutrophil sequestration; NF-kappaB translocation; keratinocyte cell-derived chemokine, MIP-2, TNF-alpha, and IL-6 expression; histopathology; and VCAM-1 and ICAM-1 expression were abolished in the lungs of TIRAP-/- mice. A cell-permeable TIRAP blocking peptide attenuated LPS-induced lung responses. Furthermore, immune responses in the lungs of TIRAP-/- mice were attenuated against E. coli compared with TIRAP+/+ mice. TIRAP-/- mice also had early mortality, higher bacterial burden in the lungs, and more bacterial dissemination following E. coli inoculation. Moreover, we used human alveolar macrophages to examine the role of TIRAP signaling in the human system. The TIRAP blocking peptide abolished LPS-induced TNF-alpha, IL-6, and IL-8 expression in alveolar macrophages, whereas it attenuated E. coli-induced expression of these cytokines and chemokines. Taken together, this is the first study illustrating the crucial role of TIRAP in the generation of an effective early immune response against E. coli LPS and viable E. coli, and in lung defense against a bacterial pathogen.

Effect of glutamine on cell adhesion molecule expression and leukocyte transmigration in endothelial cells stimulated by preeclamptic plasma

OBJECTIVE

This study analyzed plasma glutamine (GLN) concentrations in women with preeclampsia. Also, in an in vitro study we evaluated whether GLN concentration was related to surface molecule expressions on endothelial cells (ECs) and polymorphonuclear neutrophils (PMNs) and the transendothelial migration of PMNs through ECs stimulated by preeclamptic plasma.

METHODS

Blood samples were collected from 20 women with preeclampsia and 15 normal pregnant women for plasma GLN analysis. In the in vitro study, human umbilical vein endothelial cells and PMNs were treated with different concentrations (0, 300, 500, and 1000 microM) of GLN for 24 h. After that, we stimulated human umbilical vein endothelial cells for 3 h with plasma from patients with preeclampsia, and PMNs were allowed to transmigrate through ECs for 2 h. EC surface expressions of cellular adhesion molecules (CAMs) and integrin (CD11b) interleukin-8 (IL-8) receptor expressions on PMNs were measured by flow cytometry. The transendothelial migration of PMNs through ECs was also analyzed.

RESULTS

Women with preeclampsia exhibited significantly lower plasma GLN concentrations than did normal pregnant women. The in vitro study showed that, compared with normal plasma, CAM expressions on human umbilical vein endothelial cells and PMNs were increased when preeclamptic plasma was stimulated. Among the groups with preeclamptic plasma stimulation, intracellular CAM-1 expression on ECs and CD11b and IL-8 receptor expressions on PMNs were lower with 500 and 1000 microM than with 300 microM of GLN. IL-8 production from ECs and PMNs was also lower with 500 and 1000 microM than with 300 microM of GLN. PMN transmigration was significantly higher with 300 microM of GLN than with the other GLN concentrations.

CONCLUSIONS

Plasma GLN is depleted in women with preeclampsia. The result of this in vitro study showed that ECs and PMNs were activated after preeclamptic plasma stimulation. A low GLN concentration resulted in greater CAM expression and greater transendothelial migration of neutrophils. GLN administration at levels similar to or higher than physiologic concentrations decreased IL-8 and CAM expressions, and PMN transmigration decreased after stimulation with preeclamptic plasma.

Leukocyte Recruitment to Peritoneal Cavity of Rats Following Formalin Injection: Role of Tachykinin Receptors

The aim of this work was to verify whether formalin would induce leukocyte recruitment following intraperitoneal (i.p.) injection in rats. Formalin (1.25 - 2.5%) induced cell recruitment, which was concentration- and time-dependent (0 - 24 h). Two peaks of leukocyte recruitment were observed. The first peak (from 2 to 4 h) was characterized by a mixed polymorphonuclear and lymphocyte cell population (representing an increase of 100 - 220% and 55 - 60%, respectively), whereas the second peak was characterized by a marked increase in lymphocytes at 24 h (representing an increase of 230%). Pretreatment of animals with specific antagonists for neurokinin NK(1), NK(2), and NK(3) receptors (SR140333, SR48968, and SR142801 compounds, respectively) reduced the early leukocyte increase (representing a significant reduction of 65%, 51%, and 46%, respectively), whereas only the treatment with NK(2)-specific antagonist reduced the late cell increase induced by formalin injection (amounting to a significant reduction of 48%). These results suggested that substance P, neurokinin A, and neurokinin B release accounted for formalin-induced cell migratory activity. The anti-inflammatory drug dexamethasone also reduced cell recruitment, which was mainly related to a reduction in 79% of the neutrophils at 4 h following 1.25% formalin injection, suggesting also a release of lipid mediators (eicosanoids and/or platelet-activating factor) and/or cytokines/chemokines by the formalin injection.

Involvement of inferior turbinate mucosa in chronic sinusitis--localization of T-cell subset

BACKGROUND

In chronic sinusitis (CS), different subsets of leukocytes are involved in development of persistent inflammation of the nasal mucosa. The localization and differentiation of these infiltrating lymphocytes may help us to understand the inflammatory interactions in the epithelium, lamina propria, and seromucous glands of the nasal mucosa in CS.

METHODS

We examined frozen sections of inferior turbinates from 14 patients with nonallergic CS and 10 normal nonallergic controls. We used the avidin-biotin-peroxidase (ABC) technique with monoclonal antibodies against CD3 (total T cells), CD4 (T-helper/inducer cells), CD8 (T-suppressor/cytotoxic cells), CD22 (B cells), CD56 (natural killer cells), elastase (neutrophil granulocytes), eosinophil cationic protein (eosinophil granulocytes), and CD68 (macrophages).

RESULTS

We found significant increases (P < 0.05) of CD3, CD4, and CD8 T cells and B cells in the nasal mucosa of patients with CS. The number of CD68 cells and eosinophils showed no significant rise.

CONCLUSIONS

The different types of leukocytes play a key role in the defense of the respiratory tract. The analysis of the distribution of cells in the epithelium, mucosa, and glands of the inferior turbinate confirmed that nonallergic CS is, in fact, chronic, bacterial rhinosinusitis involving the inferior turbinates, and that the pathomechanism is therefore different from that of nasal polyposis.

Cytotoxicity of stimulated equine neutrophils on equine endothelial cells in culture

We studied the interactions of isolated equine neutrophils with endothelial cells in culture, mimicking a situation of acute inflammation. Our main purpose was to demonstrate that the supernatant of activated neutrophils was sufficient to damage endothelial cells. Equine endothelial cells (from carotid arteries) were covered either with increased numbers of equine neutrophils stimulated by phorbol myristate acetate, or with the supernatant collected after an in vitro stimulation of the neutrophils. Cytotoxicity was estimated by the release of preincorporated 51Cr, and by light microscopy observations. To assert the specific role of reactive oxygen species, endothelial cells were treated by the hypoxanthine/xanthine oxidase (X/XOx) system (production of superoxide anion and hydrogen peroxide), and by hypochlorite (product of the activity of myeloperoxidase). A strong cytotoxicity was found with stimulated neutrophils; microscopic observations indicated a loss of 50% of the endothelial cells and morphological alterations in the remaining cells. The supernatant of stimulated neutrophils was cytotoxic, in correlation with the number of neutrophils used to obtain the supernatant, and with the supernatant concentration of myeloperoxidase. The cytotoxicity of the X/XOx system was weak, but was increased by myeloperoxidase. Hypochlorite was highly toxic. We concluded that the supernatant of stimulated neutrophils was sufficient to obtain cytotoxic effects on the endothelium, in the absence of a direct contact between endothelium and neutrophils, and that this cytotoxicity was mainly linked to the activity of myeloperoxidase. From these in vitro results, it can be extrapolated that in pathologies characterised by an important activation of neutrophils, damage can spread to cells and tissues away from the inflammation focus.

Inhibition of CD11-CD18 complex prevents acute lung injury and reduces mortality after peritonitis in rabbits

Acute lung injury is frequent after severe peritonitis. The aim of this study was to investigate whether inhibition of the adhesion molecule CD11-CD18 on polymorphonuclear leukocytes (PMNs) would have any beneficial effects on pulmonary function and mortality in an animal model reproducing these clinical conditions. Acute peritonitis was induced in 36 rabbits by intraperitoneal injection of zymosan (0.6 g/kg) suspended in mineral oil; 20 were pretreated with a murine-specific IgG2a anti-CD18 monoclonal antibody, 16 (controls) with nonspecific purified murine IgG (1 mg/kg). The animals were followed for 10 d, then killed for histologic examination of the lungs. Blood samples were taken on Days 0, 1, 3, 7, and 10 for red blood cell (RBC), white blood cell (WBC), and platelet counts, pH, PO(2), PCO(2), carbon dioxide content (HCO(3)(-)) measurements, and renal and liver tests. Treatment with the anti-CD18 monoclonal antibody reduced mortality by approximately 40% (p < 0.05). PO(2) was higher in these treated animals than in the control animals throughout the study (p < 0.05 on Day 1, 3, and 10). On Day 1 control animals had significant leukopenia, whereas anti-CD18-treated animals had a moderate increase of the number of circulating WBC compared with baseline values (p < 0.05 between groups). The lungs of the anti-CD18-treated animals showed minor signs of inflammation and PMN infiltration whereas controls had interstitial and intra-alveolar edema and a large number of granulocytes. Quantification of PMNs by morphometry showed that there were constantly less granulocytes in the lungs of the animals treated with the anti-CD18 antibody (p < 0.001). PMN infiltration correlated with the levels of PO(2) (p < 0.001). Lung tissue of anti-CD18-treated rabbits contained less malonyldialdehyde, a by-product of membrane lipid peroxidation by PMN oxygen radicals (950 +/- 120 versus 1,710 +/- 450 pM/mg of protein) and, conversely, more of the antioxidant alpha-tocopherol (136 +/- 22 versus 40 +/- 9 ng/mg of protein), than the control rabbits (p < 0.01). In this particular model of ARDS the monoclonal antibody against the CD11-CD18 complex had a beneficial effect, reducing PMN infiltration and oxygen radical release in the lungs, preventing alveolocapillary membrane damage, improving gas exchange and, finally, significantly reducing mortality.

Changes of the hemostatic network in critically ill patients--is there a difference between sepsis, trauma, and neurosurgery patients?

OBJECTIVE

To study the time course of coagulation data in intensive care patients.

DESIGN

Prospective, descriptive study.

SETTING

Clinical investigation on a surgical and neurosurgical intensive care unit of a university hospital.

PATIENTS

Fifteen patients with severe trauma (injury severity score, 15 to 25), 15 sepsis patients secondary to major surgery, and 15 neurosurgery patients (cancer surgery) were studied.

INTERVENTIONS

Standardized intensive care therapy.

MEASUREMENTS AND MAIN RESULTS

Standard coagulation data and molecular markers of coagulation activation and fibrinolytic activity (soluble thrombomodulin, protein C, free protein S, thrombin/antithrombin III complex, plasmin-alpha 2-antiplasmin complex, tissue plasminogen activator, platelet factor 4, beta-thromboglobulin were measured from arterial blood samples on the day of admission to the intensive care unit (trauma/neurosurgery patients) or on the day of diagnosis of sepsis (baseline value) and serially during the next 5 days. Antithrombin III, fibrinogen, and platelet counts were highest in neurosurgery patients but without significant differences between sepsis and trauma patients. Thrombin/antithrombin III complex increased in the sepsis patients (from 22.6+/-4.2 microg/L to 39.9+/-6.8 microg/L), but decreased in trauma (from 40.2+/-5.1 microg/L to 17.6+/-4.0 microg/L) and neurosurgery patients (from 28.2+/-4.2 microg/L to 16.2+/-3.8 microg/L). Tissue plasminogen activator increased in the sepsis patients (from 14.4+/-3.9 microg/L to 20.7+/-3.8 microg/mL) and remained almost unchanged in the other two groups. Soluble thrombomodulin plasma concentration increased significantly in the sepsis group (max, 131.8+/-22.5 ng/mL), while it remained elevated in the trauma (max, 75.5+/-5.9 ng/mL) and was almost normal in the neurosurgery patients. Protein C and free protein S remained decreased only in the sepsis group.

CONCLUSIONS

Alterations of the hemostatic network were seen in all three groups of critically ill patients. Hemostasis normalized in the neurosurgery patients and posttraumatic hypercoagulability recovered within the study period. By contrast, monitoring of molecular markers of the coagulation process demonstrated abnormal hemostasis in the sepsis patients during the entire study period indicating ongoing coagulation disorders and abnormalities in fibrinolysis in these patients.

Lipoteichoic Acid inhibits Lipopolysaccharide-Induced Adhesion Molecule Expression and IL-8 Release in Human Lung Microvascular Endothelial Cells

Cell adhesion molecule expression (CAM) and IL-8 release in lung microvascular endothelium facilitate neutrophil accumulation in the lung. This study investigated the effects of lipoteichoic acid (LTA), a cell wall component of Gram-positive bacteria, alone and with LPS or TNF-α, on CAM expression and IL-8 release in human lung microvascular endothelial cells (HLMVEC). The concentration-dependent effects of Staphylococcus aureus (S. aureus) LTA (0.3–30 μg/ml) on ICAM-1 and E-selectin expression and IL-8 release were bell shaped. Streptococcus pyogenes (S. pyogenes) LTA had no effect on CAM expression, but caused a concentration-dependent increase in IL-8 release. S. aureus and S. pyogenes LTA (30 μg/ml) abolished LPS-induced CAM expression, and S. aureus LTA reduced LPS-induced IL-8 release. In contrast, the effects of S. aureus LTA with TNF-α on CAM expression and IL-8 release were additive. Inhibitory effects of LTA were not due to decreased HLMVEC viability, as assessed by ethidium homodimer-1 uptake. Changes in neutrophil adhesion to HLMVEC paralleled changes in CAM expression. Using RT-PCR to assess mRNA levels, S. aureus LTA (3 μg/ml) caused a protein synthesis-dependent reduction (75%) in LPS-induced IL-8 mRNA and decreased the IL-8 mRNA half-life from &gt;6 h with LPS to ∼2 h. These results suggest that mechanisms exist to prevent excessive endothelial cell activation in the presence of high concentrations of bacterial products. However, inhibition of HLMVEC CAM expression and IL-8 release ultimately may contribute to decreased neutrophil accumulation, persistence of bacteria in the lung, and increased severity of infection.

Role of cytokines and adhesion molecules in ischemia and reperfusion in patients with acute myocardial infarction

Although acute myocardial infarction (AMI) may involve both plaque rupture and ischemia-reperfusion injury, the pathogenesis of these phenomena is unclear. To elucidate the pathogenesis of AMI, serial measurements of platelet activating factor (PAF), interleukin-6 and cell adhesion molecules were made in patients with AMI. The PAF levels were measured upon hospital admission and at 24 and 72h in 8 patients with AMI. Serum levels of interleukin-6, soluble E-selectin (sE-selectin), soluble intercellular adhesion molecule-1 and soluble vascular cell adhesion molecule- 1 (sVCAM- 1) were measured upon admission and at 24 h and 4 weeks in 30 patients with AMI and 15 patients with stable effort angina. PAF levels were higher in patients with AMI than in normal volunteers; the increased levels lasting at least 72h. In contrast, interleukin-6 increased at 24h. sE-selectin was elevated at admission and sVCAM-1 increased later. sE-selectin levels upon admission in patients with additional ST-segment elevation after reperfusion were significantly higher than those in patients without ST-elevation. In patients with AMI, the time-course of changes in blood levels of cytokines varied according to the individual substances. Although it is unclear what is the precise role of each of the cytokines in the pathophysiology of AMI, sE-selectin may be possibly related to the reperfusion injury in the infarcted myocardium.

Adhesive interaction between P-selectin and sialyl Lewis(x) plays an important role in recurrent coronary arterial thrombosis in dogs

Cell adhesion molecules may play an important role in the disease process of acute coronary syndromes. We have shown a neutralizing anti-P-selectin monoclonal antibody and a sialyl Lewis(x)-containing oligosaccharide (SLe(x)-OS), an analogue of selectin ligand on leukocytes, reduce cyclic flow variations (CFVs) in a canine model of recurrent coronary arterial thrombosis, suggesting the important interaction between P-selectin and SLex for the pathophysiology of these syndromes. However, the functional role of these adhesion molecules in the thrombotic process remains unclear. Therefore, we investigated effects of SLe(x)-OS on CFVs, platelet P-selectin expression, and morphology of the stenotic site in the same model. Anesthetized open-chest dogs (n=34) were randomly divided into 4 groups after developing CFVs. Dogs intravenously received saline or graded doses of SLe(x)-OS (5, 20, or 40 mg/kg bolus) infusion followed by a continuous infusion (5 mg. kg-1. h-1) for 60 minutes. By flow cytometric analysis, P-selectin expression on platelets after CFVs was significantly upregulated during CFVs. Immunohistochemical analysis revealed the incorporation of platelets with upregulated P-selectin within thrombi at the stenotic site. Microscopic observations revealed the presence of numerous platelets adhered to leukocytes at the stenotic site on the damaged endothelium. SLe(x)-OS significantly reduced CFVs, inhibited the P-selectin expression on platelets, and prevented the adherence of platelets and leukocytes. These findings further support the notion that the adhesive interaction between P-selectin on platelets and SLe(x) on leukocytes plays an important role in platelet-mediated thrombus formation in this model.

Endothelial injuries of coronary arteries distal to thrombotic sites: role of adhesive interaction between endothelial P-selectin and leukocyte sialyl LewisX

Intracoronary thrombus formation is associated with epicardial vasoconstriction distal to the thrombotic site. To investigate the mechanisms of abnormal vasomotor function of the artery distal to the thrombotic site, we studied coronary vessels in dogs with cyclic flow variations (CFVs) of the left anterior descending coronary artery (LAD) stenosis with endothelial injury. Coronary rings isolated from the LAD (proximal, stenotic, and distal sites) and control circumflex coronary arteries were tested for responsiveness to endothelium-dependent (acetylcholine and A23187) and endothelium-independent vasodilators (NaNO2). Endothelium-independent relaxation was intact in all 4 sites. Endothelium-dependent relaxation was intact in the control and proximal sites and impaired in the stenotic sites. Relaxations not only to acetylcholine and A23187 but also to serotonin, ADP, and thrombin were impaired in the distal sites after observing CFVs for 80 minutes. Electron microscopy revealed the loss of endothelial integrity with leukocyte adherence to the endothelium in the distal sites. Immunohistochemical expression of P-selectin on the endothelial cells was more upregulated in the distal site than in the proximal site, and P-selectin mRNA expression was significantly greater in the ischemic region distal to the thrombotic site than in the proximal nonischemic region. PB1.3, a neutralizing monoclonal antibody against P-selectin, and sialyl LewisX (SLeX)-containing oligosaccharide SLeX, a carbohydrate analogue of selectin ligand, preserved endothelial function without affecting CFVs. SLeX-containing oligosaccharide preserved endothelial integrity of the distal site and inhibited P-selectin expression of the distal site. Thus, the adhesive interaction between endothelial P-selectin and leukocyte SLeX may play an important role in endothelial injuries of the coronary artery distal to the thrombotic site.

Current understanding of chemokine involvement in allograft transplantation

Multiple studies have demonstrated that chemokines play an essential role in regulating and co-ordinating the infiltration of leucocytes into allografts. Chemokines are expressed in skin, liver, heart, and kidney allografts following initial engraftment, ischemic injury, viral infection, and acute and chronic rejection. To date, most of our understanding of chemokine biology has been generated from studies of animal models of transplantation and little is known about the role of chemokines in human allograft rejection. Chemokines may play important mechanistic roles in transplant rejection, in the development of graft arteriosclerosis, and in chronic sclerosing cholangiopathy. Furthermore, these molecules may serve as sensitive diagnostic indicators for the analysis of rejection, including chronic rejection or other forms of graft dysfunction. Lastly, it is possible that chemokine-targeted therapy might become a feasible option for the treatment of allograft rejection.

Lipocortin 1 and chemokine modulation of granulocyte and monocyte accumulation in experimental inflammation

1. Migration of blood-derived leukocytes to tissue sites of inflammation is a hallmark of the response that the host organizes to counteract an insult or a trauma or an infection. A cascade of events is then activated to allow interaction between the leukocyte and the endothelium of postcapillary venule, and this cascade is finely regulated such that mechanisms of negative control are operating side by side with pathways that promote and sustain the extravasation process. Examples of both these positive and negative regulatory systems are discussed here. 2. In vivo accumulation of specific subtypes of leukocytes in response to application of selective chemokines operates through an indirect mechanism that includes the perivenular mast cell and, in particular, the mast cell-derived amines, such as histamine and serotonin. In fact, treatments of animals with (1) histamine H1 or serotonin antagonists or with (2) the mast cell stabilizer cromolyn or with (3) prior depletion of intact mast cells are maneuvers that successfully reduce eosinophil, neutrophil and monocyte extravasation in response to eotaxin, interleukin-8 or monocyte chemoattractant protein-1, respectively. A model in which histamine provides a P-selectin-dependent rolling phenomenon is then postulated. 3. The discovery that neutrophil-derived lipocortin 1 acts as an autocrine mediator with an inhibitory action on the emigration (diapedesis) process confirms the growing body of experimental data that showed that exogenously administered lipocortin 1 and lipocortin 1 mimetics (peptide Ac2-26) potently inhibit neutrophil extravasation in response to different stimuli. Externalization of lipocortin 1 on the plasma membrane of adherent neutrophils reduces their rate of passage through the endothelial gaps. Because cell-associated lipocortin 1 levels are under the partial control of corticosterone (endogenous circulating glucocorticoid hormone in rodents) and dexamethasone (a synthetic glucocorticoid hormone with a potent anti-inflammatory profile), a model is proposed in which a balance between anti-inflammatory (lipocortin 1, etc.) and pro-inflammatory (adhesion molecules, cytokines and chemokines) mediators explains the difference in the rate of leukocyte accumulation during the different stages of the host inflammatory response. 4. In conclusion, this review emphasizes the importance of in vivo experimental systems as a valid way of obtaining pertinent observations and reiterates the importance of negative regulatory mechanisms on the leukocyte extravasation process operating within the host.

A CD18/ICAM-1-dependent pathway mediates eosinophil adhesion to human bronchial epithelial cells

Eosinophil adhesion to airway epithelium is believed to facilitate eosinophil accumulation and retention in asthmatic airways. Monoclonal antibodies (mAb) against intercellular adhesion molecule-1 (ICAM-1) and its CD18 leukocyte integrin ligands have been shown to inhibit airway eosinophilia in animal models of asthma, although the role of this pathway in eosinophil-epithelial adhesion is not fully understood. To investigate the role in vitro of CD18 and ICAM-1, we measured adhesion of fluorescently labeled human eosinophils to normal human bronchial epithelial cell (NHBEC) monolayers pretreated for 24 h with culture medium (low constitutive ICAM-1) or tumor necrosis factor-alpha (TNF-alpha; 1 ng/ml) and interferon-gamma (IFN-gamma) (10 ng/ml; increased ICAM-1). Stimulation of eosinophils with C5a (10(-7) M) increased adhesion measured at 30 min to unactivated NHBEC from 11.4 +/- 0.7 to 15.5 +/- 0.4% (n = 4), and this increase was CD18/ICAM-1-independent, whereas phorbolmyristate acetate (PMA) (10(-8) M)-induced adhesion (20.7 +/- 1.7%) was abolished by anti-CD18 and reduced by anti-ICAM-1. In contrast, C5a- and PMA-induced adhesion to TNF-alpha/IFN-gamma-activated NHBEC (increased from 11.1 +/- 1.3% to 21.9 +/- 1.0% and 27.6 +/- 1.9%, respectively) was CD18- and ICAM-1-dependent. Eotaxin, but not regulated on activation normal T cells expressed and secreted, macrophage inflammatory protein-1, formyl methionyl leucyl phenylalanine, leukotriene B4 or platelet-activating factor, also induced CD18/ICAM-1-dependent adhesion to activated NHBEC. In the absence of added chemoattractants, eosinophil adhesion to NHBEC increased with time and, at 120 min, was significantly greater (P < 0.01) to activated NHBEC (37.3 +/- 2.4%, n = 5) than to unactivated monolayers (24.3 +/- 1.9%); mAb against CD18 or ICAM-1 abolished increased, but not basal, adhesion. These results suggest that CD18/ICAM-1 mediated eosinophil adhesion to activated NHBEC but that adhesion to resting NHBEC was largely independent of this pathway.

Cyclo-oxygenase-2 regulates inducible ICAM-1 and VCAM-1 expression in human vascular smooth muscle cells

Prostaglandins are well characterised inflammatory mediators, whose formation is regulated by constitutive (COX-1) or inducible (COX-2) isoforms of cyclo-oxygenase. We have previously demonstrated that IL-1 beta causes an induction of COX-2 in human vascular smooth muscle (1). This present study investigates the ability of different cytokines to induce ICAM-1 and VCAM-1 on human vascular smooth muscle, and tests whether co-induced COX-2 would regulate their expression. IL-1 beta induced ICAM-1, and COX activity, while it had no affect on VCAM-1. Conversely, IL-4 induced VCAM-1, while it had no effect on PGE2 release or ICAM-1 expression. Inhibition of IL-1 beta induced COX-2 and elevated ICAM-1 expression, an effect reversed by exogenous PGE2. Furthermore, IL-1 beta inhibited IL-4 induced VCAM-1 expression, which was also reversed by COX-2 inhibition. These results demonstrate that COX-2 limits adhesion molecule expression on human vascular smooth muscle cells and suggest that COX-2 can play a protective role in cardiovascular and inflammatory diseases.

Selective inhibition of TNF-alpha induced cell adhesion molecule gene expression by tanapox virus

Poxviruses encode virulence factors that have been identified as proteins that are secreted from infected host cells. Some of these secretory proteins impede host immune defences. We have previously demonstrated that tanapox virus (TPV) infected cells secrete an early 38 kDa glycopeptide that binds to human (h) interferon-gamma, hIL-2, and hIL-5. We now show an additional activity in the supernatant from TPV infected cells that down-regulates the expression of tumour necrosis factor-alpha (TNF-alpha) induced cell adhesion molecule gene expression. This activity was not detected in mock infected cells. Enzyme linked immunosorbent assays (ELISA) on primary human endothelial cells, show the induction of E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) following TNF-alpha or IL-1 beta treatment, as expected. Supernatant from TPV infected cells significantly decreased the TNF-alpha but not IL-1 beta-induced expression of these molecules. Mobility shift assays and Northern blot analyses further show that the supernatant from TPV infected cells inhibited TNF-alpha-induced activation of the nuclear transcription factor-kappa B (NF-kappa B) and transcriptional activation of the E-selectin, VCAM-1 and ICAM-1 genes. Based on TNF-alpha affinity chromatography, this activity appears to be associated with a 38 kDa glycopeptide.

Interleukin-4 and lipopolysaccharide synergize to induce vascular cell adhesion molecule-1 expression in human lung microvascular endothelial cells

Recent studies suggest that increased vascular cell adhesion molecule-1 (VCAM-1) expression on vascular endothelium in bronchial mucosa biopsies correlates with interleukin-4 (IL-4) levels in bronchiolar lavage fluid of allergic asthmatics. The severity of asthma in patients allergic to house dust mite has also been shown to correlate with lipopolysaccharide (LPS), rather than allergen, concentration in dust. We hypothesized that to induce effective VCAM-1 expression in human lung microvascular endothelial cells (HLMVEC), IL-4 may require the presence of a co-stimulus such as LPS. To test this hypothesis we measured, by enzyme-linked immunosorbent assay, induction of cell adhesion molecule expression on, and human eosinophil adhesion to, cultured HLMVEC monolayers pretreated with IL-4 alone or combined with LPS. IL-4 synergized with LPS to induce VCAM-1 expression at 24, 48, or 72 h, whereas IL-4 alone induced expression at 72 h only. IL-4 did not induce expression of intercellular adhesion molecule-1 or E-selectin or alter LPS-induced expression of either. Pre-exposure of HLMVEC to LPS or IL-4 (1 h), followed by IL-4 or LPS, respectively (23 h), also induced VCAM-1 expression. Eosinophil adhesion to HLMVEC monolayers treated with IL-4 and LPS together, but not alone, significantly (P < 0.001) increased from 9.6 +/- 1.5% (control) to 26.9 +/- 3.3% and was inhibited by a monoclonal antibody against the VCAM-1 ligand, very late antigen-4. Analysis of VCAM-1 mRNA revealed synergism between IL-4 and LPS which may, in part, contribute to enhanced VCAM-1 expression. These results suggest that the presence of a co-stimulus such as LPS may be necessary for IL-4 to effectively induce VCAM-1 expression in lung microvasculature.

Identification of an endothelial cell-specific regulatory region in the murine endothelin-1 gene

Endothelin-1 is a 21-amino acid peptide first characterized as a potent vasoactive compound synthesized by endothelial cells. Because of its high level cell-restricted pattern of expression, we have employed this gene as a model for investigating the DNA and protein elements that mediate endothelial cell-specific gene expression. In this study we have identified a complex positive regulatory region located at base pairs -364 to -320 in the murine endothelin-1 gene. This region consists of three functionally dependent elements, ETE-C, ETE-D, and ETE-E, which are all required for full activity. When a 43-base pair fragment containing these three elements was employed in heterologous promoter experiments, this sequence was capable of increasing transcriptional activity in an endothelial cell-specific fashion. None of the elements contains a recognized consensus sequence known to bind transcriptional regulatory proteins in higher eukaryotes; however, each element does appear to mediate protein binding. The combination of all three elements promotes binding of a protein complex that is endothelial cell-specific. This is the first evidence for an endothelial cell-specific DNA regulatory element and cognate binding proteins.

Interactions of lymphocytes from patients with psoriatic arthritis or healthy controls and cultured endothelial cells

Psoriatic arthritis (PA) is an inflammatory rheumatic disease that can concomitantly occur in patients with psoriasis vulgaris. Psoriatic synovitis shows alterations of the synovial microvasculature. Inflammatory cells adhere to endothelial cells (EC) and migrate through the vascular wall of postcapillary venules located in the subintimal layer of the synovial membrane. The aim of our study was to investigate, first, the phenotype of lymphocytes (LC) of PA patients using flow cytometry (FC) with regard to activation antigens and adhesion molecules; second, the adhesion of LC of PA patients on cultivated resting or activated (with thrombin, LPS, IFN-gamma, or TNF-alpha) human umbilical vein endothelial cells (HUVEC) by counting the Feulgen-stained nuclei of both adherent LC and HUVEC using image analysis; and third, the synthesis of IL-6 and IL-8 in both LC and HUVEC 24 hr after cell contact. These cytokines were determined qualitatively by immunofluorescence and quantitatively at the single-cell level by FC as well as in the supernatants of the cultures using commercial cytokine ELISAs. Fourth, we investigated whether or not the LC adhesion on HUVEC as well as the cytokine production could be inhibited by monoclonal antibodies against LC- or EC-specific adhesion molecules. In contrast to controls PA patients showed an increased surface expression of CD11a, b, and c as well as of CD44 but a reduced surface expression of CD49d/CD29, and CD49e/CD29, and cell-bound fibronectin on CD3+ LC. The activation markers CD25 and HLA-DR were found to be slightly enhanced in PA. The cell adhesion was generally enhanced in PA patients vs controls. It could be reduced with monoclonal antibodies (MoAbs) against CD11a and CD18 on IFN-gamma- or TNF-alpha-activated HUVEC but was generally enhanced after treatment of HUVEC with MoAbs against CD54, CD62E, or CD106. Due to LC adhesion on HUVEC IL-6 and IL-8 were produced in significantly higher amounts in PA patients compared to controls. This effect occurred already in resting but was enhanced in activated HUVEC. While IL-6 is mainly produced by HUVEC but also in smaller quantities by LC, IL-8 is synthesized only by HUVEC and could be modified by preincubation with MoAbs against LC- or EC-specific adhesion molecules in parallel to the cell adhesion. The experiments show that the main adhesion pathway in LC homing of PA patients is the interaction of the LC adhesion molecule CD11a/CD18 with CD54 on EC followed by an enhanced synthesis of proinflammatory and chemotactic cytokines. These results favor the hypothesis that the pathological alterations of the microvasculature in PA patients are generated by altered homing processes.

Chronic allograft failure: the clinical problem

Long-term survival statistics for organ allografts have not improved substantially over time, despite improved immunosuppression and organ preservation and better surgical and perioperative management. Chronic rejection is the most important long-term limitation in allografts and increasingly seems to be caused by a multifactorial series of antigen-dependent and antigen-independent factors. Early injury is critical to late events, whether antigen driven (early acute rejection episodes and human leukocyte antigen mismatching) or antigen independent (ischemia/reperfusion injury and brain death). Ongoing alloimmunologic injury to the host and inadequate organ mass functioning (donor age, gender, race, and organ size) also seem to be important to this persisting process. Associated recipient conditions, which includes hypertension and hyperlipidemia, and postoperative complications, which include drug nephrotoxicity and infections, may affect this late-phase graft loss. These deleterious risk factors for chronic rejection of long-functioning allografts are an important subject for future investigation.

Complement activates neutrophils during PTCA procedure in patients with unstable angina pectoris

We estimated adherence, aggregation and chemiluminescence of neutrophils as well as concentrations of C3c, C4 and C5 complement components and complement haemolytic activity (CH50) in 27 patients with unstable angina pectoris subjected to percutaneous transluminal coronary angioplasty (PTCA). The control group consisted of 12 patients with unstable angina pectoris, in whom coronary angiography was performed but PTCA was decided against for various reasons. Blood samples for examination were taken from coronary sinus and peripheral vein just before, 1 min and 20 min after PTCA or coronary angiography. We observed enhancement of neutrophil adherence, aggregation and chemiluminescence, and decrease in concentrations of C3c, C5 and complement haemolytic activity (CH50) after PTCA procedure. In conclusion we think that ischemia resulting from PTCA causes complement activation in an alternative pathway which seems to be connected with neutrophil activation.

Does age influence circulating adhesion molecules in the critically ill?

OBJECTIVE

Soluble adhesion molecules are regarded to be markers of inflammation, endothelial activation, or damage. The influence of age on plasma concentrations of circulating adhesion molecules should be serially studied in critically ill intensive care patients.

DESIGN

Prospective and descriptive study over 5 days.

SETTING

Clinical investigation in a surgical intensive care unit of a university hospital.

PATIENTS

Thirty critically ill patients (Acute Physiology and Chronic Health Evaluation [APACHE] II score of > 15 points), with sepsis secondary to postoperative complications, were included in this study. Fifteen consecutive patients aged < 50 yrs and 15 consecutive patients aged > 70 yrs were prospectively studied.

INTERVENTIONS

All patients were treated by the standard protocols of our intensive care unit, which did not differ between the groups. The patients received continuous analgesia-sedation and mechanical ventilation. Intensivists caring for the patients were not involved in the study and were blinded to data analysis.

MEASUREMENTS AND MAIN RESULTS

Hemodynamic parameters were extensively monitored in all patients. From arterial blood samples, plasma concentrations of soluble adhesion molecules (endothelial leukocyte adhesion molecule-1, intercellular adhesion molecule-1, vascular cell adhesion molecule-1, granule membrane protein-140) were measured on the day of admission (i.e., baseline values) and during the following 5 days. Three of the younger patients and six of the elderly patients died during the study period (p < .05). Oxygen delivery and consumption, and the other hemodynamic data, were without group differences throughout the study. Plasma concentrations of all adhesion molecules were beyond normal at baseline in both groups. These concentrations increased further during the first 2 to 3 days in both groups, with a significantly higher increase in the elderly patients (endothelial leukocyte adhesion molecule-1 to 179 +/- 32 ng/mL; intercellular adhesion molecule-1 to 1695 +/- 158 ng/mL; vascular cell adhesion molecule-1 to 1395 +/- 212 ng/mL; and granule membrane protein-140 to 888 +/- 119 ng/mL). In the younger patients, concentrations of soluble adhesion molecules decreased later in the study and almost reached baseline values on day 5. In the elderly patients, these concentrations remained significantly higher until the end of the study.

CONCLUSIONS

The higher plasma concentrations of the measured adhesion molecules in elderly critically ill patients indicate that elderly patients are more prone than younger patients to a more pronounced activation or even damage of the endothelium. Further work needs to be done to determine the prognostic importance and to define the role of soluble adhesion molecules, particularly in the elderly critically ill patient.

Elevated selectin levels after severe trauma: a marker for sepsis and organ failure and a potential target for immunomodulatory therapy

Severe injury is frequently complicated by sepsis and organ failure. Activated neutrophils adherent to inflamed endothelia have been implicated in the pathogenesis of these complications. Identification of high-risk patients to target immunomodulatory therapy, however, remains an elusive goal. We postulated that (1) patients at risk for sepsis and organ failure could be identified by measuring shed selectin adhesions molecules as a marker of endothelial activation after injury and reperfusion, and (2) these elevated selectin levels would correlate with injury severity, shock, major complications, and mortality.

METHODS

Blood samples were drawn from 50 patients with multiple trauma every 2 hours after admission for the first 24 hours, and every 6 hours for the subsequent 24 hours, and assayed for levels of shed E- and P-selectin. Patients were then stratified according to Injury Severity Score (ISS), presence or absence of shock, presence or absence of organ failure and/or infectious complications, and finally, death versus survival.

RESULTS

Trauma patients who had ISS < 30, who did not develop shock, sepsis, or organ dysfunction, had minimal increase in circulating E- and P-selectin over admission levels. In patients who subsequently developed infectious complications, organ dysfunction, or both, or subsequently went on to die, elevated levels of E-selectin levels were evident by 36 hours, and in some cases, earlier. Differences between nonsurvivors and survivors was statistically significant. There was also a trend toward increased levels of P-selectin in the same group of patients, although these differences were not significant. There was no differentiation in either of the two selections when patients were stratified according to ISS or presence of shock.

CONCLUSION

A subset of major trauma patients manifest increased levels of circulating E-selectin adhesion molecules after resuscitation. These patients seem to be at increased risk of death and possibly at risk for infections complications and organ failure. Selectin blockade is a potential new immunomodulatory strategy in this subgroup of patients.

The influence of volume therapy and pentoxifylline infusion on circulating adhesion molecules in trauma patients

Adhesion molecules appear to play a pivotal role in tissue damage secondary to the inflammatory process. Besides neutrophil- and endothelial-bound adhesion molecules, soluble forms have been detected in the circulating blood. They seem to be good markers of endothelial damage, but they may also have other biological functions. Plasma concentrations of soluble adhesion molecules (endothelial leucocyte adhesion molecules (sELAM-1), intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), and granule membrane protein 140 (sGMP-140) were serially measured over 5 days by enzyme-linked immunosorbent assays (ELISA) in 45 consecutive trauma patients. These received, by random allocation, only either hydroxyethylstarch solution 10% (mean molecular weight 200,000 daltons) (n = 15) or human albumin 20% (n = 15) for volume therapy. Another 15 patients without defined volume therapy received pentoxifylline continuously (1.2 mg.kg-1.h-1). Measurements were carried out on the day of admission to the intensive care unit (baseline) and during the next 5 days. At baseline, plasma concentrations of all adhesion molecules were similar in all groups. In the hydroxyethyl starch group, sELAM-1 and sICAM-1 concentrations decreased significantly (p < 0.05) reaching normal values during the study period whereas the mean (SD) values increased in the pentoxifylline group (sELAM-1: 71.1 (16.7) to 91.6 (17.8) ng.ml-1) and the albumin group (sICAM-1: 400 (81) to 749 (101) ng.ml-1) (p < 0.05). sVCAM-1 increased outside the normal range only in the human albumin group (to 760 +/- 69 ng.ml-1) (p < 0.05). sGMP-140 plasma concentration increased only in those receiving albumin (432 (85) to 550 (93) ng.ml-1) and this was significantly different to the other groups (p < 0.05). None of the other haemodynamic or laboratory factors could be correlated with plasma concentrations of the adhesion molecules. We conclude that volume therapy with hydroxyethyl starch resulted in a decrease in circulating adhesion molecules in our trauma patients. In contrast, volume therapy with albumin did not exert this effect. Continuous infusion of pentoxifylline did not have a beneficial modulating action on circulating adhesion molecules.

Influence of long-term continuous intravenous administration of pentoxifylline on endothelial-related coagulation in critically ill patients

OBJECTIVE

To determine the influence of pentoxifylline on endothelial-associated coagulation.

DESIGN

Prospective, randomized, placebo-controlled study.

SETTING

A surgical intensive care unit of a university hospital.

PATIENTS

Consecutive patients (n = 60) with trauma or sepsis secondary to major (nontrauma) surgery. All patients received controlled mechanical ventilation.

INTERVENTIONS

According to a randomized sequence, the patients either received pentoxifylline continuously over 5 days (1.5 mg/kg/hr iv) (trauma-pentoxifylline group [n = 15], sepsis-pentoxifylline group [n=15] or saline solution as placebo (trauma-control group [n = 15], sepsis-control group [n = 15].

MEASUREMENTS AND MAIN RESULTS

In addition to the standard coagulation screen, thrombomodulin, protein C, (free) protein S, and thrombin-antithrombin plasma concentrations were measured by enzyme-linked immunosorbent assays. Intensive care therapy, hemodynamics, and changes of Acute Physiology and Chronic Health Evaluation II score were comparable for pentoxifylline-treated and nontreated patients. An average dose of 2.5 g/day of pentoxifylline (range 2.2 to 2.9) was infused into the pentoxifylline-treated patients. At baseline, plasma thrombomodulin concentrations were higher in the septic patients than in the trauma patients. Thrombomodulin plasma concentrations increased significantly more in the control patients (trauma: from 38.9 +/- 10.5 to 59.9 +/- 10.1 ng/mL; sepsis: from 49.7 +/- 12.1 to 72.3 +/- 11.2 ng/mL) than in the pentoxifylline-treated patients (trauma: from 37.9 +/- 11.9 to 50.2 +/- 9.2 ng/mL; sepsis from 51.9 +/- 10.1 to 63.3 +/- 10.2). Starting from similar baseline values, protein C concentration increased significantly more in the sepsis-pentoxifylline patients (from 52.0 +/- 11.1% to 69.1 +/- 11.1%) than in the untreated septic patients (from 50.1 +/- 10.0% to 52.5 +/- 9.5%). There were no significant differences between the pentoxifylline-treated and nontreated groups for protein S and thrombin-antithrombin concentrations. Standard coagulation parameters (fibrinogen, activated partial thromboplastin time, antithrombin III) did not differ between these groups either.

CONCLUSIONS

Continuous intravenous administration of pentoxifylline for 5 days beneficially influenced the thrombomodulin/protein C/protein S system in both the trauma and septic patients.

The effects of pentoxifylline on circulating adhesion molecules in critically ill patients with acute renal failure treated by continuous veno-venous hemofiltration

OBJECTIVE

Circulating adhesion molecules appear to be excellent markers of endothelial activation in critically ill patients. Pentoxifylline (PTX) may limit sequelae of inflammation and subsequent endothelial activation by various mechanisms. The influence of PTX on the plasma levels of soluble adhesion molecules in critically ill patients undergoing continuous veno-venous hemofiltration (CVVH) was studied.

DESIGN

Prospective, randomized, blinded study.

SETTING

Clinical investigation in the surgical intensive care unit of a university hospital.

PATIENTS AND PARTICIPANTS

Fourteen consecutive patients suffering from acute renal failure (ARF) with postoperative complications who received continuous pentoxifylline (CVVH-PTX) i.v. were compared with 14 patients with ARF who did not receive PTX (CVVH control group).

INTERVENTIONS

Pump-driven CVVH was carried out with a blood flow ranging from 120 to 150 ml/min. All patients received fentanyl and midazolam continuously and were on mechanical ventilation. PTX (300 mg) was given as a loading dose, followed by continuous infusion of 1.2 mg/kg per h for the next 5 days.

MEASUREMENTS AND RESULTS

From arterial blood samples, plasma levels of soluble adhesion molecules (endothelial leukocyte adhesion molecules [sELAM-1], and intercellular adhesion molecule-1 [sICAM-1], vascular cell adhesion molecule-1 [sVCAM-1], and P-selectin granule membrane protein [sGMP-140] were measured using enzyme-linked immuno-sorbent assays (ELISA). Measurements were carried out before the start of CVVH to establish baseline values and continued during the next 5 days.

MAIN RESULTS

Eleven of the CVVH-PTX patients and 8 of the CVVH control patients survived during the investigation period. In the CVVH-PTX patients 2.4 +/- 0.3 g/day of PTX was given. At baseline, plasma levels of sELAM-1, sICAM-1, and sVCAM-1 were markedly higher than normal in both groups. In the CVVH control patients, all measured soluble adhesion molecules increased further during the study period (sELAM-1 from 90 +/- 22 to 134 +/- 30 ng/ml; sICAM-1 from 958 +/- 173 to 1460 +/- 209 ng/ml; sVCAM-1 from 1100 +/- 188 to 1804 ng/ml; sGM-140 from 499 +/- 102 to 688 +/- 121 ng/ml) (p < 0.05), whereas in the PTX-treated CVVH patients, plasma levels of all soluble adhesion molecules remained almost unchanged. The PaO2/FIO2 increased in the PTX-treated patients (from 209 +/- 67 to 282 +/- 58 mmHg) and remained almost unchanged in the CVVH control patients.

CONCLUSION

Leukocyte/endothelial interactions play an important role in the inflammatory process. Circulating adhesion molecules may serve as markers of the extent of inflammation. Continuous i.v. administration of PTX was successful in blunting the increase of soluble adhesion molecules in critically ill patients undergoing CVVH. Whether these effects result from improved circulation at the microcirculatory level or from (direct or indirect) beneficial effects on endothelial cells warrants further controlled studies.