Cyclophilin A is a ligand for RAGE in thrombo-inflammation

AIMS

Cyclophilin A (CyPA) induces leucocyte recruitment and platelet activation upon release into the extracellular space. Extracellular CyPA therefore plays a critical role in immuno-inflammatory responses in tissue injury and thrombosis upon platelet activation. To date, CD147 (EMMPRIN) has been described as the primary receptor mediating extracellular effects of CyPA in platelets and leucocytes. The receptor for advanced glycation end products (RAGE) shares inflammatory and prothrombotic properties and has also been found to have similar ligands as CD147. In this study, we investigated the role of RAGE as a previously unknown interaction partner for CyPA.

METHODS AND RESULTS

Confocal imaging, proximity ligation, co-immunoprecipitation, and atomic force microscopy were performed and demonstrated an interaction of CyPA with RAGE on the cell surface. Static and dynamic cell adhesion and chemotaxis assays towards extracellular CyPA using human leucocytes and leucocytes from RAGE-deficient Ager-/- mice were conducted. Inhibition of RAGE abrogated CyPA-induced effects on leucocyte adhesion and chemotaxis in vitro. Accordingly, Ager-/- mice showed reduced leucocyte recruitment and endothelial adhesion towards CyPA in vivo. In wild-type mice, we observed a downregulation of RAGE on leucocytes when endogenous extracellular CyPA was reduced. We furthermore evaluated the role of RAGE for platelet activation and thrombus formation upon CyPA stimulation. CyPA-induced activation of platelets was found to be dependent on RAGE, as inhibition of RAGE, as well as platelets from Ager-/- mice showed a diminished activation and thrombus formation upon CyPA stimulation. CyPA-induced signalling through RAGE was found to involve central signalling pathways including the adaptor protein MyD88, intracellular Ca2+ signalling, and NF-κB activation.

CONCLUSION

We propose RAGE as a hitherto unknown receptor for CyPA mediating leucocyte as well as platelet activation. The CyPA-RAGE interaction thus represents a novel mechanism in thrombo-inflammation.

Long-Term Microvascular Changes in Multisystem Inflammatory Syndrome in Children

This case-control study investigates changes in microcirculation and endothelial function in the acute phase of multisystem inflammatory syndrome in children and 3 to 6 months after onset.

Association between inflammation, glycocalyx biomarkers, and endothelial function in children with hypercholesterolemia

INTRODUCTION

Hypercholesterolemia is a risk factor for premature arteriosclerosis. Inflammation and oxidative stress are thought to contribute to endothelial dysfunction preceding vasculopathy. We investigated the association between inflammation, glycocalyx biomarkers, endothelial function and vascular parameters in children with hypercholesterolemia.

METHODS

In 22 patients (LDL-cholesterol > 130 mg/dl; median age [IQR]: 13 [2.3] years) and 22 controls (13 [2.5] years) tumor necrosis factor-alpha (TNF-α), oxidized cholesterol (oxLDL), and glycocalyx biomarkers (Syndecan-1, Hyaluronan) were measured using immunoassays. Endothelial function was assessed by peripheral arterial tonometry, sublingual glycocalyx and microcirculation by videomicroscopy and carotid intima media thickness by ultrasound.

RESULTS

OxLDL was significantly higher in patients (78.9 [38.2] vs. 50.3 [16.6] U/l, p=0.002), whereas all other experimental parameters were comparable between groups. Multivariate analysis revealed a significant association of Syndecan-1 with TNF-α (β=0.75, p<0.001) and with hypercholesterolemia (β=0.31, p=0.030). The interaction term combining TNF-α and hypercholesterolemia showed a significant effect (p=0.034). Sex was an independent predictor of endothelial function.

CONCLUSION

The combined effect of hypercholesterolemia and inflammation on glycocalyx perturbation and the impact of sex in the premature development of arteriosclerosis deserve further evaluation. Therapeutic approaches tackling low grade systemic inflammation-may offer potential to prevent or delay progression of CVD and cardiovascular complications.  .

Case Report: Stüve-Wiedemann syndrome-a rare cause of persistent pulmonary hypertension of the newborn

Introduction

Persistent pulmonary hypertension of the newborn (PPHN) is a life-threatening condition characterized by hypoxemia due to elevated pulmonary vascular resistance. PPHN commonly arises secondary to various underlying conditions, including infection, meconium aspiration, and respiratory distress syndrome. Management includes pulmonary vasodilators, mechanical ventilation, oxygen supplementation, vasopressors, and volume replacement. Stüve-Wiedemann syndrome (SWS), a rare genetic disorder characterized by bone dysplasia, respiratory distress, hyperthermia, and swallowing difficulties, may present with pulmonary hypertension, indicating a poor prognosis.

Case description

A term female neonate presented with secondary respiratory failure and severe PPHN of unknown etiology on the second day of life, necessitating intubation. Clinical findings included facial dysmorphia, camptodactyly, skeletal anomalies, and generalized muscular hypotonia. High-frequency oscillation ventilation and surfactant administration yielded marginal improvement. On the third day of life, a severe pulmonary hypertensive crisis necessitated inhaled and systemic pulmonary vasodilators along with volume and catecholamine therapy. Whole exome sequencing revealed a homozygous mutation in the leukemia inhibitory factor receptor (LIFR) gene, consistent with Stüve-Wiedemann syndrome.

Discussion/conclusion

The case underscores the importance of considering and prompting evaluation of rare genetic causes in the differential diagnosis of PPHN, especially when other abnormalities are present and conventional therapies prove inadequate. Therapeutic strategies must account for the different pathophysiology of primary PPHN including vascular remodeling, as seen in SWS, which may not respond to pulmonary vasodilators typically employed in secondary PPHN due to vasoconstriction. In this case, the patient responded well to treatment for primary PPHN, but the use of high-frequency oscillation ventilation and surfactant was not helpful.

A20 and the noncanonical NF-κB pathway are key regulators of neutrophil recruitment during fetal ontogeny

Newborns are at high risk of developing neonatal sepsis, particularly if born prematurely. This has been linked to divergent requirements the immune system has to fulfill during intrauterine compared with extrauterine life. By transcriptomic analysis of fetal and adult neutrophils, we shed new light on the molecular mechanisms of neutrophil maturation and functional adaption during fetal ontogeny. We identified an accumulation of differentially regulated genes within the noncanonical NF-κB signaling pathway accompanied by constitutive nuclear localization of RelB and increased surface expression of TNF receptor type II in fetal neutrophils, as well as elevated levels of lymphotoxin α in fetal serum. Furthermore, we found strong upregulation of the negative inflammatory regulator A20 (Tnfaip3) in fetal neutrophils, which was accompanied by pronounced downregulation of the canonical NF-κB pathway. Functionally, overexpressing A20 in Hoxb8 cells led to reduced adhesion of these neutrophil-like cells in a flow chamber system. Conversely, mice with a neutrophil-specific A20 deletion displayed increased inflammation in vivo. Taken together, we have uncovered constitutive activation of the noncanonical NF-κB pathway with concomitant upregulation of A20 in fetal neutrophils. This offers perfect adaption of neutrophil function during intrauterine fetal life but also restricts appropriate immune responses particularly in prematurely born infants.

Noninvasive Ventilation in Preterm Infants: Factors Influencing Weaning Decisions and the Role of the Silverman-Andersen Score

The factors influencing weaning of preterm infants from noninvasive ventilation (NIV) are poorly defined and the weaning decisions are often driven by subjective judgement rather than objective measures. To standardize quantification of respiratory effort, the Silverman-Andersen Score (SAS) was included in our nursing routine. We investigated the factors that steer the weaning process and whether the inclusion of the SAS would lead to more stringent weaning. Following SAS implementation, we prospectively evaluated 33 neonates born ≤ 32 + 0 weeks gestational age. Age-, weight- and sex-matched infants born before routine SAS evaluation served as historic control. In 173 of 575 patient days, NIV was not weaned despite little respiratory distress (SAS ≤ 2), mainly due to bradycardias (60% of days without weaning), occurring alone (40%) or in combination with other factors such as apnea/desaturations. In addition, “soft factors” that are harder to grasp impact on weaning decisions, whereas the SAS overall played a minor role. Consequently, ventilation times did not differ between the groups. In conclusion, NIV weaning is influenced by various factors that override the absence of respiratory distress limiting the predictive value of the SAS. An awareness of the factors that influence weaning decisions is important as prolonged use of NIV has been associated with adverse outcome. Guidelines are necessary to standardize NIV weaning practice.

Kawasaki disease and increased cardiovascular risk: Is there a link to circulating glycocalyx biomarkers?

AIMS

Kawasaki disease (KD) is an acute systemic vasculitis with possible long-term impact of general cardio-vascular health. An endothelial glycocalyx disorder during the disease's acute phase might predispose to long-term vascular anomalies leading to endothelial dysfunction and atherosclerosis. To investigate any association between increased cardiovascular risk and endothelial glycocalyx, we assessed circulating glycocalyx components in patients with a KD history, and analysed their association with acute-phase clinical features and more importantly, with patients' current cardiovascular risk factors.

METHODS

This prospective observational cohort study included 51 subjects: 31 patients with a history of KD, and 20 healthy subjects matched for age and sex. We analysed serum syndecan-1 and hyaluronan via ELISA. We assessed features reported during the acute phase of KD such as blood counts, C-reactive protein (CRP) levels and coronary artery aneurysms (CAA), and their current blood pressure and lipid markers in relation to measured glycocalyx components.

RESULTS

Our multivariate analysis revealed that hyaluronan and syndecan-1 levels were not associated with KD. However, the latter exhibited a significant association with acute-phase blood count alterations in patients with KD. Furthermore, significant interactions of hyaluronan and syndecan-1 with certain cardiovascular risk factors like blood lipids and blood pressure were only present in KD patients.

CONCLUSION

Vasculitis during KD's acute phase might predispose to a long-term endothelial glycocalyx alteration, influenced by other factors having a vascular impact such as blood pressure and circulating lipids.

CLINICAL TRIAL REGISTRATION

German Clinical Trials Register on 25th February 2016, DRKS00010071 https://www.drks.de/drks_web/.

The Endothelial Glycocalyx: Physiology and Pathology in Neonates, Infants and Children

The endothelial glycocalyx (EG) as part of the endothelial surface layer (ESL) is an important regulator of vascular function and homeostasis, including permeability, vascular tone, leukocyte recruitment and coagulation. Located at the interface between the endothelium and the blood stream, this highly fragile structure is prone to many disruptive factors such as inflammation and oxidative stress. Shedding of the EG has been described in various acute and chronic diseases characterized by endothelial dysfunction and angiopathy, such as sepsis, trauma, diabetes and cardiovascular disease. Circulating EG components including syndecan-1, hyaluronan and heparan sulfate are being evaluated in animal and clinical studies as diagnostic and prognostic markers in several pathologies, and advances in microscopic techniques have enabled in vivo assessment of the EG. While research regarding the EG in adult physiology and pathology has greatly advanced throughout the last decades, our knowledge of the development of the glycocalyx and its involvement in pathological conditions in the pediatric population is limited. Current evidence suggests that the EG is present early during fetal development and plays a critical role in vessel formation and maturation. Like in adults, EG shedding has been demonstrated in acute inflammatory conditions in infants and children and chronic diseases with childhood-onset. However, the underlying mechanisms and their contribution to disease manifestation and progression still need to be established. In the future, the glycocalyx might serve as a marker to identify pediatric patients at risk for vascular sequelae and as a potential target for early interventions.

Cohort profile: the MUNICH Preterm and Term Clinical study (MUNICH-PreTCl), a neonatal birth cohort with focus on prenatal and postnatal determinants of infant and childhood morbidity

PURPOSE

The MUNICH Preterm and Term Clinical (MUNICH-PreTCl) birth cohort was established to uncover pathological processes contributing to infant/childhood morbidity and mortality. We collected comprehensive medical information of healthy and sick newborns and their families, together with infant blood samples for proteomic analysis. MUNICH-PreTCl aims to identify mechanism-based biomarkers in infant health and disease to deliver more precise diagnostic and predictive information for disease prevention. We particularly focused on risk factors for pregnancy complications, family history of genetically influenced health conditions such as diabetes and paediatric long-term health-all to be further monitored and correlated with proteomics data in the future.

PARTICIPANTS

Newborns and their parents were recruited from the Perinatal Center at the LMU University Hospital, Munich, between February 2017 and June 2019. Infants without congenital anomalies, delivered at 23-41 weeks of gestation, were eligible.

FINDINGS

Findings to date concern the clinical data and extensive personal patient information. A total of 662 infants were recruited, 44% were female (36% in preterm, 46% in term). 90% of approached families agreed to participate. Neonates were grouped according to gestational age: extremely preterm (<28 weeks, N=28), very preterm (28 to <32 weeks, N=36), late preterm (32 to <37 weeks, N=97) and term infants (>37+0 weeks, N=501). We collected over 450 data points per child-parent set, (family history, demographics, pregnancy, birth and daily follow-ups throughout hospitalisation) and 841 blood samples longitudinally. The completion rates for medical examinations and blood samples were 100% and 95% for the questionnaire.

FUTURE PLANS

The correlation of large clinical datasets with proteomic phenotypes, together with the use of medical registries, will enable future investigations aiming to decipher mechanisms of disorders in a systems biology perspective.

TRIAL REGISTRATION NUMBER

DRKS (00024189); Pre-results.

Non-invasive evaluation of macro- and microhemodynamic changes during induction of general anesthesia – A prospective observational single-blinded trial

BACKGROUND: Hypotension and bradycardia are known side effects of general anesthesia, while little is known about further macro- and microhemodynamic changes during induction. Intriguing is furthermore, why some patients require no vasopressor medication to uphold mean arterial pressure, while others need vasopressor support. OBJECTIVE: Determination of macro- and microhemodynamic changes during induction of general anesthesia. METHODS: We enrolled 150 female adults scheduled for gynaecological surgery into this prospective observational, single-blinded trial. Besides routinely measuring heart rate (HR) and mean arterial blood pressure (MAP), the non-invasive technique of thoracic electrical bioimpedance was applied to measure cardiac output (CO), cardiac index (CI), stroke volume (SV), stroke volume variability (SVV) and index of myocardial contractility (ICON) before induction of anesthesia, 7 times during induction, and, finally, after surgery in the recovery room. Changes in microcirculation were assessed using sidestream dark field imaging to establish the perfused boundary region (PBR), a validated gauge of glycocalyx health. Comparisons were made with Friedman’s or Wilcoxon test for paired data, and with Mann-Whitney-U test for unpaired data, with post-hoc corrections for multiple measurements by the Holm-Bonferroni method. RESULTS: 83 patients did not need vasopressor support, whereas 67 patients required therapy (norepinephrine, atropine or cafedrine/theodrenaline) to elevate MAP values to ≥70mmHg during induction, 54 of these receiving norepinephrine (NE) alone. Pre-interventional (basal) values of CO, CI, ICON, SV and SVV were all significantly lower in the group of patients later requiring NE (p < 0.04), whereas HR and MAP were identical for both groups. HR, MAP and CO decreased from baseline to 12 min after induction of general anesthesia in both the patients without and those with NE support. Heart rate decreased significantly by about 25% in both groups (–19 to –21 bpm). The median individual decrease of MAP amounted to –26.7% (19.7/33.3, p < 0.001) and –26.1% (11.6/33.2, p < 0.001), respectively, whereas for CO it was –40.7% (34.1/50.1, p < 0.001) and –43.5% (34.8/48.7). While these relative changes did not differ between the two groups, in absolute values there were significantly greater decreases in CO, CI, SV and ICON in the group requiring NE. Noteably, NE did not restore ICON or the other cardiac parameters to levels approaching those of the group without NE. PBR was measured in a total of 84 patients compiled from both groups, there being no intergroup differences. It increased 6.4% (p < 0.001) from pre-induction to the end of the operation, indicative of damage to microvascular glycocalyx. CONCLUSION: Non-invasive determination of CO provides additional hemodynamic information during anesthesia, showing that induction results in a significant decrease not only of MAP but also of CO and other cardiac factors at all timepoints compared to baseline values. The decrease of CO was greater than that of MAP and, in contrast to MAP, did not respond to NE. There was also no sign of a positive inotropic effect of NE in this situation. Support of MAP by NE must consequently result from an increase in peripheral arterial resistance, posing a risk for oxygen supply to tissue. In addition, general anesthesia and the operative stimulus lead to an impairment of the microcirculation.

Effect of gestational age and postnatal age on the endothelial glycocalyx in neonates

Prematurity predisposes to cardiovascular disease; however the underlying mechanisms remain elusive. Disturbance of the endothelial glycocalyx (EG), an important regulator of vessel function, is thought to contribute to vascular pathology. Here, we studied the EG with respect to gestational and postnatal age in preterm and term neonates. The Perfused Boundary Region (PBR), an inverse measure of glycocalyx thickness, was measured postnatally in 85 term and 39 preterm neonates. Preterm neonates were further analyzed in two subgroups i.e., neonates born < 30 weeks gestational age (group A) and neonates born ≥ 30 weeks (group B). In preterm neonates, weekly follow-up measurements were performed if possible. PBR differed significantly between preterm and term neonates with lowest values representing largest EG dimension in extremely premature infants possibly reflecting its importance in fetal vascular development. Linear regression revealed a dependence of PBR on both, gestational age and postnatal age. Furthermore, hematocrit predicted longitudinal PBR changes. PBR measured in group A at a corrected age of > 30 weeks was significantly higher than in group B at birth, pointing towards an alteration of intrinsic maturational effects by extrinsic factors. These changes might contribute to the increased cardiovascular risk associated with extreme prematurity.

Effects of Prematurity on the Cutaneous Microcirculatory Network in the First Weeks of Life

Background: Preterm infants are at increased risk for hypertension in adolescence. Microcirculatory dysfunction has been identified as an underlying cause for cardiovascular disease. Our goal was to document the development of the cutaneous microcirculation in preterm infants during the first weeks of life and to compare it to the situation in term infants at birth. Methods: In 20 preterm infants, microcirculatory parameters were obtained prospectively by Sidestream Dark Field (SDF) Imaging at the upper inner arm once a week until discharge or 37 weeks of gestational age. A single microcirculatory measurement was obtained in 30 term infants during the first 3 days of life. Videos were blinded and analyzed with the AVA software. Results: Microcirculatory parameters in preterm infants differ significantly from term infants with a lower vessel surface (VS), a lower percentage of large and medium but higher percentage of small vessels, a higher Functional Vessel Density (FVD), and a higher Microcirculatory Flow Index (MFI). In multivariable linear regression models we could demonstrate a statistically significant association between the dependent microcirculatory variables (VS, diameter distribution, MFI) and gestational age as independent predictor variable while adjusting for postnatal days of life. Looking at the longitudinal follow-up data of preterm infants by means of a multivariable mixed-effects linear regression model adjusting for clinical variables, there is a significant decrease in FVD with increasing postnatal age, however no other significant changes in microcirculatory parameters over time. Accordingly, comparing the microcirculatory parameters of near term former preterm infants with term born neonates, we could still find significant differences with a higher FVD, lower VS and differences in vessel diameters in the former premature group. Conclusion: Infants born prematurely exhibit distinct microcirculatory alterations compared to term neonates with gestational age at birth being associated with microvascular parameters. Interestingly, this premature vascular phenotype persists even close to corrected term age. In view of the known increased cardiovascular risk of former preterm infants, our observations might have important clinical impact. The factors governing the development of the microvascular network in preterm infants and the contribution of microcirculatory changes observed here to vascular pathology in later life need to be further investigated.

Monitoring of the microcirculation in children undergoing major abdominal and thoracic surgery: A pilot study

BACKGROUND: Monitoring of the macrocirculation during surgery provides limited information on the quality of organ perfusion. OBJECTIVE: We investigated the feasibility of perioperative microcirculatory measurements in children. METHODS: Sublingual microvessels were visualized by handheld videomicroscopy in 11 children (19 mo – 10 yrs) undergoing surgery > 120 min at four time points: T0) after induction of anesthesia; T1) before end of anesthesia, T2) 6 h post surgery and T3) 24 h post surgery. RESULTS: Measurements were feasible in all children at T0 and T1. At T2 and T3, imaging was restricted to 6 and 4 infants, respectively, due to respiratory compromise and missing cooperation. The capillary density was reduced at T1 compared to T0 (8.1 mm/mm2 [4.0-17.0] vs. 10.6 mm/mm2 [5.1-19.3]; p = 0.01), and inversely related to norepinephrine dose (Pearson r = -0.65; p = 0.04). Microvascular flow and serum glycocalyx makers Syndecan-1 and Hyaluronan increased significantly from T0 to T1. CONCLUSION: Perioperative microcirculatory monitoring in children requires a high amount of personal and logistic resources still limiting its routine use. Major surgery is associated with microvascular alterations and glycocalyx perturbation. The possible consequences on patient outcome need further evaluation. Efforts should concentrate on the development of next generation devices designed to facilitate microcirculatory monitoring in children.

Maturation of Platelet Function During Murine Fetal Development In Vivo

OBJECTIVE

Platelet function has been intensively studied in the adult organism. However, little is known about the function and hemostatic capacity of platelets in the developing fetus as suitable in vivo models are lacking.

APPROACH AND RESULTS

To examine fetal platelet function in vivo, we generated a fetal thrombosis model and investigated light/dye-induced thrombus formation by intravital microscopy throughout gestation. We observed that significantly less and unstable thrombi were formed at embryonic day (E) 13.5 compared with E17.5. Flow cytometry revealed significantly lower platelet counts in E13.5 versus E17.5 fetuses versus adult controls. In addition, fetal platelets demonstrated changed activation responses of surface adhesion molecules and reduced P-selectin content and mobilization. Interestingly, we also measured reduced levels of the integrin-activating proteins Kindlin-3, Talin-1, and Rap1 during fetal development. Consistently, fetal platelets demonstrated diminished spreading capacity compared with adults. Transfusion of adult platelets into the fetal circulation led to rapid platelet aggregate formation even in young fetuses. Yet, retrospective data analysis of a neonatal cohort demonstrated no correlation of platelet transfusion with closure of a persistent ductus arteriosus, a process reported to be platelet dependent.

CONCLUSIONS

Taken together, we demonstrate an ontogenetic regulation of platelet function in vivo with physiologically low platelet numbers and hyporeactivity early during fetal development shedding new light on hemostatic function during fetal life.

MST1-dependent vesicle trafficking regulates neutrophil transmigration through the vascular basement membrane

Neutrophils need to penetrate the perivascular basement membrane for successful extravasation into inflamed tissue, but this process is incompletely understood. Recent findings have associated mammalian sterile 20-like kinase 1 (MST1) loss of function with a human primary immunodeficiency disorder, suggesting that MST1 may be involved in immune cell migration. Here, we have shown that MST1 is a critical regulator of neutrophil extravasation during inflammation. Mst1-deficient (Mst1-/-) neutrophils were unable to migrate into inflamed murine cremaster muscle venules, instead persisting between the endothelium and the basement membrane. Mst1-/- neutrophils also failed to extravasate from gastric submucosal vessels in a murine model of Helicobacter pylori infection. Mechanistically, we observed defective translocation of VLA-3, VLA-6, and neutrophil elastase from intracellular vesicles to the surface of Mst1-/- neutrophils, indicating that MST1 is required for this crucial step in neutrophil transmigration. Furthermore, we found that MST1 associates with the Rab27 effector protein synaptotagmin-like protein 1 (JFC1, encoded by Sytl1 in mice), but not Munc13-4, thereby regulating the trafficking of Rab27-positive vesicles to the cellular membrane. Together, these findings highlight a role for MST1 in vesicle trafficking and extravasation in neutrophils, providing an additional mechanistic explanation for the severe immune defect observed in patients with MST1 deficiency.

Sphingosine-1-phosphate receptor 3 promotes leukocyte rolling by mobilizing endothelial P-selectin

Sphingosine-1-phosphate (S1P) participates in inflammation; however, its role in leukocyte rolling is still unclear. Here we use intravital microscopy in inflamed mouse cremaster muscle venules and human endothelial cells to show that S1P contributes to P-selectin-dependent leukocyte rolling through endothelial S1P receptor 3 (S1P₃) and Gα_q, PLCβ and Ca²⁺. Intra-arterial S1P administration increases leukocyte rolling, while S1P₃ deficiency or inhibition dramatically reduces it. Mast cells involved in triggering rolling also release S1P that mobilizes P-selectin through S1P₃. Histamine and epinephrine require S1P₃ for full-scale effect accomplishing it by stimulating sphingosine kinase 1 (Sphk1). In a counter-regulatory manner, S1P₁ inhibits cAMP-stimulated Sphk1 and blocks rolling as observed in endothelial-specific S1P₁^−/− mice. In agreement with a dominant pro-rolling effect of S1P₃, FTY720 inhibits rolling in control and S1P₁^−/− but not in S1P₃^−/− mice. Our findings identify S1P as a direct and indirect contributor to leukocyte rolling and characterize the receptors mediating its action.

The lipid sphingosine-1-phosphate (S1P) is known to mediate leukocyte recruitment in inflammation. Here, Nussbaum et al. show that S1P, via its receptor S1P3, also regulates leukocyte rolling on endothelium by promoting the presentation of the adhesion molecule P-selectin on the endothelial surface.

SDF-1 fused to a fractalkine stalk and a GPI anchor enables functional neovascularization

The facilitated recruitment of vascular progenitor cells (VPCs) to ischemic areas might be a therapeutic target for neovascularization and repair. However, efficient and directed attraction of VPCs remains a major challenge in clinical application. To enhance VPC homing, we developed a fusion protein (S1FG), based on the biology of stroma-derived factor-1/CXCL12 and the mucin backbone taken from fractalkine/CXCL12. A GPI-anchor was included to link the fusion-protein to the cell surface. HUVECs transfected with S1FG were capable of increasing firm adhesion of CXCR4+-mononuclear cells (THP-1) under shear stress conditions in vitro. In an in vivo rabbit model of chronic hind limb ischemia, local S1FG application enhanced the recruitment of adoptively transferred embryonic EPCs (eEPCs) to the ischemic muscles 2.5-fold. S1FG combined with eEPC(low) (2 × 10(6)) yielded similar capillary growth as eEPC(high) (5 × 10(6)) alone. Compared to controls, collateral formation was increased in the S1FG eEPC(low) group, but not the eEPC(high) group without S1FG, whereas perfusion was found enhanced in both groups. In addition, S1FG also increased collateral formation and flow when combined with AMD3100 treatment, to increase circulating levels of endogenous VPC. These data demonstrate that the fusion protein S1FG is capable of enhancing the recruitment of exogenously applied or endogenously mobilized progenitor cells to sites of injury. Recombinant versions of S1FG applied via catheters in combination with progenitor cell mobilization may be useful in the treatment of chronic ischemic syndromes requiring improved perfusion.

Myeloperoxidase: a leukocyte-derived protagonist of inflammation and cardiovascular disease

SIGNIFICANCE

The heme-enzyme myeloperoxidase (MPO) is one of the major neutrophil bactericidal proteins and is stored in large amounts inside azurophilic granules of neutrophils. Upon cell activation, MPO is released and extracellular MPO has been detected in a wide range of acute and chronic inflammatory conditions. Recent ADVANCES AND CRITICAL ISSUES: Apart from its role during infection, MPO has emerged as a critical modulator of inflammation throughout the last decade and is currently discussed in the initiation and propagation of cardiovascular diseases. MPO-derived oxidants (e.g., hypochlorous acid) interfere with various cell functions and contribute to tissue injury. Recent data also suggest that MPO itself exerts proinflammatory properties independent of its catalytic activity. Despite advances in unraveling the complex action of MPO and MPO-derived oxidants, further research is warranted to determine the precise nature and biological role of MPO in inflammation.

FUTURE DIRECTIONS

The identification of MPO as a central player in inflammation renders this enzyme an attractive prognostic biomarker and a potential target for therapeutic interventions. A better understanding of the (patho-) physiology of MPO is essential for the development of successful treatment strategies in acute and chronic inflammatory diseases.

Neutrophil and endothelial adhesive function during human fetal ontogeny

Attenuation of the immune response contributes to the high rate of neonatal infections, particularly in premature infants. Whereas our knowledge of innate immune functions in mature neonates is growing, little is known about the ontogeny of neutrophil recruitment. We investigated neutrophils and ECs in the course of gestation with respect to rolling and adhesive functions. With the use of microflow chambers, we demonstrate that the neutrophil's ability to roll and adhere directly correlates with gestational age. These adhesion-related abilities are very rare in extremely premature infants (<30 weeks of gestation), which may correlate with our observation of markedly reduced expression of PSGL-1 and Mac-1 on neutrophils in preterm infants. In parallel, the capacity of HUVECs to mediate neutrophil adhesion under flow increases with gestational age. In addition, HUVECs from extremely premature infants exerting the lowest ability to recruit adult neutrophils show a diminished up-regulation of E-selectin and ICAM-1. Finally, by following neutrophil function postnatally, we show that maturation of PMN recruitment proceeds equivalently during extra- and intrauterine development. Thus, PMN recruitment and EC adhesion-related functions are ontogenetically regulated in the fetus, which might contribute significantly to the high risk of life-threatening infections in premature infants.

Changes in microcirculation as early markers for infection in preterm infants--an observational prospective study

In adults with severe sepsis, the disturbances of the sublingual microcirculation can be quantified with orthogonal polarization spectral imaging. We investigated the cutaneous microcirculation of preterm infants with proven infection (PosInf) and with suspected but unproven infection (NegInf). In 25 infants, orthogonal polarization spectral images were obtained daily, videos of the images were blinded, and analyzed off-line. Functional small vessel density (FSVD) was prospectively calculated from day 3 to day 30 of life. There were 17 episodes of proven and nine episodes of suspected but unproven nosocomial late onset infection. Four infants remained healthy. The data were analyzed for the 5 d before the start of antibiotics (day -5 until day -1). FSVD varied widely, but in the PosInf-group, we found a 10% decline from day -5 to day -1 (p = 0.013). There was no significant change over time in the NegInf-group (p = 0.58). Thus, in infants with proven infection, FSVD decreases already 1 d before changes in laboratory parameters. However, these changes in FSVD during infection are not represented by absolute values, but must be identified by daily intraindividual observation.

Functional vessel density in the first month of life in preterm neonates

Changes in microcirculation have been recognized as central to many disease processes. The aim of this study was to evaluate factors, which influence the microcirculation of the skin during the first month of life in premature infants. Red blood cell (RBC) velocity, vessel diameter, and functional small vessel density (FSVD) were measured daily for the first 30 d on the upper arm in preterm infants with gestational age <30 wk. Orthogonal polarization spectral (OPS) images were analyzed off-line with the Capi- Scope-Image program. In 25 infants, FSVD decreased significantly from week 1 (mean +/- SD 236 +/- 33 cm/cm2) to week 4 (207 +/- 30 cm/cm2) and correlated directly with Hb levels and incubator temperature. Vessel diameters and RBC velocity did not change significantly, nor did clinical parameters such as blood pressure, heart rate or body temperature. Microvascular parameters were not dependent on gestational or postnatal age. The microcirculation of the skin might be an easily accessible window to obtain better understanding of circulatory changes in the postnatal period. Our data are essential as basis for further studies in this field. Hb levels and possible incubator temperatures have a substantial influence on functional small vessel density and therefore need to be taken in account.

[Treatment recommendations in psychiatric disability insurance expertises: are they helpful]

BACKGROUND

In recent years the total number of people drawing a pension - especially for psychiatric reasons - from Switzerland's Federal Disability Insurance ("IV") has been steadily climbing. As we have revealed in earlier studies of persons applying for a disability pension for psychiatric reasons only 64 % had received psychiatric treatment and only 20 % adequate drug treatment .

HYPOTHESIS

In this study we examined whether, treatment recommendations given by medical experts were followed and if so, how successfully.

METHODS

In 40 patients who had got a psychiatric expertise in 2004 at the Psychiatric Outpatient Department, University of Basel, on behalf of the Swiss Disability Insurance, a 1-year follow-up was done and the results were compared.

RESULTS

At reassessment significantly more patients (58 %) were in psychiatric-psychotherapeutic treatment than at first assessment (32 %). The recommended drug treatments were fully complied with in only 43 % of the cases; the recommended psychotherapy in only 9 % of the cases; and recommended in-patient treatment at a psychiatric hospital in only 14 % of the cases. During the time between evaluations, the seriousness of the condition had altered in a number of cases: in 33 % the condition had noticeably improved (e. g. from severe to mild depression) or was no longer present, and in 9 % the condition had worsened (e. g. from mild to severe depression). No significant relationship was found between compliance (full, partial or no implementation of recommended treatments) and change in illness severity. Partnership has been identified as the factor with the strongest influence on illness severity: in subjects who were married or living with a partner illness course was much better than in subjects without a stable partnership.