Serum soluble E- and L-selectin in the very early neonatal period

Markers of endothelial cell activation in suspected late onset neonatal sepsis in Surinamese newborns: a pilot study

BACKGROUND

Serum levels of markers of endothelial cell activation are associated with bacteremia and mortality in sepsis in adults, children, and newborns with early onset sepsis. We hypothesize that levels of these markers are associated with these outcomes in hospitalized newborns with suspected late onset neonatal sepsis (LONS).

METHODS

In this prospective cohort study, newborns admitted to the tertiary neonatal care facility of Suriname were included upon clinical suspicion of LONS and before start of antibiotic treatment, between April 1, 2015 and May 31, 2016. Serum concentrations of angiopoietin-1, angiopoietin-2, and soluble isoforms of P-selectin, E-selectin, vascular cell adhesion molecule-1 (sVCAM-1), intercellular adhesion molecule-1 (sICAM-1), platelet and endothelial cell adhesion molecule-1 (sPECAM-1), matrix metalloproteinase-9 (MMP-9), neutrophil elastase, and tissue-inhibitor of metalloproteinases-1 (TIMP-1) were measured.

RESULTS

Twenty-thee newborns were included. Baseline characteristics were similar between newborns with and without bacteremia and between non-survivors and survivors. Only soluble E-selectin (sE-selectin) was higher in newborns with bacteremia versus non-bacteremia (P=0.04) and lower in non-survivors (P=0.04). No conclusions could be made for sVCAM-1 due to high serum concentrations.

CONCLUSIONS

In conclusion, the data from this pilot study indicate that serum levels of markers of endothelial cell activation are poorly associated with bacteremia and mortality.

Serum concentrations of endothelial cell adhesion molecules and their shedding enzymes and early onset sepsis in newborns in Suriname

BACKGROUND

Early onset sepsis (EOS) is defined as onset of sepsis within 72 hours after birth. Leucocyte-endothelial interactions play a pivotal part in EOS pathophysiology. Endothelial cell adhesion molecules (CAMs) orchestrate these interactions and their soluble isoforms (sCAMs) are released into the vasculature by enzymes called sheddases.

PURPOSE

This study was undertaken to explore further the pathophysiology of EOS and to investigate the potential of sCAM and their sheddases as potential biomarkers for EOS.

METHODS

Stored serum aliquots were used from 71 Surinamese newborns suspected of EOS and 20 healthy newborns from an earlier study. Serum had been collected within 72 hours after birth and six (8.6%) newborns had a positive blood culture with gram-negative pathogens. Concentrations of sCAMs sP-selectin, sE-selectin, soluble vascular cell adhesion molecule-1, intercellular adhesion molecule-1 and platelet and endothelial cell adhesion molecule-1, sheddases matrix metalloproteinase-9 (MMP-9) and neutrophil elastase (NE) and sheddase antagonist tissue-inhibitor of metalloproteinases-1 (TIMP-1) were measured simultaneously with Luminex and ELISA.

RESULTS

MMP-9 and TIMP-1 levels were measured in serum of n=91 newborns and sCAMs and NE levels in serum of n=80 newborns, respectively. We found no differences in median concentrations of sCAMs, MMP-9 and TIMP-1 or NE between blood culture positive EOS, blood culture negative EOS and control groups at start of antibiotic treatment.

CONCLUSIONS

Our data indicate that serum concentrations of sCAMs and their sheddases have no clinical utility as biomarkers for EOS.

TRIAL REGISTRATION NUMBER

NCT02486783. Results.

Mean platelet volume and uric acid levels in neonatal sepsis

OBJECTIVES

To determine the role of mean platelet volume (MPV) and uric acid levels in the diagnosis of neonatal sepsis (NS).

METHODS

A total of 146 newborns with suspected NS were prospectively included in the study and infants without NS (n = 142) were assigned as controls. The patients were divided into three groups: Group I (n = 64): clinical NS, Group II (n = 82): culture-proven NS, and Group III (n = 142): healthy controls.

RESULTS

The patients in Group II had the highest C-reactive protein (CRP) levels (54.6 ± 5.4 mg/L), lowest platelet counts (199,329 ± 135,952/mm(3)) and lowest uric acid levels (2.6 ± 1.8 mg/dL) when compared to Groups I and III (p < 0.05, for all comparisons). MPV values were higher in Group I (10.6 ± 1.1 fL) and Group II (10.4 ± 0.9 fL) when compared to Group III (9.2 ± 1.2 fL) (p = 0.001), although there was no difference between Groups I and II. Area under curve (AUC) values for CRP, MPV, and uric acid were 0.92 (p = 0.001), 0.76 (p = 0.001) and 0.28 (p = 0.001), respectively. The diagnostic cut-off values for CRP and MPV were 9.5 mg/dL and 10.4 fL. Sensitivity and specificity of MPV in NS were 54 % and 82 % respectively. When combined with CRP its sensitivity and specificity increased to 89 % and 79 % respectively.

CONCLUSIONS

The combined use of CRP and MPV should be considered in the early diagnosis of NS, but uric acid levels may only be utilized as an additional tool to support diagnosis. CRP is shown to be more sensitive and specific than MPV and uric acid in diagnosing neonatal sepsis.

The utility of serial plasma sE-selectin measurements in the prediction of retinopathy of prematurity in premature infants

BACKGROUND

sE-selectin has recently been suggested as a surrogate marker for prediction of ROP development.

AIMS

The possible role of serial plasma sE-selectin measurements in early prediction and diagnosis of ROP was evaluated.

STUDY DESIGN

Prospective observational study

SUBJECTS

Forty six preterm infants aged <34weeks of gestation and weighing <1500 g were enrolled. Of these, 26 constituted the ROP group and 20 constituted the no-ROP group. sE-selectin levels were measured serially in blood samples on the 1st day and on 14th and 28th postnatal days.

OUTCOME MEASURES

The primary outcome measure was to evaluate the role of sE-selectin concentrations in prediction of ROP.

RESULTS

The mean gestational age and birth weight were significantly lower in the ROP group. The mean sE-selectin concentrations in ROP group were significantly greater than those in no-ROP group at each time point (1st, 14th and 28th days of postnatal life). A receiver operating characteristic (ROC) analysis showed that at a plasma concentration of ≥86ng/mL on the 1st postnatal day, sE-selectin had a sensitivity of 100% and a specificity of 94.1% with a positive predictive value of 96.3% and a negative predictive value of 100%. Plasma sE-selectin concentrations were significantly greater in infants who developed ROP in three different time points.

CONCLUSIONS

This study shows for the first time that measurement of plasma sE-selectin concentrations as early as the first day of life might help identify preterm infants at risk of ROP.

Soluble adhesion molecules as markers for sepsis and the potential pathophysiological discrepancy in neonates, children and adults

Sepsis is a severe and life-threatening systemic inflammatory response to infection that affects all populations and age groups. The pathophysiology of sepsis is associated with aberrant interaction between leukocytes and the vascular endothelium. As inflammation progresses, the adhesion molecules that mediate these interactions become shed from cell surfaces and accumulate in the blood as soluble isoforms that are being explored as potential prognostic disease biomarkers. We critically review the studies that have tested the predictive value of soluble adhesion molecules in sepsis pathophysiology with emphasis on age, as well as the underlying mechanisms and potential roles for inflammatory shedding. Five soluble adhesion molecules are associated with sepsis, specifically, E-selectin, L-selectin and P-selectin, intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. While increased levels of these soluble adhesion molecules generally correlate well with the presence of sepsis, their degree of elevation is still poorly predictive of sepsis severity scores, outcome and mortality. Separate analyses of neonates, children and adults demonstrate significant age-dependent discrepancies in both basal and septic levels of circulating soluble adhesion molecules. Additionally, a range of both clinical and experimental studies suggests protective roles for adhesion molecule shedding that raise important questions about whether these should positively or negatively correlate with mortality. In conclusion, while predictive properties of soluble adhesion molecules have been researched intensively, their levels are still poorly predictive of sepsis outcome and mortality. We propose two novel directions for improving clinical utility of soluble adhesion molecules: the combined simultaneous analysis of levels of adhesion molecules and their sheddases; and taking age-related discrepancies into account. Further attention to these issues may provide better understanding of sepsis pathophysiology and increase the usefulness of soluble adhesion molecules as diagnostic and predictive biomarkers.

Effect of notoginsenoside R1 on hepatic microcirculation disturbance induced by gut ischemia and reperfusion

AIM: To assess the effect of notoginsenoside R1 on hepatic microcirculatory disturbance induced by gut ischemia/reperfusion (I/R) in mice.

METHODS: The superior mesenteric artery (SMA) of C57/BL mice was ligated for 15 min to induce gut ischemia followed by 30-min reperfusion. In another set of experiments, R1 was continuously infused (10 mg/kg per hour) from 10 min before I/R until the end of the investigation to study the influence of R1 on hepatic microcirculatory disturbance induced by gut I/R. Hepatic microcirculation was observed by inverted microscopy, and the vascular diameter, red blood cell (RBC) velocity and sinusoid perfusion were estimated. Leukocyte rolling and adhesion were observed under a laser confocal microscope. Thirty and 60 min after reperfusion, lactate dehydrogenase (LDH), alanine aminotransferase (ALT) and aspartate transaminase (AST) in peripheral blood were determined. The expression of adhesion molecules CD11b/CD18 in neutrophils and tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and monocyte chemotactic protein-1 (MCP-1) in plasma were evaluated by flow cytometry. E-selectin and intercellular adhesion molecule-1 (ICAM-1) in hepatic tissue were examined by immunofluorescence.

RESULTS: After gut I/R, the diameters of terminal portal venules and central veins, RBC velocity and the number of perfused sinusoids were decreased, while the leukocyte rolling and adhesion, the expression of E-selectin in hepatic vessels and CD18 in neutrophils, IL-6, MCP-1, LDH, ALT and AST were increased. R1 treatment attenuated these alterations except for IL-6 and MCP-1.

CONCLUSION: R1 prevents I/R-induced hepatic microcirculation disturbance and hepatocyte injury. The effect of R1 is related to its inhibition of leukocyte rolling and adhesion by inhibiting the expression of E-selectin in endothelium and CD18 in neutrophils.

Increased erythrocyte adhesion in mice and humans with hereditary spherocytosis and hereditary elliptocytosis

Mice with disruptions of the red blood cell (RBC) cytoskeleton provide severe hemolytic anemia models in which to study multiorgan thrombosis and infarction. The incidence of cerebral infarction ranges from 70% to 100% in mice with alpha-spectrin deficiency. To determine whether mutant RBCs abnormally bind adhesive vascular components, we measured adhesion of mouse and human RBCs to immobilized human thrombospondin (TSP) and laminin (LM) under controlled flow conditions. Mutant RBCs had at least 10-fold higher adhesion to TSP compared with normal RBCs (P <.006). Mutant relative to unaffected RBC adhesion to LM was significantly (P <.01) increased as well. Treatment of RBCs with the anionic polysaccharide dextran sulfate inhibited mutant RBC adhesion to TSP (P <.001). Treatment of RBCs with antibodies to CD47 or the CD47-binding TSP peptide 4N1K did not inhibit TSP adhesion of RBCs. Previously, we have shown that infarcts in alpha-spectrin-deficient sph/sph mice become histologically evident beginning at 6 weeks of age. TSP adhesion of RBCs from 3- to 4- and 6- to 8-week-old sph/sph mice was significantly higher than RBCs from adult mice (> 12 weeks old; P <.005). While the mechanism of infarction in these mice is unknown, we speculate that changes in RBC adhesive characteristics contribute to this pathology.

Soluble L-selectin, a marker of immune activation, in neonatal infection

L-Selectin is an adhesion molecule shed from the surface of lymphocytes and granulocytes upon activation. Soluble L-selectin in the plasma can thus reflect immune activation and is elevated in several pathological states. Our objective was to evaluate plasma levels of L-selectin as an immune activation marker in neonates and to determine whether it can serve as a marker of infection, either neonatal or congenital, or if it is affected by the mode of delivery and obstetrical or perinatal complications. A solid-phase ELISA was used on 89 sera from neonates less than 2 days of age, according to the manufacturer's instructions. Levels of soluble L-selectin in the neonate were lower than those of older infants and children and comparable to the levels seen in adults. There was no difference between levels of soluble L-selectin of premature (median, 1172 ng/ml) and full-term babies (median, 1151 ng/ml) or between babies born via vaginal (median, 1233 ng/ml) or cesarean delivery (median, 1146 ng/ml). Conditions such as preeclampsia or administration of steroids to the mother did not affect the levels of L-selectin in the neonate. In contrast, the presence of maternal clinical chorioamnionitis resulted in an increase in levels of L-selectin in the neonate (median, 1377 vs 1072 ng/ml, p = 0.02), as did neonatal sepsis (median, 1331 vs 1149 ng/ml, p = 0.026). Soluble L-selectin, and thus immune activation level, is highest in neonates with neonatal infection and needs to be further evaluated as a surrogate marker for diagnosing sepsis in the neonate.

Soluble E-selectin, soluble L-selectin and soluble ICAM-1 in bronchopulmonary dysplasia, and changes with dexamethasone

OBJECTIVE

To evaluate longitudinal change in arterial blood plasma levels of soluble adhesion molecules in infants of <30 weeks' gestation with respiratory distress syndrome (RDS) and to look for differences in these levels in neonates who subsequently developed bronchopulmonary dysplasia (BPD) compared with those neonates who did not, and also to investigate the effect of dexamethasone treatment on levels of soluble adhesion molecules in plasma.

METHODS

We measured plasma concentrations of soluble L-selectin (sL-selectin), soluble E-selectin (sE-selectin), and soluble intercellular adhesion molecule-1 on days 1, 3, 7, 14, 21, and 28 of life and before and 2 to 3 days after initiating a 6-day course of dexamethasone treatment. Infants with RDS were followed until discharge and were classified as non-BPD and either 1) BPD day 28 reflecting oxygen requirement on day 28 but not at 36 corrected weeks or 2) BPD 36 weeks reflecting oxygen requirement at 36 (corrected) weeks' gestation. The classification of presence or absence of BPD by oxygen requirement was supported by and was consistent with radiologic findings of BPD for all infants. The difference between BPD day 28 and BPD 36 weeks was supported by more extensive radiologic effects in the latter.

RESULTS

The arterial plasma level of sL-selectin in infants who had RDS and did not develop BPD was significantly decreased compared with term healthy infants, as was the level of sE-selectin. Compared with infants who had RDS and did not develop BPD, sL-selectin levels were even further decreased in infants who had RDS and did develop BPD both at birth and throughout the first 4 weeks of life (day 1 through day 28). Infants with BPD also showed increasing levels of sE-selectin during this period of time, whereas infants without BPD did not. Levels of soluble intercellular adhesion molecule-1 in infants without BPD were not different from infants with BPD initially but increased in infants with BPD compared with infants without BPD, significant on day 28 in both groups. Dexamethasone treatment increased concentration of sL-selectin and decreased concentration of sE-selectin.

CONCLUSIONS

Low sL-selectin may be an early indicator of enhanced risk for BPD. Low levels of sL-selectin and increasing levels of sE-selectin may be risk factors for BPD. The effects of dexamethasone treatment include significant modulation of adhesion molecules.

sCD31/sPECAM-1 levels in breast milk and sera of mother-infant pairs in the early postpartum period

Immunomediators seem to have a central role in the immune system of both human milk and newborn infants. CD31/PECAM-1 is an adhesion molecule, member of Ig gene superfamily, mediating cell-cell adhesion in both homophilic and heterophilic ways. Levels of the soluble form of PECAM-1 (sPECAM-1) were evaluated on the 2nd and 5th day postpartum in breast milk and serum paired samples from 20 lactating women as well as in time-matched serum from their single, term, healthy neonates. Concentrations of sPECAM-1 in breast milk (median, range) on both the 2nd (2.05 ng/ml, 0.0-7.2) and 5th day postpartum (0.89 ng/ml, 0.0-3.6) were about 10 and 20 times lower than those (mean +/- SD) in controls (healthy adults) (19.83 +/- 5.17, p<7 x 10(-8)), showing a significant fall from the 2nd to the 5th day postpartum (p<0.0005). Maternal serum sPECAM-1 values (mean +/- SD) were significantly lower on the 2nd day postpartum (14.21 +/- 5.15 ng/ml) than those in controls (p<0.002), but reached control values on the 5th day postpartum after a significant rise (p<0.0075). Neonatal serum sPECAM-1 values with no significant difference between the 2nd (14.4 +/- 4.11 ng/ml) and 5th day of life (14.54 +/- 4.99 ng/ml) were significantly lower than those in controls (p<0.002). Values of sPECAM-1 in milk and sera of lactating mothers and their neonates on the 2nd day postpartum depended on the mode of delivery, being significantly lower after caesarean section (p<0.034, p<0.0075 and p<0.035, respectively). In conclusion, our findings in the early postpartum period demonstrate that: (a) sPECAM-1 is present in human milk in low and decreasing concentrations; (b) the shedding of sPECAM-1 is an established component of the neonatal immune system from birth, though in lower concentrations than in adults, possibly reflecting its immaturity; and (c) the mode of delivery has a significant effect on sPECAM-1 values in milk and sera of lactating mothers and their neonates; the lower values after caesarean section may reveal a deranged endothelial homeostasis.