The cell adhesion molecule, VCAM-1, is selectively elevated in serum in pre-eclampsia: does this indicate the mechanism of leucocyte activation?

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.

Endothelial activation and cell adhesion molecule concentrations in pregnant women living at high altitude

OBJECTIVES

Maternal physiology at high altitude could be considered to resemble an intermediate state between preeclampsia and normal pregnancy. The objective of the current study was to determine if cell adhesion molecules, known to be increased in preeclampsia, are increased with chronic maternal and placental hypoxia (due to high-altitude residence) in the absence of preeclampsia.

METHODS

Serum was collected from women residing at 3100 m or 1600 m in the three trimesters of pregnancy and postpartum. Vascular cell adhesion molecule-1 (VCAM-1), E-selectin, and intercellular adhesion molecule-1 (ICAM-1) were measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

General linear model (GLM) repeated measures analysis of VCAM-1, E-selectin, and ICAM-1 data showed there were no statistically significant effects of gestation within either the high- or moderate-altitude groups or between the different altitudes.

CONCLUSION

The increase in cell adhesion molecules reported in preeclampsia is not present in pregnant women at high altitude, suggesting that maternal systemic hypoxia is not responsible for this pathway of endothelial cell activation in preeclampsia.

Plasma malondialdehyde, superoxide dismutase, sE-selectin, fibronectin, endothelin-1 and nitric oxide levels in women with preeclampsia

OBJECTIVE

The purpose of this study was to determine plasma malondialdehyde (MDA), superoxide dismutase (SOD), soluble E-selectin (sE-selectin), fibronectin, endothelin-1 (ET-1) and nitric oxide (NO) levels in women with preeclampsia and to find out the relations of diastolic blood pressure with these variables.

STUDY DESIGN

We performed a case-control study consisting of randomly selected 34 healthy pregnant women and 35 patients diagnosed as preeclampsia. Lipoperoxidation was ascertained by the formation of MDA. SOD activity was determined by the method of Sun et al. Plasma concentration of NO was estimated using colorimetric assay. Plasma ET-1 and sE-selectin were measured by enzyme-linked immunosorbent assay (ELISA). A nephelometric method for fibronectin quantitation was used.

RESULTS

The mean plasma level of MDA was significantly higher and SOD was significantly lower in preeclamptic pregnancies (P<0.001). Plasma concentrations of fibronectin, sE-selectin and ET-1 were significantly increased, whereas NO was significantly decreased in women with preeclampsia than normotensive women (P<0.001).

CONCLUSION

Increased plasma levels of MDA, fibronectin, sE-selectin, ET-1, and decreased plasma levels of NO and SOD in preeclamptic patients suggest that poorly perfused fetoplacental unit is the origin of oxygen free radicals and lipid peroxides.

The receptor for advanced glycation end products (RAGE) is elevated in women with preeclampsia

A leading theory of the pathophysiology of preeclampsia is that oxidative stress induces vascular endothelial cell dysfunction. Advanced glycation end products (AGEs) form when aldose sugars react nonenzymatically with proteins under conditions of oxidative stress. AGEs are circulating molecules and can generate reactive oxygen species and vascular dysfunction (in diabetes and atherosclerosis) through an association with cell surface receptors (RAGE). RAGE is a multiligand receptor, expressed in vascular tissue, which is upregulated by its own ligands. Insulin resistance and obesity are risk factors for developing preeclampsia, as well as being conditions that would increase RAGE levels. Thus, we hypothesized that women with preeclampsia will have elevated levels of RAGE protein compared with normal pregnant women. Biopsies of nonlaboring myometrium as well as omentum were taken from normal pregnant and preeclamptic women. Nonpregnant samples were obtained at the time of hysterectomy. Tissue sections were immunostained with anti-RAGE as well as anti-alpha-actin and anti-von Willebrand factor (to identify blood vessels and intact endothelial cells). Staining intensity was qualitatively described as well as given an intensity score, with the identity of the section concealed. Nonpregnant myometrial and omental vessels showed very low to undetectable levels of RAGE staining. Pregnancy induced a significant increase in RAGE protein levels in both myometrium and omental vasculature. Blood vessels from women with preeclampsia consistently had intense staining for RAGE in both vessel beds. Thus, our data suggest that since RAGE activation can induce similar pathophysiologic changes to those observed in women with preeclampsia (including NFkappaB activation, increased TNFalpha and endothelin), elevated RAGE protein may be contributing to the vascular dysfunction in preeclampsia.

Women with preeclampsia have increased serum levels of pregnancy-associated plasma protein A (PAPP-A), inhibin A, activin A and soluble E-selectin

OBJECTIVE

Poor placentation in early pregnancy is thought to lead to an excessive maternal systemic inflammatory response, which causes the maternal syndrome of preeclampsia. The aims of this retrospective study were to confirm old reports of increased blood levels of pregnancy-associated plasma protein A (PAPP-A) in preeclampsia and how its levels correlate with the levels of other placental and endothelial proteins that are reported to be elevated in preeclampsia.

METHODS

Nineteen women with preeclampsia symptoms were matched with 19 normal pregnant controls for gestational age, maternal age, and parity. PAPP-A, placental pregnancy-specific beta1-glycoprotein (SP1), inhibin A, activin A, and sE-selectin were measured in serum using specific ELISAs.

RESULTS

Maternal serum levels of PAPP-A, inhibin A, activin A and sE-selectin were increased in women with preeclampsia (mean 157.7 vs. 76.85 mIU/mL, p=0.005; 3.08 vs. 1.51 ng/mL, p=0.002, 32.36 vs. 3.77 ng/mL, p<0.001 and 62.15 vs. 46.37 ng/mL, p=0.02 respectively), compared to controls. Serum levels of SP1 were not altered in preeclampsia. PAPP-A (r=0.636, p<0.01) had a positive correlation with sE-selectin in patients with preeclampsia. Serum inhibin A and activin A had a significant positive correlation with each other in preeclampsia.

CONCLUSIONS

Raised levels of PAPP-A in preeclampsia confirm earlier reports. Activin A showed the highest increase over the controls and is thus likely to be a better serum marker for this pathology than the other markers that were tested.

Elevated soluble adhesion molecules in women with pre-eclampsia. Do cytokines like tumour necrosis factor-alpha and interleukin-1beta cause endothelial activation

OBJECTIVE

The purpose of the present study was to evaluate the clinical significance of tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) for endothelial cell activation in pre-eclampsia. Therefore, we determined and compared the correlations between these cytokines and circulating adhesion molecules in the sera of pre-eclamptic pregnant women, normotensive pregnant women and nonpregnant women.

METHODS

The soluble adhesion molecules VCAM-1, ICAM-1, E-selectin, and P-selectin were determined in the serum of 38 pre-eclamptic pregnant women and 40 normotensive pregnant and nonpregnant controls using ELISA-techniques. We correlated these serum concentrations with the serum levels of TNF-alpha and IL-1beta, respectively, also determined by ELISA.

RESULTS

Elevated serum levels of VCAM-1 and E-selectin could be detected in pre-eclamptic patients, with and without HELLP-syndrome. In contrast, no increased serum concentration of ICAM-1, P-selectin, TNF-alpha and IL-1beta were found in these patients. While significant correlation between VCAM-1 and E-selectin could be determined (r=0.604; p<0.001) no unambiguous correlations, however, were found between TNF-alpha or between IL-1beta and the examined adhesion molecules or the selectins.

CONCLUSIONS

In contrast to in vitro investigations on cultured umbilical vein endothelium, our experimental results indicate that the cytokines TNF-alpha and IL-1beta can not explain endothelial cell activation, and that their measurement in serum is not useful for the detection of pre-eclampsia.

A selective increase in plasma soluble vascular cell adhesion molecule-1 levels in preeclampsia

PROBLEM

The study was conducted to determine whether altered plasma levels of soluble intercellular adhesion molecule (ICAM)-1 and soluble vascular cell adhesion molecule (VCAM)-1 are involved in the pathogenesis of preeclampsia.

METHOD OF STUDY

Maternal plasma samples were collected from 20 patients with preeclampsia, 20 matched normotensive patients with uncomplicated pregnancies. and ten healthy nonpregnant women. Samples were assayed for soluble VCAM-1 and soluble ICAM-1 by specific enzyme-linked immunosorbent assay.

RESULTS

Both soluble VCAM-1 and soluble ICAM-1 were detectable in the plasma of all preeclamptic, normotensive pregnant, and nonpregnant women. The mean plasma level of soluble VCAM-1 was significantly higher in preeclamptic women compared to normotensive pregnant women (1831 ng/mL +/- 534 ng/mL vs. 1254 ng/mL +/- 386 ng/mL, respectively; P < 0.05). However, the plasma level of soluble VCAM-1 was unchanged during the third-trimester of normal pregnancy compared to nonpregnant women. The mean plasma level of soluble ICAM-1 in preeclamptic and normotensive pregnant women were increased when compared to nonpregnant women. However, the mean plasma level of soluble ICAM-1 was comparable in women with preeclampsia and normotensive pregnancy.

CONCLUSIONS

The selective increased plasma levels of soluble VCAM-1 in patients with preeclampsia provide evidence for endothelial activation and suggest distinct pathways for neutrophil and endothelial activation in preeclampsia.

The role of soluble adhesion molecules in evaluating endothelial cell activation in preeclampsia

OBJECTIVE

Adhesion molecules, such as vascular cell adhesion molecule 1, are known to be increased in the serum of patients with preeclampsia, indicating that these molecules are possible markers of endothelial cell activation. We investigated the influence of serum from women with preeclampsia on the expression of adhesion molecules by cultured endothelial cells.

STUDY DESIGN

Human umbilical vein endothelial cells were cultured in Ham/Iscove modified Dulbecco's medium containing 20% pooled human serum, l -glutamine (200 mmol/L), penicillin, and streptomycin. We stimulated these cells for 24 hours with sera from patients with preeclampsia and then determined the levels of vascular cell adhesion molecule 1, intercellular cell adhesion molecule 1, E-selectin, and P-selectin in the supernatant and in the maternal serum by means of enzyme-linked immunosorbent assay. These results were compared with those of sera obtained from normotensive pregnant and nonpregnant women. In addition, the expressions of these adhesion molecules on the endothelial surface were determined by immunofluo-rescence microscopy.

RESULTS

Only for vascular cell adhesion molecule 1 and E-selectin were elevated plasma levels found in hypertensive patients, whereas intercellular cell adhesion molecule 1 and P-selectin showed similar plasma levels in all the patients. No differences in the levels of the adhesion molecules were found between the supernatants of endothelial cell cultures after stimulation with sera from patients with preeclampsia and those after stimulation with normotensive control sera. In contrast, with immunofluorescence microscopy we could detect higher amounts of vascular cell adhesion molecule 1, intercellular cell adhesion molecule 1, and E-selectin on the endothelial surface after stimulation with sera from women with preeclampsia.

CONCLUSION

Although vascular cell adhesion molecule 1 and E-selectin were elevated in maternal serum samples from women with preeclampsia and on the endothelial surface after stimulation with such sera, there were no detectable increases in the levels of both of these adhesion molecules in the supernatant of cultured endothelial cells. We therefore assume that sera from women with preeclampsia may cause endothelial cell activation. Because we could not detect elevated concentrations of any of the investigated adhesion molecules in the supernatant of endothelial cells, we believe that factors other than sera from women with preeclampsia seem to play a major role in the release of soluble forms of adhesion molecules from the endothelial membrane.

Plasma concentrations of asymmetric dimethylarginine, a natural inhibitor of nitric oxide synthase, in normal pregnancy and preeclampsia

OBJECTIVE

We investigated the change in the plasma concentration of asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide synthase, in early-, mid-, and late-gestation normotensive pregnancies and in gestational age-matched preeclamptic pregnancies and compared the observed changes with changes in blood pressure.

STUDY DESIGN

Blood pressure and peripheral plasma asymmetric dimethylarginine concentrations were measured in 20 nonpregnant and 145 pregnant women (33 first-trimester, 50 second-trimester, and 44 third-trimester normotensive pregnancies and 18 third-trimester pregnancies complicated by preeclampsia). In 23 normotensive pregnancies serial plasma asymmetric dimethylarginine concentrations were measured. Statistical analysis was by analysis of variance and linear regression.

RESULTS

The blood pressures recorded throughout normal pregnancy were significantly lower than in nonpregnant subjects (p < 0.0001). The mean systolic, diastolic, and average blood pressures were significantly higher in the second-trimester groups than in the first-trimester groups, whereas in the third trimester average and diastolic blood pressures were significantly higher than in the second trimester. The mean (+/-SD) systolic and diastolic blood pressures in third-trimester preeclamptic patients was 157.7 +/- 11.2 and 110.9 +/- 8.5 mm Hg. The mean plasma asymmetric dimethylarginine concentration in nonpregnant women was 0.82 +/- 0.31 micromol/L (significantly higher than in normotensive pregnancy, p < 0.0001). The plasma asymmetric dimethylarginine concentration was also significantly higher in second-trimester than in first-trimester normotensive groups (respectively, 0.52 +/- 0.20 micromol/L and 0.40 +/- 0.15 micromol/L, p = 0.001) and was higher in third-trimester normotensive pregnancy 0.56 +/- 0.23 micromol/L than it was in the second trimester. The asymmetric dimethylarginine concentration in third-trimester preeclamptic patients was 1.17 +/- 0.42 micromol/L (p < 0.0001 vs normotensive third-trimester subjects).

CONCLUSIONS

It is well recognized that blood pressure falls in early normal pregnancy and rises again toward term. These studies show that the early fall in blood pressure is accompanied by a significant fall in the plasma asymmetric dimethylarginine concentration. Later in pregnancy circulating concentrations increase and, when pregnancy is complicated by preeclampsia, concentrations are higher than in the nonpregnant state. Our data support a role for both asymmetric dimethylarginine and nitric oxide in the changes in blood pressure seen in both normal and preeclamptic pregnancy.

Increased levels of intercellular adhesion molecules and vascular cell adhesion molecules in pre-eclampsia

OBJECTIVE

To investigate the correlation between soluble forms of the intercellular adhesion molecule (sICAM-1) and vascular cell adhesion molecule (sVCAM-1) and the severity of pre-eclampsia or its possible consequences for fetal growth.

DESIGN

Prospective observational study.

SETTING

Institute of Medical Genetics, University of Oslo, Department of Medical Genetics and Haematological Research Laboratory, Ullevål University Hospital; and the Department of Obstetrics and Gynaecology, The National Hospital, Oslo, Norway.

PARTICIPANTS

Seventy-six women with normotensive pregnancies and 157 women with pre-eclampsia divided into three subgroups: mild, severe and pre-eclampsia with fetal growth retardation.

METHODS

ELISA-measurements of plasma sICAM-1 and sVCAM-1 were performed in a group of healthy pregnant normotensive women and three groups of women with varying degrees of pre-eclampsia.

RESULTS

sICAM-1 concentrations were higher in the pre-eclampsia group compared with the control group, but this difference was not statistically significant. Plasma concentrations of sVCAM-1 were significantly greater (P < 0.0001) in all pre-eclampsia subgroups (835.34, 855.25 and 964.05 ng/mL) compared with the control group (667.62 ng/mL). Within the pre-eclampsia group, plasma concentration of sVCAM-1 was significantly higher in the subgroup exhibiting fetal growth retardation (P = 0.03) compared with mild pre-eclampsia.

CONCLUSION

The observed increases in plasma concentrations of sVCAM-1 suggest that measurements of this adhesion molecule may be useful in monitoring pregnancies with respect to the development of pre-eclampsia or fetal growth retardation.

Placental cytokines and the pathogenesis of preeclampsia

The authors explore the hypothesis that tumor necrosis factor-alpha (TNF-alpha) and possibly other inflammatory cytokines are overproduced by the placenta in response to local ischemia/hypoxia contributing to increased plasma levels, and subsequent endothelial activation and dysfunction in the pregnancy disorder, preeclampsia. It is widely held that inadequate trophoblast invasion and physiologic remodeling of spiral arteries initiate placental ischemia/hypoxia in preeclampsia. Furthermore, focal areas of placental hypoxia have been implicated in the production of "toxic" factor(s) by the placenta, which circulate and cause maternal disease. Placental trophoblast cells and fetoplacental macrophages normally produce TNF-alpha and interleukin-1 (IL-1), which are capable of producing endothelial cell activation and dysfunction. Hypoxia has recently been reported to increase TNF-alpha and IL-1 production by term villous explants from the human placenta. Placental cells also express erythropoietin (EPO), which is the prototype molecule for transcriptional regulation by hypoxia in mammals. Interestingly, TNF-alpha and IL-1 have DNA sequence homologous or nearly homologous to the hypoxia-responsive enhancer element of the EPO gene, thus providing a potential, but as of yet, untested molecular link between placental hypoxia and stimulation of cytokine production. Inflammatory cytokines overproduced by the placenta in response to hypoxia may then lead to increased plasma levels and endothelial activation and dysfunction in preeclampsia. The purpose of this short review is to critically evaluate the hypothesis that placental cytokines contribute to the pathogenesis of preeclampsia. Of note, the etiology of the disease presumably related to deficient trophoblast invasion is beyond the scope of this work.

Increased maternal plasma levels of soluble adhesion molecules (ICAM-1, VCAM-1, E-selectin) in preeclampsia

The physiological significance of soluble adhesion molecules has not been elucidated but it has been reported that a number of cytokines may increase the cleavage of soluble adhesion molecules. The fact that preeclampsia is associated with both increased cytokine concentrations and endothelial cell damage led us to analyse levels of soluble adhesion molecules in preeclamptic women and to compare these levels to the disease state. Since the cytokine network is altered by reproduction, the present study also raised the question as to whether levels of soluble adhesion molecules differ between pregnant and non-pregnant women, and whether variations occur with relation to gestational age or delivery. Levels of soluble adhesion molecules (intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin) in 25 preeclamptic women were compared to those in healthy pregnant women matched for age, parity and gestation, and the levels of soluble adhesion molecules of 40 healthy pregnant women at different gestational ages were determined and compared to those of 15 non-pregnant women. Concentrations were measured by ELISAs. Levels of ICAM-1, VCAM-1 and E-selectin concentrations were elevated in preeclamptic pregnancies, whereas serum levels in normal pregnancy did not differ from those of non-pregnant women. No changes were observed in relation to gestational age or delivery.