Soluble tumor necrosis factor receptors and soluble interleukin-6 receptor in fetal and maternal sera, coelomic and amniotic fluids in normal and pre-eclamptic pregnancies

Characterization of Natural Killer Cells and Cytokines in Maternal Placenta and Fetus of Diabetic Mothers

The present study characterized natural killer cells and cytokines in diabetic mothers, their placenta, and fetus. In the maternal blood from the hyperglycemic groups, the CD16⁺CD56⁻ NK cells increased, whereas that of CD16⁺CD56⁺ decreased in gestational diabetes mellitus [GDM] group. Cord blood from type 2 diabetes [DM-2] showed a higher proportion of CD16⁺CD56⁻ and CD16⁻CD56⁺. The placental extravillous layer of GDM and DM-2 showed an increase of CD16⁺CD56⁻ cells and, irrespective of region, the proportion of CD16⁻CD56⁺ cells was higher in mild gestational hyperglycemia [MGH] and GDM and lower in DM-2. IL-2 was lower in maternal blood and IFN-γ higher in maternal and cord blood from the GDM group. IL-17 was higher in maternal and cord blood from the DM-2 group. The placental extravillous layer of the MGH showed high levels of IL-4, IL-6, IL-10, IL-17, and IFN-γ and low levels of IL-1β and IL-8, whereas the placental villous layer contained high levels of IL-17 and IFN-γ. The GDM group, irrespective of region, showed higher levels of IL-8. The DM-2 group, irrespective of region, placenta showed high levels of TNF-α, IL-17, and IFN-γ. The hyperglycemia produces an inflammatory environment with a high content of inflammatory cytokines and cells expressing CD16⁺.

Differential regulation of TNF receptors in maternal leukocytes is associated with severe preterm preeclampsia

We tested the hypothesis that maternal peripheral blood leukocytes contribute to elevated levels of soluble TNF receptors (sTNFR) in preeclampsia (PE) with concomitant intrauterine growth restriction (IUGR). TNFR1 and TNFR2 were evaluated in a cross-sectional study comparing preeclamptic (n = 15) with or without IUGR versus normotensive pregnant women (PREG, n = 30), and non-pregnant controls (Con; n = 20). Plasma levels of sTNFR1 were higher in PE (1675.0 ± 227.1 pg/mL) compared with PREG (1035.0 ± 101.1 pg/mL) and Con (589.3 ± 82.67 pg/mL), with the highest values observed in PE with IUGR (2624.0 ± 421.4 pg/mL; n = 6). Plasma sTNFR2 was higher during pregnancy (PE: 1836.0 ± 198.7 pg/mL; PREG: 1697.0 ± 95.0 pg/mL) compared with Con (598.3 ± 82.7 pg/mL). Urinary levels of sTNFR1 and sTNFR2 were higher in PE and PREG compared with the Con group. Abundance of TNFR1 mRNA in peripheral blood leukocytes was strongly correlated with plasma levels of sTNFR1 in PE. However, TNFR2 mRNA accumulation in leukocytes did not correlate with sTNFR2 plasma levels. The level of sTNFR1 in plasma was correlated with body weight of the newborn (r = -0.56). The data suggest that maternal leukocytes contribute to sTNFR1 levels in plasma in association with decreasing newborn weight and PE with concomitant IUGR.

Soluble endoglin, transforming growth factor-Beta 1 and soluble tumor necrosis factor alpha receptors in different clinical manifestations of preeclampsia

Background

Despite intensive research, the etiopathogenesis of preeclampsia (PE) remains uncertain. Inflammatory and angiogenic factors are thought to play considerable roles in this disease. The objective of this study was to investigate the association between soluble endoglin (sEng), transforming growth factor beta-1 (TGF-β1) and tumor necrosis factor alpha soluble receptors (sTNF-Rs) and the clinical manifestations of PE.

Methods

Plasma levels of sEng, TGF-β1 and sTNF-Rs were determined by ELISA in 23 non-pregnant, 21 normotensive pregnant and 43 PE women. PE women were stratified into subgroups according to the severity [mild (n = 12) and severe (n = 31)] and onset-time of the disease [early (n = 19) and late (n = 24)].

Results

Pregnancy was associated with higher levels of sEng, sTNF-R1 and sTNF-R2 than the non-pregnant state. Moreover, PE women had higher levels of sEng and sTNF-R1 than normotensive pregnant women. No difference was found in TGF-β1 levels, comparing the three study groups. Late PE had higher levels of sTNF-R1 and sTNF-R2 than early PE. No significant differences were found in sEng and TGF-β1 comparing early and late PE. sEng levels were higher in severe PE than in mild PE and no difference was found for TGF-β1, sTNF-R1 and sTNF-R2 levels. There was a positive correlation among sEng, TNF-R1 and sTNF-2 levels. Logistic regression analysis revealed that primiparity and sEng levels are independently associated with the development of PE. Furthermore, sEng levels are independently associated with the disease severity.

Conclusions

These results suggest that pregnancy is a condition associated with higher levels of anti-angiogenic and pro-inflammatory factors than the non-pregnant state and that PE is associated with an imbalance of these factors in the maternal circulation.

Plasma IL-17, IL-35, interferon-γ, SOCS3 and TGF-β levels in pregnant women with preeclampsia, and their relation with severity of disease

Abstract Objective: To research the hypothesis of preeclampsia (PE) is associated with increased systemic inflammatory responses of Th1-type as well as decreased Th2-type responses; we evaluated the maternal plasma levels of IFN-gamma, TNF-alpha, TGF-beta, IL-4, IL-6, IL-10, IL-17, IL-35 and SOCS3 in preeclamptic and healthy pregnants.

METHODS

This study was conducted with 40 preeclamptic (study group) and 40 normotensive pregnant (control) women in third trimester when they were admitted to the labor and delivery unit. The extracted maternal plasma samples were assayed by an enzyme-linked immunosorbent assay. Statistical analysis was performed by SPSS 16.0 version.

RESULTS

While IFN-gamma and TGF-beta levels of preeclamptic women were significantly higher (p < 0.01), IL-35 and IL-17 levels of preeclamptic women were significantly lower (p < 0.01) than those of controls. The ratios of IFN-gamma/IL-10, IFN-gamma/IL-6, IFN-gamma/IL-4 were significantly high and ratio of IL-35/IL-17 was significantly low in the PE group compared to those in the control group. Maternal plasma SOCS3 levels showed negative correlation with blood pressure and proteinuria severity, but none of the cytokines showed influence on blood pressure and proteinuria after adjusting for maternal and gestational age.

CONCLUSIONS

Increased IFN-gamma/TGF-beta production and reduced IL-35/IL-17/SOCS3 production in preeclamptic women may lead to less cytokine inhibitory activity in PE, which may account for the increased proteinuria and blood pressure in PE.

Adiposity-related inflammation: effects of pregnancy

In the nonpregnant population, there is extensive evidence of a systemic low-grade inflammatory status in relation to excess adipose tissue. Less is known about the relation during pregnancy.

OBJECTIVE

Our main objective was therefore to explore the effect of pregnancy on adiposity-related systemic inflammation.

DESIGN AND METHODS

This study is a longitudinal cohort study of 240 pregnant women of Scandinavian heritage at Oslo University hospital-Rikshospitalet, Norway from 2002 to 2005. The inflammatory markers (C-reactive protein [CRP], Interleukin-6 [IL-6], monocyte chemoattractant protein 1 [MCP-1], IL1-Ra, tumor necrosis factor receptor II, and IL-10) were measured at four timepoints during pregnancy and analyzed by enzyme immuno-assay. The women were categorized based on BMI at inclusion (BMI <25, 25-30, and >30 kg/m(2)). Data were analyzed by Friedman-test, Wilcoxon signed rank test, or Kruskal-Wallis test as appropriate.

RESULTS

Maternal adiposity was associated with significantly higher circulatory levels of several inflammatory markers (CRP, MCP-1, IL-6, and IL-1Ra). However, this proinflammatory upregulation was not evident toward the end of pregnancy, as levels of CRP, MCP-1, and IL-6 were not any longer significantly different between the BMI categories.

CONCLUSIONS

Although normal pregnancy exhibits proinflammatory features, this does not seem to have additive or synergistic effects on the inflammation associated with adiposity. On the contrary, we found that the BMI-dependent increase in proinflammatory markers was not evident at the end of pregnancy.

Elevated maternal soluble Gp130 and IL-6 levels and reduced Gp130 and SOCS-3 expressions in women complicated with preeclampsia

Increased inflammatory response plays a significant role in the vascular pathophysiology in preeclampsia. However, the mechanism for increased inflammatory response in preeclampsia is largely unknown. Interleukin (IL)-6 levels are elevated in women with preeclampsia. IL-6 and its receptors, IL-6R and glycoprotein (gp)130, play a critical role in mediating antiinflammatory response via induction of SOCS-3 (suppressor of cytokine signaling-3). However, IL-6 receptor levels and expressions have not been studied in preeclampsia. In this study, we measured IL-6 and its 2 soluble receptors, soluble IL-6R and soluble gp130, in maternal plasma from normal and preeclamptic pregnant women and found that not only IL-6 but also soluble gp130 levels were significantly higher in preeclamptic women than in normotensive pregnant controls. We further examined IL-6R, gp130, and SOCS-3 expressions in maternal vessels and leukocytes and found that gp130 and SOCS-3 expressions were downregulated in both vessel endothelium and leukocytes from preeclampsia. Different patterns for IL-6R and gp130 expressions were found. IL-6R expression was also downregulated in leukocytes from preeclampsia. Our results suggest that increased plasma soluble gp130/soluble IL-6R/IL-6 ratio and reduced membrane transsignaling gp130 expression could contribute to decreased SOCS-3 expression and subsequent reduction in SOCS-3 antiinflammatory activity in women with preeclampsia. Thus, reduced gp130 and SOCS-3 expressions may offer, at least in part, a plausible explanation of reduced antiinflammatory protection in the maternal vascular system in preeclampsia.

Maternal plasma concentrations of the soluble tumor necrosis factor receptor 2 are increased prior to the diagnosis of preeclampsia

OBJECTIVE

Soluble receptor levels of tumor necrosis factor (sTNF-R)-1 and -2 are increased during preeclampsia. We postulated the increase preceded overt disease.

STUDY DESIGN

Archived plasma from the Eunice Kennedy Shriver National Institute of Child Health and Human Development aspirin to prevent preeclampsia in high risk women trial were used to measure serial sTNF-R1 and sTNF-R2 (enrollment, 24-28 week's gestation) in 986 women (577 also sampled at 34-38 weeks).

RESULTS

Preeclampsia incidence was 21.2%. sTNF-R2 levels were higher at enrollment (P = .02) and weeks 24-28 (P = .01) in women who eventually developed preeclampsia. The magnitude of increase from baseline of both receptors was significantly greater in women who developed preeclampsia in the future. Women with week 24-28 sTNF-R2 levels in the highest quartile had significantly increased odds to develop preeclampsia (P = .03 vs quartile 1). This association was observed in the placebo but not the aspirin arm (P

CONCLUSION

sTNF-R2 levels are elevated prior to overt preeclampsia, suggesting a pathogenetic role for these proinflammatory cytokines.

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Key Words Collapse

MESH Headings

• Adult
• Female
• Humans
• Pre-Eclampsia/blood
• Pre-Eclampsia/diagnosis
• Predictive Value of Tests
• Pregnancy
• Receptors, Tumor Necrosis Factor, Type II/blood
• Time Factors

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Grants

• HD36801 NICHD NIH HHS
• UG1 HD027869 NICHD NIH HHS
• HD27869 NICHD NIH HHS
• U10 HD040485 NICHD NIH HHS
• U10 HD027883 NICHD NIH HHS
• U10 HD027917 NICHD NIH HHS
• U10 HD027915 NICHD NIH HHS
• U10 HD027860 NICHD NIH HHS
• Intramural NIH HHS
• HD27889 NICHD NIH HHS
• U01 HD019897 NICHD NIH HHS
• HD27915 NICHD NIH HHS
• U01 HD036801 NICHD NIH HHS
• HD27861 NICHD NIH HHS
• U10 HD021414-14S1 NICHD NIH HHS
• HD27860 NICHD NIH HHS
• UG1 HD027915 NICHD NIH HHS
• HD21414 NICHD NIH HHS
• U10 HD027905 NICHD NIH HHS
• HD21410 NICHD NIH HHS
• U10 HD027869 NICHD NIH HHS
• HD27917 NICHD NIH HHS
• U10 HD021410 NICHD NIH HHS
• U10 HD036801 NICHD NIH HHS
• HD21434 NICHD NIH HHS
• U24 HD036801 NICHD NIH HHS

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Affiliation(s)

Baha Sibai Department of Obstetrics and Gynecology, University of Tennessee, Memphis, TN, USA
Roberto Romero
Mark A Klebanoff
Madeline Murguia Rice
Steve Caritis
Marshall D Lindheimer
J Peter Van Dorsten
Mark Landon
Menachem Miodovnik
Mitchell Dombrowski
Paul Meis

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Maternal and cord plasma cytokine and chemokine profile in pregnancies complicated by asthma

The mechanisms contributing to worsening of asthma during pregnancy have not been well characterized. Both asthma and pregnancy are conditions associated with a skewing of the immune response from T helper (Th) 1 toward a Th2 response. We hypothesise that worsening of asthma during pregnancy may be due to an enhanced production of circulating proinflammatory cytokines and chemokines and this may be modified by the use of inhaled glucocorticoid treatment. Peripheral blood was collected from asthmatic (n=35) and control non-asthmatic patients (n=13) in the third trimester (30-37 weeks) of pregnancy. Fetal blood was collected from the umbilical vein of the placenta after delivery from normal (n=24) and pregnancies complicated by asthma (n=24). Plasma samples were assayed for IL-6, -8, eotaxin and RANTES using conventional ELISA. In addition, a range of Th1 and Th2 cytokines measured using Luminex system. There were no significant differences in the levels of maternal IL-6, IL-8, eotaxin and RANTES between asthmatics and nonasthmatics. The results of this study suggest that the presence of asthma does not result in an enhanced circulation of Th2 related cytokines and chemokines during the third trimester of pregnancy. Furthermore peripheral blood cytokine concentrations appear unaffected by inhaled glucocorticoid treatment. Cord plasma eotaxin concentrations were increased in pregnancies complicated by asthma, compared with control. This is the first study to show increased eotaxin production in the feto-placental unit of asthmatic pregnancies and may be one mechanism by which allergy susceptibility is increased in the offspring of asthmatic women.

Simultaneous Measurement of 25 Inflammatory Markers and Neurotrophins in Neonatal Dried Blood Spots by Immunoassay with xMAP Technology

Background: Inflammatory reactions and other events in early life may be part of the etiology of late-onset diseases, including cerebral palsy, autism, and type 1 diabetes. Most neonatal screening programs for congenital disorders are based on analysis of dried blood spot samples (DBSS), and stored residual DBSS constitute a valuable resource for research into the etiology of these diseases. The small amount of blood available, however, limits the number of analytes that can be determined by traditional immunoassay methodologies.

Methods: We used new multiplexed sandwich immunoassays based on flowmetric Luminex® xMAP technology to measure inflammatory markers and neutrophins in DBSS.

Results: The high-capacity 25-plex multianalyte method measured 23 inflammatory and trophic cytokines, triggering receptor expressed on myeloid cells-1 (TREM-1), and C-reactive protein in two 3.2-mm punches from DBSS. It also measured 26 cytokines and TREM-1 in serum. Standards Recovery in the 25-plex method were 90%–161% (mean, 105%). The low end of the working range for all 25 analytes covered concentrations found in DBSS from healthy newborns. Mean recovery of exogenous analytes added at physiologic concentrations in DBSS models was 174%, mean intra- and interassay CVs were 6.2% and 16%, respectively, and the mean correlation between added and measured analytes was r2 = 0.91. In DBSS routinely collected on days 5–7 from 8 newborns with documented inflammatory reactions at birth, the method detected significantly changed concentrations of inflammatory cytokines. Measurements on DBSS stored at −24 °C for &gt;20 years showed that most cytokines are detectable in equal concentrations over time.

Conclusions: The method can reliably measure 25 inflammatory markers and growth factors in DBSS. It has a large potential for high-capacity analysis of DBSS in epidemiologic case–control studies and, with further refinements, in neonatal screening.

The influence of the mode of delivery on circulating cytokine concentrations in the perinatal period

BACKGROUND

Cytokines play an important role during labor and full- or preterm delivery. They influence physical immunity of the fetus-neonate and express a leading role in the perinatal period, being present in maternal and fetal tissues.

AIM

To investigate whether cytokine concentrations in the mother, fetus and neonate depend on the labor and the mode of the delivery.

STUDY DESIGN

Prospective study.

SUBJECTS

Seventy-eight healthy, non-smoking parturients (mean age 28+/-4, range 21-39 years, delivering vaginally: n=52 or by elective cesarean section: n=26) and their single, healthy, appropriate for gestational age, full-term neonates.

OUTCOME MEASURES

We correlated determined circulating levels of IL-2, sIL-2R, IL-4, sIL-4R, IL-6, sIL-6R, IL-1beta, IL-8, IFN-gamma, TNF-alpha, sTNF RI, sTNF RII and RANTES in the mothers before delivery (MS), the fetuses (UC) and the neonates in days 1 (N1) and 4 (N4) of life, with the mode of delivery.

RESULTS

sIL-2R in N1 and N4, sIL-4R in MS, IL-6 in MS and UC, IL-1beta in MS, UC and N1, IFN-gamma in MS and UC, TNF-alpha in UC, N1 and N4, sTNF RI in UC were significantly higher in cases of vaginal delivery than in cases of elective cesarean section (p ranging from 0.0005 to 0.05).

CONCLUSIONS

Vaginal delivery promotes the production of various cytokines and their receptors, which are implicated in neonatal immunity.

A review of the role of proinflammatory cytokines in labor and noninfectious preterm labor

The prevention of preterm labor has the potential to reduce newborn morbidity and mortality by decreasing the incidence of preterm birth. Half of all preterm births occur in women with no known clinical risk factors. Labor onset and progress is multifactorial, and we are just beginning to understand the role of cytokines in uterine activity. The purpose of this article is to review the role of cytokines in labor and preterm labor not associated with infection and to provide implications for research and practice.

Cytokine soluble receptors in perinatal and early neonatal life

BACKGROUND

In contrast to cellular receptors, soluble receptors do not enhance the cellular activation because they do not have transmembranic and cytoplasmic parts, acting thereby as endogenous regulatory mechanisms against systemic functions of cytokines.

AIM

To measure serum concentrations of the soluble interleukin-2 receptor (sIL2R), soluble interleukin-4 receptor (sIL4R), soluble interleukin-6 receptor (sIL6R), and soluble tumor necrosis factor-alpha receptor I and soluble tumor necrosis factor-alpha receptor II, during the perinatal and early neonatal period, in order to evaluate their role in activation of immune response in labor and the first days postpartum.

METHODS

Soluble receptor serum concentrations were determined by enzyme-linked immunosorbent assay, in 45 healthy, full-termed neonates during the first and fifth days after birth, in 25 of their mothers (MS), in 25 samples of umbilical cords (UC) and in 25 healthy adult donors age-matched with the mothers (controls).

RESULTS

Soluble receptor serum concentrations showed considerable changes during labor and early neonatal life, being significantly higher both in MS (except sIL6R) and in neonatal sample UC, first and fifth days after birth, compared with controls (p<0.0001). Neonatal serum sIL2R and sIL6R increased significantly from birth to the fifth day, while the remaining receptors showed a rapid increase in the first day (p<0.0001), declining significantly thereafter (p<0.0001).

CONCLUSION

Our findings suggest that the elevated concentrations of all studied soluble cytokine receptors reflect the activation of immune response, and represent also regulatory protective mechanisms for mother and fetus-neonate against the systemic function of cytokines during labor and early neonatal life.

Measurement of cytokines in clinical samples using immunoassays: problems and pitfalls

With the explosion in interest in cytokines and an increasing understanding of their possible involvement in the pathogenesis of many diseases, the number of studies measuring cytokines in body fluids has increased markedly over the last 5 to 10 years. However, it is readily apparent from the literature that the level of awareness of the many factors that can potentially influence the results obtained is very low. Such factors are likely to contribute considerably to the disparities seen among similar types of study. These include assay properties such as standardization and specificity, type of sample and sample handling, and many biological influences such as age, sex, ethnic background, and diurnal rhythmicity. Clearly, it is not possible to control for all these factors, but a minimum evaluation of assays should be carried out as described, including recovery and parallelity studies using relevant samples and the establishment of reproducibility and normal healthy population levels. An awareness of these factors, which is the purpose of this review, may hopefully lead to an improvement in the quality of studies incorporating the measurement of cytokines in clinical samples and should aid in the interpretation of the data.

The immunology of preeclampsia

The immune maladaptation hypothesis of preeclampsia is concordant with cytokine-mediated oxidative stress, chronology of endothelial activation, lipid changes, adverse effect of changing partners, and the protective effect of sperm exposure. Genetic factors may involve underlying hereditary thrombophilic disorders and hyperhomocysteinemia, essential hypertension and/or obesity, or control of the Th1/Th2 balance and thus affect the maternal response against fetal antigens. Placental ischemia and increased syncytiotrophoblast deportation are probably end-stage disease phenomena.

Cytokine and interferon research in Israel

From its inception, the field of interferons and cytokines has occupied an important position in Israeli biological science. With the Second Joint Meeting of the International Society for Interferon and Cytokine Research and the International Cytokine Society taking place in Jerusalem in 1998, it is timely to review here current Israeli research on the biology, gene regulation, receptors, signal transduction, mode of action and clinical aspects of interferons and cytokines.

Circulating bioactive tumor necrosis factor-alpha, tumor necrosis factor-alpha receptors, fibronectin, and tumor necrosis factor-alpha inducible cell adhesion molecule VCAM-1 in uncomplicated pregnancy

OBJECTIVES

Our goal was to assess in a longitudinal study of uncomplicated pregnancy the course of maternal plasma concentrations of the bioactive cytokine tumor necrosis factor-alpha, the soluble tumor necrosis factor-alpha receptors sTNFRI and sTNFRII, the soluble cell adhesion molecule sVCAM-1, and circulating fibronectin.

STUDY DESIGN

Blood was collected from 22 healthy pregnant women at 7 to 17, 18 to 22, 23 to 28, and 30 to 36 weeks' gestation and post partum. Plasma samples were measured by bioassay for bioactive tumor necrosis factor-alpha, by immunoassay for sTNFRI, sTNFRII, and VCAM-1, and by radial immunodiffusion for circulating fibronectin, and data were statistically analyzed.

RESULTS

Plasma concentrations of all variables were significantly linked with gestational age. Levels of bioactive tumor necrosis factor-alpha and sTNFRII showed a parallel rise in the second trimester and a decrease thereafter. Values for sTNFRI and sTNFRII and for these receptors and VCAM-1 were correlated, a weak correlation between bioactive tumor necrosis factor-alpha and sTNFRII was observed, and no correlation between circulating fibronectin and other variables was apparent.

CONCLUSIONS

All variables studied exhibited a characteristic pattern depending on gestational age, which supports the concept of a physiologic role of tumor necrosis factor-alpha in pregnancy.

Review: immunobiology of preeclampsia

Preeclampsia has been recognized clinically since the time of Hippocrates: however its etiology and pathophysiology remain enigmatic. This pregnancy-specific syndrome typically presents in late pregnancy as hypertension, edema, and proteinuria. Investigations over the past 15 years have revealed that preeclampsia is associated with abnormal placentation, reduced placental perfusion, endothelial cell dysfunction, and systemic vasospasm. Since it occurs more commonly in primigravidae and in women with underlying collagen-vascular diseases, an immunological component has long been suspected. Increased prevalence in high-order and molar pregnancies and those associated with increased placental mass suggests that trophoblastic volume and fetal antigen load are correlated with the syndrome. Epidemiological reports indicate that the prevalence of preeclampsia is decreased in women who received heterologous blood transfusions, practiced oral sex, or when a long period of cohabitation preceded an established pregnancy. Conversely, the use of condoms as a primary mode of contraception is associated with a higher risk of preeclampsia. These studies suggest that prior exposure to foreign or paternal antigens imparts a protection against the likelihood of developing preeclampsia. Clinical evidence of cellular and humoral immune dysfunction is associated with the syndrome. Fibrin and complement deposition and "foam" cells in atherosis lesions resemble the histopathology of renal allograft rejection. Relative T-cell, natural killer cell, and neutrophil activation have been reported in preeclampsia and circulating cytokines and antiphospholipid antibodies are more prevalent in preeclampsia than in normal pregnant women. These abnormalities are consistent with the systemic endothelial cell dysfunction that has been postulated as a pathophysiological feature of preeclampsia. While such associations do not prove causality, they suggest testable hypotheses for continued basic and clinical investigation of this major complication of human pregnancy.

TNF alpha concentrations and mRNA expression are increased in preeclamptic placentas

Tumor necrosis factor-alpha (TNF alpha), a cytokine produced mainly by macrophages, is involved in immunoregulation, the modulation of cell growth and differentiation, as well as in the induction of oxygen free radicals. In preeclamptic placentas, lipid peroxides are increased as compared to normal placentas. If TNF alpha was abnormally increased in preeclamptic placentas, it might contribute to the increased oxidative stress and the formation of lipid peroxides. We hypothesized that TNF alpha levels would be higher in preeclamptic than in normal placentas. We determined: (1) the levels of TNF alpha protein in whole placental tissue; (2) the concentrations of TNF alpha protein and lipid peroxides in the medium after 48 h of incubation of whole placental villi; (3) mRNA expression of TNF alpha. Placental TNF alpha protein levels were measured by ELISA, lipid peroxides by a spectrophotometric method specific for peroxides, and TNF alpha mRNA expression by RT-PCR.

RESULTS

(1) TNF alpha tissue levels were significantly higher in preeclamptic than in normal placentas, P < 0.05. (2) Concentrations of both TNF alpha and lipid peroxides were higher in the incubation medium of preeclamptic than normal placentas, P < 0.05. (3) TNF alpha concentrations in the incubation medium were positively correlated with lipid peroxide concentrations, r = 0.608. (4) TNF alpha mRNA was expressed in preeclamptic placentas, but not in normal placentas.

CONCLUSIONS

TNF alpha protein concentrations and mRNA expression are higher in preeclamptic than normal placentas and this is associated with increased lipid peroxidation.

The potential biological and clinical significance of the soluble tumor necrosis factor receptors

The role of TNF receptors (TNF-Rs) is not limited to signal transduction but includes extracellular regulatory functions affecting systemic TNF bioavailability. This review summarizes the regulation of TNF-R shedding and its kinetics, the complex interaction between the soluble receptors and their ligand in vitro and in vivo, and the potential diagnostic, prognostic and therapeutic value of the soluble receptors in malignant, inflammatory, infectious and autoimmune disorders.