Effects of Ureaplasma parvum lipoprotein multiple-banded antigen on pregnancy outcome in mice.

Ureaplasma spp. are members of the family Mycoplasmataceae and have been considered to be associated with chorioamnionitis and preterm delivery. However, it is unclear whether Ureaplasma spp. have virulence factors related to these manifestations. The purpose of the present study was to determine whether the immunogenic protein multiple-banded antigen (MBA) from Ureaplasma parvum is a virulence factor for preterm delivery. We partially purified MBA from a type strain and clinical isolates of U. parvum, and also synthesized a diacylated lipopeptide derived from U. parvum, UPM-1. Using luciferase assays, both MBA-rich fraction MRF and UPM-1 activated the NF-κB pathway via TLR2. UPM-1 upregulated IL-1ß, IL-6, IL-12p35, TNF-α, MIP2, LIX, and iNOS in mouse peritoneal macrophage. MRF or UPM-1 was injected into uteri on day 15 of gestation on pregnant C3H/HeN mice. The intrauterine MRF injection group had a significantly higher incidence of intrauterine fetal death (IUFD; 38.5%) than the control group (14.0%). Interestingly, intrauterine injection of UPM-1 caused preterm deliveries at high concentration (80.0%). In contrast, a low concentration of UPM-1 induced a significantly higher rate of fetal deaths (55.2%) than the control group (14.0%). The placentas of the UPM-1 injection group showed neutrophil infiltration and increased iNOS protein expression. Our data indicate that MBA from the clinical isolate of U. parvum is a potential virulence factor for IUFD and preterm delivery in mice and that the N-terminal diacylated lipopeptide is essential for the initiation of inflammation.

Maternal floor infarction/massive perivillous fibrin deposition: a manifestation of maternal antifetal rejection?

OBJECTIVE: Massive perivillous fibrin deposition (MPFD) and maternal floor infarction (MFI) are related placental lesions often associated with fetal death and fetal growth restriction. A tendency to recur in subsequent pregnancies has been reported. This study was conducted to determine whether this complication of pregnancy could reflect maternal antifetal rejection. METHODS: Pregnancies with MPFD were identified (n = 10). Controls consisted of women with uncomplicated pregnancies who delivered at term without MPFD (n = 175). Second-trimester maternal plasma was analyzed for panel-reactive anti-HLA class I and class II antibodies. The prevalence of chronic chorioamnionitis, villitis of unknown etiology, and plasma cell deciduitis was compared between cases and controls. Immunohistochemistry was performed on available umbilical vein segments from cases with MPFD (n = 4) to determine whether there was evidence of complement activation (C4d deposition). Specific maternal HLA-antibody and fetal HLA-antigen status were also determined in paired specimens (n = 6). Plasma CXCL-10 concentrations were measured in longitudinal samples of cases (n = 28 specimens) and controls (n = 749 specimens) by ELISA. Linear mixed-effects models were used to test for differences in plasma CXCL-10 concentration. RESULTS: (i) The prevalence of plasma cell deciduitis in the placenta was significantly higher in cases with MPFD than in those with uncomplicated term deliveries (40% versus 8.6%, P = 0.01), (ii) patients with MPFD had a significantly higher frequency of maternal anti-HLA class I positivity during the second trimester than those with uncomplicated term deliveries (80% versus 36%, P = 0.01); (iii) strongly positive C4d deposition was observed on umbilical vein endothelium in cases of MPFD, (iv) a specific maternal antibody against fetal HLA antigen class I or II was identified in all cases of MPFD; and 5) the mean maternal plasma concentration of CXCL-10 was higher in patients with evidence of MPFD than in those without evidence of MFPD (P < 0.001). CONCLUSION: A subset of patients with MPFD has evidence of maternal antifetal rejection.

Direct and indirect antigen presentation lead to deletion of donor-specific T cells after in utero hematopoietic cell transplantation in mice.

In utero hematopoietic cell transplantation (IUHCTx) is a promising method to induce donor-specific tolerance but the mechanisms of antigen presentation that educate host T cells and the relative importance of deletion vs regulation in this setting are unknown. We studied the roles of direct and indirect antigen presentation (mediated by donor- and host-derived antigen-presenting cells [APCs], respectively) in a mouse model of IUHCTx. We found that IUHCTx leads to precocious maturation of neonatal host dendritic cells (DCs) and that there is early differentiation of donor-derived DCs, even after transplantation of a stem cell source without mature APCs. We next performed allogeneic IUHCTx into donor-specific T-cell receptor transgenic mice and confirmed that both direct and indirect antigen presentation lead to clonal deletion of effector T cells in chimeras. Deletion did not persist when chimerism was lost. Importantly, although the percentage of regulatory T cells (Tregs) after IUHCTx increased, there was no expansion in Treg numbers. In wild-type mice, there was a similar deletion of effector cells without expansion of donor-specific Tregs. Thus, tolerance induction after IUHCTx depends on both direct and indirect antigen presentation and is secondary to thymic deletion, without de novo Treg induction.

TLR9 provokes inflammation in response to fetal DNA: mechanism for fetal loss in preterm birth and preeclampsia.

Preterm birth, the major cause of neonatal mortality in developed countries, is associated with intrauterine infections and inflammation, although the exact mechanisms underlying this event are unclear. In this study, we show that circulating fetal DNA, which is elevated in pregnancies complicated by preterm labor or preeclampsia, triggers an inflammatory reaction that results in spontaneous preterm birth. Fetal DNA activates NF-κB, shown by IκBα degradation in human PBMCs resulting in production of proinflammatory IL-6. We show that fetal resorption and preterm birth are rapidly induced in mice after i.p. injection of CpG or fetal DNA (300 µg/dam) on gestational day 10-14. In contrast, TLR9(-/-) mice were protected from these effects. Furthermore, this effect was blocked by oral administration of the TLR9 inhibitor chloroquine. Our data therefore provide a novel mechanism for preterm birth and preeclampsia, highlighting TLR9 as a potential therapeutic target for these common disorders of pregnancy.

Anatomical and pathological findings in hearts from fetuses and infants with cardiac manifestations of neonatal lupus.

OBJECTIVE: The autopsy and clinical information on children dying with anti-SSA/Ro-associated cardiac manifestations of neonatal lupus (cardiac NL) were examined to identify patterns of disease, gain insight into pathogenesis and enhance the search for biomarkers and preventive therapies. METHODS: A retrospective analysis evaluating reports from 18 autopsies of cardiac NL cases and clinical data from the Research Registry for Neonatal Lupus was performed. RESULTS: Of the 18 cases with autopsies, 15 had advanced heart block, including 3 who died in the second trimester, 9 in the third trimester and 3 post-natally. Three others died of cardiomyopathy without advanced block, including two dying pre-natally and one after birth. Pathological findings included fibrosis/calcification of the atrioventricular (AV) node, sinoatrial (SA) node and bundle of His, endocardial fibroelastosis (EFE), papillary muscle fibrosis, valvular disease, calcification of the atrial septum and mononuclear pancarditis. There was no association of pathology with the timing of death except that in the third-trimester deaths more valvular disease and/or extensive conduction system abnormalities were observed. Clinical rhythm did not always correlate with pathology of the conduction system, and the pre-mortem echocardiograms did not consistently detect the extent of pathology. CONCLUSION: Fibrosis of the AV node/distal conduction system is the most characteristic histopathological finding. Fibrosis of the SA node and bundle of His, EFE and valve damage are also part of the anti-Ro spectrum of injury. Discordance between echocardiograms and pathology findings should prompt the search for more sensitive methods to accurately study the phenotype of antibody damage.

ß2-Glycoprotein-I based peptide regulate endothelial-cells tissue-factor expression via negative regulation of pGSK3ß expression and reduces experimental-antiphospholipid-syndrome.

Antiphospholipid syndrome (APS) is characterized by thromboembolic phenomena and recurrent fetal loss associated with elevated circulating anti-phospholipid/beta2glycoprotein-I(ß2GPI)-binding-antibodies(Abs). Individual APS patients harbor diverse clusters of circulating anti-ß2GPI Abs, targeting different epitopes on the ß2GPI molecule. Our novel approach was to construct a peptide composed of ß2GPI-ECs-binding-site (phospholipids-membrane), named "EMBI". EMBI exert dual activities: a) At first EMBI prevented ß2GPI ECs binding, thus reduced by 89% the binding of ß2GPI/anti-ß2GPI to the cells in comparison with 9.3% inhibition by EMBI scrambled form (scEMBI). b) Longer exposure of ECs to EMBI resulted in intracellular EMBI penetration which did not prevent ß2GPI/anti-ß2GPI binding to HUVEC. Surprisingly, ß2GPI/anti-ß2GPI did not activate ECs harboring EMBI, illustrated by prevention of E-selectin and tissue factor (TF) expression. The inhibition of TF mRNA transcription was illustrated by quantitative RT-PCR. EMBI decreased the expression of phosphorylated JNK1/2, p38, HSP27 and enhanced phosphorylation of glycogen synthase kinase-3ß (pGSK3ß). Knocking down the GSK3ß expression by siRNA-GSK3ß, reduced the TF expression by ß2GPI/anti-ß2GPI-exposed-HUVEC. In-vivo, EMBI significantly decreased the percentage of fetal loss in naïve mice infused with anti-ß2GPI Abs, p<0.04. Thus, the dual activity of EMBI may introduce EMBI as a potential novel candidate peptide, to treat patients with APS.

Neutralization of LPS or blockage of TLR4 signaling prevents stress-triggered fetal loss in murine pregnancy.

Maternal stress can cause loss of both histocompatible (syngeneic) and histoincompatible (semiallogeneic) embryos in pregnant mice. Stress increases abortogenic Th1 cytokines and reduces levels of anti-abortogenic Th2 cytokines, progesterone levels, and T regulatory cell activity. While physiological levels of interferon-γ promote vascular remodeling at the feto-maternal interface, an overshooting Th1 cytokine response requires a Toll-like receptor (TLR)-mediated "danger signal" such as lipopolysaccharide (LPS). Interestingly, stress can enhance permeability of mucosal membranes to entry of bacterial products and promote transmucosal migration of commensal bacteria. We hypothesized that bacterial component such as LPS may provide the danger signal through which stress triggers maternal immune activation, subsequently resulting in fetal rejection. Blocking the TLR4 receptor for LPS or neutralization of LPS using bactericidal permeability increasing protein abrogate fetal loss due to sonic stress challenge in DBA/2J-mated CBA/J mice. These treatments prevented stress-triggered immune responses in the decidua, upregulated Treg cells, and reduced the frequency of mature dendritic cells in uterine-draining lymph nodes but not in the uterus. Interestingly, anti-TLR4 treatment only partly ameliorated stress-induced endocrine responses, such as increased hypothalamic corticotropin releasing hormone and vasopressin mRNA expression but not decrease of serum progesterone. Galectin-1 knock-out mice were more susceptible to stress-triggered complete implantation failure rather than fetal loss, which was also abolished by LPS neutralization. Insights provided in this paper shed new light on the mechanisms by which stress affects pregnancy outcome and introduce microbial-derived LPS as a mediator within the cascade of stress-triggered immune and endocrine events during pregnancy.

Toll-like receptor signaling in uterine natural killer cells--role in embryonic loss.

Embryonic development is a complex process that is regulated by many cell types and signaling pathways. This review focuses on the role of NK cells and regulatory T-cells (Treg cells) in embryonic loss. Approximately 70% of uterine leukocytes until the time of mid-gestation are found to be CD16(-)CD56(bright) NK cells. This subset of NK cells, along with Treg cells, has been shown to regulate fetal development. We recently found a population of NK cells in the pregnant mouse uterus with a unique CD3(-)CD49b(+)CD25(+)Foxp3(+) phenotype. This review summarizes the studies indicating critical roles for expression of IL-10 by CD3(-)CD49b(+)CD25(+)Foxp3(+) cells and CXCR4 expression on CD16(-)CD56(bright) NK cells in preventing embryonic loss. In addition, the roles of toll-like receptors (TLRs) and CXCR4 in NK cell migration and functional modulation are discussed.

RCAS1 decidual immunoreactivity during stillbirth: immune cell presence and activity.

PROBLEM: Alterations in RCAS1 (a receptor-binding cancer antigen expressed on SiSo cells) expression in the placenta and decidua may be related to the regulation of the process of maternal immune tolerance against fetal antigens. Moreover, it has been demonstrated that the occurrence of the spontaneous beginning of stillbirth is related to a decrease in the placental expression of RCAS1. There are no data currently available on the immune processes in decidua during stillbirth. The aim of this study was to evaluate the RCAS1 immunoreactivity level in decidua and to identify the cytotoxic immune cells present during labor, induced after intrauterine fetal death either with a combination of oxytocin (OT) and prostaglandins or with OT alone; a further objective was to assess the potential impact of these molecular alterations on the effectiveness of stillbirth induction. METHODS: The immunoreactivity of RCAS1, CD3, CD56, CD69, and CD25 was assessed by immunohistochemistry in 31 decidual samples derived from patients in whom the stillbirth occurred before the onset of labor. RESULTS: The RCAS1 immunoreactivity level was higher in a statistically significant manner in decidual tissue samples derived from patients in whom OT alone proved insufficient to induce labor after the diagnosis of intrauterine fetal death but required additionally the use of prostaglandins when compared with samples from women in whom stillbirth was induced successfully with OT alone. However, we did not observe any differences either in CD56 and CD3 positive cell presence or in CD25 and CD69 antigen immunoreactivity in the respective decidua of these two groups of patients. CONCLUSION: The level of RCAS1 in decidua seems to influence the effectiveness of stillbirth induction.

Immunosuppression routed via the kynurenine pathway: a biochemical and pathophysiologic approach.

In the past years, it has been shown that kynurenines pathway is a regulator of both the innate and the adaptive immune responses. Particularly, the initial enzyme of this pathway, indoleamine 2,3-dioxygenase (IDO), is implicated in maintaining tolerance during pregnancy, and also can be expressed in tumors to avoid the immune attack. In this chapter, we will describe how the kynurenine pathway affects the immune system with important implications both in physiology and in pathology. The incorrect activation or blockade suppressive properties of the kynurenine pathway are also implicated in a number of other diseases such as AIDS or autoimmune diseases.

Elevated Th1/Th2 cell ratios in a pregnant woman with a history of RSA, secondary Sjögren's syndrome and rheumatoid arthritis complicated with one fetal demise of twin pregnancy.

PROBLEM: Elevated Th1/Th2 cytokine producing CD3(+)/CD4(+) cell ratios were reported in women with a history of recurrent spontaneous abortion (RSA) and multiple implantation failures. We report, significantly elevated Th1/Th2 cell ratios were noticed in a pregnant woman with twin pregnancies complicated with one fetal demise, who had a history of RSA, secondary Sjögren's syndrome (SS), and rheumatoid arthritis. METHOD OF STUDY: Case report. RESULTS: Peripheral blood Th1/Th2 cell ratios were significantly elevated 3 weeks prior to a fetal demise of twin pregnancies at 20 week gestation. Two weeks after fetal demise, the ratio of intracellular tumor necrosis factor-alpha/interleukin-10 producing CD3(+)/CD4(+) cells in peripheral blood was further increased to three times higher than prior ratio. Elevated Th1/Th2 ratio was down regulated after increasing dose of IVIg treatment. The patient gave birth to a male baby weighing 2650 g at 36 weeks gestation. No serious complications were found in the patient or the baby. CONCLUSION: Systemic inflammatory immune response pre-exists prior to a fetal demise and the degree of inflammatory immune response got worse with a presence of fetal demise in utero. We infer that the placenta is not an immunological barrier to maternal Th1/Th2 immune responses.

Lymphocyte contributions to altered endometrial angiogenesis during early and midgestation fetal loss.

Peri-implantation and midgestational fetal losses reduce potential litter sizes up to 40% in commercial swine. Peri-implantation studies [gestation days (gd)15-23] of porcine RNA from laser capture microdissected uterine lymphocytes and biopsies of mesometrial endometrium and trophoblast previously linked gd21-23 fetal arrest with transcriptional deficits in vascular endothelial growth factor (VEGF) and its regulatory factor, hypoxia inducible factor (HIF)-1alpha, and with elevations in IFN-gamma and TNF-alpha and suggested endometrial lymphocytes played a pivotal, proangiogenic role in fetal survival. Here, we address more comprehensively porcine endometrial angiogenesis by comparing transcription between endometrial endothelium and lymphocytes during early (gd20) and midgestation (gd50) losses and by incorporation of histopathology and protein immunolocalization of VEGF, placenta growth factor (PlGF), VEGF receptor I (VEGFRI), and VEGFRII. In healthy sites, endometrial lymphocytes transcribed more VEGF at gd50 than gd20, and transcripts were more abundant in lymphocytes than in endothelium or trophoblast. Arterial endothelial cells showed the most abundant transcription of PlGF. With fetal arrest, maternal transcripts for VEGF but not PlGF dropped, and fetal transcripts remained relatively stable. Maternal and fetal HIF-1alpha transcription declined. Lymphocytes preferentially transcribed VEGFRI over VEGFRII, and endometrial arterial endothelium and trophoblast preferentially transcribed VEGFRII. IFN-gamma and TNF-alpha transcripts were present in gd20 and gd50 healthy- and arresting-implantation sites. gd20 arrest was associated with greater transcription of IFN-gamma than TNF-alpha in maternal and fetal tissues. At gd50, this was reversed. Endometrial, vascular pathology was evident only at gd50. These data suggest the critical importance for lymphocyte-driven endometrial angiogenesis, which extends to midgestation.

A review of gene expression in porcine endometrial lymphocytes, endothelium and trophoblast during pregnancy success and failure.

Meat pig breeds used commercially in North America lose significant numbers of genetically-normal fetuses in the peri-implantation (attachment) period and at mid-gestation (day 50 of the 114 day gestation interval). Fetal demand that is in excess to the placental blood supply is thought to underlie these waves of fetal loss. In many species, the endometrium of early normal pregnancy is enriched in innate immune cells, particularly uterine natural killer (uNK) cells. In pigs, a species with epitheliochorial placentation, conceptuses mediate about a three-fold enrichment in uNK cells at attachment sites but the functions of these cells are unknown. In species with hemochorial placentation, uNK cells are highly enriched during the process of decidualization and promote endometrial angiogenesis. We have conducted molecular analyses using pure samples of endometrial lymphocytes or endothelium and trophoblast from healthy and arresting conceptus attachment sites in Yorkshire gilts immediately post-attachment [gestation day (GD) 20] and at mid pregnancy (GD50). In healthy sites, angiogenesis was more robustly promoted by lymphocytes than by trophoblasts. An early sign of impending fetal arrest was loss of vascular endothelial growth factor (VEGF) transcription from the lymphocytes and elevation in transcription of the pro-inflammatory gene Interferon (IFN)-gamma. We have postulated that newly differentiated endometrial endothelial cells, not fetal trophoblasts, are damaged by the maternal withdrawal of vascular support and onset of inflammation and that this endometrial damage contributes significantly to peri-implantation fetal death.

Presence of IgE cells in human placenta is independent of malaria infection or chorioamnionitis.

We have shown previously that numerous IgE(+) macrophage-like cells are present in the villous stroma of full term placenta and that there was no difference in the amount of IgE(+) cells between allergic and non-allergic mothers. The presence of such an abundant number of IgE(+) cells in the placenta in allergic as well as non-allergic women suggests that the IgE is of some importance for a successful pregnancy outcome. Here we have investigated the IgE-pattern in 59 placentas from second and third trimesters from Sweden with different degrees of chorioamnionitis and 27 full term placentas from Ghana with and without malaria parasites. The immunohistochemical staining pattern for IgE looked similar to our previous study, with the IgE located on Hofbauer-like cells. We could not find any difference in the amount or distribution of IgE(+) cells between malaria-infected and non-infected placentas, nor between different degrees of chorioamnionitis. The IgE score in the placenta did not correlate with the levels of IgE in maternal serum or plasma. However, the IgE score was significantly higher in second- compared to third-trimester placentas (P = 0.03). This might reflect a maturation time-point in the fetus and in the intrauterine environment during the second trimester, or it might be associated with the increased number of intrauterine fetal deaths in the second trimester.

Placenta-derived soluble MHC class I chain-related molecules down-regulate NKG2D receptor on peripheral blood mononuclear cells during human pregnancy: a possible novel immune escape mechanism for fetal survival.

Mammalian pregnancy is an intriguing immunological phenomenon where the semiallogeneic fetus is not rejected. Tolerance toward the fetus involves a number of mechanisms associated with modifications of the immune status of the mother. In this study, we strongly suggest a novel mechanism for fetal evasion of maternal immune attack, based on the engagement and down-regulation of the activating NK cell receptor NKG2D on PBMC by soluble MHC class I chain-related proteins A and B (collectively termed MIC). A similar immune escape pathway was previously described in tumors. We found that MIC mRNA was constitutively expressed by human placenta and could be up-regulated upon heat shock treatment. Our immunomorphologic studies showed that the MIC expression in placenta was restricted to the syncytiotrophoblast. Immunoelectron microscopy revealed a dual MIC expression in the syncytiotrophoblast: on the apical and basal cell membrane and in cytoplasmic vacuoles as MIC-loaded microvesicles/exosomes. Soluble MIC molecules were present at elevated levels in maternal blood throughout normal pregnancy and were released by placental explants in vitro. Simultaneously, the cell surface NKG2D expression on maternal PBMC was down-regulated compared with nonpregnant controls. The soluble MIC molecules in pregnancy serum were able to interact with NKG2D and down-regulate the receptor on PBMC from healthy donors, with the consequent inhibition of the NKG2D-dependent cytotoxic response. These findings suggest a new physiological mechanism of silencing the maternal immune system that promotes fetal allograft immune escape and supports the view of the placenta as an immunoregulatory organ.

TNF-alpha-mediated stress-induced early pregnancy loss: a possible role of leukemia inhibitory factor.

BACKGROUND: Leukemia inhibitory factor (LIF) is at present suggested to be essential for implantation in mammals. In parallel, the possibility that it may also be involved in the pathogenesis of stress-induced early embryonic death seems to emerge from studies, which addressed the embryotoxic potential of another cytokine, tumor necrosis factor-alpha (TNF-alpha). In this brief review, we discuss this possibility based on these studies as well as on those addressing TNF-alpha and LIF signaling. METHODS: Existing data were reviewed critically. RESULTS: Data summarized in this review suggest that: (1) TNF-alpha may act as a mediator of stress-induced early embryonic death, (2) TNF-alpha-mediated early embryonic death induced by some detrimental stimuli may be attributed to a dysfunction of mechanisms, which are critical for the ability of the uterus to become receptive to blastocysts, allowing implantation, (3) one such mechanism was shown to be associated with LIF signaling in uterine cells, and (4) TNF-alpha seems to have the potential to affect LIF signaling. CONCLUSION: Data presented in the this review suggest LIF as a good candidate for further studies addressing molecular mechanisms underlying stress-induced early embryonic death.

[Foetomaternal erythrocyte incompatibilities: from immunohaematologic surveillance of pregnant women to haemolytic disease of the newborn]. / Incompatibilités foetomaternelles érythrocytaires (IFME): de la surveillance immunohématologique des femmes enceintes à la maladie hémolytique du nouveau-né (MHNN).

Despite the generalization of prevention measures against foetomaternal alloimmunization with anti-D immunoprophylaxis since 1970s, retrospectively 30 years later, its complications (new-born child's severe haemolytic disease, foetal death by anemia or nuclear icterus by bilirubin encephalopathy) have not disappeared. At the same time, alloimmunizations against antigens other than D increase with no possible prevention. As part of the set up in France of regional files analysing and making an inventory of serious foetomaternal incompatibilities requiring in utero or neonatal transfusion, we felt the need to synthesize current data, biological profiles (early screening of erythrocytic alloimmunization and its follow up during pregnancy, father's immunohaematologic status, evaluation of in utero immune haemolysis and impact of new non invasive techniques of diagnosis-RH1 foetal genotypage from ADN foetal of RH1--mothers' maternal plasma), clinical and paraclinical data (evaluation of foetal haemolysis by echography, recording of foetal movements and foetal cardiac rhythm), therapeutic indicators (in utero foetal transfusions or exsanguinotransfusions, neo and postnatal transfusions or exsanguinotransfusions, induced premature labour, newborn's intensive continue phototherapy and Rhesus immunoprophylaxis) in order to enable medical and paramedical professionals to carry out the specific supervision of pregnancies with foetomaternal incompatibility, the in utero, neo- and postnatal treatment of child and the efficient therapeutic prevention of anti-D alloimmunization, in a cooperative way.

Systemic and placental productions of tumor necrosis factor contribute to induce fetal mortality in mice acutely infected with Trypanosoma cruzi.

Blood levels and placental productions of IFN-gamma and TNF, known to be harmful for pregnancy, were determined in pregnant mice acutely infected with Trypanosoma cruzi and suffering massive fetal losses without congenital infection. INF-gamma was detected mainly at day 9 and TNF at days 17 and 19 of pregnancy in plasma of infected mice. TNF levels were significantly correlated to the percentages of dead fetuses. Placental cells produced TNF but not IFN-gamma, and addition of T. cruzi lysate to such cells strongly stimulated TNF production. Treatment of infected mice with pentoxifylline, known to decrease IFN-gamma production and to inhibit the TNF-alpha gene transcription, reduced the placental production of TNF, and the fetal mortality in comparison to control animals. Altogether these result suggest that TNF produced at systemic and placental levels plays a role in the fetal mortality induced in mice acutely infected with T. cruzi.

The increased lysis of fetal cells in the mother after pregnancies complicated by pre-eclampsia or HELLP syndrome is not the result of a specific anti-fetal cytotoxicity of the mother.

PROBLEM: In pregnancies complicated by pre-eclampsia or hemolytisis elevated liver enzymes, low platelets (HELLP) syndrome, an increase of fetal DNA in the maternal serum indicates an increased lysis of fetal cells. Whether this cytolysis is the cause or the result of an increased specific cytotoxicity against the fetal cells is not yet known. METHODS: Ten mothers after healthy pregnancy, eight mothers after pregnancy complicated by prematurity (GA < 37 weeks), and eight mothers with pregnancies complicated by pre-eclampsia or HELLP syndrome and their male children were enrolled in the study. Fetally derived DNA in the maternal serum and the specific anti-fetal cytotoxicity of the maternal lymphocytes were measured. RESULTS: Detection of fetal DNA in maternal serum was significantly associated with pre-eclampsia/HELLP syndrome but not with anti-fetal cytotoxicity of the maternal lymphocytes. CONCLUSION: The cytolysis of fetal cells in mothers after pregnancies complicated by pre-eclampsia/HELLP syndrome is neither the reason for nor the result of an increased specific anti-fetal cytotoxicity.

TNF-alpha in pregnancy loss and embryo maldevelopment: a mediator of detrimental stimuli or a protector of the fetoplacental unit?

PURPOSE: Tumor necrosis factor alpha (TNF-alpha), a multifunctional cytokine, has been identified in the ovary, oviduct, uterus, and placenta, and is expressed in embryonic tissues. For many years TNF-alpha was mainly considered to be a cytokine involved in triggering immunological pregnancy loss and as a mediator of various embryopathic stresses. However, data collected during the last decade has characterized TNF-alpha not only as a powerful activator of apoptotic, but also antiapoptotic signaling cascades, as well as revealed its regulatory role in cell proliferation. This review summarizes and conceptualizes the studies addressing TNF-alpha-activated intracellular signaling and the possible functional role of TNF-alpha in embryonic development. METHODS: Studies addressing the role of TNF-alpha in intercellular signaling, in vivo studies addressing the functional role TNF-alpha in spontaneous and induced pregnancy loss, and studies addressing the role of TNF-alpha in fetal malformations were reviewed. Comparative studies in TNF-alpha knockout and TNF-alpha positive mice were performed to evaluate embryonic death, structural anomalies in fetuses, the degree of apoptosis and cell proliferation, and the activity of molecules such as caspases 3 and 8, the NF-kappaB, (RelA), IkappaBalpha in some target embryonic organs shortly after exposure to embryopathic stresses. RESULTS: It is proposed that the possible essential function of TNF-alpha may be to prevent the birth of offspring with structural anomalies. CONCLUSIONS: TNF-alpha will boost death signaling to kill the embryo if initial events (damages) triggered by detrimental stimuli may culminate in structural anomalies, and stimulate protective mechanisms if the repair of these damages may prevent maldevelopment.