Protective effect of N-acetylcysteine against fetal death and preterm labor induced by maternal inflammation

Glutathione prevents preterm parturition and fetal death by targeting macrophage-induced reactive oxygen species production in the myometrium

Preterm birth is an inflammatory process resulting from the massive infiltration of innate immune cells and the production of proinflammatory cytokines in the myometrium. However, proinflammatory cytokines, which induce labor in vivo, fail to induce labor-associated features in human myometrial cells (MCs). We thus aimed to investigate if reactive oxygen species (ROS) production could be the missing step between immune cell activation and MC response. Indeed, we found that ROS production is increased in the human preterm laboring myometrium (27% ROS producing cells, respectively, versus 2% in nonlaboring controls), with 90% ROS production in macrophages. Using LPS-stimulated myometrial samples and cell coculture experiments, we demonstrated that ROS production is required for labor onset. Furthermore, we showed that ROS are required first in the NADPH oxidase (NADPHox)-2/NF-κB-dependent macrophage response to inflammatory stimuli but, more importantly, to trigger macrophage-induced MCs transactivation. Remarkably, in a murine model of LPS-induced preterm labor (inducing delivery within 17 hours, with no pup survival), cotreatment with glutathione delayed labor onset up to 94 hours and prevented in utero fetal distress, allowing 46% pups to survive. These results suggest that targeting ROS production with the macrophage-permeable antioxidant glutathione could constitute a promising strategy to prevent preterm birth.

Effects of subcutaneous LPS injection on gestational length and intrauterine and neonatal mortality in mice

BACKGROUND

Infection during pregnancy can predispose offspring to develop various psychiatric disorders such as depression in later life. In order to investigate the potential mechanisms underlying these associations, animal models of maternal infection have been employed. As such, lipopolysaccharide (LPS) has been commonly used to mimic a bacterial infection in pregnant mice.

OBJECTIVE

The original aim of our study was to investigate the effects of different doses of subcutaneous LPS administration on affective behavior in adult mouse offspring. In the present paper, however, we report that subcutaneous LPS administration has a profound impact on gestational length, litter size, and perinatal mortality in the offspring, even at a relatively low dose.

METHODS

Pregnant mice were randomly divided into 3 groups, receiving either a high (2 mg/kg) or a low (0.5 mg/kg) dose of LPS or phosphate-buffered saline by means of subcutaneous injection. Subsequently, the effects on gestational length, litter size, and perinatal mortality in the offspring were assessed.

RESULTS

After subcutaneous injection with a high dose of LPS, we observed a significant decrease in gestational length and an increase in neonatal mortality. When the low dose was administered, a tendency towards a reduced litter size was observed, most likely reflecting increased intrauterine mortality in response to prenatal maternal LPS exposure.

CONCLUSIONS

We showed that subcutaneous administration of 2 mg/kg LPS to pregnant mice in the last phase of gestation should be avoided because of high offspring mortality rates, whereas subcutaneous injection of 0.5 mg/kg LPS seems to result in reabsorption of the fetuses.

Effects of maternal LPS exposure during pregnancy on metabolic phenotypes in female offspring

It is increasingly recognized that intra-uterine growth restriction (IUGR) is associated with an increased risk of metabolic disorders in late life. Previous studies showed that mice exposed to LPS in late gestation induced fetal IUGR. The present study investigated the effects of maternal LPS exposure during pregnancy on metabolic phenotypes in female adult offspring. Pregnant mice were intraperitoneally injected with LPS (50 µg/kg) daily from gestational day (GD)15 to GD17. After lactation, female pups were fed with standard-chow diets (SD) or high-fat diets (HFD). Glucose tolerance test (GTT) and insulin tolerance test (ITT) were assessed 8 and 12 weeks after diet intervention. Hepatic triglyceride content was examined 12 weeks after diet intervention. As expected, maternal LPS exposure during pregnancy resulted in fetal IUGR. Although there was an increasing trend on fat mass in female offspring whose dams were exposed to LPS during pregnancy, maternal LPS exposure during pregnancy did not elevate the levels of fasting blood glucose and serum insulin and hepatic triglyceride content in female adult offspring. Moreover, maternal LPS exposure during pregnancy did not alter insulin sensitivity in adipose tissue and liver in female adult offspring. Further analysis showed that maternal LPS exposure during pregnancy did not exacerbate HFD-induced glucose tolerance and insulin resistance in female adult offspring. In addition, maternal LPS exposure during pregnancy did not aggravate HFD-induced elevation of hepatic triglyceride content in female adult offspring. In conclusion, LPS-induced IUGR does not alter metabolic phenotypes in adulthood.

Orally administered melatonin prevents lipopolysaccharide-induced neural tube defects in mice

Lipopolysaccharide (LPS) has been associated with adverse pregnant outcomes, including fetal demise, intra-uterine growth restriction (IUGR), neural tube defects (NTDs) and preterm delivery in rodent animals. Previous studies demonstrated that melatonin protected against LPS-induced fetal demise, IUGR and preterm delivery. The aim of the present study was to investigate the effects of melatonin on LPS-induced NTDs. All pregnant mice except controls were intraperitoneally injected with LPS (25 µg/kg) daily from gestational day (GD)8 to GD12. Some pregnant mice were orally administered with melatonin (MT, 50 mg/kg) before each LPS injection. A five-day LPS injection resulted in 27.5% of fetuses with anencephaly, exencephaly or encephalomeningocele. Additional experiment showed that maternal LPS exposure significantly down-regulated placental proton-coupled folate transporter (pcft) and disturbed folate transport from maternal circulation through the placentas into the fetus. Interestingly, melatonin significantly attenuated LPS-induced down-regulation of placental pcft. Moreover, melatonin markedly improved the transport of folate from maternal circulation through the placentas into the fetus. Correspondingly, orally administered melatonin reduced the incidence of LPS-induced anencephaly, exencephaly or encephalomeningocele. Taken together, these results suggest that orally administered melatonin prevents LPS-induced NTDs through alleviating LPS-induced disturbance of folate transport from maternal circulation through the placenta into the fetus.

Nicotine, an α7 nAChR agonist, reduces lipopolysaccharide-induced inflammatory responses and protects fetuses in pregnant rats

OBJECTIVE

The objective of the study was to examine the effects of nicotine, an α7 nicotinic acetylcholine receptor agonist, on lipopolysaccharide (LPS)-induced inflammatory responses in rats during pregnancy.

STUDY DESIGN

Pregnant Sprague Dawley rats were randomly divided into groups (n = 6 rats/group): group 1 rats each received a single intraperitoneal injection of LPS (25 μg/kg) on gestation day 16; group 2 rats were first pretreated with nicotine (1 mg/kg per day, subcutaneously) on gestation days 14 and 15 and then were treated with single injections of LPS on gestational day 16; group 3 rats were treated with the vehicle (saline) used for groups 2 and 3 (controls). Maternal blood was collected at 6 hours and 24 hours after LPS and vehicle treatments and assayed for tumor necrosis factor (TNF)-α, interleukin-6 (IL-6), and interleukin-10 (IL-10). In addition, the number of live pups and pup weights were obtained at the time of delivery.

RESULTS

LPS treatment significantly (P < .001) elevates maternal blood levels of TNF-α and IL-6 but not IL-10 (P > .05). Nicotine treatment significantly reduces LPS-induced TNF-α and IL-6 concentrations (P < .001) but does not change (P > .05) IL-10 levels. The number of live pups in the LPS group are significantly lower (P < .001) than the vehicle treated controls, and nicotine treatment significantly (P < .011) reverses this change. Similarly, fetal weights are lower following LPS (P < .016) and higher (P < .024) in the group treated with nicotine plus LPS.

CONCLUSION

Nicotine reduces the LPS-induced inflammatory responses and rescues the fetus in rats during pregnancy. Thus, nicotine exerts dramatic antiinflammatory effects. These observations have important implications for control of inflammatory responses during pregnancy.

Protective effect of nuclear factor E2-related factor 2 on inflammatory cytokine response to brominated diphenyl ether-47 in the HTR-8/SVneo human first trimester extravillous trophoblast cell line

Polybrominated diphenyl ethers (PBDEs) are widely used flame retardants, and BDE-47 is a prevalent PBDE congener detected in human tissues. Exposure to PBDEs has been linked to adverse pregnancy outcomes in humans. Although the underlying mechanisms of adverse birth outcomes are poorly understood, critical roles for oxidative stress and inflammation are implicated. The present study investigated antioxidant responses in a human extravillous trophoblast cell line, HTR-8/SVneo, and examined the role of nuclear factor E2-related factor 2 (Nrf2), an antioxidative transcription factor, in BDE-47-induced inflammatory responses in the cells. Treatment of HTR-8/SVneo cells with 5, 10, 15, and 20μM BDE-47 for 24h increased intracellular glutathione (GSH) levels compared to solvent control. Treatment of HTR-8/SVneo cells with 20μM BDE-47 for 24h induced the antioxidant response element (ARE) activity, indicating Nrf2 transactivation by BDE-47 treatment, and resulted in differential expression of redox-sensitive genes compared to solvent control. Pretreatment with tert-butyl hydroquinone (tBHQ) or sulforaphane, known Nrf2 inducers, reduced BDE-47-stimulated IL-6 release with increased ARE reporter activity, reduced nuclear factor kappa B (NF-κB) reporter activity, increased GSH production, and stimulated expression of antioxidant genes compared to non-Nrf2 inducer pretreated groups, suggesting that Nrf2 may play a protective role against BDE-47-mediated inflammatory responses in HTR-8/SVneo cells. These results suggest that Nrf2 activation significantly attenuated BDE-47-induced IL-6 release by augmentation of cellular antioxidative system via upregulation of Nrf2 signaling pathways, and that Nrf2 induction may be a potential therapeutic target to reduce adverse pregnancy outcomes associated with toxicant-induced oxidative stress and inflammation.

Effects of cytokine-suppressive anti-inflammatory drugs on inflammatory activation in ex vivo human and ovine fetal membranes

Intrauterine infection and inflammation are responsible for the majority of early (<32 weeks) spontaneous preterm births (PTBs). Anti-inflammatory agents, delivered intra-amniotically together with antibiotics, may be an effective strategy for preventing PTB. In this study, the effects of four cytokine-suppressive anti-inflammatory drugs (CSAIDs:N-acetyl cysteine (NAC), SB239063, TPCA-1 and NEMO binding domain inhibitor (NBDI)) were assessed on human and ovine gestational membrane inflammation. Full-thickness membranes were collected from healthy, term, human placentas delivered by Caesarean section (n=5). Using a Transwell model, they were stimulatedex vivowith γ-irradiation-killedEscherichia coliapplied to the amniotic face. Membranes from near-term, ovine placentas were stimulatedin uterowith lipopolysaccharide,Ureaplasma parvumor saline control and subjected to explant culture. The effects of treatment with CSAIDs or vehicle (1% DMSO) on accumulation of PGE2and cytokines (human interleukin 6 (IL6), IL10 and TNFα; ovine IL8 (oIL8)) were assessed in conditioned media at various time points (3–20 h). In human membranes, the IKKβ inhibitor TPCA-1 (7 μM) and p38 MAPK inhibitor SB239063 (20 μM) administered to the amniotic compartment were the most effective in inhibiting accumulation of cytokines and PGE2in the fetal compartment. NAC (10 mM) inhibited accumulation of PGE2and IL10 only; NBDI (10 μM) had no significant effect. In addition to the fetal compartment, SB239063 also exerted consistent and significant inhibitory effects in the maternal compartment. TPCA-1 and SB239063 suppressed oIL8 production, while all CSAIDs tested suppressed ovine PGE2production. These results support the further investigation of intra-amniotically delivered CSAIDs for the prevention of inflammation-mediated PTB.

Targeting Neovascularization in Ischemic Retinopathy: Recent Advances

Pathological retinal neovascularization (RNV) is a common micro-vascular complication in several retinal diseases including retinopathy of prematurity, diabetic retinopathy, age-related macular degeneration and central vein occlusion. The current therapeutic modalities of RNV are invasive and although they may slow or halt the progression of the disease they are unlikely to restore normal acuity. Therefore, there is an urgent need to develop treatment modalities, which are less invasive and therefore associated with fewer procedural complications and systemic side effects. This review article summarizes our understanding of the pathophysiology and current treatment of RNV in ischemic retinopathies; lists potential therapeutic targets; and provides a framework for the development of future treatment modalities.

Folic acid protects against lipopolysaccharide-induced preterm delivery and intrauterine growth restriction through its anti-inflammatory effect in mice

Increasing evidence demonstrates that maternal folic acid (FA) supplementation during pregnancy reduces the risk of neural tube defects, but whether FA prevents preterm delivery and intrauterine growth restriction (IUGR) remains obscure. Previous studies showed that maternal lipopolysaccharide (LPS) exposure induces preterm delivery, fetal death and IUGR in rodent animals. The aim of this study was to investigate the effects of FA on LPS-induced preterm delivery, fetal death and IUGR in mice. Some pregnant mice were orally administered with FA (0.6, 3 or 15 mg/kg) 1 h before LPS injection. As expected, a high dose of LPS (300 μg/kg, i.p.) on gestational day 15 (GD15) caused 100% of dams to deliver before GD18 and 89.3% of fetuses dead. A low dose of LPS (75 μg/kg, i.p.) daily from GD15 to GD17 resulted in IUGR. Interestingly, pretreatment with FA prevented LPS-induced preterm delivery and fetal death. In addition, FA significantly attenuated LPS-induced IUGR. Further experiments showed that FA inhibited LPS-induced activation of nuclear factor kappa B (NF-κB) in mouse placentas. Moreover, FA suppressed LPS-induced NF-κB activation in human trophoblast cell line JEG-3. Correspondingly, FA significantly attenuated LPS-induced upregulation of cyclooxygenase (COX)-2 in mouse placentas. In addition, FA significantly reduced the levels of interleukin (IL)-6 and keratinocyte-derived cytokine (KC) in amniotic fluid of LPS-treated mice. Collectively, maternal FA supplementation during pregnancy protects against LPS-induced preterm delivery, fetal death and IUGR through its anti-inflammatory effects.

Involvement of reactive oxygen species in brominated diphenyl ether-47-induced inflammatory cytokine release from human extravillous trophoblasts in vitro

Polybrominated diphenyl ethers (PBDEs) are widely used flame retardant compounds. Brominated diphenyl ether (BDE)-47 is one of the most prevalent PBDE congeners found in human breast milk, serum and placenta. Despite the presence of PBDEs in human placenta, effects of PBDEs on placental cell function are poorly understood. The present study investigated BDE-47-induced reactive oxygen species (ROS) formation and its role in BDE-47-stimulated proinflammatory cytokine release in a first trimester human extravillous trophoblast cell line, HTR-8/SVneo. Exposure of HTR-8/SVneo cells for 4h to 20μM BDE-47 increased ROS generation 1.7 fold as measured by the dichlorofluorescein (DCF) assay. Likewise, superoxide anion production increased approximately 5 fold at 10 and 15μM and 9 fold at 20μM BDE-47 with a 1-h exposure, as measured by cytochrome c reduction. BDE-47 (10, 15 and 20μM) decreased the mitochondrial membrane potential by 47-64.5% at 4, 8 and 24h as assessed with the fluorescent probe Rh123. Treatment with 15 and 20μM BDE-47 stimulated cellular release and mRNA expression of IL-6 and IL-8 after 12 and 24-h exposures: the greatest increases were a 35-fold increased mRNA expression at 12h and a 12-fold increased protein concentration at 24h for IL-6. Antioxidant treatments (deferoxamine mesylate, (±)α-tocopherol, or tempol) suppressed BDE-47-stimulated IL-6 release by 54.1%, 56.3% and 37.7%, respectively, implicating a role for ROS in the regulation of inflammatory pathways in HTR-8/SVneo cells. Solvent (DMSO) controls exhibited statistically significantly decreased responses compared with non-treated controls for IL-6 release and IL-8 mRNA expression, but these responses were not consistent across experiments and times. Nonetheless, it is possible that DMSO (used to dissolve BDE-47) may have attenuated the stimulatory actions of BDE-47 on cytokine responses. Because abnormal activation of proinflammatory responses can disrupt trophoblast functions necessary for placental development and successful pregnancy, further investigation is warranted of the impact of ROS and BDE-47 on trophoblast cytokine responses.

Convergence of genetic and environmental factors on parvalbumin-positive interneurons in schizophrenia

Schizophrenia etiology is thought to involve an interaction between genetic and environmental factors during postnatal brain development. However, there is a fundamental gap in our understanding of the molecular mechanisms by which environmental factors interact with genetic susceptibility to trigger symptom onset and disease progression. In this review, we summarize the most recent findings implicating oxidative stress as one mechanism by which environmental insults, especially early life social stress, impact the development of schizophrenia. Based on a review of the literature and the results of our own animal model, we suggest that environmental stressors such as social isolation render parvalbumin-positive interneurons (PVIs) vulnerable to oxidative stress. We previously reported that social isolation stress exacerbates many of the schizophrenia-like phenotypes seen in a conditional genetic mouse model in which NMDA receptors (NMDARs) are selectively ablated in half of cortical and hippocampal interneurons during early postnatal development (Belforte et al., 2010). We have since revealed that this social isolation-induced effect is caused by impairments in the antioxidant defense capacity in the PVIs in which NMDARs are ablated. We propose that this effect is mediated by the down-regulation of PGC-1α, a master regulator of mitochondrial energy metabolism and anti-oxidant defense, following the deletion of NMDARs (Jiang et al., 2013). Other potential molecular mechanisms underlying redox dysfunction upon gene and environmental interaction will be discussed, with a focus on the unique properties of PVIs.

Prenatal immune activation interacts with stress and corticosterone exposure later in life to modulate N-methyl-D-aspartate receptor synaptic function and plasticity

Prenatal infection is an environmental risk factor for schizophrenia while later in life, stressful events have been associated with the onset and severity of psychosis. Recent findings on the impact of stress on the N-methyl-d-aspartate receptor (NMDAR), of which hypofunctioning is implicated in schizophrenia, suggest changes in stress-induced regulation of the glutamatergic system may be related to the pathogenesis of schizophrenia. Our study aimed to test whether prenatal immune activation could interact with stress at adolescence to alter NMDAR function. We used offspring from rat dams administered bacterial lipopolysaccharide (LPS) during pregnancy (gestational days 15 and 16), an animal model expressing schizophrenia-related behavioural phenotypes. Using electrophysiological techniques, we investigated effects of stress and the stress hormone corticosterone (Cort) on NMDAR-mediated synaptic function and long-term depression (LTD) in hippocampal CA1 slices from these adolescent (aged 28-39 d) male offspring. In prenatal LPS offspring, NMDAR-mediated synaptic function and LTD were reduced and abolished, respectively, compared to prenatal saline controls. Notably, in vivo stress and in vitro Cort treatment facilitated LTD in slices from prenatal LPS rats but not prenatal saline controls. Finally, Cort enhanced NMDAR-mediated synaptic function in slices from prenatal LPS rats only. We conclude that prenatal immune activation results in NMDAR hypofunction in the hippocampus of adolescent rats but also increases responsiveness of NMDAR-mediated synaptic function and LTD towards stress. Prenatal infection could confer susceptibility to schizophrenia through modification of hippocampal NMDAR function, with hypofunction in resting conditions and heightened responsiveness to stress, thus impacting the development of the disorder.

Synergistic effects of pyrrolizidine alkaloids and lipopolysaccharide on preterm delivery and intrauterine fetal death in mice

Preterm birth is the leading cause of death for newborn infants, and lipopolysaccharide (LPS) is commonly used to induce preterm delivery in experimental animals. Pyrrolizidine alkaloids (PAs) are widespread and occur in foods, herbs, and other plants. This study was to investigate the synergistic effects of LPS and two representative PAs, retrorsine (RTS) and monocrotaline (MCT), on preterm delivery and fetal death. Pregnant Kunming mice were divided into seven groups: control, RTS, MCT, LPS, RTS+LPS and two MCT+LPS groups. Animals in PAs and PAs+LPS groups were dosed intragastrically with RTS (10mg/kg) or MCT (20 mg/kg or 60 mg/kg) from gestational day (GD) 9 to GD16; mice given LPS were injected intraperitoneally with 150 μg/kg on GD15.5. Latencies to delivery, numbers of pups live and dead at birth were recorded, and livers of live neonates were collected. The incidence of LPS-induced preterm birth was enhanced in dams pretreated with MCT, and combination of PAs and LPS increased fetal mortality from PAs. The enhancement of LPS-induced preterm delivery and fetal demise in animals exposed chronically to PAs and other substances found in foods and beverages consumed widely by humans merits further focused investigation.

Developmental neuroinflammation and schizophrenia

There is increasing interest in and evidence for altered immune factors in the etiology and pathophysiology of schizophrenia. Stimulated by various epidemiological findings reporting elevated risk of schizophrenia following prenatal exposure to infection, one line of current research aims to explore the potential contribution of immune-mediated disruption of early brain development in the precipitation of long-term psychotic disease. Since the initial formulation of the "prenatal cytokine hypothesis" more than a decade ago, extensive epidemiological research and remarkable advances in modeling prenatal immune activation effects in animal models have provided strong support for this hypothesis by underscoring the critical role of cytokine-associated inflammatory events, together with downstream pathophysiological processes such as oxidative stress, hypoferremia and zinc deficiency, in mediating the short- and long-term neurodevelopmental effects of prenatal infection. Longitudinal studies in animal models further indicate that infection-induced developmental neuroinflammation may be pathologically relevant beyond the antenatal and neonatal periods, and may contribute to disease progression associated with the gradual development of full-blown schizophrenic disease. According to this scenario, exposure to prenatal immune challenge primes early pre- and postnatal alterations in peripheral and central inflammatory response systems, which in turn may disrupt the normal development and maturation of neuronal systems from juvenile to adult stages of life. Such developmental neuroinflammation may adversely affect processes that are pivotal for normal brain maturation, including myelination, synaptic pruning, and neuronal remodeling, all of which occur to a great extent during postnatal brain maturation. Undoubtedly, our understanding of the role of developmental neuroinflammation in progressive brain changes relevant to schizophrenia is still in infancy. Identification of these mechanisms would be highly warranted because they may represent a valuable target to attenuate or even prevent the emergence of full-blown brain and behavioral pathology, especially in individuals with a history of prenatal complications such as in-utero exposure to infection and/or inflammation.

Prophylactic maternal N-acetylcysteine in rats prevents maternal inflammation-induced offspring cerebral injury shown on magnetic resonance imaging

OBJECTIVE

Maternal infection or inflammation may induce fetal inflammatory responses associated with fetal injury and cerebral palsy. We sought to assess the inflammation-associated neuroprotective potential of prophylactic N-acetyl-cysteine (NAC). We examined the effect of NAC on prevention of maternal lipopolysaccharide (LPS)-induced neonatal brain injury using magnetic resonance imaging.

STUDY DESIGN

Pregnant Sprague Dawley dams (n = 5-8) at embryonic day 18 received intraperitoneal injection of LPS or saline at time 0. Animals were randomized to receive 2 intravenous injections of NAC or saline (time -30 and 120 minutes). Pups were delivered spontaneously and allowed to mature until postnatal day 25. Female offspring were examined by magnetic resonance brain imaging and analyzed using voxel-based analysis after spatial normalization. T2 relaxation time was used to assess white matter injury and diffusion tensor imaging for apparent diffusion coefficient (ADC) to assess white and gray matter injury.

RESULTS

Offspring of LPS-treated dams exhibited significantly increased T2 levels and increased ADC levels in white and gray matter (eg, hypothalamus, motor cortex, corpus callosum, thalamus, hippocampus), consistent with diffuse cerebral injury. In contrast, offspring of NAC-treated LPS dams demonstrated similar T2 and ADC levels as control in both white and gray matter.

CONCLUSION

Maternal NAC treatment significantly reduced evidence of neonatal brain injury associated with maternal LPS. These studies suggest that maternal NAC therapy may be effective in human deliveries associated with maternal/fetal inflammation.

Vitamin D elicits anti-inflammatory response, inhibits contractile-associated proteins, and modulates Toll-like receptors in human myometrial cells

Infection during pregnancy triggers inflammation, which can increase myometrial contractions and the risk of premature labor and delivery. In this study, we assessed the effects of vitamin D, an anti-inflammatory ligand on cytokines, chemokines, toll-like receptors, and contractile-associated proteins on immortalized human myometrial smooth muscle (UtSM) cells stimulated with lipopolysaccharide (LPS), a bacterial endotoxin, or interleukin (IL)-1β and measured Toll-like receptor (TLR)-10 expression in pregnant myometrial tissues. A superarray analysis revealed downregulation of the chemokines monocyte chemoattractant protein (MCP)-1, Chemokine (C-X-C motif) ligand (CXCL)-10, CXCL-11, and chemokine (C-X3-C motif) ligand (CX3CL)-1; the proinflammatory cytokines IL-13 and tumor necrosis factor (TNF)-α; the TLR-4 and -5 and triggering receptor expressed on myeloid cells (TREM)-2 and upregulation of the anti-inflammatory cytokine IL-10, as well as Toll interacting protein (TOLLIP) and TREM-1 in vitamin D-treated UtSM cells. In the presence of LPS, vitamin D caused dose-dependent decreases in the messenger RNA expression of MCP-1, IL-1β, IL-13, TNF-α, TLR-4, and TLR-5, the contractile-associated proteins connexin 43, the oxytocin receptor, and the prostaglandin receptor but caused increases in IL-10 and TLR-10 in UtSM cells. The TLR-10 expression was higher in human myometrial tissue obtained from women at term not in labor compared to labor. Vitamin D also attenuated IL-1β-induced MCP-1, IL-6, connexin 43, cyclooxygenase (COX)-2, and prostaglandin receptor expression. Western analysis showed that vitamin D decreased MCP-1, TLR-4, and connexin 43 in the presence of LPS and decreased connexin 43 in the presence of IL-1β. Our results suggest that vitamin D can potentially decrease infection-induced increases in cytokines and contractile-associated proteins in the myometrium.

Zinc supplementation during pregnancy protects against lipopolysaccharide-induced fetal growth restriction and demise through its anti-inflammatory effect

LPS is associated with adverse developmental outcomes, including preterm delivery, fetal death, teratogenicity, and intrauterine growth restriction (IUGR). Previous reports showed that zinc protected against LPS-induced teratogenicity. In the current study, we investigated the effects of zinc supplementation during pregnancy on LPS-induced preterm delivery, fetal death and IUGR. All pregnant mice except controls were i.p. injected with LPS (75 μg/kg) daily from gestational day (GD) 15 to GD17. Some pregnant mice were administered zinc sulfate through drinking water (75 mg elemental Zn per liter) throughout the pregnancy. As expected, an i.p. injection with LPS daily from GD15 to GD17 resulted in 36.4% (4/11) of dams delivered before GD18. In dams that completed the pregnancy, 63.2% of fetuses were dead. Moreover, LPS significantly reduced fetal weight and crown-rump length. Of interest, zinc supplementation during pregnancy protected mice from LPS-induced preterm delivery and fetal death. In addition, zinc supplementation significantly alleviated LPS-induced IUGR and skeletal development retardation. Further experiments showed that zinc supplementation significantly attenuated LPS-induced expression of placental inflammatory cytokines and cyclooxygenase-2. Zinc supplementation also significantly attenuated LPS-induced activation of NF-κB and MAPK signaling in mononuclear sinusoidal trophoblast giant cells of the labyrinth zone. It inhibited LPS-induced placental AKT phosphorylation as well. In conclusion, zinc supplementation during pregnancy protects against LPS-induced fetal growth restriction and demise through its anti-inflammatory effect.

Protective effect of N-acetylcysteine on liver damage during chronic intrauterine hypoxia in fetal guinea pig

Chronic exposure to hypoxia during pregnancy generates a stressed intrauterine environment that may lead to fetal organ damage. The objectives of the study are (1) to quantify the effect of chronic hypoxia in the generation of oxidative stress in fetal guinea pig liver and (2) to test the protective effect of antioxidant treatment in hypoxic fetal liver injury. Pregnant guinea pigs were exposed to either normoxia (NMX) or 10.5% O(2) (HPX, 14 days) prior to term (65 days) and orally administered N-acetylcysteine ([NAC] 10 days). Near-term anesthetized fetuses were excised and livers examined by histology and assayed for malondialdehyde (MDA) and DNA fragmentation. Chronic HPX increased erythroid precursors, MDA (NMX vs HPX; 1.26 ± 0.07 vs 1.78 ± 0.07 nmol/mg protein; P < .001, mean ± standard error of the mean [SEM]) and DNA fragmentation levels in fetal livers (0.069 ± 0.01 vs 0.11 ± 0.005 OD/mg protein; P < .01). N-acetylcysteine inhibited erythroid aggregation and reduced (P < .05) both MDA and DNA fragmentation of fetal HPX livers. Thus, chronic intrauterine hypoxia generates cell and nuclear damage in the fetal guinea pig liver. Maternal NAC inhibited the adverse effects of fetal liver damage suggestive of oxidative stress. The suppressive effect of maternal NAC may implicate the protective role of antioxidants in the prevention of liver injury in the hypoxic fetus.

The role of inflammation and infection in preterm birth

Much emphasis in recent decades has been devoted to inflammation and infection as a premier causal mechanism of preterm birth. This article explores the epidemiologic, clinical, and animal data that exist to support this conceptual paradigm as well as proposed mechanisms through which to potentially mitigate the adversity of prematurity. Truly successful interventions are not likely to occur until the pathogenesis of preterm birth and the role of inflammation in causing not only parturition but also fetal and neonatal injury is fully elucidated.

N-acetyl-cysteine (NAC) attenuates LPS-induced maternal and amniotic fluid oxidative stress and inflammatory responses in the preterm gestation

OBJECTIVE

Maternal infection is associated with oxidative stress and inflammation. We sought to determine whether N-acetyl-cysteine can decrease maternal oxidative stress and the inflammatory response in preterm gestation.

STUDY DESIGN

Pregnant rats 16 days, were treated with (1) lipopolysaccharide, (2) N-acetyl-cysteine 120 minutes after lipopolysaccharide, or (3) saline solution (intraperitoneal). Six hours after lipopolysaccharide administration, serum lipid peroxide formation (LPO), tumor necrosis factor-α, interleukin-6, and interleukin-1β levels in maternal serum and amniotic fluid were determined.

RESULTS

Lipopolysaccharide significantly increased maternal serum lipid peroxide formation (24-118.5 nmol/mL; P < .05), and maternal serum and amniotic fluid tumor necrosis factor-α, interleukin-6, and interleukin-1β. N-acetyl-cysteine treatment after lipopolysaccharide significantly attenuated lipid peroxide formation (47.5 nmol/mL) and proinflammatory cytokines response in maternal serum and amniotic fluid.

CONCLUSION

Maternal and amniotic fluid oxidative stress and inflammatory stimulation are attenuated by N-acetyl-cysteine even when administered after lipopolysaccharide. These results suggest that N-acetyl-cysteine may protect the fetus from adverse sequelae associated with inflammatory stimulation.

Chronic fetal hypoxia produces selective brain injury associated with altered nitric oxide synthases

OBJECTIVE

The purpose of this study was to investigate the impact of chronic hypoxia on the nitric oxide synthase isoenzymes in specific brain structures.

STUDY DESIGN

Time-mated pregnant guinea pigs were exposed to 10.5% molecular oxygen for 14 days (animals with chronic fetal hypoxia; HPX) or room air (control animals; NMX); L-N6-(1-iminoethyl)-lysine (L-NIL; an inducible nitric oxide synthase inhibitor, 1 mg/kg/d) was administered to HPX group for 14 days (L-NIL + HPX). Fetal brains were harvested at term. Multilabeled immunofluorescence was used to generate a brain injury map. Laser capture microdissection and quantitative polymerase chain reaction were applied; cell injury markers, apoptosis activation, neuron loss, total nitric oxide, and the levels of individual nitric oxide synthase isoenzymes were quantified.

RESULTS

Chronic hypoxia causes selective fetal brain injury rather than global. Injury is associated with differentially affected nitric oxide synthases in both neurons and glial cells, with inducible macrophage-type nitric oxide synthase up-regulated at all injury sites. L-NIL attenuated the injury, despite continued hypoxia.

CONCLUSION

These studies demonstrate that chronic hypoxia selectively injures the fetal brain in part by the differential regulation of nitric oxide synthase isoenzymes in an anatomic- and cell-specific manner.

Activation of the receptor for advanced glycation end products system in women with severe preeclampsia

CONTEXT

Activation of the receptor for advanced glycation end products (RAGE) mediates cellular injury. Soluble forms of RAGE [soluble RAGE (sRAGE), endogenous secretory (esRAGE)] bind RAGE ligands, thereby preventing downstream signaling and damage.

OBJECTIVES

The objective of the study was to characterize the changes in maternal serum, amniotic fluid, and cord blood soluble receptor for advanced glycation end products (sRAGE) during physiological gestation and to provide insight into mechanisms responsible for RAGE activation in preeclampsia.

DESIGN AND SETTINGS

This was a cross-sectional study at a tertiary university hospital.

PATIENTS

We studied 135 women in the following groups: nonpregnant controls (n = 16), healthy pregnant controls (n = 68), pregnant women with chronic hypertension (n = 13), or pregnant women with severe preeclampsia (sPE; n = 38).

INTERVENTIONS AND MAIN OUTCOME MEASURES

sRAGE and esRAGE levels were evaluated in vivo by ELISA in maternal serum, amniotic fluid, and cord blood and in vitro after stimulation of the amniochorion and placental explants with lipopolysaccharide or xanthine/xanthine oxidase. Placenta and amniochorion were immunostained for RAGE. Real-time quantitative PCR measured RAGE mRNA.

RESULTS

Pregnant women had significantly decreased serum sRAGE compared with nonpregnant subjects (P < 0.001). sPE women had higher serum and amniotic fluid sRAGE and esRAGE relative to those expected for gestational age (P < 0.001). Cord blood sRAGE remained unaffected by sPE. RAGE immunoreactivity and mRNA expression appeared elevated in the amniochorion of sPE women. Xanthine/xanthine oxidase (but not lipopolysaccharide) significantly up-regulated the release of sRAGE (P < 0.001) in the amniochorion explant system.

CONCLUSIONS

Fetal membranes are a rich source of sRAGE. Elevated maternal serum and amniotic fluid sRAGE and esRAGE, paralleled by increased RAGE expression in the amniochorion, suggest activation of this system in sPE.

Pharmacological inhibition of inflammatory pathways for the prevention of preterm birth

The major cause of spontaneous preterm birth (sPTB) at less than 32 weeks of gestation is intrauterine inflammation as a consequence of colonisation of the gestational membranes by pathogenic microorganisms which trigger activation of the local innate immune system. This results in release of inflammatory mediators, leukocytosis (chorioamnionitis), apoptosis, membrane rupture, cervical ripening and onset of uterine contractions. Recent PCR evidence suggests that in the majority of cases of inflammation-driven preterm birth, microorganisms are present in the amniotic fluid, but these are not always cultured by standard techniques. The nature of the organism and its cell wall constituents, residence time in utero, microbial load, route of infection and extent of tissue penetration are all factors which can modulate the timing and magnitude of the inflammatory response and likelihood of progression to sPTB. Administration of anti-inflammatory drugs could be a viable therapeutic option to prevent sPTB and improve fetal outcomes in women at risk of intrauterine inflammation. Preventing fetal inflammation via administration of placenta-permeable drugs could also have significant perinatal benefits in addition to those related to extension of gestational age, as a fetal inflammatory response is associated with a range of significant morbidities. A number of potential drugs are available, effective against different aspects of the inflammatory process, although the pathways actually activated in spontaneous preterm labour have yet to be confirmed. Several pharmacological candidates are discussed, together with clinical and toxicological considerations associated with administration of anti-inflammatory agents in pregnancy.

N-acetylcysteine attenuates the maternal and fetal proinflammatory response to intrauterine LPS injection in an animal model for preterm birth and brain injury

OBJECTIVE

Maternal immune activation (MIA) is associated with preterm birth (PTB) and abnormal neurologic outcome. We hypothesized that N-acetylcysteine (NAC) would decrease PTB and neonatal brain injury acting as an anti-inflammatory.

METHODS

Pregnant CD-1 mice received intrauterine LPS or saline on day 15/20. They received NAC or saline and were monitored until delivery. Pups were followed and sacrificed on postnatal days 1/30 and brains were collected. Immunostaining for heavy-chain neurofilament protein (NF-H), myelin basic protein (MBP), and proteolipid protein (PLP) was performed. In another group, animals were sacrificed 6 h after treatment, and fetal brain, placenta, and myometrium were collected. Il-6, Il-1β, Il-10, and tumor necrosis factor (TNF)-α mRNA expression was determined. Nonparametric analysis was used for analysis, and pairwise comparisons were performed when appropriate.

RESULTS

Lipopolysaccharide (LPS) caused PTB (79 vs. 0%, p < 0.005), and this was reduced by NAC [0.45 (95% CI: 0.26-0.83), p < 0.008]. LPS increased IL-6 expression in myometrium and placenta. This was attenuated by NAC in myometrium. IL-1β, IL-6, and TNF-α expression increased in the fetal brain with LPS. LPS produced altered NF-H, MBP, and PLP staining, and these effects were attenuated by NAC.

CONCLUSION

NAC attenuates inflammation in this MIA model and reduces PTB and white matter injury. It is an interesting candidate for study for prevention of PTB and neurologic injury.

Effects of 4-hydroxy-2-nonenal, a major lipid peroxidation-derived aldehyde, and N-acetylcysteine on the cyclooxygenase-2 expression in human uterine myometrium

BACKGROUND

Chorioamnionitis is one of the important causes of preterm labor. Preterm labor with chorioamnionitis is associated with oxidative stress. We reported that 4-hydroxy-2-nonenal (4-HNE), a major end product of oxidative fatty acid metabolism, is accumulated in the placenta with chorioamnionitis. The aim of this study was to confirm the effect of 4-HNE on cyclooxygenase-2 (COX-2) and prostaglandin (PG) induction in the uterine myometrial tissues. We also examined the effect of N-acetylcysteine (NAC) on 4-HNE-induced COX-2 expression.

METHODS

Uterine myometrial tissues were obtained from 5 patients. One of them underwent elective cesarean section without labor, and 4 of them underwent hysterectomy because of placental previa or atonic bleeding. We stimulated the uterine myometrial tissues with 4-HNE. In addition, the tissues were pretreated with NAC before 4-HNE treatment. The expression of COX-2 mRNA was observed by real-time PCR. PGE2 and prostacyclin release into the supernatants of the tissue cultures was measured by ELISA.

RESULTS

4-HNE induced the COX-2 mRNA expression and PGE2 production in the uterine myometrial tissue culture in a dose-dependent and time-dependent manner. NAC inhibited 4-HNE-induced COX-2 expression.

CONCLUSION

4-HNE may play an important role in preterm labor. NAC might be protective against preterm labor under oxidative stress.

Tissue-specific induction of COX-2 and prostaglandins in lipopolysaccharide-stimulated extraplacental human gestational membranes in a 2-chamber transwell culture system

The current study investigates tissue-specific prostaglandin secretion and cyclooxygenase 2 (COX-2) induction in full-thickness human gestational membranes. Gestational membranes were collected from healthy, nonlaboring cesarean deliveries at 37 to 39 weeks gestation and cultured in 2-chamber Transwell devices. Lipopolysaccharide exposure (100 ng/mL for 8 hours) elevated prostaglandin E(2) and F(2α) concentrations in the amniotic chamber medium regardless of whether exposure was to the amniotic, decidual, or both sides of the membranes. However, prostaglandin E(2) and F(2 α) concentrations in the decidual chamber medium were elevated compared with controls only if the decidual side was exposed directly to lipopolysaccharide. Whereas prostaglandin F(2α) concentrations increased to similar extents in the amniotic and decidual chambers regardless of lipopolysaccharide exposure modality, prostaglandin E(2) concentrations were 22-fold higher on the amniotic side than the decidual side after lipopolysaccharide stimulation of the amnion. These findings demonstrate the propagation of prostaglandins, prostaglandin precursors, or other factors in the direction of the decidua to the amnion, but the reverse situation was not evident. Immunostaining for COX-2 was related to the side of lipopolysaccharide exposure, that is, exposure to the amnion caused immunostaining in cells of the collagen layers of the amnion and chorion, whereas exposure to the decidual side caused staining in decidual cells. These findings suggest that the inflammatory effect of lipopolysaccharide on COX-2 induction occurs within a localized area of exposure and that prostaglandins or their precursors move across the tissues of the gestational membranes by currently undefined transport mechanisms.

Inhibition of choriodecidual cytokine production and inflammatory gene expression by selective I-kappaB kinase (IKK) inhibitors

BACKGROUND AND PURPOSE

Inflammation of the extraplacental membranes plays a key role in the pathogenesis of preterm labour. The aim of this study was to screen a number of commercially available small molecule nuclear factor-kappa B inhibitors to identify candidates suitable for clinical evaluation as anti-inflammatory agents for the prevention of preterm birth.

EXPERIMENTAL APPROACH

Nine inhibitors were evaluated across a range of concentrations for their ability to inhibit lipopolysaccharide (LPS)-stimulated cytokine production in primary term choriodecidual cells in culture without affecting cell viability. Expression of 112 inflammation- and apoptosis-related genes was evaluated using boutique oligonucleotide arrays.

KEY RESULTS

Two IKKbeta inhibitors were found to be highly effective and non-toxic inhibitors of choriodecidual cytokine production: parthenolide and [5-(p-fluorophenyl)-2-ureido] thiophene-3-carboxamide (TPCA-1). Both compounds also inhibited LPS-stimulated nuclear translocation of p65/RelA. Expression of 38 genes on the arrays (34%) was significantly (P < 0.05) inhibited by TPCA-1 or parthenolide. Of the 14 genes significantly stimulated by LPS, all were inhibited by TPCA-1 and 12 were inhibited by parthenolide. Overall, gene expression was more robustly inhibited by TPCA-1 than parthenolide; however, expression of two genes was only inhibited by parthenolide. Neither compound significantly altered the expression profile of anti-apoptosis genes on the arrays.

CONCLUSIONS AND IMPLICATIONS

These studies provide evidence that pharmacological inhibition of IKKbeta activity holds promise as a potential strategy for the prevention and/or treatment of inflammation-driven preterm birth. TPCA-1 appeared the most promising compound among those tested in this study. Different inhibitors may have subtly different effect profiles despite having similar modes of action.

Intrauterine inflammation and preterm delivery

Spontaneous preterm delivery, prematurity, and low birth weight due to prematurity account for a great part of neonatal morbidity and mortality. Specifically, chronic amniotic fluid inflammation may cause preterm labor, with the involvement of different mediators that produce diverse aspects of the inflammatory response. Although bacteria are considered to be the main trigger for intrauterine infection/inflammation, viral infections also appear to be involved. Recently, molecular genetic techniques have helped us better understand the underlying pathophysiologic processes. This is especially important because epidemiological and experimental studies indicate that intrauterine infection and inflammation constitute a risk factor for adverse neurological outcome in preterm infants. Chronic subclinical chorioamnionitis associated with preterm birth can also modify lung development. Although no current clinical strategy is aimed at adapting the maternofetal inflammatory response, immunomodulators may serve as a future intervention in preterm embryos.

Is there a role for antioxidants in prevention of pulmonary hypoplasia in nitrofen-induced rat model of congenital diaphragmatic hernia?

BACKGROUND/PURPOSE

Many studies suggest a role for antioxidants in the prevention of lung hypoplasia in nitrofen-induced rat models with congenital diaphragmatic hernia (CDH). This study investigates the oxidative status and the histological outcome of prenatal administration of vitamins E and C with synergistic effect, and effect of N-acetylcysteine (NAC) to improve lung maturation of nitrofen-induced rats.

METHODS

CDH was induced by maternal administration of a single oral dose of nitrofen on day 9.5 of gestation, and the Sprague-Dawley rats were randomly divided into five groups: nitrofen (N), nitrofen + vitamin C (NC), nitrofen + vitamin E (NE), nitrofen + vitamin C + vitamin E (NCE) and nitrofen + NAC (NNAC). A control group in which only vehicle was administered was included. Cesarean section was performed on day 21. Body weight (BW) and total lung weight (LW) of all fetuses with CDH were recorded; lung histological evaluation was performed, and protein content of lungs, determination of thiobarbituric acid reactive substances, and the protein carbonyls in tissue samples were determined.

RESULTS

A total of 133 rat fetuses with CDH were investigated. The body weight and the lung weight of fetuses of all groups that were exposed to nitrofen were significantly decreased than of the control group (P < 0.05). The animals exposed to nitrofen with different antioxidants showed increased protein levels in lung tissue. However, in the NCE and the NNAC groups, protein levels were significantly increased than in the others. Malondialdehyde levels significantly decreased in the NCE and the NNAC groups when compared with the NC and the NE groups. In addition, the NCE and NNAC groups decreased protein oxidation to control levels, and no significant difference was observed between control and these two antioxidants groups. The N, NC, NE and NNAC groups showed minimal improvement in lung histology; the NCE groups showed the most improvement in lung histology when compared with the other nitrofen plus antioxidant groups.

CONCLUSION

Prenatal administration of NAC and vitamin E in combination with vitamin C represented the best effects to avoid oxidative damage and protein content of the lungs in rat pups with CDH at birth.

Maternal and fetal oxidative stress and intrapartum term fever

OBJECTIVE

The association between maternal chorioamnionitis and fetal oxidative stress has not been well established.

STUDY DESIGN

A nested case control study was performed within a prospective cohort of term nulliparous women: 20 cases (intrapartum fever of >100.4 degrees F) and 20 afebrile controls. Oxidative stress was assessed using ThioGlo-1 (TG-1; Calbiochem, San Diego, CA) fluorescent sulfhydryl detection. Median levels (+/- interquartile range) of protein-thiol sulfhydryls were compared.

RESULTS

In early labor, maternal oxidative stress (lower protein sulfhydryls) was significantly higher in those women who subsequently had intrapartum fever develop (79.87 +/- 22.88 vs 127.73 +/- 43.79 counts/second per microg protein; P < .001). In contrast, cord serum sulfhydryls were not different between groups (75.77 +/- 14.00 vs 75.04 +/- 17.83 counts/second per microg protein; P = .99)

CONCLUSION

Our data suggest that the term human fetus is protected from maternal oxidative stress associated with intrapartum fever. However, maternal oxidative status in early labor is associated with subsequent intrapartum fever. Optimal fetal neuroprotection will require a more precise knowledge of pathogenic mechanisms.

Deficits in lung alveolarization and function after systemic maternal inflammation and neonatal hyperoxia exposure

Systemic maternal inflammation contributes to preterm birth and is associated with development of bronchopulmonary dysplasia (BPD). Infants with BPD exhibit decreased alveolarization, diffuse interstitial fibrosis with thickened alveolar septa, and impaired pulmonary function. We tested the hypothesis that systemic prenatal LPS administration to pregnant mice followed by postnatal hyperoxia exposure is associated with prolonged alterations in pulmonary structure and function after return to room air (RA) that are more severe than hyperoxia exposure alone. Timed-pregnant C3H/HeN mice were dosed with LPS (80 microg/kg) or saline on gestation day 16. Newborn pups were exposed to RA or 85% O2 for 14 days and then to RA for an additional 14 days. Data were collected and analyzed on postnatal days 14 and 28. The combination of prenatal LPS and postnatal hyperoxia exposure generated a phenotype with more inflammation (measured as no. of macrophages per high-power field) than either insult alone at day 28. The combined exposures were associated with a diffuse fibrotic response [measured as hydroxyproline content (microg)] but did not induce a more severe developmental arrest than hyperoxia alone. Pulmonary function tests indicated that hyperoxia, independent of maternal exposure, induced compliance decreases on day 14 that did not persist after RA recovery. Either treatment alone or combined induced an increase in resistance on day 14, but the increase persisted on day 28 only in pups receiving the combined treatment. In conclusion, the combination of systemic maternal inflammation and neonatal hyperoxia induced a prolonged phenotype of arrested alveolarization, diffuse fibrosis, and impaired lung mechanics that mimics human BPD. This new model should be useful in designing studies of specific mechanisms and interventions that could ultimately be utilized to define therapies to prevent BPD in premature infants.

Effect of N-acetyl-cysteine after ovarian drilling in clomiphene citrate-resistant PCOS women: a pilot study

The aim of this randomized double-blind placebo-controlled pilot study was to evaluate N-acetyl-cysteine (NAC) as an adjunctive therapy following unilateral laparoscopic ovarian drilling (LOD) for clomiphene citrate-resistant women with polycystic ovary syndrome (PCOS). A total of 60 patients with clomiphene citrate-resistant PCOS who underwent unilateral LOD were assigned randomly to receive either NAC 1.2 g/d (group A=30) or placebo (group B=30) for 5 days starting at day 3 of the cycle for 12 consecutive cycles. The primary outcome was pregnancy rate; secondary outcomes were ovulation rates, endometrial thickness and pregnancy outcome. Baseline clinical, endocrine, and sonographic characteristics were similar in the two groups. A significant increase in both ovulation and pregnancy rates was observed in the NAC group, compared with placebo [87% versus 67% (RR 1.3; 95% CI 1.2-2.7) and 77% versus 57% (RR 1.4; 95% CI 1.1-2.7), respectively, P<0.01]. Moreover, miscarriage rates were significantly lower and live birth rates were significantly higher in the NAC group [8.7% versus 23.5% (RR 0.4; 95% CI 0.1-3.7) and 67% versus 40% (RR 1.7; 95% CI 0.3-3.5), respectively, P<0.01]. In conclusion, NAC is a novel adjuvant therapy after unilateral LOD which might help improve overall reproductive outcome.

Age- and gender-dependent impairments of neurobehaviors in mice whose mothers were exposed to lipopolysaccharide during pregnancy

Lipopolysaccharide (LPS)-induced intrauterine infection has been associated with neurodevelopmental injury in rodents. The purpose of the present study was to analyze the dynamic changes of neurobehaviors in mice whose mothers were exposed to LPS during pregnancy. The pregnant mice were intraperitoneally (i.p.) injected with LPS (8 microg/kg) daily from gestational day (gd) 8 to gd 15. A battery of neurobehavioral tasks was performed in mice at postnatal day (PND) 70, 200, 400 and 600. Results showed that the spatial learning and memory ability, determined by radial six-arm water maze (RAWM), were obviously impaired in two hundred-day-old female mice and four hundred-day-old male mice whose mothers were exposed to LPS during pregnancy. Open field test showed that the number of squares crossed and peripheral time, a marker of anxiety and exploration activity, were markedly increased in two hundred-day-old female mice following prenatal LPS exposure. In addition, prenatal LPS exposure significantly shortened the latency to the first grid crossing in six hundred-day-old female offspring. Moreover, sensorimotor impairment in the beam walking was observed in two hundred-day-old female mice whose mothers were exposed to LPS during pregnancy. Species-typical behavior examination showed that prenatal LPS exposure markedly increased weight burrowed in seventy-day-old male offspring and six hundred-day-old female offspring. Correspondingly, prenatal LPS exposure significantly reduced weight hoarded in two hundred-day-old female offspring. Taken together, these results suggest that prenatal LPS exposure induces neurobehavioral impairments at adulthood in an age- and gender-dependent manner.

Arsenate-induced maternal glucose intolerance and neural tube defects in a mouse model

BACKGROUND

Epidemiological studies have linked environmental arsenic (As) exposure to increased type 2 diabetes risk. Periconceptional hyperglycemia is a significant risk factor for neural tube defects (NTDs), the second most common structural birth defect. A suspected teratogen, arsenic (As) induces NTDs in laboratory animals.

OBJECTIVES

We investigated whether maternal glucose homeostasis disruption was responsible for arsenate-induced NTDs in a well-established dosing regimen used in studies of arsenic's teratogenicity in early neurodevelopment.

METHODS

We evaluated maternal intraperitoneal (IP) exposure to As 9.6 mg/kg (as sodium arsenate) in LM/Bc/Fnn mice for teratogenicity and disruption of maternal plasma glucose and insulin levels. Selected compounds (insulin pellet, sodium selenate (SS), N-acetyl cysteine (NAC), l-methionine (L-Met), N-tert-Butyl-alpha-phenylnitrone (PBN)) were investigated for their potential to mitigate arsenate's effects.

RESULTS

Arsenate caused significant glucose elevation during an IP glucose tolerance test (IPGTT). Insulin levels were not different between arsenate and control dams before (arsenate, 0.55 ng/dl; control, 0.48 ng/dl) or after glucose challenge (arsenate, 1.09 ng/dl; control, 0.81 ng/dl). HOMA-IR index was higher for arsenate (3.9) vs control (2.5) dams (p=0.0260). Arsenate caused NTDs (100%, p<0.0001). Insulin pellet and NAC were the most successful rescue agents, reducing NTD rates to 45% and 35%.

CONCLUSIONS

IPGTT, insulin assay, and HOMA-IR results suggest a modest failure of glucose stimulated insulin secretion and insulin resistance characteristic of glucose intolerance. Insulin's success in preventing arsenate-induced NTDs provides evidence that these arsenate-induced NTDs are secondary to elevated maternal glucose. The NAC rescue, which did not restore maternal glucose or insulin levels, suggests oxidative disruption plays a role.

Characterization of RAGE, HMGB1, and S100beta in inflammation-induced preterm birth and fetal tissue injury

Immune activation represents an adaptive reaction triggered by both noxious exogenous (microbes) and endogenous [high mobility group box-1 protein (HMGB1), S100 calcium binding proteins] inducers of inflammation. Cell stress or necrosis lead the release of HMGB1 and S100 proteins in the extracellular compartment where they act as damage-associated molecular pattern molecules (or alarmins) by engaging the receptor for advanced glycation end-products (RAGE). Although the biology of RAGE is dictated by the accumulation of damage-associated molecular pattern molecules at sites of tissue injury, the role of RAGE in mediating antenatal fetal injury remains unknown. First, we studied the relationships at birth between the intensity of human fetal inflammation and sRAGE (an endogenous RAGE antagonist), HMGB1, and S100beta protein. We found significantly lower sRAGE in human fetuses that mounted robust inflammatory responses. HMGB1 levels correlated significantly with levels of interleukin-6 and S100beta in fetal circulation. We then evaluated the levels and areas of tissue expression of RAGE, HMGB1, and S100beta in specific organs of mouse fetuses on E16. Using an animal model of endotoxin-induced fetal damage and preterm birth, we determined that inflammation induces a significant change in expression of RAGE and HMGB1, but not S100beta, at sites of tissue damage. Our findings indicate that RAGE and HMGB1 may be important mediators of cellular injury in fetuses delivered in the setting of inflammation-induced preterm birth.

Nitrative and oxidative stress in toxicology and disease

Persistent inflammation and the generation of reactive oxygen and nitrogen species play pivotal roles in tissue injury during disease pathogenesis and as a reaction to toxicant exposures. The associated oxidative and nitrative stress promote diverse pathologic reactions including neurodegenerative disorders, atherosclerosis, chronic inflammation, cancer, and premature labor and stillbirth. These effects occur via sustained inflammation, cellular proliferation and cytotoxicity and via induction of a proangiogenic environment. For example, exposure to the ubiquitous air pollutant ozone leads to generation of reactive oxygen and nitrogen species in lung macrophages that play a key role in subsequent tissue damage. Similarly, studies indicate that genes involved in regulating oxidative stress are altered by anesthetic treatment resulting in brain injury, most notable during development. In addition to a role in tissue injury in the brain, inflammation, and oxidative stress are implicated in Parkinson's disease, a neurodegenerative disease characterized by the loss of dopamine neurons. Recent data suggest a mechanistic link between oxidative stress and elevated levels of 3,4-dihydroxyphenylacetaldehyde, a neurotoxin endogenous to dopamine neurons. These findings have significant implications for development of therapeutics and identification of novel biomarkers for Parkinson's disease pathogenesis. Oxidative and nitrative stress is also thought to play a role in creating the proinflammatory microenvironment associated with the aggressive phenotype of inflammatory breast cancer. An understanding of fundamental concepts of oxidative and nitrative stress can underpin a rational plan of treatment for diseases and toxicities associated with excessive production of reactive oxygen and nitrogen species.

Prophylactic maternal n-acetylcysteine before lipopolysaccharide suppresses fetal inflammatory cytokine responses

OBJECTIVE

Maternal infection or inflammation may induce fetal inflammatory responses and potentially fetal brain injury. We sought to determine whether prophylactic n-acetylcysteine (NAC), a known antiinflammatory, may modulate the fetal cytokine response to maternal lipopolysaccharide (LPS).

STUDY DESIGN

Pregnant Sprague Dawley rats (20/21 days = 0.95 gestation; n = 35) received intraperitoneal NAC (300 mg/kg) or saline at time 0 and LPS (500 microg/kg) or saline at 30 minutes. An additional group received NAC following saline. At 6 hours, rats were killed and interleukin (IL)-6, IL-1 beta, and IL-10 levels were determined in fetal and maternal blood.

RESULTS

Following maternal LPS, fetal blood IL-6 (median [25th, 75th] 50 [27, 50] to 2072 [448, 4853] pg/mL) and IL-1 beta (74 [10, 139] to 391 [284, 797] pg/mL) significantly increased. NAC before LPS significantly reduced the fetal IL-6 and IL-1 beta response. Fetal IL-10 was not attenuated by any treatment. NAC attenuated both maternal pro- and antiinflammatory responses to LPS.

CONCLUSION

Maternal NAC suppressed fetal and maternal inflammatory responses to maternal LPS. These results suggest that prophylactic NAC may protect the fetus from maternal inflammation.

Soluble tumor necrosis factor receptor mediates cell proliferation on lipopolysaccharide-stimulated cultured human decidual stromal cells

The tumor necrosis factor-alpha (TNF-α) cytokine receptor system modulates apoptosis in many cell types, so we have investigated the role of sTNFR1 in bacterial lipopolysaccharide (LPS)-induced cell death in cultured human decidual stromal cells, hypothesizing that sTNFR1 might play a central role in this action. In this work we characterized in vitro decidual stromal cell viability with LPS treatment and LPS and sTNFR1 co-treatment. We found that LPS treatment induced decidual stromal cell death in a dose-dependent manner and that sTNFR1 blocked the effect of the LPS treatment. There was a significant proliferation among cells co-incubated with LPS at 10 μg/mL and sTNFR1 at 0.1 μg/mL compared with LPS and sTNFR1 at 0.01, 0.05, 0.2 and 0.5 μg/mL (p < 0.01). This study demonstrated that LPS led to decidual stromal cell death in vitro but sTNFR1 down-regulates the cell death due to LPS under the same conditions. Taken together, these results suggested that sTNFR1 could participate in a protective mechanism against endotoxin.

Chronic hypoxemia absent bacterial infection is one cause of the fetal inflammatory response syndrome (FIRS)

The object of the investigation was to determine whether chronic fetal hypoxemia triggers a systemic fetal inflammatory response absent bacterial infection. Chronically hypoxemic (10.5% O(2)) and lipopolysaccharide (LPS; 400 microg/kg of maternal body weight) injected intrauterine (but extra-amniotic) treated pregnant guinea pigs were used with appropriate controls. The presence of bacteria in the amniotic cavity was sought using polymerase chain reaction (PCR). Interleukin 6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) protein levels were measured in fetal sera and amniotic fluid (AF) by a commercially available, sensitive enzyme-linked immunosorbent assay (ELISA; IL-6 and TNF-alpha messenger RNA (mRNA) were also quantified in multiple fetal organs using real-time PCR. Prokaryotic DNA was not amplified from any sample, confirming the animals were not infected. Chronic hypoxemia dramatically increased IL-6 and TNF-alpha proteins in fetal sera and mRNA in lung, heart, and brain. There were no significant changes in either cytokine observed in the AF, fetal membranes, or fetal liver. Intrauterine but extra amniotic LPS also increased IL-6 and TNF-alpha protein in fetal sera and mRNA in lung, heart, and brain, plus increased the levels of both cytokines (protein/mRNA) in AF, fetal membranes, and fetal liver. Thus, an elevation in fetal blood IL-6 is not a specific marker of infection-induced fetal inflammatory response syndrome (FIRS). And in contrast to the fetal blood, an elevation in AF IL-6 seems associated only with LPS-induced FIRS.

Fetal renal artery impedance as assessed by Doppler ultrasound in pregnancies complicated by intraamniotic inflammation and preterm birth

OBJECTIVE

The objective of the study was to evaluate the fetal renal artery impedance in the context of inflammation-associated preterm birth.

STUDY DESIGN

We conducted a prospective Doppler assessment of the fetal renal artery impedance in 70 singleton fetuses. The study group consisted of 56 premature fetuses (median, 28.1 [interquartile range, 25.3-30.6] weeks at enrollment). Gestational age (GA) reference ranges were generated based on fetuses with uncomplicated pregnancies (n = 14). Doppler studies included renal artery pulsatility index (PI), resistance index (RI), systolic/diastolic (S/D) ratio, and presence or absence of end-diastolic blood flow. Proteomic profiling (surface-enhanced laser desorption ionization time-of-flight) was used for assessment of intraamniotic inflammation and biomarker peak corresponding to beta2-microglubin. Data were interpreted in relationship to amniotic fluid index (AFI), cord blood interleukin (IL)-6 and erythropoietin (EPO) levels. The cardiovascular and metabolic profiles of the neonates were investigated in the first 24 hours of life.

RESULTS

Fetuses delivered by mothers with intraamniotic inflammation had higher cord blood IL-6 but not EPO levels. Fetal inflammation did not affect either renal artery PI, RI, S/D ratio, or end-diastolic blood flow. Neonates delivered in the context of intraamniotic inflammation had higher serum blood urea nitrogen levels, which correlated significantly with AF IL-6 levels. The renal artery RI and SD ratio were inversely correlated with the AFI independent of GA, cord blood IL-6, and status of the membranes.

CONCLUSION

The fetus is capable of sustaining normal renal artery impedance despite inflammation. Resistance in the renal vascular bed affects urine output independent of inflammation.

Dendrimer-drug conjugates for tailored intracellular drug release based on glutathione levels

N-Acetyl-L-cysteine (NAC) is an antioxidant and anti-inflammatory agent with significant potential in clinical applications including stroke and neuroinflammation. The drug shows high plasma binding upon IV administration, requiring high doses and associated side effects. Through the use of an appropriate delivery vehicle, the stability and efficacy of NAC can be significantly improved. Dendrimers are an emerging class of nanoscale drug delivery vehicles, which enable high drug payloads and intracellular delivery. Poly(amidoamine) (PAMAM) dendrimer-NAC conjugates having cleavable disulfide linkages are designed for intracellular delivery based on glutathione levels. We have successfully synthesized two conjugates with a cationic G4-NH(2) and an anionic G3.5-COOH PAMAM dendrimer with NAC payloads of 16 and 18 per dendrimer, respectively, as confirmed by (1)H NMR and MALDI-TOF analysis. NAC release from the conjugates at intracellular and extracellular glutathione (GSH) concentrations were evaluated by reverse phase HPLC (RP-HPLC) analysis, and approximately 70% of NAC payload was released within one hour at intracellular GSH concentrations (approximately 10 mM), whereas negligible NAC release was observed at extracellular GSH levels (2 microM). FITC-labeled conjugates showed that they enter cells rapidly and localize in the cytoplasm of lipopolysaccharide (LPS)-activated microglial cells (the target cells in vivo). The significantly improved efficacies of dendrimer-NAC conjugates in activated microglial cells was confirmed by measuring the nitrite inhibition in the cell culture medium, which is an indication of the antioxidative property of the drug. Both G4-NH(2) and G3.5-COOH conjugates showed significantly better nitrite inhibition both at 24 and 72 h compared to free NAC, by as much as a factor of 16. The results indicate that PAMAM dendrimer conjugates produce higher local NAC concentration inside the cells, with GSH-sensitive disulfide linker enabling efficient and rapid cellular release of the drug.

Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases

BACKGROUND

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation.

REVIEW

We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here.

CONCLUSION

Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.

N-acetyl cysteine for treatment of recurrent unexplained pregnancy loss

Pregnancy could be associated with a state of oxidative stress that could initiate and propagate a cascade of changes that may lead to pregnancy wastage. This process of oxidative stress may be suppressed by the antioxidant effect of N-acetyl cysteine (NAC). The current study aimed to evaluate the effect of NAC therapy in patients diagnosed with unexplained recurrent pregnancy loss (RPL). The study was a prospective controlled study performed in the Women's Health Centre, Assiut University, Egypt. A group of 80 patients with history of recurrent unexplained pregnancy loss were treated with NAC 0.6 g + folic acid 500 microg/day and compared with an aged-matched group of 86 patients treated with folic acid 500 microg/day alone. NAC + folic acid compared with folic acid alone caused a significantly increased rate of continuation of a living pregnancy up to and beyond 20 weeks [P < 0.002, relative risk (RR) 2.9, 95% confidence interval (CI) 1.5-5.6]. NAC + folic acid was associated with a significant increase in the take-home baby rate as compared with folic acid alone (P < 0.047, RR 1.98, 95% CI 1.3-4.0). In conclusion, NAC is a well-tolerated drug that could be a potentially effective treatment in patients with unexplained RPL.

Effect of oral N-acetyl cysteine on recurrent preterm labor following treatment for bacterial vaginosis

OBJECTIVE

To evaluate the effect of N-acetyl cysteine (NAC) on gestational age at delivery in women with previous preterm labor and bacterial vaginosis.

METHODS

A randomized, double-blind, placebo-controlled trial with 280 women between 16 and 18 weeks of pregnancy who had 1 previous preterm birth and had just been successfully treated for bacterial vaginosis with metronidazole for 1 week. The women were randomized to receive 0.6 g of NAC per day plus 17-hydroxyprogesterone caproate (17-OHPC) or placebo plus 17-OHPC until 36 completed weeks of pregnancy or active labor. A vaginal swab was taken during labor.

RESULTS

Reaching 36 weeks of pregnancy was more frequent (P<0.05) and gestational age at delivery was significantly higher in the NAC than in the placebo group (37.4 weeks+/-0.4 weeks vs 34.1 weeks+/-1.2 weeks, P<0.05). The discontinuation rate was 11.4% in the NAC group.

CONCLUSIONS

Oral NAC was found to reduce the recurrence of preterm birth in patients with bacterial vaginosis.