Antenatal pharmacokinetics and placental transfer of N-acetylcysteine in chorioamnionitis for fetal neuroprotection

Epigenetic regulation by hypoxia, N-acetylcysteine and hydrogen sulphide of the fetal vasculature in growth restricted offspring: A study in humans and chicken embryos

Fetal growth restriction (FGR) is a common outcome in human suboptimal gestation and is related to prenatal origins of cardiovascular dysfunction in offspring. Despite this, therapy of human translational potential has not been identified. Using human umbilical and placental vessels and the chicken embryo model, we combined cellular, molecular, and functional studies to determine whether N-acetylcysteine (NAC) and hydrogen sulphide (H2S) protect cardiovascular function in growth-restricted unborn offspring. In human umbilical and placental arteries from control or FGR pregnancy and in vessels from near-term chicken embryos incubated under normoxic or hypoxic conditions, we determined the expression of the H2S gene CTH (i.e. cystathionine γ-lyase) (via quantitative PCR), the production of H2S (enzymatic activity), the DNA methylation profile (pyrosequencing) and vasodilator reactivity (wire myography) in the presence and absence of NAC treatment. The data show that FGR and hypoxia increased CTH expression in the embryonic/fetal vasculature in both species. NAC treatment increased aortic CTH expression and H2S production and enhanced third-order femoral artery dilator responses to the H2S donor sodium hydrosulphide in chicken embryos. NAC treatment also restored impaired endothelial relaxation in human third-to-fourth order chorionic arteries from FGR pregnancies and in third-order femoral arteries from hypoxic chicken embryos. This NAC-induced protection against endothelial dysfunction in hypoxic chicken embryos was mediated via nitric oxide independent mechanisms. Both developmental hypoxia and NAC promoted vascular changes in CTH DNA and NOS3 methylation patterns in chicken embryos. Combined, therefore, the data support that the effects of NAC and H2S offer a powerful mechanism of human translational potential against fetal cardiovascular dysfunction in complicated pregnancy. KEY POINTS: Gestation complicated by chronic fetal hypoxia and fetal growth restriction (FGR) increases a prenatal origin of cardiovascular disease in offspring, increasing interest in antenatal therapy to prevent against a fetal origin of cardiovascular dysfunction. We investigated the effects between N-acetylcysteine (NAC) and hydrogen sulphide (H2S) in the vasculature in FGR human pregnancy and in chronically hypoxic chicken embryos. Combining cellular, molecular, epigenetic and functional studies, we show that the vascular expression and synthesis of H2S is enhanced in hypoxic and FGR unborn offspring in both species and this acts to protect their vasculature. Therefore, the NAC/H2S pathway offers a powerful therapeutic mechanism of human translational potential against fetal cardiovascular dysfunction in complicated pregnancy.

The influence of chorioamnionitis on respiratory drive and spontaneous breathing of premature infants at birth: a narrative review

Most very premature infants breathe at birth but require respiratory support in order to stimulate and support their breathing. A significant proportion of premature infants are affected by chorioamnionitis, defined as an umbrella term for antenatal inflammation of the foetal membranes and umbilical vessels. Chorioamnionitis produces inflammatory mediators that potentially depress the respiratory drive generated in the brainstem. Such respiratory depression could maintain itself by delaying lung aeration, hampering respiratory support at birth and putting infants at risk of hypoxic injury. This inflammatory-mediated respiratory depression may contribute to an association between chorioamnionitis and increased requirement of neonatal resuscitation in premature infants at birth. This narrative review summarises mechanisms on how respiratory drive and spontaneous breathing could be influenced by chorioamnionitis and provides possible interventions to stimulate spontaneous breathing.  Conclusion: Chorioamnionitis could possibly depress respiratory drive and spontaneous breathing in premature infants at birth. Interventions to stimulate spontaneous breathing could therefore be valuable. What is Known: • A large proportion of premature infants are affected by chorioamnionitis, antenatal inflammation of the foetal membranes and umbilical vessels. What is New: • Premature infants affected by chorioamnionitis might be exposed to higher concentrations of respiratory drive inhibitors which could depress breathing at birth. • Premature infants affected by chorioamnionitis seem to be associated with a higher and more extensive requirement of resuscitation at birth.

Transcutaneous auricular vagus nerve stimulation may benefit from the addition of N-acetylcysteine to facilitate motor learning in infants of diabetic mothers failing oral feeds

Objective

This study aims to determine if pretreating with enteral N-acetylcysteine (NAC) improves CNS oxidative stress and facilitates improvement in oromotor skills during transcutaneous auricular nerve stimulation (taVNS) paired with oral feedings in infants of diabetic mothers (IDMs) who are failing oral feeds.

Methods

We treated 10 IDMs who were gastrostomy tube candidates in an open-label trial of NAC and taVNS paired with oral feeding. NAC (75 or 100 mg/kg/dose) was given by nasogastric (NG) administration every 6 h for 4 days, then combined with taVNS paired with 2 daily feeds for another 14 days. NAC pharmacokinetic (PK) parameters were determined from plasma concentrations at baseline and at steady state on day 4 of treatment in conjunction with magnetic resonance spectroscopic (MRS) quantification of CNS glutathione (GSH) as a marker of oxidative stress. We compared increases in oral feeding volumes before and during taVNS treatment and with a prior cohort of 12 IDMs who largely failed to achieve full oral feeds with taVNS alone.

Results

NAC 100 mg/kg/dose every 6 h NG resulted in plasma [NAC] that increased [GSH] in the basal ganglia with a mean of 0.13 ± 0.08 mM (p = 0.01, compared to baseline). Mean daily feeding volumes increased over 14 days of NAC + taVNS compared to the 14 days before treatment and compared to the prior cohort of 12 IDMs treated with taVNS alone. Seven IDMs reached full oral feeds sufficient for discharge, while three continued to have inadequate intake.

Conclusion

In IDM failing oral feeds, NAC 100 mg/kg/dose every 6 h NG for 4 days before and during taVNS paired with oral feeding increased CNS GSH, potentially mitigating oxidative stress, and was associated with improving functional feeding outcomes compared to taVNS alone in a prior cohort. This represents a novel approach to neuromodulation and supports the concept that mitigation of ongoing oxidative stress may increase response to taVNS paired with a motor task.

N-acetylcysteine Pharmacology and Applications in Rare Diseases-Repurposing an Old Antioxidant

N-acetylcysteine (NAC), a precursor of cysteine and, thereby, glutathione (GSH), acts as an antioxidant through a variety of mechanisms, including oxidant scavenging, GSH replenishment, antioxidant signaling, etc. Owing to the variety of proposed targets, NAC has a long history of use as a prescription product and in wide-ranging applications that are off-label as an over-the-counter (OTC) product. Despite its discovery in the early 1960s and its development for various indications, systematic clinical pharmacology explorations of NAC pharmacokinetics (PK), pharmacodynamic targets, drug interactions, and dose-ranging are sorely limited. Although there are anecdotal instances of NAC benefits in a variety of diseases, a comprehensive review of the use of NAC in rare diseases does not exist. In this review, we attempt to summarize the existing literature focused on NAC explorations in rare diseases targeting mitochondrial dysfunction along with the history of NAC usage, approved indications, mechanisms of action, safety, and PK characterization. Further, we introduce the research currently underway on other structural derivatives of NAC and acknowledge the continuum of efforts through pre-clinical and clinical research to facilitate further therapeutic development of NAC or its derivatives for rare diseases.

Loss of Nicotinamide nucleotide transhydrogenase sensitizes embryos to ethanol-induced neural crest and neural apoptosis via generation of reactive oxygen species

Fetal alcohol spectrum disorders (FASD) are a continuum of birth defects caused by prenatal alcohol exposure. FASD are the most common environmentally induced birth defect and are highly variable. The genetics of an individual influence the severity of their FASD phenotype. However, the genes that sensitize an individual to ethanol-induced birth defects are largely unknown. The ethanol-sensitive mouse substrain, C57/B6J, carries several known mutations including one in Nicotinamide nucleotide transhydrogenase (Nnt). Nnt is a mitochondrial transhydrogenase thought to have an important role in detoxifying reactive oxygen species (ROS) and ROS has been implicated in ethanol teratogenesis. To directly test the role of Nnt in ethanol teratogenesis, we generated zebrafish nnt mutants via CRISPR/Cas9. Zebrafish embryos were dosed with varying concentrations of ethanol across different timepoints and assessed for craniofacial malformations. We utilized a ROS assay to determine if this could be a contributing factor of these malformations. We found that exposed and unexposed mutants had higher levels of ROS compared to their wildtype counterparts. When treated with ethanol, nnt mutants experienced elevated apoptosis in the brain and neural crest, a defect that was rescued by administration of the antioxidant, N-acetyl cysteine (NAC). NAC treatment also rescued most craniofacial malformations. Altogether this research demonstrates that ethanol-induced oxidative stress leads to craniofacial and neural defects due to apoptosis in nnt mutants. This research further supports the growing body of evidence implicating oxidative stress in ethanol teratogenesis. These findings suggest that antioxidants can be used as a potential therapeutic in the treatment of FASD.

Intestine and brain TLR-4 modulation following N-acetyl-cysteine treatment in NEC rodent model

Necrotizing enterocolitis (NEC) brain injury is mediated through Toll-like receptor 4 (TLR4) on the intestinal epithelium and brain microglia. Our aim was to determine whether postnatal and/or prenatal NAC can modify NEC associated intestinal and brain TLR4 expression and brain glutathione levels in a rat model of NEC. Newborn Sprague-Dawley rats were randomized into three groups: Control (n = 33); NEC (n = 32)-hypoxia and formula feeding; and NEC-NAC (n = 34)-received NAC (300 mg/kg IP) in addition to NEC conditions. Two additional groups included pups of dams treated once daily with NAC (300 mg/kg IV) for the last 3 days of pregnancy: NAC-NEC (n = 33) or NAC-NEC-NAC (n = 36) with additional postnatal NAC. Pups were sacrificed on the fifth day, and ileum and brains harvested for TLR-4 and glutathione protein levels. Brain and ileum TLR-4 protein levels were significantly increased in NEC offspring as compared to control (brain 2.5 ± 0.6 vs. 0.88 ± 0.12 U and ileum 0.24 ± 0.04 vs. 0.09 ± 0.01, p < 0.05). When NAC was administered only to dams (NAC-NEC) a significant decrease in TLR-4 levels was demonstrated in both offspring brain (1.53 ± 0.41 vs. 2.5 ± 0.6 U, p < 0.05) and ileum (0.12 ± 0.03 vs. 0.24 ± 0.04 U, p < 0.05) as compared to NEC. The same pattern was demonstrated when NAC was administered only or postnatally. The decrease in brain and ileum glutathione levels observed in NEC offspring was reversed with all NAC treatment groups. NAC reverses the increase in ileum and brain TLR-4 levels and the decrease in brain and ileum glutathione levels associated with NEC in a rat model, and thus may protect from NEC associated brain injury.

Dietary macrominerals: Updated review of their role and orchestration in human nutrition throughout the life cycle with sex differences

Macrominerals play vital roles in a multitude of physiologic systems. A myriad of biochemical reactions are dependent on or affected by these electrolytes. The current review attempts to identify the role of macrominerals as calcium, phosphorus, magnesium, sodium, potassium and sulfur in human health, in addition to their absorption and homeostasis inside the body. We also focused on their amount in major food sources and the recommended daily intake of each macromineral. In addition, a deep insight into the orchestration of the 6 different macrominerals' requirements is presented across the human life cycle, beginning from fertility and pregnancy, and reaching adulthood and senility, with insight on interactions among them and underlying action mechanisms. The effect of sex is also presented for each mineral at each life stage to highlight the different daily requirements and/ or effects. The current review identified the role of macrominerals in human health, in addition to their absorption and homeostasis in the body. Based on the in-depth understanding of the factors influencing the metabolism of macrominerals, we could better explore their safety and possible therapeutic potential in specific disorders. There is still a need to precisely demonstrate the bioavailability of macrominerals from various types of functional food.

CD177+ cells produce neutrophil extracellular traps that promote biliary atresia

BACKGROUND & AIMS

We have previously reported on the potential pathogenic role of neutrophils in biliary atresia (BA). Herein, we aimed to delineate the role of CD177+ neutrophils in the pathogenesis of BA.

METHODS

Immune cells from the livers of mice with rhesus rotavirus-induced BA were analysed. Single-cell RNA-sequencing was performed to specifically analyse Gr-1⁺ (Ly6C/Ly6G⁺) cells in the liver. Gene expression profiles of CD177⁺ cells were analysed using the Smart-Seq RNA-sequencing method, and the pathogenesis of BA was examined in Cd177^-/- mice. Neutrophil extracellular trap (NET) inhibitors were used to determine the role of CD177⁺ cell-derived NETs in BA-associated bile duct damage, and a pilot clinical study evaluated the potential effects of N-acetylcysteine on NET release in BA.

RESULTS

Increased levels of Gr-1⁺ cells were observed in the livers of mice with rhesus rotavirus-induced BA. RNA-sequencing analysis revealed that CD177⁺ cells were the main population of Gr-1⁺ cells and expressed elevated levels of both interferon-stimulated and neutrophil degranulation genes. Cd177^-/- BALB/c mice exhibited delayed disease onset and reduced morbidity and mortality. High numbers of mitochondria were detected in CD177⁺ cells derived from mice with BA; these cells were associated with increased levels of reactive oxygen species and increased NET formation, which induced the apoptosis of biliary epithelial cells in cocultures. In a pilot clinical study, the administration of N-acetylcysteine to patients with BA reduced CD177⁺ cell numbers and reactive oxygen species levels, indicating a potential beneficial effect.

CONCLUSIONS

Our data indicate that CD177⁺ cells play an important role in the initiation of BA pathogenesis via NET formation.

CLINICAL TRIAL REGISTRATION

The pilot study of N-acetylcysteine treatment in patients with BA was registered on the Chinese Clinical Trial Registry (ChiCTR2000040505).

LAY SUMMARY

Neutrophils (a type of innate immune cell, i.e. an immune cell that doesn't target a specific antigen) are thought to play a role in the development of biliary atresia (a rare but potentially lethal condition of the bile ducts that occurs in infants). Herein, we found that neutrophils expressing a particular protein (CD177) played an important role in bile duct damage by releasing a special structure (NET) that can trap and kill pathogens but that can also cause severe tissue damage. A pilot study in patients with biliary atresia showed that inhibiting NETs could have a beneficial effect.

Effects of NAC and Gallic Acid on the Proliferation Inhibition and Induced Death of Lung Cancer Cells with Different Antioxidant Capacities

N-acetylcysteine (NAC) is a recognized antioxidant in culture studies and treatments for oxidative stress-related diseases, but in some cases, NAC is a pro-oxidant. To study the effect of NAC on cell proliferation in the presence or absence of ROS stress, we used the stable ROS generator gallic acid (GA) to treat CL1-0 lung cancer cell models with different antioxidant activities. Different antioxidant activities were achieved through the ectopic expression of different PERP-428 single nucleotide polymorphisms. GA increased ROS levels in CL1-0/PERP-428C cells and caused cell death but had no effect on CL1-0/PERP-428G cells within 24 h. We found that 0.1 mM NAC eliminated GA-induced growth inhibition, but 0.5 mM NAC enhanced GA-induced CL1-0/PERP-428C cell death. However, in the absence of GA, NAC exceeding 2 mM inhibited the growth of CL1-0/PERP-428G cells more significantly than that of CL1-0/PERP-428C cells. Without GA, NAC has an antioxidant effect. Under GA-induced ROS stress, NAC may have pro-oxidant effects. Each cell type has a unique range of ROS levels for survival. The levels of ROS in the cell determines the sensitivity of the cell to an antioxidant or pro-oxidant. Cells with different antioxidant capacities were used to show that the intracellular ROS level affects NAC function and provides valuable information for the adjuvant clinical application of NAC.

NAC and Vitamin D Improve CNS and Plasma Oxidative Stress in Neonatal HIE and Are Associated with Favorable Long-Term Outcomes

N-acetylcysteine (NAC) and vitamin D provide effective neuroprotection in animal models of severe or inflammation-sensitized hypoxic ischemic encephalopathy (HIE). To translate these FDA-approved drugs to HIE neonates, we conducted an early phase, open-label trial of 10 days of NAC (25, 40 mg/kg q12h) + 1,25(OH)2D (calcitriol 0.05 mg/kg q12h, 0.03 mg/kg q24h), (NVD), for pharmacokinetic (PK) estimates during therapeutic hypothermia and normothermia. We paired PK samples with pharmacodynamic (PD) targets of plasma isoprostanoids, CNS glutathione (GSH) and total creatine (tCr) by serial MRS in basal ganglia (BG) before and after NVD infusion at five days. Infants had moderate (n = 14) or severe HIE (n = 16), funisitis (32%), and vitamin D deficiency (75%). NVD resulted in rapid, dose-responsive increases in CNS GSH and tCr that correlated positively with plasma [NAC], inversely with plasma isofurans, and was greater in infants with lower baseline [GSH] and [tCr], suggesting increases in these PD markers were titrated by neural demand. Hypothermia and normothermia altered NAC PK estimates. NVD was well tolerated. Excluding genetic syndromes (2), prolonged ECMO (2), lost-to-follow-up (1) and SIDS death (1), 24 NVD treated HIE infants have no evidence of cerebral palsy, autism or cognitive delay at 24-48 months. These data confirm that low, safe doses of NVD in HIE neonates decreased oxidative stress in plasma and CNS, improved CNS energetics, and are associated with favorable developmental outcomes at two to four years.

Liver injury associated with drug intake during pregnancy

Drug use during pregnancy is not common. Drug-induced liver injury (DILI) is a potential complication that is rare but can adversely affect both the mother and the fetus. Although many drugs can directly cause hepatotoxicity, idiosyncratic liver injury is common in pregnancy. Underreporting of adverse drug reactions, lack of adequate literature regarding drug safety in pregnancy, and the inherent difficulty in diagnosing DILI during pregnancy make the management of this condition challenging. This review attempts to describe the existing literature regarding DILI in pregnancy, which is mainly in the form of case reports; several studies have looked at the safety of antithyroid drugs, antiretroviral drugs, and paracetamol, which have an indication for use in pregnancy; the relevant data from these studies with regard to DILI has been presented. In addition, the review describes the diagnosis of DILI, grading the disease severity, assessment of causality linking the drug to the adverse event, regulatory guidelines for evaluating the potential of drugs to cause liver injury, efforts to ensure better participation of women in clinical trials and studies in pregnant women population in particular, and the challenges involved in generating adequate research evidence. The establishment of DILI registries in various countries is an encouraging development; however, there is a need for promoting active, spontaneous reporting of adverse events during pregnancy to ensure rapid generation of evidence regarding the safety of a drug in pregnant women.

Environmental cadmium exposure during pregnancy causes diabetes-like phenotypes in mouse offspring: Association with oxidative stress in the fetal liver

Cadmium (Cd), a noxious heavy metal, is widespread in the living environment. Gestational exposure to Cd at environmental dose has been shown to cause fetal growth restriction (FGR). However, the long-term effects and the mechanisms underlying environmental Cd exposure on glucose metabolism in offspring remain unclear. Here, we established a murine model to study the impacts of gestational exposure to environmental Cd on glucose metabolism at different life stages of offspring. Results demonstrated that the offspring mice developed hyperglycemia in puberty and impaired glucose tolerance in adulthood following maternal Cd exposure during gestation. Further mechanistic investigation showed that Cd exposure upregulated the expression of key proteins in hepatic gluconeogenesis, including p-CREB, PGC-1α and G6PC, in pubertal and adult offspring. In addition, we demonstrated that Cd exposure during pregnancy markedly elevated the level of oxidative stress-related proteins, including NOX2, NOX4 and HO-1, in the fetal liver. The effects of gestational exposure to N-acetylcysteine (NAC), a free-radical scavenging antioxidant, presented that NAC supplementation alleviated hepatic oxidative stress in fetuses, and thereby reversed hyperglycemia and glucose intolerance in mouse offspring. Collectively, our data suggested that gestational exposure to environmental Cd caused diabetes-like phenotypes via enhancing hepatic gluconeogenesis, which is associated with oxidative stress in fetal livers. This work provides new insights into the protective effects of antioxidants on fetal-originated diabetes triggered by environmental toxicants.

Fetal Neuroprotective Strategies: Therapeutic Agents and Their Underlying Synaptic Pathways

Synaptic signaling is integral for proper brain function. During fetal development, exposure to inflammation or mild hypoxic-ischemic insult may lead to synaptic changes and neurological damage that impairs future brain function. Preterm neonates are most susceptible to these deleterious outcomes. Evaluating clinically used and novel fetal neuroprotective measures is essential for expanding treatment options to mitigate the short and long-term consequences of fetal brain injury. Magnesium sulfate is a clinical fetal neuroprotective agent utilized in cases of imminent preterm birth. By blocking N-methyl-D-aspartate receptors, magnesium sulfate reduces glutamatergic signaling, which alters calcium influx, leading to a decrease in excitotoxicity. Emerging evidence suggests that melatonin and N-acetyl-L-cysteine (NAC) may also serve as novel putative fetal neuroprotective candidates. Melatonin has important anti-inflammatory and antioxidant properties and is a known mediator of synaptic plasticity and neuronal generation. While NAC acts as an antioxidant and a precursor to glutathione, it also modulates the glutamate system. Glutamate excitotoxicity and dysregulation can induce perinatal preterm brain injury through damage to maturing oligodendrocytes and neurons. The improved drug efficacy and delivery of the dendrimer-bound NAC conjugate provides an opportunity for enhanced pharmacological intervention. Here, we review recent literature on the synaptic pathways underlying these therapeutic strategies, discuss the current gaps in knowledge, and propose future directions for the field of fetal neuroprotective agents.

N-Acetylcysteine (NAC): Impacts on Human Health

N-acetylcysteine (NAC) is a medicine widely used to treat paracetamol overdose and as a mucolytic compound. It has a well-established safety profile, and its toxicity is uncommon and dependent on the route of administration and high dosages. Its remarkable antioxidant and anti-inflammatory capacity is the biochemical basis used to treat several diseases related to oxidative stress and inflammation. The primary role of NAC as an antioxidant stems from its ability to increase the intracellular concentration of glutathione (GSH), which is the most crucial biothiol responsible for cellular redox imbalance. As an anti-inflammatory compound, NAC can reduce levels of tumor necrosis factor-alpha (TNF-α) and interleukins (IL-6 and IL-1β) by suppressing the activity of nuclear factor kappa B (NF-κB). Despite NAC's relevant therapeutic potential, in several experimental studies, its effectiveness in clinical trials, addressing different pathological conditions, is still limited. Thus, the purpose of this chapter is to provide an overview of the medicinal effects and applications of NAC to human health based on current therapeutic evidence.

N-acetylcysteine, xCT and suppression of Maxi-chloride channel activity in human placenta

INTRODUCTION

Placental oxidative stress features in pregnancy pathologies but in clinical trials antioxidant supplementation has not improved outcomes. N-acetylcysteine (NAC) stimulates glutathione production and is proposed as a therapeutic agent in pregnancy. However, key elements of N-acetylcysteine biology, including its cellular uptake mechanism, remains unclear. This study explores how the cystine/glutamate transporter xCT may mediate N-acetylcysteine uptake and how N-acetylcysteine alters placental redox status.

METHODS

The involvement of xCT in NAC uptake by the human placenta was studied in perfused placenta and Xenopus oocytes. The effect of short-term N-acetylcysteine exposure on the placental villous proteome was determined using LC-MS. The effect of N-acetylcysteine on Maxi-chloride channel activity was investigated in perfused placenta, villous fragments and cell culture.

RESULTS

Maternoplacental N-acetylcysteine administration stimulated intracellular glutamate efflux suggesting a role of the exchange transporter xCT, which was localised to the microvillous membrane of the placental syncytiotrophoblast. Placental exposure to a bolus of N-acetylcysteine inhibited subsequent activation of the redox sensitive Maxi-chloride channel independently of glutathione synthesis. Stable isotope quantitative proteomics of placental villi treated with N-acetylcysteine demonstrated changes in pathways associated with oxidative stress, apoptosis and the acute phase response.

DISCUSSION

This study suggests that xCT mediates N-acetylcysteine uptake into the placenta and that N-acetylcysteine treatment of placental tissue alters the placental proteome while regulating the redox sensitive Maxi-chloride channel. Interestingly N-acetylcysteine had antioxidant effects independent of the glutathione pathway. Effective placental antioxidant therapy in pregnancy may require maintaining the balance between normalising redox status without inhibiting physiological redox signalling.

NAC and Vitamin D Restore CNS Glutathione in Endotoxin-Sensitized Neonatal Hypoxic-Ischemic Rats

Therapeutic hypothermia does not improve outcomes in neonatal hypoxia ischemia (HI) complicated by perinatal infection, due to well-described, pre-existing oxidative stress and neuroinflammation that shorten the therapeutic window. For effective neuroprotection post-injury, we must first define and then target CNS metabolomic changes immediately after endotoxin-sensitized HI (LPS-HI). We hypothesized that LPS-HI would acutely deplete reduced glutathione (GSH), indicating overwhelming oxidative stress in spite of hypothermia treatment in neonatal rats. Post-natal day 7 rats were randomized to sham ligation, or severe LPS-HI (0.5 mg/kg 4 h before right carotid artery ligation, 90 min 8% O2), followed by hypothermia alone or with N-acetylcysteine (25 mg/kg) and vitamin D (1,25(OH)2D3, 0.05 μg/kg) (NVD). We quantified in vivo CNS metabolites by serial 7T MR Spectroscopy before, immediately after LPS-HI, and after treatment, along with terminal plasma drug concentrations. GSH was significantly decreased in all LPS-HI rats compared with baseline and sham controls. Two hours of hypothermia alone did not improve GSH and allowed glutamate + glutamine (GLX) to increase. Within 1 h of administration, NVD increased GSH close to baseline and suppressed GLX. The combination of NVD with hypothermia rapidly improved cellular redox status after LPS-HI, potentially inhibiting important secondary injury cascades and allowing more time for hypothermic neuroprotection.

Antenatal N-acetylcysteine to improve outcomes of premature infants with intra-amniotic infection and inflammation (Triple I): randomized clinical trial

BACKGROUND

Intrauterine infection and/or inflammation (Triple I) is an important cause of preterm birth (PTB) and adverse newborn outcomes. N-acetylcysteine (NAC) is a Food and Drug Administration (FDA)-approved drug safely administered to pregnant women with acetaminophen toxicity.

METHODS

We conducted a single-center, quadruple-blind, placebo-controlled trial of pregnant women with impending PTB due to confirmed Triple I. Participants (n = 67) were randomized to an intravenous infusion of NAC or placebo mimicking the FDA-approved regimen. Outcomes included clinical measures and mechanistic biomarkers.

RESULTS

Newborns exposed to NAC (n = 33) had significantly improved status at birth and required less intensive resuscitation compared to placebo (n = 34). Fewer NAC-exposed newborns developed two or more prematurity-related severe morbidities [NAC: 21% vs. placebo: 47%, relative risk, 0.45; 95% confidence interval (CI) 0.21-0.95] with the strongest protection afforded against bronchopulmonary dysplasia (BPD, NAC: 3% vs. placebo: 32%, relative risk, 0.10; 95% CI: 0.01-0.73). These effects were independent of gestational age, birth weight, sex, or race. Umbilical cord plasma NAC concentration correlated directly with cysteine, but not with plasma or whole blood glutathione. NAC reduced the placental expression of histone deacetylase-2, suggesting that epigenetic mechanisms may be involved.

CONCLUSIONS

These data provide support for larger studies of intrapartum NAC to reduce prematurity-related morbidity.

IMPACT

In this randomized clinical trial of 65 women and their infants, maternal intravenous NAC employing the FDA-approved dosing protocol resulted in lower composite neonatal morbidity independent of gestational age, race, sex, and birthweight. Administration of NAC in amniocentesis-confirmed Triple I resulted in a remarkably lower incidence of BPD. As prior studies have not shown a benefit of postnatal NAC in ventilated infants, our trial highlights the critical antenatal timing of NAC administration. Repurposing of NAC for intrapartum administration should be explored in larger clinical trials as a strategy to improve prematurity-related outcomes and decrease the incidence of BPD.

Management of clinical chorioamnionitis: an evidence-based approach

This review aimed to examine the existing evidence about interventions proposed for the treatment of clinical chorioamnionitis, with the goal of developing an evidence-based contemporary approach for the management of this condition. Most trials that assessed the use of antibiotics in clinical chorioamnionitis included patients with a gestational age of ≥34 weeks and in labor. The first-line antimicrobial regimen for the treatment of clinical chorioamnionitis is ampicillin combined with gentamicin, which should be initiated during the intrapartum period. In the event of a cesarean delivery, patients should receive clindamycin at the time of umbilical cord clamping. The administration of additional antibiotic therapy does not appear to be necessary after vaginal or cesarean delivery. However, if postdelivery antibiotics are prescribed, there is support for the administration of an additional dose. Patients can receive antipyretic agents, mainly acetaminophen, even though there is no clear evidence of their benefits. Current evidence suggests that the administration of antenatal corticosteroids for fetal lung maturation and of magnesium sulfate for fetal neuroprotection to patients with clinical chorioamnionitis between 24 0/7 and 33 6/7 weeks of gestation, and possibly between 23 0/7 and 23 6/7 weeks of gestation, has an overall beneficial effect on the infant. However, delivery should not be delayed to complete the full course of corticosteroids and magnesium sulfate. Once the diagnosis of clinical chorioamnionitis has been established, delivery should be considered, regardless of the gestational age. Vaginal delivery is the safer option and cesarean delivery should be reserved for standard obstetrical indications. The time interval between the diagnosis of clinical chorioamnionitis and delivery is not related to most adverse maternal and neonatal outcomes. Patients may require a higher dose of oxytocin to achieve adequate uterine activity or greater uterine activity to effect a given change in cervical dilation. The benefit of using continuous electronic fetal heart rate monitoring in these patients is unclear. We identified the following promising interventions for the management of clinical chorioamnionitis: (1) an antibiotic regimen including ceftriaxone, clarithromycin, and metronidazole that provides coverage against the most commonly identified microorganisms in patients with clinical chorioamnionitis; (2) vaginal cleansing with antiseptic solutions before cesarean delivery with the aim of decreasing the risk of endometritis and, possibly, postoperative wound infection; and (3) antenatal administration of N-acetylcysteine, an antioxidant and antiinflammatory agent, to reduce neonatal morbidity and mortality. Well-powered randomized controlled trials are needed to assess these interventions in patients with clinical chorioamnionitis.

Influence of N-acetylcysteine on steroidogenesis and gene expression in porcine placental trophoblast cells

N-acetylcysteine (NAC) is a widely used anti-inflammatory agent and antioxidant in vivo and in vitro. As a nutritional supplement, NAC can improve production and reproductive performances in animals through enhancing placental function and regulating hormone production. Trophoblast proliferation and steroid hormone production are two major functions in the placenta. We hypothesized that the effects of NAC on placental function is due to its direct and indirect effects on gene expression in placental trophoblast cells (pTr). To evaluate this hypothesis, we investigated the effects of NAC on steroidogenesis, gene expression, and cell proliferation in porcine pTr in vitro. pTr were treated with NAC in serum-free medium for 24 h with different concentrations (0, 0.1 μM, 1.0 μM, 10.0 μM, 0.1 mM, 1.0 mM, and 10.0 mM). Low-dose NAC (1 μM) stimulated pTr proliferation and decreased progesterone production, while increasing estradiol production (P < 0.05). High-dose NAC (10 mM) suppressed cell proliferation (P < 0.05), but had no effect on steroidogenesis. Low-dose NAC increased CCDN1 and decreased CASP3 and CASP8 mRNA levels (P < 0.05), whereas high-dose NAC decreased CDK4 and CCDN1 and increased CASP3 mRNA levels (P < 0.05). NAC had no effect on the mRNA abundance of StAR and HSD3B. Low-dose NAC upregulated CYP19A1 mRNA expression, and high-dose NAC downregulated CYP11A1 mRNA abundance (P < 0.05). Only low-dose NAC increased NOS3 mRNA abundance and tetrahydrobiopterin reduction (BH4/BH2 ratio). We conclude that NAC may act directly and indirectly on pTr with a dose-dependent manner and may regulate placental function by affecting pTr differentiation via regulating pTr steroid synthesis, cell proliferation, and apoptosis in sows.

Prophylactic antenatal N-Acetyl Cysteine administration combined with postnatal administration can decrease mortality and injury markers associated with necrotizing enterocolitis in a rat model

BACKGROUND

Necrotizing enterocolitis (NEC) is a devastating gastrointestinal disease of neonates, especially premature neonates. To date, there is no prophylactic treatment against NEC, except breast milk and slow increase in enteral feeding, and there is no antenatal prophylaxis.

AIMS

To assess possible protective effects of antenatal N-Acetyl Cysteine (NAC) against the intestinal pathophysiological changes associated with NEC in a rat model of NEC and against its associated mortality.

METHODS

Newborn Sprague-Dawley rats were divided into 5 groups: control (n = 33); NEC (n = 32)-subjected to hypoxia and formula feeding for 4 days to induce NEC; NEC-NAC (n = 34)-with induced NEC and concomitant postnatal NAC administration; NAC-NEC (n = 33)-born to dams treated with NAC for the last 3 days of pregnancy starting at gestational age of 18 days, and then subjected to induced NEC after birth; NAC-NEC-NAC (n = 36)-subjected to induced NEC with both prenatal and postnatal NAC treatment. At day of life 5, weight and survival of pups in the different groups were examined, and pups were euthanized. Ileal TNF-α, IL-6, IL-1β, IL-10, NFkB p65, iNOS and cleaved caspase 3 protein levels (western blot) and mRNA expression (RT-PCR) were compared between groups.

RESULTS

Pup mortality was significantly reduced in the NAC-NEC-NAC group compared to NEC (11% vs. 34%, P<0.05). Ileal protein levels and mRNA expression of all injury markers tested except IL-10 were significantly increased in NEC compared to control. These markers were significantly reduced in all NAC treatment groups (NEC-NAC, NAC-NEC, and NAC-NEC-NAC) compared to NEC. The most pronounced decrease was observed in the NAC-NEC NAC group.

CONCLUSIONS

Antenatal NAC decreases injury markers and mortality associated with NEC in a rat model. Antenatal administration of NAC may present a novel approach for NEC prophylaxis in pregnancies with risk for preterm birth.

Maternal N-Acetyl Cysteine Intake Improved Glucose Tolerance in Obese Mice Offspring

Exposure to certain environmental factors during the early stages of development was found to affect health in adulthood. Among other environmental factors, oxidative stress has been suggested to be involved in fetal programming, leading to elevated risk for metabolic disorders, including type 2 diabetes; however, the possibility that antioxidant consumption during early life may affect the development of diabetes has scarcely been studied. The aim of this study was to investigate the effects of N-acetyl-l-cysteine (NAC) given during pregnancy and lactation on the susceptibility of offspring to develop glucose intolerance at adulthood. C57bl6/J mice were given NAC during pregnancy and lactation. High fat diet (HFD) was given to offspring at an age of 6 weeks for an additional 9 weeks, till the end of the study. Isolated islets of NAC-treated offspring (6 weeks old, before HFD feeding) had an increased efficacy of glucose-stimulated insulin secretion and a higher resistance to oxidative damage. Following HFD feeding, glucose tolerance and insulin sensitivity of NAC-treated offspring were improved. In addition, islet diameter was lower in male offspring of NAC-treated mice compared to their HFD-fed littermates. NAC consumption during early life improves glucose tolerance in adulthood in mice.

A phase 2 trial of N-Acetylcysteine in Biliary atresia after Kasai portoenterostomy

BACKGROUND

Biliary atresia (BA) is a life-threatening liver disease of infancy, characterized by extrahepatic biliary obstruction, bile retention, and progressive liver injury. The Kasai portoenterostomy (KP) is BA's only nontransplant treatment. Its success is variable and depends on restoration of hepatic bile flow. Many adjunctive therapeutics have been studied to improve outcomes after the KP, but none demonstrate effectiveness. This study tests if N-acetylcysteine (NAC), a precursor to the choleretic glutathione, improves bile flow after KP.

METHODS

This report describes the design of an open-label, single center, Phase 2 study to determine the effect of NAC following KP on markers of bile flow and outcomes in BA. The intervention is intravenous NAC (150 mg/kg/day) administered continuously for seven days starting 0-24 h after KP. The primary outcome is normalization of total serum bile acid (TSBA) concentrations within 24 weeks of KP. The secondary objectives are to describe NAC therapy's effect on other clinical parameters followed in BA for 24 months and to report adverse events occurring with therapy. This study follows the "minimax" clinical trial design.

DISCUSSION

This is the first clinical trial to test NAC's effectiveness in improving bile flow after KP in BA. It introduces three important concepts for future BA therapeutic trials: (1) the "minimax" study design, a pertinent design for rare diseases because it detects potential effects quickly with small subject size; (2) the more sensitive bile flow marker, TSBAs, which may correlate with positive long-term outcomes better than traditional bile flow markers such as serum bilirubin; and (3) liver enzyme changes immediately after KP, which can be a guideline for potential drug-induced liver injury in other BA peri-operative adjunctive therapeutic trials.

Dysregulation of major functional genes in frontal cortex by maternal exposure to carbon black nanoparticle is not ameliorated by ascorbic acid pretreatment

Recent cohort studies have revealed that perinatal exposure to particulate air pollution, including carbon-based nanoparticles, increases the risk of brain disorders. Although developmental neurotoxicity is currently a major issue in the toxicology of nanoparticles, critical information for understanding the mechanisms underlying the developmental neurotoxicity of airway exposure to carbon black nanoparticle (CB-NP) is still lacking. In order to investigate these mechanisms, we comprehensively analyzed fluctuations in the gene expression profile of the frontal cortex of offspring mice exposed maternally to CB-NP, using microarray analysis combined with Gene Ontology information. We also analyzed differences in the enriched function of genes dysregulated by maternal CB-NP exposure with and without ascorbic acid pretreatment to refine specific alterations in gene expression induced by CB-NP. Total of 652 and 775 genes were dysregulated by CB-NP in the frontal cortex of 6- and 12-week-old offspring mice, respectively. Among the genes dysregulated by CB-NP, those related to extracellular matrix structural constituent, cellular response to interferon-beta, muscle organ development, and cysteine-type endopeptidase inhibitor activity were ameliorated by ascorbic acid pretreatment. A large proportion of the dysregulated genes, categorized in hemostasis, growth factor, chemotaxis, cell proliferation, blood vessel, and dopaminergic neurotransmission, were, however, not ameliorated by ascorbic acid pretreatment. The lack of effects of ascorbic acid on the dysregulation of genes following maternal CB-NP exposure suggests that the contribution of oxidative stress to the effects of CB-NP on these biological functions, i.e., cell migration and proliferation, blood vessel maintenance, and dopaminergic neuron system, may be limited. At least, ascorbic acid pretreatment is hardly likely to be able to protect the brain of offspring from developmental neurotoxicity of CB-NP. The present study provides insight into the mechanisms underlying developmental neurotoxicity following maternal nanoparticle exposure.

Oxidative stress in placental pathology

The most important function of the placenta is the exchange of nutrients and oxygen between a mother and her fetus. To establish a healthy functioning placenta, placentation needs to occur with adequate remodelling of spiral arteries by extravillous trophoblasts. When this process is impaired, the resulting suboptimal and inadequate placenta function results in the manifestation of pregnancy complications. Impaired placenta function can cause preeclampsia and leads to fetal growth restriction due to hypoxia. Presence of hypoxia leads to oxidative stress due to an imbalance between reactive oxygen species and antioxidants, thereby causing damage to proteins, lipids and DNA. In the placenta, signs of morphological adaptation in response to hypoxia can be found. Different placental lesions like maternal or fetal vascular malperfusion or chronic villitis lead to a decreased exchange of oxygen between the mother and the fetus. Clinically, several biomarkers indicative for oxidative stress, e.g. malondialdehyde and reduced levels of free thiols are found. This review aims to give an overview of the causes and (potential) role of placental oxidative stress in the development of placental parenchymal pathology and its clinical consequences. Also, therapeutic options aiming at prevention or treatment of hypoxia of the placenta and fetus are described.

Systematic Review of Human and Animal Studies Examining the Efficacy and Safety of N-Acetylcysteine (NAC) and N-Acetylcysteine Amide (NACA) in Traumatic Brain Injury: Impact on Neurofunctional Outcome and Biomarkers of Oxidative Stress and Inflammation

Background

No new therapies for traumatic brain injury (TBI) have been officially translated into current practice. At the tissue and cellular level, both inflammatory and oxidative processes may be exacerbated post-injury and contribute to further brain damage. N-acetylcysteine (NAC) has the potential to downregulate both processes. This review focuses on the potential neuroprotective utility of NAC and N-acetylcysteine amide (NACA) post-TBI.

Methods

Medline, Embase, Cochrane Library, and ClinicalTrials.gov were searched up to July 2017. Studies that examined clinical and laboratory effects of NAC and NACA post-TBI in human and animal studies were included. Risk of bias was assessed in human and animal studies according to the design of each study (randomized or not). The primary outcome assessed was the effect of NAC/NACA treatment on functional outcome, while secondary outcomes included the impact on biomarkers of inflammation and oxidation. Due to the clinical and methodological heterogeneity observed across studies, no meta-analyses were conducted.

Results

Our analyses revealed only three human trials, including two randomized controlled trials (RCTs) and 20 animal studies conducted using standardized animal models of brain injury. The two RCTs reported improvement in the functional outcome post-NAC/NACA administration. Overall, the evidence from animal studies is more robust and demonstrated substantial improvement of cognition and psychomotor performance following NAC/NACA use. Animal studies also reported significantly more cortical sparing, reduced apoptosis, and lower levels of biomarkers of inflammation and oxidative stress. No safety concerns were reported in any of the studies included in this analysis.

Conclusion

Evidence from the animal literature demonstrates a robust association for the prophylactic application of NAC and NACA post-TBI with improved neurofunctional outcomes and downregulation of inflammatory and oxidative stress markers at the tissue level. While a growing body of scientific literature suggests putative beneficial effects of NAC/NACA treatment for TBI, the lack of well-designed and controlled clinical investigations, evaluating therapeutic outcomes, prognostic biomarkers, and safety profiles, limits definitive interpretation and recommendations for its application in humans at this time.

Maternal dendrimer-based therapy for inflammation-induced preterm birth and perinatal brain injury

Preterm birth is a major risk factor for adverse neurological outcomes in ex-preterm children, including motor, cognitive, and behavioral disabilities. N-acetyl-L-cysteine therapy has been used in clinical studies; however, it requires doses that cause significant side effects. In this study, we explore the effect of low dose N-acetyl-L-cysteine therapy, delivered using a targeted, systemic, maternal, dendrimer nanoparticle (DNAC), in a mouse model of intrauterine inflammation. Our results demonstrated that intraperitoneal maternal DNAC administration significantly reduced the preterm birth rate and altered placental immune profile with decreased CD8⁺ T-cell infiltration. Furthermore, we demonstrated that DNAC improved neurobehavioral outcomes and reduced fetal neuroinflammation and long-term microglial activation in offspring. Our study is the first to provide evidence for the role of CD8⁺ T-cell in the maternal-fetal interface during inflammation and further support the efficacy of DNAC in preventing preterm birth and prematurity-related outcomes.

Phase I randomized clinical trial of N-acetylcysteine in combination with an adjuvant probenecid for treatment of severe traumatic brain injury in children

Background

There are no therapies shown to improve outcome after severe traumatic brain injury (TBI) in humans, a leading cause of morbidity and mortality. We sought to verify brain exposure of the systemically administered antioxidant N-acetylcysteine (NAC) and the synergistic adjuvant probenecid, and identify adverse effects of this drug combination after severe TBI in children.

Methods

IRB-approved, randomized, double-blind, placebo controlled Phase I study in children 2 to 18 years-of-age admitted to a Pediatric Intensive Care Unit after severe TBI (Glasgow Coma Scale [GCS] score ≤8) requiring an externalized ventricular drain for measurement of intracranial pressure (ICP). Patients were recruited from November 2011-August 2013. Fourteen patients (n = 7/group) were randomly assigned after obtaining informed consent to receive probenecid (25 mg/kg load, then 10 mg/kg/dose q6h×11 doses) and NAC (140 mg/kg load, then 70 mg/kg/dose q4h×17 doses), or placebos via naso/orogastric tube. Serum and CSF samples were drawn pre-bolus and 1–96 h after randomization and drug concentrations were measured via UPLC-MS/MS. Glasgow Outcome Scale (GOS) score was assessed at 3 months.

Results

There were no adverse events attributable to drug treatment. One patient in the placebo group was withdrawn due to adverse effects. In the treatment group, NAC concentrations ranged from 16,977.3±2,212.3 to 16,786.1±3,285.3 in serum and from 269.3±113.0 to 467.9±262.7 ng/mL in CSF, at 24 to 72 h post-bolus, respectively; and probenecid concentrations ranged from 75.4.3±10.0 to 52.9±25.8 in serum and 5.4±1.0 to 4.6±2.1 μg/mL in CSF, at 24 to 72 h post-bolus, respectively (mean±SEM). Temperature, mean arterial pressure, ICP, use of ICP-directed therapies, surveillance serum brain injury biomarkers, and GOS at 3 months were not different between groups.

Conclusions

Treatment resulted in detectable concentrations of NAC and probenecid in CSF and was not associated with undesirable effects after TBI in children.

Trial registration

ClinicalTrials.gov NCT01322009

N-Acetylcysteine, a glutathione precursor, reverts vascular dysfunction and endothelial epigenetic programming in intrauterine growth restricted guinea pigs

KEY POINTS

Intrauterine growth restriction (IUGR) is associated with vascular dysfunction, oxidative stress and signs of endothelial epigenetic programming of the umbilical vessels. There is no evidence that this epigenetic programming is occurring on systemic fetal arteries. In IUGR guinea pigs we studied the functional and epigenetic programming of endothelial nitric oxide synthase (eNOS) (Nos3 gene) in umbilical and systemic fetal arteries, addressing the role of oxidative stress in this process by maternal treatment with N-acetylcysteine (NAC) during the second half of gestation. The present study suggests that IUGR endothelial cells have common molecular markers of programming in umbilical and systemic arteries. Notably, maternal treatment with NAC restores fetal growth by increasing placental efficiency and reverting the functional and epigenetic programming of eNOS in arterial endothelium in IUGR guinea pigs.

ABSTRACT

In humans, intrauterine growth restriction (IUGR) is associated with vascular dysfunction, oxidative stress and signs of endothelial programming in umbilical vessels. We aimed to determine the effects of maternal antioxidant treatment with N-acetylcysteine (NAC) on fetal endothelial function and endothelial nitric oxide synthase (eNOS) programming in IUGR guinea pigs. IUGR was induced by implanting ameroid constrictors on uterine arteries of pregnant guinea pigs at mid gestation, half of the sows receiving NAC in the drinking water (from day 34 until term). Fetal biometry and placental vascular resistance were followed by ultrasound throughout gestation. At term, umbilical arteries and fetal aortae were isolated to assess endothelial function by wire-myography. Primary cultures of endothelial cells (ECs) from fetal aorta, femoral and umbilical arteries were used to determine eNOS mRNA levels by quantitative PCR and analyse DNA methylation in the Nos3 promoter by pyrosequencing. Doppler ultrasound measurements showed that NAC reduced placental vascular resistance in IUGR (P < 0.05) and recovered fetal weight (P < 0.05), increasing fetal-to-placental ratio at term (∼40%) (P < 0.001). In IUGR, NAC treatment restored eNOS-dependent relaxation in aorta and umbilical arteries (P < 0.05), normalizing eNOS mRNA levels in EC fetal and umbilical arteries (P < 0.05). IUGR-derived ECs had a decreased DNA methylation (∼30%) at CpG -170 (from the transcription start site) and this epigenetic signature was absent in NAC-treated fetuses (P < 0.001). These data show that IUGR-ECs have common molecular markers of eNOS programming in umbilical and systemic arteries and this effect is prevented by maternal treatment with antioxidants.

Preclinical evaluation of drugs to block inflammation-driven preterm birth

Intrauterine inflammation, the major cause of early preterm birth, can have microbial and sterile aetiologies. We assessed in a Transwell model the anti-inflammatory efficacies of five drugs on human extraplacental membranes delivered after preterm spontaneous labour (30-34 wk). Drugs [TPCA1 (IKKβ inhibitor), 5 z-7-oxozeaenol (OxZ, TAK1 inhibitor), inhibitor of NF-κB essential modulator binding domain (iNBD), SB239063 (p38 MAPK inhibitor) and N-acetyl cysteine (free radical scavenger free radicals)] were added after 12 h equilibration to the amniotic compartment. Concentrations of IL-6, TNF-α, MCP-1, IL-1β and PGE₂ in the media, and IL6, TNFA and PTGS2 mRNA expression levels in membranes, were determined after 12 h. Data were analysed using mixed models analyses. Thirteen of the 28 membranes had histological chorioamnionitis (HCA⁺); five were positive for bacterial culture and six for fetal inflammatory reaction. Baseline PGE₂ and cytokine production was similar between HCA^- and HCA⁺ membranes. Anti-inflammatory effects were also similar between HCA^- and HCA⁺ membranes. TPCA1 and OxZ were the most effective drugs; each inhibited amniotic secretion of 4/5 pro-inflammatory mediators and mRNA levels of 2/3, regardless of stimulus. We conclude that treatment with TPCA1 or OxZ, in combination with antibiotics, may minimise the adverse effects of intrauterine inflammation in pregnancy.

Fetal and Neonatal Effects of N-Acetylcysteine When Used for Neuroprotection in Maternal Chorioamnionitis

OBJECTIVE

To evaluate the clinical safety of antenatal and postnatal N-acetylcysteine (NAC) as a neuroprotective agent in maternal chorioamnionitis in a randomized, controlled, double-blinded trial.

STUDY DESIGN

Twenty-two mothers >24 weeks gestation presenting within 4 hours of diagnosis of clinical chorioamnionitis were randomized with their 24 infants to NAC or saline treatment. Antenatal NAC (100 mg/kg/dose) or saline was given intravenously every 6 hours until delivery. Postnatally, NAC (12.5-25 mg/kg/dose, n = 12) or saline (n = 12) was given every 12 hours for 5 doses. Doppler studies of fetal umbilical and fetal and infant cerebral blood flow, cranial ultrasounds, echocardiograms, cerebral oxygenation, electroencephalograms, and serum cytokines were evaluated before and after treatment, and 12, 24, and 48 hours after birth. Magnetic resonance spectroscopy and diffusion imaging were performed at term age equivalent. Development was followed for cerebral palsy or autism to 4 years of age.

RESULTS

Cardiovascular measures, cerebral blood flow velocity and vascular resistance, and cerebral oxygenation did not differ between treatment groups. Cerebrovascular coupling was disrupted in infants with chorioamnionitis treated with saline but preserved in infants treated with NAC, suggesting improved vascular regulation in the presence of neuroinflammation. Infants treated with NAC had higher serum anti-inflammatory interleukin-1 receptor antagonist and lower proinflammatory vascular endothelial growth factor over time vs controls. No adverse events related to NAC administration were noted.

CONCLUSIONS

In this cohort of newborns exposed to chorioamnionitis, antenatal and postnatal NAC was safe, preserved cerebrovascular regulation, and increased an anti-inflammatory neuroprotective protein.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT00724594.

Systemic dendrimer-drug treatment of ischemia-induced neonatal white matter injury

Extreme prematurity is a major risk factor for perinatal and neonatal brain injury, and can lead to white matter injury that is a precursor for a number of neurological diseases, including cerebral palsy (CP) and autism. Neuroinflammation, mediated by activated microglia and astrocytes, is implicated in the pathogenesis of neonatal brain injury. Therefore, targeted drug delivery to attenuate neuroinflammation may greatly improve therapeutic outcomes in models of perinatal white matter injury. In this work, we use a mouse model of ischemia-induced neonatal white matter injury to study the biodistribution of generation 4, hydroxyl-functionalized polyamidoamine dendrimers. Following systemic administration of the Cy5-labeled dendrimer (D-Cy5), we demonstrate dendrimer uptake in cells involved in ischemic injury, and in ongoing inflammation, leading to secondary injury. The sub-acute response to injury is driven by astrocytes. Within five days of injury, microglial proliferation and migration occurs, along with limited differentiation of oligodendrocytes and oligodendrocyte death. From one day to five days after injury, a shift in dendrimer co-localization occurred. Initially, dendrimer predominantly co-localized with astrocytes, with a subsequent shift towards microglia. Co-localization with oligodendrocytes reduced over the same time period, demonstrating a region-specific uptake based on the progression of the injury. We further show that systemic administration of a single dose of dendrimer-N-acetyl cysteine conjugate (D-NAC) at either sub-acute or delayed time points after injury results in sustained attenuation of the 'detrimental' pro-inflammatory response up to 9days after injury, while not impacting the 'favorable' anti-inflammatory response. The D-NAC therapy also led to improvement in myelination, suggesting reduced white matter injury. Demonstration of treatment efficacy at later time points in the postnatal period provides a greater understanding of how microglial activation and chronic inflammation can be targeted to treat neonatal brain injury. Importantly, it may also provide a longer therapeutic window.

An animal model for chorioamnionitis at term

OBJECTIVE

The purpose of this study was to develop an animal model for intrapartum inflammation at term to investigate the interactions between maternal and fetal inflammatory responses and adverse neurologic outcome.

STUDY DESIGN

Lipopolysaccharide (160, 320, or 640 μg/kg) was administered intraperitoneally to day 20 term-pregnant Sprague Dawley rat dams 2, 4, and 6 hours before sample collection. Maternal outcomes included dam core temperature and plasma interleukin 6 (IL-6). Fetal outcomes included plasma IL-6, brain IL-6 messenger RNA expression, and brain IL-6 protein expression. Primary cortical cell cultures were prepared to examine neuronal morphologic condition. Neurite counts were obtained with the use of automated Sholl analysis.

RESULTS

Maternal plasma IL-6 levels peaked 2 hours after lipopolysaccharide stimulus and rapidly resolved, except for an observed low level persistence at 6 hours with 640 μg/kg. Fetal plasma and placental IL-6 expression also peaked rapidly but only persisted in placental samples. Fetal brain IL-6 RNA and protein expression was significantly higher than control litters at 6 hours after the exposure to both 320 μg/kg (P ≤ .05) and 640 μg/kg (P ≤ .01). Cortical cells from fetuses that were exposed for 6 hours to maternal systemic inflammation showed reduced neurite number and neurite length (P < .001) with increasing lipopolysaccharide dose.

CONCLUSION

Our results demonstrate that fetal brain injury follows isolated systemic maternal inflammation and that fetal brain inflammation lags after maternal stimulus, which creates a potential 4-hour clinical window for therapeutic intervention.

N-acetylcysteine treatment ameliorates the skeletal phenotype of a mouse model of diastrophic dysplasia

Diastrophic dysplasia (DTD) is a recessive chondrodysplasia caused by mutations in SLC26A2, a cell membrane sulfate-chloride antiporter. Sulfate uptake impairment results in low cytosolic sulfate, leading to cartilage proteoglycan (PG) undersulfation. In this work, we used the dtd mouse model to study the role of N-acetyl-l-cysteine (NAC), a well-known drug with antioxidant properties, as an intracellular sulfate source for macromolecular sulfation. Because of the important pre-natal phase of skeletal development and growth, we administered 30 g/l NAC in the drinking water to pregnant mice to explore a possible transplacental effect on the fetuses. When cartilage PG sulfation was evaluated by high-performance liquid chromatography disaccharide analysis in dtd newborn mice, a marked increase in PG sulfation was observed in newborns from NAC-treated pregnancies when compared with the placebo group. Morphometric studies of the femur, tibia and ilium after skeletal staining with alcian blue and alizarin red indicated a partial rescue of abnormal bone morphology in dtd newborns from treated females, compared with pups from untreated females. The beneficial effect of increased macromolecular sulfation was confirmed by chondrocyte proliferation studies in cryosections of the tibial epiphysis by proliferating cell nuclear antigen immunohistochemistry: the percentage of proliferating cells, significantly reduced in the placebo group, reached normal values in dtd newborns from NAC-treated females. In conclusion, NAC is a useful source of sulfate for macromolecular sulfation in vivo when extracellular sulfate supply is reduced, confirming the potential of therapeutic approaches with thiol compounds to improve skeletal deformity and short stature in human DTD and related disorders.

Kinematic measurement of 12-week head control correlates with 12-month neurodevelopment in preterm infants

BACKGROUND

Although new interventions treating neonatal brain injury show great promise, our current ability to predict clinical functional outcomes is poor. Quantitative biomarkers of long-term neurodevelopmental outcome are critically needed to gauge treatment efficacy. Kinematic measures derived from commonly used developmental tasks may serve as early objective markers of future motor outcomes.

AIM

To develop reliable kinematic markers of head control at 12week corrected gestational age (CGA) from two motor tasks: head lifting in prone and pull-to-sit.

STUDY DESIGN AND SUBJECTS

Prospective observational study of 22 preterm infants born between 24 and 34weeks of gestation.

OUTCOME MEASURES

Bayley Scales of Infant Development III (Bayley) motor scores.

RESULTS

Intrarater and interrater reliability of prone head lift angles and pull-to-sit head angles were excellent. Prone head lift angles at 12week CGA correlated with white matter NAA/Cho, concurrent Test of Infant Motor Performance (TIMP) scores, and 12-month Bayley motor scores. Head angles during pull-to-sit at 12-week CGA correlated with TIMP scores.

CONCLUSIONS

Poor ability to lift the head in prone and an inability to align the head with the trunk during the pull-to-sit task were associated with poorer future motor outcome scores. Kinematic measurements of head control in early infancy may serve as reliable objective quantitative markers of future motor impairment and neurodevelopmental outcome.