Prenatal acetaminophen induces liver toxicity in dams, reduces fetal liver stem cells, and increases airway inflammation in adult offspring

A quantitative weight-of-evidence review of preclinical studies examining the potential developmental and reproductive toxicity of acetaminophen

We previously developed a quantitative weight-of-evidence (QWoE) framework using prespecified scoring criteria for preclinical acetaminophen data to characterize potential developmental neurotoxicity outcomes with considerations for biological relevance of the response to adverse outcomes and the strength of methods and study design. The current analysis uses this framework to characterize potential developmental and reproductive toxicity (DART) outcomes following exposure to acetaminophen. Two-hundred forty-two QWoE entries were documented from in vivo rodent studies identified in 110 publications across five categories: DART endpoints in the context of (1) periadolescent/adulthood (nonpregnancy) exposures; (2) pregnant female exposures; and, for in utero or other developmental exposures, (3) anatomical abnormalities, (4) reproductive development, and (5) other physical development. A mean outcome score and methods score were calculated for 242 QWoE entries. Data analyzed in our framework were of moderate quality showing no consistent evidence of DART in male and female rodents following exposure to acetaminophen at therapeutic and/or non-systemically toxic doses. Similar results were found for the individual context- and outcome-related endpoint analyses and as segregated by sex. Overall, this QWoE analysis on the in vivo rodent data demonstrated no consistent evidence of adverse effects following exposure to therapeutic and/or non-systemically toxic acetaminophen on development or on the structure and function of the reproductive system.

Beyond defence: Immune architects of ovarian health and disease

Throughout the individual's reproductive period of life the ovary undergoes continues changes, including cyclic processes of cell death, tissue regeneration, proliferation, and vascularization. Tissue-resident leucocytes particularly macrophages, play a crucial role in shaping ovarian function and maintaining homeostasis. Macrophages crucially promote angiogenesis in the follicles and corpora lutea, thereby supporting steroidogenesis. Recent research on macrophage origins and early tissue seeding has unveiled significant insights into their role in early organogenesis, e.g. in the testis. Here, we review evidence about the prenatal ovarian seeding of leucocytes, primarily macrophages with angiogenic profiles, and its connection to gametogenesis. In the prenatal ovary, germ cells proliferate, form cysts, and undergo changes that, following waves of apoptosis, give rice to the oocytes contained in primordial follicles. These follicles constitute the ovarian reserve that lasts throughout the female's reproductive life. Simultaneously, yolk-sac-derived primitive macrophages colonizing the early ovary are gradually replaced or outnumbered by monocyte-derived fetal macrophages. However, the cues indicating how macrophage colonization and follicle assembly are related are elusive. Macrophages may contribute to organogenesis by promoting early vasculogenesis. Whether macrophages contribute to ovarian lymphangiogenesis or innervation is still unknown. Ovarian organogenesis and gametogenesis are vulnerable to prenatal insults, potentially programming dysfunction in later life, as observed in polycystic ovary syndrome. Experimental and, more sparsely, epidemiological evidence suggest that adverse stimuli during pregnancy can program defective folliculogenesis or a diminished follicle reserve in the offspring. While the ovary is highly sensitive to inflammation, the involvement of local immune responses in programming ovarian health and disease remains to be thoroughly investigated.

Potential adverse actions of prenatal exposure of acetaminophen to offspring

Acetaminophen (APAP) is a widely used as analgesic and antipyretic drug. APAP is also added as an active ingredient in various medications to relieve pain and reduce fever. APAP has been widely used in pregnant women in the past decades because it is considered a relatively safe drug with recommended dose in different countries. However, an increasing number of epidemiological and experimental studies have shown that APAP exposure during pregnancy may increase the risk of inducing reproductive and neurobehavior dysfunctions, hepatotoxicity in offspring. This review aims to assess the potential effects of prenatal APAP exposure on offspring growth and development.

Developmental toxicity and programming alterations of multiple organs in offspring induced by medication during pregnancy

Medication during pregnancy is widespread, but there are few reports on its fetal safety. Recent studies suggest that medication during pregnancy can affect fetal morphological and functional development through multiple pathways, multiple organs, and multiple targets. Its mechanisms involve direct ways such as oxidative stress, epigenetic modification, and metabolic activation, and it may also be indirectly caused by placental dysfunction. Further studies have found that medication during pregnancy may also indirectly lead to multi-organ developmental programming, functional homeostasis changes, and susceptibility to related diseases in offspring by inducing fetal intrauterine exposure to too high or too low levels of maternal-derived glucocorticoids. The organ developmental toxicity and programming alterations caused by medication during pregnancy may also have gender differences and multi-generational genetic effects mediated by abnormal epigenetic modification. Combined with the latest research results of our laboratory, this paper reviews the latest research progress on the developmental toxicity and functional programming alterations of multiple organs in offspring induced by medication during pregnancy, which can provide a theoretical and experimental basis for rational medication during pregnancy and effective prevention and treatment of drug-related multiple fetal-originated diseases.

Racial disparities in liver cancer: Evidence for a role of environmental contaminants and the epigenome

Liver cancer incidence has tripled since the early 1980s, making this disease one of the fastest rising types of cancer and the third leading cause of cancer-related deaths worldwide. In the US, incidence varies by geographic location and race, with the highest incidence in the southwestern and southeastern states and among racial minorities such as Hispanic and Black individuals. Prognosis is also poorer among these populations. The observed ethnic disparities do not fully reflect differences in the prevalence of risk factors, e.g., for cirrhosis that may progress to liver cancer or from genetic predisposition. Likely substantial contributors to risk are environmental factors, including chemical and non-chemical stressors; yet, the paucity of mechanistic insights impedes prevention efforts. Here, we review the current literature and evaluate challenges to reducing liver cancer disparities. We also discuss the hypothesis that epigenetic mediators may provide biomarkers for early detection to support interventions that reduce disparities.

Paracetamol use during pregnancy - a call for precautionary action

Paracetamol (N-acetyl-p-aminophenol (APAP), otherwise known as acetaminophen) is the active ingredient in more than 600 medications used to relieve mild to moderate pain and reduce fever. APAP is widely used by pregnant women as governmental agencies, including the FDA and EMA, have long considered APAP appropriate for use during pregnancy when used as directed. However, increasing experimental and epidemiological research suggests that prenatal exposure to APAP might alter fetal development, which could increase the risks of some neurodevelopmental, reproductive and urogenital disorders. Here we summarize this evidence and call for precautionary action through a focused research effort and by increasing awareness among health professionals and pregnant women. APAP is an important medication and alternatives for treatment of high fever and severe pain are limited. We recommend that pregnant women should be cautioned at the beginning of pregnancy to: forego APAP unless its use is medically indicated; consult with a physician or pharmacist if they are uncertain whether use is indicated and before using on a long-term basis; and minimize exposure by using the lowest effective dose for the shortest possible time. We suggest specific actions to implement these recommendations. This Consensus Statement reflects our concerns and is currently supported by 91 scientists, clinicians and public health professionals from across the globe.

Paracetamol (Acetaminophen) and the Developing Brain

Paracetamol is commonly used to treat fever and pain in pregnant women, but there are growing concerns that this may cause attention deficit hyperactivity disorder and autism spectrum disorder in the offspring. A growing number of epidemiological studies suggests that relative risks for these disorders increase by an average of about 25% following intrauterine paracetamol exposure. The data analyzed point to a dose-effect relationship but cannot fully account for unmeasured confounders, notably indication and genetic transmission. Only few experimental investigations have addressed this issue. Altered behavior has been demonstrated in offspring of paracetamol-gavaged pregnant rats, and paracetamol given at or prior to day 10 of life to newborn mice resulted in altered locomotor activity in response to a novel home environment in adulthood and blunted the analgesic effect of paracetamol given to adult animals. The molecular mechanisms that might mediate these effects are unknown. Paracetamol has diverse pharmacologic actions. It reduces prostaglandin formation via competitive inhibition of the peroxidase moiety of prostaglandin H2 synthase, while its metabolite N-arachidonoyl-phenolamine activates transient vanilloid-subtype 1 receptors and interferes with cannabinoid receptor signaling. The metabolite N-acetyl-p-benzo-quinone-imine, which is pivotal for liver damage after overdosing, exerts oxidative stress and depletes glutathione in the brain already at dosages below the hepatic toxicity threshold. Given the widespread use of paracetamol during pregnancy and the lack of safe alternatives, its impact on the developing brain deserves further investigation.

Toxicological Property of Acetaminophen: The Dark Side of a Safe Antipyretic/Analgesic Drug?

Acetaminophen (paracetamol, N-acetyl-p-aminophenol; APAP) is the most popular analgesic/antipyretic agent in the world. APAP has been regarded as a safer drug compared with non-steroidal anti-inflammatory drugs (NSAIDs) particularly in terms of lower risks of renal dysfunction, gastrointestinal injury, and asthma/bronchospasm induction, even in high-risk patients such as the elderly, children, and pregnant women. On the other hand, the recent increasing use of APAP has raised concerns about its toxicity. In this article, we review recent pharmacological and toxicological findings about APAP from basic, clinical, and epidemiological studies, including spontaneous drug adverse events reporting system, especially focusing on drug-induced asthma and pre-and post-natal closure of ductus arteriosus. Hepatotoxicity is the greatest fault of APAP and the most frequent cause of drug-induced acute liver failure in Western countries. However, its precise mechanism remains unclear and no effective cure beyond N-acetylcysteine has been developed. Recent animal and cellular studies have demonstrated that some cellular events, such as c-jun N-terminal kinase (JNK) pathway activation, endoplasmic reticulum (ER) stress, and mitochondrial oxidative stress may play important roles in the development of hepatitis. Herein, the molecular mechanisms of APAP hepatotoxicity are summarized. We also discuss the not-so-familiar "dark side" of APAP as an otherwise safe analgesic/antipyretic drug.

Overdoses of Acetaminophen Disrupt the Thyroid-Liver Axis in Neonatal Rats

OBJECTIVE

The aim of the study was to examine the impact of neonatal acetaminophen (APAP; paracetamol) administrations on the thyroid-liver axis in male Wistar rats.

METHODS

APAP (100 or 350mg/kg) was orally administered to neonates from Postnatal Day (PND) 20 to 40.

RESULTS

Both APAP doses elicited a substantial increase in serum TSH, albumin, AST, ALT, and ALP values, and a profound decrease in serum FT4 and FT3 values at PND 40 relative to those in the control group. Additionally, the hypothyroid state in both APAP-treated groups may increase the histopathological variations in the neonatal liver, such as destructive degeneration, fibrosis, fatty degeneration, fibroblast proliferation, haemorrhage, oedema, and vacuolar degeneration, at PND 40. Moreover, in the APAP groups, a marked depression was recorded in the t-SH and GSH levels and GPx and CAT activities at PND 40 in the neonatal liver compared to those in the control group. However, the levels of hepatic LPO, H2O2, and NO were increased in both APAP-treated groups at PND 40. All previous alterations were dose- dependent.

CONCLUSION

Neonatal APAP caused a hypothyroidism and disturbed hepatic cellular components by increasing prooxidant markers and decreasing antioxidant markers, causing hepatotoxicity. Thus, neonatal administrations of APAP may act as a neonatal thyroid-liver disruptor.

Prescribed analgesics in pregnancy and risk of childhood asthma

Many epidemiological studies have reported a positive association between prenatal exposure to paracetamol and childhood wheezing and asthma. We investigated whether the link between prenatal analgesic exposure and asthma/wheeze is specific to paracetamol, and whether it is causal or confounded.Using linked Swedish health register data we investigated the relation between various prescribed analgesics in pregnancy and the risk of childhood asthma/wheeze in a population of 492 999, and used negative paternal control and sibling comparison approaches to explore unmeasured confounding.After controlling for potential confounders, prescribed opioids, antimigraine drugs and paracetamol were all positively associated with childhood asthma/wheeze risk at all ages (e.g. for asthma/wheeze at age 4 years: adjusted OR 1.39 (95% CI 1.30-1.49), 1.19 (95% CI 1.01-1.40) and 1.47 (95% CI 1.36-1.59) for opioids, antimigraine drugs and paracetamol, respectively). The results of the paternal control analysis did not suggest the presence of unmeasured confounding by genetics or shared environment. However, the sibling control analysis broadly suggested that associations between prenatal exposure to the analgesics and asthma/wheeze were confounded by specific maternal factors (e.g. for asthma/wheeze at age 4 years: adjusted OR 0.91 (95% CI 0.62-1.31), 0.50 (95% CI 0.17-1.45) and 0.80 (95% CI 0.50-1.29) for opioids, antimigraine drugs and paracetamol, respectively).We propose that analgesic use in pregnancy does not cause childhood asthma/wheeze and that the association is confounded by unmeasured factors that are intrinsic to the mother, such as chronic pain or anxiety.

Follow-up study of the early, randomised paracetamol trial to preterm infants, found no adverse reactions at the two-years corrected age

AIM

We examined the long-term outcomes and safety of early intravenous paracetamol for ductus arteriosus closure at a corrected age of two years.

METHODS

This was a follow-up of the 2013-2014 randomised, double-blind Preterm Infant's Paracetamol Study at Oulu University Hospital, Finland, which recruited 48 very preterm infants within 24 hours of birth. They received intravenous paracetamol or a placebo for four days. In 2015-2017, we followed up 44 infants (92%) at two years of corrected age. This included clinical and neurodevelopmental assessments and a parental medical history questionnaire.

RESULTS

The 44 infants (55% boys) were born at 23⁵ -31⁶ weeks of gestation. No differences in the cardiac parameters, including blood pressures and ultrasound scan results, were found. Neurodevelopmental stages, as quantified by the Griffiths test, were similar. No signs of autism were reported. Asthma medication was more common in the control group, but the difference was not significant. Atopy scores, numbers of infections and the use of public health services were similar between the two groups.

CONCLUSION

No long-term adverse reactions of early intravenous paracetamol were detected two years later. Larger trials are needed on the safety and efficacy of paracetamol prophylaxis for early ductal closure in very preterm infants.

Elevated metabolites of acetaminophen in cord blood of children with obesity

BACKGROUND

High-throughput metabolomics has been used cross-sectionally to evaluate differential metabolic profiles associated with human obesity.

OBJECTIVES

This study longitudinally assessed the cord blood metabolome to explore if metabolic signatures of obesity at age 3-5 are apparent at birth.

METHODS

In a nested case-control design, metabolomics analysis was performed on umbilical cord blood of 25 children who developed obesity by age 3-5 years, compared with 25 sex-matched non-obese children enrolled as part of an ongoing birth cohort. Logistic regression models were used to identify significant metabolites, adjusting for maternal pre-pregnancy obesity.

RESULTS

Children who had obesity by age 3-5 years had elevated levels of medium and long chain fatty acids including stearate, oleate and palmitate at birth. Children with obesity were also more likely to have elevated levels of acetaminophen metabolites at birth, specifically: 3-(N-acetyl-L-cystein-S-yl) acetaminophen, 2-hydroxyacetaminophen sulfate, 2-methoxyacetaminophen glucuronide and p-acetamidophenyl glucuronide.

CONCLUSION

Although the observed increases in lipids are consistent with previous metabolomic studies of obesity, this study is the first to report associations between acetaminophen metabolites and obesity in children; however, we lack mechanistic insights for this link. Larger human studies with longer follow-up and laboratory-controlled animal experiments are needed to clarify associations.

Long-term adverse effects of paracetamol - a review

Paracetamol (acetaminophen) is the most commonly used drug in the world, with a long record of use in acute and chronic pain. In recent years, the benefits of paracetamol use in chronic conditions has been questioned, notably in the areas of osteoarthritis and lower back pain. Over the same period, concerns over the long-term adverse effects of paracetamol use have increased, initially in the field of hypertension, but more recently in other areas as well. The evidence base for the adverse effects of chronic paracetamol use consists of many cohort and observational studies, with few randomized controlled trials, many of which contradict each other, so these studies must be interpreted with caution. Nevertheless, there are some areas where the evidence for harm is more robust, and if a clinician is starting paracetamol with the expectation of chronic use it might be advisable to discuss these side effects with patients beforehand. In particular, an increased risk of gastrointestinal bleeding and a small (~4 mmHg) increase in systolic blood pressure are adverse effects for which the evidence is particularly strong, and which show a degree of dose dependence. As our estimation of the benefits decreases, an accurate assessment of the harms is ever more important. The present review summarizes the current evidence on the harms associated with chronic paracetamol use, focusing on cardiovascular disease, asthma and renal injury, and the effects of in utero exposure.

Extrahepatic toxicity of acetaminophen: critical evaluation of the evidence and proposed mechanisms

Research on acetaminophen (APAP) toxicity over the last several decades has focused on the pathophysiology of liver injury, but increasingly attention is paid to other known and possible adverse effects. It has been known for decades that APAP causes acute kidney injury, but confusion exists regarding prevalence, and the mechanisms have not been well investigated. More recently, evidence for pulmonary, endocrine, neurological, and neurodevelopmental toxicity has been reported in a number of published experimental, clinical, and epidemiological studies, but the quality of those studies has varied. It is important to view those data critically due to implications for regulation and clinical practice. Here, we review evidence and proposed mechanisms for extrahepatic adverse effects of APAP and weigh weaknesses and strengths in the available data.

Paracetamol Medication During Pregnancy: Insights on Intake Frequencies, Dosages and Effects on Hematopoietic Stem Cell Populations in Cord Blood From a Longitudinal Prospective Pregnancy Cohort

Background

Paracetamol is the first choice for antipyretic or analgesic treatment throughout pregnancy. Products with Paracetamol are readily available over the counter and therefore easily accessible for self-medication. Epidemiological data on Paracetamol intake pattern during pregnancy and its potential immunological effects are sparse. We aimed to analyze a possible association between Paracetamol medication and numbers of hematopoietic stem cells (HSC) in cord blood.

Methods

The objective was addressed in the PRINCE (PRENATAL DETERMINANTS OF CHILDREN'S HEALTH) study, a population-based prospective pregnancy cohort study initiated in 2011 at the University Medical Center in Hamburg, Germany. 518 healthy pregnant women with singleton pregnancies were recruited during the first trimester. Three examinations were scheduled at the end of the 1st (gestational week 12–14), the 2nd (gestational week 22–24) and the 3rd trimester (gestational week 34–36). For 146 of these women, cord blood flow cytometry data were available. Paracetamol intake was assessed for each trimester of pregnancy.

Findings

Among the 518 enrolled women, 40% took Paracetamol as main analgesic treatment during pregnancy. The intake frequency and dosage of Paracetamol varied between the women and was overall low with a tendency towards higher frequencies and higher dosages in the third trimester. Paracetamol intake, particularly during the third trimester, resulted in decreased relative numbers of HSCs in cord blood, independent of maternal age, first-trimester BMI, parity, gestational age and birth weight (− 0.286 (95% CI − 0.592, 0.021), p = 0.068).

Interpretation

Prenatal Paracetamol intake, especially during the third trimester, may be causally involved in decreasing HSCs in cord blood.

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Paracetamol is the main analgesic agent used during pregnancy.

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Maternal Paracetamol intake was negatively associated with hematopoietic stem cell frequencies in cord blood.

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The third trimester seems to be most susceptible for Paracetamol induced reduction of the immune cell progenitors.

Our study focuses on the impact of Paracetamol intake during pregnancy on the offspring's immune development. We were able to show that maternal Paracetamol intake, particularly in the third trimester of pregnancy, was negatively associated with hematopoietic stem cell frequencies in cord blood. These results provide a potential missing link for an association between prenatal Paracetamol medication and childhood disease, particularly asthma, by adding a possible immunological pathway. While we fully acknowledge the medical need of analgesics in pregnancy to prevent or treat more harmful events, our data are valuable for clinical recommendations on self-medication with the OTC drug Paracetamol.

Voluntary intake of paracetamol-enriched drinking water and its influence on the success of embryo transfer in mice

Embryo transfer (ET) in mice is a key technique in biomedical research, and is carried out mostly via surgery by transferring founder embryos into pseudo-pregnant recipient females. To cover post-operative analgesic requirements in surrogate mothers, oral self-administration of painkillers has several advantages, but its effectiveness has also been criticized as voluntary ingestion of the drug can be uncertain. Additionally, concerns about potential negative side effects of analgesics on embryo viability and development have been raised. In this regard, we investigated the impact of orally administered analgesia by comparing the outcome of ET with and without paracetamol in the drinking water (3.5mg/ml) of surrogate mothers. Water intake increased significantly when paracetamol, as a sweet-tasting formulation (children's syrup), was added to the drinking water. Measurements of paracetamol concentrations in blood serum confirmed reasonable drug uptake. Success rate of ETs and the body weight of newborn offspring were not different whether paracetamol was administered for two days after surgery or not. In conclusion, paracetamol in drinking water was consumed voluntarily in substantial doses, without detectable side-effects, by freshly operated surrogate mothers, and can therefore be recommended as a feasible method for providing analgesic treatment for surgical ET in mice.

The association between paracetamol and asthma is still under debate

OBJECTIVE

To analyse the relationship between paracetamol and asthma.

DATA SOURCES

An English literature search using electronic search engines (PubMed and EMBASE) was conducted.

STUDY SELECTIONS

Articles published in peer-review journals, from 1990 to December 2015 were included. To perform the search for the most suitable and representative articles, keywords were selected ("asthma," "paracetamol" and "acetaminophen"). The evidence level was rated according to the criteria of the Oxford Centre For Evidence-Based Medicine.

RESULTS

The exposure to paracetamol during pregnancy was analysed in several cohort studies, showing an association between the prenatal exposure to paracetamol with suffering from asthma or presence of wheezing in childhood, especially for persistent wheezing. Nevertheless, a recent study concluded that the relationship between asthma and paracetamol is explained, at least in part, by confounding factors. Several works have also associated the exposure to paracetamol in the first years of life or in adults with the development of childhood asthma. Several pathophysiological mechanisms are known that could explain this relationship, such as the glutathione pathway, the decrease in the release of Th1 cytokines that are normally produced during febrile episodes, which would then lead to a predominance of Th2 cytokines, the cytotoxic effect of paracetamol for pneumocytes, a modulator effect on the activity of myeloperoxidase, as well as the possible antigenic effect of paracetamol, mediated by IgE.

CONCLUSIONS

There are many arguments that suggest a relationship between the use of paracetamol with the appearance of asthmatic symptoms, however the evidence is inconclusive.

Immunology of hepatic diseases during pregnancy

The mother's immune system has to adapt to pregnancy accepting the semi-allograft fetus and preventing harmful effects to the developing child. Aberrations in feto-maternal immune adaptation may result in disease of the mother, such as liver injury. Five pregnancy-associated liver disorders have been described so far, however, little is known concerning immune alterations promoting the respective disease. These liver disorders are pre-eclampsia, hemolysis, elevated liver enzymes, low platelet count (HELLP), acute fatty liver, hyperemesis gravidarum, and intrahepatic cholestasis of pregnancy. On the other hand, pre-existing autoimmune liver injury of the mother can be affected by pregnancy. This review intends to summarize current knowledge linking feto-maternal immunology and liver inflammation with a special emphasis on novel potential biomarkers.

Prenatal acetaminophen affects maternal immune and endocrine adaptation to pregnancy, induces placental damage, and impairs fetal development in mice

Acetaminophen (APAP; ie, Paracetamol or Tylenol) is generally self-medicated to treat fever or pain and recommended to pregnant women by their physicians. Recent epidemiological studies reveal an association between prenatal APAP use and an increased risk for asthma. Our aim was to identify the effects of APAP in pregnancy using a mouse model. Allogeneically mated C57Bl/6J females were injected i.p. with 50 or 250 mg/kg APAP or phosphate-buffered saline on gestation day 12.5; nonpregnant females served as controls. Tissue samples were obtained 1 or 4 days after injection. APAP-induced liver toxicity was mirrored by significantly increased plasma alanine aminotransferase levels. In uterus-draining lymph nodes of pregnant dams, the frequencies of mature dendritic cells and regulatory T cells significantly increased on 250 mg/kg APAP. Plasma progesterone levels significantly decreased in dams injected with APAP, accompanied by a morphologically altered placenta. Although overall litter sizes and number of fetal loss remained unaltered, a reduced fetal weight and a lower frequency of hematopoietic stem cells in the fetal liver were observed on APAP treatment. Our data provide strong evidence that prenatal APAP interferes with maternal immune and endocrine adaptation to pregnancy, affects placental function, and impairs fetal maturation and immune development. The latter may have long-lasting consequences on children's immunity and account for the increased risk for asthma observed in humans.