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We previously demonstrated that endogenous phosphatidic acid (PA) promotes liver regeneration after acetaminophen (APAP) hepatotoxicity. Here, we hypothesized that exogenous PA is also beneficial. To test that, we treated mice with a toxic APAP dose at 0 h, followed by PA or vehicle (Veh) post-treatment. We then collected blood and liver at 6, 24, and 52 h. Post-treatment with PA 2 h after APAP protected against liver injury at 6 h, and the combination of PA and N -acetyl-l-cysteine (NAC) reduced injury more than NAC alone. Interestingly, PA did not affect canonical mechanisms of APAP toxicity. Instead, transcriptomics revealed that PA activated interleukin-6 (IL-6) signaling in the liver. Consistent with that, serum IL-6 and hepatic signal transducer and activator of transcription 3 (Stat3) phosphorylation increased in PA-treated mice. Furthermore, PA failed to protect against APAP in IL-6-deficient animals. Interestingly, IL-6 expression increased 18-fold in adipose tissue after PA, indicating that adipose is a source of PA-induced circulating IL-6. Surprisingly, however, exogenous PA did not alter regeneration, despite the importance of endogenous PA in liver repair, possibly due to its short half-life. These data demonstrate that exogenous PA is also beneficial in APAP toxicity and reinforce the protective effects of IL-6 in this model., (© 2021 Chinese Pharmaceutical Association and Institute of Materia Medica, Chinese Academy of Medical Sciences. Production and hosting by Elsevier B.V.)

Background and Aim: Acetaminophen (APAP) overdose is a major cause of acute liver injury, but the role of macrophages in propagation of the hepatotoxicity is controversial. Early research revealed that macrophage inhibitors protect against APAP injury. However, later work demonstrated that macrophage ablation by acute pre-treatment with liposomal clodronate (LC) exacerbates the toxicity. To our surprise, during other studies, we observed that pre-treatment twice with LC seemed to protect against APAP hepatotoxicity, in contrast to acute pre-treatment. The aim of this study was to confirm that observation and to explore the mechanisms., Methods: We treated mice with empty liposomes (LE) or LC twice per week for 1 week before APAP overdose and collected blood and liver tissue at 0, 2, and 6 h post-APAP. We then measured liver injury (serum ALT activity, histology), APAP bioactivation (total glutathione, APAP-protein adducts), oxidative stress (oxidized glutathione [GSSG]), glutamate cysteine-ligase subunit c ( Gclc ) mRNA, and nuclear factor erythroid 2-related factor (Nrf2) immunofluorescence. We also confirmed ablation of macrophages by F4/80 immunohistochemistry., Results: Pre-treatment twice with LC dramatically reduced F4/80 staining, protected against liver injury, and reduced oxidative stress at 6 h post-APAP, without affecting APAP bioactivation. Importantly, Gclc mRNA was higher in the LC group at 0 h and total glutathione was higher at 2 h, indicating accelerated glutathione re-synthesis after APAP overdose due to greater basal glutamate-cysteine ligase. Oxidative stress was lower in the LC groups at both time points. Finally, total Nrf2 immunofluorescence was higher in the LC group., Conclusions: We conclude that multiple pre-treatments with LC protect against APAP by accelerating glutathione re-synthesis through glutamate-cysteine ligase. Investigators using two or possibly more LC pre-treatments to deplete macrophages, including peritoneal macrophages, should be aware of this possible confounder.

The standard circulating biomarker of liver injury in both clinical settings and drug safety testing is alanine aminotransferase (ALT). However, ALT elevations sometimes lack specificity for tissue damage. To identify novel serum biomarkers with greater specificity for injury, we combined unique animal models with untargeted proteomics, followed by confirmation with immunoblotting. Using proteomics, we identified 109 proteins in serum from mice with acetaminophen (APAP)-induced liver injury that were not detectable in serum from mice with benign ALT elevations due to high-dose dexamethasone (Dex). We selected 4 (alcohol dehydrogenase 1A1 [Aldh1a1], aldehyde dehydrogenase 1 [Adh1], argininosuccinate synthetase 1 [Ass1], and adenosylhomocysteinase [Ahcy]) with high levels for further evaluation. Importantly, all 4 were specific for injury when using immunoblots to compare serum from Dex-treated mice and mice with similar lower ALT elevations due to milder models of APAP or bromobenzene-induced liver injury. Immunoblotting for ALDH1A1, ADH1, and ASS1 in serum from APAP overdose patients without liver injury and APAP overdose patients with mild liver injury revealed that these candidate biomarkers can be detected in humans with moderate liver injury as well. Interestingly, further experiments with serum from rats with bile duct ligation-induced liver disease indicated that Aldh1a1 and Adh1 are not detectable in serum in cholestasis and may therefore be specific for hepatocellular injury and possibly even drug-induced liver injury, in particular. Overall, our results strongly indicate that ALDH1A1, ADH1, and ASS1 are promising specific biomarkers for liver injury. Adoption of these biomarkers could improve preapproval drug safety assessment., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Inner ear drug delivery is a major area of research and development, but relatively little is known about basic drug metabolism in the cochlea. Additionally, the use of potentially ototoxic drugs such as NSAIDs, chemotherapeutics and aminoglycosides is common, but little is known about the role of metabolism in ototoxicity of those drugs. To address those issues, we compared expression of major Cytochromes P450 (Cyps), UDP-glucuronosyl-transferases (Ugts), sulfotransferases (Sults), and drug transporters between cochleae and liver, an organ with high expression, in mice using qPCR and enzyme kinetics. Together, the tested drug-metabolizing enzymes (DMEs) and transporters account for metabolism of approximately 70-80% of all medically important drugs in the body. Expression of most Cyps was low in the cochlea compared to liver, but three displayed similar expression levels to the liver, and one (Cyp2c65) had significantly higher levels of expression in the cochlea (1.9 ± 0.06 fold vs. liver). Enzyme kinetics revealed undetectable levels of p450 activity in the cochlea, especially as compared to the liver. Similar results were obtained for expression of Ugts and Sults. Interestingly, expression of most transporters was also low, with one major exception: Mdr1/P-glycoprotein (P-gp), which is generally thought to be highly expressed in liver and poorly expressed in most of the nervous system, was 3-fold greater in cochlea. Importantly, P-gp is known to protect other tissues from toxicity of cancer drugs by acting as an efflux pump. Our data demonstrate overall low levels of expression of DMEs and transporters in the cochlea, and identify a few that may be important to consider when designing and testing drugs for local delivery to the inner ear., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Introduction: Public awareness of electronic nicotine delivery systems (ENDS) has increased over time, and the perception that ENDS offer a safer alternative to cigarettes may lead some pregnant women to use them to reduce cigarette smoking during pregnancy. No previous studies have used metabolite levels in hair to measure nicotine exposure for ENDS users during pregnancy. We aimed to measure and compare levels of nicotine, cotinine, and tobacco-specific nitrosamines (TSNAs) in hair samples from pregnant women who were current ENDS users, current smokers, and current non-smokers. We also aimed to estimate the association between ENDS use/smoking and smallness for gestational age (SGA)., Methods: We used hair specimens from pregnant women who were dual users (ENDS and cigarettes), smokers, and non-smokers from a prospective cohort study to estimate exposure to nicotine, cotinine, and TSNAs. The exposure biomarkers and self-reports of smoking and ENDS use were used in log-binomial regression models to estimate risk ratios (RRs) for SGA among offspring., Results: Nicotine concentrations for pregnant dual users were not significantly different from those for smokers (11.0 and 10.6 ng/mg hair, respectively; p=0.58). Similarly, levels of cotinine, and TSNAs for pregnant dual users were not lower than those for smokers. The RR for SGA was similar for dual users and smokers relative to nonsmokers, (RR=3.5, 95% CI: 0.8-14.8) and (RR=3.3, 95% CI: 0.9-11.6), respectively. Using self-reports confirmed by hair nicotine, the RR values for dual ENDS users and smokers were 8.3 (95% CI: 1.0-69.1) and 7.3 (95% CI:1.0-59.0), respectively., Conclusions: We did not observe lower levels of nicotine, cotinine, and TSNAs for current dual users compared to smokers during pregnancy. The risk of SGA for offspring of pregnant dual users was similar to that for offspring of pregnant smokers. Future studies are needed to further estimate the magnitude of the association between ENDS use and smallness for gestational age., Competing Interests: The authors declare that they have no competing interests, financial or otherwise, related to the current work. U. Ekanem reports grants from Arkansas Department of Health, personal fees from University of Arkansas for Medical Sciences Fay W. Boozman College of Public Health, grants from National Institutes of Health (NIH) - National Center for Research Resources and National Center for Advancing Translational Sciences, during the conduct of the study. The rest of the authors have also completed and submitted an ICMJE form for disclosure of potential conflicts of interest.

Introduction: The 2016 US Surgeon General's Report suggests that the use of electronic nicotine delivery systems (ENDS) is a fetal risk factor. However, no previous study has estimated their effect on adverse pregnancy outcomes. We assessed the prevalence of current ENDS use in pregnant women and explored the effect on birth weight and smallness-for-gestational-age (SGA), correcting for misclassification from nondisclosure of smoking status., Methods: We conducted a cohort study with 248 pregnant women using questionnaire data and biomarkers (salivary cotinine, exhaled carbon monoxide, and hair nicotine). We evaluated the association between birth weight and the risk of SGA by applying multivariate linear and log-binomial regression to reproductive outcome data for 232 participants. Participants who did not disclose their smoking status were excluded from the referent group. Sensitivity analysis corrected for misclassification of smoking/ENDS use status., Results: The prevalence of current ENDS use among pregnant women was 6.8% (95% CI: 4.4-10.2%); most of these (75%) were concurrent smokers. Using self-reports, the estimated risk ratio of SGA for ENDS users was nearly two times the risk in the unexposed (RR=1.9, 95% CI: 0.6-5.5), and over three times that for ENDS-only users versus the unexposed (RR=3.1, 95% CI: 0.8-11.7). Excluding from the referent group smokers who did not disclose their smoking status, the risk of SGA for ENDS-only use was 5 times the risk in the unexposed (RR=5.1, 95% CI: 1.1- 22.2), and almost four times for all types of ENDS users (RR=3.8, 95% CI: 1.3-11.2). SGA risk ratios for ENDS users, corrected for misclassification due to self-report, were 6.5-8.5 times that of the unexposed., Conclusions: Our data suggest that ENDS use is associated with an increased risk of SGA., Competing Interests: Authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none was reported.

Repair mechanisms after acetaminophen (APAP) hepatotoxicity are poorly understood. We recently discovered that phosphatidic acid (PA) increases in mice and humans after APAP overdose, and is critical for liver regeneration. Here, we hypothesized that PA inhibits glycogen synthase kinase-3β (GSK3β), a component of canonical Wnt/β-catenin signaling, after APAP overdose. To test that, we treated mice with 300 mg/kg APAP at 0 h followed by vehicle or 20 mg/kg of the glycerol 3-phosphate acyltransferase inhibitor FSG67 at 3, 24 and 48 h. Some mice also received the GSK3 inhibitor L803-mts. Blood and liver were collected at multiple time points. Consistent with our earlier results, FSG67 did not affect toxicity (ALT, histology), APAP bioactivation (total glutathione), or oxidative stress (oxidized glutathione), but did reduce expression of proliferating cell nuclear antigen (PCNA) at 52 h. We then measured GSK3β phosphorylation and found it was dramatically decreased by FSG67 at 24 h, before PCNA dropped. Expression of cyclin D1, downstream of Wnt/β-catenin, was also reduced. To determine if the effect of FSG67 on GSK3β is important, we treated mice with FSG67 and L803-mts after APAP. Importantly, L803-mts rescued hepatocyte proliferation and survival. Our data indicate PA and lysoPA may support recovery after APAP overdose by inhibiting GSK3β., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Liver, the major metabolic organ in the body, is known for its remarkable capacity to regenerate. Whereas partial hepatectomy (PHx) is a popular model for the study of liver regeneration, the liver also regenerates after acute injury, but less is known about the mechanisms that drive it. Recent studies have shown that liver regeneration is critical for survival in acute liver failure (ALF), which is usually due to drug-induced liver injury (DILI). It is sometimes assumed that the signaling pathways involved are similar to those that regulate regeneration after PHx, but there are likely to be critical differences. A better understanding of regeneration mechanisms after DILI and hepatotoxicity in general could lead to development of new therapies for ALF patients and new biomarkers to predict patient outcome. Here, we summarize what is known about the mechanisms of liver regeneration and repair after hepatotoxicity. We also review the literature in the emerging field of liver regeneration biomarkers., (© 2019 Elsevier Inc. All rights reserved.)

This study applied a text string search algorithm to ascertain suspect farm tractor or agricultural machinery-related injuries in data sources available for 2000-2014 in the state of Arkansas. The occurrences of tractor or other agricultural machinery-related injuries were compared with data available from the Centers for Disease Control and Prevention's National Center for Health Statistics (NCHS) and the Bureau of Labor Statistics' Census of Fatal Occupational Injuries (CFOI). For death certificates that assigned an external cause of death, the authors first collected all those that were coded as related to agricultural machinery, based on search strings for occupation and industry and a description of how the injury occurred. They then inspected each case individually and removed those that were likely unrelated to agricultural machinery. This approach significantly increased (by 7.8 times) the number of suspect agricultural machinery-related fatalities compared to the number reported to CFOI, but there was only a 17% (not statistically significant) increase compared to NCHS. All hospital records with any discharge diagnosis coded as related to agricultural machinery were selected. Descriptive analysis of the fatalities and hospital records showed a significantly increased risk among men above retirement age, peaks during the summer, and an increased risk in the Mississippi delta region. About one-third of the agricultural machinery-related fatalities were due to overturns. The use of the algorithm can improve ascertainment of fatal agricultural machinery-related injuries in Arkansas. The death records were found to be rich in data on the circumstances of the injuries, which can be used to screen for tractor-related fatalities and, if confirmed, translated into action to improve the safety of Arkansas farmers.

Coffin-Siris syndrome is a multiple anomaly/mental retardation syndrome characterized by "coarse" facial appearance, hypoplastic or absent nails on the fifth digits, generalized hirsutism with sparse scalp hair, hypotonia, and developmental delay. Due to several reports of affected sibs with or without a mildly affected parent, both autosomal recessive and autosomal dominant inheritance have been suggested. All previous patients with well-documented Coffin-Siris syndrome are chromosomally normal, and the gene has not been mapped. We report on an infant with typical findings of Coffin-Siris syndrome who also has a de novo apparently balanced translocation of chromosomes 1 and 7, karyotype 46,XY,t(1;7)(q21.3;q34). The parental chromosomes are normal and none of the relatives have signs of Coffin-Siris syndrome. The breakpoints 1q21.3 and 7q34 are suggested as possible locations for a Coffin-Siris gene.

We report a new kindred containing 4 patients with X-linked alpha-thalassemia/mental retardation syndrome ((ATR-X). Like previously reported ATR-X patients, these children are all genetic males with severe developmental delay and characteristic facial appearance. The genital anomalies are more severe than in most previous cases and have led to a female sex of rearing for 3 of the 4 patients. The hematologic expression is extremely mild and was not demonstrable on routine hematologic studies including hemoglobin electrophoresis, but the three living patients all had hemoglobin H inclusions on brilliant cresyl blue stained peripheral smears. The combination of skewed X-inactivation and haplotype analysis at Xq12-q21.3 confirmed carrier status in the 3 obligate carriers in the kindred and led to identification of an additional carrier. Two other women in the kindred appear to be noncarriers on the basis of normal X-inactivation and/or inheritance of a different Xq12-21.3 haplotype. More widespread use of brilliant cresyl blue staining for HbH inclusions in individuals with the facial phenotype of ATR-X and/or ambiguous genitalia may lead to the identification of more affected patients and improved understanding of the clinical spectrum of ATR-X.