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Background: Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that persist in the environment and can accumulate in humans, leading to adverse health effects. MicroRNAs (miRNAs) are emerging biomarkers that can advance the understanding of the mechanisms of PFAS effects on human health. However, little is known about the associations between PFAS exposures and miRNA alterations in humans., Objective: To investigate associations between PFAS concentrations and miRNA levels in children., Methods: Data from two distinct cohorts were utilized: 176 participants (average age 17.1 years; 75.6% female) from the Teen-Longitudinal Assessment of Bariatric Surgery (Teen-LABS) cohort in the United States, and 64 participants (average age 6.5 years, 39.1% female) from the Rhea study, a mother-child cohort in Greece. PFAS concentrations and miRNA levels were assessed in plasma samples from both studies. Associations between individual PFAS and plasma miRNA levels were examined after adjusting for covariates. Additionally, the cumulative effects of PFAS mixtures were evaluated using an exposure burden score. Ingenuity Pathways Analysis was employed to identify potential disease functions of PFAS-associated miRNAs., Results: Plasma PFAS concentrations were associated with alterations in 475 miRNAs in the Teen-LABs study and 5 miRNAs in the Rhea study (FDR p < 0.1). Specifically, plasma PFAS concentrations were consistently associated with decreased levels of miR-148b-3p and miR-29a-3p in both cohorts. Pathway analysis indicated that PFAS-related miRNAs were linked to numerous chronic disease pathways, including cardiovascular diseases, inflammatory conditions, and carcinogenesis., Conclusion: Through miRNA screenings in two independent cohorts, this study identified both known and novel miRNAs associated with PFAS exposure in children. Pathway analysis revealed the involvement of these miRNAs in several cancer and inflammation-related pathways. Further studies are warranted to enhance our understanding of the relationships between PFAS exposure and disease risks, with miRNA emerging as potential biomarkers and/or mediators in these complex pathways., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Vaia Lida Chatzi reports financial support was provided by The National Institute of Environmental Health Sciences. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Hepatopulmonary syndrome (HPS) is associated with increased waitlist mortality in liver transplantation (LT) candidates. Children with HPS are granted Model for End-Stage Liver Disease (MELD)/Pediatric End-Stage Liver Disease (PELD) exception points for waitlist prioritization in the United States based on criterion developed for adults. In this study, the impact of this MELD/PELD exception policy on post-LT survival in children was examined. A retrospective cohort of patients aged younger than 18 years with a MELD/PELD exception request who underwent LT between 2007 and 2018 were identified in the Scientific Registry of Transplant Recipients. Patients were stratified by waitlist partial pressure of arterial oxygen (PaO 2 ) to assess risk factors for waitlist mortality and post-LT survival. Among 3082 pediatric LT recipients included in the study, 124 patients (4%) received MELD/PELD exception points for HPS. Patients with HPS were a median age of 9 years (interquartile range: 6, 12 years), 54.8% were girls, and 54% were White. Most patients (87.9%) were listed with laboratory MELD/PELD scores <15. Waitlist mortality for patients with HPS exception points was rare and not different from patients without HPS. When stratified by pre-LT PaO 2 , hypoxemia severity was not associated with differences in 1-, 3-, or 5-year survival rates after LT ( p = 0.13). However, patients with HPS showed a slightly lower survival rate at 5 years compared with patients without HPS (88.7% vs. 93.4%; p = 0.04). MELD/PELD exceptions for children with HPS mitigated waitlist mortality, and recipients with HPS experienced excellent 5-year survival after LT, although slightly lower than in patients without HPS. Unlike adults with HPS, the severity of pre-LT hypoxemia in children does not impact post-LT survival. These data suggest that adult criteria for granting MELD/PELD exception points may not appropriately capture HPS severity in pediatric patients. Further prospective multicenter studies to examine the risk factors predicting negative survival outcomes in children with HPS are warranted., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Experimental evidence indicates that exposure to certain pollutants is associated with liver damage. Per- and polyfluoroalkyl substances (PFAS) are persistent synthetic chemicals widely used in industry and consumer products and bioaccumulate in food webs and human tissues, such as the liver., Objective: The objective of this study was to conduct a systematic review of the literature and meta-analysis evaluating PFAS exposure and evidence of liver injury from rodent and epidemiological studies., Methods: PubMed and Embase were searched for all studies from earliest available indexing year through 1 December 2021 using keywords corresponding to PFAS exposure and liver injury. For data synthesis, results were limited to studies in humans and rodents assessing the following indicators of liver injury: serum alanine aminotransferase (ALT), nonalcoholic fatty liver disease, nonalcoholic steatohepatitis, or steatosis. For human studies, at least three observational studies per PFAS were used to conduct a weighted z -score meta-analysis to determine the direction and significance of associations. For rodent studies, data were synthesized to qualitatively summarize the direction and significance of effect., Results: Our search yielded 85 rodent studies and 24 epidemiological studies, primarily of people from the United States. Studies focused primarily on legacy PFAS: perfluorooctanoic acid (PFOA), perfluorooctanesulfonic acid (PFOS), perfluorononanoic acid (PFNA), and perfluorohexanesulfonic acid. Meta-analyses of human studies revealed that higher ALT levels were associated with exposure to PFOA ( z -score = 6.20, p < 0.001 ), PFOS ( z -score = 3.55, p < 0.001 ), and PFNA ( z -score = 2.27, p = 0.023 ). PFOA exposure was also associated with higher aspartate aminotransferase and gamma-glutamyl transferase levels in humans. In rodents, PFAS exposures consistently resulted in higher ALT levels and steatosis., Conclusion: There is consistent evidence for PFAS hepatotoxicity from rodent studies, supported by associations of PFAS and markers of liver function in observational human studies. This review identifies a need for additional research evaluating next-generation PFAS, mixtures, and early life exposures. https://doi.org/10.1289/EHP10092.

Background: Nonalcoholic fatty liver disease (NAFLD) is the most common form of chronic liver disease in children and can progress to liver cirrhosis during childhood. Patients with more advanced fibrosis on biopsy tend to have more liver complications. Noninvasive hepatic fibrosis scores have been developed for adult patients with NAFLD; however, these scores have not been validated in children. The aim of our study was to evaluate some of these scores in assessing the presence of fibrosis in children with biopsy-proven NAFLD., Methods: Our study consisted of 92 biopsy-proven NAFLD children from five major US centers. Fibrosis was determined by an experienced pathologist (F0-4). Clinically significant fibrosis was defined as fibrosis stage ≥ 2, and advanced fibrosis was defined as F3-4. The following fibrosis scores were calculated for each child: AST/ALT ratio, AST/platelet ratio index (APRI), NAFLD fibrosis score (NFS), and FIB-4 index. ROC was performed to assess the performance of different scores for prediction of presence of any, significant, or advanced fibrosis. A p value < 0.05 was considered statistically significant., Results: Mean age was 13.3 ± 3 years, and 33 % were females. Eleven (12 %) subjects had no fibrosis, 35 (38 %) had fibrosis score of 1, 26 (28 %) had fibrosis score of 2, and 20 (22 %) had a score of 3. APRI had a fair diagnostic accuracy for the presence of any fibrosis (AUC of 0.80) and poor diagnostic accuracy for significant or advanced fibrosis. AST/ALT, NFS, and FIB-4 index all either had poor diagnostic accuracy or failed to diagnose the presence of any, significant, or advanced fibrosis., Conclusion: Noninvasive hepatic fibrosis scores developed in adults had poor performance in diagnosing significant fibrosis in children with NAFLD. Our results highlight the urgent need to develop a reliable pediatric fibrosis score.

Objectives: Nonalcoholic fatty liver disease (NAFLD), the most common cause of liver disease among US children, may be associated with cardiovascular disease (CVD) risk. The present study sought to determine the prevalence of dyslipidemia in children with NAFLD and assess dyslipidemia by liver histology and histologic changes., Methods: Individuals in the Treatment of NAFLD in Children (TONIC) trial were included (N = 173). In the TONIC trial, children with NAFLD were randomized to vitamin E, metformin, or placebo for 96 weeks. Nonalcoholic steatohepatitis (NASH) improved in 56 children. Change in lipid levels from baseline and 96 weeks was compared between patients with and without histologic improvement and with and without NASH., Results: Dyslipidemia was frequent, with low high-density lipoprotein (HDL) (< 40 mg/dL) in 61.8%, hypertriglyceridemia (≥ 130 mg/dL) in 50.3%, hypercholesterolemia (≥ 200 mg/dL) in 23.7%, elevated low-density lipoprotein (LDL) (≥ 130 mg/dL) in 21.5%, elevated non-HDL cholesterol (non-HDL-C) (≥ 145 mg/dL) in 35.2%, and triglycerides/HDL > 3.0 in 57.2% of patients. Histologic improvement was associated with significant decreases in cholesterol (-11.4 mg/dL vs -1.9 mg/dL, P = 0.04), LDL (-11.2 mg/dL vs -2.1 mg/dL, P = 0.04), and non-HDL-C (-8.8 mg/dL vs 0.5 mg/dL, P = 0.03) compared with those without improvement. Children with NASH resolution had significant decreases in cholesterol (-10.0 mg/dL vs -0.9 mg/dL, P = 0.02) and non-HDL-C (-7.3 mg/dL vs 1.1 mg/dL, P = 0.01) compared with those without NASH resolution. There was no improvement in triglycerides, HDL level, or triglycerides/HDL ratio in either group., Conclusions: Dyslipidemia is frequent in children with NAFLD. NASH resolution and histologic improvement are associated with improvements in some forms of dyslipidemia.

Unlabelled: Nonalcoholic fatty liver disease (NAFLD) may have distinct histological features in children and adults, but to date limited data are available on the spectrum and significance of histological lesions in pediatric patients. We conducted a multicenter study of children with well-characterized, biopsy-proven NAFLD to (1) assess the presence and significance of a constellation of histological lesions and (2) identify clinical and laboratory predictors of disease severity. One hundred thirty children with NAFLD seen from 1995 to 2007 in five centers in the United States and Canada were studied. Clinical and laboratory data were collected. Slides stained with hematoxylin-eosin and trichrome were evaluated by two liver pathologists. The NAFLD activity score (NAS) and the pattern of liver injury (type 1 or adult versus type 2 or pediatric nonalcoholic steatohepatitis [NASH]) were recorded. Fibrosis was staged using a published 7-point scale. The median age was 12 years (range, 4-18 years); 63% were boys, and 52% were Caucasian. Fibrosis was present in 87% of patients; of these, stage 3 (bridging fibrosis) was present in 20%. No patient had cirrhosis. The median NAS was 4. Overlapping features of both type 1 (adult pattern) and type 2 (pediatric pattern) NASH were found in 82% of patients. Compared with patients with no or mild fibrosis, those with significant fibrosis were more likely to have higher lobular and portal inflammation scores (P < 0.01), perisinusoidal fibrosis (P < 0.001), and NAS > or =5 (P < 0.005). Serum aspartate aminotransferase levels were the only clinical or laboratory data that independently predicted severity of fibrosis (P = 0.003)., Conclusion: Our results highlight the limitations of published proposals to classify pediatric NAFLD, and identified histological lesions associated with progressive disease.