Effects of Preanalytical Sample Collection and Handling on Comprehensive Metabolite Measurements in Human Urine Biospecimens.

Epidemiology studies evaluate associations between the metabolome and disease risk. Urine is a common biospecimen used for such studies due to its wide availability and non-invasive collection. Evaluating the robustness of urinary metabolomic profiles under varying preanalytical conditions is thus of interest. Here we evaluate the impact of sample handling conditions on urine metabolome profiles relative to the gold standard condition (no preservative, no refrigeration storage, single freeze thaw). Conditions tested included the use of borate or chlorhexidine preservatives, various storage and freeze/thaw cycles. We demonstrate that sample handling conditions impact metabolite levels, with borate showing the largest impact with 125 of 1048 altered metabolites (adjusted P < 0.05). When simulating a case-control study with expected inconsistencies in sample handling, we predicted the occurrence of false positive altered metabolites to be low (< 11). Predicted false positives increased substantially (≥63) when cases were simulated to undergo alternate handling. Finally, we demonstrate that sample handling impacts on the urinary metabolome were markedly smaller than those in serum. While changes in urine metabolites incurred by sample handling are generally small, we recommend implementing consistent handling conditions and evaluating robustness of metabolite measurements for those showing significant associations with disease outcomes.

A preclinical model of severe NASH-like liver injury by chronic administration of a high-fat and high-sucrose diet in mice.

Non-alcoholic fatty liver disease (NAFLD) is a progressive liver disease, affecting 38% of adults globally. If left untreated, NAFLD may progress to more advanced forms of the disease, including non-alcoholic steatohepatitis (NASH), liver cirrhosis, and fibrosis. Early NAFLD detection is critical to prevent disease progression. Using an obesogenic high-fat and high-sucrose (HF/HS) diet, we characterized the progression of NAFLD in male and female Collaborative Cross CC042 mice after 20-, 40-, and 60-week intervals of chronic HF/HS diet feeding. The incidence and severity of liver steatosis, inflammation, and fibrosis increased in both sexes over time, with male mice progressing to a NASH-like disease state faster than female mice, as indicated by earlier and more pronounced changes in liver steatosis. Histopathological indication of macrovesicular steatosis and gene expression changes of key lipid metabolism genes were found to be elevated in both sexes after 20 weeks of HF/HS diet. Measurement of circulating markers of inflammation (CXCL10 and TNF-α), histopathological analysis of immune cell infiltrates, and gene expression changes in inflammation-related genes indicated significant liver inflammation after 40 and 60 weeks of HF/HS diet exposure in both sexes. Liver fibrosis, as assessed by Picosirius red and Masson's trichrome staining and changes in expression of key fibrosis related genes indicated significant changes after 40 and 60 weeks of HF/HS diet exposure. In conclusion, we present a preclinical animal model of dietary NAFLD progression, which recapitulates human pathophysiological and pathomorphological changes, that could be used to better understand the progression of NAFLD and support development of new therapeutics.

An evaluation of the National Institutes of Health grants portfolio: identifying opportunities and challenges for multi-omics research that leverage metabolomics data.

BACKGROUND: Through the systematic large-scale profiling of metabolites, metabolomics provides a tool for biomarker discovery and improving disease monitoring, diagnosis, prognosis, and treatment response, as well as for delineating disease mechanisms and etiology. As a downstream product of the genome and epigenome, transcriptome, and proteome activity, the metabolome can be considered as being the most proximal correlate to the phenotype. Integration of metabolomics data with other -omics data in multi-omics analyses has the potential to advance understanding of human disease development and treatment. AIM OF REVIEW: To understand the current funding and potential research opportunities for when metabolomics is used in human multi-omics studies, we cross-sectionally evaluated National Institutes of Health (NIH)-funded grants to examine the use of metabolomics data when collected with at least one other -omics data type. First, we aimed to determine what types of multi-omics studies included metabolomics data collection. Then, we looked at those multi-omics studies to examine how often grants employed an integrative analysis approach using metabolomics data. KEY SCIENTIFIC CONCEPTS OF REVIEW: We observed that the majority of NIH-funded multi-omics studies that include metabolomics data performed integration, but to a limited extent, with integration primarily incorporating only one other -omics data type. Some opportunities to improve data integration may include increasing confidence in metabolite identification, as well as addressing variability between -omics approach requirements and -omics data incompatibility.

Pedagogic Tailoring of a Human Research Ethics Training for Community-Engaged Research With Latinos.

Because of the increase in community-engaged research, several human research ethics trainings for laypeople have been developed. We aim to (1) describe the pedagogical tailoring of a research ethics training for laypeople for a research study where promotores-community health workers-delivered an intervention to increase health care access and promote healthy behaviors among Latinos and (2) present results of the application of the training after 4 months in the field. We tailored a previously developed training to Latino community members implementing a research study. Key modifications included (1) translation (2) use of pedagogical tools, such as cooperative learning, role-plays, and inclusion of cultural preferences. One novel addition was to use dialogues that the trainees enacted and then discussed. We evaluated the training with a posttraining survey with eight community liaisons and 13 promotores implementing the intervention, and a focus group with eight promotores, 4 months after working in the field. Trainees said they felt confident obtaining informed consent, felt the dialogues were realistic and helped them remember what they learned, and wanted more feedback from trainers on their performance. Promotores demonstrated the application of ethical principles beyond the training by discussing the possibility of advertising broadly in social media (justice), the risks and benefits of providing community resources to participants (beneficence), and the university's role in legitimizing their position as promotores (respect). We conclude that a pedagogically tailored ethics research training for laypeople can be successful and that dialogues to be enacted need to be explored further.

Preanalytical Sample Handling Conditions and Their Effects on the Human Serum Metabolome in Epidemiologic Studies.

Many epidemiologic studies use metabolomics for discovery-based research. The degree to which sample handling may influence findings, however, is poorly understood. In 2016, serum samples from 13 volunteers from the US Department of Agriculture's Beltsville Human Nutrition Research Center were subjected to different clotting (30 minutes/120 minutes) and refrigeration (0 minutes/24 hours) conditions, as well as different numbers (0/1/4) and temperatures (ice/refrigerator/room temperature) of thaws. The median absolute percent difference (APD) between metabolite levels and correlations between levels across conditions were estimated for 628 metabolites. The potential for handling artifacts to induce false-positive associations was estimated using variable hypothetical scenarios in which 1%-100% of case samples had different handling than control samples. All handling conditions influenced metabolite levels. Across metabolites, the median APD when extending clotting time was 9.08%. When increasing the number of thaws from 0 to 4, the median APD was 10.05% for ice and 5.54% for room temperature. Metabolite levels were correlated highly across conditions (all r's ≥ 0.84), indicating that relative ranks were preserved. However, if handling varied even modestly by case status, our hypotheticals showed that results can be biased and can result in false-positive findings. Sample handling affects levels of metabolites, and special care should be taken to minimize effects. Shorter room-temperature thaws should be preferred over longer ice thaws, and handling should be meticulously matched by case status.

Characterization of the variability in the extent of nonalcoholic fatty liver induced by a high-fat diet in the genetically diverse Collaborative Cross mouse model.

Interindividual variability and sexual dimorphisms in the development of nonalcoholic fatty liver disease (NAFLD) are still poorly understood. In the present study, male and female strains of Collaborative Cross (CC) mice were fed a high-fat and high-sucrose (HF/HS) diet or a control diet for 12 weeks to investigate interindividual- and sex-specific variations in the development of NAFLD. The severity of liver steatosis varied between sexes and individual strains and was accompanied by an elevation of serum markers of insulin resistance, including increases in total cholesterol, low-density lipoproteins, high-density lipoproteins, phospholipids, and glucose. The development of NAFLD was associated with overexpression of the critical fatty acid uptake and de novo lipogenesis genes Pparg, Mogat1, Cd36, Acaab1, Fabp2, and Gdf15 in male and female mice. The expression of Pparg, Mogat1, and Cd36 was positively correlated with liver triglycerides in male mice, and Mogat1 and Cd36 expression were positively correlated with liver triglycerides in female mice. Our results indicate the value of CC mice in combination with HF/HS diet-induced alterations as an approach to study the susceptibility and interindividual variabilities in the pathogenesis of nonalcoholic fatty liver and early nonalcoholic steatohepatitis at the population level, uncovering of susceptible and resistant cohorts, and identifying sex-specific molecular determinants of disease susceptibility.

Generational Status, Language Use, Parental Limit Setting, and Screen Time in US Latinx Children.

Latinx children engage in excessive screen time and are disproportionately affected by obesity. We examined the effect of generational status and language use on screen time in 6- to 11-year-old Latinx children and whether parental limit setting mediated that relationship. Participants included 3127 children (aged 9.2 ± 2.0 years; 54% male) from the 2011-2012 National Survey of Children's Health. Spanish language use was associated with 14.0 more minutes per day of screen time (P = .038); parental limit setting partially mediated this relationship (11.4%). Future research should explore the protective role of parental limit setting in reducing screen time in Latinx children.

Implementation Monitoring of a Promotora-Led, Home-Based Obesity Prevention Pilot Study With Latino Preschool Children and Their Mothers.

BACKGROUND: Latino preschool children have higher rates of obesity than children from other racial/ethnic backgrounds. Few effective, culturally-tailored obesity prevention interventions exist that have focused on Latino preschool children, and even fewer have published results of the process evaluation. The purpose of this paper was to monitor reach, fidelity, and completeness of implementation to determine whether ANDALE, a promising promotora-led, home-based pilot study to prevent obesity in Latino preschool children, was implemented as planned. METHODS: Guided by a logic model, we assessed reach, implementation fidelity and completeness through descriptive analyses of multiple data sources. Reach was assessed through attendance records. Fidelity was assessed via observation checklist and completeness was assessed via survey with both parents and promotoras in a subsample of 12 families. RESULTS: Promotoras recruited participants primarily through their own social networks and delivered the intervention to 50 families (mother-child dyads); the majority were of Mexican-origin, low-acculturation, dual-parent households. Nearly all (98%) families completed the whole 10-week intervention. Results demonstrated completeness and fidelity of implementation were acceptable in a subsample of 12 families. In sum, 75% of families in the subsample met the criteria (≥75%) for overall implementation of essential program elements (i.e., reach, completeness, and fidelity). CONCLUSION: Evidence suggests that ANDALE was delivered with high levels of completeness and fidelity in this sample of Latino families with preschool-aged children. These results support implementation of ANDALE in a large, randomized trial.

Absorption and metabolism of isothiocyanates formed from broccoli glucosinolates: effects of BMI and daily consumption in a randomised clinical trial.

Sulphoraphane originates from glucoraphanin in broccoli and is associated with anti-cancer effects. A preclinical study suggested that daily consumption of broccoli may increase the production of sulphoraphane and sulphoraphane metabolites available for absorption. The objective of this study was to determine whether daily broccoli consumption alters the absorption and metabolism of isothiocyanates derived from broccoli glucosinolates. We conducted a randomised cross-over human study (n 18) balanced for BMI and glutathione S-transferase µ 1 (GSTM1) genotype in which subjects consumed a control diet with no broccoli (NB) for 16 d or the same diet with 200 g of cooked broccoli and 20 g of raw daikon radish daily for 15 d (daily broccoli, DB) and 100 g of broccoli and 10 g of daikon radish on day 16. On day 17, all subjects consumed a meal of 200 g of broccoli and 20 g of daikon radish. Plasma and urine were collected for 24 h and analysed for sulphoraphane and metabolites of sulphoraphane and erucin by triple quadrupole tandem MS. For subjects with BMI >26 kg/m2 (median), plasma AUC and urinary excretion rates of total metabolites were higher on the NB diet than on the DB diet, whereas for subjects with BMI <26 kg/m2, plasma AUC and urinary excretion rates were higher on the DB diet than on the NB diet. Daily consumption of broccoli interacted with BMI but not GSTM1 genotype to affect plasma concentrations and urinary excretion of glucosinolate-derived compounds believed to confer protection against cancer. This trial was registered as NCT02346812.

ANDALE Pittsburgh: results of a promotora-led, home-based intervention to promote a healthy weight in Latino preschool children.

BACKGROUND: Latino preschool children have higher rates of obesity than preschool children from other racial/ethnic groups; however, few effective, culturally appropriate interventions exist targeting this group. The purpose of this study was to test the feasibility of a 10-week, promotora-mediated, home-based intervention to promote a healthy weight in Latino preschool children. METHODS: Trained promotoras (community health workers) delivered 10, 90-min weekly interactive and tailored sessions to Latino families living in Allegheny County. Participants were recruited through promotoras' own social networks and community gatherings, flyers, and word of mouth. Primary outcome measures included child body mass index (BMI) z-score and percentile. Secondary outcome measures included child objectively measured physical activity and dietary intake, and the home social and physical environment (e.g., parent health behaviors, parent self-efficacy, parental support, physical activity equipment in the home). The final analysis sample included 49 of 51 participants who completed both baseline and follow-up assessments. RESULTS: Participants included mothers (33.5 ± 6.1 years old) and their preschool-aged children who were primarily 1st generation immigrants from Mexico (65%). The primary analyses of BMI percentile and z-score showed no change post-intervention. However, there was a significant decrease in child BMI percentile for overweight and obese children from baseline to follow-up (p < .05). We also saw significant pre/post increases in child daily fruit and vegetable intake, and parent moderate-to-vigorous physical activity, fruit and vegetable servings per day, and self-efficacy; and significant decreases in child saturated fat and added-sugar intake, and child and parent screen time (p's < .05). CONCLUSIONS: Despite the short duration of the intervention and follow-up, this pilot study showed promising effects of a promotora-mediated intervention to promote a healthy weight in Latino preschool children.

Validation of the QOLIBRI - Quality of Life after Brain Injury questionnaire in patients after TBI in Israel.

BACKGROUND: The QOLIBRI - Quality of Life after Brain Injury questionnaire was developed by the QOLIBRI Task Force (QTF). Our goal was to investigate the applicability, validity and reliability of the QOLIBRI in Israel. METHODS: Validation of the Hebrew questionnaire was performed after it had been administered to 128 adults with traumatic brain injury (TBI), who were between 3 months' and 15 years' post-discharge from rehabilitation. RESULTS: The internal consistency of the QOLIBRI subscales with the QOLIBRI Total scale was high (Cronbach's α = 0.92); the same was true regarding the correlations between each QOLIBRI subscale and its own items (α = 0.92-0.95). Significant and high Pearson's and Spearman's correlations of the QOLIBRI subscales with demographic and clinical characteristics of the GOSE, ADL, HADS, SF-36, and various aspects of self-reported health status were found. Factor analyses (FA) were applied to confirm the validity of the Hebrew version, using the maximum likelihood method. The six subscales explained 100% of the variance. CONCLUSION: The Hebrew version of the QOLIBRI was found to be useful, meaningful and meeting psychometric criteria in persons after TBI in Israel. The findings support the cross-cultural applicability of the QOLIBRI, regardless of cultural and social differences.

Status of hepatic DNA methylome predetermines and modulates the severity of non-alcoholic fatty liver injury in mice.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a major health problem and a leading cause of chronic liver disease in the United States and Western countries. In humans, genetic factors greatly influence individual susceptibility to NAFLD; nonetheless, the effect of inter-individual differences in the normal liver epigenome with regard to the susceptibility to NAFLD has not been determined. RESULTS: In the present study, we investigated the association between the DNA methylation status in the livers of A/J and WSB/EiJ mice and the severity of NAFLD-associated liver injury. We demonstrate that A/J and WSB/EiJ mice, which are characterized by significant differences in the severity of liver injury induced by a choline- and folate-deficient (CFD) diet exhibit substantial differences in cytosine DNA methylation in their normal livers. Furthermore, feeding A/J and WSB/EiJ mice a CFD diet for 12 weeks resulted in different trends and changes in hepatic cytosine DNA methylation. CONCLUSION: Our findings indicate a primary role of hepatic DNA methylation in the pathogenesis of NAFLD and suggest that individual variations in DNA methylation across the genome may be a factor determining and influencing the vulnerability to NAFLD.

What is really causing the obesity epidemic? A review of reviews in children and adults.

Obesity prevention is a public health priority and intervention strategies have focused primarily on healthy eating and physical activity in children and adults. To date, no review has systematically compiled and synthesised the scientific evidence from published review articles to determine whether there is clear consensus on the causes of obesity. A systematic review of the literature was conducted searching PubMed/Medline for narrative and systematic review articles published between January 1990 and October 2014 that examined the causes of obesity. In total, 12 of 65 articles met the inclusion criteria; 7 reviews focused on adults (1 systematic, 6 narrative) and 5 reviews on children (2 systematic, 3 narrative). The most popular cause of obesity identified in reviews of adult studies was "combined physical activity and diet" (3 of 7 studies), whereas the most popular cause specified in reviews of child studies was deemed "inconclusive" (2 of 5 studies). While a number of reviews have examined the causes of obesity, the methodology and conclusions varied widely, and few were conducted systematically. Currently, no consensus exists across published literature reviews regarding the primary cause of the obesity epidemic, and more research, particularly prospective studies using state-of-the-art measures, is warranted.

The emerging role of microRNAs and nutrition in modulating health and disease.

Understanding the molecular mechanisms that inform how diet and dietary supplements influence health and disease is an active research area. One such mechanism concerns the role of diet in modulating the activity and function of microRNAs (miRNAs). miRNAs are small noncoding RNA molecules that are involved in posttranscriptional gene silencing and have been shown to control gene expression in diverse biological processes including development, differentiation, cell proliferation, metabolism, and inflammation as well as in human diseases. Recent evidence described in this review highlights how dietary factors may influence cancer, cardiovascular disease, type 2 diabetes mellitus, obesity, and nonalcoholic fatty liver disease through modulation of miRNA expression. Additionally, circulating miRNAs are emerging as putative biomarkers of disease, susceptibility, and perhaps dietary exposure. Research needs to move beyond associations in cells and animals to understanding the direct effects of diet and dietary supplements on miRNA expression and function in human health and disease.

Transcriptomic responses provide a new mechanistic basis for the chemopreventive effects of folic acid and tributyrin in rat liver carcinogenesis.

The steady increase in the incidence and mortality of hepatocellular carcinoma (HCC) signifies a crucial need to understand better its pathogenesis to improve clinical management and prevention of the disease. The aim of this study was to investigate molecular mechanisms for the chemopreventive effects of folic acid and tributyrin alone or in combination on rat hepatocarcinogenesis. Male Wistar rats were subjected to a classic "resistant hepatocyte" model of liver carcinogenesis and treated with folic acid and tributyrin alone or in combination for 5 weeks during promotion stage. Treatment with folic acid and tributyrin alone or in combination strongly inhibited the development of glutathione-S-transferase placental form (GSTP)-positive foci. Microarray analysis showed significant changes in gene expression. A total of 498, 655 and 940 of differentially expressed genes, involved in cell cycle, p53-signaling, angiogenesis and Wnt pathways, was identified in the livers of rats treated with folic acid, tributyrin or folic acid and tributyrin. A detailed analysis of these differentially expressed genes revealed that treatments inhibited angiogenesis in the preneoplastic livers. This was evidenced by the fact that 30 out of 77 differentially expressed genes common to all three treatments are involved in the regulation of the angiogenesis pathway. The inhibition of angiogenesis was confirmed by reduced levels of CD34 protein. In conclusion, the tumor-suppressing activity of folic acid and tributyrin is associated with inhibition of angiogenesis at early stages of rat liver carcinogenesis. Importantly, the combination of folic acid and tributyrin has stronger chemopreventive effect than each of the compounds alone.

Effects of Preanalytical Sample Collection and Handling on Comprehensive Metabolite Measurements in Human Urine Biospecimens.

Epidemiology studies evaluate associations between the metabolome and disease risk. Urine is a common biospecimen used for such studies due to its wide availability and non-invasive collection. Evaluating the robustness of urinary metabolomic profiles under varying preanalytical conditions is thus of interest. Here we evaluate the impact of sample handling conditions on urine metabolome profiles relative to the gold standard condition (no preservative, no refrigeration storage, single freeze thaw). Conditions tested included the use of borate or chlorhexidine preservatives, various storage and freeze/thaw cycles. We demonstrate that sample handling conditions impact metabolite levels, with borate showing the largest impact with 125 of 1,048 altered metabolites (adjusted P < 0.05). When simulating a case-control study with expected inconsistencies in sample handling, we predicted the occurrence of false positive altered metabolites to be low (< 11). Predicted false positives increased substantially (³63) when cases were simulated to undergo alternate handling. Finally, we demonstrate that sample handling impacts on the urinary metabolome were markedly smaller than those in serum. While changes in urine metabolites incurred by sample handling are generally small, we recommend implementing consistent handling conditions and evaluating robustness of metabolite measurements for those showing significant associations with disease outcomes.

Metabolic Dysregulation and Cancer Risk Program (MeDOC): a transdisciplinary approach to obesity-associated cancers.

With the escalating prevalence of obesity, the association between obesity and cancer is a growing public health concern. Obesity will soon surpass tobacco smoking as the most important preventable cause of cancer. Obesity-driven mechanisms can alter cell functions to induce metabolic changes, chronic inflammation, and insulin resistance that are believed to contribute to cancer risk and development; yet the specific underlying biological mechanisms of obesity-related cancer development are largely unknown. The Metabolic Dysregulation and Cancer Risk Program: a transdisciplinary approach to obesity-associated cancers (MeDOC) is a trans-National Cancer Institute research initiative supported by the Division of Cancer Control and Population Sciences, the Division of Cancer Biology, the Division of Cancer Prevention, and the Center to Reduce Cancer Health Disparities. The overall purpose of the MeDOC Program is to advance our understanding of the underlying mechanisms that connect obesity, metabolic dysregulation, and increased obesity cancer risk as well as identify markers that will enhance cancer risk prediction, improve screening for high-risk individuals, and identify targets for preventive and therapeutic interventions for cancer interception or treatment. This report describes the funded research projects, the Coordinating Center, and the goals of the MeDOC program.

Green Cancer Prevention and Beyond.

The concept of green chemoprevention was introduced in 2012 by Drs. Jed Fahey and Thomas Kensler as whole-plant foods and/or extract-based interventions demonstrating cancer prevention activity. Refining concepts and research demonstrating proof-of-principle approaches are highlighted within this review. Early approaches included extensively investigated whole foods, including broccoli sprouts and black raspberries showing dose-responsive effects across a range of activities in both animals and humans with minimal or no apparent toxicity. A recent randomized crossover trial evaluating the detoxification of tobacco carcinogens by a broccoli seed and sprout extract in the high-risk cohort of current smokers highlights the use of a dietary supplement as a potential next-generation green chemoprevention or green cancer prevention approach. Challenges are addressed, including the selection of dose, duration and mode of delivery, choice of control group, and standardization of the plant food or extract. Identification and characterization of molecular targets and careful selection of high-risk cohorts for study are additional important considerations when designing studies. Goals for precision green cancer prevention include acquiring robust evidence from carefully controlled human studies linking plant foods, extracts, and compounds to modulation of targets for cancer risk reduction in individual cancer types.

The Relationship between Physical Activity, Physical Fitness, Cognition, and Academic Outcomes in School-Aged Latino Children: A Scoping Review.

This scoping review provides an overview of the relationship between physical activity, physical fitness, cognition, and academic outcomes in Latino school-aged children and identifies areas for future research. A primary search was conducted in PubMed, PsycINFO, Web of Science, and ERIC for original-research articles meeting the inclusion criteria; the search results were uploaded into PICO Portal and assessed by two independent reviewers. Of the 488 initial search results, 50 articles were eligible for full-text review, and 38 were included in this review. Most studies were cross-sectional, conducted in the United States or Chile, and included children 5-18 years old. Overall, the majority of articles reported positive associations between physical activity or physical fitness and cognitive outcomes (n = 11/12; 91.7%), and physical activity or physical fitness and academic outcomes (n = 22/28; 78.6%). In sum, this review provided consistent evidence for higher amounts of physical activity and greater physical fitness to be associated with various positive cognitive and academic outcomes in a school-aged Latino population. This scoping review also elucidated a substantial gap in the research regarding study design, with a discernible lack of interventional efforts. Future studies should test physical activity interventional strategies to optimize cognitive and academic outcomes in school-aged Latino populations.

Interstrain differences in the severity of liver injury induced by a choline- and folate-deficient diet in mice are associated with dysregulation of genes involved in lipid metabolism.

Nonalcoholic fatty liver disease (NAFLD) is a major health problem and a leading cause of chronic liver disease in the United States and developed countries. In humans, genetic factors greatly influence individual susceptibility to NAFLD. The goals of this study were to compare the magnitude of interindividual differences in the severity of liver injury induced by methyl-donor deficiency among individual inbred strains of mice and to investigate the underlying mechanisms associated with the variability. Feeding mice a choline- and folate-deficient diet for 12 wk caused liver injury similar to NAFLD. The magnitude of liver injury varied among the strains, with the order of sensitivity being A/J ≈ C57BL/6J ≈ C3H/HeJ < 129S1/SvImJ ≈ CAST/EiJ < PWK/PhJ < WSB/EiJ. The interstrain variability in severity of NAFLD liver damage was associated with dysregulation of genes involved in lipid metabolism, primarily with a down-regulation of the peroxisome proliferator receptor α (PPARα)-regulated lipid catabolic pathway genes. Markers of oxidative stress and oxidative stress-induced DNA damage were also elevated in the livers but were not correlated with severity of liver damage. These findings suggest that the PPARα-regulated metabolism network is one of the key mechanisms determining interstrain susceptibility and severity of NAFLD in mice.