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Background: Exposure to ambient air pollutants has emerged as a risk for metabolic-dysfunction associated steatotic liver disease (MASLD)., Objectives: We sought to examine associations between short-term (prior month) and long-term (prior year) ambient air pollution exposure with hepatic fat fraction (HFF) and liver stiffness in Latino youth with obesity. A secondary aim was to investigate effect modification by patatin-like phospholipase domain-containing protein 3 (PNPLA3) genotype and liver disease severity., Methods: Data was analyzed from 113 Latino youth (age 11-19) with obesity in Southern California. Individual exposure to particulate matter with aerodynamic diameter ≤ 2.5μm (PM 2.5 ), ≤ 10μm (PM 10 ), nitrogen dioxide (NO 2 ), 8-hour maximum ozone (8hrMax-O 3 ), 24-hr O 3 , and redox-weighted oxidative capacity (O x ) were estimated using residential address histories and United States Environmental Protection Agency air quality observations. HFF and liver stiffness were measured using magnetic resonance imaging. Linear models were used to determine associations between short-term and long-term exposure to air pollutants with HFF and liver stiffness. Modification by PNPLA3 and liver disease severity was then examined.wt ) were estimated using residential address histories and United States Environmental Protection Agency air quality observations. HFF and liver stiffness were measured using magnetic resonance imaging. Linear models were used to determine associations between short-term and long-term exposure to air pollutants with HFF and liver stiffness. Modification by PNPLA3 and liver disease severity was then examined., Results: Short-term exposure to 8hrMax-O 3 was positively associated with HFF. Relationships between air pollution exposure and HFF were not impacted by PNPLA3 genotype or liver disease severity. Long-term exposure to 8hrMax-O 3 and O x were positively associated with liver stiffness. Associations between air pollution exposure and liver stiffness depended on PNPLA3 genotype, such that individuals with GG genotypes exhibited stronger, more positive relationships between short-term exposure to PM wt were positively associated with liver stiffness. Associations between air pollution exposure and liver stiffness depended on PNPLA3 genotype, such that individuals with GG genotypes exhibited stronger, more positive relationships between short-term exposure to PM 10 , 8hrMax-O 3 , 24-hr O 3, and liver stiffness than individuals with CC/CG genotypes. In addition, relationships between short-term exposure to NO x and liver stiffness were stronger in those with severe liver disease.wt and liver stiffness than individuals with CC/CG genotypes. In addition, relationships between short-term exposure to NO 2 and liver stiffness were stronger in those with severe liver disease., Discussion: Air pollution exposure may be a risk factor for liver disease among Latino youth with obesity, particularly in those with other preexisting risks for liver damage., Competing Interests: Declaration of Competing Interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Rohit Kohli reports a relationship with Mirum Biopharma that includes: consulting or advisory. Rohit Kohli reports a relationship with Ipsen that includes: consulting or advisory. Michael Goran reports a relationship with YUMI foods that includes: consulting or advisory. Michael Goran reports a relationship with Bobbie Labs that includes: consulting or advisory. Michael Goran receives royalties from Penguin Random House for Sugarproof 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 The Authors. Published by Elsevier Inc. All rights reserved.)

Metabolic dysfunction-associated steatotic liver disease (MASLD) is the most common paediatric liver disease. Latinos have high MASLD risk due to 50% prevalence of GG genotype of PNPLA3. Our primary aim was to evaluate associations between dietary carbohydrates/sugars and liver stiffness in Latino adolescents with obesity. Our secondary aim was to examine effect modification by (a) PNPLA3 genotype or (b) liver disease severity. Data were obtained from 114 Latino adolescents with obesity involved in two prior studies. No associations were seen between dietary carbohydrates/sugars and liver stiffness in the group as a whole. In subjects with GG genotype of PNPLA3, total sugar, fructose, sucrose, and glucose were associated with liver stiffness. Positive relationships between carbohydrate, total sugar, and sucrose and liver stiffness were stronger in those with MASLD and fibrosis compared to those with healthy livers and MASLD without fibrosis., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Bile acids are the catabolic end products of cholesterol metabolism that are best known for their role in the digestion of lipids. In the last two decades, extensive investigation has shown bile acids to be important signaling molecules in metabolic processes throughout the body. Bile acids are ligands that can bind to several receptors, including the nuclear receptor farnesoid X receptor (FXR) in ileal enterocytes. FXR activation induces the expression of fibroblast growth factor (FGF) 15/19, a hormone that can modulate bile acid levels, repress gluconeogenesis and lipogenesis, and promote glycogen synthesis. Recent studies have described a novel intestinal protein, MAM and LDL Receptor Class A Domain containing 1 (MALRD1) that positively affects FGF15/19 levels. This signaling pathway presents an exciting target for treating metabolic disease and bile acid-related disorders., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Wang, Frey and Kohli.)

Abstract: To investigate the effect of high fructose diet on ultrastructure and content of hepatic mitochondria, we randomized 6-8 weeks old male C57Bl6/J mice to ad lib chow or high-fat-high-fructose (HF2) diet for 32 weeks. HF2-fed mice gained more weight, had higher plasma alanine aminotransferase, and fasting glucose levels and increased hepatic triglyceride content at all time points compared to chow-fed mice. HF2-fed mice had lower mitochondrial to nuclear DNA ratio compared to chow-fed mice. HF2-fed mice had lower average mitochondrial surface area and the number of mitochondria compared to chow-fed mice. HF2-fed mice had higher expression of the hepatic endoplasmic reticulum stress marker Chop, compared to chow-fed mice. A diet high in fat and fructose leads to enhanced hepatic mitochondrial aging, depletion, and dysfunction, which may be important determinants of nonalcoholic steatohepatitis pathogenesis., Competing Interests: The authors have no conflict of interest to declare., (Copyright © 2021 by European Society for Pediatric Gastroenterology, Hepatology, and Nutrition and North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition.)

Argonaute 2 (Ago2) is the main component of the RNA-induced silencing complex. We recently showed that liver-specific Ago2-deficiency in mice (L-Ago2 knockout [KO] mice) enhances mitochondrial oxidation and alleviates obesity-associated pathophysiology. However, the precise mechanisms behind the role of hepatic Ago2 in regulating the mitochondrial oxidation associated with glucose metabolism are still unclear. Here, we show that hepatic Ago2 regulates the function of peroxisome proliferator-activated receptor α (PPARα) for oxidative metabolism. In both genetically and diet-induced severe obese conditions, L-Ago2 KO mice developed obesity and hepatic steatosis but exhibited improved glucose metabolism accompanied by lowered expression levels of pathologic microRNAs (miRNAs), including miR-802, miR-103/107, and miR-152, and enhanced expression of PPARα and its target genes regulating oxidative metabolism in the liver. We then investigated the role of hepatic Ago2 in the outcomes of vertical sleeve gastrectomy (VSG) in which PPARα plays a crucial role in a drastic transcription reprogram associated with improved glycemia post VSG. Whereas VSG reduced body weight and improved fatty liver in wild-type mice, these effects were not observed in hepatic Ago2-deficient mice. Conversely, glucose metabolism was improved in a hepatic Ago2-dependent manner post VSG. Treating Ago2-deficient primary hepatocytes with WY-14643, a PPARα agonist, showed that Ago2-deficiency enhances sensitivity to WY-14643 and increases expression of PPARα target genes and mitochondrial oxidation. Our findings suggest that hepatic Ago2 function is intrinsically associated with PPARα that links Ago2-mediated RNA silencing with mitochondrial functions for oxidation and obesity-associated pathophysiology., (© The Author(s) 2021. Published by Oxford University Press on behalf of the Endocrine Society.)

Background and Aims: The augmenter of liver regeneration (ALR) protein is critical for lipid homeostasis and mitochondrial function. We investigated high-fat/high-carbohydrate (HF/HC) diet-induced nonalcoholic fatty liver disease (NAFLD) in wild-type (WT), hepatocyte-specific ALR-knockout (ALR-H-KO), and ALR-heterozygous (ALR-H-HET) mice. ALR was measured in serum of human nonalcoholic steatohepatitis (NASH) and NASH-induced cirrhosis (serum and liver)., Approach and Results: HF/HC feeding decreased ALR expression in all groups of mice. The otherwise normal ALR-H-HET mice gained more weight and steatosis than WT mice when challenged metabolically with the HF/HC diet; ALR-H-KO mice gained the least weight and had the least steatosis. These findings were consistent with correspondingly increased triglycerides and cholesterol and altered expression of carnitine palmitoyltransferase 1a, sterol regulatory element-binding protein, acetyl coenzyme A carboxylase, and fatty acid synthase. All HF/HC-fed mice developed insulin resistance, the magnitude being lower in ALR-H-KO mice. HF/HC-fed ALR-H-HET mice were more resistant to glucose challenge than WT or ALR-H-KO mice. The frequency of tumor necrosis factor alpha-producing, interleukin 6 (IL6)-producing, and IL17-producing cells was greater in ALR-H-KO than ALR-H-HET and lowest in WT mice. HF/HC feeding did not increase their number in ALR-H-KO mice, and the increase in ALR-H-HET was greater than that in WT mice except for IL17 cells. Cluster of differentiation 25-positive (CD25 + ) forkhead box P3-positive CD4 + regulatory T-cell frequency was lower in ALR-H-HET than WT mice and further reduced in ALR-H-KO mice; HF/HC reduced regulatory T-cell frequency only in WT mice. HF/HC-fed ALR-H-HET, but not WT, mice developed fibrosis; and ALR-H-KO mice progressed to cirrhosis. White adipose tissue of HF/HC-fed ALR-deficient mice developed strong inflammation, indicating bidirectional interactions with the liver. Hepatic and serum ALR levels were significantly reduced in patients with NASH-cirrhosis. Serum ALR was also significantly lower in patients with NASH., Conclusions: Hepatic ALR deficiency may be a critical predisposing factor for aggressive NAFLD progression., (© 2020 by the American Association for the Study of Liver Diseases.)

Sugar-sweetened beverage consumption is a known independent risk factor for nonalcoholic steatohepatitis (NASH). Non-caloric sweeteners (NCS) are food additives providing sweetness without calories and are considered safe and/or not metabolized by the liver. The potential role of newer NCS in the regulation of NASH, however, remain unknown. Our study aimed to determine the impact of newer NCS including Rebaudioside A and sucralose on NASH using high fat diet induced obesity mouse model by substituting fructose and sucrose with NCS in the drinking water. We characterized the phenotype of NCS- treated obesity and investigated the alterations of hepatic function and underlying mechanisms. We found that NCS have no impact on weight gain and energy balance in high fat diet induced obesity. However, in comparison to fructose and sucrose, Rebaudioside A significantly improved liver enzymes, hepatic steatosis and hepatic fibrosis. Additionally, Rebaudioside A improved endoplasmic reticulum (ER) stress related gene expressions, fasting glucose levels, insulin sensitivity and restored pancreatic islet cell mass, neuronal innervation and microbiome composition. We concluded that Rebaudioside A significantly ameliorated murine NASH, while the underlying mechanisms requires further investigation.

Background & Aims: No treatment for nonalcoholic fatty liver disease (NAFLD) has been approved by regulatory agencies. We performed a randomized controlled trial to determine whether 52 weeks of cysteamine bitartrate delayed release (CBDR) reduces the severity of liver disease in children with NAFLD., Methods: We performed a double-masked trial of 169 children with NAFLD activity scores of 4 or higher at 10 centers. From June 2012 to January 2014, the patients were assigned randomly to receive CBDR or placebo twice daily (300 mg for patients weighing ≤65 kg, 375 mg for patients weighing >65 to 80 kg, and 450 mg for patients weighing >80 kg) for 52 weeks. The primary outcome from the intention-to-treat analysis was improvement in liver histology over 52 weeks, defined as a decrease in the NAFLD activity score of 2 points or more without worsening fibrosis; patients without biopsy specimens from week 52 (17 in the CBDR group and 6 in the placebo group) were considered nonresponders. We calculated the relative risks (RR) of improvement using a stratified Cochran-Mantel-Haenszel analysis., Results: There was no significant difference between groups in the primary outcome (28% of children in the CBDR group vs 22% in the placebo group; RR, 1.3; 95% confidence interval [CI], 0.8-2.1; P = .34). However, children receiving CBDR had significant changes in prespecified secondary outcomes: reduced mean levels of alanine aminotransferase (reduction, 53 ± 88 U/L vs 8 ± 77 U/L in the placebo group; P = .02) and aspartate aminotransferase (reduction, 31 ± 52 vs 4 ± 36 U/L in the placebo group; P = .008), and a larger proportion had reduced lobular inflammation (36% in the CBDR group vs 21% in the placebo group; RR, 1.8; 95% CI, 1.1-2.9; P = .03). In a post hoc analysis of children weighing 65 kg or less, those taking CBDR had a 4-fold better chance of histologic improvement (observed in 50% of children in the CBDR group vs 13% in the placebo group; RR, 4.0; 95% CI, 1.3-12.3; P = .005)., Conclusions: In a randomized trial, we found that 1 year of CBDR did not reduce overall histologic markers of NAFLD compared with placebo in children. Children receiving CBDR, however, had significant reductions in serum aminotransferase levels and lobular inflammation. ClinicalTrials.gov no: NCT01529268., (Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Lysosomal acid lipase deficiency (LAL-D) is a classic lysosomal storage disorder characterized by accumulation of cholesteryl ester and triglyceride. Although it is associated with progressive liver injury, fibrosis, and end-stage liver disease in children and adolescents, LAL-D frequently presents with nonspecific signs that overlap substantially with other, more common, chronic conditions like nonalcoholic fatty liver disease (NAFLD), metabolic syndrome, and certain inherited dyslipidemias. We present 2 children with NAFLD who achieved clinically significant weight reduction through healthy eating and exercise, but who failed to have the anticipated improvements in aminotransferases and γ-glutamyl transferase. Liver biopsies performed for these "treatment failures" demonstrated significant microvesicular steatosis, prompting consideration of coexisting metabolic diseases. In both patients, lysosomal acid lipase activity was low and LIPA gene testing confirmed LAL-D. We propose that LAL-D should be considered in the differential diagnosis when liver indices in patients with NAFLD fail to improve in the face of appropriate body weight reduction., (Copyright © 2016 by the American Academy of Pediatrics.)

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.

Non-alcoholic fatty liver disease NAFLD is closely associated with the dysregulation of lipid homeostasis. Diet-induced hepatic steatosis, which can initiate NAFLD progression, has been shown to be dramatically reduced in mice lacking the electroneutral Na(+)/H(+) exchanger NHE1 (Slc9a1). In this study, we investigated if NHE1 deficiency had effects in liver that could contribute to the apparent protection against aberrant lipid accumulation. RT-PCR and immunoblot analyses of wild-type and NHE1-null livers revealed an expression profile that strongly suggested attenuation of both de novo lipogenesis and hepatic stellate cell activation, which is implicated in liver fibrosis. This included upregulation of the farnesoid X receptor FXR, peroxisome proliferator-activated receptor PPARγ, its co-activator PGC1α, and sestrin 2, an antioxidant protein involved in hepatic metabolic homeostasis. Furthermore, expression levels of the pro-lipogenic liver X receptor LXRα, and acetyl CoA carboxylases 1 and 2 were downregulated. These changes were associated with evidence of reduced cellular stress, which persisted even upon exposure to a high-fat diet, and the better preservation of insulin signaling, as evidenced by protein kinase B/Akt phosphorylation (Ser473). These results indicate that NHE1 deficiency may protect against NAFLD pathogenesis, which is significant given the availability of highly specific NHE1 inhibitors., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: Our objective was to investigate the role of bile acids in hepatic steatosis reduction after vertical sleeve gastrectomy (VSG)., Design and Methods: High fat diet (HFD)-induced obese C57Bl/6 mice were randomized to VSG, Sham operation (Sham), Sham operation with pair feeding to VSG (Sham-PF), or nonsurgical controls (Naïve). All mice were on HFD until sacrifice. Mice were observed postsurgery and data for body weight, body composition, metabolic parameters, serum bile acid level and composition were collected. Further hepatic gene expression by mRNA-seq and RT-PCR analysis was assessed., Results: VSG and Sham-PF mice lost equal weight postsurgery while VSG mice had the lowest hepatic triglyceride content at sacrifice. The VSG mice had elevated serum bile acid levels that positively correlated with maximal weight loss. Serum bile composition in the VSG group had increased cholic and tauroursodeoxycholic acid. These bile acid composition changes in VSG mice explained observed downregulation of hepatic lipogenic and bile acid synthetic genes., Conclusion: VSG in obese mice results in greater hepatic steatosis reduction than seen with caloric restriction alone. VSG surgery increases serum bile acids that correlate with weight lost postsurgery and changes serum bile composition that could explain suppression of hepatic genes responsible for lipogenesis., (Copyright © 2013 The Obesity Society.)

Background and Aim: Weight loss is an effective treatment for children with nonalcoholic fatty liver disease (NAFLD), but it is extremely difficult to achieve outside of an intensive weight management program. We hypothesized that one can achieve success in improving NAFLD and weight-related outcomes in a structured and focused multidisciplinary clinical program feasible to implement in a gastroenterology clinic., Methods: We prospectively tracked the clinical status of our patients enrolled in a multidisciplinary program of dietary and exercise advice through an institutional review board-approved NAFLD registry. Each patient met with a gastroenterologist and dietitian every 3 months for 30 minutes to set individualized goals and monitor progress., Results: A total of 108 children have been enrolled in the registry, and of the 83 that were eligible for 1-year follow-up and included in the analysis, 39 patients returned, resulting in a 47% follow-up rate. These 39 patients showed statistically significant improvements in mean BMI z score (-0.1 U, P < 0.05), total (-11 mg/dL, P < 0.05) and low-density lipoprotein (9 mg/dL, P < 0.05) cholesterol, and serum alanine aminotransferase levels (-36 U/L) and aspartate aminotransferase levels (-22 U/L) levels., Conclusions: A clinically feasible multidisciplinary program for obese pediatric patients with NAFLD stabilized BMI z score and significantly improved aminotransferase levels at 1-year follow-up.

Background: Fatty liver disease (FLD) is commonly associated with insulin resistance and obesity, but interestingly it is also observed at low insulin states, such as prolonged fasting. Thus, we asked whether insulin is an independent modulator of hepatic lipid accumulation., Methods/principal Findings: In mice we induced, hypo- and hyperinsulinemia associated FLD by diet induced obesity and streptozotocin treatment, respectively. The mechanism of free fatty acid induced steatosis was studied in cell culture with mouse liver cells under different insulin concentrations, pharmacological phosphoinositol-3-kinase (PI3K) inhibition and siRNA targeted gene knock-down. We found with in vivo and in vitro models that lipid storage is increased, as expected, in both hypo- and hyperinsulinemic states, and that it is mediated by signaling through either insulin receptor substrate (IRS) 1 or 2. As previously reported, IRS-1 was up-regulated at high insulin concentrations, while IRS-2 was increased at low levels of insulin concentration. Relative increase in either of these insulin substrates, was associated with an increase in liver-specific fatty acid transport proteins (FATP) 2&5, and increased lipid storage. Furthermore, utilizing pharmacological PI3K inhibition we found that the IRS-PI3K pathway was necessary for lipogenesis, while FATP responses were mediated via IRS signaling. Data from additional siRNA experiments showed that knock-down of IRSs impacted FATP levels., Conclusions/significance: States of perturbed insulin signaling (low-insulin or high-insulin) both lead to increased hepatic lipid storage via FATP and IRS signaling. These novel findings offer a common mechanism of FLD pathogenesis in states of both inadequate (prolonged fasting) and ineffective (obesity) insulin signaling.

Aims/hypothesis: Intra-abdominal transplantation of non-visceral adipose tissue in rodents, simulating increased abdominal fat in obesity, paradoxically improves glucose tolerance and insulin sensitivity. We hypothesised that this improvement is due to transplant-induced enhanced uptake of fatty acids by adipose tissue, thus reducing fatty acid flux into, and triacylglycerol storage in, the liver., Methods: In Experiment 1, mice were sham-operated or received heterologous epididymal white adipose tissue (WAT; EWAT) or visceral WAT (VWAT) transplantation to the portal and splanchnic circulation regions in the visceral cavity. In Experiment 2, inguinal WAT (IWAT) or EWAT was removed and subsequently transplanted to the visceral cavity of the same mouse (autotransplant). IWAT and EWAT autotransplants were repeated in Experiment 3 and compared with heterotransplants., Results: Heterotransplantation of VWAT did not alter glucose tolerance, whereas auto- or hetero-transplantation of EWAT or IWAT significantly improved glucose tolerance. Transplantation-induced improvements in glucose tolerance 4 weeks after surgery coincided with decreased liver triacylglycerol, decreased portal plasma lipids and increased hepatic insulin sensitivity. By 8 weeks, these changes were apparent only in mice with autotransplantation. Heterologous EWAT transplantation-induced glucose improvement persisted without altered liver metabolism., Conclusions/interpretation: Increases in visceral fat, via transplantation of visceral or non-visceral adipose tissue, is not a major risk factor for glucose intolerance. In fact, there are dynamic metabolic improvements following transplantation that include decreased portal lipids and improved liver metabolism, but these improvements are transient under certain circumstances.

Background: The relations between hepatic steatosis and histological features of hepatocyte injury in children with nonalcoholic fatty liver disease have yet to be examined. The aims of the present study were to establish associations between steatosis amount, type, and distribution in a well-characterized group of children with biopsy-proven nonalcoholic fatty liver disease (NAFLD)., Patients and Methods: One hundred eight children with NAFLD seen in 5 centers were studied. Clinical and laboratory data were collected. Hematoxylin-eosin and Masson trichrome stains were evaluated by 2 expert liver pathologists. Steatosis grade (0-3), type (macrovesicular, microvesicular, or mixed), and zone (1, 3, azonal, or panacinar) were determined. The NAFLD activity score and fibrosis stage were determined., Results: Median patient age was 12 years and median body mass index was 31 kg/m. Fibrosis was present in 87%. The median NAFLD activity score was 4. Mild, moderate, and severe steatosis were present in 42%, 34%, and 24% of biopsies, respectively. Macrovesicular steatosis was present in 81% and mixed steatosis was present in 19%. Panacinar distribution of steatosis was most frequent (40%), followed by azonal (27%). Steatosis grade positively correlated with portal inflammation (P = 0.018). Azonal distribution positively correlated with presence of hepatocyte ballooning (P = 0.03). Biopsies with mixed steatosis were approximately 20 times more likely to have megamitochondria than those with macrovesicular steatosis alone (95% confidence interval 2.3-204.9). There was no relation between steatosis amount, type, or distribution to fibrosis stage., Conclusions: Specific histological patterns of steatosis in children are associated with histological markers of steatohepatitis. Ballooning and portal inflammation correlated well with features of steatosis.

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.