Hepatic Macrosteatosis Research Articles

Point-of-care device for the noninvasive assessment of hepatic macrosteatosis in liver donors

BackgroundQuantification of macrosteatosis (MS) in the liver is important given that it has shown to directly correlate with adverse post-liver transplant (LT) outcomes. With advances in medical technology and an implicit understanding of pathology, noninvasive methods of quantitatively assessing MS are in various stages of development. Each of these methods is based on the physical principles of differences between a fat-laden hepatocyte and a normal one. MethodsIn this regard, after a proof-of-concept study on a prototype for a simple, real-time, handheld device using the principle of diffuse reflectance spectroscopy, this study presents an upgraded point-of-care (POC) device for the noninvasive assessment of hepatic MS in liver donors. ResultsThe device was validated on cohort of donor livers and showed a sensitivity (0.0021 V/% fat) and highly correlated (r = 0.9868, P < .0001) with gold-standard liver biopsy. Results showed that this upgraded POC device provides a reliable method for the noninvasive assessment of hepatic MS, which is crucial for selecting suitable donor livers for LT. ConclusionThe device has the potential to be an invaluable apparatus at the hands of the organ-retrieving surgeon. It is noninvasive, portable (handheld), and economic; provides real-time readings of the percentage of MS; and can be efficaciously handled by any member of the organ-retrieving team.

Non-invasive evaluation of hepatic macrosteatosis in deceased donors

IntroductionLiver allocation changes have led to increased travel and expenditures, highlighting the need to efficiently identify marginal livers suitable for transplant. We evaluated the validity of existing non-invasive liver quality tests and a novel machine learning-based model at predicting deceased donor macrosteatosis >30%. MethodsWe compared previously-validated non-invasive tests and a novel machine learning-based model to biopsies in predicting macrosteatosis >30%. We also tested them in populations enriched for macrosteatosis. ResultsThe Hepatic Steatosis Index area-under-the-curve (AUC) was 0.56. At the threshold identified by Youden's J statistic, sensitivity, specificity, positive, and negative predictive values were 49.6%, 58.9%, 14.0%, and 89.7%. Other tests demonstrated comparable results. Machine learning produced the highest AUC (0.71). Even in populations enriched for macrosteatosis, no test was sufficiently predictive. ConclusionCommonly used clinical scoring systems and a novel machine learning-based model were not clinically useful, highlighting the importance of pre-procurement biopsies to facilitate allocation.

Neonatal Orally Administered Zingerone Attenuates Alcohol-Induced Fatty Liver Disease in Experimental Rat Models.

Alcohol intake at different developmental stages can lead to the development of alcohol-induced fatty liver disease (AFLD). Zingerone (ZO) possess hepato-protective properties; thus, when administered neonatally, it could render protection against AFLD. This study aimed to evaluate the potential long-term protective effect of ZO against the development of AFLD. One hundred and twenty-three 10-day-old Sprague-Dawley rat pups (60 males; 63 females) were randomly assigned to four groups and orally administered the following treatment regimens daily during the pre-weaning period from postnatal day (PND) 12-21: group 1-nutritive milk (NM), group 2-NM +1 g/kg ethanol (Eth), group 3-NM + 40 mg/kg ZO, group 4-NM + Eth +ZO. From PND 46-100, each group from the neonatal stage was divided into two; subgroup I had tap water and subgroup II had ethanol solution as drinking fluid, respectively, for eight weeks. Mean daily ethanol intake, which ranged from 10 to 14.5 g/kg body mass/day, resulted in significant CYP2E1 elevation (p < 0.05). Both late single hit and double hit with alcohol increased liver fat content, caused hepatic macrosteatosis, dysregulated mRNA expression of SREBP1c and PPAR-α in male and female rats (p < 0.05). However, neonatal orally administered ZO protected against liver lipid accretion and SREBP1c upregulation in male rats only and attenuated the alcohol-induced hepatic PPAR-α downregulation and macrosteatosis in both sexes. This data suggests that neonatal orally administered zingerone can be a potential prophylactic agent against the development of AFLD.

Hepatic macrosteatosis in the US pediatric deceased liver donor population.

The pediatric obesity epidemic is associated with early development of hepatic macrosteatosis, a hallmark of non-alcoholic fatty LI disease, which is thought to be more rapidly progressive in children than adults. Macrosteatosis in adult allografts is associated with allograft loss, but this has not been examined in pediatric donors. We studied all pediatric potential whole LI donors (2005-2018) who had a LI biopsy in the SRTR (n=862) and whose LI was transplanted (n=862). Macrosteatosis was abstracted from biopsy reports and compared to values in the SRTR standard analytic file. Recipients of macrosteatotic pediatric allografts were matched 1:1 to recipients of non-macrosteatotic pediatric allografts by propensity score matching on donor/recipient variables. All-cause allograft loss was estimated via Kaplan-Meier analysis and Cox proportional hazards model. From 2005 to 2018, the proportion of pediatric donors (age ≥2years) with obesity increased (14.8% to 21.7%; p<.001), as did the proportion of pediatric deceased whole LI-only donor allografts with macrosteatosis (n=10648; 1.8% to 3.9%; p<.001). The median degree of macrosteatosis among macrosteatotic donors was 10% (IQR 5-30). There were no significant differences in all-cause allograft loss between recipients of pediatric LI allografts with and without macrosteatosis at 90days (p=.11) or 1year (p=.14) post-transplant in Kaplan-Meier analysis or a Cox proportional hazards model (p>.05). Obese pediatric LI donors have increased over time and were more likely to have hepatic macrosteatosis; however, pediatric macrosteatosis did not appear to adversely affect recipient outcomes.

Noninvasive Estimation of Hepatic Steatosis by Controlled Attenuation Parameter in Living Donor Liver Transplant.

Estimation of liver fat among living donor candidates is necessary before living donor liver transplant. This study aimed to investigate the usefulness of the controlled attenuation parameter compared with liver biopsy for pretransplant estimation of hepatic steatosis in living liver donors. In this retrospective study, we included all individuals who underwent transient elastography with controlled attenuation parameter and ultrasonography-guided liver biopsy as a part of donor evaluations before living donor liver transplant. Clinical and laboratory data of living donor candidates were reviewed and collected. Of 49 donor candidates included in this study, 21 (42.9%) had different degrees of hepatic macrosteatosis. Of the 21 donor candidates who had hepatic steatosis in liver biopsy, 13 individuals were diagnosed to have steatosis in transient elastography. Of the 28 donor candidates without hepatic steatosis in liver biopsy, 26 individuals showed no steatosis in transient elastography (odds ratio: 21.12; 95% CI, 3.91- 114.08; P < .001). Controlled attenuation parameter was useful in discriminating presence (P = .001) and grade of hepatic steatosis (P = .009) compared with liver biopsy with good sensitivity and specificity. The controlled attenuation parameter is a noninvasive method for detection of hepatic steatosis in living donor candidates and can be used as an adjunct to liver biopsy for screening of living donor candidates before liver transplant.

Abstract 2910: A TGF-β-ALDH2 axis controls liver- brain-gut microbiome driven obesity, metabolic syndrome and cancer

Abstract Background/Aims: ALDH2 (Aldehyde dehydrogenase 2) is associated with multiple human diseases including cancers, Asian flush syndrome (deficiencies affect 35%-40% of East Asians), and alcoholic liver disease. Yet, oncogenic mechanisms and pathways that ALDH2 interacts with remain unclear. Previously we have demonstrated that TGF-β-deficient mutants derived from the loss of Smad3 and its adaptor Sptbn1 are exquisitely sensitive to alcohol, with impaired DNA damage repair. ALDH2 levels are altered in the liver tissues of the mouse mutants, and the Sptbn1-/- phenotype is similar to ALDH2-FancD2 mutants. We, therefore, hypothesized that disruption of TGF-β signaling combined with ALDH2 deficiency would increase the susceptibility of liver diseases and cancer. Methods: Aldh2-/- mice were intercrossed with Sptbn1+/-, Smad3+/- mice. Control mice and intercrosses were fed with high-fat diet (HFD) or chow diet or alcohol diet, or hepatic vagotomy followed by phenotypic and mechanistic analyses through RNA-seq, lipidomics, metabolomics, western blot analyses, RTPCR, structure modeling, cell fractionation, and immunohistochemistry. Fecal samples from these mice underwent shotgun metagenomic sequencing. Results: Strikingly, compared to WT, Aldh2-/-Sptbn1+/- (ASKO) mice on a normal diet develop metabolic syndromes with truncal obesity, insulin resistance, with increased blood glucose (272.3±28.6mg/dl vs 189.9 ±7.0mg/dl, p&amp;lt;0.05), serum triglyceride (185.2±40.0 mg/dl vs 83.7 ±7.8 mg/dl, p&amp;lt;0.05). Nonalcoholic steatohepatitis (NASH), and cancer, with raised ALT and AST levels, also develop in the mutant mice. HFD exacerbated obesity and NASH in Aldh2-/-Sptbn1+/- on HFD with substantial additional visceral fat accumulation and hyperglycemia with Zone 3 hepatic macro-steatosis and inflammation, which correlated with increased fatty acid metabolism and gluconeogenesis. ASKO mice had significantly altered neurotransmitter receptors in the liver including cholinergic receptors (e.g., Chrnb1, and Chrna2) and altered gut microbiome composition with increased abundance of S. pseudoporcinus (Aldh2-/-Smad3+/- vs WT: 85.6±29 vs 2.71 ±1.44, p&amp;lt;0.05) and decreased A. propionicum (ASKO vs WT: 65±21 vs 168±31, p&amp;lt;0.05). Conclusions: Aldh2-/-Sptbn1+/- mice develop metabolic syndrome with alterations in the cholinergic pathway and microbiome species, suggesting a disruption in afferent vagal activity. ALDH2/SPTBN1 is therefore potentially a major liver-brain-gut vagal regulator of obesity. Aldh2 and TGF-β signaling are important in maintaining normal gut microbiome composition. These studies highlight the potential role of the gut-liver axis in regulating obesity and liver disease. With &amp;gt; 35% Asian population harboring ALDH2 alterations, our studies potentially have a high impact on these patient populations with a high risk of metabolic syndrome. Citation Format: Shuyun Rao, Xiaochun Yang, Zhanhuai Wang, Kazufumi Ohshiro, Sobia Zaidi, Wilma Jogunoori, Bryan Nguyen, Keith A. Crandall, Patricia S. Latham, Kirti Shetty, Lopa Mishra. A TGF-β-ALDH2 axis controls liver- brain-gut microbiome driven obesity, metabolic syndrome and cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2910.

Hypothermic oxygenated perfusion with defatting cocktail further improves steatotic liver grafts in a transplantation rat model.

In this study, we evaluated the restoring and defatting effect of hypothermic oxygenated perfusion (HOPE) on severe steatotic liver grafts with a defatting cocktail (DF) in a rat model. Severe (≥60%) hepatic macrosteatosis was induced by a high-fat diet (HFD) for 6weeks, after which the rats were randomly divided into four following groups: Control group, with lean livers being preserved in static cold storage (SCS) at 0°C-4°C for 45minutes; SCS group, with a steatotic liver graft (SLG) being preserved in SCS at 0°C-4°C for 4hours; HOPE group, where SLG was perfused with 3-hours HOPE followed by 1-hours SCS; and HOPE+DF group, HOPE with the addition of DF. Graft function after orthotopic liver transplantation was assessed in terms of mitochondrial function (adenosine triphosphate [ATP], Glycogen), endoplasmic reticulum stress (PPY, GRP78, CHOP, and ATF-6), cell apoptosis (Tunel assay, Caspase-3), inflammatory level (HMGB1, TLR4, IL-1β, IL-6. TNF-α, Factor V), and posttransplantation survival. HOPE protected steatotic liver grafts from microcirculation disturbance and endoplasmic reticulum stress and then promoted ATP and glycogen synthesis that improved mitochondrial function. Meanwhile, under conditions of ischemia-reperfusion injury, it prevented nuclear injury and endothelial damage by suppressing the release of an inflammatory mediator. The high efficacy of HOPE was enhanced after the addition of the DF. DF agents cannot promote the lipid decomposition of the steatotic liver graft at 0°C-4°C, but they can further improve steatotic liver and postoperative survival compared to the HOPE. The defatted steatotic liver grafts can be safely used in rat orthotopic liver transplantation.

Pirfenidone Is an Agonistic Ligand for PPARα and Improves NASH by Activation of SIRT1/LKB1/pAMPK.

Nonalcoholic steatohepatitis (NASH) is recognized by hepatic lipid accumulation, inflammation, and fibrosis. No studies have evaluated the prolonged‐release pirfenidone (PR‐PFD) properties on NASH features. The aim of this study is to evaluate how PR‐PFD performs on metabolic functions, and provide insight on a mouse model of human NASH. Male C57BL/6J mice were fed with either normo diet or high‐fat/carbohydrate diet for 16 weeks and a subgroup also fed with PR‐PFD (300 mg/kg/day). An insulin tolerance test was performed at the end of treatment. Histological analysis, determination of serum hormones, adipocytokines measurement, and evaluation of proteins by western blot was performed. Molecular docking, in silico site‐directed mutagenesis, and in vitro experiments using HepG2 cultured cells were performed to validate PR‐PFD binding to peroxisome proliferator–activated receptor alpha (PPAR‐α), activation of PPAR‐α promoter, and sirtuin 1 (SIRT1) protein expression. Compared with the high‐fat group, the PR‐PFD‐treated mice displayed less weight gain, cholesterol, very low density lipoprotein and triglycerides, and showed a significant reduction of hepatic macrosteatosis, inflammation, hepatocyte ballooning, fibrosis, epididymal fat, and total adiposity. PR‐PFD restored levels of insulin, glucagon, adiponectin, and resistin along with improved insulin resistance. Noteworthy, SIRT1–liver kinase B1–phospho‐5′ adenosine monophosphate–activated protein kinase signaling and the PPAR‐α/carnitine O‐palmitoyltransferase 1/acyl‐CoA oxidase 1 pathway were clearly induced in high fat + PR‐PFD mice. In HepG2 cells incubated with palmitate, PR‐PFD induced activation and nuclear translocation of both PPARα and SIRT1, which correlated with increased SIRT1 phosphorylated in serine 47, suggesting a positive feedback loop between the two proteins. These results were confirmed with both synthetic PPAR‐α and SIRT1 activators and inhibitors. Finally, we found that PR‐PFD is a true agonist/ligand for PPAR‐α. Conclusions: PR‐PFD provided an anti‐steatogenic effect and protection for inflammation and fibrosis.

Hypothermic oxygenated perfusion (HOPE) for fatty liver grafts in rats and humans

Pretreatment of marginal organs by perfusion is a promising opportunity to make more organs available for transplantation. Protection of human donation after cardiac death (DCD) livers by a novel machine perfusion technique, hypothermic oxygenated perfusion (HOPE), was recently established. Herein, we tested whether HOPE is also useful for fatty liver grafts, using a rodent transplant model. Rats were fed over three weeks with a special methionine-choline-deficient diet (MCDD) to induce severe hepatic macrosteatosis (≥60%). Afterwards, livers were transplanted with either minimal or 12h cold storage. Additional liver grafts were treated after 12h cold storage with 1h HOPE before transplantation. Graft injury after orthotopic liver transplantation (OLT) was assessed in terms of oxidative stress, damage-associated molecular patterns release, toll-like receptor-4 activation, cytokine release, endothelial activation, and the development of necrosis and fibrosis. Implantation of cold stored macrosteatotic liver grafts induced massive reperfusion injury after OLT, compared to controls (non-fatty livers). HOPE treatment after cold storage failed to change the degree of steatosis itself, but markedly decreased reperfusion injury after OLT, as detected by less oxidative stress, less nuclear injury, less Kupffer- and endothelial cell activation, as well as less fibrosis within one week after OLT. Protective effects were lost in the absence of oxygen in the HOPE perfusate. HOPE after cold storage of fatty livers prevents significant reperfusion injury and improves graft function, comparable to the effects of HOPE in DCD livers and DCD kidneys. HOPE treatment is easy and may become a universal concept to further expand the donor pool. An increasing number of donor livers contain fat. It is important to harness marginal livers, which may contain fat, as the stock of donor livers is limited. Hypothermic oxygenated perfusion (HOPE) prevents reperfusion injury and improves liver graft function. HOPE offers a simple and low-cost option for treating liver grafts in transplant centers, even after cold storage, instead of transporting machines to the place of procurement. HOPE could be used globally to expand the donor pool.

Hepatic Macrosteatosis Is Partially Converted to Microsteatosis by Melatonin Supplementation in ob/ob Mice Non-Alcoholic Fatty Liver Disease.

BackgroundObesity is a common risk factor for non-alcoholic fatty liver disease (NAFLD). Currently, there are no specific treatments against NAFLD. Thus, examining any molecule with potential benefits against this condition emerged melatonin as a molecule that influences metabolic dysfunctions. The aim of this study was to determine whether melatonin would function against NAFDL, studying morphological, ultrastuctural and metabolic markers that characterize the liver of ob/ob mice.MethodsLean and ob/ob mice were supplemented with melatonin in the drinking water for 8 weeks. Histology and stereology were performed to assess hepatic steatosis and glycogen deposition. Ultrastructural features of mitochondria, endoplasmic reticulum (ER) and their juxtapositions were evaluated in livers of all experimental groups. Furthermore, hepatic distribution and expression of markers of ER and mitochondria (calnexin, ATP sintase β, GRP78 and CHOP) and metabolic dysfunction (RPB4, β-catenin) and cellular longevity (SIRT1) were analyzed.ResultsMelatonin significantly reduced glycemia, identified also by a decrease of hepatic RBP4 expression, reversed macrosteatosis in microsteatosis at the hepatic pericentral zone, enlarged ER-mitochondrial distance and ameliorated the morphology and organization of these organelles in ob/ob mouse liver. Furthermore, in ob/ob mice, calnexin and ATP synthase β were partially restored, GRP78 and CHOP decreased in periportal and midzonal hepatocytes and β-catenin expression was, in part, restored in peripheral membranes of hepatocytes. Melatonin supplementation to ob/ob mice improves hepatic morphological, ultrastructural and metabolic damage that occurs as a result of NAFLD.ConclusionsMelatonin may be a potential adjuvant treatment to limit NAFLD and its progression into irreversible complications.

Characteristics of Recipients Who Achieved Spontaneous Operational Tolerance in Adult Liver Transplantation

BackgroundChronic immunosuppression is associated with unwanted adverse effects and increased morbidities. Long-term acceptance of transplanted organs without the requirement for immunosuppression, or operational tolerance, remains an important goal in clinical transplantation. MethodsWe reviewed the characteristics of recipients who achieved spontaneous operational tolerance after liver transplantation (OLT) among a consecutive series of 1014 adult recipients in a single center. ResultsWe observed 5 cases (0.5%) of operational tolerance. All cases were men who underwent transplantations for hepatitis B virus-related liver cirrhosis. The mean time from OLT to achievement of spontaneous operational tolerance was 83.1 ± 62.9 months (range, 21.3–156.2). Characteristics common to all tolerant recipients were superior graft quality and good pretransplant recipient condition: specifically, high graft–recipient weight ratio (median, 1.18; range, 1.15–2.69), low hepatic macrosteatosis (median, 3; range, 0–15), low score of model for end-stage liver disease (median, 13; range, 7–21), and no history of preoperative intensive care.

A Randomized Controlled Trial Comparing Efficacy of Pentoxifylline and Pioglitazone on Metabolic Factors and Liver Histology in Patients with Non-alcoholic Steatohepatitis

Non-alcoholic steatohepatitis (NASH) involves increased hepatic macrosteatosis due to increased insulin resistance and non-hepatic processes including oxidative stress, apoptosis, and increased pro-inflammatory cytokines. Present study compared the efficacy of pentoxifylline and pioglitazone therapy in improving the metabolic factors and liver histology in patients with NASH. Sixty consecutive biopsy proven NASH patients aged 18-70 years with ALT>1.2 times the upper limit of normal were randomized to receive either pentoxifylline 1200mg/day in three divided doses orally every day or pioglitazone (30mg/day) daily for 6 months. All the patients were also instructed to reduce their calorie intake by 500kcal/day as well as to perform modest exercise (brisk walking) regularly at least 5 days per week. Before and after treatment, liver function tests, serum insulin, C-peptide levels, TNF-α, adiponectin, leptin levels, HOMA-IR and hepatocyte injury and fibrosis scores on liver histology were assessed. Both pentoxifylline and pioglitazone were effective in improving transaminases, insulin resistance (HOMA-IR) and adiponectin levels significantly. TNF-α levels improved with either of the drugs but did not achieve significant levels. Both the drugs improved the markers of acute liver injury. However, only steatosis improved significantly with either of the drugs. Patients treated with pioglitazone had significant improvement in lobular inflammation, portal inflammation and Brunts grade. Brunts grade improved significantly with pioglitazone as compared to pentoxifylline at the end of the therapy. Pioglitazone shows better improvement in both metabolic factors and liver histology in patients with NASH compared to pentoxifylline.

Feasibility and Accuracy of Dual-Source Dual-Energy CT for Noninvasive Determination of Hepatic Iron Accumulation

To retrospectively assess feasibility of dual-source dual-energy (DSDE) computed tomography (CT) for evaluation of hepatic iron accumulation in a liver phantom and liver transplantation candidates and to compare its accuracy with that of 3-T magnetic resonance (MR) imaging. This study was approved by the institutional review board; informed consent was waived. A liver agar phantom containing six tubes of iron (concentrations, 100-5000 mg of iron per 100 mL of solution) was scanned at 80 and 140 kVp with both DSDE mode and single-source dual-energy (SSDE) CT with sequential scanning mode. Difference of averaged attenuation between 80 and 140 kVp at CT (ΔH) was measured and correlated with iron concentration. Thirty-two liver transplant recipients and 55 donors who underwent DSDE CT at 80 and 140 kVp were included. Twenty-three underwent 3-T liver MR with dual-echo in-phase and opposed-phase T1-weighted and spin-echo T2-weighted imaging. Hepatic ΔH was measured at CT. On T1- and T2-weighted MR images, iron indexes were calculated. Degree of iron accumulation and macrosteatosis were determined at histologic examination (reference). Diagnostic performance of ΔH at CT and iron indexes at MR for diagnosing clinically important iron accumulation was evaluated (receiver operating characteristic [ROC] analysis). For phantom study, ΔH obtained from both DSDE mode and SSDE CT with sequential scanning mode was correlated with iron concentration (correlation coefficient, 1.00 and 0.943, respectively; P = .173). ΔH (13.53) in 10 patients with clinically important (≥ 10%) iron accumulation was significantly higher than that (7.39) in 77 patients with normal or mild iron deposition (P < .001). ΔH was significantly correlated with degree of iron accumulation (correlation coefficient, 0.430; P < .001) but not with degree of hepatic macrosteatosis (P = .216). Area under the ROC curve for diagnosing clinically important iron accumulation was 0.881 and 0.897 with CT and MR, respectively (P = .851). DSDE CT is accurate for diagnosing clinically important hepatic iron accumulation without confounding influence of hepatic steatosis, with diagnostic performance on par with MR.

Non-contrasted Computed Tomography for the Accurate Measurement of Liver Steatosis in Obese Patients

BackgroundHepatic macrosteatosis (HMS) is prevalent among high BMI patients, but a lack of validation of non-invasive measures of liver fat hampers non-alcoholic liver disease (NAFLD) investigation in general. Recent work suggests BMI adjusted, non-contrasted computed tomography (nc-CT) attenuation data (Hounsfield units) reflects liver fat accumulation in a normal weight population. However, this and other CT-based HMS studies have only approximated macrosteatosis (%) histologically, but have not validated findings with chemical liver triglyceride (TG) concentrations (mg/gram protein). Also, all previous CT based steatosis studies excluded high BMI subjects, whose habitus may affect properties of the scan. We hypothesized that in high BMI patients nc-CT attenuation measurements expressed in Hounsfield units (HU) accurately estimate liver triglyceride concentrations as well as histological macrosteatosis.MethodsWith informed consent, 15 patients underwent nc-CT scan of the abdomen prior to weight loss surgery with intraoperative wedge and core needle liver biopsy. Mean left lobe nc-CT Hounsfield units (CTL), liver TG (mg/g Pr), HMS (%), BMI (kg/m2), liver-spleen index (CTL/S = hepatic HU/splenic HU), and liver–spleen difference (CTL-S = hepatic HU − splenic HU) were a priori outcomes.ResultsIn 15 patients (11 female) with a BMI of 44.4 ± 1.1 (mean ± SEM), CTL/S, CTL-S, and CTL measures were significantly associated with liver TG concentrations (r = −0.80, P < 0.001; r = −0.80, P < 0.001; and r = −0.71, P < 0.01, respectively; Table 1). Macrosteatosis (%) and liver triglyceride concentration were positively associated (r = 0.83; P < 0.0001). BMI did not correlate strongly to liver triglyceride (r = 0.44, P = NS).ConclusionEstimates of liver fat obtained by nc- CT scans (esp. CTL/S, CTL-S) correlate to chemical measurement of liver triglyceride concentrations, suggesting non-contrasted CT may be a suitable non-invasive “gold standard” for hepatic steatosis quantification in these patients.

Effect of dietary monosodium glutamate on trans fat-induced nonalcoholic fatty liver disease

The effects of dietary monosodium glutamate (MSG) on trans-fatty acid (TFA)-induced nonalcoholic fatty liver disease (NAFLD) are addressed in an animal model. We used Affymetrix microarray analysis to investigate hepatic gene expression and the contribution of visceral white adipose tissue (WAT) to diet-induced NAFLD. Trans-fat feeding increased serum leptin, FFA, HDL-cholesterol (HDL-C), and total cholesterol (T-CHOL) levels, while robustly elevating the expression of genes involved in hepatic lipogenesis, including the transcription factor sterol-regulatory element binding protein 1c. Histological examination revealed hepatic macrosteatosis in TFA-fed animals. Conversely, dietary MSG at doses similar to human average daily intake caused hepatic microsteatosis and the expression of beta-oxidative genes. Serum triglyceride, FFA, and insulin levels were elevated in MSG-treated animals. The abdominal cavities of TFA- or MSG-treated animals had increased WAT deposition compared with controls. Microarray analysis of WAT gene expression revealed increased lipid biosynthetic gene expression, together with a 50% decrease in the key transcription factor Ppargc1a. A combination of TFA+MSG resulted in the highest levels of serum HDL-C, T-CHOL, and leptin. Microarray analysis of TFA+MSG-treated livers showed elevated expression of markers of hepatic inflammation, lipid storage, cell damage, and cell cycle impairment. TFA+MSG mice also had a high degree of WAT deposition and lipogenic gene expression. Levels of Ppargc1a were further reduced to 25% by TFA+MSG treatment. MSG exacerbates TFA-induced NAFLD.

Hepatic steatosis induced by methionine‐choline deficiency alters the response to ischemia/reperfusion

Hepatic steatosis has been associated with poor outcomes in liver surgery and transplantation. The mechanism of this has not been fully elucidated.In the present study, we examined the effect of liver steatosis, induced by a methionine‐choline deficient (MCD) diet, on the response to hepatic ischemia/reperfusion. MCD mice and controls were sacrificed at 3, 6 and 9 weeks and pathologic examination was performed to determine degree of steatosis, inflammation and fibrosis. Mice at these times also underwent 90 min of partial hepatic ischemia followed by 1, 4 and 8 hours of reperfusion. Serum and histological analyses were performed to assess functional and pathologic injury to the liver.At 3, 6 and 9 weeks MCD mice showed progressive fibrosis and consistent severe hepatic macrosteatosis. In control mice, hepatocellular damage, as measured by serum transaminases, was increased as reperfusion time increased. Surprisingly, MCD mice had less necrotic liver injury than control mice. In contrast, liver accumulation of neutrophils, as measured by myeloperoxidase content, was increased in MCD mice compared to controls.The data suggest that the response to ischemia/reperfusion in steatosis induced by the MCD diet is different than other steatotic models. This may be due to progressive inflammatory and fibrotic change and warrants further investigation of the MCD diet model.

Development of Nonalcoholic Steatohepatitis in Insulin-Resistant Liver-Specific S503A Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 Mutant Mice

Liver-specific inactivation of carcinoembryonic antigen-related cell adhesion molecule 1 causes hyperinsulinemia and insulin resistance, which result from impaired insulin clearance, in liver-specific S503A carcinoembryonic antigen-related cell adhesion molecule 1 mutant mice (L-SACC1). These mice also develop steatosis. Because hepatic fat accumulation precedes hepatitis, lipid peroxidation, and apoptosis in the pathogenesis of nonalcoholic steatohepatitis (NASH), we investigated whether a high-fat diet, by causing inflammation, is sufficient to induce hepatitis and other features of NASH in L-SACC1 mice. L-SACC1 and wild-type mice were placed on a high-fat diet for 3 months, then several biochemical and histologic analyses were performed to investigate the NASH phenotype. A high-fat diet caused hepatic macrosteatosis and hepatitis, characterized by increased hepatic tumor necrosis factor alpha levels and activation of the NF-kappaB pathway in L-SACC1 but not in wild-type mice. The high-fat diet also induced necrosis and apoptosis in the livers of the L-SACC1 mice. Insulin resistance in L-SACC1 fed a high-fat diet increased the hepatic procollagen protein level, suggesting a role in the development of fibrosis. A high-fat diet induces key features of human NASH in insulin-resistant L-SACC1 mice, validating this model as a tool to study the molecular mechanisms of NASH.

Adipocyte Death, Adipose Tissue Remodeling, and Obesity Complications

We sought to determine the role of adipocyte death in obesity-induced adipose tissue (AT) inflammation and obesity complications. Male C57BL/6 mice were fed a high-fat diet for 20 weeks to induce obesity. Every 4 weeks, insulin resistance was assessed by intraperitoneal insulin tolerance tests, and epididymal (eAT) and inguinal subcutaneous AT (iAT) and livers were harvested for histological, immunohistochemical, and gene expression analyses. Frequency of adipocyte death in eAT increased from <0.1% at baseline to 16% at week 12, coincident with increases in 1) depot weight; 2) AT macrophages (ATM Phi s) expressing F4/80 and CD11c; 3) mRNA for tumor necrosis factor (TNF)-alpha, monocyte chemotactic protein (MCP)-1, and interleukin (IL)-10; and 4) insulin resistance. ATM Phi s in crown-like structures surrounding dead adipocytes expressed TNF-alpha and IL-6 proteins. Adipocyte number began to decline at week 12. At week 16, adipocyte death reached approximately 80%, coincident with maximal expression of CD11c and inflammatory genes, loss (40%) of eAT mass, widespread collagen deposition, and accelerated hepatic macrosteatosis. By week 20, adipocyte number was restored with small adipocytes, coincident with reduced adipocyte death (fourfold), CD11c and MCP-1 gene expression (twofold), and insulin resistance (35%). eAT weight did not increase at week 20 and was inversely correlated with liver weight after week 12 (r = -0. 85, P < 0.001). In iAT, adipocyte death was first detected at week 12 and remained <or=3%. These results implicate depot-selective adipocyte death and M Phi-mediated AT remodeling in inflammatory and metabolic complications of murine obesity.

Hepatic Macrosteatosis: Predicting Appropriateness of Liver Donation by Using MR Imaging—Correlation with Histopathologic Findings

To retrospectively evaluate the diagnostic performance of magnetic resonance (MR) imaging in predicting the appropriateness of liver donation in potential living liver donors by using histopathologic results as the reference standard. This study was approved by institutional review board; all patients gave informed consent for the use of MR data for future research. Fifty-seven potential liver donors (40 male, 17 female; age range, 17-57 years; mean age, 32 years) underwent dual-echo 1.5-T MR imaging. Two radiologists qualitatively graded each MR image, with consensus for disagreements. Livers were assigned one of three degrees of hepatic steatosis on the basis of changes in hepatic signal intensity (SI) between in-phase and opposed-phase images. For quantitative analysis, a third radiologist calculated mean hepatic and mean splenic SI by averaging 25 hepatic regions of interest and three splenic regions of interest. Relative SI decrease (RSID) in the liver on opposed-phase images compared with in-phase images was calculated. Linear regression analysis was used to correlate RSID with the degree of total steatosis, macrosteatosis, and microsteatosis. Diagnostic performance for predicting the appropriateness of liver donation was analyzed. Histologic findings of macrosteatosis resulted in 52 patients being categorized as appropriate donors, with the remaining five being categorized as inappropriate donors. RSID was correlated with total steatosis (r = 0.850). When the RSID criterion for inappropriateness of liver donation was set at 20%, the sensitivity, specificity, and accuracy were 100%, 92.3%, and 93%, respectively. When RSID was used, four livers that had been misclassified as inappropriate for transplantation were found to have microsteatosis of various degrees and a less than moderate degree of macrosteatosis at histologic analysis. Qualitative and quantitative analyses were comparably accurate. When an RSID criterion of less than 20% was used, dual-echo MR imaging facilitated the correct prediction of appropriateness of liver donation in 53 of 57 patients.