Obese Nonalcoholic Fatty Liver Disease Patients Research Articles

Su1305 Home Parenteral Nutrition Outcome: 33 Years Experience From a National Centre

Background/aim: Nonalcoholic fatty liver disease (NAFLD) is considered to be the most common liver disorder in western countries, with a rising prevalence. NAFLD is strongly associated with the presence and severity of obesity, but there is to date no convincing medical therapy. Thus, weight reduction is still the first-line therapy for NAFLD patients. The aim of this study was to evaluate the efficacy of Optifast 52, a commercial interdisciplinary weight loss program, with special emphasis on the adipokines leptin and adiponectin in NAFLD patients. Methods: A total of 72 participants with a BMI of higher than 30 kg/m2 were included. Participants attended weekly over the course of 52 weeks for medical assessment, physical activity, dietary counseling and psychological support. Laboratory values were determined and bioelectrical impedance analyses (BIA) of body composition performed at baseline, and after 26 and 49 weeks. Assessment of NAFLD was carried out using noninvasive parameters: the NAFLD fibrosis score and the BARD score. Results: Of the 72 participants, 42 completed the Optifast program. Initial weight was reduced significantly from 121.1(± 24)kg to 96.3(± 21.9)kg (p=0.0005). Thus, BMI fell from 41.3(± 6.9)kg/m2 to 32.8(± 6.5)kg/m2 and fat mass was reduced from an initial 54.5(± 13.3)kg to 35(± 13.2)kg. The AST/ALT ratio improved with weight loss from 1.17(± 0.5) to 0.83(± 0.26). At baseline, 69% of patients were found to have a pathological AST/ALT ratio, compared to only 24.1% at week 49. The NAFLD score improved from -0.11(± 1.3) to -1.1(± 1.3) on study completion, where a score of -1,455 indicates that liver fibrosis can be excluded. Thus, at the beginning of the study, 14.3% of participants were at low risk of fibrosis, while 28.6% were at high risk. This changed to 39.3% and 3.6% at week 49, respectively. The BARD score improved significantly from 3.5(± 0.87) (baseline) to 2.6(± 1.1) (week 49), coincidentally with an improvement of the leptin/adiponectin ratio from initial 1.16(±0.96) to 0.31(±0.25) (p=0.0005). Conclusion: These data clearly demonstrate the Optifast 52 interdisciplinary weight reduction program to effectively reduce not only liver parameters, but also scores for estimating NAFLD in obese patients. There is evidence in these data that especially the combination of weight reduction through diet and activity has a positive impact on the leptin/adiponectin ratio. As long as no medication is available for this purpose, weight reduction in the form of an interdisciplinary weight management program is therefore a suitable therapy for NAFLD.

Relationship Between Visceral Adipose Tissue and Adiponectin, Inflammatory Markers and Thyroid Hormones in Obese Males with Hepatosteatosis and Insulin Resistance

In our detailed analysis of the recent academic publications, we have not found sufficient evidence regarding the changes of metabolism that occur in cases of insulin resistance (IR) and nonalcoholic fatty liver disease (NAFLD). We aimed to investigate the changes in various biomarkers of obese patients by taking into consideration the IR and NAFLD, which occur increasingly together. Obese male patients included in the study (n = 315) were divided into three groups. Group I was determined as mild pathology (n = 129; HOMA-IR ≥2.5 and grade 0 or HOMA-IR <2.5 and grade 1-2 hepatosteatosis), group II as moderate pathology (n = 145; HOMA-IR ≥2.5 and grade 1-2 or HOMA-IR <4 and grade 3 hepatosteatosis) and group III as severe pathology (n = 41; HOMA-IR ≥4 and grade 3 hepatosteatosis). Waist circumference (WC), percent body fat (%BF), visceral adipose tissue (VAT), subcutaneous abdominal fat tissue (SCAT), thyroid volume (Tvol), thyroid hormones, insulin, adiponectin, fibrinogen and ultrasensitive C-reactive protein (us-CRP) were measured in all patients. A negative correlation between adiponectin and HOMA-IR was found (r = -0.4226; p <0.001). In addition, there were significant differences among all three groups with respect to VAT (p <0.01). Moreover total-triiodo-L-thyronine (TT3) and free-triiodo-L-thyronine (fT3) levels were observed first to decrease in group II compared to group I and then to increase in group III (p <0.001). Fibrinogen and us-CRP levels in group III were significantly higher (p <0.001). TT3 and fT3 levels as well as adiponectin, fibrinogen and us-CRP levels may be affected by the relationship between IR and NAFLD in obese patients. Moreover, increased VAT is a more important risk factor than WC, %BF and BMI, with respect to IR and NAFLD.

Free fatty acids repress small heterodimer partner (SHP) activation and adiponectin counteracts bile acid-induced liver injury in superobese patients with nonalcoholic steatohepatitis

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in industrialized countries and may proceed to steatohepatitis (NASH). Apoptosis and free fatty acid (FFA)-induced lipotoxicity are important features of NASH pathogenesis. We have shown a hepatoprotective effect of adiponectin in steatotic livers of hepatitis C virus (HCV) patients and recent data links bile acid (BA) metabolism to the pathogenesis of NAFLD. The aim of this study was to identify potential interactions between BA and FFA metabolism in NAFLD. Liver biopsies and serum samples from 113 morbidly obese patients receiving bariatric surgery, healthy individuals, and moderately obese NAFLD patients were studied. Serum FFA, BA, and M30 were increased in NASH versus simple steatosis, while adiponectin was significantly decreased. The NAFLD activity score (NAS) score correlated with BA levels and reversely with adiponectin. Adiponectin reversely correlated with CD95/Fas messenger RNA (mRNA) and hepatocellular apoptosis. The BA transporter high-affinity Na+ /taurocholate cotransporter (NTCP) and the BA synthesizing enzyme cholesterol 7 alpha-hydroxylase (CYP7A1) were significantly up-regulated in obese patients and hepatoma cells exposed to FFA. Up-regulation of NTCP and CYP7A1 indicate failure to activate small heterodimer partner (SHP) upon farnesoid X receptor (FXR) stimulation by increasing BA concentrations. In line with the NAS score, adiponectin levels were reversely correlated with BA levels. Adiponectin correlated with NTCP and affects Cyp7A1 expression both in vivo and in vitro. BA synthesis and serum BA levels correlated with disease severity in NAFLD, while adiponectin is reversely correlated. FFA exposure prevented SHP-mediated repression of NTCP and Cyp7A1 expression, which lead to increased BA synthesis and uptake. In NASH, BA accumulation induced hepatocyte cell death and late FXR activation failed to prevent hepatocyte injury due to decreased adiponectin levels. Early treatment with FXR ligands and/or adiponectin-receptor agonists might prevent NASH.

Fecal Microbiome and Volatile Organic Compound Metabolome in Obese Humans With Nonalcoholic Fatty Liver Disease

The histopathology of nonalcoholic fatty liver disease (NAFLD) is similar to that of alcoholic liver disease. Colonic bacteria are a source of many metabolic products, including ethanol and other volatile organic compounds (VOC) that may have toxic effects on the human host after intestinal absorption and delivery to the liver via the portal vein. Recent data suggest that the composition of the gut microbiota in obese human beings is different from that of healthy-weight individuals. The aim of this study was to compare the colonic microbiome and VOC metabolome of obese NAFLD patients (n = 30) with healthy controls (n = 30). Multitag pyrosequencing was used to characterize the fecal microbiota. Fecal VOC profiles were measured by gas chromatography-mass spectrometry. There were statistically significant differences in liver biochemistry and metabolic parameters in NAFLD. Deep sequencing of the fecal microbiome revealed over-representation of Lactobacillus species and selected members of phylum Firmicutes (Lachnospiraceae; genera, Dorea, Robinsoniella, and Roseburia) in NAFLD patients, which was statistically significant. One member of phylum Firmicutes was under-represented significantly in the fecal microbiome of NAFLD patients (Ruminococcaceae; genus, Oscillibacter). Fecal VOC profiles of the 2 patient groups were different, with a significant increase in fecal ester compounds observed in NAFLD patients. A significant increase in fecal ester VOC is associated with compositional shifts in the microbiome of obese NAFLD patients. These novel bacterial metabolomic and metagenomic factors are implicated in the etiology and complications of obesity.

Drug-induced liver injury in obesity

Many countries are facing an epidemic of obesity that can be explained, at least in part, by a sedentary life style and calorie overconsumption. This poses a major issue for public health since obesity primarily enhances the risk of various illnesses such as type 2 diabetes, coronary heart disease, some cancers and nonalcoholic fatty liver disease (NAFLD). Consequently, obese patients are consuming on average more drugs than non-obese individuals [1]. This could pose another medical issue, in particular for hepatologists, since many drugs are able to induce liver injury [2,3]. Moreover, there is growing evidence that obesity and NAFLD can increase the risk of drug-induced liver injury (DILI), at least for some drugs [3,4]. Thus, obese patients could be more prone to develop DILI as a consequence of drug overconsumption and an intrinsic susceptibility of their diseased liver to drug-induced hepatotoxicity. Actually, DILI in obese patients could occur as two distinct clinical settings. Indeed, in the context of obesity and relatedmetabolic diseases, some drugs seem to aggravate pre-existing NAFLD whereas others could induce more frequently an acute hepatitis (Fig. 1). Drugs that could aggravate NAFLD in obese patients are tamoxifen, irinotecan,methotrexate and nucleoside reverse transcriptase inhibitors (NRTIs) such as stavudine and didanosine (Table 1 in Fig. 1) [3,5–7]. Aggravation of NAFLD has also been documented in different animal models with rosiglitazone, tetracycline, phenobarbital and pentoxifylline (Table 1 in Fig. 1) [3,8]. Drugs that could induce acute liver injurymore often in obese individuals are the volatile halogenated anesthetic halothane and isoflurane, acetaminophen (APAP), and other drugs such as losartan, ticlopidine and omeprazole (Table 1 in Fig. 1) [3,9–11]. However, it is noteworthy that the list of drugs in Table 1 is temporary and should expand in the future asDILI in the context of obesity is gaining growing attention. In this ‘‘Snapshot’’ article, I will put forward several potentialmechanismswhereby drugs can bemore hepatotoxic in obese individuals. Since these mechanisms have mostly been discovered during experimental studies, any extrapolation to humans should be done with caution. Drug-induced worsening of NAFLD could be explained by different mechanisms (Fig. 1B). Regarding fatty liver, some drugs could be able to stimulate lipogenesis in steatotic liver, but not

Expression of Inflammation-Related Genes Is Altered in Gastric Tissue of Patients with Advanced Stages of NAFLD

Obesity is associated with chronic low-grade inflammation perpetuated by visceral adipose. Other organs, particularly stomach and intestine, may also overproduce proinflammatory molecules. We examined the gene expression patterns in gastric tissue of morbidly obese patients with nonalcoholic fatty liver disease (NAFLD) and compared the changes in gene expression in different histological forms of NAFLD. Stomach tissue samples from 20 morbidly obese NAFLD patients who were undergoing sleeve gastrectomy were profiled using qPCR for 84 genes encoding inflammatory cytokines, chemokines, their receptors, and other components of inflammatory cascades. Interleukin 8 receptor-beta (IL8RB) gene overexpression in gastric tissue was correlated with the presence of hepatic steatosis, hepatic fibrosis, and histologic diagnosis of nonalcoholic steatohepatitis (NASH). Expression levels of soluble interleukin 1 receptor antagonist (IL1RN) were correlated with the presence of NASH and hepatic fibrosis. mRNA levels of interleukin 8 (IL8), chemokine (C-C motif) ligand 4 (CCL4), and its receptor chemokine (C-C motif) receptor type 5 (CCR5) showed a significant increase in patients with advanced hepatic inflammation and were correlated with the severity of the hepatic inflammation. The results of our study suggest that changes in expression patterns for inflammatory molecule encoding genes within gastric tissue may contribute to the pathogenesis of obesity-related NAFLD.

Multiple Factors Involved in Nonalcoholic Hepatitis Pathogenesis

Multiple Factors Involved in Nonalcoholic Hepatitis Pathogenesis

Up-Regulation of PPAR-γ mRNA Expression in the Liver of Obese Patients: an Additional Reinforcing Lipogenic Mechanism to SREBP-1c Induction

Triglyceride accumulation in the liver is an early feature in the development of nonalcoholic fatty liver disease (NAFLD) associated with human obesity, which is a multifactorial syndrome and whose underlying mechanisms are beginning to be understood. Liver peroxisome proliferator-activated receptor-γ (PPAR-γ) mRNA expression was measured as a signaling mechanism related to steatosis in obese patients with NAFLD. Liver PPAR-γ and sterol receptor element-binding protein 1c (SREBP-1c) mRNA (real-time RT-PCR), serum total adiponectin (RIA), and high molecular weight (HMW)-adiponectin (ELISA) levels, and insulin resistance (IR) evolution (homeostasis model assessment-IR) were determined in 22 obese NAFLD patients (16 with steatosis and six with steatohepatitis) who underwent subtotal gastrectomy with gastrojejunal anastomosis in Roux-en-Y and 16 nonobese subjects who underwent laparoscopic cholecystectomy (controls). Liver PPAR-γ mRNA levels were 112 and 188% higher (P < 0.05) than control values in obese patients with steatosis and steatohepatitis, respectively, who also exhibited 70 and 62% increases in those of SREBP-1c, concomitantly with IR and lower levels of serum total adiponectin and HMW-adiponectin (P < 0.05). Liver PPAR-γ expression showed positive associations with SREBP-1c mRNA levels (r = 0.86; P < 0.0001), serum insulin levels (r = 0.39; P < 0.01), and homeostasis model assessment-IR (r = 0.60; P < 0.0001), and negative correlations with total adiponectin (r = -0.37; P < 0.01) and HMW-adiponectin (r = -0.51; P < 0.001) levels in serum. PPAR-γ is up-regulated in the liver of obese patients with NAFLD, representing an additional reinforcing lipogenic mechanism to SREBP-1c induction in the development of hepatic steatosis.

Decreased Liver Fatty Acid Δ‐6 and Δ‐5 Desaturase Activity in Obese Patients

Steatosis in obese nonalcoholic fatty liver disease (NAFLD) patients is a clinicopathological condition associated with depletion of n-3 polyunsaturated fatty acids (PUFA), a feature that may be related to PUFA desaturation. Liver Delta-6 and Delta-5 desaturase (Delta-6D and Delta-5D) activities, homeostasis model assessment of insulin resistance (HOMA(IR)), and ferric reducing ability of plasma (FRAP) were evaluated in 13 obese patients who underwent subtotal gastrectomy with gastro-jejunal anastomosis in Roux-en-Y and 15 nonobese patients who underwent laparoscopic cholecystectomy (controls). Liver Delta-6D and Delta-5D activities in obese patients were 87% and 66% lower than controls (P < 0.001), respectively, with a 62% diminution in the Delta-6D/Delta-5D activity ratio (P < 0.02). Delta-6D inversely correlated with both HOMA(IR) (r = -0.70, P < 0.0001) and oxidative stress assessed as the reciprocal value of FRAP (r = -0.40, P < 0.05). Delta-5D negatively correlated with HOMA(IR) (r = -0.48, P < 0.01) but not with FRAP(-1) (r = -0.13, not significant). In conclusion, liver PUFA desaturation is diminished in obese NAFLD patients, in association with underlying insulin resistance and oxidative stress, which may play a role in altering lipid metabolism favoring fatty infiltration.

Nonalcoholic Fatty Liver Disease Associated with Obstructive Sleep Apnea: Just a Coincidence?

Obesity is associated with obstructive sleep apnea (OSA) and nonalcoholic fatty liver disease (NAFLD). It has been shown that OSA could be an independent risk factor for NAFLD. OSA could cause not only insulin resistance but worse NAFLD through nocturnal hypoxemia. This study aimed to evaluate the frequency of OSA and NAFLD in obese patients and the relationship between OSA, insulin resistance, and severity of steatohepatitis (nonalcoholic steatohepatitis (NASH)). Forty obese patients submitted to bariatric surgery were evaluated. Sleep studies, fasting blood glucose, serum insulin, homeostasis model assessment (HOMA-IR), and liver enzymes were measured. Liver biopsies were evaluated for features of NAFLD including degrees of steatosis, inflammation, cellular ballooning, and fibrosis. NASH was diagnosed in those with steatosis + ballooning or steatosis + fibrosis. The diagnosis of OSA was based on an apnea/hypopnea index (AHI) ≥ 5events/hours. OSA was present in 32 (80.0%), NAFLD in 33 (82.5%), and NASH in 32 (80.0%) patients. Patients with AHI ≥ 15ev/h had higher serum insulin levels (30.0 ± 12.8 vs. 22.6 ± 17.3μU/ml; p = 0.015) and HOMA-IR (7.5 ± 4.0 vs. 5.4 ± 4.1; p = 0.016) when compared with those with AHI < 15ev/h, but no association was found between AHI and NASH (81.0% vs. 78.9%; p = 1.000) or oxihemoglobin desaturation <84% and NASH (81.2% vs. 70.8%; p = 0.709) when these groups were compared. Obese patients had elevated OSA and NAFLD frequencies. OSA was associated with insulin resistance but not with the severity of NASH.

Liver NF‐κB and AP‐1 DNA Binding in Obese Patients

Oxidative stress and insulin resistance (IR) are major contributors in the pathogenesis of nonalcoholic fatty liver disease (NAFLD) and in the progression from steatosis to nonalcoholic steatohepatitis (NASH). Our aim was to assess nuclear factor-kappaB (NF-kappaB) and activating protein-1 (AP-1) activation and Toll-like receptor 4 (TLR4) expression as signaling mechanisms related to liver injury in obese NAFLD patients, and examined potential correlations among them, oxidative stress, and IR. Liver NF-kappaB and AP-1 (electromobility shift assay (EMSA)), TLR4 expression (western blot), ferric reducing ability of plasma (FRAP), and IR evolution (HOMA) were evaluated in 17 obese patients who underwent subtotal gastrectomy with gastro-jejunal anastomosis in Roux-en-Y and 10 nonobese subjects who underwent laparoscopic cholecystectomy (controls). Liver NF-kappaB and AP-1 DNA binding were markedly increased in NASH patients (n = 9; P < 0.05) compared to controls, without significant changes in NAFLD patients with steatosis (n = 8), whereas TLR4 expression was comparable between groups. Hepatic NF-kappaB activation was positively correlated with that of AP-1 (r = 0.79; P < 0.0001); both liver NF-kappaB and AP-1 DNA binding were inversely associated with FRAP (r = -0.43 and r = -0.40, respectively; P < 0.05) and directly correlated with HOMA (r = 0.66 and r = 0.62, respectively, P < 0.001). Data presented show enhanced liver activation of the proinflammatory transcription factors NF-kappaB and AP-1 in obese patients with NASH, parameters that are significantly associated to oxidative stress and IR.

The effect of metformin on leptin in obese patients with type 2 diabetes mellitus and nonalcoholic fatty liver disease

Insulin resistance is a major feature of type 2 diabetes mellitus, obesity and nonalcoholic fatty liver disease (NAFLD). Several studies pointed out the possible role of increased leptin in NAFLD in humans. The aim of this study is to determine the effect of metformin on plasma leptin levels in obese patients with type 2 diabetes mellitus and NAFLD compared with lifestyle interventions. Thirty-four obese patients with newly diagnosed type 2 diabetes mellitus were prospectively followed for 6 months. All patients had ultrasonographic evidence of NAFLD at baseline. The patients were randomized into two groups: group 1 (n = 15) followed lifestyle changes only and group 2 (n = 19) received metformin (1,700 mg/day). At the end of treatment, BMI, WHR, HbA1c, fasting glucose, leptin, HOMA-IR, alanine aminotransferase values decreased in both groups. No significant difference in the end-points was observed between two groups. Only in group 2, LDL decreased and HDL increased significantly. Liver echogenity decreased significantly at the end of study in both groups. The percentage of patients who no longer had evidence of NAFLD was not significantly different between the groups (20% of patients on lifestyle intervention vs. 16% of patients on metformin). The data demonstrate that, metformin and lifestyle interventions equally affected the plasma leptin levels, BMI and degree of NAFLD in obese patients with type 2 diabetes mellitus. In addition, the effects of metformin on the variables were not found to be mediated by leptin.

Effects of weight loss on liver and erythrocyte polyunsaturated fatty acid pattern and oxidative stress status in obese patients with non-alcoholic fatty liver disease.

Our aim was to study the influence of weight loss on the fatty acid (FA) composition of liver and erythrocyte phospholipids and oxidative stress status in obese, non-alcoholic, fatty liver disease (NAFLD) patients. Seven obese NAFLD patients who underwent subtotal gastrectomy with a gastro-jejunal anastomosis in roux and Y were studied immediately and 3 months after surgery. Seven non-obese patients who underwent anti-reflux surgery constituted the control group. Serum F2-isoprostane levels were measured by GS/NICI-MS/MS and FA composition was determined by GC. At the time of surgery, controls and obese patients exhibited a hepatic polyunsaturated fatty acid (PUFA) pattern that correlated with that of erythrocytes. Three months after surgery, NAFLD patients lost 21% of initial body weight; serum F2-isoprostane levels decreased by 76%; total PUFA, long-chain PUFA (LCPUFA), n-3 PUFA, and n-3 LCPUFA increased by 22, 29, 81, and 93%, respectively; n-6/n-3 LCPUFA ratio decreased by 51%; docosahexaenoic acid/docosapentaenoic acid ratio increased by 19-fold; and the n-3 product/precursor ratio (20: 5 + 22: 5 + 22: 6)/18: 3 increased by 164% (p<0.05). It is concluded that weight loss improves the n-3 LCPUFA status of obese patients in association with significant amelioration in the biomarkers of oxidative stress, membrane FA insaturation, and n-3 LCPUFA biosynthesis capacity, thus representing a central therapeutic issue in the improvement of obesity-related metabolic alterations involved in the mechanism of hepatic steatosis.

Obstructive sleep apnoea and nonalcoholic fatty liver disease: risk factor or just coincidence?

Obstructive sleep apnoea and nonalcoholic fatty liver disease: risk factor or just coincidence?

Effects of weight loss on liver and erythrocyte polyunsaturated fatty acid pattern and oxidative stress status in obese patients with non-alcoholic fatty liver disease

Our aim was to study the influence of weight loss on the fatty acid (FA) composition of liver and erythrocyte phospholipids and oxidative stress status in obese, non-alcoholic, fatty liver disease (NAFLD) patients. Seven obese NAFLD patients who underwent subtotal gastrectomy with a gastro-jejunal anastomosis in roux and Y were studied immediately and 3 months after surgery. Seven non-obese patients who underwent anti-reflux surgery constituted the control group. Serum F2-isoprostane levels were measured by GS/NICI-MS/MS and FA composition was determined by GC. At the time of surgery, controls and obese patients exhibited a hepatic polyunsaturated fatty acid (PUFA) pattern that correlated with that of erythrocytes. Three months after surgery, NAFLD patients lost 21% of initial body weight; serum F2-isoprostane levels decreased by 76%; total PUFA, long-chain PUFA (LCPUFA), n-3 PUFA, and n-3 LCPUFA increased by 22, 29, 81, and 93%, respectively; n-6/n-3 LCPUFA ratio decreased by 51%; docosahexaenoic acid/docosapentaenoic acid ratio increased by 19-fold; and the n-3 product/precursor ratio (20: 5 + 22: 5 + 22: 6)/18: 3 increased by 164% (p<0.05). It is concluded that weight loss improves the n-3 LCPUFA status of obese patients in association with significant amelioration in the biomarkers of oxidative stress, membrane FA insaturation, and n-3 LCPUFA biosynthesis capacity, thus representing a central therapeutic issue in the improvement of obesity-related metabolic alterations involved in the mechanism of hepatic steatosis.

“Buffalo” hump in nonalcoholic fatty liver disease

I read with interest the recent article by Cheung et al.1 regarding the impact of fat distribution, as estimated by several anthropometric parameters, on the severity of nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome in obese NAFLD patients. Notably, they found that dorsocervical lipohypertrophy (“buffalo” hump) was the single greatest predictor of the histological severity of NAFLD, whereas waist circumference was the greatest predictor of the severity of metabolic syndrome.1 Dorsocervical lipohypertrophy (DCL) was diagnosed only clinically but no quantitative measure (for example, ultrasound imaging) was used for diagnosing the “hump” at the base of the neck. Obviously, this is a major limitation of the study. Additionally, it is conceivable that the differential impact of DCL and waist circumference on the severity of NAFLD histology and metabolic syndrome is simply due to the fact that they are only indirect and crude indices of abdominal visceral fat distribution.2 A direct and more accurate measure of abdominal visceral fat, obtained by computed tomography or magnetic resonance imaging,2 would be useful to explore this issue adequately. However, the authors have interestingly shown that DCL, which is commonly seen in Cushing's syndrome, is a highly prevalent condition (28.5%) in obese NAFLD patients,1 thus suggesting an underlying subclinical hypercortisolism in NAFLD. Regarding this, recent studies have consistently shown a subclinical hypothalamo-pituitary-adrenal (HPA) axis dysfunction in NAFLD. Westerbacka et al.3 reported that obese men with higher liver fat content (as evaluated by magnetic resonance imaging spectroscopy) have a selective increase in 24-hour urinary excretion of 5-beta-reduced cortisol metabolites and a lower ratio of urinary cortisol/cortisone metabolites than men with lower liver fat content. Saruc et al.4 found that postmenopausal women with NAFLD, as assessed by ultrasound, have higher plasma dehydroepiandrosterone levels than controls. Others have shown that obese individuals5 and overweight type 2 diabetic patients6 with ultrasonographically diagnosed NAFLD have higher 24-hour urinary free cortisol excretion and postdexamethasone suppression cortisol concentrations than nonsteatotic controls. More importantly, we have recently demonstrated that overweight patients with biopsy-proven NAFLD have a subclinical, chronic HPA axis activation (as reflected by the increased, albeit still normal, 24-hour urinary free cortisol values and the blunted suppression of cortisol levels by 1.0 mg-dexamethasone with normal serum corticosteroid-binding globulin concentrations) that is correlated to the histopathological severity of NAFLD (that is, necro-inflammatory grade and fibrosis stage) independently of multiple potential confounders, including insulin resistance and metabolic syndrome components.7 Overall, therefore, the evidence from these studies,3-7 although only correlative in nature, suggests the hypothesis that overweight/obese NAFLD patients have a subtle HPA axis dysfunction that is strongly correlated with the severity of NAFLD histology, leading to subclinical cortisol overproduction that might be implicated in the development/progression of NAFLD. Future prospective and interventional (by using a cortisol inhibitor or specific 11beta-hydroxysteroid dehydrogenase-type 1 inhibitors) studies are obviously needed to validate this hypothesis and to better understand the underlying biological mechanisms linking HPA axis dysfunction to the development of NAFLD. Giovanni Targher M.D.*, * Section of Endocrinology, Department of Biomedical and Surgical Sciences, University Hospital, Verona, Italy.

Increased production of IL-1α and TNF-α in lipopolysaccharide-stimulated blood from obese patients with non-alcoholic fatty liver disease

Enhanced pro-inflammatory cytokine production is considered a pathogenic factor in non-alcoholic fatty liver disease (NAFLD). Peripheral blood production of interleukin-1α (IL-1α) and tumor necrosis factor-α (TNF-α) was studied in relation to the severity of histological changes of the liver in obese NAFLD patients. Basal levels in serum and production of IL-1α and TNF-α in peripheral blood cell cultures after stimulation with lipopolysaccharide (enzyme-linked immunoabsorbent assays) were measured in 11 patients with steatosis and 15 with steatohepatitis, who underwent gastrectomy with a gastro-jejunal anastomosis in roux and Y, and in 9 controls who underwent anti-reflux surgery. Production of IL-1α and TNF-α was 122 and 67% higher in patients with steatosis than control values, respectively. In patients with steatohepatitis, IL-1α production was 300 and 80% higher and that of TNF-α 110 and 26% higher, as compared with controls and steatosis patients, respectively. Production of IL-1α was positively correlated with that of TNF-α ( r = 0.78, p < 0.0001). IL-1α and TNF-α production were both positively correlated with the degree of steatosis ( r = 0.68, p < 0.001 and r = 0.74, p < 0.0001) and steatohepatitis ( r = 0.77 and r = 0.75, p < 0.0001) at liver biopsy, and with the homeostasis model assessment index ( r = 0.73, p < 0.0001 and r = 0.63, p < 0.01), respectively. Basal serum IL-1α and TNF-α levels were comparable in the three groups studied. It is concluded that elevated production of IL-1α and TNF-α by in vitro stimulated whole blood cell cultures occurs in NAFLD obese patients, which might play a pathophysiological role upon inflammatory leukocyte infiltration of the liver.

Relationship between in vivo chlorzoxazone hydroxylation, hepatic cytochrome P450 2E1 content and liver injury in obese non-alcoholic fatty liver disease patients

The aim of the present study was to test the hypothesis that induction of cytochrome P450 2E1 (CYP2E1) in the liver of patients with non-alcoholic fatty liver disease (NAFLD) is correlated both with the in vivo activity of the cytochrome and with the development of liver injury. For this purpose, the liver content of CYP2E1 was determined by Western blot and the CYP2E1 activity by the in vivo hydroxylation of chlorzoxazone (CLZ). The study groups were obese women with an average body mass index (BMI) of 40.3kg/m(2), who underwent therapeutic gastroplasty or gastrectomy with a gastro-jejunal anastomosis. Further, the hepatic histology was determined to establish the pathological score grouping the subjects into three categories: control, steatosis and steatohepatitis. The liver CYP2E1 content and the CLZ hydroxylation of obese patients with steatosis and, particularly, with steatohepatitis were significantly higher than controls and correlated positively with both the severity of the liver damage. These data provide evidence that CYP2E1 would be involved in the mechanism of liver injury found in obese NAFLD patients. Also, the correlation between liver CYP2E1 content and in vivo CLZ hydroxylation would validate the latter as a reliable indicator of liver injury in NAFLD, thus providing a simple and not invasive method to study these patients.

Predictors of Nonalcoholic Steatohepatitis (NASH) in Obese Patients Undergoing Gastric Bypass

Nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH) are conditions gaining increasing recognition in hepatology as a potential cause of cirrhosis and end-stage liver disease. Obesity is one of the main risk factors. The aims of this study were to determine the frequency of NAFLD in obese patients and to identify variables that predict NASH. A prospective study was conducted of obese patients undergoing gastric bypass over a 20-month period. Assessment included liver function tests and evaluation of insulin resistance with the homeostatic model assessment (HOMA-IR). Liver biopsy was performed in all patients at the time of surgery. Clinical and biochemical variables were analyzed using a multivariate analysis to identify independent predictors of NASH. 127 consecutive patients were included (62% female, 38% male, mean age 40+/-11 years, mean body mass index 42+/-6 kg/m(2)). Arterial hypertension was present in 52 patients (41%) and type 2 diabetes in 18 (14%). NAFLD was confirmed in 80 patients (63%), 47 (37%) had simple steatosis, and 33 (26%) had NASH. Cirrhosis was found in 2 patients corresponding to 1.6% of the total population. On multivariate analysis, AST >31 (IU/L) (OR 3.38, CI 1.17-9.8) and HOMA-IR >5.8 (OR 4.18, CI 1.39-12.49) independently predicted NASH. NAFLD is highly prevalent in morbidly obese patients. A high proportion of these patients exhibit NASH on histological examination. Insulin resistance represents the main predictor of NASH.

Insulin resistance and ferritin as major determinants of nonalcoholic fatty liver disease in apparently healthy obese patients.

The aims of this study were to test the possible association between nonalcoholic fatty liver disease (NAFLD) and iron and insulin resistance, and to determine the prevalence of NAFLD in apparently healthy obese subjects. Cross-sectional, clinical epidemiologic study. A total of 210 apparently healthy obese patients, aged from 18 to 65 y, with a body mass index (BMI) of 28 kg/m2 or more, were enrolled in a body weight reduction program in our hospital. All the subjects underwent screening and preprogram examinations, including anthropometric data measurements, biochemistry testing, and ultrasonography of the liver. NAFLD was defined as fatty liver diagnosed by ultrasonography plus persistent elevation of alanine aminotransferase (ALT) levels. Of the 210 patients, 80% (168/210) had fatty liver. Persistent ALT elevation in two separate tests was further detected in 25.6% (43/168) of patients. Multiple logistic regression analysis showed waist circumference and insulin resistance to be independently associated with fatty liver. Serum ferritin level and insulin resistance were two major risk factors predicting NAFLD. The prevalence of NAFLD was 20.5% (43/210) in obese patients. As both hyperinsulinemia induced by insulin resistance and iron overload represented by ferritin elevation might damage hepatocytes, we concluded that these two factors were significantly associated with NAFLD in obese patients.\