Effect of ω-3 fatty acid ethyl esters on apolipoprotein B-48 kinetics in obese subjects on a weight-loss diet: a new tracer kinetic study in the postprandial state

CONTEXT

Dysregulated chylomicron metabolism may account for hypertriglyceridemia and increased risk of cardiovascular disease in obese subjects. Supplementation with ω-3 fatty acid ethyl ester (FAEE) decreases plasma triglyceride. However, its effect on postprandial chylomicron metabolism in obese subjects on a weight-loss diet has not yet been investigated.

OBJECTIVE

We aimed to examine the effect of ω-3 FAEE supplementation on apolipoprotein (apo) B-48 kinetics in obese subjects on a weight-loss diet.

DESIGN, SETTING, AND PATIENTS

We carried out a 12-week, randomized trial of a hypocaloric diet plus 4 g/d ω-3 FAEE supplementation (46% eicosapentaenoic acid and 38% docosahexaenoic acid) (n = 13) compared with a hypocaloric diet alone (n = 12) on postprandial apoB-48 kinetics in obese subjects after ingestion of an oral load. The apoB-48 kinetics were determined using stable isotope tracer kinetics and multicompartmental modeling.

OUTCOMES MEASURES

We evaluated plasma total and incremental apoB-48 0- to 10-hour area under the curves (AUCs) as well as apoB-48 secretion and fractional catabolic rate.

RESULTS

Weight loss with or without ω-3 FAEE supplementation significantly reduced body weight, total fat mass, homeostasis model assessment score, fasting triglyceride concentration, postprandial triglyceride AUC, and increased plasma high-density lipoprotein cholesterol concentration (P < .05 in all). Compared with weight loss alone, weight loss plus ω-3 FAEE significantly (all P < .05) decreased fasting triglyceride (-11%), apoB-48 (-36%) concentrations, postprandial triglyceride (-21%), and apoB-48 (-22%) total AUCs, as well as incremental postprandial triglyceride AUCs (-32%). The ω-3 FAEE also significantly decreased apoB-48 secretion in the basal state, without a significant effect during the postprandial period (3-6 hours). The fractional catabolic rate of apoB-48 increased with both interventions with no significant independent effect of ω-3 FAEE supplementation.

CONCLUSION

Addition of ω-3 FAEE supplementation to a moderate weight-loss diet in obese subjects can significantly improve chylomicron metabolism by independently decreasing the secretion of apoB-48.

Liver transplantation outcomes for Australian Aboriginal and Torres Strait Islanders

An increased liver disease burden has been reported for Aboriginal and Torres Strait Islanders (ATSIs) in Australia; however, few proceed to liver transplantation (LT). We aimed to compare overall survival and graft survival after LT between ATSI and non-ATSI populations, assess the factors influencing survival within ATSIs, and finally examine the proportion of ATSIs undergoing LT. This study was a retrospective review of the Australia and New Zealand Liver Transplant Registry from 1985 to 2012 and examined consecutive primary LT performed in Australia. Overall and graft survival were compared between ATSI and non-ATSI groups. The Accessibility/Remoteness Index of Australia (ARIA) was used to calculate the remoteness of individuals. There were 3493 primary LT performed, and 45 patients (1.3%; 14 children and 31 adults) were ATSIs. The median (range) ages of the ATSI children and adults at the time of LT were 9.6 (0.2-15.3) years and 44.5 (19.5-65.5) years, respectively. There were 10 deaths in the ATSI cohort. The median (range) overall survival was similar for ATSI and non-ATSI children [6.5 (0.1-23.5) years versus 9.0 (0-28.2) years, P = 0.9] and adults [7.1 (0.1-15.7) years versus 6.3 0-26.7) years, P = 0.8]. The cumulative graft survival was similar for ATSI and non-ATSI children (P = 0.8) and adults (P = 0.8). High ARIA scores [hazard ratio (HR) = 1.2, 95% confidence interval (CI) = 1.01-1.53, P = 0.03] in children and blood group O (HR = 3.8, 95% CI = 1.1-12.7, P = 0.03) in adults predicted worse outcomes for ATSIs. Although ATSIs accounted for 4.7% and 1.8% of the Australian pediatric and adult populations, respectively, they represented only 2.2% of pediatric LT recipients (χ(2)  = 8.2, P = 0.004) and 1.1% of adult LT recipients (χ(2)  = 7.9, P = 0.005). In conclusion, overall survival and graft survival after LT are comparable in ATSIs and non-ATSIs. There is a trend toward increased death/retransplantation in ATSIs from remote areas. ATSI children and adults appear to be underrepresented in the Australian LT population.

Image analysis of liver biopsy samples measures fibrosis and predicts clinical outcome

BACKGROUND & AIMS

Histopathological scoring of liver fibrosis mainly measures architectural abnormalities and requires a minimum biopsy size (⩾ 10 mm). Liver collagen quantification may allow use of small size biopsies and improve the prediction of clinical outcomes. This study evaluated the ability of the collagen proportional area (CPA) measurement to predict clinical outcomes.

METHODS

Clinical outcomes were determined using population based data-linkage for chronic hepatitis C (CHC) patients from 1992 to 2012. Quantitative digital image analysis of liver biopsies was used for CPA measurement.

RESULTS

533 patients with a biopsy size ⩾ 5 mm were included. Median follow up was 10.5 years. 26 developed hepatocellular carcinoma (HCC), 39 developed liver decompensation and 33 had liver related death. 453 had Metavir F0-F2 and 80 had F3-F4. CPA ranged from 1.3% to 44.6%. CPA and Metavir stage were independently associated with liver related death. Metavir stage, CPA stage and age were independently associated with HCC. CPA stage (C1: 0%-5%, C2: 5%-10%, C3: 10%-20%, C4: >20%) stratified risk and a significant difference in outcomes was present between all CPA stages for HCC and between C2-C3 and C3-C4 for decompensation and liver related death. The 15 year composite endpoint-free survival was 97% for C1, 89% for C2, 60% for C3, 7% for C4. C4 had significantly worse survival than ⩽ C3 (p<0.001) in cirrhotic patients.

CONCLUSIONS

CPA stage gave additional information regarding risk stratification for adverse clinical outcomes independent of Metavir stage.

Low serum 25-hydroxyvitamin D concentrations associate with non-alcoholic fatty liver disease in adolescents independent of adiposity

BACKGROUND AND AIMS

Non-alcoholic fatty liver disease (NAFLD) and serum 25-hydroxyvitamin D (s25[OH]D) concentrations are both associated with adiposity and insulin resistance (IR) and thus may be pathogenically linked. We aimed to determine the prevalence of vitamin D deficiency in adolescents with NAFLD and to investigate the prospective and cross-sectional associations between s25[OH]D concentrations and NAFLD.

METHODS

Participants in the population-based West Australian Pregnancy (Raine) Cohort had seasonally adjusted s25(OH)D concentrations determined at ages 14 and then 17 years. NAFLD was diagnosed at 17 years using liver ultrasonography. Associations were examined after adjusting for potential confounders. Odds ratios (ORs) and confidence intervals (CIs) are reported per standard deviation in s25(OH)D concentrations.

RESULTS

NAFLD was present in 16% (156/994) of adolescents. The majority of participants with NAFLD had either insufficient (51%) or deficient (17%) vitamin D status. s25(OH)D concentrations at 17 years were inversely associated with risk of NAFLD (OR 0.74, 95% CI 0.56, 0.97; P = 0.029), after adjusting for sex, race, physical activity, television/computer viewing, body mass index, and IR. The effect of s25(OH)D concentrations at 17 years was minimally affected after further adjusting for s25(OH)D concentrations at 14 years (OR 0.76, 95% CI 0.56, 1.03; P = 0.072).

CONCLUSIONS

Lower s25(OH)D concentrations are significantly associated with NAFLD, independent of adiposity and IR. Screening for vitamin D deficiency in adolescents at risk of NAFLD is appropriate, and clinical trials investigating the effect of vitamin D supplementation in the prevention and treatment of NAFLD may be warranted.

Prediction of morbidity and mortality in patients with chronic hepatitis C by non-invasive liver fibrosis models

BACKGROUND & AIMS

Liver fibrosis is prognostic of outcomes among patients with chronic hepatitis C (CHC). We evaluated the accuracy of non-invasive markers and liver biopsy in predicting morbidity and mortality in CHC patients.

METHODS

Compensated CHC patients were evaluated over a 10-year period. Non-invasive markers including Hepascore, FIB-4, APRI and liver biopsy results were retrospectively collated. Follow-up morbidity and mortality data were obtained from the Western Australian Data Linkage System. The prognostic significance of baseline non-invasive markers and biopsy were assessed using Kaplan-Meier analysis.

RESULTS

A total of 406 subjects (64% male, mean age 48 ± 11 years) were followed up for 2385 person-years, during which there were 22 (5.4%) deaths including 14 (3.4%) who died from liver disease or required liver transplantation. Sixteen (3.9%) subjects developed liver decompensation. Hepascore and liver biopsy (P < 0.005) but not APRI or FIB-4 were predictive of overall and liver-related mortality as well as liver decompensation. A Hepascore>0.5 was associated with increased overall mortality [Hazard Ratio (95%CI) 6.7 (2.6-17), P < 0.001], liver-related mortality [32.8 (4.3-250), P = 0.001] and risk of future decompensation [11.8 (3.3-41), P < 0.001], whereas a Hepascore ≤0.5 was associated with a 99% probability of not dying from liver-related causes over 10 years. Hepascore had comparable accuracy with liver biopsy in predicting liver-related mortality with AUROC of 0.86 (95%CI 0.80-0.90) and 0.87 (0.79-0.96), respectively.

CONCLUSION

Hepascore is predictive of overall and liver-related mortality and morbidity in CHC patients with comparable accuracy to liver biopsy. Hepascore may be a useful prognostic marker in clinical practice.

Extrahepatic complications of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease, and is strongly associated with the metabolic syndrome. In the last decade, it has become apparent that the clinical burden of NAFLD is not restricted to liver-related morbidity or mortality, and the majority of deaths in NAFLD patients are related to cardiovascular disease (CVD) and cancer. These findings have fuelled concerns that NAFLD may be a new, and added risk factor for extrahepatic diseases such as CVD, chronic kidney disease (CKD), colorectal cancer, endocrinopathies (including type 2 diabetes mellitus [T2DM] and thyroid dysfunction), and osteoporosis. In this review we critically appraise key studies on NAFLD-associated extrahepatic disease. There was marked heterogeneity between studies in study design (cross-sectional versus prospective; sample size; presence/absence of well-defined controls), population (ethnic diversity; community-based versus hospital-based cohorts), and method of NAFLD diagnosis (liver enzymes versus imaging versus biopsy). Taking this into account, the cumulative evidence to date suggests that individuals with NAFLD (specifically, nonalcoholic steatohepatitis) harbor an increased and independent risk of developing CVD, T2DM, CKD, and colorectal neoplasms. We propose future studies are necessary to better understand these risks, and suggest an example of a screening strategy.

Texture-based classification of liver fibrosis using MRI

PURPOSE

To investigate the ability of texture analysis of MRI images to stage liver fibrosis. Current noninvasive approaches for detecting liver fibrosis have limitations and cannot yet routinely replace biopsy for diagnosing significant fibrosis.

MATERIALS AND METHODS

Forty-nine patients with a range of liver diseases and biopsy-confirmed fibrosis were enrolled in the study. For texture analysis all patients were scanned with a T2 -weighted, high-resolution, spin echo sequence and Haralick texture features applied. The area under the receiver operating characteristics curve (AUROC) was used to assess the diagnostic performance of the texture analysis.

RESULTS

The best mean AUROC achieved for separating mild from severe fibrosis was 0.81. The inclusion of age, liver fat and liver R2 variables into the generalized linear model improved AUROC values for all comparisons, with the F0 versus F1-4 comparison the highest (0.91).

CONCLUSION

Our results suggest that a combination of MRI measures, that include selected texture features from T2 -weighted images, may be a useful tool for excluding fibrosis in patients with liver disease. However, texture analysis of MRI performs only modestly when applied to the classification of patients in the mild and intermediate fibrosis stages.

Tacrolimus-induced thrombotic microangiopathy in orthotopic liver transplant patients: case series of four patients

Thrombotic microangiopathy (TMA) is a potentially fatal complication in solid organ and bone marrow transplant patients, with reported incidence of 0.5-3% and mortality of about 75%. To emphasise the importance of early diagnosis and prompt commencement of therapy results in improved clinical outcomes. A retrospective study of all patients who underwent orthotopic liver transplantation (OLTX) at the Western Australian Liver Transplantation Service from May 1994 to December 2010 was conducted to identify patients who developed tacrolimus-induced TMA. We identified four patients with tacrolimus-induced TMA post-OLTX, derived from a cohort of 104 patients treated with tacrolimus in our institution. The mean age at diagnosis was 40 years, and the mean time of onset was 63 ± 7.5 weeks after OLTX. The indications for OLTX in the four patients were fulminant hepatic failure in three (Wilson disease, paracetamol overdose and post-partum thrombotic thrombocytopenic purpura) and hepatitis C virus-related cirrhosis. All patients had tacrolimus post-OLTX. At diagnosis, tacrolimus was discontinued in all patients, and three of the four patients underwent plasma exchange and all patients improved clinically. Mean duration of follow up was 15 ± 7.5 months. There was no mortality 6 months post-TMA. Early diagnosis with immediate discontinuation or conversion of calcineurin inhibitors and plasma exchange should be offered to OLTX patients with TMA as it results in good outcomes.

Importance of cardiometabolic risk factors in the association between nonalcoholic fatty liver disease and arterial stiffness in adolescents

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease worldwide and is regarded as the hepatic manifestation of the metabolic syndrome. In adults, NAFLD is a determinant of arterial stiffness and cardiovascular risk, independent of the metabolic syndrome. Our aim was to ascertain if NAFLD is associated with arterial stiffness, independent of cardiometabolic factors in a population-based cohort of adolescents. The 17-year-olds (n = 964) from an Australian birth cohort had measures of anthropometry, blood pressure, fasting insulin, glucose, lipids, and NAFLD by ultrasound. Two-step cluster analysis identified youth at high metabolic risk. Measures of arterial stiffness (pulse wave velocity [PWV] and augmentation index corrected for heart rate [AI@75]) were obtained using applanation tonometry. The overall prevalence of NAFLD was 13.3%. The "high risk" metabolic cluster at age 17 years included 16% males and 19% females. Compared to "low risk," the "high risk" cluster participants had greater waist circumference, triglycerides, insulin, systolic blood pressure, and lower high-density lipoprotein (HDL) cholesterol (all P < 0.0001). Those who had NAFLD but were not in the "high risk" metabolic cluster did not have increased PWV or AI@75. However, males and females who had NAFLD in the presence of the metabolic cluster had greater PWV (b = 0.20, 95% confidence interval [CI] 0.01 to 0.38, P = 0.037). Males who had NAFLD in the presence of the metabolic cluster had greater AI@75 (b = 6.3, 95% CI 1.9 to 10.7, P = 0.005).

CONCLUSION

NAFLD is only associated with increased arterial stiffness in the presence of the "high risk" metabolic cluster. This suggests that arterial stiffness related to the presence of NAFLD is predicated on the presence of an adverse metabolic profile in adolescents.

Image analysis of liver collagen using sirius red is more accurate and correlates better with serum fibrosis markers than trichrome

BACKGROUND

Collagen proportional area (CPA) determined by quantitative digital image analysis better quantifies liver fibrosis than histological stage; however, its clinical use has been limited by non-standardized methods.

AIM

This study aimed to compare CPA obtained using different staining methods, magnifications and biopsy sizes.

METHODS

Two hundred and forty-nine patients with chronic hepatitis C who had a liver biopsy and serum fibrosis markers performed were included. CPA was measured either using a sirius red (CPAs) or a trichrome (CPAt) stain.

RESULTS

CPAs measured at 20× and 40× magnifications generated similar outcomes with interclass correlation (ICC) coefficient of 0.98. Compared with trichrome, sirius red staining had much less variation with an ICC coefficient of 0.99 for slides stained in the same batch and 0.92 in different batches. Mean CPAs was higher than mean CPAt by 3.53%, P < 0.001. Morphological analysis found that sirius red detected delicate fibrous septa and spurs better than trichrome. Both CPAs and CPAt correlated well with Metavir stage, whereas CPAs had better ability to detect cirrhosis with the area under ROC curve of 0.95. Overall CPA had superior correlation with serum markers of fibrosis in Metavir F2-F4 than that in F0-F1 and CPAs correlated better with serum fibrosis markers than CPAt in Metavir F0-F1. Multivairate analysis found that HA, α2-macroglobulin, platelet count and albumin were independently correlated with CPAs and only HA was independently correlated with CPAt.

CONCLUSIONS

Sirius red staining for CPA determination was more accurate and reliable for quantifying hepatic collagen compared with trichrome staining.

The Western dietary pattern is prospectively associated with nonalcoholic fatty liver disease in adolescence

OBJECTIVES

Poor dietary habits have been implicated in the development of nonalcoholic fatty liver disease (NAFLD); however, little is known about the role of specific dietary patterns in the development of NAFLD. We examined prospective associations between dietary patterns and NAFLD in a population-based cohort of adolescents.

METHODS

Participants in the Western Australian Pregnancy Cohort (Raine) Study completed a food frequency questionnaire at 14 years and had liver ultrasound at 17 years (n=995). Healthy and Western dietary patterns were identified using factor analysis and all participants received a z-score for these patterns. Prospective associations between the dietary pattern scores and risk of NAFLD were analyzed using multiple logistic regression.

RESULTS

NAFLD was present in 15.2% of adolescents. A higher Western dietary pattern score at 14 years was associated with a greater risk of NAFLD at 17 years (odds ratio (OR) 1.59; 95% confidence interval (CI) 1.17-2.14; P<0.005), although these associations were no longer significant after adjusting for body mass index at 14 years. However, a healthy dietary pattern at 14 years appeared protective against NAFLD at 17 years in centrally obese adolescents (OR 0.63; 95% CI 0.41-0.96; P=0.033), whereas a Western dietary pattern was associated with an increased risk of NAFLD.

CONCLUSIONS

A Western dietary pattern at 14 years in a general population sample was associated with an increased risk of NAFLD at 17 years, particularly in obese adolescents. In centrally obese adolescents with NAFLD, a healthy dietary pattern may be protective, whereas a Western dietary pattern may increase the risk.

Supplementation with n3 fatty acid ethyl esters increases large and small artery elasticity in obese adults on a weight loss diet

Increased arterial stiffness is associated with enhanced risk of cardiovascular disease in obese individuals. Whether n3 fatty acid ethyl ester (FAEE) supplementation improves arterial stiffness in obese participants on a weight loss diet has not yet been investigated. The objective of the study was to carry out a 12-wk randomized, single-blind trial to test the effect of a 25% energy deficit weight loss diet alone (WL) (n = 12) or WL plus 4 g/d Omacor (46% EPA and 38% DHA) supplementation (WL+FAEE) (n = 13) on arterial elasticity in obese adults. Large (C1) and small artery elasticity (C2) were measured by pulse contour analysis of the radial artery. WL alone reduced (P < 0.05 in all) body weight (-3%), waist circumference (-4%), systolic (-3%) and diastolic (-3%) blood pressures, cardiac output (-4%), plasma TG concentration (-25%), and the homeostasis model assessment (HOMA) score (-12%) and increased plasma HDL cholesterol (+9%) and adiponectin (+18%) concentrations. However, WL alone did not alter C1 and C2. The WL+FAEE intervention significantly reduced body weight (-4%), waist circumference (-4%), systolic (-8%) and diastolic (-5%) blood pressures, pulse pressure (-5%), heart rate (-8%), plasma TG concentration (-36%), and HOMA score (-12%) and increased stroke volume (+3%), plasma HDL cholesterol (+6%) and adiponectin concentrations (+28%), and C1 (+20%) and C2 (+22%) artery elasticity. The changes in systolic blood pressure, heart rate, plasma TGs, C1, and C2 were significantly greater in the WL+FAEE group than in the WL group. Supplementation with n3 FAEEs improves C1 and C2 independently of weight loss in obese adults.

Diagnostic performance of a rapid magnetic resonance imaging method of measuring hepatic steatosis

OBJECTIVES

Hepatic steatosis is associated with an increased risk of developing serious liver disease and other clinical sequelae of the metabolic syndrome. However, visual estimates of steatosis from histological sections of biopsy samples are subjective and reliant on an invasive procedure with associated risks. The aim of this study was to test the ability of a rapid, routinely available, magnetic resonance imaging (MRI) method to diagnose clinically relevant grades of hepatic steatosis in a cohort of patients with diverse liver diseases.

MATERIALS AND METHODS

Fifty-nine patients with a range of liver diseases underwent liver biopsy and MRI. Hepatic steatosis was quantified firstly using an opposed-phase, in-phase gradient echo, single breath-hold MRI methodology and secondly, using liver biopsy with visual estimation by a histopathologist and by computer-assisted morphometric image analysis. The area under the receiver operating characteristic (ROC) curve was used to assess the diagnostic performance of the MRI method against the biopsy observations.

RESULTS

The MRI approach had high sensitivity and specificity at all hepatic steatosis thresholds. Areas under ROC curves were 0.962, 0.993, and 0.972 at thresholds of 5%, 33%, and 66% liver fat, respectively. MRI measurements were strongly associated with visual (r(2) = 0.83) and computer-assisted morphometric (r(2) = 0.84) estimates of hepatic steatosis from histological specimens.

CONCLUSIONS

This MRI approach, using a conventional, rapid, gradient echo method, has high sensitivity and specificity for diagnosing liver fat at all grades of steatosis in a cohort with a range of liver diseases.

Association between liver-specific gene polymorphisms and their expression levels with nonalcoholic fatty liver disease

Genetic factors account for a significant proportion of the phenotypic variance of nonalcoholic fatty liver disease (NAFLD); however, very few predisposing genes have been identified. We aimed to (1) identify novel genetic associations with NAFLD by performing a genome-wide association study (GWAS), and (2) examine the biological expression of the strongest genetic associations in a separate cohort. We performed GWAS of a population-based cohort (Raine Study) of 928 adolescents assessed for NAFLD by ultrasound at age 17. Expression of genes with single nucleotide polymorphisms (SNPs) that were associated with NAFLD at a significance level of P < 10(-5) was examined in adults with NAFLD and controls by quantifying hepatic messenger RNA (mRNA) expression and serum levels of protein. After adjustment for sex and degree of adiposity, SNPs in two genes expressed in liver were associated with NAFLD adolescents: group-specific component (GC) (odds ratio [OR], 2.54; P = 1.20 × 10(-6)) and lymphocyte cytosolic protein-1 (LCP1) (OR, 3.29; P = 2.96 × 10(-6)). SNPs in two genes expressed in neurons were also associated with NAFLD: lipid phosphate phosphatase-related protein type 4 (LPPR4) (OR, 2.30; P = 4.82 × 10(-6)) and solute carrier family 38 member 8 (SLC38A8) (OR, 3.14; P = 1.86 × 10(-6) ). Hepatic GC mRNA was significantly reduced (by 83%) and LCP1 mRNA was increased (by 300%) in liver biopsy samples from patients with NAFLD compared to controls (P < 0.05). Mean serum levels of GC protein were significantly lower in patients with NAFLD than controls (250 ± 90 versus 298 ± 90, respectively; P = 0.004); GC protein levels decreased with increasing severity of hepatic steatosis (P < 0.01).

CONCLUSION

The association between GC and LCP1 SNPs and NAFLD as well as altered biological expression implicate these genes in the pathogenesis of NAFLD.

DNA methylation of the IGF2/H19 imprinting control region and adiposity distribution in young adults

Background

The insulin-like growth factor 2 (IGF2) and H19 imprinted genes control growth and body composition. Adverse in-utero environments have been associated with obesity-related diseases and linked with altered DNA methylation at the IGF2/H19 locus. Postnatally, methylation at the IGF2/H19 imprinting control region (ICR) has been linked with cerebellum weight. We aimed to investigate whether decreased IGF2/H19 ICR methylation is associated with decreased birth and childhood anthropometry and increased contemporaneous adiposity.

DNA methylation in peripheral blood (n = 315) at 17 years old was measured at 12 cytosine-phosphate-guanine sites (CpGs), analysed as Sequenom MassARRAY EpiTYPER units within the IGF2/H19 ICR. Birth size, childhood head circumference (HC) at six time-points and anthropometry at age 17 years were measured. DNA methylation was investigated for its association with anthropometry using linear regression.

Results

The principal component of IGF2/H19 ICR DNA methylation (representing mean methylation across all CpG units) positively correlated with skin fold thickness (at four CpG units) (P-values between 0.04 to 0.001) and subcutaneous adiposity (P = 0.023) at age 17, but not with weight, height, BMI, waist circumference or visceral adiposity. IGF2/H19 methylation did not associate with birth weight, length or HC, but CpG unit 13 to 14 methylation was negatively associated with HC between 1 and 10 years. β-coefficients of four out of five remaining CpG units also estimated lower methylation with increasing childhood HC.

Conclusions

As greater IGF2/H19 methylation was associated with greater subcutaneous fat measures, but not overall, visceral or central adiposity, we hypothesize that obesogenic pressures in youth result in excess fat being preferentially stored in peripheral fat depots via the IGF2/H19 domain. Secondly, as IGF2/H19 methylation was not associated with birth size but negatively with early childhood HC, we hypothesize that the HC may be a more sensitive marker of early life programming of the IGF axis and of fetal physiology than birth size. To verify this, investigations of the dynamics of IGF2/H19 methylation and expression from birth to adolescence are required.

Cholesteryl ester transfer protein gene polymorphisms increase the risk of fatty liver in females independent of adiposity

BACKGROUND AND AIM

Environmental factors including excessive caloric intake lead to disordered lipid metabolism and fatty liver disease (FLD). However, FLD demonstrates heritability suggesting genetic factors are also important. We aimed to use a candidate gene approach to examine the association between FLD and single nucleotide polymorphisms (SNPs) in lipid metabolism genes in the adolescent population-based Western Australian Pregnancy (Raine) Cohort.

METHODS

A total 951 seventeen year-olds underwent hepatic ultrasound, anthropometric and biochemical characterization, DNA extraction and genotyping for 57 SNPs in seven lipid metabolism genes (ApoB100, ATGL, ABHD5, MTTP, CETP, SREBP-1c, PPARα). Associations were adjusted for metabolic factors and Bonferroni corrected.

RESULTS

The prevalence of FLD was 16.2% (11.4% male vs 21.2% female, P=0.001). Multivariate analysis of metabolic factors found suprailiac skinfold thickness (SST) to be the major predictor of FLD in females and males (odds ratio [OR] 1.11, 95% confidence interval [CI] 1.08-1.15, P=1.7×10(-10) and OR 1.17, 95%CI 1.13-1.22, P=2.4×10(-11) , respectively). In females, two SNPs in linkage disequilibrium from the CETP gene were associated with FLD: rs12447924 (OR 2.16, 95%CI 1.42-3.32, P=0.0003) and rs12597002 (OR=2.22, 95%CI 1.46-3.41 P=0.0002). In lean homozygotes, the probability of FLD was over 30%, compared with 10-15% in lean heterozygotes and 3-5% in lean wild-types. However, these associations were modified by SST, such that for obese individuals, the probability of FLD was over 30% in all genotype groups.

CONCLUSIONS

Cholesteryl ester transfer protein gene polymorphisms are associated with an increased risk of FLD in adolescent females. The effect is independent of adiposity in homozygotes, thereby placing lean individuals at a significant risk of FLD.

A prospective evaluation of the role of transient elastography for the detection of hepatic fibrosis in type 2 diabetes without overt liver disease

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a major risk factor for the development of non-alcoholic fatty liver disease (NAFLD) and subsequently hepatic fibrosis. Transient elastography (TE) is a rapid, reproducible non-invasive test that may be appropriate as a screening tool for the presence of hepatic fibrosis.

AIM

Assess the utility of TE as a screening tool for the presence of hepatic fibrosis in a T2DM population with no known liver disease.

METHODS

T2DM patients without known liver disease were included. Patients were assessed with TE in addition to biochemical parameters.

RESULTS

A successful TE evaluation could be obtained in 74 of 81 (91%) included subjects. Of these, 26 (35%) had a liver stiffness measurement (LSM) ≥ 7.65 kPa. Sixteen of these subjects had confirmatory liver biopsies with significant (≥ F2 fibrosis) present in 12 (75%) and cirrhosis diagnosed in 2 subjects. 15/16 (94%) had histological steatohepatitis. Compared with those with a lower LSM, subjects with an LSM ≥ 7.65 kPa had higher ALT levels (38.0 ± 21.7 vs 26.1 ± 11.1 U/L, p = 0.021) and increased prevalence of hepatic steatosis by ultrasound (85% vs 63%, p = 0.005).

CONCLUSION

Significant hepatic fibrosis in the T2DM population is frequently under-recognized. TE may be a feasible tool for the screening of T2DM patients for the presence of hepatic fibrosis.

The Framingham risk score and heart disease in nonalcoholic fatty liver disease

The accuracy of the Framingham risk score (FRS) in identifying patients with nonalcoholic fatty liver disease (NAFLD) at higher 10-year coronary heart disease (CHD) risk remains unknown. We aimed at evaluating both the baseline probability of CHD as predicted by the FRS and the actual long-term occurrence of CHD in NAFLD patients. This was a longitudinal study of a community-based cohort. A total of 309 NAFLD patients were followed up for 11.5 ± 4.1 years (total 3554 person-years). The overall calculated 10-year CHD risk was significantly higher in the NAFLD cohort than the absolute CHD risk predicted by the FRS for persons of the same age and gender (10.9 ± 9.3% vs. 9.9 ± 5.9%, respectively, P < 0.0001), and higher in men than women (12.6 ± 10.3% vs. 9.6 ± 8.1%, respectively, P = 0.006). New onset CHD occurred in 34 patients (11% vs. 10.9% predicted at baseline, P = NS), whereas 279 (89%) patients did not develop CHD. Using multivariable analysis, the FRS was the only variable significantly associated with new onset CHD (OR = 1.13, 95% CI = 1.05-1.21; P = 0.001). A FRS cut-point of 11 in women, and 6 in men had a sensitivity of 80% and 74%, respectively, and a negative predictive value of 97% and 93% respectively. NAFLD patients have a higher 10-year CHD risk than the general population of the same age and gender. The FRS accurately predicts the higher 10-year CHD risk in NAFLD patients, and helps identify those patients expected to derive the most benefit from early intervention to prevent CHD events.

Comparative analysis of a putative tuberculosis-susceptibility gene, MC3R, and pseudogene sequences in cattle, African buffalo, hyena, rhinoceros and other African bovids and ruminants

Studies in humans have suggested the possible involvement of melanocortin-3-receptor (MC3R) and other components of the central melanocortin system in host defense against mycobacteria. We report a genomic DNA nucleotide sequence highly homologous to human MC3R in several bovids and non-bovid African wildlife species. Nucleotide sequence analysis indicates that the orthologous genes of cattle and buffalo are highly homologous (89.4 and 90%, respectively) to the human MC3R gene. Sequence results also identified a typical non-functional, duplicated pseudogene, MC3RP, in 7 species from the family Bovidae. No pseudogene was found in animals outside Bovidae. The presence of the pseudogene in tuberculosis-susceptible species could have possible immunomodulatory effects on susceptibility to bovine tuberculosis infection, as well as a considerable influence on energy metabolism and food conversion efficiency.

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) refers to the accumulation of hepatic steatosis not due to excess alcohol consumption. The prevalence of NAFLD is up to 30% in developed countries and nearly 10% in developing nations, making NAFLD the most common liver condition in the world. The pathogenesis of NAFLD is related to insulin resistance and, thus, it is frequently found in individuals who have central obesity or diabetes. Insulin resistance and excess adiposity are associated with increased lipid influx into the liver and increased de novo hepatic lipogenesis, promoting hepatic triglyceride accumulation. Defects in lipid utilization via mitochondrial oxidation and lipid export may also contribute to hepatic lipid build-up. Adipocytokine alterations, lipotoxicity from saturated fatty acids and fructose have been all been implicated in causing hepatocyte injury in NAFLD through pathways involving oxidative and endoplasmic reticulum stress. Clinically, NAFLD is commonly asymptomatic and frequently detected incidentally by blood liver function tests or imaging performed for other reasons. Subjects with NAFLD have a higher mortality rate than the general population and are at increased risk of developing cardiovascular disease and diabetes in the future. Histologically, NAFLD occurs as a spectrum from mild hepatic steatosis only, to non-alcoholic steatohepatitis (NASH) characterized by hepatocellular injury and inflammation, to cirrhosis. A diagnosis of NASH with associated fibrosis heralds a more significant prognosis as it is more likely to progressive to cirrhosis with complications of hepatic failure and hepatocellular carcinoma. Currently, the diagnosis of NASH requires a liver biopsy, however, serum based markers of hepatocyte apoptosis such as cytokeratin-18 fragments offer promise as accurate non-invasive diagnostic tests. Treatment of NAFLD revolves around addressing concomitant metabolic risk factors and improving insulin resistance through weight loss measures and exercise. Insulin sensitizing agents such as pioglitazone and anti-oxidant agents such as vitamin E show some promise in improving liver histology in patients with NASH, however, the long-term benefit of these medications has not been demonstrated.

Complex non-invasive fibrosis models are more accurate than simple models in non-alcoholic fatty liver disease

BACKGROUND AND AIM

Significant hepatic fibrosis is prognostic of liver morbidity and mortality in non-alcoholic fatty liver disease (NAFLD); however, it remains unclear whether non-invasive fibrosis models can determine this end-point. We therefore compared the accuracy of simple bedside versus complex fibrosis models across a range of fibrosis in a multi-centre NAFLD cohort.

METHODS

Simple (APRI, BARD) and complex (Hepascore, Fibrotest, FIB4) fibrosis models were calculated in 242 NAFLD subjects undergoing liver biopsy. Significant (F2-4) and advanced fibrosis (F3,4) were defined using Kleiner criteria. Models were compared using area under the receiver operator characteristic curves (AUC). Cut-offs were determined by Youden Index or 90% predictive values.

RESULTS

For significant fibrosis, non-invasive fibrosis models had modest accuracy (AUC 0.707-0.743) with BARD being least accurate (AUC 0.609, P < 0.05 vs others). Using single cut-offs, sensitivities and predictive values were < 80%; using two cut-offs, > 75% of subjects fell within indeterminate ranges. Simple models had significantly more subjects within indeterminate ranges than complex models (99.1-100% vs 82.1-84.4% respectively, P < 0.05 for all). For advanced fibrosis, complex models were more accurate than BARD (AUC 0.802-0.858 vs 0.701, P < 0.05). Using two cut-offs, complex models had fewer individuals within indeterminate ranges than BARD (11.1-32.3% vs 70.7%, P < 0.01 for all). For cirrhosis, complex models had higher AUC values than simple models.

CONCLUSIONS

In NAFLD subjects, non-invasive models have modest accuracy for determining significant fibrosis and have predictive values less than 90% in the majority of subjects. Complex models are more accurate than simple bedside models across a range of fibrosis.

The natural history of nonalcoholic fatty liver disease with advanced fibrosis or cirrhosis: an international collaborative study

Information on the long-term prognosis of nonalcoholic fatty liver disease (NAFLD) is limited. We sought to describe the long-term morbidity and mortality of patients with NAFLD with advanced fibrosis or cirrhosis by prospectively studying 247 such patients from four international centers (in Australia, USA, UK and Italy). Their natural history was then compared with 264 patients with HCV infection who were either naïve or non-responders to treatment. Both cohorts were Child-Pugh class A and had advanced fibrosis (stage 3) or cirrhosis (stage 4) confirmed by liver biopsy at enrollment. In the NAFLD cohort, followed up for a mean of 85.6 months (range, 6-297), there were 48 (19.4%) liver-related complications and 33 (13.4%) deaths or liver transplants. In the HCV cohort, followed up for 74.9 months (mean; range, 6-238), there were 47 (16.7%) liver-related complications and 25 (9.4%) deaths or liver transplants. When adjusting for baseline differences in age and gender, the cumulative incidence of liver-related complications was lower in the NAFLD than the HCV cohort (P = 0.03), including incident hepatocellular cancer (6 versus 18; P = 0.03), but that of cardiovascular events (P = 0.17) and overall mortality (P = 0.6) were similar in both groups. In the NAFLD cohort, platelet count, stage 4 fibrosis, lowered platelet count, and lowered serum cholesterol and alanine aminotransferase (ALT) levels were associated with liver-related complications; an aspartate aminotransferase/ALT ratio >1 and older age were associated with overall mortality, and higher serum bilirubin levels and stage 4 fibrosis were associated with liver-related mortality.

CONCLUSIONS

Patients with NAFLD with advanced fibrosis or cirrhosis have lower rates of liver-related complications and hepatocellular cancer than corresponding patients with HCV infection, but similar overall mortality. Some clinical and laboratory features predict liver-related complications and other outcomes in patients with NAFLD.