Metabolic and histological features of non-alcoholic fatty liver disease patients with different serum alanine aminotransferase levels

Identification of Nonalcoholic Fatty Liver Disease following Pancreatic Surgery in a Western Cohort Using a Novel Radiographic Technique

BACKGROUND AND AIMS

While traditional risk factors for the development of nonalcoholic fatty liver disease (NAFLD) relate to metabolic syndrome, several Asian studies have suggested a high rate of de novo NAFLD following pancreaticoduodenectomy (PD). The aim of this study is to identify de novo NAFLD after pancreatic surgery and its associated risk factors.

METHODS

A retrospective cohort of patients at a single center that underwent PD or distal pancreatectomy (DP) over 7 years was identified. Pre- and postoperative contrast-enhanced computed tomography scans of the abdomen were reviewed, including attenuation measurements of the liver, spleen, and muscle. Primary outcomes included hepatic attenuation, liver to muscle ratio (LMR), and liver to spleen ratio (LSR).

RESULTS

Of the 96 patients (mean age 64.3) included, 70% underwent PD, and 30% underwent DP. The mean LMR decreased significantly from 1.81 to 1.66 (p=0.02), noted only in men. No interaction effect with LMR was observed with surgical type, chemotherapy, blood loss, pancreatic enzyme replacement, or transaminases. LMR decreased in 55% of subjects.

CONCLUSIONS

Increased fatty infiltration, as evidence by decreased LMR, was found among men that underwent PD and DP within a year of surgery. This may be related to weight loss and malabsorption and deserves further investigation.

Age impacts ability of aspartate-alanine aminotransferase ratio to predict advanced fibrosis in nonalcoholic Fatty liver disease

BACKGROUND AND AIM

While histological differences have been reported between pediatric and adult nonalcoholic fatty liver disease (NAFLD), potential age-related changes in serum transaminases and liver histology remain largely unexplored. Our study sought to investigate the clinical and histological characteristics of NAFLD across age.

METHODS

This was a prospective cross-sectional study of 502 biopsy-proven NAFLD patients. Clinical data were evaluated and compared among different age groups; group A (ages 18-44), B (ages 45-64), and C (≥ ages 65).

RESULTS

34.9, 56.0, and 9.1 % of the cohort were distributed among group A, B, and C, respectively. While the prevalence of nonalcoholic steatohepatitis (NASH) was comparable across age groups, the prevalence of advanced fibrosis increased with age (p = 0.000). Although the mean ALT progressively decreased with age; 87, 64, 56 U/L in group A, B, and C, respectively (p = 0.000), there was no difference in mean AST (p = 0.939) across age. The AST:ALT ratio (AAR) progressively increased from 0.7, 0.9, and 1.1 in group A, B, and C, respectively (p = 0.000). In group C, an AAR ≥ 1 was found in 74 and 40 % of patients with and without advanced fibrosis.

CONCLUSION

With advancing age, ALT levels progressively declined while AST levels remained stable, leading to a higher AAR. Although higher AAR is often used as a surrogate measure of advanced fibrosis, advancing age can also contribute to increased AAR. In fact, an AAR ≥ 1 was found in significant number of elderly patients without advanced fibrosis. Consequently, an increased AAR may be a function of decreasing ALT with age in addition to progressive fibrosis.

Incidence of non-alcoholic fatty liver disease in Hong Kong: a population study with paired proton-magnetic resonance spectroscopy

BACKGROUND & AIMS

Because abdominal ultrasonography cannot reliably quantify hepatic steatosis, accurate data on the incidence of non-alcoholic fatty liver disease (NAFLD) are lacking. We aimed to study the population incidence of NAFLD with state-of-the-art non-invasive tests.

METHODS

This was a prospective cohort study. The intrahepatic triglyceride (IHTG) content was measured serially with proton-magnetic resonance spectroscopy in community subjects. Transient elastography was performed to assess liver fibrosis.

RESULTS

565 subjects (mean age 48 years, 62.7% women) without NAFLD at baseline underwent follow-up assessment after a median interval of 47 months (range 34-60 months). 78 (13.8%) subjects developed incident fatty liver with a mean IHTG content of 8.9% (SD 5.3%). 16 (20.5%) subjects had an IHTG content ⩾ 11.0% suggestive of moderate to severe steatosis. After excluding 2 men with significant alcohol consumption, the population incidence of NAFLD at 3-5 years was 13.5% (95% CI 10.6-16.3%; 3.4% per year). Only 1 subject with incident NAFLD had high liver stiffness (11.1 kPa) suggestive of advanced fibrosis. Metabolic syndrome at baseline was the strongest predictor of incident fatty liver. Incident central obesity developed in 31.0% of subjects with incident fatty liver and 5.6% of those without (p<0.001). No subject with incident fatty liver had regression of impaired fasting glucose, which occurred in 51.1% of those without incident fatty liver (p=0.001).

CONCLUSIONS

13.5% of the Hong Kong Chinese adult population develop NAFLD in 3-5 years, but few have severe steatosis or advanced fibrosis. Metabolic syndrome is the most important risk factor of incident NAFLD.

Nonalcoholic fatty liver disease is underrecognized in the primary care setting

OBJECTIVES

The prevalence and disease burden of nonalcoholic fatty liver disease (NAFLD) are increasing. Nonetheless, little is known about the processes related to identification, diagnosis, and referral of patients with NAFLD in routine clinical care.

METHODS

Using automated data, we isolated a random sample of patients in a Veterans Administration facility who had ≥2 alanine transaminase (ALT) values >40 IU/ml >6 months apart in the absence of any positive results for hepatitis C RNA, hepatitis B surface antigen, or screens for excess alcohol use. We conducted a structured medical record review to confirm NAFLD and abstracted data from the primary care providers' notes for (i) recognition of abnormal ALT levels, (ii) mention of NAFLD as a possible diagnosis, (iii) recommendations for diet or exercise, and (d) referral to a specialist for further NAFLD evaluation. Using a multilevel logistic regression model, we identified patient demographic, clinical, comorbidity, and health-care utilization factors associated with recognition and receipt of early NAFLD care.

RESULTS

Of 251 patients identified with NAFLD by our methods, 99 (39.4%) had documentation in medical record notes of abnormal ALT, 54 (21.5%) had NAFLD mentioned as a possible diagnosis, 37 (14.7%) were counseled regarding diet and exercise, and 26 (10.4%) were referred to a specialist. Only the magnitude of ALT elevation (adjusted odds ratio (OR) for ALT >80 IU/ml vs. <80 IU/ml=4.4, 95% confidence interval (CI)=2.65-7.30) and proportion of elevation (adjusted OR for >50% vs. <50% of ALT values >40 IU/ml=1.8, 95% CI=1.03-3.14) were associated with receiving specified NAFLD care. Only 3% of patients at a high risk of fibrosis (NAFLD fibrosis score >0.675) were referred to specialists.

CONCLUSIONS

Most patients in care who may have NAFLD are not being recognized and evaluated for this condition. Our data suggest that providers may be using an incorrect heuristic in delivering NAFLD care by concentrating on those with high ALT levels.

Upper limit of normal serum alanine aminotransferase levels in Japanese subjects

AIM

Serum alanine aminotransferase (ALT) is important for screening, diagnosis and management of chronic liver diseases. The incidence of non-alcoholic fatty liver disease (NAFLD)/non-alcoholic steatohepatitis (NASH), which is considered a hepatic manifestation of lifestyle-related diseases, is increasing worldwide. However, the upper limit of the normal ALT level has not yet been established because of not excluding many lifestyle-related diseases. The aim of this study was to evaluate the upper limit of normal serum ALT levels in Japanese subjects.

METHODS

We analyzed the serum ALT levels of 11 404 Japanese subjects negative for hepatitis B surface antigen and hepatitis C virus antibody, and who received health check-ups. Lifestyle factors related to ALT levels were determined by multivariate analysis. Subjects with all factors identified by multivariate analysis within the normal range were defined as "healthy" subjects. The 90th percentile of ALT levels in healthy subjects was defined as the upper limit of normal ALT.

RESULTS

Whereas alcohol intake was not a significant factor, the following were independently associated with ALT concentration by multivariate analysis: sex; age; body mass index; waist circumference; concentrations of total cholesterol, high-density lipoprotein cholesterol, triglycerides and fasting blood glucose; and fatty liver on ultrasonography. Healthy subjects consisted of 1462 (21.2%) men and 2046 (45.4%) women, and the 90th percentiles of the ALT levels in the two groups were 29 and 23 IU/L, respectively.

CONCLUSION

The upper limits of normal ALT when considering lifestyle factors in Japanese subjects were 29 IU/L in men and 23 IU/L in women.

Clinical, anthropometric, biochemical, and histological characteristics of nonobese nonalcoholic fatty liver disease patients of Bangladesh

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is considered to be a disease of obese individuals, yet lean patients are increasingly susceptible to have NAFLD. The aim of this study was to evaluate the profile of nonobese patients by comparing with obese NAFLD patients.

METHODS

We have included 465 patients of NAFLD after exclusion of other diseases, and 220 with elevated alanine aminotransferase (ALT) were biopsied. Patients were biochemically and clinically evaluated: blood pressure, body mass index (BMI), and waist circumference (WC) were recorded for every patient. A BMI  ≥ 25 kg/m(2) was defined as obese, and those with a BMI of <25 kg/m(2) were labeled as nonobese. Histological activity was expressed with NAFLD activity score (NAS).

RESULTS

Of 465 cases, 119 (25.6 %) were nonobese. Diabetes was noted in 122 (26.2 %) and hypertension in 122 (26.2 %). Metabolic syndrome was present in 253 (59.7 %), low HDL cholesterol in 228 (64.8 %), hypertriglyceridemia in 297 (73.2 %), and WC above normal in 308 (70.2 %). Males were predominating in the nonobese compared to females in the obese (p = 0.001). Hypertriglyceridemia and low high-density lipoprotein was similar in the obese and nonobese (76.2 % vs. 72.3 %, p = 0.5 and 65.2 % vs. 64.6 %, p = 1.0, respectively). The grades of steatosis, lobular inflammation, ballooning, NAS, and the stage of fibrosis did not also significantly differ between obese and nonobese patients. Nonalcoholic steatohepatitis (NASH) was 53.1 % in nonobese.

CONCLUSION

Nonobese was 25.6 % among NAFLD patients of Bangladesh, and 53.1 % of nonobese NAFLD cases were NASH. Though they were nonobese by BMI grade, they were metabolically similar to obese. Males were predominant in the nonobese, whereas females in the obese. NASH and fibrosis were similar in the obese and nonobese.

Systematic review with meta-analysis: non-invasive assessment of non-alcoholic fatty liver disease--the role of transient elastography and plasma cytokeratin-18 fragments

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) affects 15-40% of the general population. Some patients have non-alcoholic steatohepatitis (NASH) and progressive fibrosis, and would be candidates for monitoring and treatment.

AIM

To review current literature on the use of non-invasive tests to assess the severity of NAFLD.

METHODS

Systematic literature searching identified studies evaluating non-invasive tests of NASH and fibrosis using liver biopsy as the reference standard. Meta-analysis was performed for areas with adequate number of publications.

RESULTS

Serum tests and physical measurements like transient elastography (TE) have high negative predictive value (NPV) in excluding advanced fibrosis in NAFLD patients. The NAFLD fibrosis score comprises of six routine clinical parameters and has been endorsed by current American guidelines as a screening test to exclude low-risk individuals. The pooled sensitivities and specificities for TE to diagnose F ≥ 2, F ≥ 3 and F4 disease were 79% and 75%, 85% and 85%, and 92% and 92% respectively. Liver stiffness measurement often fails in obese patients, but the success rate can be improved with the use of the XL probe. A number of biomarkers have been developed for the diagnosis of NASH, but few were independently validated. Serum/plasma cytokeratin-18 fragments have been most extensively evaluated and have a pooled sensitivity of 66% and specificity of 82% in diagnosing NASH.

CONCLUSIONS

Current non-invasive tests are accurate in excluding advanced fibrosis in NAFLD patients, and may be used for initial assessment. Further development and evaluation of NASH biomarkers are needed.

Comparison of characteristics between nonobese and overweight/obese subjects with nonalcoholic fatty liver disease in a South Indian population

AIMS

This study was designed to compare the characteristics of nonobese and overweight/obese subjects with nonalcoholic fatty liver disease (NAFLD) in an urban South Indian population.

SUBJECTS AND METHODS

The study group comprises 541 subjects drawn from the Chennai Urban Rural Epidemiology Study (CURES), which was carried out on a representative sample of Chennai city in southern India. NAFLD was diagnosed by ultrasonography. Subjects with NAFLD were classified as nonobese (body mass index of ≤22.9 kg/m(2)) and overweight/obese (body mass index of ≥23 kg/m(2)) based on World Health Organization Asia Pacific guidelines. Coronary artery disease (CAD) was assessed by a resting 12-lead electrocardiogram that was Minnesota-coded. Insulin resistance was assessed by using the homeostasis assessment model (HOMA-IR) using the following formula: fasting insulin (μIU/mL)×fasting glucose (mmol/L)/22.5.

RESULTS

In total, 173 of 541 (32%) subjects had NAFLD, of whom 48 (27.7%) had nonobese NAFLD and 125 (72.3%) had overweight/obese NAFLD. Compared with overweight/obese NAFLD patients, fasting blood glucose (104±29 vs. 119±45 mg/dL; P<0.05) and HOMA-IR (2.1±1.8 vs. 2.9±1.8; P<0.001) were lower and high-density lipoprotein cholesterol (43±9 vs. 39±8 mg/dL; P<0.001) was higher among nonobese NAFLD subjects. Multiple logistic regression analysis showed a significant association between nonobese NAFLD and CAD (P=0.013) even after adjusting for age, diabetes, hypercholesterolemia, HOMA-IR, and hypertension.

CONCLUSIONS

This study suggests that even nonobese NAFLD subjects have an association with CAD.

Predictive value of ALT levels for non-alcoholic steatohepatitis (NASH) and advanced fibrosis in non-alcoholic fatty liver disease (NAFLD)

BACKGROUND

Non-alcoholic fatty liver disease (NAFLD) patients with elevated serum alanine aminotransferase (ALT) generally undergo a liver biopsy to evaluate for possible non-alcoholic steatohepatitis (NASH) or advanced fibrosis. However, patients with normal ALT could also have advanced stages of NAFLD.

AIM

To determine ALT value that will accurately predict NASH and advanced fibrosis using area under the receiver operating characteristics curve (AUROC) analysis.

METHODS

Demographic, clinical and laboratory data of an ethnically diverse cohort of biopsy proven NAFLD patients were retrospectively analysed under univariate and multivariate analyses. Liver biopsies were scored using NASH clinical research network (NASH CRN) system. AUROC were performed for NAFLD Activity Score ≥5 (NASH) and fibrosis score ≥2 (advanced fibrosis).

RESULTS

Two hundred and twenty-two patients were analysed. Fifty six (23%) had normal ALT. There was no difference in the rate of advanced fibrosis between normal and elevated ALT (26.8% vs. 18.1%, P = 0.19). However, significantly lower percentage of normal ALT group had NASH compared with elevated ALT group (10.7% vs. 28.9%, P < 0.01). Overall, 37.5% of normal ALT group had NASH or advanced fibrosis, whereas 53% of elevated ALT had no NASH or advanced fibrosis. Higher ALT values correlated with higher specificity, but lower sensitivity for both NASH and advanced fibrosis. AUROC for ALT level correlating NASH and advanced fibrosis were 0.62 and 0.46 respectively.

CONCLUSION

There is no optimal ALT level to predict NASH and advanced fibrosis. Metabolic risk factors should be evaluated to select patients for a liver biopsy to confirm NASH and advanced fibrosis.

Community-based lifestyle modification programme for non-alcoholic fatty liver disease: a randomized controlled trial

BACKGROUND & AIMS

Healthy lifestyle is the most important management of non-alcoholic fatty liver disease (NAFLD). This study aimed at assessing the efficacy of a community-based lifestyle modification programme in the remission of NAFLD.

METHODS

This was a parallel group, superiority, randomized controlled trial. 154 adults with NAFLD identified during population screening were randomized to participate in a dietitian-led lifestyle modification programme at 2 community centres or receive usual care for 12 months. The primary outcome was remission of NAFLD at month 12 as evidenced by intrahepatic triglyceride content (IHTG) of less than 5% by proton-magnetic resonance spectroscopy.

RESULTS

74 patients in the intervention group and 71 patients in the control group completed all study assessments. In an intention-to-treat analysis of all 154 patients, 64% of the patients in the intervention group and 20% in the control group achieved remission of NAFLD (difference between groups 44%; 95% CI 30-58%; p<0.001). The mean (SD) changes in IHTG from baseline to month 12 were -6.7% (6.1%) in the intervention group and -2.1% (6.4%) in the control group (p<0.001). Body weight decreased by 5.6 (4.4) kg and 0.6 (2.5) kg in the two groups, respectively (p<0.001). While 97% of patients with weight loss of more than 10% had remission of NAFLD, 41% of those with weight loss of 3.0-4.9% could also achieve the primary outcome.

CONCLUSIONS

The community-based lifestyle modification programme is effective in reducing and normalizing liver fat in NAFLD patients.

Epidemiology of alcoholic and nonalcoholic fatty liver disease in China

The prevalence of patients presenting with fatty liver disease (FLD) in China has approximately doubled over the past two decades. At present, FLD, which is typically diagnosed by imaging, is highly prevalent (≈ 27% urban population) in China and is mainly related to obesity and metabolic syndrome (MetS). However, the percentage of alcoholic liver disease (ALD) among patients with chronic liver diseases in clinic is increasing as well, and a synergetic effect exists between heavy alcohol drinking and obesity in ALD. Prevalence figures reveal regional variations, with a median prevalence of ALD and nonalcoholic FLD (NAFLD) of 4.5% and 15.0%, respectively. The prevalence of NAFLD in children is 2.1%, although the prevalence increases to 68.2% among obese children. With the increasing pandemic of obesity and MetS in the general population, China is likely to harbor an increasing reservoir of patients with FLD. The risk factors for FLD resemble to those of Caucasian counterparts, but the ethnic-specific definitions of obesity and MetS are more useful in assessment of Chinese people. Therefore, FLD/NAFLD has become a most common chronic liver disease in China. Public health interventions are needed to halt the worldwide trend of obesity and alcohol abuse to ameliorate liver injury and to improve metabolic health.

Obesity, insulin resistance, NASH and hepatocellular carcinoma

Epidemiological and clinical data have clearly demonstrated that non-alcoholic steatohepatitis (NASH) predisposes risk to the development of hepatocellular carcinoma (HCC). NASH is the liver manifestation of metabolic syndrome, which constellates obesity, insulin resistance and dyslipidemia. Although the percentage of patients diagnosed annually with NASH-associated HCC is still relatively low, this number signifies a large population due to the rapidly increasing incidence of obesity and diabetes globally. Fundamental studies on lipid storage, regulation of adipose factors, inflammatory cytokine recruitments and oxidative stress have provided insights into NASH as well as metabolic syndrome. Recent evidence also indicates the significant role of genetic factors in contributing to the pathogenesis of NASH and induced hepatic malignancy. In this review, we attempt to collate current research on NASH biology that lead to our understandings on how metabolic disorders may intersect with cancer development. We also discuss study models that have supported discoveries of molecular and cellular defects, and offered a perspective on therapeutic developments. These studies have collectively increased our knowledge on the complex signaling pathways involved in NASH and cancer, and provided the foundation for improved clinical management of patients with metabolic diseases.

Vitamin E and changes in serum alanine aminotransferase levels in patients with non-alcoholic steatohepatitis

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a common cause of serum alanine aminotransferase (ALT) elevations and chronic liver disease, but it is unclear how well ALT elevations reflect the liver injury.

AIM

To assess how well changes in ALT elevations reflect improvements in liver histology in response to vitamin E therapy.

METHODS

The vitamin E and placebo arms of the Pioglitazone vs. Vitamin E vs. Placebo in Non-alcoholic Steatohepatitis (PIVENS) trial were reassessed for associations among changes in ALT levels, body weight and liver histology. An ALT response was defined as a decrease to ≤40 U/L and by ≥30% of baseline. Liver biopsies taken before and after treatment were scored for non-alcoholic fatty liver disease activity (NAS) and fibrosis.

RESULTS

ALT responses were more frequent among vitamin E (48%) than placebo (16%) recipients (P < 0.001). Among vitamin E recipients, ALT responses were associated with decreases in NAS (P < 0.001), but not fibrosis scores (P = 0.34), whereas among placebo recipients, ALT responses were associated with significant decreases in both (P < 0.05). Weight loss (≥2 kg) was also associated with ALT response (P < 0.001), improvements in NAS (P < 0.001) and fibrosis (P < 0.02), but vitamin E had an added effect both with and without weight loss. Weight gain (≥2 kg) was associated with lack of ALT response and worsening NAS and fibrosis scores in patients not on vitamin E.

CONCLUSIONS

Decrease of ALT levels to normal in patients with NASH is usually associated with improved histological activity. Management should stress the value of weight loss and strongly discourage weight gain. Vitamin E can improve both ALT levels and histology with and without weight loss.

CLINICAL TRIAL NUMBER

NCT00063622.

Are simple noninvasive scoring systems for fibrosis reliable in patients with NAFLD and normal ALT levels?

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is common and many affected individuals have normal-range alanine aminotransferase (ALT) levels. There is a need for a robust screening tool to triage individuals with advanced fibrosis for specialist care.

AIM

The aim of this study was to assess the performance of noninvasive fibrosis tests in patients with biopsy-proven NAFLD and normal levels of ALT.

METHODS

Patients presenting at a fatty liver clinic between 1999 and 2009 were included in the study. Liver biopsies were assessed using the Kleiner score. The aspartate aminotransferase (AST)/ALT ratio, BARD, FIB-4 and NAFLD fibrosis scores were calculated.

RESULTS

A total of 305 patients were included [70 with normal ALT levels (women: ALT≤30 IU/l, men: ALT≤45 IU/l) and 235 with elevated levels]. In total, 24% of patients with normal ALT levels and 17% of those with elevated ALT levels had advanced fibrosis (Kleiner stage 3-4). The FIB-4 performed best in identifying advanced fibrosis in patients with normal ALT (area under receiver operating characteristic curve=0.86, 82% sensitivity, 77% specificity and 92% negative predictive value). The sensitivity of the AST/ALT ratio and BARD and NAFLD fibrosis scores for advanced fibrosis was good in patients with normal ALT levels (94, 94 and 82%, respectively), but the specificity was low (44, 26 and 51%, respectively). The FIB-4 yielded best results in patients with elevated ALT levels. Using the FIB-4, 61% of patients with normal ALT levels and 63% of those with elevated ALT levels could avoid liver biopsy to exclude advanced fibrosis. In contrast, AST/ALT ratio and BARD and NAFLD scores would have led to a high proportion of patients with mild disease having to undergo a biopsy.

CONCLUSION

The FIB-4 yielded good results in patients with normal or elevated ALT levels, reliably excluding advanced fibrosis and reducing the need for liver biopsy.

Upper limit of normal for alanine aminotransferase: quo vadis?

Several studies suggest that a substantial number of patients with normal serum alanine aminotransferase (ALT) levels, defined by current thresholds, have ongoing hepatic necro-inflammation and fibrosis, and are at risk of liver disease progression. A major problem lies in the definition of normality. The current upper limit of normal (ULN) for ALT was established in the 1980s when reference populations were likely to include many persons with hepatitis C virus infection and nonalcoholic fatty liver disease. Because ALT may be influenced, not only by liver disease, but also by other medical conditions, changing lifestyle factors and demographic determinants, the current ALT ULN threshold has recently been challenged. This review not only highlights current evidence on why and how ALT ULN should be redefined, but also discusses the current concerns about updating the ULN threshold for ALT.

The severity of histologic liver lesions is independent of body mass index in patients with nonalcoholic fatty liver disease

GOALS/BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) is associated with obesity, but it may also be present in lean individuals. We evaluated the characteristics of NAFLD patients, focusing on those with normal body mass index (BMI).

STUDY

One hundred and sixty-two of 185 consecutive NAFLD patients were included. Demographic, clinical, somatometric, and laboratory characteristics were recorded. BMI<25 kg/m2 was considered to be normal.

RESULTS

Of the 162 patients, 12% had normal BMI. Patients with normal compared with those with increased BMI fulfilled more frequently no criterion of metabolic syndrome (43% vs. 2%; P<0.001) and had higher median alanine aminotransferase (92 vs. 62 IU/L; P=0.032) and aspartate aminotransferase levels (45 vs. 37 IU/L; P=0.036). Liver stiffness values by transient elastography were significantly lower in patients with normal than in those with increased BMI (5.0 ± 1.6 vs. 9.5 ± 8.7 kPa; P=0.003). In the 56 patients with liver biopsy, the prevalence of nonalcoholic steatohepatitis (50% vs. 68.8%; P=0.423) and the severity of inflammation and fibrosis did not significantly differ between cases with normal and those with increased BMI.

CONCLUSIONS

Approximately 1 of 8 NAFLD patients coming to a Greek tertiary liver center has normal BMI. On liver biopsy, normal BMI patients often have nonalcoholic steatohepatitis and histologic liver lesions of similar severity to the overweight or obese patients.

Nonalcoholic fatty liver disease in Asia: a story of growth

Ten years ago, few if any researchers in Asia showed interest in nonalcoholic fatty liver disease (NAFLD). Today, NAFLD is increasingly recognized as a major chronic liver disease not only in Western countries but also in Asia. Its importance is exemplified by its high prevalence, disease progression, and association with major medical disorders. In Asia, 15-30% of the general adult population suffers from NAFLD. In patients with diabetes and metabolic syndrome, the reported prevalence is typically over 50%. Patients with the active form of NAFLD, namely steatohepatitis (NASH), may have fibrosis progression and eventually develop cirrhosis. Patients with NASH-related cirrhosis have similar mortality to those with other causes of cirrhosis, and they have a high risk of developing hepatocellular carcinoma up to 2-3% per year. In addition, NAFLD patients have a high prevalence of cardiovascular disease and colorectal neoplasm. One major challenge for practicing clinicians is how to identify patients with significant liver disease among many who are found to have NAFLD. While liver biopsy is traditionally considered the gold standard for disease staging, it is invasive and unpleasant, and is an impractical tool for a disease that affects a quarter of the general population. To this end, new developments in transient elastography and biomarkers such as cytokeratin-18 fragments can help exclude significant liver fibrosis and NASH, respectively. This article summarizes a young researcher's journey through this exciting area of research and what he has learned from amazing people all around the world.

Upper limits of normal for serum alanine aminotransferase levels in Chinese Han population

BACKGROUND AND OBJECTIVES

Serum alanine aminotransferase (ALT) activity is the most common tool for the assessment of liver diseases. However, it is not clear whether the current normal ALT range really discriminate patients with or without liver diseases. The present study was to establish a new normal range of ALT and examine its ability to identify patients with hepatitis B or nonalcoholic fatty liver disease (NAFLD) in Chinese Han population.

METHODS

53037 adults were included in this study from January 1st 2008 to August 31st 2010. The 95th percentile of ALT in population with relative low risk factors for liver diseases was set as the new upper limits of normal ALT in gender-specific manner.

RESULTS

The 95(th) percentile levels at low risk factors for liver diseases were achieved at 35 U/L for men and 23 U/L for women. The concordance statistics for detection were 0.873 (95%CI: 0.865-0.881) for HBV and 0.932 (95%CI: 0.927-0.937) for NAFLD in men while 0.857 (95%CI: 0.850-0.864) for HBV and 0.909 (95%CI: 0.903-0.915) for NAFLD in women. The median sensitivity of the current used ALT upper limit (40 U/L) was 6.6% for HBV and 29.7% for NAFLD and median specificity was 98.7% for men and 99.4% for women. Using our new-derived thresholds, the sensitivities ranged from 35.3% to 61.1% and the specificities were 94.8% for men and 94.6% for women.

CONCLUSIONS

Our results suggest that upper limits of ALT 35 U/L for men and 23 U/L for women in Chinese Han population. Re-consideration of normal limits of ALT should be recommended.

TRIAL REGISTRATION

ChiCTR.org ChiCTR-OCS-11001173.

Non-alcoholic Fatty Liver Disease: East Versus West

Non-alcoholic fatty liver disease (NAFLD) is an important cause of liver disease worldwide with prevalence ranging from 10% to 30% in various countries. It has become an important cause of unexplained rise in transaminases, cryptogenic cirrhosis, and cryptogenic hepatocellular carcinoma. Pathogenesis is related to obesity, insulin resistance, oxidative stress, lipotoxicity, and resultant inflammation in the liver progressing to fibrosis. Pharmacological treatment in patients with NAFLD is still evolving and the treatment of these patients rests upon lifestyle modification with diet and exercise being the cornerstones of therapy. While there are many similarities between patients with NAFLD from Asia and the West, there are certain features which make the patients with NAFLD from Asia stand apart. This review highlights the data on NAFLD from Asia comparing it with the data from the West.

Nonalcoholic fatty liver disease: a review of the spectrum of disease, diagnosis, and therapy

Worldwide, there is an epidemic of obesity and overweight, with two-thirds of Americans affected. A strong association exists between excessive body weight and nonalcoholic fatty liver disease (NAFLD), the most common etiology of abnormal liver function tests. Nonalcoholic fatty liver disease is a spectrum of liver disease, from a "bland" fatty infiltration to chronic hepatitis (nonalcoholic steatohepatitis or NASH), that can result in cirrhosis and organ failure. With the increasing prevalence of obesity in the world, the proportion of people affected by NAFLD is only expected to be parallel. Although primarily noted in obese individuals, NAFLD has also been associated with a number of surgical procedures, metabolic conditions, and medications. NASH is commonly underdiagnosed as most affected patients are symptom free, and routine screening is not performed. Noninvasive diagnostic testing is not sensitive in diagnosis or staging the severity of disease. Fatty infiltration and oxidative injury to the hepatocytes are believed to be the major factors behind the progression of disease from simple fatty infiltration of the liver to chronic hepatitis. Understanding the inflammatory pathways involved in NASH is a subject of extensive research. Currently, few proven treatment options exist, and controlled weight reduction is the only safe modality recommended for treatment of NASH.

Serum concentrations of insulin-like growth factor-I, insulin-like growth factor binding protein-3 and cardiovascular risk factors in adolescents

BACKGROUND

The risk association between the insulin like growth factor-I (IGF-I) system and cardiovascular risk is inconclusive in adults and under-explored in adolescents. We aimed to investigate the associations between serum concentrations of IGF-I and IGF binding protein-3 (IGFBP-3) and cardiovascular risk factors in adolescents.

METHODS

This was a cross-sectional, population-based, observational study in a school setting with 2102 Hong Kong Chinese adolescents aged 12-19 years. Serum IGF-I and IGFBP-3 concentrations were measured by chemiluminescence immunoassays. Anthropometric indices and traditional cardiovascular risk factors were assessed.

RESULTS

After excluding participants with abnormal thyroid and liver test results, 765 boys and 877 girls, mean (±SD) age of 15.3 (±2.0) and 15.7 (±2.0) years, respectively, were included in the analysis. Multivariable regression analyses revealed that both IGF-I and IGFBP-3 concentrations were independently associated with waist circumference, fasting insulin and haemoglobin concentrations in boys (all P < 0.05), systolic blood pressure, serum creatinine, fasting insulin and haemoglobin concentrations in girls (all P < 0.05). In girls, IGF-I was also associated with C-reactive protein concentration (P < 0.001) and IGFBP-3 was associated with fasting triglyceride concentration (P < 0.001). Compared with adolescents with the lowest tertile, the top tertile of both IGF-I and IGFBP-3 concentrations were associated with increased odds of having overweight/obesity, top tertiles of insulin and haemoglobin in both boys and girls (P for trend, all <0.05).

CONCLUSIONS

The associations between serum IGF-I, IGFBP-3, obesity, cardiovascular risk factors, insulin and haemoglobin suggest that dysregulation of the IGF system may play a linking role for the clustering of cardiovascular risk factors.

Non-alcoholic fatty liver disease's prevalence and impact on alanine aminotransferase associated with metabolic syndrome in the Chinese

BACKGROUND AND AIM

Non-alcoholic fatty liver disease (NAFLD) is becoming a major public health hazard in China. The present study aimed to estimate the prevalence of NAFLD, NAFLD with abnormal serum alanine aminotransferase (ALT) levels, and determine the potential associations of ALT levels with the components of metabolic syndrome (MetS) in the absence or presence of NAFLD in Chinese adults.

METHODS

A population-based cross-sectional survey was conducted with 2226 participants. Physical examinations, laboratory tests and hepatic ultrasounds were performed. Individuals were further stratified into higher or lower ALT subgroups with the upper quartiles of ALT in this population. The MetS was identified according to the criteria of the Chinese Joint Committee for Developing Chinese Guidelines (JCDCG).

RESULTS

The standardized prevalence of NAFLD was 23.3% (NAFLD with abnormal ALT levels, 3.1%), 26.5% (NAFLD with abnormal ALT levels, 5.1%) in males, and 19.7% (NAFLD with abnormal ALT levels, 0.9%) in females. Multivariate logistic analysis revealed that higher ALT was significantly associated with elevated triglyceride (TG) in the non-NAFLD participants, independent of age, smoking status, drinking status, and other MetS-related measures with odds ratios (95% confidence intervals) of 3.4 (1.6-7.1) and 2.3 (1.4-3.7) in males and females, respectively. On the other hand, the higher ALT was statistically associated with elevated TG and hyperglycemia in the NAFLD cases with odds ratios of 2.2 to 2.5 (P<0.05).

CONCLUSIONS

The prevalence of NAFLD has become epidemic in Shanghai adults. NAFLD combined with ALT levels may be used to identify the individuals at the different risk levels of metabolic disorders.

Healthy range for serum ALT and the clinical significance of "unhealthy" normal ALT levels in the Korean population

BACKGROUND AND AIMS

It remains unclear whether the currently-used normal range for serum alanine aminotransferase (ALT) levels really reflects a healthy liver. The present study was conducted to evaluate the healthy range of serum ALT in the Korean adult population and to determine the clinical significance of unhealthy levels.

METHODS

We reviewed the medical records, including questionnaires and the results of laboratory and radiological tests conducted at the Health Promotion Center at Korea University Anam Hospital between March 2005 and February 2007. The records, written in questionnaire form, included baseline data, such as physical status, social behaviors, medication history, and past and present disease histories.

RESULTS

The mean age of the 7403 enrolled patients was 48 years, and 49.9% of these patients were male. A healthy cohort was selected after excluding patients who showed any abnormalities of the factors that were significantly associated with the serum ALT level upon multivariate regression analysis. The upper limit of the healthy range of the serum ALT level (i.e. 95th percentile) in the healthy population was 31 IU/L for males and 23 IU/L for females. The prevalence of metabolic syndrome and insulin resistance (IR) were significantly higher in patients with an 'unhealthy' normal ALT level than in those with a healthy ALT level.

CONCLUSION

In our study, the upper limit of the healthy range of the serum ALT level was 31 IU/L for males and 23 IU/L for females. An unhealthy normal ALT level was associated with a higher prevalence of metabolic syndrome and IR.

Nonalcoholic fatty liver in Asia: Firmly entrenched and rapidly gaining ground

Nonalcoholic fatty liver disease (NAFLD) is becoming an important chronic liver disorder in Asia. Prevalence figures show regional variations but at least 10% of the general population in Asia have fatty liver. Fatty liver can develop with relatively small changes in weight (2-3 kg), often with increasing central adiposity. The metabolic syndrome may precede or follow NAFLD. Overt diabetes is present in one-third of cases but when oral glucose tolerance tests are performed, a further third of individuals have impaired glucose tolerance or diabetes. Natural history data are still scarce but cases of advanced hepatic fibrosis and hepatocellular carcinoma are now regularly reported. Many cases of cryptogenic cirrhosis are also attributable to NAFLD. Histological progression has been demonstrated for patients with NASH as well as for those with hepatic steatosis alone. Genetic factors may in part contribute to the rise in NAFLD. Polymorphisms within apolipoprotein C3 (APOC3) gene have been linked to NAFLD in lean Indian men. Although a number of other polymorphisms involving genes controlling adipose distribution, insulin signalling, adipokine responses and hepatic fibrosis have been reported, these studies have been underpowered. Transient elastography could help in detecting and monitoring hepatic fibrosis but further refinements in technique are necessary for obese individuals. Of the biomarkers, hyaluronic acid and cytokeratin-18 fragment testing show promise as markers of hepatic fibrosis and NASH, respectively. Lifestyle alterations including dietary changes and increased physical activity remain the cornerstone of management. Attention should be paid to prevention through public education of campaigns addressing the increase in both adult and childhood obesity.

Intracellular nicotinamide phosphoribosyltransferase protects against hepatocyte apoptosis and is down-regulated in nonalcoholic fatty liver disease

CONTEXT

Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in Western and non-Western countries, but its pathogenesis is not fully understood.

OBJECTIVE

Based on the role of nicotinamide phosphoribosyltransferase (NAMPT) in fat and glucose metabolism and cell survival, we hypothesized a role for NAMPT/visfatin in the pathogenesis of NAFLD-related disease.

DESIGN AND SETTING

We conducted clinical studies at a referral medical center in well-characterized NAFLD patients (n = 58) and healthy controls (n = 27). In addition we performed experimental in vitro studies in hepatocytes.

MAIN OUTCOME MEASURES

We examined 1) the hepatic and systemic expression of NAMPT/visfatin in patients with NAFLD and control subjects, 2) the hepatic regulation of NAMPT/visfatin, and 3) the effect of NAMPT/visfatin on hepatocyte apoptosis.

RESULTS

Our main findings were as follows. 1) Patients with NAFLD had decreased NAMPT/visfatin expression both systemically in serum and within the hepatic tissue, with no difference between simple steatosis and nonalcoholic steatohepatitis. 2) By studying the hepatic regulation of NAMPT/visfatin in wild-type and peroxisome proliferators-activated receptor (PPAR)alpha(-/-) mice as well as in hepatocytes, we showed that PPARalpha activation and glucose may be involved in the down-regulation of hepatic NAMPT/visfatin expression in NAFLD. 4) Within the liver, NAMPT/visfatin was located to hepatocytes, and our in vitro studies showed that NAMPT/visfatin exerts antiapoptotic effects in these cells, involving enzymatic synthesis of nicotinamide adenine dinucleotide.

CONCLUSION

Based on these findings, we suggest a role for decreased NAMPT/visfatin levels in hepatocyte apoptosis in NAFLD-related disease.

A human-type nonalcoholic steatohepatitis model with advanced fibrosis in rabbits

Nonalcoholic steatohepatitis (NASH) progresses to liver fibrosis and cirrhosis, which can lead to life-threatening liver failure and the development of hepatocellular carcinoma. The aim of the present study was to create a rabbit model of NASH with advanced fibrosis (almost cirrhosis) by feeding the animals a diet supplemented with 0.75% cholesterol and 12% corn oil. After 9 months of feeding with this diet, the rabbits showed high total cholesterol levels in serum and liver tissues in the absence of insulin resistance. The livers became whitish and nodular. In addition, the number of rabbit macrophage antigen-positive cells and the expression of mRNAs for inflammatory cytokines showed a significant increase. Moreover, fibrotic septa composed of collagens and alpha-smooth muscle actin-positive cells were found between the central and portal veins, indicating alteration of the parenchymal architecture. There was also a marked increase of mRNAs for transforming growth factor-beta1 and collagen 1A1. Comprehensive analysis of protein and gene expression revealed an imbalance of the antioxidant system and methionine metabolism. We also found that ezetimibe attenuated steatohepatitis in this model. In conclusion, the present rabbit model of NASH features advanced fibrosis that is close to cirrhosis and may be useful for analyzing the molecular mechanisms of human NASH. Ezetimibe blunted the development of NASH in this model, suggesting its potential clinical usefulness for human steatohepatitis.

Visceral adipose tissue and inflammation correlate with elevated liver tests in a cohort of overweight and obese patients

OBJECTIVE

To study the relationship between elevated liver tests and high sensitive C-reactive protein (hs-CRP), as potential markers of liver inflammation and non-alcoholic steatohepatitis (NASH), with anthropometric and laboratory parameters in overweight patients, especially the relationship with visceral adipose tissue (VAT).

METHODS

Patients presenting to the obesity clinic were prospectively included. Detailed anthropometry, computed tomography (CT)-measured VAT, liver tests (aspartate transaminase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP) and gamma-glutamyl transferase (GGT)) and hs-CRP were assessed, along with an extended series of biochemical parameters.

RESULTS

All 480 patients (gender distribution male (M)/female (F) (10/90%)) with complete data were included. Mean age was 39+/-13 years, mean BMI 34.5+/-6.0 kg m(-2). In 37.3% of the patients one or more of the liver tests were elevated. VAT was positively related to AST (r=0.18, P<0.001), ALT (r=0.29, P<0.001), ALP (r=0.16, P<0.01) and GGT (r=0.39, P<0.001). Comparing subjects with high (VAT>or=113 cm(2)) vs low (VAT<113 cm(2)) VAT levels, significant differences were noted for AST (26+/-12 vs 24+/-12 U l(-1), P=0.003), ALT (37+/-21 vs 31+/-21 U l(-1), P<0.001), ALP (76+/-20 vs 71+/-18 U l(-1), P=0.008), GGT (33+/-20 vs 25+/-15 U l(-1), P<0.001) and hs-CRP (0.62+/-0.43 vs 0.52+/-0.48 mg dl(-1), P<0.001). After correction for BMI the difference in AST and ALP between the high vs low VAT group disappeared. The differences for ALT and GGT remained significant (P=0.008 and P<0.001 respectively). After correction for hs-CRP the four different liver tests remained significantly higher in the high VAT group. A stepwise multiple regression analysis revealed that every single liver test has his own most important determinant; VAT and hs-CRP for AST, insulin resistance calculated with homeostasis model assessment (HOMA-IR) and hs-CRP for ALT and ALP, and triglycerides and VAT for GGT.

CONCLUSION

In overweight and obese patients, liver tests, especially ALT and GGT, are associated with visceral fat mass. After correction for BMI and hs-CRP, ALT and GGT are significantly higher in patients with increased VAT, thereby supporting evidence for a potential key role of VAT in the pathogenesis of non-alcoholic fatty liver disease (NAFLD).

Diagnosis of fibrosis and cirrhosis using liver stiffness measurement in nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in affluent countries. Accurate noninvasive tests for liver injury are urgently needed. The aim of this study was to evaluate the accuracy of transient elastography for the diagnosis of fibrosis and cirrhosis in patients with NAFLD and to study factors associated with discordance between transient elastography and histology. Two hundred forty-six consecutive patients from two ethnic groups had successful liver stiffness measurement and satisfactory liver biopsy specimens. The area under the receiver-operating characteristics curve (AUROC) of transient elastography for F3 or higher and F4 disease was 0.93 and 0.95, respectively, and was significantly higher than that of the aspartate aminotransferase-to-alanine aminotransferase ratio, aspartate aminotransferase-to-platelet ratio index, FIB-4, BARD, and NAFLD fibrosis scores (AUROC ranged from 0.62 to 0.81, P < 0.05 for all comparisons). At a cutoff value of 7.9 kPa, the sensitivity, specificity, and positive and negative predictive values for F3 or greater disease were 91%, 75%, 52%, and 97%, respectively. Liver stiffness was not affected by hepatic steatosis, necroinflammation, or body mass index. Discordance of at least two stages between transient elastography and histology was observed in 33 (13.4%) patients. By multivariate analysis, liver biopsy length less than 20 mm and F0-2 disease were associated with discordance.

CONCLUSION

Transient elastography is accurate in most NAFLD patients. Unsatisfactory liver biopsy specimens rather than transient elastography technique account for most cases of discordance. With high negative predictive value and modest positive predictive value, transient elastography is useful as a screening test to exclude advanced fibrosis. Liver biopsy may be considered in NAFLD patients with liver stiffness of at least 7.9 kPa.

Abnormal liver function tests in patients with Type 1 diabetes mellitus: prevalence, clinical correlations and underlying pathologies

AIMS

To determine the prevalence of elevated alanine transaminase (ALT) in a large cohort of patients with Type 1 diabetes and to examine the clinical correlations and causes. Methods Patients with Type 1 diabetes mellitus were prospectively recruited and ALT, glycated haemoglobin and lipid profile were measured. Patients with Type 2 diabetes mellitus were recruited as a comparison group.

PATIENTS

with abnormal ALT were investigated for underlying causes. Prevalence of abnormal ALT was analysed at three separate cut-offs and multivariable analysis used to identify independent risk factors.

RESULTS

Nine hundred and eleven with Type 1 diabetes and 963 with Type 2 diabetes were included. The prevalence of elevated ALT was dependent on the cut-off value: > 30 IU/l in males and > 19 IU/l in females, > 50 and > 63 IU/l was 34.5, 4.3 and 1.9%, respectively, in Type 1 diabetes and 51.4, 8.2 and 3.7%, respectively, in Type 2 diabetes. In Type 1 diabetes an elevated ALT was associated with worse glycaemic control, age > 55 years and elevated triglycerides. Investigation of these patients revealed a cause in 43.6% of patients, predominantly non-alcoholic fatty liver disease (NAFLD).

CONCLUSIONS

Elevated ALT is not uncommon in Type 1 diabetes and is associated with NAFLD-related risk factors. Patients with Type 1 diabetes and elevated ALT should be investigated as significant abnormalities may be found which are amenable to interventions.

The liver and the waistline: Fifty years of growth

Fifty years of the Gastroenterological Society of Australia have witnessed the changing appearance of Australians. Asian immigration has transformed the dominant urban culture from European to Eurasian, with some unique Australian attributes. Meanwhile, global conditions have altered body shape, and our sports-proud country is now fat! Thus, as in North America, Europe, China, and affluent Asia-Pacific countries, prosperity and lifestyle, cheap processed foods coupled with reduced physical activity have created an epidemic of over-nutrition resulting in overweight/obesity. Additional genetic factors are at the core of the apple shape (central obesity) that typifies over-nourished persons with metabolic syndrome. Indigenous Australians, once the leanest and fittest humans, now have exceedingly high rates of obesity and type 2 diabetes, contributing to shorter life expectancy; Asian Australians are also at higher risk. Like non-steroidal anti-inflammatory drugs (NSAIDs) and cigarette smoking, obesity now contributes much to gastrointestinal morbidity and mortality (gastroesophageal reflux disease, cancers, gallstones, endoscopy complications). This review focuses on Australian research about fatty liver, particularly roles of central obesity/insulin resistance in non-alcoholic fatty liver disease/steatohepatitis (NAFLD/NASH). The outputs include many highly cited original articles and reviews and the first book on NAFLD. Studies have identified community prevalence, clinical outcomes, association with insulin resistance, metabolic syndrome and hypoadiponectinemia, developed and explored animal models for mechanisms of inflammation and fibrosis, conceptualized etiopathogenesis, and demonstrated that NASH can be reversed by lowering body weight and increasing physical activity. The findings have led to development of regional guidelines on NAFLD, the first internationally, and should now inform daily practice of gastroenterologists.

Surrogate end points and long-term outcome in patients with chronic hepatitis B

BACKGROUND & AIMS

It is unclear whether surrogate end points reported in clinical trials correlate with long-term outcome of patients with chronic hepatitis B.

METHODS

Patients with chronic hepatitis B who participated in any of 4 randomized controlled trials were followed prospectively for liver-related events (hepatocellular carcinoma, ascites, spontaneous bacterial peritonitis, variceal bleeding, liver transplantation, and death). Biochemical (normal ALT levels), virologic (levels of hepatitis B virus DNA below 10,000 copies/mL), and histologic (reduction of necroinflammation grading by 2 points or more with no increase in fibrosis staging) responses were evaluated at the end of each trial.

RESULTS

One hundred ninety-five patients with adequate pretreatment and post-treatment liver biopsies (15 mm long and 6 portal tracts) were followed for 86 months (interquartile range, 77-98). Liver-related events occurred in 12 patients (6%). The risk of liver-related events was lower in patients with biochemical (hazard ratio, 0.21; 95% confidence interval, 0.068-0.68) and histologic (hazard ratio, 0.095; 95% confidence interval, 0.012-0.74) responses. Only 1 patient with a histologic response and 1 patient with an ALT level below Prati's cutoffs (30 IU/L in men and 19 IU/L in women) developed liver-related events. Fifteen of 25 patients (60%) with cirrhosis at baseline had regression of cirrhosis, and none of these patients died or developed liver-related events. In contrast, 3 of these patients still developed liver-related events, despite an initial virologic response, and 2 had virologic breakthrough.

CONCLUSIONS

Biochemical and histologic responses, particularly regression of cirrhosis, in patients with chronic hepatitis B are associated with decreased liver-related complications.