Non-alcoholic fatty liver disease: The diagnosis and management

Non-Alcoholic Fatty Liver Disease and Extra-Hepatic Cancers

Non-alcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease but the second cause of death among NAFLD patients are attributed to malignancies at both gastrointestinal (liver, colon, esophagus, stomach, and pancreas) and extra-intestinal sites (kidney in men, and breast in women). Obesity and related metabolic abnormalities are associated with increased incidence or mortality for a number of cancers. NAFLD has an intertwined relationship with metabolic syndrome and significantly contributes to the risk of hepatocellular carcinoma (HCC), but recent evidence have fuelled concerns that NAFLD may be a new, and added, risk factor for extra-hepatic cancers, particularly in the gastrointestinal tract. In this review we critically appraise key studies on NAFLD-associated extra-hepatic cancers and speculate on how NAFLD may influence carcinogenesis at these sites.

Non-alcoholic fatty liver disease is not associated with a lower health perception

AIM: To examine the association between non-alcoholic fatty liver disease (NAFLD) and general health perception.

METHODS: This cross sectional and prospective follow-up study was performed on a cohort of a sub-sample of the first Israeli national health and nutrition examination survey, with no secondary liver disease or history of alcohol abuse. On the first survey, in 2003-2004, 349 participants were included. In 2009-2010 participants from the baseline survey were invited to participate in a follow-up survey. On both baseline and follow-up surveys the data collected included: self-reported general health perception, physical activity habits, frequency of physician's visits, fatigue impact scale and abdominal ultrasound. Fatty liver was diagnosed by abdominal ultrasonography using standardized criteria and the ratio between the median brightness level of the liver and the right kidney was calculated to determine the Hepato-Renal Index.

RESULTS: Out of 349 eligible participants in the first survey, 213 volunteers participated in the follow-up cohort and were included in the current analysis, NAFLD was diagnosed in 70/213 (32.9%). The prevalence of "very good" self-reported health perception was lower among participants diagnosed with NAFLD compared to those without NAFLD. However, adjustment for BMI attenuated the association (OR = 0.73, 95%CI: 0.36-1.50, P = 0.392). Similar results were observed for the hepato-renal index; it was inversely associated with "very good" health perception but adjustment for BMI attenuated the association. In a full model of multivariate analysis, that included all potential predictors for health perception, NAFLD was not associated with the self-reported general health perception (OR = 0.86, 95%CI: 0.40-1.86, P = 0.704). The odds for "very good" self-reported general health perception (compared to "else") increased among men (OR = 2.42, 95%CI: 1.26-4.66, P = 0.008) and those with higher performance of leisure time physical activity (OR = 1.01, 95%CI: 1.00-1.01, P < 0.001, per every minute/week) and decreased with increasing level of BMI (OR = 0.91, 95%CI: 0.84-0.99, P = 0.028, per every kg/m²) and older age (OR = 0.96, 95%CI: 0.93-0.99, P = 0.033, per one year). Current smoking was not associated with health perception (OR = 1.31, 95%CI: 0.54-3.16, P = 0.552). Newly diagnosed (naive) and previously diagnosed (at the first survey, not naive) NAFLD patients did not differ in their self-health perception. The presence of NAFLD at the first survey as compared to normal liver did not predict health perception deterioration at the 7 years follow-up. In terms of health-services utilization, subjects diagnosed with NAFLD had a similar number of physician’s visits (general physicians and specialty consultants) as in the normal liver group. Parameters in the fatigue impact scale were equivalent between the NAFLD and the normal liver groups.

CONCLUSION: Fatty liver without clinically significant liver disease does not have independent impact on self-health perception.

Hepatitis C virus and neurological damage

Chronic hepatitis C virus (HCV) infection exhibits a wide range of extrahepatic complications, affecting various organs in the human body. Numerous HCV patients suffer neurological manifestations, ranging from cognitive impairment to peripheral neuropathy. Overexpression of the host immune response leads to the production of immune complexes, cryoglobulins, as well as autoantibodies, which is a major pathogenic mechanism responsible for nervous system dysfunction. Alternatively circulating inflammatory cytokines and chemokines and HCV replication in neurons is another factor that severely affects the nervous system. Furthermore, HCV infection causes both sensory and motor peripheral neuropathy in the mixed cryoglobulinemia as well as known as an important risk aspect for stroke. These extrahepatic manifestations are the reason behind underlying hepatic encephalopathy and chronic liver disease. The brain is an apt location for HCV replication, where the HCV virus may directly wield neurotoxicity. Other mechanisms that takes place by chronic HCV infection due the pathogenesis of neuropsychiatric disorders includes derangement of metabolic pathways of infected cells, autoimmune disorders, systemic or cerebral inflammation and alterations in neurotransmitter circuits. HCV and its pathogenic role is suggested by enhancement of psychiatric and neurological symptoms in patients attaining a sustained virologic response followed by treatment with interferon; however, further studies are required to fully assess the impact of HCV infection and its specific antiviral targets associated with neuropsychiatric disorders.

Clinical relevance of dual-energy X-ray absorptiometry (DXA) as a simultaneous evaluation of fatty liver disease and atherosclerosis in patients with type 2 diabetes

Background

Whole body dual-energy X-ray absorptiometry (DXA) can simultaneously measure both regional fat and non-fat mass. Android-to-gynoid (A/G) ratio measured by DXA has been reported to be associated with cardiovascular risks and visceral adiposity; however, little is known regarding its relationship with fatty liver disease and atherosclerosis among patients with diabetes. This study was designed to investigate the association of android and gynoid fat mass measured by DXA with fatty liver disease and atherosclerosis in patients with type 2 diabetes.

Methods

This is a cross-sectional study of 259 patients with type 2 diabetes (mean age 64 ± 13 years; 40.2 % female). Android and gynoid fat mass (kg) were measured by DXA. Skeletal muscle index (SMI) was calculated as appendicular non-fat mass (kg) divided by height (m²). Visceral fat area (VFA, cm²), subcutaneous fat area (SFA, cm²), and liver attenuation index (LAI) were assessed by abdominal computed tomography. Intima media thickness (IMT, mm) in common carotid arteries was determined by carotid ultrasonography.

Results

A/G ratio was significantly correlated with VFA (r = 0.72, p < 0.001), SFA (r = 0.32, p < 0.001) and LAI (r = −0.26, p < 0.001). A/G ratio (standardized β −0.223, p = 0.002) as well as VFA (standardized β −0.226, p = 0.001) were significantly associated with LAI in the univariate model. A/G ratio remained to be significantly associated with LAI (standardized β −0.224, p = 0.005) after adjusting for covariates including body mass index and transaminases. Among patients with low SMI (SMI < 7.0 in male and < 5.4 in female), A/G ratio was significantly associated with carotid IMT in the multivariate model (standardized β 0.408, p = 0.014).

Conclusions

DXA can be used to simultaneously estimate the risks for both fatty liver disease and atherosclerosis in patients with type 2 diabetes.

Subclassification of fatty liver by its pathogenesis: cIEFing is believing

Fatty liver, also termed hepatic steatosis or fatty liver disease, is a condition characterized by excess fat accumulation in the liver. Common causes of fatty liver include obesity, ageing, medications, genetic disorders, viral hepatitis, excess alcohol or toxins. This diversity in pathogenesis is matched by an equally diverse spectrum of consequences, whereby some individuals remain asymptomatic yet others progress through a series of inflammatory, fibrotic and metabolic disorders that can lead to liver failure, cancer or diabetes. Current treatment approaches for fatty liver do not differ by disease aetiology and primarily involve weight loss strategies or management of co-morbidities. In a recent paper published in this journal, Urasaki et al used capillary isoelectric focusing (cIEF) to create profiles of protein post-translational modifications that distinguish four different models of fatty liver in mice. Importantly, this new cIEF approach has the potential to provide rapid individualized diagnosis of fatty liver pathogenesis that may enable more accurate and personalized treatment strategies. Further testing and optimization of cIEF as a diagnostic screening tool in humans is warranted.

Role of Serum Biomarkers in Early Detection of Non-Alcoholic Steatohepatitis and Fibrosis in West Virginian Children

Background

Obesity, an epidemic among West Virginia children, as well as insulin resistance (IR), is well-established contributors to nonalcoholic steatohepatitis (NASH). Progression of NASH can lead to hepatic fibrosis and cirrhosis, making early detection imperative. The standard for diagnosing NASH is histologically via liver biopsy, which is highly invasive and generally contraindicated in children. By studying serum biomarkers associated with NASH, we aim to identify high risk children who can benefit from a less invasive, alternative approach to the early detection of NASH.

Methods

Seventy one children were prospectively recruited and divided into 3 groups: normal weight without IR (control), obese without IR, and obese with IR. Serum samples were drawn for each patient and biomarker levels were assessed via ELISA kits.

Results

Obese without IR and obese with IR patients had significantly elevated levels of lipid metabolism and accumulation markers (FGF-21, NEFA, FATP5, ApoB), oxidative stress markers (dysfunctional HDL, 8-Isoprostane), inflammatory markers(dysfunctional HDL, CK-18) and apoptosis markers (CK-18) compared to control patients (p<0.02). Bilirubin (an antioxidant) was significantly decreased in the obese without IR and obese with IR patients compared to control (p<0.02).

Conclusion

This study showed a correlation between obesity, IR, and biomarkers associated with NASH in pediatrics patients from West Virginia, with obese with IR patients showing the strongest correlation. These findings support the clinical application of these serum biomarkers as a less invasive method for early detection of NASH and hepatic fibrosis.

Interrogating Endogenous Protein Phosphatase Activity with Rationally Designed Chemosensors

We introduce a versatile approach for repurposing protein kinase chemosensors, containing the phosphorylation-sensitive sulfonamido-oxine fluorophore termed Sox, for the specific determination of endogenous protein phosphatase activity from whole cell lysates and tissue homogenates. As a demonstration of this approach, we design and evaluate a direct chemosensor for protein tyrosine phosphatase-1B (PTP1B), an established signaling node in human disease. The optimal sensor design is capable of detecting as little as 6 pM (12 pg) full-length recombinant PTP1B and is remarkably selective for PTP1B among a panel of highly homologous tyrosine phosphatases. Coupling this robust activity probe with the specificity of antibodies allowed for the temporal analysis of endogenous PTP1B activity dynamics in lysates generated from HepG2 cells after stimulation with insulin. Lastly, we leveraged this assay format to profile PTP1B activity perturbations in a rat model of nonalcoholic fatty liver disease (NAFLD), providing direct evidence for elevated PTP1B catalytic activity in this disease state. Given the modular nature of this assay, we anticipate that this approach will have broad utility in monitoring phosphatase activity dynamics in human disease states.

A Novel Wistar Rat Model of Obesity-Related Nonalcoholic Fatty Liver Disease Induced by Sucrose-Rich Diet

The pathogenesis of nonalcoholic fatty liver disease (NAFLD) is not fully understood, and experimental models are an alternative to study this issue. We investigated the effects of a simple carbohydrate-rich diet on the development of obesity-related NAFLD and the impact of physical training on the metabolic abnormalities associated with this disorder. Sixty Wistar rats were randomly separated into experimental and control groups, which were fed with sucrose-enriched (18% simple carbohydrates) and standard diet, respectively. At the end of each experimental period (5, 10, 20, and 30 weeks), 6 animals from each group were sacrificed for blood tests and liver histology and immunohistochemistry. From weeks 25 to 30, 6 animals from each group underwent physical training. The experimental group animals developed obesity and NAFLD, characterized histopathologically by steatosis and hepatocellular ballooning, clinically by increased thoracic circumference and body mass index associated with hyperleptinemia, and metabolically by hyperglycemia, hyperinsulinemia, hypertriglyceridemia, increased levels of very low-density lipoprotein- (VLDL-) cholesterol, depletion of the antioxidants liver enzymes superoxide dismutase and catalase, and increased hepatic levels of malondialdehyde, an oxidative stress marker. Rats that underwent physical training showed increased high-density lipoprotein- (HDL-) cholesterol levels. In conclusion, a sucrose-rich diet induced obesity, insulin resistance, oxidative stress, and NAFLD in rats.

Gastrodin Ameliorates Oxidative Stress and Proinflammatory Response in Nonalcoholic Fatty Liver Disease through the AMPK/Nrf2 Pathway

This study was designed to investigate the antioxidative, antiinflammatory and metabolism-regulating effects of gastrodin (GSTD) in the treatment of nonalcoholic fatty liver disease (NAFLD). Oleic acid (OA) was used to induce steatosis in HL-7702 cells; a high-fat or high-fat and high-cholesterol diet was used to induce NAFLD in mice and rats. Our results showed that GSTD significantly increased hepatic superoxide dismutase (SOD) but decreased reactive oxygen species (ROS)/malondialdehyde (MDA) and reduced the mRNA levels of proinflammatory cytokines both in vitro and in vivo. GSTD promoted the phosphorylation of nuclear factor erythroid-2-related factor-2 (Nrf2) at serine (Ser) 40, stimulated its nuclear translocation and increased hepatic expression of heme oxygenase-1 (HO-1). GSTD activated AMP-activated protein kinase (AMPK), suppressed hepatic steatosis, lowered serum triglyceride (TG)/glucose and decreased body weight gain in animals with NAFLD. The stimulating effects of GSTD on the Nrf2 pathway as well as its antioxidative/antiinflammatory activities were abolished by compound C in OA-treated HL-7702 cells. In summary, our results demonstrate that GSTD activates the AMPK/Nrf2 pathway, ameliorates oxidative stress/proinflammatory response and improves lipid metabolism in NAFLD. Our findings may support the future clinical application of GSTD for the treatment of NAFLD to reduce hepatic steatosis, oxidative stress and proinflammatory response.