Pathologic Impact of Insulin Resistance and Sensitivity on the Severity of Liver Histopathology in Pediatric Non-Alcoholic Steatohepatitis

Reversal of NAFLD After VSG Is Independent of Weight-Loss but RYGB Offers More Efficacy When Maintained on a High-Fat Diet

PURPOSE

Bariatric surgery is emerging as an effective treatment for obesity and the metabolic syndrome. Recently, we demonstrated that Roux-en-Y gastric bypass (RYGB), but not vertical sleeve gastrectomy (VSG), resulted in improvements to white adipose physiology and enhanced brown adipose functioning. Since beneficial alterations to liver health are also expected after bariatric surgery, comparing the post-operative effects of RYGB and VSG on liver physiology is essential to their application in the treatment of non-alcoholic fatty liver disease (NAFLD).

MATERIALS AND METHODS

The effects of RYGB and VSG on liver physiology were compared using diet induced mouse model of obesity. High-fat diet (HFD) was administered for 12 weeks after surgery and alterations to liver physiology were assessed.

RESULTS

Both RYGB and VSG showed decreased liver weight as well as reductions to hepatic cholesterol and triglyceride levels. There were demonstrable improvements to NAFLD activity score (NAS) and fibrosis stage scoring after both surgeries. In RYGB, these beneficial changes to liver function resulted from the downregulation of pro-fibrotic and upregulation anti-fibrotic genes, as well as increased fatty acid oxidation and bile acid flux. For VSG, though similar alterations were observed, they were less potent. However, VSG did significantly downregulate pro-fibrotic genes and showed increased glycogen content paralleled by decreased glycogenolysis which may have contributed to the resolution of NAFLD.

CONCLUSION

RYGB and VSG improve liver physiology and function, but RYGB is more efficacious. Resolutions of NAFLD in RYGB and VSG are achieved through different processes, independent of weight loss.

Prospective assessment of liver stiffness by shear wave elastography in childhood obesity: a pilot study

PURPOSE

The increased incidence of childhood obesity and related non-alcoholic fatty liver disease (NAFLD) has determined the need to identify a non-invasive technique to diagnose and monitor NAFLD. Two-dimensional shear wave elastography (2D-SWE) has emerged as a reliable, non-invasive, tool to evaluate liver tissue elasticity in clinical practice. Aims of this study were to longitudinally evaluate 2D-SWE changes in relation to weight loss, metabolic profile, and body composition modifications and to investigate the correlation between 2D-SWE variation and clinical and biochemical indices of cardio-metabolic risk in obese children.

METHODS

Thirty-three children underwent anthropometric, bioimpedenziometric, fasting biochemical assessments, ultrasound, and SWE evaluations, at baseline (V0) and after a 12-months of follow-up (V12). Diet and physical activity programs have been prescribed to all patients according to European Society of Endocrinology and Pediatric Endocrine Society recommendations. Adherence to the prescribed diet and physical activity program was checked every 3 months during the 12-month of follow-up. Variation of all parameters was evaluated in intragroup and intergroup comparison analysis in children, who had not lost weight (Group A) and those who had lost weight (Group B) at V12. Study population was also analyzed dividing it into two groups with respect to 2D-SWE liver elasticity value ≤10.6 kPa or >10.6 kPa.

RESULTS

A significant reduction of mean 2D-SWE value was demonstrated both in the entire cohort (p = 0.002) and in Group B children (p = 0.004). Intragroup comparison analysis, between V0 and V12, documented a significant decrease of 2D-SWE and BMI SDS and a significant improvement of metabolic profile (decrease of HOMA-IR, HbA1c, oral glucose tolerance test 120-min glucose and insulin, triglycerides, triglycerides/HDL-ratio, transaminases, uric acid, and increase of Matsuda-index and HDL) in children of Group B but not in those of Group A. Intergroup comparison analysis showed significant differences for BMI, BMI SDS, transaminases and several parameters of glucose and lipid metabolism, between Group A and Group B children after 12-months of follow-up. No significant differences were documented with regard to clinical and biochemical variables by dividing the population in accordance with the 2D-SWE cut-off of 10.6 kPa.

CONCLUSIONS

These results suggested a relation between weight loss, metabolic profile improvement and 2D-SWE value reduction. SWE could play a significant role in the non-invasive assessment of NAFLD in children and adolescents with obesity.

Dipeptidyl peptidase-4 inhibitor protects against non-alcoholic steatohepatitis in mice by targeting TRAIL receptor-mediated lipoapoptosis via modulating hepatic dipeptidyl peptidase-4 expression

Dipeptidyl peptidase-4 inhibitors (DPP4i) are antidiabetic medications that prevent cleavage of incretin hormones by dipeptidyl peptidase-4 (DPP4). DPP4 is ubiquitously expressed, and its hepatic DPP4 expression is upregulated under non-alcoholic steatohepatitis (NASH) conditions. We investigated the effect of DPP4i treatment on NASH pathogenesis, as well as its potential underlying molecular mechanisms. Mice were randomly divided into three groups: Group 1, chow-fed mice treated with vehicle for 20 weeks; Group 2, high-fat, high-fructose, and high-cholesterol Amylin liver NASH (AMLN) diet-fed mice treated with vehicle for 20 weeks; Group 3, AMLN diet-fed mice treated with vehicle for the first 10 weeks, followed by the DPP4i teneligliptin (20 mg/kg/day) for additional 10 weeks. DPP4i administration reduced serum liver enzyme and hepatic triglyceride levels and markedly improved hepatic steatosis and fibrosis in the AMLN diet-induced NASH model. In vivo, NASH alleviation significantly correlated with the suppression of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) receptor-mediated apoptosis and downregulated hepatic DPP4 expression. In vitro, DPP4i treatment significantly decreased the markers of TRAIL receptor-mediated lipoapoptosis and suppressed DPP4 expression in palmitate-treated hepatocytes. In conclusion, DPP4i may efficiently attenuate the pathogenesis of AMLN diet-induced NASH in mice by suppressing lipotoxicity-induced apoptosis, possibly by modulating hepatic DPP4 expression.

Gut microbiota modulation as a promising therapy with metformin in rats with non-alcoholic steatohepatitis: Role of LPS/TLR4 and autophagy pathways

Gut microbiota is a crucial factor in pathogenesis of non-alcoholic steatohepatitis (NASH). Therefore, targeting the gut-liver axis might be a novel therapeutic approach to treat NASH. This study aimed to investigate the therapeutic effects of a probiotic (Lactobacillus reuteri) and metronidazole (MTZ) (an antibiotic against Bacteroidetes) either alone or in combination with metformin (MTF) in experimentally-induced NASH. NASH was induced by feeding rats high fat diet (HFD) for 12 weeks. MTF (150 mg/kg/day) or L. reuteri (2x10⁹ colony forming unit/day) were given orally for 8 weeks; meanwhile, MTZ (15 mg/kg/day, p.o.) was administered for 1 week. Treatment with L. reuteri and MTZ in combination with MTF showed additional benefit compared to MTF alone concerning lipid profile, liver function, oxidative stress, inflammatory and autophagic markers. Furthermore, combined regimen succeeded to modulate acetate: propionate: butyrate ratios as well as Firmicutes and Bacteroidetes fecal contents with improvement of insulin resistance (IR). Yet, the administration of MTF alone failed to normalize Bacteriodetes and acetate contents which could be the reason for its moderate effect. In conclusion, gut microbiota modulation may be an attractive therapeutic avenue against NASH. More attention should be paid to deciphering the crosstalk mechanisms linking gut microbiota to non-alcoholic fatty liver disease (NAFLD) to identify new therapeutic targets for this disease.

Non-alcoholic steatohepatitis and progression of carotid atherosclerosis in patients with type 2 diabetes: a Korean cohort study

BACKGROUND

There is increasing concern regarding cardiovascular risk in individuals with non-alcoholic fatty liver disease. This study was conducted to evaluate whether hepatic steatosis with or without fibrosis is associated with the progression of carotid atherosclerosis in patients with type 2 diabetes.

METHODS

From a longitudinal cohort, we enrolled 1120 patients with type 2 diabetes who underwent repeated carotid artery ultrasonography every 1-2 years. Ultrasonographic findings at baseline and after 6-8 years were compared. Presence of hepatic steatosis was mainly assessed by abdominal ultrasonography; patients with hepatic steatosis were further evaluated for hepatic fibrosis according to fibrosis-4 index. We investigated the association between liver status and atherosclerosis progression.

RESULTS

Of 1120 patients, 636 (56.8%) were classified as having hepatic steatosis at baseline. After 6-8 years, 431 (38.5%) showed atherosclerosis progression. Hepatic steatosis was significantly associated with atherosclerosis progression (adjusted odds ratio[AOR]: 1.370, 95% CI 1.025-1.832; p < 0.05). Among patients with hepatic steatosis, only individuals with fibrosis showed significant association with atherosclerosis progression (AOR: 1.615, 95% CI 1.005-2.598; p < 0.05). The association between hepatic fibrosis and atherosclerosis progression was significant in all metabolic subgroups regardless of age, body mass index, presence of metabolic syndrome, or insulin sensitivity (all p < 0.05). Furthermore, subjects with hepatic steatosis & fibrosis and ≥ 4 components of metabolic syndrome criteria showed markedly increased risk of atherosclerosis progression (AOR: 2.430, 95% CI 1.087-5.458; p < 0.05).

CONCLUSIONS

Hepatic steatosis with fibrosis is independently associated with the progression of carotid atherosclerosis in patients with type 2 diabetes.

Insulin resistance associates with hepatic lobular inflammation in subjects with obesity

PURPOSE

Obese subjects with nonalcoholic fatty liver disease (NAFLD) are more prone to develop additional metabolic disturbances such as systemic insulin resistance (IR) and type 2 diabetes. NAFLD is defined by hepatic steatosis, lobular inflammation, ballooning and stage of fibrosis, but it is unclear if and which components could contribute to IR.

OBJECTIVE

To assess which histological components of NAFLD associate with IR in subjects with obesity, and if so, to what extent.

METHODS

This cross-sectional study included 78 obese subjects (mean age 46 ± 11 years; BMI 42.2 ± 4.7 kg/m2). Glucose levels were analysed by hexokinase method and insulin levels with electrochemiluminescence. Homeostasis model assessment-estimated insulin resistance (HOMA-IR) was calculated. Liver biopsies were evaluated for histological components of NAFLD.

RESULTS

A positive association between overall NAFLD Activity Score and HOMA-IR was found (r s = 0.259, P = 0.022). As per individual components, lobular inflammation and fibrosis stage were positively associated with HOMA-IR, glucose and insulin levels (P < 0.05), and HOMA-IR was higher in patients with more inflammatory foci or higher stage of fibrosis. These findings were independent of age, BMI, triglyceride levels, diabetes status and sex (all P < 0.043). In a combined model, lobular inflammation, but not fibrosis, remained associated with HOMA-IR.

CONCLUSION

In this group of obese subjects, a major contributing histological component of NAFLD to the relation between NAFLD severity and IR seems to be the grade of hepatic lobular inflammation. Although no causal relationship was assessed, preventing or mitigating this inflammatory response in obesity might be of importance in controlling obesity-related metabolic disturbances.

The clinical significance of insulin resistance in non-diabetic patients with early forms of non-alcoholic fatty liver disease

AIM

To assess the presence of insulin resistance (IR) in non-diabetic patients with early forms of non-alcoholic fatty liver disease (NAFLD) - liver steatosis (LS) and steatohepatitis (SH) of mild activity and the influence of IR on the clinical course of these diseases.

MATERIALS AND METHODS

134 patients with NAFLD were examined: 54 with LS and 80 with SH. The control group consisted of 37 healthy donors. Anthropometric parameters (body mass index (BMI), waist circumference (WC)), clinical and biochemical blood indices, including the blood level of cytokeratin-18 fragments (CK-18), TNF-α and IL-6 cytokines, insulin were evaluated. The HOMA index and the fibrosis index (NAFLD FS) were calculated. Patients were divided into groups: I - with the absence of IR (HOMA-index &lt;2.7), II - with the presence of IR (HOMA-index&gt; 2.7).

RESULTS

Indicators of hepatic injury, inflammation, cholestasis, fibrosis and atherogenic dyslipidemia are higher in patients with LS of group II (with IR) than in group I patients (without IR). BMI, WC, γ-glutamil transpeptidase, CK-18 and fibrosis index are significantly higher in group II patients with SH compared with group I, there is no significant difference in the level of cytolysis, inflammation and dyslipidemia indices. A high incidence of IR in non-diabetic patients with LS (37.0%) and SH (55.0%) was found and the effect of IR on the clinical course of these diseases was revealed.

CONCLUSION

Insulin resistance in non-diabetic patients with NAFLD was detected in SH (55.0%) with higher frequency than in LS (37.0%). In LS, IR is associated with impaired hepatic cell damage, intrahepatic cholestasis, atherogenic dyslipidemia and fibrosis. In SH, IR is combined with reliable growth in indicators of hepatocyte apoptosis, cytokine proinflammatory status and fibrosis. IR determines the progressing course of NAFLD, promoting the transformation of steatosis into steatohepatitis and steatohepatitis into fibrosis and liver cirrhosis.

Normal serum alanine aminotransferase and non-alcoholic fatty liver disease among Korean adolescents: a cross-sectional study using data from KNHANES 2010-2015

Background

Non-alcoholic fatty liver disease (NAFLD) is complicated disease and increasing worldwide. Previously, many studies of NALFD prevalences have used alanine aminotransferase (ALT) of > 40 U/L to define NAFLD, although that is too high to be reliable among adolescents. This study aimed to define the upper normal limit of ALT among Korean adolescents, and use it to estimate the prevalence of NAFLD, based on data from the Korea National Health and Nutrition Examination Survey (KNHANES).

Methods

Data were obtained from 1785 healthy adolescents (916 boys and 869 girls, 10–18 years old) who participated in the KNHANES during 2010–2015. The International Diabetes Federation metabolic syndrome criteria for adolescents were used to exclude participants with metabolic syndrome components. Furthermore, participants who previously had diseases related to low HDL levels, high TG levels, diabetes, or very low/high body mass index and hepatitis B were excluded. The 95th percentiles level of ALT from healthy participants were evaluated. The definition of NAFLD was overweight status (≥85th percentile of body mass index) plus elevated ALT levels (95th percentile).

Results

The upper normal ALT were 24.1 U/L for boys and 17.7 U/L for girls. Based on these values, the estimated prevalences of NAFLD in 2015 were 8.9% among adolescents.

Conclusion

Defining the upper normal limit of ALT can be adjusted for each sex and ethnics in the general population. ALT laboratory thresholds used for children should be re-examined. The physicians should be aware not to underdiagnose NAFLD patient even ALT level is < 40 U/L.

Estimated Prevalence of Adolescents with Nonalcoholic Fatty Liver Disease in Korea

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) has become prevalent worldwide in the last decade. However, the recent prevalence of NAFLD in adolescents has not yet been investigated in Korea.

METHODS

Data were obtained from 1,416 participants aged 10-18 years from the Korea National Health and Nutrition Examination Survey conducted in 2010 and 2015. Systolic blood pressure (SBP), diastolic blood pressure (DBP), height, weight, waist circumference (WC), body mass index (BMI), fasting glucose, total cholesterol, high-density lipoprotein (HDL), aspartate aminotransferase (AST), alanine aminotransferase (ALT) level, waist-to-height ratio (WHtR), and pediatric NAFLD fibrosis index (PNFI) were analyzed.

RESULTS

SBP, weight, WC, BMI, WHtR, and total cholesterol level were significantly higher in 2015 than in 2010. Prevalence of NAFLD (BMI ≥ 85th percentile plus ALT > 30 U/L for boys and ALT > 19 U/L for girls) were 4.7% in 2010 and 5.9% in 2015 (P = 0.360). Using various cutoffs for the ALT level (> 40, > 30, > 25.8 U/L for boys and >22.1 U/L for girls) NAFLD prevalence rates were 3.0%, 4.1%, and 5.5% in 2010; 2.9%, 5.0%, and 7.1% in 2015, respectively (P = 0.899, 0.469, and 0.289). Boys had a higher SBP, DBP, height, weight, WC, BMI, WHtR, fasting glucose, total cholesterol, ALT, and lower HDL level than girls. The probability of liver fibrosis using the PNFI varies between 21.3% and 24.5% among NAFLD participants (P < 0.001).

CONCLUSION

The Korean society needs to quickly control the increasing prevalence of NAFLD in adolescents and reduce its complications.