Nonalcoholic Fatty Liver Disease, Nonalcoholic Steatohepatitis, Steatosis
Conditions
Keywords
Nonalcoholic fatty liver disease, Steatosis, Nonalcoholic steatohepatitis
Brief summary
The first aim of this study is to assess oxidative stress and nutritional status in patients with elevated liver enzymes who were found to have either simple steatosis (SS) or nonalcoholic steatohepatitis (NASH) or normal histological findings on liver biopsy by measuring liver lipid peroxides and tumor necrosis factor (TNF)-α, liver pathology and immunohistochemistry, liver function tests, liver and red blood cell membrane fatty composition, insulin resistance (IR) parameters, plasma lipid peroxides, plasma antioxidant vitamins and antioxidant power, lipid profile, subject demographics, medical history and medication use. The second aim is to detect differences in hepatic gene expression (messenger RNA, mRNA) and epigenetic regulation (micro RNA, miRNA) between patients with SS or NASH and healthy controls, in addition to determine in patients with non-alcoholic fatty liver disease (NAFLD = SS+NASH combined) whether there is an association between hepatic n-3 PUFA content and gene expression. The third aim is to determine the intestinal microbiome (microbial composition and metagenome) in patients with SS or NASH and healthy controls.
Detailed description
NASH is associated with obesity, diabetes and hyperlipidemia. Fat accumulation in the liver is likely due to variable degrees of disordered fatty-acid metabolism and insulin resistance (IR). Liver steatosis, especially polyunsaturated fatty acids (PUFA) in the liver, increases lipid peroxidation and is associated with a reduction in the antioxidant defense system. This oxidative stress can lead to increased production of pro-inflammatory cytokines (TNF-α, transforming growth factor-beta) contributing to the development of steatohepatitis and fibrosis.TNF-α - may further contribute to IR. In addition, changes in fatty acid composition within the liver may influence lipid metabolism and inflammation. In particular, n-3 PUFA have an effect on the insulin sensitivity, transcription of antioxidant genes, inflammatory response and production of reactive oxygen species. Differences might be seen on the gene expression level (mRNA) and also in epigenetic regulation (miRNA). Microbiota composition might influence energy metabolism, and inflammatory tone and IR through increased endotoxemia and therefore could also play a role in the development of NAFLD.
Interventions
None listed
Sponsors
Canadian Liver Foundation
Canadian Institutes of Health Research (CIHR)
American College of Gastroenterology
Johane Allard
Study design
Observational model
COHORT
Time perspective
CROSS_SECTIONAL
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* Male and female patients, age \>18 y * A liver biopsy with a diagnosis of SS or NASH OR No signs of steatosis, fibrosis or any other kind of liver disease on histology (minimal findings) OR For healthy control subjects, those with normal liver enzymes and normal liver imaging on ultrasound * alcohol consumption (\<20g of ethanol per day); * absence of any other possible cause for liver dysfunction.
Exclusion criteria
* any other liver disease apart from NAFLD * anticipated need for liver transplantation in one year or complications of liver disease; * any reasons contraindicating a liver biopsy (patients) or liver donation (healthy donors) * chronic gastrointestinal diseases, previous gastrointestinal surgery modifying the anatomy, patients with diabetes requiring insulin. * medications known to precipitate steatohepatitis (corticosteroids, high dose estrogens, methotrexate, amiodarone, spironolactone, sulfasalazine, perhexiline maleate, diethylamino- ethoxyhexestrol (DH), tamoxifen, diethylstilbestrol, naproxen or oxacillin) or regular intake of non-steroidal anti-inflammatory drugs (except for low dose aspirin), use of ursodeoxycholic acid or any experimental drug in the 6 months prior to entry. * regular intake of prebiotics, probiotics, antibiotics, or laxatives; in the 3 months prior to study entry * Pregnant or lactating
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Hepatic fatty acid composition in total lipids in liver biopsy | Baseline | Gas chromatography |
| Hepatic gene expression | Baseline | mRNA by microarray |
| Intestinal microbiota composition | Baseline | Illumina 16S technology |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Intestinal microbiota - specific organisms and groups | Baseline | Quantitative real-time polymerase chain reaction |
| Intestinal microbiome on a genetic level | Baseline | Illumina sequencing technology |
| Lipid peroxides in the liver | Baseline | Test kit |
| Plasma endotoxin | Baseline | Limulus assay |
| Short-chain fatty acids in stool | Baseline | Gas chromatography |
| Hepatic liver antioxidant power | Baseline | Test kit |
| Hepatic microRNA expression in the liver | Baseline | NanoString |
Other
| Measure | Time frame | Description |
|---|---|---|
| Insulin resistance | Baseline | Fasting glucose and insulin to calculate insulin resistance (HOMA-IR), C-peptide, hemoglobin A1c, all by standard laboratory methods |
| Plasma ethanol | Baseline | standard laboratory measurement |
| Anthropometry | Baseline | Weight, height, skinfolds, bioelectrical impedance analysis |
| Immunohistochemistry | Baseline | Staining for malondialdehyde, alpha-smooth muscle actin, transforming growth factor beta |
| Physical activity | Baseline | 7 day activity logs |
| Factors influencing intestinal microbiota | Baseline | Environmental questionnaire |
| Liver function tests | Baseline | Alanine transaminase, aspartate transaminase, alkaline phosphatase, standard laboratory tests |
| Food intake | Baseline | 7-day food records |
| TNF-alpha in the liver | Baseline | Enzyme linked immunosorbent assay |
| Hepatic phospholipid composition | Baseline | Gas chromatography |
| Red blood cell fatty acid and phospholipid composition | Baseline | Gas chromatography |
| Plasma fatty acid composition | Baseline | Gas chromatography |
| Plasma lipid peroxides | Baseline | Test kit |
| Plasma antioxidant vitamins | Baseline | Vitamin C colorimetric, alpha- and gamma-tocopherol and beta-carotene by high-performance liquid chromatography |
| Serum antioxidant power | Baseline | Test kit |
| Free choline in serum | Baseline | liquid chromatography/electrospray ionization-isotope dilution mass spectrometry (LC/ESI-IDMS) |
| Bacterial DNA in plasma | Baseline | Quantitative polymerase chain reaction for bacterial 16S rDNA |
Countries
Canada
Outcome results
None listed