Intestinal Microbiota and NAFLD Pre and Post Bariatric Surgery

November 1, 2022 updated by: Johane Allard

Role of Intestinal Microbiota in Non-alcoholic Fatty Liver Disease Pre and Post bAriatric Surgery

Non-alcoholic fatty liver disease (NAFLD) includes benign hepatic simple steatosis (SS) and steatohepatitis (NASH), which is characterised by inflammation leading to fibrosis and cirrhosis. NAFLD is the hepatic manifestation of the metabolic syndrome, and the prevalence is 74-98% in morbidly obese individuals undergoing bariatric surgery. Although steatosis improves post bariatric surgery, hepatic inflammation and fibrosis do not consistently improve. Alterations of the human gut flora (intestinal microbiota; IM) may play a role. One mechanism linking IM to obesity, insulin resistance (IR), and NAFLD is through translocation of bacterial lipopolisaccharide (LPS=endotoxin) into the blood stream (=endotoxemia), causing chronic inflammation. Morbidly obese subjects have different IM compared to lean controls, and the IM structure is significantly altered after bariatric surgery, probably due to a combination of anatomic changes, diet, and weight loss. For example, the ratio of Firmicutes/Bacteroidetes may be lower in obese subjects compared to lean controls and lower numbers of Faecalibacterium prausnitzii were reported in some obese subjects before bariatric surgery, which increased 3 months post-surgery. This is of interest since, in animal studies, low abundance of F. prausnitzii, a butyrate producing bacterium, is associated with increased intestinal permeability, endotoxemia, and inflammation. To our knowledge, only two studies are available describing IM in patients pre and post bariatric surgery, and no data have been published on the relationship between IM and NAFLD in these patients.

Study Overview

Status

Active, not recruiting

Conditions

Detailed Description

Study Design: A. Cross-sectional study: Sixty patients with morbid obesity undergoing bariatric surgery diagnosed with NAFLD on liver biopsy (30 SS, 30 NASH). Main hypothesis: The ratio of Firmicutes/Bacteroidetes is higher in stool samples from morbidly obese subjects with NASH compared to SS. Other differences in IM composition exist. Objective: to compare bacterial dynamics using Illumina technology to assess the IM. The relative abundance of the dominant fecal microorganisms (including Firmicutes, Archaea, Bacteroides, Bifidobacteria, Mollicutes, Enterobacteriaceae, Clostridia clusters, F. prausnitzii, Roseburia, and Lactobacilli) will also be assessed by real-time PCR. Sub-hypotheses: In NASH compared to SS, there will be: a) lower fecal butyrate concentration; b) higher endotoxin and other inflammatory markers (TNF-α, IL-6) in plasma. Potential covariates assessed: small intestinal bacterial overgrowth (SIBO), measured by glucose hydrogen breath test (GHBT), which can contribute to endotoxemia and inflammation; IR, diabetes status, lipid profile, plasma vitamin E, liver enzymes, anthropometry, food intake, physical activity and environmental factors.

B. Prospective cohort study: Patients undergoing bariatric surgery with either SS or NASH (up to 60 of them recruited from Part A) will be followed prospectively over 12 months to assess changes in the IM and liver histology. Goal is to have 60 subjects who complete the study with a 2nd liver biopsy. Main Hypothesis: In morbidly obese patients with NAFLD (SS or NASH), changes in IM post bariatric surgery will be associated with changes in liver histology. Specifically, an increased number of F. prausnitzii in feces with be associated with improvement in liver histology while a reduction will be associated with deterioration of liver histology. Objective: To correlate changes in liver histology (NAFLD activity score [NAS], inflammation, fibrosis, steatosis) between 0 and 12 months with changes in F. prausnitzii. Other changes of the fecal IM community structure, fecal short chain fatty acids (including butyrate), plasma endotoxin, inflammatory markers (TNF-α, IL-6) and SIBO will also be assessed, in addition to diet, activity, weight change, improvement of diabetes and plasma vitamin E. Secondary hypotheses: Increased number of F. prausnitzii in feces will be associated with increased fecal butyrate, lower serum endotoxin and lower inflammatory markers (TNF-α, IL-6) in plasma.

Significance: In humans with morbid obesity and NAFLD undergoing bariatric surgery, very little data are available on IM and its metabolic effect and contribution to NAFLD. These studies will add more information regarding the role of IM and its effect on potential mechanisms contributing to NAFLD. It will also provide us with pilot data for future intervention studies assessing the potential use of pre- or probiotics for NAFLD in morbidly obese subjects in the setting of bariatric surgery.

Study Type

Observational

Enrollment (Anticipated)

120

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • Canada
    • Ontario
      • Toronto, Ontario, Canada, M5G 2C4
        • University Health Network

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

14 years and older (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

All

Sampling Method

Probability Sample

Study Population

NAFLD is the hepatic manifestation of the metabolic syndrome, and the prevalence is 74-98% in morbidly obese individuals. The aim of this study is to examine the role of intestinal microbiota (IM) in non-alcoholic fatty liver disease (NAFLD) in morbidly obese patients undergoing Roux-en-Y gastric bypass surgery. Alterations of the human gut flora (intestinal microbiota) will be determined before and after surgery in realtion with the change of liver histology.

Description

Inclusion Criteria:

  • BMI>40 kg/m2 or BMI>35-40 kg/m2 with severe weight loss comorbidities
  • Male or female, equal or over 18 years of age
  • Alcohol consumption is leass than 20 g/d

Exclusion Criteria:

  • No diagnosis of NAFLD
  • Having liver disease of other etiology
  • Having advance liver disease
  • Having abnormal coagulation or other reason contraindicating a Liver Biopsy
  • On medication known to precipitate steatohepatitis 6 months prior to entry
  • On regular intake of non-steroidal anti-inflammatory drugs, prebiotics, probiotics and antibiotics, ursodeoxycholic or any experimental drug in the 3 months prior to study entry
  • Having type-1 diabetes, chronic gastrointestinal diseases, previous gastrointestinal surgery modifying the anatomy (prior to bariatric surgery)
  • Smoking
  • Pregnancy or Breastfeeding

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Observational Models: Cohort
  • Time Perspectives: Prospective

Cohorts and Interventions

Group / Cohort
Bariatric surgery of morbid obese
Morbid obese patient who undergo Bariatric surgery with NAFLD (NASH or SS) status

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Firmicutes/Bacteroides ratio in feces
Time Frame: Baseline, 6, 12 months
16S rRNA sequencing will be performed on the Ion Torrent platform
Baseline, 6, 12 months

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall microbiota composition, amount of selected groups of microorganisms and concentration of Short Chain Fatty Acid (SCFA) in stool sample
Time Frame: 8 months
Lower fecal butyrate concentration in NASH vs SS
8 months
The amount of endotoxin, TNF-alfa and IL-6 in plasma/serum
Time Frame: 8 months
Higher plasma endotoxin and pro-inflammatory markers (TNF-alfa and IL-6) in NASH vs SS.
8 months
The change in inflammation, fibrosis, steatosis in liver histology
Time Frame: 12 months
Change in the number of F. prausnitzii in stool between baseline and 12 months related with the change in liver histology
12 months
NAFLD activity score
Time Frame: baseline, 12 months
NAFLD Activity score (Kleiner) on liver histology
baseline, 12 months

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Johane Allard

Collaborators

Canadian Institutes of Health Research (CIHR)

Investigators

  • Principal Investigator: Johane Allard, MD. FRCPC, University Health Network, Toronto

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

June 1, 2013

Primary Completion (Actual)

June 30, 2022

Study Completion (Anticipated)

August 30, 2023

Study Registration Dates

First Submitted

May 14, 2013

First Submitted That Met QC Criteria

May 14, 2013

First Posted (Estimate)

May 17, 2013

Study Record Updates

Last Update Posted (Actual)

November 2, 2022

Last Update Submitted That Met QC Criteria

November 1, 2022

Last Verified

November 1, 2022

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 13-6115-A

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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