Tag Archives: nonalcoholic steatohepatitis

Breakthrough for Fatty Liver Disease?

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Could bile acids play a role in reducing metabolic syndrome and in particular fatty liver disease?  This question is now being studied (Gastroenterology 2013; 145: 574-82).

This recent study examined whether obeticholic acid (OCA) which is a semisynthetic derivative of the human bile acid chenodeoxycholic acid could aid with insulin resistance and ultimately nonalcoholic fatty liver disease (NAFLD).  OCA is an agonist of the farnesoid X receptor which is a nuclear hormone receptor that regulates glucose and lipid metabolism.

The authors performed a phase 2, double-blind, placebo-controlled study to assess the effects of OCA on insulin sensitivity in patients with NAFLD and type 2 diabetes mellitus.  Patients received either placebo (n=23), 25 mg OCA (n=20), or 50 mg OCA (n=21) once daily for 6 weeks.  Using an insulin clamp, insulin sensitivity was measured before and after the study period.  Numerous blood tests were obtained as well.

Results:

  • Insulin sensitivity improved 28% in the 25mg OCA group and 20.1% in the 50 mg OCA group whereas it decreased 5.5% in the placebo group.
  • The OCA groups also had significant reductions in gamma-glutamyltransferase, alanine aminotransferase, and dose-related weight loss.
  • Markers of liver fibrosis decreased in the 25 mg OCA group.
  • Side effects of OCA were minimal.  Constipation was reported in the 50 mg OCA group.

Take-home message: OCA may help patients with NAFLD and a bigger, longer study is in the works (FLINT study: 25 mg OCA for 72 weeks compared with placebo, http://www.clinicaltrials.gov; NCT01265498)

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Pediatric Fatty Liver Disease -in the news

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An excerpt from The Wall Street Journal, Fatty Liver Disease: More Prevalent in Children (also covered by this blog previously: Increasing prevalence of pediatric NAFLD | gutsandgrowth):

A type of liver disease once thought to afflict primarily adult alcoholics appears to be rampant in children.

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Some 1 in 10 children in the U.S., or more than 7 million, are thought to have the disease, according to recent studies.

The condition, in which the normally rust-colored organ becomes bloated and discolored by yellowish fat cells, has become so common in non-drinkers that it has been dubbed nonalcoholic fatty liver disease.

The disease’s prevalence is alarming doctors who worry about its progression to nonalcoholic steatohepatitis, or NASH, when the fatty liver becomes inflamed and cells are damaged. That leads to the end stage of cirrhosis, when the liver forms scar tissue and ultimately stops working.

Organ Damage

Some facts about nonalcoholic fatty liver disease:

  • About 10% of children in the U.S. are thought to have the condition.
  • Several factors likely contribute, including genetics, obesity, diet and insulin resistance.
  • It has no detectable symptoms.
  • Weight loss is the standard treatment for earlier stages of liver disease.

The condition’s rise is tied to the obesity epidemic—about 40% of obese children have it—but isn’t caused solely by being overweight. The disease appears to be growing among normal-weight children too, experts say.

And even though obesity rates are starting to level off, the prevalence of fatty liver disease continues to rise, they say.

It also has no symptoms, which means a person could have it for decades without knowing. 

Full link:

Fatty Liver Disease: More Prevalent in Children

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Ultrasound Unreliable to Exclude Fatty Liver

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More information on the sensitivity of ultrasonography for detecting fatty liver is available in the setting of living-related liver transplantation (Transplantation 2013; 95: DOI: 10.1097/TP.0b013e31828d1588).

In this study the authors retrospectively examined the degree of steatosis from 492 living liver donors who had normal ultrasounds and normal aminotransferase levels. The median age of the donors was 30.1 year and the median BMI was 22.4 kg/meter-squared.

Background: According to the authors, if liver histology shows severe macrosteatosis (>60%), transplantation is canceled.  Furthermore, in cases of moderate macrosteatosis (30-59%), the risks/benefits need to be considered on an individual basis due to increased risk of mortality; Spitzer et al (reference below) demonstrated that macrovesicular steatosis >30% was an independent predictor of reduced 1-year graft survival.  In addition, a previous report has indicated that both macrosteatosis and microsteatosis had similar impacts on postoperative  liver function.

Results:

  • 3 (0.6%) had severe total steatosis, moderate or greater steatosis was diagnosed in 4 (0.8%) for macrosteatosis, in 26 (5.3%) for microsteatosis, and 56 (11.4%) for total steatosis.
  • There were two identified risk factors BMI >23 kg/meter-squared and triglycerides >88 mg/dL.  Individuals with both risk factors had a 28.6% prevalence of moderate or greater degree of total steatosis compared with 6.6% with no risk factors.  In these individuals, a liver biopsy may be worthwhile.

Why this study matters for the non-transplant physician:  This study provides additional data that ultrasonography is not adequate to exclude significant degrees of fatty liver.

Study limitations included the retrospective analysis which relied on medical record accuracy, degree of steatosis was not based on a single pathologist, ultrasonography was not based on not based on a single radiologist, both BMI and triglycerides may vary based on age, gender, ethnicity and other factors.

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Related references:

  • -Spitzer AL et al. Liver Transpl 2010; 16: 874-84.
  • -Liver Transpl 2013; 19: 437-49. Difficulty with precisely determining steatosis
  • -Hepatology 2011; 54: 1082.  U/S w ~85% sensitivity in detecting fatty liver.
  • -Gastroenterol 2008; 135: 1961.  Liver biopsy (in pediatrics) still needed as surrogates not accurate for correlating degree of fibrosis/injury.
  • -J Pediatr 2009; 155: 469.  Review.  No evidence-based guidelines for treating in pediatrics –main Rx wt loss/exercise.  Consider obtaining ultrasound.

Increasing prevalence of pediatric NAFLD

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A recent study shows that the prevalence of nonalcoholic fatty liver disease (NAFLD) in adolescents has increased over a 20 year period in the U.S. (J Pediatr 2013; 162: 496-500).

Using a cross-sectional data from 12,714 adolescents, aged 12-19, from the National Health and Examination survey, the prevalence of suspected NAFLD has more than doubled over the past 20 years and currently affects nearly 11% of adolescents.  Approximately one-half (48%) of obese males have NAFLD.

Suspected NAFLD was defined as elevated ALT in an overweight or obese child.  Specific ALT values were chosen using sex-specific cut points (>25.8 U/L for boys and >22.1 for girls).

  • Besides increased NAFLD, the prevalence of obese BMI (≥95%) and severe obesity (BMI ≥99%) also increased steadily.  Between 1988-1994, obese BMI accounted for 11.2% and severe obese BMI 1.5%.  By 2007-2010, these increased to 20.% and 5.5% respectively.
  • For suspected NAFLD, in 1988-94 compared to 2007-2010, the prevalence went from 3.9% to 10.7%.

Probably the biggest limitation of this study was considering “suspected NAFLD” only in overweight or obese children.  The authors chose to do this to increase the specificity of their diagnosis and avoid overestimating the prevalence of NAFLD.

Related blog posts:

NAFLD Guidelines 2012 | gutsandgrowth

Pediatric NAFLD histology score | gutsandgrowth

Gut microbiome and endogenous alcohol

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At first glance, it sounds like an ambitious project -develop a gut microbiome that produces alcohol.  It could obviate the need for “Duff” beer (Duff Beer – Wikipedia, the free encyclopedia).  Yet, a recent article has found that an altered microbiome with increased endogenous alcohol already exists and it is associated with nonalcoholic steatohepatitis (NASH) (Hepatology 2013; 57: 601-609).

In this study, the authors examined three pediatric populations: a healthy control group (n=16), obese group (n=25), and NASH group (n=22).  All NASH patients had undergone liver biopsy and met Kleiner’s criteria; in contrast, the obese group had normal LFTs.

Key study findings:

1. The microbiome from the obese and NASH patients were similar but had some striking differences compared with the control group patients (pie chart –Figure 2):

  • Bacteroidetes (including Bacteroides): 28.65% in healthy controls, 50.28% in obese, and 49.11% in NASH
  • Firmicutes (including Blautia and Faecalibacterium): 66.78% in healthy controls, 42.62% in obese, and 42.39% in NASH
  • Proteobacteria (including Escherichia): 0.87% in healthy controls, 3.13% in obese, and 6.03% in NASH

2. Elevated serum ethanol concentrations only in NASH population: ~26 μM in both control and obese groups compared with ~35 μM in NASH patients.

Under normal conditions, endogenous alcohol is produced in the human body and the intestinal microflora are the major source.  This gut-produced alcohol is quickly metabolized by the liver.  Due to similar histology between NASH patients and patients with alcoholic liver disease, it has been hypothesized that NASH patients may have elevated blood alcohol.  This study adds further evidence to this hypothesis and provides a potential mechanism; namely, increased bacteria like Escherichia and Bacteroides can increase endogenously-produced alcohol.

Will efforts to revert the microbiome to normal have therapeutic effects on NASH?  This important question will need to be addressed given the growing problem of fatty liver disease.

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