Accuracy of FibroScan Controlled Attenuation Parameter and Liver Stiffness Measurement in Assessing Steatosis and Fibrosis in Patients With Nonalcoholic Fatty Liver Disease

1. Download high-res image (357KB)
2. Download full-size image

     

Symptoms of Obstructive Sleep Apnea in Patients with Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is a term often used to describe two related conditions: a relatively benign, nonalcoholic fatty liver (NAFL) and potentially aggressive, nonalcoholic steatohepatitis (NASH). Both conditions (NAFL and NASH) occur in the setting of peripheral insulin resistance. Recently, obstructive sleep apnea (OSA) has been proposed as an independent risk factor for insulin resistance. To date, few studies have documented the prevalence of OSA or symptoms of OSA (SOSA) in NAFLD patients. The objectives of this study were (1) to document the prevalence of SOSA in patients with NAFLD and (2) to determine whether prevalence rates for SOSA differ in NAFL versus NASH patients. One hundred ninety biochemically defined NAFLD patients (116 NAFL and 74 NASH), of whom 50 (18 NAFL and 32 NASH) had undergone liver biopsy, completed a Modified Berlin Sleep Apnea Questionnaire for SOSA. Risk factors for NAFLD were also documented in NAFL and NASH patients. Eighty-seven of the 190 (46%) NAFLD patients met questionnaire criteria for SOSA. The prevalence of SOSA was similar in both biochemically (45% versus 49%, respectively; P= 0.66) and histologically (39% versus 63%, respectively; P= 0.11) defined NAFL and NASH patients. Other risk factors for NAFLD such as body mass index, plasma cholesterol and triglyceride levels, and prevalence of diabetes were also similar in the two groups. Approximately one-half of NAFLD patients, whether NAFL or NASH, have SOSA. Further studies are required to determine whether a causal link exists between NAFLD and OSA.     

Nonalcoholic Fatty Liver Disease: Noninvasive Methods of Diagnosing Hepatic Steatosis

Hepatic steatosis is the buildup of lipids within hepatocytes. It is the simplest stage in nonalcoholic fatty liver disease (NAFLD). It occurs in approximately 30% of the general population and as much as 90% of the obese population in the United States. It may progress to nonalcoholic steatohepatitis, which is a state of hepatocellular inflammation and damage in response to the accumulated fat. Liver biopsy remains the gold standard tool to diagnose and stage NAFLD. However, it comes with the risk of complications ranging from simple pain to life-threatening bleeding. It is also associated with sampling error. For these reasons, a variety of noninvasive radiological markers, including ultrasound, computed tomography, magnetic resonance spectroscopy, and the controlled attenuation parameter using transient elastography and Xenon-133 scan have been proposed to increase our ability to diagnose NAFLD, hence avoiding liver biopsy. The aim of this review is to discuss the utility and accuracy of using available noninvasive diagnostic modalities for fatty liver in NAFLD.     

Increased Orocecal Transit Time in Patients with Nonalcoholic Fatty Liver Disease

Intestinal bacterial overgrowth (IBO) has been suggested to play a pathogenic role in patients with nonalcoholic fatty liver disease (NAFLD). Delayed intestinal transit may contribute to IBO development. Ten nondiabetic patients with NAFLD and abnormal liver enzymes were recruited. Ten healthy individuals, matched by sex, age, and body mass index, were used as controls. Orocecal transit time (OCTT) was measured by the lactulose breath test. Anti-endotoxin core antibodies (EndoCAb) were determined. The effect of oral norfloxacin (400 mg BID during 2 weeks) on liver enzymes, lactulose breath test, and EndoCAb was also studied. NAFLD patients had higher basal breathed H₂ and prolonged OCTT compared to controls (127 ± 61 vs. 57 ± 23 min, respectively; P = 0.0037). EndoCAb titers were similar in NAFLD patients and controls. Norfloxacin administration had no effect on ALT levels, lactulose breath test, or EndoCAb titers in patients with NAFLD. The present data show evidence of deranged intestinal motility in nondiabetic patients with NAFLD and support the hypothesis that NAFLD could be linked to endotoxin-induced liver damage of intestinal origin.This work was supported in part by a grant from the Centro de Investigaciones Médicas Pontificia Universidad Católica to A.S. and Fondo Nacional de Ciencia y Tecnología (FONDECYT No. 1020641) to M.A.