A non-invasive comparison between NASH and Crohn's disease

Hepatic steatosis and non-alcoholic steatohepatitis (NASH) show an increasing prevalence in multiple alimentary tract diseases, including inflammatory bowel diseases (IBD) as indicated in recent studies while we and others have shown that NASH in IBD patients is associated with an increased susceptibility for acute-on-chronic liver failure. So far, little is known about the underlying mechanisms inducing hepatic steatosis in IBD. We aimed to analyze and compare non-invasive markers of liver injury in patients with NASH and individuals with Crohn's disease (CD). Here, we included patients with established NASH and those with established CD without a history of liver disease and analyzed serum parameters of liver injury and hepatocellular apoptosis (M30), a breath test for small intestinal bacterial overgrowth (SIBO) and transient elastography as well as controlled attenuation parameter (CAP) to characterize hepatic steatosis. Patients with NASH had a significantly higher BMI compared to CD, expectedly. Hence, ALT and AST levels as well as M30 were significantly higher in NASH vs. CD. SIBO occurred in only few individuals and did not affect steatosis. Interestingly, while transient elastography revealed increased liver stiffness in NASH vs. CD, there was no significant difference in CAP as an assessment for hepatic steatosis comparing the groups. Actually, 43.8% of CD patients had a CAP > 283dB/m, defined as a previously established cutoff value for significant hepatic steatosis with a maximum CAP of 400dB/m in one patient. In general, transaminases were within normal limits in most patients but in CD patients with CAP > 283dB/m AST and ALT levels were significantly higher compared to CD patients with lower CAP results. Thereupon we reviewed the patients' drug regimens in order to determine potential influences resulting in higher CAP values. Much to our surprise we found steroid therapy was not associated with CAP in this cohort. However, individuals with CAP below 283dB/m were more likely to be treated with biologicals. Here we revealed that CAP was significantly lower in patients treated with biologicals as compared to other treatment plans (237.3 ± 11.7 vs. 306.2 ± 20.6 dB/m; p < 0.05). Thus, in this cohort, NASH was associated with higher BMI, transaminase as well as M30 levels and liver stiffness, while hepatic steatosis as assessed by CAP was not pronounced compared to CD. In CD patients with significant steatosis, higher transaminase levels indicate subliminal hepatic inflammation, despite being within normal levels. Treatment with biologicals seems to protect CD patients from hepatic steatosis. In conclusion, we identified a high rate of hepatic steatosis in CD with alterations in transaminase levels and a potential association with biologicals.