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MRE detects liver fibrosis in patients with deficient alpha-1 antitrypsin

In a pilot prospective study, magnetic resonance elastography identified the presence of liver fibrosis in adults with deficient alpha-1 antitrypsin, suggesting it may be an accurate noninvasive biomarker for patients with liver disease and this deficiency.   

“This is the first study of advanced [magnetic resonance elastography] in a rare disease called alpha-1 antitrypsin deficiency,” Rohit Loomba, MD, MHSc, professor of medicine in the division of gastroenterology, University of California San Diego School of Medicine, told Healio.com/hepatology. “Most patients have lung disease and there is no clear way of detecting who has liver disease so noninvasive assessment such as the MRE is critical for this disease.”

Rohit Loomba

Loomba and colleagues compared demographic and imaging data of 11 patients with homozygous (ZZ) alpha-1 antitrypsin (AAT) deficiency — a genetic disease that can lead to emphysema, cirrhosis and hepatocellular carcinoma in adults and neonatal hepatitis — with 11 normal controls and 11 patients with biopsy-proven nonalcoholic fatty liver disease.

The researchers quantified histological fibrosis using a modified Ishak 6-point scale and liver stiffness by magnetic resonance elastography (MRE). Diagnostic performance of MRE for the detection of fibrosis was assessed via receiver operating characteristic (ROC) analysis.

“A key challenge is the absence of an accurate noninvasive diagnostic tool to diagnose liver disease in individuals with AAT deficiency, especially in asymptomatic adults who may have lung disease and are receiving enzyme replacement. The significance of abnormal liver tests in ZZ patients is unclear. …,” the researchers wrote.

Results showed alanine aminotransferase levels were similar within the normal-control group (16.4 ± 4) and AAT groups (23.5 ± 10.8). However, ALT was significantly lower in the AAT group compared with patients in the NAFLD group (P < 0.05). This remained even after adjustment of fibrosis stage (P = .0172).

“Our data show serum biomarkers most commonly elevated in individuals with other forms of metabolic liver disease, such as ALT and [gamma-glutamyl transferase], are not elevated in individuals with AAT deficiency liver disease,” the researchers wrote.

MRE-estimated stiffness had an area under the ROC curve of 0.9 (P < .0001) for the detection of fibrosis. An MRE threshold 3 kPa or greater yielded 88.9% accuracy, as well as an 80% sensitivity and 100% specificity rate to detect any fibrosis.

“This pilot study provides novel advanced noninvasive characterization of fibrosis in patients with AAT deficiency and contemporaneous liver biopsy as gold standard. …Future multicenter studies with larger sample sizes are needed to determine the accuracy of MRE in classifying stage of fibrosis, predicting advanced fibrosis and monitoring progression or response to treatment in AAT deficient patients,” the researchers concluded. – by Melinda Stevens

Disclosure: The researchers report no relevant financial disclosures.