Non-invasive liver fibrosis assessment correlates with collagen and elastic fiber quantity in patients with hepatitis C virus infection.

Aim: Elastic fiber deposition is a cause of irreversibility of liver fibrosis. However, to date, its relevance to clinical features has not yet been clarified. This study aimed to clarify the correlation between non-invasive markers of fibrosis and fiber quantity, including elastic fiber, obtained from computational analysis.

Methods: This retrospective study included 270 patients evaluated by non-invasive liver fibrosis assessment prior to liver biopsy. Of these patients, 95 underwent magnetic resonance elastography (MRE) and 244 were assessed with Wisteria floribunda agglutinin-positive Mac-2 binding protein (WFA -M2BP). Using whole-slide imaging of Elastica van Gieson-stained liver biopsy sections, the quantity of collagen, elastin, and total fiber (elastin + collagen) was determined.

Results: The total fiber quantity showed significant linear correlation with fibrosis stage F0-F4. Collagen fiber quantity increased from stage F0 to F4, whereas elastic fiber quantity increased significantly only from stage F2 to F3. Spearman's rank correlation test revealed that non-invasive liver fibrosis assessment significantly correlates with each fiber quantity, including correlation between total fiber quantity and the Fibrosis-4 (FIB-4) index (r = 0.361, P < 0.001), WFA -M2BP values (r = 0.404, P < 0.001), and liver stiffness value by MRE (r = 0.615, P < 0.001). Receiver operating characteristic (ROC) curve analyses revealed that the area under ROC for predicting higher elastic fiber (>3.6%) is 0.731 by FIB-4 index, 0.716 by WFA -M2BP, and 0.822 by liver stiffness by MRE.

Conclusion: Liver fibrosis correlates with fiber quantity through non-invasive assessment regardless of fiber type, including elastic fiber. Moreover, MRE is useful for predicting high amounts of elastic fiber.