In their correspondence to Hepatology, Ehling et al. investigate elastin as a target for molecular magnetic resonance (MR) monitoring of extracellular matrix (ECM) remodeling during hepatic fibrosis.
ECM remodeling is a dynamic process occurring both during fibrogenesis, which results in net deposition, and in resolution when degradation and resorbtion occur.
Liver biopsy is still the gold standard in evaluating and staging liver fibrosis and cirrhosis. However, it is costly and invasive, with possible complications and sampling variability. Therefore, a number of direct and indirect noninvasive diagnostic tools have been investigated. In this respect, molecular MR imaging accurately reflects distribution of the ECM in the liver and may prove useful in monitoring treatment response in chronic liver disease.
The ratio between the different components of the ECM changes during progression of the disease and molecule-directed contrast agents offer potential in studying the relative changes of different proteins.
In particular, the contrast agent used in this study (elastin-specific magnetic resonance contrast agent) has already been successfully used in the assessment of atherosclerotic plaques. Ehling et al.'s study points in the direction of its usefulness in the quantification of elastin deposition in liver fibrosis, and we were delighted to read that the researchers confirmed our findings with an independent methodology, showing clear differences in elastin deposition between healthy and CCl4-treated mice. As the researchers point out, further studies are needed to evaluate dose, timing, specificity, and quantification; however, we agree that the selective or combined use of different molecular MR probes is a promising strategy for monitoring changes in accumulation of the different components of fibrous tissue.
ANTONELLA PELLICORO, PH.D.
JOHN P. IREDALE, D.M., FRCP, FMEDSCI, FRSE
MRC/UoE Center for Inflammation Research
University of Edinburgh