Autofluorescence study of human steatotic liver

Background/Objective: The increasing demand of livers for transplantation leads to accept ‘‘marginal livers’’, such as the steatotic ones, provided that the lipid accumulation does not exceed a mild-to-moderate degree. Steatosis is a failure risk factor, since it increases the susceptibility to ischemia-reperfusion injures induced by conventional preservation procedures. Autofluorescence already proved to be an intrinsic parameter of liver morphofunctional properties, depending on the nature, amount and distribution of endogenous fluorophores involved in tissue metabolism and structure. Aim of the work is to characterize the influence of lipids accumulation on human liver autofluorescence properties. Study Design: Cryostatic sections, from frozen liver samples preserved at _808C, were submitted to autofluorescence microspectrofluorimetry and imaging analysis (exc. 366 nm). Parallel sections were H&E stained for diagnosis. Preliminary autofluorescence analysis was also performed on bulk tissue specimens via fiber-optic spectrophotometer. Results: In steatotic livers the typical vacuoles of lipids accumulation exhibited an intense emission in the 450–570 nm region, and under continuous irradiation showed a much faster photofading process than the surrounding normal parenchyma. A correlated analysis of signal amplitude, photofading kinetics and spectral shape of autofluorescence emission provides information of the degree of lipids accumulation. Conclusions: Autofluorescence analysis proved to be an exploitable approach to study lipids accumulation in liver. The development of suitable algorithms calculation would provide the basis to set up real-time techniques for steatosis assessment.