In Situ Chemical Composition Analysis of Cirrhosis by Combining Synchrotron Fourier Transform Infrared and Synchrotron X-ray Fluorescence Microspectroscopies on the Same Tissue Section

11ABSTRACT:Liver is subject to various chronic pathologies, progressively leading to 12cirrhosis, which is associated with an increased risk of hepatocellular carcinoma. There is an 13urgent need for diagnostic and prognostic markers of chronic liver diseases and liver cancer. 14Spectroscopy-based approaches can provide an overview of the chemical composition of a 15tissue sample offering the possibility of investigating in depth the subtle chemical changes 16associated with pathological states. In this study, we have addressed the composition of 17cirrhotic liver tissue by combining synchrotron Fourier transform infrared (FTIR) 18microspectroscopy and synchrotron micro-X-rayfluorescence (XRF) on the same tissue 19section using a single sample holder in copper. This allowed investigation of the in situ 20biochemical as well as elemental composition of cells and tissues at high spatial resolution. 21Cirrhosis is characterized by regeneration nodules surrounded by annularfibrosis. 22Hepatocytes within cirrhotic nodules were characterized by high content in esters and 23sugars as well as in phosphorus and iron compared withfibrotic septa. A high heterogeneity 24was observed between cirrhotic nodules in their content in sugars and iron. Onfibrosis, synchrotron XRF revealed enrichment in 25calcium compared to cirrhotic hepatocytes. Careful scrutiny of tissue sections led to detection of the presence of microcrystals 26that were demonstrated as precipitates of calcite using synchrotron FTIR. These results demonstrated that synchrotron FTIR 27and synchrotron XRF microspectroscopies provide complementary information on the chemical composition of cirrhotic 28hepatocytes andfibrotic septa in cirrhosis.