Biomechanics of cultured hepatic cells during different steatogenic hits. (September 2019)

• Record Type: Journal Article
• Authors: Baldini, Francesca; Bartolozzi, Alice; Ardito, Martina; Voci, Adriana; Portincasa, Piero; Vassalli, Massimo; Vergani, Laura
• Is Part Of: Journal of the mechanical behavior of biomedical materials. Volume 97(2019)
• Page Start: 296
• Page End: 305
• Publication Date: 2019-09
• Subjects: NAFLD -- Non-alcoholic fatty liver disease -- FaO hepatoma cells -- Fructose -- Fatty acids -- Lipid metabolism -- Cell biomechanics -- SCFS -- Single cell force spectroscopy -- QPM -- Quantitative phase microscopy; Biomedical materials -- Periodicals; Biomedical materials -- Mechanical properties -- Periodicals; Biomedical materials; Biomedical materials -- Mechanical properties; Periodicals; Electronic journals; 610.28
• DOI: 10.1016/j.jmbbm.2019.05.036
• Languages: English
• ISSNs: 1751-6161

Abstract

Abstract: Non-alcoholic fatty liver disease (NAFLD) is a chronic liver disease often associated with overnutrition. Number and morphometry of lipid droplets (LDs) define micro vs macrovesicular steatosis, influence the morphology and function of hepatocytes and possibly their stiffness. The link between grade and features of steatosis and biomechanical properties of single hepatocytes requires deeper investigations. In vitro NAFLD models with distinct steatosis conditions were set by exposing FaO hepatoma cells to single or combined fructose (Fru), fatty acids (FA), and tumor necrosis factor (TNF)α. Single Cell Force Spectroscopy and Quantitative Phase Microscopy quantified the single cell stiffness and a series of morphometric parameters; the mRNA expression of genes involved in lipid metabolism was quantified by real-time PCR. In our models, LD size and number increased with Fru and FA as single agents, and more with combined Fru/FA (macrovesicular steatosis), while FA/TNFα combination increased LD number with a reduction in their size (microvesicular steatosis). We found that the changes in LD size and number influenced cell stiffness and morphometry as follows: (i) single cell elasticity increased in macrovesicular steatosis (maximally with combined Fru/FA); (ii) FA-induced steatosis resulted in cells thinner and larger, whereas combined FA/TNFα shrunk the hepatocytes. Taken together the data on hepatocyte biomechanics show that, in addition to extent of lipid accumulation, cell stiffness is mainly influenced by LD size, while cell morphometry directly relates to LD number. Our findings suggest that a novel mechanobiology perspective might provide future contributions in NAFLD research. Graphical abstract: Image 1 Highlights: Single cell biomechanics of in vitro models of NAFLD is assessed using a biophysical approach. Single cell stiffness is influenced by lipid droplet size in steatotic hepatocytes. Single cell morphometry directly relates to lipid droplet number in steatotic hepatocytes. Single cell elasticity might be exploited as a label-free biomarker of NAFLD severity. Mechanobiology perspective might contribute to the knowledge of NAFLD evolution.