Raman imaging of rat nonalcoholic fatty liver tissues reveals distinct biomolecular states

Abstract

An essential challenge in diagnosing states of nonalcoholic fatty liver disease (NAFLD) is the early prediction of progression from nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH) before the disease progresses. Histological diagnoses of NAFLD rely on the appearance of anomalous tissue morphologies, and it is difficult to segment the biomolecular environment of the tissue through a conventional histopathological approach. Here, we show that hyperspectral Raman imaging provides diagnostic information on NAFLD in rats, as spectral changes among disease states can be detected before histological characteristics emerge. Our results demonstrate that Raman imaging of NAFLD can be a useful tool for histopathologists, offering biomolecular distinctions among tissue states that cannot be observed through standard histopathological means.

Discrimination of lipid composition and cellular localization in human liver tissues by stimulated Raman scattering microscopy

“…The SRS microscopy platform can be used to test specific hypotheses of lipotoxicity and may have potential clinical applications in the future if SRS "markers" associated with clinical outcomes are identified. [8][9][10] Our work has some limitations. We only focused on free cholesterol, cholesterol esters (saturated and unsaturated), and TAGs (of different saturation levels) in this work.…”

“…The SRS microscopy platform can be used to test specific hypotheses of lipotoxicity and may have potential clinical applications in the future if SRS “markers” associated with clinical outcomes are identified. 8 – 10 …”

“…[1][2][3][4][5] Raman microscopy is a technique that has been applied to NAFLD only recently and has great potential in further clarifying the role of lipotoxicity in NASH because it can characterize both the type and spatial localization of relevant lipid molecules. [6][7][8][9][10] Specifically, Minamikawa et al 6 applied Raman microscopy to visualize the distribution of lipid droplets in hepatocytes in NASH model mice liver tissues and demonstrated its capability of characterizing the molecular features of accumulated microvesicular and macrovesicular lipid droplets. Takemura et al 7 utilized spontaneous Raman microscopy to evaluate steatosis and retinol content in rat liver tissues at the nascent state of NAFLD.…”

“…Diagnosing states of NAFLD in mice models can also be achieved by Raman micro-spectroscopy combined with machine learning algorithms. 8 – 10 Our group has been involved in the development of hyperspectral stimulated Raman scattering (hsSRS) microscopy as an advancement over traditional Raman microscopy, which offers several advantages such as increased imaging sensitivity and acquisition speed. 11 – 14 Moreover, the SRS signal has a linear dependence on the analyte concentration, making it an ideal tool for quantitative chemical composition analysis.…”

Bioinspired Bioinks for the Fabrication of Chemomechanically Relevant Standalone Disease Models of Hepatic Steatosis

“…[39][40][41] However, the accumulation of lipids that characterizes NAFLD enhances the viscous behavior of the surrounding tissue. [41][42][43] This peculiar aspect is due to the viscosity of triglycerides being significantly higher than the one of water. [44] The bioinks supplemented with sodium oleate exert a mild cytotoxic effect on cultured cells, without impairing their ability to proliferate, starting from 5 days from the production of the cell-laden constructs.…”