Steatosis in non alcoholic fatty liver disease
Author(s)
Levene, Adam Phillip
Type
Thesis
Abstract
Non-alcoholic fatty liver disease is the commonest cause of chronic liver disease in developed countries.
The accurate assessment of steatosis is central to the diagnosis of non-alcoholic fatty liver disease. I compared the assessment of steatosis by histology, biochemical triglyceride assays, digital image analysis, with and without Oil Red-O staining, in mouse livers and human liver biopsies. In each case Oil Red-O digital image analysis was the most reliable technique for quantitating steatosis.
I then investigated a potential, non-invasive technique for distinguishing steatosis from steatohepatitis as only the latter causes progressive liver disease. The liver contains fluorophores which can be detected by autofluorescence spectroscopy. The fluorophore levels vary depending on the levels of oxidative stress and fibrosis within the liver. Mouse and human livers, were assessed to measure the fluorescence intensity at different wavelengths and this was compared with the histology. The probe was able to accurately identify biopsies which had inflammation and fibrosis with a high degree of sensitivity and specificity.
Autophagocytosis has recently been suggested to play a role in fat metabolism. Using liver differentiated HUH7 cells grown in normal or oleate containing media with or without Rapamycin (an autophagocytosis activator) the role of autophagocytosis was investigated. This involved examining steatosis by Oil Red-O digital image analysis, biochemical triglyceride assays, electron microscopy and confocal immunofluorescence. I concluded that activating autophagocytosis decreased the levels of steatosis within the cells.
This work has shown Oil Red-O digital image analysis is the most accurate way of assessing steatosis within the liver, that autofluorescence spectroscopy has the ability to distinguish, in real-time, isolated steatosis from steatohepatitis and that autophagocytosis has a role in fat metabolism within the liver which may be exploited therapeutically.
The accurate assessment of steatosis is central to the diagnosis of non-alcoholic fatty liver disease. I compared the assessment of steatosis by histology, biochemical triglyceride assays, digital image analysis, with and without Oil Red-O staining, in mouse livers and human liver biopsies. In each case Oil Red-O digital image analysis was the most reliable technique for quantitating steatosis.
I then investigated a potential, non-invasive technique for distinguishing steatosis from steatohepatitis as only the latter causes progressive liver disease. The liver contains fluorophores which can be detected by autofluorescence spectroscopy. The fluorophore levels vary depending on the levels of oxidative stress and fibrosis within the liver. Mouse and human livers, were assessed to measure the fluorescence intensity at different wavelengths and this was compared with the histology. The probe was able to accurately identify biopsies which had inflammation and fibrosis with a high degree of sensitivity and specificity.
Autophagocytosis has recently been suggested to play a role in fat metabolism. Using liver differentiated HUH7 cells grown in normal or oleate containing media with or without Rapamycin (an autophagocytosis activator) the role of autophagocytosis was investigated. This involved examining steatosis by Oil Red-O digital image analysis, biochemical triglyceride assays, electron microscopy and confocal immunofluorescence. I concluded that activating autophagocytosis decreased the levels of steatosis within the cells.
This work has shown Oil Red-O digital image analysis is the most accurate way of assessing steatosis within the liver, that autofluorescence spectroscopy has the ability to distinguish, in real-time, isolated steatosis from steatohepatitis and that autophagocytosis has a role in fat metabolism within the liver which may be exploited therapeutically.
Date Issued
2012
Date Awarded
2012-06
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Goldin, Robert
Anstee, Quentin
Publisher Department
Medicine
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Medicine (Research) MD (Res)