Review for 10.1186/s12876-020-01194-2 (2020)

Reviewer’s report
Title: Fructo-Oligosaccharides Ameliorate Steatohepatitis, Visceral Adiposity, and Associated
Chronic Inflammation via Increased Production of Short-Chain Fatty Acids in a Mouse Model of
Non-alcoholic Steatohepatitis
Version: 0 Date: 27 Nov 2019
Reviewer: Emanuele Albano
Reviewer's report:
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The manuscript by Takai and co-workers investigates the effects of fructo-oligosaccharides (FOS) on
steatohepatitis and visceral adiposity in a model of NASH based on the induction of over-feeding by
the  administration  of  monosodium  glutamate  (MSG)  to  newborn  C57BL/6J  mice.   The  authors
observed that FOS treatment improved steatosis, inflammation and hepatocyte ballooning in the liver of
mice with NASH. These effects were associated with a lowering in the hepatic mRNA expression of
fatty acid synthase and glycerol-3-phosphate acyltransferase. Furthermore, FOS inhibited adipocyte
enlargement and macrophage recruitment in epididymal fat in parallel with changes in gut microbiota
composition and increased fecal concentrations of short chain fatty acids (SCFA) suggesting that FOS
action  on  dysbiosis  might  influence  the  development  of  metabolic  derangements  leading  to
steatohepatitis.
The work is interesting and has a potential translational impact. However, additional data are required
to support the author's conclusions. The following points need attention:
a) Figure 1 shows that FOS supplementation improves body weight as well as epididymal fat expansion
and inflammation. Nonetheless, the effects on adipose tissue require a better characterization from the
metabolic  and  inflammatory point of view  by measuring  glucose  tolerance  and insulin  response,
assessing adipose tissue expression of pro-inflammatory cytokines and the production of adipokines.   
b) The characterization of FOS action on NASH is also insufficient. Liver triglyceride content need to
be shown along with the liver or circulating levels of pro-inflammatory cytokines.
c) The authors have previously shown that FOS supplementation improves intestinal barrier function in
MCD fed mice.   It would be important to evaluate how much such an effect accounts for ameliorating
NASH in this model.  The measurement of circulating LPS levels can address this issue.
d) It is interesting that FOS reduced inflammatory cells infiltration in the adipose tissue, but the data
presented are insufficient to substantiate histology. Flow cytometry should be used to show the changes
in the prevalence of F4/80+/CD11b+ macrophages and of B and T lymphocytes.  Furthermore, M1
macrophages are identified as F4/80+/CD11b+/Ly6Chigh cells.  The use of CD11c is not a suitable
marker.
e) The overall impact of the work would be increased by investigating whether FOS supplementation is
also effective in ameliorating dybiosis and liver alterations with more widely used model of NASH
such as the high fat western diet.   
Are the methods appropriate and well described?
If not, please specify what is required in your comments to the authors.
Yes
Does the work include the necessary controls?
If not, please specify which controls are required in your comments to the authors.
Yes
Are the conclusions drawn adequately supported by the data shown?
If not, please explain in your comments to the authors.
Yes
Are you able to assess any statistics in the manuscript or would you recommend an
additional statistical review?
If an additional statistical review is recommended, please specify what aspects require further
assessment in your comments to the editors.
I am able to assess the statistics
Quality of written English
Please indicate the quality of language in the manuscript:
Needs some language corrections before being published
Declaration of competing interests
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