Review for 10.1186/s12876-017-0652-3 (2017)

Reviewer ’s report  
 
Title:  Efficacy of Glutathione for the Treatment of Nonalcoholic Fatty Liver Disease: An Open -
label, Single -arm, Multicenter, Pilot Study  
 
Version: 0 Date: 11 Apr 2017 
 
Reviewer:  Adil Mardinoglu  
 
Reviewer’s report:  
 
Honda et all evaluate d 34 NAFLD patients diagnosed by ultrasonography and performed a 
lifestyle intervention (diet and exercise), beginning 3 months before GSH treatment, followed by 
treatment with GSH (300 mg/day) for 4 months. The authors evaluated the clinical parameters 
and quantified liver fat and fibrosis before and after GSH treatment. The primary outcome of this 
study was defined based on the change in alanine aminotransferase (ALT) concentrations.  
 
The authors reported that twenty -nine patients finished the protocol an d ALT levels were 
significantly decreased by treatment with GSH for 4 months. In addition, triglycerides, non -
esterified fatty acids, and ferritin levels were also decreased by GSH treatment. Following 
dichotomization of ALT responders based on a median 12 .9% decrease from baseline, the 
authors found that ALT responders were younger in age and did not have diabetes or had mild 
diabetes.  
 
In my opinion, the study is quite interesting and the methods used in the study are appropriate. 
However, I have number o f concerns about the study.  
 
1) The authors supplemented GSH rather than precursors. This is not in line with the literature 
knowledge. GSH can be degraded in the stomach and it may not reach the liver. The authors did 
not quantify the level of GSH in the plasma or liver of the subjects.  
 
2) It is quite interesting that the level of GGT, γ -glutamyl transpeptidase is not changed after 
GSH supplementation.  
 
3) Recently, serine has been defined as the limiting substrate in NAFLD patients. 
http://msb.embopress. org/content/13/3/916. The authors should discuss the paper since it has 
been showed that supplementation of the serine; precursor for GSH decreased the liver fat of the 
subjects. There are also papers about the glycine and N -Acetly cysteine supplementation  in 
NAFLD patients.  
 
4) I also suggest the authors to include detailed discussion about the potential mechanism 
considering the previously published papers.  
 
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 nec essary 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:  
 
Acceptable  
 
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