Review for 10.1186/s12876-017-0627-4 (2017)

Reviewer ’s report  
 
Title: Anti-fibrogenic effect of PPAR -γ agonists in human intestinal  myofibroblasts  
 
Version: 0 Date: 28 Dec 2016  
 
Reviewer: Adrian Cummins  
 
Reviewer's report:  
 
This study shows a mechanism for inhibition of fibrogenesis in cultured fibrobasts.  
 
 
Title: I found the title very confusing and obfuscati ng. The authors are trying to get too much 
across -ie, that they induced activation of fibroblasts by TGFbeta, that they used cultured human 
intestinal (colonic) fibroblasts and this activation was inhibited by down regulation of Akt using 
PPAR -gamma agonis ts. The authors need to decide what is their main message. Could this be 
simplified to something like: 'PPAR -gamma agonists reduce markers of fibrogenesis in cultured 
colonic fibroblasts'.  
 
 
I found the general style of the paper was written with emphasis o n methodology (an increasing 
tendency these days) and this clouded the true message with a tendency to an obtuse title, 
distractions, and a Results section that had commentary that should be placed in the Discussion.  
 
 
The Abstract has far too many abbrevia tions. An unfamiliar reader has to decode each 
abbreviation. What and why were LY294002 and GW9662 used? There seems an imbalance that 
nearly all the data relate to showing that TGFbeta activates markers of fibrogenesis which are 
already known in other tis sues. I would not make method the subject of a sentence but the 
process examined, eg 'PPAR -gamma agonists down regulated fibrogenesis, as shown by 
inhibition of Akt and Smad2 phosphorylation', rather than 'Inhibition of Akt and Smad2 
phosphorylation by bot h PPAR -gamma agonists resulted in anti -fibrogenic effects.  
 
 
I think the Introduction can be shortened and made more direct eg para 2 lines 23 -51 goes into 
great detail of Smad dependent and independent pathways, which is a distraction. This gets 
quoted again over the page (page 7, para 1 , lines 14 -18).  
 
 
Do the au thors want to consider whether there might be difference of fibroblasts between those 
isolated from the small versus the large intestine. Fibrosis is mainly a problem in the small 
intestine, but the fibroblasts for this study came from the large intestine.  
 
 
Statistical analysis: I don't know if the Journal has a policy but variation of data around central 
tendency should be given as SD rather than SEM. If the ANOVA analysis yields no significant 
difference then, it is not justified to proceed onto Tukey's m ultiple comparison test as in Results 
(page 11, para 3, lines 57 -60. Presumably the criteria of P<0.05 relates to an experimentwise 
probability and individual paired comparisons will have lower P values.  
 
 
The Results section needs considerable editing.  I  would not use the plural of 'effects' rather say 
'Effect of PPAR -gamma agonists … '. I would separate commentary on the results to the 
Discussion.  I would change Subheadings from statements of deduced fact to intention of method 
ie 'TGF -beta induced expr ession of alpha smooth actin … ' to 'Effect of  PPAR -gamma agonists 
on myofibroblasts'. I would keep Results to just that and not repeat that 'alpha -SMA is a key 
activation marker of myofibroblasts, which is induced by TGFbeta' (page 12, para 2, lines 13 -14. 
This was already quoted in the Introduction (Page 7, para1, lines 13 -14). I would change syntax 
construction with less emphasis on methods. Once again I would not always made the subject of 
the sentence the method.  I would edit out modifying emotional adverbs eg remarkably inhibited, 
notably lack, I would let the data convince the reader -they do not have to be cajoled.  
 
 
I would be consistent with abbreviations (Figs or Figures, which?). Some material is just 
commentary in the Results and should go to Di scussion eg Page 12 para 3, lines eg 'Formation of 
stress fibers (actin filaments) in myofibroblasts exerts a contractile  activity, and TGFbeta1 also 
enhances the stress fiber formation and contractile fiber formation myyofibroblasts.' Thus, the 
Results n eed to be pruned and made pertinent.  
 
 
I think the Discussion needs to lift its intellectual plane. Para 1 can be safely removed removed 
entirely. I like the second half of para 2 (lines 45 to 60) as it summarises the whole study and 
should set the scene fo r a detailed Discussion. Para 1 (page 17) fails getting caught up with 
methology except for the last two sentences (lines 20/21 to 25). I think the limitations of this 
work should be briefly discussed ie this was an in vitro study.  
 
 
The immunofluorescence photomicrographs are almost impossible to decipher.  A cynic would 
say they emphasise contrast over resolution and can hide any artifact in the background.  I would 
prefer a single or two big photomicrographs and perhaps have the others as Supplementary 
photomicrographs.  
 
 
The point size of the legends and axis markers of the Figures should be increased as they will be 
very small in the final manuscript.  
 
 
 
 
 
Minor issues:  
 
Page 1, line 25: Capitalize. Institute of Basic medical sciences  
 
 
Page 7, para 3, lines  53, 54. Capitalize. Cayman chemical & Cell signalling and similarly page 
10, para 1 line 25, 28, and page 10, para 1, line 38 Santa Cruz biotechnology  
 
 
 
 
 
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 aspe cts 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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