Review for 10.1186/s12876-020-01248-5 (2020)

Reviewer ’s report  
 
Title: 25(OH) D3 alleviate liver NK cytotoxicity in acute but not in chronic fibrosis model of  
BALB/c mice due to modulations in vitamin D receptor  
 
Version: 2 Date: 08 Jan 2020  
 
Reviewer: Lindsey Kennedy  
 
Reviewer's report:  
 
In this manuscript, the authors claim that vitamin D treatment is able to reduced NK cell 
cytotoxicity in the acute, but not chronic, model of liver fibrosis. Mainly, they believe that during 
the acute fibrosis setting  the vitamin D increase in NK cell cytotoxicity leads to decreased 
hepatic stellate cell (HSC) activation. However, during chronic fibrosis vitamin D worsens the 
fibrotic effect. The conclusions from the paper are not fully supported by the work.  
 
1. Staining for NK cells should have been performed.  
 
2. Appropriate markers of NK cell cytotoxicity and activation were not used. Better 
characterization of the NK cells should have been performed.  
 
3. Staining for VDR should have been performed in the liv er. It is unclear where the vitamin 
D/VDR interaction is occurring.  
 
4. The authors did not fully evaluate VDR downstream signaling to show changes in activation.  
 
5. Vitamin D strongly regulates intestinal function and this may be a reason the authors have 
different outcomes in acute versus chronic settings.  
 
6. The reasoning as to why there are worse conditions for vitamin D in the chronic fibrosis 
setting is unclear and was not fully explored or explained.  
 
7. The authors only looked at alpha -SMA as a fibrot ic marker, but other factors should have been 
evaluated.  
 
8. HSCs should have been stained in the model.  
 
 
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.  
 
No 
 
Are you able to assess any statistics in t he manus cript or would you recommend an 
additional statistical review?  
If an additional statistical review is recommended, please speci fy what aspects require further 
assessment in your comments to the editors.  
 
I am able to assess the s tatistics  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Needs some language corrections before being published  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following que stions:  
 
1. Have you in the past five years received reimbursements, f ees, funding, or salary from an 
organisation that may in any way gain or lose financial ly from the publication of this 
manuscript, either now or in the future?  
 
2. Do you hold any stocks o r shares in an organisation t hat may in any way gain or lose 
financially from the publication of this manuscript, either now or in the future?  
 
3. Do you hold or are you currently applying for any patents  relating to the content of the 
manuscript?  
 
4. Have y ou received reimbursements, fees, funding, or salary from an organization that 
holds or has applied for patents relating to the content of the manuscript?  
 
5. Do you have any other financial competing interests?  
 
6. Do you have any non -financial competing in terests in relation to this paper?  
 
If you can answer no to all of the above, write 'I declare that I have  no competi ng interests' 
below. If your reply is yes to any, please give details below.  
 
I have no competing interests  
 
I agree to the open peer review policy of the journal. I understan d that my name will be included 
on my report to the authors and, if the manuscript is accepted for publication, my named report  
including any attachments I upload will be posted on the websi te along with the authors' 
responses. I agree for my report to be made available under an Open Access Creative Commons  
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which I do not wish to be included in my name d report can be in cluded as confidential comments 
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal