Reviewer ’s report  
 
Title: Retinoid and Carotenoid Status in Serum and Liver Among Patients at High -Risk for Liver 
Cancer  
 
 
Version: 0 Date: 26 Nov 2015  
 
 
Reviewer: Eleonora Patsenker  
 
 
Reviewer's report:  
 
The present study aimed to identify key predictors of serum antioxidant levels in patients with 
HCV, to examine the relationship between retinoid/carotenoid concentrations in serum and 
hepatic tissue, to quantify the association between systemic measures of oxidative stress and 
antioxidant status, and to examine the relationship between retinoids and stel late cell activation. 
The authors found a significant inverse association between serum retinol, lycopene, and RBP4 
concentrations with fibrosis stage. Serum β -carotene and lycopene were strongly associated with 
their tissue levels. There was a weak downwa rd trend of tissue retinyl palmitate with increasing 
fibrosis stage. Tissue retinyl palmitate was inversely and significantly correlated with hepatic 
αSMA expression. Urinary isoprostanes levels were inversely correlated with serum retinol, β -
carotene, and  RBP4. The authors concluded that a decrease in serum retinol, β -carotene, and 
RBP4 is associated with early stage HCV. Retinoid and carotenoid levels decline as disease 
progresses, and our data suggest that this decline occurs early in the disease process , even before 
fibrosis is apparent. Measures of oxidative stress are associated with fibrosis stage and 
concurrent antioxidant depletion. Vitamin A loss is accompanied by stellate cell activation in 
hepatic tissue.  
 
1) The study is of potential interest, but very descriptive and lacking mechanistic insights. 
All the conclusions made are purely speculative and has to be either excluded or 
supported experimentally.  
 
2) Was there any reason for using particularly HCV cohort? As no direct relation of 
retinoid s with specific viral infection is shown or known, and possibly, rather secondary 
complication events (hepatic fibrosis, inflammation and fatty liver) in chronic liver 
diseases are critical in triggering (or being triggered) by retinoid metabolism. Has to be 
mentioned or explained.  
3) In control and No Fibrosis groups there is a prevalence of patients with BMI index 
≥30: 41% and 44% vs 23% and 35% in mild -to-severe fibrosis groups. Might it affect the 
results obtained? As it's known that there is a tight r elationships between obesity, fat and 
retinoid acid, and these cohorts might not be quite comparable due to the 
impaired/differentially regulated fat/retinoids metabolism?  
 
       
 
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 supporte d by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an a dditional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
I recommend additional statistical review  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from 
an organisation that may in any way gai n or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the fu ture?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you 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 interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I  declare that I have no competing interests' 
below.  If your reply is yes to any, please give details below.  
 
I dec lare that I have no competing interests.  
 
I agree to the open peer review policy of the journal. I understand 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 website along with the authors'  
responses. I agree for my report to be made available under an Open Access C reative Commons  
CC-BY licens e (http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments  
which I do not wish to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
Reviewer ’s report  
 
Title: Retinoid and Carotenoid Status in Serum and Liver Among Patients at High -Risk for Liver 
Cancer  
 
 
Version: 0 Date: 26 Nov 2015  
 
 
Reviewer: Eleonora Patsenker  
 
 
Reviewer's report:  
 
The present study aimed to identify key predictors of serum antioxidant levels in patients with 
HCV, to examine the relationship between retinoid/carotenoid concentrations in serum and 
hepatic tissue, to quantify the association between systemic measures of oxidative stress and 
antioxidant status, and to examine the relationship between retinoids and stel late cell activation. 
The authors found a significant inverse association between serum retinol, lycopene, and RBP4 
concentrations with fibrosis stage. Serum β -carotene and lycopene were strongly associated with 
their tissue levels. There was a weak downwa rd trend of tissue retinyl palmitate with increasing 
fibrosis stage. Tissue retinyl palmitate was inversely and significantly correlated with hepatic 
αSMA expression. Urinary isoprostanes levels were inversely correlated with serum retinol, β -
carotene, and  RBP4. The authors concluded that a decrease in serum retinol, β -carotene, and 
RBP4 is associated with early stage HCV. Retinoid and carotenoid levels decline as disease 
progresses, and our data suggest that this decline occurs early in the disease process , even before 
fibrosis is apparent. Measures of oxidative stress are associated with fibrosis stage and 
concurrent antioxidant depletion. Vitamin A loss is accompanied by stellate cell activation in 
hepatic tissue.  
 
1) The study is of potential interest, but very descriptive and lacking mechanistic insights. 
All the conclusions made are purely speculative and has to be either excluded or 
supported experimentally.  
 
2) Was there any reason for using particularly HCV cohort? As no direct relation of 
retinoid s with specific viral infection is shown or known, and possibly, rather secondary 
complication events (hepatic fibrosis, inflammation and fatty liver) in chronic liver 
diseases are critical in triggering (or being triggered) by retinoid metabolism. Has to be 
mentioned or explained.  
3) In control and No Fibrosis groups there is a prevalence of patients with BMI index 
≥30: 41% and 44% vs 23% and 35% in mild -to-severe fibrosis groups. Might it affect the 
results obtained? As it's known that there is a tight r elationships between obesity, fat and 
retinoid acid, and these cohorts might not be quite comparable due to the 
impaired/differentially regulated fat/retinoids metabolism?  
 
       
 
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 supporte d by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an a dditional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
I recommend additional statistical review  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from 
an organisation that may in any way gai n or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the fu ture?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you 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 interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I  declare that I have no competing interests' 
below.  If your reply is yes to any, please give details below.  
 
I dec lare that I have no competing interests.  
 
I agree to the open peer review policy of the journal. I understand 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 website along with the authors'  
responses. I agree for my report to be made available under an Open Access C reative Commons  
CC-BY licens e (http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments  
which I do not wish to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
Please review this paper.
user
Reviewer ’s report  
 
Title: Retinoid and Carotenoid Status in Serum and Liver Among Patients at High -Risk for Liver 
Cancer  
 
 
Version: 0 Date: 26 Nov 2015  
 
 
Reviewer: Eleonora Patsenker  
 
 
Reviewer's report:  
 
The present study aimed to identify key predictors of serum antioxidant levels in patients with 
HCV, to examine the relationship between retinoid/carotenoid concentrations in serum and 
hepatic tissue, to quantify the association between systemic measures of oxidative stress and 
antioxidant status, and to examine the relationship between retinoids and stel late cell activation. 
The authors found a significant inverse association between serum retinol, lycopene, and RBP4 
concentrations with fibrosis stage. Serum β -carotene and lycopene were strongly associated with 
their tissue levels. There was a weak downwa rd trend of tissue retinyl palmitate with increasing 
fibrosis stage. Tissue retinyl palmitate was inversely and significantly correlated with hepatic 
αSMA expression. Urinary isoprostanes levels were inversely correlated with serum retinol, β -
carotene, and  RBP4. The authors concluded that a decrease in serum retinol, β -carotene, and 
RBP4 is associated with early stage HCV. Retinoid and carotenoid levels decline as disease 
progresses, and our data suggest that this decline occurs early in the disease process , even before 
fibrosis is apparent. Measures of oxidative stress are associated with fibrosis stage and 
concurrent antioxidant depletion. Vitamin A loss is accompanied by stellate cell activation in 
hepatic tissue.  
 
1) The study is of potential interest, but very descriptive and lacking mechanistic insights. 
All the conclusions made are purely speculative and has to be either excluded or 
supported experimentally.  
 
2) Was there any reason for using particularly HCV cohort? As no direct relation of 
retinoid s with specific viral infection is shown or known, and possibly, rather secondary 
complication events (hepatic fibrosis, inflammation and fatty liver) in chronic liver 
diseases are critical in triggering (or being triggered) by retinoid metabolism. Has to be 
mentioned or explained.  
3) In control and No Fibrosis groups there is a prevalence of patients with BMI index 
≥30: 41% and 44% vs 23% and 35% in mild -to-severe fibrosis groups. Might it affect the 
results obtained? As it's known that there is a tight r elationships between obesity, fat and 
retinoid acid, and these cohorts might not be quite comparable due to the 
impaired/differentially regulated fat/retinoids metabolism?  
 
       
 
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 supporte d by the data shown?  
If not, please explain in your comments to the authors.  
 
No 
 
Are you able to assess any statistics in the manuscript or would you recommend an  
additional statistical review?  
If an a dditional statistical review is recommended, please specify what aspects require further  
assessment in your comments to the editors.  
 
I recommend additional statistical review  
 
Quality of written English  
Please indicate the quality of language in the manuscript:  
 
Acceptable  
 
Declaration of competing interests  
Please complete a declaration of competing interests, considering the following questions:  
 
1. Have you in the past five years received reimbursements, fees, funding, or salary from 
an organisation that may in any way gai n or lose financially from the publication of this  
manuscript, either now or in the future?  
 
2. Do you hold any stocks or shares in an organisation that may in any way gain or lose  
financially from the publication of this manuscript, either now or in the fu ture?  
 
3. Do you hold or are you currently applying for any patents relating to the content of the  
manuscript?  
 
4. Have you 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 interests in relation to this paper?  
 
If you can answer no to all of the above, write 'I  declare that I have no competing interests' 
below.  If your reply is yes to any, please give details below.  
 
I dec lare that I have no competing interests.  
 
I agree to the open peer review policy of the journal. I understand 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 website along with the authors'  
responses. I agree for my report to be made available under an Open Access C reative Commons  
CC-BY licens e (http://creativecommons.org/licenses/by/4.0/ ). I understand that any comments  
which I do not wish to be included in my named report can be included as confidential comments  
to the editors, which will not be published.  
 
I agree to the open peer review policy of the journal  
assistant