PONE-D-19-22988

Effects of tetracycline on myocardial infarct size in obese rats with chemically-induced colitis

PLOS ONE

Dear Dr. Galagudza,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Partly

Reviewer #2: Partly

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: No

Reviewer #2: Yes

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #2: Yes

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5. Review Comments to the Author

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Reviewer #1: Borshchev and colleagues determined the effects of tetracycline (TTC) on myocardial infarct size in obese rats following chemically-induced colitis (CIC). To accomplish this, authors used a single dose of rectal administration of 3 % acetic acid to the rats that induced CIC. Overall interesting manuscript, needs some additional clarification and precise interpretation of infarction area and microbiome results.

1. Add detailed information of age and sex of rats that were used in the presented study.

2. Infarct size is variable outcome depending on the color density therefore need additional clarification on this aspect.

3. Most important, the infarct size not infarct area is measured and measured only ex-vivo hearts, instead of in-vivo.

4. Does the provided ex-vivo changes align with in-vivo changes in the literature or any previosu results, please discuss.

5. Elaborate microbiome results, in contest of inflammation and possible dysregulation.

6. Measured short chain fatty acids are determined in serum, however in cardiac tissue will be of interest to determine the impact on infarct size/area.

7. Provide rationale for short chain fatty acids measurements, in context of micriobiome.

8. For microbiome data integration with cardiac outcome refer particularly extensive statistical analyses of intestinal microbime data - PMCID: PMC6463911

9. This multilayered study needs clarified presentation which lacking in the entire manuscript.

10. In discussion suggest, how obesity impacted the overall cardiac dysregulation of metabolism in-vivo tissue rather than ex-vivo.

Reviewer #2: In their manuscript, Borshchev et al. investigated the effect of the gut microbiota on the extent of myocardial injury after ischemia. They observed a potentially beneficial effect of tetracycline (TTC)-mediated alteration of distinct intestinal bacteria in rats fed a standard diet whereas these effects were abolished in high fat diet induced obesity and chemically induced colitis. Overall, the novelty of the current study is limited since cardioprotective effects of TTC in an experimental myocardial infarction model has been previously postulated. Moreover, it remains unclear why the authors treated chemically induced colitis to investigate TTC-related effects on ischemic myocardial injury.

Further major points that need to be clarified are as follows:

1. Please explain why despite differences in the extent of myocardial injury upon treatment with tetracycline, the hemodynamic parameters are not affected.

2. What are putative underlying mechanisms of TTC-mediated cardiac protection in lean mice and which mechanisms are dysregulated leading to detrimental effects of TTC in chemical induced colitis.

3. Measuring SCFAs in the plasma is not expedient, since most of the SCFAs are metabolized in the liver before reaching the circulation. Thus, to assess changed in SCFA production, it is recommended to measure SCFAs in the feces. Protective effects of SCFAs are considered to be based on local paracrine mechanisms in the intestine (such as intestinal immune homeostasis) with secondary systemic consequences.

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Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

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PONE-D-19-22988R1

Effects of tetracycline on myocardial infarct size in obese rats with chemically-induced colitis

PLOS ONE

Dear Dr. Galagudza,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript with the small changes in the text suggested by the two reviewers.

We would appreciate receiving your revised manuscript by Dec 13 2019 11:59PM. When you are ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter.

To enhance the reproducibility of your results, we recommend that if applicable you deposit your laboratory protocols in protocols.io, where a protocol can be assigned its own identifier (DOI) such that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols

Please include the following items when submitting your revised manuscript:

• A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). This letter should be uploaded as separate file and labeled 'Response to Reviewers'.
• A marked-up copy of your manuscript that highlights changes made to the original version. This file should be uploaded as separate file and labeled 'Revised Manuscript with Track Changes'.
• An unmarked version of your revised paper without tracked changes. This file should be uploaded as separate file and labeled 'Manuscript'.

Please note while forming your response, if your article is accepted, you may have the opportunity to make the peer review history publicly available. The record will include editor decision letters (with reviews) and your responses to reviewer comments. If eligible, we will contact you to opt in or out.

We look forward to receiving your revised manuscript.

Kind regards,

Michael Bader

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: Majority comments answered, failed to update text in terms of recent changes of microbiome in context of obesity which is common comorbidity in patients, add this specific references suggested in original first critiques/comments.

Reviewer #2: The authors have satisfactorily discussed my previous points. Please address in the discussion section that the changes in myocardial infarct size were not reflected by changes in performance of the isolated heart subjected to ischemia-reperfusion.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

Effects of tetracycline on myocardial infarct size in obese rats with chemically-induced colitis

PONE-D-19-22988R2

Dear Dr. Galagudza,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

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With kind regards,

Michael Bader

Academic Editor

PLOS ONE

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