Sevoflurane versus ketamine+diazepam anesthesia for assessing systemic and hepatic hemodynamics in rats with non-cirrhotic portal hypertension

José Ignacio Fortea; Marta Puerto; Carolina Fernández-Mena; Iris Asensio; María Arriba; Jorge Almagro; Juan Bañares; Cristina Ripoll; Rafael Bañares; Javier Vaquero

doi:10.1371/journal.pone.0233778

Peer Review History

Original SubmissionMarch 22, 2020
14 Apr 2020 Decision Letter - Matias A Avila, Editor PONE-D-20-08262 Sevoflurane versus ketamine+diazepam anesthesia for assessing systemic and hepatic hemodynamics in rats with portal hypertension. PLOS ONE Dear Dr Vaquero, 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. We would appreciate receiving your revised manuscript by May 29 2020 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, Matias A Avila, Ph.D. Academic Editor PLOS ONE Journal Requirements: When submitting your revision, we need you to address these additional requirements: 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at http://www.plosone.org/attachments/PLOSOne_formatting_sample_main_body.pdf and http://www.plosone.org/attachments/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for including your ethics statement: "All studies complied with the Guide for the Care and Use of Laboratory Animals (NIH publication no. 86-23, revised 1985) and with local regulations (PROEX # 272/15)." a.) Please amend your current ethics statement to include the full name of the ethics committee that approved your specific study. b.) Please amend your current ethics statement to confirm that your named ethics committee specifically approved this study. For additional information about PLOS ONE submissions requirements for ethics oversight of animal work, please refer to http://journals.plos.org/plosone/s/submission-guidelines#loc-animal-research Once you have amended this/these statement(s) in the Methods section of the manuscript, please add the same text to the “Ethics Statement” field of the submission form (via “Edit Submission”). 3. At this time, we request that you please report additional details in your Methods section regarding animal care, as per our editorial guidelines: (1) Please state the source and number of mice used in the study (2) Please describe the post-operative care received by the animals, including the frequency of monitoring and the criteria used to assess animal health and well-being. Thank you for your attention to these requests. 4. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information. [Note: HTML markup is below. Please do not edit.] 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: Yes Reviewer #2: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes ****** 3. 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 ****** 4. 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 ****** 5. 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: Fortea and colleagues compared the performance of two anesthetic options in a pre-clinical model of non-cirrhotic portal hypertension, and in control animals. Authors demonstrate that ketamine+diazepam has several disadvantages including high mortality and modification of biochemical tests, which were not observed in the sevoflurane group. The topic of the study is relevant, especially considering the diverse anesthetic options and administration routes that are being used in the pre-clinical scenario. Thus, the study is interesting and, also, elegantly developed. The researchers have deep experience in the field of clinical and pre-clinical portal hypertension. I only have minor comments. - Methods. Number of animals per group is not homogeneous. Could authors comment on the possible mortality due to PPVL procedure or other reasons leading to such variance. - Results. Portal pressure measurement. Authors observe no differences in PP values when comparing both groups of PPVL animals. This could be predicted considering that in the PPVL model a major contributor to the increment in the porto-vascular resistance (and therefore in PP) is the physical knot that indeed modifies the pre-hepatic resistance. Splanchnic hemodynamic measurement would be interesting to further assess the effects of both anesthetics. Could authors comment here and in the manuscript? - Results. How authors interpret their findings on sevoflurane-associated mortality? Why was it higher in the ctrl vs the ppvl group? - Discussion. Although this is an interesting and timely study, these same analyses would be desirable in pre-clinical models of cirrhotic portal hypertension where hepatic function is compromised and, probably, hepatic metabolism of anesthetics would play a bigger role. This limitation/future opportunity should be discussed in the manuscript. Also, I would suggest to include “non-cirrhotic portal hypertension” in the title and abstract of the manuscript. Reviewer #2: The authors have contributed with a very nice piece of work on the method of anesthesia in experiments models of non-cirrhotic portal hypertension. the data are convincing and performed state of the art, yet I have some minor suggestions: 1. the title and through out the manuscript the authors should state that these are findings on non-cirrhotic portal hypertension. they cannot generalize those findings in cirrhotic models such as BDL and CCL4, this should be seen at first sight. 2. the data presented as text, should be presented in tables, e.g. BW, duration of the measurements, biochemistry and blood-gas-analysis. 3. in figure 1 A and B the two different groups of each sevoflurane and ketamine/diazepam should be plotted besides each other not together. ****** 6. 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. https://doi.org/10.1371/journal.pone.0233778.r001
Revision 1
7 May 2020 Author Response Reviewer #1: Methods 1. Number of animals per group is not homogeneous. Could authors comment on the possible mortality due to PPVL procedure or other reasons leading to such variance. No mortality due to the PPVL procedure was observed. The variability in the number of animals between groups was due to the increased mortality in the groups anesthetized with Ketamine-Diazepam (KD) for the hemodynamic study. In order to have similar group sizes with available hemodynamic data, we included more rats in both KD groups. Results 2. Portal pressure measurement. Authors observe no differences in PP values when comparing both groups of PPVL animals. This could be predicted considering that in the PPVL model a major contributor to the increment in the porto-vascular resistance (and therefore in PP) is the physical knot that indeed modifies the pre-hepatic resistance. Splanchnic hemodynamic measurement would be interesting to further assess the effects of both anesthetics. Could authors comment here and in the manuscript? We agree with Reviewer 1 that a major contributor to the increase in PP in the PPVL model is the increase in the pre-hepatic resistance caused by the physical knot. Although anesthesia cannot affect this “fixed resistance”, four days after the PPVL operation (time at which the hemodynamic study was performed) the hyperdynamic splanchnic and systemic circulation characteristic of portal hypertension are well established and contribute to the increase in PP (Sikuler et al, Am J Physiol. 1985;248: G618-625). The anesthetic regime may influence these other factors, and therefore affect PP values. Measurement of splanchnic flow as suggested by the reviewer would have provided valuable data concerning this issue. We have added a comment in the 2nd paragraph of Discussion (page 20): “Although no measurement of splanchnic flow was performed, the similar increase of portal pressure in PPVL rats suggests that both anesthetic regimes had a similar effect (or no effect) on the hyperdynamic splanchnic and systemic circulation induced by the PPVL, as pre-hepatic resistance was “fixed” by the PPVL operation.”. 3. How authors interpret their findings on sevoflurane-associated mortality? Why was it higher in the ctrl vs the PPVL group? No mortality was observed in control and PPVL groups anesthetized with sevoflurane. As far as the higher KD-associated mortality found in the Ctrl vs the PPVL group is concerned, we cannot provide a solid explanation. We can speculate that it may be partially related to the unpredictable individual sensitivity to ketamine, which is unlikely to be influenced by the hemodynamic changes induced by the PPVL procedure. To confirm this hypothesis, however, would likely require very large sample-size of both groups. Discussion 4. Although this is an interesting and timely study, these same analyses would be desirable in pre-clinical models of cirrhotic portal hypertension where hepatic function is compromised and, probably, hepatic metabolism of anesthetics would play a bigger role. This limitation/future opportunity should be discussed in the manuscript. Also, I would suggest to include “non-cirrhotic portal hypertension” in the title and abstract of the manuscript. We agree with both reviewers in this issue. This limitation has been included in the 4th paragraph of Discussion (page 21): “It is important to point out, however, that the PPVL model induces pre-hepatic portal hypertension, which limits the extrapolation of our findings to animal models of cirrhosis (e.g. carbon tetrachloride). Future studies would be needed to assess if the performance of the KD anesthetic regime is altered further by the potential pharmacokinetic and pharmacodynamic derangements induced by cirrhosis”. We have also included “non-cirrhotic portal hypertension” in the title, abstract and throughout the manuscript. Reviewer #2: 1. The title and throughout the manuscript the authors should state that these are findings on non-cirrhotic portal hypertension, they cannot generalize those findings in cirrhotic models such as BDL and CCL4, this should be seen at first sight. We agree with both reviewers in this issue. This limitation has been included in the 4th paragraph of Discussion (page 21): “It is important to point out, however, that the PPVL model induces pre-hepatic portal hypertension, which limits the extrapolation of our findings to animal models of cirrhosis (e.g. carbon tetrachloride). Future studies would be needed to assess if the performance of the KD anesthetic regime is altered further by the potential pharmacokinetic and pharmacodynamic derangements induced by cirrhosis”. We have also included “non-cirrhotic portal hypertension” in the title, abstract and throughout the manuscript. 2. The data presented as text, should be presented in tables, e.g. BW, duration of the measurements, biochemistry, and blood-gas-analysis. A new Table has been added with the data of BW, duration of the hemodynamic study and blood biochemistry. as suggested by the reviewer (Table 2, page 15). We preferred to leave arterial blood gas data in the text, as we presented compounded data of the Ctrl and PPVL groups of each anesthetic group. 3. In Figure 1A and B the two different groups of each sevoflurane and Ketamine/Diazepam should be plotted besides each other not together. Figure 1 has been modified according to these recommendations. Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0233778.r002
13 May 2020 Decision Letter - Matias A Avila, Editor Sevoflurane versus ketamine+diazepam anesthesia for assessing systemic and hepatic hemodynamics in rats with non-cirrhotic portal hypertension. PONE-D-20-08262R1 Dear Dr. Vaquero, 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. Within one week, you will receive an e-mail containing information on the amendments required prior to publication. When all required modifications have been addressed, you will receive a formal acceptance letter and your manuscript will proceed to our production department and be scheduled for publication. Shortly after the formal acceptance letter is sent, an invoice for payment will follow. To ensure an efficient production and billing process, please log into Editorial Manager at https://www.editorialmanager.com/pone/, click the "Update My Information" link at the top of the page, and update your user information. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, you must inform our press team as soon as possible and no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. With kind regards, Matias A Avila, Ph.D. Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0233778.r003
Formally Accepted
19 May 2020 Acceptance Letter - Matias A Avila, Editor PONE-D-20-08262R1 Sevoflurane versus ketamine+diazepam anesthesia for assessing systemic and hepatic hemodynamics in rats with non-cirrhotic portal hypertension. Dear Dr. Vaquero: I am pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please notify them about your upcoming paper at this point, to enable them to help maximize its impact. If they will be preparing press materials for this manuscript, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. For any other questions or concerns, please email plosone@plos.org. Thank you for submitting your work to PLOS ONE. With kind regards, PLOS ONE Editorial Office Staff on behalf of Dr Matias A Avila Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0233778.r004

Open letter on the publication of peer review reports

PLOS recognizes the benefits of transparency in the peer review process. Therefore, we enable the publication of all of the content of peer review and author responses alongside final, published articles. Reviewers remain anonymous, unless they choose to reveal their names.

We encourage other journals to join us in this initiative. We hope that our action inspires the community, including researchers, research funders, and research institutions, to recognize the benefits of published peer review reports for all parts of the research system.

Learn more at ASAPbio .