The Role of Amino Acid Glycine on Cardiovascular Health and Its Beneficial Effects: A Narrative Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Title: - The role of amino acid glycine on cardiovascular health and its beneficial effects: a review.

The review seems to be interesting yet some of the issues needs to be rectified before getting accepted.

1.      Most of the cited references are seems to be decade old and need to be modified with the current references.

2.      Abstract needs extensive revision by addressing the novelty of the review in the context to the previously published articles related to the theme of research.

3.      Figure. 1. It is better to display a 2D structure instead of 3D and also present a separate graphical image highlighting the molecular insights of glycine in treating different medical conditions.

4.      Introduction and conclusion part seems to be lucid needs to be rewritten by addressing the key challenges and limitations of the review respectively.

5.      The grammar seems to be a problem its better to revise it completely with an English editing service.

 Comments on the Quality of English Language

English editing required. 

Author Response

Reviewer 1

Title: - The role of amino acid glycine on cardiovascular health and its beneficial effects: a review. The review seems to be interesting yet some of the issues need to be rectified before getting accepted.

1. Most of the cited references seem to be decades old and need to be modified with the current references.

As suggested, we added new recent references, when possible, both in the introduction and throughout the article (References # 5 and 11). Some of the cited references in the first version had relevant findings and were therefore included in the paper, even though they were not so recent.

2. The abstract needs extensive revision by addressing the novelty of the review in the context of the previously published articles related to the theme of research.

As suggested, the abstract was modified to highlight its relevance and mention the focus on the mechanisms of action (lines 22-28).

3. 1. It is better to display a 2D structure instead of 3D and present a separate graphical image highlighting the molecular insights of glycine in treating different medical conditions.

Thanks for your suggestions. Figure 1 was modified and presented in a 2D format.

4. The introduction and conclusion parts seem to be lucid and need to be rewritten by addressing the key challenges and limitations of the review respectively.

The introduction was rewritten, new references were added, and the importance of glycine in many metabolic processes was highlighted (lines 65-68). The conclusion was extended, and a summary of glycine's main mechanisms of action was added (See Table 1). Also, a section with the study's limitations was added, and more studies were needed to elucidate the mechanisms of action.

5. The grammar seems to be a problem, it’s better to revise it entirely with an English editing service.

As suggested, the grammar and wording were reviewed for correctness and clarity.

Reviewer 2 Report

Comments and Suggestions for Authors

This review did not address some novel information with the existing literature. Moreover, the manuscript was highly similar sentences with previous publication and requires major attention on the work. In this regard, I am not positive to recommend the manuscript for publication. 

Comments on the Quality of English Language

The manuscript requires extensive English editing. 

Author Response

Reviewer #2: General Comments:

1. This review did not address some novel information with the existing literature. Moreover, the manuscript was highly similar sentences with previous publication and requires major attention on the work. In this regard, I am not positive to recommend the manuscript for publication. 

Thanks for your comments. We carried out an extensive search, and no other review focused on the benefits of glycine on cardiovascular diseases was found, which is why we considered it necessary to write this review.

Reviewer 3 Report

Comments and Suggestions for Authors

This is a well-reasoned and well-crafted review of what is currently known about the role of amino acid glycine on cardiovascular health and its beneficial effects. The authors have developed a basic good title, but it does not include the methodology used. Is it a systematic or narrative review? I think it is necessary to specify. The abstract could be improved, it doesn't consider a methodology of data collection, study, or discussion. I think it should include the mandatory subjects as per the mandatory sections as per the journal’s guidelines for narrative reviews (Background, Methods, Results, Conclusion). The text is lacking in the materials and methods section, the authors have omitted how they carried out the literature search, and which articles they chose. I would advise the authors to add more references to the introduction to provide a better background of the study.  I think there should be a table describing the most relevant results of the beneficial effects of glycine on cardiovascular diseases. From my point of view, the conclusions were vague. I would advise the authors to expand the conclusions. The manuscript I think should undergo a moderate review of the English language to address errors in grammar and overall fluency.

Comments on the Quality of English Language

The manuscript I think should undergo a moderate review of the English language to address errors in grammar and overall fluency.

Author Response

Reviewer #3: General Comments:

1. This is a well-reasoned and well-crafted review of what is currently known about the role of amino acid glycine on cardiovascular health and its beneficial effects. The authors have developed a basic good title, but it does not include the methodology used. Is it a systematic or narrative review? I think it is necessary to specify.

Thanks for your suggestions. As suggested, the title was modified, and we specified in the title that it is a narrative review. A section with the methodology of the research was also added.

2. The abstract could be improved, it doesn't consider a methodology of data collection, study, or discussion. I think it should include the mandatory subjects as per the mandatory sections as per the journal’s guidelines for narrative reviews (Background, Methods, Results, Conclusion). The text is lacking in the materials and methods section, the authors have omitted how they carried out the literature search, and which articles they chose.

The abstract was modified, establishing that the paper will show glycine's primary mechanisms of action. On the other hand, in this case, as a review article, we considered it was not suitable to add a separate results and discussion section, as same as a research article. Thus, the results of the bibliographic review were presented and organized in different sections, classified by health diseases, and the importance and role of glycine in the different illnesses were discussed in each section, to make the reading process easier. Also, a methodology section was added.

3. I would advise the authors to add more references to the introduction to provide a better background of the study.

Thanks for your suggestions. New information was added to the introduction to highlight the importance of glycine in metabolic processes (Reference #5).

4. I think there should be a table describing the most relevant results of the beneficial effects of glycine on cardiovascular diseases.

As suggested, a table (Table 1) was added with the most relevant results of glycine's beneficial effects and mechanisms of action.

5. From my point of view, the conclusions were vague. I would advise the authors to expand the conclusions.

Thanks for your suggestions. The conclusion section was rewritten, including the most relevant mechanisms of action for glycine were added.

6. The manuscript I think should undergo a moderate review of the English language to address errors in grammar and overall fluency.

As suggested, the grammar and wording were reviewed for correctness and clarity.

Reviewer 4 Report

Comments and Suggestions for Authors

The role of amino acid glycine on cardiovascular health and its beneficial effects: the review is an article with an interesting research topic, however there are critical points that should be revised for a future submission:
- The abstract lacks quality; the objectives, main outcomes and conclusions should be described;
- The research gap and the rationale of the study are superficially presented in the study. It should also frame the objectives of the study;
- the expositions presented in the review should be expanded and focused on a single topic of analysis. The authors refer to the potential benefits of amino acid glycine on cardiovascular health, but should better specify the physiological processes behind these benefits. In addition, the physiopathological processes of cardiovascular diseases presented in figure 2 should be improved.

I recommend thorough changes to the narrative review before re-submission.

Author Response

Reviewer #4: General Comments:

1. The role of amino acid glycine on cardiovascular health and its beneficial effects: the review is an article with an interesting research topic, however, there are critical points that should be revised for a future submission. The abstract lacks quality; the objectives, main outcomes, and conclusions should be described.

Thanks for your recommendations. The abstract was modified to improve its quality and address the missing information ( objective, main outcomes, etc).

2. The research gap and the rationale of the study are superficially presented in the study. It should also frame the objectives of the study;

The review summarizes the beneficial effects of glycine and its mechanisms of action. Thus, to clarify the objective, the abstract and introduction were rewritten. Also, a table of the mechanism of action of glycine was added (Table 1).

3. The expositions presented in the review should be expanded and focused on a single topic of analysis. The authors refer to the potential benefits of amino acid glycine on cardiovascular health but should better specify the physiological processes behind these benefits. In addition, the physiopathological processes of cardiovascular diseases presented in Figure 2 should be improved.

Thank you for your suggestions. To address this issue, we added Table 1, which contains the mechanisms of action of glycine.

4. I recommend thorough changes to the narrative review before re-submission.

Thank you for your suggestions. The manuscript was modified, and sections were rewritten in the abstract, introduction, and conclusions to improve the study's quality. Also, grammar and spelling were checked.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript is acceptable in its current form

Reviewer 2 Report

Comments and Suggestions for Authors

No further comments 

Comments on the Quality of English Language

None

Reviewer 4 Report

Comments and Suggestions for Authors

Dear Authors,

After extensive peer review, I recommend accepting the manuscript in its present form.

Congratulations!