Immune Response to Extracellular Matrix Bioscaffolds: A Comprehensive Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript offers a comprehensive overview of immune interactions with ECM bio-scaffolds and provides sufficient background for readers. The authors mainly concentrate on the immune response after implantation during the inflammatory, proliferative, and remodeling phases. It also helps differentiate between pro-remodeling and pro-inflammatory outcomes and discusses how GMPs and QC influence ECM bioactivity. The review is well-structured and presented logically. The figures are clearly labeled and relevant to the sections. The discussion effectively integrates the findings and includes appropriate citations. However, some sections require further attention from the authors.

1. The review mentions DNA and chemical residual thresholds but does not specify quantitative benchmarks or standardized testing methods in detail.
2. There is limited discussion on how ECM degradation products influence antigen presentation, Treg induction, or B cell tolerance.
3. Macrophage phenotyping is addressed superficially. Including some techniques, such as multiparametric profiling, would be beneficial for readers.
4. The final sentence calls for processes that “eliminate cellular membrane material” but does not consider how to preserve GAGs at the same time.
5. A concise summary table would help readers quickly understand the dual roles of ECM carbohydrates and the processing trade-offs.
6. The section states that ECM bioscaffolds “clearly have a biologics nature” but does not clarify how current FDA or EMA frameworks classify them.
7. Additionally, the authors claim that manufacturers avoid biologics pathways because they are “expensive,” but do not provide concrete examples of delayed approvals or increased costs.
8. “While this does not represent a risk for patients given the extended use of ECM scaffolds in regenerative medicine, it could limit ECM bioscaffolds potential in clinics.” The phrase “does not represent a risk for patients” is contradictory and could be misinterpreted. I suggest rewriting as “Long-term outcomes confirm low safety concerns” or similar.
9. The manuscript mainly focuses on biological cues (GAGs, MBVs, peptides) and processing variables (residuals, decellularization), and adding a table of ECM material properties and their immunological implications would greatly strengthen the manuscript.
10. I have noticed that the lines are long. Break these into shorter lines.

Overall, this manuscript offers a valuable resource for students and researchers, providing a detailed overview of the complex immune responses to ECM bioscaffolds.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

Immune response to extracellular matrix bioscaffolds: A comprehensive review

Romero et al, have written a review based on the “Immune response on the extracellular matrix bioscaffolds…”. The authors have well described the effects of immune cells on the bioscaffolds used in patients and different levels of immune response due to the different biocompatibility. This review is very helpful in understanding the application of different materials used surgically. However, I have a few queries to be answered.

1. What are the effects of bioscaffolds in patients suffering from metabolic disorders like diabetes or cardiovascular diseases?
2. What kind of immune responses are generated in patients with different blood groups and RH factors having bioscaffold implantation?
3. What kind of immune response are generated in patients of different ages and genders?
4. It could be advantageous if authors could incorporate different organs that fail after scaffold implantation, and response to immunosuppression.

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The review by Romero et al. is a well written, comprehensive and up to date. The authors focus the review on scaffolds used for regenerative medicine. They start by discussing synthetic scaffolds and the expected and observed immune response. This section is important because it sets the stage for a comparison to biological scaffolds. The next sections are a detailed description of biological scaffolds with an emphasis on ECM derived scaffolds. 

The authors make a clear differentiation between immune reactions against the acellular ECM versus cellular debris that may be present due to incomplete processes of the scaffolds. This is important. Many previous reviews do not make this distinction and this explains why some studies argue the ECM is highly immunogenic and others observe the opposite result.

Specifically, they draw attention to residual DNA and alpha-gal, two areas important to acellular ECM scaffolds but not always properly discussed.

Continuing along this line of thinking, this review includes information on the different preparation methods for bio-scaffolds and where purity/immunogenic issue may present themselves. This adds to the 'complete' story they are presenting with this review.

One point that is missing is some information about the high conservation of organ ECM between species. Although heart ECM is very different from kidney ECM, kidney ECM from mouse, pig and human are highly conserved. This is why antibodies to ECM are not species specific and why acellular ECM is not rejected.

Author Response

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Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have satisfactorily addressed all the comments and modifying the manuscript. I recommend the Review for acceptance in this journal. I congratulate the authors for their wonderful work.