Review Reports

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper "Redefining the Collagen Composition of Human Fasciae: Emerging Collagen Types and Structural Heterogeneity" further elaborates the understudied subject of collagen type composition of superficial and deep human fascia, which is important for the understanding of fascial structure, functions, and treatment. The review in Introduction is informative, the Methods are completely described, and the Results are clearly presented. Discussion emphasizes what is actually found to be new and connects it with what is known, Conclusion is legitimate, and the References are up to date.

There are yet some minor issues to address:

1. Cannot see a reason to begin “collagen” with capital, usual small letter way will do. Also examine spacings, chemical subscripts, other irrelevant capitals like collagen fibers (Blue) cet.
2. Apart from the exclusion criteria mentioned, the patients could be initially susceptible to hip joint destruction and spinal trauma, so how do you consider that their collagen composition could differ from typical/normal?
3. Figures 3-6. The number of dots for each group is the number of what? How does it correspond with 19 patients, 8 lower back samples, and 11 thigh samples? I guess, some values were excluded - why? Standard deviation (mentioned it the Methods section) is not shown graphically. Also, i suggest you to draw bars for better visualization. I also think that frames can be omitted, especially the artifact thin lines between axes and inner titles in Fig. 3. Also, why the different shapes? All rounds will do, especially with bars.
4. 3 replicates for each experiment – did you average them, or did something else?
5. The total collagen content analysis revealed a significantly (**p=0.006) higher amount – the ** is excessive, since you indicate the value.
6. mean quantity of Collagen type I (0.11 ± 0.08, p=**) – better to indicate the value instead of such notation. The same for the further text.
7. This variability persisted when the data were stratified by sex or age, with no significant differences observed between these subgroups (data not shown)… However, the small sample size limits further sub-categorization by factors such as sex, age, or other variables, which showed no significant differences between subgroups - It would help if there were indicated the age, gender and sample type for each subject, like “1 – male, 40 y. o., lower back” cet. Currently, even the average age of the patients is not clear. So far, the reader can only guess what age subgroups there could even be.
8. Figure 8. Instead of awkward frame structure, I suggest a tree-like graph (see attached prototype, it can be rotated or flipped cet.)
9. Examine the wording for “low back”. It is in the right place in “low(er) back pain”, but with fascia consider “lumbar”.

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have completed a study of collagen composition and distribution in the superficial and deep fasciae of the human thigh and low back. The study demonstrates the presence of collagen types VI and XII in fasciae, and regional distribution of collagen types I, III, VI and XII. The authors relate collagen type distribution to function of fasciae.

The Methods section is written clearly, facilitating study reproduction by other investigators. The Results section, however, appears to present selected data, which requires further description.

Figure 1 shows H&E staining and Figure 2 shows Azam Mallory staining of superficial and deep fascia. There is no description of the regional source of these samples. Moreover, as structural comparisons are to be made between superficial and deep fascia, it would be helpful to have images of the same magnification (Figure 1 scale bars indicate difference in magnification).

Importantly, Figures 3, 4, 5, and 6 appear to include a subset of samples from the 19 described in the Methods section. The authors are encouraged to explain which data are presented and/or the rationale for exclusion of some samples from analyses. For example, Figure 3 presents quantitative hydroxyproline data from 14 superficial fasciae and 15 deep fasciae, subsets of the 19 donor tissues described in the Methods section. Figure 4A presents data from 14, 17, 17, and 18 samples from superficial fasciae and Figure 4B presents 9, 12, 9, and 7 samples from deep fasciae. Figure 4 describes Western blot analyses of superficial fasciae from donations from 8 low backs and 11 thighs per the Methods section. However, data are presented for 4 to 7 low back samples and 10 to 11 thigh samples. Similarly, Figure 6 presents Western blot analyses of deep fascia based on 3 to 8 samples. Original images of Western blots are provided but are not labeled, making them difficult to interpret.

There are a few segments wherein the text could be revised for clarity.

The textual descriptions of ratio values and zone-dependent differences in collagen types are difficult to follow. This reviewer made a table in order to follow the text, A table of these data would be informative.

In the Discussion section, the authors are encouraged to remove the reiterated results from the Discussion (paragraphs 2, 3, 6, and 8), as these cause the reader to lose the main concept or argument.

Figure 8 is confusing to this reviewer and does not add substantially to the manuscript. If the figure is to be included, the authors are encouraged to provide a reference that describes variations in collagen type structures.

Given the novelty of findings of collagen VI and XII in fasciae, the authors may wish to include this recent reference:  Gregory et al., The coordinated activities of collagen VI and XII in maintenance of tissue structure, function and repair: evidence for a physical interaction. Front. Mol. Biosci. 2024.

Comments on the Quality of English Language

There are a few areas wherein the English may be improved, and these may be identified in final proof.  The primary areas for improvement are detailed in the review (Results section textual descriptions of ratio values and zone-dependent differences in collagen types; Discussion section removal of reiterated results).

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have adequately addressed the concerns of this reviewer, and the paper is improved.

One minor point for Table 1.  Would it be more accurate to use "Sex" rather than "Gender" in describing the study participants?  Sex is a biological categorization, while gender is a cultural choice.