Lacto-Fermented and Unfermented Soybean Differently Modulate Serum Lipids, Blood Pressure and Gut Microbiota during Hypertension

Round 1

Reviewer 1 Report

In the manuscript, Daliri et al. investigated the effects of soybean fermentation on serum lipids, blood pressure and gut microbiota during hypertension. It’s an interesting work, which would facilitate relative subjects. Several concerns I would like to rise, are as follows,

1.     Please revise the entire context carefully to get rid of some format mistakes, such as Line 27 (Keywords appeared twice), Line 139, Line 157 and so on.

2.     In Line 207, the authors should indicate the name of the package they applied in R software.

3.     The significantly different display is confused in the figures. The authors used asterisk, letters and p value to show significantly different among groups. I suggest to stick on one way for the context.  

4.     In Figure 2 (A), what is the meaning of from 2 to 10? Fold change or relative concentrations? Such information should be clarified.

5.     The authors applied PCA for the gut microbiota data. While totally no separations appeared both along PC 1 and PC 2. It is better to think twice which information the authors would indicate through this plot, and if possible, to find other more suitable approaches?

6.     The authors should extend the discussion section so as to make readers have a deep understanding of the mechanisms and relationships among the factors tested.   

Author Response

RESPONSE TO REVIEWER COMMENTS

 

Q1.     Please revise the entire context carefully to get rid of some format mistakes, such as Line 27 (Keywords appeared twice), Line 139, Line 157 and so on.

Response: The manuscript has been revised as suggested and format mistakes have been corrected.

 

Q2.     In Line 207, the authors should indicate the name of the package they applied in R software.

Response: L207-208: It has been indicated that R software version 4.1.3 was used.

 

Q3.     The significantly different display is confused in the figures. The authors used asterisk, letters and p value to show significantly different among groups. I suggest to stick on one way for the context.  

Response: We have indicated that bars with * and data points with different alphabets were significantly different (p < 0.05) according to paired t-tests (L240-241). Sticking to just one way to indicate the significant value will make some of the graphs difficult for readers to interpret.

 

Q4.     In Figure 2 (A), what is the meaning of from 2 to 10? Fold change or relative concentrations? Such information should be clarified.

Response: We have indicated in L207 that the values of 2 to 10 indicate the relative concentrations of the compounds.

 

Q5.     The authors applied PCA for the gut microbiota data. While totally no separations appeared both along PC 1 and PC 2. It is better to think twice which information the authors would indicate through this plot, and if possible, to find other more suitable approaches?

Response: Our aim was to find out if consumption of USB and FSB have impact on the gut microbiome and we found that they cause significant changes. Therefore in L297, we indicated that principal component analysis revealed that both FSB and USB consumptions had distinct impacts on SHR gut microbiota.

 

Q6.     The authors should extend the discussion section so as to make readers have a deep understanding of the mechanisms and relationships among the factors tested.

Response: We have extended the discussion by including in L397-40, that previous studies have indicated that, overactivation of ACE can stimulate LDL-C accumulation which will eventually increase vascular superoxide production and result in hypertension [38]. For this reason, it is likely that FSB reduced high blood pressure by inhibiting ACE activity leading to a reduction in reactive oxygen species and LDL-C levels.

Reviewer 2 Report

The authors investigated that fermented and unfermented soybean differently adjusted dysregulated serum lipids and gut microbiota, high blood pressure. Although it is a descriptive research, it is clearly demonstrated that fermented soybean consumption produced more beneficial effects because it contained more phenolic compounds, ACE inhibitory peptides and probiotics. Oral peptide supplements may not enter the bloodstream as the body may break them down into individual amino acids. The authors should discuss the possible mechanism of ACE inhibitory peptides antihypertensive effects after oral supply of fermented and unfermented soybean. It will be perfect if the authors measure the abundance of ACE inhibitory peptides in the serum samples.

Author Response

Response to reviewer

Orally administered peptides may escape digestion and enter into the blood stream depending on their sizes as we reported elsewhere (https://doi.org/10.1016/j.lwt.2018.03.026). Also, we showed in an earlier study that, although gastrointestinal digestion may inactivate some peptides, the process may also generate shorter peptide sequences that may be absorbed into circulation (https://doi.org/10.3390/ijms20061496) (L397-400). 

Furthermore, since we did not administer isolated peptides but rather the whole  sample (FSB and USB), we think that the ability of FSB to inhibit ACE activity in vitro and in vivo is enough to evidence to show that certain components of FSB must have entered into circulation to reduce ACE activity in the serum and to reduce the blood pressure. 

Additionally, as we did not administer pure peptides to the SHR, we do not think it is necessary to measure the levels of peptides in the rat serum as they will too many. 

Round 2

Reviewer 1 Report

Question 2, the authors should indicate which R package did they apply.

Question 3, unfortunately, I do not agree with the response. For example, in Figure 1A, the authors showed significant differences between Group 1 and 2, Group 2 and 3. While what about Group 1 and 3? Stick on letters should be more suitable.

Question 5, according to the response, the authors would like to show both FSB and USB consumptions had distinct impacts on SHR gut microbiota. While totally no separations appeared in PCA plot.

Author Response

Question 2, the authors should indicate which R package did they apply.

Response: We have indicated that R software version 4.1.3 (ggpubr package) was used (L207).

Question 3, unfortunately, I do not agree with the response. For example, in Figure 1A, the authors showed significant differences between Group 1 and 2, Group 2 and 3. While what about Group 1 and 3? Stick on letters should be more suitable.

Response: We have used alphabets to indicate the significant difference between the groups as recommended by the reviewer (Fig 1A).

Question 5, according to the response, the authors would like to show both FSB and USB consumptions had distinct impacts on SHR gut microbiota. While totally no separations appeared in PCA plot.

Response: What we intend to show is that consumption of USB or FSB changes the gut microbiota of SHR. From the plot, SHR experimental animals are represented by the red dots. After feeding with USB or FSB, the light green dots or deep blue dots are seen (which are separated from the red dots). This indicates that FSB and USB have significant impact on SHR gut microbial diversity.