Current Topics of the Mechanism of Intestinal Fibrosis in Crohn’s Disease

Round 1

Reviewer 1 Report

In the manuscript “Current topics of the mechanism of intestinal fibrosis in Crohn's disease”, A good attempt is made by writing introduction and discussion with relevant background. However following points need to be addressed.

1. In previously published article “Rieder F., Fiocchi C. Intestinal fibrosis in inflammatory bowel disease—Current knowledge and future perspectives. J. Crohns Colitis. 2008;2:279–290. doi: 10.1016/j.crohns.2008.05.009.” authors have covered most part of this review in terms of inflammatory bowel disease.                             Authors have not been discussed/referred above article. Please justify same.
2. Current treatment strategies for intestinal fibrosis in CD is not mentioned. Hence proper discussion of current and future therapies will enhance reader interest.

Author Response

Dear Editorial Board

Thank you very much for reviewing our manuscript entitled “Current topics of the mechanism of intestinal fibrosis in Crohn's disease” together with the comments from Editorial Board.

 

We appreciate the kind comments from reviewers as well as their suggestion. We have changed the manuscript to address the concerns of reviewers. All changes are indicated in the text by visible track changes. We believe that these changes will render the manuscript acceptable for publication.

 

The major modification as a result of point-by-point replies to the issues raised by Editorial Board were itemized as follow:

 

 

 

 

 

 

 

Responses to comments of Reviewer 1

In the manuscript “Current topics of the mechanism of intestinal fibrosis in Crohn's disease”, A good attempt is made by writing introduction and discussion with relevant background. However following points need to be addressed.

 

(1) In previously published article “Rieder F., Fiocchi C. Intestinal fibrosis in inflammatory bowel disease—Current knowledge and future perspectives. J. Crohns Colitis. 2008;2:279–290. doi: 10.1016/j.crohns.2008.05.009.” authors have covered most part of this review in terms of inflammatory bowel disease.  Authors have not been discussed/referred above article. Please justify same.

 

Thank you very much for the reviewer 1’s comment. According to the reviewer’s 1 suggestion, the reference you have provided are important to this paper, and we have cited it and added the following sentence.

In detail, we added the sentence as follows;

“The clinical issue of CD intestinal stricture related to CD still unclear, but the pathophysiology has been elucidated based on the progress of recent research [9, 13, 18, 19].” in Line 27 to Line 28 of Page 2.

(2) Current treatment strategies for intestinal fibrosis in CD is not mentioned. Hence proper discussion of current and future therapies will enhance reader interest.

 

Thank you very much for the reviewer 1’s comment. As the reviewer 1

mentioned, there is a need to describe current treatment strategies for Crohn's

disease, so we have created a new section and added the sentences as follow;

“3. Current treatment strategies for intestinal stricture of patients with CD

　　     Management of CD intestinal stricture includes drug therapy, endoscopic treatment (e.g. endoscopic balloon dilation) and surgical treatment (e.g. strictureplasty). Drug therapy may be successful in inflammation-driven strictures, but is less effective in fibrotic stenoses and endoscopic or surgical treatment should be considered [4, 5, 15]. The indications for various treatments for intestinal stricture of CD depends on the individual patient's clinical condition. Recent advances in medical treatment have resulted in higher efficiency and improvement in the treatment of CD patients, and the indication and need for surgery in CD patients will probably be lower in the treatment of inflammation-based stricture. However, deciding whether a patient needs surgery or continues medical treatment is currently a difficult question and often requires a comprehensive assessment [4, 16]. Therefore, the strong relationship between preoperative bowel wall thickening and postoperative recurrence suggests the significance of anti-inflammatory treatment, for avoiding intestinal stricture [17].” in Line 11 to Line 24 of Page 2.

Author Response File: Author Response.docx

Reviewer 2 Report

In this manuscript the authors present a review of pathophysiology of intestinal fibrosis particularly intestinal stricture formation involving immune and non-immune cells. Improved understanding of the mechanisms will favor the ongoing development of clinical trials. However, the data presented does not reflect the title of the manuscript (Mechanism of intestinal fibrosis on Crohn’s disease) as the mechanisms of action are described in a very superficial manner. Moreover, a more concise and focused information of the most important mechanisms ex: PAMPs from different microorganisms needs to be addressed. The commensal microbial stimulants can be covered under a  different heading.

I acknowledge that this is an evolving research field but there is already significant data regarding the interaction between chronic intestinal inflammation and the enteric bacteria. Therefore, some of the newest findings in this area should be mentioned in a potential revised form of the manuscript.

 

Minor comments:

1. Among these diseases, IBD, which includes Crohn's disease (CD) and ulcerative colitis (UC), is an intractable disease requiring lifelong treatment due to inflammation caused by immunologic abnormalities specific to the intestinal tract [2, 3]. At present, no radical treatment exists for either disease,

            What does authors think about Strictureplasty ? serial ultrasound examinations after strictureplasty, reduces thickness and inflammation of the intestinal wall (Maconi G, et al. Preoperative characteristics and postoperative behavior of bowel wall on risk of recurrence after conservative surgery in Crohn's disease: a prospective study. Ann Surg. 2001;233(3):345–52).

Consider rewriting the sentence and avoid no treatment.

 

2. In this review [9, 10], we describe the pathogenesis of intestinal fibrosis in CD and potential future treatments.

            What is the point of this reference?

 

3. CD is a chronic inflammatory bowel disease associated with immunologic abnormalities. The disease affects mainly young people, and intestinal inflammation (e.g., gastrointestinal ulcers, mainly in the small and large intestines) and intestinal complications (e.g., intestinal stricture, fistula, and anal lesions) are often observed

            Sentence doesn’t read properly.

 

4. various cytokines and growth factors are strongly involved in the differentiation and proliferation of these cells (chemokines are strongly involved in the migration of bone marrow-derived mesenchymal stem cells to tissues), and promote the excessive production and accumulation of the ECM

                  Since the authors mention only 2 of the mechanisms involved, it will be very informative if they explain both in detail. For example: the paracrine signals from immune and non-immune cells are mentioned but it is also worth mentioning the autocrine factors (ex:TLRs)

 

5. In the innate immune system, immune cells are activated mainly by the production of tumor necrosis factor (TNF)-α,transforming growth factor (TGF)-β1, plate-let-derived growth factor, and others

                Tnf-alpha and IL-12p40 are the main drivers of pathogenesis.

6. Reduce the number of references, and mention only recent reviews.
7. Clarification of the involvement of specific bacteria in intestinal bacteria is also expected to lead to the control of intestinal fibrosis

                  What does authors mean by “specific bacteria in intestinal bacteria” Consider rewriting this sentence.

Author Response

Dear Editorial Board

Thank you very much for reviewing our manuscript entitled “Current topics of the mechanism of intestinal fibrosis in Crohn's disease” together with the comments from Editorial Board.

 

We appreciate the kind comments from reviewers as well as their suggestion. We have changed the manuscript to address the concerns of reviewers. All changes are indicated in the text by visible track changes. We believe that these changes will render the manuscript acceptable for publication.

 

The major modification as a result of point-by-point replies to the issues raised by Editorial Board were itemized as follow:

 

 

 

 

 

 

 

Responses to comments of Reviewer 2

(Major comment)

In this manuscript the authors present a review of pathophysiology of intestinal fibrosis particularly intestinal stricture formation involving immune and non-immune cells. Improved understanding of the mechanisms will favor the ongoing development of clinical trials. However, the data presented does not reflect the title of the manuscript (Mechanism of intestinal fibrosis on Crohn’s disease) as the mechanisms of action are described in a very superficial manner. Moreover, a more concise and focused information of the most important mechanisms ex: PAMPs from different microorganisms needs to be addressed. The commensal microbial stimulants can be covered under a different heading.

I acknowledge that this is an evolving research field but there is already significant data regarding the interaction between chronic intestinal inflammation and the enteric bacteria. Therefore, some of the newest findings in this area should be mentioned in a potential revised form of the manuscript.

　　

Thank you very much for the reviewer 2’s comment. As the reviewer 2 pointed  out, the description, including the mechanism of action, was very superficial and therefore inadequate. In particular, there was insufficient discussion of the interaction between chronic enteritis and enteric bacteria, which seems necessary in this paper. In order to respond to the reviewer 2's comments, we have added a new section (Microbiota and intestinal fibrosis) on the most important points raised by the reviewer 2, citing PAMPs, and a separate section on recent reports on intestinal bacteria and CD, focusing on fibrosis. For this reason, the section on immune cells in 5-(2), which mentions intestinal bacteria, has been incorporated into this section.

    “6. Microbiota and intestinal fibrosis

In addition to the paracrine signals from immune and non-immune cells described above, myofibroblasts are activated by a variety of mechanisms, including autocrine factors secreted by myofibroblasts and pathogen-associated molecular patterns (PAMPs) of microbial origin that interact with pattern recognition receptors such as toll-like receptors (TLRs) [18, 40]. Toll-like receptors, consisting of TLR1 to TLR9, serve as sensors of the gut microbiota and are important in maintaining intestinal homeostasis, regulating immune responses and the formation of bacterial flora [41]. In particular, TLR4 signaling promotes pro-fibrotic activation of intestinal fibroblasts, enhances NF-κB promoter activity  and increases collagen contraction [30, 40].

Recent animal studies have demonstrated that these immune system cells response to specific bacteria and bacterial cell components (peptide glycans) in the intestinal tract can result in the secretion of cytokines and growth factors such as TGF-β1 and CTGF, and the activation of myofibroblasts. It is also reported that the sustained activation of ECM-producing cells worsen intestinal fibrosis [18, 29, 40]. Bacteria such as Mucispirillum schaedleri and Ruminococcus in the cecum and Streptococcus and Lactobacillus in the ileum were positively correlated with fibrosis in the tumor necrosis factor-like cytokine 1A (TL1A) transgenic mouse model [42]. TL1A is a member of the tumor necrosis factor superfamily, which when overexpressed in mice causes spontaneous intestinal inflammation and fibrosis [43].

In particular, adherent-invasive Escherichia coli (AIEC), a mucosa-associated bacterium of E. coli, adheres to the gut epithelium and causes chronic intestinal inflammation in genetically susceptible hosts [28, 44]. AIEC strains are found more frequently than other strains in ileal specimens from patients with CD and are suspected to be involved in the initiation or progression of inflammatory processes in the gut [45]. In mice, chronic AIEC infection leads to tissue pathology in the small and large bowel, especially the cecum, with elevated Th1 and Th17 responses. In addition, compared to controls, the histology of the cecum of AIEC-infected mice showed extensive ECM deposition and the increased expression of collagen type I/III and profibrotic mediators such as TGF-β1, CTGF, and IGF-I. Similar findings were observed in intestinal stricture related to CD [46]. Clinical studies in humans revealed that dysbiosis is involved in the onset and exacerbation of CD [47, 48]. In addition, Clostridium innocuum has been found to migrate from the intestinal lumen of surgically resected CD samples into the mesenteric adipose tissue (MAT), drawing attention to its involvement in intestinal fibrosis. In this study, DSS-treated ASF-colonised mice (colonized with eight indigenous bacteria) were irrigated with C.innocuum, and the bacteria were detected by MAT. In addition, the activated macrophages in this mouse strongly produce various cytokines and growth factors, which leads to the induction of mesenteric adipocytes and intestinal fibrosis [49]. Studies using human samples of other bacteria have shown that patients with Crohn's disease have a reduced diversity of bacterial species representing the phyla Firmicutes and Bacteroidetes [50, 51]. These studies suggest that stimulation by specific intestinal bacteria and immune reactions is important for the onset and exacerbation of fibrosis.” in Line 1 of Page 5 to Line 2 of Page 6.

 

(Minor Comments)

• Among these diseases, IBD, which includes Crohn's disease (CD) and ulcerative

colitis (UC), is an intractable disease requiring lifelong treatment due to inflammation caused by immunologic abnormalities specific to the intestinal tract [2, 3]. At present, no radical treatment exists for either disease,

What does authors think about Strictureplasty ? serial ultrasound examinations after strictureplasty, reduces thickness and inflammation of the intestinal wall (Maconi G, et al. Preoperative characteristics and postoperative behavior of bowel wall on risk of recurrence after conservative surgery in Crohn's disease: a prospective study. Ann Surg. 2001;233(3):345–52)

 

Thank you very much for reviewer 2’s comment. The clinical aspects of intestinal fibrosis in Crohn's disease also need to be mentioned in this paper and a new section (Current treatment strategies for intestinal stricture of patients with CD) has been created. In addition, it describes the importance of the reviewer 2's question, taking into account the content of the paper mentioned by the reviewer 2.

   “3. Current treatment strategies for intestinal stricture of patients with CD

　　      Management of CD intestinal stricture includes drug therapy, endoscopic treatment (e.g. endoscopic balloon dilation) and surgical treatment (e.g. strictureplasty). Drug therapy may be successful in inflammation-driven strictures, but is less effective in fibrotic stenoses and endoscopic or surgical treatment should be considered [4, 5, 15]. The indications for various treatments for intestinal stricture of CD depends on the individual patient's situation. Recent advances in medical treatment have resulted in higher efficiency and improvement in the treatment of CD patients, and the indication and need for surgery in CD patients will probably be lower in the treatment of inflammation-based stricture. However, deciding whether a patient needs surgery or continues treatment is currently a difficult question and often requires a comprehensive assessment [4, 16]. Therefore, the strong relationship between preoperative bowel wall thickening and postoperative recurrence suggests that inflammatory treatment, including drug therapy, is also effective in the treatment of stricture and that multidisciplinary treatment is required [17].” in Line 11 to Line 24 of Page 2.

• In this review [7, 8], we describe the pathogenesis of intestinal fibrosis in CD and potential future treatments.

What is the point of this reference?

 

Thank you very much for reviewer 2’s comment. I am very sorry that the part 　to add the reference is different. We changed the position of the reference to the preceding sentence.

  “Despite recent progress in drug development for treating intestinal fibrosis,

there is currently no effective medical treatment [7, 8]. In this review [7, 8],

we describe the pathogenesis of intestinal fibrosis in CD and potential future

treatments.” In Line 15 of Page 1.

• CD is a chronic inflammatory bowel disease associated with immunologic

abnormalities. The disease affects mainly young people, and intestinal inflammation (e.g., gastrointestinal ulcers, mainly in the small and large intestines) and intestinal complications (e.g., intestinal stricture, fistula, and anal lesions) are often observed

Sentence doesn’t read properly.

 

       Thank you very much for reviewer 2’s comment. I'm very sorry that some of the sentences were not appropriate. We interpreted the review sentences as having a lot of unnecessary parts and corrected them as bellow.

In detail, we exchange the sentences “CD is a chronic inflammatory bowel disease associated with immunologic abnormalities. The disease affects mainly young people, and intestinal inflammation (e.g., gastrointestinal ulcers, mainly in the small and large intestines) and intestinal complications (e.g., intestinal stricture, fistula, and anal lesions) are often observed [6, 9, 10].” to “CD is a chronic inflammatory bowel disorder with remittent and relapsing episodes. Half of the adult CD patients will have intestinal complications, such as strictures or fistulas, within 20 years following their initial diagnosis [6, 9, 10].” in Line 18 to Line 20 of Page 1.

• various cytokines and growth factors are strongly involved in the differentiation and

proliferation of these cells (chemokines are strongly involved in the migration of bone marrow-derived mesenchymal stem cells to tissues), and promote the excessive production and accumulation of the ECM

Since the authors mention only 2 of the mechanisms involved, it will be very informative if they explain both in detail. For example: the paracrine signals from immune and non-immune cells are mentioned but it is also worth mentioning the autocrine factors (ex:TLRs)

       Thank you very much for reviewer 2’s comment. As the reviewer 2 mentioned, in addition to paracrine signals from immune and non-immune cells, we also mentioned autocrine factors, especially at the beginning of the newly added "Microbiota and intestinal fibrosis" section on TLRs, summarizing their importance.

      “In addition to the paracrine signals from immune and non-immune cells described above, myofibroblasts are activated by a variety of mechanisms, including autocrine factors secreted by myofibroblasts and pathogen-associated molecular patterns (PAMPs) of microbial origin that interact with pattern recognition receptors such as toll-like receptors (TLRs) [18, 40]. Toll-like receptors, consisting of TLR1 to TLR9, serve as sensors of the gut microbiota and are important in maintaining intestinal homeostasis, regulating immune responses and the formation of bacterial flora [41]. In particular, TLR4 is mainly derived from Gram-negative bacteria and the lipopolysaccharide recognised by this receptor promotes pro-fibrotic activation of intestinal fibroblasts, enhances NF-κB promoter activity and increases collagen contraction [30, 40].” in Line 2 to Line 10 of Page 5.

• In the innate immune system, immune cells are activated mainly by the production

of tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β1, plate-let-derived growth factor, and others.

Tnf-alpha and IL-12p40 are the main drivers of pathogenesis.

       

       Thank you very much for reviewer 2’s comment. As the reviewer 2 mentioned,

Il-12p40 has been added to the text in Section 5- (2), and the sentences has been

changed as follows;

“In the innate immune system, immune cells are activated mainly by the production of tumor necrosis factor (TNF)-α, IL-12p40, transforming growth factor (TGF)-β1, platelet-derived growth factor, and others [18, 19, 28, 30]. Monocyte-derived M1 macrophages induce inflammation and produce proinflammatory cytokines such as interferon (IFN)-γ and TNF-α. Interestingly, IL-12p40 also has been previously reported to promote M1 polarity and induce inflammation and fibrosis, which may play an important role in the pathogenesis of intestinal fibrosis in CD along with TNF-α [30, 31].” in Line 3 to Line 9 of Page 4.

• Reduce the number of references, and mention only recent reviews.

   

Thank you very much for reviewer 2’s comment. As the reviewer 2 mentioned,

　　　 I tried to cite the most recent literature as much as possible and deleted 16

papers (In this revised paper, I added 9 recent papers to create some additional sentences).

In detail, we shows deleted references and added references as follow;

(deleted references)

“Sartor, RB. Mechanisms of disease: pathogenesis of Crohn's disease and ulcerative colitis. Nat Clin Pract Gastroenterol Hepatol. 2006, 7: 390-407.”

“Burke, JP.; Mulsow, JJ.; O'Keane, C.; Docherty, NG.; Watson, RW.; O'Connell, PR. Fibrogenesis in Crohn's disease. Am J Gastroenterol. 2007, 102:439-48.”

“Safar, B.; Sands, D. Perianal Crohn's disease. Clin Colon Rectal Surg. 2007, 20: 282-93.”

“Scharl, M.; Rogler, G. Pathophysiology of fistula formation in Crohn's disease. World J Gastrointest Pathophysiol. 2014, 5: 205-12. “

“Rothfuss, KS.; Stange, EF.; Herrlinger, KR. Extraintestinal manifestations and complications in inflammatory bowel diseases. World J Gastroenterol. 2006,12: 4819-31. “

“Latella, G.; Di Gregorio, J.; Flati, V.; Rieder, F.; Lawrance, IC. Mechanisms of initiation and progression of intestinal fibrosis in IBD. Scand J Gastroenterol. 2015, 50: 53-65.”

“Duffield, JS.; Lupher, M.; Thannickal, VJ; Wynn TA. Host responses in tissue repair and fibrosis. Annu Rev Pathol. 2013, 8: 241-276.”

“Chang, CW.; Wong, JM.; Tung, CC.; Shih, IL.; Wang, HY.; Wei, SC. Intestinal stricture in Crohn's disease. Intest Res. 2015, 13:19-26.”

“Friedman, SL.; Sheppard, D.; Duffield, JS.; Violette, S. Therapy for fibrotic diseases: nearing the starting line. Friedman SL, Sheppard D, Duffield JS, Violette S. Sci Transl Med. 2013, 5: 167sr1.”

“Mifflin, RC.; Pinchuk, IV.; Saada, JI.; Powell, DW. Intestinal myofibroblasts: targets for stem cell therapy. Am J Physiol Gastrointest Liver Physiol. 2011, 300: G684-696.”

“Wynn, TA.; Barron, L. Macrophages: master regulators of inflammation and fibrosis. Semin Liver Dis. 2010, 30: 245-57.”

“Graham, MF.; Bryson, GR.; Diegelmann, RF. Transforming growth factor beta 1 selectively augments collagen synthesis by human intestinal smooth muscle cells. Gastroenterology. 1990, 99: 447-453.”

“Pohlers, D.; Brenmoehl, J.; Löffler, I.; Müller, CK.; Leipner, C.; Schultze-Mosgau, S.; Stallmach, A.; Kinne, RW.; Wolf, G. TGF-beta and fibrosis in different organs - molecular pathway imprints. Biochim Biophys Acta. 2009, 1792: 746-756.”

“Grotendorst, GR. Connective tissue growth factor: a mediator of TGF-beta action on fibroblasts. Cytokine Growth Factor Rev. 1997, 8:171-179.”

“di Mola, FF.; Di Sebastiano, P.; Gardini, A.; Innocenti, P.; Zimmermann, A.; Büchler, MW.; Friess, H. Differential expression of connective tissue growth factor in inflammatory bowel disease. Digestion. 2004, 69: 245-253.”

“Imai, J.; Kitamoto, S.; Sugihara, K.; Nagao-Kitamoto, H.; Hayashi, A.; Morhardt, TL.; Kuffa, P.; Higgins, PDR.; Barnich, N.; Kamada N. Flagellin-mediated activation of IL-33-ST2 signaling by a pathobiont promotes intestinal fibrosis. Mucosal Immunol. 2019, 12: 632-643.”

(added references)

“Rieder, F.; Fiocchi, C. Intestinal fibrosis in inflammatory bowel disease - Current knowledge and future perspectives. J Crohns Colitis. 2008, 2: 279-290.”

“Chang, CW.; Wong, JM.; Tung, CC.; Shih, IL.; Wang, HY.; Wei, SC. Intestinal stricture in Crohn's disease. Intest Res. 2015, 13:19-26.”

“Maconi, G.; Sampietro, GM.; Cristaldi, M.; Danelli, PG.; Russo, A.; Bianchi Porro, G.; Taschieri, AM. Preoperative characteristics and postoperative behavior of bowel wall on risk of recurrence after conservative surgery in Crohn's disease: a prospective study. Ann Surg. 2001, 233: 3453-52.”

“Jun, YK.; Kwon, SH.; Yoon, HT.; Park, H.; Soh, H.; Lee, HJ.; Im, JP.; Kim, JS.; Kim, JW.; Koh SJ. Toll-like receptor 4 regulates intestinal fibrosis via cytokine expression and epithelial-mesenchymal transition. Sci Rep. 2020, 10: 19867.”

“Huaux, F.; Arras, M.; Tomasi, D.; Barbarin, V.; Delos, M.; Coutelier, JP.; Vink, A.; Phan, SH.; Renauld, JC.; Lison, D. A profibrotic function of IL-12p40 in experimental pulmonary fibrosis. J Immunol. 2002,169: 2653-2661.” 

“Lu, Y.; Li, X.; Liu, S.; Zhang, Y.; Zhang, D. Toll-like Receptors and Inflammatory Bowel Disease. Front Microbiol. 2018, 9: 72.”

“Jacob, N.; Jacobs, JP.; Kumagai, K.; Ha, CWY.; Kanazawa, Y.; Lagishetty, V.; Altmayer, K.; Hamill, AM.; Von Arx, A.; Sartor, RB.; Devkota, S.; Braun, J.; Michelsen, KS.; Targan, SR.; Shih, DQ. Inflammation-independent TL1A-mediated intestinal fibrosis is dependent on the gut microbiome. Mucosal Immunol. 2018, 11: 1466-1476.”

“Zheng, L.; Zhang, X.; Chen, J.; Ichikawa, R.; Wallace, K.; Pothoulakis, C.; Koon, HW.; Targan, SR.; Shih, DQ. SUSTAINED TL1A (TNFSF15) EXPRESSION ON BOTH LYMPHOID AND MYELOID CELLS LEADS TO MILD SPONTANEOUS INTESTINAL INFLAMMATION AND FIBROSIS. Eur J Microbiol Immunol (Bp). 2013, 3: 11-20.”

“Ha, CWY.; Martin, A.; Sepich-Poore, GD.; Shi, B.; Wang, Y.; Gouin, K.; Humphrey, G.; Sanders, K.; Ratnayake, Y.; Chan, KSL.; Hendrick, G.; Caldera, JR.; Arias, C.; Moskowitz, JE.; Ho Sui, SJ.; Yang, S.; Underhill, D.; Brady, MJ.; Knott, S.; Kaihara, K.; Steinbaugh, MJ.; Li, H.; McGovern, DPB.; Knight, R.; Fleshner, P.; Devkota, S. Translocation of Viable Gut Microbiota to Mesenteric Adipose Drives Formation of Creeping Fat in Humans. Cell. 2020, 183: 666-683.e17.”

• Clarification of the involvement of specific bacteria in intestinal bacteria is also

expected to lead to the control of intestinal fibrosis.

What does authors mean by “specific bacteria in intestinal bacteria” Consider rewriting this sentence.

 

Thank you very much for the reviewer 2’s comment. As the reviewer 2 pointed out, intestinal bacteria and fibrosis are very important contents, but there are still unknown parts, so the sentence of the pointed out part was deleted and the following sentences was added as follow;

“Clarification of the involvement of intestinal bacteria is also expected to lead to the control of intestinal fibrosis, although the therapeutic application in humans remains unclear [44, 57].” in Line 24 to Line 26 of Page 6.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

In revised manuscripts, all concerns addressed satisfactory by authors. I have no more concerns for this manuscript.