Soluble Receptor of Advanced Glycation End-Products (sRAGE) in Pediatric Asthma: A Prospective Study in 68 Children Aged 7 Years

Round 1

Reviewer 1 Report

This study analyzed and explored plasma sRAGE levels in asthmatic and healthy children aged 7 years. It is concluded that no difference was observed in plasma sRAGE levels in asthmatic children in well treated and controlled population, and environmental exposure could have an impact on its levels. But there are still some shortcomings, my suggestions are as follows：

1. In the “Abstract – Background” section, The description of why this study was done was unclear.
2. Authors need to be more specific about this study's main contribution or innovation in their field.
3. The letter p of P-value format in the “Abstract” and “Results” sections needs to be unified: some were in italics, some were not. e.g. p = 0.525, p = 0.007
4. In the “Discussion” section, please insert a part discussing the impact of this study. What research can benefit or inspire from this research, and what problems does this research help solve?

Author Response

~ Comment 1] In the “Abstract – Background” section, The description of why this study was done was unclear.

“Abstract: Background:  Asthma is a chronic inflammation airways inflammatory common in children. The soluble receptor for advanced glycation end products (sRAGE) is a blood bi-omarker of pulmonary injury and inflammation. The measurement of its blood concentration is a prognostic factor in acute respiratory distress syndrome (ARDS) and could useful in asthma” (words 51)

~ Answer 1] As requested by the reviewer we modify the abstract to explain the rationale of the study. Revised Abstract: Background:  “Asthma is a chronic inflammatory disease of the airways common in children. Soluble advanced glycation end-product receptor (sRAGE) is a blood biomarker of lung damage and inflammation. We sought to determine whether it could also be a biomarker in childhood asthma.” (44 words)

~ Comments 1 And 4] Authors need to be more specific about this study's main contribution or innovation in their field.

~ Answers 1 and 4] The authors added a section at the end of the discussion to highlight what the results of this study bring to the knowledge of childhood asthma.

New section “Our study shows no increase in the plasma level of sRAGE in pediatric asthma. sRAGE does not therefore appear to be a diagnostic marker for childhood asthma. However, in our study, all the children with asthma were taking inhaled corticosteroids and had normal lung function. If an effective treatment reduces bronchial inflammation, then it can normalize the level of sRAGE. We thus hypothesize that serum sRAGE assay could be a good biomarker of well-controlled asthma. It would then be useful to measure the plasma level of sRAGE in the follow-up of children with asthma: a normal level could be the indicator of controlled asthma and so could help adapt therapy. This is innovative because currently no blood biomarker is routinely used to monitor children with asthma.”

~Comment 3] The letter p of P-value format in the “Abstract” and “Results” sections needs to be unified: some were in italics, some were not. e.g. p = 0.525, p = 0.007

~Answer 3] Th authors have corrected this point directly in the text.

Reviewer 2 Report

The Manuscript entitled "Soluble Receptor of Advanced Glycation End-Products (sRAGE) in Pediatric Asthma: a Prospective Study in 68 Children Aged 7 Years", Julie et al., discusses about respiratory problem, 'Asthma' which is a chronic inflammation of airways and is most common in children. The soluble receptor for advanced glycation end products (sRAGE) is a blood biomarker of many diseases including the pulmonary injury and inflammation. The measurement of its blood concentration is a prognostic factor in acute respiratory distress syndrome and could be useful in asthma. In the current study authors did not find the difference in the serum levels of sRAGE in healthy and asthmatic children. 

overall the MS is good, however this reviewer has certain queries-

Major Comments:

comment 1. Authors are advised to look into the English language and grammatical errors throughout the manuscript.

Comment 2. Introduction- Page 2: "The receptor for advanced glycation end products (RAGE) is a trans-membranous receptor present in large quantities in the lungs, particularly in alveolar epithelial type I cells" [2,3]. The references cited here are more than a decade older. The references which are cited should be from latest one, if citing for the recent research development, however for basic work one may cite as old as its age. Therefore, ref. 2 & 3 should be replaced with recent one's, like; e.g., 

ref. a. Oxidation, glycation and glycoxidation—The vicious cycle and lung cancer. Seminars in Cancer Biology 2018 (Vol. 49, pp. 29-36). 

ref. b. AGEs, RAGEs and s-RAGE; friend or foe for cancer. Seminars in Cancer Biology (Vol. 49, pp. 44-55).

Similarly ref. 5 should be replaced with recent one like,

ref. c. A receptor of the immunoglobulin superfamily regulates adaptive thermogenesis. Cell reports. 2019; 28(3):773-91.

And ref. 7 should be replaced with-

ref. d.  The receptor for advanced glycation end products: A fuel to pancreatic cancer. Seminars in Cancer Biology 2017 (Vol. 49, pp. 37-43).

Comment 3. The blood samples were freezed after centrifugation and aliquoting.  The stability of the collection was annually tested. Authors need to clarify the method of stability tests performed in order to see after freezing at -80 deg.C.

Comment 4. What is the detection limit 78 pg/mL in sRAGE estimations mean as described in material and methods by the author?

comment 5. Plasma sRAGE levels didn’t not differ between asthmatic children and healthy children: 1875 (+_ 472) pg/mL versus 1794 (+_418) pg/mL respectively. Why? Authors encouraged highlight this in discussion section.

comment 6. Conclusion should be re-written which should be more specific and precise.

Minor comment:

1. Authors are advised to give 'p' value in terms of greater or equal to symbol to better understand the statistical significance of table 1.

Author Response

~Comment 1] Authors are advised to look into the English language and grammatical errors throughout the manuscript.

Answer 1] The authors have resubmitted all manuscripts to a professional translator and corrections have been made to the documents.

~Comment 2] Introduction- Page 2: "The receptor for advanced glycation end products (RAGE) is a trans-membranous receptor present in large quantities in the lungs, particularly in alveolar epithelial type I cells" [2,3]. The references cited here are more than a decade older. The references which are cited should be from latest one, if citing for the recent research development, however for basic work one may cite as old as its age. Therefore, ref. 2 & 3 should be replaced with recent one's, like; e.g.,

ref. a. Oxidation, glycation and glycoxidation—The vicious cycle and lung cancer. Seminars in Cancer Biology 2018 (Vol. 49, pp. 29-36).

ref. b. AGEs, RAGEs and s-RAGE; friend or foe for cancer. Seminars in Cancer Biology (Vol. 49, pp. 44-55).

Similarly ref. 5 should be replaced with recent one like,

ref. c. A receptor of the immunoglobulin superfamily regulates adaptive thermogenesis. Cell reports. 2019; 28(3):773-91.

And ref. 7 should be replaced with-

ref. d.  The receptor for advanced glycation end products: A fuel to pancreatic cancer. Seminars in Cancer Biology 2017 (Vol. 49, pp. 37-43).

 Answer 2] The authors acknowledge the need for more recent references and so have replaced 2,3,5,7 by those suggested by the reviewer.

~ Comment 3] The blood samples were freezed after centrifugation and aliquoting.  The stability of the collection was annually tested. Authors need to clarify the method of stability tests performed in order to see after freezing at -80 deg.C.

Answer 3] As certified ISO EN 15189 (French National Accreditation for the laboratory) the Biochemistry Department developed pre-analytical process to guaranty the quality of the results for the assays. In this way, to study the stability of the collection, we realized some supplementary aliquots at the beginning of this collection. The blood concentration of a referent and very stable protein at - 80°C (i.e. albumin) was assayed at the beginning of the establishment. Annually, an aliquot was checked in terms of albumin concentration. For the samples of this collection, the stability during the- 80°C freezing was established by an absence of statistical variation of albumin concentration.

~Comment 4] What is the detection limit 78 pg/mL in sRAGE estimations mean as described in material and methods by the author?

Answer 4] 78 pg/ml is the threshold concentration (limit of quantification) that can be measured with the commercial kit.The Human RAGE Quantikine ELISA Kit from Bio-Techne R&D Systems was used, with a rated assay range of 78.0–5000 pg/mL and a sensitivity of 16.14 pg/mL (limit of detection).

~Comment 5] Plasma sRAGE levels didn’t not differ between asthmatic children and healthy children: 1875 (+_ 472) pg/mL versus 1794 (+_418) pg/mL respectively. Why? Authors encouraged highlight this in discussion section.

Answer 5] The authors have added a specific section at the end of the discussion about these results and what they imply. Additional paragraph: “Our study shows no increase in the plasma level of sRAGE in pediatric asthma. sRAGE does not therefore appear to be a diagnostic marker for childhood asthma. However, in our study, all the children with asthma were taking inhaled corticosteroids and had normal lung function. If an effective treatment reduces bronchial inflammation, then it can normalize the level of sRAGE. We therefore hypothesize that serum sRAGE assay could be a good biomarker of well-controlled asthma. It would then be useful to measure the plasma level of sRAGE in the follow-up of children with asthma: a normal level could be the indicator of controlled asthma and so could help adapt therapy. This is innovative because currently no blood biomarker is routinely used to monitor children with asthma.”

~Comment 6] Conclusion should be re-written which should be more specific and precise.

Answer 6] The authors have re-written the conclusion. Revised conclusion: “Our study shows that plasma sRAGE is not a marker for the diagnosis of asthma in children and that it does not vary according to the patient's atopic status. The normal level found in well-treated patients with asthma suggests that it would be a good biomarker of controlled asthma and could be useful in monitoring, but further studies are needed to explore plasma sRAGE in uncontrolled asthma.

~ Comment 7] Authors are advised to give 'p' value in terms of greater or equal to symbol to better understand the statistical significance of table 1.

Answer 7] The authors have added * in Table 1 for means with p ≤ 0.05 to make the results more explicit.

Reviewer 3 Report

This study showed no significant difference between the serum levels of sRAGE in  healthy and asthmatic children; but most of the asthmatic children were well treated and  controlled.

By reducing bronchial inflammation, the use of inhaled corticosteroids at an efficient dose may normalize serum levels of sRAGE in our population.

Active airway  inflammation was correlated with low sRAGE levels, as shown in children exposed to  tobacco smoking and urban pollution.

This argues for an anti-inflammatory action by  blocking the RAGE inflammatory cascade in the lungs.

Comments for author File: Comments.pdf

Author Response

Thank you for reviewing our article and verifying that it was valid for publication in this area.

Round 2

Reviewer 1 Report

Reviewer 2 Report

No further comments. Manuscript has been revised appropriately.

Decision- Accept.