Dear Dr. XXX,Thank you for arranging a timely review for our manuscript. We are pleased to know that our study is of general interest for the readers of NUTRITION. We have carefully evaluated the reviewers’ critical comments and thoughtful suggestions, r esponded to these suggestions point-by-point, and revised the manuscript accordingly. All changes made to the text are in red so that they may be easily identified. With regard to the reviewers’ comments and suggestions, we wish to reply as follows:Enclosures:(1)Correspondences to your reviewers;(2)One copy of the revised manuscript;(3)A floppy disk containing the revised manuscript.(4)Copyright assignmentTo reviewer#11.The author should add a few review articles on ghrelin for readers in theIntroduction.We added two reviews in our revised manuscript.2.The increase in ghrelin levels do not necessary indicate that weight loss in diseaseis well compensated (Introduction and Discussion). This may be interpreted to be insufficient to recover to the previous body weight.There is possibility that the increase in ghrelin levels may result from the insufficient to recover to the previous body weight, but it is more likely that the increase in ghrelin level indicate that weight loss in disease is well compensated.Shimizu et al1 reported that baseline plasma ghrelin level was significantly higher in cachectic patients with lung cancer than in noncachectic patients and control subjects. As weight loss is a chronic process and ghrelin levels may change more rapid than weight loss, the increase in ghrelin in those chronic diseases is unlikely result from the insufficient to recover to the previous body weight. Moreover, this author also reported that follow-up plasma ghrelin level increased in the presence of anorexia after chemotherapy, which further suggests that the increase ghrelin level may represent a compensatory mechanism under catabolic–anabolic imbalance in cachectic patients with lung cancer1.3.The authors should refer to the original report that IL-1b decrease plasma ghrelinlevels(Gastroentelorogy 120:337-345,2001)We referred this article as the reviewer suggested. In fact, this is a mistake of us. Many thanks for the reviewer’s suggestion.4.Ref. 13 dose not include data on ghrelin.We are so sorry to make this mistake for citing the Ref.13. We replaced the reference in the paper.5.There is no report that desacyl ghrelin stimulates food intake. It is the consensusat present acyl ghrelin is involved in feeding response to starvation. Therefore, the authors should be careful about their interpretation described in the last paragraph in page 10.We made it clear in the paper that ghrelin has two isoforms (“active”and “inactive”). Only the “active”isoform is involved in feeding response tostarvation. But the “inactive”isoform has other activities like anti-proliferative activity on tumor cell lines as described in the manuscript.To reviewer#2Major comments1.Earlier studies have shown that circulating ghrelin level is increased inunderweight patients with CHF, lung cancer, and liver cirrhosis. In the present study, however, plasma ghrelin level was decreased despite a significant weight loss in COPD. In addition, earlier studies have reported that circulating ghrelin correlated positively with BMI in patients with CHF and lung cancer. However, the present study demonstrated that plasma ghrelin level correlated positively with BMI in COPD patients. Thus, there are considerable discrepancies between the present study and earlier studies. These discrepancies should be discussed in detail. The author also stated the regulation of ghrelin secretion was disturbed in COPD patients. However, they did not clarify this mechanism.We stated that the role of ghrelin in patients with COPD may be different from its role in CHF, cancer and liver cirrhosis and discussed this difference in the last paragraph of page 9.Following the reviewer’s suggestion, we added that “plasma ghrelin correlated positively with percent predicted residual volume and residual volume/total lung capacity ratio”as the evidence for further supporting that respiratory abnormalities may take part in the regulation of plasma ghrelin levels.2.The authors demonstrated that plasma ghrelin level correlated negatively withplasma TND-a and CRP in COPD patients. However, Nagaya et al. have shown that plasma ghrelin level correlates positively with plasma TNF-a level in patients with CHF. This discrepancy should be discussed.According to the reviewer indicated, we discussed this discrepancy in the second paragraph of page 9.3.The author stated that respiratory abnormalities may take part in the regulation ofplasma ghrelin level in COPD. The authors should describle the relationship between plasma ghrelin level and pulmonary function in COPD.There are evidences that respiratory abnormalities may take part in the regulation of plasma ghrelin level in lung diseases with respiratory abnormalities2,3. As our study was designed to investigate whether the plasma ghrelin levels are increased or decreased in COPD and whether the plasma ghrelin levels relates to the increased systemic inflammation in those patients, so we didn’t analysis the relationship between plasma ghrelin level and pulmonary function.Minor comments1.Circulating ghrelin level exhibits a circadian rhythm. Therefore, the authorsshould describle the limitation of their measurement of ghrelin in single samples.It’s true that circulating ghrelin level exhibits a circadian rhythm and to monitor the ghrelin levels in different time points is better than just measured a single sample. However, we collected the samples at the fasting state (from 9:00 p.m. on the previous night.) by venipuncture at 7:00 a.m. as most studies did2,4. Soour results can exclude the possibility that the difference between groups was result from the circadian rhythm of ghrelin and are well compared with other studies.2.In the Results section, plasma ghrelin level in healthy controls was different withthat in 0.25+0.22ng/ml, whereas, in Figure 1A, it was approximately 1.8ng/ml.We fixed this in our revised manuscript. We are so sorry to make this mistake.To reviewer#31.About the paper of Itoh et al in AJRCC.As the reviewer said, the study by Itoh et al was not published when the current manuscript were submitted. We discussed the difference between the findings of their study and our study in revised manuscript.2.AbstractConclusion: “plasma ghrelin decreased in COPD”. This sounds like the authors have followed subjects for a long time and that the diagnosis COPD was conformed, the plasma ghrelin decreased. This was however not the aim nor the case-a reformulation is necessary.We fixed this as the reviewer suggested in our revised manuscript.3.Introduction(1)Page 2. Ref.1. is a letter to the editor in Br J Nutr and is a commentconcering an earlier published paper. It is not a reference that support the statement. Several other references exist in the literature to be used instead.Thanks for the reviewer’s suggestion. We replaced this reference by other one.(2)Page 2, line 5. “To understand weight loss mechanisms in this disease may behelpful to improve quality of life in these patients”. Do you really think that if we researchers understand the mechanisms that automatically would make the patients happier?We replaced this sentence with “To understand weight loss mechanisms in this disease may be helpful to combat weight loss in these patients”4.Methods(1)Patients: How were the patient and control subjects selected?The authors state that none of the control subjects was taking and medications-was that also the case for the patients?That was also the case for the patients. In fact, most of the COPD patients in China do not take any medications when the disease is clinically stable because of economic reason.Page 4, line 2. A short description of ATS criteria would be helpful for readers who are not familiar with those criteria.As those criteria are widely used by researcher and physicians, we did not describe them in our paper as some paper did. If you think it is necessary to do so, we may add a short description.Page4, line3, what do you mean by “other diseases”? COPD patients mostoften have a lot of other diseases.We are so sorry to mis-express this - we just means that those patients did not have the disease that known to affect the plasma ghrelin level. We fixed it in our revised manuscript.Page 4, line 5. If I understand it correctly, none of the COPD patients were smokers or ex-smokers, i.e. another reason exists for their COPD. Cigarette smoking is the main cause of COPD, but here you have studied patients having other reasons for the disease. What dose this mean regarding the representativity of the study group?Could it affect the results in some way?Smoking increases the plasma ghrelin level5. It is difficult for us to define “ex-smokers” because there is no study about that whether the ex-smoking will affect the plasma ghrelin level or not. This may lead to the representativity problem. However, those patients in our study still lost the weight and had system inflammation as most COPD patients did. Further study should be designed to investigate the effect of ex-smoking on plasma ghrelin level.Page 4, line 6.Why do the authors refer to Whatmore et al? That study investigated ghrelin in healthy adolescents and has nothing to do with factor known to affect serum ghrelin level.We are sorry to make this mistake. We replaced this reference.(2)Body compositionPage 4, last line – page 5, line1. The deuterium dilution study performed by Baarends et al was using arm – to – foot bioelectrical impedance spectroscopy. In the current manuscript the foot – to – foot bioelectrical impedance assessment is used. The readers are lead to believe that the foot – to – foot BIA is also validated with deuterium dilution in COPD patients, which I think is not the case.Thanks for the carefulness of the reviewer. However, there are still evidences that our method is well correlated with DEXA6and arm –to –foot bioelectrical impedance7, so it is appropriate to use this method in our study. However, because those sentences will lead to the confusion, we deleted them in revised manuscript according to suggestion of the reviewer.Page 5, line 4. The %fat was calculated by the machine. It should be stated on which material these calculations are based on – healthy subject? –young or old? – How many.According to the instruction of the manufactory, we selected the standard model for this calculation (the other model was athletic). We stated this in the revised manuscript.(3)StatisticalA reference by Scols et al is used to strengthen the use of values below the detection limit and the use of log. Other reasons need to be provided. What if Schols et al did a statistical error using values that were below the detection limit? There do exist statistical reasonsfor log the values –do they exist in this manuscript?It’s very important to select a suitable statistical method for process the data. There are 6 data below the detection limit in ghrelin and 1 data in leptin. Ifthese data were discarded, it may increase the possibility of type two error as lower ghrelin levels were exclude. However, if the data were analyzed originally, it may increase the possibility of type one error as they below the detection limit.So it is reasonable to adopt the method used by Schols et al.As to log transformation, we added the necessary information in the text according to the opinion of the reviewer.5.DiscussionPage 8. line 2-3. COPD patients had lower ghrelin levels compared to the control subjects. Did the control subjects have “normal” ghrelin values?We selected seventeen age-matched healthy males as control subjects.Those subjects were healthy. So we can take their ghrelin levels as “normal”ghrelin values. However, we think true “normal ghrelin values” should be based on large population study.Page9. line 18. Following “CHF, cancer and liver cirrhosis” a reference is needed here.We added references as the reviewer suggested.Page9. last line.ghrelin instead of gherlin.We fixed it.Page 11. Delete the summary, it is the same as the conclusion in the abstract.We wrote the summary according to the guideline for author of the journal. If you think the summary should be cut, we may delete it.6.ReferenceAs mentioned above, some of the references are not appropriate. They should be replaced by more appropriate and explanatory references.Many thanks for the reviewer’s suggestion. We replaced those references in the revised manuscript.References:1. Shimizu, Y., Nagaya, N., Isobe, T., et al. Increased plasma ghrelin level in lung cancer cachexia. Clin Cancer Res 2003; 9: 7742. Itoh, T., Nagaya, N., Yoshikawa, M., et al. Elevated Plasma Ghrelin Level in Underweight Patients with Chronic Obstructive Pulmonary Disease. Am J Respir Crit Care Med 2004;3. Haqq, A. M., Stadler, D. D., Jackson, R. H., et al. Effects of growth hormone on pulmonary function, sleep quality, behavior, cognition, growth velocity, body composition, and resting energy expenditure in Prader-Willi syndrome. J Clin Endocrinol Metab 2003; 88: 22064. Nagaya, N., Uematsu, M., Kojima, M., et al. Elevated circulating level of ghrelin in cachexia associated with chronic heart failure: relationships between ghrelin and anabolic/catabolic factors. Circulation 2001; 104: 20345. Fagerberg, B., Hulten, L. M.,Hulthe, J. Plasma ghrelin, body fat, insulin resistance, and smoking in clinically healthy men: the atherosclerosis and insulin resistance study. Metabolism 2003; 52: 14606. Tyrrell, V. J., Richards, G., Hofman, P., et al. Foot-to-foot bioelectrical impedance analysis: a valuable tool for the measurement of body composition in children. Int J Obes Relat Metab Disord2001; 25: 2737. Nunez, C., Gallagher, D., Visser, M., et al. Bioimpedance analysis: evaluation of leg-to-leg system based on pressure contact footpad electrodes. Med Sci Sports Exerc 1997; 29: 524一篇稿子从酝酿到成型历经艰辛，投出去之后又是漫长的等待，好容易收到编辑的回信，得到的往往又是审稿人不留情面的一顿狂批。
