Open Access Table 3 Clinical and laboratory data regarding obesity/ significantly decreased in the patients after eradication T2DM therapy. While we still need to clarify the relationship Eradication therapy between changes in the B: F ratio and the ghrelin level after the treatment with antimicrobials, changes in the S1(n=20)$3(n=20) P value ut microbiota, such as B: F ratio and abundance of both Body weight(kg) 52.9 53.9 dobacterium and Faecalibacterium, might cause a reduc- (51.6-70.2)”(49.7-70.8) tion in the plasma level of ghrelin, as the direct and earliest= Percent body fat(%)26.7±8.3t26.4±8.10.43 Body mass index 23.0=3. 4 22.9=3.6 0.26 hormone-secreting system. Moreover, Lin et aP reported S Serum triglycerides 80.5 109.0 0.35 that butyrate, one of the major short-chain fatty acids (mg/dl (698-1393)(5.8-1553) formed by gut microbiota such as Faecalibacterium, whose Fasting blood 0.99 abundance actually enlarged in the present study, reduced an glucose(mg/dL)(91-102) (87-103) the plasma ghrelin level in the murine system. It has been a Insulin(ulU/mL) 4.48 3.17 (262-681)(1.86-9.56) the host energy balance by affecting the energy yield from 9 HOMA-R 1.02 2.05 and modulating diet-derIved compounds that alter 3 (0.62-1.99)(0.42-3.14) the host metabolic pathway. Taken together, we suggestec HbA1C(NGSP % 5.6 5.6 0.10 that ghrelin, an appetite-regulating hormone of stomach (53-6.0)(54-5.9) origin, might be a novel factor by which the gut microbiota a Adiponectin(ug/mL)9.2 10.4 0.41 affect the energy balance of the host. Furthermore, bot (7.1-128)(6.5-14.1) the gut microbiota composition and the plasma ghrelin 8 CRP (ng/mL) 0.18 R (187-1083)(202-1180) visceral obesity or insulin resistance 9 yl- ghrelin89.8±40.877.6±36.70.14 Why such a 'lean phenotype was found in both the o gut microbiota composition and plasma ghrelin level at Z 3months after the eradication therapy in the present study Active ghrelin 0.003 (6-10.5) (0-6.25) Leptin(ng/mL) 0.03 Months after the eradication therapy was also reported in s bears further investigation. A lower plasma ghrelin level at 8.1 8.5 Japanese patients in other studies. b In contrast, however, 9 58-13.0)(5.9-152) a decrease in the B: F ratio, a phenotype of obesity, was observed at 6months posteradication, which is 3months later than the time-point for our assay. This suggests that reactive protein; HbAlc, glycated haemoglobin type 2 diabetes mellitus HOMA-R, homeostasis model an assay at 3months after the termination of therapy might assessment-insulin resistance be too early to accurately assess the resilience of gut micro- a biota to reversely fluctuate towards a 'fat' phenotype in level is regulated by multiple factors, including food intake, vulnerable patients, which may have increased the ghrelin body weight and gastric ghrelin production. Because the level and then the body weight later. As such, the short dura eradication of H. pylori is known to increase the produc- tion of follow-up after the eradication therapy may be one s ion of ghrelin in the gastric mucosa, it appeared unlikely limitation associated with the present study that the elimination of H pylori caused the reduction in the plasma ghrelin level. Indeed, such reduction in the plasma odin inn ih Hl, H si d no om red binet a, pyominnticne pt nds cn dergoing ghrelin was observed even in the three patients in the performed bacteriological, genetical and statistical analyses YK was involved in the 5 present study who failed H. prylonieradication therapy. There- study design and drafting the manuscript. AtT was involved in the study design and fore, some event other than the eradication of H. pylori itself data interpretation. may have caused the decrease in the plasma ghrelin level Funding This study was funded by Meji Co, Ltd (okyo, Japan) after eradication therapy in the present study, while it still Competing interests None declared needs further studies using sufficient number of H. pyloni-in- Ethics approval The ethics committee of Tokai University Hospital approved the 2 fected subjects to exclude the H. pylori infection as a cause of study(15R-160) the plasma ghrelin reduction Provenance and peer review Not commissioned; extermally peer reviewed. Queipo-Ortuno et af highlighted the association Open Access This is an Open Access article distributed in accordance with the between the gut microbiota and appetite-regulating Creative Commons Attribution Non Commercial(CC BY-NC4.0)license, which hormones using rat models with different nutritional permits others to distribute, remix, adapt, build upon this work non-commercially, onditions and levels of physical activity. In their study, and license their derivative works on different terms, provided the original work i plasmaghrelinlevelwassignificantlycorrelatedwiththelicenses/dy-ncOeuseisnon-commercial.SEe:http:/lcreativecommons.org/ properly cited and quantity of several kinds of bacteria, including Bifidobac- aRticle authors) for their employer(s) unless otherwise stated in the text of the terium and Bacteroides. Also in the present study, both the article) 2017. All rights reserved. No commercial use is permitted unless otherwise plasma ghrelin level and the abundance of Bifidobacte expressly granted. Yanagi H, et al. BMJ Open Gastro 2017: 4: e000182 doi 10. 1136/bmjgast-2017-000187Yanagi H, et al. BMJ Open Gastro 2017;4:e000182. doi:10.1136/bmjgast-2017-000182 7 Open Access level is regulated by multiple factors, including food intake, body weight and gastric ghrelin production.23 Because the eradication of H. pylori is known to increase the produc￾tion of ghrelin in the gastric mucosa,5 it appeared unlikely that the elimination of H. pylori caused the reduction in the plasma ghrelin level. Indeed, such reduction in the plasma ghrelin was observed even in the three patients in the present study who failed H. pylori eradication therapy. There￾fore, some event other than the eradication of H. pylori itself may have caused the decrease in the plasma ghrelin level after eradication therapy in the present study, while it still needs further studies using sufficient number of H. pylori-in￾fected subjects to exclude the H. pylori infection as a cause of the plasma ghrelin reduction. Queipo-Ortuño et al24 highlighted the association between the gut microbiota and appetite-regulating hormones using rat models with different nutritional conditions and levels of physical activity. In their study, plasma ghrelin level was significantly correlated with the quantity of several kinds of bacteria, including Bifidobac￾terium and Bacteroides. Also in the present study, both the plasma ghrelin level and the abundance of Bifidobacterium significantly decreased in the patients after eradication therapy. While we still need to clarify the relationship between changes in the B:F ratio and the ghrelin level after the treatment with antimicrobials, changes in the gut microbiota, such as B:F ratio and abundance of both Bifidobacterium and Faecalibacterium, might cause a reduc￾tion in the plasma level of ghrelin, as the direct and earliest target of antimicrobials would be the microbiota, not the hormone-secreting system. Moreover, Lin et al25 reported that butyrate, one of the major short-chain fatty acids formed by gut microbiota such as Faecalibacterium, whose abundance actually enlarged in the present study, reduced the plasma ghrelin level in the murine system. It has been reported that the gut microbiota significantly influence the host energy balance by affecting the energy yield from foods and modulating diet-derived compounds that alter the host metabolic pathway.8 Taken together, we suggested that ghrelin, an appetite-regulating hormone of stomach origin, might be a novel factor by which the gut microbiota affect the energy balance of the host. Furthermore, both the gut microbiota composition and the plasma ghrelin level might be used as an earliest biomarker to foresee the visceral obesity or insulin resistance. Why such a ‘lean’ phenotype was found in both the gut microbiota composition and plasma ghrelin level at 3months after the eradication therapy in the present study bears further investigation. A lower plasma ghrelin level at 3months after the eradication therapy was also reported in Japanese patients in other studies.5 6 In contrast, however, a decrease in the B:F ratio, a phenotype of obesity, was observed at 6months posteradication, which is 3months later than the time-point for our assay.18 This suggests that an assay at 3months after the termination of therapy might be too early to accurately assess the resilience of gut micro￾biota to reversely fluctuate towards a ‘fat’ phenotype in vulnerable patients, which may have increased the ghrelin level and then the body weight later. As such, the short dura￾tion of follow-up after the eradication therapy may be one limitation associated with the present study. Contributors HY, AyT and MM recruited the H. pylori-infected patients undergoing eradication therapy and performed biochemical examinations. ST and GO performed bacteriological, genetical and statistical analyses. YK was involved in the study design and drafting the manuscript. AtT was involved in the study design and data interpretation. Funding This study was funded by Meiji Co, Ltd (Tokyo, Japan). Competing interests None declared. Ethics approval The ethics committee of Tokai University Hospital approved the study (15R-160). Provenance and peer review Not commissioned; externally peer reviewed. Open Access This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/ licenses/by-nc/4.0/ © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted. Table 3 Clinical and laboratory data regarding obesity/ T2DM Eradication therapy S1 (n=20) S3 (n=20) P value Body weight (kg) 52.9 (51.6–70.2)* 53.9 (49.7–70.8) 0.35 Percent body fat (%) 26.7±8.3† 26.4±8.1 0.43 Body mass index 23.0±3.4 22.9±3.6 0.26 Serum triglycerides (mg/dL) 80.5 (69.8–139.3) 109.0 (65.8–155.3) 0.35 Fasting blood glucose (mg/dL) 105 (91–102) 108 (87–103) 0.99 Insulin (μIU/mL) 4.48 (2.62–6.81) 3.17 (1.86–9.56) 0.93 HOMA-R 1.02 (0.62–1.99) 2.05 (0.42–3.14) 0.78 HbA1c (NGSP %) 5.6 (5.3–6.0) 5.6 (5.4–5.9) 0.10 Adiponectin (μg/mL) 9.2 (7.1–12.8) 10.4 (6.5–14.1) 0.41 CRP (ng/mL) 511 (187–1083) 408 (202–1180) 0.18 Desacyl – ghrelin (fmol/L) 89.8±40.8 77.6±36.7 0.14 Active ghrelin (fmol/L) 8 (6–10.5) 5 (0–6.25) 0.003 Leptin (ng/mL) 8.1 (5.8–13.0) 8.5 (5.9–15.2) 0.03 *Median (IQR). †Mean±SD. CRP, C reactive protein; HbA1c, glycated haemoglobin; T2DM, type 2 diabetes mellitus. HOMA-R, homeostasis model assessment-insulin resistance.  copyright. on 4 July 2018 by guest. 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