Comparison of the gut microbiota composition between obese and non-obese individuals in a Japanese population, as analyzed by terminal restriction fragment length polymorphism and next-generation sequencing.
BACKGROUND
Obesity has become one of the most serious social problems in developed countries, including Japan. The relationship between the gut microbiota and obesity has recently attracted the attention of many researchers. Although the gut microbiota was long thought to contribute to obesity, the exact association remains largely unknown. We examined the human gut microbiota composition in a Japanese population in order to determine its relationship to obesity.


METHODS
Stool samples from 23 non-obese subjects (body mass index [BMI] <20 kg/m(2)) and 33 obese subjects (BMI ≥25 kg/m(2)) were collected and DNA was extracted prior to colonoscopy. After terminal restriction fragment length polymorphism (T-RFLP) analysis, samples from 10 subjects (4 non-obese and 6 obese) were selected and subjected to next-generation sequencing for species-level analysis.


RESULTS
T-RFLP analysis showed significantly reduced numbers of Bacteroidetes and a higher Firmicutes to Bacteroidetes ratio in obese subjects compared with non-obese subjects. Bacterial diversity was significantly greater in obese subjects compared with non-obese subjects. Next-generation sequencing revealed that obese and non-obese subjects had different gut microbiota compositions and that certain bacterial species were significantly associated with each group (obese: Blautia hydrogenotorophica, Coprococcus catus, Eubacterium ventriosum, Ruminococcus bromii, Ruminococcus obeum; non-obese: Bacteroides faecichinchillae, Bacteroides thetaiotaomicron, Blautia wexlerae, Clostridium bolteae, Flavonifractor plautii).


CONCLUSIONS
Gut microbial properties differ between obese and non-obese subjects in Japan, suggesting that gut microbiota composition is related to obesity.
Department of Gastroenterology, Mie Prefectural General Medical Center, 5450-132 Hinaga, Yokkaichi, Mie, 510-8561, Japan. cpkasai@tg7.so-net.ne.jp.
Chika
C
Kasai
Department of Molecular and Laboratory Medicine, Mie University School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan. kazushi@clin.medic.mie-u.ac.jp.|Department of Gastroenterology and Hepatology, Mie University School of Medicine, Tsu, Japan. kazushi@clin.medic.mie-u.ac.jp.
Kazushi
K
Sugimoto
Department of Gastroenterology, Mie Prefectural General Medical Center, 5450-132 Hinaga, Yokkaichi, Mie, 510-8561, Japan. moritani@kuwana.ne.jp.
Isao
I
Moritani
Department of Gastroenterology, Mie Prefectural General Medical Center, 5450-132 Hinaga, Yokkaichi, Mie, 510-8561, Japan. j-ichiro@cello.ocn.ne.jp.
Junichiro
J
Tanaka
Department of Gastroenterology, Mie Prefectural General Medical Center, 5450-132 Hinaga, Yokkaichi, Mie, 510-8561, Japan. yumiyama@hotmail.co.jp.
Yumi
Y
Oya
Department of Gastroenterology, Mie Prefectural General Medical Center, 5450-132 Hinaga, Yokkaichi, Mie, 510-8561, Japan. hidekazu-inoue@mie-gmc.jp.
Hidekazu
H
Inoue
Department of Molecular and Laboratory Medicine, Mie University School of Medicine, 2-174 Edobashi, Tsu, Mie, 514-8507, Japan. tameda@clin.medic.mie-u.ac.jp.|Department of Gastroenterology and Hepatology, Mie University School of Medicine, Tsu, Japan. tameda@clin.medic.mie-u.ac.jp.
Masahiko
M
Tameda
Department of Gastroenterology and Hepatology, Mie University School of Medicine, Tsu, Japan. katsuyas@clin.medic.mie-u.ac.jp.
Katsuya
K
Shiraki
Department of Cardiology and Nephrology, Tsu, Japan. mitoka@clin.medic.mie-u.ac.jp.
Masaaki
M
Ito
Department of Gastroenterology and Hepatology, Mie University School of Medicine, Tsu, Japan. ytakei@clin.medic.mie-u.ac.jp.
Yoshiyuki
Y
Takei
Department of Gastroenterology, Mie Prefectural General Medical Center, 5450-132 Hinaga, Yokkaichi, Mie, 510-8561, Japan. koujirou-takase@mie-gmc.jp.
Kojiro
K
Takase
D000328:Adult; D044466:Asian People; D041963:Bacteroidetes / Q000235:genetics / Q000302:isolation & purification; D015992:Body Mass Index; D004269:DNA, Bacterial / Q000032:analysis; D005243:Feces / Q000382:microbiology; D005260:Female; D000068536:Bacillota / Q000235:genetics / Q000302:isolation & purification; D000069196:Gastrointestinal Microbiome / Q000235:genetics*; D041981:Gastrointestinal Tract / Q000382:microbiology*; D006801:Humans; D007564:Japan; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000382:microbiology*; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA / Q000379:methods
D004269:DNA, Bacterial