BackgroundObesity 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.MethodsStool samples from 23 non-obese subjects (body mass index [BMI] <20 kg/m2) and 33 obese subjects (BMI ≥25 kg/m2) 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.ResultsT-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).ConclusionGut microbial properties differ between obese and non-obese subjects in Japan, suggesting that gut microbiota composition is related to obesity.Electronic supplementary materialThe online version of this article (doi:10.1186/s12876-015-0330-2) contains supplementary material, which is available to authorized users.

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths in Japan. The etiology of CRC has been linked to numerous factors including genetic mutation, diet, life style, inflammation, and recently, the gut microbiota. However, CRC-associated gut microbiota is still largely unexamined. This study used terminal restriction fragment length polymorphism (T-RFLP) and next-generation sequencing (NGS) to analyze and compare gut microbiota of Japanese control subjects and Japanese patients with carcinoma in adenoma. Stool samples were collected from 49 control subjects, 50 patients with colon adenoma, and 9 patients with colorectal cancer (3/9 with invasive cancer and 6/9 with carcinoma in adenoma) immediately before colonoscopy; DNA was extracted from each stool sample. Based on T-RFLP analysis, 12 subjects (six control and six carcinoma in adenoma subjects) were selected; their samples were used for NGS and species-level analysis. T-RFLP analysis showed no significant differences in bacterial population between control, adenoma and cancer groups. However, NGS revealed that i), control and carcinoma in adenoma subjects had different gut microbiota compositions, ii), one bacterial genus (Slackia) was significantly associated with the control group and four bacterial genera (Actinomyces, Atopobium, Fusobacterium, and Haemophilus) were significantly associated with the carcinoma-in-adenoma group, and iii), several bacterial species were significantly associated with each type (control: Eubacterium coprostanoligens; carcinoma in adenoma: Actinomyces odontolyticus, Bacteroides fragiles, Clostridium nexile, Fusobacterium varium, Haemophilus parainfluenzae, Prevotella stercorea, Streptococcus gordonii, and Veillonella dispar). Gut microbial properties differ between control subjects and carcinoma-in-adenoma patients in this Japanese population, suggesting that gut microbiota is related to CRC prevention and development.

Background Helicobacter pylori (H. pylori) infection and eradication therapy have been known to influence gastric ghrelin and leptin secretion, which may lead to weight gain. However, the exact relationship between plasma ghrelin/leptin levels and H. pylori infection has remained controversial. The aim of this study was to investigate plasma ghrelin and leptin levels in H. pylori-positive and -negative patients, to compare the two levels of the hormones before and after H. pylori eradication, and to examine the correlation between body mass index (BMI) and active ghrelin or leptin levels, as well as that between atrophic pattern and active ghrelin or leptin levels.MethodsSeventy-two H. pylori-positive patients who underwent upper gastrointestinal endoscopy, 46 diagnosed as having peptic ulcer and 26 as atrophic gastritis, were enrolled. Control samples were obtained from 15 healthy H. pylori-negative volunteers. The extent of atrophic change of the gastric mucosa was assessed endoscopically. Body weight was measured and blood was collected before and 12 weeks after H. pylori eradication therapy. Blood samples were taken between 8 and 10 AM after an overnight fast.ResultsPlasma ghrelin levels were significantly lower in H. pylori-positive patients than in H. pylori-negative patients. In particular, plasma active ghrelin levels were significantly lower in patients with gastritis compared with patients with peptic ulcer. Plasma ghrelin levels decreased after H. pylori eradication in both peptic ulcer and gastritis patients, while plasma leptin levels increased only in peptic ulcer patients. Plasma leptin levels and BMI were positively correlated, and active ghrelin levels and atrophic pattern were weakly negatively correlated in peptic ulcer patients.Conclusion H. pylori infection and eradication therapy may affect circulating ghrelin/leptin levels. This finding suggests a relationship between gastric mucosal injury induced by H. pylori infection and changes in plasma ghrelin and leptin levels.

Although thrombosis in coronavirus disease 2019 (COVID-19) infection has attracted attention, the mechanism underlying its development remains unclear. The relationship between platelet activation and the severity of COVID-19 infection was compared with that involving other infections. Plasma soluble C-type lectin-like receptor 2 (sCLEC-2) levels were measured in 46 patients with COVID-19 infection and in 127 patients with other infections. The plasma sCLEC-2 levels in patients with COVID-19 infection {median (25th, 75th percentile), 489 (355, 668) ng/L} were significantly higher (p < 0.001) in comparison to patients suffering from other pneumonia {276 (183, 459) ng/L}, and the plasma sCLEC-2 levels of COVID-19 patients with severe {641 (406, 781) ng/L} or critical illness {776 (627, 860) ng/L} were significantly higher (p < 0.01, respectively) in comparison to those with mild illness {375 (278, 484) ng/L}. The ratio of the sCLEC-2 levels to platelets in COVID-19 patients with critical illness of infection was significantly higher (p < 0.01, p < 0.001 and p < 0.05, respectively) in comparison to COVID-19 patients with mild, moderate or severe illness. Plasma sCLEC-2 levels were significantly higher in patients with COVID-19 infection than in those with other infections, suggesting that platelet activation is triggered and facilitated by COVID-19 infection.

D-dimer is a biomarker of thrombosis and recently been considered to predict a poor outcome in patients with infectious diseases. Plasma D-dimer levels were measured in critically ill patients to examine their relationship with the poor outcome. The plasma D-dimer levels were markedly higher in the patients with various underlying disease especially venous thromboembolism in comparison to those without severe underlying diseases. The plasma D-dimer levels in non-survivors were significantly higher than those in survivors. In a receiver operating characteristic analysis, the area under the curve was high for the disseminated intravascular coagulation (DIC) score, the D-dimer value, and the prothrombin time-international normalize ratio (PT-INR). Adequate cut-off values for predicting the outcome were 3 as follows: DIC score, 3 points; D-dimer, 4.2 mg/L; and PT-INR, 1.08. D-dimer, which is a biomarker for thrombosis, is increased in various underlying diseases and predicts a poor outcome.