The aim of this study is to compare and analyze the structure and diversity of intestinal flora between gastric cancer patients and healthy people in the Qinghai-Tibet Plateau and to explore the characteristics of the intestinal flora composition in gastric cancer patients in the plateau area, and to determine the possible correlation between the intestinal flora and gastric cancer. Fresh feces from 22 cases of gastric cancer patients diagnosed in a tertiary hospital in Qinghai Province and 30 cases of healthy people during the same period were collected. The 52 subjects were undergone for 16S rDNA gene sequencing of intestinal bacteria to analyze and compare the diversity and compositional characteristics of intestinal flora. Analysis of the diversity of intestinal flora between the gastric cancer group and the healthy group was based on the Chao1 index of species richness, Shannon diversity index, and Simpson index. It showed that the gastric cancer group had no statistically difference from the healthy group (P > 0.05). In the Venn diagram, the number of OTU units shared by the gastric cancer group and the healthy group is 6997, and the number of unique OTU units in the healthy group is 2282, while the number of OTU units in the gastric cancer group is 896 and the difference is statistically significant (χ2 = 495.829), P < 0.000). Analysis of the composition and abundance distribution of intestinal flora showed that at the phylum level, there is no significant deference in abundance between the healthy group of Bacteroides and Firmicutes compared with the gastric cancer group (P > 0.05). However, there is a statistically significant difference in abundance between the healthy groups of Proteobacteria compared with the gastric cancer group (P < 0.05). At the genus level, the gastric cancer group of Prevotella_9 is significantly different from the healthy group (P < 0.05). Meanwhile, the gastric cancer group of Streptococcus and Lactobacillus are significantly different from the healthy group (P < 0.001). There are differences in the composition and abundance of intestinal flora between patients with gastric cancer and healthy people in plateau areas, suggesting that Proteobacteria, Prevotella_9, Streptococcus, and Lactobacillus have increased in the Qinghai-Tibet Plateau and becoming one of the factors related to the incidence of gastric cancer in the region.

Dietary nutrients can be converted by the gut microbiota into metabolites such as short-chain fatty acids, which may serve as disease-preventing agents in hypertension. Due to the limited population mobility and unique high-calorie dietary habits, the cohort of this study can serve as a representative cohort for elucidating the associations between the gut microbiota and hypertension under a high-calorie diet.

ObjectiveTo examine gut microbiotal diversity in the Han Chinese and Yugur populations of Sunan County, Gansu Province, living in the same environmental conditions, and to analyze possible causes of differences in diversity.MethodsWe selected 28 people, ages 18–45 years old, all of whom were third-generation pure Yugur or Han Chinese from Sunan County. Fresh fecal samples were collected, and total bacterial deoxyribonucleic acid (DNA) was extracted. We performed 16S ribosomal ribonucleic acid (16S rRNA) high-throughput sequencing (HTS) and bioinformatics to study the relationships among between gut microbiota structure, genetics, and dietary habits in Yugur and Han Chinese subjects.ResultsWe found 350 differential operational taxonomic units (OTUs) in Han Chinese and Yugur gut microbiota, proving that gut microbiota differed between the two populations. That were less abundant among Yugurs than Han Chinese were Prevotella_9 and Alloprevotella. That were more abundant among Yugurs than Han Chinese were Anaerostipes and Christensenellaceae_R-7_group. And they were significantly associated with a high-calorie diet In addition. we found differences in predicted gut microbiota structural functions (The main functions were metabolic and genetic information) between the two populations.ConclusionYugur subjects demonstrated differences in gut microbiotal structure from Han Chinese subjects, and this difference influenced by dietary and may be influenced by genetic influences. This finding will provide a fundamental basis for further study of the relationships among gut microbiota, dietary factors, and disease in Sunan County.

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Gut microbial dysbiosis has been associated with hypertension. An extremely high incidence of essential hypertension was found in the Han and the Yugur who resided in Sunan county in East Asia's nomadic steppes with little population movement. In attempt to investigate the gut microbial role in hypertension, we recruited a total of 1, 242 Yugur and Han people, who had resided in Sunan County for more than 15 years and accounted for 3% of the local population. The epidemiological survey of 1,089 individuals indicated their nearly 1.8 times higher prevalence of hypertension (38.2–43.3%) than the average in China (23.2%), under a special high-calorie diet based on wheat, cattle, mutton, and animal offal. The 16S rRNA gene sequencing on the fecal samples of 153 individuals revealed that certain Lachnospiraceae genera were negatively correlated with high-density lipoprotein cholesterol (HDL-C, P = 5.46 × 10−6), systolic blood pressure (SBP, P = 7.22 × 10−3), diastolic blood pressure (DBP, P = 1.8 × 10−3). HDL-C was positively correlated with SBP (P = 0.023). We further observed that serum butyrate content was lower in both Han (P = 1.99 × 10−3) and Yugur people (P = 0.031) with hypertension than those without hypertension. This study gives a novel insight into the role of gut microbial dysbiosis in hypertension modulation under a high-calorie diet, where the notable depletion of Lachnospiraceae genera might lead to less production of butyrate, contributing to the lower level of HDL-C, and elevating blood pressure in hypertension.