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Gut microbiota composition influences outcomes of skeletal muscle nutritional intervention via blended protein supplementation in posttransplant patients with hematological malignancies.
Ren, G, Zhang, J, Li, M, Tang, Z, Yang, Z, Cheng, G, Wang, J
Clinical nutrition (Edinburgh, Scotland). 2021;(1):94-102
Abstract
BACKGROUND Skeletal muscle atrophy is an important and independent predictor of survival after hematopoietic stem cell transplantation (HSCT). Our previous study found that soy-whey blended protein (SWP) can improve muscle mass in acute leukemia patients. OBJECTIVE We aimed to explore potential factors that influence muscle outcomes after nutritional intervention. METHODS In this case-control study, 13 patients who received HSCT and failed to improve muscle function within half a year were included. After two months of SWP intervention, the subjects were divided into two groups (MSI: muscle status improved; MNI: muscle status not improved). 16S rDNA sequencing, principal coordinate analysis (PCoA) and the PICRUSt algorithm were used to analyze the composition, structure and function of the intestinal microbiota between the groups. This study was registered in the Chinese Clinical Trial Registry (ChiCTR 1800017765). RESULTS SWP significantly improved muscle status (muscle area: from 330.4 mm2 to 384.8 mm2, p = 0.02; muscle strength: from 19.2 kg to 21.3 kg, p = 0.04). However, there were a small number of subjects whose muscle status was not effectively improved. After SWP intervention, the diversity (Shannon: from 1.7 to 3.8, p = 0.01; Simpson: from 0.6 to 0.8, p = 0.015) of the intestinal microbiota in the MSI group increased significantly, whereas that in the MNI group did not. Principal component analysis (PCA) revealed separate groupings of the microbiota of the Baseline-MSI and Endpoint-MSI time points in the MSI group. Opposite patterns of microbial abundance change were found between the MSI group (75% of changed genera were increased) and the MNI group (80% of changed genera were decreased). Three bacterial taxa (negative correlation: Streptococcus; positive correlations: Ruminococcus and Veillonella) were significantly related to muscle improvement outcomes. Both pentose phosphate (p = 0.048) and amino acid biosynthesis (p = 0.039), which are related to muscle metabolism, were found to be significantly changed in the MSI group through PICRUSt algorithm prediction. CONCLUSIONS Our results suggest that the intestinal microbiota plays important roles in the regulation of muscle metabolism.
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Unconjugated and secondary bile acid profiles in response to higher-fat, lower-carbohydrate diet and associated with related gut microbiota: A 6-month randomized controlled-feeding trial.
Wan, Y, Yuan, J, Li, J, Li, H, Zhang, J, Tang, J, Ni, Y, Huang, T, Wang, F, Zhao, F, et al
Clinical nutrition (Edinburgh, Scotland). 2020;(2):395-404
Abstract
BACKGROUND & AIMS Observational studies have shown that diets high in fat and low in dietary fiber, might have an unfavorable impact on bile acid (BA) profiles, which might further affect host cardiometabolic health. In the current study, we aimed to evaluate the effects of dietary fat content on BA profiles and associated gut microbiota, and their correlates with cardiometabolic risk factors. METHODS In a randomized controlled-feeding trial, healthy young adults were assigned to one of the three diets: a lower-fat diet (fat 20%, carbohydrate 66% and protein 14%), a moderate-fat diet (fat 30%, carbohydrate 56% and protein 14%) and a higher-fat diet (fat 40%, carbohydrate 46% and protein 14%) for 6 months. All the foods were provided during the entire intervention period. The BA profiles, associated gut microbiota and markers of cardiometabolic risk factors were determined before and after intervention. RESULTS The higher-fat diet resulted in an elevated concentration of total BAs (p < 0.001), and unconjugated BAs (p = 0.03) compared with lower-fat diet. Secondary BAs, such as deoxycholic acid (DCA), taurodeoxycholic acid (TDCA), 12ketolithocholic acid (12keto-LCA), 3β-DCA and taurolithocholic acid (TLCA) (p < 0.05 after FDR correction) were significantly increased in the higher-fat diet group after the 6-month intervention. Consistently, the abundances of gut bacteria (Bacteroides, Clostridium, Bifidobacterium and Lactobacillus) which affect bile salt hydrolase gene expression were significantly increased after higher-fat consumption. The change of DCA was positively associated with the relative abundance of Bacteroides (r = 0.31, p = 0.08 after FDR correction). In addition, the changes of fecal concentrations of DCA and 12keto-LCA were positively associated with serum total cholesterol (r > 0.3, p = 0.02 and p = 0.008 after FDR correction, respectively). In line with these findings, serum fibroblast growth factor 19 (FGF19) was marginally significantly elevated in the higher-fat group after intervention (p = 0.05). CONCLUSIONS The higher-fat diet resulted in an alteration of BAs, especially unconjugated BAs and secondary BAs, most likely through actions of gut microbiota. These alterations might confer potentially unfavorable impacts on colonic and host cardiometabolic health in healthy young adults. Clinical trial registry number: NCT02355795 listed on NIH website: ClinicalTrials.gov.
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Alteration of the esophageal microbiota in Barrett's esophagus and esophageal adenocarcinoma.
Lv, J, Guo, L, Liu, JJ, Zhao, HP, Zhang, J, Wang, JH
World journal of gastroenterology. 2019;(18):2149-2161
Abstract
The incidence of esophageal adenocarcinoma (EAC) has increased in recent decades, and its 5-year survival rate is less than 20%. As a well-established precursor, patients with Barrett's esophagus (BE) have a persistent risk of progression to EAC. Many researchers have already identified some factors that may contribute to the development of BE and EAC, and the identified risks include gastroesophageal reflux (GER), male sex, older age, central obesity, tobacco smoking, Helicobacter pylori (H. pylori) eradication, and the administration of proton pump inhibitors (PPIs) and antibiotics. The human gut harbors trillions of microorganisms, the majority of which are bacteria. These microorganisms benefit the human host in many ways, such as helping in digestion, assisting in the synthesis of certain vitamins, promoting the development of the gastrointestinal immune system, regulating metabolism and preventing invasion by specific pathogens. In contrast, microbial dysbiosis may play important roles in various diseases, such as inflammation and cancers. The composition of the microbiota located in the normal esophagus is relatively conserved without distinct microbial preferences in the upper, middle and lower esophagus. Six major phyla constitute the esophageal microbiota, including Firmicutes, Bacteroides, Actinobacteria, Proteobacteria, Fusobacteria and TM7, similar to the oral microbiota. Streptococcus dominates the esophageal microbiota. However, the microbiota varies in different esophageal diseases compared to that in the healthy esophagus. The type I microbiota, which is primarily composed of gram-positive bacteria, is closely associated with the normal esophagus, while type II microbiota has enriched gram-negative bacteria and is mainly associated with the abnormal esophagus. These increased gram-negative anaerobes/microaerophiles include Veillonella, Prevotella, Haemophilus, Neisseria, Granulicatella and Fusobacterium, many of which are associated with BE. The microbial diversity in the esophagus is decreased in EAC patients, and Lactobacillus fermentum is enriched compared to that in controls and BE patients. Furthermore, the microbiota may be associated with BE and EAC by interacting with their risk factors, including central obesity, GER, H. pylori, administration of PPIs and antibiotics. Therefore, a large gap in research must be bridged to elucidate the associations among these factors. Some studies have already proposed several potential mechanisms by which the microbiota participates in human carcinogenesis by complicated interactions with the human host immune system and signaling pathways. The activation of the LPS-TLR4-NF-κB pathway may contribute to inflammation and malignant transformation. This exciting field of gastrointestinal microbiota allows us to unravel the mystery of carcinogenesis from another perspective. Further studies are needed to explore whether the microbiota changes before or after disease onset, to improve our understanding of the pathogenesis, and to find novel targets for prevention, diagnosis and therapy, which could offer more cost-effective and relatively safe choices.
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Effects of dietary fat on gut microbiota and faecal metabolites, and their relationship with cardiometabolic risk factors: a 6-month randomised controlled-feeding trial.
Wan, Y, Wang, F, Yuan, J, Li, J, Jiang, D, Zhang, J, Li, H, Wang, R, Tang, J, Huang, T, et al
Gut. 2019;(8):1417-1429
Abstract
OBJECTIVE To investigate whether diets differing in fat content alter the gut microbiota and faecal metabolomic profiles, and to determine their relationship with cardiometabolic risk factors in healthy adults whose diet is in a transition from a traditional low-fat diet to a diet high in fat and reduced in carbohydrate. METHODS In a 6-month randomised controlled-feeding trial, 217 healthy young adults (aged 18-35 years; body mass index <28 kg/m2; 52% women) who completed the whole trial were included. All the foods were provided during the intervention period. The three isocaloric diets were: a lower-fat diet (fat 20% energy), a moderate-fat diet (fat 30% energy) and a higher-fat diet (fat 40% energy). The effects of the dietary interventions on the gut microbiota, faecal metabolomics and plasma inflammatory factors were investigated. RESULTS The lower-fat diet was associated with increased α-diversity assessed by the Shannon index (p=0.03), increased abundance of Blautia (p=0.007) and Faecalibacterium (p=0.04), whereas the higher-fat diet was associated with increased Alistipes (p=0.04), Bacteroides (p<0.001) and decreased Faecalibacterium (p=0.04). The concentration of total short-chain fatty acids was significantly decreased in the higher-fat diet group in comparison with the other groups (p<0.001). The cometabolites p-cresol and indole, known to be associated with host metabolic disorders, were decreased in the lower-fat diet group. In addition, the higher-fat diet was associated with faecal enrichment in arachidonic acid and the lipopolysaccharide biosynthesis pathway as well as elevated plasma proinflammatory factors after the intervention. CONCLUSION Higher-fat consumption by healthy young adults whose diet is in a state of nutrition transition appeared to be associated with unfavourable changes in gut microbiota, faecal metabolomic profiles and plasma proinflammatory factors, which might confer adverse consequences for long-term health outcomes. TRIAL REGISTRATION NUMBER NCT02355795; Results.