Population-based metagenomics analysis reveals altered gut microbiome in sarcopenia: data from the Xiangya Sarcopenia Study

Abstract

Background: Several studies have examined gut microbiota and sarcopenia using 16S ribosomal RNA amplicon sequencing; however, this technique may not be able to identify altered specific species and functional capacities of the microbes. We performed shotgun metagenomic sequencing to compare the gut microbiome composition and function between individuals with and without sarcopenia.

Methods: Participants were from a community-based observational study conducted among the residents of rural areas in China. Appendicular skeletal muscle mass was assessed using direct segmental multi-frequency bioelectrical impedance and grip strength using a Jamar Hydraulic Hand dynamometer. Physical performance was evaluated using the Short Physical Performance Battery, 5-time chair stand test and gait speed with the 6 m walk test. Sarcopenia and its severity were diagnosed according to the Asian Working Group for Sarcopenia 2019 algorithm. The gut microbiome was profiled by shotgun metagenomic sequencing to determine the microbial composition and function. A gut microbiota-based model for classification of sarcopenia was constructed using the random forest model, and its performance was assessed using the area under receiver-operating characteristic curve (AUC).

Results: The study sample included 1417 participants (women: 58.9%; mean age: 63.3 years; sarcopenia prevalence: 10.0%). β-diversity indicated by Bray-Curtis distance (genetic level: P = 0.004; taxonomic level of species: P = 0.020), but not α-diversity indicated by Shannon index (genetic level: P = 0.962; taxonomic level of species: P = 0.922), was significantly associated with prevalent sarcopenia. After adjusting for potential confounders, participants with sarcopenia had higher relative abundance of Desulfovibrio piger (P = 0.003, Q = 0.090), Clostridium symbiosum (P < 0.001, Q = 0.035), Hungatella effluvii (P = 0.003, Q = 0.090), Bacteroides fluxus (P = 0.002, Q = 0.089), Absiella innocuum (P = 0.002, Q = 0.072), Coprobacter secundus (P = 0.002, Q = 0.085) and Clostridium citroniae (P = 0.001, Q = 0.060) than those without sarcopenia. The relative abundance of six species (Desulfovibrio piger, Clostridium symbiosum, Hungatella effluvii, Bacteroides fluxus, Absiella innocuum, and Clostridium citroniae) was also positively associated with sarcopenia severity. A differential species-based model was constructed to separate participants with sarcopenia from controls. The value of the AUC was 0.852, suggesting that model has a decent discriminative performance. Desulfovibrio piger ranked the highest in this model. Functional annotation analysis revealed that the phenylalanine, tyrosine, and tryptophan biosynthesis were depleted (P = 0.006, Q = 0.071), while alpha-Linolenic acid metabolism (P = 0.008, Q = 0.094), furfural degradation (P = 0.001, Q = 0.029) and staurosporine biosynthesis (P = 0.006, Q = 0.072) were enriched in participants with sarcopenia. Desulfovibrio piger was significantly associated with staurosporine biosynthesis (P < 0.001).

Conclusions: This large population-based observational study provided empirical evidence that alterations in the gut microbiome composition and function were observed among individuals with sarcopenia.

Keywords: Gut microbiome; Metagenomics; Population-based study; Sarcopenia.

Figure 1

Selection process of the included subjects in the study.

Figure 2

Comparison of gut microbial diversity and composition of participants with and without sarcopenia. Box plot comparing the participants with and without sarcopenia of α‐diversity measured by the Shannon index at the genetic level (A). The horizontal bar within each box represents the median. The bottom and top of each box represent the 25th and 75th percentiles, respectively. Line plot comparing participants with and without sarcopenia of α‐diversity indicated by the Shannon index at the taxonomic levels from phylum to species (B). Each plot represents the mean of the Shannon index. PCoA plot comparing participants with and without sarcopenia of β‐diversity measured by the Bray‐Curtis distance at the genetic level (C). Line plot comparing participants with and without sarcopenia of β‐diversity indicated by the Bray–Curtis distance at the taxonomic levels from phylum to species (D). Each plot represents the mean of the Shannon index. PCoA, principal coordinates analysis; PERMANOVA, permutation multivariate analysis of variance.

Figure 3

Microbiota genus and species alterations in sarcopenia. Relative abundance of the differential gut microbiota between participants with and without sarcopenia at the genus (A) and species (B) levels. The horizontal bar within each box represents the median. The bottom and top of each box represent the 25th and 75th percentiles, respectively. Linear associations between the relative abundance of bacterial species and sarcopenia severity (C). The trend line is fitted using a linear model.

Figure 4

Random forest model based on differentially abundant species classifying participants with sarcopenia and controls. Receiver‐operating characteristic curve of the test set. The diagonal line in the graph represents an AUC of 0.5 (A). Species are ranked in descending order of importance to the model's accuracy based on mean decrease accuracy (B) and Gini index (C). AUC, area under receiver‐operating characteristic curve.

Figure 5

Functional characterization alterations of gut microbiota in sarcopenia. Difference in the relative abundances of predicted functions based on KEGG pathways and modules between individuals with and without sarcopenia (A). The vertical bar within each box represents the median. The bottom and top of each box represent the 25th and 75th percentiles, respectively. The association between bacterial species and KEGG pathways and modules (B). Red indicates a positive association; blue indicates a negative association. KEGG, Kyoto Encyclopaedia of Genes and Genomes.