A recent study, led by Dr. Claire Steves, a clinical research fellow from the Department of Twin Research & Genetic Epidemiology, King’s College London, identified several associations between host frailty and gut microbiota diversity, which might offer potential targets for intervention to strengthen healthy ageing.
Frailty is a clinically recognizable state of increased vulnerability resulting from ageing-associated decline in reserve and function across multiple physiologic systems. As compared to chronological age, it is a more useful predictor of poor health outcomes including hospitalization, dependency and mortality. It has been suggested that gut immune response and microbiota composition are impaired in the elderly, although a causal relationship cannot yet be assumed between aging and gut microbiota changes. Previous research from the same group confirmed that frailty was associated with gut microbiome composition in elderly and care-dependent individuals.
Jackson and colleagues used a clinical index to quantify frailty in 728 female twins from a community-dwelling cohort (TwinsUK cohort) aged 42-86 years, in addition to characterizing microbial 16S ribosomal RNA signatures from faecal samples. Possible confounding factors including diet and environmental factors were taken into account. Results were also compared with those from the Eldermet cohort, an Ireland-based cohort of 280 elderly individuals aged 64-102 years.
The researchers found a prominent negative correlation between host frailty and gut microbial diversity, involving specific taxonomic associations. Frailty was associated with species and genus abundance. Species more abundant with frailty included Eubacterium dolichum and Eggerthella lenta. Also, Faecalibacterium prausnitzii was less abundant in frailer individuals. Different operational taxonomic unit (OTU) abundance was demonstrated between twin pairs discordant for frailty. The Dorea OTU was significantly increased in frailer twins, whereas F. prausnitzii and Lachnospiraceae OTUs were significantly lowered. However, whether these relationships are causal or consequential is unknown. Finally, a number of OTU associations observed within TwinsUK were replicated in the Eldermet cohort.
To sum up, significant associations between frailty and the gut microbiota were found in a large cohort of female twins, which might ultimately be used for diagnostic surveillance or to prevent frailty during ageing.
Jackson MA, Jeffery IB, Beaumont M, et al. Signatures of early frailty in the gut microbiota. Genome Medicine. 2016;8:8. doi:10.1186/s13073-016-0262-7.