Gut microbiota in older cancer survivors linked to cognitive function

Key takeaways:

• Distinct microbiome signatures exist in the gut of older cancer survivors, impacting cognition.
• The relatively highest concentrations of bacteroides were found in those with cognitive impairment.

ORLANDO, Fla. — An analysis of the gut microbiome among individuals who survived cancer revealed a significant association between the gut-brain axis, particularly in gut microbiota, metabolism and cognitive function, according to a poster.

“Gut-brain is a newly studied axis that allows us to look at the gut and consider it almost as a second brain,” Jayden A. Haggler, an undergraduate research assistant at the University of South Florida Center for Microbiome Research, told Healio at the American Neurological Association annual meeting. “The opportunity to change cognitive outcomes by using an organ that is distant from the brain is quite interesting.”

Haggler and colleagues sought to increase the understanding of specific microbiome signatures among cancer survivors and how they may influence cognitive status, which directly impact the aging process.

Their research culled data from the Microbiome in aging gut and brain (MiaGB) Consortium, a multisite study in Florida that focuses on microbiome health of older adults who are either cognitively healthy or diagnosed with Alzheimer’s disease dementia or mild cognitive impairment.

The study included 150 individuals from MiaGB, both with a cancer diagnosis (n = 49) and without (n = 101), who were asked to contribute a stool sample as well as provide genome sequencing, submit to the Montreal Cognitive Assessment (MoCA) and undergo a metabolic pathway analysis via the HuMAnN 3.0.

Upon completion of the battery, enrollees were subdivided into four categories: non-cancer without cognitive impairment (n = 64), non-cancer with cognitive impairment (n = 37); cancer without cognitive impairment (n = 29) and those with cancer and cognitive impairment (n = 20).

The researchers reported finding significant correlations between gut microbiota and metabolic pathways with respect to cognitive function in participants who survived cancer.

A high level of firmicutes were found in the gut of participants, regardless of cancer or cognitive status, relative to all other major bacterial phyla, with Bacteroidetes and actinobacteria found in the next greatest concentrations in the study population.

Among major bacterial genera, the highest concentrations found were bacteroides and blautia, again, regardless of disease or cognitive status. However, participants with cognitive impairment had the relatively highest concentrations of blautia, according to the researchers.

Haggler and colleagues acknowledged study limitations such as a relatively small sample size and lack of investigation into the biologic impact of cancer treatments. They suggest future research should include age-matching analyses to further refine the nature of cognitive impairment.

“We were able to point out certain [gut microbiome] species that are up regulated or down regulated within cognitive status,” Haggler said. “An individual could have cognitive impairment and that allows us to intervene with some therapeutic measures and potentially change their cognitive status.”