HEART RATE VARIABILITY AND GUT MICROBIOTA INTERACTION IN DEPRESSION VULNERABILITY: A NON-CLINICAL EXPLORATORY INVESTIGATION<EM> </EM>

The aim of the study is to explore whether there is an interaction between heart rate variability (HRV), as a surrogate measure of cardiac vagal activity, gut microbiota features and stress-related psychological symptoms in a non-clinical sample. A secondary aim is to explore putative sex and age differences.
A non-clinical sample of healthy adults was examined within the framework of the “Parma Microbiota Project”. Participants provided stool samples for the characterization of gut microbiota composition, completed psychometric questionnaires - state and trait anxiety inventory (STAI-S and STAI-T), perceived stress scale (PSS) and center of epidemiologic studies depression scale (CES-D) - and underwent resting state HRV assessment. The sample was divided in low-HRV and high-HRV groups, using the median HRV value of the total sample.
Preliminary results show that participants in the low-HRV group exhibit higher depressive symptoms, in terms of CES-D scores, compared to those in the high-HRV group, as well as a greater microbial alpha diversity, in terms of species richness. Additionally, the low-HRV group exhibited a lower relative abundance of Faecalibacterium prausnitzii, compared to the high-HRV group. The relative abundance of Faecalibacterium prausnitzii was also correlated with HRV values and CES-D scores.
These preliminary findings warrant future investigation into the role of the vagus nerve in the interaction between the gut microbiota characteristics and depressive vulnerability in healthy populations, and support current evidence that some microbial species, such as Faecalibacterium prausnitzii, may be implicated in the pathophysiology of depression.