Role of brain-gut axis in pineal gland calcification

Introduction: Pineal gland is one of the endocrine organs that produce melatonin. Pineal gland sometimes has calcification, however, physiological significance of pineal gland calcification (PGC) remains to be fully elucidated. Accordingly, the degree of pineal gland calcification (DOC) in patients with dementia was known to be high. Recently, the relationship between gut microbiota and dementia or cerebrovascular diseases have attracted attention. However, the association among PGC, gut microbiota, and arteriosclerosis has not been investigated.Aims and Methods: The aim of this study is to examine the role of gut microbiota in the process of PGC. In this study, cognitive function tests were performed on elderly people aged 65 years or older, and PGC was evaluated from head CT scans and represented as the DOC score. We also underwent physiological function test and calculated cardio ankle vascular index. In addition, we collected stools and performed a metagenomic analysis (16s rRNA analysis) to examine the gut microbiota.Results: The taxonomy of gut microbiota at the genus level showed that the high abundance of the several butyrate-producing bacteria, including g__Coprococcus, g__Faecalibacterium, g__Roseburia, f__Ruminococcaceae;g__, f__Lachnospiraceae;Other are related with low DOC score. As for the physiological significance of the PGC, the low cardio ankle vascular index (CAVI) group had significant low DOC score, and the high mini mental state examination group had low CAVI as well.Conclusions: Our study indicated that the low PGC would be modulated by butyrate-producing bacteria and have relationship with arteriosclerosis and might give positive effect for maintaining cognitive function.