A group of Japanese scientists from Hirosaki University Graduate School of Medicine explored the links between gut microbiome and overactive bladder (OAB) with daily urinary urgency (at least once per week). This cross-sectional study surveyed 1,113 individuals taking part in the Iwaki Health Promotion Project in Japan.
The study found that participants with OAB had a higher degree of depressive symptoms compared to those in the non-OAB group. Moreover, the gut microbiome of individuals with OAB showed a lower bacterial diversity (i.e. gut dysbiosis), particularly having a significantly lower in relative abundance of genus Bifidobacterium (2.41% vs 4.23%) compared to the non-OAB group. Interestingly, the results showed that in the OAB group, genus Faecalibacterium was overrepresented (9.25% vs 6.26%). Faecalibacterium species are short chain fatty acid (SCFA) producer. The authors explained that excessive SCFA (i.e. butyric acid) has been shown to increase brain derived neurotrophic factor (BDNF) in an animal model, and that urinary BDNF levels are reported to be high among OAB individuals, which may result in enhanced bladder detrusor activity.
Okamoto T. et al. (2020) Altered gut microbiome associated with overactive bladder and daily urinary urgency. World J Urol. Online ahead of print.