Assessing the Oral Microbiome in Blood Pressure Regulation: Measuring the Impact of Chlorhexidine on Nitrate Reducing Communities
Objectives: Nitric oxide (NO) is a critical signaling molecule in human cardiovascular physiology. In our study, we recruited a cohort of orally-healthy subjects to determine if a correlation exists between initial/final blood pressure readings, oral flora composition, and chlorhexidine use over 14 days.
Methods: Subject tongue samples were collected and initial blood pressure data was recorded. After one week of chlorhexidine use, we sampled subject tongue bacteria and recorded blood pressure data. Additional bacterial and BP data were collected after 3 and 7 days recovery from chlorhexidine use. Significant changes in BP were detected with ANOVA and post-hoc tests. Bacterial community content was assessed with 16s rDNA sequencing and significant changes detected with non-parametric ANOVA. Community metabolic potential was mapped using PATRIC pathway comparison software. This study is approved by the Committee for the Protection of Human Subjects at the University of Texas Health Science Center at Houston (HSC-DB-14-0078).
Results: 27 subjects were enrolled: significant changes in blood pressure were detected after 3 and 7 days recovery from chlorhexidine. Community diversity is significantly disrupted by chlorhexidine use, and during recovery an increase in nitrate reducing bacteria correlated with a significant decrease in blood pressure.
Conclusions: Rinsing with Chlorhexidine for 7 days can affect blood pressure regulation and lead to substantial increase or decrease in blood pressure. These changes in basal systemic blood pressure may be due to the nitrate reducing oral microbial communities that are present at any given time. Moreover, the increase or decrease of blood pressure may depend on the on the baseline community composition and/or subsequent alteration of the ecology of these oral microbial communities.