Frequency of Tongue Cleaning Impacts the Human Tongue Microbiome Composition and Enterosalivary Circulation of Nitrate

ECU Author/Contributor (non-ECU co-authors, if there are any, appear on document)

Gena D.,Angelov,Nikola,Weltman,Robin,Wang,Bing-Yan,Eswa Tribble (Creator)

Institution

East Carolina University (ECU )

Web Site: http://www.ecu.edu/lib/

Abstract: The oral microbiome has the potential to provide an important symbiotic function inhuman blood pressure physiology by contributing to the generation of nitric oxide(NO), an essential cardiovascular signaling molecule. NO is produced by the humanbody via conversion of arginine to NO by endogenous nitric oxide synthase (eNOS)but eNOS activity varies by subject. Oral microbial communities are proposed tosupplement host NO production by reducing dietary nitrate to nitrite via bacterialnitrate reductases. Unreduced dietary nitrate is delivered to the oral cavity in saliva, aphysiological process termed the enterosalivary circulation of nitrate. Previous studiesdemonstrated that disruption of enterosalivary circulation via use of oral antisepticsresulted in increases in systolic blood pressure. These previous studies did notinclude detailed information on the oral health of enrolled subjects. Using 16S rRNAgene sequencing and analysis, we determined whether introduction of chlorhexidineantiseptic mouthwash for 1 week was associated with changes in tongue bacterialcommunities and resting systolic blood pressure in healthy normotensive individualswith documented oral hygiene behaviors and free of oral disease. Tongue cleaningfrequency was a predictor of chlorhexidine-induced changes in systolic blood pressureand tongue microbiome composition. Twice-daily chlorhexidine usage was associatedwith a significant increase in systolic blood pressure after 1 week of use and recoveryfrom use resulted in an enrichment in nitrate-reducing bacteria on the tongue. Individualswith relatively high levels of bacterial nitrite reductases had lower resting systolic bloodpressure. These results further support the concept of a symbiotic oral microbiomecontributing to human health via the enterosalivary nitrate-nitrite-NO pathway. These datasuggest that management of the tongue microbiome by regular cleaning together withadequate dietary intake of nitrate provide an opportunity for the improvement of restingsystolic blood pressure.

Additional Information

Publication

Other

Language: English

Date: 2019

Keywords

oral microbiome, microbiome, microbial ecology, host-microbial symbiosis, nitrate, nitric oxide

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