Arginine Improves pH Homeostasis via Metabolism and Microbiome Modulation

Area of Science:

• Oral microbiology
• Dental research
• Microbial ecology

Background:

• Dental caries result from oral microbial dysbiosis, where acid-producing bacteria cause demineralization.
• Alkali production via arginine metabolism is crucial for maintaining oral plaque pH homeostasis.
• Arginine in dentifrices shows potential for caries protection.

Purpose of the Study:

• To investigate the mechanistic and ecological impact of arginine on the oral microbiome.
• To analyze arginine's role in regulating oral pH dynamics.
• To assess arginine's effect on oral biofilm structure and function.

Main Methods:

• Utilized an in vitro multispecies oral biofilm model with pooled human saliva.
• Investigated arginine uptake and metabolite production within biofilms.
• Assessed pH dynamics after sucrose challenge in arginine-pretreated biofilms.
• Analyzed microbial community structure via 16S sequencing and metabolomics.

Main Results:

• Arginine treatment prevented sustained pH drops caused by sucrose, promoting pH recovery.
• Detected active arginine uptake and metabolism into citrulline, ornithine, and putrescine.
• Observed a shift in microbial community structure and increased species diversity in arginine-treated biofilms.

Conclusions:

• Arginine actively modulates the oral microbiome's metabolic activity and ecological balance.
• Arginine treatment enhances oral pH homeostasis, offering a potential strategy against dental caries.
• The study demonstrates arginine's capacity to remodel the oral microbial community for improved oral health.