Age-related diversity of the oral and gut microbiome and its correlation with systemic fatty acids and cytokine profiles in healthy subjects.

Oral microbiome composition differed across age groups, with distinct dominant genera in each group.

• In young adults (18-29 years), Fusobacterium and Haemophilus were notably abundant in the oral microbiome.
• In middle-aged adults (30-49 years), Haemophilus and Neisseria predominated in the oral microbiome.
• In older adults (≥50 years), Neisseria and Capnocytophaga were the most prevalent oral genera.
• Oral microbiome composition was evaluated using 16S rRNA sequencing of dental plaque samples.

Bacteroides was the most prevalent gut microbiome genus across all age groups, with consistent secondary genera also identified.

• Bacteroides was the dominant genus in the gut microbiome regardless of age group.
• Secondary prevalent gut genera included Faecalibacterium, Blautia, and Prevotella_9 across all age groups.
• Gut microbiome composition was evaluated using 16S rRNA sequencing of fecal samples.
• Participants spanned ages 18-76 years and were grouped into young, middle-aged, and older adult categories.

Circulating levels of specific free fatty acids were higher in young adults compared with older age groups.

• Decanoic acid, hexadecanoic acid, and octadecanoic acid were all higher in young adults (18-29 years) compared with middle-aged and older adults.
• Circulating free fatty acids (FFAs) were quantified by gas chromatography-mass spectrometry from blood samples.
• These differences in FFA profiles were observed in participants without diagnosed diseases.

The cytokine IP-10 was higher in young adults compared with the other age groups.

• IP-10 (also known as CXCL10) serum levels were elevated in young adults (18-29 years) relative to middle-aged and older adults.
• Serum cytokines were assessed using flow cytometry.
• IP-10 was identified among the cytokine profile differences across age groups.

This study is the first to characterize and correlate diversity of both the oral and gut microbiome with systemic free fatty acid and cytokine profiles in a cohort of healthy adults.

• Participants aged 18-76 years without diagnosed diseases were included.
• Blood, dental plaque, and fecal samples were collected from all participants.
• The authors state this represents a novel integration of microbial profiling with serum FFA and cytokine measurements.
• The study highlights the critical role of age in shaping microbiome composition and associated metabolites.

The study design included three age-based groups of healthy adults spanning a broad age range.

• Young adults were defined as 18-29 years, middle-aged adults as 30-49 years, and older adults as ≥50 years.
• The overall age range was 18-76 years.
• Inclusion criteria required absence of diagnosed diseases.
• Samples collected included blood, dental plaque, and fecal specimens for multi-omics analysis.