Microbiome of Tongue Coating Could Hold Clues Related to Heart Health

Results of a new study suggest the appearance and presence of certain microorganisms on a patient’s tongue could help inform clinicians about their cardiovascular health.

Presented as part of HFA Discoveries, a scientific platform of the European Society of Cardiology (ESC), findings of the study, which enrolled patients with chronic heart failure and compared them against healthy controls, found distinct differences in the appearance and microbiome data among patients with chronic heart failure.

"Our study found that the composition, quantity and dominant bacteria of the tongue coating differ between heart failure patients and healthy people," said lead investigator Tianhui Yuan, MD, of No. 1 Hospital of Guangzhou University of Chinese Medicine, in a statement.

With a multitude of studies suggesting a link between oral and cardiovascular health, investigators performed the current study in hopes of evaluating the composition of the tongue microbiome in patients with and without chronic heart failure. Designed as a prospective case-control study, investigators used sequencing technology tongue-coating samples collected from 60 chronic heart failure patients and 30 healthy controls.

Tongue-coating samples were collected in the morning before participants had brushed their teeth or eaten breakfast, using a stainless steel spoon. Investigators pointed out sequenced data were assessed using QIIME—additionally, the sequences obtained were distributed across 7 phyla, 27 genera, and 825 operational taxonomic units.

Of note, patients were excluded from the study if they had oral, tongue or dental diseases. Other exclusion criteria included suffering an upper respiratory tract infection in the past week, use of antibiotics or immunosuppressants in the last week, and being pregnant or in lactation.

In total, 42 chronic heart failure patients and 28 health controls were included in the investigators’ analysis. For the heart failure patients, median age was 79.5 years, disease duration ranged from 2-5 years, and all patients were classified as NYHA class 2-4. The median age of the control group was 25 years, with an overall range of 24-45 years.

Results of the analysis yielded 3 major findings. The first was patients with heart failure and the healthy controls shared unique types of microorganisms in their tongue coating that was not found in the opposing group.

The second finding included in the HFA Discoveries presentation dove further into the unique microbiome characteristics seen in the respective cohorts. Among heart failure patients, the microbiome was characterized predominantly by Neisseria, Capnocytophaga, Lactobacillus, Phocaeicola, Anaeroglobus, Butyrivibrio, Bacteroides, and Abiotrophia (P <.05, P <.001). Conversely, healthy controls were characterized by the presence of TM7 genus incertae sedis, Solobacterium, eubacterium, Murdochiella, Treponema 93, Anaerovorax, kingella, Peptococcus and Mogibacterium (P <.05, P <.001).

The final finding indicated analysis of the microbiome at the genus level suggested Capnocytophaga, TM7 genus incertae sedis, Peptostreptococcus, Solobacterium and Eubacterium could be used to identify chronic heart failure patients from the healthy controls (AUC, 83.7%; 95% CI, 74.1—93.3).

"More research is needed, but our results suggest that tongue microbes, which are easy to obtain, could assist with wide-scale screening, diagnosis, and long-term monitoring of heart failure,” Yuan added in the aforementioned statement. “The underlying mechanisms connecting microorganisms in the tongue coating with heart function deserve further study."

This study, “Tongue coating microbiome data distinguish patients with chronic heart failure from healthy controls,” was presented at HFA Discoveries.