Assessing the Intestinal Microbiome in Transthyretin Amyloidosis With, Without Cardiac Involvement

Patients with transthyretin amyloidosis with or without cardiac involvement have a particular intestinal microbiome profile, according to a study being presented at the International Symposium on Amyloidosis 2024.

“The gastrointestinal tract may be affected by deposits in the parenchyma and due to changes in the autonomic nervous system. However, heart failure also may cause edema and hypoperfusion, leading to an increased gut permeability, and predisposes to intestinal microbiome disturbances,” the researchers noted.

In order to discern the intestinal microbiome composition, they assessed a total of 60 patients: 20 with cardiac involvement defined by a ventricular septum thickness >12 mm (G1), 20 without cardiac involvement (G2), and 20 controls. They then correlated echocardiographic parameters and cardiac biomarkers, such as troponin and BNP.

According to the results, in the 40 patients with or without cardiac involvement (G1 and G2), 85% had the hereditary form and 15% the wild form. The most prevalent mutation observed was Val142Ile, found in almost 53.0% of patients, followed by Val50Met (17.6%).

The differentially abundant bacteria observed in G1 and G2 were Streptococcus, Lachnospiraceae, and Sellimonas, while G3 presented a higher relative abundance of Methanosphaera. The researchers observed that Butyricoccaceae and Streptococcus were associated with higher levels of troponin I, while the genus Hungatella was associated with higher circulating levels of BNP. The results also showed that larger left atrial volumes correlated with Lachnospiraceae, and higher cardiac mass indexes were associated with Butyricoccaceae.

The researchers concluded that “patients with amyloidosis presented a particular intestinal microbiome profile when compared with the control group, and there was correlation with echocardiographic parameters and biomarkers of heart failure and necrosis.”