Trimethylamine-N-oxide (TMAO) Is Elevated in the Acute Phase after Ischemic Stroke and Decreases Within the First Days.

OBJECTIVES: Trimethylamine N-oxide (TMAO) is a biomarker of the gut microbiome and correlates with the risk of cardiovascular diseases. However, conflicting data exist on the specific role of TMAO in ischemic stroke patients. We aimed at analyzing the time course of TMAO levels in stroke patients compared to controls. METHODS: In this prospective, case-control-study, patients suffering from ischemic stroke (onset <24 hours) and control patients with less than two cardiovascular risk factors were enrolled. Plasma TMAO levels were analyzed on admission, after 48 hours and after three months. Primary endpoint was the difference in TMAO levels on admission between stroke patients and controls. RESULTS: 196 patients with ischemic stroke and 100 controls were included from February 2018 to April 2019. Plasma TMAO levels on admission were significantly higher in stroke patients than in controls (median value 4.09 [2.87; 6.49] vs. 3.16 [2.08; 5.16] micromol/l, p=0.001). There was a significant decrease in TMAO levels in stroke patients after 48 hours (median at 48 hours 3.49 micromol/l [2.30; 5.39], p=0.027). TMAO levels increased again three months after stroke (median 4.23 micromol/l [2.92; 8.13], p=0.047). In controls, TMAO levels did not change between admission and after 48 hours (median at 48 hours 3.14 micromol/l [1.63; 4.61], p=0.11). An inverse correlation between TMAO values and kidney function was found (Spearman Rho -0.334, p<0.001). CONCLUSIONS: Our study emphasizes the importance of the time course of TMAO levels after ischemic stroke. Future studies should define the time point of TMAO analysis, preferably in the acute phase (<24h).