Trimethylamine N-Oxide (TMAO) Plasma Levels in Patients with Different Stages of Chronic Kidney Disease

Background: In patients with chronic kidney disease (CKD), trimethylamine n-oxide (TMAO) accumulation exacerbates inflammation and contributes to oxidative stress. These complications are putatively linked to the development of cardiovascular diseases. Despite the known associations, the variation in TMAO plasma levels across different CKD stages and dialysis modalities remains underexplored. This study aimed to quantify TMAO plasma levels in different CKD stages and dialysis treatments. Methods: This cross-sectional study assessed TMAO plasma levels in non-dialysis CKD patients (ND), patients undergoing hemodialysis (HD), and peritoneal dialysis (PD). TMAO plasma levels were assessed by liquid chromatography coupled to triple mass spectrometry quadrupole. Results: In total, 15 ND patients [stages 3–5, glomerular filtration rate 41.4 mL/min/1.73 m2, 64 (IQR = 12.5) years, BMI 25.2 kg/m2, eight women]; 14 PD patients [57.5 (IQR = 8.5) years, BMI of 27.8 kg/m2, nine women]; and 34 HD patients [43.5 (IQR = 45.5) years, BMI of 24.4 kg/m2, nineteen women] were analyzed. ND patients had lower TMAO levels when compared to the HD (p < 0.0001) and PD patients (p = 0.001). There was no difference in TMAO levels between patients undergoing dialysis (p < 0.59). There was a negative correlation between TMAO and HDL plasma levels [rho = −0.380 (p < 0.004)], calcium [rho = −0.321 (p < 0.016)], and albumin [rho = −0.416 (p < 0.001)]. In addition, a positive correlation between TMAO and urea levels was observed [rho = 0.717 (p < 0.001)]. Conclusions: CKD stages impact TMAO levels since patients on non-dialysis treatment had lower levels than patients on HD and PD.