Gut microbiota-dependent trimethylamine N-oxide pathway associated with cardiovascular risk in children with early-stage chronic kidney disease

Despite cardiovascular disease (CVD) being the leading cause of morbidity and mortality in chronic kidney disease (CKD), less attention has been paid to subclinical CVD in children and adolescents with early CKD stages. Gut microbiota and their metabolite, trimethylamine N-oxide (TMAO), have been linked to CVD. Ambulatory blood-pressure monitoring (ABPM) and arterial-stiffness assessment allow for early detection of subclinical CVD. We therefore investigated whether gut microbial composition and TMAO metabolic pathway are correlated with blood-pressure (BP) load and vascular abnormalities in children with early-stage CKD. We enrolled 86 children with G1–G3 CKD stages. Approximately two-thirds of CKD children had BP abnormalities on ABPM. Children with CKD stage G2–G3 had a higher uric acid level (6.6 vs. 4.8 mg/dL, p < 0.05) and pulse-wave velocity (4.1 vs. 3.8 m/s, p < 0.05), but lower TMAO urinary level (209 vs. 344 ng/mg creatinine, p < 0.05) than those with stage G1. Urinary TMAO level was correlated with the abundances of genera Bifidobacterium (r = 0.307, p = 0.004) and Lactobacillus (r = 0.428, p < 0.001). CKD children with abnormal ABPM profile had a lower abundance of the Prevotella genus than those with normal ABPM (p < 0.05). Our results highlight the link between gut microbiota, microbial metabolite TMAO, BP load, and arterial-stiffness indices in children with early-stage CKD. Early assessments of these surrogate markers should aid in decreasing cardiovascular risk in childhood CKD.