Supplementary Material
cirrhosis, end-stage liver disease
CIRRHOSIS
To explore the potential mechanisms underlying the effects of a probiotic in cirrhotic patients, we analyzed the blood metabolome using proton nuclear magnetic resonance (In a previous double-blinded, placebo-controlled, randomized clinical trial, we observed that a multistrain probiotic improved cognitive function and risk of falls, reinforced the intestinal barrier, and modulated the proinflammatory state in patients with cirrhosis.We analyzed serum metabolome in samples from 32 outpatients with cirrhosis included in the study mentioned above.Patients had a mean age of 64.5 years, 65.6% were women, the etiology of cirrhosis was alcohol in 50%, the mean model for end-stage liver disease (MELD) score was 9.3, 81.2% had previous decompensations, 84.3% had previous falls, and 28.1% presented a PHES <−4. There were no statistical differences between the 2 groups at baseline.The untargeted observation of the serum metabolome by (A) Volcano plots showing the change between baseline and 12 weeks in all metabolites identified in the probiotic group and in the placebo group. (B) Changes in glutamine/glutamate ratio in patients treated with the probiotic and patients treated with placebo. Results are expressed as mean (SD). Abbreviation: FDR, false discovery rate.Regarding metagenomic results, when we focused on the serum glutamine/glutamate ratio, analyzing all the 30 samples at the genus level, we observed this ratio was associated with an abundance of The increase in the serum glutamine/glutamate ratio observed in the present study in probiotic-treated patients could reflect a higher capacity of ammonia clearance because ammonia binds to glutamate to generate glutamine.Our findings are in line with a recent study in rats with bile duct ligation, which showed the multistrain probiotic used here ameliorated locomotor activity and improved the neurometabolic profile assessed by in vivo brain ultrahigh field The exact mechanisms underlying the increase in the glutamine/glutamate ratio cannot be elucidated from the present study. One possible mechanism is that the probiotic could induce a decrease in glutaminase activity or an increase in glutamine synthetase activity, as has been observed in experimental models with other treatments for HE, such as rifaximinRegarding gut microbiota composition, with the limitations of the small sample size, here we focused on the glutamine/glutamate ratio and found that higher values in blood were associated with lower abundance of In conclusion, metabolomic analysis in patients with cirrhosis treated with this multistrain probiotic showed an increase in the serum glutamine/glutamate ratio. This finding contributes to the understanding of the mechanisms involved in the effects of this probiotic and could help in the design of new approaches to improve patients’ outcomes and health-related quality of life.