Fig 1.
The kynurenine pathway of tryptophan metabolism.
IDO, indoleamine 2,3-dioxygenase; TDO, tryptophan 2,3-dioxygenase; KAT, kynurenine aminotransaminase; KMO, kynurenine 3-monooxygenase; KYNU, kynureninase; 3OH-kynurenine, 3-hydroxy kynurenine; 3OH-anthranilic acid, 3-hydroxy anthranilic acid; B6, vitamin B6 (pyridoxal 5`-phosphate); B2, vitamin B2 (flavin adenine dinucleotide).
Table 1.
Baseline characteristics of the study population according to bariatric surgical procedures.
Table 2.
Circulating levels of kynurenines, neopterin and B vitamins at inclusion of patients undergoing bariatric surgery.
Fig 2.
Correlations of fasting glucose, HbA1c and the triglyceride:HDL ratio with tryoptophan, kynurenine and the kynurenine metabolites, inflammatory markers, vitamin B6 and vitamin B3 at baseline.
Regression coefficient based on Spearman rank correlation test, corrected for age, gender and eGFR, are shown in the figure. Tg, triglyceride; HDL, high density lipoprotein; Trp, tryptophan; Kyn, kynurenine; KA kynurenic acid; AA, anthranilic acid; HK, 3-hydroxy kynurenine; XA, xanthurenic acid; HAA, 3-hydroxy anthranilic acid; QA, quinolinic acid; KTR, kynurenine:tryptophan ratio; PLP, pyridoxal 5`-phosphate. *p-value < 0.05; **p-value < 0.005.
Table 3.
Patient characteristics at inclusion and after bariatric surgery.
Fig 3.
Inflammatory markers after bariatric surgery.
Samples were measured at baseline, 3 months and after one year in 37 patients undergoing bariatric surgery. P values for trend over time are estimated with a random intercept mixed model, adjusted for type of operation and vitamin B supplementation. Data are given as median (25th to 27th percentile).
Table 4.
Circulating levels of tryptophan, kynurenines and B vitamins before and after bariatric surgery.