Xanthurenic Acid Excretion in Urine After Oral Intake of 5 Gram <i>L</i>-Tryptophan by Healthy Volunteers: Standardisation of the Reference Values

Hoes, M.J.A.J.M.; Kreutzer, E.K.J.; Sijben, N.

doi:10.1515/cclm.1981.19.5.259

Cited by 2 publications

(1 citation statement)

References 8 publications

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“…Fasting and post-methionine load plasma tHcy concentrations [ 21 ] and 4-PA [ 22 ] were determined by high performance liquid chromatography (HPLC) using a Hitachi L-7100 intelligent pump connected to an L-7400 UV detector (Hitachi, Tokyo, Japan). Baseline and post-tryptophan load urinary XA were measured by a colorimetric method [ 23 ]. EAST activity was measured using the Cobas Fara II Centrifugal Analyzer (Roche Dianostic system Inc., Nutley, NJ, USA) [ 24 ].…”

Section: Methodsmentioning

confidence: 99%

Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis

Chiang¹,

Selhub

Bagley

et al. 2005

Arthritis Res Ther

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Patients with rheumatoid arthritis have subnormal vitamin B6 status, both quantitatively and functionally. Abnormal vitamin B6 status in rheumatoid arthritis has been associated with spontaneous tumor necrosis factor (TNF)-α production and markers of inflammation, including C-reactive protein and erythrocyte sedimentation rate. Impaired vitamin B6 status could be a result of inflammation, and these patients may have higher demand for vitamin B6. The aim of this study was to determine if daily supplementation with 50 mg of pyridoxine for 30 days can correct the static and/or the functional abnormalities of vitamin B6 status seen in patients with rheumatoid arthritis, and further investigate if pyridoxine supplementation has any effects on the pro-inflammatory cytokine TNF-α or IL-6 production of arthritis. This was a double-blinded, placebo-controlled study involving patients with rheumatoid arthritis with plasma pyridoxal 5'-phosphate below the 25th percentile of the Framingham Heart Cohort Study. Vitamin B6 status was assessed via plasma and erythrocyte pyridoxal 5'-phosphate concentrations, the erythrocyte aspartate aminotransferase activity coefficient (αEAST), net homocysteine increase in response to a methionine load test (ΔtHcy), and 24 h urinary xanthurenic acid (XA) excretion in response to a tryptophan load test. Urinary 4-pyridoxic acid (4-PA) was measured to examine the impact of pyridoxine treatment on vitamin B6 excretion in these patients. Pro-inflammatory cytokine (TNF-α and IL-6) production, C-reactive protein levels and the erythrocyte sedimentation rate before and after supplementation were also examined. Pyridoxine supplementation significantly improved plasma and erythrocyte pyridoxal 5'-phosphate concentrations, erythrocyte αEAST, urinary 4-PA, and XA excretion. These improvements were apparent regardless of baseline B6 levels. Pyridoxine supplementation also showed a trend (p < 0.09) towards a reduction in post-methionine load ΔtHcy. Supplementation did not affect pro-inflammatory cytokine production. Although pyridoxine supplementation did not suppress pro-inflammatory cytokine production in patients with rheumatoid arthritis, the suboptimal vitamin B6 status seen in rheumatoid arthritis can be corrected by 50 mg pyridoxine supplementation for 30 days. Data from the present study suggest that patients with rheumatoid arthritis may have higher requirements for vitamin B6 than those in a normal healthy population.

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Section: Methodsmentioning

confidence: 99%

Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis

Chiang¹,

Selhub

Bagley

et al. 2005

Arthritis Res Ther

View full text Add to dashboard Cite

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The clinical significance of disordered renal excretion of xanthurenic acid in depressive patients

Hoes

Sijben

1981

Psychopharmacology

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Xanthurenic acid is a metabolite of L-tryptophanicotinic acid ribonucleotide biosynthesis. The excretion of xanthurenic acid from urine 24 h after ingestion of 5 g L-tryptophan is increased in depressive patients, and 17-hydroxycorticosteroids are considered of primary importance to this disorder. However, in this study, the excretion of xanthurenic acid and 17-hydroxycorticosteroids did not correlate with the scores of the Raskin depression scale, Hamilton depression scale, Zung depression scale, or the Zung anxiety scale in depressive patients. The patients were treated with either pyridoxine plus L-tryptophan, a presumably serotonin-enhancing treatment (n = 10) or maprotiline, a noradrenaline-enhancing drug (n = 10). Repeated measurements showed no differences between treatments after 2 or 4 weeks of treatment. The improvement in xanthurenic acid excretion precedes clinical improvements in depression. The excretion of xanthurenic acid only at 2 weeks correlated significantly with the anxiety and depression scores at 4 weeks, making prediction of clinical improvement possible. The neurobiological mode of action on noradrenergic or serotonergic neurons of antidepressant medication is of questionable significance to their therapeutic effect.

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Xanthurenic Acid Excretion in Urine After Oral Intake of 5 Gram L-Tryptophan by Healthy Volunteers: Standardisation of the Reference Values

Cited by 2 publications

References 8 publications

Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis

Pyridoxine supplementation corrects vitamin B6 deficiency but does not improve inflammation in patients with rheumatoid arthritis

The clinical significance of disordered renal excretion of xanthurenic acid in depressive patients

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