OBJECTIVE: The essential amino acid L-methionine is a potential compound in the prophylaxis of recurrent or relapsing urinary tract infection due to acidification of urine. As an intermediate of L-methionine metabolism, homocysteine is formed. The objective was to study the metabolism of L-methionine and homocysteine, and to assess whether there are differences between patients with chronic urinary tract infection and healthy control subjects. DESIGN: A randomized placebo-controlled double-blind intervention study with cross-over design. SETTING: Department of Nutritional Physiology, Institute of Nutrition in cooperation with the Department of Internal Medicine III, Friedrich Schiller University of Jena, Germany. SUBJECTS:Eight female patients with chronic urinary tract infection and 12 healthy women (controls). INTERVENTIONS: After a methionine-loading test, the volunteers received 500 mg L-methionine or a placebo three times daily for 4 weeks. MAIN OUTCOME MEASURES: Serum and urinary concentrations of methionine, homocysteine, cystathionine, cystine, serine, glycine and serum concentrations of vitamin B12, B6 and the state of folate. RESULTS:Homocysteine plasma concentrations increased from 9.4+/-2.7 micromol/l (patients) and 8.9+/-1.8 micromol/l (controls) in the placebo period to 11.2+/-4.1 micromol/l (P=0.031) and 11.0+/-2.3 micromol/l (P=0.000), respectively, during L-methionine supplementation. There were significant increases in serum methionine (53.6+/-22.0 micromol/l; P=0.003; n=20) and cystathionine (0.62+/-0.30 micromol/l; P=0.000; n=20) concentrations compared with the placebo period (33.0+/-12.0 and 0.30+/-0.10 micromol/l; n=20). Simultaneously, renal excretion of methionine and homocysteine was significantly higher during L-methionine intake. CONCLUSIONS: Despite an adequate vitamin status, the supplementation of 1500 mg of L-methionine daily significantly increases homocysteine plasma concentrations by an average of 2.0 micromol/l in patients and in control subjects. An optimal vitamin supplementation, especially with folate, might prevent such an increase.
RCT Entities:
OBJECTIVE: The essential amino acid L-methionine is a potential compound in the prophylaxis of recurrent or relapsing urinary tract infection due to acidification of urine. As an intermediate of L-methionine metabolism, homocysteine is formed. The objective was to study the metabolism of L-methionine and homocysteine, and to assess whether there are differences between patients with chronic urinary tract infection and healthy control subjects. DESIGN: A randomized placebo-controlled double-blind intervention study with cross-over design. SETTING: Department of Nutritional Physiology, Institute of Nutrition in cooperation with the Department of Internal Medicine III, Friedrich Schiller University of Jena, Germany. SUBJECTS: Eight female patients with chronic urinary tract infection and 12 healthy women (controls). INTERVENTIONS: After a methionine-loading test, the volunteers received 500 mg L-methionine or a placebo three times daily for 4 weeks. MAIN OUTCOME MEASURES: Serum and urinary concentrations of methionine, homocysteine, cystathionine, cystine, serine, glycine and serum concentrations of vitamin B12, B6 and the state of folate. RESULTS:Homocysteine plasma concentrations increased from 9.4+/-2.7 micromol/l (patients) and 8.9+/-1.8 micromol/l (controls) in the placebo period to 11.2+/-4.1 micromol/l (P=0.031) and 11.0+/-2.3 micromol/l (P=0.000), respectively, during L-methionine supplementation. There were significant increases in serum methionine (53.6+/-22.0 micromol/l; P=0.003; n=20) and cystathionine (0.62+/-0.30 micromol/l; P=0.000; n=20) concentrations compared with the placebo period (33.0+/-12.0 and 0.30+/-0.10 micromol/l; n=20). Simultaneously, renal excretion of methionine and homocysteine was significantly higher during L-methionine intake. CONCLUSIONS: Despite an adequate vitamin status, the supplementation of 1500 mg of L-methionine daily significantly increases homocysteine plasma concentrations by an average of 2.0 micromol/l in patients and in control subjects. An optimal vitamin supplementation, especially with folate, might prevent such an increase.
Authors: A Innamaa; L Jackson; V Asher; G van Schalkwyk; A Warren; A Keightley; D Hay; A Bali; H Sowter; R Khan Journal: Clin Transl Oncol Date: 2013-03-12 Impact factor: 3.405
Authors: Joerg H Holstein; Julia Schmalenbach; Markus Herrmann; Ilona Ölkü; Patric Garcia; Tina Histing; Wolfgang Herrmann; Michael D Menger; Tim Pohlemann; Lutz Claes Journal: Med Sci Monit Date: 2012-12