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Effects of single and combined metformin and L-citrulline supplementation on L-arginine-related pathways in Becker muscular dystrophy patients: possible biochemical and clinical implications

Hanff E, Hafner P, Bollenbach A, Bonati U, Kayacelebi AA, Fischer D, Tsikas D

Amino acids, 2018

20 participants

Abstract

The L-arginine/nitric oxide synthase (NOS) pathway is considered to be altered in muscular dystrophy such as Becker muscular dystrophy (BMD). We investigated two pharmacological options aimed to increase nitric oxide (NO) synthesis in 20 male BMD patients (age range 21-44 years): (1) supplementation with L-citrulline (3 × 5 g/d), the precursor of L-arginine which is the substrate of neuronal NO synthase (nNOS); and (2) treatment with the antidiabetic drug metformin (3 × 500 mg/d) which activates nNOS in human skeletal muscle. We also investigated the combined use of L-citrulline (3 × 5 g/d) and metformin (3 × 500 mg/d). Before and after treatment, we measured in serum and urine samples the concentration of amino acids and metabolites of L-arginine-related pathways and the oxidative stress biomarker malondialdehyde (MDA). Compared to healthy subjects, BMD patients have altered NOS, arginine:glycine amidinotransferase (AGAT) and guanidinoacetate methyltransferase (GAMT) pathways. Metformin treatment resulted in concentration decrease of arginine and MDA in serum, and of homoarginine (hArg) and guanidinoacetate (GAA) in serum and urine. L-Citrulline supplementation resulted in considerable increase of the concentrations of amino acids and creatinine in the serum, and in their urinary excretion rates. Combined use of metformin and L-citrulline attenuated the effects obtained from their single administrations. Metformin, L-citrulline or their combination did not alter serum…

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Evidence Hub reads this as a clinical trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 20 participants or records.

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