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Effects of l-Arginine Plus Vitamin C Supplementation on l-Arginine Metabolism in Adults with Long COVID: Secondary Analysis of a Randomized Clinical Trial.

  • 2023-03-07
  • International journal of molecular sciences 24(6)
    • Riccardo Calvani
    • Jacopo Gervasoni
    • Anna Picca
    • Francesca Ciciarello
    • Vincenzo Galluzzo
    • Hélio José Coelho-Júnior
    • Clara Di Mario
    • Elisa Gremese
    • Sara Lomuscio
    • Anna Maria Paglionico
    • Lavinia Santucci
    • Barbara Tolusso
    • Andrea Urbani
    • Federico Marini
    • Emanuele Marzetti
    • Francesco Landi
    • Matteo Tosato

Study Design

Type
Randomized Controlled Trial (RCT)
Population
adults with long COVID
Methods
randomized clinical trial, 28 days of l-arginine plus vitamin C or placebo supplementation
Duration
28 days
  • Rigorous Journal
Altered l-arginine metabolism has been described in patients with COVID-19 and has been associated with immune and vascular dysfunction. In the present investigation, we determined the serum concentrations of l-arginine, citrulline, ornithine, monomethyl-l-arginine (MMA), and symmetric and asymmetric dimethylarginine (SDMA, ADMA) in adults with long COVID at baseline and after 28-days of l-arginine plus vitamin C or placebo supplementation enrolled in a randomized clinical trial, compared with a group of adults without previous history of SARS-CoV-2-infection. l-arginine-derived markers of nitric oxide (NO) bioavailability (i.e., l-arginine/ADMA, l-arginine/citrulline+ornithine, and l-arginine/ornithine) were also assayed. Partial least squares discriminant analysis (PLS-DA) models were built to characterize systemic l-arginine metabolism and assess the effects of the supplementation. PLS-DA allowed discrimination of participants with long COVID from healthy controls with 80.2 ± 3.0% accuracy. Lower markers of NO bioavailability were found in participants with long COVID. After 28 days of l-arginine plus vitamin C supplementation, serum l-arginine concentrations and l-arginine/ADMA increased significantly compared with placebo. This supplement may therefore be proposed as a remedy to increase NO bioavailability in people with long COVID.

Research Insights

  • L-Arginine→Increased L-Arginine to ADMA Ratio

    After 28 days of l-arginine plus vitamin C supplementation, serum l-arginine concentrations and l-arginine/ADMA increased significantly compared with placebo.

    Effect
    Beneficial
    Effect size
    Small
  • L-Arginine→Increased L-arginine Level

    After 28 days of l-arginine plus vitamin C supplementation, serum l-arginine concentrations and l-arginine/ADMA increased significantly compared with placebo.

    Effect
    Beneficial
    Effect size
    Small
  • Vitamin C→Increased L-Arginine to ADMA Ratio

    After 28 days of l-arginine plus vitamin C supplementation, serum l-arginine concentrations and l-arginine/ADMA increased significantly compared with placebo.

    Effect
    Beneficial
    Effect size
    Small
  • Vitamin C→Increased L-arginine Level

    After 28 days of l-arginine plus vitamin C supplementation, serum l-arginine concentrations and l-arginine/ADMA increased significantly compared with placebo.

    Effect
    Beneficial
    Effect size
    Small
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