Suplementação com vitamina C em crianças com Osteogênese Imperfeita: estudo piloto de um ensaio clínico controlado e randomizado

• Autor(a) principal: Cebrian, Cinthia Faraco Martinez
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Universitário da Ânima (RUNA)
• Texto Completo: https://repositorio.animaeducacao.com.br/handle/ANIMA/3091
• topic: Osteogênese Imperfeita; Vitamina C; Dor; Qualidade de vida; Colágeno; Citocinas; Hidroxiprolina

Introduction: Osteogenesis imperfecta (OI) is a rare, congenital and hereditary disease. The main clinical feature is bone fragility; however, pain is also common, limits daily activities and affects quality of life. Supplementation with vitamin C is a possibility of complementary treatment that can contribute to the improvement of the symptoms of OI, since it is essential for the hydroxylation of proline during the synthesis of collagen, besides having already established anti-inflammatory function. Objectives: To evaluate the effect of supplementation with vitamin C or placebo on pain, quality of life, inflammation, collagen synthesis, bone turnover and fractures in children with IO in the use of pamidronate disodium. Methods: Randomized, double-blind, placebo-controlled pilot trial. After recruitment and evaluation of eligibility criteria, 54 children were randomized to receive either Placebo or Vitamin C supplementation. All evaluations were performed pre- and post-supplementation. The number of fractures was evaluated by chart analysis. Pain was assessed using the Face, Legs, Activity, Cry, Consolability (FLACC), Pain Scale-Revised (FPS-R) and Adolescent Pediatric Pain Tool (APPT) scales, appropriate for each age group. The questionnaires used to assess quality of life were the PedsQLTM Infant Scales and the PedsQLTM 4.0 Generic Core Scales. Serum concentrations of pro-inflammatory cytokines (TNF, IL-1β, IL-6 and MMP-9) and anti-inflammatory cytokines (IL-4 and IL-10), as well as TGF-β used as a marker of bone turnover, were evaluated by Enzyme-Linked Immunosorbent Assay (ELISA). The measurement of serum hydroxyproline concentration was performed by colorimetric reaction. Results: Vitamin C supplementation did not alter the number of fractures and the quality of life. The pain was present in only one child and was not altered with supplementation. Vitamin C did not alter serum levels of TNF, IL-1β, IL-6 and MMP-9. Serum IL-4 levels did not change, but an increase in IL-10 concentration was observed after vitamin C supplementation over baseline levels, whereas the placebo-supplemented group reduced post-supplementation serum levels (P = 0.0023). In addition, the Vitamin C group presented a higher concentration of hydroxyproline in relation to the Placebo group (P = 0.013) after supplementation. In the temporal analysis, the group supplemented with vitamin C increased serum hydroxyproline levels from baseline, whereas in the placebo group, serum levels decreased (P = 0.0005). Serum TGF-β1 levels did not change with supplementation. Conclusion: Vitamin C is associated with elevated serum levels of IL-10, an anti-inflammatory cytokine capable of reducing osteoclast activity. In addition to increasing serum levels of hydroxyproline, which may be due to increased production of collagen, a vitamin C dependent reaction. This can be understood as an improvement factor since the basic defect of OI lies in the production of collagen type I.