title: Evaluation of Oxidant-Antioxidant Balance in Children with Atopic Dermatitis: A Case-Control Study.
abstract: BACKGROUND
  Increased reactive oxygen species (ROS) and oxidative stress (OS) has been reported in many allergic and inflammatory skin diseases, including urticaria, psoriasis, and atopic dermatitis (AD). Melatonin is a hormone secreted from the pineal gland and is a potent antioxidant.
  
  
  OBJECTIVE
  The aim of the study was to measure serum antioxidant melatonin, oxidants of nitric oxide (NO), and malondialdehyde levels to calculate the serum oxidant-antioxidant balance based on the NO/melatonin and malondialdehyde/melatonin ratios and to determine the correlation with the disease severity in children with AD.
  
  
  METHODS
  Seventy-three children with AD and 67 healthy controls were included in the study. The clinical diagnosis of AD was based on the diagnostic criteria of Hanifin-Rajka. The severity of AD was evaluated by the scoring AD (SCORAD) index, and atopy was determined by skin prick tests (SPTs) with commercial extracts. The OS-related parameters of serum melatonin, NO, malondialdehyde, and the NO/melatonin and malondialdehyde/melatonin ratios were calculated and compared with the results of healthy controls.
  
  
  RESULTS
  Serum melatonin levels were higher (p < 0.0001) and serum NO levels and the NO/melatonin and malondialdehyde/melatonin ratios were lower in children with AD than in healthy controls (p = 0.045, p < 0.0001, p < 0.0001, respectively). There was no difference between children with AD and healthy controls in terms of serum malondialdehyde levels (p = 0.119). Serum melatonin levels were significantly lower in severe AD than in mild AD (p = 0.012). However, in terms of serum melatonin levels, there was no difference between mild and moderate AD (p = 0.742) and moderate to severe AD (p = 0.301). There was no significant difference in serum NO and malondialdehyde levels and NO/melatonin and malondialdehyde/melatonin ratios among children with mild, moderate, and severe AD (p > 0.05). A negative correlation was found between serum melatonin levels and the SCORAD index (r = -0.252, p = 0.031), and a positive correlation was found between NO/melatonin and malondialdehyde/melatonin ratios (r = 0.511, p < 0.0001). There was no statistically significant relationship between age (≤24 or >24 months), disease duration (≤6 or >6 months), and sex for the OS-related parameters (p > 0.05).
  
  
  CONCLUSIONS
  The serum oxidant-antioxidant balance was impaired in children with AD. Serum melatonin levels were higher in children with AD; however, this was negatively correlated with disease severity. Serum NO levels and NO/melatonin and malondialdehyde/melatonin ratios were lower in children with AD than in healthy controls. Melatonin might be used as a promising antioxidant to evaluate disease severity in children with AD. Thus, further studies are needed to clarify the role of melatonin in AD pathogenesis.
authors.affiliation: Department of Pediatric Allergy and Immunology, Adnan Menderes University Hospital, 09200, Aydın, Turkey. druysal.pinar@gmail.com.
authors.forename: Pınar
authors.identifier: http://orcid.org/0000-0003-0288-608X
authors.initials: P
authors.lastname: Uysal
authors.affiliation: Department of Child and Adolescent Psychiatry, Adnan Menderes University Hospital, 09200, Aydın, Turkey.
authors.forename: Sibelnur
authors.initials: S
authors.lastname: Avcil
authors.affiliation: Department of Biochemistry, Adnan Menderes University Hospital, 09200, Aydın, Turkey.
authors.forename: Burçin İrem
authors.initials: Bİ
authors.lastname: Abas
authors.affiliation: Department of Biochemistry, Adnan Menderes University Hospital, 09200, Aydın, Turkey.
authors.forename: Çiğdem
authors.initials: Ç
authors.lastname: Yenisey
mesh_terms: D000293:Adolescent; D000975:Antioxidants / Q000378:metabolism*; D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003876:Dermatitis, Atopic / Q000097:blood* / Q000473:pathology; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008550:Melatonin / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism*; D018384:Oxidative Stress / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012720:Severity of Illness Index
chemical_list: D000975:Antioxidants; D016877:Oxidants; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D008315:Malondialdehyde; D008550:Melatonin