title: The association of cysteine with obesity, inflammatory cytokines and insulin resistance in Hispanic children and adolescents.
abstract: BACKGROUND
  Plasma total cysteine (tCys) independently relates to fat mass in adults. Dietary cyst(e)ine promotes adiposity and decreases glucose tolerance in some rodent models, but alleviates insulin resistance in others.
  
  
  OBJECTIVE
  To investigate whether the association of tCys with body fat extends to children at particular risk of obesity, and whether tCys is associated with insulin resistance and obesity-associated inflammation.
  
  
  METHODS
  We explored the cross-sectional relations of fasting plasma tCys and related metabolites with body composition measured by dual-energy X-ray absorptiometry in 984 Hispanic children and adolescents aged 4-19 years from the Viva La Familia Study. Linear and logistic regression and dose-response curves were used to evaluate relations of tCys with obesity, insulin resistance and inflammatory markers including interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), monocyte chemoattractant protein-1 (MCP-1) and C-reactive protein (CRP).
  
  
  RESULTS
  tCys, methionine and total homocysteine (tHcy) increased with age. Upper tCys quartile was independently associated with a 5-fold increased risk of obesity (95% CI 3.5-8.0, P<0.001), and 2-fold risk of insulin resistance (95% CI: 1.6-5.0, P<0.001; adjusted for body fat%). Within the overweight/obese subgroup, but not in normal-weight children, tCys accounted for 9% of the variability in body fat% (partial r = 0.30, P<0.001; adjusted for age and gender). tCys correlated positively with serum non-esterified fatty acids and leptin, partly independent of body fat, but was not associated with serum IL-6, TNF-α or MCP-1. A positive correlation with CRP disappeared after adjustment for BMI.
  
  
  CONCLUSIONS
  tCys is independently associated with obesity and insulin resistance in Hispanic children and adolescents, highlighting a previously underappreciated link between the sulfur amino acid metabolic pathway and obesity and cardiometabolic risk.
authors.affiliation: Department of Pharmacology, University of Oxford, Oxford, United Kingdom. amany.elshorbagy@pharm.ox.ac.uk
authors.forename: Amany K
authors.initials: AK
authors.lastname: Elshorbagy
authors.forename: Maria
authors.initials: M
authors.lastname: Valdivia-Garcia
authors.forename: Helga
authors.initials: H
authors.lastname: Refsum
authors.forename: Nancy
authors.initials: N
authors.lastname: Butte
mesh_terms: D054392:Adipokines / Q000097:blood; D000273:Adipose Tissue / Q000473:pathology; D000293:Adolescent; D000886:Anthropometry; D015415:Biomarkers / Q000097:blood; D001823:Body Composition; D002648:Child; D003545:Cysteine / Q000097:blood*; D016207:Cytokines / Q000097:blood*; D005260:Female; D006630:Hispanic or Latino; D006801:Humans; D018836:Inflammation Mediators / Q000097:blood*; D007333:Insulin Resistance; D008297:Male; D009765:Obesity / Q000097:blood* / Q000473:pathology; D016017:Odds Ratio; D050177:Overweight / Q000097:blood / Q000473:pathology; D055815:Young Adult
chemical_list: D054392:Adipokines; D015415:Biomarkers; D016207:Cytokines; D018836:Inflammation Mediators; D003545:Cysteine