title: Soluble fatty acid synthase relates to bone biomarkers in prepubertal children.
abstract: CONCLUSIONS
  Circulating soluble fatty acid synthase (FASN, a key enzyme in de novo biosynthesis of fatty acids, expressed in both adipocytes and osteoblasts) is clinically related to a less favorable bone profile in healthy prepubertal children. Soluble FASN may participate in the reciprocal regulation between fat and bone metabolism.
  
  
  BACKGROUND
  Fatty acid synthase (FASN), a key enzyme in de novo biosynthesis of fatty acids, is expressed in adipocytes and osteoblasts. We hypothesized that FASN may participate in the crosstalk between fat and bone. To this aim, we studied the relation between circulating soluble FASN (an extracellular FASN that reflects previously intracellular enzymatic activity) and adipose tissue and bone biomarkers in prepubertal children.
  
  
  METHODS
  Circulating soluble FASN, total and high molecular weight (HMW) adiponectin, bone biomarkers [osteocalcin (OC), uncarboxylated osteocalcin (ucOC), C-terminal cross-linked telopeptide of type I collagen (CTX), bone-specific alkaline phosphatase (BSAP)], and a profile of energy metabolism [body fat, insulin resistance and secretion (HOMA), serum lipids] were assessed in 84 asymptomatic prepubertal children (44 girls, 40 boys, age 6.8 ± 0.1 year). Serum 25-OH Vitamin D (Vit D) was additionally measured.
  
  
  RESULTS
  Circulating soluble FASN increased with increasing HMW adiponectin (r = 0.29, p = 0.01) and decreasing serum Vit D (r = -0.21, p < 0.05), and was related to a less favorable bone profile, showing negative associations with bone-derived metabolic parameters [total OC (r = -0.33, p = 0.002) and ucOC (r = -0.37, p < 0.0001)] and a positive association with the CTX-to-BSAP ratio (r = 0.31, p < 0.01). These correlations were not explained by age, gender, body fat, insulin resistance or secretion or serum lipids; however, they were predominant in those subjects with Vit D levels below the population median.
  
  
  CONCLUSIONS
  Circulating soluble FASN relates to both adipose tissue and bone biomarkers in prepubertal children, with associations that are dependent on Vit D concentrations. These findings suggest that FASN may participate in the crosstalk between fat and bone metabolism.
authors.affiliation: Pediatric Endocrinology, Dr. Josep Trueta Hospital, Av. Francia s/n, 17007, Girona, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Prats-Puig
authors.forename: T
authors.initials: T
authors.lastname: Puig
authors.forename: C
authors.initials: C
authors.lastname: Sitjar
authors.forename: M
authors.initials: M
authors.lastname: Mas-Parareda
authors.forename: P
authors.initials: P
authors.lastname: Grau-Cabrera
authors.forename: P
authors.initials: P
authors.lastname: Soriano-Rodríguez
authors.forename: M
authors.initials: M
authors.lastname: Montesinos-Costa
authors.forename: M
authors.initials: M
authors.lastname: Diaz
authors.forename: F
authors.initials: F
authors.lastname: de Zegher
authors.forename: L
authors.initials: L
authors.lastname: Ibáñez
authors.forename: J
authors.initials: J
authors.lastname: Bassols
authors.forename: A
authors.initials: A
authors.lastname: López-Bermejo
mesh_terms: D052242:Adiponectin / Q000097:blood; D000273:Adipose Tissue / Q000378:metabolism; D000469:Alkaline Phosphatase / Q000097:blood; D000886:Anthropometry / Q000379:methods; D015415:Biomarkers / Q000097:blood; D001842:Bone and Bones / Q000378:metabolism*; D002648:Child; D024042:Collagen Type I / Q000097:blood; D004734:Energy Metabolism / Q000502:physiology; D054890:Fatty Acid Synthase, Type I / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D015675:Osteocalcin / Q000097:blood; D010455:Peptides / Q000097:blood; D012995:Solubility; D014807:Vitamin D / Q000097:blood
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D024042:Collagen Type I; D010455:Peptides; C052929:collagen type I trimeric cross-linked peptide; D015675:Osteocalcin; D014807:Vitamin D; C518729:FASN protein, human; D054890:Fatty Acid Synthase, Type I; D000469:Alkaline Phosphatase