title: Relationships between desacylated and acylated ghrelin and insulin sensitivity in the metabolic syndrome.
abstract: BACKGROUND
  Metabolic syndrome shows clustered metabolic abnormalities with major roles for insulin resistance and obesity. Ghrelin is a gastric hormone whose total plasma concentration (T-Ghr) is associated positively with insulin sensitivity and is reduced in obesity. Ghrelin circulates in acylated (A-Ghr) and desacylated (D-Ghr) forms, but their potential differential associations with insulin resistance and whether they are differentially altered in obesity remain undefined.
  
  
  OBJECTIVE
  Our objective was to determine potential differential associations of ghrelin forms with insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)] and the impact of obesity on their plasma concentrations in metabolic syndrome.
  
  
  METHODS
  This is a cross-sectional study.
  
  
  METHODS
  The study was performed in a metabolic outpatient unit.
  
  
  METHODS
  Patients with metabolic syndrome (National Cholesterol Education Program-Adult Treatment Panel III; n = 45, 23 males/22 females) were included in the study.
  
  
  RESULTS
  The main study outcomes were metabolic syndrome criteria, HOMA-IR, and ghrelin forms.
  
  
  RESULTS
  Plasma insulin and HOMA-IR were associated negatively with T-Ghr and D-Ghr but positively with A-Ghr and acylated to desacylated ghrelin (A/D-Ghr) ratio (n = 45; P < 0.05). Compared with nonobese [body mass index (BMI) < 27.5 kg/m(2); n = 12, six males/six females], obese metabolic syndrome patients (BMI > 27.5 kg/m(2); n = 33) had lower T-Ghr and D-Ghr but comparable A-Ghr and higher A/D-Ghr ratio (P < 0.05). BMI and waist circumference (WC) were positively related with HOMA-IR (n = 45; P < 0.05). However, opposite associations between A/D-Ghr ratio and HOMA-IR remained significant after adjustment for sex and BMI (or WC). Additional obese individuals without metabolic syndrome (n = 10: age-, sex-, BMI-, and WC-matched to obese metabolic syndrome patients) had lower T-Ghr but higher A-Ghr (P < 0.05) compared with age-, sex-matched healthy nonobese counterparts (n = 15). T-Ghr and A-Ghr were comparable in obese with or without metabolic syndrome.
  
  
  CONCLUSIONS
  Obesity could alter circulating ghrelin profile, and relative A-Ghr excess could contribute to obesity-associated insulin resistance in metabolic syndrome.
authors.affiliation: Clinica Medica, Department of Clinical, Morphological and Technological Sciences, University of Trieste, Ospedale Cattinara, Strada di Fiume 447, 34127 Trieste, Italy. barazzon@units.it
authors.forename: Rocco
authors.initials: R
authors.lastname: Barazzoni
authors.forename: Michela
authors.initials: M
authors.lastname: Zanetti
authors.forename: Clara
authors.initials: C
authors.lastname: Ferreira
authors.forename: Pierandrea
authors.initials: P
authors.lastname: Vinci
authors.forename: Alessia
authors.initials: A
authors.lastname: Pirulli
authors.forename: Mariapia
authors.initials: M
authors.lastname: Mucci
authors.forename: Franca
authors.initials: F
authors.lastname: Dore
authors.forename: Maurizio
authors.initials: M
authors.lastname: Fonda
authors.forename: Beniamino
authors.initials: B
authors.lastname: Ciocchi
authors.forename: Luigi
authors.initials: L
authors.lastname: Cattin
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Guarnieri
mesh_terms: D000215:Acylation; D000886:Anthropometry; D008076:Cholesterol, HDL / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D054439:Ghrelin / Q000097:blood / Q000378:metabolism*; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007333:Insulin Resistance / Q000502:physiology*; D008297:Male; D024821:Metabolic Syndrome / Q000378:metabolism*; D008875:Middle Aged; D015999:Multivariate Analysis; D009765:Obesity / Q000378:metabolism*; D012044:Regression Analysis; D014280:Triglycerides / Q000097:blood
chemical_list: D008076:Cholesterol, HDL; D054439:Ghrelin; D014280:Triglycerides