title: Permanence of molecular features of obesity in subcutaneous adipose tissue of ex-obese subjects.
abstract: OBJECTIVE
  Bariatric surgery represents a powerful tool for morbid obesity treatment. However, after stabilization of weight loss that follows surgical interventions, ex-obese patients face the problem of residual tissues removal. Actually, it is unknown whether the characteristics of this residual subcutaneous adipose tissue (SAT) are 'restored' with regard to molecular and morphological features.
  
  
  METHODS
  To clarify this issue, we compared the SAT gene expression profile of ex-obese patients (ExOB-SAT, mean body mass index (BMI): 27.2±1.3 kg m(-2)) with that of lean (normal weight, NW-SAT, mean BMI: 22.6±1.1 kg m(-2)), overweight (OW-SAT, BMI: 27.65±0.2 kg m(-2)) and obese patients, according to BMI classes (OB1-SAT: 30 > or = BMI < or = 34.9, OB2-SAT: 35 > or = BMI < or = 39.9, OB3-SAT: BMI > or = 40).
  
  
  METHODS
  A total of 58 samples of SAT were collected during surgical interventions. Gene expression levels were assessed by microarrays and significant genes were validated by RT-qPCR. Adipocyte hypertrophy, inflammatory infiltration and fibrosis were assessed by morphological techniques.
  
  
  RESULTS
  Global gene expression in ExOB-SAT was closely related to gene expression of OB3-SAT by hierarchical clustering procedures, in spite of different BMI. Metallothioneins (MT1A and MT2A) were the key over-expressed genes in both groups. At morphologic level, adipocyte hypertrophy and inflammatory infiltration improved after weight loss in ExOB-SAT, despite a persistence of fibrosis.
  
  
  CONCLUSIONS
  Taken together, these results demonstrate that SAT gene expression is not fully restored, even after an extensive and stable weight loss. The persistence of 'obesity molecular features' in ExOB-SAT suggests that the molecular signature of adipose tissue is not solely dependent on weight loss and may need longer time period to completely disappear.
authors: Laboratory of Molecular Biology, IRCCS, Istituto Auxologico Italiano, Cusano Milanino, Milano, Italy. r.cancello@auxologico.it
authors: R
authors: R
authors: Cancello
authors: A
authors: A
authors: Zulian
authors: D
authors: D
authors: Gentilini
authors: M
authors: M
authors: Mencarelli
authors: A
authors: A
authors: Della Barba
authors: M
authors: M
authors: Maffei
authors: P
authors: P
authors: Vitti
authors: C
authors: C
authors: Invitti
authors: A
authors: A
authors: Liuzzi
authors: A M
authors: AM
authors: Di Blasio
mesh_terms: D017667:Adipocytes / Q000473:pathology*; D000328:Adult; D015992:Body Mass Index; D017558:Elective Surgical Procedures; D005260:Female; D015390:Gastric Bypass; D005786:Gene Expression Regulation; D006801:Humans; D006984:Hypertrophy; D007249:Inflammation / Q000473:pathology*; D007558:Italy / Q000453:epidemiology; D008297:Male; D008668:Metallothionein / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D009767:Obesity, Morbid / Q000453:epidemiology / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D012333:RNA, Messenger / Q000378:metabolism; D050151:Subcutaneous Fat / Q000473:pathology*; D013851:Thinness / Q000453:epidemiology / Q000235:genetics / Q000473:pathology* / Q000601:surgery; D013997:Time Factors; D016896:Treatment Outcome; D015431:Weight Loss / Q000235:genetics
chemical_list: C530099:MT1A protein, human; C491053:MT2A protein, human; D012333:RNA, Messenger; D008668:Metallothionein