title: No effect of different bariatric surgery procedures on LINE-1 DNA methylation in diabetic and nondiabetic morbidly obese patients.
abstract: BACKGROUND
  Bariatric surgery (BS) is proposed as a highly effective therapy for reducing weight and improving obesity-related co-morbidities. The molecular mechanisms involved in the metabolic improvement after BS are not completely resolved. Epigenetic modifications could have an important role.
  
  
  OBJECTIVE
  The aim of this study was to evaluate the effect of different BS procedures (Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy) on global DNA methylation (long interspersed nucleotide element 1 [LINE-1]) in a group of nondiabetic and diabetic severely obese patients.
  
  
  METHODS
  University hospital, Spain.
  
  
  METHODS
  This study included 60 patients (30 nondiabetic and 30 diabetic severely obese patients) undergoing BS: 31 patients underwent Roux-en-Y gastric bypass and 29 underwent laparoscopic sleeve gastrectomy. Before and 6 months post-BS, anthropometric data, blood pressure, and metabolic parameters were determined. LINE-1 DNA methylation was quantified by pyrosequencing. We used the methylation levels of tumor necrosis factor-α as a control gene promoter.
  
  
  RESULTS
  There were no differences between LINE-1 methylation levels at baseline and at 6 months after surgery (66.3±1.6 versus 66.2±2.06). Likewise, there was no statistically significant difference on LINE-1 methylation levels when we stratified according to metabolic status (diabetic versus nondiabetic), nor was there regarding the BS procedure. A strong correlation was shown between LINE-1 methylation levels and weight at baseline both in diabetic and nondiabetic obese patients (r = .486; P<.001). Tumor necrosis factor-α methylation levels increased significantly after BS in the group of diabetic obese patients.
  
  
  CONCLUSIONS
  After BS, global LINE-1 methylation is not modified in the short term. More studies are required to determine if LINE-1 is a stable epigenetic marker, or, on the contrary, if it is susceptible to modification by external factors such as changes in lifestyle or a surgical intervention.
authors.affiliation: Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Clínico Virgen de la Victoria, Málaga, Spain.
authors.forename: G M
authors.initials: GM
authors.lastname: Martín-Núñez
authors.affiliation: Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Clínico Virgen de la Victoria, Málaga, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Cabrera-Mulero
authors.affiliation: Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Clínico Virgen de la Victoria, Málaga, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Alcaide-Torres
authors.affiliation: Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Regional Universitario, Málaga, Spain; CIBER Pathophysiology of Obesity and Nutrition, Málaga, Spain.
authors.forename: E
authors.initials: E
authors.lastname: García-Fuentes
authors.affiliation: Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Clínico Virgen de la Victoria, Málaga, Spain; CIBER Pathophysiology of Obesity and Nutrition, Málaga, Spain. Electronic address: fjtinahones@hotmail.com.
authors.forename: F J
authors.initials: FJ
authors.lastname: Tinahones
authors.affiliation: Unidad de Gestión Clínica de Endocrinología y Nutrición, Instituto de Investigación Biomédica de Málaga (IBIMA), Hospital Clínico Virgen de la Victoria, Málaga, Spain; CIBER Pathophysiology of Obesity and Nutrition, Málaga, Spain. Electronic address: sonsoles75@gmail.com.
authors.forename: S
authors.initials: S
authors.lastname: Morcillo
mesh_terms: D000328:Adult; D050110:Bariatric Surgery; D019175:DNA Methylation / Q000235:genetics; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000235:genetics*; D005260:Female; D005743:Gastrectomy; D015390:Gastric Bypass; D006801:Humans; D010535:Laparoscopy; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008297:Male; D009767:Obesity, Morbid / Q000150:complications / Q000235:genetics*; D011182:Postoperative Care; D011401:Promoter Regions, Genetic / Q000235:genetics
keywords: Bariatric surgery; Diabetes; Global DNA methylation; LINE-1 levels; Severe obesity