Marc Beisani1, Stella Pappa2, Pau Moreno3, Eva Martínez4, Jordi Tarascó5, Maria Luisa Granada6, Rocío Puig7, Manel Cremades8, Manel Puig-Domingo9, Mireia Jordà10, Silvia Pellitero11, José M Balibrea12. 1. Department of Surgery, Hospital del Mar, Barcelona, Spain; Centre de Recerca Experimental Biomèdica Aplicada (CREBA), Lleida, Spain. Electronic address: mbeisani@gmail.com. 2. Program of Predictive and Personalized Medicine of Cancer, Germans Trias i Pujol Research Institute (PMPPC-IGTP), Badalona, Spain. Electronic address: spabmc@ibmb.csic.es. 3. Department of Surgery, Germans Trias i Pujol University, Hospital and Research Institute, Badalona, Spain. Electronic address: paumorenos@gmail.com. 4. Endocrinology and Nutrition Service, Department of Medicine, Universitat Autònoma de Barcelona, Germans Trias i Pujol University, Hospital and Research Institute, Badalona, Spain. Electronic address: emarlo78@gmail.com. 5. Department of Surgery, Germans Trias i Pujol University, Hospital and Research Institute, Badalona, Spain. Electronic address: jtarasco@hotmail.com. 6. Clinical Biochemistry Service, Germans Trias i Pujol University, Hospital and Research Institute, Badalona, Spain. Electronic address: mgranada.germanstrias@gencat.cat. 7. Endocrinology and Nutrition Service, Department of Medicine, Universitat Autònoma de Barcelona, Germans Trias i Pujol University, Hospital and Research Institute, Badalona, Spain. Electronic address: ropuig@gmail.com. 8. Department of Surgery, Germans Trias i Pujol University, Hospital and Research Institute, Badalona, Spain. Electronic address: lolo_cremades@hotmail.com. 9. Endocrinology and Nutrition Service, Department of Medicine, Universitat Autònoma de Barcelona, Germans Trias i Pujol University, Hospital and Research Institute, Badalona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain; CIBER de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain. Electronic address: mpuigd@igtp.cat. 10. Program of Predictive and Personalized Medicine of Cancer, Germans Trias i Pujol Research Institute (PMPPC-IGTP), Badalona, Spain. Electronic address: mjorda@igtp.cat. 11. Endocrinology and Nutrition Service, Department of Medicine, Universitat Autònoma de Barcelona, Germans Trias i Pujol University, Hospital and Research Institute, Badalona, Spain; CIBER de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain. Electronic address: spelli75@gmail.com. 12. Endocrine, Metabolic and Bariatric Surgery Unit (EAC-BS Center of Excellence), Vall d'Hebron University Hospital, Universitat Autònoma de Barcelona, Barcelona, Spain. Electronic address: balibrea@gmail.com.
Abstract
BACKGROUND & AIMS: Peripheral white blood cells (PWBC) may allow for the development of obesity biomarkers. We aimed to investigate the existence of gene expression and DNA methylation changes in PWBC after a very low calorie diet (VLCD) followed by a laparoscopic sleeve gastrectomy (LSG), and its correlation with surgical outcomes. METHODS: From July 2013 to June 2014, 35 consecutive bariatric patients and 33 healthy lean volunteers were recruited. Molecular data was obtained once on the control group and at 3 different times on the LSG group: 1) at baseline; 2) after 2 weeks of VLCD, right before LSG; and 3) 6 months after LSG. The expression of 12 genes in PWBC was analyzed by quantitative real-time polymerase chain reaction: ghrelin (GHRL), visfatin (NAMPT), insulin receptor substrate 1 (IRS1), fat mass and obesity-related gene (FTO), leptin (LEP), peroxisome proliferator-activated receptor gamma (PPARG), adiponectin (ADIPOQ), fatty acid synthase (FASN), melanocortin 4 receptor (MC4R), fas cell surface death receptor (FAS), tumor necrosis factor alpha (TNF) and chemokine (C-C motif) ligand 2 (CCL2). Moreover, DNA methylation of GHRL, NAMPT and FAS promoters was analyzed in PWBC by bisulfite pyrosequencing. RESULTS: Seven genes (GHRL, NAMPT, IRS1, FTO, FAS, TNF and CCL2) had detectable expression in PWBC. FTO expression at baseline was lower in patients than in controls (p = 0.042), equalizing after LSG. In patients, FAS expression decreased after VLCD (p = 0.01) and stayed low after LSG (p = 0.015). Also, CCL2 expression decreased 50% after LSG compared to pre-surgical levels (p = 0.016). All studied CpG sites in the GHRL gene promoter followed a consistent pattern of DNA methylation/demethylation. No direct correlation between these molecular changes and surgical outcomes was found at 1-year follow-up. CONCLUSIONS: FTO expression increased and FAS and CCL2 expression decreased in PWBC after LSG. Molecular changes did not correlate with surgical outcomes.
BACKGROUND & AIMS: Peripheral white blood cells (PWBC) may allow for the development of obesity biomarkers. We aimed to investigate the existence of gene expression and DNA methylation changes in PWBC after a very low calorie diet (VLCD) followed by a laparoscopic sleeve gastrectomy (LSG), and its correlation with surgical outcomes. METHODS: From July 2013 to June 2014, 35 consecutive bariatric patients and 33 healthy lean volunteers were recruited. Molecular data was obtained once on the control group and at 3 different times on the LSG group: 1) at baseline; 2) after 2 weeks of VLCD, right before LSG; and 3) 6 months after LSG. The expression of 12 genes in PWBC was analyzed by quantitative real-time polymerase chain reaction: ghrelin (GHRL), visfatin (NAMPT), insulin receptor substrate 1 (IRS1), fat mass and obesity-related gene (FTO), leptin (LEP), peroxisome proliferator-activated receptor gamma (PPARG), adiponectin (ADIPOQ), fatty acid synthase (FASN), melanocortin 4 receptor (MC4R), fas cell surface death receptor (FAS), tumor necrosis factor alpha (TNF) and chemokine (C-C motif) ligand 2 (CCL2). Moreover, DNA methylation of GHRL, NAMPT and FAS promoters was analyzed in PWBC by bisulfite pyrosequencing. RESULTS: Seven genes (GHRL, NAMPT, IRS1, FTO, FAS, TNF and CCL2) had detectable expression in PWBC. FTO expression at baseline was lower in patients than in controls (p = 0.042), equalizing after LSG. In patients, FAS expression decreased after VLCD (p = 0.01) and stayed low after LSG (p = 0.015). Also, CCL2 expression decreased 50% after LSG compared to pre-surgical levels (p = 0.016). All studied CpG sites in the GHRL gene promoter followed a consistent pattern of DNA methylation/demethylation. No direct correlation between these molecular changes and surgical outcomes was found at 1-year follow-up. CONCLUSIONS:FTO expression increased and FAS and CCL2 expression decreased in PWBC after LSG. Molecular changes did not correlate with surgical outcomes.