title: The protective effect of the Mediterranean diet on endothelial resistance to GLP-1 in type 2 diabetes: a preliminary report.
abstract: BACKGROUND
  In type 2 diabetes, acute hyperglycemia worsens endothelial function and inflammation,while resistance to GLP-1 action occurs. All these phenomena seem to be related to the generation of oxidative stress. A Mediterranean diet, supplemented with olive oil, increases plasma antioxidant capacity, suggesting that its implementation can have a favorable effect on the aforementioned phenomena. In the present study, we test the hypothesis that a Mediterranean diet using olive oil can counteract the effects of acute hyperglycemia and can improve the resistance of the endothelium to GLP-1 action.
  
  
  METHODS
  Two groups of type 2 diabetic patients, each consisting of twelve subjects, participated in a randomized trial for three months, following a Mediterranean diet using olive oil or a control low-fat diet. Plasma antioxidant capacity, endothelial function, nitrotyrosine, 8-iso-PGF2a, IL-6 and ICAM-1 levels were evaluated at baseline and at the end of the study. The effect of GLP-1 during a hyperglycemic clamp, was also studied at baseline and at the end of the study.
  
  
  RESULTS
  Compared to the control diet, the Mediterranean diet increased plasma antioxidant capacity and improved basal endothelial function, nitrotyrosine, 8-iso-PGF2a, IL-6 and ICAM-1 levels. The Mediterranean diet also reduced the negative effects of acute hyperglycemia, induced by a hyperglycemic clamp, on endothelial function, nitrotyrosine, 8-iso-PGF2a, IL-6 and ICAM-1 levels. Furthermore, the Mediterranean diet improved the protective action of GLP-1 on endothelial function, nitrotyrosine, 8-iso-PGF2a, IL-6 and ICAM-1 levels, also increasing GLP-1-induced insulin secretion.
  
  
  CONCLUSIONS
  These data suggest that the Mediterranean diet, using olive oil, prevents the acute hyperglycemia effect on endothelial function, inflammation and oxidative stress, and improves the action of GLP-1, which may have a favorable effect on the management of type 2 diabetes, particularly for the prevention of cardiovascular disease.
authors.affiliation: Institut d' Investigación Biomédiques August Pi i Sunyer (IDIBAPS) and Centro de Investigación Biomedica en Red de Diabetes y Enfermedades Metabolicas Asociadas (CIBERDEM), Hospital Clinic, C/ Rosselló, 149-153, 08036, Barcelona, Spain. aceriell@clinic.ub.es.
authors.forename: Antonio
authors.initials: A
authors.lastname: Ceriello
authors.affiliation: Division of Metabolic Diseases, Center of Excellence for Cardiovascular Diseases, 2ndUniversity of Naples SUN, Naples, Italy. katherine.esposito@unina2.it.
authors.forename: Katherine
authors.initials: K
authors.lastname: Esposito
authors.affiliation: Institut d' Investigación Biomédiques August Pi i Sunyer (IDIBAPS) and Centro de Investigación Biomedica en Red de Diabetes y Enfermedades Metabolicas Asociadas (CIBERDEM), Hospital Clinic, C/ Rosselló, 149-153, 08036, Barcelona, Spain. LULASALA@clinic.ub.es.
authors.forename: Lucia
authors.initials: L
authors.lastname: La Sala
authors.affiliation: Institut d' Investigación Biomédiques August Pi i Sunyer (IDIBAPS) and Centro de Investigación Biomedica en Red de Diabetes y Enfermedades Metabolicas Asociadas (CIBERDEM), Hospital Clinic, C/ Rosselló, 149-153, 08036, Barcelona, Spain. GPUJADAS@clinic.ub.es.
authors.forename: Gemma
authors.initials: G
authors.lastname: Pujadas
authors.affiliation: Institut d' Investigación Biomédiques August Pi i Sunyer (IDIBAPS) and Centro de Investigación Biomedica en Red de Diabetes y Enfermedades Metabolicas Asociadas (CIBERDEM), Hospital Clinic, C/ Rosselló, 149-153, 08036, Barcelona, Spain. VNIGRIS@clinic.ub.es.
authors.forename: Valeria
authors.initials: V
authors.lastname: De Nigris
authors.affiliation: Experimental Models in Clinical Pathology, INRCA-IRCCS National Institute, Ancona, Italy. r.testa@inrca.it.
authors.forename: Roberto
authors.initials: R
authors.lastname: Testa
authors.affiliation: Department of Cardiovascular and Metabolic Diseases, IRCCS Gruppo Multimedica, Sesto San Giovanni, MI, Italy. loredana.bucciarelli@multimedica.it.
authors.forename: Loredana
authors.initials: L
authors.lastname: Bucciarelli
authors.affiliation: Department of Cardiovascular and Metabolic Diseases, IRCCS Gruppo Multimedica, Sesto San Giovanni, MI, Italy. maurizio.rondinelli@multimedica.it.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Rondinelli
authors.affiliation: Department of Cardiovascular and Metabolic Diseases, IRCCS Gruppo Multimedica, Sesto San Giovanni, MI, Italy. stefano.genovese@multimedica.it.
authors.forename: Stefano
authors.initials: S
authors.lastname: Genovese
mesh_terms: D000328:Adult; D000368:Aged; D001786:Blood Glucose / Q000378:metabolism; D002318:Cardiovascular Diseases / Q000517:prevention & control*; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy*; D038441:Diet, Mediterranean; D004351:Drug Resistance / Q000187:drug effects; D004730:Endothelium, Vascular / Q000187:drug effects*; D005260:Female; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism*; D006801:Humans; D006943:Hyperglycemia / Q000517:prevention & control*; D007249:Inflammation / Q000188:drug therapy; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000187:drug effects
chemical_list: D001786:Blood Glucose; D052216:Glucagon-Like Peptide 1