Despite the wide range of studies concerning the positive effects of bariatric surgery on metabolic state of morbid obese patient, it is necessary to further investigate the specific role of the "sleeve-gastrectomy" intervention, going not only to research results in terms of safety or efficacy on the treatment of comorbidities, but also aimed to understand whether the improvement of metabolic and cardiovascular parameters is due to total weight loss or rather to visceral fat loss, and how much of this improvement is attributable to changes in inflammatory status. The primary endpoint of the study is to evaluate the effect of sleeve-gastrectomy on metabolic parameters (glyco-lipidic assessment, vitamins), bone-remodelling parameters (vitamin D, parathormone) and cardiovascular parameters (blood pressure, flow-mediated dilation, indexed left ventricular mass, inter-ventricular septum, carotid intima-media thickness) in a large obese population on the basis of total weight loss (TWL), variation of visceral fat area (VFA), variation of peri-renal fat thickness and insulin resistance index ("Homeostasis Model Assessment-insulin resistance" - HOMA). In addition the investigators set themselves the objective of assessing whether the presence of comorbidities (diabetes and hypertension) can influence the effects of the intervention on the above parameters, and whether the levels of the NETs and of adipokines such as chemerin in the pre- and post-intervention can correlate with the metabolic-vascular dysfunction, and play a role in its eventual improvement.

Inclusion Criteria:

- BMI ≥ 40 kg / m2 (or ≥ 35 kg / m2 with at least one comorbidity), aged between 18 and 65 years.

Exclusion Criteria:

• renal or hepatic impairment
• heart failure (New York Heart Association - NYHA II-IV)
• secondary causes of obesity
• major psychiatric disorders

Morbid obese patients with BMI ≥ 40 kg / m2 (or ≥ 35 kg / m2 with at least one comorbidity)