Obesity and Lipids: a Matter of Taste? (HumanFATaste)

The purpose of the protocol is to determine the impact of bariatric surgery on taste receptors and taste perceptions and to precise the factors implicated in taste alterations in 50 obese patients before and 6 months after bariatric surgery (25 Roux Y gastric bypass and 25 sleeve gastrectomy).

Over-consumption high sugar and high fat foods was identified as a main risk factor for obesity. The recent identification of lipid-receptor (CD36, GPR120) in human taste buds suggests that lipids could be perceived not only by their texture and their olfactory characteristics, but also by way of taste. Obese subjects tend to consume more high fat foods than lean subjects. Conversely, bariatric surgery induces behavioral changes limiting the consumption of foods high in sugar and fat. The mechanisms underlying these behavioral changes are not understood. Does obesity is accompanied by a distortion of taste detection of dietary lipids? What are the mechanisms involved? Are they reversible? What could be the effect on food choices and health? This protocol is part of a broader research program that aims to answer these questions by studying the feeding behavior in obese subjects and animals before and after a bariatric surgery. The purpose of the protocol is to determine the impact of bariatric surgery on the expression of taste receptors and taste perceptions and in particular the threshold of perception of fat (and sweet as taste as reference) and to study the association between the changes of taste perceptions and food preferences, amount of weight loss, surgical technique (with or without intestinal bypass), hormonal, metabolic and inflammatory changes, and modification of the oral microbiota. The study will included 50 patients who underwent bariatric surgery, either Roux Y gastric bypass (25 patients) or sleeve gastrectomy (25 patients) that will be explored in the two months before and six months after surgery. These explorations will included a clinical examination with collection of anthropometric data, a body fat determination by impedance, a detailed dietary survey, blood samples for assessment of hormonal parameters (GLP1 , PYY, ghrelin, insulin, leptin) and inflammatory parameters (LPS, TNFalpha, IL-1, IL-6, ...), a tong micro-biopsy to collect taste buds and a sample of oral microbiota and lipids and sugars thresholds determination (linoleic acid or sucrose).

candidates for bariatric surgery by Roux Y gastric bypass with taste assessment and epithelium gustatory smear and biopsy

candidates for bariatric surgery by sleeve gastrectomy with taste assessment and epithelium gustatory smear and biopsy

assessment of taste perceptions and expression of taste receptors before and after bariatric surgery and epithelium gustatory smear and biopsy

To compare the expression of lipid receptors expressed in the taste buds before and after a significant weight loss induced by bariatric surgery

To determine the relationship between taste receptor expression and changes in lipid and sugar perception thresholds before and after surgery

To identify the factors associated with the expression and functionality of taste receptors before and after bariatric surgery: body fat, metabolic, endocrine and inflammatory parameters and peripapillary microbiota.

To compare the effect of RYGBP which bypass the proximal gut with changes in intestinal endocrine secretions and lipid absorption, to that of SG that is a pure restrictive technique without intestinal bypass.

Inclusion Criteria: Affiliation to a health insurance Patients candidates for bariatric surgery based on criteria established by international experts (BMI> 40 or> 35 kg / m² with severe comorbidities, after failure of multidisciplinary care for a period of at least 1 year) Written consent after oral and written informations Exclusion Criteria: Topic guardianship, curatorship or safeguard justice. Taking a treatment known to alter the perception of taste Oral Decay can affect the perception of taste Treatment that may interfere with intestinal peptides or lipids receptors (especially DDP4 inhibitors, anti-inflammatory medications, intestinal lipase inhibitors: Xenical) Tobacco use, alcohol or drugs abuse Known coagulopathy, abnormal hemostasis tests or abnormal platelets count, treatment interfering with coagulation or platelet aggregation Contraindication to bariatric surgery Malignant pathology, severe liver disease or severe inflammatory disease, malabsorption. Pregnancy Positive serology for VIH, VBH and CVH