Lipophilic Organic Polluants and Morbid Obesity: Kinetic of the Release and Impact on the Metabolic Syndrome Before and After Bariatric Surgery

I- Goals Because of its exponential prevalence and its co-morbidities, obesity, particularly in its most massive forms, has become a public health problem. It is likely that this epidemic be secondary to both genetic and behavioural factors, and also to environmental factors. Specifically, the "obesogen" and "diabetogen" role of several persistant organic polluants (POP) known as endocrine disruptors used in farming or industry has recently been suggested by experimental animal studies and by human epidemiologic studies. Those chemicals are usually lipophilic, are stored in adipose tissue where they bio-accumulate, and are released in the blood stream during the lipolysis that occurs in any weight loss. This weight loss is particularly rapid and important after bariatric surgery, that is proposed as a treatment for morbid obesity usually leading to an improvement of insulin resistance, metabolic syndrome, and diabetes. However, this improvement is not constant, or is less important than would be anticipated for the massive weight loss observed. This raises the question of the importance and of deleterious impact of the blood release of lipophilic POPs on the evolution of metabolic syndrome and the low grade associated inflammation.

In a prospective, multicentric study, we propose to analyse the kinetic of the release of several POPs during rapid and massive weight loss obtained after bariatric surgery. Those POPs have been chosen for their obesogen or diabetogen properties, reported in vitro or in vivo, for their lipophilic nature, and their ubiquitous presence in the home environment and/or into the food chain: bisphenol A (plastics); tributyltin (fungicide, anti-fouling agent or thermic stabilizant); polybrominated diphenyl ethers (PBDE, fire retardants); perchlorated octanoïd acid and its sulphated compounds (PFOA and PFOS, perfluoroalkyls used as surfactant, lubrifiants, and usted in wrappings); and organochorinated compounds such as: PCB153, representing the polychlorinated bisphenyls (electric isolation); hexachlorobenzene (HBC), and several pesticides: DDE, metabolite of DDT, now banned but with a very long half life, hexachlorocyclohexane (HCH), heptachlor, nanochlor and chlordane used in agriculture.

II- Originality and /or new aspect of the project Though suggested by several experimental studies, the role of POP in human obesity remains largely unknown.

There are no or very few papers on the role in humans of the POPs we have selected, but they are supported by animal experimental studies.

The concept of release in the blood stream after weight loss is recent and deserves to be studied.