Louis , Caroline
[UCL]
Tinant, Gilles
[UCL]
Mignolet, Eric
[UCL]
Thomé, Jean-Pierre
[ULg]
Debier, Cathy
[UCL]
Polychlorinated biphenyls (PCBs) are persistent organic pollutants that biomagnify throughout the food chain. Due to their highly lipophilic character, PCBs are preferentially stored within the adipose tissue. During the mobilization of lipid stores (lactation, fast, diseases and diet), PCBs might be mobilized from the adipocytes into the bloodstream. This release may be problematic because it enables those toxic xenobiotics to reach some target tissues and have negative impacts. PCBs are indeed associated to endocrine disruption, immuno- and neuro-toxicity as well as cancer development. The mechanisms associated with the release of fat-soluble pollutants such as PCBs remain unknown. Several in vivo studies have followed the dynamics of PCBs released from adipose tissue during lipolytic process. However, the complexity of the in vivo situation, which is characterized by a large range of xenobiotics, does not allow understanding precisely the behavior of individual molecules. For example, it is not clearly established yet if PCB congeners, differing by the number and position of chlorine atoms, have their own dynamics of mobilization from adipocytes and are influenced or not by the presence of other congeners. An in vitro model of primary adipocytes was used in order to study the kinetics of mobilization of PCBs during a lipolytic period. Cells were contaminated with an equimolar solution of three PCB congeners (PCB-28, -118, -153) alone or in cocktail. A lipolysis was then induced with a lipolytic medium supplemented with isoproterenol during 12 hours and PCBs were quantified every 3 hours within the cells and the lipolytic medium. Our data indicate that the three PCB congeners were efficiently released from adipocytes and accumulated in the medium during the lipolysis. PCB-153 was released slower from adipocytes than PCB-28 and -118. The high lipophilicity of PCB-153 and the ortho-position of two chlorines atoms could explain this observation. PCB-28 and -118, two mono-ortho congeners, showed similar kinetics of mobilization. These results suggest an impact of the chemical properties of pollutants on their mobilization during periods of negative energy balance. Moreover, the mobilization of PCB congeners, taken individually, did not seem to be influenced by the presence of other congeners within adipocytes. Eventually, it would be interesting to study the potential interactions with other pollutants and investigate different concentrations of cellular contamination to understand the parameters that control the release of lipophilic compounds.
Bibliographic reference |
Louis , Caroline ; Tinant, Gilles ; Mignolet, Eric ; Thomé, Jean-Pierre ; Debier, Cathy. PCB-28, PCB-118 and PCB-153 show different dynamics of mobilization from primary adipocytes during lipolytic process.BelTox Annual Scientific Meeting 2013 (Louvain-la-Neuve, 06/12/2013). |
Permanent URL |
http://hdl.handle.net/2078.1/135353 |