Portal absorption of 14C after ingestion of spiked milk with 14C-phenanthrene, 14C-benzo[a]pyrene or 14C-TCDD in growing pigs

Abstract

Polycyclic aromatic hydrocarbons (PAHs) and dioxins are lipophilic organic pollutants occurring widely in the terrestrial environment. In order to study the PAHs and 2,3,7,8 TetraChloroDibenzo-pDioxin (TCDD) transfer in the food chain, pigs have been fed with milk mixed either with 14 Cphenanthrene, with 14 C-benzo[a]pyrene or with 14 C-TCDD. The analysis of portal and arterial blood radioactivity showed that both PAHs and TCDD were absorbed with a maximum concentration at 4-6 h after milk ingestion. Then, the blood radioactivity decreased to reach background levels 24 h after milk ingestion. Furthermore, the portal and arterial blood radioactivities were higher for phenanthrene (even if the injected load was the lowest) than these of benzo[a]pyrene or these of TCDD, in agreement with their lipophilicity and water solubility difference. Main 14 C absorption occurred during the 1-3 h time period after ingestion for 14 C-phenanthrene and during the 3-6 h time period for 14 Cbenzo[a]pyrene and for 14 C-TCDD. 14 C portal absorption rate was high for 14 C-phenanthrene (95 %), it was close to 33 % for 14 C-benzo[a]pyrene and very low for 14 C-TCDD (9 %). These results indicate that the three studied molecules have a quite different behaviour during digestion and absorption. Phenanthrene is greatly absorbed and its absorption occurs via the blood system, whereas benzo[a]pyrene and TCDD are partly and weakly absorbed respectively. However these two molecules are mainly absorbed via the portal vein.

Influence of dietary fat type on benzo(a)pyrene [B(a)P] biotransformation in a B(a)P-induced mouse model of colon cancer

“…Using the Caco-2 cell model, Vasiluk et al [65] have demonstrated that uptake of B(a)P released into the gut lumen occurs through passive diffusion and its transfer into the bloodstream is aided by the fugacity gradient generated by the lipids. Additionally, works of Laurent et al [66,67] and Cavret et al [68] have shown a robust relationship between B(a)P and phenanthrene absorption and fat absorption. These studies reinforce the likelihood that prolonged exposure to B(a)P through dietary fat contributes to increased bioavailability of B(a)P and/or its metabolites in the GI tract and cause localized damage to the colon epithelium.…”

Bioavailability and Risk Assessment of Orally Ingested Polycyclic Aromatic Hydrocarbons

“…The above findings suggest that portal venous transport of absorbed DMBA, probably as polar metabolites, is of much greater importance than lymphatic transport. Recent studies by Laurent et al (2002) and Cavret et al (2003) also demonstrated that transfer of labeled B[a]P and phenanthrene in pigs occur through absorption of portal system.…”

Genome-Wide Functional and Stress Response Profiling Reveals Toxic Mechanism and Genes Required for Tolerance to Benzo[a]pyrene in S. cerevisiae

“…It readily distributes to soil and dust particles (Hattemer-Frey and Travis, 1991; Chung et al, 2011). The major routes of exposure are food, both due to endogenous contamination and cooking chemistry, as well as ambient air (indoor and outdoor) where vehicular exhaust and traditional combustion cooking and heating processes are the main source of BaP exposure aside from smoking (Mitchell, 1982; Wester et al, 1990; Laurent et al, 2002; Roseiro et al, 2011). Inhalation is the most effective route of BaP absorption, followed by ingestion, and then dermal uptake; however, the largest exposure is likely by ingestion (Wester et al, 1990; Hattemer-Frey and Travis, 1991; Edoardo, 1992; Laurent et al, 2002; Fromme et al, 2004; Moody et al, 2007).…”