Oxidized fat induces oxidative stress but has no effect on NF-κB-mediated proinflammatory gene transcription in porcine intestinal epithelial cells

Abstract

The present study suggests that moderate PPARgamma activation and induction of oxidative stress by oxidized frying oil have no implication for NF-kappaB-mediated proinflammatory gene expression in porcine intestinal epithelial cells.

13-hydroxy linoleic acid increases expression of the cholesterol transporters ABCA1, ABCG1 and SR-BI and stimulates apoA-I-dependent cholesterol efflux in RAW264.7 macrophages

“…Interestingly, evidence from feeding studies indeed shows that treatment of rats and guinea pigs with oxidized fat increases HDL cholesterol concentrations in plasma [3,38]. In pigs, however, which are better model objects for humans, no effect of oxidized fat on HDL cholesterol concentrations apoA-I production was found [39]. Epidemiological associations between oxidized fat intake and plasma HDL cholesterol in humans have not been established.…”

Health aspects of oxidized dietary fats

“…Because oxidized fats also contain agonists of PPAR such as oxidized fatty acids (Bull et al, 2003;Grisham et al, 1990), it has been hypothesized that oxidized fats inhibit inflammatory processes through activation of PPAR. This hypothesis, however, could not be verified, although the oxidized fat caused a moderate PPAR activation in the intestinal epithelial cells (Ringseis et al, 2007c). Presumably, the lack of effect of oxidized fat on markers of inflammation is due to an insufficient transrepression of NF-B by the oxidized fat due to the moderate PPAR activation.…”

“…These findings were unexpected because in that study an increased Health aspects of oxidized dietary fats 163 lipid peroxidation and a depletion of antioxidants, both of which are indicative of the induction of oxidative stress, in the intestinal cells were clearly shown (Ringseis et al, 2007c). In addition, reduced activities of antioxidant enzymes in intestinal cells were observed in that study.…”

“…The results of the pig study (Ringseis et al, 2007c) show that markers of inflammation in intestinal epithelial cells were not altered by dietary oxidized fat indicating that oxidized fat does not induce an inflammatory response in the intestine. These findings were unexpected because in that study an increased Health aspects of oxidized dietary fats 163 lipid peroxidation and a depletion of antioxidants, both of which are indicative of the induction of oxidative stress, in the intestinal cells were clearly shown (Ringseis et al, 2007c).…”

“…Although a link between oxidative stress and inflammation has been clearly established (Schreck et al 1991;Sen and Packer, 1996), only one study so far has investigated the effect of oxidized fat on inflammatory processes (Ringseis et al, 2007c). In that study, two groups of pigs were fed two different diets containing either fresh fat or oxidized fat prepared by heating at 200 ëC for 24 h. After 4 weeks on the diets, the pigs were sacrificed and intestinal epithelial cells were isolated and markers of inflammation (NF-B transactivation and NF-B target gene expression) determined.…”