Incorporation of dietary trans monounsaturated fatty acids into tissues of Walker 256 tumor-bearing rats

Abstract

The correlation between dietary trans fatty acids and neoplasia was examined in the present study. Walker 256 tumor-bearing and control rats were fed a trans monounsaturated fatty acid (MUFA)-rich diet for 8 weeks and the incorporation of trans fatty acids by tumor tissue was examined. Also, the effect of tumor growth on trans fatty acid composition of plasma and liver, and the content of thiobarbituric acid-reactive substances (TBARS) was determined. Walker 256 tumor cells presented both trans and cis MUFAs given in the diet. The equivalent diet proportions were 0.66 for trans and 1.14 for cis. Taking into consideration the proportion of trans MUFAs in plasma (11.47%), the tumor incorporated these fatty acids in a more efficient manner (18.27%) than the liver (9.34%). Therefore, the dietary trans fatty acids present in the diet are actively incorporated by the tumor. Tumor growth itself caused marked changes in the proportion of polyunsaturated fatty acids in the plasma and liver but provoked only slight modifications in both trans and cis MUFAs. Tumor growth also reduced the unsaturation index in both plasma and liver, from 97.79 to 86.83 and from 77.51 to 69.64, respectively. This effect was partially related to an increase in the occurrence of the lipid oxidation/peroxidation process of TBARS content which was increased in both plasma (from 0.428 to 0.505) and liver (from 9.425 to 127.792) due to tumor growth.

Influências de dietas ricas em ácidos graxos saturados e insaturados sobre o miocárdio de ratos

“…The mechanism which produced myocardial lesions by increasing fatty acid intake is unknown 7 . It is believed to be from the oxidative stress caused by this type of diet 10,18,19 . Most ingested lipids are incorporated in membrane phospholipids, making them more susceptible to attack from free radicals.…”

“…Most ingested lipids are incorporated in membrane phospholipids, making them more susceptible to attack from free radicals. This mainly occurs with UFA which has unstable molecular bonds in its structure and is therefore more susceptible to oxidative stress 10,18,19 . This hypothesis is supported by our experiment, where oxidative stress and discrete ultrastructural lesions were caused by UFA and SFA rich diets.…”

<a name="home"></a>Effect of unsaturated fatty acids on myocardial performance, metabolism and morphology

“…According to Lamers et al (14), the mechanism by which an imbalance in dietary fatty acids produces myocardial lesions is completely unknown. However, others have suggested that these cardiac morphological injuries can be caused by oxidative stress induced by a diet rich in UFA (24,35,36). In the present study, we observed myocardial oxidative stress and light morphological injuries induced by the UFAenriched chow.…”

“…In the present study, we observed myocardial oxidative stress and light morphological injuries induced by the UFAenriched chow. Increased dietary levels of UFA can cause these lipids to be incorporated into membrane phospholipids, leading to oxidative stress (24,35,36). Although we observed oxidative stress and other recent investigations have established that free radicals may be important contributors to cardiac dysfunction and myocardial damage (13,(37)(38)(39), in the present study myocardial mechanical function was not altered by the diet.…”

Cholesterol changes the fatty acid composition of rat enterocytes

“…The unsaturation index of the fatty acids present in enterocytes was calculated as previously described (15,16). Briefly, the proportion of each fatty acid multiplied by the number of double bonds present in the molecule was summed and the values are presented in Table 1.…”