Linoleic acid in adipose tissue

Glaser, K.R., Scheeder, M.R.L., and Wenk, C. 2000. Dietary Cl8 1 trans fatty acids increase conjugated linoleic acid in adipose tissue of pigs. Euro. J. Lipid Sci. Technol. 102, 684—686. 

Smit, L.A., Baylin, A, Campos, H. 2010. Conjugated linoleic acid in adipose tissue and risk of myocardial infarction. American Journal of Clinical Nutrition 92, 34—40. 

A case-control study of sudden cardiac death found that higher concentrations of trans isomers of linoleic acid in adipose tissue, compared with lower concentrations, were associated with increased risk of sudden death. After controlling for smoking and making an allowance for social class, this relationship became insignificant. 

It is not certain that the presence of CLA in tissue lipids is due entirely to the production of cis-9, trans-11 as an intermediate during the biohydrogenation of linoleic acid in the rumen. However, the amount of CLA in milk (7 J) and butter (14) is positively correlated to the level of dietary linoleic acid. Some long chain fatty acid intermediates reach the small intestine and are normally absorbed and deposited into adipose tissue (75). There is seasonal variation in CLA content of milk, with the highest values occurring usually in summer (76). 

Ide, T. 2005. Interaction of fish oil and conjugated linoleic acid in affecting hepatic activity of lipogenic enzymes and gene expression in liver and adipose tissue. Diabetes, 54,412-423. 

A consequence of the slower growth that yields a leaner carcase is a relatively more unsaturated fatty acid composition in adipose tissue (in particular a higher proportion of linoleic acid) and therefore... 

Tsuneishi, E., Matsuzaki, M., Shiba, N., and Hara, S.I. (1999) Conjugated Linoleic Acid Concentrations in Adipose Tissues of Japanese Black Fattening Steers, Anim. Sci. J. 70, 547-550. 

Jiang, J., Wolk, A., and Vessby, B. (1999) Relation Between the Intake of Milk Fat and the Occurrence of Conjugated Linoleic Acid in Human Adipose Tissue, Am. J. Clin. Nutr. 70, 21-27. 

Epidemiological data on human populations show a strong positive correlation between age-adjusted mortality from breast cancer and dietary fat intake in different countries of the world (Carroll Khor, 1975 Carroll, 1975) but, as in the experiments with animals, there does not seem to be a correlation with intake of essential fatty acids. More detailed analysis of the data showed a positive correlation with intake of animal fat, but little or no correlation with intake of vegetal fat (Carroll, 1975). Moreover, although breast cancer mortality is about 5 times as hi in Americans as in Japanese, the per capita intake of linoleic acid is reported to be about the same in both countries (Insull et al, 1969). In addition, an analysis of the fatty acid composition of adipose tissue showed a level of 16.5% linoleic acid in Japanese compared to 10.2% in Americans (Insull et al, 1969). 

Linoleic acid (3-7) is the most common polyenoic fatty add. It is present, at least in traces, in aU fats. For example, sunflower and soybean oils usually contain 50-60% of linoleic add safflower oil contains 75% linoleic acid. In the fat of animals, where this essential fatty add gets from plant food, its content is typically 15-25%, but maybe higher (cardioUpin of heart muscle contains 75% linoleic acid). Linolenic acid (3-11) is the main component of leaves, especially in the photosynthesising apparatus of algae and higher plants. Linolenic acid is present in linseed oil in amounts of up to 65%. Soybean and rapeseed oils only contain up to 10% linolenic acid. In animal tissues, it is usually a minor component (up to 1%), although the adipose tissue of horses contains up to 10% of this essential fatty acid. 

The measurements of the total amount of various essential fatty acids as co-3 fatty acids in plasma, serum, or erythrocyte membrane phospholipids have been indicated as useful markers of essential polyunsaturated fatty adds. Essential fatty acid deficiency is a clinical condition that derives from inadequate status of co-3 and co-6 fatty acids however, the symptoms are nonspecific and may not present prior to marginal essential fatty acid status. Widely used biomarkers for bicx hemi( essai-tial fatty acid deficiency are mead acid and the triene/tetraene ratio. Howcvct, the total plasma triene/tetraene ratio has been considered the gold standard for essential fatty acid deficiency. Mead acid, or 5,8,11-eicosatrienoic acid (5,8,11-20 3 co-9) is synthesized from endogenous oleic acid and is increased when there is insufficient concentrations of linoleic and a-linolenic acid to meet the needs of polyunsaturated fatty acids. Under normal conditions only trace amounts of mead acid are found in plasma. EPA and DHA inhibit mead acid synthesis. Mead acid measurement is an indicator of essential fatty acid deficiency state, while essential fatty add depletion is associated with a decrease in plasma hnoleate and arachidonate percentages. Assessment of long-term essential fatty acid intake is measured in adipose tissue, and it is considered the best indicator because of its slow tumover. - Cutoff values for the assessment of essential fatty adds and to-3 fatty acid status in erythrocytes have been reported. Proposed cutoff values for children older than 0.2 years are 0.46 mol% 20 3 co-9 (mead acid) for early suspicion of essential fatty acid defidency, 0.068 mol/mol docosapentaenoic/arachidonic acid... 

Studies carried out in our laboratory (Raulin et al.,1974) nevertheless suggest the need to look for other explanations which might explain the indispensable character of linoleic acid. The as yet unexplained increase in vivo in nuclear and mitochondrial DNA polymerase activity which was seen in adipose tissue enriched for linoleic acid (Launay et al., 1968,1969) has encouraged us to study the role of metabolic products of the EFAs in certain fundamental reactions of intermediary metabolism, other than that involving lipid components. ... 

In human adipose tissue, palmitoyl-CoA is usually used in the first glycerol-3-phosphate acylation reaction. The next two acyl residues are normally unsaturated fatty acids oleic acid and, less commonly, linoleic acid. Triglyceride biosynthesis is stimulated by insulin, most likely via its activation of lipoprotein lipase and its activity in moving glucose into the cells. 

Chajes, V., Lavillonniere, F., Maillard, V., Giraudeau, B., Jourdan, M.L., Sebedio, J.-L., Bougnoux, P. 2003. Conjugated linoleic acid content in breast adipose tissue of breast cancer patients and the risk of metastasis. Nutr. Cancer. 45, 17-23. 

Yurawecz, M.P., Roach, J.A.G., Sehat, N., Mossoba, M.M., Kramer, J.K.G., Fritsche, J., Steinhart, H., Ku, Y. 1998. A new conjugated linoleic acid isomer, 7 trans, 9 m-octadcca-dienoic acid, in cow milk, cheese, beef and human milk and adipose tissue. Lipids. 33, 803-809. 

Rieserus, U., Berglund, L., and Vessby, B. 2001. Conjugated linoleic acid (CLA) reduced abdominal adipose tissue in obese middle-aged men with signs of metabohc syndrome, a randomized controlled trial. Int. J. Obesity, 25,1129-1135. 

Tsuboyama-Kasaoka, N., Takahashi, M., Tanemura, K., Kim, H. J., Tnage, T., Okuyama, H., Kasai, M., Ikemoto, S., and Ezaki, O. 2000. Conjugated linoleic acid supplementation reduces adipose tissue by apoptosis and develops lipodystrophy in mice. Diabetes, 49,1534-1542. 

In EFA deficiency, oleic acid can be dehydrogenated to yield polyunsaturated fatty acids (PUFAs) that are nonessential and do not substitute for the essential fatty acids. One suchPUFA is 5,8,11-eicosatrienoic acid, which occurs in significant amounts in heart, liver, adipose tissue, and erythrocytes of animals fed diets deficient in EFAs but decreases after supplementation with linoleic or linolenic acids. Its appearance in tissues and plasma has been used in the assessment of EFA deficiency. 

Chen Z-Y. Menard CR, Cunnane SC. Weight cycling progressively depletes carcass and adipose tissue linoleic acid and a-linolenic acid in young rats. Br J Nutr 1996 75 583. 

Lin and Homing [341,363] carried out comparative investigations of serum long-chain acids (in both free and bound state) of patients during the post-stroke period versus normal individuals a marked decrease in the linoleic/oleic acid ratio was observed for the stroke patients. As capillary GC becomes a widely accepted routine method, its use for rapid screening of various disorders of the lipid metabolism will become more obvious to a number of clinical laboratories. Some progress in this direction has already been indicated [366-368]. As reported by Haan et al. [368], screening of up to SO samples a day for FA from serum and adipose tissue biopsies is entirely feasible. 

Sexton, P.T., Sinclair, A.J., O Dea, K., Sanigorski, A., and Walsh, J. (1995) The Relationship Between Linoleic Acid Level in Serum, Heart and Adipose Tissue in Humans, Asia Pacific J. Clin. Nutr. 4, 314—318. 

Fig.l. Effects of triacylglycerol (TAG)-conjugated linoleic acid (CLA) and free fatty acid (FFA)-CLA on abdominal adipose tissue weights in OLETF rats. Rats were fed control diet (LA) or CLA diets (1 % TAG-CLA or FFA-CLA) for 4 wk. LETO lean rats were fed control diet. Values with different letters are significantly different, P< 0.05. 

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