Adipose tissue composition

In addition, in vivo C MR spectroscopy has been applied to the study of adipose tissue composition in disease. Children with cystic fibrosis were shown to have lower levels of polyunsaturated adipose tissue fatty acids than healthy children, possibly owing to a disorder in essential fatty acid metabolism that may be partly responsible for the development of the disease. Further studies with in vivo MRS in disease have shown a significant increase in saturated adipose tissue fatty acids following transplantation and subsequent weight gain in malnourished patients with liver cirrhosis. It was suggested that this increase in saturated fatty acids may be secondary to a general repletion of membrane polyunsaturated fatty acids or the use of essential fatty acids for biosynthesis of eicosanoids in the postoperative period. 

In an early report of the 1982 annual results of the National Human Adipose Tissue Survey (NHATS), a compound identified as di- -octylphthalate was reportedly detected in 31% of the composite human adipose tissue samples taken in the various regions of the United States that year. Concentrations in lipid ranged from below the level of detection (9 ng/sample) to a maximum of 850 ng/g (EPA 1986d). However, a later report of the 1982 results stated that the chemical detected was not di- -octylphthalate, but was actually diethylhexyl phthalate (EPA 1989b). 

The assumption of a characteristic line pattern for lipids is justified by the fact that IMCL, EMCL, and other adipose tissue in subcutaneous fat tissue or in tibial bone marrow are known to consist mainly of a very similar composition of fatty acid triglycerides. The characteristic line pattern A is indirectly determined by recording a reference lipid spectrum (R) out of a lipid compartment with a relatively homogenous magnetic field described by a normal distribution, i.e., a Gaussian function G. That means R can be written as... 

A further problem is, on what basis should the REE be reported, e.g. per kilogram body weight or per kilogram fat-free mass The former has the disadvantage of being influenced by the body composition, since adipose tissue has a lower metabolic activity than that of the fat-free component of the body. Per kilogram fat-free mass is now preferred because there is a linear increase in the value of the REE with the fat-free mass (Figure 2.4). There is a... 

Table 11.2 Summary of fatty add composition of some adipose tissue depots from human subjects...

Adipose tissue depot Approximate percentage composition ... 

No studies were located regarding the tissue distribution of 1,4-dichlorobenzene in humans after inhalation exposure to 1,4-dichlorobenzene. The compound has been found, however, in human blood, fatty tissue, and breast milk, presumably as a result of exposure via inhalation. In a study of Tokyo residents, detectable levels of 1,4-dichlorobenzene were found in all of 34 adipose tissue samples and all of 16 blood samples tested (Morita and Ohi 1975 Morita et al. 1975). In a national survey of various volatile organic compounds (VOC) found in composites of human adipose tissue, samples were collected from persons living in the nine geographic areas that comprise the United States (within this survey). 

Alterations in the composition of the plasma lipids caused by estrogens are characterized by an increase in the high-density lipoproteins (HDL), a slight reduction in the low-density lipoproteins (LDL), and a reduction in total plasma cholesterol levels. Plasma triglyceride levels are increased. Estrogens decrease hepatic oxidation of adipose tissue lipid to ketones and increase synthesis of triglycerides. 

Caldironi, H.A. and Bazan, N.G. 1982. Effect of antioxidants on malonaldehyde production and fatty acid composition in pieces of bovine muscle and adipose tissue stored fresh and frozen. J. Food Sci. 47 1329-1332, 1337. 

Data on the proportions of different fatty acids in plasma lipid esters (cholesteryl esters, phospholipids, free fatty acids, or triacylglycerol), erythrocyte membranes, or adipose tissue may provide a more objective and accurate path to evaluating dietary fatty acid composition (Arab, 2003 Baylin and Campos, 2006). The fatty acid composition in blood and body tissues reflects the fatty acid composition of the diet at different time points after ingestion. Short and medium-term changes in the composition of dietary fatty acid intake are reflected in plasma lipids and erythrocyte membranes, weeks and months after intake, respectively. The incorporation of fatty acids in adipose tissue reflects long-term changes in the diet (years) (Baylin and Campos, 2006 Katan et al., 1997 Ma et al., 1995 Zock et al, 1997). 

Consequently, a more objective way to measure the habitual intake of milk fat would be the fatty acid composition of adipose tissue. However, this is not routinely performed in larger cohort studies, due to cost and that the procedure is invasive and less tolerated by study participants. Analysis of plasma fatty acid composition is thus a more feasible option for examination to determine dairy intake in the study population. While some groups have separated plasma into its constituent phospholipids and cholesterol esters to analyze serum 15 0 and 17 0 as markers of dairy intake (Smedman et al., 1999), Baylin et al. (2005) found that plasma that was not separated into its constituent cholesteryl ester, phospholipids, and triacylglycerols was still able to reflect habitual dairy intakes comparably to adipose tissue. Thus, whole plasma is an acceptable alternative to fractionated plasma in the absence of adipose tissue for analysis to reflect habitual dairy intakes and may be a cost effective option for consideration when conducting future intervention studies to assess the affect of dairy products on health outcomes. 

The second case-control study from Norway (Biong et ah, 2006) was published in 2006. In this study, 112 myocardial infarction cases and 107 controls were enrolled. Subcutaneous adipose tissue samples were drawn within 4 days of the myocardial infarction and the fatty acid composition of the adipose tissue was analyzed. The study reported that the proportion of 15 0 in adipose tissue was inversely related to the risk of a first myocardial infarction. Also, other fatty acids (14 0, 14 1, and 17 1) associated with the intake of milk fat were inversely related to a first myocardial infarction. Most of these relationships remained (all except between 14 0 and MI) after adjustment for age, sex, waist-to-hip ratio, smoking, and family history of CHD. 

Hodson, L., Skeaff, C. M., and Fielding, B. A. (2008). Fatty acid composition of adipose tissue and blood in humans and its use as a biomarker of dietary intake. Prog. Lipid Res. 47,... 

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