Adipose Tissue as a Medium for Epidemiologic Exposure Assessment

Abstract

In the United States, adipose tissue is rarely used as a medium for assessment of prior exposures in epidemiologic studies. Adipose tissue aspirations are in general less invasive and carry less risk than phlebotomy. Tissue samples can be analyzed for a wide number of epidemiologically important exposures. Beyond reflecting long-term energy balance, this tissue offers a relatively stable depot of triglyceride and fat-soluble substances, such as fat-soluble vitamins, and pesticides. As a tissue it represents the greatest reservoir of carotenoids in the body. Halogenated hydrocarbons may be measured in concentrations of hundreds-fold greater than those in blood of the same individuals. The composition of adipose tissue also reflects the long-term dietary intakes of a number of essential fatty acids. The turnover times of all of these substances in adipose tissue remain under-researched. Sampling and storage of adipose tissue, homogeneity of sampling sites, turnover times, and the effects of diet, age, gender, race, hormones, and disease on adipose tissue composition are discussed in this review of current knowledge about adipose tissue stability. Experience in the use of adipose tissue sampling in epidemiologic studies in various countries has shown that it is simple to conduct, requires little training, carries little risk, and does not result in excessive participant refusal. -Environ Health Perspect 103(Suppl 3): 99-106 (1995)

Dietary, supplement, and adipose tissue tocopherol levels in relation to prostate cancer aggressiveness among African and European Americans: The North Carolina-Louisiana Prostate Cancer Project (PCaP)

“…While dietary and supplement use questionnaires can provide estimates of usual intake patterns, typically they reflect intake in the more recent past . On the other hand, fat‐soluble antioxidants are known to selectively accumulate in human adipose tissue and tend to turn over at a low rate . Thus, adipose tissue is a relatively reliable marker of longer‐term tocopherol status.…”

Adipose Tissue as a Site of Toxin Accumulation

“…The lipophilicity of a compound depends on its chemical structure, where bigger, more complex and halogenated compounds are typically more lipophilic and resistant to biodegradation (206). As early as the 1900s, researchers tested for lipophilicity by studying the uptake of nonpolar compounds using organic solvents, like octanol, as a surrogate for the organic matter present in organisms (345).…”

“…For example, the northern elephant seal is a “marine mammal predator” at the top of the food chain that contains massive concentrations of environmental contaminants that are primarily stored in AT (249) (99) (250) (318) (2). Measurements of bioaccumulation in fish and other aquatic organisms is often reported as the bioconcentration factor (BCF), which is defined as the extent to which a chemical concentration in an aquatic organism exceeds the chemical concentration in surrounding water (206). BCFs also correlate with octanol-water partition coefficients (345).…”

Carotenoid intake and adipose tissue carotenoid levels in relation to prostate cancer aggressiveness among African-American and European-American men in the North Carolina-Louisiana prostate cancer project (PCaP)

“…Adipose tissue biomarkers of nutrient intake have been used to assess disease risk and continue to receive increased attention because of the ability of adipose tissue to reflect long‐term nutritional status. However, tissue levels are dependent on factors such as oxidative demand ; thus, the uptake and turnover rates of carotenoids in adipose tissues remain unclear . The suggestion that higher adipose α−carotene and lycopene concentrations are related inversely to CaP aggressiveness warrants further investigation in larger studies, partly because of the possibility that adipose α−carotene and lycopene may have acted as markers for increased consumption of fruits and vegetables or as surrogates for a healthy lifestyle in general.…”