Differences in the Expression of the Adenosine A1 Receptor in Adipose Tissue of Obese Black and White Women

Barakat, Hisham A.; Davis, Julianne M.; Lang, David B.; Mustafa, S. Jamal; McConnaughey, Mona M.

doi:10.1210/jc.2005-2109

Cited by 32 publications

(17 citation statements)

References 38 publications

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“…Although several previous studies suggested that AA women exhibit low rates of adipocyte lipolysis that may contribute to their propensity toward obesity ( 11,22 ), our data in postmenopausal women, as well as our previously published study of premenopausal women, show that AA race is not associated with a lower rate of lipolysis. In fact, in postmenopausal women, we fi nd the opposite, higher lipolysis under physiologically relevant conditions (i.e., insulin-or PIA-suppressed).…”

Section: Discussioncontrasting

confidence: 65%

Resistance to the antilipolytic effect of insulin in adipocytes of African-American compared to Caucasian postmenopausal women

Fried

Tittelbach²,

Blumenthal³

et al. 2010

Journal of Lipid Research

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Increased availability of nonesterifi ed fatty acids (FA) contributes to the metabolic dysfunction associated with obesity, including systemic insulin resistance and hyperlipidemia ( 1 ). It is well established that central or upper body obesity, independent of total body fat, is associated with elevated systemic nonesterifi ed FA turnover in premenopausal women. In vivo studies of FA fl uxes show that on a per gram basis, abdominal (Abd) subcutaneous (sc) fat is the main source of the high systemic lipolysis in upper body compared with lower body obese premenopausal women and that leg fat is less lipolytically active ( 1 ). However, microdialysis studies detect no depot difference in lipolysis in nonobese, premenopausal Abd and femoral sc adipose tissue ( 2 ). Nevertheless, both techniques reveal similar responses to the antilipolytic effect of insulin in Abd sc and lower body adipose tissues. In vitro studies also show similar basal lipolytic rates in Abd and gluteal (Glt) or femoral adipocytes of premenopausal women, but Glt adipocytes are more sensitive to insulin ( 3, 4 ). Whether this depot difference exists in postmenopausal women is not known, so this was one of the objectives of the current study.Overweight African-American (AA) women are more hyperinsulinemic and resistant to insulin's glucoregulatory actions than body fat-matched Caucasian (C) women ( 5, 6 ). Thus, it is logical to postulate that AAs may also exhibit higher rates of lipolysis and resistance to the antilipolytic effect of insulin. However, results in the literature on this topic are inconsistent. In premenopausal women, Abstract High fatty acid (FA) fl ux is associated with systemic insulin resistance, and African-American (AA) women tend to be more insulin resistant. We assessed possible depot and race difference in the antilipolytic effect of insulin in adipocytes isolated from abdominal (Abd) and gluteal (Glt) subcutaneous (sc) adipose tissue of overweight, postmenopausal AA and Caucasian (C) women. Percent body fat, fasting insulin, visceral adiposity, and adipocyte size was higher in AA women. Disinhibited lipolysis (presence of adenosine deaminase) per unit adipocyte surface area was similar in Abd and Glt and in AA and C. However, rates of 'basal' [submaximal phenylisopropyl adenosine (PIA) -suppressed] and insulin-suppressed lipolysis were higher in Abd of AA compared with C women even after adjustment for percent fat and visceral fat area. The race difference in rates of PIA-and insulin-suppressed lipolysis in AA were correlated with their hyperinsulinemia, but AA race, independent of fasting insulin, was associated with lower responsiveness (percent suppression) to submaximal insulin concentrations, although sensitivity (ED50) was not affected. Overall, these data are consistent with the hypothesis that decreased responsiveness of Abd adipocytes to antilipolytic effectors may contribute to higher FA availability and thereby to racial differences in insulin resistance. -Fried,

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Section: Discussioncontrasting

confidence: 65%

Resistance to the antilipolytic effect of insulin in adipocytes of African-American compared to Caucasian postmenopausal women

Fried

Tittelbach²,

Blumenthal³

et al. 2010

Journal of Lipid Research

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“…LIPE is an enzyme with lipolytic properties and catalyzes the rate-limiting step of lipolysis by hydrolyzing the stored triacylglycerols and diacylglycerols into fatty acids and glycerol [41]. In our study, LIPE was significantly differentially down-regulated in EAT and MAT compared to SAT.…”

Section: Discussionsupporting

confidence: 47%

The Transcriptome of Human Epicardial, Mediastinal and Subcutaneous Adipose Tissues in Men with Coronary Artery Disease

et al. 2011

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BackgroundThe biological functions of epicardial adipose tissue (EAT) remain largely unknown. However, the proximity of EAT to the coronary arteries suggests a role in the pathogenesis of coronary artery disease (CAD). The objectives of this study were to identify genes differentially regulated among three adipose tissues, namely EAT, mediastinal (MAT) and subcutaneous (SAT) and to study their possible relationships with the development of cardiovascular diseases.Methods and ResultsSamples were collected from subjects undergoing coronary artery bypass grafting surgeries. Gene expression was evaluated in the three adipose depots of six men using the Illumina® HumanWG-6 v3.0 expression BeadChips. Twenty-three and 73 genes were differentially up-regulated in EAT compared to MAT and SAT, respectively. Ninety-four genes were down-regulated in EAT compared to SAT. However, none were significantly down-regulated in EAT compared to MAT. More specifically, the expression of the adenosine A1 receptor (ADORA1), involved in myocardial ischemia, was significantly up-regulated in EAT. Levels of the prostaglandin D2 synthase (PTGDS) gene, recently associated with the progression of atherosclerosis, were significantly different in the three pairwise comparisons (EAT>MAT>SAT). The results of ADORA1 and PTGDS were confirmed by quantitative real-time PCR in 25 independent subjects.ConclusionsOverall, the transcriptional profiles of EAT and MAT were similar compared to the SAT. Despite this similarity, two genes involved in cardiovascular diseases, ADORA1 and PTGDS, were differentially up-regulated in EAT. These results provide insights about the biology of EAT and its potential implication in CAD.

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“…Why this was true for black girls and not white girls is not entirely clear, but may be related to a greater propensity toward overweight, higher rates of sedentary behaviors, 35 or differences in metabolic rate. 36,37 Our findings suggest that meal frequency may be a particularly important variable to consider when designing culturally specific obesity prevention and treatment programs.…”

Section: Discussionmentioning

confidence: 87%

The relationship between meal frequency and body mass index in black and white adolescent girls: more is less

et al. 2007

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Measurements: Three-day food diaries, measured height and weight and self-reported physical activity and television viewing were obtained at annual in-person visits. Results: Over the course of the study, the percentage of girls eating 3 þ meals on all 3 days was reduced by over half (15 vs 6%). Participants who ate 3 þ meals on more days had lower BMI-for-age z-scores. Black girls, but not white girls, who ate 3 þ meals on more days were less likely to meet criteria for overweight. Conclusion: Meal frequency was related to BMI and should be considered when developing guidelines to prevent childhood overweight.

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Differences in the Expression of the Adenosine A1 Receptor in Adipose Tissue of Obese Black and White Women

Abstract: These data suggest that inhibition of lipolysis by adenosine has the potential to be greater in obese AAW, and this could possibly be one explanation for the observation that obese AAW have more difficulty in losing weight than obese CAW.

Cited by 32 publications

References 38 publications

Resistance to the antilipolytic effect of insulin in adipocytes of African-American compared to Caucasian postmenopausal women

Resistance to the antilipolytic effect of insulin in adipocytes of African-American compared to Caucasian postmenopausal women

The Transcriptome of Human Epicardial, Mediastinal and Subcutaneous Adipose Tissues in Men with Coronary Artery Disease

The relationship between meal frequency and body mass index in black and white adolescent girls: more is less

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