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- Goedecke, Julia H., et al.
(författare)
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Ethnic differences in hepatic and systemic insulin sensitivity and their associated determinants in obese black and white South African women
- 2015
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Ingår i: Diabetologia. - : Springer Science and Business Media LLC. - 0012-186X .- 1432-0428. ; 58:11, s. 2647-2652
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Tidskriftsartikel (refereegranskat)abstract
- Aims/hypothesis There is evidence to suggest that ectopic fat deposition in liver and skeletal muscle may differ between black and white women resulting in organ-specific differences in insulin sensitivity. Accordingly, the aim of the study was to examine ethnic differences in hepatic and peripheral insulin sensitivity, and the association with hepatic and skeletal muscle lipid content, and skeletal muscle gene expression. Methods In a cross-sectional study including 30 obese premenopausal black and white women, body composition (dual energy x-ray absorptiometry), liver fat and skeletal muscle (soleus and tibialis anterior) fat accumulation (proton-magnetic resonance spectroscopy), skeletal muscle gene expression, insulin sensitivity (two-step isotope labelled, hyperinsulinaemic-euglycaemic clamp with 10 mU m(-2) min(-1) and 40 mU m(-2) min(-1) insulin infusions), and serum adipokines were measured. Results We found that, although whole-body insulin sensitivity was not different, obese white women presented with lower hepatic insulin sensitivity than black women (% suppression of endogenous glucose production [% supp EGP], median [interquartile range (IQR)]: 17 [5-51] vs 56 [29-100] %, p = 0.002). While liver fat tended to be lower (p = 0.065) and skeletal muscle fat deposition tended to be higher (p = 0.074) in black compared with white women, associations with insulin sensitivity were only observed in black women (% supp EGP vs liver fat: r = -0.57, p < 0.05 and % supp EGP vs soleus fat: r = -0.56, p < 0.05). Conclusions/interpretation These findings may suggest that black women are more sensitive to the effects of ectopic lipid deposition than white women.
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| 2. |
- Goedecke, Julia H, et al.
(författare)
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Reduced gluteal expression of adipogenic and lipogenic genes in black south african women is associated with obesity-related insulin resistance
- 2011
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Ingår i: Journal of Clinical Endocrinology and Metabolism. - Philadelphia : Lippincott Williams & Wilkins. - 0021-972X .- 1945-7197. ; 96:12, s. E2029-E2033
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Tidskriftsartikel (refereegranskat)abstract
- Context: Black South African women are less insulin sensitive than their White counterparts, despite less central and greater peripheral fat deposition. We hypothesized that this paradox may be explained, in part, by differences in the adipogenic capacity of sc adipose tissue (SAT). Objective: Our objective was to measure adipogenic and lipogenic gene expression in abdominal and gluteal SAT depots and determine their relationships with insulin sensitivity (S(I)) in South African women. Participants and Design: Fourteen normal-weight [body mass index (BMI) <25 kg/m(2)] Black, 13 normal-weight White, 14 obese (BMI >30 kg/m(2)) Black, and 13 obese White premenopausal South African women participated in this cross-sectional study.Main outcomes:S(I) (frequently sampled iv glucose tolerance test) in relation to expression of adipogenic and lipogenic genes in abdominal and gluteal SAT depots. Results: With increasing BMI, Black women had less visceral fat (P = 0.03) and more abdominal (P = 0.017) and gynoid (P = 0.041) SAT but had lower S(I) (P < 0.01) than White women. The expression of adipogenic and lipogenic genes was proportionately lower with obesity in Black but not White women in the gluteal and deep SAT depots (P < 0.05 for ethnicity × BMI effect). In Black women only, the expression of these genes correlated positively with S(I) (all P < 0.05), independently of age and fat mass. Conclusions: Obese Black women have reduced SAT expression of adipogenic and lipogenic genes compared with White women, which associates with reduced S(I). These findings suggest that obesity in Black women impairs SAT adipogenesis and storage, potentially leading to insulin resistance and increased risk of type 2 diabetes.
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| 3. |
- Nankam, Pamela A. Nono, et al.
(författare)
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Changes in systemic and subcutaneous adipose tissue inflammation and oxidative stress in response to exercise training in obese black African women
- 2020
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Ingår i: Journal of Physiology. - : John Wiley & Sons. - 0022-3751 .- 1469-7793. ; 598:3, s. 503-515
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Tidskriftsartikel (refereegranskat)abstract
- Key pointsInflammation and oxidative stress are interrelated during obesity and contribute to the development of insulin resistance; and exercise training represents a key component in the management of these conditions.Black African women, despite high gluteal subcutaneous adipose tissue (SAT) and less visceral fat, are less insulin sensitive than their white counterparts.Exercise training improved systemic oxidative stress in obese black women, which was related to gynoid fat reduction and not insulin sensitivity.Inflammatory markers changed depot‐specifically in response to exercise training, increasing in gluteal SAT without changing in abdominal SAT.The increase of inflammatory state in gluteal SAT after exercise training is suggested to result from tissue remodelling consecutive to the reduction of gynoid fat but does not contribute to the improvement of whole‐body insulin sensitivity in obese black South African women.Inflammation and oxidative stress are interrelated during obesity and contribute to the development of insulin resistance. Exercise training represents a key component in the management of obesity. We evaluated the effects of 12 weeks’ combined resistance and aerobic exercise training on systemic and abdominal vs. gluteal subcutaneous adipose tissue (SAT) inflammatory and oxidative status in obese black South African women. Before and after the intervention, body composition (dual energy X‐ray absorptiometry), cardio‐respiratory fitness (VO2peak), serum and SAT inflammatory and oxidative stress markers were measured from 15 (control group) and 20 (exercise group) women and insulin sensitivity (SI; frequently sampled intravenous glucose tolerance test) was estimated. Following the intervention, VO2peak (9.8%), body fat composition (1–3%) and SI (9%) improved, serum thiobarbituric acid reactive substances (TBARS) decreased (6.5%), and catalase activity increased (23%) in the exercise compared to the control group (P < 0.05), without changes in circulating inflammatory markers. The mRNA content of interleukin‐10, tumour necrosis factor α, nuclear factor κB and macrophage migration inhibitory factor increased in the gluteal SAT exercise compared to the control group P < 0.05), with no changes in abdominal SAT. These changes of inflammatory profile in gluteal SAT, in addition to the reduction of circulating TBARS, correlated with the reduction of gynoid fat, but not with the improvement of SI. The changes in systemic oxidative stress markers and gluteal SAT inflammatory genes correlated with the reduction in gynoid fat but were not directly associated with the exercise‐induced improvements in SI.
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