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- Title
Impaired Insulin Signaling in Human Adipocytes After Experimental Sleep Restriction.
- Authors
Broussard, Josiane L.; Ehrmann, David A.; Van Cauter, Eve; Tasali, Esra; Brady, Matthew J.
- Abstract
Background: Insufficient sleep increases the risk for insulin resistance, type 2 diabetes, and obesity, suggesting that sleep restriction may impair peripheral metabolic pathways. Yet, a direct link between sleep restriction and alterations in molecular metabolic pathways in any peripheral human tissue has not been shown. Objective: To determine whether sleep restriction results in reduced insulin sensitivity in subcutaneous fat, a peripheral tissue that plays a pivotal role in energy metabolism and balance. Design: Randomized, 2-period, 2-condition, crossover clinical study. Setting: University of Chicago Clinical Resource Center. Participants: Seven healthy adults (1 woman, 6 men) with a mean age of 23.7 years (SD, 3.8) and mean body mass index of 22.8 kg/m2 (SD, 1.6). Intervention: Four days of 4.5 hours in bed or 8.5 hours in bed under controlled conditions of caloric intake and physical activity. Measurements: Adipocytes collected from subcutaneous fat biopsy samples after normal and restricted sleep conditions were exposed to incremental insulin concentrations. The ability of insulin to increase levels of phosphorylated Akt (pAkt), a crucial step in the insulin-signaling pathway, was assessed. Total Akt (tAkt) served as a loading control. The insulin concentration for the half-maximal stimulation of the pAkt-tAkt ratio was used as a measure of cellular insulin sensitivity. Total body insulin sensitivity was assessed using a frequently sampled intravenous glucose tolerance test. Results: The insulin concentration for the half-maximal pAkt-tAkt response was nearly 3-fold higher (mean, 0.71 nM [SD, 0.27] vs. 0.24 nM [SD, 0.24]; P= 0.01; mean difference, 0.47 nM [SD, 0.33]; P = 0.01), and the total area under the receiver-operating characteristic curve of the pAkt-tAkt response was 30% lower (P = 0.01) during sleep restriction than during normal sleep. A reduction in total body insulin sensitivity (P = 0.02) paralleled this impaired cellular insulin sensitivity. Limitation: This was a single-center study with a small sample size. Conclusion: Sleep restriction results in an insulin-resistant state in human adipocytes. Sleep may be an important regulator of energy metabolism in peripheral tissues. Primary Funding Source: National Institutes of Health.
- Subjects
INSULIN; FAT cells; SLEEP deprivation; TYPE 2 diabetes; CONTROL groups; ENERGY metabolism
- Publication
Annals of Internal Medicine, 2012, Vol 157, Issue 8, p549
- ISSN
0003-4819
- Publication type
Article
- DOI
10.7326/0003-4819-157-8-201210160-00005