Validation of the doubly labeled water method using off-axis integrated cavity output spectroscopy and isotope ratio mass spectrometry

This work was supported by an NIH Small Business Innovation (SBIR) research Grant (R44 DK093362), as well as support from the Colorado Nutrition and Obesity Research Center (P30 DK048520) and the Colorado Clinical and Translational Science Institute (UL1 RR025780). Dr. Melanson is also supported by resources from the Geriatric Research, Education, and Clinical Center at the Denver VA Medical Center.Peer reviewedPostprin

Changes in Body Composition and Physical Activity Behavior in a Group of College Freshmen

PURPOSE: To compare: 1-the physiological profile of former athletes (Ath) and non-athletes (Non-Ath) upon college entrance, 2-PA levels in these groups, and 3-changes in physiological profile and PA level of former Ath and Non-Ath and females and males over the course of freshman year. Sixty-two college freshmen were tested during the initial weeks of the school year and again during the final weeks of the school year; the sample consisted of 32 former Ath (18 females and 14 males) and 30 Non-Ath (19 females and 11 males). METHODS: Body composition (BC) was assessed using the Bod Pod with a conversion of body density to body fat percentage (%BF) using the Siri equation. PA was assessed using the International Physical Activity Questionnaire (IPAQ), and 7 days of steps were counted using a pedometer. RESULTS: Upon entrance into college, Ath and Non-Ath had similar BC. Daily average number of steps was similar among the groups (Ath: 11212±2729steps; Non-Ath 11191±3735). However, median MET-minutes of weekly total PA (TPA) was higher in Ath (2737 METmin/wk) than Non-Ath (1613 METmin/wk). Over the course of freshmen year, there was a significantly larger drop in TPA for Ath (-1006±2126 MET-min/wk) than Non-Ath (140±2458 MET-min/wk). Overall, Ath had a higher fat free mass (p=0.046). The overall sample experienced unhealthy changes in BC, with a significant average weight gain of 1.81 kg±2.59 kg and a significant decline in daily steps. Males had a significantly larger decline in steps than females (-2374±3720 steps/day vs. -929±2596 steps/day). The overall sample also had a significant decrease in median TPA (2134 MET-min/wk to 1725 MET-min/wk). However there was a wide variation of changes in BC and PA; some had large changes while others had small or none. CONCLUSION: Generally, there were small but unhealthy changes in BC and decreases in PA during freshman year. Former athletes enter college with initially higher activity level when compared to Non-Ath; however this difference disappears by the end of freshmen year. The key is to determine factors that contribute to the large changes in certain individuals and to pinpoint factors that influence college students’ PA behavior

Data from: Estradiol-mediated improvements in adipose tissue insulin sensitivity are related to the balance of adipose tissue estrogen receptor α and β in postmenopausal women

We recently demonstrated that short-term estradiol (E2) treatment improved insulin-mediated suppression of lipolysis in postmenopausal women, but to a greater extent in those who were late compared to early postmenopausal. In this follow-up study we tested whether subcutaneous adipose tissue (SAT) expression of estrogen receptors (ER) α and β differs between early and late postmenopausal women. We further tested whether the balance of ERα to ERβ in SAT determined the effect of E2 on SAT insulin sensitivity. The present study included 35 women who were ≤6 years past menopause (EPM; n = 16) or ≥10 years past menopause (LPM; n = 19). Fasted SAT samples were taken following 1-week transdermal E2 treatment or placebo (PL) in a random cross-over design. Samples were analyzed for nuclear/cytosolic protein content and mRNA expression using Western blot and qPCR, respectively. While ESR1 increased slightly (~1.4-fold) following E2 treatment in both groups, ERα and ERβ protein expression did not differ between groups at baseline or in response to E2. However, the balance of ERα/ERβ protein in the SAT nuclear fraction increased 10% in EPM compared to a 25% decrease in LPM women (group x treatment interaction, p<0.05). A greater proportion of ERα/ERβ protein in the nuclear fraction of SAT at baseline (placebo day) was associated with greater reduction in SAT insulin resistance (i.e., better suppression of lipolysis, EC50) in response to E2 (r = -0.431, p<0.05). In conclusion, there do not appear to be differences in the proportion of adipose tissue ERα/ERβ protein in late, compared to early, postmenopausal women. However, the balance of ERα/ERβ may be important for E2-mediated improvement in adipose tissue insulin sensitivity

Estradiol-mediated improvements in adipose tissue insulin sensitivity are related to the balance of adipose tissue estrogen receptor α and β in postmenopausal women

<div><p>We recently demonstrated that short-term estradiol (E₂) treatment improved insulin-mediated suppression of lipolysis in postmenopausal women, but to a greater extent in those who were late compared to early postmenopausal. In this follow-up study we tested whether subcutaneous adipose tissue (SAT) expression of estrogen receptors (ER) α and β differs between early and late postmenopausal women. We further tested whether the balance of ERα to ERβ in SAT determined the effect of E₂ on SAT insulin sensitivity. The present study included 35 women who were ≤6 years past menopause (EPM; n = 16) or ≥10 years past menopause (LPM; n = 19). Fasted SAT samples were taken following 1-week transdermal E₂ treatment or placebo (PL) in a random cross-over design. Samples were analyzed for nuclear/cytosolic protein content and mRNA expression using Western blot and qPCR, respectively. While ESR1 increased slightly (~1.4-fold) following E₂ treatment in both groups, ERα and ERβ protein expression did not differ between groups at baseline or in response to E₂. However, the balance of ERα/ERβ protein in the SAT nuclear fraction increased 10% in EPM compared to a 25% decrease in LPM women (group x treatment interaction, <i>p</i><0.05). A greater proportion of ERα/ERβ protein in the nuclear fraction of SAT at baseline (placebo day) was associated with greater reduction in SAT insulin resistance (i.e., better suppression of lipolysis, EC₅₀) in response to E₂ (r = -0.431, <i>p</i><0.05). In conclusion, there do not appear to be differences in the proportion of adipose tissue ERα/ERβ protein in late, compared to early, postmenopausal women. However, the balance of ERα/ERβ may be important for E₂-mediated improvement in adipose tissue insulin sensitivity.</p><p><b>Trial Registration: Clinical Trials#:</b><a href="https://clinicaltrials.gov/ct2/show/NCT01605071" target="_blank">NCT01605071</a></p></div