Chronic Exercise Modifies Age-Related Telomere Dynamics in a Tissue-Specific Fashion

We evaluated the impact of long-term exercise on telomere dynamics in wild-derived short telomere mice (CAST/Ei) over 1 year. We observed significant telomere shortening in liver and cardiac tissues in sedentary 1-year-old mice compared with young (8 weeks) baseline mice that were attenuated in exercised 1-year-old animals. In contrast, skeletal muscle exhibited significant telomere shortening in exercise mice compared with sedentary and young mice. Telomerase enzyme activity was increased in skeletal muscle of exercise compared with sedentary animals but was similar in cardiac and liver tissues. We observed significant age-related decreases in expression of telomere-related genes that were attenuated by exercise in cardiac and skeletal muscle but not liver. Protein content of TRF1 was significantly increased in plantaris muscle with age. In summary, long-term exercise altered telomere dynamics, slowing age-related decreases in telomere length in cardiac and liver tissue but contributing to shortening in exercised skeletal muscle

Plasma ferritin concentration is positively associated with in vivo fatty acid mobilization and insulin resistance in obese women

High rates of fatty acid (FA) mobilization from adipose tissue are associated with insulin resistance (IR) in obesity. In vitro evidence suggests that iron stimulates lipolysis in adipocytes, but whether iron is related to in vivo FA mobilization is unknown. We hypothesized that plasma ferritin concentration ([ferritin]), a marker of body iron stores, would be positively associated with FA mobilization. We measured [ferritin], the rate of appearance of FA in the systemic circulation (FA Ra; stable isotope dilution), key adipose tissue lipolytic proteins and IR (hyperinsulinaemicâ euglycaemic clamp) in 20 obese, premenopausal women. [Ferritin] was correlated with FA Ra (r = 0.65; P = 0.002) and IR (r = 0.57; P = 0.008); these relationships remained significant after controlling for body mass index and plasma [Câ reactive protein] (a marker of systemic inflammation) in multiple regression analyses. We then stratified subjects into tertiles based on [ferritin] to compare subjects with â Highâ ferritinâ versus â Lowâ ferritinâ . Plasma [hepcidin] was more than fivefold greater (P < 0.05) in the Highâ ferritin versus Lowâ ferritin group, but there was no difference in plasma [Câ reactive protein] between groups, indicating that the large difference in plasma [ferritin] reflects a difference in iron stores, not systemic inflammation. We found that FA Ra, adipose protein abundance of hormoneâ sensitive lipase and adipose triglyceride lipase, and IR were significantly greater in subjects with Highâ ferritin versus Lowâ ferritin (all P < 0.05). These data provide the first evidence linking iron and in vivo FA mobilization and suggest that elevated iron stores might contribute to IR in obesity by increasing systemic FA availability.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146491/1/eph12367_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146491/2/eph12367.pd

Pseudonatural Inflation

We study how to obtain a sufficiently flat inflaton potential that is natural from the particle physics point of view. Supersymmetry, which is broken during inflation, cannot protect the potential against non-renormalizable operators violating slow-roll. We are therefore led to consider models based on non-linearly realized symmetries. The basic scenario with a single four-dimensional pseudo Nambu Goldstone boson requires the spontaneous breaking scale to be above the Planck scale, which is beyond the range of validity of the field theory description, so that quantum gravity corrections are not under control. A nice way to obtain consistent models with large field values is to consider simple extensions in extra-dimensional setups. We also consider the minimal structures necessary to obtain purely four-dimensional models with spontaneous breaking scale below M_P; we show that they require an approximate symmetry that is supplemented by either the little-Higgs mechanism or supersymmetry to give trustworthy scenarios.Comment: 30 pages, 2 figures. v2: minor changes, ref. added, accepted for JCA

Scalar perturbation spectra from warm inflation

We present a numerical integration of the cosmological scalar perturbation equations in warm inflation. The initial conditions are provided by a discussion of the thermal fluctuations of an inflaton field and thermal radiation using a combination of thermal field theory and thermodynamics. The perturbation equations include the effects of a damping coefficient $\Gamma$ and a thermodynamic potential $V$. We give an analytic expression for the spectral index of scalar fluctuations in terms of a new slow-roll parameter constructed from $\Gamma$. A series of toy models, inspired by spontaneous symmetry breaking and a known form of the damping coefficient, lead to a spectrum with $n_s>1$ on large scales and $n_s<1$ on small scales.Comment: 12 pages, 5 figures, RevTeX 4, revised with extra figure

Effects of carbohydrate supplementation on variable-intensity exercise responses in boys and men

This study examined the physiological and perceptual effects of carbohydrate (CHO) on variable-intensity exercise (VIE) in boys and men. It was hypothesized that CHO would increase RER in boys and men and that this increase would be greater in boys. Additionally, it was hypothesized that RPE would be attenuated by CHO. Five boys (10-12 years) and seven men (18-30 years) consumed CHO or a placebo (PL) beverage before and throughout VIE. VIE included three 12-min sets of cycling; intensity varied every 20-30 seconds between 25, 50, 75, and 125% VO2max. Boys’ post-exercise glucose was higher in the CHO trial than the PL trial and RER was lower in boys than men, but was not affected by trial. RPE increased over time but was not different between groups or trials. Though VIE responses varied between boys and men, CHO ingestion before and during VIE did not provide physiological or perceptual benefits.Thesis (M.S.)School of Physical Education, Sport, and Exercise Scienc

Short-term exercise training improves flow-mediated dilation and circulating angiogenic cell number in older sedentary adults.

Cardiovascular disease (CVD) risk increases with age due, in part, to impaired endothelial function and decreased circulating angiogenic cell (CAC) number and function. We sought to determine if 10 days of aerobic exercise training improves endothelial function, CAC number and intracellular redox balance in older sedentary adults. METHODS: Eleven healthy subjects (4 men, 7 women), 61 ± 2 yrs of age participated in 60 minutes of aerobic exercise at 70% VO2max for 10 consecutive days while maintaining body weight. Before and after training, endothelial function was measured as flow-mediated dilation of the brachial artery and fasting blood was drawn to enumerate three CAC subtypes. Intracellular ROS and NO in CD34+ CACs were measured using fluorescent probes and reinforced via qPCR. RESULTS: Flow-mediated dilation improved significantly following training (10 ± 1.3% before vs.16 ± 1.4% after training; PThe accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author