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Homozygosity for the common ACTN3 null polymorphism (ACTN3 577X) results in α-actinin-3 deficiency in ~20% of humans worldwide and is linked to reduced sprint and power performance in both elite athletes and the general population. α-Actinin-3 deficiency is also associated with reduced muscle mass and strength, increased risk of sarcopenia in the elderly, and altered response to muscle wasting induced by denervation and immobilisation. ACTN3 genotype is also a disease modifier for Duchenne muscular dystrophy (DMD), with α-actinin-3 deficiency associated with slower disease progression. Here we show that α-actinin-3 plays a key role in the regulation of protein synthesis and breakdown signalling in skeletal muscle, and its influence on muscle mass begins during early postnatal muscle development. Actn3 genotype also influences the skeletal muscle response to the glucocorticoid dexamethasone. Following acute dexamethasone exposure, transcriptomic analyses by RT-qPCR and RNA-sequencing show reduced atrophy signalling (Mstn, Tmem100, mRas, Fbxo32, Trim63) and anti-inflammatory response in α-actinin-3 deficient mice compared to wild-type. α-Actinin-3 deficiency also protects against muscle wasting following prolonged daily treatment with dexamethasone in female, but not male mice. In combination, these data suggest that ACTN3 R577X is a pharmacogenetic variant influencing the anti-inflammatory and muscle wasting response to glucocorticoid therapy.

OBJECTIVES: The primary aim of this study was to investigate the effects of increased dietary cholesterol intake through the consumption of eggs on ovarian sex hormone and leptin levels in amenorrheic female distance athletes. METHODS: Division I female distance runners classified as amenorrheic (AMEN, n = 5) or eumenorrheic (EUMEN, n = 5) via self-report questionnaire participated in this study. Participants consumed two eggs per day for 12 weeks over the course of the outdoor track and field season. EA was calculated at baseline and post-intervention using 3-day dietary records, triaxial accelerometers, and heart rate (HR) monitors. Maximal oxygen uptake (VO2max) was measured to calculate exercise energy expenditure with training HR data. Serum hormones, body composition, and blood lipids were measured at baseline and post-intervention. RESULTS: There were no differences exhibited by AMEN and EUMEN groups in body composition, EA, or sex hormones after the dietary intervention. Serum leptin increased in the AMEN group by 70% (P = 0.02) from baseline following egg consumption, while no change in serum leptin was observed in the EUMEN group. EA was calculated to be below 30 kcal·kg(−1)·FFM·d(−1) in both groups following intervention. No changes in serum lipids and lipoprotein cholesterol levels were observed in AMEN or EUMEN due to egg consumption. CONCLUSIONS: Twelve-week consumption of two eggs per day increased serum leptin in amenorrheic athletes with low EA with no changes in ovarian sex hormones. The serum lipid profile was not adversely affected by increased dietary cholesterol in the form of eggs. FUNDING SOURCES: Egg Nutrition Center Graduate Fellowship Research Grant.

The purpose of this study was to investigate whether a treadmill endurance exercise program would reduce serum testosterone and leptin in male rats and assess the impact of increased dietary cholesterol on serum hormones. Male Sprague-Dawley Rats (n = 20) were randomly assigned to a control group (C) or an exercise training group (EX) that performed treadmill running 40 min/day, 6 days/week for 12 weeks. At study midpoint (week 6), rats were randomized to a high-cholesterol (HC) diet (n = 10) or remain on standard semi-purified (LC) diet (n = 10). Results are presented as median [IQR]. At end of week 6, EX + LC had significantly lower body weight (508 [460–527] vs 570 [516–606] g; p = 0.01), mean daily energy intake (76.3 [74.9–82.2] vs 90.9 [86.9–94.5] kcal; p

Introduction: AHA guidelines emphasize the importance of limiting pauses during CPR to less than 10 seconds due to the association of interruptions in chest compressions (CC) with adverse outcomes. Previous literature has associated shorter peri-shock pause times with greater odds of survival and longest pause in CC with lower odds of survival, though these analyses were restricted to patients with initial shockable rhythm. The aim of this analysis is to investigate the association between CC pause duration and patient outcomes in all-rhythm OHCA. Methods: OHCA cases from three EMS Agencies in Arizona between Jan 2016-Dec 2016 (n=229) were analyzed. De-identified prehospital patient data were linked to outcome data as part of the state quality program. Pauses calculated from CPR pad accelerometer data were defined by a minimum duration of 1000 ms. Mean pause duration was calculated by case as the average of all pauses, while longest pause duration was defined as the single longest pause in CC. Descriptive statistics and multivariate logistic regression was performed in STATA 15.1. Primary outcome measures defined were ROSC, survival-to-discharge, and favorable neurological outcome (Cerebral Performance Category 1 or 2). Covariates included in the statistical model include time in CPR, age, witnessed arrest, initial shockable rhythm, bystander CPR, and CPR quality. Results: A total of 37.1% of patients (n=85) achieved prehospital ROSC, 12.7% (n=29) survived, and 10.5% (n=24) had favorable neurological outcome. Average mean and longest pause duration was 8.13 + 0.76 s and 24.93 + 2.84 in survivors with favorable neurological outcome compared to 9.21 + 0.47 s and 35.56 + 3.55 s in non-survivors. Mean pause duration was associated with survival (adjusted OR 0.89, 95% CI 0.80-0.99) and favorable neurological outcome (adjusted OR 0.83, 95% CI 0.72-0.97). Longest pause duration was associated with favorable neurological outcome (adjusted OR 0.97, 95% CI 0.94-1.00). Conclusions: Prolonged pauses in CC during prehospital resuscitation was associated with worse survival and neurological function in OHCA patients with all cardiac rhythms. Pause duration should be kept as brief as possible due to the impact upon outcomes regardless of presenting cardiac rhythm.