The age-related loss of skeletal muscle mass and function that is associated with sarcopenia can result in ultimate consequences such as decreased quality of life. The causes of sarcopenia are multifactorial and include environmental and biological factors. The purpose of this review is to synthesize what the literature reveals in regards to the cellular regulation of sarcopenia, including impaired muscle regenerative capacity in the aged, and to discuss if physiological stimuli have the potential to slow the loss of myogenic potential that is associated with sarcopenia. In addition, this review article will discuss the effect of aging on Notch and Wnt signaling, and whether physiological stimuli have the ability to restore Notch and Wnt signaling resulting in rejuvenated aged muscle repair. The intention of this summary is to bring awareness to the benefits of consistent physiological stimulus (exercise) to combating sarcopenia as well as proclaiming the usefulness of contraction-induced injury models to studying the effects of local and systemic influences on aged myogenic capability.

Background:Cachexia is a condition characterized as a loss in body mass or metabolic dysfunction and is associated with several prevalent chronic health conditions including many cancers, COPD, HIV, and kidney disease, with between 10 and 50% of patients with these conditions having cachexia. Currently there is little research into cachexia and our objective is to characterize cachexia patients, their healthcare utilization, and associated hospitalization costs. Given the increasing prevalence of chronic diseases, it is important to better understand cachexia so that the condition can be better diagnosed and managed.Methods:We utilized one year (2009) of the Nationwide Inpatient Sample (NIS). The NIS represents all inpatient stays at a random 20% sample of all hospitals within the United States. We grouped cachexia individuals by primary or secondary discharge diagnosis and then compared those with cachexia to all others in terms of length of stay (LOS) and total cost. Finally we looked into factors predicting increased LOS using a negative binomial model.Results:We estimated US prevalence for cachexia-related inpatient admissions at 161,898 cases. Cachexia patients were older, with an average age of 67.95 versus 48.10 years in their non-cachexia peers. Hospitalizations associated with cachexia had an increased LOS compared to non-cachexia patients (6 versus 3 days), with average costs per stay $4641.30 greater. Differences were seen in loss of function (LOF) with cachexia patients, mostly in the major LOF category (52.60%), whereas non-cachexia patients were spread between minor, moderate, and major LOF (36.28%, 36.11%, and 21.26%, respectively). Significant positive predictors of increased LOS among cachexia patients included urban hospital (IRR=1.21, non-teaching urban; IRR=1.23, teaching urban), having either major (IRR=1.41) or extreme (IRR=2.64) LOF, and having a primary diagnosis of pneumonia (IRR=1.15).Conclusion:We have characterized cachexia and seen it associated with increased length of stay, increased cost, and more severe loss of function in patients compared to those without cachexia.

Cachexia increases hospitalization costs and length of stay in several cancer types. Identifying the medical burden associated with cancer cachexia will assist in developing an international consensus for recognition and coding by the medical community and ultimately an effective treatment plans for cancer cachexia.

Unlike the glucocorticoid receptor α (GRα), GR β (GRβ) has a truncated ligand-binding domain that prevents glucocorticoid binding, implicating GRα as the mediator of glucocorticoid-induced skeletal muscle loss. Because GRβ causes glucocorticoid resistance, targeting GRβ may be beneficial in impairing muscle loss as a result of GRα activity. The purpose of this study was to determine how the overexpression of GRβ affects myotube formation and dexamethasone (Dex) responsiveness. We measured GR isoform expression in C2C12 muscle cells in response to Dex and insulin, and through four days of myotube formation. Next, lentiviral-mediated overexpression of GRβ in C2C12 was performed, and these cells were characterized for cell fusion and myotube formation, as well as sensitivity to Dex via the expression of ubiquitin ligases. GRβ overexpression increased mRNA levels of muscle regulatory factors and enhanced proliferation in myoblasts. GRβ overexpressing myotubes had an increased fusion index. Myotubes overexpressing GRβ had lower forkhead box O3 (Foxo3a) mRNA levels and a blunted muscle atrophy F-box/Atrogen-1 (MAFbx) and muscle ring finger 1 (MuRF1) response to Dex. We showed that GRβ may serve as a pharmacological target for skeletal muscle growth and protection from glucocorticoid-induced catabolic signaling. Increasing GRβ levels in skeletal muscle may cause a state of glucocorticoid resistance, stabilizing muscle mass during exposure to high doses of glucocorticoids.

Background: North Carolina Nutrition and Physical Activity Self-Assessment for Child Care (NAP SACC) resources improve child body mass index (BMI) when the resources are introduced by nurses to child care providers, and offered with workshops and incentives. In San Francisco, public health and child care agencies partnered to adapt NAP SACC resources into an annual "Healthy Apple" quality improvement program (HAP). Methods: This cluster randomized controlled trial pilot-tested integration of the HAP with bi-annual public health screenings by nurses. All child care centers that participated in Child Care Health Program (CCHP) screenings in San Francisco in 2011-2012 were offered routine services plus HAP in 2012-2013 (CCHP + HAP, n = 19) or routine services with delayed HAP in 2014-2015 (CCHP + HAP Delayed, n = 24). Intention-to-treat analyses (robust SE or mixed models) used 4 years of screening data from 12 to 17 CCHP + HAP and 17 to 20 CCHP + HAP Delayed centers, regarding 791 to 945 children ages 2 to 5y, annually. Year-specific, child level models tested if children in CCHP + HAP centers had greater relative odds of exposure to 3 index best practices and smaller Autumn-to-Spring changes in BMI percentile and z-score than children in CCHP + HAP Delayed centers, controlling for age, sex, and Autumn status. Multi-year, child care center level models tested if HAP support modified year-to-year changes (2013-2014 and 2014-2015 vs 2011-2012) in child care center annual mean Autumn-to-Spring BMI changes.