Cardiorespiratory Fitness Is Impaired in Type 1 and Type 2 Diabetes: A Systematic Review, Meta-Analysis, and Meta-Regression.

INTRODUCTION: Low cardiorespiratory fitness (CRF) increases the risk of cardiovascular disease by up to 8-fold, and is one of the strongest predictors of mortality. Some studies demonstrate impaired CRF in people living with type 1 and type 2 diabetes compared to those without diabetes, while others demonstrate no diabetes-associated impairment in CRF. PURPOSE: We aimed to determine whether diabetes can influence CRF, and if so, identify clinical associations underlying diabetes-associated exercise impairments. METHODS: 68 studies were included in the quantitative analysis. Standardized mean difference (SMD) was calculated and meta-analyses and meta-regressions were performed by using a random-effects model. RESULTS: Diabetes is associated with a large negative effect on CRF (SMD = -0.80; p < 0.001)- an effect that is partially mitigated, but still significant, in those with high physical activity levels (SMD = -0.50; p = 0.007). A sedentary lifestyle (SMD = -0.83; p = 0.007), and the presence of clinical complications related to diabetes (SMD = -1.66; p < 0.001) predict a greater magnitude of CRF reduction in people with diabetes compared to controls without diabetes. Both type 1 and type 2 diabetes are independently associated with impaired CRF compared to controls without diabetes; however, the effect is significantly greater in those type 2 diabetes (SMD = -0.97; p < 0.001). Meta-regression analysis demonstrates the effects of diabetes on CRF are primarily associated with HbA1c levels for type 1 diabetes (B = -0.07; p < 0.001) and body mass index for type 2 diabetes (B = -0.17; p = 0.005). CONCLUSIONS: These data demonstrate a negative influence of diabetes on the key risk factor of low CRF and provide critical insight into specific clinical markers of low CRF associated with diabetes.

Low Response to Aerobic Training in Metabolic Disease: Role of Skeletal Muscle.

Aerobic exercise is established to increase cardiorespiratory fitness (CRF), which is linked to reduced morbidity and mortality. However, people with metabolic diseases such as type 1 and type 2 diabetes may be more likely to display blunted improvements in CRF with training. Here, we present evidence supporting the hypothesis that altered skeletal muscle signaling and remodeling may contribute to low CRF with metabolic disease.

ROAR ED-SANE: A Retrospective Observational Assessment Review of an Emergency Department Sexual Assault Nurse Examiner Program's Adherence to Centers for Disease Control and Prevention Guidelines for Sexually Transmitted Infections.

BACKGROUND: Sexual assault survivors are at increased risk for sexually transmitted infections. Sexual Assault Nurse Examiner programs guide sexually transmitted infection treatment, monitoring, and follow-up scheduling according to guidelines by the Centers for Disease Control and Prevention (CDC). Reported low rates of provider adherence to CDC treatment guidelines and patient adherence to follow-up necessitate a review of medication prescribing and follow-up scheduling practices, especially at smaller community hospitals in the United States. METHODS: A retrospective medical record review was conducted to assess adherence rates to CDC guidelines for prescribing practices, scheduling, and follow-up of sexual assault survivors. We included pediatric and adult patients presenting to the emergency department (ED) and participating in the ED Sexual Assault Nurse Examiner program at a rural, community-based teaching hospital in La Crosse, WI, from January 2018 to December 2021. Descriptive statistics were used to evaluate results. RESULTS: Analysis included 103 patients. Prescribing adherence to CDC guidelines was >80% for all except human immunodeficiency virus (53.4%), trichomoniasis (68.1%), and hepatitis B (69%). Of the 38 patients who had a follow-up scheduled during their ED encounter, 78.9% attended their scheduled follow-up and 94.7% of those appointments were scheduled within the CDC-recommended time frame, leading to an overall adherence of 40%. CONCLUSIONS: Adherence rates were high for most prescribing practices, and attendance of scheduled follow-up was higher than expected. Opportunities to improved adherence to CDC guidelines were identified in prescribing for 3 disease states (human immunodeficiency virus, trichomoniasis, and hepatitis B) and in scheduling of follow-up.

Pharmacist adjustment of preoperative antibiotic orders to the preferred preoperative antibiotic cefazolin for patients with penicillin allergy labeling.

PURPOSE: Emerging literature has detailed the safe use of cefazolin in patients with immunoglobulin E-mediated penicillin allergy labeling (PAL) such as hives and anaphylaxis. The purpose of this article is to detail efforts led by an antimicrobial stewardship pharmacist working with an interdisciplinary team to optimize preoperative antimicrobials in patients with PAL. METHODS: A pharmacist-led, interdisciplinary collaborative practice agreement (CPA) was activated in January 2020 to permit pharmacists to independently optimize preoperative antibiotics to the preferred cefazolin in patients with PAL if nonsevere or severe reactions had been reported. A patient registry was established covering the timeframe between January 8, 2020, and January 6, 2022. Reaction during surgery was assessed via 2-provider documentation, which included surgeon and anesthesiology staff documentation of any complications during the procedure related to a suspected allergic safety event. Utilization of cefazolin, clindamycin, and vancomycin for preoperative prophylaxis was monitored before and after implementation of the CPA. RESULTS: During the stated timeframe, 10,182 procedures and/or surgeries were completed on 1,572 (15.4%) patients with PAL and 659 (41.9%) patients previously reporting at least one reaction categorized as a severe reaction, which was hives for 71.2% of these patients. Of the 659 patients with PAL reporting a severe reaction, 356 received a preoperative cephalosporin (cefazolin, 98.8%; ceftriaxone, 1.2%) and tolerated it without a reported safety event, including 52 patients with PAL previously reporting anaphylaxis. An increase in preferred preoperative antimicrobial prophylaxis utilization was noted (cefazolin: 86% to 96.3%, P < 0.001; 2019 to 2021) with reductions noted in the use of nonpreferred preoperative antibiotics (clindamycin: 2.1% to 0.2%, P < 0.001; vancomycin: 3.2% to 0.4%, P < 0.001; 2019 to 2021). CONCLUSION: A pharmacist-led, interdisciplinary CPA increased preferred preoperative antimicrobial use in patients with PAL reporting severe allergic reactions, including hives and anaphylaxis, without reported safety events.

Canagliflozin Prevents Hyperglycemia-Associated Muscle Extracellular Matrix Accumulation and Improves the Adaptive Response to Aerobic Exercise.

Chronic hyperglycemia is associated with low response to aerobic exercise training in rodent models and humans, including reduced aerobic exercise capacity and impaired oxidative remodeling in skeletal muscle. Here, we investigated whether glucose lowering with the sodium-glucose cotransporter 2 inhibitor (SGLT2i), canagliflozin (Cana; 30 mg/kg/day), could restore exercise training response in a model of hyperglycemia (low-dose streptozotocin [STZ]). Cana effectively prevented increased blood glucose in STZ-treated mice. After 6 weeks of voluntary wheel running, Cana-treated mice displayed improvements in aerobic exercise capacity, higher capillary density in striated muscle, and a more oxidative fiber-type in skeletal muscle. In contrast, these responses were blunted or absent in STZ-treated mice. Recent work implicates glucose-induced accumulation of skeletal muscle extracellular matrix (ECM) and hyperactivation of c-Jun N-terminal kinase (JNK)/SMAD2 mechanical signaling as potential mechanisms underlying poor exercise response. In line with this, muscle ECM accretion was prevented by Cana in STZ-treated mice. JNK/SMAD2 signaling with acute exercise was twofold higher in STZ compared with control but was normalized by Cana. In human participants, ECM accumulation was associated with increased JNK signaling, low VO2peak, and impaired metabolic health (oral glucose tolerance test-derived insulin sensitivity). These data demonstrate that hyperglycemia-associated impairments in exercise adaptation can be ameliorated by cotherapy with SGLT2i.

Effect of short-term hindlimb immobilization on skeletal muscle atrophy and the transcriptome in a low compared with high responder to endurance training model.

Skeletal muscle atrophy is a physiological response to disuse, aging, and disease. We compared changes in muscle mass and the transcriptome profile after short-term immobilization in a divergent model of high and low responders to endurance training to identify biological processes associated with the early atrophy response. Female rats selectively bred for high response to endurance training (HRT) and low response to endurance training (LRT; n = 6/group; generation 19) underwent 3 day hindlimb cast immobilization to compare atrophy of plantaris and soleus muscles with line-matched controls (n = 6/group). RNA sequencing was utilized to identify Gene Ontology Biological Processes with differential gene set enrichment. Aerobic training performed prior to the intervention showed HRT improved running distance (+60.6 ± 29.6%), while LRT were unchanged (-0.3 ± 13.3%). Soleus atrophy was greater in LRT vs. HRT (-9.0 ±8.8 vs. 6.2 ±8.2%; P<0.05) and there was a similar trend in plantaris (-16.4 ±5.6% vs. -8.5 ±7.4%; P = 0.064). A total of 140 and 118 biological processes were differentially enriched in plantaris and soleus muscles, respectively. Soleus muscle exhibited divergent LRT and HRT responses in processes including autophagy and immune response. In plantaris, processes associated with protein ubiquitination, as well as the atrogenes (Trim63 and Fbxo32), were more positively enriched in LRT. Overall, LRT demonstrate exacerbated atrophy compared to HRT, associated with differential gene enrichments of biological processes. This indicates that genetic factors that result in divergent adaptations to endurance exercise, may also regulate biological processes associated with short-term muscle unloading.

Effect of Pharmacist Audit on Antibiotic Duration for Pneumonia and Urinary Tract Infection.

OBJECTIVE: To assess the effect of clinical pharmacists in daily audits, under the direction of an antimicrobial stewardship program, of antibiotic treatment durations for the common inpatient disease states of community-acquired pneumonia (CAP) and urinary tract infection (UTI). PATIENTS AND METHODS: This was a retrospective single-center cohort study that evaluated the difference in the duration of antibiotic therapy for CAP or non-catheter-associated UTI of hospitalized patients who received a daily audit by clinical pharmacists compared with patients who did not receive a daily audit. Retrospective chart review included randomly selected hospitalized patients diagnosed with CAP or UTI during preaudit and postaudit periods. RESULTS: The preaudit group had 64 patients; and the postaudit group, 51 patients. The therapy duration was 7 days in the preaudit group and 6 days in the postaudit group (P=.55). Fluoroquinolone use was reduced in the postaudit group and was significantly less than in the preaudit group (24 [37.5%] vs 7 [13.7%]; P=.007). CONCLUSION: The daily audits of clinical pharmacists may be an effective method to reduce the duration of antibiotic therapy and are effective in the reduction of fluoroquinolone use. Additional studies must be done to further investigate the effects of clinical pharmacist antimicrobial stewardship efforts.

A Framework for Outpatient Infusion of Antispike Monoclonal Antibodies to High-Risk Patients with Mild-to-Moderate Coronavirus Disease-19: The Mayo Clinic Model.

The administration of spike monoclonal antibody treatment to patients with mild to moderate COVID-19 is very challenging. This article summarizes essential components and processes in establishing an effective spike monoclonal antibody infusion program. Rapid identification of a dedicated physical infrastructure was essential to circumvent the logistical challenges of caring for infectious patients while maintaining compliance with regulations and ensuring the safety of our personnel and other patients. Our partnerships and collaborations among multiple different specialties and disciplines enabled contributions from personnel with specific expertise in medicine, nursing, pharmacy, infection prevention and control, electronic health record (EHR) informatics, compliance, legal, medical ethics, engineering, administration, and other critical areas. Clear communication and a culture in which all roles are welcomed at the planning and operational tables are critical to the rapid development and refinement needed to adapt and thrive in providing this time-sensitive beneficial therapy. Our partnerships with leaders and providers outside our institutions, including those who care for underserved populations, have promoted equity in the access of monoclonal antibodies in our regions. Strong support from institutional leadership facilitated expedited action when needed, from a physical, personnel, and system infrastructure standpoint. Our ongoing real-time assessment and monitoring of our clinical program allowed us to improve and optimize our processes to ensure that the needs of our patients with COVID-19 in the outpatient setting are met.

The MicroRNA miR-696 is regulated by SNARK and reduces mitochondrial activity in mouse skeletal muscle through Pgc1α inhibition.

OBJECTIVE: MicroRNAs (miRNA) are known to regulate the expression of genes involved in several physiological processes including metabolism, mitochondrial biogenesis, proliferation, differentiation, and cell death. METHODS: Using "in silico" analyses, we identified 219 unique miRNAs that potentially bind to the 3'UTR region of a critical mitochondrial regulator, the peroxisome proliferator-activated receptor gamma coactivator (PGC) 1 alpha (Pgc1α). Of the 219 candidate miRNAs, miR-696 had one of the highest interactions at the 3'UTR of Pgc1α, suggesting that miR-696 may be involved in the regulation of Pgc1α. RESULTS: Consistent with this hypothesis, we found that miR-696 was highly expressed in the skeletal muscle of STZ-induced diabetic mice and chronic high-fat-fed mice. C2C12 muscle cells exposed to palmitic acid also exhibited a higher expression of miR-696. This increased expression corresponded with a reduced expression of oxidative metabolism genes and reduced mitochondrial respiration. Importantly, reducing miR-696 reversed decreases in mitochondrial activity in response to palmitic acid. Using C2C12 cells treated with the AMP-activated protein kinase (AMPK) activator AICAR and skeletal muscle from AMPKα2 dominant-negative (DN) mice, we found that the signaling mechanism regulating miR-696 did not involve AMPK. In contrast, overexpression of SNF1-AMPK-related kinase (SNARK) in C2C12 cells increased miR-696 transcription while knockdown of SNARK significantly decreased miR-696. Moreover, muscle-specific transgenic mice overexpressing SNARK exhibited a lower expression of Pgc1α, elevated levels of miR-696, and reduced amounts of spontaneous activity. CONCLUSIONS: Our findings demonstrate that metabolic stress increases miR-696 expression in skeletal muscle cells, which in turn inhibits Pgc1α, reducing mitochondrial function. SNARK plays a role in this process as a metabolic stress signaling molecule inducing the expression of miR-696.

Low responders to endurance training exhibit impaired hypertrophy and divergent biological process responses in rat skeletal muscle.

NEW FINDINGS: What is the central question of this study? The extent to which genetics determines adaptation to endurance versus resistance exercise is unclear. Previously, a divergent selective breeding rat model showed that genetic factors play a major role in the response to aerobic training. Here, we asked: do genetic factors that underpin poor adaptation to endurance training affect adaptation to functional overload? What is the main finding and its importance? Our data show that heritable factors in low responders to endurance training generated differential gene expression that was associated with impaired skeletal muscle hypertrophy. A maladaptive genotype to endurance exercise appears to dysregulate biological processes responsible for mediating exercise adaptation, irrespective of the mode of contraction stimulus. ABSTRACT: Divergent skeletal muscle phenotypes result from chronic resistance-type versus endurance-type contraction, reflecting the principle of training specificity. Our aim was to determine whether there is a common set of genetic factors that influence skeletal muscle adaptation to divergent contractile stimuli. Female rats were obtained from a genetically heterogeneous rat population and were selectively bred from high responders to endurance training (HRT) or low responders to endurance training (LRT; n = 6/group; generation 19). Both groups underwent 14 days of synergist ablation to induce functional overload of the plantaris muscle before comparison to non-overloaded controls of the same phenotype. RNA sequencing was performed to identify Gene Ontology biological processes with differential (LRT vs. HRT) gene set enrichment. We found that running distance, determined in advance of synergist ablation, increased in response to aerobic training in HRT but not LRT (65 ± 26 vs. -6 ± 18%, mean ± SD, P < 0.0001). The hypertrophy response to functional overload was attenuated in LRT versus HRT (20.1 ± 5.6 vs. 41.6 ± 16.1%, P = 0.015). Between-group differences were observed in the magnitude of response of 96 upregulated and 101 downregulated pathways. A further 27 pathways showed contrasting upregulation or downregulation in LRT versus HRT in response to functional overload. In conclusion, low responders to aerobic endurance training were also low responders for compensatory hypertrophy, and attenuated hypertrophy was associated with differential gene set regulation. Our findings suggest that genetic factors that underpin aerobic training maladaptation might also dysregulate the transcriptional regulation of biological processes that contribute to adaptation to mechanical overload.

The impact of narratives and active video games on long-term moderate-to-vigorous physical activity: A randomized controlled trial protocol.

BACKGROUND: Although physical activity (PA) has been shown in helping prevent and treat obesity, current PA interventions are still not effective in ameliorating the obesity epidemic. Additional forms of PA need to be investigated to improve PA engagement and outcomes. We hypothesize that pairing a narrative (i.e., story) with an active video game (AVG), a less traditional form of PA, will increase participant engagement in PA. This paper presents the rationale, implementation, and pilot results of a study assessing the effect of narrative's impact on PA and a series of other health outcomes. OBJECTIVE: This paper presents the rationale, implementation, and pilot results of a study assessing the effect of narrative's impact on PA and a series of other health outcomes. METHODS/DESIGN: The Active Video Game Study is a six-month randomized controlled single-blind trial projected to include 210 participants. The intervention strategy will pair a narrative to an active video game (AVG). Participants will be randomized into 3 groups: condition A [Narrative + AVG], condition B [AVG Only], and condition C [Control]. Participants will undergo three in-person data collection visits over the course of six months. Inclusion criteria are that children are between the ages of 8-12 and have a BMI ≥ 85%. The primary outcome is change in moderate to vigorous physical activity (MVPA). Secondary outcome measures include change in BMI percentile, fasting insulin and glucose, lipid panel, C-reactive protein, and cognitive function. A pilot trial of n = 6 was conducted to help develop procedures and address problems that could arise in the main trial. DISCUSSION: Successful completion of this study will provide the empirical basis for novel intervention and design strategies to enhance the impact of AVGs on long-term MVPA.

Hyperglycaemia is associated with impaired muscle signalling and aerobic adaptation to exercise.

Increased aerobic exercise capacity, as a result of exercise training, has important health benefits. However, some individuals are resistant to improvements in exercise capacity, probably due to undetermined genetic and environmental factors. Here, we show that exercise-induced improvements in aerobic capacity are blunted and aerobic remodelling of skeletal muscle is impaired in several animal models associated with chronic hyperglycaemia. Our data point to chronic hyperglycaemia as a potential negative regulator of aerobic adaptation, in part, via glucose-mediated modifications of the extracellular matrix, impaired vascularization and aberrant mechanical signalling in muscle. We also observe low exercise capacity and enhanced c-Jun N-terminal kinase activation in response to exercise in humans with impaired glucose tolerance. Our work indicates that current shifts in dietary and metabolic health, associated with increasing incidence of hyperglycaemia, might impair muscular and organismal adaptations to exercise training, including aerobic capacity as one of its key health outcomes.

Effect of ß-Lactam Plus Macrolide Versus Fluoroquinolone on 30-Day Readmissions for Community-Acquired Pneumonia.

BACKGROUND: Antibiotic therapy with a macrolide and ß-lactam or a fluoroquinolone for the empirical treatment of community-acquired pneumonia (CAP) in an inpatient non-intensive care setting is recommended per guidelines. Studies show that these treatments have similar outcomes, including death, adverse effects, and bacterial eradication. However, a comparison of 30-day readmission rates between these treatments is limited. STUDY QUESTION: To determine whether 30-day readmissions for patients treated for CAP in a regional hospital differed between a fluoroquinolone monotherapy and a ß-lactam plus macrolide combination therapy. STUDY DESIGN: Retrospective cohort study of patients aged ≥18 years with a CAP diagnosis who were admitted to the same regional hospital from December 1, 2011, through December 1, 2016. MEASURES AND OUTCOMES: Patients receiving a third-generation cephalosporin plus macrolide were compared with those receiving a respiratory fluoroquinolone. Exclusion criteria were concurrent or recent use of the study antibiotics; death, transfer, or transition to hospice; and diagnosis of hospital-acquired pneumonia or health care-associated pneumonia. The collected data were 30-day readmission rates, antibiotic regimens, demographic characteristics, and pneumonia severity index and comorbidity scores. Association between treatment group and readmissions was assessed with logistic regression. Association between readmissions and individual data points between the 2 treatment groups was calculated with multivariate regression and odds ratio (95% confidence interval). RESULTS: Of 432 patients, 171 met inclusion criteria (fluoroquinolone group, n = 101; ß-lactam plus macrolide group, n = 70). Thirty-day readmissions were not significantly different between the fluoroquinolone group and ß-lactam plus macrolide group (P = 0.58). Increased 30-day readmissions were independently associated with male sex and hospital length of stay (P < 0.05). Length of stay was approximately 3 days and did not differ between treatment groups. CONCLUSIONS: No difference was seen in 30-day readmissions between CAP patients who received fluoroquinolone monotherapy and those who received ß-lactam plus macrolide combination therapy.

Reduced sucrose nonfermenting AMPK-related kinase (SNARK) activity aggravates cancer-induced skeletal muscle wasting.

Sucrose nonfermenting AMPK-related kinase (SNARK) is a member of the AMPK family of kinases and has been implicated in the regulation of critical metabolic processes. Recent findings demonstrate that SNARK has an important role in the maintenance of muscle mass with age. Loss of skeletal muscle mass (cachexia) is a key problem for cancer patients. Thus, based on our previous findings with aging, we hypothesized that SNARK would play a role in regulating muscle mass under conditions of cancer cachexia. To test this hypothesis, Lewis Lung Carcinoma tumor cells or vehicle were injected subcutaneously in the right flank of wild type mice, muscle-specific transgenic mice expressing inactive SNARK mutant (SDN) or muscle-specific transgenic mice overexpressing wild-type SNARK (SWT). All tumor-bearing mice presented muscle wasting compared to vehicle-injected mice. However, SDN tumor-bearing mice had more pronounced atrophy compared to wild-type and SWT tumor-bearing mice. Histological analysis confirmed muscle atrophy in tumor-bearing mice, and SDN tumor-bearing mice exhibited a significantly smaller skeletal muscle cross-sectional area than wild-type and SWT tumor-bearing mice. Moreover, SDN tumor-bearing mice had increased skeletal muscle BAX protein expression, a marker of apoptosis, compared to other groups.Thus, lack of SNARK in skeletal muscle aggravates cancer-induced skeletal muscle wasting. These findings uncover a role for SNARK in the maintenance of skeletal muscle mass under cachexia conditions.

Perceptions and practices of mosquito-borne diseases in Alabama - is concern where it should be?

BACKGROUND: The Gulf Coast of the United States is home to mosquito vectors that may spread disease causing pathogens, and environmental conditions that are ideal for the sustained transmission of mosquito-borne pathogens. Understanding public perceptions of mosquito-borne diseases and mosquito prevention strategies is critical for the development of effective vector control strategies and public health interventions. Here, we present a survey conducted in Mobile, Alabama along the Gulf Coast to better understand public perceptions of mosquito-borne diseases, mosquito control activities, and potential risk factors. METHODS: Using Knowledge, Attitude, and Practice (KAPs) assessments, we surveyed populations living in 12 zip codes in Mobile, Alabama using a 7-point Likert scale and frequency assessments. Survey participants were asked about vector control efforts, knowledge of mosquito-borne diseases, and understanding of mosquito ecology and breeding habitats. RESULTS: One hundred twenty-six surveys were completed in Mobile, Alabama, revealing that 73% of participants reported being bitten by a mosquito in the last 30 days and mosquitoes were frequently seen in their homes. Ninety-four percent of respondents had heard of Zika Virus at the time of the survey, and respondents reported being least familiar with dengue virus and chikungunya virus. CONCLUSIONS: Chikungunya virus, dengue virus, malaria, West Nile virus, and Zika virus have been documented in the Gulf Coast of the United States. The mosquitoes which vector all of these diseases are presently in the Gulf Coast meaning all five diseases pose a potential risk to human health. The results of this survey emphasize knowledge gaps that public health officials can address to empower the population to reduce their risk of these mosquito-borne diseases. Each species of mosquito has specific preferences for breeding and feeding and there is no one size fits all prevention approach, educating people on the need for a variety of approaches in order to address all species will further empower them to control mosquitoes where they live and further reduce their risk of disease.

Meta-omics analysis of elite athletes identifies a performance-enhancing microbe that functions via lactate metabolism.

The human gut microbiome is linked to many states of human health and disease1. The metabolic repertoire of the gut microbiome is vast, but the health implications of these bacterial pathways are poorly understood. In this study, we identify a link between members of the genus Veillonella and exercise performance. We observed an increase in Veillonella relative abundance in marathon runners postmarathon and isolated a strain of Veillonella atypica from stool samples. Inoculation of this strain into mice significantly increased exhaustive treadmill run time. Veillonella utilize lactate as their sole carbon source, which prompted us to perform a shotgun metagenomic analysis in a cohort of elite athletes, finding that every gene in a major pathway metabolizing lactate to propionate is at higher relative abundance postexercise. Using 13C3-labeled lactate in mice, we demonstrate that serum lactate crosses the epithelial barrier into the lumen of the gut. We also show that intrarectal instillation of propionate is sufficient to reproduce the increased treadmill run time performance observed with V. atypica gavage. Taken together, these studies reveal that V. atypica improves run time via its metabolic conversion of exercise-induced lactate into propionate, thereby identifying a natural, microbiome-encoded enzymatic process that enhances athletic performance.

Sucrose nonfermenting AMPK-related kinase (SNARK) regulates exercise-stimulated and ischemia-stimulated glucose transport in the heart.

The signaling mechanisms mediating myocardial glucose transport are not fully understood. Sucrose nonfermenting AMP-activated protein kinase (AMPK)-related kinase (SNARK) is an AMPK-related protein kinase that is expressed in the heart and has been implicated in contraction-stimulated glucose transport in mouse skeletal muscle. We first determined if SNARK is phosphorylated on Thr208 , a site critical for SNARK activity. Mice were treated with exercise, ischemia, submaximal insulin, or maximal insulin. Treadmill exercise slightly, but significantly increased SNARK Thr208 phosphorylation. Ischemia also increased SNARK Thr208 phosphorylation, but there was no effect of submaximal or maximal insulin. HL1 cardiomyocytes were used to overexpress wild-type (WT) SNARK and to knockdown endogenous SNARK. Overexpression of WT SNARK had no effect on ischemia-stimulated glucose transport; however, SNARK knockdown significantly decreased ischemia-stimulated glucose transport. SNARK overexpression or knockdown did not alter insulin-stimulated glucose transport or glycogen concentrations. To study SNARK function in vivo, SNARK heterozygous knockout mice (SNARK+/- ) and WT littermates performed treadmill exercise. Exercise-stimulated glucose transport was decreased by ~50% in hearts from SNARK+/- mice. In summary, exercise and ischemia increase SNARK Thr208 phosphorylation in the heart and SNARK regulates exercise-stimulated and ischemia-stimulated glucose transport. SNARK is a novel mediator of insulin-independent glucose transport in the heart.

JNK regulates muscle remodeling via myostatin/SMAD inhibition.

Skeletal muscle has a remarkable plasticity to adapt and remodel in response to environmental cues, such as physical exercise. Endurance exercise stimulates improvements in muscle oxidative capacity, while resistance exercise induces muscle growth. Here we show that the c-Jun N-terminal kinase (JNK) is a molecular switch that when active, stimulates muscle fibers to grow, resulting in increased muscle mass. Conversely, when muscle JNK activation is suppressed, an alternative remodeling program is initiated, resulting in smaller, more oxidative muscle fibers, and enhanced aerobic fitness. When muscle is exposed to mechanical stress, JNK initiates muscle growth via phosphorylation of the transcription factor, SMAD2, at specific linker region residues leading to inhibition of the growth suppressor, myostatin. In human skeletal muscle, this JNK/SMAD signaling axis is activated by resistance exercise, but not endurance exercise. We conclude that JNK acts as a key mediator of muscle remodeling during exercise via regulation of myostatin/SMAD signaling.