Whole-blood transcriptome analysis reveals distinct gene expression signatures in paediatric patients with sickle cell anaemia before and after exercise.

Sickle cell anaemia (SCA) patients display elevated levels of circulating pro-inflammatory cytokines and endothelial activation markers compared to healthy peers. The impact of exercise on the pro-inflammatory state in SCA remains unclear. This study aimed to characterize the whole-blood transcriptome profile in response to an acute bout of exercise in paediatric SCA patients. Twenty-three SCA participants (13 ± 3 years, 52% girls) and 17 healthy controls (14 ± 3 years, 29% girls) performed eight 2-min bouts of cycle ergometry interspersed with 1-min rest intervals. Whole-blood transcriptome profile (RNA-seq) was performed before and after exercise. At baseline, gene pathways associated with gas transport in erythrocytes were up-regulated in SCA patients compared to controls. Following exercise, gene pathways associated with innate immunity were altered in both groups. Interaction analyses revealed 160 annotated genes (101 up- and 59 down-regulated) that differentially altered by exercise in SCA patients. Moreover, genes that exhibited a blunted response to exercise in SCA patients were enriched in the IL-17 signalling pathway, suggesting an impaired innate immune response to exercise. This data will contribute to the development of evidence-based exercise prescription guidelines for this patient population.

Molecular Transducers of Physical Activity Consortium (MoTrPAC): Human Studies Design and Protocol.

Physical activity, including structured exercise, is associated with favorable health-related chronic disease outcomes. While there is evidence of various molecular pathways that affect these responses, a comprehensive molecular map of these molecular responses to exercise has not been developed. The Molecular Transducers of Physical Activity Consortium (MoTrPAC) is a multi-center study designed to isolate the effects of structured exercise training on the molecular mechanisms underlying the health benefits of exercise and physical activity. MoTrPAC contains both a pre-clinical and human component. The details of the human studies component of MoTrPAC that include the design and methods are presented here. The human studies contain both an adult and pediatric component. In the adult component, sedentary participants are randomized to 12 weeks of Control, Endurance Exercise Training, or Resistance Exercise Training with outcomes measures completed before and following the 12 weeks. The adult component also includes recruitment of highly active endurance trained or resistance trained participants who only complete measures once. A similar design is used for the pediatric component; however, only endurance exercise is examined. Phenotyping measures include weight, body composition, vital signs, cardiorespiratory fitness, muscular strength, physical activity and diet, and other questionnaires. Participants also complete an acute rest period (adults only) or exercise session (adults, pediatrics) with collection of biospecimens (blood only for pediatrics) to allow for examination of the molecular responses. The design and methods of MoTrPAC may inform other studies. Moreover, MoTrPAC will provide a repository of data that can be used broadly across the scientific community.

Exercise Training Attenuates the Muscle Mitochondria Genomic Response to Bed Rest.

PURPOSE: Exercise training during the National Aeronautics and Space Administration (NASA) 70-day bed rest study effectively counteracted the decline in aerobic capacity, muscle mass, strength, and endurance. We aimed to characterize the genomic response of the participants' vastus lateralis (VL) on day 64 of bed rest with and without exercise countermeasures. METHODS: Twenty-two healthy young males were randomized into three groups: 1) bed rest only (n = 7), 2) bed rest + aerobic (6 d/wk) and resistance training (3 d/wk) on standard equipment (n = 7), and 3) bed rest + aerobic and resistance training using a flywheel device (n = 8). The VL gene and microRNA microarrays were analyzed using GeneSpring GX 14.9.1. RESULTS: Bed rest significantly altered the expression of 2113 annotated genes in at least one out of the three study groups (fold change (FC) > 1.2; P < 0.05). Interaction analysis revealed that exercise attenuated the bed rest effect of 511 annotated genes (FC 1.2, P < 0.05). In the bed rest only group, a predominant downregulation of genes was observed while in the two exercise groups there was a notable attenuation or reversal of this effect, with no significant differences between the two exercise modalities. Enrichment analysis identified functional categories and gene pathways, many of them related to the mitochondria. Additionally, bed rest significantly altered the expression of 35 microRNAs (FC > 1.2, P < 0.05) with no difference between the three groups. Twelve are known to regulate some of the mitochondrial-related genes that were altered following bed rest. CONCLUSIONS: Mitochondrial gene expression was a significant component of the molecular response to long-term bed rest. While exercise attenuated the FC in the downregulation of many genes, it did not completely counteract all the molecular consequences.

Effects of physical exercise, LEGO, and Minecraft activities on anxiety in underserved children with autism: Study design and methodological strategies.

Anxiety is a common comorbidity for individuals with ASD, and there is some preliminary data about the efficacy of physical exercise to alleviate anxiety. However, we are not aware of any studies that have compared the effects of a physical exercise program on anxiety in underserved children with ASD using a randomized controlled research design. This paper describes a method to evaluate and compare the efficacy of an 8-week physical exercise intervention with a sedentary play intervention to alleviate anxiety in young children with autism spectrum disorders (ASD) from underserved backgrounds. We assessed anxiety and its physical symptoms using the parent-rated Child Behavior Checklist DSM-5 anxiety (CBCL DSM-5) subscale, the child-rated Screen for Childhood Anxiety Related Emotional Disorder (SCARED), the parent-rated Child's Sleep Habits Questionnaire (CSHQ), and salivary cortisol. We also utilized the Physical Activity Questionnaire for Older Children (PAQ-C) to assess physical activity level and identify compounds. Unique components of this study include: •Implementation of novel physical exercise and sedentary play interventions that have been designed for children with ASD.•Recruitment of predominantly underserved and non-English speaking families.

Genetic Factors, Brain Atrophy, and Response to Rehabilitation Therapy After Stroke.

OBJECTIVE: Patients show substantial differences in response to rehabilitation therapy after stroke. We hypothesized that specific genetic profiles might explain some of this variance and, secondarily, that genetic factors are related to cerebral atrophy post-stroke. METHODS: The phase 3 ICARE study examined response to motor rehabilitation therapies. In 216 ICARE enrollees, DNA was analyzed for presence of the BDNF val66met and the ApoE ε4 polymorphism. The relationship of polymorphism status to 12-month change in motor status (Wolf Motor Function Test, WMFT) was examined. Neuroimaging data were also evaluated (n=127). RESULTS: Subjects were 61±13 years old (mean±SD) and enrolled 43±22 days post-stroke; 19.7% were BDNF val66met carriers and 29.8% ApoE ε4 carriers. Carrier status for each polymorphism was not associated with WMFT, either at baseline or over 12 months of follow-up. Neuroimaging, acquired 5±11 days post-stroke, showed that BDNF val66met polymorphism carriers had a 1.34-greater degree of cerebral atrophy compared to non-carriers (P=.01). Post hoc analysis found that age of stroke onset was 4.6 years younger in subjects with the ApoE ε4 polymorphism (P=.02). CONCLUSION: Neither the val66met BDNF nor ApoE ε4 polymorphism explained inter-subject differences in response to rehabilitation therapy. The BDNF val66met polymorphism was associated with cerebral atrophy at baseline, echoing findings in healthy subjects, and suggesting an endophenotype. The ApoE ε4 polymorphism was associated with younger age at stroke onset, echoing findings in Alzheimer's disease and suggesting a common biology. Genetic associations provide insights useful to understanding the biology of outcomes after stroke.

Effects of cold water immersion on circulating inflammatory markers at the Kona Ironman World Championship.

Cold water immersion (CWI) purportedly reduces inflammation and improves muscle recovery after exercise, yet its effectiveness in specific contexts (ultraendurance) remains unclear. Thus, our aim was to study hematological profiles, systemic inflammation, and muscle damage responses to a specific post-race CWI (vs. control) during recovery after the Ironman World Championship, a culmination of ∼100 000 athletes competing in global qualifying Ironman events each year. Twenty-nine competitors were randomized into either a CWI or control (CON) group. Physiological parameters and blood samples were taken at pre-race, after intervention (POST), and 24 (+1DAY) and 48 hours (+2DAY) following the race. Muscle damage markers (plasma myoglobin, serum creatine kinase) were elevated at POST, +1DAY, and +2DAY, while inflammatory cytokines interleukin (IL)-6, IL-8, and IL-10 and total leukocyte counts were increased only at POST. CWI had no effect on these markers. Numbers of the most abundant circulating cell type, neutrophils, were elevated at POST more so in CWI (p < 0.05, vs. CON). Despite that neutrophil counts may be a sensitive marker to detect subtle effects, CWI does not affect recovery markers 24- and 48-hours post-race (vs. CON). Overall, we determined that our short CWI protocol was not sufficient to improve recovery. Novelty: Ironman World Championship event increased circulating muscle damage markers, inflammatory markers, and hematological parameters, including circulating immune cell sub-populations that recover 24-48 hours after the race. 12-min CWI post-ultraendurance event affects the absolute numbers of neutrophils acutely, post-race (vs. CON), but does not impact recovery 24- and 48-hours post-race.

Regulation of myosin heavy chain antisense long noncoding RNA in human vastus lateralis in response to exercise training.

Alterations to muscle activity or loading state can induce changes in expression of myosin heavy chain (MHC). For example, sedentary individuals that initiate exercise training can induce a pronounced shift from IIx to IIa MHC. We sought to examine the regulatory response of MHC RNA in human subjects in response to exercise training. In particular, we examined how natural antisense RNA transcripts (NATs) are regulated throughout the MHC gene locus that includes MYH2 (IIa), MYH1 (IIx), MYH4 (IIb), and MYH8 (Neonatal) in vastus lateralis before and after a 5-wk training regime that consisted of a combination of aerobic and resistance types of exercise. The exercise program induced a IIx to IIa MHC shift that was associated with a corresponding increase in transcription on the antisense strand of the IIx MHC gene and a decrease in antisense transcription of the IIa MHC gene, suggesting an inhibitory mechanism mediated by NATs. We also report that the absence of expression of IIb MHC in human limb muscle is associated with the abundant expression of antisense transcript overlapping the IIb MHC coding gene, which is the opposite expression pattern as compared with that previously observed in rats. The NAT provides a possible regulatory mechanism for the suppressed expression of IIb MHC in humans. These data indicate that NATs may play a regulatory role with regard to the coordinated shifts in MHC gene expression that occur in human muscle in response to exercise training.

Body composition and neuromotor development in the year after NICU discharge in premature infants.

BACKGROUND: Hypothesis: neuromotor development correlates to body composition over the first year of life in prematurely born infants and can be influenced by enhancing motor activity. METHODS: Forty-six female and 53 male infants [27 ± 1.8 (sd) weeks] randomized to comparison or exercise group (caregiver provided 15-20 min daily of developmentally appropriate motor activities) completed the year-long study. Body composition [lean body and fat mass (LBM, FM)], growth/inflammation predictive biomarkers, and Alberta Infant Motor Scale (AIMS) were assessed. RESULTS: AIMS at 1 year correlated with LBM (r = 0.32, p < 0.001) in the whole cohort. However, there was no effect of the intervention. LBM increased by ~3685 g (p < 0.001)); insulin-like growth factor-1 (IGF-1) was correlated with LBM (r = 0.36, p = 0.002). IL-1RA (an inflammatory biomarker) decreased (-75%, p < 0.0125). LBM and bone mineral density were significantly lower and IGF-1 higher in the females at 1 year. CONCLUSIONS: We found an association between neuromotor development and LBM suggesting that motor activity may influence LBM. Our particular intervention was ineffective. Whether activities provided largely by caregivers to enhance motor activity in prematurely born infants can affect the interrelated (1) balance of growth and inflammation mediators, (2) neuromotor development, (3) sexual dimorphism, and/or (4) body composition early in life remains unknown.

A Six Week Therapeutic Ballet Intervention Improved Gait and Inhibitory Control in Children With Cerebral Palsy-A Pilot Study.

Children with cerebral palsy (CP) have motor impairments that make it challenging for them to participate in standard physical activity (PA) interventions. There is a need to evaluate adapted PA interventions for this population. Dance can promote coordination, posture, muscle strength, motor learning, and executive functioning. This pilot study evaluated the feasibility and the effects of a new therapeutic ballet intervention specifically designed for children with CP. Methods: Eight children with CP (9-14 y/o; 75% female) participated in a 6-week therapeutic ballet intervention. Outcomes were measured in multiple domains, including body composition (DXA), muscle strength (hand-grip dynamometer), habitual physical activity, gait and selective motor control functions, and executive functioning. Follow-up assessments of habitual physical activity, gait, and executive functioning were completed 4 to 5 weeks post-intervention. Results: Five of the eight participants were overfat or obese based on DXA percentage of body fat. All participants were below the 50th percentile for their age and gender for bone density. Four participants showed a trend to improve hand-grip strength in one hand only, while one improved in both hands. There were significant improvements in gait across time points (pre, post, and follow-up), specifically in time of ambulation (X pre = 4.36, X post = 4.22, X follow-up = 3.72, d = 0.056, p = 0.02), and in step length (cm) on the right: X pre = 48.29, X post = 50.77, X follow-up = 52.11, d = 0.22, p = 0.027, and left stride: X pre = 96.29, X post = 102.20, X follow-up = 104.20, d = 0.30, p = 0.027, indicating gait changes in bilateral lower extremities. There was improvement in inhibitory control (d = 0.78; 95% Confidence Limit = ±0.71, p < 0.05) with large individual responses primarily among those above the mean at baseline. Conclusions: Therapeutic ballet may prove to be a useful intervention to promote physiological and cognitive functions in children with CP. Results demonstrated feasibility of the physical, physiological, and cognitive assessments and suggested improvements in participants' gait and inhibitory control with large individual responses. Modifications to personalize the intervention may be needed to optimize positive outcomes. Clinical Trial Registration: www.ClinicalTrials.gov, identifier: NCT03681171.

Tele-Exercise as a Promising Tool to Promote Exercise in Children With Cystic Fibrosis.

Introduction: Cross-infection risk from contact exposure limits exercise opportunities in children with cystic fibrosis (CF). The purpose of this study is to evaluate the feasibility of a new live-streamed platform which delivered supervised and interactive group exercise sessions to CF children via digital devices while avoiding contact exposure. Methods: Ten CF children participated in a 6-week tele-exercise program. The program consisted of three 30-min sessions per week for a total of 18 sessions and included aerobic, resistance, and flexibility exercises. Sessions were streamed via a HIPAA compliant VSee telemedicine platform. Instructors and participants were able to interact in real-time online. Heart rate (HR) monitors were used to evaluate exercise intensity with a goal of moderate-vigorous physical activity ≥10 min, 70% of the sessions. System usability scale (SUS) and qualitative questionnaires were used to gauge participants' satisfaction and feedback. Results: On average participants attended 85% of the sessions. For the overall sessions participants exercise 21.1 ± 6.9 min at moderate-vigorous physical activity. Nine out of 10 participants used the exercise platform without parental guidance. Qualitative questionnaire and System Usability Scale (SUS) indicated that all participants enjoyed the tele-exercise program and highly rated the exercise platform 90.8 out of 100 (passing > 68). Conclusions: Tele-exercise platform is a promising new approach to promote exercise in children with CF. The online platform allows supervised virtual group exercise experience with optimal participation and no risk for cross-infection. This approach might prove to be useful in enhancing the use of exercise as therapy in children with CF.

Triiodothyronine and leptin repletion in humans similarly reverse weight-loss-induced changes in skeletal muscle.

Subjects maintaining a ≥10% dietary weight loss exhibit decreased circulating concentrations of bioactive thyroid hormones and increased skeletal muscle work efficiency largely due to increased expression of more-efficient myosin heavy chain (MHC) isoforms (MHC I) and significantly mediated by the adipocyte-derived hormone leptin. The primary purpose of this study was to examine the effects of triiodothyronine (T3) repletion on energy homeostasis and skeletal muscle physiology in weight-reduced subjects and to compare these results with the effects of leptin repletion. Nine healthy in-patients with obesity were studied at usual weight (Wtinitial) and following a 10% dietary weight loss while receiving 5 wk of a placebo (Wt-10%placebo) or T3 (Wt-10%T3) in a single-blind crossover design. Primary outcome variables were skeletal muscle work efficiency and vastus lateralis muscle mRNA expression. These results were compared with the effects of leptin repletion in a population of 22 subjects, some of whom participated in a previous study. At Wt-10%placebo, skeletal muscle work efficiency and relative expression of the more-efficient/less-efficient MHC I/MHC II isoforms were significantly increased and the ratio of the less-efficient to the more-efficient sarco(endo)plasmic reticulum Ca2+-ATPase isoforms (SERCA1/SERCA2) was significantly decreased. These changes were largely reversed by T3 repletion to a degree similar to the changes that occurred with leptin repletion. These data support the hypothesis that the effects of leptin on energy expenditure in weight-reduced individuals are largely mediated by T3 and suggest that further study of the possible role of thyroid hormone repletion as adjunctive therapy to help sustain weight loss is needed.

A Translational Model of Incomplete Catch-Up Growth: Early-Life Hypoxia and the Effect of Physical Activity.

Advances in therapies have led to prolonged survival from many previously lethal health threats in children, notably among prematurely born babies and those with congenital heart disease. Evidence for catch-up growth is common in these children, but in many cases the adult phenotype is never achieved. A translational animal model is required in which specific tissues can be studied over a reasonable time interval. We investigated the impact of postnatal hypoxia (HY) (12%O2 (HY12) or 10% O2 (HY10)) on growth in rats relative to animals raised in room air. Subgroups had access to running wheels following the HY period. Growth was fully compensated in adult HY12 rats but not HY10 rats. The results of this study indicate that neonatal hypoxia can be a useful model for the elucidation of mechanisms that mediate successful catch-up growth following neonatal insults and identify the critical factors that prevent successful catch-up growth.

Four Months of a School-Based Exercise Program Improved Aerobic Fitness and Clinical Outcomes in a Low-SES Population of Normal Weight and Overweight/Obese Children With Asthma.

Introduction: Fitness can improve asthma management. However, children from disadvantaged and minority communities generally engage less in physical activity, and have increased obesity and asthma disease burden. The goal of this pilot study is to evaluate (1) the feasibility of an exercise intervention program in a school-based setting (attendance and fitness improvement) and (2) the effect of the intervention on fitness, asthma, and clinical outcomes in normal weight and overweight/obese children with asthma from low-SES population. Materials and Methods: Nineteen children, ages 6-13 years, from two elementary schools in Santa Ana, CA, a population with high percentage of Hispanic and low socioeconomic status, participated. Training sessions occurred at the schools during afterschool hours (3 sessions weekly × 4 months) and included mainly aerobic age-appropriate activities/games and a small component of muscle strength. Before and after the intervention, evaluations included pulmonary function testing, cardiopulmonary exercise testing (peak V ˙ O2), assessments of habitual physical activity, body composition (DXA), asthma questionnaires, and blood (cardiometabolic risk factors). Results: Seventeen of 19 participants completed the study. Adherence to the program was 85%. Based on BMI %ile, 11 of the participants were overweight/obese and 8 were normal weight. Ten participants had persistent asthma and 9 children had intermittent asthma. Training was effective as peak V ˙ O2 improved significantly (8.1%, SD ± 10.1). There was no significant change in BMI %ile but a significant improvement in lean body mass (1%, SD ± 2.0) and decrease in body fat (1.9%, SD ± 4.6). Asthma quality of life outcomes improved following the intervention in symptoms, emotional function, and overall. There was no change in asthma control or pulmonary function. Five of 10 participants with persistent asthma decreased their maintenance medications. Lipid levels did not change except HDL levels increased (46.1 ± 8.4 mg/dL to 49.5 ± 10.4 mg/dL, p = 0.04). Discussion: A school-based exercise intervention program designed specifically for children with asthma for a predominantly economically disadvantaged and minority population was feasible with good adherence to the program and substantial engagement from the schools, families and participants. The exercise intervention was effective with improvement in aerobic fitness, body composition, asthma quality of life, and lipid outcomes, setting the stage for a larger multicenter trial designed to study exercise as an adjunct medicine in children with asthma.

Inter- and intra-subject variability of nitric oxide levels in leukocyte subpopulations.

Assessment of nitric oxide (NO) dynamics in immune cells, commonly measured using NO surrogates such as inducible nitric oxide synthase (iNOS) rather than NO itself, has been effective in understanding pathophysiology across a wide range of diseases. Although the intracellular measurement of NO is now feasible, many technical issues remain unresolved. The principle aim of our study was to determine the effect of storage time of whole blood on nitric oxide (NO) level expression in leukocytes. This is important because immune cells remain chemically dynamic even after they are removed from the circulation, and the impact of storage time must be known to optimally quantify the effect of a disease or condition on NO dynamics in circulating leukocytes. We measured NO levels using the fluorescent probe, diaminofluorescein (DAF-2DA), and flow cytometry in monocytes, neutrophils, and natural killer cells from healthy subjects immediately after blood draw (Time 0) and 30, 60, and 120 min following the blood draw. There was no significant difference among the 4 study time points in NO (DAF-2) levels, though there was wide intra-subject variability at all time points. Using LPS stimulation, we compared iNOS (the more traditional surrogate marker of NO dynamics) with NO (by DAF-2) in natural killer cells and monocytes and, we found no difference in the response patterns. In summary, we did find that within a 2-hour interval from blood draw to sample processing, there was a remarkably wide intra-subject variability in expression of intracellular NO (DAF-2) in leukocytes of healthy individuals at baseline and over time. The mechanism(s) for these differences are not known but could clearly confound efforts to detect changes in NO metabolism in white blood cells. We speculate that rapid pulsatility of NO could explain the wide variability seen.

Glucocorticoid receptor expression on circulating leukocytes in healthy and asthmatic adolescents in response to exercise.

BackgroundPoor aerobic fitness is associated with worsening of asthma symptoms, and fitness training may improve asthma control. The mechanism linking fitness with asthma is not known. We hypothesized that repeated bouts of exercise would lead to a downregulation of glucocorticoid receptor (GR) expression on circulating leukocytes, reflecting a reduced responsiveness to stress.MethodsIn a prospective exercise training intervention of healthy and asthmatic adolescents, GR expression in leukocytes was measured using flow cytometry in response to an acute exercise challenge before and after the exercise training intervention. Peripheral blood mononuclear cell (PBMC) gene expression of GR, GRß, HSP70, TGFß1, and TGFß2 was determined using reverse-transcriptase PCR (RT-PCR).ResultsPeak VO2 increased by 14.6±2.3%, indicating an effective training (P<0.01). There was a significant difference in GR expression among leukocyte subtypes, with highest expression in eosinophils. Following the exercise training intervention, there was a significant decrease in baseline GR expression (P<0.05) in leukocyte and monocyte subtypes in both healthy and asthmatic adolescents.ConclusionsThis is the first study in adolescents to show that exercise training reduces GR expression in circulating leukocytes. We speculate that exercise training downregulates the stress response in general, manifested by decreased GR expression, and may explain why improving fitness improves asthma health.

Glucocorticoid receptor expression on circulating leukocytes differs between healthy male and female adults.

INTRODUCTION: The glucocorticoid receptor (GR) is a key receptor involved in inflammatory responses and is influenced by sex steroids. This study measured GR expression on circulating leukocyte subtypes in males and females. METHODS: A total of 23 healthy adults (12 female) participated in this study. GR expression was measured in leukocyte subtypes using flow cytometry. Peripheral blood mononuclear cell (PBMC) gene expression of GR (NR3C1), GR ß, TGF-ß1 and 2, and glucocorticoid-induced leucine zipper (GILZ) were determined by real-time polymerase chain reaction. RESULTS: Leukocyte GR was lower in females, particularly in granulocytes, natural killer cells, and peripheral blood mononuclear cells (p≤0.01). GR protein expression was different across leukocyte subtypes, with higher expression in eosinophils compared with granulocytes, T lymphocytes, and natural killer cells (p<0.05). There was higher gene expression of GR ß in males (p=0.03). CONCLUSIONS: This is the first study to identify sexual dimorphism in GR expression in healthy adults using flow cytometry. These results may begin to explain the sexual dimorphism seen in many diseases and sex differences in glucocorticoid responsiveness.

Exercise Responses to Gravity-Independent Flywheel Aerobic and Resistance Training.

BACKGROUND: Although several exercise systems have been developed to mitigate the physiological deconditioning that occurs in microgravity, few have the capacity to positively impact multiple physiological systems and still meet the volume/mass requirements needed for missions beyond low Earth orbit. The purpose of this study was to test the gravity-independent Multi-Mode Exercise Device (M-MED) for both resistance (RE) and aerobic (AE) training stimuli. METHODS: Eight men and nine women (mean age 22.0 ± 0.4 yr) completed 5 wk of training on the M-MED: RE 4 × 7 squats 2 d/wk, and AE 4 × 4-min rowing bouts at ∼90% Vo2max 3 d/wk. Pre- and post-training data collection included an aerobic capacity test, MR imaging, strength testing, and vastus lateralis muscle biopsy. RESULTS: Vo2max increased 8%, 3RM strength 18%, and quadriceps femoris cross-sectional area (CSA) 10%. Knee extensor strength increased at all isokinetic speeds tested. Subjects also demonstrated improved fatigue resistance in knee extension. At the cellular and molecular level, the biopsy revealed increases in mixed myofiber CSA (13%), citrate synthase activity (26%), total RNA concentration (24%), IGF-I mRNA (77%), and Type IIa myosin heavy chain (MHC) mRNA (8%), and a concomitant decrease in Type IIx MHC mRNA (-23%). None of the changes were gender-specific. DISCUSSION: Both the functional outcomes and biomarker changes indicate that a very low volume of M-MED exercise results in robust adaptation in the cardiovascular and musculoskeletal systems. The M-MED has the potential to provide a wide range of countermeasure exercises and should be considered for testing in ground-based spaceflight simulation.

Concurrent exercise on a gravity-independent device during simulated microgravity.

PURPOSE: The objective of this study is to examine the effect of a high-intensity concurrent training program using a single gravity-independent device on maintaining skeletal muscle function and aerobic capacity during short-term unilateral lower limb suspension (ULLS). METHODS: Nineteen subjects (10 males and 9 females; 21.0 ± 2.5 yr, 65.4 ± 12.2 kg) were separated into two groups: 1) 10-d ULLS only (n = 9) and 2) 10-d ULLS plus aerobic and resistance training (ULLS + EX, n = 10). Exercise was performed on a single gravity-independent Multi-Mode Exercise Device (M-MED) with alternating days of high-intensity interval aerobic training and maximal exertion resistance training. RESULTS: Aerobic capacity increased by 7% in ULLS + EX (P < 0.05). Knee extensor and ankle plantar flexor three-repetition maximum increased in the ULLS + EX group (P < 0.05), but this change was only different from ULLS in the plantar flexors (P < 0.05). Peak torque levels decreased with ULLS but were increased for the knee extensors and attenuated for the ankle plantar flexors with ULLS + EX (P < 0.05). A shift toward type IIx myosin heavy-chain mRNA occurred with ULLS and was reversed with ULLS + EX in the vastus lateralis (P < 0.05) but not the soleus. Myostatin and atrogin increased with ULLS in both the vastus lateralis and soleus, but this change was mitigated with ULLS + EX only in the vastus lateralis (P = 0.0551 for myostatin, P < 0.05 for atrogin). Citrate synthase was decreased in the soleus during ULLS but was increased with ULLS + EX (P < 0.05). CONCLUSION: These results indicate that an M-MED class countermeasure device appears to be effective at mitigating the deconditioning effects of microgravity simulated during a modified ULLS protocol.

Impact of brief exercise on circulating monocyte gene and microRNA expression: implications for atherosclerotic vascular disease.

Physical activity can prevent and/or attenuate atherosclerosis, a disease clearly linked to inflammation. Paradoxically, even brief exercise induces a stress response and increases inflammatory cells like monocytes in the circulation. We hypothesized that exercise would regulate the expression of genes, gene pathways, and microRNAs in monocytes in a way that could limit pro-inflammatory function and drive monocytes to prevent, rather than contribute to, atherosclerosis. Twelve healthy men (22-30year old) performed ten 2-min bouts of cycle ergometer exercise at a constant work equivalent to an average of 82% of maximum O2 consumption interspersed with 1-min rest. Blood was drawn before and immediately after the exercise. Monocytes were isolated from peripheral blood mononuclear cells. Flow cytometry was used to identify monocyte subtypes. We used Affymetrix U133 + 2.0 arrays for gene expression and Agilent Human miRNA V2 Microarray for miRNAs. A stringent statistical approach (FDR <0.05) was used to determine that exercise significantly altered the expression of 894 annotated genes and 19 miRNAs. We found distinct gene alterations that were likely to direct monocytes in an anti-inflammatory, anti-atherogenic pathway, including the downregulation of monocyte TNF, TLR4, and CD36 genes and the upregulation of EREG and CXCR4. Exercise significantly altered a number of microRNAs that likely influence monocytes involvement in vascular health. Exercise leads to a novel genomic profile of circulating monocytes, which appears to promote cardiovascular health despite the overall stress response.

Suction-modified needle biopsy technique for the human soleus muscle.

INTRODUCTION: The needle biopsy technique for the soleus muscle is of particular interest because of the muscle's unique fiber type distribution, contractile properties, and sensitivity to unloading. Unlike other commonly biopsied muscles, the soleus is not fully superficial and is in close proximity to neurovascular structures, resulting in a more challenging biopsy. Because of this, a standardized protocol for performing needle biopsies on the human soleus muscle that is safe, reliable, and repeatable is presented. METHODS: Ultrasonography was used on an initial set of 12 subjects to determine the optimal biopsy zone, thereby guiding the location of the incision site. There were 45 subjects recruited who attended 2 separate biopsy sessions. Each biopsy session incorporated 3 passes of the biopsy needle proximal, posterior, and distal using suction from a portable vacuum source producing 3 separate muscle specimens. RESULTS: There were 84 soleus muscle biopsy procedures which were successfully conducted yielding 252 total samples without complication. Ultrasonography was used to confirm biopsy needle infiltration of the soleus muscle. Average sample weight obtained per pass was 61.5 +/- 15.7 mg. Histochemistry and molecular analyses demonstrated a considerably higher amount of slow type I MHC in comparison to the vastus lateralis, providing verification for the successful sampling of the soleus muscle. DISCUSSION: The procedure presented consists of a detailed protocol to accurately and consistently obtain muscle biopsy samples from the human soleus muscle. We have demonstrated that the human soleus biopsy is a safe, reliable, and repeatable procedure providing ample tissue for multiple types of analyses.