Szu-Yun Leu

Effects of Exercise on microRNA Expression in Young Males Peripheral Blood Mononuclear Cells

MicroRNAs are increasingly seen as targets of drug discovery because they influence gene function acting both to silence and subtly modulate protein translation. Little is known about effects of dynamic physiological states on microRNA regulation in humans. We hypothesized that microRNA expression in peripheral blood mononuclear cells (PBMCs) would be affected by brief exercise. Twelve young men performed brief bouts of heavy exercise. PBMC microRNA was analyzed before and immediately after exercise using the Agilent Human microRNA V2 Microarray. Exercise altered expression level of 34 microRNAs (FDR < 0.05). Many of them play roles in inflammatory processes (e.g., miR‐125b[↓], down‐regulated by proinflammatory factor LPS; and miR‐132[↑], 125b[↓] and let‐7e[↓] involved inTLR4 signaling). Using previous exercise data in PBMCs, we linked the microRNA changes to specific gene pathways. This analysis identified 12 pathways including the TGF‐β and MAPK signaling. We also compared exercise‐associated microRNA changes in PBMCs with the exercise‐associated microRNAs previously identified in neutrophils. Nine microRNAs were affected in both PBMCs and neutrophils, but only six changed in the same direction. A commonly occurring physiologic perturbation, brief heavy exercise, changes microRNA profiles in PBMCs, many of which are related to inflammatory processes. The pattern of change suggests that exercise differentially influences microRNAs in leukocyte subtypes. Clin Trans Sci 2012; Volume #: 1–7

Body composition and its components in preterm and term newborns: A cross-sectional, multimodal investigation

A prospective, cross‐sectional, observational study in preterm and term infants was performed to compare multimodal measurements of body composition, namely, limb ultrasound, bone quantitative ultrasound, and dual X‐ray absorptiometry (DXA). One hundred and two preterm and term infants appropriate for gestational age were enrolled from the newborn nursery and neonatal intensive care unit. Infants were included when they were medically stable, in an open crib, on full enteral feeds and within 1 week of anticipated discharge. Correlations among the various measurements of body composition were performed using standard techniques. A comparison between preterm infant (born at 28–32 weeks) reaching term to term‐born infants was performed. Limb ultrasound estimates of cross‐sectional areas of lean and fat tissue in a region of tissue (i.e., the leg) were remarkably correlated with regional and whole‐body estimates of fat‐free mass and fat obtained from DXA suggesting the potential usefulness of muscle ultrasound as an investigative tool for studying aspects of body composition in this fragile population. There was a weak but significant correlation between quantitative ultrasound measurements of bone strength and DXA‐derived bone mineral density (BMD). Preterm infants reaching term had significantly lower body weight, length, head circumference, muscle and fat cross‐sectional area, bone speed of sound, whole‐body and regional lean body mass, fat mass, and BMD compared to term‐born infants. Current postnatal care and nutritional support in preterm infants is still unable to match the in‐utero environment for optimal growth and bone development. The use of relatively simple bedside, noninvasive body composition measurements may assist in understanding how changes in different components of body composition early in life affect later growth and development. Am. J. Hum. Biol. 2010.

A brief bout of exercise alters gene expression and distinct gene pathways in peripheral blood mononuclear cells of early- and late-pubertal females.

Recent studies show that brief exercise alters circulating neutrophil and peripheral blood mononuclear cell (PBMC) gene expression, ranging from cell growth to both pro-and anti-inflammatory processes. These initial observations were made solely in males, but whether PBMC gene expression is altered by exercise in females is not known. Ten early-pubertal girls (8-11 yr old) and 10 late-pubertal girls (15-17 yr old) performed ten 2-min bouts of cycle ergometry ( approximately 90% peak heart rate) interspersed with 1-min rest intervals. Blood was obtained at rest and after exercise, and microarrays were performed in each individual subject. RNA was hybridized to Affymetrix U133+2.0 Arrays. Exercise induced significant changes in PBMC gene expression in early (1,320 genes)- and late (877 genes)-pubertal girls. The expression of 622 genes changed similarly in both groups. Exercise influenced a variety of established gene pathways (EASE < 0.04) in both older (6 pathways) and younger girls (11 pathways). Five pathways were the same in both groups and were functionally related to inflammation, stress, and apoptosis, such as natural killer cell-mediated cytotoxicity, antigen processing and presentation, B cell receptor signaling, and apoptosis. In summary, brief exercise alters PBMC gene expression in early- and late-pubertal girls. The pattern of change involves diverse genetic pathways, consistent with a global danger-type response, perhaps readying PBMCs for a range of physiological functions from inflammation to tissue repair that would be useful following a bout of physical activity.

Acetaldehyde and hexanaldehyde from cultured white cells

BackgroundNoninvasive detection of innate immune function such as the accumulation of neutrophils remains a challenge in many areas of clinical medicine. We hypothesized that granulocytes could generate volatile organic compounds.MethodsTo begin to test this, we developed a bioreactor and analytical GC-MS system to accurately identify and quantify gases in trace concentrations (parts per billion) emitted solely from cell/media culture. A human promyelocytic leukemia cell line, HL60, frequently used to assess neutrophil function, was grown in serum-free medium.ResultsHL60 cells released acetaldehyde and hexanaldehyde in a time-dependent manner. The mean ± SD concentration of acetaldehyde in the headspace above the cultured cells following 4-, 24- and 48-h incubation was 157 ± 13 ppbv, 490 ± 99 ppbv, 698 ± 87 ppbv. For hexanaldehyde these values were 1 ± 0.3 ppbv, 8 ± 2 ppbv, and 11 ± 2 ppbv. In addition, our experimental system permitted us to identify confounding trace gas contaminants such as styrene.ConclusionThis study demonstrates that human immune cells known to mimic the function of innate immune cells, like neutrophils, produce volatile gases that can be measured in vitro in trace amounts.

Ratings of Perceived Exertion During Aerobic Exercise in Multiple Sclerosis

OBJECTIVE To compare ratings of perceived exertion (RPEs) during aerobic exercise in people with multiple sclerosis (MS) and control participants. DESIGN Prospective experimental study. SETTING An exercise testing laboratory. PARTICIPANTS Sedentary adults (n=12) with mild MS (Expanded Disability Status Scale score < or = 3) aged 30 to 45 years and sedentary age-matched and sex-matched controls (n=12). INTERVENTIONS All participants underwent a graded aerobic exercise test on a cycle ergometer with breath-by-breath gas measurements and continuous heart rate monitoring. MAIN OUTCOME MEASURES After completing the Modified Fatigue Impact Scale, participants rated their effort sense every 30 seconds during exercise using the modified Borg 10-point scale. RESULTS The 2 study groups showed similar baseline characteristics except for higher fatigue scores in the MS group. There were no significant differences for any fitness measure, including oxygen cost slope (in VO(2) x min(-1) x W(-1)), VO(2), or work rate during exercise. Neither heart rate nor RPE--measured at 25%, 50%, 75%, and 100% of VO(2)peak--differed between groups. CONCLUSIONS Despite greater reported fatigue levels, participants with MS showed similar RPE and physiologic responses to submaximal and maximal exercise compared with controls. In MS, the Borg 10-point scale may help improve evidence-based exercise prescriptions, which otherwise may be limited by fatigue, motor impairment, heat sensitivity, or autonomic dysfunction.

Brief bout of exercise alters gene expression in peripheral blood mononuclear cells of early- and late-pubertal males.

Peripheral blood mononuclear cells (PBMCs) are stimulated by exercise and contribute not only to host defense, but also to growth, repair, and disease pathogenesis. Whether PBMC gene expression is altered by exercise in children is not known. Ten early pubertal boys (8–12 y) and 10 late pubertal boys (15–18 y) performed ten 2-min bouts of strenuous, constant work rate exercise with 1-min rest intervals. PBMCs were isolated before and after exercise and microarray (Affymetrix U133 + 2 chips) analyzed. Statistical criterion to identify gene expression changes was less than 5% false discovery rate (FDR) with 95% confidence interval. One thousand two hundred forty-six genes were altered in older boys (517 up, 729 down), but only 109 were altered in the younger group (79 up, 30 down). In older boys, 13 gene pathways (using Expression Analysis Systematic Explorer, p < 0.05) were found (e.g. natural killer cell cytotoxicity, apoptosis). Epiregulin gene expression (EREG, a growth factor involved in wound healing) increased in older boys. In older boys exercise altered genes such as TBX21, GZMA, PGTDR, and CCL5 also play roles in pediatric inflammatory diseases like asthma. Sixty-six genes were changed significantly in both groups. The pattern of PBMC gene expression suggests the initiation of an immunologic “danger” signal associated with a sudden change in energy expenditure.

The effect of brief exercise on circulating CD34+ stem cells in early and late pubertal boys.

We tested the hypothesis that exercise could stimulate CD34+ peripheral blood hematopoietic stem cells (PBSC) in children. Fourteen early pubertal boys (EP, age 10.3 ± 0.3 y) and 13 late pubertal boys (LP, age 16.5 ± 0.4 y) performed 20 min of moderate-to-vigorous cycle ergometer exercise. Blood was drawn before and after exercise. Cells were stained for surface CD34+. Plasma granulocyte colony stimulating factor (G-CSF), Fms-like tyrosine kinase-3 (FLT-3), and stromal cell-derived factor-1 (SDF-1) were measured using ELISA. Exercise substantially increased PBSC (in EP from 112 ± 21 to 182 ± 30 cells/μL, p = 0.0007; in LP from 63 ± 8 to 152 ± 21, p = 0.0008), and to a smaller extent FLT-3 (in EP from 98 ± 5 to 110 ± 6 pg/mL, p < 0.0001; in LP from 73 ± 6 to 92 ± 6, p < 0.0001) and G-CSF (in EP from 26 ± 4 to 29 ± 4 pg/mL, p < 0.0001; in LP from 14 ± 1 to 18 ± 1, p < 0.0001). Baseline levels of PBSC, FLT-3, and G-CSF were significantly higher in EP. Exercise increased SDF-1α only in LP, and the FLT-3 increase was greater in LP than EP. Brief exercise affects PBSC and PBSC mediators in children.

Role of intradermal skin tests in the evaluation of clinically relevant respiratory allergy assessed using patient history and nasal challenges

BACKGROUND Skin testing, correlated with patient history, is the accepted method of identifying clinically relevant aeroallergen sensitivity. Traditionally, intradermal tests are believed to be more sensitive in identifying aeroallergen sensitivity than the epicutaneous and percutaneous methods. Therefore, many allergy practitioners use the epicutaneous or percutaneous method first and, if the results are negative, follow up with intradermal tests. OBJECTIVES To compare the epicutaneous, percutaneous, and intradermal methods to determine their sensitivity to patient history and to evaluate the value of intradermal tests when epicutaneous and percutaneous test results are negative. METHODS Participants were evaluated for rhinoconjunctivitis symptoms and then were skin tested using the prick and Multi-Test II (MTII) methods. Intradermal tests were performed when prick and MTII test results were negative to an aeroallergen. Participants with negative prick and MTII test results and corresponding positive intradermal test results underwent nasal challenges with evaluation by anterior rhinomanometry. RESULTS Compared with patient history, average sensitivity for MTII was 77% and for the prick method was 62%. When MTII results were negative, 17% of intradermal tests corresponded with probable patient histories of allergy but none with positive nasal challenge results. Nasal challenge results were similar to those of the negative control group and significantly different from those of the positive control group (P < .001). CONCLUSIONS The MTII tests are more sensitive and equally specific compared with the prick method. When MTII results are negative, positive intradermal test results are unlikely to identify clinically relevant aeroallergen sensitivity. Routine performance of intradermal tests when MTII results are negative is likely to be of low clinical yield.

Do circulating leucocytes and lymphocyte subtypes increase in response to brief exercise in children with and without asthma

Background: Exercise can alter health in children in both beneficial (eg reduced long-term risk of atherosclerosis) and adverse (eg exercise-induced asthma) ways. The mechanisms linking exercise and health are not known, but may rest, partly, on the ability of exercise to increase circulating immune cells. Little is known about the effect of brief exercise, more reflective of naturally occurring patterns of physical activity in children, on immune cell responses. Objectives: To determine whether (1) a 6-min bout of exercise can increase circulating inflammatory cells in healthy children and (2) the effect of brief exercise is greater in children with a history of asthma. Methods: Children with mild–moderate persistent asthma and age-matched controls (n = 14 in each group, mean age 13.6 years) performed a 6-min bout of cycle-ergometer exercise. Spirometry was performed at baseline and after exercise. Blood was drawn before and after exercise, leucocytes were quantified and key lymphocyte cell surface markers were assessed by flow cytometry. Results: Exercise decreased spirometry only in children with asthma, but increased (p<0.001) most types of leucocytes (eg lymphocytes (controls, mean (SD) 1210 (208) cells/μl; children with asthma, 1119 (147) cells/μl) and eosinophils (controls, 104 (22) cells/μl; children with asthma, 88 (20) cells/μl)) to the same degree in both groups. Similarly, exercise increased T helper cells (controls, 248 (60) cells/μl; children with asthma, 232 (53) cells/μl) and most other lymphocyte subtypes tested. By contrast, although basophils (16 (5) cells/μl) and CD4+ CD45RO+ RA+ lymphocytes (19 (4) cells/μl) increased in controls, no increase in these cell types was found in children with asthma. Conclusions: Exercise increased many circulating inflammatory cells in both children with asthma and controls. Circulating inflammatory cells did increase in children with asthma, but not to a greater degree than in controls. In fact, basophils and T helper lymphocyte memory transition cells did not increase in children with asthma, whereas they did increase in controls. Even brief exercise in children and adolescents robustly mobilises circulating immune cells.

Dynamic Interactions of Gas Exchange, Body Mass, and Progressive Exercise in Children

PURPOSE Cardiopulmonary exercise testing (CPET) is increasingly used as a biomarker of fitness in children. Maximal or peak values remain the most common variables obtained in CPET, but these physiologically challenging high-intensity work rates (WR) are often not achieved. We hypothesized that interactions of gas exchange, heart rate (HR), and WR CPET variables (slopes) could yield useful mechanistic and clinical insights that might enhance the clinical utility of CPET in children. We further hypothesized that the dependence of the slope on body mass could be predicted by the first-principle analysis of body size and physiological response. METHODS One hundred and sixty-nine healthy participants (8-18 yr old, body mass index <95th percentile, 82 females) underwent dual x-ray absorptiometry scan to estimate lean body mass (LBM) and performed a ramp-type progressive cycle ergometry exercise protocol with a breath-by-breath measurement of gas exchange. Linear regression was used to calculate the slopes among VO2, VCO2, VE, HR, and WR. RESULTS ΔWR/ΔHR (r = 0.87) and ΔVO2/ΔHR (r = 0.96) were strongly correlated with VO2peak, whereas ΔVO2/ΔWR (r = 0.42) and ΔVE/ΔVCO2 (r = -0.51) were mildly correlated with peak values. LBM was more highly correlated with those slopes predicted to be body size dependent (P < 0.0001) compared with total body mass. CONCLUSIONS The data largely supported our original hypotheses. Unlike peak or maximal values, which are derived from no more than a few data points at the end of a progressive exercise test, the CPET slopes were calculated from a much larger data set obtained throughout the test. An analysis of these slopes might ultimately prove useful clinically and in research studies when peak values are not achieved.