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1.
Nature ; 629(8011): 417-425, 2024 May.
Article in English | MEDLINE | ID: mdl-38658748

ABSTRACT

Cancer-specific TCF1+ stem-like CD8+ T cells can drive protective anticancer immunity through expansion and effector cell differentiation1-4; however, this response is dysfunctional in tumours. Current cancer immunotherapies2,5-9 can promote anticancer responses through TCF1+ stem-like CD8+ T cells in some but not all patients. This variation points towards currently ill-defined mechanisms that limit TCF1+CD8+ T cell-mediated anticancer immunity. Here we demonstrate that tumour-derived prostaglandin E2 (PGE2) restricts the proliferative expansion and effector differentiation of TCF1+CD8+ T cells within tumours, which promotes cancer immune escape. PGE2 does not affect the priming of TCF1+CD8+ T cells in draining lymph nodes. PGE2 acts through EP2 and EP4 (EP2/EP4) receptor signalling in CD8+ T cells to limit the intratumoural generation of early and late effector T cell populations that originate from TCF1+ tumour-infiltrating CD8+ T lymphocytes (TILs). Ablation of EP2/EP4 signalling in cancer-specific CD8+ T cells rescues their expansion and effector differentiation within tumours and leads to tumour elimination in multiple mouse cancer models. Mechanistically, suppression of the interleukin-2 (IL-2) signalling pathway underlies the PGE2-mediated inhibition of TCF1+ TIL responses. Altogether, we uncover a key mechanism that restricts the IL-2 responsiveness of TCF1+ TILs and prevents anticancer T cell responses that originate from these cells. This study identifies the PGE2-EP2/EP4 axis as a molecular target to restore IL-2 responsiveness in anticancer TILs to achieve cancer immune control.


Subject(s)
CD8-Positive T-Lymphocytes , Cell Proliferation , Dinoprostone , Lymphocytes, Tumor-Infiltrating , Neoplasms , Stem Cells , Tumor Escape , Animals , Female , Humans , Male , Mice , CD8-Positive T-Lymphocytes/cytology , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Cell Differentiation , Cell Line, Tumor , Dinoprostone/metabolism , Disease Models, Animal , Hepatocyte Nuclear Factor 1-alpha/metabolism , Interleukin-2 , Lymph Nodes/cytology , Lymph Nodes/immunology , Lymphocytes, Tumor-Infiltrating/cytology , Lymphocytes, Tumor-Infiltrating/immunology , Lymphocytes, Tumor-Infiltrating/metabolism , Mice, Inbred C57BL , Neoplasms/immunology , Neoplasms/prevention & control , Receptors, Prostaglandin E, EP2 Subtype/deficiency , Receptors, Prostaglandin E, EP2 Subtype/metabolism , Receptors, Prostaglandin E, EP4 Subtype/deficiency , Receptors, Prostaglandin E, EP4 Subtype/metabolism , Signal Transduction , Stem Cells/cytology , Stem Cells/immunology , Stem Cells/metabolism , Tumor Escape/immunology
2.
Cancer Immunol Immunother ; 73(6): 100, 2024 Apr 17.
Article in English | MEDLINE | ID: mdl-38630291

ABSTRACT

In multiple myeloma (MM), B cell maturation antigen (BCMA)-directed CAR T cells have emerged as a novel therapy with potential for long-term disease control. Anti-BCMA CAR T cells with a CD8-based transmembrane (TM) and CD137 (41BB) as intracellular costimulatory domain are in routine clinical use. As the CAR construct architecture can differentially impact performance and efficacy, the optimal construction of a BCMA-targeting CAR remains to be elucidated. Here, we hypothesized that varying the constituents of the CAR structure known to impact performance could shed light on how to improve established anti-BCMA CAR constructs. CD8TM.41BBIC-based anti-BCMA CAR vectors with either a long linker or a short linker between the light and heavy scFv chain, CD28TM.41BBIC-based and CD28TM.CD28IC-based anti-BCMA CAR vector systems were used in primary human T cells. MM cell lines were used as target cells. The short linker anti-BCMA CAR demonstrated higher cytokine production, whereas in vitro cytotoxicity, T cell differentiation upon activation and proliferation were superior for the CD28TM.CD28IC-based CAR. While CD28TM.CD28IC-based CAR T cells killed MM cells faster, the persistence of 41BBIC-based constructs was superior in vivo. While CD28 and 41BB costimulation come with different in vitro and in vivo advantages, this did not translate into a superior outcome for either tested model. In conclusion, this study showcases the need to study the influence of different CAR architectures based on an identical scFv individually. It indicates that current scFv-based anti-BCMA CAR with clinical utility may already be at their functional optimum regarding the known structural variations of the scFv linker.


Subject(s)
Multiple Myeloma , Humans , Multiple Myeloma/therapy , B-Cell Maturation Antigen , Antibodies , CD28 Antigens , Cell- and Tissue-Based Therapy
3.
Front Public Health ; 12: 1333546, 2024.
Article in English | MEDLINE | ID: mdl-38510355

ABSTRACT

Introduction: The COVID-19 pandemic led to restrictions that prevented physical activity in public places. This study sought to conduct a comprehensive longitudinal analysis of how lockdown policies in an Arabian Gulf country influenced the patterns of physical activity during first wave. Methods: In a longitudinal study design, members of the ongoing "Step into health" community-based health promotion program who provided valid pedometer data from January to August 2020, covering pre, during and post-covid first wave period met the inclusion criteria. Results: 420 (76.7% men, 13.8% ≤40 years) were included in the study. Overall, significant decline in daily step counts was recorded (-1,130 ± SE302) after the implementation of lockdown policies (p < 0.001). When the restrictions were removed, the steps per day were still lower compared to pre-covid for men (-910 ± SE610, p = 0.017) and among individuals with normal BMI (-1,304 ± SE409, p = 0.004). The lockdown in Qatar did not significantly affect women and individuals with obesity who already had lower daily steps pre-covid. Discussion: The present study confirms immediate decline in daily steps imposed indirectly through the COVID-19 lockdown measures. Participants with higher physical activity levels pre-covid experienced significant decline in step count during and even after restrictions were uplifted.


Subject(s)
COVID-19 , Pandemics , Male , Humans , Female , Longitudinal Studies , Qatar/epidemiology , COVID-19/epidemiology , COVID-19/prevention & control , Communicable Disease Control , Exercise , Health Promotion
4.
Front Physiol ; 15: 1357172, 2024.
Article in English | MEDLINE | ID: mdl-38405123

ABSTRACT

Walking is the most accessible and common type of physical activity. Exercising at one's self-selected intensity could provide long-term benefits as compared to following prescribed intensities. The aim of this study was to simultaneously examine metabolic, perceptual, spatiotemporal and stability parameters at an absolute 3 km·h-1 speed range around the individual preferred walking speed (PWS). Thirty-four young sedentary adults (18 women) volunteered to walk at seven speeds relative to their PWS in 3-min trials interspaced with 3-min rest intervals. Results indicated a significant main effect of speed on all studied variables. While metabolic, perceptual and spatiotemporal values were sensitive to the smallest change in speed (i.e., 0.5 km·h-1), a significant increase in the rate of carbohydrate oxidation and decrease in %fat oxidation were only observed at speeds above PWS. Results also revealed significantly higher coefficients of variation for stride characteristics at speeds below PWS only. Moreover, analyses of best fit models showed a quadratic relationship between most variables and speed, with the exceptions of metabolic cost of transport, rating of perceived exertion and stride duration that changed exponentially with speed. PWS coincided with optimized mechanical efficiency, fuel oxidation and gait stability. This indicated that walking below PWS decreased both mechanical efficiency and stability of gait, while walking above PWS increased carbohydrate oxidation. Those factors seem to play an important role as determinants of PWS. We suggest that walking at PWS may provide benefits in terms of fat oxidation while optimizing gait stability.

5.
Br J Cancer ; 129(4): 696-705, 2023 09.
Article in English | MEDLINE | ID: mdl-37400680

ABSTRACT

BACKGROUND: In many situations, the therapeutic efficacy of CAR T cells is limited due to immune suppression and poor persistence. Immunostimulatory fusion protein (IFP) constructs have been advanced as a tool to convert suppressive signals into stimulation and thus promote the persistence of T cells, but no universal IFP design has been established so far. We now took advantage of a PD-1-CD28 IFP as a clinically relevant structure to define key determinants of IFP activity. METHODS: We compared different PD-1-CD28 IFP variants in a human leukemia model to assess the impact of distinctive design choices on CAR T cell performance in vitro and a xenograft mouse model. RESULTS: We observed that IFP constructs that putatively exceed the extracellular length of PD-1 induce T-cell response without CAR target recognition, rendering them unsuitable for tumour-specific therapy. IFP variants with physiological PD-1 length ameliorated CAR T cell effector function and proliferation in response to PD-L1+ tumour cells in vitro and prolonged survival in vivo. Transmembrane or extracellular CD28 domains were found to be replaceable by corresponding PD-1 domains for in vivo efficacy. CONCLUSION: PD-1-CD28 IFP constructs must mimic the physiological interaction of PD-1 with PD-L1 to retain selectivity and mediate CAR-conditional therapeutic activity.


Subject(s)
Immunotherapy, Adoptive , Leukemia , Humans , Mice , Animals , CD28 Antigens , Programmed Cell Death 1 Receptor , B7-H1 Antigen , Cell Line, Tumor
6.
J Immunother Cancer ; 11(5)2023 05.
Article in English | MEDLINE | ID: mdl-37208128

ABSTRACT

BACKGROUND: Melanoma is an immune sensitive disease, as demonstrated by the activity of immune check point blockade (ICB), but many patients will either not respond or relapse. More recently, tumor infiltrating lymphocyte (TIL) therapy has shown promising efficacy in melanoma treatment after ICB failure, indicating the potential of cellular therapies. However, TIL treatment comes with manufacturing limitations, product heterogeneity, as well as toxicity problems, due to the transfer of a large number of phenotypically diverse T cells. To overcome said limitations, we propose a controlled adoptive cell therapy approach, where T cells are armed with synthetic agonistic receptors (SAR) that are selectively activated by bispecific antibodies (BiAb) targeting SAR and melanoma-associated antigens. METHODS: Human as well as murine SAR constructs were generated and transduced into primary T cells. The approach was validated in murine, human and patient-derived cancer models expressing the melanoma-associated target antigens tyrosinase-related protein 1 (TYRP1) and melanoma-associated chondroitin sulfate proteoglycan (MCSP) (CSPG4). SAR T cells were functionally characterized by assessing their specific stimulation and proliferation, as well as their tumor-directed cytotoxicity, in vitro and in vivo. RESULTS: MCSP and TYRP1 expression was conserved in samples of patients with treated as well as untreated melanoma, supporting their use as melanoma-target antigens. The presence of target cells and anti-TYRP1 × anti-SAR or anti-MCSP × anti-SAR BiAb induced conditional antigen-dependent activation, proliferation of SAR T cells and targeted tumor cell lysis in all tested models. In vivo, antitumoral activity and long-term survival was mediated by the co-administration of SAR T cells and BiAb in a syngeneic tumor model and was further validated in several xenograft models, including a patient-derived xenograft model. CONCLUSION: The SAR T cell-BiAb approach delivers specific and conditional T cell activation as well as targeted tumor cell lysis in melanoma models. Modularity is a key feature for targeting melanoma and is fundamental towards personalized immunotherapies encompassing cancer heterogeneity. Because antigen expression may vary in primary melanoma tissues, we propose that a dual approach targeting two tumor-associated antigens, either simultaneously or sequentially, could avoid issues of antigen heterogeneity and deliver therapeutic benefit to patients.


Subject(s)
Antibodies, Bispecific , Melanoma , Humans , Mice , Animals , Antibodies, Bispecific/pharmacology , Antibodies, Bispecific/therapeutic use , T-Lymphocytes , Neoplasm Recurrence, Local , Antigens, Neoplasm
7.
Immunity ; 56(1): 143-161.e11, 2023 01 10.
Article in English | MEDLINE | ID: mdl-36630913

ABSTRACT

Although T cells can exert potent anti-tumor immunity, a subset of T helper (Th) cells producing interleukin-22 (IL-22) in breast and lung tumors is linked to dismal patient outcome. Here, we examined the mechanisms whereby these T cells contribute to disease. In murine models of lung and breast cancer, constitutional and T cell-specific deletion of Il22 reduced metastases without affecting primary tumor growth. Deletion of the IL-22 receptor on cancer cells decreases metastasis to a degree similar to that seen in IL-22-deficient mice. IL-22 induced high expression of CD155, which bound to the activating receptor CD226 on NK cells. Excessive activation led to decreased amounts of CD226 and functionally impaired NK cells, which elevated the metastatic burden. IL-22 signaling was also associated with CD155 expression in human datasets and with poor patient outcomes. Taken together, our findings reveal an immunosuppressive circuit activated by T cell-derived IL-22 that promotes lung metastasis.


Subject(s)
Interleukins , Neoplasms , Receptors, Virus , T-Lymphocytes, Helper-Inducer , Animals , Humans , Mice , Antigens, Differentiation, T-Lymphocyte/metabolism , Interleukins/genetics , Interleukins/metabolism , Killer Cells, Natural/metabolism , Neoplasms/metabolism , Protein Binding , T-Lymphocytes, Helper-Inducer/metabolism , Interleukin-22
8.
J Exerc Sci Fit ; 21(1): 14-19, 2023 Jan.
Article in English | MEDLINE | ID: mdl-36349302

ABSTRACT

Objective: The Lebanese Active Healthy Kids Work Group (LAHKWG) synthesized literature published on physical activity (PA) indicators among ages 5- to 17- year-olds, using a recommended harmonized process by the Active Healthy Kids Global Alliance (AHKGA), to explore Lebanon's performance since its previous report card publication. Methods: Peer reviewed literature, national surveys, and gray literature published since 2017, on 10 common AHKGA and two LAHKWG recommended indicators were examined. Common indicators included overall PA, organized sport and PA, active play, active transportation, community and environment, sedentary behaviors, physical fitness, family and peers, school, and government. LAHKWG recommended indicators were sleep and weight status. LAHKWG members reviewed 764 records, of which 28 were selected for full review. A grade was assigned for each indicator using AHKGA's grading rubric and established benchmarks on data from nationally representative samples for children and youth. Results: Data from one nationally representative sample were available for ages 13-17 years (i.e., no data <13 years). Five indicators received "Incomplete" (organized sport and PA; active Play; physical fitness; family and peers; community and environment); overall PA received a D-; active transportation and sleep received a D+; school and government received a D; sedentary behaviors received a C; and weight status received a B-. Conclusion: The LAHKWG strongly encourages stakeholders to take concrete actions towards prioritizing PA promotion at a national level especially in the education sector. Offering more quality PA opportunities for Lebanese children and youth will be beneficial for their physical and mental health in any context.

9.
Br J Cancer ; 127(12): 2175-2185, 2022 12.
Article in English | MEDLINE | ID: mdl-36266575

ABSTRACT

BACKGROUND: Chimeric antigen receptor (CAR) T cell therapy has been successfully translated to clinical practice for the treatment of B cell malignancies. The suppressive microenvironment of many malignancies is a bottleneck preventing treatment success of CAR T cells in a broader range of tumours. Among others, the immunosuppressive metabolite adenosine is present in high concentrations within many tumours and dampens anti-tumour function of immune cells and consequently therapeutic response. METHODS: Here, we present the impact of the selective adenosine A2A and A2B receptor antagonist AB928/etrumadenant on CAR T cell cytokine secretion, proliferation, and cytotoxicity. Using phosphorylation-specific flow cytometry, we evaluated the capability of AB928 to shield CAR T cells from adenosine-mediated signalling. The effect of orally administered AB928 on CAR T cells was assessed in a syngeneic mouse model of colon carcinoma. RESULTS: We found that immunosuppressive signalling in CAR T cells in response to adenosine was fully blocked by the small molecule inhibitor. AB928 treatment enhanced CAR T cell cytokine secretion and proliferation, granted efficient cytolysis of tumour cells in vitro and augmented CAR T cell activation in vivo. CONCLUSIONS: Together our results suggest that combination therapy with AB928 represents a promising approach to improve adoptive cell therapy.


Subject(s)
Neoplasms , T-Lymphocytes , Animals , Mice , Adenosine/pharmacology , Cytokines , Tumor Microenvironment
10.
Front Public Health ; 10: 927386, 2022.
Article in English | MEDLINE | ID: mdl-36199850

ABSTRACT

Purpose: Investigate adherence and retention to the "Step Into Health (SIH)" initiative (www.stepintohealth.qa [website access only available from within the State of Qatar]), a Qatari self-managed community-based health program, from 2012 to 2019. Methods: Participants (16,711; 16-80 years; 37% females, 34% Qatari) used a pedometer or smartphone application (app) to measure step count. Absolute adherence (ADH) and retention (RET) were calculated, with ADH (%) the ratio between number of days data and SIH enrollment length (RET). Linear Mixed Models identified differences in ADH between RET groups, main effects (i.e., sex, device, age, BMI, nationality) and interaction effects for ADH (RET entered as a covariate). Results: Average ADH and RET to SIH (irrespective of sex, age, device and BMI) was 50% (±31%), and 16% (±20%), respectively, with ADH differing significantly between RET groups (F = 460.2, p < 0.001). RET (as a covariate) revealed a significant main effect for device (F = 12.00, p < 0.001) and age (F = 4.31, p = 0.001) on ADH observed. There was a significant association between RET and sex (p < 0.001), device (p < 0.001), and age groups 16-25 y (p < 0.001), and 26-35 y (p < 0.001). There were no significant main effects for sex or BMI on ADH, and no interaction effects (p ≥ 0.21) observed. Conclusions: Follow-up data (e.g., interviews, focus groups, etc.) determining why differences in ADH and RET are observed appears prudent. To convert those that lapsed and/or abandoned SIH/PA into committed long-term PA adherers. This would be a first step to develop targeted public health promotions and initiatives to enhance health outcomes at a population level.


Subject(s)
Self-Management , Actigraphy , Female , Health Promotion , Humans , Male , Public Health , Qatar
11.
Article in English | MEDLINE | ID: mdl-33202549

ABSTRACT

We examined the relationships between body fat (BF) and field measures of physical fitness in adolescent handball players. Twenty nine players (age: 16.6 ± 1.72 years; body mass: 79.8 ± 17.0 kg; height: 1.70 ± 0.12 m; body fat: 27.7 ± 8.67%) from Qatar handball first league performed a series of anthropometric and fitness tests related to their performance in sprinting (i.e., 15 m and 30 m sprint), jumping (i.e., countermovement and squat jumps), throwing (i.e., 3 kg medicine ball seated front throw) and running (i.e., agility T-Half and Yo-Yo intermittent recovery level 1 tests). Significant differences between obese and non-obese groups, classified based on age-stratified %BF norms, were found, with the largest difference being attributed to aerobic performance on the Yo-Yo test. Results indicated no significant relationships between anthropometric variables and sprinting or jumping abilities. %BF predicted a significant 8-15% portion in running performances of agility and aerobic capacity, while the latter were mainly explained by body height and mass. %BF was the only and strongest predictor of throwing performance, being an important determinant of performance in handball. Optimizing %BF should be considered as a training and nutrition goal in order to improve sport performance.


Subject(s)
Athletic Performance , Adipose Tissue , Adolescent , Humans , Obesity , Physical Fitness , Qatar
12.
Nutrients ; 12(3)2020 Mar 14.
Article in English | MEDLINE | ID: mdl-32183393

ABSTRACT

Poor glycaemic control is associated with chronic life-threatening complications. This cross-sectional study examined whether there is an association between handgrip strength and glycaemic control among patients with diabetes. Data on 1058 participants aged 40 and older were collected from the National Health and Nutritional Examination Survey (NHANES). Muscle strength was assessed using a handgrip dynamometer, and glycaemic control was assessed using HbA1c. Handgrip strength was presented as age- and gender-specific quartiles, with participants in quartile 1 having the lowest handgrip strength and participants in quartile 4 having the highest handgrip strength. Logistic regression analyses were used to assess the association between handgrip strength and poor glycaemic control among participants with diabetes. Three models, each adjusted to include different variables, were employed. Odds ratio (OR) values revealed no association between handgrip strength and glycaemic control after adjusting for age, gender, and race in model 1. With further adjustment for sedentary activity, income-to-poverty ratio, education, and smoking, patients in quartile 4 of handgrip strength had 0.51 odds of poor glycaemic control (95% CI: 0.27-0.99). However, the reported association above vanished when further adjusted for insulin use (OR = 0.67; 95% CI: 0.35-1.28). In conclusion, findings may indicate an association between glycaemic control and muscle strength. This association may be altered by insulin use; further investigations are required.


Subject(s)
Diabetes Mellitus, Type 2 , Glycemic Control , Hand Strength , Models, Biological , Aged , Diabetes Mellitus, Type 1/blood , Diabetes Mellitus, Type 1/physiopathology , Diabetes Mellitus, Type 2/blood , Diabetes Mellitus, Type 2/physiopathology , Female , Glycated Hemoglobin/metabolism , Humans , Male , Middle Aged
13.
PLoS One ; 14(10): e0223359, 2019.
Article in English | MEDLINE | ID: mdl-31600266

ABSTRACT

BACKGROUND: Physical inactivity is high within the Qatari population, particularly within females, and school-based environments, contributing to increased morbidity and mortality. School-based physical activity (PA) outcomes may be mediated by physical self-concept. Low physical self-concept may negatively impact PA engagement, compromising childhood and adolescent physical fitness, which may translate into adulthood. Normative physical fitness data for the Qatari population is unavailable. Stratifying normative physical fitness appears prudent, to not only allow comparisons to be made worldwide, but enable informed decisions for public health policy and future interventions in the Qatari population. PURPOSE: To establish the physical fitness of young adults in Qatar, and examine differences between males and females for physical self-concept, and engagement in school-based and extra-curricular PA. METHOD: 186 (females n = 85) healthy participants [median (minimum-maximum) age: males = 21 (18-26), females = 21 (18-24) y; height: males = 1.74 (1.57-1.99), females = 1.61 (1.46-1.76) m; body mass: males = 71.9 (49.3-145.0), females = 56.8 (35.7-96.4) kg] completed the ALPHA-FIT test battery for adults (one leg stand, figure of eight run, handgrip strength, jump and reach, modified push-up, dynamic sit-up and 2 km walk), physical self-description questionnaire (measuring physical self-concept), and were asked to answer 'yes' or 'no' to whether they participated in school-based and extra-curricular PA. RESULTS: Data is reported as effect size; ±90% confidence limit. Males compared to females most likely performed better for dynamic sit-up (2.2; ±0.76), very likely better for the figure of eight run (0.86; ±0.42) and likely better for handgrip strength (2.1; ±0.75). Males likely had higher physical self-concept for coordination (0.78; ±0.37) and endurance (0.66; ±0.27) compared to females. There were no differences for school-based PA (p ≥ 0.78) or for extra-curricular PA for males (p ≥ 0.26) or females (p ≥ 0.21). CONCLUSION: The data suggests that the young Qatari adult population has variable, yet generally low, physical fitness traits compared to individuals worldwide, likely due to their low PA. The precise aetiology for this is not well documented, yet such data may be prudent to evidence-inform strategies to improve physical fitness through increased PA (synergistic relationship), given the strong association between physical activity/fitness and morbidity/mortality.


Subject(s)
Physical Fitness/physiology , Self Concept , Adolescent , Adult , Body Mass Index , Female , Hand Strength , Humans , Male , Qatar , Surveys and Questionnaires , Young Adult
14.
J Phys Act Health ; 16(6): 385-396, 2019 06 01.
Article in English | MEDLINE | ID: mdl-31023183

ABSTRACT

Background: Evidence on physical activity (PA) indicators for children and youth at a national level is necessary to improve multilevel support for PA behaviors. Lebanon's first Physical Activity Report Card for children and youth (2018) aimed to fill this gap. Methods: In line with the recommended methods of "Global Matrix 3.0," nationally representative data were retrieved from peer-reviewed manuscripts, national surveys, and government reports. In addition to adopting the 10 indicators of "Global Matrix 3.0," publications that discussed weight status were also retained. A grade was assigned for each indicator using a standard rubric: A = 80% to 100%, B = 60% to 79%, C = 40% to 59%, D = 20% to 39%, F = <20%, and INC = incomplete data. Results: Four indicators (active play, family and peers, community and environment, and physical fitness) received an "INC." Three indicators (overall PA, active transportation, and school) received a "D." Sedentary behaviors received a "C-." Weight status received a "C." Government received a "C+." Organized sport received an "F." Conclusions: PA participation among Lebanese children and youth is low. Stakeholders should aim to improve low PA indicators grades. Gaps in the literature also need to be filled to inform on the status of all indicators.


Subject(s)
Exercise/physiology , Health Policy , Health Promotion/methods , Physical Fitness/physiology , Adolescent , Body Weight , Child , Environment Design , Female , Humans , Lebanon , Male , Obesity , Peer Group , Play and Playthings , Schools , Sedentary Behavior , Sports/physiology
15.
Front Physiol ; 10: 265, 2019.
Article in English | MEDLINE | ID: mdl-30930799

ABSTRACT

This study investigated the mechanical efficiency (ME) and associated factors in obese, overweight, and normal-weight adolescent boys during incremental cycle exercise test to exhaustion. Forty-five sedentary adolescent boys (13-14 years old) were separated in three groups according to the percentage of fat mass as follows: 15 normal-weight (NW) (body fat: 16.0 ± 1.9%), 15 overweight (OW) (body fat: 24.0 ± 1.6%), and 15 obese (OB) (body fat: 31.0 ± 3.0%). All groups completed an incremental cycle exercise to exhaustion in which energy consumption (E, W), ME (%), lipid oxidation rate (LO, %), plasma epinephrine and norepinephrine concentrations were determined consecutively at rest and at three intensity levels corresponding to 50 and 75% of each participant's maximal heart rate (50%HRmax and 75%HRmax) and peak oxygen consumption ( V ˙ O2peak). During the incremental cycle exercise test, plasma epinephrine, and norepinephrine responses as well as ME determined at 50%HRmax, 75%HRmax, and at VO2peak stages were significantly lower in OB compared to NW and OW individuals (ps < 0.01). Multiple linear regressions showed that body weight (ß = -0.64, p < 0.001), energy consumption (ß = -0.24, p < 0.05) and lipid oxidation (ß = 0.69, p < 0.01) were significant predictors of ME at 50%HRmax. However, at 75%HRmax and V ˙ O2peak, significant predictors of ME were epinephrine (ß = 0.34, ß = 0.49, respectively, ps = 0.01), norepinephrine (ß = 0.26, ß = 0.60, respectively, ps < 0.05) and power output (ß = 0.62, ß = 0.71, respectively, ps < 0.01). These findings suggest that excess in body weight exerts a negative effect on ME at a low intensity by increasing energy consumption for obese and overweight adolescent boys, while at higher intensities (75%HRmax and VO2peak) the lower ME could be better explained by the lower power output and catecholamine responses that were attenuated among obese and overweight adolescent boys.

16.
Front Psychol ; 10: 252, 2019.
Article in English | MEDLINE | ID: mdl-30809177

ABSTRACT

Several studies have investigated the influence of perceiving colors on affective outcomes and/or performance. However, the effects of seeing colors on self-selected behaviors have received little attention from physiologists and psychologists. Therefore, the present study aimed at examining whether exposure to green and red environments could influence affective judgments, perception of effort, heart rate, and gait speeds when walking and running at a self-selected pace. Participants were randomly assigned to one of the three experimental conditions: Green, red, or white (neutral) environment. The experimental task consisted in a 20-min trial of either walking (Study 1) or running (Study 2) at the most comfortable speed on a treadmill surrounded by three large HD TV screens displaying specific properties of the studied colors. Study 1 revealed that walking in a green environment induced a significant reduction in heart rate values as compared to the red and white conditions although no differences in gait speed were found. This corroborates the calming and relaxing effect of green on the human organism. Study 2 showed that running in a green environment was associated with an increased level of perceived exertion at similar speeds (compared to other color conditions), while exposure to red induced a significant decrease in the level of tension. In both studies, the preferred gait speed was not affected by the colored environment which is discussed in relation to the energy-conservation principle. Furthermore, both studies showed that performing a 20-min walk or run at preferred pace presented beneficial mood changes. Implications of the effects of self-selected exercise under colored environments on human functioning are addressed in the discussion.

18.
Front Physiol ; 9: 1505, 2018.
Article in English | MEDLINE | ID: mdl-30410450

ABSTRACT

The present study aims (1) to evaluate ratings of perceived exertion (RPE) and corresponding intensities during a maximal graded cycling test and (2) to determine the effects of 6 weeks of supramaximal cycling exercise (SCE) intervention on RPE and associated physiological factors in young and older sedentary groups. Two healthy groups of 17 young adults [average (SD) age: 26.2 (2.4) year] and 13 older adults [average (SD) age: 54.5 (2.3) year] completed a 6-week SCE intervention on an ergocycle. Physiological values and RPE were collected across stages corresponding to ventilator thresholds 1 (VT1) and 2 (VT2) of the graded cycling test and 10 min following the end of test and during the six bouts of SCE. The relative intensity for both VT1 and VT2 were also objectively calculated based on the percent of maximal heart rate %HRmax and peak oxygen consumption % V ˙ O2peak. Before SCE intervention, RPE values were significantly higher for the older group compared to younger at VT1 [p < 0.01] and VT2 [p < 0.01], although both groups were working at similar relative intensities (% V ˙ O2). After 6 weeks of SCE, the older group's perceived effort values were normalized to the actual estimated ones and were similar to those observed in younger individuals. The intervention elicited physiological changes at rest and submaximal intensities, while no improvements were noted for both groups in aerobic fitness (i.e., V ˙ O2peak). For both groups, RPE decreases with SCE at 10 min following graded test correlated significantly to V ˙ O2 (r = 0.61, p < 0.01). Our study revealed that the initial over-estimation of the exertion levels found for the older sedentary group at the tested submaximal intensities was no longer present after 6 weeks of SCE training, therefore matching RPE values of the young group and those estimated by %HRmax and % V ˙ O2peak methods. Therefore, combining the RPE method with other commonly used methods of estimating exercise intensity is highly recommended for sedentary older adults to suitably monitor the exercise intensity.

19.
J Sports Med Phys Fitness ; 58(7-8): 1163-1170, 2018.
Article in English | MEDLINE | ID: mdl-28488826

ABSTRACT

BACKGROUND: The aim of the study was to compare the effects of high-intensity intermittent training (HIIT) versus small-sided games (SSG) in soccer on both the physiological responses and the mood state of players. METHODS: Sixteen professional soccer players took part in the study (age: 24.1±0.9 years). Testing of players was conducted on separate days in a randomized and counter-balanced order (each training session: 28 minutes: 4x4 minutes work with 3 minutes of passive recovery in-between). Effort: HIIT: intermittent 15-s runs at 110% maximal aerobic speed with 15 seconds of passive recovery in-between. SSG: 4 versus 4 players on a 25x35 meter pitch size with full-involvement play. Psychological responses before and after each training-session were assessed using the profile of mood-state (POMS: Tension, Depression, Anger, Vigor, Fatigue, and Confusion). The players' heart rate (HR) was continuously measured, whereas ratings of perceived exertion (RPE) and blood lactate concentration ([La]) were collected ~3-min after each training-session. RESULTS: HIIT and SSG showed no significant difference in HR, RPE and [La] responses. The HIIT compared with SSG resulted in: an increased total mood disturbance (P<0.001), tension (P<0.05), fatigue (P<0.01) and a decreased vigor (P<0.001). CONCLUSIONS: Both HIIT and SSG sessions induced similar physiological responses, in contrast, HIIT produced a mood disturbance while SSG ensured mood balance. Practitioners could choose between these two exercises according to the objective of their training, keeping in mind the mood-related advantages of the SSG shown in the present study.


Subject(s)
Affect/physiology , High-Intensity Interval Training/psychology , Physical Exertion/physiology , Soccer/psychology , Fatigue/psychology , Heart Rate/physiology , High-Intensity Interval Training/methods , Humans , Lactic Acid/blood , Male , Running/physiology , Soccer/physiology , Young Adult
20.
Front Hum Neurosci ; 11: 206, 2017.
Article in English | MEDLINE | ID: mdl-28491029

ABSTRACT

The present study aimed to compare various entropy measures to assess the dynamics and complexity of center of pressure (COP) displacements. Perturbing balance tests are often used in healthy subjects to imitate either pathological conditions or to test the sensitivity of postural analysis techniques. Eleven healthy adult subjects were asked to stand in normal stance in three experimental conditions while the visuo-kinesthetic input was altered. COP displacement was recorded using a force plate. Three entropy measures [Sample Entropy (SE), Multi-Scale Entropy (MSE), and Multivariate Multi Scale Entropy (MMSE)] describing COP regularity at different scales were compared to traditional measures of COP variability. The analyses of the COP trajectories revealed that suppression of vision produced minor changes in COP displacement and in the COP characteristics. The comparison with the reference analysis showed that the entropy measures analysis techniques are more sensitive in the incremented time series compared to the classical parameters and entropy measures of original time series. Non-linear methods appear to be an additional valuable tool for analysis of the dynamics of posture especially when applied on incremental time series.

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