Littérature scientifique sur le sujet « Physical hypoactivity »

Gut microbiota, a major contributor to human health, is influenced by physical activity and diet, and displays a functional cross-talk with skeletal muscle. Conversely, few data are available on the impact of hypoactivity, although sedentary lifestyles are widespread and associated with negative health and socio-economic impacts. The study aim was to determine the effect of Dry Immersion (DI), a severe hypoactivity model, on the human gut microbiota composition. Stool samples were collected from 14 healthy men before and after 5 days of DI to determine the gut microbiota taxonomic profiles by 16S metagenomic sequencing in strictly controlled dietary conditions. The α and β diversities indices were unchanged. However, the operational taxonomic units associated with the Clostridiales order and the Lachnospiraceae family, belonging to the Firmicutes phylum, were significantly increased after DI. Propionate, a short-chain fatty acid metabolized by skeletal muscle, was significantly reduced in post-DI stool samples. The finding that intestine bacteria are sensitive to hypoactivity raises questions about their impact and role in chronic sedentary lifestyles.

Extremely low frequency electromagnetic field (ELF-EMF) exists widely in public and occupational environments. However, its potential adverse effects and the underlying mechanism on nervous system, especially behavior are still poorly understood. In this study, zebrafish embryos (including a transfected synapsin IIa (syn2a) overexpression plasmid) at 3 h post-fertilization (hpf) were exposed to a 50-Hz magnetic field (MF) with a series of intensities (100, 200, 400 and 800 μT, respectively) for 1 h or 24 h every day for 5 days. Results showed that, although MF exposure did not affect the basic development parameters including hatching rate, mortality and malformation rate, yet MF at 200 μT could significantly induce spontaneous movement (SM) hypoactivity in zebrafish larvae. Histological examination presented morphological abnormalities of the brain such as condensed cell nucleus and cytoplasm, increased intercellular space. Moreover, exposure to MF at 200 μT inhibited syn2a transcription and expression, and increased reactive oxygen species (ROS) level as well. Overexpression of syn2a could effectively rescue MF-induced SM hypoactivity in zebrafish. Pretreatment with N-acetyl-L-cysteine (NAC) could not only recover syn2a protein expression which was weakened by MF exposure, but also abolish MF-induced SM hypoactivity. However, syn2a overexpression did not affect MF-increased ROS. Taken together, the findings suggested that exposure to a 50-Hz MF inhibited spontaneous movement of zebrafish larvae via ROS-mediated syn2a expression in a nonlinear manner.

Weight control is dependent on energy balance. Reduced energy expenditure (EE) associated with decreased physical activity is suggested to be a major underlying cause in the increasing prevalence of weight gain and obesity. Therefore, a better understanding of the biological determinants involved in the regulation of physical activity is essential. To facilitate interpretation in humans, it is helpful to consider the evidence from animal studies. This review focuses on animal studies examining the biological determinants influencing activity and potential implications to human. It appears that physical activity is influenced by a number of parameters. However, regardless of the parameter involved, body weight appears to play an underlying role in the regulation of activity. Furthermore, the regulation of activity associated with body weight appears to occur only after the animal achieves a critical weight. This suggests that activity levels are a consequence rather than a contributor to weight control. However, the existence of an inverse weight-activity relationship remains inconclusive. Confounding the results are the multifactorial nature of physical activity and the lack of appropriate measuring devices. Furthermore, many determinants of body weight are closely interlocked, making it difficult to determine whether a single, combination, or interaction of factors is important for the regulation of activity. For example, diet-induced obesity, aging, lesions to the ventral medial hypothalamus, and genetics all produce hypoactivity. Providing a better understanding of the biological determinants involved in the regulation of activity has important implications for the development of strategies for the prevention of weight gain leading to obesity and subsequent morbidity and mortality in the human population.

The human gut microbiota is currently the focus of converging interest in many diseases and sports performance. This review presents gut microbiota as a real “orchestra conductor” in the host’s physio(patho)logy due to its implications in many aspects of health and disease. Reciprocally, gut microbiota composition and activity are influenced by many different factors, such as diet and physical activity. Literature data have shown that macro- and micro-nutrients influence gut microbiota composition. Cumulative data indicate that gut bacteria are sensitive to modulation by physical activity, as shown by studies using training and hypoactivity models. Sports performance studies have also presented interesting and promising results. Therefore, gut microbiota could be considered a “pivotal” organ for health and sports performance, leading to a new concept: the nutrition-microbiota-physical activity triad. The next challenge for the scientific and medical communities is to test this concept in clinical studies. The long-term aim is to find the best combination of the three elements of this triad to optimize treatments, delay disease onset, or enhance sports performance. The many possibilities offered by biotic supplementation and training modalities open different avenues for future research.

Arsenic exposure has been associated with sensory, motor, memory, and learning alterations in humans and alterations in locomotor activity, behavioral tasks, and neurotransmitters systems in rodents. In this study, CD1 mice were exposed to 0.5 or 5.0 mg As/L of drinking water for 6 months. Locomotor activity, aggression, interspecific behavior and physical appearance, monoamines levels, and expression of the messenger for dopamine receptors D1 and D2 were assessed. Arsenic exposure produced hypoactivity at six months and other behaviors such as rearing and on-wall rearing and barbering showed both increases and decreases. No alterations on aggressive behavior or monoamines levels in striatum or frontal cortex were observed. A significant decrease in the expression of mRNA for D2 receptors was found in striatum of mice exposed to 5.0 mg As/L. This study provides evidence for the use of dopamine receptor D2 as potential target of arsenic toxicity in the dopaminergic system.

One aspect of reproducibility in preclinical research that is frequently overlooked is the physical condition in which physiological, pharmacological, or behavioural recordings are conducted. In this study, the physical conditions of mice were altered through the attachments of wireless electrophysiological recording devices (Neural Activity Tracker-1, NAT-1). NAT-1 devices are miniaturised multichannel devices with onboard memory for direct high-resolution recording of brain activity for >48 h. Such devices may limit the mobility of animals and affect their behavioural performance due to the added weight (total weight of approximately 3.4 g). The mice were additionally treated with saline (control), N-methyl-D-aspartate (NMDA) receptor antagonist MK801 (0.85 mg/kg), or the muscarinic acetylcholine receptor blocker scopolamine (0.65 mg/kg) to allow exploration of the effect of NAT-1 attachments in pharmacologically treated mice. We found only minimal differences in behavioural outcomes with NAT-1 attachments in standard parameters of locomotor activity widely reported for the open field test between the drug treatments. Hypoactivity was globally observed as a consistent outcome in the MK801-treated mice and hyperactivity in scopolamine groups regardless of NAT-1 attachments. These data collectively confirm the reproducibility for combined behavioural, pharmacological, and physiological endpoints even in the presence of lightweight wireless data loggers. The NAT-1 therefore constitutes a pertinent tool for investigating brain activity in, e.g., drug discovery and models of neuropsychiatric and/or neurodegenerative diseases with minimal effects on pharmacological and behavioural outcomes.

Objective. Proinflammatory activity has been suggested as one of the psychophysiological mechanisms responsible for the health risks associated with stress and mood disorders. There have been limited studies evaluating central immune and hypothalamic— pituitary—adrenal (HPA) axis responses to experimental stress in healthy women. The current study compared, under a controlled condition, the baseline measures and biological and psychological responses to a physical stressor (lumbar puncture [LP]) of healthy women who exhibited an abnormal serum cortisol response (nonresponders [NRs]) to the LP to those of normal controls (responders [Rs]), allowing assessment of stress responsivity and the functional integrity of the feedback system of the HPA axis, sympathetic nervous system (SNS), and neuroimmune axis. Method. Serum adrenocorticotropic hormone (ACTH), cortisol, interleukin (IL)-6, IL-1sR, and central IL-1β, IL-6, norepineprhine (NE), corticotropin-releasing factor (CRF), and affective states (using the Stress Symptom Rating Questionnaire) were measured in five NRs and seven Rs. Results. Compared with NR subjects, Rs had significantly higher levels of ACTH and central IL-1β, higher ratings of attention, and lower perceived stress and anxiety. There were no differences between the groups in serum cortisol, IL-6, or IL-1sR or in central IL-6, NE, and CRF. Conclusions. Women with significantly elevated IL-1β (NRs) responded to an extreme physical stressor with an attenuated HPA system and abnormal subjective ratings compared to healthy women with lower values of central IL-1β. These findings support the suppression of the effects of HPA-axis cortisol on proinflammatory cytokine production. It is possible that these differences in the psychoneuroimmunological profiles of NRs will lead to increased psychobiological vulnerability and predict future health risk.

Pierpont syndrome is a rare and recently described multiple congenital anomaly syndrome, classically characterized by global developmental delay, distinctive facial dysmorphic features, and abnormal fat distribution in distal limbs. Only few cases were previously documented. We report a case of a term male neonate admitted to the neonatal intensive care unit because of feeding difficulties. Intrauterine growth restriction, microcephaly, and bilateral equinovarus foot were diagnosed in the second trimester, and prenatal array comparative genomic hybridization showed no abnormality. Physical examination revealed bilateral flexion deformities of wrists, elbows, knees and clubfoot, large hands and feet, deep palmar and plantar grooves, and calcaneo-plantar fat pads. Craniofacial dysmorphism, axial hypotonia, and hypoactivity were also observed. Due to the presence of congenital and non-progressive joint contractures, arthrogryposis multiplex congenita (AMC) was considered. A comprehensive diagnostic workup, including a Next Generation Sequencing target panel, was performed but did not establish a diagnosis. The clinical exome identified an heterozygous pathogenic variant in the TBL1XR1 gene (NM_001321194.1: c.1337A>G, p.[Tyr446Cys]), allowing Pierpont syndrome diagnosis. Our case stands out for reporting the novel AMC presentation in a Pierpont syndrome newborn. The broader and precocious genetic testing proved to be an essential clarifying diagnostic tool. Our patient supports the relation between the p.Tyr446Cys sequence variant in TBL1XR1 gene with this rare syndrome, reinforcing its association with a distinctive and recognizable phenotype, as well as expanding its clinical features to include AMC.

L'enfance est une période de construction de l'organisme durant laquelle des interactions avec l'environnement et une activité physique régulière sont nécessaires à la maturation des réseaux neuronaux. Ainsi, un dialogue constant entre le muscle et le cerveau assure le développement harmonieux des fonctions motrices. Cependant, une activité sensorimotrice atypique durant l'enfance (qu'elle soit due à un manque d'activité physique, à des troubles neurodéveloppementaux ou à des situations pathologiques telles qu'un alitement prolongé) perturbe le dialogue muscle - cerveau et un cycle délétère et auto-entretenu s'installe : l'activité sensorimotrice atypique génère des mouvements anormaux/atypiques qui induisent une rétroaction somatosensorielle atypique vers le système nerveux central immature. Ceci entraine une désorganisation des circuits sensorimoteurs et la commande motrice se trouve modifiée. Les propriétés musculaires sont affectées, ce qui impacte la réalisation du mouvement et renforce la production de mouvements anormaux. L'ensemble de ces éléments pourra affecter au final la vie future de l'enfant. Toutefois, les conséquences d'une activité sensorimotrice atypique sur le développement du système neuromusculaire restent parcellaires à ce jour et requièrent un intérêt particulier.L'objectif principal de cette thèse est d'avancer dans la compréhension des effets de la restriction sensorimotrice sur le dialogue muscle - cerveau. Pour répondre à cette problématique, des études ont été menées à partir d'un modèle animal de RSM qui consiste à immobiliser les pattes postérieures des ratons du jour postnatal 1 (P1) à P28. Il reproduit un phénotype moteur proche de celui décrit chez les patients atteints de trouble développemental de la coordination (modifications musculosquelettiques durables, déficits locomoteurs, hyper-réflexie spinale...).Une première étude s'est intéressée aux effets de la RSM sur la maturation du système neuromusculaire à travers l'analyse des réflexes neurodéveloppementaux, qui dépendent étroitement du développement des muscles et représentent en outre des indicateurs fiables du développement neurologique et comportemental. Outre la voie neuronale sensorimotrice, le muscle et le cerveau communiquent également par voie endocrinienne, et notamment via les myokines, des molécules sécrétées par les muscles squelettiques en réponse à l'activité physique. Parmi ces myokines, l'intérêt s'est porté sur l'irisine et sur son précurseur (FNDC5). L'irisine est considérée comme un véritable médiateur des effets bénéfiques de l'exercice au niveau du système nerveux central, où elle induit notamment l'expression de BDNF. Ainsi, dans une seconde étude, nous avons quantifié les taux de myokines (irisine) dans le muscle et le cerveau. Enfin, nous avons voulu déterminer si la RSM précoce (de P1 à P28) pouvait avoir des effets fonctionnels à long terme (P60-P90).Ces études démontrent que la RSM induit 1) une diminution du poids corporel ainsi qu'une atrophie des muscles des pattes postérieures, qui touche préférentiellement le soleus ; 2) un retard dans le développement moteur et l'apparition des principaux réflexes neurodéveloppementaux ; 3) une augmentation de FNDC5/irisine dans le soleus, le plasma et certains structures cérébrales, sans augmentation de BDNF et 4) des effets à long terme et notamment une altération des performances motrices.Ainsi, la RSM et les faibles interactions avec l'environnement au cours du développement entrainent une altération de la maturation du système neuromusculaire. L'augmentation de FNDC5/irisine dans le soleus suggère l'existence d'un mécanisme adaptatif qui se mettrait en place afin de réduire l'impact de la RSM. Enfin, les conséquences à P60-P90 de la RSM soutiennent l'idée qu'il existe des périodes critiques, de « programmation », pendant lesquelles des facteurs négatifs tels que l'inactivité physique peuvent entrainer des conséquences à court et à long termes
Childhood is a period of construction of the organism, during which interactions with the environment and regular physical activity are necessary for the maturation of neuronal networks. Thus, a constant dialogue between muscle and brain ensures the harmonious development of motor functions. However, atypical sensorimotor activity (whether due to lack of physical activity, neurodevelopmental disorders or pathological situations such as prolonged bed rest) disrupts the muscle-brain dialogue and a deleterious and self-perpetuating cycle is established: atypical sensorimotor activity generates abnormal/atypical movements which induce atypical somatosensory feedback to the immature central nervous system. This leads to disorganization of sensorimotor circuits and motor control is altered. Muscle properties are affected, which impacts movement and reinforces the production of abnormal movements. All of these elements could ultimately affect the child's future life. However, the consequences of atypical sensorimotor activity on the development of the neuromuscular system remain fragmentary to date and deserve special interest.The main objective of this thesis is to improve our understanding of the effects of sensorimotor restriction (SMR) on muscle-brain dialogue. To address this issue, studies were carried out using an animal model of SMR, which consists of immobilizing hindlimbs of the pups from postnatal day 1 (PND1) to PND28. This model reproduces a motor phenotype close to that described in patients with developmental coordination disorder (long-lasting musculoskeletal changes, locomotor deficits, spinal hyperreflexia, etc.).A first study focused on the effects of SMR on the maturation of the neuromuscular system through analysis of neurodevelopmental reflexes which are closely related on muscle development and are also reliable indicators of neurological and behavioral development. In addition to the sensorimotor neuronal pathway, muscle and brain also communicate via the endocrine pathway, especially through myokines, molecules secreted by skeletal muscles in response to physical activity. Among these myokines, interest has focused on irisin and its precursor (FNDC5). Irisin is considered to be a true mediator of the beneficial effects of exercise in the central nervous system, where it notably induces BDNF expression. Thus, in a second study, we quantified myokines (irisin) levels in muscle dans brain. Finally, we wanted to determine whether early RSM (from P1 to P28) could have long-term functional effects (P60-P90).These studies demonstrate that SMR induces 1) a decrease in body weight and atrophy of hindlimb muscles, preferentially affecting the soleus; 2) a delay in motor development and in the appearance of the main neurodevelopmental reflexes; 3) an increase in FNDC5/irisin in soleus, plasma and some brain structures, without any change for BDNF and 4) long-term effects including motor performance impairment.Thus, SMR and weak interactions with the environment during development lead to impaired maturation of neuromuscular system. The increase in FNDC5/irisin in the soleus suggests the existence of an adaptive mechanism that could reduce impact of SMR. Finally, the effects of SMR at P60-P90 support the idea that there are critical, “programming” periods, during which negative factors such as physical inactivity can lead to short- and long-term consequences

Title: Changes in the locomotor apparatus due to an injury with permanent consequences Objectives: The aime of the diploma thesis is to define changes in motor system of chosen persons after injury using classic methods often used in physiotherapy. In addition, it presents some of the options of therapy and self-therapy, education and reeducation in the area of the client's behavior towards his health. Methods: This diploma thesis is formed with use of qualitative research. It is a pilot study focused on five persons with permanent consequences in motor system. The content of examination is an anamnesis, an ori- entational static examination, an examination of shortened muscles, en examination of muscle strenght, an evaluation of posture and body distances. All above were meassured every 3 - 4 months, when the changes in body posture due to premanent consequences are ob- served. Results: All data are processed using tables and graphs. Results has shown an improvement in all clients in different degree. Improvement in postu- re and activation of coremuscles. Excercises also improved stere- otype in breathing. Study has also shown importance of clienťs active cooperation to achieve the best results. Keywords: Locomotor apparatus, injury, permanent consequences, physical activities, hypoactivity, type...