Entraînement contre résistance et/ou supplémentation en antioxydants effets biochimiques, hématologiques sur la composition corporelle et des facteurs de risque des maladies cardiovasculaires chez des personnes âgées

Le vieillissement est associé à de nombreuses modifications de l'organisme, reliées à des altérations des facteurs de risque des maladies cardiovasculaires (MCV). Dans ce cadre, une masse maigre importante est considérée comme étant bénéfique pour la sensibilité à l'insuline. Ainsi, l'exercice contre résistance est jugé comme la stratégie la plus efficace pour permettre cette adaptation, surtout chez les adultes. Toutefois, chez les personnes âgées, les résultats ne sont pas toujours probants. Une raison sous-jacente empêchant l'adaptation optimale aux effets bénéfiques de ce type d'intervention serait l'augmentation des dommages oxydatifs avec le vieillissement. La supplémentation en antioxydants durant l'exercice contre résistance pourrait aider à l'obtention de meilleurs résultats. En effet, plusieurs études ont démontré qu'une supplémentation en antioxydants pouvait avoir des effets bénéfiques sur différents paramètres biochimiques et des dommages oxydatifs. Toutefois, l'effet des antioxydants en combinaison des exercices contre résistance sur l'ensemble de ces paramètres n'a toujours pas été vérifié chez les personnes âgées. Ainsi, la mise à disposition d'une nouvelle méthodologie pourrait s'avérer intéressante pour cette population. L'objet de cette thèse était de vérifier l'impact de ces interventions (supplémentation en antioxydants et exercices contre résistance) dans la prévention des facteurs de risque des MCV chez des personnes âgées. Les hypothèses avancées étaient que les personnes ayant participé à la combinaison des interventions (supplémentation en antioxydants et exercices musculaires) présentent une amélioration plus importante des paramètres biochimiques, de la composition corporelle et des facteurs de risque de MCV que les personnes ayant été soumises à l'une ou l'autre des interventions. Pour y répondre, 73 personnes âgées (59-73 ans, IMC[plus petit ou égal à]30kg/m[indice supérieur 2], sans incapacité physique ou médication influençant le métabolisme, non fumeur, buveur modéré, poids stable, pas d'ingestion d'antioxydant depuis un mois, non impliqué dans un programme d'exercices vigoureux) ont été recrutées et réparties aléatoirement dans 4 groupes (1 : témoin ; 2 : exercices contre résistance ; 3 : supplémentation en antioxydants ; 4 : exercices contre résistance + supplémentation en antioxydants). Différentes mesures ont été réalisées avant et après 6 mois d'intervention : composition corporelle, sensibilité à l'insuline, métabolisme de repos, apport alimentaire, profils biochimiques (lipidique et oxydatif) et profil hématologique. Nous avons tout d'abord constaté une amélioration des paramètres antioxydants sans diminution des facteurs prooxydants du stress oxydant dans le groupe d'interventions combinées. Toutefois, nous avons obtenu une augmentation significative de la masse maigre et une tendance à l'amélioration de la sensibilité à l'insuline dans le groupe d'interventions combinées, alors que les autres groupes sont demeurés inchangés. Cependant, il n'a pas été possible d'observer d'évolutions significatives des paramètres biochimiques ou hématologiques, si bien que les facteurs de risque de MCV ne se sont pas déteriorés dans cette population après 6 mois. L'ensemble de ces données permettent d'avancer que la supplémentation en antioxydants combinée aux exercices contre résistance chez des sujets âgés sains ont des effets bénéfiques et n'engendrent pas de détérioration de l'état de santé comparé aux sujets témoins : c'est un caractère non négligeable dans l'objectif du mieux vieillir. Dans ce cas, de nouvelles perspectives de recherche doivent être dégagées, telles que d'expérimenter ces interventions avec des populations plus à risques ou pathologiques afin de maximiser ces hypothèses et nos résultats

Effect of Resistance Training on Hematological Blood Markers in Older Men and Women: A Pilot Study

The aim of this study was to examine the effects of resistance training on hematological blood markers in older individuals. Twenty-nine men and women participated to this study. Subjects were randomized in 2 groups: (1) control (n = 13) and (2) resistance training (n = 16). At baseline and after the intervention, subjects were submitted to a blood sample to determine their hematological profile (red blood cells, hemoglobin, hematocrit, platelets, leukocytes, neutrophils, lymphocytes, monocytes, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration, red cell distribution width). At baseline, no difference was observed between groups. Moreover, we found no significant difference after the intervention on any of these markers. A 6-month resistance program in healthy older individuals seems to have no beneficial nor deleterious effects on hematological blood parameters. However, resistance training was well tolerated and should be recommended for other health purposes. Further studies are needed to confirm these results in a large population

Influence of aerobic exercise training on the neural correlates of motor learning in Parkinson's disease individuals

Background: Aerobic exercise training (AET) has been shown to provide general health benefits, and to improve motor behaviours in particular, in individuals with Parkinson's disease (PD). However, the influence of AET on their motor learning capacities, as well as the change in neural substrates mediating this effect remains to be explored. Objective: In the current study, we employed functional Magnetic Resonance Imaging (fMRI) to assess the effect of a 3-month AET program on the neural correlates of implicit motor sequence learning (MSL). Methods: 20 healthy controls (HC) and 19 early PD individuals participated in a supervised, high-intensity, stationary recumbent bike training program (3 times/week for 12 weeks). Exercise prescription started at 20 min (+ 5 min/week up to 40 min) based on participant's maximal aerobic power. Before and after the AET program, participants' brain was scanned while performing an implicit version of the serial reaction time task. Results: Brain data revealed pre-post MSL-related increases in functional activity in the hippocampus, striatum and cerebellum in PD patients, as well as in the striatum in HC individuals. Importantly, the functional brain changes in PD individuals correlated with changes in aerobic fitness: a positive relationship was found with increased activity in the hippocampus and striatum, while a negative relationship was observed with the cerebellar activity. Conclusion: Our results reveal, for the first time, that exercise training produces functional changes in known motor learning related brain structures that are consistent with improved behavioural performance observed in PD patients. As such, AET can be a valuable non-pharmacological intervention to promote, not only physical fitness in early PD, but also better motor learning capacity useful in day-to-day activities through increased plasticity in motor related structures

A 12-week cycling training regimen improves gait and executive functions concomitantly in people with parkinson’s disease

Background: There is increasing evidence that executive functions and attention are associated with gait and balance, and that this link is especially prominent in older individuals or those who are afflicted by neurodegenerative diseases that affect cognition and/or motor functions. People with Parkinson’s disease (PD) often present gait disturbances, which can be reduced when PD patients engage in different types of physical exercise (PE), such as walking on a treadmill. Similarly, PE has also been found to improve executive functions in this population. Yet, no exercise intervention investigated simultaneously gait and non-motor symptoms (executive functions, motor learning) in PD patients. Objective: To assess the impact of aerobic exercise training (AET) using a stationary bicycle on a set of gait parameters (walking speed, cadence, step length, step width, single and double support time, as well as variability of step length, step width and double support time) and executive functions (cognitive inhibition and flexibility) in sedentary PD patients and healthy controls. Methods: Two groups, 19 PD patients (Hoehn and Yahr ≤2) and 20 healthy adults, matched on age and sedentary level, followed a 3-month stationary bicycle AET regimen. Results: Aerobic capacity, as well as performance of motor learning and on cognitive inhibition, increased significantly in both groups after the training regimen, but only PD patients improved their walking speed and cadence (all p < 0.05; with no change in the step length). Moreover, in PD patients, training-related improvements in aerobic capacity correlated positively with improvements in walking speed (r = 0.461, p < 0.05). Conclusion: AET using stationary bicycle can independently improve gait and cognitive inhibition in sedentary PD patients. Given that increases in walking speed were obtained through increases in cadence, with no change in step length, our findings suggest that gait improvements are specific to the type of motor activity practiced during exercise (i.e., pedaling). In contrast, the improvements seen in cognitive inhibition were, most likely, not specific to the type of training and they could be due to indirect action mechanisms (i.e., improvement of cardiovascular capacity). These results are also relevant for the development of targeted AET interventions to improve functional autonomy in PD patients

A 12-week cycling training regimen improves upper limb functions in people with Parkinson’s disease

Background: It has been proposed that physical exercise can help improve upper limb functions in Parkinson’s disease (PD) patients; yet evidence for this hypothesis is limited. Objective: To assess the effects of aerobic exercise training (AET) on general upper limb functions in sedentary people with PD and healthy adults (HA). Methods: Two groups, 19 PD patients (Hoehn & Yahr ≤ 2) and 20 HA, matched on age and sedentary level, followed a 3-month stationary bicycle AET regimen. We used the kinematic theory framework to characterize and quantify the different motor control commands involved in performing simple upper-limb movements as drawing lines. Repeated measures ANCOVA models were used to assess the effect of AET in each group, as well as the difference between groups following the training regimen. Results: At baseline, PD individuals had a larger antagonist response, a longer elapsed time between the visual stimulus and the end of the movement, and a longer time of displacement of the stylus than the HA. Following the 12-week AET, PD participants showed significant decreases of the agonist and antagonist commands, as well as the antagonist response spread. A significant group ∗ session interaction effect was observed for the agonist command and the response spread of the antagonist command, suggesting a significant change for these two parameters only in PD patients following the AET. Among the differences observed at baseline, only the difference for the time of movement remained after AET. Conclusion: A 3-month AET has a significant positive impact on the capacity to draw lines in a more efficiency way, in PD patients, indicating an improvement in the upper limb motor function

Effects of Oral Cannabinoids on Systemic Inflammation and Viral Reservoir Markers in People with HIV on Antiretroviral Therapy: Results of the CTN PT028 Pilot Clinical Trial

Chronic HIV infection is characterized by persistent inflammation despite antiretroviral therapy (ART). Cannabinoids may help reduce systemic inflammation in people with HIV (PWH). To assess the effects of oral cannabinoids during HIV, ten PWH on ART were randomized (n = 5/group) to increasing doses of oral Δ9-tetrahydrocannabinol (THC): cannabidiol (CBD) combination (2.5:2.5–15:15 mg/day) capsules or CBD-only (200–800 mg/day) capsules for 12 weeks. Blood specimens were collected prospectively 7–21 days prior to treatment initiation and at weeks 0 to 14. Plasma cytokine levels were determined via Luminex and ELISA. Immune cell subsets were characterized by flow cytometry. HIV DNA/RNA were measured in circulating CD4 T-cells and sperm by ultra-sensitive qPCR. Results from both arms were combined for statistical analysis. Plasma levels of IFN-γ, IL-1β, sTNFRII, and REG-3α were significantly reduced at the end of treatment (p ˂ 0.05). A significant decrease in frequencies of PD1+ memory CD4 T-cells, CD73+ regulatory CD4 T-cells, and M-DC8+ intermediate monocytes was also observed (p ˂ 0.05), along with a transient decrease in CD28–CD57+ senescent CD4 and CD8 T-cells. Ki-67+ CD4 T-cells, CCR2+ non-classical monocytes, and myeloid dendritic cells increased over time (p ˂ 0.05). There were no significant changes in other inflammatory markers or HIV DNA/RNA levels. These findings can guide future large clinical trials investigating cannabinoid anti-inflammatory properties.Medicine, Faculty ofNon UBCPopulation and Public Health (SPPH), School ofReviewedFacultyResearche

Safety and Tolerability of Oral Cannabinoids in People Living with HIV on Long-Term ART: A Randomized, Open-Label, Interventional Pilot Clinical Trial (CTNPT 028)

Background: With anti-inflammatory properties, cannabinoids may be a potential strategy to reduce immune activation in people living with HIV (PLWH) but more information on their safety and tolerability is needed. Methods: We conducted an open-label interventional pilot study at the McGill University Health Centre in Montreal, Canada. PLWH were randomized to oral &Delta;9-tetrahydrocannabinol (THC): cannabidiol (CBD) combination (THC 2.5 mg/CBD 2.5 mg) or CBD-only capsules (CBD 200 mg). Individuals titrated doses as tolerated to a maximum daily dose THC 15 mg/CBD 15 mg or 800 mg CBD, respectively, for 12 weeks. The primary outcome was the percentage of participants without any significant toxicity based on the WHO toxicity scale (Grades 0&ndash;2 scores). Results: Out of ten individuals, eight completed the study. Two from the CBD-only arm were withdrawn for safety concerns: phlebotomy aggravating pre-existing anemia and severe hepatitis on 800 mg CBD with newly discovered pancreatic adenocarcinoma, respectively. Seven did not have any significant toxicity. Cannabinoids did not alter hematology/biochemistry profiles. CD4 count, CD4/CD8 ratio, and HIV suppression remained stable. Most adverse effects were mild-moderate. Conclusions: In PLWH, cannabinoids seem generally safe and well-tolerated, though larger studies are needed. Screening for occult liver pathology should be performed and hepatic enzymes monitored, especially with high CBD doses