Biology subjects

Belanger, M.

Publications and source records attributed to Belanger, M..

7 recordsLinked to original sources

bioRxiv2026

Daily physical activity behavior: a compensatory factor to physical adaptations variability following a 12-week power training in older men

Physical activity (PA) is effective to counteract age-related declines. However, inter-individual variability in training adaptations may limit prediction of individual responses and intervention optimization. Daily PA behavior may contribute to this variability. The objective was to examine daily PA behavior through a 12-week supervised power training (PT) and its associations with clinical adaptations in 36 older men. Time of PA, step count, total (TEE) and active (AEE) energy expenditure, metabolic equivalents of task (METs), and sedentary time were assessed using a 3D accelerometer for three days surrounding PT sessions (Day-PT-1, Day-PT and Day-PT+1) at pre-(T0) and mid-intervention (6-week; T6). Physical performance, body composition and muscle function were assessed pre-(T0) and post-(T12) intervention. PA behavior outcomes did not change between T0 and T6, except for METs which decreased by 0.2 METS (T0:1.44{+/-}0.34 vs. T6:1.25{+/-} 0.18; p=0.003 [13%]). At T6, day-to-day fluctuations were observed for PA behavior on Day-PT-1 and Day-PT+1 compared with Day-PT (all ps<0.05). Following the intervention, body composition and muscle characteristics improved significantly. Between T6-Day-PT-1 and T6-Day-PT, greater increases in time of PA were associated with lower Fast Timed Up and Go speed adaptation (p=0.02), and greater reductions in step count were associated with greater reductions in muscle power (p=0.02). Finally, increases in step count and time of PA were associated with greater upper limb strength (p=0.04) and muscle pennation angle (p=0.02). PA behavior appears modulated during a 12-week PT intervention in healthy older men. Thus, PA behavior surrounding training sessions could be an important compensatory factor contributing to adaptations variability.

physiology↗

bioRxiv2026

Serum C-terminal agrin fragment as a biomarker of age-related neuromuscular decline in men: influence of physical activity

Aging is accompanied by progressive neuromuscular junction (NMJ) degeneration. The C-terminal agrin fragment (CAF), a circulating product of agrin cleavage, has been proposed as a minimally invasive biomarker of NMJ degradation, but its relationships with neuromuscular and functional characteristics, and the influence of physical activity, remain underexplored. We studied 136 community-dwelling men aged 20-92 years (active, n=87; inactive, n=49). Serum CAF was measured by ELISA. The proportion of NCAM-positive fibers, a marker of myofiber denervation, was assessed in vastus lateralis biopsies (n=127). Neuromuscular outcomes included maximal voluntary isometric contraction (MVIC), lower-limb power, electromechanical delay (EMD), nerve conduction velocities, H/M ratio, central activation ratio, co-activation, and twitch characteristics. Functional capacity was assessed using the 6-minute walk test, alternating step test, Timed Up and Go, sit-to-stand tests, and fast gait speed. Serum CAF increased with age and was positively associated with NCAM-positive fiber proportion. Higher CAF was associated with lower MVIC, lower-limb power and poorer performance on all functional tests. CAF was associated with longer EMD in the overall cohort and in inactive men only, and with a lower H/M ratio in inactive men. No associations were found with nerve conduction velocities, central activation ratio, co-activation, or twitch amplitude. Active men had lower CAF levels than inactive men, particularly after age 70. Serum CAF is associated with age-related declines in neuromuscular and functional capacity and with NCAM-positive fiber prevalence, supporting its utility as an accessible biomarker of NMJ remodeling. Physical activity was associated with a more favorable CAF profile in older men.

physiology↗

bioRxiv2026

Multi-point convective delivery overcomes mass transport barriers for myocardial therapeutics

Angiogenesis-promoting macromolecules reduce adverse remodeling and preserve cardiac function in rodents following myocardial infarctions, yet repeatedly fail to translate across length scales in humans. Through mass transport studies in human and swine myocardium, we found that dense, anisotropic myocardial fibers limit therapeutic diffusion and convection to millimeter scales for existing approaches including bolus intramyocardial injections, shear-thinning hydrogels, and epicardial patches. Furthermore, distributions are confined to one dimension along fibers. To increase myocardial drug distribution to centimeter length scales in vivo in swine, we engineered a three-dimensional multi-injection drug delivery array. Our device performs up to 40 simultaneous 120 {micro}L injections of functional macromolecules, hydrogels, or mRNA lipid nanoparticles. Injections are precisely placed in relation to fiber alignment, achieving near-complete coverage of the left ventricular myocardium.

bioengineering↗

bioRxiv2025

Live fast and die young: walleye populations adapt their life cycle to degraded lakes of the Canadian clay belt.

Despite its widespread distribution in North America, many populations of walleye (Sander vitreus) declined to the point where restoration measures, including restocking, are necessary. In this study, we compared population structure and dietary composition of walleye populations in two degraded lakes and two non-degraded lakes in the Abitibi-Temiscamingue region of Quebec, Canada. Food resources were assessed for walleye larvae, young-of-the-year, juveniles, and adults. Growth and relative abundance were also quantified for young-of-the-year, juvenile, and adult walleye. Young-of-the-year were more abundant and grew faster in degraded lakes compared to non-degraded controls, benefiting from high populations of spring zooplankton, which are a critical larval resource. The simplified food webs in degraded lakes lacked pollution-sensitive macroinvertebrates, which resulted in walleye diets being even more dominated by fish. Although juveniles and adults were equally or more abundant in degraded lakes compared to control lakes, premature adult mortality compromised population stability. We recommend focusing on improving adult fish habitat, manage for prey species, and review fishing regulations to enhance the survival of mature walleye and ensure sustainable populations.

ecology↗

bioRxiv2024

Impact of physical activity on physical performance, mitochondrial bioenergetics, ROS production and calcium handling across the human adult lifespan

Aging-related muscle atrophy and weakness contribute to loss of mobility, falls and disability. Mitochondrial dysfunction is widely considered a key contributing mechanism to muscle aging. However, mounting evidence position physical activity as a confounding factor, making unclear whether muscle mitochondria accumulate bona fide defects with aging. To disentangle aging from physical activity-related mitochondrial adaptations, we functionally profiled skeletal muscle mitochondria in 51 inactive and 88 active men aged 20-93. Physical activity status conferred partial protection against age-related decline in physical performance. A trend for reduced muscle mitochondrial respiration with aging was observed in inactive but not in active participants, indicating that aging per se does not alter mitochondrial respiratory capacity. Mitochondrial reactive oxygen species (ROS) production was unaffected by aging and active participants displayed higher ROS production. In contrast, mitochondrial calcium retention capacity decreased with aging regardless of physical activity status and correlated with muscle mass, performance and the stress-responsive metabokine GDF15. Targeting mitochondrial calcium handling may hold promise for treating aging-related muscle impairments.

cell biology↗

bioRxiv2021

Rewiring the Three-Carbon Metabolism Abrogates Multiple MAPK-Induced Cellular Dysfunctions During Metabolic Disorder

Withdrawal noticeThe authors have withdrawn their manuscript. The lipidomic data presented in the manuscript were based on an excel summary sheet provided by VIT, whose group (AP and KM) conducted the analysis using an Orbitrap mass spectrometer. However, after submitting to BioRxiv, the VIT group could not recover the RAW (primary source) files from the lipidomic platform because these files were deleted due to the maintenance protocol used for the Orbitrap mass spectrometer. It was agreed to reconduct the lipidomic analysis. As the Orbitrap mass spectrometer was out of service at that time, the lipidomic analysis was conducted with the help of a QToF mass spectrometer. Important differences were noted for the relative abundance and species of many lipids across the strains compared to the previously reported data hence casting some doubt on their interpretation. Therefore, until further analysis can be carried out the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

cell biology↗

bioRxiv2019

Platinum chemotherapy induces lymphangiogenesis to prime tissues for tumor metastasis

Chemotherapy has been used to inhibit cancer growth for decades, but emerging evidence shows it can affect the tumor stroma unintentionally promoting cancer malignancy. After treatment of primary tumors, remaining drugs drain via lymphatics. Though all drugs interact with the lymphatics, we know little of their impact on them. Here, we show a previously unknown effect of platinums, a widely used class of chemotherapeutics, to directly induce systemic lymphangiogenesis and activation. These changes are dose-dependent, long-lasting, and occur in healthy and cancerous tissue in multiple mouse models of breast cancer. We saw similar effects in human ovarian and breast cancer patients whose treatment regimens included platinums. Carboplatin treatment of healthy mice prior to mammary tumor inoculation increases cancer metastasis as compared to no pre-treatment. These platinum-induced phenomena could be blocked by VEGFR3 inhibition. These findings have implications for cancer patients receiving platinums and may support the inclusion of anti-VEGFR3 therapy into treatment regimens or differential design of treatment regimens to alter these potential effects. SummaryPlatinum chemotherapy induces VEGFR3-dependent lymphangiogenesis, priming tissues for metastasis of breast cancer. Inhibition of VEGFR3 via antibody blockade can reverse these effects.

cancer biology↗