ECSS Paris 2023: CP-PN06
INTRODUCTION: There exists a correlation between a healthy physiological state and the diversity of gut microbiome. Menopause-induced deteriorations in whole body metabolism, including insulin resistance and obesity, negatively contribute to microbial diversity. Firmicutes including UCG009 is associated with enhanced energy storage leading to metabolic dysfunction and obesity. Acetic acid supplement or exercise intervention has been somewhat documented for its beneficial effects on gut microbial composition. However, the combined influence of acetic acid supplement and exercise intervention on gut microbiome remains unknown. The purpose of the study was to investigate 1) whether menopause negatively influences gut microbial diversity including firmicutes abundance; and 2) whether the combined treatment of acetic acid and exercise rescues this microbial dysbiosis , and which specific bacteria is related to this rescuing effect . METHODS: This 15-week study used female C57BL/6J wild type mice (n=40, 8 weeks old), which were randomly assigned to Sham (SHM), ovariectomy (OVX), ovariectomy with exercise (OVXE), ovariectomy with acetic acid (OVXA), and ovariectomy with exercise and acetic acid (OVXAE) groups. Gut microbial diversity including abundance profiling in phylum level was accessed using Next Generation Sequencing (NGS). Beta diversity using Bray-Curtis Index and Unweighted UniFrac Index measured diversity differences between groups. Phylogenetic cladogram was used to analyze the group difference in specific bacteria. RESULTS: In the abundance of firmicutes, OVX exhibited a tendency for an increase compared to SHM. However, OVXA showed no difference compared to SHM (SHM: 50.6%; OVX: 57.2%; OVXE: 52.0%; OVXA: 50.6%; OVXAE: 56.5). In microbial diversity, while there was no difference between SHM and OVX, acetic acid supplement groups (OVXA and OVXAE) showed greater diversity compared to SHM and OVX (p < 0.05). In phylogenetic cladogram analysis, compared to OVX, OVXA and OVXAE had lower level of UCG009 and Akkermansia (p < 0.05). CONCLUSION: Ovariectomy, a model of menopause, tended to increase the relative proportion of Firmicutes. Acetic acid supplement partially maintained the Firmicutes proportion in ovariectomized mice. The noteworthy finding of the study is that, independent of exercise intervention, acetic acid supplement showed a significant, beneficial effect on microbial diversity in ovariectomized mice. Future research should explore the potential role of UCG009 in protecting against the menopause-related metabolic dysfunction.
Read CV YUAN TANECSS Paris 2023: CP-PN06
INTRODUCTION: Estrogen, a primary female sex hormone, plays a key role in the adaptation of muscle after exercise (1,2). Possible mechanisms for the estrogen-muscle interaction include regulating satellite cells, which are important in repair and remodelling of muscle, and inhibiting muscular inflammation after exercise (1,3). Estrogen exerts its effects through acting on estrogen receptors located on skeletal muscle (4). How synthetic female sex hormones, such as the ones found in oral contraceptive pills (OCPs), impact skeletal muscle after exercise, including fibre size, lean body mass, and the satellite cell response remains unknown. The purpose of this study was to determine the effect that OCP use has on the response to the early phases of a resistance training program. METHODS: Twenty-eight healthy, young females (21.2 ± 1.1 years, 64.5 ± 4.0 kg) were recruited and categorized as either OCP users (n=14) or naturally cycling (n=14). Each participant underwent a four-week resistance training protocol. Muscle characteristics (fiber cross sectional area, fiber type), strength, lean body mass via DEXA scanning, as well as satellite cell content were evaluated using immunofluorescent staining. RESULTS: There were no significant differences between OCP users and naturally cycling individuals with respect to fiber cross sectional area, fiber type, strength gains, and satellite cell content after 4 weeks of resistance training (p>0.05). OCP users gained significantly more lean body mass as measured by DEXA compared to naturally cycling individuals (p<0.05), but both groups improved lean leg mass, equally, with training (p=0.01). CONCLUSION: OCP use does not differentially impact fiber cross sectional area, fiber type, strength, and satellite cell content compared to naturally cycling individuals after 4 weeks of resistance training. The results obtained from this study further simplify inclusion criteria for future muscle physiology studies aiming to recruit female participants. References: 1. Pellegrino, A., Tiidus, P. M., & Vandenboom, R. (2022). Mechanisms of estrogen influence on skeletal muscle: mass, regeneration, and mitochondrial function. Sports medicine, 52(12), 2853-2869. 2. Collins, B. C., Arpke, R. W., Larson, A. A., Baumann, C. W., Xie, N., Cabelka, C. A., ... & Lowe, D. A. (2019). Estrogen regulates the satellite cell compartment in females. Cell reports, 28(2), 368-381. 3. Ikeda, K., Horie-Inoue, K., & Inoue, S. (2019). Functions of estrogen and estrogen receptor signaling on skeletal muscle. The Journal of steroid biochemistry and molecular biology, 191, 105375. 4. Velders, M., & Diel, P. (2013). How sex hormones promote skeletal muscle regeneration. Sports medicine, 43(11), 1089-1100.
Read CV Rebecca LadouceurECSS Paris 2023: CP-PN06
INTRODUCTION: The combination of oral L-arginine and L-citrulline immediately and synergistically increases plasma arginine and nitrite/nitrate (NOx) concentrations more than either citrulline or arginine alone (1,2). Nitric oxide (NO) is the most important endothelium-derived relaxing factor, which plays a pivotal role in modulating smooth muscle tone (3). During exercise, increasing NO production facilitate blood flow in muscle tissues, muscle energy metabolism, and mitochondrial respiration, therefore previous human study has reported that oral arginine-citrulline supplement improved exercise performance due to increase NO bioavailability (1). However, there is little data concerning the effect of arginine-citrulline supplement on skin-gas NO concentration during exercise. The present study examined to confirm the effect of arginine-citrulline supplement on blood flow of active muscles and skin-gas NO concentrations following maximal running exercise. METHODS: A double-blind randomized placebo-controlled 2-way crossover study was employed. Ten healthy male students (23.0 ± 0.5 years; mean ± SD) consumed arginine-citrulline supplement (VELOX Charge: Kyowa Kirin Co., Ltd., Japan) or placebo orally 1 h before incremental maximal running exercise exhausting within 30 min. The skin-gas samples were obtained from the dominant hand by covering with a polyethylene bag in which pure nitrogen gas (250mL) was introduced for 100 sec and collected in a sampling bag at rest and 0, 5, 10, 15, 30 min recovery of the exercise. The skin-gas NO concentration was measured by a chemiluminescence analyzer (Pico-Device Co., Ltd., Japan). Blood flow measured using a laser tissue blood flow meter from non-dominant hand skin surface (Omegaflo, Omega Wave, Japan). RESULTS: The arginine-citrulline supplement significantly (p<0.05) increased running time and distance compared to the placebo. Maximal exercise in this study significantly increased skin-gas NO concentration (p<0.05) and blood flow (p<0.001) after the exercise compared to the resting values. Significant higher levels were observed in skin-gas NO concentration (p<0.001) and blood flow (p<0.001) in the supplemental condition compared to the placebo. Moreover, there were significant relationships between skin-gas NO concentration and blood flow both in supplemental (r = 0.5676, p<0.001) and placebo (r = 0.6050, p<0.001) conditions. CONCLUSION: Significantly higher levels of skin-gas NO concentration has indicated that the arginine-citrulline supplement increased NO production and NO bioavailability in the whole body during the maximal exercise. As a result, blood flow, energy metabolism, and mitochondrial respiration in active quadriceps muscle during the maximal running exercise facilitated by the arginine-citrulline supplement, consequently improved exercise performance (1). 1 Suzuki I et al. (2019) Eur J Appl Physiol., 119(5):1075-1084. 2 Morita M et al. (2014) Biochem Biophys Res Commun., 7;454(1):53-7. 3 Moncada S and Higgs E (2006) Br J Pharmacol
Read CV Atsushi OCHIAIECSS Paris 2023: CP-PN06