Skeletal muscle stem cells, known as satellite cells (SC), are essential for skeletal muscle regeneration/repair and have been linked to muscle hypertrophy in humans. There is a consensus within the literature that SC activate and proliferate in response to external stimuli, such as mechanical damage or exercise. However, the effect of nutritional supplementation in conjunction with exercise on SC function is not fully understood. This may, in part, be due to varying responses of individuals to specific nutritional ingredients. Therefore, this study examined the efficacy of a multicomponent supplement containing whey protein isolate, leucine, creatine monohydrate, calcium citrate, and vitamin D, all of which have independently been shown to confer beneficial effects to skeletal muscle mass or function. Accordingly, when considering individual variability, a multicomponent nutritional strategy, when combined with resistance exercise, may be more likely to produce an augmented response compared to isolated supplements. Healthy, young males and females (18-26 y; ± 0.55) were randomly assigned to a multi-ingredient supplement (MIS)(n=13, 7M) or collagen peptide (CP)(n = 13, 6M) group. Participants performed a whole-body linear resistance-training program 4 times a week for 10-weeks. Skeletal muscle biopsies were obtained from the vastus lateralis pre and post 10 weeks of resistance training. Additionally, biopsies were obtained following an acute bout of damaging eccentric exercise prior to and following the 10 weeks of training. Thus, this design provided a resting and an acute damage response (48-hours post damage) before and after 10-weeks of resistance exercise and supplementation. Training resulted in an 83% and 40% increase in the basal SC population for mixed fibres in the MIS and CP group (P < 0.05), respectively, with no group differences. No effect of time or group was found for acute SC proliferation. However, when collapsing groups, a 635% increase was observed in the relative delta SC activation following 10 weeks (P < 0.05). Also, similar increases were observed in both groups for myonuclear accretion and myonuclear domain (P < 0.05). The MIS group had a 16% larger increase in type II CSA compared to the CP group (P < 0.05). Irrespective of supplementation, our findings suggest 10-weeks of resistance exercise is capable of increasing the basal SC population, SC activation, myonuclear accretion, and myonuclear domain. Furthermore, consuming a MIS lead to superior increases in type II CSA, compared to the CP group. / Thesis / Master of Science (MSc) / Skeletal muscle stem cells, known as satellite cells (SC), are essential for skeletal muscle regeneration/repair and have been linked to muscle hypertrophy in humans. SC activate and proliferate in response to external stimuli, such as mechanical damage or exercise. However, the effect of nutritional supplementation in conjunction with exercise on SC biology is not fully understood. This may, in part, be due to varying responses by individuals to specific nutritional ingredients. In this regard, multi-ingredient supplementation (MIS) has been implemented with the intention of eliciting a maximal adaptive response across all participants. Therefore, this study examined the efficacy of a multicomponent supplement containing whey protein isolate, leucine, creatine monohydrate, calcium citrate, and vitamin D, all of which have independently been shown to confer beneficial effects for skeletal muscle mass or function. Our findings suggest 10-weeks of resistance exercise is capable of increasing the basal SC population, SC activation, myonuclear accretion, and myonuclear domain. Nutritional Supplementation had no further effect. Importantly, however, consuming a MIS lead to greater increases in type II CSA, when compared to a control supplement.
| Identifer | oai:union.ndltd.org:mcmaster.ca/oai:macsphere.mcmaster.ca:11375/25294 |
| Date | January 2020 |
| Creators | Fortino, Stephen |
| Contributors | Parise, Gianni, Kinesiology |
| Source Sets | McMaster University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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