ORCID Profile
0000-0002-0327-5726
Current Organisation
Monash University
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Publisher: Wiley
Date: 19-10-2023
DOI: 10.1113/JP285130
Publisher: Wiley
Date: 02-06-2016
DOI: 10.1113/EP085647
Publisher: Frontiers Media SA
Date: 30-08-2019
Publisher: MDPI AG
Date: 28-06-2020
Abstract: Obesity is recognised as a risk factor for many types of cancers, in particular hepatocellular carcinoma (HCC). A critical factor in the development of HCC from non-alcoholic fatty liver disease (NAFLD) is the presence of non-alcoholic steatohepatitis (NASH). Therapies aimed at NASH to reduce the risk of HCC are sparse and largely unsuccessful. Lifestyle modifications such as diet and regular exercise have poor adherence. Moreover, current pharmacological treatments such as pioglitazone and vitamin E have limited effects on fibrosis, a key risk factor in HCC progression. As NAFLD is becoming more prevalent in developed countries due to rising rates of obesity, a need for directed treatment is imperative. Numerous novel therapies including PPAR agonists, anti-fibrotic therapies and agents targeting inflammation, oxidative stress and the gut-liver axis are currently in development, with the aim of targeting key processes in the progression of NASH and HCC. Here, we critically evaluate literature on the aetiology of NAFLD-related HCC, and explore the potential treatment options for NASH and HCC.
Publisher: Human Kinetics
Date: 03-2019
Abstract: A linear dose-response relationship between resistance-training (RT) volume and hypertrophy/strength has been proposed when ≤10 to 12 weekly sets are implemented. The present study aimed to understand the impact of low to high weekly RT volume on muscular adaptations in trained young men over 6 wk of RT. RT-experienced men (N = 49) were randomly allocated to a low (LOW n = 17), moderate (MOD n = 15), or high (HIGH, n = 17) -volume group, performing 9, 18, or 27 weekly sets of biceps RT, respectively, for 6 wk. RT was performed once (LOW) or twice (MOD and HIGH) weekly. Postexercise protein intake was controlled with both dietary intake and external training volume recorded. Before and after RT, assessments of biceps muscle thickness (MT) via ultrasound, isometric, and 1-repetition-maximum (1RM) strength were performed. Data were analyzed using 1-way analysis of variance (baseline characteristics) and repeated-measures analysis of variance (within- and between-groups pre-to-post change). MT significantly increased in all groups (4.3% [7.9%], 9.5% [11.8%], and 5.4% [6.3%] for LOW, MOD, and HIGH, respectively P < .05), as did 1RM strength (P ≤ .001 for all). Isometric strength increased significantly in HIGH only (8.5% [15.1%], P < .05). There were no significant differences between groups in MT or indices of strength. However, effect-size estimates revealed that the magnitude of response was "moderate to large" for MOD and HIGH when compared with LOW. The findings demonstrate that 9 weekly sets of biceps-focused RT, performed in 1 weekly session, are sufficient to increase MT, whereas 18-27 sets performed over 2 weekly sessions may confer greater strength increases.
Publisher: Frontiers Media SA
Date: 16-03-2020
Publisher: Elsevier BV
Date: 06-2019
DOI: 10.1016/J.CLNU.2018.06.963
Abstract: Age-related muscle loss (sarcopenia) may be driven by a diminished myofibrillar protein synthesis (MyoPS) response to anabolic stimuli (i.e. exercise and nutrition). Oral phosphatidic acid (PA) ingestion has been reported to stimulate resting muscle protein synthesis in rodents, and enhance resistance training-induced muscle remodelling in young humans. This study examined the effects of acute oral PA ingestion on resting and exercise-induced MyoPS rates in older in iduals. Sixteen older males performed a bout of unilateral leg resistance exercise followed by oral ingestion of 750 mg of soy-derived PA or a rice-flour placebo (PL) over 60 min post-exercise. A primed-continuous infusion of l-[ring- Plasma [PA] concentrations were elevated above basal values from 180 to 300 min post-exercise in PA only (P = 0.02). Exercise increased MyoPS rates above basal values between 150 and 300 min post-exercise in PL (P = 0.001), but not PA (P = 0.83). Phosphorylation of p70S6K, rpS6, 4E-BP1 and Akt was elevated above basal levels in the exercised leg over 150-300 min post-exercise for PL only (P = 0.018, 0.007, 0.011 and 0.002, respectively), and were significantly greater than PA (P < 0.01 for all proteins). The effects of oral PA ingestion on proteolytic signaling markers were equivocal. Acute oral phosphatidic acid ingestion appears to interfere with resistance exercise-induced intramuscular anabolic signaling and MyoPS in older males and, therefore, may not be a viable treatment to counteract sarcopenia. Clinicaltials.gov registration no: NCT03446924.
Publisher: The Endocrine Society
Date: 14-07-2017
Publisher: MDPI AG
Date: 25-05-2020
DOI: 10.3390/NU12051533
Abstract: Preserving skeletal muscle mass and functional capacity is essential for healthy ageing. Transient periods of disuse and/or inactivity in combination with sub-optimal dietary intake have been shown to accelerate the age-related loss of muscle mass and strength, predisposing to disability and metabolic disease. Mechanisms underlying disuse and/or inactivity-related muscle deterioration in the older adults, whilst multifaceted, ultimately manifest in an imbalance between rates of muscle protein synthesis and breakdown, resulting in net muscle loss. To date, the most potent intervention to mitigate disuse-induced muscle deterioration is mechanical loading in the form of resistance exercise. However, the feasibility of older in iduals performing resistance exercise during disuse and inactivity has been questioned, particularly as illness and injury may affect adherence and safety, as well as accessibility to appropriate equipment and physical therapists. Therefore, optimising nutritional intake during disuse events, through the introduction of protein-rich whole-foods, isolated proteins and nutrient compounds with purported pro-anabolic and anti-catabolic properties could offset impairments in muscle protein turnover and, ultimately, the degree of muscle atrophy and recovery upon re-ambulation. The current review therefore aims to provide an overview of nutritional countermeasures to disuse atrophy and anabolic resistance in older in iduals.
Publisher: Canadian Science Publishing
Date: 12-2015
Abstract: Skeletal muscle mass plays a vital role in locomotion, whole-body metabolic health, and is a positive predictor of longevity. It is well established the mammalian target of rapamycin (mTOR) is a central regulator of skeletal muscle protein turnover. The pursuit to find novel nutrient compounds or functional food sources that possess the ability to activate mTOR and promote skeletal muscle protein accretion has been on going. Over the last decade, a key role has been proposed for the phospholipid phosphatidic acid (PA) in mTOR activation. Mechanical load-induced (i.e., resistance exercise) intramuscular PA can directly bind to and activate mTOR. In addition, PA provided exogenously in cell culture heightens mTOR activity, albeit indirectly. Thus, endogenously generated PA and exogenous provision of PA appear to act through distinct mechanisms that converge on mTOR and, potentially, may lify muscle protein synthesis. In support of this notion, limited evidence from humans suggests that resistance exercise training combined with oral supplemental PA enhances strength gains and muscle hypertrophy. However, the precise mechanisms underpinning the augmented muscle remodelling response with supplemental PA remain elusive. In this review, we will critically examine available evidence from cell cultures and animal and human experimental models to provide an overview of the mechanisms through which endogenous and exogenous PA may act to promote muscle anabolism, and discuss the potential for PA as a therapeutic tool to maintain or restore skeletal muscle mass in the context of ageing and disease.
Publisher: Wiley
Date: 14-12-2016
DOI: 10.1113/JP273343
Publisher: Springer Science and Business Media LLC
Date: 10-01-2020
DOI: 10.1038/S41467-019-13889-6
Abstract: mTORC1 is an important regulator of muscle mass but how it is modulated by oxygen and nutrients is not completely understood. We show that loss of the prolyl hydroxylase domain isoform 1 oxygen sensor in mice (PHD1 KO ) reduces muscle mass. PHD1 KO muscles show impaired mTORC1 activation in response to leucine whereas mTORC1 activation by growth factors or eccentric contractions was preserved. The ability of PHD1 to promote mTORC1 activity is independent of its hydroxylation activity but is caused by decreased protein content of the leucyl tRNA synthetase (LRS) leucine sensor. Mechanistically, PHD1 interacts with and stabilizes LRS. This interaction is promoted during oxygen and amino acid depletion and protects LRS from degradation. Finally, elderly subjects have lower PHD1 levels and LRS activity in muscle from aged versus young human subjects. In conclusion, PHD1 ensures an optimal mTORC1 response to leucine after episodes of metabolic scarcity.
Publisher: MDPI AG
Date: 28-12-2019
DOI: 10.3390/NU12010090
Abstract: Maintaining adequate daily protein intake is important to maintain muscle mass throughout the lifespan. In this regard, the overnight period has been identified as a window of opportunity to increase protein intake in the elderly. However, it is unknown whether pre-sleep protein intake affects next-morning appetite and, consequently, protein intake. Therefore, the purpose of the current study was to investigate the effects of a pre-sleep protein drink on next-morning appetite, energy intake and metabolism. Twelve older in iduals (eight males, four females age: 71.3 ± 4.2 years) took part in a single-blind randomised cross-over study. After a standardised dinner, participants consumed either a 40-g protein drink, isocaloric maltodextrin drink, or placebo water control before bedtime. Next-morning appetite, energy intake, resting metabolic rate (RMR), respiratory exchange rate (RER), and plasma acylated ghrelin, leptin, glucose, and insulin concentrations were assessed. No between-group differences were observed for appetite and energy intake at breakfast. Furthermore, RMR, RER, and assessed blood markers were not significantly different between any of the treatment groups. Pre-sleep protein intake does not affect next-morning appetite and energy intake and is therefore a viable strategy to increase daily protein intake in an older population.
Publisher: American Physiological Society
Date: 07-2020
DOI: 10.1152/AJPCELL.00072.2020
Abstract: The role of dysregulated intracellular creatine (Cr) metabolism in disuse atrophy is unknown. In this study, skeletal muscle biopsy s les were obtained after 7 days of unilateral leg immobilization (IMMOB) and from the nonimmobilized control limb (CTRL) of 15 healthy men (23.1 ± 3.5 yr). S les were analyzed for fiber type cross-sectional area (CSA) and creatine transporter (CreaT) at the cell membrane periphery (MEM) or intracellular (INT) areas, via immunofluorescence microscopy. Creatine kinase (CK) and AMP-activated protein kinase (AMPK) were determined via immunoblot. Phosphocreatine (PCr), Cr, and ATP were measured via enzymatic analysis. Body composition and maximal isometric knee extensor strength were assessed before and after disuse. Leg strength and fat-free mass were reduced in IMMOB (~32% and 4%, respectively P 0.01 for both). Type II fiber CSA was smaller (~12% P = 0.028) and intramuscular PCr lower (~13% P = 0.015) in IMMOB vs. CTRL. CreaT protein was greater in type I fibers in both limbs ( P 0.01). CreaT was greater in IMMOB vs. CTRL ( P 0.01) and inversely associated with PCr concentration in both limbs ( P 0.05). MEM CreaT was greater than INT CreaT in type I and II fibers of both limbs (~14% for both P 0.01 for both). Type I fiber CreaT tended to be greater in IMMOB vs. CTRL ( P = 0.074). CK was greater and phospho-to-total AMPK Thr172 tended to be greater , in IMMOB vs. CTRL ( P = 0.013 and 0.051, respectively). These findings suggest that modulation of intracellular Cr metabolism is an adaptive response to immobilization in young healthy skeletal muscle.
Publisher: American Association for the Advancement of Science (AAAS)
Date: 15-09-2023
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Benoit Smeuninx.