16 research outputs found
PL-001 Home-Based High-Intensity Interval Training Improves Muscle Capillarisation and eNOS/NAD(P)Hoxidase Protein Ratio in Obese Individuals with Elevated Cardiovascular Disease Risk
Objective Obesity and inactivity lead to structural and functional muscle microvascular impairments associated with development of chronic disease. This study is the first to investigate the effect of a novel home-based high-intensity interval training (HIT) (Home-HT) intervention in obese individuals with elevated cardiovascular disease (CVD) risk on capillarisation and muscle microvascular eNOS/NAD(P)Hoxidase ratio. Comparisons were made with home-based moderate-intensity continuous training (Home-MICT) and supervised laboratory-based low-volume HIT (Lab-HIT) as control groups.
Methods Thirty-two sedentary obese adults (age 36±2 years; BMI 34.3±0.8 kg∙m-2; O2peak24.6±1.0 ml∙kg-1∙min-1) were allocated to 12 weeks of Home-HIT (n=9), Home-MICT (n=13) or Lab-HIT (n=10). Muscle biopsies were taken pre- and post-training to assess specifically in the endothelial layer of muscle arterioles and capillaries the protein content of eNOS, serine1177phosphorylated eNOS, NOX2 and p47phox, and various capillarisation measures using quantitative immunofluorescence microscopy.
Results All interventions induced comparable increases in total eNOS content in terminal arterioles and capillaries (P<0.001). There was no change in ser1177phosphorylated eNOS (arterioles P=0.802; capillaries P=0.311), but eNOS ser1177/eNOS ratio significantly decreased following training in arterioles and capillaries (P<0.001). Training decreased NOX2 content (arterioles P<0.001; capillaries P<0.001), but there was no change in p47phoxcontent (arterioles P=0.101; capillaries P=0.345). All measures of capillarisation increased (P<0.05). These adaptations occurred alongside increased O2peak(P<0.001) and whole-body insulin sensitivity (P=0.033). There were no significant differences between training programmes.
Conclusions The training effects of Home-HIT on skeletal muscle microvascular adaptations are comparable to those of traditional training methods, with the advantage that Home-HIT reduces barriers to exercise in obese individuals with elevated CVD risk
PL-017 High-fat overfeeding increases intramuscular triglyceride content and perilipin protein expression in human skeletal muscle
Objective High-fat high-calorie diets can induce whole body insulin resistance (IR) whilst increasing stores of intramuscular triglyceride (IMTG) contained within lipid droplets (LD). Perilipin (PLIN) proteins assist in IMTG storage. Synaptosomal-associated protein (SNAP23) may support LD growth and also direct IMTG-derived fatty acids (FA) to mitochondria for β-oxidation. The objectives of this study were: 1) to test the hypothesis that 7 days of high-fat overfeeding increases IMTG content to prevent lipid induced muscle IR and 2) identify changes in PLINs, SNAP23 and mitochondria content and colocalisation of PLINs with LD, and SNAP23 with LD and mitochondria.
Methods Muscle biopsies were obtained from thevastus lateralisof thirteen healthy individuals (age: 23±1years, BMI: 24.4±0.7kg.m-2) before (0min) and during (30min) an oral glucose tolerance test (OGTT), pre and post 7-days consuming a high-fat (65% energy) high-calorie (+50% kcal) diet. IMTG, PLIN2, PLIN3, PLIN5, SNAP23 and mitochondria content were measured using (semi)-quantitative confocal immunofluorescence microscopy. PLIN2, PLIN3 and PLIN5 colocalisation to LD was measured using object-based colocalisation analyses. Pearson’s correlation coefficient quantified colocalisation between SNAP23 and plasma membrane (PM), mitochondria and LD. Phosphorylation of intermediates of the muscle insulin-signalling cascade (Akt and AS160) were measured at 0 and 30 min of the OGTT before and after the dietary intervention.
Results Following overfeeding phosphorylation of Akt and AS160 in muscle was not impaired during the OGTT, however Matsuda index of whole-body insulin sensitivity decreased (-23%; P < 0.01). IMTG content increased in type I fibres (+100%; P < 0.001) due to both an increase in LD number (+43%; P < 0.001) and size (+44%; P< 0.001). Of the PLINs investigated, only PLIN3 content increased (+50%;P < 0.01) exclusively in type I fibres. PLIN2-associated LD increased (+80%; P < 0.01) in type I fibres only, whereas PLIN3 and PLIN5-associated LD were unaltered. SNAP23 and mitochondria content did not change, nor did the colocalisation of SNAP23 with the PM, mitochondria or LD.
Conclusions Our data confirm the hypothesis that following high-fat overfeeding IMTG stores increased whilst activation of key muscle insulin signalling components were maintained. The increase in IMTG stores is likely supported by the concurrent increase in total PLIN3 content and a redistribution of existing stores of PLIN2 to the expanded LD pool in type I fibres. To confirm if increased IMTG storage protects muscle from IR future research should determine whether meal-derived FAs are directed to IMTG rather than ceramides and diacylglycerol
A Multidisciplinary Evaluation of a Virtually Supervised Home-Based High-Intensity Interval Training Intervention in People With Type 1 Diabetes.
OBJECTIVE: Adopt a multidisciplinary approach to evaluate a virtually supervised home-based high-intensity interval training (Home-HIT) intervention in people with type 1 diabetes. RESEARCH DESIGN AND METHODS: Eleven individuals with type 1 diabetes (seven women; age 30 ± 3 years; VO2peak 2.5 ± 0.2 L/min; duration of diabetes 10 ± 2 years) completed 6 weeks of Home-HIT. A heart rate monitor and mobile phone application were used to provide feedback to the participants and research team on exercise intensity (compliance) and adherence. RESULTS: Training adherence was 95 ± 2%, and compliance was 99 ± 1%. Home-HIT increased VO2peak by 7% (P = 0.017) and decreased insulin dose by 13% (P = 0.012). Blood glucose concentration did not change from baseline to immediately or 1 h post Home-HIT. Qualitative perceptions of Home-HIT and the virtual-monitoring system were positive, supporting that the intervention successfully removed exercise barriers in people with type 1 diabetes. CONCLUSIONS: Virtually monitored Home-HIT resulted in high adherence alongside increased VO2peak and decreased insulin dose
Young, healthy males and females present cardiometabolic protection against the detrimental effects of a 7-day high-fat high-calorie diet
Purpose: High-fat, high-calorie (HFHC) diets have been used as a model to investigate lipid-induced insulin resistance. Short-term HFHC diets reduce insulin sensitivity in young healthy males, but to date, no study has directly compared males and females to elucidate sex-specific differences in the effects of a HFHC diet on functional metabolic and cardiovascular outcomes.
Methods: Eleven males (24 ± 4 years; BMI 23 ± 2 kg.m−2; V̇O2 peak 62.3 ± 8.7 ml.min−1.kg−1FFM) were matched to 10 females (25 ± 4 years; BMI 23 ± 2 kg.m−2; V̇O2 peak 58.2 ± 8.2 ml.min−1.kg−1FFM). Insulin sensitivity, measured via oral glucose tolerance test, metabolic flexibility, arterial stiffness, body composition and blood lipids and liver enzymes were measured before and after 7 days of a high-fat (65% energy) high-calorie (+ 50% kcal) diet.
Results: The HFHC diet did not change measures of insulin sensitivity, metabolic flexibility or arterial stiffness in either sex. There was a trend towards increased total body fat mass (kg) after the HFHC diet (+ 1.8% and + 2.3% for males and females, respectively; P = 0.056). In contrast to females, males had a significant increase in trunk to leg fat mass ratio (+ 5.1%; P = 0.005).
Conclusion: Lean, healthy young males and females appear to be protected from the negative cardio-metabolic effects of a 7-day HFHC diet. Future research should use a prolonged positive energy balance achieved via increased energy intake and reduced energy expenditure to exacerbate negative metabolic and cardiovascular functional outcomes to determine whether sex-specific differences exist under more metabolically challenging conditions
Technical capacities of digitisation centres within ICEDIG participating institutions
DiSSCo, the Distributed System of Scientific Collections, is seeking to centralise certain infrastructure and activities relating to the digitisation of natural science collections. Deciding what activities to distribute, what to centralise, and what geographic level of aggregation (e.g. regional, national or pan European) is most appropriate for each task, was one of the challenges set out within the EC-funded ICEDIG project. In this paper we present the results of a survey of several European collections to establish current digitisation capacity, strengths and skills associated with existing digitisation infrastructure. Our results indicate that most of the institutions surveyed are engaged in large-scale digitisation of collections and that this is usually being undertaken by dedicated teams of digitisers within each institution. Some cross institutional collaboration is happening, but this is still the exception for a variety of funder and practical reasons. These results inform future work that establishes a set of principles to determine how digitisation infrastructure might be most efficiently organised across European organisations in order to maximise progress on the digitisation of the estimated 1.5 billion specimens held within European natural science collections
People with obesity exhibit losses in muscle proteostasis that are partly improved by exercise training.
This pilot experiment examines if a loss in muscle proteostasis occurs in people with obesity and whether endurance exercise positively influences either the abundance profile or turnover rate of proteins in this population. Men with (n = 3) or without (n = 4) obesity were recruited and underwent a 14-d measurement protocol of daily deuterium oxide (D2 O) consumption and serial biopsies of vastus lateralis muscle. Men with obesity then completed 10-weeks of high-intensity interval training (HIIT), encompassing 3 sessions per week of cycle ergometer exercise with 1 min intervals at 100% maximum aerobic power interspersed by 1 min recovery periods. The number of intervals per session progressed from 4 to 8, and during weeks 8-10 the 14-d measurement protocol was repeated. Proteomic analysis detected 352 differences (p < 0.05, false discovery rate < 5%) in protein abundance and 19 (p < 0.05) differences in protein turnover, including components of the ubiquitin-proteasome system. HIIT altered the abundance of 53 proteins and increased the turnover rate of 22 proteins (p < 0.05) and tended to benefit proteostasis by increasing muscle protein turnover rates. Obesity and insulin resistance are associated with compromised muscle proteostasis, which may be partially restored by endurance exercise
The Comparative Methylome and Transcriptome After Change of Direction Compared to Straight Line Running Exercise in Human Skeletal Muscle
The methylome and transcriptome signatures following exercise that are physiologically and metabolically relevant to sporting contexts such as team sports or health prescription scenarios (e.g., high intensity interval training/HIIT) has not been investigated. To explore this, we performed two different sport/exercise relevant high-intensity running protocols in five male sport team members using a repeated measures design of: (1) change of direction (COD) versus; (2) straight line (ST) running exercise with a wash-out period of at least 2 weeks between trials. Skeletal muscle biopsies collected from the vastus lateralis 30 min and 24 h post exercise, were assayed using 850K methylation arrays and a comparative analysis with recent (subject-unmatched) sprint and acute aerobic exercise meta-analysis transcriptomes was performed. Despite COD and ST exercise being matched for classically defined intensity measures (speed × distance and number of accelerations/decelerations), COD exercise elicited greater movement (GPS-Playerload), physiological (HR), metabolic (lactate) as well as central and peripheral (differential RPE) exertion measures compared with ST exercise, suggesting COD exercise evoked a higher exercise intensity. The exercise response alone across both conditions evoked extensive alterations in the methylome 30 min and 24 h post exercise, particularly in MAPK, AMPK and axon guidance pathways. COD evoked a considerably greater hypomethylated signature across the genome compared with ST exercise, particularly at 30 min post exercise, enriched in: Protein binding, MAPK, AMPK, insulin, and axon guidance pathways. Comparative methylome analysis with sprint running transcriptomes identified considerable overlap, with 49% of genes that were altered at the expression level also differentially methylated after COD exercise. After differential methylated region analysis, we observed that VEGFA and its downstream nuclear transcription factor,NR4A1had enriched hypomethylation within their promoter regions.VEGFAandNR4A1were also significantly upregulated in the sprint transcriptome and meta-analysis of exercise transcriptomes. We also confirmed increased gene expression ofVEGFA, and considerably larger increases in the expression of canonical metabolic genesPPARGC1A (that encodes PGC1-α) andNR4A3in COD vs. ST exercise. Overall, we demonstrate that increased physiological/metabolic load via COD exercise in human skeletal muscle evokes considerable epigenetic modifications that are associated with changes in expression of genes responsible for adaptation to exercise
The comparative methylome and transcriptome after change of direction compared to straight line running exercise in human skeletal muscle
The methylome and transcriptome signatures following exercise that are physiologically and metabolically relevant to sporting contexts such as team sports or health prescription scenarios (e.g., high intensity interval training/HIIT) has not been investigated. To explore this, we performed two different sport/exercise relevant high-intensity running protocols in five male sport team members using a repeated measures design of: (1) change of direction (COD) versus; (2) straight line (ST) running exercise with a wash-out period of at least 2 weeks between trials. Skeletal muscle biopsies collected from the vastus lateralis 30 min and 24 h post exercise, were assayed using 850K methylation arrays and a comparative analysis with recent (subject-unmatched) sprint and acute aerobic exercise meta-analysis transcriptomes was performed. Despite COD and ST exercise being matched for classically defined intensity measures (speed   distance and number of accelerations/decelerations), COD exercise elicited greater movement (GPS-Playerload), physiological (HR), metabolic (lactate) as well as central and peripheral (differential RPE) exertion measures compared with ST exercise, suggesting COD exercise evoked a higher exercise intensity. The exercise response alone across both conditions evoked extensive alterations in the methylome 30 min and 24 h post exercise, particularly in MAPK, AMPK and axon guidance pathways. COD evoked a considerably greater hypomethylated signature across the genome compared with ST exercise, particularly at 30 min post exercise, enriched in: Protein binding, MAPK, AMPK, insulin, and axon guidance pathways. Comparative methylome analysis with sprint running transcriptomes identified considerable overlap, with 49% of genes that were altered at the expression level also differentially methylated after COD exercise. After differential methylated region analysis, we observed that VEGFA and its downstream nuclear transcription factor, NR4A1 had enriched hypomethylation within their promoter regions. VEGFA and NR4A1 were also significantly upregulated in the sprint transcriptome and meta-analysis of exercise transcriptomes.We also confirmed increased gene expression of VEGFA, and considerably larger increases in the expression of canonical metabolic genes PPARGC1A (that encodes PGC1-a) and NR4A3 in COD vs. ST exercise. Overall, we demonstrate that increased physiological/metabolic load via COD exercise in human skeletal muscle evokes considerable epigenetic modifications that are associated with changes in expression of genes responsible for adaptation to exercise