Cold acclimation with shivering improves metabolic health in adults with overweight or obesity.

Cold acclimation increases insulin sensitivity, and some level of muscle contraction appears to be needed for provoking this effect. Here 15 men and (postmenopausal) women with overweight or obesity, the majority of whom had impaired glucose tolerance, were intermittently exposed to cold to induce 1 h of shivering per day over 10 days. We determined the effect of cold acclimation with shivering on overnight fasted oral glucose tolerance (primary outcome) and on skeletal muscle glucose transporter 4 translocation (secondary outcome).

The effect of altered sleep timing on glycaemic outcomes: Systematic review of human intervention studies.

Aims: Alterations in sleep timing can lead to disturbances in glycaemic control, although the evidence is inconsistent. Therefore, this systematic review summarizes results from human intervention studies of altered sleep timing on glycaemic outcomes.

Materials And Methods: As part of a broader search on the effect of altering timing of sleep, physical activity and dietary intake, Medline and Embase were searched from inception to February 2023, and subsequent reference searches were done.

Plasma triacylglycerol length and saturation level mark healthy aging groups in humans.

Complex lipids, essential components in biological processes, exhibit conserved age-related changes that alter membrane properties and cellular functions and are implicated as biomarkers and contributors to longevity and age-related diseases. While physical activity alleviates age-related comorbidities and physical impairments, comprehensive exploration of the underlying biological mechanisms, particularly at the level of complex lipids, remains limited. However, clinical studies suggest that physical activity may counteract these age-related lipidomic changes, presenting a promising avenue for intervention.

Development of a P magnetic resonance spectroscopy technique to quantify NADH and NAD at 3 T.

NADH and NAD act as electron donors and acceptors and NAD was shown to stimulate mitochondrial biogenesis and metabolic health. We here develop a non-invasive Phosphorous Magnetic Resonance Spectroscopy (P-MRS) method to quantify these metabolites in human skeletal muscle on a clinical 3 T MRI scanner. This new MR-sequence enables NADH and NAD+ quantification by suppressing α-ATP signal, normally overlapping with NADH and NAD.

The novel adrenergic agonist ATR-127 targets skeletal muscle and brown adipose tissue to tackle diabesity and steatohepatitis.

Objective: Simultaneous activation of β2- and β3-adrenoceptors (ARs) improves whole-body metabolism via beneficial effects in skeletal muscle and brown adipose tissue (BAT). Nevertheless, high-efficacy agonists simultaneously targeting these receptors whilst limiting activation of β1-ARs - and thus inducing cardiovascular complications - are currently non-existent. Therefore, we here developed and evaluated the therapeutic potential of a novel β2-and β3-AR, named ATR-127, for the treatment of obesity and its associated metabolic perturbations in preclinical models.

A conserved complex lipid signature marks human muscle aging and responds to short-term exercise.

Studies in preclinical models suggest that complex lipids, such as phospholipids, play a role in the regulation of longevity. However, identification of universally conserved complex lipid changes that occur during aging, and how these respond to interventions, is lacking. Here, to comprehensively map how complex lipids change during aging, we profiled ten tissues in young versus aged mice using a lipidomics platform.

Exercise training modifies skeletal muscle clock gene expression but not 24-hour rhythmicity in substrate metabolism of men with insulin resistance.

Twenty-four hour rhythmicity in whole-body substrate metabolism, skeletal muscle clock gene expression and mitochondrial respiration is compromised upon insulin resistance. With exercise training known to ameliorate insulin resistance, our objective was to test if exercise training can reinforce diurnal variation in whole-body and skeletal muscle metabolism in men with insulin resistance. In a single-arm longitudinal design, 10 overweight and obese men with insulin resistance performed 12 weeks of high-intensity interval training recurrently in the afternoon (between 14.

The impact of prolonged fasting on 24h energy metabolism and its 24h rhythmicity in healthy, lean males: A randomized cross-over trial.

Objective: Human energy expenditure and substrate oxidation are under circadian control and food intake is a time cue for the human biological clock, leading to 24h feeding-fasting cycles in energy and substrate metabolism. In recent years, (intermittent) fasting protocols have also become popular to improve metabolic health. Here, we aimed to investigate the impact of food intake on the 24h patterns of energy metabolism as well as to provide data on the timeline of changes in energy metabolism that occur upon an extended period of fasting.

Invasive and noninvasive markers of human skeletal muscle mitochondrial function.

Mitochondria are organelles that fuel cellular energy requirements by ATP formation via aerobic metabolism. Given the wide variety of methods to assess skeletal muscle mitochondrial capacity, we tested how well different invasive and noninvasive markers of skeletal muscle mitochondrial capacity reflect mitochondrial respiration in permeabilized muscle fibers. Nineteen young men (mean age: 24 ± 4 years) were recruited, and a muscle biopsy was collected to determine mitochondrial respiration from permeabilized muscle fibers and to quantify markers of mitochondrial capacity, content such as citrate synthase (CS) activity, mitochondrial DNA copy number, TOMM20, VDAC, and protein content for complex I-V of the oxidative phosphorylation (OXPHOS) system.

SIRT3 overexpression in rat muscle does not ameliorate peripheral insulin resistance.

Reduced expression of the NAD+-dependent deacetylase, SIRT3, has been associated with insulin resistance and metabolic dysfunction in humans and rodents. In this study, we investigated whether specific overexpression of SIRT3 in vivo in skeletal muscle could prevent high-fat diet (HFD)-induced muscle insulin resistance. To address this, we used a muscle-specific adeno-associated virus (AAV) to overexpress SIRT3 in rat tibialis and extensor digitorum longus (EDL) muscles.

A metabolomic signature of decelerated physiological aging in human plasma.

The degenerative processes that occur during aging increase the risk of disease and impaired health. Meanwhile, interventions that target aging to promote healthy longevity are gaining interest, both academically and in the public. While nutritional and physical interventions exist, efficacy is often difficult to determine.

PCr/ATP ratios and mitochondrial function in the heart. A comparative study in humans.

Cardiac energy status, measured as phosphocreatine (PCr)/adenosine triphosphate (ATP) ratio with 31P-Magnetic Resonance Spectroscopy (31P-MRS) in vivo, is a prognostic factor in heart failure and is lowered in cardiometabolic disease. It has been suggested that, as oxidative phosphorylation is the major contributor to ATP synthesis, PCr/ATP ratio might be a reflection of cardiac mitochondrial function. The objective of the study was to investigate whether PCr/ATP ratios can be used as in vivo marker for cardiac mitochondrial function.

Twenty-four hour rhythmicity in mitochondrial network connectivity and mitochondrial respiration; a study in human skeletal muscle biopsies of young lean and older individuals with obesity.

Mitochondrial network dynamics may play role in metabolic homeostasis. Whether mitochondrial network dynamics are involved in adaptations to day-night fluctuations in energy supply and demand is unclear. Here we visualized and quantified the mitochondrial network morphology in human skeletal muscle of young healthy lean and older individuals with obesity over the course of 24 h METHODS: Muscle biopsies taken at 5 timepoints over a 24-hour period obtained from young healthy lean and older metabolically impaired obese males were analyzed for mitochondrial network integrity with confocal laser scanning microscopy.

Physiological and molecular mechanisms of cold-induced improvements in glucose homeostasis in humans beyond brown adipose tissue.

Exposure to low ambient temperatures has previously been demonstrated to markedly improve glucose homeostasis in both rodents and humans. Although the brown adipose tissue is key in mediating these beneficial effects in rodents, its contribution appears more limited in humans. Hence, the exact tissues and underlying mechanisms that mediate cold-induced improvements in glucose homeostasis in humans remain to be fully established.

Effect of β2-agonist treatment on insulin-stimulated peripheral glucose disposal in healthy men in a randomised placebo-controlled trial.

β-agonist treatment improves skeletal muscle glucose uptake and whole-body glucose homeostasis in rodents, likely via mTORC2-mediated signalling. However, human data on this topic is virtually absent. We here investigate the effects of two-weeks treatment with the β-agonist clenbuterol (40 µg/day) on glucose control as well as energy- and substrate metabolism in healthy young men (age: 18-30 years, BMI: 20-25 kg/m) in a randomised, placebo-controlled, double-blinded, cross-over study (ClinicalTrials.

Skeletal muscle mitochondrial inertia is associated with carnitine acetyltransferase activity and physical function in humans.

BACKGROUNDAt the onset of exercise, the speed at which phosphocreatine (PCr) decreases toward a new steady state (PCr on-kinetics) reflects the readiness to activate mitochondrial ATP synthesis, which is secondary to Acetyl-CoA availability in skeletal muscle. We hypothesized that PCr on-kinetics are slower in metabolically compromised and older individuals and are associated with low carnitine acetyltransferase (CrAT) protein activity and compromised physical function.METHODSWe applied 31P-magnetic resonance spectroscopy (31P-MRS) to assess PCr on-kinetics in 2 cohorts of volunteers.

Effects of SGLT2 inhibitor dapagliflozin in patients with type 2 diabetes on skeletal muscle cellular metabolism.

Objective: SGLT2 inhibitors increase urinary glucose excretion and have beneficial effects on cardiovascular and renal outcomes; the underlying mechanism may be metabolic adaptations due to urinary glucose loss. Here, we investigated the cellular and molecular effects of 5 weeks of dapagliflozin treatment on skeletal muscle metabolism in type 2 diabetes patients.

Methods: Twenty-six type 2 diabetes mellitus patients were randomized to a 5-week double-blind, cross-over study with 6-8-week wash-out.

Three weeks of time-restricted eating improves glucose homeostasis in adults with type 2 diabetes but does not improve insulin sensitivity: a randomised crossover trial.

Aims/hypothesis: Time-restricted eating (TRE) is suggested to improve metabolic health by limiting food intake to a defined time window, thereby prolonging the overnight fast. This prolonged fast is expected to lead to a more pronounced depletion of hepatic glycogen stores overnight and might improve insulin sensitivity due to an increased need to replenish nutrient storage. Previous studies showed beneficial metabolic effects of 6-8 h TRE regimens in healthy, overweight adults under controlled conditions.

A randomized placebo-controlled clinical trial for pharmacological activation of BCAA catabolism in patients with type 2 diabetes.

Elevations in plasma branched-chain amino acid (BCAA) levels associate with insulin resistance and type 2 diabetes (T2D). Pre-clinical models suggest that lowering BCAA levels improve glucose tolerance, but data in humans are lacking. Here, we used sodium phenylbutyrate (NaPB), an accelerator of BCAA catabolism, as tool to lower plasma BCAA levels in patients with T2D, and evaluate its effect on metabolic health.

Healthy aging and muscle function are positively associated with NAD abundance in humans.

Skeletal muscle is greatly affected by aging, resulting in a loss of metabolic and physical function. However, the underlying molecular processes and how (lack of) physical activity is involved in age-related metabolic decline in muscle function in humans is largely unknown. Here, we compared, in a cross-sectional study, the muscle metabolome from young to older adults, whereby the older adults were exercise trained, had normal physical activity levels or were physically impaired.

The influence of bright and dim light on substrate metabolism, energy expenditure and thermoregulation in insulin-resistant individuals depends on time of day.

Aims/hypothesis: In our modern society, artificial light is available around the clock and most people expose themselves to electrical light and light-emissive screens during the dark period of the natural light/dark cycle. Such suboptimal lighting conditions have been associated with adverse metabolic effects, and redesigning indoor lighting conditions to mimic the natural light/dark cycle more closely holds promise to improve metabolic health. Our objective was to compare metabolic responses to lighting conditions that resemble the natural light/dark cycle in contrast to suboptimal lighting in individuals at risk of developing metabolic diseases.