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).
View Article and Find Full Text PDFBackground: Brown adipose tissue (BAT) has been primarily researched as a potential target for mitigating obesity. However, the physiological significance of BAT in relation to cachexia remains poorly understood. The objective of this study was to investigate the putative contribution of BAT on different components of energy metabolism in emphysematous chronic obstructive pulmonary disease (COPD) patients.
View Article and Find Full Text PDFAims/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.
View Article and Find Full Text PDFPurpose: Resveratrol has shown promising anti-inflammatory effects in in vitro and animal studies. We aimed to investigate this effect on arterial inflammation in vivo.
Methods: This was an additional analysis of a double-blind randomized crossover trial which included eight male subjects with decreased insulin sensitivity who underwent an F-fluoroxyglucose (F-FDG) PET/CT after 34 days of placebo and resveratrol treatment (150 mg/day).
Mild cold acclimation for 10 days has been previously shown to markedly improve insulin sensitivity in patients with type 2 diabetes. Here we show in a single-arm intervention study (Trialregister.nl ID: NL4469/NTR5711) in nine patients with type 2 diabetes that ten days of mild cold acclimation (16-17 °C) in which observable, overt shivering was prevented, does not result in improved insulin sensitivity, postprandial glucose and lipid metabolism or intrahepatic lipid content and only results in mild effects on overnight fasted fat oxidation, postprandial energy expenditure and aortic augmentation index.
View Article and Find Full Text PDFContext: Elevating nicotinamide adenine dinucleotide (NAD+) levels systemically improves metabolic health, which can be accomplished via nicotinamide riboside (NR). Previously, it was demonstrated that NR supplementation in high-fat-diet (HFD)-fed mice decreased weight gain, normalized glucose metabolism, and enhanced cold tolerance.
Objective: Because brown adipose tissue (BAT) is a major source of thermogenesis, we hypothesize that NR stimulates BAT in mice and humans.
Creatine availability in adipose tissue has been shown to have profound effects on thermogenesis and energy balance in mice. However, whether dietary creatine supplementation affects brown adipose tissue (BAT) activation in humans is unclear. In the present study, we report the results of a double-blind, randomized, placebo-controlled, cross-over trial (NCT04086381) in which 14 young, healthy, vegetarian adults, who are characterized by low creatine levels, received 20 g of creatine monohydrate per day or placebo.
View Article and Find Full Text PDFMuscle glycogen use and glucose uptake during cold exposure increases with shivering intensity. We hypothesized that cold exposure, with shivering, would subsequently increase glucose tolerance. Fifteen healthy men (age = 26 ± 5 yr, body mass index = 23.
View Article and Find Full Text PDFBackground: Cold acclimation and exercise training were previously shown to increase peripheral insulin sensitivity in human volunteers with type 2 diabetes. Although cold is a potent activator of brown adipose tissue, the increase in peripheral insulin sensitivity by cold is largely mediated by events occurring in skeletal muscle and at least partly involves GLUT4 translocation, as is also observed for exercise training.
Methods: To investigate if cold acclimation and exercise training overlap in the molecular adaptive response in skeletal muscle, we performed transcriptomics analysis on vastus lateralis muscle collected from human subjects before and after 10 days of cold acclimation, as well as before and after a 12-week exercise training intervention.
The purpose of this study was to assess the impact of postexercise hot-water immersion on postprandial myofibrillar protein synthesis rates during recovery from a single bout of resistance-type exercise in healthy, young men. Twelve healthy, adult men (age: 23 ± 1 y) performed a single bout of resistance-type exercise followed by 20 min of water immersion of both legs. One leg was immersed in hot water [46°C: hot-water immersion (HWI)], while the other leg was immersed in thermoneutral water (30°C: CON).
View Article and Find Full Text PDFKey Points: Protein ingestion and cooling are strategies employed by athletes to improve postexercise recovery and, as such, to facilitate muscle conditioning. However, whether cooling affects postprandial protein handling and subsequent muscle protein synthesis rates during recovery from exercise has not been assessed. We investigated the effect of postexercise cooling on the incorporation of dietary protein-derived amino acids into muscle protein and acute postprandial (hourly) as well as prolonged (daily) myofibrillar protein synthesis rates during recovery from resistance-type exercise over 2 weeks.
View Article and Find Full Text PDFBackground: Vagus nerve activation impacts inflammation. Therefore, we hypothesized that vagal nerve stimulation (VNS) influenced arterial wall inflammation as measured by F-FDG uptake.
Results: Ten patients with left-sided VNS for refractory epilepsy were studied during stimulation (VNS-on) and in the hours after stimulation was switched off (VNS-off).
Background: South Asians generally have an unfavourable metabolic phenotype compared with white Caucasians, including central obesity and insulin resistance. The Wnt protein family interacts with insulin signaling, and impaired Wnt signaling is associated with adiposity and type 2 diabetes mellitus. We aimed to investigate Wnt signaling in relation to insulin signaling in South Asians compared with white Caucasians.
View Article and Find Full Text PDFThe widespread use of electric light and electronic devices has resulted in an excessive exposure to light during the late-evening and at night. This late light exposure acutely suppresses melatonin and sleepiness and delays the circadian clock. Here we investigate whether the acute effects of late-evening light exposure on our physiology and sleepiness are reduced when this light exposure is preceded by early evening bright light.
View Article and Find Full Text PDFThe quality of local skin temperature prediction by thermophysiological models depends on the local skin blood flow (SBF) control functions. These equations were derived for low activity levels (0.8-1met) and mostly in sitting or supine position.
View Article and Find Full Text PDFPurpose: Lowering of LDL cholesterol levels by plant sterols and stanols is associated with decreased risk of cardiovascular disease in humans. Plant sterols and stanols also lower triacylglycerol (TG). However, it is not fully understood how reduction in TG is achieved and what the full potential of plant sterols and stanols is on whole-body metabolism.
View Article and Find Full Text PDFPurpose: We aimed to investigate the influence of both hypothyroidism and thyroid-stimulating hormone (TSH) suppression on vascular inflammation, as assessed with F-fluorodeoxyglucose (F-FDG) positron emission tomography (PET)/computed tomography (CT).
Methods: Ten thyroid carcinoma patients underwent an F-FDG PET/CT during post-thyroidectomy hypothyroidism and during thyrotropin (TSH) suppression after I (radioiodine) ablation therapy. We analysed the F-FDG uptake in the carotids, aortic arch, ascending, descending, and abdominal aorta to investigate the effects of thyroid hormone status on arterial inflammation.
Madelung's disease is characterized by the manifestation of multiple ectopic lipomas, usually found in the cervical-thoracic region, however, clinical manifestation may vary among patients. It has been postulated that lipomas associated with Madelung's disease are linked to brown adipose tissue (BAT) due to the presence of uncoupling protein 1 (UCP1). Therefore, we here investigated whether BAT activity is present in a patient with Madelung's disease.
View Article and Find Full Text PDFBrown adipose tissue (BAT) is present in human adults and the current gold standard to visualize and quantify BAT is [F]FDG PET-CT. However, this method fails to detect BAT under insulin-resistant conditions associated with ageing and weight gain, such as type 2 diabetes. The aim of this study was to develop a novel triglyceride-based tracer for BAT.
View Article and Find Full Text PDFDiabetologia
January 2019
Aims/hypothesis: Individuals of South Asian origin are at increased risk of developing type 2 diabetes mellitus and associated comorbidities compared with Europids. Disturbances in energy metabolism may contribute to this increased risk. Skeletal muscle and possibly also brown adipose tissue (BAT) are involved in human energy metabolism and nitric oxide (NO) is suggested to play a pivotal role in regulating mitochondrial biogenesis in both tissues.
View Article and Find Full Text PDFObjective: The study aimed to investigate whether markers of endocannabinoid signaling differed between men with overweight of South Asian and white Caucasian descent.
Methods: We included South Asian (n = 10) and white Caucasian (n = 10) men with overweight and prediabetes aged 35 to 50 years. Plasma samples were analyzed for endocannabinoids, their congeners, and lipids.
Circadian misalignment, such as in shift work, has been associated with obesity and type 2 diabetes. However, direct effects of circadian misalignment on skeletal muscle insulin sensitivity and the muscle molecular circadian clock have never been studied in humans. Here, we investigated insulin sensitivity and muscle metabolism in 14 healthy young lean men [age 22.
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