The present results demonstrate the successful application of integrated PET/MRI imaging for whole-body tumor staging of cervical cancer patients, enabling improved treatment planning when compared to MRI alone.
OBJECTIVE Individuals with type 2 diabetes are at higher risk of progression of nonalcoholic fatty liver (steatosis) to steatohepatitis (NASH), fibrosis, and cirrhosis. The hepatic metabolism of obese individuals adapts by upregulation of mitochondrial capacity, which may be lost during the progression of steatosis. However, the role of type 2 diabetes with regard to hepatic mitochondrial function in NASH remains unclear. RESEARCH DESIGN AND METHODS We therefore examined obese individuals with histologically proven NASH without (OBE) (n = 30; BMI 52 ± 9 kg/m2) or with type 2 diabetes (T2D) (n = 15; 51 ± 7 kg/m2) as well as healthy individuals without liver disease (CON) (n = 14; 25 ± 2 kg/m2). Insulin sensitivity was measured by hyperinsulinemic-euglycemic clamps with D-[6,6-2H2]glucose. Liver biopsies were used for assessing mitochondrial capacity by high-resolution respirometry and protein expression. RESULTS T2D and OBE had comparable hepatic fat content, lobular inflammation, and fibrosis. Oxidative capacity in liver tissue normalized for citrate synthase activity was 59% greater in OBE than in CON, whereas T2D presented with 33% lower complex II–linked oxidative capacity than OBE and higher H2O2 production than CON. Interestingly, those with NASH and hepatic fibrosis score ≥1 had lower oxidative capacity and antioxidant defense than those without fibrosis. CONCLUSIONS Loss of hepatic mitochondrial adaptation characterizes NASH and type 2 diabetes or hepatic fibrosis and may thereby favor accelerated disease progression.
BACKGROUND.While saturated fat intake leads to insulin resistance and nonalcoholic fatty liver, Mediterranean-like diets enriched in monounsaturated fatty acids (MUFA) may have beneficial effects. This study examined effects of MUFA on tissue-specific insulin sensitivity and energy metabolism. METHODS.A randomized placebo-controlled cross-over study enrolled 16 glucose-tolerant volunteers to receive either oil (OIL, ~1.18 g/kg), rich in MUFA, or vehicle (VCL, water) on 2 occasions. Insulin sensitivity was assessed during preclamp and hyperinsulinemic-euglycemic clamp conditions. Ingestion of 2 H 2 O/acetaminophen was combined with [6,6-2 H 2 ]glucose infusion and in vivo 13 C/ 31 P/ 1 H/ ex vivo 2 H-magnet resonance spectroscopy to quantify hepatic glucose and energy fluxes. RESULTS.OIL increased plasma triglycerides and oleic acid concentrations by 44% and 66% compared with VCL. Upon OIL intervention, preclamp hepatic and whole-body insulin sensitivity markedly decreased by 28% and 27%, respectively, along with 61% higher rates of hepatic gluconeogenesis and 32% lower rates of net glycogenolysis, while hepatic triglyceride and ATP concentrations did not differ from VCL. During insulin stimulation hepatic and whole-body insulin sensitivity were reduced by 21% and 25%, respectively, after OIL ingestion compared with that in controls. CONCLUSION.A single MUFA-load suffices to induce insulin resistance but affects neither hepatic triglycerides nor energy-rich phosphates. These data indicate that amount of ingested fat, rather than its composition, primarily determines the development of acute insulin resistance. TRIAL REGISTRATION. ClinicalTrials.gov NCT01736202.
Aims/hypothesis Energy-dense nutrition generally induces insulin resistance, but dietary composition may differently affect glucose metabolism. This study investigated initial effects of monounsaturated vs saturated lipid meals on basal and insulin-stimulated myocellular glucose metabolism and insulin signalling. Methods In a randomised crossover study, 16 lean metabolically healthy volunteers received single meals containing safflower oil (SAF), palm oil (PAL) or vehicle (VCL). Whole-body glucose metabolism was assessed from glucose disposal (Rd) before and during hyperinsulinaemic–euglycaemic clamps with d-[6,6-2H2]glucose. In serial skeletal muscle biopsies, subcellular lipid metabolites and insulin signalling were measured before and after meals. Results SAF and PAL raised plasma oleate, but only PAL significantly increased plasma palmitate concentrations. SAF and PAL increased myocellular diacylglycerol and activated protein kinase C (PKC) isoform θ (p < 0.05) but only PAL activated PKCɛ. Moreover, PAL led to increased myocellular ceramides along with stimulated PKCζ translocation (p < 0.05 vs SAF). During clamp, SAF and PAL both decreased insulin-stimulated Rd (p < 0.05 vs VCL), but non-oxidative glucose disposal was lower after PAL compared with SAF (p < 0.05). Muscle serine1101-phosphorylation of IRS-1 was increased upon SAF and PAL consumption (p < 0.05), whereas PAL decreased serine473-phosphorylation of Akt more than SAF (p < 0.05). Conclusions/interpretation Lipid-induced myocellular insulin resistance is likely more pronounced with palmitate than with oleate and is associated with PKC isoforms activation and inhibitory insulin signalling. Trial registration ClinicalTrials.gov.NCT01736202. Funding German Federal Ministry of Health, Ministry of Culture and Science of the State North Rhine-Westphalia, German Federal Ministry of Education and Research, European Regional Development Fund, German Research Foundation, German Center for Diabetes Research. Graphical abstract
Excessive neutrophil activation accompanied by delayed apoptotic cell death in inflammatory conditions causes progressive damage of cells and tissues, leading to life-threatening multiple organ dysfunction syndrome. Previous work suggested that circulating serum factors during inflammation are critically involved in the suppression of neutrophil cell death although the identity of these antiapoptotic mediators remained elusive. In this study, we identified the acute phase protein α-1 Antitrypsin (AAT) as a potent suppressor of staurosporine (STS)-induced apoptosis in human neutrophils through a mechanism implicating caspases-independent pathways. We show here that serum levels of AAT, potentially in part released by stimulated neutrophils, are markedly elevated in major trauma patients suffering from systemic inflammatory response syndrome (SIRS). Notably, AAT depletion from serum increased sensitivity of human neutrophils for STS-induced cell death. In fact, AAT was demonstrated to confer intrinsic apoptosis resistance by preventing PKC/Akt inactivation and subsequent proteasomal degradation of antiapoptotic Mcl-1 protein in response to STS treatment. Neither MAP kinase ERK1/2 nor caspases were found to be involved in AAT-triggered antiapoptotic pathways in neutrophils. In summary, these results establish a novel pivotal role of circulating AAT in mediating survival by antagonizing the proapoptotic action of the PKC inhibitor STS and should be considered for AAT augmentation therapies in future.
Aims/hypothesis Hyperbaric oxygen (HBO) therapy may improve hyperglycaemia in humans with type 2 diabetes, but underlying mechanisms are unclear. Our objective was to examine the glucometabolic effects of HBO on whole-body glucose disposal in humans with type 2 diabetes. Methods In a randomised placebo-controlled crossover trial located at the German Diabetes Center, 12 male individuals with type 2 diabetes (age 18–75 years, BMI <35 kg/m2, HbA1c 42–75 mmol/mol [6–9%]), randomly allocated by one person, underwent 2-h HBO, once with 100% (240 kPa; HBO) and once with 21% oxygen (240 kPa; control, CON). Insulin sensitivity was assessed by hyperinsulinaemic–euglycaemic clamps with d-[6,6-2H2]glucose, hepatic and skeletal muscle energy metabolism were assessed by 1H/31P-magnetic resonance spectroscopy, while high-resolution respirometry measured skeletal muscle and white adipose tissue (WAT) mitochondrial capacity. All participants and people assessing the outcomes were blinded. Results HBO decreased fasting blood glucose by 19% and increased whole-body, hepatic and WAT insulin sensitivity about one-third (p<0.05 vs CON). Upon HBO, hepatic γ-ATP concentrations doubled, mitochondrial respiratory control doubled in skeletal muscle and tripled in WAT (p<0.05 vs CON). HBO increased myocellular insulin-stimulated serine-473/threonine-308 phosphorylation of Akt but decreased basal inhibitory serine-1101 phosphorylation of IRS-1 and endoplasmic reticulum stress (p<0.05 vs CON). Conclusions/interpretation HBO-mediated improvement of insulin sensitivity likely results from decreased endoplasmic reticulum stress and increased mitochondrial capacity, possibly leading to low-dose reactive oxygen species-mediated mitohormesis in humans with type 2 diabetes. Trial registration ClinicalTrials.gov NCT04219215 Funding German Federal Ministry of Health, German Federal Ministry of Education and Research, North-Rhine Westfalia Ministry of Culture and Science, European-Regional-Development-Fund, German-Research-Foundation (DFG), Schmutzler Stiftung Graphical abstract
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