Correction to: Identification of an intracellular metabolic signature impairing beta cell function in the rat beta cell line INS-1E and human islets.

As part of an institutional investigation by University of Bremen, the work carried out by Kathrin Maedler's laboratory has been reviewed.

EFhd2/Swiprosin-1 is a common genetic determinator for sensation-seeking/low anxiety and alcohol addiction.

In many societies, the majority of adults regularly consume alcohol. However, only a small proportion develops alcohol addiction. Individuals at risk often show a high sensation-seeking/low-anxiety behavioural phenotype. Here we asked which role EF hand domain containing 2 (EFhd2; Swiprosin-1) plays in the control of alcohol addiction-associated behaviours. EFhd2 knockout (KO) mice drink more alcohol than controls and spontaneously escalate their consumption. This coincided with a sensation-seeking and low-anxiety phenotype. A reversal of the behavioural phenotype with ß-carboline, an anxiogenic inverse benzodiazepine receptor agonist, normalized alcohol preference in EFhd2 KO mice, demonstrating an EFhd2-driven relationship between personality traits and alcohol preference. These findings were confirmed in a human sample where we observed a positive association of the EFhd2 single-nucleotide polymorphism rs112146896 with lifetime drinking and a negative association with anxiety in healthy adolescents. The lack of EFhd2 reduced extracellular dopamine levels in the brain, but enhanced responses to alcohol. In confirmation, gene expression analysis revealed reduced tyrosine hydroxylase expression and the regulation of genes involved in cortex development, Eomes and Pax6, in EFhd2 KO cortices. These findings were corroborated in Xenopus tadpoles by EFhd2 knockdown. Magnetic resonance imaging (MRI) in mice showed that a lack of EFhd2 reduces cortical volume in adults. Moreover, human MRI confirmed the negative association between lifetime alcohol drinking and superior frontal gyrus volume. We propose that EFhd2 is a conserved resilience factor against alcohol consumption and its escalation, working through Pax6/Eomes. Reduced EFhd2 function induces high-risk personality traits of sensation-seeking/low anxiety associated with enhanced alcohol consumption, which may be related to cortex function.

Specific skeletal muscle sphingolipid compounds in energy expenditure regulation and weight gain in Native Americans of Southwestern heritage.

BACKGROUND/OBJECTIVES: In animal models, a role in the regulation of energy expenditure (EE) has been ascribed to sphingolipids, active components of cell membranes participating in cellular signaling. In humans, it is unknown whether sphingolipids have a role in the modulation of EE and, consequently, influence weight gain. The present study investigated the putative association of EE and weight gain with sphingolipid levels in the human skeletal muscle, a component of fat-free mass (the strongest determinant of EE), in adipose tissue and plasma. SUBJECTS/METHODS: Twenty-four-hour EE, sleeping metabolic rate (SMR) and resting metabolic rate (RMR) were assessed in 35 healthy Native Americans of Southwestern heritage (24 male; 30.2±7.73 years). Sphingolipid (ceramide, C; sphingomyelin, SM) concentrations were measured in skeletal muscle tissue, subcutaneous adipose tissue and plasma samples. After 6.68 years (0.26-12.4 years), follow-up weights were determined in 16 participants (4 females). RESULTS: Concentrations of C24:0, SM18:1/26:1 and SM18:0/24:1 in muscle were associated with 24-h EE (r=-0.47, P=0.01), SMR (r=-0.59, P=0.0008) and RMR (r=-0.44, P=0.01), respectively. Certain muscle sphingomyelins also predicted weight gain (for example, SM18:1/23:1, r=0.74, P=0.004). For specific muscle sphingomyelins that correlated with weight gain and EE (SM18:1/23:0, SM18:1/23:1 and SMR, r=-0.51, r=-0.41, respectively, all P<0.03; SM18:1/24:2 and RMR, r=-0.36, P=0.03), associations could be reproduced with SMR in adipose tissue (all r<-0.46, all P<0.04), though not in plasma. CONCLUSIONS: This study provides preliminary, novel evidence, that specific muscle and adipose tissue sphingolipid compounds are associated with EE and weight gain in Native Americans of Southwestern heritage. Further studies are warranted to investigate whether sphingolipids of different body compartments act in concert to modulate energy balance in humans.

Exercise prevents high-fat diet-induced impairment of flexible memory expression in the water maze and modulates adult hippocampal neurogenesis in mice.

Obesity is currently one of the most serious threats to human health in the western civilization. A growing body of evidence suggests that obesity is associated with cognitive dysfunction. Physical exercise not only improves fitness but it has also been shown in human and animal studies to increase hippocampus-dependent learning and memory. High-fat diet (HFD)-induced obesity and physical exercise both modulate adult hippocampal neurogenesis. Adult neurogenesis has been demonstrated to play a role in hippocampus-dependent learning and memory, particularly flexible memory expression. Here, we investigated the effects of twelve weeks of HFD vs. control diet (CD) and voluntary physical activity (wheel running; -R) vs. inactivity (sedentary; -S) on hippocampal neurogenesis and spatial learning and flexible memory function in female C57Bl/6 mice assessed in the Morris water maze. HFD was initiated either in adolescent mice combined with long-term concurrent exercise (preventive approach) or in young adult mice with 14days of subsequent exercise (therapeutic approach). HFD resulted in impaired flexible memory expression only when initiated in adolescent (HFD-S) but not in young adult mice, which was successfully prevented by concurrent exercise (HFD-R). Histological analysis revealed a reduction of immature neurons in the hippocampus of the memory-impaired HFD-S mice of the preventive approach. Long-term physical exercise also led to accelerated spatial learning during the acquisition period, which was accompanied by increased numbers of newborn mature neurons (HFD-R and CD-R). Short-term exercise of 14days in the therapeutic group was not effective in improving spatial learning or memory. We show that (1) alterations in learning and flexible memory expression are accompanied by changes in the number of neuronal cells at different maturation stages; (2) these neuronal cells are in turn differently affected by HFD; (3) adolescent mice are specifically susceptible to the negative effects of HFD. Thus, physical exercise, by modulating adult neurogenesis in the hippocampus, might represent a potential preventive approach for treating cognitive impairments associated with adolescent obesity.

Kniest and Stickler dysplasia phenotypes caused by collagen type II gene (COL2A1) defect.

Kniest and Stickler dysplasia are two chondrodysplasias characterized by specific phenotypes. No basic defect has been found in patients with Kniest dysplasia, whereas Stickler dysplasia is one of four chondrodysplasias for which mutations of type II procollagen gene (COL2A1) have been identified. We studied a 2-year-old girl presenting with manifestations of Kniest dysplasia and her mother showing a Stickler phenotype. Analysing COL2A1 in both patients, we detected the same 28 basepair deletion spanning the 3'-exon/intron boundary of exon 12 in mother and daughter. We were able to prove a somatic mosaic status for this mutation in the mother which accounts for her milder Stickler-like phenotype.

Leptin and endocrine parameters in marathon runners.

Endurance training may lead to different hormonal alterations e. g., exercised induced hypothalamic ovarian/testicular dysfunction. The aim of this study was to reveal new connections between physical exercise, leptin and hormonal responses. 36 male participants of the Berlin-Marathon had their blood samples taken 2 days before the marathon. Hormones of the hypothalamic-pituitary axis and leptin were correlated with the training status and the achieved marathon time. Leptin correlated with the achieved marathon time after being adjusted for age and BMI (r=0.607, p<0.001) and was lowest in the best trained runners. Additionally, when the group was divided into quartiles of their achieved marathon time, significantly increased cortisol, fT4, cortisol/DHEAS ratio and decreased IGF-1 levels were observed in the slowest group. In the better trained group, a decrease of testosterone/DHT ratio and an increase of testosterone/cortisol ratio were observed. Our study supports the thesis of a linear relationship between physical fitness and leptin variations in the physiological range. We found an increased anabolic hormonal response in well trained marathon runners and hormonal reactions of increased stress in less trained runners. As the stress-induced neuroendocrine adaptations in our study group are associated with more higher leptin values, the pathophysiological role of decreased leptin values seems to be limited to overtrained athletes.

Identification of an intracellular metabolic signature impairing beta cell function in the rat beta cell line INS-1E and human islets.

AIMS/HYPOTHESIS: Chronic hyperglycaemia promotes the progressive failure of pancreatic beta cells in patients with type 2 diabetes mellitus, a clinically highly relevant phenomenon known as glucotoxicity. The intracellular metabolic consequences of a chronically high availability of glucose in beta cells are, as yet, poorly understood in its full complexity. METHODS: An unbiased metabolite profiling analysis (GC-time-of-flight-MS) was used to identify the time course of core metabolite patterns in rat beta cell line INS-1E during exposure to high glucose concentrations and its relation to insulin expression. RESULTS: We report here that pentose phosphate pathway (PPP) metabolites accumulate remarkably during chronic but not acute glucose treatment, indicating altered processing of glucose through the pentose phosphate pathway. Subsequent functional studies in INS-1E cells and human islets revealed that a disturbance in this pathway contributes to decreases in insulin gene expression and a lack of glucose-stimulated insulin secretion. These effects were found to depend on the activation of extracellular-regulated-kinase (ERK1/2). Long-term inhibition of 6-phosphogluconic acid dehydrogenase resulted in accumulation of PPP metabolites, induced ERK1/2 activation independently of high glucose and impaired beta cell function. In turn, inhibition of ERK1/2 overstimulation during chronic glucose exposure partly inhibited metabolite accumulation and restored beta cell function. CONCLUSIONS/INTERPRETATION: Based on unbiased metabolite analyses, the data presented here provide novel targets, namely the inhibition of PPP metabolite accumulation towards the therapeutic goal to preserve and potentially improve beta cell function in diabetes.

Design and cohort description of the InterAct Project: an examination of the interaction of genetic and lifestyle factors on the incidence of type 2 diabetes in the EPIC Study.

AIMS/HYPOTHESIS: Studying gene-lifestyle interaction may help to identify lifestyle factors that modify genetic susceptibility and uncover genetic loci exerting important subgroup effects. Adequately powered studies with prospective, unbiased, standardised assessment of key behavioural factors for gene-lifestyle studies are lacking. This case-cohort study aims to investigate how genetic and potentially modifiable lifestyle and behavioural factors, particularly diet and physical activity, interact in their influence on the risk of developing type 2 diabetes. METHODS: Incident cases of type 2 diabetes occurring in European Prospective Investigation into Cancer and Nutrition (EPIC) cohorts between 1991 and 2007 from eight of the ten EPIC countries were ascertained and verified. Prentice-weighted Cox regression and random-effects meta-analyses were used to investigate differences in diabetes incidence by age and sex. RESULTS: A total of 12,403 verified incident cases of type 2 diabetes occurred during 3.99 million person-years of follow-up of 340,234 EPIC participants eligible for InterAct. We defined a centre-stratified subcohort of 16,154 individuals for comparative analyses. Individuals with incident diabetes who were randomly selected into the subcohort (n = 778) were included as cases in the analyses. All prevalent diabetes cases were excluded from the study. InterAct cases were followed-up for an average of 6.9 years; 49.7% were men. Mean baseline age and age at diagnosis were 55.6 and 62.5 years, mean BMI and waist circumference values were 29.4 kg/m(2) and 102.7 cm in men, and 30.1 kg/m(2) and 92.8 cm in women, respectively. Risk of type 2 diabetes increased linearly with age, with an overall HR of 1.56 (95% CI 1.48-1.64) for a 10 year age difference, adjusted for sex. A male excess in the risk of incident diabetes was consistently observed across all countries, with a pooled HR of 1.51 (95% CI 1.39-1.64), adjusted for age. CONCLUSIONS/INTERPRETATION: InterAct is a large, well-powered, prospective study that will inform our understanding of the interplay between genes and lifestyle factors on the risk of type 2 diabetes development.

Effects of hyperlipidaemia on glucocorticoid metabolism: results of a randomized controlled trial in healthy young women.

OBJECTIVE: It is well established that the hypothalamic-pituitary-adrenal (HPA) axis is altered in obese individuals. Hyperlipidaemia with elevated levels of free fatty acids (FFAs) is also frequently seen in obesity and in the metabolic syndrome. We hypothesized, therefore, that hyperlipidaemia may alter the activity of the HPA axis. PATIENTS AND METHODS: The effects of hyperlipidaemia, including increased circulating FFAs, on ACTH secretion and cortisol metabolism were analysed in 13 healthy young women during the early follicular phase of two subsequent cycles. We administered a 20% lipid/heparin (LHI) or a saline/heparin infusion (SHI) using a crossover design in random order for 330 min. A detailed characterization of glucocorticoid metabolism was performed by measurement of plasma ACTH, cortisol and urinary excretion rates of adrenal glucocorticoids and the glucocorticoid metabolites. RESULTS: We observed that LHI-induced hyperlipidaemia elevated serum cortisol levels compared to SHI. No changes in plasma ACTH levels, daily urinary excretion rates of adrenal glucocorticoids, glucocorticoid precursors/metabolites and the calculated activities of the 5α-reductase, 3ß-hydroxysteroid dehydrogenase (HSD), 11-, 17-, 21-hydroxylase and 11ß-HSD 1 or 2 were found. CONCLUSION: Our randomized controlled trial suggests that the adrenal sensitivity to ACTH may be enhanced by LHI-induced hyperlipidaemia in normal-weight healthy young women. This effect might contribute to the disturbances of the HPA axis described in women with abdominal obesity and impaired lipid metabolism.

T3/rT3-ratio is associated with insulin resistance independent of TSH.

Thyroid dysfunction has been shown to be associated with insulin resistance (IR). This may involve peripheral thyroid hormone metabolism, which is assumed to be reflected by the ratio triiodothyronine/reverse triiodothyronine (T3/rT3-ratio). To explore a potential association between the T3/rT3-ratio and IR we investigated pairs which differed in IR, but were matched by sex, age, body mass index (BMI), and thyroid stimulating hormone (TSH). For this purpose, matched pair analyses were embedded into a cross sectional study group. 22 pairs were matched from either the first or the third tertile of HOMA%S of a cohort of 353 euthyroid subjects with normal glucose metabolism who did not take any medication. The T3/rT3-ratio was compared in the matched pairs. The T3/rT3-ratio was significantly increased in the insulin resistant subjects compared to their insulin sensitive partners (8.78 ± 0.47 vs. 7.33 ± 0.33, p=0.019). Furthermore the T3/rT3-ratio was lower in men compared to women (p for the within-subject effect=0.046) both in the insulin sensitive and the insulin resistant subjects. Here we show that the T3/rT3-ratio, which is supposed to reflect the tissue thyroid hormone metabolism, is significantly increased in insulin resistant subjects. This further supports a link between thyroid function and IR.

Annual change in insulin sensitivity.

The incidence of both type 2 diabetes and cardiac events is reported to be higher during winter, indicating a putative annual periodic change in insulin sensitivity (IS). Annual differences in IS - quantified as HOMA-%S and Matsuda-Sensitivity Index - were analyzed using a cosine wave-fitting algorithm in a cross-sectional study group including 2 385 participants. Additionally, semi-annual differences in IS were compared. We found periodicity for HOMA-%S and Matsuda-Sensitivity Index (p=0.02 or 0.006), which was strengthened after restriction to participants without diabetes (p=0.009 or 0.004). The rhythm amplitude of 0.08 indicated moderate changes in IS throughout the year. IS was significantly higher when participants were enrolled during the second vs. the first half of the year (HOMA-%S 112.0±3.0% vs. 97.4±2.4%, p<0.001). The impact of the half-year on IS, which remained significant after adjustment for confounders, was again moderate and explained only 0.5% of the variation. IS showed a significant moderate annual periodicity, which may affect the interpretation of studies reporting small changes in IS.

Improved insulin sensitivity, preserved beta cell function and improved whole-body glucose metabolism after low-dose growth hormone replacement therapy in adults with severe growth hormone deficiency: a pilot study.

AIMS/HYPOTHESIS: Growth hormone-deficient patients show deterioration of insulin sensitivity and beta cell function. High-dose growth hormone treatment often induces further impairment of insulin sensitivity, leading to an increase in insulin and glucose levels or even, in cases of preexisting beta cell defect, to overt diabetes. However, low-dose treatment may improve insulin sensitivity, although data in humans with detailed metabolic phenotyping are as yet not available. We postulated that long-term low-dose growth hormone replacement, restoring IGF-1 to the low-normal range, might beneficially affect glucose metabolism. METHODS: We studied prospectively the metabolic responses to 24 and 48 weeks of growth hormone treatment in a small group of six adults with severe growth hormone deficiency (four men, two women; age 40-59 years; BMI 30.2 +/- 1 kg/m(2); mean growth hormone dose 0.3 +/- 0.04 mg/day). All participants underwent an oral glucose tolerance test, euglycaemic-hyperinsulinaemic clamp and hyperglycaemic-hyperinsulinaemic clamp plus i.v. L: -arginine on three occasions. Insulin sensitivity was measured by calculating the M value during the steady state of the euglycaemic-hyperinsulinaemic clamp. Insulin secretion and clearance were estimated from AUC(C-peptide), AUC(insulin) and their ratio at each phase of the hyperglycaemic-hyperinsulinaemic clamp. RESULTS: Growth hormone significantly improved insulin sensitivity (M value 13.8 +/- 2.6 [baseline] vs 19.6 +/- 2.6 [24 weeks] and 23.7 +/- 1.9 [48 weeks] micromol kg(-1) min(-1); p < 0.01). Although the insulin response to glucose and arginine decreased slightly, the disposition index, integrating insulin sensitivity and secretion, significantly increased (p < 0.01), indicating an improvement in whole-body glucose metabolism. Insulin clearance was not affected during treatment (p > 0.05). CONCLUSIONS/INTERPRETATION: Our data indicate that long-term low-dose growth hormone treatment may improve insulin sensitivity and whole-body glucose metabolism in adults with severe growth hormone-deficiency.

High-fat Diet and Physical Exercise Differentially Modulate Adult Neurogenesis in the Mouse Hypothalamus.

The hypothalamus has emerged as a novel neurogenic niche in the adult brain during the past decade. However, little is known about its regulation and the role hypothalamic neurogenesis might play in body weight and appetite control. High-fat diet (HFD) has been demonstrated to induce an inflammatory response and to alter neurogenesis in the hypothalamus and functional outcome measures, e.g. body weight. Such modulation poses similarities to what is known from adult hippocampal neurogenesis, which is highly responsive to lifestyle factors, such as nutrition or physical exercise. With the rising question of a principle of neurogenic stimulation by lifestyle in the adult brain as a physiological regulatory mechanism of central and peripheral functions, exercise is interventionally applied in obesity and metabolic syndrome conditions, promoting weight loss and improving glucose tolerance and insulin sensitivity. To investigate the potential pro-neurogenic cellular processes underlying such beneficial peripheral outcomes, we exposed adult female mice to HFD together with physical exercise and evaluated neurogenesis and inflammatory markers in the arcuate nucleus (ArcN) of the hypothalamus. We found that HFD increased neurogenesis, whereas physical exercise stimulated cell proliferation. HFD also increased the amount of microglia, which was counteracted by physical exercise. Physiologically, exercise increased food and fat intake but reduced HFD-induced body weight gain. These findings support the hypothesis that hypothalamic neurogenesis may represent a counter-regulatory mechanism in response to environmental or physiological insults to maintain energy balance.

Effects of euglycemic hyperinsulinemia and lipid infusion on circulating cholecystokinin.

AIMS: Functions of the gut hormone cholecystokinin (CCK) include an important role in the regulation of gastric emptying, postprandial glucose homeostasis, and postmeal satiety. Postprandial CCK responses are significantly blunted in type 2 diabetic patients by unknown mechanisms. We hypothesized that hyperinsulinemia and lipid infusion influence circulating levels of biologically active CCK. METHODS: Eleven healthy subjects were studied in a cross-over design after 10-h overnight fasts, using euglycemic-hyperinsulinemic clamps for 443 min, with an additional infusion of lipid-heparin (1.25 ml.min(-1)) or saline (1.25 ml.min(-1)) for the last 300 min after constant plasma glucose levels were achieved. RESULTS: Euglycemic-hyperinsulinemia resulted in a sustained, up to 5-fold increase of plasma CCK (P < 0.001). When adding lipid infusion instead of saline, CCK concentrations rapidly declined and returned to baseline levels (CCK(300 min) 1.1 +/- 0.2 vs. 3.3 +/- 0.3 pmol/liter, P < 0.001). Partial intraclass correlation showed an independent correlation of plasma CCK with free fatty acids (r(ic) = -0.377, P < 0.001) but not with serum insulin (r(ic) = 0.077, P = 0.32). Whole-body insulin sensitivity decreased in lipid-exposed subjects (M value 7.1 +/- 0.7 vs. 5.6 +/- 0.9 mg.kg.min(-1), P = 0.017) but was not independently correlated with CCK (r(ic) = 0.040, P = 0.61). CONCLUSIONS: We report novel findings showing that circulating CCK markedly increased in the euglycemic-hyperinsulinemic state, possibly as a result of near-complete suppression of circulating free fatty acids. Moreover, raising blood lipids even moderately by lipid infusion rapidly and significantly interfered with this effect, suggesting that a negative feedback mechanism of blood lipids on circulating CCK might exist.

Intravenous lipid and heparin infusion-induced elevation in free fatty acids and triglycerides modifies circulating androgen levels in women: a randomized, controlled trial.

BACKGROUND: The polycystic ovarian syndrome (PCOS) is characterized by hyperandrogenism and associated with obesity and impaired glucose metabolism. Despite the high prevalence of PCOS and the considerable clinical impact, the precise interplay between metabolism and hyperandrogenemia is not entirely clear. OBJECTIVE: The objective of the study was to analyze the effects of iv lipid and heparin infusion on circulating androgen levels in healthy women. DESIGN: This was a randomized, controlled, crossover trial. SETTING: The study was conducted at an endocrinology center. PATIENTS: Patients included 12 healthy young women during the early follicular phase of two subsequent cycles. INTERVENTION: After an overnight fast, a 20% lipid/heparin or a saline/heparin infusion was administered in random order for 330 min. MAIN OUTCOME MEASURES: A detailed characterization of androgen metabolism was performed. RESULTS: Elevations in free fatty acids and triglycerides, induced by lipid/heparin infusion, elevates the levels of androstenedione, dehydroepiandrosterone (DHEA), dehydroepiandrosterone sulfate (DHEAS), testosterone, 5alpha-dihydrotestosterone, estrone, and 17beta-estradiol. Urinary excretion of DHEA, DHEAS, 5-androstene-3beta,17beta-diol, and the sum of urinary excreted DHEA and its 16-hydroxylated downstream metabolites, 16alpha-hydroxy-DHEA and 5-androstene-3beta,16alpha,17beta-triol, were reduced. CONCLUSION: The mechanism of iv lipid and heparin infusion-induced elevation of circulating androgens described here might contribute to the development of hyperandrogenism in women with PCOS and suggests that lowering of hyperlipidemia might be a potential therapeutic target in patients with PCOS to treat hyperandrogenemia.

Euglycemic hyperinsulinemia differentially modulates circulating total and acylated-ghrelin in humans.

Ghrelin is a powerful orexigenic gut hormone. Circulating concentrations of total ghrelin are downregulated by food intake in both acute and chronic hyperinsulinemic states. However, in blood des-acylated (des-acyl) ghrelin is the predominant form that has no orexigenic effects in humans. Circulating acyl-ghrelin has been shown to be suppressed post-prandially and by pharmacological hyperinsulinemia. However, up to now responses of circulating acyl-ghrelin to moderate hyperinsulinemic and hyperinsulinemic-hyperlipidemic clamp conditions have not been reported. Fourteen healthy subjects were investigated using two-stepped euglycemic-hyperinsulinemic clamps (40 mU insulin/ m2/min; mean 148+/-7 min till steady state, followed by 300 min lipid/heparin infusion). Responses of total ghrelin and acyl-ghrelin were measured at timed intervals throughout the clamps. Des-acyl-ghrelin concentrations were calculated by subtraction. Total ghrelin significantly decreased vs baseline concentrations (819+/-92 vs 564+/-58 pg/ml, p<0.001), thereby confirming previous observations. Des-acyl ghrelin closely followed total ghrelin concentrations and significantly decreased vs baseline (772+/-92 vs 517+/-56 pg/ml, p<0.001). In contrast, neither euglycemichyperinsulinemia nor euglycemic-hyperinsulinemic- hyperlipidemia suppressed acyl-ghrelin below baseline concentrations throughout the clamps (46+/-3 vs 47+/-8 pg/ml, p=0.90). In conclusion, moderate hyperinsulinemic and hyperinsulinemic- hyperlipidemic clamp conditions differentially modulated circulating total ghrelin and acylghrelin in humans. Factors other than changes in insulin and lipid concentrations are likely to contribute to the previously reported post-prandial reduction of circulating acyl-ghrelin.

Measuring Energy Expenditure in extracorporeal lung support Patients (MEEP) - Protocol, feasibility and pilot trial.

PURPOSE: Indirect calorimetry (IC) is the gold standard for measuring energy expenditure (EE). Due to O2 uptake and CO2 removal by both the extracorporeal lung support (ECLS) membrane and the lungs, a conventional IC is not feasible and no data available. Our MEEP (Measuring Energy Expenditure in ECLS Patients) protocol enables the determination of the REE in patients with ECLS, the comparison to patients without ECLS, and accuracy assessment of estimating equations. METHODS: In the MEEP protocol, a conventional IC is performed and extended by a calculation of the O2 uptake and the CO2 elimination by the ECLS membrane. Sum O2 uptake and CO2 elimination were used in the equation of Weir to calculate EE. We included 20 patients with ARDS on veno-venous (vv)-extracorporeal membrane oxygenation (ECMO) treatment, and 20 matched ARDS patients without ECLS as control. EE measurements were compared to the most prevalent predicting equations for EE. RESULTS: The new MEEP-protocol was shown to be feasible. None of the estimating equations matched the measured EE. Measured EE values did not significantly differ between the ARDS patients with vv-ECMO (2013 kcal/d [1786/2333]) and ARDS patients without ECLS (1857 kcal/d [1602/2085]) (p = 0.165). The blood flow through the vv-ECMO itself did not influence the EE. CONCLUSION: Using the MEEP protocol, EE becomes easily measurable in patients with ECLS. We recommend the implementation of sequential measurements of EE in the critically ill, especially for patients with ECLS, but also for those without, in order to improve goal directed nourishment.

Effect of human body weight changes on circulating levels of peptide YY and peptide YY3-36.

BACKGROUND: Recent findings suggest that low plasma peptide YY (PYY) levels may contribute to diet-induced human obesity and justify PYY replacement therapy. Although the pharmacological value of PYY is controversial, further study of the secretion of the precursor PYY(1-36) and the pharmacologically active PYY(3-36) is indicated to determine the potential role in energy balance regulation. AIM: Our objective was to determine the effects of acute and chronic changes in human body weight on circulating levels of the putative satiety hormone peptide YY. DESIGN: Total plasma PYY levels (PYY(1-36) + PYY(3-36)) were measured in 66 lean, 18 anorectic, 63 obese, and 16 morbidly obese humans. In addition, total PYY was measured in 17 of the obese patients after weight loss and in the 18 anorectic patients after weight gain. Fasting PYY(3-36) levels were measured in 17 lean and 15 obese individuals. RESULTS: Fasting total plasma PYY levels were highest in patients with anorexia nervosa (80.9 +/- 12.9 pg/ml, P < 0.05) compared with lean (52.4 +/- 4.6 pg/ml), obese (43.9 +/- 3.8 pg/ml), or morbidly obese (45.6 +/- 11.2 pg/ml) subjects. In obese patients, weight loss of 5.4% was associated with a 30% decrease in fasting total PYY plasma levels. In anorectic patients, weight gain had no effect on fasting PYY. PYY(3-36) levels did not differ between lean (96.2 +/- 8.6 pg/ml) and obese (91.5 +/- 6.9 pg/ml) subjects. CONCLUSION: Our findings do not support a role for abnormal circulating PYY in human obesity. We conclude that circulating PYY levels in humans are significantly elevated in anorexia nervosa and, given the controversially discussed anorectic effect of PYY, could theoretically contribute to that syndrome.

Short-term therapy with atorvastatin or fenofibrate does not affect plasma ghrelin, resistin or adiponectin levels in type 2 diabetic patients with mixed hyperlipoproteinaemia.

Lipid-lowering therapy is associated with reduced cardiovascular risk. The aim of the present study was to investigate whether lipid-lowering therapy might be associated with changes in the concentrations of metabolically important hormone concentrations. We performed a randomised cross-over open-label trial with atorvastatin (10 mg/day) and fenofibrate (200 mg/day), each for 6 weeks separated by a 6-week washout period in 13 patients (5 men, 8 women, age 60.0+/-6.8 years, body mass index 30.0+/-3.0 kg/m2) with type 2 diabetes mellitus and mixed hyperlipoproteinaemia. Plasma ghrelin (RIA, Phoenix Pharmaceuticals, Mountain View, CA, USA), adiponectin (ELISA, Biovendor, Heidelberg, Germany) as well as resistin (ELISA, Linco Research, St. Charles, MO, USA) concentrations were measured before and after atorvastatin as well as before and after fenofibrate. Ghrelin (462+/-84 pg/ml before vs. 464+/-102 pg/ml after atorvastatin, n.s.; 454+/-85 pg/ml before vs. 529+/-266 pg/ml after fenofibrate, n.s.), resistin (24.4+/-7.4 pg/ml before vs. 23.7+/-9.1 pg/ml after atorvastatin, n.s.; 23.4+/-8.2 pg/ml before vs. 19.9+/-5.5 pg/ml after fenofibrate, n.s.), adiponectin (10.89+/-5.33 pg/ml before vs. 12.41+/-5.75 pg/ml after atorvastatin, n.s.; 12.58+/-9.87 pg/ml before vs. 10.27+/-5.23 pg/ml after fenofibrate, n.s.) and insulin levels did not change significantly during lipid-lowering therapy. In patients with type 2 diabetes and mixed hyperlipoproteinaemia, short-term atorvastatin as well as fenofibrate therapy had no significant effects on adiponectin, ghrelin or resistin levels.

Glucagon suppression of ghrelin secretion is exerted at hypothalamus-pituitary level.

CONTEXT: The mechanisms underlying the well-known glucagon-induced satiety effect are unclear. Recently, we showed that glucagon induces a remarkable decrease in the orexigenic hormone ghrelin that might be responsible for this effect. OBJECTIVE: The objective of this study was to evaluate the putative role of the hypothalamic pituitary axis in glucagon's suppressive effect on ghrelin secretion. DESIGN, SUBJECTS, AND METHODS: Prospectively, we studied the endocrine and metabolic responses to im glucagon administration in 22 patients (16 males; age, 21-68 yr; body mass index, 28.1 +/- 1.1 kg/m(2)) with a known hypothalamic-pituitary lesion and at least one pituitary hormone deficiency. Control experiments were performed in 27 healthy subjects (15 males; age, 19-65 yr; body mass index, 25.5 +/- 0.9 kg/m(2)). RESULTS: The suppression of ghrelin by glucagon measured as area under the curve(240 min) was significantly greater in controls when compared with patients (P < 0.01). Although there was a significant decrease in ghrelin in controls (P < 0.001), ghrelin was almost unchanged in patients (P = 0.359). Changes in glucagon, glucose, and insulin levels were comparable between both groups. CONCLUSIONS: We show that the hypothalamic-pituitary axis plays an essential role in the suppression of ghrelin induced by im glucagon administration. Glucagon significantly decreases ghrelin levels in healthy subjects. However, in the absence of an intact hypothalamic-pituitary axis, this effect was abolished. The mechanisms responsible for our observation are unlikely to include changes in glucose or insulin levels.