Search

Background: The increasing prevalence of obesity represents a significant and growing challenge in orthopaedic surgery. This is particularly true for patients with morbid obesity, who have a significantly increased risk of postoperative complications. The newer incretin-based therapies (such as semaglutide and tirzepatide), these so-called "weight loss injections", offer promising potential for preoperative weight reduction and minimisation of peri- and postoperative complications., Study Situation: However, the evidence regarding their influence on postoperative outcomes is inconsistent. Retrospective studies suggest that rapid weight loss immediately prior to orthopaedic surgery may increase the risk of complications, including septic shock and revision surgery. Meta-analyses, on the other hand, indicate potential protective effects in surgical outcomes with prior long-term weight reduction., Conclusion: There are currently no sufficiently qualitative studies on the safety and efficacy of these new drugs in the orthopaedic surgery sector. An individualised and multidisciplinary approach, therefore, remains relevant in order to achieve an optimal surgical outcome for the individual patient., Competing Interests: Einhaltung ethischer Richtlinien. Interessenkonflikt: S. Al Basri und W.K. Fenske geben an, dass kein Interessenkonflikt besteht. Für diesen Beitrag wurden von den Autor/-innen keine Studien an Menschen oder Tieren durchgeführt. Für die aufgeführten Studien gelten die jeweils dort angegebenen ethischen Richtlinien., (© 2025. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background & Aims: Survodutide is a glucagon/glucagon-like peptide-1 receptor dual agonist in development for the treatment of metabolic dysfunction-associated steatohepatitis (MASH). We investigated the pharmacokinetic and safety profile of survodutide in people with cirrhosis., Methods: This multinational, non-randomized, open-label, phase I clinical trial initially evaluated a single subcutaneous dose of survodutide 0.3 mg in people with Child-Pugh class A, B or C cirrhosis and healthy individuals with or without overweight/obesity matched for age, sex, and weight; the primary endpoints were the area under the plasma concentration-time curve from 0 to infinity (AUC 0-∞ ) and maximal plasma concentration (C max ). Subsequently, people with overweight/obesity with or without cirrhosis (Child-Pugh class A or B) received once-weekly subcutaneous doses escalated from 0.3 mg to 6.0 mg over 24 weeks then maintained for 4 weeks; the primary endpoint was drug-related treatment-emergent adverse events, with MASH/cirrhosis-related endpoints explored., Results: In the single-dose cohorts (n = 41), mean AUC 0-∞ and C max were similar in those with cirrhosis compared with healthy individuals (90% CIs for adjusted geometric mean ratios spanned 1). Drug-related adverse events occurred in 25.0% of healthy individuals and ≤25.0% of those with cirrhosis after single doses, and 82.4% and 87.5%, respectively, of the multiple-dose cohorts (n = 41) over 28 weeks. Liver fat content, liver stiffness, liver volume, body weight, and other hepatic and metabolic disease markers were generally reduced after 28 weeks of survodutide treatment., Conclusions: Survodutide is generally tolerable in people with compensated or decompensated cirrhosis, does not require pharmacokinetic-related dose adjustment, and may improve liver-related non-invasive tests, supporting its investigation for MASH-related cirrhosis., Impact and Implications: Survodutide is a glucagon receptor/glucagon-like peptide-1 receptor dual agonist in development for treatment of metabolic dysfunction-associated steatohepatitis (MASH), which causes cirrhosis in ∼20% of cases. This trial delineates the pharmacokinetic and safety profile of survodutide in people with compensated or decompensated cirrhosis, and revealed associated reductions in liver fat content, markers of liver fibrosis and body weight. These findings have potential relevance for people with MASH-including those with decompensated cirrhosis, who are usually excluded from clinical trials of investigational drugs. Based on this study, further investigation of survodutide for MASH-related cirrhosis is warranted., Gov Identifier: NCT05296733., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Datasets consist of measurement data and metadata. Metadata provides context, essential for understanding and (re-)using data. Various metadata standards exist for different methods, systems and contexts. However, relevant information resides at differing stages across the data-lifecycle. Often, this information is defined and standardized only at publication stage, which can lead to data loss and workload increase. In this study, we developed Metadatasheet, a metadata standard based on interviews with members of two biomedical consortia and systematic screening of data repositories. It aligns with the data-lifecycle allowing synchronous metadata recording within Microsoft Excel, a widespread data recording software. Additionally, we provide an implementation, the Metadata Workbook, that offers user-friendly features like automation, dynamic adaption, metadata integrity checks, and export options for various metadata standards. By design and due to its extensive documentation, the proposed metadata standard simplifies recording and structuring of metadata for biomedical scientists, promoting practicality and convenience in data management. This framework can accelerate scientific progress by enhancing collaboration and knowledge transfer throughout the intermediate steps of data creation., (© 2024. The Author(s).)

The body of mammals harbors two distinct types of adipose tissue: while cells within the white adipose tissue (WAT) store surplus energy as lipids, brown adipose tissue (BAT) is nowadays recognized as the main tissue for transforming chemical energy into heat. This process, referred to as 'non-shivering thermogenesis', is facilitated by the uncoupling of the electron transport across mitochondrial membranes from ATP production. BAT-dependent thermogenesis acts as a safeguarding mechanism under reduced ambient temperature but also plays a critical role in metabolic and energy homeostasis in health and disease. In this review, we summarize the evolutionary structure, function and regulation of the BAT organ under neuronal and hormonal control and discuss its mutual interaction with the central nervous system. We conclude by conceptualizing how better understanding the multifaceted communicative links between the brain and BAT opens avenues for novel therapeutic approaches to treat obesity and related metabolic disorders.

Objective: Differentiation between central diabetes insipidus (cDI) and primary polydipsia (PP) remains challenging in clinical practice. Although the hypertonic saline infusion test led to high diagnostic accuracy, it is a laborious test requiring close monitoring of plasma sodium levels. As such, we leverage machine learning (ML) to facilitate differential diagnosis of cDI., Design: We analyzed data of 59 patients with cDI and 81 patients with PP from a prospective multicenter study evaluating the hypertonic saline test as new test approach to diagnose cDI. Our primary outcome was the diagnostic accuracy of the ML-based algorithm in differentiating cDI from PP patients., Methods: The data set used included 56 clinical, biochemical, and radiological covariates. We identified a set of five covariates which were crucial for differentiating cDI from PP patients utilizing standard ML methods. We developed ML-based algorithms on the data and validated them with an unseen test data set., Results: Urine osmolality, plasma sodium and glucose, known transsphenoidal surgery, or anterior pituitary deficiencies were selected as input parameters for the basic ML-based algorithm. Testing it on an unseen test data set resulted in a high area under the curve (AUC) score of 0.87. A further improvement of the ML-based algorithm was reached with the addition of MRI characteristics and the results of the hypertonic saline infusion test (AUC: 0.93 and 0.98, respectively)., Conclusion: The developed ML-based algorithm facilitated differentiation between cDI and PP patients with high accuracy even if only clinical information and laboratory data were available, thereby possibly avoiding cumbersome clinical tests in the future.

Injury to the adult mammalian central nervous system induces compensatory plasticity of spared axons-referred to as collateral axon sprouting-that can facilitate neural recovery. The contribution of reactive astrocytes to axon sprouting remains elusive. Here, we sought to investigate the role of axon degeneration-reactive astrocytes in the regulation of collateral axon sprouting that occurs in the mouse spinal cord after unilateral photothrombotic stroke of the primary motor cortex. We identified astrocytic leucine zipper-bearing kinase (LZK) as a positive regulator of astrocyte reactivity to corticospinal axon degeneration. Remarkably, genetic stimulation of astrocyte reactivity, via LZK overexpression in adult astrocytes, enhanced corticospinal axon sprouting. LZK promoted the production of astrocyte-derived ciliary neurotrophic factor (CNTF) that likely enhanced axon growth in mice with astrocytic LZK overexpression after injury. Our finding that LZK-dependent stimulation of astrocyte reactivity promotes corticospinal axon sprouting highlights the potential of engineering astrocytes to support injury-induced axon plasticity for neural repair., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Chen, Ingle, Plautz, Kong, Tang, Ghosh, Romprey, Fenske and Goldberg.)

Background: Bariatric surgery remains the most effective therapy for adiposity reduction and remission of type 2 diabetes. Although different bariatric procedures associate with pronounced shifts in the gut microbiota, their functional role in the regulation of energetic and metabolic benefits achieved with the surgery are not clear., Methods: To evaluate the causal as well as the inherent therapeutic character of the surgery-altered gut microbiome in improved energy and metabolic control in diet-induced obesity, an antibiotic cocktail was used to eliminate the gut microbiota in diet-induced obese rats after gastric bypass surgery, and gastric bypass-shaped gut microbiota was transplanted into obese littermates. Thorough metabolic profiling was combined with omics technologies on samples collected from cecum and plasma to identify adaptions in gut microbiota-host signaling, which control improved energy balance and metabolic profile after surgery., Results: In this study, we first demonstrate that depletion of the gut microbiota largely reversed the beneficial effects of gastric bypass surgery on negative energy balance and improved glucolipid metabolism. Further, we show that the gastric bypass-shaped gut microbiota reduces adiposity in diet-induced obese recipients by re-activating energy expenditure from metabolic active brown adipose tissue. These beneficial effects were linked to improved glucose homeostasis, lipid control, and improved fatty liver disease. Mechanistically, these effects were triggered by modulation of taurine metabolism by the gastric bypass gut microbiota, fostering an increased abundance of intestinal and circulating taurine-conjugated bile acid species. In turn, these bile acids activated gut-restricted FXR and systemic TGR5 signaling to stimulate adaptive thermogenesis., Conclusion: Our results establish the role of the gut microbiome in the weight loss and metabolic success of gastric bypass surgery. We here identify a signaling cascade that entails altered bile acid receptor signaling resulting from a collective, hitherto undescribed change in the metabolic activity of a cluster of bacteria, thereby readjusting energy imbalance and metabolic disease in the obese host. These findings strengthen the rationale for microbiota-targeted strategies to improve and refine current therapies of obesity and metabolic syndrome. Video Abstract Bariatric Surgery (i.e. RYGB) or the repeated fecal microbiota transfer (FMT) from RYGB donors into DIO (diet-induced obesity) animals induces shifts in the intestinal microbiome, an effect that can be impaired by oral application of antibiotics (ABx). Our current study shows that RYGB-dependent alterations in the intestinal microbiome result in an increase in the luminal and systemic pool of Taurine-conjugated Bile acids (TCBAs) by various cellular mechanisms acting in the intestine and the liver. TCBAs induce signaling via two different receptors, farnesoid X receptor (FXR, specifically in the intestines) and the G-protein-coupled bile acid receptor TGR5 (systemically), finally resulting in metabolic improvement and advanced weight management. BSH, bile salt hydrolase; BAT brown adipose tissue., (© 2022. The Author(s).)

Background: Roux-en-Y gastric bypass (RYGB) surgery belongs to the most frequently performed surgical therapeutic strategies against adiposity and its comorbidities. However, outcome is limited in a substantial cohort of patients with inadequate primary weight loss or considerable weight regain. In this study, gut microbiota composition and systemically released metabolites were analyzed in a cohort of extreme weight responders after RYGB., Methods: Patients ( n = 23) were categorized based on excess weight loss (EWL) at a minimum of two years after RYGB in a good responder (EWL 93 ± 4.3%) or a bad responder group (EWL 19.5 ± 13.3%) for evaluation of differences in metabolic outcome, eating behavior and gut microbiota taxonomy and metabolic activity., Results: Mean BMI was 47.2 ± 6.4 kg/m 2 in the bad vs. 26.6 ± 1.2 kg/m 2 in the good responder group ( p = 0.0001). We found no difference in hunger and satiety sensation, in fasting or postprandial gut hormone release, or in gut microbiota composition between both groups. Differences in weight loss did not reflect in metabolic outcome after RYGB. While fecal and circulating metabolite analyses showed higher levels of propionate ( p = 0.0001) in good and valerate ( p = 0.04) in bad responders, respectively, conjugated primary and secondary bile acids were higher in good responders in the fasted ( p = 0.03) and postprandial state (GCA, p = 0.02; GCDCA, p = 0.02; TCA, p = 0.01; TCDCA, p = 0.02; GDCA, p = 0.05; GUDCA, p = 0.04; TLCA, p = 0.04)., Conclusions: Heterogenous weight loss response to RYGB surgery separates from patients' metabolic outcome, and is linked to unique serum metabolite signatures post intervention. These findings suggest that the level of adiposity reduction alone is insufficient to assess the metabolic success of RYGB surgery, and that longitudinal metabolite profiling may eventually help us to identify markers that could predict individual adiposity response to surgery and guide patient selection and counseling.

Objective: To assess the current medical practice in Europe regarding prenatal dexamethasone (Pdex) treatment of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency., Design and Methods: A questionnaire was designed and distributed, including 17 questions collecting quantitative and qualitative data. Thirty-six medical centres from 14 European countries responded and 30 out of 36 centres were reference centres of the European Reference Network on Rare Endocrine Conditions, EndoERN., Results: Pdex treatment is currently provided by 36% of the surveyed centres. The treatment is initiated by different specialties, that is paediatricians, endocrinologists, gynaecologists or geneticists. Regarding the starting point of Pdex, 23% stated to initiate therapy at 4-5 weeks postconception (wpc), 31% at 6 wpc and 46 % as early as pregnancy is confirmed and before 7 wpc at the latest. A dose of 20 µg/kg/day is used. Dose distribution among the centres varies from once to thrice daily. Prenatal diagnostics for treated cases are conducted in 72% of the responding centres. Cases treated per country and year vary between 0.5 and 8.25. Registries for long-term follow-up are only available at 46% of the centres that are using Pdex treatment. National registries are only available in Sweden and France., Conclusions: This study reveals a high international variability and discrepancy in the use of Pdex treatment across Europe. It highlights the importance of a European cooperation initiative for a joint international prospective trial to establish evidence-based guidelines on prenatal diagnostics, treatment and follow-up of pregnancies at risk for CAH.

While the syndrome of inadequate antidiuresis (SIAD) is still the most common cause of hyponatremia in cancer patients, the rise in endocrine immune-related adverse events (irAEs) owing to immune checkpoint inhibitors (ICI) considerably shaped the differential diagnosis of electrolyte disorders in cancer patients. We report here 3 cases of different endocrine irAEs, first manifesting with new-onset hyponatremia under ICI therapy for malignant melanoma: one with primary adrenal insufficiency, one with hypophysitis, and one with autoimmune type 1 diabetes. Early diagnosis of endocrine toxicities can save lives but may be challenging and essentially delayed by subtle or nonspecific clinical presentation and a lack of readily available endocrinological laboratory evaluation in the primary care setting. This exemplary case series demonstrates the broad spectrum of endocrinopathies that physicians should be aware of under ICI therapy and emphasizes new-onset hyponatremia as a possibly early, simple, and low-cost biomarker of irAEs, which may be considered as a red flag in patients receiving checkpoint blockade. As ICI-induced endocrinopathies are still under-represented in clinical practice guidelines, we here propose an updated algorithm for diagnosis of cancer-related hyponatremia, highlighting the important diagnostic steps to be considered before making the diagnosis of SIAD., (© The Author(s) 2022. Published by Oxford University Press on behalf of the Endocrine Society.)

Background: Treatment options for poorly differentiated (PDTC) and anaplastic (ATC) thyroid carcinoma are unsatisfactory and prognosis is generally poor. Lenvatinib (LEN), a multi-tyrosine kinase inhibitor targeting fibroblast growth factor receptors (FGFR) 1-4 is approved for advanced radioiodine refractory thyroid carcinoma, but response to single agent is poor in ATC. Recent reports of combining LEN with PD-1 inhibitor pembrolizumab (PEM) are promising., Materials and Methods: Primary ATC (n=93) and PDTC (n=47) tissue samples diagnosed 1997-2019 at five German tertiary care centers were assessed for PD-L1 expression by immunohistochemistry using Tumor Proportion Score (TPS). FGFR 1-4 mRNA was quantified in 31 ATC and 14 PDTC with RNAscope in-situ hybridization. Normal thyroid tissue (NT) and papillary thyroid carcinoma (PTC) served as controls. Disease specific survival (DSS) was the primary outcome variable., Results: PD-L1 TPS≥50% was observed in 42% of ATC and 26% of PDTC specimens. Mean PD-L1 expression was significantly higher in ATC (TPS 30%) than in PDTC (5%; p<0.01) and NT (0%, p<0.001). 53% of PDTC samples had PD-L1 expression ≤5%. FGFR mRNA expression was generally low in all samples but combined FGFR1-4 expression was significantly higher in PDTC and ATC compared to NT (each p<0.001). No impact of PD-L1 and FGFR 1-4 expression was observed on DSS., Conclusion: High tumoral expression of PD-L1 in a large proportion of ATCs and a subgroup of PDTCs provides a rationale for immune checkpoint inhibition. FGFR expression is low thyroid tumor cells. The clinically observed synergism of PEM with LEN may be caused by immune modulation., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Adam, Kircher, Sbiera, Koehler, Berg, Knösel, Sandner, Fenske, Bläker, Smaxwil, Zielke, Sipos, Allelein, Schott, Dierks, Spitzweg, Fassnacht and Kroiss.)

Objective: Hypothalamic inflammation and endoplasmic reticulum (ER) stress are extensively linked to leptin resistance and overnutrition-related diseases. Surgical intervention remains the most efficient long-term weight-loss strategy for morbid obesity, but mechanisms underlying sustained feeding suppression remain largely elusive. This study investigated whether Roux-en-Y gastric bypass (RYGB) interacts with obesity-associated hypothalamic inflammation to restore central leptin signaling as a mechanistic account for post-operative appetite suppression., Methods: RYGB or sham surgery was performed in high-fat diet-induced obese Wistar rats. Sham-operated rats were fed ad libitum or by weight matching to RYGB via calorie restriction (CR) before hypothalamic leptin signaling, microglia reactivity, and the inflammatory pathways were examined to be under the control of gut microbiota-derived circulating signaling., Results: RYGB, other than CR-induced adiposity reduction, ameliorates hypothalamic gliosis, inflammatory signaling, and ER stress, which are linked to enhanced hypothalamic leptin signaling and responsiveness. Mechanistically, we demonstrate that RYGB interferes with hypothalamic ER stress and toll-like receptor 4 (TLR4) signaling to restore the anorexigenic action of leptin, which most likely results from modulation of a circulating factor derived from the altered gut microbial environment upon RYGB surgery., Conclusions: Our data demonstrate that RYGB interferes with hypothalamic TLR4 signaling to restore the anorexigenic action of leptin, which most likely results from modulation of a circulating factor derived from the post-surgical altered gut microbial environment., (Copyright © 2021 The Authors. Published by Elsevier GmbH.. All rights reserved.)

Objective: Hyperkalemia has been reported upon different hypertonic saline infusion protocols. Since hypertonic saline test has recently been validated for the differential diagnosis of diabetes insipidus (DI), we aimed to investigate the course of plasma potassium during the test., Design: We analyzed data of 90 healthy volunteers and 141 patients with polyuria-polydipsia syndrome (PPS) from two prospective studies evaluating the hypertonic saline test. Our primary outcome was the incidence rate of hypertonic saline-induced hyperkalemia > 5 mmol/L., Methods: Participants received a 250 mL bolus of 3% NaCl solution, followed by 0.15 mL/min/kg body weight continuously infused targeting a plasma sodium level of 150 mmol/L. Blood samples and clinical data were collected every 30 min., Results: Of the 231 participants, 16% (n = 37/231) developed hyperkalemia. The incidence of hyperkalemia was higher in healthy volunteers and in patients with primary polydipsia (25.6% (n = 23/90) and 9.9% (n = 14/141), respectively), and only occurred in 3.4% (n = 2/59) of patients with diabetes insipidus. Hyperkalemia developed mostly at or after 90-min test duration (81.1%, n => 30/37). Predictors of hyperkalemia (OR (95% CI)) were male sex (2.9 (1.2-7.4), P => 0.02), a plasma potassium at baseline > 3.9 mmol/L (5.2 (1.8-17.3), P => 0.004), normonatremia at 30-min test duration (3.2 (1.2-9.5), P => 0.03), and an increase in potassium levels already at 30-min test duration as compared to baseline (4.5 (1.7-12.3), P => 0.003). Hyperkalemia was transient and resolved spontaneously in all cases., Conclusion: The hypertonic saline test can lead to hyperkalemia, especially in patients with primary polydipsia who experience a longer test duration. Monitoring potassium levels in these patients is recommended.

Chronic hexavalent chromium [Cr(VI)] exposure causes lung cancer and other types of cancer; however, the mechanism of Cr(VI) carcinogenesis remains to be clearly defined. Our recent study showed that chronic Cr(VI) exposure upregulates the proto oncogene c-Myc expression, which contributes significantly to Cr(VI)-induced cell transformation, cancer stem cell (CSC)-like property and tumorigenesis. c-Myc is a master regulator of cancer cell abnormal metabolism and accumulating evidence suggests that metabolism dysregulation plays an important role in both cancer development and progression. However, little is known about the role of metabolism dysregulation in Cr(VI) carcinogenesis. This study was performed to investigate the potential role and mechanism of metabolism dysregulation in Cr(VI) carcinogenesis. It was found that Cr(VI)-transformed cells display glycolytic shift, which depends on the upregulation of c-Myc. The glycolytic shift in Cr(VI)-transformed cells led to increased production of acetyl coenzyme A (acetyl-CoA) and elevation of histone acetylation. This, in turn, upregulated the expression of an acetyl-CoA producing key enzyme ATP citrate lyase and c-Myc, forming a positive feedback loop between the upregulation of c-Myc expression, glycolytic shift and increased histone acetylation. It was further determined that glucose depletion not only reverses the glycolytic shift in Cr(VI)-transformed cells, but also significantly reduces their growth, CSC-like property and tumorigenicity. These findings indicate that glycolytic shift plays an important role in maintaining malignant phenotypes of Cr(VI)-transformed cells, suggesting that metabolism dysregulation is critically involved in Cr(VI) carcinogenesis., (© The Author(s) 2020. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) has become state of the art for the quantitative analysis of steroid hormones. Although method comparisons show that aldosterone measurement using LC-MS/MS yields considerably lower levels than immunoassays (IAs), method-specific cutoff values for primary aldosteronism (PA) are largely missing. Objective of this study was to analyze the diagnostic accuracy of proposed LC-MS/MS-specific cutoff values for the saline infusion test (SIT)., Design and Methods: From 2016 to 2019, 104 consecutive patients suspected of PA underwent the SIT and captopril challenge test in the tertiary medical center at the University Hospital of Leipzig, Germany. Patients with positive case confirmation underwent adrenal imaging and adrenal venous sampling for subtype classification., Results: Overall, proposed assay-specific PACLC-MS/MS cutoff values for the SIT achieved higher diagnostic accuracy than established PACIA values with a sensitivity and specificity of 87.5% (95% CI: 71.0-96.5) and 97% (95% CI: 89.6-99.6) for a cutoff of 120 pmol/L and 93.8% (95% CI: 79.2-99.2) and 92.5% (95% CI: 83.4-97.5) for a cutoff of 94 pmol/L. The most accurate post-SIT PACLC-MS/MS cutoff value in this study was 83 pmol/L, yielding a sensitivity and specificity of 96.9% (95% CI: 83.8-99.9) and 92.5% (95% CI: 83.4-97.5), respectively., Conclusions: The present data confirm the need for the implication of lower method-specific aldosterone cutoff values for the diagnosis of PA with LC-MS/MS based aldosterone measurement.

Copeptin: Copeptin is secreted in equimolar amount to Arginine Vasopressin (AVP) but can easily be measured with a sandwich immunoassay. Both peptides, copeptin and AVP, show a high correlation. Accordingly, copeptin mirrors the amount of AVP in the circulation and its measurement provides an attractive marker in the differential diagnosis of diabetes insipidus., The Polyuria Polydipsia Syndrome: Diabetes insipidus-either central or nephrogenic-has to be differentiated from primary polydipsia. Differentiation is crucial since wrong treatment can have deleterious consequences. Since many decades, the "gold standard" for differential diagnosis has been the classical water deprivation test, which has several limitations leading to an overall limited diagnostic accuracy. In addition, the test has a long duration of 17 hours and is cumbersome for patients. Clinical signs and symptoms as well as MRI characteristics overlap between patients with diabetes insipidus and primary polydipsia. Direct measurement of AVP upon osmotic stimulation was first shown to overcome these limitations, but failed to enter clinical practice mainly due to technical limitations of the AVP assay., Copeptin as Diagnostic Tool in the Polyuria Polydipsia Syndrome: We have recently shown that copeptin, without prior water deprivation, identifies patients with nephrogenic diabetes insipidus. On the other hand, for the more difficult differentiation between central diabetes insipidus and primary polydipsia, a copeptin level of 4.9 pmol/L stimulated with hypertonic saline infusion differentiates between these two entities with a high diagnostic accuracy, and is superior to the water deprivation test. It is important to note that close sodium monitoring during the hypertonic saline test is a prerequisite., Conclusion: Therefore, we propose that copeptin upon hypertonic saline infusion should become the new standard test in the differential diagnosis of diabetes insipidus.

Osmotic stimulus or stress results in vasopressin release. Animal and human in vitro studies have shown that inflammatory parameters, such as interleukin-8 (IL-8) and tumor necrosis factor-α (TNF-α), increase in parallel in the central nervous system and bronchial, corneal or intestinal epithelial cell lines in response to osmotic stimulus. Whether osmotic stimulus directly causes a systemic inflammatory response in humans is unknown. We therefore investigated the influence of osmotic stimulus on circulatory markers of systemic inflammation in healthy volunteers. In this prospective cohort study, 44 healthy volunteers underwent a standardized test protocol with an osmotic stimulus leading into the hyperosmotic/hypernatremic range (serum sodium ≥150 mmol/L) by hypertonic saline infusion. Copeptin - a marker indicating vasopressin activity - serum sodium and osmolality, plasma IL-8 and TNF-α were measured at baseline and directly after osmotic stimulus. Median (range) serum sodium increased from 141 mmol/L (136, 147) to 151 mmol/L (145, 154) (P < 0.01), serum osmolality increased from 295 mmol/L (281, 306) to 315 mmol/L (304, 325) (P < 0.01). Median (range) copeptin increased from 4.3 pg/L (1.1, 21.4) to 28.8 pg/L (19.9, 43.4) (P < 0.01). Median (range) IL-8 levels showed a trend to decrease from 0.79 pg/mL (0.37, 1.6) to 0.7 pg/mL (0.4, 1.9) (P < 0.09) and TNF-α levels decreased from 0.53 pg/mL (0.11, 1.1) to 0.45 pg/mL (0.12, 0.97) (P < 0.036). Contrary to data obtained in vitro, circulating proinflammatory cytokines tend to or decrease in human plasma after osmotic stimulus. In this study, osmotic stimulus does not increase circulating markers of systemic inflammation.

Diabetes insipidus (DI) is a disorder characterized by excretion of large amounts of hypotonic urine. Central DI results from a deficiency of the hormone arginine vasopressin (AVP) in the pituitary gland or the hypothalamus, whereas nephrogenic DI results from resistance to AVP in the kidneys. Central and nephrogenic DI are usually acquired, but genetic causes must be evaluated, especially if symptoms occur in early childhood. Central or nephrogenic DI must be differentiated from primary polydipsia, which involves excessive intake of large amounts of water despite normal AVP secretion and action. Primary polydipsia is most common in psychiatric patients and health enthusiasts but the polydipsia in a small subgroup of patients seems to be due to an abnormally low thirst threshold, a condition termed dipsogenic DI. Distinguishing between the different types of DI can be challenging and is done either by a water deprivation test or by hypertonic saline stimulation together with copeptin (or AVP) measurement. Furthermore, a detailed medical history, physical examination and imaging studies are needed to ensure an accurate DI diagnosis. Treatment of DI or primary polydipsia depends on the underlying aetiology and differs in central DI, nephrogenic DI and primary polydipsia.

Objective: Adrenal vein sampling (AVS) represents the current diagnostic standard for subtype differentiation in primary aldosteronism (PA). However, AVS has its drawbacks. It is invasive, expensive, requires an experienced interventional radiologist and comes with radiation exposure. However, exact radiation exposure of patients undergoing AVS has never been examined., Design and Methods: We retrospectively analyzed radiation exposure of 656 AVS performed between 1999 and 2017 at four university hospitals. The primary outcomes were dose area product (DAP) and fluoroscopy time (FT). Consecutively the effective dose (ED) was approximately calculated., Results: Median DAP was found to be 32.5 Gy*cm2 (0.3–3181) and FT 18 min (0.3–184). The calculated ED was 6.4 mSv (0.1–636). Remarkably, values between participating centers highly varied: Median DAP ranged from 16 to 147 Gy*cm2, FT from 16 to 27 min, and ED from 3.2 to 29 mSv. As main reason for this variation, differences regarding AVS protocols between centers could be identified, such as number of sampling locations, frames per second and the use of digital subtraction angiographies., Conclusions: This first systematic assessment of radiation exposure in AVS not only shows fairly high values for patients, but also states notable differences among the centers. Thus, we not only recommend taking into account the risk of radiation exposure, when referring patients to undergo AVS, but also to establish improved standard operating procedures to prevent unnecessary radiation exposure., (© 2018 The authors)

Context: Copeptin is the C-terminal fragment of the arginine vasopressin (AVP) prohormone whose measurement is more robust than that of AVP. Similar release and clearance characteristics have been suggested promoting copeptin as a surrogate marker., Objective: To characterize the physiology of osmotically regulated copeptin release and its half-life in direct comparison with plasma AVP., Design: Ninety-one healthy volunteers underwent a standardized three-phase test protocol including (1) osmotic stimulation into the hypertonic range by hypertonic-saline infusion followed by osmotic suppression via (2) oral water load and (3) subsequent glucose infusion. Plasma copeptin, AVP, serum sodium, and osmolality levels were measured in regular intervals., Results: In phase 1, an increase in median osmotic pressure [289 (286; 291) to 311 (309; 314) mOsm/kg H2O] caused similar release kinetics of plasma copeptin [4 (3.1; 6) to 29.3 (18.6; 48.2) pmol/L] and AVP [1 (0.7; 1.6) to 10.3 (6.8; 18.8) pg/mL]. Subsequent osmotic suppression to 298 (295; 301) mOsm/kg at the end of phase 3 revealed markedly different decay kinetics between both peptides-an estimated initial half-life of copeptin being approximately 2 times longer than that of AVP (26 vs 12 minutes)., Conclusion: Copeptin is released in equimolar amounts with AVP in response to osmotic stimulation, suggesting its high potential as an AVP surrogate for differentiation of osmotic disorders. Furthermore, we here describe the decay kinetics of copeptin in response to osmotic depression enabling to identify a half-life for copeptin in direct comparison with AVP., (Copyright © 2017 Endocrine Society)

18 F-FDG PET imaging is routinely used to investigate brown adipose tissue (BAT) thermogenesis, which requires mitochondrial uncoupling protein 1 (UCP1). It remains uncertain, however, whether BAT 18 F-FDG uptake is a reliable surrogate measure of UCP1-mediated heat production. Methods: UCP1 knockout (KO) and wild-type (WT) mice housed at thermoneutrality were treated with the selective β3 adrenergic receptor agonist CL 316, 243 and underwent metabolic cage, infrared thermal imaging and 18 F-FDG PET/MRI experiments. Primary brown adipocytes were additionally examined for their bioenergetics by extracellular flux analysis as well as their uptake of 2-deoxy- 3 H-glucose. Results: In response to CL 316, 243 treatments, oxygen consumption, and BAT thermogenesis were diminished in UCP1 KO mice, but BAT 18 F-FDG uptake was fully retained. Isolated UCP1 KO brown adipocytes exhibited defective induction of uncoupled respiration whereas their glycolytic flux and 2-deoxy- 3 H-glucose uptake rates were largely unaffected. Conclusion: Adrenergic stimulation can increase BAT 18 F-FDG uptake independently of UCP1 thermogenic function., (© 2017 by the Society of Nuclear Medicine and Molecular Imaging.)

Purpose: The brain noradrenaline (NA) system plays an important role in the central nervous control of energy balance and is thus implicated in the pathogenesis of obesity. The specific processes modulated by this neurotransmitter which lead to obesity and overeating are still a matter of debate., Methods: We tested the hypothesis that in vivo NA transporter (NAT) availability is changed in obesity by using positron emission tomography (PET) and S,S-[ 11 C]O-methylreboxetine (MRB) in twenty subjects comprising ten highly obese (body mass index BMI > 35 kg/m 2 ), metabolically healthy, non-depressed individuals and ten non-obese (BMI < 30 kg/m 2 ) healthy controls., Results: Overall, we found no significant differences in binding potential (BP ND ) values between obese and non-obese individuals in the investigated brain regions, including the NAT-rich thalamus (0.40 ± 0.14 vs. 0.41 ± 0.18; p = 0.84) though additional discriminant analysis correctly identified individual group affiliation based on regional BP ND in all but one (control) case. Furthermore, inter-regional correlation analyses indicated different BP ND patterns between both groups but this did not survive testing for multiple comparions., Conclusions: Our data do not find an overall involvement of NAT changes in human obesity. However, preliminary secondary findings of distinct regional and associative patterns warrant further investigation.

Bariatric surgery remains the single most effective long-term treatment modality for morbid obesity, achieved mainly by lowering caloric intake through as yet ill-defined mechanisms. Here we show in rats that Roux-en-Y gastric bypass (RYGB)-like rerouting of ingested fat mobilizes lower small intestine production of the fat-satiety molecule oleoylethanolamide (OEA). This was associated with vagus nerve-driven increases in dorsal striatal dopamine release. We also demonstrate that RYGB upregulates striatal dopamine 1 receptor (D1R) expression specifically under high-fat diet feeding conditions. Mechanistically, interfering with local OEA, vagal, and dorsal striatal D1R signaling negated the beneficial effects of RYGB on fat intake and preferences. These findings delineate a molecular/systems pathway through which bariatric surgery improves feeding behavior and may aid in the development of novel weight loss strategies that similarly modify brain reward circuits compromised in obesity., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Brain μ-opioid receptors (MORs) stimulate high-fat (HF) feeding and have been implicated in the distinct long term outcomes on body weight of bariatric surgery and dieting. Whether alterations in fat appetite specifically following these disparate weight loss interventions relate to changes in brain MOR signaling is unknown. To address this issue, diet-induced obese male rats underwent either Roux-en-Y gastric bypass (RYGB) or sham surgeries. Postoperatively, animals were placed on a two-choice diet consisting of low-fat (LF) and HF food and sham-operated rats were further split into ad libitum fed (Sham-LF/HF) and body weight-matched (Sham-BWM) to RYGB groups. An additional set of sham-operated rats always only on a LF diet (Sham-LF) served as lean controls, making four experimental groups in total. Corresponding to a stage of weight loss maintenance for RYGB rats, two-bottle fat preference tests in conjunction with small-animal positron emission tomography (PET) imaging studies with the selective MOR radioligand [ 11 C]carfentanil were performed. Brains were subsequently collected and MOR protein levels in the hypothalamus, striatum, prefrontal cortex and orbitofrontal cortex were analyzed by Western Blot. We found that only the RYGB group presented with intervention-specific changes: having markedly suppressed intake and preference for high concentration fat emulsions, a widespread reduction in [ 11 C]carfentanil binding potential (reflecting MOR availability) in various brain regions, and a downregulation of striatal and prefrontal MOR protein levels compared to the remaining groups. These findings suggest that the suppressed fat appetite caused by RYGB surgery is due to reduced brain MOR signaling, which may contribute to sustained weight loss unlike the case for dieting.

The marked (18)F-flurodeoxyglucose uptake by brown adipose tissue (BAT) enabled its identification in human positron emission tomography imaging studies. In this Perspective, we discuss how glucose extraction by BAT and beige adipose tissue (BeAT) sufficiently impacts on glycemic control. We then present a unique overview of the central circuits modulated by gluco-regulatory hormones, temperature, and glucose itself, which converge on sympathetic preganglionic neurons and whose activation syphon circulating glucose into BAT/BeAT. Targeted stimulation of the sympathetic nervous system at specific nodes to selectively recruit BAT/BeAT may represent a safe and effective means of treating diabetes., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Phosphodiesterase type 10A (PDE10A) is highly enriched in striatum and is under evaluation as a drug target for several psychiatric/neurodegenerative diseases. Preclinical studies implicate PDE10A in the regulation of energy homeostasis, but the mechanisms remain unclear. By utilizing small-animal PET/MRI and the novel radioligand [(18)F]-AQ28A, we found marked levels of PDE10A in interscapular brown adipose tissue (BAT) of mice. Pharmacological inactivation of PDE10A with the highly selective inhibitor MP-10 recruited BAT and potentiated thermogenesis in vivo In diet-induced obese mice, chronic administration of MP-10 caused weight loss associated with increased energy expenditure, browning of white adipose tissue, and improved insulin sensitivity. Analysis of human PET data further revealed marked levels of PDE10A in the supraclavicular region where brown/beige adipocytes are clustered in adults. Finally, the inhibition of PDE10A with MP-10 stimulated thermogenic gene expression in human brown adipocytes and induced browning of human white adipocytes. Collectively, our findings highlight a novel thermoregulatory role for PDE10A in mouse and human adipocytes and promote PDE10A inhibitors as promising candidates for the treatment of obesity and diabetes., (© 2016 The Authors. Published under the terms of the CC BY 4.0 license.)

Purpose: The role of the central serotonin (5-hydroxytryptamine, 5-HT) system in feeding has been extensively studied in animals with the 5-HT family of transporters (5-HTT) being identified as key molecules in the regulation of satiety and body weight. Aberrant 5-HT transmission has been implicated in the pathogenesis of human obesity by in vivo positron emission tomography (PET) and single-photon emission computed tomography (SPECT) imaging techniques. However, results obtained thus far from studies of central 5-HTT availability have been inconsistent, which is thought to be brought about mainly by the low number of individuals with a high body mass index (BMI) previously used. The aim of this study was therefore to assess 5-HTT availability in the brains of highly obese otherwise healthy individuals compared with non-obese healthy controls., Methods: We performed PET using the 5-HTT selective radiotracer [(11)C] DASB on 30 highly obese (BMI range between 35 and 55 kg/m(2)) and 15 age- and sex-matched non-obese volunteers (BMI range between 19 and 27 kg/m(2)) in a cross-sectional study design. The 5-HTT binding potential (BPND) was used as the outcome parameter., Results: On a group level, there was no significant difference in 5-HTT BPND in various cortical and subcortical regions in individuals with the highest BMI compared with non-obese controls, while statistical models showed minor effects of age, sex, and the degree of depression on 5-HTT BPND., Conclusion: The overall finding of a lack of significantly altered 5-HTT availability together with its high variance in obese individuals justifies the investigation of individual behavioral responses to external and internal cues which may further define distinct phenotypes and subgroups in human obesity.

Alterations in the dopaminergic system have been implicated in both animal and human obesity. However, to date, a comprehensive model on the nature and functional relevance of this relationship is missing. In particular, human data remain equivocal in that seemingly inconsistent reports exist of positive, negative or even no relationships between dopamine D2/D3 receptor availability in the striatum and measures of obesity. Further, data on receptor availability have been commonly interpreted as reflecting receptor density, despite the possibility of an alternative interpretation, namely alterations in the basal levels of endogenous dopaminergic tone. Here, we provide a unifying framework that is able to explain the seemingly contradictory findings and offer an alternative and novel perspective on existing data. In particular, we suggest (i) a quadratic relationship between alterations in the dopaminergic system and degree of obesity, and (ii) that the observed alterations are driven by shifts in the balance between general dopaminergic tone and phasic dopaminergic signalling. The proposed model consistently integrates human data on molecular and behavioural characteristics of overweight and obesity. Further, the model provides a mechanistic framework accounting not only for the consistent observation of altered (food) reward-responsivity but also for the differences in reinforcement learning, decision-making behaviour and cognitive performance associated with measures of obesity., (© 2015 World Obesity.)

Purpose: To investigate the incidence of hyponatremia and its relationship to plasma copeptin, a surrogate marker for arginine vasopressin (AVP) during 28 days of high-volume rowing training., Methods: Thirty rowers from the German junior national team (21 male) were studied during a training camp. Serum sodium ([Na(+)]), osmolality, and copeptin were measured before the beginning of the camp (day 0), and at days 7, 13, 18, 24, and 28. Daily fluid intake, body weight, urine parameters, and training volume were recorded., Results: Seventy percent of the rowers developed hyponatremia at least once. At day 18, training volume and incidence of hyponatremia (43%) were highest. [Na(+)] decreased from 143 ± 9 mmol·L(-1) (day 0) to 135 ± 5 mmol·L(-1) (day 18, P < .01). Hyponatremia was correlated significantly with weight gain compared with the previous day (P < .01). Copeptin decreased from day 0 to 28 (male: 6.7 ± 2.8 to 3.6 ± 1.7 pmol·L(-1); P < .05; female: 4.8 ± 1.1 to 3.2 ± 1.5 pmol·L(-1); P < .05), being only partially suppressed. Relative fluid intake per body surface area increased from day 7 (male: 2.79 ± 0.78 L·m(-2); female: 2.20 ± 0.70 L·m(-2)) to day 28 (3.88 ± 0.69 L·m(2) and 2.65 ± 0.93 L·m(-2); P < .05). No athlete developed symptomatic hyponatremia., Conclusion: Prolonged high-volume rowing training can lead to a high incidence of hyponatremia. Overdrinking and inadequate suppression of AVP contribute to its development., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: There are numerous reports of increased energy expenditure after Roux-en-Y gastric bypass (RYGB) surgery in humans and rodent models but the underlying mechanisms remain poorly understood. In the present study we assessed at the gene expression level whether RYGB leads to recruitment of brown adipose tissue (BAT) and/or beige adipose tissue (BeAT) as a means of enhanced facultative thermogenesis and increased energy expenditure after surgery., Methods: Diet-induced obese male Wistar rats were randomized into RYGB-operated (n=10), sham-operated ad libitum fed (Sham) (n=7) or sham-operated body weight matched (BWM) to RYGB groups (n=7). At a stage of postoperatively stabilized weight reduction, BAT (interscapular), subcutaneous (inguinal) and visceral (epididymal and perirenal) white adipose tissue (WAT) depots were collected in the fasted state. Expression of thermoregulatory genes (UCP1, CIDEA and PRDM16) in BAT and WAT as well as specific markers of BeAT (Ear2 and TMEM26) in WAT was analyzed using RT-qPCR., Results: Compared to Sham rats, UCP1 mRNA expression in BAT was significantly reduced in BWM, but not in RYGB rats. No differences in mRNA expression were found for thermoregulatory proteins or for markers of BeAT in subcutaneous or visceral WAT depots between RYGB and Sham groups., Conclusion: The compensatory decrease in BAT thermogenic gene expression typically associated with body weight loss is attenuated after RYGB which, as opposed to recruitment of BeAT, may contribute to overall increases in energy expenditure and weight loss maintenance after surgery., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Highly palatable and/or calorically dense foods, such as those rich in fat, engage the striatum to govern and set complex behaviors. Striatal dopamine signaling has been implicated in hedonic feeding and the development of obesity. Dieting and bariatric surgery have markedly different outcomes on weight loss, yet how these interventions affect central homeostatic and food reward processing remains poorly understood. Here, we propose that dieting and gastric bypass produce distinct changes in peripheral factors with known roles in regulating energy homeostasis, resulting in differential modulation of nigrostriatal and mesolimbic dopaminergic reward circuits. Enhancement of intestinal fat metabolism after gastric bypass may also modify striatal dopamine signaling contributing to its unique long-term effects on feeding behavior and body weight in obese individuals., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Brown adipose tissue (BAT) plays an important role in regulating core-body temperature in various species including man. [18F]FDG-PET/CT imaging first revealed the presence of metabolically active BAT depots and that decreased BAT function is associated with various metabolic conditions. Thyroid hormone (TH) in concert with sympathetic nervous system signalling (SNS) stimulates BAT thermogenesis and thyroid disorders result in dysfunctional BAT. Currently, research is focussing not only on BAT regulation but also on browning of white adipose tissue (WAT) to BAT beige adipose tissue (BeAT) in order to develop novel treatments for human obesity and related conditions. While [18F]FDG-PET/CT imaging is continuing to provide valuable insights into BAT and BeAT function in health and disease, there is a pressing need to develop alternative radiotracers that reliably track their activity in vivo. As a result it is expected that preclinical micro PET/CT investigations of BAT and BeAT will gain in prominence. The aim of this short review is to i) describe fundamentals in BAT biology, ii) highlight some of the clinical and preclinical studies performed on humans and rodents with a focus on TH, BAT and PET/CT, and iii) bridge these data with our own studies within the DFG thyroid transact priority program.

Hyponatremia, the most frequent electrolyte disorder, is caused predominantly by the syndrome of inappropriate antidiuresis (SIAD). A comprehensive characterization of SIAD subtypes, defined by type of osmotic dysregulation, is lacking, but may aid in predicting therapeutic success. Here, we analyzed serial measurements of serum osmolality and serum sodium, plasma arginine vasopressin (AVP), and plasma copeptin concentrations from 50 patients with hyponatremia who underwent hypertonic saline infusion. A close correlation between copeptin concentrations and serum osmolality existed in 68 healthy controls, with a mean osmotic threshold±SD of 282±4 mOsM/kg H2O. Furthermore, saline-induced changes in copeptin concentrations correlated with changes in AVP concentrations in controls and patients. With use of copeptin concentration as a surrogate measure of AVP concentration, patients with SIAD could be grouped according to osmoregulatory defect: Ten percent of patients had grossly elevated copeptin concentrations independent of serum osmolality (type A); 14% had copeptin concentrations that increased linearly with rising serum osmolality but had abnormally low osmotic thresholds (type B); 44% had normal copeptin concentrations independent of osmolality (type C), and 12% had suppressed copeptin concentrations independent of osmolality (type D). A novel SIAD subtype discovered in 20% of patients was characterized by a linear decrease in copeptin concentrations with increasing serum osmolality (type E or "barostat reset"). In conclusion, a partial or complete loss of AVP osmoregulation occurs in patients with SIAD. Although the mechanisms underlying osmoregulatory defects in individual patients are presumably diverse, we hypothesize that treatment responses and patient outcomes will vary according to SIAD subtype., (Copyright © 2014 by the American Society of Nephrology.)

Background: Bariatric surgery improves arterial hypertension and renal function; however, the underlying mechanisms and effect of different surgical procedures are unknown. In the present prospective study, we compared the 12-month follow-up results after Roux-en-Y gastric bypass, laparoscopic adjustable gastric banding, and laparoscopic sleeve gastrectomy on weight loss, hypertension, renal function, and inflammatory status., Methods: A total of 34 morbidly obese patients were investigated before, one and 12 months after Roux-en-Y gastric bypass (n = 10), laparoscopic adjustable gastric banding (n = 13), and laparoscopic sleeve gastrectomy (n = 11) for hypertension, kidney function, urinary and serum cytokine levels of macrophage migration inhibitory factor, monocyte chemotactic protein-1, and chemokine ligand-18., Results: At 12 months after surgery, the patients in all 3 treatment arms showed a significant decrease in the mean body mass index, mean arterial pressure, and urinary and serum inflammatory markers (all P < .001). The reduction in urinary and serum cytokine levels correlated directly with body weight loss (P < .05). Patients with impaired renal function at baseline (corresponding to serum cystatin C >.8 mg/L) had a marked improvement in renal function 12 months after surgery (P < .05)., Conclusion: Surgically induced weight loss is associated with a marked decrease in renal and systemic inflammation and arterial hypertension and improvement in renal function in patients with pre-existing renal impairment. These effects appear to be independent of surgical procedure. The improvement in renal inflammation could be 1 of the mechanisms contributing to the beneficial effects of bariatric surgery on arterial blood pressure, proteinuria, and renal function., (Copyright © 2013 American Society for Metabolic and Bariatric Surgery. Published by Elsevier Inc. All rights reserved.)

Patients with a body mass index (BMI) above 35 kg/m(2) with metabolic diseases benefit from Roux-en-Y gastric bypass (RYGB) independently of their final BMI and the amount of body weight lost. However, the weight loss independent metabolic effects induced by RYGB remain less well understood. To elucidate metabolic changes after RYGB, (1)H NMR spectroscopy-based urine metabolic profiles from RYGB (n = 7), ad libitum-fed sham (AL, n = 5), and body-weight-matched sham (BWM, n = 5) operated mice were obtained. Gut morphometry and fecal energy content were analyzed. Food intake and body weight of RYGB mice were significantly reduced (p = 0.001) compared to sham-AL. There was a strong tendency that BWM-shams required less food to maintain the same body weight as RYGB mice (p = 0.05). No differences were found in fecal energy content between the groups, excluding malabsorption in RYGB animals. Unlike RYGB-operated rats, gut hypertrophy was not observed in RYGB-operated mice. Urinary tricarboxylic acid cycle intermediates were higher in the sham groups, suggesting altered mitochondrial metabolism after RYGB surgery. Higher urinary levels of trimethylamine, hippurate and trigonelline in RYGB mice indicate that the RYGB operation caused microbial disturbance. Taken together, we demonstrate for the first time that there are RYGB specific metabolic effects, which are independent of food intake and body weight loss. Increased utilization of TCA cycle intermediates and altered gut microbial-host co-metabolites might indicate increased energy expenditure and microbial changes in the gut, respectively.

Background: Patients show an elevated postprandial satiety gut hormone release after Roux-en-Y Gastric bypass (gastric bypass). The altered gut hormone response appears to have a prominent role in the reduction of appetite and body weight (BW) after gastric bypass. Patients with insufficient BW loss after gastric bypass have an attenuated postprandial gut hormone response in comparison with patients who lost an adequate amount of BW. The effects of additional gut hormone administration after gastric bypass are unknown., Methods: The effects of peripheral administration of peptide YY3-36 (PYY3-36; 300 nmol kg(-1)), glucagon-like peptide-1 (GLP-1) analogue Exendin-4 (20 nmol kg(-1)) and somatostatin analogue octreotide (10 μg kg(-1)) on feeding and BW were evaluated in rats after gastric bypass., Results: Gastric bypass rats weighed (P<0.01) and ate less on postoperative day 5 (P<0.001) and thereafter, whereas postprandial plasma PYY and GLP-1 levels were higher compared with sham-operated controls (P<0.001). Administration of both PYY3-36 and Exendin-4 led to a further decrease in food intake in bypass rats compared with saline treatment (P=0.02 and P<0.0001, respectively). Similar reduction in food intake was observed in sham rats (P=0.02 and P<0.001, respectively). Exendin-4 treatment resulted in a significant BW loss in bypass (P=0.03) and sham rats (P=0.04). Subsequent treatment with octreotide led to an increase in food intake in bypass (P=0.007), but not in sham rats (P=0.87)., Conclusion: Peripheral administration of PYY3-36 and Exendin-4 reduces short-term food intake, whereas octreotide increases short-term food intake in rats after gastric bypass. The endogenous gut hormone response after gastric bypass can thus potentially be further enhanced by additional exogenous therapy with pharmacological doses of gut hormones in patients with insufficient weight loss or weight regain after surgery.

Background: Roux-en-Y gastric bypass surgery (RYGB) is an effective treatment for patients with type 2 diabetes (T2DM). Tight glycaemic control immediately after RYGB for T2DM may improve long-term glycaemic outcomes, but is also associated with a higher risk of hypoglycaemia. We designed a treatment algorithm to achieve optimal glycaemic control in patients with insulin-treated T2DM after RYGB and evaluated its feasibility, safety and efficacy., Methods: Fifty patients following protocol-driven diabetes management were discharged on a fixed amount of metformin and glargine, with the insulin dose adjusted according to a standardised insulin sliding scale aiming for a fasting capillary glucose (FCG) of 5.5-6.9 mmol/L. Glycaemic outcome and remission of diabetes (defined as HbA1c < 6% and FCG levels < 5.6 mmol/L for at least 1 year without hypoglycaemic medication) were compared between patients who received protocol-driven treatment and a similar cohort of 49 patients following standard glycaemic management., Results: At 1 year follow-up, the protocol-driven group showed a greater improvement in glycaemic control than the non-protocol-driven group (HbA1c -3.0 ± 0.2% vs. -1.2 ± 0.1%, P < 0.001; FCG levels -3.4 ± 0.2 vs. -2.0 ± 0.2 mmol/L, P = 0.02) and a higher remission rate from T2DM (50.0% vs. 6.1%, P < 0.001). No symptomatic hypoglycaemia was reported in either group., Conclusions: The protocol-driven management proved to be feasible, safe and effective in achieving targeted glycaemic control in T2DM after RYGB. The next step will be to scrutinise the efficacy of protocol-driven management in a randomised controlled clinical trial.