Update in the CNS response to hypoglycemia

Association between time in range 70-180 mg/dl in early stage and severity with in patients acute pancreatitis

BACKGROUND

It is not well understood whether glucose control in the early stage of acute pancreatitis(AP) is related to outcome. This study aimed to investigate the association between blood glucose time in range (TIR) of 70-180 mg/dL in the first 72 h(h) on admission and the progression of AP.

METHODS

Individuals admitted with AP to the Gastroenterology Department of the Affiliated Changzhou No.2 People's Hospital of Nanjing Medical University between January 2017 and December 2021 were included and retrospectively evaluated. The percentage of TIR between 70 and 180 mg/dL in the first 72 h was calculated. According to the progress of AP at discharge, patients were divided into mild pancreatitis(MAP), and moderately severe acute pancreatitis (MSAP), or severe acute pancreatitis (SAP) groups. We examined the association between TIR or TIR ≥ 70% and AP severity using logistic regression models stratified by a glycosylated hemoglobin (HbA1c) level of 6.5%. Receiver operating characteristic (ROC) curves were generated to assess the ability of the TIR to predict MSAP or SAP.

RESULTS

A total of 298 individuals were included, of whom 35 developed MSAP or SAP. Logistic regression analyses indicated that TIR was independently associated with the incidence of more serious AP (odds ratio [OR] = 0.962, 95% CI = 0.941-0.983, p = 0.001). This association remained significant in individuals with HbA1c levels ≤ 6.5% (OR = 0.928, 95% CI = 0.888-0.969, p = 0.001). A TIR ≥ 70% was independently associated with reduced severity only in people with well-antecedent controls (OR = 0.238; 95% CI = 0.071-0.802; p = 0.020). TIR was not powerful enough to predict the severity of AP in both patients with poor antecedent glucose control (AUC = 0.641) or with HbA1c < 6.5% (AUC = 0.668).

CONCLUSIONS

TIR was independently associated with severity in patients with AP, particularly those with good antecedent glucose control.

Activation of catecholamine neurons in the ventral medulla reduces CCK-induced hypophagia and c-Fos activation in dorsal medullary catecholamine neurons

Catecholamine (CA) neurons within the A1 and C1 cell groups in the ventrolateral medulla (VLM) potently increase food intake when activated by glucose deficit. In contrast, CA neurons in the A2 cell group of the dorsomedial medulla are required for reduction of food intake by cholecystokinin (CCK), a peptide that promotes satiation. Thus dorsal and ventral medullary CA neurons are activated by divergent metabolic conditions and mediate opposing behavioral responses. Acute glucose deficit is a life-threatening condition, and increased feeding is a key response that facilitates survival of this emergency. Thus, during glucose deficit, responses to satiation signals, like CCK, must be suppressed to ensure glucorestoration. Here we test the hypothesis that activation of VLM CA neurons inhibits dorsomedial CA neurons that participate in satiation. We found that glucose deficit produced by the antiglycolytic glucose analog, 2-deoxy-d-glucose, attenuated reduction of food intake by CCK. Moreover, glucose deficit increased c-Fos expression by A1 and C1 neurons while reducing CCK-induced c-Fos expression in A2 neurons. We also selectively activated A1/C1 neurons in TH-Cre⁺ transgenic rats in which A1/C1 neurons were transfected with a Cre-dependent designer receptor exclusively activated by a designer drug (DREADD). Selective activation of A1/C1 neurons using the DREADD agonist, clozapine- N-oxide, attenuated reduction of food intake by CCK and prevented CCK-induced c-Fos expression in A2 CA neurons, even under normoglycemic conditions. Results support the hypothesis that activation of ventral CA neurons attenuates satiety by inhibiting dorsal medullary A2 CA neurons. This mechanism may ensure that satiation does not terminate feeding before restoration of normoglycemia.

Selective Pharmacogenetic Activation of Catecholamine Subgroups in the Ventrolateral Medulla Elicits Key Glucoregulatory Responses

Catecholamine (CA) neurons in the ventrolateral medulla (VLM) contribute importantly to glucoregulation during glucose deficit. However, it is not known which CA neurons elicit different glucoregulatory responses or whether selective activation of CA neurons is sufficient to elicit these responses. Therefore, to selectively activate CA subpopulations, we injected male or female Th-Cre+ transgenic rats with the Cre-dependent DREADD construct, AAV2-DIO-hSyn-hM3D(Gq)-mCherry, at one of four rostrocaudal levels of the VLM: rostral C1 (C1r), middle C1 (C1m), the area of A1 and C1 overlap (A1/C1), and A1. Transfection was highly selective for CA neurons at each site. Systemic injection of the Designer Receptor Exclusively Activated by Designer Drugs (DREADD) receptor agonist, clozapine-N-oxide (CNO), stimulated feeding in rats transfected at C1r, C1m, or A1/C1 but not A1. CNO increased corticosterone secretion in rats transfected at C1m or A1/C1 but not A1. In contrast, CNO did not increase blood glucose or induce c-Fos expression in the spinal cord or adrenal medulla after transfection of any single VLM site but required dual transfection of both C1m and C1r, possibly indicating that CA neurons mediating blood glucose responses are more sparsely distributed in C1r and C1m than those mediating feeding and corticosterone secretion. These results show that selective activation of C1 CA neurons is sufficient to increase feeding, blood glucose levels, and corticosterone secretion and suggest that each of these responses is mediated by CA neurons concentrated at different levels of the C1 cell group.

A Single Bout of High-Intensity Interval Training Reduces Awareness of Subsequent Hypoglycemia in Patients With Type 1 Diabetes

High-intensity interval training (HIIT) has gained increasing popularity in patients with diabetes. HIIT acutely increases plasma lactate levels. This may be important, since the administration of lactate during hypoglycemia suppresses symptoms and counterregulation while preserving cognitive function. We tested the hypothesis that, in the short term, HIIT reduces awareness of hypoglycemia and attenuates hypoglycemia-induced cognitive dysfunction. In a randomized crossover trial, patients with type 1 diabetes and normal awareness of hypoglycemia (NAH), patients with impaired awareness of hypoglycemia (IAH), and healthy participants (n = 10 per group) underwent a hyperinsulinemic-hypoglycemic (2.6 mmol/L) clamp, either after a HIIT session or after seated rest. Compared with rest, HIIT reduced symptoms of hypoglycemia in patients with NAH but not in healthy participants or patients with IAH. HIIT attenuated hypoglycemia-induced cognitive dysfunction, which was mainly driven by changes in the NAH subgroup. HIIT suppressed cortisol and growth hormone responses, but not catecholamine responses to hypoglycemia. The present findings demonstrate that a single HIIT session rapidly reduces awareness of subsequent hypoglycemia in patients with type 1 diabetes and NAH, but does not in patients with IAH, and attenuates hypoglycemia-induced cognitive dysfunction. The role of exercise-induced lactate in mediating these effects, potentially serving as an alternative fuel for the brain, should be further explored.

Whole genome expression profiling associates activation of unfolded protein response with impaired production and release of epinephrine after recurrent hypoglycemia

Recurrent hypoglycemia can occur as a major complication of insulin replacement therapy, limiting the long-term health benefits of intense glycemic control in type 1 and advanced type 2 diabetic patients. It impairs the normal counter-regulatory hormonal and behavioral responses to glucose deprivation, a phenomenon known as hypoglycemia associated autonomic failure (HAAF). The molecular mechanisms leading to defective counter-regulation are not completely understood. We hypothesized that both neuronal (excessive cholinergic signaling between the splanchnic nerve fibers and the adrenal medulla) and humoral factors contribute to the impaired epinephrine production and release in HAAF. To gain further insight into the molecular mechanism(s) mediating the blunted epinephrine responses following recurrent hypoglycemia, we utilized a global gene expression profiling approach. We characterized the transcriptomes during recurrent (defective counter-regulation model) and acute hypoglycemia (normal counter-regulation group) in the adrenal medulla of normal Sprague-Dawley rats. Based on comparison analysis of differentially expressed genes, a set of unique genes that are activated only at specific time points after recurrent hypoglycemia were revealed. A complementary bioinformatics analysis of the functional category, pathway, and integrated network indicated activation of the unfolded protein response. Furthermore, at least three additional pathways/interaction networks altered in the adrenal medulla following recurrent hypoglycemia were identified, which may contribute to the impaired epinephrine secretion in HAAF: greatly increased neuropeptide signaling (proenkephalin, neuropeptide Y, galanin); altered ion homeostasis (Na+, K+, Ca2+) and downregulation of genes involved in Ca2+-dependent exocytosis of secretory vesicles. Given the pleiotropic effects of the unfolded protein response in different organs, involved in maintaining glucose homeostasis, these findings uncover broader general mechanisms that arise following recurrent hypoglycemia which may afford clinicians an opportunity to modulate the magnitude of HAAF syndrome.

Microglial Function during Glucose Deprivation: Inflammatory and Neuropsychiatric Implications

Inflammation is increasingly recognized as a contributor to the pathophysiology of neuropsychiatric disorders, including depression, anxiety disorders and autism, though the factors leading to contextually inappropriate or sustained inflammation in pathological conditions are yet to be elucidated. Microglia, as the key mediators of inflammation in the CNS, serve as likely candidates in initiating pathological inflammation and as an ideal point of therapeutic intervention. Glucose deprivation, as a component of the pathophysiology of ischemia or occurring transiently in diabetes, may serve to modify microglial function contributing to inflammatory injury. To this end, primary microglia were cultured from postnatal rat brain and subject to glucose deprivation in vitro. Microglia were characterized for their proliferation, phagocytic function and secretion of inflammatory factors, and tested for their capacity to respond to a potent inflammatory stimulus. In the absence of glucose, microglia remained capable of proliferation, phagocytosis and inflammatory activation and showed increased release of inflammatory factors after presentation of an inflammatory stimulus. Glucose-deprived microglia demonstrated increased phagocytic activity and decreased accumulation of lipids in lipid droplets over a 48-h timecourse, suggesting they may use scavenged lipids as a key alternate energy source during metabolic stress. In the present manuscript, we present novel findings that glucose deprivation may sensitize microglial release of inflammatory mediators and prime microglial functions for both survival and inflammatory roles, which may contribute to psychiatric comorbidities of ischemia, diabetes and/or metabolic disorder.

Current and future medical treatments for patients with acromegaly

INTRODUCTION

Acromegaly is a relatively rare condition of growth hormone (GH) excess associated with significant morbidity and, when left untreated, high mortality. Therapy for acromegaly is targeted at decreasing GH and insulin-like growth hormone 1 levels, ameliorating patients' symptoms and decreasing any local compressive effects of the pituitary adenoma. The therapeutic options for acromegaly include surgery, medical therapies (such as dopamine agonists, somatostatin receptor ligands and the GH receptor antagonist pegvisomant) and radiotherapy. However, despite all these treatments option, approximately 50% of patients are not adequately controlled.

AREAS COVERED

In this paper, the authors discuss: 1) efficacy and safety of current medical therapy 2) the efficacy and safety of the new multireceptor-targeted somatostatin ligand pasireotide 3) medical treatments currently under clinical investigation (oral octreotide, ITF2984, ATL1103), and 4) preliminary data on the use of new injectable and transdermal/transmucosal formulations of octreotide.

EXPERT OPINION

This expert opinion supports the need for new therapeutic agents and modalities for patients with acromegaly.

Subjects with isolated GH deficiency due to a null GHRHR mutation eat proportionally more, but healthier than controls

The GH/IGF-I axis has important interactions with the alimentary system and with the balance between energy intake (EI) and energy requirement (ER). Reduced EI has been described in adult-onset acquired GH deficiency (GHD). Individuals from the Brazilian Itabaianinha cohort, with isolated GHD (IGHD) due to a homozygous mutation (c.57+1G→A) in the GHRH receptor gene, are an ideal model to study the consequences of lifetime GHD. The purpose of this study is to evaluate EI and ER in this untreated IGHD cohort. Cross-sectional study of 24 adult IGHD patients and 23 controls from the same region, matched for age and gender. Estimated EI (EEI) was evaluated by dietary recall, and estimated ER (EER) by the equation of the Dietary Reference Intakes. Fat mass was assessed by DXA. Both EEI and EER were lower in IGHD than controls. However, when corrected by body weight, EEI was higher in IGHD (p = 0.005). IGHD individuals consume in percentage more proteins (p < 0.0001), less carbohydrates (p = 0.013), and equal amount of lipids in comparison to controls. The higher EEI per body weight suggests a possible increase of orexigenic mechanisms in untreated IGHD individuals, ensuring greater caloric intake, which would have adaptive advantages for small-sized individuals in environments with limited access to food. IGHD individuals seem to have a healthier dietary pattern than CO.

Hypothalamic-Pituitary-Adrenal Axis Programming after Recurrent Hypoglycemia during Development

Permanent brain injury is a complication of recurrent hypoglycemia during development. Recurrent hypoglycemia also has adverse consequences on the neuroendocrine system. Hypoglycemia-associated autonomic failure, characterized by ineffective glucose counterregulation during hypoglycemia, is well described in children and adults on insulin therapy for diabetes mellitus. Whether recurrent hypoglycemia also has a programming effect on the hypothalamus-pituitary-adrenal cortex (HPA) axis has not been well studied. Hypoglycemia is a potent stress that leads to increased glucocorticoid secretion in all age groups, including the perinatal period. Other conditions associated with exposure to excess glucocorticoid in the perinatal period have a programming effect on the HPA axis activity. Limited animal data suggest the possibility of similar programming effect after recurrent hypoglycemia in the postnatal period. The age at exposure to hypoglycemia likely determines the HPA axis response in adulthood. Recurrent hypoglycemia in the early postnatal period likely leads to a hyperresponsive HPA axis, whereas recurrent hypoglycemia in the late postnatal period lead to a hyporesponsive HPA axis in adulthood. The age-specific programming effects may determine the neuroendocrine response during hypoglycemia and other stressful events in individuals with history of recurrent hypoglycemia during development.

X-linked acrogigantism syndrome: clinical profile and therapeutic responses

X-linked acrogigantism (X-LAG) is a new syndrome of pituitary gigantism, caused by microduplications on chromosome Xq26.3, encompassing the gene GPR101, which is highly upregulated in pituitary tumors. We conducted this study to explore the clinical, radiological, and hormonal phenotype and responses to therapy in patients with X-LAG syndrome. The study included 18 patients (13 sporadic) with X-LAG and microduplication of chromosome Xq26.3. All sporadic cases had unique duplications and the inheritance pattern in two families was dominant, with all Xq26.3 duplication carriers being affected. Patients began to grow rapidly as early as 2-3 months of age (median 12 months). At diagnosis (median delay 27 months), patients had a median height and weight standard deviation scores (SDS) of >+3.9 SDS. Apart from the increased overall body size, the children had acromegalic symptoms including acral enlargement and facial coarsening. More than a third of cases had increased appetite. Patients had marked hypersecretion of GH/IGF1 and usually prolactin, due to a pituitary macroadenoma or hyperplasia. Primary neurosurgical control was achieved with extensive anterior pituitary resection, but postoperative hypopituitarism was frequent. Control with somatostatin analogs was not readily achieved despite moderate to high levels of expression of somatostatin receptor subtype-2 in tumor tissue. Postoperative use of adjuvant pegvisomant resulted in control of IGF1 in all five cases where it was employed. X-LAG is a new infant-onset gigantism syndrome that has a severe clinical phenotype leading to challenging disease management.

Hypoglycemia-associated changes in the electroencephalogram in patients with type 1 diabetes and normal hypoglycemia awareness or unawareness

Hypoglycemia is associated with increased activity in the low-frequency bands in the electroencephalogram (EEG). We investigated whether hypoglycemia awareness and unawareness are associated with different hypoglycemia-associated EEG changes in patients with type 1 diabetes. Twenty-four patients participated in the study: 10 with normal hypoglycemia awareness and 14 with hypoglycemia unawareness. The patients were studied at normoglycemia (5-6 mmol/L) and hypoglycemia (2.0-2.5 mmol/L), and during recovery (5-6 mmol/L) by hyperinsulinemic glucose clamp. During each 1-h period, EEG, cognitive function, and hypoglycemia symptom scores were recorded, and the counterregulatory hormonal response was measured. Quantitative EEG analysis showed that the absolute amplitude of the θ band and α-θ band up to doubled during hypoglycemia with no difference between the two groups. In the recovery period, the θ amplitude remained increased. Cognitive function declined equally during hypoglycemia in both groups and during recovery reaction time was still prolonged in a subset of tests. The aware group reported higher hypoglycemia symptom scores and had higher epinephrine and cortisol responses compared with the unaware group. In patients with type 1 diabetes, EEG changes and cognitive performance during hypoglycemia are not affected by awareness status during a single insulin-induced episode with hypoglycemia.

Japanese encephalitis virus nonstructural protein NS5 interacts with mitochondrial trifunctional protein and impairs fatty acid β-oxidation

Infection with Japanese encephalitis virus (JEV) can induce the expression of pro-inflammatory cytokines and cause acute encephalitis in humans. β-oxidation breaks down fatty acids for ATP production in mitochondria, and impaired β-oxidation can induce pro-inflammatory cytokine expression. To address the role of fatty-acid β-oxidation in JEV infection, we measured the oxygen consumption rate of mock- and JEV-infected cells cultured with or without long chain fatty acid (LCFA) palmitate. Cells with JEV infection showed impaired LCFA β-oxidation and increased interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) expression. JEV nonstructural protein 5 (NS5) interacted with hydroxyacyl-CoA dehydrogenase α and β subunits, two components of the mitochondrial trifunctional protein (MTP) involved in LCFA β-oxidation, and NS5 proteins were detected in mitochondria and co-localized with MTP. LCFA β-oxidation was impaired and higher cytokines were induced in cells overexpressing NS5 protein as compared with control cells. Deletion and mutation studies showed that the N-terminus of NS5 was involved in the MTP association, and a single point mutation of NS5 residue 19 from methionine to alanine (NS5-M19A) reduced its binding ability with MTP. The recombinant JEV with NS5-M19A mutation (JEV-NS5-M19A) was less able to block LCFA β-oxidation and induced lower levels of IL-6 and TNF-α than wild-type JEV. Moreover, mice challenged with JEV-NS5-M19A showed less neurovirulence and neuroinvasiveness. We identified a novel function of JEV NS5 in viral pathogenesis by impairing LCFA β-oxidation and inducing cytokine expression by association with MTP.

Real-time effects of insulin-induced hypoglycaemia on hippocampal glucose and oxygen

The hippocampus plays a vital role in learning and memory and is susceptible to damage following hypoglycaemic shock. The effect of an acute administration of insulin on hippocampal function has been described in terms of behavioural deficits but its effect on hippocampal oxygen and glucose is unclear. Glucose oxidase biosensors (detecting glucose) and carbon paste electrodes (detecting oxygen) were implanted into the hippocampus of Sprague Dawley rats. Animals were allowed to recover and real-time recordings were made in order to determine the effects of fasting, insulin administration (15 U/kg; i.p.) and reintroduction of food on hippocampal oxygen and glucose. Fasting caused a significant decrease in hippocampal glucose over the course of 24h. Insulin administration produced a significant decrease in hippocampal glucose along with a significant increase in hippocampal oxygen. Finally, the reintroduction of food resulted in glucose levels significantly increasing along with a transient but significant increase in oxygen levels. The findings presented here suggest that even a single acute period of hypoglycaemia may substantially disrupt hippocampal oxygen and glucose and therefore affect hippocampal function.

Application of a glycaemic control optimization programme in patients with stress hyperglycaemia

BACKGROUND

Stress-induced hyperglycaemia (SHG) can be observed in as high as 75% of critically ill patients, which can induce severe complications or adverse events. However, conventional intensive insulin therapy (CIIT) tends to induce hypoglycaemia and glucose variability.

AIMS

This study investigated the clinical effects of a blood glycaemic control optimization programme (BGCOP) in patients with stress hyperglycaemia post hepatobiliary or pancreatic surgery.

DESIGN

This study is a randomized, controlled, prospective clinical observation.

METHODS

Eighty-six patients with postoperative SHG were randomly divided into a control and experimental groups. Participants in the control group underwent CIIT, while participants in the experimental group underwent blood glycaemic control optimization programme (BGCOP). A range of 7·8-10·0 mmol/L was designated as the target range for effective control of blood sugar. The validity index, adverse events and complications were compared between two groups.

RESULTS

Compared to participants treated with CIIT, participants treated with BGCOP reached the target range of blood sugar levels more quickly (p = 0·000). The high glycaemic index (p = 0·000), incidence of hypoglycaemia (p = 0·011), and other adverse events as well as the incidence of abdominal infection (p = 0·026), incision infection (p = 0·044), and lung infection (p = 0·047) were significantly lower in participants who underwent the BGCOP than in patients treated with CIIT.

CONCLUSION

BGCOP can more effectively control blood sugar levels compared with CIIT in patients with SHG after hepatobiliary or pancreatic surgery.

RELEVANCE TO CLINICAL PRACTICE

This study provides a direction for blood glycaemic control in patients with stress hyperglycaemia post hepatobiliary or pancreatic surgery.

Efficacy and safety of insulin degludec given as part of basal-bolus treatment with mealtime insulin aspart in type 1 diabetes: a 26-week randomized, open-label, treat-to-target non-inferiority trial

AIMS

The efficacy and safety of insulin degludec (IDeg) was compared with insulin detemir (IDet), both administered once daily (OD) as basal treatment in participants with type 1 diabetes mellitus (T1DM). The primary outcome was non-inferiority of IDeg to IDet in glycated haemoglobin (HbA1c) reduction after 26 weeks.

METHODS

This multinational, 26-week, controlled, open-label, parallel-group trial randomized adults with T1DM to IDeg or IDet as OD basal insulin treatment combined with mealtime bolus insulin aspart (IAsp). Participants with T1DM treated with any basal-bolus insulin regimen for ≥ 12 months prior to the trial, a mean HbA1c ≤ 10.0% (85.8 mmol/mol) and body mass index (BMI) ≤ 35.0 kg/m(2) at screening participated in the trial (IDeg: N = 302; IDet: N = 153).

RESULTS

After 26 weeks, HbA1c decreased 0.73% (8.0 mmol/mol) (IDeg) and 0.65% (7.1 mmol/mol) (IDet) [estimated treatment difference (ETD) IDeg-IDet: -0.09% (-0.23; 0.05)95% CI (-10.0 mmol/mol [-2.6; 0.6]95% CI ); confirming non-inferiority]. Mean fasting plasma glucose improved in both groups, and was lower with IDeg than IDet [ETD IDeg-IDet: -1.66 mmol/l (-2.37; -0.95)95% CI , p < 0.0001]. The rate of confirmed hypoglycaemia was similar with IDeg and IDet [45.83 vs. 45.69 episodes per patient-year of exposure (PYE); estimated rate ratio (RR) IDeg/IDet: 0.98 (0.80; 1.20)95% CI , p = 0.86]. The rate of nocturnal confirmed hypoglycaemia was lower with IDeg than IDet [4.14 vs. 5.93 episodes per PYE; RR IDeg/IDet: 0.66 (0.49; 0.88)95% CI , p = 0.0049]. Adverse event profiles were similar between groups.

CONCLUSION

IDeg administered OD in basal-bolus therapy effectively improved long-term glycaemic control in participants with T1DM with a lower risk of nocturnal confirmed hypoglycaemia than IDet.

Differential production of reactive oxygen species in distinct brain regions of hypoglycemic mice

Hypoglycemia is a serious complication of insulin therapy in patients suffering from type 1 Diabetes Mellitus. Severe hypoglycemia leading to coma (isoelectricity) induces massive neuronal death in vulnerable brain regions such as the hippocampus, the striatum and the cerebral cortex. It has been suggested that the production of reactive oxygen species (ROS) and oxidative stress is involved in hypoglycemic brain damage, and that ROS generation is stimulated by glucose reintroduction (GR) after the hypoglycemic coma. However, the distribution of ROS in discrete brain regions has not been studied in detail. Using the oxidation sensitive marker dihydroethidium (DHE) we have investigated the distribution of ROS in different regions of the mouse brain during prolonged severe hypoglycemia without isoelectricity, as well as the effect of GR on ROS levels. Results show that ROS generation increases in the hippocampus, the cerebral cortex and the striatum after prolonged severe hypoglycemia before the coma. The hippocampus showed the largest increases in ROS levels. GR further stimulated ROS production in the hippocampus and the striatum while in the cerebral cortex, only the somatosensory and parietal areas were significantly affected by GR. Results suggest that ROS are differentially produced during the hypoglycemic insult and that a different response to GR is present among distinct brain regions.

Sleep and energy intake in early childhood

Background And Objectives:

Shorter sleep is associated with higher weight in children, but little is known about the mechanisms. The aim of this study was to test the hypothesis that shorter sleep was associated with higher energy intake in early childhood.

Methods:

Participants were 1303 families from the Gemini twin birth cohort. Sleep duration was measured using the Brief Infant Sleep Questionnaire when the children were 16 months old. Total energy intake (kcal per day) and grams per day of fat, carbohydrate and protein were derived from 3-day diet diaries completed by parents when children were 21 months old.

Results:

Shorter nighttime sleep was associated with higher total energy intake (P for linear trend=0.005). Children sleeping <10 h consumed around 50 kcal per day more than those sleeping 11–<12 h a night (the optimal sleep duration for children of this age). Differences in energy intake were maintained after adjustment for confounders. As a percentage of total energy intake, there were no significant differences in macronutrient intake by sleep duration. The association between sleep and weight was not significant at this age (P=0.13).

Conclusions:

This study provides the first evidence that shorter nighttime sleep duration has a linear association with higher energy intake early in life. That the effect is observed before emergence of associations between sleep and weight indicates that differences in energy intake may be a mechanism through which sleep influences weight gain.

How do we know if the brain is wired for type 2 diabetes?

It is now widely accepted that the brain makes important contributions to the dysregulated glucose metabolism, altered feeding behaviors, and the obesity often seen in type 2 diabetes (T2D). Although studies focusing on genetic, cellular, and molecular regulatory elements in pancreas, liver, adipose tissue etc provide a good understanding of how these processes relate to T2D, our knowledge of how brain wiring patterns are organized is much less developed. This article discusses animal studies that illustrate the importance of understanding the network organization of those brain regions most closely implicated in T2D. It will describe the brain networks, as well as the methodologies used to explore them. To illustrate some of the gaps in our knowledge, we will discuss the connectional network of the ventromedial nucleus and its adjacent cell groups in the hypothalamus; structures that are widely recognized as key elements in the brain's ability to control glycemia, feeding, and body weight.

Severe hypoglycemia in a juvenile diabetic rat model: presence and severity of seizures are associated with mortality

It is well accepted that insulin-induced hypoglycemia can result in seizures. However, the effects of the seizures, as well as possible treatment strategies, have yet to be elucidated, particularly in juvenile or insulin-dependent diabetes mellitus (IDDM). Here we establish a model of diabetes in young rats, to examine the consequences of severe hypoglycemia in this age group; particularly seizures and mortality. Diabetes was induced in post-weaned 22-day-old Sprague-Dawley rats by streptozotocin (STZ) administered intraperitoneally (IP). Insulin IP (15 U/kg), in rats fasted (14-16 hours), induced hypoglycemia, defined as <3.5 mM blood glucose (BG), in 68% of diabetic (STZ) and 86% of control rats (CON). Seizures occurred in 86% of STZ and all CON rats that reached hypoglycemic levels with mortality only occurring post-seizure. The fasting BG levels were significantly higher in STZ (12.4 ± 1.3 mM) than in CON rodents (6.3 ± 0.3 mM), resulting in earlier onset of hypoglycemia and seizures in the CON group. However, the BG at seizure onset was statistically similar between STZ (1.8 ± 0.2 mM) and CON animals (1.6 ± 0.1 mM) as well as between those that survived (S+S) and those that died (S+M) post-seizure. Despite this, the S+M group underwent a significantly greater number of seizure events than the S+S group. 25% glucose administered at seizure onset and repeated with recurrent seizures was not sufficient to mitigate these continued convulsions. Combining glucose with diazepam and phenytoin significantly decreased post-treatment seizures, but not mortality. Intracranial electroencephalograms (EEGs) were recorded in 10 CON and 9 STZ animals. Predictive EEG changes were not observed in these animals that underwent seizures. Fluorojade staining revealed damaged cells in non-seizing STZ animals and in STZ and CON animals post-seizure. In summary, this model of hypoglycemia and seizures in juvenile diabetic rats provides a paradigm for further study of underlying mechanisms. Our data demonstrate that severe hypoglycemia (<2.0 mM) is a necessary precondition for seizures, and the increased frequency of these seizures is associated with mortality.

Emerging drugs for acromegaly

INTRODUCTION

Acromegaly is a rare disease that severely impacts patients' health all the while, being a slowly progressing illness. In the past decades, advancements in treatment modalities, especially development of new drugs, as well as focused guidelines has improved management of acromegaly. Still, many patients are considered not sufficiently treated and there remains an ongoing need for further development.

AREAS COVERED

This article reviews new medical treatments currently under clinical investigation (such as pasireotide, oral octreotide and somatoprim) and under experimental development (such as octreotide implants, CAM2029 and ATL-1103).

EXPERT OPINION

As it seems unlikely that one single agent may achieve cure in 100% of cases, there is an urgent need for new agents that help patients where current medication fails. Imperatively, this means we have to improve our understanding of the underlying pathogenetic and molecular mechanisms.

An insulinoma presenting with hypochondriac delusions and food refusal

The authors report a case of a 68-year-old man with an unrecognized insulinoma manifesting with neuropsychiatric symptoms. For two years, he presented with unspecified behavior changes, autonomic and neuroglycopenic symptoms, which led him to be misdiagnosed with a neurologic and psychiatric disorder before the insulinoma was recognized. Following neurological alterations in context of hypoglycemia, subsequent to longstanding food refusal, he was admitted in the psychiatric ward. Despite good global response and normal food intake, hypoglycemic episodes were still occurring and led to a careful evaluation which permitted the definitive diagnostic. This case highlights the diagnostic difficulties of medical disorders presenting with clinical features overlapping neurological and psychiatric syndromes. It also reflects the diagnostic difficulties in rare clinical entities, particularly in patients previously followed in psychiatry and underlines the need for a constant dialogue and updating of clinicians.

NMDA receptor blockade by memantine does not prevent adaptation to recurrent hypoglycaemia in healthy men

AIMS

Recurrent hypoglycaemia leads to an attenuation of hypoglycaemic symptoms and hormonal counterregulatory responses. This phenomenon poses a severe problem in the treatment of patients with diabetes mellitus, but the underlying neuroendocrine mechanisms are unclear. On the basis of animal experimental findings, we hypothesized that counterregulatory attenuation represents a basic adaptive learning process relying on synaptic long-term potentiation or depression. If so, attenuation should be prevented by blocking glutamatergic N-methyl-D-aspartate (NMDA) receptors.

METHODS

Sixteen healthy young men participated in two conditions, separated by 4 weeks. Participants received the NMDA antagonist memantine over 5 days (15 mg/day) in one condition and placebo in the other one. After 3 days of drug administration, participants underwent two hypoglycaemic clamps on day 4 and another one on day 5. We assessed blood concentrations of counterregulatory hormones (cortisol, ACTH, epinephrine, norepinephrine, growth hormone and glucagon) as well as subjective symptoms of hypoglycaemia and word-list recall as an indicator of short-term memory.

RESULTS

Counterregulatory responses of all hormones as well as neuroglycopenic and autonomic symptom ratings showed robust attenuation following the third as compared to the first hypoglycaemia (p < 0.05). NMDA receptor antagonization by memantine impaired memory function but did not alter any neuroendocrine measure of counterregulatory attenuation (p > 0.17).

CONCLUSIONS

Attenuation of the endocrine as well as symptomatic counterregulatory response to recurrent hypoglycaemia is not prevented by the NMDA receptor blocker memantine. Our results do not support the view that adaptation to repeated hypoglycaemia relies on NMDA receptor-mediated plastic processes involving long-term potentiation or depression.

The effect of diabetes mellitus on the association between measures of glycaemic control and ICU mortality: a retrospective cohort study

INTRODUCTION

In critical illness, four measures of glycaemic control are associated with ICU mortality: mean glucose concentration, glucose variability, the incidence of hypoglycaemia (≤2.2 mmol/l) or low glucose (2.3 to 4.7 mmol/l). Underlying diabetes mellitus (DM) might affect these associations. Our objective was to study whether the association between these measures of glycaemic control and ICU mortality differs between patients without and with DM and to explore the cutoff value for detrimental low glucose in both cohorts.

METHODS

This retrospective database cohort study included patients admitted between January 2004 and June 2011 to a 24-bed medical/surgical ICU in a teaching hospital. We analysed glucose and outcome data from 10,320 patients: 8,682 without DM and 1,638 with DM. The cohorts were subdivided into quintiles of mean glucose and quartiles of glucose variability. Multivariable regression models were used to examine the independent association between the four measures of glycaemic control and ICU mortality, and for defining the cutoff value for detrimental low glucose.

RESULTS

Regarding mean glucose, a U-shaped relation was observed in the non-DM cohort with an increased ICU mortality in the lowest and highest glucose quintiles (odds ratio=1.4 and 1.8, P<0.001). No clear pattern was found in the DM cohort. Glucose variability was related to ICU mortality only in the non-DM cohort, with highest ICU mortality in the upper variability quartile (odds ratio=1.7, P<0.001). Hypoglycaemia was associated with ICU mortality in both cohorts (odds ratio non-DM=2.5, P<0.001; odds ratio DM=4.2, P=0.001), while low-glucose concentrations up to 4.9 mmol/l were associated with an increased risk of ICU mortality in the non-DM cohort and up to 3.5 mmol/l in the DM cohort.

CONCLUSION

Mean glucose and high glucose variability are related to ICU mortality in the non-DM cohort but not in the DM cohort. Hypoglycaemia (≤2.2 mmol/l) was associated with ICU mortality in both. The cutoff value for detrimental low glucose is higher in the non-DM cohort (4.9 mmol/l) than in the DM cohort (3.5 mmol/l). While hypoglycaemia (≤2.2 mmol/l) should be avoided in both groups, DM patients seem to tolerate a wider glucose range than non-DM patients.

Central NUCB2/Nesfatin-1-expressing neurones belong to the hypothalamic-brainstem circuitry activated by hypoglycaemia

Nesfatin-1 is a recently identified 82 amino acid peptide shown to have an anorexigenic effect on rodents when administrered centrally and peripherally. Nesfatin-1 is expressed not only in neurones of various brain areas, including the hypothalamic and brainstem nuclei, but also in peripheral organs, such as the stomach and the pancreas. Nesfatinergic neurones were reported to participate in the regulation of satiety signals and in the responses to other stimuli, including restraint stress, abdominal surgery, and lipopolysaccharide-induced inflammation. The present study aimed to investigate whether NUCB2/nesfatin-1 expressing neurones also take part in the central signalling activated in response to hypoglycaemia and therefore are involved in central glucose sensing. Using immunolabelling methods based on the detection of the neuronal activation marker c-Fos and of nesfatin-1, we showed that peripheral injection of insulin induced a strong activation of nesfatin-1-expressing neurones in the brain vagal-regulatory nuclei, including the arcuate nucleus, paraventricular nucleus, lateral hypothalamic area, dorsal motor nucleus of the vagus (DMNX) and nucleus of the tractus solitarius. In response to intracellular glucopaenia induced by i.p. or i.c.v. 2-deoxyglucose injection, the c-Fos/nesfatin-1 colocalisations observed at the hypothalamic and brainstem levels were similar to those observed after insulin-induced hypoglycaemia. Moreover, using Fluorogold as a retrograde tracer, we showed that nesfatinergic preganglionic DMNX neurones activated by hypoglycaemia target the stomach and the pancreas. Taken together, these results suggest that a subpopulation of nesfatinergic neurones belongs to the central network activated by hypoglycaemia, and that nesfatin-1 participates in the triggering of physiological and hormonal counter-regulations observed in response to hypoglycaemia.

Increased expression of adenylyl cyclase 3 in pancreatic islets and central nervous system of diabetic Goto-Kakizaki rats: a possible regulatory role in glucose homeostasis

Adenylyl cyclase 3 (AC3) is expressed in pancreatic islets of the Goto-Kakizaki (GK) rat, a spontaneous animal model of type 2 diabetes (T2D), and also exerts genetic effects on the regulation of body weight in man. In addition to pancreatic islets, the central nervous system (CNS) plays an important role in the pathogenesis of T2D and obesity by regulating feeding behavior, body weight and glucose metabolism. In the present study, we have investigated AC3 expression in pancreatic islets, striatum and hypothalamus of GK rats to evaluate its role in the regulation of glucose homeostasis. GK and Wistar rats at the age of 2.5 mo were used. A group of GK rats were implanted with sustained insulin release chips for 15 d. Plasma glucose and serum insulin levels were measured. AC3 gene expression levels in pancreatic islets, striatum and hypothalamus were determined by using real-time RT-PCR. Results indicated that plasma glucose levels in Wistar rats were found to be similar to insulin-treated GK rats, and significantly lower compared with non-treated GK rats. AC3 expression levels in pancreatic islets, striatum and hypothalamus of GK rats were higher compared with Wistar rats, while the levels were intermediate in insulin-treated GK rats. The AC3 expression display patterns between pancreatic islets and striatum-hypothalamus were similar. The present study thus provides the first evidence that AC3 is overexpressed in the regions of striatum and hypothalamus of brain, and similarly in pancreatic islets of GK rats suggesting that AC3 plays a role in regulation of glucose homeostasis via CNS and insulin secretion.

Insulin-induced recurrent hypoglycemia exacerbates diabetic brain mitochondrial dysfunction and oxidative imbalance

Intensive insulin therapy can prevent or slow the progression of long-term diabetes complications but, at the same time, it increases the risk for episodes of severe hypoglycemia. In our study, we used a protocol intended to mimic the levels of blood glucose that occur in type 1 diabetic patients under an intensive insulin therapy. Streptozotocin (STZ)-induced diabetic rats were treated subcutaneously with twice-daily insulin injections for 2weeks to induce hypoglycemic episodes. Brain cortical and hippocampal mitochondria were isolated and mitochondrial bioenergetics (respiratory chain and phosphorylation system) and oxidative status parameters (malondialdehyde (MDA) levels, mitochondrial aconitase activity and enzymatic and non-enzymatic antioxidant defenses) were analyzed. The protein levels of synaptophysin, a marker of synaptic integrity, and caspase 9 activity were also evaluated in cortical and hippocampal homogenates. Brain cortical mitochondria isolated from hyper- and recurrent hypoglycemic animals presented higher levels of MDA and α-tocopherol together with an increased glutathione disulfide reductase activity, lower manganese superoxide dismutase (MnSOD) activity and glutathione-to-glutathione disulfide (GSH/GSSG) ratio. No significant alterations were found in cortical mitochondrial respiratory chain and oxidative phosphorylation system. Hippocampal mitochondria from both experimental groups presented an impaired oxidative phosphorylation system characterized by a decreased mitochondrial energization potential and ATP levels and higher repolarization lag phase. In addition, higher MDA levels and decreased GSH/GSSG, α-tocopherol levels, and aconitase, glutathione peroxidase and MnSOD activities were observed in both groups of animals. Hippocampal mitochondria from recurrent hypoglycemic animals also showed an impairment of the respiratory chain characterized by a lower state 3 of respiration, respiratory control ratio and ADP/O index, and a higher state 4 of respiration. Additionally, a non-statistically significant decrease in synaptophysin protein levels was observed in cortical homogenates from recurrent hypoglycemic rats as well as in hippocampal homogenates from hyperglycemic and recurrent hypoglycemic rats. An increase in caspase 9 activity was also observed in hippocampal homogenates from hyperglycemic and recurrent hypoglycemic animals. Our results show that mitochondrial dysfunction induced by long-term hyperglycemic effects is exacerbated by recurrent hypoglycemia, which may compromise the function and integrity of brain cells.