scholarly journals O9.2. ANTIPSYCHOTIC DRUGS IMPAIR BRAIN GLUCOSE SENSING RESULTING IN WHOLE BODY INSULIN RESISTANCE

2020 ◽  
Vol 46 (Supplement_1) ◽  
pp. S21-S21
Author(s):  
Laura Castellani ◽  
Chantel Kowalchuk ◽  
Roshanak Asgariroozbehani ◽  
Veronica Tran ◽  
William Brett McIntyre ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Metabolism ◽  
Infusion Rate ◽  
Second Generation ◽  
Glucose Sensing ◽  
Glucose Infusion ◽  
Whole Body ◽  
Glucose Kinetics ◽  
Brain Glucose

Abstract Background Antipsychotics (APs) remain the cornerstone treatment for schizophrenia, and are widely used on- and off-label for other psychiatric disorders. However, their use presents a significant risk for serious adverse glycemic effects. Independent of changes in adiposity, APs directly dysregulate whole body glucose metabolism, and this may occur through the central nervous system (CNS). To this end, we have recently demonstrated that the second-generation AP, olanzapine, impairs hypothalamic insulin-action, resulting in dysregulation of whole-body insulin sensitivity. In addition to a critical role of hormones such as insulin in the CNS, glucose-sensing at the hypothalamus is also pivotal for the regulation of whole-body insulin sensitivity. Glucose also represents the primary fuel for brain function, and the hypothalamus represents the key brain center (through glucose sensing neurons) to partition resources to ensure maintenance of key homeostatic systems. In the current study, we set out to examine the effects of a first generation AP (e.g. haloperidol) and second-generation AP(e.g. olanzapine) on hypothalamic-glucose sensing, and subsequent regulation of peripheral glucose metabolism. Methods Gold-standard, pancreatic-euglycemic clamps were used to assess changes in glucose kinetics in response to a primed, continuous intracerebroventricular (ICV) infusion of glucose or vehicle solution (2mM, 5μL/hour, into the 3rd ventricle). Male rats were co-treated with an acute injection of olanzapine (3mg/kg, S.C.), haloperidol (10mg/kg, S.C.) or a weight adjusted vehicle solution. Dosing of APs was based on clinical D2 occupancies. Groups included (ICV–peripheral) vehicle–vehicle (n = 6), glucose–vehicle (n = 8), glucose–olanzapine (n = 6), vehicle–olanzapine (n = 6), glucose-haloperidol (n = 6) and vehicle-haloperidol (n = 7). The peripheral glucose infusion rate needed to maintain euglycemia during the clamp was used as a measure of whole-body insulin sensitivity. Results As expected and previously demonstrated, ICV (central) glucose infusion caused a significant increase in the peripheral glucose infusion rate of glucose (mg/kg.min) compared to vehicle treated rats (Veh-Veh 3.11±0.73 vs Glu-Veh 8.39±1.61), p<0.05). This effect was mitigated by treatment with both olanzapine (Glu-Veh 8.39±1.61, Glu-Ola 0.63±0.37, p<0.05) and haloperidol (Glu-Veh 8.39±1.61, Glu-Hal 3.01±0.46, p<0.05). In summary, olanzapine and haloperidol both impaired central glucose sensing resulting in whole body insulin resistance. Discussion Hypothalamic glucose-sensing is critical for the regulation of peripheral glucose homeostasis. This data, for the first time, demonstrates evidence that both first- and second-generation APs disrupt hypothalamic glucose-mediated regulation of glucose kinetics. Perturbed glucose-sensing in the CNS is expected to have deleterious consequences for metabolic homeostasis, and possibly other brain glucose-dependent functions such as cognition. The study unveils a novel effect of AP treatment to disrupt brain nutrient-sensing, suggesting this may be a mechanism by which these drugs increase risk of type 2 diabetes.

A1 adenosine receptor partial agonist lowers plasma FFA and improves insulin resistance induced by high-fat diet in rodents

2007 ◽  
Vol 292 (5) ◽  
pp. E1358-E1363 ◽  
Author(s):  
Arvinder K. Dhalla ◽  
Mei Yee Wong ◽  
Peter J. Voshol ◽  
Luiz Belardinelli ◽  
Gerald M. Reaven
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Adenosine Receptor ◽  
Infusion Rate ◽  
Glucose Infusion ◽  
Glucose Infusion Rate ◽  
Oral Glucose ◽  
Acute Administration ◽  
High Fat ◽  
Adenosine Receptor Agonist

There is substantial evidence in the literature that elevated plasma free fatty acids (FFA) play a role in the pathogenesis of type 2 diabetes. CVT-3619 is a selective partial A1 adenosine receptor agonist that inhibits lipolysis and lowers circulating FFA. The present study was undertaken to determine the effect of CVT-3619 on insulin resistance induced by high-fat (HF) diet in rodents. HF diet feeding to rats for 2 wk caused a significant increase in insulin, FFA, and triglyceride (TG) concentrations compared with rats fed chow. CVT-3619 (1 mg/kg) caused a time-dependent decrease in fasting insulin, FFA, and TG concentrations. Acute administration of CVT-3619 significantly lowered the insulin response, whereas glucose response was not different with an oral glucose tolerance test. Treatment with CVT-3619 for 2 wk resulted in significant lowering of FFA, TG, and insulin concentrations in rats on HF diet. To determine the effect of CVT-3619 on insulin sensitivity, hyperinsulinemic euglycemic clamp studies were performed in C57BL/J6 mice fed HF diet for 12 wk. Glucose infusion rate was decreased significantly in HF mice compared with chow-fed mice. CVT-3619 treatment 15 min prior to the clamp study significantly ( P < 0.01) increased glucose infusion rate to values similar to that for chow-fed mice. In conclusion, CVT-3619 treatment lowers FFA and TG concentrations and improves insulin sensitivity in rodent models of insulin resistance.

scholarly journals The PERSonalized Glucose Optimization Through Nutritional Intervention (PERSON) Study: Rationale, Design and Preliminary Screening Results

2021 ◽  
Vol 8 ◽  
Author(s):  
Anouk Gijbels ◽  
Inez Trouwborst ◽  
Kelly M. Jardon ◽  
Gabby B. Hul ◽  
Els Siebelink ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Skeletal Muscle ◽  
Insulin Sensitivity ◽  
Glucose Metabolism ◽  
Dietary Intervention ◽  
Hepatic Insulin Resistance ◽  
Whole Body ◽  
Primary Study ◽  
Sensitivity Index ◽  
Tissue Specific

Background: It is well-established that the etiology of type 2 diabetes differs between individuals. Insulin resistance (IR) may develop in different tissues, but the severity of IR may differ in key metabolic organs such as the liver and skeletal muscle. Recent evidence suggests that these distinct tissue-specific IR phenotypes may also respond differentially to dietary macronutrient composition with respect to improvements in glucose metabolism.Objective: The main objective of the PERSON study is to investigate the effects of an optimal vs. suboptimal dietary macronutrient intervention according to tissue-specific IR phenotype on glucose metabolism and other health outcomes.Methods: In total, 240 overweight/obese (BMI 25 – 40 kg/m2) men and women (age 40 – 75 years) with either skeletal muscle insulin resistance (MIR) or liver insulin resistance (LIR) will participate in a two-center, randomized, double-blind, parallel, 12-week dietary intervention study. At screening, participants undergo a 7-point oral glucose tolerance test (OGTT) to determine the hepatic insulin resistance index (HIRI) and muscle insulin sensitivity index (MISI), classifying each participant as either “No MIR/LIR,” “MIR,” “LIR,” or “combined MIR/LIR.” Individuals with MIR or LIR are randomized to follow one of two isocaloric diets varying in macronutrient content and quality, that is hypothesized to be either an optimal or suboptimal diet, depending on their tissue-specific IR phenotype (MIR/LIR). Extensive measurements in a controlled laboratory setting as well as phenotyping in daily life are performed before and after the intervention. The primary study outcome is the difference in change in disposition index, which is the product of insulin sensitivity and first-phase insulin secretion, between participants who received their hypothesized optimal or suboptimal diet.Discussion: The PERSON study is one of the first randomized clinical trials in the field of precision nutrition to test effects of a more personalized dietary intervention based on IR phenotype. The results of the PERSON study will contribute knowledge on the effectiveness of targeted nutritional strategies to the emerging field of precision nutrition, and improve our understanding of the complex pathophysiology of whole body and tissue-specific IR.Clinical Trial Registration:https://clinicaltrials.gov/ct2/show/NCT03708419, clinicaltrials.gov as NCT03708419.

scholarly journals Growth hormone receptor antagonism with pegvisomant in insulin resistant non-diabetic men: A phase II pilot study

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 614 ◽  
Author(s):  
Ada P. Lee ◽  
Kathleen Mulligan ◽  
Morris Schambelan ◽  
Elizabeth J. Murphy ◽  
Ethan J. Weiss
Keyword(s):  
Insulin Resistance ◽  
Growth Hormone ◽  
Insulin Sensitivity ◽  
Pilot Study ◽  
Glucose Metabolism ◽  
Phase Ii ◽  
Whole Body ◽  
Sensitivity Index ◽  
Insulin Resistant ◽  
Gh Receptor

Background: Growth hormone (GH) is known to affect insulin and glucose metabolism.  Blocking its effects in acromegalic patients improves diabetes and glucose metabolism. We aimed to determine the effect of pegvisomant, a GH receptor antagonist, on insulin resistance, endogenous glucose production (EGP) and lipolysis in insulin resistant non-diabetic men.  Methods: Four men between the ages of 18-62 with a BMI of 18-35kg/m2, with insulin resistance as defined by a HOMA-IR > 2.77, were treated for four weeks with pegvisomant 20 mg daily.  Inpatient metabolic assessments were performed before and after treatment. The main outcome measurements were: change after pegvisomant therapy in insulin sensitivity as measured by hyperinsulinemic euglycemic clamp; and EGP and lipolysis assessed by stable isotope tracer techniques. Results: Insulin like growth factor-1 (IGF-1) concentrations decreased from 134.0 ± 41.5 (mean ± SD) to 72.0 ± 11.7 ng/mL (p = 0.04) after 4 weeks of therapy. Whole body insulin sensitivity index (M/I 3.2 ± 1.3 vs. 3.4 ± 2.4; P = 0.82), as well as suppression of EGP (89.7 ± 26.9 vs. 83.5 ± 21.6%; p = 0.10) and Ra glycerol (59.4 ± 22.1% vs. 61.2 ± 14.4%; p = 0.67) during the clamp were not changed significantly with pegvisomant treatment. Conclusions: Blockade of the GH receptor with pegvisomant for four weeks had no significant effect on insulin/glucose metabolism in a small phase II pilot study of non-diabetic insulin resistant participants without acromegaly.

scholarly journals Sex-specific programming of adult insulin resistance in guinea pigs by variable perinatal growth induced by spontaneous variation in litter size

2019 ◽  
Vol 316 (4) ◽  
pp. R352-R361
Author(s):  
Dane M. Horton ◽  
David A. Saint ◽  
Kathryn L. Gatford ◽  
Karen L. Kind ◽  
Julie A. Owens
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Metabolism ◽  
Guinea Pigs ◽  
Glucose Utilization ◽  
Glucose Production ◽  
Endogenous Glucose Production ◽  
Whole Body ◽  
Catch Up ◽  
Endogenous Glucose

Intrauterine growth restriction (IUGR) and subsequent neonatal catch-up growth are implicated in programming of insulin resistance later in life. Spontaneous IUGR in the guinea pig, due to natural variation in litter size, produces offspring with asymmetric IUGR and neonatal catch-up growth. We hypothesized that spontaneous IUGR and/or accelerated neonatal growth would impair insulin sensitivity in adult guinea pigs. Insulin sensitivity of glucose metabolism was determined by hyperinsulinemic-euglycemic clamp (HEC) in 38 (21 male, 17 female) young adult guinea pigs from litters of two-to-four pups. A subset (10 male, 8 female) were infused with d-[3-3H]glucose before and during the HEC to determine rates of basal and insulin-stimulated glucose utilization, storage, glycolysis, and endogenous glucose production. n males, the insulin sensitivity of whole body glucose uptake ( r = 0.657, P = 0.002) and glucose utilization ( r = 0.884, P = 0.004) correlated positively and independently with birth weight, but not with neonatal fractional growth rate (FGR10–28). In females, the insulin sensitivity of whole body and partitioned glucose metabolism was not related to birth weight, but that of endogenous glucose production correlated negatively and independently with FGR10–28 ( r = −0.815, P = 0.025). Thus, perinatal growth programs insulin sensitivity of glucose metabolism in the young adult guinea pig and in a sex-specific manner; impaired insulin sensitivity, including glucose utilization, occurs after IUGR in males and impaired hepatic insulin sensitivity after rapid neonatal growth in females.

scholarly journals Glucose mediates insulin sensitivity via a hepatoportal mechanism in high-fat-fed rats

2019 ◽  
Vol 241 (3) ◽  
pp. 189-199 ◽  
Author(s):  
Holly M Johnson ◽  
Erin Stanfield ◽  
Grace J Campbell ◽  
Erica E Eberl ◽  
Gregory J Cooney ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
High Fat Diet ◽  
Glucose Infusion ◽  
Whole Body ◽  
Glucose Turnover ◽  
Oral Glucose ◽  
Glucose Load ◽  
High Fat ◽  
Whole Body Metabolism

Poor nutrition plays a fundamental role in the development of insulin resistance, an underlying characteristic of type 2 diabetes. We have previously shown that high-fat diet-induced insulin resistance in rats can be ameliorated by a single glucose meal, but the mechanisms for this observation remain unresolved. To determine if this phenomenon is mediated by gut or hepatoportal factors, male Wistar rats were fed a high-fat diet for 3 weeks before receiving one of five interventions: high-fat meal, glucose gavage, high-glucose meal, systemic glucose infusion or portal glucose infusion. Insulin sensitivity was assessed the following day in conscious animals by a hyperinsulinaemic-euglycaemic clamp. An oral glucose load consistently improved insulin sensitivity in high-fat-fed rats, establishing the reproducibility of this model. A systemic infusion of a glucose load did not affect insulin sensitivity, indicating that the physiological response to oral glucose was not due solely to increased glucose turnover or withdrawal of dietary lipid. A portal infusion of glucose produced the largest improvement in insulin sensitivity, implicating a role for the hepatoportal region rather than the gastrointestinal tract in mediating the effect of glucose to improve lipid-induced insulin resistance. These results further deepen our understanding of the mechanism of glucose-mediated regulation of insulin sensitivity and provide new insight into the role of nutrition in whole body metabolism.

Dose-response relationships for the effects of insulin on glucose and fat metabolism in injured patients and control subjects

1991 ◽  
Vol 80 (1) ◽  
pp. 25-32 ◽  
Author(s):  
Alistair A. Henderson ◽  
Keith N. Frayn ◽  
Charles S. B. Galasko ◽  
Roderick A. Little
Keyword(s):  
Insulin Resistance ◽  
Dose Response ◽  
Infusion Rate ◽  
Plasma Insulin ◽  
Insulin Infusion ◽  
Glucose Infusion ◽  
Whole Body ◽  
Control Subjects ◽  
Injured Patients ◽  
And Control

1. Twenty-four patients were studied at around 7 days after musculoskeletal injuries in order to define the nature of the impairment of sensitivity to insulin. Insulin was infused at 6, 35, 200 or 1200 m-units min−1 m−2 for 2 h and the plasma glucose concentration was ‘clamped’ at 5 mmol/l. Forearm (uninjured) glucose extraction and blood flow were measured, and whole-body substrate oxidation and energy production rates were assessed by indirect calorimetry. The patients were compared with normal control subjects. 2. Plasma insulin concentrations during infusion were similar in patients and control subjects, showing a similar metabolic clearance of insulin. At each infusion rate, the rate of glucose infusion needed to maintain euglycaemia was less in the patients than in the control subjects. The dose-response curve for whole-body glucose infusion rate against plasma insulin concentration showed diminished sensitivity and diminished maximal response in the patients. A similar pattern was seen for forearm glucose uptake, with a marked impairment of both sensitivity to insulin and maximal responsiveness. 3. The resting metabolic rate was increased in the patients compared with the control subjects, but failed to respond to insulin infusion, so that final metabolic rates were similar in patients and control subjects. At the higher insulin infusion rates, the final rate of whole-body oxidation of carbohydrate was significantly less in the patients than in the control subjects, and that of fat was significantly greater. 4. The hormonal background to this picture of insulin resistance was not striking: the injured patients showed small elevations in plasma cortisol, glucagon and noradrenaline concentrations, but not in plasma adrenaline concentration. 5. It is concluded that the insulin resistance after injury reflects both diminished responsiveness and diminished sensitivity, affects both fat and carbohydrate metabolism, and must be explained by factors other than the usually considered ‘counter-regulatory’ hormones.

scholarly journals Antisense oligonucleotides against monoacylglycerol acyltransferase 1 (Mogat1) improve glucose metabolism independently of Mogat1

2020 ◽  
Author(s):  
Andrew J. Lutkewitte ◽  
Jason M. Singer ◽  
Trevor M. Shew ◽  
Michael R. Martino ◽  
Angela M. Hall ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Glucose Metabolism ◽  
Glucose Tolerance ◽  
High Fat Diet ◽  
Hepatic Insulin Resistance ◽  
Whole Body ◽  
High Fat ◽  
Target Effects ◽  
Monoacylglycerol Acyltransferase

ABSTRACTObjectiveMonoacylglycerol acyltransferase (MGAT) enzymes catalyze the synthesis of diacylglycerol from monoacylglycerol. Previous work has suggested the importance of MGAT activity in the development of obesity-related hepatic insulin resistance. Indeed, antisense oligonucleotide (ASO)-mediated knockdown of the gene encoding MGAT1, Mogat1, reduced hepatic MGAT activity and improved glucose tolerance and insulin resistance in high fat diet (HFD) fed mice. However, recent work has suggested that some ASOs may have off-target effects on body weight and metabolic parameters via activation of the interferon alpha/beta receptor 1 (IFNAR-1) pathway.MethodsMice with whole-body Mogat1 knockout or a floxed allele for Mogat1 to allow for liver-specific Mogat1-knockout (by either a liver-specific transgenic or adeno-associated virus-driven Cre recombinase) were generated. These mice were placed on a high fat diet and glucose metabolism and insulin sensitivity was assessed after 16 weeks on diet. In some experiments, mice were treated with control or Mogat1 or control ASOs in the presence or absence of IFNAR-1 neutralizing antibody.ResultsGenetic deletion of hepatic Mogat1, either acutely or chronically, did not improve hepatic steatosis, glucose tolerance, or insulin sensitivity in HFD-fed mice. Furthermore, constitutive Mogat1 knockout in all tissues actually exacerbated HFD-induced weight gain, insulin resistance, and glucose intolerance on a HFD. Despite markedly reduced Mogat1 expression, liver MGAT activity was unaffected in all knockout mouse models. Mogat1 overexpression hepatocytes increased liver MGAT activity and TAG content in low-fat fed mice, but did not cause insulin resistance. Interestingly, Mogat1 ASO treatment improved glucose tolerance in both wild-type and Mogat1 null mice, suggesting an off target effect. Inhibition of IFNAR-1 did not block the effect of Mogat1 ASO on glucose homeostasis.ConclusionThese results indicate that genetic loss of Mogat1 does not affect hepatic MGAT activity or metabolic homeostasis on HFD and show that Mogat1 ASOs improve glucose metabolism through effects independent of targeting Mogat1 or activation of IFNAR-1 signaling.Abstract FigureHighlightsMogat1 liver-specific KO or KD does not improve metabolism in HFD fed mice.Whole-body Mogat1-deletion impairs insulin tolerance in HFD fed mice.Mogat1 ASOs improves whole body metabolism independently of gene knockdown.Blockade of the INFR response does not prevent off-target effects of Mogat1 ASOs.

scholarly journals Brain Glucose Metabolism in Health, Obesity, and Cognitive Decline—Does Insulin Have Anything to Do with It? A Narrative Review

2021 ◽  
Vol 10 (7) ◽  
pp. 1532
Author(s):  
Eleni Rebelos ◽  
Juha O. Rinne ◽  
Pirjo Nuutila ◽  
Laura L. Ekblad
Keyword(s):  
Insulin Resistance ◽  
Glucose Metabolism ◽  
Cognitive Decline ◽  
Fdg Pet ◽  
Metabolic Disorders ◽  
Brain Glucose ◽  
Brain Glucose Metabolism ◽  
Systemic Insulin Resistance ◽  
Increased Risk ◽  
18F Fdg

Imaging brain glucose metabolism with fluorine-labelled fluorodeoxyglucose ([18F]-FDG) positron emission tomography (PET) has long been utilized to aid the diagnosis of memory disorders, in particular in differentiating Alzheimer’s disease (AD) from other neurological conditions causing cognitive decline. The interest for studying brain glucose metabolism in the context of metabolic disorders has arisen more recently. Obesity and type 2 diabetes—two diseases characterized by systemic insulin resistance—are associated with an increased risk for AD. Along with the well-defined patterns of fasting [18F]-FDG-PET changes that occur in AD, recent evidence has shown alterations in fasting and insulin-stimulated brain glucose metabolism also in obesity and systemic insulin resistance. Thus, it is important to clarify whether changes in brain glucose metabolism are just an epiphenomenon of the pathophysiology of the metabolic and neurologic disorders, or a crucial determinant of their pathophysiologic cascade. In this review, we discuss the current knowledge regarding alterations in brain glucose metabolism, studied with [18F]-FDG-PET from metabolic disorders to AD, with a special focus on how manipulation of insulin levels affects brain glucose metabolism in health and in systemic insulin resistance. A better understanding of alterations in brain glucose metabolism in health, obesity, and neurodegeneration, and the relationships between insulin resistance and central nervous system glucose metabolism may be an important step for the battle against metabolic and cognitive disorders.

scholarly journals Imaging of brain glucose uptake by PET in obesity and cognitive dysfunction: life-course perspective

2019 ◽  
Vol 8 (11) ◽  
pp. R169-R183 ◽  
Author(s):  
Patricia Iozzo ◽  
Maria Angela Guzzardi
Keyword(s):  
Insulin Resistance ◽  
Life Course ◽  
Glucose Uptake ◽  
Cognitive Dysfunction ◽  
Brain Metabolism ◽  
Life Course Perspective ◽  
Whole Body ◽  
Current Evidence ◽  
Brain Glucose

The prevalence of obesity has reached epidemic proportions and keeps growing. Obesity seems implicated in the pathogenesis of cognitive dysfunction, Alzheimer’s disease and dementia, and vice versa. Growing scientific efforts are being devoted to the identification of central mechanisms underlying the frequent association between obesity and cognitive dysfunction. Glucose brain handling undergoes dynamic changes during the life-course, suggesting that its alterations might precede and contribute to degenerative changes or signaling abnormalities. Imaging of the glucose analog 18F-labeled fluorodeoxyglucose (18FDG) by positron emission tomography (PET) is the gold-standard for the assessment of cerebral glucose metabolism in vivo. This review summarizes the current literature addressing brain glucose uptake measured by PET imaging, and the effect of insulin on brain metabolism, trying to embrace a life-course vision in the identification of patterns that may explain (and contribute to) the frequent association between obesity and cognitive dysfunction. The current evidence supports that brain hypermetabolism and brain insulin resistance occur in selected high-risk conditions as a transient phenomenon, eventually evolving toward normal or low values during life or disease progression. Associative studies suggest that brain hypermetabolism predicts low BDNF levels, hepatic and whole body insulin resistance, food desire and an unfavorable balance between anticipated reward from food and cognitive inhibitory control. Emerging mechanistic links involve the microbiota and the metabolome, which correlate with brain metabolism and cognition, deserving attention as potential future prevention targets.

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