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Bell SM, Hariharan R, Laud PJ, Majid A, de Courten B. Histidine-containing dipeptide supplementation improves delayed recall: a systematic review and meta-analysis. Nutr Rev 2024; 82:1372-1385. [PMID: 38013229 DOI: 10.1093/nutrit/nuad135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023] Open
Abstract
CONTEXT Histidine-containing dipeptides (carnosine, anserine, beta-alanine and others) are found in human muscle tissue and other organs like the brain. Data in rodents and humans indicate that administration of exogenous carnosine improved cognitive performance. However, RCTs results vary. OBJECTIVES To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) of histidine-containing dipeptide (HCD) supplementation on cognitive performance in humans to assess its utility as a cognitive stabiliser. DATA SOURCES OVID Medline, Medline, EBM Reviews, Embase, and Cumulative Index to Nursing and Allied Health Literature databases from 1/1/1965 to 1/6/2022 for all RCT of HCDs were searched. DATA EXTRACTION 2653 abstracts were screened, identifying 94 full-text articles which were assessed for eligibility. Ten articles reporting the use of HCD supplementation were meta-analysed. DATA ANALYSIS The random effects model has been applied using the DerSimonian-Laird method. HCD treatment significantly increased performance on Wechsler Memory Scale (WMS) -2 Delayed recall (Weighted mean difference (WMD) (95% CI (CI)) = 1.5 (0.6, 2.5), P < .01). Treatment with HCDs had no effect on Alzheimer's Disease Assessment Scale-Cognitive (WMD (95% CI) = -0.2 (-1.1, 0.7), P = .65, I2 = 0%), Mini-Mental State Examination (WMD (95% CI) = 0.7 (-0.2, 1.5), P = .14, I2 = 42%), The Wechsler Adult Intelligence Scale (WAIS) Digit span Backward (WMD (95% CI) = 0.1 (-0.3, 0.5), P = .51, I2 = 0%), WAIS digit span Forward (WMD (95% CI) = 0.0 (-0.3, 0.4), P = .85, I2 = 33%) and the WMS-1 Immediate recall (WMD (95% CI) = .7 (-.2, 1.5), P = .11, I2 = 0%). The effect on delayed recall remained in subgroup meta-analysis performed on studies of patients without mild cognitive impairment (MCI), and in those without MCI where average age in the study was above 65. CONCLUSION HCD, supplementation improved scores on the Delayed recall examination, a neuropsychological test affected early in Alzheimer's disease. Further studies are needed in people with early cognitive impairment with longer follow-up duration and standardization of carnosine doses to delineate the true effect. SYSTEMATIC REVIEW REGISTRATION PROSPERO registration no. CRD42017075354.
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Affiliation(s)
- Simon M Bell
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Rohit Hariharan
- Department of Medicine, School of Clinical Sciences, Monash University, Australia
| | - Peter J Laud
- Statistical Services Unit, University of Sheffield, Sheffield, UK
| | - Arshad Majid
- Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield, UK
| | - Barbora de Courten
- Department of Medicine, School of Clinical Sciences, Monash University, Australia
- Health & Biomedical Sciences, STEM College, RMIT University, Melbourne, VIC, Australia
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Ferraz L, Barros M, Almeida K, Silva M, Bueno N. Effects of dietary supplementation in treatment and control of progression and complications of insulin-dependent diabetes mellitus: a systematic review with meta-analyses of randomized clinical trials. Braz J Med Biol Res 2024; 57:e13649. [PMID: 39194033 PMCID: PMC11349153 DOI: 10.1590/1414-431x2024e13649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Accepted: 06/19/2024] [Indexed: 08/29/2024] Open
Abstract
There is no safe and effective prevention for insulin-dependent diabetes (IDDM) mellitus, which makes it highly dependent on its treatment. This systematic review with meta-analyses of randomized clinical trials investigated the overall effects of dietary supplements of vitamins, minerals, trace elements, and non-essential compounds with antioxidant properties, fatty acids, and amino acids in IDDM. Searches of MEDLINE, Embase, CENTRAL, LILACS, The Grey Literature Report, and ClinicaTrials.gov, and citations from previous reviews were used to identify reports published through July 2023. The Risk of Bias 2 (RoB2) tool was used to analyze the risk of bias and GRADE was used to assess the quality of the results. Fifty-eight studies (n=3,044) were included in qualitative analyses and seventeen (n=723) in meta-analyses. Qualitative analyses showed few positive effects on some metabolic function markers, such as endothelial and renal function and lipid profile. Meta-analyses showed a positive effect of omega-3 on glycated hemoglobin (HbA1c) (RMD=-0.33; 95%CI: -0.53, -0.12, P=0.002; I2=0%; GRADE: low quality; 4 studies) and of vitamin D on fasting C-peptide (FCP) (RMD=0.05; 95%CI: 0.01, 0.9, P=0.023; I2=0%; GRADE: very low quality; 4 studies). Most studies showed bias concern or high risk of bias. A recommendation for dietary supplementation in IDDM cannot be made because of the few positive results within different interventions and markers, the serious risk of bias in the included studies, and the low quality of evidence from meta-analyses. The positive result of vitamin D on FCP is preliminary, requiring further investigation.
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Affiliation(s)
- L.C. Ferraz
- Laboratório de Nutrição e Metabolismo, Faculdade de Nutrição, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - M.D.R. Barros
- Laboratório de Nutrição e Metabolismo, Faculdade de Nutrição, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - K.M.M. Almeida
- Laboratório de Nutrição e Metabolismo, Faculdade de Nutrição, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - M.B.G. Silva
- Laboratório de Nutrição e Metabolismo, Faculdade de Nutrição, Universidade Federal de Alagoas, Maceió, AL, Brasil
| | - N.B. Bueno
- Laboratório de Nutrição e Metabolismo, Faculdade de Nutrição, Universidade Federal de Alagoas, Maceió, AL, Brasil
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Hill TG, Hill DJ. The Importance of Intra-Islet Communication in the Function and Plasticity of the Islets of Langerhans during Health and Diabetes. Int J Mol Sci 2024; 25:4070. [PMID: 38612880 PMCID: PMC11012451 DOI: 10.3390/ijms25074070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/27/2024] [Accepted: 03/27/2024] [Indexed: 04/14/2024] Open
Abstract
Islets of Langerhans are anatomically dispersed within the pancreas and exhibit regulatory coordination between islets in response to nutritional and inflammatory stimuli. However, within individual islets, there is also multi-faceted coordination of function between individual beta-cells, and between beta-cells and other endocrine and vascular cell types. This is mediated partly through circulatory feedback of the major secreted hormones, insulin and glucagon, but also by autocrine and paracrine actions within the islet by a range of other secreted products, including somatostatin, urocortin 3, serotonin, glucagon-like peptide-1, acetylcholine, and ghrelin. Their availability can be modulated within the islet by pericyte-mediated regulation of microvascular blood flow. Within the islet, both endocrine progenitor cells and the ability of endocrine cells to trans-differentiate between phenotypes can alter endocrine cell mass to adapt to changed metabolic circumstances, regulated by the within-islet trophic environment. Optimal islet function is precariously balanced due to the high metabolic rate required by beta-cells to synthesize and secrete insulin, and they are susceptible to oxidative and endoplasmic reticular stress in the face of high metabolic demand. Resulting changes in paracrine dynamics within the islets can contribute to the emergence of Types 1, 2 and gestational diabetes.
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Affiliation(s)
- Thomas G. Hill
- Oxford Centre for Diabetes, Endocrinology, and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, UK
| | - David J. Hill
- Lawson Health Research Institute, St. Joseph’s Health Care, London, ON N6A 4V2, Canada;
- Departments of Medicine, Physiology and Pharmacology, Western University, London, ON N6A 3K7, Canada
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Warner SO, Dai Y, Sheanon N, Yao MV, Cason RL, Arbabi S, Patel SB, Lindquist D, Winnick JJ. Short-term fasting lowers glucagon levels under euglycemic and hypoglycemic conditions in healthy humans. JCI Insight 2023; 8:e169789. [PMID: 37166980 PMCID: PMC10371233 DOI: 10.1172/jci.insight.169789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/09/2023] [Indexed: 05/12/2023] Open
Abstract
Fasting is associated with increased susceptibility to hypoglycemia in people with type 1 diabetes, thereby making it a significant health risk. To date, the relationship between fasting and insulin-induced hypoglycemia has not been well characterized, so our objective was to determine whether insulin-independent factors, such as counterregulatory hormone responses, are adversely impacted by fasting in healthy control individuals. Counterregulatory responses to insulin-induced hypoglycemia were measured in 12 healthy people during 2 metabolic studies. During one study, participants ate breakfast and lunch, after which they underwent a 2-hour bout of insulin-induced hypoglycemia (FED). During the other study, participants remained fasted prior to hypoglycemia (FAST). As expected, hepatic glycogen concentrations were lower in FAST, and associated with diminished peak glucagon levels and reduced endogenous glucose production (EGP) during hypoglycemia. Accompanying lower EGP in FAST was a reduction in peripheral glucose utilization, and a resultant reduction in the amount of exogenous glucose required to maintain glycemia. These data suggest that whereas a fasting-induced lowering of glucose utilization could potentially delay the onset of insulin-induced hypoglycemia, subsequent reductions in glucagon levels and EGP are likely to encumber recovery from it. As a result of this diminished metabolic flexibility in response to fasting, susceptibility to hypoglycemia could be enhanced in patients with type 1 diabetes under similar conditions.
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Affiliation(s)
- Shana O. Warner
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Yufei Dai
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Nicole Sheanon
- Department of Pediatrics, Division of Pediatric Endocrinology, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Michael V. Yao
- Department of Pediatrics, Division of Endocrinology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Rebecca L. Cason
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Shahriar Arbabi
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Shailendra B. Patel
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Diana Lindquist
- Imaging Research Center, Department of Radiology, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
| | - Jason J. Winnick
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
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Rokamp KZ, Holst JJ, Olsen NV, Dela F, Secher NH, Juul A, Faber J, Wiberg S, Thorsteinsson B, Pedersen-Bjergaard U. Impact of Polymorphism in the β2-Receptor Gene on Metabolic Responses to Repeated Hypoglycemia in Healthy Humans. J Clin Endocrinol Metab 2022; 107:e3194-e3205. [PMID: 35552407 DOI: 10.1210/clinem/dgac297] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Indexed: 11/19/2022]
Abstract
CONTEXT The Arg16 variant in the β2-receptor gene is associated with increased risk of severe hypoglycemia in subjects with type 1 diabetes mellitus. OBJECTIVE We hypothesized that the Arg16 variant is associated with decreased metabolic and symptomatic responses to recurrent hypoglycemia. METHODS Twenty-five healthy male subjects selected according to ADRB2 genotype and being homozygous for either Arg16 (AA; n = 13) or Gly16 (GG; n = 12) participated in 2 consecutive trial days with 3 periods of hypoglycemia (H1-H3) induced by a hyperinsulinemic hypoglycemic clamp. The main outcome measure was mean glucose infusion rate (GIR) during H1-H3. RESULTS During H1-H3, there was no difference between AA or GG subjects in GIR, counter-regulatory hormones (glucagon, epinephrine, cortisol, growth hormone), or substrate levels of lactate, glycerol, and free fatty acids (FFAs), and no differences in symptom response score or cognitive performance (trail making test, Stroop test). At H3, lactate response was reduced in both genotype groups, but AA subjects had decreased response (mean ± standard error of the mean of area under the curve) of glycerol (-13.1 ± 3.8 μmol L-1 hours; P = .0052), FFA (-30.2 ± 11.1 μmol L-1 hours; P = .021), and β-hydroxybutyrate (-0.008 ± 0.003 mmol L-1 hour; P = .027), while in GG subjects alanine response was increased (negative response values) (-53.9 ± 20.6 μmol L-1 hour; P = .024). CONCLUSION There was no difference in GIR between genotype groups, but secondary outcomes suggest a downregulation of the lipolytic and β-hydroxybutyrate responses to recurrent hypoglycemia in AA subjects, in contrast to the responses in GG subjects.
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Affiliation(s)
- Kim Zillo Rokamp
- Endocrine Section, Department of Endocrinology and Nephrology, Copenhagen University Hospital, Nordsjællands Hospital, Hillerød, Denmark
- Department of Anaesthesia, Zealand University Hospital, Køge, Denmark
- Department of Neuroanaesthesia, Copenhagen University Hospital, Rigshospitalet-Glostrup, Glostrup, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- The NNF Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
- Departments of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
| | - Niels V Olsen
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Flemming Dela
- Biomedical Science, University of Copenhagen, Copenhagen, Denmark
- Department of Geriatrics, Copenhagen University Hospital, Bispebjerg-Frederiksberg Hospital, Copenhagen, Denmark
| | - Niels H Secher
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Departments of Anaesthesia, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Anders Juul
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Growth and Reproduction, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark
| | - Jens Faber
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Department of Endocrinology, Copenhagen University Hospital, Herlev-Gentofte Hospital, Copenhagen, Denmark
| | - Sebastian Wiberg
- Department of Anaesthesia, Zealand University Hospital, Køge, Denmark
| | - Birger Thorsteinsson
- Endocrine Section, Department of Endocrinology and Nephrology, Copenhagen University Hospital, Nordsjællands Hospital, Hillerød, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Ulrik Pedersen-Bjergaard
- Endocrine Section, Department of Endocrinology and Nephrology, Copenhagen University Hospital, Nordsjællands Hospital, Hillerød, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
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Colberg SR. Why Glucagon Matters for Hypoglycemia and Physical Activity in Individuals With Type 1 Diabetes. FRONTIERS IN CLINICAL DIABETES AND HEALTHCARE 2022; 3:889248. [PMID: 36992764 PMCID: PMC10012082 DOI: 10.3389/fcdhc.2022.889248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 06/15/2022] [Indexed: 11/13/2022]
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Porcellati F, Di Mauro S, Mazzieri A, Scamporrino A, Filippello A, De Fano M, Fanelli CG, Purrello F, Malaguarnera R, Piro S. Glucagon as a Therapeutic Approach to Severe Hypoglycemia: After 100 Years, Is It Still the Antidote of Insulin? Biomolecules 2021; 11:biom11091281. [PMID: 34572493 PMCID: PMC8464883 DOI: 10.3390/biom11091281] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 08/23/2021] [Accepted: 08/26/2021] [Indexed: 12/11/2022] Open
Abstract
Hypoglycemia represents a dark and tormented side of diabetes mellitus therapy. Patients treated with insulin or drug inducing hypoglycemia, consider hypoglycemia as a harmful element, which leads to their resistance and lack of acceptance of the pathology and relative therapies. Severe hypoglycemia, in itself, is a risk for patients and relatives. The possibility to have novel strategies and scientific knowledge concerning hypoglycemia could represent an enormous benefit. Novel available glucagon formulations, even now, allow clinicians to deal with hypoglycemia differently with respect to past years. Novel scientific evidence leads to advances concerning physiopathological mechanisms that regulated glycemic homeostasis. In this review, we will try to show some of the important aspects of this field.
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Affiliation(s)
- Francesca Porcellati
- Department of Medicine and Surgery, Perugia University School of Medicine, Via Gambuli 1, 06126 Perugia, Italy; (F.P.); (A.M.); (M.D.F.); (C.G.F.)
| | - Stefania Di Mauro
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (S.D.M.); (A.S.); (A.F.); (F.P.); (S.P.)
| | - Alessio Mazzieri
- Department of Medicine and Surgery, Perugia University School of Medicine, Via Gambuli 1, 06126 Perugia, Italy; (F.P.); (A.M.); (M.D.F.); (C.G.F.)
| | - Alessandra Scamporrino
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (S.D.M.); (A.S.); (A.F.); (F.P.); (S.P.)
| | - Agnese Filippello
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (S.D.M.); (A.S.); (A.F.); (F.P.); (S.P.)
| | - Michelantonio De Fano
- Department of Medicine and Surgery, Perugia University School of Medicine, Via Gambuli 1, 06126 Perugia, Italy; (F.P.); (A.M.); (M.D.F.); (C.G.F.)
| | - Carmine Giuseppe Fanelli
- Department of Medicine and Surgery, Perugia University School of Medicine, Via Gambuli 1, 06126 Perugia, Italy; (F.P.); (A.M.); (M.D.F.); (C.G.F.)
| | - Francesco Purrello
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (S.D.M.); (A.S.); (A.F.); (F.P.); (S.P.)
| | - Roberta Malaguarnera
- Faculty of Medicine and Surgery, University of Enna “Kore”, 94100 Enna, Italy
- Correspondence: ; Tel.: +39-0935-536577
| | - Salvatore Piro
- Department of Clinical and Experimental Medicine, Internal Medicine, Garibaldi-Nesima Hospital, University of Catania, 95122 Catania, Italy; (S.D.M.); (A.S.); (A.F.); (F.P.); (S.P.)
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Bisgaard Bengtsen M, Møller N. Mini-review: Glucagon responses in type 1 diabetes - a matter of complexity. Physiol Rep 2021; 9:e15009. [PMID: 34405569 PMCID: PMC8371343 DOI: 10.14814/phy2.15009] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 07/29/2021] [Indexed: 12/14/2022] Open
Abstract
In recent years the role of altered alpha cell function and glucagon secretion in type 1 diabetes has attracted scientific attention. It is well established that glucagon responses to hypoglycemia are absent in type 1 diabetes, but more uncertain whether it is intact following other physiological and metabolic stimuli compared with nondiabetic individuals. The aim of this review is to (i) summarize current knowledge on glucagon responses during hypoglycemia in normal physiology and type 1 diabetes, and (ii) review human in vivo studies investigating glucagon responses after other stimuli in individuals with type 1 diabetes and nondiabetic individuals. Available data suggest that in type 1 diabetes the absence of glucagon secretion after hypoglycemia is irreversible. This is a scenario specific to hypoglycemia, since other stimuli, including administration of amino acids, insulin withdrawal, lipopolysaccharide exposure and exercise lead to substantial glucagon responses though attenuated compared to nondiabetic individuals in head-to-head studies. The derailed glucagon secretion is not confined to hypoglycemia as individuals with type 1 diabetes, as opposed to nondiabetic individuals display glucagon hypersecretion after meals, thereby potentially contributing to insulin resistance. The complexity of these phenomena may relate to activation of distinct regulatory pathways controlling glucagon secretion i.e., intra-islet paracrine signaling, direct and autonomic nervous signaling.
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Affiliation(s)
- Mads Bisgaard Bengtsen
- Department of Endocrinology and Internal MedicineAarhus University HospitalAarhusDenmark
- Department of Internal MedicineRegional Hospital HorsensHorsensDenmark
| | - Niels Møller
- Department of Endocrinology and Internal MedicineAarhus University HospitalAarhusDenmark
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Holton KF, Hargrave SL, Davidson TL. Differential Effects of Dietary MSG on Hippocampal Dependent Memory Are Mediated by Diet. Front Neurosci 2019; 13:968. [PMID: 31572118 PMCID: PMC6751330 DOI: 10.3389/fnins.2019.00968] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 08/29/2019] [Indexed: 12/26/2022] Open
Abstract
Introduction Free glutamate is a common dietary flavor enhancer and is also an important excitatory neurotransmitter in the body. A good number of food additives which contain glutamate are found in the Western Diet, and this diet has also been linked to increased risk of cognitive dysfunction. Objective To examine the effects of dietary glutamate on hippocampal and non-hippocampal memory performance, and whether consuming a diet high in fat/sugar could influence any observed associations. Methods Sixty-four adult male Sprague-Dawley rats were trained concurrently on two different discrimination problems: (1) Pavlovian serial feature negative (sFN) discrimination, in which a brief tone stimulus was reinforced with sucrose pellets when it was presented alone (T+ trials) and non-reinforced on trials when it was preceded by the presentation of a brief light (LT− trials); and (2) a simple discrimination (SD) problem in which a white noise (WN+) cue was reinforced with sucrose pellets and a clicker (C-) stimulus was not reinforced. Previous research has shown that sFN, but not SD performance, depends on the functional integrity of the hippocampus. After solving both problems, the rats were assigned to one of four ad libitum-fed diet groups, matched on weight and discrimination performance: (1) high fat, high sugar western-style diet (WD), (2) standard laboratory rodent chow diet (chow), (3) WD + monosodium glutamate (MSG), or (4) chow + MSG. Results After 14 weeks, rats fed WD had higher adiposity than rats fed chow. Consistent with previous findings, rats fed WD exhibited impaired performance on the sFN problem, but not on the SD, relative to rats fed chow. Adding MSG to WD abolished this impairment, whereas rats fed chow + MSG had impaired sFN performance compared to rats fed chow alone. No differences in performance on the SD task were observed. Conclusion This study demonstrates differing effects of dietary glutamate on hippocampal dependent memory function, with MSG impairing hippocampal function in animals receiving chow, while improving hippocampal function in animals receiving a Western-type diet, high in fat and sugar. More research will be needed to explore the cause of these differential effects.
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Affiliation(s)
- Kathleen F Holton
- Nutritional Neuroscience Laboratory, Department of Health Studies, Center for Behavioral Neuroscience, American University, Washington, DC, United States
| | - Sara L Hargrave
- National Cancer Institute, National Institutes of Health, Rockville, MD, United States
| | - Terry L Davidson
- Laboratory for Behavioral and Neural Homeostasis, Department of Psychology, Center for Behavioral Neuroscience, American University, Washington, DC, United States
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Nistor M, Schmidt M, Graul I, Rakers F, Schiffner R. A Systematic Review of Neuroprotective Strategies in the Management of Hypoglycemia. Int J Mol Sci 2019; 20:ijms20030550. [PMID: 30696060 PMCID: PMC6386855 DOI: 10.3390/ijms20030550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 01/18/2019] [Accepted: 01/24/2019] [Indexed: 02/07/2023] Open
Abstract
Severe hypogylcemia has been found to induce cerebral damage. While a number of illnesses can lead to hypoglycemic episodes, antidiabetic medications prescribed for glycemic control are a common cause. Considering the rising prevalence of diabetes mellitus in the population, we investigated neuroprotective strategies during hypoglycemia in the form of a systematic review in adherence to the PRISMA statement. A review protocol was registered in the PROSPERO database. A systematic literature search of PubMed, Web of Science, and CENTRAL was performed in September 2018. Based on a predefined inclusion protocol, results were screened and evaluated by two researchers. Both animal experiments and human studies were included, and their risk of bias was assessed with SYRCLE’s and the Cochrane risk of bias tools, respectively. Of a total of 16,230 results, 145 were assessed in full-text form: 27 articles adhered to the inclusion criteria and were qualitatively analyzed. The retrieved neuroprotective strategies could be categorized into three subsets: (1) Energy substitution, (2) hypoglycemia unawareness, and (3) other neuroprotective strategies. While on a study level, the individual results appeared promising, more research is required to investigate not only specific neuroprotective strategies against hypoglycemic cerebral damage, but also its underlying pathophysiological mechanisms.
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Affiliation(s)
- Marius Nistor
- Department of Neurology, Jena University Hospital - Friedrich Schiller University, Jena 07747, Germany.
| | - Martin Schmidt
- Institute for Biochemistry II, Jena University Hospital - Friedrich Schiller University, Jena 07743, Germany.
| | - Isabel Graul
- Orthopedic Department, Jena University Hospital - Friedrich Schiller University, Campus Eisenberg, Klosterlausnitzer Straße 81, Eisenberg 07607, Germany.
| | - Florian Rakers
- Department of Neurology, Jena University Hospital - Friedrich Schiller University, Jena 07747, Germany.
| | - René Schiffner
- Department of Neurology, Jena University Hospital - Friedrich Schiller University, Jena 07747, Germany.
- Orthopedic Department, Jena University Hospital - Friedrich Schiller University, Campus Eisenberg, Klosterlausnitzer Straße 81, Eisenberg 07607, Germany.
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11
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Rooijackers HMM, Wiegers EC, Tack CJ, van der Graaf M, de Galan BE. Brain glucose metabolism during hypoglycemia in type 1 diabetes: insights from functional and metabolic neuroimaging studies. Cell Mol Life Sci 2016; 73:705-22. [PMID: 26521082 PMCID: PMC4735263 DOI: 10.1007/s00018-015-2079-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 12/30/2022]
Abstract
Hypoglycemia is the most frequent complication of insulin therapy in patients with type 1 diabetes. Since the brain is reliant on circulating glucose as its main source of energy, hypoglycemia poses a threat for normal brain function. Paradoxically, although hypoglycemia commonly induces immediate decline in cognitive function, long-lasting changes in brain structure and cognitive function are uncommon in patients with type 1 diabetes. In fact, recurrent hypoglycemia initiates a process of habituation that suppresses hormonal responses to and impairs awareness of subsequent hypoglycemia, which has been attributed to adaptations in the brain. These observations sparked great scientific interest into the brain's handling of glucose during (recurrent) hypoglycemia. Various neuroimaging techniques have been employed to study brain (glucose) metabolism, including PET, fMRI, MRS and ASL. This review discusses what is currently known about cerebral metabolism during hypoglycemia, and how findings obtained by functional and metabolic neuroimaging techniques contributed to this knowledge.
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Affiliation(s)
- Hanne M M Rooijackers
- Department of Internal Medicine 463, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands.
| | - Evita C Wiegers
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Cees J Tack
- Department of Internal Medicine 463, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
| | - Marinette van der Graaf
- Department of Radiology and Nuclear Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
- Department of Pediatrics, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Bastiaan E de Galan
- Department of Internal Medicine 463, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, The Netherlands
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12
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Salehi M, Woods SC, D’Alessio DA. Gastric bypass alters both glucose-dependent and glucose-independent regulation of islet hormone secretion. Obesity (Silver Spring) 2015; 23:2046-52. [PMID: 26316298 PMCID: PMC4586360 DOI: 10.1002/oby.21186] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Revised: 05/18/2015] [Accepted: 05/21/2015] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Roux-en-Y gastric bypass surgery (GB) is characterized by accentuated but short-lived postprandial elevations of blood glucose and insulin. This profile has been attributed to effects of relative hyperglycemia to directly stimulate β-cells and an augmented incretin effect. An additional glucose-independent stimulation of insulin secretion in GB subjects was hypothesized. METHODS Fifteen subjects with prior GB, six matched obese non surgical controls, and seven lean individuals were recruited. Islet hormones were measured before and after meal ingestion during hyperinsulinemic hypoglycemic clamps to minimize the direct effects of glycemia and glucose-dependent gastrointestinal hormones on insulin secretion. RESULTS The GB subjects had less suppression of fasting β-cell secretion during the insulin clamp compared to controls. In addition, meal-induced insulin secretion increased in the GB subjects but not controls during fixed sub-basal glycemia. In contrast, the glucagon responses to hypoglycemia and meal ingestion were lower in the GB subjects than controls. CONCLUSIONS Among subjects with GB, the response of insulin and glucagon secretion to decreasing blood glucose is blunted, but meal-induced insulin secretion is stimulated even at fixed systemic sub-basal glycemia. These findings indicate that, following GB, islet hormone secretion is altered as a result of factors beyond circulatory glucose levels.
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Affiliation(s)
- Marzieh Salehi
- Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Stephen C. Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati College of Medicine, Cincinnati, OH
| | - David A. D’Alessio
- Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH
- Cincinnati VA Medical Center, Cincinnati, OH
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13
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Abstract
A constant supply of glucose to the brain is critical for normal cerebral metabolism. The dysglycemia of type 1 diabetes (T1D) can affect activity, survival, and function of neural cells. Clinical studies in T1D have shown impairments in brain morphology and function. The most neurotoxic milieu seems to be young age and/or diabetic ketoacidosis at onset, severe hypoglycemia under the age of 6 years followed by chronic hyperglycemia. Adverse cognitive outcomes seem to be associated with poorer mental health outcomes. It is imperative to improve outcomes by investigating the mechanisms of injury so that neuroprotective strategies independent of glycemia can be identified.
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Affiliation(s)
- Fergus J Cameron
- Department of Endocrinology and Diabetes, Royal Children's Hospital, Murdoch Childrens Research Institute, 50 Flemington Road, Parkville, Melbourne 3052, Australia; Department of Paediatrics, University of Melbourne, Melbourne 3010, Australia.
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14
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Desjardins K, Brazeau AS, Strychar I, Rabasa-Lhoret R. Are bedtime nutritional strategies effective in preventing nocturnal hypoglycaemia in patients with type 1 diabetes? Diabetes Obes Metab 2014; 16:577-87. [PMID: 24320159 DOI: 10.1111/dom.12232] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 06/04/2013] [Accepted: 10/25/2013] [Indexed: 11/28/2022]
Abstract
Hypoglycaemia remains the major limiting factor for adequate diabetes control for patients with type 1 diabetes (T1D), especially during the night-time. Although nutritional strategies for nocturnal hypoglycaemia (NH) prevention are regularly suggested in clinical practice, there is no evidence-based recommendation for the usefulness and optimal composition of a bedtime snack. The aim of this narrative review was to analyse the current state of knowledge on nutritional strategies to prevent NH in individuals with T1D. A literature search was conducted, using PubMed and Medline (1946 to 2013); 16 studies were retrieved. Overall, the level of evidence was low. Results indicated that a calibrated bedtime snack based on bedtime blood glucose (BG) level could be effective to reduce NH occurrence for patients treated with human or animal insulin (short-acting combined with lente, ultralente and/or intermediate-acting insulin), but there is no evidence for patients treated with insulin analogues as part of multiple daily injections or insulin pump regimen. Some evidence suggests that including uncooked cornstarch or alanine in the bedtime snack composition could provide some benefits for the prevention of NH. Individualized recommendations of a bedtime snack intake for patients or situations at high risk for NH (long standing diabetes, hypoglycaemia unawareness, prior physical activity, alcohol consumption, bedtime BG close to hypoglycaemia threshold) appear as a prudent recommendation. On the basis of the available evidence, a bedtime snack cannot be recommended systematically but it might be useful if prescribed in an individualized fashion; further research is needed to evaluate these strategies.
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Affiliation(s)
- K Desjardins
- Institut de Recherches Cliniques de Montréal, Montreal, Quebec, Canada; Department of nutrition, Université de Montréal, Montreal, Quebec, Canada
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15
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Graveling AJ, Deary IJ, Frier BM. Acute hypoglycemia impairs executive cognitive function in adults with and without type 1 diabetes. Diabetes Care 2013; 36:3240-6. [PMID: 23780950 PMCID: PMC3781527 DOI: 10.2337/dc13-0194] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Acute hypoglycemia impairs cognitive function in several domains. Executive cognitive function governs organization of thoughts, prioritization of tasks, and time management. This study examined the effect of acute hypoglycemia on executive function in adults with and without diabetes. RESEARCH DESIGN AND METHODS Thirty-two adults with and without type 1 diabetes with no vascular complications or impaired awareness of hypoglycemia were studied. Two hyperinsulinemic glucose clamps were performed at least 2 weeks apart in a single-blind, counterbalanced order, maintaining blood glucose at 4.5 mmol/L (euglycemia) or 2.5 mmol/L (hypoglycemia). Executive functions were assessed with a validated test suite (Delis-Kaplan Executive Function). A general linear model (repeated-measures ANOVA) was used. Glycemic condition (euglycemia or hypoglycemia) was the within-participant factor. Between-participant factors were order of session (euglycemia-hypoglycemia or hypoglycemia-euglycemia), test battery used, and diabetes status (with or without diabetes). RESULTS Compared with euglycemia, executive functions (with one exception) were significantly impaired during hypoglycemia; lower test scores were recorded with more time required for completion. Large Cohen d values (>0.8) suggest that hypoglycemia induces decrements in aspects of executive function with large effect sizes. In some tests, the performance of participants with diabetes was more impaired than those without diabetes. CONCLUSIONS Executive cognitive function, which is necessary to carry out many everyday activities, is impaired during hypoglycemia in adults with and without type 1 diabetes. This important aspect of cognition has not received previous systematic study with respect to hypoglycemia. The effect size is large in terms of both accuracy and speed.
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16
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Inkster B, Frier BM. The effects of acute hypoglycaemia on cognitive function in type 1 diabetes. ACTA ACUST UNITED AC 2012. [DOI: 10.1177/1474651412466273] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Throughout life with type 1 diabetes mellitus people with the condition are exposed to multiple episodes of hypoglycaemia associated with insulin therapy. Hypoglycaemia affects several domains of cognitive function. Studies in non-diabetic adults and in people with type 1 diabetes have shown that almost all domains of cognitive function are impaired to some degree during acute hypoglycaemia, with complex tasks being more greatly affected. The specific cognitive functions of attention and memory are both profoundly impaired during hypoglycaemia. These cognitive processes are fundamental to the performance of many day to day tasks. Their impairment disrupts everyday life and raises safety concerns for the pursuit of activities such as driving. Mood and emotion are also negatively affected by hypoglycaemia, resulting in tense tiredness, while motivation is reduced, and anger may be generated in some individuals. Hypoglycaemia can cause embarrassing social situations, and may lead to chronic anxiety and depression in people with type 1 diabetes. At present few therapeutic measures can modify or ameliorate the effects of hypoglycaemia on cognitive function, so instigation of measures to prevent exposure to hypoglycaemia is of major clinical importance, while preserving good glycaemic control.
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Affiliation(s)
| | - Brian M Frier
- The Queen’s Medical Research Institute, University of Edinburgh, Scotland, UK
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Brand-Miller JC, Griffin HJ, Colagiuri S. The carnivore connection hypothesis: revisited. J Obes 2012; 2012:258624. [PMID: 22235369 PMCID: PMC3253466 DOI: 10.1155/2012/258624] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Accepted: 10/21/2011] [Indexed: 12/26/2022] Open
Abstract
The "Carnivore Connection" hypothesizes that, during human evolution, a scarcity of dietary carbohydrate in diets with low plant : animal subsistence ratios led to insulin resistance providing a survival and reproductive advantage with selection of genes for insulin resistance. The selection pressure was relaxed at the beginning of the Agricultural Revolution when large quantities of cereals first entered human diets. The "Carnivore Connection" explains the high prevalence of intrinsic insulin resistance and type 2 diabetes in populations that transition rapidly from traditional diets with a low-glycemic load, to high-carbohydrate, high-glycemic index diets that characterize modern diets. Selection pressure has been relaxed longest in European populations, explaining a lower prevalence of insulin resistance and type 2 diabetes, despite recent exposure to famine and food scarcity. Increasing obesity and habitual consumption of high-glycemic-load diets worsens insulin resistance and increases the risk of type 2 diabetes in all populations.
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Affiliation(s)
- Jennie C. Brand-Miller
- The Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, The University of Sydney, G89 Medical Foundation Building K25, NSW 2006, Sydney, Australia
- The School of Molecular Bioscience G08, The University of Sydney, Sydney, NSW 2006, Australia
- *Jennie C. Brand-Miller:
| | | | - Stephen Colagiuri
- The Boden Institute of Obesity, Nutrition, Exercise and Eating Disorders, The University of Sydney, G89 Medical Foundation Building K25, NSW 2006, Sydney, Australia
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Vuille-Dit-Bille RN, Ha-Huy R, Stover JF. Changes in plasma phenylalanine, isoleucine, leucine, and valine are associated with significant changes in intracranial pressure and jugular venous oxygen saturation in patients with severe traumatic brain injury. Amino Acids 2011; 43:1287-96. [DOI: 10.1007/s00726-011-1202-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Accepted: 12/09/2011] [Indexed: 01/31/2023]
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Abstract
OBJECTIVE We tested the hypothesis that an increase in insulin per se, i.e., in the absence of zinc, suppresses glucagon secretion during euglycemia and that a decrease in insulin per se stimulates glucagon secretion during hypoglycemia in humans. RESEARCH DESIGN AND METHODS We measured plasma glucagon concentrations in patients with type 1 diabetes infused with the zinc-free insulin glulisine on three occasions. Glulisine was infused with clamped euglycemia (∼95 mg/dl [5.3 mmol/l]) from 0 to 60 min on all three occasions. Then, glulisine was discontinued with clamped euglycemia or with clamped hypoglycemia (∼55 mg/dl [3.0 mmol/l]) or continued with clamped hypoglycemia from 60 to 180 min. RESULTS Plasma glucagon concentrations were suppressed by -13 ± 3, -9 ± 3, and -12 ± 2 pg/ml (-3.7 ± 0.9, -2.6 ± 0.9, and -3.4 ± 0.6 pmol/l), respectively, (all P < 0.01) during zinc-free hyperinsulinemic euglycemia over the first 60 min. Glucagon levels remained suppressed following a decrease in zinc-free insulin with euglycemia (-14 ± 3 pg/ml [-4.0 ± 0.9 pmol/l]) and during sustained hyperinsulinemia with hypoglycemia (-14 ± 2 pg/ml [-4.0 ± 0.6 pmol/l]) but increased to -3 ± 3 pg/ml (-0.9 ± 0.9 pmol/l) (P < 0.01) following a decrease in zinc-free insulin with hypoglycemia over the next 120 min. CONCLUSIONS These data indicate that an increase in insulin per se suppresses glucagon secretion and a decrease in insulin per se, in concert with a low glucose concentration, stimulates glucagon secretion. Thus, they document that insulin is a β-cell secretory product that, in concert with glucose and among other signals, reciprocally regulates α-cell glucagon secretion in humans.
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Affiliation(s)
- Benjamin A. Cooperberg
- From the Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, St. Louis, Missouri
| | - Philip E. Cryer
- From the Division of Endocrinology, Metabolism and Lipid Research, Washington University School of Medicine, St. Louis, Missouri
- Corresponding author: Philip E. Cryer,
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20
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Abstract
This short review outlines the physiology of glucagon in vivo, with an emphasis on its neural control, the author's area of interest. Glucagon is secreted from alpha cells, which are a minority of the pancreatic islet. Anatomically, they are down stream from the majority islet beta cells. Beta-cell secretory products restrain glucagon secretion. Activation of the autonomic nerves, which innervate the islet, increases glucagon secretion. Glucagon is secreted into the portal vein and thus has its major physiologic action at the liver to break down glycogen. Glucagon thereby maintains hepatic glucose production during fasting and increases hepatic glucose production during stress, including the clinically important stress of hypoglycemia. Three different mechanisms proposed to stimulate glucagon secreted during hypoglycemia are discussed: (1) a stimulatory effect of low glucose directly on the alpha cell, (2) withdrawal of an inhibitory effect of adjacent beta cells, and (3) a stimulatory effect of autonomic activation. In type 1 diabetes (T1DM), increased glucagon secretion contributes to the elevated ketones and acidosis present in diabetic ketoacidosis (DKA). It also contributes to the hyperglycemia seen with or without DKA. The glucagon response to insulin-induced hypoglycemia is impaired soon after the development of T1DM. The mediators of this impairment include loss of beta cells and loss of sympathetic nerves from the autoimmune diabetic islet.
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Page KA, Williamson A, Yu N, McNay EC, Dzuira J, McCrimmon RJ, Sherwin RS. Medium-chain fatty acids improve cognitive function in intensively treated type 1 diabetic patients and support in vitro synaptic transmission during acute hypoglycemia. Diabetes 2009; 58:1237-44. [PMID: 19223595 PMCID: PMC2671041 DOI: 10.2337/db08-1557] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVE We examined whether ingestion of medium-chain triglycerides could improve cognition during hypoglycemia in subjects with intensively treated type 1 diabetes and assessed potential underlying mechanisms by testing the effect of beta-hydroxybutyrate and octanoate on rat hippocampal synaptic transmission during exposure to low glucose. RESEARCH DESIGN AND METHODS A total of 11 intensively treated type 1 diabetic subjects participated in stepped hyperinsulinemic- (2 mU x kg(-1) x min(-1)) euglycemic- (glucose approximately 5.5 mmol/l) hypoglycemic (glucose approximately 2.8 mmol/l) clamp studies. During two separate sessions, they randomly received either medium-chain triglycerides or placebo drinks and performed a battery of cognitive tests. In vitro rat hippocampal slice preparations were used to assess the ability of beta-hydroxybutyrate and octanoate to support neuronal activity when glucose levels are reduced. RESULTS Hypoglycemia impaired cognitive performance in tests of verbal memory, digit symbol coding, digit span backwards, and map searching. Ingestion of medium-chain triglycerides reversed these effects. Medium-chain triglycerides also produced higher free fatty acids and beta-hydroxybutyrate levels compared with placebo. However, the increase in catecholamines and symptoms during hypoglycemia was not altered. In hippocampal slices beta-hydroxybutyrate supported synaptic transmission under low-glucose conditions, whereas octanoate could not. Nevertheless, octanoate improved the rate of recovery of synaptic function upon restoration of control glucose concentrations. CONCLUSIONS Medium-chain triglyceride ingestion improves cognition without adversely affecting adrenergic or symptomatic responses to hypoglycemia in intensively treated type 1 diabetic subjects. Medium-chain triglycerides offer the therapeutic advantage of preserving brain function under hypoglycemic conditions without causing deleterious hyperglycemia.
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Affiliation(s)
- Kathleen A Page
- Section of Endocrinology, Yale School of Medicine, New Haven, Connecticut, USA.
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