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Dubey V, Tanday N, Irwin N, Tarasov AI, Flatt PR, Moffett RC. Cafeteria diet compromises natural adaptations of islet cell transdifferentiation and turnover in pregnancy. Diabet Med 2024:e15434. [PMID: 39255356 DOI: 10.1111/dme.15434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 08/20/2024] [Accepted: 08/27/2024] [Indexed: 09/12/2024]
Abstract
BACKGROUND Pancreatic islet β-cell mass expands during pregnancy, but underlying mechanisms are not fully understood. This study examines the impact of pregnancy and cafeteria diet on islet morphology, associated cellular proliferation/apoptosis rates as well as β-cell lineage. METHODS Non-pregnant and pregnant Ins1Cre/+;Rosa26-eYFP transgenic mice were maintained on either normal or high-fat cafeteria diet, with pancreatic tissue obtained at 18 days gestation. Immunohistochemical changes in islet morphology, β-/α-cell proliferation and apoptosis, as well as islet cell identity, neogenesis and ductal cell transdifferentiation were assessed. RESULTS Pregnant normal diet mice displayed an increase in body weight and glycaemia. Cafeteria feeding attenuated this weight gain while causing overt hyperglycaemia. Pregnant mice maintained on a normal diet exhibited typical expansion in islet and β-cell area, owing to increased β-cell proliferation and survival as well as ductal to β-cell transdifferentiation and β-cell neogenesis, alongside decreased β-cell dedifferentiation. Such pregnancy-induced islet adaptations were severely restricted by cafeteria diet. Accordingly, islets from these mice displayed high levels of β-cell apoptosis and dedifferentiation, together with diminished β-cell proliferation and lack of pregnancy-induced β-cell neogenesis and transdifferentiation, entirely opposing islet cell modifications observed in pregnant mice maintained on a normal diet. CONCLUSION Augmentation of β-cell mass during gestation arises through various mechanisms that include proliferation and survival of existing β-cells, transdifferentiation of ductal cells as well as β-cell neogenesis. Remarkably, cafeteria feeding almost entirely annuls pregnancy-induced islet adaptations, which may contribute to the development of gestational diabetes in the setting of dietary provoked metabolic stress.
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Affiliation(s)
- Vaibhav Dubey
- Centre for Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Neil Tanday
- Centre for Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Centre for Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Andrei I Tarasov
- Centre for Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Centre for Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
| | - R Charlotte Moffett
- Centre for Diabetes, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland, UK
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2
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Ruiz-Otero N, Tessem JS, Banerjee RR. Pancreatic islet adaptation in pregnancy and postpartum. Trends Endocrinol Metab 2024; 35:834-847. [PMID: 38697900 DOI: 10.1016/j.tem.2024.04.007] [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: 02/12/2024] [Revised: 04/02/2024] [Accepted: 04/08/2024] [Indexed: 05/05/2024]
Abstract
Pancreatic islets, particularly insulin-producing β-cells, are central regulators of glucose homeostasis capable of responding to a variety of metabolic stressors. Pregnancy is a unique physiological stressor, necessitating the islets to adapt to the complex interplay of maternal and fetal-placental factors influencing the metabolic milieu. In this review we highlight studies defining gestational adaptation mechanisms within maternal islets and emerging studies revealing islet adaptations during the early postpartum and lactation periods. These include adaptations in both β and in 'non-β' islet cells. We also discuss insights into how gestational and postpartum adaptation may inform pregnancy-specific and general mechanisms of islet responses to metabolic stress and contribute to investigation of gestational diabetes.
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Affiliation(s)
- Nelmari Ruiz-Otero
- Division of Endocrinology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Jeffery S Tessem
- Department of Nutrition, Dietetics and Food Science, Brigham Young University, Provo, UT 84601, USA
| | - Ronadip R Banerjee
- Division of Endocrinology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA.
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3
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Harding JE, Alsweiler JM, Edwards TE, McKinlay CJD. Neonatal hypoglycaemia. BMJ MEDICINE 2024; 3:e000544. [PMID: 38618170 PMCID: PMC11015200 DOI: 10.1136/bmjmed-2023-000544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 03/04/2024] [Indexed: 04/16/2024]
Abstract
Low blood concentrations of glucose (hypoglycaemia) soon after birth are common because of the delayed metabolic transition from maternal to endogenous neonatal sources of glucose. Because glucose is the main energy source for the brain, severe hypoglycaemia can cause neuroglycopenia (inadequate supply of glucose to the brain) and, if severe, permanent brain injury. Routine screening of infants at risk and treatment when hypoglycaemia is detected are therefore widely recommended. Robust evidence to support most aspects of management is lacking, however, including the appropriate threshold for diagnosis and optimal monitoring. Treatment is usually initially more feeding, with buccal dextrose gel, followed by intravenous dextrose. In infants at risk, developmental outcomes after mild hypoglycaemia seem to be worse than in those who do not develop hypoglycaemia, but the reasons for these observations are uncertain. Here, the current understanding of the pathophysiology of neonatal hypoglycaemia and recent evidence regarding its diagnosis, management, and outcomes are reviewed. Recommendations are made for further research priorities.
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Affiliation(s)
- Jane E Harding
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Jane M Alsweiler
- Department of Paediatrics: Child and Youth Health, University of Auckland, Auckland, New Zealand
- Te Whatu Ora Health New Zealand, Te Toka Tumai, Auckland, New Zealand
| | - Taygen E Edwards
- Liggins Institute, University of Auckland, Auckland, New Zealand
| | - Chris JD McKinlay
- Department of Paediatrics: Child and Youth Health, University of Auckland, Auckland, New Zealand
- Te Whatu Ora Health New Zealand, Counties Manukau, Auckland, New Zealand
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4
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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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5
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Usman TO, Chhetri G, Yeh H, Dong HH. Beta-cell compensation and gestational diabetes. J Biol Chem 2023; 299:105405. [PMID: 38229396 PMCID: PMC10694657 DOI: 10.1016/j.jbc.2023.105405] [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: 08/28/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 01/18/2024] Open
Abstract
Gestational diabetes mellitus (GDM) is characterized by glucose intolerance in pregnant women without a previous diagnosis of diabetes. While the etiology of GDM remains elusive, the close association of GDM with increased maternal adiposity and advanced gestational age implicates insulin resistance as a culpable factor for the pathogenesis of GDM. Pregnancy is accompanied by the physiological induction of insulin resistance in the mother secondary to maternal weight gain. This effect serves to spare blood glucose for the fetus. To overcome insulin resistance, maternal β-cells are conditioned to release more insulin into the blood. Such an adaptive response, termed β-cell compensation, is essential for maintaining normal maternal metabolism. β-cell compensation culminates in the expansion of β-cell mass and augmentation of β-cell function, accounting for increased insulin synthesis and secretion. As a result, a vast majority of mothers are protected from developing GDM during pregnancy. In at-risk pregnant women, β-cells fail to compensate for maternal insulin resistance, contributing to insulin insufficiency and GDM. However, gestational β-cell compensation ensues in early pregnancy, prior to the establishment of insulin resistance in late pregnancy. How β-cells compensate for pregnancy and what causes β-cell failure in GDM are subjects of investigation. In this mini-review, we will provide clinical and preclinical evidence that β-cell compensation is pivotal for overriding maternal insulin resistance to protect against GDM. We will highlight key molecules whose functions are critical for integrating gestational hormones to β-cell compensation for pregnancy. We will provide mechanistic insights into β-cell decompensation in the etiology of GDM.
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Affiliation(s)
- Taofeek O Usman
- Division of Endocrinology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Goma Chhetri
- Division of Endocrinology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Hsuan Yeh
- Division of Endocrinology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - H Henry Dong
- Division of Endocrinology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
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Chung JY, Ma Y, Zhang D, Bickerton HH, Stokes E, Patel SB, Tse HM, Feduska J, Welner RS, Banerjee RR. Pancreatic islet cell type-specific transcriptomic changes during pregnancy and postpartum. iScience 2023; 26:106439. [PMID: 37020962 PMCID: PMC10068570 DOI: 10.1016/j.isci.2023.106439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/11/2023] [Accepted: 03/14/2023] [Indexed: 03/19/2023] Open
Abstract
Pancreatic β-cell mass expands during pregnancy and regresses in the postpartum period in conjunction with dynamic metabolic demands on maternal glucose homeostasis. To understand transcriptional changes driving these adaptations in β-cells and other islet cell types, we performed single-cell RNA sequencing on islets from virgin, late gestation, and early postpartum mice. We identified transcriptional signatures unique to gestation and the postpartum in β-cells, including induction of the AP-1 transcription factor subunits and other genes involved in the immediate-early response (IEGs). In addition, we found pregnancy and postpartum-induced changes differed within each endocrine cell type, and in endothelial cells and antigen-presenting cells within islets. Together, our data reveal insights into cell type-specific transcriptional changes responsible for adaptations by islet cells to pregnancy and their resolution postpartum.
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Affiliation(s)
- Jin-Yong Chung
- Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
| | - Yongjie Ma
- Department of Pharmacology, the University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Dingguo Zhang
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, The University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Hayden H. Bickerton
- Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, The University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Eric Stokes
- Department of Pharmacology, University of Colorado Denver/Anschutz, Aurora, CO 80045, USA
| | - Sweta B. Patel
- Division of Hematology and Oncology, Department of Medicine, The University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Hubert M. Tse
- Department of Microbiology, the University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Joseph Feduska
- Department of Microbiology, the University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Rob S. Welner
- Division of Hematology and Oncology, Department of Medicine, The University of Alabama at Birmingham School of Medicine, Birmingham, AL 35294, USA
| | - Ronadip R. Banerjee
- Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21224, USA
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Qiao L, Saget S, Lu C, Zang T, Dzyuba B, Hay WW, Shao J. The Essential Role of Pancreatic α-Cells in Maternal Metabolic Adaptation to Pregnancy. Diabetes 2022; 71:978-988. [PMID: 35147704 PMCID: PMC9044124 DOI: 10.2337/db21-0923] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022]
Abstract
Pancreatic α-cells are important in maintaining metabolic homeostasis, but their role in regulating maternal metabolic adaptations to pregnancy has not been studied. The objective of this study was to determine whether pancreatic α-cells respond to pregnancy and their contribution to maternal metabolic adaptation. With use of C57BL/6 mice, the findings of our study showed that pregnancy induced a significant increase of α-cell mass by promoting α-cell proliferation that was associated with a transitory increase of maternal serum glucagon concentration in early pregnancy. Maternal pancreatic GLP-1 content also was significantly increased during pregnancy. Using the inducible Cre/loxp technique, we ablated the α-cells (α-null) before and during pregnancy while maintaining enteroendocrine L-cells and serum GLP-1 in the normal range. In contrast to an improved glucose tolerance test (GTT) before pregnancy, significantly impaired GTT and remarkably higher serum glucose concentrations in the fed state were observed in α-null dams. Glucagon receptor antagonism treatment, however, did not affect measures of maternal glucose metabolism, indicating a dispensable role of glucagon receptor signaling in maternal glucose homeostasis. However, the GLP-1 receptor agonist improved insulin production and glucose metabolism of α-null dams. Furthermore, GLP-1 receptor antagonist Exendin (9-39) attenuated pregnancy-enhanced insulin secretion and GLP-1 restored glucose-induced insulin secretion of cultured islets from α-null dams. Together, these results demonstrate that α-cells play an essential role in controlling maternal metabolic adaptation to pregnancy by enhancing insulin secretion.
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Affiliation(s)
- Liping Qiao
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Sarah Saget
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Cindy Lu
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Tianyi Zang
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Brianna Dzyuba
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | | | - Jianhua Shao
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
- Corresponding author: Jianhua Shao,
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8
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Zhang Z, Piro AL, Dai FF, Wheeler MB. Adaptive Changes in Glucose Homeostasis and Islet Function During Pregnancy: A Targeted Metabolomics Study in Mice. Front Endocrinol (Lausanne) 2022; 13:852149. [PMID: 35600586 PMCID: PMC9116578 DOI: 10.3389/fendo.2022.852149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 03/14/2022] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE Pregnancy is a dynamic state involving multiple metabolic adaptions in various tissues including the endocrine pancreas. However, a detailed characterization of the maternal islet metabolome in relation to islet function and the ambient circulating metabolome during pregnancy has not been established. METHODS A timed-pregnancy mouse model was studied, and age-matched non-pregnant mice were used as controls. Targeted metabolomics was applied to fasting plasma and purified islets during each trimester of pregnancy. Glucose homeostasis and islet function was assessed. Bioinformatic analyses were performed to reveal the metabolic adaptive changes in plasma and islets, and to identify key metabolic pathways associated with pregnancy. RESULTS Fasting glucose and insulin were found to be significantly lower in pregnant mice compared to non-pregnant controls, throughout the gestational period. Additionally, pregnant mice had superior glucose excursions and greater insulin response to an oral glucose tolerance test. Interestingly, both alpha and beta cell proliferation were significantly enhanced in early to mid-pregnancy, leading to significantly increased islet size seen in mid to late gestation. When comparing the plasma metabolome of pregnant and non-pregnant mice, phospholipid and fatty acid metabolism pathways were found to be upregulated throughout pregnancy, whereas amino acid metabolism initially decreased in early through mid pregnancy, but then increased in late pregnancy. Conversely, in islets, amino acid metabolism was consistently enriched throughout pregnancy, with glycerophospholid and fatty acid metabolism was only upregulated in late pregnancy. Specific amino acids (glutamate, valine) and lipids (acyl-alkyl-PC, diacyl-PC, and sphingomyelin) were found to be significantly differentially expressed in islets of the pregnant mice compared to controls, which was possibly linked to enhanced insulin secretion and islet proliferation. CONCLUSION Beta cell proliferation and function are elevated during pregnancy, and this is coupled to the enrichment of islet metabolites and metabolic pathways primarily associated with amino acid and glycerophospholipid metabolism. This study provides insight into metabolic adaptive changes in glucose homeostasis and islet function seen during pregnancy, which will provide a molecular rationale to further explore the regulation of maternal metabolism to avoid the onset of pregnancy disorders, including gestational diabetes.
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Affiliation(s)
- Ziyi Zhang
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Department of Endocrinology, Sir Run Run Shaw Hospital, Zhejiang University, Hangzhou, China
| | - Anthony L. Piro
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Feihan F. Dai
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- *Correspondence: Feihan F. Dai, ; Michael B. Wheeler,
| | - Michael B. Wheeler
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Metabolism Research Group, Division of Advanced Diagnostics, Toronto General Hospital Research Institute, Toronto, ON, Canada
- *Correspondence: Feihan F. Dai, ; Michael B. Wheeler,
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Acetone Ingestion Mimics a Fasting State to Improve Glucose Tolerance in a Mouse Model of Gestational Hyperglycemia. Int J Mol Sci 2021; 22:ijms222312914. [PMID: 34884717 PMCID: PMC8657850 DOI: 10.3390/ijms222312914] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 11/23/2021] [Accepted: 11/27/2021] [Indexed: 11/16/2022] Open
Abstract
Gestational diabetes mellitus results, in part, from a sub-optimal β-cell mass (BCM) during pregnancy. Artemisinins were reported to increase BCM in models of diabetes by α- to β-cell conversion leading to enhanced glucose tolerance. We used a mouse model of gestational glucose intolerance to compare the effects of an artemisinin (artesunate) on glycemia of pregnant mice with vehicle treatment (acetone) or no treatment. Animals were treated daily from gestational days (GD) 0.5 to 6.5. An intraperitoneal glucose tolerance test was performed prior to euthanasia at GD18.5 or post-partum. Glucose tolerance was significantly improved in both pregnant and non-pregnant mice with both artesunate and vehicle-alone treatment, suggesting the outcome was primarily due to the acetone vehicle. In non-pregnant, acetone-treated animals, improved glucose tolerance was associated with a higher BCM and a significant increase in bihormonal insulin and glucagon-containing pancreatic islet cells, suggesting α- to β-cell conversion. BCM did not differ with treatment during pregnancy or post-partum. However, placental weight was higher in acetone-treated animals and was associated with an upregulation of apelinergic genes. Acetone-treated animals had reduced weight gain during treatment despite comparable food consumption to non-treated mice, suggesting transient effects on nutrient uptake. The mean duodenal and ileum villus height was reduced following exposure to acetone. We conclude that acetone treatment may mimic transient fasting, resulting in a subsequent improvement in glucose tolerance during pregnancy.
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Strutt B, Szlapinski S, Gnaneswaran T, Donegan S, Hill J, Bennett J, Hill DJ. Ontology of the apelinergic system in mouse pancreas during pregnancy and relationship with β-cell mass. Sci Rep 2021; 11:15475. [PMID: 34326390 PMCID: PMC8322410 DOI: 10.1038/s41598-021-94725-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 07/15/2021] [Indexed: 02/07/2023] Open
Abstract
The apelin receptor (Aplnr) and its ligands, Apelin and Apela, contribute to metabolic control. The insulin resistance associated with pregnancy is accommodated by an expansion of pancreatic β-cell mass (BCM) and increased insulin secretion, involving the proliferation of insulin-expressing, glucose transporter 2-low (Ins+Glut2LO) progenitor cells. We examined changes in the apelinergic system during normal mouse pregnancy and in pregnancies complicated by glucose intolerance with reduced BCM. Expression of Aplnr, Apelin and Apela was quantified in Ins+Glut2LO cells isolated from mouse pancreata and found to be significantly higher than in mature β-cells by DNA microarray and qPCR. Apelin was localized to most β-cells by immunohistochemistry although Aplnr was predominantly associated with Ins+Glut2LO cells. Aplnr-staining cells increased three- to four-fold during pregnancy being maximal at gestational days (GD) 9-12 but were significantly reduced in glucose intolerant mice. Apelin-13 increased β-cell proliferation in isolated mouse islets and INS1E cells, but not glucose-stimulated insulin secretion. Glucose intolerant pregnant mice had significantly elevated serum Apelin levels at GD 9 associated with an increased presence of placental IL-6. Placental expression of the apelinergic axis remained unaltered, however. Results show that the apelinergic system is highly expressed in pancreatic β-cell progenitors and may contribute to β-cell proliferation in pregnancy.
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Affiliation(s)
- Brenda Strutt
- Lawson Health Research Institute, St Joseph Health Care, 268 Grosvenor St, London, ON, N6A 4V2, Canada
| | - Sandra Szlapinski
- Lawson Health Research Institute, St Joseph Health Care, 268 Grosvenor St, London, ON, N6A 4V2, Canada
- Department of Physiology and Pharmacology, Western University, London, ON, N6A 3K7, Canada
| | - Thineesha Gnaneswaran
- Department of Physiology and Pharmacology, Western University, London, ON, N6A 3K7, Canada
| | - Sarah Donegan
- Department of Physiology and Pharmacology, Western University, London, ON, N6A 3K7, Canada
| | - Jessica Hill
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, EX2 5DW, UK
| | - Jamie Bennett
- Lawson Health Research Institute, St Joseph Health Care, 268 Grosvenor St, London, ON, N6A 4V2, Canada
- Life Sciences Program, School of Interdisciplinary Science, McMaster University, Hamilton, ON, L8S 4LD, Canada
| | - David J Hill
- Lawson Health Research Institute, St Joseph Health Care, 268 Grosvenor St, London, ON, N6A 4V2, Canada.
- Department of Physiology and Pharmacology, Western University, London, ON, N6A 3K7, Canada.
- Departments of Medicine and Paediatrics, Western University, London, ON, N6A 3K7, Canada.
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