1
|
Kumaria A, Kirkman MA, Scott RA, Dow GR, Leggate AJ, Macarthur DC, Ingale HA, Smith SJ, Basu S. A Reappraisal of the Pathophysiology of Cushing Ulcer: A Narrative Review. J Neurosurg Anesthesiol 2024; 36:211-217. [PMID: 37188653 DOI: 10.1097/ana.0000000000000918] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 03/21/2023] [Indexed: 05/17/2023]
Abstract
In 1932, Harvey Cushing described peptic ulceration secondary to raised intracranial pressure and attributed this to vagal overactivity, causing excess gastric acid secretion. Cushing ulcer remains a cause of morbidity in patients, albeit one that is preventable. This narrative review evaluates the evidence pertaining to the pathophysiology of neurogenic peptic ulceration. Review of the literature suggests that the pathophysiology of Cushing ulcer may extend beyond vagal mechanisms for several reasons: (1) clinical and experimental studies have shown only a modest increase in gastric acid secretion in head-injured patients; (2) increased vagal tone is found in only a minority of cases of intracranial hypertension, most of which are related to catastrophic, nonsurvivable brain injury; (3) direct stimulation of the vagus nerve does not cause peptic ulceration, and; (4) Cushing ulcer can occur after acute ischemic stroke, but only a minority of strokes are associated with raised intracranial pressure and/or increased vagal tone. The 2005 Nobel Prize in Medicine honored the discovery that bacteria play key roles in the pathogenesis of peptic ulcer disease. Brain injury results in widespread changes in the gut microbiome in addition to gastrointestinal inflammation, including systemic upregulation of proinflammatory cytokines. Alternations in the gut microbiome in patients with severe traumatic brain injury include colonization with commensal flora associated with peptic ulceration. The brain-gut-microbiome axis integrates the central nervous system, the enteric nervous system, and the immune system. Following the review of the literature, we propose a novel hypothesis that neurogenic peptic ulcer may be associated with alterations in the gut microbiome, resulting in gastrointestinal inflammation leading to ulceration.
Collapse
Affiliation(s)
| | | | - Robert A Scott
- NIHR Biomedical Research Centre, Nottingham University Hospitals NHS Trust
- Nottingham Digestive Diseases Centre
| | - Graham R Dow
- Department of Neurosurgery, Queen's Medical Centre
| | | | | | | | - Stuart J Smith
- Department of Neurosurgery, Queen's Medical Centre
- Children's Brain Tumour Research Centre, School of Medicine, University of Nottingham, Nottingham, UK
| | - Surajit Basu
- Department of Neurosurgery, Queen's Medical Centre
| |
Collapse
|
2
|
Tanday N, Tarasov AI, Moffett RC, Flatt PR, Irwin N. Pancreatic islet cell plasticity: Pathogenic or therapeutically exploitable? Diabetes Obes Metab 2024; 26:16-31. [PMID: 37845573 DOI: 10.1111/dom.15300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/07/2023] [Accepted: 09/18/2023] [Indexed: 10/18/2023]
Abstract
The development of pancreatic islet endocrine cells is a tightly regulated process leading to the generation of distinct cell types harbouring different hormones in response to small changes in environmental stimuli. Cell differentiation is driven by transcription factors that are also critical for the maintenance of the mature islet cell phenotype. Alteration of the insulin-secreting β-cell transcription factor set by prolonged metabolic stress, associated with the pathogenesis of diabetes, obesity or pregnancy, results in the loss of β-cell identity through de- or transdifferentiation. Importantly, the glucose-lowering effects of approved and experimental antidiabetic agents, including glucagon-like peptide-1 mimetics, novel peptides and small molecules, have been associated with preventing or reversing β-cell dedifferentiation or promoting the transdifferentiation of non-β-cells towards an insulin-positive β-cell-like phenotype. Therefore, we review the manifestations of islet cell plasticity in various experimental settings and discuss the physiological and therapeutic sides of this phenomenon, focusing on strategies for preventing β-cell loss or generating new β-cells in diabetes. A better understanding of the molecular mechanisms underpinning islet cell plasticity is a prerequisite for more targeted therapies to help prevent β-cell decline in diabetes.
Collapse
Affiliation(s)
- Neil Tanday
- Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland
- Institute of Diabetes and Regeneration Research, Helmholtz Zentrum München, Neuherberg, Germany
| | - Andrei I Tarasov
- Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland
| | - R Charlotte Moffett
- Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland
| | - Peter R Flatt
- Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland
| | - Nigel Irwin
- Diabetes Research Centre, School of Biomedical Sciences, Ulster University, Coleraine, Northern Ireland
| |
Collapse
|
3
|
Maiztegui B, Villagarcía HG, Román CL, Flores LE, Prieto JM, Castro MC, Massa ML, Schinella GR, Francini F. Dietary Supplementation with Yerba Mate ( Ilex paraguariensis) Infusion Increases IRS-1 and PI3K mRNA Levels and Enhances Insulin Sensitivity and Secretion in Rat Pancreatic Islets. PLANTS (BASEL, SWITZERLAND) 2023; 12:2620. [PMID: 37514235 PMCID: PMC10383281 DOI: 10.3390/plants12142620] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/30/2023]
Abstract
"Yerba mate" (YM), an aqueous extract of Ilex paraguariensis, has antioxidant, diuretic, cardio-protective and hypoglycaemic properties. Since its effect on the pancreatic islets remains unclear, we evaluated insulin sensitivity and glucose-stimulated insulin secretion (GSIS) in rats consuming YM or tap water (C) for 21 days. Glucose tolerance, glycemia, triglyceridemia, insulinemia, TBARS and FRAP serum levels were evaluated. GSIS and mRNA levels of insulin signaling pathway and inflammatory markers were measured in isolated pancreatic islets from both groups. In C rats, islets were incubated with YM extract or its phenolic components to measure GSIS. YM improved glucose tolerance, enhanced GSIS, increased FRAP plasma levels and islet mRNA levels of IRS-1 and PI3K (p110), and decreased TBARS plasma levels and islet gene expression of TNF-α and PAI-1. Islets from C rats incubated with 100 µg/mL dry YM extract, 1 µM chlorogenic acid, 0.1 and 1 µM rutin, 1 µM caffeic acid or 1 µM quercetin showed an increase in GSIS. Our results suggest that YM enhances glucose tolerance because of its positive effects on GSIS, oxidative stress rate and insulin sensitivity in rat islets, suggesting that long-term dietary supplementation with YM may improve glucose homeostasis in pre-diabetes or type 2 diabetes.
Collapse
Affiliation(s)
- Bárbara Maiztegui
- CENEXA, Centro de Endocrinología Experimental y Aplicada (UNLP-CONICET La Plata), La Plata 1900, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de la Plata, La Plata 1900, Argentina
| | - Hernán Gonzalo Villagarcía
- CENEXA, Centro de Endocrinología Experimental y Aplicada (UNLP-CONICET La Plata), La Plata 1900, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de la Plata, La Plata 1900, Argentina
| | - Carolina Lisi Román
- CENEXA, Centro de Endocrinología Experimental y Aplicada (UNLP-CONICET La Plata), La Plata 1900, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de la Plata, La Plata 1900, Argentina
| | - Luis Emilio Flores
- CENEXA, Centro de Endocrinología Experimental y Aplicada (UNLP-CONICET La Plata), La Plata 1900, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de la Plata, La Plata 1900, Argentina
| | - José María Prieto
- Centre for Natural Products Discovery, School of Pharmacy and Biomolecular Sciences, Liverpool John Moores University, Byrom Street, Liverpool L3 3AF, UK
| | - María Cecilia Castro
- CENEXA, Centro de Endocrinología Experimental y Aplicada (UNLP-CONICET La Plata), La Plata 1900, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de la Plata, La Plata 1900, Argentina
| | - María Laura Massa
- CENEXA, Centro de Endocrinología Experimental y Aplicada (UNLP-CONICET La Plata), La Plata 1900, Argentina
| | - Guillermo R Schinella
- Facultad de Ciencias Médicas, Universidad Nacional de la Plata, La Plata 1900, Argentina
- Instituto de Ciencias de la Salud, UNAJ-CICPBA, Florencio Varela 1888, Argentina
| | - Flavio Francini
- CENEXA, Centro de Endocrinología Experimental y Aplicada (UNLP-CONICET La Plata), La Plata 1900, Argentina
- Facultad de Ciencias Médicas, Universidad Nacional de la Plata, La Plata 1900, Argentina
| |
Collapse
|
4
|
Ramanadham S, Turk J, Bhatnagar S. Noncanonical Regulation of cAMP-Dependent Insulin Secretion and Its Implications in Type 2 Diabetes. Compr Physiol 2023; 13:5023-5049. [PMID: 37358504 PMCID: PMC10809800 DOI: 10.1002/cphy.c220031] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2023]
Abstract
Impaired glucose tolerance (IGT) and β-cell dysfunction in insulin resistance associated with obesity lead to type 2 diabetes (T2D). Glucose-stimulated insulin secretion (GSIS) from β-cells occurs via a canonical pathway that involves glucose metabolism, ATP generation, inactivation of K ATP channels, plasma membrane depolarization, and increases in cytosolic concentrations of [Ca 2+ ] c . However, optimal insulin secretion requires amplification of GSIS by increases in cyclic adenosine monophosphate (cAMP) signaling. The cAMP effectors protein kinase A (PKA) and exchange factor activated by cyclic-AMP (Epac) regulate membrane depolarization, gene expression, and trafficking and fusion of insulin granules to the plasma membrane for amplifying GSIS. The widely recognized lipid signaling generated within β-cells by the β-isoform of Ca 2+ -independent phospholipase A 2 enzyme (iPLA 2 β) participates in cAMP-stimulated insulin secretion (cSIS). Recent work has identified the role of a G-protein coupled receptor (GPCR) activated signaling by the complement 1q like-3 (C1ql3) secreted protein in inhibiting cSIS. In the IGT state, cSIS is attenuated, and the β-cell function is reduced. Interestingly, while β-cell-specific deletion of iPLA 2 β reduces cAMP-mediated amplification of GSIS, the loss of iPLA 2 β in macrophages (MØ) confers protection against the development of glucose intolerance associated with diet-induced obesity (DIO). In this article, we discuss canonical (glucose and cAMP) and novel noncanonical (iPLA 2 β and C1ql3) pathways and how they may affect β-cell (dys)function in the context of impaired glucose intolerance associated with obesity and T2D. In conclusion, we provide a perspective that in IGT states, targeting noncanonical pathways along with canonical pathways could be a more comprehensive approach for restoring β-cell function in T2D. © 2023 American Physiological Society. Compr Physiol 13:5023-5049, 2023.
Collapse
Affiliation(s)
- Sasanka Ramanadham
- Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham, Alabama, USA
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Alabama, USA
| | - John Turk
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Sushant Bhatnagar
- Comprehensive Diabetes Center, University of Alabama at Birmingham, Alabama, USA
- Department of Medicine, University of Alabama at Birmingham, Alabama, USA
| |
Collapse
|
5
|
Lafferty R, Tanday N, Dubey V, Coulter-Parkhill A, Vishal K, Moffett RC, O'Harte F, Flatt PR, Irwin N. The glucagon receptor antagonist desHis 1Pro 4Glu 9-glucagon(Lys 12PAL) alters alpha-cell turnover and lineage in mice, but does not cause alpha-cell hyperplasia. Mol Cell Endocrinol 2023; 570:111932. [PMID: 37080378 DOI: 10.1016/j.mce.2023.111932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Revised: 02/24/2023] [Accepted: 04/16/2023] [Indexed: 04/22/2023]
Abstract
OBJECTIVE Glucagon receptor (GCGR) antagonism elicits antihyperglycemic effects in rodents and humans. The present study investigates whether the well characterised peptide-based GCGR antagonist, desHis1Pro4Glu9-glucagon (Lys12PAL), alters alpha-cell turnover or identity in mice. METHODS Multiple low-dose streptozotocin (STZ) treated (50 mg/kg bw, 5 days) transgenic GluCreERT2;ROSA26-eYFP mice were employed. STZ mice received twice daily administration of saline vehicle or desHis1Pro4Glu9-glucagon (Lys12PAL), at low- or high-dose (25 and 100 nmol/kg, respectively) for 11 days. RESULTS No GCGR antagonist induced changes in food or fluid intake, body weight or glucose homeostasis were observed. As expected, STZ dramatically reduced (P < 0.001) islet numbers and increased (P < 0.01) alpha-to beta-cell ratio, which was linked to elevated (P < 0.05) levels of beta-cell apoptosis. Whilst treatment with desHis1Pro4Glu9-glucagon (Lys12PAL) decreased (P < 0.05-P < 0.001) alpha- and beta-cell areas, it also helped restore the classic rodent islet alpha-cell mantle in STZ mice. Interestingly, low-dose desHis1Pro4Glu9-glucagon (Lys12PAL) increased (P < 0.05) alpha-cell apoptosis rates whilst high dose decreased (p < 0.05) this parameter. This difference reflects substantially increased (P < 0.001) alpha-to beta-cell transdifferentiation following high dose desHis1Pro4Glu9-glucagon (Lys12PAL) treatment, which was not fully manifest with low-dose therapy. CONCLUSIONS Taken together, the present study indicates that peptidic GCGR antagonists can positively influence alpha-cell turnover and lineage in identity in multiple low-dose STZ mice, but that such effects are dose-related.
Collapse
Affiliation(s)
- Ryan Lafferty
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Neil Tanday
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Vaibhav Dubey
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | | | - Karthick Vishal
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | | | - Finbarr O'Harte
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Centre for Diabetes, Ulster University, Coleraine, Northern Ireland, UK.
| |
Collapse
|
6
|
Targher G, Mantovani A, Byrne CD. Mechanisms and possible hepatoprotective effects of glucagon-like peptide-1 receptor agonists and other incretin receptor agonists in non-alcoholic fatty liver disease. Lancet Gastroenterol Hepatol 2023; 8:179-191. [PMID: 36620987 DOI: 10.1016/s2468-1253(22)00338-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/22/2022] [Accepted: 09/29/2022] [Indexed: 01/07/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretins that stimulate insulin secretion from pancreatic β cells in response to food ingestion. Modified GLP-1 and GIP peptides are potent agonists for their incretin receptors, and some evidence shows that the dual GLP-1 and GIP receptor agonist tirzepatide is effective in promoting marked weight loss. GLP-1 receptor agonists signal in the CNS to suppress appetite, increase satiety, and thereby decrease calorie intake, but many other effects of incretin signalling have been recognised that are relevant to the treatment of non-alcoholic fatty liver disease (NAFLD). This Review provides an overview of the literature supporting the notion that endogenous incretins and incretin-receptor agonist treatments are important not only for decreasing risk of developing NAFLD, but also for treating NAFLD and NAFLD-related complications. We discuss incretin signalling and related incretin-receptor agonist treatments, mechanisms in key relevant tissues affecting liver disease, and clinical data from randomised controlled trials. Finally, we present future perspectives in this rapidly developing field of research and clinical medicine.
Collapse
Affiliation(s)
- Giovanni Targher
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Azienda Ospedaliera Universitaria Integrata of Verona, Verona, Italy.
| | - Alessandro Mantovani
- Section of Endocrinology, Diabetes and Metabolism, Department of Medicine, University and Azienda Ospedaliera Universitaria Integrata of Verona, Verona, Italy
| | - Christopher D Byrne
- Nutrition and Metabolism, Faculty of Medicine, University of Southampton, UK; Southampton National Institute for Health Research Biomedical Research Centre, University Hospital Southampton, Southampton General Hospital, Southampton, UK
| |
Collapse
|
7
|
Husic-Selimovic A, Jahic R, Kurtovic A, Custovic N, Fajkic A. Diagnostic Potential of Ratio Between Creatine Kinase and Amylase in Acute Pancreatitis. Mater Sociomed 2023; 35:280-284. [PMID: 38380277 PMCID: PMC10875939 DOI: 10.5455/msm.2023.35.280-284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Accepted: 12/15/2023] [Indexed: 02/22/2024] Open
Abstract
Background Acute pancreatitis (AP) is an acute inflammatory illness of the pancreas representing a true question in diagnostic process. Laboratory markers of the hepatobiliary tract such as liver transaminases with pancreatic enzymes give a true hint of a hidden diagnosis together with urea, creatinine and creatine kinase (CK). Objective This clinical study aims to show whether there is any correlation between alpha-amylase and CK or their ratio examining hospitalized patients with AP diagnosis. Methods From total number of 99 patients with a clinical picture of AP, 71 patients in this retrospective analysis (including both genders) were included according to the presence of two biochemical markers in collected laboratory analysis at admission and 72 hours later on a laboratory check-up: CK and alpha-amylase. Results The median CK value of AP cases was 92 (41.75 - 207.25) in the acute period and 73 (37 - 159) after 72h staying in the hospital without statistical significant (p=0.521; p<0.05). However, there was a statistically significant correlation between the parameters of CK at admission and creatine kinase after 72h staying in the hospital. The median value of CK/Amylase ratio in the acute period was 0.168 (0.069 - 0.532) and 0.386 (0.12 - 1.12) after 72 hours of staying in the hospital. There was a statistically significant difference between values of CK/amylase ratio in these two groups (p=0.000; p<0.01). Conclusion In conclusion, a connection between CK and alpha-amylase needs to be elucidated in further studies and its existence must be researched both in physiological and pathophysiological conditions, and it is two-way and very complex. This study helped us obtain significant information about the perspective of AP in the potential relation to other non-standard laboratory markers for some diseases.
Collapse
Affiliation(s)
| | - Rijad Jahic
- General Hospital Prim. Dr. Abdulah Nakas Sarajevo, Bosnia and Herzegovina
| | - Avdo Kurtovic
- University Clinical Center Tuzla, Bosnia and Herzegovina
| | - Nerma Custovic
- University Clinical Center Sarajevo, Bosnia and Herzegovina
| | - Almir Fajkic
- Faculty of Medicine, University of Sarajevo, Bosnia and Herzegovina
| |
Collapse
|
8
|
Tanday N, Flatt PR, Irwin N. Amplifying the antidiabetic actions of glucagon-like peptide-1: Potential benefits of new adjunct therapies. Diabet Med 2021; 38:e14699. [PMID: 34562330 DOI: 10.1111/dme.14699] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Accepted: 09/23/2021] [Indexed: 12/12/2022]
Abstract
Clinically approved for the treatment of diabetes and obesity, glucagon-like peptide-1 (GLP-1) receptor agonists display prominent glucose- and weight-lowering effects as well as positive cardioprotective and neuroprotective actions. Despite these benefits, bariatric surgery remains superior in producing robust and sustained weight loss alongside improvements in metabolic control with possible diabetes remission. The current review considers the potential for adjunct therapies to augment the therapeutic actions of GLP-1 receptor agonists. In this regard, several gut-derived hormones also, modulated by bariatric surgery, display additive properties when combined with GLP-1 receptor agonists in both preclinical and clinical studies. In addition, glucocorticoids and oestrogen have shown promise in augmenting the biological actions of GLP-1 in animal models. Additionally, GLP-1 efficacy can also be enhanced by use of compounds that prolong GLP-1 receptor coupling to potentiate downstream receptor signalling. Taken together, therapies that activate GLP-1 receptor signalling, in combination with various other cell signalling pathways, show potential for treating type 2 diabetes and obesity with superiority over GLP-1 receptor agonist therapy alone.
Collapse
Affiliation(s)
- Neil Tanday
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Peter R Flatt
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Diabetes Research Group, School of Biomedical Sciences, Ulster University, Coleraine, UK
| |
Collapse
|
9
|
Lafferty RA, Flatt PR, Irwin N. Established and emerging roles peptide YY (PYY) and exploitation in obesity-diabetes. Curr Opin Endocrinol Diabetes Obes 2021; 28:253-261. [PMID: 33395088 DOI: 10.1097/med.0000000000000612] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF REVIEW The antiobesity effects of activation of hypothalamic neuropeptide Y2 receptors (NPYR2) by the gut-derived hormone, peptide YY (PYY), are established. However, more recent insight into the biology of PYY has demonstrated remarkable benefits of sustained activation of pancreatic beta-cell NPYR1, that promises to open a new therapeutic avenue in diabetes. RECENT FINDINGS The therapeutic applicability of NPYR2 agonists for obesity has been considered for many years. An alternative pathway for the clinical realisation of PYY-based drugs could be related to the development of NPYR1 agonists for treatment of diabetes. Thus, although stimulation of NPYR1 on pancreatic beta-cells has immediate insulinostatic effects, prolonged activation of these receptors leads to well defined beta-cell protective effects, with obvious positive implications for the treatment of diabetes. In this regard, NPYR1-specific, long-acting enzyme resistant PYY analogues, have been recently developed with encouraging preclinical effects observed on pancreatic islet architecture in diabetes. In agreement, the benefits of certain types of bariatric surgeries on beta-cell function and responsiveness have also been linked to elevated PYY secretion and NPY1 receptor activation. SUMMARY Enzymatically stable forms of PYY, that selectively activate NPYR1, may have significant potential for preservation of beta-cell mass and the treatment of diabetes.
Collapse
Affiliation(s)
- Ryan A Lafferty
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | | | | |
Collapse
|
10
|
A Practical Guide to Rodent Islet Isolation and Assessment Revisited. Biol Proced Online 2021; 23:7. [PMID: 33641671 PMCID: PMC7919091 DOI: 10.1186/s12575-021-00143-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 01/26/2021] [Indexed: 02/06/2023] Open
Abstract
Insufficient insulin secretion is a key component of both type 1 and type 2 diabetes. Since insulin is released by the islets of Langerhans, obtaining viable and functional islets is critical for research and transplantation. The effective and efficient isolation of these small islands of endocrine cells from the sea of exocrine tissue that is the rest of the pancreas is not necessarily simple or quick. Choosing and administering the digestive enzyme, separation of the islets from acinar tissue, and culture of islets are all things that must be considered. The purpose of this review is to provide a history of the development of islet isolation procedures and to serve as a practical guide to rodent islet research for newcomers to islet biology. We discuss key elements of mouse islet isolation including choosing collagenase, the digestion process, purification of islets using a density gradient, and islet culture conditions. In addition, this paper reviews techniques for assessing islet viability and function such as visual assessment, glucose-stimulated insulin secretion and intracellular calcium measurements. A detailed protocol is provided that describes a common method our laboratory uses to obtain viable and functional mouse islets for in vitro study. This review thus provides a strong foundation for successful procurement and purification of high-quality mouse islets for research purposes.
Collapse
|
11
|
Mohan S, McCloskey AG, McKillop AM, Flatt PR, Irwin N, Moffett RC. Development and characterisation of novel, enzymatically stable oxytocin analogues with beneficial antidiabetic effects in high fat fed mice. Biochim Biophys Acta Gen Subj 2020; 1865:129811. [PMID: 33309687 DOI: 10.1016/j.bbagen.2020.129811] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND There is growing evidence to support beneficial effects of the hypothalamic synthesised hormone, oxytocin, on metabolism. However, the biological half-life of oxytocin is short and receptor activation profile unspecific. METHODS We have characterised peptide-based oxytocin analogues with structural modifications aimed at improving half-life and receptor specificity. Following extensive in vitro and in vivo characterisation, antidiabetic efficacy of lead peptides was examined in high fat fed (HFF) mice. RESULTS Following assessment of stability against enzymatic degradation, insulin secretory activity, receptor activation profile and in vivo bioactivity, analogues 2 N (Ac-C ˂YIQNC >PLG-NH2) and D7R ((d-C)YIQNCYLG-NH2) were selected as lead peptides. Twice daily injection of either peptide for 22 days reduced body weight, energy intake, plasma glucose and insulin and pancreatic glucagon content in HFF mice. In addition, both peptides reduced total- and LDL-cholesterol, with concomitant elevations of HDL-cholesterol, and D7R also decreased triglyceride levels. The two oxytocin analogues improved glucose tolerance and insulin responses to intraperitoneal, and particularly oral, glucose challenge on day 22. Both oxytocin analogues enhanced insulin sensitivity, reduced HOMA-IR and increased bone mineral density. In terms of pancreatic islet histology, D7R reversed high fat feeding induced elevations of islet and beta cell areas, which was associated with reductions in beta cell apoptosis. Islet insulin secretory responsiveness was improved by 2 N, and especially D7R, treatment. CONCLUSION Novel, enzymatically stable oxytocin analogues exert beneficial antidiabetic effects in HFF mice. GENERAL SIGNIFICANCE These observations emphasise the, yet untapped, therapeutic potential of long-acting oxytocin-based agents for obesity and type 2 diabetes.
Collapse
Affiliation(s)
- Shruti Mohan
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - Andrew G McCloskey
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - Aine M McKillop
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - Peter R Flatt
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- Diabetes Research Group, Ulster University, Coleraine, Northern Ireland, UK.
| | | |
Collapse
|