1
|
Bettadapura S, Dowling K, Jablon K, Al-Humadi AW, le Roux CW. Changes in food preferences and ingestive behaviors after glucagon-like peptide-1 analog treatment: techniques and opportunities. Int J Obes (Lond) 2024:10.1038/s41366-024-01500-y. [PMID: 38454010 DOI: 10.1038/s41366-024-01500-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 02/08/2024] [Accepted: 02/15/2024] [Indexed: 03/09/2024]
Abstract
BACKGROUND Glucagon-like peptide-1 (GLP-1) analogs are approved for the treatment of obesity in adults and adolescents. Reports have emerged that the weight loss effect of these medications may be related to changes in food preferences and ingestive behaviors following the treatment. Understanding the mechanisms which impact ingestive behavior could expand opportunities to develop more refined and personalized treatment options for obesity. METHODS Recent studies investigating the relationship between GLP-1 analogs and ingestive behaviors were retrieved from PubMed using the search terms: "obesity," "food preference," "taste," "ingestive behavior," "weight loss medication," "anti-obesity medication," "GLP-1 analog," "tirzepatide," "liraglutide," "semaglutide." Measurement tools were studied to compare variables used to assess food intake behavior. The main outcomes from each study were analyzed to evaluate the current standing and future directions of appetitive, ingestive, and consummatory behaviors and their association with GLP-1 analogs. RESULTS Thus far, studies have primarily explored the weight loss phase and report decreased short-term appetite and food intake upon treatment. However, research during the weight maintenance phase and objective measurements of food intake are notably sparse. Additionally, verbal reports have been primarily used to examine food intake, which can be susceptible to subjectivity. CONCLUSIONS Elucidating the relationship between GLP-1 analogs and ingestive behavior could reveal additional parameters which contribute to their anti-obesity effects. To better understand these mechanisms, it is imperative to consider objective measurements of food intake in future studies. Several measurement tools have been adapted to measure variables of food behavior in humans, and each must be carefully considered with their strengths and limitations to develop optimal investigations.
Collapse
Affiliation(s)
- Sahana Bettadapura
- Department of Neurosurgery, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | | | - Kelli Jablon
- Renaissance School of Medicine, Stonybrook University, Stonybrook, NY, USA
| | - Ahmed W Al-Humadi
- Diabetes Complications Research Centre, University College Dublin, Belfield, Ireland
| | - Carel W le Roux
- Diabetes Complications Research Centre, University College Dublin, Belfield, Ireland.
- Diabetes Research Centre, Ulster University, Belfast, UK.
| |
Collapse
|
2
|
Shankar K, Ramborger J, Bonnet-Zahedi S, Carrette LLG, George O. Acute nicotine intake increases feeding behavior through decreasing glucagon signaling in dependent male and female rats. Horm Behav 2024; 159:105447. [PMID: 37926623 PMCID: PMC11384237 DOI: 10.1016/j.yhbeh.2023.105447] [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: 06/21/2023] [Revised: 09/26/2023] [Accepted: 10/20/2023] [Indexed: 11/07/2023]
Abstract
Chronic use of nicotine is known to dysregulate metabolic signaling through altering circulating levels of feeding-related hormones, contributing to the onset of disorders like type 2 diabetes. However, little is known about the acute effects of nicotine on hormonal signaling. We previously identified an acute increase in food intake following acute nicotine, and we sought to determine whether this behavior was due to a change in hormone levels. We first identified that acute nicotine injection produces an increase in feeding behavior in dependent rats, but not nondependent rats. We confirmed that chronic nicotine use increases circulating levels of insulin, leptin, and ghrelin, and these correlate with rats' body weight and food intake. Acute nicotine injection in dependent animals decreased circulating GLP-1 and glucagon levels, and administration of glucagon prior to acute nicotine injection prevented the acute increase in feeding behavior. Thus, acute nicotine injection increases feeding behavior in dependent rats by decreasing glucagon signaling.
Collapse
Affiliation(s)
- Kokila Shankar
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA; The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Jarryd Ramborger
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA
| | - Sélène Bonnet-Zahedi
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA; Institut de Neurosciences de la Timone, Aix-Marseille Université, Marseille 13005, France
| | - Lieselot L G Carrette
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA
| | - Olivier George
- Department of Psychiatry, University of California San Diego, La Jolla, CA 92093, USA.
| |
Collapse
|
3
|
Boix-Castejón M, Roche E, Olivares-Vicente M, Álvarez-Martínez FJ, Herranz-López M, Micol V. Plant compounds for obesity treatment through neuroendocrine regulation of hunger: A systematic review. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2023; 113:154735. [PMID: 36921427 DOI: 10.1016/j.phymed.2023.154735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/07/2023] [Accepted: 02/22/2023] [Indexed: 06/18/2023]
Abstract
BACKGROUND Food intake behavior is influenced by both physiological and psychological complex processes, such as appetite, satiety, and hunger. The neuroendocrine regulation of food intake integrates short- and long-term acting signals that modulate the moment of intake and energy storage/expenditure, respectively. These signals are classified as orexigenic, those that activate anabolic pathways and the desire of eating, and anorexigenic, those that activate the catabolic pathways and a sensation of satiety. Appetite control by natural vegetal compounds is an intense area of research and new pharmacological interventions have been emerging based on an understanding of appetite regulation pathways. Several validated psychometric tools are used to assess the efficacy of these plant ingredients. However, these data are not conclusive if they are not complemented with physiological parameters, such as anthropometric evaluations (body weight and composition) and the analysis of hormones related to adipose tissue and appetite in blood. PURPOSE The purpose of this manuscript is the critical analysis of the plant compounds studied to date in the literature with potential for the neuroendocrine regulation of hunger in order to determine if the use of phytochemicals for the treatment of obesity constitutes an effective and/or promising therapeutic tool. METHODS Relevant information on neuroendocrine regulation of hunger and satiety for the treatment of obesity by plant compounds up to 2022 in English and/or Spanish were derived from online databases using the PubMed search engine and Google Scholar with relevant keywords and operators. RESULTS Accordingly, the comparison performed in this review between previous studies showed a high degree of experimental heterogeneity. Among the studies reviewed here, only a few of them establish comprehensively a potential correlation between the effect of the ingredient on hunger or satiety, body changes and a physiological response. CONCLUSIONS More systematic clinical studies are required in future research. The first approach should be to decode the pattern of circulating hormones regulating hunger, satiety, and appetite in overweight/obese subjects. Thereafter, studies should correlate brain connectivity at the level of the hypothalamus, gut and adipose tissue with the hormone patterns modulating appetite and satiety. Extracts whose mode of action have been well characterized and that are safe, can be used clinically to perform a moderate, but continuous, caloric restriction in overweight patients to lose weight excess into a controlled protocol.
Collapse
Affiliation(s)
- M Boix-Castejón
- Institute of Research, Development and Innovation in Health Biotechnology of Elche (IDiBE), Universitas Miguel Hernández (UMH), 03202, Elche, Spain
| | - E Roche
- Institute of Bioengineering, Applied Biology Department-Nutrition, University Miguel-Hernández, 03202, Elche, Spain; Instituto de Investigación Sanitaria y Biomédica de Alicante (ISABIAL), 03010, Alicante, Spain; CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), 28029, Madrid, Spain
| | - M Olivares-Vicente
- Institute of Research, Development and Innovation in Health Biotechnology of Elche (IDiBE), Universitas Miguel Hernández (UMH), 03202, Elche, Spain
| | - F J Álvarez-Martínez
- Institute of Research, Development and Innovation in Health Biotechnology of Elche (IDiBE), Universitas Miguel Hernández (UMH), 03202, Elche, Spain
| | - M Herranz-López
- Institute of Research, Development and Innovation in Health Biotechnology of Elche (IDiBE), Universitas Miguel Hernández (UMH), 03202, Elche, Spain.
| | - V Micol
- Institute of Research, Development and Innovation in Health Biotechnology of Elche (IDiBE), Universitas Miguel Hernández (UMH), 03202, Elche, Spain; CIBER Fisiopatología de la Obesidad y la Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), 28029, Madrid, Spain
| |
Collapse
|
4
|
Aldawsari M, Almadani FA, Almuhammadi N, Algabsani S, Alamro Y, Aldhwayan M. The Efficacy of GLP-1 Analogues on Appetite Parameters, Gastric Emptying, Food Preference and Taste Among Adults with Obesity: Systematic Review of Randomized Controlled Trials. Diabetes Metab Syndr Obes 2023; 16:575-595. [PMID: 36890965 PMCID: PMC9987242 DOI: 10.2147/dmso.s387116] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 01/14/2023] [Indexed: 03/06/2023] Open
Abstract
BACKGROUND Obesity is an epidemiological issue that negatively affects public health and has led to a high global burden on the healthcare system. Several approaches to control and overcome the obesity crisis have been established. However, Nobel discoverers found that glucagon-like peptide-1 analogues (GLP-1 analogues) positively regulate appetite and food intake, eventually leading to weight loss. OBJECTIVE The present systematic review aims to summarize the currently available evidence of the impact of GLP-1 analogues on appetite, gastric emptying, taste sensitivity, and food preferences among adults with obesity without other chronic diseases. METHODS A systematic literature search was conducted from October 2021 to December 2021 from three electronic databases (PubMed, Scopus, and ScienceDirect), including only randomized clinical trials (RCTs). Studies were based on the use of GLP-1 analogues, of any dosage and duration among adults with obesity without other medical diseases; studies measured appetite, gastric emptying, food preferences, and taste as a primary or secondary outcome. The risk of publication bias in each study was assessed independently using the updated Cochrane risk-of-bias tool (RoB2). RESULTS Twelve studies met the inclusion criteria with a total sample size of 445 participants. All the included studies measured at least one or more of the primary outcomes. The promising effect was evidenced by most studies showing appetite suppression, delayed gastric emptying, and changes in taste and food preferences. CONCLUSION GLP-1 analogues are effective obesity management therapy that could decrease food intake and eventually reduce weight by suppressing appetite, reducing hunger, decreasing gastric emptying, and altering food preferences and taste. However, high-quality, long-term, large sample size studies are crucial to examine the efficacy and effective dose of GLP-1 analogues intervention.
Collapse
Affiliation(s)
- Malikah Aldawsari
- Community Health Sciences Department, King Saud University, Riyadh, Saudi Arabia
- Correspondence: Malikah Aldawsari, Tel +966114670000, Fax +966114677580, Email
| | - Fatima A Almadani
- Community Health Sciences Department, King Saud University, Riyadh, Saudi Arabia
| | - Nujud Almuhammadi
- Community Health Sciences Department, King Saud University, Riyadh, Saudi Arabia
| | - Sarah Algabsani
- Community Health Sciences Department, King Saud University, Riyadh, Saudi Arabia
| | - Yara Alamro
- Community Health Sciences Department, King Saud University, Riyadh, Saudi Arabia
| | - Madhawi Aldhwayan
- Community Health Sciences Department, King Saud University, Riyadh, Saudi Arabia
| |
Collapse
|
5
|
Timmermans M, Topal B, Sanches EE, DE Jongh FW, Cagiltay E, Celik A, Ribeiro R, Parmar C, Ugale S, Proczko M, Stepaniak PS, Buise MP, Severin R, Pouwels S. The effects of glucagon like peptide-1 (GLP-1) on cardiac remodeling: exploring the role of medication and physiological modulation after metabolic surgery. Minerva Endocrinol (Torino) 2022; 47:449-459. [PMID: 33759444 DOI: 10.23736/s2724-6507.21.03296-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Obesity and associated comorbidities reach epidemic proportions nowadays. Several treatment strategies exist, but bariatric surgery has the only longstanding effects. Since a few years, there is increasing interest in the effects of gastro-intestinal hormones, in particular Glucagon-Like Peptide-1 (GLP-1) on the remission of Type 2 Diabetes (T2DM) and its effects on cardiac cardiovascular morbidity, cardiac remodeling, and mortality. In the past years several high quality multicenter randomized controlled trials were developed to assess the effects of GLP-1 receptor agonist therapy on cardiovascular morbidity and mortality. Most of the trials were designed and powered as non-inferiority trials to demonstrate cardiovascular safety. Most of these trials show a reduction in cardiovascular morbidity in patients with T2DM. Some follow-up studies indicate potential beneficial effects of GLP-1 receptor agonists on cardiovascular function in patients with heart failure, however the results are contradictory, and we need long-term studies to make firm conclusions about the pleiotropic properties of incretin-based therapies. However, it seems that GLP-1 receptor agonists have different effects than the increased GLP-1 production after bariatric surgery on cardiovascular remodeling. One of the hypotheses is that the blood concentrations of GLP-1 receptor agonists are three times higher compared to GLP-1 increase after bariatric and metabolic surgery. The purpose of this narrative review is to summarize the effects of GLP-1 on cardiovascular morbidity, mortality and remodeling due to medication but also due to bariatric and metabolic surgery. The second objective is to explain the possible differences in effects of GLP-1 agonists and bariatric and metabolic surgery.
Collapse
Affiliation(s)
- Marieke Timmermans
- Department of Surgery, Haaglanden Medical Center, The Hague, the Netherlands
| | - Besir Topal
- Department of Cardiothoracic Surgery, Onze Lieve Vrouwe Gasthuis, Amsterdam, the Netherlands
| | - Elijah E Sanches
- Department of Surgery, Haaglanden Medical Center, The Hague, the Netherlands
| | - Frank W DE Jongh
- Department of Plastic Surgery, Haaglanden Medical Center, The Hague, the Netherlands
| | - Eylem Cagiltay
- School of Medicine, Department of Physiology, Istanbul Bilim University, Istanbul, Turkey
| | | | - Rui Ribeiro
- Multidisciplinary Center for Metabolic Disease, Santo António Clinic, Amadora, Portugal
| | - Chetan Parmar
- Department of Surgery, Whittington Hospital, London, UK
| | - Surendra Ugale
- Bariatric and Metabolic Surgery Clinic, Virinchi Hospitals, Hyderabad, India
| | - Monika Proczko
- Department of General, Endocrine and Transplant Surgery, University Medical Center, Gdansk University, Gdansk, Poland
| | - Pieter S Stepaniak
- Department of Health Operations Management, Noordwest Hospital Group, Alkmaar, the Netherlands
| | - Marc P Buise
- Department of Anesthesiology, Intensive Care and Pain Medicine, Catharina Hospital, Eindhoven, the Netherlands
| | - Rich Severin
- Department of Physical Therapy, College of Applied Health Sciences, University of Illinois, Chicago, IL, USA.,Doctor of Physical Therapy Program, Robbins College of Health and Human Sciences, Baylor University, Waco, TX, USA
| | - Sjaak Pouwels
- Department of Intensive Care Medicine, Elisabeth-Tweesteden Hospital, Tilburg, the Netherlands -
| |
Collapse
|
6
|
Ahmed M, Badi S, Elidrisi A, Husain NE, Zainudin SB, Mahmood A, Abubaker NE, Alghamdi AS, Ahmed MH. Safety and effectiveness of newer antidiabetic medications during Ramadan fasting and safety of Ramadan fasting after bariatric surgery. J Diabetes Metab Disord 2022; 21:1991-2004. [PMID: 36404821 PMCID: PMC9672258 DOI: 10.1007/s40200-022-01145-6] [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: 08/02/2022] [Accepted: 10/10/2022] [Indexed: 11/27/2022]
Abstract
Background Fasting during Ramadan is mandatory for all adult healthy Muslims. International studies found that most Muslims with diabetes mellitus fast during Ramadan. The main risk factors are hypoglycemia, Hyperglycemia, diabetic ketoacidosis, and dehydration during fasting. Therefore, stratification of the risks for severe acute diabetes complications needs to be considered for each individual and strategies personalized to advert these complications. The advent of new diabetes medications which are effective yet with a better safety profile and monitoring of blood glucose levels during the day are important to reduce the risk of untoward effects of hypoglycemia and hyperglycemia during Ramadan fasting. Here we review the safety and effectiveness of the newer diabetes medications for Ramadan fasting and whether it is safe to perform fasting after bariatric surgery. Methods An extensive literature search using PubMed and Google Scholar was done using different search terms. The eligible studies were 48 randomized controlled trials, prospective observational studies, and reviews from January 2008 to June 2022 which were conducted in individuals living with diabetes. Results and Conclusions The newer diabetes medications such as GLP-1 agonists, DPP-4 inhibitors, SGLT-2 inhibitors, and new Insulin therapy are thought to be safe and effective during fasting of Ramadan. These medications are associated with a reduction in HbA1c, body weight, systolic blood pressure and risk of hypoglycemia during Ramadan fasting. However, further studies with larger sample size are needed to confirm the efficacy and safety of these newer medications during Ramadan fasting. Individuals with Bariatric surgery should seek advice and approval to fast from the bariatric dietician, physician, and surgeon before the beginning of the month of Ramadan.
Collapse
Affiliation(s)
- Musaab Ahmed
- College of Medicine, Ajman University, Ajman, United Arab Emirates
- Center of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman, United Arab Emirates
| | - Safaa Badi
- Department of Clinical Pharmacy, Faculty of Pharmacy, Omdurman Islamic University, Khartoum, Sudan
| | - Ala Elidrisi
- Department of Pathology, Faculty of Medicine and Health Sciences, Omdurman Islamic University, Khartoum, Sudan
| | - Nazik Elmalaika Husain
- Department of Pathology, Faculty of Medicine and Health Sciences, Omdurman Islamic University, Khartoum, Sudan
| | | | - Arshad Mahmood
- Department of Colorectal Surgery, Milton Keynes University Hospital NHS Foundation Trust, Eaglestone, Milton Keynes, Buckinghamshire UK
| | - Nuha Eljaili Abubaker
- Clinical Chemistry Department, College of Medical Laboratory Science, Sudan University of Science and Technology, Khartoum, Sudan
| | | | - Mohamed H. Ahmed
- Department of Medicine and HIV Metabolic Clinic, Milton Keynes University Hospital NHS Foundation Trust, Eaglestone, Milton Keynes, Buckinghamshire UK
| |
Collapse
|
7
|
Mori H, Verbeure W, Schol J, Carbone F, Tack J. Gastrointestinal hormones and regulation of gastric emptying. Curr Opin Endocrinol Diabetes Obes 2022; 29:191-199. [PMID: 35081068 DOI: 10.1097/med.0000000000000707] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW In this review, we evaluate recent findings related to the association between gastrointestinal hormones and regulation of gastric emptying. RECENT FINDINGS Motilin and ghrelin, which act during fasting, promote gastric motility, whereas most of the hormones secreted after a meal inhibit gastric motility. Serotonin has different progastric or antigastric motility effects depending on the receptor subtype. Serotonin receptor agonists have been used clinically to treat dyspepsia symptoms but other hormone receptor agonists or antagonists are still under development. Glucagon-like peptide 1 agonists, which have gastric motility and appetite-suppressing effects are used as a treatment for obesity and diabetes. SUMMARY Gastrointestinal hormones play an important role in the regulation of gastric motility. Various drugs have been developed to treat delayed gastric emptying by targeting gastrointestinal hormones or their receptors but few have been commercialized.
Collapse
Affiliation(s)
- Hideki Mori
- Translational Research Center for Gastrointestinal Disorders, KU Leuven, Leuven, Belgium
| | | | | | | | | |
Collapse
|
8
|
Smith KR, Moran TH. Gastrointestinal peptides in eating-related disorders. Physiol Behav 2021; 238:113456. [PMID: 33989649 PMCID: PMC8462672 DOI: 10.1016/j.physbeh.2021.113456] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 04/19/2021] [Accepted: 05/04/2021] [Indexed: 12/13/2022]
Abstract
Food intake is tightly controlled by homeostatic signals sensitive to metabolic need for the regulation of body weight. This review focuses on the peripherally-secreted gastrointestinal peptides (i.e., ghrelin, cholecystokinin, glucagon-like peptide 1, and peptide tyrosine tyrosine) that contribute to the control of appetite and discusses how these peptides or the signals arising from their release are disrupted in eating-related disorders across the weight spectrum, namely anorexia nervosa, bulimia nervosa, and obesity, and whether they are normalized following weight restoration or weight loss treatment. Further, the role of gut peptides in the pathogenesis and treatment response in human weight conditions as identified by rodent models are discussed. Lastly, we review the incretin- and hormone-based pharmacotherapies available for the treatment of obesity and eating-related disorders.
Collapse
Affiliation(s)
- Kimberly R Smith
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States.
| | - Timothy H Moran
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States
| |
Collapse
|
9
|
Schwartz A, Bellissimo N. Nicotine and energy balance: A review examining the effect of nicotine on hormonal appetite regulation and energy expenditure. Appetite 2021; 164:105260. [PMID: 33848592 DOI: 10.1016/j.appet.2021.105260] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 03/31/2021] [Accepted: 04/06/2021] [Indexed: 12/15/2022]
Abstract
Nicotine has been shown to decrease appetite, food intake (FI) and body weight, but the mechanisms are unclear. The purpose of this review was to examine research on the effects of nicotine on energy balance by exploring physiological mechanisms and hormone regulation related to FI, subjective appetite and energy expenditure (EE). We searched PubMed and MEDLINE, and included articles investigating the effects of nicotine on central appetite regulation, FI, leptin, peptide-YY (PYY), ghrelin, glucagon-like peptide-1 (GLP-1), adiponectin, cholecystokinin (CCK), orexin, and EE. A total of 65 studies were included in the qualitative synthesis and review. Our findings suggest that the decrease in appetite and FI may be attributed to nicotinic alterations of neuropeptide Y (NPY) and pro-opiomelanocortin (POMC) but the effect of nicotine on FI remains unclear. Furthermore, nicotine increases resting EE (REE) and physical activity EE (PAEE) in both smokers and non-smokers; and these increases may be a result of the catecholaminergic effect of nicotine. Decreases in body weight and appetite experienced by nicotine users results from increased EE and changes in the central hypothalamic regulation of appetite. There is not enough evidence to implicate a relationship between peripheral hormones and changes in appetite or FI after nicotine use. Although nicotine increases REE and PAEE, the effect of nicotine on other components of EE warrants further research. We conclude that further research evaluating the effect of nicotine on appetite hormones, FI and EE in humans is warranted.
Collapse
Affiliation(s)
| | - Nick Bellissimo
- School of Nutrition, Ryerson University, Toronto, Ontario, Canada.
| |
Collapse
|
10
|
Fang X, Du Z, Duan C, Zhan S, Wang T, Zhu M, Shi J, Meng J, Zhang X, Yang M, Zuo Y. Beinaglutide shows significantly beneficial effects in diabetes/obesity-induced nonalcoholic steatohepatitis in ob/ob mouse model. Life Sci 2021; 270:118966. [PMID: 33482185 DOI: 10.1016/j.lfs.2020.118966] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/21/2020] [Accepted: 12/22/2020] [Indexed: 12/12/2022]
Abstract
AIMS Beinaglutide has been approved for glucose lowering in type 2 diabetes mellitus (T2DM) in China. In addition to glycemic control, significant weight loss is observed from real world data. This study is designed to investigate the pharmacological and pharmacokinetic profiles of beinaglutide in different models. METHODS The pharmacological efficacy of beinaglutide was evaluated in C57BL/6 and ob/ob mice after single administration. Pharmacokinetic profiles in mice were investigated after single or multiple administration. Sub-chronic pharmacological efficacy was investigated in ob/ob mice for two weeks treatment and diet-induced ob/ob mice model of nonalcoholic steatohepatitis (NASH) for four weeks treatment. KEY FINDINGS Beinaglutide could dose-dependently reduce the glucose levels and improve insulin secretion in glucose tolerance tests, inhibit food intake and gastric emptying after single administration. At higher doses, beinaglutide could inhibit food intake over 4 h, which results in weight loss in ob/ob mice after about two weeks treatment. No tachyphylaxis is observed for beinaglutide in food intake with repeated administration. In NASH model, beinaglutide could reduce liver weight and hepatic steatosis and improve insulin sensitivity. Signiant changes of gene levels were observed in fatty acid β-oxidation (Ppara, Acadl, Acox1), mitochondrial function (Mfn1, Mfn2), antioxidation (Sod2), Sirt1, and et al. SIGNIFICANCE: Our results characterize the pharmacological and pharmacokinetic profiles of beinaglutide in mice and supported that chronic use of beinaglutde could lead to weight loss and reduce hepatic steatosis, which suggest beinaglutide may be effective therapy for the treatment of obesity and NASH.
Collapse
Affiliation(s)
- Xiankang Fang
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China.
| | - Zhiqiang Du
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Chunling Duan
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Shanshan Zhan
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Tian Wang
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Mengyu Zhu
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Jiajie Shi
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Juan Meng
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Xianhua Zhang
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Maiyun Yang
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| | - Yajun Zuo
- Innovation Center, Shanghai Benemae Pharmaceutical Corporation, 916 Ziping Road, Zhoupu, PuDong, Shanghai, China
| |
Collapse
|
11
|
Abstract
PURPOSE OF REVIEW Obesity affects over than 600 million adults worldwide resulting in multi-organ complications and major socioeconomic impact. The purpose of this review is to summarise the physiological effects as well as the therapeutic implications of the gut hormones glucagon-like peptide-1 (GLP-1), oxyntomodulin, peptide YY (PYY), and glucose-dependent insulinotropic peptide (GIP) in the treatment of obesity and type 2 diabetes. RECENT FINDINGS Clinical trials have proven that the widely used GLP-1 analogues have pleotropic effects beyond those on weight and glucose metabolism and appear to confer favourable cardiovascular and renal outcomes. However, GLP-1 analogues alone do not deliver sufficient efficacy for the treatment of obesity, being limited by their dose-dependent gastrointestinal side effects. Novel dual agonists for GLP-1/glucagon and GLP-1/GIP are being developed by the pharmaceutical industry and have demonstrated some promising results for weight loss and improvement in glycaemia over and above GLP-1 analogues. Triagonists (for example GLP-1/GIP/glucagon) are currently in pre-clinical or early clinical development. Gastrointestinal hormones possess complementary effects on appetite, energy expenditure, and glucose metabolism. We highlight the idea that combinations of these hormones may represent the way forward in obesity and diabetes therapeutics.
Collapse
Affiliation(s)
- Kleopatra Alexiadou
- Department of Digestion, Metabolism and Reproduction, Imperial College London, London, UK
| | - Tricia M-M Tan
- Department of Digestion, Metabolism and Reproduction, Imperial College London, London, UK.
| |
Collapse
|
12
|
Scotti L, Monteiro AFM, de Oliveira Viana J, Mendonça Junior FJB, Ishiki HM, Tchouboun EN, Santos R, Scotti MT. Multi-Target Drugs Against Metabolic Disorders. Endocr Metab Immune Disord Drug Targets 2020; 19:402-418. [PMID: 30556507 DOI: 10.2174/1871530319666181217123357] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/18/2018] [Accepted: 06/27/2018] [Indexed: 01/13/2023]
Abstract
BACKGROUND Metabolic disorders are a major cause of illness and death worldwide. Metabolism is the process by which the body makes energy from proteins, carbohydrates, and fats; chemically breaking these down in the digestive system towards sugars and acids which constitute the human body's fuel for immediate use, or to store in body tissues, such as the liver, muscles, and body fat. OBJECTIVE The efficiency of treatments for multifactor diseases has not been proved. It is accepted that to manage multifactor diseases, simultaneous modulation of multiple targets is required leading to the development of new strategies for discovery and development of drugs against metabolic disorders. METHODS In silico studies are increasingly being applied by researchers due to reductions in time and costs for new prototype synthesis; obtaining substances that present better therapeutic profiles. DISCUSSION In the present work, in addition to discussing multi-target drug discovery and the contributions of in silico studies to rational bioactive planning against metabolic disorders such as diabetes and obesity, we review various in silico study contributions to the fight against human metabolic pathologies. CONCLUSION In this review, we have presented various studies involved in the treatment of metabolic disorders; attempting to obtain hybrid molecules with pharmacological activity against various targets and expanding biological activity by using different mechanisms of action to treat a single pathology.
Collapse
Affiliation(s)
- Luciana Scotti
- Teaching and Research Management - University Hospital, Federal University of Paraíba, João Pessoa, PB, Brazil.,Postgraduate Program in Natural and Synthetic Bioactive Products, Federal University of Paraiba, Joao Pessoa, PB, Brazil
| | - Alex France Messias Monteiro
- Postgraduate Program in Natural and Synthetic Bioactive Products, Federal University of Paraiba, Joao Pessoa, PB, Brazil
| | - Jéssika de Oliveira Viana
- Postgraduate Program in Natural and Synthetic Bioactive Products, Federal University of Paraiba, Joao Pessoa, PB, Brazil
| | - Francisco Jaime Bezerra Mendonça Junior
- Postgraduate Program in Natural and Synthetic Bioactive Products, Federal University of Paraiba, Joao Pessoa, PB, Brazil.,Laboratory of Synthesis and Drug Delivery, Department of Biological Science, State University of Paraiba, Joao Pessoa, PB, Brazil
| | - Hamilton M Ishiki
- University of Western Sao Paulo (Unoeste), Presidente Prudente, SP, Brazil
| | | | - Rodrigo Santos
- Laboratory of Synthesis and Drug Delivery, Department of Biological Science, State University of Paraiba, Joao Pessoa, PB, Brazil
| | - Marcus Tullius Scotti
- Postgraduate Program in Natural and Synthetic Bioactive Products, Federal University of Paraiba, Joao Pessoa, PB, Brazil
| |
Collapse
|
13
|
Smith JK. Exercise, Obesity and CNS Control of Metabolic Homeostasis: A Review. Front Physiol 2018; 9:574. [PMID: 29867590 PMCID: PMC5965103 DOI: 10.3389/fphys.2018.00574] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 04/30/2018] [Indexed: 01/12/2023] Open
Abstract
This review details the manner in which the central nervous system regulates metabolic homeostasis in normal weight and obese rodents and humans. It includes a review of the homeostatic contributions of neurons located in the hypothalamus, the midbrain and limbic structures, the pons and the medullary area postrema, nucleus tractus solitarius, and vagus nucleus, and details how these brain regions respond to circulating levels of orexigenic hormones, such as ghrelin, and anorexigenic hormones, such as glucagon-like peptide 1 and leptin. It provides an insight as to how high intensity exercise may improve homeostatic control in overweight and obese subjects. Finally, it provides suggestions as to how further progress can be made in controlling the current pandemic of obesity and diabetes.
Collapse
Affiliation(s)
- John K Smith
- Departments of Academic Affairs and Biomedical Science, James H. Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| |
Collapse
|
14
|
de la Peña A, Cui X, Geiser J, Loghin C. No Dose Adjustment is Recommended for Digoxin, Warfarin, Atorvastatin or a Combination Oral Contraceptive When Coadministered with Dulaglutide. Clin Pharmacokinet 2017; 56:1415-1427. [DOI: 10.1007/s40262-017-0531-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
15
|
Seifu D, Gustafsson LE, Chawla R, Genet S, Debella A, Holst M, Hellström PM. Antidiabetic and gastric emptying inhibitory effect of herbal Melia azedarach leaf extract in rodent models of diabetes type 2 mellitus. J Exp Pharmacol 2017; 9:23-29. [PMID: 28360538 PMCID: PMC5365323 DOI: 10.2147/jep.s126146] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Diabetes type 2 is associated with impaired insulin production and increased insulin resistance. Treatment with antidiabetic drugs and insulin strives for normalizing glucose homeostasis. In Ethiopian traditional medicine, plant extracts of Melia azedarach are used to control diabetes mellitus and various gastrointestinal disorders. The objective of this study was to clarify the antidiabetic effects of M. azedarach leaf extracts in diabetic type 2 experimental animals. In this study, mice were injected with Melia extract intraperitoneally. Plasma glucose was studied by using tail vein sampling in acute experiments over 4 h and chronic experiments over 21 days with concurrent insulin and body weight assessments. Glucose tolerance was studied by using intraperitoneal glucose (2 mg/g) tolerance test over 120 min. Gastric emptying of a metabolically inert meal was studied by the gastric retention of a radioactive marker over 20 min. Melia extracts displayed acute, dose-dependent antidiabetic effects in ob/ob mice similar to glibenclamide (p<0.05–0.001). Long-term administration of Melia extract reduced plasma glucose (p<0.001) and insulin (p<0.01–0.001) levels over 21 days, concurrent with body weight loss. Glucose tolerance test showed reduced basal glucose levels (p<0.05–0.01), but no difference was found in glucose disposal after long-term treatment with Melia extract. In addition, the Melia extract at 400 mg/kg slowed gastric emptying rate of normal Sprague-Dawley (p<0.001) and diabetic Goto-Kakizaki rats (p<0.001) compared with controls. It is concluded that the M. azedarach leaf extract elicits diabetic activity through a multitargeted action. Primarily an increased insulin-sensitizing effect is at hand, resulting in blood glucose reduction and improved peripheral glucose disposal, but also through reduced gastric emptying and decreased insulin demand.
Collapse
Affiliation(s)
- Daniel Seifu
- Department of Biochemistry, College of Health Sciences, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia; Department of Medical Sciences, Uppsala University, Uppsala
| | - Lars E Gustafsson
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Rajinder Chawla
- Department of Biochemistry, College of Health Sciences, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
| | - Solomon Genet
- Department of Biochemistry, College of Health Sciences, School of Medicine, Addis Ababa University, Addis Ababa, Ethiopia
| | - Asfaw Debella
- Department of Traditional Drug Development, Ethiopian Health and Nutrition Research Institute, Addis Ababa, Ethiopia
| | - Mikael Holst
- Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | | |
Collapse
|
16
|
Koski M, Naukkarinen H. Severe obesity, emotions and eating habits: a case-control study. BMC OBESITY 2017; 4:2. [PMID: 28078092 PMCID: PMC5219768 DOI: 10.1186/s40608-016-0138-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 12/18/2016] [Indexed: 11/10/2022]
Abstract
BACKGROUND Obesity has a multifaceted etiology that involves genetic, biological and behavioral factors, body growth, eating habits, energy expenditure and the function of adipose tissue. The present study aimed to expand upon knowledge about the relationships among obesity, emotions and eating habits in severely obese individuals using a case-control method. METHODS The subject group consisted of 112 individuals (81 females and 31 males) receiving a permanent disability pension primarily for obesity. The control subjects were randomly selected from the same area and were receiving a disability pension for a different primary illness. The controls were matched with the subjects by the place of residence, sex, age, the time since the pension was granted and occupation. Psychiatric interviews were conducted on all participants. The results were analyzed using the chi-squared test (χ2-test) and the percent distribution. The subject and control groups were compared using the t-test for paired variables. Conditional logistic regression analysis was also conducted. RESULTS The emotional state of eating was significantly associated with quarrels and feelings of loneliness. The subjects suffered from night eating syndrome, which was associated with an increased risk of early retirement. Binge eating syndrome was observed more frequently in the study group. The subjects reported feeling increased hunger compared with the controls. A significant percentage of the subjects had a body mass index of ≥ 40. No differences in eating habits were observed between the groups. CONCLUSION This study provides information on the relationship between emotions and eating habits in obesity, which is a rarely studied topic. We believe that our study provides a novel and necessary overview of the associations among severe obesity, emotions and eating habits.
Collapse
Affiliation(s)
- M Koski
- University of Helsinki, Helsinki, Finland
| | - H Naukkarinen
- Carea Hospital District, Kymenlaakso Psychiatric Hospital, University of Helsinki, Töölönkatu 26 C 55, 00260 Helsinki, Finland
| |
Collapse
|
17
|
Zhang Y, Liu J, Yao J, Ji G, Qian L, Wang J, Zhang G, Tian J, Nie Y, Zhang YE, Gold MS, Liu Y. Obesity: pathophysiology and intervention. Nutrients 2014; 6:5153-83. [PMID: 25412152 PMCID: PMC4245585 DOI: 10.3390/nu6115153] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 07/21/2014] [Accepted: 10/29/2014] [Indexed: 01/09/2023] Open
Abstract
Obesity presents a major health hazard of the 21st century. It promotes co-morbid diseases such as heart disease, type 2 diabetes, obstructive sleep apnea, certain types of cancer, and osteoarthritis. Excessive energy intake, physical inactivity, and genetic susceptibility are main causal factors for obesity, while gene mutations, endocrine disorders, medication, or psychiatric illnesses may be underlying causes in some cases. The development and maintenance of obesity may involve central pathophysiological mechanisms such as impaired brain circuit regulation and neuroendocrine hormone dysfunction. Dieting and physical exercise offer the mainstays of obesity treatment, and anti-obesity drugs may be taken in conjunction to reduce appetite or fat absorption. Bariatric surgeries may be performed in overtly obese patients to lessen stomach volume and nutrient absorption, and induce faster satiety. This review provides a summary of literature on the pathophysiological studies of obesity and discusses relevant therapeutic strategies for managing obesity.
Collapse
Affiliation(s)
- Yi Zhang
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China.
| | - Ju Liu
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China.
| | - Jianliang Yao
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China.
| | - Gang Ji
- Xijing Gastrointestinal Hospital, the Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
| | - Long Qian
- Department of Biomedical Engineering, Peking University, Beijing 100871, China.
| | - Jing Wang
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China.
| | - Guansheng Zhang
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China.
| | - Jie Tian
- School of Life Science and Technology, Xidian University, Xi'an, Shaanxi 710071, China.
| | - Yongzhan Nie
- Xijing Gastrointestinal Hospital, the Fourth Military Medical University, Xi'an, Shaanxi 710032, China.
| | - Yi Edi Zhang
- Department of Psychiatry & McKnight Brain Institute, University of Florida, 1149 South Newell Drive, Gainesville, FL 32610, USA.
| | - Mark S Gold
- Department of Psychiatry & McKnight Brain Institute, University of Florida, 1149 South Newell Drive, Gainesville, FL 32610, USA.
| | - Yijun Liu
- Department of Psychiatry & McKnight Brain Institute, University of Florida, 1149 South Newell Drive, Gainesville, FL 32610, USA.
| |
Collapse
|
18
|
Walter CP, Bleske BE, Dorsch MP. Pharmacotherapy for weight loss: the cardiovascular effects of the old and new agents. J Clin Pharm Ther 2014; 39:475-84. [DOI: 10.1111/jcpt.12177] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 04/23/2014] [Indexed: 01/19/2023]
Affiliation(s)
- C. P. Walter
- Department of Pharmacy; Allegheny General Hospital; Pittsburgh PA USA
| | - B. E. Bleske
- University of Michigan; College of Pharmacy; Ann Arbor MI USA
| | - M. P. Dorsch
- University of Michigan; College of Pharmacy; Ann Arbor MI USA
- Department of Pharmacy Services; University of Michigan Hospitals and Health Centers; University of Michigan; Ann Arbor MI USA
| |
Collapse
|
19
|
Torekov SS, Holst JJ, Ehlers MR. Dose response of continuous subcutaneous infusion of recombinant glucagon-like peptide-1 in combination with metformin and sulphonylurea over 12 weeks in patients with type 2 diabetes mellitus. Diabetes Obes Metab 2014; 16:451-6. [PMID: 24251641 DOI: 10.1111/dom.12240] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 10/15/2013] [Accepted: 11/12/2013] [Indexed: 11/28/2022]
Abstract
AIMS Any differences observed between natural glucagon-like peptide-1 (GLP-1) and studies obtained with analogues might call for renewed considerations concerning the use and design of such analogues. Thus, we aimed to evaluate the dose-response relationship of recombinant glucagon-like peptide-1 (7-36) amide (rGLP-1) administered by continuous subcutaneous infusion (CSCI) in subjects with type 2 diabetes. METHODS We compared the efficacy and safety of three doses of recombinant GLP-1, ranging from 1.25 to 5.0 pmol/kg/min (pkm) and placebo, given by continuous subcutaneous infusion over 3 months in combination with metformin and sulphonylurea (SU), to lower haemoglobin A1c (HbA1c), fasting plasma glucose and weight in 95 type 2 diabetes patients with inadequate glycaemic control. RESULTS The mean decreases in HbA1c at endpoint (week 12) were significantly greater for all three rGLP-1 dose groups when each was compared with the placebo group, with the greatest decrease occurring in the 5.0 pkm dose group (-1.3%, s.d. ± 0.18, p < 0.001). The mean decreases in fasting plasma glucose from baseline to endpoint were significantly greater for all three rGLP-1 dose groups than for the placebo group, with the greatest decrease occurring in the 5.0 pkm dose group (-26.0 mg/dl, s.d. ± 8.5, p = 0.02). Body weight was significantly reduced by 1.8 kg (s.d. ± 1.3) in the 1.25 pkm dose group only (p = 0.04). CONCLUSIONS Administration of rGLP-1 by CSCI over a 12-week period in combination with metformin and an SU had a dose dependent effect in lowering HbA1c and fasting plasma glucose. However, administration of rGLP-1 by CSCI may be less effective with respect to lowering of body weight compared with the daily and once weekly analogues.
Collapse
Affiliation(s)
- S S Torekov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | | |
Collapse
|
20
|
Umapathysivam MM, Lee MY, Jones KL, Annink CE, Cousins CE, Trahair LG, Rayner CK, Chapman MJ, Nauck MA, Horowitz M, Deane AM. Comparative effects of prolonged and intermittent stimulation of the glucagon-like peptide 1 receptor on gastric emptying and glycemia. Diabetes 2014; 63:785-90. [PMID: 24089511 PMCID: PMC3900552 DOI: 10.2337/db13-0893] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Acute administration of glucagon-like peptide 1 (GLP-1) and its agonists slows gastric emptying, which represents the major mechanism underlying their attenuation of postprandial glycemic excursions. However, this effect may diminish during prolonged use. We compared the effects of prolonged and intermittent stimulation of the GLP-1 receptor on gastric emptying and glycemia. Ten healthy men received intravenous saline (placebo) or GLP-1 (0.8 pmol/kg ⋅ min), as a continuous 24-h infusion ("prolonged"), two 4.5-h infusions separated by 20 h ("intermittent"), and a 4.5-h infusion ("acute") in a randomized, double-blind, crossover fashion. Gastric emptying of a radiolabeled mashed potato meal was measured using scintigraphy. Acute GLP-1 markedly slowed gastric emptying. The magnitude of the slowing was attenuated with prolonged but maintained with intermittent infusions. GLP-1 potently diminished postprandial glycemia during acute and intermittent regimens. These observations suggest that short-acting GLP-1 agonists may be superior to long-acting agonists when aiming specifically to reduce postprandial glycemic excursions in the treatment of type 2 diabetes.
Collapse
Affiliation(s)
| | - Michael Y. Lee
- Discipline of Acute Care Medicine, University of Adelaide, Adelaide, Australia
| | - Karen L. Jones
- Discipline of Medicine, University of Adelaide, Adelaide, Australia
| | | | - Caroline E. Cousins
- Department of Critical Care Services, Royal Adelaide Hospital, Adelaide, Australia
| | | | - Chris K. Rayner
- Discipline of Medicine, University of Adelaide, Adelaide, Australia
| | - Marianne J. Chapman
- Discipline of Acute Care Medicine, University of Adelaide, Adelaide, Australia
- Department of Critical Care Services, Royal Adelaide Hospital, Adelaide, Australia
| | | | - Michael Horowitz
- Discipline of Medicine, University of Adelaide, Adelaide, Australia
| | - Adam M. Deane
- Discipline of Acute Care Medicine, University of Adelaide, Adelaide, Australia
- Department of Critical Care Services, Royal Adelaide Hospital, Adelaide, Australia
- Corresponding author: Adam M. Deane,
| |
Collapse
|
21
|
Salem V, Bloom SR. Approaches to the pharmacological treatment of obesity. Expert Rev Clin Pharmacol 2014; 3:73-88. [DOI: 10.1586/ecp.09.54] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
|
22
|
Werner U. Effects of the GLP-1 receptor agonist lixisenatide on postprandial glucose and gastric emptying--preclinical evidence. J Diabetes Complications 2014; 28:110-4. [PMID: 23992745 DOI: 10.1016/j.jdiacomp.2013.06.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Revised: 05/30/2013] [Accepted: 06/11/2013] [Indexed: 11/15/2022]
Abstract
In addition to promoting glucose homeostasis, glucagon-like peptide 1 (GLP-1) has a number of extra-pancreatic effects that regulate appetite and body weight. GLP-1 delays gastric emptying, which is vital for postprandial glucose (PPG) control. As GLP-1 is rapidly degraded by protease dipeptidyl peptidase-4, a number of degradation-resistant GLP-1 receptor agonists (GLP-1RAs) have been developed for the treatment of Type 2 diabetes mellitus. These agents can be broadly categorized as being short- or long-acting, based on their pharmacokinetic profile. Short-acting agonists predominantly affect PPG and delay gastric emptying in a sustained manner, whereas long-acting agents largely affect fasting plasma glucose and their delay in gastric emptying appears to be subjected to tachyphylaxis. Lixisenatide is a "short-acting" once-daily prandial GLP-1RA. This review provides an overview of the preclinical studies that are currently available and that evaluate the efficacy of lixisenatide on gastric emptying and PPG levels. The preclinical evidence outlined in this review supports the efficacy of lixisenatide in reducing PPG excursions and delaying gastric emptying. Furthermore, in contrast to long-acting agents, the actions of lixisenatide do not appear to be subjected to tachyphylaxis.
Collapse
Affiliation(s)
- Ulrich Werner
- Sanofi-Aventis Deutschland GmbH, Frankfurt am Main, Germany.
| |
Collapse
|
23
|
Kim GW, Lin JE, Blomain ES, Waldman SA. Antiobesity pharmacotherapy: new drugs and emerging targets. Clin Pharmacol Ther 2013; 95:53-66. [PMID: 24105257 DOI: 10.1038/clpt.2013.204] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/18/2013] [Indexed: 02/07/2023]
Abstract
Obesity is a growing pandemic, and related health and economic costs are staggering. Pharmacotherapy, partnered with lifestyle modifications, forms the core of current strategies to reduce the burden of this disease and its sequelae. However, therapies targeting weight loss have a significant history of safety risks, including cardiovascular and psychiatric events. Here, evolving strategies for developing antiobesity therapies, including targets, mechanisms, and developmental status, are highlighted. Progress in this field is underscored by Belviq (lorcaserin) and Qsymia (phentermine/topiramate), the first agents in more than 10 years to achieve regulatory approval for chronic weight management in obese patients. On the horizon, novel insights into metabolism and energy homeostasis reveal guanosine 3',5'-cyclic monophosphate (cGMP) signaling circuits as emerging targets for antiobesity pharmacotherapy. These innovations in molecular discovery may elegantly align with practical off-the-shelf approaches, leveraging existing approved drugs that modulate cGMP levels for the management of obesity.
Collapse
Affiliation(s)
- G W Kim
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - J E Lin
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - E S Blomain
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - S A Waldman
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| |
Collapse
|
24
|
Nicolini A, Ferrari P, Masoni MC, Fini M, Pagani S, Giampietro O, Carpi A. Malnutrition, anorexia and cachexia in cancer patients: A mini-review on pathogenesis and treatment. Biomed Pharmacother 2013; 67:807-17. [DOI: 10.1016/j.biopha.2013.08.005] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Accepted: 08/10/2013] [Indexed: 12/17/2022] Open
|
25
|
Atalayer D, Astbury NM. Anorexia of aging and gut hormones. Aging Dis 2013; 4:264-75. [PMID: 24124632 DOI: 10.14336/ad.2013.0400264] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 08/02/2013] [Accepted: 08/02/2013] [Indexed: 12/20/2022] Open
Abstract
We are expected to live longer than if we had been born 100 years ago however, the additional years are not necessarily spent in good health or free from disability. Body composition changes dramatically over the course of life. There is a gradual increase in body weight throughout adult life until the age of about 60-65 years. In contrast, body weight appears to decrease with age after the age of 65-75 years, even in those demonstrating a previous healthy body weight. This age related decrease in body weight, often called unintentional weight loss or involuntary weight loss can be a significant problem for the elderly. This has been shown to be related to decline in appetite and food intake is common amongst the elderly and is often referred to the anorexia of aging. Underlying mechanisms regulate energy homeostasis and appetite may change as people age. In this review, peripheral factors regulating appetite have been summarized in regards to their age-dependent changes and role in the etiology of anorexia of aging. Understanding the alterations in the mechanisms regulating appetite and food intake in conjunction with aging may help inform strategies that promote healthy aging and promote health and wellbeing in the elderly years, with the end goal to add life to the years and not just years to our lives.
Collapse
Affiliation(s)
- Deniz Atalayer
- Department of Institute of Human Nutrition, Columbia University College of Physicians and Surgeons, New York, NY 10025, USA ; Department of Medicine, New York Obesity Research and Nutrition Center, St. Luke's-Roosevelt Hospital, New York, NY 10025, USA
| | | |
Collapse
|
26
|
Kim GW, Lin JE, Blomain ES, Waldman SA. New advances in models and strategies for developing anti-obesity drugs. Expert Opin Drug Discov 2013; 8:655-71. [PMID: 23621300 DOI: 10.1517/17460441.2013.792804] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Obesity is a worldwide pandemic. Obesity-related health and economic costs are staggering. Existing strategies to combat obesity through lifestyle improvements and medical intervention have had limited success. Pharmacotherapy, in combination with lifestyle modification, may play a vital role in reversing the disease burden. However, past and current weight-loss medications have had serious safety risks, notably cardiovascular and psychiatric events. AREAS COVERED The authors review the strategies for designing new anti-obesity drugs by describing those currently in development. They describe their target, mechanism of action and developmental or regulatory status. Furthermore, they discuss the problem of weight regain following weight loss, and its relevance to the long-term success of anti-obesity pharmacotherapy. EXPERT OPINION For weight management drugs to achieve the safety and efficacy required to be impactful, current studies are uncovering and characterizing new targets, including new signaling circuits and hormones regulating appetite and metabolism, and re-evaluating the role of pharmacotherapy in weight management. To avoid the safety failures of many past weight-loss drugs, the models and strategies covered in this article incorporate recent advances in knowledge and technology. We discuss the emergence of cGMP signaling as a potentially transformative target in weight management. Modulating cGMP signaling may represent an ideal goal for an anti-obesity pharmacotherapy, reflecting some of the major themes described in the present review: targeting pathways that are newly realized as relevant for weight management; promoting safety by re-purposing drugs that are safe, proven, and approved for clinical use; and having a synergistic effect on multiple, reinforcing pathways.
Collapse
Affiliation(s)
- Gilbert W Kim
- Thomas Jefferson University, Department of Pharmacology and Experimental Therapeutics, Philadelphia, PA 19107, USA
| | | | | | | |
Collapse
|
27
|
Obesidad: análisis etiopatogénico y fisiopatológico. ACTA ACUST UNITED AC 2013; 60:17-24. [DOI: 10.1016/j.endonu.2012.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Revised: 02/28/2012] [Accepted: 03/05/2012] [Indexed: 12/25/2022]
|
28
|
Ueda SY, Nakahara H, Miyamoto T. Effects of exercise on glucagon-like peptide-1 (GLP-1). THE JOURNAL OF PHYSICAL FITNESS AND SPORTS MEDICINE 2013. [DOI: 10.7600/jpfsm.2.221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
|
29
|
Colon-Gonzalez F, Kim GW, Lin JE, Valentino MA, Waldman SA. Obesity pharmacotherapy: what is next? Mol Aspects Med 2012; 34:71-83. [PMID: 23103610 DOI: 10.1016/j.mam.2012.10.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The increase in obesity in the Unites States and around the world in the last decade is overwhelming. The number of overweight adults in the world surpassed 1 billion in 2008. Health hazards associated with obesity are serious and include heart disease, sleep apnea, diabetes, and cancer. Although lifestyle modifications are the most straightforward way to control weight, a large portion of the population may not be able to rely on this modality alone. Thus, the development of anti-obesity therapeutics represents a major unmet medical need. Historically, anti-obesity pharmacotherapies have been unsafe and minimally efficacious. A better understanding of the biology of appetite and metabolism provides an opportunity to develop drugs that may offer safer and more effective alternatives for weight management. This review discusses drugs that are currently on the market and in development as anti-obesity therapeutics based on their target and mechanism of action. It should serve as a roadmap to establish expectations for the near future for anti-obesity drug development.
Collapse
Affiliation(s)
- Francheska Colon-Gonzalez
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, Philadelphia, PA, United States.
| | | | | | | | | |
Collapse
|
30
|
Kim GW, Lin JE, Valentino MA, Colon-Gonzalez F, Waldman SA. Regulation of appetite to treat obesity. Expert Rev Clin Pharmacol 2012; 4:243-59. [PMID: 21666781 DOI: 10.1586/ecp.11.3] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Obesity has escalated into a pandemic over the past few decades. In turn, research efforts have sought to elucidate the molecular mechanisms underlying the regulation of energy balance. A host of endogenous mediators regulate appetite and metabolism, and thereby control both short- and long-term energy balance. These mediators, which include gut, pancreatic and adipose neuropeptides, have been targeted in the development of anti-obesity pharmacotherapy, with the goal of amplifying anorexigenic and lipolytic signaling or blocking orexigenic and lipogenic signaling. This article presents the efficacy and safety of these anti-obesity drugs.
Collapse
Affiliation(s)
- Gilbert W Kim
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 132 S. 10th Street, 1170 Main, Philadelphia, PA 19107, USA
| | | | | | | | | |
Collapse
|
31
|
Fineman MS, Cirincione BB, Maggs D, Diamant M. GLP-1 based therapies: differential effects on fasting and postprandial glucose. Diabetes Obes Metab 2012; 14:675-88. [PMID: 22233527 DOI: 10.1111/j.1463-1326.2012.01560.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Glucagon-like peptide-1 (GLP-1), a gut-derived hormone secreted in response to nutrients, has several glucose and weight regulating actions including enhancement of glucose-stimulated insulin secretion, suppression of glucagon secretion, slowing of gastric emptying and reduction in food intake. Because of these multiple effects, the GLP-1 receptor system has become an attractive target for type 2 diabetes therapies. However, GLP-1 has significant limitations as a therapeutic due to its rapid degradation (plasma half-life of 1-2 min) by dipeptidyl peptidase-4 (DPP-4). Two main classes of GLP-1-mediated therapies are now in use: DPP-4 inhibitors that reduce the degradation of GLP-1 and DPP-4-resistant GLP-1 receptor (GLP-1R) agonists. The GLP-1R agonists can be further divided into short- and long-acting formulations which have differential effects on their mechanisms of action, ultimately resulting in differential effects on their fasting and postprandial glucose lowering potential. This review summarizes the similarities and differences among DPP-4 inhibitors, short-acting GLP-1R agonists and long-acting GLP-1R agonists. We propose that these different GLP-1-mediated therapies are all necessary tools for the treatment of type 2 diabetes and that the choice of which one to use should depend on the specific needs of the patient. This is analogous to the current use of modern insulins, as short-, intermediate- and long-acting versions are all used to optimize the 24-h plasma glucose profile as needed. Given that GLP-1-mediated therapies have advantages over insulins in terms of hypoglycaemic risk and weight gain, optimized use of these compounds could represent a significant paradigm shift for the treatment of type 2 diabetes.
Collapse
Affiliation(s)
- M S Fineman
- Elcelyx Therapeutics, Inc., San Diego, CA, USA.
| | | | | | | |
Collapse
|
32
|
Svendsen PF, Jensen FK, Holst JJ, Haugaard SB, Nilas L, Madsbad S. The effect of a very low calorie diet on insulin sensitivity, beta cell function, insulin clearance, incretin hormone secretion, androgen levels and body composition in obese young women. Scandinavian Journal of Clinical and Laboratory Investigation 2012; 72:410-9. [PMID: 22708619 DOI: 10.3109/00365513.2012.691542] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Evaluation of the effect of an 8-week very low calorie diet (VLCD, 500-600 kcal daily) on weight, body fat distribution, glucose, insulin and lipid metabolism, androgen levels and incretin secretion in obese women. METHODS Seventeen overweight women (BMI > 28) were recruited to the study. Glucose, insulin and lipid metabolism were evaluated by euglycemic clamp technique, indirect calorimetry and an oral glucose tolerance test (OGTT). Insulin sensitivity was calculated as glucose disposal rate (GDR) and insulin sensitivity index (ISI), and also by HOMA-IR. Insulin secretion rate (ISR) was calculated from plasma C-peptide measurements. Secretion of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) was measured during an oral glucose tolerance test. Abdominal fat distribution was assessed by dual x-ray absorptiometry scan and computed tomography. RESULTS Ten women completed the intervention. The subjects lost an average 11% of their baseline weight. There was a significant loss of subcutaneous abdominal fatty tissue (p < 0.01) and intra-abdominal fatty tissue (p =0.05). Whole body (HOMA-IR) (p < 0.05) insulin sensitivity increased significantly, but peripheral (ISI) insulin sensitivity was unaltered after weight loss. GIP increased (p < 0.05) and GLP-1 was unaltered after the dietary intervention. Insulin responses did not differ before and after dietary intervention, however, a significant increase in insulin clearance (p < 0.05) was observed. The weight loss resulted in a significant decrease in free testosterone. CONCLUSION A VLCD is an effective weight loss treatment, which results in an immediate improvement in several metabolic parameters.
Collapse
Affiliation(s)
- Pernille F Svendsen
- Department of Obstetrics and Gynaecology,Copenhagen University Hospital at Hvidovre, Hvidovre, Denmark.
| | | | | | | | | | | |
Collapse
|
33
|
De Silva A, Bloom SR. Gut Hormones and Appetite Control: A Focus on PYY and GLP-1 as Therapeutic Targets in Obesity. Gut Liver 2012; 6:10-20. [PMID: 22375166 PMCID: PMC3286726 DOI: 10.5009/gnl.2012.6.1.10] [Citation(s) in RCA: 213] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 07/19/2011] [Indexed: 01/01/2023] Open
Abstract
The global obesity epidemic has resulted in significant morbidity and mortality. However, the medical treatment of obesity is limited. Gastric bypass is an effective surgical treatment but carries significant perioperative risks. The gut hormones, peptide tyrosine tyrosine (PYY) and glucagon-like peptide 1 (GLP-1), are elevated following gastric bypass and have been shown to reduce food intake. They may provide new therapeutic targets. This review article provides an overview of the central control of food intake and the role of PYY and GLP-1 in appetite control. Key translational animal and human studies are reviewed.
Collapse
Affiliation(s)
- Akila De Silva
- Department of Diabetes, Endocrinology and Metabolism, Hammersmith Campus, Imperial College London, London, UK
| | | |
Collapse
|
34
|
Abstract
GLP-1 receptors are expressed in the brain, especially in the regions responsible for the regulation of food intake, and intracerebroventricular injection of GLP-1 results in inhibition of food intake. Peripheral administration of GLP-1 dose-dependently enhances satiety and reduces food intake in normal and obese subjects as well as in type 2 diabetic patients. So far, the mechanisms by which GLP-1 exerts its effects are not completely clear. Interactions with neurons in the gastrointestinal tract or possibly direct access to the brain through the blood-brain barrier as observed in rats are possible and discussed in this chapter as well as a novel hypothesis based on the finding that GLP-1 is also expressed in taste cells. Finally, the role of GLP-1 receptor agonists as a possible treatment option in obesity is discussed as well as the role of GLP-1 in the effects of bariatric surgery on adiposity and glucose homeostasis.
Collapse
|
35
|
Horner KM, Byrne NM, Cleghorn GJ, Näslund E, King NA. The effects of weight loss strategies on gastric emptying and appetite control. Obes Rev 2011; 12:935-51. [PMID: 21729233 DOI: 10.1111/j.1467-789x.2011.00901.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The gastrointestinal tract plays an important role in the improved appetite control and weight loss in response to bariatric surgery. Other strategies which similarly alter gastrointestinal responses to food intake could contribute to successful weight management. The aim of this review is to discuss the effects of surgical, pharmacological and behavioural weight loss interventions on gastrointestinal targets of appetite control, including gastric emptying. Gastrointestinal peptides are also discussed because of their integrative relationship in appetite control. This review shows that different strategies exert diverse effects and there is no consensus on the optimal strategy for manipulating gastric emptying to improve appetite control. Emerging evidence from surgical procedures (e.g. sleeve gastrectomy and Roux-en-Y gastric bypass) suggests a faster emptying rate and earlier delivery of nutrients to the distal small intestine may improve appetite control. Energy restriction slows gastric emptying, while the effect of exercise-induced weight loss on gastric emptying remains to be established. The limited evidence suggests that chronic exercise is associated with faster gastric emptying, which we hypothesize will impact on appetite control and energy balance. Understanding how behavioural weight loss interventions (e.g. diet and exercise) alter gastrointestinal targets of appetite control may be important to improve their success in weight management.
Collapse
Affiliation(s)
- K M Horner
- Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
| | | | | | | | | |
Collapse
|
36
|
Zhang J, Ritter RC. Circulating GLP-1 and CCK-8 reduce food intake by capsaicin-insensitive, nonvagal mechanisms. Am J Physiol Regul Integr Comp Physiol 2011; 302:R264-73. [PMID: 22031786 DOI: 10.1152/ajpregu.00114.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Previous reports suggest that glucagon-like peptide (GLP-1), a peptide secreted from the distal small intestine, is an endocrine satiation signal. Nevertheless, there are conflicting reports regarding the site where circulating GLP-1 acts to reduce food intake. To test the hypothesis that vagal afferents are necessary for reduction of food intake by circulating GLP-1, we measured intake of 15% sucrose during intravenous GLP-1 infusion in intact, vagotomized, and capsaicin-treated rats. We also measured sucrose intake during intravenous infusion of cholecystokinin, a peptide known to reduce food intake via abdominal vagal afferents. We found that reduction of intake by GLP-1 was not diminished by capsaicin treatment or vagotomy. In fact, reduction of sucrose intake by our highest GLP-1 dose was enhanced in vagotomized and capsaicin-treated rats. Intravenous GLP-1 induced comparable increases of hindbrain c-Fos immunoreactivity in intact, capsaicin-treated, and vagotomized rats. Plasma concentrations of active GLP-1 in capsaicin-treated rats did not differ from those of controls during the intravenous infusions. Finally, capsaicin treatment was not associated with altered GLP-1R mRNA in the brain, but nodose ganglia GLP-1R mRNA was significantly reduced in capsaicin-treated rats. Although reduction of food intake by intraperitoneal cholecystokinin was abolished in vagotomized and capsaicin-treated rats, reduction of intake by intravenous cholecystokinin was only partially attenuated. These results indicate that vagal or capsaicin-sensitive neurons are not necessary for reduction of food intake by circulating (endocrine) GLP-1, or cholecystokinin. Vagal participation in satiation by these peptides may be limited to paracrine effects exerted near the sites of their secretion.
Collapse
Affiliation(s)
- Jingchuan Zhang
- Programs in Neuroscience and Dept. of Veterinary and Comparative Anatomy, Pharmacology, and Physiology, Washington State Univ., Pullman, WA 99164-6520, USA
| | | |
Collapse
|
37
|
Naessén S, Carlström K, Holst JJ, Hellström PM, Hirschberg AL. Women with bulimia nervosa exhibit attenuated secretion of glucagon-like peptide 1, pancreatic polypeptide, and insulin in response to a meal. Am J Clin Nutr 2011; 94:967-72. [PMID: 21813805 DOI: 10.3945/ajcn.111.014837] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND The eating disorder bulimia nervosa (BN) is characterized by frequent episodes of binge eating, followed regularly by inappropriate compensatory behavior, such as self-induced vomiting. OBJECTIVE The current investigation was designed to examine possible alterations in the secretion of the gastrointestinal satiety peptides glucagon-like peptide 1 (GLP-1) and pancreatic polypeptide (PP) in women with BN. DESIGN Twenty-one women with BN and 17 healthy control subjects of comparable age and BMI were recruited. After fasting overnight, the subjects provided blood samples during ingestion of a standardized meal and self-rated their appetite on a visual analog scale. Fasting and meal-related secretion of the incretin GLP-1 and the meal-related feedback signal PP and insulin and glucose as indicators of the metabolic homeostasis were analyzed. RESULTS Women with BN had significantly lower fasting and postprandial serum concentrations of GLP-1 (P < 0.01) and PP (P < 0.05) than did the control subjects. Furthermore, both the basal (P < 0.001) and peak (P < 0.05) concentrations of insulin were significantly attenuated in the bulimic subjects, whereas glucose concentrations were normal. As a consequence, the bulimic homeostasis model assessment of insulin index values were also lower (P < 0.001). CONCLUSIONS Women with BN secrete abnormally low amounts of GLP-1 and PP, possibly because of the adaption to large meals in the form of enlarged gastric capacity and reduced muscle tone in the gastric wall. Attenuated secretion of these gastrointestinal satiety peptides may play a role in the maintenance of bulimic behavior.
Collapse
Affiliation(s)
- Sabine Naessén
- Department of Women's and Children's Health, Division of Obstetrics and Gynecology, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden.
| | | | | | | | | |
Collapse
|
38
|
Abstract
Obesity has increased alarmingly in the United States and is increasing in many countries of the world. Because obesity is an important risk factor for type 2 diabetes and other chronic diseases, it is important to develop approaches to counter the rapid increase in adiposity. One approach is bariatric surgery, the most successful clinical intervention known for treating obesity. Surgery can result in impressive weight loss and improvement of obesity-related comorbidities. Yet the mechanisms responsible for this remarkable effect of surgery remain controversial. It is now clear that caloric restriction, per se, does not explain all the reduction in stored fat mass after surgery. A number of gastrointestinal hormones, including glucagon-like peptide (GLP)-1, peptide YY, oxyntomodulin, GLP-2, glucose-dependent insulinotropic polypeptide, ghrelin, and others, can play roles in energy homeostasis and could be involved in bariatric-surgery-related weight loss and weight loss maintenance. Vagal innervation may play a role. In addition, there may be other yet-uncharacterized factors that could participate. This review discusses the possible roles of these hormonal mechanisms in various types of bariatric surgery to help elucidate some of the potential mechanisms at play in short-term and long-term post-bariatric surgery weight loss. Understanding such mechanisms could lead to new and efficacious means to control or even reduce the epidemic of obesity.
Collapse
Affiliation(s)
- Viorica Ionut
- Diabetes and Obesity Research Institute, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA.
| | | |
Collapse
|
39
|
Abstract
Gastric emptying is the first step in the metabolic endocrine cascade that takes place after food intake. The incretin hormones originating in the gut, particularly GLP-1, exert multiple antihyperglycaemic actions such as enhancement of glucose-dependent insulin secretion, suppression of glucagon secretion, slowing of gastric emptying with an ensuing decrease in food intake and weight loss. From extensive studies in experimental animals and humans we have found that GLP-1 also exerts a motility-inhibiting and antispasmodic effect in the gut that was verified in healthy volunteers and patients with irritable bowel syndrome (IBS). In order to further investigate the effect of GLP-1 in humans, we used the dipeptidyl peptidase-IV resistant GLP-1 analogue ROSE-010, thereby extending its biological activity. A randomized, double-blinded, prospective clinical trial was carried out in order to investigate the effect of two doses of ROSE-010 in 166 patients suffering from pain attacks of IBS. We found that injections of ROSE-010 were twice as effective as placebo in terms of total pain relief response in those affected by pain attacks due to IBS. Our results show that basal physiological research studies can be translated into clinical use. The current pharmaceutical incentive with incretin mimetics, such as GLP-1 analogues and exenatide, is an interesting development that apart from its obvious use in diabetes type 2, may also be useful in terms of gut motility-regulating effects with effects on appetite, food intake and motility disorders that may provide an opportunity to bring about new improvements in medical care.
Collapse
Affiliation(s)
- P M Hellström
- Department of Medical Sciences, Uppsala University, Sweden.
| |
Collapse
|
40
|
Nauck MA. Incretin-based therapies for type 2 diabetes mellitus: properties, functions, and clinical implications. Am J Med 2011; 124:S3-18. [PMID: 21194578 DOI: 10.1016/j.amjmed.2010.11.002] [Citation(s) in RCA: 218] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The incretin hormones, glucose-dependent insulinotropic polypeptide (GIP) and glucagonlike peptide-1 (GLP-1), which are secreted by cells of the gastrointestinal tract in response to meal ingestion, exercise important glucoregulatory effects, including the glucose-dependent potentiation of insulin secretion by pancreatic β-cells. Research on the defective incretin action in type 2 diabetes mellitus suggests that the observed loss of insulinotropic activity may be due primarily to a decreased responsiveness of β-cells to GIP. GLP-1 does retain efficacy, albeit not at physiologic levels. Accordingly, augmentation of GLP-1 is a logical therapeutic strategy to ameliorate this deficiency, although the short metabolic half-life of the native hormone renders direct infusion impractical. GLP-1 receptor agonists that resist degradation by the enzyme dipeptidyl peptidase-4 (DPP-4) and have protracted-action kinetics have been developed, and DPP-4 inhibitors that slow the enzymatic cleavage of native GLP-1 provide alternative approaches to enhancing incretin-mediated glucose control. However, GLP-1 receptor agonists and DPP-4 inhibitors are premised on highly divergent mechanisms of action. DPP-4 is ubiquitously expressed in many tissues and is involved in a wide range of physiologic processes in addition to its physiologic influence on incretin hormone biological activity. GLP-1 receptor agonists provide a pharmacologic level of GLP-1 receptor stimulation, whereas DPP-4 inhibitors appear to increase levels of circulating GLP-1 to within the physiologic range. This article examines the physiology of the incretin system, mechanistic differences between GLP-1 receptor agonists and DPP-4 inhibitors used as glucose-lowering agents in the treatment of type 2 diabetes, and the implications of these differences for treatment. The results of recent head-to-head trials are reviewed, comparing the effects of incretin-based therapies on a range of clinical parameters, including glycemia, β-cell function, weight, and cardiovascular function.
Collapse
Affiliation(s)
- Michael A Nauck
- Bad Lauterberg Diabetes Center, Bad Lauterberg im Harz, Germany.
| |
Collapse
|
41
|
Edholm T, Degerblad M, Grybäck P, Hilsted L, Holst JJ, Jacobsson H, Efendic S, Schmidt PT, Hellström PM. Differential incretin effects of GIP and GLP-1 on gastric emptying, appetite, and insulin-glucose homeostasis. Neurogastroenterol Motil 2010; 22:1191-200, e315. [PMID: 20584260 DOI: 10.1111/j.1365-2982.2010.01554.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are major incretins with important effects on glucoregulatory functions. The aim of this study was to investigate effects of GIP and GLP-1 on gastric emptying and appetite after a mixed meal, and effects on insulin secretion and glucose disposal in humans. METHODS Randomized crossover single-blind study in 17 healthy volunteers receiving GIP (2 or 5 pmol kg(-1) min(-1), n = 8), GLP-1 (0.75 pmol kg(-1) min(-1), n = 9) or NaCl for 180 min with a radionuclide-labeled omelette and fruit punch (370 kcal). Outcome measures were gastric emptying rate, insulinogenic index, hunger, satiety, desire to eat, and prospective food consumption. Blood was analyzed for GIP, GLP-1, glucagon, C-peptide, peptide YY (PYY) and ghrelin. KEY RESULTS Glucose-dependent insulinotropic polypeptide 2 and 5 pmol kg(-1) min(-1) decreased gastric half-emptying time from 128.5 ± 34.0 min in controls to 93.3 ± 6.3 and 85.2 ± 11.0 min (P < 0.05). Glucose-dependent insulinotropic polypeptide 5 pmol kg(-1) min(-1) decreased postprandial glucose (P < 0.001) and insulin (P < 0.05) with increased insulinogenic index. Glucose-dependent insulinotropic polypeptide had no effects on hunger, desire to eat, satiety or prospective consumption. Glucagon-like peptide-1 0.75 pmol kg(-1) min(-1) increased half-emptying time from 76.6 ± 7.6 min to 329.4 ± 71.6 (P < 0.01). Glucagon-like peptide-1 decreased plasma glucose and insulin (both P < 0.05-0.001), and increased insulinogenic index markedly. Hunger, desire to eat and prospective consumption were decreased (P < 0.05), and satiety borderline increased (P < 0.06). CONCLUSION & INFERENCES The incretin effect of GIP and GLP-1 differs as GLP-1 exerts a strong glucoregulatory incretin through inhibition of gastric emptying, which GIP does not. Thus, GLP-1 as incretin mimetic may offer unique benefits in terms of weight loss in treatment of type 2 diabetes.
Collapse
Affiliation(s)
- T Edholm
- Department of Medicine, Karolinska Institutet Solna, Stockholm, Sweden
| | | | | | | | | | | | | | | | | |
Collapse
|
42
|
The incretin pathway as a new therapeutic target for obesity. Maturitas 2010; 67:197-202. [DOI: 10.1016/j.maturitas.2010.06.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2010] [Revised: 05/23/2010] [Accepted: 06/18/2010] [Indexed: 12/20/2022]
|
43
|
Abstract
PURPOSE OF REVIEW To review the role of gut hormones involved in appetite regulation and their potential in the treatment of obesity. RECENT FINDINGS The medical treatment of obesity has been fraught with challenges. With two centrally acting agents having been recently withdrawn from the market, new therapies are required. The gut hormones are especially promising therapeutic targets. This article looks at the interplay between gut and brain which mediates the regulation of appetite and energy expenditure. Some recent developments that point the way towards the future development of gut hormone analogues as treatments for obesity are reviewed. SUMMARY Our understanding of the interaction between gut hormones and the neuronal circuits controlling appetite regulation has made great advances over recent years. This knowledge is essential if these peptides are to become potential obesity therapies, both from an efficacy and safety perspective.
Collapse
Affiliation(s)
- Jaimini Cegla
- Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, UK
| | | | | |
Collapse
|
44
|
Valentino MA, Colon-Gonzalez F, Lin JE, Waldman SA. Current trends in targeting the hormonal regulation of appetite and energy balance to treat obesity. Expert Rev Endocrinol Metab 2010; 5:765-783. [PMID: 21297878 PMCID: PMC3032596 DOI: 10.1586/eem.10.33] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
With the eruption of the obesity pandemic over the past few decades, much research has been devoted to understanding the molecular mechanisms by which the human body regulates energy balance. These studies have revealed several mediators, including gut/pancreatic/adipose hormones and neuropeptides that control both short- and long-term energy balance by regulating appetite and/or metabolism. These endogenous mediators of energy balance have been the focus of many anti-obesity drug-development programs aimed at either amplifying endogenous anorexigenic/lipolytic signaling or blocking endogenous orexigenic/lipogenic signaling. Here, we discuss the efficacy and safety of targeting these pathways for the pharmacologic treatment of obesity.
Collapse
Affiliation(s)
- Michael A Valentino
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 132 South 10th Street, 1170 Main, Philadelphia, PA 19107, USA
| | - Francheska Colon-Gonzalez
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 132 South 10th Street, 1170 Main, Philadelphia, PA 19107, USA
| | - Jieru E Lin
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 132 South 10th Street, 1170 Main, Philadelphia, PA 19107, USA
| | - Scott A Waldman
- Department of Pharmacology and Experimental Therapeutics, Thomas Jefferson University, 132 South 10th Street, 1170 Main, Philadelphia, PA 19107, USA
| |
Collapse
|
45
|
Ochner CN, Gibson C, Shanik M, Goel V, Geliebter A. Changes in neurohormonal gut peptides following bariatric surgery. Int J Obes (Lond) 2010; 35:153-66. [PMID: 20625384 DOI: 10.1038/ijo.2010.132] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The rising prevalence of obesity has reached pandemic proportions, with an associated cost estimated at up to 7% of health expenditures worldwide. Bariatric surgery is currently the only effective long-term treatment for obesity and obesity-related co-morbidities in clinically severely obese patients. However, the precise physiological mechanisms underlying the postsurgical reductions in caloric intake and body weight are poorly comprehended. It has been suggested that changes in hormones involved in hunger, food intake and satiety via the neurohormonal network may contribute to the efficacy of bariatric procedures. In this review, we consider how gastrointestinal hormone concentrations, involved in appetite and body weight regulation via the gut-brain axis, are altered by different bariatric procedures. Special emphasis is placed on neurohormonal changes following Roux-en-Y gastric bypass surgery, which is the most common and effective procedure used today.
Collapse
Affiliation(s)
- C N Ochner
- New York Obesity Research Center, Department of Medicine, St Luke's-Roosevelt Hospital Center, Columbia University College of Physicians and Surgeons, New York, NY 10025, USA.
| | | | | | | | | |
Collapse
|
46
|
Karra E, Yousseif A, Batterham RL. Mechanisms facilitating weight loss and resolution of type 2 diabetes following bariatric surgery. Trends Endocrinol Metab 2010; 21:337-44. [PMID: 20133150 DOI: 10.1016/j.tem.2010.01.006] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2009] [Revised: 12/28/2009] [Accepted: 01/07/2010] [Indexed: 12/25/2022]
Abstract
Bariatric surgery is the most effective treatment modality for obesity, resulting in durable weight loss and amelioration of obesity-associated comorbidities, particularly type 2 diabetes mellitus (T2DM). Moreover, the metabolic benefits of bariatric surgery occur independently of weight loss. There is increasing evidence that surgically induced alterations in circulating gut hormones mediate these beneficial effects of bariatric surgery. Here, we summarise current knowledge on the effects of different bariatric procedures on circulating gut hormone levels. We also discuss the theories that have been put forward to explain the weight loss and T2DM resolution following bariatric surgery. Understanding the mechanisms mediating these beneficial outcomes of bariatric surgery could result in new non-surgical treatment strategies for obesity and T2DM.
Collapse
Affiliation(s)
- Efthimia Karra
- Department of Medicine, University College London, Centre for Obesity Research, 5 University Street, London WC1E 6JJ, United Kingdom
| | | | | |
Collapse
|
47
|
Rüttimann EB, Arnold M, Geary N, Langhans W. GLP-1 antagonism with exendin (9–39) fails to increase spontaneous meal size in rats. Physiol Behav 2010; 100:291-6. [DOI: 10.1016/j.physbeh.2010.02.022] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2009] [Revised: 01/08/2010] [Accepted: 02/24/2010] [Indexed: 10/19/2022]
|
48
|
Halford JCG, Boyland EJ, Blundell JE, Kirkham TC, Harrold JA. Pharmacological management of appetite expression in obesity. Nat Rev Endocrinol 2010; 6:255-69. [PMID: 20234354 DOI: 10.1038/nrendo.2010.19] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
For obese individuals, successful weight loss and maintenance are notoriously difficult. Traditional drug development fails to exploit knowledge of the psychological factors that crucially influence appetite, concentrating instead on restrictive criteria of intake and weight reduction, allied to a mechanistic view of energy regulation. Drugs are under development that may produce beneficial changes in appetite expression in the obese. These currently include glucagon-like peptide-1 analogs such as liraglutide, an amylin analog davalintide, the 5-HT(2C) receptor agonist lorcaserin, the monoamine re-uptake inhibitor tesofensine, and a number of combination therapies such as pramlintide and metreleptin, bupropion and naltrexone, phentermine and topiramate, and bupropion and zonisamide. However, the effects of these treatments on eating behavior remain poorly characterized. Obesity is typically a consequence of overconsumption driven by an individual's natural sensitivity to food stimuli and the pleasure derived from eating. Intuitively, these processes should be effective targets for pharmacotherapy, and behavioral analysis can identify drugs that selectively affect desire to eat, enjoyment of eating, satiation or postmeal satiety. Rational interventions designed specifically to modulate these processes could limit the normally aversive consequences of caloric restriction and maximize an individual's capacity to successfully gain control over their appetite.
Collapse
Affiliation(s)
- Jason C G Halford
- School of Psychology, University of Liverpool, Eleanor Rathbone Building, Bedford Street South, Liverpool L69 7ZA, UK.
| | | | | | | | | |
Collapse
|
49
|
Crespo MA, González Matías LC, Lozano MG, Paz SF, Pérez MR, Gago EV, Ferrer FM. [Gastrointestinal hormones in food intake control]. ACTA ACUST UNITED AC 2010; 56:317-30. [PMID: 19695513 DOI: 10.1016/s1575-0922(09)71946-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 05/25/2009] [Indexed: 12/17/2022]
Abstract
The discovery of gut hormones regulating the energy balance has aroused great interest in the scientific community. Some of these hormones modulate appetite and satiety, acting on the hypothalamus or the solitary tract nucleus in the brainstem. In general, the endocrine signals generated in the gut have direct or indirect (through the autonomous nervous system) anorexigenic effects. Only ghrelin, a gastric hormone, has been consistently associated with the initiation of food intake and is regarded as the main orexigenic signal both in animal models and humans. In this review, we provide a brief description of the major gastrointestinal hormones implicated in the regulation of food intake. Given the increased importance of food intake disturbances, especially obesity, a better understanding of the underlying mechanisms of action of the gastrointestinal hormones might contribute to the development of new molecules that could increase the therapeutic arsenal for treating obesity and its associated comorbidities.
Collapse
Affiliation(s)
- Mayte Alvarez Crespo
- Laboratorio de Endocrinología, Departamento de Biología Funcional y Ciencias de la Salud, Facultad de Biología, Universidad de Vigo, Vigo, Pontevedra, España
| | | | | | | | | | | | | |
Collapse
|
50
|
McIntosh CHS, Widenmaier S, Kim SJ. Pleiotropic actions of the incretin hormones. VITAMINS AND HORMONES 2010; 84:21-79. [PMID: 21094896 DOI: 10.1016/b978-0-12-381517-0.00002-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The insulin secretory response to a meal results largely from glucose stimulation of the pancreatic islets and both direct and indirect (autonomic) glucose-dependent stimulation by incretin hormones released from the gastrointestinal tract. Two incretins, Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), have so far been identified. Localization of the cognate G protein-coupled receptors for GIP and GLP-1 revealed that they are present in numerous tissues in addition to the endocrine pancreas, including the gastrointestinal, cardiovascular, central nervous and autonomic nervous systems (ANSs), adipose tissue, and bone. At these sites, the incretin hormones exert a range of pleiotropic effects, many of which contribute to the integration of processes involved in the regulation of food intake, and nutrient and mineral processing and storage. From detailed studies at the cellular and molecular level, it is also evident that both incretin hormones act via multiple signal transduction pathways that regulate both acute and long-term cell function. Here, we provide an overview of current knowledge relating to the physiological roles of GIP and GLP-1, with specific emphasis on their modes of action on islet hormone secretion, β-cell proliferation and survival, central and autonomic neuronal function, gastrointestinal motility, and glucose and lipid metabolism. However, it is emphasized that despite intensive research on the various body systems, in many cases there is uncertainty as to the pathways by which the incretins mediate their pleiotropic effects and only a rudimentary understanding of the underlying cellular mechanisms involved, and these are challenges for the future.
Collapse
Affiliation(s)
- Christopher H S McIntosh
- Department of Cellular & Physiological Sciences and the Diabetes Research Group, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | |
Collapse
|