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Lau DCW, Erichsen L, Francisco AM, Satylganova A, le Roux CW, McGowan B, Pedersen SD, Pietiläinen KH, Rubino D, Batterham RL. Once-weekly cagrilintide for weight management in people with overweight and obesity: a multicentre, randomised, double-blind, placebo-controlled and active-controlled, dose-finding phase 2 trial. Lancet 2021; 398:2160-2172. [PMID: 34798060 DOI: 10.1016/s0140-6736(21)01751-7] [Citation(s) in RCA: 74] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 07/13/2021] [Accepted: 07/27/2021] [Indexed: 12/17/2022]
Abstract
BACKGROUND Natural amylin is a pancreatic hormone that induces satiety. Cagrilintide is a long-acting amylin analogue under investigation for weight management. We assessed the dose-response relationship of cagrilintide regarding the effects on bodyweight, safety, and tolerability. METHODS We conducted a multicentre, randomised, double-blind, placebo-controlled and active-controlled, dose-finding phase 2 trial at 57 sites including hospitals, specialist clinics, and primary care centres in ten countries (Canada, Denmark, Finland, Ireland, Japan, Poland, Serbia, South Africa, the UK, and the USA). Eligible participants were adults aged at least 18 years without diabetes, with a body-mass index of at least 30 kg/m2 or at least 27 kg/m2 with hypertension or dyslipidaemia. Participants were randomly assigned (6:1) to subcutaneous self-injections of once-weekly cagrilintide (0·3, 0·6, 1·2, 2·4, or 4·5 mg), once-daily liraglutide 3·0 mg, or volume-matched placebo (for six placebo groups). The trial had a 26-week treatment period, including a dose-escalation period of up to 6 weeks, and a 6-week follow-up period without treatment. Participants and investigators were masked to the assigned study treatment with respect to active versus pooled placebo treatment, but not to different active treatments. The primary endpoint was the percentage change in bodyweight from baseline to week 26, assessed in all randomly assigned participants according to the trial product estimand (assuming all participants were adherent to treatment) and to the treatment policy estimand (regardless of adherence to treatment). Safety was assessed in all participants who received at least one dose of randomised treatment. This trial is registered with ClinicalTrials.gov, NCT03856047, and is closed to new participants. FINDINGS Between March 1 and Aug 19, 2019, we randomly assigned 706 participants to cagrilintide 0·3-4·5 mg (100-102 per dose group), 99 to liraglutide 3·0 mg, and 101 to placebo. Permanent treatment discontinuation (n=73 [10%]) occurred similarly across treatment groups, mostly due to adverse events (n=30 [4%]). In total, 29 participants (4%) withdrew from the trial. According to the trial product estimand, mean percentage weight reductions from baseline were greater with all doses of cagrilintide (0·3-4·5 mg, 6·0%-10·8% [6·4-11·5 kg]) versus placebo (3·0% [3·3 kg]; estimated treatment difference range 3·0%-7·8%; p<0·001). Weight reductions were also greater with cagrilintide 4·5 mg versus liraglutide 3·0 mg (10·8% [11·5 kg] vs 9·0% [9·6 kg]; estimated treatment difference 1·8%, p=0·03). Similar weight loss reductions were observed with the treatment policy estimand. The most frequent adverse events were gastrointestinal disorders (eg, nausea, constipation, and diarrhoea) and administration-site reactions. More participants receiving cagrilintide 0·3-4·5 mg had gastrointestinal adverse events compared with placebo (41%-63% vs 32%), primarily nausea (20%-47% vs 18%). INTERPRETATION Treatment with cagrilintide in people with overweight and obesity led to significant reductions in bodyweight and was well tolerated. The findings support the development of molecules with novel mechanisms of action for weight management. FUNDING Novo Nordisk A/S.
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Affiliation(s)
- David C W Lau
- Julia McFarlane Diabetes Research Centre and Libin Cardiovascular Institute of Alberta, University of Calgary Cumming School of Medicine, Calgary, AB, Canada.
| | | | | | | | - Carel W le Roux
- Diabetes Complications Research Centre, University College Dublin, Dublin, Ireland
| | - Barbara McGowan
- Guy's & St Thomas' Hospital, Department of Diabetes and Endocrinology, London, UK
| | - Sue D Pedersen
- C-ENDO Diabetes & Endocrinology Clinic Calgary, Calgary, AB, Canada
| | - Kirsi H Pietiläinen
- Obesity Research Unit, Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Obesity Center, Abdominal Center, Endocrinology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | | | - Rachel L Batterham
- National Institute of Health Research, UCLH Biomedical Research Centre, London, UK; Centre for Obesity Research, Department of Medicine, University College London, London, UK
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Bishoyi AK, Roham PH, Rachineni K, Save S, Hazari MA, Sharma S, Kumar A. Human islet amyloid polypeptide (hIAPP) - a curse in type II diabetes mellitus: insights from structure and toxicity studies. Biol Chem 2020; 402:133-153. [PMID: 33544470 DOI: 10.1515/hsz-2020-0174] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/11/2020] [Indexed: 12/13/2022]
Abstract
The human islet amyloid polypeptide (hIAPP) or amylin, a neuroendocrine peptide hormone, is known to misfold and form amyloidogenic aggregates that have been observed in the pancreas of 90% subjects with Type 2 Diabetes Mellitus (T2DM). Under normal physiological conditions, hIAPP is co-stored and co-secreted with insulin; however, under chronic hyperglycemic conditions associated with T2DM, the overexpression of hIAPP occurs that has been associated with the formation of amyloid deposits; as well as the death and dysfunction of pancreatic β-islets in T2DM. Hitherto, various biophysical and structural studies have shown that during this process of aggregation, the peptide conformation changes from random structure to helix, then to β-sheet, subsequently to cross β-sheets, which finally form left-handed helical aggregates. The intermediates, formed during this process, have been shown to induce higher cytotoxicity in the β-cells by inducing cell membrane disruption, endoplasmic reticulum stress, mitochondrial dysfunction, oxidative stress, islet inflammation, and DNA damage. As a result, several research groups have attempted to target both hIAPP aggregation phenomenon and the destabilization of preformed fibrils as a therapeutic intervention for T2DM management. In this review, we have summarized structural aspects of various forms of hIAPP viz. monomer, oligomers, proto-filaments, and fibrils of hIAPP. Subsequently, cellular toxicity caused by toxic conformations of hIAPP has been elaborated upon. Finally, the need for performing structural and toxicity studies in vivo to fill in the gap between the structural and cellular aspects has been discussed.
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Affiliation(s)
- Ajit Kumar Bishoyi
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Pratiksha H Roham
- Department of Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune, 411007, Maharashtra, India
| | - Kavitha Rachineni
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Shreyada Save
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - M Asrafuddoza Hazari
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
| | - Shilpy Sharma
- Department of Biotechnology, Savitribai Phule Pune University (Formerly University of Pune), Ganeshkhind, Pune, 411007, Maharashtra, India
| | - Ashutosh Kumar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai, 400076, Maharashtra, India
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Raimundo AF, Ferreira S, Martins IC, Menezes R. Islet Amyloid Polypeptide: A Partner in Crime With Aβ in the Pathology of Alzheimer's Disease. Front Mol Neurosci 2020; 13:35. [PMID: 32265649 PMCID: PMC7103646 DOI: 10.3389/fnmol.2020.00035] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 02/20/2020] [Indexed: 12/14/2022] Open
Abstract
Diabetes affects hundreds of millions of patients worldwide. Despite the advances in understanding the disease and therapeutic options, it remains a leading cause of death and of comorbidities globally. Islet amyloid polypeptide (IAPP), or amylin, is a hormone produced by pancreatic β-cells. It contributes to the maintenance of glucose physiological levels namely by inhibiting insulin and glucagon secretion as well as controlling adiposity and satiation. IAPP is a highly amyloidogenic polypeptide forming intracellular aggregates and amyloid structures that are associated with β-cell death. Data also suggest the relevance of unprocessed IAPP forms as seeding for amyloid buildup. Besides the known consequences of hyperamylinemia in the pancreas, evidence has also pointed out that IAPP has a pathological role in cognitive function. More specifically, IAPP was shown to impair the blood–brain barrier; it was also seen to interact and co-deposit with amyloid beta peptide (Aß), and possibly with Tau, within the brain of Alzheimer's disease (AD) patients, thereby contributing to diabetes-associated dementia. In fact, it has been suggested that AD results from a metabolic dysfunction in the brain, leading to its proposed designation as type 3 diabetes. Here, we have first provided a brief perspective on the IAPP amyloidogenic process and its role in diabetes and AD. We have then discussed the potential interventions for modulating IAPP proteotoxicity that can be explored for therapeutics. Finally, we have proposed the concept of a “diabetes brain phenotype” hypothesis in AD, which may help design future IAPP-centered drug developmentstrategies against AD.
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Affiliation(s)
- Ana F Raimundo
- iBET - Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.,CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal.,ITQB-NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
| | - Sofia Ferreira
- iBET - Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.,CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Ivo C Martins
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Regina Menezes
- iBET - Instituto de Biologia Experimental e Tecnológica, Oeiras, Portugal.,CEDOC - Chronic Diseases Research Center, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal.,ITQB-NOVA, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Oeiras, Portugal
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Ling W, Huang YM, Qiao YC, Zhang XX, Zhao HL. Human Amylin: From Pathology to Physiology and Pharmacology. Curr Protein Pept Sci 2019; 20:944-957. [DOI: 10.2174/1389203720666190328111833] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Revised: 03/12/2019] [Accepted: 03/15/2019] [Indexed: 12/18/2022]
Abstract
The histopathological hallmark of type 2 diabetes is islet amyloid implicated in the developing treatment options. The major component of human islet amyloid is 37 amino acid peptide known as amylin or islet amyloid polypeptide (IAPP). Amylin is an important hormone that is co-localized, copackaged, and co-secreted with insulin from islet β cells. Physiologically, amylin regulates glucose homeostasis by inhibiting insulin and glucagon secretion. Furthermore, amylin modulates satiety and inhibits gastric emptying via the central nervous system. Normally, human IAPP is soluble and natively unfolded in its monomeric state. Pathologically, human IAPP has a propensity to form oligomers and aggregate. The oligomers show misfolded α-helix conformation and can further convert themselves to β-sheet-rich fibrils as amyloid deposits. The pathological findings and physiological functions of amylin have led to the introduction of pramlintide, an amylin analog, for the treatment of diabetes. The history of amylin’s discovery is a representative example of how a pathological finding can translate into physiological exploration and lead to pharmacological intervention. Understanding the importance of transitioning from pathology to physiology and pharmacology can provide novel insight into diabetes mellitus and Alzheimer's disease.
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Affiliation(s)
- Wei Ling
- Center for Diabetic Systems Medicine, Guangxi Key Laboratory of Excellence, Guilin Medical University, Guilin 541004, China
| | - Yan-Mei Huang
- Center for Diabetic Systems Medicine, Guangxi Key Laboratory of Excellence, Guilin Medical University, Guilin 541004, China
| | - Yong-Chao Qiao
- Department of Laboratory, the Affiliated Hospital of Guilin Medical University, Guilin 541004, China
| | - Xiao-Xi Zhang
- Center for Diabetic Systems Medicine, Guangxi Key Laboratory of Excellence, Guilin Medical University, Guilin 541004, China
| | - Hai-Lu Zhao
- Center for Diabetic Systems Medicine, Guangxi Key Laboratory of Excellence, Guilin Medical University, Guilin 541004, China
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Press M, Jung T, König J, Grune T, Höhn A. Protein aggregates and proteostasis in aging: Amylin and β-cell function. Mech Ageing Dev 2018; 177:46-54. [PMID: 29580826 DOI: 10.1016/j.mad.2018.03.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 03/22/2018] [Indexed: 01/07/2023]
Abstract
The ubiquitin-proteasomal-system (UPS) and the autophagy-lysosomal-system (ALS) are both highly susceptible for disturbances leading to the accumulation of cellular damage. A decline of protein degradation during aging results in the formation of oxidatively damaged and aggregated proteins finally resulting in failure of cellular functionality. Besides protein aggregation in response to oxidative damage, amyloids are a different type of protein aggregates able to distract proteostasis and interfere with cellular functionality. Amyloids are clearly linked to the pathogenesis of age-related degenerative diseases such as Alzheimer's disease. Human amylin is one of the peptides forming fibrils in β-sheet conformation finally leading to amyloid formation. In contrast to rodent amylin, human amylin is prone to form amyloidogenic aggregates, proposed to play a role in the pathogenesis of Type 2 Diabetes by impairing β-cell functionality. Since aggregates such as lipofuscin and β-amyloid are known to impair proteostasis, it is likely to assume similar effects for human amylin. In this review, we focus on the effects of IAPP on UPS and ALS and their role in amylin degradation, since both systems play a crucial role in maintaining proteome balance thereby influencing, at least in part, cellular fate and aging.
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Affiliation(s)
- Michaela Press
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany.
| | - Tobias Jung
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Cardiovascular Research (DZHK), 10117 Berlin, Germany.
| | - Jeannette König
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany.
| | - Tilman Grune
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany; German Center for Cardiovascular Research (DZHK), 10117 Berlin, Germany; NutriAct - Competence Cluster Nutrition Research Berlin-Potsdam, 14558 Nuthetal, Germany; Institute of Nutrition, University of Potsdam, 14558 Nuthetal, Germany.
| | - Annika Höhn
- Department of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke (DIfE), 14558 Nuthetal, Germany; German Center for Diabetes Research (DZD), 85764 Muenchen-Neuherberg, Germany.
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Zhang XX, Pan YH, Huang YM, Zhao HL. Neuroendocrine hormone amylin in diabetes. World J Diabetes 2016; 7:189-97. [PMID: 27162583 PMCID: PMC4856891 DOI: 10.4239/wjd.v7.i9.189] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/16/2016] [Accepted: 04/05/2016] [Indexed: 02/05/2023] Open
Abstract
The neuroendocrine hormone amylin, also known as islet amyloid polypeptide, is co-localized, co-packaged and co-secreted with insulin from adult pancreatic islet β cells to maintain glucose homeostasis. Specifically, amylin reduces secretion of nutrient-stimulated glucagon, regulates blood pressure with an effect on renin-angiotensin system, and delays gastric emptying. The physiological actions of human amylin attribute to the conformational α-helix monomers whereas the misfolding instable oligomers may be detrimental to the islet β cells and further transform to β-sheet fibrils as amyloid deposits. No direct evidence proves that the amylin fibrils in amyloid deposits cause diabetes. Here we also have performed a systematic review of human amylin gene changes and reported the S20G mutation is minor in the development of diabetes. In addition to the metabolic effects, human amylin may modulate autoimmunity and innate inflammation through regulatory T cells to impact on both human type 1 and type 2 diabetes.
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Oosterlinck W, Herijgers P. Cardiomyocyte changes in the metabolic syndrome and implications for endogeneous protective strategies. Expert Rev Cardiovasc Ther 2014; 12:331-43. [DOI: 10.1586/14779072.2014.893825] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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PPARγ as a therapeutic target in diabetic nephropathy and other renal diseases. Curr Opin Nephrol Hypertens 2012; 21:97-105. [PMID: 22143250 DOI: 10.1097/mnh.0b013e32834de526] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
PURPOSE OF REVIEW Peroxisome proliferator-activated receptor gamma (PPARγ) is a ligand-activated nuclear transcription factor that regulates many important physiological processes including glucose and lipid metabolism, energy homeostasis, cell proliferation, inflammation, immunity and reproduction. The current review aims to summarize and discuss recent findings evaluating the protective effects of PPARγ against kidney diseases with a focus on diabetic nephropathy. We will also delineate the potential underlying mechanisms. RECENT FINDINGS PPARγ plays important roles in renal physiology and pathophysiology. Agonists of PPARγ exert protective effects against various kidney diseases including diabetic nephropathy, ischemic renal injury, IgA nephropathy, chemotherapy-associated kidney damage, polycystic kidney diseases and age-related kidney diseases via both systemic and renal actions. SUMMARY PPARγ agonists are effective in delaying and even preventing the progression of many renal diseases, especially diabetic nephropathy. PPARγ may represent a promising target for the treatment of renal diseases.
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Hayden MR, Sowers KM, Pulakat L, Joginpally T, Krueger B, Whaley-Connell A, Sowers JR. Possible Mechanisms of Local Tissue Renin-Angiotensin System Activation in the Cardiorenal Metabolic Syndrome and Type 2 Diabetes Mellitus. Cardiorenal Med 2011; 1:193-210. [PMID: 22096455 DOI: 10.1159/000329926] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2011] [Accepted: 06/07/2011] [Indexed: 01/08/2023] Open
Abstract
The role of local tissue renin-angiotensin system (tRAS) activation in the cardiorenal metabolic syndrome (CRS) and type 2 diabetes mellitus (T2DM) is not well understood. To this point, we posit that early redox stress-mediated injury to tissues and organs via accumulation of excessive reactive oxygen species (ROS) and associated wound healing responses might serve as a paradigm to better understand how tRAS is involved. There are at least five common categories responsible for generating ROS that may result in a positive feedback ROS-tRAS axis. These mechanisms include metabolic substrate excess, hormonal excess, hypoxia-ischemia/reperfusion, trauma, and inflammation. Because ROS are toxic to proteins, lipids, and nucleic acids they may be the primary instigator, serving as the injury nidus to initiate the wound healing process. Insulin resistance is central to the development of the CRS and T2DM, and there are now thought to be four major organ systems important in their development. In states of overnutrition and tRAS activation, adipose tissue, skeletal muscle (SkM), islet tissues, and liver (the quadrumvirate) are individually and synergistically related to the development of insulin resistance, CRS, and T2DM. The obesity epidemic is thought to be the driving force behind the CRS and T2DM, which results in the impairment of multiple end-organs, including the cardiovascular system, pancreas, kidney, retina, liver, adipose tissue, SkM, and nervous system. A better understanding of the complex mechanisms leading to local tRAS activation and increases in tissue ROS may lead to new therapies emphasizing global risk reduction of ROS resulting in decreased morbidity and mortality.
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Affiliation(s)
- Melvin R Hayden
- Department of Internal Medicine, University of Missouri-Columbia School of Medicine, Columbia, Mo., USA
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Abstract
Gut microbiota is an assortment of microorganisms inhabiting the length and width of the mammalian gastrointestinal tract. The composition of this microbial community is host specific, evolving throughout an individual's lifetime and susceptible to both exogenous and endogenous modifications. Recent renewed interest in the structure and function of this "organ" has illuminated its central position in health and disease. The microbiota is intimately involved in numerous aspects of normal host physiology, from nutritional status to behavior and stress response. Additionally, they can be a central or a contributing cause of many diseases, affecting both near and far organ systems. The overall balance in the composition of the gut microbial community, as well as the presence or absence of key species capable of effecting specific responses, is important in ensuring homeostasis or lack thereof at the intestinal mucosa and beyond. The mechanisms through which microbiota exerts its beneficial or detrimental influences remain largely undefined, but include elaboration of signaling molecules and recognition of bacterial epitopes by both intestinal epithelial and mucosal immune cells. The advances in modeling and analysis of gut microbiota will further our knowledge of their role in health and disease, allowing customization of existing and future therapeutic and prophylactic modalities.
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Affiliation(s)
- Inna Sekirov
- Michael Smith Laboratories, Department of Microbiology and Immunology, The University of British Columbia, Vancouver, British Columbia, Canada
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James S, Moralez J, Nagamani M. Increased secretion of amylin in women with polycystic ovary syndrome. Fertil Steril 2009; 94:211-5. [PMID: 19338997 DOI: 10.1016/j.fertnstert.2009.02.086] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 02/25/2009] [Accepted: 02/25/2009] [Indexed: 10/21/2022]
Abstract
OBJECTIVE To investigate amylin secretion in women with polycystic ovary syndrome (PCOS). DESIGN Prospective, case-control study. SETTING Academic institution. PATIENT(S) Twenty women with PCOS and 10 with ovulatory cycles who matched for body mass index. INTERVENTION(S) An oral glucose tolerance test was performed, and glucose, insulin, and amylin levels were measured at fasting and after glucose ingestion. The area under the curve for insulin, amylin, and glucose was calculated. Ten women with PCOS were treated with metformin and 10 women with rosiglitazone for 6 months. Amylin levels were measured before and after treatment. RESULT(S) Fasting amylin levels and amylin response to oral glucose were significantly increased in women with PCOS. At fasting, there was significant positive correlation between insulin and amylin levels both in women with PCOS and control subjects. After glucose ingestion, amylin response correlated with the glucose response in women with PCOS. Amylin levels decreased with metformin but not with rosiglitazone treatment. CONCLUSION(S) In women with PCOS, [1] there is increased secretion of amylin, [2] insulin and amylin secretion is coregulated in the fasting state, [3] after glucose ingestion, glucose levels regulate amylin release, and [4] the insulin-sensitizing agent metformin, but not rosiglitazone, reduces amylin secretion.
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Affiliation(s)
- Summer James
- Division of Reproductive Endocrinology, Department of Obstetrics and Gynecology, University of Texas Medical Branch, Galveston, Texas 77555-0587, USA
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Role of PPARgamma in renoprotection in Type 2 diabetes: molecular mechanisms and therapeutic potential. Clin Sci (Lond) 2009; 116:17-26. [PMID: 19037881 DOI: 10.1042/cs20070462] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
DN (diabetic nephropathy) is a chronic disease characterized by proteinuria, glomerular hypertrophy, decreased glomerular filtration and renal fibrosis with loss of renal function. DN is the leading cause of ESRD (end-stage renal disease), accounting for millions of deaths worldwide. TZDs (thiazolidinediones) are synthetic ligands of PPARgamma (peroxisome-proliferator-activated receptor gamma), which is involved in many important physiological processes, including adipose differentiation, lipid and glucose metabolism, energy homoeostasis, cell proliferation, inflammation, reproduction and renoprotection. A large body of research over the past decade has revealed that, in addition to their insulin-sensitizing effects, TZDs play an important role in delaying and preventing the progression of chronic kidney disease in Type 2 diabetes. Although PPARgamma activation by TZDs is in general considered beneficial for the amelioration of diabetic renal complications in Type 2 diabetes, the underlying mechanism(s) remains only partially characterized. In this review, we summarize and discuss recent findings regarding the renoprotective effects of PPARgamma in Type 2 diabetes and the potential underlying mechanisms.
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Michell A, Debnam E, Unwin R. Regulation of Renal Function by the Gastrointestinal Tract: Potential Role of Gut-Derived Peptides and Hormones. Annu Rev Physiol 2008; 70:379-403. [DOI: 10.1146/annurev.physiol.69.040705.141330] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- A.R. Michell
- Department of Biochemical Pharmacology, William Harvey Research Institute, St. Bartholomew's Hospital Medical School, London EC1M 6BQ, United Kingdom;
| | - E.S. Debnam
- Department of Physiology, Royal Free and University College Medical School, London NW3 2PF, United Kingdom;
| | - R.J. Unwin
- Department of Physiology, Royal Free and University College Medical School, London NW3 2PF, United Kingdom;
- Centre for Nephrology, Royal Free and University College Medical School, London NW3 2PF, United Kingdom;
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Samonina G, Kopylova G, Lukjanzeva G, Zhuykova S, Smirnova E, German S, Guseva A. Antiulcer effects of amylin: a review. PATHOPHYSIOLOGY 2004; 11:1-6. [PMID: 15177509 DOI: 10.1016/j.pathophys.2003.10.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2002] [Accepted: 10/09/2003] [Indexed: 01/22/2023] Open
Abstract
Amylin belongs to the calcitonin peptide family. Amylin is a peptide synthesized not only in the beta cells of pancreatic islets, but in small quantities also in other organs like in the intestinal and gastric mucosa, lungs and central nervous system. It is located in the same secretory granules as insulin. Amylin participates in the maintenance of glucose and calcium homeostasis. It also inhibits food intake and decreases body weight. Furthermore, amylin inhibits gastric acid secretion. It protects the gastric mucosa in ulcer models like stress, vagal stimulation, ethanol, acetic acid, reserpine and serotonine administration and pylorus ligation. This protective antiulcer is seen not only at pharmacological but also at near-physiological doses-0.5mkg/kg. Moreover amylin also exerts curative properties in the acetic acid and indomethacin ulcer models. Amylin decreases the aggressive factors like acid-pepsin secretion, increases mast cell stability and increases protective mechanisms like bicarbonate gastric secretion, dilates blood vessels, and it increases lymphatic mesenteric activity. Amylin seems to be a powerful protector of gastric mucosa in animals by increasing the stability of gastric mucosa. Further research remains, however, to be done.
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Affiliation(s)
- G.E. Samonina
- Department of Human and Animal Physiology, School of Biology, Moscow State Lomonosov University, Vorobjevy Gory 1, Building 12, Moscow 119899, Russia
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Kailasam MT, Parmer RJ, Tyrell EA, Henry RR, O'Connor DT. Circulating amylin in human essential hypertension: heritability and early increase in individuals at genetic risk. J Hypertens 2000; 18:1611-20. [PMID: 11081774 DOI: 10.1097/00004872-200018110-00012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Human essential hypertension is a complex trait with poorly understood genetic determination. Insulin resistance is frequently associated with this trait. OBJECTIVE To determine whether a potentially pathogenic feature of the insulin-resistant state, circulating amylin (islet amyloid polypeptide, co-released with insulin from pancreatic islet beta-cells), is already increased in prehypertensive individuals (normotensive persons at genetic risk of hypertension because of family history), whether such individuals already differ in their amylin response to beta-cell stimulation, and whether plasma amylin concentration is heritable. Such features could establish increased circulating amylin as a hereditary 'intermediate phenotype' useful in genetic analyses of hypertension. METHODS Plasma amylin and insulin were measured in 283 medication-free individuals stratified by blood pressure status (82 hypertensive and 201 normotensive), and genetic risk (family history) of hypertension. Differences in means were tested by ANOVA, variances by F test, and frequency distributions by maximum likelihood analysis. Co-release of amylin and insulin was provoked by intravenous infusion of mixed amino acids. The effect of antihypertensive treatment was evaluated after monotherapy with either angiotensin converting enzyme inhibition or calcium-channel blockade in hypertension. RESULTS Plasma amylin was increased in hypertension (P= 0.027), and body mass index was a strong predictor of increased circulating amylin (P = 0.0001). Plasma amylin and plasma renin activity were not correlated (P = 0.395), and effective antihypertensive monotherapy with either angiotensin converting enzyme inhibition or calcium-channel blockade did not affect either amylin (P = 0.87-0.97) or insulin (P= 0.55-0.59). Among normotensive individuals, those at genetic risk of hypertension (with positive family history) already had increased concentrations of amylin (P< 0.001), despite exhibiting no difference in blood pressure or body mass index compared with the family-history-negative group; however, among normotensive individuals, both family history (P = 0.043) and body mass index (P= 0.0059) were significant predictors of increased concentrations of amylin. By maximum likelihood analysis, plasma amylin was distributed heterogeneously in the normotensive individuals, with two modes best explaining the distribution (chi2 = 77.4, P< 0.001), and family-history-positive individuals completely accounting for the upper mode (chi2 = 4.63, P = 0.031). Family-history-positive normotensive individuals showed greater plasma amylin concentrations both before and during beta-cell stimulation by amino acid infusion (P = 0.014). Black (n = 111) and white (n = 172) individuals did not differ in mean (P = 0.946) or variance (P = 0.172) of plasma amylin concentrations. CONCLUSIONS These results suggest that plasma amylin concentration is in part determined by heredity. Both basal and stimulated plasma amylin excess may identify a subgroup of individuals bearing an inherited predisposition to hypertension. Measurement of amylin might identify a useful 'intermediate phenotype' in the genetic analysis of essential hypertension and its relationship to insulin resistance.
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Affiliation(s)
- M T Kailasam
- Department of Medicine and Center for Molecular Genetics, University of California and VA San Diego Healthcare System, 92161, USA
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Giacchetti G, Sechi LA, Griffin CA, Don BR, Mantero F, Schambelan M. The tissue renin-angiotensin system in rats with fructose-induced hypertension: overexpression of type 1 angiotensin II receptor in adipose tissue. J Hypertens 2000; 18:695-702. [PMID: 10872553 DOI: 10.1097/00004872-200018060-00006] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE Fructose feeding induces hypertension, insulin-resistance and hypertriglyceridemia in Sprague-Dawley rats. The mechanisms of fructose-induced hypertension are as yet unknown. Here we investigate the effects of fructose feeding and of varying salt intake on blood pressure, glucose tolerance, plasma renin activity, and tissue angiotensinogen, renin, and AT1 receptor mRNA levels in this model of hypertension. DESIGN AND METHODS To investigate the role of the renin-angiotensin system in fructose-induced hypertension we measured angiotensinogen, renin and angiotensin II type 1 (AT1) receptor mRNA levels in tissues of Sprague-Dawley rats that were fed either standard rat chow or a diet containing 66% fructose. RESULTS Blood pressure (P < 0.05) and triglyceride (P < 0.01) levels were significantly greater in the fructose-fed animals. Plasma glucose and insulin responses to an oral glucose load were significantly greater (P< 0.05) in fructose-fed than control rats. Angiotensinogen mRNA levels in liver and fat, and renin mRNA levels in kidney did not differ between fructose-fed and control animals. Levels of AT1 receptor mRNA were significantly greater in the fat obtained from fructose-fed rats than in that from control rats (P< 0.05), but this was not so in the kidney. To determine whether fructose-induced hypertension is dependent on dietary salt content, rats were fed standard rat chow and a fructose-enriched diet with low and high sodium chloride concentrations. Blood pressure increased significantly (P< 0.05) only in the fructose-fed rats receiving the high-salt diet Similarly, increased AT1 receptor mRNA levels were observed only in the fructose-fed rats that were maintained on the high-salt diet CONCLUSIONS Fructose feeding induces hypertension in normal- or high-salt fed animals and it is associated with an increased expression of the AT1 receptor in adipose tissue. These findings suggest that AT1 receptors might play a role in the pathophysiology of metabolic and hemodynamic abnormalities induced by fructose feeding.
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Affiliation(s)
- G Giacchetti
- Division of Endocrinology, University of Ancona, Ospedale 'Umberto l'Torrette, Italy.
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