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Preparation of a new type 2 diabetic miniature pig model via the CRISPR/Cas9 system. Cell Death Dis 2019; 10:823. [PMID: 31659151 PMCID: PMC6817862 DOI: 10.1038/s41419-019-2056-5] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 09/24/2019] [Accepted: 10/11/2019] [Indexed: 12/25/2022]
Abstract
Diabetes has become one of the major noninfectious diseases that seriously endanger public health. The formation of islet amyloid polypeptide (IAPP) affects the normal physiological functions of the body, such as glucose metabolism and lipid metabolism. The mature human IAPP protein (hIAPP) has a strong tendency to misfold and is considered to be one of the major causes of amyloid changes in islets. Deposition of hIAPP is considered to be one of the leading causes of type 2 diabetes mellitus (T2DM). Miniature pigs are experimental animal models that are well suited for research on gene function and human diabetes. In our study, we obtained IAPP gene-humanized miniature pigs via the CRISPR/Cas9 system and somatic cell nuclear transfer (SCNT) technology. The hIAPP pigs can be used to further study the pathogenesis and related complications of T2DM and to lay a solid foundation for the prevention and treatment of T2DM.
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Abstract
OBJECTIVE Deposition of cell toxic islet amyloid is a frequent finding in type 2 diabetes and also in transplanted human islets, where it is a possible explanation for their long-term failure. One suggested reason for amyloid in transplanted islets is that their low vascular density results in a disturbed local clearance of islet amyloid polypeptide (IAPP). To test this hypothesis we analysed accumulation of amyloid in microencapsulated islets, which exemplify a non-vascularised islet graft. METHODS Isolated islets from human or transgenic mice expressing human IAPP were microencapsulated in alginate and cultured in vitro or transplanted under the kidney capsule of normoglycemic nude mice. The degree of amyloid was determined after Congo red staining and subcellular alterations were analysed with electron microscopy. RESULTS Insulin and IAPP secretion from transgenic mouse islets were markedly increased during stimulation with glucose after one week of culture, but encapsulated islets in general released less insulin. Amyloid was detected after both one and three weeks of culture in the transgenic mouse islets and the encapsulated islets were most affected. After transplantation, electron microscopy displayed both intra- and extracellular amyloid in microencapsulated as well as in non-encapsulated human and transgenic mouse islet grafts. However, amyloid was more frequent in the encapsulated grafts. CONCLUSION Micro-encapsulation of pancreatic islets might serve as an important tool for studies of amyloid formation under enhanced circumstances.
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Affiliation(s)
- Sara Bohman
- Department of Medical Cell Biology, Uppsala University, Sweden
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Transthyretin and amyloid in the islets of Langerhans in type-2 diabetes. EXPERIMENTAL DIABETES RESEARCH 2008; 2008:429274. [PMID: 18825272 PMCID: PMC2553203 DOI: 10.1155/2008/429274] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Revised: 05/07/2008] [Accepted: 07/03/2008] [Indexed: 11/20/2022]
Abstract
Transthyretin (TTR) is a major amyloid fibril protein in certain systemic forms of amyloidosis. It is a plasma protein, mainly synthesized by the liver but expression occurs also at certain minor locations, including the endocrine cells in the islets of Langerhans. With the use of immunohistochemistry and in situ hybridization, we have studied the distribution of transthyretin-containing cells in islets of Langerhans in type-2 diabetic and nondiabetic individuals. TTR expression was particularly seen in alpha (glucagon) cells. Islets from type-2 diabetic patients had proportionally more transthyretin-reactive islet cells, including beta cells. A weak transthyretin immunoreaction in IAPP-derived amyloid occurred in some specimens. In seeding experiments in vitro, we found that TTR fibrils did not seed IAPP while IAPP fibrils seeded TTR. It is suggested that islet expression of transthyretin may be altered in type-2 diabetes.
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Paulsson JF, Westermark GT. Aberrant processing of human proislet amyloid polypeptide results in increased amyloid formation. Diabetes 2005; 54:2117-25. [PMID: 15983213 DOI: 10.2337/diabetes.54.7.2117] [Citation(s) in RCA: 98] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The amyloid present in the islets of Langerhans in type 2 diabetes is polymerized islet amyloid polypeptide (IAPP). The precursor protein proIAPP is posttranslationally modified, a process involving the removal of NH2- and COOH-terminal flanking peptides. This step is performed by the prohormone convertases PC2 and PC1/3. PC2 processes proIAPP preferably at the NH2-terminal processing site, and PC1/3 processes proIAPP exclusively at the COOH-terminal site. Little is known regarding the exact circumstances leading to islet amyloid formation. In this study, we have examined the possible significance of aberrant processing of proIAPP on amyloid formation in several in vitro cellular systems. In our studies, human (h)-proIAPP was transfected into beta-TC-6 cells expressing both prohormone convertases and in which proIAPP is processed into IAPP. Additionally, h-proIAPP was transfected into three different pituitary-derived cell lines with different prohormone convertase profiles: AtT-20 cells (deficient in PC2), GH3 cells (deficient in PC1/3), and GH4C1 cells (deficient in both convertases). We followed the processing of h-proIAPP with antibodies specific for the respective cleavage sites and stained the cells with Congo red to verify the accumulation of amyloid. Incomplete processing of h-proIAPP that occurs in AtT-20 and GH4C1 cells resulted in the formation of intracellular amyloid. No amyloid developed in beta-TC-6 and GH3 cells lines with full processing of proIAPP. An intracellular increase in proIAPP and/or its metabolic products may thus promote intracellular amyloid formation, thereby causing cell death. When extracellularly exposed, this amyloid might act as template for continuing amyloid formation from processed IAPP released from the surrounding beta-cells.
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Affiliation(s)
- Johan F Paulsson
- Deparment of Biomedicine and Surgery, Division of Cell Biology, Linköping University, SE 581 85 Linköping, Sweden
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Affiliation(s)
- Andrew Young
- Amylin Pharmaceuticals, Inc., San Diego, California, USA
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Alvarsson M, Sundkvist G, Lager I, Henricsson M, Berntorp K, Fernqvist-Forbes E, Steen L, Westermark G, Westermark P, Orn T, Grill V. Beneficial effects of insulin versus sulphonylurea on insulin secretion and metabolic control in recently diagnosed type 2 diabetic patients. Diabetes Care 2003; 26:2231-7. [PMID: 12882841 DOI: 10.2337/diacare.26.8.2231] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVE To evaluate whether treatment with insulin in recently diagnosed type 2 diabetes is advantageous compared with glibenclamide treatment. RESEARCH DESIGN AND METHODS Beta-cell function, glycemic control, and quality of life were monitored over 2 years in 39 patients with islet cell antibody-negative type 2 diabetes diagnosed 0-2 years before inclusion in a Swedish multicenter randomized clinical trial. Patients were randomized to either two daily injections of premixed 30% soluble and 70% NPH insulin or glibenclamide (3.5-10.5 mg daily). C-peptide-glucagon tests were performed yearly in duplicate after 2-3 days of temporary withdrawal of treatment. RESULTS After 1 year the glucagon-stimulated C-peptide response was increased in the insulin-treated group by 0.14 +/- 0.08 nmol/l, whereas it was decreased by 0.12 +/- 0.08 nmol/l in the glibenclamide group, P < 0.02 for difference between groups. After 2 years, fasting insulin levels were higher after treatment withdrawal in the insulin-treated versus the glibenclamide-treated group (P = 0.02). HbA(1c) levels decreased significantly during the first year in both groups; however, at the end of the second year, HbA(1c) had deteriorated in the glibenclamide group (P < 0.01), but not in the insulin-treated group. The difference in evolution of HbA(1c) during the second year was significant between groups, P < 0.02. A questionnaire indicated no difference in well-being related to treatment. CONCLUSIONS Early insulin versus glibenclamide treatment in type 2 diabetes temporarily prolongs endogenous insulin secretion and promotes better metabolic control.
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Affiliation(s)
- Michael Alvarsson
- Department of Endocrinology and Diabetology, Karolinska Hospital, Stockholm, Sweden.
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Ma Z, Westermark GT. Effects of Free Fatty Acid on Polymerization of Islet Amyloid Polypeptide (IAPP) In Vitro and on Amyloid Fibril Formation in Cultivated Isolated Islets of Transgenic Mice Overexpressing Human IAPP. Mol Med 2002. [DOI: 10.1007/bf03402092] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Westermark GT, Falkmer S, Steiner DF, Chan SJ, Engström U, Westermark P. Islet amyloid polypeptide is expressed in the pancreatic islet parenchyma of the teleostean fish, Myoxocephalus (cottus) scorpius. Comp Biochem Physiol B Biochem Mol Biol 2002; 133:119-25. [PMID: 12223219 DOI: 10.1016/s1096-4959(02)00113-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The comparative endocrinology of the 37-amino-acid-residue islet amyloid polypeptide (IAPP) is poorly known, possibly due to the fact that available antisera, raised against mammalian IAPP, fail to give immunoreactivity with islet parenchymal cells of non-mammalian vertebrates. Using reverse transcriptase-linked polymerase chain reaction with degenerate primers, IAPP was identified, and its deduced amino-acid sequence partially characterized, in three species of teleostean fish, i.e. Danio rerio (zebrafish), Salmo salar (Atlantic salmon), and Myoxocephalus (cottus) scorpius (daddy sculpin). The daddy sculpin is a species where the histophysiology of the pancreatic islet parenchyma has previously been comprehensively studied. From the deduced amino-acid sequence, a synthetic peptide, corresponding to positions 20-29 of Salmo IAPP, was synthesized. A mouse antiserum to this peptide gave a distinct immunoreactivity with the insulin-producing beta cells of the sculpin Brockmann bodies and salmon endocrine pancreas. Thus, IAPP belongs to the group of peptide hormones expressed by the islet parenchymal cells in both mammals and non-mammalian vertebrates. Salmo salar IAPP(20-29) was found to give rise to amyloid-like fibrils in vitro.
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Cooper GJS. Amylin and Related Proteins: Physiology and Pathophysiology. Compr Physiol 2001. [DOI: 10.1002/cphy.cp070210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Mesfin FB, Andersen TT, Jacobson HI, Zhu S, Bennett JA. Development of a synthetic cyclized peptide derived from alpha-fetoprotein that prevents the growth of human breast cancer. THE JOURNAL OF PEPTIDE RESEARCH : OFFICIAL JOURNAL OF THE AMERICAN PEPTIDE SOCIETY 2001; 58:246-56. [PMID: 11576331 DOI: 10.1034/j.1399-3011.2001.00922.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The peptide, EMTPVNPG, derived from alpha-fetoprotein, inhibits estrogen-stimulated growth of immature mouse uterus and estrogen-dependent proliferation of human breast cancer cells. However, the biological activities of the peptide diminish over time in storage, even when in the lyophilized state, probably because of peptide aggregation through hydrophobic interaction among monomers. Two analogs of EMTPVNPG were designed with the intent of minimizing aggregation and retaining biological activity during prolonged storage. EMTOVNOG, where O is 4-hydroxyproline, is a linear peptide generated by substituting 4-hydroxyproline for the two prolines, thereby increasing peptide hydrophilicity. This analog exhibited a dose-dependent inhibition of estrogen-stimulated growth of immature mouse uterus similar to that of EMTPVNPG (maximal activity at 1 microg/mouse). A second analog, cyclo-(EMTOVNOGQ), a hydrophilic, cyclic analog with increased conformational constraint, was as potent as the other peptides in its inhibition of estrogen-dependent growth of immature mouse uterus, and had an expanded effective dose range. Both linear and cyclized hydroxyproline-substituted analogs exhibited indefinite shelf-life. Furthermore, both analogs inhibited the estrogen-dependent growth of MCF-7 human breast cancer growing as a xenograft in SCID mice. These analogs may become significant, novel agents for the treatment of breast cancer.
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Affiliation(s)
- F B Mesfin
- Center for Immunology and Microbial Diseases, Albany Medical College, Albany 12208, USA
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Ma Z, Westermark P, Westermark GT. Amyloid in human islets of Langerhans: immunologic evidence that islet amyloid polypeptide is modified in amyloidogenesis. Pancreas 2000; 21:212-8. [PMID: 10975716 DOI: 10.1097/00006676-200008000-00015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Amyloid derived from the beta-cell product islet amyloid polypeptide (IAPP) has been implicated for a beta-cell lesion in Type II diabetes mellitus. The pathogenesis of islet amyloid is poorly understood, and in addition to an amyloidogenic IAPP molecule and possibly increased concentration of IAPP, other unknown factors seem to be included. It was shown previously that polyclonal rabbit IAPP antisera label beta cells close to amyloid only weakly. Whether this lack of immunoreactivity depends on lack of IAPP or on hidden epitopes is in question. In the present study, we show that the IAPP immunoreactivity of these beta cells is possible to retrieve. On the other hand, the monoclonal IAPP antibody 4A5, which labels IAPP in beta cells, does not label IAPP in its native amyloid form. We show evidence that this lack of immunoreactivity is not dependent on conformational change of the IAPP molecules in the amyloidogenesis but is likely owing to glycation of IAPP in human islet amyloid deposits.
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Affiliation(s)
- Z Ma
- Division of Molecular and Immunological Pathology, Linköping University, Sweden
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Nilsson MR, Raleigh DP. Analysis of amylin cleavage products provides new insights into the amyloidogenic region of human amylin. J Mol Biol 1999; 294:1375-85. [PMID: 10600392 DOI: 10.1006/jmbi.1999.3286] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Human amylin is the primary component of amyloid deposits found in the pancreatic beta-cells of patients with type 2 diabetes mellitus. Recently, two fragments of amylin have been identified in vivo. One fragment contains residues 17 to 37 of human amylin (AMYLIN17-37) and the other contains residues 24 to 37 (AMYLIN24-37). The secondary structure and amyloid forming ability of each peptide was determined at pH 5.5(+/-0.3) and pH 7.4(+/-0.3). Results at these two values of pH were very similar. Both peptides are predominantly unstructured in solution (CD) but adopt a significant amount of beta-sheet secondary structure upon aggregation (FTIR). Transmission electron microscopy (TEM) confirmed the presence of amyloid fibrils. AMYLIN24-37 was further dissected by studying peptides corresponding to residues 24 to 29 and 30 to 37. The AMYLIN30-37 peptide forms amyloid deposits. Samples of the 24 to 29 fragment which had TFA as the associated counterion formed ordered deposits but samples associated with HCl did not. Residues 20 to 29 are traditionally thought to be the amyloidogenic region of amylin, but this study demonstrates that peptides derived from other regions of amylin are capable of forming amyloid, and hence indicates that these regions of amylin can play a role in amyloid formation.
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Affiliation(s)
- M R Nilsson
- Department of Chemistry, State University of New York at Stony Brook, Stony Brook, NY 11794-3400, USA
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Westermark G, Westermark P, Eizirik DL, Hellerström C, Fox N, Steiner DF, Andersson A. Differences in amyloid deposition in islets of transgenic mice expressing human islet amyloid polypeptide versus human islets implanted into nude mice. Metabolism 1999; 48:448-54. [PMID: 10206436 DOI: 10.1016/s0026-0495(99)90102-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Islet amyloid polypeptide (IAPP)-derived amyloid is frequently deposited in the islets of Langerhans in patients with chronic non-insulin-dependent diabetes mellitus (NIDDM). When human islets were implanted under the renal capsule in nude mice, amyloid occurred in 73% of the grafts within 2 weeks. In this study, we compare the deposition of amyloid in islets from a transgenic mouse strain expressing human IAPP (hIAPP) and in normal human islets after implantation in nude mice. The implantations were performed as follows: (1) nondiabetic recipients were given islets from transgenic mice alone, (2) human islets were implanted in the upper pole of the kidney and islets from transgenic mice were implanted in the lower pole of the kidney, (3) grafts containing a mixture of human and transgenic islets were implanted, and (4) transgenic islets and islets from nontransgenic littermates were implanted in therapeutic numbers into recipients made diabetic by a single injection of alloxan prior to implantation. The implants were removed after various periods from 4 days to 8 weeks. The implants were either fixed in Formalin, stained for amyloid, and viewed in polarized light, or processed for immunoelectron microscopy and studied after immunolabeling with specific antibodies against IAPP. We found that the course of amyloid deposition differed significantly between human islets and hIAPP-expressing mouse islets. In human islets, amyloid was mainly deposited intracellularly and only small amounts of amyloid were found extracellularly. In contrast, in islets from transgenic mice, amyloid was exclusively deposited extracellularly and deposition in this site was preceded by an aggregation of immunoreactive material along the basement membrane. These findings point to separate mechanisms for amyloid formation in these two models.
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Affiliation(s)
- G Westermark
- Division of Molecular and Immunological Pathology, Linköping University, Sweden
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Ma Z, Westermark GT, Johnson KH, O'Brien TD, Westermark P. Quantitative immunohistochemical analysis of islet amyloid polypeptide (IAPP) in normal, impaired glucose tolerant, and diabetic cats. Amyloid 1998; 5:255-61. [PMID: 10036583 DOI: 10.3109/13506129809007298] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Islet amyloid polypeptide (IAPP, "amylin") has been proposed as having important roles in the pathogenesis of type 2 diabetes mellitus via its biological activity and by forming islet amyloid. The domestic cat develops a type of diabetes that closely resembles type 2 diabetes in humans, including the frequent formation of islet amyloid deposits in the impaired glucose tolerant (IGT) and diabetic state. With the aid of computerized image analysis and immunohistochemistry, we examined the IAPP and insulin content in pancreatic islets of normal, IGT and diabetic cats. IAPP immunoreactivity in beta cells from IGT cats was significantly stronger (p < 0.01) as compared with cells from normal cats, while the insulin labelling strength was unchanged. Overtly diabetic cats were usually almost devoid of beta cells. As in humans, cellular IAPP but not IAPP in islet amyloid deposits was labelled by the newly developed monoclonal antibody to IAPP 4A5, thus providing further evidence that IAPP is modified by a yet unknown mechanism during the amyloidogenic process. The study provides evidence that an increased beta cell storage of IAPP independent of insulin may be an important factor in the early phase of the development of islet amyloid in this form of diabetes.
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Affiliation(s)
- Z Ma
- Division of Molecular and Immunological Pathology, Faculty of Health Sciences, Linköping University, Sweden
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Mulder H, Ekelund M, Ekblad E, Sundler F. Islet amyloid polypeptide in the gut and pancreas: localization, ontogeny and gut motility effects. Peptides 1997; 18:771-83. [PMID: 9285924 DOI: 10.1016/s0196-9781(97)00008-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The occurrence of islet amyloid polypeptide (IAPP) in the gut and pancreas of several species and during ontogeny of the rat, was studied using immunocytochemistry. Effects of IAPP on rat ileal smooth muscle were assessed in vitro. Islets of most, but not all, species examined, displayed IAPP in insulin cells and, in some species, also in somatostatin- and peptide YY (PYY)-containing cells. In the gut, expression of IAPP varied among species; when present, IAPP was most abundant in the proximal part and co-localized with somatostatin, PYY, gastrin/cholecystokinin, enteroglucagon or serotonin. IAPP was first demonstrated at embryonic day 12 and 16 in islet and gastrointestinal endocrine cells, respectively. IAPP relaxed gut muscle and reduced electrical field stimulation-evoked contractions, presumably by inhibiting acetylcholine release. Thus, IAPP expression in islets is consistent with an important role for IAPP in fuel metabolism; the gastrointestinal expression and motor effects of IAPP suggest that IAPP may modulate gastrointestinal function.
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Affiliation(s)
- H Mulder
- Department of Physiology and Neuroscience, University of Lund, Lund University Hospital, Sweden.
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Oosterwijk C, Höppener JW, van Hulst KL, Lips CJ. Pancreatic islet amyloid formation in patients with noninsulin-dependent diabetes mellitus. Implication for therapeutic strategy. INTERNATIONAL JOURNAL OF PANCREATOLOGY : OFFICIAL JOURNAL OF THE INTERNATIONAL ASSOCIATION OF PANCREATOLOGY 1995; 18:7-14. [PMID: 7594773 DOI: 10.1007/bf02825416] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Islet amyloid polypeptide (IAPP or amylin) is the main component of pancreatic islet amyloid found in the vast majority of patients with noninsulin-dependent (Type-2) diabetes mellitus (NIDDM). IAPP may also act as a hormone that antagonizes the effects of insulin on peripheral tissues, but the results with IAPP overproducing transgenic mice and other recent findings indicate that IAPP overproduction is unlikely to induce peripheral insulin resistance in NIDDM. However, IAPP may contribute to the progression of NIDDM by impairing beta-cell function via islet amyloid formation. This may be initiated by locally elevated IAPP concentrations, induced by insulin-resistance-associated beta-cell hyperactivity. In order to improve therapeutic results, we propose strategies to inhibit IAPP production and islet amyloid formation during the pathogenesis of NIDDM.
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Affiliation(s)
- C Oosterwijk
- Department of Internal Medicine, Utrecht University Hospital, The Netherlands
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Westermark P, Eizirik DL, Pipeleers DG, Hellerström C, Andersson A. Rapid deposition of amyloid in human islets transplanted into nude mice. Diabetologia 1995; 38:543-9. [PMID: 7489836 DOI: 10.1007/bf00400722] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Human islets of Langerhans were transplanted to the subcapsular space of the kidneys of nude mice which were either normoglycaemic or made diabetic with alloxan. After 2 weeks, the transplants were processed for light and electron microscopical analyses. In all transplants, islet amyloid polypeptide (IAPP)-positive cells were found with highest frequency in normoglycaemic animals. IAPP-positive amyloid was seen in 16 out of 22 transplants (73%), either by polarisation microscopy after Congo red staining or by immune electron microscopy. At variance with previous findings of amyloid deposits exclusively in the extracellular space of islets of non-insulin-dependent diabetic patients, the grafted islets contained intracellular amyloid deposits as well. There was no clear difference in occurrence of amyloid between diabetic and non-diabetic animals. The present study indicates that human islets transplanted into nude mice very soon present IAPP-positive amyloid deposits. This technique may provide a valuable model for studies of the pathogenesis of islet amyloid and its impact on islet cell function.
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Affiliation(s)
- P Westermark
- Department of Pathology, Linköping University, Sweden
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Höppener JW, Verbeek JS, de Koning EJ, Oosterwijk C, van Hulst KL, Visser-Vernooy HJ, Hofhuis FM, van Gaalen S, Berends MJ, Hackeng WH. Chronic overproduction of islet amyloid polypeptide/amylin in transgenic mice: lysosomal localization of human islet amyloid polypeptide and lack of marked hyperglycaemia or hyperinsulinaemia. Diabetologia 1993; 36:1258-65. [PMID: 8307253 DOI: 10.1007/bf00400803] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Type 2 (non-insulin-dependent) diabetes mellitus is characterised by hyperglycaemia, peripheral insulin resistance, impaired insulin secretion and pancreatic islet amyloid formation. The major constituent of islet amyloid is islet amyloid polypeptide (amylin). Islet amyloid polypeptide is synthesized by islet beta cells and co-secreted with insulin. The ability of islet amyloid polypeptide to form amyloid fibrils is related to its species-specific amino acid sequence. Islet amyloid associated with diabetes is only found in man, monkeys, cats and racoons. Pharmacological doses of islet amyloid polypeptide have been shown to inhibit insulin secretion as well as insulin action on peripheral tissues (insulin resistance). To examine the role of islet amyloid polypeptide in the pathogenesis of Type 2 diabetes, we have generated transgenic mice with the gene encoding either human islet amyloid polypeptide (which can form amyloid) or rat islet amyloid polypeptide, under control of an insulin promoter. Transgenic islet amyloid polypeptide mRNA was detected in the pancreas in all transgenic mice. Plasma islet amyloid polypeptide levels were significantly elevated (up to 15-fold) in three out of five transgenic lines, but elevated glucose levels, hyperinsulinaemia and obesity were not observed. This suggests that insulin resistance is not induced by chronic hypersecretion of islet amyloid polypeptide. Islet amyloid polypeptide immunoreactivity was localized to beta-cell secretory granules in all mice. Islet amyloid polypeptide immunoreactivity in beta-cell lysosomes was seen only in mice with the human islet amyloid polypeptide gene, as in human beta cells, and might represent an initial step in intracellular formation of amyloid fibrils.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J W Höppener
- Laboratory for Physiological Chemistry, Utrecht University, The Netherlands
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