An Improved Method for the Determination of Islet Amyloid Polypeptide Levels in Plasma

Hulst, Karen L. van; Hackeng, W. H. L.; Höppener, Jo W.M.; Jaarsveld, Brigit C. van; Nieuwenhuis, M. G.; Blankenstein, M.A.; Lips, C. J. M.

doi:10.1177/000456329403100209

Cited by 18 publications

(16 citation statements)

References 35 publications

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“…Blood was collected in EDTA-tubes, which were kept on ice until centrifugation at 1500 g for 5 min at 4 C. Plasma was taken, divided in aliquots and stored at ±80 C until analysis. Immunoreactive IAPP was measured in 50±100 ml plasma by radioimmunoassay (RIA) as described [12,14], using hIAPP antiserum K1338 that shows full cross-reactivity with synthetic rat IAPP(1±37), which is identical to mouse IAPP(1±37). Thus, the sum of endogenous mouse IAPP plus transgenic hIAPP was determined.…”

Section: Methodsmentioning

confidence: 99%

Extensive islet amyloid formation is induced by development of Type II diabetes mellitus and contributes to its progression: pathogenesis of diabetes in a mouse model

et al. 1999

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Type II (non-insulin-dependent) diabetes mellitus is a common, age-related, multifactorial disease [1,2]. Although still debated, it seems that the primary defect in most subjects developing Type II diabetes involves resistance to insulin action in muscle or liver or in both which initially is compensated for by increased insulin secretion. When in addition insulin production becomes impaired (ªbeta-cell exhaustionº), however, glucose intolerance or overt diabetes may develop [3±5]. Therefore, factors inhibiting insulin production might promote progression to overt diabetes in subjects with insulin resistance. Islet amy- Diabetologia (1999) Abstract Aims/hypothesis. Type II (non-insulin-dependent) diabetes mellitus is a multifactorial disease in which pancreatic islet amyloid is a characteristic histopathological finding. Islet amyloid fibrils consist of the beta-cell protein ªislet amyloid polypeptideº (IAPP)/ªamylinº. Unlike human IAPP (hIAPP), mouse IAPP cannot form amyloid. In previously generated transgenic mice, high expression of hIAPP as such did not induce islet amyloid formation. To further explore the potential diabetogenic role of amyloidogenic IAPP, we introduced a diabetogenic trait (ªobº mutation) in hIAPP transgenic mice. Methods. Plasma concentrations of IAPP, insulin and glucose were determined at 3.5 (t1), 6 (t2), and 16±19 months of age (t3). At t3, the mice were killed and the pancreas was analysed (immuno)histochemically.Results. In non-transgenic ob/ob mice, insulin resistance caused a compensatory increase in insulin production, normalizing the initial hyperglycaemia. In transgenic ob/ob mice, concurrent increase in hIAPP production resulted in extensive islet amyloid formation (more often and more extensive than in transgenic non-ob/ob mice), insulin insufficiency and persistent hyperglycaemia: At t3, plasma insulin levels in transgenic ob/ob mice with amyloid were fourfold lower than in non-transgenic ob/ob mice (p < 0.05), and plasma glucose concentrations in transgenic ob/ ob mice were almost twofold higher (p < 0.05). In addition, the degree of islet amyloid formation in ob/ob mice was positively correlated to the glucose:insulin ratio (r s = 0.53, p < 0.05). Conclusion/interpretation. Islet amyloid is a secondary diabetogenic factor which can be both a consequence of insulin resistance and a cause of insulin insufficiency. [Diabetologia (1999)

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Section: Methodsmentioning

confidence: 99%

Extensive islet amyloid formation is induced by development of Type II diabetes mellitus and contributes to its progression: pathogenesis of diabetes in a mouse model

et al. 1999

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“…The DNA content in tissue pellets was measured (19) as a reference for peptide quantification in the tissue extracts. For the determination of IAPP levels in the circulation, EDTA-plasma of insulinoma patients was extracted with acid-acetone (11).…”

Section: Tissue and Plasma Extractionmentioning

confidence: 99%

“…Immunoreactive IAPP and insulin were measured by RIA as described (11). For the IAPP RIA, IAPP antiserum K1338 to human IAPP was used (22).…”

Section: Radioimmunoassaysmentioning

confidence: 99%

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Islet amyloid polypeptide/amylin messenger RNA and protein expression in human insulinomas in relation to amyloid formation

Hulst¹,

Oosterwijk²,

Born

et al. 1999

European Journal of Endocrinology

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Objective: Islet amyloid polypeptide (IAPP), also named amylin, is the predominant protein component of amyloid deposits in human islet b cell tumours of the pancreas (insulinomas). IAPP is co-produced with insulin by islet b cells. We investigated IAPP expression in relation to insulin expression and to amyloid formation in eleven insulinomas. Design and methods: RNA and protein extracts were prepared from the same pieces of tumour tissue, and from specimens of two normal human pancreata. IAPP and insulin mRNA and peptide content were quantified using Northern blot analysis and radioimmunoassay (RIA) respectively. Molecular forms of IAPP immunoreactivity were analysed by reversed-phase high-performance liquid chromatography (HPLC). The presence of islet hormones and of amyloid was assessed by (immuno)histochemical staining of paraffin sections. Plasma levels of IAPP and insulin prior to tumour resection were determined by RIA. Results: IAPP and insulin mRNA and peptide content varied widely between the tumour specimens, and there was considerable intratumour heterogeneity of peptide content. HPLC analysis indicated correct proteolytic processing of the IAPP precursor protein. Amyloid deposits were detected only in the three tumours with the highest IAPP content. In contrast to insulin, plasma levels of IAPP were not elevated in the insulinoma patients. Conclusions: The spectrum of hormone production by insulinomas cannot be inferred from only a few tissue sections due to intratumour heterogeneity. Expression of the IAPP and insulin genes is not coupled in insulinomas, which produce properly processed mature IAPP. In addition to IAPP overproduction, additional factors such as intracellular accumulation of IAPP are involved in amyloidogenesis in insulinomas.

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“…Plasma levels of insulin were measured by RIA as described (Van Hulst et al, 1994a), using rat insulin standard (Novo Nordisk, Bagsvaerd, Denmark). Plasma levels of IAPP were measured by RIA as described (Van Hulst et al, 1994a), using human IAPP anti-serum K1338 (Van Hulst et al, 1994b) that shows full cross-reactivity with synthetic amidated rat IAPP (Peninsula, Belmont, CA). Serially diluted hamster plasma samples induced a displacement parallel to the standard curve both of rat insulin and of rat IAPP.…”

Section: Assays For the Determination Of Glucose Insulin And Iapp Inmentioning

confidence: 99%

Pancreatic cancer in rats and hamsters does not induce IAPP-related hyperglycaemia

Oosterwijk¹,

Hulst²,

Visser

et al. 1997

Int. J. Cancer

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Many patients with exocrine pancreatic cancer develop diabetes mellitus due to insulin resistance. This may relate to concurrent over-production of islet amyloid polypeptide (IAPP) by the pancreatic beta cells. We investigated the effects of pancreatic cancer on circulating IAPP and glucose homeostasis in azaserine-treated rats (developing acinar pancreatic tumours) and BOP-treated hamsters (developing ductular pancreatic tumours). Glucose, insulin and IAPP levels in plasma were neither affected in azaserine-only treated rats nor in animals with enhanced carcinogenesis after chronic caerulein treatment. Azaserine-treated rats on a high-fat diet had decreased insulin levels and enhanced IAPP/insulin ratios in plasma, without hyperglycaemia. All BOP-treated hamsters showed pancreatic carcinogenesis at 6 months post-treatment. Supranormal plasma glucose levels in animals on a low-fat diet were the only change observed. After a second 6-month period, subnormal plasma glucose levels, at least 4-fold decreased plasma insulin and up to 2-fold decreased plasma IAPP levels were present in all hamsters. Remarkably, both in azaserine-treated rats on high-fat and in BOP-treated hamsters, decreased insulin levels and elevated IAPP/insulin ratios are not associated with hyperglycaemia. In contrast to humans with pancreatic cancer, IAPP overproduction and hyperglycaemia do not develop in rats and hamsters with (pre-)neoplastic pancreatic lesions. Int. J. Cancer 72:637-641, 1997.r 1997 Wiley-Liss, Inc.Human exocrine pancreatic cancer (EPC) usually shows ductular histology and is associated with peripheral insulin resistance and hyperglycaemia in the majority of the patients Gullo et al., 1994;Noy and Bilezikian, 1994). IAPP is a beta-cell polypeptide implicated in the pathogenesis of type-2 diabetes mellitus via the induction of insulin resistance and/or the formation of pancreatic islet amyloid (Cooper, 1994; Höppener et al., 1994;Oosterwijk et al., 1995). In the majority of patients with EPC, over-production both of insulin and of IAPP and elevated IAPP/insulin ratios in plasma were found . Tumour-derived IAPP probably does not significantly contribute to plasma IAPP levels. Although IAPP (and insulin) immunoreactivity was demonstrated in EPC samples, only minor amounts of IAPP could be extracted. Markedly decreased IAPP immunoreactivity in beta cells of tumour-surrounding islets suggested that most intracellular IAPP has been secreted, possibly due to paracrine stimulation by the tumour. It was concluded that IAPP over-production could have induced peripheral insulin resistance in patients with EPC (Pour et al., 1993;Permert et al., 1994). Tumour-induced beta-cell destruction is probably not involved in diabetes, since both the diabetes and elevated IAPP/insulin ratios in plasma disappeared after resection of the tumour Permert et al., 1994). In rats and mice, IAPP administration has been reported to induce insulin resistance and to increase plasma glucose levels (Cooper, 1994). In this respect it is suggestive that also (u...

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An Improved Method for the Determination of Islet Amyloid Polypeptide Levels in Plasma

Cited by 18 publications

References 35 publications

Extensive islet amyloid formation is induced by development of Type II diabetes mellitus and contributes to its progression: pathogenesis of diabetes in a mouse model

Extensive islet amyloid formation is induced by development of Type II diabetes mellitus and contributes to its progression: pathogenesis of diabetes in a mouse model

Islet amyloid polypeptide/amylin messenger RNA and protein expression in human insulinomas in relation to amyloid formation

Pancreatic cancer in rats and hamsters does not induce IAPP-related hyperglycaemia

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