doi:10.1369/jhc.6A7024.2006
Volume 55 (2): 111-118, 2007 Copyright ©The Histochemical Society, Inc. Distribution of Pancreatic Endocrine Cells Including IAPP-expressing Cells in Non-diabetic and Type 2 Diabetic Cases
UNMC Eppley Cancer Center (KI,PMP) and Department of Pathology and Microbiology (PMP), University of Nebraska Medical Center, Omaha, Nebraska Correspondence to: Parviz M. Pour, MD, 986805 Nebraska Medical Center, Omaha, NE 68198-6805. E-mail: ppour{at}unmc.edu
There is a lack of agreement on the distribution of islet amyloid polypeptide (IAPP) in the pancreases of healthy and diabetic subjects. Therefore, a detailed morphometrical and immunohistochemical study was performed to obtain information on the distribution of cells expressing insulin, glucagon, somatostatin, pancreatic polypeptide (PP), and IAPP in the pancreases of non-diabetic (n=4) and diabetic individuals (n=6). In the non-diabetic cases, ß-cells contributed to 64%, -cells to 26%, -cells to 8%, PP cells to 0.3%, and IAPP cells to 34% of the islet cell population. The ratio of IAPP/insulin was 1:2. In diabetic cases, ß-cells were decreased by 24%, and IAPP was decreased by 57%. The - and -cells were increased by 40% and 58%, respectively. IAPP/insulin ratio was decreased by 41%. Thus, only 50% of the ß-cells in non-diabetics and only 30% in diabetics coexpressed IAPP. In diabetics, more -cells coexpressed IAPP than in non-diabetics. The results seem to argue against the notion that the secretion of IAPP is increased in diabetics. It is possible that an increase in somatostatin and glucagon plays a greater role in diabetes than IAPP. (J Histochem Cytochem 55:111118, 2007)
Key Words: diabetes islets islet amyloid polypeptide morphometry immunohistochemistry
TYPE 2 DIABETES is characterized by a deficit in ß-cells, increased ß-cell apoptosis, impaired insulin secretion, and an alteration in islet amyloid polypeptide (IAPP) secretion (Butler et al. 2003
Tissues Eleven pancreases from donors, all due to accidental deaths, were examined (Table 1 ). Six of the donors had type 2 diabetes (DM); only one required insulin (case 6). The remaining cases (two males and three females) had no history of pancreatic disease. Average age of donors was 44.8 years (range 1870 years). Two of the type 2 diabetic patients were female and four were male, with an average age of 55 years (range 2784 years). We do not know which region of the pancreas the samples came from. Based on immunohistochemical (IHC) results, however, all tissues were from the glucagon-rich region. All tissues were fixed in formalin and processed for histology by conventional methods. One section of each sample was stained with hematoxylin and eosin (H&E) and evaluated histopathologically for suitability for the study using the following criteria: (1) intact tissue with no evidence of autolysis, (2) sample diameter of at least 1.0 x 1.0cm, and (3) an adequate number of islets (at least five islets per section). Selected tissues were cut in 30 serial sections.
IHC Immunostaining was carried out using an avidinbiotinperoxidase complex (ABC) method with mouse monoclonal anti-IAPP antibody (clone R10/99; Lab Vision, Fremont, CA); rabbit polyclonal IAPP antibody (Abcam; Cambridge, MA); mouse monoclonal anti-insulin antibody; and polyclonal antibodies against glucagon, somatostatin, and pancreatic polypeptide (PP) (Zymed Laboratories; South San Francisco, CA). For IAPP, IHC staining antigen retrieval was performed by incubating the sections with 0.1 N citrate buffer (pH 6.2) at 100C for 10 min. For polyclonal antibody, protinase K was also used. Several methods were used for visualization of islet hormones. Consecutive serial sections were processed with individual antibodies, and microphotographs were taken from each section. Sections stained with IAPP and another antibody (insulin, glucagon, somatostatin, or PP) were superimposed in Adobe Photoshop (Adobe Systems; Mountain View, CA), and the stained cells in each layer of Photoshop were counted. Only nucleated stained cells were counted. This technique allowed us to identify cells that coexpressed both hormones (Figure 1 ). In addition, slides were also processed by a multi-labeling method (Pour et al. 1994
Determination of Islet Size In the H&E-stained slides, diameters of 200 randomly selected islets/pancreas were measured by a microscale using a Zeiss Axiomat microscope (Carl Zeiss; Oberkochen, Germany). The average value was considered to be the size of the islets (area: µm2 = x length a/2 x length b/2).
Statistical Evaluation
Normal Pancreas The number of islets per specimen and the size and percentage of the endocrine cells are summarized in Table 1. Islet size varied between 50 and 250 µm and was smaller in the younger case (case 1) than in the others (Table 1). The number of individual islet cells varied among the cases and even within the same tissue. The number of islet cells did not differ significantly among cases and was independent of the size of the islets. In each case and in every islet, the number of IAPP cells was about one-half the number of ß-cells, except in case 1, which had the highest number of IAPP cells. The difference, however, was not significant. Although expression of IAPP coincided with the ß-cells in each case, a few cells in the islet periphery were expressed in cells unstained with anti-insulin (Figure 1). Results of the monoclonal and polyclonal antibodies did not differ except for the quality of the staining, which was stronger with the monoclonal antibody. This was also the case in the pancreases from the diabetic cases.
Pancreases in Type 2 Diabetic Cases
Some islets appeared unusually large because of amyloid deposition and edema, measuring between 200 and 350 µm. Amyloid deposits were strongly stained with Congo red but showed no reactivity or only a weak reactivity to anti-IAPP. Excluding these large islets, the size of intact islets was significantly smaller in all six cases. The numbers of IAPP and ß-cells were lower and the numbers of Remarkably, there was a marked proliferation of centroacinar cells in many areas close to or remote from the distorted islets in all six cases (Figure 2D ). These cells, generally located within the acini, had a large semi-transparent cytoplasm (Figure 2) and reacted with both IAPP antibodies (Figure 3 ). Between these cells there were a few or single cells immunoreactive with insulin, glucagon, somatostatin, or PP antibodies (Figure 3B).
No differences were found in the number of PP cells among the cases and between the pancreases of normal cases and diabetic cases.
IAPP has been shown to inhibit the secretion of a variety of hormones including insulin (Stridsberg and Wilander 1991
In the present study, some undisclosed patterns of pancreatic endocrine cells in non-diabetics and type 2 diabetics were noted. Although it is generally believed that IAPP is coproduced, costored, and cosecreted with insulin, in our series only
If diabetes is caused by an increase of IAPP secretion from ß-cells as reported, a larger number of IAPP-expressing cells was expected to be found in diabetic cases. The opposite, however, was noted. The number of cells immunoreactive with anti-insulin and anti-IAPP was significantly lower in diabetic than in non-diabetic cases. Also, a lower number of ß-cells coexpressed IAPP. Reduction of ß-cells by
We did not have any information on the therapeutic scheme of the type 2 diabetic cases. Based on the severity of the islet alteration in case 11, we assumed that the patient was treated with insulin. If so, then there was no difference in the pattern of IAPP between this and the other cases. Contrary to the experimental study (Lindstrom et al. 1997
Nevertheless, the morphometrical finding seems to argue against the notion that more IAPP is produced and released in diabetes. In fact, if one of the many functions of IAPP is to suppress the secretion of insulin possibly by a paracrine route (Tokuyama et al. 1997
In agreement with previous studies (Madsen et al. 1991
The increase of glucagon and somatostatin cells in diabetic cases was much greater than reported elsewhere (Clark et al. 1995
Marked hyperplasia of centroacinar cells found only in diabetic cases was noteworthy. The strong reactivity of these cells with the anti-IAPP that we used has not been reported with any other monoclonal anti-IAAP antibodies (Ma et al. 1997
The present study warrants further morphometrical and clinical studies in diabetic subjects to better understand the role of IAPP in this disease. In such studies, attention should be paid to the expression of IAPP in extrapancreatic tissues because the coexpression of IAPP has been found in the intestinal endocrine cells of animals (Mulder et al. 1994
This study was supported by grants from the National Cancer Institute's Laboratory Cancer Research Center (Support Grant CA-367127) and the American Cancer Society Special Institutional Grant.
Received for publication May 30, 2006; accepted August 31, 2006
Ahren B, Gutniak M (1997) No correlation between insulin and islet amyloid polypeptide after stimulation with glucagon-like peptide-1 in type 2 diabetes. Eur J Endocrinol 137:643649[Abstract] Bonner-Weir S (2001) ß-cell turnover. Its assessment and implications. Diabetes 50(suppl 1):S2024[Medline] Butler AE, Jang J, Gurlo T, Carty MD, Soeller WC, Butler PC (2004) Diabetes due to a progressive defect in ß-cell mass in rats transgenic for human islet amyloid polypeptide (HIP Rat): a new model for type 2 diabetes. Diabetes 53:15091516 Butler AE, Janson J, Soeller WC, Butler PC (2003) Increased ß-cell apoptosis prevents adaptive increase in ß-cell mass in mouse model of type 2 diabetes: evidence for role of islet amyloid formation rather than direct action of amyloid. Diabetes 52:23042314 Clark A, de Koning EJ, Hattersley AT, Hansen BC, Yajnik CS, Poulton J (1995) Pancreatic pathology in non-insulin dependent diabetes (NIDDM). Diabetes Res Clin Pract 28(suppl):S3947 Corbett J, Serup P, Bonner-Weir S, Nielsen JH (1997) Beta-cell ontogeny: growth and death. Diabetologia 40(suppl 3):B2732 De Vroede M, Foriers A, Van de Winkel M, Madsen O, Pipeleers D (1992) Presence of islet amyloid polypeptide in rat islet B and D cells determines parallelism and dissociation between rat pancreatic islet amyloid polypeptide and insulin content. Biochem Biophys Res Commun 182:886893[CrossRef][Medline] Enoki S, Mitsukawa T, Takemura J, Nakazato M, Aburaya J, Toshimori H, Matsukara S (1992) Plasma islet amyloid polypeptide levels in obesity, impaired glucose tolerance and non-insulin-dependent diabetes mellitus. Diabetes Res Clin Pract 15:97102[CrossRef][Medline] Gerich JE (1981) Somatostatin and diabetes. Am J Med 70:619626[CrossRef][Medline] Hanabusa T, Kubo K, Oki C, Nakano Y, Okai K, Sanke T, Nanjo K (1992) Islet amyloid polypeptide (IAPP) secretion from islet cells and its plasma concentration in patients with non-insulin-dependent diabetes mellitus. Diabetes Res Clin Pract 15:8996[CrossRef][Medline] Janson J, Soeller WC, Roche PC, Nelson RT, Torchia AJ, Kreutter DK, Butler PC (1996) Spontaneous diabetes mellitus in transgenic mice expressing human islet amyloid polypeptide. Proc Natl Acad Sci USA 93:72837288 Johnson KH, O'Brien TD, Jordan K, Westermark P (1989) Impaired glucose tolerance is associated with increased islet amyloid polypeptide (IAPP) immunoreactivity in pancreatic beta cells. Am J Pathol 135:245250[Abstract] Lindstrom T, Leckstrom A, Westermark P, Arnqvist HJ (1997) Effect of insulin treatment on circulating islet amyloid polypeptide in patients with NIDDM. Diabet Med 14:472476[CrossRef][Medline] Ma Z, Westermark GT, Li ZC, Engstrom U, Westermark P (1997) Altered immunoreactivity of islet amyloid polypeptide (IAPP) may reflect major modifications of the IAPP molecule in amyloidogenesis. Diabetologia 40:793801[CrossRef][Medline] Ma Z, Westermark P, Westermark GT (2000) Amyloid in human islets of Langerhans: immunologic evidence that islet amyloid polypeptide is modified in amyloidogenesis. Pancreas 21:212218[CrossRef][Medline] Madsen OD, Nielsen JH, Michelsen B, Westermark P, Betsholtz C, Nishi M, Steiner DF (1991) Islet amyloid polypeptide and insulin expression are controlled differently in primary and transformed islet cells. Mol Endocrinol 5:143148[CrossRef][Medline] Marzban L, Park K, Verchere CB (2003) Islet amyloid polypeptide and type 2 diabetes. Exp Gerontol 38:347351[CrossRef][Medline] Mulder H, Ahren B, Stridsberg M, Sundler F (1995a) Non-parallelism of islet amyloid polypeptide (amylin) and insulin gene expression in rats islets following dexamethasone treatment. Diabetologia 38:395402[Medline] Mulder H, Ahren B, Sundler F (1995b) Differential expression of islet amyloid polypeptide (amylin) and insulin in experimental diabetes in rodents. Mol Cell Endocrinol 114:101109[CrossRef][Medline] Mulder H, Ahren B, Sundler F (1996) Islet amyloid polypeptide (amylin) and insulin are differentially expressed in chronic diabetes induced by streptozotocin in rats. Diabetologia 39:649657[Medline] Mulder H, Gebre-Medhin S, Betsholtz C, Sundler F, Ahren B (2000a) Islet amyloid polypeptide (amylin)-deficient mice develop a more severe form of alloxan-induced diabetes. Am J Physiol Endocrinol Metab 278:E684691 Mulder H, Lindh AC, Ekblad E, Westermark P, Sundler F (1994) Islet amyloid polypeptide is expressed in endocrine cells of the gastric mucosa in the rat and mouse. Gastroenterology 107:712719[Medline] Mulder H, Martensson H, Sundler F, Ahren B (2000b) Differential changes in islet amyloid polypeptide (amylin) and insulin mRNA expression after high-fat diet-induced insulin resistance in C57BL/6J mice. Metabolism 49:15181522[CrossRef][Medline] Orci L, Baetens D, Rufener C, Amherdt M, Ravazzola M, Studer P, Malaisse-Lagae F, et al. (1976) Hypertrophy and hyperplasia of somatostatin-containing D-cells in diabetes. Proc Natl Acad Sci USA 73:13381342 Pour PM (2006) Centroacinar cellsa neglected essential element of the pancreas. In Pour PM, ed. Toxicology of the Pancreas. Boca Raton, FL, Taylor & Francis Pour PM, Kazakoff K, Dulany K (1994) A new technique for simultaneous demonstration of 4 tumor-associated antigens in pancreatic cancer cells. Zentralbl Pathol 140:397401[Medline] Rocken C, Linke RP, Saeger W (1992) Immunohistology of islet amyloid polypeptide in diabetes mellitus: semi-quantitative studies in a post-mortem series. Virchows Arch A Pathol Anat Histopathol 421:339344[CrossRef][Medline] Stefan Y, Orci L, Malaisse-Lagae F, Perrelet A, Patel Y, Unger RH (1982) Quantitation of endocrine cell content in the pancreas of nondiabetic and diabetic humans. Diabetes 31:694700[Abstract] Stridsberg M, Sandler S, Wilander E (1993) Cosecretion of islet amyloid polypeptide (IAPP) and insulin from isolated rat pancreatic islets following stimulation or inhibition of beta-cell function. Regul Pept 45:363370[CrossRef][Medline] Stridsberg M, Wilander E (1991) Islet amyloid polypeptide (IAPP). A short review. Acta Oncol 30:451456[Medline] Takada K, Kanatsuka A, Tokuyama Y, Yagui K, Nishimura M, Saito Y, Makino H (1996) Islet amyloid polypeptide/amylin contents in pancreas change with increasing age in genetically obese and diabetic mice. Diabetes Res Clin Pract 33:153158[CrossRef][Medline] Tokuyama T, Yagui K, Yamaguchi T, Huang CI, Kuramoto N, Shimada F, Miyazaki J, et al. (1997) Expression of human islet amyloid polypeptide/amylin impairs insulin secretion in mouse pancreatic beta cells. Metabolism 46:10441051[CrossRef][Medline] Yoon KH, Ko SH, Cho JH, Lee JM, Ahn YB, Song KH, Yoo SJ, et al. (2003) Selective ß-cell loss and
|
|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||