Searchable abstracts of presentations at key conferences in endocrinology
Endocrine Abstracts (2012) 29 P571

ICEECE2012 Poster Presentations Diabetes (248 abstracts)

Innervation and vascularization into islets of langerhans in the presence or absence of proglucagon-derived peptides

Y Hayashi 1 , H Tanaka 1 , N Sanzen 2 , K Sekiguchi 2 & Y Murata 1

1Nagoya University, Nagoya, Japan; 2Osaka University, Osaka, Japan.

Introduction: Islets of Langerhans are well innervated and vascularized, however, the regulatory mechanisms for innervation and vascularization are not well clarified. In mice deficient for proglucagon-derived peptides (Gcg–gfp/gfp: GCGKO), islet cells that express green fluorescent protein (GFP) under the control of glucagon promoter (‘α”-cells) display hyperplasia and number of islets is increased. The present study was aimed to clarify role of the proglucagon-derived peptides in innervation and vascularization into islets.

Method: Immunohistochemical analyses for pancreata of GCGKO and heterozygous Gcg–gfp/+mice were performed by using antibodies for platelet-endothelial cell adhesion molecule-1 (PECAM1), vascular endothelial growth factor (VEGF), tyrosin hydroxylase (TH), laminin, synapsin I, neuropeptide Y (NPY) and insulin.

Results: Neuronal fibers positive for NPY and/or TH were identified in and around islets of both Gcg-gfp/+ and GCGKO mice. Basement membranes positive for laminin were present around the islets and blood vessels. Synapsin positive spots were mostly identified nearby blood vessels and α-cells. Some of the non-α-cells were positive for TH. NPY was detected in some of α-cells, β-cells and cells negative for both glucagon and insulin. VEGF were expressed in both α-cells and β-cells. In GCGKO islets that contained mostly GFP positive ‘α’-cells and β-cells, numbers of blood vessels and nerves, as well as signal intensities of VEGF, NPY, and TH were reduced.

Conclusion: Proglucagon-derived peptides are not an absolute prerequisite for innervation and vascularization into islets. However, reduced innervation and vascularization into malformed GCGKO islets consisted of mostly GFP positive ‘α’-cells suggested that non-α populations play regulatory role in establishing networks of nerves and blood vessels in islets of Langerhans.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This work was supported, however funding details unavailable.

Figure 1. Islets of Langerhans in glucagon–GFP knock-in mice. Green: GFP autofluorescence, Red: Insulin.


Volume 29

15th International & 14th European Congress of Endocrinology

European Society of Endocrinology 

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