Endocrine Abstracts

Background: Congenital hyperinsulinism (CHI) is the commonest cause of persistent hypoglycaemia and is due to the unregulated secretion of insulin from the pancreatic beta-cells. The role of gut hormones and dipeptidyl peptidase-4 (DPP-4) is currently unknown in patients with CHI.

Aims: To evaluate the expression pattern of DPP-4 in focal and diffuse CHI.

Method: Using intra-operative formalin-fixed paraffin embedded (FFPE) pancreatic sections; the localisation of DPP-4 in alpha-, beta- and delta-cells was carried out in patients with either diffuse CHI (DCHI) or focal CHI (FCHI) with tissue sections taken from around the focal lesion being used as controls. Additionally, using the proliferative marker, Ki67, we attempted to identify the islet-cells that were proliferating.

Results: We identified expression of DPP-4 with insulin, glucagon and somatostatin in their respective cell subtypes. Both DCHI and FCHI sections showed an increase in Ki67 expression. In comparison to control tissue, DCHI showed an increase in beta-cell DPP-4 expression. However, this was absent in the focal lesions.

Conclusion: In conclusion, this is the first study to show that DPP-4 expression profiles are histologically different in DCHI and FCHI patients. Therefore, DPP-4 might have a role in the pathophysiology of DCHI and this knowledge might be useful for potential therapeutic applications.