Background: Congenital hyperinsulinism in infancy (CHI) is a neonatal disorder of uncontrolled insulin release leading to profound hypoglycaemia. In addition to defects in pancreatic β-cell function, we have recently demonstrated that the CHI pancreas is highly proliferative, with rates of proliferation up to 14-fold higher than in age-matched controls.
Objective and hypotheses: As patients require pancreatectomy to alleviate hypoglycaemia, our aim was to demonstrate that CHI pancreatic tissue could represent a novel source of pancreatic stem cells.
Method: Proliferating cell lines were derived from the pancreata of three patients with CHI following surgery and from the islet-enriched digest of an adult donor. In two cases CHI was caused by ABCC8 gene defects in association with focal- and diffuse disease. In the third case atypical CHI, no mutations in CHI-associated loci have been found. RT-PCR was used to examine gene expression profiles; western blot, flow cytometry, and immunocytochemistry for protein analysis.
Results: All three cell lines were found to express Islet1, MafB, Pax6, and Sox9, markers associated with pancreatic development, and low level insulin. Profiling by flow cytometry for mesenchymal stem cell (MSC) markers demonstrated cells to be positive for CD105, CD44 and CD90, and negative for CD45, as in published literature. The morphology of CHI-derived pancreatic MSCs (pMSC) lines was consistent and they were readily able to form islet-like clusters in low adherence culture. Differentiation to adipocyte-, chondrocyte-, and osteocyte lineages was achieved for all three lines indicating multipotency. CHI-derived pMSCs proliferated faster than adult pMSCs (doubling time of 90 h vs 195 h) and continued to proliferate beyond their adult counterparts.
Summary: pMSCs have not been previously derived from CHI patients. We have shown this is feasible, reproducible and that this tissue source has advantages over adult pMSCs, including insulin gene expression and longer-term stability, viability, and differentiation capacity.
Funding: The National Institute of Health Research.
01 - 03 Oct 2015
European Society for Paediatric Endocrinology