|
|
||||||||
ARTICLE |
University of Cambridge, Department of Paediatrics, Box 116, Addenbrookes Hospital, Hills Road, Cambridge, CB2 2QQ, UK and 1 Department of Clinical Biochemistry, Box 232, Addenbrooks Hospital, Hills Road, Cambridge, CB2 2QQ, UK
(Correspondence should be addressed to D B Dunger; Email: dbd25{at}cam.ac.uk)
This paper was presented at the Ipsen symposium, The evolving biology of growth and metabolism, Lisbon, Portugal, 16–18 March 2007. Ipsen has supported the publication of these proceedings.
Abstract
Severe insulin resistance resulting from known or putative genetic defects affecting the insulin receptor or post-insulin receptor signalling represents a clinical spectrum ranging from Donohues and Rabson–Mendenhall syndrome, where the genetic defect is identified, through to the milder phenotype of type A insulin resistance, where a genetic defect can only be detected in around 10% of cases. Paradoxically, subjects with these conditions may present with hypoglycaemia due to mismatch of post-prandial glucose excursion and compensatory hyperinsulinaemia. Ultimately, treatment with insulin and insulin sensitisers will be unsuccessful and subjects may succumb to diabetes or its complications. Recombinant human IGF-I alone or combined with its binding protein (IGFBP-3) provides an alternative therapy as IGF-I receptor shares structural and functional homology with the insulin receptor and recombinant human insulin-like growth factor I (rhIGF-I) therapy could improve glucose disposal by signalling through the IGF-I receptor, whilst reducing the adverse effects of high insulin concentrations. There are also data which indicate that IGF-I signalling through the IGF-I receptor on the pancreatic ß-cell may be important in maintaining insulin secretion. Pilot studies confirmed that rhIGF-I could reduce glucose and insulin levels in subjects with type A insulin resistance and those with Rabson–Mendenhall syndrome with sustained beneficial effects on HbA1c. Continued study has confirmed efficacy of rhIGF-I when combined with IGFBP-3 in the treatment of Donohues and type A insulin resistance subjects. Observations that IGF-I treatment can improve C-peptide levels in these subjects may indicate that it might be more valuable as a first line intervention to preserve ß-cell function, rather than its current use as a medication of last resort in subjects where all other therapies have failed.
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |