Evidence that upregulation of serum IGF-1 concentration can trigger acceleration of diabetic retinopathy

BACKGROUND Acute reduction of chronic hyperglycaemia can accelerate early diabetic retinopathy. In adolescent patients with Mauriac’s syndrome, this phenomenon is related to an upregulation of subnormal serum IGF-1 levels. AIM To obtain longitudinal data on serum IGF-1 and retinopathy status in poorly controlled adult insulin dependent (type 1) diabetic patients without Mauriac’s syndrome, in whom hyperglycaemia is reduced by intensive insulin therapy. METHODS Four patients with chronic severe insulin deficiency and early microangiopathy were studied prospectively. Changes in plasma glucose, HbA1c, serum IGF-1 levels, proteinuria, retinopathy, and clinical status were followed up closely. RESULTS Reducing hyperglycaemia from >16 mmol/l (equivalent to HbA1c>11%) to