Concern over growth-promoting activity of insulin glargine turned out to be ill-founded when the circulating moiety after injection was noted to have a lower IGF-1:insulin activity than human insulin, and a direct study of retinopathy progression or meta-analysis of malignancy incidence failed to show signals of concern.
Using RNA interference for targeted inhibition of VEGF isoforms in conjunction with IGF-I may be preferable for suppression of HREC overgrowth in vasoproliferative retinopathies such as ROP.
To evaluate longitudinal serum insulin-like growth factor-I (IGF-I) in a large cohort of children and adolescents with type 1 diabetes in relation to hemoglobin A1c (HbA1c), age, diabetes duration, and body mass index (BMI), its association to height and retinopathy, and in comparison with healthy subject references.
Importantly, PWG pups show low serum levels of nonfasting glucose, insulin, and insulin-like growth factor-1 as well as high levels of ghrelin in the early postoxygen-induced retinopathy phase, a combination indicative of poor metabolic supply.
In retinas with and without oxygen-induced retinopathy, the authors assessed with real-time RT-PCR mRNA expression of the IGF-1 receptor (IGF-1R), insulin receptor (IR), IGF-1, IGF-2, insulin (Ins2), and IGF-binding protein 1 (IGFBP1) to IGFBP6 in total retina from postnatal day (P) 7 to P33 to examine changes over time with the induction of retinopathy and at P17 on laser-captured retinal components to quantitatively localize mRNA expression in the ganglion cell layer, the outer nuclear layer, the inner nuclear layer, normal blood vessels, and neovascular tufts.
These results demonstrate the feasibility of IGF-IR ribozyme expression in a selective manner for safer treatment of abnormal angiogenesis associated with retinopathy.
To precisely define the role of insulin and IGF-1 signaling in endothelium in these processes, we have used the oxygen-induced retinopathy model to study mice with a vascular endothelial cell-specific knockout of the insulin receptor (VENIRKO) or IGF-1 receptor (VENIFARKO).