ABSTRACT
AIMS: Pancreatic polypeptide (PP) is elevated in people with vascular risk factors such as type 2 diabetes or increased visceral fat. We investigated potential relationships between PP and microvascular and macrovascular complications of diabetes. MATERIALS AND METHODS: Animal study: Subcutaneous PP infusion for 4 weeks in high fat diet mouse model. Retinal mRNA submitted for Ingenuity Pathway Analysis. Human study: fasting PP measured in 1478 participants and vascular complications recorded over median 5.5 (IQR 4.9-5.8) years follow-up. RESULTS: Animal study: The retinal transcriptional response to PP was indicative of cellular stress and damage, and this footprint matched responses described in previously published studies of retinal disease. Of mechanistic importance the transcriptional landscape was consistent with upregulation of folliculin, a recently identified susceptibility gene for diabetic retinopathy. Human study: Adjusting for established risk factors, PP was associated with prevalent and incident clinically significant retinopathy (odds ratio (OR) 1.289 (1.107-1.501) p = 0.001; hazard ratio (HR) 1.259 (1.035-1.531) p = 0.0213), albuminuria (OR 1.277 (1.124-1.454), p = 0.0002; HR 1.608 (1.208-2.141) p = 0.0011), and macrovascular disease (OR 1.021 (1.006-1.037) p = 0.0068; HR 1.324 (1.089-1.61), p = 0.0049), in individuals with type 2 diabetes, and progression to diabetes in non-diabetic individuals (HR 1.402 (1.081-1.818), p = 0.0109). CONCLUSIONS: Elevated fasting PP is independently associated with vascular complications of diabetes and affects retinal pathways potentially influencing retinal neuronal survival. Our results suggest possible new roles for PP-fold peptides in the pathophysiology of diabetes complications and vascular risk stratification.
