Deciphering the Plasma Proteome of Type 2 Diabetes

With an estimated prevalence of 463 million affected, type 2 diabetes represents a major challenge to health care systems worldwide. Analyzing the plasma proteomes of individuals with type 2 diabetes may illuminate hitherto unknown functional mechanisms underlying disease pathology. We assessed the associations between type 2 diabetes and >1000 plasma proteins in the KORA (Cooperative health research in the Region of Augsburg) F4 cohort (n=993, 110 cases), with subsequent replication in the HUNT3 (Third wave of the Nord-Trøndelag Health Study) cohort (n=940, 149 cases). We computed logistic regression models adjusted for age, sex, BMI, smoking status and hypertension. Additionally, we investigated associations with incident type 2 diabetes and performed two-sample bi-directional Mendelian randomization (MR) analysis to prioritize our results. Association analysis of prevalent type 2 diabetes revealed 24 replicated proteins, of which eight are novel. Proteins showing association with incident type 2 diabetes were aminoacylase-1, growth hormone receptor, and insulin-like growth factor binding protein-2. Aminoacylase-1 was associated with both prevalent and incident type 2 diabetes. MR analysis yielded nominally significant causal effects of type 2 diabetes on cathepsin Z and rennin, both known to have roles in the pathophysiological pathways of cardiovascular disease, and of sex hormone-binding globulin on type 2 diabetes. In conclusion, our high-throughput proteomics study replicated previously reported type 2 diabetes-protein associations, and identified new candidate proteins possibly involved in the pathogenesis of type 2 diabetes.