Plasma Mucin-1 as a Potential Biomarker for Diabetic Peripheral Neuropathy in Type 2 Diabetes

BACKGROUND: Diabetic peripheral neuropathy (DPN) is a major complication of type 2 diabetes mellitus (T2D) that reduces quality of life and increases the risk of foot ulcers and amputations. Early detection is essential, and blood-based biomarkers may support improved screening and timely intervention. This study aimed to identify novel circulating biomarkers for the identification of DPN in patients with T2D. METHODS: In the screening phase, plasma samples from 43 participants (10 healthy volunteers [HV], 20 T2D without complications, and 13 T2D with DPN) were analyzed using an antibody array targeting 310 proteins. Thirteen differentially expressed proteins were identified, and six hub proteins were selected through bioinformatic analysis. In the validation phase, plasma concentrations of the six proteins were measured by ELISA in 252 subjects (100 HV, 97 T2D without complications, and 55 T2D with DPN). Mucin-1 expression in sciatic nerves was further evaluated in db/db mice. RESULTS: Of the six hub proteins (TGFB1, MUC1, PF4, IL2RA, SELL, B2M), only mucin-1 showed a significant increase in the DPN group. Plasma mucin-1 positively correlated with MNSI scores and negatively with motor and sensory nerve conduction velocities. In db/db mice, sciatic nerve mucin-1 expression was elevated, while CD31 expression was reduced. CONCLUSIONS: Plasma mucin-1 is strongly associated with DPN in both humans and animals and may serve as a promising biomarker for the screening and early identification of DPN.