New Assay Rapidly Detects Misfolded Insulin, A Potential Diabetes Biomarker

Misfolded proteins are a hallmark of many amyloid diseases, where proteins aggregate and cause cellular damage. While often associated with neurodegenerative conditions like Alzheimer's disease, protein misfolding can also impact metabolic hormones like insulin, potentially contributing to diabetes complications or even specific forms of diabetes mellitus. Current methods for detecting misfolded insulin are often time-consuming or lack the necessary sensitivity for early diagnosis. This study addresses the urgent need for a highly sensitive and rapid diagnostic tool to identify misfolded insulin protein.

The developed RT-QuIC assay demonstrated exceptional sensitivity and specificity for detecting misfolded insulin. The assay was able to detect misfolded insulin seeds at concentrations as low as 10 femtomolar (fM), achieving a 95% detection rate within 12 hours for samples containing 100 fM misfolded insulin. In comparison, control samples containing only properly folded insulin showed no significant signal amplification over the 48-hour period, indicating 100% specificity against native insulin. Furthermore, the assay successfully distinguished misfolded insulin in simulated biological matrices, showing a 2.3-fold faster detection time compared to traditional ELISA methods for equivalent concentrations. The signal intensity from misfolded samples was consistently 5-fold higher than background noise, with a p<0.001 significance. The assay was able to detect misfolded insulin seeds at concentrations as low as 10 femtomolar (fM), achieving a 95% detection rate within 12 hours for samples containing 100 fM misfolded insulin.