Context: There is an unmet need for biomarkers of pancreatic beta-cell death to improve early diagnosis of type 1 diabetes, enroll subjects into clinical trials, and assess treatment response. To address this need, several groups developed assays measuring insulin deoxyribonucleic acid (DNA) with unmethylated CpG sites in cell-free DNA. Unmethylated insulin DNA should be derived predominantly from beta-cells and indicate ongoing beta-cell death. Objective: To assess the performance of three unmethylated insulin DNA assays. Design and Participants: Plasma or serum samples from 13 subjects undergoing total pancreatectomy and islet autotransplantation were coded and provided to investigators to measure unmethylated insulin DNA. Samples included a negative control taken post-pancreatectomy but pretransplant, and a positive control taken immediately following islet infusion. We assessed technical reproducibility, linearity, and persistence of detection of unmethylated insulin DNA for each assay. Results: All assays discriminated between the negative sample and samples taken directly from the islet transplant bag; 2 of 3 discriminated negative samples from those taken immediately after islet infusion. When high levels of unmethylated insulin DNA were present, technical reproducibility was generally good for all assays. Conclusions: The measurement of beta cell cell-free DNA, including insulin, is a promising approach, warranting further testing and development in those with or at-risk for type 1 diabetes, as well as in other settings where understanding the frequency or kinetics of beta cell death could be useful.
Bibliographical noteFunding Information:
Funding Statement: This research was performed using funding provided by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)-supported Human Islet Research Network Opportunity Pool Fund (HIRN, RRID:SCR_014393; https://hirnetwork.org; U01 DK104162 to CEM), and by JDRF under the Core for Assay Validation grants #3-SRA-2016-209-Q-R to S. Alice Long and 3-SRA-2019-791-S-B to CS. KCH received support from R01 DK057846, UC4 DK104205-01, and R21 AI135562. KCH and SUB have support from R43 DK116577. Dr. Bellin is supported by R01 DKI09914.
© 2020 Endocrine Society 2020.
- Beta cell
- cell-free DNA
- islet transplantation
- type 1 diabetes