Background: Long-term complications of type 2 diabetes (T2D) are the major causes for T2D-related disability and mortality. Notably, diabetic nephropathy (DN) has become the most frequent cause of end-stage renal disease in most countries. A clinically convenient, noninvasive approach for monitoring the development of DN would improve the overall life quality of patients with T2D and help reduce healthcare burden through preventive interventions.

Methods: A selective chemical labeling strategy, the 5hmC-Seal, was used to profile genome-wide 5-hydroxymethylcytosines (5hmC), an emerging class of epigenetic markers implicated in complex diseases including diabetes, in patient-derived circulating cell-free DNA (cfDNA) in plasma. Differentially modified 5hmC marker genes were identified through the pair-wise comparisons among T2D patients with DN (DN) (n=12), T2D patients with non-DN complications(non-DN) (n=29), and T2D controls with no complications (T2D) (n=14),respectively.

Results: A panel of 271 differentially modified genes (fold-change > 10% and nominal p-value < 0.05) were detected between T2D and DN, involving genes and pathways relevant to synthesis of bile acids and bile salts, fatty acid metabolism(ACAA2), mitochondrial gene expression (POLRMT), and ion transport (OTX1, SRI). In addition, a 4-gene 5hmC marker panel (DNAH1, RAB11FIP4, POLRMT, RAB36) was found to be differentially modified among T2D, DN and non-DN patients. Further analysis indicated that this 4-gene signature showed capacity for differentiating DN from T2D (AUC= 83%; 95% confidence interval [66-100%]), healthy individuals (AUC= 83% [64-100%]), and non-DN (AUC = 88% [76-100%]).

Conclusion: The 5hmC profiles in cfDNA reflect epigenetic changes in T2D and DN that have the potential to be a clinically convenient, noninvasive approach for monitoring the presence and severity of diabetic retinopathy in high risk T2D patients.


C. Zeng: None. Y. Yang: None. Z. Zhang: None. C. He: Advisory Panel; Self; Shanghai Epican Genetech Co., Ltd. W. Zhang: Advisory Panel; Self; Shanghai Epican Genetech Co., Ltd. S. Liu: None.

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