Serum and exosomal hsa_circ_0000907 and hsa_circ_0057362 as novel biomarkers in the early diagnosis of diabetic foot ulcer.

OBJECTIVE: Diabetic foot ulcer (DFU) is a serious chronic complication leading to disability and death in patients suffering from diabetes. Currently, there is no effective marker for its early diagnosis. The aim of this study is to analyze the difference of circRNA expression profiles between DFU and normal human wounds (NHW) and to screen serum biomarkers for the early diagnosis of DFU.

MATERIALS AND METHODS: Differentially expressed circRNAs were screened by bioinformatics analysis, using GSE114248 chip data downloaded from GEO database, including 5 pairs of tissue samples from DFU patients and NHW cases. Accordingly, 20 cases of DFU (Wagner grade 0~2), 20 non-DFU diabetes and 20 healthy controls were selected in the screening test, and the total RNAs of serum and serum-derived exosomes were extracted. The screened circRNAs were verified in the third largest cohort, and the ROC curves were drawn to assess the diagnostic efficiency.

RESULTS: As discovered by experiment, there were a total of 67 circRNAs presented differential expressions between the two groups, with 28 circRNAs upregulated and 39 circRNAs downregulated in DFU group. Two types of circRNAs, hsa_circ_0000907 and hsa_circ_0057362, were selected as candidate biomarkers in current study and validated in a large cohort. The AUCs of serum hsa_circ_0000907 and hsa_circ_0057362 to diagnose early DFU were 0.9389 and 0.8792, respectively, and the AUCs of exosomal hsa_circ_0000907 and hsa_circ_0057362 to diagnose early DFU were 0.8783 and 0.8481, respectively. Furthermore, the expressions of serum hsa_circ_0000907 and hsa_circ_0057362 were negatively correlated with ankle brachial index (ABI) and transcutaneous oxygen pressure (TcPO2) in DFU patients.

CONCLUSIONS: Serum and exosomal hsa_circ_0000907 and hsa_circ_0057362, especially hsa_circ_0000907, have novel diagnostic capabilities in the early diagnosis of DFU.