Circular RNAs (
circRNAs) are an abundant class of endogenous non‑coding RNAs and are associated with numerous diseases, including
cancer,
cardiovascular diseases, and type 2
diabetes mellitus (T2DM). However, the association between
circRNAs and
inflammation or inflammatory
cytokines in patients with T2DM remains to be fully elucidated. The purpose of the present study was to investigate the expression profiles of
circRNAs in peripheral leucocytes of patients with T2DM and their association with inflammatory
cytokines. Peripheral blood from patients with T2DM (n=43) and healthy individuals (n=45) were collected for
RNA sequencing and later verification. Reverse transcription‑polymerase chain reaction (RT‑PCR) and reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) analyses were used to detect the expression levels of
circRNAs. The expression of inflammatory factors, including
interleukin (IL)‑1, (IL)‑6, and
tumor necrosis factor (TNF)‑α were measured via enzyme‑linked
immunosorbent assay. Furthermore, the
mRNA expression level of ankyrin repeat domain 36 (ANKRD36), a
protein located at 2q11.2 that interacts with the GAPDH gene, was measured using RT‑qPCR analysis. The
circRNA/
microRNA (
miRNA) interaction was predicted using RegRNA and mirPath software. In total, 220
circRNAs were found to be differentially expressed between patients with T2DM and healthy individuals, of which 107 were upregulated and 113 were downregulated. Among the nine selected
circRNAs, circANKRD36 was significantly upregulated in patients with T2DM compared with control subjects (P=0.02). The expression level of circANKRD36 was positively correlated with
glucose and
glycosylated hemoglobin (r=0.3250, P=0.0047 and r=0.3171, P=0.0056, respectively). The expression level of IL‑6 was significantly different between the T2DM group and control group (P=0.028) and was positively correlated with circANKRD36. The difference of circANKRD36 host gene expression between patients with T2DM and healthy controls was significant (P=0.04). Taken together, circANKRD36 may be involved in T2DM and inflammation‑associated pathways via interaction with
miRNAs, including hsa‑miR‑3614‑3p, hsa‑miR‑498, and hsa‑miR‑501‑5p. The expression of circANKRD36 was up-regulated in peripheral blood leucocytes and was correlated with chronic
inflammation in T2DM. Therefore, circANKRD36 can be used as a potential
biomarker for screening chronic
inflammation in patients with T2DM.