A Pilot Study of Circulating microRNA Expression in Newly Diagnosed Type 2 Diabetes Using a Pooled Sample Approach.

Background and

Objectives

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression and have emerged as potential biomarkers in type 2 diabetes mellitus and its complications. This pilot exploratory study aimed to identify circulating miRNAs with differential expression in plasma from patients with newly diagnosed type 2 diabetes mellitus compared to age- and sex-matched healthy controls. Materials and

Methods

Peripheral venous blood samples were collected from diabetic patients (n = 24) and controls (n = 12). Due to the exploratory nature of the study and limited sample material, samples were pooled within each group prior to plasma separation. Total RNA, including miRNAs, was extracted from plasma and analyzed using a high-throughput qPCR panel. Two normalization methods were applied to assess miRNA expression, and overlapping results were used for downstream analysis. Fold regulation was calculated using the 2^(-ΔCt) method.

Results

A total of 33 and 42 miRNAs were identified as differentially expressed using the first and second normalization methods, respectively. Fourteen miRNAs were consistently downregulated across both methods. Several of these miRNAs, including hsa-miR-26a-5p, hsa-miR-146a-5p, hsa-miR-186-5p, hsa-miR-19a-3p, and hsa-miR-652-3p, have been previously associated with glucose metabolism, inflammation, and diabetic complications, such as retinopathy, neuropathy, and endothelial dysfunction. The pooling strategy enabled an efficient exploratory assessment of miRNA expression patterns while reducing inter-individual variability.

Conclusions

This exploratory pilot study identifies a panel of circulating miRNAs with altered expression in pooled plasma samples from patients with newly diagnosed type 2 diabetes mellitus. These findings provide preliminary insights that warrant further validation in larger, individual-level studies to assess their diagnostic and prognostic potential.