Potential role of circulating microRNAs as a biomarker for unexplained recurrent spontaneous abortion.

OBJECTIVE

To compare circulating microRNA (miRNA) profiles between unexplained recurrent spontaneous abortion (URSA) and normal early pregnancies (NEP) and to evaluate the potential role of circulating miRNA as a biomarker for URSA.

DESIGN

Laboratory study using human plasma samples.

SETTING

Special hospital and research institutes.

PATIENT(S): From September 2012 to April 2013, samples of plasma were obtained from 27 URSA patients and 28 NEP patients at 6-10 weeks of gestation at the Department of Reproductive Immunology in Family Planning Special Hospital of Guangdong Province.

INTERVENTION(S): Differential miRNA profiling analysis of plasma collected from URSA and NEP patients was performed with the use of microarray.

MAIN OUTCOME MEASURE(S): The circulating miRNA expression profile was assessed by means of microarray and real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR) analysis.

RESULT(S): Twenty-five circulating miRNAs were expressed differentially in URSA compared with NEP. Of these, nine were overexpressed and 16 down-regulated. Six differentially expressed circulating miRNAs were selected to validate the microarray results, and qRT-PCR data confirmed the reliability of the microarray results. Further analysis showed that four circulating miRNAs (miR-320b, miR-146b-5p, miR-221-3p, miR-559) were up-regulated. In URSA, one circulating miRNA (miR-101-3p) was down-regulated in other larger scale samples according to qRT-PCR. Based on target gene analysis, we speculate that these circulating miRNAs regulate URSA by targeting immune, apoptosis, and angiogenic gene functions.

CONCLUSION(S): Circulating microRNAs may be involved in URSA pathogenesis and provide a promising new diagnostic biomarker for URSA.