MicroRNA expression analysis in peripheral blood and soft-tissue of patients with periprosthetic hip infection

Abstract

Aims: Current diagnostic tools are not always able to effectively identify periprosthetic joint infections (PJIs). Recent studies suggest that circulating microRNAs (miRNAs) undergo changes under pathological conditions such as infection. The aim of this study was to analyze miRNA expression in hip arthroplasty PJI patients.

Methods: This was a prospective pilot study, including 24 patients divided into three groups, with eight patients each undergoing revision of their hip arthroplasty due to aseptic reasons, and low- and high-grade PJI, respectively. The number of intraoperative samples and the incidence of positive cultures were recorded for each patient. Additionally, venous blood samples and periarticular tissue samples were collected from each patient to determine miRNA expressions between the groups. MiRNA screening was performed by small RNA-sequencing using the miRNA next generation sequencing (NGS) discovery (miND) pipeline.

Results: Overall, several miRNAs in plasma and tissue were identified to be progressively deregulated according to ongoing PJI. When comparing the plasma samples, patients with a high-grade infection showed significantly higher expression levels for hsa-miR-21-3p, hsa-miR-1290, and hsa-miR-4488, and lower expression levels for hsa-miR-130a-3p and hsa-miR-451a compared to the aseptic group. Furthermore, the high-grade group showed a significantly higher regulated expression level of hsa-miR-1260a and lower expression levels for hsa-miR-26a-5p, hsa-miR-26b-5p, hsa-miR-148b-5p, hsa-miR-301a-3p, hsa-miR-451a, and hsa-miR-454-3p compared to the low-grade group. No significant differences were found between the low-grade and aseptic groups. When comparing the tissue samples, the high-grade group showed significantly higher expression levels for 23 different miRNAs and lower expression levels for hsa-miR-2110 and hsa-miR-3200-3p compared to the aseptic group. No significant differences were found in miRNA expression between the high- and low-grade groups, as well as between the low-grade and aseptic groups.

Conclusion: With this prospective pilot study, we were able to identify a circulating miRNA signature correlating with high-grade PJI compared to aseptic patients undergoing hip arthroplasty revision. Our data contribute to establishing miRNA signatures as potential novel diagnostic and prognostic biomarkers for PJI.

Fig. 1

Scatterplots depicting the levels of a) upregulated and b) downregulated micro RNAs (miRNAs) in plasma samples of high-grade (green) vs aseptic (red) group. CPM, counts per million.

Fig. 2

Scatterplots depicting the levels of a) upregulated and b) downregulated micro RNAs (miRNAs) in plasma samples of high- (red) vs low-grade (green) group. CPM, counts per million.

Fig. 3

Scatterplots depicting the levels of a) upregulated (top 12 by logFC) and b) downregulated micro RNAs (miRNAs) in tissue samples of high-grade (green) vs aseptic (red) group. CPM, counts per million.

Fig. 4

a) This heatmap is for only the top 50 micro RNAs (miRNAs) (based on coefficient of variation (CV%)). An additional filter was introduced to increase the robustness: only miRNAs that showed reads assigned per million (RPM) in at least 1 /n (groups) percent of samples (e.g. with four groups, the miRNA has to have an RPM value above five in at least 25% of the samples). This removed miRNAs that had a high CV, but were only expressed in a too small amount of samples to have any statistical significance or biological relevance. b) A total of 341 miRNAs were shown in the other heatmap, based on the same filters described for the top 50 miRNAs. On the x-axis, plasma and tissue samples are depicted, whereas on the y-axis, the detected miRNAs are illustrated. On the top of the heatmaps, scale bar with plasma (red) and tissue (green) sections is demonstrated.