In a previous post discussing MicroRNAs (miRNAs) (MicroRNAs and biliary atresia), I stated that “Despite this intriguing research, it not clear whether or when miRNAs will have an important role in bedside management.” Well, as more articles emerge on miRNAs, it is becoming clear that miRNAs will have a role in clinical medicine; the questions are when and what cost.
The latest study (J Allergy Clin Immunol 2012; 129: 1064-75) by Lu et al from Cincinnati shows how this technique can identify a specific signature for eosinophilic esophagitis (EoE) and how miRNAs can serve as a biomarker for disease response. The investigators took plasma and esophageal biopsy specimens from patients with EoE, reflux esophagitis, and healthy controls; they used an array comprising 677 miRNAs. 254 miRNAs were expressed at greater than background levels, but 21 upregulated miRNAs and 11 downregulated miRNAs were markedly different.
To quickly understand how useful this technology could become requires a glance at the “heat maps” showing the expression profile of the 21 upregulated miRNAs and the 11 downregulated miRNAs, comparing EoE with healthy controls (Figures 1 & 3). In addition, in Figure 3, it is readily apparent that the expression pattern is completely different from reflux esophagitis. Furthermore, this figure demonstrates visually a normal-appearing pattern in patients who respond to fluticasone.
Other figures in the article and in the appendix demonstrate the complex relationships between these specific miRNAs and target genes.
- miRNAs from tissue or blood could serve as biomarkers for the presence of EoE and response to therapy
- Of the identified miRNAs, miR-21 and miR-223 strongly correlate with esophageal eosinophilia as well as previously described EoE transcriptome
- Plasma miRNAs that are most differentiated in EoE include miR-146a, miR-146b, and miR-223.