A Novel Circulating MicroRNA for the Detection of Acute Myocarditis

BACKGROUND

The diagnosis of acute myocarditis typically requires either endomyocardial biopsy (which is invasive) or cardiovascular magnetic resonance imaging (which is not universally available). Additional approaches to diagnosis are desirable. We sought to identify a novel microRNA for the diagnosis of acute myocarditis.

METHODS

To identify a microRNA specific for myocarditis, we performed microRNA microarray analyses and quantitative polymerase-chain-reaction (qPCR) assays in sorted CD4+ T cells and type 17 helper T (Th17) cells after inducing experimental autoimmune myocarditis or myocardial infarction in mice. We also performed qPCR in samples from coxsackievirus-induced myocarditis in mice. We then identified the human homologue for this microRNA and compared its expression in plasma obtained from patients with acute myocarditis with the expression in various controls.

RESULTS

We confirmed that Th17 cells, which are characterized by the production of interleukin-17, are a characteristic feature of myocardial injury in the acute phase of myocarditis. The microRNA mmu-miR-721 was synthesized by Th17 cells and was present in the plasma of mice with acute autoimmune or viral myocarditis but not in those with acute myocardial infarction. The human homologue, designated hsa-miR-Chr8:96, was identified in four independent cohorts of patients with myocarditis. The area under the receiver-operating-characteristic curve for this novel microRNA for distinguishing patients with acute myocarditis from those with myocardial infarction was 0.927 (95% confidence interval, 0.879 to 0.975). The microRNA retained its diagnostic value in models after adjustment for age, sex, ejection fraction, and serum troponin level.

CONCLUSIONS

After identifying a novel microRNA in mice and humans with myocarditis, we found that the human homologue (hsa-miR-Chr8:96) could be used to distinguish patients with myocarditis from those with myocardial infarction. (Funded by the Spanish Ministry of Science and Innovation and others.).

Sun exposure influences the prognostic power of components of mineral metabolism in patients with coronary artery disease

BACKGROUND AND AIM

Calcidiol (vitamin D metabolite) plasma levels vary with sun exposure (SE). However, it is not known if SE influences its prognostic ability. We have studied the effect of SE on plasma levels of the components of mineral metabolism (calcidiol, fibroblast growth factor-23 [FGF-23], parathormone [PTH], and phosphate [P]) and on their prognostic value in patients with coronary artery disease (CAD).

METHODS AND RESULTS

We studied prospectively 704 patients with stable CAD. Clinical variables and baseline calcidiol, FGF-23, PTH, and P plasma levels were assessed. We divided the population in two subgroups, according to the period of plasma extraction: High SE (HSE) (April-September) and low SE (LSE) (October-March). The outcome was the development of acute ischemic events (acute coronary syndrome, stroke, or transient ischemic attack), heart failure, or death. Mean follow-up was 2.15 ± 0.99 years. Calcidiol and P levels were higher in HSE group. In the whole population, calcidiol (HR = 0.84 for each 5 ng/ml increase, 95% CI = 0.71-0.99; p = 0.038) and FGF-23 (HR = 1.14 for each 100 RU/ml increase, 95% CI = 1.05-1.23; p = 0.009) were predictors of the outcome, along with age, hypertension, body-mass index, peripheral artery disease, and P levels. In the LSE subgroup, calcidiol (HR = 0.75; 95% CI = 0.57-0.99; p = 0.034) and FGF-23 (HR = 1.34; 95% CI = 1.13-1.58; p = 0.003) remained as predictors of the outcome. In the HSE group calcidiol and FGF-23 had not independent prognostic value.

CONCLUSIONS

In patients with stable CAD, low calcidiol and high FGF-23 plasma levels predict an adverse prognosis only when the sample is obtained during the months with LSE. SE should be taken into account in the clinical practice.