Marathon-Induced Cardiac Strain as Model for the Evaluation of Diagnostic microRNAs for Acute Myocardial Infarction.

BACKGROUND: The current gold standard biomarker for myocardial infarction (MI), cardiac troponin (cTn), is recognized for its high sensitivity and organ specificity; however, it lacks diagnostic specificity. Numerous studies have introduced circulating microRNAs as potential biomarkers for MI. This study investigates the MI-specificity of these serum microRNAs by investigating myocardial stress/injury due to strenuous exercise. METHODS: MicroRNA biomarkers were retrieved by comprehensive review of 109 publications on diagnostic serum microRNAs for MI. MicroRNA levels were first measured by next-generation sequencing in pooled sera from runners (n = 46) before and after conducting a full competitive marathon. Hereafter, reverse transcription quantitative real-time PCR (qPCR) of 10 selected serum microRNAs in 210 marathon runners was performed (>10,000 qPCR measurements). RESULTS: 27 potential diagnostic microRNA for MI were retrieved by the literature review. Eight microRNAs (miR-1-3p, miR-21-5p, miR-26a-5p, miR-122-5p, miR-133a-3p, miR-142-5p, miR-191-5p, miR-486-3p) showed positive correlations with cTnT in marathon runners, whereas two miRNAs (miR-134-5p and miR-499a-5p) showed no correlations. Upregulation of miR-133a-3p (p = 0.03) and miR-142-5p (p = 0.01) went along with elevated cTnT after marathon. CONCLUSION: Some MI-associated microRNAs (e.g., miR-133a-3p and miR-142-5p) have similar kinetics under strenuous exercise and MI as compared to cTnT, which suggests that their diagnostic specificity could be limited. In contrast, several MI-associated microRNAs (miR-26a-5p, miR-134-5p, miR-191-5p) showed different release behavior; hence, combining cTnT with these microRNAs within a multi-marker strategy may add diagnostic accuracy in MI.

Epigenetic Regulation of Alternative mRNA Splicing in Dilated Cardiomyopathy.

In recent years, the genetic architecture of dilated cardiomyopathy (DCM) has been more thoroughly elucidated. However, there is still insufficient knowledge on the modifiers and regulatory principles that lead to the failure of myocardial function. The current study investigates the association of epigenome-wide DNA methylation and alternative splicing, both of which are important regulatory principles in DCM. We analyzed screening and replication cohorts of cases and controls and identified distinct transcriptomic patterns in the myocardium that differ significantly, and we identified a strong association of intronic DNA methylation and flanking exons usage (p < 2 × 10-16). By combining differential exon usage (DEU) and differential methylation regions (DMR), we found a significant change of regulation in important sarcomeric and other DCM-associated pathways. Interestingly, inverse regulation of Titin antisense non-coding RNA transcript splicing and DNA methylation of a locus reciprocal to TTN substantiate these findings and indicate an additional role for non-protein-coding transcripts. In summary, this study highlights for the first time the close interrelationship between genetic imprinting by DNA methylation and the transport of this epigenetic information towards the dynamic mRNA splicing landscape. This expands our knowledge of the genome-environment interaction in DCM besides simple gene expression regulation.

Two Hearts at Risk: Emergency Alcohol Septal Ablation in a Pregnant Woman With Decompensated HOCM.

Hypertrophic obstructive cardiomyopathy (HOCM) increases the risk for mother and fetus during pregnancy. Alcohol septal ablation (ASA) is an established procedure in nonpregnant patients with HOCM. In this report, we present a case of a 29-year-old woman in her 29th gestational week with decompensated HOCM undergoing a successful ASA. (Level of Difficulty: Advanced.).

Cardiac Myxoma in a Patient With Hypertrophic Cardiomyopathy.

We report a rare case of concomitant hypertrophic cardiomyopathy and cardiac myxoma without LEOPARD syndrome. Additionally, 6 similar cases were systemically reviewed, and the characteristics of this first-ever studied patient group were summarized. (Level of Difficulty: Beginner.).

The chameleon of cardiology: cardiac sarcoidosis before and after heart transplantation.

Cardiac sarcoidosis is a chronic inflammatory disease with a large spectrum of symptoms that can mimic diseases such as dilated, hypertrophic, or arrhythmogenic cardiomyopathies. It can be asymptomatic but can also present with ventricular arrhythmias, conduction disease, and heart failure (HF) or even sudden cardiac death (SCD). We present here the case of a patient transplanted due to end-stage arrhythmogenic right ventricular cardiomyopathy (ARVC), fulfilling the task force criteria. A few years after successful heart transplantation (HTX), the patient developed similar symptoms and morphofunctional changes of the heart, which led to critical re-evaluation of his primary diagnosis.

microRNA assays for acute coronary syndromes.

microRNAs are promising biomarkers for diverse cardiovascular diseases. While quantification of the small non-coding RNAs is routinely performed in the research laboratory, clinical-grade assessment of microRNAs in central laboratory environments or point-of-care testing is still in its infancy. In this review, we provide an overview on microRNAs as biomarkers for acute coronary syndromes and highlight promising technical approaches for microRNA-based assays systems.