Circulating miRNAs are associated with frailty and ST-elevation myocardial infarction pathways

Atheroprotective roles of exercise-regulated microRNAs

Cardiovascular disease remains the leading cause of death worldwide, with atherosclerosis (AS) serving as a critical underlying pathological process and major risk factor. Regular physical exercise is widely recognized as an effective strategy to reduce the risks and severity of AS, yet the precise molecular mechanisms through which exercise exerts its protective effects are still not fully understood. MicroRNAs (miRNAs), key regulators of gene expression, play integral roles in the progression of AS by influencing vascular function, lipid metabolism, and inflammation. The exercise-induced improvement of AS is a complex process, with miRNAs playing essential roles not only within cells and tissues but also circulating stably in the bloodstream as novel signaling molecules. These circulating miRNAs mediate communication between organs and tissues, acting as potential biomarkers that could provide deeper, systemic insights into the metabolic benefits of exercise. In this review, we explore recent advancements in our understanding of how exercise affects both intracellular and circulating miRNAs. We emphasize how exercise-regulated miRNAs contribute to endothelial function, promote lipid metabolism across various metabolic organs, and reduce monocyte-mediated systemic inflammation, while also addressing their role in alleviating frailty. Circulating miRNAs, which dynamically reflect tissue-specific responses to exercise, hold great promise as diagnostic and prognostic biomarkers for AS. Moreover, we discuss the challenges and future directions in this field, aiming to uncover how exercise-induced miRNA modulation could offer innovative therapeutic strategies for the prevention and treatment of AS.

Forensic significance of intracardiac expressions of Nrf2 in acute myocardial ischemia

When exposed to oxidative and electrophilic stress, a protective antioxidant response is initiated by nuclear factor erythroid 2-related factor 2 (Nrf2). However, the extent of its importance in the forensic diagnosis of acute ischemic heart diseases (AIHD), such as myocardial infarction (MI), remains uncertain. On the other hand, immunohistochemical analyses of fibronectin (FN) and the terminal complement complex (C5b-9) prove valuable in identifying myocardial ischemia that precedes necrosis during the postmortem diagnosis of sudden cardiac death (SCD). In this study, we investigated the immunohistochemical levels of Nrf2, FN, and C5b-9 in human cardiac samples to explore their forensic relevance for the identification of acute cardiac ischemia. Heart samples were obtained from 25 AIHD cases and 39 non-AIHD cases as controls. Nrf2 was localized in the nuclei of cardiomyocytes, while FN and C5b-9 were detected in the myocardial cytoplasm. The number of intranuclear Nrf2 positive signals in cardiomyocytes increased in AIHD cases compared to control cases. Additionally, the grading of positive portions of cardiac FN and C5b-9 in the myocardium was also significantly enhanced in AIHD, compared to controls. Collectively, these results indicate that the immunohistochemical investigation of Nrf2 combined with FN, and/or C5b-9 holds the potential for identifying early-stage myocardial ischemic lesions in cases of SCD.

miRNA Dysregulation in Cardiovascular Diseases: Current Opinion and Future Perspectives

MicroRNAs (miRNAs), small noncoding RNAs, are post-transcriptional gene regulators that can promote the degradation or decay of coding mRNAs, regulating protein synthesis. Many experimental studies have contributed to clarifying the functions of several miRNAs involved in regulatory processes at the cardiac level, playing a pivotal role in cardiovascular disease (CVD). This review aims to provide an up-to-date overview, with a focus on the past 5 years, of experimental studies on human samples to present a clear background of the latest advances to summarize the current knowledge and future perspectives. SCOPUS and Web of Science were searched using the following keywords: (miRNA or microRNA) AND (cardiovascular diseases); AND (myocardial infarction); AND (heart damage); AND (heart failure), including studies published from 1 January 2018 to 31 December 2022. After an accurate evaluation, 59 articles were included in the present systematic review. While it is clear that miRNAs are powerful gene regulators, all the underlying mechanisms remain unclear. The need for up-to-date data always justifies the enormous amount of scientific work to increasingly highlight their pathways. Given the importance of CVDs, miRNAs could be important both as diagnostic and therapeutic (theranostic) tools. In this context, the discovery of “TheranoMIRNAs” could be decisive in the near future. The definition of well-setout studies is necessary to provide further evidence in this challenging field.