Heart failure (HF) is a clinical syndrome caused by structural and/or functional cardiac abnormalities, resulting in a reduced cardiac output and/or elevated intracardiac filling pressures at rest or during stress. HF is a major public health problem with high prevalence and incidence, involving both high morbidity and mortality, but also high economic costs. The incidence of HF progressively increases with age, reaching around 20% among people over 75 years old. Indeed, HF represents the leading cause of hospitalization in patients older than 65 years in Western countries. Hence, some authors even consider HF a geriatric syndrome, entailing worse prognosis and high residual disability, and often associating some complex comorbidities, common in older population, that may further complicate the course of the disease. On the other hand, however, clinical course and prognosis may be often difficult to predict. In this article, main pathophysiological issues related to the aging heart are addressed, together with key aspects related to both diagnosis and prognosis in elderly patients with HF. Besides, main geriatric conditions, common in the elderly population, are reviewed, highlighting the importance of a comprehensive and multidisciplinary approach.

 BACKGROUND  For patients with coronary heart disease, reperfusion treatment strategies are often complicated by ischemia/reperfusion (I/R) injury (IRI), leading to serious organ damage and malfunction. The miR-21/programmed cell death protein 4 (PDCD4) pathway is involved in the IRI of cardiomyocytes; however, the aberrant miR-21 expression remains unexplained. Therefore, this study aimed to explore whether circRNA_0031672 downregulates miR-21-5p expression during I/R and to determine whether miR-21-5p-expressing bone marrow mesenchymal stem cells (BMSCs) reduce myocardial IRI. METHODS  CircRNA_0031672, miR-21-5p, and PDCD4 expressions were evaluated in the I/R rat model and hypoxia/re-oxygenation (H/R)-treated H9C2 cells. Their interactions were subsequently investigated using luciferase reporter and RNA pulldown assays. Methyltransferase-like 3, a methyltransferase catalyzing N6-methyladenosine (m6A), was overexpressed in H9C2 cells to determine whether m6A modification influences miR-21-5p targeting PDCD4. BMSCs stably expressing miR-21 were co-cultured with H9C2 cells to investigate the protective effect of BMSCs on H9C2 cells upon H/R. RESULTS  I/R downregulated miR-21-5p expression and upregulated circRNA_0031672 and PDCD4 expressions. CircRNA_0031672 knockdown increased miR-21-5p expression, but repressed PDCD4 expression, indicating that circRNA_0031672 competitively bound to miR-21-5p and prevented it from targeting PDCD4 mRNA. The m6A modification regulated PDCD4 expression, but had no effect on miR-21-5p targeting PDCD4. The circRNA_0031672/miR-21-5p/PDCD4 axis regulated myocardial cells viability and apoptosis after H/R treatment; co-culture with miR-21-5p-expressing BMSCs restored miR-21-5p abundance in H9C2 cells and further reduced H9C2 cells apoptosis induced by H/R. CONCLUSIONS  We identified a novel circRNA_0031672/miR-21-5p/PDCD4 signaling pathway that mediates the apoptosis of cardiomyocytes and successfully alleviates IRI in myocardial cells by co-culture with miR-21-5p-expressing BMSCs, offering novel insights into the IRI pathogenesis in cardiovascular diseases.