Endothelial microRNAs in INOCA patients with diabetes mellitus.

Ischemia with non-obstructive coronary artery (INOCA) is a common cause of hospital admissions, leading to negative outcomes and reduced quality of life. Central to its pathophysiology is endothelial dysfunction, which contributes to myocardial ischemia despite the absence of significant coronary artery blockage. Addressing endothelial dysfunction is essential in managing INOCA to alleviate symptoms and prevent cardiovascular events. Recent studies have identified diabetes mellitus (DM) as a significant factor exacerbating INOCA complications by promoting endothelial impairment and coronary microvascular dysfunction. MicroRNAs (miRNAs) have emerged as potential biomarkers and therapeutic targets in various biological processes, including endothelial dysfunction and cardiovascular diseases. However, research on miRNA biomarkers in INOCA patients is sparse. In this study, we examined a panel of circulating miRNAs involved in the regulation of endothelial function in INOCA patients with and without DM. We analyzed miRNA expression using RT-qPCR in a cohort of consecutive INOCA patients undergoing percutaneous coronary intervention. We detected a significant dysregulation of miR-363-5p and miR-92a-3p in INOCA patients with DM compared to those without DM, indicating their role as biomarkers for predicting and monitoring endothelial dysfunction in INOCA patients with DM.

Infiltrating macrophages amplify doxorubicin-induced cardiac damage: role of catecholamines.

BACKGROUND: The functional contribution of non-myocyte cardiac cells, such as inflammatory cells, in the setup of heart failure in response to doxorubicin (Dox) is recently becoming of growing interest. OBJECTIVES: The study aims to evaluate the role of macrophages in cardiac damage elicited by Dox treatment. METHODS: C57BL/6 mice were treated with one intraperitoneal injection of Dox (20 mg/kg) and followed up for 5 days by cardiac ultrasounds (CUS), histological, and flow cytometry evaluations. We also tested the impact of Dox in macrophage-depleted mice. Rat cardiomyoblasts were directly treated with Dox (D-Dox) or with a conditioned medium from cultured murine macrophages treated with Dox (M-Dox). RESULTS: In response to Dox, macrophage infiltration preceded cardiac damage. Macrophage depletion prevents Dox-induced damage, suggesting a key role of these cells in promoting cardiotoxicity. To evaluate the crosstalk between macrophages and cardiac cells in response to DOX, we compared the effects of D-Dox and M-Dox in vitro. Cell vitality was lower in cardiomyoblasts and apoptosis was higher in response to M-Dox compared with D-Dox. These events were linked to p53-induced mitochondria morphology, function, and autophagy alterations. We identify a mechanistic role of catecholamines released by Dox-activated macrophages that lead to mitochondrial apoptosis of cardiac cells through ß-AR stimulation. CONCLUSIONS: Our data indicate that crosstalk between macrophages and cardiac cells participates in cardiac damage in response to Dox.

Mitochondrial microRNAs Are Dysregulated in Patients with Fabry Disease.

Fabry disease (FD) is a lysosomal storage disorder caused by mutations in the gene for α-galactosidase A, inducing a progressive accumulation of globotriaosylceramide (GB3) and its metabolites in different organs and tissues. GB3 deposition does not fully explain the clinical manifestations of FD, and other pathogenetic mechanisms have been proposed, requiring the identification of new biomarkers for monitoring FD patients. Emerging evidence suggests the involvement of mitochondrial alterations in FD. Here, we propose mitochondrial-related microRNAs (miRs) as potential biomarkers of mitochondrial involvement in FD. Indeed, we demonstate that miRs regulating different aspects of mitochondrial homeostasis including expression and assembly of respiratory chain, mitogenesis, antioxidant capacity, and apoptosis are consistently dysregulated in FD patients. Our data unveil a novel noncoding RNA signature of FD patients, indicating mitochondrial-related miRs as new potential pathogenic players and biomarkers in FD. SIGNIFICANCE STATEMENT: This study demonstrates for the first time that a specific signature of circulating mitochondrial miRs (mitomiRs) is dysregulated in FD patients. MitomiRs regulating fundamental aspects of mitochondrial homeostasis and fitness, including expression and assembly of the respiratory chain, mitogenesis, antioxidant capacity, and apoptosis are significantly dysregulated in FD patients. Taken together, these new findings introduce mitomiRs as unprecedented biomarkers of FD and point at mitochondrial dysfunction as a novel potential mechanistic target for therapeutic approaches.

Autocrine Bradykinin Release Promotes Ischemic Preconditioning-Induced Cytoprotection in Bovine Aortic Endothelial Cells.

The aims of this study were to assess whether ischemic preconditioning (PC) induces bradykinin (Bk) synthesis in bovine aortic endothelial cells (bAECs) and, if so, to explore the molecular mechanisms by which this peptide provides cytoprotection against hypoxia. PC was induced by exposing bAECs to three cycles of 15 min of hypoxia followed by 15 min of reoxygenation. Bk synthesis peaked in correspondence to the early and late phases of PC (10-12 M and 10-11 M, respectively) and was abolished by a selective tissue kallikrein inhibitor, aprotinin. Stimulation with exogenous Bk at concentrations of 10-12 M and 10-11 M reduced the cell death induced by 12 h of hypoxia by 50%. Pretreatment with HOE-140, a Bk receptor 2 (BKR2) inhibitor, in bAECs exposed to 12 h of hypoxia, abrogated the cytoprotective effect of early and late PC, whereas des-Arg-HOE-140, a Bk receptor 1 (BKR1) inhibitor, affected only the late PC. In addition, we found that PC evoked endocytosis and the recycling of BKR2 during both the early and late phases, and that inhibition of these pathways affected PC-mediated cytoprotection. Finally, we evaluated the activation of PKA and Akt in the presence or absence of BKR2 inhibitor. HOE-140 abrogated PKA and Akt activation during both early and late PC. Consistently, BKR2 inhibition abolished cross-talk between PKA and Akt in PC. In bAECs, Bk-synthesis evoked by PC mediates the protection against both apoptotic and necrotic hypoxia-induced cell death in an autocrine manner, by both BKR2- and BKR1-dependent mechanisms.

Fatigue as hallmark of Fabry disease: role of bioenergetic alterations.

Fabry disease (FD) is a lysosomal storage disorder due to the impaired activity of the α-galactosidase A (GLA) enzyme which induces Gb3 deposition and multiorgan dysfunction. Exercise intolerance and fatigue are frequent and early findings in FD patients, representing a self-standing clinical phenotype with a significant impact on the patient's quality of life. Several determinants can trigger fatigability in Fabry patients, including psychological factors, cardiopulmonary dysfunctions, and primary alterations of skeletal muscle. The "metabolic hypothesis" to explain skeletal muscle symptoms and fatigability in Fabry patients is growing acknowledged. In this report, we will focus on the primary alterations of the motor system emphasizing the role of skeletal muscle metabolic disarrangement in determining the altered exercise tolerance in Fabry patients. We will discuss the most recent findings about the metabolic profile associated with Fabry disease offering new insights for diagnosis, management, and therapy.

Cardiopulmonary determinants of reduced exercise tolerance in Fabry disease.

Fabry disease (FD), also known as Anderson-Fabry disease, is a hereditary disorder of glycosphingolipid metabolism, caused by a deficiency of the lysosomal alpha-galactosidase A enzyme. This causes a progressive accumulation of glycosphingolipids in tissues and organs which represents the main pathogenetic mechanism of FD. The disease is progressive and multisystemic and is characterized by early symptoms and late complications (renal, cardiac and neurological dysfunction). Fatigue and exercise intolerance are early common symptoms in FD patients but the specific causes are still to be defined. In this narrative review, we deal with the contribution of cardiac and pulmonary dysfunctions in determining fatigue and exercise intolerance in FD patients.

Experimental evidence and clinical implications of Warburg effect in the skeletal muscle of Fabry disease.

Skeletal muscle (SM) pain and fatigue are common in Fabry disease (FD). Here, we undertook the investigation of the energetic mechanisms related to FD-SM phenotype. A reduced tolerance to aerobic activity and lactate accumulation occurred in FD-mice and patients. Accordingly, in murine FD-SM we detected an increase in fast/glycolytic fibers, mirrored by glycolysis upregulation. In FD-patients, we confirmed a high glycolytic rate and the underutilization of lipids as fuel. In the quest for a tentative mechanism, we found HIF-1 upregulated in FD-mice and patients. This finding goes with miR-17 upregulation that is responsible for metabolic remodeling and HIF-1 accumulation. Accordingly, miR-17 antagomir inhibited HIF-1 accumulation, reverting the metabolic-remodeling in FD-cells. Our findings unveil a Warburg effect in FD, an anaerobic-glycolytic switch under normoxia induced by miR-17-mediated HIF-1 upregulation. Exercise-intolerance, blood-lactate increase, and the underlying miR-17/HIF-1 pathway may become useful therapeutic targets and diagnostic/monitoring tools in FD.

The Metabolic Role of GRK2 in Insulin Resistance and Associated Conditions.

Insulin resistance (IRES) is a pathophysiological condition characterized by the reduced response to insulin of several tissues, including myocardial and skeletal muscle. IRES is associated with obesity, glucose intolerance, dyslipidemia, and hypertension, evolves toward type 2 diabetes, and increases the risk of developing cardiovascular diseases. Several studies designed to explore the mechanisms involved in IRES allowed the identification of a multitude of potential molecular targets. Among the most promising, G Protein Coupled Receptor Kinase type 2 (GRK2) appears to be a suitable one given its functional implications in many cellular processes. In this review, we will discuss the metabolic role of GRK2 in those conditions that are characterized by insulin resistance (diabetes, hypertension, heart failure), and the potentiality of its inhibition as a therapeutic strategy to revert both insulin resistance and its associated phenotypes.

Effects of Chronic Supplementation of L-Arginine on Physical Fitness in Water Polo Players.

BACKGROUND: Ergogenic nutritional supplementation is sought by professional athletes for improving physical performance; nevertheless, scientific evidence to support the chronic use of L-Arginine among water polo players is missing. METHODS: Seventeen male professional water polo players were randomly assigned to assume 5 grams per day of L-Arginine (n = 9) or placebo (n = 8) for 4 weeks. The players' fitness level was assessed in the maximal speed swimming test. Ear lobe blood samples taken before and after the effort for serum lactate content were analyzed. A speed-to-lactate ratio was generated at the baseline and after 4 weeks of treatment. We also tested the effects of L-Arginine in vitro, measuring NO production, mitochondrial respiration, and gene expression in human fibroblasts. RESULTS: L-Arginine did not modify BMI, muscle strength, and maximal speed at 200 meters after 4 weeks. However, L-Arginine ameliorated oxidative metabolism to exercise as suggested by the statistically significant lower lactate-to-speed ratio, which was not observed in placebo-treated controls. In vitro, L-Arginine induced the expression of a key regulator of mitochondrial biogenesis (PGC1α) and genes encoding for complex I and increased the production of nitric oxide and the maximal oxygen consumption rate. CONCLUSIONS: Chronic L-Arginine is safe and effective in ameliorating the oxidative metabolism of professional water polo players, through a mechanism of enhanced mitochondrial function.

Serum Uric Acid and Left Ventricular Mass in Essential Hypertension.

Serum uric acid (sUA) has been associated with cardiovascular risk. Although the recent mechanistic hypothesis poses the basis for the association between sUA and left ventricular mass index (LVMi), the issue remains poorly investigated in a clinical setup. Through a retrospective analysis of the database of the departmental Hypertension Clinic of University Hospital of Salerno Medical School, we identified 177 essential hypertensives (age 60.3 ± 13.3 years; 85 men), free from uric acid-modulating medications and severe chronic kidney disease, and whose sUA values, anthropometric, clinical, and echocardiographic data were available. In the studied cohort, the average duration of hypertension was 8.4 ± 7.1 years. LVMi associated with classical determinants, such as age, blood pressure, and kidney function, although after multivariate correction, only age remained significant. Also, sUA correlated positively with LVMi, as well as body size, metabolism, and kidney function. In a multivariate analysis, sUA confirmed the independent association with LVMi. Also, levels of sUA >5.6 mg/dl are associated with larger cardiac size. We confirmed our data in a replicate analysis performed in a larger population (1,379 hypertensives) from an independent clinic. Our results demonstrate that sUA increases with LVMi, and a cutoff of 5.6 mg/dl predict larger LV sizes. Our data suggest that hyperuricemia might help to stratify the risk of larger cardiac size in hypertensives.

Exploiting GRK2 Inhibition as a Therapeutic Option in Experimental Cancer Treatment: Role of p53-Induced Mitochondrial Apoptosis.

The involvement of GRK2 in cancer cell proliferation and its counter-regulation of p53 have been suggested in breast cancer even if the underlying mechanism has not yet been elucidated. Furthermore, the possibility to pharmacologically inhibit GRK2 to delay cancer cell proliferation has never been explored. We investigated this possibility by setting up a study that combined in vitro and in vivo models to underpin the crosstalk between GRK2 and p53. To reach this aim, we took advantage of the different expression of p53 in cell lines of thyroid cancer (BHT 101 expressing p53 and FRO cells, which are p53-null) in which we overexpressed or silenced GRK2. The pharmacological inhibition of GRK2 was achieved using the specific inhibitor KRX-C7. The in vivo study was performed in Balb/c nude mice, where we treated BHT-101 or FRO-derived tumors with KRX-C7. In our in vitro model, FRO cells were unaffected by GRK2 expression levels, whereas BHT-101 cells were sensitive, thus suggesting a role for p53. The regulation of p53 by GRK2 is due to phosphorylative events in Thr-55, which induce the degradation of p53. In BHT-101 cells, the pharmacologic inhibition of GRK2 by KRX-C7 increased p53 levels and activated apoptosis through the mitochondrial release of cytochrome c. These KRX-C7-mediated events were also confirmed in cancer allograft models in nude mice. In conclusion, our data showed that GRK2 counter-regulates p53 expression in cancer cells through a kinase-dependent activity. Our results further corroborate the anti-proliferative role of GRK2 inhibitors in p53-sensitive tumors and propose GRK2 as a therapeutic target in selected cancers.