Rosuvastatin Reduces L-Type Ca2+ Current and Alters Contractile Function in Cardiac Myocytes via Modulation of β-Adrenergic Receptor Signaling

Translational insights into statin-induced myotoxicity: Differential impact of lipophilic and hydrophilic statins on iPSC-derived skeletal muscle cells from patients with familial hypercholesterolemia

Statins are highly effective cholesterol-lowering drugs that can reduce the risk of cardiovascular events. Statins are well tolerated but some patients experience statin-associated muscle symptoms (SAM) that can reduce adherence to therapy. We investigated molecular mechanisms statin-induced myotoxicity using induced pluripotent stem cells (iPSC)-derived skeletal muscle (SKgM) cells. iPSC-SKgM cells were obtained from patients with familial hypercholesterolemia (FH) experiencing SAM (n = 3) or not (nonSAM, n = 3). iPSC-SkgM cells were treated with atorvastatin and rosuvastatin (1 to 100 µM). Statin cytotoxicity was assessed by functional assays (cell death, mitochondrial damage, caspase 3/7 activity). iPSC-SkgM cells from SAM patients were more sensitive to atorvastatin toxicity than nonSAM cells (p < 0.05), recapitulating the phenotype of SAM patients. Rosuvastatin was less cytotoxic than atorvastatin in iPSC-SkgM (p < 0.05) from both SAM and nonSAM patients. Transcriptomic analysis revealed stronger effects on gene expression in SAM-derived iPSC-SKgM cells treated with atorvastatin (106 genes) than rosuvastatin (33 genes) compared to nonSAM cells. Enrichment analyses predicted associations of these genes with cell growth, muscle function, pro-inflammatory processes, and apoptosis. Proteomic analysis also showed more proteins differentially abundant in atorvastatin (61 proteins) than in rosuvastatin (26 proteins) treated cells. These proteins were related to cell biosynthetic process, signaling and communication, nucleic acid metabolism, and protein processing. In conclusion, atorvastatin has greater toxicity than rosuvastatin to iPSC-SKgM cells, an outcome exacerbated in FH patients who experienced SAM. Atorvastatin has stronger effects on expression of molecules involved in several signaling pathways suggesting novel molecular mechanisms of statin-induced myotoxicity.

Exploring Anti-Inflammatory Treatment as Upstream Therapy in the Management of Atrial Fibrillation

Inflammation has been widely recognized as one of the major pathophysiological drivers of the development of atrial fibrillation (AF), which works in tandem with other risk factors of AF including obesity, diabetes, hypertension, and heart failure (HF). Our current understanding of the role of inflammation in the natural history of AF remains elusive; however, several key players, including the NLRP3 (NLR family pyrin domain containing 3) inflammasome, have been acknowledged to be heavily influential on chronic inflammation in the atrial myocardium, which leads to fibrosis and eventual degradation of its electrical function. Nevertheless, our current methods of pharmacological modalities with reported immunomodulatory properties, including well-established classes of drugs e.g., drugs targeting the renin-angiotensin-aldosterone system (RAAS), statins, and vitamin D, have proven effective in reducing the overall risk of developing AF, the onset of postoperative atrial fibrillation (POAF), and reducing overall mortality among patients with AF. This might bring hope for further progress in developing new treatment modalities targeting cellular checkpoints of the NLRP3 inflammasome pathway, or revisiting other well-known anti-inflammatory drugs e.g., colchicine, vitamin C, nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticosteroids, and antimalarial drugs. In our review, we aim to find relevant upstream anti-inflammatory treatment methods for the management of AF and present the most current real-world evidence of their clinical utility.

Impact of quetiapine on ion channels and contractile dynamics in rat ventricular myocyte

Antipsychotic drugs often lead to adverse effects, including those related to the cardiovascular system. Of these, quetiapine is known to cause significant changes in the QT interval although the underlying mechanism remains mysterious, prompting us to examine its effects on cardiac electrophysiological properties. Therefore, we investigated the effect of quetiapine on contraction, action potential (AP), and the associated membrane currents such as L-type Ca2+ and K+ using the whole-cell patch clamp method to examine its impacts on isolated rat ventricular myocytes. Our results showed that (1) quetiapine reduces cell contractility in a concentration-dependent manner and (2) leads to a significant prolongation in the duration of AP in isolated ventricular myocytes. This effect was both concentration and frequency-dependent; (3) quetiapine significantly decreased the Ca2+, transient outward K+, and steady-state K+ currents. However, only high concentration of quetiapine (100 μM) could significantly change the activation and reactivation kinetics of L-type Ca2+ channels. This study demonstrates that QT extension induced by quetiapine is mainly associated with the prolongation of AP. Moreover, quetiapine caused a significant decrease in contractile force and excitability of ventricular myocytes by suppressing Ca2+ and K+ currents.

Statins and Cardiomyocyte Metabolism, Friend or Foe?

Statins inhibit HMG-CoA reductase, the rate-limiting enzyme in cholesterol synthesis, and are the cornerstone of lipid-lowering treatment. They significantly reduce cardiovascular morbidity and mortality. However, musculoskeletal symptoms are observed in 7 to 29 percent of all users. The mechanism underlying these complaints has become increasingly clear, but less is known about the effect on cardiac muscle function. Here we discuss both adverse and beneficial effects of statins on the heart. Statins exert pleiotropic protective effects in the diseased heart that are independent of their cholesterol-lowering activity, including reduction in hypertrophy, fibrosis and infarct size. Adverse effects of statins seem to be associated with altered cardiomyocyte metabolism. In this review we explore the differences in the mechanism of action and potential side effects of statins in cardiac and skeletal muscle and how they present clinically. These insights may contribute to a more personalized treatment strategy.

Ellagic Acid Prevents Ca2+ Dysregulation and Improves Functional Abnormalities of Ventricular Myocytes via Attenuation of Oxidative Stress in Pathological Cardiac Hypertrophy

The aim of this study was to investigate whether ellagic acid (EA) treatment can prevent changes in contractile function and Ca2+ regulation of cardiomyocytes in pathologic cardiac hypertrophy. Groups were assigned as Con group; an ISO group in which the rats received isoproterenol alone (5 mg/kg/day); and an ISO + EA group in which the rats received isoproterenol and EA (20 mg/kg/day) for 4 weeks. Subsequently, fractional shortening, intracellular Ca2+ signals, and L-type Ca2+ currents of isolated ventricular myocytes were recorded. Protein expression levels were also determined by the Western blotting method. The survival rate was increased, and the upregulated cardiac hypertrophy markers were significantly attenuated with the EA treatment. The fractional shortening and relaxation rate of myocytes was decreased in the ISO group, whereas EA significantly improved these changes. Ventricular myocytes of the ISO + EA rats displayed lower diastolic Ca2+ levels, higher Ca2+ transients, shorter Ca2+ decay, and higher L-type Ca2+ currents than those of ISO rats. Protein expression analyses indicated that the upregulated p-PLB and p-CaMKII expressions were restored by EA treatment, suggesting improved calcium handling in the ISO + EA rat heart. Moreover, ISO rats displayed significantly increased expression of p-22phox and p47phox subunits of NOX2 protein. Expression of the p22phox subunit was reduced with EA administration, while the decrease in p47phox did not reach a significant level. The increased ROS impairs Ca2+ homeostasis and contractile activity of cardiac myocytes, whereas chronic EA administration prevents Ca2+ dysregulation and functional abnormalities associated with pathological cardiac hypertrophy via the diminution of oxidative stress.