Search Results (2,286)

Icariin (ICA) is a bioactive flavonoid compound extracted from Epimedium plants. In recent years, it has attracted significant research interest in the field of bone tissue repair due to its pharmacological effects via multiple targets and pathways. Studies have shown that ICA promotes the osteogenic differentiation of mesenchymal stem cells (MSCs) and enhances bone matrix formation by regulating signaling pathways such as Akt and Wnt/β-catenin. It concurrently inhibits osteoclast activity to maintain the balance of bone remodeling, thereby simultaneously stimulating new bone regeneration and suppressing bone resorption. At the same time, ICA exerts potent anti-inflammatory and antioxidant effects and promotes angiogenesis, improving the local microenvironment of bone injury and significantly facilitating the regeneration of bone and cartilage tissues. Additionally, ICA exhibits notable protective effects in multiple organ systems including the cardiovascular, hepatic, renal, and nervous systems. Specifically, ICA reduces cardiomyocyte apoptosis and fibrosis to preserve cardiac function, improves hepatic metabolic function and alleviates oxidative stress, attenuates renal inflammation and fibrosis, and—through neuroprotective actions—reduces neuroinflammation and promotes neuronal survival. These multi-organ effects help optimize the systemic environment for bone healing. However, ICA faces significant pharmacokinetic challenges. It has low oral bioavailability (due to poor absorption and extensive first-pass metabolism) as well as a short half-life. Consequently, maintaining effective drug concentrations in vivo is difficult, which limits its therapeutic efficacy and impedes clinical translation. To fully realize its regenerative potential, advanced drug delivery strategies (e.g., nanocarrier-based delivery systems) are being explored to enhance ICA’s bioavailability and prolong its duration of action. Overall, ICA’s multi-modal actions on bone cells, the immune microenvironment, and systemic factors make it a promising multi-target agent for bone regeneration. Addressing its pharmacokinetic limitations through optimized delivery and conducting further clinical studies will be crucial to realize its full therapeutic potential. This review provides a comprehensive overview of recent advances and challenges in translating ICA’s benefits into orthopedic therapy. Full article

Doxorubicin (Dox) is a potent anthracycline antitumor drug whose clinical utility is significantly restricted by its dose-dependent, cumulative cardiotoxicity, driven by increased oxidative stress, impaired antioxidant defenses, and apoptosis-mediated cardiomyocyte loss. Methylene blue (MB), a phenothiazine derivative with well-documented redox-modulating properties, is being explored as a viable cardioprotective agent due to its antioxidant and anti-apoptotic effects. This study evaluated the protective role of MB against Dox-induced cardiotoxicity in rats by examining its impact on oxidative stress markers (Kelch-like ECH-associated protein 1; KEAP1, nuclear factor erythroid 2-related factor 2; NRF2, Glutathione peroxidase 4; GPX-4, 8-hydroxy-2′-deoxyguanosine; 8-OHdG), neurohormonal indicators (noradrenaline), cardiac injury biomarkers (troponin I), and apoptotic mediators (p53, Caspase-3). Forty male albino rats were divided equally into four groups: control, Dox (15 mg/kg, i.p.), MB alone (4 mg/kg/day, p.o. for 7 days), and Dox plus MB. Dox administration significantly increased serum troponin I and noradrenaline levels, elevated cardiac KEAP1 and 8-OHdG, and reduced NFE2L2, NRF2, and GPX-4 expression. It also upregulated p53 and Caspase-3 and caused marked myocardial degeneration, necrosis, and inflammatory infiltration. MB co-treatment significantly reduced troponin I and noradrenaline levels, restored KEAP1/NFE2L2 (NRF2)/GPX-4 pathway balance, decreased oxidative DNA damage, and attenuated p53 and Caspase-3 activation, preserving myocardial architecture with minimal inflammatory changes. These findings demonstrate that MB confers potent cardioprotection against Dox-induced cardiac injury by enhancing antioxidant defenses, limiting oxidative DNA damage, suppressing apoptosis, and normalizing neurohormonal imbalance, suggesting its promise as an adjunctive strategy to mitigate anthracycline-associated cardiotoxicity. Full article

Human embryonic stem cell-derived cardiomyocytes (hESC-CMs) tend to show a mixed population of action potential (AP) types, including atrial-like (A-like) and ventricular-like (V-like) APs. In the present study, we investigated the membrane currents underlying these two AP types in hESC-CMs. These were generated using standard (Std) and retinoic acid (RA)-based differentiation protocols. Patch clamp methodology was used to correlate AP morphology with major cardiac ion currents by applying alternating current and voltage clamp protocols to each cell, and to measure L-type Ca²⁺ current (I_Ca,L) and Na⁺-Ca²⁺ exchange current (I_NCX) in detail, whereas Ca²⁺ transients were measured ratiometrically using Indo-1. A- and V-like APs were found in both Std and RA-treated hESC-CMs and the AP plateau amplitude (AP_plat), as a measure of fast phase-1 repolarization, appeared the best AP criterion to separate these two AP types. Traditional voltage clamp experiments revealed a significantly smaller I_Ca,L density in RA-treated hESC-CMs, as well as larger densities of the transient outward and delayed rectifier K⁺ currents (I_to1 and I_K, respectively), without changes in the inward rectifier K⁺ current (I_K1). The AP_plat showed strong and moderate correlations with the densities of I_Ca,L and I_K, respectively, in the absence of a clear-cut correlation with the density of I_to1. Using pre-recorded, typical A- and V-like APs, AP clamp demonstrated that the I_Ca,L-mediated Ca²⁺ influx during the V-like AP in Std hESC-CMs is 3.15 times larger than the influx during the A-like AP in RA-treated hESC-CMs. Ca²⁺ transients of A-like hESC-CMs have a lower diastolic and systolic level, as well as a lower amplitude, than those of Std hESC-CMs, while their duration is shorter due to enhanced SERCA activity. In conclusion, I_Ca,L is an important determinant of the differently shaped A- and V-like APs in hESC-CMs. Furthermore, the Ca²⁺ homeostasis differs between A- and V-like hESC-CMs due to the smaller I_Ca,L and enhanced SERCA activity during A-like APs, resulting in a strongly reduced Ca²⁺ influx, which will cause a substantial reduction in I_NCX, further contributing to the shorter A-like APs. Full article

Sepsis-induced myocardial injury is age-related and leads to increased mortality. Considering the importance of mitochondrial dysfunction in cardiac impairment, we aimed to investigate whether aging exacerbates the cardiac mitochondrial metabolic response to inflammation, thus leading to increased cardiac dysfunction in the elderly. Cecal ligation and puncture (CLP) was conducted in young adult (12–18 weeks) and aged (19–21 months) male C57BL/6 mice. Cardiac function was detected 20 h post-CLP. Additionally, cardiomyocytes isolated from young adult and aged male mice were used for assessments of mitochondrial respiratory function +/– TNFα or LPS. Protein levels of oxidative phosphorylation (OXPHOS), NADPH oxidase (NOX)2, NOX4, phosphor-STAT3 and STAT3 were determined in mouse hearts 24 h post-CLP and in cardiomyocytes following inflammatory stimuli. CLP significantly reduced cardiac contractility in both young and aged mice, with a higher incidence and greater severity of cardiac functional depression in the older group. Mitochondrial respiratory capacity was decreased in cardiomyocytes derived from aged mice, with increased susceptible to inflammatory toxic effects compared to those from young adult mice. The age-dependent changes were observed in myocardial OXPHOS complexes and NOX4. Importantly, CLP led to a significant increase in OXPHOS protein levels in the hearts of older mice, suggesting a possible compensatory response to decreased mitochondrial metabolic function and a greater potential for reactive oxygen species (ROS) generation. Our findings highlight that the response of aging-impaired mitochondria to inflammation may underlie the worsened cardiac functional depression in the aged group during sepsis. Full article

Cardiomyocyte hypertrophy is regulated by several factors, including the ADP-ribosylation factor (Arf) family of small G proteins, among others. For instance, ArfGAP with dual pleckstrin homology domains 1 (Adap1) exerts an anti-hypertrophic effect in cultured cardiomyocytes. Its homologous protein, Adap2, is also expressed in the heart but its role remains elusive. To elucidate its function, we investigated the effects of adenoviral-mediated overexpression of Adap2 in cultured neonatal rat ventricular myocytes under both basal and pro-hypertrophic conditions, employing a range of microscopy and biochemical techniques. Despite minimal detection in neonatal rat hearts, Adap2 was found to be well expressed in adult rat hearts, being predominantly localized at the membrane fraction. In contrast to Adap1, overexpression of Adap2 provokes the robust accumulation of β1-integrin at the cellular surface of cultured cardiomyocytes. Interestingly, overexpressed Adap2 relocalizes at the sarcolemma and increases the size of cardiomyocytes upon phenylephrine stimulation, despite attenuating Erk1/2 phosphorylation and Nppa gene expression. Under these same conditions, cardiomyocytes overexpressing Adap2 also express higher level of detyrosinated tubulin, a marker of hypertrophic response. These findings provide new insights into the pro-hypertrophic function of Adap2 in cardiomyocytes. Full article

L-type Ca²⁺ channels, particularly Ca_V1.2, play a crucial role in cardiac excitation-contraction coupling and are known to exhibit mechanosensitivity. However, the mechanisms regulating their response to mechanical stress remain poorly understood. To investigate the mechanosensitivity and nitric oxide (NO)-dependent regulation of L-type Ca²⁺ channels in rat ventricular cardiomyocytes, we used RNA sequencing to assess isoform expression and whole-cell patch-clamp recordings to measure L-type Ca²⁺ current (I_Ca,L) under controlled mechanical and pharmacological conditions. RNA sequencing revealed predominant expression of Ca_V1.2 (TPM: 0.1170 ± 0.0075) compared to Ca_V1.3 (0.0021 ± 0.0002) and Ca_V1.1 (0.0002 ± 0.0002). Local axial stretch (6–10 μm) consistently reduced I_Ca,L in proportion to stretch magnitude. The NO donor SNAP (200 μM) had variable effects on basal I_Ca,L in unstretched cells (stimulatory, inhibitory, or biphasic) but consistently restored stretch-reduced I_Ca,L to control levels. Ascorbic acid (10 μM), which reduces S-nitrosylation, increased basal I_Ca,L and partially restored the reduction caused by stretch, implicating S-nitrosylation in channel regulation. The sGC inhibitor ODQ (5 μM) decreased I_Ca,L in both stretched and unstretched cells, indicating involvement of the NO–cGMP pathway. Mechanical stress modulates L-type Ca²⁺ channels through a complex interplay between S-nitrosylation and NO–cGMP signaling, with S-nitrosylation playing a predominant role in stretch-induced effects. This mechanism may represent a key component of cardiac mechanotransduction and could be relevant for therapeutic targeting in cardiac pathologies involving mechanically induced dysfunction. Full article

Hibiscus syriacus L. (HS), native to Eastern and Southern Asia, has been traditionally used in Asian herbal medicine for its anticancer, antimicrobial, and anti-inflammatory properties. Despite these recognized bioactivities, its potential cardioprotective effects, particularly in the setting of heart failure (HF), remain largely unexplored. This study aimed to investigate the effects of HS extracts and its bioactive constituents on angiotensin II (Ang II)-induced cardiac injury using an in vitro model with H9c2 rat cardiomyocytes. Cells exposed to Ang II were pretreated with HS extracts, and assays were performed to assess cell viability, reactive oxygen species (ROS) generation, protein synthesis, and secretion of inflammatory mediators, including tumor necrosis factor-alpha, interleukin 1β (IL-1β), and interleukin 6 (IL-6), as well as chemokine (CCL20) and HF-related biomarkers, such as brain natriuretic peptide (BNP) and endothelin-1. The results demonstrated that HS extracts significantly and dose-dependently attenuated Ang II-induced ROS accumulation and suppressed the secretion of pro-inflammatory cytokines, chemokines, BNP, and endothelin-1. Additionally, HS and its purified components inhibited Ang II-induced protein synthesis, indicating anti-hypertrophic effects. Collectively, these findings highlight the antioxidative, anti-inflammatory, and antihypertrophic properties of HS in the context of Ang II-induced cardiac injury, suggesting that HS may represent a promising adjunctive therapeutic candidate for HF management. Further in vivo studies and mechanistic investigations are warranted to validate its clinical potential. Full article

Mitochondria play a crucial role in adapting to fluctuating energy demands, particularly in various heart diseases. In addition to functional analyses such as the measurement of ROS or ATP, analysis of mitochondrial ultrastructure can be used to draw further conclusions about their functions and effects in tissue. In this protocol, we introduce a set of measurements to compare the ultrastructural and functional characteristics of human left ventricular mitochondria, using transmission electron microscopy (TEM). Measured parameters included mean size in µm², elongation, count, percental mitochondrial area in the measuring frame, and a conglomeration score. We also introduce a novel method of defining hydropic mitochondria as a comparable evaluation standard. With this cluster of measurement parameters, we aim to contribute a protocol for studying human mitochondrial morphology, distribution, and functionality. Full article

Diabetes mellitus, both type 1 (T1D) and type 2 (T2D), has become the epidemic of the century and a major public health concern given its rising prevalence and the increasing adoption of a sedentary lifestyle globally. This multifaceted disease is characterized by impaired pancreatic beta cell function and insulin resistance (IR) in peripheral organs, namely the liver, skeletal muscle, and adipose tissue. Additional insulin target tissues, including cardiomyocytes and neuronal cells, are also affected. The advent of stem cell research has opened new avenues for tackling this disease, particularly through the regeneration of insulin target cells and the establishment of disease models for further investigation. Human-induced pluripotent stem cells (iPSCs) have emerged as a valuable resource for generating specialized cell types, such as hepatocytes, myocytes, adipocytes, cardiomyocytes, and neuronal cells, with diverse applications ranging from drug screening to disease modeling and, importantly, treating IR in T2D. This review aims to elucidate the significant applications of iPSC-derived insulin target cells in studying the pathogenesis of insulin resistance and T2D. Furthermore, recent differentiation strategies, protocols, signaling pathways, growth factors, and advancements in this field of therapeutic research for each specific iPSC-derived cell type are discussed. Full article

Background: Induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) hold transformative potential for cardiovascular regenerative medicine, yet their clinical application is hindered by suboptimal mitochondrial maturation and metabolic inefficiencies. This systematic review evaluates targeted strategies for optimizing mitochondrial function, integrating metabolic preconditioning, substrate selection, and pathway modulation to enhance energy production and cellular resilience. Additionally, we examine the role of extracellular matrix stiffness and mechanical stimulation in mitochondrial adaptation, given their influence on metabolism and maturation. Methods: A comprehensive analysis of recent advancements in iPSC-CM maturation was conducted, focusing on metabolic interventions that enhance mitochondrial structure and function. Studies employing metabolic preconditioning, lipid and amino acid supplementation, and modulation of key signaling pathways, including PGC-1α, AMPK, and mTOR, were reviewed. Computational modeling approaches predicting optimal metabolic shifts were assessed, alongside insights into reactive oxygen species (ROS) signaling, calcium handling, and the impact of electrical pacing on energy metabolism. Results: Evidence indicates that metabolic preconditioning with fatty acids and oxidative phosphorylation enhancers improves mitochondrial architecture, cristae density, and ATP production. Substrate manipulation fosters a shift toward adult-like metabolism, while pathway modulation refines mitochondrial biogenesis. Computational models enhance precision, predicting interventions that best align iPSC-CM metabolism with native cardiomyocytes. The synergy between metabolic and biomechanical cues offers new avenues for accelerating maturation, bridging the gap between in vitro models and functional cardiac tissues. Conclusions: Strategic metabolic optimization is essential for overcoming mitochondrial immaturity in iPSC-CMs. By integrating biochemical engineering, predictive modeling, and biomechanical conditioning, a robust framework emerges for advancing iPSC-CM applications in regenerative therapy and disease modeling. These findings pave the way for more physiologically relevant cell models, addressing key translational challenges in cardiovascular medicine. Full article

Cardiac arrhythmias remain a major source of morbidity and mortality, often stemming from molecular and structural abnormalities that are insufficiently addressed by current pharmacologic and interventional therapies. Gene therapy has emerged as a transformative approach, offering precise and durable interventions that directly target the arrhythmogenic substrate. Across the spectrum of inherited and acquired arrhythmias—including long QT syndrome, Brugada syndrome, catecholaminergic polymorphic ventricular tachycardia, atrial fibrillation, and post-infarction ventricular tachycardia—gene-based strategies such as allele-specific silencing, gene replacement, CRISPR-mediated editing, and suppression-and-replacement constructs are showing growing translational potential. Advances in delivery platforms, including cardiotropic viral vectors, lipid nanoparticle-encapsulated mRNA, and non-viral reprogramming tools, have further enhanced the specificity and safety of these approaches. Additionally, innovative applications such as biological pacemaker development and mutation-agnostic therapies underscore the versatility of genetic modulation. Nonetheless, significant challenges remain, including vector tropism, immune responses, payload limitations, and the translational gap between preclinical models and human electrophysiology. Integration of patient-derived cardiomyocytes, computational simulations, and large-animal studies is expected to accelerate clinical translation. This review provides a comprehensive synthesis of the mechanistic rationale, therapeutic strategies, delivery platforms, and translational frontiers of gene therapy for cardiac arrhythmias. Full article

Doxorubicin-induced cardiotoxicity (DIC) significantly constrains the clinical efficacy of anthracycline chemotherapy, primarily through the induction of ferroptosis, an iron-dependent, regulated cell death driven by oxidative stress and lipid peroxidation. However, the upstream regulators of ferroptosis in DIC remain incompletely defined. Cold-inducible RNA-binding protein (CIRBP) exhibits cardioprotective effects in various pathological contexts, but its precise role in ferroptosis-related cardiotoxicity is unknown. This study investigated whether CIRBP mitigates DIC by modulating the ferroptosis pathway via the SLC7A11 (Solute carrier family 7 member 11)/GPX4 (Glutathione peroxidase 4) axis. We observed marked downregulation of CIRBP in cardiac tissues and cardiomyocytes following doxorubicin exposure. CIRBP knockout significantly exacerbated cardiac dysfunction, mitochondrial damage, oxidative stress, and lipid peroxidation, accompanied by increased mortality rates. Conversely, CIRBP overexpression alleviated these pathological changes. Molecular docking and dynamics simulations, supported by transcriptomic analyses, revealed direct binding of CIRBP to the 3′-UTR of Slc7a11 mRNA, enhancing its stability and promoting translation. Correspondingly, CIRBP deficiency markedly suppressed SLC7A11 and GPX4 expression, impairing cystine uptake, glutathione synthesis, and antioxidant defenses, thus amplifying ferroptosis. These ferroptotic alterations were partially reversed by ferroptosis inhibitor ferrostatin-1 (Fer-1). Collectively, this study identifies CIRBP as a critical regulator of ferroptosis in DIC, elucidating a novel post-transcriptional mechanism involving Slc7a11 mRNA stabilization. These findings offer new insights into ferroptosis regulation and highlight CIRBP as a potential therapeutic target for preventing anthracycline-associated cardiac injury. Full article

Human induced pluripotent stem cells (hiPSCs) are widely used in basic research because of their versatility and ability to differentiate into multiple cell types. In particular, differentiating hiPSCs into cardiac cells (hiPSC-CMs) has been an important milestone in cardiac pathophysiology studies. Although hiPSC-CMs offer a model for human cardiomyocytes, they still exhibit characteristics linked to the fetal cardiac cell phenotype. One important feature that prevents hiPSC-CMs from being identified as adult cells relates to their metabolism, which is a key factor in defining a mature phenotype capable of sustaining the workload requirements characteristic of fully differentiated cardiomyocytes. This review aims to present the most relevant strategies in terms of culture medium composition, culture times, and 3D culture methods that have been developed to promote the metabolic maturation of hiPSC-CMs, which are now widely used. Defining a standardized and universally accepted protocol would enable the creation of a cellular model for studies of cardiac pathophysiology from a patient-specific perspective and for drug screening. Full article

Background/Objectives: Doxorubicin is a chemotherapeutic agent whose clinical use is limited by side effects (SEs). The most common SE is doxorubicin-induced cardiotoxicity (DIC), for which there is still no prevention. The hypothesis arises that active substances of natural origin could influence DIC prevention by affecting several pathways of DIC occurrence. Methods: Thirty Wistar rats were divided into six groups (control, NADES (C8:C10) solvent, pumpkin pulp extract, doxorubicin, NADES (C8:C10) solvent–doxorubicin, and pumpkin pulp extract–doxorubicin). During the experiment, parameters of general condition, body, and heart weight were observed. Heart function parameters were monitored by measuring the levels of serum NT-pro-BNP, CK-MB, and hsTnT. Tissue damage was evaluated by determining the doxorubicin damage score and the expression of anti-cardiac troponin I, anti-Nrf2, anti-Bcl-2, anti-caspase-3, anti-COX2, and anti-Ki67 antibodies. Results: Doxorubicin administration led to impaired general condition of animals and increased the levels of NT-proBNP, CK-MB, hsTnT, and myocardium tissue damage of medium grade. Its administration induced apoptosis (as evidenced by elevated Casp3), reduced antiapoptotic Bcl-2 and troponin I expression in cardiomyocytes. Reduced Nrf2 expression due to doxorubicin administration was restored when pumpkin pulp extract containing carotenoids was coadministered, which led to the normalization of Casp3, Bcl-2, and troponin I expression. Consequently, the general condition and body weight were better in animals treated with both doxorubicin and the other treatment compared to those treated with doxorubicin alone. Conclusions: The results of this study strongly suggest that pumpkin pulp extract containing carotenoids has a cardioprotective effect, possibly by regulating the Nrf2 pathway. Full article

New approach methodologies (NAMs), including microphysiological systems (MPSs), can recapitulate structural and functional complexities of organs. Vanoxerine was reported to induce cardiac adverse events, including torsade de points (TdP), in a Phase III clinical trial. Despite earlier nonclinical animal models and Phase I–II clinical trials, events of QT prolongation or proarrhythmia were not observed. Here, we utilized cardiac NAMs to evaluate the functional consequences of vanoxerine treatment on human cardiac excitation–contraction coupling. The cardiac MPS used in this study was a microfabricated fluidic culture platform with human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) capable of evaluating voltage, intracellular calcium handling, and contractility. Likewise, the hiPSC-CM comprehensive in vitro proarrhythmia assay (CiPA) was employed based on multielectrode array (MEA). Vanoxerine treatment delayed repolarization in a concentration-dependent manner and induced proarrhythmic events in both NAM platforms. The complex cardiac MPS displayed a frequency-dependent vanoxerine response such that EADs were eliminated at a faster pacing rate (1.5 Hz). Moreover, exposure analysis revealed a 99% vanoxerine loss in the cardiac MPS. TdP risk analysis demonstrated high to intermediate TdP risk at clinically relevant concentrations of vanoxerine and frequency-independent EAD events in the hiPSC-CM CiPA model. These findings demonstrate that nonclinical cardiac NAMs can recapitulate clinical outcomes, including detection of vanoxerine-induced delayed repolarization and proarrhythmic effects. Moreover, this work provides a foundation to evaluate the safety and efficacy of novel compounds to reduce the dependence on animal studies. Full article