Zeolite structures loading with an anticancer compound as drug delivery systems

The authors are thankful to Dr. A. S. Azevedo for collecting the powder diffraction data.Two different structures of zeolites, faujasite (FAU) and Linde type A (LTA), were studied to investigate their suitability for drug delivery systems (DDS). The zeolites in the sodium form (NaY and NaA) were used as hosts for encapsulation of α-cyano-4- hydroxycinnamic acid (CHC). CHC, an experimental anticancer drug, was encapsulated in both zeolites by diffusion in liquid phase. These new drug delivery systems, CHC@zeolite, were characterized by spectroscopic techniques (FTIR, 1H NMR, 13C and 27Al solidstate MAS NMR, and UV−vis), chemical analysis, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effect of the zeolites and CHC@zeolite drug deliveries on HCT-15 human colon carcinoma cell line viability was evaluated. Both zeolites alone revealed no toxicity to HCT-15 cancer cells. Importantly, CHC@zeolite exhibit an inhibition of cell viability up to 585-fold, when compared to the non-encapsulated drug. These results indicate the potential of the zeolites for drug loading and delivery into cancer cells to induce cell deathO.M. and R.A. are recipients of fellowships (SFRH/BD/36463/2007, SFRH/BI/51118/2010) from Fundação para a Ciência e a Tecnologia (FCT, Portugal). This work was supported by the FCT projects refs PEst-C/ QUI/UI0686/2011, PEst-C/CTM/LA0011/2011, and PTDC/ SAU-FCF/104347/2008, under the scope of “Programa Operacional Temático Factores de Competitividade” (COMPETE) of “Quadro Comunitário de Apoio III” and cofinanced by Fundo Comunitário Europeu FEDER, and the Centre of Chemistry and Life and Health Sciences Research Institute (University of Minho, Portugal)

Cardiac responses to β‐adrenoceptor stimulation is partly dependent on mitochondrial calcium uniporter activity

Background and Purpose: Despite the importance of mitochondrial Ca2+ to metabolic regulation and cell physiology, little is known about the mechanisms that regulate Ca2+ entry into the mitochondria. Accordingly, we established a system to determine the role of the mitochondrial Ca2+ uniporter in an isolated heart model, at baseline and during increased workload following β-adrenoceptor stimulation. Experimental Approach: Cardiac contractility, oxygen consumption and intracellular Ca2+ transients were measured in ex vivo perfused murine hearts. Ru360 and spermine were used to modify mitochondrial Ca2+ uniporter activity. Changes in mitochondrial Ca2+ content and energetic phosphate metabolite levels were determined. Key Results: The addition of Ru360, a selective inhibitor of the mitochondrial Ca2+ uniporter, induced progressively and sustained negative inotropic effects that were dose-dependent with an EC50 of 7 μM. Treatment with spermine, a uniporter agonist, showed a positive inotropic effect that was blocked by Ru360. Inotropic stimulation with isoprenaline elevated oxygen consumption (2.7-fold), Ca2+-dependent activation of pyruvate dehydrogenase (5-fold) and mitochondrial Ca2+ content (2.5-fold). However, in Ru360-treated hearts, this parameter was attenuated. In addition, β-adrenoceptor stimulation in the presence of Ru360 did not affect intracellular Ca2+ handling, PKA or Ca2+/calmodulin-dependent PK signalling. Conclusions and Implications: Inhibition of the mitochondrial Ca2+ uniporter decreases β-adrenoceptor response, uncoupling between workload and production of energetic metabolites. Our results support the hypothesis that the coupling of workload and energy supply is partly dependent on mitochondrial Ca2+ uniporter activity.Centro de Investigaciones Cardiovasculare

Cardiac responses to β-adrenoceptor stimulation is partly dependent on mitochondrial calcium uniporter activity

Background and Purpose: Despite the importance of mitochondrial Ca2+ to metabolic regulation and cell physiology, little is known about the mechanisms that regulate Ca2+ entry into the mitochondria. Accordingly, we established a system to determine the role of the mitochondrial Ca2+ uniporter in an isolated heart model, at baseline and during increased workload following β-adrenoceptor stimulation. Experimental Approach: Cardiac contractility, oxygen consumption and intracellular Ca2+ transients were measured in ex vivo perfused murine hearts. Ru360 and spermine were used to modify mitochondrial Ca2+ uniporter activity. Changes in mitochondrial Ca2+ content and energetic phosphate metabolite levels were determined. Key Results: The addition of Ru360, a selective inhibitor of the mitochondrial Ca2+ uniporter, induced progressively and sustained negative inotropic effects that were dose-dependent with an EC50 of 7 μM. Treatment with spermine, a uniporter agonist, showed a positive inotropic effect that was blocked by Ru360. Inotropic stimulation with isoprenaline elevated oxygen consumption (2.7-fold), Ca2+-dependent activation of pyruvate dehydrogenase (5-fold) and mitochondrial Ca2+ content (2.5-fold). However, in Ru360-treated hearts, this parameter was attenuated. In addition, β-adrenoceptor stimulation in the presence of Ru360 did not affect intracellular Ca2+ handling, PKA or Ca2+/calmodulin-dependent PK signalling. Conclusions and Implications: Inhibition of the mitochondrial Ca2+ uniporter decreases β-adrenoceptor response, uncoupling between workload and production of energetic metabolites. Our results support the hypothesis that the coupling of workload and energy supply is partly dependent on mitochondrial Ca2+ uniporter activity.Fil: Fernandez Sada, E.. Tecnológico de Monterrey; MéxicoFil: Silva Platas, C.. Tecnológico de Monterrey; MéxicoFil: Villegas, C. A.. Tecnológico de Monterrey; MéxicoFil: Rivero, S. L.. Tecnológico de Monterrey; MéxicoFil: Willis, B. C.. Tecnológico de Monterrey; MéxicoFil: García, N.. Tecnológico de Monterrey; México. Instituto de Cardiología y Medicina Vascular; MéxicoFil: Garza, J. R.. Tecnológico de Monterrey; MéxicoFil: Oropeza Almazán, Y.. Tecnológico de Monterrey; MéxicoFil: Valverde, Carlos Alfredo. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico la Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Médicas; ArgentinaFil: Mazzocchi, Gabriela. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnológico la Plata. Centro de Investigaciones Cardiovasculares "Dr. Horacio Eugenio Cingolani"; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Médicas; ArgentinaFil: Zazueta, C.. Instituto Nacional de Cardiología ‘Ignacio Chávez’; MéxicoFil: Torre Amione, G.. Tecnológico de Monterrey; México. Instituto de Cardiología y Medicina Vascular; MéxicoFil: García Rivas, G.. Tecnológico de Monterrey; México. Instituto de Cardiología y Medicina Vascular; Méxic

Serum Irisin Levels, Endothelial Dysfunction, and Inflammation in Pediatric Patients with Type 2 Diabetes Mellitus and Metabolic Syndrome

The prevalence of type 2 diabetes mellitus (T2DM) and metabolic syndrome (MetS) has increased in the pediatric population. Irisin, an adipomyokine, is involved in white adipose tissue browning, energy expenditure, insulin sensitivity, and anti-inflammatory pathways. Data on the associations among circulating irisin levels, soluble cell adhesion molecules (sCAMs), and inflammatory cytokines is scarce in children and adolescents with MetS and T2DM. Subjects aged 6-16 years were grouped into T2DM, MetS, and healthy controls. Serum irisin levels were significantly lower in the MetS (6.6 [2.8-18.0] ng/mL) and T2DM (6.8 [2.2-23.2] ng/mL) groups compared with controls (30.3 [24.6-57.1] ng/mL). Negative correlations between irisin and the BMI percentile (R=−0.358), WC percentile (R=−0.308), and triglycerides (R=−0.284) were identified, while positive associations with TC (R=0.287), HDL-c (R=0.488), and LDL-c (R=0.414) were observed. Significant negative correlations were found between irisin and sNCAM (R=−0.382), sICAM-2 (R=−0.300), sVCAM-1 (R=−0.292), MCP-1 (R=−0.308), and IFN-α2 (R=−0.406). Of note, lower concentrations of most sCAMs (sICAM-1, sPSGL-1, sP-selectin, sEpCAM, sICAM-2, sALCAM, sPECAM-1, sCD44, sVCAM-1, sICAM-3, sL-selectin, and sNCAM) were shown in T2DM subjects compared with MetS patients. Lower irisin levels induce a lack of inhibition of oxidative stress and inflammation. In T2DM, higher ROS, AGEs, glucotoxicity, and inflammation trigger endothelial cell apoptosis, which downregulates the sCAM expression as a compensatory mechanism to prevent further vascular damage. In opposition, in subjects with MetS that have not yet developed T2DM and its accompanying stressors, the upregulation of the sCAM expression is ensued

Proinflammatory Cytokines Are Soluble Mediators Linked with Ventricular Arrhythmias and Contractile Dysfunction in a Rat Model of Metabolic Syndrome

Metabolic syndrome (MS) increases cardiovascular risk and is associated with cardiac dysfunction and arrhythmias, although the precise mechanisms are still under study. Chronic inflammation in MS has emerged as a possible cause of adverse cardiac events. Male Wistar rats fed with 30% sucrose in drinking water and standard chow for 25–27 weeks were compared to a control group. The MS group showed increased weight, visceral fat, blood pressure, and serum triglycerides. The most important increases in serum cytokines included IL-1β (7-fold), TNF-α (84%), IL-6 (41%), and leptin (2-fold), the latter also showing increased gene expression in heart tissue (35-fold). Heart function ex vivo in MS group showed a decreased mechanical performance response to isoproterenol challenge (ISO). Importantly, MS hearts under ISO showed nearly twofold the incidence of ventricular fibrillation. Healthy rat cardiomyocytes exposed to MS group serum displayed impaired contractile function and Ca2+ handling during ISO treatment, showing slightly decreased cell shortening and Ca2+ transient amplitude (23%), slower cytosolic calcium removal (17%), and more frequent spontaneous Ca2+ release events (7.5-fold). As spontaneous Ca2+ releases provide a substrate for ventricular arrhythmias, our study highlights the possible role of serum proinflammatory mediators in the development of arrhythmic events during MS

Amorphous SiO2 nanoparticles promote cardiac dysfunction via the opening of the mitochondrial permeability transition pore in rat heart and human cardiomyocytes

BACKGROUND: Silica nanoparticles (nanoSiO2) are promising systems that can deliver biologically active compounds to tissues such as the heart in a controllable manner. However, cardiac toxicity induced by nanoSiO2 has been recently related to abnormal calcium handling and energetic failure in cardiomyocytes. Moreover, the precise mechanisms underlying this energetic debacle remain unclear. In order to elucidate these mechanisms, this article explores the ex vivo heart function and mitochondria after exposure to nanoSiO2. RESULTS: The cumulative administration of nanoSiO2 reduced the mechanical performance index of the rat heart with a half-maximal inhibitory concentration (IC50) of 93 μg/mL, affecting the relaxation rate. In isolated mitochondria nanoSiO2 was found to be internalized, inhibiting oxidative phosphorylation and significantly reducing the mitochondrial membrane potential (ΔΨm). The mitochondrial permeability transition pore (mPTP) was also induced with an increasing dose of nanoSiO2 and partially recovered with, a potent blocker of the mPTP, Cyclosporine A (CsA). The activity of aconitase and thiol oxidation, in the adenine nucleotide translocase, were found to be reduced due to nanoSiO2 exposure, suggesting that nanoSiO2 induces the mPTP via thiol modification and ROS generation. In cardiac cells exposed to nanoSiO2, enhanced viability and reduction of H2O2 were observed after application of a specific mitochondrial antioxidant, MitoTEMPO. Concomitantly, CsA treatment in adult rat cardiac cells reduced the nanoSiO2-triggered cell death and recovered ATP production (from 32.4 to 65.4%). Additionally, we performed evaluation of the mitochondrial effect of nanoSiO2 in human cardiomyocytes. We observed a 40% inhibition of maximal oxygen consumption rate in mitochondria at 500 μg/mL. Under this condition we identified a remarkable diminution in the spare respiratory capacity. This data indicates that a reduction in the amount of extra ATP that can be produced by mitochondria during a sudden increase in energy demand. In human cardiomyocytes, increased LDH release and necrosis were found at increased doses of nanoSiO2, reaching 85 and 48%, respectively. Such deleterious effects were partially prevented by the application of CsA. Therefore, exposure to nanoSiO2 affects cardiac function via mitochondrial dysfunction through the opening of the mPTP. CONCLUSION: The aforementioned effects can be partially avoided reducing ROS or retarding the opening of the mPTP. These novel strategies which resulted in cardioprotection could be considered as potential therapies to decrease the side effects of nanoSiO2 exposure

Ex Vivo Cardiotoxicity of Antineoplastic Casiopeinas Is Mediated through Energetic Dysfunction and Triggered Mitochondrial-Dependent Apoptosis

Casiopeinas are a group of copper-based antineoplastic molecules designed as a less toxic and more therapeutic alternative to cisplatin or Doxorubicin; however, there is scarce evidence about their toxic effects on the whole heart and cardiomyocytes. Given this, rat hearts were perfused with Casiopeinas or Doxorubicin and the effects on mechanical performance, energetics, and mitochondrial function were measured. As well, the effects of Casiopeinas-triggered cell death were explored in isolated cardiomyocytes. Casiopeinas III-Ea, II-gly, and III-ia induced a progressive and sustained inhibition of heart contractile function that was dose- and time-dependent with an IC50 of 1.3 ± 0.2, 5.5 ± 0.5, and 10 ± 0.7 μM, correspondingly. Myocardial oxygen consumption was not modified at their respective IC50, although ATP levels were significantly reduced, indicating energy impairment. Isolated mitochondria from Casiopeinas-treated hearts showed a significant loss of membrane potential and reduction of mitochondrial Ca2+ retention capacity. Interestingly, Cyclosporine A inhibited Casiopeinas-induced mitochondrial Ca2+ release, which suggests the involvement of the mitochondrial permeability transition pore opening. In addition, Casiopeinas reduced the viability of cardiomyocytes and stimulated the activation of caspases 3, 7, and 9, demonstrating a cell death mitochondrial-dependent mechanism. Finally, the early perfusion of Cyclosporine A in isolated hearts decreased Casiopeinas-induced dysfunction with reduction of their toxic effect. Our results suggest that heart cardiotoxicity of Casiopeinas is similar to that of Doxorubicin, involving heart mitochondrial dysfunction, loss of membrane potential, changes in energetic metabolites, and apoptosis triggered by mitochondrial permeability