Nanomechanical Properties of Engineered Cardiomyocytes Under Electrical Stimulation

Engineered cardiomyocytes made of human-induced pluripotent stem cells (iPSC) present phenotypical characteristics similar to human fetal cardiomyocytes. There are different factors that are essential for engineered cardiomyocytes to be functional, one of them being that their mechanical properties must mimic those of adult cardiomyocytes. Techniques, such as electrical stimulation, have been used to improve the extracellular matrix's alignment and organization and improve the intracellular environment. Therefore, electrical stimulation could potentially be used to enhance the mechanical properties of engineered cardiac tissue. The goal of this study is to establish the effects of electrical stimulation on the elastic modulus of engineered cardiac tissue. Nanoindentation tests were performed on engineered cardiomyocyte constructs under seven days of electrical stimulation and engineered cardiomyocyte constructs without electrical stimulation. The tests were conducted using BioSoft™ In-Situ Indenter through displacement control mode with a 50 µm conospherical diamond fluid cell probe. The Hertzian fit model was used to analyze the data and obtain the elastic modulus for each construct. This study demonstrated that electrically stimulated cardiomyocytes (6.98 ± 0.04 kPa) present higher elastic modulus than cardiomyocytes without electrical stimulation (4.96 ± 0.29 kPa) at day 7 of maturation. These results confirm that electrical stimulation improves the maturation of cardiomyocytes. Through this study, an efficient nanoindentation method is demonstrated for engineered cardiomyocyte tissues, capable of capturing the nanomechanical differences between electrically stimulated and non-electrically stimulated cardiomyocytes.

Immunomodulatory mAbs as Tools to Investigate on Cis-Interaction of PD-1/PD-L1 on Tumor Cells and to Set Up Methods for Early Screening of Safe and Potent Combinatorial Treatments

Antibodies targeting Immune Checkpoints (IC) on tumor infiltrating lymphocytes improve immune responses against cancer. Recently, the expression of some ICs has also been reported on cancer cells. We used the clinically validated Ipilimumab and Nivolumab and other novel human antibodies targeting Cytotoxic T- lymphocyte-antigen 4 (CTLA-4), Programmed Death receptor-1 (PD-1) and Programmed Death Ligand 1 (PD-L1) to shed light on the functions of these ICs in cancer cells. We show here for the first time that all these antagonistic mAbs are able to reduce Erk phosphorylation and, unexpectedly, to induce a significant increase of ICs expression on tumor cells, involving a hyperphosphorylation of NF-kB. On the contrary, agonistic PD-L1 and PD-1 recombinant proteins showed opposite effects by leading to a significant reduction of PD-1 and PD-L1, thus also suggesting the existence of a crosstalk in tumor cells between multiple ICs. Since the immunomodulatory mAbs show their higher anti-tumor efficacy by activating lymphocytes against cancer cells, we also investigated whether it was possible to identify the most efficient combinations of immunomodulatory mAbs for achieving potent anti-tumor efficacy associated with the lowest adverse side effects by setting up novel simple and predictive in vitro models based on co-cultures of tumor cells or human fetal cardiomyocytes with lymphocytes. We demonstrate here that novel combinations of immunomodulatory mAbs with more potent anti-cancer activity than Ipilimumab and Nivolumab combination can be identified with no or lower cardiotoxic side effects. Thus, we propose these co-cultures-based assays as useful tools to test also other combinatorial treatments of emerging immunomodulatory mAbs against different ICs for the early screening of most potent and safe combinatorial therapeutic regimens.

Polydatin reduces cardiotoxicity of tyrosine kinase inhibitor sunitinib by decreasing pro-oxidative stress, pro-inflammatory cytokines and NLRP3 inflammasome expression.

e15065 Background: : Polydatin has anticancer and anti-inflammatory properties, however no studies investigated on its putative cardioprotective effects against anticancer therapies. Sunitinib, a recently-approved, multi-targeted tyrosine kinases inhibitor, prolongs survival in patients with metastatic renal cell carcinoma and gastrointestinal stromal tumors, however a dose related cardiotoxicity was well described. We investigated on the reduction of cytokines and growth factors of polydatin resulting in putative cardioprotective effects. Methods: Human fetal cardiomyocytes were untreated (control) or treated for 48 h with polydatin (50,100,200 and 400 µM) or sunitinib (5,10,25 and 50 µM) alone or combined to polydatin. After the incubation period, we performed the following tests: determination of cell viability, through analysis of mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular malondialdehyde and 4-hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro-inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of TLR4/MyD88; mTORC1 Fox01/3a; transcriptional activation of p65/NF-κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6). Results: Exposure of adult cardiomyocytes to polydatin combined to plasma-relevant concentrations of sunitinib reduces significantly intracellular reactive oxygen species, lipid peroxidation and cytochrome c release from mitochondria leading to a reduction in cell death compared to cells exposed to sunitinib alone. Polydatin reduces expression of pro-inflammatory cytokines and growth factors involved in myocardial damages and down-regulates the signaling pathway of NLRP3 inflammasome and NF-κB, increasing cellular resistance to sunitinib-mediated damages. Conclusions: Data of the present study, although in vitro, indicate that polydatin, besides reducing oxidative stress, has cardioprotective and anti-inflammatory properties, thus indicating one the mechanism(s) by which this metabolite of resveratrol might decrease sunitinib-mediated cardiotoxicity.

Cytoprotective effects of spirulina extract against doxorubicin‐induced cardiotoxicity: Biochemical evidences and translational perspectives in cardio-oncology.

e15042 Background: Spirulina, a blue-green algae used in the daily diet of natives of Africa and America, has antioxidant, anticancer, antiviral, hepatoprotective, immune enhancing and lipid-lowering effects. Considering that doxorubicin-induced cardiotoxicity involves myocardial inflammation, ferroptosis and overexpression of several cytokines involved in cell dead and apoptosis, the use of spirulina during exposure to doxorubicin could be an intriguing method to reduces myocardial injuries in cancer patients undergoing treatment with anthracyclines. Methods: Human fetal cardiomyocytes (HFC cell line) were exposed to doxorubicin (from 10 to 500 nM), alone or in combination with spirulina extract (from 10 to 100 µg/ml) for 24 and 48h. After the incubation period, we performed the following tests: determination of cell viability, through analysis of mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular Malondialdehyde and 4-hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro-inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of TLR4/MyD88; mTORC1 Fox01/3a; transcriptional activation of p65/NF-κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6). Results: Spirulina extract, co-incubated with doxorubicin exerts cardioprotective effects, enhancing cell viability of 20-36.7 % compared to untreated cells (p<0,01 for all); spirulina extract reduced significantly the cardiotoxicity through MyD88/NF-KB/cytokines axis and mTORC1 Fox01/3α mediated mechanisms and reduces oxidative damages of doxorubicin resulting in lower intracellular calcium content. Conclusions: For the first time, it was demonstrated that spirulina extract exert anti-inflammatory and cytoprotective properties in myocardial cells exposed to growing concentration of doxorubicin leading to preclinical studies in mice analyzing any effects on cardiac strain and left ventricular ejection function.

GLUCOCORTICOIDS REGULATE MITOCHONDRIAL FATTY ACID OXIDATION IN FETAL CARDIOMYOCYTES

ABSTRACTThe late gestational rise in glucocorticoids contributes to the structural and functional maturation of the perinatal heart. Here, we hypothesised that glucocorticoid action contributes to the metabolic switch in perinatal cardiomyocytes from carbohydrate to fatty acid oxidation. In primary mouse fetal cardiomyocytes, dexamethasone treatment induced expression of genes involved in fatty acid oxidation and increased mitochondrial oxidation of palmitate, dependent upon glucocorticoid receptor (GR). Dexamethasone did not, however, induce mitophagy or alter the morphology of the mitochondrial network. In neonatal mice, dexamethasone treatment induced cardiac expression of fatty acid oxidation genes in vivo. However, dexamethasone treatment of pregnant C57Bl/6 mice at embryonic day (E)13.5 or E16.5 failed to induce fatty acid oxidation genes in fetal hearts assessed 24 hours later. Instead, at E17.5, fatty acid oxidation genes were down-regulated by dexamethasone, as was GR itself. PGC-1α, required for glucocorticoid-induced maturation of primary mouse fetal cardiomyocytes in vitro, was down-regulated in vivo in fetal hearts at E17.5, 24 hours after dexamethasone administration. Similarly, following a course of antenatal corticosteroids in a sheep model of preterm birth, both GR and PGC-1α were down-regulated in fetal heart. These data suggest endogenous glucocorticoids support the perinatal switch to fatty acid oxidation in cardiomyocytes through changes in gene expression rather than gross changes in mitochondrial volume or mitochondrial turnover. Moreover, our data suggest that treatment with exogenous glucocorticoids may interfere with normal fetal heart maturation, possibly by down-regulating GR. This has implications for clinical use of antenatal corticosteroids when preterm birth is considered a possibility.

Cardioprotective effects of PCSK9 inhibitor evolocumab against doxorubicin-trastuzumab sequential treatments and ipilimumab-induced cardiotoxicity: the role of MyD88/NF-KB/mTORC1 pathways

Introduction Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as a novel therapy to treat hypercholesterolaemia and related cardiovascular diseases. Evolocumab, a PCSK9 inhibitor, reduced the risk of cardiovascular events in patients with atherosclerotic cardiovascular diseases when added to maximally tolerated statin therapy (± ezetimibe), and recent data from the ODYSSEY OUTCOMES trial indicate that alirocumab added to maximally tolerated statin therapy (± other lipid-lowering drugs) reduces the risk of cardiovascular events in patients with a recent acute coronary syndrome. Purpose Considering the expression of PCSK9 in heart tissue, we aimed to study for the first time the direct biochemical effects of evolocumab in cardiomyocytes during exposure to doxorubicin, trastuzumab, their sequential treatments, and immune checkpoint inhibitor ipilmumab. Methods Human fetal cardiomyocytes (HFC cell line) were exposed to subclinical concentration of doxorubicin, trastuzumab, sequential treatment of both ( all 100 nM), alone or in combination with evolocumab (50 nM) for 48h. In another experiment, in co-coltures of human fetal cardiomyocytes and lymphocytes, we incubated ipilimumab (200 nM) alone or in combination with evolocumab for 48h. After the incubation period, we performed the following tests: determination of cell viability, through analysis of mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular Malondialdehyde and 4-hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro-inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of TLR4/MyD88; mTORC1 Fox01/3a; transcriptional activation of p65/NF-κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6). Results Evolocumab co-incubated with doxorubicin alone or in sequence with trastuzumab exerts cardioprotective effects, enhancing cell viability of 35–43% compared to untreated cells (p&lt;0,05 for all); Cardiomyocytes co-incubated withevolocumab and ipilimumab (in co-colture of cardiomyocytes and lymphocytes) reduces significantly the cardiotoxicity phenomena through MyD88/NF-KB/cytokines axis and mTORC1 Fox01/3α mediated mechanisms. Conclusion We demonstrated, for the firts time, that PCSK9 inhibitor evolocumab exerts direct effects in cardiomyocytes during doxorubicin, trastuzumab and ipilimumab mediated cardiotoxicity turning on a new light on its possible use in the management of the cardiotoxic effects of antineoplastic drugs in cancer patients Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was funded by the “Ricerca Corrente” grant from the Italian Ministry of Health

Ozone Exerts Cytoprotective and Anti-Inflammatory Effects in Cardiomyocytes and Skin Fibroblasts after Incubation with Doxorubicin

Introduction. Skin reactions and cardiotoxicity are one of the most common side effects of doxorubicin in cancer patients. The main mechanisms based on the etiopathogenesis of these reactions are mediated by the overproduction of proinflammatory cytokines, metalloproteases, and the disruption of mitochondrial homeostasis. Ozone therapy demonstrated anti-inflammatory effects in several preclinical and clinical studies. The aim of this research is based on the evaluation of cardioprotective and dermatoprotective effects of ozone during incubation with doxorubicin, giving preliminary evidences for further studies in the field of cardio-oncology. Methods. Human skin fibroblast cells and human fetal cardiomyocytes were exposed to doxorubicin at subclinical concentration (100 nM) alone or combined with ozone concentrated from 10 up to 50 μg/mL. Cell viability and multiple anti-inflammatory studies were performed in both cell lines, with particular attention on the quantification of interleukins, leukotriene B4, NF-κB, and Nrf2 expressions during treatments. Results. Ozone decreased significantly the cytotoxicity of doxorubicin in skin fibroblasts and cardiomyocytes after 24 h of incubation. The best cytoprotective effect of ozone was reached to 30 μg/mL with a plateau phase at higher concentration. Ozone also demonstrated anti-inflammatory effects decreasing significantly the interleukins and proinflammatory mediators in both cells. Conclusion. Ozone exerts cardioprotective and dermatoprotective effects during incubation with doxorubicin, and the involved mechanisms are mediated by its anti-inflammatory effects. The overall picture described herein is a pilot study for preclinical studies in oncology.