Role of proprotein convertase subtilisin/kexin type 9 (PCSK9) in diabetic complications.

Cardiovascular disease (CVD) complications have remained a major cause of death among patients with diabetes. Hence, there is a need for effective therapeutics against diabetes-induced CVD complications. Since its discovery, proprotein convertase subtilisin/kexin type 9 (PCSK9) has been reported to be involved in the pathology of various CVDs, with studies showing a positive association between plasma levels of PCSK9, hyperglycemia, and dyslipidemia. PCSK9 regulates lipid homeostasis by interacting with low-density lipoprotein receptors (LDLRs) present in hepatocytes and subsequently induces LDLR degradation via receptor-mediated endocytosis, thereby reducing LDL uptake from circulation. In addition, PCSK9 also induces pro-inflammatory cytokine expression and apoptotic cell death in diabetic-CVD. Furthermore, therapies designed to inhibit PCSK9 effectively reduces diabetic dyslipidemia with clinical studies reporting reduced cardiovascular events in patients with diabetes and no significant adverse effect on glycemic controls. In this review, we discuss the role of PCSK9 in the pathogenesis of diabetes-induced CVD and the potential mechanisms by which PCSK9 inhibition reduces cardiovascular events in diabetic patients.

Vitamin C: historical perspectives and heart failure.

Vitamin C (Vit C) is an ideal antioxidant as it is easily available, water soluble, very potent, least toxic, regenerates other antioxidants particularly Vit E, and acts as a cofactor for different enzymes. It has received much attention due to its ability in limiting reactive oxygen species, oxidative stress, and nitrosative stress, as well as it helps to maintain some of the normal metabolic functions of the cell. However, over 140 clinical trials using Vit C in different pathological conditions such as myocardial infarction, gastritis, diabetes, hypertension, stroke, and cancer have yielded inconsistent results. Such a divergence calls for new strategies to establish practical significance of Vit C in heart failure or even in its prevention. For a better understanding of Vit C functioning, it is important to revisit its transport across the cell membrane and subcellular interactions. In this review, we have highlighted some historical details of Vit C and its transporters in the heart with a particular focus on heart failure in cancer chemotherapy.

The Cardioprotective Role of Flaxseed in the Prevention of Doxorubicin- and Trastuzumab-Mediated Cardiotoxicity in C57BL/6 Mice.

BACKGROUND: Although the combination of doxorubicin (DOX) and trastuzumab (TRZ) reduces the progression and recurrence of breast cancer, these anticancer drugs are associated with significant cardiotoxic side effects. OBJECTIVE: We investigated whether prophylactic administration of flaxseed (FLX) and its bioactive components, α-linolenic acid (ALA) and secoisolariciresinol diglucoside (SDG), would be cardioprotective against DOX + TRZ-mediated cardiotoxicity in a chronic in vivo female murine model. METHODS: Wild-type C57BL/6 female mice (10-12 wk old) received daily prophylactic treatment with one of the following diets: 1) regular control (RC) semi-purified diet; 2) 10% FLX diet; 3) 4.4% ALA diet; or 4) 0.44% SDG diet for a total of 6 wks. Within each arm, mice received 3 weekly injections of 0.9% saline or a combination of DOX [8 mg/(kg.wk)] and TRZ [3 mg/(kg.wk)] starting at the end of week 3. The main outcome was to evaluate the effects of FLX, ALA, and SDG on cardiovascular remodeling and markers of apoptosis, inflammation, and mitochondrial dysfunction. Significance between measurements was determined using a 4 (diet) × 2 (chemotherapy) × 2 (time) mixed factorial design with repeated measures. RESULTS: In the RC + DOX + TRZ-treated mice at week 6 of the study, the left ventricular ejection fraction (LVEF) decreased by 50% compared with the baseline LVEF (P < 0.05). However, the prophylactic administration of the FLX, ALA, or SDG diet was partially cardioprotective, with mice in these treatment groups showing an ∼68% increase in LVEF compared with the RC + DOX + TRZ-treated group at week 6 (P < 0.05). Although markers of inflammation (nuclear transcription factor κB), apoptosis [poly (ADP-ribose) polymerase-1 and the ratio of BCL2-associated X protein to B-cell lymphoma-extra large], and mitochondrial dysfunction (BCL2-interacting protein 3) were significantly elevated by approximately 2-fold following treatment with RC + DOX + TRZ compared with treatment with RC + saline at week 6, prophylactic administration of FLX, ALA, or SDG partially downregulated these signaling pathways. CONCLUSION: In a chronic in vivo female C57BL/6 mouse model of DOX + TRZ-mediated cardiotoxicity, FLX, ALA, and SDG were partially cardioprotective.

Innate immune response in the pathogenesis of heart failure in survivors of myocardial infarction.

Among the different cardiovascular disease complications, atherosclerosis-induced myocardial infarction (MI) is the major contributor of heart failure (HF) and loss of life. This review presents short- and long-term features of post-MI in human hearts and animal models. It is known that the heart does not regenerate, and thus loss of cardiac cells after an MI event is permanent. In survivors of a heart attack, multiple neurohumoral adjustments as well as simultaneous remodeling in both infarcted and noninfarcted regions of the heart help sustain pump function post-MI. In the early phase, migration of inflammatory cells to the infarcted area helps repair and remove the cell debris, while apoptosis results in the elimination of damaged cardiomyocytes, and there is an increase in the antioxidant response to protect the survived myocardium against oxidative stress (OS) injury. However, in the late phase, it appears that there is a relative increase in OS and activation of the innate inflammatory response in cardiomyocytes without any obvious inflammatory cells. In this late stage in survivors of MI, a progressive slow activation of these processes leads to apoptosis, fibrosis, cardiac dysfunction, and HF. Thus, this second phase of an increase in OS, innate inflammatory response, and apoptosis results in wall thinning, dilatation, and consequently HF. It is important to note that this inflammatory response appears to be innate to cardiomyocytes. Blunting of this innate immune cardiomyocyte response may offer new hope for the management of HF.

Role of renin-angiotensin system antagonists in the prevention of bevacizumab- and sunitinib-mediated cardiac dysfunction.

Although anticancer systemic therapy agents clearly lead to improved survival in patients with cancer, these can come at the cost of serious complications including cardiotoxicity. Two types of targeted systemic therapies currently in use for colorectal cancer (CRC) and renal cell cancer (RCC), respectively, include the vascular endothelial growth factor inhibitor bevacizumab (BVZ) and the tyrosine kinase inhibitor sunitinib (SNT). Despite the beneficial effects of BVZ and SNT in improving clinical outcomes in the settings of CRC and RCC, there is an increased risk of cardiac dysfunction. The aim of the present study was to determine whether prophylactic administration of renin-angiotensin system (RAS) inhibitors would attenuate the cardiotoxic side effects of BVZ or SNT in a chronic in vivo murine model. A total of 194 wild-type C57Bl/6 male mice received: 1) 0.9% saline, 2) BVZ (10 mg·kg-1·wk-1), or 3) SNT (40 mg·kg-1·day-1) for 4 wk. Within each arm, mice received daily prophylactic treatment with hydralazine (0.05 mg/ml), aliskiren (50 mg/kg), perindopril (4 mg/kg), or valsartan (2 mg/kg). Although hydralazine effectively lowered blood pressure in BVZ- or SNT-treated mice, it did not prevent left ventricular systolic dysfunction. Prophylactic administration of aliskiren, perindopril, or valsartan prevented adverse cardiovascular remodeling in mice treated with either BVZ or SNT. The addition of RAS antagonists also downregulated expression of phosphorylated p38 and Bcl-2-like 19-kDa interacting protein 3 in SNT-treated mice. In our chronic in vivo murine model, RAS antagonists partially attenuated the development of BVZ- or SNT-mediated cardiac dysfunction. Future clinical studies are warranted to investigate the cardioprotective effects of prophylactic treatment with RAS inhibitors in the settings of CRC and RCC. NEW & NOTEWORTHY In the evolving field of cardio-oncology, bevacizumab and sunitinib improve clinical outcomes in the settings of metastatic colorectal cancer and renal cell cancer, respectively. These anticancer drugs, however, are associated with an increased risk of cardiotoxicity. The prophylactic administration of renin-angiotensin system antagonists is partially cardioprotective against bevacizumab- and sunitinib-mediated cardiac dysfunction.

Blueberry extract attenuates doxorubicin-induced damage in H9c2 cardiac cells 1.

The objective of this study was to analyze the cardioprotective roles of 3 wild blueberry genotypes and one commercial blueberry genotype by measuring markers of oxidative stress and cell death in H9c2 cardiac cells exposed to doxorubicin. Ripe berries of the 3 wild blueberry genotypes were collected from a 10-year-old clearcut forest near Nipigon, Ontario, Canada (49°1'39″N, 87°52'21″W), whereas the commercial blueberries were purchased from a local grocery store. H9c2 cardiac cells were incubated with 15 µg gallic acid equivalent/mL blueberry extract for 4 h followed by 5 µM doxorubicin for 4 h, and oxidative stress and active caspase 3/7 were analyzed. The surface area as well as total phenolic content was significantly higher in all 3 wild blueberry genotypes compared with the commercial species. Increase in oxidative stress due to doxorubicin exposure was attenuated by pre-treatment with all 3 types of wild blueberries but not by commercial berries. Furthermore, increase in caspase 3/7 activity was also attenuated by all 3 wild genotypes as well. These data demonstrate that wild blueberry extracts can attenuate doxorubicin-induced damage to H9c2 cardiomyocytes through reduction in oxidative stress and apoptosis, whereas the commercial blueberry had little effect.

Molecular hydrogen: potential in mitigating oxidative-stress-induced radiation injury 1.

Uncontrolled production of oxygen and nitrogen radicals results in oxidative and nitrosative stresses that impair cellular functions and have been regarded as causative common denominators of many pathological processes. In this review, we report on the beneficial effects of molecular hydrogen in scavenging radicals in an artificial system of •OH formation. As a proof of principle, we also demonstrate that in rat hearts in vivo, administration of molecular hydrogen led to a significant increase in superoxide dismutase as well as pAKT, a cell survival signaling molecule. Irradiation of the rats caused a significant increase in lipid peroxidation, which was mitigated by pre-treatment of the animals with molecular hydrogen. The nuclear factor erythroid 2-related factor 2 is regarded as an important regulator of oxyradical homeostasis, as well as it supports the functional integrity of cells, particularly under conditions of oxidative stress. We suggest that the beneficial effects of molecular hydrogen may be through the activation of nuclear factor erythroid 2-related factor 2 pathway that promotes innate antioxidants and reduction of apoptosis, as well as inflammation.

Doxorubicin-induced nitrosative stress is mitigated by vitamin C via the modulation of nitric oxide synthases.

An increase in oxidative stress is suggested to be the main cause in Doxorubicin (Dox)-induced cardiotoxicity. However, there is now evidence that activation of inducible nitric oxide synthase (iNOS) and nitrosative stress are also involved. The role of vitamin C (Vit C) in the regulation of nitric oxide synthase (NOS) and reduction of nitrosative stress in Dox-induced cardiotoxicity is unknown. The present study investigated the effects of Vit C in the mitigation of Dox-induced changes in the levels of nitric oxide (NO), NOS activity, protein expression of NOS isoforms, and nitrosative stress as well as cytokines TNF-α and IL-10 in isolated cardiomyocytes. Cardiomyocytes isolated from adult Sprague-Dawley rats were segregated into four groups: 1) control, 2) Vit C (25 µM), 3) Dox (10 µM), and 4) Vit C + Dox. Dox caused a significant increase in the generation of superoxide radical (O2·-), peroxynitrite, and NO, and these effects of Dox were blunted by Vit C. Dox increased the expression of iNOS and altered protein expression as well as activation of endothelial NOS (eNOS). These changes were prevented by Vit C. Dox induced an increase in the ratio of monomeric/dimeric eNOS, promoting the production of O2·-, which was prevented by Vit C by increasing the stability of the dimeric form of eNOS. Vit C protected against the Dox-induced increase in TNFα as well as a reduction in IL-10. These results suggest that Vit C provides cardioprotection by reducing oxidative/nitrosative stress and inflammation via a modulation of Dox-induced increase in the NO levels and NOS activity.

Toll-like receptor 2 dominance over Toll-like receptor 4 in stressful conditions for its detrimental role in the heart.

It has been suggested that Toll-like receptor (TLR)4 promotes IL-10-mediated cardiac cell survival, whereas another receptor, TLR2, from the same family, is detrimental. Here, we examined the interactive role of these two innate signaling molecules under stressful conditions, including IL-10 knockout (IL-10-/-) mice, global ischemia-reperfusion (I/R) injury in rat hearts, and in vitro short hairpin RNA experimental models in the presence or absence of IL-10 (10 ng/ml). Circulating and myocardial levels of TNF-α as well as apoptosis and fibrosis were higher in IL-10-/- mice. The increase in TLR2 in IL-10-/- hearts indicated its negative regulation by IL-10. Ex vivo I/R also caused a marked upregulation of TLR2 and TNF-α as well as apoptotic and fibrotic signals. However, a 40-min reperfusion with IL-10 triggered an increase in TLR4 expression and improved recovery of cardiac function. The increase in IL-1 receptor-associated kinase (IRAK)-M and IRAK-2 activity during I/R injury suggested their role in TLR2 signaling. In vitro inhibition of TLR4 activity as a consequence of RNA inhibition-mediated suppression of myeloid differentiation gene (MyD)88 suggested MyD88-dependent activation of TLR4. The inclusion of IL-10 during reperfusion also downregulated the expression of IRAK-2, TNF-α receptor-associated factor 1-interacting protein (TRAIP) and apoptotic signals, caspase-3, and the Bax-to-Bcl-xL ratio. IL-10 reduced the TNF-α receptor-associated increase in TRAIP-induced apoptosis during I/R injury, which led to an increase in IL-1ß to mitigate transforming growth factor-ß receptor type I-mediated fibrosis. The IL-10 mitigation of these changes suggests that the stimulation through TLR4 signaling promotes IRAK-4 and phosphorylates IRAK-1 instead of IRAK-2 and may be an important therapeutic approach in restoring heart health in stress.NEW & NOTEWORTHY Under stress conditions such as downregulation of the IL-10 gene or ischemia-reperfusion injury, Toll-like receptor (TLR)4 and IL-1 receptor-associated kinase (IRAK)-1 activation is suppressed, along with the upregulation of TLR-2 and IRAK-2, resulting in fibrosis and apoptosis. It is suggested that IL-10 helps to maintain heart function during stress via myeloid differentiation gene 88/IRAK-4/IRAK-1-dependent TLR4 signaling.

Vitamin C mitigates oxidative/nitrosative stress and inflammation in doxorubicin-induced cardiomyopathy.

Increase in oxidative/nitrosative stress is one of the mechanisms associated with the development of cardiotoxicity due to doxorubicin (Dox), a potent chemotherapy drug. Previously, we reported mitigation of Dox-induced oxidative/nitrosative stress and apoptosis by vitamin C (Vit C) in isolated cardiomyocytes. In the present in vivo study in rats, we investigated the effect of prophylactic treatment with Vit C on Dox-induced apoptosis, inflammation, oxidative/nitrosative stress, cardiac dysfunction, and Vit C transporter proteins. Dox (cumulative dose: 15 mg/kg) in rats reduced systolic and diastolic cardiac function and caused structural damage. These changes were associated with a myocardial increase in reactive oxygen species, reduction in antioxidant enzyme activities, increased expression of apoptotic proteins, and inflammation. Dox also caused an increase in the expression of proapoptotic proteins Bax, Bnip-3, Bak, and caspase-3. An increase in oxidative/nitrosative stress attributable to Dox was indicated by an increase in superoxide, protein carbonyl formation, lipid peroxidation, nitric oxide (NO), NO synthase (NOS) activity, protein nitrosylation, and inducible NOS protein expression. Dox increased the levels of cardiac proinflammatory cytokines TNF-α, IL-1ß, and IL-6, whereas the expression of Vit C transporter proteins (sodium-ascorbate cotransporter 2 and glucose transporter 4) was reduced. Prophylactic and concurrent treatment with Vit C prevented all these changes and improved survival in the Vit C + Dox group. Vit C also improved Dox-mediated systolic and diastolic dysfunctions and structural damage. These results suggest a cardioprotective role of Vit C in Dox-induced cardiomyopathy by reducing oxidative/nitrosative stress, inflammation, and apoptosis, as well as improving Vit C transporter proteins.NEW & NOTEWORTHY This in vivo study provides novel data that vitamin C improves cardiac structure and function in doxorubicin-induced cardiomyopathy by reducing oxidative/nitrosative stress, apoptosis, and inflammation along with upregulation of cardiac vitamin C transporter proteins. The latter may have a crucial role in improving antioxidant status in this cardiomyopathy.

Excessive consumption of fructose causes cardiometabolic dysfunctions through oxidative stress and inflammation.

A rapid rise in obesity, as well as physical inactivity, in industrialized countries is associated with fructose-consumption-mediated metabolic syndrome having a strong association with cardiovascular disease. Although insulin resistance is thought to be at the core, visceral obesity, hypertension, and hypertriglyceridemia are also considered important components of this metabolic disorder. In addition, various other abnormalities such as inflammation, oxidative stress, and elevated levels of uric acid are also part of this syndrome. Lifestyle changes through improved physical activity, as well as nutrition, are important approaches to minimize metabolic syndrome and its deleterious effects.

Potential markers and metabolic processes involved in the mechanism of radiation-induced heart injury.

Irradiation of normal tissues leads to acute increase in reactive oxygen/nitrogen species that serve as intra- and inter-cellular signaling to alter cell and tissue function. In the case of chest irradiation, it can affect the heart, blood vessels, and lungs, with consequent tissue remodelation and adverse side effects and symptoms. This complex process is orchestrated by a large number of interacting molecular signals, including cytokines, chemokines, and growth factors. Inflammation, endothelial cell dysfunction, thrombogenesis, organ dysfunction, and ultimate failing of the heart occur as a pathological entity - "radiation-induced heart disease" (RIHD) that is major source of morbidity and mortality. The purpose of this review is to bring insights into the basic mechanisms of RIHD that may lead to the identification of targets for intervention in the radiotherapy side effect. Studies of authors also provide knowledge about how to select targeted drugs or biological molecules to modify the progression of radiation damage in the heart. New prospective studies are needed to validate that assessed factors and changes are useful as early markers of cardiac damage.

Insulin resistance: an additional risk factor in the pathogenesis of cardiovascular disease in type 2 diabetes.

Sedentary life style and high calorie dietary habits are prominent leading cause of metabolic syndrome in modern world. Obesity plays a central role in occurrence of various diseases like hyperinsulinemia, hyperglycemia and hyperlipidemia, which lead to insulin resistance and metabolic derangements like cardiovascular diseases (CVDs) mediated by oxidative stress. The mortality rate due to CVDs is on the rise in developing countries. Insulin resistance (IR) leads to micro or macro angiopathy, peripheral arterial dysfunction, hampered blood flow, hypertension, as well as the cardiomyocyte and the endothelial cell dysfunctions, thus increasing risk factors for coronary artery blockage, stroke and heart failure suggesting that there is a strong association between IR and CVDs. The plausible linkages between these two pathophysiological conditions are altered levels of insulin signaling proteins such as IR-ß, IRS-1, PI3K, Akt, Glut4 and PGC-1α that hamper insulin-mediated glucose uptake as well as other functions of insulin in the cardiomyocytes and the endothelial cells of the heart. Reduced AMPK, PFK-2 and elevated levels of NADP(H)-dependent oxidases produced by activated M1 macrophages of the adipose tissue and elevated levels of circulating angiotensin are also cause of CVD in diabetes mellitus condition. Insulin sensitizers, angiotensin blockers, superoxide scavengers are used as therapeutics in the amelioration of CVD. It evidently becomes important to unravel the mechanisms of the association between IR and CVDs in order to formulate novel efficient drugs to treat patients suffering from insulin resistance-mediated cardiovascular diseases. The possible associations between insulin resistance and cardiovascular diseases are reviewed here.

The utility of cardiac biomarkers and echocardiography for the early detection of bevacizumab- and sunitinib-mediated cardiotoxicity.

The recent introduction of novel anticancer therapies, including bevacizumab (BVZ) and sunitinib (SNT), is associated with an increased risk of cardiotoxicity. However, early identification of left ventricular (LV) systolic dysfunction may facilitate dose modification and avoid the development of advanced heart failure. Using a murine model of BVZ- and SNT-mediated cardiotoxicity, we investigated whether cardiac biomarkers and/or tissue velocity imaging (TVI) using echocardiography can detect early changes in cardiac function, before a decrease in LV ejection fraction is identified. A total of 75 wild-type C57Bl/6 male mice were treated with either 0.9% saline, BVZ, or SNT. Serial monitoring of blood pressure, high-sensitivity troponin I, and echocardiographic indexes were performed over a 14-day study period, after which the mice were euthanized for histological and biochemical analyses. Mice treated with either BVZ or SNT developed systemic hypertension as early as day 7, which increased by day 14. Cardiac biomarkers, specifically high-sensitivity troponin I, were not predictive of early LV systolic dysfunction. Although conventional LV ejection fraction values decreased at day 13 in mice treated with either BVZ or SNT, TVI confirmed early LV systolic dysfunction at day 8. Histological and biochemical analysis demonstrated loss of cellular integrity, increased oxidative stress, and increased cardiac apoptosis in mice treated with BVZ or SNT therapy at day 14. In a murine model of BVZ- or SNT-mediated cardiomyopathy, noninvasive assessment by TVI detected early LV systolic dysfunction before alterations in conventional echocardiographic indexes.

The role of renin angiotensin system antagonists in the prevention of doxorubicin and trastuzumab induced cardiotoxicity.

BACKGROUND: Cardio-Oncology is an evolving discipline that focuses on the management of cancer patients who develop cardiovascular complications as a result of their treatment. Although the current combination of surgical resection, radiation, and chemotherapy may lead to a cure in cancer patients, the administration of anti-cancer drugs, in particular Doxorubicin (DOX) and Trastuzumab (TRZ), is associated with an increased risk of cardiotoxicity. Little is known on the potential cardioprotective role of renin angiotensin system (RAS) antagonists in the prevention of DOX+TRZ mediated cardiotoxicity. OBJECTIVE: The aim of the study was to determine whether RAS antagonists would be useful in attenuating DOX+TRZ induced cardiotoxicity. METHODS: A total of 240 C57Bl/6 mice were randomized to prophylactic treatment with placebo, Aliskiren, Perindopril, or Valsartan for a total of 13 weeks. Within each arm, mice received treatment with either DOX, TRZ, or the combination of both drugs. Serial murine echocardiography was performed weekly to characterize the degree of cardiovascular remodeling within each group. RESULTS: In wild-type (WT) mice treated with DOX+TRZ, LV end diastolic internal diameter (LVID) increased from 3.1 ± 0.2 mm at baseline to 4.6 ± 0.3 mm at week 13 (p < 0.05) and the LV fractional shortening (FS) decreased from 52 ± 2% at baseline to 26 ± 2% at week 13 (p < 0.05). Prophylactic treatment with Aliskiren, Perindopril, or Valsartan attenuated the degree of LV cavity dilatation with LVID dimensions of 3.9 ± 0.2 mm, 4.1 ± 0.2 mm, and 4.2 ± 0.1 mm at week 13, respectively (p < 0.05). Similarly, prophylactic treatment with Aliskiren, Perindopril, or Valsartan was partially cardioprotective with FS of 40 ± 1%, 32 ± 1%, and 33 ± 2% at week 13, respectively (p < 0.05). As compared to WT mice receiving DOX+TRZ, prophylactic treatment with RAS inhibition was also associated with improved survival, corroborating the echocardiographic findings. CONCLUSION: The cardiotoxic effects of DOX+TRZ were partially attenuated by the prophylactic administration of RAS antagonists in a chronic murine model of chemotherapy induced cardiac dysfunction.

Preserving prostaglandin E2 level prevents rejection of implanted allogeneic mesenchymal stem cells and restores postinfarction ventricular function.

BACKGROUND: Allogeneic mesenchymal stem cells (MSCs) were immunoprivileged early after cardiac implantation and improved heart function in preclinical and clinical studies. However, long-term preclinical studies demonstrated that allogeneic MSCs lost their immunoprivilege and were rejected in the injured myocardium, resulting in recurrent ventricular dysfunction. This study identifies some of the mechanisms responsible for the immune switch in MSCs and suggests a new treatment to maintain immunoprivilege and preserve heart function. METHODS AND RESULTS: Rat MSC immunoprivilege was mediated by prostaglandin E2 (PGE2)-induced secretion of 2 critical chemokines, CCL12 and CCL5. These chemokines stimulated the chemoattraction of T cells toward MSCs, suppressed cytotoxic T-cell proliferation, and induced the production of T regulatory cells. MSCs treated with 5-azacytidine for 24 hours differentiated into myogenic cells after 2 weeks, which was associated with decreased PGE2 and chemokine production and the loss of immunoprivilege. Treatment of differentiated MSCs with PGE2 restored chemokine levels and preserved MSC immunoprivilege. In a rat myocardial infarction model, allogeneic MSCs (3 × 10(6) cells/rat) were injected into the infarct region with or without a biodegradable hydrogel that slowly released PGE2. Five weeks later, the transplanted MSCs expressed myogenic lineage markers and were rejected in the control group, but in the PGE2-treated group, the transplanted cells survived and heart function improved. CONCLUSIONS: Allogeneic MSCs maintained immunoprivilege by PGE2-induced secretion of chemokines CCL12 and CCL5. Differentiation of MSCs decreased PGE2 levels, and immunoprivilege was lost. Maintaining PGE2 levels preserved immunoprivilege after differentiation, prevented rejection of implanted MSCs, and restored cardiac function.

Catching broken hearts: pre-clinical detection of doxorubicin and trastuzumab mediated cardiac dysfunction in the breast cancer setting.

Although breast cancer is one of the leading causes of death in women worldwide, there is an overall improvement in the survival of this patient population. This is likely due to a combination of early detection through screening and awareness, improved targeted biological therapy, and an overall improvement in disease management. Despite the beneficial effects of the 2 anti-cancer drugs doxorubicin (DOX) and trastuzumab (TRZ) in women with breast cancer, development of cardiotoxicity is a major concern. The occurrence of left ventricular systolic dysfunction is unacceptably high in nearly 1 in 4 women treated with DOX+TRZ in the breast cancer setting. In this review, we explore the use of non-invasive cardiac imaging for the early detection of chemotherapy-mediated cardiotoxicity in women with breast cancer, in the hope of preventing end-stage heart disease in this cancer population.

Doxorubicin­induced cardiomyopathy is mitigated by empagliflozin via the modulation of endoplasmic reticulum stress pathways.

Doxorubicin (Dox) exhibits a high efficacy in the treatment of numerous types of cancer. However, the beneficial cytotoxic effects of Dox are often accompanied by an increase in the risk of cardiotoxicity. Oxidative stress (OS) plays a key role in Dox­induced cardiomyopathy (DIC). OS in cardiomyocytes disrupts endoplasmic reticulum (ER) function, leading to the accumulation of misfolded/unfolded proteins known as ER stress. ER stress acts as an adaptive mechanism; however, prolonged ER stress together with OS may lead to the initiation of cardiomyocyte apoptosis. The present study aimed to explore the potential of an anti­diabetic drug, empagliflozin (EMPA), in mitigating Dox­induced ER stress and cardiomyocyte apoptosis. In the present study, the effects of 1 h pretreatment of EMPA on Dox­treated cardiomyocytes isolated from Sprague­Dawley rats were investigated. After 24 h, EMPA pre­treatment promoted cell survival in the EMPA + Dox group compared with the Dox group. Results of the present study also demonstrated that EMPA mitigated overall ER stress, as the increased expression of ER stress markers was reduced in the EMPA + Dox group. Additionally, OS, inflammation and expression of ER stress apoptotic proteins were also significantly reduced following EMPA pre­treatment in the EMPA + Dox group. Thus, EMPA may exert beneficial effects on Dox­induced ER stress and may exhibit potential changes that can be utilised to further evaluate the role of EMPA in mitigating DIC.

Interleukin-10 activates Toll-like receptor 4 and requires MyD88 for cardiomyocyte survival.

Toll-like receptors (TLRs) are important in a variety of inflammatory diseases including acute cardiac disorders. TLR4 innate signaling regulates the synthesis of anti-inflammatory cytokine, interleukin-10 (IL-10) upon TLR4 agonists' re-stimulation. Anti-apoptotic action of IL-10 in cardiac dysfunction is generally accepted but its protective mechanism through TLR4 is not yet understood. We studied the effect of IL-10 in the activation of TLR4 downstream signals leading to cardiomyocytes survival. IL-10 caused a significant increase in the expression of CD14, MyD88 and TLR4. TLR4 activation led to the translocation of the interferon regulatory factor 3 (IRF3) into the nucleus. Phosphorylation of IRF3 enhanced mRNA synthesis for IL-1ß but not TNF-α and was elevated even after removal of IL-10 stimulation. Furthermore, degradation of inhibitory kappa B (IκB) kinase (Ikk) suggested that IκBß was the main activating kinase for IRF3-regulated NF-κB activation and phosphorylation of p65. Phosphorylated NF-κB p65 was translocated into the nucleus. Concomitantly, an increase in Bcl-xL activity inhibited Bax and the proteolytic activity of caspase 3 as well as a decrease in PARP cleavage. An inhibition of MyD88, modulated the above listed responses to IL-10 as there was a decrease in TLR4 and IRF3 and an increase in TNF-α mRNA. This was associated with a decrease in NF-κB p65, Bcl-xL mRNA and protein levels as well as there was an activation of Bax and PARP cleavage independent of caspase 3 activation. These data in cardiomyocytes suggest that IL-10 induced anti-apoptotic signaling involves upregulation of TLR4 through MyD88 activation.