Oral Glyburide, But Not Glimepiride, Blocks the Infarct-Size Limiting Effects of Pioglitazone

Background

Many patients with type 2 diabetes mellitus receive several oral hypoglycemic agents, including sulfonylurea drugs. Intravenous glyburide (Glyb), a sulfonylurea agent, blocks the protective effects of “ischemic” and pharmacologic preconditioning in various animal models without affecting myocardial infarct size when administered alone. However, there are conflicting results when other sulfonylurea drugs are used. Pioglitazone (PIO) reduces infarct size in the rat. We asked whether oral Glyb and glimepiride (Glim) affect the infarct size-limiting effects of PIO.

Methods

Sprague–Dawley rats received 3-day oral treatment with: PIO (5 mg/kg/day); PIO?+?Glyb (10 mg/kg/day); PIO?+?Glim (4 mg/kg/day) or water alone (experiment 1) or PIO (5 mg/kg/day) with or without 5-hydroxydecanoate (5HD, 10 mg/kg), a specific mitochondrial ATP-sensitive K+ channels inhibitor, administered intravenously 30 min before coronary artery ligation. PIO, Glyb and Glim were administered by oral gavage. Sugar 5% was added to water to prevent hypoglycemia. Rats underwent 30 min coronary artery occlusion and 4 h reperfusion (n?=?6 in each group). Ischemic area at risk was assessed by blue dye and infarct size by triphenyl-tetrazolium-chloride.

Results

Body weight and the size of the area at risk were comparable among groups. Infarct size (% of the area at risk) was significantly smaller in the PIO (14.3?±?1.1%; p?p?p?p?=?0.993). 5HD blocked the protective effect of PIO (infarct size 48.5?±?0.8% versus 14.8?±?0.6%, respectively; p?相似文献   

Granulocyte-Colony Stimulating Factor Reduces Cardiomyocyte Apoptosis and Ameliorates Diastolic Dysfunction in Otsuka Long-Evans Tokushima Fatty Rats

Background

In recent studies, granulocyte-colony stimulating factor (G-CSF) was shown to improve cardiac function in myocardial infarction and non-ischemic cardiomyopathies. The mechanisms of these beneficial effects of G-CSF in diabetic cardiomyopathy are not yet fully understood. Therefore, we investigated the mechanisms of action of G-CSF on diabetic cardiomyopathy in a rat model of type 2 diabetes.

Methods

Seventeen-week-old OLETF (Otsuka Long Evans Tokushima Fatty) diabetic rats and LETO (Long Evans Tokushima Otuska) rats were randomized to treatment with 5 days of G-CSF (100 μg/kg/day) or with saline. Cardiac function was evaluated by serial echocardiography performed before and 4 weeks after treatment. We measured expression of the G-CSF receptor (GCSFR) and Bcl-2, as well as the extent of apoptosis in the myocardium.

Results

G-CSF treatment significantly improved cardiac diastolic function in the serial echocardiography assessments. Expression of G-CSFR was down-regulated in the diabetic myocardium (0.03?±?0.12 % vs. 1?±?0.15 %, p?<?0.05), and its expression was stimulated by G-CSF treatment (0.03?±?0.12 % vs. 0.42?±?0.06 %, p?<?0.05). In addition, G-CSF treatment increased the expression of Bcl-2 in the diabetic myocardium (0.69?±?0.06 % vs. 0.26?±?0.11 %, p?<?0.05), consistent with the reduced cardiomyocyte apoptosis (9.38?±?0.67 % vs. 17.28?±?2.16 %, p?<?0.05).

Conclusions

Our results suggest that G-CSF might have a cardioprotective effect in diabetic cardiomyopathy through up-regulation of G-CSFR, attenuation of apoptosis by up-regulation of Bcl-2 expression, and glucose-lowering effect. Our findings support the therapeutic potential of G-CSF in diabetic cardiomyopathy.     

Liposomal Amiodarone Augments Anti-arrhythmic Effects and Reduces Hemodynamic Adverse Effects in an Ischemia/Reperfusion Rat Model

Purpose

Although amiodarone is recognized as the most effective anti-arrhythmic drug available, it has negative hemodynamic effects. Nano-sized liposomes can accumulate in and selectively deliver drugs to ischemic/reperfused (I/R) myocardium, which may augment drug effects and reduce side effects. We investigated the effects of liposomal amiodarone on lethal arrhythmias and hemodynamic parameters in an ischemia/reperfusion rat model.

Methods and Results

We prepared liposomal amiodarone (mean diameter: 113?±?8 nm) by a thin-film method. The left coronary artery of experimental rats was occluded for 5 min followed by reperfusion. Ex vivo fluorescent imaging revealed that intravenously administered fluorescent-labeled nano-sized beads accumulated in the I/R myocardium. Amiodarone was measurable in samples from the I/R myocardium when liposomal amiodarone, but not amiodarone, was administered. Although the intravenous administration of amiodarone (3 mg/kg) or liposomal amiodarone (3 mg/kg) reduced heart rate and systolic blood pressure compared with saline, the decrease in heart rate or systolic blood pressure caused by liposomal amiodarone was smaller compared with a corresponding dose of free amiodarone. The intravenous administration of liposomal amiodarone (3 mg/kg), but not free amiodarone (3 mg/kg), 5 min before ischemia showed a significantly reduced duration of lethal arrhythmias (18?±?9 s) and mortality (0 %) during the reperfusion period compared with saline (195?±?42 s, 71 %, respectively).

Conclusions

Targeting the delivery of liposomal amiodarone to ischemic/reperfused myocardium reduces the mortality due to lethal arrhythmia and the negative hemodynamic changes caused by amiodarone. Nano-size liposomes may be a promising drug delivery system for targeting I/R myocardium with cardioprotective agents.     

Mirabegron,a Clinically Approved β3 Adrenergic Receptor Agonist,Does Not Reduce Infarct Size in a Swine Model of Reperfused Myocardial Infarction

The administration of the selective β3 adrenergic receptor (β3AR) agonist BRL-37344 protects from myocardial ischemia/reperfusion injury (IRI), although the lack of clinical approval limits its translatability. We tested the cardioprotective effect of mirabegron, the first-in-class β3AR agonist approved for human use. A dose-response study was conducted in 6 pigs to select the highest intravenous dose of mirabegron without significant detrimental hemodynamic effect. Subsequently, closed chest anterior myocardial infarction (45 min ischemia followed by reperfusion) was performed in 26 pigs which randomly received either mirabegron (10 μg/kg) or placebo 5 min before reperfusion. Day-7 cardiac magnetic resonance (CMR) showed no differences in infarct size (35.0?±?2.0% of left ventricle (LV) vs. 35.9?±?2.4% in mirabegron and placebo respectively, p?=?0.782) or LV ejection fraction (36.3?±?1.1 vs. 34.6?±?1.9%, p?=?0.430). Consistent results were obtained on day-45 CMR. In conclusion, the intravenous administration of the clinically available selective β3AR agonist mirabegron does not reduce infarct size in a swine model of IRI.     

Erythropoietin (EPO) Affords More Potent Cardioprotection by Activation of Distinct Signaling to Mitochondrial Kinases Compared with Carbamylated EPO

Purpose

Erythropoietin (EPO) and its non-erythrogenic derivative, carbarmylated EPO (CEPO), have been reported to activate different receptors (homomeric EPO receptor vs. heteromeric receptor consisting of EPO receptor monomer and common β-subunit). The aim of this study was to examine differences between EPO and CEPO in efficacy of cardioprotection against infarction and in activation of pro-survival kinases.

Methods

In isolated rat hearts, infarction was induced by global ischemia followed by reperfusion. Infarct size was determined 2 h after reperfusion, and ventricular tissues for immunoblotting were sampled at 5 min after reperfusion.

Results

Pretreatment with EPO (10 units/ml) before ischemia reduced infarct size (% of risk area; %IS/AR) from 47.0?±?2.1% of the control after 20-min ischemia to 24.7?±?4.3% and from 62.0?±?3.0% after 25-min ischemia to 45.5?±?4.1%. Desialylated EPO (asialoEPO, 100 ng/ml) mimicked the protection by EPO. However, CEPO (100 ng/ml) failed to reduce infarct size after 20-min ischemia (%IS/AR?=?47.5?±?5.9%) and that after 25-min ischemia (%IS/AR?=?56.1?±?4.2%). The infarct size-limiting effect of CEPO was not shown either by increasing CEPO dose to 500 ng/ml or by shortening ischemia to 15 min. Both EPO and CEPO enhanced phosphorylation of cytosolic GSK-3β upon reperfusion. In contrast, phosphorylation of GSK-3β, Akt, and PKC-ε in mitochondria upon reperfusion was significantly enhanced by EPO but not by CEPO.

Conclusion

EPO affords more potent protection against infarction than does CEPO by distinct activation of signaling leading to phosphorylation of pro-survival protein kinases in mitochondria upon reperfusion.     

Asialoerythropoietin Exerts Stronger Angiogenic Activity than Erythropoietin Via its Binding Affinity to Tissue

Purpose

Although erythropoietin (EPO) is known to express angiogenic and cardioprotective effects, it also induces hypertension, polycythemia, and platelet activation, which may cause serious adverse effects in patients with cardiovascular diseases. We compared the angiogenic effects of EPO and its nonerythropoietic derivative, asialo-EPO (AEPO).

Methods

Lower limb ischemia was induced in ICR and C57/BL mice. Mice were injected intramuscularly with 2 μg/kg of EPO derivatives for 6 or 7 days. To assess biological differences, the tissue affinity of both EPO derivatives was analyzed in vitro using heparin affinity column chromatography. Tissue affinity was also analyzed in vivo using an intramuscular pharmacokinetic study.

Results

The survival of ischemic legs was better in the AEPO group than that in the EPO group (5/13?=?38.5 % vs 1/13?=?7.7 %, p?<?0.05), and an increase in regenerated vessels was observed in the AEPO group, but not in the EPO group in ICR mice. Vessel/muscle ratios in control, EPO, and AEPO groups were 0.50?±?0.34, 0.61?±?0.32, and 2.83?±?1.13, respectively (p?<?0.0001). On the other hand, regenerated vessels were observed in both EPO and AEPO groups (p?<?0.001) in C57/BL mice. AEPO, but not EPO, expressed heparin affinity in vitro. Intramuscularly injected EPO gradually decreased in muscle tissue, while AEPO was maintained at 2.5 ng/muscle for 1 day after several hours of a rapid clearance phase in vivo.

Conclusions

AEPO exerts stronger angiogenic effects than those of EPO presumably via its tissue affinity. Administration of AEPO is a promising option for the treatment of patients with critical limb ischemia.     

Liraglutide reverses pronounced insulin-associated weight gain,improves glycaemic control and decreases insulin dose in patients with type 2 diabetes: a 26 week,randomised clinical trial (ELEGANT)

Aims/hypothesis

The best treatment strategy for a patient with type 2 diabetes who shows pronounced weight gain after the introduction of insulin treatment is unclear. We determined whether addition of a glucagon-like peptide-1 (GLP-1) analogue could reverse pronounced insulin-associated weight gain while maintaining glycaemic control, and compared this with the most practised strategy, continuation and intensification of standard insulin therapy.

Methods

In a 26-week, randomised controlled trial (ELEGANT), conducted in the outpatient departments of one academic and one large non-academic teaching hospital in the Netherlands, adult patients with type 2 diabetes with ≥4% weight gain during short-term (≤16 months) insulin therapy received either open-label addition of liraglutide 1.8 mg/day (n?=?26) or continued standard therapy (n?=?24). A computer-generated random number list was used to allocate treatments. Participants were evaluated every 4–6 weeks for weight, glycaemic control and adverse events. The primary endpoint was between-group weight difference after 26 weeks of treatment (intention to treat).

Results

Of 50 randomised patients (mean age 58 years, BMI 33 kg/m², HbA_1c 7.4% [57 mmol/mol]), 47 (94%) completed the study; all patients were analysed. Body weight decreased by 4.5 kg with liraglutide and increased by 0.9 kg with standard therapy (mean difference ?5.2 kg [95% CI ?6.7, ?3.6 kg]; p?1c were ?0.77% (?8.4 mmol/mol) and +0.01% (+0.1 mmol/mol) (difference ?0.74% [?8.1 mmol/mol]) ([95% CI ?1.08%, ?0.41%] [?11.8, ?4.5 mmol/mol]; p?p?Conclusions/interpretation In patients with pronounced insulin-associated weight gain, addition of liraglutide to their treatment regimen reverses weight, decreases insulin dose and improves glycaemic control, and hence seems a valuable therapeutic option compared with continuation of standard insulin treatment. Trial registration ClinicalTrials.gov NCT01392898 Funding The study was funded by Novo Nordisk.     

Etanercept therapy in Behçet’s disease

Study objective

The goal of the present study was to investigate patient outcome when using the TNF receptor fusion protein etanercept in addition to conventional immunosuppressive drugs in ameliorating disease intensity and reducing relapses in refractory Behçet’s disease (BD).

Patients and methods

A single center, prospective study was conducted over 1 year. A total of 15 patients with the established diagnosis of BS were enrolled (mean age: 36.5?±?6.75 years, mean disease duration: 3.86?±?1.30 years). Clinical features were classified as refractory if the patients failed to achieve the desired response within 6 months of immunosuppressive and oral glucocorticoid therapy or flare of lesions developed while on the maximum tolerable doses of these drugs. The study included 2 patients who were on previous infliximab therapy for refractory disease. Inflammatory biomarkers (ESR and CRP) were investigated.

Results

Baseline clinical features in the study prior to inclusion showed recurrent oro-genital ulcers were observed in 100?% of patients, the pathergy test was positive in 17.6?%, ocular involvement was observed in 86.7?%, and acne lesions were recorded in 73.3?%. The following values were also recorded: mean ESR 22?±?16.97 mm/h, mean CRP level 6.87?±?4.44 mg/l, mean visual analog score 5.46?±?1.55, and mean patient global score 5.13?±?1.30. At the beginning of the study, all patients were on oral prednisolone (mean dose: 20.16?±?11.81 mg/day), azathioprine (mean dose: 126.66?±?25.81 mg/day), and oral colchicine (mean dose: 1.08?±?0.10 mg/day), then etanercept was added at a regular weekly dose of 50 mg subcutaneously for 1 year. By 8 weeks, 100?% of the patients achieve the primary endpoint, which included clinical resolution of refractory mucocutaneous, joint, and active ocular lesions with normalization of the acute phase symptoms.

Conclusion

Patients with refractory BD who received a 12-month treatment with etanercept in addition to conventional immunosuppressive therapy achieved a good therapeutic response with successful reduction of oral prednisolone to a mean dose of 6.66?±?2.24 mg/day. No serious infections or drug-related adverse events reported.     

Triple Therapy Greatly Increases Myocardial Salvage During Ischemia/Reperfusion in the in situ Rat Heart

Background

Cangrelor, a P2Y₁₂ receptor blocker, administered just prior to reperfusion reduced but did not eliminate myocardial infarction in rabbits. Combining cangrelor with ischemic postconditioning offered no additional protection suggesting they protected by a similar mechanism. To determine if cangrelor’s protection might be additive to other cardioprotective interventions we tested cangrelor in combination with ischemic preconditioning, cariporide, a sodium-hydrogen exchange blocker, and mild hypothermia.

Methods

Open-chest rats underwent 30-min coronary occlusion/2-h reperfusion.

Results

Cangrelor, administered as a bolus (60 μg/kg) 10 min before reperfusion and continued as an infusion (6 μg/kg/min) for the duration of the experiment, decreased infarction from 45.3 % of risk zone in control hearts to 25.0 %. Combining cangrelor and ischemic preconditioning offered no additional protection. Mild hypothermia (32–33 °C) instituted by peritoneal lavage with cold saline just prior to coronary occlusion resulted in 25.2 % infarction, and combining cangrelor and hypothermia nearly halved infarction to 14.1 % of risk zone. Cariporide (0.5 mg/kg) just prior to occlusion resulted in 27.2 % infarction and 15.8 % when combined with cangrelor. Combining cangrelor, hypothermia and cariporide further halved infarction to only 6.3 %. We also tested another P2Y₁₂ inhibitor ticagrelor which is chemically similar to cangrelor. Ticagrelor (20 mg/kg) fed 1 h prior to surgery reduced infarct size by an amount similar to that obtained with cangrelor (25.6 % infarction), and this protective effect was abolished by chelerythrine and wortmannin, thus implicating participation of PKC and PI3-kinase, resp., in signaling.

Conclusions

Cardioprotection from a P2Y₁₂ receptor antagonist can be combined with at least 2 other strategies to magnify the protection. Combining multiple interventions that use different cardioprotective mechanisms could provide powerful protection against infarction in patients with acute coronary thrombosis.     

Two Classes of Anti-Platelet Drugs Reduce Anatomical Infarct Size in Monkey Hearts

Background

Recent studies in rabbits have demonstrated that platelet P2Y₁₂ receptor antagonists are cardioprotective, and that the mechanism is surprisingly not related to blockade of platelet aggregation but rather to triggering of the same signal transduction pathway seen in pre- and postconditioning. We wanted to determine whether this same cardioprotection could be documented in a primate model and whether the protection was limited to P2Y₁₂ receptor antagonists or was a class effect.

Methods

Thirty-one macaque monkeys underwent 90-min LAD occlusion/4-h reperfusion.

Results

The platelet P2Y₁₂ receptor blocker cangrelor started just prior to reperfusion significantly decreased infarction by an amount equivalent to that seen with ischemic postconditioning (p?<?0.001). For any size of risk zone, infarct size in treated hearts was significantly smaller than that in control hearts. OM2, an investigational murine antibody against the primate collagen receptor glycoprotein (GP) VI, produced similar protection (p?<?0.01) suggesting a class effect. Both cangrelor and OM2 were quite effective at blocking platelet aggregation (94 % and 97 %, respectively).

Conclusions

Thus in a primate model in which infarct size could be determined directly platelet anti-aggregatory agents are cardioprotective. The important implication of these investigations is that patients with acute myocardial infarction who are treated with platelet anti-aggregatory agents prior to revascularization may already be in a postconditioned state. This hypothesis may explain why in recent clinical trials postconditioning-mimetic interventions which were so protective in animal models had at best only a modest effect.     

Remote Postconditioning Induced by Trauma Protects the Mouse Heart against Ischemia Reperfusion Injury. Involvement of the Neural Pathway and Molecular Mechanisms

Purpose

Abdominal superficial surgical incision elicits cardioprotection against myocardial ischemia reperfusion (I/R) injury in mice. This cardioprotective phenomenon, termed remote preconditioning of trauma (RPCT), results in an 80 to 85 % reduction in cardiac infarct size. We evaluated cardioprotection and the molecular mechanisms of remote postconditioning of trauma (RPostCT) in a murine I/R injury model.

Methods

Mice were analyzed using a previously established I/R injury model. An abdominal superficial surgical incision was made 45 min after myocardial ischemia at the end of coronary occlusion, and infarct size was determined 24 h after reperfusion.

Results

The results indicated that a strong cardioprotective effect occurred during RPostCT (56.94 ± 2.71 % sham vs. 15.58 ± 2.16 % RPostCT; the mean area of the infarct divided by the mean area of the region at risk; p ≤ 0.05; n = 10). Furthermore, pharmacological intervention revealed neurogenic signaling involvement in the beneficial effects of RPostCT via sensory and sympathetic thoracic nerves. Pharmacological experiments in transgenic mice demonstrated that bradykinin receptors, β-adrenergic receptors (AR), and protein kinase C were implicated in the cardioprotective effects of RPostCT.

Conclusions

RPostCT significantly decreased myocardial infarction size via neurogenic transmission and various signaling pathways. This study describes a new cardiac I/R injury prevention method that might lead to the development of therapies that are more clinically relevant for myocardial I/R injury.

     

Capsaicin-Induced Cardioprotection. Is Hypothermia or the Salvage Kinase Pathway Involved?

Purpose

Topical capsaicin application was shown to reduce infarct size in experimental animal models. We hypothesized that cardioprotective properties of topical capsaicin application could be related to its hypothermic effect.

Methods

In the first arm of the study, anesthetized rats received capsaicin cream (Caps group) or vehicle (Control group, Ctrl) applied either 15 or 30 min prior to a 30-min coronary artery occlusion followed by 2-h reperfusion. Core body temperature was allowed to run its course, and was monitored via rectal probe. At the end of the protocol, hearts were excised and risk zone and infarct size were measured. In an additional set of animals, hearts were excised immediately after a 15-min application of capsaicin/vehicle, and were used to measure phosphorylated Akt and Erk1/2 with western blots. In the second arm of the study Ctrl (n?=?6) and Caps-treated (n?=?5) animals were subjected to the same protocol as rats in the first arm, but core body temperature was maintained at 36 °C.

Results

In the first arm of the study, capsaicin produced a rapid decrease in rectal temperature ranging from 0.22 to 1.78 °C at pre-occlusion, with a median level of 0.97 °C. A capsaicin-induced temperature decrease of >0.97 °C was associated with a 31.2 % smaller infarct compared to the control group. Capsaicin treatment induced an increase in the levels of phosphorylated Akt and Erk1/2 at the end of capsaicin cream application. No increase in the phosphorylation of downstream p70S6 was observed. Levels of phosphorylated Akt- and Erk1/2 did not correlate with temperature changes after treatment. In the second arm of the study, in which body core temperature was maintained at 36 °C, no change in the infarct size was observed in the capsaicin vs. control group.

Conclusion

In the current study we for the first time demonstrated that the capsaicin induced cardioprotective effect might be related to mild hypothermia, caused by capsaicin topical application. The salvage kinase pathway appears not to be critical for capsaicin-induced cardioprotection.     

Omega-3 Polyunsaturated Fatty Acids Increase Plasma Adiponectin to Leptin Ratio in Stable Coronary Artery Disease

Background

Growing evidence suggests a cardioprotective role of omega-3 polyunsaturated fatty acids (PUFA). However, the exact mechanisms underlying the effects of omega-3 PUFA in humans have not yet been fully clarified.

Purpose

We sought to evaluate omega-3 PUFA-mediated effects on adipokines in patients with stable coronary artery disease (CAD) undergoing elective percutaneous coronary intervention (PCI).

Methods

We conducted a prospective, double-blind, placebo-controlled, randomized study, in which adiponectin, leptin and resistin were determined at baseline, 3–5 days and 30 days during administration of omega-3 PUFA 1 g/day (n?=?20) or placebo (n?=?28).

Results

As compared to controls administration of omega-3 PUFA resulted in increase of adiponectin by 13.4 % (P?<?0.0001), reduction of leptin by 22 % (P?<?0.0001) and increase of adiponectin to leptin (A/L) ratio by 45.5 % (P?<?0.0001) at 30 days, but not at 3–5 days. Compared with placebo adiponectin was 12.7 % higher (P?=?0.0042), leptin was 16.7 % lower (P?<?0.0001) and A/L ratio was 33.3 % higher (P?<?0.0001) in the omega-3 PUFA group at 30 days. Resistin decreased similarly in both groups after 1 month, without intergroup differences (P?=?0.32). The multivariate model showed that the independent predictors of changes in adiponectin at 1 month (P?<?0.001) were: omega-3 PUFA treatment, baseline platelet count, total cholesterol and those in leptin (P?<?0.0001) were: omega-3 PUFA treatment and waist circumference. Independent predictors of A/L ratio changes (P?<?0.0001) were: assigned treatment, current smoking and hyperlipidemia.

Conclusions

In high risk stable coronary patients after PCI omega-3 PUFA supplementation improves adipokine profile in circulating blood. This might be a novel, favourable mechanism of omega-3 PUFA action.     

Acute effects of statin on reduction of angiopoietin-like 2 and glyceraldehyde-derived advanced glycation end-products levels in patients with acute myocardial infarction: a message from SAMIT (Statin for Acute Myocardial Infarction Trial)

Experimental ischemia–reperfusion models have shown that 3-hydroxy-3methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, statins, have cardioprotective effects. SAMIT (Statin Acute Myocardial Infarction Trial) is a multicenter prospective open randomized trial, designed to evaluate the effects of statin treatment from the earliest stage on cardioprotection in patients with acute myocardial infarction (AMI). Patients were randomly assigned to receive atorvastatin (initial dose of 40 mg at admission followed by the maintenance dose of 10 mg/day for 30 days) or not (control), and then immediately underwent percutaneous coronary intervention (PCI) for the culprit lesion. The primary endpoints were infarct size and left ventricular function. The secondary endpoints were major adverse cardiac and cerebrovascular events (MACCE) and various biomarkers. There were no significant differences in baseline characteristics between 2 groups of the statin treatment group and the control group. The left ventricular ejection fraction increased at 6 months after the onset of AMI, compared with the baseline level in the atorvastatin group (P < 0.05), while it did not change in the control group. Although there were no significant differences in the MACCE, the changes in the levels of angiopoietin-like protein 2 (ANGPTL2) (P < 0.05), and glyceraldehyde-derived advanced glycation end-products, (TAGE) (P < 0.01) were suppressed at 2 weeks in the atorvastatin group, compared with the control group. Statin therapy started early after the onset reduced the levels of ANGPTL2 and TAGE, and thus, might have cardioprotective effects in patients with AMI.     

Saffron (Crocus sativus) intake provides nutritional preconditioning against myocardial ischemia–reperfusion injury in Wild Type and ApoE(−/−) mice: Involvement of Nrf2 activation

Background and aims

Saffron is an antioxidant herbal derivative; however, its efficacy as a nutritional cardioprotective agent has not been fully elucidated. We investigated the cardioprotective properties of a standardized saffron aqueous extract (SFE) against ischemia/reperfusion (I/R) injury in Wild-Type (WT) and ApoE^(?/?) mice and the underlying molecular mechanisms.

Chronic Metformin Associated Cardioprotection Against Infarction: Not Just a Glucose Lowering Phenomenon

Purpose

Clinical and experimental investigations demonstrated that metformin, a widely used anti-diabetic drug, exhibits cardioprotective properties against myocardial infarction. Interestingly, metformin was previously shown to increase the expression of PGC-1α a key controller of energy metabolism in skeletal muscle, which is down-regulated in diabetic conditions. We hypothesized that chronic treatment with metformin could protect the aged, diabetic heart against ischemia-reperfusion injury (IRI) by up-regulating PGC-1α and improving the impaired functionality of diabetic mitochondria.

Methods

Following 4 weeks of metformin (300 mg/kg) administered in the drinking water, 12 month-old diabetic Goto Kakizaki and non-diabetic Wistar rat hearts were assigned for infarct measurement following 35 min ischemia and 60 min reperfusion or for electron microscopy (EM) and Western blotting (WB) investigations.

Results

Metformin elicited a cardioprotective effect in both non-diabetic and diabetic hearts. In contrast with the diabetic non-treated hearts, the diabetic hearts treated with metformin showed more organized and elongated mitochondria and demonstrated a significant increase in phosphorylated AMPK and in PGC-1α expression.

Conclusions

In summary these results show for the first time that chronic metformin treatment augments myocardial resistance to ischemia-reperfusion injury, by an alternative mechanism in addition to the lowering of blood glucose. This consisted of a positive effect on mitochondrial structure possibly via a pathway involving AMPK activation and PGC-1α. Thus, metformin prescribed chronically to patients may lead to a basal state of cardioprotection thereby potentially limiting the occurrence of myocardial damage by cardiovascular events.     

Phase I/II study of the tumour-targeting human monoclonal antibody–cytokine fusion protein L19-TNF in patients with advanced solid tumours

Purpose

L19-TNF is an armed antibody that selectively targets human TNF to extra domain B-fibronectin on tumour blood vessels. We performed a phase I/II first-in-man trial with L19-TNF monotherapy in metastatic solid cancer patients to study safety and signs of clinical activity.

Methods

Six cohorts of patients were treated with increasing (1.3–13 μg/kg) doses of intravenous L19-TNF on day 1, 3, and 5 of repeated 3-weekly cycles, and 12 colorectal cancer patients were treated at 13 μg/kg. PK, antibody formation, changes in lymphocyte subsets, 5-HIAA plasma levels as well as safety and clinical activity were analysed.

Results

Thirty-four patients received at least one L19-TNF dose. The serum half-life of L19-TNF at 13 μg/kg was 33.6 min, and maximum peak serum concentration was 73.14 μg/L. Mild chills, nausea and vomiting but no haemato- or unexpected toxicity were observed. Grade 3 lumbar pain in bone metastasis was the only dose-limiting toxicity found in one patient. Objective tumour responses were not detected. Transient stable disease occurred in 19 of 31 evaluable patients.

Conclusions

Intravenous L19-TNF on day 1, 3, and 5 of a 3-weekly schedule was safe up to 13 μg/kg, but did not result in objective tumour responses. The maximally tolerated dose (MTD) was not reached, allowing for further dose escalation of L19-TNF possibly in combination with chemotherapy.     

Effects of allopurinol on cardiac function and oxidant stress in chronic intermittent hypoxia

Rationale

Obstructive sleep apnea is associated with left ventricular (LV) dysfunction, oxidant stress, and chronic intermittent hypoxia (CIH). Allopurinol (ALLO) is a xanthine oxidase inhibitor that also scavenges free radicals.

Objectives

Using an animal model of CIH we hypothesized that ALLO decreases oxidant stress and cardiac injury.

Materials and methods

Rats were exposed to either CIH (nadir 4–6%, approximately once per minute) or room air (handled controls, HC) for 8 h a day for 10 days. Four treatment groups (six to ten animals per group) were studied: CIH/ALLO, CIH/placebo (PLAC), HC/ALLO, and HC/PLAC. Outcomes included myocardial lipid peroxides (LPO) for oxidant stress, fraction shortening of the LV cavity for cardiac function (LVFS) and an assay for myocyte apoptosis.

Results

LPO was lower in CIH/ALLO group compared to CIH/PLAC (179?±?102 vs. 589?±?68 mcg/mg protein, p?<?0.05). LVFS was greater in ALLO animals than PLAC in both CIH and HC (CIH/ALLO 48.6?±?2.3% vs. CIH/PLAC 38?±?1.4%; HC/ALLO 64.9?±?1.8% vs. HC/PLAC 51.5?±?1.5%; both p?<?0.05). Terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay showed fewer apoptotic nuclei in LV myocardium in CIH/ALLO compared to CIH/PLAC (38.0?±?1.4 vs. 48.6?±?2.3 positive nuclei per 2.5 mm² area, p?<?0.05).

Conclusion

ALLO is associated with improvement in CIH-associated oxidant stress, myocardial dysfunction, and apoptosis in rats.     

Substrate metabolism during basal and hyperinsulinemic conditions in adolescents and young-adults with Barth syndrome

Background

Barth syndrome (BTHS) is a rare X-linked disorder that is characterized by mitochondrial abnormalities, infantile or childhood onset of cardioskeletal myopathy, and high mortality rates. It is currently unknown if BTHS related mitochondrial dysfunction results in substrate metabolism abnormalities and thereby contributes to cardioskeletal myopathy in patients with BTHS.

Methods

Adolescents and young adults with BTHS (n?=?5, 20?±?4 yrs) and age and activity matched healthy controls (n?=?5, 18?±?4 yrs) underwent an hyperinsulinemic-euglycemic clamp procedure with stable isotopically labeled tracers for measurement of lipolysis, fatty acid oxidation, glucose disposal, and whole-body proteolysis rates; dual energy x-ray absorptiometry for measurement of body composition and 2-D and strain echocardiography for measurement of left ventricular function.

Results

Participants with BTHS had lower fat-free mass (FFM) (BTHS: 31.4?±?6.9 vs. Control: 46.7?±?5.3 kg, p?<?0.005), lower systolic function (strain, BTHS: -15.2?±?2.4 vs. Control: ?19.0?±?2.4 %, p?<?0.05), greater insulin-stimulated glucose disposal rate per kg FFM (BTHS: 96.5?±?16.3 vs. Control: 67.4?±?17.6 μmol/kgFFM/min, p?<?0.05), lower basal (BTHS: 4.6?±?2.7 vs. Control: 11.9?±?4.4 μmol/kgFM/min, p?<?0.05) and hyperinsulinemic (BTHS: 1.6?±?0.4 vs. Control: 3.6?±?1.6 μmol/kgFM/min, p?<?0.05) lipolytic rate per kg fat mass (FM), and a trend towards higher basal leucine rate of appearance per kg FFM (BTHS: 271.4?±?69.3 vs. Control: 193.1?±?28.7 μmol/kgFFM/hr, p?=?0.07) compared to controls. Higher basal leucine rate of appearance per kg FFM (i.e. whole-body proteolytic rate) tended to be associated with lower left ventricular systolic strain (r?=??0.57, p?=?0.09).

Conclusion

Whole-body fatty acid, glucose and amino acid metabolism kinetics when expressed per unit of body composition are altered and appear to be related to cardioskeletal myopathy in humans with BTHS. Further studies examining myocardial substrate metabolism and whole-body substrate metabolism during increased energy demands (e.g., exercise) and their relationships to skeletal and cardiac function are recommended.