Beta-Carotene Affects the Effects of Heme Oxygenase-1 in Isolated, Ischemic/Reperfused Rat Hearts: Potential Role of the Iron.

Beta-carotene (BC) is a well-known antioxidant. However, increasing evidence shows that under severe oxidative conditions, BC can become pro-oxidant, an effect that may be enhanced in the presence of iron (II). In our earlier studies, we observed that despite increasing heme oxygenase-1 (HO-1) levels in the heart, the protective effects of BC have been lost when it was used at a high concentration. Since iron releases from heme as a consequence of HO-1 activity, we hypothesized that the application of an iron-chelator (IC) would reverse the lost cardiac protection associated with an elevated HO-1 level. Thus, in the present study, we investigated the effects of desferrioxiamine (DFO) in isolated, ischemic/reperfused rat hearts after long-term treatment with vehicle or high-dose (HD) BC. Vehicle or 150 mg/bw kg daily doses of BC were administered to the rats for 4 weeks, and then their hearts were removed and subjected to 30 min of global ischemia (ISA) followed by 120 min of reperfusion (REP). During the experiments, cardiac function was registered, and at the end of the REP period, infarct size (IS) and HO-1 expression were measured. The results show that DFO treatment alone during REP significantly ameliorated postischemic cardiac function and decreased IS, although HO-1 expression was not increased significantly. In hearts isolated from BC-treated rats, no cardioprotective effects, despite an elevated HO-1 level, were observed, while DFO administration after ISA resulted in a mild improvement in heart function and IS. Our results suggest that iron could have a role whether BC exerts antioxidant or pro-oxidant effects in ISA/REP-injured hearts.

Basic Pharmacological Characterization of EV-34, a New H2S-Releasing Ibuprofen Derivative.

BACKGROUND: Cardioprotective effects of H2S are being suggested by numerous studies. Furthermore, H2S plays a role in relaxation of vascular smooth muscle, protects against oxidative stress, and modulates inflammation. Long-term high-dose use of NSAIDs, such as ibuprofen, have been associated with enhanced cardiovascular risk. The goal of the present work is the synthesis and basic pharmacological characterization of a newly designed H2S-releasing ibuprofen derivative. METHODS: Following the synthesis of EV-34, a new H2S-releasing derivative of ibuprofen, oxidative stability assays were performed (Fenton and porphyrin assays). Furthermore, stability of the molecule was studied in rat serum and liver lysates. H2S-releasing ability of the EC-34 was studied with a hydrogen sulfide sensor. MTT (3-(4,5-dimethylthiazol 2-yl)-2,5-(diphenyltetrazolium bromide)) assay was carried out to monitor the possible cytotoxic effect of the compound. Cyclooxygenase (COX) inhibitory property of EV-34 was also evaluated. Carrageenan assay was carried out to compare the anti-inflammatory effect of EV-34 to ibuprofen in rat paws. RESULTS: The results revealed that the molecule is stable under oxidative condition of Fenton reaction. However, EV-34 undergoes biodegradation in rat serum and liver lysates. In cell culture medium H2S is being released from EV-34. No cytotoxic effect was observed at concentrations of 10, 100, 500 µM. The COX-1 and COX-2 inhibitory effects of the molecule are comparable to those of ibuprofen. Furthermore, based on the carrageenan assay, EV-34 exhibits the same anti-inflammatory effect to that of equimolar amount of ibuprofen (100 mg/bwkg). CONCLUSION: The results indicate that EV-34 is a safe H2S releasing ibuprofen derivative bearing anti-inflammatory properties.

The Effects of Long-Term, Low- and High-Dose Beta-Carotene Treatment in Zucker Diabetic Fatty Rats: The Role of HO-1.

Nowadays, there is a growing interest in compounds derived from plants as potential raw materials for drug development. One of the most studied compounds is beta-carotene (BC). Several clinical studies can be found investigating the cardiovascular effects of BC, however, all these results are controversial. There is an increasing body of evidence showing that besides the well-known antioxidant properties, under strong oxidative circumstances, BC could become prooxidant as well. In this study, we investigated the effects of long-term, low- and high-dose BC treatment in ischemic/reperfused (ISA/REP) hearts isolated from Zucker diabetic fatty (ZDF) rats. The animals were treated with various daily doses of BC for 4 weeks and then hearts were isolated and subjected to 30 min of global ischemia (ISA) followed by 120 min of reperfusion (REP). Blood glucose levels were measured before, after two weeks, and at the end of the treatment. In isolated hearts, the myocardial function was registered. At the end of the reperfusion period, the infarct size (IS) and heme oxygenase-1 (HO-1) expression were measured. The results showed that a low dose of BC treatment significantly improved postischemic recovery, which was reflected in a decreased IS. Interestingly, when BC was applied at high concentrations, the observed protective effects were lost. Although BC treatment increased HO-1 expression, we did not observe a better heart function and/or decreased IS in the high-dose-treated group. Glucose tolerance tests showed a concentration-independent decrease in blood glucose levels. Our results suggest that long-term, low-dose BC treatment could be effective in the treatment of type-2-diabetes and related cardiovascular diseases.

Aged (Black) versus Raw Garlic against Ischemia/Reperfusion-Induced Cardiac Complications.

Recent evidence from studies suggests that aged black garlic also has an effect on health. The major aim of the present study is to compare the effect of raw and aged black garlic on postischemic cardiac recovery. Male Sprague Dawley rats were randomly divided into three groups. Animals of the first group were fed with raw garlic, animals of the second group received aged black garlic, while the third group served as vehicle-treated controls. Upon conclusion of the treatment, isolated hearts were undertaken to ischemia/reperfusion. Heart function and infarct size were measured and the level of HO-1 and iNOS were studied. Superior postischemic cardiac function and reduced infarct size in both garlic treated groups compared to the drug-free control group, indicated cardioprotective effects. However, no significant differences between the garlic treated groups were observed. Western blot analysis revealed that raw garlic enhanced the level of HO-1 before ischemia, while in ischemic samples, we found elevated HO-1 expression in both garlic treated groups. The level of iNOS was the same before ischemia in all groups, however, a markedly reduced iNOS level in ischemic/reperfused hearts originating from control and raw garlic treated animals was observed. Samples from aged black garlic treated animals demonstrated that the level of iNOS was not significantly reduced after ischemia/reperfusion. Taken together these results indicate that not only raw but also aged black garlic possess a cardioprotective effect.

Synthesis, in Vitro Biological Evaluation, and Oxidative Transformation of New Flavonol Derivatives: The Possible Role of the Phenyl-N,N-Dimethylamino Group.

Six new flavonols (6a⁻f) were synthesized with Claisen⁻Schmidt and Suzuki reactions and they were fully characterized by spectroscopic methods. In order to evaluate their antioxidant activities, their oxygen radical absorption capacity and ferric reducing antioxidant power were measured, along with their free radical scavenging activity against 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) and 2,2-diphenyl-1-picrylhydrazylradicals. In addition, their cytotoxicity on H9c2 cardiomyoblast cells was also assessed by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Compounds bearing the phenyl-N,N-dimethylamino group (6a, 6c, and 6e) exhibited promising antioxidant potency and did not have any cytotoxic effect. After a consideration of these data, the oxidative transformation of the 6c compound was investigated in vitro with a chemical Fenton reaction and the identification of the formed oxidation products was performed by mass spectrometry. Two potential metabolites were detected. Based on these results, compound 6c can be a model compound for future developments. Overall, this work has proved the involvement of the phenyl-N,N-dimethylamino group in the antioxidant activity of flavonols.

Effects of Momordica charantia (Bitter Melon) on Ischemic Diabetic Myocardium.

Objective: A rat model is here used to test a hypothesis that Momordica charantia (Bitter melon (BM)) extract favorably alters processes in cardiovascular tissue and is systemically relevant to the pathophysiology of type 2 diabetes (T2DM) and related cardiovascular disease. Methods: Male Lean and Zucker Obese (ZO) rats were gavage-treated for six weeks with 400 mg/kg body weight bitter melon (BM) extract suspended in mucin-water vehicle, or with vehicle (Control). Animals were segregated into four treatment groups, 10 animals in each group, according to strain (Lean or ZO) and treatment (Control or BM). Following six-week treatment periods, peripheral blood was collected from selected animals, followed by sacrifice, thoracotomy and mounting of isolated working heart setup. Results: Body mass of both Lean and ZO rats was unaffected by treatment, likewise, peripheral blood fasting glucose levels showed no significant treatment-related effects. However, some BM treatment-related improvement was noted in postischemic cardiac functions when Lean, BM-treated animals were compared to vehicle treated Lean control rats. Treatment of Lean, but not ZO, rats significantly reduced the magnitude of infarcted zone in isolated hearts subjected to 30 min of ischemia followed by 2 h of working mode reperfusion. Immunohistochemical demonstration of caspase-3 expression by isolated heart tissues subjected to 30 min of ischemia followed by 2 h of reperfusion, revealed significant correlation between BM treatment and reduced expression of this enzyme in hearts obtained from both Lean and ZO animals. The hierarchy and order of caspase-3 expression from highest to lowest was as follows: ZO rats receiving vehicle > ZO rats receiving BM extract > Lean rats treated receiving vehicle > Lean rats administered BM extract. Outcomes of analyses of peripheral blood content of cardiac-related analytics: with particular relevance to clinical application was a significant elevation in blood of ZO and ZO BM-treated, versus Lean rats of total cholesterol (high density lipoprotein HDL-c + low density lipoprotein LDL-c), with an inferred increase in HDL-c/LDL-c ratio-an outcome associated with decreased risk of atherosclerotic disease. Conclusions: BM extract failed to positively affect T2DM- and cardiovascular-related outcomes at a level suggesting use as a standalone treatment. Nevertheless, the encouraging effects of BM in enhancement of cardiac function, suppression of post-ischemic/reperfused infarct size extent and capacity to modulate serum cholesterol, will likely make it useful as an adjuvant therapy for the management of T2DM and related cardiovascular diseases.

Antioxidant Properties and Oxidative Transformation of Different Chromone Derivatives.

Nowadays, there is an increase in the application of natural products for the prevention of different disorders or adjuvant substances next to pharmacological treatment. Phytochemicals include different chromone derivatives, which possess a wide spectrum of biological activity. The aim of the present study was the investigation of the antioxidant activity, cytotoxicity and oxidative transformation of nine chromone derivatives. First, we investigated the radical scavenging activity (ABTS), the oxygen radical absorption capacity (ORAC) and the ferric reducing antioxidant power (FRAP) of the investigated molecules. The cytotoxic effects of the compounds were tested on H9c2 cell cultures by the MTT assay. Each compound showed a significant ORAC value compared to the reference. However, the compound 865 possess significantly higher FRAP and ABTS activity in comparison with the reference and other tested molecules, respectively. Based on these assays, the compound 865 was selected for further analysis. In these experiments, we investigated the oxidative metabolism of the compound in vitro. The molecule was oxidized by the Fenton reaction, artificial porphyrin and electrochemistry; then, the formed products were identified by mass spectrometry. Four possible metabolites were detected. The results revealed the compound 865 to possess good antioxidant properties and to be stable metabolically; hence, it is worth investigating its effects in vivo.

Cardiovascular effects of low versus high-dose beta-carotene in a rat model.

ß-carotene (BC), a lipid-soluble tetraterpene precursor to vitamin A, widely distributed in plants, including many used in human diet, has well-known health-enhancing properties, including reducing risk of and treatment for certain diseases. Nevertheless, BC may also act to promote disease through the activity of BC derivatives that form in the presence of external toxicants such as cigarette smoke and endogenously-produced reactive oxygen species. The present investigation evaluates the dose-dependent cardioprotective and possibly harmful properties of BC in a rat model. Adult male rats were gavage-fed BC for 4 weeks, at dosages of either 0, 30 or 150 mg/kg/day. Then, hearts excised from the animals were mounted in a "working heart" apparatus and subjected to 30 min of global ischemia, followed by 120 min of reperfusion. A panel of cardiac functional evaluations was conducted on each heart. Infarct size and total antioxidant capacity of the myocardium were assessed. Heart tissue content of heme oxygenase-1 (HO-1) by Western blot analysis; and potential direct cytotoxic effects of BC by MTT assay were evaluated. Hearts taken from rats receiving 30 mg/kg/day BC exhibited significantly improved heart function at lower reperfusion times, but lost this protection at higher BC dosage and longer reperfusion times. Myocardial HO-1 content was significantly elevated dose-responsively to both BC dosage. Finally, in vitro evaluation of BC on H9c2 cells showed that the agent significantly improved vitality of these cells in a dose range of 2.5-10 µM. Although data presented here do not allow for a comprehensive mechanistic explanation for reduced cardioprotection at high dose BC, it is speculated that since Fe2+ produced as a metabolite of HO-1 activity, may determine whether BC acts as an antioxidant or prooxidant agent, the strong induction of this enzyme in response to ischemia/reperfusion-induced oxidative stress may account for the high-dose BC loss of cardioprotection.

Orally delivered sour cherry seed extract (SCSE) affects cardiovascular and hematological parameters in humans.

In the present study, we investigated the effects of sour cherry seed extract (SCSE) on a variety of systemic processes that contribute to general health and viability of human subjects. The experiments were conducted according to a double-blind protocol in which six healthy individuals were administered 250-mg/day SCSE for 14 days, while four were treated with placebo. Peripheral blood was collected before and after the treatment period. Samples were analyzed for levels of selected cells, enzymes, or metabolites. Subjects that received SCSE showed increases in the values of mean cell volume, serum transferrin, mean peroxidase index, and representation of peripheral blood lymphocytes. On the other hand, decreases were observed in circulating neutrophils and ferritin levels. Changes observed in the present study do not fit into a clear pattern that might yield additional in-depth understanding of SCSE-mediated alterations in physiologic responses. The most encouraging result of the present study is the absence of any indication of toxicity by subjects consuming the extract.

Cardioprotection afforded by sour cherry seed kernel: the role of heme oxygenase-1.

Cardiovascular diseases are primary cause of death worldwide, particularly among populations with sedentary lifestyles and diets rich in animal products and processed foods. Currently, public health countermeasures to these disorders focus on costly and often marginally effective interventions administered only after the development of disease. These countermeasures are mainly palliative and fail to address the underlying causes of cardiac pathologies. Previously, the authors of this report have demonstrated that sour cherry seed kernel extract (SCSE), a nontoxic low-cost plant material, strongly preserves tissues through induction of heme oxygenase-1 (HO-1), a critical host antioxidant defense enzyme. This investigation seeks to characterize underlying mechanisms of SCSE-mediated tissue protection. Isolated hearts from Sprague-Dawley rats fed 30 mg·kg·d SCSE for 8 weeks, and untreated controls were mounted in a "working heart" apparatus and subjected to ischemia and reperfusion. A panel of cardiac functional evaluations was conducted on each heart. Infarct size assessments were made along with Western blot and immunohistochemical analysis for selected proteins involved in cardiovascular homeostasis. SCSE treatment was observed to improve postischemic cardiac functions and suppress infarct size. Analysis of the outcomes produced by this study is consistent with SCSE cardioprotection that involve interaction of Bcl-2 and HO-1.

Sour cherry seed kernel extract increases heme oxygenase-1 expression and decreases representation of CD3+ TNF-α+ and CD3+IL-8+ subpopulations in peripheral blood leukocyte cultures from type 2 diabetes patients.

The present study evaluates a hypothesis that sour cherry (Prunus cerasus) seed extracts (SCE) modulate CD3+ T lymphocyte activity in ways predictive of potential for uses of SCE in management of inflammatory diseases. Peripheral blood mononuclear cells (PBMC) from 12 type 2 diabetes (T2DM) patients and eight healthy control subjects were cultured 24 h with 100 ng/ml lipopolysaccharide (LPS) to increase inflammatory signaling and co-incubated with 0.5-100 µg/ml SCE. Cultures were evaluated by two-color flow cytometry for percent representation of CD3+ IL8+ and CD3+TNF-α cells which express interleukin-8 (IL-8), and tumor necrosis factor-α, (TNF-α+) respectively, and by enzyme-linked immunoassay for lymphocyte-associated heme oxygenase-1 (HO-1, known to be induced by SCE). SCE dosage ranges of 0.5-100 µg/ml in cell cultures significantly suppressed LPS-increased CD3+TNF-α+ and CD3+IL8+ representation from all participants (p < 0.05), with greater pharmacological effect noted in suppression of CD3+TNF-α+ noted in cells from T2DM patients versus healthy control subjects. These effects correlated with increased HO-1 expression in SCE-treated PBMC from all subjects (p < 0.05). Since TNF-α and IL-8 are diagnostic/prognostic biomarkers for many inflammatory syndromes, the capacity of SCE to down-regulate representation of cells that express them suggests potential for therapeutic use of SCE in T2DM and other diseases.

Pharmacological Evaluation of Newly Synthesized Cannabidiol Derivates on H9c2 Cells.

Cannabidiol (CBD) is a nonpsychoactive phytocannabinoid that can be found in Cannabis sativa and possesses numerous pharmacological effects. Due to these promising effects, CBD can be used in a wide variety of diseases, for instance cardiovascular diseases. However, CBD, like tetrahydrocannabinol (THC), has low bioavailability, poor water solubility, and a variable pharmacokinetic profile, which hinders its therapeutic use. Chemical derivatization of CBD offers us potential ways to overcome these issues. We prepared three new CBD derivatives substituted on the aromatic ring by Mannich-type reactions, which have not been described so far for the modification of cannabinoids, and studied the protective effect they have on cardiomyocytes exposed to oxidative stress and hypoxia/reoxygenation (H/R) compared to the parent compound. An MTT assay was performed to determine the viability of rat cardiomyocytes treated with test compounds. Trypan blue exclusion and lactate dehydrogenase (LDH) release assays were carried out to study the effect of the new compounds in cells exposed to H2O2 or hypoxia/reoxygenation (H/R). Direct antioxidant activity was evaluated by a total antioxidant capacity (TAC) assay. To study antioxidant protein levels, HO-1, SOD, catalase, and Western blot analysis were carried out. pIC50 (the negative log of the IC50) values were as follows: CBD1: 4.113, CBD2: 3.995, CBD3: 4.190, and CBD: 4.671. The newly synthesized CBD derivatives prevented cell death induced by H/R, especially CBD2. CBD has the largest direct antioxidant activity. The levels of antioxidant proteins were increased differently after pretreatment with synthetic CBD derivatives and CBD. Taken together, our newly synthesized CBD derivatives are able to decrease cytotoxicity during oxidative stress and H/R. The compounds have similar or better effects than CBD on H9c2 cells.

Postischemic cardiac recovery in heme oxygenase-1 transgenic ischemic/reperfused mouse myocardium.

Heme oxygenase-1 (HO-1) transgenic mice (Tg) were created using a rat HO-1 genomic transgene. Transgene expression was detected by RT-PCR and Western blots in the left ventricle (LV), right ventricle (RV) and septum (S) in mouse hearts, and its function was demonstrated by the elevated HO enzyme activity. Tg and non-transgenic (NTg) mouse hearts were isolated and subjected to ischemia/reperfusion. Significant post-ischemic recovery in coronary flow (CF), aortic flow (AF), aortic pressure (AOP) and first derivative of AOP (AOPdp/dt) were detected in the HO-1 Tg group compared to the NTg values. In HO-1 Tg hearts treated with 50 µmol/kg of tin protoporphyrin IX (SnPPIX), an HO enzyme inhibitor, abolished the post-ischemic cardiac recovery. HO-1 related carbon monoxide (CO) production was detected in NTg, HO-1 Tg and HO-1 Tg + SnPPIX treated groups, and a substantial increase in CO production was observed in the HO-1 Tg hearts subjected to ischemia/reperfusion. Moreover, in ischemia/reperfusion-induced tissue Na(+) and Ca(2+) gains were reduced in HO-1 Tg group in comparison with the NTg and HO-1 Tg + SnPPIX treated groups; furthermore K(+) loss was reduced in the HO-1 Tg group. The infarct size was markedly reduced from its NTg control value of 37 ± 4% to 20 ± 6% (P < 0.05) in the HO-1 Tg group, and was increased to 47 ± 5% (P < 0.05) in the HO-1 knockout (KO) hearts. Parallel to the infarct size reduction, the incidence of total and sustained ventricular fibrillation were also reduced from their NTg control values of 92% and 83% to 25% (P < 0.05) and 8% (P < 0.05) in the HO-1 Tg group, and were increased to 100% and 100% in HO-1 KO(-/-) hearts. Immunohistochemical staining of HO-1 was intensified in HO-1 Tg compared to the NTg myocardium. Thus, the HO-1 Tg mouse model suggests a valuable therapeutic approach in the treatment of ischemic myocardium.

Summative interaction between astaxanthin, Ginkgo biloba extract (EGb761) and vitamin C in suppression of respiratory inflammation: a comparison with ibuprofen.

In this study, combinations of Ginkgo biloba leaf extract (EGb761) plus the carotenoid antioxidant astaxanthin (ASX) and vitamin C were evaluated for a summative dose effect in the inhibition of asthma-associated inflammation in asthmatic guinea-pigs. Ovalbumin-sensitized Hartley guinea-pigs challenged with ovalbumin aerosol to induce asthma, were administered EGb761, ASX, vitamin C or ibuprofen. Following killing, bronchoalveolar lavage (BAL) fluid was evaluated for inflammatory cell infiltrates and lung tissue cyclic nucleotide content. Each parameter measured was significantly altered to a greater degree by drug combinations, than by each component acting independently. An optimal combination was identified that included astaxanthin (10 mg/kg), vitamin C (200 mg/kg) and EGb761 (10 mg/kg), resulting in counts of eosinophils and neutrophils each 1.6-fold lower; macrophages 1.8-fold lower, cAMP 1.4-fold higher; and cGMP 2.04-fold higher than levels in untreated, asthmatic animals (p < 0.05). In conclusion, EGb761, ASX and vitamin C are shown here to interact summatively to suppress inflammation with efficacy equal to or better than ibuprofen, a widely used non-steroidal antiinflammatory drug (NSAID). Such combinations of non-toxic phytochemicals constitute powerful tools for the prevention of onset of acute and chronic inflammatory disease if consumed regularly by healthy individuals; and may also augment the effectiveness of therapy for those with established illness.

Evaluation of systemic and dermal toxicity and dermal photoprotection by sour cherry kernels.

The present report describes outcomes of animal studies conducted to determine the systemic and dermal toxicity of Prunus cerasus (sour cherry) seed kernel contents; and a separate evaluation of the photoprotective capacity of the kernel oil fraction. B6 mice and Hartley guinea-pigs were used for these experiments. Dosage groups of 6-8 animals were administered whole kernel meal in a dose range of 0-3000 mg/kg by gavage for 8 days, following which they were killed. The liver and kidney weights were recorded and histological examination performed on sections of these organs. Kidney function was assessed as blood urea nitrogen and creatinine and liver function by measurement of serum glutamic oxaloacetic transaminase, glutamic pyruvic transaminase and alkaline phosphatase. Dermal toxicity was evaluated in a Hartley guinea-pig model by comparing UVB-irradiated shaved skin to which the kernel oil had been applied with distilled water controls. In conclusion, no evidence of toxicity was observed to result from the consumption or dermal application of sour cherry seed kernel in the dose range at which it is likely to be used in foods or healthcare. Moreover, it was shown to have a powerful capacity to protect skin from UV damage. These results suggest it will prove to be a highly safe and effective addition to a wide range of products for general use.

Preparation of Acyclovir-Containing Solid Foam by Ultrasonic Batch Technology.

In recent years, the application of solid foams has become widespread. Solid foams are not only used in the aerospace field but also in everyday life. Although foams are promising dosage forms in the pharmaceutical industry, their usage is not prevalent due to decreased stability of the solid foam structure. These special dosage forms can result in increased bioavailability of drugs. Low-density floating formulations can also increase the gastric residence time of drugs; therefore, drug release will be sustained. Our aim was to produce a stable floating formula by foaming. Matrix components, PEG 4000 and stearic acid type 50, were selected with the criteria of low gastric irritation, a melting range below 70 °C, and well-known use in oral drug formulations. This matrix was melted at 54 °C in order to produce a dispersion of active substance and was foamed by different gases at atmospheric pressure using an ultrasonic homogenizer. The density of the molded solid foam was studied by the pycnometer method, and its structure was investigated by SEM and micro-CT. The prolonged drug release and mucoadhesive properties were proved in a pH 1.2 buffer. According to our experiments, a stable foam could be produced by rapid homogenization (less than 1 min) without any surfactant material.

Reduction of reperfusion-induced ventricular fibrillation and infarct size via heme oxygenase-1 overexpression in isolated mouse hearts.

Heme oxygenase-1 (HO-1), also known as heat shock protein 32 (hsp-32) is a stress induced cytoprotective protein. The present investigation evaluated the capacity of HO-1 to reduce the incidence of reperfusion-induced ventricular fibrillation (VF) and infarct size. HO-1 transgenic (Tg) mice were generated using a rat HO-1 genomic transgene. Isolated mouse hearts obtained from Tg and nontransgenic (NTg) groups were exposed to 20 min of global ischemia and 120 min of reperfusion. Epicardial ECG was recorded to monitor the incidence of reperfusion-induced VF and at the end of the reperfusion period, detection of HO-1 by immunohistochemistry and measurement of infarct size using the TTC method were carried out. Results shown here provide additional support for cardioprotective effects of HO-1 as evidenced by the reduced infarct size. Moreover, overexpression of the HO-1 efficiently reduced the incidence of ischemia/reperfusion (I/R)-induced VF in HO-1 Tg mice.

Co-ordinated autophagy with resveratrol and γ-tocotrienol confers synergetic cardioprotection.

This study compared two dietary phytochemicals, grape-derived resveratrol and palm oil-derived γ-tocotrienol, either alone or in combination, on the contribution of autophagy in cardioprotection during ischaemia and reperfusion. Sprague-Dawley rats weighing between 250 and 300 g were randomly assigned to one of the following groups: vehicle, ischaemia/reperfusion (I/R), resveratrol + I/R, γ-tocotrienol + I/R, resveratrol +γ-tocotrienol + I/R. For resveratrol treatments, the rats were gavaged with resveratrol (2.5 mg/kg) for 15 days while for γ-tocotrienol experiments the rats were gavaged with γ-tocotrienol (0.3 mg/kg) for 30 days. For the combined resveratrol +γ-tocotrienol experiments, the rats were gavaged with γ-tocotrienol for 15 days, and then gavaging continued with resveratrol along with γ-tocotrienol for a further period of 15 days. After 30 days, isolated perfused hearts were subjected to 30 min. of global ischaemia followed by 2 hrs of reperfusion. Our results showed for the first time that at least in part, the cardioprotection (evidenced from the ventricular performance, myocardial infarct size and cardiomyocyte apoptosis) with resveratrol and γ-toctrienol was achieved by their abilities to induce autophagy. Most importantly, resveratrol and γ-tocotrienol acted synergistically providing greater degree of cardioprotection simultaneously generating greater amount of survival signal through the activation of Akt-Bcl-2 survival pathway. Autophagy was accompanied by the activation of Beclin and LC3-II as well as mTOR signalling, which were inhibited by either 3-methyl adenine (3-MA) or Wortmannin. The autophagy was confirmed from the results of transmission electron microscopy and light microscopy as well as with confocal microscopy. It is tempting to speculate that during ischaemia and reperfusion autophagy along with enhanced survival signals helps to recover the cells from injury.

Effects of Longevinex (modified resveratrol) on cardioprotection and its mechanisms of action.

Although resveratrol has been proven to possess diverse health benefits, several recent reports have demonstrated conflicting results on some aspects of its effects, including its anti-aging properties. Considerable debate appears to exist on the dose and bioavailability of resveratrol, leading to the controversies on its effectiveness. To resolve the problem, we designed a study with a resveratrol formulation that contained resveratrol supplemented with 5% quercetin and 5% rice bran phytate (commercially known as Longevinex). These ingredients were micronized to increase the bioavailability. Sprague-Dawley rats were gavaged with either Longevinex or vehicle (5% quercetin plus 5% rice bran phytate), and rats were sacrificed after 1 or 3 months, when isolated working hearts were subjected to 30 min ischemia followed by 2 h of reperfusion. Longevinex-treated hearts, irrespective of the duration of treatments, revealed superior cardiac performance, reduced infarct size, and induction of survival signals as evidenced by increased Bcl2/Bax ratio and enhanced Akt phosphorylation. In contrast, LC3-II and Beclin were enhanced significantly after 3 months of Longevinex treatment, suggesting that autophagy occurred only after feeding Longevinex to rats for a prolonged period of time. Corroborating with the results of autophagy, Sirt1 and Sirt3 increased significantly only after 3 months of Longevinex treatment, suggesting that enhanced expression of Sirts correlated with induction of autophagy. In concert, Longevinex caused phosphorylation and nuclear translocation of FoxO1, FoxO3a, and FoxO4, indicating involvement of FoxOs with autophagy. Since Sirts and FoxOs are reliable markers of longevity, the results appear to suggest that Longevinex induces longevity after prolonged feeding via induction of autophagy, while it converts death signals into survival signals and provides cardioprotection within a relatively shorter period of time.

Adrenocorticotrope hormone fragment (4-10) attenuates the ischemia/reperfusion-induced cardiac injury in isolated rat hearts.

The aim of our study was to investigate the contribution of the adrenocorticotropic hormone fragment, ACTH (4-10), on the recovery of postischemic cardiac function. Effects of ACTH (4-10) on caspase-3 activity, cardiomyocyte and endothelial apoptosis, and HO-1 protein expression were studied. Rats were treated with various doses of ACTH (4-10), and then 12 h later, anesthetized, hearts were isolated, perfused, and subjected to 30-min ischemia followed by 120-min reperfusion. Cardiac function including heart rate, coronary flow, aortic flow, and left ventricular developed pressure were recorded. After 120-min reperfusion, 200 mug/kg of ACTH (4-10) significantly improved the recovery of aortic flow, coronary flow, and left ventricular developed pressure from their untreated control values of 15.3 +/- 0.9 ml/min, 6.5 +/- 0.9 ml/min, and 10 +/- 0.6 kPa to 20.7 +/- 1.3 ml/min, 24.8 +/- 1.8 ml/min and 13.7 +/- 0.7 kPa, respectively. Heart rate did not show significant changes during reperfusion. ACTH (4-10) treatment resulted in a reduction in infarct size, caspase 3 activity, apoptosis, and an increase in HO-1 expression. When ACTH (4-10) was given at the moment of reperfusion, the drug failed to improve the postischemic recovery of the myocardium. Thus, ACTH (4-10) can be a useful tool for the prevention of the development of ischemia/reperfusion-induced injury.