Amlodipine protects rat ventricular cardiomyoblast H9c2 From hypoxia-induced apoptosis and restores oxidative balance by Akt-1-dependent manner

Hesperetin ameliorates ischemia/hypoxia‐induced myocardium injury via inhibition of oxidative stress, apoptosis, and regulation of Ca 2+ homeostasis

Ischemia/hypoxia (I/H)-induced myocardial injury has a large burden worldwide. Hesperetin (HSP) has a cardioprotective effect, but the molecular mechanism underlying this is not clearly established. Here, we focused on the protective mechanisms of HSP against I/H-induced myocardium injury. H9c2 cardiomyocytes were challenged with CoCl₂ for 22 h to imitate hypoxia after treatment groups received HSP for 4 h. The viability of H9c2 cardiomyocytes was evaluated, and cardiac function indices, reactive oxygen species, apoptosis, mitochondrial membrane potential (MMP), and intracellular Ca²⁺ concentration ([Ca²⁺ ]_i ) were measured. L-type Ca²⁺ current (I_Ca-L ), myocardial contraction, and Ca²⁺ transients in isolated ventricular myocytes were also recorded. We found that HSP significantly increased the cell viability, and MMP while significantly decreasing cardiac impairment, oxidative stress, apoptosis, and [Ca²⁺ ]_i caused by CoCl₂ . Furthermore, HSP markedly attenuated I_Ca-L , myocardial contraction, and Ca²⁺ transients in a concentration-dependent manner. Our findings suggest a protective mechanism of HSP on I/H-induced myocardium injury by restoring oxidative balance, inhibiting apoptosis, improving mitochondrial function, and reducing Ca²⁺ influx via L-type Ca²⁺ channels (LTCCs). These data provide a new direction for HSP applied research as a LTCC inhibitor against I/H-induced myocardium injury.

Combinatorial therapy of exercise-preconditioning and nanocurcumin formulation supplementation improves cardiac adaptation under hypobaric hypoxia

BACKGROUND

Chronic hypobaric hypoxia (cHH) mediated cardiac insufficiencies are associated with pathological damage. Sustained redox stress and work load are major causative agents of cardiac insufficiencies under cHH. Despite the advancements made in pharmacological (anti-oxidants, vasodilators) and non-pharmacological therapeutics (acclimatization strategies and schedules), only partial success has been achieved in improving cardiac acclimatization to cHH. This necessitates the need for potent combinatorial therapies to improve cardiac acclimatization at high altitudes. We hypothesize that a combinatorial therapy comprising preconditioning to mild aerobic treadmill exercise and supplementation with nanocurcumin formulation (NCF) consisting of nanocurcumin (NC) and pyrroloquinoline quinone (PQQ) might improve cardiac adaptation at high altitudes.

METHODS

Adult Sprague-Dawley rats pre-conditioned to treadmill exercise and supplemented with NCF were exposed to cHH (7620 m altitude corresponding to pO2~8% at 28±2°C, relative humidity 55%±1%) for 3 weeks. The rat hearts were analyzed for changes in markers of oxidative stress (free radical leakage, lipid peroxidation, manganese-superoxide dismutase [MnSOD] activity), cardiac injury (circulating cardiac troponin I [TnI] and T [cTnT], myocardial creatine kinase [CK-MB]), metabolic damage (lactate dehydrogenase [LDH] and acetyl-coenzyme A levels, lactate and pyruvate levels) and bio-energetic insufficiency (ATP, p-AMPKα).

RESULTS

Significant modulations (p≤0.05) in cardiac redox status, metabolic damage, cardiac injury and bio-energetics were observed in rats receiving both NCF supplementation and treadmill exercise-preconditioning compared with rats receiving only one of the treatments.

CONCLUSIONS

The combinatorial therapeutic strategy showed a tremendous improvement in cardiac acclimatization to cHH compared to either exercise-preconditioning or NCF supplementation alone which was evident from the effective modulation in redox, metabolic, contractile and bio-energetic homeostasis.

Nanocurcumin-pyrroloquinoline formulation prevents hypertrophy-induced pathological damage by relieving mitochondrial stress in cardiomyocytes under hypoxic conditions

This study investigates the therapeutic effect of a nanocurcumin formulation (NCF) containing nanocurcumin (NC) and pyrroloquinoline quinone (PQQ) on ameliorating hypoxia-induced stress in hypertrophied primary human ventricular cardiomyocytes (HVCM) under hypoxic conditions, as validated in a Sprague-Dawley rat model of chronic hypobaric hypoxia (cHH)-induced right ventricular hypertrophy (RVH). Based on our previous findings, here, we analyzed the improvement in the protective efficacy of NCF against mitochondrial damage. The electron transport chain Complexes’ activities were analyzed as a chief operational center for mitochondrial homeostasis, along with key gene and protein markers for mitochondrial biogenesis, redox function, fatty acid oxidation, bio-energetic deficit and cell survival. NCF supplementation imparts cyto-protection from hypoxia-induced hypertrophy and damage in both in vitro and in vivo models while maintaining mitochondrial homeostasis better than NC and PQQ alone. This study proposes the use of NCF as a potential candidate molecule for imparting protection from high altitude-induced maladies in ascendants.

Nanocurcumin accords protection against acute hypobaric hypoxia induced lung injury in rats

Decline in oxygen availability experienced under hypobaric hypoxia (HH) mediates imbalance in lung fluid clearance and is a causative agent of acute lung injury. Here, we investigate the pathological events behind acute HH mediated lung injury and assess the therapeutic efficacy of nanocurcumin in its amelioration. We assess the protective efficacy of nanotized curcumin (nanocurcumin) in ameliorating HH induced lung injury and compare to curcumin. Rats exposed to acute HH (6, 12, 24, 48 and 72 h) were subjected to histopathology, blood-gas analysis and clinical biochemistry, cytokine response and redox damage. HH induced lung injury was analysed using markers of lung injury due to pulmonary vasoconstriction (ET-1/2/3 and endothelin receptors A and B) and trans-vascular fluid balance mediator (Na+/K+ ATPase). The protective efficacy of nanocurcumin was analysed by examination of Akt/Erk signalling cascade by western blot. HH induced lung injury was associated with discrete changes in blood analytes, differential circulatory cytokine response and severe pulmonary redox damages. Up-regulation of ET-1/2/3 and its receptors along with down-regulation of Na+/K+ ATPase confirmed defective pulmonary fluid clearance which promoted edema formation. Nanocurcumin treatment prevented lung edema formation and restored expression levels of ET-1/2/3 and its receptors while restoring the blood analytes, circulatory cytokines and pulmonary redox status better than curcumin. Modulation in Akt/Erk signalling pathway in rat lungs under HH confirmed the protective efficacy of nanocurcumin.

Nanocurcumin Prevents Hypoxia Induced Stress in Primary Human Ventricular Cardiomyocytes by Maintaining Mitochondrial Homeostasis

Hypoxia induced oxidative stress incurs pathophysiological changes in hypertrophied cardiomyocytes by promoting translocation of p53 to mitochondria. Here, we investigate the cardio-protective efficacy of nanocurcumin in protecting primary human ventricular cardiomyocytes (HVCM) from hypoxia induced damages. Hypoxia induced hypertrophy was confirmed by FITC-phenylalanine uptake assay, atrial natriuretic factor (ANF) levels and cell size measurements. Hypoxia induced translocation of p53 was investigated by using mitochondrial membrane permeability transition pore blocker cyclosporin A (blocks entry of p53 to mitochondria) and confirmed by western blot and immunofluorescence. Mitochondrial damage in hypertrophied HVCM cells was evaluated by analysing bio-energetic, anti-oxidant and metabolic function and substrate switching form lipids to glucose. Nanocurcumin prevented translocation of p53 to mitochondria by stabilizing mitochondrial membrane potential and de-stressed hypertrophied HVCM cells by significant restoration in lactate, acetyl-coenzyme A, pyruvate and glucose content along with lactate dehydrogenase (LDH) and 5' adenosine monophosphate-activated protein kinase (AMPKα) activity. Significant restoration in glucose and modulation of GLUT-1 and GLUT-4 levels confirmed that nanocurcumin mediated prevention of substrate switching. Nanocurcumin prevented of mitochondrial stress as confirmed by c-fos/c-jun/p53 signalling. The data indicates decrease in p-300 histone acetyl transferase (HAT) mediated histone acetylation and GATA-4 activation as pharmacological targets of nanocurcumin in preventing hypoxia induced hypertrophy. The study provides an insight into propitious therapeutic effects of nanocurcumin in cardio-protection and usability in clinical applications.

Nanocurcumin protects cardiomyoblasts H9c2 from hypoxia-induced hypertrophy and apoptosis by improving oxidative balance

Hypoxia-induced cardiomyocyte hypertrophy is evident; however, the distinct molecular mechanism underlying the oxidative stress-mediated damages to cardiomyocytes remains unknown. Curcumin (diferuloylmethane) is known for anti-hypertrophic effects, but low bioavailability makes it unsuitable to exploit its pharmacological properties. We assessed the efficacy of nanotized curcumin, i.e. nanocurcumin, in ameliorating hypoxia-induced hypertrophy and apoptosis in H9c2 cardiomyoblasts and compared it to curcumin. H9c2 cardiomyoblasts were challenged with 0.5 % oxygen, for 24 h to assess hypoxia-induced oxidative damage, hypertrophy and consequent apoptosis. The molecular mechanism underlying the protective efficacy of nanocurcumin was evaluated in regulating Raf-1/Erk-1/2 apoptosis by caspase-3/-7 pathway and oxidative stress. Nanocurcumin ameliorated hypoxia-induced hypertrophy and apoptosis in H9c2 cells significantly (p ≤ 0.01), by downregulating atrial natriuretic factor expression, caspase-3/-7 activation, oxidative stress and stabilizing hypoxia-inducible factor-1α (HIF-1α) better than curcumin. Nanocurcumin provides insight into its use as a potential candidate in curing hypoxia-induced cardiac pathologies by restoring oxidative balance.