Antioxidant properties of pioglitazone limit nicotinamide adenine dinucleotide phosphate hydrogen oxidase and augment superoxide dismutase activity in cardiac allotransplantation

Enhanced cardioprotective activity of ferulic acid-loaded solid lipid nanoparticle in an animal model of myocardial injury

Myocardial infarction results in an increased inflammatory and oxidative stress response in the heart, and reducing inflammation and oxidative stress after MI may offer protective effects to the heart. In the present study, we examined the cardioprotective effects of ferulic acid (FA) and ferulic acid nanostructured solid lipid nanoparticles (FA-SLNs) in an isoproterenol (ISO) induced MI model. Male Sprague Dawley rats were divided into five experimental groups to compare the effects of FA and FA-SLNs. The findings revealed that ISO led to extensive cardiomyopathy, characterized by increased infarction area, edema formation, pressure load, and energy deprivation. Additionally, ISO increased the levels of inflammatory markers (COX-2, NLRP3, and NF-кB) and apoptotic mediators such as p-JNK. However, treatment with FA and FA-SLNs mitigated the severity of the ISO-induced response, and elevated the levels of antioxidant enzymes while downregulating inflammatory pathways, along with upregulation of the mitochondrial bioenergetic factor PPAR-γ. Furthermore, virtual docking analysis of FA with various protein targets supported the in vivo results, confirming drug-protein interactions. Overall, the results demonstrated that FA-SLNs offer a promising strategy for protecting the heart from further injury following MI. This is attributed to the improved drug delivery and therapeutic outcomes compared to FA alone.

Caffeic acid, a dietary polyphenol, as a promising candidate for combination therapy

Increased effectiveness and decreasing toxicity are prime objectives in drug research. Overwhelming evidence suggests the use of appropriate combination therapy for the better efficacy of drugs owing to their synergistic profile. Dietary active constituents play a major role in health outcomes. Therefore, it is possible to increase the effectiveness of the drug by combining contemporary medication with active natural/semi-synthetic constituents. One such dietary constituent, caffeic acid (CA), is a by-product of the shikimate pathway in plants and is a polyphenol of hydroxycinnamic acid class. Extensive research on CA has proposed its efficacy against inflammatory, neurodegenerative, oncologic, and metabolic disorders. The synergistic/additive effects of CA in combination with drugs like caffeine, metformin, pioglitazone, and quercetin have been reported in several experimental models and thus the present review is an attempt to consolidate outcomes of this research. Multi-target-based mechanistic studies will facilitate the development of effective combination regimens of CA.

Crocin attenuates oxidative stress and inflammation in myocardial infarction induced by isoprenaline via PPARγ activation in diabetic rats

Background and purpose

Hyperglycemia induced oxidative stress and inflammation lead to development of diabetic cardiomyopathy. Diabetic patients are more at risk for myocardial infarction than non-diabetics. The current study has investigated the involvement of PPARγ activation in effects of crocin as a natural carotenoid against cardiac infarction in diabetic rats.

Materials and methods

Diabetes was induced in male Wistar rats by streptozotocin injection (55 mg/kg, i.p) 15 min after the administration of nicotinamide (110 mg/kg). Then saline, crocin (40 mg/kg, orally) and GW9662 (1 mg/kg, as PPARγ antagonist) were injected for 4 weeks. Isoprenaline was administrated on the 27th and 28th days to induce infarction. Cardiac injury markers, antioxidant enzymes content, blood glucose level, lipid profile, pro and anti-inflammatory cytokines, and PPARγ gene expression were measured.

Results

GSH, CAT content, CK-MB isoenzyme, LDH level, IL-10 and PPARγ gene expression in myocardial tissue were decreased in diabetic rats receiving isoprenaline and inflammatory cytokines TNFα and IL-6 and also plasma lipids were increased. Crocin administration significantly ameliorated inflammatory cytokines levels, CK-MB, and LDH contents and also it could enhance antioxidant capacity and PPARγ expression. However, GW9662 administration reversed the effects of crocin.

Conclusion

Overexpression of PPARγ in crocin treated rats and inhibition of crocin effects by GW9662 reflected the potential involvement of PPARγ pathway in the protective effects of crocin.

Graphical abstract

Amelioration of High Fructose Diet-Induced Insulin Resistance, Hyperuricemia, and Liver Oxidative Stress by Combined Use of Selective Agonists of PPAR-α and PPAR-γ in Rats

Background: The use of high-fructose (Fr) corn sweeteners and sucrose in manufactured food has markedly increased recently. This excessive Fr intake has been proposed in the etiology of the metabolic syndrome, which shows an increasing prevalence throughout the world. Objective: In this study, we questioned whether fenofibrate (FF), a peroxisome proliferator-activated receptor (PPAR)-α agonist, and pioglitazone (PG), a PPAR-γ agonist, might be effective in ameliorating the metabolic syndrome in a rat model. Materials and Methods: The metabolic syndrome was induced by feeding rats a high-Fr (60%) diet for 10 weeks. The rats were divided into 5 groups: control group, fed a normal rat chow; Fr + vehicle group; Fr + FF group; Fr + PG group; and Fr + (FF + PG) group (treated with both drugs). Drug or vehicle treatment was given daily for 6 weeks (from weeks 5 to 10). Thereafter, blood and liver samples were obtained for biochemical studies. Results: Rats fed a high-Fr diet developed hyperglycemia, hyperinsulinemia, hyperuricemia, hypertriglyceri­demia, and hypercholesterolemia, and had increased serum alanine aminotransferase, hepatic tumor necrosis factor-α, and malondialdehyde levels but decreases in both glutathione content and superoxide dismutase activity. Rat treatment with FF and/or PG attenuated these alterations. The improvement was greater with the combined treatment than with either drug alone, and normalization of insulin sensitivity was observed only in rats treated with the combination therapy. Conclusion: Acting on the 2 main PPAR subfamilies, the combination of FF and PG provides a more efficacious therapy for modulating the changes in serum insulin, uric acid, and lipids, as well as the accompanying hepatic inflammation and oxidative stress that characterize the Fr-induced metabolic syndrome.

Role of the oxidative stress index, myeloperoxidase, catalase activity for cardiac allograft vasculopathy in heart transplant recipients

BACKGROUND

The aim of this study was to explore the role of oxidative stress index (OSI), myeloperoxidase (MPO), and catalase (CAT) activity in cardiac allograft vasculopathy (CAV) in heart transplant recipients (HTRs).

METHODS

The study enrolled a median age of 41 ± 9 years 47 recipients. The HTx patients were divided into two groups based on the presence CAV as follows: CAV⁽⁺⁾ and CAV^(-) group. Also, CAV⁽⁺⁾ group were divided into two groups as mild/moderate to severe CAV. The OSI, MPO, and CAT activity were analyzed in both groups.

RESULTS

The mean total antioxidant capacity (0.79 ± 0.46 vs 1.03 ± 0.33 μmol H₂ O₂ equiv/L) P = .043 was significantly lower and OSI, MPO, CAT activity were significantly higher in CAV⁽⁺⁾ group (63 ± 38 vs 20 ± 16 arbitrary unit, P = .001; 398 ± 242 vs 139  ± 112 μg/L, P = .001; 51 ± 42 vs 26 ± 23 pmol/mg protein, P = .013, respectively). Also, mean OSI (38 ± 41 vs 93 ± 75, P = .05) were significantly higher in severe CAV⁽⁺⁾ group. Recipient age, male gender, and low density lipoprotein-cholesterol were significantly higher in CAV⁽⁺⁾ group. There was a moderate correlation between the CAV grade and OSI, MPO, and CAT levels in univariate analysis (r = .560, P = .002; r = .643, P = .007; r = .681, P = .001, respectively).

CONCLUSION

An increase in the serum level of OSI, MPO, and CAT was associated with CAV in HTRs.

Experimental cardiac radiation exposure induces ventricular diastolic dysfunction with preserved ejection fraction

Breast cancer radiotherapy increases the risk of heart failure with preserved ejection fraction (HFpEF). Cardiomyocytes are highly radioresistant, but radiation specifically affects coronary microvascular endothelial cells, with subsequent microvascular inflammation and rarefaction. The effects of radiation on left ventricular (LV) diastolic function are poorly characterized. We hypothesized that cardiac radiation exposure may result in diastolic dysfunction without reduced EF. Global cardiac expression of the sodium-iodide symporter (NIS) was induced by cardiotropic gene (adeno-associated virus serotype 9) delivery to 5-wk-old rats. SPECT/CT (¹²⁵I) measurement of cardiac iodine uptake allowed calculation of the ¹³¹I doses needed to deliver 10- or 20-Gy cardiac radiation at 10 wk of age. Radiated (Rad; 10 or 20 Gy) and control rats were studied at 30 wk of age. Body weight, blood pressure, and heart rate were similar in control and Rad rats. Compared with control rats, Rad rats had impaired exercise capacity, increased LV diastolic stiffness, impaired LV relaxation, and elevated filling pressures but similar LV volume, EF, end-systolic elastance, preload recruitable stroke work, and peak +dP/dt Pathology revealed reduced microvascular density, mild concentric cardiomyocyte hypertrophy, and increased LV fibrosis in Rad rats compared with control rats. In the Rad myocardium, oxidative stress was increased and in vivo PKG activity was decreased. Experimental cardiac radiation exposure resulted in diastolic dysfunction without reduced EF. These data provide insight into the association between cardiac radiation exposure and HFpEF risk and lend further support for the importance of inflammation-related coronary microvascular compromise in HFpEF.NEW & NOTEWORTHY Cardiac radiation exposure during radiotherapy increases the risk of heart failure with preserved ejection fraction. In a novel rodent model, cardiac radiation exposure resulted in coronary microvascular rarefaction, oxidative stress, impaired PKG signaling, myocardial fibrosis, mild cardiomyocyte hypertrophy, left ventricular diastolic dysfunction, and elevated left ventricular filling pressures despite preserved ejection fraction.

The Role of Peroxisome Proliferator-Activated Receptor γ in Mediating Cardioprotection Against Ischemia/Reperfusion Injury

Myocardial infarction (MI) is a serious cardiovascular disease resulting in high rates of morbidity and mortality. Although advances have been made in restoring myocardial perfusion in ischemic areas, decreases in cardiomyocyte death and infarct size are still limited, attributing to myocardial ischemia/reperfusion (I/R) injury. It is necessary to develop therapies to restrict myocardial I/R injury and protect cardiomyocytes against further damage after MI. Many studies have suggested that peroxisome proliferator-activated receptor γ (PPARγ), a ligand-inducible nuclear receptor that predominantly regulates glucose and lipid metabolism, is a promising therapeutic target for ameliorating myocardial I/R injury. Thus, this review focuses on the role of PPARγ in cardioprotection during myocardial I/R. The cardioprotective effects of PPARγ, including attenuating oxidative stress, inhibiting inflammatory responses, improving glucose and lipid metabolism, and antagonizing apoptosis, are described. Additionally, the underlying mechanisms of cardioprotective effects of PPARγ, such as regulating the expression of target genes, influencing other transcription factors, and modulating kinase signaling pathways, are further discussed.

Alternative Interventions to Prevent Oxidative Damage following Ischemia/Reperfusion

Ischemia/reperfusion (I/R) lesions are a phenomenon that occurs in multiple pathological states and results in a series of events that end in irreparable damage that severely affects the recovery and health of patients. The principal therapeutic approaches include preconditioning, postconditioning, and remote ischemic preconditioning, which when used separately do not have a great impact on patient mortality or prognosis. Oxidative stress is known to contribute to the damage caused by I/R; however, there are no pharmacological approaches to limit or prevent this. Here, we explain the relationship between I/R and the oxidative stress process and describe some pharmacological options that may target oxidative stress-states.

Cardiac NO signalling in the metabolic syndrome

It is well documented that metabolic syndrome (i.e. a group of risk factors, such as abdominal obesity, elevated blood pressure, elevated fasting plasma glucose, high serum triglycerides and low cholesterol level in high-density lipoprotein), which raises the risk for heart disease and diabetes, is associated with increased reactive oxygen and nitrogen species (ROS/RNS) generation. ROS/RNS can modulate cardiac NO signalling and trigger various adaptive changes in NOS and antioxidant enzyme expressions/activities. While initially these changes may represent protective mechanisms in metabolic syndrome, later with more prolonged oxidative, nitrosative and nitrative stress, these are often exhausted, eventually favouring myocardial RNS generation and decreased NO bioavailability. The increased oxidative and nitrative stress also impairs the NO-soluble guanylate cyclase (sGC) signalling pathway, limiting the ability of NO to exert its fundamental signalling roles in the heart. Enhanced ROS/RNS generation in the presence of risk factors also facilitates activation of redox-dependent transcriptional factors such as NF-κB, promoting myocardial expression of various pro-inflammatory mediators, and eventually the development of cardiac dysfunction and remodelling. While the dysregulation of NO signalling may interfere with the therapeutic efficacy of conventional drugs used in the management of metabolic syndrome, the modulation of NO signalling may also be responsible for the therapeutic benefits of already proven or recently developed treatment approaches, such as ACE inhibitors, certain β-blockers, and sGC activators. Better understanding of the above-mentioned pathological processes may ultimately lead to more successful therapeutic approaches to overcome metabolic syndrome and its pathological consequences in cardiac NO signalling.

Diabetes, oxidative stress and therapeutic strategies

BACKGROUND

Diabetes has emerged as a major threat to health worldwide.

SCOPE OF REVIEW

The exact mechanisms underlying the disease are unknown; however, there is growing evidence that excess generation of reactive oxygen species (ROS), largely due to hyperglycemia, causes oxidative stress in a variety of tissues. Oxidative stress results from either an increase in free radical production, or a decrease in endogenous antioxidant defenses, or both. ROS and reactive nitrogen species (RNS) are products of cellular metabolism and are well recognized for their dual role as both deleterious and beneficial species. In type 2 diabetic patients, oxidative stress is closely associated with chronic inflammation. Multiple signaling pathways contribute to the adverse effects of glucotoxicity on cellular functions. There are many endogenous factors (antioxidants, vitamins, antioxidant enzymes, metal ion chelators) that can serve as endogenous modulators of the production and action of ROS. Clinical trials that investigated the effect of antioxidant vitamins on the progression of diabetic complications gave negative or inconclusive results. This lack of efficacy might also result from the fact that they were administered at a time when irreversible alterations in the redox status are already under way. Another strategy to modulate oxidative stress is to exploit the pleiotropic properties of drugs directed primarily at other targets and thus acting as indirect antioxidants.

MAJOR CONCLUSIONS

It appears important to develop new compounds that target key vascular ROS producing enzymes and mimic endogenous antioxidants.

GENERAL SIGNIFICANCE

This strategy might prove clinically relevant in preventing the development and/or retarding the progression of diabetes associated with vascular diseases.

Donor simvastatin treatment and cardiac allograft ischemia/reperfusion injury

Ischemia/reperfusion injury of a transplanted heart may result in serious early and late adverse effects such as primary graft dysfunction, increased allograft immunogenicity, and initiation of fibroproliferative cascades that compromise the survival of the recipient. Microvascular dysfunction has a central role in ischemia/reperfusion injury through increased vascular permeability, leukocyte adhesion and extravasation, thrombosis, vasoconstriction, and the no-reflow phenomenon. Here we review the involvement of microvascular endothelial cells and their surrounding pericytes in ischemia/reperfusion injury, and the pleiotropic, cholesterol-independent effects of statins on microvascular dysfunction. In addition, we delineate how the rapid vasculoprotective effects of statins could be used to protect cardiac allografts against ischemia/reperfusion injury by administering statins to the organ donor before graft removal and transplantation.