A Comprehensive Literature Review on Cardioprotective Effects of Bioactive Compounds Present in Fruits of Aristotelia chilensis Stuntz (Maqui).

Some fruits and vegetables, rich in bioactive compounds such as polyphenols, flavonoids, and anthocyanins, may inhibit platelet activation pathways and therefore reduce the risk of suffering from CVD when consumed regularly. Aristotelia chilensis Stuntz (Maqui) is a shrub or tree native to Chile with outstanding antioxidant activity, associated with its high content in anthocyanins, polyphenols, and flavonoids. Previous studies reveal different pharmacological properties for this berry, but its cardioprotective potential has been little studied. Despite having an abundant composition, and being rich in bioactive products with an antiplatelet role, there are few studies linking this berry with antiplatelet activity. This review summarizes and discusses relevant information on the cardioprotective potential of Maqui, based on its composition of bioactive compounds, mainly as a nutraceutical antiplatelet agent. Articles published between 2000 and 2022 in the following bibliographic databases were selected: PubMed, ScienceDirect, and Google Scholar. Our search revealed that Maqui is a promising cardiovascular target since extracts from this berry have direct effects on the reduction in cardiovascular risk factors (glucose index, obesity, diabetes, among others). Although studies on antiplatelet activity in this fruit are recent, its rich chemical composition clearly shows that the presence of chemical compounds (anthocyanins, flavonoids, phenolic acids, among others) with high antiplatelet potential can provide this berry with antiplatelet properties. These bioactive compounds have antiplatelet effects with multiple targets in the platelet, particularly, they have been related to the inhibition of thromboxane, thrombin, ADP, and GPVI receptors, or through the pathways by which these receptors stimulate platelet aggregation. Detailed studies are needed to clarify this gap in the literature, as well as to specifically evaluate the mechanism of action of Maqui extracts, due to the presence of phenolic compounds.

Regulation of arachidonic acid oxidation and metabolism by lipid electrophiles.

Arachidonic acid (AA) is a precursor of enzymatic and non-enzymatic oxidized products such as prostaglandins, thromboxanes, leukotrienes, lipoxins, and isoprostanes. These products may exert signaling or damaging roles during physiological and pathological conditions, some of them being markers of oxidative stress linked to inflammation. Recent data support the concept that cyclooxygenases (COX), lipoxygenases (LOX), and cytochrome P450 (CYP450) followed by cytosolic and microsomal dehydrogenases can convert AA to lipid-derived electrophiles (LDE). Lipid-derived electrophiles are fatty acid derivatives bearing an electron-withdrawing group that can react with nucleophiles at proteins, DNA, and small antioxidant molecules exerting potent signaling properties. This review aims to describe the formation, sources, and electrophilic anti-inflammatory actions of key mammalian LDE.

Regulation of Key Antiplatelet Pathways by Bioactive Compounds with Minimal Bleeding Risk.

Cardiovascular disease is strongly influenced by platelet activation. Platelet activation and thrombus formation at atherosclerotic plaque rupture sites is a dynamic process regulated by different signaling networks. Therefore, there are now focused efforts to search for novel bioactive compounds which target receptors and pathways in the platelet activation process while preserving normal hemostatic function. The antiplatelet activity of numerous fruits and vegetables and their multiple mechanisms of action have recently been highlighted. In this review, we review the antiplatelet actions of bioactive compounds via key pathways (protein disulfide isomerase, mitogen-activated protein kinases, mitochondrial function, cyclic adenosine monophosphate, Akt, and shear stress-induced platelet aggregation) with no effects on bleeding time. Therefore, targeting these pathways might lead to the development of effective antiplatelet strategies that do not increase the risk of bleeding.

Fatty acid nitration in human low-density lipoprotein.

Lipid nitration occurs during physiological and pathophysiological conditions, generating a variety of biomolecules capable to modulate inflammatory cell responses. Low-density lipoprotein (LDL) oxidation has been extensively related to atherosclerotic lesion development while oxidative modifications confer the particle pro-atherogenic features. Herein, we reviewed the oxidation versus nitration of human LDL protein and lipid fractions. We propose that unsaturated fatty acids present in LDL can be nitrated under mild nitration conditions, suggesting an anti-atherogenic role for LDL carrying nitro-fatty acids (NFA).

Oxidative pathways of arachidonic acid as targets for regulation of platelet activation.

Platelet activation plays an important role in acute and chronic cardiovascular disease states. Multiple pathways contribute to platelet activation including those dependent upon arachidonic acid. Arachidonic acid is released from the platelet membrane by phospholipase A2 action and is then metabolized in the cytosol by specific arachidonic acid oxidation enzymes including prostaglandin H synthase, 12-lipoxygenase, and cytochrome P450 to produce pro- and anti-inflammatory eicosanoids. This review aims to analyze the role of arachidonic acid oxidation on platelet activation, the enzymes that use it as a substrate associated as novel therapeutics target for antiplatelet drugs.

Overview of Lipid Biomarkers in Amyotrophic Lateral Sclerosis (ALS).

Amyotrophic lateral sclerosis (ALS) is a multifactorial neurodegenerative disease involving motor neuron (MN) degeneration in the spinal cord, brain stem and primary motor cortex. The existence of inflammatory processes around MN and axonal degeneration in ALS has been shown. Unfortunately, none of the successful therapies in ALS animal models has improved clinical outcomes in patients with ALS. Therefore, the detection of blood biomarkers to be used as screening tools for disease onset and progression has been an expanding research area with few advances in the development of drugs for the treatment of ALS. In this review, we will address the available data analyzing regarding the relationship of lipid metabolism and lipid derived- products with ALS. We will address the advances on the studies about the role that lipids plays at the onset, progression and lifespan extension of ALS patients.

Nitroalkylation of α-Synuclein by Nitro-Oleic Acid: Implications for Parkinson's Disease.

α-Synuclein (α-syn) represents the main component of the amyloid aggregates present in Parkinson's disease and other neurodegenerative disorders, collectively named synucleinopathies. Although α-syn is considered a natively unfolded protein, it shows great structural flexibility which allows the protein to adopt highly rich beta-sheet structures like protofibrils, oligomers and fibrils. In addition, this protein can adopt alpha-helix rich structures when interacts with fatty acids or acidic phospholipid vesicle membranes. When analyzing the toxicity of α-syn, protein oligomers are thought to be the main neurotoxic species by mechanisms that involve modification of intracellular calcium levels, mitochondrial and lysosomal function. Extracellular fibrillar α-syn promotes intracellular protein aggregation and shows many toxic effects as well. Nitro-fatty acids (nitroalkenes) represent novel pleiotropic anti-inflammatory signaling mediators that could interact with α-syn to exert unraveling actions. Herein, we demonstrated that nitro-oleic acid (NO2-OA) nitroalkylate α-syn, forming a covalent adduct at histidine-50. The nitroalkylated-α-syn exhibited strong affinity for phospholipid vesicles, moving the protein to the membrane compartment independent of composition of the membrane phospholipids. Moreover, NO2-OA-modified α-syn showed a reduced capacity to induce α-syn fibrillization compared to the non-nitrated oleic acid. From this data we hypothesize that nitroalkenes, in particular NO2-OA, may inhibit α-syn fibril formation exerting protective actions in Parkinson's disease.

Lipid Metabolism and Signaling in Platelet Function.

Modern society has changed its diet composition, transitioning to a higher intake of saturated fat with a 50% increase of cardiovascular risk (CVD). Within the context of increased CVD, there is an induction of a prothrombotic phenotype mainly due to increased platelet reactivity as well as decreased platelet response to inhibitors. Platelets maintain haemostasis through both blood components and endothelial cells that secrete inhibitory or stimulatory molecules to regulate thrombus formation. There exist a correlation between platelets' polyunsaturated fatty acid (PUFA) and the increase in platelet reactivity. The aim of this chapter is to review the metabolism of the main PUFAs involved in platelet function associated with the role that their enzyme-derived oxidized metabolites exert in platelet function and fate. Finally, how lipid metabolism in the organism affect platelet aggregation and activation and the pharmacological modulation of these processes will also be discussed.

Anti-inflammatory signaling actions of electrophilic nitro-arachidonic acid in vascular cells and astrocytes.

Nitrated derivatives of unsaturated fatty acids (nitro-fatty acids) are being formed and detected in human plasma, cell membranes and tissue, triggering signaling cascades via covalent and reversible post-translational modifications of nucleophilic amino acids in transcriptional regulatory proteins. Arachidonic acid (AA) represents a precursor of potent signaling molecules, i.e., prostaglandins and thromboxanes through enzymatic and non-enzymatic oxidative pathways. Arachidonic acid can be nitrated by reactive nitrogen species leading to the formation of nitro-arachidonic acid (NO2-AA). A critical issue is the influence of NO2-AA on prostaglandin endoperoxide H synthases, modulating inflammatory processes through redirection of AA metabolism and signaling. In this prospective article, we describe the key chemical and biochemical actions of NO2-AA in vascular and astrocytes. This includes the ability of NO2-AA to mediate unique redox signaling anti-inflammatory actions along with its therapeutic potential.

Reciprocal regulation of acetyl-CoA carboxylase 1 and senescence in human fibroblasts involves oxidant mediated p38 MAPK activation.

We sought to explore the fate of the fatty acid synthesis pathway in human fibroblasts exposed to DNA damaging agents capable of inducing senescence, a state of irreversible growth arrest. Induction of premature senescence by doxorubicin or hydrogen peroxide led to a decrease in protein and mRNA levels of acetyl-CoA carboxylase 1 (ACC1), the enzyme that catalyzes the rate-limiting step in fatty-acid biosynthesis. ACC1 decay accompanied the activation of the DNA damage response (DDR), and resulted in decreased lipid synthesis. A reduction in protein and mRNA levels of ACC1 and in lipid synthesis was also observed in human primary fibroblasts that underwent replicative senescence. We also explored the consequences of inhibiting fatty acid synthesis in proliferating non-transformed cells. Using shRNA technology, we knocked down ACC1 in human fibroblasts. Interestingly, this metabolic perturbation was sufficient to arrest proliferation and trigger the appearance of several markers of the DDR and increase senescence associated ß-galactosidase activity. Reactive oxygen species and p38 mitogen activated protein kinase phosphorylation participated in the induction of senescence. Similar results were obtained upon silencing of fatty acid synthase (FAS) expression. Together our results point towards a tight coordination of fatty acid synthesis and cell proliferation in human fibroblasts.

Nitroarachidonic acid (NO2AA) inhibits protein disulfide isomerase (PDI) through reversible covalent adduct formation with critical cysteines.

BACKGROUND: Nitroarachidonic acid (NO2AA) exhibits pleiotropic anti-inflammatory actions in a variety of cell types. We have recently shown that NO2AA inhibits phagocytic NADPH oxidase 2 (NOX2) by preventing the formation of the active complex. Recent work indicates the participation of protein disulfide isomerase (PDI) activity in NOX2 activation. Cysteine (Cys) residues at PDI active sites could be targets for NO2AA- nitroalkylation regulating PDI activity which could explain our previous observation. METHODS: PDI reductase and chaperone activities were assessed using the insulin and GFP renaturation methods in the presence or absence of NO2AA. To determine the covalent reaction with PDI as well as the site of reaction, the PEG-switch assay and LC-MS/MS studies were performed. RESULTS AND CONCLUSIONS: We determined that both activities of PDI were inhibited by NO2AA in a dose- and time- dependent manner and independent from release of nitric oxide. Since nitroalkenes are potent electrophiles and PDI has critical Cys residues for its activity, then formation of a covalent adduct between NO2AA and PDI is feasible. To this end we demonstrated the reversible covalent modification of PDI by NO2AA. Trypsinization of modified PDI confirmed that the Cys residues present in the active site a' of PDI were key targets accounting for nitroalkene modification. GENERAL SIGNIFICANCE: PDI may contribute to NOX2 activation. As such, inhibition of PDI by NO2AA might be involved in preventing NOX2 activation. Future work will be directed to determine if the covalent modifications observed play a role in the reported NO2AA inhibition of NOX2 activity.

Physiological changes associated with aging: Identification of novel biomarkers for frailty syndrome in women.

This study explores the physiological changes associated with aging that lead to frailty syndrome, characterized by reduced vitality and degeneration across multiple bodily systems, increasing susceptibility to various pathologies. While established scales like the Fried Phenotype and Frailty Trait Scale (FTS) are commonly used for assessing frailty, incorporating biomarkers is crucial for accurate diagnosis and prognosis. Our research examines plasma oxylipin levels in frail elderly individuals to identify novel biomarkers. Diagnostic criteria for frailty included assessments using the Fried Phenotype and FTS-5, with blood samples collected from 71 elderly participants (50 women and 21 men) with mean ages of 73.6 ± 5.9 and 76.2 ± 6.2 years, respectively. Women exhibited elevated platelet counts (p-value 0.0035). The significant differences in oxylipin concentrations associated with the Fried Phenotype were particularly noteworthy, predominantly observed in women. Specifically, in women, decreased grip strength (<15 kg) and slow gait speed (<0.8 m/s) correlated with increased levels of thromboxane B2 (TxB2) and 7-HDoHE (p-values 0.0404, 0.0300, 0.0033, and 0.0033, respectively). Additionally, elevated 7-HDoHE levels correlated with a BMI exceeding 28 kg/m2 (p-value 0.0123) and Physical Activity Scale for the Elderly (PASE) scores surpassing 5 points (p-value 0.0134) in women. In summary, our findings emphasize that frail older individuals, particularly women, exhibit higher levels of TxB2 and 7-HDoHE compared to their non-frail counterparts, aligning with established frailty classification and scale parameters, suggesting their potential as indicative biomarkers.

Tomato pomace-derived nitrated fatty acids: Synthesis and antiplatelet activity.

This study investigates the antiplatelet properties of tomato pulp to combat cardiovascular diseases. Notably, it examines the formation of nitrated fatty acids (NO2-FA) in tomato pomace, renowned for its potential antiplatelet effects. Through diverse assays, including tandem mass spectrometry, microplate-based platelet aggregation, and flow cytometry, the research identifies NO2-OA, NO2-LA, and NO2-LnA as pivotal antiplatelet compounds. It demonstrates the concentration-dependent antiplatelet effects of nitrated tomato pomace against thrombin receptor activator peptide 6 (TRAP-6) and collagen-induced platelet activation, alongside the modulation of platelet activation markers. Additionally, synergistic effects were observed with nitrated tomato pomace extracts. The findings suggest therapeutic potential for NO2-FA derived from tomato pomace in preventing blood clot formation, with nitrated extracts exhibiting superior efficacy compared to non-nitrated ones. This research highlights the promising role of natural products, such as tomato pomace, in mitigating cardiovascular risks and proposes novel strategies for population health enhancement and cardiovascular disease management.

Linking triphenylphosphonium cation to a bicyclic hydroquinone improves their antiplatelet effect via the regulation of mitochondrial function.

Platelets are the critical target for preventing and treating pathological thrombus formation. However, despite current antiplatelet therapy, cardiovascular mortality remains high, and cardiovascular events continue in prescribed patients. In this study, first results were obtained with ortho-carbonyl hydroquinones as antiplatelet agents; we found that linking triphenylphosphonium cation to a bicyclic ortho-carbonyl hydroquinone moiety by a short alkyl chain significantly improved their antiplatelet effect by affecting the mitochondrial functioning. The mechanism of action involves uncoupling OXPHOS, which leads to an increase in mitochondrial ROS production and a decrease in the mitochondrial membrane potential and OCR. This alteration disrupts the energy production by mitochondrial function necessary for the platelet activation process. These effects are responsive to the complete structure of the compounds and not to isolated parts of the compounds tested. The results obtained in this research can be used as the basis for developing new antiplatelet agents that target mitochondria.

An Overview of Two Old Friends Associated with Platelet Redox Signaling, the Protein Disulfide Isomerase and NADPH Oxidase.

Oxidative stress participates at the baseline of different non-communicable pathologies such as cardiovascular diseases. Excessive formation of reactive oxygen species (ROS), above the signaling levels necessary for the correct function of organelles and cells, may contribute to the non-desired effects of oxidative stress. Platelets play a relevant role in arterial thrombosis, by aggregation triggered by different agonists, where excessive ROS formation induces mitochondrial dysfunction and stimulate platelet activation and aggregation. Platelet is both a source and a target of ROS, thus we aim to analyze both the platelet enzymes responsible for ROS generation and their involvement in intracellular signal transduction pathways. Among the proteins involved in these processes are Protein Disulphide Isomerase (PDI) and NADPH oxidase (NOX) isoforms. By using bioinformatic tools and information from available databases, a complete bioinformatic analysis of the role and interactions of PDI and NOX in platelets, as well as the signal transduction pathways involved in their effects was performed. We focused the study on analyzing whether these proteins collaborate to control platelet function. The data presented in the current manuscript support the role that PDI and NOX play on activation pathways necessary for platelet activation and aggregation, as well as on the platelet signaling imbalance produced by ROS production. Our data could be used to design specific enzyme inhibitors or a dual inhibition for these enzymes with an antiplatelet effect to design promising treatments for diseases involving platelet dysfunction.

NO-IL-6/10-IL-1ß axis: a new pathway in steatotic and non-steatotic liver grafts from brain-dead donor rats.

Introduction: Brain death (BD) and steatosis are both risk factors for organ dysfunction or failure in liver transplantation (LT). Material and methods: Here, we examine the role of interleukin 6 (IL- 6) and IL-10 in LT of both non-steatotic and steatotic liver recovered from donors after brain death (DBDs), as well as the molecular signaling pathways underlying the effects of such cytokines. Results: BD reduced IL-6 levels only in nonsteatotic grafts, and diminished IL-10 levels only in steatotic ones. In both graft types, BD increased IL-1ß, which was associated with hepatic inflammation and damage. IL-6 administration reduced IL-1ß only in non-steatotic grafts and protected them against damage and inflammation. Concordantly, IL-1ß inhibition via treatment with an IL-1 receptor antagonist caused the same benefits in non-steatotic grafts. Treatment with IL-10 decreased IL-1ß only in steatotic grafts and reduced injury and inflammation specifically in this graft type. Blockading the IL-1ß effects also reduced damage and inflammation in steatotic grafts. Also, blockade of IL-1ß action diminished hepatic cAMP in both types of livers, and this was associated with a reduction in liver injury and inflammation, then pointing to IL-1ß regulating cAMP generation under LT and BD conditions. Additionally, the involvement of nitric oxide (NO) in the effects of interleukins was evaluated. Pharmacological inhibition of NO in LT from DBDs prompted even more evident reductions of IL-6 or IL-10 in non-steatotic and steatotic grafts, respectively. This exacerbated the already high levels of IL-1ß seen in LT from DBDs, causing worse damage and inflammation in both graft types. The administration of NO donors to non-steatotic grafts potentiated the beneficial effects of endogenous NO, since it increased IL-6 levels, and reduced IL-1ß, inflammation, and damage. However, treatment with NO donors in steatotic grafts did not modify IL-10 or IL-1ß levels, but induced more injurious effects tan the induction of BD alone, characterized by increased nitrotyrosine, lipid peroxidation, inflammation, and hepatic damage. Conclusion: Our study thus highlights the specificity of new signaling pathways in LT from DBDs: NO-IL-6-IL-1ß in non-steatotic livers and NO-IL-10-IL-1ß in steatotic ones. This opens up new therapeutic targets that could be useful in clinical LT.

(Poly)phenols and nitrolipids: Relevant participants in nitric oxide metabolism.

Nitric oxide (•NO) is an essential molecule able to control and regulate many biological functions. Additionally, •NO bears a potential toxicity or damaging effects under conditions of uncontrolled production, and because of its participation in redox-sensitive pathways and oxidizing reactions. Several plant (poly)phenols present in the diet are able to regulate the enzymes producing •NO (NOSs). In addition, (poly)phenols are implicated in defining •NO bioavailability, especially by regulating NADPH oxidases (NOXs), and the subsequent generation of superoxide and •NO depletion. Nitrolipids are compounds that are present in animal tissues because of dietary consumption, e.g. of olive oil, and/or as result of endogenous production. This endogenous production of nitrolipids is dependent on the nitrate/nitrite presence in the diet. Select nitrolipids, e.g. the nitroalkenes, are able to exert •NO-like signaling actions, and act as •NO reservoirs, becoming relevant for systemic •NO bioavailability. Furthermore, the presence of (poly)phenols in the stomach reduces dietary nitrite to •NO favoring nitrolipids formation. In this review we focus on the capacity of molecules representing these two groups of bioactives, i.e. (poly)phenols and nitrolipids, as relevant participants in •NO metabolism and bioavailability. This participation acquires especial relevance when human homeostasis is lost, for example under inflammatory conditions, in which the protective actions of (poly)phenols and/or nitrolipids have been associated with local and systemic •NO bioavailability.

Linking Adiposity to Interstitial Lung Disease: The Role of the Dysfunctional Adipocyte and Inflammation.

Adipose tissue has functions beyond its principal functions in energy storage, including endocrine and immune functions. When faced with a surplus of energy, the functions of adipose tissue expand by mechanisms that can be both adaptive and detrimental. These detrimental adipose tissue functions can alter normal hormonal signaling and promote local and systemic inflammation with wide-ranging consequences. Although the mechanisms by which adipose tissue triggers metabolic dysfunction and local inflammation have been well described, little is known about the relationship between adiposity and the pathogenesis of chronic lung conditions, such as interstitial lung disease (ILD). In this review, we detail the conditions and mechanisms by which adipose tissue becomes dysfunctional and relate this dysfunction to inflammatory changes observed in various forms of ILD. Finally, we review the existing basic and clinical science literature linking adiposity to ILD, highlighting the need for additional research on the mechanisms of adipocyte-mediated inflammation in ILD and its clinical implications.

The Use of Triphenyl Phosphonium Cation Enhances the Mitochondrial Antiplatelet Effect of the Compound Magnolol.

Although platelets are anucleated cells, they have fully functional mitochondria, and currently, it is known that several processes that occur in the platelet require the action of mitochondria. There are plenty of mitochondrial-targeted compounds described in the literature related to cancer, however, only a small number of studies have approached their interaction with platelet mitochondria and/or their effects on platelet activity. Recent studies have shown that magnolia extract and mitochondria-targeted magnolol can inhibit mitochondrial respiration and cell proliferation in melanoma and oral cancer cells, respectively, and they can also induce ROS and mitophagy. In this study, the effect of triphenylphosphonium cation, linked by alkyl chains of different lengths, to the organic compound magnolol on human-washed platelets was evaluated. We demonstrated that the addition of triphenylphosphonium by a four-carbon linker to magnolol (MGN4) considerably enhanced the Magnolol antiplatelet effect by a 3-fold decrease in the IC50. Additionally, platelets exposed to MGN4 5 µM showed several differences from the control including increased basal respiration, collagen-induced respiration, ATP-independent respiration, and reduced ATP-dependent respiration and non-mitochondrial respiration.

Nitroarachidonic acid, a novel peroxidase inhibitor of prostaglandin endoperoxide H synthases 1 and 2.

Prostaglandin endoperoxide H synthase (PGHS) catalyzes the oxidation of arachidonate to prostaglandin H(2). We have previously synthesized and chemically characterized nitroarachidonic acid (AANO(2)), a novel anti-inflammatory signaling mediator. Herein, the interaction of AANO(2) with PGHS was analyzed. AANO(2) inhibited oxygenase activity of PGHS-1 but not PGHS-2. AANO(2) exhibited time- and concentration-dependent inhibition of peroxidase activity in both PGHS-1 and -2. The plot of k(obs) versus AANO(2) concentrations showed a hyperbolic function with k(inact) = 0.045 s(-1) and K(i)(*app) = 0.019 µM for PGHS-1 and k(inact) = 0.057 s(-1) and K(i)(*app) = 0.020 µM for PGHS-2. Kinetic analysis suggests that inactivation of PGHS by AANO(2) involves two sequential steps: an initial reversible binding event (described by K(i)) followed by a practically irreversible event (K(i)(*app)) leading to an inactivated enzyme. Inactivation was associated with irreversible disruption of heme binding to the protein. The inhibitory effects of AANO(2) were selective because other nitro-fatty acids tested, such as nitrooleic acid and nitrolinoleic acid, were unable to inhibit enzyme activity. In activated human platelets, AANO(2) significantly decreased PGHS-1-dependent thromboxane B(2) formation in parallel with a decrease in platelet aggregation, thus confirming the biological relevance of this novel inhibitory pathway.