Oxidation-sensitive mechanisms, vascular apoptosis and atherosclerosis

Human adipose-derived mesenchymal stem cells-based microspheres ameliorate atherosclerosis progression in vitro

Atherosclerosis (AS) is a chronic inflammatory disease associated with lipids deposition which could be converted into acute clinical events by thrombosis or plaque rupture. Adipose-derived mesenchymal stem cells (ADSCs) encapsulated repair units could be an effective cure for the treatment of AS patients. Here, we encapsulate human ADSCs in collagen microspheres to fabricate stem cell repair units. Besides, we show that encapsulation in collagen microspheres and cultured in vitro for 14 days maintain the viability and stemness of human ADSCs. Moreover, we generate AS progression model and niche in vitro by combining hyperlipemia serum of AS patients with AS cell models. We further systematically demonstrate that human ADSCs-based microspheres could ameliorate AS progression by inhibiting oxidative stress injure, cell apoptosis, endothelial dysfunction, inflammation, and lipid accumulation. In addition, we perform transcriptomic analysis and functional studies to demonstrate how human ADSCs (3D cultured in microspheres) respond to AS niche compared with healthy microenvironment. These findings reveal a role for ADSCs-based microspheres in the treatment of AS and provide new ideas for stem cell therapy in cardiovascular disease. The results may have implications for improving the efficiency of human ADSC therapies by illuminating the mechanisms of human ADSCs exposed in special pathological niche.

Increased Oxidative Stress Markers in Acute Ischemic Stroke Patients Treated with Thrombolytics

One of the most common neurological disorders involving oxidative stress is stroke. During a stroke, the balance of redox potential in the cell is disturbed, and, consequently, protein oxidation or other intracellular damage occurs, ultimately leading to apoptosis. The pineal gland hormone, melatonin, is one of the non-enzymatic antioxidants. It not only modulates the perianal rhythm but also has anti-inflammatory properties and protects against stress-induced changes. The focus of this research was to evaluate the concentration of the carbonyl groups and melatonin metabolite in time in patients with acute ischemic stroke that were treated with intravenous thrombolysis. This included a comparison of the functional status of patients assessed according to neurological scales with the control sample comprising healthy people. The studies showed that the serum concentrations of carbonyl groups, which were elevated in patients with ischemic stroke (AIS) in comparison to the control samples, had an impact on the patients' outcome. A urine concentration of the melatonin metabolite, which was lower in patients than controls, was related to functional status after 24 h from cerebral thrombolysis. It shows that determination of carbonyl groups at different time intervals may be an important potential marker of protein damage in patients with AIS treated with cerebral thrombolysis, and that impaired melatonin metabolism induces a low antioxidant protection. Thus, due to the neuroprotective effects of melatonin, attention should also be paid to the design and conduct of clinical trials and hormone supplementation in AIS patients to understand the interactions between exogenous melatonin and its endogenous rhythm, as well as how these relationships may affect patient outcomes.

Mitochondrial dysfunction and oxidative stress contribute to cognitive and motor impairment in FOXP1 syndrome

FOXP1 haploinsufficiency underlies cognitive and motor impairments in individuals with FOXP1 syndrome. Here, we show that mice lacking one Foxp1 copy exhibit similar behavioral deficits, which may be caused by striatal dysfunction. Indeed, Foxp1^+/− striatal medium spiny neurons display reduced neurite branching, and we show altered mitochondrial biogenesis and dynamics; increased mitophagy; reduced mitochondrial membrane potential, structure, and motility; and elevated oxygen species in the striatum of these animals. As FOXP1 is highly conserved, our data strongly suggest that mitochondrial dysfunction and excessive oxidative stress contribute to the motor and cognitive impairments seen in individuals with FOXP1 syndrome. Thus, mitochondrial homeostasis is critical for normal development and can explain deficits in neurodevelopmental disorders.

FOXP1 syndrome caused by haploinsufficiency of the forkhead box protein P1 (FOXP1) gene is a neurodevelopmental disorder that manifests motor dysfunction, intellectual disability, autism, and language impairment. In this study, we used a Foxp1^+/− mouse model to address whether cognitive and motor deficits in FOXP1 syndrome are associated with mitochondrial dysfunction and oxidative stress. Here, we show that genes with a role in mitochondrial biogenesis and dynamics (e.g., Foxo1, Pgc-1α, Tfam, Opa1, and Drp1) were dysregulated in the striatum of Foxp1^+/− mice at different postnatal stages. Furthermore, these animals exhibit a reduced mitochondrial membrane potential and complex I activity, as well as decreased expression of the antioxidants superoxide dismutase 2 (Sod2) and glutathione (GSH), resulting in increased oxidative stress and lipid peroxidation. These features can explain the reduced neurite branching, learning and memory, endurance, and motor coordination that we observed in these animals. Taken together, we provide strong evidence of mitochondrial dysfunction in Foxp1^+/− mice, suggesting that insufficient energy supply and excessive oxidative stress underlie the cognitive and motor impairment in FOXP1 deficiency.

Disrupted Mitochondrial Network Drives Deficits of Learning and Memory in a Mouse Model of FOXP1 Haploinsufficiency

Reduced cognitive flexibility, characterized by restricted interests and repetitive behavior, is associated with atypical memory performance in autism spectrum disorder (ASD), suggesting hippocampal dysfunction. FOXP1 syndrome is a neurodevelopmental disorder characterized by ASD, language deficits, global developmental delay, and mild to moderate intellectual disability. Strongly reduced Foxp1 expression has been detected in the hippocampus of Foxp1+/- mice, a brain region required for learning and memory. To investigate learning and memory performance in these animals, fear conditioning tests were carried out, which showed impaired associative learning compared with wild type (WT) animals. To shed light on the underlying mechanism, we analyzed various components of the mitochondrial network in the hippocampus. Several proteins regulating mitochondrial biogenesis (e.g., Foxo1, Pgc-1α, Tfam) and dynamics (Mfn1, Opa1, Drp1 and Fis1) were significantly dysregulated, which may explain the increased mitophagy observed in the Foxp1+/- hippocampus. The reduced activity of complex I and decreased expression of Sod2 most likely increase the production of reactive oxygen species and the expression of the pre-apoptotic proteins Bcl-2 and Bax in this tissue. In conclusion, we provide evidence that a disrupted mitochondrial network and the resulting oxidative stress in the hippocampus contribute to the altered learning and cognitive impairment in Foxp1+/- mice, suggesting that similar alterations also play a major role in patients with FOXP1 syndrome.

Potential roles of Citrulline and watermelon extract on metabolic and inflammatory variables in diabetes mellitus, current evidence and future directions: A systematic review

OBJECTIVE

Diabetes mellitus is a prevalent endocrine disorder worldwide. Citrulline is an α-amino acid, which is abundant in watermelon, and a precursor of arginine and nitric oxide. Decreased bioavailability of nitric oxide is associated with insulin resistance. The present systematic review focused on the existing evidence of citrulline and watermelon extract effects on metabolic and inflammatory parameters in diabetes mellitus.

METHODS

A systematic search of the databases PubMed, Scopus, EMBASE, ProQuest and Google Scholar was conducted for relevant papers published from inception until October 2018. All clinical trials, animal and in vitro studies published in the English language that assessed the role of citrulline and watermelon extract on diabetes mellitus, were eligible. Studies providing inadequate information were excluded.

RESULTS

Out of 1262 articles we found, only eight articles met the inclusion criteria for analysis. In three studies an increase in the synthesis of nitric oxide was reported with citrulline and watermelon extract supplementation. Four studies showed a significant reduction in blood glucose after supplementation with watermelon extract, and two studies reported a decrease in a number of inflammatory biomarkers following citrulline supplementation. Although citrulline intake caused a significant reduction in HOMA-IR in one study, inconsistent results were revealed on the effects of citrulline and watermelon extract on insulin levels and lipid profile.

CONCLUSION

Citrulline and watermelon extract could improve nitric oxide synthesis, glycaemic status and inflammation in diabetes mellitus. However, further studies are required to shed light on the underlying mechanisms.

Circulating progenitor cells and their interaction with platelets in patients with an acute coronary syndrome

CD34⁺ cells expressing KDR (CD34⁺/KDR⁺) represent a small proportion of circulating progenitor cells that have the capacity to interact with platelets and to differentiate into mature endothelial cells, thus contributing to vascular homeostasis and regeneration as well as to re-endothelialization. We investigated the levels of CD34⁺ and CD34⁺/KDR⁺ progenitor cells as well as their interaction with platelets in acute coronary syndrome (ACS) patients before the initiation (baseline) of their treatment with a P2Y₁₂ receptor antagonist, and at 5-days post-treatment (follow-up). Sixty-seven consecutive ACS patients and thirty healthy subjects (controls) participated in the study. On admission, all patients received 325 mg aspirin, followed by 100 mg/day and then were loaded either with 600 mg clopidogrel or 180 mg ticagrelor, followed by 75 mg/day (n = 36) or 90 mg × 2/day (n = 31), respectively. The levels of circulating CD34⁺ and CD34⁺/KDR⁺ progenitor cells, as well as their interaction with platelets, were determined by flow cytometry, before and after activation with ADP, in vitro. The circulating levels of CD34⁺ and CD34⁺/KDR⁺ cells in both patient groups at baseline were lower compared with controls while they were significantly increased at 5-days of follow-up in both groups, this increase being more pronounced in the ticagrelor group. The platelet/CD34⁺ (CD61⁺/CD34⁺) conjugates were higher at baseline and reduced at follow-up while the platelet/KDR⁺ (CD61⁺/KDR⁺) conjugates were lower at baseline and increased at follow-up, both changes being more pronounced in the ticagrelor group. ADP activation of control samples significantly increased the KDR expression by CD34⁺ cells and the CD61⁺/KDR⁺ conjugates, these parameters being unaffected in patients at baseline but increased at follow-up. Short-term dual antiplatelet therapy in ACS patients restores the low platelet/KDR⁺ conjugates and CD34⁺ cell levels and improves the low membrane expression levels of KDR in these cells, an effect being more pronounced in ticagrelor-treated patients. This may represent a pleiotropic effect of antiplatelet therapy towards vascular endothelial regeneration.

Proatherogenic effects of 4-hydroxynonenal

4-hydroxy-2-nonenal (HNE) is a α,β-unsaturated hydroxyalkenal generated by peroxidation of n-6 polyunsaturated fatty acid. This reactive carbonyl compound exhibits a huge number of biological properties that result mainly from the formation of HNE-adducts on free amino groups and thiol groups in proteins. In the vascular system, HNE adduct accumulation progressively leads to cellular dysfunction and tissue damages that are involved in the progression of atherosclerosis and related diseases. HNE contributes to the atherogenicity of oxidized LDL, by forming HNE-apoB adducts that deviate the LDL metabolism to the scavenger receptor pathway of macrophagic cells, and lead to the formation of foam cells. HNE activates transcription factors (Nrf2, NF-kappaB) that (dys)regulate various cellular responses ranging from hormetic and survival signaling at very low concentrations, to inflammatory and apoptotic effects at higher concentrations. Among a variety of cellular targets, HNE can modify signaling proteins involved in atherosclerotic plaque remodeling, particularly growth factor receptors (PDGFR, EGFR), cell cycle proteins, mitochondrial and endoplasmic reticulum components or extracellular matrix proteins, which progressively alters smooth muscle cell proliferation, angiogenesis and induces apoptosis. HNE adducts accumulate in the lipidic necrotic core of advanced atherosclerotic lesions, and may locally contribute to macrophage and smooth muscle cell apoptosis, which may induce plaque destabilization and rupture, thereby increasing the risk of athero-thrombotic events.

Dual signaling evoked by oxidized LDLs in vascular cells

The oxidative theory of atherosclerosis relies on the modification of low density lipoproteins (LDLs) in the vascular wall by reactive oxygen species. Modified LDLs, such as oxidized LDLs, are thought to participate in the formation of early atherosclerotic lesions (accumulation of foam cells and fatty streaks), whereas their role in advanced lesions and atherothrombotic events is more debated, because antioxidant supplementation failed to prevent coronary disease events and mortality in intervention randomized trials. As oxidized LDLs and oxidized lipids are present in atherosclerotic lesions and are able to trigger cell signaling on cultured vascular cells and macrophages, it has been proposed that they could play a role in atherogenesis and atherosclerotic vascular remodeling. Oxidized LDLs exhibit dual biological effects, which are dependent on extent of lipid peroxidation, nature of oxidized lipids (oxidized phospholipids, oxysterols, malondialdehyde, α,β-unsaturated hydroxyalkenals), concentration of oxidized LDLs and uptake by scavenger receptors (e.g. CD36, LOX-1, SRA) that signal through different transduction pathways. Moderate concentrations of mildly oxidized LDLs are proinflammatory and trigger cell migration and proliferation, whereas higher concentrations induce cell growth arrest and apoptosis. The balance between survival and apoptotic responses evoked by oxidized LDLs depends on cellular systems that regulate the cell fate, such as ceramide/sphingosine-1-phosphate rheostat, endoplasmic reticulum stress, autophagy and expression of pro/antiapoptotic proteins. In vivo, the intimal concentration of oxidized LDLs depends on the influx (hypercholesterolemia, endothelial permeability), residence time and lipid composition of LDLs, oxidative stress intensity, induction of defense mechanisms (antioxidant systems, heat shock proteins). As a consequence, the local cellular responses to oxidized LDLs may stimulate inflammatory or anti-inflammatory pathways, angiogenic or antiangiogenic responses, survival or apoptosis, thereby contributing to plaque growth, instability, complication (intraplaque hemorrhage, proteolysis, calcification, apoptosis) and rupture. Finally, these dual properties suggest that oxLDLs could be implicated at each step of atherosclerosis development, from early fatty streaks to advanced lesions, depending on the nature and concentration of their oxidized lipid content.

HSP27 Inhibits Homocysteine-Induced Endothelial Apoptosis by Modulation of ROS Production and Mitochondrial Caspase-Dependent Apoptotic Pathway

Objectives. Elevated plasma homocysteine (Hcy) could lead to endothelial dysfunction and is viewed as an independent risk factor for atherosclerosis. Heat shock protein 27 (HSP27), a small heat shock protein, is reported to exert protective effect against atherosclerosis. This study aims to investigate the protective effect of HSP27 against Hcy-induced endothelial cell apoptosis in human umbilical vein endothelial cells (HUVECs) and to determine the underlying mechanisms. Methods. Apoptosis, reactive oxygen species (ROS), and mitochondrial membrane potential (MMP) of normal or HSP27-overexpressing HUVECs in the presence of Hcy were analyzed by flow cytometry. The mRNA and protein expression levels were measured by quantitative real-time polymerase chain reaction (qRT-PCR) and western blot. Results. We found that Hcy could induce cell apoptosis with corresponding decrease of nitric oxide (NO) level, increase of endothelin-1 (ET-1), intracellular adhesion molecule-1 (ICAM-1), vascular cellular adhesion molecule-1 (VCAM-1), and monocyte chemoattractant protein-1 (MCP-1) levels, elevation of ROS, and dissipation of MMP. In addition, HSP27 could protect the cell against Hcy-induced apoptosis and inhibit the effect of Hcy on HUVECs. Furthermore, HSP27 could increase the ratio of Bcl-2/Bax and inhibit caspase-3 activity. Conclusions. Therefore, we concluded that HSP27 played a protective role against Hcy-induced endothelial apoptosis through modulation of ROS production and the mitochondrial caspase-dependent apoptotic pathway.

Voltage-Gated K+ Channel, Kv3.3 Is Involved in Hemin-Induced K562 Differentiation

Voltage-gated K⁺ (K_v) channels are well known to be involved in cell proliferation. However, even though cell proliferation is closely related to cell differentiation, the relationship between K_v channels and cell differentiation remains poorly investigated. This study demonstrates that K_v3.3 is involved in K562 cell erythroid differentiation. Down-regulation of K_v3.3 using siRNA-K_v3.3 increased hemin-induced K562 erythroid differentiation through decreased activation of signal molecules such as p38, cAMP response element-binding protein, and c-fos. Down-regulation of K_v3.3 also enhanced cell adhesion by increasing integrin β3 and this effect was amplified when the cells were cultured with fibronectin. The K_v channels, or at least K_v3.3, appear to be associated with cell differentiation; therefore, understanding the mechanisms of K_v channel regulation of cell differentiation would provide important information regarding vital cellular processes.

Antioxidant effects of statins in patients with atherosclerotic cerebrovascular disease

BACKGROUND AND PURPOSE

Oxidative stress is involved in the pathophysiological mechanisms of stroke (e.g., atherosclerosis) and brain injury after ischemic stroke. Statins, which inhibit 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, have both pleiotropic and low-density lipoprotein (LDL)-lowering properties. Recent trials have shown that high-dose statins reduce the risk of cerebrovascular events. However, there is a paucity of data regarding the changes in the oxidative stress markers in patients with atherosclerotic stroke after statin use. This study evaluated changes in oxidative stress markers after short-term use of a high-dose statin in patients with atherosclerotic stroke.

METHODS

Rosuvastatin was administered at a dose of 20 mg/day to 99 patients who had suffered an atherosclerotic stroke and no prior statin use. Blood samples were collected before and 1 month after dosing, and the serum levels of four oxidative stress markers-malondialdehyde (MDA), oxidized LDL (oxLDL), protein carbonyl content (PCO), and 8-hydroxy-2'-deoxyguanosine (8-OHdG)-were evaluated to determine the oxidation of MDA and lipids, proteins, and DNA, respectively, at both of those time points.

RESULTS

The baseline levels and the degrees of reduction after statin use differed among the oxidative stress markers measured. MDA and PCO levels were associated with infarct volumes on diffusion-weighted imaging (r=0.551, p<0.05, and r=0.444, p=0.05, respectively). Statin use decreased MDA and oxLDL levels (both p<0.05) but not the PCO or 8-OHdG level. While the reduction in MDA levels after statin use was not associated with changes in cholesterol, that in oxLDL levels was proportional to the reductions in cholesterol (r=0.479, p<0.01), LDL (r=0.459, p<0.01), and apolipoprotein B (r=0.444, p<0.05).

CONCLUSIONS

The impact of individual oxidative stress markers differs with time after ischemic stroke, suggesting that different oxidative markers reflect different aspects of oxidative stress. In addition, short-term use of a statin exerts antioxidant effects against lipid peroxidation via lipid-lowering-dependent and -independent mechanisms, but not against protein or DNA oxidation in atherosclerotic stroke patients.

Studies on two polyherbal formulations (ZPTO and ZTO) for comparison of their antidyslipidemic, antihypertensive and endothelial modulating activities

Background

Cardiovascular disorders (CVDs) are the leading cause of disease burden worldwide. Apart from available synthetic drugs used in CVDs, there are many herbal formulations including POL-10 (containing 10 herbs), which have been shown to be effective in animal studies but POL-10 was found to cause tachycardia in rodents as its side effect. This study was designed to modify the composition of POL-10 for better efficacy and/or safety profile in CVDs.

Methods

To assess the antidyslipidemic, antihypertensive and endothelial modulatory properties of two herbal formulations, (ZPTO and ZTO) containing Z: Zingiber officinalis, P: Piper nigrum, T: Terminalia belerica and O: Orchis mascula, different animal models including, tyloxapol and high fat diet-induced dyslipidemia and spontaneously hypertensive rats (SHR) were used. Effect on endothelial function was studied using isolated tissue bath set up coupled with PowerLab data acquisition system. The antioxidant activity was carried out using DPPH radical-scavenging assay.

Results

Based on preliminary screening of the ingredients of POL-10 in tyloxapol-induced hyperlipidemic rats, ZPTO and ZTO containing four active ingredients namely; Z, P, T and O were identified for further studies and comparison. In tyloxapol-induced hyperlipidemic rats, both ZPTO and ZTO caused significant reduction in serum triglyceride (TG) and total cholesterol (TC). In high fat diet-fed rats, ZPTO decreased TC, low-density lipoproteins cholesterol (LDL-C) and atherogenic index (AI). ZTO also showed similar effects to those of ZPTO with additional merits being more effective in reducing AI, body weight and more importantly raising high-density lipoproteins. In SHR, both formulations markedly reduced systolic blood pressure, AI and TG levels, ZTO being more potent in reversing endothelial dysfunction while was devoid of cardiac stimulatory effect. In addition, ZTO also reduced LDL-C and improved glucose levels in SHR. In DPPH radical-scavenging activity test, ZTO was also more potent than ZPTO.

Conclusion

The modified formulation, ZTO was not only found more effective in correcting cardiovascular abnormalities than ZPTO or POL-10 but also it was free from tachycardiac side-effect, which might be observed because of the presence of Piper nigrum in ZPTO.

A mechanism-based pharmacological evaluation of efficacy of Trigonella foenum graecum (fenugreek) seeds in regulation of dyslipidemia and oxidative stress in hyperlipidemic rats

: Alcoholic extract of Trigonella foenum graecum seeds [fenugreek seed extract (FSE)] was studied in triton-induced and high-fat diet-induced hyperlipidemia to evaluate antidyslipidemic effect. Plasma cholesterol (26.19%) and triglycerides (36.6%) were found to be lowered by FSE maximum at a dose of 200 mg/kg body weight in triton-treated hyperlipidemic rats. Chronic feeding of FSE (200 mg/kg body weight) caused lowering in plasma and hepatic lipid levels by activating lecithin-cholesterol acyltransferase (47%), postheparin lipolytic activity (35%), triglyceride lipase (34%), lipoprotein lipase (20.8%), and increased excretion of fecal bile acids (36%-45%). The FSE shows potent antioxidant activity in both in vitro and in vivo systems. It inhibited generation of superoxide anion and hydroxyl free radicals in both enzymatic and nonenzymatic systems significantly at 200 µM concentration. Furthermore, FSE normalizes the activities of antioxidant enzymes, that is, superoxide dismutase and catalase, and reduces plasma lipid peroxidation (33.9%), hepatic 4-hydroxynonenal (27%), and isoprostanes (28%). Data of the present study demonstrated that the T. foenum graecum seed extract has both antidyslipidemic and antioxidant properties.

Paeonol suppresses oxidized low-density lipoprotein induced endothelial cell apoptosis via activation of LOX-1/p38MAPK/NF-κB pathway

Paeonol is an active compound isolated from traditional Chinese medicine, and has been shown to have anti-atherosclerosis, anti-inflammatory, antioxidant effects. The present investigation was undertaken to determine the suppression effects of paeonol on oxidized low-density lipoprotein (ox-LDL) induced endothelial cell line HUVEC apoptosis and to uncover some of the underlying mechanisms of these effects. Cell viability and lactate dehydrogenase (LDH) were measured to evaluate the cell injuries. Apoptosis was evaluated by Hoechst 33342 staining and flow cytometry. Intracellular reactive oxygen species (ROS) generation was detected by 2',7'-dichlorofluorescein diacetate (DCFH-DA). Real-time PCR was used to confirm the expression of LOX-1 mRNA. Western blotting was used to evaluate the protein expression of LOX-1 and Bcl-2, as well as caspase-3 cleavage, p38-mitogen-activated protein kinase (p38MAPK) phosphorylation. NF-κB nuclear translocation was detected by Western blotting and immunofluorescence. Caspase-3 activity was measured using a colorimetric protease assay kit. The results showed that ox-LDL significantly decreased cell viability and increased the LDH release, as well as the apoptotic rate (P<0.01). Pre-treatment of paeonol resulted in remarkable increase of cell viability, decrease of LDH release and cell apoptosis in a concentration-dependent manner. Besides, ox-LDL caused the up-regulation of LOX-1, the down-regulation of Bcl-2, the phosphorylation of p38MAPK, the translocation of NF-κB and the activation of caspase-3. Paeonol pre-treatment reversed these effects introduced by ox-LDL. Moreover, paeonol also showed its inhibition effects on ox-LDL induced ROS overproduction. These results indicate the preventive effects of paeonol on ox-LDL induced endothelial cell apoptosis. The effects might, at least partly, be obtained via inhibition of LOX-1-ROS- p38MAPK-NF-κB signaling pathway.

Betaine attenuates lysophosphatidylcholine-mediated adhesion molecules in aged rat aorta: modulation of the nuclear factor-κB pathway

We previously reported that lysophosphatidylcholine (LPC) is a mediator of endothelial dysfunction in the expression of adhesion molecules (AMs) during aging. This study aimed at investigating the effects of betaine on LPC-related expression of AMs and the molecular modulation of nuclear factor-κB (NF-κB) activation in the aorta of aged rats and rat endothelial YPEN-1 cells. The experiment was performed on young (7 months) and old (21 months) rats; 2 groups of old rats were fed betaine (3 or 6 mg · kg(-1) · day(-1) for 10 days). Betaine inhibited the expression of LPC-related AMs in the serum and tissue of aged rats, without affecting the elevated levels of serum LPC. Betaine also prevented the generation of reactive species, thereby maintaining the redox status via the enhancement of the thiol status during aging. Furthermore, betaine attenuated NF-κB activation via the dephosphorylation of IκB kinase (IKK) and mitogen-activated protein kinases (MAPKs) in aged aorta and LPC-treated YPEN-1 cells. Thus, betaine suppressed the LPC-related AM expression associated with NF-κB activation via the upregulation of IKK/MAPKs. Our findings provide insights into the prevention of vascular disorders and the development of interventions based on natural compounds, such as betaine.

Lipid lowering and antioxidant effect of miglitol in triton treated hyperlipidemic and high fat diet induced obese rats

Miglitol, an anti-diabetic drug, has been shown to reduce plasma lipids and inhibit free radical generation. The anti-hyperlipidemic and antioxidant effects of miglitol were studied in triton-induced hyperlipidemic rats and high fat diet-fed obese rats. Plasma cholesterol and triglycerides levels were significantly lowered by miglitol at 100 mg/kg body weight doses. Miglitol inhibited generation of superoxide anion and hydroxyl free radicals by 14 and 31 % in enzymatic systems and 19 and 25 % in non-enzymatic systems, respectively. The in-vitro effect of the drug on adipogenesis using 3T3-L₁ preadipocytes at 2-, 5- and 10-μM concentrations showed significant inhibition of adipogenesis (34.2 %) at 10-μM concentration. High fat diet-fed rat model was used to investigate anti-hyperlipidemic, anti-obesity and antioxidant effect of miglitol. Miglitol increased the activities of lecithin-cholesterol-acyltransferase (19 %), post heparin lipolytic activity (26 %), lipoprotein lipase (26 %) and triglyceride lipase (31 %) which result in a decrease in plasma lipid levels. The antioxidant enzymes viz., catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase and thioredoxin reductase were increased by the drug in the treated animals. The antihyperlipidemic and antioxidant effect of miglitol can be correlated to its effect on different enzymes and it can be used for inhibiting the development of cardiovascular diseases.

Humanin, a cytoprotective peptide, is expressed in carotid atherosclerotic [corrected] plaques in humans

OBJECTIVE

The mechanism of atherosclerotic plaque progression leading to instability, rupture, and ischemic manifestation involves oxidative stress and apoptosis. Humanin (HN) is a newly emerging endogenously expressed cytoprotective peptide. Our goal was to determine the presence and localization of HN in carotid atherosclerotic plaques.

METHODS AND RESULTS

Plaque specimens from 34 patients undergoing carotid endarterectomy were classified according to symptomatic history. Immunostaining combined with digital microscopy revealed greater expression of HN in the unstable plaques of symptomatic compared to asymptomatic patients (29.42±2.05 vs. 14.14±2.13% of plaque area, p<0.0001). These data were further confirmed by immunoblot (density of HN/β-actin standard symptomatic vs. asymptomatic 1.32±0.14 vs. 0.79±0.11, p<0.01). TUNEL staining revealed a higher proportion of apoptotic nuclei in the plaques of symptomatic patients compared to asymptomatic (68.25±3.61 vs. 33.46±4.46% of nuclei, p<0.01). Double immunofluorescence labeling revealed co-localization of HN with macrophages (both M1 and M2 polarization), smooth muscle cells, fibroblasts, and dendritic cells as well as with inflammatory markers MMP2 and MMP9.

CONCLUSIONS

The study demonstrates a higher expression of HN in unstable carotid plaques that is localized to multiple cell types within the plaque. These data support the involvement of HN in atherosclerosis, possibly as an endogenous response to the inflammatory and apoptotic processes within the atheromatous plaque.

The effect of L-arginine or L-citrulline supplementation on biochemical parameters and the vascular aortic wall in high-fat and high-cholesterol-fed rats

The aim of the present study is to investigate the potential role of L-arginine or L-citrulline in rats fed high-fat and high-cholesterol (HFC) diet. HFC feeding increased significantly serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities, urea and all lipid profiles and decreased significantly serum high-density lipoprotein-cholesterol (HDL-c) and non significantly serum nitric oxide levels. L-arginine or L-citrulline administration reversed the increase in serum AST and ALT activities, urea and all lipid profiles. These effects were associated with a concomitant increase in HDL-c and nitric oxide levels. In general, rats fed HFC diet and orally treated with L-arginine or L-citrulline had higher relative percentage of 18:0, 20:0 and 22:6 and lower 16:0 fatty acids than rats fed HFC diet. Light and transmission electron microscopic findings of the thoracic aorta confirmed the biochemical results and demonstrated structural changes in the endothelial cells of the intimal layer, medial smooth muscle cells as well as in the adventitial layer in HFC fed-animals. However, these findings indicate little structural alterations in animals supplemented with L-arginine or L-citrulline along with HFC feeding. In the present study, L-arginine or L-citrulline was effective hypocholesterolemic and hypolipidemic agents in rats.

Studies on antidyslipidemic effects of Morinda citrifolia (Noni) fruit, leaves and root extracts

Background

The objective of present study was to provide the pharmacological basis for the medicinal use of Morinda citrifolia Linn in dyslipidemia using the aqueous-ethanolic extracts of its fruits (Mc.Cr.F), leaves (Mc.Cr.L) and roots (Mc.Cr.R).

Results

Mc.Cr.F, Mc.Cr.L and Mc.Cr.R showed antidyslipidemic effects in both triton (WR-1339) and high fat diet-induced dyslipidemic rat models to variable extents. All three extracts caused reduction in total cholesterol and triglyceride levels in triton-induced dyslipidemia. In high fat diet-induced dyslipidemia all these extracts caused significant reduction in total cholesterol, triglyceride, low density lipoprotein-cholesterol (LDL-C), atherogenic index and TC/HDL ratio. Mc.Cr.R extract also caused increase in high density lipoprotein-cholesterol (HDL-C). The Mc.Cr.L and Mc.Cr.R reduced gain in body weight with a reduction in daily diet consumption but Mc.Cr.F had no effect on body weight and daily diet consumption.

Conclusions

These data indicate that the antidyslipidemic effect of the plant extracts was meditated through the inhibition of biosynthesis, absorption and secretion of lipids. This may be possibly due partly to the presence of antioxidant constituents in this plant. Therefore, this study rationalizes the medicinal use of Morinda citrifolia in dyslipidemia.

Nitric oxide and pathogenic mechanisms involved in the development of vascular diseases

Nitric oxide (NO) is a pivotal signaling messenger in the cardiovascular system. NO participates in regulatory functions including control of hemostasis, fibrinolysis, platelet and leukocyte interactions with the arterial wall, regulation of vascular tone, proliferation of vascular smooth muscle cells, and homeostasis of blood pressure. Diminished NO bioavailability and abnormalities in NO-dependent signaling are among central factors of vascular disease, although it is unclear whether this is a cause of, or result of endothelial dysfunction or both pathogenic events. Disturbances in NO bioavailability have been linked to cause endothelial dysfunction, leading to increased susceptibility to atherosclerotic lesion progression, hypertension, hypercholesterolemia, diabetes mellitus, thrombosis and stroke.

In vivo veritas: Thrombosis mechanisms in animal models

Experimental models have enhanced our understanding of atherothrombosis pathophysiology and have played a major role in the search for adequate therapeutic interventions. Various animal models have been developed to simulate thrombosis and to study in vivo parameters related to hemodynamics and rheology that lead to thrombogenesis. Although no model completely mimics the human condition, much can be learned from existing models about specific biologic processes in disease causation and therapeutic intervention. In general, large animals such as pigs and monkeys have been better suited to study atherosclerosis and arterial and venous thrombosis than smaller species such as rats, rabbits, and dogs. On the other hand, mouse models of arterial and venous thrombosis have attracted increasing interest over the past two decades, owing to direct availability of a growing number of genetically modified mice, improved technical feasibility, standardization of new models of local thrombosis, and low maintenance costs. To simulate rupture of an atherosclerotic plaque, models of arterial thrombosis often involve vascular injury, which can be achieved by several means. There is no animal model that is sufficiently tall, that can mimic the ability of humans to walk upright, and that possesses the calf muscle pump that plays an important role in human venous hemodynamics. A number of spontaneous or genetically engineered animals with overexpression or deletion of various elements in the coagulation, platelet, and fibrinolysis pathways are now available. These animal models can replicate important aspects of thrombosis in humans, and provide a valuable resource in the development of novel concepts of disease mechanisms in human patients.

Albumin resuscitation protects against traumatic/hemorrhagic shock-induced lung apoptosis in rats

OBJECTIVE

To determine the effects of albumin administration on lung injury and apoptosis in traumatic/hemorrhagic shock (T/HS) rats.

METHODS

Studies were performed on an in vivo model of spontaneously breathing rats with induced T/HS; the rats were subjected to femur fracture, ischemia for 30 min, and reperfusion for 20 min with Ringer's lactate solution (RS) or 5% (w/v) albumin (ALB), and the left lower lobes of the lungs were resected.

RESULTS

Albumin administered during reperfusion markedly attenuated injury of the lung and decreased the concentration of lactic acid and the number of in situ TdT-mediated dUTP nick-end labelling (TUNEL)-positive cells. Moreover, immunohistochemistry performed 24 h after reperfusion revealed increases in the level of nuclear factor kappaB (NF-kappaB), and phosphorylated p38 mitogen-activated protein kinase (MAPK) in the albumin-untreated group was down-regulated by albumin treatment when compared with the sham rats.

CONCLUSION

Resuscitation with albumin attenuates tissue injury and inhibits T/HS-induced apoptosis in the lung via the p38 MAPK signal transduction pathway that functions to stimulate the activation of NF-kappaB.

Socioeconomic position and inflammatory and immune biomarkers of cardiovascular disease: applications to the Panel Study of Income Dynamics

Biomarkers are an important aspect of research linking psychosocial stress and health. This article aims to characterize the biological pathways that may mediate the relationship between socioeconomic position (SEP) and cardiovascular disease (CVD) and address opportunities for further research within the Panel Study of Income Dynamics (PSID), with a focus on psychosocial stressors related to SEP. We review the literature on CVD biomarkers, including adhesion and proinflammatory molecules (interleukin-6, other cytokines, C-reactive proteins, fibrinogen, etc.) and microbial pathogens. The impact of socioeconomic determinants and related psychosocial stressors on CVD biomarkers mediated by behavioral and central nervous system pathways are described. We also address measurement and feasibility issues, including specimen collection methods, processing and storage procedures, laboratory error, and within-person variability. In conclusion, we suggest that PSID consider adding important assessments of specific CVD biomarkers and mediating behavioral measures, health, and medications that will ultimately address many of the gaps in the literature regarding the relationship between SEP and cardiovascular health.

Allicin, a major component of garlic, inhibits apoptosis in vital organs in rats with trauma/hemorrhagic shock

OBJECTIVE

Allicin is believed to be the main component responsible for the biological activity of garlic. The regulation of cell apoptosis may have therapeutic potential for trauma/hemorrhagic shock, and previous studies have demonstrated that allicin exerts protective effects against tissue ischemia-reperfusion injury. Therefore, this study examined the effects of allicin on apoptosis-related organ damage, induced by trauma/hemorrhagic shock.

METHODS

Studies were performed on an in vivo model of spontaneously breathing rats with induced trauma/hemorrhagic shock; the left lower lobe of the lungs, left kidney, and intestine were resected, and the rats were subjected to femur fracture, ischemia for 30 mins, and reperfusion for 20 mins. Allicin (30 microg/kg) was administered during reperfusion.

RESULTS

Allicin administered during reperfusion markedly attenuated injury and apoptosis of the lungs, kidneys, and intestine and decreased the concentrations of lactic acid and creatinine, the number of in situ TdT-mediated dUTP nick-end labeling-positive cells, and the activity and expression of caspase-3 and -9 (as determined by Western blot). Furthermore, immunohistochemistry and Western blot performed 24 hrs after reperfusion revealed increases in the levels of nuclear factor kappaB, phosphorylated p38, and extracellular signal-regulated kinase 1 mitogen-activated protein kinase in the allicin-untreated group when compared with the sham rats. Allicin treatment downregulated the levels of nuclear factor kappaB and phosphorylated p38 mitogen-activated protein kinase but did not modify those of phosphorylated extracellular signal-regulated kinase 1 mitogen-activated protein kinase.

CONCLUSION

Allicin attenuates tissue injury and inhibits trauma/hemorrhagic shock- and reperfusion-induced apoptosis in several important organs via the p38 mitogen-activated protein kinase signal transduction pathway that functions to stimulate the activation of nuclear factor-kappaB, caspase-3 and -9, but not of extracellular signal-regulated kinase 1 mitogen-activated protein kinase.

Is there a role for supplemented antioxidants in the prevention of atherosclerosis?

BACKGROUND

Oxidative stress is thought to play a substantial role in the pathogenesis of atherosclerosis. Supplementation of antioxidants has been studied as a strategy in the prevention of occurrence and progression of atherosclerosis.

METHOD

We searched the MEDLINE and PubMed databases (up to February 2008) for randomized, double-blind, placebo-controlled trials of antioxidant (and in particular vitamins E, C and/or beta-carotene) supplementation, published in English.

RESULTS

We identified 22 trials (N=134,590 subjects) of antioxidant supplementation for the prevention of atherosclerosis (7 primary, 13 secondary and 2 both primary and secondary). Of these studies, 10 examined the effect of a single antioxidant supplementation on primary or secondary prevention of cardiovascular disease, while 12 the effect of a combination of antioxidants.

CONCLUSION

As the majority of studies included in this review does not support a possible role of antioxidant supplementation in reducing the risk of cardiovascular disease, no definite conclusion can be drawn to justify the use of antioxidant vitamin supplements for the prevention of atherosclerotic events.

Antihypertensive, antioxidant, antidyslipidemic and endothelial modulating activities of a polyherbal formulation (POL-10)

The present investigation was aimed at providing the pharmacological basis for the medicinal use of a polyherbal formulation (POL-10) in hypertension and dyslipidemia. In spontaneously hypertensive rats, POL-10 significantly (p<0.05) reduced blood pressure to 183.2+/-2.97 vs 198.1+/-5.2 mmHg (Mean+/-S.E.M; n=7-10), improved endothelial dysfunction (p<0.01) by increasing acetylcholine-induced relaxation up to 46.0+/-6.7% vs 24.6+/-3.8% (n=5-10) and decreased serum triglycerides (TG) to 54.5+/-3.3 vs. 93.84+/-5.7 mg/dl (p<0.001). In high fat diet-induced hypercholesterolemia, POL-10 caused reduction in total cholesterol (TC), low density lipoproteins (LDL) levels and the atherogic index (TC-HDL/HDL). It decreased TG levels in tyloxapol-induced hyperlipidemia and increased high-density lipoprotein cholesterol (HDL-C) and reduced atherogenic index in normotensive rats. It exhibited strong antioxidant activity in different in vitro assays. In isolated smooth muscle preparation, POL-10 exhibited calcium channel blocking (CCB) activity by inhibition of high K(+)- induced contractions and rightward shift of Ca(++) concentration-response curves similar to that of verapamil. In conclusion, these findings rationalize the medicinal use of POL-10 in cardiovascular disorders which are mediated through multiple pathways such as, antioxidant, CCB, inhibition of lipid biosynthesis and absorption.

Endothelial nitric oxide (NO) and its pathophysiologic regulation

Nitric oxide (NO) is a gaseous lipophilic free radical generated by three distinct isoforms of nitric oxide synthases (NOS), type 1 or neuronal (nNOS), type 2 or inducible (iNOS) and type 3 or endothelial NOS (eNOS). Expression of eNOS is altered in many types of cardiovascular disease, such as atherosclerosis, diabetes and hypertension. The ubiquitous chaperone heat shock protein 90 (hsp90) associates with NOS and is important for its proper folding and function. Current studies point toward a therapeutic potential by modulating hsp90-NOS association in various vascular diseases. Here we review the transcriptional regulation of endothelial NOS and factors affecting eNOS activity and function, as well as the important vascular pathologies associated with altered NOS function, focusing on the regulatory role of hsp90 and other factors in NO-associated pathogenesis of these diseases.

Microcirculation and oxidative stress

The microcirculation is a complex and integrated system, transporting oxygen and nutrients to the cells. The key component of this system is the endothelium, contributing to the local balance between pro and anti-inflammatory mediators, hemostatic balance, as well as vascular permeability and cell proliferation. A constant shear stress maintains vascular endothelium homeostasis while perturbed shear stress leads to changes in secretion of vasodilator and vasoconstrictor agents. Increased oxidative stress is a major pathogenetic mechanism of endothelial dysfunction by decreasing NO bioavailability, promoting inflammation and participating in activation of intracellular signals cascade, so influencing ion channels activation, signal transduction pathways, cytoskeleton remodelling, intercellular communication and ultimately gene expression. Targeting the microvascular inflammation and oxidative stress is a fascinating approach for novel therapies in order to decrease morbidity and mortality of chronic and acute diseases.

Beneficial effects of low doses of red wine consumption on perturbed shear stress-induced atherogenesis

Moderate wine intake is associated with a reduced risk of morbidity and mortality from cardiovascular disease. Atherosclerosis is enhanced in arterial segments exposed to disturbed flow. Perturbed shear stress increases also the endothelial expression of oxidation-sensitive responsive genes (such as ELK-1 and p-JUN). This study evaluates the effects of chronic consumption of red wine on perturbed shear stress-induced atherogenesis. Results indicated that chronic treatment with red wine significantly attenuated the activation of redox-sensitive genes (ELK-1 and p-JUN) and increased endothelial nitric oxide synthase (eNOS) expression (which was decreased by perturbed shear stress) in cultured human coronary endothelial cells (EC) and in atherosclerosis-prone areas of hypercholesterolemic mice. Oral administration of red wine to hypercholesterolemic mice reduced significantly the progression of atherosclerosis. Moreover, short-term supplementation with red wine to C57BL/6J mice significantly increased upregulation of aortic eNOS and SIRT1 expression induced by physical training. These findings establish that administration of low doses of red wine can attenuate the proatherogenic effects induced by perturbed shear stress in vitro and in vivo. This evidence may have implications for the prevention of atherosclerotic lesion progression and its clinical manifestations.

Shear stress inhibition of H(2)O(2) induced p66(Shc) phosphorylation by ASK1-JNK inactivation in endothelium

Shear stress protects endothelium from a variety of risk factors for vascular disease. Here, we demonstrate a novel mechanism whereby shear stress inhibited reactive oxygen species (ROS)-triggered signaling cascades in endothelial cells. Stimulation of bovine aortic endothelial cells (BAECs) with H(2)O(2) induced a 3.07-fold increase in p66(Shc) phosphorylation. This response was fully blocked by pretreatment of cells with specific JNK but not p38 or ERK MAP kinase inhibitor. Further study showed that knocking down of apoptosis signal-regulating kinase 1 (ASK1) by siRNA transfection in cells dramatically inhibited phosphorylation of JNK and p66(Shc) elicited by H(2)O(2). Pre-perfusion of BAECs cultured in silastic tubes with laminar flow generated by a servo-pump system for 30 min also significantly suppressed H(2)O(2)-induced phosphorylation of p66(Shc). This was accompanied by quantitatively similar inhibition of ASK1 and JNK phosphorylation and activation. These results suggested that shear stress protects endothelium against oxidant stress by suppression of ASK1-JNK-mediated p66(Shc) phosphorylation.

Therapeutic effects of autologous bone marrow cells and metabolic intervention in the ischemic hindlimb of spontaneously hypertensive rats involve reduced cell senescence and CXCR4/Akt/eNOS pathways

Peripheral arterial disease (PAD) is a major health problem, especially when associated with severe hypertension. Administration of autologous bone marrow cells (BMCs) is emerging as a novel intervention to induce neoangiogenesis in ischemic limb models and in patients with PAD. This study evaluates the neovascularization capacity of BMCs alone or in combination with metabolic cotreatment (0.8% vitamin E, 0.05% vitamin C, and 5% of L-arginine) in a rat model of ischemic hindlimbs of spontaneously hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Molecular mechanisms were investigated in bone marrow-derived endothelial progenitor cells (BM-EPC) derived from rats. BMC therapy increased blood flow and capillary densities and Ki67 proliferative marker, and it decreased interstitial fibrosis. These effects were amplified by metabolic cotreatment, an intervention that induces vascular protection at least partly through the nitric oxide (NO)/endothelial nitric oxide synthase (eNOS) pathway, reduction of systemic oxidative stress, and macrophage activation. In addition, BMC therapy alone and, more consistently, in combination with metabolic treatment, ameliorated BM-EPC functional activity via decreased cellular senescence and improved homing capacity by increasing CXCR4-expression levels. These data suggest potential therapeutic effects of autologous BMCs and metabolic treatment in hypertensive PAD patients.

Bone marrow cell-mediated cardiovascular repair: potential of combined therapies

Recent evidence indicates that bone-marrow cells (BMCs) can contribute to the healing process of the injured cardiovascular system via the chemokine receptor CXCR4/SDF-1, thymosin beta(4) and integrin alpha(4)beta(1) molecular pathways. During tissue ischemia overwhelming numbers of detrimental oxygen radicals are generated, and therefore treatment with antioxidants and L-arginine, the precursor of nitric oxide (NO), could induce beneficial effects beyond those achieved by BMC transplantation alone. Recent studies have reported that BMCs have enhanced neovascularization capacity in cotreatment with alpha-tocopherol (vitamin E), ascorbic acid (vitamin C) and L-arginine. Moreover, BMC therapy can be combined with gene therapy. Clinical trials employing BMCs in the treatment of cardiovascular diseases have been completed with mixed or positive results, and several trials are ongoing. Here, we discuss the clinical potential of BMC transplantation alone and in combined therapy that aims to restore organ vascularization and function. We also consider the mechanisms of mobilization, differentiation and incorporation of BMCs.

Role of asymmetric dimethylarginine in homocysteine-induced apoptosis of vascular smooth muscle cells

Homocysteine (Hcy) could induce apoptosis of vascular smooth muscle cells (VSMC). Asymmetric dimethylarginine (ADMA) has been thought as a novel risk factor for cardiovascular diseases. We hypothesized that ADMA mediates homocysteine-induced apoptosis of VSMC. In this experiment the level of ADMA in the medium measured by high-performance liquid chromatography (HPLC) was elevated when the apoptosis of T/G HA-VSMC was induced by Hcy which was detected by Hoechst33342 staining or flow cytometry (FCM) with Annecin V+Propidium Iodide (PI). Exogenous ADMA induced the apoptosis of VSMC. At the same time, ADMA elevated the level of intracellular reactive oxidative species (ROS) determined by fluorescent ROS detection kit. The activation of JNK and p38MAPK contributed to ADMA-induced apoptosis of VSMC. The present results suggest that endogenous ADMA is involved in apoptosis of VSMC induced by Hcy, and the effects of ADMA is related to elevation of intracellular ROS and activation of JNK/p38MAPK signaling pathways.

Circulating Apoptotic Progenitor Cells

BACKGROUND

Progenitor CD34 cells are capable of differentiating into endothelial cells and play a role in neoangiogenesis. Circulating CD34+ cells and endothelial progenitor cells are increased in acute coronary syndrome (ACS) patients possibly because of peripheral mobilization. We tested the hypothesis that circulating apoptotic progenitors are detectable in healthy subjects and altered in ACS patients.

METHODS AND RESULTS

Peripheral blood mononuclear cells were isolated by Ficoll density gradient from 53 patients with ACS undergoing coronary angiography and 27 healthy subjects. Apoptosis in progenitor CD34+ cells was assessed using the Annexin V-PE/7-AAD detection kit, and fluorescence-activated cell sorter analysis was performed with triple staining for CD34, annexin-V, and 7-AAD. The percentage of apoptotic CD34+ progenitors was determined in the 2 subject groups and correlated with clinical characteristics. The percentage of apoptotic CD34+ progenitor cells was significantly increased in patients with ACS as compared with healthy subjects and was associated with the extent of coronary stenosis by angiography. There was no significant correlation between apoptotic progenitor CD34+ cells and the other parameters that we examined (age, smoking, hypertension, hyperlipidemia, diabetes mellitus, ejection fraction, creatinine levels, or taking any of the various medications, including beta blockers, thiazides, angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, calcium blockers, nitrates, or statins).

CONCLUSION

We established for the first time to our knowledge an assay to detect circulating apoptotic progenitor cells using fluorescein isothiocyanate-anti-CD34 MAb, annexin V-PE, and 7-AAD and found that apoptotic CD34+ cells are increased in ACS patients and in patients with more extensive coronary artery disease. This novel assay may shed new light on the factors governing the hemostasis of progenitor CD34+ cells.

Pomegranate juice reduces oxidized low-density lipoprotein downregulation of endothelial nitric oxide synthase in human coronary endothelial cells

We examined the hypothesis that pomegranate juice (PJ) can revert the potent downregulation of the expression of endothelial nitric-oxide synthase (NOSIII) induced by oxidized low-density liporotein (oxLDL) in human coronary endothelial cells. Western blot and Northern blot analyses showed a significant decrease of NOSIII expression after a 24-h treatment with oxLDL. Accordingly, we observed a significant dose-dependent reduction in nitric oxide bioactivity represented by both basal and bradykinin-stimulated cellular cGMP accumulation. These phenomena were corrected significantly by the concomitant treatment with PJ. Our data suggest that PJ can exert beneficial effects on the evolution of clinical vascular complications, coronary heart disease, and atherogenesis in humans by enhancing the NOSIII bioactivity.

Asymmetrical dimethylarginine regulates endothelial function in methionine-induced but not in chronic homocystinemia in humans: effect of oxidative stress and proinflammatory cytokines

BACKGROUND

Homocystinemia is a metabolic abnormality associated with endothelial dysfunction and increased cardiovascular disease risk. The underlying mechanisms of these effects, however, are obscure.

OBJECTIVE

We examined the effect of asymmetrical dimethylarginine (ADMA) on endothelial dysfunction in methionine-induced and chronic homocystinemia and evaluated the regulatory role of oxidative stress and proinflammatory cytokines on the release of ADMA.

DESIGN

In this double-blind, placebo-controlled parallel group study, 30 subjects of both sexes (15 with homocystinemia and 15 healthy controls) underwent methionine loading, with simultaneous administration of a combination of vitamin C (2 g) plus alpha-tocopherol (800 IU) or placebo. Endothelial function in forearm resistance vessels and concentrations of ADMA, oxidized LDL, and proinflammatory cytokines were determined at baseline and 4 h after methionine loading.

RESULTS

Both chronic and methionine-induced homocystinemia were associated with increased oxidized LDL (P < 0.01), higher expression of the proinflammatory cytokine interleukin 6 (P < 0.05), and endothelial dysfunction (P < 0.01). Although ADMA rapidly increased in acute homocystinemia (P < 0.01) and was correlated with forearm hyperemic response at 4 h after methionine loading (r = -0.722, P = 0.0001), it was not higher in subjects with high versus low fasting homocysteine. High-dose antioxidant treatment prevented methionine-induced elevation of oxidized LDL and interleukin 6 but failed to prevent the increase in ADMA or endothelial dysfunction.

CONCLUSIONS

Both chronic and methionine-induced homocystinemia are characterized by increased oxidative stress and proinflammatory cytokines, which may contribute to the development of endothelial dysfunction. However, the ADMA pathway is activated only in acute homocystinemia by mechanisms not mediated by oxidized LDL or proinflammatory stimuli.

Pomegranate juice protects nitric oxide against oxidative destruction and enhances the biological actions of nitric oxide

Pomegranate juice (PJ), which is a rich source of potent flavonoid antioxidants, was tested for its capacity to protect nitric oxide (NO) against oxidative destruction and enhance the biological actions of NO. Employing chemiluminescence headspace analysis, PJ was found to be a potent inhibitor of superoxide anion-mediated disappearance of NO. PJ was much more potent than Concord grape juice, blueberry juice, red wine, ascorbic acid, and DL-alpha-tocopherol. As little as 3 microl of a 6-fold dilution of PJ, in a reaction volume of 5000 microl, produced a marked antioxidant effect, whereas 300 microl of undiluted blueberry juice or nearly 1000 microl of undiluted Concord grape juice were required to produce similar effects. PJ and other antioxidant-containing products were found to augment the anti-proliferative action of NO (DETA/NO) on vascular smooth muscle cell (rat aorta) proliferation. PJ was much more effective than the other products tested and elicited no effects when tested alone in the absence of added NO. Similarly, neither PJ nor the other products enhanced the anti-proliferative action of alpha-difluoromethylornithine, a stable substance that inhibits cell growth by NO-independent mechanisms. In order to determine whether PJ is capable of increasing the production of NO by vascular endothelial cells, PJ was tested for its capacity to upregulate and/or activate endothelial NO synthase (eNOS) in bovine pulmonary artery endothelial cells. PJ elicited no effects on eNOS protein expression or catalytic activity. Moreover, PJ did not enhance promoter activity in the eNOS gene (COS-7 cells transfected with eNOS). These observations indicate that PJ possesses potent antioxidant activity that results in marked protection of NO against oxidative destruction, thereby resulting in augmentation of the biological actions of NO.

Therapeutic effects of concurrent autologous bone marrow cell infusion and metabolic intervention in ischemia-induced angiogenesis in the hypercholesterolemic mouse hindlimb

Lower-limb ischemia is a major health problem especially when associated to hypercholesterolemia. Because of the absence of effective treatment in the advanced stages of the disease, amputation is undertaken to alleviate unbearable symptoms. Since tissue ischemia and hypercholesterolemia are associated with an overwhelming generation of oxygen radicals, metabolic intervention with antioxidants and l-arginine can induce beneficial effects beyond those achieved by a novel therapeutic approach represented by the use of autologous bone marrow cells (BMCs). The protective effect of BMCs and vascular protection by metabolic cotreatment (1.0% vitamin E added to the chow, 0.05% vitamin C and 6% l-arginine added to the drinking water) were examined in ischemia-induced angiogenesis in the hypercholesterolemic mouse hindlimb. Intravenous BMC therapy improved blood flow and increased capillary densities. This beneficial effect was amplified by metabolic cotreatment, an intervention inducing vascular protection, at least in part, through the nitric oxide pathway, reduction of systemic oxidative stress and macrophage activation.

Inhibitory effect of Magnolia officinalis and lovastatin on aortic oxidative stress and apoptosis in hyperlipidemic rabbits

Oxidative stress and apoptosis are 2 major characteristics of the progression of atherosclerosis. Both lovastatin and Magnolia officinalis are hypocholesterolemic agents. Therefore, we investigated the effect of M. officinalis extract on the prevention of atherosclerosis in comparison with lovastatin. Twenty hyperlipidemic rabbits were served one of the following diets: a high-fat and cholesterol diet (cholesterol group, 10% corn oil and 0.5% cholesterol), a high fat and cholesterol diet supplemented with M. officinalis extract (300 mg/kg) or lovastatin (6 mg/kg). The plasma lipids, oxidative stress (measured by free radical, malondialdehyde, and oxidative DNA damage), and arterial lesions significantly decreased in the M. officinalis and lovastatin groups when compared with the cholesterol group. Moreover, the expressions of Fas ligand, caspase 8, and caspase 9 in the aortic arches were also markedly lowered after M. officinalis and lovastatin supplements. Therefore, the results indicate that the antiatherogenic effect of M. officinalis is involved with a suppression of oxidative stress and with the down-regulation of apoptosis-related gene expression in hyperlipidemic rabbits.