Increased nitrate intake from beetroot juice over 4 weeks affects nitrate metabolism, but not vascular function or blood pressure in older adults with hypertension.

The decline in vascular function and increase in blood pressure with aging contribute to an increased cardiovascular disease risk. In this randomized placebo-controlled crossover study, we evaluated whether previously reported cardiovascular benefits of plant-derived inorganic nitrate via nitric oxide (NO) translate into improved vascular function and blood pressure-lowering in 15 men and women (age range: 56-71 years) with treated hypertension. We investigated the effects of a single ∼400 mg-dose at 3 hours post-ingestion (3H POST) and the daily consumption of 2 × âˆ¼400 mg of nitrate through nitrate-rich compared with nitrate-depleted (placebo) beetroot juice over 4 weeks (4WK POST). Measurements included nitrate and nitrite in plasma and saliva; endothelial-dependent and -independent forearm blood flow (FBF) responses to acetylcholine (FBFACh) and glyceryltrinitrate (FBFGTN); and clinic-, home- and 24-hour ambulatory blood pressure. Compared to placebo, plasma and salivary nitrate and nitrite increased at 3H and 4WK POST following nitrate treatment (P < 0.01), suggesting a functioning nitrate-nitrite-NO pathway in the participants of this study. There were no differences between treatments in FBFACh and FBFGTN-area under the curve (AUC) ratios [AUC ratios after (3H POST, 4WK POST) compared with before (PRE) the intervention], or 24-hour ambulatory blood pressure or home blood pressure measures (P > 0.05). These findings do not support the hypothesis that an increased intake of dietary nitrate exerts sustained beneficial effects on FBF or blood pressure in hypertensive older adults, providing important information on the efficacy of nitrate-based interventions for healthy vascular aging. This study was registered under ClinicialTrials.gov (NCT04584372).

Cardiovascular risk and mortality in patients with hyperuricemia treated with febuxostat or allopurinol: a retrospective nation-wide cohort study in Austria 2014-2017.

Patients with hyperuricemia and gout are at an increased risk for cardiovascular (CV) disease. Inhibition of the xanthine oxidase with allopurinol or febuxostat have become the mainstay for urate lowering therapy. However, it has been suggested that febuxostat increases the risk for CV mortality as compared to allopurinol. The aim of this retrospective cohort study was to assess the CV risk among patients with febuxostat or allopurinol therapy. Patients who initiated urate lowering therapy with febuxostat or allopurinol between 2014 and 2017 were selected from the drug reimbursement database of the Austrian health insurances funds. The primary CV endpoint was a composite of angina pectoris, nonfatal myocardial infarction, nonfatal subarachnoid or cerebral hemorrhage, nonfatal ischemic stroke, or death from any cause. In total, 28.068 patients (62.1% male) with a mean age of 71 years were included. 7.767 initiated febuxostat treatment and 20.301 received allopurinol. The incidence rate per 100 patient-years of the composite primary endpoint was 448 (febuxostat) and 356 (allopurinol) with a corresponding adjusted hazard ratio (HR) of 0.58 (95% CI 0.53-0.63) for allopurinol vs. febuxostat initiators. Similar HR were found for secondary endpoints including all-cause mortality [0.61 (95% CI 0.55-0.68)] and separate analyses of cardiac events [0.48 (95% CI 0.38-0.61)] and ischemic stroke [0.47 (95% CI 0.36-0.61)]. Data from this Austrian population-based study suggests that febuxostat initiators are at an increased risk for nonfatal CV events or death from any cause as compared to those with allopurinol. This is consistent with CV concerns of other trials, which limited the broad therapeutic use of febuxostat.

Dose-dependent naloxone-induced morphine withdrawal symptoms in opioid-dependent males-a double-blinded, randomized study.

AIMS: Oral opioid preparations combined with naloxone are intended to induce a transient acute withdrawal syndrome to avoid intravenous misuse. This trial aimed to establish an appropriate morphine-naloxone dose ratio for an abuse-deterrent oral opioid formulation. METHODS: In a randomized, double-blinded, 2 × 2 cross-over trial, 43 patients with opioid use disorder were challenged with intravenous morphine HCl Ph.Eur. (75 mg; [morphine mono]) or morphine HCl Ph.Eur. and naloxone HCl Ph.Eur. at ratios of 100:1 (75 mg: 0.75 mg; [morphine-naloxone 100:1]) or 200:1 (75 mg: 0.375 mg; [morphine-naloxone 200:1]). Acute naloxone-induced opioid withdrawal was evaluated using subjective (Short Opiate Withdrawal Scale-German [SOWS-G]) and observer-rated (Objective Opiate Withdrawal Scale [OOWS], Wang scale) questionnaires, and physiological parameters. For statistical analysis, the area under the curve between baseline and 20 minutes after drug administration of the outcome variables was calculated. RESULTS: Intravenous morphine-naloxone caused rapid withdrawal symptoms. Coadministration of naloxone dose-dependently (morphine-naloxone 100:1 > morphine-naloxone 200:1) increased SOWS-G, OOWS and Wang Scale area under the curve when compared to morphine mono, respectively (all P < .0001). A similar response was detectable for changes of pupil diameter. Blood pressure and respiratory rate changed heterogeneously, and heart rate was unaltered by morphine without or with naloxone. CONCLUSION: Morphine-naloxone 100:1 effectively suppresses the pleasurable effects of intravenous morphine and results in an aversive withdrawal reaction. A lower naloxone concentration as used in morphine-naloxone 200:1 does not appear to be appropriate to prevent intravenous morphine misuse.

ADMA and NT pro-BNP are associated with overall mortality in elderly.

BACKGROUND: Increased asymmetrical dimethylarginine (ADMA) and NT pro-BNP concentrations have been associated with mortality in patients with cardiovascular (CV) disease and the general population. The use of these prognostic markers in an older population is not established yet. The aim of the present study was to investigate the prognostic value of age, sex, BMI, co-medication and CV laboratory risk markers in geriatric care patients. MATERIALS AND METHODS: In this prospective observational single-centre cohort study data of long-term geriatric care patients were collected. Blood samples were collected between 14.09.2009 and 16.12.2009, and mortality was recorded up to 90 months. ADMA, its symmetric isomer SDMA, L-arginine, NT pro-BNP and CRP were determined at study entry. Simple associations of risk factors for survival period were explored by Spearman correlation coefficient. Significant univariate predictors for survival period were used in the Cox proportional hazard model. RESULTS: A total of 481 patients were screened, and data from 449 patients were analysed. A total of 381 patients died during the observation period. Full data sets from 344 patients were used for Cox regression analysis. Male sex, older age, lower BMI, use of neuroleptic medicine, peripheral artery disease, and elevated plasma concentrations of ADMA, NT pro-BNP, and CRP were significant predictors of mortality. CONCLUSION: The concentration of ADMA and NT pro-BNP may be used as an early risk marker for overall mortality in geriatric care. Neuroleptic medicine is associated with increased mortality in this population.

Vaccines Targeting PCSK9: A Promising Alternative to Passive Immunization with Monoclonal Antibodies in the Management of Hyperlipidaemia?

Hypercholesterolaemia is frequently observed in patients with cardiovascular diseases (CVD) and is associated with increased mortality. Statin treatment has been the standard of care for reducing low-density lipoprotein cholesterol (LDL-C) to improve cardiovascular outcomes. However, statins have limited effects in some patients and may be discontinued due to adverse effects resulting in LDL-C above target levels. The proprotein convertase subtilisin kexin type 9 (PCSK9) is a pivotal regulator in the LDL-C metabolism by degrading the LDL-C receptor on hepatocytes. Inhibition of PCSK9 by monoclonal antibodies (mAb) significantly lowers LDL-C levels and is considered to reduce the likelihood of adverse cardiac events. However, such treatment regimens are not cost-effective, and require frequent administrations at high doses that may be associated with side effects and poor drug adherence. Furthermore, it has been shown that these PCSK9 medicines may trigger the formation of antidrug antibodies followed by a significant attenuation of the LDL-C-lowering effect. Active vaccination inducing high-affinity antibodies against PCSK9 with less frequent administration intervals may be a novel promising therapeutic approach to overcome the drawback of passive immunization with PCSK9 mAb. However there is a paucity of available clinical safety and efficacy data. This article discusses challenges in the development of PCSK9 vaccines and their potential therapeutic benefits by reviewing clinical studies that evaluated the safety and efficacy of PCSK9 mAb.

Atorvastatin combined with ticagrelor prevent ischemia-reperfusion induced vascular endothelial dysfunction in healthy young males - A randomized, placebo-controlled, double-blinded study.

BACKGROUND: Atorvastatin and ticagrelor have been shown to prevent against tissue injury in animals. It is unclear if these beneficial effects are also detectable in humans. We studied the effect of high-dose atorvastatin combined with ticagrelor loading on endothelial dysfunction in a model of forearm vascular ischemia-reperfusion (IR) injury. METHODS: 32 healthy subjects (n=16 per group) were enrolled in this randomized, placebo-controlled, double-blinded trial. Forearm blood flow (FBF) measurements in response to increasing intra-arterial doses of the vasodilator acetylcholine (ACh; endothelium-dependent agonist) and glyceryltrinitrate (GTN; endothelium-independent) were performed before and after a cuff-induced 20min forearm ischemia, respectively. FBF reactivity was assessed prior to any pharmacological intervention and after 14days intake of 80mg atorvastatin once daily or placebo, followed by an oral loading dose of 180mg ticagrelor. In addition, lipoprotein parameters and platelet aggregation were evaluated. RESULTS: Ticagrelor loading mitigated ischemia-induced endothelial dysfunction and in combination with repeated atorvastatin dosing the response to ACh during reperfusion was completely normalized (FBF AChAUC ratio post- vs. pre-ischemia: 0.81 [ticagrelor] vs. 1.04 [atorvastatin+ticagrelor]; P=0.001). As expected, GTN-induced vasodilation was not affected by IR injury. Atorvastatin significantly reduced total and low density lipoprotein cholesterol concentrations, while high density lipoprotein cholesterol and triglyceride levels remained unchanged. CONCLUSION: Chronic atorvastatin treatment combined with ticagrelor loading prevents against endothelial dysfunction after acute forearm ischemia. Ticagrelor alone mitigated the impaired endothelium-dependent FBF response as compared to no pharmacological intervention. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov. Unique identifier: NCT02910778.

Ticagrelor mitigates ischaemia-reperfusion induced vascular endothelial dysfunction in healthy young males - a randomized, single-blinded study.

AIMS: Animal data suggest that ticagrelor but not clopidogrel protects against tissue injury. It is unclear if this effect of ticagrelor is also detectable in humans. We studied the effect of ticagrelor and clopidogrel at standard clinical doses on endothelial dysfunction in an experimental model of forearm vascular ischaemia-reperfusion (IR) injury. METHODS: In a randomized, single-blinded trial, 24 subjects underwent forearm blood flow (FBF) measurements in response to the endothelium-dependent vasodilator acetylcholine (ACh) and to glyceryltrinitrate (GTN; endothelium-independent) before and after a 20 min forearm ischaemia. FBF reactivity was assessed after an oral loading dose of ticagrelor or clopidogrel and after 14 days of regular intake of maintenance doses of the study medicines. In addition, the effect on platelet inhibition was evaluated using multiple electrode aggregometry. RESULTS: ACh-induced vasodilation was impaired during reperfusion and not completely normalized by acute or chronic treatment with ticagrelor or clopidogrel (post- vs. pre-ischaemia). However, ticagrelor mitigated endothelial dysfunction compared to clopidogrel after loading (FBF AChAUC ratio post- vs. pre-ischaemia: 0.83 [0.70; 0.96] vs. 0.64 [0.56; 0.72]; P = 0.024) and after chronic administration (FBF AChAUC ratio: 0.86 [0.71; 1.00] vs. 0.66 [0.55; 0.77]; P = 0.027). As expected, GTN-induced vasodilation was not affected by ischaemia. Ticagrelor or clopidogrel treatment inhibited platelet activation to a similar degree. CONCLUSION: Our data indicate that ticagrelor treatment exerts a greater vascular salutary effect than clopidogrel during reperfusion after an acute vascular occlusion. IR-induced vascular injury cannot be prevented completely by administration of these antiplatelet agents at standard clinical doses.

The effect of a dual or a triple antithrombotic therapy with apixaban on thrombus formation in vivo and in an ex vivo perfusion chamber model: An open-label, controlled, sequential study.

BACKGROUND: There is a need to optimize pharmacological treatment in patients with acute coronary syndrome and concomitant atrial fibrillation, in particular with newer antithrombotic medicines. We have therefore studied if dual or triple combination of antithrombotic agents exert similar effects on coagulation activation in an in vivo model in the skin microvasculature and in an ex vivo perfusion chamber. METHODS AND RESULTS: Shed blood platelet activation (ß-thromboglobulin [ß-TG]), thrombin generation (thrombin-antithrombin complex [TAT]) and volume as well as markers of thrombus size (D-dimer) and its platelet content (P-selectin) in a perfusion chamber were studied in a sequential, open-label, parallel group trial in 40 healthy male volunteers (n = 20 per group). Subjects received ticagrelor and apixaban without or with acetylsalicylic acid (ASA). Outcome parameters were assessed at 3 hours after therapy dosing, and at steady-state trough and peak conditions.A triple or dual therapy induced a comparable decrease in shed blood ß-TG at 3 hours after therapy dosing but was more pronounced at steady-state conditions with the more intense treatment combination. During both antithrombotic regimens a similarly sustained inhibition in thrombin generation was observed which was accompanied by comparable increases in shed blood volume. In contrast, no treatment effect could be observed in the perfusion chamber experiment. CONCLUSION: Ticagrelor and apixaban with or without ASA inhibit platelet activation and thrombin formation in vivo in healthy subjects. Platelet inhibition was greater at steady-state conditions after triple therapy administration.

Safety, tolerability and pharmacokinetics of liposomal curcumin in healthy humans.

INTRODUCTION: Experimental studies have shown that liposomal curcumin can exert a reduction in tumor growth in pancreatic and colorectal cancer. In this phase I clinical trial we investigated the pharmacokinetics, safety, and tolerability of intravenously administered liposomal curcumin in healthy subjects. MATERIAL AND METHODS: 50 male and female participants were included in this randomized, placebo-controlled double-blind phase I dose escalation study. Subjects received a single dose of liposomal curcumin (10 - 400 mg/m2; n = 2 - 6 per group) or placebo over 2 hours intravenously. RESULTS: Dose-dependent increases in the plasma concentrations of curcumin and its metabolite tetrahydrocurcumin (THC) were detected. After the end of drug infusion, curcumin and THC plasma concentrations decreased within 6 - 60 minutes below the limit of quantification. Mean urinary excretion was ~ 0.1% of total systemic clearance. Liposomal curcumin was tolerated well, but a transient red blood cell echinocyte formation with concomitant increase in mean cellular volume was observed at dosages ≥ 120 mg/m2. CONCLUSION: Short-term intravenous dosing of liposomal curcumin appears to be safe up to a dose of 120 mg/m2. Changes in red blood cell morphology may represent a dose limiting sign of toxicity.

Human pharmacokinetics of high dose oral curcumin and its effect on heme oxygenase-1 expression in healthy male subjects.

PURPOSE: Heme oxygenase-1 (HO-1) has been proposed to exert pharmacological benefits by its antioxidative and anti-inflammatory effects. HO-1 expression may be affected by the GT length polymorphism in the promoter region of the HO-1 gene. We investigated the inducibility of HO-1 by orally administered curcumin in healthy male subjects and its correlation with the GT length polymorphism. METHODS: In an open label uncontrolled phase-1 pilot study, ten male subjects received 12 g of oral curcumin. To investigate the effects of the GT length polymorphism on the inducibility of HO-1, five subjects with homozygous short and five with homozygous long GT genotypes were studied. Plasma concentrations of curcumin, bilirubin, HO-1 mRNA, and protein expression in peripheral blood mononuclear cells (PBMCs) were analyzed over 48 hours. RESULTS: At a detection limit of 1 µg/mL curcumin could not be detected in plasma of any subject. Compared to baseline, HO-1 mRNA and protein levels were not induced in PBMCs at any time point up to 48 hours. There was no correlation between any of the parameters and GT length polymorphism. CONCLUSIONS: Oral curcumin administration has low bioavailability and does not induce HO-1 on mRNA or protein level in PBMCs.

Effect of liposomal curcumin on red blood cells in vitro.

BACKGROUND: The anti-inflammatory and antiproliferative agent curcumin has poor oral bioavailability and solubility in plasma. Liposomal formulations have therefore been developed, but the toxicity of these preparations is not yet established. We investigated the influence of free and liposomally formulated curcumin on human red blood cell (RBC) morphology in vitro. MATERIALS AND METHODS: EDTA-buffered whole blood from two healthy individuals was incubated with different concentrations (1, 10, 100 µg/ml) of free or liposomal curcumin. RBC morphology and mean cellular volume (MCV) were examined at up to 4 hours of incubation. RESULTS: Dose-dependent echinocyte formation was observed after incubation with free, and liposomal curcumin, with a threshold concentration of 10 µg/ml and peak effect after 30 minutes. A concomitant increase in mean cellular volume was detectable. CONCLUSION: Curcumin and liposomal curcumin cause dose-dependent changes in the shape of RBCs. This effect may represent an early sign of dose-limiting toxicity following intravenous administration.

The LPS-induced increase in circulating microparticles is not affected by vitamin C in humans.

OBJECTIVE: Microparticles (MP) are considered to promote coagulation. This study aimed to characterize the time course of MP levels and the effect of high-dose vitamin C on MP formation during inflammation in an in vivo Escherichia coli endotoxin (LPS) model. METHODS: Microparticle formation was studied in 14 male subjects in a cross-over trial who received either intravenous vitamin C at 320 mg/kg body weight (BW) or 480 mg/kg BW or saline solution in a random order on alternate trial days 3 h after intravenous exposure to LPS (2 ng/kg BW). Venous blood samples were taken before, 3 and 6 h after LPS. D-dimer, leucocyte count, C-reactive protein, plasma vitamin C and body temperature were assessed as inflammatory parameters. MP were detected using flow cytometric analysis and expressed in 10³ MP/mL plasma. RESULTS: Microparticles levels were decreased from baseline 848 units [range 431-1705] by 21% to 671 units [253-1586] at 3 h and increased by 32% to 1119 units [288-4443] at 6 h after LPS. This pattern was not influenced by administration of vitamin C, with a change from 730 units [399-1396] at baseline by an increase to 832 units [215-2168] at 3 h to 1055 units [350-4858] at 6 h. MP subpopulations followed similar dynamics. Alterations in inflammatory parameters were independent from vitamin C administration during endotoxemia. CONCLUSION: Microparticles are increased in acute systemic inflammation with inconsistent changes in MP subgroups in healthy subjects. Systemic vitamin C administration does not mitigate MP formation and D-dimer levels during acute systemic inflammation, suggesting that MP-induced coagulation activity is not affected by vitamin C.

Heme arginate improves reperfusion patterns after ischemia: a randomized, placebo-controlled trial in healthy male subjects.

BACKGROUND: Heme arginate can induce heme oxygenase-1 to protect tissue against ischemia-reperfusion injury. Blood oxygen level dependent (BOLD) functional magnetic resonance imaging measures changes in tissue oxygenation with a high spatial and temporal resolution. BOLD imaging was applied to test the effect of heme arginate on experimental ischemia reperfusion injury in the calf muscles. METHODS: A two period, controlled, observer blinded, crossover trial was performed in 12 healthy male subjects. Heme arginate (1 mg/kg body weight) or placebo were infused 24 h prior to a 20 min leg ischemia induced by a thigh cuff. 3 Tesla BOLD-imaging of the calf was performed and signal time courses from soleus, gastrocnemius and tibialis anterior muscle were available from 11 participants for technical reasons. RESULTS: Peak reactive hyperemia signal of the musculature was significantly increased and occurred earlier after heme arginate compared to placebo (106.2 ± 0.6% at 175 ± 16s vs. 104.5 ± 0.6% at 221 ± 19s; p = 0.025 for peak reperfusion and p = 0.012 for time to peak). CONCLUSIONS: A single high dose of heme arginate improves reperfusion patterns during ischemia reperfusion injury in humans. BOLD sensitive, functional MRI is applicable for the assessment of experimental ischemia reperfusion injury in skeletal muscle.

Analysis of cellular SUMO and SUMO-ubiquitin hybrid conjugates.

Posttranslational modification of proteins with the small ubiquitin-related modifier (SUMO) has been implicated in many important physiological functions, including the regulation of transcription and DNA repair. In most cases, only a small fraction of the total cellular amounts of a given protein is sumoylated at a certain point in time. Sensitive detection of sumoylated forms of proteins by western blotting is, therefore, an important step in the identification and/or characterization of a protein control by sumoylation. Polysumoylated proteins are recognized and targeted to the proteasome by specific ubiquitin ligases bearing SUMO interaction motifs. Sumoylation itself is reversible by the action of desumoylating enzymes. Their activities cause a rapid loss of SUMO conjugates in most standard cell extracts. To preserve SUMO-protein conjugates, therefore, a preparation of extracts under denaturing conditions is recommended. Here, we describe the application of an alkaline lysis procedure and a western blot protocol for the analysis of SUMO conjugates in yeast and human cells. In addition, we describe the application of another extraction procedure combined with immobilized metal affinity chromatography for the analysis of ubiquitin-SUMO hybrid conjugates from yeast and human cells.

Arsenic trioxide stimulates SUMO-2/3 modification leading to RNF4-dependent proteolytic targeting of PML.

We have recently reported that poly-SUMO-2/3 conjugates are subject to a ubiquitin-dependent proteolytic control in human cells. Here we show that arsenic trioxide (ATO) increases SUMO-2/3 modification of promyelocytic leukemia (PML) leading to its subsequent ubiquitylation in vivo. The SUMO-binding ubiquitin ligase RNF4 mediates this modification and causes disruption of PML nuclear bodies upon treatment with ATO. Reconstitution of SUMO-dependent ubiquitylation of PML by RNF4 in vitro and in a yeast trans vivo system revealed a preference of RNF4 for chain forming SUMOs. Polysumoylation of PML in response to ATO thus leads to its recognition and ubiquitylation by RNF4.

Ubiquitin-dependent proteolytic control of SUMO conjugates.

Posttranslational protein modification with small ubiquitin-related modifier (SUMO) is an important regulatory mechanism implicated in many cellular processes, including several of biomedical relevance. We report that inhibition of the proteasome leads to accumulation of proteins that are simultaneously conjugated to both SUMO and ubiquitin in yeast and in human cells. A similar accumulation of such conjugates was detected in Saccharomyces cerevisiae ubc4 ubc5 cells as well as in mutants lacking two RING finger proteins, Ris1 and Hex3/Slx5-Slx8, that bind to SUMO as well as to the ubiquitin-conjugating enzyme Ubc4. In vitro, Hex3-Slx8 complexes promote Ubc4-dependent ubiquitylation. Together these data identify a previously unrecognized pathway that mediates the proteolytic down-regulation of sumoylated proteins. Formation of substrate-linked SUMO chains promotes targeting of SUMO-modified substrates for ubiquitin-mediated proteolysis. Genetic and biochemical evidence indicates that SUMO conjugation can ultimately lead to inactivation of sumoylated substrates by polysumoylation and/or ubiquitin-dependent degradation. Simultaneous inhibition of both mechanisms leads to severe phenotypic defects.