Enriched stable 204Pb as tracer at ultra-low levels in clinical investigations.

The potential of enriched Pb (204Pb) was assessed to monitor pathways of trace levels of Pb in the pg range within the human body via isotope pattern variation in situations where natural lead cannot be used as a tracer due to regulatory limitations. Isotope ratio measurements were accomplished by means of (multi-collector) inductively coupled plasma mass spectrometry including a comparison of single and multi-collector ICP-MS for low-level 204Pb assessment. Isotopic pattern results from a blend of a large quantity of the element with a natural isotopic composition and an enriched stable isotope at orders of magnitude lower levels pose a nontrivial analytical problem. Isotope pattern deconvolution was successfully applied as mathematical tool based on multiple linear regressions. The method allowed for deconvolving the isotope pattern from measured isotope ratios without knowing the quantities of different isotope sources incorporated and mixed into the sample at levels of < 1 pg 204Pb/g blood. The objective of this manuscript is to evaluate and summarize the analytical aspects for Pb isotope pattern deconvolution based on the results of a clinical trial, where a 204Pb-enriched isotope tracer was applied to investigate the bioavailability of orally applied Pb along with purified clinoptilolite tuff as potential supplement. This unique approach allows to reduce tracer amounts to harmless levels to human health, which are in accordance with the legal regulative to study enrichment levels of < 0.01% in human blood.

Safety and efficacy of purified clinoptilolite-tuff treatment in patients with irritable bowel syndrome with diarrhea: Randomized controlled trial.

BACKGROUND: Irritable bowel syndrome (IBS) is a highly prevalent gastrointestinal disorder with poor response to treatment. IBS with predominant diarrhea (IBS-D) is accompanied by abdominal pain as well as high stool frequency and urgency. Purified clinoptilolite-tuff (PCT), which is approved by the Food and Drug Administration for use as a dietary supplement with the brand name G-PUR®, has previously shown therapeutic potential in other indications based on its physical adsorption capacity. AIM: To assess whether symptoms of IBS-D can be ameliorated by oral treatment with PCT. METHODS: In this randomized, placebo-controlled, double-blind pilot study, 30 patients with IBS-D diagnosis based on Rome IV criteria were enrolled. Following a 4-wk run-in phase, 14 patients were randomized to receive a 12-wk treatment with G-PUR® (2 g three times daily), and 16 patients received placebo. The relief from IBS-D symptoms as measured by the proportion of responders according to the Subject's Global Assessment (SGA) of Relief was assessed as the primary outcome. For the secondary outcomes, validated IBS-D associated symptom questionnaires, exploratory biomarkers and microbiome data were collected. RESULTS: The proportions of SGA of Relief responders after 12 wk were comparable in both groups, namely 21% in the G-PUR® group and 25% in the placebo group. After 4 wk of treatment, 36% of patients in the G-PUR® group vs 0% in the placebo group reported complete or considerable relief. An improvement in daily abdominal pain was noted in 94% vs 83% (P = 0.0353), and the median number of days with diarrhea per week decreased by 2.4 d vs 0.3 d in the G-PUR® and placebo groups, respectively. Positive trends were observed for 50% of responders in the Bristol Stool Form Scale. Positive trends were also noted for combined abdominal pain and stool consistency response and the Perceived Stress Questionnaire score. Only 64% in the G-PUR® group compared to 86% in the placebo group required rescue medication intake during the study. Stool microbiome studies showed a minor increase in diversity in the G-PUR® group but not in the placebo group. No PCT-related serious adverse events were reported. CONCLUSION: In this randomized, double-blind, placebo-controlled study, the PCT product, G-PUR®, demonstrated safety and clinical benefit towards some symptoms of IBS-D, representing a promising novel treatment option for these patients.

Topically administered purified clinoptilolite-tuff for the treatment of cutaneous wounds: A prospective, randomised phase I clinical trial.

In an ageing society, chronic ulcers pose an increasingly relevant healthcare issue associated with significant morbidity and an increasing financial burden. Hence, there is an unmet medical need for novel, cost-effective therapies that improve healing of chronic cutaneous wounds. This prospective, randomised, open-label, phase I trial investigated the safety and tolerability of topically administered purified clinoptilolite-tuff (PCT), mainly consisting of the naturally occurring zeolite-mineral clinoptilolite, in artificial wounds in healthy male volunteers compared to the standard of care (SoC). We found that topically administered PCT was safe for therapeutic application in acute wounds in healthy male volunteers. No significant differences in wound healing or wound conditions were observed compared to SoC-treated wounds. However, we found a significantly higher proportion of CD68-positive cells and a significantly lower proportion of α-smooth muscle actin-positive cells in PCT-treated wounds. Scanning electron microscopy revealed PCT particles in the restored dermis in some cases. However, these did not impede wound healing or clinical symptoms. Hence, purified PCT could represent an attractive, cost-effective wound treatment promoting the process of healing.

Concomitant oral intake of purified clinoptilolite tuff (G-PUR) reduces enteral lead uptake in healthy humans.

Lead exposure can cause substantial organ damage. Enteral lead absorption may be reduced by concomitant intake of clinoptilolite tuff, a zeolite from natural sources. This study aimed to assess the effect of purified clinoptilolite tuff (G-PUR) on enteral lead uptake in adults using stable lead isotope 204Pb as a tracer. In this randomized, placebo-controlled, double-blind, parallel-group study, 42 healthy participants were randomized to receive oral G-PUR 2.0 g, 2 * 2.0 g, or placebo, together with 2.5 µg of 204Pb in water. The enrichment of 204Pb caused by the tracer in blood and urine was measured by mass spectrometry. G-PUR was well tolerated. The mean maximum 204Pb enrichment of 0.505% of total blood lead was significantly higher (p < 0.0001) in the placebo group compared to G-PUR 2.0 g (0.073%) or G-PUR 2 * 2.0 g (0.057%) group. Normalized 204Pb AUC0-192 was 86.5, 11.9, and 8.5% * h without and with G-PUR 2.0 g, and G-PUR 2 * 2.0 g, respectively (p < 0.0001 vs. placebo). This smaller 204Pb exposure was paralleled by a reduced urinary excretion in subjects receiving G-PUR. Concomitant oral intake of purified clinoptilolite tuff reduced enteral uptake of 204Pb in healthy humans by approximately 90%. The reduced bioavailability is demonstrable by a decrease of 204Pb tracer enrichment in blood and urine.Trial registration: clinicaltrials.gov identifier: NCT04138693, registered 24/10/2019.

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.

Safety and tolerability of topically administered autologous, apoptotic PBMC secretome (APOSEC) in dermal wounds: a randomized Phase 1 trial (MARSYAS I).

Developing effective therapies against chronic wound healing deficiencies is a global priority. Thus we evaluated the safety of two different doses of topically administered autologous APOSEC, the secretome of apoptotic peripheral blood mononuclear cells (PBMCs), in healthy male volunteers with artificial dermal wounds. Ten healthy men were enrolled in a single-center, randomized, double-blinded, placebo-controlled phase 1 trial. Two artificial wounds at the upper arm were generated using a 4-mm punch biopsy. Each participant was treated with both topically applied APOSEC and placebo in NuGel for 7 consecutive days. The volunteers were randomized into two groups: a low-dose group (A) receiving the supernatant of 12.5 × 106 PBMCs and a high-dose group (B) receiving an equivalent of 25 × 106 PBMCs resuspended in NuGel Hydrogel. Irradiated medium served as placebo. The primary outcome was the tolerability of the topical application of APOSEC. All adverse events were recorded until 17 days after the biopsy. Local tolerability assessment was measured on a 4-point scale. Secondary outcomes were wound closure and epithelization at day 7. No therapy-related serious adverse events occurred in any of the participants, and both low- and high-dose treatments were well tolerated. Wound closure was not affected by APOSEC therapy.

A population-based analysis of the risk of drug interaction between clarithromycin and statins for hospitalisation or death.

BACKGROUND: Clarithromycin, known as a potent inhibitor of the cytochrome P450 isoenzyme CYP3A, may increase the plasma concentration of statins metabolized by this pathway; therefore, increase the risk of interaction with statins in reference to pharmacokinetic studies. This study aimed to characterize whether the concomitant use of a statin with clarithromycin is associated with serious outcomes among adult persons. METHODS: Health claims data of adult persons in the Regional Sickness Fund of Burgenland, Austria, who filled a prescription for clarithromycin between July 1, 2009 and June 30, 2012 were reviewed retrospectively. We assumed that the risk of hospitalisation increases acutely with the indication for taking an antibiotic, whereas statin use can be considered a chronic exposure with a low constant effect on hospitalisation. When defining the population as persons taking clarithromycin and the use of statins as the exposure we could achieve a comparable effect in both groups from the acute condition on hospitalisation. Therefore, we defined exposed patients as those who had overlapping treatment with a statin and unexposed controls as those who had filled a prescription for clarithromycin without concomitant statin therapy. Outcome was defined as a composite of hospital admission or death within 30 days after starting clarithromycin. We used generalised linear regression to model an association between outcome and exposure to statins. RESULTS: Among 28,484 prescriptions of clarithromycin, 2317 persons were co-exposed to statins. Co-administration of CYP3A4 metabolized statins and clarithromycin was associated with a 2.11 fold increased risk of death or hospitalisation (95 % confidence interval [CI]: 1.79-2.48). This effect was explained by age, evidence of cardiovascular disease, diabetes mellitus and utilization of other antibiotics (multivariable adjusted risk ratio: 1.02, 95 % CI: 0.85-1.22). The sensitivity analyses did not change the significance of effect. CONCLUSIONS: The risk for hospitalisation or death in persons receiving clarithromycin increases with age and cardiovascular disease but is not causally associated with statin-clarithromycine co-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.

Antioxidative capacity of a dietary supplement on retinal hemodynamic function in a human lipopolysaccharide (LPS) model.

PURPOSE: Beneficial effects of dietary supplements in age-related macular degeneration (AMD) are related to antioxidative properties. In the Age-Related Eye Disease Study 1 (AREDS 1), a reduced progression to late stage AMD was found using vitamin C, E, zinc, and ß-carotene. We showed previously that the AREDS 1 formulation restores the O2-induced retinal vasoconstrictor response of retinal vessels in a human endotoxin (lipopolysaccharide [LPS]) model. METHODS: We hypothesized that the abnormal O2-induced retinal red blood cell (RBC) flow response can be modulated by a different formulation (vitamin C, E, and zinc, lutein/zeaxanthin, selenium, taurine, Aronia extract, and omega-3 free fatty acids). A total of 43 healthy subjects was included in this randomized, double masked, placebo-controlled parallel group study. The reactivity of retinal arterial and venous diameter, RBC velocity, and flow to 100% O2 breathing was investigated in the absence and presence of 2 ng/kg LPS. Between the two study days was a 14-day period of daily dietary supplement intake. RESULTS: The decrease in retinal arterial diameter, RBC velocity, and flow during 100% O2 breathing was diminished significantly after LPS infusion. Dietary supplement intake for 14 days almost restored the response of retinal hemodynamic parameters to 100% O2 after LPS administration. This effect was significant for retinal arterial diameter (P = 0.03 between groups), and RBC velocity and flow (each P < 0.01 between groups). CONCLUSIONS: The present data indicate restoring of the RBC flow response to 100% O2 after LPS administration. This is likely due to an amelioration of endothelial dysfunction resulting from oxidative stress, a factor involved in AMD pathophysiology. (ClinicalTrials.gov number, NCT00914576.).

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.

Retinal hemodynamic effects of antioxidant supplementation in an endotoxin-induced model of oxidative stress in humans.

PURPOSE: The Age-Related Eye Disease Study 1 (AREDS 1) has shown that nutritional supplementation with antioxidants and zinc modifies the natural course of AMD. It is presumed that the supplements exert their beneficial effects by ameliorating oxidative stress due to the scavenging of reactive oxygen species (ROS). We have shown in a human model that under oxidative stress induced by administration of lipopolysaccharide (LPS) the vasoconstrictor response of retinal vessels to oxygen breathing is diminished. This reduced vascular response to hyperoxia was previously shown to be normalized by the AREDS 1 supplements. In the present study, we tested the hypothesis that the response can also be restored by a different antioxidant formulation. METHODS: This randomized, double-masked, placebo-controlled parallel group study included 40 healthy volunteers. On each study day, retinal red blood cell (RBC) flow and the reactivity of retinal RBC flow to hyperoxia were investigated in the absence and presence of 2 ng/kg LPS. Between the two study days, subjects received either the supplement or placebo for 14 days. RESULTS: Before supplementation LPS reduced retinal arterial vasoconstriction (P < 0.001) and reactivity of retinal RBC flow (P = 0.03) in response to 100% oxygen breathing. Two weeks of supplementation did not affect baseline retinal RBC flow, but normalized the LPS-induced change in the response to hyperoxia. The arterial vasoconstrictor response during LPS and 100% oxygen breathing was 4.1 ± 1.0% after administration of placebo and 10.6 ± 0.9% after supplementation (P = 0.005). The response of RBC flow to 100% oxygen breathing during LPS was 52.2 ± 2.1% after administration of placebo and 59.5 ± 2.0% after supplementation (P = 0.033). CONCLUSIONS: Our data show that the supplement used in the present study can normalize the response of retinal RBC flow to hyperoxia under LPS administration. This indicates that supplementation can prevent endothelial dysfunction induced by oxidative stress, which is assumed to play a role in the pathophysiology of AMD. (ClinicalTrials.gov number, NCT00914576.).

Association of endostatin with mortality in patients with chronic heart failure.

BACKGROUND: Experimental data imply that in decompensated heart failure (HF), the anti-angiogenic factor endostatin is increased. This study aimed to investigate whether the angiogenesis inhibitor endostatin is related to the risk of all-cause mortality in a prospective cohort study of chronic HF patients. METHODS: In this prospective observational cohort study, endostatin serum concentrations were determined in patients with chronic HF. Mortality data were recorded during a median follow-up of 31 months. RESULTS: One fifty one patients were included. The overall mortality rate was 20%. Baseline endostatin concentrations > 245 ng/mL were associated with higher risk of all-cause mortality [HR 8·7 (95% CI 2·5-30·0); P = 0·001] in the multivariate analysis as compared to endostatin concentrations ≤ 245 ng/mL. When both endostatin and NT-proBNP were above the calculated cut-off of 245 ng/mL and 2386 pg/mL, respectively, the prognostic utility of both biomarkers increased [HR 40·8 (95% CI 4·7-354·6); P = 0·001] compared with values lower than the cut-offs. CONCLUSIONS: Serum endostatin concentrations are independently associated with all-cause mortality. Furthermore, combination of endostatin and NT-proBNP discriminates patients at high risk.

Antiplatelet treatment for prevention of cerebrovascular events in patients with vascular diseases: a systematic review and meta-analysis.

BACKGROUND AND PURPOSE: The efficacy and safety of different antiplatelet regimes for prevention of stroke in patients at high risk were investigated in a systematic review and meta-analysis. METHODS: We searched the Cochrane Central Register of Controlled Trials, MEDLINE, and Web of Science. Twenty-two studies comprising 173 371 patients were included. RESULTS: In the overall population, dual antiplatelet therapy (DAPT) with aspirin and clopidogrel in comparison to aspirin monotherapy reduced the relative risk of total stroke by 20% (risk ratio [RR], 0.80; 95% confidence interval [CI], 0.73-0.88; P<0.0001; I(2)=28%) and of ischemic stroke or transient ischemic attack by 23% (RR, 0.77; 95% CI, 0.69-0.85; P<0.0001; I(2)=18%) without increasing the risk of intracranial hemorrhage. In the secondary prevention cohort, DAPT with aspirin and clopidogrel also reduced the relative risk of total stroke by 24% as compared with aspirin alone (RR, 0.76; 95% CI, 0.68-0.86; P<0.0001; I(2)=0%). DAPT with prasugrel or ticagrelor and aspirin versus DAPT with clopidogrel and aspirin was not associated with a risk reduction of stroke. CONCLUSIONS: DAPT with clopidogrel and aspirin compared with aspirin effectively reduces the risk of total and ischemic stroke in the overall cohort consisting of patients with cardiovascular disease without increase in intracranial hemorrhage, as well as decreases the risk of a recurrent total stroke in patients with a previous stroke/transient ischemic attack. Our meta-analysis suggests that DAPT including low-dose aspirin (75-100 mg) and clopidogrel (75 mg) should be further investigated as a strategy to reduce recurrent strokes. CLINICAL TRIAL REGISTRATION URL: http://www.crd.york.ac.uk/prospero. Unique identifier: CRD42011001596.

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.

Open-label, randomized study of the effect of rivaroxaban with or without acetylsalicylic acid on thrombus formation in a perfusion chamber.

INTRODUCTION: Rivaroxaban, a direct factor Xa inhibitor, has demonstrated effectiveness for the management of both venous and arterial thrombosis. This study was designed to investigate the antithrombotic effect of rivaroxaban, with or without acetylsalicylic acid (ASA), in an ex vivo perfusion chamber at both low and high shear rates. MATERIALS AND METHODS: Healthy subjects (N=51) were enrolled in a randomized, crossover (rivaroxaban 5, 10 or 20mg with or without ASA), and parallel-group (compared with ASA plus clopidogrel) study. Thrombi formed on pig aorta strips were measured after a 5-minute perfusion at low and high shear rates with blood from the subjects by measuring D-dimer concentration (for fibrin deposition) and P-selectin content (for platelet deposition). RESULTS: ASA alone had no impact on thrombus D-dimer levels, whereas rivaroxaban alone at peak concentrations decreased D-dimer levels by 9%, 84% and 65% at low shear rate and 37%, 73% and 74% at high shear rate after doses of 5, 10 and 20mg, respectively. Steady-state ASA plus rivaroxaban 5mg caused a greater reduction in D-dimer levels (63%) than monotherapy at low shear rate. Co-administration of ASA with clopidogrel was associated with a 30% decrease in D-dimer levels at low shear rate and a 14% decrease at high shear rate. No conclusive effect on P-selectin content was observed across the treatment groups. CONCLUSIONS: Rivaroxaban dose-dependently inhibited ex vivo thrombus formation under low and high shear rates. Co-administration of ASA had an additional effect on the antithrombotic action of low-dose rivaroxaban.

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.

Personalized antiplatelet treatment after percutaneous coronary intervention: the MADONNA study.

BACKGROUND AND OBJECTIVES: Clopidogrel non-responsiveness is associated with adverse clinical outcome. We aimed to investigate whether individualized antiplatelet treatment in clopidogrel non-responders is an effective and safe strategy. METHODS: This was a prospective non-randomized non-blinded study comparing two cohorts (guided and non-guided treatment) with a follow-up of 1-month. Responsiveness to clopidogrel was assessed by multiple electrode aggregometry (MEA) in 798 patients with coronary artery disease undergoing percutaneous coronary intervention (PCI). In the guided group (n=403) clopidogrel non-responders received repeated loading doses of clopidogrel or prasugrel, in the non-guided group (n=395) clopidogrel non-responders did not undergo any change in treatment. RESULTS: Stent thrombosis occurred significantly less often in the guided group than in the non-guided group (0.2% vs. 1.9%; p=0.027). The multivariate Cox regression analysis showed that patients in the non-guided group were at a 7.9-fold higher risk to develop stent thrombosis compared to the guided group (OR: 7.9; 95% CI: 1.08-69.2; p=0.048). In line with this, acute coronary syndrome occurred significantly less often in the guided group than in the non-guided group (0% vs. 2.5%; p=0.001) whereas there was no difference in the event rates of cardiac death (2% vs. 1.3%; p=0.422) or major bleedings (1% vs. 0.3%; p=0.186). CONCLUSION: Personalized antiplatelet treatment according to the platelet function testing with MEA resulted in an improved efficacy with an equal safety compared to the standard treatment.

Bioactivity of enoxaparin in critically ill patients with normal renal function.

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT: Venous thromboembolism is a frequent complication in critically ill patients that has a negative impact on patient outcomes. Critically ill patients have significantly lower plasma anti-factor-Xa activity levels compared with control patients after administration of subcutaneous heparin. The clinical relevance of the different anti-factor-Xa levels after prophylactic doses of low molecular weight heparin (LMWH) in critically ill patients is not completely understood. WHAT THIS STUDY ADDS: The standard dose of 40 mg enoxaparin led to a significant increase in anti-FXa levels in this selected cohort of ICU patients with normal renal function. This study found only subtle pharmacokinetic differences, but a comparable pharmacodynamic action, after enoxaparin administration in critically ill and normal medical ward patients. Thrombin generation with TGA RC-low and TGARC-high reagents was significantly reduced in ICU and normal ward patients after receiving LMWH. Both readouts appear equally useful for estimating the pharmacodynamics of enoxaparin. The ex vivo model of thrombosis was used for the first time in patients to evaluate the anti-thrombotic activity of LMWH. This method did not show any difference in thrombus formation after administration of enoxaparin in the individual group of patients. AIM: In critically ill patients, reduced anti-FXa plasma activity following subcutaneous administration of enoxaparin or nadroparin has been described. In this study, we aimed to investigate the bioactivity of enoxaparin in critically ill patients and controls. METHODS: A prospective, controlled, open label study was performed on a medical intensive care unit (ICU) and a general medical ward. Fifteen ICU patients (male = 12, median age 52 years [IQR 40-65], with a median Simplified Acute Physiology Score of 30 [IQR 18-52]) and sex- and age-matched medical ward patients were included. The anti-FXa plasma activity was measured after a single subcutaneous dose of40 mg enoxaparin. The thrombus size of a clot formed in an ex vivo perfusion chamber and endogenous thrombin potential (ETP) were measured. RESULTS: The anti-FXa plasma activity increased significantly after enoxaparin administration, with peak levels at 3 h after treatment, but was comparable between the ICU and medical ward groups (median 0.16 IU ml-1 [IQR 0-0.22 IU ml-1] vs. 0.2 IU ml-1 [IQR 0.15-0.27 IU ml-1],respectively, P = 0.13). The area under the anti-FXa activity curve from 0­12 h was similar between the groups (median 0.97 IU ml-1 h [IQR0.59-2.1] and 1.48 IU ml-1 h1 [IQR 0.83-1.62], P = 0.42 for the ICU group compared with the control group, respectively). The ETP was lower in the ICU group (P < 0.05) at baseline, but it was comparable at 3 h between the groups. Thrombus size decreased at 3 h compared with pre-dose (P = 0.029) and was not different between the groups. CONCLUSION: Similar bioactivity was achieved with a standard dose of subcutaneous enoxaparin in this selected cohort of ICU and general ward patients with normal renal function.

Human pharmacokinetics of intravenous recombinant human Cu/Zn superoxide dismutase.

OBJECTIVE: Oxidative stress plays an important role in human disease, but antioxidant therapies are limited. Under physiological conditions superoxide is controlled by the enzyme superoxide dismutase. A recombinant human Cu/Zn superoxide dismutase (rhSOD) might open new therapeutic possibilities. METHODS: Safety profile and pharmacokinetics in plasma and urine were assessed in an open label phase I study with dose-escalation. 18 healthy male volunteers received a single intravenous 10-minute infusion of 150, 300, or 600 mg rhSOD, respectively (n = 6 per dose group). RESULTS: rhSOD was well tolerated. Peak plasma concentrations (cmax; mean ± SD) were reached at the end of infusion, with 32.96 ± 10.31, 51.60 ± 8.23, and 103.90 ± 19.02 µg/ ml, respectively. Non-compartmental halflife was 1.06 ± 0.37, 1.59 ± 0.64, and 1.63 ± 0.28 hours. Urinary excretion (10 h) showed dose-dependent relative increases with 11.28 ± 6.46 (7.5%), 54.93 ± 15.25 (18.3%), and 191.81 ± 104.60 mg (32.0%). CONCLUSIONS: Our results show a good safety profile and predictable pharmacokinetics of rhSOD, suggesting that therapeutic exploratory studies might be safely conducted in humans.