Clinical effects of antiplatelet drugs and statins on D‐dimer levels

Background

Acute pulmonary embolism may be ruled out by combining nonhigh clinical probability and a normal D‐dimer level. Both antiplatelet drugs and HMG‐CoA reductase inhibitors (statins) have been associated with effects on thrombus formation, potentially influencing D‐dimer levels in this setting, leading to a higher rate of false‐negative tests. Therefore, we determined whether D‐dimer levels in patients with suspected pulmonary embolism are affected by concomitant use of antiplatelet drugs and/or statins and evaluated whether the effect of antiplatelet drugs or statins might affect diagnostic accuracy.

Materials and methods

We performed a posthoc analysis in the YEARS diagnostic study, comparing age‐ and sex‐adjusted D‐dimer levels among users of antiplatelet drugs, statins and nonusers. We then reclassified patients within the YEARS algorithm by developing a model in which we adjusted D‐dimer cut‐offs for statin use and evaluated diagnostic accuracy.

Results

We included 156 statins users, 147 antiplatelet drugs users and 726 nonusers of either drugs, all with suspected pulmonary embolism . Use of antiplatelet drugs did not have a significant effect, whereas statin use was associated with 15% decrease in D‐dimer levels (95% CI, ?28% to ?0.6%). An algorithm with lower D‐dimer thresholds in statin users yielded lower specificity (0.42 compared to 0.33) with no difference in false‐negative tests.

Conclusions

We conclude that use of statins but not of antiplatelet agents is associated with a modest decrease in D‐dimer levels. Adjusting D‐dimer cut‐offs for statin use did, however, not result in a safer diagnostic strategy in our cohort.

     

Effects of perioperative statins on patient outcomes after noncardiac surgery: a meta-analysis

Background: Cardiovascular complications are strongly correlated with a higher risk of mortality during follow-up after noncardiac surgery. However, controversy remains regarding whether perioperative administration of hydroxymethylglutaryl-CoA reductase inhibitors (statins) has a beneficial effect on patient outcomes.

Objective: We performed a meta-analysis to validate the hypothesis that perioperative statins improve patient outcomes after noncardiac surgery.

Methods: Electronic databases (PubMed, Web of Science, EMBASE, and the Cochrane Library) were searched for randomized controlled trials (RCTs) published up to 10 November 2017. RCTs were eligible for inclusion if they compared perioperative statin treatment with control treatment in patients scheduled for noncardiac surgery and reported data pertaining to clinical outcomes.

Results: Twelve RCTs involving 4707 patients (2371 in the perioperative statin group and 2336 in the control group) were ultimately included in this meta-analysis. The incidences of postoperative myocardial infarction, composite of death/myocardial infarction/stroke and new cases of atrial fibrillation were all lower in patients treated with statins than in control group patients, as shown by the fixed-effects model (odds ratio (OR)?=?0.460, 95% confidence interval (CI)?=?0.324–0.653, p?=?0 for myocardial infarction; OR?=?0.617, 95% CI?=?0.476–0.801, p?=?0 for composite of death/myocardial infarction/stroke; OR?=?0.406, 95% CI?=?0.247–0.666, p?=?0 for new atrial fibrillation). No significant differences in the incidences of stroke or transient ischemic attack, all-cause mortality and cardiovascular mortality were observed between the statin and control arms.

Conclusions: This meta-analysis supports the hypothesis that perioperative statins effectively reduce the incidences of postoperative myocardial infarction, composite of death/myocardial infarction/stroke and new cases of atrial fibrillation in patients undergoing noncardiac surgery.

• Key Messages

• Cardiovascular complications are strongly correlated with a higher risk of mortality during follow-up after noncardiac surgery.

• We performed a meta-analysis to confirm the hypothesis that perioperative statins improve patient outcomes after noncardiac surgery.

     

Bioactivation of loxoprofen to a pharmacologically active metabolite and its disposition kinetics in human skin

Loxoprofen (LX) is a prodrug‐type non‐steroidal anti‐inflammatory drug which is used not only as an oral drug but also as a transdermal formulation. As a pharmacologically active metabolite, the trans‐alcohol form of LX (trans‐OH form) is generated after oral administration to humans. The objectives of this study were to evaluate the generation of the trans‐OH form in human in vitro skin and to identify the predominant enzyme for its generation. In the permeation and metabolism study using human in vitro skin, both the permeation of LX and the formation of the trans‐OH form increased in a time‐ and dose‐dependent manner after the application of LX gel to the skin. In addition, the characteristics of permeation and metabolism of both LX and the trans‐OH form were examined by a mathematical pharmacokinetic model. The K_m value was calculated to be 10.3 mm in the human in vitro skin. The predominant enzyme which generates the trans‐OH form in human whole skin was identified to be carbonyl reductase 1 (CBR1) by immunodepletion using the anti‐human CBR1 antibody. The results of the enzyme kinetic study using the recombinant human CBR1 protein demonstrated that the K_m and V_max values were 7.30 mm and 402 nmol/min/mg protein, respectively. In addition, it was found that no unknown metabolites were generated in the human in vitro skin. This is the first report in which LX is bioactivated to the trans‐OH form in human skin by CBR1. Copyright © 2015 John Wiley & Sons, Ltd.     

细菌硝酸盐还原中的关键酶影响细菌耐药性的研究进展

硝酸盐的还原是细菌氮代谢中最重要的生化反应之一.随着对细菌耐药机制的不断探索,氮代谢过程尤其是某些代谢酶对细菌耐药性的影响得以揭示.作为硝酸盐还原过程中的关键代谢酶,硝酸还原酶(nitrate reductase,NR)与亚硝酸还原酶(nitrite reductase,NiR)不仅催化着细菌体内硝酸盐的一系列还原反应,还从多方面影响了细菌的耐药性.本文综述了NR/NiR与细菌耐药性之间关系的最新研究进展,以期为新药物靶标的发现及提出新治疗措施提供依据.     

Inhibitory effects of Serenoa repens on the kinetic of pig prostatic microsomal 5α-reductase activity

The pathogenesis of benign prostatic hyperplasia is linked to the accumulation of dihydrotestosterone (DHT), the active form of testosterone (T), in prostatic tissue. We have defined characteristics of 5α-reductase enzyme which catalyzes the conversion of T into DHT in prostatic microsomes of growing pigs. Peaks for the 5α-reductase activity were found at pH 5.5 and 8.0, which indicates the presence of both type 1 and type 2 isozymes. Kinetic parameters of porcine 5α-reductase in the presence of Serenoa repens extracts revealed uncompetitive, noncompetitive, and mixed types of inhibitions. Our results show the inhibitory action of S. repens on prostate porcine microsomal 5α-reductase activity.     

Role of pharmacogenomics and pharmacodynamics in the treatment of acute lymphoblastic leukaemia

Pharmacodynamic studies have been used to establish the relationships between the administered dosage and the concentration of drugs and metabolites in the blood or tissues and that between these concentrations and pharmacological effects. Polymorphisms in the genes that encode drug-metabolizing enzymes, drug transporters and drug targets can affect a person's response to therapy and may affect the development of de novo or therapy-related leukaemias. The burgeoning field of pharmacogenomics elucidates inherited differences in drug metabolism and treatment response. Increasingly, pharmacodynamic and pharmacogenomic studies are being used to individualize therapy to enhance efficacy and reduce toxicity.     

醛糖还原酶拮抗剂治疗大鼠血管再狭窄

背景醛糖还原酶增强氧化应激,促进细胞分裂增殖,激活转录因子、核因子кB(NF-кB),但在血管再狭窄中起的作用报告不多。目的研究醛糖还原酶(AR)在大鼠再狭窄血管中的表达,探讨AR表达与内膜增生的关系,AR拮抗剂依帕司他对再狭窄血管中AR的表达及AR的抑制作用。方法健康雄性SD大鼠24只,随机分成对照组(A组)、手术未干预组(B组)及手术+依帕司他组(C组),每组8只。用通气-干燥法损伤B组及C组大鼠右侧颈总动脉,左侧颈总动脉作为对照。分别于7d及14d后处死大鼠,HE染色以观察内膜及中膜增生情况,并计算内膜、中膜面积及其比值,FISH原位杂交及免疫组化检测AR及NF-кB的表达。结果1)术后第7天损伤侧血管内膜增生明显,第14天后内膜增生进一步加重,对照血管无明显增生。2)依帕司他明显抑制血管内皮损伤后血管内膜增生、血管内膜面积、血管内膜与中膜面积比值明显低于未干预组(P<0.05或P<0.01)。3)AR及NF-кB在损伤侧血管中的表达明显强于对侧。依帕司他明显抑制AR及NF-кB的表达量(P<0.05或P<0.01)。结论依帕司他对血管内膜的增生及再狭窄的形成有抑制作用,伴有AR及NF-кB的表达受抑。     

Ternary complex formation of AFN‐1252 with Acinetobacter baumannii FabI and NADH: Crystallographic and biochemical studies

Acinetobacter baumannii is an opportunistic Gram‐negative bacterial pathogen, associated mostly with hospital‐acquired infections. The emergence of drug resistance strains made it necessary to explore new pathways for the development of more effective antibiotics. Enoyl CoA reductase (FabI), a key enzyme in the fatty acid biosynthesis (FAS) pathway, has emerged as a potential target for antibacterial drug development. Earlier reports show that the lead SaFabI inhibitor AFN‐1252 can inhibit FabI from other organisms including Escherichia coli and Burkholderia pseudomallei, but with differential potency. In the present work, we show that AFN‐1252 is a moderate inhibitor of AbFabI with an IC₅₀ of 216 nM. AFN‐1252 stabilized AbFabI with a 4.2°C increase in the melting temperature (T_m) and, interestingly, the stabilization effect was significantly increased in presence of the cofactor NADH (?T_m = 17°C), suggesting the formation of a ternary complex AbFabI: AFN‐1252: NADH. X‐ray crystallography studies of AbFabI co‐crystalized with AFN‐1252 and NADH confirmed the ternary complex formation. The critical interactions of AFN‐1252 with AbFabI and NADH identified from the co‐crystal structure may facilitate the design and development of new drugs against A. baumannii infections by targeting the FAS pathway.     

MTHFR基因多态性与急性白血病易感性的研究

目的 研究汉族儿童亚甲基四氢叶酸还原酶(methylenetetrahydrofolate reductase,MTHFR)基因多态性与急性淋巴细胞白血病(acute lymphoblastic leukemia,ALL)以及急性髓细胞白血病(acute myeloid leukemia,AML)发病风险的相关性.方法 对87例ALL患儿、22例AML患儿和120名对照儿童用逆转录-聚合酶链反应-变性梯度凝胶电泳结合DNA测序技术进行MTHFR 677C/T和1298A/C基因的多态性筛查.结果 MTHFR 677CT基因型的个体AML易感性降低(OR=0.23,95％CI:0.07～0.79).未发现MTHFR 1298A/C各基因型与ALL和AML发病风险间存在显著关联.MTHFR 677TT/1298AA和677CC/1298AC基因型ALL发病风险增高(OR=3.78,95％ CI:1.38～10.40;OR=3.17,95％CI:1.18～8.53),677CT/1298AA基因型者AML风险降低(OR=0.23,95％ CI∶0.06～0.97).结论 MTHFR基因677位碱基变异可能是儿童AML遗传易感因素.