Slow-release aspirin and prostaglandin inhibition

[Preeclampsia: Guidelines for clinical practice from the French College of Obstetricians and Gynecologists]

OBJECTIVE

To identify strategies to reduce maternal and neonatal morbidity related to preeclampsia.

MATERIAL AND METHODS

The quality of evidence of the literature was assessed following the GRADE® method with questions formulated in the PICO format (Patients, Intervention, Comparison, Outcome) and outcomes defined a priori and classified according to their importance. An extensive bibliographic search was performed on PubMed, Cochrane, EMBASE and Google Scholar databases. The quality of the evidence was assessed (high, moderate, low, very low) and recommendations were formulated as a (i) strong, (ii) weak or (iii) no recommendation. The recommendations were reviewed in two rounds with external reviewers (Delphi survey) to select the consensus recommendations.

RESULTS

Preeclampsia is defined by the association of gestational hypertension (systolic blood pressure≥140mmHg and/or diastolic blood pressure≥90mmHg) and proteinuria≥0.3g/24h or a Proteinuria/Creatininuria ratio≥30mg/mmol occurring after 20 weeks of gestation. Data from the literature do not show any benefit in terms of maternal or perinatal health from implementing a broader definition of preeclampsia. Of the 31 questions, there was agreement between the working group and the external reviewers on 31 (100%). In general population, physical activity during pregnancy should be encouraged to reduce the risk of preeclampsia (Strong recommendation, Quality of the evidence low) but an early screening based on algorithms (Weak recommendation, Quality of the evidence low) or aspirin administration (Weak recommendation, Quality of the evidence very low) is not recommended to reduce maternal and neonatal morbidity related to preeclampsia. In women with preexisting diabetes or hypertension or renal disease, or multiple pregnancy, the level of evidence is insufficient to determine whether aspirin administration during pregnancy is useful to reduce maternal and perinatal morbidity (No recommendation, Quality of the evidence low). In women with a history of vasculo-placental disease, low dose of aspirin (Strong recommendation, Quality of the evidence moderate) at a dosage of 100-160mg per day (Weak recommendation, Quality of the evidence low), ideally before 16 weeks of gestation and not after 20 weeks of gestation (Strong recommendation, Quality of the evidence low) until 36 weeks of gestation (Weak recommendation, Quality of the evidence very low) is recommended. In a high-risk population, additional administration of low molecular weight heparin is not recommended (Weak recommendation, Quality of the evidence moderate). In case of preeclampsia (Weak recommendation, Quality of the evidence low) or suspicion of preeclampsia (Weak recommendation, Quality of the evidence moderate, the assessment of PlGF concentration or sFLT-1/PlGF ratio is not routinely recommended) in the only goal to reduce maternal or perinatal morbidity. In women with non-severe preeclampsia antihypertensive agent should be administered orally when the systolic blood pressure is measured between 140 and 159mmHg or diastolic blood pressure is measured between 90 and 109mmHg (Weak recommendation, Quality of the evidence low). In women with non-severe preeclampsia, delivery between 34 and 36+6 weeks of gestation reduces severe maternal hypertension but increases the incidence of moderate prematurity. Taking into account the benefit/risk balance for the mother and the child, it is recommended not to systematically induce birth in women with non-severe preeclampsia between 34 and 36+6 weeks of gestation (Strong recommendation, Quality of evidence high). In women with non-severe preeclampsia diagnosed between 37+0 and 41 weeks of gestation, it is recommended to induce birth to reduce maternal morbidity (Strong recommendation, Low quality of evidence), and to perform a trial of labor in the absence of contraindication (Strong recommendation, Very low quality of evidence). In women with a history of preeclampsia, screening maternal thrombophilia is not recommended (Strong recommendation, Quality of the evidence moderate). Because women with a history of a preeclampsia have an increased lifelong risk of chronic hypertension and cardiovascular complications, they should be informed of the need for medical follow-up to monitor blood pressure and to manage other possible cardiovascular risk factors (Strong recommendation, Quality of the evidence moderate).

CONCLUSION

The purpose of these recommendations was to reassess the definition of preeclampsia, and to determine the strategies to reduce maternal and perinatal morbidity related to preeclampsia, during pregnancy but also after childbirth. They aim to help health professionals in their daily clinical practice to inform or care for patients who have had or have preeclampsia. Synthetic information documents are also offered for professionals and patients.

Recent Advances of Halloysite Nanotubes in Biomedical Applications

Halloysite nanotubes (HNTs) have emerged as a highly regarded choice in biomedical research due to their exceptional attributes, including superior loading capacity, customizable surface characteristics, and excellent biocompatibility. HNTs feature tubular structures comprising alumina and silica layers, endowing them with a large surface area and versatile surface chemistries that facilitate selective modifications. Moreover, their substantial pore volume and wide range of pore sizes enable efficient entrapment of diverse functional molecules. This comprehensive review highlights the broad biomedical application spectrum of HNTs, shedding light on their potential as innovative and effective therapeutic agents across various diseases. It emphasizes the necessity of optimizing drug delivery techniques, developing targeted delivery systems, rigorously evaluating biocompatibility and safety through preclinical and clinical investigations, exploring combination therapies, and advancing scientific understanding. With further advancements, HNTs hold the promise to revolutionize the pharmaceutical industry, opening new avenues for the development of transformative treatments.

A randomized controlled trial of low-dose aspirin for the prevention of preeclampsia in women at high risk in China

BACKGROUND

Low-dose aspirin has been the most widely studied preventive drug for preeclampsia. However, guidelines differ considerably from country to country regarding the prophylactic use of aspirin for preeclampsia. There is limited evidence from large trials to determine the effect of 100 mg of aspirin for preeclampsia screening in women with high-risk pregnancies, based on maternal risk factors, and to guide the use of low-dose aspirin in preeclampsia prevention in China.

OBJECTIVE

The Low-Dose Aspirin in the Prevention of Preeclampsia in China study was designed to evaluate the effect of 100 mg of aspirin in preventing preeclampsia among high-risk pregnant women screened with maternal risk factors in China, where preeclampsia is highly prevalent, and the status of low-dose aspirin supply is commonly suboptimal.

STUDY DESIGN

We conducted a multicenter randomized controlled trial at 13 tertiary hospitals from 11 provinces in China between 2016 and 2019. We assumed that the relative reduction in the incidence of preeclampsia was at least 20%, from 20% in the control group to 16% in the aspirin group. Therefore, the targeted recruitment number was 1000 participants. Women were randomly assigned to the aspirin or control group in a 1:1 allocation ratio. Statistical analyses were performed according to an intention-to-treat basis. The primary outcome was the incidence of preeclampsia, diagnosed along with a systolic blood pressure of ≥140 mm Hg or a diastolic blood pressure of ≥90 mm Hg after 20 weeks of gestation, with a previously normal blood pressure (systolic blood pressure of <140 mm Hg and diastolic blood pressure of <90 mm Hg), and complicated by proteinuria. The secondary outcomes included maternal and neonatal outcomes. Logistic regression analysis was used to determine the significance of difference of preeclampsia incidence between the groups for both the primary and secondary outcomes. Interaction analysis was also performed.

RESULTS

A total of 1000 eligible women were recruited between December 2016 and March 2019, of which the final 898 patients were analyzed (464 participants in the aspirin group, 434 participants in the control group) on an intention-to-treat basis. No significant difference was found in preeclampsia incidence between the aspirin group (16.8% [78/464]) and the control group (17.1% [74/434]; relative risk, 0.986; 95% confidence interval, 0.738-1.317; P=.924). Likewise, adverse maternal and neonatal outcomes did not differ significantly between the 2 groups. Meanwhile, the incidence of postpartum hemorrhage between the 2 groups was similar (6.5% [30/464] in the aspirin group and 5.3% [23/434] in the control group; relative risk, 1.220; 95% confidence interval, 0.720-2.066; P=.459). We did not find any significant differences in preeclampsia incidence between the 2 groups in the subgroup analysis of the different risk factors.

CONCLUSION

A dosage of 100 mg of aspirin per day, initiated from 12 to 20 gestational weeks until 34 weeks of gestation, did not reduce the incidence of preeclampsia in pregnant women with high-risk factors in China.

The 15-Epilipoxin-A4 Pathway with Prophylactic Aspirin in Preventing Preeclampsia: A Longitudinal Cohort Study

INTRODUCTION

The benefit of aspirin in preventing preeclampsia is increasingly recognized; however, its mechanism of action remains unclear. Nonobstetric studies have described an anti-inflammatory effect of aspirin through the 15-epilipoxin-A4 pathway (aspirin-triggered lipoxin [ATL]). However, the anti-inflammatory mechanism of aspirin in the prevention of preeclampsia remains unknown.

OBJECTIVE/HYPOTHESIS

To examine (1) the difference in longitudinal endogenous lipoxin-A4 (En-Lipoxin-A4) concentration in low-risk (LR) and high-risk (HR) pregnancies, and (2) the effect of aspirin on endogenous ATL concentration and the associated effect on cytokine profile of HR women.

METHODS

Plasma from 220 HR women was collected at 12, 16, 20, 24, 28, 32, and 36 weeks of gestation. Adherence to aspirin was biochemically verified. Plasma En-Lipoxin-A4 and ATL concentrations were analyzed using liquid chromatography mass spectrometry, and cytokines, interleukin (IL)-10, tumor necrosis factor-α, interferon-γ, IL-8, and IL-1β, with the high-sensitivity multibead Luminex® assay.

RESULTS

HR women have up to 70% lower plasma concentration of En-Lipoxin-A4 (P < 0.001) than LR women. HR women with adequate aspirin adherence (HR-AA) (n = 82) had higher plasma concentration of ATL (P < .001), lower concentration of IL-8 from 16 to 36 weeks of gestation (P < .001), and increased IL-10 concentration from 16 to 28 weeks of gestation (P = .03) compared with high-risk women who were not on aspirin (HR-NA). HR-AA who did not develop preeclampsia had higher plasma En-lipoxin-A4 (P < .001), ATL (P = .02), and IL-10 concentrations (P < .001) with lower IL-8 concentration (P = .004) than HR women who developed preeclampsia.

DISCUSSION

Plasma concentration of En-Lipoxin-A4 is lower in HR women than in LR controls. Adequate adherence with aspirin results in an increase in ATL and IL-10 with reduced IL-8 plasma concentration. This study suggests a potential anti-inflammatory role of aspirin through the ATL pathway with prophylactic aspirin in HR pregnant women.

Effects of low-dose aspirin on the prevention of preeclampsia and pregnancy outcomes: A randomized controlled trial from Shanghai, China

OBJECTIVES

To evaluate the preventive effects of low-dose aspirin on the incidence of preeclampsia and pregnancy outcomes of women at high-risk for preeclampsia.

STUDY DESIGN

This prospective randomized clinical trial was conducted at the Obstetrics Department of The International Peace Maternity and Child Health Hospital, School of Medicine, Shanghai Jiao Tong University, China. It analyzed data from 1105 high-risk women who were divided into the control group (placebo group) and the aspirin group (including three subgroups: 25 mg, 50 mg and 75 mg). The aspirin group in this study was instructed to take aspirin daily before bedtime beginning in the 12th week of pregnancy.

MAIN OUTCOME MEASURES

The primary outcome is the occurrence of preeclampsia. The secondary outcomes included maternal and neonatal outcomes (such as premature delivery, FGR etc.), maternal serum biomarkers (including d-dimers, platelet aggregation rates, etc.) and uterine arterial blood flow resistance. The onset of preeclampsia and pregnancy outcomes were recorded after all participants delivered.

RESULTS

Low-dose aspirin significantly reduced the incidence of preeclampsia and early-onset preeclampsia. Aspirin also showed significant dose dependence in preeclampsia prevention. The results of Mantel-Haenszel trend test showed that there was a linear relationship between the dosage and the incidence of preeclampsia and early preeclampsia (P < 0.05). Pearson's results showed that the incidence of preeclampsia and early preeclampsia was negatively correlated with aspirin dosage. There was also a linear relationship between the dosage and the rates of postpartum hemorrhage, fetal growth restriction, premature births and cesarean section (P < 0.05). There was no evidence to suggest differences in the incidence of fetal distress, miscarriage and placental abruption among the four groups. The blood resistance S/D value of uterine artery in early pregnancy was the only independent factor affecting the efficacy of aspirin (OR = 1.405; 95 %CI,1.058-1.867; P = 0.019).

CONCLUSION

Low-dose aspirin can prevent preeclampsia and early-preeclampsia. Its efficacy is dose-dependent. It can reduce the rates of postpartum hemorrhage, fetal growth restriction, premature births and cesarean section. The prophylactic effect of aspirin on preeclampsia seemed to be greater in patients with higher blood resistance S/D value of uterine artery during early pregnancy.

Preeclampsia: Maternal Systemic Vascular Disorder Caused by Generalized Endothelial Dysfunction Due to Placental Antiangiogenic Factors

Preeclampsia, a systemic vascular disorder characterized by new-onset hypertension and proteinuria after 20 weeks of gestation, is the leading cause of maternal and perinatal morbidity and mortality. Maternal endothelial dysfunction caused by placental factors has long been accepted with respect to the pathophysiology of preeclampsia. Over the past decade, increased production of placental antiangiogenic factors has been identified as a placental factor leading to maternal endothelial dysfunction and systemic vascular dysfunction. This review summarizes the recent advances in understanding the molecular mechanisms of endothelial dysfunction caused by placental antiangiogenic factors, and the novel clinical strategies based on these discoveries.

[Aspirin and preeclampsia]

Indications for aspirin during pregnancy are a matter of debate and there is a recent trend to an extended prescription and an overuse of aspirin in pregnancy. Aspirin is efficient in secondary prevention of preeclampsia essentially in patients with a personal history of preeclampsia. The effect of aspirin on platelet aggregation and on the TXA2/PGI2 balance is dose-dependent. The optimum dosage, from 75mg/day to 150mg/day, needs to be determined. Fetal safety data at 150mg/day are still limited. The efficacy of aspirin seems to be subject to a chronobiological effect. It is recommended to prescribe an evening or bedtime intake. Aspirin, in primary prevention of preeclampsia, given to high-risk patients identified in the first trimester by screening tests, seems to reduce the occurrence of early-onset preeclampsia. Nevertheless, there are insufficient data for the implementation of such screening procedures in practice.

Aspirin for Prevention of Preeclampsia

Aspirin is currently the most widely prescribed treatment in the prevention of cardiovascular complications. The indications for the use of aspirin during pregnancy are, however, the subject of much controversy. Since the first evidence of the obstetric efficacy of aspirin in 1985, numerous studies have tried to determine the effect of low-dose aspirin on the incidence of preeclampsia, with very controversial results. Large meta-analyses including individual patient data have demonstrated that aspirin is effective in preventing preeclampsia in high-risk patients, mainly those with a history of preeclampsia. However, guidelines regarding the usage of aspirin to prevent preeclampsia differ considerably from one country to another. Screening modalities, target population, and aspirin dosage are still a matter of debate. In this review, we report the pharmacodynamics of aspirin, its main effects according to dosage and gestational age, and the evidence-based indications for primary and secondary prevention of preeclampsia.

Drug structure-transport relationships

Malcolm Rowland has greatly facilitated an understanding of drug structure–pharmacokinetic relationships using a physiological perspective. His view points, covering a wide range of activities, have impacted on my own work and on my appreciation and understanding of our science. This overview summarises some of our parallel activities, beginning with Malcolm’s work on the pH control of amphetamine excretion, his work on the disposition of aspirin and on the application of clearance concepts in describing the disposition of lidocaine. Malcolm also spent a considerable amount of time developing principles that define solute structure and transport/pharmacokinetic relationships using in situ organ studies, which he then extended to involve the whole body. Together, we developed a physiological approach to studying hepatic clearance, introducing the convection–dispersion model in which there was a spread in blood transit times through the liver accompanied by permeation into hepatocytes and removal by metabolism or excretion into the bile. With a range of colleagues, we then further developed the model and applied it to various organs in the body. One of Malcolm’s special interests was in being able to apply this knowledge, together with an understanding of physiological differences in scaling up pharmacokinetics from animals to man. The description of his many other activities, such as the development of clearance concepts, application of pharmacokinetics to the clinical situation and using pharmacokinetics to develop new compounds and delivery systems, has been left to others.

Focused antithrombotic therapy: novel anti-platelet salicylates with reduced ulcerogenic potential and higher first-pass detoxification than aspirin in rats

The use of aspirin as an anti-platelet drug is limited by its propensity to induce gastric injury and by its adverse effect on vascular prostacyclin formation. Two phenolic non-steroidal anti-inflammatory drugs (salicylic acid and diflunisal) were modified by esterification with a series of O-acyl moieties. The short-term ulcerogenic in vitro and in vivo anti-platelet properties, pharmacodynamic profiles, and extent of hepatic extraction of these phenolic esters were compared with aspirin (acetylsalicylic acid). The more lipophilic esters (longer carbon chain length in O-acyl group) show significantly less gastrotoxicity in stressed rats than does aspirin after a single oral dose. The in vitro and in vivo anti-platelet studies show that these phenolic esters inhibited (1) arachidonate-triggered human platelet aggregation and (2) thrombin-stimulated rat serum thromboxane A2 production by platelets in the clotting process almost as effectively as aspirin. The hepatic extractions of these O-acyl derivatives are significantly higher than those of aspirin. The pharmacodynamic studies show that these O-acyl derivatives of salicylic acid and diflunisal probably bind to, or combine with, the same site on the platelet cyclooxygenase as aspirin. Replacing the O-acetyl group with longer chain O-acyl moiety in this series of phenolic esters markedly reduced the potential of these agents to induce short-term gastric injury but did not lessen their activity as inhibitors of platelet aggregation. These non-acetyl salicylates may therefore represent a novel class of anti-platelet drugs with less ulcerogenic potential.

Hepatic structure-pharmacokinetic relationships: the hepatic disposition and metabolite kinetics of a homologous series of O-acyl derivatives of salicylic acid

1. The hepatic disposition and metabolite kinetics of a homologous series of O-acyl (acetyl, propionyl, butanoyl, pentanoyl, hexanoyl and octanoyl) esters of salicylic acid (C2SA, C3SA, C4SA, C5SA, C6SA and C8SA, respectively) was determined using a single-pass, in-situ rat liver preparation. 2. The hepatic venous outflow profiles for the parent esters and the generated metabolite, salicylic acid (SA) were analysed by HPLC. Non-parametric moments analysis was used to determine the area under the curve (AUC'), mean transit time (MTT) and normalized variance (CV2) for the parent esters and generated SA. 3. Pregenerated SA ([14C]-salicylic acid) was injected into each liver with the parent ester to determine its distribution characteristics. 4. The overall recovery of ester plus metabolite was 89% of the ester dose injected and independent of the ester carbon number, suggesting that ester extraction was due to hepatic metabolism to salicylic acid. 5. The metabolite AUC' value increased directly with the lipophilicity of the parent ester (from 0.12 for C2SA to 0.95 for C8SA). By contrast, the parent AUC' decreased with the lipophilicity (from 0.85 for C2SA to zero for C8SA). The metabolite MTT value also showed a trend to increase with the lipophilicity of the parent ester (from 15.72 s for C3SA to 61.97 s for C8SA). However, the parent MTT value shows no significant change across the series. 6. The two-compartment dispersion model was used to derive the kinetic parameters for parent ester, pregenerated SA and generated SA. Consequently, these parameters were used to estimate the values of AUC', MTT and CV2 for the parent ester and metabolite. The moments values obtained using the two-compartment dispersion model show similar trends to the corresponding moments values obtained from the outflow profiles using a non-parametric approach. 7. The more lipophilic aspirin analogues are more confined to the portal circulation after oral administration than aspirin due to their more extensive hepatic elimination avoiding systemic prostacyclin inhibition. Given that aspirin's selectivity as an anti-thrombotic agent has been postulated to be due to selective anti-platelet effects in the portal circulation, the more lipophilic and highly extracted analogues are potentially more selective anti-thrombotic agents than aspirin.

Hepatic disposition and metabolite kinetics of a homologous series of diflunisal esters

The hepatic disposition and metabolite kinetics of a homologous series of diflunisal O-acyl esters (acetyl, butanoyl, pentanoyl, and hexanoyl) were determined using a single-pass perfused in situ rat liver preparation. The experiments were conducted using 2% BSA Krebs-Henseleit buffer (pH 7.4), and perfusions were performed at 30 mL/min in each liver. O-Acyl esters of diflunisal and pregenerated diflunisal were injected separately into the portal vein. The venous outflow samples containing the esters and metabolite diflunisal were analyzed by high performance liquid chromatography (HPLC). The normalized outflow concentration-time profiles for each parent ester and the formed metabolite, diflunisal, were analyzed using statistical moments analysis and the two-compartment dispersion model. Data (presented as mean +/- standard error for triplicate experiments) was compared using ANOVA repeated measures, significance level P < 0.05. The hepatic availability (AUC'), the fraction of the injected dose recovered in the outflowing perfusate, for O-acetyldiflunisal (C2D = 0.21 +/- 0.03) was significantly lower than the other esters (0.34-0.38). However, RN/fu, the removal efficiency number RN divided by the unbound fraction in perfusate fu, which represents the removal efficiency of unbound ester by the liver, was significantly higher for the most lipophilic ester (O-hexanoyldiflunisal, C6D = 16.50 +/- 0.22) compared to the other members of the series (9.57 to 11.17). The most lipophilic ester, C6D, had the largest permeability surface area (PS) product (94.52 +/- 38.20 mL min-1 g-1 liver) and tissue distribution value VT (35. 62 +/- 11.33 mL g-1 liver) in this series. The MTT of these O-acyl esters of diflunisal were not significantly different from one another. However, the metabolite diflunisal MTTs tended to increase with the increase in the parent ester lipophilicity (11.41 +/- 2.19 s for C2D to 38.63 +/- 9.81 s for C6D). The two-compartment dispersion model equations adequately described the outflow profiles for the parent esters and the metabolite diflunisal formed from the O-acyl esters of diflunisal in the liver.

The use of low dose aspirin in pregnancy

Pregnancy-induced hypertension (PIH) in general and preeclampsia in particular are major causes of maternal and perinatal morbidity. Data from our studies and from a number of prospective controlled trials have suggested that aspirin in doses of 60-150 md/day during the second and third trimester reduces the risk of PIH and improves maternal and neonatal outcomes. The number of patients enrolled in these studies is relatively small. However, meta-analysis of existing trials suggests that low dose aspirin reduces the risk of PIH and severe low birth weight. Although no maternal or neonatal adverse effects associated with aspirin were observed, the use of aspirin in the third trimester has been reported to cause hemostatic abnormalities in both mother and neonate. Other complications associated with prostaglandin synthetase inhibitors include premature closure of the ductus and neonatal primary pulmonary hypertension. The use of aspirin in the first trimester is not associated with increased risk of structural malformations. On the basis of these findings and pending the results of ongoing large-scale randomized multicenter trials, we suggest that daily low dose aspirin (1 to 2 mg/kg/day) be recommended only for select women at high risk for developing PIH and its associated complications.

Inhibition of platelet function by low-dose plain and micro-encapsulated acetylsalicylic acid

The effect of two acetylsalicylic acid (ASA) formulations, plain (Magnyl) and micro-encapsulated (Globentyl), on platelet aggregation, thromboxane formation, and bleeding time was studied in 12 healthy volunteers in a randomized double-blind cross-over study. All subjects were treated with Magnyl and Globentyl (75 mg daily) in periods of 2 weeks, separated by a wash-out period of 2 weeks. Both drugs significantly depressed platelet aggregation and thromboxane formation and prolonged bleeding time without difference in mode of action of the drugs. It is concluded that significant inhibition of platelet activity may be achieved by low-dose ASA treatment with micro-encapsulated as well as with plain formulations.