Nitric Oxide and Aspirin: A New Mediator for an Old Drug

The Role of Xanthine Oxidase in Pregnancy Complications: A Systematic Review

Xanthine oxidoreductase (XOR) is an enzyme involved in the oxidation of hypoxanthine and xanthine to uric acid. XOR has two isoforms: xanthine dehydrogenase and xanthine oxidase (XO). XO plays a major role in oxidative stress, causing the formation of reactive oxygen species. In the present study, we aimed to summarize the evidence on the association between XO and pregnancy complications. The PRISMA checklist guided the reporting of the data. We conducted systematic searches in the PubMed and Web of Science databases to identify all human studies investigating XO in pregnancy diseases up to June 2024. A total of 195 references have been identified and 14 studies were included. Most studies focused on women with PE and GD. Overall, all the included studies found a statistically significant increase in maternal, placental, and/or fetal XO levels, activity, or tissue expression in women with pregnancy complications, compared to those with uncomplicated pregnancies. Although promising, the quality and dimension of the included studies do not allow for a definitive answer to the question of whether XO may play a crucial role in pregnancy complications. Future studies are warranted to confirm if XO could represent a prognostic and therapeutic marker in pregnancy complications and their impact on long-term maternal and offspring cardiovascular health.

Low-molecular-weight heparin in addition to low-dose aspirin for preventing preeclampsia and its complications: A systematic review and meta-analysis

BACKGROUND

In this systematic review, we aimed to investigate the efficacy and safety of adding low-molecular-weight heparin (LMWH) or unfractionated heparin to low-dose aspirin (LDA) started ≤16 weeks'gestation in the prevention of preeclampsia (PE) in high-risk women.

METHODS

PubMed, Cochrane Library, Embase, and ClinicalTrials.gov databases were searched from their inception to April 2022 for randomized controlled trials (RCTs) that to determine whether the combined treatment of LMWH and LDA is better than single anticoagulant drugs in preventing PE and improving live birth rate of fetus in high-risk women with pregnancy ≤16 weeks. We also searched Embase, OVID MEDLINE and OVID MEDLINE in-process using the OVID platform.

RESULTS

14 RCTs involving 1,966 women were found. The LMWH (or unfractionated heparin) and LDA groups included 1,165 wemen, and the LDA group included 960 women. The meta-analysis showed that the addition of LMWH to LDA reduced the risk of PE (RR: 0.59, 95% CI: 0.44-0.79, P < 0.05), small-for-gestational age (SGA, RR: 0.71, 95% CI: 0.52-0.97, P = 0.03), fetal and neonatal death (RR: 0.45, 95% CI: 0.23-0.88, P = 0.02) and gestational hypertension (RR: 0.47, 95% CI: 0.25-0.90, P = 0.02). It is worth emphasizing that LMWH (or unfractionated heparin) combined with LDA did not increase the risk of bleeding.

CONCLUSIONS

LMWH combined with LDA can effectively improve the pregnancy outcome of women with high risk factors for PE and its complications. Although this study showed that combined medication also did not increase the risk of bleeding, but such results lack the support of large sample size studies. The clinical safety analysis of LMWH combined with LDA in patients with PE should be more carried out.

Pleiotropic Effects of Acetylsalicylic Acid after Coronary Artery Bypass Grafting-Beyond Platelet Inhibition

Acetylsalicylic acid (ASA) is one of the most frequently used medications worldwide. Yet, the main indications for ASA are the atherosclerosis-based cardiovascular diseases, including coronary artery disease (CAD). Despite the increasing number of percutaneous procedures to treat CAD, coronary artery bypass grafting (CABG) remains the treatment of choice in patients with multivessel CAD and intermediate or high anatomical lesion complexity. Taking into account that CABG is a potent activator of inflammation, ASA is an important part in the postoperative therapy, not only due to ASA antiplatelet action, but also as an anti-inflammatory agent. Additional benefits of ASA after CABG include anticancerogenic, hypotensive, antiproliferative, anti-osteoporotic, and neuroprotective effects, which are especially important in patients after CABG, prone to hypertension, graft occlusion, atherosclerosis progression, and cognitive impairment. Here, we discuss the pleiotropic effects of ASA after CABG and provide insights into the mechanisms underlying the benefits of treatment with ASA, beyond platelet inhibition. Since some of ASA pleiotropic effects seem to increase the risk of bleeding, it could be considered a starting point to investigate whether the increase of the intensity of the treatment with ASA after CABG is beneficial for the CABG group of patients.

Immunometabolism and Pulmonary Infections: Implications for Protective Immune Responses and Host-Directed Therapies

The biology and clinical efficacy of immune cells from patients with infectious diseases or cancer are associated with metabolic programming. Host immune- and stromal-cell genetic and epigenetic signatures in response to the invading pathogen shape disease pathophysiology and disease outcomes. Directly linked to the immunometabolic axis is the role of the host microbiome, which is also discussed here in the context of productive immune responses to lung infections. We also present host-directed therapies (HDT) as a clinically viable strategy to refocus dysregulated immunometabolism in patients with infectious diseases, which requires validation in early phase clinical trials as adjuncts to conventional antimicrobial therapy. These efforts are expected to be continuously supported by newly generated basic and translational research data to gain a better understanding of disease pathology while devising new molecularly defined platforms and therapeutic options to improve the treatment of patients with pulmonary infections, particularly in relation to multidrug-resistant pathogens.

Aspirin: The Mechanism of Action Revisited in the Context of Pregnancy Complications

Aspirin is one of the most frequently used and cheapest drugs in medicine. It belongs to the non-steroidal anti-inflammatory drugs with a wide range of pharmacological activities, including analgesic, antipyretic, and antiplatelet properties. Currently, it is accepted to prescribe a low dose of aspirin to pregnant women who are at high risk of preeclampsia (PE) because it reduces the onset of this complication. Another pregnancy alteration in which a low dose of aspirin is recommended is the obstetric antiphospholipid syndrome (APS). The most recognized mechanism of action of aspirin is to inhibit the synthesis of prostaglandins but this by itself does not explain the repertoire of anti-inflammatory effects of aspirin. Later, another mechanism was described: the induction of the production of aspirin-triggered lipoxins (ATLs) from arachidonic acid by acetylation of the enzyme cyclooxygenase-2. The availability of a stable analog of ATL has stimulated investigations on the use of this analog and it has been found that, similar to endogenously produced lipoxins, ATL resolves inflammation and acts as antioxidant and immunomodulator. If we consider that in PE and in the obstetric APS, there is an underlying inflammatory process, aspirin might be used based on the induction of ATL. The objective of this review is to revisit the old and new mechanisms of action of aspirin. In particular, it intends to show other potential uses of this drug to prevent certain pregnancy complications in the light of its ability to induce anti-inflammatory and pro-resolving lipid-derived mediators.

Effect of ThermaCare HeatWraps and Icy Hot Cream/Patches on Skin and Quadriceps Muscle Temperature and Blood Flow

OBJECTIVES

The purpose of this study was to compare the effects of over-the-counter treatments-ThermaCare HeatWraps (chemical reaction to produce heat above the skin), Icy Hot Patch, and Icy Hot Cream (topically applied menthol)-on skin and deep tissue temperature.

METHODS

This was a longitudinal crossover study. On each of 3 days, a ThermaCare HeatWrap, Icy Hot Cream, or Icy Hot Patch was applied randomly over the quadriceps muscle in 15 healthy volunteers with normal body mass. Skin and muscle temperature and blood flow were measured by laser flowmetry every 15 minutes for 2 hours.

RESULTS

After 2 hours, mean temperature decreased by 2.1°C (7.0%; P = .02) in skin and 1.0°C (2.9%; P = .01) in muscle with Icy Hot Cream. Icy Hot Patch decreased skin and muscle temperature by 1.7°C (5.4%; P = .03) and 1.3°C (3.8%; P = .01), respectively. In contrast, ThermaCare raised skin and muscle temperature by 7.8°C (25.8%; P = .001) and 2.7°C (7.7%; P = .002), respectively; both were significantly warmer with ThermaCare vs either Icy Hot product (all P < .007). Icy Hot products produced a net decrease in skin blood flow (Cream: 56.7 flux [39.3%; P = .003]; Patch: 19.1 flux [16.7%; P = .045]). Muscle blood flow decreased with the Patch (6.7 flux [7.0%; P = .02]). After a period of fluctuations, Icy Hot Cream produced a net increase vs baseline of 7.0 flux (16.9%; P = .02). ThermaCare more than doubled blood flow in skin (83.3 flux [109.7%; P = .0003]) and muscle (25.1 flux [148.5%; P = .004]).

CONCLUSIONS

In this group of 15 healthy volunteers, ThermaCare HeatWraps provided the greatest degree of tissue warming and increase in tissue blood flow.

Aspirin and multiple sclerosis

Aspirin is widely used to lessen the risks of cardiovascular events. Some studies suggest that patients with multiple sclerosis have an increased risk for some cardiovascular events, for example, venous thromboembolism and perhaps ischemic strokes, raising the possibility that aspirin could lessen these increased risks in this population or subgroups (patients with limited mobility and/or antiphospholipid antibodies). However, aspirin causes a small increased risk of hemorrhagic stroke, which is a concern as it could potentially worsen a compromised blood-brain barrier. Aspirin has the potential to ameliorate the disease process in multiple sclerosis (for example, by limiting some components of inflammation), but aspirin also has the potential to inhibit mitochondrial complex I activity, which is already reduced in multiple sclerosis. In an experimental setting of a cerebral ischemic lesion, aspirin promoted the proliferation and/or differentiation of oligodendrocyte precursors, raising the possibility that aspirin could facilitate remyelination efforts in multiple sclerosis. Other actions by aspirin may lead to small improvements of some symptoms (for example, lessening fatigue). Here we consider potential benefits and risks of aspirin usage by patients with multiple sclerosis.

Does drug therapy reverse endothelial progenitor cell dysfunction in diabetes?

Endothelial progenitor cells (EPCs) are vital for the maintenance and repair of the endothelium. Decreased EPC number and function have been associated with increased cardiovascular (CVD) risk. Patients with diabetes have decreased number of circulating EPCs and decreased EPC function. This may account for some of the increased CVD risk seen in patients with diabetes that is not explained by traditional risk factors such as glycemic control, dyslipidemia and hypertension. Recent studies seem to indicate that drugs commonly used in diabetes patients such as metformin, thiazolidinediones, GLP-1 agonists, DPP-4 inhibitors, insulin, statins and ACE inhibitors may increase EPC number and improve EPC function. The mechanisms by which these drugs modulate EPC function may involve reduction in inflammation, oxidative stress and insulin resistance as well as an increase in nitric oxide (NO) bioavailability. This review will discuss the evidence in the literature regarding the above mentioned topics.

Aspirin in the treatment and prevention of cardiovascular disease: past and current perspectives and future directions

In secondary prevention among a wide range of patients who have survived a prior occlusive vascular event, as well as during acute myocardial infarction and acute occlusive stroke, aspirin produces statistically significant and clinically important reductions in the risk of subsequent myocardial infarction, stroke, and vascular death. In primary prevention, aspirin reduces risk of a first myocardial infarction, but the data on stroke and vascular deaths remain inconclusive. In addition, the average absolute risk of subjects randomized in the primary prevention trials was so low that it is not possible to get reliable estimates of the benefit-to-risk ratio in primary prevention in subjects at moderate risk. Until the results of ongoing trials are available, nobody would disagree that a nonfatal myocardial infarction or stroke is more likely to be disabling than a nonfatal bleed. Thus, in primary prevention at present, the appropriate and judicious use of aspirin by clinicians based on individual clinical judgments that weigh their absolute benefits against the absolute risks of the drug, will avoid premature morbidity and possibly, mortality.

Aspirin increases nitric oxide formation in chronic stable coronary disease

INTRODUCTION

There are no published randomized data on secondary prevention in humans about whether aspirin affects nitric oxide (NO) formation. In patients with chronic stable coronary disease, we tested whether aspirin at clinically relevant doses increases NO formation.

MATERIALS AND METHODS

In a randomized, double-blind trial, 37 patients from 2 cardiology office practices were assigned to daily doses of 81, 162.5, 325, 650, or 1300 aspirin for 12 weeks. Primary prespecified outcome measures were changes in heme oxygenase (HO-1), a downstream target of NO formation, and asymmetrical dimethyl arginine (ADMA), a competitive inhibitor of NO synthase.

RESULTS

There were no significant differences for HO-1 or ADMA between any of the clinically relevant doses of aspirin tested, so all were combined. For HO-1, there was a significant increase (10.29 ± 2.44, P < .001) from baseline (15.37 ± 1.85) to week 12 (25.66 ± 1.57). The mean ratio (MR) of week 12 to baseline for HO-1 was significantly higher than 1.0 (1.67, confidence interval [CI] from 1.60 to 1.74, P < .001). For ADMA, there was a significant decrease (-0.24 ± 0.11, P < .001) from baseline (0.78 ± 0.08) to week 12 (0.54 ± 0.07). The MR of week 12 to baseline for ADMA was significantly lower than 1.0 (0.69, CI from 0.66 to 0.73, P < .001).

CONCLUSIONS

In patients with chronic stable coronary disease, all clinically relevant daily doses of aspirin tested, from 81 to 1300 mg, produce similar and statistically significant increases in HO-1 and decreases in ADMA. These are the first randomized data on secondary prevention patients. These data support the hypothesis that aspirin has additional beneficial effects mediated through NO formation. Further research, including direct randomized comparisons on atherosclerosis using noninvasive techniques as well as on occlusive vascular disease events, is necessary.

Cu/Zn superoxide dismutase (SOD1) induction is implicated in the antioxidative and antiviral activity of acetylsalicylic acid in HCV-expressing cells

We evaluated the participation of oxidative stress in the negative regulation of hepatitis C virus (HCV)-RNA induced by acetylsalicylic acid (ASA). We used the HCV subgenomic replicon cell system that stably expresses HCV-nonstructural proteins (Huh7 HCV replicon cells) and the parental cell line. Cells were exposed to 4 mM ASA at different times (12-72 h), and pyrrolidine dithiocarbamate (PDTC) was used as an antioxidant control. Reactive oxygen species (ROS) production, oxidized protein levels, cytosolic superoxide dismutase (Cu/Zn-SOD), and glutathione peroxidase (GPx) activity were measured to evaluate oxidative stress. In addition, viral RNA and prostaglandin (PGE(2)) levels were determined. We observed that ASA treatment decreased ROS production and oxidized protein levels in a time-dependent fashion in both parental and HCV replicon cells with a greater extent in the latter. Similar results were found with PDTC exposure. Average GPx activity was decreased, whereas a striking increase was observed in average cytosolic SOD activity at 48 and 72 h in both cells exposed to ASA, compared with untreated cells. HCV replicon cells showed higher levels of Cu/Zn-SOD expression (mRNA and protein) with ASA treatment (48 and 72 h), whereas NS5A protein levels showed decreased expression. In addition, we found that inhibition of SOD1 expression reversed the effect of ASA. Interestingly, PDTC downregulated HCV-RNA expression (55%) and PGE(2) (60%) levels, imitating ASA exposure. These results suggest that ASA treatment could reduce cellular oxidative stress markers and modify Cu/Zn-SOD expression, a phenomenon that may contribute to the mechanisms involved in HCV downregulation.

A randomized trial of aspirin at clinically relevant doses and nitric oxide formation in humans

BACKGROUND

we performed the first test in humans of whether aspirin at clinically relevant doses increases nitric oxide (NO) formation.

METHODS

seventy primary prevention patients with metabolic syndrome were randomly assigned to 81 mg, 162.5 mg, 325 mg, 650 mg, or 1300 mg aspirin daily for 12 weeks to test changes in heme oxygenase (HO-1), a downstream target of NO formation and asymmetrical dimethylarginine (ADMA), a competitive inhibitor of NO synthase.

FINDINGS

for HO-1, the mean was 29.37 nanograms per milliliter at baseline and 57.45 at 12 weeks giving a mean ratio (MR) of 1.96 (P < .001) and 95% confidence interval (CI) from 1.91 to 2.00. There was no effect modification by dose or gender (P = .341). For ADMA, the mean was 1.70 micromoles per liter at baseline and 0.81 at 12 weeks, giving an MR of 0.48 (P < .001) and CI from 0.46 to 0.49. There was no effect modification by dose but a possible difference by gender (P = .055).

INTERPRETATION

in high-risk primary prevention patients, aspirin significantly increases markers of NO formation. All doses produce similar increases in HO-1 and decreases in ADMA. The antiplatelet properties of aspirin to irreversibly inhibit platelet dependent cyclooxygenase are sufficient to explain benefits in patients with occlusive vascular diseases. Nonetheless, these data contribute to the formulation of the hypothesis that aspirin has additional beneficial effects mediated through NO formation. Further research, including direct randomized comparisons on atherosclerosis using noninvasive techniques as well as on occlusive vascular disease events, is necessary to test whether this hypothesis has clinical or public health relevance.

Resveratrol attenuates lipopolysaccharide-induced hepatitis in D-galactosamine sensitized rats: role of nitric oxide synthase 2 and heme oxygenase-1

The goal of study was directed to investigate the effects of resveratrol (RES) pretreatment on the enhancing action of D-galactosamine (D-GalN; 800 mg/kg) on lipopolysaccharide (LPS; 0.5 microg/kg) inducing liver failure in rats. Liver function was assessed by determination of plasma alanine aminotransferase (ALT), aspartate aminotransferase (AST), alpha-glutathione S-transferase (alpha GST) and bilirubin (BILI). Plasma NO(2)(-) was assessed by NO(2)(-)/NO(3)(-) colorimetric kit. The estimation of nonenzymatic and enzymatic antioxidants (glutathione and catalase) was performed in plasma and liver homogenate. Lipid peroxidation was evaluated by the thiobarbituric acid reacting substances (TBARS) and the conjugated dienes (CD). Morphological examinations using light and electron microscopy were performed. Observations related to pharmacological increases of inducible nitric oxide synthase (NOS-2)/nitric oxide (NO) and inducible heme oxygenase (HO-1) in fulminant hepatic failure and modulation by resveratrol were followed up by real-time reverse transcription PCR (RT-PCR) in liver tissue. In the present study we found that among the mechanisms responsible for the hepatoprotective effect of resveratrol in the LPS/D-GalN liver toxicity model are reduction in NO, downregulation of NOS-2, modification of oxidative stress parameters and modulation of HO-1 which led to overall improvement in hepatotoxic markers and morphology after the hepatic insult.