Time-Dependent Effects of Aspirin on Blood Pressure and Morning Platelet Reactivity

The Role of the Circadian Rhythm in Dyslipidaemia and Vascular Inflammation Leading to Atherosclerosis

Cardiovascular diseases (CVD) are among the leading causes of death worldwide. Many lines of evidence suggest that the disturbances in circadian rhythm are responsible for the development of CVDs; however, circadian misalignment is not yet a treatable trait in clinical practice. The circadian rhythm is controlled by the central clock located in the suprachiasmatic nucleus and clock genes (molecular clock) located in all cells. Dyslipidaemia and vascular inflammation are two hallmarks of atherosclerosis and numerous experimental studies conclude that they are under direct influence by both central and molecular clocks. This review will summarise the results of experimental studies on lipid metabolism, vascular inflammation and circadian rhythm, and translate them into the pathophysiology of atherosclerosis and cardiovascular disease. We discuss the effect of time-respected administration of medications in cardiovascular medicine. We review the evidence on the effect of bright light and melatonin on cardiovascular health, lipid metabolism and vascular inflammation. Finally, we suggest an agenda for future research and recommend on clinical practice.

Circadian Modulation of the Antioxidant Effect of Grape Consumption: A Randomized Controlled Trial

Grape consumption acts on the immune system to produce antioxidant and anti-inflammatory effects. Since immune activity demonstrates circadian rhythmicity, with peak activity occurring during waking hours, the timing of grape intake may influence the magnitude of its antioxidant effect. This study followed a 2 × 2 factorial randomized, controlled design wherein healthy men and women (n = 32) consumed either a grape or placebo drink with a high-fat meal in the morning or evening. Urine was collected for measurements of biomarkers of oxidative stress and grape metabolites at baseline and post-meal at hour 1 and hours 1-6. F-2 isoprostane levels showed main effects of time period (baseline < hour 1 < hours 1-6, p < 0.0001), time (a.m. > p.m., p = 0.008) and treatment (placebo > grape, p = 0.05). Total F2-isoprostane excretion expressed as % baseline was higher in the a.m. vs. p.m. (p = 0.004) and in the a.m. placebo vs. all other groups (p < 0.05). Tartaric acid and resveratrol excretion levels were higher in the grape vs. placebo group (p < 0.05) but were not correlated with F-2 isoprostane levels. The findings support a protective effect of grape consumption against morning sensitivity to oxidative stress.

Understanding the role of chronopharmacology for drug optimization: what do we know?

INTRODUCTION

Circadian rhythm influences the pharmacokinetics and pharmacodynamics of a number of drugs and affects their therapeutic efficacy and toxicity depending on the time of day they are administered. Chronopharmacology is a method for incorporating knowledge about circadian rhythm into pharmacotherapy. Chronotherapy, which is the clinical application of chronopharmacology, is particularly relevant when the risk and/or severity of symptoms of a disease change in a predictable manner over time. Chronotherapy has potential benefits in the treatment of many diseases.

AREAS COVERED

Although a considerable amount of knowledge about chronopharmacology and chronotherapy has been accumulated, its therapeutic application in clinical practice remains limited in terms of therapy optimization. Resolution of these issues will improve our ability to deliver adequate drug treatment.

EXPERT OPINION

We propose four approaches for promoting chronotherapy-based drug treatment in clinical practice: targeting drug development and regulatory authorities; education about chronotherapy; drug information for both health professionals and consumers; and a chronotherapy network.

Consensus Recommendations for Standardized Data Elements, Scales, and Time Segmentations in Studies of Human Circadian/Diurnal Biology and Stroke

Increasing evidence indicates that circadian and diurnal rhythms robustly influence stroke onset, mechanism, progression, recovery, and response to therapy in human patients. Pioneering initial investigations yielded important insights but were often single-center series, used basic imaging approaches, and used conflicting definitions of key data elements, including what constitutes daytime versus nighttime. Contemporary methodologic advances in human neurovascular investigation have the potential to substantially increase understanding, including the use of large multicenter and national data registries, detailed clinical trial data sets, analysis guided by individual patient chronotype, and multimodal computed tomographic and magnetic resonance imaging. To fully harness the power of these approaches to enhance pathophysiologic knowledge, an important foundational step is to develop standardized definitions and coding guides for data collection, permitting rapid aggregation of data acquired in different studies, and ensuring a common framework for analysis. To meet this need, the Leducq Consortium International pour la Recherche Circadienne sur l'AVC (CIRCA) convened a Consensus Statement Working Group of leading international researchers in cerebrovascular and circadian/diurnal biology. Using an iterative, mixed-methods process, the working group developed 79 data standards, including 48 common data elements (23 new and 25 modified/unmodified from existing common data elements), 14 intervals for time-anchored analyses of different granularity, and 7 formal, validated scales. This portfolio of standardized data structures is now available to assist researchers in the design, implementation, aggregation, and interpretation of clinical, imaging, and population research related to the influence of human circadian/diurnal biology upon ischemic and hemorrhagic stroke.

ASPRE trial: effects of aspirin on mean arterial blood pressure and uterine artery pulsatility index trajectories in pregnancy

OBJECTIVES

The mechanism by which aspirin prevents pre-eclampsia is poorly understood, and its effects on biomarkers throughout pregnancy are unknown. We aimed to investigate the effects of aspirin on mean arterial pressure (MAP) and mean uterine artery pulsatility index (UtA-PI) using repeated measures from women at increased risk of preterm pre-eclampsia.

METHODS

This was a longitudinal secondary analysis of the Combined Multimarker Screening and Randomized Patient Treatment with Aspirin for Evidence-Based Pre-eclampsia Prevention (ASPRE) trial using repeated measures of MAP and UtA-PI. In the trial, 1620 women at increased risk of preterm pre-eclampsia were identified using the Fetal Medicine Foundation algorithm at 11 + 0 to 13 + 6 weeks, of whom 798 were randomly assigned to receive 150 mg/day aspirin and 822 were assigned to receive placebo daily from 11-14 weeks to 36 weeks of gestation or delivery, whichever came first. MAP and UtA-PI were measured at baseline and follow-up visits at 19-24, 32-34 and 36 weeks of gestation. Generalized additive mixed models with treatment by gestational age interaction terms were used to investigate the effects of aspirin on MAP and UtA-PI trajectories over time.

RESULTS

Among 798 participants in the aspirin group and 822 in the placebo group, there were 5951 MAP and 5942 UtA-PI measurements. Trajectories of raw and multiples of the median (MoM) values of MAP did not differ significantly between the two groups (MAP MoM analysis: P-value for treatment by gestational age interaction, 0.340). In contrast, trajectories of raw and MoM values of UtA-PI showed a significantly steeper decline in the aspirin group than in the placebo group, with the difference mainly driven by a more pronounced reduction before 20 weeks of gestation (UtA-PI MoM analysis: P-value for treatment by gestational age interaction, 0.006).

CONCLUSIONS

In women at increased risk of preterm pre-eclampsia, 150 mg/day aspirin initiated in the first trimester does not affect MAP but is associated with a significant decrease in mean UtA-PI, particularly before 20 weeks of gestation. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Circadian Factors in Stroke: A Clinician's Perspective

Stroke remains one of the leading causes of mortality and long-term and permanent disability worldwide despite technological innovations and developments in pharmacotherapy. In the last few decades, the growing data have evidenced the role of the circadian system in brain vulnerability to damage, the development and evolution of stroke, and short-term and long-term recovery. On the other hand, the stroke itself can affect the circadian system via direct injury of specific brain structures involved in circadian regulation (i.e., hypothalamus, retinohypothalamic tracts, etc.) and impairment of endogenous regulatory mechanisms, metabolic derangement, and a neurogenic inflammatory response in acute stroke. Moreover, the disruption of circadian rhythms can occur or exacerbate as a result of exogenous factors related to hospitalization itself, the conditions in the intensive care unit and the ward (light, noise, etc.), medication (sedatives and hypnotics), and loss of external factors entraining the circadian rhythms. In the acute phase of stroke, patients demonstrate abnormal circadian variations in circadian biomarkers (melatonin, cortisol), core body temperature, and rest-activity patterns. The approaches aimed at the restoration of disrupted circadian patterns include pharmacological (melatonin supplementation) and non-medication (bright light therapy, shifting feeding schedules, etc.) interventions; however, their effects on short- and long-term recovery after stroke are not well understood.

Insight on Cardiac Chronobiology and Latest Developments of Chronotherapeutic Antihypertensive Interventions for Better Clinical Outcomes

Cardiac circadian rhythms are an important regulator of body functions, including cardiac activities and blood pressure. Disturbance of circadian rhythm is known to trigger and aggravate various cardiovascular diseases. Thus, modulating the circadian rhythm can be used as a therapeutic approach to cardiovascular diseases. Through this work, we intend to discuss the current understanding of cardiac circadian rhythms, in terms of quantifiable parameters like BP and HR. We also elaborate on the molecular regulators and the molecular cascades along with their specific genetic aspects involved in modulating circadian rhythms, with specific reference to cardiovascular health and cardiovascular diseases. Along with this, we also presented the latest pharmacogenomic and metabolomics markers involved in chronobiological control of the cardiovascular system along with their possible utility in cardiovascular disease diagnosis and therapeutics. Finally, we reviewed the current expert opinions on chronotherapeutic approaches for utilizing the conventional as well as the new pharmacological molecules for antihypertensive chronotherapy.

Circadian rhythms of risk factors and management in atherosclerotic and hypertensive vascular disease: Modern chronobiological perspectives of an ancient disease

Atherosclerosis, a chronic inflammatory disease of the arteries that appears to have been as prevalent in ancient as in modern civilizations, is predisposing to life-threatening and life-ending cardiac and vascular complications, such as myocardial and cerebral infarctions. The pathogenesis of atherosclerosis involves intima plaque buildup caused by vascular endothelial dysfunction, cholesterol deposition, smooth muscle proliferation, inflammatory cell infiltration and connective tissue accumulation. Hypertension is an independent and controllable risk factor for atherosclerotic cardiovascular disease (CVD). Conversely, atherosclerosis hardens the arterial wall and raises arterial blood pressure. Many CVD patients experience both atherosclerosis and hypertension and are prescribed medications to concurrently mitigate the two disease conditions. A substantial number of publications document that many pathophysiological changes caused by atherosclerosis and hypertension occur in a manner dependent upon circadian clocks or clock gene products. This article reviews progress in the research of circadian regulation of vascular cell function, inflammation, hemostasis and atherothrombosis. In particular, it delineates the relationship of circadian organization with signal transduction and activation of the renin-angiotensin-aldosterone system as well as disturbance of the sleep/wake circadian rhythm, as exemplified by shift work, metabolic syndromes and obstructive sleep apnea (OSA), as promoters and mechanisms of atherogenesis and risk for non-fatal and fatal CVD outcomes. This article additionally updates advances in the clinical management of key biological processes of atherosclerosis to optimally achieve suppression of atherogenesis through chronotherapeutic control of atherogenic/hypertensive pathological sequelae.

Understanding the dosing-time-dependent antihypertensive effect of valsartan and aspirin through mathematical modeling

Chronopharmacology of arterial hypertension impacts the long-term cardiovascular risk of hypertensive subjects. Therefore, clinical and computational studies have proposed optimizing antihypertensive medications' dosing time (Ta). However, the causes and mechanisms underlying the Ta-dependency antihypertensive effect have not been elucidated. Here we propose using a Ta- dependent effect model to understand and predict the antihypertensive effect of valsartan and aspirin throughout the day in subjects with grade I or II essential hypertension. The model based on physiological regulation mechanisms includes a periodic function for each parameter that changes significantly after treatment. Circadian variations of parameters depending on the dosing time allowed the determination of regulation mechanisms dependent on the circadian rhythm that were most relevant for the action of each drug. In the case of valsartan, it is the regulation of vasodilation and systemic vascular resistance. In the case of aspirin, the antithrombotic effect generates changes in the sensitivity of systemic vascular resistance and heart rate to changes in physical activity. Dosing time-dependent models predict a more significant effect on systemic vascular resistance and blood pressure when administering valsartan or aspirin at bedtime. However, circadian dependence on the regulation mechanisms showed different sensitivity of their circadian parameters and shapes of functions, presenting different phase shifts and amplitude. Therefore, different mechanisms of action and pharmacokinetic properties of each drug can generate different profiles of Ta-dependence of antihypertensive effect and optimal dosing times.

Intermittent hypoxia conditioning as a potential prevention and treatment strategy for ischemic stroke: Current evidence and future directions

Ischemic stroke (IS) is the leading cause of disability and death worldwide. Owing to the aging population and unhealthy lifestyles, the incidence of cerebrovascular disease is high. Vascular risk factors include hypertension, diabetes, dyslipidemia, and obesity. Therefore, in addition to timely and effective reperfusion therapy for IS, it is crucial to actively control these risk factors to reduce the incidence and recurrence rates of IS. Evidence from human and animal studies suggests that moderate intermittent hypoxia (IH) exposure is a promising therapeutic strategy to ameliorate common vascular risk factors and comorbidities. Given the complex pathophysiological mechanisms underlying IS, effective treatment must focus on reducing injury in the acute phase and promoting repair in the recovery phase. Therefore, this review discusses the preclinical perspectives on IH conditioning as a potential treatment for neurovascular injury and highlights IH pre and postconditioning strategies for IS. Hypoxia conditioning reduces brain injury by increasing resistance to acute ischemic and hypoxic stress, exerting neuroprotective effects, and promoting post-injury repair and regeneration. However, whether IH produces beneficial effects depends not only on the hypoxic regimen but also on inter-subject differences. Therefore, we discuss the factors that may influence the effectiveness of IH treatment, including age, sex, comorbidities, and circadian rhythm, which can be used to help identify the optimal intervention population and treatment protocols for more accurate, individualized clinical translation. In conclusion, IH conditioning as a non-invasive, non-pharmacological, systemic, and multi-targeted intervention can not only reduce brain damage after stroke but can also be applied to the prevention and functional recovery of IS, providing brain protection at different stages of the disease. It represents a promising therapeutic strategy. For patients with IS and high-risk groups, IH conditioning is expected to develop as an adjunctive clinical treatment option to reduce the incidence, recurrence, disability, and mortality of IS and to reduce disease burden.

Ageing and Low-Level Chronic Inflammation: The Role of the Biological Clock

Ageing is a multifactorial physiological manifestation that occurs inexorably and gradually in all forms of life. This process is linked to the decay of homeostasis due to the progressive decrease in the reparative and regenerative capacity of tissues and organs, with reduced physiological reserve in response to stress. Ageing is closely related to oxidative damage and involves immunosenescence and tissue impairment or metabolic imbalances that trigger inflammation and inflammasome formation. One of the main ageing-related alterations is the dysregulation of the immune response, which results in chronic low-level, systemic inflammation, termed "inflammaging". Genetic and epigenetic changes, as well as environmental factors, promote and/or modulate the mechanisms of ageing at the molecular, cellular, organ, and system levels. Most of these mechanisms are characterized by time-dependent patterns of variation driven by the biological clock. In this review, we describe the involvement of ageing-related processes with inflammation in relation to the functioning of the biological clock and the mechanisms operating this intricate interaction.

Rev-erbs agonist SR9009 alleviates ischemia-reperfusion injury by heightening endogenous cardioprotection at onset of type-2 diabetes in rats: Down-regulating ferritinophagy/ferroptosis signaling

The complex progression of type-2 diabetes (T2DM) results in inconsistent findings on myocardial susceptibility to ischemia-reperfusion (IR). IR injuries in multiple organs interconnect with ferroptosis. Targeting Rev-erbs might limit ferroptosis, with increasing attention turning to the application of circadian medicine against IR injuries. However, whether the Rev-erbs agonist SR9009 could mitigate diabetic IR injury remains unknown. Here, we investigated the susceptibility to IR at onset of T2DM in rats and its potential association between SR9009 and ferritinophagy/ferroptosis signaling. Onset of T2DM model was induced with a high-fat diet and the intraperitoneal injection of a low dose of streptozotocin. Myocardial IR model was established as well. Rats' general characteristics, cardiac function, glycolipid profiles, serum biochemistry, apoptosis index (AI) and morphological histology were observed and analyzed. Western blot and immunofluorescence (IF) were employed to evaluate the expression of ferritinophagy/ferroptosis signaling and its co-localization. Glycolipid profiles and cardiac diastolic function were significantly impaired in diabetic rats. CK-MB, AI levels and ferritinophagy/ferroptosis-related proteins expression decreased towards myocardial IR in diabetic rats compared to non-diabetic rats'. The ferroptosis inducer Erastin up-regulated SOD, MDA, and AI levels, as well as the expression of ferritinophagy/ferroptosis-related proteins in diabetic rats towards IR. Treatment with SR9009 down-regulated the degree of myocardial injury and ferritinophagy/ferroptosis-related proteins expression compared to diabetic rats treated with or without Erastin. Onset of T2DM activated endogenous cardioprotection against the susceptibility to myocardial IR injury, and SR9009 exogenously enhanced this endogenous mechanism and alleviated myocardial IR injury at onset of T2DM by down-regulating ferritinophagy/ferroptosis signaling.

The circadian system, sleep, and the health/disease balance: a conceptual review

The field of "circadian medicine" is a recent addition to chronobiology and sleep research efforts. It represents a logical step arising from the increasing insights into the circadian system and its interactions with life in urbanised societies; applying these insights to the health/disease balance at home and in the medical practice (outpatient) and clinic (inpatient). Despite its fast expansion and proliferating research efforts, circadian medicine lacks a formal framework to categorise the many observations describing interactions among the circadian system, sleep, and the health/disease balance. A good framework allows us to categorise observations and then assign them to one or more components with hypothesised interactions. Such assignments can lead to experiments that document causal (rather than correlational) relationships and move from describing observations to discovering mechanisms. This review details such a proposed formal framework for circadian medicine and will hopefully trigger discussion among our colleagues, so that the framework can be improved and expanded. As the basis of the framework for circadian medicine, we define "circadian health" and how it links to general health. We then define interactions among the circadian system, sleep, and the health/disease balance and put the framework into the context of the literature with examples from six domains of health/disease balance: fertility, cancer, immune system, mental health, cardiovascular, and metabolism.

Chronoeffects of the Herbal Medicines Puerariae radix and Coptidis rhizoma in Mice: A Potential Role of REV-ERBα

Identifying drugs with dosing time-dependent effects (chronoeffects) and understanding the underlying mechanisms would help to improve drug treatment outcome. Here, we aimed to determine chronoeffects of the herbal medicines Puerariae radix (PR) and Coptidis rhizoma (CR), and investigate a potential role of REV-ERBα as a drug target in generating chronoeffects. The pharmacological effect of PR on hyperhomocysteinemia in mice was evaluated by measuring total homocysteine, triglyceride levels and lipid accumulation. PR dosed at ZT10 generated a stronger effect on hyperhomocysteinemia than drug dosed at ZT2. Furthermore, PR increased the expression levels of REV-ERBα target genes Bhmt, Cbs and Cth (encoding three key enzymes responsible for homocysteine catabolism), thereby alleviating hyperhomocysteinemia in mice. Moreover, CR attenuated chronic colitis in mice in a dosing time-dependent manner based on measurements of disease activity index, colon length, malondialdehyde/myeloperoxidase activities and IL-1β/IL-6 levels. ZT10 dosing generated a stronger anti-colitis effect as compared to ZT2 dosing. This was accompanied by lower production of colonic inflammatory cytokines (i.e., Nlrp3, IL-1β, IL-6, Tnf-α and Ccl2, REV-ERBα target genes) in colitis mice dosed at ZT10. The diurnal patterns of PR and CR effects were respectively consistent with those of puerarin (a main active constituent of PR, a REV-ERBα antagonist) and berberine (a main active constituent of CR, a REV-ERBα agonist). In addition, loss of Rev-erbα in mice abolished the dosing time-dependency in PR and CR effects. In conclusion, the therapeutic effects of PR and CR depend on dosing time in mice, which are probably attributed to diurnal expression of REV-ERBα as the drug target. Our findings have implications for improving therapeutic outcomes of herbal medicines with a chronotherapeutic approach.

Implications of Circadian Rhythm in Stroke Occurrence: Certainties and Possibilities

Stroke occurrence is not randomly distributed over time but has circadian rhythmicity with the highest frequency of onset in the morning hours. This specific temporal pattern is valid for all subtypes of cerebral infarction and intracerebral hemorrhage. It also correlates with the circadian variation of some exogenous factors such as orthostatic changes, physical activity, sleep-awake cycle, as well as with endogenous factors including dipping patterns of blood pressure, or morning prothrombotic and hypofibrinolytic states with underlying cyclic changes in the autonomous system and humoral activity. Since the internal clock is responsible for these circadian biological changes, its disruption may increase the risk of stroke occurrence and influence neuronal susceptibility to injury and neurorehabilitation. This review aims to summarize the literature data on the circadian variation of cerebrovascular events according to physiological, cellular, and molecular circadian changes, to survey the available information on the chronotherapy and chronoprophylaxis of stroke and its risk factors, as well as to discuss the less reviewed impact of the circadian rhythm in stroke onset on patient outcome and functional status after stroke.

COVID-19: Sleep, Circadian Rhythms and Immunity - Repurposing Drugs and Chronotherapeutics for SARS-CoV-2

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has affected nearly 28 million people in the United States and has caused more than five hundred thousand deaths as of February 21, 2021. As the novel coronavirus continues to take its toll in the United States and all across the globe, particularly among the elderly (>65 years), clinicians and translational researchers are taking a closer look at the nexus of sleep, circadian rhythms and immunity that may contribute toward a more severe coronavirus disease-19 (COVID-19). SARS-CoV-2-induced multi-organ failure affects both central and peripheral organs, causing increased mortality in the elderly. However, whether differences in sleep, circadian rhythms, and immunity between older and younger individuals contribute to the age-related differences in systemic dysregulation of target organs observed in SARS-CoV-2 infection remain largely unknown. Current literature demonstrates the emerging role of sleep, circadian rhythms, and immunity in the development of chronic pulmonary diseases and respiratory infections in human and mouse models. The exact mechanism underlying acute respiratory distress syndrome (ARDS) and other cardiopulmonary complications in elderly patients in combination with associated comorbidities remain unclear. Nevertheless, understanding the critical role of sleep, circadian clock dysfunction in target organs, and immune status of patients with SARS-CoV-2 may provide novel insights into possible therapies. Chronotherapy is an emerging concept that is gaining attention in sleep medicine. Accumulating evidence suggests that nearly half of all physiological functions follow a strict daily rhythm. However, healthcare professionals rarely take implementing timed-administration of drugs into consideration. In this review, we summarize recent findings directly relating to the contributing roles of sleep, circadian rhythms and immune response in modulating infectious disease processes, and integrate chronotherapy in the discussion of the potential drugs that can be repurposed to improve the treatment and management of COVID-19.

Contemporary Clinical Use of Aspirin: Mechanisms of Action, Current Concepts, Unresolved Questions, and Future Perspectives

The ability of aspirin to inhibit platelet aggregation has positioned this agent within the most frequently used drugs worldwide. The aim of this article is to review the contemporary clinical use of aspirin and also to discuss unresolved issues not yet translated into clinical practice. Results from several clinical trials have led to strong guideline recommendations for aspirin use in the acute management and secondary prevention of cardiovascular disease. On the contrary, guidelines regarding aspirin use as primary prevention of cardiovascular disease are almost conservative, supported by recent trials reporting that the bleeding risk outweighs the potential benefits in most patients. In pregnancy, aspirin has proved efficient in preventing preeclampsia and small-for-gestational-age births in women at high risk, and is hence widely recommended in clinical guidelines. Despite the vast amount of clinical data on aspirin, several unresolved questions remain. Randomized trials have reported that aspirin reduces the risk of recurrent venous thromboembolism, but the clinical relevance remains limited, because direct oral anticoagulants are more effective. Laboratory studies suggest that a twice-daily dosing regimen or evening intake may lead to more efficient platelet inhibition, and the potential clinical benefit of such strategies is currently being explored in ongoing clinical trials. Enteric-coated formulations of aspirin are frequently used, but it remains unclear if they are safer and as efficient as plain aspirin. In the future, aspirin use after percutaneous coronary interventions might not be mandatory in patients who also need anticoagulant therapy, as several trials support shorter aspirin duration strategies. On the other hand, new treatment indications for aspirin will likely arise, as there is growing evidence that aspirin may reduce the risk of colorectal cancer and other types of cancer.

Clocks, Rhythms, Sex, and Hearts: How Disrupted Circadian Rhythms, Time-of-Day, and Sex Influence Cardiovascular Health

Cardiovascular diseases are the top cause of mortality in the United States, and ischemic heart disease accounts for 16% of all deaths around the world. Modifiable risk factors such as diet and exercise have often been primary targets in addressing these conditions. However, mounting evidence suggests that environmental factors that disrupt physiological rhythms might contribute to the development of these diseases, as well as contribute to increasing other risk factors that are typically associated with cardiovascular disease. Exposure to light at night, transmeridian travel, and social jetlag disrupt endogenous circadian rhythms, which, in turn, alter carefully orchestrated bodily functioning, and elevate the risk of disease and injury. Research into how disrupted circadian rhythms affect physiology and behavior has begun to reveal the intricacies of how seemingly innocuous environmental and social factors have dramatic consequences on mammalian physiology and behavior. Despite the new focus on the importance of circadian rhythms, and how disrupted circadian rhythms contribute to cardiovascular diseases, many questions in this field remain unanswered. Further, neither time-of-day nor sex as a biological variable have been consistently and thoroughly taken into account in previous studies of circadian rhythm disruption and cardiovascular disease. In this review, we will first discuss biological rhythms and the master temporal regulator that controls these rhythms, focusing on the cardiovascular system, its rhythms, and the pathology associated with its disruption, while emphasizing the importance of the time-of-day as a variable that directly affects outcomes in controlled studies, and how temporal data will inform clinical practice and influence personalized medicine. Finally, we will discuss evidence supporting the existence of sex differences in cardiovascular function and outcomes following an injury, and highlight the need for consistent inclusion of both sexes in studies that aim to understand cardiovascular function and improve cardiovascular health.

Vascular Inflammation in Hypertension: Targeting Lipid Mediators Unbalance and Nitrosative Stress

Arterial hypertension is a worldwide public health threat. High Blood Pressure (BP) is commonly associated with endothelial dysfunction, nitric oxide synthases (NOS) unbalance and high peripheral vascular resistance. In addition to those, inflammation has also been designated as one of the major components of BP increase and organ damage in hypertension. This minireview discusses vascular inflammatory triggers of high BP and aims to fill the existing gaps of antiinflammatory therapy of hypertension. Among the reasons discussed, enhanced prostaglandins rather than resolvins lipid mediators, immune cell infiltration and oxidative/nitrosative stress are pivotal players of BP increase within the inflammatory hypothesis. To address these inflammatory targets, this review also proposes new concepts in hypertension treatment with non-steroidal antiinflammatory drugs (NSAIDs), nitric oxide-releasing NSAIDs (NO-NSAIDs) and specialized proresolving mediators (SPM). In this context, the failure of NSAIDs in hypertension treatment seems to be associated with the reduction of endogenous NO bioavailability, which is not necessarily an effect of all drug members of this pharmacological class. For this reason, NO-releasing NSAIDs seem to be safer and more specific therapy to treat vascular inflammation in hypertension than regular NSAIDs.

Importance of circadian timing for aging and longevity

Dietary restriction (DR) decreases body weight, improves health, and extends lifespan. DR can be achieved by controlling how much and/or when food is provided, as well as by adjusting nutritional composition. Because these factors are often combined during DR, it is unclear which are necessary for beneficial effects. Several drugs have been utilized that target nutrient-sensing gene pathways, many of which change expression throughout the day, suggesting that the timing of drug administration is critical. Here, we discuss how dietary and pharmacological interventions promote a healthy lifespan by influencing energy intake and circadian rhythms.

Circadian clocks link physiologic processes to environmental conditions and a mismatch between internal and external rhythms has negative effects on organismal health. In this review, the authors discuss the interactions between circadian clocks and dietary interventions targeted to promote healthy aging.

Circadian Biology and Stroke

Circadian biology modulates almost all aspects of mammalian physiology, disease, and response to therapies. Emerging data suggest that circadian biology may significantly affect the mechanisms of susceptibility, injury, recovery, and the response to therapy in stroke. In this review/perspective, we survey the accumulating literature and attempt to connect molecular, cellular, and physiological pathways in circadian biology to clinical consequences in stroke. Accounting for the complex and multifactorial effects of circadian rhythm may improve translational opportunities for stroke diagnostics and therapeutics.

Accounting for Time: Circadian Rhythms in the Time of COVID-19

The COVID-19 pandemic has necessitated novel approaches and collaborative efforts across multiple disciplines. It is known that various aspects of our physiology and response to pathogens are under tight clock control. However, the assimilation of circadian biology into our clinical and research practices is still evolving. Using a focused review of the literature and original analyses of the UK Biobank, we discuss how circadian biology may inform our diagnostic and therapeutic strategies in this pandemic.

A Systematic Review of the Efficacy and Safety of Aspirin When Delivered at Different Medication Times for the Primary and Secondary Prevention of Cardiovascular and Cerebrovascular Diseases

PURPOSE

Effective antiplatelet therapy can significantly reduce the incidence and mortality rate of cardiovascular and cerebrovascular diseases. Aspirin is widely used in the secondary prevention of cardiovascular and cerebrovascular diseases; however, there is widespread debate as to when patients should take an enteric-coated aspirin tablet on a daily basis. In the present study, we evaluated the efficacy and safety of different aspirin medication times (morning or before bedtime) in terms of the primary and secondary prevention of cardiovascular and cerebrovascular diseases using meta-analysis.

METHODS

Studies with randomized control trials (RCT) or crossover trials regarding to the usage of aspirin (morning or before bedtime) for the primary or secondary prevention of cardiovascular and cerebrovascular diseases were searched in Medline, EMbase, Cochrane Library, CNKI, Wanfang Data, VIP Database and CBM. Review Manager 5 (RevMan 5, v5.3), a Cochrane systematic reviews software, was used to perform meta-analysis based on the recommendation of the Cochrane Handbook for risk assessment tools.

RESULTS

Meta-analysis showed that taking low-dose aspirin tablets before bed reduced systolic and diastolic blood pressure compared with taking it in the morning. At the same time, the number of studies on platelet aggregation rate, C-reactive protein (CRP), serum nitric oxide (NO) or thromboxane B₂ (TXB₂) is too small to be reliable. However, there was a large heterogeneity across the studies. The quality of some studies was not high enough.

CONCLUSION

Additional blood pressure benefits can be achieved by taking aspirin before bedtime, but it does not affect its antiplatelet effect and does not pose a higher risk of bleeding.

Circadian Variation in Efficacy of Medications

Although much has been learned about circadian clocks and rhythms over the past few decades, translation of this foundational science underlying the temporal regulation of physiology and behavior to clinical applications has been slow. Indeed, acceptance of the modern study of circadian rhythms has been blunted because the phenomenology of cyclic changes had to counteract the 20th century dogma of homeostasis in the biological sciences and medicine. We are providing this review of clinical data to highlight the emerging awareness of circadian variation in efficacy of medications for physicians, clinicians, and pharmacists. We are suggesting that gold-standard double-blind clinical studies should be conducted to determine the best time of day for optimal effectiveness of medications; also, we suggest that time of day should be tracked and reported as an important biological variable in ongoing clinical studies hereafter. Furthermore, we emphasize that time of day is, and should be considered, a key biological variable in research design similar to sex. In common with biomedical research data that have been historically strongly skewed toward the male sex, most pharmaceutical data have been skewed toward morning dosing without strong evidence that this is the optimal time of efficacy.

Therapeutics on the clock: Circadian medicine in the treatment of chronic inflammatory diseases

The circadian clock is a collection of endogenous oscillators with a periodicity of ~ 24 h. Recently, our understanding of circadian rhythms and their regulation at genomic and physiologic scales has grown significantly. Knowledge of the circadian influence on biological processes has provided new possibilities for novel pharmacological strategies. Directly targeting the biological clock or its downstream targets, and/or using timing as a variable in drug therapy are now important pharmacological considerations. The circadian machinery mediates many aspects of the inflammatory response and, reciprocally, an inflammatory environment can disrupt circadian rhythms. Therefore, intense interest exists in leveraging circadian biology as a means to treat chronic inflammatory diseases such as sepsis, asthma, rheumatoid arthritis, osteoarthritis, and cardiovascular disease, which all display some type of circadian signature. The purpose of this review is to evaluate the crosstalk between circadian rhythms, inflammatory diseases, and their pharmacological treatment. Evidence suggests that carefully rationalized application of chronotherapy strategies - alone or in combination with small molecule modulators of circadian clock components - can improve efficacy and reduce toxicity, thus warranting further investigation and use.

The impact of acetylsalicylic acid dosed at bedtime on circadian rhythms of blood pressure in the high-risk group of cardiovascular patients-a randomized, controlled trial

Purpose

Time of drug administration may significantly influence its effect. The aim of the present study was to investigate the effect of ASA (administrated in the morning or in the evening) on the anti-hypertensive effect and diurnal blood pressure profile in the high-risk group of cardiovascular patients.

Methods

All patients (n = 114) had been diagnosed with coronary heart disease and arterial hypertension prior to the enrolment and had been treated with 75 mg per day of ASA in the morning. The patients were randomly assigned to one of the two study groups receiving 75 mg of ASA per day in a single antiplatelet therapy for 3 months in the morning (n = 58) or in the evening (n = 56). The control group (n = 61) consisted of patients with arterial hypertension but without coronary heart disease, not receiving ASA. In all the patients, during each visit, clinical blood pressure (BP) and ambulatory blood pressure measurements (ABPM) were performed.

Results

There was a significant reduction in 24-h BP and blood pressure at night in the ASA group evening group compared with the ASA morning group and the control group.

Conclusions

The present study demonstrated that compared with the use of ASA in the morning, its administration in the evening may lead to favourable drop in the ABPM and an improvement of the diurnal profile in the high-risk group of cardiovascular patients who are not naïve to ASA.

Electronic supplementary material

The online version of this article (10.1007/s00228-020-02997-8) contains supplementary material, which is available to authorized users.

Evening aspirin intake results in higher levels of platelet inhibition and a reduction in reticulated platelets - a window of opportunity for patients with cardiovascular disease?

Cardiovascular events occur most frequently in the early morning. Similarly, the release of reticulated platelets (RP) by megakaryocytes has a peak in the late night and early morning. Which aspirin regimen most effectively inhibits platelets during these critical hours is unknown. Hence, the primary objective of this trial was to assess platelet function and RP levels at 8.00 AM, in stable cardiovascular (CVD) patients, during three different aspirin regimens. In this open-label randomized cross-over study subjects were allocated to three sequential aspirin regimens: once-daily (OD) 80 mg morning; OD-evening, and twice-daily (BID) 40 mg. Platelet function was measured at 8.00 AM & 8.00 PM by serum Thromboxane B₂ (sTxB₂) levels, the Platelet Function Analyzer (PFA)-200® Closure Time (CT), Aspirin Reaction Units (ARU, VerifyNow®), and RP levels. In total, 22 patients were included. At 8.00 AM, sTxB₂ levels were the lowest after OD-evening in comparison with OD-morning (p = <0.01), but not in comparison with BID. Furthermore, RP levels were similar at 8.00 AM, but statistically significantly reduced at 8.00 PM after OD-evening (p = .01) and BID (p = .02) in comparison with OD-morning. OD-evening aspirin intake results in higher levels of platelet inhibition during early morning hours and results in a reduction of RP levels in the evening. These findings may, if confirmed by larger studies, be relevant to large groups of patients taking aspirin to reduce cardiovascular risk.

Cardiovascular diseases: a therapeutic perspective around the clock

Biological rhythms are a ubiquitous feature of life. Most bodily functions, including physiological, biochemical, and behavioral processes, are coupled by the circadian rhythm. In the cardiovascular system, circadian fluctuations regulate several functions, namely heart rate, blood pressure, cardiac contractility, and metabolism. In fact, current lifestyles impose external timing constraints that clash with our internal circadian physiology, often increasing the risk of cardiovascular disease (CVD). Still, the mechanisms of dysregulation are not fully understood because this is a growing area of research. In this review, we explore the modulatory role of the circadian rhythms on cardiovascular function and disease as well as the role of chronotherapy in the context of CVD and how such an approach could improve existing therapies and assist in the development of new ones.

Circadian rhythms and the molecular clock in cardiovascular biology and disease

The Earth turns on its axis every 24 h; almost all life on the planet has a mechanism - circadian rhythmicity - to anticipate the daily changes caused by this rotation. The molecular clocks that control circadian rhythms are being revealed as important regulators of physiology and disease. In humans, circadian rhythms have been studied extensively in the cardiovascular system. Many cardiovascular functions, such as endothelial function, thrombus formation, blood pressure and heart rate, are now known to be regulated by the circadian clock. Additionally, the onset of acute myocardial infarction, stroke, arrhythmias and other adverse cardiovascular events show circadian rhythmicity. In this Review, we summarize the role of the circadian clock in all major cardiovascular cell types and organs. Second, we discuss the role of circadian rhythms in cardiovascular physiology and disease. Finally, we postulate how circadian rhythms can serve as a therapeutic target by exploiting or altering molecular time to improve existing therapies and develop novel ones.

Personalized treatment selection using data from crossover designs with carry-over effects

In this work, we propose a semiparametric method for estimating the optimal treatment for a given patient based on individual covariate information for that patient when data from a crossover design are available. Here, we assume there are carry-over effects for patients switching from one treatment to another. For the K treatment (K ≥ 2) scenario, we show that nonparametric estimation of carry-over effects can have the undesirable property that comparison of treatment means can only be done using independent outcome measurements from different groups of patients rather than using available joint measurements for each patient. To overcome this barrier, we compare probabilities of outcome variable of each treatment dominating outcome variables for all other treatments conditional on patient-specific scores constructed from patient covariates. We suggest single-index models as appropriate models connecting outcome variables to covariates and our empirical investigations show that frequencies of correct treatment assignments are highly accurate. The proposed method is also rather robust against departures from a single-index model structure. We also conduct a real data analysis to show the applicability of the proposed procedure.

Aspirin for the prevention and treatment of pre-eclampsia: A matter of COX-1 and/or COX-2 inhibition?

Since the 1970s, we have known that aspirin can reduce the risk of pre‐eclampsia. However, the underlying mechanisms explaining this risk reduction are poorly understood. Both cyclooxygenase (COX)‐1‐ and COX‐2‐dependent effects might be involved. As a consequence of this knowledge hiatus, the optimal dose and timing of initiation of aspirin therapy are not clear. Here, we review how (COX‐1 versus COX‐2 inhibition) and when (prevention versus treatment) aspirin therapy may interfere with the mechanisms implicated in the pathogenesis of pre‐eclampsia. The available evidence suggests that both COX‐1‐ and COX‐2‐dependent effects play important roles in the early stage of aberrant placental development and in the next phase leading to the clinical syndrome of pre‐eclampsia. Collectively, these data suggest that high‐dose (dual COX inhibition) aspirin may be superior to standard low‐dose (selective COX‐1 inhibition) aspirin for the prevention and also treatment of pre‐eclampsia. Therefore, we conclude that more functional and biochemical tests are needed to unravel the contribution of prostanoids in the mechanisms implicated in the pathogenesis of pre‐eclampsia and the potential of dual COX and/or selective COX‐2 inhibition for the prevention and treatment of pre‐eclampsia. This information is vital if we are to deduce the suitability, optimal timing and dose of aspirin and/or a specific COX‐2 inhibitor (most likely using modified forms that do not cross the placenta) that can then be tested in a randomized, controlled trial instead of the current practice of empirical dosing regimens.

Medicine in the Fourth Dimension

The importance of circadian biology has rarely been considered in pre-clinical studies, and even more when translating to the bedside. Circadian biology is becoming a critical factor for improving drug efficacy and diminishing drug toxicity. Indeed, there is emerging evidence showing that some drugs are more effective at nighttime than daytime, whereas for others it is the opposite. This suggests that the biology of the target cell will determine how an organ will respond to a drug at a specific time of the day, thus modulating pharmacodynamics. Thus, it is now time that circadian factors become an integral part of translational research.

Circadian Rhythm of Cardiovascular Disease: The Potential of Chronotherapy With Aspirin

Almost all the systems in our body adhere to a daily 24 h rhythm. The cardiovascular system is also affected by this 24 h rhythm. In the morning there is a change in various cardiovascular processes, including platelet aggregability. These changes may play a role in the relative excess of early morning cardiovascular events. The number of recurrent cardiovascular diseases (CVD) could, in theory, be reduced by responding to this 24 h rhythm with timed medication intake (chronotherapy), which also applies to aspirin. Multiple studies on chronotherapy with low-dose aspirin are promising, showing a decrease in early morning platelet activity with evening intake compared with morning intake. However, in order to further demonstrate its clinical impact, randomized trials with cardiovascular events as a primary outcome are needed. This review discusses the available evidence of the effects of circadian rhythm on CVD and the potential positive effect of chronotherapy with aspirin.

Embolic stroke of undetermined source (ESUS) cohort of Brazilian patients in a university hospital

OBJECTIVE

Embolic stroke of undetermined source (ESUS) is an important group of cryptogenic strokes that are in evidence due recent ongoing trials. We reviewed medical records at discharge from the stroke unit of all patients who met ESUS criteria and attended our institution between February 2016 and July 2017. Among 550 stroke patients, 51 had ESUS. We found that hypertension (60%), diabetes mellitus (34%), and smoking (36%) were the most prevalent risk factors. The mean National Institutes of Health Stroke Scale (NIHSS) scores were 7 at admission and 4 at discharge, while median scores on the modified Rankin scale were 0 and 2 at admission and discharge, respectively. Our sample had similar ages, risk factors prevalence and NIHSS scores at admission and discharge when compared with European and North American cohorts. Although a small cohort, our study suggests that the ESUS population is similar in countries with different health financing.

Time-Dependent Hypotensive Effect of Aspirin in Mice

Objective- Evening but not morning administration of low-dose aspirin has been reported to lower blood pressure in hypertensive patients. The present study was designed to determine whether this phenomenon could be replicated in mice, and if so, whether a time-dependent effect of aspirin on blood pressure was because of alteration of circadian clock function. Approach and Results- We recapitulated the protective effect of aspirin (50 μg/d for 7 days) at zeitgeber time 0 (active-to-rest transit), but not at zeitgeber time 12, on a high-salt diet-induced increase of blood pressure. However, the time of aspirin administration did not influence expression of canonical clock genes or their acetylation. We used mouse Bmal1 and Per2-luciferase reporters expressed in U2OS cells to determine the real-time effect of aspirin on circadian function but found that the oscillation of bioluminescence was unaltered. Timing of aspirin administration also failed to alter urinary prostaglandin metabolites or catecholamines, or the acetylation of its COX-1 (cyclooxygenase-1) target in platelets. Conclusions- The time-dependent hypotensive effect of aspirin in humans has been recapitulated in hypertensive mice. However, this does not seem to reflect a direct impact of aspirin on circadian clocks or on acetylation of platelet COX-1.

The effect of acetylsalicylic acid dosed at bedtime on the anti-aggregation effect in patients with coronary heart disease and arterial hypertension: A randomized, controlled trial

BACKGROUND

Acetylsalicylic acid (ASA) is one of the basic drugs used in the secondary prevention of coronary artery disease (CAD), and in most cases it is taken in the morning in one daily dose. It is suggested that the morning peak of platelet aggregation is responsible for the occurrence of myocardial infarctions and strokes. Hence, the aim of the study was to observe the effect of ASA (morning vs. evening) dosing on the anti-aggregative effect of platelets in patients with CAD and arterial hypertension (AH).

METHODS

The study involved 175 patients with CAD and AH. Patients were randomly assigned to one of two study groups, taking ASA in the morning or in the evening. The patients had two visits, one baseline and another after 3 months from changing the time of ASA dosage. The platelet aggregation was determined using the VerifyNow analyzer.

RESULTS

In the ASA evening group, a significant reduction in platelet aggregation was obtained. In the ASA morning group, a significant difference in response to ASA was observed, depending on sex. In men, the reactivity of platelets decreased, but in women it increased.

CONCLUSIONS

In the group of patients with CAD and AH, bedtime ASA dosing is associated with a significant reduction in platelet aggregation. The response to ASA may differ between sexes. The benefit gained by changing the drug administration from the morning to the evening is greater in women.

Chronotherapy for Hypertension

PURPOSE OF REVIEW

Given the emerging knowledge that circadian rhythmicity exists in every cell and all organ systems, there is increasing interest in the possible benefits of chronotherapy for many diseases. There is a well-documented 24-h pattern of blood pressure with a morning surge that may contribute to the observed morning increase in adverse cardiovascular events. Historically, antihypertensive therapy involves morning doses, usually aimed at reducing daytime blood pressure surges, but an absence of nocturnal dipping blood pressure is also associated with increased cardiovascular risk.

RECENT FINDINGS

To more effectively reduce nocturnal blood pressure and still counteract the morning surge in blood pressure, a number of studies have examined moving one or more antihypertensives from morning to bedtime dosing. More recently, such studies of chronotherapy have studied comorbid populations including obstructive sleep apnea, chronic kidney disease, or diabetes. Here, we summarize major findings from recent research in this area (2013-2017). In general, nighttime administration of antihypertensives improved overall 24-h blood pressure profiles regardless of disease comorbidity. However, inconsistencies between studies suggest a need for more prospective randomized controlled trials with sufficient statistical power. In addition, experimental studies to ascertain mechanisms by which chronotherapy is beneficial could aid drug design and guidelines for timed administration.

Evaluation of the antihypertensive effect of nocturnal administration of acetylsalicylic acid: a cross-over randomized clinical trial

OBJECTIVE

Several studies have shown that evening intake of aspirin has antihypertensive effect in healthy adults, which has not been proven in patients with cardiovascular disease, who mostly take aspirin in the morning. We have evaluated the antihypertensive effect of bedtime administration of aspirin in patients with cardiovascular disease already treated for hypertension.

METHODS

This is a multicenter randomized triple-blind placebo-controlled crossover trial, with hypertensive patients treated with aspirin for secondary prevention. There was a baseline-randomized assignment to 2-month periods of bedtime aspirin (100 mg) first and morning-time aspirin later, or inversely, both periods separated by an open label 2-4 weeks period of morning-time aspirin. At the start and end of each treatment period, a 24-h ambulatory blood pressure monitoring was performed. The main outcome measure was mean 24-h blood pressure. The analyses were performed according to the intention-to-treat principle.

RESULTS

Overall, 225 patients were randomized. No significant differences were observed in ambulatory blood pressure by time of intake of usual low doses of aspirin. The mean SBP/DBP was 123.2/69.9 (95% CI 121.58-124.9/68.86-76.86) with bedtime administration and 122.4/68.8 (95% CI 120.76-124.01/67.85-69.83) with daytime administration (P = 0.3 and P = 0.23 for SBP and DBP, respectively).

CONCLUSION

Administering aspirin at bedtime rather than in the morning does not modify the 24-h ambulatory blood pressure in hypertensive patients in secondary cardiovascular prevention.The trial was registered with ClinicalTrials.gov (number NCT01741922).

Does the timing of aspirin administration influence its antiplatelet effect - review of literature on chronotherapy

This publication is a summary of the multidirectional effects of aspirin and its role in modern medicine. The history of aspirin, or acetylsalicylic acid (ASA), and its use dates back to ancient times, although the substance in its pure form has been produced and sold since 1899. Initially it was used for its antipyretic, analgesic, and anti-inflammatory effects. Over the years many other benefits associated with the administration of ASA have been revealed. The mechanism of aspirin’s action was discovered thanks to the British pharmacologist and Nobel Prize winner Sir John Vane. Understanding the effects of acetylsalicylic acid, associated with the inhibition of cyclooxygenase and proinflammatory thromboxane A2 and with increased concentration of vasoprotective, antithrombotic prostacyclin, gave rise to the era of using small “cardiac” doses of ASA in cardiovascular diseases. In addition to the well-researched antiplatelet effect, other properties of ASA have been discovered, such as the non-COX-1 dependent improvement of endothelial function or the hypotensive effect after evening administration. According to the currently available knowledge, it is possible to speak of a pleiotropic effect of ASA and its use in the prevention of cardiovascular diseases, taking into account its anti-aggregation effect, circadian rhythms, and the principles of chronotherapy.

Altered Circadian Timing System-Mediated Non-Dipping Pattern of Blood Pressure and Associated Cardiovascular Disorders in Metabolic and Kidney Diseases

The morning surge in blood pressure (BP) coincides with increased cardiovascular (CV) events. This strongly suggests that an altered circadian rhythm of BP plays a crucial role in the development of CV disease (CVD). A disrupted circadian rhythm of BP, such as the non-dipping type of hypertension (i.e., absence of nocturnal BP decline), is frequently observed in metabolic disorders and chronic kidney disease (CKD). The circadian timing system, controlled by the central clock in the suprachiasmatic nucleus of the hypothalamus and/or by peripheral clocks in the heart, vasculature, and kidneys, modulates the 24 h oscillation of BP. However, little information is available regarding the molecular and cellular mechanisms of an altered circadian timing system-mediated disrupted dipping pattern of BP in metabolic disorders and CKD that can lead to the development of CV events. A more thorough understanding of this pathogenesis could provide novel therapeutic strategies for the management of CVD. This short review will address our and others' recent findings on the molecular mechanisms that may affect the dipping pattern of BP in metabolic dysfunction and kidney disease and its association with CV disorders.

Aspirin and blood pressure: Effects when used alone or in combination with antihypertensive drugs

Arterial hypertension is a major risk factor for cardiovascular and renal events. Lowering blood pressure is thus an important strategy for reducing morbidity and mortality. Since low-dose aspirin is a cornerstone in the prevention of adverse cardiovascular outcomes, combined treatment with aspirin and antihypertensive drugs is very common. However, the impact of aspirin therapy on blood pressure control remains a subject of intense debate. Recent data suggest that the cardioprotective action of aspirin extends beyond its well-known antithrombotic effect. Aspirin has been shown to trigger the synthesis of specialized pro-resolving lipid mediators from arachidonic acid and omega-3 fatty acids. These novel anti-inflammatory and pro-resolving mediators actively stimulate the resolution of inflammation and tissue regeneration. Additionally, they may contribute to other protective effects on redox status and vascular reactivity that have also been attributed to aspirin. Of note, aspirin has been shown to improve vasodilation through cyclooxygenase-independent mechanisms. On the other hand, higher aspirin doses have been reported to exert a negative impact on blood pressure due to inhibition of cyclooxygenase-2 activity, which reduces renal blood flow, glomerular filtration rate and sodium and water excretion. This review aims to provide an overview of the effects of aspirin on blood pressure and the underlying mechanisms, focusing on the interaction between aspirin and antihypertensive drugs. Studies in both experimental and human hypertension are presented.

Wake-Up Stroke: Current Understanding

Patients with wake-up strokes account for approximately 1 in 5 individuals presenting with an acute ischemic stroke. However, they are commonly excluded from acute stroke treatment. This article reviews the current understanding of wake-up strokes. A comparison of wake-up and awake-onset strokes demonstrated that they are physiologically, clinically, and radiologically similar. Use of advanced CT and MRI techniques may help extend acute stroke treatment options to patients with wake-up stroke.

The Circadian System: A Regulatory Feedback Network of Periphery and Brain

Circadian rhythms are generated by the autonomous circadian clock, the suprachiasmatic nucleus (SCN), and clock genes that are present in all tissues. The SCN times these peripheral clocks, as well as behavioral and physiological processes. Recent studies show that frequent violations of conditions set by our biological clock, such as shift work, jet lag, sleep deprivation, or simply eating at the wrong time of the day, may have deleterious effects on health. This infringement, also known as circadian desynchronization, is associated with chronic diseases like diabetes, hypertension, cancer, and psychiatric disorders. In this review, we will evaluate evidence that these diseases stem from the need of the SCN for peripheral feedback to fine-tune its output and adjust physiological processes to the requirements of the moment. This feedback can vary from neuronal or hormonal signals from the liver to changes in blood pressure. Desynchronization renders the circadian network dysfunctional, resulting in a breakdown of many functions driven by the SCN, disrupting core clock rhythms in the periphery and disorganizing cellular processes that are normally driven by the synchrony between behavior and peripheral signals with neuronal and humoral output of the hypothalamus. Consequently, we propose that the loss of synchrony between the different elements of this circadian network as may occur during shiftwork and jet lag is the reason for the occurrence of health problems.