Mechanisms underlying the morning increase in platelet aggregation: a flow cytometry study

Stroke in the Time of Circadian Medicine

Time-of-day significantly influences the severity and incidence of stroke. Evidence has emerged not only for circadian governance over stroke risk factors, but also for important determinants of clinical outcome. In this review, we provide a comprehensive overview of the interplay between chronobiology and cerebrovascular disease. We discuss circadian regulation of pathophysiological mechanisms underlying stroke onset or tolerance as well as in vascular dementia. This includes cell death mechanisms, metabolism, mitochondrial function, and inflammation/immunity. Furthermore, we present clinical evidence supporting the link between disrupted circadian rhythms and increased susceptibility to stroke and dementia. We propose that circadian regulation of biochemical and physiological pathways in the brain increase susceptibility to damage after stroke in sleep and attenuate treatment effectiveness during the active phase. This review underscores the importance of considering circadian biology for understanding the pathology and treatment choice for stroke and vascular dementia and speculates that considering a patient's chronotype may be an important factor in developing precision treatment following stroke.

N-methyl-D-aspartate receptor regulates the circadian clock in megakaryocytic cells and impacts cell proliferation through BMAL1

Peripheral circadian clocks control cell proliferation and survival, but little is known about their role and regulation in megakaryocytic cells. N-methyl-D-aspartate receptor (NMDAR) regulates the central clock in the brain. The purpose of this study was to determine whether NMDAR regulates the megakaryocytic cell clock and whether the megakaryocytic clock regulates cell proliferation and cell death. We found that both the Meg-01 megakaryocytic cell line and native murine megakaryocytes expressed circadian clock genes. Megakaryocyte-directed deletion of Grin1 in mice caused significant disruption of the circadian rhythm pathway at the transcriptional level and increased expression of BMAL1 at the protein level. Similarly, both pharmacological (MK-801) and genetic (GRIN-/-) inhibition of NMDAR in Meg-01 cells in vitro resulted in widespread changes in clock gene expression including increased expression of BMAL1, the core clock transcription factor. BMAL1 overexpression reduced Meg-01 cell proliferation and altered the time-dependent expression of the cell cycle regulators MYC and WEE1, whereas BMAL1 knockdown led to increased cell death in Meg-01-GRIN1-/- cells. Our results demonstrate that NMDAR regulates the circadian clock in megakaryocytic cells and that the circadian clock component BMAL1 contributes to the control of Meg-01 cell proliferation and survival.

The relationship between the systemic immune-inflammation index and reverse-dipper circadian pattern in newly diagnosed hypertensive patients

Although hypertension is considered high intravascular pressure, impairing circadian blood pressure (BP) has been shown to potentially contribute to poor clinical outcomes. Systemic immune-inflammation index (SII), based on platelet, neutrophil, and lymphocyte counts, has been established as a strong prognostic marker in cardiovascular disease. The role of inflammation in the pathogenesis of hypertension is a well-known issue and inflammatory markers are associated with BP variability. We aimed to investigate whether there is a relationship between circadian BP changes and SII in newly diagnosed hypertensive patients. The study population consisted of 196 newly diagnosed hypertensive patients without LVH. In total, 76 (38%) patients had a dipper BP pattern, 60 (31%) patients had a non-dipper BP pattern, and 60 (31%) patients had a reverse-dipper BP pattern. SII was calculated according to Multivariate logistic regression analysis revealed SII and HDL-C as an independent predictors of reverse-dipper circadian pattern in newly diagnosed hypertensive patients. The cut-off value of the SII for reverse-dipper hypertension in a ROC curve analysis was >639.73 with 63.3% sensitivity and 84.2% specificity. Our study showed that the SII level was higher in the reverse-dipper hypertension patient group than in the dipper and non-dipper hypertension groups. Furthermore, SII was an independent predictor of newly diagnosed reverse-dipper hypertensive patients. The high SII value in newly diagnosed hypertensive patients can be used as an early warning parameter to identify reverse-dipper hypertension patients.

Revascularization of acute stent thrombosis caused by diarrhea after carotid artery stenting in an intermediate clopidogrel metabolizer

Carotid artery stenting (CAS) is an alternative treatment to carotid endarterectomy for carotid artery stenosis. Acute stent thrombosis (ACST) is an extremely rare complication but can have devastating consequences. Although many cases have been reported, the best treatment is still uncertain. In this study, we report the treatment of ACST caused by diarrhea in an intermediate clopidogrel metabolizer. We also review the literature and discuss appropriate treatment strategies for this rare event.

A prospective study of wake-up stroke patients presenting to the emergency department: a single-center cohort study

INTRODUCTION

This study aims to prospectively examine patients with ischemic wake-up stroke (WUS) presenting to the emergency department, to investigate the risk factors affecting the mortality occurring within 28, 90, and 180 days, and to create a new scoring system for the prediction of 28-day mortality.

MATERIALS AND METHOD

Patients who presented to the emergency department with WUS findings between 01.07.2019 and 30.06.2020 were prospectively analyzed. Logistic regression analysis was performed to determine the factors affecting mortality and the modified Rankin scale (mRS).

RESULTS

A total of 161 patients were included. Of the patients, 22.4% died within 28 days and 40.4% within 180 days. The presence of coronary artery disease (CAD) increased the 28-day mortality risk (p = 0.009) 3.57 times, 90-day mortality risk 2.15 times (p = 0.033), and 180-day mortality risk 2.18 times (p = 0.045). In order to be used in the prediction of 28-day mortality in patients with WUS, we developed the ischemic WUS mortality score (IWUSMOS), which consists of the middle cerebral artery (45 points), internal carotid artery (60 points), basilar artery (39 points), superior cerebellar artery (66 points) occlusion, hypertension (33 points), CAD (28 points), malignancy (100 points), and arrhythmia (23 points). With this scoring system, the 28-day mortality risk was determined as 0.05% when the total score was "43" whereas the mortality risk was found to be 95.0% when the total score was "187."

CONCLUSION

We propose that IWUSMOS, a new scoring system, can be used to predict the 28-day mortality risk of patients with WUS.

Home-measured pulse pressure is a predictor of cardiovascular disease in type 2 diabetes: The KAMOGAWA-HBP study

BACKGROUND AND AIMS

Pulse pressure (PP) is a prognostic predictor of cardiovascular mortality. This retrospective cohort study aimed to investigate the association between home PP measurements and cardiovascular disease in patients with type 2 diabetes.

METHODS AND RESULTS

Home blood pressure was measured for 14 consecutive days in 1082 patients with type 2 diabetes, and pulse pressure was calculated. A 10 mmHg increase in morning PP was associated with a 1.30-fold increase in the risk of cardiovascular disease. The risk of cardiovascular disease was 1.88 times higher in the morning in the higher PP group than in the lower PP group. In the receiver operating characteristic analysis, the areas under the curve (95% confidence interval) corresponding to the PP (morning, evening, and clinic) for new-onset cardiovascular disease were 0.63 (0.58-0.69), 0.62 (0.57-0.67), and 0.59 (0.54-0.64), respectively. The area under the curve for PP measured in the morning was significantly greater than that for PP measured in the clinic (P = 0.032).

CONCLUSION

Home-measured PP is a better predictor of new-onset cardiovascular disease than clinic-measured PP, in patients with type 2 diabetes.

Circadian rhythms in ischaemic heart disease: key aspects for preclinical and translational research: position paper of the ESC working group on cellular biology of the heart

Circadian rhythms are internal regulatory processes controlled by molecular clocks present in essentially every mammalian organ that temporally regulate major physiological functions. In the cardiovascular system, the circadian clock governs heart rate, blood pressure, cardiac metabolism, contractility, and coagulation. Recent experimental and clinical studies highlight the possible importance of circadian rhythms in the pathophysiology, outcome, or treatment success of cardiovascular disease, including ischaemic heart disease. Disturbances in circadian rhythms are associated with increased cardiovascular risk and worsen outcome. Therefore, it is important to consider circadian rhythms as a key research parameter to better understand cardiac physiology/pathology, and to improve the chances of translation and efficacy of cardiac therapies, including those for ischaemic heart disease. The aim of this Position Paper by the European Society of Cardiology Working Group Cellular Biology of the Heart is to highlight key aspects of circadian rhythms to consider for improvement of preclinical and translational studies related to ischaemic heart disease and cardioprotection. Applying these considerations to future studies may increase the potential for better translation of new treatments into successful clinical outcomes.

Stroke: What's Sleep Got to Do With It?

SUMMARY

Ischemic strokes most often occur between 6 am and 12 am after awakening from sleep but up to 30% occur during sleep. Wake-up strokes (WUS) are new focal neurological deficit(s) persisting for ≥ 24 hours attributable to an ischemic event present on patient awakening. Obstructive sleep apnea (OSA) is a major risk factor for WUS because it compounds the instability of the morning environment and increases the likelihood of cardiovascular events, including hypertension, atrial fibrillation, right-to-left shunts, and stroke. Circadian-driven alterations in structural, homeostatic, and serological factors also predispose to WUS. Also, WUS patients are often not considered candidates for time-dependent intravenous thrombolysis therapy because of an uncertain onset time. However, using the tissue clock (positive diffusion weighted imaging-negative fluid-attenuated inversion recovery mismatch) dates the WUS as 3 to 4.5 hours old and permits consideration for intravenous thrombolysis and if needed mechanical thrombectomy. Given the high prevalence of moderate/severe OSA in stroke patients and its impact on stroke outcomes, screening with overnight pulse oximetry and home sleep apnea test is needed. Treating OSA poststroke remains challenging. Polysomnographic changes in sleep architecture following acute/subacute stroke may also impact upon stroke outcome.

Mouth opening/breathing is common in sleep apnea and linked to more nocturnal water loss

OBJECTIVES

Mouth opening/breathing during sleep is common in patients with obstructive sleep apnea (OSA), which is probably associated with more water loss and higher risk for nocturnal ischemic heart attack. This study aimed to evaluate nocturnal changes in hematocrit/hemoglobin levels and estimated plasma volume loss in OSA patients and its relation to their OSA severity and mouth open/breathing.

METHODS

Sixty OSA patients and fifteen healthy controls were enrolled and underwent overnight polysomnography. Mouth status was evaluated via an infrared camera and nasal/mouth airflow. Hematocrit and hemoglobin levels in peripheral venous blood were measured before and after sleep to estimate the change of plasma volume.

RESULTS

Compared to controls, OSA patients had a greater nocturnal increase in hematocrit (1.35% vs. 1.0%, p=0.013), hemoglobin (0.50% vs. 0.30%, p=0.002) and more estimated water loss (5.5% vs 3.7% of plasma volume, p<0.013). The extent of increase was correlated to apnea-hypopnea index_the marker of OSA severity (Spearman's ρ=0.332, p=0.004; ρ=0.367, p=0.001 for hematocrit, hemoglobin, respectively), which remained significant after serial multivariate adjustment. OSA patients had more sleep time with mouth open (96.7% vs 26.7% of total sleep time, p<0.001) and time with complete mouth breathing (14.1% vs 2.7%, p<0.001). The extent of mouth breathing was correlated to apnea-hypopnea index (ρ=0.487, p<0.001), nocturnal increase in hematocrit/hemoglobin levels (ρ=0.236, p=0.042; ρ=0.304, p=0.008, respectively) and estimated plasma volume loss (ρ=0.262, p=0.023).

CONCLUSIONS

OSA patients had a greater increase in hematocrit/hemoglobin levels after sleep, which is probably linked to more water loss and more sleep time with mouth open/breathing.

Restrictive type and infectious complications might predict nadir hematological values among individuals with anorexia nervosa during the refeeding period: a retrospective study

BACKGROUND

Although hematological abnormalities in patients with anorexia nervosa have been documented, the mechanisms involved have not been fully clarified, especially during the refeeding period when hematological values further decrease after admission prior to improving. Here we address potential mechanisms underlying the hematological abnormalities of inpatients with anorexia nervosa during the refeeding period.

METHODS

We recruited patients from 101 admissions corresponding to 55 individual patients with anorexia nervosa with severe malnutrition (body mass index, 13.4 ± 3.4) from the neuropsychiatry unit in Ashikaga Red Cross Hospital during the period from October 1999 to March 2018. We analyzed three hematological cell measures, i.e., hemoglobin, white cell count, and platelet count, to determine their levels at admission and their lowest levels during the refeeding period and calculated the percent decrease in those values from admission to the nadir levels. We analyzed each measure using a general mixed model with explanatory variables, including data upon admission and a treatment-related indicator, i.e., energy intake.

RESULTS

The initial hemoglobin value of 12.1 ± 2.7 g/dl decreased by 22.3% to 9.4 ± 2.5 g/dl; the initial white cell count was 5387 ± 3474/μl, which decreased by 33.6% to 3576 ± 1440/μl; the initial platelet count of 226 ± 101 × 10³/μl decreased by 24.3% to 171 ± 80 × 10³/μl. All nadir levels were observed during the refeeding period from the fifth to tenth day of hospitalization. Significant correlations among the three hematological cell measures, particularly at the nadir levels, were found. Of note, 41.7% of our patients who received red blood cell transfusion during hospitalization showed normal hemoglobin levels upon admission. The anorexia nervosa restrictive type was associated with a lower nadir level of white blood cell count. Infectious complications were related to a lower nadir level of hemoglobin and a greater percent decrease in hemoglobin level as well as to the need for red blood cell transfusion.

CONCLUSIONS

Nadir hematological cell measures of inpatients with anorexia nervosa might be predicted by the restrictive type and infectious complications. The anorexia nervosa restrictive type was associated with further decrease in hematological values during the refeeding period.

Can Systemic Immune-Inflammation Index Detect the Presence of Exxaggerated Morning Blood Pressure Surge in Newly Diagnosed Treatment-Naive Hypertensive Patients?

Background: The exaggerated morning blood pressure surge (MS) is associated with target organ damage and cardiovascular events. Systemic immune-inflammation index (SII) has been detected as a useful marker in tumors and cardiovascular diseases. The role of inflammation in the pathogenesis of hypertension is a well-known issue. We aimed to investigate whether there is an association between SII and exaggerated MS in newly diagnosed treatment-naive hypertensive patients.Material and Methods: In total, 343 newly diagnosed in clinical and 24-h ambulatory blood pressure (BP) monitoring treatment-naive hypertensive patients were included in this study. Morning surge was defined as the difference between morning BP, which was the mean of BP during 2 h after wake-up, and the lowest BP, which was the mean of three lowest BP during nighttime. A cutoff value of 52.1 mmHg was used to discriminate the high- and low value MS groups. SII was calculated based on neutrophil, platelet, and lymphocyte counts.Results: Neutrophil, platelet, SII, neutrophil to lymphocyte ratio (NLR), platelet to lymphocyte ratio (PLR) were higher, whereas lymphocyte counts were lower in the high-value MS than the low-value MS. These indices were all independently associated with exaggerated MS and SII was superior to all other indices for detecting the presence of exaggerated MS. SII was moderately correlated with morning BP surge (r: 0.489, p < 0.0001).Conclusion: SII was higher in patients with exaggerated MS and was independently associated with exaggerated MS. Furthermore, SII might be a better indicator than platelet, neutrophil, lymphocyte, NLR, and PLR for the presence of exaggerated MS.

Wake-up strokes are linked to obstructive sleep apnea and worse early functional outcome

BACKGROUND AND AIMS

Presence of sleep-disordered breathing (SDB) and especially obstructive sleep apnea (OSA) is a known risk factor for ischemic stroke. Additionally, SDB effects negatively on recovery after stroke. Up to one fourth of strokes are present on awakening. The link between OSA and wake-up stroke (WUS) has been suggested. We aim to determine the association between OSA and WUS in a Finnish stroke unit cohort.

MATERIAL AND METHODS

An observational prospective longitudinal study consisted of 95 TIA (transient ischemic attack) and mild to moderate stroke patients referred to a Stroke Unit in Finland. Respiratory polygraphy was performed within 72 h of hospital admission. Patients were classified into WUS and non-WUS, and functional outcome measures (mRS, rehabilitation, hospitalization time) were collected. Functional outcomes and prevalence of OSA were compared between non-WUS and WUS.

RESULTS

OSA (AHI > 15/h) was more frequent among WUS than non-WUS (71% and 36%, respectively, p = 0.009). Functional outcome measured with mRS was worse in patients with WUS than non-WUS on registration day and at hospital discharge (p = 0.001). Need for rehabilitation in WUS was 43% of cases compared to 23% of non-WUS (p = 0.067). Hospitalization time was longer (5-15days) in 55% of WUS and 41% of non-WUS patients (p = 0.261).

CONCLUSION

Moderate-to-severe OSA is related to WUS compared to non-WUS. In addition, WUS have worse short-term outcomes measured in mRS. Further studies are needed to determine if OSA is causally linked to WUS.

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.

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.

Safety and efficacy of intravenous thrombolytic treatment in wake-up stroke: Experiences from a single center

OBJECTIVES

Wake-up stroke is an important clinical problem that may account for a quarter of all ischemic strokes. This study aimed to establish the safety and efficacy of intravenous thrombolytic treatment of wake-up strokes by comparing it to the standard thrombolysis treatment in strokes with clear onsets and wake-up strokes that did not receive reperfusion therapy.

METHODS

This retrospective study enrolled 95 patients with ischemic strokes who underwent thrombolytic treatment with alteplase, including nine patients with wake-up strokes. The safety profile (mortality and intracranial bleeding) and efficacy (clinical and functional outcomes on admission, discharge, and 90 days after stroke onset) were evaluated.

RESULTS

When assessed using the modified Rankin scale (mRs), the patients with wake-up strokes had significantly more favorable functional outcomes on discharge when compared to those who received standard thrombolysis (p = .0289). No significant differences were noted when the favorable outcome rate (mRs score = 0-2) at three months post-thrombolysis (Odds ratio [OR] = 2.07; 95% confidence interval [CI] = 0.41-10.6; p = .3807) and safety outcomes (death during hospitalization: OR = 0.49; 95% CI = 0.03-9.11; p = .6295 and intracranial bleeding 24 hr after treatment: OR = 0.43; 95% CI = 0.02-7.58; p = .5707) were compared between the two groups. The Cochran-Mantel-Haenchel shift analysis showed a significantly more favorable distribution of the mRs scores at three months after the stroke onset in the patients with wake-up strokes who were treated with alteplase compared to those who did not receive thrombolysis (OR = 1.42; 95% CI = 1.01-1.82; p = .0426).

CONCLUSIONS

Our study demonstrated that in patients who awaken with stroke symptoms, intravenous thrombolytic treatment is a safe procedure that may lead to favorable outcomes. Further studies should be performed to increase the size of the group of patients with wake-up strokes who can be treated with reperfusion therapy.

Circadian variation and seasonal distribution of implantable defibrillator detected new onset atrial fibrillation

BACKGROUND

We aimed to characterize the hourly, daily, and seasonally variations in the detection of new atrial fibrillation (AF) in heart failure patients implanted with a defibrillator.

METHODS

In 1309 patients enrolled in MADIT-RIT without AF at baseline, atrial arrhythmia data were analyzed from device interrogations. The circadian, weekly, and seasonal distribution of device detected AF was evaluated. The morning period was defined as 06:00-11:59, afternoon as 12:00-16:59, evening as 17:00-22:59, and the nighttime as 23:00-05:59.

RESULTS

During 17 months of follow-up, 66 (5%) patients developed new device-detected AF. AF patients were less likely to have ischemic cardiomyopathy and were more likely to have received an implantable cardioverter defibrillator rather than a cardiac resynchronization therapy with defibrillator. The highest number of AF occurred during the evening hours (25 patients [38%]) followed by a second peak in AF detection during the afternoon hours (21 patients [32%]). Importantly during the nighttime, new AF occurred only in three patients (4%). In comparison with the nighttime period, the odds ratio (OR) of developing AF during the evening time period was 8.5-fold higher (95% CI 7.3-9.7, P < .01). Detection of AF during the spring and winter seasons accounted for 67% of all new device-detected AF.

CONCLUSIONS

There is diurnal and seasonal variation in new onset AF. A double peak in the incidence of AF is observed during the afternoon and evening hours, and during the spring and winter seasons. This information may be useful when deciding when to screen at-risk patients for new AF.

Pathophysiologic mechanisms, neuroimaging and treatment in wake-up stroke

Wake-up stroke (WUS) or ischemic stroke occurring during sleep accounts for 14%-29.6% of all ischemic strokes. Management of WUS is complicated by its narrow therapeutic time window and attributable risk factors, which can affect the safety and efficacy of administering intravenous (IV) tissue plasminogen activator (t-PA). This manuscript will review risk factors of WUS, with a focus on obstructive sleep apnea, potential mechanisms of WUS, and evaluate studies assessing safety and efficacy of IV t-PA treatment in WUS patients guided by neuroimaging to estimate time of symptom onset. The authors used PubMed (1966 to March 2018) to search for the term "Wake-Up Stroke" cross-referenced with "pathophysiology," ''pathogenesis," "pathology," "magnetic resonance imaging," "obstructive sleep apnea," or "treatment." English language Papers were reviewed. Also reviewed were pertinent papers from the reference list of the above-matched manuscripts. Studies that focused only on acute Strokes with known-onset of symptoms were not reviewed. Literature showed several potential risk factors associated with increased risk of WUS. Although the onset of WUS is unknown, a few studies investigated the potential benefit of magnetic resonance imaging (MRI) in estimating the age of onset which encouraged conducting clinical trials assessing the efficacy of MRI-guided thrombolytic therapy in WUS.

Increased Hemoglobin and Plateletcrit Levels Indicating Hemoconcentration in Pediatric Patients with Migraine

INTRODUCTION

Fluid intake was reported to reduce migraine attacks. This may be due to its effect on hemoconcentration. Hemoconcentration may manifest itself by increasing in the hemoglobin and platelet-related values. This study aimed to reveal hemoconcentration by evaluating complete blood cell counts in attack-free periods of pediatric patients with migraine.

MATERIALS AND METHODS

Consecutive children with migraine (n = 70) and tension-type headache (TTH) (n = 65) were compared with the control groups. Control 1 (n = 70) and control 2 (n = 60) groups consisted of age- and gender-matched patients, respectively. Control 2 group patients had gastrointestinal symptoms leading to fluid loss, which may have caused hemoconcentration. To evaluate hemoglobin and platelets together, the M1-value was created by multiplying hemoglobin level by plateletcrit.

RESULTS

The M1-value was higher in the migraine group than in control 1 and TTH groups (P = 0.017 and 0.034) and the hemoglobin and hematocrit levels were also higher in the migraine group than in control 2 group (P = 0.013 and 0.012). Female patients with migraine had higher hemoglobin levels as compared to the female patients in control group 1 (P = 0.041). Male patients with migraine had higher M1-values than the male patients in control group 1 (P = 0.034). In the subgroup of migraine with aura (n = 10), folic acid was significantly lower than the other patients with migraine (P = 0.02).

CONCLUSION

This study suggests that migraine may be accompanied with hemoconcentration in children.

Effects of non-linear resistance training and curcumin supplementation on the liver biochemical markers levels and structure in older women with non-alcoholic fatty liver disease

BACKGROUND

With increasing age, non-alcoholic fatty liver disease is very common among women with low levels of physical activity. Nonlinear resistance training is one of the new methods to help patients who have low levels of physical activity. Curcumin is an herbal supplement that has anti-inflammatory effects. The present study aimed to examine the effects of nonlinear resistance training and curcumin supplementation on the liver structure and biochemical markers in obese older women with non-alcoholic fatty liver disease.

METHODS

Forty-five obese women with non-alcoholic fatty liver disease were randomly assigned into resistance training (RT), curcumin supplement (C), resistance training with curcumin supplement (RTC), and placebo (P) groups. The RT and RTC groups received 12-weeks of nonlinear resistance training while the C and P groups had a normal sedentary lifestyle. Daily, the C and RTC groups received a curcumin capsule while the P and RT groups were given a placebo capsule. Blood sampling and ultrasonography were taken before and after the protocol.

RESULTS

Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels significantly decreased in the RT and RTC groups (P ≤ 0.05) but not in the C and P groups (P > 0.05). Alkaline phosphatase (ALP), total bilirubin (TB) levels, platelet counts (PLT), and liver structure did not significantly change in all groups (P > 0.05). Resistance training alone and with curcumin supplementation could significantly improve liver function while taking curcumin alone did not have any significant effect on it.

CONCLUSION

12-week non-linear resistance training has beneficial effects on non-alcoholic fatty liver disease in older obese women.

Neuroimaging Paradigms to Identify Patients for Reperfusion Therapy in Stroke of Unknown Onset

Despite the proven efficacy of intravenous alteplase or endovascular thrombectomy for the treatment of patients with acute ischemic stroke, only a minority receive these treatments. This low treatment rate is due in large part to delay in hospital arrival or uncertainty as to the exact time of onset of ischemic stroke, which renders patients outside the current guideline-recommended window of eligibility for receiving these therapeutics. However, recent pivotal clinical trials of late-window thrombectomy now force us to rethink the value of a simplistic chronological formulation that “time is brain.” We must recognize a more nuanced concept that the rate of tissue death as a function of time is not invariant, that still salvageable tissue at risk of infarction may be present up to 24 h after last-known well, and that those patients may strongly benefit from reperfusion. Multiple studies have sought to address this clinical dilemma using neuroimaging methods to identify a radiographic time-stamp of stroke onset or evidence of salvageable ischemic tissue and thereby increase the number of patients eligible for reperfusion therapies. In this review, we provide a critical analysis of the current state of neuroimaging techniques to select patients with unwitnessed stroke for revascularization therapies and speculate on the future direction of this clinically relevant area of stroke research.

Platelet count and indoor cold exposure among elderly people: A cross-sectional analysis of the HEIJO-KYO study

Background

Excess mortality from cardiovascular disease during cold seasons is a worldwide issue. Although some physiologic studies suggests that platelet activation via cold exposure may cause an increased incidence of cardiovascular disease in winter, the influence of indoor cold exposure in real-life situations on platelet (PLT) count remains unclear.

Methods

A cross-sectional study was conducted among 1095 elderly individuals. After obtaining a venous sample in the morning, indoor temperature of participants' home was measured every 10 min for 48 h. The mean indoor temperature while the participants stayed at home was calculated. All measurement was conducted during cold seasons (October to April) from 2010 to 2014.

Results

The mean age of the 1095 participants was 71.9 years. They spent 87.3% of the day at home (20 h 27 min). A 1 °C lower daytime indoor temperature was associated with a significant increase in PLT count of 1.47 × 10⁹/L (95% confidence interval, 0.39–2.56 × 10⁹/L). Compared with the warmest tertile group (20.1 [standard deviation {SD}, 0.09] °C), the coldest group (11.7 [SD, 0.12] °C) showed a 5.2% higher PLT count (238.84 [SD, 3.30] vs. 226.48 [SD, 3.32] × 10⁹/L; P = 0.01), even after adjusting for basic characteristics (age, gender, body weight, and smoking), antihypertensive medication, comorbidities (diabetes, estimated glomerular filtration rate), socioeconomic status (household income and education), day length, and outdoor temperature.

Conclusions

We found a significant and independent association between lower indoor temperature and higher PLT count among elderly in winter.

•

Lower daytime indoor temperature was associated with higher PLT count in winter.

•

The association was independent of outdoor temperature and socioeconomic status.

•

The 1095 elderly participants spent the majority of their time at home (87.3%).

Association Between Dehydration and Short-Term Risk of Ischemic Stroke in Patients with Atrial Fibrillation

Previous cross-sectional studies have demonstrated a higher incidence of dehydration in patients admitted for stroke suggesting a possible association. However, the temporality of the association has not been well established. We examined whether dehydration increases the risk of ischemic stroke in patients with a recent hospitalization for atrial fibrillation (AF). Data was from 1994 to 2012 from the Myocardial Infarction Data Acquisition System (MIDAS), a repository of in-patient records New Jersey hospitals, for AF hospitalizations (n = 1,282,787). Estimates for the association between AF hospitalization with/without dehydration and ischemic stroke within 30 days post-AF discharge were determined using log-linear multivariable modeling adjusting for socio-demographic factors and comorbid conditions. Within 10 days of discharge for AF, patients 18-80 years old (YO) with comorbid dehydration had a 60 % higher risk of ischemic stroke compared to AF patients without comorbid dehydration (adjusted risk ratio (ARR) 1.60, 95 % confidence interval (CI) 1.28-2.00). Eighteen- to 80-YO patients had a 34 % higher risk of ischemic stroke in days 11-20 post-AF discharge (ARR 1.34, 95 % CI 1.04, 1.74). There was no difference in the risk of stroke in 18-80-YO patients with or without prior dehydration during days 21-30 post-AF discharge. We also found no difference in the risk of ischemic stroke during any time period in patients over 80 YO. Dehydration may be a significant risk factor for ischemic stroke in patients 18-80 YO with AF.

What to do With Wake-Up Stroke

Wake-up stroke, defined as the situation where a patient awakens with stroke symptoms that were not present prior to falling asleep, represents roughly 1 in 5 acute ischemic strokes and remains a therapeutic dilemma. Patients with wake-up stroke were excluded from most ischemic stroke treatment trials and are often not eligible for acute reperfusion therapy in clinical practice, leading to poor outcomes. Studies of neuroimaging with standard noncontrast computed tomography (CT), magnetic resonance imaging (MRI), and multimodal perfusion-based CT and MRI suggest wake-up stroke may occur shortly before awakening and may assist in selecting patients for acute reperfusion therapies. Pilot studies of wake-up stroke treatment based on these neuroimaging features are promising but have limited generalizability. Ongoing randomized treatment trials using neuroimaging-based patient selection may identify a subset of patients with wake-up stroke that can safely benefit from acute reperfusion therapies.

Therapeutic applications of circadian rhythms for the cardiovascular system

The cardiovascular system exhibits dramatic time-of-day dependent rhythms, for example the diurnal variation of heart rate, blood pressure, and timing of onset of adverse cardiovascular events such as heart attack and sudden cardiac death. Over the past decade, the circadian clock mechanism has emerged as a crucial factor regulating these daily fluctuations. Most recently, these studies have led to a growing clinical appreciation that targeting circadian biology offers a novel therapeutic approach toward cardiovascular (and other) diseases. Here we describe leading-edge therapeutic applications of circadian biology including (1) timing of therapy to maximize efficacy in treating heart disease (chronotherapy); (2) novel biomarkers discovered by testing for genomic, proteomic, metabolomic, or other factors at different times of day and night (chronobiomarkers); and (3) novel pharmacologic compounds that target the circadian mechanism with potential clinical applications (new chronobiology drugs). Cardiovascular disease remains a leading cause of death worldwide and new approaches in the management and treatment of heart disease are clearly warranted and can benefit patients clinically.

Influence of Different β-Blockers on Platelet Aggregation in Patients With Coronary Artery Disease on Dual Antiplatelet Therapy

INTRODUCTION

The use of β-blockers in the treatment of patients with coronary heart disease is associated with a decrease in the frequency of angina pectoris and mortality of patients. Due to the severity of the disease and previous cardiovascular interventions, many patients with coronary artery disease (CAD) use dual antiplatelet therapy to achieve greater inhibition of platelet aggregation. The influence of β-blockers on platelet aggregation in patients using antiplatelet therapy is not well understood.

OBJECTIVE

To examine the effect of different β-blockers on platelet aggregation in patients on dual antiplatelet therapy.

METHODOLOGY

The study included 331 patients who were treated at the Department of Cardiology, Clinical Center Kragujevac during 2011. Patients were divided into 4 groups depending on the type of β-blockers that were used (bisoprolol, nebivolol, metoprolol, and carvedilol). Platelet aggregation was measured using the multiplate analyzer and expressed through the value of adenosine diphosphate (ADP) test (to assess the effect of clopidogrel), ASPI test (to assess the effect of acetyl salicylic acid), TRAP test (to assess baseline platelet aggregation), and the ratio of ADP/TRAP and ASPI/TRAP ASPI/TRAP (ASPI - aranchidonic acid induced aggregation, TRAP - thrombin receptor activating peptide) representing the degree of inhibition of platelet aggregation compared to the basal value. In consideration were taken the representation of demographic, clinical characteristics, laboratory parameters, and cardiovascular medications between the groups.

RESULTS

Patients who used nebivolol had a significantly lower value of the ratio of ADP/TRAP (0.39 ± 0.30) compared to patients who used bisoprolol (0.48 ± 0.26; P = .038), and trend toward the lower values of ADP test (328.0 ± 197.3 vs 403.7 ± 213.2; P = .059), while there was no statistically significant difference in values of other laboratory parameters of platelet function between other groups.

CONCLUSION

Patients with CAD on dual antiplatelet therapy who used nebivolol had significantly lower levels of residual ADP-induced platelet aggregation compared to baseline than patients who used bisoprolol.

Wake-up stroke and stroke of unknown onset: a critical review

Patients, who wake up with an ischemic stroke, account for a large number of the total stroke population, due to circadian morning predominance of stroke. Currently, this subset of patients is excluded from revascularization-therapy since no exact time of onset is known. A large group of these patients might be eligible for therapy. In this review, we assessed the current literature about the hypothesis that wake-up-strokes occur just prior on awakening and if this subgroup differs in characteristics compared to the overall stroke population. We looked at the safety and efficacy of thrombolysis and interventional techniques in the group of patients with unknown stroke-onset. We performed a meta-analysis of the diagnostic accuracy of the diffusion-FLAIR mismatch in identifying stroke within 3 and 4.5 h. The different imaging-selection criteria that can be used to treat these patients are discussed. Additional research on imaging findings associated with recent stroke and penumbral imaging will eventually lead to a shift from a rigid time-frame based therapy to a tissue-based individualized treatment approach.

Clinical management guidelines for subarachnoid haemorrhage. Diagnosis and treatment

OBJECTIVE

To update the Spanish Society of Neurology's guidelines for subarachnoid haemorrhage diagnosis and treatment.

MATERIAL AND METHODS

A review and analysis of the existing literature. Recommendations are given based on the level of evidence for each study reviewed.

RESULTS

The most common cause of spontaneous subarachnoid haemorrhage (SAH) is cerebral aneurysm rupture. Its estimated incidence in Spain is 9/100 000 inhabitants/year with a relative frequency of approximately 5% of all strokes. Hypertension and smoking are the main risk factors. Stroke patients require treatment in a specialised centre. Admission to a stroke unit should be considered for SAH patients whose initial clinical condition is good (Grades I or II on the Hunt and Hess scale). We recommend early exclusion of aneurysms from the circulation. The diagnostic study of choice for SAH is brain CT (computed tomography) without contrast. If the test is negative and SAH is still suspected, a lumbar puncture should then be performed. The diagnostic tests recommended in order to determine the source of the haemorrhage are MRI (magnetic resonance imaging) and angiography. Doppler ultrasonography studies are very useful for diagnosing and monitoring vasospasm. Nimodipine is recommended for preventing delayed cerebral ischaemia. Blood pressure treatment and neurovascular intervention may be considered in treating refractory vasospasm.

CONCLUSIONS

SAH is a severe and complex disease which must be managed in specialised centres by professionals with ample experience in relevant diagnostic and therapeutic processes.

The human endogenous circadian system causes greatest platelet activation during the biological morning independent of behaviors

Background

Platelets are involved in the thromboses that are central to myocardial infarctions and ischemic strokes. Such adverse cardiovascular events have day/night patterns with peaks in the morning (∼9AM), potentially related to endogenous circadian clock control of platelet activation. The objective was to test if the human endogenous circadian system influences (1) platelet function and (2) platelet response to standardized behavioral stressors. We also aimed to compare the magnitude of any effects on platelet function caused by the circadian system with that caused by varied standardized behavioral stressors, including mental arithmetic, passive postural tilt and mild cycling exercise.

Methodology/Principal Findings

We studied 12 healthy adults (6 female) who lived in individual laboratory suites in dim light for 240 h, with all behaviors scheduled on a 20-h recurring cycle to permit assessment of endogenous circadian function independent from environmental and behavioral effects including the sleep/wake cycle. Circadian phase was assessed from core body temperature. There were highly significant endogenous circadian rhythms in platelet surface activated glycoprotein (GP) IIb-IIIa, GPIb and P-selectin (6–17% peak-trough amplitudes; p≤0.01). These circadian peaks occurred at a circadian phase corresponding to 8–9AM. Platelet count, ATP release, aggregability, and plasma epinephrine also had significant circadian rhythms but with later peaks (corresponding to 3–8PM). The circadian effects on the platelet activation markers were always larger than that of any of the three behavioral stressors.

Conclusions/Significance

These data demonstrate robust effects of the endogenous circadian system on platelet activation in humans—independent of the sleep/wake cycle, other behavioral influences and the environment. The ∼9AM timing of the circadian peaks of the three platelet surface markers, including platelet surface activated GPIIb-IIIa, the final common pathway of platelet aggregation, suggests that endogenous circadian influences on platelet function could contribute to the morning peak in adverse cardiovascular events as seen in many epidemiological studies.

Sudden cardiac death: epidemiology, circadian variation, and triggers

Sudden cardiac death (SCD) remains a major health issue accounting for over 5% of annual mortality in the Western world. There are several causes of SCD, most commonly, coronary artery disease. Although identifying the prodrome of SCD has attracted considerable interest, a large proportion of patients die before any medical contact is established. SCD onset seems to follow a circadian pattern, most likely because of exposure to endogenous and exogenous triggers. The aim of the present report is to review the current knowledge of epidemiology, patterns of onset, and triggers of SCD and present directions for future research with a focus on coronary artery disease.

Diurnal variation in platelet inhibition by clopidogrel

Morning increase in the occurrence of myocardial infarction, stroke and sudden cardiac death is a well-recognized phenomenon, which is in line with a morning enhancement of platelet aggregation. We investigated whether platelet inhibition during clopidogrel and aspirin therapy varies during the day. Fifty-nine consecutive patients (45 men and 14 women) with first ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary interventions (pPCI) on dual antiplatelet therapy were prospectively enrolled into the study. Blood samples were collected 4 days after start of clopidogrel treatment at 6.00 a.m., 10.00 a.m., 2.00 p.m. and 7.00 p.m. Arachidonic acid and adenosine diphosphate (ADP)-induced platelet aggregation were assessed by impedance aggregometry. Platelet inhibition by clopidogrel was lowest in the midmorning: median ADP-induced platelet aggregation was 55%, 17% and 27% higher at 10.00 a.m. compared to 6.00 a.m., 2.00 p.m. and 7.00 p.m., respectively (p < 0.002). Nonresponsiveness to clopidogrel defined according to the device manufacturer was 2.4-fold more frequent in the midmorning than in the early morning. We observed a more pronounced midmorning increase in ADP-induced platelet aggregation in diabetic patients when compared to non-diabetics. In contrast, no diurnal variation in the antiplatelet effect of aspirin was observed. In conclusion, in patients presenting with STEMI undergoing pPCI, platelet inhibition by clopidogrel is less strong in the midmorning hours. This periodicity in platelet aggregation in patients on dual antiplatelet therapy should be taken into consideration when assessing platelet function in clinical studies.

The influence of bisoprolol dose on ADP-induced platelet aggregability in patients on dual antiplatelet therapy

PURPOSE

Dual antiplatelet therapy is recommended after acute coronary syndrome or after percutaneous coronary intervention with coronary stent implantation. Many of the patients on dual antiplatelet therapy receive β-blockers; some of them could have antiaggregatory effect. Bisoprolol is a highly selective adrenoceptor-blocker, which is often used in the settings of percutaneous coronary intervention or acute coronary syndrome in patients on dual antiplatelet therapy. Its antiaggregative effect has not been extensively studied. Therefore, the aim of this study is to investigate the effect of bisoprolol on ADP-induced platelet aggregation in patients on dual antiplatelet therapy.

METHODS

Platelet aggregability has been measured in 100 patients on dual antiplatelet therapy with multiplate analyzer using ADP test in blood samples anticoagulated with heparin. ADP test values have been expressed by arbitrary units/minute. In univariate and multivariate regression analyses, we have investigated the influence of bisoprolol and its dose and also different factors, such as risk factors, concomitant drugs and their dosage, laboratory findings, on ADP test values.

RESULTS

Univariate regression analysis showed significant correlation between the bisoprolol dose and the ADP test value (P=0.046, B=52.55, 95% confidence interval 0.87-104.23), which was also shown in the multivariate regression analysis (P=0.018; B=57.011; 95% confidence interval 10.455-103.567).

CONCLUSION

We have identified a positive correlation between bisoprolol dose and ADP-induced platelet aggregability in patients on dual antiplatelet therapy.

Cardiovascular disease, chronopharmacotherapy, and the molecular clock

Cardiovascular functions such as heart rate and blood pressure show 24h variation. The incidence of cardiovascular diseases including acute myocardial infarction and arrhythmia also exhibits diurnal variation. The center of this circadian clock is located in the suprachiasmatic nucleus in the hypothalamus. However, recent findings revealed that each organ, including cardiovascular tissues, has its own internal clock, which has been termed a peripheral clock. The functional roles played by peripheral clocks have been reported recently. Since the peripheral clock is considered to play considerable roles in the processes of cardiac tissues, the identification of genes specifically regulated by this clock will provide insights into its role in the pathogenesis of cardiovascular disorders. In addition, the discovery of small compounds that modulate the peripheral clock will help to establish chronotherapeutic approaches. Understanding the biological relevance of the peripheral clock will provide novel approaches to the prevention and treatment of cardiovascular diseases.

Molecular time: an often overlooked dimension to cardiovascular disease

Diurnal rhythms influence cardiovascular physiology such as heart rate and blood pressure and the incidence of adverse cardiac events such as heart attack and stroke. For example, shift workers and patients with sleep disturbances, such as obstructive sleep apnea, have an increased risk of heart attack, stroke, and sudden death. Diurnal variation is also evident at the molecular level, as gene expression in the heart and blood vessels is remarkably different in the day as compared to the night. Much of the evidence presented here indicates that growth and renewal (structural remodeling) are highly dependent on processes that occur during the subjective night. Myocardial metabolism is also dynamic with substrate preference also differing day from night. The risk/benefit ratio of some therapeutic strategies and the appearance of biomarkers also vary across the 24-hour diurnal cycle. Synchrony between external and internal diurnal rhythms and harmony among the molecular rhythms within the cell is essential for normal organ biology. Cell physiology is 4 dimensional; the substrate and enzymatic components of a given metabolic pathway must be present not only in the right compartmental space within the cell but also at the right time. As a corollary, we show disrupting this integral relationship has devastating effects on cardiovascular, renal and possibly other organ systems. Harmony between our biology and our environment is vital to good health.

Diurnal physiology: core principles with application to the pathogenesis, diagnosis, prevention, and treatment of myocardial hypertrophy and failure

The circadian system has been shown to be fundamentally important in human health and disease. Recently, there have been major advances in our understanding of daily rhythmicity, and its relevance to human physiology, and to the pathogenesis and treatment of cardiac hypertrophy and heart failure. Cardiovascular tissues, such as heart and blood vessels, show remarkable daily variation in gene expression, metabolism, growth, and remodeling. Moreover, synchrony of daily molecular and physiological rhythms is integral to healthy organ growth and renewal. Disruption of these rhythms adversely affects normal growth, also the remodeling mechanisms in disease, leading to gross abnormalities in heart and vessels. These observations provide new insights into the pathogenesis, diagnosis, treatment, and prevention of heart disease. In this review, we focus on the recent advances in circadian biology and cardiovascular function, with particular emphasis on how this applies to human myocardial hypertrophy and heart failure, and the implications and importance for translational medicine.

Carotid endarterectomy performed in the morning is associated with increased cerebral microembolization

OBJECTIVES

Platelet function exhibits circadian variation with highest levels of activity in the morning and plays a central role in arterial thrombotic events, including thrombotic stroke following carotid endarterectomy (CEA). Prior to the platelet-rich thrombus occluding the carotid artery, multiple embolic signals are detected in the middle cerebral artery using transcranial Doppler ultrasound. We hypothesized that patients undergoing CEA early in the day may be at an increased stroke risk and this would manifest as an increased postoperative embolic count.

METHODS

Data were collected prospectively on 235 patients undergoing primary CEA. Accurate start and finish times were recorded in addition to the number of postoperative emboli detected in the first three hours after CEA using transcranial Doppler (TCD) monitoring.

RESULTS

For operations finishing before midday, there was a 3.6-fold increase in the number of emboli detected relative to afternoon finishes (53.2 vs 14.8, P = .002) with similar results for starts before 10:30 AM (48.1 vs 14.7, P =.002). There was also a significant correlation between start time and emboli count (P = .02). Of the 55 patients with no postoperative emboli, only 19 had a morning start (relative risk 0.63, P = .011). Patients were 6.9 times more likely to require treatment with Dextran-40 to prevent progression onto a thrombotic stroke if their CEA finished before midday (P = .008).

CONCLUSION

There is a significantly increased rate of postoperative embolization for operations begun earlier in the day. Carotid endarterectomies performed in the afternoon may be at less risk of developing postoperative thrombotic stroke.

Chronobiology of hemostasis and inferences for the chronotherapy of coagulation disorders and thrombosis prevention

The hemostatic system in its multiple components displays an intricate organization in time which is characterized by circadian (approximately 24-hour), circaseptan (approximately 7-day), menstrual (approximately monthly), and circannual (approximately yearly) bioperiodicities. The interaction of the rhythms of the variables participating in hemostasis determine transient risk states of thromboembolic events, including myocardial infarction and stroke, and of hemorrhage and hemorrhagic events, each with a unique timing. The circadian staging of the rhythms in vascular, cellular, and coagulation factors that favors blood coagulation and thrombosis coincides with the daily minimum in fibrinolytic activity; as a result there is elevated risk in the morning of acute myocardial infarction and stroke. Similar hemostatic rhythms may determine the epidemiology of thromboembolic and hemorrhagic events during the week, month and year. This article focuses on the large-amplitude circadian rhythms operative in the hemostatic system. Their implication for preventive and curative pharmacotherapy of hemostatic disorders is presented, with discussion of related problems.

Normalization of platelet reactivity in clopidogrel-treated subjects

BACKGROUND

Aspirin (ASA) + clopidogrel are commonly used in acute coronary syndrome (ACS), but persistent antiplatelet effects may complicate surgery.

METHODS AND RESULTS

To study the possibility of normalizing platelet reactivity after ASA + clopidogrel treatment, 11 healthy subjects received a 325-mg ASA + clopidogrel loading dose (300 or 600 mg dependent on study arm), followed by 81 mg of ASA + 75 mg of clopidogrel daily for 2 days. Platelet reactivity was assessed by light transmittance aggregometry (LTA) [challenged by adenosine diphosphate (ADP), arachidonic acid (AA), collagen, and thrombin receptor activating peptide (TRAP)] and flow cytometry for platelet activation by GPIIb/IIIa receptor exposure pretreatment, 4 and 72 h postload. To normalize platelet reactivity, increasing amounts of pooled platelets from five untreated volunteers [volunteers (V)-platelet-rich plasma (PRP)] were added ex vivo to the subject's PRP (S-PRP). At both 4 and 72 h, 40% and 50% V-PRP were needed to overcome platelet disaggregation in the 300 or 600 mg arms, respectively, after ADP challenge; an additional 10% V-PRP fully normalized aggregation. Recovery of function was linear with each incremental increase of V-PRP. ADP-induced GPIIb/IIIa activation showed the same pattern as LTA (r = 0.74). Forty percent V-PRP was required to normalize platelet function to AA, collagen, and TRAP.

CONCLUSION

Our results suggest that the pre-operative transfusion of 10 platelet concentrate units (the equivalent of 40% V-PRP) after a 300-mg clopidogrel loading or 12.5 units (50% V-PRP) after a 600 mg loading may adequately reverse clopidogrel-induced platelet disaggregation to facilitate postoperative hemostasis. An additional 2.5 units fully normalized platelet function. The potential clinical implications of our observations could include shorter hospitalizations and reduced bleeding complications. But these observations should be fully explored in an in vivo clinical setting with clopidogrel-treated patients before and after surgery.

Differences in circadian variation of cerebral infarction, intracerebral haemorrhage and subarachnoid haemorrhage by situation at onset

BACKGROUND

The precise time of stroke onset during sleep is difficult to specify, but this has a considerable influence on circadian variations of stroke onset.

AIM

To investigate circadian variations in situations at stroke onset--that is, in the waking state or during sleep--and their differences among subtypes.

METHODS

12,957 cases of first-ever stroke onset diagnosed from the Iwate Stroke Registry between 1991 and 1996 by computed tomography or magnetic resonance imaging were analysed. Circadian variations were compared using onset number in 2-h periods with relative risk for the expected number of the average of 12 2-h intervals in the waking state or during sleep in cerebral infarction (CIF), intracerebral haemorrhage (ICH) and subarachnoid haemorrhage (SAH).

RESULTS

ICH and SAH showed bimodal circadian variations and CIF had a single peak in all situations at onset, whereas all three subtypes showed bimodal circadian variations of stroke onset in the waking state only. These variations were different in that CIF showed a bimodal pattern with a higher peak in the morning and a lower peak in the afternoon, whereas ICH and SAH had the same bimodal pattern with lower and higher peaks in the morning and afternoon, respectively.

CONCLUSIONS

Sleep or status in sleep tends to promote ischaemic stroke and suppress haemorrhagic stroke. Some triggers or factors that promote ischaemic stroke and prevent haemorrhagic stroke in the morning cause different variations in the waking state between ischaemic and haemorrhagic stroke.

The effect of time of day and exercise on platelet functions and platelet-neutrophil aggregates in healthy male subjects

Platelet activation state changes by exercise. The effect of exercise time on platelet activation state and formation of platelet-neutrophil aggregates are not known yet. In this study the effect of exercise and time of day were examined on platelet activity with platelet-neutrophil aggregates. Ten moderately active males aged 27+/- 1.63 (mean+/-S.D.) years completed sub-maximal (70% VO(2max)) exercise trials for 30 min. Blood pressure (BP) was recorded. Venous blood samples were obtained at rest, immediately post-exercise and after 30 min of recovery. Whole blood was analysed for haematocrit (Hct), haemoglobin (Hb), platelet count (PC), mean platelet count (MPV) and platelet aggregation (PA). Platelet-neutrophil aggregates and beta-thromboglobulin (beta-TG) levels were assayed. Platelet count showed significant increase after morning exercise ((236+/- 32)x10(9) l(-1) versus (202+/- 34)x10(9) l(-1) baseline, p < 0.05). Exercise resulted in significantly lower MPV after the evening exercise (9.16+/- 0.5 fl versus 9.65+/- 0.36 fl, p < 0.05). Platelet aggregation by adenosine diphosphate (ADP) decreased after morning exercise and the recovery aggregation levels were significantly different at two different times of the day (68+/- 20% a.m. versus 80+/- 12% p.m., p < 0.05). It was also showed that platelet-neutrophil aggregates increased significantly from baseline after both exercises. Exercise-induced platelet-neutrophil aggregates were higher in the evening (10.7+/- 1.3% p.m. versus 6.4+/- 1.8% a.m., p < 0.0001). It is therefore concluded that besides platelet-platelet aggregation, exercise can cause platelet- neutrophil aggregates. In addition, time of day has an effect on platelet activation related events. Circadian variations of physiological parameters may have an effect on thrombus formation by platelet activation.

Diurnal Variation of Soluble E- and P-Selectin, and Intercellular Adhesion Molecule-1 in Patients with and without Coronary Artery Disease

BACKGROUND

The more frequent onset of acute coronary syndromes (ACS) in the morning has been known for a long time. Diurnal changes of fibrinolysis such as lower activity of tissue plasminogen activator and higher activity of plasminogen activator inhibitor-1 (PAI-1) in the morning has been demonstrated previously and correspond with the manifestation of ACS. Less is known about the diurnal variation of soluble adhesion molecules as markers of endothelial or platelet activity in patients with coronary artery disease (CAD).

PATIENTS AND METHODS

80 patients with a history of myocardial infarction and/or chest pain with positive exercise testing admitted for elective coronary angiography were studied. 10 had normal findings on coronary angiography (control group), 70 patients had at least one or more stenoses >/=50% of the diameter of an epicardial vessel. None of the patients suffered from acute inflammation, connective or tumor disease. Blood samples were drawn at 7:00 a.m. and at 7:00 p.m. at rest and plasma concentration of soluble P-selectin (sP-selectin), E-selectin (sE-selectin), intercellular adhesion molecule-1 (sICAM-1) and acute-phase proteins were measured by ELISA.

RESULTS

In both groups, no diurnal variation was found in sE-selectin and sICAM-1. sP-selectin levels were significantly higher in the evening (CAD group: 149.8 +/- 54.5 vs. 172.2 +/- 68.8 ng/ml, p < 0.001; control: 148.7 +/- 75.5 vs. 187.5 +/- 96.3 ng/ml, p = 0.001, Wilcoxon test).

CONCLUSION

We have demonstrated diurnal variation of sP-selectin in patients with CAD. We conclude that high sP-selectin values in the evening represent the shed forms of the morning membrane-bound P-selectin.

Relationship between overnight neuroendocrine activity and morning haemostasis in working men

Sustained effects of SNS (sympathetic nervous system) and HPAA (hypothalamic–pituitary–adrenal axis) hyperactivity on haemostasis have not been investigated. In the present study, we tested for an association of overnight urinary catecholamine and cortisol excretion with morning plasma levels of fibrinogen, PAI-1 (plasminogen activator inhibitor-1) and D-dimer. Participants (639 male industrial employees) with a complete dataset were studied (age, 41±11 years; mean±S.D.). Subjects collected overnight urinary samples and had a fasting morning blood sample drawn. Measurement of urinary adrenaline (epinephrine), noradrenaline (norepinephrine) and cortisol were dichotomized to perform multivariate analyses of (co)variance. Haemostatic parameters were measured by ELISA. Fibrinogen was higher in men with high adrenaline (F7,631=5.68, P=0.018; where the subscripted value represents the degrees of freedom) and high noradrenaline (F7,631=4.19, P=0.041) compared with men with low excretion of the respective hormones. PAI-1 was higher in men with high cortisol than in men with low cortisol (F7,631=4.77, P=0.029). Interaction revealed that subjects with high cortisol/low noradrenaline had higher PAI-1 than subjects with low cortisol/high noradrenaline (P=0.038). Subjects with high adrenaline/high noradrenaline had higher D-dimer than subjects with high adrenaline/low noradrenaline (P=0.029), low adrenaline/high noradrenaline (P=0.022) and low adrenaline/low noradrenaline (not significant). When covariance for several confounders of haemostatic function was determined, the main effect of adrenaline on fibrinogen and the interaction between adrenaline and noradrenaline for D-dimer maintained significance. Although overnight SNS hyperactivity was associated independently with morning hypercoagulability, the relationship between the activity of HPAA and haemostasis was mediated by traditional cardiovascular risk factors.

Clinical Implication of Morning Blood Pressure Surge in Hypertension

Cardiovascular events occur most frequently in the morning. The morning surge in blood pressure may be associated with hypertensive target organ damage and subsequent cardiovascular risk in hypertensive patients. In our prospective study on elderly hypertensive patients, the morning blood pressure surge (defined as the increase from the lowest blood pressure during sleep to the average of the first 2 h after waking) was significantly associated with silent hypertensive cerebrovascular disease and subsequent stroke risk. This association was independent of age and 24-h ambulatory blood pressure levels. In addition, even after controlling for these factors and status of silent cerebrovascular disease, the contribution of the morning blood pressure surge remained significant, and a 10 mmHg increase in systolic morning blood pressure surge increase the stroke risk by 22%. A related factor is orthostatic hypertension, which might be associated with increased sympathetic activity, and which is significantly associated with an increase in morning blood pressure surge and ambulatory blood pressure variability. A possible implication is that, in addition to strict blood pressure control, antihypertensive medication that targets exaggerated morning blood pressure may achieve more effective prevention of cardiovascular events in hypertensive patients.