Exercise transiently increases the density of incipient blood clots in antiplatelet-treated lacunar stroke patients

INTRODUCTION

Older individuals and, in particular, individuals at risk of recurrent stroke, may be susceptible to thrombosis when participating in exercise, however, this aspect has not been well investigated.

METHODS

Clot microstructure and conventional markers of thrombotic risk were determined in twenty lacunar stroke patients and fifteen healthy age-matched controls before, immediately after and 1 h after a bout of moderate intensity cycling exercise. Data were analyzed using a linear mixed model approach.

RESULTS

At rest, clot microstructure (1.69 ± 0.07 vs. 1.64 ± 0.05, corresponding to a difference of ~ 50% in normalized clot mass; p = 0.009) and thrombocyte count (73%; p < 0.0001) were higher, and activated partial thromboplastin time was lower (18%; p = 0.0001) in stroke patients compared to age-matched controls. Acute exercise increased thrombogenic markers similarly in the two groups: incipient clot microstructure (1.69 ± 0.07 vs. 1.74 ± 0.05; p = 0.0004 and 1.64 ± 0.05 vs. 1.71 ± 0.04; p < 0.0001, for stroke and controls respectively), plasma fibrinogen (12%; p < 0.0001 and 18%; p < 0.0001, for stroke and controls respectively) and the combined coagulation factors II, VII and X (p = 0.0001 and p < 0.0001, for stroke and controls respectively).

CONCLUSION

The results show that exercise transiently increases the risk of blood clot formation in both stroke patients and controls, however, due to the higher baseline thrombogenicity in stroke patients, the post exercise risk of forming blood clots may be higher in this group.

TRIAL REGISTRATION

Registered at ClinicalTrials.gov (NCT03635177).

Prediction of underlying atrial fibrillation in patients with a cryptogenic stroke: results from the NOR-FIB Study

BACKGROUND

Atrial fibrillation (AF) detection and treatment are key elements to reduce recurrence risk in cryptogenic stroke (CS) with underlying arrhythmia. The purpose of the present study was to assess the predictors of AF in CS and the utility of existing AF-predicting scores in The Nordic Atrial Fibrillation and Stroke (NOR-FIB) Study.

METHOD

The NOR-FIB study was an international prospective observational multicenter study designed to detect and quantify AF in CS and cryptogenic transient ischaemic attack (TIA) patients monitored by the insertable cardiac monitor (ICM), and to identify AF-predicting biomarkers. The utility of the following AF-predicting scores was tested: AS5F, Brown ESUS-AF, CHA₂DS₂-VASc, CHASE-LESS, HATCH, HAVOC, STAF and SURF.

RESULTS

In univariate analyses increasing age, hypertension, left ventricle hypertrophy, dyslipidaemia, antiarrhythmic drugs usage, valvular heart disease, and neuroimaging findings of stroke due to intracranial vessel occlusions and previous ischemic lesions were associated with a higher likelihood of detected AF. In multivariate analysis, age was the only independent predictor of AF. All the AF-predicting scores showed significantly higher score levels for AF than non-AF patients. The STAF and the SURF scores provided the highest sensitivity and negative predictive values, while the AS5F and SURF reached an area under the receiver operating curve (AUC) > 0.7.

CONCLUSION

Clinical risk scores may guide a personalized evaluation approach in CS patients. Increasing awareness of the usage of available AF-predicting scores may optimize the arrhythmia detection pathway in stroke units.

Underlying causes of cryptogenic stroke and TIA in the nordic atrial fibrillation and stroke (NOR-FIB) study - the importance of comprehensive clinical evaluation

BACKGROUND

Cryptogenic stroke is a heterogeneous condition, with a wide spectrum of possible underlying causes for which the optimal secondary prevention may differ substantially. Attempting a correct etiological diagnosis to reduce the stroke recurrence should be the fundamental goal of modern stroke management.

METHODS

Prospective observational international multicenter study of cryptogenic stroke and cryptogenic transient ischemic attack (TIA) patients clinically monitored for 12 months to assign the underlying etiology. For atrial fibrillation (AF) detection continuous cardiac rhythm monitoring with insertable cardiac monitor (Reveal LINQ, Medtronic) was performed. The 12-month follow-up data for 250 of 259 initially included NOR-FIB patients were available for analysis.

RESULTS

After 12 months follow-up probable stroke causes were revealed in 43% patients, while 57% still remained cryptogenic. AF and atrial flutter was most prevalent (29%). In 14% patients other possible causes were revealed (small vessel disease, large-artery atherosclerosis, hypercoagulable states, other cardioembolism). Patients remaining cryptogenic were younger (p < 0.001), had lower CHA₂DS₂-VASc score (p < 0.001) on admission, and lower NIHSS score (p = 0.031) and mRS (p = 0.016) at discharge. Smoking was more prevalent in patients that were still cryptogenic (p = 0.014), while dyslipidaemia was less prevalent (p = 0.044). Stroke recurrence rate was higher in the cryptogenic group compared to the group where the etiology was revealed, 7.7% vs. 2.8%, (p = 0.091).

CONCLUSION

Cryptogenic stroke often indicates the inability to identify the cause in the acute phase and should be considered as a working diagnosis until efforts of diagnostic work up succeed in identifying a specific underlying etiology. Timeframe of 6-12-month follow-up may be considered as optimal.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02937077, EudraCT 2018-002298-23.

Atrial fibrillation in cryptogenic stroke and TIA patients in the nordic atrial fibrillation and stroke The Nordic Atrial Fibrillation and Stroke (NOR-FIB) Study: Main results

Introduction:

Secondary stroke prevention depends on proper identification of the underlying etiology and initiation of optimal treatment after the index event. The aim of the NOR-FIB study was to detect and quantify underlying atrial fibrillation (AF) in patients with cryptogenic stroke (CS) or transient ischaemic attack (TIA) using insertable cardiac monitor (ICM), to optimise secondary prevention, and to test the feasibility of ICM usage for stroke physicians.

Patients and methods:

Prospective observational international multicenter real-life study of CS and TIA patients monitored for 12 months with ICM (Reveal LINQ) for AF detection.

Results:

ICM insertion was performed in 91.5% by stroke physicians, within median 9 days after index event. Paroxysmal AF was diagnosed in 74 out of 259 patients (28.6%), detected early after ICM insertion (mean 48 ± 52 days) in 86.5% of patients. AF patients were older (72.6 vs 62.2; p < 0.001), had higher pre-stroke CHA₂DS₂-VASc score (median 3 vs 2; p < 0.001) and admission NIHSS (median 2 vs 1; p = 0.001); and more often hypertension ( p = 0.045) and dyslipidaemia ( p = 0.005) than non-AF patients. The arrhythmia was recurrent in 91.9% and asymptomatic in 93.2%. At 12-month follow-up anticoagulants usage was 97.3%.

Discussion and conclusions:

ICM was an effective tool for diagnosing underlying AF, capturing AF in 29% of the CS and TIA patients. AF was asymptomatic in most cases and would mainly have gone undiagnosed without ICM. The insertion and use of ICM was feasible for stroke physicians in stroke units.

Prognosis and antithrombotic practice patterns in recurrent and transient atrial fibrillation following acute coronary syndrome: a nationwide study

Background

First-time detected atrial fibrillation (AF) during acute coronary syndrome (ACS) aggravates the prognosis and increases the risk of ischemic stroke. In this setting, AF may present as brief and transient or with recurrent episodes after discharge. However, data on the association between transient or recurrent AF and ischemic stroke in patients with ACS are sparse. Further, despite being associated with ischemic stroke, first-time detected AF patients have been reported with low oral anticoagulation (OAC) rates.

Purpose

To examine the associated rate of ischemic stroke and mortality in ACS survivors with transient or recurrent AF and to assess the antithrombotic practice patterns one year after ACS.

Methods

Using data from Danish nationwide registries, we identified all patients with first-time ACS, without known AF prior to ACS, from 2000–2017 who were alive one year after ACS discharge (index date). According to a grace period between ACS discharge and one year after ACS discharge, patients were categorized into: i) no AF; ii) first-time detected AF during ACS admission without AF recurrence (transient AF); and iii) first-time detected AF during ACS admission with a subsequent recurrent AF episode (recurrent AF). Patients who developed AF during the grace period were excluded. Patients were followed from one year post ACS discharge, and two-year rates of ischemic stroke and mortality were compared using multivariable adjusted Cox proportional hazards analysis. Further, we assessed the prescribed OAC rates in a three-month period following the index date.

Results

We included 116,793 patients surviving one year post ACS discharge: 111,708 (95.6%) without AF (64.9% male, median age 64 years), 2,671 (2.3%) with transient AF (58.0% male, median age 74 years), and 2,414 (2.1%) with recurrent AF (55.2% male, median age 76 years). The cumulative two-year incidence of ischemic stroke was 0.9%, 1.5%, and 2.3% for patients without AF, transient AF, and recurrent AF, respectively (Figure 1). The cumulative two-year incidence of mortality was 7.4%, 12.1%, and 20.3% for patients without AF, transient AF, and recurrent AF, respectively (Figure 1). Compared to those without AF, the adjusted two-year rates of outcomes were as follows: ischemic stroke: HR 1.15 (95% CI: 0.81–1.61) for patients with transient AF and HR 1.50 (95% CI: 1.14–1.98) for patients with recurrent AF; mortality: HR 0.98 (95% CI: 0.87–1.10) for patients with transient AF and HR 1.35 (95% CI: 1.23–1.49) for patients with recurrent AF (Figure). We identified that 20.9% for transient AF and 42.2% for recurrent AF were prescribed OAC therapy in the three-month period after one year.

Conclusion

In patients surviving one year after ACS with first-time detected AF, a recurrent AF episode was associated with an increased long-term rate of ischemic stroke and mortality, while transient AF yielded no statistically difference as compared with patients without AF.

Funding Acknowledgement

Type of funding sources: None.

Increasing time to thrombolysis is associated with worse long-term outcomes in patients with ischaemic stroke: a nationwide study

Background

It is well-established that the short-term benefits of intravenous thrombolytic therapy are reduced with increasing treatment delay in patients with acute ischaemic stroke. However, there is a paucity of contemporary data on the association between time from symptom onset to initiation of thrombolysis and long-term outcomes. With improving post-stroke survival in the Western world, data on time to thrombolysis and subsequent long-term outcomes are warranted in order to provide further insight into the importance of time to treatment.

Purpose

To examine the long-term risk of adverse outcomes according to time from symptom onset to intravenous thrombolytic therapy in patients with acute ischaemic stroke.

Methods

In this observational cohort study, we identified all patients with first-time ischaemic stroke treated with intravenous thrombolysis between 2011–2015 and alive at discharge through the Danish National Stroke Registry. Patients who received thrombolysis after &gt;270 min were excluded. Using multivariable Cox regression, we examined associations between time from symptom onset to thrombolysis and risks of the composite of death, recurrent ischaemic stroke, and dementia, as well as each of these components separately. Patients were followed until the outcome of interest, emigration, or December 31, 2017.

Results

Of the 4,313 patients with first-time ischaemic stroke treated with intravenous thrombolysis, 4,119 were alive at discharge (median age 69 years [25th-75th percentile 59–78 years], 60% males). The median follow-up was 3.3 years (25th-75th percentile 2.3–4.7 years). The median time from symptom onset to initiation of thrombolytic therapy was 140 min (25th-75th percentile 106–187 min), and the median National Institutes of Health Stroke Scale score at presentation was 5 (25th-75th percentile 3–10). The unadjusted absolute 3-year risks of the composite outcome, death, recurrent ischaemic stroke, and dementia according to time to thrombolysis are displayed in the figure. Compared with thrombolysis within 90 min, time to thrombolysis &gt;90 min was associated with a higher relative risk of the composite outcome (91–180 min: adjusted hazard ratio [HR] 1.37 [95% confidence interval [CI], 1.13–1.68]; 181–270 min: adjusted HR 1.42 [95% CI 1.15–1.76]). The risks of each component of the composite outcome according to time to thrombolysis were similar to results for the composite endpoint, as illustrated in the figure.

Conclusions

In this nationwide cohort of patients with acute ischaemic stroke treated with thrombolysis, increasing time from symptom onset to initiation of intravenous thrombolytic therapy was associated with higher long-term risks of the composite of death, recurrent ischaemic stroke, and dementia, as well as all three outcomes separately. These data indicate that long-term outcomes of patients with ischaemic stroke treated with intravenous thrombolysis can be greatly improved by reducing treatment delay.

Time to thrombolysis and outcomes

Funding Acknowledgement

Type of funding source: None

Declining incidence and mortality of ischaemic stroke between 1996–2016: a nationwide study

Background

The incidence and mortality of ischaemic heart disease have been declining over many years. The development with ischaemic stroke is less well studied, and with an increasing elderly population, there is a need for large-scale studies. Recent changes in stroke prevention and treatments may have affected the incidence and mortality of ischaemic stroke.

Purpose

To examine time trends and sex and age differences in the incidence and mortality of first-time ischaemic stroke in Denmark between 1996–2016.

Methods

In this observational cohort study, we used Danish nationwide registries to identify all individuals &gt;18 years of age admitted with a first-time diagnosis of ischaemic stroke between 1996–2016. We calculated age- and sex-stratified annual incidence rates and absolute 30-day and 1-year mortality risks. Further, we calculated annual incidence rate ratios using multivariable Poisson regression, odds ratios for 30-day mortality using multivariable logistic regression, and hazard ratios for 1-year mortality using multivariable Cox regression.

Results

The study population consisted of 224,617 individuals &gt;18 years of age with first-time ischaemic stroke between 1996–2016. The figure displays the unadjusted incidence rates and 1-year mortality risks of ischaemic stroke by calendar year. The overall unadjusted incidence rates of ischaemic stroke per 1,000 person-years increased from 1996 (2.43 [95% confidence interval [CI], 2.38–2.47]) to 2002 (2.91 [95% CI, 2.86–2.96]) and then gradually decreased to below the initial level until 2016 (1.99 [95% CI, 1.95–2.03]). Men had higher incidence rates than women in all age groups except in patients between 18–30 years and &gt;85 years. The absolute mortality risk decreased between 1996–2016 (30-day mortality from 17.1% to 7.6% and 1-year mortality from 30.9% to 17.3%). Women had higher mortality than men in the age groups 55–64 years and &gt;85 years. Similar trends were observed for all analyses after multivariable adjustment.

Conclusions

The overall incidence of first-time hospitalization for ischaemic stroke increased from 1996–2002 and then gradually decreased to below the initial level until 2016. The absolute 30-day and 1-year mortality risk decreased between 1996–2016. These findings correspond to the increased awareness of stroke prevention and introduction of new treatment options during the study period.

Trends in stroke incidence and mortality

Funding Acknowledgement

Type of funding source: None

miRNA-27a-3p and miRNA-222-3p as Novel Modulators of Phosphodiesterase 3a (PDE3A) in Cerebral Microvascular Endothelial Cells

Endothelial dysfunction is a key element in cerebral small vessel disease (CSVD), which may cause stroke and cognitive decline. Cyclic nucleotide signaling modulates endothelial function. The cyclic adenosine monophosphate-degrading enzyme phosphodiesterase 3 (PDE3) is an important treatment target which may be modulated by microRNAs (miRNAs) important for regulating gene expression. We aimed to identify PDE3-targeting miRNAs to highlight potential therapeutic targets for endothelial dysfunction and CSVD. PDE3-targeting miRNAs were identified by in silico analysis (TargetScan, miRWalk, miRanda, and RNA22). The identified miRNAs were ranked on the basis of TargetScan context scores and their expression (log2 read counts) in a human brain endothelial cell line (hCMEC/D3) described recently. miRNAs were subjected to co-expression meta-analysis (CoMeTa) to create miRNA clusters. The pathways targeted by the miRNAs were assigned functional annotations via the KEGG pathway and COOL. hCMEC/D3 cells were transfected with miRNA mimics miR-27a-3p and miR-222-3p, and the effect on PDE3A protein expression was analyzed by Western blotting. Only PDE3A is expressed in hCMEC/D3 cells. The in silico prediction identified 67 PDE3A-related miRNAs, of which 49 were expressed in hCMEC/D3 cells. Further analysis of the top two miRNA clusters (miR-221/miR-222 and miR-27a/miR-27b/miR-128) indicated a potential link to pathways relevant to cerebral and vascular integrity and repair. hCMEC/D3 cells transfected with miR-27a-3p and miR-222-3p mimics had reduced relative expression of PDE3A protein. PDE3A-related miRNAs miR-221/miR-222 and miR-27a/miR-27b/miR-128 are potentially linked to pathways essential for immune regulation as well as cerebral and vascular integrity/function. Furthermore, relative PDE3A protein expression was reduced by miR27a-3p and miR-222-3p.

Choroid plexus aquaporin 1 and intracranial pressure are increased in obese rats: towards an idiopathic intracranial hypertension model?

BACKGROUND/OBJECTIVES

Idiopathic intracranial hypertension (IIH) is a condition of increased intracranial pressure (ICP) without identifiable cause. The majority of IIH patients are obese, which suggests a connection between ICP and obesity. The aim of the study was to compare ICP in lean and obese rats. We also aimed to clarify if any ICP difference could be attributed to changes in some well-known ICP modulators; retinol and arterial partial pressure of CO₂ (pCO₂). Another potential explanation could be differences in water transport across the choroid plexus (CP) epithelia, and thus we furthermore investigated expression profiles of aquaporin 1 (AQP1) and Na/K ATPase.

METHODS

ICP was measured in obese and lean Zucker rats over a period of 28 days. Arterial pCO₂ and serum retinol were measured in serum samples. The CPs were isolated, and target messenger RNA (mRNA) and protein were analyzed by quantitative PCR and western blot, respectively.

RESULTS

Obese rats had elevated ICP compared to lean controls on all recording days except day 0 (P<0.001). Serum retinol (P=0.35) and arterial pCO₂ (P=0.16) did not differ between the two groups. Both AQP1 mRNA and protein levels were increased in the CP of the obese rats compared to lean rats (P=0.0422 and P=0.0281). There was no difference in Na/K ATPase mRNA or protein levels (P=0.2688 and P=0.1304).

CONCLUSION

Obese Zucker rats display intracranial hypertension and increased AQP1 expression in CP compared to lean controls. The mechanisms behind these changes are still unknown, but appear to be unrelated to altered pCO₂ levels or retinol metabolism. This indicates that the increase in ICP might be related to increased AQP1 levels in CP. Although further studies are warranted, obese Zucker rats could potentially model some aspects of the IIH pathophysiology.

The CGRP-Antagonist, BIBN4096BS Does not Affect Cerebral or Systemic Haemodynamics in Healthy Volunteers

BIBN4096BS is a CGRP-antagonist effective in the treatment of migraine. Blocking the receptor of a strong vasodilator involves a theoretical risk of causing cerebral vasoconstriction, a probability not previously investigated with BIBN4096BS. Seven healthy volunteers completed this double-blinded placebo-controlled crossover study. The volunteers received randomly 10 min infusions of either placebo, 2.5 mg or 10 mg of BIBN4096BS on 3 separate days. Transcranial Doppler was used to measure the middle cerebral artery blood flow velocity (VMCA); global and regional cerebral blood flow (rCBFMCA) was measured by 133-Xenon inhalation SPECT. The diameter of the temporal and radial artery was measured by highresolution ultrasound. Systemic haemodynamics and partial pressure of CO2 (PetCO2), and adverse events were monitored regularly. BIBN4096BS had no influence on global or regional cerebral blood flow, or on the blood flow velocity in the middle cerebral artery. There was no effect on systemic haemodynamics and adverse events were minor. We conclude that there is no effect of CGRP-receptor blockade on the cerebral or systemic circulation in humans. Circulating CGRP is therefore not likely to exert a vasodilatory activity in the resting state and the use of BIBN4096BS for acute migraine seems to be without risk of cerebral vasoactivity. These data suggest that BIBN4096BS is the first specific antimigraine drug without vasoactive effect.

A nitric oxide donor (nitroglycerin) triggers genuine migraine attacks

Supersensitivity to induction of headache and arterial dilatation by a donor of nitric oxide (nitroglycerin) has recently been demonstrated in migraine sufferers. The aims of the present study were to examine whether the nitric oxide donor nitroglycerin may induce a typical migraine attack, to exclude placebo-related effects and to describe the relation between middle cerebral artery dilatation and provoked migraine. Nitroglycerin (0.5 μg/kg/min for 20 min) or placebo was infused into 12 migraine patients in a double-blind cross-over trial. Blood velocity in the middle cerebral artery was measured with transcranial Doppler and characteristics of headache and accompanying symptoms were recorded frequently. Headache occurred during the nitroglycerin infusion as previously described but peak headache intensity did first occur 5.5 h after infusion. At this time the induced headaches in 8 of 10 completing patients fulfilled the diagnostic criteria for migraine without aura of the International Headache Society. Furthermore, all patients who normally had unilateral spontaneous migraine attacks also had unilateral headaches after nitroglycerin. Only one subject developed migraine after placebo (p < 0.03). The time pattern of headache and estimated middle cerebral artery dilatation corresponded well. The study therefore demonstrates that activation of the nitric oxide cGMP pathway may cause typical migraine attacks.

Calcitonin gene-related peptide (CGRP) levels during glyceryl trinitrate (GTN)-induced headache in healthy volunteers

The role of nitric oxide (NO) in migraine has been studied in the experimental glyceryl trinitrate (GTN)-infusion headache model. We hypothesized that GTN-induced headache may activate the trigeminovascular system and be associated with increased levels of sensory neuropeptides, including calcitonin gene-related peptide (CGRP). CGRP, vasoactive intestinal peptide (VIP), neuropeptide Y (NPY) and somatostatin plasma levels were measured before and after placebo/sumatriptan injection and during GTN-induced headache. Following a double-blind randomized cross-over design, 10 healthy volunteers received subcutaneous sumatriptan 6 mg or placebo. This was succeeded by 20 min of GTN (0.12 µg kg−1 min−1) infusion. At baseline no subject reported headache (using verbal rating scale from 0 to 10) and the jugular CGRP-like immunoreactivity (-LI) level was 18.6 ± 2.5 pmol/l. After a 20-min intravenous infusion of GTN 0.12 µg kg−1 min−1, median peak headache intensity was 4 (range 2–6) ( P < 0.05), while jugular CGRP-LI levels were unchanged (19.0 ± 2.8 pmol/l; P > 0.05). There were no changes in VIP-, NPY- or somatostatin-LI. In conclusion, the NO donor GTN appears not to induce headache via immediate CGRP release.

The headache-inducing effect of cilostazol in human volunteers

We have previously shown that nitric oxide (NO) and cyclic guanosine monophosphate (GMP) may cause headache and migraine. However, not all findings in previous studies can be explained by an activation of the NO-cGMP pathway. Calcitonin gene-related peptide (CGRP) causes headache and migraine in migraine patients, but CGRP receptor activation causes an increase in cyclic adenosine monophosphate (cAMP). In order to investigate the role of cAMP in vascular headache pathogenesis, we studied the effect of cilostazol, an inhibitor of cAMP degradation, in our human experimental headache model. Twelve healthy volunteers were included in a double-blind, randomized, crossover study. Placebo or cilostazol (200 mg p.o.) was administered on two separate study days. Headache was scored on a verbal rating scale (0-10) and mechanical pain thresholds were measured with von Frey hairs. The median peak headache score 0-16 h postdose was 0 (range 0-2) after placebo and 3.5 (range 0-7) after cilostazol (P = 0.003). The median headache curve peaked at 6-9 h postdose. The headaches induced were usually bilateral and pulsating. Nausea occurred in two volunteers, photo- and phonophobia were not seen. Two volunteers had a headache that fulfilled International Headache Society criteria for migraine without aura after cilostazol. No change in mechanical pain thresholds in the forehead was seen (P = 0.25). The headache after cilostazol was equal to or more severe than headache induced by glyceryl trinitrate in previous experiments. The present study thus indicates that increased levels of cAMP may play a role in headache and migraine pathogenesis.

Dipyridamole may induce migraine in patients with migraine without aura

Dipyridamole inhibits phosphodiesterase 5 (PDE5) and adenosine re-uptake. The most prominent side-effect is headache. We examined the migraine-generating effects of dipyridamole as well as the cerebral blood velocity response in a single-blind study, including 10 patients with migraine without aura and 10 healthy subjects. Dipyridamole 0.142 mg/kg per min was administered intravenously. Headache intensity was scored on a verbal rating scale along with pain characteristics and accompanying symptoms. Blood velocity in the middle cerebral artery (V(mca)), blood pressure and heart rate were recorded repeatedly. Headache was induced in all migraine patients and in eight of 10 healthy subjects (P = 0.47) with no significant difference in headache intensity (P = 0.53). However, five patients but only one healthy subject experienced the symptoms of migraine without aura, according to ICHD-2 criteria, within 12 h (P = 0.14). Four patients reported photophobia after dipyridamole compared with no healthy subjects (P = 0.087). V(mca) decreased (P < 0.001) during and after dipyridamole infusion with no difference between groups (P = 0.15) coinciding with initiation, but not cessation of immediate headache. Thus, dipyridamole induces symptoms of migraine and an initial decrease in V(mca) in migraine patients, but not significantly more than in healthy subjects. This relatively low frequency of migraine induction, compared with nitric oxide donors and sildenafil, is probably due to the less specific action of dipyridamole on the cGMP signalling pathway as well as a possible bidirectional effect of adenosine on migraine induction.

The effect of circulating adenosine on cerebral haemodynamics and headache generation in healthy subjects

Adenosine is an endogenous neurotransmitter that is released from the brain during hypoxia and relaxes isolated human cerebral arteries. Many cerebral artery dilators cause migraine attacks. However, the effect of intravenous adenosine on headache and cerebral artery diameter has not previously been investigated in man and reports regarding the effect of intravenous adenosine on cerebral blood flow are conflicting. Twelve healthy participants received adenosine 80, 120 microg kg(-1) min(-1) and placebo intravenously for 20 min, in a double-blind, three-way, crossover, randomized design. Headache was rated on a verbal scale (0-10). Regional cerebral blood flow (rCBF) with 133Xe inhalation and single-photon emission computed tomography (SPECT) and MCA flow velocity (V(MCA)) with transcranial Doppler, were measured in direct sequence. Six participants developed headache during 80 microg kg(-1) min(-1) and six during 120 microg kg(-1) min(-1) compared with none on placebo (P = 0.006). The headache was very mild and predominantly described as a pressing sensation. When correcting data for adenosine-induced hyperventilation, no significant changes in rCBF (P = 0.22) or V(MCA) (P = 0.16) were found between treatments. A significant dilation of the superficial temporal artery (STA) was seen (P < 0.001). These results show that circulating adenosine has no effect on rCBF or V(MCA), while it dilates the STA and causes very mild headache.

Plasma levels of cAMP, cGMP and CGRP in sildenafil-induced headache

Sildenafil, a selective inhibitor of the cyclic guanosine monophosphate (cGMP) degrading phosphodiestrase 5 (PDE5), induced migraine without aura in 10 of 12 migraine patients and in healthy subjects it induced significantly more headache than placebo. The aim of the present study was to determine whether the pain-inducing effects of sildenafil would be reflected in plasma levels of important signalling molecules in migraine: cGMP, cyclic adenosine monophosphate (cAMP) and calcitonin gene-related peptide (CGRP). Ten healthy subjects (four women, six men) and 12 patients (12 women) suffering from migraine without aura were included in two separate double-blind, placebo-controlled, cross-over studies in which placebo or sildenafil 100 mg was administered orally. Plasma levels of CGRP, cAMP and cGMP were determined in blood from the antecubital vein. Despite the ability of sildenafil to induce headache and migraine, no significant differences in plasma levels of CGRP, cGMP and cAMP were detected after sildenafil compared with placebo. In conclusion, plasma levels of CGRP, cGMP and cAMP remain normal during sildenafil-induced headache or migraine. However, since previous studies indicate an important role of these signalling molecules, the present study questions whether cAMP and cGMP in peripheral blood can be used for monitoring pathophysiological events in headache and migraine mechanisms.

The role of cGMP hydrolysing phosphodiesterases 1 and 5 in cerebral artery dilatation

The aim was to investigate the presence and activity of cGMP hydrolysing phosphodiesterases in guinea pig basilar arteries and the effect of selective and non-selective phosphodiesterase inhibitors on cerebral artery dilatation involving the nitric oxide (NO)-guanosine cyclic 3'5-monophosphate (cGMP) pathway. Immunoreactivity to phosphodiesterases 1A, 1B and 5, but not phosphodiesterase 1C was found in fractions of homogenised cerebral arteries eluted by high-pressure liquid chromatography (HPLC). Both the phosphodiesterase 1 inhibitor 8-methoxymethyl-1-methyl-3-(2methylpropyl)-xanthine (8-MM-IBMX) and the phosphodiesterase 5 inhibitors zaprinast and dipyridamole induced dilatation of cerebral arteries. The dilatory response to 8-MM-IBMX was reduced by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10 microM) and endothelial removal and restored by sodium nitroprusside (0.1 microM) pretreatment, indicating a close relation to the nitric oxide-cGMP pathway. The responses to zaprinast and dipyridamole, however, were not only moderately affected, but also restored by sodium nitroprusside (0.1 microM) pretreatment. At high concentrations, the dilatory effects of zaprinast and dipyridamole were partly caused by cGMP-independent mechanisms. Targeting the phosphodiesterases present in cerebral arteries, with selective inhibitors or activators of phosphodiesterase, may be a possible new way of treating cerebrovascular disease.

Effects of the non-selective phosphodiesterase inhibitor pentoxifylline on regional cerebral blood flow and large arteries in healthy subjects

The vasodilating properties of the non-selective phosphodiesterase (PDE) inhibitor pentoxifylline were evaluated. Pentoxifylline has been reported to increase cerebral blood flow (CBF) and improve recovery rate of stroke patients. Whether these results are due to a dilating effect on arteries or to other mechanisms is not clear. In the present double-blind crossover study, 10 healthy subjects received pentoxifylline 300 mg or placebo intravenously on separate days. Blood flow velocity in the middle cerebral artery (V(mca)) was recorded by transcranial Doppler and rCBF was measured using (133)Xenon-inhalation SPECT. High-frequency ultrasound was used for measurements of temporal and radial artery diameter. Cyclic guanosine monophosphate (cGMP) and cyclic adenosine monophosphate (cAMP) concentrations were assessed in plasma. Except for increased heart rate (P < 0.05), systolic blood pressure (P < 0.05) and plasma cAMP (P < 0.001), no significant differences in CBF, rCBF(mca) or plasma cGMP were seen between placebo and pentoxifylline infusion. During pentoxifylline infusion, V(mca) decreased 7.2% (SD 12.0; P < 0.05) and temporal artery diameter increased 9.0% (SD 7.0; P < 0.001), suggesting minor dilatation of the large arteries. However, this change was not significantly different from placebo. In conclusion, pentoxifylline 300 mg had no effect on rCBF. A possible minor dilatation of the middle cerebral artery and the temporal artery cannot be excluded. Any potential clinical effect of pentoxifylline is most likely mediated through non-vascular mechanisms.

Quality of life study in a regional group of patients with Crohn disease. A structured interview study

BACKGROUND

The course and prognosis of Crohn disease has previously been described in a regional group of patients in Copenhagen County. The aim of the present study was to reveal the quality of life. as judged by the patients, and compared to age- and sex-matched healthy controls.

METHODS

Out of 100 consecutive out-patients with Crohn disease, 94 patients accepted to participate together with 94 age- and sex-matched healthy controls. A modified McMaster Inflammatory Bowel Disease Questionnaire (IBDQ23) was used, excluding bowel-related questions. Medical students conducted interviews without knowing who were Crohn disease patients and who were controls. The bowel-related questions and Crohn's Disease Activity Index (CDAI) were assessed by gastroenterologists at inclusion in the study. Responses were indicated on a seven-point scale (7 best/1 worst). Mean numeric score was calculated as well as a delta score, i.e. the difference in score between a patient and the matched control.

RESULTS

In 21 of 23 questions the median delta score was zero, indicating no difference between patient and control. The median total delta score was 0.4 in favour of healthy controls (P < 0.001), and significantly higher in patients in relapse, 0.9, than in patients in remission, 0.3 (P < 0.01). The median total numeric score was 5.7 for patients and 6.1 for controls.

CONCLUSIONS

Although patients with Crohn disease scored significantly lower on the quality of life scale than matched healthy controls, the differences were smaller than could be expected, taking the chronic disease into consideration. Disease activity correlated with the quality of life score.

Dipyridamole dilates large cerebral arteries concomitant to headache induction in healthy subjects

Dipyridamole is used for secondary prophylaxis in ischemic stroke and as a vasodilator agent in myocardial scintigraphy. An important side effect to administering dipyridamole is headache. The aim of the current study was to investigate the effects of dipyridamole on cerebral blood flow, large artery diameter, and headache induction. Twelve healthy subjects were included in this single-blind placebo-controlled study in which placebo (0.9% NaCl) and dipyridamole 0.142 mg/kg x min were administered intravenously over 4 minutes 1 hour apart. Blood flow velocity in the middle cerebral artery (Vmax) was recorded by transcranial Doppler and regional cerebral blood flow in the middle cerebral artery (rCBFmca) was measured using single photon emission computed tomography and 133Xenon-inhalation. Blood pressure, heart rate, and pCO2 were measured repeatedly. Headache response was scored every 10 minutes on a verbal scale from 0 to 10 (10 = worst). Dipyridamole caused a decrease in pCO2 (P < 0.001). pCO2 corrected rCBFmca was 41.7 +/- 6.9 mL/100 g x min after placebo versus 41.2 +/- 6.9 after dipyridamole (P > or = 0.05). pCO2 corrected Vmca decreased 8.4% +/- 11.7 (P < 0.001) after dipyridamole, indicating a mean 5.6% +/- 6.7 (P = 0.005) relative increase of the arterial diameter. After dipyridamole the median peak headache score was 2 (range 0 to 7) compared with 0 (range 0 to 3) after placebo (P = 0.02). Dilatation of the middle cerebral artery outlasted the headache response. In conclusion, dipyridamole causes a modest pCO2 independent dilatation of the MCA, which is time-linked to the onset, but not to the cessation, of headache.

Histamine-1 receptor blockade does not prevent nitroglycerin induced migraine. Support for the NO-hypothesis of migraine

It has previously been shown that in migraine sufferers infusion of glyceryl trinitrate (GTN) and histamine causes an immediate headache during the infusion and a genuine migraine attack one to several hours after the infusion. This identical time profile indicates a common mechanism of action. To evaluate whether GTN causes headache via liberation of histamine, we studied the effect of GTN 0.5 micrograms.kg-1.min-1 for 20 min in seven migraine sufferers, once after pretreatment with the histamine-1 (H1)-receptor blocker mepyramine (0.5 mg.kg-1) and once without pretreatment. This mepyramine dose is known to completely abolish histamine-induced headache. After pretreatment with mepyramine five patients experienced migraine, and without pretreatment six patients did so. The median peak headache score was 7 on a 0-10 scale with and without mepyramine pretreatment. The arterial responses, evaluated with transcranial Doppler, were also unaffected by the mepyramine pretreatment. Our results demonstrate that neither headache nor arterial dilatation due to GTN infusion is caused by histamine release. In all likelihood the common mediator of migraine induction by GTN and histamine is nitric oxide.