Association of intravenous thrombolysis and pre-interventional reperfusion: a post hoc analysis of the SWIFT DIRECT trial.

BACKGROUND: A potential benefit of intravenous thrombolysis (IVT) before mechanical thrombectomy (MT) is pre-interventional reperfusion. Currently, there are few data on the occurrence of pre-interventional reperfusion in patients randomized to IVT or no IVT before MT. METHODS: SWIFT DIRECT (Solitaire With the Intention For Thrombectomy Plus Intravenous t-PA vs DIRECT Solitaire Stent-retriever Thrombectomy in Acute Anterior Circulation Stroke) was a randomized controlled trial including acute ischemic stroke IVT eligible patients being directly admitted to a comprehensive stroke center, with allocation to IVT with MT versus MT alone. The primary endpoint of this analysis was the occurrence of pre-interventional reperfusion, defined as a pre-interventional expanded Thrombolysis in Cerebral Infarction score of ≥2a. The effect of IVT and potential treatment effect heterogeneity were analyzed using logistic regression analyses. RESULTS: Of 396 patients, pre-interventional reperfusion occurred in 20 (10.0%) patients randomized to IVT with MT, and in 7 (3.6%) patients randomized to MT alone. Receiving IVT favored the occurrence of pre-interventional reperfusion (adjusted OR 2.91, 95% CI 1.23 to 6.87). There was no IVT treatment effect heterogeneity on the occurrence of pre-interventional reperfusion with different strata of Randomization-to-Groin-Puncture time (p for interaction=0.33), although the effect tended to be stronger in patients with a Randomization-to-Groin-Puncture time >28 min (adjusted OR 4.65, 95% CI 1.16 to 18.68). There were no significant differences in rates of functional outcomes between patients with and without pre-interventional reperfusion. CONCLUSION: Even for patients with proximal large vessel occlusions and direct access to MT, IVT resulted in an absolute increase of 6% in rates of pre-interventional reperfusion. The influence of time strata on the occurrence of pre-interventional reperfusion should be studied further in an individual patient data meta-analysis of comparable trials. TRIAL REGISTRATION NUMBER: clinicaltrials.gov NCT03192332.

Subarachnoid Hemorrhage During Pregnancy and Puerperium: A Population-Based Study.

BACKGROUND: Pregnancy-related subarachnoid hemorrhage (pSAH) is rare, but it causes high mortality and morbidity. Nevertheless, data on pSAH are limited. The objectives here were to examine the incidence trends, causes, risk factors, and outcomes of pSAH in a nationwide population-based cohort study in Finland covering 30 years. METHODS: We performed a retrospective population-based cohort study and nested case-control study in Finland for the period 1987-2016 (Stroke in Pregnancy and Puerperium in Finland). The Medical Birth Register was linked to the Hospital Discharge Register to identify women with incident stroke during pregnancy or puerperium. A subcohort of women with SAH is included in this analysis. The temporal connection of SAH to pregnancy and clinical details were verified from patient records. RESULTS: The unadjusted incidence of pSAH was 3.21 (95% CI, 2.46-4.13) per 100 000 deliveries. No significant increase occurred in the incidence throughout the study period. However, the age of the mother had a significant increasing effect on the incidence. In total, 77% of patients suffered an aneurysmal pSAH, resulting in death in 16.3% of women and with only 68.2% achieving good recovery (modified Rankin Scale score 0-2) at 3 months. Patients with nonaneurysmal pSAH recovered well. The significant risk factors for pSAH were smoking (odds ratio, 3.27 [1.56-6.86]), prepregnancy hypertension (odds ratio, 12.72 [1.39-116.46]), and pre-eclampsia/eclampsia (odds ratio, 3.88 [1.00-15.05]). CONCLUSIONS: The incidence of pSAH has not changed substantially over time in Finland. The majority of pSAH cases were aneurysmal and women with aneurysm had considerable mortality and morbidity. Counseling of pregnant women about smoking cessation and monitoring of blood pressure and symptoms of pre-eclampsia are important interventions to prevent pSAH.

Glutamine synthetase in human carotid plaque macrophages associates with features of plaque vulnerability: An immunohistological study.

BACKGROUND AND AIMS: Glutamine synthetase (GLUL), the sole generator of glutamine, is a metabolic nexus molecule also involved in atherosclerosis. We recently demonstrated a 2.2-fold upregulation of GLUL mRNA in stroke-causing carotid plaques when compared with plaques from asymptomatic patients. Here we compared in the same cohort GLUL mRNA expression with plaque gross morphology, and the colocalization of immunodetectable GLUL protein with histopathological changes and molecular and mechanical mediators linked to plaque development. METHODS: Endarterectomy specimens from 19 asymptomatic and 24 stroke patients were sectioned longitudinally and immunostained for GLUL, CD68, α-smooth muscle actin, iron, heme oxygenase-1 and CD163, and graded semiquantitatively in every 1 mm2. The amounts of cholesterol clefts and erythrocytes were graded. The fibrous cap thickness within each 1 mm2 area was measured. The association between the local pathological findings was analyzed by a hierarchical mixed modelling approach. RESULTS: The previously found correlation between GLUL mRNA and clinical symptomatology was supported by the increased GLUL mRNA in diseased tissue and increased local GLUL immunoreactivity in areas with multiple different atherosclerotic changes. A longer symptom-to-operation time correlated with lower GLUL mRNA (Rs = -0.423, p=0.050) but few outliers had a significantly higher GLUL mRNA levels, which persisted throughout the post-symptomatic period. Plaque ulceration associated with 1.8-fold higher GLUL mRNA (p=0.006). Macrophages were the main GLUL immunoreactive cells. GLUL immunostaining colocalized with erythrocytes, iron, CD163, and heme oxygenase-1. The correlations between local variables were consistent in both asymptomatic and stroke-causing plaques. An inverse correlation was found between the fibrous cap thickness and local GLUL immunoreactivity (p=0.012). Considerable variability in interplaque expression pattern of GLUL was present. CONCLUSIONS: Our results link connect macrophage GLUL expression with carotid plaque features characterizing plaque vulnerability.

Trends in the Incidence and Risk Factors of Pregnancy-Associated Stroke.

Pregnancy is a female-specific risk factor for stroke. Although pregnancy-associated stroke (PAS) is a rare event, PAS leads to considerable maternal mortality and morbidity. It is estimated that 7.7-15% of all maternal deaths worldwide are caused by stroke and 30-50% of surviving women are left with persistent neurological deficits. During last decade, several studies have reported an increasing incidence of PAS. The objective of this review is to summarize studies on time trends of PAS in relation to trends in the prevalence of stroke risk factors in pregnant women. Seven retrospective national healthcare register-based cohort studies from the US, Canada, UK, Sweden, and Finland were identified. Five studies from the US, Canada, and Finland reported an increasing trend of PAS. Potential biases include more sensitive diagnostics and improved stroke awareness among pregnant women and professionals toward the end of the study period. However, the concurrent increase in the prevalence of several stroke risk factors among pregnant women, particularly advanced age, hypertensive disorders of pregnancy, diabetes, and obesity, indicate that the findings are likely robust and should be considered seriously. To reduce stroke in pregnancy, increased awareness among all medical specialties and pregnant women on the importance of risk-factor management during pregnancy and stroke symptoms is necessary. Important preventive measures include counseling for smoking cessation and substance abuse, treatment of hypertensive disorders of pregnancy, use of aspirin in women at high risk for developing preeclampsia, and antithrombotic medication and pregnancy surveillance for women with high-risk conditions. Epidemiological data from countries with a high risk-factor burden are largely missing. National and international registries and prospective studies are needed to increase knowledge on the mechanisms, risk factors, management, and future implications for the health of women who experience this rare but devastating complication of pregnancy.

Carotid Endarterectomy After Intracranial Endovascular Thrombectomy for Acute Ischaemic Stroke in Patients with Carotid Artery Stenosis.

OBJECTIVE: Recent randomised controlled trials demonstrated the benefit of intracranial endovascular thrombectomy (EVT) in acute ischaemic stroke. There is no consensus, however, on how to treat concomitant extracranial carotid artery stenosis after EVT. The aim of this study was to evaluate the outcome in patients treated with carotid endarterectomy (CEA) after EVT, comparing complication rates among patients undergoing CEA for stroke without previous EVT. METHODS: This was a registry study of all patients (n = 3 780) treated with CEA after stroke in Sweden and the capital Helsinki region, Finland, from January 2011 to September 2020. Sixty three patients (1.7%; 0.5% 2011, 4.3% 2019) underwent EVT prior to CEA. The primary outcome was 30 day stroke and death rate. RESULTS: The EVT+CEA group had major stroke as the qualifying neurological event (QNE) in 79%, but just 5.9% had this in the CEA only group (p < .001). Intravenous thrombolysis was administered before EVT in 54% of patients in the EVT+CEA group, but in just 12% in those receiving CEA only (p < .001). The combined stroke and death rate at 30 days for EVT+CEA was 0.0% (95% confidence interval [CI] 0.0 - 5.7). One patient had a post-operative TIA, none had post-operative intracerebral or surgical site haemorrhage. CEA was performed within a median of seven days (interquartile range 4, 15) after QNE, and 75% had CEA ≤14 days from QNE. The main reason to postpone CEA was an infarct larger than one third of the middle cerebral artery territory. The stroke and death rate in patients treated with CEA only was 3.7% (95% CI 3.2 - 4.4), CEA was performed a median of eight days after QNE, and in 79.7% in ≤14 days. The three year survival after EVT+CEA was 93% (95% CI 85 - 100), compared with 87% (95% CI 86 - 88) after CEA only. Cox regression analysis adjusting for age showed no increased all cause mortality after EVT+CEA (HR 1.3, 95% CI 0.6 - 2.7, p = .52). CONCLUSION: These results indicate that CEA is safe to perform after previous successful EVT for acute ischaemic stroke. Results were comparable with those undergoing CEA only, despite the EVT+CEA patients having more severe stroke symptoms prior to surgery, and timing was similar.

Stroke in Pregnancy and Puerperium: Validated Incidence Trends With Risk Factor Analysis in Finland 1987-2016.

OBJECTIVE: To investigate whether previously reported increasing incidence of pregnancy-associated stroke (PAS) is observed in chart-validated register data in Finland. In an exploratory analysis, we studied risk factors for PAS. METHODS: We performed a retrospective population-based cohort study and nested case-control study in Finland from 1987 to 2016. The Medical Birth Register (MBR) was linked to the Hospital Discharge Register to identify women with incident stroke (ischemic stroke, cerebral venous thrombosis, intracerebral or subarachnoid hemorrhage) during pregnancy or puerperium. Cases were verified from patient records. Incidence of PAS over the study period in 5-year age groups and pregnancy/postpartum period was calculated per number of deliveries. Three matched controls were selected for each case from MBR to compare risk factors. RESULTS: After chart review, 29.6% (257 of 868) of cases were PAS. The incidence of PAS was 14.5 (95% confidence interval [CI] 12.8-16.3) per 100,000 deliveries. Incidence increased from 11.1 to 25.2 per 100,000 deliveries from 1987 to 1991 to 2012 to 2016 (p < 0.0001). Incidence increased by age from 9.8 to 29.9 per 100,000 deliveries from 20 to 24 years to >40 years of age (p < 0.0001). During the early postpartum period, incidence was 5-fold greater compared to the first trimester. Maternal mortality was 6.6%. In the multivariable-adjusted model, smoking beyond 12 gestational weeks (odds ratio [OR] 1.8, 95% CI 1.2-2.7), migraine (OR 16.3, 95% CI 5.3-49.8), and hypertensive disorders of pregnancy (OR 4.0, 95% CI 2.5-6.3) were the most important risk factors for PAS. CONCLUSION: PAS incidence is increasing, stressing the importance of careful pregnancy surveillance and risk factor management, particularly in older expectant mothers and extending to puerperium. CLASSIFICATION OF EVIDENCE: This study provides Class III evidence that smoking beyond 12 gestational weeks, migraine, and hypertensive disorders of pregnancy are associated with an increased risk of PAS.

Predictive Factors for Pre-operative Recurrence of Cerebrovascular Symptoms in Symptomatic Carotid Stenosis.

OBJECTIVE: Across stroke subtypes, carotid artery stroke carries the highest risk of recurrence. Despite initiation of best medical therapy (BMT), some patients suffer recurrent neurological events before undergoing carotid endarterectomy (CEA). The aim was to identify clinical predictors of early recurrent events in patients with symptomatic carotid stenosis (sCS) awaiting CEA on modern BMT. METHODS: The Helsinki Carotid Endarterectomy Study 2 (HeCES2) is a cross sectional, longitudinal, prospective, and consecutive cohort study, which enrolled 500 symptomatic or asymptomatic patients with carotid stenosis scheduled for CEA in a tertiary stroke centre. Symptomatic patients were included for this analysis (n = 324). RESULTS: Of all 324 patients with sCS, 39 (12%) had a recurrent cerebrovascular event at a median of six days after the index symptom: four had an ischaemic stroke (1.2%), 16 a hemispheric transient ischaemic attack (TIA; 4.9%), and 19 amaurosis fugax (AFX; 5.9%). The recurrence rate was 4.0 % (n = 13) within 48 h and 9.9% (n = 32) within two weeks. None of the patients (n = 108) presenting with ocular symptoms (AFX or retinal artery occlusion) suffered recurrent hemispheric TIA or stroke. In Cox regression analysis, comorbid hypertension (hazard ratio [HR] 6.58, 95% confidence interval [CI] 1.33-32.47), hemispheric TIA as the index symptom (HR 3.42, 95% CI 1.70-6.90), the number of prior attacks (HR 1.12, 95% CI 1.08-1.15), and high low density lipoprotein/high density lipoprotein ratio (HR 1.51, 95% CI 1.09-2.11) were independently associated with an increased risk of recurrent event, while a history of major cardiovascular event (HR 0.33, 95% CI 0.11-0.96) and high serum fibrinogen level (HR 0.59, 95% CI 0.41-0.86) were associated with a decreased risk. CONCLUSION: More than every tenth patient with sCS experienced an early recurrent cerebrovascular event prior to scheduled CEA, despite optimal medication. However, stroke recurrence was lower than in earlier observational studies, which could be explained by improved care pathways, more aggressive medication, and expedited CEA. All recurrent strokes occurred in patients initially presenting with minor stroke.

Cognitive Dysfunction and Mortality After Carotid Endarterectomy.

Background: Carotid endarterectomy (CEA) has been associated with both postoperative cognitive dysfunction (POCD) and improvement (POCI). However, the prognostic significance of postoperative cognitive changes related to CEA is largely unknown. The aim of this study was to examine the associations between postoperative cognitive changes after CEA and long-term survival. Methods: We studied 43 patients 1 day before CEA as well as 4 days and 3 months after surgery with an extensive neuropsychological test array, and followed them for up to 14 years. POCD and POCI relative to baseline were determined with the reliable change index derived from 17 healthy controls. Associations between POCD/POCI and mortality within the patient group were studied with Cox regression analyses adjusted for confounders. Results: POCD in any functional domain was evident in 28% of patients 4 days after surgery and in 33% of patients 3 months after surgery. POCI was shown in 23% of patients at 4 days and in 44% of patients at 3 months. POCD at 3 months was associated with higher long-term mortality (hazard ratio 5.0, 95% CI 1.8-13.9, p = 0.002) compared with patients with no cognitive decline. Conclusions: Our findings suggest that POCD in a stable phase, 3 months after CEA predicts premature death. Evaluation of postoperative cognitive changes is essential, and POCD in a stable phase after CEA should prompt scrutiny of underlying factors and better adherence to therapies to prevent recurrences and to promote early intervention in imminent deterioration.

The Efficacy of Carotid Surgery by Subgroups: The Concept of Stroke Prevention Potential.

OBJECTIVE: Considering carotid endarterectomy (CEA), reporting treatment delay, symptom status, and surgical complication rates separately gives an incomplete picture of efficacy; therefore, the aim was to combine these factors and develop a reporting standard that better describes the number of potentially prevented strokes. With a real life cohort and theoretical inclusion scenarios, the aim was to explore the stroke prevention potential of different carotid practices. METHODS: Landmark studies for symptomatic and asymptomatic patients were revisited. By using published estimates of treatment effect, a simplified calculator was designed to assess the five year stroke prevention rate per 1000 CEAs (stroke prevention potential [SPP], range 0-478), including the presence and recentness of symptoms, sex, increasing stenosis severity, and complication rates. Patients operated on for carotid stenosis at Helsinki University Hospital (HUH) between 2008 and 2016 were collected from a vascular registry (HUSVASC) and categorised according to the model. The local annual complication rate was re-evaluated and added to the model. The HUH patient cohort was incorporated into the SPP model, and changes over time analysed. Finally, theoretical changes in patient selection were compared in order to explore the theoretical impact of patient selection and shortening of the delay. RESULTS: Fifteen hundred and five symptomatic and 356 asymptomatic carotid stenoses were operated on with stroke plus death rates of 3.6% and 0.3%, respectively. The proportion of CEAs performed within two weeks of the index event increased over the follow up period, being 77% in 2016. The SPP increased from 123 in 2008 to 229 in 2016. Theoretically, 350 ischaemic strokes were prevented in the period 2008-16, with 1861 CEAs. CONCLUSIONS: National and international comparison of different CEA series is irrelevant if the inclusion criteria are not considered. A calculator that is easy to apply to large scale high quality registered data was developed and tested. SPP was found to increase over time, which is a probable sign of improved patient selection and an increased number of strokes prevented by the CEAs performed.

Prior Intravenous Stroke Thrombolysis Does Not Increase Complications of Carotid Endarterectomy.

Background and Purpose- Carotid endarterectomy (CEA) is recommended within 14 days after carotid artery stroke to prevent recurrence. However, the optimal timing of CEA after intravenous thrombolysis (IVT) remains unclear. We studied the safety of CEA after IVT while taking into account both stroke recurrence and CEA-related complications. Methods- Patients who underwent IVT followed by CEA in Helsinki University Hospital 2005 to 2016 were withdrawn from prospectively collected registers. The incidence of stroke recurrence during the time between IVT and CEA, peri/postoperative stroke, hyperperfusion syndrome or drug-resistant high blood pressure, and 3-month outcome measured by modified Rankin Scale was recorded. Stroke patients treated with CEA without preceding IVT were used as controls. Results- Altogether 128 CEAs with preceding IVT and 777 CEAs for stroke without IVT were identified. The median time from IVT to CEA was 9 days (range, 0-349 days; interquartile range, 16). Seven patients (5.5%) underwent CEA within 24 hours, 20 (15.6%) within 48 hours and 87 (68.0%) within 2 weeks from IVT. Stroke recurrence in IVT-CEA patients was 5.5% at median 4 days after IVT (range, 0-8 days). Outcome from CEAs performed within 48 hours from IVT did not differ from CEAs performed later with respect to peri/postoperative ischemic strokes (5.0% and 3.7%), hemorrhagic strokes (5.0% and 1.9%), neck hematomas (5.0% and 8.3%), myocardial infarctions (0.0% and 0.9%), or 3-month modified Rankin Scale. There was a tendency toward higher incidence of hyperperfusion syndrome in the patients operated within 48 hours from IVT (20.0% versus 6.5%; P=0.070). The CEA-related stroke rate was similar to that of the operation without thrombolysis. Only smoking was significantly associated with peri/postoperative stroke (odds ratio, 21.82; 95% confidence interval, 1.08-439.58). Conclusions- Time between IVT and CEA was not associated with CEA-related complications. The high rate of stroke recurrence during the waiting time for CEA underscores the importance of shortening surgery delays.

Low-expression variant of fatty acid-binding protein 4 favors reduced manifestations of atherosclerotic disease and increased plaque stability.

BACKGROUND: Fatty acid-binding protein 4 (FABP4 or aP2 in mice) has been identified as a key regulator of core aspects of cardiometabolic disorders, including lipotoxic endoplasmic reticulum stress in macrophages. A functional promoter polymorphism (rs77878271) of human FABP4 gene has been described resulting in reduced FABP4 transcription. METHODS AND RESULTS: We investigated the effects of this low-expression variant of FABP4 on cardiovascular morbidity and carotid atherosclerosis on a population level (n=7491) and in patient cohorts representing endarterectomized patients with advanced carotid atherosclerosis (n=92) and myocardial infarction (n=3432). We found that the low-expression variant was associated with decreased total cholesterol levels (P=0.006) with the largest reduction in variant allele homozygotes. Obese variant allele carriers also showed reduced carotid intima-media thickness (P=0.010) and lower prevalence of carotid plaques (P=0.060). Consistently, the variant allele homozygotes showed 8-fold lower odds for myocardial infarction (P=0.019; odds ratio, 0.12; 95% confidence interval, 0.003-0.801). Within the carotid plaques, the variant allele was associated with a 3.8-fold reduction in FABP4 transcription (P=0.049) and 2.7-fold reduction in apoptosis (activated caspase 3; P=0.043). Furthermore, the variant allele was enriched to patients with asymptomatic carotid stenosis (P=0.038). High FABP4 expression in the carotid plaques was associated with lipid accumulation, intraplaque hemorrhages, plaque ulcerations, and phosphoactivated endoplasmic reticulum stress markers. CONCLUSIONS: Our results reveal FABP4 rs77878271 as a novel variant affecting serum total cholesterol levels and cardiovascular risk. A therapeutic regimen reducing FABP4 expression within the atherosclerotic plaque may promote lesion stability through modulation of endoplasmic reticulum stress signaling, and attenuation of apoptosis, lipid burden, and inflammation.

Adipophilin expression is increased in symptomatic carotid atherosclerosis: correlation with red blood cells and cholesterol crystals.

BACKGROUND AND PURPOSE: Adipophilin is an adipose differentiation-related protein expressed in lipid-containing cells. Using DNA microarray analysis, we previously found the adipophilin gene (ADFP) to be overexpressed in symptomatic carotid plaques (CP). This led us to further examine the role of adipophilin in carotid atherosclerosis relative to symptom status. METHODS: Ninety-eight high-grade (>70%) CPs were obtained in carotid endarterectomy. The relative expression of ADFP mRNA was measured by quantitative real-time RT-PCR, and the relative amount of adipophilin protein was quantified with Western blotting. Detailed topographical correlations with extravasated red blood cells and extracellular cholesterol crystals were obtained by means of immunohistochemistry. RESULTS: The relative expression of ADFP mRNA was increased in symptomatic compared with asymptomatic CPs at both the mRNA level (1.82+/-0.19[SE] versus 1.25+/-0.15, P=0.012) and the protein level (1.04+/-0.23 versus 0.46+/-0.14, P=0.043). Adipophilin colocalized with macrophage foam cells, extravasated red blood cells (P<0.0001), and cholesterol crystals (P<0.0001), and its expression associated with macroscopic ulceration of CP (P<0.0001). CONCLUSIONS: Intraplaque hemorrhages may contribute to intracellular lipid accumulation and consequent adipophilin expression. Because adipophilin blocks cholesterol efflux from lipid-laden cells, they may die and develop a necrotic lipid core, thereby destabilizing the plaque.

Endothelial apoptosis does not determine symptom status in carotid artery disease.

BACKGROUND: We examined the hypothesis that endothelial denudation in advanced carotid plaques (CPs) occurs by increased apoptosis of endothelial cells (ECs) using scanning electron microscopy (SEM) as well as markers of cellular proliferation and apoptosis in advanced symptomatic CPs (SCPs) and asymptomatic CPs (ACPs). METHODS: 93 consecutive patients underwent carotid endarterectomy. Five additional specimens were studied by SEM. We performed TUNEL assays, and immunostaining against Fas receptor (FasR), Fas ligand (FasL), activated caspase 3 (ACA3) and Ki-67. RESULTS: SEM revealed morphological changes consistent with EC detachment. Surprisingly, ACA3 positivity was more pronounced on the endothelium of ACPs (4.6 +/- 0.7% of total EC count) than on SCPs (3.3 +/- 0.7%, p = 0.049), and was found to correlate positively with nuclear Ki-67 expression (r(s) = 0.275, p = 0.040). FasL expression was significantly increased on the endothelium of SCPs compared with ACPs (66.4 +/- 4.4 vs. 53.9 +/- 4.5%, p = 0.047). CONCLUSIONS: Absence of increased positivity of apoptotic markers dismisses apoptosis as a dominant mechanism underlying endothelial detachment of SCPs. Rather, increased ACA3 with co-expression of Ki-67 in ACPs might suggest that renewal of endothelium by active cell turnover may contribute to clinically silent evolution of plaques with preserved EC integrity. These observations may assist in designing novel therapies to prevent endothelial decay and symptom generation in advanced carotid artery disease.

Apoptosis dominant in the periinfarct area of human ischaemic stroke--a possible target of antiapoptotic treatments.

Animal experiments have suggested that apoptotic programmed cell death is responsible for an important portion of the delayed ischaemic brain damage. Antiapoptotic signalling through erythropoietin (EPO) binding to its receptor (EPOR) is triggered by systemic or local hypoxia and may exist in the post-ischaemic brain, and a neuroprotective effect by EPO was described recently and proposed for clinical stroke treatment. The objective of the study was to determine whether apoptosis occurs in human ischaemic stroke and to describe its topographical distribution. An autopsy cohort consisting of 13 cases of fatal ischaemic stroke (symptom duration from 15 h to 18 days) treated at the Department of Neurology, Helsinki University Central Hospital and 3 controls were studied. DNA damage was investigated by immunofluorescent TUNEL-labelling in combination with apoptotic cell morphology and by visualization of a major signalling system of apoptosis, Fas-FasL (Fas-ligand), by the immunoperoxidase technique. The relationship of EPO and EPOR in the face of TUNEL-labelled and necrotic cell death was co-registered in human cerebral neurons undergoing different stages of ischaemic change. TUNEL-labelled cells with apoptotic morphology were disproportionately more frequent, 148% (30) [mean (SE)] in the periinfarct versus 97% (22) in the core, as percentage of the cells in the contralateral hemisphere (P = 0.027). The apoptotic cell percentage reached up to 26% (2) of all cells in periinfarct area. A linear correlation was found for Fas and its counterpart FasL expression (r(S) = 0.774, P < 0.001). Ischaemia induced widespread neuronal expression of EPOR, which was inversely related to the severity of ischaemic neuronal necrosis (P < 0.05). To conclude, these data verify the predominance of apoptosis in the periphery of human ischaemic infarctions. Fas and FasL were linearly overexpressed supporting that this 'death-receptor' complex may promote the completion of cell death. Increased EPO signalling may be a cellular response for survival in less severely damaged areas. These results support antiapoptotic therapies against delayed neuronal cell death in human ischaemic stroke.