Differences in Clinical Characteristics between Patients with Transient Ischemic Attack Whose Symptoms Do and Do Not Persist on Arrival.

BACKGROUND: Symptoms of transient ischemic attack (TIA) persist on arrival and subsequently resolve in some patients admitted to hospitals early after onset. Differences in clinical characteristics between patients with acute TIA whose symptoms do and do not persist on arrival remain unclear. METHODS: We retrospectively extracted data of consecutive TIA patients with an onset-to-door time (ODT) of 24 hours or less and without a history of stroke from a multicenter TIA database. Clinical characteristics were compared between patients with and without persisting symptoms on arrival. RESULTS: Two hundred sixty-six patients (158 men, 68.0 ± 12.9 years) were included. Of the total number of patients, 105 (39.5%) had persisting symptoms with a mean National Institutes of Health Stroke Scale score of 2.4 (median, 1.0). Patients with persisting symptoms were more likely to have sensory disorder, ambulance-transported admission, long-duration TIA (≥60 minutes), and shorter ODT than those without. Multivariate analysis showed that sensory disorder (odds ratio [OR] 2.52, 95% confidence interval [CI] 1.35-4.77), ambulance-transported admission (OR 1.80, 95% CI 1.00-3.28), and long-duration TIA (OR 3.96, 95% CI 2.12-7.71) were positively associated and that an ODT of more than 12 hours (OR .18, 95% CI .04-.63) was inversely associated with the presence ofpersisting symptoms. Patients with persisting symptoms were more likely to be examined by a stroke physician at first (69% versus 57%, P = .049) and then hospitalized in a stroke unit (59% versus 43%, P = .010). CONCLUSION: Clinical manifestations and management after admission might differ between patients with acute TIA whose symptoms do and do not persist on arrival.

Factors associated with onset-to-door time in patients with transient ischemic attack admitted to stroke centers.

BACKGROUND AND PURPOSE: The aim of this study was to elucidate the factors associated with the time from symptom onset to arrival at a stroke center (onset-to-door time [ODT]) in patients with classically defined transient ischemic attack using data from a multicenter, retrospective study. METHODS: The subjects were patients with transient ischemic attack admitted to 13 stroke centers in Japan within 7 days of onset between 2008 and 2009. A total of 464 patients registered (292 men, 68.5±13.2 years old), and 421 of them (268 men, 68.8±13.1 years old) were included in the analyses. ODT was classified into the following 5 categories: <3 hours, 3 to 6 hours, 7 to 12 hours, 13 to 24 hours, and >24 hours. RESULTS: There were 233 patients (55.3%) who visited a stroke center within 3 hours of symptom onset. Multiple ordinal logistic regression analysis revealed that motor weakness, speech disturbance, and duration of symptoms >10 minutes were independently associated with a short ODT. Furthermore, a history of transient ischemic attack and hypertension and a referral from another medical facility were independently associated with a long ODT. Patients with a higher ABCD2 score were likely to arrive at a stroke center more quickly. CONCLUSIONS: We identified several factors that were positively and negatively associated with the ODT in patients with transient ischemic attack.

Incidence and predictors of ischemic stroke events during hospitalization in patients with transient ischemic attack.

BACKGROUND: The purpose of this study was to elucidate the incidence and predictors of ischemic stroke or recurrent transient ischemic attack (TIA) during acute hospitalization in patients with TIA. METHODS: We carried out a multicenter retrospective study to clarify the characteristics of in-patients with TIA. The subjects of this study were TIA patients admitted to 13 stroke hospitals within 7 days after onset between 2008 and 2009. TIA was defined as focal neurologic symptoms ascribable to a vascular etiology lasting less than 24 h. We investigated the incidence and predictors of ischemic events including ischemic stroke or recurrent TIA during hospitalization. RESULTS: A total of 464 patients with TIA (292 men, 69 ± 13 years) were registered. Of those, 400 (86.2%) were admitted within 24 h of TIA onset. The mean length of hospital stay was 13 days. During hospitalization, 8 patients had ischemic strokes and 26 had recurrent TIAs. The leading subtype of 8 ischemic strokes was small vessel disease (n = 3) followed by cardioembolism (n = 2). Multiple logistic regression analysis showed that hypertension (OR: 3.41; 95% CI: 1.23-12.3), MRI-diffusion-weighted image positivity (OR: 2.49; 95% CI: 1.15-5.25), and hemiparesis (OR: 2.30; 95% CI: 1.02-5.88) were independently associated with ischemic events during hospitalization. CONCLUSIONS: In this study, 1.7% of patients with TIA had ischemic stroke during acute hospitalization, and the most common subtype was small vessel disease. Subsequent ischemic stroke and recurrent TIA were associated with hypertension, positive DWI findings, and hemiparesis.

Features of patients with transient monocular blindness: a multicenter retrospective study in Japan.

BACKGROUND: Transient monocular blindness (TMB) is associated with a transient ischemic attack (TIA). The purpose of this study was to investigate the features of TMB in the Japanese population using data from a multicenter retrospective study of TIA. METHODS: The subjects were consecutive TIA patients admitted to 13 stroke centers within 7 days after symptom onset. We compared clinical characteristics of patients with TMB and those without TMB who had other symptoms of cerebral TIA. RESULTS: A total of 464 patients were registered between January 2008 and December 2009, and 444 patients (283 men, mean age: 68.5 years) were included in the analysis. Thirteen patients (2.9%) presented with TMB. Patients with TMB were less likely to arrive at the specialized stroke center quickly than those without TMB (P = .013). Stenotic lesions in the extracranial internal carotid artery were more common in patients with TMB (33.3% versus 9.1%, P = .022). CONCLUSIONS: TMB was not common in our TIA inpatients. This study suggests that patients with TMB should immediately undergo a diagnostic workup, including brain and vessel imaging, and cardiac evaluation, as is performed in patients with other cerebral TIA symptoms. A larger, prospective cohort is needed to confirm the risks and outcomes of patients with TMB in the Japanese population.

Seasonal variation of stroke incidence in Japan for 35631 stroke patients in the Japanese Standard Stroke Registry, 1998-2007.

BACKGROUND: Seasonal variation of stroke incidence has been reported in many countries. The present study was designed to elucidate seasonal and monthly variations in the incidence of subtypes of acute ischemic stroke and hypertensive hemorrhagic stroke using the Japanese Standard Stroke Registry Study (JSSRS) database, which is currently the world's largest hospital-based stroke database, accumulating records from 163 Japanese institutions. METHODS: Among 47,782 patients with acute stroke registered with JSSRS between 1998 and 2007, we selected 35,631 for analysis (patients with ischemic or hemorrhagic stroke of unknown etiology were excluded). A simple moving average was used to examine monthly variation of stroke incidence. We also examined seasonal variation of ischemic stroke subtypes. RESULTS AND CONCLUSIONS: Monthly variation in incidence of all ischemic stroke was significant (P < .001). Noncardioembolic ischemic stroke was more frequent in summer than in winter (P < .001). Lacunar stroke showed higher incidence in summer than in winter (P < .001), although the increase did not reach significance for atherothrombotic stroke (P = .057). In contrast, cardioembolic stroke (P < .001) and hemorrhagic stroke (P < .001) occurred more frequently in winter than in summer. Hemorrhagic stroke showed a regional difference of incidence between northern and southern Japan. There is a temporal variation of stroke incidence in Japan, with different patterns of variation depending on stroke subtype. These findings may help in developing strategies for preventing stroke.

Phase I study of intravenous low-dose granulocyte colony-stimulating factor in acute and subacute ischemic stroke.

BACKGROUND: Granulocyte colony-stimulating factor (G-CSF; filgrastim) may be useful for the treatment of acute ischemic stroke because of its neuroprotective and neurogenesis-promoting properties, but an excessive increase of neutrophils may lead to brain injury. We examined the safety and tolerability of low-dose G-CSF and investigated the effectiveness of G-CSF given intravenously in the acute phase (at 24 hours) or subacute phase (at 7 days) of ischemic stroke. METHODS: Three intravenous dose regimens (150, 300, or 450 µg/body/day, divided into 2 doses for 5 days) of G-CSF were examined in 18 patients with magnetic resonance imaging (MRI)-confirmed infarct in the territory of the middle cerebral artery. Nine patients received the first dose at 24 hours poststroke (acute group) and 9 patients received the first dose on day 7 poststroke (subacute group; n = 3 at each dose in each group). A scheduled administration of G-CSF was skipped if the patient's leukocyte count exceeded 40,000/µL. Patients received neurologic and MRI examinations. RESULTS: We found neither serious adverse event, drug-related platelet reduction nor splenomegaly. Leukocyte levels remained below 40,000/µL at 150 and 300 µg G-CSF/body/day, but rose above 40,000/µL at 450 µg G-CSF/body/day. Neurologic function improvement between baseline and day 90 was more marked after treatment in the acute phase versus the subacute phase (Barthel index 49.4 ± 28.1 v 15.0 ± 22.0; P < .01). CONCLUSIONS: Low-dose G-CSF (150 and 300 µg/body/day) was safe and well tolerated in ischemic stroke patients, and leukocyte levels remained below 40,000/µL.

Examination timing and lesion patterns in diffusion-weighted magnetic resonance imaging of patients with classically defined transient ischemic attack.

BACKGROUND: This study investigated factors associated with the presence of acute ischemic lesions after transient ischemic attack (TIA), using diffusion-weighted imaging (DWI) data from a multicenter retrospective, observational study. METHODS: Of the 464 patients admitted to 13 stroke centers in Japan within 7 days after TIA onset, 458 patients underwent a DWI examination in this registry. Patients were divided into those with acute ischemic lesions and those without. We analyzed associations between DWI lesions and baseline characteristics, including age, sex, comorbidities, large artery atherosclerosis (LAA), type and duration of symptoms, the presence of multiple occurrences of TIA within 90 days before hospital visits (multiple TIAs) and the time from symptom onset to DWI examination (time-to-DWI). RESULTS: Among the 458 patients (291 men, 68.4±13.2 years old), 374 (81.7%) underwent a DWI examination within the initial 24 hours after the symptom onset. DWI lesions were found in 96 patients (21.0%), and divided into a single lesion (56 patients, 12.2%) or multiple lesions (40 patients, 8.7%). The presence of DWI lesions had an association with male sex (odds ratio [OR] 1.84; 95% confidence interval [CI] 1.07-3.29), time-to-DWI longer than 24 hours (OR 2.96; CI 1.57-5.52), and intracranial LAA (OR 1.99; CI 1.02-3.79). The presence of a single DWI lesion had an association with atrial fibrillation (OR 2.70; CI 1.41-5.03), and multiple DWI lesions did with time-to-DWI longer than 24 hours (OR 6.20; CI 2.60-15.20), multiple TIAs (OR 3.04; CI 1.35-6.76), intracranial LAA (OR 3.63; CI 1.44-8.89), and extracranial LAA (OR 3.53; CI 1.08-10.78). CONCLUSIONS: Acute ischemic lesions on DWI were associated with time-to-DWI and LAA in patients with classically defined TIA. Additionally, we identified some differences in relating factors between patients with single and multiple DWI lesions. These results indicate that time-to-DWI and DWI lesion pattern may be important for the diagnosis and management of TIA.

Inositol hexakisphosphate kinases induce cell death in Huntington disease.

Inositol pyrophosphate diphosphoinositol pentakisphosphate is ubiquitously present in mammalian cells and contains highly energetic pyrophosphate bonds. We have previously reported that inositol hexakisphosphate kinase type 2 (InsP(6)K2), which converts inositol hexakisphosphate to inositol pyrophosphate diphosphoinositol pentakisphosphate, mediates apoptotic cell death via its translocation from the nucleus to the cytoplasm. Here, we report that InsP(6)K2 is localized mainly in the cytoplasm of lymphoblast cells from patients with Huntington disease (HD), whereas this enzyme is localized in the nucleus in control lymphoblast cells. The large number of autophagosomes detected in HD lymphoblast cells is consistent with the down-regulation of Akt in response to InsP(6)K2 activation. Consistent with these observations, the overexpression of InsP(6)Ks leads to the depletion of Akt phosphorylation and the induction of cell death. These results suggest that InsP(6)K2 activation is associated with the pathogenesis of HD.

Relationship between chronic kidney disease and white matter hyperintensities on magnetic resonance imaging.

Renal dysfunction may be related to cerebral small-vessel disease. This study aimed to assess the relationship between mild renal dysfunction and various white matter hyperintensities on magnetic resonance imaging (MRI). A total of 2106 subjects (1368 men and 738 women; mean age, 56 ± 10 years) without a history of stroke were enrolled in the study. Kidney function was evaluated in terms of estimated glomerular filtration rate (eGFR), calculated using the relationship 194Cr(-1.094) × age(-0.287) × 0.739 (if female), where Cr is serum creatinine concentration. White matter hyperintensity on T2-weighted MRI was classified as deep and/or subcortical white matter hyperintensity (DSWMH), periventricular hyperintensity (PVH), or asymptomatic cerebral infarction (ACI). The prevalence of ACI, DSWMH, and PVH was significantly correlated with degree of eGFR reduction; in the subgroups with eGFR ≥ 90, 60∼89, and <60 mL/min/1.73 m(2), the following prevalences were found: ACI, 7%, 6%, and 16%; DSWMH, 18%, 21%, and 37%; PVH: 7%, 10%, and 21%. The odds ratios for ACI, DSWMH, and PVH of eGFR <60 mL/min/1.73 m(2) were significantly increased, to 2.11 (95% confidence interval [CI], 1.23-3.61; P = .006), 2.26 (1.53-3.34; P < .001), and 2.81 (1.67-4.72; P < .001), respectively. Our data indicate that mild renal dysfunction may be associated with an increase in cerebral small-vessel disease independent of hypertension.

Chronic kidney disease in patients with ischemic stroke.

To examine the significance of renal dysfunction in patients who have sustained ischemic stroke, we examined the relationship between the renal function evaluated in terms of estimated glomerular filtration rate (eGFR) and the subtype of brain infarction (BI) in patients with ischemic stroke. A total of 639 patients with BI were enrolled in this study, with 314 subjects without stroke or transient ischemic attack registered as age-matched controls. eGFR was calculated according to the equation 194 × Cr(-1.094) × Age(-0.287) (-0.739 if female), where Cr is serum creatinine concentration, and was classified into four stages: stage I, eGFR ≥ 90 mL/min/1.73 m(2); stage II, eGFR 60 ~ 89 mL/min/1.73 m(2); stage III, eGFR 30 ~ 59 mL/min/1.73 m(2); and stage IV, eGFR <29 mL/min/1.73 m(2). Stage III-IV was significantly more prevalent in the BI group (38%) than in the control group (22%; P < .001). The odds ratio for stage III-IV was significantly higher in the BI group (1.93; 95% confidence interval [CI], 1.35-2.76). Among the BI subgroups, the odds ratios of stage III-IV for the atherothrombotic type (1.81; 95% CI, 1.23-2.68) and the cardiogenic type (2.25; 95% CI, 1.32-3.83) were significantly higher than that of the control group, but that of stage III-IV for lacunar type was not (1.67; 95% CI, 0.98-2.84). Our results indicate that ischemic stroke is frequently associated with renal dysfunction. Chronic kidney disease might be independent risk factor for infarction, especially for cardiogenic and atherosclerotic types.

Effect of edaravone on the estimated glomerular filtration rate in patients with acute ischemic stroke and chronic kidney disease.

The oxygen free radical scavenger edaravone is used in patients with acute ischemic stroke in Japan, but adverse reactions, especially decreased renal function, have raised concerns. To examine whether a patient's estimated glomerular filtration rate (eGFR) at admission can predict renal function deterioration after edaravone treatment, we retrospectively evaluated the effect of edaravone on eGFR in Japanese patients with acute ischemic stroke and chronic kidney disease (CKD). The baseline eGFR in the edaravone-treated group (73.5±20.3 mL/min/1.73 m(2); n=408) at admission was significantly (P < .05) higher than that in the non-edaravone-treated group (51.9±25.2 mL/min/1.73 m(2); n=41). The change in eGFR after treatment was categorized into 3 grades: nonexacerbation (≤10%), 10%-30% exacerbation, and >30% exacerbation. There was no significant difference in exacerbation grade between the edaravone-treated and non-edaravone-treated groups (χ(2) =3.134; P=.21). We next subdivided the edaravone-treated group according to eGFR at admission as either CKD (eGFR <60 mL/min/1.73 m(2); n=111) and non-CKD (n=297). No significant decrease in eGFR was seen even in the edaravone-treated CKD group (most of whom were in stage 3 CKD). Decreased eGFR in stroke patients was found to be associated with stroke subtype (cardiogenic stroke), but not with infection. The present study demonstrates that eGFR at admission is not a good predictor of renal deterioration in edavarone-treated acute ischemic stroke patients, including those with stage 3 CKD.

Platelet aggregates detected by a conventional hematology analyzer method is a risk factor for stroke or a predictive factor in patients with chronic-stage cerebral infarction.

Assessment of platelet activation and/or function is important for primary and secondary prevention of vascular events. To test the hypothesis that determination of platelet aggregation in patients with chronic-stage cerebral infarction (CI) provides a simple measure of risk for ischemic stroke, we used a conventional hematology analyzer to detect aggregates and to assess the efficacy of antiplatelet agents in preventing spontaneous aggregate formation. Platelet aggregates were measured in citrated blood from 142 magnetic resonance imaging confirmed CI patients and 97 controls without CI (nonstroke). Aggregates were detected in 1 of 36 (2.8%) nonstroke subjects without risk factors, but in 24 of 52 (46.2%) nonstroke subjects with risk factors (odds ratio [OR], 3.32; 95% confidence interval [CI], 1.10-10.00), in 21 of 35 (60.0%) nonstroke subjects with a predictive factor (carotid artery intima-media thickness [IMT] >1.1 mm) (OR, 9.13; 95% CI, 2.70-30.48), and in 31 of 63 (49.2%) CI patients who had not received antiplatelet therapy (OR, 2.16; 95% CI, 1.12-4.17). After adjusting for other risk factors, the appearance of platelet aggregates was correlated only with IMT ≥1.1 mm. The rate of appearance of platelet aggregates was 0.33-fold lower in patients on antiplatelet therapy compared with those not on antiplatelet therapy (24.1%; 19 of 79 CI patients). Patients with platelet aggregates in the blood are considered at high risk for ischemic stroke, because the appearance of aggregates is associated with increased IMT. Our method is suitable for screening platelet function in high-risk patients and for examining the efficacy of antiplatelet agents.

Investigation of antiphosphatidyl-serine antibody and antiphosphatidyl-inositol antibody in ischemic stroke patients.

Antiphospholipid syndrome is characterized by arterial or venous thrombosis and the presence of antiphospholipid antibodies (aPL). We measured ß2-GPI aCL, IgGaCL, LA, antiphosphatidyl-serine antibody (PS), and antiphosphatidyl-inositol antibody (PI) in each patient at one month after the onset of stroke. In addition, carotid artery echography was performed in patients positive for PI or PS. Among the 250 patients, 13.6% (34/250) were positive for either PI or PS, and 6.8% (17/250) were positive for both. Carotid artery echography performed on these 34 patients showed that the frequencies of increased intimal-medial thickness (IMT) of 1.1 mm or more, plaque, and carotid artery stenosis of 50% or more were all significantly higher in patients positive for antinuclear antibody than those negative for the antibody (P < .05). PI and PS are associated with antinuclear antibody and precipitation of atherosclerosis. Ischemic stroke patients with SLE frequently showed a variety of antiphospholipid-protein antibodies.

Comparison between single antiplatelet therapy and combination of antiplatelet and anticoagulation therapy for secondary prevention in ischemic stroke patients with antiphospholipid syndrome.

Satisfactory results have not yet been obtained in therapy for secondary prevention in ischemic stroke patients with antiphospholipid syndrome (APS). We therefore compared single antiplatelet therapy and a combination of antiplatelet and anticoagulation therapy for secondary prevention in ischemic stroke patients with APS.The subjects were 20 ischemic stroke patients with antiphospholipid antibody, 13 with primary antiphospholipid syndrome and 7 with SLE-related antiphospholipid syndrome. Diagnosis of APS was based on the 2006 Sydney criteria. Eligible patients were randomly assigned to either single antiplatelet therapy (aspirin 100 mg) or a combination of antiplatelet and anticoagulation therapy (target INR: 2.0-3.0; mean 2.4+/-0.3) for the secondary prevention of stroke according to a double-blind protocol. There was no significant difference between the two groups in age, gender, NIH Stroke Scale on admission, mRS at discharge, or rate of hypertension, diabetes mellitus, hyperlipidemia, or cardiac disease. We obtained Kaplan-Meier survival curves for each treatment. The primary outcome was the occurrence of stroke. The mean follow-up time was 3.9+/-2.0 years. The cumulative incidence of stroke in patients with single antiplatelet treatment was statistically significantly higher than that in patients receiving the combination of antiplatelet and anticoagulation therapy (log-rank test, p-value=0.026). The incidence of hemorrhagic complications was similar in the two groups. The recent APASS study did not show any difference in effectiveness for secondary prevention between single antiplatelet (aspirin) and single anticoagulant (warfarin) therapy. Our results indicate that combination therapy may be more effective in APS-related ischemic stroke.

[Recurrent idiopathic cerebral infarction in a 5-year-old boy, with emphasis on the importance of platelet aggregation analysis for appropriate selection of anti-platelet drugs].

We present a 5-year-old boy with recurrent idiopathic cerebral infarction in which analysis of platelet hyperaggregability was useful in choosing appropriate anti-platelet drugs. The patient presented with gait disturbance at the age of 5 years and 1 month. Brain MRI demonstrated multiple infarctions in the right thalamus and left cerebellum. There were no apparent underlying diseases including hematological, cardiac and vascular abnormalities. He was diagnosed as idiopathic cerebral infarction. First, we administered ticlopidine and he remained stable with persistent mild intention tremor in the left upper extremity for 4 months. Then he developed the second stroke at the age of 5 years and 5 months, and multiple infarctions in the right celebellum and cerebellar vermis were demonstrated. On platelet aggregation analysis, adenosine diphosphate (ADP)-induced aggregation was inhibited, probably due to ticlopidine administration. Collagen- and epinephrine-induced platelet aggregation showed hyperaggregation, so we started to administer cilostazol, which inhibits only epinephrine-induced hyperaggregation. We also added aspirin, which inhibits collagen-induced hyperaggregation. The combination of anti-platelet drugs inhibited epinephrine-, collagen- and ADP-induced hyperaggregation in this patient. He has been stable on the triple combination of anti-platelet drugs without further episodes of cerebral infarction or transient ischemic attack for 4 years to date. Appropriate selection of anti-platelet therapy was achieved by the simple and repeatable platelet aggregation analyses, which must be considered even in pediatric patients with cerebral infarction.

The role of high-sensitivity C-reactive protein in asymptomatic intra- and extracranial large artery diseases.

BACKGROUND: It remains unclear whether high-sensitivity CRP (hs-CRP) is predictive of atherosclerosis in the intracranial artery. The aim of this study is to assess the role of hs-CRP in asymptomatic intracranial artery occlusive diseases. METHODS: Of the 3,366 apparently healthy subjects who received a brain checkup, 138 with > or =25% intracranial artery stenosis on magnetic resonance angiography, 267 with > or =25% extracranial carotid artery stenosis on B-mode ultrasonography and 435 without intracranial artery or extracranial carotid artery stenosis (age-matched controls) were selected for this study. RESULTS: The mean CRP concentration in the subjects with intracranial artery stenosis was not significantly different from that in the control subjects, and the differences of mean CRP concentrations among the subgroups with 25-49, 50-74 and 75% or greater stenosis in the intracranial artery were not significant. The odds ratios of hs-CRP for extracranial carotid artery stenosis tended to increase with increasing CRP concentrations, but those of hs-CRP for intracranial artery stenosis showed no significant difference. CONCLUSION: The degree of atherogenic inflammation in asymptomatic intracranial artery stenosis may be less than that in extracranial carotid artery stenosis.

[Case of juvenile stroke caused by methylenetetrahydrofolate reductase deficiency].

The patient had suffered from left hemiparesis at the age of thirteen months, and acute ischemic stroke of unknown etiology had been diagnosed at that time. His hemiparesis gradually disappeared and he was discharged two weeks after the onset without disability. At the age of 17 years, MRI following minor head trauma revealed cerebral infarctions located at the right corona radiata and basal ganglia. Laboratory findings showed hyperhomocysteinemia. Genetic study disclosed methylenetetrahydrofolate reductase deficiency (MTHFRD) (valine/valine type). MTHFRD is not detected by the routine infantile mass screening test for congenital amino acid metabolic disease, and should be considered in any patient with ischemic stroke at under two years of age.

Administration of hematopoietic cytokines in the subacute phase after cerebral infarction is effective for functional recovery facilitating proliferation of intrinsic neural stem/progenitor cells and transition of bone marrow-derived neuronal cells.

BACKGROUND: Hematopoietic cytokines, granulocyte colony-stimulating factor (G-CSF), and stem cell factor (SCF) were reported to show a neuroprotective effect or to support neurogenesis. These cytokines also mobilize bone marrow (BM) cells into the brain, and the BM-derived cells differentiate into neuronal cells. We administered these hematopoietic cytokines after focal cerebral ischemia and assessed their effects and the therapeutic time window for neuronal regeneration. METHODS AND RESULTS: We induced permanent middle cerebral artery occlusion in mice whose BM had been replaced with BM cells from green fluorescent protein (GFP)-transgenic mice. The occluded mice were treated with G-CSF and SCF in the acute phase (days 1 to 10) or subacute phase (days 11 to 20), and the brain functions and histological changes were evaluated. Separately, we injected bromodeoxyuridine during cytokine treatment to assess cell kinetics in the brain. Six mice were prepared for each experimental group. Administration of G-CSF and SCF in the subacute phase effectively improved not only motor performance but also higher brain function, compared with acute-phase treatment. Acute-phase and subacute-phase treatments identically reduced the infarct volume relative to vehicle treatment. However, subacute-phase treatment significantly induced transition of BM-derived neuronal cells into the peri-infarct area and stimulated proliferation of intrinsic neural stem/progenitor cells in the neuroproliferative zone. CONCLUSIONS: Administration of G-CSF and SCF in the subacute phase after focal cerebral ischemia is effective for functional recovery, enhancing cytokine-induced generation of neuronal cells from both BM-derived cells and intrinsic neural stem/progenitor cells. Because G-CSF and SCF are available for clinical use, these findings suggest a new therapeutic strategy for stroke.

Administration of hematopoietic cytokines increases the expression of anti-inflammatory cytokine (IL-10) mRNA in the subacute phase after stroke.

We investigated the effect of the subcutaneous administration of hematopoietic cytokines, granulocyte colony-stimulating factor (G-CSF)+stem cell factor (SCF), on mRNA expression of tissue cytokines in the acute or subacute phase after focal ischemia in male C57 BL/6J mice. The expression of IL-10 mRNA was elevated at 4-14 days after occlusion when cytokines were given in the acute phase (days 1-10). The expression of IL-10 mRNA was markedly elevated at 14 days after occlusion, then remained high until 28 days when cytokines were given in the subacute phase (days 11-20). However, there were no significant changes in IL-6, TGF-beta1, TNF, G-CSF, SCF and iNOS expression following either acute- or subacute-phase treatment. Further, hematopoietic cytokine treatment in the subacute phase, but not in the acute phase, reduced ED1-positive microglia/macrophages in the infarcted brain. Our recent study showed that the subacute-phase treatment is effective for functional recovery, enhancing generation of neuronal cells from both bone-marrow-derived and neural stem/progenitor cells. Taken together, these results suggest that cytokine treatment in the subacute phase may provide a favorable microenvironment for neurogenesis after ischemic stroke through the up-regulation of IL-10.

A novel inhibitor of advanced glycation and endoplasmic reticulum stress reduces infarct volume in rat focal cerebral ischemia.

We have developed a novel, non-toxic inhibitor of advanced glycation and oxidative stress, TM2002, devoid of effect on blood pressure. In transient focal ischemia, TM2002 significantly decreased infarct volume compared with vehicle (79.5+/-18.7 vs. 183.3+/-22.9 mm3, p<0.01). In permanent focal ischemia, TM2002 (2.79, 5.58, and 11.16 mg/kg twice a day) dose-dependently reduced infarct volume (242.1+/-32.3, 201.3+/-15.1, and 171.3+/-15.2 mm3, respectively), and improved neurological deficits. Reduction of infarct volume is demonstrable, provided that TM2002 was administered within 1.5 h after the occlusion. To unravel TM2002's mechanism of action, we examined its in vitro effect on endoplasmic reticulum (ER) stress, using aortic smooth muscle cells isolated from ORP 150(+/-) mice and F9 Herp null mutated cells. Cell death induced by ER stress (tunicamycin or hypoxia) was dose-dependently prevented by TM2002. In vivo immunohistochemical study demonstrated a significant reduction of ORP- and TUNEL-positive apoptotic cells, especially in the penumbra. Inhibition of advanced glycation and oxidative stress was confirmed by a significantly reduced number of cells positive for advanced glycation end products and heme oxygenase-1. TM2002 reduced the levels of protein carbonyl formation in ischemic caudate. The efficacy of TM2002 is equivalent to that of a known neuroprotective agent, NXY-059. In conclusion, TM2002 significantly ameliorates ischemic cerebral damage through reduction of ER stress, advanced glycation, and oxidative stress, independently of blood pressure lowering.