Isolation of endothelial progenitor cells from cord blood and induction of differentiation by ex vivo expansion

Endothelial progenitor cells (EPCs) have been reported to possess the capacity to colonize vascular grafts and hold promise for therapeutic neovascularization. However, limited quantities of EPCs have been the major factor impeding effective research on vasculoangiogenesis. In this study, cytokine and culture conditions necessary for the provision of large quantities of endothelial cells (ECs) were investigated. Cord blood was collected from 18 normal full-term deliveries and CD34+ cells were isolated by MACS system (Miltenyi Biotech, Bergish-Gladbach, Germany). To evaluate the effect of cytokines, CD34+ cells were cultured with various cytokine combinations, such as stem cell factor (SCF), flt3-ligand (FL), and thrombopoietin (TPO) with vascular endothelial growth factor (VEGF), interleukin-1 beta , fibroblast growth factor-basic (FGF-b) as basic cytokines. The quantities of non-adherent and adherent cells were the greatest with SCF, FL and TPO. The addition of TPO to all other cytokines significantly increased the number of non-adherent and adherent cells (p< 0.05, Wilcoxon rank sum test). After four weeks of culture, adherent cells expressed endothelial specific markers such as KDR, CD31 and CD62E. Typical morphology of ECs was observed during culture, such as cord-like structure and cobblestone appearance, suggesting that the adherent cells were consistent with ECs. In this study, the experimental conditions that optimize the production of ECs for therapeutic neovascularization were described. And it was possibly suggested that TPO plays a major role in differentiation from EPCs to ECs.     

Aphasia following striatocapsular infarction may be explained by concomitant small cortical infarct on diffusion-weighted imaging

BACKGROUND: The underlying mechanism of aphasia following striatocapsular infarction (SCI) remains controversial. We hypothesized that aphasia resulting from SCI might be associated with concomitant cortical lesions, which can be demonstrated by diffusion-weighted imaging (DWI). METHODS: We analyzed 24 patients with left SCI who underwent DWI and MR angiography within 2 days after the onset. Aphasia was assessed by the modified Korean version of the Boston Diagnostic Aphasia Examination test. RESULTS: DWI showed the presence of additional ischemic lesions involving the cortical areas in 13 of 24 SCI patients (54%). Ten patients (42%) showed aphasia. All 10 patients with aphasia had cortical lesions in addition to SCI (p = 0.0002), whereas 21% (3/14) of the nonaphasic patients had additional cortical lesions. Conventional MRI did not reveal the presence of corresponding acute cortical lesions in any of the aphasic patients. There was no difference between the patients with and without aphasia in terms of their stroke etiology. CONCLUSIONS: Our data suggest that aphasia due to SCI in the acute stage may be attributed to direct cortical injury, whose presence can be demonstrated by DWI, even though it might be invisible on conventional imaging.     

Diagnostic and prognostic value of early MR Imaging vessel signs in hyperacute stroke patients imaged <3 hours and treated with recombinant tissue plasminogen activator

BACKGROUND AND PURPOSE: Analogous to the CT hyperattenuated vessel sign (HMCAS), MR imaging may show hypo- or hyperintense vessels in acute ischemic stroke (AIS) patients. We assessed the diagnostic and prognostic strength of early MR imaging vessel signs in AIS patients treated with intravenous thrombolysis (IVT) within 3 hours of the onset of symptoms. METHODS: We studied AIS patients both treated with IVT and stroke MR imaged within 3 hours of the onset of symptoms and at 2 hours and 24 hours after treatment. We assessed the presence or absence of early vessel signs (hyperintense fluid-attenuated inversion recovery sign [FLAIR HVS]; gradient-echo susceptibility vessel sign [GRE SVS]) compared with a combined MR angiography/perfusion-weighted imaging reference and their strength for predicting clinical outcome (favorable vs. poor, independent vs. dependent, or dead, death), recanalization (by clot composition and flow), and hemorrhage in uni- and multivariate analysis. RESULTS: Fifty-six patients (age range, 76 years +/- 13 years; median National Institutes of Health stroke scale score [NIHSSS], 11) met the inclusion criteria. Forty-four patients (78.6%) had a vessel occlusion at baseline; 22 of them (50%) recanalized. Nineteen patients (33.9%) suffered some form of intracranial hemorrhage (ICH), 24 patients (42.9%) had an independent outcome, 18 patients (32.1%) a favorable outcome, and 14 patients died. Compared with our combined reference for vessel status PWI/MRA, the sensitivities of CT HMCAS, FLAIR HVS, and GRE SVS were 40%, 66%, and 34%, respectively, and improved during the hours that followed. Localization was accurately reflected by FLAIR HVS but not by GRE SVS. Only NIHSSS and age were independent predictors for recanalization and all clinical outcomes in multiple logistic regression analysis. CONCLUSION: Although early vessel signs can be helpful in the diagnosis of intravascular disease, they do not independently predict recanalization, ICH, or any of the three clinical outcomes in a multivariate logistic regression model. Thrombus composition as reflected by signal intensity characteristics on GRE and FLAIR does not predict the therapeutic effect of IVT.     

Diffusion-weighted MRI and 99mTc-HMPAO SPECT in delayed relapsing type of carbon monoxide poisoning: evidence of delayed cytotoxic edema

BACKGROUND: Carbon monoxide (CO) is a common cause of poisoning, and its sequelae include a progressive (25%) and a delayed relapsing form (75%). We report the diffusion-weighted MRI (DWI) findings in the delayed relapsing form of CO poisoning and characterize the types of edema. METHODS: From November 1, 2000 to June 1, 2003, 5 consecutive patients (2 men, 3 women, range of age: 54-67 years), who had the delayed relapsing type of CO poisoning, underwent DWI, conventional MRI, MR angiography and SPECT. CO poisoning was diagnosed by the presence of a typical clinical history, an abnormally increased level of serum carboxyhemoglobin and MRI findings. Apparent diffusion coefficient (ADC) values were measured in all of the abnormal lesions with visual inspection of DWI and T(2)-weighted echo-planar imaging. RESULTS: DWI showed high signal intensities in bilateral periventricular white matter, in the splenium of the corpus callosum, in internal capsules, and brainstem showing moderately decreased ADC values. In the globus pallidus, the ADC values were rather increased with low signal intensities on DWI. Brain SPECT showed decreased perfusion in bilateral white matter and some parts of the cerebral cortex, which correlated well with the DWI findings. CONCLUSIONS: We suggest that prominent, symmetric restricted diffusion can occur in periventricular white matter, brainstem, and corpus callosum after the delayed relapsing type of CO poisoning. Delayed cytotoxic edema can occur in this setting, which provides a new guidance for the pathogenesis of CO poisoning and the differential diagnosis of white matter diseases.     

Early recurrent ischemic lesions on diffusion-weighted imaging in symptomatic intracranial atherosclerosis

BACKGROUND: Prior observations have shown that early recurrent ischemic lesions (ERILs) on diffusion-weighted imaging occur frequently within the first week after an index stroke. OBJECTIVE: To investigate differential patterns of ERILs among stroke subtypes, particularly intracranial large-artery atherosclerosis (IC-LAA). DESIGN: Retrospective study. SETTING: Tertiary university hospital. PATIENTS: We included 133 patients who experienced an acute ischemic stroke and who underwent initial diffusion-weighted imaging within 24 hours and subsequent diffusion-weighted imaging within 7 days after onset, and whose stroke subtype was IC-LAA, extracranial LAA (EC-LAA), or cardioembolism (CE). MAIN OUTCOME MEASURE: Early recurrent ischemic lesions were defined as new ischemic lesions on follow-up diffusion-weighted imaging, separate from the index stroke lesion. RESULTS: Early recurrent ischemic lesions were observed in the following proportions: 50.9% (28/55) in the IC-LAA group, 47.4% (9/19) in the EC-LAA group, and 44.1% (26/59) in the CE group. Early recurrent ischemic lesions in the IC-LAA group had the following characteristics: (1) they occurred mostly (27 [96.4%] of 28) in the pial area of the same vascular territory as the index stroke; (2) they were more frequently observed in a higher grade of stenosis than in milder stenosis (P<.001), whereas ERILs in the EC-LAA group were not related to the degree of stenosis; (3) they were not associated with subsequent recanalization, whereas ERILs in the CE group were mostly associated with subsequent recanalization (P<.001); and (4) they were more closely associated with clinical recurrence than in the EC-LAA or CE group (P=.02). CONCLUSION: Early recurrent ischemic lesions in the IC-LAA group are relatively frequent and have different patterns than in the EC-LAA or CE group.