Effects of microplasmin on recovery in a rat embolic stroke model

OBJECTIVES: The purpose of the present study was to examine the effects of microplasmin on behavioral performance and infarct volume after middle cerebral artery occlusion (MCAO) in rats. Some experiments support that microplasmin may have neuroprotective and thrombolytic properties. METHODS: Eighty rats underwent surgery and were embolized in the right carotid territory with a fibrin-rich embolus and randomly assigned into three groups: 5 mg/kg microplasmin, 10 mg/kg microplasmin or saline (control). Groups treated with microplasmin received 50% bolus injection 10 minutes after embolization and 50% continuous infusion during the following hour. Animals from all groups were trained to obtain high baseline scores in Montoya's staircase test before embolization and were retested during 7-14 days after surgery. RESULTS: When pre-maturely dead animals were excluded, no differences were observed among groups regarding infarct volumes. Furthermore, mortality was significantly lower in Group 1 than in Group 2 (p<0.05) and when performances were evaluated 7-14 days after surgery, Group 1 was significantly better than Group 2 concerning fine motor performance (p<0.05) and also achieved more normal bodyweight (p<0.05). DISCUSSION: Among surviving animals, 5 mg/kg microplasmin treatment had no effect compared to saline-treated control animals; 5 mg/kg microplasmin reduced mortality and improved both behavioral rehabilitation and bodyweight compared to 10 mg/kg microplasmin treatment, while saline-treated animals did not differ from animals treated with 10 mg/kg microplasmin. Overall, these results indicate a potential beneficial effect of 5 mg/kg microplasmin treatment, while 10 mg/kg may worsen outcomes.     

Effect of consecutive application of paired associative stimulation on motor recovery in a rat stroke model: a preliminary study

This study investigated the changes in motor evoked potential (MEP) amplitude and motor behavior index when paired associative stimulation (PAS), a conjoint stimulation of a peripheral nerve and the motor cortex, was applied in a rat stroke model. The PAS was applied to 19 rats and sham stimulation was applied to 15 rats. One part of PAS consisted of peripheral electrical stimulation of the soleus muscle and the other part was transcranial magnetic stimulation of the motor cortex. The stimulation was repeated for 30 min with a frequency of 0.05 Hz. Five sessions of PAS were applied over 5 consecutive days. The motor behavior index was higher in the PAS group than in the sham stimulation group at 7 d after ischemic brain injury. There was no lasting difference between the PAS animals and the sham stimulation group in MEP amplitude although MEP amplitude was increased immediately after PAS. MEP amplitude can be increased by the PAS paradigm in rats as well as in humans and PAS has potential therapeutic value for motor recovery after brain injury.     

Effect of age on autonomic and cardiac responses in a rat stroke model.

The cardiovascular system and its responses change with increasing age. This has seldom been considered in experimental models of stroke, although most strokes occur in the elderly. We studied 57 male Wistar rats in three age groups: 47 to 70 days old (juvenile), 110 to 152 days old (young adult), and 186 to 245 days old (mature adult), each group being subdivided into experimental and sham operation groups. All rats underwent occlusion or sham occlusion of the left middle cerebral artery and monitoring of the mean arterial blood pressure, heart rate, sympathetic nerve activity, plasma catecholamine levels, and electrocardiogram. Eight of the 12 rats in the oldest group died within 6 hours of the middle cerebral artery occlusion; of these, the youngest was 186 days old. The mature adult rats that died before completion of the experiment showed the highest level of sympathetic nerve activity and the only significant increase in the QT interval of the electrocardiogram. Following middle cerebral artery occlusion, sympathetic nerve activity increased in the young adult rats but most strikingly in the mature adult rats that died before the end of the 6-hour experiments. Plasma norepinephrine levels were significantly elevated at 4 and 6 hours after middle cerebral artery occlusion in the oldest group and only at 6 hours in the juvenile rats. The results of this study are consistent with impaired sympathetic and cardiovascular regulation in the mature adult rat. High sympathetic activity may represent one mechanism leading to fatal cardiac arrhythmias. Age-related impairment of sympathetic regulation may contribute to the higher mortality seen among elderly patients with stroke.     

系统化康复治疗对脑卒中偏瘫患者功能恢复的影响

目的探讨系统化康复治疗对脑卒中偏瘫患者肢体运动功能和日常生活活动(ADL)能力的影响。方法 84例脑卒中患者随机分为康复组和对照组,分别于治疗前及治疗后60 d对两组患者采用简化Fugl-Meyer量表(FMA)和Barthel指数(BI)来评定患者运动功能及ADL能力。结果治疗前,两组患者的FMA评分和BI评分差异均无显著统计学意义(P>0.05);治疗后,两组患者的FMA评分和BI评分与治疗前比较,均有明显改善(P<0.05)。结论系统化康复治疗对脑卒中偏瘫患者的肢体运动功能和ADL能力的恢复具有显著促进作用。     

Effect of socioeconomic status on functional and motor recovery after stroke: a European multicentre study

Background

Previous studies have shown an inverse gradient in socioeconomic status for disability after stroke. However, no distinction has been made between the period in the stroke rehabilitation unit (SRU) and the period after discharge. The purpose of this study was to examine the impact of education and equivalent income on motor and functional recovery for both periods.

Methods

419 consecutive patients were recruited from six SRUs across Europe. The Barthel Index (BI) and Rivermead Motor Assessment (RMA) were measured on admission, at discharge and 6 months after stroke. Ordinal logistic regression models were used, adjusting for case mix. Cumulative odds ratios (OR) were calculated to measure differences in recovery between educational levels and income groups with adjustments for case mix.

Results

Patients with a low educational level were less likely to improve on the BI (OR 0.53; 95% CI 0.32 to 0.87) and the RMA arm during inpatient stay (OR 0.54; 95% CI 0.31 to 0.94). For this period, no differences in recovery were found between income groups. After discharge, patients with a low equivalent income were less likely to improve on all three sections of the RMA: gross function (OR 0.20; 95% CI 0.06 to 0.66), leg and trunk (OR 0.22; 95% CI 0.09 to 0.55) and arm (OR 0.30; 95% CI 0.10 to 0.87). No differences were found for education.

Conclusions

During inpatient rehabilitation, educational level was a determinant of recovery, while after discharge, equivalent income played an important role. This study suggests that it is important to develop a better understanding of how socioeconomic factors affect the recovery of stroke patients.Socioeconomic health inequalities have been studied for a long time but the publication of the Black Report¹ in the UK provoked the attention of policy makers for the existence of important health inequalities² and resulted in an increased awareness of these issues in health care in general.³ At the end of the 20th century, some authors even considered socioeconomic health disparities as the most important public health issue.⁴Stroke is no exception to the general findings on health inequalities. The incidence of fatal and non‐fatal strokes shows an inverse gradient over socioeconomic groups. In an unselected population based sample, Thrift and colleagues⁵ found that the incidence rate of both stroke types was higher in disadvantaged areas. These disparities remain in the post‐acute period. The proportion of patients who are dependent or dead at 6 months after stroke varies between groups of different socioeconomic status (SES). Patients with a lower SES are at greater risk for stroke morbidity and stroke mortality compared with higher SES groups.^6,7 However, these associations were not confirmed by other studies.^8,9 In a recent review by Cox and colleagues¹⁰ it was concluded that the association between SES and morbidity and mortality is well known but that the reasons behind this association are far from clear.The socioeconomic gradient in disability after stroke is also observed in the chronic phase. Patients with lower SES experienced more disabilities up to 3 years post‐stroke compared with the group of patients with a higher SES.¹¹ It remains unclear whether these differences are the result of differences in stroke severity at onset or whether they become more prominent over time.Comparison of results between studies may be difficult because of the different methods used to define SES. Several indicators are used to determine SES (eg, education, income). Various models are used explaining health inequalities, and education and income reflect different dimensions of socioeconomic inequalities in health.¹² The behavioural/cultural explanation is perhaps the most widely used.¹³ This model refers to the more systematic unhealthy behaviours and lifestyle in lower socioeconomic groups, in part related to differences in knowledge or awareness of risks. In this model, distinction between SES groups is often based on educational attainment.¹³ The materialist model tries to explain differences in health between SES groups by material factors (eg, housing, work conditions), and income is mainly used as an indicator for material stratification.¹⁴Apart from the choice of SES indicator, differences in how the selected indicator is measured may hamper comparison between studies and make general conclusions more difficult. For example, the measurement of an indicator can be based on an individual level or at a more aggregated area level. Although individual based indicators are preferred,¹⁵ the availability of data is probably an underestimated factor in how indicators are measured.As most functional recovery is expected to take place in the first 5 months after stroke,¹⁶ stroke rehabilitation units (SRUs) may play an important role in minimising discrepancies between socioeconomic groups. However, the influence of SES on recovery during inpatient stay has not been studied. Moreover, illness trajectories are not often considered in the comparison of functional recovery between socioeconomic groups.¹⁷ To the best of our knowledge, no distinction has been made between recovery during stay in an inpatient SRU and after discharge for different SES groups. Therefore, the aim of this study was to assess the association of education and equivalent income with functional and motor recovery for these two periods.     

Effect of levetiracetam on testosterone levels in male patients

We sought to determine whether the testosterone increase found with levetiracetam exposure in animal studies also occurs in patients. Adult male patients were evaluated for reproductive hormone levels before and 1 month after levetiracetam therapy. Eight subjects met inclusion/exclusion criteria (mean age 46 years, range 29-75 years). Total testosterone prior to starting levetiracetam ranged from 206-787 ng/dl [mean 445, standard deviation (SD) 227]. The mean total testosterone after levetiracetam therapy increased to 592 ng/dl (range 216-981, SD 297), an increase of 16% (p = 0.036). The free testosterone increased from a mean of 64 pg/ml (range 36-115, SD 30) to a mean of 76 pg/ml (range 35-155, SD 44), an increase of 19% (p = 0.080). The magnitude of change in testosterone levels correlated with the initial testosterone level (p = 0.038, r = 0.734). These results suggest that levetiracetam increases testosterone levels and that an initial testosterone level may predict the magnitude of increase.     

Post-stroke depression and functional recovery in a population-based stroke register. The Finnstroke study

Post-stroke depression and functional outcome were examined in a population-based stroke register active in four different districts (total population, 134 804) in Finland. Five hundred and ninety four first time strokes were registered. Beck's depression inventory (BDI), with ten as the cutoff point for depression, was applied to 321 of 423 survivors after three months and to 311 of 390 survivors after 12 months. Functional outcome was measured with the Barthel Index (BI) and the Rankin Scale (RS). One hundred and fifty one of 321 (47.0%) and 147 of 311 (47.3%) patients were depressed after three and 12 months, respectively. Depression at three months was associated with poor functional outcome at the one-year follow-up (P = 0.001 for the BI and the RS). On the other hand, poor functional outcome at three months was associated with depression after one year (P = 0.004 and 0.002 for the BI and the RS, respectively). Patients who were depressed at three months were more often in institutional care between three and 12 months later than non-depressed patients (P = 0.005). Post-stroke depression is associated with poor functional recovery of patients. If depression were diagnosed and treated early, it might help patients to recover more completely and/or faster, which could save community healthcare resources by avoiding or shortening the time of institutional care or reducing the need for home care.     

Correlation between functional and electrophysiological recovery in acute ischemic stroke.

BACKGROUND AND PURPOSE: There is still controversy about the prognostic value of motor evoked potentials (MEPs) in the assessment of hemiplegia. The aims of this study are to determine the relationship between functional and electrophysiological recovery and thus the value of MEP as a prognostic indicator of clinical outcome in acute ischemic stroke. METHODS: Seventeen healthy subjects and 38 stroke patients were included in this study. Functional recovery was assessed with the Modified Canadian Neurological Scale (MCNS), the Barthel Activities of Daily Living Index (BI), and the Rankin scale. Transcranial magnetic stimulation was used to determine the change in central motor conduction time (CMCT). Stroke outcome was assessed at the end of 2 weeks. One-way ANOVA with post hoc comparisons using the Scheffé procedure as well as t tests were used to assess the significance of the results in this study. RESULTS: Unpaired t test showed significantly higher mean scores of the MCNS (2P=0.001), BI (2P=0.002), and Rankin scale (P<0.001) at day 14 in the group of patients with recordable MEP at day 1. A better clinical improvement with a higher mean score of the MCNS (2P<0.001), BI (2P<0.001), and the Rankin scale (2P<0.001) was also observed in the patients in whom the CMCT improved. CONCLUSIONS: These data show that there is a close relationship between clinical and electrophysiological improvement and that MEP is a useful prognostic indicator of clinical outcome.     

Serial MRI, functional recovery, and long-term infarct maturation in a non-human primate model of stroke

We have examined the effects of permanent middle cerebral artery occlusion (pMCAO) in marmoset monkeys over 5 months, using behavioural and magnetic resonance imaging (MRI) techniques. Three marmosets were trained on behavioural tests before pMCAO. Shortly after surgery, these marmosets were scanned with T2-weighted (T2W) and diffusion-weighted (DW) MRI. Three, 10 and 20 weeks after surgery, these marmosets were re-tested on the behavioural tasks and had further MRI sessions to monitor lesion development. This was followed by histological analysis. All these marmosets had a persistent contralesional motor deficit and a spatial neglect which resolved over the 20 weeks of testing. Percentage infarct volume assessed by MRI on the day of surgery and at 20 weeks matched the percentage infarct volume measured histologically at 20 weeks. However, the apparent infarct size at 3 weeks was considerably less than that measured by histological analysis or that measured at the other MRI time points. Additional histological analysis of the brains of two further marmosets removed 3 weeks after pMCAO found considerable infiltration by lipid filled macrophages into the ischaemic zone which may have caused an MRI "fogging" effect leading to an apparent reduction in infarct volume.     

Effect of hypothermia and delayed thrombolysis in a rat embolic stroke model

Effect of hypothermia on cerebral infarcts was studied in rats embolized in the right carotid territory. Thirty-four served as normothermic controls receiving saline infusion only. In 16 rats hypothermia of 32°C was induced by cooling with a fan, followed by embolization. The rats were kept hypothermic for the following 3 h before body temperature was raised to 37°C. In 26 rats, treatment with human recombinant tissue plasminogen activator (20 mg/kg i.v. during 45 min), started 2 h after embolization. Finally, 14 rats were treated similarly with hypothermia for 3 h followed by additional rt-PA treatment starting after 2 h. Thrombolytic therapy reduced median infarct volume from 19.5% of affected hemisphere among controls to 4.6% (p = 0.006) in the treated group. Three hours of hypothermia reduced infarct volume to 1.6% (p = 0.0007). Additional rt-PA could not demonstrate further improvement in this experimental setting.     

Human marrow stromal cell therapy for stroke in rat: neurotrophins and functional recovery

OBJECTIVE: To test the effect of i.v.-injected human bone marrow stromal cells (hMSC) on neurologic functional deficits after stroke in rats. METHODS: Rats were subjected to transient middle cerebral artery occlusion and IV injected with 3 x 10(6) hMSC 1 day after stroke. Functional outcome was measured before and 1, 7, and 14 days after stroke. Mixed lymphocyte reaction and the development of cytotoxic T lymphocytes measured the immune rejection of hMSC. A monoclonal antibody specific to human cellular nuclei (mAb1281) was used to identify hMSC and to measure neural phenotype. ELISA analyzed neurotrophin levels in cerebral tissue from hMSC-treated or nontreated rats. Bromodeoxyuridine injections were used to identify newly formed cells. RESULTS: Significant recovery of function was found in rats treated with hMSC at 14 days compared with control rats with ischemia. Few (1 to 5%) hMSC expressed proteins phenotypic of brain parenchymal cells. Brain-derived neurotrophic factor and nerve growth factor significantly increased, and apoptotic cells significantly decreased in the ischemic boundary zone; significantly more bromodeoxyuridine-reactive cells were detected in the subventricular zone of the ischemic hemisphere of rats treated with hMSC. hMSC induced proliferation of lymphocytes without the induction of cytotoxic T lymphocytes. CONCLUSION: Neurologic benefit resulting from hMSC treatment of stroke in rats may derive from the increase of growth factors in the ischemic tissue, the reduction of apoptosis in the penumbral zone of the lesion, and the proliferation of endogenous cells in the subventricular zone.     

The effect of duration of muscle denervation on functional recovery in the rat model

The effect of long-term denervation on neuromuscular recovery was studied in a rat hind limb model. The posterior tibial nerve was transected and repaired immediately or after denervation periods of 2 weeks, or 1, 3, 6, 9, or 12 months. Six months following reconstruction excellent axonal regeneration was seen across all nerve repairs irrespective of periods of denervation. However, there was a precipitous and profound decrease in the recovery of both muscle mass and integrated motor function if the reconstruction was delayed for longer than 1 month. Rather than a progressive change proportional to the length of the denervation period, significant, more discrete changes occurred sometime after 1 month of denervation that precluded a full recovery of muscle mass. Integrated motor function quantified using walking track analysis was impaired even after immediate nerve repair. © 1997 John Wiley & Sons, Inc. Muscle Nerve 20: 858–866, 1997     

Effects of spontaneous recanalization on functional and electrophysiological recovery in acute ischemic stroke.

BACKGROUND AND PURPOSE: Transcranial Doppler ultrasound (TCD) studies have shown that spontaneous recanalization results in a better clinical improvement after the onset of stroke. However, its effect on electrophysiological recovery is still unknown. The aim of this study was to determine the effects of spontaneous recanalization on the change in central motor conduction time (CMCT) in acute ischemic stroke. METHODS: Seventeen healthy subjects and 38 consecutive patients with a first acute ischemic stroke involving the middle cerebral artery territory were included. TCD was used to detect spontaneous recanalization. Transcranial magnetic stimulation was used to determine the change in CMCT on days 1 and 14. Improvement of the CMCT at day 14 was indicated if it decreased in comparison with previous data recorded at day 1 or when a nonrecordable motor response at day 1 reappeared at day 14. No CMCT improvement was indicated when there was no recordable motor response at day 1 and day 14 or the CMCT at day 14 worsened, becoming absent or more delayed. The Pearson chi(2) test was used to assess the statistical significance of the results in this study. RESULTS: Spontaneous recanalization was observed in 62% of the patients: 24% before 24 hours and 38% after this period. No recanalization was observed in 14 patients. The CMCT improved in 87% of the patients who had recanalized before 24 hours and 62% in the recanalized after 24 hours group (P=0.005). In contrast, CMCT improved in only 17% of the patients in the non-recanalized group CONCLUSIONS: These data show that spontaneous recanalization results in a better recovery of the central motor pathway leading to a better CMCT improvement in acute ischemic stroke.     

清麴酱激酶的溶栓活性可减轻栓塞性脑梗死后脑损伤

Cheonggukjang is a soybean paste made by fermenting whole cooked soybean with Bacillus subtilis. Cheonggukjang contains a fibrinolytic enzyme that may have clinical applications in removing blood clots. In this study, we use the term “cheonggukjang kinase” (CGK) to refer to this fibrinolytic enzyme. We used fibrin clot lysis and platelet-rich clot lysis assays to clarify the mechanisms by which CGK exerts thrombolytic effects, and, specifically, whether it acts more like a plasminogen activator or like plasmin. Additionally, we examined the thrombolytic effects of CGK in a rat model of cerebral embolic stroke produced by middle cerebral artery occlusion (MCAO) with respect to infarct volume and behavioral performance. In both the fibrin clot lysis and platelet-rich clot lysis assays, the thrombolytic activity was highest in CGK that had been cultured for 40 h. Furthermore, T50%, the time needed to decompose half the clot, did not differ in the presence or absence of plasminogen, indicating that CGK is a plasmin-like protein, not a plasminogen activator. In the rat model of cerebral embolic stroke, clots were no longer visible in rats that received an intravenous infusion of CGK (1 U plasmin-like activity/100 μg CGK/kg) 1 h after MCAO. CGK-treated groups showed a significant dose-dependent reduction in infarct volume. Treatment with CGK also improved functional recovery, as assessed by neurological deficit scores. Reduction of infarct volume and improvement in functional recovery after CGK treatment (1 U plasmin-like activity/100 μg CGK/kg) was greater than after treatment with recombinant tissue plasminogen activator (r-tPA; 10 mg/kg). These data suggest that CGK is an effective agent for reducing infarct volume and improving functional recovery following ischemic brain injury. Moreover, CGK may be a more efficacious clot-dissolving agent than r-tPA. CGK has a number of potential clinical applications in the treatment of stroke.     

Imaging neurovascular function and functional recovery after stroke in the rat striatum using forepaw stimulation

Negative functional magnetic resonance imaging (fMRI) response in the striatum has been observed in several studies during peripheral sensory stimulation, but its relationship between local field potential (LFP) remains to be elucidated. We performed cerebral blood volume (CBV) fMRI and LFP recordings in normal rats during graded noxious forepaw stimulation at nine stimulus pulse widths. Albeit high LFP–CBV correlation was found in the ipsilateral and contralateral sensory cortices (r=0.89 and 0.95, respectively), the striatal CBV responses were neither positively, nor negatively correlated with LFP (r=0.04), demonstrating that the negative striatal CBV response is not originated from net regional inhibition. To further identify whether this negative CBV response can serve as a marker for striatal functional recovery, two groups of rats (n=5 each) underwent 20- and 45-minute middle cerebral artery occlusion (MCAO) were studied. No CBV response was found in the ipsilateral striatum in both groups immediately after stroke. Improved striatal CBV response was observed on day 28 in the 20-minute MCAO group compared with the 45-minute MCAO group (P<0.05). This study shows that fMRI signals could differ significantly from LFP and that the observed negative CBV response has potential to serve as a marker for striatal functional integrity in rats.     

Hypothalamic testosterone increase in the male rat at birth

In the male rat, a dramatic increase in serum testosterone occurs during the first 2 h of postnatal life. Since the hypothalamus is known to be an important site for sexual differentiation of the brain, this early testosterone surge was a good model to use to study the transfer of serum testosterone to the hypothalamus and cerebral cortex. Endogenous testosterone was measured by radioimmunoassay in the hypothalamus and the cerebral cortex of the foetus and newborn rats during the first 6 h following birth. In the male, hypothalamic testosterone increased between 0 h in utero and 2 h; in the males gonadectomized at 0 h in utero and killed at the age of 2 h, the testosterone surge was abolished, clearly indicating the testicular origin of this hormone in the neonate. The small testosterone increase in the cerebral cortex compared with that in the hypothalamus reflects a preferential uptake of this hormone by the hypothalamus of the newborn. In the female, hypothalamic testosterone slightly decreased between 0 h in utero and 6 h. These results are in agreement with the view that hypothalamic modifications form the basis for some behavioral and physiological changes attributed to the effect of perinatal hormonal stimulation.