The worldwide problem of stroke

Serum Irisin Levels and Its Relationship with Spasticity Severity in Chronic Stroke Patients

Objective Irisin is a myokine released from muscles by exercise and it has been shown to be a prognostic indicator in acute stroke patients. However, irisin's relationship with the chronic phase of stroke and spasticity has not been studied yet. We aimed to determine the serum level of irisin to examine its relationship with the functional status and severity of spasticity in patients with chronic stroke, and to compare these with healthy controls.

Materials and Methods A total of 70 (35 chronic stroke and 35 control patients) patients were included in the study. The blood serum irisin levels of the patients and the controls were evaluated using enzyme-linked immunosorbent assay method, their functional status was evaluated with the modified Rankin scale (mRS), and spasticity severity using the modified Ashworth scale (MAS).

Results The mean serum irisin levels of the stroke and the control groups were 6.20 ± 2.2 and 5.45 ± 2.3, respectively, and there was no statistically significant difference (p > 0.05). No significant correlation was found between the serum level of irisin and the severity of spasticity and functional status, assessed by the mRS in stroke patients.

Conclusion These results showed that irisin levels in chronic stroke patients were similar to controls, and there was no relationship between the severity of spasticity and functional status and irisin level.

Platycarya strobilacea leaf extract protects mice brain with focal cerebral ischemia by antioxidative property

The leaf extract of Platycarya strobilacea (PSL) has long been recognized as possessing various health-promoting activities. However, information on its possible protective effects against ischemic stroke is currently lacking. Here, using a mouse model of focal cerebral ischemia (fCI), we studied the protective potential of an oral supplement of PSL. Mice were randomly divided into four groups: SO, a group subjected to a sham-operation; VEH, pretreated with distilled water and subjected to middle cerebral artery occlusion and reperfusion (MCAO/R); PSL-L and PSL-H, pretreated with low (20 mg/kg) and high (100 mg/kg) doses of PSL, respectively, and subjected to the MCAO/R procedure. PSL was administered via an oral route daily for 8 days prior to surgery. We then measured the infarct volumes and sensorimotor deficits and studied the underlying antioxidant mechanisms by quantifying apoptosis, reactive oxygen species (ROS) generation, oxidative damages, and antioxidant enzymes in the ischemic cortex. The results showed a marked attenuation in infarct volume and sensorimotor deficits in both the PSL-L and PSL-H groups when compared with VEH. The terminal deoxynucleotidyl transferase dUTP nick end labeling and the immunohistochemical detection of the cleaved caspase-3 revealed that PSL could reduce cellular apoptosis in the ischemic lesion in a dose-dependent manner. The dihydroethidium-fluorescence, 4-hydroxynonenal, and 8-hydroxyl-2'-deoxyguanosine immunoreactivities in the ischemic lesion were markedly attenuated in the PSL-L group compared with the VEH group, indicating that PSL could attenuate ROS generation and the associated oxidative damage in the ischemic cortex. Finally, western blot results indicated that PSL can upregulate levels of heme oxygenase-1 (HO-1), an antioxidant enzyme, in the lesion area. Together, these results suggest that PSL can exert protective effects against fCI, and the mechanism may involve HO-1 upregulation.

The C825T GNB3 polymorphism, independent of blood pressure, predicts cerebrovascular risk at a population level

BACKGROUND

The role of C825T polymorphism of the candidate GNB3 gene in predicting cerebrovascular outcome has been poorly explored in longitudinal setting at a population level.

METHODS

In an epidemiological setting, 1,678 men and women from general population were genotyped for C825T polymorphism of GNB3 gene and follow-up for 10 years to detect nonfatal and fatal cerebrovascular events (CE). Established cerebrovascular risk factors were used to adjust the multivariate Cox analysis for confounders.

RESULTS

Seventy-three nonfatal and 30 fatal CE were recorded. Incidence of CE was higher in TT than in C-carriers (fatal: 2.6 vs. 1.7%, P < 0.03; nonfatal: 7.8 vs. 3.9%, P < 0.03; fatal recurrences: 1.6 vs. 0.6%, P < 0.03). In Cox analysis, the TT genotype predicted nonfatal (hazard ratio 1.99, 95% confidence interval 1.05-3.79, P = 0.03), fatal (2.91, 1.05-8.12, P = 0.04), and fatal recurrent CE (6.82, 1.50-31.1, P = 0.02) also after adjustment for age, gender, systolic and diastolic blood pressure, body adiposity, atherogenetic blood lipids, serum uric acid, diabetes, calories, caffeine and ethanol intake, and coronary events at baseline. Further adjustment for historical CE made the association between TT genotype and incident fatal CE nonsignificant (hazard ratio 2.72, 95% confidence interval 0.96-7.22, P = 0.06).

CONCLUSIONS

The TT genotype of GNB3 gene predicts incident CE independent of blood pressure and other established risk factors at a population level. Further studies are needed to clarify the nature and pathways of this association.

Acute ischemic stroke and transient ischemic attack in the very old - risk factor profile and stroke subtype between patients older than 80 years and patients aged less than 80 years

Old age groups have different risk profile and stroke features compared to younger groups. Our aim was to examine the risk factor profile and stroke subtype in patients older than 80 years with ischemic stroke. Data of 535 patients with ischemic stroke or transient ischemic attack (TIA) were prospectively recorded. Cardiovascular risk factors and stroke subtype in individuals aged 80 years or older were compared with patients under 80. Of 535 patients a total of 179 were over 80 years (33.5%). The mean age was 84.4 +/- 4.4 years (61.8%; 111 women). The most common risk factors included hypertension (82.7%) and hyperlipidemia (40.2%). Lacunar stroke was the most frequent subtype of stroke (41.7%). When the groups were compared, we observed the following risk factors more frequently in the group older than 80: female patients (P = <0.001), hypertension (OR = 1.62), atrial fibrillation (OR = 2.64); whereas diabetes (OR = 0.54), hyperlipidemia (OR = 0.57), smoking (OR = 0.17) and obesity (OR = 0.58) were more frequent in the group younger than 80. In the old group we found a high incidence of ischemic stroke in women. We also found a higher frequency of hypertension and atrial fibrillation. The available and future epidemiological data will provide a better knowledge about the effect of typical risk factors in old people.

Segmental left ventricular wall motion abnormalities are associated with lacunar ischemic stroke

OBJECTIVE

The aim of this study was to determine whether segmental left ventricular wall motion abnormalities (SLVWMA) are a potential cause of ischemic stroke.

METHODS

Demographics, cardiovascular risk factors and echocardiographic parameters of patients with ischemic stroke (with and without SLVWMA) were collected and compared with those of patients who had SLVWMA but without history of ischemic stroke.

RESULTS

Two hundred and fifty nine patients with ischemic stroke were identified: 187 patients without SLVWMA, and 72 with SLVWMA. The cardiac group consisted of 79 patients. Compared with the stroke patients with SLVWMA, stroke patients without SLVWMA were slightly but significantly younger (59 versus 63 years of age). Furthermore, the number of risk factors in stroke patients without SLVWMA was significantly lower compared with stroke patients with SLVWMA (2.7 versus 3.7). There was no difference in age or gender between stroke patients with SLVWMA and the cardiac patients. However, the number of risk factors was significantly higher in the cardiac patients compared with stroke patients with SLVWMA (4.4 versus 3.7). The ejection fraction was normal in both groups of stroke patients but significantly lower in the cardiac patients (37%). Significantly more lacunar ischemic strokes were observed in stroke patients with SLVWMA than in those without SLVWMA (76% versus 68%).

CONCLUSION

Our data indicate that in ischemic stroke patients with multiple cardiovascular risk factors and SLVWMA a higher frequency of lacunar strokes can be found. The latter could be a marker of small-vessel disease and/or be a potential contributing factor, perhaps through a mechanism of cardiac microembolism, in the development of lacunar ischemic stroke. The mechanisms of the association between SLVWMA and lacunar ischemic stroke remain however unclear.

Ethnic Variations in Risk Factor Profile, Pattern and Recurrence of Non-Cardioembolic Ischemic Stroke

BACKGROUND

Ischemic stroke is influenced by ethnic and geographical variations. The aim of this study was to identify the risk factor profiles, subtypes and recurrence of non-cardioembolic ischemic stroke for the two largest subpopulations, the Arab and South Asians, at the only stroke-admitting hospital in Qatar.

METHODS

Data on stroke patients admitted to Hamad Medical Corporation from January through December 2001 were reviewed in January 2005. Only patients with non-cardioembolic ischemic stroke and complete work-up were included.

RESULTS

A total of 303 patients with ischemic non-cardioembolic stroke fit the entry criteria. Sixty seven percent of the overall patient population (sex ratio 2:6, M/F) was of Arab origin, and 32% were South Asians. Hypertension was the most commonly encountered risk factor followed by dyslipidemia, diabetes mellitus, and obesity. Significant differences between the Arab and South Asian subgroup of patients were observed with respect to number of risk factors and occurrence of obesity and diabetes. Carotid artery stenotic lesions, ventricular wall motion abnormalities and stroke recurrence were observed with a higher frequency in the Arab subgroup of patients compared with the South Asians. The majority of strokes were lacunar hemispheric strokes (68%), followed by lacunar brainstem strokes (15%) and large-vessel hemispheric infarctions (10%). Patients with a previous history of stroke had a higher frequency of carotid artery stenosis (p = 0.05) and risk of stroke recurrence (p = 0.04).

CONCLUSIONS

Unlike in other studies originating from the Arabian Gulf, lacunar stroke is the most common subtype of non-cardioembolic ischemic stroke in both the Arabs and South Asians in Qatar. Significant ethnic differences in age of occurrence, risk factor profile, and cardiovascular variables were observed.

Delayed treatment with monoclonal antibody IN-1 1 week after stroke results in recovery of function and corticorubral plasticity in adult rats

Neuronal death due to ischemic stroke results in permanent deficits in sensory, language, and motor functions. The growth-restrictive environment of the adult central nervous system (CNS) is an obstacle to functional recovery after stroke and other CNS injuries. In this regard, Nogo-A is a potent neurite growth-inhibitory protein known to restrict neuronal plasticity in adults. Previously, we have found that treatment with monoclonal antibody (mAb) IN-1 to neutralize Nogo-A immediately after stroke enhanced motor cortico-efferent plasticity and recovery of skilled forelimb function in rats. However, immediate treatment for stroke is often not clinically feasible. Thus, the present study was undertaken to determine whether cortico-efferent plasticity and functional recovery would occur if treatment with mAb IN-1 was delayed 1 week after stroke. Adult rats were trained on a forelimb-reaching task, and the middle cerebral artery was occluded to induce focal cerebral ischemia to the forelimb sensorimotor cortex. After 1 week, animals received mAb IN-1 treatment, control antibody, or no treatment, and were tested for 9 more weeks. To assess cortico-efferent plasticity, the sensorimotor cortex opposite the stroke lesion was injected with an anterograde neuroanatomical tracer. Behavioral analysis demonstrated a recovery of skilled forelimb function, and anatomical studies revealed neuroplasticity at the level of the red nucleus in animals treated with mAb IN-1, thus demonstrating the efficacy of this treatment even if administered 1 week after stroke.

Long-lasting functional disabilities in middle-aged rats with small cerebral infarcts

Recommendations from experts and recently established guidelines on how to improve the face and predictive validity of animal models of stroke have stressed the importance of using older animals and long-term behavioral-functional endpoints rather than relying almost exclusively on acute measures of infarct volume in young animals. The objective of the present study was to determine whether we could produce occlusions in older rats with an acceptable mortality rate and then detect reliable, long-lasting functional deficits. A reversible intraluminar suture middle cerebral artery occlusion (MCAO) procedure was used to produce small infarcts in middle-aged rats. This resulted in an acceptable mortality rate, and robust disabilities were detected in functional assays, although the degree of total tissue loss measured 90 d after MCAO was quite modest. Infarcted animals were functionally impaired relative to sham control animals even 90 d after the occlusions, and when animals were subgrouped based on amount of tissue loss, MCAO animals with only 4% tissue loss exhibited enduring neurological-behavioral impairments relative to sham-operated controls, and the functional impairments in the group with the largest infarcts (20% tissue loss) were more severe than the functional impairments in the rats with 4% tissue loss. These results suggest that this model, using reversible MCAO to produce small infarcts and long-lasting functional-behavioral deficits in older rats, may represent an advance in the relatively higher-throughput modeling of stroke and its recovery in rodents and may be useful in the development and characterization of future stroke therapies.

Differences in vascular risk factors between etiological subtypes of ischemic stroke: importance of population-based studies

BACKGROUND

To understand the mechanisms of stroke and to target prevention, we need to know how risk factors differ between etiological subtypes. Hospital-based studies may be biased because not all stroke patients are admitted. If risk factors differ between patients who are admitted and those who are not, then case-control studies will be biased. If the likelihood of admission also depends on stroke subtype, then case-case comparisons may also be biased.

METHODS

We compared risk factors and ischemic stroke subtypes (TOAST classification) in hospitalized and nonhospitalized patients in 2 population-based stroke incidence studies: the Oxford Vascular Study (OXVASC) and Oxfordshire Community Stroke Project (OCSP). We also performed a meta-analysis of risk factor-stroke subtype associations with other published population-based studies.

RESULTS

In OXVASC and OCSP, stroke subtypes differed between hospitalized (293 of 647) and nonhospitalized patients (P<0.0001), with more cardioembolic strokes (odds ratio [OR], 1.8; 95% CI, 1.3 to 2.6) and fewer lacunar strokes (OR, 0.4; 95% CI, 0.3 to 0.7). Premorbid blood pressure and cholesterol were higher in hospitalized patients (both P<0.0001). Risk factor-stroke subtype associations in hospitalized patients were consequently biased (P=0.001). Meta-analysis of data from all patients in OXVASC, OCSP, and 2 other studies demonstrated consistent risk factor-stroke subtype associations. However, contrary to previous hospital-based studies, there was only a weak (OR, 1.4; 95% CI, 1.1 to 1.8) and inconsistent (P(heterogeneity)=0.01) association between small-vessel stroke and hypertension and no association with diabetes (OR, 1.0; 95% CI, 0.7 to 1.3).

CONCLUSIONS

Prevalences of risk factors and stroke subtypes differ between hospitalized and nonhospitalized patients with ischemic stroke, which may bias hospital-based risk factor studies. Meta-analysis of population-based studies suggests that vascular risk factors differ between stroke subtypes.

Predictors of stroke mortality in elderly people from the general population. The CArdiovascular STudy in the ELderly

Stroke occurs particularly frequently in elderly people and, being more often disabling than fatal, entails a high social burden. The predictors of stroke mortality have been identified in 3282 subjects aged > or = 65 years, taking part in the CArdiovascular STudy in the ELderly (CASTEL), a population-based study performed in Northeast Italy. Historical and clinical data, blood tests and 14-year fatal events were recorded. Continuous items were divided into quintiles and, for each quintile, adjusted relative risk (RR) with 95% confidence intervals [CI] was derived from multivariate Cox analysis. Age, historical stroke (RR: 5.2; 95% CI: 3.18-8.6) and coronary artery disease (RR: 1.38; CI: 1.18-2.1), atrial fibrillation (RR: 2.40; CI: 1.42-4.0), arterial hypertension (RR: 1.33; CI: 1.15-1.76), systolic blood pressure > or = 163 mmHg (RR: 1.84; CI: 1.20-2.59), pulse pressure > or = 74 mmHg (RR: 1.50; CI: 1.13-2.40), cigarette smoking (RR: 1.60; CI: 1.03-2.47), electrocardiographic left ventricular hypertrophy (RR: 1.72; CI: 1.10-2.61), impaired glucose tolerance (IGT, RR: 1.83; CI: 1.10-3.0), uric acid (UA) > 0.38 mmol/l (RR: 1.61; CI: 1.14-2.10), serum potassium > or = 5 mEq/l (RR: 1.70; CI: 1.24-2.50) and serum sodium < or = 139 mEql/l (RR: 1.34; 1.10-2.10) increased the risk of stroke. In the CASTEL, stroke was the first cardiovascular cause of death. Some independent predictors usually unrelated to stroke mortality (namely pulse pressure, pre-diabetic IGT, UA and blood electrolytes disorders) have been identified.

Stroke epidemiology: a review of population-based studies of incidence, prevalence, and case-fatality in the late 20th century

This overview of population-based studies of incidence, prevalence, mortality, and case-fatality of stroke was based on studies from 1990. Incidence (first stroke in an individual's lifetime) and prevalence were computed by age, sex, and stroke type. Age-standardised incidence and prevalence with the corresponding 95% CI were plotted for each study to facilitate comparisons. The review shows that the burden of stroke is high and is likely to increase in future decades as a result of demographic and epidemiological transitions in populations. The main features of stroke epidemiology include modest geographical variation in incidence, prevalence, and case-fatality among the--predominantly white--populations studied so far, and a stabilisation or reversal in the declining secular trends in the pre-1990s rates, especially in older people. However, further research that uses the best possible methods to study the incidence, risk factors, and outcome of stroke are urgently needed in other populations of the world, especially in less developed countries where the risk of stroke is high, lifestyles are changing rapidly, and population restructuring is occurring.

The emerging role of induced hypothermia in the management of acute stroke

Current treatment of acute stroke remains unsatisfactory. This review presents experimental and clinical data which suggest that mild induced hypothermia could be a potent and practicable neuroprotective treatment of acute ischaemic stroke and intracerebral haemorrhage. Hypothermia, if proven to be safe, effective and widely practicable in patients with acute stroke, could have an enormous positive impact on reducing the burden of stroke worldwide. Critical issues that will need to be considered in a well designed randomised controlled trial of induced hypothermia in acute stroke patients are discussed.

Stroke incidence and mortality correlated to stroke risk factors in the WHO MONICA Project. An ecological study of 18 populations

BACKGROUND

The aim of the present study was to determine the extent to which the variation in conventional risk factors contributed to the variation in stroke incidence among these populations.

METHODS

Within the WHO MONICA Project, stroke has been recorded in 18 populations in 11 countries. In population surveys, risk factors for cardiovascular diseases have been examined in the age group 35 to 64 years. Over a 3-year period, 12,224 acute strokes were registered in men and women within the same age range.

RESULTS

The highest stroke attack rates were found in Novosibirsk in Siberia, Russia, and Finland, with a more than three-fold higher incidence than in Friuli, Italy. The mean diastolic blood pressure among the populations differed by 15 mm Hg between Novosibirsk (highest) and Denmark (lowest). In multiple regression analyses, the presence of conventional cardiovascular risk factors (smoking and elevated blood pressure) explained 21% of the variation in stroke incidence among the population in men and 42% in women. In Finland, in China, and in men in Lithuania, the stroke incidence rates were higher than expected from the population risk factor levels.

CONCLUSION

Prevalence of smoking and elevated blood pressure explain a substantial proportion of the variation of stroke attack rates between populations. However, other risk factors for stroke that were not measured in the present study also contribute considerably to interpopulation differences in stroke rates.

Perspectives of stroke in persons living in Seoul, South Korea. A survey of 1000 subjects

BACKGROUND AND PURPOSE

The aim of the present study was to investigate the perspectives of stroke in persons who live in Seoul, South Korea, a country which is unique in that the social and political status of traditional (herbal) medicine is equal to that of western (modern) medicine.

METHODS

We randomly selected 1000 persons living in Seoul, South Korea, and performed open-ended telephone interviews regarding stroke risk factors, symptoms, and the choice of treatment for stroke. We also asked whether the subjects would prefer to visit western-medicine doctors or traditional-medicine doctors if they developed stroke.

RESULTS

Twenty-nine percent of the interviewees responded correctly that the most important risk factor for stroke is hypertension. However, other major factors, such as cigarette smoking, diabetes mellitus, and heart disease, were greatly underappreciated, while less important risk factors such as hyperlipidemia/obesity, stress, and exposure to coldness were overappreciated. Also, although 65% of the subjects correctly identified paresis as the most important symptom of stroke, tremor was indicated incorrectly as an important symptom of stroke. Regarding the choice of treatment, only 46% responded that visiting a hospital is the most important method of treatment, whereas a significant percentage of the subjects responded that they would prefer herbal medicine and other traditional methods of treatment. Generally, the older and less educated the subjects, the more they prefer to depend on traditional medicine.

CONCLUSIONS

These data show that perspectives of stroke are heavily influenced by the presence of traditional medicine in Korea, especially in older and less educated persons. This perspective significantly deviates from the scientific concept regarding the etiology, symptoms, and treatment of stroke. Current science-based health education is urgently needed in this country.