Treatment of risk factors to prevent stroke

Low molecular weight fucoidan alleviates cerebrovascular damage by promoting angiogenesis in type 2 diabetes mice

Diabetes leading to brain glucose metabolism disorders and cerebrovascular complications. Fucoidan is a kind of sulfated polysaccharides which found in brown algae, has multiply bioactivities and considered to be a promising therapeutic agent. Despite the increasing amount of evidence suggesting the diabetes protective role of fucoidans, the effect of fucoidan on brain abnormalities in type 2 diabetes mellitus patients remains unclear. In this study a low molecular weight fucoidan (LMWF) was obtained from Saccharina japonica and its effect on the cerebrovascular damage in db/db mice was investigated. Results were shown after LMWF treatment, the degree of cerebrovascular damage, the number of apoptotic neuronal cells and the inflammation were all decreased in db/db mice. Moreover, LMWF could up-regulates CD34 and VEGFA expression in db/db mice brain, and the subintestinal vessel angiogenesis in zebrafish was also promoted by LMWF. Moreover, the lumen formation of HUVEC endothelial cells was rescued by LMWF which was destroyed in high glucose treated endothelial cells. Further study found, LMWF alleviates vascular injury by up-regulating the expression level of phosphorylated PI3K and phosphorylated AKT. Our study indicates that LMWF has the potential to develop a cerebrovascular protection agent for type 2 diabetes patients.

A Nanomule Peptide Carrier Delivers siRNA Across the Intact Blood-Brain Barrier to Attenuate Ischemic Stroke

The blood-brain barrier (BBB) hinders the distribution of therapeutics intended for treatment of neuroinflammation (NI) of the central nervous system. A twelve-amino acid peptide that transcytoses the BBB, termed MTfp, was chemically conjugated to siRNA to create a novel peptide-oligonucleotide conjugate (POC), directed to downregulate NOX4, a gene thought responsible for oxidative stress in ischemic stroke. The MTfp-NOX4 POC has the ability to cross the intact BBB and knockdown NOX4 expression in the brain. Following induction of ischemic stroke, animals pretreated with the POC exhibited significantly smaller infarcts; accompanied by increased protection against neurological deterioration and improved recovery. The data demonstrates that the MTfp can act as a nanomule to facilitate BBB transcytosis of siRNAs; where the NOX-4 specific siRNA moiety can elicit effective therapeutic knockdown of a gene responsible for oxidative stress in the central nervous system. This study is the first to conclusively demonstrate both siRNA-carrier delivery and therapeutic efficacy in any CNS disease model where the BBB remains intact and thus offers new avenues for potential treatments of oxidative stress underlying neuroinflammation in a variety of neuropathologies that are currently refractory to existing therapies.

Estrogen preconditioning: A promising strategy to reduce inflammation in the ischemic brain

During the premenopausal phase of a woman's life, estrogen naturally protects against ischemic brain damage and its debilitating consequence of cognitive decline. However, the decline in estrogen at menopause exponentially increases a women's risk for cerebral ischemia and its severity. Supplementation of estrogen during menopause is the most logical solution to abate this increased risk for cerebral ischemia; however, continuous therapy has proven to be contraindicative. Studies from our laboratory over the past decade have shown that a single bolus or long-term periodic 17β-estradiol treatment(s) two days prior to ischemia mimics ischemic preconditioning-conferred protection of the brain in ovariectomized or reproductively senescent female rats. These studies also demonstrated that 17β-estradiol-induced preconditioning (EPC) requires estrogen receptor (ER)-subtype beta (ER-β) activation. ER-β is expressed throughout the brain, including in the hippocampus, which plays a key role in learning and memory. Because periodic activation of ER-β mitigates post-ischemic cognitive decline in ovariectomized female rats, it can be surmised that EPC has the potential to reduce post-ischemic damage and cognitive decline in females. Estrogens are key anti-inflammatory agents; therefore this review discusses the effects of EPC on the inflammasome. Furthermore, as we now clearly know, the brain acts differently in males and females. Indeed, neurodegenerative diseases, including cerebral ischemia, and pharmacological drugs affect males and females in different ways. Thus, inasmuch as the National Institutes of Health and the Stroke Treatment Academic Industry Roundtable (STAIR) consortium mandate inclusion of female experimental animals, this review also discusses the need to close the gap in our knowledge in future studies of EPC in female animal models of cerebral ischemia.

[Gender differences in stroke risk factors]

Currently, there are a lot of studies on gender-related risk factors for stroke. However, contradictory data and the lack of a common view on the problem of gender-based approach to stroke prevention determine the importance of this problem. The most significant sex-non-specific stroke risk factors are hypertension, cardiac conditions, including atrial fibrillation, smoking, glucose and lipid metabolism disorders, excessive alcohol consumption, overweight, low physical activity and sedentary lifestyle, emotional stress. However, the incidence and significance of each stroke risk factor in women are different compared with men, due to women's reproductive status. Hypertension, atrial fibrillation, diabetes mellitus, abdominal obesity, migraine with aura, emotional stress and depression are more common risk factors in women compared to men. The stroke risk factors unique to women are the timing of age at menarche, pregnancy, gestational diabetes mellitus, preeclampsia, hormonal status disturbances, the use of combined oral contraceptives and hormone replacement therapy.

Regional differences in the temporal evolution of stroke: a population-based study of Brazil according to sex in individuals aged 15-49 years between 1997 and 2012

Objective

The present study analyzed the temporal trend of stroke mortality according to sex in individuals aged 15–49 years in the different regions of Brazil between 1997 and 2012.

Results

There was progressive reduction in mortality rate due to stroke in Brazil. The reduction trend was the same for both sexes, although mortality remained slightly higher among men. There was a difference in mortality rates according to the administrative region of the country.

Electronic supplementary material

The online version of this article (10.1186/s13104-018-3439-x) contains supplementary material, which is available to authorized users.

Nicotine Alters Estrogen Receptor-Beta-Regulated Inflammasome Activity and Exacerbates Ischemic Brain Damage in Female Rats

Smoking is a preventable risk factor for stroke and smoking-derived nicotine exacerbates post-ischemic damage via inhibition of estrogen receptor beta (ER-β) signaling in the brain of female rats. ER-β regulates inflammasome activation in the brain. Therefore, we hypothesized that chronic nicotine exposure activates the inflammasome in the brain, thus exacerbating ischemic brain damage in female rats. To test this hypothesis, adult female Sprague-Dawley rats (6–7 months old) were exposed to nicotine (4.5 mg/kg/day) or saline for 16 days. Subsequently, brain tissue was collected for immunoblot analysis. In addition, another set of rats underwent transient middle cerebral artery occlusion (tMCAO; 90 min) with or without nicotine exposure. One month after tMCAO, histopathological analysis revealed a significant increase in infarct volume in the nicotine-treated group (64.24 ± 7.3 mm³; mean ± SEM; n = 6) compared to the saline-treated group (37.12 ± 7.37 mm³; n = 7, p < 0.05). Immunoblot analysis indicated that nicotine increased cortical protein levels of caspase-1, apoptosis-associated speck-like protein containing a CARD (ASC) and pro-inflammatory cytokines interleukin (IL)-1β by 88% (p < 0.05), 48% (p < 0.05) and 149% (p < 0.05), respectively, when compared to the saline-treated group. Next, using an in vitro model of ischemia in organotypic slice cultures, we tested the hypothesis that inhibition of nicotine-induced inflammasome activation improves post-ischemic neuronal survival. Accordingly, slices were exposed to nicotine (100 ng/mL; 14–16 days) or saline, followed by treatment with the inflammasome inhibitor isoliquiritigenin (ILG; 24 h) prior to oxygen-glucose deprivation (OGD; 45 min). Quantification of neuronal death demonstrated that inflammasome inhibition significantly decreased nicotine-induced ischemic neuronal death. Overall, this study shows that chronic nicotine exposure exacerbates ischemic brain damage via activation of the inflammasome in the brain of female rats.

[Lipid-lowering therapy in the elderly : Who profits from which target values?]

Lowering low-density lipoprotein (LDL) cholesterol levels has been proven to reduce the incidence of cardiovascular and cerebrovascular events and mortality. So far recommendations have not provided information as to a meaningful duration of cholesterol-lowering therapy and were largely guided by economic constraints and limited therapeutic options. In light of the decline in the price of statins, the essential therapeutic agent and the increased efficacy of therapeutic options, treatment can nowadays be geared to target values that can be expected to have an optimal effect even in old age. The most favorable level of LDL-cholesterol for primary prevention is around and below 100 mg/dl, provided continuous adherence to these low levels from adolescence onwards. With later onset of cholesterol reduction the existence of initial atheromatous deposits must be expected. Therefore, with age and the manifestation of other risk factors the optimal treatment targets increasingly converge to those for which experience has been gained from secondary prevention. Both measurements of the effect of cholesterol lowering on the volume of atheromatous plaques and of the incidence of vascular events indicate a target for LDL-cholesterol well below 70 mg/dl and in the range 50-60 mg/dl. At the onset of cholesterol lowering in advanced age, a smaller effect has to be expected but due to the increasing incidence rate of vascular events a higher number of events may be avoided; thus, the efficiency does not necessarily decrease; however, long-term studies indicate that earlier cholesterol lowering provides an advantage for more than a decade, in terms of preventing vascular disease, which tends to increase. Therefore, optimal cardiovascular prevention involves moderate measures to maintain the LDL-cholesterol below 100 mg/dl lifelong from childhood on.

Comparison of lipid profiles and inflammation in pre- and post-menopausal women with cerebral infarction and the role of atorvastatin in such populations

Background

The risks of atherosclerotic cardiovascular and cerebrovascular diseases in women rapidly increase with age in post-menopausal women. We aimed to investigate the lipid profiles in peri-menopausal women with cerebral infarction and to explore the effects of atorvastatin intervention.

Methods

We collected women aged 40-60 with cerebral infarction between January 2013 and December 2016. Atorvastatin was applied for 6 months in all included patients. Blood lipid profiles, serum pro-inflammation cytokines, intracranial plaque and NIH stroke scale (NIHSS) scores were evaluated before and after atorvastatin treatment.

Results

Totally 210 patients were included. Before atorvastatin treatment, post-menopausal patients had significantly higher levels of triglyceride, cholesterol, low-density lipoprotein and a reduced level of high-density lipoprotein than those in pre-menopausal patients. Blood levels of pro-inflammatory cytokines including interleukin (IL)-1, IL-6 and tumor necrosis factor-α were higher in post-menopausal patients, who had larger intracranial plaques than pre-menopausal patients. Consistently, post-menopausal patients had higher NIHSS scores than pre-menopausal ones. Atorvastatin reduced NIHSS scores and improved dyslipidemia in patients and eliminated the differences of these parameters between pre- and post-menopausal patients.

Conclusions

Post-menopausal patients were severer than pre-menopausal patients in terms of dyslipidemia, systemic inflammation and NIHSS scores. Atorvastatin may be beneficial for women with cerebral infarction.

Acute Ischemic Stroke: Current Status and Future Directions

The evolving knowledge on stroke in conjunction with advances in the field of imaging, treatment approaches using recombinant tissue plasminogen activator (rtPA) or thrombectomy devices in recanalization, and efficient emergency stroke workflow processes have opened new frontiers in managing patients with an acute ischemic stroke. These frontiers have been reformed and overcome in overcoming the decades-long watch and wait approach towards patients with ischemic stroke. In this article, we focus on the current strategies for managing ischemic stroke and conclude by providing a brief overview of anticipating developments that can transform future stroke treatments.

Alterations in white matter volume and integrity in obesity and type 2 diabetes

Type 2 diabetes mellitus (T2DM) is characterized by obesity, hyperglycemia and insulin resistance. Both T2DM and obesity are associated with cerebral complications, including an increased risk of cognitive impairment and dementia, however the underlying mechanisms are largely unknown. In the current study, we aimed to determine the relative contributions of obesity and the presence of T2DM to altered white matter structure. We used diffusion tensor imaging (DTI) and voxel-based morphometry (VBM) to measure white matter integrity and volume in obese T2DM patients without micro- or macrovascular complications, age- gender- and BMI-matched normoglycemic obese subjects and age- and gender-matched normoglycemic lean subjects. We found that obese T2DM patients compared with lean subjects had lower axial diffusivity (in the right corticospinal tract, right inferior fronto-occipital tract, right superior longitudinal fasciculus and right forceps major) and reduced white matter volume (in the right inferior parietal lobe and the left external capsule region). In normoglycemic obese compared with lean subjects axial diffusivity as well as white matter volume tended to be reduced, whereas there were no significant differences between normoglycemic obese subjects and T2DM patients. Decreased white matter integrity and volume were univariately related to higher age, being male, higher BMI, HbA1C and fasting glucose and insulin levels. However, multivariate analyses demonstrated that only BMI was independently related to white matter integrity, and age, gender and BMI to white matter volume loss. Our data indicate that obese T2DM patients have reduced white matter integrity and volume, but that this is largely explained by BMI, rather than T2DM per se.

Effect of eprosartan-based antihypertensive therapy on coronary heart disease risk assessed by Framingham methodology in Canadian patients with diabetes: results of the POWER survey

OBJECTIVE

As part of the Physicians' Observational Work on Patient Education According to their Vascular Risk (POWER) survey, we used Framingham methodology to examine the effect of an eprosartan-based regimen on total coronary heart disease (CHD) risk in diabetic patients recruited in Canada.

METHODS

Patients with new or uncontrolled hypertension (sitting systolic blood pressure [SBP] >140 mmHg with diastolic blood pressure <110 mmHg) were identified at 335 Canadian primary care practices. Initial treatment consisted of eprosartan 600 mg/day, which was later supplemented with other antihypertensives as required. Outcomes included change in SBP at 6 months (primary objective) and absolute change in the Framingham 10-year CHD risk score (secondary objective).

RESULTS

We identified an intention-to-treat diabetes population of 195 patients. Most diabetic patients were prescribed two or more antihypertensive drugs throughout the survey. Mean reductions in SBP and diastolic blood pressure were 20.8±14.8 mmHg and 9.5±10.7 mmHg, respectively. The overall absolute mean 10-year CHD risk, calculated using Framingham formulae, declined by 2.9±3.5 points (n=49). Average baseline risk was higher in men than women (14.8±8.6 versus 5.6±1.8 points); men also had a larger average risk reduction (4.2±4.3 versus 1.5±1.3 points). The extent of absolute risk reduction also increased with increasing age (trend not statistically significant).

CONCLUSION

Eprosartan-based therapy substantially reduced arterial blood pressure in our subset of diabetic patients; while there was a slight reduction in Framingham risk, there are indications from our data that both blood pressure control and the wider management of CHD risk in diabetic patients remains suboptimal in Canadian primary care.

Long-term outcome of catheter ablation in atrial fibrillation patients with coexistent metabolic syndrome and obstructive sleep apnea: impact of repeat procedures versus lifestyle changes

INTRODUCTION

Metabolic syndrome (MS) and obstructive sleep apnea (OSA) are well-known independent risk factors for atrial fibrillation (AF) recurrence. This study evaluated ablation outcome in AF patients with coexistent MS and OSA and influence of lifestyle modifications (LSM) on arrhythmia recurrence.

METHODS AND RESULTS

We included 1,257 AF patients undergoing first catheter ablation (30% paroxysmal AF). Patients having MS + OSA were classified into Group 1 (n = 126; 64 ± 8 years; 76% male). Group 2 (n = 1,131; 62 ± 11 years; 72% male) included those with either MS (n = 431) or OSA (n = 112; no CPAP users) or neither of these comorbidities (n = 588). Patients experiencing recurrence after first procedure were divided into 2 subgroups; those having sporadic events (frequency < 2 months) remained on previously ineffective antiarrhythmic drugs (AAD) and aggressive LSM, while those with persistent arrhythmia (incessant or ≥2 months) underwent repeat ablation. After 34 ± 8 months of first procedure, 66 (52%) in Group 1 and 386 (34%) in Group 2 had recurrence (P < 0.001). Recurrence rate in only-MS, only-OSA, and without MS/OSA groups were 40%, 38%, and 29%, respectively. Patients with MS + OSA experienced substantially higher recurrence compared to those with lone MS or OSA (52% vs. 40% vs. 38%; P = 0.036). Of the 452 patients having recurrence, 250 underwent redo-ablation and 194 remained on AAD and LSM. At 20 ± 6 months, 76% of the redo group remained arrhythmia-free off AAD whereas 74% of the LSM group were free from recurrence (P = 0.71), 33% of which were off AAD.

CONCLUSIONS

MS and OSA have additive negative effect on arrhythmia recurrence following single procedure. Repeat ablation or compliant LSM increase freedom from recurrent AF.

Cerebral white matter integrity and resting-state functional connectivity in middle-aged patients with type 2 diabetes

Early detection of brain abnormalities at the preclinical stage can be useful for developing preventive interventions to abate cognitive decline. We examined whether middle-aged type 2 diabetic patients show reduced white matter integrity in fiber tracts important for cognition and whether this abnormality is related to preestablished altered resting-state functional connectivity in the default mode network (DMN). Diabetic and nondiabetic participants underwent diffusion tensor imaging, functional magnetic resonance imaging, and cognitive assessment. Multiple diffusion measures were calculated using streamline tractography, and correlations with DMN functional connectivity were determined. Diabetic patients showed lower fractional anisotropy (FA) (a measure of white matter integrity) in the cingulum bundle and uncinate fasciculus. Control subjects showed stronger functional connectivity than patients between the posterior cingulate and both left fusiform and medial frontal gyri. FA of the cingulum bundle was correlated with functional connectivity between the posterior cingulate and medial frontal gyrus for combined groups. Thus, middle-aged patients with type 2 diabetes show white matter abnormalities that correlate with disrupted functional connectivity in the DMN, suggesting that common mechanisms may underlie structural and functional connectivity. Detecting brain abnormalities in middle age enables implementation of therapies to slow progression of neuropathology.

Impact of a physician-supervised exercise-nutrition program with testosterone substitution in partial androgen-deficient middle-aged obese men

Background

Partial androgen deficiency syndrome in the aging male is associated with signs of aging such as a development of abdominal obesity, sexual dysfunction, increase body fat, weight gain and the development of cardiac disease.

Objective

We assessed the outcome of a commercially available physician supervised nutrition and exercise program with concomitant testosterone replacement therapy in middle age obese men with partial androgen deficiency in order to reduce cardiac risks factors.

Methods

Fifty-six self referred men without diabetes mellitus, hypertension, or cardiovascular disease (ages 52.3 ± 7.8 years) were randomly selected from a large cohort. Baseline weight, body fat composition, fasting glucose, hemoglobin A1c and fasting lipid levels, as well as free and total testosterone levels were assessed. All patients were assessed and followed 6–18 months after initiation of the program. The program consisted of a low glycemic load balanced nutrition diet, a recommended structured daily exercise program of 30–60 minutes, as well as once to twice weekly intramuscular testosterone injections (113.0 ± 27.8 mg).

Results

At follow up, weight was reduced from 233.9 ± 30.0 pounds (lbs) to 221.3 ± 25.1 lbs (P < 0.001), BMI was reduced from 33.2 ± 3.3 kg/m² to 31.3 ± 2.8 kg/m² (P < 0.0001). Total body fat was 27.1% ± 5.2% vs. 34.3% ± 5.7% at baseline (P < 0.0001). Fasting glucose was reduced from 95.3 ± 14.4 mg/dL to 87.5 ± 12.6 mg/dL (P < 0.0001). Total cholesterol was reduced from 195.4 ± 33.0 mg/dL to 172.7 ± 35.0 mg/dL (P < 0.005). No clinically significant adverse events were recorded.

Conclusions

Testosterone replacement therapy in middle aged obese men with partial androgen deficiency appeared safe and might have promoted the effects of a weight reduction diet and daily exercise program as long as an adequate physician supervision and follow up was granted. The combination therapy significantly reduced coronary risk factors such as glucose intolerance and hyperlipidemia.

Metabolic syndrome in ischemic stroke: A case control study

INTRODUCTION

The metabolic syndrome has known as an independent risk factor of stroke. The occurrence of this syndrome is due to genetic factors and lifestyle. This study was performed on the frequency of metabolic syndrome prevalence in ischemic stroke patients compare to control.

MATERIALS AND METHODS

one hundred ischemic stroke patients and 100 controls (with the same age and sex) were evaluated for this study.

RESULT

62% of patient and 34% of controls had metabolic syndrome criteria according to National Cholesterol Education Program (NCEP) {OR: 3.2; 95% CI (1.9-9.7), P=0.001} Prevalence of metabolic syndrome in women was more than men (52% vs. 44%) {OR: 0.72; 95% CI (0.4, 1.3)}. Beside of metabolic syndrome, prevalence of metabolic syndrome components was significantly higher in stroke patients compare to controls.

CONCLUSION

metabolic syndrome prevalence are more common in stroke patients compare to controls, but it should be noticed that the controls are in a risk of future stroke so they need special treatment to prevent it.