Correlation of Peripheral Blood Inflammatory Indicators to Prognosis After Intravenous Thrombolysis in Acute Ischemic Stroke: A Retrospective Study

Purpose

According to many previous studies, neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR) and hypersensitive C-reactive protein (CRP) are commonly used as important indicators to assess the prognosis of intravenous thrombolysis in AIS patients. Based on this, we used two novel biomarkers C-NLR (CRP/neutrophil-to-lymphocyte ratio) and C-LMR (CRP×lymphocyte-to-monocyte ratio) to investigate their correlation with 90-day outcomes in AIS patients after intravenous thrombolysis.

Patients and Methods

A total of 204 AIS patients who received intravenous thrombolysis at the Stroke Center of Jiangsu Province Hospital of Chinese Medicine from January 2021 to December 2022 were retrospectively included. All patients were followed up 90 days after thrombolysis to assess their prognosis. Patients with a modified Rankin scale score (mRS) of 3-6 were included in the unfavorable outcome group, and those with a score of 0-2 were included in the favorable outcome group. Logistic regression analysis, receiver operating characteristic (ROC) curve, and Kaplan-Meier survival curve were used to investigate the association between C-NLR, C-LMR, and 90-day prognosis in AIS patients treated with early intravenous thrombolysis.

Results

C-NLR (OR=1.586, 95% CI=1.098~2.291, P=0.014) and C-LMR (OR=1.099, 95% CI=1.025~1.179, P=0.008) were independent risk factors for 90-day prognosis of AIS patients treated with early intravenous thrombolysis. The higher C-NLR and C-LMR were associated with unfavorable prognosis.

Conclusion

C-NLR and C-LMR can be used as biomarkers to predict prognosis of AIS patients treated with early intravenous thrombolysis.

Application of Induced Pluripotent Stem Cells in Moyamoya Disease: Progress and Promises

Moyamoya disease (MMD) is a chronic steno-occlusion cerebrovascular disease, accompanied by the formation of abnormal vascular network at the base of brain. The etiology of MMD is not fully clarified. Lack of pathological specimens hinders the research progress. Induced pluripotent stem cell (iPSC) derived from patients with outstanding differentiation potential and infinite proliferation ability could conquer the problem of insufficient sample. The technology of iPSC holds the promise of clarifying the underlying molecular mechanism in the development of MMD. In this review, we summarized latest progresses and difficulties in the research of mechanism, and detailed the application of iPSC in MMD, aiming to provide an outlook of iPSC in molecular mechanism and novel therapies of MMD.

Pathogeneses and Imaging Features of Cerebral White Matter Lesions of Vascular Origins

White matter lesion (WML), also known as white matter hyperintensities or leukoaraiosis, was first termed in 1986 to describe the hyperintense signals on T2-weighted imaging (T2WI) and fluid-attenuated inversion recovery (FLAIR) maps. Over the past decades, a growing body of pathophysiological findings regarding WMLs have been discovered and discussed. Currently, the generally accepted WML pathogeneses mainly include hypoxia-ischemia, endothelial dysfunction, blood-brain barrier disruption, and infiltration of inflammatory mediators or cytokines. However, none of them can explain the whole dynamics of WML formation. Herein, we primarily focus on the pathogeneses and neuroimaging features of vascular WMLs. To achieve this goal, we searched papers with any type published in PubMed from 1950 to 2020 and cross-referenced the keywords including “leukoencephalopathy”, “leukoaraiosis”, “white matter hyperintensity”, “white matter lesion”, “pathogenesis”, “pathology”, “pathophysiology”, and “neuroimaging”. Moreover, references of the selected articles were browsed and searched for additional pertinent articles. We believe this work will supply the robust references for clinicians to further understand the different WML patterns of varying vascular etiologies and thus make customized treatment.

The Influence of Demographics and Vascular Risk Factors on Glymphatic Function Measured by Diffusion Along Perivascular Space

Assessing glymphatic function using in-vivo imaging method is of great value for understanding its contribution to major brain diseases. In the present study, we aim to validate the association between a variety of risk factors and a potential index of glymphatic function—Diffusion Tensor Image Analysis Along the Perivascular Space (ALPS index). We enrolled 142 subjects from communities and performed multi-modality magnetic resonance imaging scans. The ALPS index was calculated from diffusion tensor imaging data, and its associations with demographic factors, vascular factors were investigated using regression analyses. We found that the ALPS index was negatively associated with age (β = −0.284, p < 0.001). Compared to males, females had significantly higher ALPS index (β = −0.243, p = 0.001). Hypertensive subjects had significantly lower ALPS index compared to non-hypertensive subjects (β = −0.189, p = 0.013). Furthermore, venous disruption could decrease ALPS index (β = −0.215, p = 0.003). In general, our results are in consistent with previous conceptions and results from animal studies about the pathophysiology of glymphatic dysfunction. Future studies utilizing this method should consider introducing the above-mentioned factors as important covariates.

CD34+ cells and endothelial progenitor cell subpopulations are associated with cerebral small vessel disease burden

Background: Endothelial dysfunction is considered to be involved in the pathogenesis of cerebral small vessel disease (CSVD). Endothelial progenitor cells are associated with endothelial dysfunction. The present study was designed to investigate the correlation between the populations of circulating CD34-positive cells and endothelial progenitor cells and CSVD burden. Methodology & results: A total of 364 patients with confirmed diagnosis of CSVD were included in this prospective study. Multiple ordinal logistic regression analyses showed that subjects with higher CSVD burden had significantly decreased circulating CD34⁺ cell level (odds ratio [OR], 0.42; p = 0.034) and significantly increased levels of circulating CD34⁺CD133⁺CD309⁺ and CD34⁺CD133⁺ cells (OR 1.07, p = 0.031; OR 1.03, p = 0.001, respectively), compared with patients with lower CSVD burden. Conclusion: The findings suggest that the levels of circulating CD34⁺ cells, CD34⁺CD133⁺CD309⁺ cells and CD34⁺CD133⁺ cells may be used as potential biomarkers to monitor the disease progression of CSVD.

Potential of Glucagon-Like Peptide 1 as a Regulator of Impaired Cholesterol Metabolism in the Brain

Cerebral vascular diseases are the most common high-mortality diseases worldwide. Their onset and development are associated with glycemic imbalance, genetic background, alteration of atherosclerotic factors, severe inflammation, and abnormal cholesterol metabolism. Recently, the gut-brain axis has been highlighted as the key to the solution for cerebral vessel dysfunction in view of cholesterol metabolism and systemic lipid circulation. In particular, glucagon-like peptide 1 (GLP-1) is a cardinal hormone that regulates blood vessel function and cholesterol homeostasis and acts as a critical messenger between the brain and gut. GLP-1 plays a systemic regulatory role in cholesterol homeostasis and blood vessel function in various organs through blood vessels. Even though GLP-1 has potential in the treatment and prevention of cerebral vascular diseases, the importance of and relation between GLP-1 and cerebral vascular diseases are not fully understood. Herein, we review recent findings on the functions of GLP-1 in cerebral blood vessels in association with cholesterol metabolism.

Chronic Insomnia Is Associated with Higher Circulating Interleukin-8 in Patients with Atherosclerotic Cerebral Small Vessel Disease

OBJECTIVE

Chronic inflammatory responses and leukocyte infiltration are classical pathological features of cerebral small vessel disease (CSVD). To date, limited evidence of a relationship between chronic insomnia and inflammatory responses in patients with CSVD has been uncovered. The purpose of the present study was to investigate the potential relationship between chronic insomnia and pro-inflammatory cytokine levels in patients with atherosclerotic CSVD (A-CSVD).

METHODS

In total, 76 A-CSVD patients with or without chronic insomnia (CI) confirmed using magnetic resonance (MR) were prospectively recruited. Overnight polysomnography (PSG) was performed and serum levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6, IL-17A, IL-8, and IL-12 assessed. Cytokine levels were compared between CSVD+CI (study group) and CSVD without CI (control group) patients, and the correlations between PSG parameters and cytokine levels were explored in all patients via multiple linear regression analyses.

RESULTS

The serum IL-8 level of the study group (12.3±4.4 pg/mL) was significantly higher than that of the control group (7.5±2.2 pg/mL; P<0.05). PSG measurements showed that patients in the study group had significantly higher sleep onset latency (SOL), arousal index (ArI) and wake after sleep onset (WASO) as well as lower total sleep time (TST), sleep efficiency (SE) and stage 3 NREM sleep (N-3) ratio, compared with the control group (P<0.05). Multiple linear regression analyses led to the identification of ArI (β=0.026, P<0.05) and TST (β=-0.054, P<0.05) as significant positive and negative predictors of the IL-8 level, respectively.

CONCLUSION

Chronic insomnia, in particular, sleep fragmentation and short sleep duration, may be involved in promotion of serum IL-8 expression in patients with atherosclerotic CSVD.

Influence of COVID-19 on Cerebrovascular Disease and its Possible Mechanism

The global spread of COVID-19 has caused a substantial societal burden and become a major global public health issue. The COVID-19 elderly population with hypertension, diabetes, cardiovascular, and cerebrovascular diseases are at risk. Mortality rates are highest in these individuals if infected with COVID-19. Although the lungs are the main organs involved in acute respiratory distress syndrome caused by COVID-19 infection, COVID-19 triggers inflammatory and immune mechanisms, inducing a "cytokine storm" that aggravates disease progression and may lead to death. Presently, effective drugs are lacking, although current studies have confirmed that drugs with therapeutic potential include redaciclovir, lopinavir/ritonavir combined with interferon-β, convalescent plasma, and monoclonal antibodies. Currently, the most reasonable and effective way to prevent COVID-19 is to control the source of infection, terminate routes of transmission, and protect susceptible populations. With the rise of COVID-19 in China and worldwide, further prevention, diagnosis, and treatment measures are a critical unmet need. Cerebrovascular disease has high incidence, disability rate, and fatality rate. COVID-19 patient outcomes may also be complicated with acute stroke. This paper summarizes the influence of COVID-19 on cerebrovascular disease and discusses possible pathophysiological mechanisms to provide new angles for the prevention and diagnosis of this disease.

Risk of Ischemic Stroke and Peripheral Arterial Disease in Heterozygous Familial Hypercholesterolemia: A Meta-Analysis

Heterozygous familial hypercholesterolemia (HeFH) is a common genetic disorder predisposing affected individuals to lifelong low-density lipoprotein cholesterol (LDL-C) elevation and coronary heart disease. However, whether HeFH increases the risk of peripheral arterial disease (PAD) and ischemic stroke is undetermined. We examined associations between HeFH and these outcomes in a comprehensive systematic review and meta-analysis. We searched MEDLINE, EMBASE, Global Health, the Cochrane Library, and PubMed (for ahead-of-print publications) for relevant English-language studies. Maximally adjusted risk estimates were pooled under random- and fixed-effects meta-analysis to derive odds ratios (ORs) and 95% confidence intervals (CIs). We included 6 studies representing 183 388 participants. Heterozygnous familial hypercholesterolemia was associated with a higher risk of PAD (OR: 3.59 [95% CI: 1.30-9.89]). This trend was nonsignificantly preserved (OR: 2.96 [95% CI: 0.68-12.88]) in sensitivity analyses of genetically defined HeFH. Genetic HeFH was not associated with increased ischemic stroke risk (OR: 0.76 [95% CI: 0.37-1.58]) although possessing an LDL-C >4.9 mmol/L (190 mg/dL) was (OR: 1.42 [95% CI: 1.06-1.89]). We found clinical and genetic diagnoses of HeFH to be associated with increased PAD risk. Genetically confirmed HeFH may not confer an increased risk of ischemic stroke. Modest associations may exist between LDL-C and ischemic stroke risk in HeFH.

Vessel wall magnetic resonance imaging findings and surgical treatment in nilotinib-associated cerebrovascular disease: A case report

Nilotinib, a second-generation tyrosine kinase inhibitor, is considered as one of the most effective drugs for the treatment of chronic myeloid leukemia (CML); however, the use of nilotinib has been reported to be associated with vascular adverse events, such as peripheral arterial occlusive disease and ischemic heart disease. Moreover, there are few reports on cerebral vascular disease associated with nilotinib use. We herein describe the case of a 55-year-old male patient with CML, who presented with cerebral infarction and severe cerebrovascular stenosis that developed during nilotinib treatment. The patient was diagnosed with cerebral infarction and severe stenosis of the intracranial arteries associated with nilotinib use. Vessel wall magnetic resonance imaging (VW-MRI) revealed diffuse concentric thickening of the vessel wall, unlike ordinary patterns of atherosclerosis. The patient underwent direct revascularization (superficial temporal artery to middle cerebral artery bypass) and was successfully treated without recurrence. Based on this rare case, VW-MRI may be used to detect the morphological changes of the intracranial arteries that are associated with nilotinib use. Moreover, surgical revascularization may improve the prognosis of nilotinib-associated cerebrovascular diseases, such as severe stenosis or occlusion of the main trunk of the cerebral arteries, that cause brain ischemia.

Genetic polymorphisms in Sox17 associated with intracranial aneurysm in Chinese Han people: a genotype-phenotype study

PURPOSE

Genetic factors play a vital role in intracranial aneurysm (IA) onset and development. Studying the relationship between IA and the Sox17 polymorphisms in diverse populations is essential for establishing credibility.

PATIENTS AND METHODS

We collected blood samples derived from a total of 596 sporadic IA patients and 600 individual controls in several medical institutes in China. We used the Sequenom MassArray system for single nucleotide polymorphisms (SNPs) genotyping after DNA extraction. The SNPs data was tested and analyzed in PLINK (version 1.9). Multiple-testing was performed in PLINK to make the statistics more rigorous and accurate.

RESULTS

We found that the allelic G of rs1072737 (OR=1.303, genomic-control corrected P-value =0.001032) is a risk allele, while the allelic G of rs9298506 (OR=0.7253, genomic-control corrected P-value =0.01559) is a protective allele in Chinese Han people.

CONCLUSION

The allelic G of rs1072737 is a risk factor for IA, while the allelic G of rs9298506 serves as a protective factor for IA in Chinese Han people.

The management of childhood cancer survivors at risk for stroke: A Delphi survey of regional experts

BACKGROUND

Evidence is not available to guide management of childhood cancer survivors (CCS) at risk for radiation-associated cerebral vascular disease (CVD) and stroke. We propose to use a consensus-based methodology to describe the collective opinion of regional experts for the care of these patients and identify areas of controversy.

PROCEDURE

Thirty physicians from the New England region who care for CCS participated in a Delphi panel querying their management approach (imaging, laboratory tests, medications, counseling, referrals) to a CCS treated with cranial radiation formatted as five clinical scenarios (asymptomatic, small- and large-vessel CVD, transient ischemia, stroke) in three rounds of anonymous questionnaires. Consensus defined as ≥90% agreement.

RESULTS

Response rate was 100% for all three rounds. Panelists reached consensus on laboratory tests to assess stroke risk factors, stroke risk and prevention counseling, brain imaging to monitor survivors with known CVD, and acute care for stroke symptoms. Only 67% panelists agreed with MRI screening asymptomatic survivors with no history of CVD, 87% endorsed aspirin as stroke prevention for large-vessel CVD and 57% for small-vessel CVD. There was no consensus on specialty referrals. Overall, panelists practicing at large institutions and neurology subspecialists were more likely to advocate for screening, interventions, and referrals.

CONCLUSIONS

Despite lack of evidence to guide stroke prevention in CCS treated with cranial radiation, a panel of regional physicians reached consensus on managing most clinical scenarios. Controversial areas requiring further study are surveillance imaging for asymptomatic survivors, aspirin for stroke prevention, and indications for specialty referral.

Association between Airborne Fine Particulate Matter and Residents' Cardiovascular Diseases, Ischemic Heart Disease and Cerebral Vascular Disease Mortality in Areas with Lighter Air Pollution in China

Background: China began to carry out fine particulate matter (PM_2.5) monitoring in 2013 and the amount of related research is low, especially in areas with lighter air pollution. This study aims to explore the association between PM_2.5 and cardiovascular disease (CVD), ischemic heart disease (IHD) and cerebral vascular disease (EVD) mortality in areas with lighter air pollution. Methods: Data on resident mortality, air pollution and meteorology in Shenzhen during 2013–2015 were collected and analyzed using semi-parametric generalized additive models (GAM) with Poisson distribution of time series analysis. Results: Six pollutants were measured at seven air quality monitoring sites, including PM_2.5, PM₁₀, SO₂, NO₂, CO and O₃. The PM_2.5 daily average concentration was 35.0 ± 21.9 μg/m³; the daily average concentration range was from 7.1 μg/m³ to 137.1 μg/m³. PM_2.5 concentration had significant effects on CVD, IHD and EVD mortality. While PM_2.5 concentration of lag5 and lag02 rose by 10 μg/m³, the excess risk (ER) of CVD mortality were 1.50% (95% CI: 0.51–2.50%) and 2.09% (95% CI: 0.79–3.41%), respectively. While PM_2.5 concentration of lag2 and lag02 rose by 10 μg/m³, the ER of IHD mortality were 2.87% (95% CI: 0.71–5.07%) and 3.86% (95% CI: 1.17–6.63%), respectively. While PM_2.5 concentration of lag4 and lag04 rose by 10 μg/m³, the ER of EVD mortality were 2.09% (95% CI: 2.28–3.92%) and 3.08% (95% CI: 0.68–5.53%), respectively. Conclusions: PM_2.5 increased CVD mortality. The government needs to strengthen the governance of air pollution in areas with a slight pollution.

Small vessels, dementia and chronic diseases - molecular mechanisms and pathophysiology

Cerebral small vessel disease (SVD) is a major contributor to stroke, cognitive impairment and dementia with limited therapeutic interventions. There is a critical need to provide mechanistic insight and improve translation between pre-clinical research and the clinic. A 2-day workshop was held which brought together experts from several disciplines in cerebrovascular disease, dementia and cardiovascular biology, to highlight current advances in these fields, explore synergies and scope for development. These proceedings provide a summary of key talks at the workshop with a particular focus on animal models of cerebral vascular disease and dementia, mechanisms and approaches to improve translation. The outcomes of discussion groups on related themes to identify the gaps in knowledge and requirements to advance knowledge are summarized.

Neurologic Complications of Acute Posterior Multifocal Placoid Pigment Epitheliopathy: A Case Series of 4 Patients

Acute posterior multifocal placoid pigment epitheliopathy (APMPPE) is a self-limited idiopathic inflammatory ophthalmologic condition with characteristic funduscopic and fluorescein angiography findings. It is typically characterized by a flu-like prodrome followed by monocular or binocular vision loss. Often, prognosis is excellent with complete or near-complete recovery of vision. Rarely, however, APMPPE is associated with neurologic complications, including meningitis, cerebral vasculitis, and stroke. Treatment in patients with central nervous system (CNS) involvement involves steroids and ultimately other immunosuppressive therapy, as there can be significant resulting morbidity and mortality otherwise. Evidence or guidelines regarding duration of treatment are lacking. We present 4 patients diagnosed with APMPPE who demonstrate the spectrum of neurologic sequelae associated with APMPPE. The first 2 cases highlight cerebrospinal fluid lymphocytic pleocytosis as an indicator of active CNS inflammation and the potential utility of serial lumbar punctures (LPs) to guide treatment duration. Cases 3 and 4 demonstrate the neurovascular complications seen in CNS vasculitis. Case 4 also highlights the potential use of magnetic resonance vessel wall imaging (VWI) as a noninvasive means for disease surveillance and treatment guidance. This case series emphasizes the importance of recognition by neurologists of APMPPE as an entity associated with strokes and cerebral vasculitis in order to provide appropriate and timely treatment. Active CNS inflammation warrants continued aggressive immunosuppressant treatment, and we propose that serial LPs and/or magnetic resonance VWIs may be effective tools to guide disease surveillance and subsequent treatment duration.

Chronic cerebral hypoperfusion alters amyloid-β peptide pools leading to cerebral amyloid angiopathy, microinfarcts and haemorrhages in Tg-SwDI mice

Cerebral hypoperfusion is an early feature of Alzheimer's disease (AD) that influences the progression from mild cognitive impairment to dementia. Understanding the mechanism is of critical importance in the search for new effective therapies. We hypothesized that cerebral hypoperfusion promotes the accumulation of amyloid-β (Aβ) and degenerative changes in the brain and is a potential mechanism contributing to development of dementia. To address this, we studied the effects of chronic cerebral hypoperfusion induced by bilateral carotid artery stenosis on Aβ peptide pools in a transgenic mouse model of AD (transgenic mice with Swedish, Dutch and Iowa mutations in human amyloid precursor protein (APP) (Tg-SwDI)). Cerebrovascular integrity was characterized by quantifying the occurrence of microinfarcts and haemorrhages and compared with wild-type mice without Aβ. A significant increase in soluble Aβ peptides (Aβ40/42) was detected after 1 month of hypoperfusion in the parenchyma in parallel with elevated APP and APP proteolytic products. Following 3 months, a significant increase in insoluble Aβ40/42 was determined in the parenchyma and vasculature. Microinfarct load was significantly increased in the Tg-SwDI as compared with wild-type mice and further exacerbated by hypoperfusion at 1 and 3 months. In addition, the number of Tg-SwDI hypoperfused mice with haemorrhages was increased compared with hypoperfused wild-type mice. Soluble parenchymal Aβ was associated with elevated NADPH oxidase-2 (NOX2) which was exacerbated by 1-month hypoperfusion. We suggest that in response to hypoperfusion, increased Aβ production/deposition may contribute to degenerative processes by triggering oxidative stress promoting cerebrovascular disruption and the development of microinfarcts.

Carotid artery intima-media thickness associated with prognosis of intracranial branch atheromatous disease

BACKGROUND AND PURPOSE

Small deep brain infarcts are often caused by two different vascular pathologies: branch atheromatous disease (BAD) and lipohyalinotic degeneration (LD). In this study, we compare the clinical characteristics of BAD and LD and investigate the role of C-reactive protein (CRP), homocysteine (Hcy), and carotid artery intima-media thickness (IMT) in the prognosis of patients with BAD and LD.

METHODS

Of 262 adult patients with small deep infarcts, 104 were considered BAD and 158 were considered LD. Data compared included clinical information, prevalence of lacune and leukoaraiosis, Hcy, CRP, carotid artery IMT, deterioration during admission, and recurrence of ischemic stroke (IS) within 1 year.

RESULTS

Patients with LD have severe leukoaraiosis and higher prevalence of lacune and intracerebral hemorrhage compared with those with BAD. Patients with BAD have higher initial National Institutes of Health Stroke Scale scores and incidence of progressive motor deficits compared with those with LD; CRP is associated with the progression in both groups. There is no statistical difference of recurring risk of IS within 1 year between the two groups; by multivariable logistic regression analysis, carotid artery IMT was an independent risk factor for recurrence of IS in 1 year in patients with BAD.

CONCLUSION

BAD as an independent clinical entity has different clinical and radiological characteristics compared with LD. Carotid artery IMT is an independent risk factor for recurrence of IS in patients with BAD.

Quantitative assessment of rest and acetazolamide CBF using quantitative SPECT reconstruction and sequential administration of (123)I-iodoamphetamine: comparison among data acquired at three institutions

PURPOSE

A recently developed technique which reconstructs quantitative images from original projection data acquired using existing single-photon emission computed tomography (SPECT) devices enabled quantitative assessment of cerebral blood flow (CBF) at rest and after acetazolamide challenge. This study was intended to generate a normal database and to investigate its inter-institutional consistency.

METHODS

The three institutions carried out a series of SPECT scanning on 32 healthy volunteers, following a recently proposed method that involved dual administration of (123)I-iodoamphetamine during a single SPECT scan. Intra-institute and inter-institutional variations of regional CBF values were evaluated both at rest and after acetazolamide challenge. Functional images were pooled for both rest and acetazolamide CBF, and inter-institutional difference was evaluated among these images using two independent software programs.

RESULTS

Quantitative assessment of CBF images at rest and after acetazolamide was successfully achieved with the given protocol in all institutions. Intra-institutional variation of CBF values at rest and after acetazolamide was consistent with previously reported values. Quantitative CBF values showed no significant difference among institutions in all regions, except for a posterior cerebral artery region after acetazolamide challenge in one institution which employed SPECT device with lowest spatial resolution. Pooled CBF images at rest and after acetazolamide generated using two software programs showed no institutional differences after equalization of the spatial resolution.

CONCLUSIONS

SPECT can provide reproducible images from projection data acquired using different SPECT devices. A common database acquired at different institutions may be shared among institutions, if images are reconstructed using a quantitative reconstruction program, and acquired by following a standardized protocol.

Enhanced large conductance K+ channel activity contributes to the impaired myogenic response in the cerebral vasculature of Fawn Hooded Hypertensive rats

Recent studies have indicated that the myogenic response (MR) in cerebral arteries is impaired in Fawn Hooded Hypertensive (FHH) rats and that transfer of a 2.4 megabase pair region of chromosome 1 (RNO1) containing 15 genes from the Brown Norway rat into the FHH genetic background restores MR in a FHH.1(BN) congenic strain. However, the mechanisms involved remain to be determined. The present study examined the role of the large conductance calcium-activated potassium (BK) channel in impairing the MR in FHH rats. Whole-cell patch-clamp studies of cerebral vascular smooth muscle cells (VSMCs) revealed that iberiotoxin (IBTX; BK inhibitor)-sensitive outward potassium (K+) channel current densities are four- to fivefold greater in FHH than in FHH.1(BN) congenic strain. Inside-out patches indicated that the BK channel open probability (NPo) is 10-fold higher and IBTX reduced NPo to a greater extent in VSMCs isolated from FHH than in FHH.1(BN) rats. Voltage sensitivity of the BK channel is enhanced in FHH as compared with FHH.1(BN) rats. The frequency and amplitude of spontaneous transient outward currents are significantly greater in VSMCs isolated from FHH than in FHH.1(BN) rats. However, the expression of the BK-α and -β-subunit proteins in cerebral vessels as determined by Western blot is similar between the two groups. Middle cerebral arteries (MCAs) isolated from FHH rats exhibited an impaired MR, and administration of IBTX restored this response. These results indicate that there is a gene on RNO1 that impairs MR in the MCAs of FHH rats by enhancing BK channel activity.

Diabetes alters the expression of partial vasoactivators in cerebral vascular disease susceptible regions of the diabetic rat

BACKGROUND

The pathogenesis between cerebral vascular disease (CVD) and the endothelial dysfunction (ETD) remains elusive in diabetes. Therefore, we investigated the expression of partial vasoactivators which be closely relative to ETD in CVD susceptible brain regions in the diabetic rat. The aim was to search some possible pathogenesis.

METHODS

Diabetes was induced by a single intraperitoneal injection of streptozotocin and a high lipid/sugar diet. The expression of vasoactivators ET-1, CGRP, VCAM-1, ICAM-1 and P-selectin were assessed by immunohistochemical staining and measurement of optic density of positive cells in the frontal and temporal lobe, basal ganglia and thalamus at 4 weeks after establishment of the diabetic model.

RESULTS

The expression of ET-1, VCAM-1, ICAM-1 and P-selectin significantly increased and CGRP significantly decreased in the diabetic group, and the expression of these vasoactivators was significantly different among the frontal, temporal lobe, basal ganglia and thalamus, and among the emotion, splanchno-motor and neuroendocrine center in the diabetic group.

CONCLUSIONS

Diabetes alters the expression of partial vasoactivators in cerebral vascular disease susceptible regions of the diabetic rat. Therefore, we suggested that CVD complications in diabetes are partly caused by ETD via an imbalance expression of endothelial vasoactivators, which might be associated with dysfunction of emotion, autonomic nerve and endocrine center. However, further studies are warranted.

Hypothermia after acute ischemic stroke

Induced hypothermia after ischemic stroke is a promising neuroprotective therapy and is the most potent in pre-clinical models. Technological limitations and homeostatic mechanisms that maintain core body temperature, however, have limited the clinical application of hypothermia. Advances in intravascular cooling and successful trials of hypothermia after global cerebral ischemia, such as in cardiac arrest and neonatal asphyxia, have renewed interest in hypothermia for stroke.