Serum levels of intercellular adhesion molecule-1 and E-selectin in patients with acute ischaemic stroke

Soluble adhesion molecules and functional outcome after ischemic stroke: A Mendelian randomization study

OBJECTIVES

We employed Mendelian randomization to determine whether genetically predicted circulating levels of endothelial-derived adhesion molecules (soluble intercellular adhesion molecule-1 [sICAM-1]), soluble vascular-leukocyte adhesion molecule-1 [sVCAM-1], and soluble-endothelial-leukocyte adhesion molecule [sE-selectin]) were associated with functional outcome after ischemic stroke.

METHODS

Independent genetic variants robustly associated with soluble adhesion molecules, located at or close to the coding gene (cis), were used as genetic instruments. The functional outcome was evaluated using the 3-month modified Rankin Scale (mRS) score after ischemic stroke. A poor functional outcome was defined as mRS ≥ 3 at 3 months. We extracted summary data for functional outcome after ischemic stroke from the Genetics of Ischaemic Stroke Functional Outcome network (n = 6,021).

RESULTS

Genetically elevated sICAM-1 (OR 1.28, 95% CI 1.05-1.56) and sE-selectin (OR 2.69, 95% CI 1.23-5.86) levels were related with poor post-stroke outcome. However, we found no evidence that genetically elevated sVCAM-1 were associated with post-stroke outcome (OR 1.36, 95% CI 0.39-4.66).

CONCLUSIONS

We found that genetically elevated higher sICAM-1 and sE-selectin levels are associated with poor post-stroke outcome. Further studies are warranted to evaluate the potential of ICAM-1 and E-selectin to be drug targets for post-stroke recovery.

Inflammatory biomarkers of ischemic stroke

Ischemic stroke remains the second leading cause of death and among the major causes of morbidity worldwide. Therapeutic options are currently limited to early reperfusion strategies, while pharmacological neuroprotective strategies despite showing promising results in the experimental setting constantly failed to enter the clinical arena. Inflammation plays an important role in the pathophysiology of ischemic stroke and mediators of inflammation have been longtime investigated as possible prognostic marker and therapeutic target for stroke patients. Here, we summarized available evidence on the role of cytokines, soluble adhesion molecules and adipokines in the pathophysiology, prognosis and therapy of ischemic stroke.

Short-term exposure to JUUL electronic cigarettes can worsen ischemic stroke outcome

Background

The short and long-term health effects of JUUL electronic cigarette (e-Cig) are largely unknown and warrant extensive research. We hypothesized that JUUL exposure could cause cerebrovascular toxicities impacting the progression and outcome of ischemic stroke comparable to tobacco smoke (TS) exposure.

Methods

We exposed male C57 mice to TS/JUUL vapor for 14 days. LCMS/MS was used to measure brain and plasma nicotine and cotinine level. Transient middle cerebral artery occlusion (tMCAO) followed by reperfusion was used to mimic ischemic stroke. Plasma levels of IL-6 and thrombomodulin were assessed by enzyme-linked immunosorbent assay. At the same time, western blotting was used to study blood–brain barrier (BBB) tight junction (TJ) proteins expression and key inflammatory and oxidative stress markers.

Results

tMCAO upregulated IL-6 and decreased plasma thrombomodulin levels. Post-ischemic brain injury following tMCAO was significantly worsened by JUUL/TS pre-exposure. TJ proteins expression was also downregulated by JUUL/TS pre-exposure after tMCAO. Like TS, exposure to JUUL downregulated the expression of the antioxidant Nrf2. ICAM-1 was upregulated in mice subjected to tMCAO following pre-exposure to TS or JUUL, with a greater effect of TS than JUUL.

Conclusions

These results suggest that JUUL exposure could negatively impact the cerebrovascular system, although to a lesser extent than TS exposure.

Adhesion of Leukocytes to Cerebral Venules Precedes Neuronal Cell Death and Is Sufficient to Trigger Tissue Damage After Cerebral Ischemia

Background

Leukocytes contribute to tissue damage after cerebral ischemia; however, the mechanisms underlying this process are still unclear. This study investigates the temporal and spatial relationship between vascular leukocyte recruitment and tissue damage and aims to uncover which step of the leukocyte recruitment cascade is involved in ischemic brain injury.

Methods

Male wild-type, ICAM-1-deficient, anti-CD18 antibody treated, or selectin-deficient [fucusyltransferase (FucT IV/VII^−/−)] mice were subjected to 60 min of middle cerebral artery occlusion (MCAo). The interaction between leukocytes and the cerebrovascular endothelium was quantified by in vivo fluorescence microscopy up to 15 h thereafter. Temporal dynamics of neuronal cell death and leukocyte migration were assessed at the same time points and in the same tissue volume by histology.

Results

In wild-type mice, leukocytes started to firmly adhere to the wall of pial postcapillary venules two hours after reperfusion. Three hours later, neuronal loss started and 13 h later, leukocytes transmigrated into brain tissue. Loss of selectin function did not influence this process. Application of an anti-CD18 antibody or genetic deletion of ICAM-1, however, significantly reduced tight adhesion of leukocytes to the cerebrovascular endothelium (-60%; p < 0.01) and increased the number of viable neurons in the ischemic penumbra by 5-fold (p < 0.01); the number of intraparenchymal leukocytes was not affected.

Conclusions

Our findings suggest that ischemia triggers only a transient adhesion of leukocytes to the venous endothelium and that inhibition of this process is sufficient to partly prevent ischemic tissue damage.

Understanding the Connection Between Common Stroke Comorbidities, Their Associated Inflammation, and the Course of the Cerebral Ischemia/Reperfusion Cascade

Despite the enormous progress in the understanding of the course of the ischemic stroke over the last few decades, a therapy that effectively protects neurovascular units (NVUs) and significantly improves neurological functions in stroke patients has still not been achieved. The reasons for this state are unclear, but it is obvious that the cerebral ischemia and reperfusion cascade is a highly complex phenomenon, which includes the intense neuroinflammatory processes, and comorbid stroke risk factors strongly worsen stroke outcomes and likely make a substantial contribution to the pathophysiology of the ischemia/reperfusion, enhancing difficulties in searching of successful treatment. Common concomitant stroke risk factors (arterial hypertension, diabetes mellitus and hyperlipidemia) strongly drive inflammatory processes during cerebral ischemia/reperfusion; because these factors are often present for a long time before a stroke, causing low-grade background inflammation in the brain, and already initially disrupting the proper functions of NVUs. Broad consideration of this situation in basic research may prove to be crucial for the success of future clinical trials of neuroprotection, vasculoprotection and immunomodulation in stroke. This review focuses on the mechanism by which coexisting common risk factors for stroke intertwine in cerebral ischemic/reperfusion cascade and the dysfunction and disintegration of NVUs through inflammatory processes, principally activation of pattern recognition receptors, alterations in the expression of adhesion molecules and the subsequent pathophysiological consequences.

The Inflammatory Response After Ischemic Stroke: Targeting β2 and β1 Integrins

Ischemic stroke is a leading cause of death and disability with limited therapeutic options. Resulting inflammatory mechanisms after reperfusion (removal of the thrombus) result in cytokine activation, calcium influx, and leukocytic infiltration to the area of ischemia. In particular, leukocytes migrate toward areas of inflammation by use of integrins, particularly integrins β1 and β2. Integrins have been shown to be necessary for leukocyte adhesion and migration, and thus are of immediate interest in many inflammatory diseases, including ischemic stroke. In this review, we identify the main integrins involved in leukocytic migration following stroke (α L β2, αDβ2, α4β1, and α5β1) and targeted clinical therapeutic interventions.

Inflammatory molecules might become both biomarkers and therapeutic targets for stroke management

Stroke is the fifth leading cause of death and the most frequent cause of disability worldwide. Currently, stroke diagnosis is based on neuroimaging; therefore, the lack of a rapid tool to diagnose stroke is still a major concern. In addition, therapeutic approaches to combat ischemic stroke are still scarce, since the only approved therapies are directed toward restoring blood flow to the affected brain area. However, due to the reduced time window during which these therapies are effective, few patients benefit from them; therefore, alternative treatments are urgently needed to reduce stroke brain damage in order to improve patients' outcome. The inflammatory response triggered after the ischemic event plays an important role in the progression of stroke; consequently, the study of inflammatory molecules in the acute phase of stroke has attracted increasing interest in recent decades. Here, we provide an overview of the inflammatory processes occurring during ischemic stroke, as well as the potential for these inflammatory molecules to become stroke biomarkers and the possibility that these candidates will become interesting neuroprotective therapeutic targets to be blocked or stimulated in order to modulate inflammation after stroke.

Hypothermia and brain inflammation after cardiac arrest

The cessation (ischemia) and restoration (reperfusion) of cerebral blood flow after cardiac arrest (CA) induce inflammatory processes that can result in additional brain injury. Therapeutic hypothermia (TH) has been proven as a brain protective strategy after CA. In this article, the underlying pathophysiology of ischemia-reperfusion brain injury with emphasis on the role of inflammatory mechanisms is reviewed. Potential targets for immunomodulatory treatments and relevant effects of TH are also discussed. Further studies are needed to delineate the complex pathophysiology and interactions among different components of immune response after CA and identify appropriate targets for clinical investigations.

The development of biological therapies for neurological diseases: moving on from previous failures

INTRODUCTION

Although years of research have expanded the use of biologics for several clinical conditions, such development has not yet occurred in the treatment of neurological diseases. With the advancement of biologic technologies, there is promise for these therapeutics as novel therapeutic approaches for neurological diseases. Areas covered: In this article, the authors review the therapeutic potential of different types of biologics for the treatment of neurological diseases. Preclinical and clinical studies that investigate the efficacy and safety of biologics in the treatment of neurological diseases, namely Alzheimer's disease, amyotrophic lateral sclerosis, Parkinson disease, multiple sclerosis, and stroke, were reviewed. Moreover, the authors describe the key challenges in the development of therapeutically safe and effective biologics for the treatment of neurological diseases. Expert opinion: Several biologics have shown promise in the treatment of neurological diseases. However, the complexity of the CNS, as well as a limited understanding of disease progression, and restricted access of biologics to the CNS has limited successful development. Therefore, more research needs to be conducted to overcome these hurdles before developing effective and safe biologics for neurological diseases. The emergence of new technologies for the design, production and delivery of biologics will accelerate translating biologics to the clinic.

Systematic studies on the in vivo substance basis and the pharmacological mechanism of Acanthopanax Senticosus Harms leaves by UPLC-Q-TOF-MS coupled with a target-network method

The leaves of Acanthopanax Senticosus Harms (ASL) can be used as a food ingredient and also as raw materials for making tea and wine.

Clinical Trials of Immunomodulation in Ischemic Stroke

Inflammatory mechanisms are currently considered as a prime target for stroke therapy. There is evidence from animal studies that immune signals and mediators can have both detrimental and beneficial effects in particular stages of the disease process. Moreover, several of these mechanisms are turned on with sufficient delay after ischemia onset to make them amenable to therapeutic intervention. Several clinical proof-of concept trials have investigated the efficacy of different immunomodulatory approaches in patients with stroke. Trials targeting the innate immune system have focused on reduction of microglial activation, inhibition of neutrophil migration, and interleukin-1 receptor blockade, suggesting that interleukin-1 receptor blockade may be a promising strategy. Studies aiming at halting T-cell migration have also been undertaken with controversial findings regarding prevention of infarct growth in neuroimaging studies. Consistently, recent proof-of-concept trials targeting lymphocytes with drugs such as natalizumab and fingolimod have yielded some promising results on clinical endpoints, but confirmation in larger trials is needed. At present, the understanding of the role of immune mechanisms in neurorepair and neurodegeneration is limited. Improving long-term brain function by mitigating prolonged neuroinflammation that was triggered by acute brain injury could be a strategy in addition to neuroprotection.

Immune interventions in stroke

Approaches for the effective management of acute stroke are sparse, and many measures for brain protection fail. However, our ability to modulate the immune system and modify the progression of multiple sclerosis is increasing. As a result, immune interventions are currently being explored as therapeutic interventions in acute stroke. In this Review, we compare the immunological features of acute stroke with those of multiple sclerosis, identify unique immunological features of stroke, and consider the evidence for immune interventions. In patients with acute stroke, microglial activation and cell death products trigger an inflammatory cascade that damages vessels and the parenchyma within minutes to hours of the ischaemia or haemorrhage. Immune interventions that restrict brain inflammation, vascular permeability and tissue oedema must be administered rapidly to reduce acute immune-mediated destruction and to avoid subsequent immunosuppression. Preliminary results suggest that the use of drugs that modify disease in multiple sclerosis might accomplish these goals in ischaemic and haemorrhagic stroke. Further elucidation of the immune mechanisms involved in stroke is likely to lead to successful immune interventions.

The Immune Response to Acute Focal Cerebral Ischemia and Associated Post-stroke Immunodepression: A Focused Review

It is currently well established that the immune system is activated in response to transient or focal cerebral ischemia. This acute immune activation occurs in response to damage, and injury, to components of the neurovascular unit and is mediated by the innate and adaptive arms of the immune response. The initial immune activation is rapid, occurs via the innate immune response and leads to inflammation. The inflammatory mediators produced during the innate immune response in turn lead to recruitment of inflammatory cells and the production of more inflammatory mediators that result in activation of the adaptive immune response. Under ideal conditions, this inflammation gives way to tissue repair and attempts at regeneration. However, for reasons that are just being understood, immunosuppression occurs following acute stroke leading to post-stroke immunodepression. This review focuses on the current state of knowledge regarding innate and adaptive immune activation in response to focal cerebral ischemia as well as the immunodepression that can occur following stroke. A better understanding of the intricate and complex events that take place following immune response activation, to acute cerebral ischemia, is imperative for the development of effective novel immunomodulatory therapies for the treatment of acute stroke.

Association between intercellular adhesion molecule-1 gene K469E polymorphism and the risk of stroke in a Chinese population: a meta-analysis

Several epidemiologic studies have evaluated the association between intercellular adhesion molecule-1 (ICAM-1) gene K469E polymorphism and stroke, but the results were inconsistent. The present meta-analysis was performed to investigate the relationship between K469E polymorphism and stroke in the Chinese population. A comprehensive search for related studies from the electronic databases of PubMed, Embase, Web of Science, CBMdisc and CNKI as well as a manual search of the references of identified articles was performed. Data were extracted to calculate for allelic, additive, dominant and recessive models using pooled odds ratios (ORs) along with 95% confidence intervals (CIs) by Review Manager 5.0 and Stata 11.0. Different effect models, subgroup analysis, sensitivity analysis, publication bias and power calculations were used to improve the comprehensive analysis. Finally, a total of 12 studies containing 1593 cases and 1555 controls were included in the final meta-analysis. No evidence of significant association between ICAM-1 gene K469E polymorphism and stroke was found in all four models (allelic model: OR = 1.07, 95%CI = 0.78-1.47; additive model: OR = 1.21, 95% CI = 0.67-2.16 (EE vs. KK); OR = 1.04, 95%CI = 0.75-1.45 (EK vs. KK); dominant model: OR = 1.07, 95% CI = 0.73-1.56; and recessive model: OR = 1.18, 95% CI = 0.77-1.83, respectively) based on the overall population, as well as subgroup analysis and sensitivity analysis. In conclusion, the present meta-analysis showed no evidence of significant association between ICAM-1 gene K469E polymorphism and stroke in the Chinese population. Nonetheless, this conclusion should be interpreted cautiously due to the low statistical power and considerable heterogeneity. Therefore, larger sample-size studies with homogeneous cases and well-matched controls are needed to further address this correlation.

MRI of ICAM-1 upregulation after stroke: the importance of choosing the appropriate target-specific particulate contrast agent

PURPOSE

Magnetic resonance imaging (MRI) with targeted contrast agents provides a promising means for diagnosis and treatment monitoring after cerebrovascular injury. Our goal was to demonstrate the feasibility of this approach to detect the neuroinflammatory biomarker intercellular adhesion molecule-1 (ICAM-1) after stroke and to establish a most efficient imaging procedure.

PROCEDURES

We compared two types of ICAM-1-functionalized contrast agent: T 1-shortening gadolinium chelate-containing liposomes and T2(*)-shortening micron-sized iron oxide particles (MPIO). Binding efficacy and MRI contrast effects were tested in cell cultures and a mouse stroke model.

RESULTS

Both ICAM-1-targeted agents bound effectively to activated cerebrovascular cells in vitro, generating significant MRI contrast-enhancing effects. Direct in vivo MRI-based detection after stroke was only achieved with ICAM-1-targeted MPIO, although both contrast agents showed similar target-specific vascular accumulation.

CONCLUSIONS

Our study demonstrates the potential of in vivo MRI of post-stroke ICAM-1 upregulation and signifies target-specific MPIO as most suitable contrast agent for molecular MRI of cerebrovascular inflammation.

Inflammation after stroke: mechanisms and therapeutic approaches

Reperfusion of ischemic brain can reduce injury and improve outcome, but secondary injury due to inflammatory mechanisms limits the efficacy and time window of such treatments for stroke. This review summarizes the cellular and molecular basis of inflammation in ischemic injury as well as possible therapeutic strategies.

Role of inflammation and its mediators in acute ischemic stroke

Inflammation plays an important role in the pathogenesis of ischemic stroke and other forms of ischemic brain injury. Increasing evidence suggests that inflammatory response is a double-edged sword, as it not only exacerbates secondary brain injury in the acute stage of stroke but also beneficially contributes to brain recovery after stroke. In this article, we provide an overview on the role of inflammation and its mediators in acute ischemic stroke. We discuss various pro-inflammatory and anti-inflammatory responses in different phases after ischemic stroke and the possible reasons for their failures in clinical trials. Undoubtedly, there is still much to be done in order to translate promising pre-clinical findings into clinical practice. A better understanding of the dynamic balance between pro- and anti-inflammatory responses and identifying the discrepancies between pre-clinical studies and clinical trials may serve as a basis for designing effective therapies.

Higher plasma fractalkine is associated with better 6-month outcome from ischemic stroke

BACKGROUND AND PURPOSE

Fractalkine (CX3CL1) is a unique chemokine that is constitutively expressed on neurons where it serves as an adhesion molecule for lymphocytes and monocytes. CX3CL1 may also be cleaved from the surface of these cells and enter the circulation to act as a traditional chemokine. CX3CL1 could thus influence the inflammatory response after stroke. We hypothesized that patients with higher plasma CX3CL1 after stroke would have a more robust inflammatory response and experience worse outcome.

METHODS

Plasma CX3CL1 concentrations were assessed in 85 patients who were part of a larger study evaluating immune responses after ischemic stroke; CX3CL1 values were available from Day 1 to Day 180 after stroke onset. CX3CL1 was correlated to measures of inflammation and its effect on outcome assessed.

RESULTS

At 1 day after stroke, CX3CL1 was lower in patients with severe strokes. At 180 days after stroke, CX3CL1 concentrations were lower in patients with poor outcome. The association of CX3CL1 and outcome at 180 days was independent of initial stroke severity. Plasma CX3CL1 at 180 days was inversely associated with systemic markers of inflammation, including white blood cell counts and high-sensitivity C-reactive protein.

CONCLUSIONS

In contrast to our original hypothesis, lower concentrations of CX3CL1 are associated with worse stroke outcome. In light of recent studies suggesting an immunomodulatory and neuroprotective role for CX3CL1 in a variety of neurodegenerative diseases, a therapeutic role for CX3CL1 in stroke recovery should be considered.

Activated leukocyte cell adhesion molecule and prognosis in acute ischemic stroke

BACKGROUND AND PURPOSE

Biomarkers predicting mortality and functional outcome in stroke may be clinically helpful in identification of patients likely to benefit from intervention. Activated leukocyte cell adhesion molecule (ALCAM) is upregulated during neuroinflammation; we investigated whether ALCAM concentrations are associated with long-term mortality after ischemic stroke.

METHODS

In 244 patients with acute ischemic stroke (age 69±13 years), samples of ALCAM were obtained serially from presentation to Day 5 and after 6 months. Patients with overt ischemic heart disease and atrial fibrillation were excluded. The patients were followed for 47 months with all-cause and cardiovascular mortality as end points.

RESULTS

At follow-up, 72 patients (29%) had died, 43 due to cardiovascular causes. Patients with ALCAM in the fourth quartile (>46.8 ng/mL) at admission had a significantly poorer survival rate on univariate analysis (P<0.001); other time points did not add further but provided similar prognostic information. In multivariate analysis, after adjustment for age, stroke severity, C-reactive protein levels, troponin T levels, and heart and/or renal failure, ALCAM levels above the fourth quartile remained an independent predictor of long-term mortality (adjusted hazard ratio, 2.05; 95% CI, 1.11 to 3.76; P=0.021) and cardiovascular mortality (adjusted hazard ratio, 2.54; 95% CI, 1.06 to 6.07; P=0.028).

CONCLUSIONS

ALCAM levels measured at admission of acute ischemic stroke are associated with long-term mortality.

The dual role of the neuroinflammatory response after ischemic stroke: modulatory effects of hypothermia

Neuroinflammation is a key element in the ischemic cascade after cerebral ischemia that results in cell damage and death in the subacute phase. However, anti-inflammatory drugs do not improve outcome in clinical settings suggesting that the neuroinflammatory response after an ischemic stroke is not entirely detrimental. This review describes the different key players in neuroinflammation and their possible detrimental and protective effects in stroke. Because of its inhibitory influence on several pathways of the ischemic cascade, hypothermia has been introduced as a promising neuroprotective strategy. This review also discusses the influence of hypothermia on the neuroinflammatory response. We conclude that hypothermia exerts both stimulating and inhibiting effects on different aspects of neuroinflammation and hypothesize that these effects are key to neuroprotection.

Evaluation of platelet activation, coagulation, and fibrinolytic activation in patients with symptomatic lacunar stroke

BACKGROUND

It is unclear whether hemostasis plays a role in the pathogenesis of ischemic stroke subtypes.

OBJECTIVE

We aimed to investigate the possible relationship between different hemostatic markers and lacunar stroke.

RESULTS

The study consisted of 30 patients with symptomatic lacunar stroke and 30 healthy age-matched healthy individuals. We analyzed the values of "Mean Platelet Volume," D-dimer, "soluble p-selectin," "Plasminogen Activator Inhibitor Type-1" (PAI-1), "Thrombin-Activatable Fibrinolysis Inhibitor" (TAFI), and "Platelet Factor 4" (PF4) in patients with lacunar infarct and compared these values to those of control individuals. There were significant differences for D-dimer, mean platelet volume, thrombin-activatable fibrinolysis inhibitor, and platelet factor 4 values in symptomatic lacunar stroke group compared with the control group (P < 0.01).

CONCLUSIONS

Different hemostatic factors may play a role in the pathogenesis of lacunar stroke. Evaluating the role of hemostatic factors on different types of strokes may help us identify new therapeutic strategies and different prognostic stratifications for ischemic stroke.

Serum markers of cerebral ischemia

Rapid diagnosis and management of stroke patients is becoming increasingly important with the emergence of new interventional strategies for acute cerebral ischemia. A biochemical surrogate of cerebral ischemia, rapidly detectable in the serum before radiological diagnosis, might have clinical utility in the setting of acute stroke, high-risk cardiovascular procedures, and subarachnoid hemorrhage. Such a marker might also aid in the neurological prognosis of anoxic brain injury. Several serum markers have been evaluated in acute cerebral ischemia. These include neuronal enzymes such as neuron-specific enolase; markers of glial injury and activation, such as protein S100beta; and mediators of inflammation, such as interleukin-6. The clinical and preclinical data supporting the use of these biochemical surrogates of cerebral ischemia are reviewed.

Molecular mechanisms of apoptosis in cerebral ischemia: multiple neuroprotective opportunities

Cerebral ischemia/reperfusion (I/R) injury triggers multiple and distinct but overlapping cell signaling pathways, which may lead to cell survival or cell damage. There is overwhelming evidence to suggest that besides necrosis, apoptosis do contributes significantly to the cell death subsequent to I/R injury. Both extrinsic and intrinsic apoptotic pathways play a vital role, and upon initiation, these pathways recruit downstream apoptotic molecules to execute cell death. Caspases and Bcl-2 family members appear to be crucial in regulating multiple apoptotic cell death pathways initiated during I/R. Similarly, inhibitor of apoptosis family of proteins (IAPs), mitogen-activated protein kinases, and newly identified apoptogenic molecules, like second mitochondrial-activated factor/direct IAP-binding protein with low pI (Smac/Diablo), omi/high-temperature requirement serine protease A2 (Omi/HtrA2), X-linked mammalian inhibitor of apoptosis protein-associated factor 1, and apoptosis-inducing factor, have emerged as potent regulators of cellular apoptotic/antiapoptotic machinery. All instances of cell survival/death mechanisms triggered during I/R are multifaceted and interlinked, which ultimately decide the fate of brain cells. Moreover, apoptotic cross-talk between major subcellular organelles suggests that therapeutic strategies should be optimally directed at multiple targets/mechanisms for better therapeutic outcome. Based on the current knowledge, this review briefly focuses I/R injury-induced multiple mechanisms of apoptosis, involving key apoptotic regulators and their emerging roles in orchestrating cell death programme. In addition, we have also highlighted the role of autophagy in modulating cell survival/death during cerebral ischemia. Furthermore, an attempt has been made to provide an encouraging outlook on emerging therapeutic approaches for cerebral ischemia.

Elevated soluble intercellular adhesion molecule-1 levels are associated with poor short-term prognosis in middle-aged patients with acute ischaemic stroke

BACKGROUND

There is increasing evidence that cellular adhesion molecules (CAMs) play an important role in the pathophysiology of acute ischaemic stroke. We examined the prognostic value of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) on in-hospital mortality in patients with ischaemic stroke.

METHODS

We recruited 241 consecutive patients <or=65 years of age who were admitted with acute ischaemic stroke. Serum levels of sICAM-1 and sVCAM-1 were determined within 12 h from admission. Seventy-six subjects without evidence of cardiovascular disease, matched for age and sex, served as controls.

RESULTS

Patients with acute ischaemic stroke had higher sICAM levels compared to controls [267 (220-325) versus 200 (179-225) ng/ml, p<0.001]. Sixteen (6.6%) patients died during hospitalization. sICAM-1 and sVCAM-1 levels were significantly higher in patients who died compared to those who survived [370 (324-453) versus 260 (219-313) ng/ml, p<0.001 and 790 (495-985) versus 576 (494-671) ng/ml, p=0.01, respectively] but only sICAM-1 levels were independently associated with early death, after adjusting for various confounding factors. For 10 ng/ml increase in sICAM-1 levels there was a 9% higher risk of dying. Cut-off point analysis revealed that sICAM-1 levels >322 ng/ml were the optimal points that discriminated those who died from the rest of the patients.

CONCLUSIONS

High sICAM-1 levels on admission are associated with early death in ischaemic middle-aged stroke patients suggesting a pathogenetic role of inflammation in the evolution of ischaemic stroke.

Molecular targets in cerebral ischemia for developing novel therapeutics

Cerebral ischemia (stroke) triggers a complex series of biochemical and molecular mechanisms that impairs the neurologic functions through breakdown of cellular integrity mediated by excitotoxic glutamatergic signalling, ionic imbalance, free-radical reactions, etc. These intricate processes lead to activation of signalling mechanisms involving calcium/calmodulin-dependent kinases (CaMKs) and mitogen-activated protein kinases (MAPKs) such as extracellular signal-regulated kinase (ERK), p38, and c-Jun N-terminal kinase (JNK). The distribution of these transducers bring them in contact with appropriate molecular targets leading to altered gene expression, e.g. ERK and JNK mediated early gene induction, responsible for activation of cell survival/damaging mechanisms. Moreover, inflammatory reactions initiated at the neurovascular interface and alterations in the dynamic communication between the endothelial cells, astrocytes and neurons are thought to substantially contribute to the pathogenesis of the disease. The damaging mechanisms may proceed through rapid nonspecific cell lysis (necrosis) or by active form of cell demise (apoptosis or necroptosis), depending upon the severity and duration of the ischemic insult. A systematic understanding of these molecular mechanisms with prospect of modulating the chain of events leading to cellular survival/damage may help to generate the potential strategies for neuroprotection. This review briefly covers the current status on the molecular mechanisms of stroke pathophysiology with an endeavour to identify potential molecular targets such as targeting postsynaptic density-95 (PSD-95)/N-methyl-d-aspartate (NMDA) receptor interaction, certain key proteins involved in oxidative stress, CaMKs and MAPKs (ERK, p38 and JNK) signalling, inflammation (cytokines, adhesion molecules, etc.) and cell death pathways (caspases, Bcl-2 family proteins, poly (ADP-ribose) polymerase-1 (PARP-1), apoptosis-inducing factor (AIF), inhibitors of apoptosis proteins (IAPs), heat shock protein 70 (HSP70), receptor interacting protein (RIP), etc., besides targeting directly the genes itself. However, selecting promising targets from various signalling cascades, for drug discovery and development is very challenging, nevertheless such novel approaches may lead to the emergence of new avenues for therapeutic intervention in cerebral ischemia.

Inflammation in adult and neonatal stroke

This chapter will discuss the current knowledge of the contribution of systemic and local inflammation in acute and sub-chronic stages of experimental stroke in both the adult and neonate. It will review the role of specific cell types and interactions among blood cells, endothelium, glia, microglia, the extracellular matrix and neurons - cumulatively called "neurovascular unit" - in stroke induction and evolution. Intracellular inflammatory signaling pathways such as nuclear factor kappa beta and mitogen-activated protein kinases, and mediators produced by inflammatory cells such as cytokines, chemokines, reactive oxygen species and arachidonic acid metabolites, as well as the modifying role of age on these mechanisms, will be reviewed as well as the potential for therapy in stroke and hypoxic-ischemic injury.

Inflammation in stroke and focal cerebral ischemia

BACKGROUND

A growing number of recent investigations have established a critical role for leukocytes in propagating tissue damage after ischemia and reperfusion in stroke. Experimental data obtained from animal models of middle cerebral artery occlusion implicate inflammatory cell adhesion molecules, chemokines, and cytokines in the pathogenesis of this ischemic damage.

METHODS

Data from recent animal and human studies were reviewed to demonstrate that inflammatory events occurring at the blood-endothelium interface of the cerebral capillaries underlie the resultant ischemic tissue damage.

RESULTS

After arterial occlusion, the up-regulated expression of cytokines including IL-1, and IL-6 act upon the vascular endothelium to increase the expression of intercellular adhesion molecule-1, P-selectin, and E-selectin, which promote leukocyte adherence and accumulation. Integrins then serve to structurally modify the basal lamina and extracellular matrix. These inflammatory signals then promote leukocyte transmigration across the endothelium and mediate inflammatory cascades leading to further cerebral infarction.

CONCLUSIONS

Inflammatory interactions that occur at the blood-endothelium interface, involving cytokines, adhesion molecules, chemokines and leukocytes, are critical to the pathogenesis of tissue damage in cerebral infarction. Exploring these pathophysiological mechanisms underlying ischemic tissue damage may direct rational drug design in the therapeutic treatment of stroke.

Circulating markers of endothelial function in cardiovascular disease

Endothelial dysfunction is a key event in cardiovascular disease. Measurement of endothelial dysfunction in vivo presents a major challenge, but has important implications since it may identify the clinical need for therapeutic intervention, specifically in primary prevention. Several biological markers have been used as indicators of endothelial dysfunction. The soluble adhesion molecules sICAM-1 and sVCAM-1 lack specificity and are increased in inflammatory processes. Both markers are increased in coronary artery disease. sICAM-1 level predicts the risk for cardiovascular disease or diabetes mellitus in healthy individuals. sE-selectin is specific for the endothelium and is increased in coronary artery disease and diabetes mellitus. sE-selectin is also associated with diabetic risk. The endothelium-specific marker, soluble thrombomodulin, is associated with severity of coronary artery disease, stroke or peripheral occlusive arterial disease and is not increased in healthy or asymptomatic subjects. Interestingly, thrombomodulin decreases during treatment of hypercholesterolemia or hyperhomocysteinemia. In contrast, von Willebrand factor is the best endothelial biomarker and predicts risk for ischemic heart disease or stroke.

Association of Soluble Intercellular Adhesion Molecule 1 with Neurological Deterioration of Ischemic Stroke: The Chongqing Stroke Study

BACKGROUND

Adhesion molecules play important roles in the pathophysiology of ischemic stroke. The aim of the present study was to investigate whether serum levels of soluble intercellular adhesion molecule 1 (sICAM-1), soluble vascular cellular adhesion molecule 1 (sVCAM-1) and soluble E-selectin were associated with neurological deterioration of ischemic stroke.

METHODS

238 consecutive patients with ischemic stroke examined within 24 h from onset were enrolled into the study. The stroke severity was daily assessed with the NIH Stroke Scale (NIHSS) within the first week after admission. Serum levels of sICAM-1, sVCAM-1 and sE-selectin after admission were measured using enzyme-linked immunosorbent assay. Multivariate logistic regression was used to analyze the association of serum levels of sICAM-1, sVCAM-1 and sE-selectin on admission with the neurological deterioration of ischemic stroke, adjusted for potential confounders.

RESULTS

52 (21.8%) out of 238 stroke patients suffered from neurological deterioration. Serum levels of sICAM-1 on admission of stroke patients were significantly higher than those of healthy controls. Compared with patients without deterioration, patients with neurological deterioration had higher levels of sICAM-1, but not of sVCAM-1 and sE-selectin. On multivariate logistic regression, the serum level of sICAM-1 on admission was associated with neurological deterioration of stroke (OR 2.92, 95% CI 1.41-6.05). Other variables associated with neurological deterioration were fasting serum glucose (OR 1.65, 95% CI 1.24-2.20), baseline fibrinogen (OR 1.31, 95% CI 1.13-1.52) and NIHSS score (OR 1.23, 95% CI 1.15-1.32).

CONCLUSIONS

The serum level of sICAM-1 on admission is associated with neurological deterioration of ischemic stroke.

Serum and cerebrospinal fluid concentrations of E-selectin in patients with aneurysmal subarachnoid hemorrhage

The goal of the present study was to determine concentrations of E-selectin in both cerebrospinal fluid (CSF) and serum of patients with aneurysmal subarachnoid hemorrhage (SAH) and to evaluate the correlation between the clinical parameters and E-selectin levels. Both CSF and serum samples obtained from 12 patients with aneurysmal SAH and 8 patients with hydrocephalus (control group) without any other known central nervous system disease were assayed for E-selectin by quantitative enzyme-linked immunosorbent assay and the results were compared between the two groups. Mean levels of soluble forms of E-selectin within the first 3 days and on the 5th and 7th days of SAH were 4.0 +/- 7.9, 2.8 +/- 5.2, and 3.1 +/- 4.9 ng/ml in the patient's CSF, and 33.7 +/- 9.2, 35.1 +/- 7.0, and 35.2 +/- 8.7 ng/ml in serum, respectively. In contrast, mean E-selectin levels were 0.1 +/- 0.2 ng/ml in CSF and 8.7 +/- 5.0 ng/ml in serum of control patients. The difference between groups was statistically significant regarding both CSF and serum E-selectin levels (P < 0.05). Thus, we have demonstrated a marked increase of E-selectin concentration in both CSF and serum of patients with aneurysmal SAH compared with control and suggest that blocking the interaction between E-selectin and vascular endothelium may have a beneficial effect on vasospasms.

Predictive value of soluble intercellular adhesion molecule-1 for risk of ischemic events in individuals with cerebrovascular disease

BACKGROUND AND PURPOSE

Cellular adhesion molecules may play a critical role in the inflammatory process leading to atherosclerosis. The purpose of this study was to determine whether soluble intercellular adhesion molecule-1 (sICAM-1) is a predictor of future ischemic events in high-risk individuals and also whether it is associated with carotid artery stenosis.

METHODS

We conducted a prospective study of sICAM-1 concentration in 3 groups: (1) subjects with recent (< 7 days) ischemic stroke or TIA, (2) asymptomatic subjects with carotid stenosis > or = 50% and (3) asymptomatic individuals with vascular risk factors. Subjects were followed for a minimum of 3 years. sICAM-1 levels were compared between the groups and correlated with the risk of ischemic events and the degree of carotid artery stenosis.

RESULTS

We studied 275 subjects. Mean sICAM-1 levels were significantly higher in those with recent ischemic stroke or TIA compared to those with risk factors alone. During follow-up, ischemic events occurred almost nine times more frequently in subjects in group 1 compared to group 3. sICAM-1 concentration was not predictive of future ischemic events (OR 1.001, 95% CI 0.998-1.004). There was no significant association between sICAM-1 concentration and carotid artery stenosis (OR 1.001, 95% CI 0.999-1.004).

CONCLUSIONS

Mean sICAM-1 levels were higher in subjects with recent cerebral ischemia. No association between sICAM-1 and carotid artery stenosis was observed. Neither baseline nor subsequent sICAM-1 levels were predictive of the risk of future ischemic events.

Human cellular inflammation in the pathology of acute cerebral ischaemia

Leucocytes form important effector pathways for inflammation. This article reviews the clinical evidence for the presence of a cellular inflammatory response in cerebral ischaemia, and attempts to define its temporal profile and spatial distribution. The processes involved in recruitment and activation of leucocytes in this context are addressed, and the successes and failures of interventions aimed at these processes discussed.

Endothelial and platelet activation in acute ischemic stroke and its etiological subtypes

BACKGROUND AND PURPOSE

Activation of endothelial cells and platelets is an important mediator of atherothrombosis. Markers of endothelial cell and platelet activation such as soluble adhesion molecules can be measured in plasma. We hypothesized that patients with acute ischemic stroke would have increased blood concentrations of soluble E-selectin and von Willebrand factor (vWF), primarily reflecting activation of endothelial cells, and increased concentrations of soluble P-selectin and platelet-derived microvesicles (PDM), primarily reflecting activation of platelets, compared with healthy controls. We also hypothesized that these markers would be differentially elevated in ischemic stroke caused by large- and small-artery atherothrombosis compared with cardiogenic embolism.

METHODS

We conducted a case-control study of 200 hospital-referred cases of first-ever ischemic stroke and 205 randomly selected community controls stratified by age, sex, and postal code. Using established criteria, we classified cases of stroke by etiological subtype in a blinded fashion. The prevalence of vascular risk factors and blood concentrations of E-selectin, P-selectin, vWF antigen, and PDM were determined in stroke cases within 7 days and at 3 to 6 months after stroke and in controls.

RESULTS

Mean blood concentrations of soluble E-selectin, P-selectin, and PDM within 7 days of stroke onset were all significantly higher in cases compared with controls. At 3 to 6 months after stroke, the mean blood concentrations of E-selectin and P-selectin fell significantly below that of controls, and PDM concentrations remained elevated. There was a strong, graded, and independent (of age, sex, and vascular risk factors) association between increasing blood concentrations of E-selectin during the acute phase and all etiological subtypes of ischemic stroke, particularly ischemic stroke caused by large-artery atherothrombosis. There was also a significant, graded, and independent association between increasing blood concentrations of vWF during the acute phase and ischemic stroke caused by large-artery atherothrombosis.

CONCLUSIONS

We have demonstrated significant associations between acute elevation of blood markers of endothelial cell and platelet activation and ischemic stroke and between acute elevation of blood markers of endothelial cell activation and ischemic stroke caused by large-artery atherothrombosis. Persistent elevated blood concentrations of PDM may be a marker of increased risk of ischemic stroke.

High-dose ibuprofen for reduction of striatal infarcts during middle cerebral artery occlusion in rats

OBJECT

Ibuprofen is an antiinflammatory drug that disrupts leukocyte-endothelial cell interactions by limiting expression of endothelial adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1), also known as CD54. The authors hypothesized that ibuprofen could reduce the size of the infarct associated with transient focal ischemia by inhibition of ICAM-1 expression, and they evaluated its effects in rats treated with middle cerebral artery (MCA) occlusion. Ibuprofen treatment was compared with mild systemic hypothermia, which is known to be neuroprotective and is commonly used during neurosurgical procedures.

METHODS

The maximum ibuprofen dose (240 mg/kg/day) that could be tolerated with no systemic toxicity was established in the initial experiments. In the efficacy experiment, rats were pretreated with vehicle, ibuprofen, or hypothermia (33 degrees C) prior to 2 hours of MCA occlusion; then their brains were harvested at 24 hours of reperfusion for histological studies. End-ischemic cerebral blood flow (CBF) was evaluated using [14C]iodoantipyrine autoradiography in additional cohorts. Expression of ICAM-1 within ischemic compared with nonischemic caudate nucleus and putamen (striatum) or cortex was evaluated using immunohistochemical studies. Compared with vehicle treatment, ibuprofen produced a 46.2% reduction (p = 0.01) in striatal infarcts, which was comparable to hypothermia (48.7% reduction, p = 0.02). Ibuprofen did not alter end-ischemic CBF in any region studied, and the ibuprofen treatment group had the lowest proportion of animals with marked ICAM-1 staining.

CONCLUSIONS

Ibuprofen given in maximum tolerated doses reduces the striatal infarct size after focal cerebral ischemia. The neuroprotective mechanism does not work through preservation of intraischemic CBF and is consistent with inhibition of ICAM-1 expression; however, at the doses used in this study, other effects of ibuprofen on platelet and endothelial function are possible.

Inflammatory mechanisms after ischemia and stroke

Inflammation has been implicated as a secondary injury mechanism following ischemia and stroke. A variety of experimental models, including thromboembolic stroke, focal and global ischemia, have been used to evaluate the importance of inflammation. The vasculature endothelium promotes inflammation through the upregulation of adhesion molecules such as ICAM, E-selectin, and P-selectin that bind to circulating leukocytes and facilitate their migration into the CNS. Once in the CNS, the production of cytotoxic molecules may facilitate cell death. The macrophage and microglial response to injury may either be beneficial by scavenging necrotic debris or detrimental by facilitating cell death in neurons that would otherwise recover. While many studies have tested these hypotheses, the importance of inflammation in these models is inconclusive. This review summarizes data regarding the role of the vasculature, leukocytes, blood-brain barrier, macrophages, and microglia after experimental and clinical stroke.

Inflammation and infection in clinical stroke

Stroke has enormous clinical, social, and economic implications, and demands a significant effort from both basic and clinical science in the search for successful therapies. Atherosclerosis, the pathologic process underlying most coronary artery disease and the majority of ischemic stroke in humans, is an inflammatory process. Complex interactions occur between the classic risk factors for atherosclerosis and its clinical consequences. These interactions appear to involve inflammatory mechanisms both in the periphery and in the CNS. Central nervous system inflammation is important in the pathophysiologic processes occurring after the onset of cerebral ischemia in ischemic stroke, subarachnoid hemorrhage, and head injury. In addition, inflammation in the CNS or in the periphery may be a risk factor for the initial development of cerebral ischemia. Peripheral infection and inflammatory processes are likely to be important in this respect. Thus, it appears that inflammation may be important both before, in predisposing to a stroke, and afterwards, where it is important in the mechanisms of cerebral injury and repair. Inflammation is mediated by both molecular components, including cytokines, and cellular components, such as leukocytes and microglia, many of which possess pro- and/or antiinflammatory properties, with harmful or beneficial effects. Classic acute-phase reactants and body temperature are also modified in stroke, and may be useful in the prediction of events, outcome, and as therapeutic targets. New imaging techniques are important clinically because they facilitate dynamic evaluation of tissue damage in relation to outcome. Inflammatory conditions such as giant cell arteritis and systemic lupus erythematosus predispose to stroke, as do a range of acute and chronic infections, principally respiratory. Diverse mechanisms have been proposed to account for inflammation and infection-associated stroke, ranging from classic risk factors to disturbances of the immune and coagulation systems. Considerable opportunities therefore exist for the development of novel therapies. It seems likely that drugs currently used in the treatment of stroke, such as aspirin, statins, and modulators of the renin-angiotensin-aldosterone system, act at least partly via antiinflammatory mechanisms. Newer approaches have included antimicrobial and antileukocyte strategies. One of the most promising avenues may be the use of cytokine antagonism, for example, interleukin-1 receptor antagonist.

Endothelial cell activation is associated with cerebral white matter lesions in patients with cerebrovascular disease

Cerebral MRI scanning frequently shows white matter lesions in elderly people. They are related to cognitive impairment and may result in dementia. Although vascular risk factors are associated with the presence of white matter lesions, the exact pathogenesis remains unclear. Animal studies have indicated involvement of endothelial cells in the pathogenesis of white matter lesions and possibly dementia. We investigated the relation between endothelial cell activation and white matter lesions in individuals with cerebrovascular disease. In 29 patients with an acute stroke (n = 11) or TIAs associated with a symptomatic internal carotid artery stenosis (n = 18), markers of endothelial cell activation such as intercellular adhesion molecule-1 (sICAM-1), vascular cell adhesion molecule-1 (sVCAM-1), sE-selectin, and sP-selectin were measured by means of ELISA. All individuals underwent 1.5-T MRI scanning. White matter lesions were rated for the periventricular and the subcortical region separately. Individuals with severe periventricular white matter lesions had higher levels of sP-selectin (245.5 ng/mL vs. 172.7 ng/mL, p = 0.01) and sVCAM-1 (547.8 ng/mL vs. 454.0 ng/mL, p = 0.04) than those without. This association was only found in individuals with a symptomatic carotid artery stenosis. No such association was found for subcortical white matter lesions. We did not detect any relation between sICAM-1 and sE-selectin and white matter lesions. Endothelial cell activation may play a role in the pathogenesis of white matter lesions, especially in periventricular white matter. Possibly, this activation represents the influence of vascular factors on the cerebral endothelium as a prelude to increasingly severe small vessel disease.

sPECAM-1 in serum and CSF of acute ischaemic stroke patients

OBJECTIVES

As platelet endothelial cell adhesion molecule-1 (PECAM-1) is one of key mediators of transendothelial migration of leucocytes during inflammation, and inflammatory reaction is observed in cerebral ischaemia, we decided to determine the levels of soluble PECAM-1 (sPECAM-1) in serum and cerebrospinal fluid (CSF) of patients with acute stroke.

MATERIAL AND METHODS

Twenty-three patients with first-ever in a lifetime completed ischaemic stroke have been studied. CSF and blood samples were obtained within 24 h of the onset of stroke and the levels of sPECAM-1 in serum and CSF were quantified by ELISA.

RESULTS

Stroke patients displayed statistically significant higher levels of sPECAM-1 in sera and CSF in comparison with control group. The levels were significantly higher in serum than in CSF, correlated between each other, and CSF sPECAM-1 fraction was blood-derived.

CONCLUSION

Our results indirectly suggest that PECAM-1 may play a role in the pathophysiological events during early phase of ischaemic stroke.

Soluble intercellular adhesion molecule-1 and risk of future ischemic stroke: a nested case-control study from the Bezafibrate Infarction Prevention (BIP) study cohort

BACKGROUND AND PURPOSE

Inflammation is considered to be involved in the pathogenesis of ischemic stroke. Our purpose was to assess the role of soluble intercellular adhesion molecule-1 (sICAM-1) concentration, a marker of inflammation, in predicting future ischemic stroke among patients at risk because of chronic coronary heart disease.

METHODS

We obtained baseline serum samples from patients with chronic coronary heart disease enrolled in the Bezafibrate Infarction Prevention trial (n=3090), which assessed the efficacy of bezafibrate in secondary prevention. Using a prospective nested case-control design, we measured baseline sICAM-1 concentration in sera of patients who developed ischemic stroke during a mean follow-up of 8.2 years (cases, n=134) and in age- and sex-matched controls without any subsequent cardiovascular events (n=134).

RESULTS

Baseline serum concentrations of sICAM-1 were significantly higher in cases compared with controls (379 versus 350 ng/mL, P<0.05). sICAM-1 concentration at the highest quartile (>394 ng/mL) was associated with significantly higher relative odds of ischemic stroke compared with the lower concentrations after adjustment for potential confounding variables (relative odds, 2.1; 95% CI, 1.1 to 4.3). After fibrinogen and total white blood cell count were added to the multivariable model, the relative odds were 2.1 (95% CI, 1.1 to 4.2) and 2.2 (95% CI, 1.1 to 4.8), respectively. The risk associated with raised concentrations of sICAM-1 seemed to be highest for large disabling strokes of cardioembolic origin.

CONCLUSIONS

Elevated concentrations of sICAM-1, a marker of inflammation, are associated with increased risk of ischemic stroke, independent of other traditional cerebrovascular risk factors and of plasma fibrinogen, among patients at increased risk because of manifest coronary heart disease.

Rise in serum soluble intercellular adhesion molecule—1 levels with vasospasm following aneurysmal subarachnoid hemorrhage

Object. Proinflammatory adhesion molecule expression has been demonstrated to be elevated in patients with aneurysmal subarachnoid hemorrhage (SAH). Recent studies have shown that elevations in soluble intercellular adhesion molecule—1 (ICAM-1) may be predictive of poor outcome in patients with good grade (Hunt and Hess Grades 1–2) aneurysmal SAH at delayed time points that correspond with the risk period for cerebral vasospasm. In addition, ICAM-1 is upregulated in experimental models of vasospasm. Unfortunately, the relationship of adhesion molecule expression to human vasospasm remains unclear. The authors hypothesized that the delayed elevation of soluble ICAM-1 in patients with aneurysmal SAH is associated with the development of cerebral vasospasm.

Methods. Eighty-nine patients with aneurysmal SAH were prospectively enrolled in a study and stratified according to the presence or absence of vasospasm, as evidenced by daily monitoring of transcranial Doppler (TCD) velocities (presence, > 200 cm/second; absence, ≤ 120 cm/second). Levels of soluble ICAM-1 were determined using enzyme-linked immunosorbent assay every other day for 12 days post-SAH. An analysis of covariance model was used to evaluate trends in soluble ICAM-1 levels from 2 days prior to 6 days after the occurrence of documented vasospasm. Two groups of patients, matched for admission admission Hunt and Hess grade, were compared: nine patients with TCD velocities greater than 200 cm/second and nine patients with TCD velocities less than 120 cm/second. From among the patients with TCD velocities greater than 200 cm/second six patients with angiographically documented vasospasm were selected. Patients with TCD velocities less than 120 cm/second and matched admission Hunt and Hess grades but without angiographically documented vasospasm were selected. Patients with TCD-demonstrated vasospasm showed a significant mean rate of rise (p < 0.01) in soluble ICAM-1 levels during the perivasospasm period, but admission Hunt and Hess grade—matched control patients did not (p = not significant [NS]). There was a significant difference between these groups' rates of soluble ICAM increase (p < 0.01). Patients with both TCD- and angiographically demonstrated vasospasm likewise showed a highly significant mean rate of increase in soluble ICAM-1 levels during the perivasospasm period (p < 0.01), whereas admission Hunt and Hess grade—matched controls did not (p = NS). The difference beween these groups' rates of increase was highly significant (p < 0.001).

Conclusions. These data suggest a role for ICAM-1 in the pathophysiology of cerebral vasospasm or its ischemic sequelae. As this relationship is further elucidated, adhesion molecules such as ICAM-1 may provide novel therapeutic targets in the prevention of vasospasm or its ischemic consequences.

Inflammatory cell adhesion molecules in ischemic cerebrovascular disease

BACKGROUND

In this review we discuss the role of inflammatory cell adhesion molecules (CAMs) in ischemic stroke and in delayed cerebral ischemia after subarachnoid hemorrhage. Vascular endothelial cells and leukocytes express several inflammatory adhesion receptors, the most important of which are the selectins, immunoglobulin gene superfamily CAMs, and beta2 integrins. They mediate the transmigration process of leukocytes to the abluminal side of the endothelium.

SUMMARY OF REVIEW

There is ample evidence from animal models of middle cerebral artery occlusion that expression of CAMs is associated with cerebral infarct size. Absence of CAMs in knockout animals resulted in reduced infarct size. When middle cerebral artery occlusion in experimental stroke was followed by reperfusion, administration of anti-CAM antibodies decreased infarct size. Thus far, anti-CAM treatment has not been successful in patients with ischemic stroke. Inflammatory CAM may also play a role in the pathogenesis of delayed cerebral ischemia after subarachnoid hemorrhage. In animal models, increased expression of CAMs has been observed in vasospastic arteries. Increased concentrations of CAMs have also been found in cerebrospinal fluid of patients with subarachnoid hemorrhage.

CONCLUSIONS

Further research on the role of inflammatory CAMs in the pathogenesis of ischemic cerebrovascular disorders should lead to new diagnostic and therapeutic strategies.

Serum concentration of adhesion molecules in patients with delayed ischaemic neurological deficit after aneurysmal subarachnoid haemorrhage: the immunoglobulin and selectin superfamilies

OBJECTIVES

Adhesion molecules are involved in the pathogenesis of cerebral ischaemia and may play a part in the pathophysiology of delayed ischaemic neurological deficit (DIND) after aneurysmal subarachnoid haemorrhage. It was hypothesised that after aneurysmal subarachnoid haemorrhage, adhesion molecules may play a part in the pathophysiology of DIND as reflected by significantly altered serum concentrations in patients with and without DIND.

METHODS

In a prospective study, mean serum concentrations of ICAM-1, VCAM-1, PECAM, and E, P, and L-selectin were compared between patients without (n=23) and with (n=13) DIND in patients with World Federation of Neurological Surgeons (WFNS) grades 1 or 2 subarachnoid haemorrhage. Serum was sampled from patients within 2 days of haemorrhage and on alternate days until discharge. Concentrations of adhesion molecules were measured by standard procedures using commercially available enzyme linked immunoabsorbent assays.

RESULTS

There were non-significant differences in serum concentrations of ICAM-1 (290.8 ng/ml v 238.4 ng/ml, p=0.0525), VCAM-1 (553.2 ng/ml v 425.8 ng/ml, p=0.053), and PECAM (22.0 ng/ml v 21.0 ng/ml, p=0.56) between patients without and with DIND respectively. The E-selectin concentration between the two patient groups (44.0 ng/ml v 37.4 ng/ml, p=0.33) was similar. The P-selectin concentration, however, was significantly higher in patients with DIND compared with those patients without DIND (149.5 ng/ml v 112.9 ng/ml, p=0.039). By contrast, serum L-selectin concentrations were significantly lower in patients with DIND (633.8 ng/ml v 897.9 ng/ml, p=0.013).

CONCLUSIONS

Of all the adhesion molecules examined in this study, P and L-selectin are involved in the pathophysiology of DIND after aneurysmal subarachnoid haemorrhage.

Elevation of soluble intercellular adhesion molecule-1 levels in symptomatic and asymptomatic carotid atherosclerosis

OBJECTIVE

Recent data suggest that the increased expression of intercellular adhesion molecule-1 (ICAM-1) in atherosclerotic plaque taken from the carotid bifurcation correlates with the development of neurological symptoms. As a result, the authors sought to compare the serum levels of soluble forms of ICAM-1 (sICAM-1) in patients who were asymptomatic with those who were symptomatic for carotid artery stenosis as well as in patients who were matched in terms of sex, age, and risk factors who did not have carotid artery disease.

METHODS

Using enzyme-linked immunosorbent assay, serum sICAM-1 levels were prospectively determined in 54 patients scheduled to undergo carotid endarterectomy for either symptomatic or asymptomatic high-grade stenosis (> or =60%) and in 5 additional patient controls. Data are expressed as mean +/- standard error of the mean, with significance defined as P < 0.05 using the Mann-Whitney two-tailed test for two-column comparison or analysis of variance and Fisher protected least significant difference test.

RESULTS

Using a univariate model, serum sICAM-1 levels were significantly elevated in patients with carotid artery stenosis as compared with control patients without stenosis (347 +/- 15 ng/ml versus 216 +/- 8.2 ng/ml) (P < 0.01). When the asymptomatic and symptomatic patients with carotid artery stenosis were considered separately, these levels were still elevated relative to those of control patients (asymptomatic [312 +/- 18 ng/ml] and symptomatic [376 +/- 22 ng/ml] patients; P = 0.06 for asymptomatic versus control patients, P < 0.01 for symptomatic versus control patients). Symptomatic patients also had significantly elevated sICAM-1 levels as compared with asymptomatic patients (P < 0.05). Despite the fact that female patients demonstrated higher ICAM-1 levels than male patients (P < 0.05), sex, age, and risk factors such as the presence of hypercholesterolemia, diabetes, hypertension, or a history of smoking did not confound these findings.

CONCLUSION

Levels of sICAM-1 are higher in patients with carotid stenosis than in control patients. Symptomatic patients demonstrate significantly elevated levels as compared with asymptomatic patients. These data support the contention that ICAM-1 is a reliable marker of carotid disease progression and suggest that serum levels may be useful in following certain asymptomatic patients.

P-selectin antibody reduces hemorrhage and infarct volume resulting from MCA occlusion in the rat

We investigated the effect of an anti-P-selectin antibody (RMP-1) on ischemic cell damage and hemorrhage after transient middle cerebral artery occlusion (MCAo) in the rat. Animals were divided into four groups: (1) antibody (Ab) 1 group (n = 14) RMP-1 (2 mg/kg) was administered to rats 1 h prior to induction of 2 h of MCA occlusion; (2) control-vehicle group Ab2 (n = 12) rats were subjected to the same experimental protocol, except that an isotype-matched control antibody was administered; (3) Abl group (n = 10) rats were subjected to 2 h of MCA occlusion and RMP-1 (2 mg/kg) was administered upon reperfusion; (4) control-vehicle group Ab2 (n = 10) rats were subjected to the same experimental protocol, except that an isotype-matched control antibody was administered. Animals were sacrificed 48 h after onset of the MCAo for histological evaluation of infarction and hemorrhage, and to quantify number of neutrophils. The lesion volume was significantly smaller only in pretreated rats (RMP-1 group, 18.7+/-3.1%) compared to the vehicle-treated (31.6+/-2.6%) group (P<0.01). Total area of hemorrhage (5.94 x 10(3)+/-2.86 x 10(3) microm2) in the pre MCAo RMP-1 treated group animals was significantly reduced (P<0.02) compared to the vehicle group (6.1 x 10(4)+/-3.42 x 10(4) microm2), respectively. Our data demonstrate that administration of the anti-P-selectin antibody before transient focal cerebral ischemia in rat brain reduces ischemic cell damage and petechial hemorrhage.

A longitudinal prospective study of soluble adhesion molecules in acute stroke

BACKGROUND AND PURPOSE

Activation of endothelial cells is a consequence of cerebral ischemia and leads to the expression of adhesion molecules such as intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin, which can be released into the blood. This study aimed to define the kinetics of soluble adhesion molecule serum levels after cerebral ischemia and their correlation with the extent of neurological deficits, clinical outcome, and infarct volume as measured on CT scans. Methods-Plasma levels of soluble (s) ICAM-1, sVCAM-1, and sE-selectin were repeatedly determined by ELISA in 38 patients during a period of 14 days after acute cerebral ischemia.

RESULTS

Soluble adhesion molecule levels demonstrated considerable variability. Overall, concentrations revealed characteristic and significant changes after completed strokes but not after transient ischemic attacks. In patients with completed stroke (n=26) but not in patients with transient ischemic attacks (n=12), sICAM-1 peaked within 24 hours (P=0.04), sVCAM-1 reached a maximum after 5 days (P=0.02), and sE-selectin levels decreased after 5 days (P=0.002). There was no clear-cut correlation of soluble adhesion molecule levels with infarct volume or clinical disability. The initial increase of sE-selectin levels was higher in more disabled patients (P=0.02). sICAM-1 levels were higher in patients with signs of infection (n=9; P=0.03).

CONCLUSIONS

As a result of large interindividual variability influenced by ischemia-independent factors, soluble adhesion molecules are not reliable candidates as surrogate markers in acute cerebral ischemia. The characteristic profile of individual soluble adhesion molecules after completed stroke supports prior hypotheses of their involvement in the pathogenesis of acute cerebral ischemia, but this needs to be clarified in detail.