Association between interleukin-6 levels and first-ever cerebrovascular events in patients with vascular risk factors

The effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on ischemic stroke and the possible underlying mechanisms

Purpose: As of November 28, 2020, COVID-19 has been reported in 220 countries with 61,036,793 confirmed cases and 1,433,316 confirmed deaths; countries became vigilant around the world. In addition to SARS-CoV-2 causing pneumonia, many studies have reported ischemic stroke in patients with COVID-19. This article describes the effects and possible underlying mechanisms of SARS-CoV-2 on ischemic stroke.Materials and methods: A literature search was performed using PubMed, Web of Science, and other COVID-dedicated databases and the combination of the keywords 'SARS-CoV-2', 'COVID-19' and 'ischemic stroke' up to November 28, 2020.Results: SARS-CoV-2 invades the host through angiotensin converting enzyme 2 (ACE2). ACE2 is expressed not only in the lungs, but also in the brain and vascular endothelial cells. SARS-CoV-2 infection might cause direct vascular disease or enhance the immunogenic thrombosis environment through several mechanisms. SARS-CoV-2 infection can modulate the host immune response and can cause inflammation, coagulation disorders, renin angiotensin system disorders, hypoxia, and stress disorders, which may lead to the occurrence of ischemic stroke.Conclusions: Some patients with COVID-19 can develop ischemic stroke. Ischemic stroke has a high risk of causing disability and is associated with a high mortality rate. It is hoped that when medical staff treat patients with COVID-19, they would pay attention to the occurrence of ischemic stroke to improve the prognosis of patients with COVID-19.

Targeting autonomic nervous system as a biomarker of well-ageing in the prevention of stroke

Stroke prediction is a key health issue for preventive medicine. Atrial fibrillation (AF) detection is well established and the importance of obstructive sleep apneas (OSA) has emerged in recent years. Although autonomic nervous system (ANS) appears strongly implicated in stroke occurrence, this factor is more rarely considered. However, the consequences of decreased parasympathetic activity explored in large cohort studies through measurement of ANS activity indicate that an ability to improve its activity level and equilibrium may prevent stroke. In support of these observations, a compensatory neurostimulation has already proved beneficial on endothelium function. The available data on stroke predictions from ANS is based on many long-term stroke cohorts. These data underline the need of repeated ANS evaluation for the general population, in a medical environment, and remotely by emerging telemedicine digital tools. This would help uncovering the reasons behind the ANS imbalance that would need to be medically adjusted to decrease the risk of stroke. This ANS unbalance help to draw attention on clinical or non-clinical evidence, disclosing the vascular risk, as ANS activity integrates the cumulated risk from many factors of which most are modifiable, such as metabolic inadaptation in diabetes and obesity, sleep ventilatory disorders, hypertension, inflammation, and lack of physical activity. Treating these factors may determine ANS recovery through the appropriate management of these conditions. Natural aging also decreases ANS activity. ANS recovery will decrease global circulating inflammation, which will reinforce endothelial function and thus protect the vessels and the associated organs. ANS is the whistle-blower of vascular risk and the actor of vascular health. Such as, ANS should be regularly checked to help draw attention on vascular risk and help follow the improvements in response to our interventions. While today prediction of stroke relies on classical cardiovascular risk factors, adding autonomic biomarkers as HRV parameters may significantly increase the prediction of stroke.

Circulating Interleukin-6 Levels and Incident Ischemic Stroke: A Systematic Review and Meta-analysis of Prospective Studies

BACKGROUND AND OBJECTIVES

Human genetic studies support a key role of interleukin-6 (IL-6) in the pathogenesis of ischemic stroke. However, there are only limited data from observational studies exploring circulating IL-6 levels as a risk factor for ischemic stroke. We set out to perform a systematic review and meta-analysis of aggregate data on cohort studies to determine the magnitude and shape of the association between circulating IL-6 levels and risk of incident ischemic stroke in the general population.

METHODS

Following the PRISMA guidelines, we systematically screened the PubMed search engine from inception to March 2021 for population-based prospective cohort studies exploring the association between circulating IL-6 levels and risk of incident ischemic stroke. We pooled association estimates for ischemic stroke risk with random-effects models and explored nonlinear effects in dose-response meta-analyses. Risk of bias was assessed with the Newcastle-Ottawa Scale (NOS). We used funnel plots and trim-to-fill analyses to assess publication bias.

RESULTS

We identified 11 studies (n = 27,411 individuals; 2,669 stroke events) meeting our eligibility criteria. Mean age of all included participants was 60.5 years and 54.8% were female. Overall, quality of the included studies was high (median 8 out of 9 NOS points, interquartile range 7-9). In meta-analyses, 1 SD increment in circulating log-transformed IL-6 levels was associated with a 19% increase in risk of incident ischemic stroke over a mean follow-up of 12.4 years (relative risk 1.19; 95% confidence interval 1.10 to 1.28). A dose-response meta-analysis showed a linear association between circulating IL-6 levels and ischemic stroke risk. There was only moderate heterogeneity and the results were consistent in sensitivity analyses restricted to studies of low risk of bias and studies fully adjusting for demographic and vascular risk factors. The results also remained stable following adjustment for publication bias.

DISCUSSION

Higher circulating IL-6 levels in community-dwelling individuals are associated with higher long-term risk of incident ischemic stroke in a linear pattern and independently of conventional vascular risk factors. Along with findings from genetic studies and clinical trials, these results provide additional support for a key role of IL-6 signaling in ischemic stroke.

Significance of changes in the concentration of inflammatory factors in blood or cerebrospinal fluid in evaluating the severity and prognosis of spontaneous cerebral hemorrhage: A systematic review and meta-analysis

OBJECTIVE

Spontaneous intracerebral hemorrhage (SICH) often leads to severe disability, while inflammation plays an important role in SICH-induced secondary brain injury. The purpose of this study was to investigate the value of inflammatory factors as a means of evaluating the prognosis of SICH and to investigate the relationship between inflammatory factors and the severity and prognosis of SICH.

METHODS

The articles published before November 1 2020 were searched through PubMed, EMBASE, Cochrane library and web of science. Revman5.3 was used, using the inverse variance model to pool the SMD of TNF-a and interleukin concentration.

RESULTS

A total of 25 studies involving 3333 subjects were included in this paper. The concentration of TNF-α in the blood or cerebrospinal fluid of severe SICH patients was significantly higher than that of milder SICH patients or healthy population; SICH patients with high TNF-α concentration had a 1.06 times greater odds of poor outcomes than patients with low TNF-α concentration, odds ratio (OR) = 1.06[95% CI, 1.01-1.12]. The concentration of interleukin-6 (IL-6) in severe SICH patients was significantly higher than that in milder SICH patients; patients with high IL-6 concentration had a 2.61 times greater odds of poor outcomes than patients with low IL-6 concentration, OR = 2.61[95% CI, 1.79-3.80].

CONCLUSIONS

The detection of concentrations of TNF-α and IL-6 in peripheral blood may be helpful for the objective and quantitative assessment of the severity and prognosis of patients with SICH, and have certain significance for the selection of appropriate treatment options.

Food anthocyanins decrease concentrations of TNF-α in older adults with mild cognitive impairment: A randomized, controlled, double blind clinical trial

BACKGROUND & AIMS

Vascular function, blood pressure and inflammation are involved in the pathogenesis of major chronic diseases, including both cardiovascular disease (CVD) and mild cognitive impairment (MCI). This study investigated the effects of food anthocyanins on microvascular function, 24-h ambulatory blood pressure (ABP) and inflammatory biomarkers in older adults with MCI.

METHODS AND RESULTS

Thirty-one participants with MCI [19 female, 12 male, mean age 75.3 (SD 6.9) years and body mass index 26.1 (SD 3.3) kg/m²], participated in a randomized, controlled, double-blind clinical trial (Australian New Zealand Clinical Trials Registry: ACTRN12618001184268). Participants consumed 250 mL fruit juice daily for 8 weeks, allocated into three groups: a) high dose anthocyanins (201 mg); b) low dose anthocyanins (47 mg); c) control. Microvascular function (Laser Speckle Contrast Imaging combined with a post-occlusive reactive hyperaemia test), 24h ABP and serum inflammatory biomarkers were assessed before and after the nutritional intervention.

RESULTS

Participants in the high anthocyanins group had a reduction in serum tumor necrosis factor alpha (TNF-α) (P = 0.002) compared to controls and the low anthocyanins group (all P's > 0.05). Serum IL-6, IL-1β, c-reactive protein, and parameters of microvascular function and 24h ABP were not altered by any treatment.

CONCLUSION

A daily high dose of fruit-based anthocyanins for 8 weeks reduced concentrations of TNF-α in older adults with MCI. Anthocyanins did not alter other inflammatory biomarkers, microvascular function or blood pressure parameters. Further studies with a larger sample size and longer period of follow-up are required to elucidate whether this change in the immune response will alter CVD risk and progression of cognitive decline.

Neurovascular Unit as a Source of Ischemic Stroke Biomarkers-Limitations of Experimental Studies and Perspectives for Clinical Application

Cerebral stroke, which is one of the most frequent causes of mortality and leading cause of disability in developed countries, often leads to devastating and irreversible brain damage. Neurological and neuroradiological diagnosis of stroke, especially in its acute phase, is frequently uncertain or inconclusive. This results in difficulties in identification of patients with poor prognosis or being at high risk for complications. It also makes difficult identification of these stroke patients who could benefit from more aggressive therapies. In contrary to the cardiovascular disease, no single biomarker is available for the ischemic stroke, addressing the abovementioned issues. This justifies the need for identifying of effective diagnostic measures characterized by high specificity and sensitivity. One of the promising avenues in this area is studies on the panels of biomarkers characteristic for processes which occur in different types and phases of ischemic stroke and represent all morphological constituents of the brains' neurovascular unit (NVU). In this review, we present the current state of knowledge concerning already-used or potentially applicable biomarkers of the ischemic stroke. We also discuss the perspectives for identification of biomarkers representative for different types and phases of the ischemic stroke, as well as for different constituents of NVU, which concentration levels correlate with extent of brain damage and patients' neurological status. Finally, a critical analysis of perspectives on further improvement of the ischemic stroke diagnosis is presented.

A 9-Year Longitudinal Study of Basilar Artery Diameter

Background Dilatation of the basilar artery ( BA ) has been recognized as a predictor of cardiovascular events ( CVE s). However, it is unclear if the longitudinal change in BA diameter (Δ BA ) is associated with CVE s. Methods and Results In a cohort of Japanese participants with vascular risk factors in an observational study, we evaluated the relationship of Δ BA to CVE s and the time course of the BA diameter. The short axis of the BA diameter was measured at the midpons level in T2-weighted images. Brain magnetic resonance imaging measurements included cerebral small-vessel disease, lacunars, and white matter hyperintensities. First, 493 patients were analyzed by the time-dependent Cox proportional hazards model to evaluate the association between Δ BA and CVE s, with adjustment for age, sex, vascular risk factors, and magnetic resonance imaging parameters. Second, we assessed the longitudinal Δ BA in 164 patients who underwent long-term follow-up magnetic resonance imaging, by linear regression analysis. In the mean follow-up of 8.7 years, 105 patients developed CVE s. A smaller Δ BA was independently associated with the high incidence of CVE s (hazard ratio, 0.36; 95% CI, 0.16-0.78; P=0.010; n=493). After a mean interval of 9.4 years, the average Δ BA was 0.41±0.46 mm (excluding patients with fetal-type circle of Willis). Progression of BA dilatation was associated with men but inversely associated with initial BA diameter and fetal-type circle of Willis (n=164). Conclusions BA diameter increased over time (excluding the patients with fetal-type circle of Willis), whereas Δ BA was inversely associated with the incidence of CVE s.

C-Reactive Protein Predicts Further Ischemic Events in Patients With Transient Ischemic Attack or Lacunar Stroke

Patients who have experienced a first cerebral ischemic event are at increased risk of recurrent stroke. There is strong evidence that low-level inflammation as measured by high sensitivity C-reactive protein (hs-CRP) is a predictor of further ischemic events. Other mechanisms implicated in the pathogenesis of stroke may play a role in determining the risk of secondary events, including oxidative stress and the adaptive response to it and activation of neuroprotective pathways by hypoxia, for instance through induction of erythropoietin (EPO). This study investigated the association of the levels of CRP, peroxiredoxin 1 (PRDX1, an indicator of the physiological response to oxidative stress) and EPO (a neuroprotective factor produced in response to hypoxia) with the risk of a second ischemic event. Eighty patients with a diagnosis of lacunar stroke or transient ischemic attack (TIA) were included in the study and a blood sample was collected within 14 days from the initial event. Hs-CRP, PRDX1, and EPO were measured by ELISA. Further ischemic events were recorded with a mean follow-up of 42 months (min 24, max 64). Multivariate analysis showed that only CRP was an independent predictor of further events with an observed risk (OR) of 1.14 (P = 0.034, 95% CI 1.01–1.29). No association was observed with the levels of PRDX1 or EPO. A receiver operating curve (ROC) determined a cut-off CRP level of 3.25 μg/ml, with a 46% sensitivity and 81% specificity. Low-level inflammation as detected by hs-CRP is an independent predictor of recurrent cerebrovascular ischemic events.

Effect of prior stroke on long-term outcomes of percutaneous coronary interventions in Chinese patients: A large single-center study

OBJECTIVES

To evaluate the effect of prior stroke on long-term outcomes in patients undergoing percutaneous coronary interventions (PCI).

BACKGROUND

Patients with coronary heart disease (CHD) and prior stroke history have more serious clinical and angiographic conditions, which make the choice of treatment strategy complex.

METHODS

A total of 10,724 consecutive patients who underwent PCI from January 2013 to December 2013 were enrolled. 2-Year clinical outcomes between patients with prior stroke (n = 1150) and those with no prior stroke (n =9574) were compared.

RESULTS

The proportion of patients with prior stroke was 10.72%. These patients had higher clinical risks (age, sex, and cardiovascular risk factors) and more extensive coronary disease (higher pre-PCI and residual SYNTAX scores). During the 2-year follow-up, patients with prior stroke had a higher incidence of major adverse cardiac and cerebrovascular events (MACCE), all-cause death, stent thrombosis and stroke than those without prior stroke (14.3% vs. 11.8%, p = 0.02; 2.3% vs. 1.1%, p < 0.01; 1.6% vs. 0.8%, p < 0.01; 3.3% vs. 1.1%, p < 0.01, respectively). Multivariable regression analyses identified a positive association between prior stroke and risk of stroke (HR = 2.07, 95%CI: 1.35-3.19, p < 0.01). Propensity score matched analyses (962 pairs) indicated that the only primary end point that differed in incidence between the groups was stroke and prior stroke was the only independent predictor of stroke (HR = 2.31, 95%CI: 1.20-4.45, p = 0.01).

CONCLUSIONS

Prior stroke history was the only predictor of risk of post-PCI stroke. The noncerebrovascular adverse events were not increased after adjusted analyses of baseline characteristics and propensity analyses.

Chorioretinal thinning in chronic kidney disease links to inflammation and endothelial dysfunction

BACKGROUND. Chronic kidney disease (CKD) is strongly associated with cardiovascular disease and there is an established association between vasculopathy affecting the kidney and eye. Optical coherence tomography (OCT) is a novel, rapid method for high-definition imaging of the retina and choroid. Its use in patients at high cardiovascular disease risk remains unexplored.

METHODS. We used the new SPECTRALIS OCT machine to examine retinal and retinal nerve fiber layer (RNFL) thickness, macular volume, and choroidal thickness in a prospective cross-sectional study in 150 subjects: 50 patients with hypertension (defined as a documented clinic BP greater than or equal to 140/90 mmHg (prior to starting any treatment) with no underlying cause identified); 50 with CKD (estimated glomerular filtration rate (eGFR) 8–125 ml/min/1.73 m²); and 50 matched healthy controls. We excluded those with diabetes. The same, masked ophthalmologist carried out each study. Plasma IL-6, TNF-α , asymmetric dimethylarginine (ADMA), and endothelin-1 (ET-1), as measures of inflammation and endothelial function, were also assessed.

RESULTS. Retinal thickness, macular volume, and choroidal thickness were all reduced in CKD compared with hypertensive and healthy subjects (for retinal thickness and macular volume P < 0.0001 for CKD vs. healthy and for CKD vs. hypertensive subjects; for choroidal thickness P < 0.001 for CKD vs. healthy and for CKD vs. hypertensive subjects). RNFL thickness did not differ between groups. Interestingly, a thinner choroid was associated with a lower eGFR (r = 0.35, P <0.0001) and, in CKD, with proteinuria (r = –0.58, P < 0.001) as well as increased circulating C-reactive protein (r = –0.57, P = 0.0002), IL-6 (r = –0.40, P < 0.01), ADMA (r = –0.37, P = 0.02), and ET-1 (r = –0.44, P < 0.01). Finally, choroidal thinning was associated with renal histological inflammation and arterial stiffness. In a model of hypertension, choroidal thinning was seen only in the presence of renal injury.

CONCLUSIONS. Chorioretinal thinning in CKD is associated with lower eGFR and greater proteinuria, but not BP. Larger studies, in more targeted groups of patients, are now needed to clarify whether these eye changes reflect the natural history of CKD. Similarly, the associations with arterial stiffness, inflammation, and endothelial dysfunction warrant further examination.

TRIAL REGISTRATION. Registration number at www.clinicalTrials.gov: NCT02132741.

SOURCE OF FUNDING. TR was supported by a bursary from the Erasmus Medical Centre, Rotterdam. JJMHvB was supported by a bursary from the Utrecht University. JRC is supported by a Rowling Scholarship. SB was supported by a Wellcome Trust funded clinical research fellowship from the Scottish Translational Medicine and Therapeutics Initiative, and by a Rowling Scholarship, at the time of this work. ND is supported by a British Heart Foundation Intermediate Clinical Research Fellowship (FS/13/30/29994).

Chorioretinal thinning relates to the degree of inflammation and kidney injury in patients with kidney disease.

Obesity and stroke: Can we translate from rodents to patients?

Obesity is a risk factor for stroke and is consequently one of the most common co-morbidities found in patients. There is therefore an identified need to model co-morbidities preclinically to allow better translation from bench to bedside. In preclinical studies, both diet-induced and genetically obese rodents have worse stroke outcome, characterised by increased ischaemic damage and an altered inflammatory response. However, clinical studies have reported an 'obesity paradox' in stroke, characterised by reduced mortality and morbidity in obese patients. We discuss the potential reasons why the preclinical and clinical studies may not agree, and review the mechanisms identified in preclinical studies through which obesity may affects stroke outcome. We suggest inflammation plays a central role in this relationship, as obesity features increases in inflammatory mediators such as C-reactive protein and interleukin-6, and chronic inflammation has been linked to worse stroke risk and outcome.

Increased Total Homocysteine Levels Predict the Risk of Incident Dementia Independent of Cerebral Small-Vessel Diseases and Vascular Risk Factors

BACKGROUND

Homocysteine has been identified as a potential risk factor for stroke, cerebral small-vessel diseases (SVD), and dementia.

OBJECTIVE

The present study aimed to investigate the predictive value of homocysteine levels on incident dementia while simultaneously controlling for MRI findings and vascular risk factors.

METHODS

Within a Japanese cohort of participants with vascular risk factors in an observational study, we evaluated the association between baseline total homocysteine (tHcy) levels (per 1 μmol/L and the tertile of tHcy), the prevalence of MRI-findings at baseline, and incident all-cause dementia. Baseline brain MRI was used to determine SVD (lacunas, white matter hyperintensities, and cerebral microbleeds [CMBs]) and atrophy (medial-temporal lobe atrophy and bicaudate ratio). Logistic regression analyses were used to estimate the cross-sectional association between tHcy and each of MRI findings. Cox proportional hazards analyses were performed to estimate the longitudinal association between tHcy and dementia.

RESULTS

In the 643 subjects (age: 67.2 ± 8.4 years, male: 59% ; education: 12.9 ± 2.6 years), multivariable analyses adjusted for several potential confounders, including estimated glomerular filtration rate (eGFR) and intima-media thickness, showed that highest tHcy tertile was associated with lacunas, CMBs, and strictly deep CMBs. During the mean 7.3-year follow-up (range: 2-13), 47 patients were diagnosed with dementia (Alzheimer's disease: 24; vascular dementia: 18; mixed-type: 3; other: 2). After adjusting for age, gender, APOE ɛ4, education, BMI, MMSE, hypertension, cerebrovascular events, eGFR, and MRI-findings, tHcy level (hazard ratios [HR]: 1.08, p = 0.043) and the highest tertile of tHcy (HR: 2.50, p = 0.047) for all-cause dementia remained significant.

CONCLUSIONS

Our results provide additional evidence of tHcy that contributes to increased susceptibility to dementia risk.

Silent Brain Infarction and Risk of Future Stroke: A Systematic Review and Meta-Analysis

BACKGROUND AND PURPOSE

Silent brain infarction (SBI) on magnetic resonance imaging has been proposed as a subclinical risk marker for future symptomatic stroke. We performed a systematic review and meta-analysis to summarize the association between magnetic resonance imaging-defined SBI and future stroke risk.

METHODS

We searched the medical literature to identify cohort studies involving adults with SBI detected by magnetic resonance imaging who were subsequently followed up for incident clinically defined stroke. Study data and quality assessment were recorded in duplicate with disagreements in data extraction resolved by a third reader. Strength association between magnetic resonance imaging-detected SBI and future symptomatic stroke was measured by an hazard ratio.

RESULTS

The meta-analysis included 13 studies (14 764 subjects) with a mean follow-up ranging from 25.7 to 174 months. SBI predicted the occurrence of stroke with a random effects crude relative risk of 2.94 (95% confidence interval, 2.24-3.86, P<0.001; Q=39.65, P<0.001). In the 8 studies of 10 427 subjects providing hazard ratio adjusted for cardiovascular risk factors, SBI was an independent predictor of incident stroke (hazard ratio, 2.08 [95% confidence interval, 1.69-2.56; P<0.001]; Q=8.99; P=0.25). In a subgroup analysis pooling 9483 stroke-free individuals from large population-based studies, SBI was present in ≈18% of participants and remained a strong predictor of future stroke (hazard ratio, 2.06 [95% confidence interval, 1.64-2.59]; P<0.01).

CONCLUSIONS

SBI is present in ≈1 in 5 stroke-free older adults and is associated with a 2-fold increased risk of future stroke. Future studies of in-depth stroke risk evaluations and intensive prevention measures are warranted in patients with clinically unrecognized radiologically evident brain infarctions.

Interleukin-6, interleukin-6 receptor gene variant, small-vessel disease and incident dementia

BACKGROUND AND PURPOSE

Mixed neurogenerative and vascular dementia has emerged as the leading cause of dementia in the elderly. Inflammation is implicated in atherosclerosis, cerebral small-vessel disease (SVD) as well as cognitive impairment. However, longitudinal data on the predictive value of circulating inflammatory markers including gene variants and magnetic resonance imaging (MRI) findings in incident dementia are scarce. It was investigated whether circulating interleukin-6 (IL-6), C-reactive protein (CRP) and gene variants increase dementia risk.

METHODS

In a cohort of Japanese participants with vascular risk factors in an observational study from 2001, the association between baseline IL-6, CRP levels, gene variants [interleukin-6 receptor (IL-6R), rs2228145; IL-6, rs2097677; CRP, rs3093059] and incident all-cause dementia was evaluated. Baseline MRI was used to determine SVD (lacuna, white matter hyperintensities) and atrophy (medial-temporal lobe atrophy, bicaudate ratio). Cox proportional hazards analyses were performed for predictors of dementia, adjusting for age, sex, apolipoprotein Eε4, education, cerebrovascular events, vascular risk factors and MRI findings.

RESULTS

Of 803 subjects (mean 67.0 ± 8.5 years, males 59%), during a mean of 7.5 ± 3.2 years follow-up, 60 incident dementia patients (Alzheimer's disease 31; vascular dementia 17; mixed-type six; other six) were diagnosed. In multivariable analyses adjusted for age, sex, cerebrovascular events, MRI findings and IL-6R variant (rs2228145), IL-6 levels (relative risk 1.68, P = 0.048) or highest tertile (relative risk 2.38, P = 0.031) for all-cause dementia remained significant. Although subjects with rs2228145 carrier had significantly higher IL-6 levels, a significant association between rs2228145 and dementia was not observed. Conversely, CRP and remaining gene variants were not associated with dementia.

CONCLUSIONS

The deleterious effect of higher IL-6 on dementia remains consistent irrespective of conventional risk factors, MRI findings and IL-6R variant.

Blood and CSF biomarkers in brain subcortical ischemic vascular disease: Involved pathways and clinical applicability

Vascular dementia is the second most common type of dementia after Alzheimer’s disease (AD). Subcortical ischemic vascular disease refers to a form of vascular cognitive impairment characterized by the presence of diffuse white matter hyperintensities (WMHs) and multiple lacunar infarcts. These neuroimaging findings are mainly caused by cerebral small-vessel disease (cSVD) and relate to aging and cognitive impairment, but they can also be silent and highly prevalent in otherwise healthy individuals. We aimed to review studies on blood and cerebrospinal fluid (CSF) markers related to the presence of WMHs and lacunar infarcts that have been conducted in the past in large population-based studies and in high-risk selected patients (such as those with vascular risk factors, vascular cognitive impairment, or AD). Relevant associations with the presence and progression of cSVD have been described in the blood for markers related to inflammatory processes, endothelial damage and coagulation/fibrinolysis processes, etc. Also, different combinations of CSF markers might help to differentiate between etiologic types of dementia. In the future, to translate these findings into clinical practice and use biomarkers to early diagnosis and monitoring vascular cognitive impairment would require the replication of candidate markers in large-scale, multicenter, and prospectively designed studies.

Initial research on the relationship between let-7 family members in the serum and massive cerebral infarction

Eighty-eight ischemic stroke patients with massive cerebral infarction (MCI) who met our selection criteria were included in this study. MCI was assessed using the Glasgow Coma Scale (GCS) at hospital admission and at 2 weeks. The sera of all patients and controls were sampled at 48 h after the patients' attacks, and the sera of patients with MCI who had no severe cardiopulmonary complications, including those with hemorrhagic transformation (HT), were sampled again at 2 weeks. The relative expression of let-7 miRNA in the serum was determined by real-time qRT-PCR, and the blood levels of lipids, glucose, high-sensitivity C-reactive protein (hs-CRP), homocysteine and blood pressure were measured at admission. Interleukin-6 (IL-6) levels were detected by ELISA, and a luciferase assay was performed to confirm that IL-6 was a gene target of let-7. The relative expression of let-7f was significantly down-regulated in MCI without HT patients compared with controls (P<0.001), and it was positively correlated with GCS (P<0.01) and negatively correlated with hs-CRP (P<0.01). The relative expression of let-7f was significantly up-regulated in MCI patients with HT (P<0.01). IL-6 is a direct target gene for let-7f, and IL-6 expression was increased in MCI without HT patients compared to controls (P<0.01). The expression of let-7f in serum is associated with MCI without HT, which specifically inhibits IL-6. This suggests that let-7f may control inflammation in patients with MCI without HT.

Interleukin-1 and acute brain injury

Inflammation is the key host-defense response to infection and injury, yet also a major contributor to a diverse range of diseases, both peripheral and central in origin. Brain injury as a result of stroke or trauma is a leading cause of death and disability worldwide, yet there are no effective treatments, resulting in enormous social and economic costs. Increasing evidence, both preclinical and clinical, highlights inflammation as an important factor in stroke, both in determining outcome and as a contributor to risk. A number of inflammatory mediators have been proposed as key targets for intervention to reduce the burden of stroke, several reaching clinical trial, but as yet yielding no success. Many factors could explain these failures, including the lack of robust preclinical evidence and poorly designed clinical trials, in addition to the complex nature of the clinical condition. Lack of consideration in preclinical studies of associated co-morbidities prevalent in the clinical stroke population is now seen as an important omission in previous work. These co-morbidities (atherosclerosis, hypertension, diabetes, infection) have a strong inflammatory component, supporting the need for greater understanding of how inflammation contributes to acute brain injury. Interleukin (IL)-1 is the prototypical pro-inflammatory cytokine, first identified many years ago as the endogenous pyrogen. Research over the last 20 years or so reveals that IL-1 is an important mediator of neuronal injury and blocking the actions of IL-1 is beneficial in a number of experimental models of brain damage. Mechanisms underlying the actions of IL-1 in brain injury remain unclear, though increasing evidence indicates the cerebrovasculature as a key target. Recent literature supporting this and other aspects of how IL-1 and systemic inflammation in general contribute to acute brain injury are discussed in this review.

The role of T cells in the development of cardiovascular disease in HIV-infected patients

Cardiovascular disease (CVD) is highly prevalent in HIV-infected patients. Besides the classical cardiovascular risk factors, HIV related factors play a role, such as immune activation and treatment with highly active antiretroviral therapy (HAART). The resulting T cell activation is regarded as one of the driving forces behind this accelerated atherogenesis. Interventions, such as early treatment and anti-inflammatory therapy, decreasing T cell activation might lead to a lower incidence of CVD in future HIV infected patients. This review specifically explores the role of T cells in the development of atherosclerosis in HIV-infected patients.

Interleukin-10 protects against aging-induced endothelial dysfunction

Carotid and cerebrovascular disease increase markedly with age contributing to stroke and cognitive impairment. Inflammation is a key element of vascular disease. In these studies, we tested the hypothesis that interleukin-10 (IL-10), a potent anti-inflammatory cytokine, protects against aging-induced endothelial dysfunction. Responses of carotid arteries from adult (5 ± 1 months) and old (22 ± 1 months) wild-type and IL-10-deficient mice were examined in vitro. Acetylcholine (an endothelium-dependent agonist) produced relaxation in arteries from adult wild-type that was not altered in old mice. In contrast, relaxation to acetylcholine in arteries from old IL-10-deficient mice was reduced by ∼50% (P < 0.05). Tempol, a scavenger of superoxide, did not affect responses in adult or old wild-type mice, but restored vasodilation to acetylcholine to normal in old IL-10-deficient mice. Responses of the carotid artery to nitroprusside (an endothelium-independent agonist) were not altered in any group. Vascular expression of IL-6 (a proinflammatory mediator of vascular disease) and components of NADPH oxidase (a major source of superoxide) was increased in old IL-10-deficient mice compared with wild-type (P < 0.05). These findings provide the first evidence that age-related and superoxide-mediated endothelial dysfunction occurs earlier with IL-10 deficiency. Our findings suggest a novel role for IL-10 to protect against age-related increases in expression of IL-6, oxidative stress, and endothelial dysfunction.

Clinical depression, antidepressant use and risk of future cardiovascular disease

Many studies have shown that depression contributes to a higher risk of developing cardiovascular disease (CVD). Use of antidepressants and its association with CVD development has also been investigated previously but the results have been conflicting. Further, depression and use of antidepressants have been more widely studied in relation to coronary heart disease rather than stroke. A population-based cohort study consisting of 36,654 Swedish elderly twins was conducted with a follow-up of maximum 4 years. Information on exposures, outcomes and covariates were collected from the Swedish national patient registers, the Swedish prescribed drug registry and the Swedish twin registry. Depression and antidepressant use were both associated with CVD development. The risk was most pronounced among depressed patients who did not use antidepressants (HR 1. 48, CI 1.10-2.00). When assessing the two main CVD outcomes coronary heart disease and ischemic stroke separately, the predominant association was found for ischemic stroke while it was absent for coronary heart disease. The association between depression and stroke also remained significant when restricting to depression diagnoses occurring at least 10 years before baseline. The study supports that depression is a possible risk factor for development of CVD. Moreover, the hazard rate for CVD outcomes was highest among depressed patients who had not used antidepressants. The association with clinical depression is more marked in relation to stroke and disappears in relation to development of coronary heart disease.