Solveig Horstmann

Profiles of Matrix Metalloproteinases, Their Inhibitors, and Laminin in Stroke Patients Influence of Different Therapies

BACKGROUND AND PURPOSE The goal of this study was to determine the temporal profile of several matrix metalloproteinases (MMPs), tissue inhibitors of MMPs (TIMPs), and laminin (an MMP substrate) in human stroke under different treatment paradigms, including thrombolysis and hypothermia. METHODS We serially measured the serum levels of MMP-2, MMP-3, MMP-9, MMP-13, TIMP-1, TIMP-2, and laminin in 50 patients with acute ischemic stroke using zymography or enzyme-linked immunosorbent assay. Patients were treated with heparin, therapeutic thrombolysis, or hypothermia. Scandinavian Stroke Scale scores were obtained at baseline. Infarct volume was measured with CT scanning on day 4 after stroke onset. Healthy persons were used as control subjects. RESULTS MMP-2 and MMP-9 increased during the course of ischemia, whereas intact laminin and TIMP-2 decreased significantly (P<0.05). MMP-9 and laminin levels varied significantly by infarct size (P=0.001) and therapy (P=0.0005). MMP-9 levels were significantly higher in patients treated with tissue plasminogen activator (tPA) compared with patients treated with hypothermia. The cleaved form of MMP-9 was found solely in 4 patients treated with tPA. Intact laminin levels were significantly lower in the tPA group than in the hypothermia group. CONCLUSIONS Selected MMPs and TIMPs are involved in the pathophysiology of acute stroke. This is also reflected by changes in laminin. Treatment paradigms differentially influence levels of MMP-9 and laminin. Combination therapies explicitly involving MMP inhibition could be of value in future treatment strategies.

Minocycline and hypothermia for reperfusion injury after focal cerebral ischemia in the rat—Effects on BBB breakdown and MMP expression in the acute and subacute phase

Reperfusion injury is a complication of recanalization therapies after focal cerebral ischemia. The disruption of the blood-brain barrier (BBB) caused by up-regulated metalloproteinases (MMPs) can lead to edema and hemorrhage. Middle cerebral artery occlusion (MCAO=90 min) and reperfusion (R=24 h vs. 5 days) was induced in male Wistar rats. Rats were randomized in four groups: (1) control (C), (2) twice daily minocycline (30 mg/kg bodyweight) every day (M), (3) hypothermia (33 degrees C) for 4 h starting 60 min after occlusion (H), (4) combination of groups 2 and 3 (MH). Serial MRI was performed regarding infarct evolution and BBB disruption, MMP-2 and MMP-9 were assessed by zymography of serum and ischemic brain tissue, and a functional neuroscore was done at 24 h and 5 days. M and H reduced both infarct sizes, volume and signal intensity of BBB breakdown and improved neuroscore at all points in time to the same extent. This was most likely due to inhibition of MMP-2 and MMP-9. The presence of MMP-9 at 24 h or MMP-2 at 5 days in brain tissue correlated with BBB breakdown whereas serum MMP-2- and -9 showed no relationship with BBB breakdown. The combination MH had a small but not significantly additional effect over the single treatments. Minocycline seems to be as neuroprotective as hypothermia in the acute and subacute phase after cerebral ischemia. One essential mechanism is the inhibition of MMPs. The combination therapy is only slightly superior. The net effect of MMPs inhibition up to 5 days after focal cerebral ischemia is still beneficial.

Matrix metalloproteinases in peripheral blood and cerebrospinal fluid in patients with Alzheimer's disease

BACKGROUND Deposition of amyloid beta in senile plaques and in cerebral blood vessels is one hallmark of the pathogenesis of Alzheimers disease (AD). The ability of several matrix metalloproteinases (MMPs) to degrade amyloid precursor protein leading to aggregation of amyloid beta, as well as the increased expression of MMPs in post mortem brain tissue of Alzheimers patients, indicate that MMPs play an important role in the pathogenesis of AD. METHODS We investigated levels of MMP-2,-3,-9 and -10 in plasma and cerebrospinal fluid (CSF) of AD patients (n = 14) by gelatin and casein zymography. Comparisons between AD patients and controls relative to levels of MMP-2, MMP-3, MMP-9, and MMP-10 were made with Wilcoxon rank statistics. Pearson correlations were computed as measures of association. RESULTS MMP-3 in AD was significantly elevated in plasma (p = 0.006) and there was a trend towards increase in CSF (p = 0.05). MMP-2 in CSF of AD patients was significantly decreased (p = 0.02) while levels in plasma remained unchanged. MMP-9 and MMP-10 could not be detected in CSF; MMP-10 was unchanged in plasma, but MMP-9 was significantly decreased (p = 0.02). CONCLUSIONS These findings constitute further evidence for the important role of MMPs in the pathogenesis of AD.

Gene expression in human peripheral blood mononuclear cells upon acute ischemic stroke

AbstractBackground and purposeIschemic stroke provokes a systemic inflammatory response. The purpose of this study was to characterize this response on the gene expression level in circulating mononuclear leukocytes from acute ischemic stroke (AIS) patients.MethodsRNA from peripheral blood mononuclear cells (PBMCs) of AIS patients (24 + 2 hours after onset of symptoms) was analyzed with Affymetrix U133A GeneChips using a pooled design. We compared the gene expression signature from AIS patients (n = 20), stroke survivors (n = 15), patients with acute traumatic brain injury (ATBI, n = 15) and healthy control subjects without vascular risk factors (n = 15).ResultsExpression levels of 9682 probe sets with present calls on each GeneChip were compared. Between AIS patients and stroke survivors or between AIS patients and ATBI patients there were no significant differences in expression values of single genes after correction for multiple testing. However, comparison of the PBMC expression profiles from AIS patients and healthy subjects revealed significantly different expression (p = 0.012) of a single probe set, specific for phosphodiesterase 4 D (PDE4D). In order to detect modest expression differences in multiple genes with a presumed cumulative effect we studied the gene expression of functional groups of genes by global statistical tests. Analysis of 11 gene groups revealed differential expression between AIS patients and healthy subjects for genes involved in the inflammatory response (GeneOntology GO:0006954). Genes encoding the N-formyl peptide receptor-like 1 (FPRL1), interleukin-1 receptor antagonist (IL1RN) and complement component 3a receptor 1 (C3AR1) contributed most to the observed difference.ConclusionsThis transcriptome analysis did not identify significant changes between circulating mononuclear cells from AIS patients 24 hours after stroke and closely matched stroke survivors. However, comparing AIS patients with healthy control subjects revealed measurable differences in PDE4D and in inflammatory response genes when considered as a set.

Reversal strategies for vitamin K antagonists in acute intracerebral hemorrhage

There is little evidence to guide treatment strategies for intracerebral hemorrhage on vitamin K antagonists (VKA‐ICH). Treatments utilized in clinical practice include fresh frozen plasma (FFP) and prothrombin complex concentrate (PCC). Our aim was to compare case fatality with different reversal strategies.

MMP-2 and MMP-9 levels in peripheral blood after subarachnoid hemorrhage.

MMPs play an important role in ischemic and hemorrhagic stroke. We analyzed replicate serum samples from 20 normal healthy individuals to assess reproducibility of MMP determinations, and found that MMP-2 and MMP-9 determinations were quite consistent. We then studied the serum levels of MMP-2 and MMP-9 in patients suffering from subarachnoid hemorrhage (SAH), another stroke subtype. Serum MMP-2 and MMP-9 levels from SAH patients were measured sequentially using gelatine zymography in 11 patients after acute SAH. The occurrence of intracerebral aneurysms and vasospasms and the initial Hunt and Hess score were analysed in relation to MMP-levels. MMP-2 levels are significantly decreased while MMP-9 levels are increased in SAH patients relative to controls. MMP-2 levels remain depressed out to day 12 post SAH, but MMP-9 levels may recover by day 12.

Diphenyleneiodonium and dimethylsulfoxide for treatment of reperfusion injury in cerebral ischemia of the rat.

Diphenyleneiodonium (DPI) is an inhibitor of the free radical producing NAD(P)H-oxidase. We tested whether DPI shows neuroprotective properties after focal cerebral ischemia and we used dimethylsulfoxide (DMSO), a nonspecific free radical scavenger, as a solvent. In male Wistar rats middle cerebral artery occlusion (1.5 h) and subsequent reperfusion (48 h) (MCAO/R) was induced with the filament model. Immediately after reperfusion the animals received either 0.25 ml normal saline, DMSO, or a combination of DMSO and DPI; each group consisted of 10 animals. MRI was performed at different times after reperfusion. Gelatine zymography of brain tissue for MMP-2 and MMP-9 was performed. The infarct sizes and BBB damage showed a significant difference between controls and the DPI/DMSO group for almost all points in time in all sequences. The activity of MMP-2 and MMP-9 was significantly reduced by DPI/DMSO but not by DMSO alone. DMSO treatment alone resulted in a protective effect with reduced lesion sizes measured by MRI at selected points of time, consistent with its known free radical scavenger effect. The combination of DMSO with DPI partly augmented this effect, presumably due to the additional inhibition of MMP-2 and MMP-9 by DPI. Moreover, the neurological outcome in both therapeutic groups was improved compared to controls with a significant difference between the therapeutic groups in favour of DPI and DMSO. The combination of DPI and DMSO reduced the activity of MMP-2 and MMP-9, attenuated the postischemic blood-brain barrier damage and improved neurological outcome. This was most likely due to reduced oxidative stress.

Left atrial appendage occlusion in atrial fibrillation after intracranial hemorrhage

Objective: To evaluate the safety and feasibility of percutaneous left atrial appendage occlusion (LAAO) in patients with atrial fibrillation (AF) and previous intracranial hemorrhage (ICH). Methods: In an explorative, prospective, single-center, observational study, LAAO was performed in patients with previous ICH and AF using the Amplatzer Cardiac Plug device. Risks of ischemic strokes and hemorrhagic complications were estimated using the CHA2DS2Vasc score and the HAS-BLED score. Before and 1, 6, 12, and 24 months after the procedure, clinical status and complications were recorded. Major complications were predefined as periprocedural stroke, death, pericardial effusion, and device embolism. Results: LAAO was performed in 20 patients. Based on CHA2DS2Vasc score (mean 4.5 ± 1.4) and HAS-BLED score (mean 4.7 ± 1.0), annual risks of stroke and hemorrhagic complications were 4.0%–6.7% and 8.7%–12.5%, respectively. No patient had a procedure-related complication. Minor postprocedural complications were observed in 4/20 patients (2 inguinal hematoma, 1 self-limiting asystole, and 1 thrombus formation on device). No ischemic or hemorrhagic stroke occurred during a mean follow-up of 13.6 ± 8.2 months. Conclusions: In this first study of LAAO in patients with previous ICH, LAAO appears feasible and safe. A larger, controlled trial is needed to assess the efficacy and safety of the procedure compared to other preventive measures. Classification of evidence: This study provides Class III evidence that in patients with a history of previous ICH and AF, percutaneous LAAO is safe and feasible.

Recurrent stroke risk and cerebral microbleed burden in ischemic stroke and TIA: A meta-analysis

Objective: To determine associations between cerebral microbleed (CMB) burden with recurrent ischemic stroke (IS) and intracerebral hemorrhage (ICH) risk after IS or TIA. Methods: We identified prospective studies of patients with IS or TIA that investigated CMBs and stroke (ICH and IS) risk during ≥3 months follow-up. Authors provided aggregate summary-level data on stroke outcomes, with CMBs categorized according to burden (single, 2–4, and ≥5 CMBs) and distribution. We calculated absolute event rates and pooled risk ratios (RR) using random-effects meta-analysis. Results: We included 5,068 patients from 15 studies. There were 115/1,284 (9.6%) recurrent IS events in patients with CMBs vs 212/3,781 (5.6%) in patients without CMBs (pooled RR 1.8 for CMBs vs no CMBs; 95% confidence interval [CI] 1.4–2.5). There were 49/1,142 (4.3%) ICH events in those with CMBs vs 17/2,912 (0.58%) in those without CMBs (pooled RR 6.3 for CMBs vs no CMBs; 95% CI 3.5–11.4). Increasing CMB burden increased the risk of IS (pooled RR [95% CI] 1.8 [1.0–3.1], 2.4 [1.3–4.4], and 2.7 [1.5–4.9] for 1 CMB, 2–4 CMBs, and ≥5 CMBs, respectively) and ICH (pooled RR [95% CI] 4.6 [1.9–10.7], 5.6 [2.4–13.3], and 14.1 [6.9–29.0] for 1 CMB, 2–4 CMBs, and ≥5 CMBs, respectively). Conclusions: CMBs are associated with increased stroke risk after IS or TIA. With increasing CMB burden (compared to no CMBs), the risk of ICH increases more steeply than that of IS. However, IS absolute event rates remain higher than ICH absolute event rates in all CMB burden categories.

Does the STAF score help detect paroxysmal atrial fibrillation in acute stroke patients

Detecting paroxysmal atrial fibrillation (pAF) soon after acute cerebral ischaemia has a major impact on secondary stroke prevention. Recently, the STAF score, a composite of clinical and instrumental findings, was introduced to identify stroke patients at risk of pAF. We aimed to validate this score in an independent study population.