Mesut Yeniguen

Combined contrast-enhanced ultrasound and rt-PA treatment is safe and improves impaired microcirculation after reperfusion of middle cerebral artery occlusion.

In monitoring of recanalization and in sonothrombolysis, contrast-enhanced ultrasound (CEUS) is applied in extended time protocols. As extended use may increase the probability of unwanted effects, careful safety evaluation is required. We investigated the safety profile and beneficial effects of CEUS in a reperfusion model. Wistar rats were subjected to filament occlusion of the right middle cerebral artery (MCA). Reperfusion was established after 90 minutes, followed by recombinant tissue-type plasminogen activator (rt-PA) treatment and randomization to additional CEUS (contrast agent: SonoVue; 60 minutes). Blinded outcome evaluation consisted of magnetic resonance imaging (MRI), neurologic assessment, and histology and, in separate experiments, quantitative 3D nano-computed tomography (CT) angiography (900 nm3 voxel size). Nano-CT revealed severely compromised microcirculation in untreated animals after MCA reperfusion. The rt-PA partially improved hemispheric perfusion. Impairment was completely reversed in animals receiving rt-PA and CEUS. This combination was more effective than treatment with either CEUS without rt-PA or rt-PA and ultrasound or ultrasound alone. In MRI experiments, CEUS and rt-PA treatment resulted in a significantly reduced ischemic lesion volume and edema formation. No unwanted effects were detected on MRI, histology, and intracranial temperature assessment. This study shows that CEUS and rt-PA is safe in the situation of reperfusion and displays beneficial effects on the level of the microvasculature.

Cortisol awakening and stress response, personality and psychiatric profiles in patients with takotsubo cardiomyopathy

Objective Alterations in cortisol awakening and stress responses (CAR, CSR) are sensitive markers for the basal activity and responsiveness of the hypothalamus–pituitary–adrenal axis (HPAA) in psychopathological conditions. We investigated whether patients with takotsubo cardiomyopathy (TTC) differ in these markers when compared with non-ST-segment elevation myocardial infarction (NSTEMI) patients and healthy controls. Methods 19 female TTC patients were compared with 20 female NSTEMI patients and with 20 healthy women, matched by age and index event date. Salivary sampling indicated cortisol release, questionnaires assessed personality, life events, chronic stress and psychiatric symptoms. Results The groups did not differ relevantly in their basal HPAA activity, psychiatric or personality profiles. Despite increased heart rates in response to stress (median difference (MDdiff)=3.5, p=0.002) and higher nervousness scores (MDdiff=−3.0, p=0.024), TTC patients revealed a blunted CSR with a medium effect compared to the controls (MDdiff=−3.2 nmol/L, p=0.022, r=0.36); even when controlled for prestress cortisol differences (p=0.044, r=0.33). In comparison with NSTEMI patients, no significant differences in CSR (MDdiff=−1.9 nmol/L, p=0.127, r=0.25) or nervousness (MDdiff=2.0, p=0.107) can be observed. Stressful life events, for example, traumatic experiences, occurred more often in TTC (42%) than in NSTEMI patients and controls (both 10%, p=0.031). Conclusions In this small exploratory trial, a trend for a blunted CSR and high incidences of stressful life events were observed in TTC patients. If these results can be confirmed in larger studies, chronic stress and the inhibitory influence of cortisol on catecholamine release might be significant for the pathogenesis of TTC.

Evaluation of the middle cerebral artery occlusion techniques in the rat by in-vitro 3-dimensional micro- and nano computed tomography

BackgroundAnimal models of focal cerebral ischemia are widely used in stroke research. The purpose of our study was to evaluate and compare the cerebral macro- and microvascular architecture of rats in two different models of permanent middle cerebral artery occlusion using an innovative quantitative micro- and nano-CT imaging technique.Methods4h of middle cerebral artery occlusion was performed in rats using the macrosphere method or the suture technique. After contrast perfusion, brains were isolated and scanned en-bloc using micro-CT (8 μm)3 or nano-CT at 500 nm3 voxel size to generate 3D images of the cerebral vasculature. The arterial vascular volume fraction and gray scale attenuation was determined and the significance of differences in measurements was tested with analysis of variance [ANOVA].ResultsMicro-CT provided quantitative information on vascular morphology. Micro- and nano-CT proved to visualize and differentiate vascular occlusion territories performed in both models of cerebral ischemia. The suture technique leads to a remarkable decrease in the intravascular volume fraction of the middle cerebral artery perfusion territory. Blocking the medial cerebral artery with macrospheres, the vascular volume fraction of the involved hemisphere decreased significantly (p < 0.001), independently of the number of macrospheres, and was comparable to the suture method. We established gray scale measurements by which focal cerebral ischemia could be radiographically categorized (p < 0.001). Nano-CT imaging demonstrates collateral perfusion related to different occluded vessel territories after macrosphere perfusion.ConclusionMicro- and Nano-CT imaging is feasible for analysis and differentiation of different models of focal cerebral ischemia in rats.

Sonothrombolysis with BR38 Microbubbles Improves Microvascular Patency in a Rat Model of Stroke.

Background Early recanalization of large cerebral vessels in ischemic stroke is associated with improved clinical outcome, however persisting hypoperfusion leads to poor clinical recovery despite large vessel recanalization. Limited experimental sonothrombolysis studies have shown that addition of microbubbles during treatment can improve microvascular patency. We aimed to determine the effect of two different microbubble formulations on microvascular patency in a rat stroke model. Methods We tested BR38 and SonoVue® microbubble-enhanced sonothrombolysis in Wistar rats submitted to 90-minute filament occlusion of the middle cerebral artery. Rats were randomized to treatment (n = 6/group): control, rt-PA, or rt-PA+3-MHz ultrasound insonation with BR38 or SonoVue® at full or 1/3 dose. Treatment duration was 60 minutes, beginning after withdrawal of the filament, and sacrifice was immediately after treatment. Vascular volumes were evaluated with microcomputed tomography. Results Total vascular volume of the ipsilateral hemisphere was reduced in control and rt-PA groups (p<0.05), but was not significantly different from the contralateral hemisphere in all microbubble-treated groups (p>0.1). Conclusions Microbubble-enhanced sonothrombolysis improves microvascular patency. This effect is not dose- or microbubble formulation-dependent suggesting a class effect of microbubbles promoting microvascular reopening. This study demonstrates that microbubble-enhanced sonothrombolysis may be a therapeutic strategy for patients with persistent hypoperfusion of the ischemic territory.

Locus of control and stress management strategies in women with takotsubo cardiomyopathy.

The aetiology of takotsubo cardiomyopathy (TTC) is still poorlyunderstood. The most established theory of catecholamine-mediatedmyocardial stunning being provoked by a stressful event is supportedby supraphysiological levels of plasma catecholamines in TTC patients[1]. TTC predominantly occurs in postmenopausal women, and severalstudies suggest a predisposing role of psychiatric or personality traitsin its pathogenesis [2,3].In our recent study, female TTC patients were screened in detail forpsychosocialattributes,butourfindingslendsupportforneithernotice-able psychiatric or personality characteristics nor for an increasedoccurrence of social or work hassles. However, TTC patients showed ablunted cortisol stress response (CSR) compared with cardiac-healthycontrols and high incidences of stressful or traumatic life-events com-pared with healthy controls and non-ST-segment elevation myocardialinfarction (NSTEMI) patients [4].It issuggested thatcertainpersonalitytraits,suchaslocusof control(LOC), largely determine how people cope with stress. Internal LOCrefers to the conviction that outcomes of live events are determinedby ones own behaviour and choices, and is associated with a more ac-tive search for solutions to reduce stress. To the contrary, external LOCimpliesthatoutcomeisdeterminedbyluck,chance,orpowerfulothers.It is associated with unfavourable stress management strategies, leadsto higher stress levels, and might predispose to somatic illness [5].To our knowledge, LOC has not been investigated in TTC patients sofar, and only the research from Hefner and colleagues focuses on stressmanagement in these patients. In their retrospective study [6], the re-searchers compared 31 female TTC patients with 104 healthy womenfrom a normative control sample of the stress-coping questionnaire(SVF-120) and found TTC patients to use some positive strategies,such as deemphasising, less often than controls. In their second paper[7], the authors did not report differences in stress management whenthese TTC patients were compared with 30 females with a history ofacute coronary syndrome (ACS).The present hypothesis-generating study aims to identify internaland external LOC as a possible predisposing personality trait and its re-lationship to stress management in TTC patients for the first time, andcontrasts the results to those of NSTEMI patients and healthy controls.Data were collected from 19 female TTC patients diagnosed atKerckhoff Heart and Thorax Center, Bad Nauheim, Germany. Twentywomen with a history of NSTEMI and 20 cardiac-healthy female volun-teers served as controls. The groups were matched by age (mean age60.5 ± 9.2), and the TTC and NSTEMI patients were additionallymatched by their index event date in relation to study inclusion(mean months 18.4 ± 8.5). All participants gave written, informedconsent and have recently attended our previous study. For extensiveinformationaboutmethodological,clinicalandsociodemographicchar-acteristicspleaserefertothispublication[4].Thelocalethicscommitteeapproved the study.We used the German IPC questionnaire [8] to determine internal(I-Scale) and two dimensions of external LOC (P-scale = powerfulothers, C-scale = chance) which measure ones belief in ‘who’ has thecontroland‘howmuch’controlonehasoveroneslife.Theshortversionof the stress-coping questionnaire (SVF-78, [9]) investigates stressmanagement. It comprises 78 items divided into 13 subscales ofeffective or maladaptive strategies of coping with stress (Table 1).Behaviours defined in the subscales 2–5and8–10 are considered as

Flat-panel volumetric computed tomography in cerebral perfusion: evaluation of three rat stroke models.

Flat-panel volumetric computed tomography (fpVCT) is a non-invasive approach to three-dimensional small animal imaging. The capability of volumetric scanning and a high resolution in time and space enables whole organ perfusion studies. We aimed to assess feasibility and validity of fpVCT in cerebral perfusion measurement with impaired hemodynamics by evaluation of three well-established rat stroke models for temporary and permanent middle cerebral artery occlusion (MCAO). Male Wistar rats were randomly assigned to temporary (group I: suture model) and permanent (group II: suture model; III: macrosphere model) MCAO and to a control group. Perfusion scans with respect to cerebral blood flow (CBF) and volume (CBV) were performed 24h post intervention by fpVCT, using a Gantry rotation time of 1s and a total scanning time of 30s. Postmortem analysis included infarct-size calculation by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Infarct volumes did not differ significantly throughout intervention groups. After permanent MCAO, CBF significantly decreased in subcortical regions to 78.2% (group II, p=0.005) and 79.9% (group III, p=0.012) and in total hemisphere to 77.4% (group II, p=0.010) and 82.0% (group III, p=0.049). CBF was less impaired with temporary vessel occlusion. CBV measurement revealed no significant differences. Results demonstrate feasibility of cerebral perfusion quantification in rats with the fpVCT, which can be a useful tool for non-invasive dynamic imaging of cerebral perfusion in rodent stroke models. In addition to methodological advantages, CBF data confirm the macrosphere model as a useful alternative to the suture model for permanent experimental MCAO.

Psychosocial and psychoneuroendocrinal aspects of Takotsubo syndrome

Great advances have been made in our understanding of Takotsubo syndrome in the past decade, but the aetiology of the condition remains incompletely understood. The most established theory, that catecholamine-mediated myocardial stunning is provoked by emotional or physiological stress, is supported by the presence of supraphysiological levels of plasma catecholamines in patients with Takotsubo syndrome. For this reason, the hyperexcitability of the autonomic nervous system under conditions of physical and emotional stress is often assessed in these patients. Observational studies have indicated that a predisposing influence of chronic or traumatic stress, anxiodepressive disorders, and maladaptive personality traits are linked to the pathogenesis of Takotsubo syndrome. Chronic stress can influence autonomic function through dysregulation of the hypothalamic–pituitary–adrenal axis and contribute to the development of cardiovascular disorders. In this Perspectives article, we discuss the current knowledge of the psychoneuroendocrinological and psychosocial mechanisms underlying the pathophysiology of Takotsubo syndrome.

No evidence for CCVSI in relapsing-remitting multiple sclerosis patients with moderate disability.

Dear Sirs, The hypothesis of chronic cerebrospinal venous insufficiency (CCSVI) as a primary cause of multiple sclerosis (MS) has been recently introduced [8]. The CCSVI might provide an explanation for the topographical relation between cerebral veins and focal demyelinating lesions, a characteristic feature of MS. The CCSVI is defined as the presence of at least two out of five ultrasound criteria such as increased reflux from vertebral veins or deep cerebral veins [1, 8, 9]. The initial study on CCSVI in patients with relapsing-remitting and progressive MS with moderate to severe disability suggested that CCSVI occurs in up to 100 % of patients and that is not present in healthy controls at all [8]. There have been a number of attempts to reproduce these findings, some studies see a correlation between impaired venous outflow and MS [5, 10], in other studies there is no association at all [2, 3]. The CCSVI has not caused a major paradigm change for MS yet. The aim of the study was to test the hypothesis that CCSVI is present in a group of patients with relapsing-remitting MS moderately affected by the disease. The study was performed by an experienced team dedicated to cerebrovenous ultrasound. Twelve patients with relapsing-remitting MS (RRMS), who fulfilled the revised McDonald criteria [6], were recruited from the outpatient clinic. Thirteen healthy controls were recruited from accompanying spouses and friends. The cohort size was chosen to detect at least a 50 % difference in CCSVI frequency at a power of 80 %. Patient details are summarized in Table 1. The study was approved by the local ethics committee, all persons gave their informed consent prior to inclusion. Venous examination was carried out on an iU22 ultrasound system (Philips, Hamburg, Germany) using a linear transducer (9 to 4 MHz) for extracranialand a phased array transducer (5 to 1 MHz) for intracranial vessel examination. We used an examination protocol described earlier [4, 8]. Prior to entering the room by the sonographer, patients and controls were placed on the examination chair by a MS nurse and instructed not to talk to the sonographer. Sonographers were blinded to the group allocation. Frequencies were compared with a v or Fisher’s exact test respectively, continuous variables with a Mann–Whitney-U-Test. Results are summarized in Table 2. Neither patients nor controls fulfilled criteria for the final diagnosis of CCSVI with at least two positive ultrasound criteria. Only in a single control subject, evidence for proximal internal jugular vein (IJV) stenosis, defined as a reduction of crosssectional area (CSA) B0.3 cm in the supine position, was found (CSA 0.284 cm). There were no differences between patients and controls for any other criteria. The results of the study suggest that CCSVI, as defined above, is not present in patients moderately affected by relapsing-remitting MS. Limited by the number of subjects, this study does not rule out a small correlation between CCVSI and MS. The findings are in agreement with a number of rigorous studies [2, 3] arguing against a causal relationship. Nevertheless, data from ultrasound and magnetic resonance venography studies [5, 10] still support the concept of CCSVI in MS. The reasons for these controversial findings remain unclear. Possible explanations for varying study outcomes include operator qualifications or M. Juenemann (&) M. Yeniguen E. Stolz M. Berghoff Department of Neurology, University of Giessen, Klinikstrasse 33, 35385 Giessen, Germany e-mail: martin.juenemann@neuro.med.uni-giessen.de