Proenkephalin as marker for severity of aneurysmal subarachnoid hemorrhage: a pilot study

Objective: Several biomarker have shown associations with severity, vasospasm, ischemic events or outcome in aneurysmal subarachnoid hemorrhage. Yet no biomarker is used in daily clinical routine. Previously encephalin peptides were described as new biomarkers in ischemic stroke and traumatic brain injury. We sought to evaluate the usefulness of Proenkephalin A, a precursor protein of encephalin peptides, as biomarker in aneurysmal subarachnoid hemorrhage. Method: Eighteen consecutive patients with aSAH had plasma PENK A levels measured with a validated chemiluminescence sandwich immunoassay. The association of PENK A levels at admission with severity of SAH according to the World Federation of Neurological Surgeons (WFNS) grade after resuscitation was the primary endpoint. Levels of PENK A are analyzed with respect to different clinical and radiological scores as well as between patients with ICH, intraventricular hemorrhage, hydrocephalus, brain edema, vasospasm and ischemia. Results: Good grade patients showed median PENK A levels of 73.9pmol/l (IQR 69-80.4) and poor grade patients 117pmol/l (IQR 86-149). PENK A levels are significantly associated with severity of SAH as graded on the WFNS scale (p=0.03). No other parameter had a significant association. Conclusions: PENK A might be a useful serum marker in aSAH. Yet, larger trials also with serial PENK A assessments are needed.

Normal platelet activation profile in patients with peripheral arterial disease on aspirin.

BACKGROUND Peripheral arterial disease (PAD) is a progressive vascular disease associated with a high risk of cardiovascular morbidity and death. Antithrombotic prevention is usually applied by prescribing the antiplatelet agent aspirin. However, in patients with PAD aspirin fails to provide protection against myocardial infarction and death, only reducing the risk of ischemic stroke. Platelets may play a role in disease development, but this has not been tested by proper mechanistic studies. In the present study, we performed a systematic evaluation of platelet reactivity in whole blood from patients with PAD using two high-throughput assays, i.e. multi-agonist testing of platelet activation by flow cytometry and multi-parameter testing of thrombus formation on spotted microarrays. METHODS Blood was obtained from 40 patients (38 on aspirin) with PAD in majority class IIa/IIb and from 40 age-matched control subjects. Whole-blood flow cytometry and multiparameter thrombus formation under high-shear flow conditions were determined using recently developed and validated assays. RESULTS Flow cytometry of whole blood samples from aspirin-treated patients demonstrated unchanged high platelet responsiveness towards ADP, slightly elevated responsiveness after glycoprotein VI stimulation, and decreased responsiveness after PAR1 thrombin receptor stimulation, compared to the control subjects. Most parameters of thrombus formation under flow were similarly high for the patient and control groups. However, in vitro aspirin treatment caused a marked reduction in thrombus formation, especially on collagen surfaces. When compared per subject, markers of ADP- and collagen-induced integrin activation (flow cytometry) strongly correlated with parameters of collagen-dependent thrombus formation under flow, indicative of a common, subject-dependent regulation of both processes. CONCLUSION Despite of the use of aspirin, most platelet activation properties were in the normal range in whole-blood from class II PAD patients. These data underline the need for more effective antithrombotic pharmacoprotection in PAD.

Fluorescence lifetime imaging in retinal artery occlusion.

PURPOSE Fluorescence lifetime imaging ophthalmoscopy is a technique to measure decay times of endogenous retinal fluorophores. The purpose of this study was to investigate fluorescence lifetimes in eyes with central and branch retinal artery occlusion. METHODS Twenty-four patients with central or branch retinal artery occlusion were included in this study. The contralateral unaffected fellow eye was used as control. Measurements were performed using a fluorescence lifetime imaging ophthalmoscope based on a HRA Spectralis system. Fluorescence excitation wavelength was 473 nm, and mean lifetimes were measured in a short (498-560 nm) and in a long (560-720 nm) spectral channel. Fluorescence lifetimes in the area of retinal artery occlusion were measured and compared to corresponding areas in contralateral unaffected eyes. Additionally, findings were correlated to optical coherence tomography measurements. RESULTS Retinal lifetime images of 24 patients with retinal artery occlusion were analyzed. Mean retinal fluorescence lifetimes were prolonged by 50% in the short and 20% in the long spectral channel in ischemic retinal areas up to 3 days after retinal artery occlusion compared to the contralateral unaffected eyes. In the postacute disease stage there was no difference between the lifetimes of affected areas and unaffected fellow eyes. CONCLUSIONS Retinal artery occlusion leads to significantly longer fluorescence lifetimes of the retina in the acute phase and may serve as a useful indicator for acute ischemic retinal damage.

Initiation of rivaroxaban in patients with nonvalvular atrial fibrillation at the primary care level:: The Swiss Therapy in Atrial Fibrillation for the Regulation of Coagulation (STAR) Study.

BACKGROUND Rivaroxaban has become an alternative to vitamin-K antagonists (VKA) for stroke prevention in non-valvular atrial fibrillation (AF) patients due to its favourable risk-benefit profile in the restrictive setting of a large randomized trial. However in the primary care setting, physician's motivation to begin with rivaroxaban, treatment satisfaction and the clinical event rate after the initiation of rivaroxaban are not known. METHODS Prospective data collection by 115 primary care physicians in Switzerland on consecutive nonvalvular AF patients with newly established rivaroxaban anticoagulation with 3-month follow-up. RESULTS We enrolled 537 patients (73±11years, 57% men) with mean CHADS2 and HAS-BLED-scores of 2.2±1.3 and 2.4±1.1, respectively: 301(56%) were switched from VKA to rivaroxaban (STR-group) and 236(44%) were VKA-naïve (VN-group). Absence of routine coagulation monitoring (68%) and fixed-dose once-daily treatment (58%) were the most frequent criteria for physicians to initiate rivaroxaban. In the STR-group, patient's satisfaction increased from 3.6±1.4 under VKA to 5.5±0.8 points (P<0.001), and overall physician satisfaction from 3.9±1.3 to 5.4±0.9 points (P<0.001) at 3months of rivaroxaban therapy (score from 1 to 6 with higher scores indicating greater satisfaction). In the VN-group, both patient's (5.4±0.9) and physician's satisfaction (5.5±0.7) at follow-up were comparable to the STR-group. During follow-up, 1(0.19%; 95%CI, 0.01-1.03%) ischemic stroke, 2(0.37%; 95%CI, 0.05-1.34%) major non-fatal bleeding and 11(2.05%; 95%CI, 1.03-3.64%) minor bleeding complications occurred. Rivaroxaban was stopped in 30(5.6%) patients, with side effects being the most frequent reason. CONCLUSION Initiation of rivaroxaban for patients with nonvalvular AF by primary care physicians was associated with a low clinical event rate and with high overall patient's and physician's satisfaction.

Non-canonical actions of Nogo-A and its receptors

Nogo-A is a myelin associated protein and one of the most potent neurite growth inhibitors in the central nervous system. Interference with Nogo-A signaling has thus been investigated as therapeutic target to promote functional recovery in CNS injuries. Still, the finding that Nogo-A presents a fairly ubiquitous expression in many types of neurons in different brain regions, in the eye and even in the inner ear suggests for further functions besides the neurite growth repression. Indeed, a growing number of studies identified a variety of functions including regulation of neuronal stem cells, modulation of microglial activity, inhibition of angiogenesis and interference with memory formation. Aim of the present commentary is to draw attention on these less well-known and sometimes controversial roles of Nogo-A. Furthermore, we are addressing the role of Nogo-A in neuropathological conditions such as ischemic stroke, schizophrenia and neurodegenerative diseases.

Factor H variant Y402H and the prevalence of hypertension and proteinuria: The Atherosclerosis Risk in Communities study

Hypertension is a significant risk factor for cardiovascular disease, which in turn is a major cause of morbidity and mortality worldwide. While the pathogenesis of vascular injury and subsequent end organ damage is complex, there is emerging data to support a role for the complement system in endovascular diseases. The complement Factor H Y402H polymorphism has been associated with a number of vasculopathies, including age-related macular degeneration (AMD), ischemic stroke and myocardial infarction. The current study evaluated the relationship of the Y402H polymorphism with hypertension and microalbuminuria in large the bi-racial Atherosclerosis Risk in Communities (ARIC) study. The Y402H polymorphism was found to be associated with a 48% (p-value 0.042) increase in the risk of developing incident hypertension in African American participants. No significant association was found with the Y402H polymorphism and microalbuminuria. The results from this investigation reveal the first association of the Factor H Y402H polymorphism and an increased risk of incident hypertension in African Americans. ^

Safety, feasibility, and long-term results of percutaneous closure of atrial septal defects using the Amplatzer septal occluder without periprocedural echocardiography.

OBJECTIVES We sought to assess the safety and efficacy of percutaneous closure of atrial septal defects (ASDs) under fluoroscopic guidance only, without periprocedural echocardiographic guidance. BACKGROUND Percutaneous closure of ASDs is usually performed using simultaneous fluoroscopic and transthoracic, transesophageal (TEE), or intracardiac echocardiographic (ICE) guidance. However, TEE requires deep sedation or general anesthesia, which considerably lengthens the procedure. TEE and ICE increase costs. METHODS Between 1997 and 2008, a total of 217 consecutive patients (age, 38 ± 22 years; 155 females and 62 males), of whom 44 were children ≤16 years, underwent percutaneous ASD closure with an Amplatzer ASD occluder (AASDO). TEE guidance and general anesthesia were restricted to the children, while devices were implanted under fluoroscopic guidance only in the adults. For comparison of technical safety and feasibility of the procedure without echocardiographic guidance, the children served as a control group. RESULTS The implantation procedure was successful in all but 3 patients (1 child and 2 adults; 1.4%). Mean device size was 23 ± 8 mm (range, 4-40 mm). There was 1 postprocedural complication (0.5%; transient perimyocarditis in an adult patient). At last echocardiographic follow-up, 13 ± 23 months after the procedure, 90% of patients had no residual shunt, whereas a minimal, moderate, or large shunt persisted in 7%, 1%, and 2%, respectively. Four adult patients (2%) underwent implantation of a second device for a residual shunt. During a mean follow-up period of 3 ± 2 years, 2 deaths and 1 ischemic stroke occurred. CONCLUSION According to these results, percutaneous ASD closure using the AASDO without periprocedural echocardiographic guidance seems safe and feasible.

Intracerebral tumor-associated hemorrhage caused by overexpression of the vascular endothelial growth factor isoforms VEGF121 and VEGF165 but not VEGF189

The vascular endothelial growth factor (VEGF) has been shown to be a significant mediator of angiogenesis during a variety of normal and pathological processes, including tumor development. Human U87MG glioblastoma cells express the three VEGF isoforms: VEGF121, VEGF165, and VEGF189. Here, we have investigated whether these three isoforms have distinct roles in glioblastoma angiogenesis. Clones that overexpressed each isoform were derived and inoculated into mouse brains. Mice that received VEGF121- and VEGF165-overexpressing cells developed intracerebral hemorrhages after 60–90 hr. In contrast, mice implanted with VEGF189-overexpressing cells had only slightly larger tumors than those caused by parental cells and little evidence of hemorrhage at these early times after implantation, whereas, after longer periods of growth, enhanced angiogenicity and tumorigenicity were apparent. There was rapid blood vessel growth and breakdown around the tumors caused by cells overexpressing VEGF121 and VEGF165, whereas there was similar vascularization but no eruption in the vicinity of those tumors caused by cells overexpressing VEGF189, and none on the border of the tumors caused by the parental cells. Thus, by introducing VEGF-overexpressing glioblastoma cells into the brain, we have established a reproducible and predictable in vivo model of tumor-associated intracerebral hemorrhage caused by the enhanced expression of single molecular species. Such a model should be useful for uncovering the role of VEGF isoforms in the mechanisms of angiogenesis and for investigating intracerebral hemorrhage due to ischemic stroke or congenital malformations.

Tetracyclines inhibit microglial activation and are neuroprotective in global brain ischemia

Ischemic stroke is the most common life-threatening neurological disease and has limited therapeutic options. One component of ischemic neuronal death is inflammation. Here we show that doxycycline and minocycline, which are broad-spectrum antibiotics and have antiinflammatory effects independent of their antimicrobial activity, protect hippocampal neurons against global ischemia in gerbils. Minocycline increased the survival of CA1 pyramidal neurons from 10.5% to 77% when the treatment was started 12 h before ischemia and to 71% when the treatment was started 30 min after ischemia. The survival with corresponding pre- and posttreatment with doxycycline was 57% and 47%, respectively. Minocycline prevented completely the ischemia-induced activation of microglia and the appearance of NADPH-diaphorase reactive cells, but did not affect induction of glial acidic fibrillary protein, a marker of astrogliosis. Minocycline treatment for 4 days resulted in a 70% reduction in mRNA induction of interleukin-1β-converting enzyme, a caspase that is induced in microglia after ischemia. Likewise, expression of inducible nitric oxide synthase mRNA was attenuated by 30% in minocycline-treated animals. Our results suggest that lipid-soluble tetracyclines, doxycycline and minocycline, inhibit inflammation and are neuroprotective against ischemic stroke, even when administered after the insult. Tetracycline derivatives may have a potential use also as antiischemic compounds in humans.

An N-methyl-d-aspartate receptor channel blocker with neuroprotective activity

Excitotoxicity, resulting from sustained activation of glutamate receptors of the N-methyl-d-aspartate (NMDA) subtype, is considered to play a causative role in the etiology of ischemic stroke and several neurodegenerative diseases. The NMDA receptor is therefore a target for the development of neuroprotective agents. Here, we identify an N-benzylated triamine (denoted as NBTA) as a highly selective and potent NMDA-receptor channel blocker selected by screening a reduced dipeptidomimetic synthetic combinatorial library. NBTA blocks recombinant NMDA receptors expressed in Xenopus laevis oocytes with a mean IC50 of 80 nM; in contrast, it does not block GluR1, a glutamate receptor of the non-NMDA subtype. The blocking activity of NBTA on NMDA receptors exhibits the characteristics of an open-channel blocker: (i) no competition with agonists, (ii) voltage dependence, and (iii) use dependence. Significantly, NBTA protects rodent hippocampal neurons from NMDA receptor, but not kainate receptor-mediated excitotoxic cell death, in agreement with its selective action on the corresponding recombinant receptors. Mutagenesis data indicate that the N site, a key asparagine on the M2 transmembrane segment of the NR1 subunit, is the main determinant of the blocker action. The results highlight the potential of this compound as a neuroprotectant.

Prognóstico de acidentes neurológicos transitórios com sintomas atípicos

Trabalho Final do Curso de Mestrado Integrado em Medicina, Faculdade de Medicina, Universidade de Lisboa, 2014

Disfagia no doente com AVC : prevalência e determinantes

Introdução: O acidente vascular cerebral (AVC) assume em Portugal elevadas taxas de morbilidade e reinternamento hospitalar. A disfagia surge como uma complicação frequente deste evento neurológico, com índices de morbilidade elevados pelo risco de desnutrição, desidratação e aspiração broncopulmonar. O diagnóstico e a sua monitorização no processo de reabilitação do doente são ações fundamentais na prevenção de aspirações alimentares, redução do internamento hospitalar e na eficácia da reabilitação do doente. Objetivo: Identificar e avaliar o grau de disfagia na pessoa com AVC e analisar a relação entre esta, e as variáveis socio-demográficas e clínicas no sentido de poder melhorar futuramente os cuidados de enfermagem de reabilitação. Métodos: Trata-se de um estudo não experimental, transversal, descritivo-correlacional de caráter quantitativo, que foi realizado numa amostra não probabilística por conveniência, constituída por 25 doentes com diagnóstico de AVC, internados na Rede Nacional Cuidados Continuados Integrados (RNCCI), em unidades de Convalescença e Reabilitação. O instrumento de colheita de dados integra uma seção de caracterização sócio-demográfica e clínica e duas escalas: Escala Gugging Swallowing Screen (GUSS) e Índice de Barthel, a fim de avaliar a disfagia e a funcionalidade, respetivamente. Resultados: A amostra apresenta uma média de idade de 76,8 anos, sendo 68% do sexo feminino e 32% do sexo masculino. Verificámos que 68% dos participantes apresenta mais de dois antecedentes clínicos e apenas 24% dos participantes não apresenta disfagia. Dos restantes, 12% apresenta disfagia grave, 36% moderada e 28% disfagia ligeira. A área de lesão parece influenciar a deglutição, demonstrando a Artéria Cerebral Média (ACM) e Artéria Cerebral Posterior (ACP) como áreas de maior sensibilidade. Denotou-se que quanto maior o grau de dependência, maior gravidade de disfagia. Conclusão: Doentes com AVC isquémico apresentam disfagia, com gravidade relacionada com a área vascular. A existência de vários antecedentes clínicos pode gerar perturbações na deglutição do doente. De igual modo, quanto maior for a dependência funcional do doente, maior é o grau de disfagia e o risco de aspiração pulmonar. Palavras-chave: AVC; Disfagia; Reabilitação.

Determinantes da incapacidade funcional em doentes com AVC

Introdução- O Acidente Vascular Cerebral continua a ser a primeira causa de morte em Portugal, sendo também responsável pelo elevado índice de incapacidade e dependência funcional da população adulta portuguesa, afetando significativamente os aspetos da vida física, económica e social. Os processos de reabilitação continuados têm-se mostrado bastante eficazes na recuperação da independência funcional destes doentes. Assim sendo o objetivo geral deste estudo consiste em avaliar o nível de independência funcional e os fatores determinantes nesses níveis, em doentes sujeitos a programas de reabilitação continuados e doentes sem reabilitação. Métodos- O presente estudo é de carácter quantitativo, enquadrando-se num desenho de estudo descritivo transversal e analítico, no qual participaram 60 indivíduos que sofreram AVC, pertencendo 36 ao grupo experimental e 24 ao grupo de controle. A recolha de dados foi efetuada através de um questionário composto por questões de caracterização sociodemográfica, de caracterização clinica, uma escala de APGAR Familiar e uma Escala de Medida de Independência funcional (MIF). Resultados- A análise por grupos mostra que o grupo experimental é mais independente que o grupo de controle, ou seja, o nível de independência funcional é mais elevado na sua generalidade na amostra de indivíduos sujeitos a processos de reabilitação. As variáveis que influenciaram significativamente a independência funcional foram: o género (no comportamento social no G.cont),o estado civil (solteiros/viúvo mais independentes aos níveis dos cuidados pessoais, controle dos esfíncteres, mobilidade e locomoção no G. exp), habilitações académicas (maior escolaridade maior independência no G. exp) fatores de risco (doentes sem fatores de risco no G. cont são mais independentes nos cuidados pessoais, controle de esfíncteres e locomoção), indivíduos com AVC isquémico são mais independentes nos cuidados pessoais e locomoção, e os que realizaram trombólise são mais independentes nas diferentes dimensões nos dois grupos. Conclusão- As variáveis sociodemográficas e clinicas exercem influência apenas em algumas dimensões da independência funcional dos utentes após o AVC e a reabilitação desenvolvida de forma continuada, aumenta o grau de independência dos doentes diminuindo o grau de incapacidade. Palavras-chave- Acidente Vascular Cerebral, Incapacidade, Independência Funcional, Reabilitação.

Ganhos em independência funcional no doente com AVC

Introdução – O Acidente Vascular Cerebral (AVC) representa a principal causa de dependência funcional da população adulta portuguesa. Conhecer os fatores que possam aumentar os ganhos em independência funcional é crucial para uma melhoria na abordagem destes doentes. Objetivo – Analisar os ganhos em independência funcional no doente que sofreu AVC considerando a diferença no Índice de Barthel entre a admissão e a alta e desde a alta até à primeira consulta. Métodos – Estudo de coorte retrospetivo, utilizando a base de dados hospitalar para doentes admitidos numa unidade de AVC entre 2010 e 2014. O Índice de Barthel (IB) na admissão, alta e primeira consulta após alta foi usado para calcular ganhos em independência funcional por dia entre a admissão e a alta (diferença entre IB na alta e na admissão dividindo pelo número de dias de internamento) e por semana entre a alta e a primeira consulta (diferença entre IB na primeira consulta e na alta dividindo pelo número de semanas entre a alta e a consulta). Com modelos de regressão linear avaliou-se a influência de fatores demográficos, clínicos e o destino após a alta nos ganhos em independência funcional por dia e por semana, obtendo-se coeficientes de regressão e respetivo intervalo de confiança a 95% (IC95%). Resultados – Nos 483 doentes estudados, a idade mediana é 76 anos, 59,0% são homens, 84,3% têm AVC isquémico e 30,6% foram para o domicílio após a alta. A independência funcional por dia aumentou nos anos mais recentes, particularmente em 2013 em que este parâmetro aumentou 1,164 pontos (com IC95%: 0,192 e 2,135; p=0,019) em comparação com 2010. Também o diagnóstico influenciou os ganhos diários em independência funcional, com LACI e PACI apresentando um aumento estatisticamente significativo de 1,372 pontos (IC95%: 0,324 e 2,421; p=0,010) e de 1,275 pontos (IC95%: 0,037 e 2,514; p=0,044), respetivamente, em comparação com POCI. Relativamente à independência funcional por semana, idades mais avançada e score elevado do IB na alta estão associados a menos ganhos por semana (p<0,001 e p=0,002). Também o destino após alta influencia os ganhos por semana, doentes encaminhados para unidades de convalescença apresentam ganhos de 1,289 pontos (IC95%: 0,661 e 1,917; p<0,001) em comparação com os doentes que foram para o domicílio. iv Conclusões – Houve melhoria na evolução funcional entre a admissão e a alta dos doentes em anos mais recentes sugerindo melhorias nas unidades de AVC. Atenção particular deve ser dada a estes doentes após a alta, particularmente nos de idade mais avançada.