Using the Reduced Uterine Perfusion Pressure model of preeclampsia to study the blood brain barrier permeability / Uso do modelo de Redução da Pressão de Perfusão Uterina de pré-eclâmpsia para estudar a permeabilidade da barreira hematoencefálica

AIMS: To use the Reduced Uterine Perfusion Pressure (RUPP) model for preeclampsia to describe and evaluate the blood brain barrier permeability in pregnant rats. METHODS: Forty-one pregnant Wistar rats were divided into different intervention groups between 13 to 15 days of gestation: PregnantControl (PC; n=12), Reduced Uterine Perfusion Pressure (RUPP; n=15), Invasive Blood Pressure-Control (IBP; n=7) and Reduced Uterine Perfusion Pressure and Invasive Blood Pressure (RUPP-IBP; n=7). The 14 rats of groups IBP and RUPP-IBP had their mean arterial pressure measured at day 21. All animals were then sacrificed, administered Evans Blue dye through the tail vein and perfused with paraformaldehyde 4%. Brains were removed and evaluated by a blinded pathologist. Results are presented as means and standard errors. Comparisons between the groups were performed using Student's t-test for continuous variables and Fisher's exact test for categorical variables. Statistical significance was set as a p value less than 0.05. RESULTS: Mean arterial pressure averaged 85.4±2.2 mmHg in the IPB group and 102.5±8.3 mmHg in the RUPP-IPB group (p=0.002). Among all the RUPP rats (RUPP and RUPP-IBP groups), 82% had a positive staining with Evans Blue dye for at least one of the brain hemispheres, while none of the pregnant control rats (PC and IBP groups) had brain staining (p<0.001). CONCLUSIONS: In this study, altered permeability of the blood brain barrier was successfully reproduced in pregnant rats exposed to the RUPP protocol. Therefore, we concluded that the RUPP model is a valid surrogate to study blood brain barrier abnormalities.

OBJETIVOS: Usar o modelo de Redução da Pressão de Perfusão Uterina / Reduced Uterine Perfusion Pressure (RUPP) de pré-eclâmpsia para descrever e avaliar a permeabilidade da barreira hematoencefálica. MÉTODOS: Quarenta e uma ratas Wistar prenhes foram estratificadas em diferentes grupos de intervenção entre 13 a 15 dias de gestação: grupo controle (PC; n=12), grupo modelo de redução da pressão de perfusão uterina (RUPP; n=15), grupo monitorização invasiva da pressão arterial (IBP; n=7) e grupo redução da pressão de perfusão uterina e monitorização invasiva da pressão arterial (RUPP-IBP; n=7). As 14 ratas dos grupos IBP e RUPP-IBP tiveram sua pressão arterial média aferida no dia 21. Logo após todos os animais foram sacrificados e foi administrado o corante Azul de Evans pela veia da cauda, seguido de formaldeído 4%. Os cérebros foram removidos e avaliados por um patologista cegado para os grupos. Os resultados são apresentados em médias e erros padrão. As comparações entre os grupos foram realizadas utilizando o teste t de Student para variáveis contínuas e o teste exato de Fisher para variáveis categóricas. A significância estatística foi definida como um valor de p inferior a 0,05. RESULTADOS: As médias e desvios padrões da pressão arterial média foram 85,4±2,2 mmHg no grupo IPB e 102,5±8,3 mmHg no grupo RUPP-IPB (p=0,002). Entre todas as ratas RUPP (grupos RUPP e RUPP-IBP), 82% tiveram marcação positiva pelo corante em pelo menos um dos hemisférios cerebrais, enquanto nenhuma das ratas controle (grupos PC e IBP) teve marcação cerebral positiva (p<0,001). CONCLUSÕES: Neste estudo, a permeabilidade alterada da barreira hematoencefálica foi reproduzida com sucesso em ratas prenhes expostas ao protocolo RUPP. Portanto, concluímos que o modelo RUPP é um substituto válido para estudar anormalidades da barreira hematoencefálica.

Cardioembolic sources in stroke patients in South of Brazil.

Background. Stroke is a leading cause of mortality and disability in Brazil and around the world. Cardioembolism is responsible for nearly 30% of the origins of ischemic stroke. Methods. We analyzed data of 256 patients with cardioembolic ischemic stroke (according to TOAST classification) who were admitted into the Hospital São Lucas-PUCRS from October 2011 to January 2014. The cardioembolic subtype was divided into six subgroups: arrhythmias, valvular heart disease, coronary artery disease, cardiomyopathy, septal abnormalities, and intracardiac injuries. The prevalence of the most important cardiovascular risk factors and medications in use for prevention of systemic embolism by the time of hospital admission was analyzed in each patient. Results. Among 256 patients aged 60.2 +/- 6.9 years, 132 males, arrhythmias were the most common cause of cardioembolism corresponding to 50.7%, followed by valvular heart disease (17.5%) and coronary artery disease (16%). Hypertension (61.7%) and dyslipidemia (43.7%) were the most common risk factors. Less than 50% of patients with arrhythmias were using oral anticoagulants. Conclusions. Identifying the prevalence of cardioembolic stroke sources subgroups has become an increasingly important role since the introduction of new oral anticoagulants. In this study, arrhythmias (especially atrial fibrillation) were the main cause of cardioembolism.

Blood-brain barrier breakdown in reduced uterine perfusion pressure: a possible model of posterior reversible encephalopathy syndrome.

BACKGROUND: Posterior reversible encephalopathy syndrome (PRES) is a clinical entity characterized by headaches, altered mental status, seizures, and visual disturbances and is associated with white matter vasogenic edema. There are no experimental models to study PRES brain changes. METHODS: Twenty-eight pregnant Wistar rats were divided into 4 groups of 7: (1) pregnant-control; (2) reduced uterine perfusion pressure (RUPP); (3) invasive blood pressure (IBP); and (4) reduced uterine perfusion pressure plus invasive blood pressure (RUPP-IBP). The RUPP and RUPP-IBP groups were submitted to a reduction of uterine perfusion pressure at pregnancy days 13 to 15. The invasive mean arterial pressure of the IBP and RUPP-IBP groups was measured on day 20. The blood-brain barriers (BBBs) of all groups were analyzed using 2% Evans Blue dye on day 21. RESULTS: RUPP rats had higher blood pressures and increased BBB permeability to Evans Blue dye compared with the control animals. Brain staining occurred in 11 of 14 RUPP rats and in none of the control groups (P < .0001). CONCLUSIONS: The physiopathology of PRES remains unclear. Here, we described the use of RUPP rats as a potential model to better comprehend this syndrome.

Posterior reversible encephalopathy syndrome following a scorpion sting.

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity not yet understood, that is present with transient neurologic symptoms and particular radiological findings. The most common imaging pattern in PRES is the presence of edema in the white matter of the posterior portions of both cerebral hemispheres. The cause of PRES is unclear. We report a case of 13-year-old male who was stung by a scorpion and developed a severe headache, visual disturbance, and seizures and had the diagnosis of PRES with a good outcome. Numerous factors can trigger this syndrome, most commonly: acute elevation of blood pressure, abnormal renal function, and immunosuppressive therapy. There are many cases described showing the relationship between PRES and eclampsia, transplantation, neoplasia and chemotherapy treatment, systemic infections, renal disease acute, or chronic. However, this is the first case of PRES following a scorpion sting.

Posterior Reversible Encephalopathy Syndrome Associated with FOLFOX Chemotherapy.

Posterior reversible encephalopathy syndrome (PRES) is a clinicoradiologic entity characterized by headaches, altered mental status, seizures, visual loss, and characteristic imaging pattern in brain MRI. The cause of PRES is not yet understood. We report a case of a 27-year-old woman that developed PRES after the use of FOLFOX 5 (oxaliplatin/5-Fluoracil/Leucovorin) chemotherapy for a colorectal cancer.

Risk factors among stroke subtypes in Brazil.

Stroke is a leading cause of mortality and disability in Brazil. Among the risk factors for cerebrovascular disease, some have more influence than others in certain stroke subtypes. Little data are available in the literature on the prevalence of stroke subtypes in Latin America. We analyzed data from 688 patients with acute ischemic stroke (52.3% women; mean age, 65.7 years) who were enrolled in a stroke data bank. Standardized data assessment and stroke subtype classification were used. The most common stroke subtype was large-artery atherosclerosis (n = 223; 32.4%), followed by cardioembolism (n = 195; 28.3%), and microangiopathy (n = 127; 18.5%). Stroke risk factors differ among stroke subtypes. The population of South America is ethnically diverse, and few previous studies have describe the distribution of risk factors among stroke subtypes in this population. In this study, the most important risk factors were hypertension and dyslipidemia.