Browsing by Author "Santo, G"
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- Familial Sneddon's syndromePublication . Mascarenhas, R; Santo, G; Ferro, MA; Tellechea, O; Gonçalo, Margarida; Figueiredo, AA syndrome associating Livedo Reticularis (LR) with Cerebrovascular disease (CVD) was described, in 1965, by Sneddon. It occurs sporadically, but a few familial cases of Sneddon's Syndrome (SS) have been reported, like these 3 cases that represent one of the largest number among siblings. We studied three male brothers, aged 28, 37 and 42 years, with CVD (ischaemic stroke in 2 patients and cerebral haemorrhages in the third) and their sister with no CVD. All patients presented with long lasting Livedo Reticularis, extending beyond the lower limbs. Skin biopsy on the centre of the reticular pattern showed, only in the second patient, partial endothelium detachment in dermo-hypodermic blood vessels. The males also had accesses of Livedoid Vasculitis (LV), in which a skin biopsy showed obliteration of several upper dermal vessels with hialin thrombi and a very scarce inflammatory infiltrate. Complementary studies, with an extensive investigation on pro-coagulation/pro-thrombotic features including antiphospholipid antibodies, were repeatedly negative. Their non-consanguineous parents were not affected, but among these kindred of 9 individuals, apart from the 4 patients reported above, LR and LV were present in two other brothers and also in an aunt and uncle, suggesting autosomal dominant pattern of inheritance, with incomplete penetrance. The relationship between Sneddon's Syndrome and Antiphospholipid Antibody Syndrome is controversial. The present cases, having repeatedly negative antiphospholipid antibodies, support the classification of Sneddon's Syndrome as an independent nosological entity.
- Pathophysiology of Blood–Brain Barrier Permeability Throughout the Different Stages of Ischemic Stroke and Its Implication on Hemorrhagic Transformation and RecoveryPublication . Bernardo-Castro, S; Sousa, JA; Brás, A; Cecília, C; Rodrigues, B; Almendra, L; Machado, C; Santo, G; Silva, F; Ferreira, L; Santana, I; Sargento-Freitas, JThe blood-brain barrier (BBB) is a dynamic interface responsible for maintaining the central nervous system homeostasis. Its unique characteristics allow protecting the brain from unwanted compounds, but its impairment is involved in a vast number of pathological conditions. Disruption of the BBB and increase in its permeability are key in the development of several neurological diseases and have been extensively studied in stroke. Ischemic stroke is the most prevalent type of stroke and is characterized by a myriad of pathological events triggered by an arterial occlusion that can eventually lead to fatal outcomes such as hemorrhagic transformation (HT). BBB permeability seems to follow a multiphasic pattern throughout the different stroke stages that have been associated with distinct biological substrates. In the hyperacute stage, sudden hypoxia damages the BBB, leading to cytotoxic edema and increased permeability; in the acute stage, the neuroinflammatory response aggravates the BBB injury, leading to higher permeability and a consequent risk of HT that can be motivated by reperfusion therapy; in the subacute stage (1-3 weeks), repair mechanisms take place, especially neoangiogenesis. Immature vessels show leaky BBB, but this permeability has been associated with improved clinical recovery. In the chronic stage (>6 weeks), an increase of BBB restoration factors leads the barrier to start decreasing its permeability. Nonetheless, permeability will persist to some degree several weeks after injury. Understanding the mechanisms behind BBB dysregulation and HT pathophysiology could potentially help guide acute stroke care decisions and the development of new therapeutic targets; however, effective translation into clinical practice is still lacking. In this review, we will address the different pathological and physiological repair mechanisms involved in BBB permeability through the different stages of ischemic stroke and their role in the development of HT and stroke recovery.