Cerebral Blood Volume Affects Blood–Brain Barrier Integrity in an Acute Transient Stroke Model

Abstract

Insufficient vascular reserve after an ischemic stroke may induce biochemical cascades that subsequently deteriorate the blood-brain barrier (BBB) function. However, the direct relationship between poor cerebral blood volume (CBV) restoration and BBB disruption has not been examined in acute stroke. To quantify BBB integrity at acute stages of transient stroke, in particular for cases in which extravasation of the standard contrast agent (Gd-DTPA) is not observed, we adopted the water exchange index (WEI), a novel magnetic resonance image-derived parameter to estimate the water permeability across the BBB. The apparent diffusion coefficient (ADC) and R 2 relaxation rate constant were also measured for outlining the tissue abnormality, while fractional CBV and WEI were quantified for assessing vascular alterations. The significantly decreased ADC and R 2 in the ischemic cortices did not correlate with the changes in CBV or WEI. In contrast, a strong negative correlation between the ipsilesional WEI and CBV was found, in which stroke mice were clustered into two groups: (1) high WEI and low CBV and (2) normal WEI and CBV. The low CBV observed for mice with a disrupted BBB, characterized by a high WEI, indicates the importance of CBV restoration for maintaining BBB stability in acute stroke.

Simultaneous evaluation of vascular morphology, blood volume and transvascular permeability using SPION-based, dual-contrast MRI: imaging optimization and feasibility test

“…For example, Huang et al . demonstrated that the degree of CBV restoration significantly affects the blood–brain barrier integrity in an acute transient stroke model. In addition to its application to ischemia, our method can also be used to evaluate the activity of tumor angiogenesis and to monitor the effect of antiangiogenic treatment, as the BV and transvascular permeability are important parameters for evaluating angiogenesis .…”

“…Transvascular permeability was quantified by calculating the WEI . Assuming no exchange of CA between intravascular and extravascular compartments, the apparent fractional BV () can be calculated as follows : …”

“…Multiple gradient echo imaging was performed to measure SPION-induced ΔR 2 * with the following parameters: T R 300 ms; 10 T E values (6.39-59.15 ms; ΔT E 5.85); FA 60°; number of slices 15; number of averages 1; field of view 5 × 5 cm 2 ; slice thickness 2 mm. Transvascular permeability was quantified by calculating the WEI (2,17). Assuming no exchange of CA between intravascular and extravascular compartments, the apparent fractional BV (V α app ) can be calculated as follows (17):…”

Neuronal Effects of Sugammadex in combination with Rocuronium or Vecuronium

“…ROC, VEC or SUG cannot pass through a healthy and mature blood-brain barrier (BBB) 37,38. However, there is evidence that patients with an impaired BBB function treated with either of these compounds, present autonomic dysfunction, seizures 39 and neuronal cell death 15.…”

Estudo das lesões hiperdensas em tomografias computadorizadas de crânio de pacientes submetidos a tratamento endovascular para o acidente vascular cerebral isquêmico agudo

“…Todavia, pouco se sabe a relação das áreas apresentando captação de contraste na tomografia pós-tratamento endovascular e a área cerebral infartada final. Sugere-se que a captação de contraste ocorra em cérebro que já sofreu danos irreversíveis da isquemia e com isto houve quebra da barreira hematoencefálica (BHE) e lesão da lâmina basal (HUANG et al, 2013). Nos pacientes que receberam trombolítico, a lesão da BHE é mais intensa (DIJKHUIZEN et al, 2002).…”