Photodynamic therapy of brain tumors and novel optical coherence tomography strategies for in vivo monitoring of cerebral°uid dynamics

Photodynamic therapy(PDT)is a promising tool for least-invasive alternative methods for the treatment of brain tumors.The newly discovered PDT-induced opening of the blood–brain barrier(BBB)permeability open novel strategies for drug-brain delivery during post-surgical treatment of glioblastoma GBM.Here we discuss mechanisms of PDT-mediated opening of the BBB and age differences in PDT-related increase in BBB permeability,including with formation of brain edema.The meningeal lymphatic system plays a crucial role in the mechanism of brain drainage and clearance from metabolites and toxic molecules.We discuss that noninvasive photonic stimulation of°uid clearance via meningeal lymphatic vessels,and application of optical coherence tomography(OCT)for bed-side monitoring of meningeal lymphatic drainage has the promising perspective to be widely applied in both experimental and clinical studies of PDT and improving guidelines of PDT of brain tumors.

Laser speckle imaging and wavelet analysis of cerebral blood flow associated with the opening of the blood–brain barrier by sound

The cerebral blood flow（CBF） alterations related to sound-induced opening of the blood–brain barrier（BBB） in adult mice are studied using laser speckle contrast imaging（LSCI） and wavelet analysis of vascular physiology.The results clearly show that the opening of the BBB is accompanied by the changes of venous but not microvessel circulation in the brain. The elevation of the BBB permeability is associated with the decrease of venous CBF and the increase of its complexity. These data suggest that the cerebral veins rather than microvessels are sensitive components of the CBF related to the opening BBB.