Malignant gliomas are highly invasive tumors that use the cerebral vessels for invasion due to high vascular fragility of the blood–brain barrier (BBB). On one hand, glioma is characterized by the BBB disruption, on the other hand, drug brain delivery via the BBB is a big challenge in glioma therapy. The limited information about vascular changes associated with glioma growth is a reason of slow progress in prevention of glioma development. Here, we present in vivo and ex vivo study of the BBB disruption and glioma cells (GCs) migration in rats using fluorescence and confocal microscopy. We uncovered a local breach in the BBB in the main tumor mass but not within the border of normal and malignant cells, where the BBB was impermeable for high weight molecules. The migration of GCs were observed via the cerebral vessels with the intact BBB that was associated with macrophages infiltration. The mechanisms underlying glioma progression remain unknown but there is an evidence that the sympathetic nervous system (SNS) via activation of vascular beta2-adrenoreceptors (B2-ADRs) can play an important role in tumor metastasis. Our results clearly show an increase in the expression of vascular B2-ADRs and production of the beta-arrestin-1 - co-factor of B2-ADRs signaling pathway in rats with glioma. Pharmacological blockade of B2-ADRs reduces the BBB disruption, macrophages infiltration, GCs migration and increases survival rate. These data suggest that the blockade of B2-ADRs may be a novel adjuvant therapeutic strategy to reduce glioma progression and prevent metastasis.

Here, we discuss an important problem in medicine as development of effective strategies for brain drug delivery. This problem is related to the blood-brain barrier (BBB), which is a “customs” controlling the entrance of different molecules from blood into the brain protecting the normal function of central nervous system (CNS). We show three interfaces of anatomical side of BBB and two functional types of BBB — physical and transporter barriers. Although this protective mechanism is essential for health of CNS, it also creates a hindrance to the entry of drugs into the brain. The BBB was discovered over 100 years ago but till now, there is no effective methods for brain drug delivery. There are more than 70 approaches for overcoming BBB including physical, chemical and biological techniques but all of these tools have limitation to be widely used in clinical practice due to invasiveness, challenge in performing, very costly or limitation of drug concentration. Photodynamic therapy (PDT) is usual clinical method of surgical navigation for the resection of brain tumor and anti-cancer therapy. Nowadays, the application of PDT is considered as a potential promising tool for brain drug delivery via opening of BBB. Here, we show the first successful experimental results in this field discussing the adventures and disadvantages of PDT-related BBB disruption as well as alternatives to overcome these limitations and possible mechanisms with new pathways for brain clearance via glymphatic and lymphatic systems.