Real-time monitoring of human blood-brain barrier disruption.

Chemotherapy aided by opening of the blood-brain barrier with intra-arterial infusion of hyperosmolar mannitol improves the outcome in primary central nervous system lymphoma. Proper opening of the blood-brain barrier is crucial for the treatment, yet there are no means available for its real-time monitoring. The intact blood-brain barrier maintains a mV-level electrical potential difference between blood and brain tissue, giving rise to a measurable electrical signal at the scalp. Therefore, we used direct-current electroencephalography (DC-EEG) to characterize the spatiotemporal behavior of scalp-recorded slow electrical signals during blood-brain barrier opening. Nine anesthetized patients receiving chemotherapy were monitored continuously during 47 blood-brain barrier openings induced by carotid or vertebral artery mannitol infusion. Left or right carotid artery mannitol infusion generated a strongly lateralized DC-EEG response that began with a 2 min negative shift of up to 2000 µV followed by a positive shift lasting up to 20 min above the infused carotid artery territory, whereas contralateral responses were of opposite polarity. Vertebral artery mannitol infusion gave rise to a minimally lateralized and more uniformly distributed slow negative response with a posterior-frontal gradient. Simultaneously performed near-infrared spectroscopy detected a multiphasic response beginning with mannitol-bolus induced dilution of blood and ending in a prolonged increase in the oxy/deoxyhemoglobin ratio. The pronounced DC-EEG shifts are readily accounted for by opening and sealing of the blood-brain barrier. These data show that DC-EEG is a promising real-time monitoring tool for blood-brain barrier disruption augmented drug delivery.

Promising treatment results with blood brain barrier disruption (BBBD) based immunochemotherapy combined with autologous stem cell transplantation (ASCT) in patients with primary central nervous system lymphoma (PCNSL).

Primary central nervous system lymphoma (PCNSL) is a rare brain tumour with a dismal prognosis. Several phase II studies with high-dose methotrexate-based regimens have shown promising early results, but in all hospital-based data published so far, the disease outcome has been poor. Patients with relapsed or refractory disease have a dismal prognosis. We performed retrospective analysis to evaluate results and tolerabilities of BBBD therapy in combination with high-dose therapy supported by autologous stem cell transplantation. We analysed 25 patients (age range: 40-71 years) who were treated in first or second line with BBBD therapy. When we started BBBD treatment, patients had relapsed or refractory PCNSL or they did not tolerate Bonn-like therapy. In recent years, some of the patients were treated in first line. We found promising response rates. Altogether 19 (76 %) of the patients achieved a complete response (CR). Two-year progression-free survival (PFS) and overall survival (OS) rates were 61 and 57 % respectively and the five-year OS was 47 %. Patients who were treated with a five-drug therapy had a very promising prognosis. The CR rate was 100 % in first-line therapy and 60 % in relapsed cases. These findings suggest that BBBD is a promising therapy for PCNSL, especially for patients in first line, but also for patients with relapsed or refractory disease after conventional chemotherapy, who commonly have a very poor prognosis. Treatment-related toxicity was generally manageable. Thus, BBBD followed by ASCT could be a treatment of choice in transplant-eligible patients with PCNSL.

[Chemotherapy in conjunction with blood brain barrier disruption in the treatment of primary central nervous system lymphoma]. / Veri-aivoesteen avaaminen tehokeinona aivolymfooman solunsalpaajahoidossa.

Primary central nervous system lymphoma (PCNSL) is sensitive to both chemotherapy and radiation, but the blood-brain barrier limits the usefulness of the most effective chemotherapeutic agents. On the other hand radiation therapy carries along serious long term adverse events. In BBBD-therapy the blood-brain barrier is opened with intra-arterial mannitol infusion thus permitting both the chemotherapeutics and antibodies to enter through blood-brain barrier. So far 17 patients have started the therapy in our clinics. Ten patients have reached a complete response and 8 of these responses are ongoing with follow-up times of 6-62 months.