A B S T R A C T The present study describes a canine model of transient reversible blood-brain barrier disruption with hyperosmolar mannitol infusion into the internal carotid artery. Studies in this model show that osmotic blood-brain barrier disruption before intracarotid infusion of methotrexate results in markedly elevated (therapeutic) levels of drug in the ipsilateral cerebral hemisphere. Levels in the cerebrospinal fluid correlate poorly and inconsistently with brain levels. Computerized tomograms in this canine model provide a noninvasive monitor of the degree, timecourse, and localization of osmotic blood-brain barrier disruption.
Current experience with 12 patients studied prospectively suggests a new approach in the diagnosis and treatment of primary central nervous system (CNS) lymphoma, integrating the techniques of needle brain biopsy, immunohistochemical staining for monoclonal antibody and chemotherapeutic drug delivery in association with blood-brain barrier modification. Computed tomography (CT)-guided needle biopsy of deep parenchymal lesions contributed to the diagnosis in six patients. Immunohistochemical staining methods detected monoclonal immunoglobulins in those patients so tested. Following diagnosis, the patients have been treated with multi-agent chemotherapy in conjunction with osmotic blood-brain barrier modification (five without antecedent cranial irradiation) with an initial complete response rate by CT scan in nine patients, a median follow-up of 19 months from diagnosis, and a 1-year survival of 75%. This experience emphasizes the value of CT-guided stereotaxic or CT-guided needle biopsy, which limits the need for therapy without a diagnosis or the need for a major craniotomy in what are commonly deep, paraventricular lesions. Immunoperoxidase cytochemical stains can detect monoclonal immunoglobulin characteristic of CNS B-cell malignant lymphomas and provide an important diagnostic aid when only modest quantities of tissue or cells are obtained. Finally, chemotherapy administered in conjunction with osmotic blood-brain barrier modification results in a clinical response rate and survival that are at least as effective as radiotherapy as a primary therapeutic modality.
Reversible osmotic blood-brain barrier (BBB) modification was used in 38 patients with glioblastoma to enhance the delivery of chemotherapeutic agents. The patients ranged in age from 14 to 70 years (mean, 43), and all had prior surgery and radiation; 5 had also received systemic chemotherapy. Karnofsky Performance Status (KPS) scores ranged from 60 to 100% (mean, 79) on admission to the treatment program. Barrier modification was achieved by intracarotid or intravertebral artery infusion of mannitol, and a chemotherapy regimen of methotrexate, cytoxan, and procarbazine was given in conjunction with barrier modification. The 38 glioblastoma patients were compared to two control groups of patients with glioblastoma; these encompassed 14 patients treated with surgery and radiation and 8 treated with surgery, radiation, and systemic chemotherapy. Survival analysis using the Cox Proportional Hazards Regression Model (corrected for age, sex, presence or absence of necrosis, and functional status) showed that patients receiving chemotherapy with BBB modification had a statistically significant (P = 0.0006) longer expected survival (17.5 months) than the control groups (12.8 and 11.4 months, respectively). Presently 16 patients of the barrier-enhanced treatment group are alive at 5 to 42 months from diagnosis (median, 20) with KPS scores ranging from 40 to 90% (median, 65). The neurological complications seen included a stroke-like syndrome in 3 patients (1 with decreased motor movement in the hand, 1 with marked hemiparesis, and 1 with hemiplegia), transient exacerbation of preexisting neurological deficits lasting 2 to 3 days, and a 15% incidence of seizures during or within 24 hours of the BBB modification. In 2 of the 38 patients, radiographic documentation of central nervous system tumor regression concurrent with the development of new tumor nodule(s) in portions of the brain distant from the region of osmotic BBB opening was seen. These studies indicate that chemotherapeutic drug delivery to tumors (as well as surrounding brain) can be augmented by osmotic BBB modification and that such therapy can result in a prolongation of survival.
Reversible transient osmotic blood-brain barrier disruption was used to increase drug delivery to the brain. Methotrexate was administered 33 times to six patients with brain tumors after barrier disruption. No permanent complications were seen. Serial enhanced computed tomographic (CT) scans and quantification by CT tomographic number indicated that disruption increased drug delivery to the tumor and immediate surrounding brain. Neuroradiologic evaluation showed that drug in the tumor persisted longer after barrier disruption than when delivered without disruption. The concentration of methotrexate in spinal fluid did not correlate with the degree of barrier disruption measured by CT and radionuclide scans. In one patient an anatomic variation in the circle of Willis resulted in barrier disruption extending into the posterior fossa without ill effect. Osmotic blood-brain barrier disruption appears to be a safe procedure in man, able to increase drug delivery to both malignant brain tumors and surrounding brain parenchyma.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.