Implications of the blood–brain barrier in primary central nervous system lymphoma

Recent Advances in Nanobiotechnology for the Treatment of Non-Hodgkin's Lymphoma

Lymphoma is the eighth most common type of cancer worldwide. Currently, lymphoma is mainly classified into two main groups: Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL), with NHL accounting for 80% to 90% of the cases. NHL is primarily divided into B, T, and natural killer (NK) cell lymphoma. Nanotechnology is developing rapidly and has made significant contributions to the field of medicine. This review summarizes the advancements of nanobiotechnology in recent years and its applications in the treatment of NHL, especially in diffuse large B cell lymphoma (DLBCL), primary central nervous system lymphoma (PCNSL), and follicular lymphoma (FL). The technologies discussed include clinical imaging, targeted drug delivery, photodynamic therapy (PDT), and thermodynamic therapy (TDT) for lymphoma. This review aims to provide a better understanding of the use of nanotechnology in the treatment of non-Hodgkin's lymphoma.

Hepatotoxicity from high-dose methotrexate in primary central nervous system lymphoma

Background

High-dose methotrexate (HDMTX) is a mainstay of primary central nervous system lymphoma (PCNSL) treatment. Transient hepatotoxicity from HDMTX has been characterized in pediatric patients but not in adults. We sought to characterize hepatotoxicity in adult PCNSL patients undergoing HDMTX treatment.

Methods

Retrospective study of 65 PCNSL patients treated at the University of Virginia from 02/01/2002 to 04/01/2020 was performed. Hepatotoxicity was defined using National Cancer Institute Common Toxicity Criteria (CTC) for adverse events, fifth version. High-grade hepatotoxicity was defined as a bilirubin or aminotransferase CTC grade of 3 or 4. Relationships between clinical factors and hepatotoxicity were assessed with logistic regression.

Results

Most patients (90.8%) had a rise of at least one aminotransferase CTC grade during HDMTX treatment. 46.2% had high-grade hepatotoxicity based on aminotransferase CTC grade. No patients developed high-grade bilirubin CTC grades during chemotherapy. Liver enzyme test values decreased to low CTC grade or normal in 93.8% of patients after the conclusion of HDMTX treatment without treatment regimen changes. Prior ALT elevation (P = .0120) was a statistically significant predictor of high-grade hepatotoxicity during treatment. Prior history of hypertension was associated with increased risk of toxic serum methotrexate levels during any cycle (P = .0036).

Conclusions

Hepatotoxicity develops in the majority of HDMTX-treated PCNSL patients. Transaminase values decreased to low or normal CTC grades in almost all patients after treatment, without modification of MTX dosage. Prior ALT elevation may predict patients' increased hepatotoxicity risk, and hypertension history may be a risk factor for delayed MTX excretion.

Extranodal classical Hodgkin lymphoma involving the spinal cord: case report and review of the literature

Primary CNS involvement is very rare in Hodgkin lymphoma. Here we present two cases of spinal cord dissemination. Two women of 40 and 65 years of age presented symptoms of spinal cord injury; imaging showed an intramedullary mass in T10 and T2, respectively, without vertebral involvement and upper diaphragmatic lymph nodes. Lymph-node biopsy confirmed the diagnosis of classical Hodgkin lymphoma in both patients. The first patient received four cycles of chemotherapy (escalated BEACOPP and ABVD) with intrathecal therapy, and the second four cycles of doxorubicin, vinblastine, dacarbazine (AVD) and local irradiation after surgery decompression. Complete metabolic response was obtained at the end of treatment. After 5 and 7 years of follow-up respectively, neurological deficits persisted in both.

Lymph-node infiltration is the most common presentation in Hodgkin lymphoma at diagnosis. Primary extranodal involvement is rare and spinal cord infiltration exceptional. Back pain, tingling and vesico-sphincter dysfunctions are the main symptoms. 18F-fluorodeoxyglucose (FDG) PET and MRI can detect the location and extension of neurological involvement. We present here two cases of tumoral myelitis and a review of the literature. Local treatment (surgery/radiotherapy) is often administered together with chemotherapy to optimize local control and to avoid long-term sequelae.

MIF in the cerebrospinal fluid is decreased during relapsing-remitting while increased in secondary progressive multiple sclerosis

BACKGROUND

Macrophage migration inhibitory factor (MIF) is involved in the function of both the innate and adaptive immune systems and in neuroprotection and has recently been implicated in multiple sclerosis (MS).

OBJECTIVES

Determination of MIF levels in the cerebrospinal fluid (CSF) of patients with distinct subtypes of MS and the cellular localization of MIF in human brain tissue.

METHODS

The levels of MIF were investigated in CSF from patients with clinically isolated syndrome (CIS) (n = 26), relapsing-remitting MS (RRMS) (n = 22), secondary progressive MS (SPMS) (n = 19), and healthy controls (HCs) (n = 24), using ELISA. The effect of disease-modifying therapies in the RRMS and SPMS cohorts were examined. Cellular distribution of MIF in the human brain was studied using immunochemistry and the newly available OligoInternode database.

RESULTS

MIF was significantly decreased in treatment-naïve CIS and RRMS patients compared to HCs but was elevated in SPMS. Interestingly, MIF levels were sex-dependent and significantly higher in women with CIS and RRMS. MIF expression in the human brain was localized to neurons, astrocytes, pericytes, and oligo5 oligodendrocytes but not in microglia.

CONCLUSION

The finding that MIF was decreased in newly diagnosed CIS and RRMS patients but was high in patients with SPMS may suggest that MIF levels in CSF are regulated by local MIF receptor expression that affects the overall MIF signaling in the brain and may represent a protective mechanism that eventually fails.

An Overview of Nanotechnologies for Drug Delivery to the Brain

Drug delivery to the brain has been one of the toughest challenges researchers have faced to develop effective treatments for brain diseases. Owing to the blood–brain barrier (BBB), only a small portion of administered drug can reach the brain. A consequence of that is the need to administer a higher dose of the drug, which, expectedly, leads to a variety of unwanted side effects. Research in a variety of different fields has been underway for the past couple of decades to address this very serious and frequently lethal problem. One area of research that has produced optimistic results in recent years is nanomedicine. Nanomedicine is the science birthed by fusing the fields of nanotechnology, chemistry and medicine into one. Many different types of nanomedicine-based drug-delivery systems are currently being studied for the sole purpose of improved drug delivery to the brain. This review puts together and briefly summarizes some of the major breakthroughs in this crusade. Inorganic nanoparticle-based drug-delivery systems, such as gold nanoparticles and magnetic nanoparticles, are discussed, as well as some organic nanoparticulate systems. Amongst the organic drug-delivery nanosystems, polymeric micelles and dendrimers are discussed briefly and solid polymeric nanoparticles are explored in detail.

Urine volume to hydration volume ratio is associated with pharmacokinetics of high-dose methotrexate in patients with primary central nervous system lymphoma

High-dose methotrexate (HD-MTX)-based chemotherapy is the first-line treatment for primary central nervous system lymphoma (PCNSL), but is associated with severe adverse effects, including myelosuppression and renal impairment. MTX is primarily excreted by the kidneys. Renal function calculated using serum creatinine (Scr) derived from muscle may be overestimated in elderly PCNSL patients. Therefore, we aimed to construct a population pharmacokinetic model in PCNSL patients and explore the factors associated with MTX clearance. Sixteen PCNSL patients (median age, 66 years) treated with HD-MTX were included, and serum MTX concentrations were measured at 193 points in 49 courses. A population pharmacokinetic analysis was performed using NONMEM. A Monte Carlo simulation was conducted, in which serum MTX concentrations were stratified into three groups of creatine clearance (Ccr) (50, 75, and 100 ml/min) with three groups of the urine volume to hydration volume (UV/HV) ratio (<1, 1-2, and >2). The final model was constructed as follows: MTX clearance = 4.90·(Ccr/94.5)0.456 ·(UV/HV)0.458 . In the Monte Carlo simulation, serum MTX concentrations were below the standard values (10, 1, and 0.1 µM at 24, 48, and 72 h, respectively, after the start of the MTX administration) in most patients with UV/HV >2, even with Ccr of 50 ml/min. Conversely, half of the patients with UV/HV <1 and Ccr of 50 ml/min failed to achieve the standard values. The present results demonstrated that the UV/HV ratio was useful for describing the pharmacokinetics of MTX in PCNSL patients.

Bile acids as novel enhancers of CNS targeting antitumor drugs: a comprehensive review

Despite a relatively low prevalence of primary brain tumors, they continuously attract scientific interest because of the complexity of their treatment due to their location behind the blood-brain barrier. The main challenge in treatment of brain tumors is not the efficacy of the drugs, per se, but the low efficiency of drug delivery to malignant cells. At the core of the problem is the complex structure of the blood-brain barrier. Nowadays, there is evidence supporting the claim that bile acids have the ability to cross the blood-brain barrier. That ability can be exploited by taking a part in novel drug carrier designs. Bile acids represent a drug carrier system as a part of a mixed micelle composition, bilosomes and conjugates with various drugs. This review discusses the current knowledge related to bile acid molecules as drug penetration modifying agents, with the focus on central nervous system antitumor drug delivery.

Performance of diffusion and perfusion MRI in evaluating primary central nervous system lymphomas of different locations

Background

Diffusion and perfusion MRI can invasively define physical properties and angiogenic features of tumors, and guide the individual treatment. The purpose of this study was to investigate whether the diffusion and perfusion MRI parameters of primary central nervous system lymphomas (PCNSLs) are related to the tumor locations.

Methods

We retrospectively reviewed the diffusion, perfusion, and conventional MRI of 68 patients with PCNSLs at different locations (group 1: cortical gray matter, group 2: white matter, group 3: deep gray matter). Relative maximum cerebral blood volume (rCBV_max) from perfusion MRI, minimum apparent diffusion coefficients (ADC_min) from DWI of each group were calculated and compared by one-way ANOVA test. In addition, we compared the mean apparent diffusion coefficients (ADC_mean) in three different regions of control group.

Results

The rCBV_max of PCNSLs yielded the lowest value in the white matter group, and the highest value in the cortical gray matter group (P < 0.001). However, the ADC_min of each subgroup was not statistically different. The ADC_mean of each subgroup in control group was not statistically different.

Conclusion

Our study confirms that rCBV_max of PCNSLs are related to the tumor location, and provide simple but effective information for guiding the clinical practice of PCNSLs.

Effects of Radiation Therapy on Neural Stem Cells

Brain and nervous system cancers in children represent the second most common neoplasia after leukemia. Radiotherapy plays a significant role in cancer treatment; however, the use of such therapy is not without devastating side effects. The impact of radiation-induced damage to the brain is multifactorial, but the damage to neural stem cell populations seems to play a key role. The brain contains pools of regenerative neural stem cells that reside in specialized neurogenic niches and can generate new neurons. In this review, we describe the advances in radiotherapy techniques that protect neural stem cell compartments, and subsequently limit and prevent the occurrence and development of side effects. We also summarize the current knowledge about neural stem cells and the molecular mechanisms underlying changes in neural stem cell niches after brain radiotherapy. Strategies used to minimize radiation-related damages, as well as new challenges in the treatment of brain tumors are also discussed.

Primary Central Nervous System Lymphoma (PCNSL): Analysis of Treatment by Gamma Knife Radiosurgery and Chemotherapy in a Prospective, Observational Study

BACKGROUND

Primary central nervous system lymphoma (PCNSL) is a rare cancer accounting for less than 3% of primary brain and central nervous system (CNS) tumors. Tissues involved include the brain parenchyma, leptomeninges, eyes, and spinal cord. High-dose methotrexate (MTX) is the gold standard for newly diagnosed PCNSL. However, Gamma Knife radiosurgery (GKRS) may be efficacious as a co-adjuvant treatment. The purpose of this prospective observational cohort study is to determine the effectiveness of MTX in combination with GKRS in the treatment of PCNSL.

METHODS

This is a prospective, observational cohort study evaluating the treatment of histologically confirmed PCNSL with MTX as a single agent in a dose of 8 g/m2 (control) and treatment with MTX, plus GKRS. Strict inclusion and exclusion criteria were employed. Primary outcomes were measured by survival rate. Secondary outcomes were assessed by the tumor's responsiveness to treatment and reduction in size as noted on imaging.

RESULTS

Between January 2007 and January 2012, 128 charts were evaluated. Included in this evaluation were 73 chemotherapy (control) and 55 chemotherapy, plus GKRS, patients (variable). The follow-up period was 24 to 49 months (mean: 36.9 months). There were no statistically significant differences in patient demographics or histology diagnosis. Patients were treated with GK doses ranging from 11 Gy to 16 Gy (median: 11 Gy). The median survival rate from initial diagnosis was 26.8 months in the chemotherapy group and 47.6 in the chemotherapy, plus GKRS, group (p-value: 0.0034). All lesions showed a complete response after GKRS when evaluated using magnetic resonance imaging after three to eight weeks (mean range: 6.3 weeks).

CONCLUSIONS

The use of GKRS is non-invasive, safe, and shows rapid success, improving the prognosis of the patient. This noninvasive treatment modality should be considered as an option for patients with PCNSL. In our study, GKRS as a co-adjuvant therapy to high-dose methotrexate was statistically significant for greater tumor control, enhanced overall survival period, and a lesser number of complications.

Tumor Vascular Permeability Pattern Is Associated With Complete Response in Immunocompetent Patients With Newly Diagnosed Primary Central Nervous System Lymphoma: Retrospective Cohort Study

A dynamic contrast-enhanced MR imaging (DCE-MRI) could provide the information about tumor drug delivery efficacy. We investigated the potential utility of the permeability pattern of DCE-MRI for predicting tumor response to high dose-methotrexate treatment and progression-free survival (PFS) in patients with primary CNS lymphoma (PCNSL). Clinical and conventional imaging parameters were assessed as potential predictors of tumor response in 48 immunocompetent PCNSL patients in a preliminary study. Fifty additional immunocompetent patients (27 men and 23 women; mean age, 60.6 years) with PCNSL underwent DCE-MRI before starting first-line treatment with high dose-methotrexate. The DCE-MRI pattern was categorized as diffuse or nondiffuse. After 4 courses of high dose methotrexate, patients underwent follow-up brain MR imaging to identify their complete response (CR). Predictors of CR and PFS were analyzed using clinical parameters, conventional MRI, and DCE-MRI. CR was noted in 20 (74.1%) of 27 patients with diffuse DCE-MRI pattern and in 4 (17.4%) of 23 patients with nondiffuse DCE-MRI pattern. The diffuse DCE-MRI pattern showed a significantly higher association with CR than the nondiffuse pattern (P < 0.001). Multivariate Cox proportional hazards model revealed that the DCE-MRI pattern (hazard ratio = 0.70; P = 0.045), age (hazard ratio = 1.47; P = 0.041), and adjuvant autologous stem-cell transplantation (hazard ratio = 6.97; P = 0.003) tended to be associated with a PFS. The pretreatment diffuse DCE-MRI pattern can be used as a potential imaging biomarker for predicting CR and a longer PFS in patients with newly diagnosed PCNSLs.

Successful treatment of Epstein-Barr virus-related post-transplant lymphoproliferative disease with central nervous system involvement following allogeneic haematopoietic stem cell transplantation - a case study

Post-transplant lymphoproliferative disease (PTLD) is a rare but severe form of Epstein-Barr virus (EBV)-driven complication that develops in patients after haematopoietic stem cell transplantation. In rare cases it manifests as primary central nervous system (CNS) involvement, which is thought to be the most unfavourable localisation with respect to outcome. Disease confined to the CNS is much more challenging than systemic PTLD, and one of the contributing factors is the limited drug penetration across the blood-brain barrier. We describe the case of a 29-year-old woman who was successfully treated for PTLD with CNS involvement. The patient was diagnosed with T-cell lymphoblastic lymphoma and underwent the procedure of haematopoietic stem cell transplantation from an unrelated donor. Two months after transplantation she manifested severe headache and progressive mental deterioration accompanied by enlargement of the lymph nodes. Magnetic resonance imaging (MRI) scan revealed segmental, asymmetrical thickening of the meninges. Based on the clinical picture and the laboratory findings diagnosis of PTLD was made. The patient was effectively treated with reduction of immunosuppressive therapy and intravenous rituximab. Initially started intrathecal chemotherapy was stopped due to iatrogenic complications. We conclude that in this case the involvement of meninges in the course of the lymphoproliferative process might have compromised the blood-brain barrier. This factor probably improved rituximab's penetration to CNS, contributing to our patient's recovery.

Enhancing the efficacy of drug-loaded nanocarriers against brain tumors by targeted radiation therapy

Glioblastoma multiforme (GBM) is a common, usually lethal disease with a median survival of only ~15 months. It has proven resistant in clinical trials to chemotherapeutic agents such as paclitaxel that are highly effective in vitro, presumably because of impaired drug delivery across the tumor's blood-brain barrier (BBB). In an effort to increase paclitaxel delivery across the tumor BBB, we linked the drug to a novel filomicelle nanocarrier made with biodegradable poly(ethylene-glycol)-block-poly(ε-caprolactone-r-D,L-lactide) and used precisely collimated radiation therapy (RT) to disrupt the tumor BBB's permeability in an orthotopic mouse model of GBM. Using a non-invasive bioluminescent imaging technique to assess tumor burden and response to therapy in our model, we demonstrated that the drug-loaded nanocarrier (DLN) alone was ineffective against stereotactically implanted intracranial tumors yet was highly effective against GBM cells in culture and in tumors implanted into the flanks of mice. When targeted cranial RT was used to modulate the tumor BBB, the paclitaxel-loaded nanocarriers became effective against the intracranial tumors. Focused cranial RT improved DLN delivery into the intracranial tumors, significantly improving therapeutic outcomes. Tumor growth was delayed or halted, and survival was extended by &gt;50% (p<0.05) compared to the results obtained with either RT or the DLN alone. Combinations of RT and chemotherapeutic agents linked to nanocarriers would appear to be an area for future investigations that could enhance outcomes in the treatment of human GBM.

Intrathecal therapy with rituximab in central nervous system involvement of post-transplant lymphoproliferative disorder

Post-transplant lymphoproliferative disorder (PTLD) caused by Epstein-Barr virus (EBV) is a severe complication in high-risk allogeneic hematopoietic stem cell transplant (HSCT) recipients. Central nervous system (CNS) involvement of PTLD is a very rare event in patients with HSCT. As no established standard therapy in CNS-EBV-PTLD is available, the aim of this study was analysis of the safety and efficacy of intrathecal rituximab therapy in a group of eight children and adolescents with CNS-EBV-PTLD. Seven patients responded to therapy: all clinical symptoms and EBV-DNA viral load resolved after a median 2 (range: 1-7) doses of rituximab. However, some magnetic resonance imaging (MRI) changes in brain scan persisted in two patients. In all patients, except one, no adverse events of the therapy were observed. In conclusion, intrathecal rituximab administration seems to be an effective and safe method of treatment of CNS-EBV-PTLD in pediatric stem cell recipients. We recommend this treatment modality for further investigation.

Ocular relapse of primary brain lymphoma in immunocompetent patient, treated with intrathecal rituximab

Primary brain lymphoma is a rare variant of extranodal non-Hodgkin's B-cell lymphoma. In >90% of cases, this is diffuse large B-cell lymphoma with CD20 expression and is confined to the brain, meninges, spinal cord, and eyes. It accounts for fewer than 7% of primary brain tumors. Its incidence has been rising in recent years in immunocompetent patients in their fifth and sixth decades. The rate of relapse after initial therapy based on high-dose methotrexate and/or total brain irradiation is high. There is no consensus for treating relapse, which ranges from retreatment with high doses of methotrexate, polychemotherapy, high doses of chemotherapy backed up by autologous stem-cell transplant to intrathecal chemotherapy, with widely differing results. Given the lack of consensus and poor results, new therapy options have appeared, including immunotherapy with rituximab. At a systemic level, alongside chemotherapy, its results are very modest and limited due to the low concentration it reaches in cerebrospinal fluid (CSF). However, its intrathecal and intraventricular use, though only isolated cases have been reported, has provided promising results.

Morphology and properties of brain endothelial cells

The molecular advances in various aspects of brain endothelial cell function in steady states are considerable and difficult to summarize in one chapter. Therefore, this chapter focuses on endothelial permeability mechanisms in steady states and disease namely vasogenic edema. The morphology and properties of caveolae and tight junctions that are involved in endothelial permeability to macromolecules are reviewed. Endothelial transport functions are briefly reviewed. Diseases with alterations of endothelial permeability are mentioned and details are provided of the molecular alterations in caveolae and tight junctions in vasogenic edema. Other factors involved in increased endothelial permeability such as the matrix metalloproteinases are briefly discussed. Of the modulators of endothelial permeability, angioneurins such as the vascular endothelial growth factors and angiopoietins are discussed. The chapter concludes with a brief discussion on delivery of therapeutic substances across endothelium.

Chemotherapy in newly diagnosed primary central nervous system lymphoma

Primary central nervous system lymphoma (PCNSL) accounts for only 3% of brain tumors. It can involve the brain parenchyma, leptomeninges, eyes and the spinal cord. Unlike systemic lymphoma, durable remissions remain uncommon. Although phase III trials in this rare disease are difficult to perform, many phase II trials have attempted to define standards of care. Treatment modalities for patients with newly diagnosed PCNSL include radiation and/or chemotherapy. While the role of radiation therapy for initial management of PCNSL is controversial, clinical trials will attempt to improve the therapeutic index of this modality. Routes of chemotherapy administration include intravenous, intraocular, intraventricular or intra-arterial. Multiple trials have outlined different methotrexate-based chemotherapy regimens and have used local techniques to improve drug delivery. A major challenge in the management of patients with PCNSL remains the delivery of aggressive treatment with preservation of neurocognitive function. Because PCNSL is rare, it is important to perform multicenter clinical trials and to incorporate detailed measurements of long-term toxicities. In this review we focus on different chemotherapeutic approaches for immunocompetent patients with newly diagnosed PCNSL and discuss the role of local drug delivery in addition to systemic therapy. We also address the neurocognitive toxicity of treatment.

Intra-arterial chemotherapy with osmotic blood-brain barrier disruption for aggressive oligodendroglial tumors: results of a phase I study

OBJECTIVE

Refractory anaplastic oligodendroglioma and oligoastrocytoma tumors are challenging to treat. This trial primarily evaluated toxicity and estimated the maximum tolerated dose of intra-arterial (IA) melphalan, IA carboplatin, and intravenous (IV) etoposide phosphate in conjunction with blood-brain barrier disruption in these tumors. The secondary measure was efficacy.

METHODS

Thirteen patients with temozolomide-refractory anaplastic oligodendroglioma (11 patients) or oligoastrocytoma (2 patients) underwent blood-brain barrier disruption with carboplatin (IA, 200 mg/m(2)/d), etoposide phosphate (IV, 200 mg/m(2)/d), and melphalan (IA, dose escalation) every 4 weeks, for up to 1 year. Patients underwent melphalan dose escalation (4, 8, 12, 16, and 20 mg/m(2)/d) until the maximum tolerated dose (1 level below that producing grade 4 toxicity) was determined. Toxicity and efficacy were assessed.

RESULTS

Two of 4 patients receiving IA melphalan at 8 mg/m(2)/d developed grade 4 thrombocytopenia; thus, the melphalan maximum tolerated dose was 4 mg/m/d. Adverse events included asymptomatic subintimal tear (1 patient) and grade 4 thrombocytopenia (3 patients). Two patients demonstrated complete response, 3 had partial responses, 5 demonstrated stable disease, and 3 progressed. Median overall progression-free survival was 11 months. Patients with complete or partial response demonstrated deletion of chromosomes 1p and 19q. In the 5 patients with stable disease, 2 demonstrated 1p and 19q deletion, and 3 demonstrated 19q deletion only.

CONCLUSION

In patients with anaplastic oligodendroglioma or oligoastrocytoma tumors in whom temozolomide treatment has failed, osmotic blood-brain barrier disruption with IA carboplatin, IV etoposide phosphate, and IA melphalan (4 mg/m(2)/d for 2 days) shows acceptable toxicity and encouraging efficacy, especially in patients demonstrating 1p and/or 19q deletion.

Blood-brain barrier disruption and intra-arterial methotrexate-based therapy for newly diagnosed primary CNS lymphoma: a multi-institutional experience

PURPOSE Primary CNS lymphoma (PCNSL) is confined to the CNS and/or the eyes at presentation and is usually initially treated with intravenous methotrexate-based chemotherapy and whole-brain radiotherapy (WBRT). However, the intact blood-brain barrier (BBB) can limit diffusion of methotrexate into brain and tumor. With BBB disruption (BBBD), enhanced drug delivery to the tumor can be achieved. PATIENTS AND METHODS This report summarizes the multi-institutional experience of 149 newly diagnosed (with no prior WBRT) patients with PCNSL treated with osmotic BBBD and intra-arterial (IA) methotrexate at four institutions from 1982 to 2005. In this series, 47.6% of patients were age > or = 60 years, and 42.3% had Karnofsky performance score (KPS) less than 70 at diagnosis. Results The overall response rate was 81.9% (57.8% complete; 24.2% partial). Median overall survival (OS) was 3.1 years (25% estimated survival at 8.5 years). Median progression-free survival (PFS) was 1.8 years, with 5-year PFS of 31% and 7-year PFS of 25%. In low-risk patients (age < 60 years and KPS > or = 70), median OS was approximately 14 years, with a plateau after approximately 8 years. Procedures were generally well tolerated; focal seizures (9.2%) were the most frequent side effect and lacked long-term sequelae. CONCLUSION This large series of patients treated over a 23-year period demonstrates that BBBD/IA methotrexate-based chemotherapy results in successful and durable tumor control and outcomes that are comparable or superior to other PCNSL treatment regimens.

The blood-brain barrier in brain homeostasis and neurological diseases

Brain endothelial cells are unique among endothelial cells in that they express apical junctional complexes, including tight junctions, which quite resemble epithelial tight junctions both structurally and functionally. They form the blood-brain-barrier (BBB) which strictly controls the exchanges between the blood and the brain compartments by limiting passive diffusion of blood-borne solutes while actively transporting nutrients to the brain. Accumulating experimental and clinical evidence indicate that BBB dysfunctions are associated with a number of serious CNS diseases with important social impacts, such as multiple sclerosis, stroke, brain tumors, epilepsy or Alzheimer's disease. This review will focus on the implication of brain endothelial tight junctions in BBB architecture and physiology, will discuss the consequences of BBB dysfunction in these CNS diseases and will present some therapeutic strategies for drug delivery to the brain across the BBB.

Strategies to advance translational research into brain barriers

There is a paucity of therapies for most neurological disorders--from rare lysosomal storage diseases to major public health concerns such as stroke and Alzheimer's disease. Advances in the targeting of drugs to the CNS are essential for the future success of neurotherapeutics; however, the delivery of many potentially therapeutic and diagnostic compounds to specific areas of the brain is restricted by the blood-brain barrier, the blood-CSF barrier, or other specialised CNS barriers. These brain barriers are now recognised as a major obstacle to the treatment of most brain disorders. The challenge to deliver therapies to the CNS is formidable, and the solution will require concerted international efforts among academia, government, and industry. At a recent meeting of expert panels, essential and high-priority recommendations to propel brain barrier research forward in six topical areas were developed and these recommendations are presented here.

Brain parenchyma involvement as isolated central nervous system relapse of systemic non-Hodgkin lymphoma: an International Primary CNS Lymphoma Collaborative Group report

Isolated central nervous system (CNS) relapse involving the brain parenchyma is a rare complication of systemic non-Hodgkin lymphoma. We retrospectively analyzed patient characteristics, management, and outcomes of this complication. After complete response to initial non-Hodgkin lymphoma treatment, patients with isolated CNS relapse with the brain parenchyma as initial relapse site were eligible. Patients with isolated CNS relapse involving only the cerebrospinal fluid were not eligible. Information on 113 patients was assembled from 13 investigators; 94 (83%) had diffuse large B-cell lymphoma. Median time to brain relapse was 1.8 years (range, 0.25-15.9 years). Brain relapse was identified by neuroimaging in all patients; in 54 (48%), diagnostic brain tumor specimen was obtained. Median overall survival from date of brain relapse was 1.6 years (95% confidence interval, 0.9-2.6 years); 26 (23%) have survived 3 years or more. Median time to progression was 1.0 year (95% confidence interval, 0.7-1.7 years). Age less than 60 years (P = .006) at relapse and methotrexate use (P = .008) as front-line treatment for brain relapse were significantly associated with longer survival in a multivariate model. Our results suggest systemic methotrexate is the optimal treatment for isolated CNS relapse involving the brain parenchyma. Long-term survival is possible in some patients.

Image-guided convection-enhanced delivery platform in the treatment of neurological diseases

Convection-enhanced delivery (CED) of substances within the human brain is becoming a more frequent experimental treatment option in the management of brain tumors, and more recently in phase 1 trials for gene therapy in Parkinson's disease (PD). Benefits of this intracranial drug-transfer technology include a more efficient delivery of large volumes of therapeutic agent to the target region when compared with more standard delivery approaches (i.e., biopolymers, local infusion). In this article, we describe specific technical modifications we have made to the CED process to make it more effective. For example, we developed a reflux-resistant infusion cannula that allows increased infusion rates to be used. We also describe our efforts to visualize the CED process in vivo, using liposomal nanotechnology and real-time intraoperative MRI. In addition to carrying the MRI contrast agent, nanoliposomes also provide a standardized delivery vehicle for the convection of drugs to a specific brain-tissue volume. This technology provides an added level of assurance via visual confirmation of CED, allowing intraoperative alterations to the infusion if there is reflux or aberrant delivery. We propose that these specific modifications to the CED technology will improve efficacy by documenting and standardizing the treatment-volume delivery. Furthermore, we believe that this image-guided CED platform can be used in other translational neuroscience efforts, with eventual clinical application beyond neuro-oncology and PD.