MTX-induced white matter changes are associated with polymorphisms of methionine metabolism

Mini-Review: Aplastic Myelin Following Chemotherapy

The contribution of chemotherapy to improved outcomes for cancer patients is unquestionable. Yet as its applications broaden, so do the concerns for the long-term implications of chemotherapy on the health of cancer survivors, with chemotherapy-related cognitive impairment as a cause for particular urgency. In this mini review, we explore myelin aplasticity following chemotherapy, discussing the role of myelin plasticity in healthy cognition and failure of myelin plasticity chiefly due microenvironmental aberrations in chemotherapy-related cognitive impairment. Possible therapeutic strategies to mitigate chemotherapy-induced myelin dysfunction are also discussed.

Intrathecal Methotrexate-Induced Necrotizing Myelopathy: A Case Report and Review of Histologic Features

Central nervous system (CNS) relapse of acute lymphoblastic leukemia (ALL) is associated with a poor prognosis. However, prophylactic measures, including intrathecal (IT) methotrexate, reduce the incidence of CNS relapse in these patients considerably. Unfortunately, IT methotrexate can cause several neurologic complications, including transverse myelopathy; ie, the development of isolated spinal cord dysfunction over hours or days following the IT infusion of methotrexate, but in the absence of a compressive lesion. Transverse myelopathy following IT methotrexate is a well-established clinical phenomenon, but the histologic features have been described only very rarely. We report the autopsy findings from a 31-year-old man with a history of T-cell ALL who received prophylactic IT methotrexate in anticipation of a bone marrow transplant. Microscopic examination showed transverse necrosis of the thoracic cord, with massive infiltration by macrophages and lymphocytes, and perivascular lymphocytic infiltrates. There was cavitary necrosis of cervical and lumbar spinal cord involving the entire gray matter and focal white matter, as well as extensive subpial vacuolar degeneration of the dorsal and lateral columns.

Subacute Methotrexate Encephalopathy Mimicking Ischemic Stroke With Dynamic Changes on Magnetic Resonance Imaging

We report a 35-year-old woman who suddenly developed left hemiparesis and dysarthria at 13days after treatment with intrathecal and intravenous methotrexate for intravascular large B cell lymphoma with possible central nervous system infiltration. Seven hours after onset, she developed further right hemiparesis and aphasia. However, the majority of neurologic symptoms disappeared spontaneously and completely by 34hours. We also recorded the dynamic progression and regression of abnormal signals in the bilateral corona radiata on diffusion-weighted imaging, in parallel with neurologic symptoms. The rapid reversal of MR abnormalities and neurologic symptoms allowed us to diagnose methotrexate encephalopathy, and exclude intravascular large B cell lymphoma recurrence and regular brain infarction. The case provides new data on the dynamic changes of abnormal signals on magnetic resonance imaging in methotrexate encephalopathy over a short recovery time.

Drug resistant epilepsy with mesial temporal sclerosis as possible late neurological complication in two AML survivors after stem cell transplantation

•Mesial temporal sclerosis (MTS) is a potential late complication of hematological malignancies.•Seizures are usually drug resistant with MTS yet seizure freedom may be achieved by surgery.•Early evaluation for epilepsy surgery is warranted for drug resistant seizures due to AML.

Chemotherapy-induced neurotoxicity in pediatric solid non-CNS tumor patients: An update on current state of research and recommended future directions

Neurocognitive sequelae are known to be induced by cranial radiotherapy and central-nervous-system-directed chemotherapy in childhood Acute Lymphoblastic Leukemia (ALL) and brain tumor patients. However, less evidence exists for solid non-CNS-tumor patients. To get a better understanding of the potential neurotoxic mechanisms of non-CNS-directed chemotherapy during childhood, we performed a comprehensive literature review of this topic. Here, we provide an overview of preclinical and clinical studies investigating neurotoxicity associated with chemotherapy in the treatment of pediatric solid non-CNS tumors. Research to date suggests that chemotherapy has deleterious biological and psychological effects, with animal studies demonstrating histological evidence for neurotoxic effects of specific agents and human studies demonstrating acute neurotoxicity. Although the existing literature suggests potential neurotoxicity throughout neurodevelopment, research into the long-term neurocognitive sequelae in survivors of non-CNS cancers remains limited. Therefore, we stress the critical need for neurodevelopmental focused research in children who are treated for solid non-CNS tumors, since they are at risk for potential neurocognitive impairment.

Leukoencephalopathy due to oral methotrexate

Methotrexate (MTX) is considered the main agent for the treatment of rheumatoid arthritis (RA). Neurotoxicity is often mild, but severe encephalopathy can develop, especially with intrathecal or intravenous administration. In rare cases, this syndrome has been observed in patients on long-term low-dose oral administration. A 68-year-old male was diagnosed with RA and on treatment with oral MTX 25 mg weekly for 4 years. The patient started with progressive dysarthria, ataxia and cognitive dysfunction. Complementary tests were normal. Magnetic resonance imaging (MRI) showed hyperintense lesions in both cerebellar hemispheres on T2-weighted and FLAIR images with a diffusion restriction on diffusion-weighted imaging (DWI) and on the apparent diffusion coefficient map (ADC). On postgadolinium T1-weighted images, there were mild enhancements. Spectroscopy showed a demyelinating pattern. A pharmacogenetics determination was made, showing a heterozygous genotype in the MTHFR and ABCB1 genes. Medication with antirheumatic drug was stopped immediately on admission, and the patient gradually improved. MTX-induced leukoencephalopathy can occur even with low-dose administration. The exact pathogenic mechanism is still unknown, but it is hypothesised that it could be the result of a cumulative toxic effect on the blood-brain barrier. The nature of the relationship between the polymorphism and CNS toxicity is still unclear, and thus, further studies are warranted. Often located in the occipital lobes, the involvement of the cerebellum is quite rare. Early recognition of the condition and withdrawal of the drug lead to a better prognosis.

White matter involvement beyond the optic nerves in CRION as assessed by diffusion tensor imaging

BACKGROUND

Chronic relapsing inflammatory optic neuropathy (CRION) is an inflammatory optic neuropathy, characterized by relapses and remissions in patients with normal brain and spinal magnetic resonance imaging (MRI). Discrepancy from other demyelinating diseases is important, and it is still uncertain whether CRION is restricted to the optic pathways or it affects other brain white matter (WM) structures.

OBJECTIVE

To assess WM structure in patients with CRION by using diffusion tensor imaging (DTI).

METHODS

DTI was performed in six CRION patients and six age- and sex-matched healthy controls on a 3 T scanner. Tract-based spatial statistics (TBSS) was used for voxelwise statistical analysis of DTI data. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD) measures were obtained.

RESULTS

TBSS analysis revealed two different patterns of WM alterations in patients with CRION. The optic chiasm and connected structures had significantly higher FA and lower RD, AD and MD in the patients than in the healthy controls. On the other hand, anterior frontal bundles of inferior fronto-occipital tracts, left uncinate fascicule and internal capsule showed decreased FA and increased RD. No correlation was found between the clinical variables and diffusion measures.

CONCLUSION

WM appearing normal on brain MRI shows widespread abnormalities in a cohort of CRION patients as assessed by DTI.

Neurologic complications of chemotherapy and other newer and experimental approaches

Neurologic complications of conventional cytototxic agents as well as those from monoclonal antibodies and targeted therapies are increasingly observed in patients with cancer. The major categories are represented by alkylating agents (platinum compounds, ifosfamide, procarbazine, thiotepa), mitotic spindle inhibitors (vinca alkaloids, taxanes, etoposide, teniposide), proteasome inhibitors (bortezomib), antibiotics, antimetabolites, thalidomide, lenalidomide, topoisomerase inhibitors, interferon-α, hormones, bevacizumab, trastuzumab, and small tyrosine kinase inhibitors. Peripheral neuropathy is a common adverse effect of a number of chemotherapeutic drugs and often represents a critical factor limiting an adequate dose-intensity of chemotherapy. Regarding the central nervous system (CNS), it is vulnerable to many forms of toxicity from chemotherapeutic agents, including encephalopathy syndromes and confusional states, seizures, headache, cerebrovascular complications, visual loss, cerebellar syndromes, and myelopathy. For a given drug, the occurrence of CNS toxicity depends on several factors, including the total dose, route of administration, presence of structural brain lesions, exposure to prior or concurrent irradiation, and interactions with other drugs. However, many of the neurotoxic reactions are rare and idiosyncratic, and remain unpredictable. Several forms of neuroprotection and rehabilitation are being investigated. Last, the so-called "chemobrain" is an emerging issue, as it is a model of a subtle of and long-lasting damage to neuronal structures from some antineoplastic agents.

Association of transcobalamin c. 776C>G with overall survival in patients with primary central nervous system lymphoma

Background:

Chemotherapy for primary central nervous system lymphoma (PCNSL) is based on methotrexate (MTX), which interferes with both nucleic acid synthesis and methionine metabolism. We have reported previously that genetic variants with influence on methionine metabolism are associated with MTX side effects, that is, the occurrence of white matter lesions as a sign of MTX neurotoxicity. Here, we investigated whether such variants are associated with MTX efficacy in terms of overall survival in MTX-treated PCNSL patients.

Methods:

We analysed seven genetic variants influencing methionine metabolism in 68 PCNSL patients treated with systemic and facultative intraventricular MTX-based polychemotherapy (Bonn protocol).

Results:

Median age at diagnosis was 59 years (range: 28–77), 32 patients were female. Younger age (Wald=8.9; P=0.003) and the wild-type C (CC) allele of the genotype transcobalamin c (Tc2). 776C>G (Wald=6.7; P=0.010) were associated with longer overall survival in a multivariate COX regression analysis.

Conclusion:

This observation suggests that the missense variant Tc2. 776C>G influences both neurotoxicity and efficacy of MTX in the Bonn PCNSL protocol.

Cognitive dysfunction among cancer survivors

Cognitive dysfunction among cancer survivors, commonly referred to as "chemobrain," has gained increased attention in the last decade. Cognitive dysfunction is now well recognized among patients with non-central nervous system cancers. It may be a consequence of the cancer, its treatment, or both. Other common problems among cancer survivors, such as insomnia, pain, depression, and fatigue, may play a role in cognitive performance. Three options to assess cognitive function at present include neuropsychologic testing, functional neuroimaging studies, and subjective evaluations, although no "gold standard" currently exists. Treatment options for survivors with cognitive problems are limited because research in this arena is in its infancy.

Central neurotoxicity in cancer chemotherapy: pharmacogenetic insights

Central neurotoxicity of chemotherapy is likely to be multifactorial. There are two hypotheses regarding endogenous mechanisms that may be involved, namely the target and the blood-brain barrier transporter hypotheses. Here, we will review candidate genetic determinants for the risk of chemotherapy-induced neurotoxicity, such as polymorphisms involved in the target mechanism. These include polymorphisms in folate metabolizing enzymes and apolipoprotein E, as well as those in blood-brain barrier transporter genes. Currently, the exact role of pharmacogenetics in mechanisms that lead to central neurotoxicity of chemotherapy has not been fully unraveled. Larger, prospective, longitudinal and more uniform studies are needed, with prechemotherapy and follow-up measurements of neuropsychological performance, MRI, PET, genetic profiles and biomarkers relevant for the proposed target and transporter mechanisms.

Long-term survival in patients with newly diagnosed primary central nervous system lymphoma treated with dexamethasone, etoposide, ifosfamide and carboplatin chemotherapy and whole-brain radiation therapy

In the present study, we aimed to evaluate the safety and efficacy of DeVIC (dexamethasone, etoposide, ifosfamide and carboplatin) chemotherapy for the treatment of patients with primary central nervous system lymphoma (PCNSL). We retrospectively examined 21 patients with newly diagnosed PCNSL who received DeVIC chemotherapy followed by whole-brain radiation therapy (WBRT). The median progression-free survival (PFS) in all patients was 37.4 months and the median duration of overall survival (OS) was 47.8 months. Notably, the median duration of OS was significantly longer in patients who achieved a complete response (CR) after DeVIC chemotherapy (49.0 months) than in those without CR (12.8 months). Furthermore, we found that the overall response rate to the initial DeVIC chemotherapy was 95.2%. No treatment-related deaths were observed. Our study investigated the efficacy of DeVIC chemotherapy in PCNSL patients, and found it to result in favorable survival outcomes in these patients, thus warranting further investigation of it as a therapeutic measure against PCNSL.

[Pharmacologically-induced neurocatastrophes]

Drug-induced adverse reactions represent a significant health problem in developed countries. These events cause 5% of hospital admissions and are one of the main causes of mortality. Neurological manifestations are among the most frequent. This article reviews catastrophic cerebrovascular situations and confusional syndromes, as well as epilepsy, structural encephalopathy, neuromuscular disorders, catastrophic movement disorders and infections, all of which can be drug-induced.

Methotrexate-induced posterior reversible encephalopathy syndrome

WHAT IS KNOWN AND OBJECTIVE

Posterior reversible encephalopathy syndrome (PRES) is described clinically as an acute neurologic deterioration characterized by headache, change in mental status and seizures. Although the mechanism(s) for this syndrome is not fully understood, PRES results from vasogenic edema in areas of the brain supplied by the posterior circulation. Methotrexate (MTX)-induced neurotoxicity is a well-known complication of therapy in the paediatric population but is uncommon in adults.

DETAILS OF THE CASE

We describe a 55-year-old woman with an acute presentation of PRES caused by intrathecal MTX given as part of a treatment regimen for diffuse large B-cell type lymphoma. Both clinical symptoms and radiographic abnormalities resolved 5 days after cessation of treatment.

WHAT IS NEW AND CONCLUSION

We describe what we believe to be the first report of intrathecal MTX-induced PRES in an adult. Clinicians should include MTX-induced PRES in the differential diagnosis of acute neurologic changes in patients receiving this medication. The incidence of MTX-induced neurotoxicity may be under recognized in adults.

Chemotherapy associated central nervous system damage

Chemotherapy is commonly associated with harmful effects to multiple organ systems, including the central nervous system (CNS). Neurotoxicity may manifest as both acute and delayed complications, which is particularly a concern for long-term survivors. Patients may experience a wide range of neurotoxic syndromes, ranging from neuro-vascular complications and focal neurological deficits to generalized neurological decline with cognitive impairment, cortical atrophy and white matter abnormalities. Along with the use of more aggressive and combined treatment modalities and prolonged survival of cancer patients, neurological complications have been observed with increasing frequency. The mechanisms by which cancer therapy, including chemotherapy and radiation, result in neurological complications, have been poorly understood. Recent studies have now started to unravel the cell-biological basis for commonly seen neurotoxic syndromes and have provided compelling explanations for delayed neurological complications, such as cognitive decline, progressive myelin disruption and brain atrophy.

Association of genetic variants of methionine metabolism with methotrexate-induced CNS white matter changes in patients with primary CNS lymphoma

Methotrexate (MTX) is an important anticancer drug and the most efficient chemotherapy component in primary CNS lymphoma (PCNSL). A typical side effect of intravenous high-dose MTX is the occurrence of confluent CNS white matter changes (WMC). Because MTX directly interferes with methionine metabolism, we analyzed the impact of genetic variants of methionine metabolism on the occurrence of WMC as a model of MTX toxicity. In a retrospective analysis of 68 PCNSL patients treated with MTX-based polychemotherapy with (n = 42) or without (n = 26) intraventricular treatment, 10 genetic variants influencing methionine metabolism were analyzed. Pearson's chi(2) test and multinominal regression analysis were used to define the relevance of these genetic variants for the occurrence of WMC. In this patient sample, the occurrence of WMC was significantly predicted by the TT genotype of methylenetetrahydrofolate reductase c.677C>T (chi(2) = 8.67; p = 0.013; df = 2), the AA genotype of methylenetetrahydrofolate reductase c.1298A>C (chi(2) = 13.5; p = 0.001; df = 2), and the GG genotype of transcobalamin 2 c.776C>G (chi(2) = 19.73; p < 0.001), in addition to male gender (chi(2) = 11.95; p = 0.001). These data strengthen the hypothesis that MTX effects are influenced by methionine metabolism, which may offer new strategies to improve MTX-based therapies.

The methylenetetrahydrofolate reductase (MTHFR) variant c.677C>T (A222V) influences overall survival of patients with glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most frequent primary brain tumor in adults. Prognosis is poor. Using a series of 214 GBM patients, we observed an effect of the variant 5,10-methylenetetrahydrofolate reductase (MTHFR) c.677C>T on overall survival. This effect was strongest in patients younger than 60 years at diagnosis (overall survival, median +/- SE: genotype CC, 13 +/- 1 months; CT, 11 +/- 2 months; TT, 7 +/- 3 months; multivariate Cox regression analysis, Wald = 8.58, p = 0.007). In addition, the MTHFR genotype significantly influenced the overall survival of patients with a postoperative Karnofsky score >70 (CC, 12 +/- 2 months; CT, 11 +/- 1 months; TT, 10 +/- 4 months; Wald = 5.89, p = 0.015). These data suggest the MTHFR c.677C>T variant is a risk factor for survival in GBM patients.

Neuropsychological sequelae of non-central nervous system cancer and cancer therapy

Cancer patients report numerous adverse symptoms associated with their disease and treatment including cognitive dysfunction, fatigue, and affective distress. Cognitive dysfunction is ubiquitous in patients with primary central nervous system (CNS) cancer and recent evidence has documented similar deficits in patients with non-CNS cancer as well. Both the cancer itself and treatments including chemotherapy, biological response modifiers, and hormonal therapies have been demonstrated to adversely impact cognitive and neurobehavioral function. Neuroimaging and neurophysiological investigations have likewise revealed alterations in brain function that are helping to account for the nature of these cognitive disorders. Similarly, preclinical animal research is assisting to identify the pathophysiological mechanisms that underlie treatment-related neurotoxicities. The coalescence of multidisciplinary clinical and research efforts hold promise for the development of interventions that may offer neuroprotection in addition to currently available symptomatic therapies and cognitive rehabilitation techniques.

Massive myelinolytic leukoencephalopathy in a patient medicated with low-dose oral methotrexate for rheumatoid arthritis: an autopsy report

The authors describe a 68-year-old female who developed a rapidly progressing leukoencephalopathy involving the cerebrum and brain stem. The disease appeared during low-dose oral methotrexate (MTX) therapy for rheumatoid arthritis. An extensive clinical investigation discounted other possible causes of white matter lesions. Autopsy identified an uninterrupted severe demyelinating, partially liquefactive necrosis-like lesion in the white matter accompanied by astrogliosis and occasional swollen axons therein. The lesion was generally symmetrical, and distributed throughout the whole cerebral white matter except for the bilateral temporal lobes and the rostral part of the frontal lobes. The internal capsules and cerebral peduncles were spongy, and the central and lateral parts of the pons, especially the transverse cerebellopontine tracts, were affected similarly. It was of note that the lesion was accompanied by neither vascular diseases nor lymphocyte infiltration. Thus, the pathological findings were similar to those of a severe form of central and extrapontine myelinolysis, and clearly different from ordinary MTX leukoencephalopathy reported in patients receiving intrathecal or intravenous MTX therapy, known as "disseminated necrotizing leukoencephalopathy". Another possibility is that synergistic effects of several white-matter-damaging disorders may have contributed to the hitherto unknown lesion. To our knowledge, this is the first autopsy record that describes an oral MTX-associated neurological disorder.

The methionine synthase polymorphism c.2756A>G alters susceptibility to glioblastoma multiforme

Genetic polymorphisms of methionine metabolism, in particular methionine synthase (MTR) c.2756A>G (D919G) and methylenetetrahydrofolate reductase (MTHFR) c.677C>T (A222V), have been associated with various human cancers. We investigated MTR c.2756A>G, MTHFR c.677C>T, and a third polymorphism, transcobalamin 2 c.776C>G (P259R), for a potential association with the formation of glioblastoma multiforme. The MTR c.2756G allele was significantly underrepresented among 328 glioblastoma multiforme patients of Caucasian origin when compared with 400 population controls [patients AA/AG/GG: 0.72/0.26/0.02 and controls AA/AG/GG: 0.57/0.38/0.05, degrees of freedom = 2; chi(2) = 17.86 (Pearson); P < 0.001]. No association between glioblastoma multiforme and the two other polymorphisms was observed.

Primary central nervous system lymphoma: biological aspects and controversies in management

INTRODUCTION

This review was produced from the workshop on primary central nervous system lymphoma (PCNSL) at the European Cancer Conference (ECCO 13) in Paris in 2005. It covers the presentation and biological features of the disease (Professor Khe Hoang-Xuan). The role of chemotherapy, including the management of intraocular lymphoma and the use of high dose chemotherapy followed by autologous stem cell transplantation for PCNSL, is discussed (Dr. Andres Ferreri) as well as controversies in the use of whole brain radiotherapy (WBRT) after chemotherapy (Dr. Michele Reni). The topics covered with discussants at the workshop are also summarised.

CONCLUSION

The imaging of the brain and the histopathology including detailed immunohistochemistry is of vital importance in making an accurate diagnosis of the disease and understanding the extent of spread of the disease in the CNS. The importance of high dose methotrexate (HDMTX; dose > or = 1g/m(2)), as the most active drug in the treatment of PCNSL, is stressed. The authors recommend that HDMTX alone or in combination with other active chemotherapy agents should be used to treat PCNSL followed by whole brain radiotherapy (WBRT) unless contraindicated because of the advanced age of the patient and existing cognitive impairment. Only published protocols should be used unless the patient is to be offered a trial that has either national or international support. Baseline neuropsychological tests should be carried out before treatment and repeated during and after treatment. The risks of cognitive impairment associated with the disease, with methotrexate - containing chemotherapy and with whole brain radiotherapy should be explained to patients and relatives when obtaining informed consent. Long-term survival, with current treatment regimes, is possible with PCNSL but this appears limited to patients less than 60 years of age at presentation (mostly patients less than 50 years of age).

Neurologic toxicities of cancer therapies

Neurologic dysfunction is a well-recognized adverse effect of cancer therapeutics. The most common manifestations include peripheral neuropathy and encephalopathy. Often, symptoms resolve or improve upon removal of the offending agent; therefore, it is essential that clinicians recognize the symptoms and signs of injury. Occasionally, symptoms persist or develop after discontinuation of medication and may culminate in disability and diminished quality of life. As our understanding of neurotoxicity improves, medications with less potential for injury may be developed. In addition, potential antidotes to prevent or reverse injury may emerge. This review focuses on the clinical features, mechanisms, and possible therapeutics of the neurotoxicity of chemotherapy. In particular, oxaliplatin, thalidomide, methotrexate, ifosfamide, cytarabine, amifostine, acetyl-L-carnitine, methylene blue, cytokines, and neurotrophins are discussed.

Primary central nervous system lymphoma treated with high-dose methotrexate, high-dose busulfan/thiotepa, autologous stem-cell transplantation and response-adapted whole-brain radiotherapy: results of the multicenter Ostdeutsche Studiengruppe Hamato-Onkologie OSHO-53 phase II study

BACKGROUND

We investigated the efficacy and safety of tandem high-dose methotrexate (HD-MTX) induction followed by high-dose busulfan/thiotepa (HD-BuTT) with autologous peripheral blood stem-cell transplantation (aPBSCT) and response-adapted whole-brain radiation therapy (WBRT) in patients with newly diagnosed primary central nervous system lymphoma.

PATIENTS AND METHODS

Twenty-three patients were treated with HD-MTX on days 1 and 10. In case of at least a partial remission (PR), HD-BuTT followed by aPBSCT was given. Patients without response to induction or without complete remission (CR) after HD-BuTT received WBRT.

RESULTS

Sixteen patients received HD-MTX and HD-BuTT achieving a CR/PR rate of 69%/13%. CR/PR rates for all patients (n = 23) were 70%/13%. There were three deaths during therapy. With longer follow-up three neurotoxic deaths occurred in irradiated patients (n = 9), while no persistent neurotoxicity was seen after HD-BuTT without subsequent WBRT. At a median follow-up of 15 months (range 1-69) median event-free survival (EFS) and overall survival (OS) for all patients were 17 and 20 months (Kaplan-Meier), after HD-BuTT 27 months and "not reached", respectively. Estimated 2-year EFS and OS were 45% and 48% for all patients versus 56% and 61% for the HD-BuTT group, respectively.

CONCLUSION

MTX induction followed by HD-BuTT is an effective and very short time-on-treatment regimen. Median survival for patients treated with high-dose chemotherapy is not reached yet. The induction regimen needs optimisation. In this study WBRT was associated with a high incidence of severe neurotoxicity.

Methotrexate induces seizure and decreases glutamate uptake in brain slices: Prevention by ionotropic glutamate receptors antagonists and adenosine

Methotrexate (MTX)-induced neurotoxicity may occur after intrathecal or systemic administration at low, intermediate and high doses for the treatment of malignant or inflammatory diseases. The mechanisms of MTX neurotoxicity are not totally understood, and appear to be multifactorial. In this study we characterized a model of MTX-induced seizures in mice to evaluate the convulsive and toxic MTX properties. Additionally, the effect of MTX-induced seizures on the activity of glutamate transporters, as well as the anticonvulsant role of MK-801, DNQX and adenosine on glutamate uptake in brain slices was investigated . MTX induced tonic-clonic seizures in approximately 95% of animals and pre-treatment with MK-801, DNQX and adenosine prevented seizure in 80%, 62% and 50% of animals, respectively. Moreover, MTX leads 59% of mice to death, which was prevented in 100% and 94% when animals received MK-801 and DNQX, respectively. Glutamate uptake decreased by 20% to 30% in cortical slices after MTX-induced seizures. Interestingly, when seizures were prevented by MK-801, DNQX or adenosine, glutamate uptake activity remained at the same level as the control group. Thus, our results demonstrate the involvement of the glutamatergic system in MTX-induced seizures.

Neurological complications of cancer chemotherapy

PURPOSE OF REVIEW

To update central and peripheral nervous system neurological manifestations caused by anticancer agents.

RECENT FINDINGS

Mostly unpredictable encephalopathy continues to be sporadically reported even in patients treated systemically with conventional chemotherapy doses. Recently, capecitabine, a 5-fluorouracil prodrug, has been added to the list. Magnetic resonance diffusion-weighted and fluid-attenuated inversion-recovery imaging are useful in demonstrating chemotherapy-induced central nervous system lesions. The pathogenesis of these lesions is often poorly understood, and is probably multifactorial. A recent observation indicates that genetic polymorphism for methionine is a potent risk factor for methtrexate-induced central nervous system toxicity. Chronic peripheral neuropathy still represents a major limiting factor in a series of chemotherapeutic drugs, and the neuroprotective effect of several older and newer agents is either deceptive or insufficiently proven. In addition to chronic neuropathy, oxaliplatine causes a unique acute syndrome which may respond to calcium plus magnesium infusion.

SUMMARY

Neurotoxicity remains a major limitation of many drugs used in cancer patients. Their list grows steadily, and magnetic resonance imaging makes easier the recognition of central nervous system toxicity. Synthesis and thorough clinical testing of neuroprotective molecules remain a major challenge.

Clinical utility and pharmacology of high-dose methotrexate in the treatment of primary CNS lymphoma

Primary CNS non-Hodgkin lymphoma (PCNSL) has been shown to be increasing in incidence. This appears to be a consequence of the increasing population of those older than 65 years of age in whom PCNSL occurs most often. PCNSL often has a favorable response to treatment and aggressive management may result in extended survival and, in a proportion of patients less than 65 years of age, cure. The majority of neuro-oncologist's advocate utilizing high-dose methotrexate (HD-MTX) as a platform for the chemotherapy treatment of these neoplasms. In this review, the literature regarding HDHMTX as a treatment for PCNSL is summarized as are the pharmacological principles of HD-MTX.

The Activities of Antioxidant Enzymes and the Level of Malondialdehyde in Cerebellum of Rats Subjected to Methotrexate: Protective Effect of Caffeic Acid Phenethyl Ester

Methotrexate (MTX), a folic acid antagonist, is widely used as a cytotoxic chemotherapeutic agent. MTX-associated neurotoxicity is an important clinical problem. The aim of this study was to investigate the role of caffeic acid phenethyl ester (CAPE) on cerebellar oxidative stress induced by MTX in rats. A total of 19 adult male rats were divided into three experimental groups as follows: MTX group (MTX treated), MTX+CAPE group (MTX+CAPE treated), and control group. MTX was administered intraperitoneally (i.p.) with a single dose of 20 mg kg(-1) on the second day of experiment. CAPE was administered i.p. with a dose of 10 micromol kg(-1) day(-1) for 7 days. Malondialdehyde (MDA) levels and activities of superoxide dismutase (SOD) and catalase (CAT) were determined in cerebellar tissue of rats. MTX caused to significant increase in MDA levels (an important marker of lipid peroxidation) in the MTX group compared with the controls (p = 0.006). CAPE significantly reduced the MTX induced lipid peroxidation in the MTX+CAPE group compared to the MTX (p = 0.007). The activities of SOD and CAT were significantly increased in the MTX group when compared with the control group (p = 0.0001, p = 0.004, respectively). The increased activities of these enzymes were significantly reduced by CAPE treatment (p = 0.004, p = 0.034, respectively). As a result, CAPE may protect from oxidative damage caused by MTX treatment in rat cerebellum.

Update on primary central nervous system lymphoma

PURPOSE OF REVIEW

Primary central nervous system lymphoma is a rare form of extranodal non-Hodgkin's lymphoma that is confined to the central nervous system and eye. Numerous studies examining this disorder have been published in the past 2 years. This review will discuss recent advances in the understanding of the pathology, radiographic appearance, and treatment of this disorder.

RECENT FINDINGS

Novel treatment regimens continue to be studied for newly diagnosed and recurrent primary central nervous system lymphoma. As overall survival improves, the burden of late neurotoxicity has become more apparent. Neuropsychological testing of patients treated with chemoradiation shows significant cognitive deficits that can be attributed to whole brain irradiation. Standardization of phase II clinical trials across individual institutions remains an important goal within the oncology community. The International Primary Central Nervous System Lymphoma Collaborative Group (IPCG) has proposed guidelines for the baseline evaluation and response criteria for clinical trials of the disorder. In addition, series of patients with uncommon histological variants of primary central nervous system lymphoma have been published.

SUMMARY

In 2005, the optimal treatment for primary central nervous system lymphoma remains undefined. Treatment of newly diagnosed disease should include methotrexate-based chemotherapy but the role of irradiation and intrathecal chemotherapy remain unclear. Salvage therapy for progressive or recurrent primary central nervous system lymphoma is an area of active interest but no standard recommendations exist at the present time. Future studies on the biology of recurrent primary central nervous system lymphoma should help to clarify treatment options for these patients.

Homocysteine and folate metabolism in depression

Homocysteine is a sensitive marker of folate and vitamin B12 deficiency. Numerous studies have confirmed the association between folate deficiency and depression. It is not completely understood whether homocysteine is solely a marker for folate deficiency or if it may play a more direct role in the expression of mood disorders. This review describes the biochemical, neurochemical and clinical correlations of folate deficiency and hyperhomocysteinemia in relation to depression.