Immunoreactive leukotriene C4 levels in CSF of MS patients

The leukotriene receptor antagonist montelukast as a potential therapeutic adjuvant in multiple sclerosis - a review

Multiple Sclerosis (MS) is a multifactorial autoimmune disease of the central nervous system (CNS). It is characterized by a heightened activation of the immune system with ensuing inflammation, demyelination and neurodegeneration with consequences such as motor, sensory, cognitive, as well as autonomic dysfunctions. While a range of immune-modulatory drugs have shown certain efficacy in alleviating pathology and symptoms, none of the currently available therapeutics regenerates the damaged CNS to restore function. There is emerging evidence for leukotrienes and leukotriene receptors being involved in the various aspects of the MS pathology including neuroinflammation and de/remyelination. Moreover, leukotriene receptor antagonists such as the asthma drug montelukast diminish inflammation and promote regeneration/remyelination. Indeed, montelukast has successfully been tested in animal models of MS and a recent retrospective case-control study suggests that montelukast treatment reduces relapses in patients with MS. Therefore, we propose montelukast as a therapeutic adjuvant to the standard immune-modulatory drugs with the potential to reduce pathology and promote structural and functional restoration. Here, we review the current knowledge on MS, its pathology, and on the potential of leukotriene receptor antagonists as therapeutics for MS.

Role of T Lymphocytes in HIV Neuropathogenesis

PURPOSE OF REVIEW

The purpose of this review is to summarize the current knowledge on the role of CD4⁺ T lymphocytes leading to HIV assault and persistence in the central nervous system (CNS) and the elimination of HIV-infected CNS resident cells by CD8⁺ T lymphocytes.

RECENT FINDINGS

HIV targets the CNS early in infection, and HIV-infected individuals suffer from mild forms of neurological impairments even under antiretroviral therapy (ART). CD4⁺ T cells and monocytes mediate HIV entry into the brain and constitute a source for HIV persistence and neuronal damage. HIV-specific CD8⁺ T cells are also massively recruited in the CNS in acute infection to control viral replication but cannot eliminate HIV-infected cells within the CNS. This review summarizes the involvement of CD4⁺ T cells in seeding and maintaining HIV infection in the brain and describes the involvement of CD8⁺ T cells in HIV neuropathogenesis, playing a role still to be deciphered, either beneficial in eliminating HIV-infected cells or deleterious in releasing inflammatory cytokines.

Cysteinyl Leukotrienes as Potential Pharmacological Targets for Cerebral Diseases

Cysteinyl leukotrienes (CysLTs) are potent lipid mediators widely known for their actions in asthma and in allergic rhinitis. Accumulating data highlights their involvement in a broader range of inflammation-associated diseases such as cancer, atopic dermatitis, rheumatoid arthritis, and cardiovascular diseases. The reported elevated levels of CysLTs in acute and chronic brain lesions, the association between the genetic polymorphisms in the LTs biosynthesis pathways and the risk of cerebral pathological events, and the evidence from animal models link also CysLTs and brain diseases. This review will give an overview of how far research has gone into the evaluation of the role of CysLTs in the most prevalent neurodegenerative disorders (ischemia, Alzheimer's and Parkinson's diseases, multiple sclerosis/experimental autoimmune encephalomyelitis, and epilepsy) in order to understand the underlying mechanism by which they might be central in the disease progression.

G protein-coupled receptors as therapeutic targets for multiple sclerosis

G protein-coupled receptors (GPCRs) mediate most of our physiological responses to hormones, neurotransmitters and environmental stimulants. They are considered as the most successful therapeutic targets for a broad spectrum of diseases. Multiple sclerosis (MS) is an inflammatory disease that is characterized by immune-mediated demyelination and degeneration of the central nervous system (CNS). It is the leading cause of non-traumatic disability in young adults. Great progress has been made over the past few decades in understanding the pathogenesis of MS. Numerous data from animal and clinical studies indicate that many GPCRs are critically involved in various aspects of MS pathogenesis, including antigen presentation, cytokine production, T-cell differentiation, T-cell proliferation, T-cell invasion, etc. In this review, we summarize the recent findings regarding the expression or functional changes of GPCRs in MS patients or animal models, and the influences of GPCRs on disease severity upon genetic or pharmacological manipulations. Hopefully some of these findings will lead to the development of novel therapies for MS in the near future.

Temporal profiles of cerebrospinal fluid leukotrienes, brain edema and inflammatory response following experimental brain injury

The post-traumatic changes of leukotrienes LTC4, LTD4, LTE4, and LTB4 in cerebrospinal fluid of rats from 10 min to 7 days were investigated after controlled cortical impact in relation to brain edema and cellular inflammatory response. LTC4 increased five-fold at 4 h, normalized at 24 h, and showed another four-fold increase at 7 days. The same pattern was observed for LTD4 and LTE4. LTB4 however, behaved differently: concentrations were lower and levels peaked two-fold at 24 h. Edema in the injured hemisphere increased continuously up to 24 h without change contralaterally. Leukocyte infiltration, macrophage presence and microglia activation were most prominent at 24 h, 7 days and 24 h respectively. Leukotriene changes in CSF seem to reflect those in the affected tissue, with a time delay and in lower concentrations, and were not linearly correlated to brain edema. The initially high leukotriene levels are rather likely to contribute to the cytotoxic edema than to enhance a vasogenic edema component. The profile of LTB4 was parallel to the time course of leukocyte infiltration, indicating initiation of infiltration as well as prolonged production by leukocytes themselves. The second leukotriene peak at 7 days is likely to follow a different pathway and might be related to a production in macrophages or activated glia.

Leukotrienes in patients with clinically active multiple sclerosis

OBJECTIVES

The role of leukotrienes (LTs) in the pathophysiology of multiple sclerosis (MS) has been controversially discussed in the past. Studies of LTs in the cerebrospinal fluid (CSF) revealed different results mainly because of analytical difficulties.

MATERIAL AND METHODS

In the present study we used highly sensitive and specific analytical methods for measuring LTs in the CSF as well as in urine samples from 20 patients with active MS and 20 control patients with noninflammatory neurological disorders.

RESULTS

LTB4 concentrations in CSF were almost twice as high in MS patients compared with controls (P < 0.001). CSF concentrations of the cysteinyl-LTs (LTC4, LTD4 and LTE4) as well as urinary LTE4 showed no significant differences compared with controls (P > 0.05). In addition, there was no significant association between CSF pleocytosis, clinical severity or time of disease onset.

CONCLUSIONS

The increased concentration of LTB4 in the CSF of MS patients may indicate a biological importance for this mediator in MS.

Leukotriene B4 and C4 in cerebrospinal fluid from children with meningitis and febrile seizures

Concentrations of immunoreactive leukotriene C4 (LTC4) and leukotriene B4 (LTB4) in the cerebrospinal fluid from 18 patients with aseptic meningitis, including 2 patients with encephalitis and 4 patients with febrile seizures, were measured by a sensitive and specific radioimmunoassay; these results were compared with those from control subjects. The concentrations of both LTC4 and LTB4 were elevated significantly in patients with meningitis (LTC4: 115.6 +/- 47.7 pg/ml; LTB4: 1,603.0 +/- 273.5 pg/ml; n = 18) compared to controls (LTC4: 83.2 +/- 21.6 pg/ml; LTB4: 1,219.3 +/- 161.5 pg/ml; n = 12; P < .05 and P < .01, respectively). However, there was no significant increase in LT levels in patients with febrile seizures. These findings suggest that LTs may play an important role in the inflammatory response induced by viral infections of the central nervous system.