The Impact of Immunomodulatory Treatment on Kappa Free Light Chains as Biomarker in Neuroinflammation.

BACKGROUND: Kappa free light chains (KFLC) are a promising new biomarker to detect neuroinflammation. Still, the impact of pre-analytical effects on KFLC concentrations was not investigated. METHODS: KFLC concentrations were measured in serum and cerebrospinal fluid (CSF) of patients with a newly diagnosed multiple sclerosis (MS) or clinically isolated syndrome (CIS) before (n = 42) or after therapy with high-dose methylprednisolone (n = 65). In prospective experiments, KFLC concentrations were analyzed in the same patients in serum before and after treatment with high-dose methylprednisolone (n = 16), plasma exchange (n = 12), immunoadsorption (n = 10), or intravenous immunoglobulins (n = 10). In addition, the influence of storage time, sample method, and contamination of CSF with blood were investigated. RESULTS: Patients diagnosed with MS/CIS and treated with methylprednisolone showed significantly lower KFLC concentrations in serum as untreated patients. Repeated longitudinal investigations revealed that serum KFLC concentrations continuously decreased after each application of methylprednisolone. In contrast, other immune therapies and further pre-analytical conditions did not influence KFLC concentrations. CONCLUSION: Our results show prominent effects of steroids on KFLC concentrations. In contrast, various other pre-analytical conditions did not influence KFLC concentrations, indicating the stability of this biomarker.

Oxidative stress induced by lipid peroxidation is related with inflammation of demyelination and neurodegeneration in multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a chronic autoimmune demyelination disorder of the central nervous system (CNS) and its etiology remains unknown. The inflammatory environment in demyelinating lesions leads to the generation of oxygen- and nitrogen-free radicals as well as proinflammatory cytokines, which contribute to the development and progression of multiple sclerosis. Inflammation can lead to oxidative stress and vice versa. Thus, oxidative stress is involved in the inflammation leading demyelination and neurodegeneration in the pathogenesis of multiple sclerosis. SUMMARY: The present study aims to determine two biochemical markers of oxidative stress: TAC and MDA and to show their correlations whether oxidative stress reaction occurs in the demyelination through analyzing samples including peripheral blood and cerebrospinal fluid (CSF) from patients with relapsing-remitting MS (RR-MS). Totally, there were 20 patients in the control groups made from individuals with normal pressure hydrocephalus. Thirty MS patients diagnosed with McDonald diagnostic criteria (2010) treated with methylprednisolone were included in this study. Data were stratified by the degree of severity in order to clarify the role of oxidative stress in the mechanisms of MS and to assess its potential as a biomarker. Thirty clinically definite RRMS patients were enrolled in this study. Levels of MDA, GSH, total antioxidant capacity TAC, GSH-Px and ROS, were determined in serum of the control group and RRMS patients in 7 days before MP (methylprednisolone) treatment and one month after MP treatment. Statistical analysis was performed with one-way analysis of variance (ANOVA), followed by LSD's post hoc tests. KEY MESSAGES: Oxidative stress precedes the inflammatory response in the multiple sclerosis patients. And methylprednisolone treatment can decrease brain antioxidant enzymes to reduce the neuroinflammatory attack.

Cyclosporine-A-mediated inhibition of p-glycoprotein increases methylprednisolone entry into the central nervous system.

STUDY DESIGN: Prospective, randomized, pharmacokinetic study. OBJECTIVE: To determine if cyclosporine-A-mediated inhibition of p-glycoprotein would increase methylprednisolone entry into the central nervous system thereby permitting a reduction in the systemic methylprednisolone dose. SETTING: Department of Anesthesiology, University of Washington, Seattle, USA. METHODS: Microdialysis probes were used to obtain cerebrospinal fluid and gluteal muscle extracellular fluid samples for measurement of methylprednisolone concentration in pigs. At time zero, a methylprednisolone bolus was given and an infusion started. At 210 min, after reaching a stable methylprednisolone concentration, a cyclosporine-A bolus was given (either 10 or 30 mg/kg) and microdialysis samples collected until 420 min. Plasma samples were collected at 10, 30 min and then every 30 min until the study's end. RESULTS: Cyclosporine-A bolus produced a dose-dependant increase in methylprednisolone concentration in plasma, muscle and cerebrospinal fluid. Importantly, the magnitude of the increase in cerebrospinal fluid was significantly greater than the increase in plasma and muscle. CONCLUSIONS: The relatively greater increase in cerebrospinal fluid concentrations of methylprednisolone is consistent with increased penetration of the blood-brain barrier secondary to cyclosporine-mediated p-glycoprotein inhibition. Theoretically, increased methylprednisolone entry into the central nervous system should allow a reduction in the systemic methylprednisolone dose and a consequent decrease in glucocorticoid-mediated side effects.