Corticosteroid therapy exacerbates the reduction of melatonin in multiple sclerosis.

OBJECTIVES: Corticosteroid therapy is employed in multiple sclerosis (MS), a neurological abnormality characterized by an inflammatory process. Melatonin, a potent sleep-promoting and circadian phase regulatory hormone, is produced mainly in the pineal gland whose inhibition leads to sleep disturbances. METHODS: In this study, methylprednisolone (MP) corticosteroid treatment was used in an acute experimental autoimmune encephalomyelitis (EAE) rat model (intraperitoneal, 30 mg/kg) and in MS patients (intravenous, 1000 mg/day), followed by assessing melatonin serum levels. KEY FINDINGS: Results showed that mean clinical scores were significantly improved in MP- versus PBS-treated EAE rats (1.5 vs 4.1, respectively). In addition, MP was found to induce a significant decrease in serum IFN-γ, whereas IL-4 levels were significantly increased, in comparison to PBS-treated EAE rats. The ratio of IFN-γ/IL-4, which acts as an indicator of Th-1/Th-2, was significantly lower in MP treated, compared to PBS treated EAE rats or controls. Moreover, serum levels of melatonin showed a significant decrease in the MP group, compared to normal rats. Moreover, MP therapy for 1 or 2 days resulted in a significant reduction of melatonin serum levels in MS patients. CONCLUSIONS: Since corticosteroids cause a reduction in melatonin serum levels, an important hormone in sleep regulation, their prescription to MS patients should be carefully considered. Corticosteroids could be a cause of insomnia and sleep disturbance in patients receiving this type of medication.

Fluvoxamine stimulates oligodendrogenesis of cultured neural stem cells and attenuates inflammation and demyelination in an animal model of multiple sclerosis.

Multiple Sclerosis (MS) require medications controlling severity of the pathology and depression, affecting more than half of the patients. In this study, the effect of antidepressant drug fluvoxamine, a selective serotonin reuptake inhibitor, was investigated in vitro and in vivo. Nanomolar concentrations of fluvoxamine significantly increased cell viability and proliferation of neural stem cells (NSCs) through increasing mRNA expression of Notch1, Hes1 and Ki-67, and protein levels of NICD. Also, physiological concentrations of fluvoxamine were optimal for NSC differentiation toward oligodendrocytes, astrocytes and neurons. In addition, fluvoxamine attenuated experimental autoimmune encephalomyelitis (EAE) severity, a rat MS model, by significantly decreasing its clinical scores. Moreover, fluvoxamine treated EAE rats showed a decrease in IFN-γ serum levels and an increase in IL-4, pro- and anti-inflammatory cytokines respectively, compared to untreated EAE rats. Furthermore, immune cell infiltration and demyelination plaque significantly decreased in spinal cords of fluvoxamine-treated rats, which was accompanied by an increase in protein expression of MBP and GFAP positive cells and a decrease in lactate serum levels, a new biomarker of MS progression. In summary, besides its antidepressant activity, fluvoxamine stimulates proliferation and differentiation of NSCs particularly toward oligodendrocytes, a producer of CNS myelin.

Melatonin exacerbates acute experimental autoimmune encephalomyelitis by enhancing the serum levels of lactate: A potential biomarker of multiple sclerosis progression.

Melatonin has a beneficial role in adult rat models of multiple sclerosis (MS). In this study, melatonin treatment (10 mg/kg/d) was investigated in young age (5-6 weeks old) Lewis rat model of acute experimental autoimmune encephalomyelitis (EAE) followed by assessing serum levels of lactate and melatonin. Results showed that clinical outcomes were exacerbated in melatonin- (neurological score = 6) vs PBS-treated EAE rats (score = 5). Melatonin caused a significant increase in serum IFN-γ, in comparison to PBS-treated EAE rats whereas no considerable change in IL-4 levels were found, although they were significantly lower than those of controls. The ratio of IFN-γ/IL-4, an indicator of Th-1/Th-2, was significantly higher in PBS- and melatonin- treated EAE rats, in comparison to controls. Moreover, results showed increased lymphocyte infiltration, activated astrocytes (GFAP+ cells) but also higher demyelinated plaques (MBP-deficient areas) in the lumbar spinal cord of melatonin-treated EAE rats. Finally, serum levels of lactate, but not melatonin, significantly increased in the melatonin group, compared to untreated EAE and normal rats. In conclusion, our results indicated a relationship between age and the development of EAE since a negative impact was found for melatonin on EAE recovery of young rats by enhancing IFN-γ, the ratio of Th1/Th2 cells, and astrocyte activation, which seems to delay the remyelination process. While melatonin levels decline in MS patients, lactate might be a potential diagnostic biomarker for prediction of disease progression. Early administration of melatonin in the acute phase of MS might be harmful and needs further investigations.

Methylprednisolone improves lactate metabolism through reduction of elevated serum lactate in rat model of multiple sclerosis.

BACKGROUND: Some studies have demonstrated elevated concentrations of lactate both in the cerebrospinal fluid (CSF) and blood samples of multiple sclerosis (MS) patients as a pathological condition. We designed an experimental study first to investigate the serum level of lactate as a biomarker of MS progression and also to investigate the effect of methylprednisolone on serum lactate. METHODS: Experimental autoimmune encephalomyelitis (EAE) was inducted in Lewis rats, and then rats were treated intraperitoneally with methylprednisolone (30mg/kg/d), at the disease onset, and the clinical scores were recorded. After seven days of treatment, the serum levels of lactate were determined using high performance liquid chromatography (HPLC). Moreover, lymphocyte infiltration and the demyelinated area was analysed in spinal cord. RESULTS: Compared to the untreated-EAE rats, methylprednisolone remarkably improved the clinical score of EAE and ameliorated the spinal cord inflammation and demyelination. In addition, the marked decline in IFN-γ and the increase in IL-4 confirmed improvement in the rats treated with methylprednisolone. Measurement of lactate using HPLC indicated enhancement in the serum level of lactate in the untreated-EAE rats; the lactate level significantly decreased after methylprednisolone therapy. Moreover, serum lactates and disease severity were correlated positively and significantly. CONCLUSION: These data confirmed for the first time, that methylprednisolone can decreases the enhanced level of serum lactate in EAE model. In addition, it was shown that measurement of serum lactate could be an inexpensive and accurate laboratory test to determine the response to treatment and to assess disease severity in MS patients.