Giovanni Frisullo

Modulation of LTP at rat hippocampal CA3-CA1 synapses by direct current stimulation

Transcranial direct current stimulation (tDCS) can produce a lasting polarity-specific modulation of cortical excitability in the brain, and it is increasingly used in experimental and clinical settings. Recent studies suggest that the after-effects of tDCS are related to molecular mechanisms of activity-dependent synaptic plasticity. Here we investigated the effect of DCS on the induction of one of the most studied N-methyl-d-aspartate receptor-dependent forms of long-term potentiation (LTP) of synaptic activity at CA3-CA1 synapses in the hippocampus. We show that DCS applied to rat brain slices determines a modulation of LTP that is increased by anodal and reduced by cathodal DCS. Immediate early genes, such as c-fos and zif268 (egr1/NGFI-A/krox24), are rapidly induced following neuronal activation, and a specific role of zif268 in the induction and maintenance of LTP has been demonstrated. We found that both anodal and cathodal DCS produce a marked subregion-specific increase in the expression of zif268 protein in the cornus ammonis (CA) region, whereas the same protocols of stimulation produce a less pronounced increase in c-fos protein expression in the CA and in dentate gyrus regions of the hippocampus. Brain-derived neurotrophic factor expression was also investigated, and it was found to be reduced in cathodal-stimulated slices. The present data demonstrate that it is possible to modulate LTP by using DCS and provide the rationale for the use of DCS in neurological diseases to promote the adaptive and suppress the maladaptive forms of brain plasticity.

pSTAT1, pSTAT3, and T-bet expression in peripheral blood mononuclear cells from relapsing-remitting multiple sclerosis patients correlates with disease activity.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system, and it is considered to be a T helper 1 (Th1) cell‐mediated autoimmune disease. T‐bet has been identified as a key transcription factor for the development of Th1 cells and the induction of interferon (IFN)‐γ production. T‐bet is induced during T‐cell activation by the IFN‐γ signal transducer and activator of transcription (STAT)‐1 signalling pathway. In this study we found an up‐regulation of T‐bet and pSTAT1 in peripheral blood CD4+ and CD8+ T cells and monocytes from relapsing‐remitting MS patients in relapse compared with patients in remission and with healthy subjects. The increased expression of pSTAT1 strongly correlated with T‐bet expression in CD4+ and CD8+ cells and monocytes from patients in relapse and was associated with an increased production of IFN‐γ by peripheral blood mononuclear cells (PBMCs). pSTAT3 was also up‐regulated in CD4+ and CD8+ cells and monocytes from patients in relapse and was associated with an increased production of interleukin (IL)‐10 but not of IL‐6. pSTAT1, pSTAT3, and T‐bet expression strongly correlated with Gd‐DTPA‐enhanced lesions on brain and spinal cord magnetic resonance imaging. Our data show for the first time that there is an up‐regulation of type 1 immunity‐correlated transcription factors such as STAT1 and T‐bet in peripheral blood subpopulations of MS patients in the active phase of disease. The evaluation of T‐bet and pSTAT1 expression in peripheral blood CD4+, CD8+ T cells and monocytes could be used as a marker of disease activity in relapsing‐remitting MS.

Leptin as a marker of multiple sclerosis activity in patients treated with interferon-beta

The role of leptin was investigated in relapsing-remitting multiple sclerosis (MS). Control and MS patients showed comparable baseline serum leptin levels. During the first year of IFNbeta-1a treatment, leptin significantly decreased since 2 months after starting therapy in 11 patients who had no relapses. A significant decrease in IL12/IL10 ratio was observed in this group of patients only after 1 year of treatment. An increase of leptin was observed before the first clinical exacerbation in 13 relapsing patients. Leptin may play a pathogenic role in MS and can be a useful marker of disease activity and response to therapy.

Correlations between peripheral blood mononuclear cell production of BDNF, TNF-alpha, IL-6, IL-10 and cognitive performances in multiple sclerosis patients.

The aim of this study was to investigate the role of Brain Derived Neurotrophic Factor (BDNF) and inflammatory factors in the development of cognitive dysfunctions in Multiple Sclerosis (MS). We correlated peripheral blood mononuclear cell (PBMC) production of BDNF, Tumor Necrosis Factor‐alpha (TNF‐α), Interleukin (IL)‐6 and IL‐10 with performances on specific neuropsychological tasks in a selected series of MS patients. We studied a sample of 30 patients with relapsing‐remitting (RR)MS, segregated by gender and matched for age, education, disease duration, type of immunomodulating therapy, degree of disability and overall cognitive status. We found that low BDNF levels were correlated with increased time of execution on a divided attention and visual scanning task whereas high levels of IL‐6 were correlated with low Mini Mental State Examination scores. We did not observe any significant correlations between IL‐10, TNF‐α levels and cognitive performances in our patients. In conclusion our study shows a correlation between low BDNF and high IL‐6 production by PBMCs and poorer performances in cognitive tasks in RRMS patients suggesting a possible role of these factors in cognitive impairment in MS.

Regulatory T cells fail to suppress CD4+T-bet+ T cells in relapsing multiple sclerosis patients

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system and a defect in the regulatory T‐cell subset seems to be involved in the pathogenesis of the disease. Foxp3 is a transcription factor that is selectively expressed in CD4+ CD25+ regulatory T cells and is required for their development and function. T‐bet is a key transcription factor for the development of T helper 1 (Th1) cells. We found that both the percentage of circulating CD4+ CD25+ Foxp3+ cells and Foxp3 expression were lower in relapsing‐remitting (RR) MS patients during relapses than during remission. Otherwise, the percentage of CD4+ T‐bet+ T cells and T‐bet expression in CD4+ T cells were higher in relapsing than in remitting RRMS patients. CD4+ CD25+ T cells both from relapsing and from remitting RRMS patients showed significantly less capacity than corresponding cells from healthy subjects to suppress autologous CD4+ CD25− T‐cell proliferation, despite a similar Foxp3 expression level. CD4+ CD25+ T cells from healthy subjects and patients in remission clearly reduced T‐bet mean fluorescence intensity (MFI) in CD4+ CD25− T cells up to a ratio of 1:10, whereas CD4+ CD25+ T cells from patients in relapse were able to reduce T‐bet expression only at a high ratio. Our data indicate that the increased number of regulatory T (T‐reg) cells and the increased Foxp3 expression in circulating CD4+ CD25+ T cells may contribute to the maintenance of tolerance in the remission phase of MS. Moreover, the inhibitory capacity of CD4+ CD25+ T cells seems to be impaired in relapsing patients under inflammatory conditions, as shown by the high levels of T‐bet expression in CD4+ T cells.

IL17 and IFNgamma production by peripheral blood mononuclear cells from clinically isolated syndrome to secondary progressive multiple sclerosis.

We evaluated the spontaneous IL17, IFNgamma and IL10 production by peripheral blood mononuclear cells from patients affected by clinically isolated syndromes (CIS) suggestive of multiple sclerosis (MS) both in acute phase and in remission, relapsing remitting MS (RRMS) both in relapse and in remission, not-relapsing secondary progressive MS (SPMS) and controls. We observed higher IL17 levels in CIS patients both in acute phase and in remission than in SPMS patients and controls. On the contrary no difference in IL17 production was observed among RRMS patients and CIS, SPMS patients and controls. IFNgamma levels were significantly higher in CIS patients in acute phase than in CIS and RRMS patients in remission, SPMS patients and controls. Moreover, we observed higher IFNgamma spontaneous production in relapsing RRMS patients than in remitting RRMS and SPMS patients and controls. IL10 levels were significantly higher in remitting CIS and in relapsing RRMS patients than in SPMS patients and controls. There was no difference in IFNgamma, IL10 and IL17 levels between SPMS patients and controls. Our data suggest that IL17 might play a crucial role mainly in the early phase of MS, while IFNgamma seems to be involved both in the early phase and in the following relapses of the disease.

Neurotrophic factors and clinical recovery in relapsing-remitting multiple sclerosis.

Pathogenic autoimmune cells are demonstrated to be able to produce neurotrophic factors during acute phase of multiple sclerosis (MS). In this study, we determined the production of various neurotrophins [brain‐derived neurotrophic factor (BDNF), nerve growth factor (NGF), glial cell line‐derived neurotrophic factor (GDNF), neurotrophin 3 (NT3) and neurotrophin 4 (NT4)] and some pro‐inflammatory cytokines [tumour necrosis factor‐α (TNF‐α) and interferon‐γ (IFN‐γ)] by unstimulated peripheral blood mononuclear cells (PBMC) in 21 relapsing‐remitting MS patients during different phases of disease (stable, relapse and post‐relapse). During acute phase of disease, we detected a considerable increase of BDNF, TNF‐α and IFN‐γ production, while significantly higher levels of GDNF, NGF, NT3 and NT4 were found in post‐relapse phase. When neurotrophin production was correlated with clinical outcome (complete or partial recovery from new symptoms), we found a significantly higher BDNF production in relapse phase followed by increased GDNF, NGF, NT3 and NT4 levels during post‐relapse phase in subjects with complete remission only. During relapse phase, we detected a significant increase of pro‐inflammatory cytokines, that was more evident in patients with partial recovery. The neuroprotective potential of immune cells seems to be inversely correlated with disease duration and with the age of patients.

CD8(+)Foxp3(+) T cells in peripheral blood of relapsing-remitting multiple sclerosis patients.

A defect of CD4(+) regulatory T cells (Treg) seems to be involved in the pathogenesis of multiple sclerosis (MS). Besides Treg, CD8(+) T cells also can suppress the immune response. Forkhead box p3 (Foxp3) is known to program the acquisition of suppressive capacities in CD4(+) T cells and recent studies showed that in vitro antigen activation leads to Foxp3 expression in CD8(+) T cells, gaining of suppressive activity. By flow cytometry we found a lower percentage of circulating CD8(+)Foxp3(+) T cells in relapsing than in remitting patients with MS and in controls. No significant differences were observed in CD8(+)Foxp3(+) T cell percentage between healthy subjects and patients in remission. Our data suggest that peripheral CD8(+)Foxp3(+) T cells may play a role in the maintenance of tolerance in MS.

Acute Necrotizing Encephalopathy during Novel Influenza A (H1N1) Virus Infection

A novel swine‐origin influenza A (H1N1) virus was recently identified in Mexico. Some cases of infection with neurological complications have been reported to date. We report a case of acute necrotizing encephalopathy associated with the novel H1N1 virus in a 2‐year‐old European girl who suddenly developed fever, seizures, and altered mental status. Brain and spinal cord magnetic resonance imaging showed bilateral symmetrical lesions of the insulae, thalami, geniculate bodies, and pons tegmentum suggestive of an acute necrotizing encephalopathy. An involvement of meninges and spinal cord was observed configuring an acute necrotizing meningoencephalomyelitis. ANN NEUROL 2010;68:111–114

Increased CD4(+)CD25(+)Foxp3(+) T Cells in Peripheral Blood of Celiac Disease Patients: Correlation with Dietary Treatment.

Regulatory CD4+ CD25+Foxp3+ T cells are involved in the regulation of immune response and inhibit protective antitumor immunity. Celiac disease (CD), a food gluten-sensitive enteropathy, is considered a T-cell-mediated autoimmune disease and is generally associated with an overall increased risk of cancer in CD patients. We observed a higher percentage of circulating CD4+CD25+Foxp3+ T cells and an increased Foxp3 expression in CD4+CD25+ T cells from untreated than from treated CD patients. In co-culture, CD4+CD25+ T cells from both treated and untreated CD patients significantly suppressed the proliferation of autologous CD4+CD25(-) T cells similarly to values in healthy subjects. Our study suggests that Treg proportion and Foxp3 expression in circulating CD4+CD25+ T cells could justify the increased global risk of malignancy in CD population and support the efficacy of lifelong gluten-free diet in the reduction of the cancer risk.