Pachymeningeal involvement in POEMS syndrome: MRI and histopathological study.

Polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, skin changes (POEMS) syndrome is a rare plasma cell disease. Vascular endothelial growth factor (VEGF) seems to play a pathogenic role. Peripheral neuropathy is the main neurological feature. Cranial pachymeningitis has occasionally been reported, but no histopathological studies have been performed. The authors extensively evaluated the central nervous system MRI in 11 patients (seven men, four women; mean age at diagnosis 54.45 years) with POEMS syndrome. In two patients, meningeal histopathology with staining for VEGF and VEGF receptor was performed, and pachymeningeal involvement characterised at histopathological, immunohistochemical and confocal microscopy levels. Nine patients presented with cranial pachymeningitis. One patient suffered from migraine, and none complained of cranial nerve palsies or visual loss. None showed any MRI signs of spinal pachymeningitis. No correlation was found with disease duration and VEGF serum level. Histopathology showed hyperplasia of meningothelial cells, neovascularisation and obstructive vessel remodelling, without inflammation. VEGF and VEGF receptor were strongly coexpressed on endothelium, smooth-muscle cells of arterioles and meningothelial cells. In conclusion, POEMS patients present a high prevalence of meningeal involvement. The histological changes, different from those present in chronic pachymeningitis of other aetiology, suggest a possible VEGF role in the pathogenesis of the meningeal remodelling.

Induction of the unfolded protein response by α-synuclein in experimental models of Parkinson's disease.

Accumulation of misfolded proteins in the endoplasmic reticulum (ER) is the main event leading to the induction of the ER stress-related unfolded protein response (UPR). Recent postmortem evaluation, showing that the UPR pathway is activated in nigral dopaminergic neurons bearing α-synuclein inclusions in the brain of Parkinson's disease (PD) patients, suggests that the activation of the UPR may be induced by the accumulation of α-synuclein. In this study, we show that the misfolded protein-sensor/UPR activator glucose-regulated protein 78/immunoglobulin heavy chain-binding protein was bound to α-synuclein and was increased in 'in vitro' and 'in vivo' models showing aggregated α-synuclein accumulation. Moreover, α-synuclein accumulation induced the expression of the UPR-related activating transcription factor 4/cAMP-responsive element-2. These findings indicate that activation of the UPR pathway in the PD brain is associated with α-synuclein accumulation occurring in part within the ER.

Safety of Cerebrolysin for Neurorecovery after Acute Ischemic Stroke: A Systematic Review and Meta-Analysis of Twelve Randomized-Controlled Trials.

We performed a systematic search and meta-analysis of available literature to determine the safety profile of Cerebrolysin in acute ischemic stroke, filling existing safety information gaps and inconsistent results. We searched EMBASE, PubMed, and Cochrane Databases of Systematic Reviews and Clinical Trials up to the end of February 2021. Data collection and analysis were conducted using methods described in the Cochrane Handbook for Systematic Reviews of Interventions. All safety outcomes were analyzed based on risk ratios (RR) and their 95% confidence intervals. The meta-analysis pooled 2202 patients from twelve randomized clinical trials, registering non-statistically significant (p > 0.05) differences between Cerebrolysin and placebo throughout main and subgroup analyses. The lowest rate of Serious Adverse Events (SAE), as compared to placebo, was observed for the highest dose of Cerebrolysin (50 mL), highlighting a moderate reduction (RR = 0.6). We observed a tendency of superiority of Cerebrolysin regarding SAE in high dose treatment courses for moderate-severe ischemic stroke, suggesting some effect of the agent against adverse events. This comprehensive safety meta-analysis confirms the safety profile for patients treated with Cerebrolysin after acute ischemic stroke, as compared to placebo.

Vascular cognitive disorder. A biological and clinical overview.

Although vascular dementia (VaD) represents the second most common cause of dementia after Alzheimer's disease (AD) in the elderly, and is referred as the "silent epidemic of the twenty-first century", there is still a controversy on terminology, classification and diagnostic criteria of VaD. The diagnosis of VaD resides in clinical criteria determining a cognitive impairment, the presence of cerebrovascular disease and, only in the case of post-stroke dementia or multi-infarct dementia, a temporal relationship between these. The search for a reliable biochemical tests helping in the diagnosis of VaD is so far not available. Several vascular risk factors have a role in the development of VaD and their identification and treatment are among the major aspects of management of VaD. A new line of research in this field is the study of genetic factors underlying vascular cognitive impairment which are: (1) genes predisposing to cerebrovascular disease, and (2) genes that influence brain tissue responses to cerebrovascular lesions. Evidence in favour of a coexistence of vascular and degenerative components in the pathogenesis of dementia in an elderly population comes from neuropathological and epidemiological studies. There is now a great debate whether VaD and AD are more than common coexisting unrelated pathologies and, instead, represent different results of synergistic pathological mechanisms. Preventive approaches aiming at reducing incident VaD by targeting patients at risk of cerebrovascular disease (primary prevention), or acting on patients after a stroke (secondary prevention) to prevent stroke recurrence and the progression of brain changes associated with cognitive impairment are mandatory therapeutic strategies.

Anti-ganglioside autoantibodies in type 1 diabetes.

Type 1 diabetes is an autoimmune disease that is accompanied by an immune response against pancreatic cells. As gangliosides are expressed in both peripheral nerves and pancreatic cells, we examined the possibility of correlation between type 1 diabetes, anti-ganglioside autoantibodies, and neuropathy. Fifty diabetic patients and 30 controls with other autoimmune diseases underwent neurological examination and search for antibodies to gangliosides, glutamic acid decarboxylase (GAD(65)), and tyrosine phosphatase (IA2). Sixteen (32%) diabetic patients had neuropathy. Twelve diabetic sera were found to have anti-ganglioside autoantibodies. Twenty sera were positive for anti-GAD(65) and nine for anti-IA2 antibody. Sera from three control patients had anti-ganglioside autoantibodies. No significant correlation was found between autoantibodies, neuropathy, and disease duration. Disease duration was shorter in patients with antibodies to GAD(65) and IA2 and longer in neuropathic patients. The higher prevalence of antibodies in diabetic patients compared to controls may reflect the common pattern of antigens shared by peripheral nerve and pancreatic islet cells.

NF-kappaB p50/RelA and c-Rel-containing dimers: opposite regulators of neuron vulnerability to ischaemia.

Diverse nuclear factor-kappaB subunits mediate opposite effects of extracellular signals on neuron survival. While RelA is activated by neurotoxic agents, c-Rel drives neuroprotective effects. In brain ischaemia RelA and p50 factors rapidly activate, but how they associate with c-Rel to form active dimers and contribute to the changes in diverse dimer activation for neuron susceptibility is unknown. We show that in both cortical neurons exposed to oxygen glucose deprivation (OGD) and mice subjected to brain ischaemia, activation of p50/RelA was associated with inhibition of c-Rel/RelA dimer and no change p50/c-Rel. Targeting c-Rel and RelA expression revealed that c-Rel dimers reduced while p50/RelA enhanced neuronal susceptibility to anoxia. Activation of p50/RelA complex is known to induce the pro-apoptotic Bim and Noxa genes. We now show that c-Rel-containing dimers, p50/c-Rel and RelA/c-Rel, but not p50/RelA, promoted Bcl-xL transcription. Accordingly, the OGD exposure induced Bim, but reduced Bcl-xL promoter activity and decreased the content of endogenous Bcl-xL protein. These findings demonstrate that within the same neuronal cell, the balance between activation of p50/RelA and c-Rel-containing complexes fine tunes the threshold of neuron vulnerability to the ischaemic insult. Selective targeting of different dimers will unravel new approaches to limit ischaemia-associated apoptosis.

Alpha-synuclein aggregation and cell death triggered by energy deprivation and dopamine overload are counteracted by D2/D3 receptor activation.

Progressive degeneration and intraneuronal Lewy bodies made of filamentous alpha-synuclein (alpha-syn) in dopaminergic cells of the nigrostriatal system are characteristics of Parkinson's disease (PD). Glucose uptake is reduced in some of the brain regions affected by PD neurodegenerative changes. Defects in mitochondrial activity in the substantia nigra have been observed in the brain of patients affected by PD and substantia nigra lesions can induce the onset of a secondary parkinsonism. Thus, energy starvation and consequently metabolic impairment to dopaminergic neurons may be related to the onset of PD. On this line, we evaluated the effect of nutrient starvation, reproduced 'in vitro' by glucose deprivation (GD), in primary mesecephalic neuronal cultures and dopaminergic-differentiated SH-SY5Y cells, to evaluate if decreased glucose support to dopaminergic cells can lead to mitochondrial damage, neurodegeneration and alpha-syn misfolding. Furthermore, we investigated the effect of dopamine (DA) treatment in the presence of a DA-uptake inhibitor or of the D(2)/D(3) receptor (D(2)R/D(3)R) agonist quinpirole on GD-treated cells, to evaluate the efficacy of these therapeutic compounds. We found that GD induced the formation of fibrillary aggregated alpha-syn inclusions containing the DA transporter in dopaminergic cells. These alterations were accompanied by dopaminergic cell death and were exacerbated by DA overload. Conversely, the block of DA uptake and D(2)R/D(3)R agonist treatment exerted neuroprotective effects. These data indicate that glucose starvation is likely involved in the induction of PD-related pathological changes in dopaminergic neurons. These changes may be counteracted by the block of DA uptake and by dopaminergic agonist treatment.

Neurological complications of celiac disease and autoimmune mechanisms: a prospective study.

Humoral immune mechanisms may have a role in the neurological complications of celiac disease (CD). We assessed 71 CD patients for neurologic manifestations and presence of serum antibodies to neural antigens. Sixteen patients (22.5%) were found to have neurological deficits including headache, depression, entrapment syndromes, peripheral neuropathy, and epilepsy. Antibody reactivity to neural antigens was detected in 30/71 (42.2%) patients. There was no clear correlation between anti-neural reactivity and neurologic dysfunction. Follow-up of 62 patients did not reveal change in electrophysiology or antibodies, regardless of diet. However, in 2 patients with neuropathy, symptoms improved or worsened depending on the diet.

Extensive cortical inflammation is associated with epilepsy in multiple sclerosis.

INTRODUCTION: Epilepsy is three to six times more frequent in MS than in the general population. Previous studies based on conventional magnetic resonance (MR) imaging have suggested a possible correlation between cortical inflammatory pathology and epileptic seizures. However, pure intracortical lesions (ICLs) are unlikely to be demonstrated with conventional MR. We applied the double inversion recovery (DIR) sequence in relapsing remitting MS (RRMS) patients with or without epileptic seizures in order to clarify the relationship between ICLs and epilepsy in MS in vivo. METHODS: Twenty RRMS patients who had epileptic seizures (RRMS/E) during the course of the disease were studied for the presence of ICLs. A group of 80 RRMS patients with no history of seizures and matched for gender, age, disease duration, Expanded Disability Status Scale (EDSS) grading, and T2 lesion volume (T2-WMLV) was selected as reference population. ICLs were detected by applying the DIR sequence. RESULTS: ICLs were observed in 18/20 (90%) RRMS/E and in 39/80 (48%) RRMS (p = 0.001). RRMS/E showed five times more ICLs (7.2 +/- 8.4) than RRMS (1.5 +/- 2.4; p = 0.015). The total ICLs volume was 6 times larger in RRMS/E than in RRMS (1.2 +/- 1.7 cm3 versus 0.2 +/- 0.2 cm3, p = 0.016). No significant difference was observed between RRMS and RRMS/E with regard to the number and volume of juxtacortical lesions and T2-WMLV. DISCUSSION: Our findings indicate that RRMS/E have more extensive cortical inflammation than RRMS patients with no history of epilepsy. Inflammatory ICLs may be responsible for epilepsy in MS.

Cannabidiol, unlike synthetic cannabinoids, triggers activation of RBL-2H3 mast cells.

Cannabidiol (CBD), a prominent psychoinactive component of cannabis with negligible affinity for known cannabinoid receptors, exerts numerous pharmacological actions, including anti-inflammatory and immunosuppressive effects, the underlying mechanisms of which remain unclear. In the current study, we questioned whether CBD modulates activation of mast cells, key players in inflammation. By using the rat basophilic leukemia mast cell line (RBL-2H3), we demonstrate that CBD (3-10 muM) augments beta-hexosaminidase release, a marker of cell activation, from antigen-stimulated and unstimulated cells via a mechanism, which is not mediated by G(i)/G(o) protein-coupled receptors but rather is associated with a robust rise in intracellular calcium ([Ca(2+)](i)) levels sensitive to clotrimazole and nitrendipine (10-30 muM). This action, although mimicked by Delta(9)-tetrahydrocannabinol (THC), is opposite to that inhibitory, exerted by the synthetic cannabinoids WIN 55,212-2 and CP 55,940. Moreover, the vanilloid capsaicin, a full agonist of transient receptor potential channel VR1, did not affect [Ca(2+)](i)levels in the RBL-2H3 cells, thus excluding the involvement of this receptor in the CBD-mediated effects. Together, these results support existence of yet-to-be identified sites of interaction, i.e., receptors and/or ion channels associated with Ca(2+) influx of natural cannabinoids such as CBD and THC, the identification of which has the potential to provide for novel strategies and agents of therapeutic interest.

Detection of cortical inflammatory lesions by double inversion recovery magnetic resonance imaging in patients with multiple sclerosis.

BACKGROUND: A significant inflammatory pathologic disorder in the cortex of patients with multiple sclerosis (MS) has been demonstrated by ex vivo studies. OBJECTIVE: To determine the frequency, time of appearance, and clinical relevance of intracortical lesions (ICLs) in MS in vivo. DESIGN: Double inversion recovery sequence study. SETTING: Multiple Sclerosis Centre of the Veneto Region. Patients We enrolled 380 patients (116 with clinically isolated syndrome [CIS], 163 with relapsing-remitting MS [RRMS], and 101 with secondary progressive MS [SPMS]) and 40 age- and sex-matched healthy volunteers between May 1, 2005, and December 31, 2006. MAIN OUTCOME MEASURES: We assessed the frequency and number of ICLs and brain parenchyma fraction, white matter T2 lesion volume, and clinical disability. RESULTS: Although never observed in healthy volunteers, ICLs were detected in 58% of patients (36% of patients with CIS, 64% of patients with RRMS, and 73% of patients with SPMS). The number of ICLs was higher in patients with SPMS than in those with CIS or RRMS (P <.001), and patients with ICLs had a higher Expanded Disability Status Scale score (P = .004), a higher white matter T2 lesion volume (P = .008), a lower brain parenchyma fraction (P = .009), and a higher frequency of IgG oligoclonal bands (IgGOBs) (P <.001) than patients without ICLs. Patients positive for IgGOBs had more ICLs than patients negative for IgGOBs (P = .02). The number of ICLs correlated with the Expanded Disability Status Scale score (r = 0.48, P <.001), white matter T2 lesion volume (r = 0.38, P = .001), and brain parenchyma fraction (r = -0.47, P = .001). A significant association between ICLs and male sex was observed. CONCLUSIONS: Although more frequent in patients with SPMS, ICLs were observed from the early disease stages. The ICLs were more frequently detected in patients with IgGOBs and were associated with a higher clinical disability score and male sex. The ICLs may help to define MS clinical heterogeneity and prognosis in clinical settings.

Cortical atrophy is relevant in multiple sclerosis at clinical onset.

INTRODUCTION: Increasing evidence suggests relevant cortical gray matter pathology in patients with Multiple Sclerosis (MS), but how early this pathology begins; its impact on clinical disability and which cortical areas are primarily affected needs to be further elucidated. METHODS: 115 consecutive patients (10 Clinically Isolated Syndrome (CIS), 32 possible MS (p-MS), 42 Relapsing Remitting MS (RR-MS), 31 Secondary Progressive MS (SP-MS)), and 40 age/gender-matched healthy volunteers (HV) underwent a neurological examination and a 1.5 T MRI. Global and regional Cortical Thickness (CTh) measurements, brain parenchyma fraction and T2 lesion load were analyzed. RESULTS: We found a significant global cortical thinning in p-MS (2.22 +/- 0.09 mm), RR-MS (2.16 +/- 0.10 mm) and SP-MS (1.98 +/- 0.11 mm) compared to CIS (2.51 +/- 0.11 mm) and HV (2.48 +/- 0.08 mm). The correlations between mean CTh and white matter (WM) lesion load was only moderate in MS (r = -0.393, p = 0.03) and absent in p-MS (r = -0.147, p = 0.422). Analysis of regional CTh revealed that the majority of cortical areas were involved not only in MS, but also in p-MS. The type of clinical picture at onset (in particular, pyramidal signs/symptoms and optic neuritis) correlated with atrophy in the corresponding cortical areas. DISCUSSION: Cortical thinning is a diffuse and early phenomenon in MS already detectable at clinical onset. It correlates with clinical disability and is partially independent from WM inflammatory pathology.

Mitoxantrone versus cyclophosphamide in secondary-progressive multiple sclerosis: a comparative study.

Fifty secondary progressive multiple sclerosis (SPMS) patients who had lost one or more EDSS points in the prior two years were selected to receive either cyclophosphamide (25 patients, 13 females, 12 males, F/M = 1.08; mean age: 42.4 years; mean disease duration: 13.3 years; mean EDSS at study entry: 5.7) or mitoxantrone (25 patients, 14 females, 11 males, F/M = 1.27; mean age: 38.2 years; mean disease duration: 11.5 years; mean EDSS at study entry: 5.5). SPMS patients were treated for two years with clinical evaluation (relapse rate, disability progression) every three months and radiological imaging (conventional magnetic resonance imaging) before therapy initiation and at the end of the first and second years of therapy. Safety profile and costs of the two therapeutic protocols were also analysed. In terms of clinical and radiological measures the drugs exerted a quite identical effect on both, and produced a significant reduction in both relapse rate (mitoxantrone Mito): p = 0.001, cyclophosphamide (Cy): p = 0.003) and disability progression (Mito: p = 0.01; Cy: p = 0.01). Subgroups of mitoxantrone- and cyclophosphamide-responding patients were identified (14/25 and 17/25, respectively) and were characterized by a significantly shorter duration of the secondary progressive phase of the disease. In these subgroups, the improvement in the EDSS score at the end of therapy was highly significant (p<0.0001 for Mito, p = 0.0004 for Cy). The safety profiles of both drugs were acceptable; however, the Cy-based therapy protocol was significantly less expensive. We conclude that Cy should be considered as a therapeutic option in rapidly deteriorating SPMS patients.

Multiple sclerosis and autoimmune diseases: epidemiology and HLA-DR association in North-east Italy.

An autoimmune background is thought to characterize the families of multiple sclerosis (MS) patients, but disease patterns and HLA-DR association seem to vary considerably among different ethnic groups. We investigated the prevalence of autoimmune diseases in 245 MS patients and 245 age- and sex-matched normal controls (NC), originating from and living in North-east Italy, and their first degree relatives, using a case-control method. Further, HLA-DRB1 expression was analysed in MS and NC. The following significant findings were observed: 1) a significant excess of autoimmunity in first-degree relatives of MS patients (p = 0.000), 2) an association of MS with Type 1 diabetes mellitus (T1DM) (p = 0.02), 3) an increase in DR4 expression (namely DRB1*0401) in MS patients from families with multiple autoimmune pathology compared with reference MS patients (p=0.02) and NC (p=0.01). We conclude that the risk of autoimmune disease is higher in first-degree relatives of MS patients and that disease association and HLA-DR expression in North-east Italy differs from other geographic regions of Europe.

Anti-heparan sulphate antibodies and homocysteine in dementia: markers of vascular pathology?

Increasing evidence supports a pathogenic role of heparan sulphate (HS) in the development of dementia. Since HS proteoglycans are present in the endothelial cells and perivascular basement membrane, we wanted to assess blood titres of HS antibodies (Abs) in patients with vascular dementia (VD) and in patients with Alzheimer's disease (AD) with cerebrovascular disease (CVD) [mixed dementia (MixD)]. Moreover, plasma levels of homocysteine, an independent risk factor for the development of dementia as well as for CVD, were also determined. High HS Abs titres were present in one patient with VD and in two patients with mixed dementia, as well as in two neurological control patients (stroke and epilepsy). Increased homocysteine levels were found in 62.5% of patients with mixed dementia, in 22.2% of the VD subjects, in 54.2% of patients with CVD, and in 41.2% of patients with other neurological diseases. The present findings suggest that neither elevated HS Abs titres nor increased homocysteinemia may represent a useful biochemical marker for the diagnosis of VD.

[1-13C]Glucose entry in neuronal and astrocytic intermediary metabolism of aged rats. A study of the effects of nicergoline treatment by 13C NMR spectroscopy.

Age-related changes in glucose utilization through the TCA cycle were studied using [1-13C]glucose and 13C, 1H NMR spectroscopy on rat brain extracts. Significant increases in lactate levels, as well as in creatine/phosphocreatine ratios (Cr/PCr), and a decrease in N-acetyl-aspartate (NAA) and aspartate levels were observed in aged rat brains as compared to adult animals following glucose administration. The total amount of 13C from [1-13C]glucose incorporated in glutamate, glutamine, aspartate and GABA was significantly decreased in control aged rat brains as compared to adult brains. The results showed a decrease in oxidative glucose utilization of control aged rat brains. The long-term nicergoline treatment increased NAA and glutamate levels, and decreased the lactate levels as well as the Cr/PCr ratios in aged rat brains as compared to adult rats. The total amount of 13C incorporated in glutamate, glutamine, aspartate, NAA and GABA was increased by nicergoline treatment, showing an improvement in oxidative glucose metabolism in aged brains. A significant increase in pyruvate carboxylase/pyruvate dehydrogenase activity (PC/PDH) in the synthesis of glutamate in nicergoline-treated aged rats is consistent with an increase in the transport of glutamine from glia to neurons for conversion into glutamate. In adult rat brains, no effect of nicergoline on glutamate PC/PDH activity was observed, although an increase in PC/PDH activity in glutamine was, suggesting that nicergoline affects the glutamate/glutamine cycle between neurons and glia in different ways depending on the age of animals. These results provide new insights into the effects of nicergoline on the CNS.

Effect of high-frequency repetitive transcranial magnetic stimulation on brain excitability in severely brain-injured patients in minimally conscious or vegetative state.

BACKGROUND: Repetitive transcranial magnetic stimulation (rTMS) induces prolonged functional changes in the cerebral cortex in normal conditions and in altered states of consciousness. Its therapeutic effects have been variously documented. OBJECTIVE: The aim of this study was to investigate the reactivity of electroencephalography (EEG) and the clinical response in six severely brain-injured patients in an altered state of consciousness (minimally conscious state [MCS] or vegetative state [VS]). EEG rhythm and brain excitability were measured before and after a protocol of high-frequency rTMS. METHODS: All six patients underwent clinical and neurophysiological evaluation before rTMS and immediately thereafter. EEG data in resting state were acquired at the beginning of the exam (T0), after rTMS (T1), and 38 min after rTMS (T2). From these data the power values were computed using Fast Fourier Transform. RESULTS: rTMS over the motor cortex induced long-lasting behavioral and neurophysiological modifications in only one patient in MCS. No significant clinical or EEG modifications were detected in any of the other patients, except for changes in motor threshold and motor evoked potential amplitude over the stimulated motor areas. CONCLUSIONS: The main finding of the study is the correlation between EEG reactivity and clinical response after rTMS. Reappearance of fast activity and an increase in slow activity were noted in the one patient with transitory arousal, whereas no significant reliable changes were observed in the other patients showing no clinical reactivity.

Behavioral and neurophysiological effects of repetitive transcranial magnetic stimulation on the minimally conscious state: a case study.

BACKGROUND: In 2007, Schiff et al reported a patient in a minimally conscious state (MCS) who responded to deep brain stimulation (DBS), but clinicians cannot predict which patients might respond prior to the implantation of electrodes. METHODS: A patient in a MCS for 5 years participated in an ABA design alternating between repetitive transcranial magnetic stimulation (rTMS) and peripheral nerve stimulation. rTMS (condition A) involved the delivery of 10 trains of 100 stimuli at 20 Hz using a stimulator with a 70-mm figure-of-eight coil to elicit a contraction of the abductor pollicis brevis. Condition B used median nerve electrical stimulation. RESULTS: After peripheral stimulation, the patient did not exhibit clinical, behavioral, or electroencephalographic (EEG) changes. The frequency of specific and meaningful behaviors increased after rTMS, along with the absolute and relative power of the EEG δ, ß, and α bands. CONCLUSION: These results suggest that rTMS may improve awareness and arousal in MCS. If these results are reproducible, rTMS may identify subgroups of MCS patients who might benefit from DBS.

Post-ischemic brain damage: NF-kappaB dimer heterogeneity as a molecular determinant of neuron vulnerability.

Nuclear factor-kappaB (NF-kappaB) has been proposed to serve a dual function as a regulator of neuron survival in pathological conditions associated with neurodegeneration. NF-kappaB is a transcription family of factors comprising five different proteins, namely p50, RelA/p65, c-Rel, RelB and p52, which can combine differently to form active dimers in response to external stimuli. Recent research shows that diverse NF-kappaB dimers lead to cell death or cell survival in neurons exposed to ischemic injury. While the p50/p65 dimer participates in the pathogenesis of post-ischemic injury by inducing pro-apoptotic gene expression, c-Rel-containing dimers increase neuron resistance to ischemia by inducing anti-apoptotic gene transcription. We present, in this report, the latest findings and consider the therapeutic potential of targeting different NF-kappaB dimers to limit ischemia-associated neurodegeneration.

NF-kappaB dimers in the regulation of neuronal survival.

Nuclear factor-kappaB (NF-kappaB) is a dimeric transcription factor composed of five members, p50, RelA/p65, c-Rel, RelB, and p52 that can diversely combine to form the active transcriptional dimer. NF-kappaB controls the expression of genes that regulate a broad range of biological processes in the central nervous system such as synaptic plasticity, neurogenesis, and differentiation. Although NF-kappaB is essential for neuron survival and its activation may protect neurons against oxidative-stresses or ischemia-induced neurodegeneration, NF-kappaB activation can contribute to inflammatory reactions and apoptotic cell death after brain injury and stroke. It was proposed that the death or survival of neurons might depend on the cell type and the timing of NF-kappaB activation. We here discuss recent evidence suggesting that within the same neuronal cell, activation of diverse NF-kappaB dimers drives opposite effects on neuronal survival. Unbalanced activation of NF-kappaB p50/RelA dimer over c-Rel-containing complexes contributes to cell death secondary to the ischemic insult. While p50/RelA acts as transcriptional inducer of Bcl-2 family proapoptotic Bim and Noxa genes, c-Rel dimers specifically promote transcription of antiapototic Bcl-xL gene. Changes in the nuclear content of c-Rel dimers strongly affect the threshold of neuron vulnerability to ischemic insult and agents, likewise leptin, activating a NF-kappaB/c-Rel-dependent transcription elicit neuroprotection in animal models of brain ischemia.