Primary headache and multiple sclerosis: preliminary results of a prospective study

The aim of this study was to explore the association between different types of headache (HA) and the clinical features of multiple sclerosis (MS). The relationship between HA and MS-specific therapies was also analysed. A total of 102 MS patients were recruited at the MS Centre of S. Andrea Hospital in Rome. According to International Headache Society criteria, the lifetime prevalence of primary HA was 61.8%. Migraine was observed more often in young relapsing-remitting MS patients, whilst tension-type HA was associated with older age, male gender and a secondary progressive course. Sixty-four patients had a history of ongoing or past interferon beta (IFNb) exposure. Of these, 17 subjects did not have a history of HA, while 24 complained of an increase in frequency of migraine attacks and 7 reported an IFNb-induced HA. Investigating and treating HA in MS patients starting IFNb therapy may improve MS-specific medication compliance.

     

Creatine affects in vitro electrophysiological maturation of neuroblasts and protects them from oxidative stress

Creatine (Cr) is a very popular ergogenic molecule that has recently been shown to have antioxidant properties. The effectiveness of Cr supplementation in treating neurological diseases and Cr deficiency syndromes has been demonstrated, and experimental reports suggest that it plays an important role in CNS development. In spite of this body of evidence, the role of Cr in functional and structural neuronal differentiation is still poorly understood. Here we used electrophysiological, morphological, and biochemical approaches to study the effects of Cr supplementation on in vitro differentiation of spinal neuroblasts under standard conditions or subjected to oxidative stress, a status closely related to perinatal hypoxia-ischemia, a severe condition for developing brain. Cr supplementation (10 and 20 mM) completely prevented the viability decrease and neurite development impairment induced by radical attack, as well as nonprotein sulphydryl antioxidant pool depletion. Similar results were obtained using the antioxidant trolox. Furthermore, Cr supplementation induced a significant and dose-dependent anticipation of Na(+) and K(+) current expression during the period of in vitro network building. Consistently with the latter finding, higher excitability, expressed as number of spikes following depolarization, was found in supplemented neuroblasts. All effects were dependent on the cytosolic fraction of Cr, as shown using a membrane Cr-transporter blocker. Our results indicate that Cr protects differentiating neuroblasts against oxidative insults and, moreover, affects their in vitro electrophysiological maturation, suggesting possibly relevant effects of dietary Cr supplementation on developing CNS.     

Zonisamide for migraine prophylaxis in topiramate-intolerant patients: an observational study

(Headache 2011;51:287‐291) Background.— Zonisamide, a sulfonamide analog, is an antiepileptic drug with mechanisms of action similar to topiramate. Because of its pharmacodynamic and pharmacokinetics profiles, zonisamide is also potentially suitable for migraine prevention. Methods.— Tolerability and effectiveness of zonisamide for migraine prophylaxis in patients with a good response to topiramate, but interrupting it for intolerable side effects, were evaluated in 34 patients. After a 1‐month period of wash‐out, patients were treated with zonisamide (up to a 100 mg/day dosage) for 6 consecutive months. Results.— Zonisamide was well tolerated, only 4 (12%) patients reported transient and tolerable side effects. Mean number of days with headache per month was reduced from 14.9 ± 5.3 during the wash‐out period to 2.5 ± 0.6 after 6 months of zonisamide (P < .001). We observed a significant reduction in headache severity and disability, as assessed by visual analog scale and migraine disability assessment scale. Finally, when compared with the 1‐month period prior to starting zonisamide, a reduced use of analgesics was recorded at the end of the follow‐up. Conclusion.— Our findings support the use of zonisamide as an alternative therapy for migraine prevention in patients with good response, but poor tolerance to topiramate.     

Morpho-functional characterization of neuronal cells at different stages of maturation in granule cell layer of adult rat dentate gyrus

Neurogenesis occurs throughout adult life in dentate gyrus of mammal hippocampus. Therefore, neurons at different stages of electrophysiological and morphological maturation and showing various, if any, synaptic inputs co-exist in the adult granule cell layer, as occurs during dentate gyrus development. The knowledge of functional properties of new neurons throughout their maturation can contribute to understanding their role in the hippocampal function. In this study electrophysiological and morphological features of granule layer cells, characterized as immature or mature neurons, without and with synaptic input, were comparatively described in adult rats. The patch-clamp technique was used to perform electrophysiological recordings, the occurrence of synaptic input evoked by medial perforant pathway stimulation was investigated and synaptic input was characterized. Cells were then identified and morphologically described via detection of biocytin injected through the patch pipette. The neuronal phenotype of recorded cells was assessed by immunohistochemistry and single-cell RT-PCR. Cells with very low capacitance, high input resistance, depolarized resting membrane potential and without synaptic activity were found exclusively at the border of the GCL facing hilus; this type of cell expressed the class III beta-tubulin neuronal marker (mRNA and protein) and did not express a glial marker. Immature neuronal cells with progressively increasing capacitance, decreasing input resistance and resting membrane potential getting more hyperpolarized showed only depolarizing GABAergic synaptic input at first and then also glutamatergic synaptic input. Finally, cells showing electrophysiological, synaptic, and morphological features of mature granule, expressing the mature neuron marker NeuN, were identified.     

Efficacy and tolerability of pregabalin as preventive treatment for migraine: a 3-month follow-up study

Migraine is a common neurological disorder and epidemiological studies have documented its high social and economic impact. Unfortunately, preventive treatment is often insufficient to substantially reduce migraine frequency or it is not well tolerated. Antiepileptic drugs are increasingly used in migraine prevention. However, data on efficacy and tolerability of pregabalin in patients with migraine are still lacking. Our aim was to evaluate efficacy and tolerability of pregabalin in patients with migraine. We recruited 47 patients who started pregabalin at 75 mg/day, which was titrated to 300 mg/day as tolerated. A total of six patients (13%) reported one or more side effects during the intake of pregabalin; however, three of them discontinued pregabalin, because side effects were intolerable and persistent. Statistically significant reduction in migraine frequency compared to baseline (p < 0.001) was evident after 1 and 3 months of treatment. A greater frequency reduction was observed in those patients who increased the dosage within the first month of therapy. Our data suggest that pregabalin may be well tolerated and may represent an alternative preventive treatment in migraneurs. Limitations of the present study were a small sample size and an uncontrolled, open-label design; further randomized case–control studies are warranted to confirm our findings.     

Maternal dietary loads of α-tocopherol differentially influence fear conditioning and spatial learning in adult offspring

α-Tocopherol, the main component of vitamin E, is well known to be a radical scavenger, so an increased intake of vitamin E is recommended in complicated pregnancy, to prevent possible fetus damage by free radical. In a previous work, we found that maternal α-tocopherol supplementation affects PKC-mediated cellular signaling and hippocampal synaptic plasticity in developing brain; the latter effect persists in adulthood. Here, adult rats maternally exposed to supranutritional doses of α-tocopherol were evaluated for Contextual Fear Conditioning and spatial learning in Morris Water Maze, two different hippocampus-dependent learning tasks. Moreover, anxiety, spontaneous activity, and explorative drive were also evaluated as factors potentially affecting learning performance. Treated rats showed a different behavior with respect to controls: performance in Contextual Fear Conditioning was improved, while spatial learning tested in Morris Water Maze, was impaired. The improvement of fear response was not ascribable to differences in anxiety level and/or spontaneous activity; thus it appears to be a specific effect of α-tocopherol overloading during brain development. On the contrary, the impaired performance in Morris Water Maze exhibited by treated rats can be in part explained by their enhanced explorative drive. Although extrapolation from rats to humans is difficult, a caveat in assuming supranutritional doses of vitamin E in pregnancy arises from this study.     

Motor activity affects adult skeletal muscle re‐innervation acting via tyrosine kinase receptors

Recently, muscle expression of brain‐derived neurotrophic factor (BDNF) mRNA and protein under activity control has been reported. BDNF is a neurotrophin known to be involved in axon sprouting in the CNS. Hence, we set out to study the effect of chronic treadmill mid‐intensity running on adult rat muscle re‐innervation, and to explore the involvement of BDNF and tropomyosin‐related kinase (Trk) receptors. After nerve crush, muscle re‐innervation was evaluated using intracellular recordings, tension recordings, immunostaining and Western blot analyses. An enhanced muscle multiple innervation was found in running rats that was fully reversed to control values blocking Trk receptors or interrupting the running activity. An increase in muscle multiple innervation was also found in sedentary rats treated with a selective TrkB receptor agonist. The expression of TrkB receptors by intramuscular axons was demonstrated, and increased muscle expression of BDNF was found in running animals. The increase in muscle multiple innervation was consistent with the faster muscle re‐innervation that we found in running animals. We conclude that, when regenerating axons contact muscle cells, muscle activity progressively increases modulating BDNF and possibly other growth factors, which in turn, acting via Trk receptors, induce axon sprouting to re‐innervate skeletal muscle.     

Synaptogenesis in adult‐generated hippocampal granule cells is affected by behavioral experiences

Adult‐generated hippocampal immature neurons play a functional role after integration in functional circuits. Previously, we found that hippocampus‐dependent learning in Morris water maze affects survival of immature neurons, even before they are synaptically contacted. Beside learning, this task heavily engages animals in physical activity in form of swimming; physical activity enhances hippocampal neurogenesis. In this article, the effects of training in Morris water maze apparatus on the synapse formation onto new neurons in hippocampus dentate gyrus and on neuronal maturation were investigated in adult rats. Newborn cells were identified using retroviral GFP‐expressing virus infusion. In the first week after virus infusion, rats were trained in Morris water maze apparatus in three different conditions (spatial learning, cue test, and swimming). Properties of immature neurons and their synaptic response to perforant pathway stimulation were electrophysiologically investigated early during neuronal maturation. In controls, newborn cells showing GABAergic and glutamatergic responses were found for the first time at 8 and 10 days after mitosis, respectively; no cell with glutamatergic response only was found. Twelve days after virus infusion almost all GFP‐positive cells showed both synaptic responses. The main result we found was the anticipated appearance of GABAergic synapses at 6 days in learner, cued and swimmer rats, supported also by immunohistochemical result. Swimmer rats showed the highest percentage of GFP‐positive neurons with glutamatergic response at 10 and 12 days postmitosis. Moreover, primary dendrites were more numerous at 7 days in learner, cued and swimmer rats and swimmer rats showed the greatest dendritic tree complexity at 10 days. Finally, voltage‐dependent Ca²⁺ current was found in a larger number of newborn neurons at 7 days postinfusion in learner, cued and swimmer rats. In conclusion, experiences involving physical activity contextualized in an exploring behavior affect synaptogenesis in adult‐generated cells and their early stages of maturation. © 2009 Wiley‐Liss, Inc.     

The use of ID migraine™ questionnaire in patients with multiple sclerosis

Primary headaches are underdiagnosed and undertreated in patients with multiple sclerosis (MS). The aim of our study was to investigate the possibility of using the ID migraine™ (ID-M) questionnaire to make a first-line diagnosis of migraine in subjects affected by MS. We consecutively recruited 144 patients regularly attending the MS Centre of S. Andrea Hospital in Rome. Results from ID-M were matched with diagnoses of a blind neurologist. According to the ICHD-II criteria, 77 (53.5%) patients were diagnosed as suffering from migraine. ID-M showed high sensitivity (91%) and specificity (94%) in identifying patients with migraine. ID-M was also able to discriminate patients affected by headache following interferon beta therapy, having only the 10% out of these patients a positive ID-M. The use of the ID-M as a screening test is warranted not only in the epidemiological research, but also to ensure a better clinical management of patients with MS.     

Age-related naturally occurring depression of hippocampal neurogenesis does not affect trace fear conditioning

New neuron production throughout adulthood in granule cell layer (GCL) of rat hippocampus is a well-known phenomenon. A role of new neurons in hippocampal learning has been proposed, but the question is still open. A reduction of neural precursor proliferation in GCL of 2-month-old rats to about 20%, induced by the cytostatic agent methylazoxymethanol, was found to cause impairment in trace conditioning, suggesting a role of immature neurons in this kind of hippocampus-dependent learning (Shors et al., Hippocampus 2002;12:578-584). Neurogenesis decreases with increasing age. In this study, neural precursor proliferation and newborn cell survival were evaluated in GCL of adult rats within a range of ages following development and preceding old age. In 5-month-old rats, neural precursor proliferation was reduced to 57% and newborn cell survival was reduced to 40% in comparison to rats of 2 months of age; in 12-month-old rats, the decrease was to 5 and 4%, respectively. Consistently, the density of immature neurons decreased to 41 and 13% in 5- and 12-month-old rats, respectively. The role of neurogenesis in trace fear conditioning was studied in this natural model of neurogenesis depression. No impairment in trace fear conditioning was found both in 5- and 12-month-old rats in comparison to 2-month-old rats, notwithstanding the decrease of neurogenesis that is marked in 12-month-old rats. This finding shows that a lower rate of neurogenesis is sufficient for learning in 12-month-old rats in comparison to young rats.