Effect of systemic kynurenine on cortical spreading depression and its modulation by sex hormones in rat.
Chauvel, Virginie ; ; et al
in Experimental Neurology (2012), 236(2), 207-14
BACKGROUND: The aura symptoms in migraine are most likely due to cortical spreading depression (CSD). CSD is favored by NMDA receptor activation and increased cortical excitability. The latter probably ... [more ▼]
BACKGROUND: The aura symptoms in migraine are most likely due to cortical spreading depression (CSD). CSD is favored by NMDA receptor activation and increased cortical excitability. The latter probably explains why migraine with aura may appear when estrogen levels are high, like during pregnancy. Kynurenic acid, a derivative of tryptophan metabolism, is an endogenous NMDA receptor antagonist whose cerebral concentrations can be augmented by systemic administration of its precursor l-kynurenine. OBJECTIVE: To determine if exogenous administration of l-kynurenine is able to influence KCl-induced CSD in rat, if the effect is sex-dependent and if it differs in females between the phases of the estrous cycle. METHODS: Adult Sprague-Dawley rats (n=8/group) received intraperitoneal (i.p.) injections of l-kynurenine (L-KYN, 300mg/kg), L-KYN combined with probenecid (L-KYN+PROB) that increases cortical concentration of KYNA by blocking its excretion from the central nervous system, probenecid alone (PROB, 200mg/kg) or NaCl. Cortical kynurenic acid concentrations were determined by HPLC (n=7). Thirty minutes after the injections, CSDs were elicited by application of 1M KCl over the occipital cortex and recorded by DC electrocorticogram. In NaCl and L-KYN groups, supplementary females were added and CSD frequency was analyzed respective to the phases of the estrous cycle determined by vaginal smears. RESULTS: In both sexes, PROB, L-KYN and L-KYN+PROB increased cortical kynurenic acid level. PROB, L-KYN and L-KYN+PROB with increasing potency decreased CSD frequency in female rats, while in males such an effect was significant only for L-KYN+PROB. The inhibitory effect of L-KYN on CSD frequency in females was most potent in diestrus. CONCLUSION: l-Kynurenine administration suppresses CSD, most likely by increasing kynurenic acid levels in the cortex. Females are more sensitive to this suppressive effect of l-kynurenine than males. These results emphasize the role of sex hormones in migraine and open interesting novel perspectives for its preventive treatment. [less ▲]Detailed reference viewed: 8 (1 ULg)
Mesenchymal Stem Cell Graft Improves Recovery after Spinal Cord Injury in Adult Rats through Neurotrophic and Pro-Angiogenic Actions.
; Cantinieaux, Dorothée ; et al
in PLoS ONE (2012), 7(6), 39500
Numerous strategies have been managed to improve functional recovery after spinal cord injury (SCI) but an optimal strategy doesn't exist yet. Actually, it is the complexity of the injured spinal cord ... [more ▼]
Numerous strategies have been managed to improve functional recovery after spinal cord injury (SCI) but an optimal strategy doesn't exist yet. Actually, it is the complexity of the injured spinal cord pathophysiology that begets the multifactorial approaches assessed to favour tissue protection, axonal regrowth and functional recovery. In this context, it appears that mesenchymal stem cells (MSCs) could take an interesting part. The aim of this study is to graft MSCs after a spinal cord compression injury in adult rat to assess their effect on functional recovery and to highlight their mechanisms of action. We found that in intravenously grafted animals, MSCs induce, as early as 1 week after the graft, an improvement of their open field and grid navigation scores compared to control animals. At the histological analysis of their dissected spinal cord, no MSCs were found within the host despite their BrdU labelling performed before the graft, whatever the delay observed: 7, 14 or 21 days. However, a cytokine array performed on spinal cord extracts 3 days after MSC graft reveals a significant increase of NGF expression in the injured tissue. Also, a significant tissue sparing effect of MSC graft was observed. Finally, we also show that MSCs promote vascularisation, as the density of blood vessels within the lesioned area was higher in grafted rats. In conclusion, we bring here some new evidences that MSCs most likely act throughout their secretions and not via their own integration/differentiation within the host tissue. [less ▲]Detailed reference viewed: 16 (7 ULg)
Sustained effeciveness of occipital nerve stimulation in drug-resistant chronic cluster headache
MAGIS, Delphine ; ; et al
in Headache (2011)Detailed reference viewed: 20 (11 ULg)
Involvement of placental growth factor in Wallerian degeneration
Chaballe, Linda ; Close, Pierre ; SEMPELS, Maxime et al
in Glia (2011), 59(3), 379-396
Wallerian degeneration (WD) is an inflammatory process of nerve degeneration, which occurs more rapidly in the peripheral nervous system compared with the central nervous system, resulting, respectively ... [more ▼]
Wallerian degeneration (WD) is an inflammatory process of nerve degeneration, which occurs more rapidly in the peripheral nervous system compared with the central nervous system, resulting, respectively in successful and aborted axon regeneration. In the peripheral nervous system, Schwann cells (SCs) and macrophages, under the control of a network of cytokines and chemokines, represent the main cell types involved in this process. Within this network, the role of placental growth factor (PlGF) remains totally unknown. However, properties like monocyte activation/attraction, ability to increase expression of pro-inflammatory molecules, as well as neuroprotective effects, make it a candidate likely implicated in this process. Also, nothing is described about the expression and localization of this molecule in the peripheral nervous system. To address these original questions, we decided to study PlGF expression under physiological and degenerative conditions and to explore its role in WD, using a model of sciatic nerve transection in wild-type and Pgf(-/-) mice. Our data show dynamic changes of PlGF expression, from periaxonal in normal nerve to SCs 24h postinjury, in parallel with a p65/NF-κB recruitment on Pgf promoter. After injury, SC proliferation is reduced by 30% in absence of PlGF. Macrophage invasion is significantly delayed in Pgf(-/-) mice compared with wild-type mice, which results in worse functional recovery. MCP-1 and proMMP-9 exhibit a 3-fold reduction of their relative expressions in Pgf(-/-) injured nerves, as demonstrated by cytokine array. In conclusion, this work originally describes PlGF as a novel member of the cytokine network of WD. [less ▲]Detailed reference viewed: 49 (19 ULg)
Central modulation in cluster headache patients treated with occipital nerve stimulation: an FDG-PET study
MAGIS, Delphine ; Bruno, Marie-Aurélie ; FUMAL, Arnaud et al
in BMC Neurology (2011), 11Detailed reference viewed: 28 (9 ULg)
Habituation of evoked responses is greater in patients with familial hemiplegic migraine than in controls: a contrast with the common forms of migraine.
; ; Magis, Delphine et al
in European Journal of Neurology (2011)
Background: Familial hemiplegic migraine (FHM) is a rare, dominantly inherited subtype of migraine with transient hemiplegia during the aura phase. Mutations in at least three different genes can produce ... [more ▼]
Background: Familial hemiplegic migraine (FHM) is a rare, dominantly inherited subtype of migraine with transient hemiplegia during the aura phase. Mutations in at least three different genes can produce the FHM phenotype. The mutated FHM genes code for ion transport proteins that animal and cellular studies have associated with disturbed ion homeostasis, altered cellular excitability, neurotransmitter release, and decreased threshold for cortical spreading depression. The common forms of migraine are characterized interictally by a habituation deficit of cortical and subcortical evoked responses that has been attributed to neuronal dysexcitability. FHM and the common forms of migraine are thought to belong to a spectrum of migraine phenotypes with similar pathophysiology, and we therefore examined whether an abnormal habituation pattern would also be found in FHM patients. Methods: In a group of genotyped FHM patients (five FHM-1, four FHM-2), we measured habituation of visual evoked potentials (VEP), auditory evoked potentials including intensity dependence (IDAP), the nociception-specific blink reflex (nsBR) and compared the results to a group of healthy volunteers (HV). Results: FHM patients had a more pronounced habituation during VEP (P = 0.025) and nsBR recordings (P = 0.023) than HV. There was no difference for IDAP, but the slope tended to be steeper in FHM. Conclusion: Contrary to the common forms of migraine, FHM patients are not characterized by a deficient, but rather by an increased habituation in cortical/brain stem evoked activities. These results suggest differences between FHM and the common forms of migraine, as far as central neuronal processing is concerned. [less ▲]Detailed reference viewed: 19 (5 ULg)
Post-mortem assessment of rat spinal cord injury and white matter sparing using inversion recovery-supported proton density magnetic resonance imaging
Scholtes, Félix ; ; Phan Ba, Remy et al
in Spinal Cord : The Official Journal of the International Medical Society of Paraplegia (2011)Detailed reference viewed: 21 (11 ULg)
Placental growth factor: a tissue modelling factor with therapeutic potentials in neurology?
Chaballe, Linda ; Schoenen, Jean ; Franzen, Rachelle
in Acta Neurologica Belgica (2011), 111(1), 10-7
Placental growth factor (PlGF) is an angiogenic factor that belongs to the vascular endothelial growth factor (VEGF) family. Besides its well known capacity to potentiate the angiogenic action of VEGF ... [more ▼]
Placental growth factor (PlGF) is an angiogenic factor that belongs to the vascular endothelial growth factor (VEGF) family. Besides its well known capacity to potentiate the angiogenic action of VEGF, PlGF also participates in inflammatory processes by attracting and activating monocytes; it plays therefore more specifically a role in pathological conditions. PIGF and its two receptors, VEGFR-1 and neuropilins (NRPs), are expressed in the brain and increase after experimental stroke, but their precise functions in the nervous system remain underexplored. In this review article, we summarize present knowledge on the role of PlGF in various nervous system disease processes. Given the available data, P1GF has neuroprotective and neurotrophic properties that make it an actor of considerable interest in the pathophysiology and potentially in the therapy of degenerative and traumatic brain or spinal cord diseases. [less ▲]Detailed reference viewed: 3 (0 ULg)
Neurophysiological tests and neuroimaging procedures in non-acute headache (2nd edition).
; ; et al
in European Journal of Neurology (2011), 18
Background and purpose: A large number of instrumental investigations are used in patients with non-acute headache in both research and clinical fields. Although the literature has shown that most of ... [more ▼]
Background and purpose: A large number of instrumental investigations are used in patients with non-acute headache in both research and clinical fields. Although the literature has shown that most of these tools contributed greatly to increasing understanding of the pathogenesis of primary headache, they are of little or no value in the clinical setting. Methods: This paper provides an update of the 2004 EFNS guidelines and recommendations for the use of neurophysiological tools and neuroimaging procedures in non-acute headache (first edition). Even though the period since the publication of the first edition has seen an increase in the number of published papers dealing with this topic, the updated guidelines contain only minimal changes in the levels of evidence and grades of recommendation. Results: (i) Interictal EEG is not routinely indicated in the diagnostic evaluation of patients with headache. Interictal EEG is, however, indicated if the clinical history suggests a possible diagnosis of epilepsy (differential diagnosis). Ictal EEG could be useful in certain patients suffering from hemiplegic or basilar migraine. (ii) Recording evoked potentials is not recommended for the diagnosis of headache disorders. (iii) There is no evidence warranting recommendation of reflex responses or autonomic tests for the routine clinical examination of patients with headache. (iv) Manual palpation of pericranial muscles, with standardized palpation pressure, can be recommended for subdividing patient groups but not for diagnosis. Pain threshold measurements and EMG are not recommended as clinical diagnostic tests. (v) In adult and pediatric patients with migraine, with no recent change in attack pattern, no history of seizures, and no other focal neurological symptoms or signs, the routine use of neuroimaging is not warranted. In patients with trigeminal autonomic cephalalgia, neuroimaging should be carefully considered and may necessitate additional scanning of intracranial/cervical vasculature and/or the sellar/orbital/(para)nasal region. In patients with atypical headache patterns, a history of seizures and/or focal neurological symptoms or signs, MRI may be indicated. (vi) If attacks can be fully accounted for by the standard headache classification (IHS), a PET or SPECT scan will normally be of no further diagnostic value. Nuclear medical examinations of the cerebral circulation and metabolism can be carried out in subgroups of patients with headache for the diagnosis and evaluation of complications, when patients experience unusually severe attacks or when the quality or severity of attacks has changed. (vii) Transcranial Doppler examination is not helpful in headache diagnosis. Conclusion: Although many of the examinations described in the present guidelines are of little or no value in the clinical setting, most of the tools, including thermal pain thresholds and transcranial magnetic stimulation, have considerable potential for differential diagnostic evaluation as well as for the further exploration of headache pathophysiology and the effects of pharmacological treatment. [less ▲]Detailed reference viewed: 8 (0 ULg)
Optimal management of migraine taking into account comorbidities and “positive side effects”
; ; Schoenen, Jean
in Schoenen, Jean; Dodick, DW; Sándor, C (Eds.) Comorbidity in Migraine (2011)Detailed reference viewed: 4 (0 ULg)
Treatment of migraine: update on new therapies.
MAGIS, Delphine ; Schoenen, Jean
in Current Opinion in Neurology (2011)
PURPOSE OF REVIEW: This review provides a comprehensive selection of the latest clinical trial results in antimigraine treatment. RECENT FINDINGS: The oral calcitonine gene-related peptide antagonist ... [more ▼]
PURPOSE OF REVIEW: This review provides a comprehensive selection of the latest clinical trial results in antimigraine treatment. RECENT FINDINGS: The oral calcitonine gene-related peptide antagonist telcagepant is efficacious in acute treatment. Compared to triptans, its efficacy is almost comparable but its tolerance is superior. The same is true for the 5HT-1F agonist lasmiditan, another agent devoid of vascular effects. Triptans, as other drugs, are more efficient if taken early but nonsteroidal anti-inflammatory drugs and analgesics remain useful for acute treatment, according to several meta-analyses. Single-pulse transcranial magnetic stimulation during the aura rendered more patients pain-free (39%) than sham stimulation (22%) in one study. Topiramate could be effective for migrainous vertigo, but it did not prevent transformation to chronic migraine in patients with high attack frequency. Onabotulinumtoxin A was effective for chronic migraine and well tolerated, but the therapeutic gain over placebo was modest; the clinical profile of responders remains to be determined before widespread use. Occipital nerve stimulation was effective in intractable chronic migraine with 39% of responders compared to 6% after sham stimulation. This and other neuromodulation techniques, such as sphenopalatine ganglion stimulation, are promising treatments for medically refractory patients but large controlled trials are necessary. One study suggests that outcome of patent foramen ovale closure in migraine might depend on anatomic and functional characteristics. SUMMARY: Drugs with a better efficacy or side-effect profile than triptans may soon become available for acute treatment. The future may also look brighter for some of the very disabled chronic migraineurs thanks to novel drug and neuromodulation therapies. [less ▲]Detailed reference viewed: 59 (12 ULg)
Effects of light deprivation on visual evoked potentials in migraine without aura.
; Cremers, Julien ; GERARD, Pascale et al
in BMC Neurology (2011), 11
BACKGROUND: The mechanisms underlying the interictal habituation deficit of cortical visual evoked potentials (VEP) in migraine are not well understood. Abnormal long-term functional plasticity of the ... [more ▼]
BACKGROUND: The mechanisms underlying the interictal habituation deficit of cortical visual evoked potentials (VEP) in migraine are not well understood. Abnormal long-term functional plasticity of the visual cortex may play a role and it can be assessed experimentally by light deprivation (LD). METHODS: We have compared the effects of LD on VEP in migraine patients without aura between attacks (MO, n = 17) and in healthy volunteers (HV, n = 17). Six sequential blocks of 100 averaged VEP at 3.1 Hz were recorded before and after 1 hour of LD. We measured VEP P100 amplitude of the 1st block of 100 sweeps and its change over 5 sequential blocks of 100 responses. RESULTS: In HV, the consequence of LD was a reduction of 1st block VEP amplitude and of the normal habituation pattern. By contrast, in MO patients, the interictal habituation deficit was not significantly modified, although 1st block VEP amplitude, already lower than in HV before LD, further decreased after LD. CONCLUSIONS: Light deprivation is thought to decrease both excitatory and subsequent inhibitory processes in visual cortex, which is in line with our findings in healthy volunteers. The VEP results in migraine patients suggest that early excitation was adequately suppressed, but not the inhibitory mechanisms occurring during long term stimulation and habituation. Accordingly, deficient intracortical inhibition is unlikely to be a primary factor in migraine pathophysiology and the habituation deficit. [less ▲]Detailed reference viewed: 12 (2 ULg)
Supraorbital transcutaneous neurostimulation has sedative effects in healthy subjects.
; ; SAVA, Simona Liliana et al
in BMC Neurology (2011), 11
BACKGROUND: Transcutaneous neurostimulation (TNS) at extracephalic sites is a well known treatment of pain. Thanks to recent technical progress, the Cefaly(R) device now also allows supraorbital TNS ... [more ▼]
BACKGROUND: Transcutaneous neurostimulation (TNS) at extracephalic sites is a well known treatment of pain. Thanks to recent technical progress, the Cefaly(R) device now also allows supraorbital TNS. During observational clinical studies, several patients reported decreased vigilance or even sleepiness during a session of supraorbital TNS. We decided therefore to explore in more detail the potential sedative effect of supraorbital TNS, using standardized psychophysical tests in healthy volunteers. METHODS: We performed a double-blind cross-over sham-controlled study on 30 healthy subjects. They underwent a series of 4 vigilance tests (Psychomotor Vigilance Task, Critical Flicker Fusion Frequency, Fatigue Visual Numeric Scale, d2 test). Each subject was tested under 4 different experimental conditions: without the neurostimulation device, with sham supraorbital TNS, with low frequency supraorbital TNS and with high frequency supraorbital TNS. RESULTS: As judged by the results of three tests (Psychomotor Vigilance Task, Critical Flicker Fusion Frequency, Fatigue Visual Numeric Scale) there was a statistically significant (p < 0.001) decrease in vigilance and attention during high frequency TNS, while there were no changes during the other experimental conditions. Similarly, performance on the d2 test was impaired during high frequency TNS, but this change was not statistically significant. CONCLUSION: Supraorbital high frequency TNS applied with the Cefaly(R) device decreases vigilance in healthy volunteers. Additional studies are needed to determine the duration of this effect, the underlying mechanisms and the possible relation with the stimulation parameters. Meanwhile, this effect opens interesting perspectives for the treatment of hyperarousal states and, possibly, insomnia. [less ▲]Detailed reference viewed: 9 (0 ULg)
Drug-induced changes in cortical inhibition in medication overuse headache.
; ; et al
in Cephalalgia : An International Journal of Headache (2011), 31(12), 1282-90
BACKGROUND: We investigated whether chronic headache related to medication overuse (MOH) is associated with changes in brain mechanisms regulating inhibitory cortical responses compared with healthy ... [more ▼]
BACKGROUND: We investigated whether chronic headache related to medication overuse (MOH) is associated with changes in brain mechanisms regulating inhibitory cortical responses compared with healthy volunteers and episodic migraineurs recorded between attacks, and whether these changes differ according to the drug overused. SUBJECTS AND METHODS: We studied 40 MOH patients whose symptoms were related to triptans alone, non-steroidal anti-inflammatory drugs (NSAIDs) or both medications combined, 12 migraineurs and 13 healthy volunteers. We used high-intensity transcranial magnetic stimulation over the primary motor cortex to assess the silent period from contracted perioral muscles. RESULTS: In MOH patients the cortical silent period differed according to the type of headache medication overused: in patients overusing triptans alone it was shorter than in healthy volunteers (44.7 +/- 14.2 vs. 108.1 +/- 30.1 ms), but similar to that reported in migraineurs (59.9 +/- 30.4 ms), whereas in patients overusing NSAIDs alone or triptans and NSAIDs combined duration of silent period was within normal limits (80.6 +/- 46.4 and 103.8 +/- 47.2 ms). CONCLUSIONS: Compared with episodic migraineurs, MOH patients overusing triptans have no significant change in cortical inhibition, whereas those overusing NSAIDs have an increase in cortical inhibitory mechanisms. We attribute these changes to medication-induced neural adaptation promoted by changes in central serotonin neurotransmission. [less ▲]Detailed reference viewed: 4 (0 ULg)
La neurostimulation : quelle place dans les céphalées réfractaires?
MAGIS, Delphine ; SCHOENEN, Jean
in Revue Médicale de Liège (2011), 66(2), 85-90Detailed reference viewed: 19 (1 ULg)
Peripheral nerve stimulation in chronic cluster headache.
MAGIS, Delphine ; Schoenen, Jean
in Progress in Neurological Surgery (2011), 24
Cluster headache is well known as one of the most painful primary neurovascular headache. Since 1% of chronic cluster headache patients become refractory to all existing pharmacological treatments ... [more ▼]
Cluster headache is well known as one of the most painful primary neurovascular headache. Since 1% of chronic cluster headache patients become refractory to all existing pharmacological treatments, various invasive and sometimes mutilating procedures have been tempted in the last decades. Recently, neurostimulation methods have raised new hope for drug-resistant chronic cluster headache patients. The main focus of this chapter is on stimulation of the great occipital nerve, which has been the best evaluated peripheral nerve stimulation technique in drug-resistant chronic cluster headache, providing the most convincing results so far. Other peripheral nerve stimulation approaches used for this indication are also reviewed in detail. Although available studies are limited to a relatively small number of patients and placebo-controlled trials are lacking, existent clinical data suggest that occipital nerve stimulation should nonetheless be recommended for intractable chronic cluster headache patients before more invasive deep brain stimulation surgery. More studies are needed to evaluate the usefulness of supraorbital nerve stimulation and of vagus nerve stimulation in management of cluster headaches. [less ▲]Detailed reference viewed: 5 (1 ULg)