Safety findings from CENTURION, a phase 3 consistency study of lasmiditan for the acute treatment of migraine

BACKGROUND

Lasmiditan (LTN) is a selective 5-HT_1F receptor agonist for the acute treatment of migraine in adults. We present detailed safety findings from the placebo-controlled, double-blind Phase 3 study, of LTN treatment across 4 attacks (CENTURION).

METHODS

Patients were randomized 1:1:1 to LTN 200 mg (LTN200), LTN100, or a control group that received placebo for 3 attacks and LTN50 for either the 3rd or 4th attack (1:1). Safety analyses were conducted for patients who took ≥1 dose of study drug and, in some cases, those who took all 4 doses.

RESULTS

Overall, 1471 patients treated 4494 attacks. The incidences of treatment-emergent serious adverse events (SAEs) were - placebo, n=2 (0.4 %); LTN100, n=1 (0.2 %); LTN200, n=2 (0.4 %); no specific treatment-emergent SAE was reported in more than one patient. The most common treatment emergent adverse events (TEAEs) with lasmiditan were dizziness, paresthesia, fatigue, nausea, vertigo, and somnolence; the vast majority were mild or moderate in severity. The incidences of these TEAEs were highest during the first attack and decreased during subsequent attacks. For patients who experienced a common TEAE with the first attack, less than 45 % experienced the same event in subsequent attacks. Patients who did not experience an event in the 1st attack infrequently experienced the same event in subsequent attacks. The time of onset of the common TEAE ranged from ~40 min to 1 h (dependent upon TEAE) and, for individual TEAE, the onset was similar across attacks. Duration was dependent upon TEAE and attack. It was shortest for paresthesia (< 2 h for all attacks); it ranged from 1.8 to 5.5 h for other common TEAEs and was generally similar across attacks. Serotonin syndrome was reported for 2 patients post LTN dosing; there were no meaningful differences across treatment groups in suicidality; there was no evidence of an increase in motor vehicle accidents.

CONCLUSION

In this blinded, controlled, multiple-attack study, LTN was associated with generally mild or moderate CNS-related TEAEs of short duration. TEAEs tended to decrease in frequency across the 4 attacks.

TRIAL REGISTRATION

NCT03670810.

Anodal transcranial direct current stimulation in chronic migraine and medication overuse headache: A pilot double-blind randomized sham-controlled trial

OBJECTIVES

Little evidence is available on the role of transcranial direct current stimulation (tDCS) in patients affected by chronic migraine (CM) and medication overuse headache (MOH). We aim to investigate the effects of tDCS in patients with CM and MOH as well as its role on brain activity.

METHODS

Twenty patients with CM and MOH were hospitalized for a 7-day detoxification treatment. Upon admission, patients were randomly assigned to anodal tDCS or sham stimulation delivered over the primary motor cortex contralateral to the prevalent migraine pain side every day for 5 days. Clinical data were recorded at baseline (T0), after 1 month (T2) and 6 months (T3). EEG recording was performed at T0, at the end of the tDCS/Sham treatment, and at T2.

RESULTS

At T2 and T3, we found a significant reduction in monthly migraine days (p = 0.001), which were more pronounced in the tDCS group when compared to the sham group (p = 0.016). At T2, we found a significant increase of alpha rhythm in occipital leads, which was significantly higher in tDCS group when compared to sham group.

CONCLUSIONS

tDCS showed adjuvant effects to detoxification in the management of patients with CM and MOH. The EEG recording showed a significant potentiation of alpha rhythm, which may represent a correlate of the underlying changes in cortico-thalamic connections.

SIGNIFICANCE

This study suggests a possible role for tDCS in the treatment of CM and MOH. The observed clinical improvement is coupled with a potentiation of EEG alpha rhythm.

Poor patient awareness and frequent misdiagnosis of migraine: findings from a large transcontinental cohort

BACKGROUND AND PURPOSE

Although migraine is the second most disabling condition worldwide, there is poor awareness of it. The objective was to assess the awareness of migraine and previous diagnostic and therapeutic consultations and treatments in a large international population of migraineurs.

METHODS

This was a multicentre study conducted in 12 headache centres in seven countries. Each centre recruited up to 100 patients referred for a first visit and diagnosed with migraine. Subjects were given a structured clinical questionnaire-based interview about the perceptions of the type of headache they suffered from, its cause, previous diagnoses, investigations and treatments.

RESULTS

In all, 1161 patients completed the study. Twenty-eight per cent of participants were aware that they suffered from migraine. Sixty-four per cent called their migraine 'headache'; less commonly they used terms such as 'cervical pain' (4%), tension headache (3%) and sinusitis (1%). Eight per cent of general practitioners and 35% of specialists (of whom 51% were neurologists and/or headache specialists) consulted for migraine formulated the correct diagnosis. Before participating in the study, 50% of patients had undergone X-ray, computed tomography and/or magnetic resonance imaging of the cervical spine and 76% underwent brain and/or cervical spine imaging for migraine. Twenty-eight per cent of patients had received symptomatic migraine-specific medications and 29% at least one migraine preventive medication.

CONCLUSIONS

Although migraine is a very common disease, poor awareness of it amongst patients and physicians is still an issue in several countries. This highlights the importance of the promotion of migraine awareness to reduce its burden and limit direct and indirect costs and the risk of exposure to useless investigations.

Current Prophylactic Medications for Migraine and Their Potential Mechanisms of Action

A relatively high number of different medications is currently used for migraine prevention in clinical practice. Although these compounds were initially developed for other indications and differ in their mechanisms of action, some general themes can be identified from the mechanisms at play. Efficacious preventive drugs seem to either suppress excitatory nervous signaling via sodium and/or calcium receptors, facilitate GABAergic inhibition, reduce neuronal sensitization, block cortical spreading depression and/or reduce circulating levels of CGRP. We here review such mechanisms for the different compounds.

The headache under-response to treatment (HURT) questionnaire, an outcome measure to guide follow-up in primary care: development, psychometric evaluation and assessment of utility

Background

Headache disorders are both common and burdensome but, given the many people affected, provision of health care to all is challenging. Structured headache services based in primary care are the most efficient, equitable and cost-effective solution but place responsibility for managing most patients on health-care providers with limited training in headache care. The development of practical management aids for primary care is therefore a purpose of the Global Campaign against Headache. This manuscript presents an outcome measure, the Headache Under-Response to Treatment (HURT) questionnaire, describing its purpose, development, psychometric evaluation and assessment for clinical utility. The objective was a simple-to-use instrument that would both assess outcome and provide guidance to improving outcome, having utility across the range of headache disorders, across clinical settings and across countries and cultures.

Methods

After literature review, an expert consensus group drawn from all six world regions formulated HURT through item development and item reduction using item-response theory. Using the American Migraine Prevalence and Prevention Study’s general-population respondent panel, two mailed surveys assessed the psychometric properties of HURT, comparing it with other instruments as external validators. Reliability was assessed in patients in two culturally-contrasting clinical settings: headache specialist centres in Europe (n = 159) and primary-care centres in Saudi Arabia (n = 40). Clinical utility was assessed in similar settings (Europe n = 201; Saudi Arabia n = 342).

Results

The final instrument, an 8-item self-administered questionnaire, addressed headache frequency, disability, medication use and effect, patients’ perceptions of headache “control” and their understanding of their diagnoses. Psychometric evaluation revealed a two-factor model (headache frequency, disability and medication use; and medication efficacy and headache control), with scale properties apparently stable across disorders and correlating well and in the expected directions with external validators. The literature review found few instruments linking assessment to clinical advice or suggested actions: HURT appeared to fill this gap. In European specialist care, it showed utility as an outcome measure across headache disorders. In Saudi Arabian primary care, HURT (translated into Arabic) was reliable and responsive to clinical change.

Conclusions

With demonstrated validity and clinical utility across disorders, cultures and settings, HURT is available for clinical and research purposes.

Electronic supplementary material

The online version of this article (10.1186/s10194-018-0842-6) contains supplementary material, which is available to authorized users.

Variability of the characteristics of a migraine attack within patients

Background

Migraine attacks may present different features in different patients and also within the same patient. The percentage of patients reporting stereotyped attacks and those reporting attacks with different phenotypes has not been the object of specific investigations.

Objective

The objective of this article is to evaluate the percentage of migraine patients reporting the same characteristics, in terms of phenotype and response to symptomatic medications on three consecutive migraine attacks.

Methods

Thirty patients with migraine without aura prospectively recorded the features of three consecutive attacks in a headache diary. Characteristics recorded were: pain intensity, presence of nausea, vomiting, photophobia, phonophophia, osmophobia, allodynia, cranial autonomic symptoms (at least one), and premonitory symptoms. Patients were allowed to take frovatriptan as symptomatic medication, whose efficacy was evaluated as the two hours pain-free status.

Results

None of the patients presented identical characteristics on the three studied attacks. This was still the case if we reduced the number of variables evaluated from 11 to seven of the eight core features indicated by the ICHD. Considering just six variables: unilaterality and quality of pain, presence/absence of nausea, vomiting, photophobia and phonophobia, only two patients (6%) had identical features on three consecutive attacks. With respect to the response to frovatriptan, 39% of patients had the same response, either positive (i.e. pain free after two hours) or negative (i.e. not pain free after two hours) on three consecutive attacks.

Conclusion

Migraine attacks show a high variability not just among patients, but also within the same patient. Our data indicate that stereotypy of attacks is uncommon, and reinforces the underlying logic of the current operational classification system.

Psychological factors associated with failure of detoxification treatment in chronic headache associated with medication overuse

Aim

The aim of this study was to evaluate the psychological factors associated with a negative outcome following detoxification in a 2-month follow-up in medication-overuse headache.

Methods

All consecutive patients entering the detoxification program were analysed in a prospective, non-randomised fashion. Psychiatric conditions and personality characteristics were assessed using the Structured Clinical Interview for DSM-IV Disorders (SCID-I) and the Minnesota Multiphasic Personality Inventory (MMPI)-2. χ2 tests, one-way analyses of variance, and odds ratios (ORs) were used.

Results

A total of 248 patients completed the follow-up: 156 stopped overuse and their headaches reverted to an episodic pattern (Group A); 23 kept overusing without any benefit on headache frequency (Group B); and 51 stopped overuse without any benefit on headache frequency (Group C). The prognostic factors for the outcome of Group B were higher scores on the correction (OR 1.128; p = 0.036), depression (OR 1.071; p = 0.05), hysteria (OR 1.106; p = 0.023), and overcontrolled hostility (OR 1.182; p = 0.04) MMPI-2 scales, whereas those for Group C were psychiatric comorbidities (OR 1.502; p = 0.021) and higher scores on the hysteria scale (OR 1.125; p = 0.004).

Conclusions

The outcome of detoxification is influenced by psychological factors that should be considered when considering treatment strategies.

Parthenolide is the Component of Tanacetum Parthenium that Inhibits Nitroglycerin-Induced Fos Activation: Studies in an Animal Model of Migraine

Tanacetum parthenium (TP) is a member of the Asteracee family long used empirically as a herbal remedy for migraine. So far, however, clinical trials have failed to prove consistently the effectiveness of TP extracts in preventing migraine attacks, probably as a consequence of the uncertainty as regards the active principle. In this study, the biological effects of different TP extracts and purified parthenolide were tested in an animal model of migraine based on the quantification of neuronal activation induced by nitroglycerin. The extract enriched in parthenolide significantly reduced nitroglycerin-induced Fos expression in the nucleus trigeminalis caudalis. Purified parthenolide inhibited nitroglycerin-induced neuronal activation in additional brain nuclei and, significantly, the activity of nuclear factor-κB. These findings strongly suggest that parthenolide is the component responsible for the biological activity of TP as regards its antimigraine effect and provide important information for future controlled clinical trials.

Peripheral Levels of BDNF and NGF in Primary Headaches

Neurotrophins, such as brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF), have been implicated in the generation and modulation of pain. To investigate whether alterations in neurotrophin levels can be detected in subjects suffering from nociceptive disorders, such as primary headaches, we determined the peripheral (platelet and plasma) levels of BDNF and NGF in patients suffering from migraine, with or without aura, or cluster headache (CH), in the interictal phase, and in healthy volunteers. All primary headaches patients studied showed significantly decreased platelet levels of BDNF (migraine vs. controls P < 0.001; CH vs. controls P < 0.01), while a selective reduction of platelet NGF was observed in migraine sufferers and not in CH patients compared with control subjects (migraine vs. controls P < 0.001). These changes were not accompanied by significant modifications of neurotrophin plasma levels. Our findings show for the first time that changes in peripheral levels of neurotrophines (BDNF and NGF) occur in patients suffering from different types of primary headaches, suggesting a potential involvement of BDNF and NGF in the pathophysiology of these disorders, and raising the possibility that differences in peripheral neurotrophins may help to distinguish migraine biologically from CH.

Impact of headache disorders in Italy and the public-health and policy implications: a population-based study within the Eurolight Project

Background

Migraine, tension-type headache (TTH) and medication-overuse headache (MOH) are disabling lifelong illnesses. The Eurolight project, a partnership activity within the Global Campaign against Headache, assessed the impact of headache disorders in ten countries in Europe using a structured questionnaire coupled with various sampling methods. Here we present the findings from the Italian population.

Methods

Questionnaires were distributed to a stratified sample (N = 3500) of the adult (18–65 years) inhabitants of Pavia province (1.05 % of the general population), randomly selected in cooperation with the local health service. Questions included demographic and diagnostic enquries, and assessment of various aspects of impact and health-care utilisation.

Results

Altogether 500 questionnaires were returned of which 487 were adequately completed for analysis (58 % female, 42 % male). Among these, gender-adjusted lifetime prevalence of headache was 82.5 %, higher in females than in males (91.2 % vs 72.4 %; p < 0.0001). Gender-adjusted 1-year prevalence was 74.2 % (females 87.7 %, males 61.1 %; p < 0.0001). The most prevalent headache type was migraine (gender-adjusted 1-year prevalence 42.9 %; females 54.6 %, males 32.5 %; p < 0.0001), followed by TTH (28.6 %; no gender-related difference); all causes of headache on ≥15 days/month were reported by 7.0 % of participants (females 10.6 %, males 2.0 %; p = 0.0002), of whom 2.1 %,, all female (p = 0.0064) concomitantly overused acute medications (therefore probable MOH). Only 16.6 % of responders reporting headache had received a diagnosis from a doctor, and very few (2.4 %) were taking preventative medications. Headache had negative impacts on different aspects of life: education, career and earnings, family and social life. Each person with headache had lost, on average, 2.3 days from paid work and 2.4 days from household work, and missed social occasions on 1.2 days, in the preceding 3 months. An increasing gradient for impact was observed from episodic to chronic forms of headache.

Conclusions

Our study reveals that in Italy, as in other countries, migraine, TTH and MOH are highly prevalent and are associated with significant personal impact. These findings have important implications for health policy in Italy.

Cost of Chronic and Episodic Migraine. A pilot study from a tertiary headache centre in northern Italy

BACKGROUND

Chronic migraine (CM) has a high impact on functional performance and quality of life (QoL). CM also has a relevant burden on the National Health Service (NHS), however precise figures are lacking. In this pilot study we compared the impact in terms of costs of CM and episodic migraine (EM) on the individual and on the National Health System (NHS). Furthermore, we comparatively evaluated the impact of CM and EM on functional capability and on QoL of sufferers.

METHODS

We enrolled 92 consecutive patients attending the Pavia headache centre: 51 subjects with CM and 41 with episodic migraine (EM). Patients were tested with disability scales (MIDAS, HIT-6, SF-36) and with an ad hoc semi-structured questionnaire.

RESULTS

The direct mean annual cost (in euro) per patient suffering from CM was €2250.0 ± 1796.1, against €523.6 ± 825.8 per patient with EM. The cost loaded on NHS was €2110.4 ± 1756.9 for CM, €468.3 ± 801.8 for EM. The total economic load and the different sub-items were significantly different between groups (CM vs. EM p = 0.001 for each value). CM subjects had higher scores than EM for MIDAS (98.4 ± 72,3 vs 15.5 ± 17.7, p = 0.001) and for HIT-6 (66.1 ± 8.4 vs 58.7 ± 10.1, p = 0.001). The SF-36 score was 39.9 ± 14,74 for CM and 66.2 ± 18.2 for EM (p = 0.001).

CONCLUSIONS

CM is a disabling condition with a huge impact on the QoL of sufferers and a significant economic impact on the NHS. The adequate management of CM, reverting it back to EM, will provide a dual benefit: on the individual and on the society.

Effects of peripheral FAAH blockade on NTG-induced hyperalgesia--evaluation of URB937 in an animal model of migraine

BACKGROUND

Systemic nitroglycerin (NTG) activates brain nuclei involved in nociceptive transmission as well as in neuroendocrine and autonomic functions in rats. These changes are considered relevant for migraine because NTG consistently provokes spontaneous-like migraine attacks in migraineurs. Several studies have suggested a relationship between the endocannabinoid levels and pain mediation in migraine. URB937, a peripheral inhibitor of fatty acid amide hydrolase (FAAH)-the enzyme that degrades anandamide, produces analgesia in animal models of pain, but there is no information on its effects in migraine.

AIM

We evaluated whether URB937 alters nociceptive responses in the animal model of migraine based on NTG administration in male rats, using the tail flick test and the plantar and orofacial formalin tests, under baseline conditions and after NTG administration. Furthermore, we investigated whether URB937 affects NTG-induced c-Fos expression in the brain.

RESULTS

During the tail flick test, URB937 showed an antinociceptive effect in baseline conditions and it blocked NTG-induced hyperalgesia. URB937 also proved effective in counteracting NTG-induced hyperalgesia during both the plantar and orofacial formalin tests. Mapping of brain nuclei activated by NTG indicates that URB937 significantly reduces c-Fos expression in the nucleus trigeminalis caudalis and the locus coeruleus.

CONCLUSIONS

The data suggest that URB937 is capable of changing, probably via indirect mechanisms, the functional status of central structures that are important for pain transmission in an animal model of migraine.

Early reperfusion injury is associated to MMP2 and IL-1β elevation in cortical neurons of rats subjected to middle cerebral artery occlusion

The pathophysiological processes implicated in ischemic brain damage are strongly affected by an inflammatory reaction characterized by activation of immune cells and release of soluble mediators, including cytokines and chemokines. The pro-inflammatory cytokine interleukin (IL)-1β has been implicated in ischemic brain injury, however, to date, the mechanisms involved in the maturation of this cytokine in the ischemic brain have not been completely elucidated. We have previously suggested that matrix metalloproteinases (MMPs) may be implicated in cytokine production under pathological conditions. Here, we demonstrate that significant elevation of IL-1β occurs in the cortex as early as 1h after the beginning of reperfusion in rats subjected to 2-h middle cerebral artery occlusion (MCAo). At this early stage, we observe increased expression of IL-1β in pericallosal astroglial cells and in cortical neurons and this latter signal colocalizes with elevated gelatinolytic activity. By gel zymography, we demonstrate that the increased gelatinolytic signal at 1-h reperfusion is mainly ascribed to MMP2. Thus, MMP2 seems to contribute to early brain elevation of IL-β after transient ischemia and this mechanism may promote damage since pharmacological inhibition of gelatinases by the selective MMP2/MMP9 inhibitor V provides neuroprotection in rats subjected to transient MCAo.

Functional polymorphisms in COMT and SLC6A4 genes influence the prognosis of patients with medication overuse headache after withdrawal therapy

BACKGROUND AND PURPOSE

It is currently unknown if common genetic variants influence the prognosis of patients with medication overuse headache (MOH). Here the role of two common single nucleotide polymorphisms in the COMT gene (rs4680 and rs6269), as well as the STin2 variable number tandem repeat (VNTR) polymorphism in the SLC6A4 gene, were evaluated as predictors for long-term outcomes of MOH patients after withdrawal therapy.

METHODS

Genotyping was conducted by polymerase chain reaction (PCR), PCR restriction fragment length polymorphism analysis or real-time PCR allelic discrimination assay on genomic DNA extracted from peripheral blood. Gene variants association was evaluated by logistic regression analysis adjusted for clinical confounding factors, and the threshold of statistical significance for multiple testing was set at P < 0.012.

RESULTS

Sixty-five MOH patients with unsuccessful detoxification and 83 MOH patients with effective drug withdrawal therapy were available for the analysis. rs4680G allele carriers or the COMT rs6269G-rs4680G haplotype were found to be associated with a lower risk of relapse within the first year after successful detoxification therapy, in comparison with homozygous rs4680A allele carriers [odds ratio (OR) 0.17, 95% confidence interval (CI) 0.05-0.61, P = 0.007] or with the COMT rs6269A-rs4680A haplotype (OR 0.19, 95% CI 0.06-0.54, P = 0.003), respectively. In addition, carriers of the STin2 VNTR short allele were found at higher odds for the composite poor outcome including unsuccessful withdrawal therapy and relapse within 12 months of follow-up after successful detoxification (OR 2.81, 95%CI 1.26-6.25, P = 0.009).

CONCLUSIONS

Our results indicate that genotyping for COMT rs4680 and SLC6A4 STin2 VNTR could be useful for the identification of MOH patients at higher risk of poor prognosis after drug withdrawal.

A consensus protocol for the management of medication-overuse headache: Evaluation in a multicentric, multinational study

INTRODUCTION

The management of medication-overuse headache (MOH) is often difficult and no specific guidelines are available as regards the most practical and effective approaches. In this study we defined and tested a consensus protocol for the management of MOH on a large population of patients distributed in different countries.

SUBJECTS AND METHODS

The protocol was based on evidence from the literature and on consolidated expertise of the members of the consensus group. The study was conducted according to a multicentric interventional design with the enrolment of 376 MOH subjects in four centres from Europe and two centres in Latin America. The majority of patients were treated according to an outpatient detoxification programme. The post-detoxification follow-up lasted six months.

RESULTS

At the final evaluation, two-thirds of the subjects were no longer overusers and in 46.5% of subjects headache had reverted back to an episodic pattern of headache. When comparing the subjects who underwent out-patient detoxification vs those treated with in-patient detoxification, both regimens proved effective, although the drop-out rate was higher in the out-patient approach.

CONCLUSIONS

The present findings support the effectiveness and usability of the proposed consensus protocol in different countries with different health care modalities.

Effects of CGRP receptor antagonism in nitroglycerin-induced hyperalgesia

Background

The release of calcitonin gene-related peptide (CGRP) from trigeminal nerves plays a central role in the pathophysiology of migraine and clinical evidence shows an antimigraine effect for CGRP receptor antagonists. Systemic administration of nitroglycerin (NTG), a nitrovasodilator, consistently provokes spontaneous-like migraine attacks in migraine sufferers; in the rat, systemic NTG induces a condition of hyperalgesia, probably through the activation of cerebral/spinal structures involved in nociceptive transmission.

Aim

The aim of this article is to test the analgesic effect of the CGRP receptor antagonist MK-8825 in two animal models of pain that may be relevant for migraine: the tail flick test and the formalin test performed during NTG-induced hyperalgesia.

Results

MK-8825 showed analgesic activity when administered alone at both the tail flick test and the formalin test. Furthermore, the CGRP antagonist proved effective in counteracting NTG-induced hyperalgesia in both tests. MK-8825 indeed reduced the nociceptive behavior when administered either simultaneously or prior to (30–60 minutes before) NTG.

Conclusion

These data suggest that MK-8825 may represent a potential therapeutic tool for the treatment of migraine.

Disability, anxiety and depression associated with medication-overuse headache can be considerably reduced by detoxification and prophylactic treatment. Results from a multicentre, multinational study (COMOESTAS project)

OBJECTIVE

The objective of this article is to investigate whether headache-related disability, depression and anxiety can be reduced by detoxification and prophylactic treatment in patients with medication-overuse headache (MOH).

METHODS

Patients with MOH were included from six centres in Europe and Latin America in a seven-month cohort study. Before and six months after treatment, the degree of disability was measured by the Migraine Disability Assessment (MIDAS) questionnaire, while anxiety and depression were measured by the Hospital Anxiety and Depression Scale (HADS).

RESULTS

A total of 694 patients with MOH were included, of whom 492 completed the study. Headache days were reduced by 58.4% from 23.6 to 9.8 days per month at six months ( P < 0.001). The MIDAS score was reduced by 57.1% from baseline 59.9 to 25.7 ( P < 0.001). Number of patients with depression was reduced by 50.7% from 195 to 96 and number of those with anxiety was reduced by 27.1% from 284 to 207 (both P < 0.001).

CONCLUSIONS

Disability, depression and anxiety were considerably reduced in patients with MOH by detoxification and prophylactic treatment. This emphasises the urgent need for increased awareness about avoiding overuse of headache medications and demonstrates that not only headache frequency but also disability are remarkably improved by adequate intervention.

Neuroprotection by leptin in a rat model of permanent cerebral ischemia: effects on STAT3 phosphorylation in discrete cells of the brain

In addition to its effects in the hypothalamus to control body weight, leptin is involved in the regulation of neuronal function, development and survival. Recent findings have highlighted the neuroprotective effects of leptin against ischemic brain injury; however, to date, little is known about the role performed by the signal transducer and activator of transcription (STAT)-3, a major mediator of leptin receptor transduction pathway in the brain, in the beneficial effects of the hormone. Our data demonstrate that systemic acute administration of leptin produces neuroprotection in rats subjected to permanent middle cerebral artery occlusion (MCAo), as revealed by a significant reduction of the brain infarct volume and neurological deficit up to 7 days after the induction of ischemia. By combining a subcellular fractionation approach with immunohistofluorescence, we observe that neuroprotection is associated with a cell type-specific modulation of STAT3 phosphorylation in the ischemic cortex. The early enhancement of nuclear phospho-STAT3 induced by leptin in the astrocytes of the ischemic penumbra may contribute to a beneficial effect of these cells on the evolution of tissue damage. In addition, the elevation of phospho-STAT3 induced by leptin in the neurons after 24 h MCAo is associated with an increased expression of tissue inhibitor of matrix metalloproteinases-1 in the cortex, suggesting its possible involvement to the neuroprotection produced by the adipokine.