Maintenance of response and predictive factors of 1-year GalcanezumAb treatment in real-life migraine patients in Italy: The multicenter prospective cohort GARLIT study.

BACKGROUND AND PURPOSE: To evaluate the 1-year effectiveness and tolerability of galcanezumab in real life and the prognostic indicators of persistent response. METHODS: High-frequency episodic migraine (HFEM) and chronic migraine (CM) patients treated with galcanezumab who completed a 1-year observation were enrolled. The primary outcomes assessed during the 12 months (V1-V12) were the change in monthly migraine days (MMDs) from baseline and the response rates ≥50% in MMDs (MMD ≥50% RR). The secondary outcomes were changes in pain intensity (numerical rating scale [NRS]) and in monthly acute medication intake (MAMI). RESULTS: We enrolled 191 patients (77.5% CM). Twenty-three patients (12%) dropped out, two for nonserious adverse events. At least 40% of patients took add-on standard preventives from baseline to V12. At V12, MMDs were reduced by 6.0 days in HFEM and by 11.9 days in CM patients (both p < 0.00001); NRS and MAMI were also decreased in both groups (p < 0.00001). One-hundred eight (56.5%) patients presented MMD ≥50% RR for 9 cumulative months (interquartile range=8): we defined this value as the cutoff for a persistent response. Persistent responders were less likely to have a higher body mass index (BMI) (p = 0.007) but more frequently had a good response to triptans (p = 0.005) and MMD ≥50% RR at V1 (p < 0.0000001). Patients without a persistent response were on add-on therapy for longer periods of time (p < 0.001). CONCLUSIONS: Galcanezumab was effective and well-tolerated in the 1-year term, with most patients presenting MMD ≥50% RR for at least 9 months. Triptan response, lower BMI, and MMD ≥50% RR in the first month emerged as predictive factors for a persistent response.

Early and sustained efficacy of fremanezumab over 24-weeks in migraine patients with multiple preventive treatment failures: the multicenter, prospective, real-life FRIEND2 study.

BACKGROUND: To verify the long-term (24-week) efficacy, safety, and tolerability of fremanezumab in real-life patients with high-frequency episodic migraine (HFEM: ≥ 8 days/month) or chronic migraine (CM: ≥ 15 days/month), and multiple preventive treatment failures. METHODS: This is a prospective, cohort, real-life study at 28 headache centers on consecutive patients affected by HFEM or CM with multiple preventive treatment failures who were prescribed subcutaneous fremanezumab (225 mg monthly/675 mg quarterly) for ≥ 24 weeks. Primary endpoint was the change in monthly migraine days (MMDs) in HFEM and monthly headache days (MHDs) in CM at weeks 21-24 compared to baseline. Secondary endpoints encompassed changes in monthly analgesic medications, ≥ 50%, ≥ 75%, and 100% responder rates, and variation in NRS, HIT-6 and MIDAS scores at the same time interval. Changes in MMDs/MHDs, monthly analgesic medications, ≥ 50%, ≥ 75%, and 100% responder rates, and variation in NRS and HIT-6 scores at week 4 were also monitored. RESULTS: Four hundred ten patients who had received ≥ 1 dose of fremanezumab were considered for safety analysis while 148 patients treated for ≥ 24 weeks were included in the efficacy analysis. At weeks 21-24, fremanezumab significantly (p < 0.001) reduced MMDs, MHDs, monthly analgesic medications and NRS, HIT-6, and MIDAS scores in both HFEM and CM compared to baseline. The proportions of ≥ 50%, ≥ 75% and 100% responders at weeks 21-24were 75.0%, 30.8%, 9.6% (HFEM), and 72.9, 44.8 and 1% (CM). A significant (p < 0.001) decrease in MMDs, MHDs, monthly analgesic medications and NRS, HIT-6, and MIDAS scores in both HFEM and CM was already present at week 4. The proportions of ≥ 50%, ≥ 75%, and 100% responders at week 4 were 67.6%, 32.4%, 11.8% (HFEM) and 67.3%, 40%, 1.8% (CM). CM remitted to episodic migraine and medication overuse to no-medication overuse in 83.3 and 75% of patients at week 24, and in 80 and 72.4% at week 4. Adverse events were rare (2.4%), mild and transient. No patient discontinued treatment for any reason. CONCLUSIONS: Fremanezumab is characterized by an early and sustained efficacy in HFEM and CM patients with multiple preventive treatment failures in real-life, revealing an optimal safety and tolerability profile.

Predictors of response to anti-CGRP monoclonal antibodies: a 24-week, multicenter, prospective study on 864 migraine patients.

BACKGROUND AND OBJECTIVES: The identification of predictors of response to antiCGRP mAbs could favor tailored therapies and personalized treatment plans. This study is aimed at investigating predictors of ≥ 50%, ≥ 75% and 100% response at 24 weeks in patients with high-frequency episodic (HFEM: 8-14 days/month) or chronic migraine (CM). METHODS: This is a large, multicenter, cohort, real-life study. We considered all consecutive adult patients affected by HFEM or CM who were prescribed antiCGRP mAbs for ≥ 24 weeks in 20 headache centers. Patients were interviewed face-to-face using a shared semi-structured questionnaire carefully exploring socio-demographic and clinical characteristics. Patients received subcutaneous erenumab (70 mg or140 mg, monthly), galcanezumab (120 mg monthly, following a 240 mg loading dose), or fremanezumab (225 mg, monthly or 675 mg, quarterly) according to drug market availability, physician's choice, or patient's preference. The primary endpoint of the study was the assessment of ≥ 50% response predictors at 24 weeks. Secondary endpoints included ≥ 75% and 100% response predictors at 24 weeks. RESULTS: Eight hundred sixty-four migraine patients had been treated with antiCGRP mAbs for ≥ 24 weeks (erenumab: 639 pts; galcanezumab: 173 pts; fremanezumab: 55 pts). The ≥50% response (primary endpoint) in HFEM was positively associated with unilateral pain (UP) + unilateral cranial autonomic symptoms (UAs) (OR:4.23, 95%CI:1.57-11.4; p = 0.004), while in CM was positively associated with UAs (OR:1.49, 95%CI:1.05-2.11; p = 0.026), UP + UAs (OR:1.90, 95%CI:1.15-3.16; p = 0.012), UP + allodynia (OR:1.71, 95%CI:1.04-2.83; p = 0.034), and negatively associated with obesity (OR:0.21, 95%CI:0.07-0.64; p = 0.006). The 75% response (secondary endpoint) was positively associated with UP + UAs in HFEM (OR:3.44, 95%CI:1.42-8.31; p = 0.006) and with UP + UAs (OR:1.78, 95%CI:1.14-2.80; p = 0.012) and UP + allodynia (OR:1.92, 95%CI:1.22-3.06; p = 0.005) in CM. No predictor of 100% response emerged in patients with HFEM or CM. CONCLUSIONS: A critical evaluation of headache characteristics indicating peripheral or central sensitization may help in predicting responsiveness to antiCGRP mAbs in HFEM and CM. A more precise pain profiling may represent a steppingstone for a mechanism-based approach and personalized treatment of migraine with compounds targeting specific molecular mechanisms.

Galcanezumab for the prevention of high frequency episodic and chronic migraine in real life in Italy: a multicenter prospective cohort study (the GARLIT study).

BACKGROUND: The clinical benefit of galcanezumab, demonstrated in randomized clinical trials (RCTs), remains to be quantified in real life. This study aimed at evaluating the effectiveness, safety and tolerability of galcanezumab in the prevention of high-frequency episodic migraine (HFEM) and chronic migraine (CM) in a real-life setting. METHODS: This multicenter prospective observational cohort study was conducted between November 2019 and January 2021 at 13 Italian headache centers. Consecutive adult HFEM and CM patients clinically eligible were enrolled and treated with galcanezumab subcutaneous injection 120 mg monthly with the first loading dose of 240 mg. The primary endpoint was the change in monthly migraine days (MMDs) in HFEM and monthly headache days (MHDs) in CM patients after 6 months of therapy (V6). Secondary endpoints were the Numerical Rating Scale (NRS), monthly painkiller intake (MPI), HIT-6 and MIDAS scores changes, ≥50% responder rates (RR), the conversion rate from CM to episodic migraine (EM) and Medication Overuse (MO) discontinuation. RESULTS: One hundred sixty-three patients (80.5% female, 47.1 ± 11.7 years, 79.8% CM) were included. At V6, MMDs reduced by 8 days in HFEM and MHDs by 13 days in CM patients (both p < .001). NRS, MPI, HIT-6 and MIDAS scores significantly decreased (p < .001). Ten patients (6.1%) dropped out for inefficacy and classified as non-responders. Patients with ≥50%RRs, i.e. responders, were 76.5% in the HFEM and 63.5% in the CM group at V6. Among CM patients, the V6 responders presented a lower body mass index (p = .018) and had failed a lower number of preventive treatments (p = .013) than non-responders. At V6, 77.2% of CM patients converted to EM, and 82.0% ceased MO. Adverse events, none serious, were reported in up to 10.3% of patients during evaluation times. CONCLUSIONS: Galcanezumab in real life was safe, well tolerated and seemed more effective than in RCTs. Normal weight and a low number of failed preventives were positively associated with galcanezumab effectiveness in CM patients. TRIAL REGISTRATION: ClinicalTrials.gov NCT04803513 .

Demographic and clinical determinants of neck pain in idiopathic cervical dystonia.

Cervical dystonia is associated with neck pain in a significant proportion of cases, but the mechanisms underlying pain are largely unknown. In this exploratory study, we compared demographic and clinical variables in cervical dystonia patients with and without neck pain from the Italian Dystonia Registry. Univariable and multivariable logistic regression analysis indicated a higher frequency of sensory trick and a lower educational level among patients with pain.

Abnormal tyrosine metabolism in chronic cluster headache.

Objective Episodic cluster headache is characterized by abnormalities in tyrosine metabolism (i.e. elevated levels of dopamine, tyramine, octopamine and synephrine and low levels of noradrenalin in plasma and platelets.) It is unknown, however, if such biochemical anomalies are present and/or constitute a predisposing factor in chronic cluster headache. To test this hypothesis, we measured the levels of dopamine and noradrenaline together with those of elusive amines, such as tyramine, octopamine and synephrine, in plasma of chronic cluster patients and control individuals. Methods Plasma levels of dopamine, noradrenaline and trace amines, including tyramine, octopamine and synephrine, were measured in a group of 23 chronic cluster headache patients (10 chronic cluster ab initio and 13 transformed from episodic cluster), and 16 control participants. Results The plasma levels of dopamine, noradrenaline and tyramine were several times higher in chronic cluster headache patients compared with controls. The levels of octopamine and synephrine were significantly lower in plasma of these patients with respect to control individuals. Conclusions These results suggest that anomalies in tyrosine metabolism play a role in the pathogenesis of chronic cluster headache and constitute a predisposing factor for the transformation of the episodic into a chronic form of this primary headache.

Onabotulinumtoxin A for the management of chronic migraine in current clinical practice: results of a survey of sixty-three Italian headache centers.

BACKGROUND: Chronic migraine is a complex clinical condition often undertreated. Onabotulinumtoxin A (OBT-A) was approved in Italy in 2013 for symptom relief in patients with chronic migraine who have failed, or do not tolerate, oral prophylactic treatments. However, the impact of OBT-A in clinical practice remains to be defined. METHODS: To investigate the current management of chronic migraine with OBT-A in clinical practice, a web-based survey was conducted among clinicians working in third-level headache centers across Italy. A 26-item questionnaire was designed and developed by a group of 10 Italian headache specialists to address the following issues: treatment paradigm and OBT-A injection intervals, frequency of treatment and retreatment, definition of responders/non-responders, satisfaction with treatment potential impact of early treatment with OBT-A. Ninety-six headache centers were selected and contacted via e-mail. The online survey was anonymous and carried out using a secure website. RESULTS: Overall, 64 of the 96 centers (66.7%) completed the questionnaire. Most centers (98.4%) had been using OBT-A for >1 year. OBT-A was administered according to the PREEMPT paradigm in most centers (88.9%). While during the first year of prophylaxis with OBT-A most clinicians (93.6%) repeated OBT-A treatment every 3 months, as recommended, in the following years interval duration was variable. Response to OBT-A was defined as a ≥ 50% reduction in the headache days by 58.7% of the clinicians, and as a ≥ 30% reduction by 25.4% of them. Almost 60% of the clinicians considered OBT-A as a long-lasting therapy, while for one-third of them treatment could be discontinued in patients showing a benefit for ≥6 months. According to 80% of the clinicians, early administration of OBT-A after the onset of chronic migraine was associated with better outcomes, and 47.6% felt that OBT-A should be recommended as a first-line option. CONCLUSIONS: This survey indicates that in third-level headache centers in Italy OBT-A is used in good compliance with current recommendations. There is agreement about the definition of response as a reduction in headache days by 30% to 50%. Additional effort is required to define response to OBT-A and to establish optimal treatment duration.

Prevalence of Patent Foramen Ovale in Ischaemic Stroke in Italy: Results of SISIFO Study.

BACKGROUND: Although several authors have studied the association between patent foramen ovale (PFO) and ischaemic stroke, the matter is still controversial; few have suggested an association between cryptogenetic stroke and PFO, while others have denied this association. The aim of this study was to evaluate PFO prevalence in the whole ischaemic stroke population, independently from age and stroke subtypes and to identify the characteristics associated with the presence of PFO. METHODS: SISIFO study was a multicenter, prospective, single-wave, cross-sectional survey conducted on consecutive patients with acute ischemic stroke admitted to selected clinical centres. Data regarding vascular risk factors were registered for each patient; all patients underwent computed tomography scan and/or magnetic resonance imaging of the brain; an electrocardiogram and standard laboratory blood tests were performed. A Doppler ultrasound study of extra-cranial arteries was performed too. The cases were classified according to TOAST and OCSP criteria. Each patient underwent transcranial Doppler or transcranial color-coded duplex sonography with bubble test as diagnostic tool for right-to-left-shunt. Where right-to-left shunt was detected, PFO presence was confirmed by echocardiography. FINDINGS: 1,130 consecutive patients were included. We found a PFO in 247 (21.9%; 95% CI, 19.5-24.3%) patients; PFO was present in 23.5% of patients with cryptogenic stroke and in 21.3% of patients with stroke of known causes; this difference was not statistically significant. At the univariate analysis, decreasing age, hypertension, diabetes mellitus, and atrial fibrillation, and stroke characteristics such as NIHSS, OCSP and TOAST were predictors of PFO presence. At the multivariate analysis, we found a significant interaction between age and OCSP syndrome. Being LACI the reference category, the prevalence of PFO in PACI and POCI decreased significantly along with age, whereas there was no change in TACI. CONCLUSION: If any relationship exists between stroke and PFO, this is more likely in PACI and POCI at a younger age. Our results are consistent with recent findings that underline PFO alone must not be considered a significant independent predictor for stroke; so the presence of PFO alone doesn't permit rushed causal correlations or 'therapeutic aggressiveness'.

The painful muse: migrainous artistic archetypes from visual cortex.

Neurological diseases which constituted traditionally obstacles to artistic creation can, in the case of migraine, be transformed by the artists into a source of inspiration and artistic production. These phenomena represent a chapter of a broader embryonic neurobiology of painting.

Efficacy of frovatriptan and other triptans in the treatment of acute migraine of normal weight and obese subjects: a review of randomized studies.

An association between obesity and migraine has been observed in recent studies and it is supported by plausible biological mechanisms. The objective of this study is to evaluate the efficacy of frovatriptan and other triptans in the acute treatment of migraine, in patients enrolled in three randomized, double-blind, crossover, Italian studies and classified according to body mass index (BMI) levels, as normal weight or non-obese (NO, BMI 18.5-24.9 kg/m(2)) and overweight or obese subjects (O, BMI ≥ 25 kg/m(2)). 414 migraineurs with or without aura were randomized to frovatriptan 2.5 mg or rizatriptan 10 mg (study 1), frovatriptan 2.5 mg or zolmitriptan 2.5 mg (study 2), frovatriptan 2.5 mg or almotriptan 12.5 mg (study 3). After treating up to three episodes of migraine in 3 months with the first treatment, patients switched to the alternate treatment for the next 3 months. The present analysis assessed triptan efficacy in 220 N and in 109 O subjects of the 346 individuals of the intention-to-treat population. The proportion of pain free at 2 h did not significantly differ between frovatriptan and the comparators in either NO (30 vs. 34 %) or O (24 vs. 27 %). However, the rate of pain free at 2 h was significantly (p < 0.05) larger in NO than in O, irrespective of the type of triptan. Pain relief at 2 h was also similar between drug treatments for either subgroup. Pain relapse occurred at 48 h in significantly (p < 0.05) fewer episodes treated with frovatriptan in both NO (26 vs. 36 %) and O (27 vs. 49 %). The rate of 48-h relapse was similar in NO and O with frovatriptan, while it was significantly (p < 0.05) higher in O with the comparators. Frovatriptan, in contrast to other triptans, retains a sustained antimigraine effect in NO and even more so in O subjects.

Tryptamine levels are low in plasma of chronic migraine and chronic tension-type headache.

The primary aim of this study (TA-CH, Tryptophan Amine in Chronic Headache) was to investigate a possible role of tryptophan (TRP) metabolism in chronic migraine (CM) and chronic tension-type headache (CTTH). It is not known if TRP metabolism plays any role in CM and/or CTTH. Plasma levels of serotonin (5-HT), 5-hydroxyindolacetic acid (5-HIAA), metabolite of 5-HT, and tryptamine (TRY) were tested in 73 patients with CM, 15 patients with CTTH and 37 control subjects. Of these, plasmatic TRY was significantly lower in CM (p < 0.001) and in CTTH (p < 0.002) patients with respect to control subjects, while 5-HIAA levels in plasma were within the same range in all groups. 5-HT was undetectable in the plasma of almost all subjects. Our results support the hypothesis that TRP metabolism is altered in CM and CTTH patients, leading to a reduction in plasma TRY. As TRY modulates the function of pain matrix serotonergic system, this may affect modulation of incoming nociceptive inputs from the trigeminal endings and posterior horns of the spinal cord. We suggest that these biochemical abnormalities play a role in the chronicity of CM and CTTH.

Prevalence of patent foramen ovale in ischemic stroke in Italy: the SISIFO study.

Patent foramen ovale (PFO) is a common congenital anatomical defect in the general population with a mean prevalence of 20 %. Transcranial Doppler sonography and echocardiography, both with infusion of agitated saline as an echo contrast, have been introduced for the diagnosis of PFO. Transesophageal echocardiography is considered the gold standard. Several studies have suggested an association between cryptogenetic stroke and PFO, but the role of this condition as a risk factor for stroke is still debated. The aims of this prospective multicentre study are the evaluation of PFO prevalence in the whole ischemic stroke population and the identification of a stroke recurrence profile risk in patients with PFO. All consecutive patients admitted for acute ischemic stroke and with a confirmed diagnosis at discharge are eligible cases for the study. Demographic and vascular risk factors are registered. Clinical severity is summarized by the National Institute of Health stroke scale. Echocardiographic and transcranial studies are performed in each patient to detect the presence of PFO. Prevalence of PFO will be calculated with 95 % CIs. Univariate analysis will be performed to detect the correlation of PFO with different registered factors and multivariable analysis with PFO as independent variable. The present study should contribute to better identify the role of PFO in ischemic stroke risk and recurrence-related events. Qualifying findings of the study are represented by the high number of enrolled patients, the prospective methodology of the study and the presence of secondary instrumental endpoints.

Ultra-late response (> 24 weeks) to anti-CGRP monoclonal antibodies in migraine: a multicenter, prospective, observational study.

OBJECTIVE: Nearly 60% of migraine patients treated with monoclonal antibodies (mAbs) targeting the calcitonin gene-related peptide (CGRP) pathway experience a ≥ 50% reduction in monthly migraine days (MMD) at 12 weeks compared to baseline (responders). However, approximately half of the patients not responding to anti-CGRP mAbs ≤ 12 weeks do respond ≤ 24 weeks (late responders). We assessed frequency and characteristics of patients responding to anti-CGRP mAbs only > 24 weeks (ultra-late responders). METHODS: In this multicenter (n = 16), prospective, observational, real-life study, we enrolled all consecutive adults affected by high-frequency episodic migraine (HFEM: ≥ 8 days/month) or chronic migraine (CM), with ≥ 3 prior therapeutic failures, treated with any anti-CGRP mAbs for ≥ 48 weeks. We defined responders patients with a ≥ 50% response rate ≤ 12 weeks, late responders those with a ≥ 50% response rate ≤ 24 weeks, and ultra-late responders those achieving a ≥ 50% response only > 24 weeks. RESULTS: A total of 572 migraine patients completed ≥ 48 weeks of anti-CGRP mAbs treatment. Responders accounted for 60.5% (346/572), late responders for 15% (86/572), and ultra-late responders for 15.7% (90/572). Among ultra-late responders, 7.3% (42/572) maintained the ≥ 50% response rate across all subsequent time intervals (weeks 28, 32, 36, 40, 44, and 48) and were considered persistent ultra-late responders, while 8.4% (48/572) missed the ≥ 50% response rate at ≥ 1 subsequent time interval and were classified as fluctuating ultra-late responders. Fifty patients (8.7%) did not respond at any time interval ≤ 48 weeks. Ultra-late responders differed from responders for higher BMI (p = 0.033), longer duration of medication overuse (p < 0.001), lower NRS (p = 0.017) and HIT-6 scores (p = 0.002), higher frequency of dopaminergic symptoms (p = 0.002), less common unilateral pain-either alone (p = 0.010) or in combination with UAS (p = 0.023), allodynia (p = 0.043), or UAS and allodynia (p = 0.012)-a higher number of comorbidities (p = 0.012), psychiatric comorbidities (p = 0.010) and a higher proportion of patients with ≥ 1 comorbidity (p = 0.020). CONCLUSION: Two-thirds of patients not responding to anti-CGRP mAbs ≤ 24 weeks do respond later, while non-responders ≤ 48 weeks are quite rare (8.7%). These findings suggest to rethink the duration of migraine prophylaxis and the definition of resistant and refractory migraine, currently based on the response after 2-3 months of treatment.

Assessing the Long-Term (48-Week) Effectiveness, Safety, and Tolerability of Fremanezumab in Migraine in Real Life: Insights from the Multicenter, Prospective, FRIEND3 Study.

INTRODUCTION: Long-term (1-year) fremanezumab treatment proved to be effective, safe, and well tolerated in individuals with migraine and < 2 medication clusters in a randomized controlled trial (RCT). We aimed to assess real-world evidence (RWE), long-term effectiveness, tolerability, and safety of fremanezumab in people with high-frequency episodic migraine (HFEM) or chronic migraine (CM) with > 3 treatment failures and various comorbidities. METHODS: A 48-week, prospective, multicenter (n = 26), cohort study assessed fremanezumab's effectiveness, safety, and tolerability in consecutive adults with HFEM or CM with > 3 treatment failures. Primary endpoint was variation from baseline in monthly migraine days (MMD) in HFEM and monthly headache days (MHD) in CM at weeks 45-48. Secondary endpoints were changes in monthly analgesic medications, Numerical Rating Scale (NRS), Headache Impact Test (HIT-6), and the Migraine Disability Assessment Scale (MIDAS) scores and ≥ 50%, ≥ 75%, and 100% responder rates. RESULTS: Of 533 participants who had received ≥ 1 fremanezumab dose, 130 were treated for ≥ 48 weeks and considered for effectiveness analysis. No participant missed any treatment dosage every other consecutive month during the 12-month period. PRIMARY ENDPOINT: fremanezumab significantly (p < 0.001) reduced both MMD (- 6.4) in HFEM and MHD (- 14.5) in CM. Secondary endpoints: a significant reduction (p < 0.001) was observed in monthly analgesic medications (HFEM - 6.0; CM -16.5), NRS (HFEM - 3.4; CM - 3.4), HIT-6 (HFEM - 16.9; CM - 17.9) and MIDAS score (HFEM - 50.4; CM - 76.6). The ≥ 50%, ≥ 75%, and 100% response rates to fremanezumab were 75.5%, 36.7%, and 2% in HFEM and 71.6%, 44.4%, and 3.7% in CM. Corresponding response rates were 60.5%, 37.2%, and 2.3% in individuals with psychiatric comorbidities, 74.2%, 50%, and 4.8% in CM with medication overuse, and 60.9%, 39.1%, and 4.3% in CM with medication overuse and psychiatric comorbidities. Mild and transient treatment-emergent adverse events occurred in 7.8% of the participants. No subject discontinued the treatment for any reason. CONCLUSION: This RWE study documents that long-term fremanezumab treatment is highly effective and remarkably well tolerated in subjects with HFEM or CM with multiple (> 3) therapeutic failures, even in the presence of concomitant medication overuse, psychiatric comorbidities, or both. The effectiveness-to-tolerability ratio appears to be better in RWE than in RCTs.

The role of tyrosine metabolism in the pathogenesis of chronic migraine.

OBJECTIVE: The pathogenesis of chronic migraine (CM) remains largely unknown. We hypothesized that anomalies of tyrosine metabolism, found in migraine without aura (MwwA) patients, play an important role in the transformation of MwwA into CM, since the increase in the number of MwwA attacks is the most predisposing factor for the occurrence of CM. METHODS: To test our hypothesis we measured the plasma levels of dopamine (DA), noradrenaline (NE) and trace amines, including tyramine (TYR) and octopamine (OCT), in a group of 73 patients with CM, 13 patients with chronic tension-type headache (CTTH) and 37 controls followed in the Headache Centers of the Neurology Departments of Asti, Milan and Vicenza hospitals in Italy. RESULTS: The plasma levels of DA and NE were several-fold higher in CM patients compared with control subjects ( P > 0.001). The plasma levels of TYR were also extremely elevated ( P > 0.001); furthermore, these levels progressively increased with the duration of the CM. CONCLUSIONS: Our data support the hypothesis that altered tyrosine metabolism plays an important role in the pathogenesis of CM. The high plasma levels of TYR, a potent agonist of the trace amine associated receptors type 1 (TAAR1), may ultimately down-regulate this receptor because of loss of inhibitory presynaptic regulation, therein resulting in uncontrolled neurotransmitter release. This may produce functional metabolic consequences in the synaptic clefts of the pain matrix implicated in CM.

Sensitization and pain.

Migraine is often accompanied with signs of increased intracranial and extracranial mechanical sensitivities. The prevailing view today is that migraine headache is a neurovascular disorder with intracranial origin and involvement of meningeal blood vessels and their pain nerve fibers. Allodynia, defined as perception of pain following not painful stimulation, is a common clinical feature in various pain syndromes, and as part of migraine pain, it can be considered an indicator of trigeminal neural network sensitization. The cutaneous allodynia that accompanies the migraine headache in a large percentage of patients may be considered the clinical expression of central nervous system sensitization and is characterized by pain provoked by stimulation of the skin that would ordinarily not produce pain. An altered codification process of sensory impulses in the brainstem, in particular by the nucleus caudalis trigeminalis, may justify the temporal aspects and symptoms in the course of migraine attack.

Allodynia and migraine.

An impaired processing of sensory afferents in the brainstem plays a key role in the development of migraine attack and for many of its clinical aspects. The repetition or prolonged of painful stimuli over time would be able to produce a prolonged and reversible increase of excitability and synaptic efficacy in the nociceptive pathways of the central nervous system. This phenomenon, known as sensitization, involves specifically the caudal trigeminal nucleus. Being an aspect of untreated migraine, allodynia is more common in patients with chronic migraine and migraine with aura, often associated with motor and sensory symptoms sometimes present during the attacks. The presence of allodynia in the course of migraine attack greatly increases the disability of the patient and its recognition, as well as from a therapeutic point of view, it is essential in the management of migraine patients.