Plasma CGRP but not PACAP-38 concentrations are associated with response to anti-CGRP monoclonal antibodies in migraine

BackgroundAn increasing number of studies have suggested that the important role of vasoactive peptides, such as pituitary adenylate cyclase-activating polypeptide-38 (PACAP-38) and calcitonin gene-related peptide (CGRP), in the pathophysiology of migraine seems undeniable in adults, but studies in pediatric migraine patients remain scarce. We prospectively investigated CGRP and PACAP-38 plasma levels in children with migraine during ictal and interictal periods and compared the results between migraine patients with aura and without aura. We were the first to explore the diagnostic value of a combination of CGRP and PACAP-38.MethodsSeventy-six migraine patients aged 4–18 years and seventy-seven age-matched healthy children were included in the study. Plasma vasoactive peptides were measured using the enzyme-linked immunosorbent assay (ELISA). Differences and correlations of groups were analyzed using the independent samples t-test, analysis of variance (ANOVA), Mann-Whitney U test, and multiple linear regression. We also performed logistic regression and receiver operating characteristic curve (ROC) analyses to evaluate the diagnostic value of CGRP and PACAP-38 in pediatric migraine.ResultsPACAP-38 and CGRP levels in migraine patients during the ictal and interictal periods were higher than those in controls (p < 0.001). PACAP-38 and CGRP levels in migraine patients with aura and without aura were higher than those in controls (p < 0.001). PACAP-38 and CGRP were independent risk factors in diagnosing pediatric migraine (adjusted OR (PACAP-38) =1.331, 95% CI: 1.177–1.506, p < 0.001; adjusted OR (CGRP) = 1.113, 95% CI: 1.064–1.165, p < 0.001). Area Under Curve (AUC) comparison: Combination (0.926) > CGRP (0.869) > PACAP-38 (0.867).ConclusionsOur study found almost the same changes in CGRP and PACAP levels in pediatric migraine, suggesting that CGRP and PACAP-38 may work together to play an integral role in pediatric migraine. Higher CGRP levels were found in the ictal phase than in the interictal phase and with aura group than without aura group, indicating that CGRP may take part in the formation of pain and aura. Moreover, ROC and logistic regression analyses suggested that CGRP and PACAP-38 are good indicators to diagnose pediatric migraine, and the combination of CGRP and PACAP-38 was valuable in diagnosing pediatric migraine and differentiating pediatric migraine from non-migraine headaches.Trial registrationThe study has been registered at the Chinese Clinical Trial Registry (ChiCTR2100043157).

Migraine is one of the most disabling diseases that continues to pose a significant societal burden. Although there are now treatment options for people with migraine, it remains challenging to identify them as clinical features are diverse and complex, and there are no validated diagnostic or treatment prediction biomarkers. Identification is based on either diagnostic coding or the use of certain acute headache abortive treatments. However, socioeconomic disparities can contribute to under-diagnosis and under-treatment of migraine. Thus, efforts to find biomarkers to identify individuals with migraine and which variables could explain migraine-related chronification and disability are warranted. We aimed to investigate the levels of migraine inducing neuropeptides; calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating polypeptide (PACAP) in peripheral blood samples as potential biomarkers of migraine. We developed highly sensitive assays for CGRP and PACAP on the MSD S-PLEX assay platform and used them for bioanalysis of preclinical and clinical samples. Wildtype and neuropeptide challenged mice and rats were profiled using the developed assay. To follow-up, commercially obtained plasma samples from healthy controls and migraineurs were initially profiled. Subsequently, we profiled plasma samples from people with migraine (during and after a headache attack and healthy controls. Both MSD S-PLEX assays were transferred to Celerion where they were validated for analysis of clinical samples. Using the highly sensitive PACAP assay, we were able to reliably measure circulating levels of endogenous and administrated PACAP38in mouse and rat plasma. Additionally, using the highly sensitive CGRP assay, we were able to reliably measure circulating levels of endogenous and administrated CGRP in mouse and rat plasma. Furthermore, in the initial human samples, circulating CGRP and PACAP levels were not significantly different in healthy controls compared to people with migraine patients. However, ≥50% people with migraine showed increased circulating CGRP and PACAP levels during their attack period compared to post attack. Overall, people with migraine showed a 3 - 396% increase in one or both neuropeptides during their attack period compared to post attack. Circulating plasma CGRP and PACAP levels in healthy control subjects were consistent with previously measured levels. Our highly sensitive PACAP and CGRP assays were successful in measuring circulating levels of endogenous PACAP38 and CGRP in mouse and rat plasma. Our highly sensitive PACAP and CGRP assays were qualified for measurement of human CGRP and PACAP in healthy control and migraine samples. Plasma CGRP and PACAP levels are elevated in migraineurs during an attack period, and the increased plasma neuropeptide levels during an attack may help the differentiation of migraineurs from non-Migraineurs, or amongst people with migraines to help identify the best treatment for each patient.

BackgroundFew studies have examined plasma calcitonin gene-related peptide (CGRP) levels in individuals with vestibular migraine (VM), with inconsistent findings. Additionally, salivary CGRP levels in VM have not been reported.MethodsInterictal plasma and salivary CGRP levels were measured using an enzyme-linked immunosorbent assay in participants with VM corresponding to episodic migraine (VM, n = 81), chronic migraine without vestibular symptoms (CM, n = 73) and healthy controls (HC, n = 59).ResultsPlasma CGRP levels in VM with episodic migraine participants were significantly lower than those in participants with CM (median = 37.1 pg/mL, interquartile range (IQR) = 22.4-60.4 pg/mL vs. median = 74.6 pg/mL, IQR = 49.6-101.6 pg/mL; p < 0.001) but did not significantly differ from levels in HC. Similarly, salivary CGRP levels were also significantly lower in VM compared to CM (median = 54.5 pg/mL, IQR = 37.0-83.4 pg/mL vs. median = 72.0 pg/mL, IQR = 56.5-96.2 pg/mL; p = 0.036), with no significant difference observed between VM and HC. Receiver operating characteristic analysis showed that plasma CGRP levels effectively differentiated CM from VM corresponding to episodic migraine, achieving an area under the curve of 0.88. No significant correlations were found between plasma or salivary CGRP levels and clinical features of CM and VM.ConclusionsInterictal plasma and salivary CGRP levels are unlikely to serve a biomarkers for VM.

Background: Calcitonin Gene-Related Peptide (CGRP), Vasoactive Intestinal Peptide (VIP), and Pituitary Adenylate Cyclase-Activating Peptide (PACAP) play a crucial role in migraine pathophysiology. In recent years, anti-CGRP(R) monoclonal antibodies (mAbs) have emerged as the first targeted and highly effective therapy for migraine. This study aimed to assess plasma levels of these neuropeptides before and after prophylactic treatment with anti-CGRP(R) mAbs, evaluating potential changes after therapy and identifying predictors of treatment response Methods: Between February 2022 and February 2023, we enrolled 56 migraine patients who initiated prophylaxis with either erenumab (26 patients), galcanezumab (16 patients), or fremanezumab (14 patients). Responders were defined as those achieving a ≥50% reduction in monthly migraine days (MMDs) after six months. Blood samples were collected at baseline and at each follow-up visit (baseline T0, 3 months T1, 6 months T2, 12 months T3). Plasma levels of CGRP, VIP, and PACAP were measured using a validated radioimmunoassay (RIA) and commercially available enzyme-linked immunosorbent assay (ELISA) kits. Results: Overall, 80.3% (45 out of 56) of patients responded to anti-CGRP(R) mAbs. In patients treated with erenumab, CGRP levels did not show a significant change over the treatment period; however, responders exhibited a decreasing trend from T0 to T2 compared to non-responders. In the galcanezumab group, CGRP levels significantly decreased as early as T1 (p &lt; 0.01). Conversely, in the fremanezumab group, we observed a rapid increase in CGRP plasma levels above 3000 pg/ml, which was deemed unreliable due to assay interference from fremanezumab. VIP and PACAP levels remained stable over time, with no significant differences between responders and non-responders Conclusion: Anti-CGRP(R) mAbs are very effective migraine prophylaxes. Galcanezumab reduced CGRP plasmatic levels already after three months, while erenumab did not affect significantly CGRP plasmatic levels. VIP and PACAP levels were not influenced by the therapy.

High plasma calcitonin gene-related peptide and serum pituitary adenylate cyclase-activating polypeptide levels in patients with neuropathic pain

Calcitonin gene-related peptide (CGRP) is involved in the pathophysiology of migraine and cluster headache. Whether CGRP has any role in chronic tension-type headache is unknown. To compare interictal plasma levels of CGRP between patients with chronic tension-type headache and healthy control subjects, to investigate plasma CGRP in relation to headache state, and to compare plasma CGRP between the peripheral and the cranial circulation. Blood from the antecubital vein was drawn from 30 patients with chronic tension-type headache and 34 healthy control subjects. In addition, blood samples from the consecutive first 15 patients and from the consecutive first 20 healthy control subjects were also collected from the external jugular vein. CGRP levels measured in the peripheral circulation in patients on days without headache, 63+/-5 pmol/L, tended to be higher than CGRP levels in control subjects, 53+/-3 pmol/L (p = 0.06). In patients, no differences were found between CGRP levels assessed ictally and interictally in either the cranial (p = 0.91) or the peripheral (p = 0.62) circulation. Plasma CGRP level was higher in the external jugular vein than in the antecubital vein on days without headache (p = 0.03) but not on days with headache (p = 0.82). In control subjects, CGRP levels in the cranial circulation did not differ from CGRP levels in the peripheral circulation (p = 0.92). Exploratory analyses showed that 8 patients whose usual headache quality was throbbing had a higher interictal plasma CGRP level than control subjects (p = 0.002), whereas plasma CGRP level was normal in 22 patients with pressing headaches (p = 0.36). Plasma levels of CGRP are normal in patients with chronic tension-type headache and are unrelated to headache state. Interictal plasma CGRP was increased in patients with a pulsating pain quality. Because the authors have previously shown a similar increase of interictal CGRP levels in migraine, this study suggests that headaches with symptoms that fulfill International Headache Society criteria for tension-type headache may be pathophysiologically related to migraine, if the headache has a pulsating quality.

Calcitonin gene-related peptide (CGRP) has positive chronotropic and inotropic effects in animals and humans, and produces the most potent vasodilation known for an endogenous peptide. Yet, a physiological role for CGRP in the regulation of vascular tone and blood pressure has not been demonstrated. We studied the effects of 1) assumption of the upright position and 2) iv infusion of angiotensin-II (sequential doses of 8, 16, and 32 ng/kg.min, each dose for 20 min) in eight normal subjects (four men). Serial venous blood samples were taken to determine the plasma CGRP, epinephrine, norepinephrine, and aldosterone levels and PRA. Blood pressure and heart rate were continuously monitored at the finger with a Finapres 2300 instrument. After assumption of the upright posture, a quick rise in plasma CGRP levels was observed together with the expected increases in plasma norepinephrine and aldosterone and PRA. A transient increment was also observed for diastolic blood pressure and heart rate. Angiotensin-II infusion caused dose-dependent increases in plasma CGRP and aldosterone concentrations, already significant at the lowest infusion rate and parallel with the blood pressure rise. Plasma catecholamines significantly increased only at higher infusion rates. Our data demonstrate that modifications of plasma CGRP concentrations are part of the normal response to postural and vasomotor changes. These findings suggest a physiological role for CGRP in regulation of the peripheral vascular tone and possibly blood pressure in man.

Dihydroergotamine and sumatriptan attenuate levels of CGRP in plasma in rat superior sagittal sinus during electrical stimulation of the trigeminal ganglion

Circulating calcitonin gene-related peptide and its placental origins in normotensive and preeclamptic pregnancies

Typical modifications of cardiovascular activity and water and salt homeostasis throughout female reproductive life are well known. Differences in plasma levels of calcitonin gene-related peptide (CGRP) and atrial natriuretic peptide (ANP) have been observed in conditions characterized by different estrogenic levels, suggesting a correlation between female reproductive function and these cardiovascular hormones. The aim of our study was to investigate in hypothalamic amenorrhea the relationship between estrogen deficiency and plasma ANP and CGRP response to adaptive tests (saline infusion test and upright posture test, respectively). Women with hypothalamic amenorrhea (aged 18-28 years) (n = 6) and age-matched healthy controls (n = 6) underwent both functional tests. Plasma CGRP and ANP levels were measured by specific radioimmunoassays before and in course of the tests. Basal plasma CGRP levels of amenorrheic patients did not significantly differ from those of normal women, while basal plasma ANP levels were significantly higher compared to controls (p < 0.01). In amenorrheic women, plasma CGRP levels showed a significant increase in response to upright posture test, though lower than the increase observed in normal women. In contrast, saline infusion test determined a significant increase in plasma ANP levels only in control subjects. In women with hypothalamic amenorrhea, the altered response of CGRP and ANP to adaptive stimuli indicates a partial derangement in the control of the secretion of these cardiovascular hormones. Nevertheless, the differences between such modifications and those observed in other conditions of altered estrogenic levels, suggest that in amenorrheic women hypogonadism is not the major factor influencing CGRP and ANP response to adaptive stimuli.

Plasma level of calcitonin gene-related peptide in patients with polycystic ovary syndrome and its relationship to hormonal and metabolic parameters

Objective To evaluate the pathophysiological role of calcitonin gene-related peptide(CGRP) and substance P(SP) in patients with chronic cor pulmonale. Methods The levels of plasma CGRP and SP were determined by radioimmunoassay in 30 patients with chronic cor pulmonale before and after treatment, and their mean pulmonary aterial pressure(PaO2) were detected. Control group consisted of 20 healthy subjects and the levels of plasma CGRP and cor pulmonale group, plasma CGRP levels before treatment(12±5 pg/ml)were lower than those after treatment(19±7)pg/ml(P<0.01). Both of them were lower than those in control group(24±5)pg/ml(P<0.01). Plasma SP levels before treatment(39±12)pg/ml were significantly lower than those after treatment(46±11)pg/ml (P<0.01), and control group(45±8)pg/ml(P<0.05), and there after treatment in chronic cor pulmonale group, PaO2 were (6.3±2.0)kPa and (9.5±1.6)kPa respectively, the former was significantly lower than the latter(P<0.01). Conclusions This study suggests that hypoxia has a statistical relationship with the decrease of plasma CGRP and SP levels in patients with chronic cor pulmonale, particularly with CGRP, and the decrease of plasma CGRP and SP levels may contribute to the development of hypoxia pulmonary hypertension and play an important part in the pathophysiological changes of chronic cor pulmonale. Key words: Chronic cor pulmonale ; Calcitonin gene-related peptide ; Substance P ; Radioimmunoassay ;

Calcitonin gene-related peptide in human obesity

Objective To detect the plasma calcitonin gene-related peptide (CGRP) in children with enterovirus 71(EV71) infected hand foot and mouth disease(HFMD), and explore the relationship between CGRP and the severity of EV71 infected HFMD. Methods Two hundred children with EV71 infected HFMD in Xi′an Children′s Hospital from January 2017 to December 2017 were selected as the research group, and 50 healthy children were selected as control group in the same period.According to the severity of the disease, the research group was divided into the mild group (n=142) and the severe group (n=58). The level of plasma CGRP was detected by ELISA. Results In acute stage, the level of CGRP in children with EV71 infected HFMD was lower than that in control group, and the difference was statistically significant (t=4.235, P<0.001). The level of CGRP in acute stage in severe group[(29.90±5.10)pg/ml] was significantly lower than that of the mild group[(35.51±5.48)pg/ml], and the difference was statistically significant (t=6.615, P=0.001). The level of CGRP in mild group[(35.51±5.48)pg/ml] was slightly lower than that of the control group[(36.63±5.65)pg/ml], but the difference was insignificant (t=1.120, P=0.086). In recovery stage, the level of CGRP in the severe group was obviously higher than that in the acute stage(t=5.924, P=0.003). According to the ROC curve of CGRP in mild and severe EV71 infected HFMD, the critical value of CGRP in mild and severe HFMD was 28.12 pg/ml, and the sensitivity was 80.0% and the specificity was 50.0%. Conclusion The CGRP is associated with the progression of EV71 HFMD, and when CGRP is lower than 28.12 pg/ml, suggesting the possibility of severe HFMD.The decrease of plasma CGRP may be a risk factor for the progression of EV71 infected HFMD. Key words: Hand foot and mouth disease; Enterovirus 71; Calcitonin gene-related peptide

The aim of this study was to investigate the changes of calcitonin gene-related peptide (CGRP) plasma levels in patients with classical trigeminal neuralgia (TN) and if plasma CGRP concentrations could be used to predict the response to botulinum toxin type A (BTX-A). Forty-seven patients with classical TN were recruited and treated with BTX-A. A patient was considered a responder when the visual analog scale (VAS) score and number of episodes were reduced by at least 50% compared with baseline data. Matched healthy subjects with no headache history served as controls. CGRP levels were measured by the enzyme-linked immunosorbent assay. A total of 45 patients and 30 healthy controls completed the study. Plasma CGRP concentrations after treatment with BTX-A (median [interquartile range {IQR}] = 28.86 [14.75-61.23] pg/mL) were significantly lower than before treatment (median [IQR] = 55.38 [22.59-71.67] pg/mL, P < 0.001). Plasma CGRP concentrations in responders after treatment with BTX-A (median [IQR] = 28.02 [12.78-57.28] pg/mL) were significantly lower than before treatment (median [IQR] = 50.57 [24.30-70.09] pg/mL, P < 0.001). In nonresponders, there were no significant differences between the levels before and after treatment (P = 0.938). Age, gender, VAS score, taking/not taking carbamazepine, and the number of trigeminal nerve branches involved had no significant influence on the median difference between plasma CGRP concentrations. The concentration of CGRP before treatment was not predictive of the treatment result. CGRP levels decrease significantly in patients with classical TN after treatment with BTX-A. Plasma levels of CGRP cannot be used to predict the response to BTX-A. This study indicates that CGRP is likely to be involved in the pathophysiology of classical TN. Moreover, the analgesic mechanism of BTX-A may be related to the inhibition of CGRP release.