The effects of CGRP in vascular tissue - Classical vasodilation, shadowed effects and systemic dilemmas

Predictive Neuromarker Patterns for Calcification Metaplasia in Early Tendon Healing

Unsuccessful tendon healing leads to fibrosis and occasionally calcification. In these metaplastic drifts, the mouse AT preclinical injury model represents a robust experimental setting for studying tendon calcifications. Previously, calcium deposits were found in about 30% of tendons after 28 days post-injury. Although a neuromediated healing process has previously been documented, the expression patterns of NF200, NGF, NPY, GAL, and CGRP in mouse AT and their roles in metaplastic calcific repair remain to be explored. This study included a spatiotemporal analysis of these neuromarkers during the inflammatory phase (7 days p.i.) and the proliferative/early-remodelling phase (28 days p.i.). While the inflammatory phase is characterised by NF200 and CGRP upregulation, in the 28 days p.i., the non-calcified tendons (n = 16/24) showed overall NGF, NPY, GAL, and CGRP upregulation (compared to 7 days post-injury) and a return of NF200 expression to values similar to pre-injury. Presenting a different picture, in calcified tendons (n = 8), NF200 persisted at high levels, while NGF and NPY significantly increased, resulting in a higher NPY/CGRP ratio. Therefore, high levels of NF200 and imbalance between vasoconstrictive (NPY) and vasodilatory (CGRP) neuromarkers may be indicative of calcification. Tendon cells contributed to the synthesis of neuromarkers, suggesting that their neuro-autocrine/paracrine role is exerted by coordinating growth factors, cytokines, and neuropeptides. These findings offer insights into the neurobiological mechanisms of early tendon healing and identify new neuromarker profiles predictive of tendon healing outcomes.

Causality between migraine and cardiovascular disease: a bidirectional Mendelian randomization study

BACKGROUND

While growing evidence suggests a relationship between migraine and cardiovascular disease, the genetic evidence for a causal relationship between migraine and cardiovascular disease is still scarce. Investigating the causal association between migraine and cardiovascular disease is vital.

METHODS

We carried out a bidirectional Mendelian randomization (MR) study including discovery samples and replication samples using publicly available genome-wide association study (GWAS) summary datasets and stringent screening instrumental variables. Four different MR techniques-Inverse variance weighted (IVW), MR ‒Egger, weighted median, and weighted mode-as well as various sensitivity analyses-Cochran's Q, IVW radial, leave-one-out (LOO), and MR-PRESSO-were utilized to investigate the causal relationship between cardiovascular disease and migraine.

RESULTS

The protective causal effects of genetically predicted migraine on coronary artery disease (OR, 0.881; 95% CI 0.790-0.982; p = 0.023) and ischemic stroke (OR, 0.912; 95% CI 0.854-0.974; p = 0.006) were detected in forward MR analysis but not in any other cardiovascular disease. Consistently, we also discovered protective causal effects of coronary atherosclerosis (OR, 0.865; 95% CI 0.797-0.940; p = 0.001) and myocardial infarction (OR, 0.798; 95% CI 0.668-0.952; p = 0.012) on migraine in reverse MR analysis.

CONCLUSION

We found a potential protective effect of migraine on coronary artery disease and ischemic stroke and a potential protective effect of coronary atherosclerosis and myocardial infarction on migraine. We emphasised epidemiological and genetic differences and the need for long-term safety monitoring of migraine medications and future research to improve cardiovascular outcomes in migraine patients.

CGRP as a potential mediator for the sexually dimorphic responses to traumatic brain injury

BACKGROUND

The outcomes of traumatic brain injury (TBI) exhibit variance contingent upon biological sex. Although female sex hormones exert neuroprotective effects, the administration of estrogen and progesterone has not yielded conclusive results. Hence, it is conceivable that additional mediators, distinct from female sex hormones, merit consideration due to their potential differential impact on TBI outcomes. Calcitonin gene-related peptide (CGRP) exhibits sexually dimorphic expression and demonstrates neuroprotective effects in acute brain injuries. In this study, we aimed to examine sex-based variations in TBI structural and functional outcomes with respect to CGRP expression.

METHODS

Male and female Sprague Dawley rats were exposed to controlled cortical impact to induce severe TBI, followed by interventions with and without CGRP inhibition. In the acute phase of TBI, the study centered on elucidating the influence of CGRP on oxidative stress, nuclear factor erythroid 2-related factor 2 (Nrf2) and endothelial nitric oxide synthase (eNOS) signaling in the peri-impact tissue. Subsequently, during the chronic phase of TBI, the investigation expanded to evaluate CGRP expression in relation to lesion volume, microvascular dysfunction, and white matter injury, as well as working and spatial memory, anxiety-like, and depression-like behaviors in subjects of both sexes.

RESULTS

Female rats exhibited elevated levels of CGRP in the peri-impact brain tissue during both baseline conditions and in the acute and chronic phases of TBI, in comparison to age-matched male counterparts. Enhanced CGRP levels in specific brain sub-regions among female rats correlated with superior structural and functional outcomes following TBI compared to their male counterparts. CGRP inhibition induced heightened oxidative stress and a reduction in the expression of Nrf2 and eNOS in both male and female rats, with the observed alteration being more pronounced in females than in males.

CONCLUSIONS

This study marks the inaugural identification of CGRP as a downstream mediator contributing to the sexually dimorphic response observed in TBI outcomes.

Anti-calcitonin Gene-Related Peptide Monoclonal Antibodies in Migraine: Focus on Clinical Pharmacokinetics

The calcitonin gene-related peptide transmission was the target for recent development of drugs that effectively prevent attacks of both episodic and chronic migraine. The aim of this narrative review was to offer deeper insight into pharmacokinetics of monoclonal antibodies approved for prevention of migraine attacks. For this narrative review, relevant literature was searched for in MEDLINE and Google Scholar databases, covering periods 1966-2023 and 2006-2023, respectively. The ClinicalTrials.gov database was also searched for relevant clinical studies whose results had not been published previously in medical journals, covering the period 2000-2023. The monoclonal antibodies from this group are distributed mainly in the plasma and part of the extracellular space; they are neither metabolized in the liver nor excreted via the kidneys. The elimination of galcanezumab, eptinezumab and fremanezumab takes place only by a non-specific linear process via the reticuloendothelial system in the liver, while erenumab is eliminated by a non-specific process and by a specific, saturable process because of binding to receptors located on the cell membrane. Since the elimination processes do not have a large capacity, the half-life is about 2 weeks for erenumab and about 4 weeks for other monoclonal antibodies. Variability in the pharmacokinetics of these monoclonal antibodies is small in different subpopulations, and body weight is the only parameter to consider when choosing the dose of these drugs.

Evaluation of the risk of hypertension in patients treated with anti-CGRP monoclonal antibodies in a real-life study

OBJECTIVE

To explore the rate of hypertension incoming in patients treated with monoclonal antibodies against the calcitonin gene-related peptide.

BACKGROUND

The monoclonal antibodies blocking the calcitonin gene-related peptide are unquestionable effective in the prevention of migraine. Despite this, the development of hypertension has been detected in some patients.

METHODS

This was a retrospective study conducted at the University Hospital of Modena. Patients were visited quarterly up to 1 year.

RESULTS

Globally, no significant increase in the blood pressure was detected. The 5.7% of the patients developed a significant increase in their blood pressure. In particular, patients with a pre-existing hypertension were more likely to have a significant increase in the blood pressure.

CONCLUSION

The risk of developing hypertension during a treatment with anti-calcitonin gene-related peptide monoclonal antibodies seems low. Anyway, patients with a pre-existing hypertension should be cautiously monitored because they are more likely to develop hypertension.

CGRP attenuates pulmonary vascular remodeling by inhibiting the cGAS-STING-NFκB pathway in pulmonary arterial hypertension

BACKGROUND

Hyperproliferation, inflammation, and mitochondrial abnormalities in pulmonary artery smooth muscle cells (PASMCs) underlie the pathological mechanisms of vascular remodeling in pulmonary arterial hypertension (PAH). Cytoplasmic mtDNA activates the cGAS-STING-NFκB pathway and secretes pro-inflammatory cytokines that may be involved in the pathogenesis of PAH. Calcitonin gene-related peptide (CGRP) acts as a vasodilator to regulate patterns of cellular energy metabolism and has vasodilatory and anti-inflammatory effects.

METHODS

The role of the cGAS-STING-NFκB signaling pathway in PAH vascular remodeling and the regulation of CGRP in the cGAS-STING-NFκB signaling pathway were investigated by echocardiography, morphology, histology, enzyme immunoassay, and fluorometry.

RESULTS

Monocrotaline (MCT) could promote right heart hypertrophy, pulmonary artery intima thickening, and inflammatory cell infiltration in rats. Cinnamaldehyde (CA)-induced CGRP release alleviates MCT-induced vascular remodeling in PAH. CGRP reduces PDGF-BB-induced proliferation, and migration, and downregulates smooth muscle cell phenotypic proteins. In vivo and in vitro experiments confirm that the mitochondria of PASMCs were damaged during PAH, and the superoxide and mtDNA produced by injured mitochondria activate the cGAS-STING-NFκB pathway to promote PAH process, while CGRP could play an anti-PAH role by protecting the mitochondria and inhibiting the cGAS-STING-NFκB pathway through PKA.

CONCLUSION

This study identifies that CGRP attenuates cGAS-STING-NFκB axis-mediated vascular remodeling in PAH through PKA.

Blood pressure elevation in erenumab-treated patients with migraine: A retrospective real-world experience

BACKGROUND

Erenumab is a monoclonal antibody that targets the calcitonin gene-related peptide (CGRP) receptor and is approved for the preventative treatment of migraine in adults. CGRP is involved in the regulation of vasomotor tone under physiologic and pathologic conditions, including hypertension. While there has not been evidence of hypertension in preclinical models or clinical trials, post-marketing data suggest erenumab may be associated with hypertension. This led to a warning in the United States Food and Drug Administration prescribing information for erenumab.

OBJECTIVE

To determine the frequency of worsening blood pressure (BP) after initiation of erenumab in patients with migraine and how this is associated with hypertension.

METHODS

This is an observational retrospective cohort study evaluating patients at a tertiary headache or neurology department. Systolic and diastolic BPs were compared between the initial visit prior to initiation of erenumab, and follow-up visit while on erenumab. Worsening BP was defined as moving from a lower stage to a higher stage of BP, as defined by the American Heart Association. Serious adverse vascular events were also recorded.

RESULTS

A total of 335 patients were included in the final analysis (mean [SD] age of 45.7 [14.40] years, 83.9% [281/335] female). At baseline, 20.9% (70/335) of patients had a prior diagnosis of hypertension. The median (interquartile range) time to follow-up appointment from initial appointment was 20.5 (13.3-35.3) weeks. The mean (SD) BP at baseline was systolic 124.7 (15) mmHg and diastolic 77 (11) mmHg, and at follow-up was systolic 124.0 (15) mmHg and diastolic 77.8 (9) mmHg. Overall, 23.3% (78/335) of all patients had worsening BP, whereas 13/225 (3.9%) patients had improvement in their BP. Patients with atrial fibrillation were more likely to develop worsening BP (odds ratio, 4.9, 95% confidence interval 1.12-21.4; p = 0.035). There was no association between worsening BP and pre-existing hypertension, sex, body mass index, or age. One patient had non-ST elevation myocardial infarction attributed to a hypertensive emergency while on erenumab.

CONCLUSION

We found that 23.3% of patients initiated on erenumab may have developed worsening BP, suggesting the need for BP monitoring in patients initiated on erenumab.

Distribution and morphology of calcitonin gene-related peptide (CGRP) innervation in flat mounts of whole rat atria and ventricles

Calcitonin gene-related peptide (CGRP) is widely used as a marker for nociceptive afferent axons. However, the distribution of CGRP-IR axons has not been fully determined in the whole rat heart. Immunohistochemically labeled flat-mounts of the right and left atria and ventricles, and the interventricular septum (IVS) in rats for CGRP were assessed with a Zeiss imager to generate complete montages of the entire atria, ventricles, and septum, and a confocal microscope was used to acquire detailed images of selected regions. We found that 1) CGRP-IR axons extensively innervated all regions of the atrial walls including the sinoatrial node region, auricles, atrioventricular node region, superior/inferior vena cava, left pre-caval vein, and pulmonary veins. 2) CGRP-IR axons formed varicose terminals around individual neurons in some cardiac ganglia but passed through other ganglia without making appositions with cardiac neurons. 3) Varicose CGRP-IR axons innervated the walls of blood vessels. 4) CGRP-IR axons extensively innervated the right/left ventricular walls and IVS. Our data shows the rather ubiquitous distribution of CGRP-IR axons in the whole rat heart at single-cell/axon/varicosity resolution for the first time. This study lays the foundation for future studies to quantify the differences in CGRP-IR axon innervation between sexes, disease models, and species.

A ginger extract improves ocular blood flow in rats with endothelin-induced retinal blood flow dysfunction

The aim of this study was to investigate the effect of a ginger extract on optic nerve head blood flow (ONH BF) under endothelin-1 (ET-1) stimulation. Using laser speckle flowgraphy, we measured ONH BF in brown Norway rats. To establish the ONH BF impairment profile under ET-1 stimulation, we administered an intravitreal injection of ET-1 under anesthesia. We then gave the ginger extract sublingually to assess its effect on ONH BF in both normal and ET-1-induced ischemic conditions. Post ET-1 injection, there were no significant changes in parameters including intraocular pressure or systemic factors. ONH BF showed a dose-dependent decline after ET-1 injection, with a significant reduction after a 2.50 pmol ET-1 dose. Sublingual administration of the ginger extract significantly improved ONH BF in both normal and ET-1-stimulated rats. This suggests that our newly developed supplement for improving ONH BF has a potential role in retinal ischemic diseases, including glaucoma.

Heterogeneous vasomotor responses in segments from Göttingen Minipigs coronary, cerebral, and mesenteric artery: A comparative study

Göttingen Minipigs (GM) are used as an important preclinical model for cardiovascular safety pharmacology and for evaluation of cardiovascular drug targets. To improve the translational value of the GM model, the current study represents a basic characterization of vascular responses to endothelial regulators and sympathetic, parasympathetic, and sensory neurotransmitters in different anatomical origins. The aim of the current comparative and descriptive study is to use myography to characterize the vasomotor responses of coronary artery isolated from GM and compare the responses to those obtained from parallel studies using cerebral and mesenteric arteries. The selected agonists for sympathetic (norepinephrine), parasympathetic (carbachol), sensory (calcitonin gene-related peptide, CGRP), and endothelial pathways (endothelin-1, ET-1, and bradykinin) were used for comparison. Further, the robust nature of the vasomotor responses was evaluated after 24 h of cold storage of vascular tissue mimicking the situation under which human biopsies are often kept before experiments or grafting is feasible. Results show that bradykinin and CGRP consistently dilated, and endothelin consistently contracted artery segments from coronary, cerebral, and mesenteric origin. By comparison, norepinephrine and carbachol, had responses that varied with the anatomical source of the tissues. To support the basic characterization of GM vasomotor responses, we demonstrated the presence of mRNA encoding selected vascular receptors (CGRP- and ETA-receptors) in fresh artery segments. In conclusion, the vasomotor responses of isolated coronary, cerebral, and mesenteric arteries to selected agonists of endothelial, sympathetic, parasympathetic, and sensory pathways are different and the phenotypes are similar to sporadic human findings.

Ubrogepant and rimegepant: signal detection using spontaneous reports of adverse events from the Food and Drug Administration Adverse Event Reporting System

BACKGROUND

In this study, we fill this gap in knowledge by updating the safety profile of ubrogepant and rimegepant via disproportionality analysis in the Food and Drug Administration (FDA) Adverse Event Reporting System (FAERS), a US-based database registering spontaneous reports.

RESEARCH DESIGN AND METHODS

ASCII files of quarterly extraction of FAERS data were downloaded from the FDA website up to the 3rd quarter (Q3) of 2021 (last accessed 03/02/2022). Disproportionality analysis was done using the Reporting Odds Ratio (ROR) as a disproportionality measure. RORs of all AEs related to ubrogepant and rimegepant in FAERS were calculated in comparison with those related to erenumab. Drug-event pairs with a frequency ≤ 2, were removed according to European Medicine Agency (EMA)'s procedures.

RESULTS

In total, 2010 and 3691 individual case safety reports (ICSRs) recorded in FAERS reported ubrogepant and rimegepant, respectively, as suspect drugs. Ten disproportionality signals for ubrogepant and 25 disproportionality signals for rimegepant were identified; these were mostly related to psychiatric, neurological, gastrointestinal, skin, vascular, and infectious type of adverse events.

CONCLUSIONS

New safety aspects related to the treatment of ubrogepant and rimegepant using disproportionality analysis from spontaneous reporting databases were identified. Further studies are needed to confirm these findings.

Research Progress in Calcitonin Gene-Related Peptide and Bone Repair

Calcitonin gene-related peptide (CGRP) has 37 amino acids. Initially, CGRP had vasodilatory and nociceptive effects. As research progressed, evidence revealed that the peripheral nervous system is closely associated with bone metabolism, osteogenesis, and bone remodeling. Thus, CGRP is the bridge between the nervous system and the skeletal muscle system. CGRP can promote osteogenesis, inhibit bone resorption, promote vascular growth, and regulate the immune microenvironment. The G protein-coupled pathway is vital for its effects, while MAPK, Hippo, NF-κB, and other pathways have signal crosstalk, affecting cell proliferation and differentiation. The current review provides a detailed description of the bone repair effects of CGRP, subjected to several therapeutic studies, such as drug injection, gene editing, and novel bone repair materials.

CGRP physiology, pharmacology, and therapeutic targets: migraine and beyond

Calcitonin gene-related peptide (CGRP) is a neuropeptide with diverse physiological functions. Its two isoforms (α and β) are widely expressed throughout the body in sensory neurons as well as in other cell types, such as motor neurons and neuroendocrine cells. CGRP acts via at least two G protein-coupled receptors that form unusual complexes with receptor activity-modifying proteins. These are the CGRP receptor and the AMY1 receptor; in rodents, additional receptors come into play. Although CGRP is known to produce many effects, the precise molecular identity of the receptor(s) that mediates CGRP effects is seldom clear. Despite the many enigmas still in CGRP biology, therapeutics that target the CGRP axis to treat or prevent migraine are a bench-to-bedside success story. This review provides a contextual background on the regulation and sites of CGRP expression and CGRP receptor pharmacology. The physiological actions of CGRP in the nervous system are discussed, along with updates on CGRP actions in the cardiovascular, pulmonary, gastrointestinal, immune, hematopoietic, and reproductive systems and metabolic effects of CGRP in muscle and adipose tissues. We cover how CGRP in these systems is associated with disease states, most notably migraine. In this context, we discuss how CGRP actions in both the peripheral and central nervous systems provide a basis for therapeutic targeting of CGRP in migraine. Finally, we highlight potentially fertile ground for the development of additional therapeutics and combinatorial strategies that could be designed to modulate CGRP signaling for migraine and other diseases.

Macrophages and glial cells: Innate immune drivers of inflammatory arthritic pain perception from peripheral joints to the central nervous system

Millions of people suffer from arthritis worldwide, consistently struggling with daily activities due to debilitating pain evoked by this disease. Perhaps the most intensively investigated type of inflammatory arthritis is rheumatoid arthritis (RA), where, despite considerable advances in research and clinical management, gaps regarding the neuroimmune interactions that guide inflammation and chronic pain in this disease remain to be clarified. The pain and inflammation associated with arthritis are not isolated to the joints, and inflammatory mechanisms induced by different immune and glial cells in other tissues may affect the development of chronic pain that results from the disease. This review aims to provide an overview of the state-of-the-art research on the roles that innate immune, and glial cells play in the onset and maintenance of arthritis-associated pain, reviewing nociceptive pathways from the joint through the dorsal root ganglion, spinal circuits, and different structures in the brain. We will focus on the cellular mechanisms related to neuroinflammation and pain, and treatments targeting these mechanisms from the periphery and the CNS. A comprehensive understanding of the role these cells play in peripheral inflammation and initiation of pain and the central pathways in the spinal cord and brain will facilitate identifying new targets and pathways to aide in developing therapeutic strategies to treat joint pain associated with RA.

Calcitonin gene-related peptide predicts therapeutic response to midodrine hydrochloride in children with vasovagal syncope

The vasoconstriction agent midodrine hydrochloride is a vital treatment for pediatric patients diagnosed with vasovagal syncope (VVS), although the efficacy is variable. This study was designed to explore the value of calcitonin gene-related peptide (CGRP) in predicting the effect of midodrine hydrochloride treatment upon VVS patients. In total, 55 children diagnosed with VVS were treated with midodrine hydrochloride for 3 months. Therapeutic response was evaluated using a symptom score system. CGRP levels were significantly higher in VVS patients (68.700 ± 6.460) than in control subjects (43.400 ± 5.810; t = 18.207, P < 0.001) and symptom scores correlated positively with CGRP concentrations (r = 0.779, P < 0.001). Patients treated with midodrine hydrochloride showed a significant reduction in symptom scores [4 (0, 6.5) vs. 1 (1, 2); z = -6.481; P < 0.001]. However, the value of plasma CGRP were potently elevated in the positive-response subjects than in the negative-response subjects (70.080 ± 5.040) vs. (61.150 ± 3.090); t = 5.817; P < 0.001). The area under the ROC curve showed that the value of CGRP for predicting the therapeutic response to midodrine hydrochloride was 0.946 (95% CI: 0.879-0.997, P < 0.001). With high sensitivity (97.7%) and specificity (83.3%), CGRP predicted the therapeutic response to midodrine hydrochloride (cut-off value, 62.56 pg/ml). In conclusion, CGRP can be used to predict the effect of midodrine hydrochloride administration in VVS patients.

Myocardial perfusion recovery induced by an α-calcitonin gene-related peptide analogue

BACKGROUND

Endogenous calcitonin gene-related peptide (CGRP) induces cardioprotective effects through coronary vasodilation. However, the systemic administration of CGRP induces peripheral vasodilation and positive chronotropic and inotropic effects. This study aims to examine the net effect on coronary perfusion of the systemically administered α-calcitonin gene-related peptide analogue, SAX, in rats during myocardial infarction.

METHODS

Forty Sprague-Dawley rats underwent myocardial infarction. Following left anterior descending artery occlusion, [99mTc]Tc-sestamibi was administered to determine the myocardial perfusion before treatment. Twenty minutes, 24 and 48 h after [99mTc]Tc-sestamibi injection, the rats were treated with either SAX or placebo. Final infarct size was determined three weeks later by [99mTc]Tc-sestamibi SPECT/CT scan.

RESULTS

Thirty-one rats survived the surgery and 20 completed the follow-up SPECT/CT scan (SAX n = 12; Placebo n = 8). At baseline, there was no difference in size of perfusion defect between the groups (P = .88), but at follow-up the SAX group had improved myocardial recovery compared to the placebo group (P = .04), corresponding to a relative perfusion recovery of 55% in SAX-treated rats.

CONCLUSION

The CGRP analogue, SAX, has a cardioprotective effect in this rat model of myocardial infarction, improving myocardial perfusion recovery after chronic occlusion of the coronary artery.

CGRP Plasma Levels Correlate with the Clinical Evolution and Prognosis of Hospitalized Acute COVID-19 Patients

SARS-CoV-2 is the etiological agent of COVID-19, an extremely heterogenous disease that can cause severe respiratory failure and critical illness. To date, reliable biomarkers allowing for early patient stratification according to disease severity are still lacking. Calcitonin gene-related peptide (CGRP) is a vasoactive neuropeptide involved in lung pathophysiology and immune modulation and is poorly investigated in the COVID-19 context. In this observational, prospective cohort study, we investigated the correlation between CGRP and clinical disease evolution in hospitalized moderate to severe COVID-19 patients. Between January and May 2021 (Italian third pandemic wave), 135 consecutive SARS-CoV-2 patients were diagnosed as being eligible for the study. Plasma CGRP level evaluation and routine laboratory tests were performed on blood samples collected at baseline and after 7 days of hospitalization. At baseline, the majority our patients had a moderate to severe clinical presentation, and higher plasma CGRP levels predicted a higher risk of in-hospital negative evolution (odds-ratio OR 2.84 [IQR 1.07-7.51]) and were correlated with pulmonary intravascular coagulopathy (OR 2.92 [IQR 1.19-7.17]). Finally, plasma CGRP levels were also correlated with plasma IP10 levels. Our data support a possible crosstalk between the lung and the neuroimmune axis, highlighting a crucial role for plasma CGRP in sustaining COVID-19-related hyperinflammation.

The Responses to CGRP in the Territory of the Posterior Cerebral Artery in Migraine

Calcitonin gene-related peptide (CGRP) is important in trigeminovascular (TMV) sensitization with neurogenic inflammation which might be involved in CGRP-induced headache (CGRP-IH). Distribution of white matter lesions, migraine aura, and functional neuroimaging indicate that posterior circulation is especially exposed to TMV sensitization. The transcranial Doppler (TCD) is able to detect changes in the posterior cerebral artery (PCA) during CGRP stimulation. Thus, we studied CGRP-induced hemodynamic changes in PCA and frequency of CGRP-IH. Twenty healthy subjects and 20 patients with migraine participated in our study. TCD was used to monitor mean arterial velocity in posterior cerebral artery (vmPCA). Simultaneously, end-tidal carbon dioxide (Et-CO2), mean arterial pressure (MAP), and heart rate (HR) were measured. During the experiment, we monitored the frequency of CGRP-IH. We determined the values of vmPCA, Et-CO2, MAP, and HR and calculate the response of vmPCA, Et-CO2, MAP, and HR to CGRP. To test the differences and relationships, statistical methods were applied using SSPS. We found significant decrease in vmPCA in migraine and control groups and found the vmPCA response to be significantly lower in migraine (p = 0.018). Et-CO2 decreases in both groups, and it is significantly lower in migraine (p < 0.001). MAP is significantly higher in migraine (p = 0.001), while HR is not significantly higher in migraine (p = 0.570). CGRP-IH is significantly associated with vmPCA responses (p = 0.003) and migraine (p < 0.001). We concluded that hemodynamic changes in PCA are significantly related to CGRP-IH. The TMV sensitization might be pronounced in posterior circulation explaining clinical and morphologic issues in migraine.

Lipidated Calcitonin Gene-Related Peptide (CGRP) Peptide Antagonists Retain CGRP Receptor Activity and Attenuate CGRP Action In Vivo

Signaling through calcitonin gene-related peptide (CGRP) receptors is associated with pain, migraine, and energy expenditure. Small molecule and monoclonal antibody CGRP receptor antagonists that block endogenous CGRP action are in clinical use as anti-migraine therapies. By comparison, the potential utility of peptide antagonists has received less attention due to suboptimal pharmacokinetic properties. Lipidation is an established strategy to increase peptide half-life in vivo. This study aimed to explore the feasibility of developing lipidated CGRP peptide antagonists that retain receptor antagonist activity in vitro and attenuate endogenous CGRP action in vivo. CGRP peptide analogues based on the archetypal CGRP receptor antagonist, CGRP_8-37, were palmitoylated at the N-terminus, position 24, and near the C-terminus at position 35. The antagonist activities of the lipidated peptide analogues were tested in vitro using transfected Cos-7 cells expressing either the human or mouse CGRP receptor, amylin subtype 1 (AMY₁) receptor, adrenomedullin (AM) receptors, or calcitonin receptor. Antagonist activities were also evaluated in SK-N-MC cells that endogenously express the human CGRP receptor. Lipidated peptides were then tested for their ability to antagonize endogenous CGRP action in vivo using a capsaicin-induced dermal vasodilation (CIDV) model in C57/BL6J mice. All lipidated peptides except for the C-terminally modified analogue retained potent antagonist activity compared to CGRP_8-37 towards the CGRP receptor. The lipidated peptides also retained, and sometimes gained, antagonist activities at AMY₁, AM₁ and AM₂ receptors. Several lipidated peptides produced robust inhibition of CIDV in mice. This study demonstrates that selected lipidated peptide antagonists based on αCGRP_8-37 retain potent antagonist activity at the CGRP receptor and are capable of inhibition of endogenous CGRP action in vivo. These findings suggest that lipidation can be applied to peptide antagonists, such as αCGRP_8-37 and are a potential strategy for antagonizing CGRP action.

Intensity of perioperative analgesia but not pre-treatment pain is predictive of survival in dogs undergoing amputation plus chemotherapy for extremity osteosarcoma

The purpose of this bi‐institutional retrospective study was to determine whether, in dogs treated with limb amputation and adjunctive chemotherapy for osteosarcoma, oncologic outcomes are impacted by either: (1) baseline cancer pain severity, or (2) the approaches used for perioperative pain management. Data were extracted from the medical records of 284 dogs that underwent both limb amputation and chemotherapy (carboplatin and/or doxorubicin) between 1997 and 2017 for localized (non‐metastatic) osteosarcoma of the appendicular skeleton. Kaplan–Meier survival curves and Cox proportional hazard (PH) models were used to determine the impact that retrospectively scored baseline pain levels (high vs. low) and various analgesic and local anaesthetic treatments had on both metastasis‐free survival and all‐cause mortality. For the entire population, the median disease free interval and median overall survival times were 253 and 284 days, respectively. Baseline pain was rated as “low” in 84 dogs, and “high” in 190 dogs; pain severity had no detectable effect on either metastasis‐free survival or all‐cause mortality. When accounting for the potential influences of known prognostic factors, dogs treated with what was characterized as a high‐intensity perioperative analgesic plan (including both a non‐steroidal anti‐inflammatory drug [NSAID] and a bupivacaine‐eluting soaker catheter placed at the amputation site) had a higher probability of survival than dogs treated with a low‐intensity perioperative analgesic plan (neither an NSAID, nor a soaker catheter); the median overall survival times were 252 and 378 days, respectively (hazard ratio: 2.922; p = .020).

Intermedin Reduces Oxidative Stress and Apoptosis in Ventilator-Induced Lung Injury via JAK2/STAT3

Mechanical ventilation is an effective treatment for acute respiratory distress syndrome (ARDS), which can improve the prognosis of ARDS to a certain extent. However, it may further aggravate lung tissue injury, which is defined as ventilator-induced lung injury (VILI). Intermedin (IMD) belongs to the calcitonin gene-related peptide (CPRP) superfamily. Our previous studies have found that IMD reduces the expression proinflammatory cytokines, down-regulates nuclear translocation and improves the integrity of endothelial barrier in ARDS. However, the effect of IMD on VILI has not been clarified. Oxidative stress imbalance and apoptosis are the main pathophysiological characteristics of VILI. In the current study, we used C57B6/J mice and human pulmonary microvascular endothelial cells (HPMECs) to establish a VILI model to analyze the effects of IMD on VILI and explore its potential mechanism. We found that IMD alleviated lung injury and inflammatory response in VILI, mainly in reducing ROS levels, upregulating SOD content, downregulating MDA content, reducing the expression of Bax and caspase-3, and increasing the expression of Bcl-2. In addition, we also found that IMD played its anti-oxidative stress and anti-apoptotic effects via JAK2/STAT3 signaling. Our study may provide some help for the prevention and treatment of VILI.

Study on the Chemical Constituents and Anti-Migraine Activity of Supercritical CO2 Extracts of Zanthoxylum schinifolium

Background:Zanthoxylum schinifolium is a common herbal medicine in Southwest China. It is also a condiment commonly used in many families. In Chinese folk medicine, Z. schinifolium is considered to have the effect of relieving migraine, but there is no modern evidence on its anti-migraine mechanism.

Objective: The aim of this study was to investigate the chemical constituents of the supercritical carbon dioxide extracts of Z. schinifolium (CO₂-ZSE) and its effects on migraine animals.

Materials and Methods: Supercritical CO₂ extraction technology was applied to extract the dried fruit of Z. schinifolium, and the chemical components were determined by gas chromatography–mass spectrometry (GC-MS). Two migraine animal models were established by subcutaneous injection of nitroglycerin (NTG) and reserpine, respectively, to further evaluate the therapeutic effect of CO₂-ZSE and explore its mechanism. On the basis of the experimental results, the therapeutic effects of linalool in different dosages and different ways of administration on NTG-induced migraine rats have been further investigated.

Results: About 125 peaks were detected in CO₂-ZSE, and the relative content of linalool was 74.16%. CO₂-ZSE decreased the number of head-scratching significantly and the levels of serum nitric oxide (NO), endothelin-1 (ET-1), calcitonin gene–related peptide (CGRP), interleukin-1β (IL-1β), nuclear factor kappa B (NF-κB) p65, and inhibitor of kappa B alpha (IκBα), and increased the level of 5-hydroxytryptamine (5-HT). Linalool has the potential to reduce the frequency of scratching the head and the expressions of NO, ET-1, and CGRP in NTG-induced migraine rats.

Conclusion: CO₂-ZSE has a definite therapeutic effect on migraine by affecting the expression of vasomotor factors and the inflammatory pathway. Linalool has been proven to be the main effective substance against migraine. These findings provide scientific basis for the development of effective and simple migraine therapy.

The Local Neuropeptide System of Keratinocytes

Neuropeptides have been known for over 50 years as chemical signals in the brain. However, it is now well established that the synthesis of this class of peptides is not restricted to neurons. For example, human skin not only expresses several functional receptors for neuropeptides but, also, can serve as a local source of neuroactive molecules such as corticotropin-releasing hormone, melanocortins, and β-endorphin. In contrast, an equivalent of the hypothalamic-pituitary axis in the oral mucosa has not been well characterized to date. In view of the differences in the morphology and function of oral mucosal and skin cells, in this review I surveyed the existing evidence for a local synthesis of hypothalamic-pituitary, opiate, neurohypophyseal, and neuroendocrine neuropeptides in both epidermal and oral keratinocytes.

DNA Methylation Pattern of CALCA and CALCB in Extremely Premature Infants with Monochorionic Triplets after Single-Embryo Transfer

Compared with full-term peers, premature infants are more likely to suffer from neonatal diseases and death. Variations in DNA methylation may affect these pathological processes. Calcitonin gene-related peptide (CGRP) plays a complex and diversified role in reproduction and chronic inflammation, and participates in the functional maintenance of vascular adaptation and trophoblast cells during pregnancy. Here, premature live births with single-chorionic triple embryos after single-embryo transfer were used as research objects, while full-term infants with double embryos and double-chorionic twins were used as controls. DNA was extracted from umbilical cord tissues for pyrosequencing to detect the methylation level of CpG island in CGRP promoter region. The average values of CGRP methylation in the umbilical cord tissues of very premature fetuses were higher than that of normal controls obtained from the databases. Immunofluorescence results showed that the expression of αCGRP was decreased in the blood vessel wall of the umbilical cord of monozygotic triplets, especially in death cases, while the βCGRP had a compensatory expression. In conclusion, our findings suggest that hypermethylation of CGRP might be considered as an important cause of serious neonatal morbidities.

Inflammatory complications of CGRP monoclonal antibodies: a case series

BACKGROUND

Calcitonin gene-related peptide (CGRP) is expressed throughout the body and is a known mediator of migraine, exerting this biological effect through activation of trigeminovascular, meningeal and associated neuronal pathways located in close proximity to the central nervous system. Monoclonal antibodies (mAb) targeting the CGRP pathway are an effective new preventive treatment for migraine, with a generally favourable adverse event profile. Pre-clinical evidence supports an anti-inflammatory/immunoregulatory role for CGRP in other organ systems, and therefore inhibition of the normal action of this peptide may promote a pro-inflammatory response.

CASES

We present a case series of eight patients with new or significantly worsened inflammatory pathology in close temporal association with the commencement of CGRP mAb therapy.

CONCLUSION

This case series provides novel insights on the potential molecular mechanisms and side-effects of CGRP antagonism in migraine and supports clinical vigilance in patient care going forward.

The Influence of Calcitonin Gene-Related Peptide on Cerebral Hemodynamics in Nonmigraine Subjects with Calcitonin Gene-Related Peptide-Induced Headaches

Background

Calcitonin gene-related peptide (CGRP) is regarded as an important molecule in trigeminovascular sensitization (TVS). CGRP-induced headaches (CGRP-IH) are evoked by intravascular administration of CGRP in nonmigraine and migraine subjects. CGRP might be associated with vasodilatation of the middle cerebral artery (MCA). It is unclear whether CGRP-induced hemodynamic changes relate to CGRP-IH in nonmigraine subjects.

Methods

Twenty healthy subjects participated in our study. Polymodal recording of mean arterial velocity in MCA (vm MCA), end-tidal carbon dioxide partial pressure (Et-CO₂), mean arterial pressure (MAP), and heart rate (HR) was employed using transcranial Doppler (TCD) sonography. During the experiment, we administered intravenous infusion of CGRP at a rate of 1.5 mcg/min. The vm MCA, Et-CO₂, HR, and MAP were determined at time points T₀, T₁, T₂, and T₃. We calculated the responses at different time points and combined them into a single response vm MCA_tot, Et-CO_2tot, HR_tot, and MAP_tot.

Results

We found significant differences along the time points in vm MCA (p = <0.001), Et-CO₂ (p = 0.003), MAP (p < 0.001), and HR (p < 0.001). The relationship between vm MCA_tot and Et-CO_2tot was significant and positive (p = 0.005). The t-test showed significant differences between CGRP-IH and non-CGRP-IH subjects in vm MCA_tot (p = 0.021) but not in Et-CO_2tot (p = 0.838), MAP_tot (p = 0.839), and HR_tot (p = 0.198). Only vm MCA_tot showed a significant relationship with CGRP-IH (p = 0.028).

Conclusions

Our study provides evidence for vasodilatation of MCA in relation to CGRP-IH due to intravascular CGRP detected by multimodal TCD. In the context of TVS induced by CGRP, MCA vasodilatation seems to represent an epiphenomenon of the underlying TVS.