Environmental enrichment alleviates hyperalgesia by modulating central sensitization in a nitroglycerin-induced chronic migraine model of mice.

BACKGROUND: Chronic migraine (CM) is a debilitating neurofunctional disorder primarily affecting females, characterized by central sensitization. Central sensitization refers to the enhanced response to sensory stimulation, which involves changes in neuronal excitability, synaptic plasticity, and neurotransmitter release. Environmental enrichment (EE) can increase the movement, exploration, socialization and other behaviors of mice. EE has shown promising effects in various neurological disorders, but its impact on CM and the underlying mechanism remains poorly understood. Therefore, the purpose of this study was to determine whether EE has the potential to serve as a cost-effective intervention strategy for CM. METHODS: A mouse CM model was successfully established by repeated administration of nitroglycerin (NTG). We selected adult female mice around 8 weeks old, exposed them to EE for 2 months, and then induced the CM model. Nociceptive threshold tests were measured using Von Frey filaments and a hot plate. The expression of c-Fos, calcitonin gene-related peptide (CGRP) and inflammatory response were measured using WB and immunofluorescence to evaluate central sensitization. RNA sequencing was used to find differentially expressed genes and signaling pathways. Finally, the expression of the target differential gene was investigated. RESULTS: Repeated administration of NTG can induce hyperalgesia in female mice and increase the expression of c-Fos and CGRP in the trigeminal nucleus caudalis (TNC). Early exposure of mice to EE reduced NTG-induced hyperalgesia in CM mice. WB and immunofluorescence revealed that EE inhibited the overexpression of c-Fos and CGRP in the TNC of CM mice and alleviated the inflammatory response of microglia activation. RNA sequencing analysis identified that several central sensitization-related signaling pathways were altered by EE. VGluT1, a key gene involved in behavior, internal stimulus response, and ion channel activity, was found to be downregulated in mice exposed to EE. CONCLUSION: EE can significantly ameliorate hyperalgesia in the NTG-induced CM model. The mechanisms may be to modulate central sensitization by reducing the expression of CGRP, attenuating the inflammatory response, and downregulating the expression of VGluT1, etc., suggesting that EE can serve as an effective preventive strategy for CM.

Extrasynaptic δGABAA receptors mediate resistance to migraine-like phenotype in rats.

BACKGROUND: GABA, a key inhibitory neurotransmitter, has synaptic and extrasynaptic receptors on the postsynaptic neuron. Background GABA, which spills over from the synaptic cleft, acts on extrasynaptic delta subunit containing GABAA receptors. The role of extrasynaptic GABAergic input in migraine is unknown. We investigated the susceptibility to valid migraine-provoking substances with clinically relevant behavioral readouts in Genetic Absence Epilepsy of Rats Strasbourg (GAERS), in which the GABAergic tonus was altered. Subsequently, we screened relevant GABAergic mechanisms in Wistar rats by pharmacological means to identify the mechanisms. METHODS: Wistar and GAERS rats were administered nitroglycerin (10 mg/kg) or levcromakalim (1 mg/kg). Mechanical allodynia and photophobia were assessed using von Frey monofilaments and a dark-light box. Effects of GAT-1 blocker tiagabine (5 mg/kg), GABAB receptor agonist baclofen (2 mg/kg), synaptic GABAA receptor agonist diazepam (1 mg/kg), extrasynaptic GABAA receptor agonists gaboxadol (4 mg/kg), and muscimol (0.75 mg/kg), T-type calcium channel blocker ethosuximide (100 mg/kg) or synaptic GABAA receptor antagonist flumazenil (15 mg/kg) on levcromakalim-induced migraine phenotype were screened. RESULTS: Unlike Wistar rats, GAERS exhibited no reduction in mechanical pain thresholds or light aversion following nitroglycerin or levcromakalim injection. Ethosuximide did not reverse the resistant phenotype in GAERS, excluding the role of T-type calcium channel dysfunction in this phenomenon. Tiagabine prevented levcromakalim-induced mechanical allodynia in Wistar rats, suggesting a key role in enhanced GABA spillover. Baclofen did not alleviate mechanical allodynia. Diazepam failed to mitigate levcromakalim-induced migraine phenotype. Additionally, the resistant phenotype in GAERS was not affected by flumazenil. Extrasynaptic GABAA receptor agonists gaboxadol and muscimol inhibited periorbital allodynia in Wistar rats. CONCLUSION: Our study introduced a rat strain resistant to migraine-provoking agents and signified a critical involvement of extrasynaptic δGABAergic receptors. Extrasynaptic δ GABAA receptors, by mediating constant background inhibition on the excitability of neurons, stand as a novel drug target with a therapeutic potential in migraine.

Local carbachol application induces oral microvascular recruitment and improves gastric tissue oxygenation during hemorrhagic shock in dogs.

Introduction: Hemorrhagic shock is characterized by derangements of the gastrointestinal microcirculation. Topical therapy with nitroglycerine or iloprost improves gastric tissue oxygenation but not regional perfusion, probably due to precapillary adrenergic innervation. Therefore, this study was designed to investigate the local effect of the parasympathomimetic carbachol alone and in combination with either nitroglycerine or iloprost on gastric and oral microcirculation during hemorrhagic shock. Methods: In a cross-over design five female foxhounds were repeatedly randomized into six experimental groups. Carbachol, or carbachol in combination with either nitroglycerine or iloprost were applied topically to the oral and gastric mucosa. Saline, nitroglycerine, or iloprost application alone served as control groups. Then, a fixed-volume hemorrhage was induced by arterial blood withdrawal followed by blood retransfusion after 1h of shock. Gastric and oral microcirculation was determined using reflectance spectrophotometry and laser Doppler flowmetry. Oral microcirculation was visualized with videomicroscopy. Statistics: 2-way-ANOVA for repeated measurements and Bonferroni post-hoc analysis (mean ± SEM; p < 0.05). Results: The induction of hemorrhage led to a decrease of gastric and oral tissue oxygenation, that was ameliorated by local carbachol and nitroglycerine application at the gastric mucosa. The sole use of local iloprost did not improve gastric tissue oxygenation but could be supplemented by local carbachol treatment. Adding carbachol to nitroglycerine did not further increase gastric tissue oxygenation. Gastric microvascular blood flow remained unchanged in all experimental groups. Oral microvascular blood flow, microvascular flow index and total vessel density decreased during shock. Local carbachol supply improved oral vessel density during shock and oral microvascular flow index in the late course of hemorrhage. Conclusion: The specific effect of shifting the autonomous balance by local carbachol treatment on microcirculatory variables varies between parts of the gastrointestinal tract. Contrary to our expectations, the improvement of gastric tissue oxygenation by local carbachol or nitroglycerine application was not related to increased microvascular perfusion. When carbachol is used in combination with local vasodilators, the additional effect on gastric tissue oxygenation depends on the specific drug combination. Therefore, modulation of tissue oxygen consumption, mitochondrial function or alterations in regional blood flow distribution should be investigated.

Glycerol Trinitrate Acts Downstream of Calcitonin Gene-Related Peptide in Trigeminal Nociception-Evidence from Rodent Experiments with Anti-CGRP Antibody Fremanezumab.

Calcitonin gene-related peptide (CGRP) and nitric oxide (NO) have been recognized as important mediators in migraine but their mechanisms of action and interaction have not been fully elucidated. Monoclonal anti-CGRP antibodies like fremanezumab are successful preventives of frequent migraine and can be used to study CGRP actions in preclinical experiments. Fremanezumab (30 mg/kg) or an isotype control monoclonal antibody was subcutaneously injected to Wistar rats of both sexes. One to several days later, glyceroltrinitrate (GTN, 5 mg/kg) mimicking nitric oxide (NO) was intraperitoneally injected, either once or for three consecutive days. The trigeminal ganglia were removed to determine the concentration of CGRP using an enzyme-linked immunosorbent assay (ELISA). In one series of experiments, the animals were trained to reach an attractive sugar solution, the access to which could be limited by mechanical or thermal barriers. Using a semi-automated registration system, the frequency of approaches to the source, the residence time at the source, and the consumed solution were registered. The results were compared with previous data of rats not treated with GTN. The CGRP concentration in the trigeminal ganglia was generally higher in male rats and tended to be increased in animals treated once with GTN, whereas the CGRP concentration decreased after repetitive GTN treatment. No significant difference in CGRP concentration was observed between animals having received fremanezumab or the control antibody. Animals treated with GTN generally spent less time at the source and consumed less sugar solution. Without barriers, there was no significant difference between animals having received fremanezumab or the control antibody. Under mechanical barrier conditions, all behavioral parameters tended to be reduced but animals that had received fremanezumab tended to be more active, partly compensating for the depressive effect of GTN. In conclusion, GTN treatment seems to increase the production of CGRP in the trigeminal ganglion independently of the antibodies applied, but repetitive GTN administration may deplete CGRP stores. GTN treatment generally tends to suppress the animals' activity and increase facial sensitivity, which is partly compensated by fremanezumab through reduced CGRP signaling. If CGRP and NO signaling share the same pathway in sensitizing trigeminal afferents, GTN and NO may act downstream of CGRP to increase facial sensitivity.

Topical glyceryl trinitrate to increase radial artery diameter in neonates: study protocol for a randomized controlled trial.

BACKGROUND: Newborn infants admitted to the neonatal intensive care unit require arterial cannulation for hemodynamic monitoring and blood sampling. Arterial access is achieved through catheterization of umbilical or peripheral arteries. Peripheral artery cannulation is performed in critically ill newborns, but artery localization and cannulation is often challenging and unsuccessful. Therefore, increasing the internal diameter and preventing vasospasm are important for successful peripheral artery cannulation in neonates. Topical glyceryl trinitrate has the potential to increase cannulation success by relaxing arterial smooth muscles and thus increasing the internal diameter. We aim to conduct a pilot randomized controlled trial to evaluate the efficacy and safety of topycal glyceryl trinitrate in increasing the diameter of the radial artery in neonates. METHODS/DESIGN: This study will be a single-center, observer-blind, randomized, placebo-controlled trial conducted in the neonatal intensive care unit of Perth Children's Hospital, Western Australia. A total of 60 infants born at >34 weeks of gestation who are admitted for elective surgery or medical reasons and for whom a peripheral arterial line is needed for sampling or blood pressure monitoring will be recruited after informed parental consent is obtained. The primary outcome will be the change in radial arterial diameter from baseline to postintervention. Secondary outcomes will be the absolute and percentage change from baseline in the radial arterial diameter in both limbs and safety (hypotension and methemoglobinemia). DISCUSSION: This will be the first randomized controlled trial evaluating the use of topical glyceryl trinitrate to facilitate peripheral artery cannulation in neonates. If our pilot randomized controlled trial confirms the benefits of glyceryl trinitrate patches, it will pave the way for large multicenter randomized controlled trials in this field.

Comparison of the efficacy of nifedipine with ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor: a systematic review and meta-analysis.

BACKGROUND: Some studies have compared the efficacy of nifedipine with that of other tocolytic drugs in the treatment of preterm labor, but the reported results are conflicting. OBJECTIVE: To compare the efficacy of nifedipine with that of ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor. METHODS: In this systematic review and meta-analysis, PubMed/MEDLINE, Scopus, Clarivate Analytics Web of Science, and Google Scholar were searched until April 3,2024 using predefined keywords. Randomized controlled trials (RCTs) and clinical trials that compared the efficacy of nifedipine with that of ritodrine, nitroglycerine and magnesium sulfate for the management of preterm labor were included. Two authors independently reviewed the articles, assessed their quality and extracted the data. The quality of the included RCTs based on the Cochrane Risk of Bias Tool 1 for clinical trial studies. The risk difference (RD) with the associated 95% confidence interval (CI) was calculated. A forest plot diagram was used to show the comparative point estimates of nifedipine and other tocolytic drugs on the prevention of preterm labor and their associated 95% confidence intervals based on the duration of pregnancy prolongation. Study heterogeneity was evaluated by the I2 index, and publication bias was evaluated by Egger's test. RESULTS: Forty studies enrolling 4336 women were included. According to our meta-analysis, there was a significant difference in the prolongation of preterm labor within the first 48 h between the nifedipine group and the nitroglycerine group (RD, -0.04; 95% CI, -0.08 to -0.00; I2: 32.3%). Additionally, there were significant differences between nifedipine and ritodrine (RD, 0.11; 95% CI, 0.02 to 0.21; I2, 51.2%) for more than one week RD, 0.10; 95% CI, 0.03 to 0.19; I2, 33.2%) and for 34 weeks and more. The difference between nifedipine and magnesium sulfate was not significant in any of the four time points. CONCLUSIONS: Considering the superiority of nifedipine over ritodrine and nitroglycerine and its similar efficacy to magnesium sulfate for tocolysis, it seems that the side effects of these options determine the first drug line.

Differences in Neuropathology between Nitroglycerin-Induced Mouse Models of Episodic and Chronic Migraine.

Multiple animal models of migraine have been used to develop new therapies. Understanding the transition from episodic (EM) to chronic migraine (CM) is crucial. We established models mimicking EM and CM pain and assessed neuropathological differences. EM and CM models were induced with single NTG or multiple injections over 9 days. Mechanical hypersensitivity was assessed. Immunofluorescence utilized c-Fos, NeuN, and Iba1. Proinflammatory and anti-inflammatory markers were analyzed. Neuropeptides (CGRP, VIP, PACAP, and substance P) were assessed. Mechanical thresholds were similar. Notable neuropathological distinctions were observed in Sp5C and ACC. ACC showed increased c-Fos and NeuN expression in CM (p < 0.001) and unchanged in EM. Sp5C had higher c-Fos and NeuN expression in EM (p < 0.001). Iba1 was upregulated in Sp5C of EM and ACC of CM (p < 0.001). Proinflammatory markers were strongly expressed in Sp5C of EM and ACC of CM. CGRP expression was elevated in both regions and was higher in CM. VIP exhibited higher levels in the Sp5C of EM and ACC of CM, whereas PACAP and substance P were expressed in the Sp5C in both models. Despite similar thresholds, distinctive neuropathological differences in Sp5C and ACC between EM and CM models suggest a role in the EM to CM transformation.

Unveiling the therapeutic potential of Dl-3-n-butylphthalide in NTG-induced migraine mouse: activating the Nrf2 pathway to alleviate oxidative stress and neuroinflammation.

BACKGROUND: Migraine stands as a prevalent primary headache disorder, with prior research highlighting the significant involvement of oxidative stress and inflammatory pathways in its pathogenesis and chronicity. Existing evidence indicates the capacity of Dl-3-n-butylphthalide (NBP) to mitigate oxidative stress and inflammation, thereby conferring neuroprotective benefits in many central nervous system diseases. However, the specific therapeutic implications of NBP in the context of migraine remain to be elucidated. METHODS: We established a C57BL/6 mouse model of chronic migraine (CM) using recurrent intraperitoneal injections of nitroglycerin (NTG, 10 mg/kg), and prophylactic treatment was simulated by administering NBP (30 mg/kg, 60 mg/kg, 120 mg/kg) by gavage prior to each NTG injection. Mechanical threshold was assessed using von Frey fibers, and photophobia and anxious behaviours were assessed using a light/dark box and elevated plus maze. Expression of c-Fos, calcitonin gene-related peptide (CGRP), Nucleus factor erythroid 2-related factor 2 (Nrf2) and related pathway proteins in the spinal trigeminal nucleus caudalis (SP5C) were detected by Western blotting (WB) or immunofluorescence (IF). The expression of IL-1ß, IL-6, TNF-α, Superoxide dismutase (SOD) and malondialdehyde (MDA) in SP5C and CGRP in plasma were detected by ELISA. A reactive oxygen species (ROS) probe was used to detect the expression of ROS in the SP5C. RESULTS: At the end of the modelling period, chronic migraine mice showed significantly reduced mechanical nociceptive thresholds, as well as photophobic and anxious behaviours. Pretreatment with NBP attenuated nociceptive sensitization, photophobia, and anxiety in the model mice, reduced expression levels of c-Fos and CGRP in the SP5C and activated Nrf2 and its downstream proteins HO-1 and NQO-1. By measuring the associated cytokines, we also found that NBP reduced levels of oxidative stress and inflammation. Most importantly, the therapeutic effect of NBP was significantly reduced after the administration of ML385 to inhibit Nrf2. CONCLUSIONS: Our data suggest that NBP may alleviate migraine by activating the Nrf2 pathway to reduce oxidative stress and inflammation in migraine mouse models, confirming that it may be a potential drug for the treatment of migraine.

The crucial role of locus coeruleus noradrenergic neurons in the interaction between acute sleep disturbance and headache.

BACKGROUND: Both epidemiological and clinical studies have indicated that headache and sleep disturbances share a complex relationship. Although headache and sleep share common neurophysiological and anatomical foundations, the mechanism underlying their interaction remains poorly understood. The structures of the diencephalon and brainstem, particularly the locus coeruleus (LC), are the primary sites where the sleep and headache pathways intersect. To better understand the intricate nature of the relationship between headache and sleep, our study focused on investigating the role and function of noradrenergic neurons in the LC during acute headache and acute sleep disturbance. METHOD: To explore the relationship between acute headache and acute sleep disturbance, we primarily employed nitroglycerin (NTG)-induced migraine-like headache and acute sleep deprivation (ASD) models. Initially, we conducted experiments to confirm that ASD enhances headache and that acute headache can lead to acute sleep disturbance. Subsequently, we examined the separate roles of the LC in sleep and headache. We observed the effects of drug-induced activation and inhibition and chemogenetic manipulation of LC noradrenergic neurons on ASD-induced headache facilitation and acute headache-related sleep disturbance. This approach enabled us to demonstrate the bidirectional function of LC noradrenergic neurons. RESULTS: Our findings indicate that ASD facilitated the development of NTG-induced migraine-like headache, while acute headache affected sleep quality. Furthermore, activating the LC reduced the headache threshold and increased sleep latency, whereas inhibiting the LC had the opposite effect. Additional investigations demonstrated that activating LC noradrenergic neurons further intensified pain facilitation from ASD, while inhibiting these neurons reduced this pain facilitation. Moreover, activating LC noradrenergic neurons exacerbated the impact of acute headache on sleep quality, while inhibiting them alleviated this influence. CONCLUSION: The LC serves as a significant anatomical and functional region in the interaction between acute sleep disturbance and acute headache. The involvement of LC noradrenergic neurons is pivotal in facilitating headache triggered by ASD and influencing the effects of headache on sleep quality.

Inhaled Nitroglycerin for Pulmonary Edema in Air Medical Services: A Retrospective Pilot Study.

OBJECTIVE: The use of traditional inhaled pulmonary vasodilators, such as nitric oxide, to treat symptomatic pulmonary edema is not practical in the air medical or prehospital environment because of difficulty with administration. A hospital-based critical care air medical transport service initiated a pilot study to investigate the use of inhaled nitroglycerin (iNTG) as an alternative pulmonary vasodilator. METHODS: For this pilot study, iNTG was administered using a jet nebulizer setup and concentrated nitroglycerin, both of which are widely available in acute care settings. In conjunction with medical oversight, transport personnel identified patients with respiratory distress secondary to pulmonary edema. Twenty-two months after initiating the protocol, a retrospective chart review was conducted. Data for patients receiving iNTG were retrospectively abstracted through a medical record search and manual chart review. RESULTS: Twelve patients received iNTG during the pilot study. Basic demographics, medical comorbidities, concurrent medications, laboratory values, and radiographic studies were collected for each patient. Basic statistics were performed to identify any potential trends. CONCLUSION: The administration of iNTG is feasible in an air medical transport setting and may provide a useful adjunct to treating patients with pulmonary edema and respiratory distress. Because iNTG delivery targets the pulmonary vasculature, this may be of particular benefit in patients with a poor hemodynamic profile. Larger randomized controlled or cohort studies are needed to specifically analyze and compare hemodynamics, diagnostics, and patient outcomes.

AMPK activation attenuates central sensitization in a recurrent nitroglycerin-induced chronic migraine mouse model by promoting microglial M2-type polarization.

BACKGROUND: Energy metabolism disorders and neurogenic inflammation play important roles in the central sensitization to chronic migraine (CM). AMP-activated protein kinase (AMPK) is an intracellular energy sensor, and its activation regulates inflammation and reduces neuropathic pain. However, studies on the involvement of AMPK in the regulation of CM are currently lacking. Therefore, this study aimed to explore the mechanism underlying the involvement of AMPK in the central sensitization to CM. METHODS: Mice with recurrent nitroglycerin (NTG)-induced CM were used to detect the expression of AMPK protein in the trigeminal nucleus caudalis (TNC). Following intraperitoneal injection of the AMPK activator 5-aminoimidazole-4-carboxyamide ribonucleoside (AICAR) and inhibitor compound C, the mechanical pain threshold, activity level, and pain-like behaviors in the mice were measured. The expression of calcitonin gene-related peptide (CGRP) and cytokines, M1/M2 microglia, and NF-κB pathway activation were detected after the intervention. RESULTS: Repeated NTG injections resulted in a gradual decrease in AMPK protein expression, and the negative regulation of AMPK by increased ubiquitin-like plant homeodomain and RING finger domain 1 (UHRF1) expression may counteract AMPK activation by increasing ADP/ATP. AICAR can reduce the hyperalgesia and pain-like behaviors of CM mice, improve the activity of mice, reduce the expression of CGRP, IL-1ß, IL-6, and TNF-α in the TNC region, and increase the expression of IL-4 and IL-10. Moreover, AMPK in TNC was mainly located in microglia. AICAR could reduce the expression of inducible NO synthase (iNOS) in M1 microglia and increase the expression of Arginase 1 (Arg1) in M2 microglia by inhibiting the activation of NF-κB pathway. CONCLUSIONS: AMPK was involved in the central sensitization of CM, and the activation of AMPK reduced neuroinflammation in NTG-induced CM mice. AMPK may provide new insights into interventions for energy metabolism disorders and neurogenic inflammation in migraine.

Amelioration of nitroglycerin-induced migraine in mice via Wuzhuyu decoction: Inhibition of the MZF1/PGK1 pathway and activation of NRF2 antioxidant response.

ETHNOPHARMACOLOGICAL RELEVANCE: Migraine, a chronic and intricate disorder, manifests as recurrent episodic headaches accompanied by various neurological symptoms. Wuzhuyu Decoction (WZYD) is a traditional Chinese medical formula with promising effects in treating migraines; however, its underlying mechanisms have not yet been clarified. AIM OF STUDY: The study aimed to evaluate WZYD's effectiveness in migraine treatment and investigate the potential mechanism of WZYD's effects on migraine and oxidative stress. MATERIALS AND METHODS: Behavior tests and immunofluorescence assay for the intensity of migraine markers to assess the migraine-relieving effect of WZYD after chronic migraine model induced by nitroglycerin in mice. The impacts of WZYD on oxidative stress-related markers, including reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD), nuclear factor erythroid 2-related factor 2 (NRF2), heme oxygenase 1 (HO1), and NAD (P)H quinone oxidoreductase 1 (NQO1) in brain tissue were examined. In addition, protein expression or mRNA levels of the MZF1/PGK1 were detected using Western blot or PCR, respectively. Finally, the MZF1 overexpression vector was constructed to the higher level of MZF1. The MZF1/PGK1 signaling pathway expression was evaluated by markers of oxidative stress including NRF2 and others in this series of experiments. RESULTS: Through murine model experimentation, we observed that WZYD effectively alleviates migraine symptoms, signifying its therapeutic efficacy. Mechanistically, WZYD emerges as a potent activator of the NRF2, acting as a robust defense against oxidative stress. In vitro investigations demonstrated that WZYD combats oxidative stress and curbs cell apoptosis induced by these detrimental conditions. Furthermore, by suppressing the transcriptional expression of PGK1, an influential player in the NRF2 pathway, WZYD effectively activates NRF2 signaling. Intriguingly, we have identified MZF1 as the mediator orchestrating the regulation of the PGK1/NRF2 pathway by WZYD. CONCLUSION: The study confirms the effectiveness of WZYD in alleviating migraine symptoms. Mechanistically, WZYD activated the NRF2 signaling pathway; moreover, the action of WZYD involved the down-regulation of PGK1 mediated by MZF1, which promoted the activation of the NRF2 pathway. This study advances our understanding of the intricate mechanisms driving WZYD's efficacy, paving the way for novel treatments in migraine management.

Association of cumulative low-density lipoprotein cholesterol exposure with vascular function.

BACKGROUND: The relationship between cumulative low-density lipoprotein cholesterol (LDL-C) exposure and progression of atherosclerosis remains uncertain. OBJECTIVE: The aim of this study was to determine the relationship between cumulative LDL-C level and flow-mediated vasodilation (FMD), nitroglycerine-induced vasodilation (NID) and the presence of plaque in the common carotid artery (CCA). METHODS: This was a cross-sectional study. We measured FMD in 8208 subjects, NID in 1822 subjects, and CCA plaque in 591 subjects who were not taking lipid-lowering drugs. The subjects were divided into four groups based on cumulative LDL-C exposure: <4000 mg·year/dL, 4000-4999 mg·year/dL, 5000-5999 mg·year/dL, and ≥6000 mg·year/dL. RESULTS: The odds ratio of the lower quartile of FMD in the cholesterol-year-score <4000 mg·year/dL group was significantly higher than the odds ratios in the other groups. The odds ratio of the lower quartile of NID in the <4000 mg·year/dL group was significantly higher than the odds ratios in the 5000-5999 mg·year/dL and ≥6000 mg·year/dL groups. The odds ratio of the prevalence of CCA plaque in the <4000 mg·year/dL group was significantly higher than that in the ≥6000 mg·year/dL group. CONCLUSIONS: Endothelial dysfunction occurred from cumulative LDL-C exposure of 4000 mg·year/dL, vascular smooth muscle dysfunction occurred from cumulative LDL-C exposure of 5000 mg·year/dL, and prevalence of CCA plaque occurred from cumulative LDL-C exposure of 6000 mg·year/dL. CLINICAL TRIAL REGISTRY INFORMATION: http://www.umin.ac.jp (UMIN000012950, UMIN000012951, and UMIN000012952, UMIN000003409).

Gastrodin alleviates NTG-induced migraine-like pain via inhibiting succinate/HIF-1α/TRPM2 signaling pathway in trigeminal ganglion.

BACKGROUND: Increasing evidence highlights the involvement of metabolic disorder and calcium influx mediated by transient receptor potential channels in migraine; however, the relationship between these factors in the pathophysiology of migraine remains unknown. Gastrodin is the major component of the traditional Chinese medicine Tianma, which is extensively used in migraine therapy. PURPOSE: Our work aimed to explore the analgesic action of gastrodin and its regulatory mechanisms from a metabolic perspective. METHODS/RESULTS: After being treated with gastrodin, the mice were given nitroglycerin (NTG) to induce migraine. Gastrodin treatment significantly raised the threshold of sensitivity in response to both mechanical and thermal stimulus evidenced by von Frey and hot plate tests, respectively, and decreased total contact numbers in orofacial operant behavioral assessment. We found that the expression of transient receptor potential melastatin 2 (TRPM2) channel was increased in the trigeminal ganglion (TG) of NTG-induced mice, resulting in a sustained Ca2+ influx to trigger migraine pain. The content of succinate, a metabolic biomarker, was elevated in blood samples of migraineurs, as well as in the serum and TG tissue from NTG-induced migraine mice. Calcium imaging assay indicated that succinate insult elevated TRPM2-mediated calcium flux signal in TG neurons. Mechanistically, accumulated succinate upregulated hypoxia inducible factor-1α (HIF-1α) expression and promoted its translocation into nucleus, where HIF-1α enhanced TRPM2 expression through transcriptional induction in TG neurons, evidenced by luciferase reporter measurement. Gastrodin treatment inhibited TRPM2 expression and TRPM2-dependent Ca2+ influx by attenuating succinate accumulation and downstream HIF-1α signaling, and thereby exhibited analgesic effect. CONCLUSION: This work revealed that succinate was a critical metabolic signaling molecule and the key mediator of migraine pain through triggering TRPM2-mediated calcium overload. Gastrodin alleviated NTG-induced migraine-like pain via inhibiting succinate/HIF-1α/TRPM2 signaling pathway in TG neurons. These findings uncovered the anti-migraine effect of gastrodin and its regulatory mechanisms from a metabolic perspective and provided a novel theoretical basis for the analgesic action of gastrodin.

Microglia TREM1-mediated neuroinflammation contributes to central sensitization via the NF-κB pathway in a chronic migraine model.

BACKGROUND: Neuroinflammation, mediated by the activation of microglia, contributes to central sensitization, which is associated with the development of chronic migraine (CM). TREM1 receptors amplify the inflammatory response. However, their relationship to CM is unclear. Thus, this study endeavoured to elucidate the exact role of TREM1 in CM. METHODS: Nitroglycerin (NTG) was repeatedly administered intraperitoneally to establish the CM model. Mechanical and thermal sensitivities were assessed using von Frey filaments and hot plate assays. Using Western blotting, TREM1, NF-κB pathway, NLRP3 inflammasome components, and proinflammatory cytokines were all detected. Immunofluorescence was used to examine the cellular distribution of TREM1 and NLRP3, the number of microglia, immunoreactivity, and morphological changes. We examined the effects of TREM1 antagonists (LR12) and NF-κB inhibitors (PDTC) on pain behaviour, as well as the production of c-fos and CGRP. Additionally, we investigated whether LR12 and PDTC affect the activation of microglia and the NLRP3 inflammasome. We synthesized siRNA and TREM1-overexpressing plasmids to transfect BV2 cells treated with LPS and normal BV2 cells and treated TREM1-overexpressing BV2 cells with PDTC. The NF-κB pathway, NLRP3 inflammasome components, and proinflammatory cytokines were quantified using Western blotting. RESULTS: Following NTG administration, the expression of TREM1 was significantly upregulated and exclusively localized in microglia in the TNC, and was well co-localized with NLRP3. Furthermore, activation of the classical NF-κB pathway was observed. Pre-treatment with LR12 and PDTC effectively attenuated mechanical hypersensitivity, suppressed the expression of c-fos and CGRP, and inhibited NF-κB activity in CM mice. Additionally, inhibition of TREM1 and NF-κB activity mitigated NTG-induced microglia and NLRP3 activation, as well as proinflammatory cytokines production. In vitro, knockdown of TREM1 resulted in attenuated activation of the NF-κB pathway following lipopolysaccharide (LPS) treatment and reduced expression of NLRP3 inflammasome components as well as proinflammatory cytokines. After TREM1 overexpression, the NF-κB pathway was activated, NLRP3 inflammasome components and proinflammatory cytokines were upregulated, and PDTC reversed this phenomenon. CONCLUSIONS: Our findings suggest that TREM1 regulates microglia and NLRP3 activation via the NF-κB pathway, thereby contributing to central sensitization and implicating its involvement in chronic migraine pathogenesis.

Sudden diffuse spasm of multiple coronary arteries: A case report.

RATIONALE: Diffuse multivessel coronary artery spasm (DMV-CAS) was defined as a severe and reversible diffuse spasm occurring in more than 2 major coronary arteries, which is rare in clinical practice. Due to a wide lesion scope, DMV-CAS often occurs in the form of complications. It is not easy to be clinically diagnosed because it is too brief to be caught. Here, we report a rare case of spontaneous subtotal occlusion of 3 major coronary arteries induced by Vasalva action, which was confirmed in real-time by CAG. PATIENT CONCERNS: A 68-year-old man had sudden chest pain after forced defecation during hospitalization. The electrocardiogram showed transient ST segment elevation of the inferior wall lead, inversion of the anterior wall, and lateral wall leads T waves. Emergency CAG revealed elongated vessel beds in 3 coronary arteries and multiple diffuse stenosis, but none of the coronary arteries were completely occlusive. DIAGNOSES: Diagnoses of DMV-CAS were made based on CAG findings and postmedication response. INTERVENTIONS: Nitroglycerin was administered in the coronary arteries. The anti-vasospasm, antiplatelet aggregation and lipid-regulating drugs were administered orally. OUTCOMES: The patient was discharged on the 7th day with complete resolution of symptoms and normalization of the electrocardiography findings. No ischemic events occurred during a follow-up for 5 months. LESSONS: This case highlights the identification of multivessel diffuse coronary spasm and acute myocardial infarction, and the prevention of CAS triggers, which requires the attention of clinicians.

Nitroglycerin use and adverse clinical outcomes in elderly patients with acute coronary syndrome.

OBJECTIVE: The primary care for acute coronary syndrome (ACS) includes the administration of nitroglycerin (GTN). This study aimed to investigate the association between the use of GTN before percutaneous coronary intervention (PCI) for ACS and clinical outcomes. METHODS: Nine-hundred and forty-seven patients who underwent PCI for ACS were examined and classified into two groups: those who were treated with GTN before PCI (GTN group) and those who were not (non-GTN group). The incidence of major adverse cardiovascular events (MACE), which consist of all-cause mortality, non-fatal myocardial infarction, stroke and rehospitalisation for heart failure at 1 year, was compared between the two groups. RESULTS: This study identified 289 patients with ACS who used GTN preceding PCI. Pre-PCI systolic blood pressure was significantly lower in the GTN group than in the non-GTN group (median (IQR); 132.0 (110.0-143.5) mm Hg vs 134.0 (112.0-157.0) mm Hg, respectively, p=0.03). Multivariate Cox regression analysis indicated that GTN use preceding PCI showed an independent association with the incidence of MACE (HR 1.57; 95% CI 1.09-2.28; p=0.016). Overall, the incidence of MACE 1 year after PCI for ACS was significantly higher in the GTN group than in the non-GTN group (log-rank test, p=0.024); however, this trend was consistently found in elderly patients aged ≥75 years (p=0.002) but not in non-elderly patients aged <75 years (p=0.773). CONCLUSIONS: GTN use preceding PCI for ACS is associated with lower blood pressure and adverse clinical outcomes in elderly patients.

Dynamite plots in surgical research over 10 years: a meta-study using machine-learning analysis.

PURPOSE: Bar charts of numerical data, often known as dynamite plots, are unnecessary and misleading. Their tendency to alter the perception of mean's position through the within-the-bar bias and their lack of information on the distribution of the data are two of numerous reasons. The machine learning tool, Barzooka, can be used to rapidly screen for different graph types in journal articles.We aim to determine the proportion of original research articles using dynamite plots to visualize data, and whether there has been a change in their use over time. METHODS: Original research articles in nine surgical fields of research were sampled based on MeSH terms and then harvested using the Python-based biblio-glutton-harvester tool. After harvesting, they were analysed using Barzooka. Over 40 000 original research articles were included in the final analysis. The results were adjusted based on previous validation data with 95% confidence bounds. Kendall τ coefficient with the Mann-Kendall test for significance was used to determine the trend of dynamite plot use over time. RESULTS: Eight surgical fields of research showed a statistically significant decrease in use of dynamite plots over 10 years. Oral and maxillofacial surgery showed no significant trend in either direction. In 2022, use of dynamite plots, dependent on field and 95% confidence bounds, ranges from ~30% to 70%. CONCLUSION: Our results show that the use of dynamite plots in surgical research has decreased over time; however, use remains high. More must be done to understand this phenomenon and educate surgical researchers on data visualization practices.

Regulation of headache response and transcriptomic network by the trigeminal ganglion clock.

OBJECTIVE: To characterize the circadian features of the trigeminal ganglion in a mouse model of headache. BACKGROUND: Several headache disorders, such as migraine and cluster headache, are known to exhibit distinct circadian rhythms of attacks. The circadian basis for these rhythmic pain responses, however, remains poorly understood. METHODS: We examined trigeminal ganglion ex vivo and single-cell cultures from Per2::LucSV reporter mice and performed immunohistochemistry. Circadian behavior and transcriptomics were investigated using a novel combination of trigeminovascular and circadian models: a nitroglycerin mouse headache model with mechanical thresholds measured every 6 h, and trigeminal ganglion RNA sequencing measured every 4 h for 24 h. Finally, we performed pharmacogenomic analysis of gene targets for migraine, cluster headache, and trigeminal neuralgia treatments as well as trigeminal ganglion neuropeptides; this information was cross-referenced with our cycling genes from RNA sequencing data to identify potential targets for chronotherapy. RESULTS: The trigeminal ganglion demonstrates strong circadian rhythms in both ex vivo and single-cell cultures, with core circadian proteins found in both neuronal and non-neuronal cells. Using our novel behavioral model, we showed that nitroglycerin-treated mice display circadian rhythms of pain sensitivity which were abolished in arrhythmic Per1/2 double knockout mice. Furthermore, RNA-sequencing analysis of the trigeminal ganglion revealed 466 genes that displayed circadian oscillations in the control group, including core clock genes and clock-regulated pain neurotransmitters. In the nitroglycerin group, we observed a profound circadian reprogramming of gene expression, as 331 of circadian genes in the control group lost rhythm and another 584 genes gained rhythm. Finally, pharmacogenetics analysis identified 10 genes in our trigeminal ganglion circadian transcriptome that encode target proteins of current medications used to treat migraine, cluster headache, or trigeminal neuralgia. CONCLUSION: Our study unveiled robust circadian rhythms in the trigeminal ganglion at the behavioral, transcriptomic, and pharmacogenetic levels. These results support a fundamental role of the clock in pain pathophysiology. PLAIN LANGUAGE SUMMARY: Several headache diseases, such as migraine and cluster headache, have headaches that occur at the same time each day. We learned that the trigeminal ganglion, an important pain structure in several headache diseases, has a 24-hour cycle that might be related to this daily cycle of headaches. Our genetic analysis suggests that some medications may be more effective in treating migraine and cluster headache when taken at specific times of the day.