Migraine: epidemiology and systems of care

Migraine is a neurovascular disorder that affects over 1 billion people worldwide. Its widespread prevalence, and associated disability, have a range of negative and substantial effects not only on those immediately affected but also on their families, colleagues, employers, and society. To reduce this global burden, concerted efforts are needed to implement and improve migraine care that is supported by informed health-care policies. In this Series paper, we summarise the data on migraine epidemiology, including estimates of its very considerable burden on the global economy. First, we present the challenges that continue to obstruct provision of adequate care worldwide. Second, we outline the advantages of integrated and coordinated systems of care, in which primary and specialist care complement and support each other; the use of comprehensive referral and linkage protocols should enable continuity of care between these systems levels. Finally, we describe challenges in low and middle-income countries, including countries with poor public health education, inadequate access to medication, and insufficient formal education and training of health-care professionals resulting in misdiagnosis, mismanagement, and wastage of resources.

Migraine and the trigeminovascular system-40 years and counting

The underlying causes of migraine headache remained enigmatic for most of the 20th century. In 1979, The Lancet published a novel hypothesis proposing an integral role for the neuropeptide-containing trigeminal nerve. This hypothesis led to a transformation in the migraine field and understanding of key concepts surrounding migraine, including the role of neuropeptides and their release from meningeal trigeminal nerve endings in the mechanism of migraine, blockade of neuropeptide release by anti-migraine drugs, and activation and sensitisation of trigeminal afferents by meningeal inflammatory stimuli and upstream role of intense brain activity. The study of neuropeptides provided the first evidence that antisera directed against calcitonin gene-related peptide (CGRP) and substance P could neutralise their actions. Successful therapeutic strategies using humanised monoclonal antibodies directed against CGRP and its receptor followed from these findings. Nowadays, 40 years after the initial proposal, the trigeminovascular system is widely accepted as having a fundamental role in this highly complex neurological disorder and provides a road map for future migraine therapies.

Red and orange flags for secondary headaches in clinical practice: SNNOOP10 list

A minority of headache patients have a secondary headache disorder. The medical literature presents and promotes red flags to increase the likelihood of identifying a secondary etiology. In this review, we aim to discuss the incidence and prevalence of secondary headaches as well as the data on sensitivity, specificity, and predictive value of red flags for secondary headaches. We review the following red flags: (1) systemic symptoms including fever; (2) neoplasm history; (3) neurologic deficit (including decreased consciousness); (4) sudden or abrupt onset; (5) older age (onset after 65 years); (6) pattern change or recent onset of new headache; (7) positional headache; (8) precipitated by sneezing, coughing, or exercise; (9) papilledema; (10) progressive headache and atypical presentations; (11) pregnancy or puerperium; (12) painful eye with autonomic features; (13) posttraumatic onset of headache; (14) pathology of the immune system such as HIV; (15) painkiller overuse or new drug at onset of headache. Using the systematic SNNOOP10 list to screen new headache patients will presumably increase the likelihood of detecting a secondary cause. The lack of prospective epidemiologic studies on red flags and the low incidence of many secondary headaches leave many questions unanswered and call for large prospective studies. A validated screening tool could reduce unneeded neuroimaging and costs.

Migraine: integrated approaches to clinical management and emerging treatments

Migraine is a highly disabling neurological disorder that directly affects more than 1 billion individuals worldwide. Available treatment options differ between countries and include acute, preventive, and non-pharmacological therapies. Because of major progress in the understanding of migraine pathogenesis, novel mechanism-based medications have emerged and expanded the armamentarium of treatments. We provide a comprehensive overview of the current standard of care that will enable informed clinical management. First, we discuss the efficacy, tolerability, and safety profile of various pharmacological therapies for acute and preventive treatment of migraine. Second, we review the current knowledge on non-pharmacological therapies, such as neuromodulation and biobehavioural approaches, which can be used for a multidisciplinary approach to clinical management. Third, we emphasise that any effective treatment strategy starts with building a therapeutic plan tailored to individual clinical characteristics, preferences, and needs. Finally, we explore the outlook of emerging mechanism-based treatments that could address unmet challenges in clinical management of migraine.

Delayed treatment with intravenous basic fibroblast growth factor reduces infarct size following permanent focal cerebral ischemia in rats

Basic fibroblast growth factor (bFGF) is a polypeptide that supports the survival of brain cells (including neurons, glia, and endothelia) and protects neurons against a number of toxins and insults in vitro. This factor is also a potent dilator of cerebral pial arterioles in vivo. In previous studies, we found that intraventricularly administered bFGF reduced infarct volume in a model of focal cerebral ischemia in rats. In the current study, bFGF (45 micrograms/kg/h) in vehicle, or vehicle alone, was infused intravenously for 3 h, beginning at 30 min after permanent middle cerebral artery occlusion by intraluminal suture in mature Sprague-Dawley rats. After 24 h, neurological deficit (as assessed by a 0- to 5-point scale, with 5 = most severe) was 2.6 +/- 1.0 in vehicle-treated and 1.5 +/- 1.3 in bFGF-treated rats (mean +/- SD; N = 12 vs. 11; p = 0.009). Infarct volume was 297 +/- 65 mm3 in vehicle- and 143 +/- 135 mm3 in bFGF-treated animals (p = 0.002). During infusion, there was a modest decrease in mean arterial blood pressure but no changes in arterial blood gases or core or brain temperature in bFGF-treated rats. Autoradiography following intravenous administration of 111In-labeled bFGF showed that labeled bFGF crossed the damaged blood-brain barrier to enter the ischemic (but not the nonischemic) hemisphere. Whether the infarct-reducing effects of bFGF depend on intraparenchymal or intravascular mechanisms requires further study.

Myofascial trigger points in migraine and tension-type headache

BACKGROUND

A myofascial trigger point is defined as a hyperirritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band. It has been suggested that myofascial trigger points take part in chronic pain conditions including primary headache disorders. The aim of this narrative review is to present an overview of the current imaging modalities used for the detection of myofascial trigger points and to review studies of myofascial trigger points in migraine and tension-type headache.

FINDINGS

Different modalities have been used to assess myofascial trigger points including ultrasound, microdialysis, electromyography, infrared thermography, and magnetic resonance imaging. Ultrasound is the most promising of these modalities and may be used to identify MTrPs if specific methods are used, but there is no precise description of a gold standard using these techniques, and they have yet to be evaluated in headache patients. Active myofascial trigger points are prevalent in migraine patients. Manual palpation can trigger migraine attacks. All intervention studies aiming at trigger points are positive, but this needs to be further verified in placebo-controlled environments. These findings may imply a causal bottom-up association, but studies of migraine patients with comorbid fibromyalgia syndrome suggest otherwise. Whether myofascial trigger points contribute to an increased migraine burden in terms of frequency and intensity is unclear. Active myofascial trigger points are prevalent in tension-type headache coherent with the hypothesis that peripheral mechanisms are involved in the pathophysiology of this headache disorder. Active myofascial trigger points in pericranial muscles in tension-type headache patients are correlated with generalized lower pain pressure thresholds indicating they may contribute to a central sensitization. However, the number of active myofascial trigger points is higher in adults compared with adolescents regardless of no significant association with headache parameters. This suggests myofascial trigger points are accumulated over time as a consequence of TTH rather than contributing to the pathophysiology.

CONCLUSIONS

Myofascial trigger points are prevalent in both migraine and tension-type headache, but the role they play in the pathophysiology of each disorder and to which degree is unclarified. In the future, ultrasound elastography may be an acceptable diagnostic test.

Clinical value of routine preoperative magnetic resonance imaging in adolescent idiopathic scoliosis. A prospective study of three hundred and twenty-seven patients

BACKGROUND

The prevalence of intraspinal pathology associated with scoliosis has been reported to be as high as 26% in some series, and, on the basis of this finding, preoperative magnetic resonance imaging is used in the screening of patients with adolescent idiopathic scoliosis. However, this practice continues to be highly controversial. In order to better resolve this issue, we performed what we believe to be the largest prospective study to evaluate the need for preoperative magnetic resonance imaging in patients with adolescent idiopathic scoliosis requiring arthrodesis of the spine.

METHODS

A total of 327 consecutive patients with adolescent idiopathic scoliosis were evaluated between December 1991 and March 1999. All patients in the study presented with an adolescent idiopathic scoliosis curve pattern and had a complete physical and neurologic examination. Magnetic resonance imaging of the brain and the spinal cord were performed as part of their preoperative work-up.

RESULTS

Seven patients had an abnormality noted on magnetic resonance imaging. These abnormalities included a spinal cord syrinx in two patients (0.6%) and an Arnold-Chiari type-I malformation in four (1.2%). One patient had an abnormal fatty infiltration of the tenth thoracic vertebral body. No patient required neurosurgical intervention or additional work-up. All patients who underwent spinal arthrodesis with segmental instrumentation tolerated the surgery without any immediate or delayed neurologic sequelae.

CONCLUSIONS

The fact that magnetic resonance imaging did not detect any important pathology in the large number of patients in this study strongly suggests that magnetic resonance imaging is not indicated prior to arthrodesis of the spine in patients with an adolescent idiopathic scoliosis curve pattern and a normal physical and neurologic examination.

Orphanin FQ/nociceptin attenuates motor stimulation and changes in nucleus accumbens extracellular dopamine induced by cocaine in rats

RATIONALE

Orphanin FQ (OFQ; also known as nociceptin), the endogenous ligand of the opioid receptor-like receptor, injected intracerebroventricularly (i.c.v.) decreases basal motor activity and basal extracellular levels of dopamine (DA) in the nucleus accumbens (Nuc Acc) in rats.

OBJECTIVE

The present study was designed to determine if OFQ similarly attenuates cocaine-induced motor stimulation and to determine if this effect is dependent on attenuation of the increase in extracellular DA.

METHODS

After a 1-h adaptation period, rats were injected with either artificial cerebrospinal fluid or OFQ (3-30 nmol, i.c.v.) 5 min prior to cocaine (10 mg/kg, i.p.) or apomorphine (3 mg/kg, i.p.) administration and the total distance traveled was measured for a further 1 h. In a separate experiment, changes in extracellular DA were monitored by microdialysis following cocaine and OFQ treatment in anesthetized rats.

RESULTS

OFQ dose-dependently attenuated both basal and cocaine-induced motor stimulation. OFQ (30 nmol, i.c.v.) also attenuated both the basal and the cocaine-induced increase in extracellular DA in the Nuc Acc. OFQ, at the highest dose, also decreased the motor stimulation induced by apomorphine.

CONCLUSIONS

Our results suggest that the modulatory effect of OFQ on locomotor activity is not solely due to its inhibitory action on extracellular DA in the Nuc Acc.

Increased expression of basic fibroblast growth factor (bFGF) following focal cerebral infarction in the rat

Basic fibroblast growth factor (bFGF) is a polypeptide with potent trophic effects on brain neurons, glia, and endothelial cells. In the current study, we used Northern blotting, in situ hybridization, and immunohistochemical techniques to examine bFGF expression in brain following focal infarction due to permanent occlusion of the proximal middle cerebral artery in mature Sprague-Dawley rats. We found a four-fold increase in bFGF mRNA in tissue surrounding focal infarcts at 1 day after ischemia. In situ hybridization showed that this increase was found throughout several structures in the ipsilateral hemisphere, including frontoparietal, temporal, and cingulate cortex, as well as in caudoputamen, globus pallidus, septal nuclei, nucleus accumbens, and olfactory tubercle. Increased bFGF mRNA expression was associated with cells having the distinct morphological appearance of astroglia in these structures. Immunohistochemistry showed an increase in the size and number of bFGF-immunoreactive (IR) nuclei in these same structures, as well as a shift from nuclear to nuclear plus cytoplasmic localization of immunoreactivity, beginning at 1 day, and peaking at 3 days after ischemia. Double immunostaining identified bFGF-IR cells as astroglia in these structures. (An exception was the piriform cortex, in which both increased bFGF mRNA levels and increased bFGF-IR was found in neurons at 1 day after ischemia). Overall, the peak of increased bFGF expression preceded the peak in expression of the astroglial marker GFAP within the ipsilateral hemisphere. Increased bFGF expression may play an important role in the glial, neuronal, and vascular changes occurring after focal infarction.

Therapeutic novelties in migraine: new drugs, new hope?

Background

In the past decade, migraine research has identified novel drug targets. In this review, we discuss recent data on emerging anti-migraine therapies.

Main body

The development of ditans, gepants and anti-calcitonin gene-related peptide monoclonal antibodies for the treatment of migraine is one of the greatest advances in the migraine field. Lasmiditan, rimegepant and ubrogepant will extend our therapeutic armamentarium for managing acute migraine attacks when triptans are not effective or contraindicated due to cardiovascular disorders. The monoclonal antibodies are migraine specific prophylactic drugs with high responder rates and favorable adverse event profiles. Furthermore, they offer convenient treatment regimens of 4- or 12-week intervals.

Conclusion

Collectively, novel migraine therapies represent a major progress in migraine treatment and will undoubtedly transform headache medicine.

Variability Timescale and Spectral Index of Sgr A* in the Near Infrared: Approximate Bayesian Computation Analysis of the Variability of the Closest Supermassive Black Hole

Sagittarius A* (Sgr A*) is the variable radio, near-infrared (NIR), and X-ray source associated with accretion onto the Galactic center black hole. We present an analysis of the most comprehensive NIR variability data set of Sgr A* to date: eight 24 hr epochs of continuous monitoring of Sgr A* at 4.5 μm with the IRAC instrument on the Spitzer Space Telescope, 93 epochs of 2.18 μm data from Naos Conica at the Very Large Telescope, and 30 epochs of 2.12 μm data from the NIRC2 camera at the Keck Observatory, in total 94,929 measurements. A new approximate Bayesian computation method for fitting the first-order structure function extracts information beyond current fast Fourier transformation (FFT) methods of power spectral density (PSD) estimation. With a combined fit of the data of all three observatories, the characteristic coherence timescale of Sgr A* isτ b = 243 - 57 + 82 minutes (90% credible interval). The PSD has no detectable features on timescales down to 8.5 minutes (95% credible level), which is the ISCO orbital frequency for a dimensionless spin parameter a = 0.92. One light curve measured simultaneously at 2.12 and 4.5 μm during a low flux-density phase gave a spectral index α s = 1.6 ± 0.1( F ν ∝ ν - α s ) . This value implies that the Sgr A* NIR color becomes bluer during higher flux-density phases. The probability densities of flux densities of the combined data sets are best fit by log-normal distributions. Based on these distributions, the Sgr A* spectral energy distribution is consistent with synchrotron radiation from a non-thermal electron population from below 20 GHz through the NIR.

Peptides from the amino terminal mdm-2-binding domain of p53, designed from conformational analysis, are selectively cytotoxic to transformed cells

We have synthesized three peptides from the mdm-2 binding domain of human p53, residues 12-26 (PPLSQETFSDLWKLL), residues 12-20, and 17-26. To enable transport of the peptides across the cell membrane and at the same time to maximize the active mdm-2 binding alpha-helical conformation for these peptides, each was attached at its carboxyl terminus to the penetratin sequence, KKWKMRRNQFWVKVQRG, that contains many positively charged residues that stabilize an alpha-helix when present on its carboxyl terminal end. All three peptides were cytotoxic to human cancer cells in culture, whereas a control, unrelated peptide attached to the same penetratin sequence had no effect on these cell lines. The same three cytotoxic peptides had no effect on the growth of normal cells, including human cord blood-derived stem cells. These peptides were as effective in causing cell death in p53-null cancer cells as in those having mutant or normal p53. Peptide-induced cell death is not accompanied by expression of apoptosis-associated proteins such as Bax and waf(p21). Based on these findings, we conclude that the antiproliferative effects of these p53-derived peptides are not completely dependent on p53 activity and may prove useful as general anticancer agents.

New cyclic peptides from the ascidian Lissoclinum patella

Four new cyclic peptides, patellamide G (2) and ulithiacyclamides E-G (3-5), along with the known patellamides A-C (6-8) and ulithiacyclamide B (9), were isolated from the ascidian Lissoclinum patella collected in Pohnpei, Federated States of Micronesia. The planar structures of these peptides were determined from 1D and 2D 1H and 13C NMR spectra. The absolute stereochemistries of the amino acid units, except for cysteine, were assigned by chiral GC analysis of N(O)-trifluoroacetyl isopropyl ester derivatives of amino acids obtained by acid hydrolysis of the intact and ozonized peptides. The structures of ulithiacyclamides E-G (3-5) were confirmed by chemical conversion. Patellamides B (7) and C (8) exhibited in vitro modulation of multidrug resistance in CEM/VBL100 cells.

Clinical features of visual migraine aura: a systematic review

Background

Migraine aura (MA) is a common and disabling neurological condition, characterized by transient visual, and less frequently sensory and dysphasic aura disturbances.

MA is associated with an increased risk of cardiovascular disorders and is often clinically difficult to distinguish from other serious neurological disorders such as transient ischemic attacks and epilepsy. Optimal clinical classification of MA symptoms is important for more accurate diagnosis and improved understanding of the pathophysiology of MA through clinical studies.

Main body

A systematic review of previous prospective and retrospective systematic recordings of visual aura symptoms (VASs) was performed to provide an overview of the different types of visual phenomena occurring during MA and their respective frequencies in patients. We found 11 retrospective studies and three prospective studies systematically describing VASs. The number of different types of VASs reported by patients in the studies ranged from two to 23. The most common were flashes of bright light, “foggy” vision, zigzag lines, scotoma, small bright dots and ‘like looking through heat waves or water’.

Conclusions

We created a comprehensive list of VAS types reported by migraine patients based on all currently available data from clinical studies, which can be used for testing and validation in future studies. We propose that, based on this work, an official list of VAS types should be developed, preferably within the context of the International Classification of Headache Disorders of the International Headache Society.

Diversity of Veillonella spp. from sound and carious sites in children

Detailed data on the distribution of Veillonella in caries-free and caries-active subjects are scarce. We hypothesized that the diversity of the genus would be lower in caries lesions than in plaque from caries-free individuals. The proportions of Veillonella were not significantly different in the two groups. All isolates (n = 1308) were genotyped by REP-PCR, and different genotypes (n = 170) were identified by 16S rRNA, dnaK, and rpoB sequencing. V. parvula, V. dispar, and V. atypica were in both groups, V. denticariosi only in caries lesions, and V. rogosae only from the caries-free individuals (p < 0.009). Lesions were more likely to harbor a single predominant species (p = 0.0018). The mean number of genotypes in the lesions was less than in the fissure (p < 0.001) or buccal (p = 0.011) sites. The Veillonella from caries-free sites were more diverse than those from caries lesions, and may be related to the acidic environment of caries lesions.

Real-world long-term efficacy and safety of erenumab in adults with chronic migraine: a 52-week, single-center, prospective, observational study

BACKGROUND

Clinical trials have shown that erenumab is effective and well-tolerated for the preventive treatment of chronic migraine. To extend the results from clinical trials, we assessed the real-world efficacy and safety of erenumab in patients with chronic migraine from the outpatient clinic at the Danish Headache Center.

METHODS

A 52-week, single-center, prospective, observation study of erenumab in adults with chronic migraine who are eligible for treatment with monoclonal antibodies against CGRP or its receptor in Denmark. The primary outcome was defined as proportion of patients who achieved ≥ 30% reduction in monthly migraine days (MMDs) from baseline to weeks 9-12.

RESULTS

A total of 300 adult patients with chronic migraine were enrolled and received at least one dose of erenumab. At baseline, the mean (SD) number of monthly headache days was 23 ± 4.9 and mean number of MMDs was 16.8 ± 6.4. Of 300 enrolled patients, 273 (91.0%) patients completed 12 weeks of treatment, and 119 (39.7%) completed 52 weeks of treatment. The number of patients who achieved ≥ 30% reduction in MMDs from baseline to weeks 9-12 was 195 (71.4%) of 273 patients. Sustained ≥ 30% reduction in MMDs at all assessment periods throughout the 52-week treatment period was achieved by 102 (34%) of 300 patients. Adverse events occurred in 220 (73.3%) out of 300 patients. The most common adverse event was constipation. Treatment discontinuation due to lack of tolerability occurred in 41 (13.7%) patients.

CONCLUSIONS

Among adult patients with chronic migraine and previous failure of medications for migraine prevention, erenumab was found to be effective and well-tolerated.

Treatment satisfaction and persistence among postmenopausal women on osteoporosis medications: 12-month results from POSSIBLE US™

SUMMARY

Women in POSSIBLE US™ who expressed greater treatment satisfaction at study entry were more likely to persist with osteoporosis therapy over a 1-year period. Lower satisfaction among women with moderate/severe side effects increased the risk of discontinuation/switching by 67%. Treatment satisfaction and side effect experience influence osteoporosis medication adherence.

INTRODUCTION

Non-adherence is common among women using postmenopausal osteoporosis (PMO) medications. We describe the association between treatment satisfaction, measured with the Treatment Satisfaction Questionnaire for Medication (TSQM), and the risk of discontinuation/switching PMO medications using patient-reported data from a large, longitudinal cohort study.

METHODS

Data from 2,405 participants in the Prospective Observational Scientific Study Investigating Bone Loss Experience (POSSIBLE US™) Study were evaluated. Cox proportional hazards regression was used to estimate hazard ratios (HR) for the association between treatment satisfaction at study entry and self-reported discontinuation/switching of pharmacologic PMO medications over a 1-year follow-up period. Logistic regression was used to evaluate relationships between treatment satisfaction, lifestyle behaviors, and compliance with bisphosphonate dosing instructions.

RESULTS

Median TSQM scores were highest (indicating greatest satisfaction) for the side effects domain [n = 1,182; median = 87.5 (Q1 = 75.0, Q3 = 100.0)] and lowest for global satisfaction [n = 2,340; median = 64.0 (Q1 = 55.7, Q3 = 77.7)]. Median scores decreased for the side effects and global satisfaction domains as patient-reported side effect severity increased. Women with higher satisfaction were less likely to discontinue/switch medications than women with lower scores (adjusted HRs for convenience 0.73, 95% CI = 0.63-0.85; effectiveness 0.82, 95% CI = 0.70-0.97; and global satisfaction 0.73, 95% CI = 0.63-0.85). Lower treatment satisfaction was particularly influential among women who reported moderate/severe side effects (HR = 0.60, 95% CI = 0.37-0.97).

CONCLUSIONS

Lower treatment satisfaction was associated with a 22% (1/0.82) to 67% (1/0.60) increased risk of discontinuation/switching osteoporosis medication during 1 year of follow-up.

Persistence and switching patterns among women with varied osteoporosis medication histories: 12-month results from POSSIBLE US

During the first year of Prospective Observational Scientific Study Investigating Bone Loss Experience (POSSIBE US), many women transitioned (i.e., discontinued or switched) from their baseline osteoporosis medication. Participants not on stable therapy at entry, with side effects, and with poor physical status were at higher risk of transitioning. Understanding factors associated with persistence may lead to improved outcomes.

INTRODUCTION

Postmenopausal osteoporosis (PMO) medication use patterns may differ by treatment history and drug class. We describe these patterns among patients in primary care settings using patient-reported data.

METHODS

Data from 3,006 participants of the POSSIBLE US were used to estimate the probability of a baseline PMO medication transition (i.e., discontinuation or switch) and hazard ratios (HRs) for predictors of these transitions.

RESULTS

One year after study entry, the probability of persisting with a baseline medication was 66% (95% CI: 64-68%). After adjusting for age and osteoporosis diagnosis, factors at entry independently associated with a higher risk of baseline medication transition were treatment status cohort, side effect severity, and OPAQ-SV physical function score. Compared to participants stable on therapy at entry, others had a higher risk, ranging from HR = 1.59 (95% CI: 1.36-1.85) for those new to therapy to HR = 2.00 (95% CI: 1.27-3.15) for those who recently augmented therapy at entry. Participants reporting moderate (HR = 1.31, 95% CI: 1.09-1.57) or severe (HR = 1.88, 95% CI: 1.49-2.39) side effects had a higher risk than those not reporting side effects. Participants reporting Osteoporosis Assessment Questionnaire-Short Version physical function scores in the lowest tertile had a higher risk (HR = 1.27, 95% CI: 1.07-1.52) than those reporting scores in the highest tertile.

CONCLUSION

Baseline osteoporosis medication transitions were common in the first year of POSSIBLE US. Participants not on stable therapy at entry, or who reported severe side effects, or had poor physical health status were at higher risk for these transitions.

New Pharmacogenomics Research Network: An Open Community Catalyzing Research and Translation in Precision Medicine

The goal of pharmacogenomics research is to discover genetic polymorphisms that underlie variation in drug response. Increasingly, pharmacogenomics research involves large numbers of patients and the application of new technologies and methodologies to enable discovery. The Pharmacogenomics Research Network (PGRN) has become a community-driven network of investigators spanning scientific and clinical disciplines. Here, we highlight the activities and types of resources that enable PGRN members to enhance and drive basic and translational research in pharmacogenomics.

Illumina short-read and MinION long-read WGS to characterize the molecular epidemiology of an NDM-1 Serratia marcescens outbreak in Romania

Background and Objectives

Serratia marcescens is an emerging nosocomial pathogen, and the carbapenemase bla_NDM has been reported in several surveys in Romania. We aimed to investigate the molecular epidemiology of S. marcescens in two Romanian hospitals over 2010–15, including a neonatal NDM-1 S. marcescens outbreak.

Methods

Isolates were sequenced using Illumina technology together with carbapenem-non-susceptible NDM-1-positive and NDM-1-negative Klebsiella pneumoniae and Enterobacter cloacae to provide genomic context. A subset was sequenced with MinION to fully resolve NDM-1 plasmid structures. Resistance genes, plasmid replicons and ISs were identified in silico for all isolates; an annotated phylogeny was reconstructed for S. marcescens. Fully resolved study NDM-1 plasmid sequences were compared with the most closely related publicly available NDM-1 plasmid reference.

Results

44/45 isolates were successfully sequenced (S. marcescens, n = 33; K. pneumoniae, n = 7; E. cloacae, n = 4); 10 with MinION. The S. marcescens phylogeny demonstrated several discrete clusters of NDM-1-positive and -negative isolates. All NDM-1-positive isolates across species harboured a pKOX_NDM1-like plasmid; more detailed comparisons of the plasmid structures demonstrated a number of differences, but highlighted the largely conserved plasmid backbones across species and hospital sites.

Conclusions

The molecular epidemiology is most consistent with the importation of a pKOX_NDM1-like plasmid into Romania and its dissemination amongst K. pneumoniae/E. cloacae and subsequently S. marcescens across hospitals. The data suggested multiple acquisitions of this plasmid by S. marcescens in the two hospitals studied; transmission events within centres, including a large outbreak on the Targu Mures neonatal unit; and sharing of the pKOX_NDM1-like plasmid between species within outbreaks.

Chromosome evolution: the junction of mammalian chromosomes in the formation of mouse chromosome 10

During evolution, chromosomes are rearranged and become fixed into new patterns in new species. The relatively conservative nature of this process supports predictions of the arrangement of ancestral mammalian chromosomes, but the basis for these rearrangements is unknown. Physical mapping of mouse chromosome 10 (MMU 10) previously identified a 380-kb region containing the junction of material represented in human on chromosomes 21 (HSA 21) and 22 (HSA 22) that occurred in the evolutionary lineage of the mouse. Here, acquisition of 275 kb of mouse genomic sequence from this region and comparative sequence analysis with HSA 21 and HSA 22 narrowed the junction from 380 kb to 18 kb. The minimal junction region on MMU 10 contains a variety of repeats, including an L32-like ribosomal element and low-copy sequences found on several mouse chromosomes and represented in the mouse EST database. Sequence level analysis of an interchromosomal rearrangement during evolution has not been reported previously.

Rapid identification of virulence genes in enterotoxigenic Escherichia coli isolates associated with diarrhoea in Queensland piggeries

OBJECTIVE

To identify virulence genes in enterotoxigenic E coli (ETEC) isolates associated with diarrhoea in neonatal, 1 to 3 week-old and weaned pigs in southeast Queensland.

DESIGN

Multiplex PCR and serotyping were applied to E coli isolates obtained over a 5-year period (1998-2002) from cases diagnosed at Toowoomba Veterinary Laboratory.

PROCEDURE

A total of 126 isolates from 25 different Queensland piggeries were tested for haemolytic activity on 5% sheep blood agar and by multiplex PCR for the presence of five commonly recognised fimbrial (F4, F5, F6, F41 and F18) and three enterotoxin genes (STa, STb, LT). A subset of 62 representative isolates were serotyped by slide agglutination. For comparative purposes, multiplex PCR was also performed on the DNA of 31 ETEC isolates from 9 serotypes originating from piggeries in southern New South Wales.

RESULTS

A total of 113 (89.7%) of the isolates from Queensland possessed ETEC virulence genes, including 14 of 15 isolates from neonatal pigs (93.3%), 18 of 23 isolates from 1 to 3 week old pigs (78.3%) and 81 of 88 isolates from weaned pigs (92.1%). F4:STa:STb:LT (serotype O149) was the most prevalent pathotype in neonatal and 1-3 week old pigs and F4:STa:STb:LT (serotype O149) and F18:STa:STb:LT (serotype O141) were most prevalent in weaned pigs. In comparison, isolates obtained from neonatal pigs from New South Wales belonged to a more diverse range of pathotypes and serotypes.

CONCLUSION

Multiplex PCR was a rapid and specific method for detecting the presence of ETEC virulence genes in porcine E coli isolates. For isolates obtained from cases of suspected colibacillosis in Queensland, growth of a heavy pure culture of haemolytic E coli was a sensitive prognostic indicator of the presence of ETEC virulence genes in the isolate. ETEC pathotypes and serotypes remained stable in Queensland piggeries over the five-year study period and appear to have changed little over the last three decades.

Migraine attacks are of peripheral origin: the debate goes on

BACKGROUND

Despite the pervasiveness of migraine, the underlying pathophysiological mechanisms initiating migraine attacks are far from well understood and are matter of scientific debate.

OBJECTIVE

In this narrative review, we discuss key evidence for that suggest a peripheral origin or central origin and provide directions for future studies that may provide further clarification.

DISCUSSION

Migraine pathogenesis is considered to involve the trigeminovascular system, a term that encompasses the trigeminal nerve and its axonal projections to the intracranial blood vessels. Beyond any doubt both peripheral and central mechanisms are involved in migraine pathogenesis, but an unresolved question is the how the initial activation occurs in a migraine attack. Evidence favoring a peripheral origin of migraine attacks, i.e., initial events occur outside of the blood-brain barrier, include the importance of sensitization of perivascular sensory afferents early on in a migraine attack. Evidence favoring a central origin include the occurrence of prodromal symptoms, migraine aura, and activation of structures within the central nervous system early in and during a migraine attack.

CONCLUSIONS

Both peripheral and central mechanisms are likely involved in a migraine attack, e.g., peripheral nociceptive input is necessary for pain transmission and cortical activity is necessary for pain perception. Yet, the debate of whether migraine attacks are initiated a peripheral or central site remains unresolved. The increased focus on prodromal symptoms and on the development of a human model of migraine aura will possibly provide key arguments needed to answer this question in the near future. Until then, we cannot draw firm conclusions and the debate goes on.

VIDEO LINK

Video recording of the debate held at the 1st International Conference on Advances in Migraine Sciences (ICAMS 2022, Copenhagen, Denmark) is available at: https://www.youtube.com/watch?v=NC0nlcKohz0 .

Migraine and light: A narrative review

OBJECTIVE

In this narrative review, we summarize clinical and experimental data on the effect of light in migraine and discuss future prospects.

BACKGROUND

Effective nonpharmacological treatment of hypersensitivity to light in migraine is an unmet clinical need. Current management strategies primarily consist of seeking a dark room and avoiding light exposure. Advances in the past 2 decades have improved our understanding of the underlying pathophysiology of how migraine is influenced by light. This may provide promising avenues for novel approaches in clinical management.

METHODS

We searched MEDLINE for articles published from database inception up to September 1, 2021. We used the search term "migraine" with the search terms "light," "photophobia," "treatment," "trigger," "circadian rhythm," "environment," and/or "pathophysiology."

RESULTS

Light is commonly reported as a trigger factor of migraine attacks, however, early manifestation of photophobia and false attribution is likely the actual cause based on data deriving from retrospective, prospective, and experimental studies. The most common photophobia symptoms in migraine are exacerbation of headache by light and abnormal sensitivity to light with the underlying neural pathways likely being dependent on ongoing activity in the trigeminovascular system. Clinical studies and experimental models have identified mediators of photophobia and uncovered narrow wavebands of the light spectrum that may reduce pain intensity during a migraine attack. Consequently, novel devices have undergone exploratory clinical trials with promising results.

CONCLUSION

False attribution is likely the reason why light is commonly reported as a trigger factor of migraine attacks, and a prospective confirmation is required to prevent unnecessary avoidance. The observation that individuals with migraine are not equally photophobic to all wavebands of the light spectrum opens the potential for innovative pain management strategies. In this context, using human-centric lighting (also called integrative lighting) to mimic the natural daylight cycle and avoid harmful wavebands through modern technology may prove beneficial. Future research should identify direct and indirect consequences of light and other environmental factors in migraine to fill out knowledge gaps and enable evidence-based care strategies within institutions, work environments, and other settings.

CGRP-induced migraine-like headache in persistent post-traumatic headache attributed to mild traumatic brain injury

OBJECTIVE

To ascertain whether intravenous infusion of calcitonin gene-related peptide (CGRP) can induce migraine-like headache in people with persistent post-traumatic headache attributed to mild traumatic brain injury (TBI) and no pre-existing migraine.

METHODS

A non-randomized, single-arm, open-label study at a single site in Denmark. Eligible participants were aged 18 to 65 years and had a known history of persistent post-traumatic headache attributed to mild TBI for ≥ 12 months. All participants received continuous intravenous infusion of CGRP (1.5 µg/min) over 20 min. A headache diary was used to collect outcome data until 12 h after the start of CGRP infusion. The primary end point was the incidence of migraine-like headache during 12-hour observational period.

RESULTS

A total of 60 participants completed the study protocol and provided data for the analysis of the primary end point. The median age was 32.5 (IQR, 25.5-43.0) years; 43 participants (72%) were female. Following CGRP infusion, 43 (72%) of 60 participants developed migraine-like headache during the 12-hour observational period. The median time to peak headache intensity was 40 min (IQR, 20-60), and the median peak headache intensity was 6 (IQR, 5-8) on the 11-point numeric rating scale.

CONCLUSION

Intravenous infusion of CGRP is a potent inducer of migraine-like headache in people with persistent post-traumatic headache attributed to mild TBI. This observation underscores the importance of CGRP in the genesis of migraine-like headache that is often experienced by individuals who are afflicted by persistent post-traumatic headache. Further research is warranted to ascertain whether other signaling molecules also contribute to the disease mechanisms underlying post-traumatic headache.