Genetic correlations between migraine and carpal tunnel syndrome

BACKGROUND

Surgical deactivation of extracranial nerve trigger sites is now well-established as an effective treatment for migraine headache. Parallels have been drawn to median nerve decompression for carpal tunnel syndrome (CTS), and two previous studies have demonstrated an association between migraine and CTS. We sought to: (1) substantiate these findings in a considerably larger UK cohort, and; (2) investigate potential genetic associations between the two disorders.

METHODS

Nested case-control studies were conducted in the UK Biobank cohort of 401,656 individuals. Odds ratios were calculated for the association between migraine and CTS in the overall cohort and sex-stratified subsets. Genetic correlation between migraine and CTS was interrogated by linkage disequilibrium score regression (LDSC), leveraging data from published genome-wide association studies. Regions of genetic overlap were identified by Multi-Trait Analysis of GWAS (MTAG) and Cross-Phenotype Association (CPASSOC).

RESULTS

Migraine and CTS show a significant epidemiological association within UK Biobank (OR=1.14, 95% CI: 1.04-1.25, p=0.0058), which is specific to females (OR=1.15; 95% CI: 1.04-1.28, p=0.0057) and not males (OR=1.07; 95% CI: 0.82-1.40, p=0.61). Genetic analysis demonstrated a significant positive genetic correlation between the two disorders (rg=0.13, p=0.0039), and implicated the TRIM32 locus on chromosome 9 as a region of genetic overlap.

CONCLUSIONS

This study replicates past reports of an epidemiological association between CTS and migraine, albeit in females only. This association is underpinned by a genetic correlation, with shared genetic susceptibility at the TRIM32 locus. Our data adds credibility to the notion that an element of entrapment neuropathy underlies migraine pathophysiology.

Author Correction: Super-resolution microscopy compatible fluorescent probes reveal endogenous glucagon-like peptide-1 receptor distribution and dynamics

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Super-resolution microscopy compatible fluorescent probes reveal endogenous glucagon-like peptide-1 receptor distribution and dynamics

The glucagon-like peptide-1 receptor (GLP1R) is a class B G protein-coupled receptor (GPCR) involved in metabolism. Presently, its visualization is limited to genetic manipulation, antibody detection or the use of probes that stimulate receptor activation. Herein, we present LUXendin645, a far-red fluorescent GLP1R antagonistic peptide label. LUXendin645 produces intense and specific membrane labeling throughout live and fixed tissue. GLP1R signaling can additionally be evoked when the receptor is allosterically modulated in the presence of LUXendin645. Using LUXendin645 and LUXendin651, we describe islet, brain and hESC-derived β-like cell GLP1R expression patterns, reveal higher-order GLP1R organization including membrane nanodomains, and track single receptor subpopulations. We furthermore show that the LUXendin backbone can be optimized for intravital two-photon imaging by installing a red fluorophore. Thus, our super-resolution compatible labeling probes allow visualization of endogenous GLP1R, and provide insight into class B GPCR distribution and dynamics both in vitro and in vivo.

Glucagon-like peptide-1 receptor is an important regulator of appetite and glucose homeostasis. Here the authors describe super-resolution microscopy and in vivo imaging compatible fluorescent probes, which reveal endogenous glucagon-like peptide-1 receptor distribution and dynamics in islets and brain.

Ureidopeptide GLP-1 analogues with prolonged activity in vivo via signal bias and altered receptor trafficking

The high demand of the pharmaceutical industry for new modalities to address the diversification of biological targets with large surfaces of interaction led us to investigate the replacement of α-amino acid residues with ureido units at selected positions in peptides to improve potency and generate effective incretin mimics. Based on molecular dynamics simulations, N-terminally modified GLP-1 analogues with a ureido residue replacement at position 2 were synthesized and showed preservation of agonist activity while exhibiting a substantial increase in stability. This enabling platform was applied to exenatide and lixisenatide analogues to generate two new ureidopeptides with antidiabetic properties and longer duration of action. Further analyses demonstrated that the improvement was due mainly to differences in signal bias and trafficking of the GLP-1 receptor. This study demonstrates the efficacy of single α-amino acid substitution with ureido residues to design long lasting peptides.

Antibiotic prophylaxis for external ventricular drains in neurosurgical patients: an audit of compliance with a clinical management protocol

OBJECTIVE

To examine the clinical impact of a management protocol for external ventricular drains (EVD).

PATIENTS AND METHODS

All patients with EVDs over a six-month period were reviewed retrospectively. Data concerning the indications for EVD placement, antibiotics and cerebrospinal fluid (CSF) analyses were collected. A restrictive antibiotic protocol (e.g. intravenous cephalothin 1g 6-hourly for 24 hours, unless other antibiotics were prescribed for a documented pre-existing infection) was introduced for all patients requiring placement of an EVD during the following six months and all patients were observed prospectively. Daily CSF samples were collected under sterile conditions and examined for organisms, cells, glucose and protein and sent for microbiological culture. External ventricular drains were removed after five days and replaced if further monitoring or CSF drainage was required. Adherence to the protocol and the incidence of ventriculitis was determined.

RESULTS

Twelve patients with EVDs were identified during the 6 month pre-protocol period and 15 patients with EVDs were identified during the 6 month post-protocol period. There was no significant difference between the total (72 vs 88 days) and mean (6 vs 5.9 days) drain placement times between the two groups. There was no significant difference between the mean numbers of CSF samples in the two groups. CSF aspirates were not analysed in 35/72 samples (49%) in the pre-protocol group compared with 45/88 (51%) samples in the post-protocol group. Positive CSF Gram-stains were found in 3/12 (25%) patients in the pre-protocol group and in 0/15(0%) in the post-protocol group. Positive CSF cultures decreased significantly in the post-protocol group (17 vs 5, p = 0.0009). Prophylactic antibiotics were prescribed in 5/12 (42%) patients in the pre-protocol group compared with 12/15 (80%) patients in the post-protocol group.

CONCLUSIONS

The protocol was associated with a statistically significant improvement in compliance with antibiotic prescription and reduction in the incidence of positive CSF cultures.

Recombinant activated factor VII for exsanguinating haemorrhage post bilateral lung transplantation for extra-corporeal lung support-dependent respiratory failure

Following three weeks of extracorporeal lung support for acute respiratory distress syndrome, a 15-year-old male underwent bilateral lung transplantation. This procedure was complicated by massive postoperative haemorrhage. The administration of recombinant activated Factor VII was associated with improved haemostasis. However, development of cardiac tamponade soon after injection required emergency exploration and evacuation of a large mediastinal clot.

Does neostigmine increase gastric emptying in the critically ill?--results of a pilot study

OBJECTIVE

Based on the successful use of neostigmine for the treatment of acute colonic pseudo-obstruction, we hypothesised that neostigmine would increase gastric emptying and improve tolerance to enteral feeding in the critically ill patient.

METHODS

Eleven patients intolerant of enteral feeds due to high gastric aspirates, were randomised to receive a 'study infusion' consisting of either neostigmine (0.4 mg/hr) or 0.9% saline. If, after 12 hours the patient was deemed intolerant of the nasogastric feed, the rate of the 'study infusion' was doubled. Those who remained intolerant after 24 hours of the 'study infusion' were 'crossed-over' and continued on the other infusion for a further 24 hours. Gastric emptying was assessed in each group before and after the infusion by measuring the hourly rates of feed "absorption" [(delivery rate + returned aspirates) - total aspirates] and paracetamol absorption using the area under a time-concentration curve at 120 minutes (AUC120). Differences within and between groups were analysed using Students t test and one-way analysis of variance.

RESULTS

Six patients received neostigmine first and 5 received the placebo first. Four of the 6 patients receiving the neostigmine first compared with all of those receiving placebo first required to be 'crossed-over' to the other infusion. While the hourly rates of feed "absorption" were greater for patients receiving neostigmine than for placebo, these differences did not achieve statistical significance. The mean paracetamol AUC120 for all patients who received neostigmine was 3996 mg/min/L while that for placebo was 1929 mg/min/L (p = 0.21).

CONCLUSIONS

These data suggest that while neostigmine may have a positive effect on gastric emptying and enteral feed absorption in critically ill patients, the results did not reach statistical significance and an adequately powered study will be required to confirm this effect.