Systemic delivery of human GlyR IgG antibody induces GlyR internalization into motor neurons of brainstem and spinal cord with motor dysfunction in mice

Aims

Progressive encephalomyelitis with rigidity and myoclonus (PERM) is a life‐threatening condition often associated with highly raised serum antibodies to glycine receptors (GlyRs); these bind to the surface of large neurons and interneurons in rodent brain and spinal cord sections and, in vitro, inhibit function and reduce surface expression of the GlyRs. The effects in vivo have not been reported.

Methods

Purified plasma IgG from a GlyR antibody‐positive patient with PERM, and a healthy control (HC), was injected daily into the peritoneal cavity of mice for 12 days; lipopolysaccharide (LPS) to open the blood–brain barrier, was injected on days 3 and 8. Based on preliminary data, behavioural tests were only performed 48 h post‐LPS on days 5–7 and 10–12.

Results

The GlyR IgG injected mice showed impaired ability on the rotarod from days 5 to 10 but this normalized by day 12. There were no other behavioural differences but, at termination (d13), the GlyR IgG‐injected mice had IgG deposits on the neurons that express GlyRs in the brainstem and spinal cord. The IgG was not only on the surface but also inside these large GlyR expressing neurons, which continued to express surface GlyR.

Conclusions

Despite the partial clinical phenotype, not uncommon in passive transfer studies, the results suggest that the antibodies had accessed the GlyRs in relevant brain regions, led to antibody‐mediated internalization and increased GlyR synthesis, compatible with the temporary loss of function.

AB0309 MEASURING THE DIFFERENCE: COMPARISON OF MEASUREMENT OF FREE INFLIXIMAB ANTI-DRUG ANTIBODIES

Background:

Infliximab (IFX) was one of the first TNF alpha inhibitors to be licenced in inflammatory arthritis and is still commonly used today. Studies have shown that approximately 50% of primary IFX responders will suffer from secondary loss of response within the first 12 months of treatment (1). The development of Anti-Drug Antibodies (ADA’s) plays a significant role in this treatment failure (2).

Monitoring of ADA’s helps identify those patients who fail to respond to treatment due to low IFX trough levels. In this scenario the presence of ADA’s can aid decision-making regarding increasing IFX dosing or switching biologic therapy to optimise treatment. (3).

Objectives:

Despite their potential importance the detection of ADAs varies widely depending on the type of assays used. The aim of this study was to determine the qualitative concordance of three commercially available ELISA kits for measurement of free ADAs to IFX on the Grifols Triturus analyser.

Methods:

150 patient samples from patients with inflammatory conditions and low IFX trough drug levels (≤0.6µg/ml) were analysed for free ADAs using Promonitor, Lisa Tracker and IDKmonitor kits on the Grifols Triturus automated ELISA analyser.

Results:

Kappa coefficient (κ) analysis indicated a moderate agreement between the Promonitor and IDKmonitor assays (κ =0.484 (95% CI, 0.357 to 0.611)) and the IDKmonitor and Lisa Tracker assays (κ = 0.485 (95% CI, 0.348-0.621)) as well as substantial agreement between the Promonitor and Lisa Tracker assays (κ =0.768 (95% CI, 0.667-0.870)). Figure 1 shows the distribution of samples identified as free ADA positive by each kit.

Figure 1.

Distribution of samples identified as free ADA positive by Promonitor, Lisa Tracker, and IDKmonitor assays. Fifty samples were considered positive by all assays. Three samples were considered positive by Promonitor and Lisa Tracker, and eight samples were considered positive by Lisa Tracker and IDKmonitor. No samples were considered positive by Promonitor and IDKmonitor. One sample was considered positive by Promonitor only, seven samples were considered positive by Lisa Tracker only, and twenty-six samples were considered positive by IDKmonitor

Conclusion:

All kits appear amenable for utilisation in a high-throughput laboratory though a true quantitative comparison between these kits was precluded by the absence of any certified reference material for free ADAs to IFX.

Although broad qualitative agreement was found between the three kits, they should not be used interchangeably for patient management.

Further research is required to estimate the impact of free ADAs on efficiency of IFX treatment and patient management.

References:

[1]Quistrebert J, Hässler S, Bachelet D et al.Incidence and risk factors for adalimumab and infliximab anti-drug antibodies in rheumatoid arthritis: A European retrospective multicohort analysis. Seminars in Arthritis and Rheumatism Volume 48, Issue 6, June 2019, Pages 967-975 2.

[2]Moots RJ, Xavier RM, Mok CC, Rahman MU, Tsai W-C, Al-Maini MH, et al. (2017)The impact of anti-drug antibodies on drug concentrations and clinical outcomes in rheumatoid arthritis patients treated with adalimumab, etanercept, or infliximab: Results from a multinational, real-world clinical practice, non-interventional study. PLoS ONE 12(4): e0175207.https://doi.org/10.1371/journal.pone.0175207

[3]Smolen JS, Landewé R, Bijlsma J, et al.EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs:2016 update.Annals of the Rheumatic Diseases 2017;76:960-977.

Disclosure of Interests:

Rhona Hamilton: None declared, Stephanie Shields: None declared, Andrew McGucken: None declared, Jonathan MacDonald: None declared, Martin Perry Grant/research support from: Grifols, Abbvie, Sandoz unrestricted educational grant, Consultant of: Abbvie, Gilead, Celltrion Advisory Board, Speakers bureau: Sandoz, Allan Dunlop: None declared, Elaine Gribben: None declared, Peter Galloway: None declared

Comparative efficacy of intranasal and oral vaccines against Bordetella bronchiseptica in dogs

In order to determine the comparative efficacy of vaccines administered intranasally or orally to protect puppies from disease subsequent to experimental infection with Bordetella bronchiseptica (Bb), a randomized controlled trial was performed using 48 approximately 8-week-old specific pathogen free, Bb naive Beagle puppies. Puppies were randomized into three groups and administered vaccines containing Bb intranasally or orally, or a placebo intranasally. Twenty-one days later, all dogs were challenge exposed via aerosol administration of Bb. Clinical signs, nasal bacterial shedding and immune responses were monitored for 28 days after challenge. Intranasally vaccinated puppies had significantly lower rates of coughing, nasal discharge, retching and sneezing (i.e. were less sick clinically) than control puppies. The distinction between the orally vaccinated puppies and the control puppies was less consistent. The orally vaccinated puppies had less coughing and less retching than the control puppies, but nasal discharge and sneezing did not differ from control animals. Orally vaccinated puppies had higher rates of coughing, nasal discharge, retching and sneezing than the intranasally vaccinated puppies. Although both intranasal and oral Bb vaccines stimulated immune responses associated with disease sparing following Bb infection, the intranasal route of delivery conferred superior clinical outcomes. The observed difference in clinical efficacy suggests the need to question the rationale for the use of currently available orally administered Bb vaccines.

Efficiency of use of metabolizable energy for body weight gain in pasture-based, nonlactating dairy cows

Four cohorts of nonlactating, pregnant dairy cows (n=50, 47, 45, and 42) were individually fed indoors to determine the amount of feed required for body weight (BW) gain from autumn pasture and commonly used supplementary feeds. These results were used to estimate the apparent efficiency with which metabolizable energy (ME) is used for BW gain (app_kg). Control cows were offered autumn pasture to estimated maintenance requirements (~0.55 MJ of ME/kg of BW(0.75)), with an additional 20 MJ of ME/d allocated for pregnancy and activity. All other cows received the same allowance of autumn pasture and an additional allowance (2.5 or 5.0 kg of dry matter/d) of autumn pasture (Past), spring pasture silage (Psil), maize silage (Msil), cracked maize grain (Mgr), or palm kernel expeller (PKE), resulting in a total of 11 treatments. Individual cow dry matter intake was determined daily; BW was recorded once per week for cohorts 1 and 2, and 3 times per week for cohorts 3 and 4. The ME contents of feeds were estimated from feed quality assays. Regression analyses were used on each feed to determine the ME requirement for 1 kg of BW gain. The app_kg of Past and Msil was 0.34 and 0.47, respectively; these estimates are in line with published literature. The app_kg of Psil (0.50) was consistent with the published kg for spring pasture, from which the silage was made. Palm kernel expeller had the greatest app_kg (0.61). The reasons for this cannot be deduced from the current study but may reflect the relatively high fat content of the feed and the high kg of fat. The app_kg for Mgr was low (0.38) in comparison with the other supplementary feeds and, in particular, relative to its feed ME and published kg estimates. Although the reason for the low app_kg cannot be deduced from the current data, the most plausible reason is the preferential use of propionate-derived glucose for conceptus metabolism rather than BW gain, a factor not accounted for in previous experimental models that did not use late-gestation cows. In summary, the app_kg for autumn pasture was low but consistent with historical growth rate trials in other ruminant species. In comparison, Msil, Psil, and PKE were used with a greater apparent efficiency (app_kg=0.47 to 0.61), but Mgr resulted in a relatively low rate of gain per MJ of ME (app_kg=0.38). These differences have implications for accurate feed budgeting on farm.

Endoscopic retrograde cholangiopancreatography after pancreaticoduodenectomy for benign and malignant disease: indications and technical outcomes

BACKGROUND AND STUDY AIMS

Patients undergoing pancreaticoduodenectomy develop postoperative complications related to surgery and their disease. Very little data are available on the role or success of endoscopic retrograde cholangiopancreatography (ERCP) in such patients. The aim of this study was to evaluate the indications and role of diagnostic and therapeutic ERCP after pancreaticoduodenectomy for both benign and malignant disease.

PATIENTS AND METHODS

This study was a 10-year (1990 - 2000) single institution retrospective review of all ERCPs performed on patients who had undergone pancreaticoduodenectomy surgery. Indications for the ERCP and technical procedural success were studied.

RESULTS

29 patients with a pancreaticoduodenectomy underwent 56 ERCPs. Reasons for surgery were neoplasia and chronic pancreatitis. Indications for ERCP included evaluation of jaundice and pain. Technical success related to the clinical indication (jaundice 69 %, pain 54 %).

CONCLUSION

ERCP plays an important role in the management of postpancreatic surgery problems including biliary and anastomotic strictures, and should be the modality of choice. However, surgical technique may make the afferent limb inaccessible, and the ductal anastomosis difficult to identify in patients with some types of pancreaticoduodenectomy. Closer collaboration between surgeon and endoscopist may allow alterations in surgical technique to improve postoperative ERCP success.

Bradykinin and nerve growth factor release the capsaicin receptor from PtdIns(4,5)P2-mediated inhibition

Tissue injury generates endogenous factors that heighten our sense of pain by increasing the response of sensory nerve endings to noxious stimuli. Bradykinin and nerve growth factor (NGF) are two such pro-algesic agents that activate G-protein-coupled (BK2) and tyrosine kinase (TrkA) receptors, respectively, to stimulate phospholipase C (PLC) signalling pathways in primary afferent neurons. How these actions produce sensitization to physical or chemical stimuli has not been elucidated at the molecular level. Here, we show that bradykinin- or NGF-mediated potentiation of thermal sensitivity in vivo requires expression of VR1, a heat-activated ion channel on sensory neurons. Diminution of plasma membrane phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) levels through antibody sequestration or PLC-mediated hydrolysis mimics the potentiating effects of bradykinin or NGF at the cellular level. Moreover, recruitment of PLC-gamma to TrkA is essential for NGF-mediated potentiation of channel activity, and biochemical studies suggest that VR1 associates with this complex. These studies delineate a biochemical mechanism through which bradykinin and NGF produce hypersensitivity and might explain how the activation of PLC signalling systems regulates other members of the TRP channel family.

A comparison of patients' responses about their disability with and without attribution to their affected area

The purpose of this study was to determine whether individual items in a disability questionnaire were answered differently depending on whether or not the questions were attributed to the upper limb (i.e., "do you have difficulty eating due to your arm or hand problem?" or "do you have difficulty eating?", respectively). The a priori hypothesis was that the same or more disability would be detected by nonattributed items. Four hundred sixty-seven patients with upper extremity disorders completed the SF-36 general health survey, which does not attribute health problems to affected areas. Patients also completed six additional questions, modified from the SF-36, regarding work (four questions) and social function with friends and family (two questions), which attributed their disability to their affected upper extremity. Of 467 patients, 419-431 (89-92%) responded to both versions of the questions. Although we demonstrated a significant order effect (Generalized Estimating Equation; P=.003), comparison of the responses to the six questions showed that for five of the six questions (Generalized Estimating Equation; P< or = .001) patients reported more disability when the questions were worded with attribution to the upper extremity. Even considering the order effect, patients demonstrated a counterintuitive result by reporting more disability when questions were attributed to their affected area. Thus, both the wording of questions and order of questions can significantly affect patients' responses about their disability and raises questions about the validity of patients' reports of their disability.

Group I metabotropic glutamate antagonist reduces acute neuronal degeneration and behavioral deficits after traumatic brain injury in rats

Recent studies indicate that acute activation of Group I mGluRs following traumatic brain injury (TBI) contributes to the ensuing pathophysiology. The present study examined the effects of post-TBI administration of the selective mGluR1 antagonist (RS)-1-aminoindan-1,5-dicarboxylic acid (AIDA) on acute neuronal degeneration in the hippocampus and long-term sensorimotor and learning/memory outcome. In Experiment 1, 26 rats received 0.4, 2.0, or 10.0 nmol AIDA or artificial CSF vehicle infusion into the hippocampus starting 5 min postinjury. At 24 h after TBI characteristic pyramidal cell degeneration was observed in Fluoro-Jade-stained coronal sections of the CA2/3 sectors of the dorsal hippocampus. The mean (+/-SEM) number of Fluoro-Jade-positive neurons in the 10 nmol AIDA group (184 +/- 32) was significantly less (P < 0.05) than the vehicle group (310 +/- 47). In Experiment 2, 20 rats were trained on sensorimotor and memory tasks prior to parasagittal fluid percussion TBI. Rats were administered 10 nmol AIDA or vehicle as in Experiment 1. Rats were assessed on beam walking and radial arm maze (RAM) performance weekly for 6 weeks after TBI. Acquisition of a Morris water maze (MWM) task was assessed on days 11-15 after TBI. The AIDA-treated group had significantly reduced deficits in beam walk, MWM, and RAM performance compared to the vehicle-treated group. These data indicate that injury-induced acute activation of mGluR1 receptors contributes to both the cellular pathology and the behavioral morbidity associated with TBI.

Remyelination occurs as extensively but more slowly in old rats compared to young rats following fliotoxin-induced CNS demyelination

Shields SA, Gilson JM, Blakemore W, Franklin RJ. 1999. Remyelination occurs as extensively but more slowly in old rats compared to young rats following fliotoxin-induced CNS demyelination. Glia 28:77-83. The article referenced above was published as a Short Communication instead of an Original Article. The publisher regrets this error.

Reliability of isometric wrist extension torque using the LIDO WorkSET for late follow-up of postoperative wrist patients

The objectives of this study were to determine interobserver, intraobserver, and overall reliability of isometric wrist extension torque using the LIDO WorkSET and then to estimate the minimal level of detectable change using the standard error of measurement. A generalizability study was conducted on 18 postoperative patients. Primary outcome was mean torque of three trials. Variance components were used to calculate generalizability coefficients for intraobserver (G = 0.96), interobserver (G = 0.94), and overall reliability (G = 0.92). When the same therapist is evaluating a patient on different days, a change of more than 16 inch-lb is needed to be 90% confident that true change has occurred. A greater value for change (23 inch-lb) is required when different therapists evaluate a patient on different days. The LIDO WorkSET measures wrist torque in a reproducible manner in an applied setting. The testing protocol is sensitive to differences in wrist torque between individuals and tolerated in the late postoperative period.

The role of ultrasound in the management of retinopathy of prematurity

The authors reviewed the ultrasonic appearance of 54 eyes (27 patients) with advanced retinopathy of prematurity (ROP) and compared the various retinal configurations with the findings at surgery. They found that ultrasound is a sensitive indicator of retinal configuration (type and degree of retinal detachment [RD]), as well as showing the existence of subretinal or choroidal hemorrhage often present in these severely affected eyes. Ultrasound is a useful modality to evaluate, document, and follow the progression of RD in ROP.

Transpupillary argon laser cyclophotocoagulation in the treatment of glaucoma

Twenty-seven patients with glaucoma, which could not be controlled with maximum tolerable medication and standard laser techniques, underwent transpupillary argon laser cyclophotocoagulation. Only six patients (22.3%) had a successful outcome, and the postoperative course in many cases was complicated by an additional, sustained increase in intraocular pressure. Notwithstanding these results, the procedure may be useful occasionally to preclude the need for conventional glaucoma surgery.

Developmental changes in calmodulin-kinase II activity at brain synaptic junctions: alterations in holoenzyme composition

Synaptic junctions (SJs) from rat forebrain were isolated at increasing postnatal ages and examined for endogenous protein kinase activities. Our studies focused on the postnatal maturation of the multifunctional protein kinase designated Ca2+/calmodulin-dependent protein kinase II (CaM-kinase II). This kinase is comprised of a major 50-kilodalton (kDa) and a minor 60-kDa subunit. Experiments examined the developmental properties of CaM-kinase II associated with synaptic plasma membranes (SPMs) and synaptic junctions (SJs), as well as the holoenzyme purified from cytosolic extracts. Large developmental increases in CaM-kinase II activity of SJ fractions were observed between postnatal days 6 and 20; developmental changes were examined for a number of properties including (a) autophosphorylation, (b) endogenous substrate phosphorylation, (c) exogenous substrate phosphorylation, and (d) immunoreactivity. Results demonstrated that forebrain CaM-kinase II undergoes a striking age-dependent change in subunit composition. In early postnatal forebrain the 60-kDa subunit constitutes the major catalytic and immunoreactive subunit of the holoenzyme. The major peak of CaM-kinase II activity in SJ fractions occurred at approximately postnatal day 20, a time near the end of the most active period of in vivo synapse formation. Following this developmental age, CaM-kinase II continued to accumulate at SJs; however, its activity was not as highly activated by Ca2+ plus calmodulin.

Comparison of Helium Leak Test and Vacuum Leak Test Using Canned Foods: Collaborative Study

Two can leak tests were compared by 7 collaborators. In the helium leak test, pressurized helium is applied to the outside of the container, and a headspace gas sample from the can is then analyzed for the presence of helium. The vacuum test is described in the Bacteriological Analytical Manual. Ninety No. 303 cans of creamed-style corn, green beans, carrots, fruit cocktail, and whole-kernel corn were shipped in 3 groups. Two groups of 30 cans had 10 dented flat cans, 5 flat controls (nondented), 10 dented swollen cans, and 5 swollen control cans (nondented). The third group had 10 dented swollen cans and 5 swollen control cans. Of 600 cans analyzed, 37 (6.2%) were deleted from the analysis because results were not available for both tests. One laboratory was constrained by scheduling to analyze 15 of 45 swollen cans. The helium leak test found 12 (13%) positives of 92 nondented swollen cans. One pressurization test yielded 7 of those 12 positives. Of the 400 dented cans sent as possible leakers, the helium test found 267 positives, and the vacuum test found 181. Five of the 7 analysts had significantly (α = 0.05) higher percent positive helium results. One analyst found more leakers by the vacuum leak test. Both tests found fewer positives in the swollen dented cans than in the flat dented cans. After exposure to pressurized helium, all cans with greater than 8 psi headspace pressure were positive helium leakers. The method was adopted official first action.

Reversibility of hepatic failure following jejunoileal bypass

Jejunoileal bypass was performed in 50 morbidly obeses patients. The morbidity encountered compared favorably with that of other series. All patients manifesting hepatic failure demonstrated hyperbilirubinemia within the first three months postoperatively. Hyperbilirubinemia, if uncorrected, resulted in a mortality of 75%. Augmentation jejunal interposition was performed in three patients who demonstrated hepatic decompensation or severe electrolyte imbalance or both. This resulted in rapid correction of electrolyte disturbances, liver function measurements, and patient symptoms without significant postoperative weight gain. Persistent hyperbilirubinemia or recalcitrant electrolyte problems or both are indications for augmentation jejunal interposition.