Alterations in the innate and adaptive immune system in a real-world cohort of multiple sclerosis patients treated with ocrelizumab.

B cell depletion by the anti-CD20 antibody ocrelizumab is effective in relapsing-remitting (RR) and primary progressive (PP) multiple sclerosis (MS). We investigated immunological changes in peripheral blood of a real-world MS cohort after 6 and 12 months of ocrelizumab. All RRMS and most PPMS patients (15/20) showed treatment response. Ocrelizumab not only reduced CD20+ B cells, but also numbers of CD20+ T cells. Absolute numbers of monocytes, dendritic cells and CD8+ T cells were increased, while CD56hi natural killer cells were reduced after ocrelizumab. The residual B cell population shifted towards transitional and activated, IgA+ switched memory B cells, double negative B cells, and antibody-secreting cells. Delaying the treatment interval by 2-3 months increased mean B cell frequencies and enhanced naive B cell repopulation. Ocrelizumab reduced plasma levels of interleukin(IL)-12p70 and interferon(IFN)-α2. These findings will contribute to understanding ineffective treatment responses, dealing with life-threatening infections and further unravelling MS pathogenesis.

Can heart rate variability parameters derived by a heart rate monitor differentiate between atrial fibrillation and sinus rhythm?

BACKGROUND: Heart rate variability (HRV) parameters, and especially RMSSD (root mean squared successive differences in RR interval), could distinguish atrial fibrillation (AF) from sinus rhythm(SR) in horses, as was demonstrated in a previous study. If heart rate monitors (HRM) automatically calculating RMSSD could also distinguish AF from SR, they would be useful for the monitoring of AF recurrence. The objective of the study was to assess whether RMSSD values obtained from a HRM can differentiate AF from SR in horses. Furthermore, the impact of artifact correction algorithms, integrated in the analyses software for HRV analyses was evaluated. Fourteen horses presented for AF treatment were simultaneously equipped with a HRM and an electrocardiogram (ECG). A two-minute recording at rest, walk and trot, before and after cardioversion, was obtained. RR intervals used were those determined automatically by the HRM and by the equine ECG analysis software, and those obtained after manual correction of QRS detection within the ECG software. RMSSD was calculated by the HRM software and by dedicated HRV software, using six different artifact filters. Statistical analysis was performed using the Wilcoxon signed-rank test and receiver operating curves. RESULTS: The HRM, which applies a low level filter, produced high area under the curve (AUC) (> 0.9) and cut off values with high sensitivity and specificity. Similar results were obtained for the ECG, when low level artifact filtering was applied. When no artifact correction was used during trotting, an important decrease in AUC (0.75) occurred. CONCLUSION: In horses treated for AF, HRMs with automatic RMSSD calculations distinguish between AF and SR. Such devices might be a useful aid to monitor for AF recurrence in horses.

Pharmacokinetics and electrophysiological effects of sotalol hydrochloride in horses.

BACKGROUND: Arrhythmias in horses may require long-term anti-arrhythmic therapy. Unfortunately, oral anti-arrhythmic drugs for use in horses are currently scarce. In human patients and small animals, sotalol, a ß-blocker with class III anti-arrhythmic properties, is often used for long-term treatment. OBJECTIVES: To determine the pharmacokinetics of sotalol at multiple oral dosages in unfasted horses, as well as the effects on electro- and echocardiographic measurements, right atrial and ventricular monophasic action potential (MAP) and effective refractory period (ERP). STUDY DESIGN: Placebo controlled, double-blinded experiment. MATERIALS AND METHODS: Six healthy, unfasted Warmblood horses were given either 0, 2, 3 or 4 mg/kg bodyweight (bwt) sotalol orally (PO) twice daily (bid) for 9 days in a randomised cross-over design. Echocardiography and surface electrocardiography were performed and plasma concentrations of sotalol and right atrial and right ventricular MAPs and ERPs were determined at steady-state conditions. Statistical analysis was performed using a repeated measures univariate analysis with post hoc Bonferroni corrections. RESULTS: Calculated mean steady-state plasma concentrations determined by nonlinear mixed-effect modelling were 287 (range 234-339), 409 (359-458) and 543 (439-646) ng/mL for 2, 3 and 4 mg/kg bwt sotalol PO bid respectively. Sotalol significantly increased the QT interval and ERPs, but, despite increasing plasma concentrations, higher dosages did not result in a progressive increase in QT interval or ERPs. Echocardiographic and other electrocardiographic measurements did not change significantly. MAP durations at 90% repolarisation were not significantly different during sotalol treatment. Besides transient local sweating, no side effects were noted. MAIN LIMITATIONS: Study size and ad libitum feeding of hay. CONCLUSIONS: Sotalol at a dose of 2, 3 and 4 mg/kg bwt PO bid increases the QT interval and ERP and might be a useful drug for long-term anti-arrhythmic therapy in horses.

Heart rate variability parameters in horses distinguish atrial fibrillation from sinus rhythm before and after successful electrical cardioversion.

BACKGROUND: Atrial fibrillation (AF) is the most common pathological arrhythmia in horses. After successful treatment, recurrence is common. Heart rate monitors are easily applicable in horses and some devices offer basic heart rate variability (HRV) calculations. If HRV can be used to distinguish between AF and sinus rhythm (SR), this could become a monitoring tool for horses at risk for recurrence of AF. OBJECTIVES: The purpose of this study was to assess whether in horses AF (before cardioversion) and SR (after cardioversion) can be differentiated based upon HRV parameters. STUDY DESIGN: Cohort study with internal controls. METHODS: Six HRV parameters were determined in 20 horses, both in AF and in SR, at rest (2- and 5-min and 1- and 4-h recordings) and during exercise (walk and trot, 2-min recordings). Time-domain (standard deviation of the NN intervals, root mean squared successive differences in NN intervals and triangular index), frequency domain (low/high frequency ratio) and nonlinear parameters (standard deviation of the Poincaré plot [SD]1 and SD2) were used. Statistical analysis was done using paired Wilcoxon signed rank tests and receiver operating characteristic curves. RESULTS: HRV was higher during AF compared to SR. Results for the detection of AF were good (area under the receiver operating characteristic curve [AUC] 0.8-1) for most HRV parameters. Root mean squared successive differences in NN intervals and SD1 yielded the best results (AUC 0.9-1). Sensitivity and specificity were high for all parameters at all recordings, but highest during exercise. Although AUCs improved with longer recordings, short recordings were also good (AUC 0.8-1) for the detection of AF. In horses with frequent second degree atrioventricular block, HRV at rest is increased and recordings at walk or trot are recommended. MAIN LIMITATIONS: Animals served as their own controls and there was no long-term follow-up to identify AF recurrence. CONCLUSIONS: AF (before cardioversion) and SR (after cardioversion) could be distinguished with HRV. This technique has promise as a monitoring tool in horses at risk for AF development.

Echocardiographic measurements of right heart size and function in healthy horses.

REASONS FOR PERFORMING STUDY: Right ventricular (RV) function is scarcely described in horses. OBJECTIVES: To establish reliable echocardiographic measurements of right heart size and function in horses. STUDY DESIGN: Descriptive study in healthy horses. METHODS: Ten healthy untrained adult trotter horses underwent repeated echocardiography performed by 2 sonographers from right and left parasternal standard and nonstandard views. Nonstandard views included a right parasternal view focused on the right atrium, left parasternal long-axis pulmonary artery view, left parasternal long-axis view focused on the right ventricle including anatomical M-mode of tricuspid annular motion and left parasternal pulsed wave Doppler recording of pulmonary flow. During off-line analysis, 2 observers performed two-dimensional, M-mode, pulsed wave Doppler, tissue Doppler imaging (TDI) and two-dimensional speckle tracking (2DST) measurements of RV size and function. Acquisition and measurement variability were assessed by calculating coefficients of variation (CV) from one-way repeated measures analyses of variance. The degree of variability was classified as low (CV<15%), moderate (CV 15-25%) or high (CV>25%). RESULTS: Most two-dimensional and M-mode measurements of RV, right atrial and pulmonary artery size showed low variability. The two-dimensional, M-mode and pulsed wave Doppler measurements of RV function showed a low to moderate variability. Right ventricular functional measurements by 2DST showed low variability, except for segmental strain rate. Right ventricular functional measurements by TDI showed a low to high variability, with a lower variability for timing than for peak measurements and a lower variability for velocity compared with deformation measurements. CONCLUSIONS: Right heart size and function can be assessed with low variability in horses.

Atrial Premature Depolarization-Induced Changes in QRS and T Wave Morphology on Resting Electrocardiograms in Horses.

BACKGROUND: The electrocardiographic differentiation between atrial (APDs) and ventricular (VPDs) premature depolarizations is important. P wave prematurity and normal QRS and T wave morphology generally are used as discriminating criteria for APDs. HYPOTHESIS/OBJECTIVES: The aim of this study was to determine whether P, Q, R, S, and T wave amplitude, PQ interval, QRS and P wave duration and P and T wave morphology differ between APDs and sinus beats. To determine the relationship between the RR coupling interval and the change in S wave amplitude between sinus beats and APDs. METHODS: Case-control study. From a modified base-apex configuration of 30 horses with APDs at rest, sinus beat and APD associated preceding RR interval, P, PQ and QRS duration and P, R, S, and T wave amplitudes were measured. Linear mixed models and logistic regression were used to determine the effect of APDs on the ECG variables studied. RESULTS: In comparison to sinus beats, APDs were associated with a significant (P < .001) change in P amplitude (-0.03 ± 0.01 mV) and increase in S (0.20 ± 0.02 mV) and T (0.08 ± 0.03 mV) amplitude. PQ (-20.3 ± 5.2 ms) and RR (-519 ± 14 ms) interval and P duration (-21.1 ± 3.0 ms) decreased (P < .001). APDs were significantly associated with a singular positive P wave (OR: 11.0, P < .001) and were more likely to have a monophasic positive T wave (OR: 9.2, P < .001). A smaller RR coupling interval was associated with an increased relative difference in S amplitude (P < .01). CONCLUSIONS: Atrial premature depolarizations may lead to changes in QRS and T wave morphology. Knowledge of these changes is important to avoid interpreting certain APDs as VPDs.

Pharmacokinetics of intravenously and orally administered sotalol hydrochloride in horses and effects on surface electrocardiogram and left ventricular systolic function.

Arrhythmias are common in horses. Some, such as frequent atrial or ventricular premature beats, may require long-term anti-arrhythmic therapy. In humans and small animals, sotalol hydrochloride (STL) is often used for chronic oral anti-arrhythmic therapy. STL prolongs repolarization and the effective refractory period in all cardiac tissues. No information on STL pharmacokinetics or pharmacodynamics in horses is available and the aim of this study was to evaluate the pharmacokinetics of intravenously (IV) and orally (PO) administered STL and the effects on surface electrocardiogram and left ventricular systolic function. Six healthy horses were given 1 mg STL/kg bodyweight either IV or PO. Blood samples to determine plasma STL concentrations were taken before and at several time points after STL administration. Electrocardiography and echocardiography were performed at different time points before and after IV STL administration. Mean peak plasma concentrations after IV and PO administration of STL were 1624 ng/mL and 317 ng/mL, respectively. The oral bioavailability was intermediate (48%) with maximal absorption after 0.94 h, a moderate distribution and a mean elimination half-life of 15.24 h. After IV administration, there was a significant increase in QT interval, but no significant changes in other electrocardiographic and echocardiographic parameters. Transient transpiration was observed after IV administration, but no adverse effects were noted after a single oral dose of 1 mg/kg STL in any of the horses. It was concluded that STL has an intermediate oral bioavailability in the horse and might be useful in the treatment of equine arrhythmias.

Clinical Research Abstracts of the British Equine Veterinary Association Congress 2015.

REASONS FOR PERFORMING THE STUDY: Yellow fat disease or steatitis is characterised by a local or general inflammation of fat tissue and is occasionally found in horses. Diagnosis is challenging because of the wide range of nonspecific clinical signs. OBJECTIVES: To describe clinical signs, treatment, outcome and ultrasonographic findings in horses with steatitis. STUDY DESIGN: Retrospective study (January 2008 to January 2015). METHODS: History, clinical signs, ultrasonographic findings, diagnosis, treatment and outcome were recorded. RESULTS: Twenty cases (18 horses, 2 donkeys; 9 mares, 9 stallions, 2 geldings) were retrieved from 13,707 patient records. Mean age was 1.6 (± 0.8) years (range 1 month-3.5 years). All cases appeared between October and February except for one (August). History included dullness, recumbency, decreased appetite and weight loss. Fever, ventral oedema, stiff/painful gait and painful neck were found. Low haematocrit, low vitamin E and selenium and increased levels of creatinine kinase and particularly lactate dehydrogenase were almost consistent findings. On ultrasound, ventral oedema was found. Subperitoneal, perirenal, mesenteric, coronary and caudal mediastinal fat showed homogenously increased echogenicity. Especially the subperitoneal fat was surrounded by oedema or free fluid. Increased amounts of abdominal, thoracic and pericardial fluid were often found. Fat biopsies were taken in the neck or from the retroperitoneal fat in the ventral flank. In all horses where fat biopsy was taken (n = 13), steatitis was confirmed. Treatment consisted of selenium and vitamin E (intra-muscular injection followed by oral treatment) supplementation and anti-inflammatory treatment (dexamethasone or prednisolone parenteral or oral) for at least 1-4 weeks. Fourteen animals (70%) survived. Full recovery took about 2-6 months. CONCLUSIONS: Yellow fat disease may be underdiagnosed because of the nonspecific clinical signs. Ultrasound was extremely helpful for making a diagnosis. Recovery was rather slow but was achieved in 70% of the animals. Ethical animal research: Research ethics committee oversight not currently required by this conference: retrospective study of clinical records. Explicit owner informed consent for inclusion of animals in this study was not stated. SOURCE OF FUNDING: Ghent University (institutional). Competing interests: None declared.

The influence of interleukin-7 receptor α-chain haplotypes on outcome after allogeneic hematopoietic cell transplantation.

We investigated the influence of IL-7 receptor α-chain (IL-7Rα) gene haplotypes in donors on the outcome of haematopoietic cell transplantation (HCT). Unlike the association between single donor SNPs and HCT outcome found previously, only trends towards association were found here, due to 'dilution' of SNPs into haplotypes.

The use of ruminant models in biomedical perinatal research.

Animal models are of critical importance in biomedical research. Although rodents and lagomorphs are the most commonly used species, larger species are required, especially when surgical approaches or new medical devices have to be evaluated. In particular, in the field of perinatal medicine, they are critical for the evaluation of new pharmacologic treatments and the development of new invasive procedures in fetuses. In some areas, such as developmental genetics, reproductive biotechnologies and metabolic programming, the contribution of ruminants is essential. The current report focuses on some of the most outstanding examples of great biomedical advances carried out with ruminant models in the field of perinatal research. Experiments recently carried in our research unit using ruminants are also briefly described.

Short-term effects of maternal feed restriction during pregnancy on goat kid morphology, metabolism, and behavior.

Morphometric, metabolic, and behavioral modifications were studied in goat kids after maternal feed restriction during the last one-third of pregnancy. At birth, only kids from twin and triplet litters were studied [n=40 kids born to control dams (CONT) and n=38 born to restricted dams (REST)] and only males thereafter (n=13 CONT and 15 REST kids) until slaughter at 6 wk of age. Kids born to restricted goats had a smaller abdominal girth at birth (P<0.01) and tended to have a smaller body mass index (P=0.10) and a smaller density index (P=0.09) than kids born to CONT goats. Male REST kids had a lighter birth weight (P=0.03) than male CONT kids, but no differences (all P>0.10) were found for BW and morphometric measurements thereafter. Decreased NEFA concentrations suggested that male REST kids mobilized their body reserves less than CONT kids at birth (P<0.01). No modifications in drinking tests at 3 and 5 wk of age were observed, or in feeding behavior and emotional reactivity at 5 wk of age (all P>0.10). In conclusion, maternal feed restriction in the last one-third of pregnancy resulted in a decrease in birth size, but male kids rapidly caught up, and there were no changes in behavior, morphology, or metabolism during rearing.

Haplotype 4 of the multiple sclerosis-associated interleukin-7 receptor alpha gene influences the frequency of recent thymic emigrants.

The receptor for the homeostatic T cell cytokine interleukin-7 (IL-7Ralpha) has recently shown genetic association to multiple sclerosis (MS). To investigate the functional contribution of IL-7Ralpha polymorphisms to the pathogenesis of MS, we correlated the IL-7Ralpha haplotypes with different T cell parameters in a group of MS patients and healthy controls. We show that carriers of one of the four IL-7Ralpha haplotypes (Hap4) show a higher expression of IL-7Ralpha (CD127) on their CD4(+) T cells, compared with noncarriers (P=0.04). Moreover, Hap4 carriers possess higher frequencies of recent thymic emigrants (RTEs, CD31(+)) in both the regulatory T cell (Treg; P=0.007) and conventional T cell (Tconv) population (P=0.0001). This effect is most pronounced within the MS population (Treg, P=0.0077; Tconv, P=0.0007), whereas in healthy controls significance was only reached for Tconv (P=0.043; Treg, P=0.11). Because previous studies showed a decreased RTE-Treg frequency in MS patients compared to healthy subjects, we here conclude that this decrease is localized within the MS population of non-Hap4 carriers. In conclusion, our findings suggest that IL-7Ralpha polymorphisms can influence T cell development and homeostasis, and thereby contribute to the altered immune regulation associated with disease development in patients with MS.