Polyamine metabolism impacts T cell dysfunction in the oral mucosa of people living with HIV

Metabolic changes in immune cells contribute to both physiological and pathophysiological outcomes of immune reactions. Here, by comparing protein expression, transcriptome, and salivary metabolome profiles of uninfected and HIV+ individuals, we found perturbations of polyamine metabolism in the oral mucosa of HIV+ patients. Mechanistic studies using an in vitro human tonsil organoid infection model revealed that HIV infection of T cells also resulted in increased polyamine synthesis, which was dependent on the activities of caspase-1, IL-1β, and ornithine decarboxylase-1. HIV-1 also led to a heightened expression of polyamine synthesis intermediates including ornithine decarboxylase-1 as well as an elevated dysfunctional regulatory T cell (T_regDys)/T helper 17 (Th17) cell ratios. Blockade of caspase-1 and polyamine synthesis intermediates reversed the T_regDys phenotype showing the direct role of polyamine pathway in altering T cell functions during HIV-1 infection. Lastly, oral mucosal T_regDys/Th17 ratios and CD4 hyperactivation positively correlated with salivary putrescine levels, which were found to be elevated in the saliva of HIV+ patients. Thus, by revealing the role of aberrantly increased polyamine synthesis during HIV infection, our study unveils a mechanism by which chronic viral infections could drive distinct T cell effector programs and T_reg dysfunction.

Microbial dysbiosis in a mouse model of atopic dermatitis mimics shifts in human microbiome and correlates with the key pro-inflammatory cytokines IL-4, IL-33 and TSLP

BACKGROUND

Cutaneous bacterial dysbiosis is a characteristic hallmark of atopic dermatitis (AD) and it decisively influences the severity of the disease. Despite this, frequently used murine models of AD have not been characterized regarding the changes in skin microbiome communities.

OBJECTIVE

To analyze the skin microbiome of two frequently used murine models for AD for assessing their applicability in translational research.

METHODS

AD was induced in mice by topical application of calcipotriol, or oxazolone. Following comparable elicitation of AD-like dermatitis, including IgE induction, the skin microbial communities were analyzed and compared with human AD.

RESULTS

We detected critical differences in the microbiota composition of diseased skin. In contrast to calcipotriol treatment, application of oxazolone induced significant changes of the cutaneous microbiota and a drastic drop of bacterial richness. Furthermore, an expansion of Staphylococci, particularly S. xylosus was observed in the oxazolone group, also displaying positive correlations with AD key markers including pH, TEWL, IL-4, TSLP and IL-33.

CONCLUSIONS

In this article we show that i) the model of choice to investigate AD needs to be characterized for the cutaneous microbiota if applicable and ii) the oxazolone-mediated mixed Th1-Th2 immune response triggers microbiota-induced alterations which share similarities to dysbiosis in human AD and represents therefore a suitable model for translational research on AD if alterations of the microbiome are in the focus of the investigation.

EU-OSHÁs perspective on occupational safety and health in the Covid-19 pandemic

In July 2020, EU-OSHA published the results of a comprehensive research project on the exposure of workers to biological agents at work and the related health problems. Although the research was initiated long before the pandemic, researchers had highlighted pandemic preparedness as an issue, as well as the general lack of monitoring of serious infectious diseases. The research also made evident a lack of awareness among workplace actors of the risks from exposure to biological agents at work, although a detailed legislative framework has been in place for many years, and consequently a lack of prevention measures at work, which became evident after the pandemic broke out. It highlighted the need for public health and occupational safety and health organisations to cooperate to mitigate the impact of the pandemic. The presentation will focus on the links between the research findings and the developments during the pandemic. It will furthermore present guidance produced by EU-OSHA and other relevant actions, with a view on the legislation that is in place. It will cover biological agents exposure as well as telework and ergonomic issues arising from it.

Oral immune dysfunction is associated with the expansion of FOXP3+PD-1+Amphiregulin+ T cells during HIV infection

Residual systemic inflammation and mucosal immune dysfunction persist in people living with HIV, despite treatment with combined anti-retroviral therapy, but the underlying immune mechanisms are poorly understood. Here we report that the altered immune landscape of the oral mucosa of HIV-positive patients on therapy involves increased TLR and inflammasome signaling, localized CD4+ T cell hyperactivation, and, counterintuitively, enrichment of FOXP3+ T cells. HIV infection of oral tonsil cultures in vitro causes an increase in FOXP3+ T cells expressing PD-1, IFN-γ, Amphiregulin and IL-10. These cells persist even in the presence of anti-retroviral drugs, and further expand when stimulated by TLR2 ligands and IL-1β. Mechanistically, IL-1β upregulates PD-1 expression via AKT signaling, and PD-1 stabilizes FOXP3 and Amphiregulin through a mechanism involving asparaginyl endopeptidase, resulting in FOXP3+ cells that are incapable of suppressing CD4+ T cells in vitro. The FOXP3+ T cells that are abundant in HIV-positive patients are phenotypically similar to the in vitro cultured, HIV-responsive FOXP3+ T cells, and their presence strongly correlates with CD4+ T cell hyper-activation. This suggests that FOXP3+ T cell dysregulation might play a role in the mucosal immune dysfunction of HIV patients on therapy.

Nuclear heterogeneity is prevalent in high-quality fractionated human sperm cells typically used for assisted conception

STUDY QUESTION

What is the nuclear heterogeneity of high-density purified human spermatozoa typically used for IVF purposes.

SUMMARY ANSWER

The data show that while density gradient separation has improved the overall sperm population, there is still a large degree of nuclear heterogeneity within these cells.

WHAT IS KNOWN ALREADY

Chromomycin A3 (CMA3) is an important DNA binding fluorochrome for the assessment of male-factor fertility. It is typically used to predict IVF outcomes on entire sperm ejaculates with very high receiver operating characteristic. Here we used CMA3 to characterise typical populations of human spermatozoa that would be used for IVF purposes after density gradient separation.

STUDY DESIGN, SIZE, DURATION

We compared the intensity of CMA3 binding within high-dense sperm populations obtained from men. Binding heterogeneity was confirmed through fluorescence microscopy and FACS analysis independently. We also looked at CMA3 staining directly with head morphology in this sperm population. Finally, we looked at electron micrographs of nuclear heterogeneity (vacuoles, chromatin compaction) of spermatozoa following density gradient sorting of CMA3-stained cells.

PARTICIPANTS/MATERIALS, SETTING, METHODS

We used sperm donors who had fathered one or more children. Semen was collected after 2 days abstinence and purified over Percoll gradients. Only the high-quality spermatozoa, the same used for assisted conception, were then used. Cells were stained with CMA3 and sorted using FACS. Following this, electron micrographs were used to assess nuclear heterogeneity of CMA3-dependent sorted spermatozoa.

MAIN RESULTS AND THE ROLE OF CHANCE

CMA3 staining occurs within morphologically normal as well as abnormal spermatozoa. High-intensity CMA3-stained sperm possessed large vacuoles that were not seen in the low-CMA3 population. In addition, the high-CMA3 stained cells possess higher amounts of nuclear granulation.

LIMITATIONS, REASONS FOR CAUTION

The present study only describes the issues within the chromatin of these cells and does not suggest an alternate selection technique.

WIDER IMPLICATIONS OF THE FINDINGS

CMA3 is one of the better reported prognostic assays in predicting pregnancy outcomes, especially in cases where the male is at fault. However, it is clear that even in fractionated populations of human spermatozoa, there are sperm cells that are morphologically normal yet possess high levels of CMA3 staining and chromatin granulation. The implication of this is that the embryologist, whom selects on the basis of sperm morphology, may choose a cell with poor chromatin, which may lead to poor embryo outcomes.

STUDY FUNDING/COMPETING INTEREST(S)

The project was funded by the National Health and Medical Research council, APP1118943. The authors have no conflict of interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

Oxytocin and social anxiety: Interactions with sex hormones

Oxytocin has been associated with anxiolytic and stress reducing effects in a number of studies. Less is known about the associations of endogenous oxytocin concentrations and their interaction with other hormones such as sex hormones in relation to self-reported anxiety levels. In this study, endogenous oxytocin and sex hormone levels were analyzed in 99 high (51 women) and 100 low (50 women) socially anxious individuals. Regression analyses showed that women with high oxytocin and estradiol levels reported a lower total Liebowitz Social Anxiety Score (LSAS) as well as a lower score on the subscale LSAS Fear. This association of hormonal interaction with social anxiety scores was significant in the subsample of high socially anxious women. In men there were no significant associations for endogenous hormones with LSAS scores. These findings suggest that in women the link between oxytocin and anxiety might be dependent on basal anxiety levels as well as on individual sex hormone levels.

Fast versus slow onset of depressive episodes: A clinical criterion for subtyping patients with major depression

Purpose:

The speed of onset of depressive episodes is a clinical aspect of affective disorders that has not been sufficiently investigated. Thus, we aimed to explore whether patients with fast onset of the full-blown depressive symptomatology (≤ 7 days) differ from those with slow onset (> 7 days) with regard to demographic and clinical aspects.

Subjects and methods:

Data were obtained within an observational study conducted in outpatients with major depression who were treated with duloxetine (30–120 mg/day). Onset of depression (without any preceding critical life event) was fast in 416 (less than one week) and slower in 2220 patients.

Results:

Compared to patients with slow onset, those with fast onset of depression had more suicide attempts in the previous 12 months (2.7% versus 1.3%, P = 0.046) and less somatic comorbidity (61.7% versus 74.1%, P < 0.0001). In addition, they were slightly younger at onset of depression (mean ± SD 40.2 ± 14.6 versus 42.8 ± 14.2 years, P < 0.001) and used analgesics at baseline significantly less frequently (22.8% versus 33.4%, P < 0.0001).

Discussion and conclusion:

The speed of onset of depression has to be regarded as a relevant clinical characteristic in patients with unipolar depression.

A 24-week multicentre, randomized, open-label, parallel-group study comparing the efficacy and safety of ixekizumab vs. fumaric acid esters and methotrexate in patients with moderate-to-severe plaque psoriasis naive to systemic treatment

Background

Interleukin‐17 antagonists have received a first‐line label for moderate‐to‐severe plaque psoriasis.

Objectives

We conducted the first head‐to‐head trial between the two most commonly used first‐line therapies in Germany, fumaric acid esters (FAEs) and methotrexate, and the interleukin‐17A antagonist, ixekizumab.

Methods

Systemic‐naive patients were randomized in this parallel‐group, active‐comparator, open‐label, rater‐blinded trial (each group n = 54). The primary outcome was the proportion of patients achieving ≥ 75% improvement in Psoriasis Area and Severity Index (PASI 75) at 24 weeks. Key secondary outcomes included 24‐week PASI 90 and 100, static Physician's Global Assessment (sPGA) score of 0 or 1, and Dermatology Life Quality Index (DLQI) score of 0 or 1. Safety events at week 24 were analysed using Fisher's exact test. Missing data were imputed using nonresponder imputation. The trial was registered at ClinicalTrials.gov (NCT02634801) and EudraCT (2015‐002649‐69).

Results

At week 24, more ixekizumab‐treated patients achieved PASI 75 [91% vs. 22% FAEs (P < 0·001) and 70% methotrexate (P = 0·014)], PASI 90 [80% vs. 9% FAEs (P < 0·001) and 39% methotrexate (P < 0·001)] and PASI 100 [41% vs. 4% FAEs (P < 0·001) and 13% methotrexate (P = 0·0041)], as well as sPGA (0,1) and DLQI (0,1).

Conclusions

Ixekizumab was superior in inducing PASI 75/90/100, sPGA (0,1) and DLQI (0,1) responses at week 24 compared with methotrexate and FAEs. Safety profiles for all treatments were consistent with prior studies.

What's already known about this topic?

Fumaric acid esters (FAEs) and methotrexate are two frequently used conventional systemic therapies for chronic plaque psoriasis.

A recent meta‐analysis of methotrexate showed a ≥ 75% reduction in Psoriasis Area and Severity Index (PASI 75) rate of 45·2% from primary end points at either 12 or 16 weeks.

Until recently, FAEs were licensed for psoriasis only in Germany, but were used in many other European countries as off‐label treatment of psoriasis. In 2017, the European Medicines Agency approved dimethyl fumarate, presumed to be the main active ingredient of FAEs, for the treatment of adult patients with moderate‐to‐severe chronic plaque psoriasis.

What does this study add?

This study is the first randomized, head‐to‐head trial comparing a biologic treatment with these therapies in a systemic‐treatment‐naive patient population.

This study shows the low tolerability of FAEs leading to a significant discontinuation rate, the better tolerability and moderate efficacy of methotrexate, and the good tolerability, fast onset of action and high efficacy of ixekizumab in an unbiased comparison.

Our findings reinforce the favourable risk–benefit profile of ixekizumab shown previously and provide further evidence of its efficacy at 24 weeks.

https://doi.org/10.1111/bjd.18905 available online

IL-3-producing basophils are required to exacerbate airway hyperresponsiveness in a murine inflammatory model

BACKGROUND

Basophils are commonly associated with allergic responses because of their ability to produce large amounts of pro-Th2 cytokines and histamine. However, the mechanisms through which bone marrow-resident basophils (BMRB) become fully competent cytokine and histamine producers in response to IgE crosslinking are poorly understood. Here, we sought to determine the role of IL-3 in promoting pro-Th2 basophils.

METHODS

BMRB and basophils exposed to IL-3 in vitro and in vivo were evaluated for their production of Th2 cytokines and histamine in response to FcεRI crosslinking on both protein and gene expression levels. In vivo relevance of our findings was assessed in a model of ovalbumin-induced allergic asthma using IL-3-deficient and wild-type mice in a protocol of adoptive basophil transfer.

RESULTS

We show that BMRB and basophils previously exposed to IL-3 differ in their ability to generate cytokines (IL-4, IL-6, IL-13, and GM-CSF) and histamine in response to FcεRI crosslinking, reflecting two stages of maturation. Exposure to IL-3 initiated an autocrine loop of endogenous IL-3 production that enhanced histamine and cytokine production upon FcεRI crosslinking. This increased responsiveness required calcium flux and was dependent on calcineurin and store-operated calcium channels. Our findings are of pathophysiological relevance, as assessed by the failure of IL-3-deficient mice to develop airway hyperreactivity, which could be restored by adoptive transfer of IL-3-derived basophils recovered from wild-type mice.

CONCLUSION

IL-3-dependent basophils promote Th2 allergic AHR, which designates the IL-3/basophil axis as a promising therapeutic target for the treatment of basophil-dependent asthma.

Performance of a composite flow moulded carbon fibre reinforced osteosynthesis plate

Non-metallic implants have the advantage over metallic implants of reduction in artefact with CT and MR diagnostic imaging. In-vivo performance of a carbon fibre reinforced polyetheretherketone radiolucent plate (Snake Plate [SP]) with high stiffness, and fixed angle converging screws was compared with a seven-hole titanium Locking Compression Plate (LCP), using a sheep tibial osteotomy model (gap 0.6 mm). The sheep were divided into two groups, and the osteotomies were stabilized with a SP (n=6) or a LCP (n=6). The callus dimensions were measured radiographically at zero, two, four, six and eight weeks. The animals were euthanatized after eight weeks. Osteotomised and contralateral tibiae were tested in pairs torsion, to determine strength and stiffness. In the radii of six separate sheep, initial vascular disturbance after plate implantation was evaluated. All of the sheep of the SP and LCP groups showed maximal callus areas at six weeks. The differences between the groups, in callus dimension, were not significant at any time point. The median values for relative reduction (100 x [operated – contralateral] / contralateral) in strength of osteotomized tibiae was ™13.93% for the SP group and ™7.49% for the LCP group (p = 0.5228), and for stiffness it was ™24.44 % for the SP group and ™27.08% for the LCP group (p = 0.6481). Neither the SP nor LCP caused any notable disturbance in periosteal circulation. The SP appears to represent a valuable alternative to metallic implants for shaft fracture repair. The main advantages of the SP are radiolucency, high deformation resistance, internal fixator concept and converging screw configuration for optimal loading conditions in the bone-implant construct.

Quantification of histomorphometric and structural bone changes in a sheep model for fracture treatment in osteoporotic bone

The histomorphometrical cancellous bone parameters of osteoporotic ewes were examined to establish a large animal model for the investigation of fracture treatment and healing in osteoporotic bone. Eighteen animals were divided into 2 groups. Group 1 (n = 8, age 3 to 5 years) served as an untreated control. In Group 2 (n = 10, age 7 to 9 years) osteoporosis was induced by means of ovariectomy, methylprednisolone application (average dose 160 mg/week) and Ca./Vit.D restricted diet during 7 months. Biopsies from iliac crest, femoral head and lumbar spine were harvested. Structural parameters from the biopsies were determined using μCT. In order to investigate static and dynamic parameters of bone remodelling, undecalcified sections were digitized and evaluated by means of image analysing software. Morphologically, bone area and trabecular thickness were reduced in osteoporotic sheep. Bone perimeter (−20%), trabecular number (−16%) and separation (+39%) showed a significant change in the iliac crest. The structure model index indicated a shift from the plate-to the rodmodel. At different skeletal sites of osteoporotic sheep bone resorption was significantly increased (250-675%), and bone formation significantly decreased (77-89%). Osteoid thickness (O.Th) was reduced (28-62%). In osteoporotic sheep the mean length of single labels was significantly shortened (64-73%) and the mineralising surface showed a significant decrease (80-92%). The mineralisation of the osteoid was comparable to the control group. The histomorphometrical changes in this sheep model of osteoporosis are comparable to the human situation of a combined post-menopausal and steroid-induced osteoporosis.

Measurement of bone surface strains on the sheep metacarpus in vivo and ex vivo

Bone surface strains were measured on the dorsal ovine metacarpus during normal locomotion on a treadmill at different walking speeds to determine physiological strain levels. These measured strains were related to the strains measured in an ex vivo model of the sheep forelimb with two types of load application: loading by two Schanz-screws and loading via the radius. In vivo, the average surface strains were found to be dependent upon body weight as well as the walking speed. The orientation of the peak principal strain corresponded to the longitudinal axis of the bone. Ex vivo, loads applied via Schanz screws in the screw-loading model lead to strains on the dorsal metacarpus that corresponds to strains experienced in vivo during intermittent peak loads. Screw loading imparted primarily a bending load to the metacarpus, with the dorsal aspect in compression and the palmar aspect in tension. Loads, applied via the radius and the hoof in the radius-loading model, resulted in bone surface strains comparable to those measured during slow walking in vivo. In both ex vivo loading situations, peak strain orientation was parallel to the longitudinal axis of the sheep metacarpus. In conclusion, the results show that although the ex vivo loading models do not exactly replicate the load experienced in vivo, the magnitude and orientation of the principal strains on the dorsal metacarpus are within the range of strains occurring during normal physiological loading. These data validate the physiological significance of the ex vivo model and aid in understanding effects of mechanical loading on interstitial fluid flow and mass transport through bone.

The effect of gestagens on bone turnover in sheep

The effects of two gestagens on bone turnover were investigated in three groups of female sheep comparable in age and weight. Group A (n = 10) was given a single intramuscular injection of 50 mg chlormadinon acetate (CMA), group B (n = 9) received 140 mg medroxyprogesterone acetate (MPA), and control group C (n = 9) received 5 ml physiological NaCI-solution. Plasma progesterone was measured weekly over 3 months. Bone mineral density (BMD) in the right distal tibia and calcaneus were determined every four weeks during the four months of the study duration, using peripheral quantitative computed tomography (pQCT). At the same times total alkaline phosphatase (AP) was determined. No significant changes of BMD were found in the three groups during the four months. Total alkaline phosphatase showed a significant decrease of 36-45% in all groups during the first six weeks. Sheep seem to have a comparable bone metabolism to humans with respect to the short term effect of gestagens, i. e. MPA and CMA.

Vestibulo-ocular reflex dynamics with head-impulses discriminates spinocerebellar ataxias types 1, 2 and 3 and Friedreich ataxia

OBJECTIVE

Although the diagnosis of inherited ataxias is ultimately genetic, this usually means an extensive and expensive process. This justifies the search for distinct clinical signs that may potentially help orient molecular diagnosis.

METHODS

We explored the vestibulo-ocular reflex (VOR) with the video Head Impulse Test in patients diagnosed with spinocerebellar ataxia (SCA) type 3 (n = 15), type 1 (n = 4) and type 2 (n = 4), Friedreich's ataxia (FA) (n = 9) and healthy controls (n = 40). We estimated the latency, regression (VORr) and instantaneous VOR gain at 40, 60 and 80 ms (VOR40, VOR60 and VOR80), and determined the latency, peak-velocity and occurrence rate of catch-up saccades triggered with head-impulses.

RESULTS

VOR latency was higher in FA (p < 0.001) and SCA3 (p = 0.02) as compared to controls, discriminating FA from other ataxic patients with an overall diagnostic accuracy of 88%. VORr, VOR40 and VOR60 were significantly lower in FA and SCA3 (p < 0.01). VOR80 was only significantly lower than controls in SCA3 (p < 0.01), discriminating these from other ataxic patients with an overall diagnostic accuracy of 78%. Covert saccades were only triggered in SCA3 but with low occurrence rate and peak velocity (11.1 ± 28.5% and 77.50 ± 15.30°/s) whereas overt saccades were present in all groups. VORr gain showed a negative correlation with disease severity evaluated with SARA (Spearman r = -0.46, p = 0.01).

CONCLUSIONS

vHIT provides phenotypic information that differentiates these autosomal ataxias and can serve as a strategy to orient genetic diagnosis. A correlation between VOR and SARA raises the possibility of using VOR gain as a neurophysiologic biomarker for disease severity.

Dosimetrische Grundlagen für die endo vaskuläre Therapie mit Re-188 zur Prävention der Restenose nach Angioplastie

Ziel: Für die endovaskuläre Brachytherapie stehen unterschiedliche Radionuklide zur Verfügung. Ein interessantes Konzept ist die Nutzung eines flüssigen Betastrahlers in einem Ballonkatheter. Re-188 kann aus einem Generatorsystem gewonnen werden und steht somit täglich zur Verfügung. Es sollten dosimetrische Daten erhoben werden. Methode: Es wurde die radiale Abnahme der Dosis von Re-188 bei einem typischen Dilatationskatheter (Durchmesser 3 mm, Länge 20 mm) berechnet und mit TLD-Messungen verglichen. Ergebnisse: Bei einer spezifischen Aktivität von 370 MBq/ml konnten 0,3 Gy pro 1 min in 0,5 mm Abstand von der Ballonwand gemessen werden. Doppelmessungen wiesen eine Abweichung von 3% auf. Ein schneller Dosisabfall von 50% innerhalb von 0,5 mm bzw. von 90% innerhalb von 2,5 mm wurde beobachtet. Meßwerte und Berechnungen stimmten gut überein. Die Daten von Re-188 und Y-90 entsprechen sich weitgehend. Schlußfolgerung: Berechnungen über die Dosisverteilung von Re-188 stimmen mit TLD-Messungen gut überein. Bei einer spezifischen Aktivität von 1,85 GBq/ml können in 2-3 Minuten 10-15 Gy an der Gefäßwand einer Koronararterie appliziert werden. Gegenüber radioaktiven Stents oder radioaktiven Drähten bietet sich hiermit eine einfache Alternative für die Prävention der Restenose an.

Optimization of corticosteroid induced osteoporosis in ovariectomized sheep

During osteoporosis induction in sheep, side effects of the steroids were observed in previous studies. The aim of this study was to improve the induction regimen consisting of ovariectomy, calcium/vitamin D- restricted diet and methylprednisolone (-MP)- medication with respect to the bone metabolism and to reduce the adverse side effects. Thirty-six ewes (age 6.5 ± 0.6 years) were divided into four MP-administration groups (n=9) with a total dose of 1800 mg MP: group 1: 20 mg/day, group 2: 60 mg/ every third day, group 3: 3x 500 mg and 1x 300 mg at intervals of three weeks, group 4: weekly administration, starting at 70 mg and weekly reduction by 10 mg. After double-labelling with Calcein Green and Xylenol Orange, bone biopsy specimens were taken from the iliac crest (IC) at the beginning and four weeks after the last MP injection, and additionally from the vertebral body (VB) at the end of the experiment. Bone samples were processed into stained and fluorescent sections, static and dynamic measurements were performed. There were no significant differences for static parameters between the groups initially. The bone perimeter and the bone area values were significantly higher in the VB than in the IC (Pm: 26%, p<0.0001, Ar: 11%, p<0.0166). A significant decrease (20%) of the bone area was observed after corticosteroid- induced osteoporosis (p<0.0004). For the dynamic parameters, no significant difference between the groups was found. Presence of Calcein Green and Xylenol Orange labels were noted in 50% of the biopsies in the IC, 100% in the VB. Group 3 showed the lowest prevalence of adverse side effects. The bone metabolism changes were observed in all four groups, and the VB bone metabolism was higher when compared to the IC. In conclusion, when using equal amounts of steroids adverse side effects can be reduced by decreasing the number of administrations without reducing the effect regarding corticosteroid- induced osteoporosis. This information is useful to reduce the discomfort of the animals in this sheep model of corticosteroid-induced osteoporosis.

Anticompensatory quick eye movements after head impulses: A peripheral vestibular sign in spontaneous nystagmus

BACKGROUND

Differentiating central from peripheral origins of spontaneous nystagmus (SN) is challenging. Looking for a simple sign of peripheral disease with the video Head Impulsive Test we noticed anti-compensatory eye movements (AQEM) in patients with peripheral etiologies of spontaneous nystagmus (SN). Here we assess the diagnostic accuracy of AQEM in differentiating peripheral from central vestibular disorders.

METHODS

We recorded the eye movements in response to horizontal head impulses in a group of 43 consecutive patients with acute vestibular syndrome (12 with central, 31 with peripheral disorders), 5 patients after acute vestibular neurectomy (positive controls) and 39 healthy subjects (negative controls). AQEM were defined as quick eye movements (peak velocity above 50°/s) in the direction of the head movement.

RESULTS

All patients with peripheral disorders and positive controls had AQEM (latency 231 ± 53 ms, amplitude 3.4 ± 1.4°, velocity 166 ± 55°/s) when their head was moved to the opposite side of the lesion. Central patients did not have AQEM. AQEM occurrence rate was higher in peripheral patients with contralesional (74 ± 4%, mean ± SD) in comparison to ipsilesional (1 ± 4%) impulses (p< 0.001). Overall diagnostic accuracy for differentiating central from peripheral patients was 96% (95% CI for AUC ROC curve: 0.90 to 1.0) for VOR gain and 100% (95% CI: 1.0 to 1.0) for AQEM occurrence rate.

CONCLUSIONS

These results suggest that AQEM are a sign of vestibular imbalance in a peripheral deficit. In addition to VOR gain they should be added to the evaluation of the head impulse test.

Real-time computer-based visual feedback improves visual acuity in downbeat nystagmus - a pilot study

BACKGROUND

Patients with downbeat nystagmus syndrome suffer from oscillopsia, which leads to an unstable visual perception and therefore impaired visual acuity. The aim of this study was to use real-time computer-based visual feedback to compensate for the destabilizing slow phase eye movements.

METHODS

The patients were sitting in front of a computer screen with the head fixed on a chin rest. The eye movements were recorded by an eye tracking system (EyeSeeCam®). We tested the visual acuity with a fixed Landolt C (static) and during real-time feedback driven condition (dynamic) in gaze straight ahead and (20°) sideward gaze. In the dynamic condition, the Landolt C moved according to the slow phase eye velocity of the downbeat nystagmus. The Shapiro-Wilk test was used to test for normal distribution and one-way ANOVA for comparison.

RESULTS

Ten patients with downbeat nystagmus were included in the study. Median age was 76 years and the median duration of symptoms was 6.3 years (SD +/- 3.1y). The mean slow phase velocity was moderate during gaze straight ahead (1.44°/s, SD +/- 1.18°/s) and increased significantly in sideward gaze (mean left 3.36°/s; right 3.58°/s). In gaze straight ahead, we found no difference between the static and feedback driven condition. In sideward gaze, visual acuity improved in five out of ten subjects during the feedback-driven condition (p = 0.043).

CONCLUSIONS

This study provides proof of concept that non-invasive real-time computer-based visual feedback compensates for the SPV in DBN. Therefore, real-time visual feedback may be a promising aid for patients suffering from oscillopsia and impaired text reading on screen. Recent technological advances in the area of virtual reality displays might soon render this approach feasible in fully mobile settings.