The influence of obstructive sleep apnea and continuous positive airway pressure on the nasal microbiome.

OBJECTIVE: The aim of this study was to investigate the influence of obstructive sleep apnea and continuous positive airway pressure on the nasal microbiome. PATIENTS AND METHODS: Endonasal swabs from the olfactory groove of 22 patients with moderate and severe obstructive sleep apnea (OSA) and a control group of 17 healthy controls were obtained at the Department of Otorhinolaryngology of the Friedrich-Alexander-Universität Erlangen-Nürnberg. 16S rRNA gene sequencing was performed to further evaluate the endonasal microbiome. In a second step, the longitudinal influence of continuous positive airway pressure (CPAP) therapy on the nasal microbiome was investigated (3-6 and 6-9 months). RESULTS: Analysis of the bacterial load and ß-diversity showed no significant differences between the groups, although patients with severe OSA showed increased α-diversity compared to the control group, while those with moderate OSA showed decreased α-diversity. The evaluation of longitudinal changes in the nasal microbiota during CPAP treatment showed no significant difference in α- or ß-diversity. However, the number of bacteria for which a significant difference between moderate and severe OSA was found in the linear discriminant analysis decreased during CPAP treatment. CONCLUSIONS: Long-term CPAP treatment showed an alignment of the composition of the nasal microbiome in patients with moderate and severe OSA as well as an alignment of biodiversity with that of the healthy control group. This change in the composition of the microbiome could be both part of the therapeutic effect in CPAP therapy and a promoting factor of the adverse side effects of the therapy. Further studies are needed to investigate whether the endonasal microbiome is related to CPAP compliance and whether CPAP compliance can be positively influenced in the future by therapeutic modification of the microbiome.

Gait variability as digital biomarker of disease severity in Huntington's disease.

BACKGROUND: Impaired gait plays an important role for quality of life in patients with Huntington's disease (HD). Measuring objective gait parameters in HD might provide an unbiased assessment of motor deficits in order to determine potential beneficial effects of future treatments. OBJECTIVE: To objectively identify characteristic features of gait in HD patients using sensor-based gait analysis. Particularly, gait parameters were correlated to the Unified Huntington's Disease Rating Scale, total motor score (TMS), and total functional capacity (TFC). METHODS: Patients with manifest HD at two German sites (n = 43) were included and clinically assessed during their annual ENROLL-HD visit. In addition, patients with HD and a cohort of age- and gender-matched controls performed a defined gait test (4 × 10 m walk). Gait patterns were recorded by inertial sensors attached to both shoes. Machine learning algorithms were applied to calculate spatio-temporal gait parameters and gait variability expressed as coefficient of variance (CV). RESULTS: Stride length (- 15%) and gait velocity (- 19%) were reduced, while stride (+ 7%) and stance time (+ 2%) were increased in patients with HD. However, parameters reflecting gait variability were substantially altered in HD patients (+ 17% stride length CV up to + 41% stride time CV with largest effect size) and showed strong correlations to TMS and TFC (0.416 ≤ rSp ≤ 0.690). Objective gait variability parameters correlated with disease stage based upon TFC. CONCLUSIONS: Sensor-based gait variability parameters were identified as clinically most relevant digital biomarker for gait impairment in HD. Altered gait variability represents characteristic irregularity of gait in HD and reflects disease severity.

[Cellular replacement strategies and adult neurogenesis in idiopathic Parkinson's disease]. / Zellersatz und adulte Neurogenese beim idiopathischen Parkinson-Syndrom.

Parkinson's disease (PD) is the most common age-related movement disorder and characterized by slowly progressive neurodegeneration resulting in motor symptoms, such as bradykinesia, rigidity, tremor and postural instability. Moreover, non-motor symptoms, such as hyposmia, anxiety and depression reduce the quality of life in PD. Motor symptoms are associated with a distinct striatal dopaminergic deficit resulting from axonal dysfunction and neuronal loss in the substantia nigra (SN). Recent progress in stem cell technology allows the optimization of cellular transplantation strategies in order to alleviate the motor deficit, which potentially leads to a reactivation of this therapeutic strategy. Besides neurodegenerative processes impaired adult neurogenesis and consequentially reduced endogenous cellular plasticity may play an important role in PD. This article discusses the notion that non-motor symptoms in PD may partly be explained by reduced adult neurogenesis in the olfactory bulb and hippocampus.

[Vascular parkinsonism]. / Vaskuläres Parkinson-Syndrom (= Parkinsonismus bei vaskulärer Enzephalopathie).

Parkinsonism may result from cerebral vascular disorders that feature white matter lesions and small vessel pathology. Vascular Parkinsonism typically presents as lower body Parkinsonism with predominant gait impairment. Urinary incontinence and cognitive decline are additional features of the disease. There is a considerable overlap between vascular Parkinsonism and vascular dementia. We review the clinical characteristics of vascular Parkinsonism and discuss the current treatment approaches, as well as the role of brain imaging for the diagnostic workup. .

From sweet to sweat: Hedonic olfactory range is impaired in Parkinson's disease.

INTRODUCTION: Olfactory dysfunction and neuropsychological symptoms like depression and anhedonia are common non-motor symptoms in Parkinson's disease (PD). The assessment of both functional domains includes clinical examination, olfactory testing, and standardized questionnaires. While olfaction is readily assessed by functional tests, the distinction of anhedonia as a separate symptom from other depressive symptoms is challenging. Thus, a test focusing on the assessment of hedonic olfaction may be helpful in the assessment of neuropsychological symptoms in PD. METHODS: We examined anhedonia by evaluating the perception of pleasantness of odors in PD patients (n = 57) and healthy controls (n = 46). Pleasantness of odors was registered on a visual 9-point scale. For the assessment of anhedonia we used the Snaith-Hamilton-Pleasure-Scale (SHAPS). Depression was evaluated with the Zung Self-Rating Depression Scale and the Beck Depression Inventory II. RESULTS: PD patients showed a substantial reduction in hedonic olfaction compared to controls (hedonic score: 1.5 vs. 2.2). Hyposmia, one of the most prevalent non-motor symptoms in PD, was a confounding factor. However, even normosmic PD patients showed a reduced hedonic olfaction compared to controls (hedonic score: 1.6 vs. 2.2). Furthermore, we observed a correlation between hedonic olfaction and the SHAPS-score for PD patients even though positive SHAPS-rating was observed in 9% of PD patients only, while no correlation to depression was present. CONCLUSION: These findings suggest that reduced hedonic olfaction might be an additional neuropsychological feature, probably giving insights into changes in hedonic tone complementary to hyposmia and depression in PD.

Impaired olfactory bulb neurogenesis depends on the presence of human wild-type alpha-synuclein.

Synucleinopathies including Parkinson's disease (PD) are characterized by the accumulation of alpha-synuclein (α-syn) within neural cell bodies and their processes. Transgenic mice overexpressing human wild-type or mutant forms of α-syn under the control of different promoters were developed to analyse the underlying neuropathology of PD. One of the earliest clinical symptoms associated with PD is olfactory impairment. The generation of new neurons persists up to adulthood in mammals, in particular the olfactory bulb (OB). In order to assess this process in relation to α-syn accumulation, we used mice overexpressing human wild-type α-syn under the regulatable control (tet-off) of the calcium/calmodulin-dependent protein kinase IIα-promoter (CaMKII). We observed a decrease in OB neurogenesis in transgenic animals compared to controls using 5-bromo-2'-deoxyuridine (BrdU) to label newly generated cells (neuron-specific nuclear protein; NeuN). After cessation of transgene expression we detected an increase in newly generated cells both in granular (GCL) and glomerular (GLOM) layers of the OB. This led to a rescue of newly generated neurons (BrdU(+)/NeuN(+)) within the GLOM with a distinct specificity for the dopaminergic subpopulation. In contrast, we did not detect a cell-specific rescue of neuronal cells in the GCL suggesting diverse effects of alpha-synucleinopathy in both interneuronal layers of the OB. Colabelling of BrdU with glial markers showed that a differentiation into neither astroglia nor microglia attributed to the observed phenotype in the GCL. In particular, BrdU(+) particles located within microglial cells were predominantly associated close to the membrane therefore the resembling phagocytosed nuclear fragments of BrdU(+) cells. Thus, our study further contributes insights into α-syn accumulation as a causative player in the impairment of adult neurogenesis and emphasizes its diverse role in cell renewal of distinct OB cell layers.