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  • MDPI AG  (16)
  • Witte, Otto W.  (16)
  • 1
    In: Cells, MDPI AG, Vol. 11, No. 4 ( 2022-02-11), p. 625-
    Abstract: Extracellular vesicles (EVs), including small EVs (sEVs), are involved in neuroinflammation and neurodegenerative diseases, including Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Yet, increased neuroinflammation can also be detected in the aging brain, and it is associated with increased glial activation. Changes in EV concentration are reported in aging tissues and senescence cells, suggesting a role of EVs in the process of aging. Here, we investigated the effect of peripheral sEVs from aged animals on neuroinflammation, specifically on glial activation. sEVs were isolated from the peripheral blood of young (3 months) and aged (24 months) C57BL/6J wildtype mice and injected into the peripheral blood from young animals via vein tail injections. The localization of EVs and the expression of selected genes involved in glial cell activation, including Gfap, Tgf-β, Cd68, and Iba1, were assessed in brain tissue 30 min, 4 h, and 24 h after injection. We found that sEVs from peripheral blood of aged mice but not from young mice altered gene expression in the brains of young animals. In particular, the expression of the specific astrocyte marker, Gfap, was significantly increased, indicating a strong response of this glial cell type. Our study shows that sEVs from aged mice can pass the blood-brain barrier (BBB) and induce glial cell activation.
    Type of Medium: Online Resource
    ISSN: 2073-4409
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661518-6
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  • 2
    Online Resource
    Online Resource
    MDPI AG ; 2019
    In:  Cells Vol. 8, No. 12 ( 2019-11-29), p. 1546-
    In: Cells, MDPI AG, Vol. 8, No. 12 ( 2019-11-29), p. 1546-
    Abstract: Replicative senescence has initially been defined as a stress reaction of replication-competent cultured cells in vitro, resulting in an ultimate cell cycle arrest at preserved growth and viability. Classically, it has been linked to critical telomere curtailment following repetitive cell divisions, and later described as a response to oncogenes and other stressors. Currently, there are compelling new directions indicating that a comparable state of cellular senescence might be adopted also by postmitotic cell entities, including terminally differentiated neurons. However, the cellular upstream inducers and molecular downstream cues mediating a senescence-like state in neurons (amitosenescence) are ill-defined. Here, we address the phenomenon of abortive atypical cell cycle activity in light of amitosenescence, and discuss why such replicative reprogramming might provide a yet unconsidered source to explain senescence in maturated neurons. We also hypothesize the existence of a G0 subphase as a priming factor for cell cycle re-entry, in analogy to discoveries in quiescent muscle stem cells. In conclusion, we propose a revision of our current view on the process and definition of senescence by encompassing a primarily replication-incompetent state (amitosenescence), which might be expanded by events of atypical cell cycle activity (pseudomitosenescence).
    Type of Medium: Online Resource
    ISSN: 2073-4409
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2661518-6
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  • 3
    Online Resource
    Online Resource
    MDPI AG ; 2020
    In:  International Journal of Molecular Sciences Vol. 21, No. 7 ( 2020-04-02), p. 2477-
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 21, No. 7 ( 2020-04-02), p. 2477-
    Abstract: Still unresolved is the question of how a lifetime accumulation of somatic gene copy number alterations impact organ functionality and aging and age-related pathologies. Such an issue appears particularly relevant in the broadly post-mitotic central nervous system (CNS), where non-replicative neurons are restricted in DNA-repair choices and are prone to accumulate DNA damage, as they remain unreplaced over a lifetime. Both DNA injuries and consecutive DNA-repair strategies are processes that can evoke extrachromosomal circular DNA species, apparently from either part of the genome. Due to their capacity to amplify gene copies and related transcripts, the individual cellular load of extrachromosomal circular DNAs will contribute to a dynamic pool of additional coding and regulatory chromatin elements. Analogous to tumor tissues, where the mosaicism of circular DNAs plays a well-characterized role in oncogene plasticity and drug resistance, we suggest involvement of the “circulome” also in the CNS. Accordingly, we summarize current knowledge on the molecular biogenesis, homeostasis and gene regulatory impacts of circular extrachromosomal DNA and propose, in light of recent discoveries, a critical role in CNS aging and neurodegeneration. Future studies will elucidate the influence of individual extrachromosomal DNA species according to their sequence complexity and regional distribution or cell-type-specific abundance.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 4
    In: Journal of Clinical Medicine, MDPI AG, Vol. 10, No. 20 ( 2021-10-15), p. 4734-
    Abstract: Background: Infective endocarditis (IE) requires multidisciplinary management. We established an endocarditis team within our hospital in 2011 and a state-wide endocarditis network with referring hospitals in 2015. We aimed to investigate their impact on perioperative outcomes. Methods: We retrospectively analyzed data from patients operated on for IE in our center between 01/2007 and 03/2018. To investigate the impact of the endocarditis network on referral latency and pre-operative complications we divided patients into two eras: before (n = 409) and after (n = 221) 01/2015. To investigate the impact of the endocarditis team on post-operative outcomes we conducted multivariate binary logistic regression analyses for the whole population. Kaplan–Meier estimates of 5-year survival were reported. Results: In the second era, after establishing the endocarditis network, the median time from symptoms to referral was halved (7 days (interquartile range: 2–19) vs. 15 days (interquartile range: 6–35)), and pre-operative endocarditis-related complications were reduced, i.e., stroke (14% vs. 27%, p 〈 0.001), heart failure (45% vs. 69%, p 〈 0.001), cardiac abscesses (24% vs. 34%, p = 0.018), and acute requirement of hemodialysis (8% vs. 14%, p = 0.026). In both eras, a lack of recommendations from the endocarditis team was an independent predictor for in-hospital mortality (adjusted odds ratio: 2.12, 95% CI: 1.27–3.53, p = 0.004) and post-operative stroke (adjusted odds ratio: 2.23, 95% CI: 1.12–4.39, p = 0.02), and was associated with worse 5-year survival (59% vs. 40%, log-rank 〈 0.001). Conclusion: The establishment of an endocarditis network led to the earlier referral of patients with fewer pre-operative endocarditis-related complications. Adhering to endocarditis team recommendations was an independent predictor for lower post-operative stroke and in-hospital mortality, and was associated with better 5-year survival.
    Type of Medium: Online Resource
    ISSN: 2077-0383
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2662592-1
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  • 5
    In: International Journal of Molecular Sciences, MDPI AG, Vol. 23, No. 6 ( 2022-03-10), p. 3000-
    Abstract: Efficient purification of viable neural cells from the mature CNS has been historically challenging due to the heterogeneity of the inherent cell populations. Moreover, changes in cellular interconnections, membrane lipid and cholesterol compositions, compartment-specific biophysical properties, and intercellular space constituents demand technical adjustments for cell isolation at different stages of maturation and aging. Though such obstacles are addressed and partially overcome for embryonic premature and mature CNS tissues, procedural adaptations to an aged, progeroid, and degenerative CNS environment are underrepresented. Here, we describe a practical workflow for the acquisition and phenomapping of CNS neural cells at states of health, physiological and precocious aging, and genetically provoked neurodegeneration. Following recent, unprecedented evidence of post-mitotic cellular senescence (PoMiCS), the protocol appears suitable for such de novo characterization and phenotypic opposition to classical senescence. Technically, the protocol is rapid, efficient as for cellular yield and well preserves physiological cell proportions. It is suitable for a variety of downstream applications aiming at cell type-specific interrogations, including cell culture systems, Flow-FISH, flow cytometry/FACS, senescence studies, and retrieval of omic-scale DNA, RNA, and protein profiles. We expect suitability for transfer to other CNS targets and to a broad spectrum of engineered systems addressing aging, neurodegeneration, progeria, and senescence.
    Type of Medium: Online Resource
    ISSN: 1422-0067
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2019364-6
    SSG: 12
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  • 6
    In: Brain Sciences, MDPI AG, Vol. 11, No. 8 ( 2021-07-21), p. 960-
    Abstract: Studies investigating human brain response to emotional stimuli—particularly high-arousing versus neutral stimuli—have obtained inconsistent results. The present study was the first to combine magnetoencephalography (MEG) with the bootstrapping method to examine the whole brain and identify the cortical regions involved in this differential response. Seventeen healthy participants (11 females, aged 19 to 33 years; mean age, 26.9 years) were presented with high-arousing emotional (pleasant and unpleasant) and neutral pictures, and their brain responses were measured using MEG. When random resampling bootstrapping was performed for each participant, the greatest differences between high-arousing emotional and neutral stimuli during M300 (270–320 ms) were found to occur in the right temporo-parietal region. This finding was observed in response to both pleasant and unpleasant stimuli. The results, which may be more robust than previous studies because of bootstrapping and examination of the whole brain, reinforce the essential role of the right hemisphere in emotion processing.
    Type of Medium: Online Resource
    ISSN: 2076-3425
    Language: English
    Publisher: MDPI AG
    Publication Date: 2021
    detail.hit.zdb_id: 2651993-8
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  • 7
    In: Cells, MDPI AG, Vol. 11, No. 23 ( 2022-11-30), p. 3864-
    Abstract: Cognitive decline is one of the greatest health threats of old age and the maintenance of optimal brain function across a lifespan remains a big challenge. The hippocampus is considered particularly vulnerable but there is cross-species consensus that its functional integrity benefits from the early and continuous exercise of demanding physical, social and mental activities, also referred to as environmental enrichment (EE). Here, we investigated the extent to which late-onset EE can improve the already-impaired cognitive abilities of lifelong deprived C57BL/6 mice and how it affects gene expression in the hippocampus. To this end, 5- and 24-month-old mice housed in standard cages (5mSC and 24mSC) and 24-month-old mice exposed to EE in the last 2 months of their life (24mEE) were subjected to a Barnes maze task followed by next-generation RNA sequencing of the hippocampal tissue. Our analyses showed that late-onset EE was able to restore deficits in spatial learning and short-term memory in 24-month-old mice. These positive cognitive effects were reflected by specific changes in the hippocampal transcriptome, where late-onset EE affected transcription much more than age (24mSC vs. 24mEE: 1311 DEGs, 24mSC vs. 5mSC: 860 DEGs). Remarkably, a small intersection of 72 age-related DEGs was counter-regulated by late-onset EE. Of these, Bcl3, Cttnbp2, Diexf, Esr2, Grb10, Il4ra, Inhba, Rras2, Rps6ka1 and Socs3 appear to be particularly relevant as key regulators involved in dendritic spine plasticity and in age-relevant molecular signaling cascades mediating senescence, insulin resistance, apoptosis and tissue regeneration. In summary, our observations suggest that the brains of aged mice in standard cage housing preserve a considerable degree of plasticity. Switching them to EE proved to be a promising and non-pharmacological intervention against cognitive decline.
    Type of Medium: Online Resource
    ISSN: 2073-4409
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2661518-6
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  • 8
    In: Cells, MDPI AG, Vol. 12, No. 3 ( 2023-01-28), p. 432-
    Abstract: Aging is accompanied by macro-structural alterations in the brain that may relate to age-associated cognitive decline. Animal studies could allow us to study this relationship, but so far it remains unclear whether their structural aging patterns correspond to those in humans. Therefore, by applying magnetic resonance imaging (MRI) and deformation-based morphometry (DBM), we longitudinally screened the brains of male RccHan:WIST rats for structural changes across their average lifespan. By combining dedicated region of interest (ROI) and voxel-wise approaches, we observed an increase in their global brain volume that was superimposed by divergent local morphologic alterations, with the largest aging effects in early and middle life. We detected a modality-dependent vulnerability to shrinkage across the visual, auditory, and somato-sensory cortical areas, whereas the piriform cortex showed partial resistance. Furthermore, shrinkage emerged in the amygdala, subiculum, and flocculus as well as in frontal, parietal, and motor cortical areas. Strikingly, we noticed the preservation of ectorhinal, entorhinal, retrosplenial, and cingulate cortical regions, which all represent higher-order brain areas and extraordinarily grew with increasing age. We think that the findings of this study will further advance aging research and may contribute to the establishment of interventional approaches to preserve cognitive health in advanced age.
    Type of Medium: Online Resource
    ISSN: 2073-4409
    Language: English
    Publisher: MDPI AG
    Publication Date: 2023
    detail.hit.zdb_id: 2661518-6
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  • 9
    In: Brain Sciences, MDPI AG, Vol. 10, No. 3 ( 2020-03-04), p. 147-
    Abstract: Abnormal emotional reactions of the brain in patients with facial nerve paralysis have not yet been reported. This study aims to investigate this issue by applying a machine-learning algorithm that discriminates brain emotional activities that belong either to patients with facial nerve paralysis or to healthy controls. Beyond this, we assess an emotion rating task to determine whether there are differences in their experience of emotions. MEG signals of 17 healthy controls and 16 patients with facial nerve paralysis were recorded in response to picture stimuli in three different emotional categories (pleasant, unpleasant, and neutral). The selected machine learning technique in this study was the logistic regression with LASSO regularization. We demonstrated significant classification performances in all three emotional categories. The best classification performance was achieved considering features based on event-related fields in response to the pleasant category, with an accuracy of 0.79 (95% CI (0.70, 0.82)). We also found that patients with facial nerve paralysis rated pleasant stimuli significantly more positively than healthy controls. Our results indicate that the inability to express facial expressions due to peripheral motor paralysis of the face might cause abnormal brain emotional processing and experience of particular emotions.
    Type of Medium: Online Resource
    ISSN: 2076-3425
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2651993-8
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  • 10
    In: Brain Sciences, MDPI AG, Vol. 10, No. 6 ( 2020-06-06), p. 352-
    Abstract: The processing of emotions in the human brain is an extremely complex process that extends across a large number of brain areas and various temporal processing steps. In the case of magnetoencephalography (MEG) data, various frequency bands also contribute differently. Therefore, in most studies, the analysis of emotional processing has to be limited to specific sub-aspects. Here, we demonstrated that these problems can be overcome by using a nonparametric statistical test called the cluster-based permutation test (CBPT). To the best of our knowledge, our study is the first to apply the CBPT to MEG data of brain responses to emotional stimuli. For this purpose, different emotionally impacting (pleasant and unpleasant) and neutral pictures were presented to 17 healthy subjects. The CBPT was applied to the power spectra of five brain frequencies, comparing responses to emotional versus neutral stimuli over entire MEG channels and time intervals within 1500 ms post-stimulus. Our results showed significant clusters in different frequency bands, and agreed well with many previous emotion studies. However, the use of the CBPT allowed us to easily include large numbers of MEG channels, wide frequency, and long time-ranges in one study, which is a more reliable alternative to other studies that consider only specific sub-aspects.
    Type of Medium: Online Resource
    ISSN: 2076-3425
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2651993-8
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