Dendritic Core-Multishell Nanocarriers in Murine Models of Healthy and Atopic Skin

Dendritic hPG-amid-C18-mPEG core-multishell nanocarriers (CMS) represent a novel class of unimolecular micelles that hold great potential as drug transporters, e.g., to facilitate topical therapy in skin diseases. Atopic dermatitis is among the most common inflammatory skin disorders with complex barrier alterations which may affect the efficacy of topical treatment. Here, we tested the penetration behavior and identified target structures of unloaded CMS after topical administration in healthy mice and in mice with oxazolone-induced atopic dermatitis. We further examined whole body distribution and possible systemic side effects after simulating high dosage dermal penetration by subcutaneous injection. Following topical administration, CMS accumulated in the stratum corneum without penetration into deeper viable epidermal layers. The same was observed in atopic dermatitis mice, indicating that barrier alterations in atopic dermatitis had no influence on the penetration of CMS. Following subcutaneous injection, CMS were deposited in the regional lymph nodes as well as in liver, spleen, lung, and kidney. However, in vitro toxicity tests, clinical data, and morphometry- assisted histopathological analyses yielded no evidence of any toxic or otherwise adverse local or systemic effects of CMS, nor did they affect the severity or course of atopic dermatitis. Taken together, CMS accumulate in the stratum corneum in both healthy and inflammatory skin and appear to be highly biocompatible in the mouse even under conditions of atopic dermatitis and thus could potentially serve to create a depot for anti-inflammatory drugs in the skin

Tracking CNS and systemic sources of oxidative stress during the course of chronic neuroinflammation

The functional dynamics and cellular sources of oxidative stress are central to understanding MS pathogenesis but remain elusive, due to the lack of appropriate detection methods. Here we employ NAD(P)H fluorescence lifetime imaging to detect functional NADPH oxidases (NOX enzymes) in vivo to identify inflammatory monocytes, activated microglia, and astrocytes expressing NOX1 as major cellular sources of oxidative stress in the central nervous system of mice affected by experimental autoimmune encephalomyelitis (EAE). This directly affects neuronal function in vivo, indicated by sustained elevated neuronal calcium. The systemic involvement of oxidative stress is mirrored by overactivation of NOX enzymes in peripheral CD11b(+) cells in later phases of both MS and EAE. This effect is antagonized by systemic intake of the NOX inhibitor and anti-oxidant epigallocatechin-3-gallate. Together, this persistent hyper-activation of oxidative enzymes suggests an "oxidative stress memory" both in the periphery and CNS compartments, in chronic neuroinflammation

Polymere Core-Multishell-Nanocarrier zum topischen Wirkstofftransport durch die Haut: Nanocarrier-Verteilung, Transport und Wirksamkeit bei der Behandlung entzündlicher Hautveränderungen

Polymeric Core-Multishell-Nanocarriers (CMS) are a family of molecules designed to function as universal drug carriers. Their architecture resembles unimolecular micelles/liposomes, with shell-like, hydrophobic, and hydrophilic domains. Studies using ex vivo/in vitro conditions have shown that they can be used to topically deliver drugs to the skin, including strongly hydrophobic drugs in water-based formulations. Interestingly, these studies reported that CMS not only successfully delivered cargo substances, but in fact increased their concentrations in the target area, the viable skin. Along with the relatively good biocompatibility reported, these properties make them interesting as tools for the treatment of inflammatory skin conditions and other topical applications. The work described here is part of a project that aimed to reproduce and further investigate these findings under conditions of inflammatory skin diseases in vivo. The project was part of a Collaborative Research Center of the German Research Foundation that aimed to develop and investigate a range of nanocarriers for topical delivery to the skin. The specific CMS architectures investigated here were hPG-C18-mPEG CMS (C18CMS) as well as hPG-PCL-mPEG CMS (bCMS). Both architectures have been developed at the Institute of Chemistry and Biochemistry, Freie Universität Berlin. C18CMS represent the prototypical CMS architecture, best characterized for topical delivery. bCMS are easily cleaved by esterases to improve long-term biocompatibility. As a model for a prototypical inflammatory skin condition, an oxazolone-induced mouse model with characteristics of atopic dermatitis (AD) was used. The cargo investigated was tacrolimus (TAC). TAC is a potent anti-inflammatory drug and one of the two main pharmacological treatment options for AD. With a relatively large molecular mass of 822 Da, it is considered at the threshold of substances that can penetrate into the skin in relevant amounts for topical treatment. In the first part of the project, the penetration of C18CMS into the skin, their potential systemic distribution, and the effect of oxazolone-induced inflammation on the penetration were investigated by fluorescence microscopy. Furthermore, the potential effects of the carriers on clinical and histological parameters were evaluated. In the second part of the project, the delivery of TAC by bCMS into inflamed skin, resulting systemic drug concentrations, as well as the clinical and histologic anti-inflammatory efficacy, were investigated. Under the conditions used, bCMS did not seem to increase the skin concentrations of the cargo drug in the viable skin compared to the standard ointment formulation. What is more, concentrations measured in the systemic circulation were significantly lower. This in fact suggests that bCMS decreased overall skin penetration. This differs from previous reports obtained using ex vivo/in vitro conditions, which consistently found penetration enhancement for TAC in bCMS and for various other cargo substances in multiple CMS architectures. Nevertheless, drug delivery to the skin and the anti-inflammatory efficacy of the formulation could be demonstrated. Although C18CMS penetrated into the stratum corneum, no penetration was observed into the viable layers of healthy skin. This penetration behavior of the carrier was not affected by oxazolone-induced dermatitis. The same was observed for bCMS in inflamed skin. These results seem to be partially in line with previous ex vivo/in vitro results under certain conditions, such as relatively short incubation times and relatively mild barrier alterations but differ from results under other conditions, such as longer incubation times and models of more severe barrier alterations. When modeling complete penetration of C18CMS through the viable skin, the fluorescently labeled carriers were found in the main sites of the mononuclear phagocyte system and particle clearance, i.e., the local lymph nodes, spleen, lung, liver, and kidney. No adverse effects were observed histologically. Overall, the results seem to confirm that CMS can be used for topical delivery and treatment of inflammatory skin conditions with TAC. However, CMS may not necessarily enhance penetration or efficacy. Moreover, the results suggest a potential systematic difference between ex vivo/in vitro and in vivo conditions. On the one hand, this cautions that murine models may be unsuitable to investigate the penetration enhancement effect of CMS. On the other hand, it suggests parameters that could potentially be optimized in ex vivo/in vitro models to increase predictability. Of these, particularly relevant parameters seem to be incubation times, exposure periods with subsequent removal of formulations, occlusion/hydration status, effects of repeated applications, steady-state conditions and drug depots, effects that depend on tissue layers other than the stratum corneum, and time-resolved kinetics. This may be particularly important when comparing water-based, volatile formulations with less volatile ointment formulations, and for drugs with comparatively high steady-state concentrations in the skin. With respect to the 3R principles, the results strongly suggest that no further in vivo studies should be performed to investigate the penetration enhancement effects of CMS or similar delivery solutions before 1.) a systematic analysis has shown what caused these discrepancies, 2.) all relevant aspects discussed have been modeled in vitro for the specific nanocarrier-drug combination in question, and 3.) an evidence-based estimate is available on whether the expected penetration enhancement would lead to a relevant benefit for the specific use case

Validation of the German version of the Schedule of Attitudes Toward Hastened Death (SAHD-D) with patients in palliative care

Objective: Reliable and validated instruments are needed in order to study the desire for hastened death (DHD). As there isno instrument in the German language to measure DHD, our aim was to validate a German version of the Schedule of Attitudes Toward Hastened Death (SAHD-D). Method: The SAHD was translated following guidelines promulgated by the European Organization for Research and Treatment of Cancer (EORTC). In eligible patients (clinical situation adequate, MMSE >= 21), the following instruments were employed: a symptom checklist (HOPE), the HADS-D (Hospital Anxiety and Depression Scale), the EORTC-QLQ-PAL15, and the SAHD-D, as well as an external estimation of DHD provided by the attending physician. A high level of DHD was defined as the mean plus one standard deviation (SD). Results: Of the 869 patients assessed, 92 were eligible for inclusion (66% females, mean age of 64.5 years). The SAHD-D total score ranged from 0 to 18, with a mean of 5 and a standard deviation (SD) of 3.7. A high level of DHD was found in 20% (n = 19). For discriminant validity, significant correlations were found between the SAHD-D and depression (r(rho) = 0.472), anxiety (r(rho) = 0.224), and clinical state (r(rho) = 0.178). For criterion validity, the external estimate of DHD showed a low significant correlation with patient score (r(rho) = 0.290). Factor analysis of the SAHD-D identified two factors. Significance of results: Validation of the SAHD-D illustrated good discriminant validity, confirming that a desire to hasten death is a construct separate from depression, anxiety, or physical state. The unidimensionality of the SAHD could not be reproduced. Our findings support the multifactorial interdependencies on DHD and suggest that the SAHD-D should be refined by considering actual wishes, general attitudes, and options of patients

Hippocampal subfield plasticity is associated with improved spatial memory

Abstract Physical exercise studies are generally underrepresented in young adulthood. Seventeen subjects were randomized into an intervention group (24.2 ± 3.9 years; 3 trainings/week) and 10 subjects into a passive control group (23.7 ± 4.2 years), over a duration of 6 months. Every two months, performance diagnostics, computerized spatial memory tests, and 3 Tesla magnetic resonance imaging were conducted. Here we find that the intervention group, compared to controls, showed increased cardiorespiratory fitness, spatial memory performance and subregional hippocampal volumes over time. Time-by-condition interactions occurred in right cornu ammonis 4 body and (trend only) dentate gyrus, left hippocampal tail and left subiculum. Increases in spatial memory performance correlated with hippocampal body volume changes and, subregionally, with left subicular volume changes. In conclusion, findings support earlier reports of exercise-induced subregional hippocampal volume changes. Such exercise-related plasticity may not only be of interest for young adults with clinical disorders of hippocampal function, but also for sedentary normal cohorts

Safety and Angiographic Efficacy of Intra-Arterial Fibrinolytics as Adjunct to Mechanical Thrombectomy : Results from the INFINITY Registry

Background and Purpose Data on safety and efficacy of intra-arterial (IA) fibrinolytics as adjunct to mechanical thrombectomy (MT) are sparse. Methods INtra-arterial FIbriNolytics In ThrombectomY (INFINITY) is a retrospective multi-center observational registry of consecutive patients with anterior circulation large-vessel occlusion ischemic stroke treated with MT and adjunctive administration of IA fibrinolytics (alteplase [tissue plasminogen activator, tPA] or urokinase [UK]) at 10 European centers. Primary outcome was the occurrence of symptomatic intracranial hemorrhage (sICH) according to the European Cooperative Acute Stroke Study II definition. Secondary outcomes were mortality and modified Rankin Scale (mRS) scores at 3 months. Results Of 5,612 patients screened, 311 (median age, 74 years; 44.1% female) received additional IA after or during MT (194 MT+IA tPA, 117 MT+IA UK). IA fibrinolytics were mostly administered for rescue of thrombolysis in cerebral infarction (TICI) 0-2b after MT (80.4%, 250/311). sICH occurred in 27 of 308 patients (8.8%), with an increased risk in patients with initial TICI0/1 (adjusted odds ratio [aOR], 2.3; 95% confidence interval [CI], 1.1 to 5.0 per TICI grade decrease) or in those with intracranial internal carotid artery occlusions (aOR, 3.7; 95% CI, 1.2 to 12.5). In patients with attempted rescue of TICI0-2b and available angiographic follow-up, 116 of 228 patients (50.9%) showed any angiographic reperfusion improvement after IA fibrinolytics, which was associated with mRS Conclusions Administration of IA fibrinolytics as adjunct to MT is performed rarely, but can improve reperfusion, which is associated with better outcomes. Despite a selection bias, an increased risk of sICH seems possible, which underlines the importance of careful patient selection.Peer reviewe

Nuclear Overhauser Enhancement imaging of glioblastoma at 7 Tesla: region specific correlation with apparent diffusion coefficient and histology.

To explore the correlation between Nuclear Overhauser Enhancement (NOE)-mediated signals and tumor cellularity in glioblastoma utilizing the apparent diffusion coefficient (ADC) and cell density from histologic specimens. NOE is one type of chemical exchange saturation transfer (CEST) that originates from mobile macromolecules such as proteins and might be associated with tumor cellularity via altered protein synthesis in proliferating cells.For 15 patients with newly diagnosed glioblastoma, NOE-mediated CEST-contrast was acquired at 7 Tesla (asymmetric magnetization transfer ratio (MTRasym) at 3.3ppm, B1 = 0.7 μT). Contrast enhanced T1 (CE-T1), T2 and diffusion-weighted MRI (DWI) were acquired at 3 Tesla and coregistered. The T2 edema and the CE-T1 tumor were segmented. ADC and MTRasym values within both regions of interest were correlated voxelwise yielding the correlation coefficient rSpearman (rSp). In three patients who underwent stereotactic biopsy, cell density of 12 specimens per patient was correlated with corresponding MTRasym and ADC values of the biopsy site.Eight of 15 patients showed a weak or moderate positive correlation of MTRasym and ADC within the T2 edema (0.16≤rSp≤0.53, p<0.05). Seven correlations were statistically insignificant (p>0.05, n = 4) or yielded rSp≈0 (p<0.05, n = 3). No trend towards a correlation between MTRasym and ADC was found in CE-T1 tumor (-0.31<rSp<0.28, p<0.05, n = 9; p>0.05, n = 6). The biopsy-analysis within CE-T1 tumor revealed a strong positive correlation between tumor cellularity and MTRasym values in two of the three patients (rSppatient3 = 0.69 and rSppatient15 = 0.87, p<0.05), while the correlation of ADC and cellularity was heterogeneous (rSppatient3 = 0.545 (p = 0.067), rSppatient4 = -0.021 (p = 0.948), rSppatient15 = -0.755 (p = 0.005)).NOE-imaging is a new contrast promising insight into pathophysiologic processes in glioblastoma regarding cell density and protein content, setting itself apart from DWI. Future studies might be based on the assumption that NOE-mediated CEST visualizes cellularity more accurately than ADC, especially in the CE-T1 tumor region

Additional file 1: of Dendritic Core-Multishell Nanocarriers in Murine Models of Healthy and Atopic Skin

Detailed Methods. (DOCX 40.1 kb