The effect of adipose tissue-derived stem cells in a middle cerebral artery occlusion stroke model depends on their engraftment rate

Background: In the field of experimental stem cell therapy, intra-arterial (IA) delivery yields the best results concerning, for example, migrated cell number at the targeted site. However, IA application also appears to be associated with increased mortality rates and infarction. Since many rodent studies systemically apply 1 × 106 cells, this could also be a consequence of engrafted cell number. The aim of this study was therefore to investigate the effect of different doses of adipose tissue-derived stem cells (ASCs) on engraftment rates and stroke outcome measured in vivo using 9.4-T high-field magnetic resonance imaging (MRI). Methods: Male Wistar rats (n = 43) underwent a middle cerebral artery occlusion (MCAo) for 45 or 90 min, followed by IA delivery of either saline or 1 × 106, 3 × 105, or 5 × 104 ASCs pre-labelled with very small superparamagnetic iron oxide particles (VSOPs). MRI (9.4-T) analysis was performed 48 h and 9 days post-MCAo. Lesion volumes were assessed by analysis of T2-weighted images and cell signal tracking showing cell engraftment and active cell migration by an improved T2*-analysis. Results: The ASC-derived signal intensity increased in the affected hemisphere 48 h post MCAo with injected cell number (p < 0.05). The analysis of stroke volumes revealed an increased infarction after injection of 1 × 106 ASCs compared to controls or application of 5 × 104 ASCs (p < 0.05). At 9 days post-MCAo, injection of 3 × 105 ASCs resulted in reduced infarct volumes (p < 0.05). Correspondingly, MRI analysis revealed no changes in cell numbers between both MRI examinations but showed active ASC migration to the site of infarction. Conclusion: Our results confirm that IA injection is an efficient way of targeting damaged brain tissue but its usefulness strongly depends on the right dose of delivered stem cells since this factor has a strong influence on migration rate and infarct volume, with better results for doses below 1 × 106 cells. Future challenges will include the determination of therapeutic doses for best cellular engraftment and stroke outcome

Sans fusibles : Les corps conducteurs de Claude Simon

Parmi les critiques allemands marqués par mai 1968, Lothar Baier (1942-2004) a sans doute été l’un des plus fins connaisseurs de la littérature et de la culture françaises modernes. Traducteur de Sartre et de Nizan, il a publié d’importants essais sur le roman du XXe siècle, notamment sur Céline et Giono, qu’il a recueillis dans son livre Französische Zustände (1982). Sa critique de la traduction des Corps conducteurs (Die Leitkörper), publiée le 14 novembre 1974 dans la Süddeutsche Zeitung, ..

Junco - Tieners en de Coronatijd - Een onderzoek in het Duits-Nederlands grensgebied

In 2020 hebben veel landen in de wereld te maken gekregen met een pandemie, veroorzaakt door het SARSCoV-2 virus (Roser, Ritchie, Ortiz-Ospina, & Hasell, 2021). In de volksmond ook wel coronavirus genoemd. De ziekteverschijnselen van dit virus wordt COVID-19 genoemd. Om de verspreiding van het coronavirus te vertragen zijn in sommige landen drastische maatregelen genomen om het sociale contact te beperken (Ritchie et al., 2021). Deze maatregelen hebben het dagelijks leven van veel mensen sterk veranderd. Tot op heden is er weinig betrouwbare informatie beschikbaar over de verschillende effecten van deze maatregelen

Additional file 2: Figure S1. of The effect of adipose tissue-derived stem cells in a middle cerebral artery occlusion stroke model depends on their engraftment rate

Influence of VSOP labelling on cell vitality and growth behaviour. LDH release did not differ for unlabelled (negative control) and VSOP-labelled ASCs. Both differed significantly from positive control. *p < 0.05 for negative control and VSOP-labelled cells vs. positive control (A). Growth curves and fraction of dead cells did not differ between labelled and unlabelled cells at any time (diagram). Growth curves of vital cells increased significantly during the observation period. VSOP density in cytoplasm decreased within 9 days (images). *p < 0.05 for increased cell growth up to 14 days for VSOP-labelled and unlabelled ASCs (B). ASC adipose tissue-derived stem cell, LDH lactate dehydrogenase, VSOP very small superparamagnetic iron oxide particles. (TIF 6166 kb